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Sample records for antimony thiosemicarbazone precursors

  1. Antimony

    Integrated Risk Information System (IRIS)

    Antimony ; CASRN 7440 - 36 - 0 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Effects

  2. Antimony Toxicity

    PubMed Central

    Sundar, Shyam; Chakravarty, Jaya

    2010-01-01

    Antimony toxicity occurs either due to occupational exposure or during therapy. Occupational exposure may cause respiratory irritation, pneumoconiosis, antimony spots on the skin and gastrointestinal symptoms. In addition antimony trioxide is possibly carcinogenic to humans. Improvements in working conditions have remarkably decreased the incidence of antimony toxicity in the workplace. As a therapeutic, antimony has been mostly used for the treatment of leishmaniasis and schistosomiasis. The major toxic side-effects of antimonials as a result of therapy are cardiotoxicity (~9% of patients) and pancreatitis, which is seen commonly in HIV and visceral leishmaniasis co-infections. Quality control of each batch of drugs produced and regular monitoring for toxicity is required when antimonials are used therapeutically. PMID:21318007

  3. Alumina-supported bimetallics of palladium alloyed with germanium, tin, lead, or antimony from organometallic precursors I. Preparation and characterization

    SciTech Connect

    Aduriz, H.R.; Bodnariuk, P. , Bahia Blanca ); Coq, B.; Figueras, F. )

    1989-09-01

    Bimetallic PdSn, PdSb, PdPb, and PdGe on alumina catalysts with a low metal content have been prepared using either chloride or organometallic precursors. For the catalysts obtained from chloride precursors no interaction was observed between the two metals, and the catalysts behaved like pure Pd/Al{sub 2}O{sub 3}. In contrast, the reactions of (C{sub 4}H{sub 9}){sub 4}Sn, (C{sub 4}H{sub 9}){sub 4}Pb, (C{sub 4}H{sub 9}){sub 4}Ge, or (C{sub 4}H{sub 9}){sub 3}Sb in n-heptane solution with reduced Pd/Al{sub 2}O{sub 3} catalyst yielded a supported alloy. The interaction between metallic palladium and the organic modifier is highly selective and leads to the formation of a well-tailored bimetallic catalyst. When these final solids are reduced at 573 or 773 K, the second metal locates preferentially at the outer layer of the bimetallic aggregates. After reduction at 773 K large metallic aggregates are obtained (particle size 15 nm), and the formation of {beta}-palladium hydride, which can be formed with pure palladium catalysts, is suppressed by the addition of a small amount of the second metal. The specific activity of the palladium surface atoms for isoprene hydrogenation is then lowered, and the selectivity increased.

  4. Antimony trioxide

    Integrated Risk Information System (IRIS)

    Antimony trioxide ; CASRN 1309 - 64 - 4 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogeni

  5. Ethoxy and silsesquioxane derivatives of antimony as dopant precursors: unravelling the structure and thermal stability of surface species on SiO2.

    PubMed

    Alphazan, T; Florian, P; Thieuleux, C

    2017-03-14

    We report here the controlled preparation of SiO2 supported Sb-(mono)layers and their thorough characterization by in situ IR, solid-state NMR and elemental analyses. This study allows for the molecular understanding of the surface Sb species derived from the grafting of ethoxy and polyhedral oligomeric silsesquioxane antimony derivatives as mono- or bi-podal Sb(iii) surface species depending on the number of surface SiOH groups. This result is different from what was observed with the phosphorus analogue (POSS-P) that yielded P(v) species. A monolayer coverage of Sb species onto silica was also obtained using both POSS-Sb and the [Sb(OEt)3]2 derivative with surface densities ranging from ∼0.3 Sb nm(-2) to 1.8 Sb nm(-2), respectively. It is noteworthy that under optimized conditions, a layer of antimony species or suboxides on silica was produced using POSS-Sb without significant Sb loss, highlighting the protective properties of the POSS cage. These results open new perspectives for the controlled and non-destructive Sb-doping (Molecular Layer Doping) of semiconductors dedicated to nano-device applications.

  6. Antimony: a flame fighter

    USGS Publications Warehouse

    Wintzer, Niki E.; Guberman, David E.

    2015-01-01

    In the 11th century, the word antimonium was used by medieval scholar Constantinus Africanus, but antimony metal was not isolated until the 16th century by Vannoccio Biringuccio, an Italian metallurgist. In the early 18th century, chemist Jons Jakob Berzelius chose the periodic symbol for antimony (Sb) based on stibium, which is the Latin name for stibnite.

  7. Epitaxial Silicon Doped With Antimony

    NASA Technical Reports Server (NTRS)

    Huffman, James E.; Halleck, Bradley L.

    1996-01-01

    High-purity epitaxial silicon doped with antimony made by chemical vapor deposition, using antimony pentachloride (SbCI5) as source of dopant and SiH4, SiCI2H2, or another conventional source of silicon. High purity achieved in layers of arbitrary thickness. Epitaxial silicon doped with antimony needed to fabricate impurity-band-conduction photodetectors operating at wavelengths from 2.5 to 40 micrometers.

  8. Oligosilanylated Antimony Compounds

    PubMed Central

    2015-01-01

    By reactions of magnesium oligosilanides with SbCl3, a number of oligosilanylated antimony compounds were obtained. When oligosilanyl dianions were used, either the expected cyclic disilylated halostibine was obtained or alternatively the formation of a distibine was observed. Deliberate formation of the distibine from the disilylated halostibine was achieved by reductive coupling with C8K. Computational studies of Sb–Sb bond energies, barriers of pyramidal inversion at Sb, and the conformational behavior of distibines provided insight for the understanding of the spectroscopic properties. PMID:25937691

  9. [Study of the effect of thiosemicarbazones against Toxoplasma gondii].

    PubMed

    Gomes, Marco Antônio G B; Carreira, Gabriela M; Souza, Daniela P V; Nogueira, Paulo Marcos R; de Melo, Edésio J T; Maria, Edmilson J

    2013-04-01

    Toxoplasmosis is a neglected disease, with an estimated occurrence of one-third of the population worldwide. Research in medicinal chemistry has for some years been pursuing the development of new drugs against toxoplasmosis, because current treatments cause serious side effects in the patient. The use of thiosemicarbazones as an alternative option for the treatment of various diseases has been published in recent years, due to their, among others, anticancer, antimalarial, antitrypanosomal, antibacterial, and antitoxoplasmosis activities, the latter being the subject of this study, which is based upon biological analyses and tests of the response of Toxoplasma gondii in the presence of thiosemicarbazones.

  10. Antimony activities in copper mattes

    NASA Astrophysics Data System (ADS)

    Hino, M.; Toguri, J. M.

    1987-03-01

    A mass spectrometric technique combined with a double Knudsen cell was used to determine the antimony and copper activities in the Cu-Sb binary system at 1373 K and in the two-melt composition range of the Cu-S-Sb ternary system at 1423 K. The antimony and copper activities were calculated based on the intensity ration of the gaseous Sb and Cu species, over the unknown and known activity samples, respectively. γ{Sb/o} were found to be 1.1×10-2 in molten copper at 1373 K, and 1.8×10-2 and 0.44 in a copper-rich phase and in a matter phase, of the Cu-S-Sb ternary system at 1423 K, respectively. These values indicate, that antimony can be removed during the matte smelting and slagging stage of the copper smelting process. Interaction parameters of antimony in molten copper slagging stage of the copper smelting process. Interaction parameters of antimony in molten copper at 1423 K were calculated and found to be 10.7, -5.4, and 6.3 for ɛ{Sb/Sb} · ρSb Sb, and ɛ{Sb/S}, respectively.

  11. Organometallic ruthenium complexes with thiosemicarbazone ligands: Synthesis, structure and cytotoxicity of [(η6-p-cymene)Ru(NS)Cl]+ (NS = 9-anthraldehyde thiosemicarbazones)

    PubMed Central

    Beckford, Floyd A.; Leblanc, Gabriel; Thessing, Jeffrey; Shaloski, Michael; Frost, Brian J.; Li, Liya; Seeram, Navindra P.

    2009-01-01

    A series of half-sandwich arene-ruthenium complexes of the type [(η6-p-cymene) Ru(thiosemicarbazone)Cl]+ have been synthesized and their biological activity investigated. The first structurally characterized arene-ruthenium half-sandwich complex with a thiosemicarbazone ligand is reported. PMID:20160909

  12. Mineral Resource of the Month: Antimony

    USGS Publications Warehouse

    Guberman, David E.

    2015-01-01

    Antimony is a lustrous silvery-white semimetal or metalloid. Archaeological and historical studies indicate that antimony and its mineral sulfides have been used by humans for at least six millennia. The alchemist Basil Valentine is sometimes credited with “discovering” the element; he described the extraction of metallic antimony from stibnite in his treatise “The Triumphal Chariot of Antimony,” published sometime between 1350 and 1600. In the early 18th century, Jöns Jakob Berzelius chose the periodic symbol for antimony (Sb) based on stibium, which is the Latin name for stibnite.

  13. Effect of different precursors on generation of reference spectra for structural molecular background correction by solid sampling high-resolution continuum source graphite furnace atomic absorption spectrometry: Determination of antimony in cosmetics.

    PubMed

    Barros, Ariane Isis; Victor de Babos, Diego; Ferreira, Edilene Cristina; Gomes Neto, José Anchieta

    2016-12-01

    Different precursors were evaluated for the generation of reference spectra and correction of the background caused by SiO molecules in the determination of Sb in facial cosmetics by high-resolution continuum source graphite furnace atomic absorption spectrometry employing direct solid sample analysis. Zeolite and mica were the most effective precursors for background correction during Sb determination using the 217.581nm and 231.147nm lines. Full 2(3) factorial design and central composite design were used to optimize the atomizer temperature program. The optimum pyrolysis and atomization temperatures were 1500 and 2100°C, respectively. A Pd(NO3)2/Mg(NO3)2 mixture was employed as the chemical modifier, and calibration was performed at 217.581nm with aqueous standards containing Sb in the range 0.5-2.25ng, resulting in a correlation coefficient of 0.9995 and a slope of 0.1548s ng(-1). The sample mass was in the range 0.15-0.25mg. The accuracy of the method was determined by analysis of Montana Soil (II) certified reference material, together with addition/recovery tests. The Sb concentration found was in agreement with the certified value, at a 95% confidence level (paired t-test). Recoveries of Sb added to the samples were in the range 82-108%. The limit of quantification was 0.9mgkg(-1) and the relative standard deviation (n=3) ranged from 0.5% to 7.1%. From thirteen analyzed samples, Sb was not detected in ten samples (blush, eye shadow and compact powder); three samples (two blush and one eye shadow) presented Sb concentration in the 9.1-14.5mgkg(-1) range.

  14. Synthesis and biochemical evaluation of benzoylbenzophenone thiosemicarbazone analogues as potent and selective inhibitors of cathepsin L

    PubMed Central

    Parker, Erica N.; Song, Jiangli; Kumar, G. D. Kishore; Odutola, Samuel O.; Chavarria, Gustavo E.; Charlton-Sevcik, Amanda K.; Strecker, Tracy E.; Barnes, Ashleigh L.; Sudhan, Dhivya R.; Wittenborn, Thomas R.; Siemann, Dietmar W.; Horsman, Michael R.; Chaplin, David J.; Trawick, Mary Lynn; Pinney, Kevin G.

    2016-01-01

    Upregulation of cathepsin L in a variety of tumors and its ability to promote cancer cell invasion and migration through degradation of the extracellular matrix suggest that cathepsin L is a promising biological target for the development of anti-metastatic agents. Based on encouraging results from studies on benzophenone thiosemicarbazone cathepsin inhibitors, a series of fourteen benzoylbenzophenone thiosemicarbazone analogues were designed, synthesized, and evaluated for their inhibitory activity against cathepsins L and B. Thiosemicarbazone inhibitors 3-benzoylbenzophenone thiosemicarbazone 1, 1,3-bis(4-fluorobenzoyl)benzene thiosemicarbazone 8, and 1,3-bis(2-fluorobenzoyl)-5-bromobenzene thiosemicarbazone 32 displayed the greatest potency against cathepsin L with low IC50 values of 9.9 nM, 14.4 nM, and 8.1 nM, respectively. The benzoylbenzophenone thiosemicarbazone analogues evaluated were selective in their inhibition of cathepsin L compared to cathepsin B. Thiosemicarbazone analogue 32 inhibited invasion through Matrigel of MDA-MB-231 breast cancer cells by 70% at 10 μM. Thiosemicarbazone analogue 8 significantly inhibited the invasive potential of PC-3ML prostate cancer cells by 92% at 5 μM. The most active cathepsin L inhibitors from this benzoylbenzophenone thiosemicarbazone series (1, 8, and 32) displayed low cytotoxicity toward normal primary cells [in this case human umbilical vein endothelial cells (HUVECs)]. In an initial in vivo study, 3-benzoylbenzophenone thiosemicarbazone (1) was well-tolerated in a CDF1 mouse model bearing an implanted C3H mammary carcinoma, and showed efficacy in tumor growth delay. Low cytotoxicity, inhibition of cell invasion, and in vivo tolerability are desirable characteristics for anti-metastatic agents functioning through an inhibition of cathepsin L. Active members of this structurally diverse group of benzoylbenzophenone thiosemicarbazone cathepsin L inhibitors show promise as potential anti-metastatic, pre

  15. Synthesis and biochemical evaluation of benzoylbenzophenone thiosemicarbazone analogues as potent and selective inhibitors of cathepsin L.

    PubMed

    Parker, Erica N; Song, Jiangli; Kishore Kumar, G D; Odutola, Samuel O; Chavarria, Gustavo E; Charlton-Sevcik, Amanda K; Strecker, Tracy E; Barnes, Ashleigh L; Sudhan, Dhivya R; Wittenborn, Thomas R; Siemann, Dietmar W; Horsman, Michael R; Chaplin, David J; Trawick, Mary Lynn; Pinney, Kevin G

    2015-11-01

    Upregulation of cathepsin L in a variety of tumors and its ability to promote cancer cell invasion and migration through degradation of the extracellular matrix suggest that cathepsin L is a promising biological target for the development of anti-metastatic agents. Based on encouraging results from studies on benzophenone thiosemicarbazone cathepsin inhibitors, a series of fourteen benzoylbenzophenone thiosemicarbazone analogues were designed, synthesized, and evaluated for their inhibitory activity against cathepsins L and B. Thiosemicarbazone inhibitors 3-benzoylbenzophenone thiosemicarbazone 1, 1,3-bis(4-fluorobenzoyl)benzene thiosemicarbazone 8, and 1,3-bis(2-fluorobenzoyl)-5-bromobenzene thiosemicarbazone 32 displayed the greatest potency against cathepsin L with low IC50 values of 9.9 nM, 14.4 nM, and 8.1 nM, respectively. The benzoylbenzophenone thiosemicarbazone analogues evaluated were selective in their inhibition of cathepsin L compared to cathepsin B. Thiosemicarbazone analogue 32 inhibited invasion through Matrigel of MDA-MB-231 breast cancer cells by 70% at 10 μM. Thiosemicarbazone analogue 8 significantly inhibited the invasive potential of PC-3ML prostate cancer cells by 92% at 5 μM. The most active cathepsin L inhibitors from this benzoylbenzophenone thiosemicarbazone series (1, 8, and 32) displayed low cytotoxicity toward normal primary cells [in this case human umbilical vein endothelial cells (HUVECs)]. In an initial in vivo study, 3-benzoylbenzophenone thiosemicarbazone (1) was well-tolerated in a CDF1 mouse model bearing an implanted C3H mammary carcinoma, and showed efficacy in tumor growth delay. Low cytotoxicity, inhibition of cell invasion, and in vivo tolerability are desirable characteristics for anti-metastatic agents functioning through an inhibition of cathepsin L. Active members of this structurally diverse group of benzoylbenzophenone thiosemicarbazone cathepsin L inhibitors show promise as potential anti-metastatic, pre

  16. Gold(III) complexes with ONS-Tridentate thiosemicarbazones: Toward selective trypanocidal drugs.

    PubMed

    Rettondin, Andressa R; Carneiro, Zumira A; Gonçalves, Ana C R; Ferreira, Vanessa F; Oliveira, Carolina G; Lima, Angélica N; Oliveira, Ronaldo J; de Albuquerque, Sérgio; Deflon, Victor M; Maia, Pedro I S

    2016-09-14

    Tridentate thiosemicarbazone ligands with an ONS donor set, H2L(R) (R = Me and Et) were prepared by reactions of 1-phenyl-1,3-butanedione with 4-R-3-thiosemicarbazides. H2L(R) reacts with Na[AuCl4]·2H2O in MeOH in a 1:1 M ratio under formation of green gold(III) complexes of composition [AuCl(L(R))]. These compounds represent the first examples of gold(III) complexes with ONS chelate-bonded thiosemicarbazones. The in vitro anti-Trypanosoma cruzi activity against both trypomastigote and amastigote forms (IC50try/ama) of CL Brener strains as well as the cytotoxicity against LLC-MK2 cells of the free ligands and complexes was evaluated. The complex [AuCl(L(Me))] was found to be more active and more selective than its precursor ligand and the standard drug benznidazole with a SItry/ama value higher than 200, being considered as a lead candidate for Chagas disease treatment. Moreover the in vitro activity against the replicative amastigote form (IC50ama) of T. cruzi was additionally investigated revealing that [AuCl(L(Me))] was also more potent than benznidazole still with a similar selectivity index. Finally, docking studies showed that free ligands and complexes interact with the same residues of the parasite protease cruzain but with different intensities, suggesting that this protease could be a possible target for the trypanocidal action of the obtained compounds.

  17. Transparent conducting aerogels of antimony-doped tin oxide.

    PubMed

    Correa Baena, Juan Pablo; Agrios, Alexander G

    2014-11-12

    Bulk antimony-doped tin oxide aerogels are prepared by epoxide-initiated sol-gel processing. Tin and antimony precursors are dissolved in ethanol and water, respectively, and propylene oxide is added to cause rapid gelation of the sol, which is then dried supercritically. The Sb:Sn precursor mole ratio is varied from 0 to 30% to optimize the material conductivity and absorbance. The materials are characterized by electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy (XPS), nitrogen physisorption analysis, a four-point probe resistivity measurement, and UV-vis diffuse reflectance spectroscopy. The samples possess morphology typical of aerogels without significant change with the amount of doping. Calcination at 450 °C produces a cassiterite crystal structure in all aerogel samples. Introduction of Sb at 15% in the precursor (7.6% Sb by XPS) yields a resistivity more than 3 orders of magnitude lower than an undoped SnO2 aerogel. Calcination at 800 °C reduces the resistivity by an additional 2 orders of magnitude to 30 Ω·cm, but results in a significant decrease in surface area and pore volume.

  18. FIRST REPORT ON OTOTOXICITY OF MEGLUMINE ANTIMONIATE

    PubMed Central

    Valete-Rosalino, Cláudia Maria; Araujo-Melo, Maria Helena; Bezerra, Débora Cristina de Oliveira; de Barcelos, Renata Oliveira; de Melo-Ferreira, Vanessa; Torraca, Tânia Salgado de Sousa; Martins, Ana Cristina da Costa; Moreira, João Soares; Vargas, Mirian Catherine Melgares; Braga, Frederico Pereira Bom; Salgueiro, Mariza de Matos; Saheki, Maurício Naoto; Schubach, Armando Oliveira

    2014-01-01

    Introduction: Pentavalent antimonials are the first drug of choice in the treatment of tegumentary leishmaniasis. Data on ototoxicity related with such drugs is scarcely available in literature, leading us to develop a study on cochleovestibular functions. Case Report: A case of a tegumentary leishmaniasis patient, a 78-year-old man who presented a substantial increase in auditory threshold with tinnitus and severe rotatory dizziness during the treatment with meglumine antimoniate, is reported. These symptoms worsened in two weeks after treatment was interrupted. Conclusion: Dizziness and tinnitus had already been related to meglumine antimoniate. However, this is the first well documented case of cochlear-vestibular toxicity related to meglumine antimoniate. PMID:25229226

  19. Mineral resource of the month: antimony

    USGS Publications Warehouse

    ,

    2008-01-01

    The article describes the characteristics and industrial uses of antimony. Antimony, which is produced as a byproduct of mining other metals such as gold, lead or silver, is used in everything from flame retardants, batteries, ceramics and glass. It is also used in glass for television picture tubes, computer monitors, pigments and catalysts.

  20. Heteronuclear compounds of arsenic and antimony

    NASA Astrophysics Data System (ADS)

    Mauser, James E.

    1982-09-01

    Volatilization of secondary metals such as arsenic, antimony, and bismuth, during the smelting of copper ores, is important because of environmental and resource considerations. The Bureau of Mines, United States Department of the Interior, has been studying copper concentrate roasting in conjunction with the volatility of these minor constituents. Some unusual vaporization behavior initiated this supplemental paper which shows that when the mixed sulfides of arsenic and antimony are heated, the volatilization of arsenic is retarded and the volatilization of antimony increased. Mixed oxides of arsenic and antimony also exhibit exceptional volatilization behavior. These anomalous vaporization behaviors are attributed to the formation of heteronuclear compounds of arsenic and antimony, but the colligative properties of solutions may also be a factor.

  1. Isatin based thiosemicarbazone derivatives as potential bioactive agents: Anti-oxidant and molecular docking studies

    NASA Astrophysics Data System (ADS)

    Haribabu, J.; Subhashree, G. R.; Saranya, S.; Gomathi, K.; Karvembu, R.; Gayathri, D.

    2016-04-01

    A new series of isatin based thiosemicarbazones has been synthesized from benzylisatin and unsubstituted/substituted thiosemicarbazides (1-5). The synthesized compounds were characterized by elemental analyses, and UV-Visible, FT-IR, 1H &13C NMR and mass spectroscopic techniques. Three dimensional molecular structure of three compounds (1, 3 and 4) was determined by single crystal X-ray crystallography. Anti-oxidant activity of the thiosemicarbazone derivatives showed their excellent scavenging effect against free radicals. In addition, all the compounds showed good anti-haemolytic activity. In silico molecular docking studies were performed to screen the anti-inflammatory and anti-tuberculosis properties of thiosemicarbazone derivatives.

  2. Antimony and silicon environments in antimony silicate glasses

    SciTech Connect

    Mee, M.; Davies, B.C.; Orman, R.G.; Thomas, M.F.; Holland, D.

    2010-09-15

    Antimony silicate glasses, of general formula xSb{sub 2}O{sub 3}.(1-x)SiO{sub 2} (0.1{<=}x{<=}0.78), have been prepared by melt-quenching and their structures studied using {sup 29}Si MAS NMR spectroscopy, {sup 121}Sb Moessbauer spectroscopy and Raman spectroscopy. Oxidation during melting gives rise to Sb{sup 5+} in concentrations, which increase linearly with x to give a value of {approx}10% when x=0.78. {sup 121}Sb Moessbauer spectra show Moessbauer shifts and quadrupole splittings consistent with Sb{sup 3+} in a [:SbO{sub 3}] trigonal pyramid, similar to that in crystalline Sb{sub 2}O{sub 3}. A broad band in the Raman spectrum at {approx}410 cm{sup -1} is due to the vibrations of such a unit. The dependence of the silicon Q{sup n} speciation on x can be interpreted by the formation of Sb-O-Sb links possibly to form rings of 4 [:SbO{sub 3}] units such as are found in valentinite. - Graphical abstract: Antimony silicate glasses have been shown to contain Sb{sup 3+} in [:SbO{sub 3}] trigonal pyramid units using {sup 121}Sb Moessbauer spectroscopy and Raman spectroscopy. {sup 29}Si magic-angle-spinning NMR has shown silicon Q{sup n} speciation which can be interpreted as formation of rings of 4 [:SbO{sub 3}] units such as are found in valentinite.

  3. Antimony-doped graphene nanoplatelets

    PubMed Central

    Jeon, In-Yup; Choi, Min; Choi, Hyun-Jung; Jung, Sun-Min; Kim, Min-Jung; Seo, Jeong-Min; Bae, Seo-Yoon; Yoo, Seonyoung; Kim, Guntae; Jeong, Hu Young; Park, Noejung; Baek, Jong-Beom

    2015-01-01

    Heteroatom doping into the graphitic frameworks have been intensively studied for the development of metal-free electrocatalysts. However, the choice of heteroatoms is limited to non-metallic elements and heteroatom-doped graphitic materials do not satisfy commercial demands in terms of cost and stability. Here we realize doping semimetal antimony (Sb) at the edges of graphene nanoplatelets (GnPs) via a simple mechanochemical reaction between pristine graphite and solid Sb. The covalent bonding of the metalloid Sb with the graphitic carbon is visualized using atomic-resolution transmission electron microscopy. The Sb-doped GnPs display zero loss of electrocatalytic activity for oxygen reduction reaction even after 100,000 cycles. Density functional theory calculations indicate that the multiple oxidation states (Sb3+ and Sb5+) of Sb are responsible for the unusual electrochemical stability. Sb-doped GnPs may provide new insights and practical methods for designing stable carbon-based electrocatalysts. PMID:25997811

  4. Antimony-doped graphene nanoplatelets

    NASA Astrophysics Data System (ADS)

    Jeon, In-Yup; Choi, Min; Choi, Hyun-Jung; Jung, Sun-Min; Kim, Min-Jung; Seo, Jeong-Min; Bae, Seo-Yoon; Yoo, Seonyoung; Kim, Guntae; Jeong, Hu Young; Park, Noejung; Baek, Jong-Beom

    2015-05-01

    Heteroatom doping into the graphitic frameworks have been intensively studied for the development of metal-free electrocatalysts. However, the choice of heteroatoms is limited to non-metallic elements and heteroatom-doped graphitic materials do not satisfy commercial demands in terms of cost and stability. Here we realize doping semimetal antimony (Sb) at the edges of graphene nanoplatelets (GnPs) via a simple mechanochemical reaction between pristine graphite and solid Sb. The covalent bonding of the metalloid Sb with the graphitic carbon is visualized using atomic-resolution transmission electron microscopy. The Sb-doped GnPs display zero loss of electrocatalytic activity for oxygen reduction reaction even after 100,000 cycles. Density functional theory calculations indicate that the multiple oxidation states (Sb3+ and Sb5+) of Sb are responsible for the unusual electrochemical stability. Sb-doped GnPs may provide new insights and practical methods for designing stable carbon-based electrocatalysts.

  5. Surface complexation of antimony on kaolinite.

    PubMed

    Rakshit, Sudipta; Sarkar, Dibyendu; Datta, Rupali

    2015-01-01

    Geochemical fate of antimony (Sb) - a similar oxyanion as arsenic (As) - in a variety of environment is largely unexplored. Kaolinite is an important, naturally occurring clay mineral in soils and aquifers and is known to control the fate of several contaminants via a multitude of geochemical processes, primarily adsorption. Here we report adsorption of antimony on kaolinite as a function of solution chemistry: initial antimony concentration, pH, ionic strength, and a competing anion. A surface complexation modeling (SCM) approach was undertaken to understand the potential mechanistic implications of sorption envelope data. In the SCM, a multicomponent additive approach, in which kaolinite is assumed to be a (1:1) mixture of quartz (≡SiOH) and gibbsite (≡AlOH), was tested. Results indicated that ionic strength has a minimal effect on antimony adsorption. For the lower initial antimony concentration (4.11 μM), the additive model with binuclear surface complexes on quartz and gibbsite showed a better fit at pH<6, but somewhat under predicted the experimental data above pH 6. At the higher initial antimony concentration (41.1 μM), the sorption envelope was of different shape than the lower load. The additive model, which considered binuclear surface complexes for quartz and gibbsite, resulted in over prediction of the adsorption data at pH>3.5. However, the additive model with binuclear surface complex on quartz and mononuclear surface complex on gibbsite showed an excellent fit of the data. Phosphate greatly influenced antimony adsorption on kaolinite at both low and high antimony loadings, indicating competition for available surface sites.

  6. 40 CFR 721.1930 - Butanoic acid, antimony (3=) salt.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Butanoic acid, antimony (3=) salt. 721... Substances § 721.1930 Butanoic acid, antimony (3=) salt. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as butanoic acid, antimony (3=) salt (PMN...

  7. 40 CFR 721.1930 - Butanoic acid, antimony (3=) salt.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Butanoic acid, antimony (3=) salt. 721... Substances § 721.1930 Butanoic acid, antimony (3=) salt. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as butanoic acid, antimony (3=) salt (PMN...

  8. 40 CFR 721.1930 - Butanoic acid, antimony (3=) salt.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Butanoic acid, antimony (3=) salt. 721... Substances § 721.1930 Butanoic acid, antimony (3=) salt. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as butanoic acid, antimony (3=) salt (PMN...

  9. The Membrane Electrowinning Separation of Antimony from a Stibnite Concentrate

    NASA Astrophysics Data System (ADS)

    Yang, Jian-Guang; Yang, Sheng-Hai; Tang, Chao-Bo

    2010-06-01

    The main purpose of this study was to characterize and to extract antimony from a stibnite concentrate through electrowinning. This article reports an account of a study conducted on the optimization of the process parameters for antimony pentachloride circular leaching, purification, and electrowinning of antimony from antimony trichloride solution. The effect of electrowinning parameters, such as antimony and sodium chloride concentration in the catholyte, temperature, current density, polar distance, etc., on the voltage requirement and the current efficiency (CE) of antimony electrodeposition was explored. A maximum CE of more than 97 pct was attained with a catholyte composition of 70-g/L antimony, 25-g/L NaCl, 4.5-mol/L hydrogen ion concentration, with an anolyte composition of 40-g/L antimony trichloride at a temperature of 328 K (55 °C), a 4-cm polar distance, and a cathode current density of 200 A/m2. Under the optimized conditions, the CE was more than 97 pct, and a 99.98 pct antimony plate was obtained on the cathode. The chemical content analysis of the resulting anolyte was indicated to be 97 pct antimony pentachloride and 3 pct antimony trichloride, which could be recycled to leaching tank as the leaching agent.

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

    USGS Publications Warehouse

    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.”

  11. Microbial Antimony Biogeochemistry: Enzymes, Regulation, and Related Metabolic Pathways

    PubMed Central

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

    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.” PMID:27342551

  12. Spectral studies of copper(II) complexes of 6-(3-thienyl) pyridine-2-thiosemicarbazone

    SciTech Connect

    Mahjoub, Omima Abdalla; Farina, Yang

    2014-09-03

    Two novel copper(II) complexes [Cu(HL)Cl]Cl.H{sub 2}O (1) and [Cu(L)NO{sub 3}]Ðœ‡H{sub 2}O (2) of the three NNS donor thiosemicarbazone ligand 6-(3-thienyl) pyridine-2-thiosemicarbazone have been synthesized. The ligand and its copper(II) complexes were characterized by elemental analysis (C, H, N, and S), FT-IR, UV-visible, magnetic susceptibility and molar conductance. The thiosemicarbazone is present either as the thione form in complex 1 or as thiol form in complex 2 and is coordinated to copper(II) atom via the pyridine nitrogen atom, the azomethine nitrogen atom and the sulfur atom. The physicochemical and spectral data suggest square planar geometry for copper(II) atoms.

  13. The Diffusion of Antimony of Alpha Iron.

    DTIC Science & Technology

    Diffusion coefficients of antimony in alpha iron were determined in the temperature range 700 to 900C using the residual activity method. Specimens...negligible effect on the diffusion of antomony in alpha iron . These results are discussed in relation to the phenomenon of temper brittleness in steels

  14. Intermolecular interaction of thiosemicarbazone derivatives to solvents and a potential Aedes aegypti target

    NASA Astrophysics Data System (ADS)

    da Silva, João Bosco P.; Hallwass, Fernando; da Silva, Aluizio G.; Moreira, Diogo Rodrigo; Ramos, Mozart N.; Espíndola, José Wanderlan P.; de Oliveira, Ana Daura T.; Brondani, Dalci José; Leite, Ana Cristina L.; Merz, Kenneth M.

    2015-08-01

    DFT calculations were used to access information about structure, energy and electronic properties of series of phenyl- and phenoxymethyl-(thio)semicarbazone derivatives with demonstrated activity against the larvae of Aedes aegypti in stage L4. The way as the thiosemicarbazone derivatives can interact with solvents like DMSO and water were analyzed from the comparison between calculated and experimental 1H NMR chemical shifts. The evidences of thiosemicarbazone derivatives making H-bond interaction to solvent have provide us insights on how they can interact with a potential A. aegypti's biological target, the Sterol Carrier Protein-2.

  15. Effect of the Metal Ion on the Enantioselectivity and Linkage Isomerization of Thiosemicarbazone Helicates.

    PubMed

    Romero, María J; Suárez, Vanesa; Fernández-Fariña, Sandra; Maneiro, Marcelino; Martínez-Núñez, Emilio; Zaragoza, Guillermo; González-Noya, Ana M; Pedrido, Rosa

    2017-04-06

    The effect of the metal ion and ligand design on the enantioselectivity and linkage isomerization of neutral cobalt and zinc bisthiosemicarbazone metallohelicates has been investigated in this work. The electrochemical synthesis has afforded the enantioselective formation of chirally pure cobalt helicates, and the ΛΛ isomer of a single enantiomer has been crystallized as only product for the cobalt methyl-substituted thiosemicarbazone helicate. Interestingly linkage isomers have been formed from zinc ethyl-substituted thiosemicarbazone helicate enantiomers for the first time. The co-existence of these isomers has been evaluated from the point of view of both experimental results and computational calculations.

  16. A novel series of thiosemicarbazone drugs: From synthesis to structure

    NASA Astrophysics Data System (ADS)

    Ebrahimi, Hossein Pasha; Hadi, Jabbar S.; Alsalim, Tahseen A.; Ghali, Thaer S.; Bolandnazar, Zeinab

    2015-02-01

    A new series of thiosemicarbazones (TSCs) and their 1,3,4-thiadiazolines (TDZs) containing acetamide group have been synthesized from thiosemicarbazide compounds by the reaction of TSCs with cyclic ketones as well as aromatic aldehydes. The structures of newly synthesized 1,3,4-thiadiazole derivatives obtained by heterocyclization of the TSCs with acetic anhydride were experimentally characterized by spectral methods using IR, 1H NMR, 13C NMR and mass spectroscopic methods. Furthermore, the structural, thermodynamic, and electronic properties of the studied compounds were also studied theoretically by performing Density Functional Theory (DFT) to access reliable results to the experimental values. The molecular geometry, the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO) and Mulliken atomic charges of the studied compounds have been calculated at the B3LYP method and standard 6-31+G(d,p) basis set starting from optimized geometry. The theoretical 13C chemical shift results were also calculated using the gauge independent atomic orbital (GIAO) approach and their respective linear correlations were obtained.

  17. Resistance mechanisms to arsenicals and antimonials.

    PubMed

    Rosen, B P

    1995-01-01

    Salts and organic derivatives of arsenic and antimony are quite toxic. Living organisms have adapted to this toxicity by the evolution of resistance mechanisms. Both prokaryotic and eukaryotic cells develop resistance when exposed to arsenicals or antimonials. In the case of bacteria resistance is conferred by plasmid-encoded arsenical resistance (ars) operons. The genes and gene products of the ars operon of the clinically-isolated conjugative R-factor R773 have been identified and their mechanism of action elucidated. The operon encodes an ATP-driven pump that extrudes arsenite and antimonite from the cells. The lowering of their intracellular concentration results in resistance. Arsenate resistance results from the action of the plasmid-encoded arsenate reductase that reduces arsenate to arsenite, which is then pumped out of the cell.

  18. Calcium release induced by 2-pyridinecarboxaldehyde thiosemicarbazone and its copper complex contributes to tumor cell death.

    PubMed

    Fu, Yun; Liu, Youxun; Wang, Jiangang; Li, Cuiping; Zhou, Sufeng; Yang, Yun; Zhou, Pingxin; Lu, Chengbiao; Li, Changzheng

    2017-03-01

    Thiosemicarbazones display significant antitumor activity and their copper complexes also exhibit enhanced biological activities in most situations, but the underlying mechanism is poorly understood. Therefore, investigation of the mechanism involved in the change upon chelation is required to extend our understanding of the effects of thiosemicarbazones. In the present study, the inhibitory effect of 2-pyridinecarboxaldehyde thiosemicarbazone (PCT) and its copper complex (PCT-Cu) on cell proliferation was investigated. The copper chelate exhibited a 3- to 10-fold increase in antitumor activity (with an IC50 <5 µM). The results showed that both PCT and PCT-Cu induced reactive oxygen species (ROS) generation in vitro and in vivo, caused cellular DNA fragmentation, depolarization of the mitochondrial membrane and cell cycle arrest. Western blotting showed that both PCT and PCT-Cu induced apoptosis. Upregulation of GRP78 in HepG2 cells following treatment with the agents indicated that endoplasmic reticulum (ER) stress occurred. Furthermore calcium release was revealed in this study, suggesting that PCT and PCT-Cu disturbed calcium homeostasis. It was noted that PCT-Cu sensitized thapsigargin‑stimulated calcium release from the ER, which was correlated with the ROS level they induced, implying that the antitumor activity of PCT and PCT-Cu partly stemmed from calcium mobilization, a situation that was reported in few studies. Our findings may significantly contribute to the understanding of the anti‑proliferative effect of the derivatives of thiosemicarbazones along with their antitumor mechanism.

  19. Inhibition of RNA-dependent DNA polymerase of Rous sarcoma virus by thiosemicarbazones and several cations.

    PubMed

    Levinson, W; Faras, A; Woodson, B; Jackson, J; Bishop, J M

    1973-01-01

    The RNA-dependent DNA polymerase of Rous sarcoma virus is inhibited by N-methyl isatin beta-thiosemicarbazone and by thiosemicarbazide, but not by semicarbazide. These inhibitors also inactivate, upon contact with the virion, the transforming ability of Rous sarcoma virus. Sulfhydryl donors, such as 2-mercapto-ethanol, can prevent these effects. The RNA-directed activity of the purified polymerase is inhibited to a greater degree than is the DNA-directed activity. Two cations, Cu(++) and Hg(++), can inhibit RNA-dependent DNA polymerase and inactivate the transforming ability of the virus. Synergism between N-methyl isatin beta-thiosemicarbazone and Cu(++) occurs, since treatment of the virus with a low dose of either N-methyl isatin beta-thiosemicarbazone or Cu(++) has little effect; however, when the two compounds are mixed together, significant inactivation occurs. This observation supports the hypothesis that the antiviral action of thiosemicarbazones is a function of their ability to act as a ligand for metallic ions. Several cations (Ag(+), Co(++), Zn(++), Cd(++), and Ni(++)) significantly inactivate the RNA-dependent DNA polymerase, but have little effect on the transforming ability. In view of this result, the conclusion that the enzyme activity is required for transformation remains open to question.

  20. The heat capacity of solid antimony selenide

    NASA Astrophysics Data System (ADS)

    Pashinkin, A. S.; Malkova, A. S.; Mikhailova, M. S.

    2008-06-01

    The literature data on the heat capacity of solid antimony selenide over the temperature range 53 K- T m were analyzed. The heat capacity of Sb2Se3 was measured from 350 to 600 K on a DSM-2M calorimeter. The experimental data were used to calculate the dependence C p = a + bT + cT -2 and the thermodynamic functions of solid Sb2Se3 over the temperature range 298.15 700 K.

  1. Cobalt and antimony: genotoxicity and carcinogenicity.

    PubMed

    De Boeck, Marlies; Kirsch-Volders, Micheline; Lison, Dominique

    2003-12-10

    The purpose of this review is to summarise the data concerning genotoxicity and carcinogenicity of Co and Sb. Both metals have multiple industrial and/or therapeutical applications, depending on the considered species. Cobalt is used for the production of alloys and hard metal (cemented carbide), diamond polishing, drying agents, pigments and catalysts. Occupational exposure to cobalt may result in adverse health effects in different organs or tissues. Antimony trioxide is primarily used as a flame retardant in rubber, plastics, pigments, adhesives, textiles, and paper. Antimony potassium tartrate has been used worldwide as an anti-shistosomal drug. Pentavalent antimony compounds have been used for the treatment of leishmaniasis. Co(II) ions are genotoxic in vitro and in vivo, and carcinogenic in rodents. Co metal is genotoxic in vitro. Hard metal dust, of which occupational exposure is linked to an increased lung cancer risk, is proven to be genotoxic in vitro and in vivo. Possibly, production of active oxygen species and/or DNA repair inhibition are mechanisms involved. Given the recently provided proof for in vitro and in vivo genotoxic potential of hard metal dust, the mechanistic evidence of elevated production of active oxygen species and the epidemiological data on increased cancer risk, it may be advisable to consider the possibility of a new evaluation by IARC. Both trivalent and pentavalent antimony compounds are generally negative in non-mammalian genotoxicity tests, while mammalian test systems usually give positive results for Sb(III) and negative results for Sb(V) compounds. Assessment of the in vivo potential of Sb2O3 to induce chromosome aberrations (CA) gave conflicting results. Animal carcinogenicity data were concluded sufficient for Sb2O3 by IARC. Human carcinogenicity data is difficult to evaluate given the frequent co-exposure to arsenic. Possible mechanisms of action, including potential to produce active oxygen species and to interfere with

  2. THE CRYSTAL STRUCTURE OF ANTIMONY (III) SULFOBROMIDE, SBSBR,

    DTIC Science & Technology

    ANTIMONY COMPOUNDS, *SULFUR COMPOUNDS, CRYSTAL STRUCTURE , CRYSTAL STRUCTURE , BROMIDES, SYMMETRY(CRYSTALLOGRAPHY), FOURIER ANALYSIS, MOLECULAR STRUCTURE, CRYSTAL LATTICES, CHEMICAL BONDS, X RAY DIFFRACTION.

  3. [Removal of Antimony in Wastewater by Electrochemical Hydride Generation and the Recovery of Antimony].

    PubMed

    Chen, Jing-jing; Zhang, Guo-ping; Li, Hai-xia; Fu, Zhi-ping; Ouyang, Xiao-xue; Wu, Qiong

    2015-04-01

    An electrochemical hydride generation method was developed for the removal of antimony in wastewater. Hydrogen was generated in the electrolysis of water. Hydrogen reacted with Sb and formed stibine, which volatilized from the solution. Then, stibine was heated and decomposed to elemental Sb. Based on these, Sb in wastewater could be removed and recovered. The highest removal of Sb (76.1%) was achieved in acidic solution (pH = 4). The formation of stibine was proven to contribute most significantly (66.2%) to the removal of antimony in the solution, while the electro-deposition and adsorption also made a small contribution. In the treatment, Sb(V) must be pre-reduced to Sb(III) prior to the formation of stibine. Lead, graphite and tungsten were employed as the materials for cathode, and lead electrode was found most suitable for the removal of antimony.

  4. High Temperature Interactions of Antimony with Nickel

    SciTech Connect

    Marina, Olga A.; Pederson, Larry R.

    2012-07-01

    In this chapter, the surface and bulk interactions of antimony with the Ni-based anodes in solid oxide fuel cells (SOFC) will be discussed. High fuel flexibility is a significant advantage of SOFCs, allowing the direct use of fossil and bio fuels without a hydrogen separation unit. Synthesis gas derived from coal and biomass consists of a mixture of hydrogen, carbon monoxide, carbon dioxide, and steam, but finite amounts of tars and trace impurities such as S, Se, P, As, Sb, Cd, Pb, Cl, etc, are also always present. While synthesis gas is commonly treated with a series of chemical processes and scrubbers to remove the impurities, complete purification is not economical. Antimony is widely distributed in coals. During coal gasification antimony is volatilized, such that contact with the SOFC anodes and other SOFC parts, e.g., interconnect, current collecting wires, fuel gas supplying tubing, is most likely. This chapter addresses the following topics: high temperature Ni - Sb interactions; alteration phase, Ni3Sb, Ni5Sb2, NiSb, formation; thermochemical modeling; impact of Sb on the electrocatalytic activity of Ni toward the fuel oxidation and the presence of other impurities (sulfur, in particular); converted anode structural instability during long-term SOFC operation; comparison with nickel heterogeneous catalysts.

  5. Comparing polyaluminum chloride and ferric chloride for antimony removal.

    PubMed

    Kang, Meea; Kamei, Tasuku; Magara, Yasumoto

    2003-10-01

    Antimony has been one of the contaminants required to be regulated, however, only limited information has been collected to date regarding antimony removal by polyaluminium chloride (PACl) and ferric chloride (FC). Accordingly, the possible use of coagulation by PACl or FC for antimony removal was investigated. Jar tests were used to determine the effects of solution pH, coagulant dosage, and pre-chlorination on the removal of various antimony species. Although high-efficiency antimony removal by aluminum coagulation has been expected because antimony is similar to arsenic in that both antimony and arsenic are a kind of metalloid in group V of the periodic chart, this study indicated: (1) removal density (arsenic or antimony removed per mg coagulant) for antimony by PACl was about one forty-fifth as low as observed for As(V); (2) although the removal of both Sb(III) and Sb(V) by coagulation with FC was much higher than that of PACl, a high coagulant dose of 10.5mg of FeL(-1) at optimal pH of 5.0 was still not sufficient to meet the standard antimony level of 2 microg as SbL(-1) for drinking water when around 6 microg as SbL(-1) were initially present. Consequently, investigation of a more appropriate treatment process is necessary to develop economical Sb reduction; (3) although previous studies concluded that As(V) is more effectively removed than As(III), this study showed that the removal of Sb(III) by coagulation with FC was much more pronounced than that of Sb(V); (4) oxidation of Sb(III) with chlorine decreased the ability of FC to remove antimony. Accordingly, natural water containing Sb(III) under anoxic condition should be coagulated without pre-oxidation.

  6. Thiosemicarbazone modification of 3-acetyl coumarin inhibits Aβ peptide aggregation and protect against Aβ-induced cytotoxicity.

    PubMed

    Ranade, Dnyanesh S; Bapat, Archika M; Ramteke, Shefali N; Joshi, Bimba N; Roussel, Pascal; Tomas, Alain; Deschamps, Patrick; Kulkarni, Prasad P

    2016-10-04

    Aggregation of amyloid β peptide (Aβ) is an important event in the progression of Alzheimer's disease. Therefore, among the available therapeutic approaches to fight with disease, inhibition of Aβ aggregation is widely studied and one of the promising approach for the development of treatments for Alzheimer's disease. Thiosemicarbazone compounds are known for their variety of biological activities. However, the potential of thiosemicarbazone compounds towards inhibition of Aβ peptide aggregation and the subsequent toxicity is little explored. Herein, we report synthesis and x-ray crystal structure of novel compound 3-acetyl coumarin thiosemicarbazone and its efficacy toward inhibition of Aβ(1-42) peptide aggregation. Our results indicate that 3-acetyl coumarin thiosemicarbazone inhibits Aβ(1-42) peptide aggregation up to 80% compared to the parent 3-acetyl coumarin which inhibits 52%. Further, 3-acetyl coumarin thiosemicarbazone provides neuroprotection against Aβ-induced cytotoxicity in SH-SY5Y cell line. These findings indicate that thiosemicarbazone modification renders 3-acetyl coumarin neuroprotective properties.

  7. 21 CFR 862.3110 - Antimony test system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... antimony, a heavy metal, in urine, blood, vomitus, and stomach contents. Measurements obtained by this... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Antimony test system. 862.3110 Section 862.3110 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES...

  8. 21 CFR 862.3110 - Antimony test system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... antimony, a heavy metal, in urine, blood, vomitus, and stomach contents. Measurements obtained by this... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Antimony test system. 862.3110 Section 862.3110 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES...

  9. 21 CFR 862.3110 - Antimony test system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... antimony, a heavy metal, in urine, blood, vomitus, and stomach contents. Measurements obtained by this... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Antimony test system. 862.3110 Section 862.3110 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES...

  10. 21 CFR 862.3110 - Antimony test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... antimony, a heavy metal, in urine, blood, vomitus, and stomach contents. Measurements obtained by this... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Antimony test system. 862.3110 Section 862.3110 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES...

  11. 21 CFR 862.3110 - Antimony test system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... antimony, a heavy metal, in urine, blood, vomitus, and stomach contents. Measurements obtained by this... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Antimony test system. 862.3110 Section 862.3110 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES...

  12. The exposure to and health effects of antimony

    PubMed Central

    Cooper, Ross G.; Harrison, Adrian P.

    2009-01-01

    Context: This minireview describes the health effects of antimony exposure in the workplace and the environment. Aim: To collate information on the consequences of occupational and environmental exposure to antimony on physiological function and well-being. Methods: The criteria used in the current minireview for selecting articles were adopted from proposed criteria in The International Classification of Functioning, Disability and Health. Articles were classified from an acute and chronic exposure and toxicity thrust. Results: The proportion of utilised and non-utilised articles was tabulated. Antimony toxicity is dependent on the exposure dose, duration, route (breathing, eating, drinking, or skin contact), other chemical exposures, age, sex, nutritional status, family traits, life style, and state of health. Chronic exposure to antimony in the air at levels of 9 mg/m3 may exacerbate irritation of the eyes, skin, and lungs. Long-term inhalation of antimony can potentiate pneumoconiosis, altered electrocardiograms, stomach pain, diarrhea, vomiting, and stomach ulcers, results which were confirmed in laboratory animals. Although there were investigations of the effect of antimony in sudden infant death syndrome, current findings suggest no link. Antimony trioxide exposure is predominant in smelters. Mining and exposure via glass working, soldering, and brazing are also important. Conclusion: Antimony has some useful but undoubtedly harmful effects on health and well-being and measures need to be taken to prevent hazardous exposure of the like. Its biological monitoring in the workplace is essential. PMID:20165605

  13. Preparation of zinc sulfide nanocrystallites from single-molecule precursors

    NASA Astrophysics Data System (ADS)

    Palve, Anil M.; Garje, Shivram S.

    2011-07-01

    Zinc sulfide nanocrystallites were prepared using Zinc(II) thiosemicarbazone complexes of the types Zn(L) 2 and ZnCl 2(LH) 2 (where, LH=thiosemicarbazones of cinnamaldehyde, 4-chlorobenzaldehyde, indol-3-carboxaldehyde and thiophene-2-carboxaldehyde) as single source precursors by solvothermal decomposition in ethylene glycol and ethylene diamine in few cases. The materials were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction, energy dispersive X-ray analysis and UV-vis and IR spectroscopy. Solvothermal decomposition in ethylene glycol resulted in the formation of hexagonal ZnS (JCPDS: 36-1450) as evident from the XRD patterns. However, XRD shows formation of hybrid material, ZnS 0.5EN in case of solvothermal decomposition in ethylenediamine. Infrared spectra authenticate the capping of ethylene glycol and ethylenediamine on ZnS and ZnS 0.5EN, respectively. TEM images showed formation of spherical nanoparticles for the materials obtained from ethylene glycol, whereas plate-like morphology is observed in case of materials obtained from ethylene diamine. The blue shift of absorption bands compared to bands of bulk materials in the UV-vis spectra supports the formation of smaller particles.

  14. Cytotoxic and antimicrobial effects of indium(iii) complexes with 2-acetylpyridine-derived thiosemicarbazones.

    PubMed

    Oliveira, Alexandre A; Perdigão, Gabriele M C; Rodrigues, Luana E; da Silva, Jeferson G; Souza-Fagundes, Elaine M; Takahashi, Jacqueline A; Rocha, Willian R; Beraldo, Heloisa

    2017-01-17

    Complexes [In(2Ac4oClPh)Cl2(MeOH)] (1), [In(2Ac4pFPh)Cl2(MeOH)] (2), [In(2Ac4pClPh)Cl2(MeOH)] (3) and [In(2Ac4pIPh)Cl2(MeOH)] (4) were obtained with N(4)-ortho-chlorophenyl-2-acetylpyridine thiosemicarbazone (H2Ac4oClPh), N(4)-para-fluorophenyl-2-acetylpyridine thiosemicarbazone (H2Ac4pFPh), N(4)-para-chlorophenyl-2-acetylpyridine thiosemicarbazone (H2Ac4pClPh) and N(4)-para-iodophenyl-2-acetylpyridine thiosemicarbazone (H2Ac4pIPh). Theoretical studies suggested that the coordinated methanol molecule can be easily replaced by DMSO used in the preparation of stock solutions, with the formation of [In(L)Cl2(DMSO)] (HL = thiosemicarbazonate ligand), and that the replacement of DMSO by water is unfavorable. However, for all complexes the displacement of one or two chloride ligands by water in aqueous solution is extremely favorable. The cytotoxic activity of the compounds was evaluated against HL-60, Jurkat and THP-1 leukemia and against MDA-MB-231 and HCT-116 solid tumor cell lines, as well as against Vero non-malignant cells. The cytotoxicity and selectivity indexes (SI) increased in several cases for the indium(iii) complexes in comparison with the free thiosemicarbazones. The antimicrobial activity of the compounds was investigated against Candida albicans, Candida dubliniensis, Candida lusitaniae and Candida parapsilosis. In many cases complexation resulted in a substantial increase of the antifungal activity. Complexes (1-4) were revealed to be very active against C. lusitaniae and C. dubliniensis. Structure-activity relationship (SAR) studies were carried out to identify the physico-chemical properties that might be involved in the antifungal action, as well as in the cytotoxic effect of the compounds against HL-60 cells. In both cases, correlations between the bioactivity and physico-chemical properties did not appreciably change when the chloride ligands in [In(L)Cl2(DMSO)] were replaced by water molecules, suggesting [In(L)Cl(H2O)(DMSO)](+) or [In(L)(H2O)2

  15. Synthesis and Antiproliferative Activity of Steroidal Thiosemicarbazone Platinum (Pt(II)) Complexes

    PubMed Central

    Huang, Yanmin; Kong, Erbin; Gan, Chunfang; Liu, Zhiping; Lin, Qifu; Cui, Jianguo

    2015-01-01

    Steroidal compounds exhibit particular physiological activities. In this paper, some steroidal thiosemicarbazones platinum (Pt(II)) complexes were synthesized by the condensation of steroidal ketones with thiosemicarbazide using estrone, chenodeoxycholic acid, and 7-deoxycholic acid as starting materials and complexation of steroidal thiosesemicarbazones with Pt(II). The complexes were characterized by IR, NMR, and MS, and their antiproliferative activities were evaluated. The results showed that some steroidal thiosemicarbazones platinum (Pt(II)) complexes displayed moderate cytotoxicity to HeLa and Bel-7404 cells. Thereinto, complex 6 showed an excellent inhibited selectivity to HeLa cells with an IC50 value of 9.2 μM and SI value of 21.7. At the same time, all compounds were almost inactive to HEK293T (normal kidney epithelial cells). The information obtained from the studies may be useful for the design of novel chemotherapeutic drugs. PMID:26635511

  16. Synthesis, physicochemical properties, and in vitro antibacterial screening of palladium(II) complexes derived from thiosemicarbazone.

    PubMed

    Azam, Mohammad; Warad, Ismail; Al-Resayes, Saud I; Siddiqui, M Rafiq; Oves, M

    2013-06-01

    A new series of PdII complexes derived from thiosemicarbazone has been synthesized. The synthesized PdII complexes have been characterized on the basis of elemental analyses, FT-IR, ¹H- and ¹³C-NMR, UV/VIS, and thermal studies. A square-planar geometry has been assigned around PdII ions on the basis of results obtained from UV/VIS studies. The thiosemicarbazone ligand and its PdII complexes have been screened against Gram-positive (Bacillus subtilis and Staphylococcus aureus) and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria in vitro as growth-inhibiting agents, and the results revealed significant antibacterial activities.

  17. Antimony ore in the Fairbanks district, Alaska

    USGS Publications Warehouse

    Killeen, Pemberton Lewis; Mertie, John B.

    1951-01-01

    Antimony-bearing ores in the Fairbanks district, Alaska, are found principally in two areas, the extremities of which are at points 10 miles west and 23 miles northeast of Fairbanks; and one of two minor areas lies along this same trend 30 miles farther to the northeast. These areas are probably only local manifestations of mineralization that affected a much broader area and formed antimony-bearing deposits in neighboring districts, the closest of which is 50 miles away. The ores were exposed largely as a result of lode gold mining, but at two periods in the past, high prices for antimony ore warranted an independent production and about 2500 tons of stibnite ore was shipped. The sulfide deposits occupy the same fractures along which a gold-quartz mineralization of greater economic importance occurred; and both are probably genetically related to igneous rocks which intrude the schistose country rock. The sulfide is in part contemporaneous with some late-stage quartz in which it occurs as disseminated crystals; and in part the latest filling in the mineralized zones where it forms kidney-shaped masses of essentially solid sulfide. One extremely long mass must have contained nearly 100 tons of ore, but the average of the larger kidneys is closer to several tons. Much of the ore is stibnite, with quartz as a minor impurity, and assays show the tenor to vary from 40 to 65 percent antimony. Sulphantimonites are less abundant but likewise occur as disseminated crystals and as kidney-shaped bodies. Antimony oxides appear on the weathered surface and along fractures within the sulfide ore. Deposits containing either stibnite or sulphantimonite are known at more than 50 localities, but only eighteen have produced ore and the bulk of this came from the mines. The geology of the deposit, and the nature, extent, and period of the workings are covered in the detailed descriptions of individual occurrences. Several geologic and economic factors, which greatly affect

  18. Antimony quantification in Leishmania by electrothermal atomic absorption spectroscopy.

    PubMed

    Roberts, W L; Rainey, P M

    1993-05-15

    Tri- and pentavalent antimony were quantified in Leishmania mexicana pifanoi amastigotes and promastigotes by atomic absorption spectroscopy with electrothermal atomization. Leishmania grown in axenic culture were treated with either potassium antimony tartrate [Sb(III)] or sodium stibogluconate [Sb(V)]. The parasites were collected, digested with nitric acid, and subjected to atomic absorption spectroscopy. The method was linear from 0 to 7 ng of antimony. The interassay coefficients of variation were 9.6 and 5.7% (N = 5) for 0.52 and 3.7-ng samples of leishmanial antimony, respectively. The limit of detection was 95 pg of antimony. The assay was used to characterize Sb(III) and Sb(V) influx and efflux kinetics. Influx rates were determined at antimony concentrations that produced a 50% inhibition of growth (IC50). The influx rates of Sb(V) into amastigotes and promastigotes were 4.8 and 12 pg/million cells/h, respectively, at 200 micrograms antimony/ml. The influx rate of Sb(III) into amastigotes was 41 pg/million cells/h at 20 micrograms antimony/ml. Influx of Sb(III) into promastigotes at 1 microgram antimony/ml was rapid and reached a plateau of 175 pg/million cells in 2 h. Efflux of Sb(III) and Sb(V) from amastigotes and promastigotes exhibited biphasic kinetics. The initial (alpha) half-life of Sb(V) efflux was less than 4 min and that of Sb(III) was 1-2 h. The apparent terminal (beta) half-lives ranged from 7 to 14 h.

  19. In vitro antiparasitic activity of new thiosemicarbazones in strains of Trypanosoma cruzi.

    PubMed

    Moreno-Rodríguez, Adriana; Salazar-Schettino, Paz María; Bautista, Juan Luis; Hernández-Luis, Francisco; Torrens, Hugo; Guevara-Gómez, Yolanda; Pina-Canseco, Socorro; Torres, Martha Bucio; Cabrera-Bravo, Margarita; Martinez, Cesar Mendoza; Pérez-Campos, Eduardo

    2014-11-24

    In this study thiosemicarbazones derivatives of 5-[(trifluoromethyl)phenylthio]-2-furaldehyde were synthesized and evaluated in terms of their efficiency in challenging the growth of epimastigote forms of Trypanosoma cruzi, the etiological agent of Chagas' disease. A number of compounds were synthesized from 5-bromo-2-furfuraldehyde using nucleophilic aromatic substitution, with a series of trifluoromethyl thiolates, followed by condensation reactions with thiosemicarbazide. Their molecular structures were determined by (1)H, (13)C and (19)F NMR, MS and IR spectroscopy. When tested with T. cruzi, they showed a stronger reaction, similar to nifurtimox and benznidazole, with the 5-[nitro-4-(trifluoromethyl)phenyltio]-2-furaldehyde thiosemicarbazone (compound 4) showing the highest antiparasitic activity. This improved activity may be explained due to the nitro group present in the molecule, which potentiates its activity. The thiosemicarbazone derivatives in this study showed no apoptosis in platelets or monocytes, nor did they induce platelet activation. The trypanocidal activity of these substances represents a good starting point for a medicinal chemistry program aimed at therapy for Chagas' disease.

  20. Organotin(IV) complexes of 2-pyridineformamide-derived thiosemicarbazones: antimicrobial and cytotoxic effects.

    PubMed

    Mendes, Isolda C; Moreira, Juliana P; Ardisson, José D; Santos, Raquel Gouvea Dos; da Silva, Paulo Roberto O; Garcia, Isabel; Castiñeiras, Alfonso; Beraldo, Heloisa

    2008-07-01

    Reaction of n-butyltin trichloride [(n-Bu)SnCl(3)] with 2-pyridineformamide thiosemicarbazone (H2Am4DH) and its N(4)-methyl (H2Am4Me) and N(4)-ethyl (H2Am4Et) derivatives gave [(n-Bu)Sn(2Am4DH)Cl(2)] (1), [(n-Bu)Sn(2Am4Me)Cl(2)] (2), and [(n-Bu)Sn(2Am4Et)Cl(2)] (3). Thiosemicarbazones as well as their tin complexes are active as antimicrobials against the growth of Candida albicans and Salmonella typhimurium and were highly active against malignant glioblastoma. The cytotoxic activity of complexes 1-3 is similar. Among the studied compounds [(n-Bu)Sn(2Am4DH)Cl(2)] (1) was the most active as antiproliferative (cytostatic) agent. Thiosemicarbazones and their tin(IV) complexes proved to be more potent as cytotoxic agents than cisplatin. All the compounds were able to induce apoptosis.

  1. Complexes of 2-acetyl-gamma-butyrolactone and 2-furancarbaldehyde thiosemicarbazones: antibacterial and antifungal activity.

    PubMed

    Rodríguez-Argüelles, María C; Tourón-Touceda, Patricia; Cao, Roberto; García-Deibe, Ana M; Pelagatti, Paolo; Pelizzi, Corrado; Zani, Franca

    2009-01-01

    Cobalt, nickel, copper and zinc coordination compounds of two thiosemicarbazones with general composition ML(2) (L: monodeprotonated ligand corresponding to 2-acetyl-gamma-butyrolactone thiosemicarbazone, HL(1), and 2-furancarbaldehyde thiosemicarbazone, HL(2)) and also complexes with general composition MCl(2)(HL(2)) were synthesized (except [NiCl(2)(HL(2))] and [Co(L(2))(2)]). The interaction of CuCl(2) with HL(2) gave [CuCl(HL(2))], a copper(I) complex. The ligands and metal complexes were characterized by IR, (1)H and (13)C NMR spectroscopy, and magnetic susceptibility measurements. The crystal structure of [Ni(L(2))(2)]x 2dmso was determined and a trans-square planar coordination of the two kappa(2)-N,S chelate rings forming polymeric strips through H-bonds with dmso was observed. Actually, in all the reported complexes both ligands behaved as kappa(2)-N,S chelates, except in the case of [Co(L(1))(2)] in which HL(1) is tridentate kappa(3)-N,S,O. The antimicrobial properties of all compounds were studied using a wide spectrum of bacterial and fungal strains. The copper complexes of HL(2) were the most active against all strains, including dermatophytes and phytopathogenic fungi. Most of the studied compounds, especially [Cu(L(1))(2)], presented good activity against Haemophilus influenzae, a very harmful bacterium to humans.

  2. Tissue distribution of residual antimony in rats treated with multiple doses of meglumine antimoniate

    PubMed Central

    Coelho, Deise Riba; Miranda, Elaine Silva; Saint’Pierre, Tatiana Dillenburg; Paumgartten, Francisco José Roma

    2014-01-01

    Meglumine antimoniate (MA) and sodium stibogluconate are pentavalent antimony (SbV) drugs used since the mid-1940s. Notwithstanding the fact that they are first-choice drugs for the treatment of leishmaniases, there are gaps in our knowledge of their toxicological profile, mode of action and kinetics. Little is known about the distribution of antimony in tissues after SbV administration. In this study, we evaluated the Sb content of tissues from male rats 24 h and three weeks after a 21-day course of treatment with MA (300 mg SbV/kg body wt/d, subcutaneous). Sb concentrations in the blood and organs were determined by inductively coupled plasma-mass spectrometry. In rats, as with in humans, the Sb blood levels after MA dosing can be described by a two-compartment model with a fast (t1/2 = 0.6 h) and a slow (t1/2 >> 24 h) elimination phase. The spleen was the organ that accumulated the highest amount of Sb, while bone and thyroid ranked second in descending order of tissues according to Sb levels (spleen >> bone, thyroid, kidneys > liver, epididymis, lungs, adrenals > prostate > thymus, pancreas, heart, small intestines > skeletal muscle, testes, stomach > brain). The pathophysiological consequences of Sb accumulation in the thyroid and Sb speciation in the liver, thyroid, spleen and bone warrant further studies. PMID:25075781

  3. Biogeochemistry of arsenic and antimony in the North Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Cutter, Gregory A.; Cutter, Lynda S.

    2006-05-01

    The biogeochemical cycles of the metalloid elements arsenic and antimony were examined along a 15,000 km surface water transect and at 9 vertical profile stations in the western North Pacific Ocean as part of the 2002 IOC Contaminant Baseline Survey. Results show that the speciation of dissolved arsenic (As III, As V, and methylated As) was subtly controlled by the arsenate (AsV)/phosphate ratio. An additional fraction of presumed organic arsenic previously reported in coastal waters was also present (˜15% of the total As) in oceanic surface waters. Dissolved inorganic antimony displayed mildly scavenged behavior that was confirmed by correlations with aluminum, but atmospheric inputs that may be anthropogenic in origin also affected its concentrations. Monomethyl antimony, the predominant organic form of the element, behaved almost conservatively throughout the water column, radically changing the known biogeochemical cycle of antimony.

  4. Comparative trials of antimonial drugs in urinary schistosomiasis

    PubMed Central

    Davis, A.

    1968-01-01

    Chemotherapeutic trials in urinary schistosomiasis are described and discussed. Their design and conduct were based on recommended statistical techniques, now generally accepted as the most appropriate approach to the assessment of antischistosomal drugs. Randomization produced comparable host groups in whom multiple parasitic infection and radiological urinary tract damage were common. Treatment was with one of three antimonial compounds given at equivalent metallic dosage daily. Antimony sodium tartrate (AST) and antimony dimercaptosuccinate (TWSb) were equally efficient curatively but both produced many side-effects. Sodium antimonylgluconate (TSAG) was four-fifths as effective but tolerance was superior. Estimations of urinary antimony excretion showed that tissue retention of the metal was related to cure-rates and side-effects. It was concluded that none of the drugs were suitable for mass chemotherapy. More new non-toxic schistosomicides are urgently needed and for their assessment, the setting-up of multicentre trials, following international agreement on technical methods, is suggested. PMID:5302298

  5. Characterization of the Antimonial Antileishmanial Agent Meglumine Antimonate (Glucantime)

    PubMed Central

    Roberts, William L.; McMurray, Walter J.; Rainey, Petrie M.

    1998-01-01

    Meglumine antimonate (Glucantime), a drug of choice for the treatment of leishmaniasis, is produced by the reaction of pentavalent antimony with N-methyl-d-glucamine, a carbohydrate derivative. We investigated the structure and composition of meglumine antimonate, which remain poorly understood, despite 50 years of use. Measurement of the antimony content of meglumine antimonate powder indicated a 1:1.37 molar ratio of antimony to N-methyl-d-glucamine. Osmolality measurements performed with meglumine antimonate solutions demonstrated an average of 1.43 antimony atoms per molecule of meglumine antimonate. The osmolality of a 1:10 dilution of stock meglumine antimonate increased by 45% over 8 days, suggesting hydrolysis to less complex species. A comparison of the proton nuclear magnetic resonance spectra of N-methyl-d-glucamine and meglumine antimonate revealed an increase in complexity in the latter but with all of the resonances of the former still being evident, consistent with the presence of coordination complexes between antimony and each of the N-methyl-d-glucamine hydroxyls. Fast atom bombardment and electrospray ionization mass spectrometry coupled with several derivatization procedures provided evidence that up to four N-methyl-d-glucamine hydroxyls are coordinated with each antimony. A series of oligomers were observed. The major moiety has a molecular mass of 507 atomic mass units and consists of NMG-Sb-NMG, where Sb represents antimony and NMG represents N-methyl-d-glucamine. Additional species containing up to four antimony atoms and five N-methyl-d-glucamine moieties and corresponding to the general form (NMG-Sb)n-NMG are also present. These results suggest that this agent is a complex mixture that exists in equilibrium in aqueous solution. PMID:9593130

  6. Synthesis, characterization and binding affinities of rhenium(I) thiosemicarbazone complexes for the estrogen receptor (α/β).

    PubMed

    Núñez-Montenegro, Ara; Carballo, Rosa; Vázquez-López, Ezequiel M

    2014-11-01

    The binding affinities towards estrogen receptors (ERs) α and β of a set of thiosemicarbazone ligands (HL(n)) and their rhenium(I) carbonyl complexes [ReX(HL(n))(CO)3] (X=Cl, Br) were determined by a competitive standard radiometric assay with [(3)H]-estradiol. The ability of the coordinated thiosemicarbazone ligands to undergo deprotonation and the lability of the ReX bond were used as a synthetic strategy to obtain [Re(hpy)(L(n))(CO)3] (hpy=3- or 4-hydroxypyridine). The inclusion of the additional hpy ligand endows the new thiosemicarbazonate complexes with an improved affinity towards the estrogen receptors and, consequently, the values of the inhibition constant (Ki) could be determined for some of them. In general, the values of Ki for both ER subtypes suggest an appreciable selectivity towards ERα.

  7. Strong effect of copper(II) coordination on antiproliferative activity of thiosemicarbazone-piperazine and thiosemicarbazone-morpholine hybrids.

    PubMed

    Bacher, Felix; Dömötör, Orsolya; Chugunova, Anastasia; Nagy, Nóra V; Filipović, Lana; Radulović, Siniša; Enyedy, Éva A; Arion, Vladimir B

    2015-05-21

    In this study, 2-formylpyridine thiosemicarbazones and three different heterocyclic pharmacophores were combined to prepare thiosemicarbazone–piperazine mPip-FTSC (HL1) and mPip-dm-FTSC (HL2), thiosemicarbazone–morpholine Morph-FTSC (HL3) and Morph-dm-FTSC (HL4), thiosemicarbazone–methylpyrrole-2-carboxylate hybrids mPyrr-FTSC (HL5) and mPyrr-dm-FTSC (HL6) as well as their copper(II) complexes [CuCl(mPipH-FTSC-H)]Cl (1 + H)Cl, [CuCl(mPipH-dm-FTSC-H)]Cl (2 + H)Cl, [CuCl(Morph-FTSC-H)] (3), [CuCl(Morph-dm-FTSC-H)] (4), [CuCl(mPyrr-FTSC-H)(H2O)] (5) and [CuCl(mPyrr-dm-FTSC-H)(H2O)] (6). The substances were characterized by elemental analysis, one- and two-dimensional NMR spectroscopy (HL1–HL6), ESI mass spectrometry, IR and UV–vis spectroscopy and single crystal X-ray diffraction (1–5). All compounds were prepared in an effort to generate potential antitumor agents with an improved therapeutic index. In addition, the effect of structural alterations with organic hybrids on aqueous solubility and copper(II) coordination ability was investigated. Complexation of ligands HL2 and HL4 with copper(II) was studied in aqueous solution by pH-potentiometry, UV–vis spectrophotometry and EPR spectroscopy. Proton dissociation processes of HL2 and HL4 were also characterized in detail and microscopic constants for the Z/E isomers were determined. While the hybrids HL5, HL6 and their copper(II) complexes 5 and 6 proved to be insoluble in aqueous solution, precluding antiproliferative activity studies, the thiosemicarbazone–piperazine and thiosemicarbazone–morpholine hybrids HL1–HL4, as well as copper(II) complexes 1–4 were soluble in water enabling cytotoxicity assays. Interestingly, the metal-free hybrids showed very low or even a lack of cytotoxicity (IC50 values > 300 μM) in two human cancer cell lines HeLa (cervical carcinoma) and A549 (alveolar basal adenocarcinoma), whereas their copper(II) complexes were cytotoxic showing IC50 values from 25.5 to 65.1

  8. Synthesis, Spectroscopic and Toxicity Studies of Titanocene Chelates of Isatin-3-Thiosemicarbazones

    PubMed Central

    Vatsa, Garima; Pandey, O. P.; Sengupta, S. K.

    2005-01-01

    The reactions of bis(cyclopentadienyl)titanium(IV) dichloride with a new class of thiosemicarbazone (LH2), derived by condensing isatin with different N(4)-substituted thiosemicarbazides, have been studied and products of type [Cp2Ti(L)] have been isolated. On the basis of various physico-chemical and spectral studies, five coordinate structures have been assigned to these derivatives. Toxicity studies of titanocene complexes at tbur different concentrations have been carried out against snail Lymnaea acuminata. The effect of most potent compounds on the activity of acetylcholinesterase enzyme, which inhibits the activity of enzyme, possibly by the formation of enzyme-inhibitor complex, was also studied. PMID:18365096

  9. Laser resonance ionization spectroscopy of antimony

    NASA Astrophysics Data System (ADS)

    Li, R.; Lassen, J.; Ruczkowski, J.; Teigelhöfer, A.; Bricault, P.

    2017-02-01

    The resonant ionization laser ion source is an element selective, efficient and versatile ion source to generate radioactive ion beams at on-line mass separator facilities. For some elements with complex atomic structures and incomplete spectroscopic data, laser spectroscopic investigations are required for ionization scheme development. Laser resonance ionization spectroscopy using Ti:Sa lasers has been performed on antimony (Sb) at TRIUMF's off-line laser ion source test stand. Laser light of 230.217 nm (vacuum wavelength) as the first excitation step and light from a frequency-doubled Nd:YVO4 laser (532 nm) as the nonresonant ionization step allowed to search for suitable second excitation steps by continuous wavelength scans from 720 nm to 920 nm across the wavelength tuning range of a grating-tuned Ti:Sa laser. Upon the identification of efficient SES, the third excitation steps for resonance ionization were investigated by laser scans across Rydberg states, the ionization potential and autoionizing states. One Rydberg state and six AI states were found to be well suitable for efficient resonance ionization.

  10. [Antimony and other heavy metals in metallic kitchen ware].

    PubMed

    Ishiwata, H; Sugita, T; Yoshihira, K

    1989-01-01

    The antimony in metallic kitchen ware was determined. The content of this element in metals used for the production or repairing of utensils, containers and packaging which come in contact with foods is regulated and should be less than 5% in under the Japanese Food Sanitation Law. In eight metallic samples, antimony was detected in solder used for the production of a can for green tea and an eggbeater. The contents were 1.30% in the former and 1.90% in the latter. No antimony was detected in solder used for a cookie cutter. A sample of solder used for electric work, not for food utensils, contained 0.81% of antimony. In other metallic utensils which come in contact with food such as aluminum foil, a brass spoon, a stainless steel fork, a wire netting, and an iron rock for vegetable color stabilizing, antimony was not detected at a 0.05% detection limit. A qualitative test using rhodamine B also showed positive results in only three solder samples. Lead concentrations in solder used for the kitchen ware were from 39.3 to 51.3%. These concentrations were higher than the limit (20%) of lead content by the Law. No cadmium was detected in any samples.

  11. Novel heterocyclic thiosemicarbazones derivatives as colorimetric and "turn on" fluorescent sensors for fluoride anion sensing employing hydrogen bonding.

    PubMed

    Ashok Kumar, S L; Saravana Kumar, M; Sreeja, P B; Sreekanth, A

    2013-09-01

    Two novel heterocyclic thiosemicarbazone derivatives have been synthesized, and characterized, by means of spectroscopic and single crystal X-ray diffraction methods. Their chromophoric-fluorogenic response towards anions in competing solvent dimethyl sulfoxide (DMSO) was studied. The receptor shows selective recognition towards fluoride anion. The binding affinity of the receptors with fluoride anion was calculated using UV-visible and fluorescence spectroscopic techniques.

  12. Coordination to gallium(III) strongly enhances the potency of 2-pyridineformamide thiosemicarbazones against Cryptococcus opportunistic fungi.

    PubMed

    Bastos, Thaíssa de Oliveira; Soares, Betânia Maria; Cisalpino, Patrícia Silva; Mendes, Isolda Castro; dos Santos, Raquel Gouvea; Beraldo, Heloisa

    2010-09-20

    A family of 2-pyridineformamide-derived thiosemicarbazones and their gallium(III) complexes were tested against several isolates of pathogenic Cryptococcus strains. On complexation the antifungal activity significantly increases, suggesting coordination to gallium(III) to be an interesting strategy of antifungal dose reduction.

  13. 40 CFR 440.90 - Applicability; description of the antimony ore subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... antimony ore subcategory. 440.90 Section 440.90 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Antimony Ore Subcategory § 440.90 Applicability; description of the antimony ore subcategory. The provisions of...

  14. Possible Links between Sickle Cell Crisis and Pentavalent Antimony

    PubMed Central

    Garcerant, Daniel; Rubiano, Luisa; Blanco, Victor; Martinez, Javier; Baker, Nancy C.; Craft, Noah

    2012-01-01

    For over 60 years, pentavalent antimony (Sbv) has been the first-line treatment of leishmaniasis. Sickle cell anemia is a disease caused by a defect in red blood cells, which among other things can cause vasooclusive crisis. We report the case of a 6-year-old child with leishmaniasis who during treatment with meglumine antimoniate developed a sickle cell crisis (SCC). No previous reports describing the relationship between antimonial drugs and sickle cell disease were found. Reviews of both the pathophysiology of SCC and the mechanism of action of Sbv revealed that a common pathway (glutathione) may have resulted in the SCC. ChemoText, a novel database created to predict chemical-protein-disease interactions, was used to perform a more expansive and systematic review that was able to support the association between glutathione, Sbv, and SCC. Although suggestive evidence to support the hypothesis, additional research at the bench would be needed to prove Sbv caused the SCC. PMID:22665619

  15. Construction of spongy antimony-doped tin oxide/graphene nanocomposites using commercially available products and its excellent electrochemical performance

    NASA Astrophysics Data System (ADS)

    Zhao, Xiaowei; Zhang, Jingwei; Zhang, Jiwei; Gong, Chunhong; Gu, Xiufang; Ma, Zhihua; Zhou, Jingfang; Yu, Laigui; Zhang, Zhijun

    2015-10-01

    We construct successfully a porous antimony-doped tin oxide (ATO)/nitrogen-doped graphene 3-dimensional (3D) frameworks (denoted as ATO/NG/TEPA; TEPA refers to tetraethylenepentamine) by a one-pot hydrothermal process, with which TEPA aqueous solution is adopted to easily re-disperse commercial ATO precursor forming a transparent hydrosol. The results show that TEPA plays a key role in the construction of ATO/NG/TEPA, not only acting as a peptization reagent to re-disperse ATO precursor nanoparticles, and as a linker to combine ATO with graphene sheets. The as-fabricated ATO/NG/TEPA hybrid as the negative electrode of lithium ion batteries exhibits excellent lithium storage capacity and cycling stability. With the advantage of easily re-dispersing commercial ATO, the present synthetic route may be put into use for the large-scale production of the titled nanocomposites as the anode material of lithium ion batteries.

  16. Synthesis and Characterization of New Palladium(II) Thiosemicarbazone Complexes and Their Cytotoxic Activity against Various Human Tumor Cell Lines

    PubMed Central

    Hernández, Wilfredo; Paz, Juan; Carrasco, Fernando; Spodine, Evgenia; Manzur, Jorge; Sieler, Joachim; Blaurock, Steffen; Beyer, Lothar

    2013-01-01

    The palladium(II) bis-chelate complexes of the type [Pd(TSC1-5)2] (6–10), with their corresponding ligands 4-phenyl-1-(acetone)-thiosemicarbazone, HTSC1 (1), 4-phenyl-1-(2′-chloro-benzaldehyde)-thiosemicarbazone, HTSC2 (2), 4-phenyl-1-(3′-hydroxy-benzaldehyde)-thiosemicarbazone, HTSC3 (3), 4-phenyl-1-(2′-naphthaldehyde)-thiosemicarbazone, HTSC4 (4), and 4-phenyl-1-(1′-nitro-2′-naphthaldehyde)-thiosemicarbazone, HTSC5 (5), were synthesized and characterized by elemental analysis and spectroscopic techniques (IR and 1H- and 13C-NMR). The molecular structure of HTSC3, HTSC4, and [Pd(TSC1)2] (6) have been determined by single crystal X-ray crystallography. Complex 6 shows a square planar geometry with two deprotonated ligands coordinated to PdII through the azomethine nitrogen and thione sulfur atoms in a cis arrangement. The in vitro cytotoxic activity measurements indicate that the palladium(II) complexes (IC50 = 0.01–9.87 μM) exhibited higher antiproliferative activity than their free ligands (IC50 = 23.48–70.86 and >250 μM) against different types of human tumor cell lines. Among all the studied palladium(II) complexes, the [Pd(TSC3)2] (8) complex exhibited high antitumor activity on the DU145 prostate carcinoma and K562 chronic myelogenous leukemia cells, with low values of the inhibitory concentration (0.01 and 0.02 μM, resp.). PMID:24391528

  17. Synthesis and Characterization of New Palladium(II) Thiosemicarbazone Complexes and Their Cytotoxic Activity against Various Human Tumor Cell Lines.

    PubMed

    Hernández, Wilfredo; Paz, Juan; Carrasco, Fernando; Vaisberg, Abraham; Spodine, Evgenia; Manzur, Jorge; Hennig, Lothar; Sieler, Joachim; Blaurock, Steffen; Beyer, Lothar

    2013-01-01

    The palladium(II) bis-chelate complexes of the type [Pd(TSC(1-5))2] (6-10), with their corresponding ligands 4-phenyl-1-(acetone)-thiosemicarbazone, HTSC(1) (1), 4-phenyl-1-(2'-chloro-benzaldehyde)-thiosemicarbazone, HTSC(2) (2), 4-phenyl-1-(3'-hydroxy-benzaldehyde)-thiosemicarbazone, HTSC(3) (3), 4-phenyl-1-(2'-naphthaldehyde)-thiosemicarbazone, HTSC(4) (4), and 4-phenyl-1-(1'-nitro-2'-naphthaldehyde)-thiosemicarbazone, HTSC(5) (5), were synthesized and characterized by elemental analysis and spectroscopic techniques (IR and (1)H- and (13)C-NMR). The molecular structure of HTSC(3), HTSC(4), and [Pd(TSC(1))2] (6) have been determined by single crystal X-ray crystallography. Complex 6 shows a square planar geometry with two deprotonated ligands coordinated to Pd(II) through the azomethine nitrogen and thione sulfur atoms in a cis arrangement. The in vitro cytotoxic activity measurements indicate that the palladium(II) complexes (IC50 = 0.01-9.87 μM) exhibited higher antiproliferative activity than their free ligands (IC50 = 23.48-70.86 and >250 μM) against different types of human tumor cell lines. Among all the studied palladium(II) complexes, the [Pd(TSC(3))2] (8) complex exhibited high antitumor activity on the DU145 prostate carcinoma and K562 chronic myelogenous leukemia cells, with low values of the inhibitory concentration (0.01 and 0.02 μM, resp.).

  18. Biological activity of complexes derived from pyridine-2-carbaldehyde thiosemicarbazone. Structure of.

    PubMed

    García-Tojal, J; García-Orad, A; Díaz, A A; Serra, J L; Urtiaga, M K; Arriortua, M I; Rojo, T

    2001-04-01

    Biological studies on [Fe(L)2](NO3).0.5H2O (1), [Fe(L)2][PF6] (2), [Co(L)2](NCS) (3), [Ni(HL)2]Cl2.3H2O (4) and Cu(L)(NO3) (5), where HL=C7H8N4S, pyridine-2-carbaldehyde thiosemicarbazone, have been carried out. The crystal structure of compound 3 has been solved. It consists of discrete monomeric cationic entities containing cobalt(III) ions in a distorted octahedral environment. The metal ion is bonded to one sulfur and two nitrogen atoms of each thiosemicarbazone molecule. The thiocyanate molecules act as counterions. The copper(II) and iron(III) complexes react with reduced glutathione and 2-mercaptoethanol. The reaction of compound 1 with the above thiols causes the reduction of the metal ion and bis(thiosemicarbazonato)iron(II) species are obtained. The redox activity, and in particular the reaction with cell thiols, seems to be related to the cytotoxicity of these complexes against Friend erithroleukemia cells and melanoma B16F10 cells.

  19. Lanthanum(III) and praseodymium(III) complexes with isatin thiosemicarbazones.

    PubMed

    Rai, Anita; Sengupta, Soumitra K; Pandey, Om P

    2005-09-01

    Ten new lanthanum(III) and praseodymium(III) complexes of the general formula Na[La(L)2H2O] (Ln=La(III) or Pr(III); LH2=thiosemicarbazones) derived from the condensation of isatin with 4-phenyl thiosemicarbazide, 4-(4-chlorophenyl) thiosemicarbazide, 4-(2-nitrophenyl) thiosemicarbazide, 4-(2-bromophenyl) thiosemicarbazide and 4-(2-methylphenyl) thiosemicarbazide, have been synthesized in methanol in presence of sodium hydroxide. The XRD spectra of the complexes were monitored to verify complex formation. The complexes have also been characterized by elemental analysis, molar conductance, electronic absorption and fluorescence, infrared, far infrared, 1H and 13C NMR spectral studies. Thermal studies of these complexes have been carried out in the temperature range 25-800 degrees C using TG, DTG and DTA techniques. All these complexes decompose gradually with the formation of Ln2O3 as the end product. The Judd-ofelt intensity parameter, oscillator strength, transition probability, stimulated emission cross section for different transitions of Pr3+ for 4-phenyl thiosemicarbazones have been calculated.

  20. Vanadium(IV/V) complexes of Triapine and related thiosemicarbazones: Synthesis, solution equilibrium and bioactivity.

    PubMed

    Kowol, Christian R; Nagy, Nóra V; Jakusch, Tamás; Roller, Alexander; Heffeter, Petra; Keppler, Bernhard K; Enyedy, Éva A

    2015-11-01

    The stoichiometry and thermodynamic stability of vanadium(IV/V) complexes of Triapine and two related α(N)-heterocyclic thiosemicarbazones (TSCs) with potential antitumor activity have been determined by pH-potentiometry, EPR and (51)V NMR spectroscopy in 30% (w/w) dimethyl sulfoxide/water solvent mixtures. In all cases, mono-ligand complexes in different protonation states were identified. Dimethylation of the terminal amino group resulted in the formation of vanadium(IV/V) complexes with considerably higher stability. Three of the most stable complexes were also synthesized in solid state and comprehensively characterized. The biological evaluation of the synthesized vanadium complexes in comparison to the metal-free ligands in different human cancer cell lines revealed only minimal influence of the metal ion. Thus, in addition the coordination ability of salicylaldehyde thiosemicarbazone (STSC) to vanadium(IV/V) ions was investigated. The exchange of the pyridine nitrogen of the α(N)-heterocyclic TSCs to a phenolate oxygen in STSC significantly increased the stability of the complexes in solution. Finally, this also resulted in increased cytotoxicity activity of a vanadium(V) complex of STSC compared to the metal-free ligand.

  1. Cytotoxic gallium complexes containing thiosemicarbazones derived from 9-anthraldehyde: Molecular docking with biomolecules

    NASA Astrophysics Data System (ADS)

    Beckford, Floyd A.; Brock, Alyssa; Gonzalez-Sarrías, Antonio; Seeram, Navindra P.

    2016-10-01

    We have synthesized a trio of gallium complexes bearing 9-anthraldehyde thiosemicarbazones. The complexes were assessed for their anticancer activity and their biophysical reactivity was also investigated. The three complexes displayed good cytotoxic profiles against two human colon cancer cell lines, HCT-116 and Caco-2. The IC50 ranged from 4.7 to 44.1 μM with the complex having an unsubstituted amino group on the thiosemicarbazone being the most active. This particular complex also showed a high therapeutic index. All three complexes bind strongly to DNA via intercalation with binding constants ranging from 7.46 × 104 M-1 to 3.25 × 105 M-1. The strength of the binding cannot be directly related to the level of anticancer activity. The complexes also bind strongly to human serum albumin with binding constants on the order of 104-105 M-1 as well. The complexes act as chemical nucleases as evidenced by their ability to cleave pBR322 plasmid DNA. The binding constants along with the cleavage results may suggest that the extent of DNA interaction is not directly correlated with anticancer activity. The results of docking studies with DNA, ribonucleotide reductase and human serum albumin, however showed that the complex with the best biological activity had the largest binding constant to DNA.

  2. Antimony Based III-V Thermophotovoltaic Devices

    SciTech Connect

    CA Wang

    2004-06-09

    Antimony-based III-V thermophotovoltaic (TPV) cells are attractive converters for systems with low radiator temperature around 1100 to 1700 K, since these cells potentially can be spectrally matched to the thermal source. Cells under development include GaSb and the lattice-matched GaInAsSb/GaSb and InPAsSb/InAs quaternary systems. GaSb cell technology is the most mature, owing in part to the relative ease in preparation of the binary alloy compared to quaternary GaInAsSb and InPAsSb alloys. Device performance of 0.7-eV GaSb cells exceeds 90% of the practical limit. GaInAsSb TPV cells have been the primary focus of recent research, and cells with energy gap E{sub g} ranging from {approx}0.6 to 0.49 eV have been demonstrated. Quantum efficiency and fill factor approach theoretical limits. Open-circuit voltage factor is as high as 87% of the practical limit for the higher-E{sub g} cells, but degrades to below 80% with decreasing E{sub g} of the alloy, which might be due to Auger recombination. InPAsSb cells are the least studied, and a cell with E{sub g} = 0.45-eV has extended spectral response out to 4.3 {micro}m. This paper briefly reviews the main contributions that have been made for antimonide-based TPV cells, and suggests additional studies for further performance enhancements.

  3. Antimony recycling in the United States in 2000

    USGS Publications Warehouse

    Carlin Jr., James F.

    2006-01-01

    The importance of recycling has become more obvious as concerns about the environment and import dependence have grown in recent years. When materials are recycled, fewer natural resources are consumed, and less waste products go to landfills or pollute the water and air. This study, one of a series of reports on metals recycling in 2000, discusses the flow of antimony from mining through its uses and disposal with emphasis on recycling. In 2000, the recycling efficiency for antimony was estimated to be 89 percent, and the recycling rate was about 20 percent.

  4. Reductive precipitation of metals photosensitized by tin and antimony porphyrins

    DOEpatents

    Shelnutt, John A.; Gong, Weiliang; Abdelouas, Abdesselam; Lutze, Werner

    2003-09-30

    A method for reducing metals using a tin or antimony porphyrin by forming an aqueous solution of a tin or antimony porphyrin, an electron donor, such as ethylenediaminetetraaceticacid, triethylamine, triethanolamine, and sodium nitrite, and at least one metal compound selected from a uranium-containing compound, a mercury-containing compound, a copper-containing compound, a lead-containing compound, a gold-containing compound, a silver-containing compound, and a platinum-containing compound through irradiating the aqueous solution with light.

  5. [The corrosion behavior of antimony in a Ag-Sn-Cu-Sb amalgam].

    PubMed

    Weiland, M; Borrmann, S; Nossek, H

    1989-01-01

    Specimen of amalgam containing antimony were stored in solutions with different pH and different content of rhodanide until 21 days. The most antimony were solved within 24 hours. After 7 days an increase of the antimony concentration were not observed in physiological pH. An inhibition of corrosion by rhodanide existed only after incubation from 21 days. The quantity of antimony (10-21 micrograms) were analysed by mean of atomic absorption spectroscopy. It represent not a risk for the health. The natural presence of this element in environment and in human body is discussed to the analysed quantity of solved antimony.

  6. On line automated system for the determination of Sb(V), Sb(III), thrimethyl antimony(v) and total antimony in soil employing multisyringe flow injection analysis coupled to HG-AFS.

    PubMed

    Silva Junior, Mario M; Portugal, Lindomar A; Serra, Antonio M; Ferrer, Laura; Cerdà, Victor; Ferreira, Sergio L C

    2017-04-01

    This paper proposes the use of a multisyringe flow injection analysis (MSFIA) system for inorganic antimony speciation analysis, trimethyl antimony(V) and determination of total antimony in soil samples using hydride generation atomic fluorescence spectrometry (HG-AFS). Total antimony has been determined after reduction of antimony(V) to antimony(III) using potassium iodide and ascorbic acid. For determination of total inorganic antimony the sample is percolated in a mini-column containing the Dowex 50W-X8 resin for retention of the organic species of antimony. Antimony(III) is quantified in presence of 8-hydroxyquinoline as masking agent for antimony(V) after an extraction step of the organic antimony species using the also same mini-column. The trimethyl antimony(V) content is found by difference between total antimony and total inorganic antimony. By other hand, antimony(V) is quantified by difference between total inorganic antimony and antimony(III). The analytical determinations were performed using sodium tetrahydroborate as reducing agent. The optimization step was performed using two-level full factorial design and Doehlert matrix involving the factors: hydrochloric acid and sodium tetrahydroborate concentrations and sample flow rate. The optimized experimental conditions allow the antimony determination utilizing the external calibration technique with limits of detection and quantification of 0.9 and 3.1ngg(-1), respectively, and a precision expressed as relative standard deviation of 3.2% for an antimony solution of 5.0µgL(-1). The method accuracy was confirmed by analysis of the soil certified reference material furnished from Sigma-Aldrich RTC. Additionally, addition/recovery tests were performed employing synthetic solutions prepared using trimethyl antimony(V), antimony(III), antimony(V) and five soil samples. The antimony extraction step was performed in a closed system using hydrochloric acid, ultrasonic radiation and controlled temperature. The

  7. Antimony to Cure Visceral Leishmaniasis Unresponsive to Liposomal Amphotericin B.

    PubMed

    Morizot, Gloria; Jouffroy, Romain; Faye, Albert; Chabert, Paul; Belhouari, Katia; Calin, Ruxandra; Charlier, Caroline; Miailhes, Patrick; Siriez, Jean-Yves; Mouri, Oussama; Yera, Hélène; Gilquin, Jacques; Tubiana, Roland; Lanternier, Fanny; Mamzer, Marie-France; Legendre, Christophe; Peyramond, Dominique; Caumes, Eric; Lortholary, Olivier; Buffet, Pierre

    2016-01-01

    We report on 4 patients (1 immunocompetent, 3 immunosuppressed) in whom visceral leishmaniasis had become unresponsive to (or had relapsed after) treatment with appropriate doses of liposomal amphotericin B. Under close follow-up, full courses of pentavalent antimony were administered without life-threatening adverse events and resulted in rapid and sustained clinical and parasitological cure.

  8. Acid-base properties of titanium-antimony oxides catalysts

    SciTech Connect

    Zenkovets, G.A.; Paukshtis, E.A.; Tarasova, D.V.; Yurchenko, E.N.

    1982-06-01

    The acid-base properties of titanium-antimony oxide catalysts were studied by the methods of back titration and ir spectroscopy. The interrelationship between the acid-base and catalytic properties in the oxidative ammonolysis of propylene was discussed. 3 figures, 1 table.

  9. Antimony(V) Adsorption by Variable-Charge Minerals

    DTIC Science & Technology

    2013-10-01

    Sb(OH)6, SO4, and PO4 adsorption by gibbsite , kaolinite , goethite, and birnessite...pKa triple layer surface complexation modeling of Sb(OH)6, SO4, and PO4 adsorption by gibbsite , kaolinite , goethite, and birnessite...Competition Surface Complexation Triple Layer Model Gibbsite Kaolinite Goethite Birnessite xviii Abstract Background. Antimony (Sb) is a

  10. Discovery of palladium, antimony, tellurium, iodine, and xenon isotopes

    SciTech Connect

    Kathawa, J.; Fry, C.; Thoennessen, M.

    2013-01-15

    Currently, thirty-eight palladium, thirty-eight antimony, thirty-nine tellurium, thirty-eight iodine, and forty xenon isotopes have been observed and the discovery of these isotopes is described here. For each isotope a brief synopsis of the first refereed publication, including the production and identification method, is presented.

  11. Antimony tartrate corrosion inhibitive composition for coolant systems

    SciTech Connect

    Payerle, N.E.

    1987-08-11

    An automobile coolant concentrate is described comprising (a) a liquid polyhydric alcohol chosen from the group consisting of ethylene glycol, propylene glycol, diethylene glycol and mixtures thereof, and (b) corrosion inhibitors in a corrosion inhibitory amount with respect to corrosion of lead-containing solders, the corrosion inhibitors comprising (i) an alkali metal antimony tartrate, and (ii) an azole compound.

  12. Influence of Antimony-Halogen Additives on Flame Propagation.

    PubMed

    Babushok, Valeri I; Deglmann, Peter; Krämer, Roland; Linteris, Gregory T

    2017-01-01

    A kinetic model for flame inhibition by antimony-halogen compounds in hydrocarbon flames is developed. Thermodynamic data for the relevant species are assembled from the literature, and calculations are performed for a large set of additional species of Sb-Br-C-H-O system. The main Sb- and Br-containing species in the combustion products and reaction zone are determined using flame equilibrium calculations with a set of possible Sb-Br-C-H-O species, and these are used to develop the species and reactions in a detailed kinetic model for antimony flame inhibition. The complete thermodynamic data set and kinetic mechanism are presented. Laminar burning velocity simulations are used to validate the mechanism against available data in the literature, as well as to explore the relative performance of the antimony-halogen compounds. Further analysis of the premixed flame simulations has unraveled the catalytic radical recombination cycle of antimony. It includes (primarily) the species Sb, SbO, SbO2, and HOSbO, and the reactions: Sb+O+M=SbO+M; Sb+O2+M=SbO2+M; SbO+H=Sb+OH; SbO+O=Sb+O2; SbO+OH+M=HOSbO+M; SbO2+H2O=HOSbO+OH; HOSbO+H=SbO+H2O; SbO+O+M=SbO2+M. The inhibition cycles of antimony are shown to be more effective than those of bromine, and intermediate between the highly effective agents CF3Br and trimethylphosphate. Preliminary examination of a Sb/Br gas-phase system did not show synergism in the gas-phase catalytic cycles (i.e., they acted essentially independently).

  13. Antimony and arsenic biogeochemistry in the East China Sea

    NASA Astrophysics Data System (ADS)

    Ren, Jing-Ling; Zhang, Xu-Zhou; Sun, You-Xu; Liu, Su-Mei; Huang, Daji; Zhang, Jing

    2016-02-01

    The biogeochemical cycles of the metalloid elements arsenic and antimony in the East China Sea (ECS), one of the most important marginal seas for western Pacific, were examined in May 2011. Dissolved inorganic arsenic (As(V) and As(III)) and antimony (Sb(V) and Sb(III)) species were determined by selective hydride generation-atomic fluorescence spectrometry (HG-AFS). Results show that total dissolved inorganic arsenic (TDIAs; [TDIAs]=[As(V)]+[As(III)]) were moderately depleted in the surface water and enriched in the deep water. Arsenite (As(III)) showed different vertical profiles with that of TDIAs, with significant surface enrichment in the middle shelf region where the concentrations of phosphate were extremely low. Speciation of dissolved arsenic was subtly controlled by the stoichiometric molar ratio of arsenate (As(V)) to phosphate. The average As(V)/P ratio for the ECS in spring 2011 was 10.8×10-3, which is higher than previous results and indicates the arsenate stress. The concentrations of total dissolved inorganic antimony (TDISb; [TDISb]=[Sb(V)]+[Sb(III)]) were high near the Changjiang Estuary and the coastal area of Hangzhou Bay and decreased moderately off the coast. TDISb displayed moderate conservative behavior in the ECS that confirms by the correlations with salinity and dissolved aluminum. Different with that of As(III), antimonite (Sb(III)) concentrations were extremely lower in the ECS, with relative higher concentration appeared at the bottom layer which indicates the contribution from sediment-water interface. A preliminary box model was established to estimate the water-mass balance and antimony budgets for the ECS. Compared with other areas in the world, the concentrations of dissolved inorganic arsenic and antimony in the ECS remain at natural levels.

  14. New organoruthenium complexes with bioactive thiosemicarbazones as co-ligands: potential anti-trypanosomal agents†

    PubMed Central

    Demoro, Bruno; Sarniguet, Cynthia; Sánchez-Delgado, Roberto; Rossi, Miriam; Liebowitz, Daniel; Caruso, Francesco; Olea-Azar, Claudio; Moreno, Virtudes; Medeiros, Andrea; Comini, Marcelo A.; Otero, Lucía; Gambino, Dinorah

    2012-01-01

    In the search for new therapeutic tools against neglected diseases produced by trypanosomatid parasites, and particularly against African Trypanosomiasis, whose etiological agent is Trypanosoma brucei, organoruthenium compounds with bioactive nitrofuran containing thiosemicarbazones (L) as co-ligands were obtained. Four ruthenium(ii) complexes with the formula [Ru2(p-cymene)2(L)2]X2, where X = Cl or PF6, were synthesized and the crystal structures of two of them were solved by X-ray diffraction methods. Two of the complexes show significant in vitro growth inhibition activity against Trypanosoma brucei brucei and are highly selective towards trypanosomal cells with respect to mammalian cells (J774 murine macrophages). These promising results make the title organoruthenium compounds good lead candidates for further developments towards potential antitrypanosomal organometallic drugs. PMID:22138896

  15. Novel aldehyde and thiosemicarbazone derivatives: Synthesis, spectroscopic characterization, structural studies and molecular docking studies

    NASA Astrophysics Data System (ADS)

    Karakurt, Tuncay; Tahtaci, Hakan; Subasi, Nuriye Tuna; Er, Mustafa; Ağar, Erbil

    2016-12-01

    In this study our purpose is that, synthesis and characterization of compounds containing the aldehyde and thiosemicarbazone groups and comparison of the theoretical results with the experimental results. The structures of all synthesized compounds were elucidated by IR, 1H NMR, 13C NMR, elemental analyses techniques. The structure of compound (4) (C9H8N4O2S) was also elucidated by X-ray diffraction analysis. In addition, the theoretical IR spectrum, 1H NMR and 13C NMR chemical shift values, frontier molecular orbital values (FMO) of these molecules were analyzed by using Becke-3- Lee-Yang-Parr (B3LYP) method with LanL2DZ basis set. Finally, molecular docking studies were performed on synthesized compounds using the 4DKI beta-lactam protein structure to determine the potential binding mode of inhibitors.

  16. Novel ruthenium(II) cyclopentadienyl thiosemicarbazone compounds with antiproliferative activity on pathogenic trypanosomatid parasites.

    PubMed

    Fernández, Mariana; Arce, Esteban Rodríguez; Sarniguet, Cynthia; Morais, Tânia S; Tomaz, Ana Isabel; Azar, Claudio Olea; Figueroa, Roberto; Diego Maya, J; Medeiros, Andrea; Comini, Marcelo; Helena Garcia, M; Otero, Lucía; Gambino, Dinorah

    2015-12-01

    Searching for new prospective antitrypanosomal agents, three novel Ru(II)-cyclopentadienyl compounds, [Ru(η(5)-C5H5)(PPh3)L], with HL=bioactive 5-nitrofuryl containing thiosemicarbazones were synthesized and characterized in the solid state and in solution. The compounds were evaluated in vitro on the blood circulating trypomastigote form of Trypanosoma cruzi (Dm28c strain), the infective form of Trypanosoma brucei brucei (strain 427) and on J774 murine macrophages and human-derived EA.hy926 endothelial cells. The compounds were active against both parasites with IC50 values in the micromolar or submicromolar range. Interestingly, they are much more active on T. cruzi than previously developed Ru(II) classical and organometallic compounds with the same bioactive ligands. The new compounds showed moderate to very good selectivity towards the parasites in respect to mammalian cells. The global results point at [RuCp(PPh3)L2] (L2=N-methyl derivative of 5-nitrofuryl containing thiosemicarbazone and Cp=cyclopentadienyl) as the most promising compound for further developments (IC50T. cruzi=0.41μM; IC50T. brucei brucei=3.5μM). Moreover, this compound shows excellent selectivity towards T. cruzi (SI>49) and good selectivity towards T. brucei brucei (SI>6). In order to get insight into the mechanism of antiparasitic action, the intracellular free radical production capacity of the new compounds was assessed by ESR. DMPO (5,5-dimethyl-1-pirroline-N-oxide) spin adducts related to the bioreduction of the complexes and to redox cycling processes were characterized. In addition, DNA competitive binding studies with ethidium bromide by fluorescence measurements showed that the compounds interact with this biomolecule.

  17. Rhenium(I) tricarbonyl compounds of bioactive thiosemicarbazones: Synthesis, characterization and activity against Trypanosoma cruzi.

    PubMed

    Rodríguez Arce, Esteban; Machado, Ignacio; Rodríguez, Belén; Lapier, Michel; Zúñiga, María Carolina; Maya, Juan Diego; Olea Azar, Claudio; Otero, Lucía; Gambino, Dinorah

    2017-05-01

    American Trypanosomiasis is a chronic infection discovered and described in 1909 by the Brazilian scientist Carlos Chagas. It is caused by the protozoan parasite Trypanosoma cruzi. Although it affects about 10million people in Latin America, the current chemotherapy is still inadequate. The discovery of new drugs is urgently needed. Our group is focused on the development of prospective metal-based drugs mainly based on bioactive ligands and pharmacologically interesting metal ions. In this work three new rhenium(I) tricarbonyl compounds fac-[Re(I)(CO)3Br(HL)] where HL=5-nitrofuryl containing thiosemicarbazones were synthesized and fully characterized in solution and in the solid state. The in vitro evaluation of the compounds on T. cruzi trypomastigotes (Dm28c strain) showed that the Re(I) compounds are 8 to 15 times more active than the reference drug Nifurtimox and show a 4 to 17 fold increase in activity in respect to the free (HL) ligands. Obtained compounds also show good selectivity indexes (IC50 endothelial cells Ea.hy926/IC50 T. cruzi (Dm28c tripomastigotes)). (1)H NMR and MS studies, performed with time, showed that the fac-[Re(CO)3Br(HL)] species convert into the dimers [Re2(CO)6(L)2] in solution. Crystal structure of [Re(I)2(CO)6(L2)2], the product of complexes' dimerization, was solved. Related to the mechanism of action, the studied compounds do not generate radical oxygen species in the parasite (as 5-nitrofuryl derived thiosemicarbazones do) probably due to the unfavorable nitro reduction potential of the generated dimeric species. On the contrary, the compounds produce a decrease of the oxygen consumption rate of the parasites, maybe inhibiting their mitochondrial respiration.

  18. Antimony and arsenic biogeochemistry in the western Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    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

  19. BioGeochemistry of antimony, Sources, Transfers, Impacts and Assessment

    NASA Astrophysics Data System (ADS)

    Le Roux, Gael; Pinelli, Eric; Hedde, Mickael; Guiresse, Maritxu; De Vleeschouwer, François; Silvestre, Jérôme; Enrico, Maxime; Gandois, Laure; Monna, Fabrice; Gers, Charles; Probst, Anne

    2013-04-01

    BioGeoSTIB is a project funded by ADEME (French Environmental Protection Agency). Its aim is to provide a better understanding of biogeochemical cycle disturbances of antimony by man. Specifically, it is focused on the atmosphere-soil-organism interfaces. Based on a multi-scale approach, the impact of antimony on organisms and organism communities and the factors of Sb dispersion in the environment aim to better characterized. This report gives the main results of 2 and 1 -2 years of research. Using peat bogs as environmental archives, we show that Sb contamination in soils date back to the beginning of the metallurgy. Atmospheric deposition of Sb largely increased by 100 times during the Industrial Revolution compared to natural levels (~0,001-0,01 mg m-2 an-1) estimated in the deepest peat layers. This disturbance in the antimony geochemical cycle modified its concentrations in soils. One main source of present Sb contamination is automotive traffic due to Sb in braking lines. This emerging contamination was characterized close to a roundabout. This additional source of Sb does not seem to impact soil fauna but Sb concentrations in soil solutions exceed 1 μg L-1. Genotoxicity tests have been performed on the model plant Vicia faba and show that antimony is genotoxic at its lowest concentrations and that there is a synergistic effect lead, a trace metal frequently found in association with antimony in the environment. It is a main issue to determine Sb critical loads in the environment but main identified lacks are thermodynamic data, which are not available yet, to model the behavior of Sb in soil solutions and the fact the antimony is always associated with other anthropogenic trace metals like lead. Critical thresholds of Sb have been determined for the first time based on genotoxicity experiment. Simulations show that these thresholds can be exceeded in the future, whereas present limits for invertebrates (US-EPA) are and will not be reached. However

  20. Synthesis, characterization, and preliminary in vitro studies of vanadium(IV) complexes with a Schiff base and thiosemicarbazones as mixed-ligands.

    PubMed

    Lewis, Nerissa A; Liu, Fange; Seymour, Luke; Magnusen, Anthony; Erves, Travis R; Arca, Jessa Faye; Beckford, Floyd A; Venkatraman, Ramaiyer; González-Sarrías, Antonio; Fronczek, Frank R; Vanderveer, Don G; Seeram, Navindra P; Liu, Aimin; Jarrett, William L; Holder, Alvin A

    2012-02-01

    [VO(Sal-L-tryp)(H2O)] 1 (where sal-L-tryp = N-salicylidene-L-tryptophanate) was used as a precursor to produce the novel complexes, [VO(Sal-L-tryp)(MeATSC)].1.5C2H5OH 2 (where MeATSC = 9-Anthraldehyde-N(4)-methylthiosemicarbazone), [VO(Sal-L-tryp)(N-Ethhymethohcarbthio)].H2O 3 (where N-Ethhymethohcarbthio = (E)-N-ethyl-2-(4-hydroxy-3-methoxybenzylidene)hydrazinecarbothioamide), and [VO(Sal-L-tryp)(acetylethTSC)].C2H5OH 4 (where acetylethTSC = (E)-N-ethyl-2-(1-(thiazol-2-yl)ethylidene)hydrazinecarbothioamide), by reaction with the respective thiosemicarbazone. The chemical and structural properties of these ligands and complexes were characterised by elemental analysis, ESI MS, FT-IR, UV-visible, ESR, (1)H and (13)C NMR spectroscopy, and X-ray crystallography. DMSO and DMSO-d6 solutions of compounds 1-4 were oxidised in air to produce vanadium(V) species which were verified by ESI MS and (51)V NMR spectroscopy. Anti-cancer properties of compounds 2-4 were examined with three colon cancer cell lines, HTC-116, Caco-2, and HT-29, and also with non-cancerous colonic myofibroblasts, CCD18-Co. Compounds 2-3 exhibited less inhibitory effects in the CCD-18Co cells, indicating a possible cytotoxic selectivity towards colon cancer cells. In general, those compounds which exhibited anti-proliferative activity on cancer cells, but did not affect non-cancerous cells, may have a potential in chemotherapy.

  1. G2/M Cell Cycle Arrest and Tumor Selective Apoptosis of Acute Leukemia Cells by a Promising Benzophenone Thiosemicarbazone Compound

    PubMed Central

    Cabrera, Maia; Gomez, Natalia; Remes Lenicov, Federico; Echeverría, Emiliana; Shayo, Carina; Moglioni, Albertina; Fernández, Natalia; Davio, Carlos

    2015-01-01

    Anti-mitotic therapies have been considered a hallmark in strategies against abnormally proliferating cells. Focusing on the extensively studied family of thiosemicarbazone (TSC) compounds, we have previously identified 4,4’-dimethoxybenzophenone thiosemicarbazone (T44Bf) as a promising pharmacological compound in a panel of human leukemia cell lines (HL60, U937, KG1a and Jurkat). Present findings indicate that T44Bf-mediated antiproliferative effects are associated with a reversible chronic mitotic arrest caused by defects in chromosome alignment, followed by induced programmed cell death. Furthermore, T44Bf selectively induces apoptosis in leukemia cell lines when compared to normal peripheral blood mononuclear cells. The underlying mechanism of action involves the activation of the mitochondria signaling pathway, with loss of mitochondrial membrane potential and sustained phosphorylation of anti-apoptotic protein Bcl-xL as well as increased Bcl-2 (enhanced phosphorylated fraction) and pro-apoptotic protein Bad levels. In addition, ERK signaling pathway activation was found to be a requisite for T44Bf apoptotic activity. Our findings further describe a novel activity for a benzophenone thiosemicarbazone and propose T44Bf as a promising anti-mitotic prototype to develop chemotherapeutic agents to treat acute leukemia malignancies. PMID:26360247

  2. Copper(II) complexes with 2-pyridineformamide-derived thiosemicarbazones: Spectral studies and toxicity against Artemia salina

    NASA Astrophysics Data System (ADS)

    Ferraz, Karina O.; Wardell, Solange M. S. V.; Wardell, James L.; Louro, Sonia R. W.; Beraldo, Heloisa

    2009-07-01

    The copper(II) complexes [Cu(H2Am4DH)Cl 2] ( 1), [Cu(H2Am4Me)Cl 2] ( 2), [Cu(H2Am4Et)Cl 2] ( 3) and [Cu(2Am4Ph)Cl] ( 4) with 2-pyridineformamide thiosemicarbazone (H2Am4DH) and its N(4)-methyl (H2Am4Me), N(4)-ethyl (H2Am4Et) and N(4)-phenyl (H2Am4Ph) derivatives were studied by means of infrared and EPR spectral techniques. The crystal structure of 4 was determined. The studied compounds proved to be toxic to Artemia salina, suggesting that they could present cytotoxic activity against solid tumors. Among the free thiosemicarbazones H2Am4Ph presented higher toxicity than all other compounds, which showed comparable effects. In the case of complexes 2 and 3 toxicity is probably attributable to the complex as an entity or to a synergistic effect involving the thiosemicarbazone and copper. H2Am4Ph and complexes 2 and 3 revealed to be the most promising compounds as potential antineoplasic agents.

  3. Molecular and supramolecular properties of nitroaromatic thiosemicarbazones: Synthesis, spectroscopy, X-ray structure elucidation and DFT calculations

    NASA Astrophysics Data System (ADS)

    Dias, L. C.; de Lima, G. M.; Pinheiro, C. B.; Nascimento, M. A. C.; Bitzer, R. S.

    2017-03-01

    The reactions of 6-nitropiperonal with H2Nsbnd NHsbnd C(S)sbnd NHR, R = Me, Et, Ph or H, afforded four nitroaromatic thiosemicarbazones 1-4, respectively. 1-4 were characterized by elemental analysis (CHN), FTIR, and 1H and 13C{1H} NMR spectroscopy. In addition, the crystal structures of 2 and 3 were determined by single-crystal X-ray diffraction. Our X-ray structural results have shown that the nitropiperonal and thiosemicarbazone moieties exhibit an almost coplanar arrangement for both 2 and 3. Moreover, they establish 2-D networks along the [111] base vector by means of classical and nonclassical hydrogen bonds. Electronic and spectroscopic properties of 1-4 were investigated at the DFT B3LYP/6-311G** level of calculation. The Cdbnd S group of 1-4 constitutes a nucleophilic region, whereas the NO2 group defines an electrophilic centre, as expected. Furthermore, a DFT vibrational analysis of 4 allowed a reliable assignment of the thiosemicarbazone-based vibrations. Also, a good agreement between theoretical and experimental 13C chemical shift values was obtained for 1-4.

  4. Identification of antimony- and arsenic-oxidizing bacteria associated with antimony mine tailing.

    PubMed

    Hamamura, Natsuko; Fukushima, Koh; Itai, Takaaki

    2013-01-01

    Antimony (Sb) is a naturally occurring toxic element commonly associated with arsenic (As) in the environment and both elements have similar chemistry and toxicity. Increasing numbers of studies have focused on microbial As transformations, while microbial Sb interactions are still not well understood. To gain insight into microbial roles in the geochemical cycling of Sb and As, soils from Sb mine tailing were examined for the presence of Sb- and As-oxidizing bacteria. After aerobic enrichment culturing with As(III) (10 mM) or Sb(III) (100 μM), pure cultures of Pseudomonas- and Stenotrophomonas-related isolates with Sb(III) oxidation activities and a Sinorhizobium-related isolate capable of As(III) oxidation were obtained. The As(III)-oxidizing Sinorhizobium isolate possessed the aerobic arsenite oxidase gene (aioA), the expression of which was induced in the presence of As(III) or Sb(III). However, no Sb(III) oxidation activity was detected from the Sinorhizobium-related isolate, suggesting the involvement of different mechanisms for Sb and As oxidation. These results demonstrate that indigenous microorganisms associated with Sb mine soils are capable of Sb and As oxidation, and potentially contribute to the speciation and mobility of Sb and As in situ.

  5. Synthesis, structural characterization, and pro-apoptotic activity of 1-indanone thiosemicarbazone platinum(II) and palladium(II) complexes: potential as antileukemic agents.

    PubMed

    Gómez, Natalia; Santos, Diego; Vázquez, Ramiro; Suescun, Leopoldo; Mombrú, Alvaro; Vermeulen, Monica; Finkielsztein, Liliana; Shayo, Carina; Moglioni, Albertina; Gambino, Dinorah; Davio, Carlos

    2011-08-01

    In the search for alternative chemotherapeutic strategies against leukemia, various 1-indanone thiosemicarbazones, as well as eight novel platinum(II) and palladium(II) complexes, with the formula [MCl₂(HL)] and [M(HL)(L)]Cl, derived from two 1-indanone thiosemicarbazones were synthesized and tested for antiproliferative activity against the human leukemia U937 cell line. The crystal structure of [Pt(HL1)(L1)]Cl·2MeOH, where L1=1-indanone thiosemicarbazone, was solved by X-ray diffraction. Free thiosemicarbazone ligands showed no antiproliferative effect, but the corresponding platinum(II) and palladium(II) complexes inhibited cell proliferation and induced apoptosis. Platinum(II) complexes also displayed selective apoptotic activity in U937 cells but not in peripheral blood monocytes or the human hepatocellular carcinoma HepG2 cell line used to screen for potential hepatotoxicity. Present findings show that, in U937 cells, 1-indanone thiosemicarbazones coordinated to palladium(II) were more cytotoxic than those complexed with platinum(II), although the latter were found to be more selective for leukemic cells suggesting that they are promising compounds with potential therapeutic application against hematological malignancies.

  6. Antimony-assisted carbonization of Si(111) with solid source molecular beam epitaxy

    SciTech Connect

    Hackley, Justin; Richardson, Christopher J. K.; Sarney, Wendy L.

    2013-11-15

    The carbonization of an antimony-terminated Si (111) surface in a solid source molecular beam epitaxy system is presented. Reflection high-energy electron diffraction, atomic force microscopy, x-ray photoelectron spectroscopy, and cross-sectional transmission electron microscopy are used to characterize samples grown with and without antimony termination. It is shown that the antimony-terminated surface promotes the formation of thin, smooth and continuous SiC films at a relatively low temperature of 800 °C.

  7. Surface segregation of antimony in Fe-Si steel for grain oriented sheets

    NASA Astrophysics Data System (ADS)

    Jenko, M.; Vodopivec, F.; Praček, B.

    1993-06-01

    Surface segregation of antimony in a polycrystalline Fe-Si alloy with 0.049 wt% Sb was investigated by Auger electron spectroscopy in the temperature range from 450 to 800°C, and the segregation kinetics of antimony were described. From the surface segregation kinetics and its temperature dependence the bulk diffusion coefficient of antimony and the activation energy were determined in the temperature range from 500 to 600°C.

  8. Selective synthesis of ternary copper-antimony sulfide nanocrystals.

    PubMed

    Xu, Dongying; Shen, Shuling; Zhang, Yejun; Gu, Hongwei; Wang, Qiangbin

    2013-11-18

    Ternary copper-antimony sulfide nanocrystals (CAS NCs) have attracted increasing attention in photovoltaics and photoelectric nanodevices due to their tunable band gaps in the near-IR regime. Although much progress in the synthesis of CAS NCs has been achieved, the selective synthesis of CAS NCs with controllable morphologies and compositions is preliminary: in particular, a facile method is still in demand. In this work, we have successfully selectively synthesized high-quality CAS NCs with diverse morphologies, compositions, and band gaps, including rectangular CuSbS2 nanosheets (NSs), trigonal-pyramidal Cu12Sb4S13 NCs, and rhombic Cu3SbS3 NSs, by cothermodecomposition of copper diethyldithiocarbamate trihydrate (Cu(Ddtc)2) and antimony diethyldithiocarbamate trihydrate (Sb(Ddtc)3). The direct and indirect band gaps of the obtained CAS NCs were systematically studied by performing Kubelka-Munk transformations of their solid-state diffuse reflectance spectra.

  9. [Miltefosine versus meglumine antimoniate in the treatment of mucosal leishmaniasis].

    PubMed

    Garcia Bustos, Maria F; Barrio, Alejandra; Parodi, Cecilia; Beckar, Josefina; Moreno, Sonia; Basombrio, Miguel A

    2014-01-01

    The conventional treatment for tegumentary leishmaniasis is meglumine antimoniate, which needs parenteral administration, has increased therapeutic failure, and produces serious adverse effects, justifying the search for therapeutic alternatives. We report here the preliminary results of a phase II clinical trial in patients with mucosal leishmaniasis, in which the efficacy of oral miltefosine versus the antimonial compound was assessed. The evaluation of response to the treatment was performed by monitoring with nasopharyngeal video-fibroscopy, using a score of mucosal injury severity for patients at each follow-up point. We found no significant differences so far between the number of patients cured with miltefosine or conventional chemotherapy. The favorable results of this study suggest that miltefosine could be an effective and safe oral therapeutic alternative in the region.

  10. [Premature birth after the use of pentavalent antimonial: case report].

    PubMed

    Silveira, Bruna Pinheiro; Araújo Sobrinho, José; Leite, Lacínia Freire; Sales, Maria das Neves Andrade; Gouveia, Maria do Socorro Araújo; Mathias, Renato Leal; Guedes Filho, Ricardo Amorim; Barbosa, Sônia Maria

    2003-01-01

    A case is reported of a 19-year-old woman, at week 24 of gestation, with visceral leishmaniosis. She was treated with meglumine antimoniate at a dose of 850 mg/day for 20 days. There occurred premature birth on day five of treatment and the neonate died one day after birth. Considering the importance of protozoiasis in our population and the rarity of the association with pregnancy, we resolved to publish the case.

  11. Comparison of Meglumine Antimoniate and Pentamidine for Peruvian Cutaneous Leishmaniasis

    DTIC Science & Technology

    2005-01-01

    2002. Patients. The patients lived in and around the city of Cusco, Peru and presented with a clinical diagnosis of cutaneous leishmaniasis ...for investigation of chemotherapeutic agents in leishmaniasis . J Infect Dis 142: 83–86. 8. Davey RT, Masur H, 1990. Recent advances in the diagnosis ...COMPARISON OF MEGLUMINE ANTIMONIATE AND PENTAMIDINE FOR PERUVIAN CUTANEOUS LEISHMANIASIS ELLEN M. ANDERSEN, MARIA CRUZ-SALDARRIAGA, ALEJANDRO LLANOS

  12. Correlation of CsK2Sb photocathode lifetime with antimony thickness

    SciTech Connect

    Mamun, M. A.; Hernandez-Garcia, C.; Poelker, M.; Elmustafa, A. A.

    2015-06-01

    CsK2Sb photocathodes with quantum efficiency on the order of 10% at 532 nm, and lifetime greater than 90 days at low voltage, were successfully manufactured via co-deposition of alkali species emanating from an effusion source. Photocathodes were characterized as a function of antimony layer thickness and alkali consumption, inside a vacuum chamber that was initially baked, but frequently vented without re-baking. Photocathode lifetime measured at low voltage is correlated with the antimony layer thickness. Photocathodes manufactured with comparatively thick antimony layers exhibited the best lifetime. We speculate that the antimony layer serves as a reservoir, or sponge, for the alkali.

  13. Correlation of CsK{sub 2}Sb photocathode lifetime with antimony thickness

    SciTech Connect

    Mamun, M. A. Elmustafa, A. A.; Hernandez-Garcia, C.; Poelker, M.

    2015-06-01

    CsK{sub 2}Sb photocathodes with quantum efficiency on the order of 10% at 532 nm, and lifetime greater than 90 days at low voltage, were successfully manufactured via co-deposition of alkali species emanating from an effusion source. Photocathodes were characterized as a function of antimony layer thickness and alkali consumption, inside a vacuum chamber that was initially baked, but frequently vented without re-baking. Photocathode lifetime measured at low voltage is correlated with the antimony layer thickness. Photocathodes manufactured with comparatively thick antimony layers exhibited the best lifetime. We speculate that the antimony layer serves as a reservoir, or sponge, for the alkali.

  14. Kinetics and mechanism of photopromoted oxidative dissolution of antimony trioxide.

    PubMed

    Hu, Xingyun; Kong, Linghao; He, Mengchang

    2014-12-16

    Light (sunlight, ultraviolet, simulated sunlight) irradiation was used to initiate the dissolution of antimony trioxide (Sb2O3). Dissolution rate of Sb2O3 was accelerated and dissolved trivalent antimony (Sb(III)) was oxidized in the irradiation of light. The photopromoted oxidative dissolution mechanism of Sb2O3 was studied through experiments investigating the effects of pH, free radicals scavengers, dissolved oxygen removal and Sb2O3 dosage on the release rate of antimony from Sb2O3 under simulated sunlight irradiation. The key oxidative components were hydroxyl free radicals, photogenerated holes and superoxide free radicals; their contribution ratios were roughly estimated. In addition, a conceptual model of the photocatalytic oxidation dissolution of Sb2O3 was proposed. The overall pH-dependent dissolution rate of Sb2O3 and the oxidation of Sb(III) under light irradiation were expressed by r = 0.08 ·[OH(-)](0.63) and rox = 0.10 ·[OH(-)](0.79). The present study on the mechanism of the photo-oxidation dissolution of Sb2O3 could help clarify the geochemical cycle and fate of Sb in the environment.

  15. Half-sandwich ruthenium-arene complexes with thiosemicarbazones: Synthesis and biological evaluation of [(η6-p-cymene)Ru(piperonal thiosemicarbazones)Cl]Cl complexes

    PubMed Central

    Dourth, Deidra; Shaloski, Michael; Didion, Jacob; Thessing, Jeffrey; Woods, Jason; Crowell, Vernon; Gerasimchuk, Nikolay; Gonzalez-Sarrías, Antonio; Seeram, Navindra P.

    2011-01-01

    The synthesis and characterization of a number of organometallic ruthenium(II) complexes containing a series of bidentate thiosemicarbazone ligands derived from piperonal is reported. The structure of compounds have been confirmed by spectroscopic analysis (IR and NMR) as well as X-ray crystallographic analysis of [(η6-p-cymene)Ru(pPhTSC)Cl]Cl (4) (pPhTSC is piperonal-N(4)-phenylthiosemicarbazone). The interaction of the complexes ([(η6-p-cymene)Ru(pEtTSC)Cl]Cl) (3) (pEtTSC is piperonal-N(4)-ethylthiosemicarbazone) and 4 with calf thymus DNA, human serum albumin (HSA) and pBR322 plasmid DNA were studied by spectroscopic, gel electrophoresis and hydrodynamic methods. The apparent binding constant for the interaction with DNA was determined to be 3.97 × 103 M−1 and 4.07 × 103 M−1 at 293 K for 3 and 4 respectively. The complexes bind strongly to HSA with binding constants of 2.94 × 104 M−1 and 12.2 × 104 M−1 at 296 K for 3 and 4 respectively. The in vitro anticancer activity of 3 and 4 has been evaluated against two human colon cancer cell line (HCT-116 and Caco-2) with IC50 values in the range 26 – 150 µM. Both 3 and 4 show good activity as a catalytic inhibitor of human topoisomerase II at concentrations as low as 20 µM. The proficiency of 3 and 4 to act as antibacterial agents was also evaluated against six pathogenic bacterial strains with the best activity seen against Gram-positive strains. PMID:21666776

  16. Synthesis, Characterization, Electrochemical Studies, and In Vitro Antibacterial Activity of Novel Thiosemicarbazone and Its Cu(II), Ni(II), and Co(II) Complexes

    PubMed Central

    Khan, Salman A.; Asiri, Abdullah M.; Al-Amry, Khalid; Malik, Maqsood Ahmad

    2014-01-01

    Metal complexes were prepared by the reaction of thiosemicarbazone with CuCl2, NiCl2, CoCl2, Cu(OAc)2, Ni(OAc)2, and Co(OAc)2. The thiosemicarbazone coordinates to metal through the thionic sulfur and the azomethine nitrogen. The thiosemicarbazone was obtained by the thiosemicarbazide with 3-acetyl-2,5-dimethylthiophene. The identities of these compounds were elucidated by IR, 1H, 13C-NMR, and GC-MS spectroscopic methods and elemental analyses. The antibacterial activity of these compounds was first tested in vitro by the disc diffusion assay against two Gram-positive and two Gram-negative bacteria, and then the minimum inhibitory concentration (MIC) was determined by using chloramphenicol as reference drug. The results showed that compound 1.1 is better inhibitor of both types of tested bacteria as compared to chloramphenicol. PMID:24523641

  17. Structural, optical and charge generation properties of chalcostibite and tetrahedrite copper antimony sulfide thin films prepared from metal xanthates† †Electronic supplementary information (ESI) available: Chemical structures of the used metal xanthates, additional XRD, SEM-EDX and UV-vis data. See DOI: 10.1039/c5ta05777a Click here for additional data file.

    PubMed Central

    MacLachlan, Andrew J.; Brown, Michael D.

    2015-01-01

    Herein, we report on a solution based approach for the preparation of thin films of copper antimony sulfide, an emerging absorber material for third generation solar cells. In this work, copper and antimony xanthates are used as precursor materials for the formation of two different copper antimony sulfide phases: chalcostibite (CuSbS2) and tetrahedrite (Cu12Sb4S13). Both phases were thoroughly investigated regarding their structural and optical properties. Moreover, thin films of chalcostibite and tetrahedrite were prepared on mesoporous TiO2 layers and photoinduced charge transfer in these metal sulfide/TiO2 heterojunctions was studied via transient absorption spectroscopy. Photoinduced charge transfer was detected in both the chalcostibite as well as the tetrahedrite sample, which is an essential property in view of applying these materials as light-harvesting agents in semiconductor sensitized solar cells. PMID:27019713

  18. Antimony leaching from polyethylene terephthalate (PET) plastic used for bottled drinking water.

    PubMed

    Westerhoff, Paul; Prapaipong, Panjai; Shock, Everett; Hillaireau, Alice

    2008-02-01

    Antimony is a regulated contaminant that poses both acute and chronic health effects in drinking water. Previous reports suggest that polyethylene terephthalate (PET) plastics used for water bottles in Europe and Canada leach antimony, but no studies on bottled water in the United States have previously been conducted. Nine commercially available bottled waters in the southwestern US (Arizona) were purchased and tested for antimony concentrations as well as for potential antimony release by the plastics that compose the bottles. The southwestern US was chosen for the study because of its high consumption of bottled water and elevated temperatures, which could increase antimony leaching from PET plastics. Antimony concentrations in the bottled waters ranged from 0.095 to 0.521 ppb, well below the US Environmental Protection Agency (USEPA) maximum contaminant level (MCL) of 6 ppb. The average concentration was 0.195+/-0.116 ppb at the beginning of the study and 0.226+/-0.160 ppb 3 months later, with no statistical differences; samples were stored at 22 degrees C. However, storage at higher temperatures had a significant effect on the time-dependent release of antimony. The rate of antimony (Sb) release could be fit by a power function model (Sb(t)=Sb 0 x[Time, h]k; k=8.7 x 10(-6)x[Temperature ( degrees C)](2.55); Sb 0 is the initial antimony concentration). For exposure temperatures of 60, 65, 70, 75, 80, and 85 degrees C, the exposure durations necessary to exceed the 6 ppb MCL are 176, 38, 12, 4.7, 2.3, and 1.3 days, respectively. Summertime temperatures inside of cars, garages, and enclosed storage areas can exceed 65 degrees C in Arizona, and thus could promote antimony leaching from PET bottled waters. Microwave digestion revealed that the PET plastic used by one brand contained 213+/-35 mgSb/kg plastic; leaching of all the antimony from this plastic into 0.5L of water in a bottle could result in an antimony concentration of 376 ppb. Clearly, only a small

  19. Heavy weight vehicle traffic and its relationship with antimony content in human blood.

    PubMed

    Quiroz, Waldo; De Gregori, Ida; Basilio, Paola; Bravo, Manuel; Pinto, Marcela; Lobos, Maria Gabriela

    2009-05-01

    Brake pads systems are nowadays considered as one of the most important sources of antimony in airborne particulate matter. One way that antimony can enter the body is through the lungs and specially by the interaction of antimony with -SH groups present in erythrocyte membrane cells. In spite of that, there are no studies about antimony enrichment in blood of workers exposed to high vehicle traffic. Port workers are generally exposed to heavy weight vehicle traffic. In Chile the biggest marine port is found in Valparaíso City. In this study antimony in whole blood and its fractions (erythrocytes-plasma and erythrocytes membranes-cytoplasm) of 45 volunteers were determined. The volunteers were port workers from Valparaíso city, and two control groups, one from Valparaíso and another from Quebrada Alvarado, the latter being a rural area located about 100 Km away from Valparaíso. The results demonstrate that port workers are highly impacted by antimony emissions from heavy weight vehicle traffic showing an average concentration of 27 +/- 9 ng Sb kg(-1), 5-10 times higher than the concentration of antimony in the blood of control groups. These are the highest antimony levels in blood ever reported in the literature. The highest antimony percentages (>60%) were always found in the erythrocyte fractions. However, the exposure degree to vehicle traffic is significant over antimony distribution in plasma, erythrocytes and cytoplasm. This results shows that the antimony mass in the erythrocyte membranes, was approximately constant at 1.0 +/- 0.1 ng Sb g(-1) of whole blood in all blood samples analyzed.

  20. Ornithine decarboxylase or gamma-glutamylcysteine synthetase overexpression protects Leishmania (Vianna) guyanensis against antimony.

    PubMed

    Fonseca, Maisa S; Comini, Marcelo A; Resende, Bethânia V; Santi, Ana Maria M; Zoboli, Antônio P; Moreira, Douglas S; Murta, Silvane M F

    2017-04-01

    Trypanosomatids present a unique mechanism for detoxification of peroxides that is dependent on trypanothione (bisglutathionylspermidine). Ornithine decarboxylase (ODC) and γ-glutamylcysteine synthetase (GSH1) produce molecules that are direct precursors of trypanothione. In this study, Leishmania guyanensis odc and gsh1 overexpressor cell lines were generated to investigate the contribution of these genes to the trivalent antimony (Sb(III))-resistance phenotype. The ODC- or GSH1-overexpressors parasites presented an increase of two and four-fold in Sb(III)-resistance index, respectively, when compared with the wild-type line. Pharmacological inhibition of ODC and GSH1 with the specific inhibitors α-difluoromethylornithine (DFMO) and buthionine sulfoximine (BSO), respectively, increased the antileishmanial effect of Sb(III) in all cell lines. However, the ODC- and GSH1-overexpressor were still more resistant to Sb(III) than the parental cell line. Together, our data shows that modulation of ODC and GSH1 levels and activity is sufficient to affect L. guyanensis susceptibility to Sb(III), and confirms a role of these genes in the Sb(III)-resistance phenotype.

  1. Facile synthesis of antimony-doped tin oxide nanoparticles by a polymer-pyrolysis method

    SciTech Connect

    Li, Yuan-Qing; Wang, Jian-Lei; Fu, Shao-Yun; Mei, Shi-Gang; Zhang, Jian-Min; Yong, Kang

    2010-06-15

    In this article, antimony-doped tin oxide (ATO) nanoparticles was synthesized by a facile polymer-pyrolysis method. The pyrolysis behaviors of the polymer precursors prepared via in situ polymerization of metal salts and acrylic acid were analyzed by simultaneous thermogravimetric and differential scanning calorimetry (TG-DSC). The structural and morphological characteristics of the products were studied by powder X-ray diffraction (XRD) and transmission electron microscope (TEM). The results reveal that the ATO nanoparticles calcined at 600 {sup o}C show good crystallinity with the cassiterite structure and cubic-spherical like morphology. The average particle size of ATO decreases from 200 to 15 nm as the Sb doping content increases from 5 mol% to 15 mol%. Electrical resistivity measurement shows that the resistivity for the 10-13 mol% Sb-doped SnO{sub 2} nanoparticles is reduced by more than three orders compared with the pure SnO{sub 2} nanoparticles. In addition, due to its versatility this polymer-pyrolysis method can be extended to facile synthesis of other doped n-type semiconductor, such as In, Ga, Al doped ZnO, Sn doped In{sub 2}O{sub 3}.

  2. Supramolecular interactions in biologically relevant compounds. 2-Pyrazineformamide thiosemicarbazones and some products of their cyclization

    NASA Astrophysics Data System (ADS)

    Castiñeiras, Alfonso; García-Santos, Isabel; Nogueiras, Silvia; Rodríguez-González, Iria; Rodríguez-Riobó, Raúl

    2014-09-01

    Reaction of 2-cyanopyrazine with thiosemicarbazide or N-methylthiosemicarbazide afforded the (Z)-2-(amino(pyrazin-2-yl)methylene)hydrazinecarbothioamide (HPzAm4DH) and (Z)-2-(amino(pyrazin-2-yl)methylene)-N-methylhydrazine carbothioamide (HPzAm4M), respectively. (2Z,N‧E)-N‧-(4-Oxothiazolidin-2-ylidene)pyrazine-2-carbohydrazonamide (HPzAmot, 5) and (2Z,N‧E)-N‧-(3-methyl-4-oxothiazolidin-2-ylidene)pyrazine-2-carbohydrazonamide (MPzAmot, 7) have been synthesized from these thiosemicarbazones with chloroacetic or bromoacetic acids, using a conventional synthetic methodology and microwave-assisted organic reaction enhancement. The crystal structures of the thiosemicarbazones and their solvates [HPzAm4DHṡ1/2 MeOH (1), HPzAm4DHṡH2O (2), HPzAm4M (3), HPzAm4Mṡ2H2O (4)] and the 1,3-thiazolidin-4-ones (5 and 7) have been studied by X-ray diffractometry. All of the compounds were characterized by elemental analysis, mass spectrometry, FT-IR and 1H and 13C NMR spectroscopy. Several by-products have also been isolated in a crystalline form, namely 3-((Z,E)-N‧-(4-oxothiazolidin-2-ylidene)carbamohydrazonium-yl)pyrazin-1-ium dibromide monohydrate, (H3PzAmot)Br2ṡH2O (6), 2-((5-(pyrazin-2-yl)-1H-1,2,4-triazol-3-yl)thio)acetic acid, (H2Pz124ttAc) (8), 2-amino-5-(pyrazin-2-yl)-1,3,4-thiadiazol-3-ium chloride monohydrate, (HPz134tda)ClṡH2O (9), and 2-(methylamino)-5-(pyrazin-2-yl)-1,3,4-thiadiazol-3-ium chloride N-methyl-5-(pyrazin-2-yl)-1,3,4-thiadiazol-2-amine solvate, (HMPz134tda)Clṡ(MPz134tda) (10). The structures of these compounds were also analyzed by X-ray diffractometry. The microwave-assisted organic reaction method for synthesis is easy, convenient, and ecofriendly when compared to the traditional synthetic methods. Crystal analysis revealed that the compounds have extended 3D supramolecular networks through high levels of H-bonding and weak molecular interactions between the molecular moieties and solvent molecules. The novel synthons, which are

  3. Effect of antimony on the microbial growth and the activities of soil enzymes.

    PubMed

    An, Youn-Joo; Kim, Minjin

    2009-02-01

    The effects of antimony (Sb) on microbial growth inhibition and activities of soil enzymes were investigated in the present study. Test bacterial species were Escherichia coli, Bacillus subtilis and Streptococcus aureus. Among the microorganisms tested, S. aureus was the most sensitive. The 50% effects on the inhibition of specific growth rate of E. coli, B. subtilis, and, S. aureus were 555, 18.4, and 15.8 mg Sb L(-1), respectively. A silt loam soil was amended with antimony and incubated in a controlled condition. Microbial activities of dehydrogenase, acid phosphatase (P cycle), arylsulfatase (S cycle), beta-glucosidase (C cycle), urease (N cycle), and fluorescein diacetate hydrolase in soil were measured. Activities of urease and dehydrogenase were related with antimony and can be an early indication of antimony contamination. The maximum increase in soil urease activity by antimony was up to 168% after 3d compared with the control. The activities of other four enzymes (acid phosphatase, fluorescein diacetate hydrolase, arylsulfatase and ss-glucosidase) were less affected by antimony. This study suggested that antimony affects nitrogen cycle in soil by changing urease activity under the neutral pH, however, soil enzyme activities may not be a good protocol due to their complex response patterns to antimony pollution.

  4. A green synthesis route for the phase and size tunability of copper antimony sulfide nanocrystals with high yield

    NASA Astrophysics Data System (ADS)

    Chen, Keqiang; Zhou, Jing; Chen, Wen; Chen, Qiao; Zhou, Peng; Liu, Yueli

    2016-02-01

    Until now, it is a great challenge for the controllable synthesis of copper antimony sulfide (CAS) nanocrystals (NCs), as the reactivity of precursors is quite difficult to be controlled during the synthesis process. In the present work, a novel solution-based method is proposed to synthesize CAS NCs by choosing N,N'-diphenylthiourea as the sulfide precursor, which is favorable for balancing the relative reactivity of Cu and Sb ions. It is found that three phases (CuSbS2, Cu12Sb4S13 and Cu3SbS4) of CAS NCs with size tunability were successfully synthesized for the first time. To the best of our knowledge, the lowest reaction temperature of 110 °C and the highest yield over 90% for CAS NCs were also achieved for the first time, which may be considered to be a green synthesis route compared with other conventional methods. Optical properties indicate that the as-prepared CAS NCs have strong optical absorption in the visible light region of the solar spectrum, and we also observed the band gap tunability of CuSbS2 and Cu3SbS4 materials for the first time.Until now, it is a great challenge for the controllable synthesis of copper antimony sulfide (CAS) nanocrystals (NCs), as the reactivity of precursors is quite difficult to be controlled during the synthesis process. In the present work, a novel solution-based method is proposed to synthesize CAS NCs by choosing N,N'-diphenylthiourea as the sulfide precursor, which is favorable for balancing the relative reactivity of Cu and Sb ions. It is found that three phases (CuSbS2, Cu12Sb4S13 and Cu3SbS4) of CAS NCs with size tunability were successfully synthesized for the first time. To the best of our knowledge, the lowest reaction temperature of 110 °C and the highest yield over 90% for CAS NCs were also achieved for the first time, which may be considered to be a green synthesis route compared with other conventional methods. Optical properties indicate that the as-prepared CAS NCs have strong optical absorption in the

  5. Identification of Semicarbazones, Thiosemicarbazones and Triazine Nitriles as Inhibitors of Leishmania mexicana Cysteine Protease CPB

    PubMed Central

    Schröder, Jörg; Noack, Sandra; Marhöfer, Richard J.; Mottram, Jeremy C.; Coombs, Graham H.; Selzer, Paul M.

    2013-01-01

    Cysteine proteases of the papain superfamily are present in nearly all eukaryotes. They play pivotal roles in the biology of parasites and inhibition of cysteine proteases is emerging as an important strategy to combat parasitic diseases such as sleeping sickness, Chagas’ disease and leishmaniasis. Homology modeling of the mature Leishmania mexicana cysteine protease CPB2.8 suggested that it differs significantly from bovine cathepsin B and thus could be a good drug target. High throughput screening of a compound library against this enzyme and bovine cathepsin B in a counter assay identified four novel inhibitors, containing the warhead-types semicarbazone, thiosemicarbazone and triazine nitrile, that can be used as leads for antiparasite drug design. Covalent docking experiments confirmed the SARs of these lead compounds in an effort to understand the structural elements required for specific inhibition of CPB2.8. This study has provided starting points for the design of selective and highly potent inhibitors of L. mexicana cysteine protease CPB that may also have useful efficacy against other important cysteine proteases. PMID:24146999

  6. Benzaldehyde Thiosemicarbazone Derived from Limonene Complexed with Copper Induced Mitochondrial Dysfunction in Leishmania amazonensis

    PubMed Central

    Britta, Elizandra Aparecida; Barbosa Silva, Ana Paula; Ueda-Nakamura, Tânia; Dias-Filho, Benedito Prado; Silva, Cleuza Conceição; Sernaglia, Rosana Lázara; Nakamura, Celso Vataru

    2012-01-01

    Background Leishmaniasis is a major health problem that affects more than 12 million people. Treatment presents several problems, including high toxicity and many adverse effects, leading to the discontinuation of treatment and emergence of resistant strains. Methodology/Principal Findings We evaluated the in vitro antileishmanial activity of benzaldehyde thiosemicarbazone derived from limonene complexed with copper, termed BenzCo, against Leishmania amazonensis. BenzCo inhibited the growth of the promastigote and axenic amastigote forms, with IC50 concentrations of 3.8 and 9.5 µM, respectively, with 72 h of incubation. Intracellular amastigotes were inhibited by the compound, with an IC50 of 10.7 µM. BenzCo altered the shape, size, and ultrastructure of the parasites. Mitochondrial membrane depolarization was observed in protozoa treated with BenzCo but caused no alterations in the plasma membrane. Additionally, BenzCo induced lipoperoxidation and the production of mitochondrial superoxide anion radicals in promastigotes and axenic amastigotes of Leishmania amazonensis. Conclusion/Significance Our studies indicated that the antileishmania activity of BenzCo might be associated with mitochondrial dysfunction and oxidative damage, leading to parasite death. PMID:22870222

  7. Structural and biological evaluation of some metal complexes of vanillin-4N-(2-pyridyl) thiosemicarbazone

    NASA Astrophysics Data System (ADS)

    Yousef, T. A.; Abu El-Reash, G. M.; Al-Jahdali, M.; El-Rakhawy, El-Bastawesy R.

    2013-12-01

    The synthesis and characterization of Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Hg(II) and U(VI)O2 complexes of vanillin-4N-(2-pyridyl) thiosemicarbazone (H2PVT) are reported. Theoretical calculations have been performed to obtain IR spectra of ligand and its complexes using AM1, Zindo/1, MM+ and PM3, methods. The Schiff base and its metal complexes have been screened for antibacterial Pseudomonas aeruginosa, Escherichia coli, Bacillus subtilis and Staphylococcus saprophyticus. H2VPT shows no apparent digestion effect on the egg albumin while Mn(II), Hg(II) and Cu(II) complexes exhibited a considerable digestion effect following the order Cu(II) > Mn(II) > Hg(II). Moreover, Ni(II) and Co(II) complexes revealed strong digestion effect. Fe(II), Mn(II), Cu(II), Zn(II) and Ni(II) acted as metal co- SOD enzyme factors, which are located in different compartments of the cell.

  8. Spectroscopic analysis, AIM, NLO and VCD investigations of acetaldehyde thiosemicarbazone using quantum mechanical simulations

    NASA Astrophysics Data System (ADS)

    Moorthy, N.; Prabakar, P. C. Jobe; Ramalingam, S.; Govindarajan, M.; Gnanamuthu, S. Joshua; Pandian, G. V.

    2016-08-01

    The prepared Acetaldehyde thiosemicarbazone (ATSC) have been investigated by both the experimental and theoretical methods; through this work, the essentiality of elucidation of molecular fragments source linear and non-linear optical properties was explored. The stability of the structure and entire calculations have been performed on HF and B3LYP methods with 6-311++G(d,p) level of basis set. The Mulliken charge profile, electronic, optical and hyper polarizability analyses have been carried out in order to evaluate nonlinear optical (NLO) performance of the present compound. The exact optical location of the ATSC was determined by executing UV-Visible calculations on TDSCF method. The existence of the molecular group for the inducement and tuning of NLO properties were thoroughly investigated by performing fundamental vibrational investigation. The optical energy transformation among frontier molecular levels has been described in UV-Visible region. The Gibbs energy coefficient of thermodynamic functions was monitored in different temperature and it was found constant irrespective of temperatures. The appearance of different chemical environment of H and C was monitored from the 1H and 13C NMR spectra. The vibrational optical polarization characteristics with respect to molecular composition in the compound have been studied by VCD spectrum. The bond critical point, Laplacian of electron density, electron kinetic energy density and total electron energy density have calculated and analysed using AIM study.

  9. The Hydrothermal Chemistry of Gold, Arsenic, Antimony, Mercury and Silver

    SciTech Connect

    Bessinger, Brad; Apps, John A.

    2003-03-23

    A comprehensive thermodynamic database based on the Helgeson-Kirkham-Flowers (HKF) equation of state was developed for metal complexes in hydrothermal systems. Because this equation of state has been shown to accurately predict standard partial molal thermodynamic properties of aqueous species at elevated temperatures and pressures, this study provides the necessary foundation for future exploration into transport and depositional processes in polymetallic ore deposits. The HKF equation of state parameters for gold, arsenic, antimony, mercury, and silver sulfide and hydroxide complexes were derived from experimental equilibrium constants using nonlinear regression calculations. In order to ensure that the resulting parameters were internally consistent, those experiments utilizing incompatible thermodynamic data were re-speciated prior to regression. Because new experimental studies were used to revise the HKF parameters for H2S0 and HS-1, those metal complexes for which HKF parameters had been previously derived were also updated. It was found that predicted thermodynamic properties of metal complexes are consistent with linear correlations between standard partial molal thermodynamic properties. This result allowed assessment of several complexes for which experimental data necessary to perform regression calculations was limited. Oxygen fugacity-temperature diagrams were calculated to illustrate how thermodynamic data improves our understanding of depositional processes. Predicted thermodynamic properties were used to investigate metal transport in Carlin-type gold deposits. Assuming a linear relationship between temperature and pressure, metals are predicted to predominantly be transported as sulfide complexes at a total aqueous sulfur concentration of 0.05 m. Also, the presence of arsenic and antimony mineral phases in the deposits are shown to restrict mineralization within a limited range of chemical conditions. Finally, at a lesser aqueous sulfur

  10. Inhibition of ABC Transporters Abolishes Antimony Resistance in Leishmania Infection▿

    PubMed Central

    Mookerjee Basu, Jayati; Mookerjee, Ananda; Banerjee, Rajdeep; Saha, Manik; Singh, Subhankar; Naskar, Ksudiram; Tripathy, Gayetri; Sinha, Prabhat K.; Pandey, Krishna; Sundar, Shyam; Bimal, Sanjeev; Das, Pradip K.; Choudhuri, Soumitra K.; Roy, Syamal

    2008-01-01

    The emergence of antimony (Sb) resistance has jeopardized the treatment of visceral leishmaniasis in various countries. Previous studies have considered the part played by leishmanial parasites in antimony resistance, but the involvement of host factors in the clinical scenario remained to be investigated. Here we show that unlike infection with Sb-sensitive (Sbs) Leishmania donovani, infection with Sb-resistant (Sbr) L. donovani induces the upregulation of multidrug resistance-associated protein 1 (MRP1) and permeability glycoprotein (P-gp) in host cells, resulting in a nonaccumulation of intracellular Sb following treatment with sodium antimony gluconate (SAG) favoring parasite replication. The inhibition of MRP1 and P-gp with resistance-modifying agents such as lovastatin allows Sb accumulation and parasite killing within macrophages and offers protection in an animal model in which infection with Sbr L. donovani is otherwise lethal. The occurrence of a similar scenario in clinical cases is supported by the findings that unlike monocytes from SAG-sensitive kala-azar (KA) patients, monocytes from SAG-unresponsive KA patients overexpress P-gp and MRP1 and fail to accumulate Sb following in vitro SAG treatment unless pretreated with inhibitors of ABC transporters. Thus, the expression status of MRP1 and P-gp in blood monocytes may be used as a diagnostic marker for Sb resistance and the treatment strategy can be designed accordingly. Our results also indicate that lovastatin, which can inhibit both P-gp and MRP1, might be beneficial for reverting Sb resistance in leishmaniasis as well as drug resistance in other clinical situations, including cancer. PMID:18056276

  11. Binuclear ruthenium(III) bis(thiosemicarbazone) complexes: synthesis, spectral, electrochemical studies and catalytic oxidation of alcohol.

    PubMed

    Mohamed Subarkhan, M; Ramesh, R

    2015-03-05

    A new series of binuclear ruthenium(III) thiosemicarbazone complexes of general formula [(EPh3)2(X)2Ru-L-Ru(X)2(EPh3)2] (where E=P or As; X=Cl or Br; L=NS chelating bis(thiosemicarbazone ligands) has been synthesized and characterized by analytical and spectral (FT-IR, UV-Vis and EPR). IR spectra show that the thiosemicarbazones behave as monoanionic bidentate ligands coordinating through the azomethine nitrogen and thiolate sulphur. The electronic spectra of the complexes indicate that the presence of d-d and intense LMCT transitions in the visible region. The complexes are paramagnetic (low spin d(5)) in nature and all the complexes show rhombic distortion around the ruthenium ion with three different 'g' values (gx≠gy≠gz) at 77K. All the complexes are redox active and exhibit an irreversible metal centered redox processes (Ru(III)-Ru(III)/Ru(IV)-Ru(IV); Ru(III)-Ru(III)/Ru(II)-Ru(II)) within the potential range of 0.38-0.86V and -0.39 to -0.66 V respectively, versus Ag/AgCl. Further, the catalytic efficiency of one of the complexes [Ru2Cl2(AsPh3)4(L1)] (4) has been investigated in the case of oxidation of primary and secondary alcohols into their corresponding aldehydes and ketones in the presence of N-methylmorpholine-N-oxide(NMO) as co-oxidant. The formation of high valent Ru(V)O species is proposed as catalytic intermediate for the catalytic cycle.

  12. Electrostatically defined silicon quantum dots with counted antimony donor implants

    SciTech Connect

    Singh, M. Luhman, D. R.; Lilly, M. P.; Pacheco, J. L.; Perry, D.; Garratt, E.; Ten Eyck, G.; Bishop, N. C.; Wendt, J. R.; Manginell, R. P.; Dominguez, J.; Pluym, T.; Bielejec, E.; Carroll, M. S.

    2016-02-08

    Deterministic control over the location and number of donors is crucial to donor spin quantum bits (qubits) in semiconductor based quantum computing. In this work, a focused ion beam is used to implant antimony donors in 100 nm × 150 nm windows straddling quantum dots. Ion detectors are integrated next to the quantum dots to sense the implants. The numbers of donors implanted can be counted to a precision of a single ion. In low-temperature transport measurements, regular Coulomb blockade is observed from the quantum dots. Charge offsets indicative of donor ionization are also observed in devices with counted donor implants.

  13. Synthetic carbon precursor materials

    SciTech Connect

    Frame, B.J.

    1986-03-01

    Synthetic carbon precursor systems offer advantages over natural petroleum and coal-tar pitch precursors in that they can reproducibly provide a material with a known and uniform composition. They also permit controlled modifications of the derived carbon's properties through variations in the precursor's properties and processing conditions. Extensive research efforts at Oak Ridge have been directed toward the production and characterization of synthetic carbon precursors and the correlations that exist between carbon precursor properties and the properties of the ultimate carbon. This report describes how synthetic carbon precursors can be used to tailor and develop reproducible carbon structures for advanced materials applications. The potential and capability for performing carbon material development at Oak Ridge is also described.

  14. Synthesis and cytotoxic activity of N-substituted thiosemicarbazones of 3-(3,4-methylenedioxy)phenylpropanal.

    PubMed

    Joselice e Silva, M; Alves, A J; Do Nascimento, S C

    1998-03-01

    Five new N-substituted thiosemicarbazones of 3-(3,4-methylenedioxy)phenylpropanal were synthesized. Safrole, a natural product obtained from sassafras oil (Ocotea pretiosa), was oxidized to alcohol using BH3-THF and H2O2, followed by oxidation to aldehyde using pyridinium dichromate (PDC) and condensation with five N-substituted derivatives of thiosemicarbazide. Tests were performed to evaluate the cytotoxic activity with continuous chain KB cells (epidermoide carcinoma of the floor of the mouth). Compounds 5 and 6 showed IC50 values of 1.5 and 4.6 micrograms/ml, respectively.

  15. Structural requirement(s) of N-phenylthioureas and benzaldehyde thiosemicarbazones as inhibitors of melanogenesis in melanoma B 16 cells.

    PubMed

    Thanigaimalai, P; Hoang, Tuan Anh Le; Lee, Ki-Cheul; Bang, Seong-Cheol; Sharma, Vinay K; Yun, Cheong-Yong; Roh, Eunmiri; Hwang, Bang-Yeon; Kim, Youngsoo; Jung, Sang-Hun

    2010-05-01

    In order to define the structural requirements of phenylthiourea (PTU), a series of thiourea and thiosemicarbazone analogs were prepared and evaluated as inhibitors of melanogenesis in melanoma B16 cells. The most potent analog was 2-(4-tert-butylbenzylidene)hydrazinecarbothioamide (1u) with an IC(50) value of 2.7 microM in inhibition of melanogenesis. The structure for potent inhibitory activity of these derivatives are required with the direct connection of pi-planar structure to thiourea without steric hinderance in PTU derivatives and the hydrophobic substituent at para position in case of semicarbazones.

  16. Targeting triple negative breast cancer cells by N3-substituted 9,10-Phenanthrenequinone thiosemicarbazones and their metal complexes

    NASA Astrophysics Data System (ADS)

    Afrasiabi, Zahra; Stovall, Preston; Finley, Kristen; Choudhury, Amitava; Barnes, Charles; Ahmad, Aamir; Sarkar, Fazlul; Vyas, Alok; Padhye, Subhash

    2013-10-01

    Novel N3-substituted 9,10-Phenanthrenequinone thiosemicarbazones and their copper, nickel and palladium complexes are structurally characterized and reported along with the single crystal X-ray structures of three ligands and one nickel complex. All compounds were evaluated for their antiproliferative potential against Triple Negative Breast Cancer (TNBC) cells which have poor prognosis and no effective drugs to treat with. All compounds exhibited antiproliferative activity against these cells. Among the metal complexes evaluated, redox active copper complexes were found to be more potent. The possible mechanism for such enhanced activity can be attributed to the generation of oxidative stress, which was amenable for targeting through metal complexation.

  17. Simultaneous lead and antimony immobilization in shooting range soil by a combined application of hydroxyapatite and ferrihydrite.

    PubMed

    Ogawa, Shouhei; Katoh, Masahiko; Sato, Takeshi

    2015-01-01

    This study investigated whether a combined application of hydroxyapatite and ferrihydrite could immobilize lead and antimony in shooting range soil in which the level of lead contamination is markedly higher than that of antimony. In addition, we evaluated the stability of lead and antimony immobilized by the combined application with varying soil pH. The levels of water-soluble lead and antimony for the combined application were lower than those of single applications of hydroxyapatite or ferrihydrite, indicating that the combined application could suppress the levels of water-soluble lead and antimony by 99.9% and 95.5%, respectively, as compared with the levels in shooting range soil without immobilization material. The amounts of residual lead and amorphous Fe/Al oxide-bound antimony fractions in sequential extraction increased with a decrease in the exchangeable and carbonate lead fractions as well as in non-specifically bound and specifically bound antimony fractions. The alteration of lead and antimony phases to chemically more stable ones as a result of the combined application would result in the suppression of their mobility. The stability of immobilized lead and antimony in the combined application was equal to that of lead with a single application of hydroxyapatite and that of antimony with a single application of ferrihydrite within neutral to alkaline pH conditions, respectively. Therefore, this study suggests that the combined application of hydroxyapatite and ferrihydrite can simultaneously immobilize lead and antimony in shooting range soil with neutral to alkaline pH.

  18. New Iminodiacetate-Thiosemicarbazone Hybrids and Their Copper(II) Complexes Are Potential Ribonucleotide Reductase R2 Inhibitors with High Antiproliferative Activity.

    PubMed

    Zaltariov, Mirela F; Hammerstad, Marta; Arabshahi, Homayon J; Jovanović, Katarina; Richter, Klaus W; Cazacu, Maria; Shova, Sergiu; Balan, Mihaela; Andersen, Niels H; Radulović, Siniša; Reynisson, Jóhannes; Andersson, K Kristoffer; Arion, Vladimir B

    2017-03-20

    As ribonucleotide reductase (RNR) plays a crucial role in nucleic acid metabolism, it is an important target for anticancer therapy. The thiosemicarbazone Triapine is an efficient R2 inhibitor, which has entered ∼20 clinical trials. Thiosemicarbazones are supposed to exert their biological effects through effectively binding transition-metal ions. In this study, six iminodiacetate-thiosemicarbazones able to form transition-metal complexes, as well as six dicopper(II) complexes, were synthesized and fully characterized by analytical, spectroscopic techniques (IR, UV-vis; (1)H and (13)C NMR), electrospray ionization mass spectrometry, and X-ray diffraction. The antiproliferative effects were examined in several human cancer and one noncancerous cell lines. Several of the compounds showed high cytotoxicity and marked selectivity for cancer cells. On the basis of this, and on molecular docking calculations one lead dicopper(II) complex and one thiosemicarbazone were chosen for in vitro analysis as potential R2 inhibitors. Their interaction with R2 and effect on the Fe(III)2-Y· cofactor were characterized by microscale thermophoresis, and two spectroscopic techniques, namely, electron paramagnetic resonance and UV-vis spectroscopy. Our findings suggest that several of the synthesized proligands and copper(II) complexes are effective antiproliferative agents in several cancer cell lines, targeting RNR, which deserve further investigation as potential anticancer drugs.

  19. Improved antiparasitic activity by incorporation of organosilane entities into half-sandwich ruthenium(II) and rhodium(III) thiosemicarbazone complexes.

    PubMed

    Adams, Muneebah; de Kock, Carmen; Smith, Peter J; Land, Kirkwood M; Liu, Nicole; Hopper, Melissa; Hsiao, Allyson; Burgoyne, Andrew R; Stringer, Tameryn; Meyer, Mervin; Wiesner, Lubbe; Chibale, Kelly; Smith, Gregory S

    2015-02-07

    A series of ferrocenyl- and aryl-functionalised organosilane thiosemicarbazone compounds was obtained via a nucleophilic substitution reaction with an amine-terminated organosilane. The thiosemicarbazone (TSC) ligands were further reacted with either a ruthenium dimer [(η(6-i)PrC6H4Me)Ru(μ-Cl)Cl]2 or a rhodium dimer [(Cp*)Rh(μ-Cl)Cl]2 to yield a series of cationic mono- and binuclear complexes. The thiosemicarbazone ligands, as well as their metal complexes, were characterised using NMR and IR spectroscopy, and mass spectrometry. The molecular structure of the binuclear ruthenium(ii) complex was determined by single-crystal X-ray diffraction analysis. The thiosemicarbazones and their complexes were evaluated for their in vitro antiplasmodial activities against the chloroquine-sensitive (NF54) and chloroquine-resistant (Dd2) Plasmodium falciparum strains, displaying activities in the low micromolar range. Selected compounds were screened for potential β-haematin inhibition activity, and it was found that two Rh(iii) complexes exhibited moderate to good inhibition. Furthermore, the compounds were screened for their antitrichomonal activities against the G3 Trichomonas vaginalis strain, revealing a higher percentage of growth inhibition for the ruthenium and rhodium complexes over their corresponding ligand.

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

    NASA Technical Reports Server (NTRS)

    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.

  1. Antimony sulphide, an absorber layer for solar cell application

    NASA Astrophysics Data System (ADS)

    Ali, N.; Hussain, Arshad; Ahmed, R.; Shamsuri, W. N. Wan; Shaari, A.; Ahmad, N.; Abbas, S. M.

    2016-01-01

    Replacement of the toxic, expensive and scarce materials with nontoxic, cheap and earth-abundant one, in solar cell absorber layer, is immensely needed to realize the vision of green and sustainable energy. Two-micrometre-thin antimony sulphide film is considered to be adequate as an absorbing layer in solar cell applications. In this paper, we synthesize antimony sulphide thin films on glass substrate by physical vapour deposition technique, and the obtained films were then annealed at different temperatures (150-250 °C). The as-deposited and annealed samples were investigated for structural and optoelectronic properties using different characterization techniques. The X-ray diffraction analysis showed that the annealed samples were polycrystalline with Sb2S3 phase, while the as-deposited sample was amorphous in nature. The optical properties are measured via optical ellipsometric techniques. The measured absorbance of the film is adequately high, and every photon is found to be absorbed in visible and NIR range. The conductivity type of the films measured by hot-point probe technique is determined to be p-type. The optical band gap of the resulted samples was in the range (2.4-1.3 eV) for the as-deposited and annealed films.

  2. Antimony contamination and its effect on Trifolium plants

    NASA Astrophysics Data System (ADS)

    Corrales, Isabel; Barceló, Juan; Bech, Jaume; Poschenrieder, Charlotte

    2014-05-01

    Antimony is not an essential element and soil Sb contents usually are low.However, soil contamination by Sb has increased in the last years due to the human activities (combustion of fossil fuels, mining, waste incineration, smelting, shooting and road traffic). The main objective of this work was to study the effect of different concentrations of antimony (KSb(OH)6) in order to evaluate the effect on growth and Sb uptake on Trifolium pratense cv. Milvus and Trifolium repens. Our results show that Sb accumulated both in roots and shoots of clover without any negative effect on root growth, cellular viability and lipid peroxidation. This absence of toxicity sympthoms in clover plants could be very dangerous because Sb can be inadvertedly incorporated into the trophic chain causing toxic effects both in animals and humans. The absence of toxic effects on plants does not seem to be due to detoxification by phytochelatins because the use of the gamma-glutamylcysteine synthetase inhibitor, L-buthionine-[S,R]-sulphoximine (BSO) did not enhance Sb toxicity to plants. (Supported by the Spanish MICINN project BFU2010-14873)

  3. Thermoelectric Micro-Refrigerator Based on Bismuth/Antimony Telluride

    NASA Astrophysics Data System (ADS)

    Dang, Linh Tuan; Dang, Tung Huu; Nguyen, Thao Thi Thu; Nguyen, Thuat Tran; Nguyen, Hue Minh; Nguyen, Tuyen Viet; Nguyen, Hung Quoc

    2017-03-01

    Thermoelectric micro-coolers based on bismuth telluride (Bi2Te3) and antimony telluride (Sb2Te3) are important in many practical applications thanks to their compactness and fluid-free circulation. In this paper, we studied thermoelectric properties of bismuth/antimony telluride (Bi/SbTe) thin films prepared by the thermal co-evaporation method, which yielded among the best thermoelectric quality. Different co-evaporation conditions such as deposition flux ratio of materials and substrate temperature during deposition were investigated to optimize the thermoelectric figure␣of merit of these materials. Micron-size refrigerators were designed and fabricated using standard lithography and etching technique. A three-layer structure was introduced, including a p-type layer, an n-type layer and an aluminum layer. Next to the main cooler, a pair of smaller Bi/SbTe junctions was used as a thermocouple to directly measure electron temperature of the main device. Etching properties of the thermoelectric materials were investigated and optimized to support the fabrication process of the micro-refrigerator. We discuss our results and address possible applications.

  4. Antimony in the environment: A review focused on natural waters. III. Microbiota relevant interactions

    NASA Astrophysics Data System (ADS)

    Filella, Montserrat; Belzile, Nelson; Lett, Marie-Claire

    2007-02-01

    Antimony is ubiquitously present in the environment as a result of natural processes and human activities. Antimony is not considered to be an essential element for plants or animals. In this third review paper on the occurrence of antimony in natural waters, the interactions of antimony with microbiota are discussed in relation to its fate in natural waters. This paper covers the following aspects: occurrence in microbiota, uptake transport mechanisms, pathways of Sb(III) removal from cells involved in antimony tolerance, oxidation and reduction of antimony by living organisms, phytochelatin induction and biomethylation. This review is based on a careful and systematic examination of a comprehensive collection of papers on the above mentioned aspects of the subject. All data are quoted from the original sources. Relatively little existing information falls within the strict scope of this review and, when relevant, discussion on the interactions of antimony with reference microorganisms, such as Escherichia coli, Saccharomyces cerevisiae and different protozoan parasites of the genus Leishmania, has been included.

  5. Immobilization of antimony waste slag by applying geopolymerization and stabilization/solidification technologies.

    PubMed

    Salihoglu, Güray

    2014-11-01

    During the processing of antimony ore by pyrometallurgical methods, a considerable amount of slag is formed. This antimony waste slag is listed by the European Union as absolutely hazardous waste with a European Waste Catalogue code of 10 08 08. Since the levels of antimony and arsenic in the leachate of the antimony waste slag are generally higher than the landfilling limits, it is necessary to treat the slag before landfilling. In this study, stabilization/solidification and geopolymerization technologies were both applied in order to limit the leaching potential of antimony and arsenic. Different combinations ofpastes by using Portland cement, fly ash, clay, gypsum, and blast furnace slag were prepared as stabilization/solidification or geopoljymer matrixes. Sodium silicate-sodium hydroxide solution and sodium hydroxide solution at 8 M were used as activators for geopolymer samples. Efficiencies of the combinations were evaluated in terms of leaching and unconfined compressive strength. None of the geopolymer samples prepared with the activators yielded arsenic and antimony leaching below the regulatory limit at the same time, although they yielded high unconfined compressive strength levels. On the other hand, the stabilization/solidification samples prepared by using water showed low leaching results meeting the landfilling criteria. Use of gypsum as an additive was found to be successful in immobilizing the arsenic and antimony.

  6. Polyimide Precursor Solid Residuum

    NASA Technical Reports Server (NTRS)

    Weiser, Erik S. (Inventor); St.Clair, Terry L. (Inventor); Echigo, Yoshiaki (Inventor); Kaneshiro, Hisayasu (Inventor)

    2001-01-01

    A polyimide precursor solid residuum is an admixture of an aromatic dianhydride or derivative thereof and an aromatic diamine or derivative thereof plus a complexing agent, which is complexed with the admixture by hydrogen bonding. The polyimide precursor solid residuum is effectively employed in the preparation of polyimide foam and the fabrication of polyimide foam structures.

  7. New Oxidovanadium Complexes Incorporating Thiosemicarbazones and 1, 10-Phenanthroline Derivatives as DNA Cleavage, Potential Anticancer Agents, and Hydroxyl Radical Scavenger.

    PubMed

    Ying, Peng; Zeng, Pengfei; Lu, Jiazheng; Chen, Hongyuan; Liao, Xiangwen; Yang, Ning

    2015-10-01

    Four novel oxidovanadium(IV) complexes, [VO(hntdtsc)(PHIP)] (1) (hntdtsc = 2-hydroxy-1-naphthaldehyde thiosemicarbazone, PHIP= 2-phenyl-imidazo[4,5-f]1,10-phenanthroline), [VO(hntdtsc)(DPPZ)](2)(DPPZ= dipyrido[3,2-a:2',3'-c]phenazine), [VO(satsc)(PHIP)](3) (satsc=salicylaldehyde thiosemicarbazone), and [VO(satsc)(DPPZ)](4), have been prepared and characterized. The chemical nuclease activities and photocleavage reactions of the complexes were tested. All four complexes can efficiently cleave pBR322 DNA, and complex 1 has the best cleaving ability. The antitumor properties of these complexes were examined with three different tumor cell lines using MTT assay. Their antitumor mechanism has been analyzed using cell cycle analysis, fluorescence microscopy of apoptosis, and Annexin V-FITC/PI assay. The results showed that the growth of human neuroblastoma (SH-SY5Y, SK-N-SH) and human breast adenocarcinoma (MCF-7) cells were inhibited significantly with very low IC50 values. Complex 1 was found to be the most potent antitumor agent among the four complexes. It can cause G0/G1 phase arrest of the cell cycle and exhibited significant induced apoptosis in SK-N-SH cells and displayed typical morphological apoptotic characteristics. In addition, they all displayed reasonable abilities to scavenge hydroxyl radical, and complex 1 was the best inhibitor.

  8. Platinum-based complexes of bioactive 3-(5-nitrofuryl)acroleine thiosemicarbazones showing anti-Trypanosoma cruzi activity.

    PubMed

    Vieites, Marisol; Otero, Lucía; Santos, Diego; Olea-Azar, Claudio; Norambuena, Ester; Aguirre, Gabriela; Cerecetto, Hugo; González, Mercedes; Kemmerling, Ulrike; Morello, Antonio; Diego Maya, Juan; Gambino, Dinorah

    2009-03-01

    Eight new platinum(II) complexes with 3-(5-nitrofuryl)acroleine thiosemicarbazones showing anti-trypanosomal activity were synthesized, characterized and in vitro evaluated. Most of the complexes showed IC(50) values in the micromolar range against two different strains of Trypanosoma cruzi, causative agent of Chagas disease (American Trypanosomiasis). In addition, most of the newly developed complexes, together with the analogous platinum 5-nitrofuraldehyde containing thiosemicarbazones previously reported, resulted more active than the reference trypanocidal drug nifurtimox on the infective trypomastigote form of the parasite. Their capacity to produce free radicals that could lead to parasite death was evaluated by ESR experiments in the parasite and by respiration measurements. Compounds were tested for their DNA interaction ability. Results showed that some of the compounds could act as dual inhibitors in the parasite, through production of toxic free radicals and interaction with DNA. All the results were compared with those previously reported for the free ligands, the analogous palladium(II) compounds and the previously reported series of platinum(II) compounds.

  9. α(N)-Heterocyclic Thiosemicarbazones: Iron Chelators That Are Promising for Revival of Gallium in Cancer Chemotherapy.

    PubMed

    Cao, Shuhong; Chen, Xiahui; Chen, Ligen; Chen, Jingwen

    2016-03-10

    The metal-based drugs have gained increasing attention in the fight against cancer. Ga(III) in the form of inorganic salts has demonstrated efficacy in the treatment of a number of malignancies in experimental animals and humans, and has therefore attracted considerable pharmaceutical interest. However, the poor hydrolytic stability of Ga(III) in physiological medium owing to its property of hard Lewis acid prevents its widespread use in systemic cancer chemotherapy. Complexation of suitable chelators capable of stabilising Ga(III) against hydrolysis affords an opportunity for overcoming this drawback. Thiosemicarbazone (TSC) derivatives, a class of well-studied iron chelators featuring softer donor sulfur, also were evaluated to possess antineoplastic activities in an arrary of tumour cell lines. The structural modifications can affect the activities of TSCs, and related structure-activity relationships (SAR) have been studied over these years. Combination of Ga(III) and TSCs that are both pharmaceutically active has proved to exert synergistic effects of each component in one compound in most cases, and may produce more potent Ga(III) drugs. In this review, the SAR of α(N)-heterocyclic thiosemicarbazone (HCT) analogues, a family of TSCs, were scrupulously surveyed, and the effect of Ga(III) complexation on their anticancer activity sparsely reported in literature was comparatively examined, in order to stimulate further advances in the field of gallium-based anticancer drugs.

  10. Biologically active thiosemicarbazone Fe chelators and their reactions with ferrioxamine B and ferric EDTA; a kinetic study.

    PubMed

    Bernhardt, Paul V; Martínez, Manuel; Rodríguez, Carlos; Vazquez, Marta

    2012-02-21

    The Fe(III) abstraction from Fe(III)/DFO and Fe(III)/EDTA complex systems by thiosemicarbazone ligands derived from 2-acetylpyridine has been studied from a kinetico-mechanistic perspective at relevant pH conditions and at varying temperatures and buffer solutions. The reactions have been found to be extremely dependent on the dominant E/Z isomeric form of the TSC ligands present in the reaction medium. Consequently the isomerisation processes occurring on the free ligands have also been monitored under equivalent conditions. The isomerisation process is found to be acid dependent, despite the absence of protonation under the conditions used, and presumably proceeds via an azo-type tautomer of the ligand. In all cases the existence of outer-sphere interaction processes has been established, both promoting the reactions and producing dead-end complexes. The better oriented forms of the ligands (EZ thiolate) have been found to react faster with the [Fe(HDFO)](+) complex, although for mono-N(4) substituted thiosemicarbazones the process is retarded by the formation of a dead-end outer-sphere complex. A comparison with the abstraction of Fe(III) from [Fe(EDTA)(H(2)O)](-) has also been conducted with significant differences in the kinetic features that implicate keystone outer-sphere interactions which dominate reactivity, even with isomeric forms that are not the best suited for direct complexation.

  11. Comparative evaluation of Bis(thiosemicarbazone)- Biotin and Met-ac-TE3A for tumor imaging

    NASA Astrophysics Data System (ADS)

    Singh, Sweta; Tiwari, Anjani K.; Varshney, Raunak; Mathur, R.; Shukla, Gauri; Bag, N.; Singh, B.; Mishra, Anil K.

    2016-01-01

    2,2‧,2″-(11-(2-((4-mercapto-1-methoxy-1-oxobutan-2-yl)amino)-2-oxoethyl)-1,4,8,11-tetraaza cyclotetradecane-1,4,8-triyl)triacetic acid, Met-ac-TE3A and (E)-N-methyl-2-((E)-3-(2-(2-(5-((3aS,4S,6aR)-2-oxohexahydro-1H-thieno[3,4-d]imidazol-4-yl)pentanoyl)hydrazinecarbono-thioyl)hydrazonobutan-2-ylidene)hydrazinecarbothioamide, Bis(thiosemicarbazone)- Biotin were synthesized and evaluated for imaging application. The pharmacokinetics of these ligands were determined by tracer methods. In vitro human serum stability of 99mTc Met-ac-TE3A/99mTc Bis(thiosemicarbazone)-Biotin after 24 h was found to be 96.5% and 97.0% respectively. Blood kinetics of both ligands in normal rabbits showed biphasic clearance pattern. Ex vivo biodistribution study revealed significant initial tumor uptake and high tumor/muscles ratio which is a pre-requisite condition for a ligand to work as SPECT-radiopharmaceutical for tumor imaging.

  12. Thiosemicarbazones and Phthalyl-Thiazoles compounds exert antiviral activity against yellow fever virus and Saint Louis encephalitis virus.

    PubMed

    Pacca, Carolina Colombelli; Marques, Rafael Elias; Espindola, José Wanderlan P; Filho, Gevânio B O Oliveira; Leite, Ana Cristina Lima; Teixeira, Mauro Martins; Nogueira, Mauricio L

    2017-03-01

    Arboviruses, arthropod-borneviruses, are frequency associated to human outbreak and represent a serious health problem. The genus Flavivirus, such as Yellow Fever Virus (YFV) and Saint Louis Encephalitis Virus (SLEV), are important pathogens with high morbidity and mortality worldwide. In Brazil, YFV is maintained in sylvatic cycle, but many cases are notified annually, despite the efficiency of vaccine. SLEV causes an acute encephalitis and is widely distributed in the Americas. There is no specific antiviral drugs for these viruses, only supporting treatment that can alleviate symptoms and prevent complications. Here, we evaluated the potential anti-YFV and SLEV activity of a series of thiosemicarbazones and phthalyl-thiazoles. Plaque reduction assay, flow cytometry, immunofluorescence and cellular viability were used to test the compounds in vitro. Treated cells showed efficient inhibition of the viral replication at concentrations that presented minimal toxicity to cells. The assays showed that phthalyl-thiazole and phenoxymethyl-thiosemicarbazone reduced 60% of YFV replication and 75% of SLEV replication.

  13. Vibrational, NMR and UV-Visible spectroscopic investigation, VCD and NLO studies on Benzophenone thiosemicarbazone using computational calculations

    NASA Astrophysics Data System (ADS)

    Moorthy, N.; Jobe Prabakar, P. C.; Ramalingam, S.; Periandy, S.; Parasuraman, K.

    2016-04-01

    In order to explore the unbelievable NLO property of prepared Benzophenone thiosemicarbazone (BPTSC), the experimental and theoretical investigation has been made. The theoretical calculations were made using RHF and CAM-B3LYP methods at 6-311++G(d,p) basis set. The title compound contains Cdbnd S ligand which helps to improve the second harmonic generation (SHG) efficiency. The molecule has been examined in terms of the vibrational, electronic and optical properties. The entire molecular behavior was studied by their fundamental IR and Raman wavenumbers and was compared with the theoretical aspect. The molecular chirality has been studied by performing vibrational circular dichroism (circularly polarized infrared radiation). The Mulliken charge levels of the compound ensure the perturbation of atomic charges according to the ligand. The molecular interaction of frontier orbitals emphasizes the modification of chemical properties of the compound through the reaction path. The enormous amount of NLO activity was induced by the Benzophenone in thiosemicarbazone. The Gibbs free energy was evaluated at different temperature and from which the enhancement of chemical stability was stressed. The VCD spectrum was simulated and the optical dichroism of the compound has been analyzed.

  14. Synthesis of thiophene-thiosemicarbazone derivatives and evaluation of their in vitro and in vivo antitumor activities.

    PubMed

    de Oliveira, Jamerson Ferreira; da Silva, Anekécia Lauro; Vendramini-Costa, Débora Barbosa; da Cruz Amorim, Cezar Augusto; Campos, Júlia Furtado; Ribeiro, Amélia Galdino; Olímpio de Moura, Ricardo; Neves, Jorge Luiz; Ruiz, Ana Lúcia Tasca Gois; Ernesto de Carvalho, João; Alves de Lima, Maria do Carmo

    2015-11-02

    A series of thiophene-2-thiosemicarbazones derivatives (5-14) was synthesized, characterized and evaluated for their antitumor activity. They were tested in vitro against human tumor cell lines through the colorimetric method. The results revealed that compounds 7 and 9 were the most effective in inhibiting 50% of the cell growth after 48 h of treatment. As compound 7 showed a potent antiproliferative profile, it has been chosen for further studies in 786-0 cell line by flow cytometry. Treatments with compound 7 (50 μM) induced early phosphatidylserine exposure after 18 h of exposure and this process progressed phosphatidylserine exposure with loss of cell membrane integrity after 24 h of treatment, suggesting a time-dependent cell death process. Regarding the cell cycle profile, no changes were observed after treatment with compound 7 (25 μM), suggesting a mechanism of cell death independent on the cell cycle. The in vivo studies show that compound 7 possess low acute toxicity, being the doses of 30-300 mgKg(-1) chosen for studies in Ehrlich solid tumor model in mice. All doses were able to inhibit tumor development being the lowest one the most effective. Our findings highlight thiophene-2-thiosemicarbazones as a promising class of compounds for further studies concerning new anticancer therapies.

  15. In vitro cytotoxic, antibacterial, antifungal and urease inhibitory activities of some N4- substituted isatin-3-thiosemicarbazones.

    PubMed

    Pervez, Humayun; Iqbal, Mohammad S; Tahir, Muhammad Younas; Nasim, Faiz-ul-Hassan; Choudhary, Muhammad Iqbal; Khan, Khalid Mohammed

    2008-12-01

    A series of 15 previously reported N(4)-substituted isatin-3-thiosemicarbazones 3a-o has been screened for cytotoxic, antibacterial, antifungal and urease inhibitory activities. Compounds 3b, 3e and 3n proved to be active in cytotoxicity assay; 3e exhibited a high degree of cytotoxic activity (LD(50) = 1.10 x 10(-5) M). Compound 3h exhibited significant antibacterial activity against B. subtilis, whereas compounds 3a, 3k and 3l displayed significant antifungal activity against one or more fungal strains i.e. T. longifusus, A. flavus and M. canis. In human urease enzyme inhibition assay, compounds 3g, 3k and 3m proved to be the most potent inhibitors, exhibiting relatively pronounced inhibition of the enzyme. These compounds, being non-toxic, could be potential candidates for orally effective therapeutic agents to treat certain clinical conditions induced by bacterial ureases like H. pylori urease. This study presents the first example of inhibition of urease by isatin-thiosemicarbazones and as such provides a solid basis for further research on such compounds to develop more potent inhibitors.

  16. Structural and optical characterization of thermally evaporated bismuth and antimony films for photovoltaic applications

    NASA Astrophysics Data System (ADS)

    Srimathy, N.; Ruban Kumar, A.

    2016-05-01

    In this present study, the thin film of bismuth and antimony is coated by thermal evaporation system equipped with the inbuilt ultra high vacuum system. XRD analysis confirmed the rhombohedral structure of Bismuth and Antimony on the prepared film. The surface roughness and physical appearance is analyzed by Atomic force microscopy. The results of Raman Spectroscopy show the wave functions and the spectrum of electrons. The preparation technique and conditions strongly influence the crystalline structure and the phase composition of bismuth and antimony thin films. The electrical and optical properties for the prepared film are analyzed. The results show a great interest and promising applications in Photovoltaic devices.

  17. Evaluation of the Anti-Schistosoma mansoni Activity of Thiosemicarbazones and Thiazoles

    PubMed Central

    de Oliveira, Sheilla Andrade; de Oliveira Filho, Gevânio Bezerra; Moreira, Diogo Rodrigo Magalhaes; Gomes, Paulo André Teixeira; da Silva, Anekécia Lauro; de Barros, Andréia Ferreira; da Silva, Aline Caroline; dos Santos, Thiago André Ramos; Pereira, Valéria Rêgo Alves; Gonçalves, Gabriel Gazzoni Araújo; Brayner, Fábio André; Alves, Luiz Carlos; Wanderley, Almir Gonçalves; Leite, Ana Cristina Lima

    2014-01-01

    Schistosomiasis is a chronic and debilitating disease caused by a trematode of the genus Schistosoma and affects over 207 million people. Chemotherapy is the only immediate recourse for minimizing the prevalence of this disease and involves predominately the administration of a single drug, praziquantel (PZQ). Although PZQ has proven efficacy, there is a recognized need to develop new drugs as schistosomicides since studies have shown that repeated use of this drug in areas of endemicity may cause a temporary reduction in susceptibility in isolates of Schistosoma mansoni. Hydrazones, thiosemicarbazones, phthalimides, and thiazoles are thus regarded as privileged structures used for a broad spectrum of activities and are potential candidates for sources of new drug prototypes. The present study determined the in vitro schistosomicidal activity of 10 molecules containing these structures. During the assays, parameters such motility and mortality, oviposition, morphological changes in the tegument, cytotoxicity, and immunomodulatory activity caused by these compounds were evaluated. The results showed that compounds formed of thiazole and phthalimide led to higher mortality of worms, with a significant decline in motility, inhibition of pairing and oviposition, and a mortality rate of 100% starting from 144 h of exposure. These compounds also stimulated the production of nitric oxide and tumor necrosis factor alpha (TNF-α), thereby demonstrating the presence of immunomodulatory activity. The phthalyl thiazole LpQM-45 caused significant ultrastructural alterations, with destruction of the tegument in both male and female worms. According to the present study, phthalyl thiazole compounds possess antischistosomal activities and should form the basis for future experimental and clinical trials. PMID:24165185

  18. Antibacterial, antifungal and in vitro antileukaemia activity of metal complexes with thiosemicarbazones

    PubMed Central

    Pahontu, Elena; Julea, Felicia; Rosu, Tudor; Purcarea, Victor; Chumakov, Yurie; Petrenco, Petru; Gulea, Aurelian

    2015-01-01

    1-phenyl-3-methyl-4-benzoyl-5-pyrazolone 4-ethyl-thiosemicarbazone (HL) and its copper(II), vanadium(V) and nickel(II) complexes: [Cu(L)(Cl)]·C2H5OH·(1), [Cu(L)2]·H2O (2), [Cu(L)(Br)]·H2O·CH3OH (3), [Cu(L)(NO3)]·2C2H5OH (4), [VO2(L)]·2H2O (5), [Ni(L)2]·H2O (6), were synthesized and characterized. The ligand has been characterized by elemental analyses, IR, 1H NMR and 13C NMR spectroscopy. The tridentate nature of the ligand is evident from the IR spectra. The copper(II), vanadium(V) and nickel(II) complexes have been characterized by different physico-chemical techniques such as molar conductivity, magnetic susceptibility measurements and electronic, infrared and electron paramagnetic resonance spectral studies. The structures of the ligand and its copper(II) (2, 4), and vanadium(V) (5) complexes have been determined by single-crystal X-ray diffraction. The composition of the coordination polyhedron of the central atom in 2, 4 and 5 is different. The tetrahedral coordination geometry of Cu was found in complex 2 while in complex 4, it is square planar, in complex 5 the coordination polyhedron of the central ion is distorted square pyramid. The in vitro antibacterial activity of the complexes against Escherichia coli, Salmonella abony, Staphylococcus aureus, Bacillus cereus and the antifungal activity against Candida albicans strains was higher for the metal complexes than for free ligand. The effect of the free ligand and its metal complexes on the proliferation of HL-60 cells was tested. PMID:25708540

  19. Anthropogenic impacts on the biogeochemistry and cycling of antimony.

    PubMed

    Shotyk, William; Krachler, Michael; Chen, Bin

    2005-01-01

    Antimony is a potentially toxic trace element with no known biological function. Antimony is commonly enriched in coals, and fossil fuel combustion appears to be the largest single source of anthropogenic Sb to the global atmosphere. Abundant in sulfide minerals, its emission to the atmosphere from anthropogenic activities is linked to the mining and metallurgy of non-ferrous metals, especially Pb, Cu, and Zn. In particular, the geochemical and mineralogical association of Sb with Pb minerals implies that, like Pb, Sb has been emitted to the environment for thousands of years because of Pb mining, smelting, and refining. In the US alone, there are more than 400 former secondary lead smelting operations and worldwide there are 133 Pb-Zn smelters in operation today. Antimony is used in creating and improving dozens of industrial and commercial materials including various alloys, ceramics, glasses, plastics, and synthetic fabrics, making waste incineration another important source of Sb to the environment. Enrichments of Sb in atmospheric aerosols, plants, soils, sediments, as well as alpine and polar snow and ice suggest that Sb contamination is extensive, but there are very few quantitative studies of the geographic extent, intensity, and chronology of this contamination. There is an urgent need to quantify the extent of human impacts and how these have changed with time. The decreasing inventories of anthropogenic Sb with time in peat cores from Switzerland and Scotland suggest that the atmospheric Sb flux may be declining, but there have been too few studies to make any general conclusions. In fact, some studies of sediments and biomonitors in central Europe show little decline in Sb concentrations during the past decades. There is an obvious need for reliable data from well dated archives such as polar snow and ice, peat bogs, and sediments. The air concentrations, extent of enrichment, particle size distribution, and rate of deposition of Sb in urban areas is

  20. Biogeochemistry of Antimony(V) in Microcosms under Sulfidogenic Conditions

    NASA Astrophysics Data System (ADS)

    O'Loughlin, E. J.; Johnson, C. R.; Antonopoulos, D. A.; Boyanov, M.; Flynn, T. M.; Koval, J. C.; Kemner, K. M.

    2015-12-01

    As the mining and use of antimony continues to increase, environmental concerns involving the element have grown. Antimony(V) and (III) are the two most environmentally-relevant oxidation states, but little is known about the redox transitions between the two in natural systems. To better understand the behavior of antimony in anoxic environments, we examined the transformations of Sb(V) under Fe(III)- and sulfate-reducing conditions in aqueous suspensions that contained 2 mM KSb(OH)6, 50 mM Fe(III) (as ferrihydrite), 10 mM sulfate, and 10 mM lactate, and were inoculated with sediment from a wetland on the campus of Argonne National Laboratory in Argonne, Illinois. Samples were collected over time to track changes in the concentrations of Sb, Fe(II), sulfate, and lactate, as well as the composition of the microbial community as determined by 16S rRNA gene inventories. We also examined the interaction of Sb(V) with pure Fe(II) mineral phases in aqueous suspensions containing 2 mM KSb(OH)6 and 50 mM Fe(II) as either magnetite, sideritre, vivianite, green rust, or mackinawite. X-ray absorption fine-structure spectroscopy was used to determine the valence state of Sb and its chemical speciation. Lactate was rapidly fermented to acetate and propionate concomittant with a bloom of Veillonellaceae. Utilization of propionate for dissimilatory sulfate reduction (DSR) was accompanied by an increase in Desulfobulbaceae. Sb K-edge X-Ray absorption near edge structure (XANES) analysis showed reduction of Sb(V) to Sb(III) within 4 weeks, concurrent with DSR and the formation of FeS. We observed variable responses in the ability of specific Fe(II) minerals to reduce Sb(V). No reduction was observed with magnetite, siderite, vivianite, or green rust. In the presence of mackinawite (FeS), however, Sb(V) was reduced to Sb(III) sulfide. These results suggest that the reduction of Sb(V) to Sb(III) is not likely under solely Fe(III)-reducing conditions, but is expected in sulfidogenic

  1. Precursors to Lymphoproliferative Malignancies

    PubMed Central

    Goldin, Lynn R.; McMaster, Mary L.; Caporaso, Neil E.

    2013-01-01

    We review monoclonal B-cell lymphocytosis (MBL) as a precursor to chronic lymphocytic leukemia and monoclonal gammopathy of undetermined significance (MGUS) as a precursor to plasma cell disorders. These conditions are present in the general population and increase with age. These precursors aggregate with lymphoproliferative malignancies in families suggesting shared inheritance. MBL and MGUS may share some of the same risk factors as their related malignancies but data are limited. While these conditions are characterized by enhanced risk for the associated malignancy, the majority of individuals with these conditions do not progress to malignancy. A key focus for current work is to identify markers that predict progression to malignancy. PMID:23549397

  2. Synthesis and characterisation of nano-pore antimony imprinted polymer and its use in the extraction and determination of antimony in water and fruit juice samples.

    PubMed

    Shakerian, Farid; Dadfarnia, Shayessteh; Haji Shabani, Ali Mohammad; Nili Ahmad Abadi, Maryam

    2014-02-15

    A solid phase extraction method using antimony ion imprinted polymer (IIP) sorbent combined with electrothermal atomic absorption spectrometry (ETAAS) was developed for the extraction and speciation of antimony. The sorbent has been synthesised in the presence of Sb(III) and ammonium pyrrolidine dithiocarbamate (APDC) using styrene as the monomer and ethylene glycol dimethacrylate (EGDMA) as the cross linker. The imprinted Sb(III) ions were removed by leaching with HCl (50%v/v) and the polymer was characterised by FT-IR and scanning electron microscopy. The maximum sorption capacity of the IIP for Sb(III) ions was found to be 6.7 mg g(-1). With preconcentration of 60 mL of sample, an enhancement factor of 232 and detection limit of 3.9 ng L(-1) was obtained. Total antimony was determined after the reduction of Sb(V) to Sb(III). The method was successfully applied to the determination of antimony species in water samples and total antimony in fruit juices.

  3. Silicon quantum dots with counted antimony donor implants

    NASA Astrophysics Data System (ADS)

    Singh, Meenakshi; Pacheco, Jose; Perry, Daniel; Wendt, Joel; Manginell, Ronald; Dominguez, Jason; Pluym, Tammy; Luhman, Dwight; Bielejec, Edward; Lilly, Michael; Carroll, Malcolm

    Antimony donor implants next to silicon quantum dots have been detected with integrated solid-state diode detectors with single ion precision. Devices with counted number of donors have been fabricated and low temperature transport measurements have been performed. Charge offsets, indicative of donor ionization and coupling to the quantum dot, have been detected in these devices. The number of offsets corresponds to 10-50% of the number of donors counted. We will report on tunneling time measurements and spin readout measurements on the donor offsets. This work was performed, in part, at the Center for Integrated Nanotechnologies, a U.S. DOE Office of Basic Energy Sciences user facility. The work was supported by Sandia National Laboratories Directed Research and Development Program. Sandia National Laboratories is a multi-program laboratory operated by Sandia Corporation, a Lockheed-Martin Company, for the U. S. Department of Energy under Contract No. DE-AC04-94AL85000.

  4. Copper, lead, zinc, antimony, and arsenic in Pakistan

    USGS Publications Warehouse

    White, Max Gregg

    1975-01-01

    Copper localities that merit geological investigation are found in the western Chasai District, in North Waziristan Agency, and in the Salt Range in Mianwali and Sargodha Districts. No high-grade deposits have been .reported from these ,areas and if deposits are developed they will likely be low-grade, high-tonnage, disseminated deposits. Those localities reported from Chitral State are too remote and inaccessible to be of interest now. All lead localities found to date are of minor importance; there has been small production at one .locality in Chasai District and in the southern part of the Hazara District. Zinc, antimony, and arsenic are sparse in Pakistan and no important localities of these metals are reported.

  5. Coherent and incoherent structural dynamics in laser-excited antimony

    NASA Astrophysics Data System (ADS)

    Waldecker, Lutz; Vasileiadis, Thomas; Bertoni, Roman; Ernstorfer, Ralph; Zier, Tobias; Valencia, Felipe H.; Garcia, Martin E.; Zijlstra, Eeuwe S.

    2017-02-01

    We investigate the excitation of phonons in photoexcited antimony and demonstrate that the entire electron-lattice interactions, in particular coherent and incoherent electron-phonon coupling, can be probed simultaneously. Using femtosecond electron diffraction (FED) with high temporal resolution, we observe the coherent excitation of the fully symmetric A1 g optical phonon mode via the shift of the minimum of the atomic potential energy surface. Ab initio molecular dynamics simulations on laser excited potential energy surfaces are performed to quantify the change in lattice potential and the associated real-space amplitude of the coherent atomic oscillations. Good agreement is obtained between the parameter-free calculations and the experiment. In addition, our experimental configuration allows observing the energy transfer from electrons to phonons via incoherent electron-lattice scattering events. The electron-phonon coupling is determined as a function of electronic temperature from our DFT calculations and the data by applying different models for the energy transfer.

  6. Metabolism of tellurium, antimony and germanium simultaneously administered to rats.

    PubMed

    Kobayashi, Akihiro; Ogra, Yasumitsu

    2009-06-01

    Recently, tellurium (Te), antimony (Sb) and germanium (Ge) have been used as an alloy in phase-change optical magnetic disks, such as digital versatile disk-random access memory (DVD-RAM) and DVD-recordable disk (DVD-RW). Although these metalloids, the so-called "exotic" elements, are known to be non-essential and harmful, little is known about their toxic effects and metabolism. Metalloid compounds, tellurite, antimonite and germanium dioxide, were simultaneously administered to rats. Their distributions metabolites were determined and identified by speciation. Te and Sb accumulated in red blood cells (RBCs): Te accumulated in RBCs in the dimethylated form, while Sb accumulated in the inorganic/non-methylated form. In addition, trimethyltelluronium (TMTe) was the urinary metabolite of Te, whereas Sb in urine was not methylated but oxidized. Ge was also not methylated in rats. These results suggest that each metalloid is metabolized via a unique pathway.

  7. Atomistic mechanisms governing structural stability change of zinc antimony thermoelectrics

    SciTech Connect

    Yang, Xiaolong; Lin, Jianping; Qiao, Guanjun; Wang, Zhao

    2015-01-05

    The structural stability of thermoelectric materials is a subject of growing importance for their energy harvesting applications. Here, we study the microscopic mechanisms governing the structural stability change of zinc antimony at its working temperature, using molecular dynamics combined with experimental measurements of the electrical and thermal conductivity. Our results show that the temperature-dependence of the thermal and electrical transport coefficients is strongly correlated with a structural transition. This is found to be associated with a relaxation process, in which a group of Zn atoms migrates between interstitial sites. This atom migration gradually leads to a stabilizing structural transition of the entire crystal framework, and then results in a more stable crystal structure of β–Zn{sub 4}Sb{sub 3} at high temperature.

  8. Geochemistries of arsenic, antimony, mercury, and related elements in sediments of puget sound

    USGS Publications Warehouse

    Crecelius, E.A.; Bothner, Michael H.; Carpenter, R.

    1975-01-01

    The natural distributions of arsenic, antimony mercury, chromium, cobalt, iron, aluminum, and carbon in the surface sediments of Puget Sound are perturbed by two major anthropogenic sources of trace metals: a copper smelter near Tacoma, Wash., that discharges large amounts of arsenic and antimony, and a chlor-alkali plant in Bellingham, Wash., which, in the recent past, discharged significant amounts of mercury. Arsenic and antimony inputs from the smelter over the past 80 years are evident in sediment cores whose accumulation rates have been determined by the lead-210 technique. An arsenic budget for Puget Sound reveals the importance of atmospheric input resulting from smokestack emissions of the smelter. Chemical extraction studies of sediments showed that more than 82% of the mercury was associated with easily oxidizable organic matter, whereas about 50% of both arsenic and antimony was associated with extractable iron and aluminum compounds.

  9. Concentrations of arsenic, antimony, and boron in steam and steam condensate at The Geysers, California

    USGS Publications Warehouse

    Smith, C.L.; Ficklin, W.H.; Thompson, J.M.

    1987-01-01

    Studies at The Geysers Geothermal Field, California indicate that under some circumstances elements that are transported in the vapor phase can become enriched in the liquid phase. Waters from two condensate traps (steam traps) on steam lines at The Geysers are enriched with arsenic, antimony, and boron compared to the concentrations of these elements in coexisting steam. Concentrations of boron in condensate-trap waters were as high as 160 mg/L, arsenic as high as 35 mg/L, and antimony as high as 200 ??g/L. Enrichment of arsenic, antimony, and boron is at least partially controlled by the partitioning of these elements into the liquid phase, according to their vapor-liquid distribution coefficients, after they are transported in steam. Several of the elements that are most soluble in steam, including arsenic and antimony, are part of the trace-element suite that characterizes precious-metal epithermal ore deposits. ?? 1987.

  10. Antimony Trioxide (ATO) - Summary of External Peer Review and Public Comments and Disposition

    EPA Pesticide Factsheets

    This document summarizes the public and external peer review comments that the EPA’s Office of Pollution Prevention and Toxics (OPPT) received for the draft work plan risk assessment for Antimony Trioxide (ATO).

  11. Earthquakes: hydrogeochemical precursors

    USGS Publications Warehouse

    Ingebritsen, Steven E.; Manga, Michael

    2014-01-01

    Earthquake prediction is a long-sought goal. Changes in groundwater chemistry before earthquakes in Iceland highlight a potential hydrogeochemical precursor, but such signals must be evaluated in the context of long-term, multiparametric data sets.

  12. Survey of antimony workers: mortality 1961-1992.

    PubMed Central

    Jones, R D

    1994-01-01

    The mortality of a census population and a prospective cohort of men employed on an antimony smelter in the north east of England was followed up from 1961-1992. The workers studied were exposed to a variety of agents including antimony and its oxides, arsenic and arsenic oxides, sulphur dioxide, and polycyclic aromatic hydrocarbons. The regional mortality rates were used to calculate expected deaths and a group of zircon sand workers employed on the site were used as a comparison group. For the census population of men working on the smelter before 1961 a significant increase in deaths from lung cancer was found (32 observed v 14.7 expected, P < 0.001). A similar excess was seen among maintenance men (12 observed v 5.3 expected P = 0.016). No such excess was found in the cohort recruited after 1960 (5 observed v 9.2 expected, maintenance workers 3 observed v 2.8 expected). There was evidence of a minimum latency period of around 20 years between first exposure and death from lung cancer. No evidence was found for a correlation between length of time worked and mortality from lung cancer. The results show that an increased risk of lung cancer existed in the workers employed before 1961, but it was not possible to attribute this excess to any particular agent. Mortality analysed by five year calendar periods of first exposure show a lessening of effect after 1955. Although the power of the study is clearly less for more recent periods of exposure the absence of any excess in the population after 1960 is encouraging. PMID:7849856

  13. Can microorganisms convert antimony trioxide or potassium antimonyl tartrate to methylated stibines?

    PubMed

    Gates, P N; Harrop, H A; Pridham, J B; Smethurst, B

    1997-10-20

    No evidence could be found for the production, in culture, of methylated antimony compounds from water-insoluble or soluble antimony derivatives by the aerobes, Scopulariopsis brevicaulis or Bacillus sp. or by anaerobes associated with cot mattress materials. The study does not support the hypothesis that volatile organoantimony compounds are a cause of cot deaths. Anaerobic cultures from a polluted pond generated trimethylstibine from potassium antimonyl tartrate.

  14. Antimony accumulation in Achillea ageratum, Plantago lanceolata and Silene vulgaris growing in an old Sb-mining area.

    PubMed

    Baroni, F; Boscagli, A; Protano, G; Riccobono, F

    2000-08-01

    Preliminary data of a biogeochemical survey concerning antimony transfer from soil to plants in an abandoned Sb-mining area are presented. Achillea ageratum, Plantago lanceolata and Silene vulgaris can strongly accumulate antimony when its extractable fraction in the soil is high (139-793 mg/kg). A. ageratum accumulates in basal leaves (1367 mg/kg) and inflorescences (1105 mg/kg), P. lanceolata in roots (1150 mg/kg) and S. vulgaris in shoots (1164 mg/kg). In these plant species, the efficiency of antimony accumulation decreases when the antimony availability in the soil is high. In A. ageratum and S. vulgaris, the death of the epigeal target part at the end of the growing season contributes to a reduction of the antimony load in the plant. A study to test the use of these species as bioindicators of antimony availability in soil is suggested by our results.

  15. SOLID-LIQUID PHASE EQUILIBRIUM IN BINARY SYSTEMS OF TRIPHENYL ANTIMONY WITH BIPHENYL, NAPHTHALENE, AND BENZOIC ACID.

    DTIC Science & Technology

    PHASE STUDIES, *ORGANOMETALLIC COMPOUNDS, SEMICONDUCTORS, SOLID STATE PHYSICS, ANTIMONY COMPOUNDS, EUTECTICS , ZONE MELTING, HALIDES, BISMUTH, ARSENIC, ELECTRONS, NAPHTHALENES , PHASE DIAGRAMS, SOLIDS.

  16. Simulation of antimony adsorption on nano-zero valent iron and kaolinite and analyzing the influencing parameters.

    PubMed

    Saeidnia, Setareh; Asadollahfardi, Gholamreza; Darban, Ahmad Khodadadi; Mohseni, Mehdi

    2016-01-01

    Antimony is one of the most toxic pollutants in industrial and mineral wastewaters threatening the life of humans and other creatures. We simulated the adsorption of antimony in the presence of nano-zero valent iron (nZVI) adsorbent, on kaolinite and in the presence of nZVI coated on kaolinite from mineral wastewater using VISUAL MINTEQ 3.1 software. Our aim was to determine the factors affecting the adsorption of antimony by applying simulation. The simulation was performed using an adsorption model of a diffuse layer model. The results of the simulation indicated that the nZVI concentration, initial concentrations of antimony and pH factor are effective on the adsorption of antimony. In the conducted stimulation, the optimum pH was 2-5 and the highest adsorption occurred in an acidic state. With increasing initial concentrations of antimony in the simulation, we concluded that nZVI had absorbed various concentrations above 90% and, by increasing the concentration of nZVI, antimony adsorption rate increased. The increased surface area of nZVI and the expansion of more interchangeable surfaces available for reaction with antimony ions causes more antimony ions to be adsorbed. In all cases, the coefficient of determination between the laboratory results and the model predictions that was obtained was more than 0.9.

  17. Spectroscopic evaluation of Co(II), Ni(II) and Cu(II) complexes derived from thiosemicarbazone and semicarbazone.

    PubMed

    Chandra, Sulekh; Kumar, Anil

    2007-12-31

    Co(II), Ni(II) and Cu(II) complexes were synthesized with thiosemicarbazone (L(1)) and semicarbazone (L(2)) derived from 2-acetyl furan. These complexes were characterized by elemental analysis, molar conductance, magnetic moment, mass, IR, electronic and EPR spectral studies. The molar conductance measurement of the complexes in DMSO corresponds to non-electrolytic nature. All the complexes are of high-spin type. On the basis of different spectral studies six coordinated geometry may be assigned for all the complexes except Co(L)(2)(SO(4)) and Cu(L)(2)(SO(4)) [where L=L(1) and L(2)] which are of five coordinated square pyramidal geometry.

  18. Synthesis, stereochemical, structural and biological studies of some 2,6-diarylpiperidin-4-one N(4‧)-cyclohexyl thiosemicarbazones

    NASA Astrophysics Data System (ADS)

    Sethukumar, A.; Udhaya Kumar, C.; Agilandeshwari, R.; Arul Prakasam, B.

    2013-09-01

    A new series of 2,6-diarylpiperidin-4-one N(4')-cyclohexyl thiosemicarbazones (13-23) were synthesized by corresponding 2,6-diarylpiperidin-4-ones (1-11) reaction with cyclohexyl thiosemicarbazide (12). The chemical structures were confirmed by means of IR, one and two dimensional NMR, Mass spectra and single crystal X-ray diffraction analysis. Compounds 13-23, exist in chair conformation with equatorial orientation of all the substituents at piperidine ring except the methyl group at C-5 of compounds 21-23 oriented at axial disposition to stabilize the chair conformation. Single crystal X-ray structural analysis of compound 18, evidences that the configuration about Cdbnd N double bond is syn to C-5 carbon (E-form). All the synthesized compounds were screened their biological activity.

  19. Microwave gallium-68 radiochemistry for kinetically stable bis(thiosemicarbazone) complexes: structural investigations and cellular uptake under hypoxia.

    PubMed

    Alam, Israt S; Arrowsmith, Rory L; Cortezon-Tamarit, Fernando; Twyman, Frazer; Kociok-Köhn, Gabriele; Botchway, Stanley W; Dilworth, Jonathan R; Carroll, Laurence; Aboagye, Eric O; Pascu, Sofia I

    2016-01-07

    We report the microwave synthesis of several bis(thiosemicarbazones) and the rapid gallium-68 incorporation to give the corresponding metal complexes. These proved kinetically stable under 'cold' and 'hot' biological assays and were investigated using laser scanning confocal microscopy, flow cytometry and radioactive cell retention studies under normoxia and hypoxia. (68)Ga complex retention was found to be 34% higher in hypoxic cells than in normoxic cells over 30 min, further increasing to 53% at 120 min. Our data suggests that this class of gallium complexes show hypoxia selectivity suitable for imaging in living cells and in vivo tests by microPET in nude athymic mice showed that they are excreted within 1 h of their administration.

  20. Eco-Friendly Synthesis of Some Thiosemicarbazones and Their Applications as Intermediates for 5-Arylazothiazole Disperse Dyes.

    PubMed

    Gaffer, Hatem E; Khalifa, Mohamed E

    2015-12-09

    The solid-solid reactions of thiosemicarbazide with 4-formylantipyrine, 2-acetylpyrrole and camphor were performed to afford the thiosemicarbazones 1-3 which underwent hetero-cyclization with phenacyl bromide to furnish the corresponding thiazole derivatives 4-6. The yields of the reactions are quantitative in all cases and the products do not require further purification. A series of 5-arylazo-2-(substituted ylidene-hydrazinyl)-thiazole dyes 7-9 was then prepared by diazo coupling of thiazole derivatives 4-6 with several diazonium chlorides. The synthesized dyes were applied as disperse dyes for dyeing polyester fabric. The dyed fabrics exhibit good washing, perspiration, sublimation and light fastness properties, with little variation in their moderate to good rubbing fastness.

  1. Synthesis, antioxidant activities of the nickel(II), iron(III) and oxovanadium(IV) complexes with N2O2 chelating thiosemicarbazones.

    PubMed

    Bal-Demirci, Tülay; Sahin, Musa; Ozyürek, Mustafa; Kondakçı, Esin; Ulküseven, Bahri

    2014-05-21

    The nickel(II), iron(III) and oxovanadium(IV) complexes of the N2O2 chelating thiosemicarbazones were synthesized using 4-hydroxysalicyladehyde-S-methylthiosemicarbazone and R1-substitute-salicylaldehyde (R1: 4-OH, H) in the presence of Ni(II), Fe(III), VO(IV) ions by the template reaction. The structures of the thiosemicarbazone complexes were characterized by FT-IR, (1)H NMR, elemental, ESI-MS and APCI-MS analysis. The synthesized compounds were screened for their antioxidant capacity by using the cupric reducing antioxidant capacity (CUPRAC) method. Trolox equivalent antioxidant capacity (TEAC) of iron(III) complex, 1c, was measured to be higher than that of the other complexes. Other parameters of antioxidant activity (scavenging effects on •OH, O2(•-) and H2O2) of these compounds were also determined. All the compounds have shown encouraging ROS scavenging activities.

  2. Inhibition of Bovine Viral Diarrhea Virus RNA Synthesis by Thiosemicarbazone Derived from 5,6-Dimethoxy-1-Indanone▿

    PubMed Central

    Castro, Eliana F.; Fabian, Lucas E.; Caputto, María E.; Gagey, Dolores; Finkielsztein, Liliana M.; Moltrasio, Graciela Y.; Moglioni, Albertina G.; Campos, Rodolfo H.; Cavallaro, Lucía V.

    2011-01-01

    In the present work, we described the activity of the thiosemicarbazone derived from 5,6-dimethoxy-1-indanone (TSC), which we previously characterized as a new compound that inhibits bovine viral diarrhea virus (BVDV) infection. We showed that TSC acts at a point of time that coincides with the onset of viral RNA synthesis and that it inhibits the activity of BVDV replication complexes (RCs). Moreover, we have selected five BVDV mutants that turned out to be highly resistant to TSC but still susceptible to ribavirin (RBV). Four of these resistant mutants carried an N264D mutation in the viral RNA-dependent RNA polymerase (RdRp). The remaining mutant showed an A392E mutation within the same protein. Some of these mutants replicated slower than the wild-type (wt) virus in the absence of TSC, whereas others showed a partial reversion to the wt phenotype over several passages in the absence of the compound. The docking of TSC in the crystal structure of the BVDV RdRp revealed a close contact between the indane ring of the compound and several residues within the fingers domain of the enzyme, some hydrophobic contacts, and hydrogen bonds with the thiosemicarbazone group. Finally, in the mutated RdRp from resistant BVDV, these interactions with TSC could not be achieved. Interestingly, TSC inhibited BVDV replication in cell culture synergistically with RBV. In conclusion, TSC emerges as a new nonnucleoside inhibitor of BVDV RdRp that is synergistic with RBV, a feature that turns it into a potential compound to be evaluated against hepatitis C virus (HCV). PMID:21430053

  3. Highly potent anti-proliferative effects of a gallium(III) complex with 7-chloroquinoline thiosemicarbazone as a ligand: synthesis, cytotoxic and antimalarial evaluation.

    PubMed

    Kumar, Kewal; Schniper, Sarah; González-Sarrías, Antonio; Holder, Alvin A; Sanders, Natalie; Sullivan, David; Jarrett, William L; Davis, Krystyn; Bai, Fengwei; Seeram, Navindra P; Kumar, Vipan

    2014-10-30

    A gallium(III) complex with 7-chloroquinoline thiosemicarbazone was synthesized and characterized. The complex proved to be thirty-one times more potent on colon cancer cell line, HCT-116, with considerably less cytotoxicity on non-cancerous colon fibroblast, CCD-18Co, when compared to etoposide. Its anti-malarial potential on 3D7 isolate of Plasmodium falciparum was better than lumefantrine.

  4. New Antimony Lanthanide Disulfide Dibromides LnSbS

    SciTech Connect

    Gout, D.; Jobic, S.; Evain, M.; Brec, R.

    2001-05-01

    CeSbS{sub 2}Br{sub 2} (I), Ce{sub 1/2}La{sub 1/2}SbS{sub 2}Br{sub 2} (II), and LaSbS{sub 2}Br{sub 2} (III) have been synthesized at 700 C from a mixture of LnBr{sub 3}, Ln{sub 2}S{sub 3}, Sb, and S and characterized by single-crystal X-ray diffraction. The three phases are isostructural (space group P2{sub 1}/c, Z=4) and crystallize in a novel, dense, bidimensional structure with cell parameters a=8.709(3) {angstrom}, b=9.187(2) {angstrom}, c=17.397(5) {angstrom} {beta}=104.26(3) for I, a=8.739(7) {angstrom}, b=9.219(7) {angstrom}, c=17.41(2) {angstrom}, =104.3(1) for II, and a=8.785(1) {angstrom}, b=9.236(2) {angstrom}, c=17.372(3) {angstrom}, {beta}=104.09(2) for III. In these compounds, [Ln S{sub 5}Br{sub 4}] and [Ln S{sub 3}Br{sub 6}] (Ln=Ce, La) distorted tricapped trigonal prisms define infinite {sub {infinity}}{sup 2}[LnS{sub 2}Br{sub 2}] layers counterbalanced and capped by antimony cations. In good accordance with the structural features, the charge balance in these materials is to be written Ln{sup III}Sb{sup III}S{sup -II}{sub 2}Br{sup -I}{sub 2}. These compounds exhibit a yellow hue with a measured absorption threshold of 2.42(1), 2.55(1), and 2.72(1) eV for I, II, and III, respectively. In the two cerium containing bromothioantimonates I and II, the origin of the color is assigned to a Ce-4f{yields}Ce-5d electronic transition, which shifts to higher energy from I to II due either to a matrix effect (increase of the mean Ln-S distances under the substitution of Ce for La) or to an atomic ordering between Ce and La cations on the Ln(1) and Ln(2) crystallographic sites. In contrast, the electronic transition at play in III involves a charge transfer from the bromine and sulfur ions to the antimony ions, the latter contributing substantially to the lowermost levels of the conduction band.

  5. Synthesis and characterization of mixed-ligand diimine-piperonal thiosemicarbazone complexes of ruthenium(II): Biophysical investigations and biological evaluation as anticancer and antibacterial agents

    NASA Astrophysics Data System (ADS)

    Beckford, Floyd A.; Thessing, Jeffrey; Shaloski, Michael, Jr.; Canisius Mbarushimana, P.; Brock, Alyssa; Didion, Jacob; Woods, Jason; Gonzalez-Sarrías, Antonio; Seeram, Navindra P.

    2011-04-01

    We have used a novel microwave-assisted method developed in our laboratories to synthesize a series of ruthenium-thiosemicarbazone complexes. The new thiosemicarbazone ligands are derived from benzo[ d][1,3]dioxole-5-carbaldehyde (piperonal) and the complexes are formulated as [(diimine) 2Ru(TSC)](PF 6) 2 (where the TSC is the bidentate thiosemicarbazone ligand). The diimine in the complexes is either 2,2'-bipyridine or 1,10-phenanthroline. The complexes have been characterized by spectroscopic means (NMR, IR and UV-Vis) as well as by elemental analysis. We have studied the biophysical characteristics of the complexes by investigating their anti-oxidant ability as well as their ability to disrupt the function of the human topoisomerase II enzyme. The complexes are moderately strong binders of DNA with binding constants of 10 4 M -1. They are also strong binders of human serum albumin having binding constants on the order of 10 4 M -1. The complexes show good in vitro anticancer activity against human colon cancer cells, Caco-2 and HCT-116 and indeed show some cytotoxic selectivity for cancer cells. The IC 50 values range from 7 to 159 μM (after 72 h drug incubation). They also have antibacterial activity against Gram-positive strains of pathogenic bacteria with IC 50 values as low as 10 μM; little activity was seen against Gram-negative strains. It has been established that all the compounds are catalytic inhibitors of human topoisomerase II.

  6. Copper(II) complexes with highly water-soluble L- and D-proline-thiosemicarbazone conjugates as potential inhibitors of Topoisomerase IIα.

    PubMed

    Bacher, Felix; Enyedy, Éva A; Nagy, Nóra V; Rockenbauer, Antal; Bognár, Gabriella M; Trondl, Robert; Novak, Maria S; Klapproth, Erik; Kiss, Tamás; Arion, Vladimir B

    2013-08-05

    Two proline-thiosemicarbazone bioconjugates with excellent aqueous solubility, namely, 3-methyl-(S)-pyrrolidine-2-carboxylate-2-formylpyridine thiosemicarbazone [L-Pro-FTSC or (S)-H2L] and 3-methyl-(R)-pyrrolidine-2-carboxylate-2-formylpyridine thiosemicarbazone [D-Pro-FTSC or (R)-H2L], have been synthesized and characterized by elemental analysis, one- and two-dimensional (1)H and (13)C NMR spectroscopy, and electrospray ionization mass spectrometry. The complexation behavior of L-Pro-FTSC with copper(II) in an aqueous solution and in a 30% (w/w) dimethyl sulfoxide/water mixture has been studied via pH potentiometry, UV-vis spectrophotometry, electron paramagnetic resonance, (1)H NMR spectroscopy, and spectrofluorimetry. By the reaction of copper(II) acetate with (S)-H2L and (R)-H2L in water, the complexes [Cu(S,R)-L] and [Cu(R,S)-L] have been synthesized and comprehensively characterized. An X-ray diffraction study of [Cu(S,R)-L] showed the formation of a square-pyramidal complex, with the bioconjugate acting as a pentadentate ligand. Both copper(II) complexes displayed antiproliferative activity in CH1 ovarian carcinoma cells and inhibited Topoisomerase IIα activity in a DNA plasmid relaxation assay.

  7. Synthesis of a Sugar-Based Thiosemicarbazone Series and Structure-Activity Relationship versus the Parasite Cysteine Proteases Rhodesain, Cruzain, and Schistosoma mansoni Cathepsin B1

    PubMed Central

    Fonseca, Nayara Cristina; da Cruz, Luana Faria; da Silva Villela, Filipe; do Nascimento Pereira, Glaécia Aparecida; de Siqueira-Neto, Jair Lage; Kellar, Danielle; Suzuki, Brian M.; Ray, Debalina; de Souza, Thiago Belarmino; Alves, Ricardo José; Júnior, Policarpo Ademar Sales; Romanha, Alvaro José; Murta, Silvane Maria Fonseca; McKerrow, James H.; Caffrey, Conor R.; de Oliveira, Renata Barbosa

    2015-01-01

    The pressing need for better drugs against Chagas disease, African sleeping sickness, and schistosomiasis motivates the search for inhibitors of cruzain, rhodesain, and Schistosoma mansoni CB1 (SmCB1), the major cysteine proteases from Trypanosoma cruzi, Trypanosoma brucei, and S. mansoni, respectively. Thiosemicarbazones and heterocyclic analogues have been shown to be both antitrypanocidal and inhibitory against parasite cysteine proteases. A series of compounds was synthesized and evaluated against cruzain, rhodesain, and SmCB1 through biochemical assays to determine their potency and structure-activity relationships (SAR). This approach led to the discovery of 6 rhodesain, 4 cruzain, and 5 SmCB1 inhibitors with 50% inhibitory concentrations (IC50s) of ≤10 μM. Among the compounds tested, the thiosemicarbazone derivative of peracetylated galactoside (compound 4i) was discovered to be a potent rhodesain inhibitor (IC50 = 1.2 ± 1.0 μM). The impact of a range of modifications was determined; removal of thiosemicarbazone or its replacement by semicarbazone resulted in virtually inactive compounds, and modifications in the sugar also diminished potency. Compounds were also evaluated in vitro against the parasites T. cruzi, T. brucei, and S. mansoni, revealing active compounds among this series. PMID:25712353

  8. Light-Induced Bistability in Iron(III) Spin-Transition Compounds of 5 X-Salicylaldehyde Thiosemicarbazone (X=H, Cl, Br).

    PubMed

    Yemeli, Eddy W T; Blake, Graeme R; Douvalis, Alexios P; Bakas, Thomas; Alberda van Ekenstein, Gert O R; van Koningsbruggen, Petra J

    2010-10-19

    The iron(III) spin-crossover compounds [Fe(Hthsa)(thsa)]⋅H2 O (1), [Fe(Hth5Clsa)(th5Clsa)2 ]⋅H2 O (2), and [Fe(Hth5Brsa)(th5Brsa)2 ]⋅H2 O (3) (H2 thsa=salicylaldehyde thiosemicarbazone, H2 th5Clsa=5-chlorosalicylaldehyde thiosemicarbazone, and H2 th5Brsa=5-bromosalicylaldehyde thiosemicarbazone) have been synthesized and their spin-transition properties investigated by magnetic susceptibility, Mössbauer spectroscopy, and differential scanning calorimetry measurements. The three compounds exhibit an abrupt spin transition with a thermal hysteresis effect. The more polarizable the substituent on the salicylaldehyde moiety, the more complete is the transition at room temperature with an increased degree of cooperativity. The molecular structures of 1 and 2 in the high-spin state are revealed. The occurrence of the light-induced excited-spin-state trapping phenomenon appears to be dependent on the substituent incorporated into the 5-position of the salicylaldehyde subunit. Whereas the compounds with an electron-withdrawing group (-Br or -Cl) exhibit light-induced trapped excited high-spin states with great longevity of metastability, the halogen-free compound does not, even though strong intermolecular interactions (such as hydrogen-bonding networks and π stacking) operate in the system. For compound 2, the surface level of photoconversion is less than 35 %. In contrast, compound 3 displays full photoexcitation.

  9. Levels and risk factors of antimony contamination in human hair from an electronic waste recycling area, Guiyu, China.

    PubMed

    Huang, Yue; Ni, Wenqing; Chen, Yaowen; Wang, Xiaoling; Zhang, Jingwen; Wu, Kusheng

    2015-05-01

    The primitive electronic waste (e-waste) recycling has brought a series of environmental pollutants in Guiyu, China. Antimony is one of the important metal contaminants and has aroused the global concerns recently. We aimed to investigate concentrations of antimony in human hair from Guiyu and compared them with those from a control area where no e-waste recycling exists, and assessed the potential risk factors. A total of 205 human hair samples from Guiyu and 80 samples from Jinping were collected for analysis. All volunteers were asked to complete a questionnaire including socio-demographic characteristics and other possible factors related to hair antimony exposure. The concentrations of hair antimony were analyzed using atomic absorption spectrophotometer. Our results indicated that the level of hair antimony in volunteers from Guiyu (median, 160.78; range, 6.99-4412.59 ng/g) was significantly higher than those from Jinping (median, 61.74; range, 2.98-628.43 ng/g). The residents who engaged in e-waste recycling activities in Guiyu had higher hair antimony concentrations than others (P < 0.001). There was no significant difference of hair antimony concentrations among different occupation types in e-waste recycling. Multiple stepwise regression analysis indicated that hair antimony concentrations were associated with education level (β = -0.064), the time of residence in Guiyu (β = 0.112), living house also served as e-waste workshop (β = 0.099), the work related to e-waste (β = 0.169), and smoking (β = 0.018). The elevated hair antimony concentrations implied that the residents in Guiyu might be at high risk of antimony contamination, especially the e-waste recycling workers. Work related to e-waste recycling activities and long-time residence in Guiyu contributed to the high hair antimony exposure.

  10. Determination of antimony by using tungsten trap atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Titretir, Serap; Kendüzler, Erdal; Arslan, Yasin; Kula, İbrahim; Bakırdere, Sezgin; Ataman, O. Yavuz.

    2008-08-01

    An electrically heated tungsten coil was used as a trap in the determination of antimony. The technique consists of three steps. Initially, SbH 3 is formed by hydride generation procedure; then the analyte species in vapor form are transported to W-coil trap heated at 370 °C. Following the preconcentration step, the trap is heated to 895 °C; analyte species are revolatilized and transported to the flame-heated quartz atom cell where atomization and the formation of signal take place. The experimental parameters were optimized both for trap and no-trap studies. The most important experimental parameters are concentrations of HCl and NaBH 4 solutions, H 2 and Ar gas flow rates, and collection and revolatilization temperatures of W-coil. Accuracy was tested using a certified reference material, waste water EU-L-1. Limit of detection for the system is 16 ng l - 1 using a sample of 36 ml collected in 4.0 min. Enhancement factor in sensitivity was 17.

  11. Calcium-Antimony Alloys as Electrodes for Liquid Metal Batteries

    SciTech Connect

    Ouchi, T; Kim, H; Ning, XH; Sadoway, DR

    2014-08-08

    The performance of a calcium-antimony (Ca-Sb) alloy serving as the positive electrode in a Ca vertical bar vertical bar Sb liquid metal battery was investigated in an electrochemical cell, Ca(in Bi) vertical bar LiCl-NaCl-CaCl2 vertical bar Ca(in Sb). The equilibrium potential of the Ca-Sb electrode was found to lie on the interval, 1.2-0.95 V versus Ca, in good agreement with electromotive force (emf) measurements in the literature. During both alloying and dealloying of Ca at the Sb electrode, the charge transfer and mass transport at the interface are facile enough that the electrode potential varies linearly from 0.95 to 0.75 V vs Ca(s) as current density varies from 50 to 500 mA cm(-2). The discharge capacity of the Ca vertical bar vertical bar Sb cells increases as the operating temperature increases due to the higher solubility and diffusivity of Ca in Sb. The cell was successfully cycled with high coulombic efficiency (similar to 100%) and small fade rate (<0.01% cycle(-1)). These data combined with the favorable costs of these metals and salts make the Ca vertical bar vertical bar Sb liquid metal battery attractive for grid-scale energy storage. (C) The Author(s) 2014. Published by ECS. All rights reserved.

  12. Removal of antimony from copper by injection of soda ash

    NASA Astrophysics Data System (ADS)

    Stapurewicz, Tadeusz T.; Themelis, Nickolas J.

    1990-12-01

    The removal of Sb from molten copper is of importance in the development of processes which can smelt copper concentrates directly into copper in a single furnace. A promising method is injection of oxygen and sodium carbonate in a modified anode furnace. This study encompassed a thermodynamic analysis of the impurity removal reactions and an experimental investigation of antimony removal from molten copper in a 15 kW induction furnace. The results showed that the reaction was controlled by diffusion of Sb in the metal phase. The reaction between metal and injected flux can be divided into two subprocesses-. (1) “transitory contact” reaction to the injected flux particles as they rise through the melt and (2) “permanent contact” reaction across the interface between the metal bath and the supernatant slag layer. On the basis of the experimental work, the overall volumetric mass transfer coefficient (cm3/s) at 1473 K was expressed in terms of the two subprocesses as follows: (k d A) ov = (k d A) pc + (k d A) tc = 1.25Q{g/0.29} + 0.28 (H Q f ) where Q g is the injection gas flow rate in normal liters per minute, H is the depth of injection in centimeters, and Q f the rate of flux injection in grams per second.

  13. Increased metacyclogenesis of antimony-resistant Leishmania donovani clinical lines.

    PubMed

    Ouakad, M; Vanaerschot, M; Rijal, S; Sundar, S; Speybroeck, N; Kestens, L; Boel, L; De Doncker, S; Maes, I; Decuypere, S; Dujardin, J-C

    2011-09-01

    Mathematical models predict that the future of epidemics of drug-resistant pathogens depends in part on the competitive fitness of drug-resistant strains. Considering metacyclogenesis (differentiation process essential for infectivity) as a major contributor to the fitness of Leishmania donovani, we tested its relationship with pentavalent antimony (SbV) resistance in clinical lines. Different methods for the assessment of metacyclogenesis were cross-validated: gene expression profiling (META1 and SHERP), morphometry (microscopy and FACS), in vitro infectivity to macrophages and resistance to complement lysis. This was done on a model constituted by 2 pairs of reference strains cloned from a SbV-resistant and -sensitive isolate. We selected the most adequate parameter and extended the analysis of metacyclogenesis diversity to a sample of 20 clinical lines with different in vitro susceptibility to the drug. The capacity of metacyclogenesis, as measured by the complement lysis test, was shown to be significantly higher in SbV-resistant clinical lines of L. donovani than in SbV-sensitive lines. Together with other lines of evidence, it is concluded that L. donovani constitutes a unique example and model of drug-resistant pathogens with traits of increased fitness. These findings raise a fundamental question about the potential risks of selecting more virulent pathogens through massive chemotherapeutic interventions.

  14. Mitochondrial Proteomics of Antimony and Miltefosine Resistant Leishmania infantum

    PubMed Central

    Vincent, Isabel M.; Racine, Gina; Légaré, Danielle; Ouellette, Marc

    2015-01-01

    Antimony (SbIII) and miltefosine (MIL) are important drugs for the treatment of Leishmania parasite infections. The mitochondrion is likely to play a central role in SbIII and MIL induced cell death in this parasite. Enriched mitochondrial samples from Leishmania promastigotes selected step by step for in vitro resistance to SbIII and MIL were subjected to differential proteomic analysis. A shared decrease in both mutants in the levels of pyruvate dehydrogenase, dihydrolipoamide dehydrogenase, and isocitrate dehydrogenase was observed, as well as a differential abundance in two calcium-binding proteins and the unique dynamin-1-like protein of the parasite. Both mutants presented a shared increase in the succinyl-CoA:3-ketoacid-coenzyme A transferase and the abundance of numerous hypothetical proteins was also altered in both mutants. In general, the proteomic changes observed in the MIL mutant were less pronounced than in the SbIII mutant, probably due to the early appearance of a mutation in the miltefosine transporter abrogating the need for a strong mitochondrial adaptation. This study is the first analysis of the Leishmania mitochondrial proteome and offers powerful insights into the adaptations to this organelle during SbIII and MIL drug resistance. PMID:28248274

  15. Antimony bioavailability: knowledge and research perspectives for sustainable agricultures.

    PubMed

    Pierart, Antoine; Shahid, Muhammad; Séjalon-Delmas, Nathalie; Dumat, Camille

    2015-05-30

    The increasing interest in urban agriculture highlights the crucial question of crop quality. The main objectives for environmental sustainability are a decrease in chemical inputs, a reduction in the level of pollutants, and an improvement in the soil's biological activity. Among inorganic pollutants emitted by vehicle traffic and some industrial processes in urban areas, antimony (Sb) is observed on a global scale. While this metalloid is known to be potentially toxic, it can transfer from the soil or the atmosphere to plants, and accumulate in their edible parts. Urban agriculture is developing worldwide, and could therefore increasingly expose populations to Sb. The objective of this review was in consequences to gather and interpret actual knowledge of Sb uptake and bioaccumulation by crops, to reveal investigative fields on which to focus. While there is still no legal maximal value for Sb in plants and soils, light has to be shed on its accumulation and the factors affecting it. A relative absence of data exists about the role of soil flora and fauna in the transfer, speciation and compartmentation of Sb in vegetables. Moreover, little information exists on Sb ecotoxicity for terrestrial ecosystems. A human risk assessment has finally been reviewed, with particular focus on Sb bioaccessibility.

  16. Thermal Stability of Nanocrystalline Copper Alloyed with Antimony

    NASA Astrophysics Data System (ADS)

    Atwater, Mark A.; Mula, Suhrit; Scattergood, Ronald O.; Koch, Carl C.

    2013-12-01

    Nanocrystalline copper (Cu) was generated by cryogenic, high-energy ball milling. Antimony (Sb) was added to investigate its utility in stabilizing the grain structure during annealing up to a maximum temperature of 1073 K (800 °C). When alloyed with Sb in quantities up to 1 at. pct, thermal stability was maintained up to 673 K (400 °C). Cu and Sb have very different molar volumes which can drive segregation of the solute due to the elastic strain energy and hence stabilize the grain size by reducing grain boundary energy. The elastic mismatch of Sb in Cu is calculated to be quite large (113 kJ/mol) when molar volume is used, but when an equivalent equation using atomic radius is applied, the driving force is nearly an order of magnitude lower (~12 kJ/mol). The low elastic mismatch is corroborated by the large equilibrium solubility of Sb in Cu. The results for the Cu-Sb system are compared to the nanocrystalline Ni-W system and the large amount of equilibrium solubility of the solute in both cases is thought to hinder thermal stabilization since segregation is not strongly favored.

  17. Yb3+/Ho3+-codoped antimony-silicate optical fiber

    NASA Astrophysics Data System (ADS)

    Żmojda, Jacek; Dorosz, Dominik; Kochanowicz, Marcin; Miluski, Piotr; Dorosz, Jan

    2012-05-01

    The emission properties of Yb3+/Ho3+-codoped antimony-silicate optical fiber has been investigated. Luminescence at 2.1 μm corresponding to 5I7--> 5I8 transition in holmium was obtained by energy transfer between Yb3+ and Ho3+ ions. According to the Dexter-Miyakawa model, the parameters of energy migration CDD of the 2F5/2 (Yb3+) <--> 2F5/2 (Yb3+) transition and direct energy transfer CDA of the 2F5/2 (Yb3+) --> 5I6 (Ho3+) transition was calculated. The optimization of the activator content and the concentration ratio were conducted with the purpose of maximizing the efficiency of energy transfer. It made possible to select best-suited glass which was used to manufacture double-clad optical fiber. Strong and narrow bands of spontaneous emission which formed as a result of energy transfer between ytterbium and holmium ions were observed in the fiber under exciting with radiation at 978 nm wavelength.

  18. Yb3+/Ho3+-codoped antimony-silicate optical fiber

    NASA Astrophysics Data System (ADS)

    Żmojda, Jacek; Dorosz, Dominik; Kochanowicz, Marcin; Miluski, Piotr; Dorosz, Jan

    The emission properties of Yb3+/Ho3+-codoped antimony-silicate optical fiber has been investigated. Luminescence at 2.1 μm corresponding to 5I7--> 5I8 transition in holmium was obtained by energy transfer between Yb3+ and Ho3+ ions. According to the Dexter-Miyakawa model, the parameters of energy migration CDD of the 2F5/2 (Yb3+) <--> 2F5/2 (Yb3+) transition and direct energy transfer CDA of the 2F5/2 (Yb3+) --> 5I6 (Ho3+) transition was calculated. The optimization of the activator content and the concentration ratio were conducted with the purpose of maximizing the efficiency of energy transfer. It made possible to select best-suited glass which was used to manufacture double-clad optical fiber. Strong and narrow bands of spontaneous emission which formed as a result of energy transfer between ytterbium and holmium ions were observed in the fiber under exciting with radiation at 978 nm wavelength.

  19. Electrochemical antimony removal from accumulator acid: results from removal trials in laboratory cells.

    PubMed

    Bergmann, M E Henry; Koparal, A Savas

    2011-11-30

    Regeneration of spent accumulator acid could be an alternative process for crystallization, neutralisation and disposal. Therefore, for the first time in a study of the possibilities of electrochemical removal of antimony and accumulator acid regeneration on a laboratory scale, two synthetic and several real systems containing sulfuric acid of concentrations ranging between 28% and 36%, and antimony species were tested. Discontinuous electrochemical reactors with anion exchange membranes were successfully used in these experiments, which were conducted at a temperature of 35°C. Removal of antimony using cells that were not divided by a separator, however, was not possible. In selected experiments, by varying the electrode material, type of electrolyte, and cell current, the concentration of antimony could be reduced from the range of 5 ppm to 0.15 ppm. This resulted in current efficiencies between 0.00002% and 0.001%, and in specific electroenergy demands between 100 Wh L(-1) and 2000 Wh L(-1). In other experiments on substances with antimony contents up to 3500 mg L(-1), the current efficiencies obtained were more than a thousandfold higher. In contrast to the formally high relative energy consumption parameters absolute demand parameters are relatively small and favour the electrochemical method in small scale application. Besides plate electrodes, 3D-cathodes were used. Copper- and graphite cathodes produced the best results.

  20. Two cases of visceral leishmaniasis in Colombia resistant to meglumine antimonial treatment.

    PubMed

    Vélez, Iván Darío; Colmenares, Lina María; Muñoz, Carlos Aguirre

    2009-01-01

    Visceral leishmaniasis (VL) affects over 500,000 people worldwide each year. The disease occurs in the Mediterranean basin, Central and South America and is caused by Leishmania infantum (syn L. chagasi). VL is an endemic disease in Colombia, particularly along the Caribbean coast and the Magdalena River Valley and 90% of VL cases occur in children under the age of five. The first line of treatment is chemotherapy with pentavalent antimonial compounds, including sodium stibogluconate (Pentostam) and meglumine antimoniate (Glucantime). These compounds are the ones most used in Colombia, at a dose of 20 mg/kg/day for 28 days. Nevertheless resistance of L. infantum to pentavalent antimonials is becoming an important problem. No cases of VL resistant to pentavalent antimonial compounds have previously been reported from Colombia. This report describes the two cases of VL resistance to antimonial compounds in a girl and a boy who did not respond to previous treatment with Pentacarinat and Glucantime regimens but were treated successfully with liposomal amphotericin B. Based on our findings, we recommend liposomal amphotericin B as the first line of treatment for VL due to its low toxicity, shorter administration period and the low price obtained by WHO.

  1. Copper-promoted cementation of antimony in hydrochloric acid system: A green protocol.

    PubMed

    Wu, Lian-Kui; Li, Ying-Ying; Cao, Hua-Zhen; Zheng, Guo-Qu

    2015-12-15

    A new method of recovering antimony in hydrochloric acid system by cementation with copper powder was proposed and carried out at laboratory scale. Thermodynamic analysis and cyclic voltammetry test were conducted to study the cementation process. This is a novel antimony removal technology and quite meets the requirements of green chemistry. The main cement product Cu2Sb is a promising anodic material for lithium and sodium ion battery. And nearly all consumed copper powder are transformed into CuCl which is an important industrial material. The effect of reaction temperature, stoichiometric ratio of Cu to Sb(III), stirring rate and concentration of HCl on the cementation efficiency of antimony were investigated in detail. Optimized cementation condition is obtained at 60 °C for 120 min and stirring rate of 600 rpm with Cu/Sb(III) stoichiometric ratio of 6 in 3 mol L(-1) HCl. At this time, nearly all antimony can be removed by copper powder and the cementation efficiency is over 99%. The structure and morphologies of the cement products were characterized by X-ray diffraction and scanning electron microscopy, respectively. Results show that the reaction temperature has little influence on the morphology of the cement products which consist of particles with various sizes. The activation energy of the cementation antimony on copper is 37.75 kJ mol(-1), indicating a chemically controlled step. Inductively coupled plasma mass spectrometry results show that no stibine generates during the cementation process.

  2. Antimony leaching in plastics from waste electrical and electronic equipment (WEEE) with various acids and gamma irradiation

    SciTech Connect

    Tostar, Sandra; Stenvall, Erik; Boldizar, Antal; Foreman, Mark R. St. J.

    2013-06-15

    Highlights: • We have proposed a method to recover antimony from electronic plastics. • The most efficient acid solution was sodium hydrogen tartrate in dimethyl sulfoxide. • Gamma irradiation did not influence the antimony leaching ability. - Abstract: There has been a recent interest in antimony since the availability in readily mined areas is decreasing compared to the amounts used. It is important in many applications such as flame retardants and in the production of polyester, which can trigger an investigation of the leachability of antimony from plastics using different acids. In this paper, different types of acids are tested for their ability to leach antimony from a discarded computer housing, made of poly(acrylonitrile butadiene styrene), which is a common plastic type used in electrical and electronic equipment. The acid solutions included sodium hydrogen tartrate (0.5 M) dissolved in either dimethyl sulfoxide or water (at ca. 23 °C and heated to ca. 105 °C). The metal content after leaching was determined by inductively coupled plasma optical emission spectroscopy. The most efficient leaching medium was the heated solution of sodium hydrogen tartrate in dimethyl sulfoxide, which leached almost half of the antimony from the poly(acrylonitrile butadiene styrene). Gamma irradiation, which is proposed to improve the mechanical properties in plastics, was used here to investigate the influence of antimony leaching ability. No significant change in the amount of leached antimony could be observed.

  3. First Report on Infant Acute Urticaria after Mother’s Parenteral Use of Meglumine Antimoniate (Glucantime): A Case Report

    PubMed Central

    MOZAFARI, Omid; SHOROFI, Seyed Afshin; YOUSEFI, Seyde Sedighe

    2016-01-01

    Pentavalent antimonials are still the first drug of choice for the treatment of cutaneous leishmaniasis (CL). Like other treatments, they can cause adverse reactions including musculoskeletal pain, gastrointestinal disturbances, and mild to moderate headaches. In this paper, we report the first case of an infant who developed acute urticaria after her mother’s parenteral use of meglumine antimoniate (glucantime). PMID:27957467

  4. SESPE-FRAZIER, DIABLO, MATILIJA, DRY LAKES, SAWMILL-BADLANDS, CUYAMA, ANTIMONY, AND QUATAL ROADLESS AREAS, CALIFORNIA.

    USGS Publications Warehouse

    Frizzell, Virgil A.; Hale, William N.

    1984-01-01

    The study area, consisting of the Sespe-Frazier, Diablo, Matilija, Dry Lakes, Sawmill-Badlands, Cuyama, Antimony, and Quatal Roadless Areas, occupies about 872 sq mi in the Los Padres National Forest, California. Studies indicate that the Sespe-Frazier Roadless Area contains demonstrated resources of gold, gypsum, phosphate and bentonite; deposits in the Cuyama Roadless Area have demonstrated resources of gypsum; mines in the Antimony Roadless Area have demonstrated resources of antimony, gold, silver, and marble; and the Quatal Roadless Area has demonstrated resources of bentonite. The Sespe-Frazier Roadless Area has substantiated potential for geothermal resources suitable for direct-heat purposes, probable and substantiated potential for oil and gas resources, and probable potential for gold resources. Small areas of probable resource potential for antimony and gold were identified in Antimony Roadless Area.

  5. Antimony mediated growth of high-density InAs quantum dots for photovoltaic cells

    SciTech Connect

    Tutu, F. K.; Wu, J.; Lam, P.; Tang, M.; Liu, H.; Miyashita, N.; Okada, Y.; Wilson, J.; Allison, R.

    2013-07-22

    We report enhanced solar cell performance using high-density InAs quantum dots. The high-density quantum dot was grown by antimony mediated molecular beam epitaxy. In-plane quantum dot density over 1 × 10{sup 11} cm{sup −2} was achieved by applying a few monolayers of antimony on the GaAs surface prior to quantum dot growth. The formation of defective large clusters was reduced by optimization of the growth temperature and InAs coverage. Comparing with a standard quantum dot solar cell without the incorporation of antimony, the high-density quantum dot solar cell demonstrates a distinct improvement in short-circuit current from 7.4 mA/cm{sup 2} to 8.3 mA/cm{sup 2}.

  6. Trophic transfer of arsenic and antimony in a freshwater ecosystem: a field study.

    PubMed

    Culioli, Julia-Laurence; Fouquoire, Aurélie; Calendini, Serge; Mori, Christophe; Orsini, Antoine

    2009-10-04

    The distribution of arsenic and antimony discharges related to a past mining activity in the Bravona River and its tributary, the Presa River, was investigated. We determined levels of arsenic and antimony in the water and the biota (bryophytes, benthic macroinvertebrates and fish), along a pollution gradient. Concentrations of metalloids downstream mining wastes were significantly higher than those in reference station sites. The pattern of accumulation of arsenic in the food chain decreased as follows: macroinvertebrates>bryophytes>water>fish tissues. For antimony, the lowest concentrations were found in water. The accumulation of metals in invertebrate taxa depends on their place in the food chain, their feeding behavior, and their specific habit (lenitophilic/rheophilic species). Concentrations of both metalloids decreased with increasing trophic level.

  7. Process for treating spent catalyst including antimony halides from chlorofluorocarbon production

    SciTech Connect

    Kalcevic, V.; McGahan, J.F.

    1988-06-14

    A process for treating spent catalyst from chlorofluorocarbon production is described wherein the catalyst includes antimony halides and undergoes hydrolysis in an aqueous medium to produce insoluble antimony compounds and fluoride ions. The process comprises hydrolyzing the catalyst in an aqueous solution of ferric chloride having a sufficient concentration of ferric ions to complex substantially all of the fluoride ions produced upon hydrolysis of the catalyst, neutralizing the reaction mass present following hydrolysis of the catalyst and complexing of the fluoride ions by contacting the reaction mass with an aqueous suspension of a compound selected from the class consisting of calcium hydroxide and magnesium hydroxide, and separating the insoluble antimony compounds from the neutralized reaction mass.

  8. Study of upscaling possibilities for antimony sulfide solid state sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Nikolakopoulou, Archontoula; Raptis, Dimitrios; Dracopoulos, Vasilios; Sygellou, Lamprini; Andrikopoulos, Konstantinos S.; Lianos, Panagiotis

    2015-03-01

    Solid state solar cells of inverted structure were constructed by successive deposition of nanoparticulate titania, antimony sulfide sensitizer and P3HT on FTO electrodes with PEDOT:PSS:Ag as counter electrode. Sensitized photoanode electrodes were characterized by XRD, Raman, XPS, FESEM and UV-vis. Small laboratory scale cells were first constructed and optimized. Functional cells were obtained by annealing the antimony sulfide film either in air or in inert atmosphere. High short-circuit currents were recorded in both cases with air-annealed sample producing more current but lower voltage. Small unit cells were combined to form cell modules. Connection of unit cells in parallel increased current but not proportionally to that of the unit cell. Connection in series preserved current and generated voltage multiplication. Cells were constructed and studied under ambient conditions, without encapsulation. The results encourage upscaling of antimony sulfide solar cells.

  9. Spectrophotometric procedure using rhodamine B for determination of submicrogram quantities of antimony in rocks

    USGS Publications Warehouse

    Schnepfe, M.M.

    1973-01-01

    A spectrophotometric procedure using Rhodamine B is given for the determination of antimony in mineralized rocks after its separation as stibine. A study of the Rhodamine B reaction points to the importance of the order of addition of reagents in enhancing sensitivity and increasing the stability of the system. The tolerance of some 26 elements is established for the overall procedure. Although the limit of determination is approximately 0??5 ppm Sb in a 0??2-g sample, the procedure is intended primarily for screening samples containing more than 1 ppm Sb. In pure solutions 0??1 ??g of antimony can be determined with a relative standard deviation of 25%. For >0??2 ??g of antimony a relative standard deviation of 15% or less can be expected. ?? 1973.

  10. Concentration transient analysis of antimony surface segregation during Si(100) molecular beam epitaxy

    NASA Technical Reports Server (NTRS)

    Markert, L. C.; Greene, J. E.; Ni, W.-X.; Hansson, G. V.; Sundgren, J.-E.

    1991-01-01

    Antimony surface segregation during Si(100) molecular beam epitaxy (MBE) was investigated at temperatures T(sub s) = 515 - 800 C using concentration transient analysis (CTA). The dopant surface coverage Theta, bulk fraction gamma, and incorporation probability sigma during MBE were determined from secondary-ion mass spectrometry depth profiles of modulation-doped films. Programmed T(sub s) changes during growth were used to trap the surface-segregated dopant overlayer, producing concentration spikes whose integrated area corresponds to Theta. Thermal antimony doping by coevaporation was found to result in segregation strongly dependent on T(sub s) with Theta(sub Sb) values up to 0.9 monolayers (ML): in films doped with Sb(+) ions accelerated by 100 V, Theta(sub Sb) was less than or equal to 4 x 10(exp -3) ML. Surface segregation of coevaporated antimony was kinematically limited for the film growth conditions in these experiments.

  11. Use of Antimony in the Treatment of Leishmaniasis: Current Status and Future Directions

    PubMed Central

    Haldar, Arun Kumar; Sen, Pradip; Roy, Syamal

    2011-01-01

    In the recent past the standard treatment of kala-azar involved the use of pentavalent antimonials Sb(V). Because of progressive rise in treatment failure to Sb(V) was limited its use in the treatment program in the Indian subcontinent. Until now the mechanism of action of Sb(V) is not very clear. Recent studies indicated that both parasite and hosts contribute to the antimony efflux mechanism. Interestingly, antimonials show strong immunostimulatory abilities as evident from the upregulation of transplantation antigens and enhanced T cell stimulating ability of normal antigen presenting cells when treated with Sb(V) in vitro. Recently, it has been shown that some of the peroxovanadium compounds have Sb(V)-resistance modifying ability in experimental infection with Sb(V) resistant Leishmania donovani isolates in murine model. Thus, vanadium compounds may be used in combination with Sb(V) in the treatment of Sb(V) resistance cases of kala-azar. PMID:22091408

  12. Future trends of global atmospheric antimony emissions from anthropogenic activities until 2050

    NASA Astrophysics Data System (ADS)

    Zhou, Junrui; Tian, Hezhong; Zhu, Chuanyong; Hao, Jiming; Gao, Jiajia; Wang, Yong; Xue, Yifeng; Hua, Shenbin; Wang, Kun

    2015-11-01

    This paper presents the scenario forecast of global atmospheric antimony (Sb) emissions from anthropogenic activities till 2050. The projection scenarios are built based on the comprehensive global antimony emission inventory for the period 1995-2010 which is reported in our previous study. Three scenarios are set up to investigate the future changes of global antimony emissions as well as their source and region contribution characteristics. Trends of activity levels specified as 5 primary source categories are projected by combining the historical trend extrapolation with EIA International energy outlook 2013, while the source-specific dynamic emission factors are determined by applying transformed normal distribution functions. If no major changes in the efficiency of emission control are introduced and keep current air quality legislations (Current Legislation scenario), global antimony emissions will increase by a factor of 2 between 2010 and 2050. The largest increase in Sb emissions is projected from Asia due to large volume of nonferrous metals production and waste incineration. In case of enforcing the pollutant emission standards (Strengthened Control scenario), global antimony emissions in 2050 will stabilize with that of 2010. Moreover, we can anticipate further declines in Sb emissions for all continents with the best emission control performances (Maximum Feasible Technological Reduction scenario). Future antimony emissions from the top 10 largest emitting countries have also been calculated and source category contributions of increasing emissions of these countries present significant diversity. Furthermore, global emission projections in 2050 are distributed within a 1° × 1°latitude/longitude grid. East Asia, Western Europe and North America present remarkable differences in emission intensity under the three scenarios, which implies that source-and-country specific control measures are necessary to be implemented for abating Sb emissions from

  13. Noninferiority of Miltefosine Versus Meglumine Antimoniate for Cutaneous Leishmaniasis in Children

    PubMed Central

    Rubiano, Luisa Consuelo; Miranda, María Consuelo; Muvdi Arenas, Sandra; Montero, Luz Mery; Rodríguez-Barraquer, Isabel; Garcerant, Daniel; Prager, Martín; Osorio, Lyda; Rojas, Maria Ximena; Pérez, Mauricio; Nicholls, Ruben Santiago

    2012-01-01

    Background. Children have a lower response rate to antimonial drugs and higher elimination rate of antimony (Sb) than adults. Oral miltefosine has not been evaluated for pediatric cutaneous leishmaniasis. Methods. A randomized, noninferiority clinical trial with masked evaluation was conducted at 3 locations in Colombia where Leishmania panamensis and Leishmania guyanensis predominated. One hundred sixteen children aged 2–12 years with parasitologically confirmed cutaneous leishmaniasis were randomized to directly observed treatment with meglumine antimoniate (20 mg Sb/kg/d for 20 days; intramuscular) (n = 58) or miltefosine (1.8–2.5 mg/kg/d for 28 days; by mouth) (n = 58). Primary outcome was treatment failure at or before week 26 after initiation of treatment. Miltefosine was noninferior if the proportion of treatment failures was ≤15% higher than achieved with meglumine antimoniate (1-sided test, α = .05). Results. Ninety-five percent of children (111/116) completed follow-up evaluation. By intention-to-treat analysis, failure rate was 17.2% (98% confidence interval [CI], 5.7%–28.7%) for miltefosine and 31% (98% CI, 16.9%–45.2%) for meglumine antimoniate. The difference between treatment groups was 13.8%, (98% CI, −4.5% to 32%) (P = .04). Adverse events were mild for both treatments. Conclusions. Miltefosine is noninferior to meglumine antimoniate for treatment of pediatric cutaneous leishmaniasis caused by Leishmania (Viannia) species. Advantages of oral administration and low toxicity favor use of miltefosine in children. Clinical Trial Registration. NCT00487253. PMID:22238470

  14. The EM Earthquake Precursor

    NASA Astrophysics Data System (ADS)

    Jones, K. B., II; Saxton, P. T.

    2013-12-01

    Many attempts have been made to determine a sound forecasting method regarding earthquakes and warn the public in turn. Presently, the animal kingdom leads the precursor list alluding to a transmission related source. By applying the animal-based model to an electromagnetic (EM) wave model, various hypotheses were formed, but the most interesting one required the use of a magnetometer with a differing design and geometry. To date, numerous, high-end magnetometers have been in use in close proximity to fault zones for potential earthquake forecasting; however, something is still amiss. The problem still resides with what exactly is forecastable and the investigating direction of EM. After the 1989 Loma Prieta Earthquake, American earthquake investigators predetermined magnetometer use and a minimum earthquake magnitude necessary for EM detection. This action was set in motion, due to the extensive damage incurred and public outrage concerning earthquake forecasting; however, the magnetometers employed, grounded or buried, are completely subject to static and electric fields and have yet to correlate to an identifiable precursor. Secondly, there is neither a networked array for finding any epicentral locations, nor have there been any attempts to find even one. This methodology needs dismissal, because it is overly complicated, subject to continuous change, and provides no response time. As for the minimum magnitude threshold, which was set at M5, this is simply higher than what modern technological advances have gained. Detection can now be achieved at approximately M1, which greatly improves forecasting chances. A propagating precursor has now been detected in both the field and laboratory. Field antenna testing conducted outside the NE Texas town of Timpson in February, 2013, detected three strong EM sources along with numerous weaker signals. The antenna had mobility, and observations were noted for recurrence, duration, and frequency response. Next, two

  15. Microbial Methylation of Metalloids: Arsenic, Antimony, and Bismuth

    PubMed Central

    Bentley, Ronald; Chasteen, Thomas G.

    2002-01-01

    A significant 19th century public health problem was that the inhabitants of many houses containing wallpaper decorated with green arsenical pigments experienced illness and death. The problem was caused by certain fungi that grew in the presence of inorganic arsenic to form a toxic, garlic-odored gas. The garlic odor was actually put to use in a very delicate microbiological test for arsenic. In 1933, the gas was shown to be trimethylarsine. It was not until 1971 that arsenic methylation by bacteria was demonstrated. Further research in biomethylation has been facilitated by the development of delicate techniques for the determination of arsenic species. As described in this review, many microorganisms (bacteria, fungi, and yeasts) and animals are now known to biomethylate arsenic, forming both volatile (e.g., methylarsines) and nonvolatile (e.g., methylarsonic acid and dimethylarsinic acid) compounds. The enzymatic mechanisms for this biomethylation are discussed. The microbial conversion of sodium arsenate to trimethylarsine proceeds by alternate reduction and methylation steps, with S-adenosylmethionine as the usual methyl donor. Thiols have important roles in the reductions. In anaerobic bacteria, methylcobalamin may be the donor. The other metalloid elements of the periodic table group 15, antimony and bismuth, also undergo biomethylation to some extent. Trimethylstibine formation by microorganisms is now well established, but this process apparently does not occur in animals. Formation of trimethylbismuth by microorganisms has been reported in a few cases. Microbial methylation plays important roles in the biogeochemical cycling of these metalloid elements and possibly in their detoxification. The wheel has come full circle, and public health considerations are again important. PMID:12040126

  16. Mercury, arsenic, antimony, and selenium contents of sediment from the Kuskokwim River, Bethel, Alaska, USA

    USGS Publications Warehouse

    Belkin, H.E.; Sparck, H.M.

    1993-01-01

    The Kuskokwim River at Bethel, Alaska, drains a major mercury-antimony metallogenic province in its upper reaches and tributaries. Bethel (population 4000) is situated on the Kuskokwim floodplain and also draws its water supply from wells located in river-deposited sediment. A boring through overbank and floodplain sediment has provided material to establish a baseline datum for sediment-hosted heavy metals. Mercury (total), arsenic, antimony, and selenium contents were determined; aluminum was also determined and used as normalizing factor. The contents of the heavy metals were relatively constant with depth and do not reflect any potential enrichment from upstream contaminant sources. ?? 1993 Springer-Verlag.

  17. Composite thin-foil bandpass filter for EUV astronomy Titanium-antimony-titanium

    NASA Technical Reports Server (NTRS)

    Jelinsky, P.; Martin, C.; Kimble, R.; Bowyer, S.; Steele, G.

    1983-01-01

    Thin metallic foils of antimony and titanium have been investigated in an attempt to develop an EUV filter with a bandpass from 350 to 550 A. A composite filter has been developed composed of antimony sandwiched between two titanium foils. The transmissions of sample composite foils and of pure titanium foils from 130 to 1216 A are presented. The absorption coefficients of anatimony and titanium and the effect of titanium oxide on the transmission are derived. The composite filter has been found to be quite stable and mechanically rugged. Among other uses, the filter shows substantial promise for EUV astronomy.

  18. Experimental and clinical studies with a new antimonial preparation for the treatment of schistosomiasis

    PubMed Central

    Pedrique, Miguel Ron; Ercoli, Nicolò

    1971-01-01

    This paper presents the results of a clinical study in which a new antimony preparation—a chelate of dimethylcysteine with antimony sodium tartrate (”NAP”)—was administered intramuscularly at a total dosage of 2 g (5×400 mg, corresponding to 290 mg of Sb) to 400 patients with schistosomiasis. Among 108 patients in a rural population the treatment was on the whole well accepted (97% completed the intensive course of injections), thus indicating that NAP would be useful for the mass treatment of schistosomiasis. PMID:5317079

  19. Antimony distribution and mobility in topsoils and plants (Cytisus striatus, Cistus ladanifer and Dittrichia viscosa) from polluted Sb-mining areas in Extremadura (Spain).

    PubMed

    Murciego, A Murciego; Sánchez, A García; González, M A Rodríguez; Gil, E Pinilla; Gordillo, C Toro; Fernández, J Cabezas; Triguero, T Buyolo

    2007-01-01

    A study about topsoil antimony distribution and mobility from the soils to the biomass has been afforded in three abandoned Sb mining areas located at Extremadura. Physico-chemical characteristics of the soils and total antimony levels were measured in soils and autochthonous plant species (Cytisus striatus, Cistus ladanifer and Dittrichia viscosa). Comparison with corresponding values in reference areas isolated from the mining activities is discussed. Antimony mobility in the soils was estimated by measuring the water extractable fraction; low results were obtained for the three soil areas, with no statistical differences. Plant ability to accumulate antimony was estimated by use of plant accumulation coefficients (PAC). Seasonal (spring vs. autumn) effects on the antimony content in the plant species. Cytisus striatus from Mari Rosa mine presented antimony excluder characteristics, whereas Dittrichia viscosa specimens growing in San Antonio mine showed a significant antimony bioaccumulation.

  20. Speciation of antimony(III) and antimony(V) by electrothermal atomic absorption spectrometry after ultrasound-assisted emulsification of solidified floating organic drop microextraction.

    PubMed

    Wen, Shengping; Zhu, Xiashi

    2013-10-15

    A simple, sensitive and efficient method of ultrasound-assisted emulsification of solidified floating organic drop microextraction (USE-SFODME) coupled to electrothermal atomic absorption spectrometry for the speciation of antimony at different oxidation state Sb(III)/Sb(V) in environmental samples was established. In this method, the hydrophobic complex of Sb(III) with sodium diethyldithiocarbamate (DDTC) is extracted by 1-undecanol at pH 9.0, while Sb(V) remains in aqueous phase. Sb(V) content can be calculated by subtracting Sb(III) from the total antimony after reducing Sb(V) to Sb(III) by l-cysteine. Various factors affecting USE-SFODME including pH, extraction solvent and its volume, concentration of DDTC, sonication time, and extraction temperature were investigated. Under the optimized conditions, the calibration curve was linear in the range from 0.05 to 10.0 ng mL(-1), with the limit of detection (3σ) 9.89 ng L(-1) for Sb(III). The relative standard deviation for Sb(III) was 4.5% (n=9, c=1.0 ng mL(-1)). This method was validated against the certified reference materials (GSB 07-1376-2001, GBW07441), and applied to the speciation of antimony in environmental samples (soil and water samples) with satisfactory results.

  1. Electrodeposition and device incorporation of bismuth antimony nanowire arrays

    NASA Astrophysics Data System (ADS)

    Keyani, Jennifer

    Thermoelectric materials have the unique property where the application of a potential difference across the material results in the formation of a temperature gradient, and vice versa. There is continued interest in bulk thermoelectric materials for power generation and refrigeration applications, however these materials are not currently in widespread use due to their low conversion efficiency. It has been predicted that nanostructured thermoelectric materials will show enhanced performance over their bulk counterparts. In this study, bismuth antimony (Bi1-xSbx) nanowire arrays have been synthesized and assembled into devices in order to demonstrate an enhanced performance in nanostructured thermoelectric materials. Bi1-xSbx nanowire arrays were fabricated by potentiostatic electrodeposition into porous alumina templates from a dimethyl sulfoxide (DMSO) solution. The nanowire composition and texture were studied as a function of the electrodeposition conditions in order to maximize their thermoelectric performance. Energy dispersive spectrometry and electron microprobe analysis were used to study the nanowire composition as a function of the electroactive and non-electroactive species in solution. Texturing in the nanowire arrays was observed by X-ray diffraction and controlled by the applied voltage and presence of supporting electrolyte. The nanowire arrays were also optimized for device incorporation by maximizing the number of nanowires and minimizing their length distribution. The areal density of nanowire arrays was on the order of 1010 wires/cm2 due to the high density of pores in the alumina and the high degree to which those pores were filled with electrodeposited material. A narrow distribution of nanowire lengths was observed by scanning electron microscopy across millimeter-length portions of the arrays. A hybrid nanowire-bulk thermoelectric device was assembled after electrical contacts were electrodeposited over Bi1-xSbx nanowire arrays. Nickel was

  2. Different Products of the Reduction of (N),C,N-Chelated Antimony(III) Compounds: Competitive Formation of Monomeric Stibinidenes versus 1H-2,1-Benzazastiboles.

    PubMed

    Vránová, Iva; Alonso, Mercedes; Jambor, Roman; Růžička, Aleš; Turek, Jan; Dostál, Libor

    2017-02-16

    The reduction of N,C,N-chelated antimony(III) chlorides [C6 H3 -2,6-(CH=NR)2 ]SbCl2 (R=Ph (1), tBu (2), Dip (3); Dip=2,6-iPr2 C6 H3 ) with an appropriate amount of KC8 or Li[AlH4 ] resulted in the formation of rare examples of monomeric stibinidenes [C6 H3 -2,6-(CH=NR)2 ]Sb (R=Ph (4), tBu (5), Dip (6)). Similarly, the reduction of compounds 1 or 2 by two equivalents of K[B(sBu)3 H] led to the stibinidenes 4 and 5. In contrast, the analogous reaction of compound 3 resulted in the formation of an unprecedented stibinidene [C6 H3 -2-(CH=NR)-6-(CH2 NHR)]Sb (7) (R=Dip), in which the hydrogen atoms that come from the K[B(sBu)3 H] are incorporated into the ligand backbone. To gain further insight into this intriguing reactivity with K[B(sBu)3 H] and to assess the influence of the substitution at both the antimony atom and pendant substituents, we prepared compounds [C6 H3 -2-(CH=NDip)]Sb(Ph)Cl (8) and [C6 H2 -2-(CH=NDip)-4,6-(tBu)2 ]SbCl2 (9). The treatment of compound 8 with K[B(sBu)3 H] smoothly led to the 1-Ph-2-Dip-1H-2,1-benzazastibole (11), whereas the reaction of compound 9 with K[B(sBu)3 H] resulted in either tBu-substituted 1-Cl-2-Dip-1H-2,1-benzazastibole (13) or the formation of unprecedented Sb-Sb dimer bis(2-Dip-1H-2,1-benzazastibole) (12) depending on the reaction stoichiometry. The miscellaneous reactivity of antimony(III) precursors with reducing agents together with the structure and bonding of the resulting products has also been investigated from a theoretical point of view.

  3. Mechanisms of antimony adsorption onto soybean stover-derived biochar in aqueous solutions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Limited mechanistic knowledge is available to understand how biochar interacts with trace elements that exist predominantly as oxoanions, such as antimony (Sb). Soybean stover biochars were produced at 300 degrees C (SBC300) and 700 degrees C (SBC700), and were characterized by BET, Boehm titration,...

  4. Contrasting role of antimony and bismuth dopants on the thermoelectric performance of lead selenide.

    PubMed

    Lee, Yeseul; Lo, Shih-Han; Chen, Changqiang; Sun, Hui; Chung, Duck-Young; Chasapis, Thomas C; Uher, Ctirad; Dravid, Vinayak P; Kanatzidis, Mercouri G

    2014-05-02

    Increasing the conversion efficiency of thermoelectric materials is a key scientific driver behind a worldwide effort to enable heat to electricity power generation at competitive cost. Here we report an increased performance for antimony-doped lead selenide with a thermoelectric figure of merit of ~1.5 at 800 K. This is in sharp contrast to bismuth doped lead selenide, which reaches a figure of merit of <1. Substituting antimony or bismuth for lead achieves maximum power factors between ~23-27 μW cm(-1) K(-2) at temperatures above 400 K. The addition of small amounts (~0.25 mol%) of antimony generates extensive nanoscale precipitates, whereas comparable amounts of bismuth results in very few or no precipitates. The antimony-rich precipitates are endotaxial in lead selenide, and appear remarkably effective in reducing the lattice thermal conductivity. The corresponding bismuth-containing samples exhibit smaller reduction in lattice thermal conductivity.

  5. Liposomal amphotericin B versus pentavalent antimony salts for visceral Leishmania in children.

    PubMed

    Apa, Hurşit; Devrim, İlker; Bayram, Nuri; Deveci, Reyhan; Demir-Özek, Gülcihan; Cartı, Özgür Umaç

    2013-01-01

    The aim of this study was to investigate the efficacy of a 21-day schedule of liposomal amphotericin B compared to pentavalent antimony salts in the treatment of patients during a first episode of visceral leishmaniasis. In this study, 17 cases of visceral leishmaniasis admitted to Behçet Uz Children's Hospital between January 2005 and April 2012 were reviewed retrospectively. The study group was composed of 11 males (64.7%) and 6 females (35.3%). One group included 11 patients who were treated with pentavalent antimony salts, sodium stibogluconate or meglumine antimoniate, intramuscularly for 28 days. The second group was treated with amphotericin B intravenously at a dosage of 3 mg/kg on days 1-5, 10 and 21 (a cumulative dose of 21 mg/kg/day). While pentavalent antimony salts were found to increase biochemical and hematological findings, liposomal amphotericin B was responsible for rapid recovery in fever and shorter hospital stay. As a result, our study shows the advantages of both medications independent of their costs.

  6. An Insight into Sodiation of Antimony from First-Principles Crystal Structure Prediction

    NASA Astrophysics Data System (ADS)

    Caputo, Riccarda

    2016-02-01

    Elemental antimony has recently become an attractive anode material for potential application in rechargeable sodium-ion batteries. I present a first-principles study of the structure-composition dependence of the Na-Sb system for both sodiation and desodiation processes. The enthalpy of reaction of x moles of sodium with the hexagonal structure of antimony reveals several stable crystal structures for 0 < x ≤ 3, with variable composition states for 1.25 < x < 2.75. The direct and reverse reactions pass through similar states in terms of enthalpy of formation and symmetry representation of the corresponding optimized structures, in particular for x = 1 and x = 3, confirming the two known phases, namely NaSb and Na3Sb. The calculations suggest that the optimal composition range for reversible sodiation of antimony is 1 < x ≤ 3, thus avoiding the global minimum at x = 1. This can help to rationalize the structure-composition dependence of the electrochemical performance of antimony in Na-ion batteries.

  7. Nanostructured Carbon/Antimony Composites as Anode Materials for Lithium-Ion Batteries with Long Life.

    PubMed

    Cheng, Yong; Yi, Zheng; Wang, Chunli; Wang, Lidong; Wu, Yaoming; Wang, Limin

    2016-08-05

    A series of nanostructured carbon/antimony composites have been successfully synthesized by a simple sol-gel, high-temperature carbon thermal reduction process. In the carbon/antimony composites, antimony nanoparticles are homogeneously dispersed in the pyrolyzed nanoporous carbon matrix. As an anode material for lithium-ion batteries, the C/Sb10 composite displays a high initial discharge capacity of 1214.6 mAh g(-1) and a reversible charge capacity of 595.5 mAh g(-1) with a corresponding coulombic efficiency of 49 % in the first cycle. In addition, it exhibits a high reversible discharge capacity of 466.2 mAh g(-1) at a current density of 100 mA g(-1) after 200 cycles and a high rate discharge capacity of 354.4 mAh g(-1) at a current density of 1000 mA g(-1) . The excellent cycling stability and rate discharge performance of the C/Sb10 composite could be due to the uniform dispersion of antimony nanoparticles in the porous carbon matrix, which can buffer the volume expansion and maintain the integrity of the electrode during the charge-discharge cycles.

  8. Dismantling and chemical characterization of spent Peltier thermoelectric devices for antimony, bismuth and tellurium recovery.

    PubMed

    Balva, Maxime; Legeai, Sophie; Garoux, Laetitia; Leclerc, Nathalie; Meux, Eric

    2017-04-01

    Major uses of thermoelectricity concern refrigeration purposes, using Peltier devices, mainly composed of antimony, bismuth and tellurium. Antimony was identified as a critical raw material by EU and resources of bismuth and tellurium are not inexhaustible, so it is necessary to imagine the recycling of thermoelectric devices. That for, a complete characterization is needed, which is the aim of this work. Peltier devices were manually dismantled in three parts: the thermoelectric legs, the alumina plates on which remain the electrical contacts and the silicone paste used to connect the plates. The characterization was performed using five Peltier devices. It includes mass balances of the components, X-ray diffraction analysis of the thermoelectric legs and elemental analysis of each part of the device. It appears that alumina represents 45% of a Peltier device in weight. The electrical contacts are mainly composed of copper and tin, and the thermoelectric legs of bismuth, tellurium and antimony. Thermoelectric legs appear to be Se-doped Bi2Te3 and (Bi0,5Sb1,5)Te3 for n type and p type semiconductors, respectively. This work shows that Peltier devices can be considered as a copper ore and that thermoelectric legs contain high amounts of bismuth, tellurium and antimony compared to their traditional resources.

  9. Copper(II) and nickel(II) complexes of benzyloxybenzaldehyde-4-phenyl-3-thiosemicarbazone: Synthesis, characterization and biological activity

    NASA Astrophysics Data System (ADS)

    Prathima, B.; Subba Rao, Y.; Adinarayana Reddy, S.; Reddy, Y. P.; Varada Reddy, A.

    2010-09-01

    Benzyloxybenzaldehyde-4-phenyl-3-thiosemicarbazone ligand (L) has been synthesized from benzyloxybenzaldehyde and 4-phenyl-3-thiosemicarbazide. Complexes of this ligand with chlorides of Cu(II) and Ni(II) have been prepared. The structure of the ligand (L) is proposed based on elemental analysis, IR and 1H NMR spectra. Its complexes with Cu(II) and Ni(II) ions are characterized from the studies of electronic as well as EPR spectra. On the basis of electronic and EPR studies, rhombically distorted octahedral structure has been proposed for Cu(II) complex while the Ni(II) complex has been found to acquire an octahedral structure. The ligand and their metal complexes have been tested in vitro for their biological effects. Their antibacterial activities against Gram-negative bacteria ( Escherichia coli and Klebsiella pneumoniae) and Gram-positive bacteria ( Staphylococcus aureus and Bacillus subtilis) have been investigated. The prepared metal complexes exhibit higher antibacterial activities than the parent ligand. The in vitro antioxidant activity of free ligand and its metal(II) complexes have also been investigated and the results however reveal that the ligand exhibits greater antioxidant activity than its complexes.

  10. Induction of Early Autophagic Process on Leishmania amazonensis by Synergistic Effect of Miltefosine and Innovative Semi-synthetic Thiosemicarbazone.

    PubMed

    Scariot, Débora B; Britta, Elizandra A; Moreira, Amanda L; Falzirolli, Hugo; Silva, Cleuza C; Ueda-Nakamura, Tânia; Dias-Filho, Benedito P; Nakamura, Celso V

    2017-01-01

    Drug combination therapy is a current trend to treat complex diseases. Many benefits are expected from this strategy, such as cytotoxicity decrease, retardation of resistant strains development, and activity increment. This study evaluated in vitro combination between an innovative thiosemicarbazone molecule - BZTS with miltefosine, a drug already consolidated in the leishmaniasis treatment, against Leishmania amazonensis. Cytotoxicity effects were also evaluated on macrophages and erythrocytes. Synergistic antileishmania effect and antagonist cytotoxicity were revealed from this combination therapy. Mechanisms of action assays were performed in order to investigate the main cell pathways induced by this treatment. Mitochondrial dysfunction generated a significant increase of reactive oxygen and nitrogen species production, causing severe cell injuries and promoting intense autophagy process and consequent apoptosis cell death. However, this phenomenon was not strong enough to promote dead in mammalian cell, providing the potential selective effect of the tested combination for the protozoa. Thus, the results confirmed that drugs involved in distinct metabolic routes are promising agents for drug combination therapy, promoting a synergistic effect.

  11. Synthesis, spectroscopic, anticancer and antibacterial studies of Ni(II) and Cu(II) complexes with 2-carboxybenzaldehyde thiosemicarbazone

    NASA Astrophysics Data System (ADS)

    Chandra, Sulekh; Vandana

    2014-08-01

    Ni(II) and Cu(II) complexes of 2-carboxybenzaldehyde thiosemicarbazone (L) were synthesized and investigated by their spectral and analytical data. These newly synthesized complexes have a composition of M(L)X(H2O)2 (where M = Ni(II), Cu(II) and X = Cl-, NO3-, CH3COO-) and (L) is the tridentate Schiff base ligand. The ligand and its complexes have been characterized on the basis of analytical, molar conductivity, magnetic susceptibility measurements, FT-IR, ESR, 1H NMR and electronic spectral analysis. All the compounds were non-electrolytic in nature. On the basis of spectral studies an octahedral geometry has been assigned for Ni(II) and a tetragonal geometry for Cu(II) complexes. The ligand and its metal complexes were screened for their anticancer studies against human breast cancer cell lines MCF-7 and calculated minimum inhibitory concentration and also for antibacterial activity using Kirby-Bauer single disk susceptibility test.

  12. Synthesis and evaluation of simple naked-eye colorimetric chemosensors for anions based on azo dye-thiosemicarbazones.

    PubMed

    Radchatawedchakoon, Widchaya; Sangsuwan, Withsakorn; Kruanetr, Senee; Sakee, Uthai

    2014-01-01

    A series of novel, highly selective azo dye-thiosemicarbazones based anion sensors (3e-f) have been synthesized from the condensation reaction between thiosemicarbazide and six different azo salicylaldehydes. The structure of the sensors was confirmed by spectroscopic methods. The selectivity and sensitivity in the recognition for acetate anion over other anions such as fluoride, chloride, iodide and dihydrogenphosphate anions were determined by naked-eyes and UV-vis spectra. The color of the solution containing sensor had an obvious change from light yellow to orange only after the addition of acetate anion in aqueous solution (water/dimethylsulfoxide, 7:3, v/v) while other anions did not cause obvious color change. The anion recognition property of the receptor via proton-transfer is monitored by UV-vis titration and (1)H NMR spectroscopy. Under condition in aqueous solution of sensor 3e (water/dimethylsulfoxide, 7:3, v/v), linearity range for the quantification of acetate anion was 1-22 μM and limit of detection (LOD) of acetate anion was 0.71 μM.

  13. Transition metal complexes of Vanillin- 4N-(2-pyridyl) thiosemicarbazone (H 2VPT); thermal, structural and spectroscopic studies

    NASA Astrophysics Data System (ADS)

    El-Reash, Gaber Abu; El-Ayaan, Usama; Gabr, I. M.; El-Rachawy, El-Bastawesy

    2010-04-01

    The present work carried out a study on the ligational behavior of the new ligand, Vanillin- 4N-(2-pyridyl) thiosemicarbazone (H 2VPT) 1 towards some transition metal ions namely, Mn 2+, Co 2+, Ni 2+, Cu 2+, Zn 2+,Cd 2+, Hg 2+ and U 6+. These complexes namely [Mn(HVPT)Cl] 2, [Co(VPT)(H 2O)] 2H 2O 3, [Ni(HVPT)Cl(H 2O)] 4, [Cu(HVPT)Cl(H 2O)] 5, [Zn(VPT)(H 2O)]H 2O 6, [Cd(HVPT)Cl(H 2O)] 7, [Hg(VPT)(H 2O)]H 2O 8 and [UO 2(H 2VPT)(OAc) 2]H 2O 9, were characterized by elemental analysis, spectral (IR, 1H NMR and UV-vis) and magnetic moment measurements. The suggested structures were confirmed by applying geometry optimization and conformational analysis. Thermal properties and decomposition kinetics of all compounds are investigated. The interpretation, mathematical analysis and evaluation of kinetic parameters ( E, A, Δ H, Δ S and Δ G) of all thermal decomposition stages have been evaluated using Coats-Redfern equation. ESR spectra of [Cu(HVPT)Cl]H 2O at room temperature show broad signal, indicating spin-exchange interactions between copper(II) ions.

  14. Induction of Early Autophagic Process on Leishmania amazonensis by Synergistic Effect of Miltefosine and Innovative Semi-synthetic Thiosemicarbazone

    PubMed Central

    Scariot, Débora B.; Britta, Elizandra A.; Moreira, Amanda L.; Falzirolli, Hugo; Silva, Cleuza C.; Ueda-Nakamura, Tânia; Dias-Filho, Benedito P.; Nakamura, Celso V.

    2017-01-01

    Drug combination therapy is a current trend to treat complex diseases. Many benefits are expected from this strategy, such as cytotoxicity decrease, retardation of resistant strains development, and activity increment. This study evaluated in vitro combination between an innovative thiosemicarbazone molecule – BZTS with miltefosine, a drug already consolidated in the leishmaniasis treatment, against Leishmania amazonensis. Cytotoxicity effects were also evaluated on macrophages and erythrocytes. Synergistic antileishmania effect and antagonist cytotoxicity were revealed from this combination therapy. Mechanisms of action assays were performed in order to investigate the main cell pathways induced by this treatment. Mitochondrial dysfunction generated a significant increase of reactive oxygen and nitrogen species production, causing severe cell injuries and promoting intense autophagy process and consequent apoptosis cell death. However, this phenomenon was not strong enough to promote dead in mammalian cell, providing the potential selective effect of the tested combination for the protozoa. Thus, the results confirmed that drugs involved in distinct metabolic routes are promising agents for drug combination therapy, promoting a synergistic effect. PMID:28270805

  15. A study on the alkaline hydrolysis of isatin-β-thiosemicarbazone by capillary electrophoresis with enhanced sample loadability.

    PubMed

    Kruk, Pavol; Stankovičová, Henrieta; Bodor, Róbert; Gáplovský, Anton; Masár, Marián

    2012-05-11

    An analytical potential of capillary zone electrophoresis (CZE) with enhanced sample loadability (a 200nL injection volume) in determination of alkaline hydrolysis products of isatin-β-thiosemicarbazone (IBT), a compound with important biological activity, has been studied. The CZE separation conditions for a complete resolution of transformation products, i.e. 2-aminophenylglyoxalate, 2-(2-aminophenyl)-2-semicarbazonoethane, anthranilate and E-Z geometric isomers of 2-(2-aminophenyl)-2-thiosemicarbazonoethane, have been optimized. CZE separations with UV detection at 240 nm were performed using glycine running buffer at high pH (9.2) and containing an uncharged β-cyclodextrin as a complexing agent. High sensitivity (with detection limits ranging from 0.1 to 1.2 μM), good repeatability (RSD of migration times less than 0.4% and 0.4-3.4% RSD of peak areas) and linearity over two orders of magnitude were achieved for the compounds studied. The employed CZE method, characterized by simple sample handling (only dilution step needed) and total analysis time of less than 15 min, has been applied successfully to time monitoring of the transformation of IBT in alkaline media. Under optimized CZE conditions, the effect of pH of reaction media, implemented by different concentration of NaOH (0.1-100mM), on the course of the alkaline hydrolysis of IBT was studied in this respect, as well.

  16. Synthesis and evaluation of simple naked-eye colorimetric chemosensors for anions based on azo dye-thiosemicarbazones

    NASA Astrophysics Data System (ADS)

    Radchatawedchakoon, Widchaya; Sangsuwan, Withsakorn; Kruanetr, Senee; Sakee, Uthai

    2014-03-01

    A series of novel, highly selective azo dye-thiosemicarbazones based anion sensors (3e-f) have been synthesized from the condensation reaction between thiosemicarbazide and six different azo salicylaldehydes. The structure of the sensors was confirmed by spectroscopic methods. The selectivity and sensitivity in the recognition for acetate anion over other anions such as fluoride, chloride, iodide and dihydrogenphosphate anions were determined by naked-eyes and UV-vis spectra. The color of the solution containing sensor had an obvious change from light yellow to orange only after the addition of acetate anion in aqueous solution (water/dimethylsulfoxide, 7:3, v/v) while other anions did not cause obvious color change. The anion recognition property of the receptor via proton-transfer is monitored by UV-vis titration and 1H NMR spectroscopy. Under condition in aqueous solution of sensor 3e (water/dimethylsulfoxide, 7:3, v/v), linearity range for the quantification of acetate anion was 1-22 μM and limit of detection (LOD) of acetate anion was 0.71 μM.

  17. Copper(II) and nickel(II) complexes of benzyloxybenzaldehyde-4-phenyl-3-thiosemicarbazone: Synthesis, characterization and biological activity.

    PubMed

    Prathima, B; Subba Rao, Y; Adinarayana Reddy, S; Reddy, Y P; Varada Reddy, A

    2010-09-15

    Benzyloxybenzaldehyde-4-phenyl-3-thiosemicarbazone ligand (L) has been synthesized from benzyloxybenzaldehyde and 4-phenyl-3-thiosemicarbazide. Complexes of this ligand with chlorides of Cu(II) and Ni(II) have been prepared. The structure of the ligand (L) is proposed based on elemental analysis, IR and (1)H NMR spectra. Its complexes with Cu(II) and Ni(II) ions are characterized from the studies of electronic as well as EPR spectra. On the basis of electronic and EPR studies, rhombically distorted octahedral structure has been proposed for Cu(II) complex while the Ni(II) complex has been found to acquire an octahedral structure. The ligand and their metal complexes have been tested in vitro for their biological effects. Their antibacterial activities against Gram-negative bacteria (Escherichia coli and Klebsiella pneumoniae) and Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis) have been investigated. The prepared metal complexes exhibit higher antibacterial activities than the parent ligand. The in vitro antioxidant activity of free ligand and its metal(II) complexes have also been investigated and the results however reveal that the ligand exhibits greater antioxidant activity than its complexes.

  18. Synthesis and evaluation of isatin-β-thiosemicarbazones as novel agents against antibiotic-resistant Gram-positive bacterial species.

    PubMed

    Zhang, Xu-Meng; Guo, Hui; Li, Zai-Shun; Song, Fu-Hang; Wang, Wei-Min; Dai, Huan-Qin; Zhang, Li-Xin; Wang, Jian-Guo

    2015-08-28

    Methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE) have caused an increasing mortality rate, which means that antibiotic resistance is becoming an important health issue. In the course to screen new agents for resistant bacteria, we identified that a series of isatin-β-thiosemicarbazones (IBTs) could inhibit the growth of MRSA and VRE. This was the first time that the "familiar" IBT compounds exhibited significant anti Gram-positive pathogen activity. Against a clinical isolated MRSA strain, 20 of the 51 synthesized compounds showed minimum inhibitory concentration (MIC) data of 0.78 mg/L and another 12 novel compounds had MICs of 0.39 mg/L. Moreover, these compounds also inhibited Enterococcus faecalis and VRE at similar levels, indicating that IBTs might have different mode of action compared with vancomycin. For these IBTs, comparative field analysis (CoMFA) models were further established to understand the structure-activity relationships in order to design new compounds from steric and electrostatic contributions. This work has suggested that IBTs can be considered as potential lead compounds to discover antibacterial inhibitors to combat drug resistance.

  19. Human biomonitoring of arsenic and antimony in case of an elevated geogenic exposure.

    PubMed Central

    Gebel, T W; Suchenwirth, R H; Bolten, C; Dunkelberg, H H

    1998-01-01

    Part of the northern Palatinate region in Germany is characterized by elevated levels of arsenic and antimony in the soil due to the presence of ore sources and former mining activities. In a biomonitoring study, 218 residents were investigated for a putative increased intake of these elements. Seventy-six nonexposed subjects in a rural region in south lower Saxony were chosen as the reference group. Urine and scalp hair samples were obtained as surrogates to determine the internal exposures to arsenic and antimony. The analyses were performed using graphite furnace atomic absorption spectrometry except for arsenic in urine, which was determined by the hydride technique. This method does not detect organoarsenicals from seafood, which are not toxicologically relevant. In the northern Palatinate subjects, slightly elevated arsenic contents in urine and scalp hair (presumably not hazardous) could be correlated with an increased arsenic content in the soil. On the other hand, the results did not show a correlation between the antimony contents in the soil of the housing area and those in urine and hair. Except for antimony in scalp hair, age tended to be associated with internal exposures to arsenic and antimony in both study groups. Consumption of seafood had a slight impact on the level of urinary arsenic, which is indicative of the presence of low quantities of inorganic arsenicals and dimethylarsinic acid in seafood. The arsenic and antimony contents in scalp hair were positively correlated with the 24-hr arsenic excretion in urine. However, antimony in scalp hair was not correlated with seafood consumption as was arsenic in scalp hair and in urine. This indicated the existence of unidentified common pathways of exposure contributing to the alimentary body burden. Short time peaks in the 24-hr excretion of arsenic in urine, which could not be assigned to a high consumption of seafood, were detected for six study participants. This suggests that additional factors

  20. Novel and potent anti-tumor and anti-metastatic di-2-pyridylketone thiosemicarbazones demonstrate marked differences in pharmacology between the first and second generation lead agents

    PubMed Central

    Sestak, Vit; Stariat, Jan; Cermanova, Jolana; Potuckova, Eliska; Chladek, Jaroslav; Roh, Jaroslav; Bures, Jan; Jansova, Hana; Prusa, Petr; Sterba, Martin; Micuda, Stanislav; Simunek, Tomas; Kalinowski, Danuta S.; Richardson, Des R.; Kovarikova, Petra

    2015-01-01

    Di(2-pyridyl)ketone 4,4-dimethyl-3-thiosemicarbazone (Dp44mT) and di(2-pyridyl)ketone 4-cyclohexyl-4-methyl-3-thiosemicarbazone (DpC) are novel, highly potent and selective anti-tumor and anti-metastatic drugs. Despite their structural similarity, these agents differ in their efficacy and toxicity in-vivo. Considering this, a comparison of their pharmacokinetic and pharmaco/toxico-dynamic properties was conducted to reveal if these factors are involved in their differential activity. Both compounds were administered to Wistar rats intravenously (2 mg/kg) and their metabolism and disposition were studied using UHPLC-MS/MS. The cytotoxicity of both thiosemicarbazones and their metabolites was also examined using MCF-7, HL-60 and HCT116 tumor cells and 3T3 fibroblasts and H9c2 cardiac myoblasts. Their intracellular iron-binding ability was characterized by the Calcein-AM assay and their iron mobilization efficacy was evaluated. In contrast to DpC, Dp44mT undergoes rapid demethylation in-vivo, which may be related to its markedly faster elimination (T1/2 = 1.7 h for Dp44mT vs. 10.7 h for DpC) and lower exposure. Incubation of these compounds with cancer cells or cardiac myoblasts did not result in any significant metabolism in-vitro. The metabolism of Dp44mT in-vivo resulted in decreased anti-cancer activity and toxicity. In conclusion, marked differences in the pharmacology of Dp44mT and DpC were observed and highlight the favorable pharmacokinetics of DpC for cancer treatment. PMID:26623727

  1. Synthesis and characterization of mixed-ligand diimine-piperonal thiosemicarbazone complexes of ruthenium(II): Biophysical investigations and biological evaluation as anticancer and antibacterial agents

    PubMed Central

    Beckford, Floyd A.; Thessing, Jeffrey; Shaloski, Michael; Mbarushimana, P. Canisius; Brock, Alyssa; Didion, Jacob; Woods, Jason; Gonzalez-Sarrías, Antonio; Seeram, Navindra P.

    2011-01-01

    We have used a novel microwave-assisted method developed in our laboratories to synthesize a series of ruthenium-thiosemicarbazone complexes. The new thiosemicarbazone ligands are derived from benzo[d][1,3]dioxole-5-carbaldehyde (piperonal) and the complexes are formulated as [(diimine)2Ru(TSC)](PF6)2 (where the TSC is the bidentate thiosemicarbazone ligand). The diimine in the complexes is either 2,2'-bipyridine or 1,10-phenanthroline. The complexes have been characterized by spectroscopic means (NMR, IR and UV-Vis) as well as by elemental analysis. We have studied the biophysical characteristics of the complexes by investigating their anti-oxidant ability as well as their ability to disrupt the function of the human topoisomerase II enzyme. The complexes are moderately strong binders of DNA with binding constants of 104 M−1. They are also strong binders of human serum albumin having binding constants on the order of 104 M−1. The complexes show good in vitro anticancer activity against human colon cancer cells, Caco-2 and HCT-116 and indeed show some cytotoxic selectivity for cancer cells. The IC50 values range from 7 – 159 μM (after 72 h drug incubation). They also have antibacterial activity against Gram-positive strains of pathogenic bacteria with IC50 values as low as 10 μM; little activity was seen against Gram-negative strains. It has been established that all the compounds are catalytic inhibitors of human topoisomerase II. PMID:21552381

  2. Metal-catalysed oxidation processes in thiosemicarbazones: new complexes with the ligand N-{2-([4-N-ethylthiosemicarbazone]methyl)phenyl}-p-toluenesulfonamide.

    PubMed

    Pedrido, Rosa; Romero, María J; Bermejo, Manuel R; González-Noya, Ana M; García-Lema, Iria; Zaragoza, Guillermo

    2008-01-01

    The coordination behaviour of a new thiosemicarbazone Schiff-base building block, N-{2-([4-N-ethylthiosemicarbazone]methyl)phenyl}-p-toluenesulfonamide, H2L1 (1), incorporating a bulky tosyl group, towards Mn II, Fe II, Co II, Ni II, Cu II, Zn II, Cd II, Ag I, Sn II, and Pb II has been investigated by means of an electrochemical preparative procedure. Most metal complexes of L1 have the general formula [M(L1)]2.nX (M=Mn, Fe, Co, Ni, Cu, Cd, Pb; n=0-4, X=H2O or CH3CN), as confirmed by the structure of [Pb(L1)]2 (15), in which the lone pair on lead is stereochemically active. This lead(II) complex shows an intense fluorescence emission with a quantum yield of 0.13. In the case of silver, the complex formed was found to possess a stoichiometry of [Ag2(L1)]2.3H2O. During reactions with manganese and copper metals, interesting catalysed processes have been found to take place, with remarkable consequences regarding the ligand skeleton structure. In synthesising the manganese complex, we obtained an unexpected dithiolate thiosemicarbazone tosyl ligand, H2L2, as a side-product, which has been fully characterised, including by X-ray diffraction analysis. In the case of copper, the solid complex has the formula [CuL1]2, but the crystallised product shows the copper atoms coordinated to a new cyclised thiosemicarbazone ligand, H2L3, as in the structures of the complexes [Cu(L3)]2.CH3CN (8) and [Cu(L3)(H2O)]2.CH3CN.H2O (9). The zinc complex [Zn(L1)]4 (12) displays a particular tetranuclear zeolite-type structure capable of hosting small molecules or ions, presumably through hydrogen bonding.

  3. A 119Sn Mössbauer Study of Tin(IV) Complexes of 2- and 4-Benzoylpyridine Thiosemicarbazone and 4-Benzoylpyridine Semicarbazone

    NASA Astrophysics Data System (ADS)

    Pérez-Rebolledo, Anayive; Ardisson, José D.; de Lima, Geraldo M.; Macedo, Waldemar A. A.; Beraldo, Heloisa

    2005-06-01

    A 119Sn Mössbauer study was carried out of tin(IV) complexes with 2-benzoylpyridine thiosemicarbazone (H2Bz4DH) and its N(4)-methyl (H2Bz4M) and N(4)-phenyl (H2Bz4Ph) derivatives: [Sn(2Bz4DH)Cl3] (1), [Sn(2Bz4DH)PhCl2] (2), [Sn(2Bz4M)Cl3] (3), [H22Bz4M]2[Ph2SnCl4] (4), [Sn(2Bz4Ph)PhCl2] (5), [Sn(2Bz4Ph)Ph2Cl] (6), in which H2Bz4R stands for the neutral ligand and 2Bz4R stands for the anionic thiosemicarbazone. In addition, 119Sn Mössbauer studies of the tin(IV) complexes [Sn(H4Bz4DH)2Cl4H2O] (7), [Sn(H4BzPS)2Cl4H2O] (8) with 4-benzoylpyridine thiosemicarbazone (H4Bz4DH) and the correspondent semicarbazone (H4BzPS) were performed. The isomer shifts decrease upon coordination due to the variation in the percentage of s character as tin changes from approximately sp3 hybridization in the tin salts to sp3d2 in the octahedral or sp3d3 in the heptahedral complexes. The Mössbauer parameters of compound (4) showed the existence of two tin(IV) sites, which have been attributed to the presence of the cis and trans isomers.

  4. Identified EM Earthquake Precursors

    NASA Astrophysics Data System (ADS)

    Jones, Kenneth, II; Saxton, Patrick

    2014-05-01

    Many attempts have been made to determine a sound forecasting method regarding earthquakes and warn the public in turn. Presently, the animal kingdom leads the precursor list alluding to a transmission related source. By applying the animal-based model to an electromagnetic (EM) wave model, various hypotheses were formed, but the most interesting one required the use of a magnetometer with a differing design and geometry. To date, numerous, high-end magnetometers have been in use in close proximity to fault zones for potential earthquake forecasting; however, something is still amiss. The problem still resides with what exactly is forecastable and the investigating direction of EM. After a number of custom rock experiments, two hypotheses were formed which could answer the EM wave model. The first hypothesis concerned a sufficient and continuous electron movement either by surface or penetrative flow, and the second regarded a novel approach to radio transmission. Electron flow along fracture surfaces was determined to be inadequate in creating strong EM fields, because rock has a very high electrical resistance making it a high quality insulator. Penetrative flow could not be corroborated as well, because it was discovered that rock was absorbing and confining electrons to a very thin skin depth. Radio wave transmission and detection worked with every single test administered. This hypothesis was reviewed for propagating, long-wave generation with sufficient amplitude, and the capability of penetrating solid rock. Additionally, fracture spaces, either air or ion-filled, can facilitate this concept from great depths and allow for surficial detection. A few propagating precursor signals have been detected in the field occurring with associated phases using custom-built loop antennae. Field testing was conducted in Southern California from 2006-2011, and outside the NE Texas town of Timpson in February, 2013. The antennae have mobility and observations were noted for

  5. An interstellar precursor mission

    NASA Technical Reports Server (NTRS)

    Jaffe, L. D.; Ivie, C.; Lewis, J. C.; Lipes, R. G.; Norton, H. N.; Stearns, J. W.; Stimpson, L.; Weissman, P.

    1977-01-01

    A mission out of the planetary system, with launch about the year 2000, could provide valuable scientific data as well as test some of the technology for a later mission to another star. Primary scientific objectives for the precursor mission concern characteristics of the heliopause, the interstellar medium, stellar distances (by parallax measurements), low energy cosmic rays, interplanetary gas distribution, and mass of the solar system. Secondary objectives include investigation of Pluto. Candidate science instruments are suggested. Individual spacecraft systems for the mission were considered, technology requirements and problem areas noted, and a number of recommendations made for technology study and advanced development. The most critical technology needs include attainment of 50-yr spacecraft lifetime and development of a long-life NEP system.

  6. L- and D-proline thiosemicarbazone conjugates: coordination behavior in solution and the effect of copper(II) coordination on their antiproliferative activity.

    PubMed

    Milunovic, Miljan N M; Enyedy, Éva A; Nagy, Nóra V; Kiss, Tamás; Trondl, Robert; Jakupec, Michael A; Keppler, Bernhard K; Krachler, Regina; Novitchi, Ghenadie; Arion, Vladimir B

    2012-09-03

    Two enantiomerically pure thiosemicarbazone-proline conjugates with enhanced aqueous solubility, namely, 2-hydroxy-3-methyl-(S)-pyrrolidine-2-carboxylate-5-methylbenzaldehyde thiosemicarbazone [L-Pro-STSC or (S)-H(2)L] and 2-hydroxy-3-methyl-(R)-pyrrolidine-2-carboxylate-5-methylbenzaldehyde thiosemicarbazone [D-Pro-STSC or (R)-H(2)L] have been synthesized and characterized by elemental analysis, spectroscopic methods (UV-vis and (1)H and (13)C NMR), and electrospray ionization mass spectrometry. The metal complexation behavior of L-Pro-STSC, stoichiometry, and thermodynamic stability of iron(II), iron(III), copper(II), and zinc(II) complexes in 30% (w/w) dimethyl sulfoxide/H(2)O solvent mixture have been studied by pH-potentiometric, UV-vis-spectrophotometric, circular dichroism, electron paramagnetic resonance, (1)H NMR spectroscopic, and spectrofluorimetric measurements. By the reaction of CuCl(2)·2H(2)O with (S)-H(2)L and (R)-H(2)L, respectively, the complexes [Cu[(S)-H(2)L]Cl]Cl and [Cu[(R)-H(2)L]Cl]Cl have been prepared and comprehensively characterized. An X-ray diffraction study of [Cu[(R)-H(2)L]Cl]Cl showed the formation of a square-planar copper(II) complex, which builds up stacks with interplanar separation of 3.3 Å. The antiproliferative activity of two chiral ligands and their corresponding copper(II) complexes has been tested in two human cancer cell lines, namely, SW480 (colon carcinoma) and CH1 (ovarian carcinoma). The thiosemicarbazone-proline conjugates L- and D-Pro-STSC show only moderate cytotoxic potency with IC(50) values of 62 and 75 μM, respectively, in CH1 cells and >100 μM in SW480 cells. However, the corresponding copper(II) complexes are 13 and 5 times more potent in CH1 cells, based on a comparison of IC(50) values, and in SW480 cells the increase in the antiproliferative activity is even higher. In both tested cell lines, L-Pro-STSC as well as its copper(II) complex show slightly stronger antiproliferative activity than the

  7. Biochemical removal of HAP precursors from coal. Technical progress report, January--March 1996

    SciTech Connect

    1996-08-01

    Shake flask bioleaching tests were conducted with Pittsburgh NO. 8 and Indiana No. 5 coal. Bacteria removed pyritic sulfur from both coals at maximum rates of 5 to 9% per day, which was about 20 times the abiotic rate of pyrite oxidation. Concentrations of inorganic hazardous air pollutant (HAP) precursor elements in starting coal, bioleached coal and in leach solutions were measured. Of the 13 HAP precursors, significant amounts of arsenic, cobalt, cadmium, manganese, and nickel were removed from both coals by bacterial activity and also by the acidic leach solutions in control flasks. Little or no mercury, lead, beryllium, chromium, antimony, fluorine or chlorine was removed from the coals. Selenium was bioleached from both coals as determined by analysis of Se in leach solutions. However, analyses of Se in starting coal and in coal residues remains problematic. With very few exceptions, mass balances for the HAP precursors ranged from 80 to 120%. Improved analytical methods were developed for measuring concentrations of Hg, Se, As, and Sb in coal. Shake flask tests with pyrite oxidizing bacteria were conducted on Pittsburgh No. 8 and Indiana No. 5 coal. Concentrations of HAP precursors in the starting coal, leach solutions, and final coal residues were measured. A column leaching-rotating biological contactor (RBC) unit was assembled and a column leach test with Pittsburgh No. 8 coal was begun.

  8. Generation of Nonlinear Vortex Precursors

    NASA Astrophysics Data System (ADS)

    Chen, Yue-Yue; Feng, Xun-Li; Liu, Chengpu

    2016-07-01

    We numerically study the propagation of a few-cycle pulse carrying orbital angular momentum (OAM) through a dense atomic system. Nonlinear precursors consisting of high-order vortex harmonics are generated in the transmitted field due to carrier effects associated with ultrafast Bloch oscillation. The nonlinear precursors survive to propagation effects and are well separated with the main pulse, which provides a straightforward way to measure precursors. By virtue of carrying high-order OAM, the obtained vortex precursors as information carriers have potential applications in optical information and communication fields where controllable loss, large information-carrying capacity, and high speed communication are required.

  9. Selective speciation of inorganic antimony on tetraethylenepentamine bonded silica gel column and its determination by graphite furnace atomic absorption spectrometry.

    PubMed

    Mendil, Durali; Bardak, Hilmi; Tuzen, Mustafa; Soylak, Mustafa

    2013-03-30

    A speciation system for antimony (III) and antimony (V) ions that based on solid phase extraction on tetraethylenepentamine bonded silica gel has been established. Antimony was determined by graphite furnace atomic absorption spectrometry (GF-AAS). Analytical conditions including pH, sample volume, etc., were studied for the quantitative recoveries of Sb (III) and Sb (V). Matrix effects on the recovery were also investigated. The recovery values and detection limit for antimony (III) at optimal conditions were found as >95% and 0.020 μg L(-1), respectively. Preconcentration factor was calculated as 50. The capacity of adsorption for the tetraethylenepentamine bonded silica gel was 7.9 mg g(-1). The validation was checked by analysis of NIST SRM 1573a Tomato laves and GBW 07605 Tea certified reference materials. The procedure was successfully applied to speciation of antimony in tap water, mineral water and spring water samples. Total antimony was determined in refined salt, unrefined salt, black tea, rice, tuna fish and soil samples after microwave digestion and presented enrichment method combination.

  10. Fast sequential determination of antimony and lead in pewter alloys using high-resolution continuum source flame atomic absorption spectrometry.

    PubMed

    Dessuy, Morgana B; de Jesus, Robson M; Brandao, Geovani C; Ferreira, Sergio L C; Vale, Maria Goreti R; Welz, Bernhard

    2013-01-01

    A simple method has been developed to determine antimony and lead in pewter alloy cups produced in Brazil, using fast sequential determination by high-resolution continuum source flame atomic absorption spectrometry. The samples were dissolved in HCl and H(2)O(2), employing a cold finger system in order to avoid analyte losses. The main resonance line of lead at 217.001 nm and a secondary line of antimony at 212.739 nm were used. The limits of detection for lead and antimony were 0.02 and 5.7 mg L(-1), respectively. The trueness of the method was established by recovery tests and comparing the results obtained by the proposed method with those obtained by inductively coupled plasma optical emission spectrometry. The results were compared using a student's t-test and there was no significant difference at a 95% confidence interval. With the developed methods, it was possible to determine accurately antimony and lead in pewter samples. The lead concentration found in the analysed samples was around 1 mg g(-1), which means that they are not lead free; however, the content was below the maximum allowed level of 5 mg g(-1). The antimony content, which was found to be between 40 and 46 mg g(-1), is actually of greater concern, as antimony is known to be potentially toxic already at very low concentrations, although there is no legislation yet for this element.

  11. Antimony leaching in plastics from waste electrical and electronic equipment (WEEE) with various acids and gamma irradiation.

    PubMed

    Tostar, Sandra; Stenvall, Erik; Boldizar, Antal; Foreman, Mark R St J

    2013-06-01

    There has been a recent interest in antimony since the availability in readily mined areas is decreasing compared to the amounts used. It is important in many applications such as flame retardants and in the production of polyester, which can trigger an investigation of the leachability of antimony from plastics using different acids. In this paper, different types of acids are tested for their ability to leach antimony from a discarded computer housing, made of poly(acrylonitrile butadiene styrene), which is a common plastic type used in electrical and electronic equipment. The acid solutions included sodium hydrogen tartrate (0.5M) dissolved in either dimethyl sulfoxide or water (at ca. 23°C and heated to ca. 105°C). The metal content after leaching was determined by inductively coupled plasma optical emission spectroscopy. The most efficient leaching medium was the heated solution of sodium hydrogen tartrate in dimethyl sulfoxide, which leached almost half of the antimony from the poly(acrylonitrile butadiene styrene). Gamma irradiation, which is proposed to improve the mechanical properties in plastics, was used here to investigate the influence of antimony leaching ability. No significant change in the amount of leached antimony could be observed.

  12. Lithium diffusivity in antimony-based intermetallic and FeSb-TiC composite anodes as measured by GITT.

    PubMed

    Allcorn, Eric; Kim, Sang Ok; Manthiram, Arumugam

    2015-11-21

    The diffusion coefficient of lithium is an important parameter in determining the rate capability of an electrode and its ability to deliver high power output. Galvanostatic intermittent titration technique (GITT) is a quick electrochemical method to determine diffusion coefficients in electrode materials and is applied here to antimony-based anodes for lithium-ion batteries. Like other alloy anodes, antimony suffers from large volume change and a short cycle life, so GITT is also applied to determine the effects on lithium diffusivity of antimony intermetallics and composite electrodes designed to mitigate these issues. Pure antimony is measured to have a diffusion coefficient of 4.0 × 10(-9) cm(2) s(-1), in agreement with previously measured values. The intermetallics NiSb, FeSb, and FeSb2 all demonstrate diffusivity values within an order of magnitude of antimony, while Cu2Sb shows roughly an order of magnitude improvement due to the persistence of the Cu2Sb phase during cycling. The composite electrode FeSb-TiC is shown to offer significant enhancement of the diffusion coefficient positively correlated with higher concentrations of TiC in the composite up to a maximum value of 1.9 × 10(-7) cm(2) s(-1) at 60 wt% TiC, nearly two full orders of magnitude greater than that of pure antimony.

  13. Downregulation of mitogen-activated protein kinase 1 of Leishmania donovani field isolates is associated with antimony resistance.

    PubMed

    Ashutosh; Garg, Mansi; Sundar, Shyam; Duncan, Robert; Nakhasi, Hira L; Goyal, Neena

    2012-01-01

    Emergence of resistance to pentavalent antimonials has become a severe obstacle in the treatment of visceral leishmaniasis (VL) on the Indian subcontinent. The mechanisms operating in laboratory-generated strains are somewhat known, but the determinants of clinical antimony resistance are not well understood. By utilizing a DNA microarray expression profiling approach, we identified a gene encoding mitogen-activated protein kinase 1 (MAPK1) for the kinetoplast protozoan Leishmania donovani (LdMAPK1) that was consistently downregulated in antimony-resistant field isolates. The expression level of the gene was validated by real-time PCR. Furthermore, decreased expression of LdMAPK1 was also confirmed at the protein level in resistant isolates. Primary structure analysis of LdMAPK1 revealed the presence of all of the characteristic features of MAPK1. When expressed in Escherichia coli, the recombinant enzyme showed kinase activity with myelin basic protein as the substrate and was inhibited by staurosporine. Interestingly, overexpression of this gene in a drug-sensitive laboratory strain and a resistant field isolate resulted in increased the sensitivity of the transfectants to potassium antimony tartrate, suggesting that it has a role in antimony resistance. Our results demonstrate that downregulation of LdMAPK1 may be in part correlated with antimony drug resistance in Indian VL isolates.

  14. Overexpression of ubiquitin and amino acid permease genes in association with antimony resistance in Leishmania tropica field isolates.

    PubMed

    Kazemi-Rad, Elham; Mohebali, Mehdi; Khadem-Erfan, Mohammad Bagher; Hajjaran, Homa; Hadighi, Ramtin; Khamesipour, Ali; Rezaie, Sassan; Saffari, Mojtaba; Raoofian, Reza; Heidari, Mansour

    2013-08-01

    The mainstay therapy against leishmaniasis is still pentavalent antimonial drugs; however, the rate of antimony resistance is increasing in endemic regions such as Iran. Understanding the molecular basis of resistance to antimonials could be helpful to improve treatment strategies. This study aimed to recognize genes involved in antimony resistance of Leishmania tropica field isolates. Sensitive and resistant L. tropica parasites were isolated from anthroponotic cutaneous leishmaniasis patients and drug susceptibility of parasites to meglumine antimoniate (Glucantime®) was confirmed using in vitro assay. Then, complementary DNA-amplified fragment length polymorphism (cDNA-AFLP) and real-time reverse transcriptase-PCR (RT-PCR) approaches were utilized on mRNAs from resistant and sensitive L. tropica isolates. We identified 2 known genes, ubiquitin implicated in protein degradation and amino acid permease (AAP3) involved in arginine uptake. Also, we identified 1 gene encoding hypothetical protein. Real-time RT-PCR revealed a significant upregulation of ubiquitin (2.54-fold), and AAP3 (2.86-fold) (P<0.05) in a resistant isolate compared to a sensitive one. Our results suggest that overexpression of ubiquitin and AAP3 could potentially implicated in natural antimony resistance.

  15. Metal-induced cyclization of thiosemicarbazones derived from beta-keto amides and beta-keto esters: open-chain and cyclized ligands in zinc(II) complexes.

    PubMed

    Casas, José S; Castaño, María V; Castellano, Eduardo E; Ellena, Javier; García-Tasende, María S; Gato, Angeles; Sánchez, Agustín; Sanjuán, Luisa M; Sordo, José

    2002-03-25

    The reactions of Zn(OAc)(2) with acetoacetanilide, methyl acetoacetate, o-acetoacetanisidide, and ethyl 2-methylacetoacetate thiosemicarbazones (HTSC(1), HTSC(2), HTSC(3), and HTSC(4), respectively) were explored in methanol. With HTSC(1), HTSC(2), and HTSC(3), following isolation of the corresponding zinc(II) thiosemicarbazonates [Zn(TSC(x))(2)] (x = 1, 2, 3), the mother liquors afforded pyrazolonate complexes [ZnL(1)(2)(H(2)O)] (HL(1) = 2,5-dihydro-3-methyl-5-oxo-1H-pyrazole-1-carbothioamide) that had been formed by cyclization of the corresponding TSC(-). The reaction of HTSC(4) with zinc(II) acetate gave only the pyrazolonate complex [ZnL(2)(2)(H(2)O)] (HL(2) = 2,5-dihydro-3,4-dimethyl-5-oxo-1H-pyrazole-1-carbothioamide). All compounds were studied by IR and NMR spectroscopy, and HTSC(3), [Zn(TSC(3))(2)] x DMSO, [ZnL(1)(2)(H(2)O)] x 2DMSO, and [ZnL(2)(2)(H(2)O)] x 2DMSO were also studied by X-ray diffractometry, giving a thorough picture of the cyclization process. In preliminary tests of the effects of HL(1) and [ZnL(1)(2)(H(2)O)] on rat paw inflammatory edema induced by carrageenan, HL(1) showed antiinflammatory activity.

  16. Partial conversion of thioamide into nitrile in a copper(II) complex of 2,6-diacetylpyridine bis(thiosemicarbazone), a drug prototype for Alzheimer's disease.

    PubMed

    Vieira, Rafael P; Thompson, John R; Beraldo, Heloisa; Storr, Tim

    2015-06-01

    This work reports the crystal structure of [(Z)-2-((E)-1-{6-[1-({[amino(sulfanidyl-κS)methylidene]amino}imino-κN)ethyl]pyridin-2-yl-κN}ethylidene)-1-cyanohydrazinido-κN(1)]copper(II), [Cu(C11H11N7S)], the first description of a copper(II) complex of 2,6-diacetylpyridine bis(thiosemicarbazone) showing partial conversion of a thioamide group to a nitrile group. The asymmetric ligand coordinates to the metal centre in an N,N',N'',S-tetradentate manner via the pyridine N atom, an imine N atom, the hydrazinide N atom and the sulfanidyl S atom, displaying a square-planar geometry. Ligand coordination results in two five-membered chelate rings and one six-membered chelate ring, and in crystal packing based on N-H···N hydrogen bonds of the cyanohydrazinide and hydrazinecarbothioamidate arms of the ligand. The correlation between the partial conversion upon metal complexation, H2S release and possible effects on the activity of bis(thiosemicarbazone)s as drug prototypes for Alzheimer's disease is also discussed.

  17. Evaluation of anti-inflammatory effect of derivative (E)-N-(4-bromophenyl)-2-(thiophen-2-ylmethylene)-thiosemicarbazone.

    PubMed

    de Oliveira, Jamerson Ferreira; Nonato, Fabiana Regina; Zafred, Rafael Rosolen Teixeira; Leite, Nayara Maria Siqueira; Ruiz, Ana Lúcia Tasca Gois; de Carvalho, João Ernesto; da Silva, Anekécia Lauro; de Moura, Ricardo Olímpio; Alves de Lima, Maria do Carmo

    2016-05-01

    The present study aimed to further investigate the anti-inflammatory activity of (E)-N-(4-bromophenyl)-2-(thiophen-2-ylmethylene)-thiosemicarbazone (BTTSC) as well as its antinociceptive effects. The anti-inflammatory activity was assessed using the model of ear edema induced by croton oil-induced and also evaluated in models of paw edema carrageenan-induced and by compound 48/80. Evaluation of the antinociceptive effect was performed through formalin test. In the nociception test induced by formalin the BTTSC showed activity in both phases of the pain, highlighting inflammatory pain, where it was able to reduce the time to paw lick 62.3, 84.30 and 100% at doses of 30, 100 and 300mgkg(-1). The anti-inflammatory activity was performed ear edema induced by croton oil, where none of the doses tested was capable of significantly regress edema. The paw edema carrageenan-induced showed activity compound, where the edema was reduced by 81.9 and 83.2% in the first two times of the experiment at the highest dose used. The paw edema assay induced by compound 48/80, showed that BTTSC after 15min of the inoculum phlogistic agent showed significant reduction of edema with values of 56.53% at a dose of 30mgkg(-1). Our results suggesting this compound exerts its antinociception effects connected with peripheral mechanisms. Furthermore, the compound was able to act in two phases of inflammation carrageenan-induced, highlighting the initial phase. This suggests an action on the early mediators of inflammation. The paw edema assay induced by compound 48/80 confirmed our hypothesis indicating action of the compound via histamine.

  18. Characterization of the anticancer effects of S115, a novel heteroaromatic thiosemicarbazone compound, in vitro and in vivo

    PubMed Central

    Liu, Min-yu; Xiao, Lin; Dong, Yu-qiong; Liu, Ying; Cai, Li; Xiong, Wei-xia; Yao, Yu-long; Yin, Ming; Liu, Quan-hai

    2014-01-01

    Aim: To investigate the anticancer effects of S115, a novel heteroaromatic thiosemicarbazone compound in vitro and in vivo. Methods: The anti-proliferative action of S115 was analyzed in 12 human and mouse cancer cell lines using MTT assay. Autograft and xenograft cancer models were made by subcutaneous inoculation of cancer cells into mice or nude mice. The mice were orally treated with S115 (2, 8, 32 mg·kg−1·d−1) for 7 d, and the tumor size was measured every 3 d. Cell apoptosis and cell cycle distribution were examined using flow cytometry, gene expression profile analyses, Western blots and RT-PCR. Results: The IC50 values of S115 against 12 human and mouse cancer cell lines ranged from 0.3 to 6.6 μmol/L. The tumor growth inhibition rate caused by oral administration of S115 (32 mg·kg−1·d−1) were 89.7%, 81.7%, 78.4% and 77.8%, respectively, in mouse model of B16 melanoma, mouse model of Colon26 colon cancer, nude mouse model of A549 lung cancer and nude mouse model of SK-OV-3 ovarian cancer. Furthermore, oral administration of S115 (7.5 mg·kg−1·d−1) synergistically enhanced the anticancer effects of cyclophosphamide, cisplatin, or 5-fluorouracil in mouse model of S180 sarcoma. Treatment of A549 human lung cancer cells with S115 (1.5 μmol/L) induced G0/G1 cell cycle arrest, and increased apoptosis. Furthermore, S115 downregulated the level of ubiquitin, and upregulated the level of Tob2 in A549 cells. Conclusion: S115 exerts anticancer effects against a variety of cancer cells in vitro and in grafted cancer models by inducing apoptosis, downregulating ubiquitin and upregulating Tob2. PMID:25220642

  19. A Species-Specific Approach to the Use of Non-Antimony Treatments for Cutaneous Leishmaniasis

    PubMed Central

    Ramanathan, Roshan; Talaat, Kawsar R.; Fedorko, Daniel P.; Mahanty, Siddhartha; Nash, Theodore E.

    2011-01-01

    We used a species-specific approach to treat 10 patients with cutaneous leishmaniasis diagnosed using polymerase chain reaction. Non-antimony treatments (oral miltefosine, ketoconazole, and liposomal amphotericin B) were chosen as an alternative to pentavalent antimony drugs based on likely or proven drug efficacy against the infecting species. Leishmania Viannia panamensis was diagnosed in three patients and treated successfully with oral ketoconazole. Miltefosine treatment cured two patients with L. infantum chagasi. A wide variety of Leishmania responded to liposomal amphotericin B administered for 5–7 days. Three patients with L. V. braziliensis, one patient with L. tropica, and two patients with L. infantum chagasi were treated successfully. One person with L. V. braziliensis healed slowly because of a resistant bacterial superinfection, and a second patient with L. infantum chagasi relapsed and was retreated with miltefosine. These drugs were reasonably well-tolerated. In this limited case series, alternative non-antimony–based regimens were convenient, safe, and effective. PMID:21212212

  20. Thermal stability and spectroscopic properties of Er 3+-doped antimony-borosilicate glasses

    NASA Astrophysics Data System (ADS)

    Qian, Q.; Zhao, C.; Yang, G. F.; Yang, Z. M.; Zhang, Q. Y.; Jiang, Z. H.

    2008-11-01

    This paper reports on the optical spectroscopic properties and thermal stability of Er 3+-doped antimony-borosilicate glasses for developing 1.5 μm optical amplifiers. Upon excitation at 980 nm laser diode, an intense 1.5 μm infrared fluorescence has been observed with the maximum full width at half maximum (FWHM) of 90 nm for Er 3+-doped antimony-borosilicate glasses. The emission cross-section and the lifetime of the 4I13/2 level of Er 3+ ions are 6.3 × 10 -21 cm 2 and 0.30 ms, respectively. It is noted that the product of the emission cross-section and FWHM of the glass studied is as great as 567 × 10 -21 cm 2 nm, which is comparable or higher than that of bismuthate and tellurite glasses.

  1. Antimony sulfide thin films prepared by laser assisted chemical bath deposition

    NASA Astrophysics Data System (ADS)

    Shaji, S.; Garcia, L. V.; Loredo, S. L.; Krishnan, B.; Aguilar Martinez, J. A.; Das Roy, T. K.; Avellaneda, D. A.

    2017-01-01

    Antimony sulfide (Sb2S3) thin films were prepared by laser assisted chemical bath deposition (LACBD) technique. These thin films were deposited on glass substrates from a chemical bath containing antimony chloride, acetone and sodium thiosulfate under various conditions of normal chemical bath deposition (CBD) as well as in-situ irradiation of the chemical bath using a continuous laser of 532 nm wavelength. Structure, composition, morphology, optical and electrical properties of the Sb2S3 thin films produced by normal CBD and LACBD were analyzed by X-Ray diffraction (XRD), Raman Spectroscopy, Atomic force microscopy (AFM), X-Ray photoelectron spectroscopy (XPS), UV-vis spectroscopy and Photoconductivity. The results showed that LACBD is an effective synthesis technique to obtain Sb2S3 thin films for optoelectronic applications.

  2. Antimony segregation in stressed SiGe heterostructures grown by molecular beam epitaxy

    SciTech Connect

    Drozdov, M. N.; Novikov, A. V.; Yurasov, D. V.

    2013-11-15

    The effects of the growth temperature, composition, and elastic strains in separate layers on the segregation of antimony are studied experimentally for stressed SiGe structures grown by molecular beam epitaxy. It is established that the growth conditions and parameters of the structures exert an interrelated influence on the segregation of Sb: the degree of the influence of the composition and elastic stresses in the SiGe layers on Sb segregation depends on the growth temperature. It is shown that usage of a method previously proposed by us for the selective doping of silicon structures with consideration for the obtained dependences of Sb segregation on the growth conditions and parameters of the SiGe layers makes it possible to form SiGe structures selectively doped with antimony.

  3. Sandwich heterostructures of antimony trioxide and bismuth trioxide films: Structural, morphological and optical analysis

    NASA Astrophysics Data System (ADS)

    Condurache-Bota, Simona; Praisler, Mirela; Gavrila, Raluca; Tigau, Nicolae

    2017-01-01

    Thin film heterostructures can be advantageous since they either exhibit novel or a combination of the properties of their components. Here we propose sandwich-type of heterostructures made of antimony trioxide and bismuth trioxide thin films, which were deposited on glass substrates by thermal vacuum deposition at three substrate temperatures, 50° Celsius apart. Their morphology and optical properties are studied as compared to the corresponding monolayers. It was found that even small substrate temperature changes strongly influence their morphology, increasing their roughness, while the optical transmittance shows a slight decrease as compared with the individual layers. The corresponding absorption coefficient exhibits intermediate values as compared to the component oxides, while the energy bandgaps for the indirect allowed transitions move towards the Infrared when overlapping the antimony and bismuth trioxides.

  4. Numerical simulation and experimental characterization of the performance evolution of a liquid antimony anode fuel cell

    NASA Astrophysics Data System (ADS)

    Cao, Tianyu; Shi, Yixiang; Wang, Hongjian; Cai, Ningsheng

    2015-06-01

    A solid oxide fuel cell (SOFC) with a liquid antimony anode is fabricated based on a smooth single crystal YSZ electrolyte substrate and a porous Pt cathode. The performance of the liquid antimony anode was tested under "battery mode", with the anode chamber shielded in argon throughout the test and the cathode exposed to air. Polarization curves were taken and a long term constant potential discharging test was carried out afterwards. Taking electrochemical reaction, mass transport and microstructure of the liquid Sb anode into consideration, a one dimensional mathematical model was built and then validated by the polarization curve and the constant potential discharging performance curve obtained during the test. This model analyzes the metallic Sb distribution in the anode during cell operation, explains the cell performance evolution base on the microstructural development of the liquid Sb anode and simulates how the anode microstructure affects the cell performance.

  5. An additive approach to low temperature zero pressure sintering of bismuth antimony telluride thermoelectric materials

    NASA Astrophysics Data System (ADS)

    Catlin, Glenn C.; Tripathi, Rajesh; Nunes, Geoffrey; Lynch, Philip B.; Jones, Howard D.; Schmitt, Devin C.

    2017-03-01

    This paper presents an additive-based approach to the formulation of thermoelectric materials suitable for screen printing. Such printing processes are a likely route to such thermoelectric applications as micro-generators for wireless sensor networks and medical devices, but require the development of materials that can be sintered at ambient pressure and low temperatures. Using a rapid screening process, we identify the eutectic combination of antimony and tellurium as an additive for bismuth-antimony-telluride that enables good thermoelectric performance without a high pressure step. An optimized composite of 15 weight percent Sb7.5Te92.5 in Bi0.5Sb1.5Te3 is scaled up and formulated into a screen-printable paste. Samples fabricated from this paste achieve a thermoelectric figure of merit (ZT) of 0.74 using a maximum processing temperature of 748 K and a total thermal processing budget of 12 K-hours.

  6. Effect of iron plaque on antimony uptake by rice (Oryza sativa L.).

    PubMed

    Cui, Xiao-Dan; Wang, Yu-Jun; Hockmann, Kerstin; Zhou, Dong-Mei

    2015-09-01

    Although iron (Fe) plaque has been shown to significantly affect the uptake of toxic antimony (Sb) by rice, knowledge about the influence of iron plaque on antimony (Sb) (amount, mechanisms, etc) is, however, limited. Here, the effect of Fe plaque on Sb(III) and Sb(V) (nominal oxidation states) uptake by rice (Oryza sativa L.) was investigated using hydroponic experiments and synchrotron-based techniques. The results showed that iron plaque immobilized Sb on the surface of rice roots. Although the binding capacity of iron plaque for Sb(III) was markedly greater than that for Sb(V), significantly more Sb(III) was taken up by roots and transported to shoots. In the presence of Fe plaque, Sb uptake into rice roots was significantly reduced, especially for Sb(III). However, this did not translate into decreasing Sb concentrations in rice shoots and even increased shoot Sb concentrations during high Fe-Sb(III) treatment.

  7. Reaction of Antimony-Uranium Composite Oxide in the Chlorination Treatment of Waste Catalyst - 13521

    SciTech Connect

    Sawada, Kayo; Hirabayashi, Daisuke; Enokida, Youichi

    2013-07-01

    The effect of oxygen gas concentration on the chlorination treatment of antimony-uranium composite oxide catalyst waste was investigated by adding different concentrations of oxygen at 0-6 vol% to its chlorination agent of 0.6 or 6 vol% hydrogen chloride gas at 1173 K. The addition of oxygen tended to prevent the chlorination of antimony in the oxide. When 6 vol% hydrogen chloride gas was used, the addition of oxygen up to 0.1 vol% could convert the uranium contained in the catalyst to U{sub 3}O{sub 8} without any significant decrease in the reaction rate compared to that of the treatment without oxygen. (authors)

  8. Synthesis of Antimony Nanotubes via Facile Template-Free Solvothermal Reactions.

    PubMed

    Li, Ruxue; Wang, Xiaohua; Wang, Xinwei; Zhang, Haoran; Pan, Jingxin; Tang, Jilong; Fang, Dan; Ma, Xiaohui; Li, Yongfeng; Yao, Bin; Fan, Jie; Wei, Zhipeng

    2016-12-01

    Uniform antimony (Sb) nanotubes were successfully synthesized via a facile solvothermal method without the need for any surfactants or templates. The Sb nanotubes are confirmed to be pure rhombohedral phase and have better crystallinity. These nanotubes show middle-hollow and open-ended structures, as well as multi-walled structures with the wall thickness of about 10 nm. Also, they have an average size of the diameter of about 50 nm and the length of about 350 nm. On the basis of the structural and morphological studies, a possible rolling mechanism is proposed to explain the formation of Sb nanotubes. It is expected that uniform Sb nanotubes can further be used in wide applications. Graphical Abstract A possible rolling-formation mechanism is proposed for forming pure rhombhedral phase and high crystallinity antimony nanotubes without any surfactants or templates via a facile solvothermal method.

  9. Synthesis, spectroscopic characterization and antibacterial activity of antimony(III) bis(dialkyldithiocarbamato)alkyldithiocarbonates

    NASA Astrophysics Data System (ADS)

    Chauhan, H. P. S.; Bakshi, Abhilasha; Bhatiya, Sumit

    2011-10-01

    Some mixed sulfur donor ligand complexes of antimony(III) of the general formula [(R 2NCS 2)] 2SbS 2COR' where R = CH 3, C 2H 5 and R' = Me, Et, Pr n, Pr i, Bu n and Bu i have been synthesized by the reaction of antimony(III) bis(dialkyldithiocarbamate) chloride with potassium organodithiocarbonate in an equimolar ratio by stirring at room temperature in benzene/CS 2 mixture. These complexes have been characterized by physicochemical [elemental analysis, melting points and molecular weight determinations] and spectral [UV, IR, Far-IR, NMR ( 1H and 13C), FAB + mass and powder X-ray diffraction] studies. Free ligands and synthesized complexes have also been screened against different bacterial strains and results obtained made it desirable to delineate a comparison between free ligands, standard drug used and synthesized complexes.

  10. Evaluation of Antimony Thioantimonate in Three in Vitro Short-Term Assays.

    DTIC Science & Technology

    1984-12-14

    dimethylsulfoxide [Cl potassium chloride DM dimethylnitrosamine MCA 3-me thylcholanthrene CA chromosome aberrations Sb(SbS 4 antimony thioantimonate TG...control compounds, ethylmethanesulfonate (EMS) lot #AZG and dImethylnitrosamIne were purchased from Eastman Kodak Company and Sigma Chemical Company...ethylmethanesulfonate (EMS) at 248 Lg/ml in the - absence of S9 or dimethylnitrosamine (DMN) at 100 jig/ml in the presence of S9. The cells were treated

  11. The heat capacity of solid antimony telluride Sb2Te3

    NASA Astrophysics Data System (ADS)

    Pashinkin, A. S.; Malkova, A. S.; Mikhailova, M. S.

    2008-05-01

    The literature data on the heat capacity of solid antimony telluride over the range 53 895 K were analyzed. The heat capacity of Sb2Te3 was measured over the range 350 700 K on a DSM-2M calorimeter. The equation for the temperature dependence was suggested. The thermodynamic functions of Sb2Te3 were calculated over the range 298.15 700 K.

  12. Development and characterization of ion selective electrode for the assay of antimony.

    PubMed

    Mostafa, G A E

    2007-03-15

    The construction and general performance characteristics of two novel potentiometric carbon paste electrodes (CPE) responsive to antimony are described. These sensors are based on the use of the ion associate complexes of tetraiodoantimonate (TIA) anion with cetylpyridinium (CP) and triphenyl tetrazolium (TPT) counter cations as ion exchange site in a carbon paste matrix. The two sensors exhibits fast, stable and near-Nernstian for the mono charged TIA anion over the concentration range 1x10(-3) to 10(-6)M at 25 degrees C in the pH range 4-10 with anionic slope of 58.0+/-0.5 and 55.0+/-0.7 per concentration decade for TIA-CP and TIA-TPT, respectively. The lower detection limits are 4 and 5x10(-6)M and response time are 20 and 30s in the same order of both electrodes. Selectivity coefficients for antimony relative to a number of different cations and anions were investigated. There is negligible interference from many inorganic cation and anion except for Hg(2+), Cd(2+), and Bi(3+); however, their effect were eliminated by EDTA. The determination of 1.0-120.0mug/ml of antimony in aqueous solutions shows an average recovery of 99.0 and 97.5% with relative standard deviation of 2.0% for both electrodes at 40mug/ml. The determination of antimony in wastewater and some antibilharzial compounds using the proposed electrodes gave results that compare favorably with those obtained by the atomic absorption spectrometric method. Precipitation titrations involving cetylpyridinium chloride as titrant are monitored with both electrodes with inflection point of 180 and 100mV for TIA-CP and TIA-TPT, respectively.

  13. Bi-antimony capped Keggin polyoxometalate modified with Cu-ligand fragment

    SciTech Connect

    Huang, Jiao; Han, Zhangang; Zhang, Heng; Yu, Haitao; Zhai, Xueliang

    2012-10-15

    Three polyoxometalates consisting of bi-antimony capped Keggin-type clusters: [Cu(mbpy){sub 2}]{sub 2}[PMo{sub 12}O{sub 40}Sb{sub 2}]{center_dot}4H{sub 2}O (1), [Cu(mbpy){sub 2}][PMo{sub 12}O{sub 40}Sb{sub 2}] (2) and {l_brace}Cu(mbpy)[Cu(mbpy){sub 2}]{sub 2}{r_brace}[VMo{sub 8}V{sub 4}O{sub 40}Sb{sub 2}]{center_dot}2H{sub 2}O (3) (mbpy=4,4 Prime -dimethyl-2,2 Prime - dipyridyl in 1 and 2; 5,5 Prime -dimethyl-2,2 Prime -dipyridyl in 3) have been synthesized and characterized by IR, X-ray powder diffraction, TG analysis and electrochemical property. Single-crystal analysis revealed that all of three compounds are built upon bi-antimony capped Keggin-type polyoxoanions and Cu-mbpy cations. In 1-3, two Sb{sup III} centers located at the two opposite of anionic surface adopt fundamentally tetragonal pyramidal coordination geometry. Both compounds 1 and 2 consist of P-centered Keggin structure, while compound 3 presents a V-centered Keggin anion. The Keggin-type anions present different structural features: isolated cluster in 1 and Cu-ligand-supported cluster in 2 and 3. - Graphical abstract: Three hybrid compounds consisting of bi-antimony capped Keggin-type clusters modified with Cu-ligand cations have been synthesized and characterized. Highlights: Black-Right-Pointing-Pointer Three hybrid compounds consisting of bi-antimony capped Keggin-type clusters have been synthesized. Black-Right-Pointing-Pointer Two Sb{sup III} centers located at the two opposite of anionic surface adopt tetragonal pyramidal coordination geometry. Black-Right-Pointing-Pointer The anions present different structural features: isolated and Cu-ligand-supported cluster.

  14. Chemically deposited thin films of sulfides and selenides of antimony and bismuth as solar energy materials

    NASA Astrophysics Data System (ADS)

    Nair, M. T.; Nair, Padmanabhan K.; Garcia, V. M.; Pena, Y.; Arenas, O. L.; Garcia, J. C.; Gomez-Daza, O.

    1997-10-01

    Chemical bath deposition techniques for bismuth sulfide, bismuth selenide, antimony sulfide, and antimony selenide thin films of about 0.20 - 0.25 micrometer thickness are reported. All these materials may be considered as solar absorber films: strong optical absorption edges, with absorption coefficient, (alpha) , greater than 104 cm-1, are located at 1.31 eV for Bi2Se3, 1.33 eV for Bi2S3, 1.8 eV for Sb2S3, and 1.35 eV for Sb2Se3. As deposited, all the films are nearly amorphous. However, well defined crystalline peaks matching bismuthinite (JCPDS 17- 0320), paraguanajuatite (JCPDS 33-0214), and stibnite (JCPDS 6-0474) and antimony selenide (JCPDS 15-0861) for Bi2S3, Bi2Se3, Sb2S3 and Sb2Se3 respectively, are observed when the films are annealed in nitrogen at 300 degrees Celsius. This is accompanied by a substantial modification of the electrical conductivity in the films: from 10-7 (Omega) -1 cm-1 (in as prepared films) to 10 (Omega) -1 cm-1 in the case of bismuth sulfide and selenide films, and enhancement of photosensitivity in the case of antimony sulfide films. The chemical deposition of a CuS/CuxSe film on these Vx- VIy films and subsequent annealing at 300 degrees Celsius for 1 h at 1 torr of nitrogen leads to the formation of p-type films (conductivity of 1 - 100 (Omega) -1 cm-1) of multinary composition. Among these, the formation of Cu3BiS3 (JCPDS 9-0488) and Cu3SbS4 (JCPDS 35- 0581), CuSbS2 (JCPDS 35-0413) have been clearly detected. Solar energy applications of these films are suggested.

  15. Long term improvement in the treatment of canine leishmaniosis using an antimony liposomal formulation.

    PubMed

    Valladares, J E; Riera, C; González-Ensenyat, P; Díez-Cascón, A; Ramos, G; Solano-Gallego, L; Gállego, M; Portús, M; Arboix, M; Alberola, J

    2001-05-09

    Pharmacokinetic and clinical effectiveness of liposome-encapsulated N-methylglucamine antimoniate (LMA) was performed in dogs suffering from experimental leishmaniosis. LMA was compared with N-methylglucamine antimoniate (MGA), the same drug in its free form. Sb plasma concentrations for LMA were always higher than those for MGA. Mean residence time (MRT), half-life time (t(1/2)) and clearance (Cl) showed that Sb was eliminated slower after liposome administration. The high volume of distribution (Vd) obtained with LMA suggests that Sb could achieve therapeutic concentrations in parasite-infected tissues. Average plasma concentration at steady state (Css(ave)) shows that Sb body concentrations after LMA treatment (9.8 mg/kg Sb, each 24h) would be effective in Leishmania infantum canine infection. Comparing LMA with MGA in a 1-year follow-up we observed no relapses for LMA and total protein and gammaglobulin concentrations were within normal range, while for MGA both began to rise 3 months after treatment. Use of antimonial liposomal formulations may restore effectiveness to an existing drug and reduce toxicity.

  16. Separation of Arsenic from the Antimony-Bearing Dust through Selective Oxidation Using CuO

    NASA Astrophysics Data System (ADS)

    Zhong, Da-Peng; Li, Lei; Tan, Cheng

    2017-04-01

    A pyrometallurgical process of selective oxidation roasting of the antimony-bearing dust using CuO is put forward, in which the antimony component is oxidized to Sb2O4 staying in the roasted residue, and arsenic is volatilized in the form of As2O3. The addition of CuO has an active effect on the arsenic volatilization, because structures of some complicated As-Sb phases in the dust are destroyed after the "Sb" component in them is oxidized to Sb2O4, and this part of arsenic might be transformed to As2O3, which continues to volatilize. However, the arsenic volatilization rate decreases with the CuO amount in a certain range, which is attributed to the greater formation of Cu3 (AsO4)2 and Cu3As. Under the conditions of roasting temperature of 673 K (400 °C), roasting time of 100 minutes, CuO amount of 34.54 mass pct, and N2 flow rate of 30 mL/min, 91.50 pct arsenic and only 8.63 pct antimony go into the smoke.

  17. Separation of Arsenic from the Antimony-Bearing Dust through Selective Oxidation Using CuO

    NASA Astrophysics Data System (ADS)

    Zhong, Da-Peng; Li, Lei; Tan, Cheng

    2017-01-01

    A pyrometallurgical process of selective oxidation roasting of the antimony-bearing dust using CuO is put forward, in which the antimony component is oxidized to Sb2O4 staying in the roasted residue, and arsenic is volatilized in the form of As2O3. The addition of CuO has an active effect on the arsenic volatilization, because structures of some complicated As-Sb phases in the dust are destroyed after the "Sb" component in them is oxidized to Sb2O4, and this part of arsenic might be transformed to As2O3, which continues to volatilize. However, the arsenic volatilization rate decreases with the CuO amount in a certain range, which is attributed to the greater formation of Cu3 (AsO4)2 and Cu3As. Under the conditions of roasting temperature of 673 K (400 °C), roasting time of 100 minutes, CuO amount of 34.54 mass pct, and N2 flow rate of 30 mL/min, 91.50 pct arsenic and only 8.63 pct antimony go into the smoke.

  18. Study on Determination of Antimony in Environmental Samples by Neutron Activation Analysis

    NASA Astrophysics Data System (ADS)

    Martins, Tassiane Cristina Gomes; Saiki, Mitiko; Zahn, Guilherme Soares

    2011-08-01

    There is an increasing interest in the determination of antimony in environmental samples since this element is cumulative and potentially toxic at very low concentrations. Moreover, the quantification of antimony presents difficulties due to its low concentrations in the samples and to the interference problem in the analyses. In this study, neutron activation analysis procedure was established in order to obtain reliable results for Sb determination in environmental samples. For this study ten reference materials were analyzed. Aliquots of these materials and synthetic standard of Sb were irradiated at the IEA- R1 nuclear reactor under a thermal neutron flux of about 5×1012 n cm-2 s-1 for 8 or 16 hours. The induced gamma activities of 122Sb and 124Sb were measured using a hyperpure Ge detector. Antimony concentrations were calculated by comparative method and the uncertainties of the results were estimated using statistical counting errors of the sample and standard. Relative errors calculated demonstrated that the accuracy of the results depends on the Sb radioisotope measured and the decay time for counting.

  19. Altering the dewetting characteristics of ultrathin gold and silver films using a sacrificial antimony layer.

    PubMed

    Farzinpour, P; Sundar, A; Gilroy, K D; Eskin, Z E; Hughes, R A; Neretina, S

    2012-12-14

    Solid state dewetting of ultrathin films is the most straightforward means of fabricating substrate-supported noble metal nanostructures. This assembly process is, however, quite inflexible, yielding either densely packed smaller structures or widely spaced larger structures. Here, we demonstrate the utility of introducing a sacrificial antimony layer between the substrate and noble metal overlayer. We observe an agglomeration process which is radically altered by the concurrent sublimation of antimony. In stark contrast with conventional dewetting, where the thickness of the deposited metal film determines the characteristic length scales of the assembly process, it is the thickness of the sacrificial antimony layer which dictates both the nanoparticle size and interparticle spacing. The result is a far more flexible self-assembly process where the nanoparticle size and areal density can be varied widely. Demonstrations show nanoparticle areal densities which are varied over four orders of magnitude assembled from the identical gold layer thickness, where the accompanying changes to nanostructure size see a systematic shift in the wavelength of the localized surface plasmon resonance. As a pliable self-assembly process, it offers the opportunity to tailor the properties of an ensemble of nanostructures to meet the needs of specific applications.

  20. Antimony retention and release from drained and waterlogged shooting range soil under field conditions.

    PubMed

    Hockmann, Kerstin; Tandy, Susan; Lenz, Markus; Reiser, René; Conesa, Héctor M; Keller, Martin; Studer, Björn; Schulin, Rainer

    2015-09-01

    Many soils polluted by antimony (Sb) are subject to fluctuating waterlogging conditions; yet, little is known about how these affect the mobility of this toxic element under field conditions. Here, we compared Sb leaching from a calcareous shooting range soil under drained and waterlogged conditions using four large outdoor lysimeters. After monitoring the leachate samples taken at bi-weekly intervals for >1.5 years under drained conditions, two of the lysimeters were subjected to waterlogging with a water table fluctuating according to natural rainfall water infiltration. Antimony leachate concentrations under drained conditions showed a strong seasonal fluctuation between 110 μg L(-1) in summer and <40 μg L(-1) in winter, which closely correlated with fluctuations in dissolved organic carbon (DOC) concentrations. With the development of anaerobic conditions upon waterlogging, Sb in leachate decreased to 2-5 μg L(-1) Sb and remained stable at this level. Antimony speciation measurements in soil solution indicated that this decrease in Sb(V) concentrations was attributable to the reduction of Sb(V) to Sb(III) and the stronger sorption affinity of the latter to iron (Fe) (hydr)oxide phases. Our results demonstrate the importance of considering seasonal and waterlogging effects in the assessment of the risks from Sb-contaminated sites.

  1. Accumulation of antimony and other potentially toxic elements in plants around a former antimony mine located in the Ribes Valley (Eastern Pyrenees)

    NASA Astrophysics Data System (ADS)

    Bech, Jaume; Corrales, Isabel; Duran, Paola; Roca, Núria; Tume, Pedro; Barceló, Juan; Poschenrieder, Charlotte

    2010-05-01

    Soil contamination by antimony is of increasing environmental concern due to the use of this amphoterous p-block element in many industrial applications such as flame retardant, electronics, alloys, rubber and textile industries. However, little is still known about the response of plants to antimony. Here we report on the accumulation of antimony and other potentially toxic elements (mainly As, Pb and Cu) in plants growing around a former antimony mine in the ribes Valley located in the Eastern Pyrenees (424078E, 4686100N alt. 1145 m.a.s.l) that was operating approximately between the years 1870 to 1960. The ore mineral veins are included in quartz gangue. The main ores were: Sulphides: Stibnite (Sb2S3), Pyrite (FeS2), Sphalerite (ZnS), Arsenopyrite (FeAs), Galenite (PbS), Chalcopyrite (CuFeS2), Tetrahydrite (Cu5Sb2S3). Sulphosals: Boulangerite (5PbS•2Sb2S3), Jamesonite (4PbS•FeS•3Sb2S3), Zinckenite (6PbS•7Sb2S3), Plagionite (5PbS•4Sb2S3), Bournonite PbCu (Sb,As)S3, Pyrargirite (Ag3SbS3). Soil and plant samples were taken at five locations with different levels of Sb, As, and polymetallic contamination. Both pseudototal (aqua regia soluble) and extractable (EDTA) concentrations of metals from sites with low (sites 1 and 2), moderate (site 3 and 4) and high (sites 5 and 6) pollutant burdens were studied. The range of agua regia and EDTA values in mgkg-1 is as follows: Sb 8-2904 and 0.88-44; As: 33-16186 and 3.2-167; Pb: 79-4794 and 49-397; Cu: 66-712 and 48-56 mg•kg-1, respectively). While sites 1 to 4 had alkaline soil pH (7.4-8.7), sites 5 and 6 were acidic with values of 6 and 4.6, respectively. Different herbaceous plant species (Poa annua, Echium vulgare, Sonchus asper, Barbera verna among others) at the low and moderately polluted sites were able to efficiently restrict Sb and As transport to shoots showing average concentration ranges between 5.5 and 23 mg/kg As and 1.21 mg/kg and 4.9 mg/kg Sb. However, at the highly polluted acidic sites (5 and

  2. Preparation of superconductor precursor powders

    DOEpatents

    Bhattacharya, Raghunath

    1998-01-01

    A process for the preparation of a precursor metallic powder composition for use in the subsequent formation of a superconductor. The process comprises the steps of providing an electrodeposition bath comprising an electrolyte medium and a cathode substrate electrode, and providing to the bath one or more soluble salts of one or more respective metals which are capable of exhibiting superconductor properties upon subsequent appropriate treatment. The bath is continually energized to cause the metallic and/or reduced particles formed at the electrode to drop as a powder from the electrode into the bath, and this powder, which is a precursor powder for superconductor production, is recovered from the bath for subsequent treatment. The process permits direct inclusion of all metals in the preparation of the precursor powder, and yields an amorphous product mixed on an atomic scale to thereby impart inherent high reactivity. Superconductors which can be formed from the precursor powder include pellet and powder-in-tube products.

  3. Leishmania panamensis infection and antimonial drugs modulate expression of macrophage drug transporters and metabolizing enzymes: impact on intracellular parasite survival

    PubMed Central

    Gómez, Maria Adelaida; Navas, Adriana; Márquez, Ricardo; Rojas, Laura Jimena; Vargas, Deninson Alejandro; Blanco, Victor Manuel; Koren, Roni; Zilberstein, Dan; Saravia, Nancy Gore

    2014-01-01

    Objectives Treatment failure is multifactorial. Despite the importance of host cell drug transporters and metabolizing enzymes in the accumulation, distribution and metabolism of drugs targeting intracellular pathogens, their impact on the efficacy of antileishmanials is unknown. We examined the contribution of pharmacologically relevant determinants in human macrophages in the antimony-mediated killing of intracellular Leishmania panamensis and its relationship with the outcome of treatment with meglumine antimoniate. Methods Patients with cutaneous leishmaniasis who failed (n = 8) or responded (n = 8) to treatment were recruited. Gene expression profiling of pharmacological determinants in primary macrophages was evaluated by quantitative RT–PCR and correlated to the drug-mediated intracellular parasite killing. Functional validation was conducted through short hairpin RNA gene knockdown. Results Survival of L. panamensis after exposure to antimonials was significantly higher in macrophages from patients who failed treatment. Sixteen macrophage drug-response genes were modulated by infection and exposure to meglumine antimoniate. Correlation analyses of gene expression and intracellular parasite survival revealed the involvement of host cell metallothionein-2A and ABCB6 in the survival of Leishmania during exposure to antimonials. ABCB6 was functionally validated as a transporter of antimonial compounds localized in both the cell and phagolysosomal membranes of macrophages, revealing a novel mechanism of host cell-mediated regulation of intracellular drug exposure and parasite survival within phagocytes. Conclusions These results provide insight into host cell mechanisms regulating the intracellular exposure of Leishmania to antimonials and variations among individuals that impact parasite survival. Understanding of host cell determinants of intracellular pharmacokinetics/pharmacodynamics opens new avenues to improved drug efficacy for intracellular

  4. Nanoscaled hydrated antimony (V) oxide as a new approach to first-line antileishmanial drugs

    PubMed Central

    Franco, Antonia MR; Grafova, Iryna; Soares, Fabiane V; Gentile, Gennaro; Wyrepkowski, Claudia DC; Bolson, Marcos A; Sargentini, Ézio; Carfagna, Cosimo; Leskelä, Markku; Grafov, Andriy

    2016-01-01

    Background Coordination compounds of pentavalent antimony have been, and remain, the first-line drugs in leishmaniasis treatment for >70 years. Molecular forms of Sb (V) complexes are commercialized as sodium stibogluconate (Pentostam®) and meglumine antimoniate (MA) (Glucantime®). Ever-increasing drug resistance in the parasites limits the use of antimonials, due to the low drug concentrations being administered against high parasitic counts. Sb5+ toxicity provokes severe side effects during treatment. To enhance therapeutic potency and to increase Sb (V) concentration within the target cells, we decided to try a new active substance form, a hydrosol of Sb2O5·nH2O nanoparticles (NPs), instead of molecular drugs. Methodology/principal findings Sb2O5·nH2O NPs were synthesized by controlled SbCl5 hydrolysis in a great excess of water. Sb2O5·nH2O phase formation was confirmed by X-ray diffraction. The surface of Sb (V) NPs was treated with ligands with a high affinity for target cell membrane receptors. The mean particle size determined by dynamic light scattering and transmission electron microscopy was ~35–45 nm. In vitro tests demonstrated a 2.5–3 times higher antiparasitic activity of Sb (V) nanohybrid hydrosols, when compared to MA solution. A similar comparison for in vivo treatment of experimental cutaneous leishmaniasis with Sb5+ nanohybrids showed a 1.75–1.85 times more effective decrease in the lesions. Microimages of tissue fragments confirmed the presence of NPs inside the cytoplasm of infected macrophages. Conclusion/significance Sb2O5·nH2O hydrosols are proposed as a new form of treatment for cutaneous leishmaniasis caused by Leishmania amazonensis. The NPs penetrate directly into the affected cells, creating a high local concentration of the drug, a precondition to overcoming the parasite resistance to molecular forms of pentavalent antimonials. The nanohybrids are more effective at a lower dose, when compared to MA, the molecular drug. Our

  5. Nickel(II) Complex of Polyhydroxybenzaldehyde N4-Thiosemicarbazone Exhibits Anti-Inflammatory Activity by Inhibiting NF-κB Transactivation

    PubMed Central

    Loh, Sheng Wei; Looi, Chung Yeng; Hassandarvish, Pouya; Phan, Alicia Yi Ling; Wong, Won Fen; Wang, Hao; Paterson, Ian C.; Ea, Chee Kwee; Mustafa, Mohd Rais; Maah, Mohd Jamil

    2014-01-01

    Background The biological properties of thiosemicarbazone have been widely reported. The incorporation of some transition metals such as Fe, Ni and Cu to thiosemicarbazone complexes is known to enhance its biological effects. In this study, we incorporated nickel(II) ions into thiosemicarbazone with N4-substitution groups H3L (H; H3L1, CH3; H3L2, C6H5; H3L3 and C2H5; H3L4) and examined its potential anti-inflammatory activity. Methodology/Principal Findings Four ligands (1–4) and their respective nickel-containing complexes (5–8) were synthesized and characterized. The compounds synthesized were tested for their effects on NF-κB nuclear translocation, pro-inflammatory cytokines secretion and NF-κB transactivation activity. The active compound was further evaluated on its ability to suppress carrageenan-induced acute inflammation in vivo. A potential binding target of the active compound was also predicted by molecular docking analysis. Conclusions/Significance Among all synthesized compounds tested, we found that complex [Ni(H2L1)(PPh3)]Cl (5) (complex 5), potently inhibited IκBα degradation and NF-κB p65 nuclear translocation in LPS-stimulated RAW264.7 cells as well as TNFα-stimulated HeLa S3 cells. In addition, complex 5 significantly down-regulated LPS- or TNFα-induced transcription of NF-κB target genes, including genes that encode the pro-inflammatory cytokines TNFα, IFNβ and IL6. Luciferase reporter assays confirmed that complex 5 inhibited the transactivation activity of NF-κB. Furthermore, the anti-inflammatory effect of complex 5 was also supported by its suppressive effect on carrageenan-induced paw edema formation in wild type C57BL/6 mice. Interestingly, molecular docking study showed that complex 5 potentially interact with the active site of IKKβ. Taken together, we suggest complex 5 as a novel NF-κB inhibitor with potent anti-inflammatory effects. PMID:24977407

  6. BAC-MP4 predictions of thermochemistry for gas-phase antimony compounds in the Sb-H-C-O-Cl system.

    PubMed

    Skulan, Andrew J; Nielsen, Ida M B; Melius, Carl F; Allendorf, Mark D

    2006-05-04

    Calibrated by both experimental data and high-level coupled-cluster calculations, the BAC-MP4 methodology was applied to 51 SbL(n) (L = H, CH(3), C(2)H(5), Cl, and OH, n = 1-5) molecules, providing calculated heats of formation and associated thermodynamic parameters. These data identify a linear variation in heats of formation with ligand substitution, trends in bond dissociation energies (BDEs) with ligand identity [BDE(Sb-C(2)H(5)) < BDE(Sb-CH(3)) < BDE(Sb-H) < BDE(Sb-Cl) < BDE(Sb-OH)], and a monotonic decrease in BDE upon successive ligand elimination. The linear variation in BDE is consistent with the behavior of other group V elements, in contrast to the characteristic high-low-high trend of adjacent group III (In) and group IV (Sn) elements. Additionally, these data complement those of previous studies of metal-organic species and provide a foundation of thermochemical data that can aid in the selection of CVD precursors and deposition conditions for the growth of antimony-containing materials.

  7. Antimony(III) and bismuth(III) amides containing pendant N-donor groups--a combined experimental and theoretical study.

    PubMed

    Vránová, Iva; Jambor, Roman; Růžička, Aleš; Hoffmann, Alexander; Herres-Pawlis, Sonja; Dostál, Libor

    2015-01-07

    N,N- and N,N,N-chelated antimony(III) and bismuth(III) chlorides L(1-3)MCl2 1-4 [for L(1): M = Sb (1), for L(2): M = Sb (2) and for L(3): M = Sb (3) and Bi (4)], containing ligands L(1-3) derived from the pyrrole ring (where L(1) = C4H3N-2-(CH[double bond, length as m-dash]N-2',6'-iPr2C6H3), L(2) = C4H2N-2,5-(CH2NMe2)2, L(3) = C4H2N-2,5-(CH2NC4H8)2), were prepared by the treatment of lithium precursors with SbCl3 or BiCl3. Molecular structures 1-4 of were described both in solution (NMR spectroscopy) and in the solid state (single-crystal X-ray diffraction analysis). Structures of 1-4 were also subjected to a density functional theory study.

  8. Species-Specific Antimonial Sensitivity in Leishmania Is Driven by Post-Transcriptional Regulation of AQP1

    PubMed Central

    Mandal, Goutam; Mandal, Srotoswati; Sharma, Mansi; Charret, Karen Santos; Papadopoulou, Barbara; Bhattacharjee, Hiranmoy; Mukhopadhyay, Rita

    2015-01-01

    Leishmania is a digenetic protozoan parasite causing leishmaniasis in humans. The different clinical forms of leishmaniasis are caused by more than twenty species of Leishmania that are transmitted by nearly thirty species of phlebotomine sand flies. Pentavalent antimonials (such as Pentostam or Glucantime) are the first line drugs for treating leishmaniasis. Recent studies suggest that pentavalent antimony (Sb(V)) acts as a pro-drug, which is converted to the more active trivalent form (Sb(III)). However, sensitivity to trivalent antimony varies among different Leishmania species. In general, Leishmania species causing cutaneous leishmaniasis (CL) are more sensitive to Sb(III) than the species responsible for visceral leishmaniasis (VL). Leishmania aquaglyceroporin (AQP1) facilitates the adventitious passage of antimonite down a concentration gradient. In this study, we show that Leishmania species causing CL accumulate more antimonite, and therefore exhibit higher sensitivity to antimonials, than the species responsible for VL. This species-specific differential sensitivity to antimonite is directly proportional to the expression levels of AQP1 mRNA. We show that the stability of AQP1 mRNA in different Leishmania species is regulated by their respective 3’-untranslated regions. The differential regulation of AQP1 mRNA explains the distinct antimonial sensitivity of each species. PMID:25714343

  9. Development of an analytical method for antimony speciation in vegetables by HPLC-hydride generation-atomic fluorescence spectrometry.

    PubMed

    Olivares, David; Bravo, Manuel; Feldmann, Jorg; Raab, Andrea; Neaman, Alexander; Quiroz, Waldo

    2012-01-01

    A new method for antimony speciation in terrestrial edible vegetables (spinach, onions, and carrots) was developed using HPLC with hydride generation-atomic fluorescence spectrometry. Mechanical agitation and ultrasound were tested as extraction techniques. Different extraction reagents were evaluated and optimal conditions were determined using experimental design methodology, where EDTA (10 mmol/L, pH 2.5) was selected because this chelate solution produced the highest extraction yield and exhibited the best compatibility with the mobile phase. The results demonstrated that EDTA prevents oxidation of Sb(III) to Sb(V) and maintains the stability of antimony species during the entire analytical process. The LOD and precision (RSD values obtained) for Sb(V), Sb(III), and trimethyl Sb(V) were 0.08, 0.07, and 0.9 microg/L and 5.0, 5.2, and 4.7%, respectively, for a 100 microL sample volume. The application of this method to real samples allowed extraction of 50% of total antimony content from spinach, while antimony extracted from carrots and onion samples ranged between 50 and 60 and 54 and 70%, respectively. Only Sb(V) was detected in three roots (onion and spinach) that represented 60-70% of the total antimony in the extracts.

  10. Thin films of copper antimony sulfide: A photovoltaic absorber material

    SciTech Connect

    Ornelas-Acosta, R.E.; Shaji, S.; Avellaneda, D.; Castillo, G.A.; Das Roy, T.K.; Krishnan, B.

    2015-01-15

    Highlights: • CuSbS{sub 2} thin films were prepared by heating Sb{sub 2}S{sub 3}/Cu layers. • Analyzed the structure, composition, optical, and electrical properties. • PV structures: glass/SnO{sub 2}:F/n-CdS/p-CuSbS{sub 2}/C/Ag were formed at different conditions. • The PV parameters (J{sub sc}, V{sub oc}, and FF) were evaluated from the J–V characteristics. • J{sub sc}: 0.52–3.20 mA/cm{sup 2}, V{sub oc}:187–323 mV, FF: 0.27–0.48 were obtained. - Abstract: In this work, we report preparation and characterization of CuSbS{sub 2} thin films by heating glass/Sb{sub 2}S{sub 3}/Cu layers and their use as absorber material in photovoltaic structures: glass/SnO{sub 2}:F/n-CdS/p-CuSbS{sub 2}/C/Ag. The Sb{sub 2}S{sub 3} thin films of 600 nm were prepared by chemical bath deposition on which copper thin films of 50 nm were thermally evaporated, and the glass/Sb{sub 2}S{sub 3}/Cu multilayers were heated in vacuum at different temperatures. X-ray diffraction analysis showed the formation of orthorhombic CuSbS{sub 2} after heating the precursor layers. Studies on identification and chemical state of the elements were done using X-ray photoelectron spectroscopy. The optical band gap of the CuSbS{sub 2} thin films was 1.55 eV and the thin films were photoconductive. The photovoltaic parameters of the devices using CuSbS{sub 2} as absorber and CdS as window layer were evaluated from the J–V curves, yielding J{sub sc}, V{sub oc}, and FF values in the range of 0.52–3.20 mA/cm{sup 2}, 187–323 mV, and 0.27–0.48, respectively, under illumination of AM1.5 radiation.

  11. Spectral studies on Co(II), Ni(II) and Cu(II) complexes with thiosemicarbazone (L1) and semicarbazone (L2) derived from 2-acetyl furan.

    PubMed

    Chandra, Sulekh; Kumar, Anil

    2007-04-01

    Co(II), Ni(II) and Cu(II) complexes are synthesized with thiosemicarbazone (L1) and semicarbazone (L2) derived from 2-acetyl furan. These complexes are characterized by elemental analysis, molar conductance, magnetic susceptibility measurements, mass, IR, electronic and EPR spectral studies. The molar conductance measurements of the complexes in DMSO correspond to non-electrolytic nature except Ni(L)2(NO3)2, which is 1:2 electrolyte. All the complexes are of high-spin type. On the basis of spectral studies an octahedral geometry may be assigned for Co(II) and Ni(II) complexes except nitrato complexes of Ni(II) which is of tetrahedral geometry, whereas tetragonal geometry for Cu(II) complexes.

  12. Spectral, IR and magnetic studies of Mn(II), Co(II), Ni(II) and Cu(II) complexes with pyrrole-2-carboxyaldehyde thiosemicarbazone (L).

    PubMed

    Chandra, Sulekh; Kumar, Anil

    2007-11-01

    Mn(II), Co(II), Ni(II) and Cu(II) complexes are synthesized with thiosemicarbazone (L) derived from pyrrole-2-carboxyaldehyde. These complexes are characterized by elemental analysis, molar conductance, magnetic susceptibility measurement, mass, IR, electronic and EPR spectral studies. The molar conductance measurement of the complexes in DMSO indicates that the complexes are non-electrolyte except Co(L)2(NO3)2 and Ni(L)2(NO3)2 complexes which are 1:2 electrolyte. All the complexes are of high-spin type. On the basis of spectral studies an octahedral geometry may be assigned for Mn(II), Co(II) and Ni(II) complexes except Co(L)2(NO3)2 and Ni(L)2(NO3)2 which are of tetrahedral geometry. A tetragonal geometry may be suggested for Cu(II) complexes.

  13. Cu(II) Bis(thiosemicarbazone) Radiopharmaceutical Binding to Serum Albumin: Further Definition of Species-Dependence and Associated Substituent Effects

    PubMed Central

    Basken, Nathan E.; Green, Mark A.

    2009-01-01

    Introduction The Cu-PTSM (pyruvaldehyde bis(N4-methylthiosemicarbazonato)copper(II)) and Cu-ATSM (diacetyl bis(N4-methylthiosemicarbazonato)copper(II)) radiopharmaceuticals exhibit strong, species-dependent binding to the IIA site of human serum albumin (HSA), while the related Cu-ETS (ethylglyoxal bis(thiosemicarbazonato)copper(II)) radiopharmaceutical appears to only exhibit non-specific binding to human and animal serum albumins. Methods To further probe the structural basis for the species-dependence of this albumin binding interaction, protein binding of these three radiopharmaceuticals was examined in solutions of albumin and/or serum from a broader array of mammalian species (rat, sheep, donkey, rabbit, cow, pig, dog, baboon, mouse, cat, elephant). We also evaluated the albumin binding of several copper(II) bis(thiosemicarbazone) chelates offering more diverse substitution of the ligand backbone. Results Cu-PTSM and Cu-ATSM exhibit a strong interaction with HSA that is not apparent with the albumins of other species, while the binding of Cu-ETS to albumin is much less species-dependent. The strong interaction of Cu-PTSM with HSA does not appear to simply correlate with variation, relative to the animal albumins, of a single amino acid lining HSA's IIA site. Those agents that selectively interact with HSA share the common feature of only methyl or hydrogen substitution at the carbon atoms of the diimine fragment of the ligand backbone. Conclusions The interspecies variations in albumin binding of Cu-PTSM and Cu-ATSM are not simply explained by unique amino acid substitutions in the IIA binding pocket of the serum albumins. However, the specific affinity for this region of HSA is disrupted when substituents bulkier than a methyl group appear on the imine carbons of the copper bis(thiosemicarbazone) chelate. PMID:19520290

  14. Influence of terminal substitution on structural, DNA, protein binding, anticancer and antibacterial activities of palladium(II) complexes containing 3-methoxy salicylaldehyde-4(N) substituted thiosemicarbazones.

    PubMed

    Kalaivani, P; Prabhakaran, R; Ramachandran, E; Dallemer, F; Paramaguru, G; Renganathan, R; Poornima, P; Vijaya Padma, V; Natarajan, K

    2012-02-28

    The variable chelating behavior of 3-methoxysalicylaldehyde-4(N)-substituted thiosemicarbazones was observed in equimolar reactions with [PdCl(2)(PPh(3))(2)]. The new complexes were characterized by various analytical, spectroscopic techniques (mass, (1)H-NMR, absorption, IR). All the new complexes were structurally characterized by single crystal X-ray diffraction. Crystallographic results showed that the ligands H(2)L(1) and H(2)L(4) are coordinated as binegative tridentate ONS donor ligands in the complexes 1 and 4 by forming six and five member rings. However, the ligands H(2)L(2) and H(2)L(3) bound to palladium in 2 and 3 as uninegative bidentate NS donors by forming a five member chelate ring. From this study, it was found that the substitution on terminal 4(N)-nitrogen may have an influence on the chelating ability of thiosemicarbazone. The presence of hydrogen bonding in 2 and 3 might be responsible for preventing the coordination of phenolic oxygen to the metal ion. The interaction of the complexes with calf-thymus DNA (CT-DNA) has been explored by absorption and emission titration methods. Based on the observations, an electrostatic binding mode of DNA has been proposed. The protein binding studies were monitored by quenching of tryptophan and tyrosine residues in the presence of complexes using Lysozyme as model protein. Antibacterial activity studies of the complexes have been screened against pathogenic bacteria such as Enterococcus faecalis, Staphylococcus aureus, Escherichia coli, Klebsiella pneumonia and Pseudomonas aeruginosa. MIC50 values of the complexes showed that they exhibited significant activity against the pathogens and among them, 3 exhibited higher activity. Further, anticancer activity of the complexes on the lung cancer cell line A549 has also been studied.

  15. Synthesis, structures, spectroscopy and antimicrobial properties of complexes of copper(II) with salicylaldehyde N-substituted thiosemicarbazones and 2,2'-bipyridine or 1,10-phenanthroline.

    PubMed

    Lobana, Tarlok S; Indoria, Shikha; Jassal, Amanpreet Kaur; Kaur, Harpreet; Arora, Daljit S; Jasinski, Jerry P

    2014-04-09

    Among the biometals (Cu, Co, Ni-cofactors in many enzymes), copper derivatives of O, N, S-donor salicylaldehyde thiosemicarbazones have received considerable attention owing to their potential biological applications. Eight new complexes of salicylaldehyde-N-substituted thiosemicarbazones [5-MeO-2-HO-C₆H₄-C(2)(H)N(3)-N(2)H-C(1)(S)-N(1)HR; R = Me, H2L(1); Et, H₂L(1), Ph, H₂L(3), H, H₂L(4)] with copper(II), namely, [Cu(κ(3)-O,N,S-L)( κ(2)-N,N-L')] {(L)(2-) = (L(1))(2-), L' = bipy, 1, phen, 2; (L)(2-) = (L(2))(2-), L' = bipy, 3, phen, 4; (L)(2-) = (L(3))(2-), L' = bipy, 5, phen, 6; (L)(2-) = (L(4))(2-), L' = bipy, 7, phen, 8} have been isolated. Complexes have slightly distorted square pyramidal geometry around the metal center (τ parameter = 0.243-0.357) and display weak to intense fluorescence in the region, 375-475 nm. These copper complexes have shown significant growth inhibitory activity (antimicrobial activity) against Staphylococcus aureus (MTCC740), methicillin resistant Staphylococcus aureus (MRSA), Klebsiella pneumoniae 1 (MTCC109), Shigella flexneri (MTCC1457), Pseudomonas aeruginosa (MTCC741) and Candida albicans (MTCC227). The activity against MRSA is an interesting observation as the commercially available gentamycin is found to be inactive against this bacterial strain. Specifically complex 5 formed by 5-methoxysalicylaldehyde-N-phenylthiosemicatbazone has shown novel antimicrobial activity against various bacteria and yeast investigated.

  16. Pharmacokinetics of meglumine antimoniate after administration of a multiple dose in dogs experimentally infected with Leishmania infantum.

    PubMed

    Valladares, J E; Riera, C; Alberola, J; Gállego, M; Portús, M; Cristòfol, C; Franquelo, C; Arboix, M

    1998-02-15

    Pharmacokinetics of meglumine antimoniate in dogs with experimentally induced leishmaniosis has been investigated. After infection, dogs received a dose of 75 mg kg-1 of meglumine antimoniate twice daily by subcutaneous injection for 10 days. Blood samples were collected throughout the treatment. No statistical differences were found in the kinetic behaviour of the drug administered as a single dose to healthy dogs and that administered as a multiple dose to infected animals. However, peak plasma concentrations (Cmax) of 30.8 +/- 12.8 micrograms ml-1 found after this dosage regimen were higher than those observed after the single dose administration of 100 mg kg-1 24 h-1. Furthermore, sustained antimony concentrations of 1.14 +/- 0.52 micrograms Sb ml-1 were detected throughout the treatment. No signs of toxicity were found in the animals treated indicating that this regimen would be very appropriate to treat canine leishmaniosis.

  17. Analytical application of nano-sized titanium dioxide for the determination of trace inorganic antimony in natural waters.

    PubMed

    Hagarová, Ingrid; Matúš, Peter; Bujdoš, Marek; Kubová, Jana

    2012-03-01

    In this work, solid phase extraction (SPE) using nano-sized TiO2 as a solid sorbent was used for separation/preconcentration of total inorganic antimony (iSb) before its determination by electrothermal atomic absorption spectrometry (ETAAS). After adsorption of iSb onto nano-sized TiO2, direct TiO2-slurry sampling was used for sample injection into a graphite tube. The conditions for the reliable slurry sampling together with careful control of the temperature program for the slurry solutions were worked out. Extraction conditions for both inorganic antimony species (Sb(III) and Sb(V)) and interference studies of coexisting ions were studied in detail. The accuracy of the optimized method was checked by the certified reference material (CRM) for trace elements in lake water TMDA-61. Finally, the optimized method was used for the determination of trace inorganic antimony in synthetic and natural waters.

  18. Penicillamine as an adjuvant to antimonial therapy of schistosomiasis: effect on liver function tests in rabbits and on antischistosomal activity*

    PubMed Central

    Khayyal, M. T.; Saleh, S.; El Masri, A. M.

    1973-01-01

    Earlier work has shown that penicillamine reduces the acute toxicity of antimonyl potassium tartrate (APT) as well as the abnormal ECG changes it induces. In the present study, the possible protective effect of penicillamine on the hepatic toxicity of APT was investigated. Tests of liver function showed changes in the level of serum aspartate and alanine aminotransferase and of alkaline phosphatase, and in the beta-/alpha-lipoprotein ratio, in response to antimony treatment. The changes were significantly reduced by penicillamine, though the effect depended on the dose. Penicillamine was found to give the best overall protection without affecting the antischistosomal efficacy of the antimonial when a 1:2 APT/penicillamine ratio was used. The findings provide further evidence of the potential usefulness of penicillamine in the antimonial treatment of schistosomiasis. PMID:4543547

  19. Precursor decay in several aluminas

    NASA Astrophysics Data System (ADS)

    Murray, N. H.; Bourne, N. K.; Rosenberg, Z.

    1996-05-01

    Plate impact experiments were performed on three ceramics with alumina content varying from 88 to 99.9% using a 50 mm single stage gas gun. Tiles of ceramic with thicknesses varying from 2 to 12 mm were impacted above their Hugoniot Elastic Limits (HELs) and the rate dependent strength was investigated by monitoring the variation in amplitude of the elastic precursor with propagation distance. Stress levels in the target were recorded using manganin stress transducers and a 1 GS s-1 storage oscilloscope. All grades of alumina were found to exhibit some elastic precursor decay indicating strain rate sensitivity.

  20. Field-portable-XRF reveals the ubiquity of antimony in plastic consumer products.

    PubMed

    Turner, Andrew; Filella, Montserrat

    2017-02-09

    Very little systematic information exists on the occurrence and concentrations of antimony (Sb) in consumer products. In this study, a Niton XL3t field-portable-X-ray fluorescence (FP-XRF) spectrometer was deployed in situ and in the laboratory to provide quantitative information on Sb dissipated in plastic items and fixtures (including rubber, textile and foamed materials) from the domestic, school, vehicular and office settings. The metalloid was detected in 18% of over 800 measurements performed, with concentrations ranging from about 60 to 60,000μgg(-1). The highest concentrations were encountered in white, electronic casings and in association with similar concentrations of Br, consistent with the use of antimony oxides (e.g. Sb2O3) as synergistic flame retardants. Concentrations above 1000μgg(-1), and with or without Br, were also encountered in paints, piping and hosing, adhesives, whiteboards, Christmas decorations, Lego blocks, document carriers, garden furniture, upholstered products and interior panels of private motor vehicles. Lower concentrations of Sb were encountered in a wide variety of items but its presence (without Br) in food tray packaging, single-use drinks bottles, straws and small toys were of greatest concern from a human health perspective. While the latter observations are consistent with the use of antimony compounds as catalysts in the production of polyethylene terephthalate, co-association of Sb and Br in many products not requiring flame retardancy suggests that electronic casings are widely recycled. Further research is required into the mobility of Sb when dissipated in new, recycled and aged polymeric materials.

  1. Silver and Nitrate Oppositely Modulate Antimony Susceptibility through Aquaglyceroporin 1 in Leishmania (Viannia) Species

    PubMed Central

    Andrade, Juvana M.; Baba, Elio H.; Machado-de-Avila, Ricardo A.; Chavez-Olortegui, Carlos; Demicheli, Cynthia P.; Frézard, Frédéric

    2016-01-01

    Antimony (Sb) resistance in leishmaniasis chemotherapy has become one of the major challenges to the control of this spreading worldwide public health problem. Since the plasma membrane pore-forming protein aquaglyceroporin 1 (AQP1) is the major route of Sb uptake in Leishmania, functional studies are relevant to characterize drug transport pathways in the parasite. We generated AQP1-overexpressing Leishmania guyanensis and L. braziliensis mutants and investigated their susceptibility to the trivalent form of Sb (SbIII) in the presence of silver and nitrate salts. Both AQP1-overexpressing lines presented 3- to 4-fold increased AQP1 expression levels compared with those of their untransfected counterparts, leading to an increased SbIII susceptibility of about 2-fold. Competition assays using silver nitrate, silver sulfadiazine, or silver acetate prior to SbIII exposure increased parasite growth, especially in AQP1-overexpressing mutants. Surprisingly, SbIII-sodium nitrate or SbIII-potassium nitrate combinations showed significantly enhanced antileishmanial activities compared to those of SbIII alone, especially against AQP1-overexpressing mutants, suggesting a putative nitrate-dependent modulation of AQP1 activity. The intracellular level of antimony quantified by graphite furnace atomic absorption spectrometry showed that the concomitant exposure to SbIII and nitrate favors antimony accumulation in the parasite, increasing the toxicity of the drug and culminating with parasite death. This is the first report showing evidence of AQP1-mediated SbIII susceptibility modulation by silver in Leishmania and suggests the potential antileishmanial activity of the combination of nitrate salts and SbIII. PMID:27161624

  2. Lithium-antimony-lead liquid metal battery for grid-level energy storage

    NASA Astrophysics Data System (ADS)

    Wang, Kangli; Jiang, Kai; Chung, Brice; Ouchi, Takanari; Burke, Paul J.; Boysen, Dane A.; Bradwell, David J.; Kim, Hojong; Muecke, Ulrich; Sadoway, Donald R.

    2014-10-01

    The ability to store energy on the electric grid would greatly improve its efficiency and reliability while enabling the integration of intermittent renewable energy technologies (such as wind and solar) into baseload supply. Batteries have long been considered strong candidate solutions owing to their small spatial footprint, mechanical simplicity and flexibility in siting. However, the barrier to widespread adoption of batteries is their high cost. Here we describe a lithium-antimony-lead liquid metal battery that potentially meets the performance specifications for stationary energy storage applications. This Li||Sb-Pb battery comprises a liquid lithium negative electrode, a molten salt electrolyte, and a liquid antimony-lead alloy positive electrode, which self-segregate by density into three distinct layers owing to the immiscibility of the contiguous salt and metal phases. The all-liquid construction confers the advantages of higher current density, longer cycle life and simpler manufacturing of large-scale storage systems (because no membranes or separators are involved) relative to those of conventional batteries. At charge-discharge current densities of 275 milliamperes per square centimetre, the cells cycled at 450 degrees Celsius with 98 per cent Coulombic efficiency and 73 per cent round-trip energy efficiency. To provide evidence of their high power capability, the cells were discharged and charged at current densities as high as 1,000 milliamperes per square centimetre. Measured capacity loss after operation for 1,800 hours (more than 450 charge-discharge cycles at 100 per cent depth of discharge) projects retention of over 85 per cent of initial capacity after ten years of daily cycling. Our results demonstrate that alloying a high-melting-point, high-voltage metal (antimony) with a low-melting-point, low-cost metal (lead) advantageously decreases the operating temperature while maintaining a high cell voltage. Apart from the fact that this finding

  3. Antimony film sensor for sensitive rare earth metal analysis in environmental samples.

    PubMed

    Makombe, Martin; van der Horst, Charlton; Silwana, Bongiwe; Iwuoha, Emmanuel; Somerset, Vernon

    2016-07-02

    A sensor for the adsorptive stripping voltammetric determination of rare earth elements has been developed. The electrochemical procedure is based on the oxidation of the rare earth elements complexed with alizarin complexone at a glassy carbon electrode that was in situ modified with an antimony film, during an anodic scan from -0.2 V to 1.1 V (vs. Ag/AgCl) and deposition potential of -0.1 V (vs. Ag/AgCl). The factors influencing the adsorptive stripping capability were optimised, including the complexing agent concentration, plating concentration of antimony and deposition time. The detection of rare earth elements (La, Ce and Pr) were realised in 0.08 M sodium acetate (pH = 5.8) solution as supporting electrolyte, with 2 × 10(-6) M alizarin complexone and 1.0 mg L(-1) antimony solution. Under the optimised conditions, a deposition time of 360 s was obtained and a linear response was observed between 1 and 25 µg L(-1). The reproducibility of the voltammetric measurements was found to be within 5.0% RSD for 12 replicate measurements of cerium(III) concentration of 5 µg L(-1) using the same electrode surface. The detection limits obtained using stripping analysis was 0.06, 0.42 and 0.71 μg L(-1) for Ce(III), La(III) and Pr(III), respectively. The developed sensor has been successfully applied for the determination of cerium, lanthanum and praseodymium in municipal tap water samples.

  4. Silver and Nitrate Oppositely Modulate Antimony Susceptibility through Aquaglyceroporin 1 in Leishmania (Viannia) Species.

    PubMed

    Andrade, Juvana M; Baba, Elio H; Machado-de-Avila, Ricardo A; Chavez-Olortegui, Carlos; Demicheli, Cynthia P; Frézard, Frédéric; Monte-Neto, Rubens L; Murta, Silvane M F

    2016-08-01

    Antimony (Sb) resistance in leishmaniasis chemotherapy has become one of the major challenges to the control of this spreading worldwide public health problem. Since the plasma membrane pore-forming protein aquaglyceroporin 1 (AQP1) is the major route of Sb uptake in Leishmania, functional studies are relevant to characterize drug transport pathways in the parasite. We generated AQP1-overexpressing Leishmania guyanensis and L. braziliensis mutants and investigated their susceptibility to the trivalent form of Sb (Sb(III)) in the presence of silver and nitrate salts. Both AQP1-overexpressing lines presented 3- to 4-fold increased AQP1 expression levels compared with those of their untransfected counterparts, leading to an increased Sb(III) susceptibility of about 2-fold. Competition assays using silver nitrate, silver sulfadiazine, or silver acetate prior to Sb(III) exposure increased parasite growth, especially in AQP1-overexpressing mutants. Surprisingly, Sb(III)-sodium nitrate or Sb(III)-potassium nitrate combinations showed significantly enhanced antileishmanial activities compared to those of Sb(III) alone, especially against AQP1-overexpressing mutants, suggesting a putative nitrate-dependent modulation of AQP1 activity. The intracellular level of antimony quantified by graphite furnace atomic absorption spectrometry showed that the concomitant exposure to Sb(III) and nitrate favors antimony accumulation in the parasite, increasing the toxicity of the drug and culminating with parasite death. This is the first report showing evidence of AQP1-mediated Sb(III) susceptibility modulation by silver in Leishmania and suggests the potential antileishmanial activity of the combination of nitrate salts and Sb(III).

  5. Tissue distribution of trivalent antimony in mice infected with Schistosoma mansoni

    PubMed Central

    Molokhia, M. M.; Smith, H.

    1969-01-01

    The work described in this paper is designed to use the very high analytical sensitivity of neutron-activation analysis. The antimony content of individual organs and pieces of organs have been analysed as part of an investigation of the chemotherapy of schistosomiasis. The results illustrate the great, and as yet relatively unapplied, value of this technique in dealing with the investigation of trace elements in biological systems. Values such as those given form firm bases on which further studies can be built and show that the single animal has the same metabolic reactions as those deduced from bulked samples, but of course with individual variations. PMID:5306316

  6. Pharmacokinetics of experimental pentavalent antimony after intramuscular administration in adult volunteers*

    PubMed Central

    Vásquez, Laura; Scorza Dagert, José V.; Scorza, José V.; Vicuña-Fernández, Nelson; de Peña, Yaneira Petit; López, Sabrina; Bendezú, Herminia; Rojas, Elina; Vásquez, Libia; Pérez, Belén

    2006-01-01

    Background: Pentavalent antimony (SbV) has demonstrated therapeuticeffectiveness against clinical manifestations of leishmaniasis, an infection caused by Leishmania, a genus of flagellate protozoa comprising parasites of worldwide distribution. Approximately 1.8 million new cases are reported annually. Objective: The aim of this study was to assess the pharmacokinetics of the investigational generic SbV, Ulamina (pentachloride of antimony + N-methylglucamine), in healthy adult volunteers. Methods: In this study, SbV was administered IM as a single 5-mg/kg dose.Blood samples were collected at 0.25, 0.75, 1, 2, 4, 8, 12, and 24 hours after administration; urine samples were collected at 6-hour intervals during the 24-hour postadministration period. Determination of trivalent antimony, SbV, and total antimony concentrations in blood and urine samples was carried out using atomic absorption spectrometry. Clinical history was reviewed and the subjects were monitored before and after administration of SbV using physical examination, weight, and hepatic- and renal-function studies. The pharmacokinetic parameters calculated were Cmax, Tmax, absorption constant (Ka), elimination constant (Kel), AUC2–24h, AUC0-∞, elimination phase (t½β), volume of distribution (Vd), and urinary excretion rate. Results: Five subjects (3 men, 2 women; mean age, 28 years [range, 18–34 years]) were included in the study. One hour after drug administration the following values were obtained: Cmax, 1.1 μg/mL; Tmax, 1.3 hours; Ka, 1.87 hours; Kel, 0.043 hours; AUC0–24h, 12.26 μg/mL · h; AUC0-∞, 19.84 μg/mL · h; t½β, 17.45 hours; Vd, 6.6 L/kg; and urinary excretion rate, 2.8 μg/h; these were mean values for the entire study group. The single dose was well tolerated by all subjects. Conclusions: The investigational generic SbV, Ulamina, was associated with linearelimination after IM administration of a single 5-mg/kg dose. A 2-compartment pharmacokinetic model was observed in

  7. Stripping voltammetric determination of mercury(II) at antimony-coated carbon paste electrode.

    PubMed

    Ashrafi, Amir M; Vytřas, Karel

    2011-10-15

    A new procedure was elaborated to determine mercury(II) using an anodic stripping square-wave voltammetry at the antimony film carbon paste electrode (SbF-CPE). In highly acidic medium of 1M hydrochloric acid, voltammetric measurements can be realized in a wide potential window. Presence of cadmium(II) allows to separate peaks of Hg(II) and Sb(III) and apparently catalyses reoxidation of electrolytically accumulated mercury, thus allowing its determination at ppb levels. Calibration dependence was linear up to 100 ppb Hg with a detection limit of 1.3 ppb. Applicability of the method was tested on the real river water sample.

  8. Preparation of superconductor precursor powders

    DOEpatents

    Bhattacharya, R.

    1998-08-04

    A process for the preparation of a precursor metallic powder composition for use in the subsequent formation of a superconductor. The process comprises the steps of providing an electrodeposition bath comprising an electrolyte medium and a cathode substrate electrode, and providing to the bath one or more soluble salts of one or more respective metals which are capable of exhibiting superconductor properties upon subsequent appropriate treatment. The bath is continually energized to cause the metallic and/or reduced particles formed at the electrode to drop as a powder from the electrode into the bath, and this powder, which is a precursor powder for superconductor production, is recovered from the bath for subsequent treatment. The process permits direct inclusion of all metals in the preparation of the precursor powder, and yields an amorphous product mixed on an atomic scale to thereby impart inherent high reactivity. Superconductors which can be formed from the precursor powder include pellet and powder-in-tube products. 7 figs.

  9. Preparation of superconductor precursor powders

    DOEpatents

    Bhattacharya, Raghunath; Blaugher, Richard D.

    1995-01-01

    A process for the preparation of a precursor metallic powder composition for use in the subsequent formation of a superconductor. The process comprises the steps of providing an electrodeposition bath comprising an electrolyte medium and a cathode substrate electrode, and providing to the bath one or more soluble salts of one or more respective metals, such as nitrate salts of thallium, barium, calcium, and copper, which are capable of exhibiting superconductor properties upon subsequent appropriate treatment. The bath is continually energized to cause the metallic particles formed at the electrode to drop as a powder from the electrode into the bath, and this powder, which is a precursor powder for superconductor production, is recovered from the bath for subsequent treatment. The process permits direct inclusion of thallium in the preparation of the precursor powder, and yields an amorphous product mixed on an atomic scale to thereby impart inherent high reactivity. Superconductors which can be formed from the precursor powder include pellet and powder-in-tube products.

  10. PAGOSA Sample Problem. Elastic Precursor

    SciTech Connect

    Weseloh, Wayne N.; Clancy, Sean Patrick

    2016-02-03

    A PAGOSA simulation of a flyer plate impact which produces an elastic precursor wave is examined. The simulation is compared to an analytic theory for the Mie-Grüneisen equation of state and an elastic-perfectly-plastic strength model.

  11. Antimony oxofluorides - a synthesis concept that yields phase pure samples and single crystals.

    PubMed

    Ali, Sk Imran; Johnsson, Mats

    2016-07-26

    The single crystals of the new isostructural compounds Sb3O4F and Y0.5Sb2.5O4F and the two previously known compounds M-SbOF and α-Sb3O2F5 were successfully grown by a hydrothermal technique at 230 °C. The new compound Sb3O4F crystallizes in the monoclinic space group P21/c; a = 5.6107(5) Å, b = 4.6847(5) Å, c = 20.2256(18) Å, β = 94.145(8)°, z = 4. The replacing part of Sb with Y means a slight increase in the unit cell dimensions. The compounds M-SbOF and α-Sb3O2F5 have not been grown as single crystals before and it can be concluded that hydrothermal synthesis has proved to be a suitable technique for growing single crystals of antimony oxofluorides because of the relatively low solubility of such compounds compared to other antimony oxohalides that most often have been synthesised at high temperatures by solid state reactions or gas-solid reactions.

  12. Effect of indium and antimony doping in SnS single crystals

    SciTech Connect

    Chaki, Sunil H. Chaudhary, Mahesh D.; Deshpande, M.P.

    2015-03-15

    Highlights: • Single crystals growth of pure SnS, indium doped SnS and antimony doped SnS by direct vapour transport (DVT) technique. • Doping of In and Sb occurred in SnS single crystals by cation replacement. • The replacement mechanism ascertained by EDAX, XRD and substantiated by Raman spectra analysis. • Dopants concentration affects the optical energy bandgap. • Doping influences electrical transport properties. - Abstract: Single crystals of pure SnS, indium (In) doped SnS and antimony (Sb) doped SnS were grown by direct vapour transport (DVT) technique. Two doping concentrations of 5% and 15% each were employed for both In and Sb dopants. Thus in total five samples were studied viz., pure SnS (S1), 5% In doped SnS (S2), 15% In doped SnS (S3), 5% Sb doped SnS (S4) and 15% Sb doped SnS (S5). The grown single crystal samples were characterized by evaluating their surface microstructure, stoichiometric composition, crystal structure, Raman spectroscopy, optical and electrical transport properties using appropriate techniques. The d.c. electrical resistivity and thermoelectric power variations with temperature showed semiconducting and p-type nature of the as-grown single crystal samples. The room temperature Hall Effect measurements further substantiated the semiconducting and p-type nature of the as-grown single crystal samples. The obtained results are deliberated in detail.

  13. Alkaline reforming of brominated fire-retardant plastics: fate of bromine and antimony.

    PubMed

    Onwudili, Jude A; Williams, Paul T

    2009-02-01

    High-impact polystyrene (HIPS) flame retarded with decabromodiphenyl ether (DDE), has been reacted in supercritical water from 380 to 450 degrees C and 21.5 to 31.0 MPa pressure in a batch reactor. Different concentrations of sodium hydroxide additive were used in situ to neutralize the corrosive inorganic bromine species released during the reactions. It appeared that supercritical water conditions lowered the decomposition temperature of both the fire-retardant DDE and HIPS. The reaction products included oils (up to 76 wt%), char (up to 18 wt%) and gas (up to 2.4 wt%) which was mainly methane. The presence of the alkaline water led to up to 97 wt% debromination of the product oil, producing virtually bromine-free oil feedstock. The removal of antimony from the oil product during processing was of the order of 98 wt%. The oil consisted of many single- and multiple-ringed aromatic compounds, many of which had alkyl substituents and/or aliphatic C(n)-bridges (n=1-4). The major single-ringed compounds included toluene, xylenes, ethylbenzene, propylbenzene and alpha-methylstyrene. Bibenzyl (diphenylethane), stilbene, diphenylmethane, diphenylpropane, diphenylcyclopropane, diphenylpropene, diphenylbutane, diphenylbutene and diphenylbuta-1,3-diene were the major C(n)-bridged compounds. Diphenyl ether and acetophenone were the major oxygenated compounds found. The process thus has the potential to produce bromine-free and antimony-free oils from fire-retardant plastics.

  14. Application of Hyphenated Techniques in Speciation Analysis of Arsenic, Antimony, and Thallium

    PubMed Central

    Michalski, Rajmund; Szopa, Sebastian; Jabłońska, Magdalena; Łyko, Aleksandra

    2012-01-01

    Due to the fact that metals and metalloids have a strong impact on the environment, the methods of their determination and speciation have received special attention in recent years. Arsenic, antimony, and thallium are important examples of such toxic elements. Their speciation is especially important in the environmental and biomedical fields because of their toxicity, bioavailability, and reactivity. Recently, speciation analytics has been playing a unique role in the studies of biogeochemical cycles of chemical compounds, determination of toxicity and ecotoxicity of selected elements, quality control of food products, control of medicines and pharmaceutical products, technological process control, research on the impact of technological installation on the environment, examination of occupational exposure, and clinical analysis. Conventional methods are usually labor intensive, time consuming, and susceptible to interferences. The hyphenated techniques, in which separation method is coupled with multidimensional detectors, have become useful alternatives. The main advantages of those techniques consist in extremely low detection and quantification limits, insignificant interference, influence as well as high precision and repeatability of the determinations. In view of their importance, the present work overviews and discusses different hyphenated techniques used for arsenic, antimony, and thallium species analysis, in different clinical, environmental and food matrices. PMID:22654649

  15. [Liposomal amphotericin B treatment of cutaneous leishmaniasis contracted in Djibouti and resistant to meglumine antimoniate].

    PubMed

    Rapp, C; Imbert, P; Darie, H; Simon, F; Gros, P; Debord, T; Roué, R

    2003-08-01

    Pentavalent antimony (PA) compounds remain the main therapeutic agents of cutaneous leishmaniasis (CL). CL infection resistant to PA is difficult to cure, limited by severe side effects and requiring a long course treatment of parenteral administration of recommended second line drugs. We report a case of CL unresponsive to meglumine antimoniate contracted in Djibouti, successfully treated with a short course treatment of AmBisome. In this case the subject had a recurrent thick crusted erythematous lesion on his left elbow associated with spreading micropapula on arms and thorax. The diagnosis of CL was confirmed by direct examination and genomic amplification by PCR of skin samples, cultures were negative. A short course treatment of parenteral AmBisome (18 mg/kg) has lead to clinical cure with no side effects and no relapse. In our hospital, the high cost of medication was counterbalanced by easiest administration, reduction of hospitalization duration, absence of adverse events and a gain of comfort. For this patient, a short course treatment of AmBisome proved to be a suitable alternative to traditional drugs used in CL resistant to PA.

  16. A Black Phosphate Conversion Coating on Steel Surface Using Antimony(III)-Tartrate as an Additive

    NASA Astrophysics Data System (ADS)

    Li, Feng; Wang, Guiping

    2016-05-01

    A novel black phosphate conversion coating was formed on steel surface through a Zn-Mn phosphating bath containing mainly ZnO, H3PO4, Mn(H2PO4)2, and Ca(NO3)2, where antimony(III)-tartrate was used as the blackening agent of phosphatization. The surface morphology and composition of the coating were characterized by scanning electron microscopy, energy dispersion spectroscopy, and x-ray photoelectron spectroscopy. Corrosion resistance of the coating was studied by potentiodynamic polarization curves and electrochemical impedance spectroscopy. The pH value of the solution had significant influence on the formation and corrosion resistance of the coating. The experimental results indicated that the Sb plays a vital role in the blackening of phosphate conversion coating. The optimal concentration of antimony(III)-tartrate in the phosphating bath used in this experiment was 1.0 g L-1, as higher values reduced the corrosion resistance of the coating. In addition, by saponification and oil seals, the corrosion duration of the black phosphate coating in a copper sulfate spot test can be as long as 20 min.

  17. Influence of phosphoric acid on the electrochemistry of lead electrodes in sulfuric acid electrolyte containing antimony

    NASA Astrophysics Data System (ADS)

    Venugopalan, S.

    The influence of phosphoric acid (0 to 40 g 1 -1) on the Pb/PbSO 4 reaction and the kinetics of hydrogen evolution on pure, smooth lead and lead alloy electrodes is studied via galvanostatic polarization in the linear and Tafel domains with and without antimony (0 to 10 mg 1 -1) addition to the H 2SO 4 (3 to 10 M) electrolyte. Phosphoric acid is found to offset significantly the adverse effect of antimony. H 3PO 4 is also found to increase the hydrogen overpotential without affecting the Pb/PbSO 4 reaction. This implies that the open-circuit corrosion of lead and the consequent hydrogen evolution rate on lead are reduced in the presence of H 3PO 4. The beneficial effects of H 3PO 4 additive are found to be optimum at around 20 g 1 -1. Suppression of hydrogen evolution on the negative electrode, a crucial criterion for sealed cell operation, can be achieved using a H 3PO 4 additive.

  18. Heterogeneous dislocation nucleation in single crystal copper-antimony solid-solution alloys

    NASA Astrophysics Data System (ADS)

    Rajgarhia, Rahul K.; Spearot, Douglas E.; Saxena, Ashok

    2009-07-01

    Molecular dynamics (MD) simulations are employed to study the partial dislocation nucleation process in single crystal copper with varying concentrations of antimony (0.0-2.0 at%Sb) under uniaxial tension. A well-established embedded-atom method potential is used to represent the Cu-Cu interactions and a recently developed Lennard-Jones potential is used for the Cu-Sb and Sb-Sb interactions. Antimony atoms are randomly distributed as substitutional defects in the Cu single crystal. MD simulations indicate that the tensile stress required for partial dislocation nucleation in the crystal decreases with increasing concentration of Sb. The strain field around Sb dopant atoms in the Cu lattice reduces the unstable stacking fault energy, which promotes heterogeneous nucleation of partial dislocations and reduces the tensile stresses required for plastic deformation. In addition, the role of Sb on the reduction in the stress required for dislocation nucleation is found to be orientation-dependent. Finally, both temperature and Sb distribution play a role in the statistical variation of the stress required for heterogeneous partial dislocation nucleation; this variation is maximum at moderate levels of Sb concentration (0.20-0.50 at%Sb).

  19. Measurements of spin life time of an antimony-bound electron in silicon

    NASA Astrophysics Data System (ADS)

    Lu, T. M.; Bishop, N. C.; Tracy, L. A.; Blume-Kohout, R.; Pluym, T.; Wendt, J. R.; Dominguez, J.; Lilly, M. P.; Carroll, M. S.

    2013-03-01

    We report our measurements of spin life time of an antimony-bound electron in silicon. The device is a double-top-gated silicon quantum dot with antimony atoms implanted near the quantum dot region. A donor charge transition is identified by observing a charge offset in the transport characteristics of the quantum dot. The tunnel rates on/off the donor are first characterized and a three-level pulse sequence is then used to measure the spin populations at different load-and-wait times in the presence of a fixed magnetic field. The spin life time is extracted from the exponential time dependence of the spin populations. A spin life time of 1.27 seconds is observed at B = 3.25 T. This work was performed, in part, at the Center for Integrated Nanotechnologies, a U.S. DOE, Office of Basic Energy Sciences user facility. The work was supported by the Sandia National Laboratories Directed Research and Development Program. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  20. Organically complexed iron enhances bioavailability of antimony to maize (Zea mays) seedlings in organic soils.

    PubMed

    Ptak, Corey; McBride, Murray

    2015-12-01

    Antimony (Sb) is a metalloid belonging to group 15 of the periodic table. Chemical similarities between arsenic (As) and Sb produce concerns about potential health effects of Sb and enrichment in the environment. Antimony is found in oxic environments predominately as an oxyanionic species, antimonite (Sb[OH](6-)). As a result of its net negative charge, Sb[OH](6-) was not initially predicted to have strong interactions with natural organic matter. Oxyanionic species could bind the negatively charged organic matter via a ternary complexation mechanism, in which cationic metals mediate the strong association between organic matter functional groups and oxyanions. However, these interactions are poorly understood in how they influence the bioavailability of oxyanionic contaminants to plants. Iron (Fe) additions to organic soils have been found to increase the number of organically complexed Fe sites suitable for Sb exchange, resulting in a reduced bioavailable fraction of Sb. The bioavailability of Sb to maize seedlings as a function of organically complexed Fe was examined using a greenhouse study. A significant increase in plant tissue Sb was observed as organically complexed Fe increased, which was not predicted by methods commonly used to assess bioavailable Sb. Extraction of soils with organic acids common to the maize rhizosphere suggested that organic acid exudation can readily mobilize Sb bound by organic Fe complexes.

  1. Migration of antimony from PET containers into regulated EU food simulants.

    PubMed

    Sánchez-Martínez, María; Pérez-Corona, Teresa; Cámara, Carmen; Madrid, Yolanda

    2013-11-15

    Antimony migration from polyethylene terephthalate (PET) containers into aqueous (distilled water, 3% acetic acid, 10% and 20% ethanol) and fatty food simulants (vegetable oil), as well as into vinegar, was studied. Test conditions were according to the recent European Regulation 10/2011 (EU, 2011). Sb migration was assayed by ICP-MS and HG-AFS. The results showed that Sb migration values ranged from 0.5 to 1.2μg Sb/l, which are far below the maximum permissible migration value for Sb, 40μg Sb/kg, (EU, Regulation 10/2011). Parameters as temperature and bottle re-use influence were studied. To assess toxicity, antimony speciation was performed by HPLC-ICP-MS and HG-AFS. While Sb(V) was the only species detected in aqueous simulants, an additional species (Sb-acetate complex) was measured in wine vinegar. Unlike most of the studies reported in the literature, migration tests were based on the application of the EU directive, which enables comparison and harmonisation of results.

  2. A Telomeric Cluster of Antimony Resistance Genes on Chromosome 34 of Leishmania infantum

    PubMed Central

    Tejera Nevado, Paloma; Bifeld, Eugenia; Höhn, Katharina

    2016-01-01

    The mechanisms underlying the drug resistance of Leishmania spp. are manifold and not completely identified. Apart from the highly conserved multidrug resistance gene family known from higher eukaryotes, Leishmania spp. also possess genus-specific resistance marker genes. One of them, ARM58, was first identified in Leishmania braziliensis using a functional cloning approach, and its domain structure was characterized in L. infantum. Here we report that L. infantum ARM58 is part of a gene cluster at the telomeric end of chromosome 34 also comprising the neighboring genes ARM56 and HSP23. We show that overexpression of all three genes can confer antimony resistance to intracellular amastigotes. Upon overexpression in L. donovani, ARM58 and ARM56 are secreted via exosomes, suggesting a scavenger/secretion mechanism of action. Using a combination of functional cloning and next-generation sequencing, we found that the gene cluster was selected only under antimonyl tartrate challenge and weakly under Cu2+ challenge but not under sodium arsenite, Cd2+, or miltefosine challenge. The selective advantage is less pronounced in intracellular amastigotes treated with the sodium stibogluconate, possibly due to the known macrophage-stimulatory activity of this drug, against which these resistance markers may not be active. Our data point to the specificity of these three genes for antimony resistance. PMID:27324767

  3. Structural and optical study on antimony-silicate glasses doped with thulium ions.

    PubMed

    Dorosz, D; Zmojda, J; Kochanowicz, M; Miluski, P; Jelen, P; Sitarz, M

    2015-01-05

    Structural, spectroscopic and thermal properties of SiO₂-Al₂O₃-Sb₂O₃-Na₂O glass system doped with 0.2 mol% Tm₂O₃ have been presented. Synthesis of antimony-silicate glasses with relatively low phonon energy (600 cm(-1), which implicates a small non-radiative decay rate) was performed by conventional high-temperature melt-quenching methods. The effect of SiO₂/Sb₂O₃ ratio in fabricated Tm(3+) doped glass on thermal, structural and luminescence properties was investigated. On the basis of structural investigations decomposition of absorption bands in the infrared FTIR region was performed, thus determining that antimony ions are the only glass-forming ions, setting up the lattice of fabricated glasses. Luminescence band at the wavelength of 1.8 μm corresponding to (3)F₄→(3)H₆ transition in thulium ions was obtained under 795 nm laser pumping. It was observed that combination of relatively low phonon energy and greater separation of optically active centers in the fabricated glasses influenced in decreasing the luminescence intensity at 1800 nm.

  4. Evaluation of antimony microparticles supported on biochar for application in the voltammetric determination of paraquat.

    PubMed

    Gevaerd, Ava; de Oliveira, Paulo R; Mangrich, Antonio S; Bergamini, Márcio F; Marcolino-Junior, Luiz H

    2016-05-01

    This work describes the construction and application of carbon paste electrodes modified with biochar and antimony microparticles (SbBCPE) for voltammetric determination of paraquat using a simple and sensitive procedure based on voltammetric stripping analysis. Some parameters such as amount of biochar and antimony used in the composition of the carbon paste and instrumental parameters were examined in detail. Under optimized conditions, an analytical curve was obtained for paraquat determination employing SbBCPE, which showed a linear response ranging from 0.2 to 2.9 μmol L(-1), with limit of detection and quantification of 34 nmol L(-1) and 113 nmol L(-1), respectively, after paraquat pre-concentration of 120 s. The repeatability study presented a RSD=2.0% for 10 consecutive measurements using the same electrode surface and the reproducibility study showed a RSD=2.7% for measurements with 10 different electrode surfaces. The proposed sensor was successfully applied for paraquat determination in tap water and citric fruit juice spiked samples and good recoveries were obtained without any sample pre-treatment, showing its promising analytical performance.

  5. Growth of antimony doped P-type zinc oxide nanowires for optoelectronics

    DOEpatents

    Wang, Zhong Lin; Pradel, Ken

    2016-09-27

    In a method of growing p-type nanowires, a nanowire growth solution of zinc nitrate (Zn(NO.sub.3).sub.2), hexamethylenetetramine (HMTA) and polyethylenemine (800 M.sub.w PEI) is prepared. A dopant solution to the growth solution, the dopant solution including an equal molar ration of sodium hydroxide (NaOH), glycolic acid (C.sub.2H.sub.4O.sub.3) and antimony acetate (Sb(CH.sub.3COO).sub.3) in water is prepared. The dopant solution and the growth solution combine to generate a resulting solution that includes antimony to zinc in a ratio of between 0.2% molar to 2.0% molar, the resulting solution having a top surface. An ammonia solution is added to the resulting solution. A ZnO seed layer is applied to a substrate and the substrate is placed into the top surface of the resulting solution with the ZnO seed layer facing downwardly for a predetermined time until Sb-doped ZnO nanowires having a length of at least 5 .mu.m have grown from the ZnO seed layer.

  6. Investigation of Sb-Containing Precursors for Cu(In, Ga)Se2 Thin Films Through Design of Experiments

    SciTech Connect

    Mansfield, Lorelle M.; To, Bobby; Reedy, Robert C.; Young, Matthew R.; Bowers, Karen; Ramanathan, Kannan

    2016-11-21

    The Design of Experiments (DoE) module in JMP statistical software was used to determine the best parameters for Sb-containing CIGS precursors with a fixed selenization step. Solar cells were fabricated and measured for all completed films. The most important factor influencing the current-voltage device parameters was identified as the temperature and antimony flux interaction. The DoE prediction profiler and predictive contour plots provided guidance to further improve the device parameters. In one follow-up run, we increased device efficiency from 14.9% to 15.5% Additional gains in efficiency to 16.9% were realized by introducing an intentional Ga gradient and an antireflective coating.

  7. Two successive single crystal phase transitions involving the coordination sphere of antimony in PhSb(dmit), the first organo-antimony(III) dithiolene complex.

    PubMed

    Avarvari, N; Faulques, E; Fourmigué, M

    2001-05-21

    PhSb(dmit) (dmit(2)(-), 4,5-dithiolato-1,3-dithiole-2-thione), the first neutral organo-antimony dithiolene complex, has been synthesized by addition of PhSbCl(2) on a suspension of Na(2)(dmit). The complex was characterized by spectroscopic ((1)H and (13)C NMR and IR) methods and elemental analysis. Its crystal structure was determined by X-ray diffraction at room temperature in the monoclinic P2(1)/c space group, with a = 12.580(3), b = 8.9756(18), c = 15.905(3) A, beta = 109.06(3) degrees, V = 1697.5(6) A(3), Z = 4. A coordinating THF molecule was found in the structure and the coordination geometry around the antimony atom is of distorted pseudopentagonal bipyramid type, if taking into account the Sb.O and secondary Sb.S interactions, as well as the stereochemically active 5s(2) lone pair. The intermolecular Sb.S and S.S contacts, shorter than the sum of van der Waals radii of corresponding atoms, lead to the formation of a three-dimensional polymeric network in the solid state. A second X-ray diffraction experiment, performed at 85 K, revealed a very similar monoclinic unit cell with the noncentrosymmetrical space group P2(1) with a = 12.613(3), b = 8.9876(18), c = 15.109(3) A, beta = 107.01(3) degrees, V = 1637.8(6), Z = 4. The structural differences with the first one are basically due to the rotation of the THF ligand in the coordination sphere of the antimony center, leading to the loss of every inversion center found at room temperature. A temperature variable X-ray diffraction study on a PhSb(dmit) single-crystal allowed the detection, with a remarkable accuracy, of two successive first-order phase transitions, the first occurring at T = 162.5 K, while the second was observed at T = 182.5 K. Subsequently, a third set of X-ray data was collected at 180 K and the resulting structure (monoclinic, P2(1)/c, a = 16.736(3), b = 8.9653(18), c = 33.132(7) A, beta = 91.98(3) degrees, V = 4968.2(17), Z = 12) derives from the two others by a common b axis, a 3-fold

  8. Precursor polymer compositions comprising polybenzimidazole

    SciTech Connect

    Klaehn, John R.; Peterson, Eric S.; Orme, Christopher J.

    2015-07-14

    Stable, high performance polymer compositions including polybenzimidazole (PBI) and a melamine-formaldehyde polymer, such as methylated, poly(melamine-co-formaldehyde), for forming structures such as films, fibers and bulky structures. The polymer compositions may be formed by combining polybenzimidazole with the melamine-formaldehyde polymer to form a precursor. The polybenzimidazole may be reacted and/or intertwined with the melamine-formaldehyde polymer to form the polymer composition. For example, a stable, free-standing film having a thickness of, for example, between about 5 .mu.m and about 30 .mu.m may be formed from the polymer composition. Such films may be used as gas separation membranes and may be submerged into water for extended periods without crazing and cracking. The polymer composition may also be used as a coating on substrates, such as metal and ceramics, or may be used for spinning fibers. Precursors for forming such polymer compositions are also disclosed.

  9. Chemical vapor generation for sample introduction into inductively coupled plasma atomic emission spectroscopy: vaporization of antimony(III) with bromide.

    PubMed

    Lopez-Molinero, A; Mendoza, O; Callizo, A; Chamorro, P; Castillo, J R

    2002-10-01

    A new method for antimony determination in soils is proposed. It is based on the chemical vapor generation of Sb(III) with bromide, after a reaction in sulfuric acid media and transport of the gaseous phase into an inductively coupled plasma for atomic emission spectrometry. The experimental variables influencing the method were delimited by experimental design and the most important were finally optimized by the modified Simplex method. In optimized conditions the method involves the reaction of 579 microl concentrated sulfuric acid with 120 microl 5% w/v KBr and 250 microl antimony solution. Measurement of antimony emission intensity at 217.581 nm provides a method with an absolute detection limit of 3.5 ng and a precision (RSD) of 5.8% for the injection of five replicates of 175 ng Sb(III) (250 microl of 0.7 microg ml(-1) solution). The interference of common anions and cations on the antimony signal was evaluated. A 21% Sb(III) volatilization efficiency was calculated from the mean of six experiments at optimum conditions. The accuracy of the methodology was checked by the analysis of one standard reference soil after acid decomposition heating in a microwave oven.

  10. Identification of antimony resistance markers in Leishmania tropica field isolates through a cDNA-AFLP approach.

    PubMed

    Kazemi-Rad, Elham; Mohebali, Mehdi; Khadem-Erfan, Mohammad Bagher; Saffari, Mojtaba; Raoofian, Reza; Hajjaran, Homa; Hadighi, Ramtin; Khamesipour, Ali; Rezaie, Sassan; Abedkhojasteh, Hoda; Heidari, Mansour

    2013-10-01

    Pentavalent antimonial compounds have been the first line therapy for leishmaniasis; unfortunately the rate of treatment failure of anthroponotic cutaneous leishmaniasis (ACL) is increasing due to emerging of drug resistance. Elucidation of the molecular mechanisms operating in antimony resistance is critical for development of new strategies for treatment. Here, we used a cDNA-AFLP approach to identify gene(s) which are differentially expressed in resistant and sensitive Leishmania tropica field isolates. We identified five genes, aquaglyceroporin (AQP1) acts in drug uptake, ATP-binding cassette (ABC) transporter (MRPA) involved in sequestration of drug, phosphoglycerate kinase (PGK) implicated in glycolysis metabolism, mitogen activated protein kinase (MAPK) and protein tyrosine phosphatase (PTP) responsible for phosphorylation pathway. The results were confirmed using real time RT-PCR which revealed an upregulation of MRPA, PTP and PGK genes and downregulation of AQP1 and MAPK genes in resistant isolate. To our knowledge, this is the first report of identification of PTP and PGK genes potentially implicated in resistance to antimonials. Our findings support the idea that distinct biomolecules might be involved in antimony resistance in L. tropica field isolates.

  11. Successful treatment of imported mucosal Leishmania infantum leishmaniasis with miltefosine after severe hypokalemia under meglumine antimoniate treatment.

    PubMed

    Neumayr, Andreas L C; Walter, Clemens; Stoeckle, Marcel; Braendle, Natalie; Glatz, Kathrin; Blum, Johannes A

    2012-01-01

    Old World mucosal leishmaniasis is a rare but regularly reported disease in Southern Europe. We report the case of a 64-year-old woman who developed severe hypokalemia under meglumine antimoniate treatment and was successfully treated under second line therapy with miltefosine.

  12. Soluble Precursor Route to Polyanilines

    DTIC Science & Technology

    1993-01-01

    condensation were not successful, but further work produced polymer under the following conditions: Synthesis Diketone I (2.40 g, 10.0 mmol) in 10 mL...goal of producing a processible form of the conducting polymer polyaniline (PANI), the Phase I program concentrated on development of the synthesis of...extension of the original research to a Phase II effort. Diketone - Diamine Polycondensation Towards a Soluble PAni Precursor To achieve the

  13. Nucleation precursors in protein crystallization

    PubMed Central

    Vekilov, Peter G.; Vorontsova, Maria A.

    2014-01-01

    Protein crystal nucleation is a central problem in biological crystallography and other areas of science, technology and medicine. Recent studies have demonstrated that protein crystal nuclei form within crucial precursors. Here, methods of detection and characterization of the precursors are reviewed: dynamic light scattering, atomic force microscopy and Brownian microscopy. Data for several proteins provided by these methods have demonstrated that the nucleation precursors are clusters consisting of protein-dense liquid, which are metastable with respect to the host protein solution. The clusters are several hundred nanometres in size, the cluster population occupies from 10−7 to 10−3 of the solution volume, and their properties in solutions supersaturated with respect to crystals are similar to those in homogeneous, i.e. undersaturated, solutions. The clusters exist owing to the conformation flexibility of the protein molecules, leading to exposure of hydrophobic surfaces and enhanced intermolecular binding. These results indicate that protein conformational flexibility might be the mechanism behind the metastable mesoscopic clusters and crystal nucleation. Investigations of the cluster properties are still in their infancy. Results on direct imaging of cluster behaviors and characterization of cluster mechanisms with a variety of proteins will soon lead to major breakthroughs in protein biophysics. PMID:24598910

  14. Lithium-antimony-lead liquid metal battery for grid-level energy storage.

    PubMed

    Wang, Kangli; Jiang, Kai; Chung, Brice; Ouchi, Takanari; Burke, Paul J; Boysen, Dane A; Bradwell, David J; Kim, Hojong; Muecke, Ulrich; Sadoway, Donald R

    2014-10-16

    The ability to store energy on the electric grid would greatly improve its efficiency and reliability while enabling the integration of intermittent renewable energy technologies (such as wind and solar) into baseload supply. Batteries have long been considered strong candidate solutions owing to their small spatial footprint, mechanical simplicity and flexibility in siting. However, the barrier to widespread adoption of batteries is their high cost. Here we describe a lithium-antimony-lead liquid metal battery that potentially meets the performance specifications for stationary energy storage applications. This Li||Sb-Pb battery comprises a liquid lithium negative electrode, a molten salt electrolyte, and a liquid antimony-lead alloy positive electrode, which self-segregate by density into three distinct layers owing to the immiscibility of the contiguous salt and metal phases. The all-liquid construction confers the advantages of higher current density, longer cycle life and simpler manufacturing of large-scale storage systems (because no membranes or separators are involved) relative to those of conventional batteries. At charge-discharge current densities of 275 milliamperes per square centimetre, the cells cycled at 450 degrees Celsius with 98 per cent Coulombic efficiency and 73 per cent round-trip energy efficiency. To provide evidence of their high power capability, the cells were discharged and charged at current densities as high as 1,000 milliamperes per square centimetre. Measured capacity loss after operation for 1,800 hours (more than 450 charge-discharge cycles at 100 per cent depth of discharge) projects retention of over 85 per cent of initial capacity after ten years of daily cycling. Our results demonstrate that alloying a high-melting-point, high-voltage metal (antimony) with a low-melting-point, low-cost metal (lead) advantageously decreases the operating temperature while maintaining a high cell voltage. Apart from the fact that this

  15. Antimony and arsenic behaviours in soils from three abandoned gold mining areas in northern Portugal

    NASA Astrophysics Data System (ADS)

    Carvalho, Paula; Neiva, Ana; Silva, Maria

    2013-04-01

    The Valongo anticline located 18 km at East of Porto is characterized by the occurrence of several gold deposits, which were exploited until the end of the nineteenth century. This anticline comprises Cambrian to Carboniferous metasediments. The Cambrian schist-graywacke complex crops out in the western limb of the anticline and is intersected by several Sb-Au quartz veins, mainly Montalto and Tapada. At the eastern limb of the anticline, As-Au quartz veins cut Ordovician black slates and were exploited at the Banjas mine. The Sb-Au quartz veins contain mainly quartz, arsenopyrite, pyrrhotite, pyrite, marcasite, sphalerite, chalcophyrite, galena, gold, tetrahedrite, jamesonite, plagionite, berthierite, stibnite, antimony and carbonates. The As-Au quartz veins consist of quartz, arsenopyrite, pyrite, pyrrhotite, cobaltite, glaucodote, sphalerite, boulangerite, tetrahedrite and siderite. Stibnite and arsenopyrite are the most abundant sulphides in Sb-Au and As-Au quartz veins, respectively. Therefore, antimony and arsenic are potential contaminants in the surrounding environments of these old mines. The principal component analysis (PCA) was applied to organic matter, pH, cation exchange capacity, clay size particle and reducible, oxidizable and aqua regia Fe, Mn, As and Sb concentrations obtained by the BCR method in 29 soil samples. The PCA shows a substantial distinction between Sb and As behaviours in soils from the old mining areas of Montalto, Tapada and Banjas. The arsenic concentration ranges between 16.98 mg/kg and 1116 mg/kg, whereas the Sb concentration ranges from 6.4 mg/kg to 21775 mg/kg. The antimony is statistically more correlated with Fe and Mn in the oxides fraction, whereas As in the reducible fraction dependents on pH values. Moreover, Fe and Mn concentrations in the oxidizable fraction are highly correlated with the organic matter, suggesting that pyrite, the main host mineral of Fe, was probably totally altered. However, the As concentration in

  16. Anti-plasmodial activity of aroylhydrazone and thiosemicarbazone iron chelators: effect on erythrocyte membrane integrity, parasite development and the intracellular labile iron pool.

    PubMed

    Walcourt, Asikiya; Kurantsin-Mills, Joseph; Kwagyan, John; Adenuga, Babafemi B; Kalinowski, Danuta S; Lovejoy, David B; Lane, Darius J R; Richardson, Des R

    2013-12-01

    Iron chelators inhibit the growth of the malaria parasite, Plasmodium falciparum, in culture and in animal and human studies. We previously reported the anti-plasmodial activity of the chelators, 2-hydroxy-1-naphthylaldehyde isonicotinoyl hydrazone (311), 2-hydroxy-1-naphthylaldehyde 4-methyl-3-thiosemicarbazone (N4mT), and 2-hydroxy-1-naphthylaldehyde 4-phenyl-3-thiosemicarbazone (N4pT). In fact, these ligands showed greater growth inhibition of chloroquine-sensitive (3D7) and chloroquine-resistant (7G8) strains of P. falciparum in culture compared to desferrioxamine (DFO). The present study examined the effects of 311, N4mT and N4pT on erythrocyte membrane integrity and asexual parasite development. While the characteristic biconcave disk shape of the erythrocytes was unaffected, the chelators caused very slight hemolysis at IC50 values that inhibited parasite growth. The chelators 311, N4mT and N4pT affected all stages of the intra-erythrocytic development cycle (IDC) of P. falciparum in culture. However, while these ligands primarily affected the ring-stage, DFO inhibited primarily trophozoite and schizont-stages. Ring, trophozoite and schizont-stages of the IDC were inhibited by significantly lower concentrations of 311, N4mT, and N4pT (IC50=4.45±1.70, 10.30±4.40, and 3.64±2.00μM, respectively) than DFO (IC50=23.43±3.40μM). Complexation of 311, N4mT and N4pT with iron reduced their anti-plasmodial activity. Estimation of the intracellular labile iron pool (LIP) in erythrocytes showed that the chelation efficacy of 311, N4mT and N4pT corresponded to their anti-plasmodial activities, suggesting that the LIP may be a potential source of non-heme iron for parasite metabolism within the erythrocyte. This study has implications for malaria chemotherapy that specifically disrupts parasite iron utilization.

  17. New Worlds Observer Precursor Mission

    NASA Astrophysics Data System (ADS)

    Lillie, C. F.; Lo, A. S.; Dailey, D.; Glassman, T. M.

    2007-06-01

    The New Worlds Observer architecture uses an external occulter to extinguish the on-axis light from a star and a separate telescope to collect the light from objects around that star, such as planets and debris disks. The separation of the starlight suppression capability from the photon collection capability makes the New Worlds Observer architecture very flexible. This paper describes NWO concepts ranging from low-cost precursor missions to Terrestrial Planet Finding (TPF) missions, and provides a path that extends beyond TPF to Planet-Imager and LifeFinder. Low cost precursor missions could be launched on a Minotaur using a small(~10 meter) occulter to work with a small(~0.5 m), telescope. Intermediate precursor missions could be accomplished by launching a larger occulter as a secondary payload to work with existing telescopes such as SOFIA or JWST. The former may allow direct detection of known giant planets, while the latter has the potential to discover Exo-Earths. A full TPF mission would consists of a large occulter working with a dedicated telescope; this can potentially find many terrestrial planets, as well as perform a host of ancillary astronomy investigations such as imaging debris disks and characterizing atmospheres of Jovian planets, as well as making general astrophysics observations. By utilizing the in space servicing capabilities that may be developed for the Exploration program, the lifetime of these occulters may be greatly extended by refueling and repair. In the future, larger occulters (>100 m) could be assembled on orbit. Thus, when coupled with a large telescope, the NWO architecture provides a path towards Lifefinder. NWO is a flexible architecture that allows scalability on all levels to suit the budget available for Exo-Planet Missions.

  18. Precursors of Short Gamma-Ray Bursts

    NASA Technical Reports Server (NTRS)

    Troja, E.; Rosswog, S.; Gehrels, N.

    2010-01-01

    We carried out a systematic search of precursors on the sample of short GRBs observed by Swift. We found that approx. 8-10% of short GRBs display such early episode of emission. One burst (GRB 090510) shows two precursor events, the former approx.13 s and the latter approx. 0.5 s before the GRB. We did not find any substantial difference between the precursor and the main GRB emission, and between short GRBs with and without precursors. We discuss possible mechanisms to reproduce the observed precursor emission within the scenario of compact object mergers. The implications of our results on quantum gravity constraints are also discussed.

  19. In-situ growth of antimony sulfide in carbon nanoparticle matrix: Enhanced electrocatalytic activity as counter electrode in dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Sun, Panpan; Zhang, Ming; Ai, Changzhi; Wu, Zhixin; Lu, Shuang; Zhang, Xintong; Huang, Niu; Sun, Yihua; Sun, Xiaohua

    2016-07-01

    Considering the undesirable electrocatalytic activity toward I-/I3- redox system of prinstine antimony sulfide (Sb2S3) fabricated with the existing conditions, a mesoporous carbon nanoparticle film (CNP) is introduced here for in-situ growth of Sb2S3 to construct a Sb2S3@CNP hybrid catalyst. Based on a Sb-thiourea precursor solution, in-situ growth of Sb2S3 can be achieved via solution deposition (denoted as Sb2S3@CNP-S) as well as atmospheric pressure thermal evaporation (denoted as Sb2S3@CNP-T) in CNP matrix. Structural characterizations indicate that Sb2S3 particles have well dispersed in the pores of CNP matrix. Because of the introduction of porous and conductive CNP matrix to support Sb2S3, the hybrid catalyst exhibits lower charge transfer resistance at the catalyst/electrolyte interface and higher electrocatalytic activity. When used as counter electrode (CE) for dye-sensitized solar cells (DSSCs), devices using Sb2S3@CNP hybrid catalyst as CE produce fill factor of 67.6% and 66.3%, which is significantly higher than that using pristine Sb2S3 fabricated in our previous work (52.8%). Finally, the corresponding power conversion efficiencies reach 6.69% (Sb2S3@CNP-S) and 6.24% (Sb2S3@CNP-T), respectively, which are comparable to that using Pt CE measured under the same conditions (6.74%).

  20. Sequential solvent extraction for forms of antimony in five selected coals

    USGS Publications Warehouse

    Qi, C.; Liu, Gaisheng; Kong, Y.; Chou, C.-L.; Wang, R.

    2008-01-01

    Abundance of antimony in bulk samples has been determined in five selected coals, three coals from Huaibei Coalfield, Anhui, China, and two from the Illinois Basin in the United States. The Sb abundance in these samples is in the range of 0.11-0.43 ??g/g. The forms of Sb in coals were studied by sequential solvent extraction. The six forms of Sb are water soluble, ion changeable, organic matter bound, carbonate bound, silicate bound, and sulfide bound. Results of sequential extraction show that silicate-bound Sb is the most abundant form in these coals. Silicate- plus sulfide-bound Sb accounts for more than half of the total Sb in all coals. Bituminous coals are higher in organic matterbound Sb than anthracite and natural coke, indicating that the Sb in the organic matter may be incorporated into silicate and sulfide minerals during metamorphism. ?? 2008 by The University of Chicago. All rights reserved.

  1. Synthesis and optical properties of antimony oxide glasses doped with holmium trioxide

    NASA Astrophysics Data System (ADS)

    Raghunatha, S.; Eraiah, B.

    2016-05-01

    Holmium doped lithium-antimony-lead borate glasses having 1mol% AgNO3 with composition 50B2O3-20PbO-25Sb2O3-5Li2O have been prepared using single step melt quenching technique. The XRD spectrum confirms amorphous nature of glasses. The optical absorbance studies were carried out on these glasses. The optical direct band gap energies were found to be in the range of 3.10 eV to 3.31 eV and indirect band gap energies were found to be in the range of 2.28 eV to 3.00 eV. The refractive indexes have been calculated by using Lorentz-Lorenz formula and the calculated values in the range of 2.31 to 2.37.

  2. Biological monitoring of exposures to aluminium, gallium, indium, arsenic, and antimony in optoelectronic industry workers.

    PubMed

    Liao, Y-H; Yu, H-S; Ho, C-K; Wu, M-T; Yang, C-Y; Chen, J-R; Chang, C-C

    2004-09-01

    The main objective of this study was to investigate aluminum, gallium, indium, arsenic, and antimony exposures on blood and urine levels in the optoelectronic workers. One hundred seventy subjects were enrolled in this cohort study. Whole blood and urine levels were determined by inductively coupled plasma-mass spectrometry. Blood indium and urine gallium and arsenic levels in the 103 workers were significantly higher than that in 67 controls during the follow-up period. In regression models, the significant risk factors of exposure were job title, preventive equipment, Quetelet's index, sex, and education level. The findings of this study suggest that gallium, indium, and arsenic exposure levels may affect their respective levels in blood and urine. The use of clean, preventive equipment is recommended when prioritizing the administration of safety and hygiene in optoelectronics industries.

  3. Controlled growth of antimony-doped tin dioxide thin films by atomic layer epitaxy

    NASA Astrophysics Data System (ADS)

    Viirola, H.; Niinistoe, L.

    1994-11-01

    Antimony-doped tin dioxide thin films were deposited on glass substrates by atomic layer epitaxy using SnCl4, SbCl5 and H2O as reactants. The growth experiments were carried out at 500 C. The effect of Sb doping on the growth rate, crystal texture and electrical and optical properties was studied. Spectrophotometry, secondary ion mass spectrometry, X-ray diffraction and electron spectroscopy for chemical analysis, as well as sheet resistance and Hall measurements were used to characterize the films. The films were highly uniform with only small thickness and sheet resistance variations. The films were polycrystalline with their crystallites having a preferred orientation, which depended on the Sb doping level and film thickness.

  4. Potentiometric stripping analysis (PSA) for monitoring of antimony in samples of vegetation from a mining area.

    PubMed

    Toro Gordillo, M C; Pinilla Gil, E; Rodríguez González, M A; Murciego Murciego, A; Ostapczuk, P

    2001-06-01

    A potentiometric stripping analysis (PSA) method has been developed and checked for the fast and reliable determination of antimony in vegetation samples of Cistus ladanifer from a mining area in Badajoz, Southwest Spain. The method, modified from previous PSA methods for Sb in environmental samples, is based on dry ashing of the homogenized leaves, dissolution in hydrochloric acid, and PSA analysis on a mercury film plated on to a glassy carbon disk electrode. The influence of experimental variables such as the deposition potential, the deposition time, the signal stability and the calibration parameters, has been investigated. The method has been compared with an independent technique (instrumental neutron activation analysis) by analysis of standards and reference materials and comparison of the results. As a result of automation of the PSA equipment, the proposed method enables unattended analysis of 20 digested samples in a total time of 2 h, thus providing a useful tool for Sb monitoring of a large number of samples.

  5. Rashba effect in single-layer antimony telluroiodide SbTeI

    NASA Astrophysics Data System (ADS)

    Zhuang, Houlong L.; Cooper, Valentino R.; Xu, Haixuan; Ganesh, P.; Hennig, Richard G.; Kent, P. R. C.

    2015-09-01

    Exploring spin-orbit coupling (SOC) in single-layer materials is important for potential spintronics applications. Using first-principles calculations, we show that single-layer antimony telluroiodide SbTeI behaves as a two-dimensional semiconductor exhibiting a G0W0 band gap of 1.82 eV. More importantly, we observe the Rashba spin splitting in the SOC band structure of single-layer SbTeI with a sizable Rashba coupling parameter of 1.39 eV Å , which is significantly larger than that of a number of two-dimensional systems including surfaces and interfaces. The low formation energy and real phonon modes of single-layer SbTeI imply that it is stable. Our study suggests that single-layer SbTeI is a candidate single-layer material for applications in spintronics devices.

  6. Synthesis and characterization of copper antimony tin sulphide thin films for solar cell applications

    NASA Astrophysics Data System (ADS)

    Ali, N.; Hussain, A.; Ahmed, R.; Wan Shamsuri, W. N.; Fu, Y. Q.

    2016-12-01

    Low price thin film modules based on Copper antimony tin sulphide (CATS) are introduced for solar harvesting to compete for the already developed compound semiconductors. Here, CATS thin films were deposited on soda lime glass by thermal evaporation technique followed by a rapid thermal annealing in an argon atmosphere. From Our XRD analysis, it was revealed that the annealed samples were poly-crystalline and their crystallinity was improved with increasing annealing temperature. The constituent elements and their corresponding chemical states were identified using X-ray photoelectron spectroscopy. The obtained optical band gap of 1.4 eV for CATS thin film is found nearly equal to GaAs - one of the highly efficient thin film material for solar cell technology. Furthermore, our observed good optical absorbance and low transmittance for the annealed CATS thin films in the visible region of light spectrum assured the aptness of the CATS thin films for solar cell applications.

  7. Synthesis of Antimony Nanotubes via Facile Template-Free Solvothermal Reactions

    NASA Astrophysics Data System (ADS)

    Li, Ruxue; Wang, Xiaohua; Wang, Xinwei; Zhang, Haoran; Pan, Jingxin; Tang, Jilong; Fang, Dan; Ma, Xiaohui; Li, Yongfeng; Yao, Bin; Fan, Jie; Wei, Zhipeng

    2016-11-01

    Uniform antimony (Sb) nanotubes were successfully synthesized via a facile solvothermal method without the need for any surfactants or templates. The Sb nanotubes are confirmed to be pure rhombohedral phase and have better crystallinity. These nanotubes show middle-hollow and open-ended structures, as well as multi-walled structures with the wall thickness of about 10 nm. Also, they have an average size of the diameter of about 50 nm and the length of about 350 nm. On the basis of the structural and morphological studies, a possible rolling mechanism is proposed to explain the formation of Sb nanotubes. It is expected that uniform Sb nanotubes can further be used in wide applications.

  8. Formation of the properties of antimony matrix alloys for frame-type composite materials

    NASA Astrophysics Data System (ADS)

    Gulevskii, V. A.; Antipov, V. I.; Vinogradov, L. V.; Kolmakov, A. G.; Lazarev, E. M.; Samarina, A. M.; Mukhina, Yu. E.

    2009-12-01

    A frame-type composite material (CM) produced upon impregnation represents a system consisting of a rigid porous frame and a matrix material filling its voids. When metals are used as a matrix material, they bring up specific problems related to melting of a metal, such as the thermal effect of the metal on the frame and the chemical interaction of the matrix and frame with the formation of brittle compounds. A CM that combines the best characteristics of its components can be produced. Since impregnation is, as a rule, performed under vacuum, melting of a matrix metal is accompanied by an increase in the evaporation rate. The evaporation of a matrix metal can be decreased by controlling its chemical composition, decreasing the melting temperature of the melt, and controlling the cooling rate. In this work, antimony alloys are used as a matrix material and their properties are studied.

  9. Sequential solvent extraction for forms of antimony in five selected coals

    SciTech Connect

    Qi, C.C.; Liu, G.J.; Kang, Y.; Chou, C.L.; Wang, R.W.

    2008-03-15

    Abundance of antimony in bulk samples has been determined in five selected coals, three coals from Huaibei Coalfield, Anhui, China, and two from the Illinois Basin in the United States. The Sb abundance in these samples is in the range of 0.11-0.43 {mu} g/g. The forms of Sb in coals were studied by sequential solvent extraction. The six forms of Sb are water soluble, ion changeable, organic matter bound, carbonate bound, silicate bound, and sulfide bound. Results of sequential extraction show that silicate-bound Sb is the most abundant form in these coals. Silicate-plus sulfide-bound Sb accounts for more than half of the total Sb in all coals. Bituminous coals are higher in organic matter bound Sb than anthracite and natural coke, indicating that the Sb in the organic matter may be incorporated into silicate and sulfide minerals during metamorphism.

  10. The electrical characterizations of selenium (Se) doped gallium antimony (GaSb) single crystal

    NASA Astrophysics Data System (ADS)

    Choudhari, Rashmi; Deshpande, Manisha; Maske, Dilip; Gadkari, Dattatray

    2016-05-01

    The growth of Se doped GaSb bulk crystal is carried out using Vertical directional solidification (VDS) technique. High purity Gallium and Antimony is taken as source material and selenium as doping material. From grown ingot substrate were obtained in wafer form using diamond cutter. The electrical characteristics such as Hall measurement is used to find the carrier concentration and mobility, while Van der pauw for measuring resistivity of the sample The GaSb:Se sample shows high resistivity and mobility. The grown crystal was detached from the ampoule wall with high crystal quality. The measured resistivity of GaSb:Se is 9.9×10-3ohm-cm, the mobility is 1464cm3/Vsec and carrier concentration is 5.08×1017 per cm3.

  11. Rashba effect in single-layer antimony telluroiodide SbTeI

    SciTech Connect

    Zhuang, Houlong L.; Cooper, Valentino R.; Xu, Haixuan; Ganesh, P.; Hennig, Richard G.; Kent, P. R. C.

    2015-09-04

    Exploring spin-orbit coupling (SOC) in single-layer materials is important for potential spintronics applications. In this paper, using first-principles calculations, we show that single-layer antimony telluroiodide SbTeI behaves as a two-dimensional semiconductor exhibiting a G0W0 band gap of 1.82 eV. More importantly, we observe the Rashba spin splitting in the SOC band structure of single-layer SbTeI with a sizable Rashba coupling parameter of 1.39 eV Å, which is significantly larger than that of a number of two-dimensional systems including surfaces and interfaces. The low formation energy and real phonon modes of single-layer SbTeI imply that it is stable. Finally, our study suggests that single-layer SbTeI is a candidate single-layer material for applications in spintronics devices.

  12. Distributions and impact factors of antimony in topsoils and moss in Ny-Ålesund, Arctic.

    PubMed

    Jia, Nan; Sun, Liguang; He, Xin; You, Kehua; Zhou, Xin; Long, Nanye

    2012-12-01

    The distribution of antimony (Sb) in topsoil and moss (Dicranum angustum) in disturbed and undisturbed areas, as well as coal and gangue, in Ny-Ålesund, Arctic was examined. Results show that the weathering of coal bed could not contribute to the increase of Sb concentrations in topsoil and moss in the study area. The distribution of Sb is partially associated with traffic and historical mining activities. The occurrence of the maximum Sb concentration is due to the contribution of human activities. In addition, the decrease of Sb content in topsoil near the coastline may be caused by the washing of seawater. Compared with topsoils, moss could be a useful tool for monitoring Sb in both highly and lightly polluted areas.

  13. Antimony uptake by Zea mays (L.) and Helianthus annuus (L.) from nutrient solution.

    PubMed

    Tschan, Martin; Robinson, Brett; Schulin, Rainer

    2008-04-01

    We investigated the extent of Sb uptake by maize (Zea mays) and sunflower (Helianthus annuus) from nutrient solutions containing concentrations from 3 to 24 mg/L of potassium antimonate, with the aim of determining the potential of Sb to enter the food chain. The maximum shoot Sb concentrations in Z. mays and H. annuus were 41 mg/kg and 77 mg/kg dry weight, respectively. There was no significant difference in Sb uptake between species. The average bioaccumulation coefficients (the plant/solution concentration quotients) were 1.02 and 1.93 for Z. mays and H. annuus, respectively. Phosphate addition did not affect plant growth or Sb uptake. Antimony uptake by both Z. mays and H. annuus is unlikely to pose a health risk to animals and humans.

  14. Suppression of Grain Growth by Additive in Nanostructured P-type Bismuth Antimony Tellurides

    SciTech Connect

    Zhang, Qian; Zhang, Qinyong; Chen, S.; Liu, W S; Lukas, K; Yan, X; Wang, H; Wang, D.; Opeil, C; Chen, Gang; Ren, Z. F.

    2011-01-01

    Grain growth is a major issue in the preparation of nanostructured bismuth-antimony-tellurides during hot pressing the nanopowders into dense bulk samples. To prevent grain agglomeration during ball milling and growth during hot pressing, organic agent (Oleic Acid, OA) as additive was added into the materials at the beginning of the ball milling process. With different concentrations of OA (0.5, 1.0, 1.5, 2.0, and 2.5 wt%), grains with different sizes are obtained. Structural analysis clearly shows that it is the particle size of the nanopowders that determines the final grain size in the densely compacted bulk samples. A combination of small grains ~200–500 nm and nanopores leads to effective phonon scattering, which results in the decrease of lattice thermal conductivity, and ZT of ~1.3 at 373 K for the sample with 2.0 wt% OA.

  15. Properties of antimony doped ZnO thin films deposited by spray pyrolysis technique

    SciTech Connect

    Sadananda Kumar, N. Bangera, Kasturi V.; Shivakumar, G. K.

    2015-07-15

    Antimony (Sb) doped zinc oxide (ZnO) thin films were deposited on the glass substrate at 450°C using spray pyrolysis technique. Effect of Sb doping on surface morphology structural, optical and electrical properties were studied. X-ray diffraction (XRD) analysis showed that both the undoped and doped ZnO thin films are polycrystalline in nature with (101) preferred orientation. SEM analysis showed a change in surface morphology of Sb doped ZnO thin films. Doping results in a marked increase in conductivity without affecting the transmittance of the films. ZnO films prepared with 3 at % Sb shows the lowest resistivity of 0.185 Ohm cm with a Hall mobility of 54.05 cm{sup 2} V{sup –1} s{sup –1}, and a hole concentration of 6.25 × 10{sup 17} cm{sup –3}.

  16. Image contrast mechanisms in dynamic friction force microscopy: Antimony particles on graphite

    NASA Astrophysics Data System (ADS)

    Mertens, Felix; Göddenhenrich, Thomas; Dietzel, Dirk; Schirmeisen, Andre

    2017-01-01

    Dynamic Friction Force Microscopy (DFFM) is a technique based on Atomic Force Microscopy (AFM) where resonance oscillations of the cantilever are excited by lateral actuation of the sample. During this process, the AFM tip in contact with the sample undergoes a complex movement which consists of alternating periods of sticking and sliding. Therefore, DFFM can give access to dynamic transition effects in friction that are not accessible by alternative techniques. Using antimony nanoparticles on graphite as a model system, we analyzed how combined influences of friction and topography can effect different experimental configurations of DFFM. Based on the experimental results, for example, contrast inversion between fractional resonance and band excitation imaging strategies to extract reliable tribological information from DFFM images are devised.

  17. Spectroscopic properties of Eu-doped antimony-germanate glass and glass-ceramics

    NASA Astrophysics Data System (ADS)

    Zmojda, J.; Kochanowicz, M.; Miluski, P.; Ragin, T.; Dorosz, D.; ZajÄ c, A.

    2016-09-01

    In our work we focused on possibility of obtaining phosphate nano-phase structures in antimony-germanate glasses doped with europium ions. The glasses with molar composition of 50(Sb2O3 - GeO2) - 50(SiO2 - Al2O3 - Na2O) doped with 0.5mol% Eu2O3 were prepared by standard melt-quenching method. In order to optimize glass-ceramic system the influence of phosphate concentration (up to 10mol%) on spectroscopic properties have been investigated. The symmetry nature of molecular structure around europium ions have been determined from the intensity ratio between (5D0 →7F2)/(5D0 →7F1) transitions. The effect of prominent Stark splitting of luminescence band at 612 nm characterised as "hypersensitive transition" into 3 sub-wavelength was observed in glasses with 1mol% and 3mol% of P2O5.

  18. First-Principles Study of Antimony Doping Effects on the Iron-Based Superconductor CaFe(SbxAs1-x)2

    NASA Astrophysics Data System (ADS)

    Nagai, Yuki; Nakamura, Hiroki; Machida, Masahiko; Kuroki, Kazuhiko

    2015-09-01

    We study antimony doping effects on the iron-based superconductor CaFe(SbxAs1-x)2 by using the first-principles calculation. The calculations reveal that the substitution of a doped antimony atom into As of the chainlike As layers is more stable than that into FeAs layers. This prediction can be checked by experiments. Our results suggest that doping homologous elements into the chainlike As layers, which only exist in the novel 112 system, is responsible for rising up the critical temperature. We discuss antimony doping effects on the electronic structure. It is found that the calculated band structures with and without the antimony doping are similar to each other within our framework.

  19. Food crop accumulation and bioavailability assessment for antimony (Sb) compared with arsenic (As) in contaminated soils.

    PubMed

    Wilson, Susan C; Tighe, Matthew; Paterson, Ewan; Ashley, Paul M

    2014-10-01

    Field samples and a 9-week glasshouse growth trial were used to investigate the accumulation of mining derived arsenic (As) and antimony (Sb) in vegetable crops growing on the Macleay River Floodplain in Northern New South Wales, Australia. The soils were also extracted using EDTA to assess the potential for this extractant to be used as a predictor of As and Sb uptake in vegetables, and a simplified bioaccessibility extraction test (SBET) to understand potential for uptake in the human gut with soil ingestion. Metalloids were not detected in any field vegetables sampled. Antimony was not detected in the growth trial vegetable crops over the 9-week greenhouse trial. Arsenic accumulation in edible vegetable parts was <10 % total soil-borne As with concentrations less than the current Australian maximum residue concentration for cereals. The results indicate that risk of exposure through short-term vegetable crops is low. The data also demonstrate that uptake pathways for Sb and As in the vegetables were different with uptake strongly impacted by soil properties. A fraction of soil-borne metalloid was soluble in the different soils resulting in Sb soil solution concentration (10.75 ± 0.52 μg L(-1)) that could present concern for contamination of water resources. EDTA proved a poor predictor of As and Sb phytoavailability. Oral bioaccessibility, as measured by SBET, was <7 % for total As and <3 % total Sb which is important to consider when estimating the real risk from soil borne As and Sb in the floodplain environment.

  20. Speciation of inorganic antimony (III & V) employing polyurethane foam loaded with bromopyrogallol red.

    PubMed

    Vinhal, Jonas O; Gonçalves, Aline D; Cruz, Graziela F B; Cassella, Ricardo J

    2016-04-01

    In this work, the speciation analysis of inorganic antimony (Sb(III) and Sb(V)) is proposed using polyurethane foam loaded with bromopyrogallol red (PUF-BPR) as a selective sorbent for Sb(III). The quantification of Sb in the solutions was performed by graphite furnace atomic absorption spectrometry (GF AAS), and several variables that could affect the performance of the method were carefully evaluated. The best conditions for the sorption of Sb(III) were achieved by shaking 50mg of PUF-BPR with the solutions containing Sb(III) at pH 4.0 for 90 min. In this condition, the retention of Sb(V) was not significant, whereas the removal of Sb(III) from the solution was higher than 95%. The desorption of Sb(III) from loaded PUF-BPR was possible by shaking the loaded foam with 7.5 mL of a 2.5 mol L(-1) HNO3 solution for 30 min. No interference of metal cations was observed on the solid-phase extraction of Sb(III) by PUF-BPR. The developed method was applied in the speciation analysis of antimony in river water samples fortified with different concentrations of Sb(III) and Sb(V). Also, we performed the determination of Sb(III) in a sample of a Sb-based drug utilized in the treatment of leishmaniasis. The results show that Sb(III) can be separated from high concentrations of Sb(V), since recoveries in the range of 81-110% were obtained in the analysis of the samples. The method presented limits of detection and quantification of 0.6 and 2 µg L(-1), respectively, for Sb(III) and 1 and 3 µg L(-1) for Sb(V), respectively.

  1. A New ABC Half-Transporter in Leishmania major Is Involved in Resistance to Antimony

    PubMed Central

    Manzano, J. I.; García-Hernández, R.; Castanys, S.

    2013-01-01

    The characterization of ABCI4, a new intracellular ATP-binding cassette (ABC) half-transporter in Leishmania major, is described. We show that ABCI4 is involved in heavy metal export, thereby conferring resistance to Pentostam, to Sb(III), and to As(III) and Cd(II). Parasites overexpressing ABCI4 showed a lower mitochondrial toxic effect of antimony by decreasing reactive oxygen species production and maintained higher values of both the mitochondrial electrochemical potential and total ATP levels with respect to controls. The ABCI4 half-transporter forms homodimers as determined by a coimmunoprecipitation assay. A combination of subcellular localization studies under a confocal microscope and a surface biotinylation assay using parasites expressing green fluorescent protein- and FLAG-tagged ABCI4 suggests that the transporter presents a dual localization in both mitochondria and the plasma membrane. Parasites overexpressing ABCI4 present an increased replication in mouse peritoneal macrophages. We have determined that porphyrins are substrates for ABCI4. Consequently, the overexpression of ABCI4 confers resistance to some toxic porphyrins, such as zinc-protoporphyrin, due to the lower accumulation resulting from a significant efflux, as determined using the fluorescent zinc-mesoporphyrin, a validated heme analog. In addition, ABCI4 has a significant ability to efflux thiol after Sb(III) incubation, thus meaning that ABCI4 could be considered to be a potential thiol-X-pump that is able to recognize metal-conjugated thiols. In summary, we have shown that this new ABC transporter is involved in drug sensitivity to antimony and other compounds by efflux as conjugated thiol complexes. PMID:23716044

  2. The effect of phosphate application on the mobility of antimony in firing range soils.

    PubMed

    Griggs, Christopher S; Martin, W Andy; Larson, Steven L; O'Connnor, Greg; Fabian, Gene; Zynda, Greg; Mackie, David

    2011-05-15

    Chemical and biogenic sources of phosphate are commonly accepted in situ treatment methods for immobilization of lead (Pb) in soil. The metalloid antimony (Sb), commonly associated with Pb in the environment, exists as either a neutral species or a negatively charged oxyanion. Antimony is used in the manufacture of bullets as a hardening agent, constituting approximately 3% of the bullet mass. Technological solutions to reduce the migration of metals from small arms firing range (SAFR) soils for environmental compliance purposes must be robust with respect to multi-component systems containing both cationic and anionic contaminants. The effect of varying physico-chemical soil properties on Sb mobility post-firing was assessed in this study for six soil types using common analytical protocols and methods related to regulatory criteria. The sands (SM and SP) demonstrated the greatest Sb solubility in post-firing leachate samples and therefore were selected to evaluate the effects of five commercially available stabilization amendments on Sb mobility. Enhanced Sb leaching was experimentally confirmed in the phosphate-treated soils compared to both the untreated control soil and the sulfur-based amendment, and thus suggests competition for negative sorption sites between Sb and phosphate. However, the 5% Buffer Block® calcium phosphate amendment did not exhibit the same enhanced Sb release. This can be attributed to the inclusion of aluminum hydroxide in the amendment composition. Technologies are needed that will adequately immobilize Pb without mobilizing oxyanions such as Sb. Further research will be required to elucidate binding mechanisms and redox conditions that govern the mobility of Sb on SAFRs.

  3. Fatty acid profiles in Leishmania spp. isolates with natural resistance to nitric oxide and trivalent antimony.

    PubMed

    de Azevedo, Alana Freire; Dutra, Jorge Luís de Lisboa; Santos, Micheli Luize Barbosa; Santos, Darlisson de Alexandria; Alves, Péricles Barreto; de Moura, Tatiana Rodrigues; de Almeida, Roque Pacheco; Fernandes, Marcelo Ferreira; Scher, Ricardo; Fernandes, Roberta Pereira Miranda

    2014-01-01

    Fatty acids, especially those from phospholipids (PLFA), are essential membrane components that are present in relatively constant proportions in biological membranes under natural conditions. However, under harmful growth conditions, such as diseases, environmental changes, and chemical exposure, the fatty acid proportions might vary. If such changes could be identified and revealed to be specific for adverse situations, they could be used as biomarkers. Such biomarkers could facilitate the identification of virulence and resistance mechanisms to particular chemotherapeutic agents. Therefore, specific biomarkers could lead to better therapeutic decisions that would, in turn, enhance treatment effectiveness. The objective of this study was to compare the fatty acid profiles of trivalent antimony and nitric oxide (NO)-resistant and -sensitive Leishmania chagasi and Leishmania amazonensis isolates. Fatty acid methyl esters (FAMEs) were obtained from total lipids (MIDI), ester-linked lipids (ELFA), and ester-linked phospholipids (PLFA). FAMEs were analyzed by chromatography and mass spectrometry. Species- or resistance-associated differences in FAME profiles were assessed by nonmetric multidimensional scaling, multiresponse permutation procedures, and indicator species analyses. The isolate groups had different MIDI-FAME profiles. However, neither the ELFA nor PLFA profiles differed between the sensitive and resistant isolates. Levels of the fatty acid 18:1 Δ9c were increased in sensitive isolates (p < 0,001), whereas the fatty acid 20:4 Δ5,8,11,14 showed the opposite trend (p < 0.01). We conclude that these two fatty acids are potential biomarkers for NO and antimony resistance in L. chagasi and L. amazonensis and that they could be helpful in therapeutic diagnoses.

  4. The origin and behavior of lead, cadmium and antimony in MSW incinerator

    SciTech Connect

    Nakamura, Kazuo; Kinoshita, Sayuri; Takatsuki, Hiroshi

    1996-12-31

    The Amendment to the Waste Disposal and Public Cleansing Law in Japan has introduced new regulation of waste requiring strict management. In this regulation, the fly ash generated in the Municipal Solid Waste (MSW) incinerator process was designated as specially controlled solid waste because of relatively high concentrations of lead and cadmium. Furthermore, antimony is a regulated constituent within the Basel Convention on the control of transboundary movements of hazardous wastes and their disposal and was designated a monitor item of environmental standards on water pollution. Thus, in order to understand where the problems lie, the behaviors of these heavy metals in the MSW incinerator was investigated. Also investigated were the kinds of products causing the fly ash to be contaminated. As a result, the amount of lead, cadmium and antimony in household waste was about 120, 3.5 and 7.6 g/T, respectively. The major origins of Pb, Cd and Sb from household waste are small sealed lead batteries, nickel-cadmium batteries and flame-proofed products such as curtains and plastic covers. By incineration treatment, these metals shifted to the fly ash (EP ash); the transfer ratio of Pb, Cd and Sb was about 33, 92 and 45%, respectively. The observed results indicated that the partitioning of metals in the MSW incinerator showed the influence of the vapor pressure of the elements and their compounds. Clearly, to produce precise estimates of this behavior, it will be necessary to determine not only the concentration of the elements in the waste but also the compounds used and the changes these would undergo in the furnace. Finally, several measures which will be helpful in solving these problems are introduced to discuss the future direction of environmentally-friendly social systems.

  5. Annealing of aromatic polyimide precursors

    NASA Technical Reports Server (NTRS)

    Wakelyn, N. T.

    1975-01-01

    A study has been made of the thermal behavior of polyimide precursors: an isomeric pair of crystals of the complex formed by p-phenylenediamine with the separated isomers of the di-isopropyl ester of pyromellitic acid. Specimens of this material were isothermally annealed in the temperature range 120 C to 170 C for periods of time up to 1 week. Although this temperature range is well below that customarily used for imidizations, the working hypothesis was that it would be more likely that a polymer embodying at least part of the precursor structure could be formed if the molecular motion was minimized to that actually required for the formation of the imide linkage. The progress of the annealing was followed by: infrared spectroscopy, differential thermal analysis, powder X-ray diffraction, and thermal gravimetric analysis. Single crystal X-ray analysis of the meta monomer yields a structure of chains of alternating acid and base and suggests that this monomer is amenable to polymerization with a minimum of geometrical disruption.

  6. Simultaneous spectrophotometric determination of copper, cobalt, nickel and iron in foodstuffs and vegetables with a new bis thiosemicarbazone ligand using chemometric approaches.

    PubMed

    Rohani Moghadam, Masoud; Poorakbarian Jahromi, Sayedeh Maria; Darehkordi, Ali

    2016-02-01

    A newly synthesized bis thiosemicarbazone ligand, (2Z,2'Z)-2,2'-((4S,5R)-4,5,6-trihydroxyhexane-1,2-diylidene)bis(N-phenylhydrazinecarbothioamide), was used to make a complex with Cu(2+), Ni(2+), Co(2+) and Fe(3+) for their simultaneous spectrophotometric determination using chemometric methods. By Job's method, the ratio of metal to ligand in Ni(2+) was found to be 1:2, whereas it was 1:4 for the others. The effect of pH on the sensitivity and selectivity of the formed complexes was studied according to the net analyte signal (NAS). Under optimum conditions, the calibration graphs were linear in the ranges of 0.10-3.83, 0.20-3.83, 0.23-5.23 and 0.32-8.12 mg L(-1) with the detection limits of 2, 3, 4 and 10 μg L(-1) for Cu(2+), Co(2+), Ni(2+) and Fe(3+) respectively. The OSC-PLS1 for Cu(2+) and Ni(2+), the PLS1 for Co(2+) and the PC-FFANN for Fe(3+) were selected as the best models. The selected models were successfully applied for the simultaneous determination of elements in some foodstuffs and vegetables.

  7. Crystal structures of copper(II) chloride, copper(II) bromide, and copper(II) nitrate complexes with pyridine-2-carbaldehyde thiosemicarbazone

    SciTech Connect

    Chumakov, Yu. M.; Tsapkov, V. I.; Jeanneau, E.; Bairac, N. N.; Bocelli, G.; Poirier, D.; Roy, J.; Gulea, A. P.

    2008-09-15

    The crystal structures of chloro-(2-formylpyridinethiosemicarbazono)copper dimethyl sulfoxide solvate (I), bromo-(2-formylpyridinethiosemicarbazono)copper (II), and (2-formylpyridinethiosemicarbazono)copper(II) nitrate dimethyl sulfoxide solvate (III) are determined using X-ray diffraction. In the crystals, complexes I and II form centrosymmetric dimers in which the thiosemicarbazone sulfur atom serves as a bridge and occupies the fifth coordination site of the copper atom of the neighboring complex related to the initial complex through the center of symmetry. In both cases, the coordination polyhedron of the complexing ion is a distorted tetragonal bipyramid. Complex III in the crystal structure forms polymer chains in which the copper atom of one complex forms the coordination bond with the thicarbamide nitrogen atom of the neighboring complex. In this structure, the coordination polyhedron of the central atom is an elongated tetragonal bipyramid. It is established that complexes I-III at a concentration of 10{sup -5} mol/l selectively inhibit the growth of 60 to 90 percent of the cancer tumor cells of the human myeloid leukemia (HL-60).

  8. Evaluation of DNA-binding, DNA cleavage, antioxidant and cytotoxic activity of mononuclear ruthenium(II) carbonyl complexes of benzaldehyde 4-phenyl-3-thiosemicarbazones

    NASA Astrophysics Data System (ADS)

    Sampath, Krishnan; Sathiyaraj, Subbaiyan; Jayabalakrishnan, Chinnasamy

    2013-11-01

    Two 4-phenyl-3-thiosemicarbazone ligands, (E)-2-(2-chlorobenzylidene)-N-phenylhydrazinecarbothioamide (HL1) and (E)-2-(2-nitrobenzylidene)-N-phenylhydrazinecarbothioamide (HL2), and its ruthenium(II) complexes were synthesized and characterized by physico-chemical and spectroscopic methods. The Schiff bases act as bidentate, monobasic chelating ligands with S and N as the donor sites and are preferably found in the thiol form in all the complexes studied. The molecular structure of HL1 and HL2 were determined by single crystal X-ray diffraction method. DNA binding of the compounds was investigated by absorption spectroscopy which indicated that the compounds bind to DNA via intercalation. The oxidative cleavage of the complexes with CT-DNA inferred that the effects of cleavage are dose dependent. Antioxidant study of the ligands and complexes showed significant antioxidant activity against DPPH radical. In addition, the in vitro cytotoxicity of the ligands and complexes assayed against HeLa and MCF-7 cell lines showed higher cytotoxic activity with the lower IC50 values indicating their efficiency in killing the cancer cells even at low concentrations.

  9. Highly efficient ultrasonic-assisted removal of Hg(II) ions on graphene oxide modified with 2-pyridinecarboxaldehyde thiosemicarbazone: Adsorption isotherms and kinetics studies.

    PubMed

    Tadjarodi, Azadeh; Moazen Ferdowsi, Somayeh; Zare-Dorabei, Rouholah; Barzin, Ahmad

    2016-11-01

    A novel adsorbent, based on modifying graphene oxide (GO) chemically with 2-pyridinecarboxaldehyde thiosemicarbazone (2-PTSC) as ligand, was designed by facile process for removal of Hg(II) from aqueous solution. Characterization of the adsorbent was performed using various techniques, such as FT-IR, XRD, XPS, SEM and AFM analysis. The adsorption capacity was affected by variables such as adsorbent dosage, pH solution, Hg(2+) initial concentration and sonicating time. These variables were optimized by rotatable central composite design (CCD) under response surface methodology (RSM). The predictive model for Hg(II) adsorption was constructed and applied to find the best conditions at which the responses were maximized. In this conditions, the adsorption capacity of this adsorbent for Hg(2+) ions was calculated to be 309mgg(-1) that was higher than that of GO. Appling the ultrasound power combined with adsorption method was very efficient in shortening the removal time of Hg(2+) ions by enhancing the dispersion of adsorbent and metal ions in solution and effective interactions among them. The adsorption process was well described by second-order kinetic and Langmuir isotherm model in which the maximum adsorption capacity (Qm) was found to be 555mgg(-1) for adsorption of Hg(2+) ions over the obtained adsorbent. The performance of adsorbent was examined on the real wastewaters and confirmed the applicability of adsorbent for practical applications.

  10. DNA, protein binding, cytotoxicity, cellular uptake and antibacterial activities of new palladium(II) complexes of thiosemicarbazone ligands: effects of substitution on biological activity.

    PubMed

    Kalaivani, P; Prabhakaran, R; Dallemer, F; Poornima, P; Vaishnavi, E; Ramachandran, E; Padma, V Vijaya; Renganathan, R; Natarajan, K

    2012-01-01

    The coordination propensities of 4(N,N')-diethylaminosalicylaldehyde-4(N)-substituted thiosemicarbazones (H(2)L(1-4)) were investigated by reacting with an equimolar amount of [PdCl(2)(PPh(3))(2)]. The new complexes were characterized by various spectroscopic techniques. The structure determination of the complexes [Pd(DeaSal-tsc)(PPh(3))] (1), [Pd(DeaSal-mtsc)(PPh(3))] (2) and [Pd(DeaSal-etsc)(PPh(3))] (3) by X-ray crystallography showed that ligands are coordinated in a dibasic tridentate ONS donor fashion forming stable five and six membered chelate rings. The binding ability of complexes (1-4) to calf-thymus DNA (CT DNA) has been explored by absorption and emission titration methods. Based on the observations, an electrostatic and an intercalative binding mode have been proposed. The protein binding studies have been monitored by quenching of tryptophan and tyrosine residues in the presence of complexes using lysozyme as a model protein. As determined by MTT assays, complex 3 exhibited a higher cytotoxic effect towards human lung cancer cell line (A549) and liver cancer cells (HepG2). LDH, NO assay and cellular uptake of the complexes have been studied. Further, antibacterial activity studies of the complexes have been screened against the pathogenic bacteria such as Enterococcus faecalis, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa, MIC50 values of the complexes showed that the complexes exhibited significant activity against the pathogens and among the complexes, 3 exhibited higher activity.

  11. Spectroscopic characterization, antioxidant and antitumour studies of novel bromo substituted thiosemicarbazone and its copper(II), nickel(II) and palladium(II) complexes

    NASA Astrophysics Data System (ADS)

    Jagadeesh, M.; Lavanya, M.; Kalangi, Suresh K.; Sarala, Y.; Ramachandraiah, C.; Varada Reddy, A.

    2015-01-01

    A new, slightly distorted octahedral complex of copper(II), square planar complexes of nickel(II) and palladium(II) with 2,4‧-dibromoacetophenone thiosemicarbazone (DBAPTSC) are synthesized. The ligand and the complexes are characterized by FT-IR, FT-Raman, powder X-ray diffraction studies. The IR and Raman data are correlated for the presence of the functional groups which specifically helped in the confirmation of the compounds. In addition, the free ligand is unambiguously characterized by 1H and 13C NMR spectroscopy while the copper(II) complex is characterized by electron paramagnetic resonance spectroscopy (EPR). The g values for the same are found to be 2.246 (g1), 2.012 (g2) and 2.005 (g3) which suggested rhombic distortions. The HOMO-LUMO band gap calculations for these compounds are found to be in between 0.5 and 4.0 eV and these compounds are identified as semiconducting materials. The synthesized ligand and its copper(II), nickel(II) and palladium(II) complexes are subjected to antitumour activity against the HepG2 human hepatoblastoma cell lines. Among all the compounds, nickel(II) complex is found to exert better antitumour activity with 57.6% of cytotoxicity.

  12. Computational study of the vibrational spectroscopic studies, natural bond orbital, frontier molecular orbital and second-order non-linear optical properties of acetophenone thiosemicarbazone molecule.

    PubMed

    Li, Xiao-Hong; Mei, Zheng; Zhang, Xian-Zhou

    2014-01-24

    The vibrational frequencies of acetophenone thiosemicarbazone in the ground state have been calculated using density functional method (B3LYP) with 6-31G(d), 6-31G(d,p) and 6-311++G(d,p) basis sets. The analysis of natural bond orbital was also performed. The IR spectra were obtained and interpreted by means of potential energies distributions (PEDs) using MOLVIB program. In addition, the results show that there exist N-H…N and N-H…S hydrogen bonds in the title compound, which play a major role in stabilizing the molecule and are confirmed by the natural bond orbital analysis. The predicted NLO properties show that the title compound is a good candidate as second-order NLO material. In addition, the frontier molecular orbitals were analyzed and the crystal structure obtained by molecular mechanics belongs to the Pbca space group, with lattice parameters Z=8, a=16.0735 Å, b=7.1719 Å, c=7.8725 Å, ρ=0.808 g/cm(3).

  13. Simultaneous Determination of Cobalt(II) and Nickel(II) by Fourth-Order Derivative Spectrophotometric Method Using 2-Hydroxy-3-Methoxy Benzaldehyde Thiosemicarbazone

    PubMed Central

    Kumar, A. Praveen; Reddy, P. Raveendra; Reddy, V. Krishna

    2007-01-01

    A simple and new simultaneous fourth derivative spectrophotometric method is proposed for the analysis of a two-component system containing cobalt(II) and nickel(II) without separation using 2-hydroxy-3-methoxy benzaldehyde thiosemicarbazone (HMBATSC) as a chromophoric reagent. The reagent reacts with cobalt(II) and nickel(II) at pH 6.0, forming soluble brown and yellow colored species, respectively. Cobalt(II) and nickel(II) present in themixture are simultaneously determined without solving the simultaneous equations bymeasuring the fourth derivative amplitudes at 468.5 nm and 474.5 nm, respectively. The derivative amplitudes obey Beer's law at 468.5 nm and 474.5 nm for Co(II) and Ni(II) in the range 0.059–3.299 μg mL−1 and 0.058–3.285 μg mL−1 respectively. A large number of foreign ions do not interfere in the present method. The present simultaneous method is used for the determination of micro amounts of cobalt in biological samples, nickel in plant samples, and in some alloy steels and soil sample. PMID:17671609

  14. Synthesis of a DNA-targeting nickel (II) complex with testosterone thiosemicarbazone which exhibits selective cytotoxicity towards human prostate cancer cells (LNCaP).

    PubMed

    Heng, Mok Piew; Sinniah, Saravana Kumar; Teoh, Wuen Yew; Sim, Kae Shin; Ng, Seik Weng; Cheah, Yoke Kqueen; Tan, Kong Wai

    2015-01-01

    Testosterone thiosemicarbazone, L and its nickel (II) complex 1 were synthesized and characterized by using FTIR, CHN, (1)H NMR, and X-ray crystallography. X-ray diffraction study confirmed the formation of L from condensation of testosterone and thiosemicarbazide. Mononuclear complex 1 is coordinated to two Schiff base ligands via two imine nitrogens and two tautomeric thiol sulfurs. The cytotoxicity of both compounds was investigated via MTT assay with cisplatin as positive reference standard. L is more potent towards androgen-dependent LNCaP (prostate) and HCT 116 (colon). On the other hand, complex 1, which is in a distorted square planar environment with L acting as a bidentate NS-donor ligand, is capable of inhibiting the growth of all the cancer cell lines tested, including PC-3 (prostate). It is noteworthy that both compounds are less toxic towards human colon cell CCD-18Co. The intrinsic DNA binding constant (Kb) of both compounds were evaluated via UV-Vis spectrophotometry. Both compounds showed Kb values which are comparable to the reported Kb value of typical classical intercalator such as ethidium bromide. The binding constant of the complex is almost double compared with ligand L. Both compounds were unable to inhibit the action topoisomerase I, which is the common target in cancer treatment (especially colon cancer). This suggest a topoisomerase I independent-cell death mechanism.

  15. Thiosemicarbazone p-Substituted Acetophenone Derivatives Promote the Loss of Mitochondrial Δψ, GSH Depletion, and Death in K562 Cells

    PubMed Central

    Pessoto, Felipe S.; Yokomizo, Cesar H.; Prieto, Tatiana; Fernandes, Cleverton S.; Silva, Alan P.; Kaiser, Carlos R.; Basso, Ernani A.; Nantes, Iseli L.

    2015-01-01

    A series of thiosemicarbazone (TSC) p-substituted acetophenone derivatives were synthesized and chemically characterized. The p-substituents appended to the phenyl group of the TSC structures were hydrogen, fluor, chlorine, methyl, and nitro, producing compounds named TSC-H, TSC-F, TSC-Cl, TSC-Me, and TSC-NO2, respectively. The TSC compounds were evaluated for their capacity to induce mitochondrial permeability, to deplete mitochondrial thiol content, and to promote cell death in the K562 cell lineage using flow cytometry and fluorescence microscopy. TSC-H, TSC-F, and TSC-Cl exhibited a bell-shaped dose-response curve for the induction of apoptosis in K562 cells due to the change from apoptosis to necrosis as the principal mechanism of cell death at the highest tested doses. TSC-Me and TSC-NO2 exhibited a typical dose-response profile, with a half maximal effective concentration of approximately 10 µM for cell death. Cell death was also evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, which revealed lower toxicity of these compounds for peripheral blood mononuclear cells than for K562 cells. The possible mechanisms leading to cell death are discussed based on the observed effects of the new TSC compounds on the cellular thiol content and on mitochondrial bioenergetics. PMID:26075034

  16. Synthesis, spectral characterization and biological activities of Mn(II) and Co(II) complexes with benzyloxybenzaldehyde-4-phenyl-3-thiosemicarbazone.

    PubMed

    Prathima, B; Rao, Y Subba; Ramesh, G N; Jagadeesh, M; Reddy, Y P; Chalapathi, P V; Reddy, A Varada

    2011-06-01

    Mn(II) and Co(II) complexes of benzyloxybenzaldehyde-4-phenyl-3-thiosemicarbazone have been synthesized and characterized by the investigations of electronic and EPR spectra and X-ray diffraction. Based on the spectral studies, an octahedral geometry is assigned for the Mn(II) and Co(II) complexes. X-ray powder diffraction studies reveal that Mn(II) and Co(II) complexes have triclinic crystal lattices. The unit cell parameters of the Mn(II) complex are a=11.0469 Å, b=6.2096 Å, c=7.4145 Å, α=90.646°, β=95.127°, γ=104.776°, V=489.7 Å(3) and those of Co(II) complex are a=9.3236 Å, b=10.2410 Å, c=7.8326 Å, α=90.694°, β=99.694°, γ=100.476°, V=724.2 Å(3). When the free ligand and its metal complexes are subjected to antibacterial activity, the metal complexes are proved to be more active than the ligand. However with regard to in vitro antioxidant activity, the ligand exhibits greater antioxidant activity than its metal(II) complexes.

  17. Spectroscopic (FT-IR, FT-Raman) and quantum mechanical studies of 3t-pentyl-2r,6c-diphenylpiperidin-4-one thiosemicarbazone.

    PubMed

    Savithiri, S; Arockia doss, M; Rajarajan, G; Thanikachalam, V; Bharanidharan, S; Saleem, H

    2015-02-05

    In this study, the molecular structure and vibrational spectra of 3t-pentyl2r,6c-diphenylpiperidin-4-one thiosemicarbazone (PDPOTSC) were studied. The ground-state molecular geometry was ascertained by using the density functional theory (DFT)/B3LYP method using 6-31++G(d,p) as a basis set. The vibrational (FT-IR and FT-Raman) spectra of PDPOTSC were computed using DFT/B3LYP and HF methods with 6-31++G(d,p) basis set. The fundamental vibrations were assigned on the basis of the total energy distribution (TED⩾10%) of the vibrational modes, calculated with scaled quantum mechanics (SQM) methods PQS program. The electrical dipole moment (μ) and first hyperpolarizability (βo) values have been computed using DFT/B3LYP and HF methods. The calculated result (βo) shows that the title molecule might have nonlinear optical (NLO) behavior. Atomic charges of C, N, S and molecular electrostatic potential (MEP) were calculated using B3LYP/6-31G++(d,p). The HOMO-LUMO energies were calculated and natural bonding orbital (NBO) analysis has also been carried out.

  18. Spectroscopic (FT-IR, FT-Raman) and quantum mechanical studies of 3t-pentyl-2r,6c-diphenylpiperidin-4-one thiosemicarbazone

    NASA Astrophysics Data System (ADS)

    Savithiri, S.; Arockia doss, M.; Rajarajan, G.; Thanikachalam, V.; Bharanidharan, S.; Saleem, H.

    2015-02-01

    In this study, the molecular structure and vibrational spectra of 3t-pentyl2r,6c-diphenylpiperidin-4-one thiosemicarbazone (PDPOTSC) were studied. The ground-state molecular geometry was ascertained by using the density functional theory (DFT)/B3LYP method using 6-31++G(d,p) as a basis set. The vibrational (FT-IR and FT-Raman) spectra of PDPOTSC were computed using DFT/B3LYP and HF methods with 6-31++G(d,p) basis set. The fundamental vibrations were assigned on the basis of the total energy distribution (TED ⩾ 10%) of the vibrational modes, calculated with scaled quantum mechanics (SQM) methods PQS program. The electrical dipole moment (μ) and first hyperpolarizability (βo) values have been computed using DFT/B3LYP and HF methods. The calculated result (βo) shows that the title molecule might have nonlinear optical (NLO) behavior. Atomic charges of C, N, S and molecular electrostatic potential (MEP) were calculated using B3LYP/6-31G++(d,p). The HOMO-LUMO energies were calculated and natural bonding orbital (NBO) analysis has also been carried out.

  19. DNA binding, antioxidant, cytotoxicity (MTT, lactate dehydrogenase, NO), and cellular uptake studies of structurally different nickel(II) thiosemicarbazone complexes: synthesis, spectroscopy, electrochemistry, and X-ray crystallography.

    PubMed

    Prabhakaran, R; Kalaivani, P; Huang, R; Poornima, P; Vijaya Padma, V; Dallemer, F; Natarajan, K

    2013-02-01

    Three new nickel(II) thiosemicarbazone complexes have been synthesized and characterized by analytical, spectral, and single-crystal X-ray diffraction studies. In complex 1, the ligand 2-hydroxy-1-naphthaldehydethiosemicarbazone coordinated as a monobasic tridentate donor, whereas in complexes 2 and 3, the ligands salicylaldehyde-4(N)-ethylthiosemicarbazone and 2-hydroxy-1-naphthaldehyde-4(N)-ethylthiosemicarbazone coordinated as a dibasic tridentate donor. The DNA binding ability of the complexes in calf thymus DNA was explored by absorption and emission titration experiments. The antioxidant property of the new complexes was evaluated to test their free-radical scavenging ability. In vitro cytotoxicity assays were performed for the new complexes in A549 and HepG2 cell lines. The new compounds overcome cisplatin resistance in the A549 cell line and they were also active in the HepG2 cell line. The cellular uptake study showed the accumulation of the complexes in tumor cells depended on the nature of the ligand attached to the nickel ion.

  20. Novel Thiosemicarbazones Inhibit Lysine-Rich CEACAM1 Co-isolated (LYRIC) and the LYRIC-Induced Epithelial-Mesenchymal Transition via Up-Regulation of N-Myc Downstream-Regulated Gene 1 (NDRG1).

    PubMed

    Xi, Ruxing; Pun, Ivan Ho Yuen; Menezes, Sharleen V; Fouani, Leyla; Kalinowski, Danuta S; Huang, Michael L H; Zhang, Xiaozhi; Richardson, Des R; Kovacevic, Zaklina

    2017-03-08

    Tumor necrosis factor α (TNFα) plays a vital role in cancer progression, being associated with inflammation and promotion of cancer angiogenesis and metastasis. The effects of TNFα are mediated by its down-stream target, the oncogene, lysine-rich CEACAM1 co-isolated protein (LYRIC; also known as metadherin or astrocyte elevated gene-1). LYRIC plays an important role in activating the nuclear factor-κB (NF-κB) signaling pathway, which controls multiple cellular processes, including proliferation, apoptosis, migration, etc. In contrast, the metastasis suppressor, N-myc down-stream regulated gene 1 (NDRG1), has the opposite effect on the NF-κB pathway, being able to inhibit NF-κB activation and reduce angiogenesis, proliferation, migration and cancer cell invasion. These potent anti-cancer properties make NDRG1 an ideal therapeutic target. Indeed, a novel class of thiosemicarbazone anti-cancer agents that target this molecule have been developed, with the lead agent, di-2-pyridylketone 4-cyclohexyl-4-methyl-3-thiosemicarbazone (DpC), recently entering clinical trials for advanced and resistant cancers. To further elucidate the interaction between NDRG1 and oncogenic signaling, this study for the first time assessed the effects of NDRG1 on the tumorigenic properties of TNFα and its down-stream target, LYRIC. We demonstrate that NDRG1 inhibits the TNFα-mediated epithelial to mesenchymal transition (EMT). Further, NDRG1 also potently inhibited LYRIC expression, with a negative feedback loop existing between these two molecules. Examining the mechanism involved, we demonstrated that NDRG1 inhibited PI3K/AKT signaling, leading to reduced levels of the LYRIC transcriptional activator, c-Myc. Finally, we demonstrate that novel thiosemicarbazones that up-regulate NDRG1 also inhibit LYRIC expression, further highlighting their marked potential for cancer treatment.

  1. Halo-substituted thiosemicarbazones and their copper(II), nickel(II) complexes: detailed spectroscopic characterization and study of antitumour activity against HepG2 human hepatoblastoma cells.

    PubMed

    Jagadeesh, M; Kalangi, Suresh K; Sivarama Krishna, L; Reddy, A Varada

    2014-01-24

    Copper(II) and nickel(II) complexes of two different halogen substituted thiosemicarbazone ligands were synthesized. The ligands 3,4-difluoroacetophenone thiosemicarbazone (1) and 2-bromo-4'-chloroacetophenone thiosemicarbazone (2) were characterized and confirmed spectroscopically by FT-IR, FT-Raman, UV-vis and fluorescence spectral analysis, while the respective copper(II) complexes [Cu(C9H9N3F2S)2Cl2] (1a), [Cu(C9H9N3ClBrS)2Cl2] (2a) and nickel(II) complexes [Ni(C9H9N3F2S)2] (1b), [Ni(C9H9N3ClBrS)2] (2b) were characterized by FT-IR, UV-vis and electron paramagnetic spectroscopy (EPR). The EPR spectra of the Cu(II) complexes provided the rhombic octahedral and axial symmetry of the complexes 1a and 2a respectively. For the complex 1a, the g values calculated as g1=2.1228, g2=2.0706 and g3=2.001 between 2900 and 3300 G. While for the complex 2a, a set of two resonance absorptions were observed. The synthesized compounds were tested for antitumor activity and showed that the ability to kill liver cancer cells significantly. Out of all the synthesized compounds, copper(II) complexes 1a and 2a showed high cytotoxic effect on liver cancer cells with 67.51% and 42.77% of cytotoxicity respectively at 100 μM.

  2. Halo-substituted thiosemicarbazones and their copper(II), nickel(II) complexes: Detailed spectroscopic characterization and study of antitumour activity against HepG2 human hepatoblastoma cells

    NASA Astrophysics Data System (ADS)

    Jagadeesh, M.; Kalangi, Suresh K.; Sivarama Krishna, L.; Reddy, A. Varada

    2014-01-01

    Copper(II) and nickel(II) complexes of two different halogen substituted thiosemicarbazone ligands were synthesized. The ligands 3,4-difluoroacetophenone thiosemicarbazone (1) and 2-bromo-4'-chloroacetophenone thiosemicarbazone (2) were characterized and confirmed spectroscopically by FT-IR, FT-Raman, UV-vis and fluorescence spectral analysis, while the respective copper(II) complexes [Cu(C9H9N3F2S)2Cl2] (1a), [Cu(C9H9N3ClBrS)2Cl2] (2a) and nickel(II) complexes [Ni(C9H9N3F2S)2] (1b), [Ni(C9H9N3ClBrS)2] (2b) were characterized by FT-IR, UV-vis and electron paramagnetic spectroscopy (EPR). The EPR spectra of the Cu(II) complexes provided the rhombic octahedral and axial symmetry of the complexes 1a and 2a respectively. For the complex 1a, the g values calculated as g1 = 2.1228, g2 = 2.0706 and g3 = 2.001 between 2900 and 3300 G. While for the complex 2a, a set of two resonance absorptions were observed. The synthesized compounds were tested for antitumor activity and showed that the ability to kill liver cancer cells significantly. Out of all the synthesized compounds, copper(II) complexes 1a and 2a showed high cytotoxic effect on liver cancer cells with 67.51% and 42.77% of cytotoxicity respectively at 100 μM.

  3. Molecular and polymeric ceramic precursors

    SciTech Connect

    Sneddon, L.G.

    1991-08-01

    The development of new methods for the production of complex materials is one of the most important problems in modern solid state chemistry and materials science. This project is attempting to apply the synthetic principles which have evolved inorganic and organometallic chemistry to the production of technologically important non-oxide ceramics, such as boron nitride, boron carbide and metal borides. Our recent work has now resulted in the production of new polymer systems, including poly(B-vinylborazine), polyvinylpentaborane and polyborazylene, that have proven to be high yield precursors to boron-based ceramic materials. Current work is now directed toward the synthesis of new types of molecular and polymeric boron-containing species and on exploration of the solid state properties of the ceramics that have been produced in these studies.

  4. Determination of Antimony (III) in Real Samples by Anodic Stripping Voltammetry Using a Mercury Film Screen-Printed Electrode.

    PubMed

    Domínguez-Renedo, Olga; Gómez González, M Jesús; Arcos-Martínez, M Julia

    2009-01-01

    This paper describes a procedure for the determination of antimony (III) by differential pulse anodic stripping voltammetry using a mercury film screen-printed electrode as the working electrode. The procedure has been optimized using experimental design methodology. Under these conditions, in terms of Residual Standard Deviation (RSD), the repeatability (3.81 %) and the reproducibility (5.07 %) of the constructed electrodes were both analyzed. The detection limit for Sb (III) was calculated at a value of 1.27×10(-8) M. The linear range obtained was between 0.99 × 10(-8) - 8.26 × 10(-8) M. An analysis of possible effects due to the presence of foreign ions in the solution was performed and the procedure was successfully applied to the determination of antimony levels in pharmaceutical preparations and sea water samples.

  5. Cyanide and antimony thermodynamic database for the aqueous species and solids for the EPA-MINTEQ geochemical code

    SciTech Connect

    Sehmel, G.A.

    1989-05-01

    Thermodynamic data for aqueous species and solids that contain cyanide and antimony were tabulated from several commonly accepted, published sources of thermodynamic data and recent journal article. The review does not include gases or organic complexes of either antimony or cyanide, nor does the review include the sulfur compounds of cyanide. The basic thermodynamic data, ..delta..G/sub f,298//sup o/, ..delta..H/sub f,298//sup o/, and S/sub f//sup o/ values, were chosen to represent each solid phase and aqueous species for which data were available in the appropriate standard state. From these data the equilibrium constants (log K/sub r,298//sup o/) and enthalpies of reaction (..delta..H/sub r,298//sup o/) at 298 K (25/degree/C) were calculated for reactions involving the formation of these aqueous species and solids from the basic components. 34 refs., 14 tabs.

  6. Determination of Antimony (III) in Real Samples by Anodic Stripping Voltammetry Using a Mercury Film Screen-Printed Electrode

    PubMed Central

    Domínguez-Renedo, Olga; Gómez González, M. Jesús; Arcos-Martínez, M. Julia

    2009-01-01

    This paper describes a procedure for the determination of antimony (III) by differential pulse anodic stripping voltammetry using a mercury film screen-printed electrode as the working electrode. The procedure has been optimized using experimental design methodology. Under these conditions, in terms of Residual Standard Deviation (RSD), the repeatability (3.81 %) and the reproducibility (5.07 %) of the constructed electrodes were both analyzed. The detection limit for Sb (III) was calculated at a value of 1.27×10−8 M. The linear range obtained was between 0.99 × 10−8 − 8.26 × 10−8 M. An analysis of possible effects due to the presence of foreign ions in the solution was performed and the procedure was successfully applied to the determination of antimony levels in pharmaceutical preparations and sea water samples. PMID:22389596

  7. Co-administration of glycyrrhizic acid with the antileishmanial drug sodium antimony gluconate (SAG) cures SAG-resistant visceral leishmaniasis.

    PubMed

    Bhattacharjee, Amrita; Majumder, Saikat; Majumdar, Suchandra Bhattacharyya; Choudhuri, Soumitra Kumar; Roy, Syamal; Majumdar, Subrata

    2015-03-01

    Since there are very few affordable antileishmanial drugs available, antimonial resistance has crippled antileishmanial therapy, thereby emphasising the need for development of novel therapeutic strategies. This study aimed to evaluate the antileishmanial role of combined therapy with sodium antimony gluconate (SAG) and the triterpenoid glycyrrhizic acid (GA) against infection with SAG-resistant Leishmania (GE1F8R). Combination therapy with GA and SAG successfully limited infection with SAG-resistant Leishmania in a synergistic manner (fractional inhibitory concentration index <1.0). At the same time, mice infected with SAG-resistant Leishmania and co-treated with GA and SAG exhibited a significant reduction in hepatic and splenic parasite burden. In probing the mechanism, it was observed that GA treatment suppressed the expression and efflux activity of P-glycoprotein (P-gp) and multidrug resistance-associated protein 1 (MRP1), two host ABC transporters responsible for antimony efflux from host cells infected with SAG-resistant parasites. This suppression correlated with greater intracellular antimony retention during SAG therapy both in vitro and in vivo, which was reflected in the reduced parasite load. Furthermore, co-administration of GA and SAG induced a shift in the cytokine balance towards a Th1 phenotype by augmenting pro-inflammatory cytokines (such as IL-12, IFNγ and TNFα) and inducing nitric oxide generation in GE1F8R-infected macrophages as well as GE1F8R-infected mice. This study aims to provide an affordable leishmanicidal alternative to expensive antileishmanial drugs such as miltefosine and amphotericin B. Furthermore, this report explores the role of GA as a resistance modulator in MRP1- and P-gp-overexpressing conditions.

  8. Miltefosine and Antimonial Drug Susceptibility of Leishmania Viannia Species and Populations in Regions of High Transmission in Colombia

    PubMed Central

    Fernández, Olga Lucía; Diaz-Toro, Yira; Muvdi, Sandra; Rodríguez, Isabel; Gomez, María Adelaida; Saravia, Nancy Gore

    2014-01-01

    Background Pentavalent antimonials have been the first line treatment for dermal leishmaniasis in Colombia for over 30 years. Miltefosine is administered as second line treatment since 2005. The susceptibility of circulating populations of Leishmania to these drugs is unknown despite clinical evidence supporting the emergence of resistance. Methodology/Principal Findings In vitro susceptibility was determined for intracellular amastigotes of 245 clinical strains of the most prevalent Leishmania Viannia species in Colombia to miltefosine (HePC) and/or meglumine antimoniate (SbV); 163, (80%) were evaluated for both drugs. Additionally, susceptibility to SbV was examined in two cohorts of 85 L. V. panamensis strains isolated between 1980–1989 and 2000–2009 in the municipality of Tumaco. Susceptibility to each drug differed among strains of the same species and between species. Whereas 68% of L. V. braziliensis strains presented in vitro resistance to HePC, 69% were sensitive to SbV. Resistance to HePC and SbV occurred respectively, in 20% y 21% of L. panamensis strains. Only 3% of L. V. guyanensis were resistant to HePC, and none to SbV. Drug susceptibility differed between geographic regions and time periods. Subpopulations having disparate susceptibility to SbV were discerned among L. V. panamensis strains isolated during 1980–1990 in Tumaco where resistant strains belonged to zymodeme 2.3, and sensitive strains to zymodeme 2.2. Conclusions/Significance Large scale evaluation of clinical strains of Leishmania Viannia species demonstrated species, population, geographic, and epidemiologic differences in susceptibility to meglumine antimoniate and miltefosine, and provided baseline information for monitoring susceptibility to these drugs. Sensitive and resistant clinical strains within each species, and zymodeme as a proxy marker of antimony susceptibility for L. V. panamensis, will be useful in deciphering factors involved in susceptibility and the distribution

  9. Migration of antimony from PET bottles into beverages: determination of the activation energy of diffusion and migration modelling compared with literature data.

    PubMed

    Welle, F; Franz, R

    2011-01-01

    Plastics bottles made from polyethylene terephthalate (PET) are increasingly used for soft drinks, mineral water, juices and beer. In this study a literature review is presented concerning antimony levels found both in PET materials as well as in foods and food simulants. On the other hand, 67 PET samples from the European bottle market were investigated for their residual antimony concentrations. A mean value of 224 ± 32 mg kg(-1) was found, the median was 220 mg kg(-1). Diffusion coefficients for antimony in PET bottle materials were experimentally determined at different temperature between 105 and 150°C. From these data, the activation energy of diffusion for antimony species from the PET bottle wall into beverages and food simulants was calculated. The obtained value of 189 kJ mol(-1) was found to be in good agreement with published data on PET microwave trays (184 kJ mol(-1)). Based on these results, the migration of antimony into beverages was predicted by mathematical migration modelling for different surface/volume ratios and antimony bottle wall concentrations. The results were compared with literature data as well as international legal limits and guidelines values for drinking water and the migration limit set from food packaging legislation. It was concluded that antimony levels in beverages due to migration from PET bottles manufactured according to the state of the art can never reach or exceed the European-specific migration limit of 40 microg kg(-1). Maximum migration levels caused by room-temperature storage even after 3 years will never be essentially higher than 2.5 microg kg(-1) and in any case will be below the European limit of 5 microg kg(-1) for drinking water. The results of this study confirm that the exposure of the consumer by antimony migration from PET bottles into beverages and even into edible oils reaches approximately 1% of the current tolerable daily intake (TDI) established by World Health Organisation (WHO). Having

  10. PANCREATIC TOXICITY AS AN ADVERSE EFFECT INDUCED BY MEGLUMINE ANTIMONIATE THERAPY IN A CLINICAL TRIAL FOR CUTANEOUS LEISHMANIASIS.

    PubMed

    Lyra, Marcelo Rosandiski; Passos, Sonia Regina Lambert; Pimentel, Maria Inês Fernandes; Bedoya-Pacheco, Sandro Javier; Valete-Rosalino, Cláudia Maria; Vasconcellos, Erica Camargo Ferreira; Antonio, Liliane Fatima; Saheki, Mauricio Naoto; Salgueiro, Mariza Mattos; Santos, Ginelza Peres Lima; Ribeiro, Madelon Noato; Conceição-Silva, Fatima; Madeira, Maria Fatima; Silva, Jorge Luiz Nunes; Fagundes, Aline; Schubach, Armando Oliveria

    2016-09-22

    American tegumentary leishmaniasis is an infectious disease caused by a protozoan of the genus Leishmania. Pentavalent antimonials are the first choice drugs for cutaneous leishmaniasis (CL), although doses are controversial. In a clinical trial for CL we investigated the occurrence of pancreatic toxicity with different schedules of treatment with meglumine antimoniate (MA). Seventy-two patients were allocated in two different therapeutic groups: 20 or 5 mg of pentavalent antimony (Sb5+)/kg/day for 20 or 30 days, respectively. Looking for adverse effects, patients were asked about abdominal pain, nausea, vomiting or anorexia in each medical visit. We performed physical examinations and collected blood to evaluate serum amylase and lipase in the pre-treatment period, and every 10 days during treatment and one month post-treatment. Hyperlipasemia occurred in 54.8% and hyperamylasemia in 19.4% patients. Patients treated with MA 20 mg Sb5+ presented a higher risk of hyperlipasemia (p = 0.023). Besides, higher MA doses were associated with a 2.05 higher risk ratio (p = 0.003) of developing more serious (moderate to severe) hyperlipasemia. The attributable fraction was 51% in this group. Thirty-six patients presented abdominal pain, nausea, vomiting or anorexia but only 47.2% of those had hyperlipasemia and/ or hyperamylasemia. These findings suggest the importance of the search for less toxic therapeutic regimens for the treatment of CL.

  11. Separation of Lead from Crude Antimony by Pyro-Refining Process with NaPO3 Addition

    NASA Astrophysics Data System (ADS)

    Ye, Longgang; Hu, Yuejie; Xia, Zhimei; Chen, Yongming

    2016-06-01

    The main purpose of this study was to separate lead from crude antimony through an oxidation pyro-refining process and by using sodium metaphosphate as a lead elimination reagent. The process parameters that will affect the refining results were optimized experimentally under controlled conditions, such as the sodium metaphosphate charging dosage, the refining temperature and duration, and the air flow rate, to determine their effect on the lead content in refined antimony and the lead removal rate. A minimum lead content of 0.0522 wt.% and a 98.6% lead removal rate were obtained under the following optimal conditions: W_{{{NaPO}_{{3}} }} = 15% W Sb (where W represents weight), a refining temperature of 800°C, a refining time of 30 min, and an air flow rate of 3 L/min. X-ray diffractometry and scanning electron microscopy showed that high-purity antimony was obtained. The smelting operation is free from smoke or ammonia pollution when using monobasic sodium phosphate or ammonium dihydrogen phosphate as the lead elimination reagent. However, this refining process can also remove a certain amount of sulfur, cobalt, and silicon simultaneously, and smelting results also suggest that sodium metaphosphate can be used as a potential lead elimination reagent for bismuth and copper refining.

  12. Effect of GeO2 content on structural and spectroscopic properties of antimony glasses doped with Sm3+ ions

    NASA Astrophysics Data System (ADS)

    Zmojda, J.; Kochanowicz, M.; Miluski, P.; Leśniak, M.; Sitarz, M.; Pisarski, W.; Pisarska, J.; Dorosz, D.

    2016-12-01

    Antimony-based glasses with different germanium oxide content doped with Sm3+ ions have been developed. On the basis of decomposition of absorption bands (FTIR) in the mid infrared region, was determined that antimony and germanium ions are the glass-forming ions, setting up the lattice of fabricated glasses. The effect of GeO2/Sb2O3 ratio in fabricated glass doped with samarium ions on thermal, structural and luminescent properties was also investigated. Characteristic bright reddish-orange luminescence from the 4G5/2 state to the lower lying levels 6HJ with J = 5/2, 7/2, 9/2 and 11/2 with maximum intensity at the wavelength of 603 nm originating from 4G5/2 → 6H7/2 transition was observed. The asymmetry nature of molecular structure around samarium ion have been determined from intensity ratio between 4G5/2 → 6H9/2 (ED) and 4G5/2 → 6H5/2 (MD) transitions. An introduction of GeO2 to the antimony glass results in the increasing of 4G5/2 lifetime and decreasing of the orange-to-red intensity ratio, which is are related to reduction of non-briding oxygens.

  13. Remobilization of pentavalent antimony and vanadium from a granular iron hydroxide material--a comparative study of different leaching systems.

    PubMed

    Kolbe, Falko; Weiss, Holger; Wennrich, Rainer; Lorenz, Wilhelm Georg; Daus, Birgit

    2011-09-30

    The remobilization of antimony and vanadium from previously loaded commercial granular ferric-hydroxide GEH material (intended for water treatment) was examined by using a sequential extraction procedure and three different leaching systems to evaluate their physicochemical mobility and potential availability under different simulated environmental conditions. A classical batch extraction, an extraction cell (EC) and rotating-coiled columns (RCC) were used as extraction systems. For each system it could be shown that the content of ion-exchangeable antimony and vanadium in previously loaded material is negligible (<1.5%). The oxyanions were sorbed strongly and could be predominantly remobilized through reducing agents, which means through dissolution of the iron (hydr)oxide matrix. The major advantages of dynamic systems in comparison to batchwise fractionation technique are the drastically reduced extraction time and the possibility of generating information to the leaching kinetics. It is shown that the efficiency of the three leaching systems is quite different employing Wenzel's sequential fractionation protocol. Only by working with RCC, the iron (hydr)oxide matrix was completely dissolved within four steps resulting in the total mobilization of antimony and vanadium. EC seems to be less suitable for leaching studies of Sb and V sorbed on iron(hydr)oxide. The remobilizable proportion of the several fractions was lower in comparison to batch and RCC and seems to be a result of an agglomeration of the GEH in the EC device.

  14. Potentiometric stripping analysis of antimony based on carbon paste electrode modified with hexathia crown ether and rice husk.

    PubMed

    Gadhari, Nayan S; Sanghavi, Bankim J; Srivastava, Ashwini K

    2011-10-03

    An electrochemical method based on potentiometric stripping analysis (PSA) employing a hexathia 18C6 (HT18C6) and rice husk (RH) modified carbon paste electrode (HT18C6-RH-CPE) has been proposed for the subnanomolar determination of antimony. The characterization of the electrode surface has been carried out by means of scanning electron microscopy, cyclic voltammetry, electrochemical impedance spectroscopy and chronocoulometry. By employing HT18C6-RH-CPE, a 12-fold enhancement in the PSA signal (dt/dE) was observed as compared to plain carbon paste electrode (PCPE). Under the optimized conditions, dt/dE (sV(-1)) was proportional to the Sb(III) concentration in the range of 1.42×10(-8) to 6.89×10(-11)M (r=0.9944) with the detection limit (S/N=3) of 2.11×10(-11)M. The practical analytical utilities of the modified electrode were demonstrated by the determination of antimony in pharmaceutical formulations, human hair, sea water, urine and blood serum samples. The prepared modified electrode showed several advantages, such as simple preparation method, high sensitivity, very low detection limit and excellent reproducibility. Moreover, the results obtained for antimony analysis in commercial and real samples using HT18C6-RH-CPE and those obtained by inductively coupled plasma-atomic emission spectrometry (ICP-AES) are in agreement at the 95% confidence level.

  15. Determination of indium in high purity antimony by electrothermal atomic absorption spectrometry (ETAAS) using boric acid as a modifier.

    PubMed

    Dash, K; Thangavel, S; Chaurasia, S C; Arunachalam, J

    2006-10-15

    The use of boric acid as a modifier for the determination of trace amount of indium in high purity antimony by electrothermal atomic absorption is described. It was found that the negative influence of the hydrofluoric acid, used for the digestion could not be eliminated by using stabilized temperature platform furnace (STPF) alone. Due to the high dissociation energy (D(0)=506kJmol(-1)) of indium fluoride, it is difficult to dissociate in the gas phase and hence is lost. In presence of HF (used for the dissolution of antimony), the universal Pd-Mg modifier does not work satisfactorily. Additionally, rising corrosion and reduced tube lifetime were observed when the acid digested (HF-HNO(3)) antimony solution was injected in to the platform. Improvement in platform life and elimination of interferences were achieved by the addition of boric acid as a chemical modifier together with ruthenium coating of the platform. Corrosive changes of the transversely heated graphite atomizer (THGA) platform surface were examined by scanning electron microscopy. The standard addition method was applied. A characteristic mass of 36pg was obtained. The detection limit of the proposed method is around 0.04mugg(-1). The developed method was applied to the determination of indium in real samples. The data obtained by this method were in good agreement with those obtained by ICP-MS.

  16. PANCREATIC TOXICITY AS AN ADVERSE EFFECT INDUCED BY MEGLUMINE ANTIMONIATE THERAPY IN A CLINICAL TRIAL FOR CUTANEOUS LEISHMANIASIS

    PubMed Central

    LYRA, Marcelo Rosandiski; PASSOS, Sonia Regina Lambert; PIMENTEL, Maria Inês Fernandes; BEDOYA-PACHECO, Sandro Javier; VALETE-ROSALINO, Cláudia Maria; VASCONCELLOS, Erica Camargo Ferreira; ANTONIO, Liliane Fatima; SAHEKI, Mauricio Naoto; SALGUEIRO, Mariza Mattos; SANTOS, Ginelza Peres Lima; RIBEIRO, Madelon Noato; CONCEIÇÃO-SILVA, Fatima; MADEIRA, Maria Fatima; SILVA, Jorge Luiz Nunes; FAGUNDES, Aline; SCHUBACH, Armando Oliveria

    2016-01-01

    SUMMARY American tegumentary leishmaniasis is an infectious disease caused by a protozoan of the genus Leishmania. Pentavalent antimonials are the first choice drugs for cutaneous leishmaniasis (CL), although doses are controversial. In a clinical trial for CL we investigated the occurrence of pancreatic toxicity with different schedules of treatment with meglumine antimoniate (MA). Seventy-two patients were allocated in two different therapeutic groups: 20 or 5 mg of pentavalent antimony (Sb5+)/kg/day for 20 or 30 days, respectively. Looking for adverse effects, patients were asked about abdominal pain, nausea, vomiting or anorexia in each medical visit. We performed physical examinations and collected blood to evaluate serum amylase and lipase in the pre-treatment period, and every 10 days during treatment and one month post-treatment. Hyperlipasemia occurred in 54.8% and hyperamylasemia in 19.4% patients. Patients treated with MA 20 mg Sb5+ presented a higher risk of hyperlipasemia (p = 0.023). Besides, higher MA doses were associated with a 2.05 higher risk ratio (p = 0.003) of developing more serious (moderate to severe) hyperlipasemia. The attributable fraction was 51% in this group. Thirty-six patients presented abdominal pain, nausea, vomiting or anorexia but only 47.2% of those had hyperlipasemia and/ or hyperamylasemia. These findings suggest the importance of the search for less toxic therapeutic regimens for the treatment of CL. PMID:27680173

  17. Radio HF precursors of Earthquakes

    NASA Astrophysics Data System (ADS)

    Ruzhin, Yu.; Nomicos, C.; Vallianatos, F.; Shpakovsky, V.

    The high frequency (HF) earthquake electromagnetic precursors (40-55MHz band) were recorded by the four electromagnetic stations a few days (hours) prior the event associated with earthquakes with magnitude more than 5.0 at Crete Island. These experiments were performed continuously during 1998-2002 and specific peculiarities are found. This is underhorizon epicenter position for main part of events under question. Another unusual result is that such HF preseismic radio noise-like signals are responsible for seaquakes too. We made conclusion about developing of some thunderstorm-like charged clouds activity in atmosphere before the seismic event. As result of our analysis and interpretation of the available data of continuous observations on a network of Crete island we should state here, that in an atmosphere above the sea on the eve of earthquake at heights of 0.1-10 km the spatially distributed spots of sporadic charged clouds are occurred and the conditions for the electrical discharges in an atmosphere are created which can serve a source of HF radio-emission registered by Crete network. The atmosphere theory relations are used to model a corresponding to an anomalous event emissions generation observed on the Crete. The supposed mechanism of preseismic electricity generation is the model of convection carrier started in an atmosphere. It is governed by the horizontal gradient of air temperature. The occurrence of electrical charges in a surface of the sea and transportation them further on heights up to 10 km in our model occurs due to sporadic energy injections that allocated within bottom of the sea as gases and heat. The dimensions of width and height govern the size of atmosphere convection cells in the earthquake preparation area. These dimensions of the sporadic spots are close to 3 km each as it is derived from shadow geometry and spectral fluctuations of HF signal. Based on experience of Crete HF precursors observation the method for satellite mapping

  18. Leading time domain seismic precursors

    NASA Astrophysics Data System (ADS)

    Boucouvalas, A. C.; Gkasios, M.; Keskebes, A.; Tselikas, N. T.

    2014-08-01

    The problem of predicting the occurrence of earthquakes is threefold. On one hand it is necessary to predict the date and magnitude of an earthquake, and on the other hand the location of the epicenter. In this work after a brief review of the state of earthquake prediction research, we report on a new leading time precursor for determining time onset of earthquake occurrence. We report the linking between earthquakes of the past with those which happen in the future via Fibonacci, Dual and Lucas numbers (FDL) numbers. We demonstrate it here with two example seed earthquakes at least 100 years old. Using this leading indicator method we can predict significant earthquake events >6.5R, with good accuracy approximately +- 1 day somewhere in the world. From a single seed we produce at least 100 trials simultaneously of which 50% are correct to +- 1day. The indicator is based on Fibonacci, Dual and Lucas numbers (FDL). This result hints that the log periodic FDL numbers are at the root of the understanding of the earthquake mechanism. The theory is based on the assumption that each occurred earthquake discontinuity can be thought of as a generating source of FDL time series. (The mechanism could well be linked to planetary orbits). When future dates are derived from clustering and convergence from previous strong earthquake dates at an FDL time distance, then we have a high probability for an earthquake to occur on that date. We set up a real time system which generates FDL time series from each previous significant earthquake (>7R) and we produce a year to year calendar of high probability earthquake dates. We have tested this over a number of years with considerable success. We have applied this technique for strong (>7R) earthquakes across the globe as well as on a restricted region such as the Greek geographic region where the magnitude is small (>4R-6.5R). In both cases the success of the method is impressive. It is our belief that supplementing this method with

  19. The electronic structure of the antimony chalcogenide series: Prospects for optoelectronic applications

    SciTech Connect

    Carey, John J.; Allen, Jeremy P.; Scanlon, David O.; Watson, Graeme W.

    2014-05-01

    In this study, density functional theory is used to evaluate the electronic structure of the antimony chalcogenide series. Analysis of the electronic density of states and charge density shows that asymmetric density, or ‘lone pairs’, forms on the Sb{sup III} cations in the distorted oxide, sulphide and selenide materials. The asymmetric density progressively weakens down the series, due to the increase in energy of valence p states from O to Te, and is absent for Sb{sub 2}Te{sub 3}. The fundamental and optical band gaps were calculated and Sb{sub 2}O{sub 3}, Sb{sub 2}S{sub 3} and Sb{sub 2}Se{sub 3} have indirect band gaps, while Sb{sub 2}Te{sub 3} was calculated to have a direct band gap at Γ. The band gaps are also seen to reduce from Sb{sub 2}O{sub 3} to Sb{sub 2}Te{sub 3}. The optical band gap for Sb{sub 2}O{sub 3} makes it a candidate as a transparent conducting oxide, while Sb{sub 2}S{sub 3} and Sb{sub 2}Se{sub 3} have suitable band gaps for thin film solar cell absorbers. - Graphical abstract: A schematic illustrating the interaction between the Sb{sup III} cations and the chalcogenide anions and the change in their respective energy levels down the series. - Highlights: • The electronic structure of the antimony chalcogenide series is modelled using DFT. • Asymmetric density is present on distorted systems and absent on the symmetric telluride system. • Asymmetric density is formed from the mixing of Sb 5s and anion p states, where the anti-bonding combination is stabilised by the Sb 5p states. • The asymmetric density weakens down the series due to the increase in energy of chalcogenide p states. • The increase in energy of the anion p states reduces the fundamental and optical band gaps.

  20. Comparative study of hematological responses to platinum group metals, antimony and silver nanoparticles in animal models.

    PubMed

    Newkirk, Catherine E; Gagnon, Zofia E; Pavel Sizemore, Ioana E

    2014-01-01

    Research was conducted to examine the hematological effects of heavy metals (platinum (Pt ((IV))), palladium (Pd ((II))), rhodium (Rh ((III))), antimony (Sb ((III)) and Sb ((V))), and silver nanoparticles (AgNPs)) on white blood cells in mammalian (rat) and avian (chick embryo) models. These metals are used in many everyday products and are accumulating in our environment. Six-week old Sprague-Dawley female rats were treated daily by gavage and six-day old, fertile, specific pathogen-free white leghorn strain chick embryos' eggs were injected on days 7 and 14 of incubation with 0.0, 1.0, 5.0 or 10.0 ppm concentrations of Pt ((IV)) and a platinum group metal (PGM) mix of Pt ((IV)), Pd ((II)) and Rh ((III)). Chick embryos were also tested with 1.0 or 5.0 ppm of antimony compounds (Sb ((III)) and Sb ((V))) and 0.0, 15.0, 30.0, 60.0, or 100.0 ppm of silver nanoparticles (AgNPs). After 8 weeks of treatment, blood was obtained from the rats by jugular cut down and from chick embryos on day 20 of incubation by heart puncture. Blood smears were made and stained and a differential white cell count was performed on each. Examination of the smears revealed unconventional dose responses, stimulation of the immune response, and decreases in leukocyte production with various metals and concentrations. Chick embryos responded differently than rats to Pt and the PGM mix; suggesting that species differences and/or stage of development are important components of response to heavy metals. Route of administration of the metals might also influence the response. All of the heavy metals tested affected the immune responses of the tested animals as demonstrated by changes in the types and numbers of leukocytes. Our findings warrant further research to determine the mechanism of these effects and to understand and prevent toxicological effects in humans and other living organisms.

  1. Comparative toxicity and tissue distribution of antimony potassium tartrate in rats and mice dosed by drinking water or intraperitoneal injection.

    PubMed

    Dieter, M P; Jameson, C W; Elwell, M R; Lodge, J W; Hejtmancik, M; Grumbein, S L; Ryan, M; Peters, A C

    1991-09-01

    Antimony potassium tartrate (APT) is a complex salt that until recently was used worldwide as an antischistosomal drug. Treatment was efficacious only if APT was administered intravenously to humans at a near lethal total dose of 36 mg/kg. Because unconfirmed epidemiologic studies suggested there might be an association between APT treatment and bladder cancer, we initiated prechronic toxicity studies with the drug to select a route of administration and doses in the event that chronic studies of APT were needed. The toxicity and concentration of tissue antimony levels were compared in 14-d studies with F344 rats and B6C3F1 mice administered APT in the drinking water or by ip injection to determine the most appropriate route for longer term studies. Drinking water doses estimated by water consumption were 0, 16, 28, 59, 94 and 168 mg/kg in rats and 0, 59, 98, 174, 273, and 407 mg/kg in mice. APT was poorly absorbed and relatively nontoxic orally, whereas ip administration of the drug caused mortality, body weight decrements, and lesions in the liver and kidney at doses about one order of magnitude below those in drinking water. Because of these data and the dose-related accumulation of antimony in the target organs, an ip dose regimen was selected for subsequent studies. Both sexes of F344 rats and B6C3F1 mice were given 0, 1.5, 3, 6, 12, and 24 mg/kg doses of APT every other day for 90 d by ip injection. There were no clinical signs of toxicity nor gross or microscopic lesions in mice that could be attributed to toxicity of APT, although elevated concentrations of antimony were detected in the liver and spleen of mice. Rats were more sensitive than mice to the toxic effects of APT, exhibiting dose-related mortality, body weight decrements, and hepatotoxicity. The concentrations of antimony measured in liver, blood, kidney, spleen, and heart of rats were proportional to dose, but there were no biochemical changes indicative of toxicity except in the liver

  2. The Interrelationships of Mathematical Precursors in Kindergarten

    ERIC Educational Resources Information Center

    Cirino, Paul T.

    2011-01-01

    This study evaluated the interrelations among cognitive precursors across quantitative, linguistic, and spatial attention domains that have been implicated for math achievement in young children. The dimensionality of the quantity precursors was evaluated in 286 kindergarteners via latent variable techniques, and the contribution of precursors…

  3. Reactions of thiosemicarbazones derived from beta-keto amides and beta-keto esters with Zn(II) and Cd(II) acetates: influence of metal, substitution, reagent ratio and temperature on metal-induced cyclization.

    PubMed

    Casas, José S; Castaño, María V; García-Tasende, María S; Rodríguez-Castellón, Enrique; Sánchez, Agustín; Sanjuán, Luisa M; Sordo, José

    2004-07-07

    Zinc(II) and cadmium(II) acetates were reacted in methanol under various experimental conditions with thiosemicarbazones derived from beta-keto amides or beta-keto esters (HTSC). Some of these reactions afforded thiosemicarbazonate complexes [M(TSC)2] with IR and NMR spectra compatible with N,S-coordination, but most gave complexes [ML2], where HL is a substituted 2,5-dihydro-5-oxo-1H-pyrazole-1-carbothioamide resulting from cyclization of the HTSC. Some of these pyrazolonates and two of the HL ligands were studied by X-ray diffractometry, and their structures are discussed. Surprisingly, the reactions of zinc(II) acetate with HTSC in 1:1 mol ratio usually gave a third, previously unreported type of complex with a dideprotonated ligand, [Zn(L-H)], which was also formed when [ZnL2] and Zn(OAc)2 interacted at room temperature in 1:1 mol ratio. These L-H complexes are highly insoluble in all common solvents, which hinders their characterization but suggests that they are polymeric in nature.

  4. Ligational behavior of thiosemicarbazone, semicarbazone and thiocarbohydrazone ligands towards VO(IV), Ce(III), Th(IV) and UO 2(VI) ions: Synthesis, structural characterization and biological studies

    NASA Astrophysics Data System (ADS)

    Shebl, M.; Seleem, H. S.; El-Shetary, B. A.

    2010-01-01

    Mono- and binuclear VO(IV), Ce(III), Th(IV) and UO 2(VI) complexes of thiosemicarbazone, semicarbazone and thiocarbohydrazone ligands derived from 4,6-diacetylresorcinol were synthesized. The structures of these complexes were elucidated by elemental analyses, IR, UV-vis, ESR, 1H NMR and mass spectra as well as conductivity and magnetic susceptibility measurements and thermal analyses. The thiosemicarbazone (H 4L 1) and the semicarbazone (H 4L 2) ligands behave as dibasic pentadentate ligands in case of VO(IV) and UO 2(VI) complexes, tribasic pentadentate in case of Ce(III) complexes and monobasic pentadentate in case of Th(IV) complexes. However, the thiocarbohydrazone ligand (H 3L 3) acts as a monobasic tridentate ligand in all complexes except the VO(IV) complex in which it acts as a dibasic tridentate ligand. The antibacterial and antifungal activities were also tested against Rhizobium bacteria and Fusarium-Oxysporium fungus. The metal complexes of H 4L 1 ligand showed a higher antibacterial effect than the free ligand while the other ligands (H 4L 2 and H 3L 3) showed a higher effect than their metal complexes. The antifungal effect of all metal complexes is lower than the free ligands.

  5. Vibrational spectroscopy (FT-IR and Laser-Raman) investigation, and computational (M06-2X and B3LYP) analysis on the structure of 4-(3-fluorophenyl)-1-(propan-2-ylidene)-thiosemicarbazone.

    PubMed

    Sert, Yusuf; Miroslaw, Barbara; Çırak, Çağrı; Doğan, Hatice; Szulczyk, Daniel; Struga, Marta

    2014-07-15

    In this study, the experimental and theoretical vibrational spectral analysis of 4-(3-fluorophenyl)-1-(propan-2-ylidene)-thiosemicarbazone have been carried out. The experimental FT-IR (4000-400 cm(-1)) and Laser-Raman spectra (4000-100 cm(-1)) have been recorded for the solid state samples. The theoretical vibrational frequencies and the optimized geometric parameters (bond lengths and angles) have been calculated for gas phase using density functional theory (DFT/B3LYP: Becke, 3-parameter, Lee-Yang-Parr) and M06-2X (the highly parametrized, empirical exchange correlation function) quantum chemical methods with 6-311++G(d,p) basis set. The diversity in molecular geometry of fluorophenyl substituted thiosemicarbazones has been discussed based on the X-ray crystal structure reports and theoretical calculation results from the literature. The assignments of the vibrational frequencies have been done on the basis of potential energy distribution (PED) analysis by using VEDA4 software. A good correlation was found between the computed and experimental geometric and vibrational data. In addition, the highest occupied (HOMO) and lowest unoccupied (LUMO) molecular orbital energy levels and other related molecular energy values of the compound have been determined using the same level of theoretical calculations.

  6. Method of texturing a superconductive oxide precursor

    DOEpatents

    DeMoranville, Kenneth L.; Li, Qi; Antaya, Peter D.; Christopherson, Craig J.; Riley, Jr., Gilbert N.; Seuntjens, Jeffrey M.

    1999-01-01

    A method of forming a textured superconductor wire includes constraining an elongated superconductor precursor between two constraining elongated members placed in contact therewith on opposite sides of the superconductor precursor, and passing the superconductor precursor with the two constraining members through flat rolls to form the textured superconductor wire. The method includes selecting desired cross-sectional shape and size constraining members to control the width of the formed superconductor wire. A textured superconductor wire formed by the method of the invention has regular-shaped, curved sides and is free of flashing. A rolling assembly for single-pass rolling of the elongated precursor superconductor includes two rolls, two constraining members, and a fixture for feeding the precursor superconductor and the constraining members between the rolls. In alternate embodiments of the invention, the rolls can have machined regions which will contact only the elongated constraining members and affect the lateral deformation and movement of those members during the rolling process.

  7. The interrelationships of mathematical precursors in kindergarten.

    PubMed

    Cirino, Paul T

    2011-04-01

    This study evaluated the interrelations among cognitive precursors across quantitative, linguistic, and spatial attention domains that have been implicated for math achievement in young children. The dimensionality of the quantity precursors was evaluated in 286 kindergarteners via latent variable techniques, and the contribution of precursors from each domain was established for small sums addition. Results showed a five-factor structure for the quantity precursors, with the major distinction being between nonsymbolic and symbolic tasks. The overall model demonstrated good fit and strong predictive power (R(2)=55%) for addition number combinations. Linguistic and spatial attention domains showed indirect relationships with outcomes, with their effects mediated by symbolic quantity measures. These results have implications for the measurement of mathematical precursors and yield promise for predicting future math performance.

  8. Exploring the Anti-Cancer Activity of Novel Thiosemicarbazones Generated through the Combination of Retro-Fragments: Dissection of Critical Structure-Activity Relationships

    PubMed Central

    Rasko, Nathalie; Potůčková, Eliška; Mrozek-Wilczkiewicz, Anna; Musiol, Robert; Małecki, Jan G.; Sajewicz, Mieczysław; Ratuszna, Alicja; Muchowicz, Angelika; Gołąb, Jakub; Šimůnek, Tomáš; Richardson, Des R.; Polanski, Jaroslaw

    2014-01-01

    Thiosemicarbazones (TSCs) are an interesting class of ligands that show a diverse range of biological activity, including anti-fungal, anti-viral and anti-cancer effects. Our previous studies have demonstrated the potent in vivo anti-tumor activity of novel TSCs and their ability to overcome resistance to clinically used chemotherapeutics. In the current study, 35 novel TSCs of 6 different classes were designed using a combination of retro-fragments that appear in other TSCs. Additionally, di-substitution at the terminal N4 atom, which was previously identified to be critical for potent anti-cancer activity, was preserved through the incorporation of an N4-based piperazine or morpholine ring. The anti-proliferative activity of the novel TSCs were examined in a variety of cancer and normal cell-types. In particular, compounds 1d and 3c demonstrated the greatest promise as anti-cancer agents with potent and selective anti-proliferative activity. Structure-activity relationship studies revealed that the chelators that utilized “soft” donor atoms, such as nitrogen and sulfur, resulted in potent anti-cancer activity. Indeed, the N,N,S donor atom set was crucial for the formation of redox active iron complexes that were able to mediate the oxidation of ascorbate. This further highlights the important role of reactive oxygen species generation in mediating potent anti-cancer activity. Significantly, this study identified the potent and selective anti-cancer activity of 1d and 3c that warrants further examination. PMID:25329549

  9. Spectrophotometric, voltammetric and cytotoxicity studies of 2-hydroxy-5-methoxyacetophenone thiosemicarbazone and its N(4)-substituted derivatives: A combined experimental-computational study

    NASA Astrophysics Data System (ADS)

    Akgemci, Emine Guler; Saf, Ahmet Ozgur; Tasdemir, Halil Ugur; Türkkan, Ercan; Bingol, Haluk; Turan, Suna Ozbas; Akkiprik, Mustafa

    2015-02-01

    In this study, 2-hydroxy-5-methoxyacetophenone thiosemicarbazone (HMAT) and its novel N(4) substituted derivatives were synthesized and characterized by different techniques. The optical band gap of the compounds and the energy of HOMO were experimentally examined by UV-vis spectra and cyclic voltammetry measurements, respectively. Furthermore, the conformational spaces of the compounds were scanned with molecular mechanics method. The geometry optimization, HOMO and LUMO energies, the energy gap of the HOMO-LUMO, dipole moment of the compounds were theoretically calculated by the density functional theory B3LYP/6-311++G(d,p) level. The minimal electronic excitation energy and maximum wavelength calculations of the compounds were also performed by TD-DFT//B3LYP/6-311++G(d,p) level of theory. Theoretically calculated values were compared with the related experimental values. The combined results exhibit that all compounds have good electron-donor properties which affect anti-proliferative activity. The cytotoxic effects of the compounds were also evaluated against HeLa (cervical carcinoma), MCF-7 (breast carcinoma) and PC-3 (prostatic carcinoma) cell lines using the standard MTT assay. All tested compounds showed antiproliferative effect having IC50 values in different range. In comparison with that of HMAT, it was obtained that while ethyl group on 4(N)-substituted position decreased in potent anti-proliferative effect, the phenyl group on the position increased in anti-proliferative effect for the tested cancer cell line. Considering the molecular energy parameters, the cytotoxicity activities of the compounds were discussed.

  10. Development of highly sensitive extractive spectrophotometric determination of nickel(II) in medicinal leaves, soil, industrial effluents and standard alloy samples using pyridoxal-4-phenyl-3-thiosemicarbazone.

    PubMed

    Sarma, Loka Subramanyam; Kumar, Jyothi Rajesh; Reddy, Koduru Janardhan; Thriveni, Thenepalli; Reddy, Ammireddy Varada

    2008-01-01

    Pyridoxal-4-phenyl-3-thiosemicarbazone (PPT) is proposed as a new sensitive reagent for the extractive spectrophotometric determination of nickel(II). PPT reacts with nickel(II) in the pH range 4.0-6.0 to form a reddish brown colored complex, which was well-extracted into n-butanol. The absorbance value of the Ni(II)-PPT complex was measured at different time intervals at 430nm, to ascertain the stability of the complex. The system obeyed Beer's law up to 0.5-5.0microgmL(-1) of nickel(II), with an excellent linearity in terms of the correlation coefficient value of 0.99. The molar absorptivity and Sandell's sensitivity of the extracted species are 1.92 x 10(4)Lmol(-1)cm(-1) and 0.003057microgcm(-2) respectively at 430nm. The detection limit of the method is 0.069microgmL(-1). To assess precision and accuracy of the developed method, determinations were carried out at different concentrations. The relative standard deviation of all measurements does not exceed 2.62%. The developed method has been satisfactorily applied for the determination of nickel(II), when present alone or in the presence of diverse ions, which are usually associated with nickel(II) in medicinal leaves, soil and industrial effluent samples. Various standard and certified reference materials (CM 247 LC, IN 718, BCS 233, 266, 253 and 251) have also been tested for the determination of nickel for the purpose of validation of the present method. The results of the proposed method are compared with those obtained from an atomic absorption spectrometer (AAS).

  11. Antiviral activity against the hepatitis C virus (HCV) of 1-indanone thiosemicarbazones and their inclusion complexes with hydroxypropyl-β-cyclodextrin.

    PubMed

    Glisoni, Romina J; Cuestas, María L; Mathet, Verónica L; Oubiña, José R; Moglioni, Albertina G; Sosnik, Alejandro

    2012-10-09

    The hepatitis C virus (HCV) is a major cause of acute and chronic hepatitis in humans. Approximately 5% of the infected people die from cirrhosis or hepatocellular carcinoma. The current standard therapy comprises a combination of pegylated-interferon alpha and ribavirin. Due to the relatively low effectiveness, the prohibitive costs and the extensive side effects of the treatment, an intense research for new direct-acting anti-HCV agents is taking place. Furthermore, NS3 protease inhibitors recently introduced into the market are not effective against all HCV subgenotypes. Thiosemicarbazones (TSCs) have shown antiviral activity against a wide range of DNA and RNA viruses. However, their extremely low aqueous solubility and high self-aggregation tendency often preclude their reliable biological evaluation in vitro. In this work, we investigated and compared for the first time the anti-HCV activity of two 1-indanone TSCs, namely 5,6-dimethoxy-1-indanone TSC and 5,6-dimethoxy-1-indanone N4-allyl TSC, and their inclusion complexes with hydroxypropyl-β-cyclodextrin (HPβ-CD) in Huh-7.5 cells containing the full-length and the subgenomic subgenotype 1b HCV replicon system. Studies of physical stability in culture medium showed that free TSCs precipitated rapidly and formed submicron aggregates. Conversely, TSC complexation with HPβ-CD led to more stable systems with minimal size growth and drug concentration loss. More importantly, both TSCs and their inclusion complexes displayed a potent suppression of the HCV replication in both cell lines with no cytotoxic effects. The mechanism likely involves the inhibition of non-structural proteins of the virus. In addition, findings suggested that the cyclodextrin released the drug to the culture medium over time. This platform could be exploited for the study of the drug toxicity and pharmacokinetics animal models.

  12. Evidence for dual mode of action of a thiosemicarbazone, NSC73306: A potent substrate of the multidrug resistance-linked ABCG2 transporter

    PubMed Central

    Wu, Chung-Pu; Shukla, Suneet; Calcagno, Anna Maria; Hall, Matthew D.; Gottesman, Michael M.; Ambudkar, Suresh V.

    2008-01-01

    Multidrug resistance due to reduced drug accumulation is a phenomenon predominantly caused by the overexpression of members of the ATP-binding cassette transporters, including ABCB1 (P-glycoprotein), ABCG2 and several ABCC family members (MRPs). We previously reported that a thiosemicarbazone derivative, NSC73306, is cytotoxic to carcinoma cells that overexpress functional P-glycoprotein and it re-sensitizes these cells to chemotherapeutics. In this study, we investigated the effect of NSC73306 on cells overexpressing other ABC drug transporters, including ABCG2, MRP1, MRP4 and MRP5. Our findings demonstrated that NSC73306 is not more toxic to cells that overexpress these transporters compared to their respective parental cells, and these transporters do not confer resistance to NSC73306 either. In spite of this, we observed that NSC73306 is a transport substrate for ABCG2 that can effectively inhibit ABCG2-mediated drug transport and reverse resistance to both mitoxantrone and topotecan in ABCG2-expressing cells. Interactions between NSC73306 and the ABCG2 drug-binding site(s) were confirmed by its stimulatory effect on ATPase activity (140–150 nM concentration required for 50% stimulation) and by inhibition of [125I]-Iodoarylazidoprazosin photolabeling (50% inhibition at 250–400 nM) of the substrate-binding site(s). Overall, NSC73306 appears to be a potent modulator of ABCG2 that does not interact with MRP1, MRP4 or MRP5. Collectively, these data suggest that NSC73306 can potentially be used, due to its dual mode of action, as an effective agent to overcome drug resistance by eliminating P-glycoprotein-overexpressing cells, and by acting as a potent modulator that re-sensitizes ABCG2-expressing cancer cells to chemotherapeutics. PMID:18089722

  13. Uptake of compounds that selectively kill multidrug-resistant cells: the copper transporter SLC31A1 (CTR1) increases cellular accumulation of the thiosemicarbazone NSC73306.

    PubMed

    Fung, King Leung; Tepede, Abisola K; Pluchino, Kristen M; Pouliot, Lynn M; Pixley, Jessica N; Hall, Matthew D; Gottesman, Michael M

    2014-08-04

    Acquired drug resistance in cancer continues to be a challenge in cancer therapy, in part due to overexpression of the drug efflux transporter P-glycoprotein (P-gp, MDR1, ABCB1). NSC73306 is a thiosemicarbazone compound that displays greater toxicity against cells expressing functional P-gp than against other cells. Here, we investigate the cellular uptake of NSC73306, and examine its interaction with P-gp and copper transporter 1 (CTR1, SLC31A1). Overexpression of P-gp sensitizes LLC-PK1 cells to NSC73306. Cisplatin (IC50 = 77 μM), cyclosporin A (IC50 = 500 μM), and verapamil (IC50 = 700 μM) inhibited cellular accumulation of [(3)H]NSC73306. Cellular hypertoxicity of NSC73306 to P-gp-expressing cells was inhibited by cisplatin in a dose-dependent manner. Cells transiently expressing the cisplatin uptake transporter CTR1 (SLC31A1) showed increased [(3)H]NSC73306 accumulation. In contrast, CTR1 knockdown decreased [(3)H]NSC73306 accumulation. The presence of NSC73306 reduced CTR1 levels, similar to the negative feedback of CTR1 levels by copper or cisplatin. Surprisingly, although cisplatin is a substrate of CTR1, we found that CTR1 protein was overexpressed in high-level cisplatin-resistant KB-CP20 and BEL7404-CP20 cell lines. We confirmed that the CTR1 protein was functional, as uptake of NSC73306 was increased in KB-CP20 cells compared to their drug-sensitive parental cells, and downregulation of CTR1 in KB-CP20 cells reduced [(3)H]NSC73306 accumulation. These results suggest that NSC73306 is a transport substrate of CTR1.

  14. Design, synthesis and biological evaluation of novel 4-phenoxy-6,7-disubstituted quinolines possessing (thio)semicarbazones as c-Met kinase inhibitors.

    PubMed

    Zhai, Xin; Bao, Guanglong; Wang, Limei; Cheng, Mingke; Zhao, Meng; Zhao, Sijia; Zhou, Hongyang; Gong, Ping

    2016-03-15

    In continuing our efforts to identify small molecules able to inhibit c-Met kinase, three series of novel 6,7-disubstituted-4-phenoxyquinoline derivatives (23a-w, 26a-d and 30a-d) bearing (thio)semicarbazone scaffold were designed, synthesized and evaluated for their cytotoxicity. The biological data revealed that most compounds exhibited moderate-to-excellent activity against HT-29, MKN-45, A549 cancer cell lines and relative poor potency toward MDA-MB-231 cell as well as hardly any cytotoxicity in normal PBL cell. Eleven compounds were further examined for their inhibitory activity against c-Met kinase and three compounds (23h, 23n and 26a) demonstrated good inhibitory activity. This work resulted in the discovery of a potent c-Met inhibitor 23n, bearing 2-hydroxy-3-allylphenyl group at R(2) moiety, as a valuable lead molecule, which possessed remarkable cytotoxicity and high selectivity against A549 and HT-29 cell lines with IC50 values of 11 nM and 27 nM. Besides, it displayed excellent c-Met kinase inhibition on a single-digital nanomolar level (IC50=1.54 nM). Meanwhile, the results from preliminarily in vivo study reflected that compound 23n showed promising overall PK profiles, consistent with the efficacy in both MKN-45 and HT-29 tumor xenograft mice model. These results clearly indicated that compound 23n is a potent and highly selective c-Met inhibitor and its favorable in vitro and in vivo profiles warrant further investigation.

  15. Local bonding structure of tellurium and antimony in the phase change chalcogenides germanium-antimony-tellurium: A nuclear magnetic resonance study

    NASA Astrophysics Data System (ADS)

    Bobela, David C.

    Recent technological applications of some chalcogenide materials, compounds containing a group VI atom, have prompted studies of the local atomic structure of the amorphous phase. In the case of Ge2Sb2Te 5, metastability in the local bonding structure is responsible for its usefulness as a phase-change memory material. There is no consensus on the exact phase-change mechanism, which is partly due to the inadequacy of standard scattering techniques to probe the structure of the amorphous phase. Nuclear magnetic resonance methods, on the other hand, are well suited to study local structural order even in the absence of a periodic lattice. In this technique, structural information is encoded as an oscillating voltage caused by the nuclear spin. For the tellurium isotope, 125Te (spin = 1/2 in the ground state), the dominant interaction comes from the core and valence electrons that carry angular momentum. This interaction is helpful in identifying Te sites of different local coordination since the number of neighboring atoms should markedly change the local electronic structure. The antimony isotope 125Sb has a spin = 5/2 in the ground state and possesses an asymmetric nuclear charge. This quadrupole moment will interact with an electric field gradient at the nuclear site, which is provided by an asymmetric electron cloud surrounding the nucleus. The frequency-space spectra will reflect the strength of the interaction as well as the symmetry of the local electronic environment. This work investigates the nuclear magnetic resonance spectrum of 125Te and 125Sb in the crystalline and amorphous forms of several GexSbyTe 1-x-y compounds where 0 < (x, y) < 1. Results from the crystalline phase 125Te data show a trend in the spectral position that can be related to the tellurium bonded to three and six neighbors. In the amorphous phase, the same trend is observed, and the nuclear magnetic resonance fingerprint of two-fold and three-fold coordinated tellurium is obtained. It

  16. Antimony release from contaminated mine soils and its migration in four typical soils using lysimeter experiments.

    PubMed

    Shangguan, Yu-Xian; Zhao, Long; Qin, Yusheng; Hou, Hong; Zhang, Naiming

    2016-11-01

    Antimony (Sb) can pose great risks to the environment in mining and smelting areas. The migration of Sb in contaminated mine soil was studied using lysimeter experiments. The exchangeable concentration of soil Sb decreased with artificial leaching. The concentrations of Sb retained in the subsoil layers (5-25cm deep) were the highest for Isohumosol and Ferrosol and the lowest for Sandy soil. The Sb concentrations in soil solutions decreased with soil depth, and were adequately simulated using a logarithmic function. The Sb migration pattern in Sandy soil was markedly different from the patterns in the other soils which suggested that Sb may be transported in soil colloids. Environmental factors such as water content, soil temperature, and oxidation-reduction potential of the soil had different effects on Sb migration in Sandy soil and Primosol. The high Fe and Mn contents in Ferrosol and Isohumosol significantly decreased the mobility of Sb in these soils. The Na and Sb concentrations in soils used in the experiments positively correlated with each other (P<0.01). The Sb concentrations in soil solutions, the Sb chemical fraction patterns, and the Sb/Na ratios decreased in the order Sandy soil>Primosol>Isohumosol>Ferrosol, and we concluded that the Sb mobility in the soils also decreased in that order.

  17. Atomic oxygen interaction with nickel multilayer and antimony oxide doped MoS{sub 2} films

    SciTech Connect

    Dugger, M.T.

    1994-12-31

    Sputtered MoS{sub 2} is a solid lubricant capable of ultralow friction coefficients (below 0.05) load-bearing capacity. Since it exhibits low friction in vacuum, low outgassing rate, is non-migrating and lacks organic binders, this material is an attractive lubricant for space mechanisms. To exploit these new materials to their fullest potential, designers of space-based motion systems require data on the effects of atomic oxygen exposure on dense, sputtered MoS{sub 2}. This paper describes the effects of atomic oxygen in low earth orbit on the friction and surface composition of sputtered MoS{sub 2} films. Sputtered multilayer films of MoS{sub 2} with nickel (0.7 nm Ni per 10 nm MoS{sub 2}, for 1 {mu}m total film thickness), and MoS{sub 2} cosputtered with antimony oxide (nominally 2 {mu}m thick) were exposed to 2.2 to 2.5 x 10{sup 20} oxygen/cm{sup 2} over a period of 42.25 hours in earth orbit on the United States space shuttle. Identical specimens were kept as controls in desiccated storage for the duration of the mission, and another set was exposed to an equivalent fluence of atomic oxygen in the laboratory. The friction coefficient in air and vacuum, and the composition of worn surfaces, were determined prior to the shuttle flight and again after the shuttle flight. Results are described.

  18. Facile Control of Interfacial Energy-Barrier Scattering in Antimony Telluride Electrodeposits

    NASA Astrophysics Data System (ADS)

    Kim, Jiwon; Jung, Hyunsung; Lim, Jae-Hong; Myung, Nosang V.

    2017-04-01

    The augmented thermoelectric performance of nanocrystalline antimony telluride (Sb2Te3) films is investigated by introducing interfacial energy-barrier scattering (i.e., barrier heights), which occurs at both the grain boundaries and the interfaces with embedded second phases. It is postulated that the barriers created at both the interfaces and boundaries filter the low-energy carriers, thus favoring a high Seebeck coefficient. A facile, but high-precision composition-controlled electrodeposition technique is employed to synthesize single-phase nanocrystalline Sb2Te3 and nanocomposite Te/Sb2Te3. Both the initial composition of the Sb-Te solid solution and the post-annealing profiles are varied to control the grain size, as well as the formation of second-phase Te. The electrical and thermoelectric properties are measured and correlated with the physical properties, where an enhanced Seebeck coefficient at a fixed carrier concentration is interpreted as indicating that the energy-dependent carrier filtering effect is in force. On a promising note, modification of the Sb2Te3 film physical properties and formation of the second phase affect the interfacial energy-barrier scattering and yields an enhanced power factor. Thus, Sb2Te3 film is a promising p-type thermoelectric material for a room-temperature-operational micro-thermoelectric power generator.

  19. Mitigation of Sulfur Poisoning of Ni/Zirconia SOFC Anodes by Antimony and Tin

    SciTech Connect

    Marina, Olga A.; Coyle, Christopher A.; Engelhard, Mark H.; Pederson, Larry R.

    2011-02-28

    Surface Ni/Sb and Ni/Sb alloys were found to efficiently minimize the negative effects of sulfur on the performance of Ni/zirconia anode-supported solid oxide fuel cells (SOFC). Prior to operating on fuel gas containing low concentrations of H2S, the nickel/zirconia anodes were briefly exposed to antimony or tin vapor, which only slightly affected the SOFC performance. During the subsequent exposures to 1 and 5 ppm H2S, increases in anodic polarization losses were minimal compared to those observed for the standard nickel/zirconia anodes. Post-test XPS analyses showed that Sb and Sn tended to segregate to the surface of Ni particles, and further confirmed a significant reduction of adsorbed sulfur on the Ni surface in Ni/Sn and Ni/Sb samples compared to the Ni. The effect may be the result of weaker sulfur adsorption on bimetallic surfaces, adsorption site competition between sulfur and Sb or Sn on Ni, or other factors. The use of dilute binary alloys of Ni-Sb or Ni-Sn in the place of Ni, or brief exposure to Sb or Sn vapor, may be effective means to counteract the effects of sulfur poisoning in SOFC anodes and Ni catalysts. Other advantages, including suppression of coking or tailoring the anode composition for the internal reforming, are also expected.

  20. Spatial distribution and transport characteristics of heavy metals around an antimony mine area in central China.

    PubMed

    Li, Xin; Yang, Hong; Zhang, Chang; Zeng, Guangming; Liu, Yunguo; Xu, Weihua; Wu, Youe; Lan, Shiming

    2017-03-01

    The spatial distribution and transport characteristics of heavy metals in an antimony mine area (Xikuangshan, China) were systematically studied using a field survey and geostatistical analytical methods. In the study area, 52 soil and sediment samples were collected from bare land, grassland, woodland and river sediments covering a surface area of 20 km(2). The soil properties and heavy metal concentrations were measured by wavelength dispersive X-ray fluorescence spectrometry and inductively coupled plasma-mass spectrometry, respectively. Correlation analysis and principal component analysis suggest that Cu, Zn, Cd, As, Pb and Sb can be attributed to anthropogenic inputs, whereas Cr, Mn and Ni are of natural origin. Distribution maps of heavy metals were generated using the Kriging interpolation method to identify their distribution trends. The results show the influence of wind, river, distance and vegetation on the spatial distribution. The results also revealed that windborne transport may play a significant role in the spreading of contaminants. In addition, the environmental risk of heavy metal pollution was evaluated using their geoaccumulation indexes in the whole region. All of the results indicate that the heavy metal distributions in the soils were consistent with the local prevailing wind direction. In addition, the environmental quality could be seriously threatened by heavy metal contaminants from the smelter and tailings.

  1. Antimony-Doped Tin Oxide Thin Films Grown by Home Made Spray Pyrolysis Technique

    NASA Astrophysics Data System (ADS)

    Yusuf, Gbadebo; Babatola, Babatunde Keji; Ishola, Abdulahi Dimeji; Awodugba, Ayodeji O.; Solar cell Collaboration

    2016-03-01

    Transparent conducting antimony-doped tin oxide (ATO) films have been deposited on glass substrates by home made spray pyrolysis technique. The structural, electrical and optical properties of the ATO films have been investigated as a function of Sb-doping level and annealing temperature. The optimum target composition for high conductivity and low resistivity was found to be 20 wt. % SnSb2 + 90 wt. ATO. Under optimized deposition conditions of 450oC annealing temperature, electrical resistivity of 5.2×10-4 Ω -cm, sheet resistance of 16.4 Ω/sq, average optical transmittance of 86% in the visible range, and average optical band-gap of 3.34eV were obtained. The film deposited at lower annealing temperature shows a relatively rough, loosely bound slightly porous surface morphology while the film deposited at higher annealing temperature shows uniformly distributed grains of greater size. Keywords: Annealing, Doping, Homemade spray pyrolysis, Tin oxide, Resistivity

  2. Risk assessment from exposure to arsenic, antimony, and selenium in urban gardens (Madrid, Spain).

    PubMed

    De Miguel, Eduardo; Izquierdo, Miguel; Gómez, Amaia; Mingot, Juan; Barrio-Parra, Fernando

    2017-02-01

    The authors discuss the geochemical behavior of arsenic (As), antimony (Sb), and selenium (Se) in urban gardens and the human health implications associated with urban agriculture. A total of 42 samples from 7 urban gardens in Madrid, Spain, were collected from the top 20 cm of soil. Concentrations of As, Sb, and Se and the main soil properties (i.e., total iron, pH, texture, calcium carbonate, and organic matter) were determined. A significant correlation was found between As and Sb and calcium carbonate, indicating the possibility of surface adsorption or ligand exchange with the carbonate group. Also, Sb seemed to form stable chelates with soil organic matter. On the other hand, Se showed a significant association with clay and iron content. The concentration of Sb in soil exceeded the recommended value for agricultural use in 70% of the urban gardens. A human health risk assessment resulted in acceptable levels of both noncarcinogenic and carcinogenic risks (although with elevated values of the latter), with As as the main risk driver and soil and food ingestion as the main exposure pathways. The numerical results of the risk assessment should be interpreted with caution given the considerable uncertainties in some exposure variables and the lack of quantitative values for the suspected carcinogenicity of Sb and Se. Environ Toxicol Chem 2017;36:544-550. © 2016 SETAC.

  3. Assessment and distribution of antimony in soils around three coal mines, Anhui, China

    USGS Publications Warehouse

    Qi, C.; Liu, Gaisheng; Kang, Y.; Lam, P.K.S.; Chou, C.

    2011-01-01

    Thirty-three soil samples were collected from the Luling, Liuer, and Zhangji coal mines in the Huaibei and Huainan areas of Anhui Province, China. The samples were analyzed for antimony (Sb) by inductively coupled plasmaoptical emission spectrometry (ICP-OES) method. The average Sb content in the 33 samples was 4 mg kg-1, which is lower than in coals from this region (6.2 mg kg-1). More than 75% of the soils sampled showed a significant degree of Sb pollution (enrichment factors [EFs] 5-20). The soils collected near the gob pile and coal preparation plant were higher in Sb content than those collected from residential areas near the mines. The gob pile and tailings from the preparation plant were high in mineral matter content and high in Sb. They are the sources of Sb pollution in surface soils in the vicinity of coal mines. The spatial dispersion of Sb in surface soil in the mine region shows that Sb pollution could reach out as far as 350 m into the local environment conditions. Crops in rice paddies may adsorb some Sb and reduce the Sb content in soils from paddyfields. Vertical distribution of Sb in two soil profiles indicates that Sb is normally relatively immobile in soils. ?? 2011 Air & Waste Management Association.

  4. Silver antimony Ohmic contacts to moderately doped n-type germanium

    SciTech Connect

    Dumas, D. C. S.; Gallacher, K.; Millar, R.; Paul, D. J.; MacLaren, I.; Myronov, M.; Leadley, D. R.

    2014-04-21

    A self doping contact consisting of a silver/antimony alloy that produces an Ohmic contact to moderately doped n-type germanium (doped to a factor of four above the metal-insulator transition) has been investigated. An evaporation of a mixed alloy of Ag/Sb (99%/1%) onto n-Ge (N{sub D}=1×10{sup 18} cm{sup −3}) annealed at 400 °C produces an Ohmic contact with a measured specific contact resistivity of (1.1±0.2)×10{sup −5} Ω-cm{sup 2}. It is proposed that the Ohmic behaviour arises from an increased doping concentration at the Ge surface due to the preferential evaporation of Sb confirmed by transmission electron microscope analysis. It is suggested that the doping concentration has increased to a level where field emission will be the dominate conduction mechanism. This was deduced from the low temperature electrical characterisation of the contact, which exhibits Ohmic behaviour down to a temperature of 6.5 K.

  5. [Interlaboratory study on migration test of antimony and germanium for food-contact polyethylene terephthalate].

    PubMed

    Murakami, Ryo; Mutsuga, Motoh; Abe, Takashi; Abe, Yutaka; Ohsaka, Ikue; Ohno, Haruka; Ohno, Hiroyuki; Ohno, Yuichiro; Ozaki, Asako; Kakihara, Yoshiteru; Kawasaki, Hiromi; Kobayashi, Hisashi; Shibata, Hiroshi; Shirono, Katsuhiro; Sekido, Haruko; Sonobe, Hironori; Takasaka, Noriko; Tajima, Yoshiyasu; Tanaka, Aoi; Tanaka, Hideyuki; Nomura, Chie; Haneishi, Nahoko; Hikida, Akinori; Miura, Toshihiko; Watanabe, Kazunari; Akiyama, Hiroshi

    2015-01-01

    An interlaboratory study was performed to evaluate a migration test method of antimony (Sb) and germanium (Ge), based on the Japanese Food Sanitation Law for food- contact polyethylene terephthalate. Eighteen laboratories participated, and quantified Sb and Ge in three test solutions as blind duplicates using graphite furnace atomic absorption spectrometry (GF-AAS), inductively coupled plasma-optical emission spectrometry (ICP-OES) or induced coupled plasma-mass spectrometry (ICP-MS). Statistical analysis revealed that the trueness, repeatability and reproducibility were 98-107%, 1.7-7.5% and 2.0-18.8% by using GF-AAS and ICP-OES. The performance of these methods is sufficient for testing the specifications. The performance parameters of ICP-MS were 99-106%, 0.7-2.2% and 2.2-10.5%, respectively. ICP-MS is available as an alternative measuring method. However, in some laboratories, the quantitative values of Sb were higher than the addition levels. We found that Sb in working solutions is absorbed on glass vessels. Careful control of concentration in working solutions is required for Sb analysis.

  6. Rashba effect in single-layer antimony telluroiodide SbTeI

    DOE PAGES

    Zhuang, Houlong L.; Cooper, Valentino R.; Xu, Haixuan; ...

    2015-09-04

    Exploring spin-orbit coupling (SOC) in single-layer materials is important for potential spintronics applications. In this paper, using first-principles calculations, we show that single-layer antimony telluroiodide SbTeI behaves as a two-dimensional semiconductor exhibiting a G0W0 band gap of 1.82 eV. More importantly, we observe the Rashba spin splitting in the SOC band structure of single-layer SbTeI with a sizable Rashba coupling parameter of 1.39 eV Å, which is significantly larger than that of a number of two-dimensional systems including surfaces and interfaces. The low formation energy and real phonon modes of single-layer SbTeI imply that it is stable. Finally, our studymore » suggests that single-layer SbTeI is a candidate single-layer material for applications in spintronics devices.« less

  7. A Multiplatform Metabolomic Approach to the Basis of Antimonial Action and Resistance in Leishmania infantum

    PubMed Central

    Castilho-Martins, Emerson A.; Tavares, Marina F. M.; Barbas, Coral; López-Gonzálvez, Ángeles; Rivas, Luis

    2015-01-01

    There is a rising resistance against antimony drugs, the gold-standard for treatment until some years ago. That is a serious problem due to the paucity of drugs in current clinical use. In a research to reveal how these drugs affect the parasite during treatment and to unravel the underlying basis for their resistance, we have employed metabolomics to study treatment in Leishmania infantum promastigotes. This was accomplished first through the untargeted analysis of metabolic snapshots of treated and untreated parasites both resistant and responders, utilizing a multiplatform approach to give the widest as possible coverage of the metabolome, and additionally through novel monitoring of the origin of the detected alterations through a 13C traceability experiment. Our data stress a multi-target metabolic alteration with treatment, affecting in particular the cell redox system that is essential to cope with detoxification and biosynthetic processes. Additionally, relevant changes were noted in amino acid metabolism. Our results are in agreement with other authors studying other Leishmania species. PMID:26161866

  8. Cryogenic Thermoelectric Properties of the Bismuth-Magnesium and Bismuth-Antimony-Magnesium Systems

    NASA Astrophysics Data System (ADS)

    Orovets, Christine; Jin, Hyungyu; Wiendlocha, Bartlomiej; Heremans, Joseph P.

    2012-02-01

    There is a need to increase the Figure of Merit of thermoelectric materials used in low temperature cooling applications. Band structure calculations show that substitutional magnesium in bismuth can form sharp density of states peaks, suggesting the presence of a resonant level. Single crystal samples of (Bi1-xSbx)1-yMgy (0 <= x <= 12% and 0 <= y <= 0.7% nominally) were synthesized in evacuated ampoules. The composition of each ingot was analyzed using x-ray diffraction, and transport properties were measured using a Thermal Transport Option (TTO) in a Physical Properties Measurement System (PPMS) from 300K to 2K. It is apparent that the addition of magnesium strongly influences thermopower; the data for Bi90Sb10Mg0.7 shows a second minimum in thermopower at 20K, in addition to the expected minimum at approximately 50-60K. This could be due to the resonant scattering at the cryogenic temperatures which arises from the excess density of states. The addition of magnesium also appears to decrease thermal conductivity below 30K. We present systematic experimental approaches and the results to elucidate the role of magnesium in bismuth and bismuth-antimony systems.

  9. Semimetal Nanomaterials of Antimony as Highly Efficient Agent for Photoacoustic Imaging and Photothermal Therapy

    PubMed Central

    Li, Wanwan; Rong, Pengfei; Yang, Kai; Huang, Peng; Sun, Kang; Chen, Xiaoyuan

    2017-01-01

    In this study we report semimetal naonmaterials of antimony (Sb) as highly efficient agent for photoacoustic imaging (PAI) and photothermal therapy (PTT). The Sb nanorod bundles have been synthesized through a facile route by mixing 1-octadecane (ODE) and oleyl amine (OAm) as the solvent. The aqueous dispersion of PEGylated Sb NPs, due to its broad and strong photoabsorption ranging from ultraviolet (UV) to near-infrared (NIR) wavelengths, is applicable as a photothermal agent driven by 808 nm laser with photothermal conversion efficiency up to 41%, noticeably higher than most of the PTT agents reported before. Our in vitro experiments also showed that cancer cell ablation effect of PEGylated Sb NPs was dependent on laser power. By intratumoral administration of PEGylated Sb NPs, 100% tumor ablation can be realized by using NIR laser irradiation with a lower power of 1 W/cm2 for 5 min (or 0.5 W/cm2 for 10 min) and no obvious toxic side effect is identified after photothermal treatment. Moreover, intense PA signal was also observed after intratumoral injection of PEGylated Sb NPs and NIR laser irradiation due to their strong NIR photoabsorption, suggesting PEGylated Sb NPs as a potential NIR PA agent. Based on the findings of this work, futher development of using other smimetal nanocrystals as highly efficient NIR agents can be achieved for vivo tumor imaging and PTT. PMID:25662491

  10. Antimony nanoparticles anchored in three-dimensional carbon network as promising sodium-ion battery anode

    NASA Astrophysics Data System (ADS)

    Luo, Wen; Zhang, Pengfei; Wang, Xuanpeng; Li, Qidong; Dong, Yifan; Hua, Jingchen; Zhou, Liang; Mai, Liqiang

    2016-02-01

    A novel composite with antimony (Sb) nanoparticles anchored in three-dimensional carbon network (denoted as SbNPs@3D-C) is successfully synthesized via a NaCl template-assisted self-assembly strategy, followed by freeze-drying and one-step in-situ carbonization. The three-dimensional interconnected macroporous carbon framework can not only stabilize the architecture and buffer the volume expansion for Sb nanoparticles, but also provide high electrical conductivity for the whole electrode. Consequently, as a sodium-ion battery anode, the SbNPs@3D-C delivers a high reversible capacity (456 mAh g-1 at 100 mA g-1), stable cycling performance (94.3% capacity retention after 500 cycles at 100 mA g-1) as well as superior rate capability (270 mAh g-1 at 2000 mA g-1). When compared with commercial Sb particles, the SbNPs@3D-C exhibits dramatically enhanced electrochemical performance. Free from expensive template sources and complex manipulation, this work might shed some light on the synthesis of low-cost and high-performance materials for the next "beyond lithium" battery generation.

  11. Synthesis of Copper-Antimony-Sulfide Nanocrystals for Solution-Processed Solar Cells.

    PubMed

    Suehiro, Satoshi; Horita, Keisuke; Yuasa, Masayoshi; Tanaka, Tooru; Fujita, Katsuhiko; Ishiwata, Yoichi; Shimanoe, Kengo; Kida, Tetsuya

    2015-08-17

    The p-type nanocrystals (NCs) of copper-based chalcogenides, such as CuInSe2 and Cu2ZnSnS4, have attracted increasing attention in photovoltaic applications due to their potential to produce cheap solution-processed solar cells. Herein, we report the synthesis of copper-antimony-sulfide (CAS) NCs with different crystal phases including CuSbS2, Cu3SbS4, and Cu12Sb4S13. In addition, their morphology, crystal phase, and optical properties were characterized using transmission electron microscopy, X-ray diffractometry, UV-vis-near-IR spectroscopy, and photoemission yield spectroscopy. The morphology, crystal phase, and electronic structure were significantly dependent on the chemical composition in the CAS system. Devices were fabricated using particulate films consisting of CAS NCs prepared by spin coating without a high-temperature treatment. The CAS NC-based devices exhibited a diode-like current-voltage characteristic when coupled with an n-type CdS layer. In particular, the CuSbS2 NC devices exhibited photovoltaic responses under simulated sunlight, demonstrating its applicability for use in solution-processed solar cells.

  12. Usage of antimony segregation for selective doping of Si in molecular beam epitaxy

    SciTech Connect

    Yurasov, D. V.; Drozdov, M. N.; Murel, A. V.; Shaleev, M. V.; Novikov, A. V.; Zakharov, N. D.

    2011-06-01

    An original approach to selective doping of Si by antimony (Sb) in molecular beam epitaxy (MBE) is proposed and verified experimentally. This approach is based on controllable utilization of the effect of Sb segregation. In particular, the sharp dependence of Sb segregation on growth temperature in the range of 300-550 deg. C is exploited. The growth temperature variations between the kinetically limited and maximum segregation regimes are suggested to be utilized in order to obtain selectively doped structures with abrupt doping profiles. It is demonstrated that the proposed technique allows formation of selectively doped Si:Sb layers, including delta ({delta}-)doped layers in which Sb concentrations can be varied from 5 x 10{sup 15} to 10{sup 20} cm{sup -3}. The obtained doped structures are shown to have a high crystalline quality and the short-term growth interruptions, which are needed to change the substrate temperature, do not lead to any significant accumulation of background impurities in grown samples. Realization of the proposed approach requires neither too low (<300 deg. C), nor too high (>600 deg. C) growth temperatures or any special equipment for the MBE machines.

  13. Direct Band Gap Gallium Antimony Phosphide (GaSbxP1−x) Alloys

    PubMed Central

    Russell, H. B.; Andriotis, A. N.; Menon, M.; Jasinski, J. B.; Martinez-Garcia, A.; Sunkara, M. K.

    2016-01-01

    Here, we report direct band gap transition for Gallium Phosphide (GaP) when alloyed with just 1–2 at% antimony (Sb) utilizing both density functional theory based computations and experiments. First principles density functional theory calculations of GaSbxP1−x alloys in a 216 atom supercell configuration indicate that an indirect to direct band gap transition occurs at x = 0.0092 or higher Sb incorporation into GaSbxP1−x. Furthermore, these calculations indicate band edge straddling of the hydrogen evolution and oxygen evolution reactions for compositions ranging from x = 0.0092 Sb up to at least x = 0.065 Sb making it a candidate for use in a Schottky type photoelectrochemical water splitting device. GaSbxP1−x nanowires were synthesized by reactive transport utilizing a microwave plasma discharge with average compositions ranging from x = 0.06 to x = 0.12 Sb and direct band gaps between 2.21 eV and 1.33 eV. Photoelectrochemical experiments show that the material is photoactive with p-type conductivity. This study brings attention to a relatively uninvestigated, tunable band gap semiconductor system with tremendous potential in many fields. PMID:26860470

  14. Effects of antimony trisulfide (Sb2S3) on sliding friction of automotive brake friction materials

    NASA Astrophysics Data System (ADS)

    Lee, Wan Kyu; Rhee, Tae Hee; Kim, Hyun Seong; Jang, Ho

    2013-09-01

    The effect of antimony trisulfide (Sb2S3) on the tribological properties of automotive brake friction materials was investigated using a Krauss type tribometer and a 1/5 scale dynamometer with a rigid caliper. Results showed that Sb2S3 improved fade resistance by developing transfer films on the disc surface at elevated temperatures. On the other hand, the rubbing surfaces of the friction material exhibited contact plateaus with a broader height distribution when it contained Sb2S3, indicating fewer contact junctions compared to the friction material with graphite. The friction material with Sb2S3 also exhibited a lower stick-slip propensity than the friction material with graphite. The improved fade resistance with Sb2S3 is attributed to its lubricating capability sustained at high temperatures, while the lower stick-slip propensity of the friction material with Sb2S3 is associated with the slight difference between its static and kinetic coefficients of friction and high normal stiffness.

  15. Linear and nonlinear optical response of bismuth and antimony implanted fused silica: annealing effects

    NASA Astrophysics Data System (ADS)

    Pan, Z.; Morgan, S. H.; Henderson, D. O.; Park, S. Y.; Weeks, R. A.; Magruder, R. H.; Zuhr, R. A.

    1995-10-01

    We report the linear and nonlinear optical response of bismuth and antimony implanted fused silica with doses of 6 × 10 16 ions/cm 2. The nonlinear refractive index, n2, was measured using a Z-scan technique with a mode locked Ti:sapphire laser operating in 140 fs pulse duration at 770 nm wavelength. It is found that the nonlinear refractive index n2 of as-implanted samples is large, in the order of 10 -10 cm 2/W and the n2 value of Bi as-implanted sample is about 2.4 times lager than that of Sb as-implanted sample. The large n2 response is attributed to the presence of nanosized metal particles in the implanted layer observed by transmission electron microscopy. We also report the changes of linear and nonlinear optical response when implanted samples were subsequently annealed at temperatures from 500 to 1000 C in argon and oxygen atmospheres. The annealing effect on optical properties is found to be strongly dependent on the annealing atmospheres. Our results indicate that annealing treatment in O 2 affects the local environment of the implanted metal ions and hence the linear and nonlinear optical properties of the metal-dielectric composite. We suggest that a new phase of metal-oxygen-silicate was formed during annealing in O 2 atmosphere.

  16. A density-functional study on the electronic and vibrational properties of layered antimony telluride.

    PubMed

    Stoffel, Ralf P; Deringer, Volker L; Simon, Ronnie E; Hermann, Raphaël P; Dronskowski, Richard

    2015-03-04

    We present a comprehensive survey of electronic and lattice-dynamical properties of crystalline antimony telluride (Sb2Te3). In a first step, the electronic structure and chemical bonding have been investigated, followed by calculations of the atomic force constants, phonon dispersion relationships and densities of states. Then, (macroscopic) physical properties of Sb2Te3 have been computed, namely, the atomic thermal displacement parameters, the Grüneisen parameter γ, the volume expansion of the lattice, and finally the bulk modulus B. We compare theoretical results from three popular and economic density-functional theory (DFT) approaches: the local density approximation (LDA), the generalized gradient approximation (GGA), and a posteriori dispersion corrections to the latter. Despite its simplicity, the LDA shows excellent performance for all properties investigated-including the Grüneisen parameter, which only the LDA is able to recover with confidence. In the absence of computationally more demanding hybrid DFT methods, the LDA seems to be a good choice for further lattice dynamical studies of Sb2Te3 and related layered telluride materials.

  17. Semiconductor nanocrystals functionalized with antimony telluride zintl ions for nanostructured thermoelectrics.

    PubMed

    Kovalenko, Maksym V; Spokoyny, Boris; Lee, Jong-Soo; Scheele, Marcus; Weber, Andrew; Perera, Susanthri; Landry, Daniel; Talapin, Dmitri V

    2010-05-19

    The energy efficiency of heat engines could be improved by the partial recovery of waste heat using thermoelectric (TE) generators. We show the possibility of designing nanostructured TE materials using colloidal inorganic nanocrystals functionalized with molecular antimony telluride complexes belonging to the family of Zintl ions. The unique advantage of using Zintl ions as the nanocrystal surface ligands is the possibility to convert them into crystalline metal chalcogenides, thus linking individual nanobuilding blocks into a macroscopic assembly of electronically coupled functional modules. This approach allows preserving the benefits of nanostructuring and quantum confinement while enabling facile charge transport through the interparticle boundaries. A developed methodology was applied for solution-based fabrication of nanostructured n- and p-type Bi(2-x)Sb(x)Te(3) alloys with tunable composition and PbTe-Sb(2)Te(3) nanocomposites with controlled grain size. Characterization of the TE properties of these materials showed that their Seebeck coefficients, electrical and thermal conductivities, and ZT values compared favorably with those of previously reported solution-processed TE materials.

  18. Inkjet-printing of antimony-doped tin oxide (ATO) films for transparent conducting electrodes.

    PubMed

    Lim, Jongwoo; Jeong, Bong Yong; Yoon, Ho Gyu; Lee, Sung-Nam; Kim, Jihoon

    2012-02-01

    Antimony-doped Tin oxide (ATO) films have been prepared by inkjet-printing method using ATO nanoparticle inks. The electrical and optical properties of the ATO films were investigated in order to understand the effects of rapid thermal annealing (RTA) temperatures. The decrease in the sheet resistance and resistivity of the inkjet-printed ATO films was observed as the annealing temperature increased. The film annealed at 700 degrees C showed the sheet resistance of 1.7 x 10(3) Omega/sq with the film thickness of 350 nm. The optical transmittance of the films remained constant regardless of their annealing temperatures. In order to further reduce the sheet resistance of the films as well as the annealing temperature, Ag-grid was printed in between two layers of inkjet-printed ATO. With 1.5 mm Ag line spacing, the Ag-grid embedded ATO film showed the sheet resistance of 25.6 Omega/sq after RTA at 300 degrees C.

  19. Speciation and bioavailability of selenium and antimony in non-flooded and wetland soils: a review.

    PubMed

    Nakamaru, Yasuo M; Altansuvd, Javkhlantuya

    2014-09-01

    Studies on the sorption behaviors of selenium (Se) and antimony (Sb) are reviewed. Both Se and Sb chemical speciation can be controlled by pH and redox potential, and both of them are likely to be sorbed onto oxy-hydroxides of aluminum, iron or manganese in soils. For agricultural soils especially, there are important physico-chemical and biological differences between non-flooded and wetland soils. Se forms Se(VI), Se(IV), Se(0), Se(-II), and organic Se species at soil pH and redox conditions. Under non-flooded conditions Se solubility is governed by an adsorption mechanism onto metal oxy-hydroxides rather than by precipitation and dissolution reactions; however, for the conditions of wetland soils, it can be expected that Se(0) and organic matter-bound Se play an important role. For Sb, in the soil environment, the dominant Sb forms are Sb(III) and Sb(V). Under aerobic soil conditions, Sb(III) is likely to be oxidized to Sb(V), and the dominant sorbed Sb species should be Sb(V). Under reducing conditions Sb mobility should be lower than under oxidizing conditions due to the lower mobility of Sb(III); however, reduction of Fe and Mn oxides could lead to dissolution of Fe and Mn-bound Sb. This indicates that the risk of Sb contamination to the food chain could be increased in wetland systems.

  20. Assessment and distribution of antimony in soils around three coal mines, Anhui, China.

    PubMed

    Qi, Cuicui; Liu, Guijian; Kang, Yu; Lam, Paul K S; Chou, Chenlin

    2011-08-01

    Thirty-three soil samples were collected from the Luling, Liuer, and Zhangji coal mines in the Huaibei and Huainan areas of Anhui Province, China. The samples were analyzed for antimony (Sb) by inductively coupled plasma-optical emission spectrometry (ICP-OES) method. The average Sb content in the 33 samples was 4 mg kg(-1), which is lower than in coals from this region (6.2 mg kg(-1)). More than 75% of the soils sampled showed a significant degree of Sb pollution (enrichment factors [EFs] 5-20). The soils collected near the gob pile and coal preparation plant were higher in Sb content than those collected from residential areas near the mines. The gob pile and tailings from the preparation plant were high in mineral matter content and high in Sb. They are the sources of Sb pollution in surface soils in the vicinity of coal mines. The spatial dispersion of Sb in surface soil in the mine region shows that Sb pollution could reach out as far as 350 m into the local environment conditions. Crops in rice paddies may adsorb some Sb and reduce the Sb content in soils from paddyfields. Vertical distribution of Sb in two soil profiles indicates that Sb is normally relatively immobile in soils.

  1. High levels of antimony in dust from e-waste recycling in southeastern China.

    PubMed

    Bi, Xiangyang; Li, Zhonggen; Zhuang, Xiaochun; Han, Zhixuan; Yang, Wenlin

    2011-11-01

    Environmental contamination due to uncontrolled e-waste recycling is an emerging global issue. Antimony (Sb) is a toxic element used in semiconductor components and flame retardants for circuit board within electronic equipment. When e-waste is recycled, Sb is released and contaminates the surrounding environment; however, few studies have characterized the extent of this problem. In this study, we investigated Sb and arsenic (As) distributions in indoor dust from 13 e-waste recycling villages in Guiyu, Guangdong Province, southeastern China. Results revealed significantly elevated concentrations of Sb (6.1-232 mg/kg) in dust within all villages, which were 3.9-147 times higher than those from the non e-waste sites, indicating e-waste recycling was an important source of Sb pollution. On the contrary, As concentrations (5.4-17.7 mg/kg) in e-waste dusts were similar to reference values from the control sites. Therefore, dusts emitted from e-waste recycling may be characterized by high Sb/As ratios, which may help identify the contamination due to the e-waste recycling activities.

  2. Effect of antimony addition on the optical behaviour of germanium selenide thin films

    NASA Astrophysics Data System (ADS)

    Sharma, Parikshit; Rangra, V. S.; Sharma, Pankaj; Katyal, S. C.

    2008-11-01

    This paper reports the influence of antimony (Sb) addition on the optical properties (optical energy gap and refractive index) of thin solid films of the chalcogenide glassy Ge0.17Se0.83-xSbx(x = 0, 0.03, 0.09, 0.12, 0.15) system. This has been done by analysing the transmittance (T) and reflectance (R) spectra in the spectral region 400-2000 nm. It was found that the optical energy gap decreases with increasing Sb content from 1.92 to 1.63 eV with an uncertainty of ± 0.01 eV. The results were interpreted in terms of bond energies and on the basis of the concept of electronegativity. The refractive index has been found to increase with increasing Sb content. The increase in the refractive index has been explained on the basis of polarizability. Dispersion of refractive index has been analysed using the Wemple-DiDomenico single oscillator model. The static refractive index increased from 2.45 to 2.91 for the studied compositions. An estimate of the energy gap has also been taken theoretically and it has been found that both the optical energy gap (measured from T and R spectra) and the theoretical energy gap follow similar trends.

  3. A Multiplatform Metabolomic Approach to the Basis of Antimonial Action and Resistance in Leishmania infantum.

    PubMed

    Rojo, David; Canuto, Gisele A B; Castilho-Martins, Emerson A; Tavares, Marina F M; Barbas, Coral; López-Gonzálvez, Ángeles; Rivas, Luis

    2015-01-01

    There is a rising resistance against antimony drugs, the gold-standard for treatment until some years ago. That is a serious problem due to the paucity of drugs in current clinical use. In a research to reveal how these drugs affect the parasite during treatment and to unravel the underlying basis for their resistance, we have employed metabolomics to study treatment in Leishmania infantum promastigotes. This was accomplished first through the untargeted analysis of metabolic snapshots of treated and untreated parasites both resistant and responders, utilizing a multiplatform approach to give the widest as possible coverage of the metabolome, and additionally through novel monitoring of the origin of the detected alterations through a 13C traceability experiment. Our data stress a multi-target metabolic alteration with treatment, affecting in particular the cell redox system that is essential to cope with detoxification and biosynthetic processes. Additionally, relevant changes were noted in amino acid metabolism. Our results are in agreement with other authors studying other Leishmania species.

  4. Influence of combined pollution of antimony and arsenic on culturable soil microbial populations and enzyme activities.

    PubMed

    Wang, Qiongshan; He, Mengchang; Wang, Ying

    2011-01-01

    The effects of both combined and single pollution of antimony (Sb) and arsenic (As) in different concentrations on culturable soil microbial populations and enzyme activities were studied under laboratory conditions. Joint effects of both Sb and As were different from that of Sb or As alone. The inhibition rate of culturable soil microbial populations under Sb and As pollution followed the order: bacterial > fungi > actinomycetes. There existed antagonistic inhibiting effect on urease and acid phophatase and synergistic inhibiting effect on protease under the combined pollution of Sb (III) and As (III). Only urease appeared to be the most sensitive indicator under Sb (V) and As (V) pollution, and there existed antagonistic inhibiting effect on acid phophatase and synergistic inhibiting effect on urease and protease under Sb (V) and As (V) combined pollution at most time. In this study, we also confirmed that the trivalent states of Sb and As were more toxic to all the microbes tested and more inhibitory on microbial enzyme activities then their pentavalent counterparts. The results also suggest that not only the application rate of the two metalloids but also the chemical form of metalloids should be considered while assessing the effect of metalloid on culturable microbial populations and enzyme activities. Urease and acid phosphatase can be used as potential biomarkers to evaluate the intensity of Sb (III) and As (III) stress.

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

    PubMed

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

    2013-12-03

    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.

  6. LETTER: Toroidally asymmetric ELM precursors in TCV

    NASA Astrophysics Data System (ADS)

    Reimerdes, H.; Pochelon, A.; Suttrop, W.

    1998-03-01

    Coherent magnetic oscillations precede edge localized modes (ELMs) in TCV. The precursor has been detected prior to ELMs considered to be of type III and others previously referred to as TCV large ELMs. This permits the identification of both as type III ELMs according to the usual classification scheme. The strong localization of these precursors on the bad curvature side of the plasma and their medium toroidal mode numbers indicate their ballooning character. Unlike conventional MHD modes, these modes start toroidally localized and grow in amplitude and toroidal extent. When the precursor encompasses the whole toroidal circumference, the increased transport phase, as indicated by the characteristic Dα spike, begins.

  7. Synthesis and structures of metal chalcogenide precursors

    NASA Technical Reports Server (NTRS)

    Hepp, Aloysius F.; Duraj, Stan A.; Eckles, William E.; Andras, Maria T.

    1990-01-01

    The reactivity of early transition metal sandwich complexes with sulfur-rich molecules such as dithiocarboxylic acids was studied. Researchers recently initiated work on precursors to CuInSe2 and related chalcopyrite semiconductors. Th every high radiation tolerance and the high absorption coefficient of CuInSe2 makes this material extremely attractive for lightweight space solar cells. Their general approach in early transition metal chemistry, the reaction of low-valent metal complexes or metal powders with sulfur and selenium rich compounds, was extended to the synthesis of chalcopyrite precursors. Here, the researchers describe synthesis, structures, and and routes to single molecule precursors to metal chalcogenides.

  8. Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; determination of antimony by automated-hydride atomic absorption spectrophotometry

    USGS Publications Warehouse

    Brown, G.E.; McLain, B.J.

    1994-01-01

    The analysis of natural-water samples for antimony by automated-hydride atomic absorption spectrophotometry is described. Samples are prepared for analysis by addition of potassium and hydrochloric acid followed by an autoclave digestion. After the digestion, potassium iodide and sodium borohydride are added automatically. Antimony hydride (stibine) gas is generated, then swept into a heated quartz cell for determination of antimony by atomic absorption spectrophotometry. Precision and accuracy data are presented. Results obtained on standard reference water samples agree with means established by interlaboratory studies. Spike recoveries for actual samples range from 90 to 114 percent. Replicate analyses of water samples of varying matrices give relative standard deviations from 3 to 10 percent.

  9. Progress in molecular precursors for electronic materials

    SciTech Connect

    Buhro, W.E.

    1996-09-01

    Molecular-precursor chemistry provides an essential underpinning to all electronic-materials technologies, including photovoltaics and related areas of direct interest to the DOE. Materials synthesis and processing is a rapidly developing field in which advances in molecular precursors are playing a major role. This article surveys selected recent research examples that define the exciting current directions in molecular-precursor science. These directions include growth of increasingly complex structures and stoichiometries, surface-selective growth, kinetic growth of metastable materials, growth of size-controlled quantum dots and quantum-dot arrays, and growth at progressively lower temperatures. Continued progress in molecular-precursor chemistry will afford precise control over the crystal structures, nanostructures, and microstructures of electronic materials.

  10. Biochemical Removal of HAP Precursors From Coal

    SciTech Connect

    Olson, G.; Tucker, L.; Richards, J.

    1997-07-01

    This project addresses DOE`s interest in advanced concepts for controlling emissions of air toxics from coal-fired utility boilers. We are determining the feasibility of developing a biochemical process for the precombustion removal of substantial percentages of 13 inorganic hazardous air pollutant (HAP) precursors from coal. These HAP precursors are Sb, As, Be, Cd, Cr, Cl, Co, F, Pb, Hg, Mn, Ni, and Se. Although rapid physical coal cleaning is done routinely in preparation plants, biochemical processes for removal of HAP precursors from coal potentially offer advantages of deeper cleaning, more specificity, and less coal loss. Compared to chemical processes for coal cleaning, biochemical processes potentially offer lower costs and milder process conditions. Pyrite oxidizing bacteria, most notably Thiobacillusferrooxidans, are being evaluated in this project for their ability to remove HAP precursors from U.S. coals.

  11. Explorations Precursor Robotic Missions (xPRM)

    NASA Video Gallery

    Jay Jenkins delivers a presentation from the Exploration Precursor Robotic Missions (xPRM) study team on May 25, 2010, at the NASA Exploration Enterprise Workshop held in Galveston, TX. The purpose...

  12. First-Line Therapy for Human Cutaneous Leishmaniasis in Peru Using the TLR7 Agonist Imiquimod in Combination with Pentavalent Antimony

    PubMed Central

    Miranda-Verastegui, Cesar; Tulliano, GianFranco; Gyorkos, Theresa W.; Calderon, Wessmark; Rahme, Elham; Ward, Brian; Cruz, Maria; Llanos-Cuentas, Alejandro; Matlashewski, Greg

    2009-01-01

    Background Current therapies for cutaneous leishmaniasis are limited by poor efficacy, long-term course of treatment, and the development of resistance. We evaluated if pentavalent antimony (an anti-parasitic drug) combined with imiquimod (an immunomodulator) was more effective than pentavalent antimony alone in patients who had not previously been treated. Methods A randomized double-blind clinical trial involving 80 cutaneous leishmaniasis patients was conducted in Peru. The study subjects were recruited in Lima and Cusco (20 experimental and 20 control subjects at each site). Experimental arm: Standard dose of pentavalent antimony plus 5% imiquimod cream applied to each lesion three times per week for 20 days. Control arm: Standard dose of pentavalent antimony plus placebo (vehicle cream) applied as above. The primary outcome was cure defined as complete re-epithelization with no inflammation assessed during the 12 months post-treatment period. Results Of the 80 subjects enrolled, 75 completed the study. The overall cure rate at the 12-month follow-up for the intention-to-treat analysis was 75% (30/40) in the experimental arm and 58% (23/40) in the control arm (p = 0.098). Subgroup analyses suggested that combination treatment benefits were most often observed at the Cusco site, where L. braziliensis is the prevalent species. Over the study period, only one adverse event (rash) was recorded, in the experimental arm. Conclusion The combination treatment of imiquimod plus pentavalent antimony performed better than placebo plus pentavalent antimony, but the difference was not statistically significant. Trial Registration Clinical Trials.gov NCT00257530 PMID:19636365

  13. Treatment of antimony-unresponsive Indian visceral leishmaniasis with ultra-short courses of amphotericin-B-lipid complex.

    PubMed

    Sundar, S; Goyal, A K; More, D K; Singh, M K; Murray, H W

    1998-10-01

    High cost is the principal drawback of treating visceral leishmaniasis (VL; kala-azar) with any of the new lipid formulations of amphotericin B. The aim of the present study was to see if the costs of treatment with such drugs could be reduced by using ultra-short courses. Amphotericin-B-lipid complex (ABLC) was given to 77 Indian patients with antimony-unresponsive VL, either as a single infusion of 5 mg/kg (Group A) or two infusions, each of 5 mg/kg, given 5 days apart (Group B) or on consecutive days (Group C). Other than the anticipated higher fever and chills, treatment was well-tolerated. On day 19 after first infusion, 72 patients were considered apparent cures: 24 (89%) of the 27 in Group A; all 24 (100%) in Group B; and 24 (92%) of the 26 patients in Group C. Six months after treatment, 19 (70%) of 27 in Group A, 19 (79%) of 24 in Group B, and 21 (81%) of 26 in Group C were healthy, relapse-free and considered definitive cures. These cure rates were not statistically different. All 18 treatment failures (five initial non-responders and 13 relapses) were cured after treatment with a 5-day course of ABLC at a higher dose (10-15 mg/kg.day). In a related analysis of hospital plus drug costs for treating antimony-unresponsive VL, short-course ABLC (1-5 days) was compared with conventional amphotericin B (0.75-1.0 mg/kg on alternate days over 30-34 days). This analysis, which included the cost of re-treatment, identified one short-course ABLC regimen with an overall estimated expense which was only modestly higher than that of amphotericin B. Together, the present results provide further support for the use of ABLC in the management of VL patients who fail antimony therapy.

  14. Clinical and Parasitological Features of Patients with American Cutaneous Leishmaniasis that Did Not Respond to Treatment with Meglumine Antimoniate

    PubMed Central

    Robayo, Marta L.; Lopez, Myriam C.; Daza, Carlos D.; Bedoya, Angela; Mariño, Maria L.; Saavedra, Carlos H.

    2016-01-01

    Background American cutaneous leishmaniasis (ACL) is a complicated disease producing about 67.000 new cases per year. The severity of the disease depends on the parasite species; however in the vast majority of cases species confirmation is not feasible. WHO suggestion for ACL produced by Leishmania braziliensis, as first line treatment, are pentavalent antimonial derivatives (Glucantime or Sodium Stibogluconate) under systemic administration. According to different authors, pentavalent antimonial derivatives as treatment for ACL show a healing rate of about 75% and reasons for treatment failure are not well known. Methods In order to characterise the clinical and parasitological features of patients with ACL that did not respond to Glucantime, a cross-sectional observational study was carried out in a cohort of 43 patients recruited in three of the Colombian Army National reference centers for complicated ACL. Clinical and paraclinical examination, and epidemiological and geographic information were recorded for each patient. Parasitological, histopathological and PCR infection confirmation were performed. Glucantime IC50 and in vitro infectivity for the isolated parasites were estimated. Results Predominant infecting Leishmania species corresponds to L. braziliensis (95.4%) and 35% of the parasites isolated showed a significant decrease in in vitro Glucanatime susceptibility associated with previous administration of the medicament. Lesion size and in vitro infectivity of the parasite are negatively correlated with decline in Glucantime susceptibility (Spearman: r = (-)0,548 and r = (-)0,726; respectively). Conclusion A negative correlation between lesion size and parasite resistance is documented. L. braziliensis was found as the main parasite species associated to lesion of patients that underwent treatment failure or relapse. The indication of a second round of treatment in therapeutic failure of ACL, produced by L. braziliensis, with pentavalent antimonial

  15. Hydridosiloxanes as precursors to ceramic products

    DOEpatents

    Blum, Y.D.; Johnson, S.M.; Gusman, M.I.

    1997-06-03

    A method is provided for preparing ceramic precursors from hydridosiloxane starting materials and then pyrolyzing these precursors to give rise to silicious ceramic materials. Si-H bonds present in the hydridosiloxane starting materials are catalytically activated, and the activated hydrogen atoms may then be replaced with nonhydrogen substituents. These preceramic materials are pyrolyzed in a selected atmosphere to give the desired ceramic product. Ceramic products which may be prepared by this technique include silica, silicon oxynitride, silicon carbide, metal silicates, and mullite.

  16. Uptake, translocation and transformation of antimony in rice (Oryza sativa L.) seedlings.

    PubMed

    Cai, Fei; Ren, Jinghua; Tao, Shu; Wang, Xilong

    2016-02-01

    Antimony (Sb), as a toxic metalloid, has been gaining increasing research concerns due mainly to its severe pollution in many places. Rice has been identified to be the dominant intake route of Sb by residents close to the Sb mining areas. A hydroponic experiment was conducted to investigate the difference in uptake, translocation and transformation of Sb in rice seedlings of four cultivars exposed to 0.2 or 1.0 mg/L of Sb(V). The results showed that mass concentration of iron plaque (mg/kg FW) formed at the root surfaces of cultivar N was the highest among all tested cultivars at both low and high exposure levels of Sb(V). The accumulated Sb concentration in iron plaque significantly increased with an increase in mass concentration of iron plaque formed at the rice root. The total amount of iron plaque (mg/pot) at rice root generally increased with increasing exposed Sb(V) concentration, which was closely associated with the increasing lipid peroxidation in roots. Concentration percentage of Sb in rice root significantly reduced as the corresponding value in the iron plaque increased, suggesting that iron plaque formation strongly suppressed uptake of Sb by rice root. Sb concentration in rice tissues followed an order: root > stem, leaf. The japonica rice (cultivars N and Z) exhibited a stronger translocation tendency of Sb from root to stem than indica hybrid rice (cultivars F and G). Translocation of Sb from root of cultivar F to its stem and leaf was sharply enhanced with increasing Sb exposure concentration. Sb(V) could be reduced to Sb(III) in rice tissues, especially in stems (10-26% of the total Sb). For the sake of food safety, the difference in uptake, translocation and transformation of Sb in rice species planted in Sb-contaminated soils should be taken into consideration.

  17. Records of anthropogenic antimony in the glacial snow from the southeastern Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Zhang, Yulan; Kang, Shichang; Chen, Pengfei; Li, Xiaofei; Liu, Yajun; Gao, Tanguang; Guo, Junming; Sillanpää, Mika

    2016-12-01

    Antimony (Sb) is a ubiquitous element in the environment that is potentially toxic at very low concentrations. In this study, surface snow/ice and snowpit samples were collected from four glaciers in the southeastern Tibetan Plateau in June 2015. The concentrations of Sb and other elements were measured in these samples. The results showed that the average concentration of Sb was approximately 2.58 pg g-1 with a range of 1.64-9.20 pg g-1. The average Sb concentration in the study area was comparable to that recorded in a Mt. Everest ice core and higher than that in Arctic and Antarctic snow/ice but much lower than that in Tien Shan and Alps ice cores. Sb presented different variations with other toxic elements (Pb and Cr) and a crustal element (Al) in the three snowpits, which indicated the impact of a different source or post-deposition processes. The enrichment factor of Sb was larger than 10, suggesting that anthropogenic sources provided important contributions to Sb deposition in the glaciers. The Sb in the glacial snow was mainly loaded in the fourth component in principal component analysis, exhibiting discrepancies with crustal elements (Fe and Ca) and other toxic metals (Pb). Backward trajectories revealed that the air mass arriving at the southeastern Tibetan Plateau mostly originated from the Bay of Bengal and the South Asia in June. Thus, pollutants from the South Asia could play an important role in Sb deposition in the studied region. The released Sb from glacier meltwater in the Tibetan Plateau and surrounding areas might pose a risk to the livelihoods and well-being of those in downstream regions.

  18. TiO2 crystal facet-dependent antimony adsorption and photocatalytic oxidation.

    PubMed

    Song, Jiaying; Yan, Li; Duan, Jinming; Jing, Chuanyong

    2017-02-24

    Anatase TiO2 crystal facets are garnering increasing attention due to their unique surface property. However, no specific linear relationship had been derived between the facet exposed on TiO2 and the surface adsorption capacity as well as photocatalytic performance. This study systematically explored the facet effects on antimony (Sb) adsorption and photocatalytic oxidation using high-index {201} and low-index {101}, {001}, and {100} TiO2. The results suggest that high-index {201} TiO2 exhibits the best Sb(III) adsorption and photocatalytic activity compared to the low-index TiO2. Both the Sb(III) adsorption density and the amount of OH and O2(-) generated in solution were correlated to the magnitude of surface energy on TiO2 facets. Photocatalytically generated OH and O2(-) were responsible for Sb(III) photooxidation as evidenced by radical-trapping experiments. The great contribution of OH was observed only on {201}, not on low-index TiO2. This phenomenon was found to be attributable to the high surface energy on {201}, which enables the generation of a large amount of photogeneration OH to compensate for the fast rate of OH dissipation. Therefore, the predominant participation of OH in Sb(III) photooxidation was only possible on high-index {201} TiO2, which resulted in an enhanced photocatalytic rate. On the other hand, O2(-) dominated the Sb(III) photocatalytic oxidation on low-index TiO2. The intrinsic facet-dependent adsorption and photocatalytic mechanism obtained from this study would be useful for developing TiO2-based environmental technologies.

  19. Reduced Graphene Oxide/Tin-Antimony Nanocomposites as Anode Materials for Advanced Sodium-Ion Batteries.

    PubMed

    Ji, Liwen; Zhou, Weidong; Chabot, Victor; Yu, Aiping; Xiao, Xingcheng

    2015-11-11

    Reduced graphene oxides loaded with tin-antimony alloy (RGO-SnSb) nanocomposites were synthesized through a hydrothermal reaction and the subsequent thermal reduction treatments. Transmission electron microscope images confirm that SnSb nanoparticles with an average size of about 20-30 nm are uniformly dispersed on the RGO surfaces. When they were used as anodes for rechargeable sodium (Na)-ion batteries, these as-synthesized RGO-SnSb nanocomposite anodes delivered a high initial reversible capacity of 407 mAh g(-1), stable cyclic retention for more than 80 cycles and excellent cycle stability at ultra high charge/discharge rates up to 30C. The significantly improved performance of the synthesized RGO-SnSb nanocomposites as Na-ion battery anodes can be attributed to the synergetic effects of RGO-based flexible framework and the nanoscale dimension of the SnSb alloy particles (<30 nm). Nanosized intermetallic SnSb compounds can exhibit improved structural stability and conductivity during charge and discharge reactions compared to the corresponding individuals (Sn and Sb particles). In the meantime, RGO sheets can tightly anchor SnSb alloy particles on the surfaces, which can not only effectively suppress the agglomeration of SnSb particles but also maintain excellent electronic conduction. Furthermore, the mechanical flexibility of the RGO phase can accommodate the volume expansion and contraction of SnSb particles during the prolonged cycling, therefore, improve the electrode integrity mechanically and electronically. All of these contribute to the electrochemical performance improvements of the RGO-SnSb nanocomposite-based electrodes in rechargeable Na-ion batteries.

  20. Co-leaching of brominated compounds and antimony from bottled water.

    PubMed

    Andra, Syam S; Makris, Konstantinos C; Shine, James P; Lu, Chensheng

    2012-01-01

    A fast-growing bottled water market is occasionally challenged by reports calling for contaminant leaching from water-contact materials (plastics). Our focus was on leaching of antimony (Sb) and brominated compounds expressed by total soluble bromine (Br) measurements, including those of polybrominated diphenyl ethers (PBDE). Studies are lacking on concomitant leaching of two or more inorganic plastic constituents from the same bottle. A market-representative basket survey of bottled water was initiated in Boston, USA supermarkets. Bottled water classes sampled were: i) non-carbonated (NCR), ii) carbonated (CR), and iii) non-carbonated and enriched (NCRE). Plastic bottle materials sampled were: polyethylene terephthalate (PET), high-density polyethylene (HDPE), polystyrene (PS), and polycarbonate (PC). Storage conditions for the 31 bottled water samples were: 23°C temperature, no-shaking and 12h/12h light/dark for 60days of equilibration. Average Br and Sb concentrations after 60-days of storage followed the order of NCR

  1. Antimony and arsenic leaching from secondary lead smelter air-pollution-control residues.

    PubMed

    Ettler, Vojtech; Mihaljevic, Martin; Sebek, Ondrej

    2010-07-01

    Environments in the vicinity of the lead (Pb) smelters are contaminated by emissions containing high concentrations of antimony (Sb) and arsenic (As). Air-pollution-control (APC) residues from bag-type filters from a secondary Pb smelter were subjected to leaching experiments to elucidate the controlling mechanisms of Sb and As release. Kinetic batch leaching tests at a liquid-to-solid (L/S) ratio of 10 L kg(- 1) within the time frame of 720 hours and batch leaching at various L/S ratios (ranging from 1 to 1000 L kg(-1)) were performed. In contrast to other inorganic contaminants (Pb, Cd, Zn), less than 1% of the total Sb and As content was leached from the residues. At a L/S ratio of 10, the As and Sb concentrations in the leachates exceeded the EU limit values for non-hazardous waste (0.2 and 0.07 mg L(-1) ). According to PHREEQC-2 calculations, the concentrations of As and Sb are controlled by the precipitation of complex arsenates and antimonates mainly at low L/S ratios. The washing and related chemical/mineralogical transformation of APC residues was suggested as a technological pre-treatment process before their re-smelting in a blast furnace. The Ferrox-like processing of the resulting contaminated process water/leachate was simulated using the PHREEQC-2 code. Significant reduction was obtained in the concentration of some key contaminants (As, Cu, Pb, Zn) related to sorption on newly formed hydrous ferric oxides, whereas Sb and Cd exhibited only limited attenuation.

  2. Association of drinking-water source and use characteristics with urinary antimony concentrations.

    PubMed

    Makris, Konstantinos C; Andra, Syam S; Herrick, Lisa; Christophi, Costas A; Snyder, Shane A; Hauser, Russ

    2013-03-01

    Environmental factors, such as storage time, frequency of bottle reuse and temperature, have been shown to facilitate antimony (Sb) leaching from water- and food-packaging materials. The globally escalating consumption of water packaged in Sb-containing bottles, such as that of polyethylene terephthalate (PET), could increase human daily Sb doses. This study set out to investigate the relationship between drinking-water source, use characteristics, and urinary Sb concentrations (U-Sb) accompanied with survey responses of a healthy (n=35) Cypriot participant pool. One spot urine sample was collected during administration of questionnaire, while a second spot urine sample was collected from the same individual about 7 days later. Urinary and water Sb concentrations were measured with an inductively coupled plasma mass spectrometer. Survey responses showed that bottled water summed over various volumes and plastic types, such as polycarbonate and PET contributed to an average 61% of daily water consumption. Water sources such as tap, mobile stations (explained in a following section), and well water contributed to 24%, 14%, and 2% of an individual's daily water consumption pattern, respectively. Average daily potable water use of both bottled and tap water by individuals consisted of 65% drinking-water, while the remaining 35% was water used for preparing cold and hot beverages, such as, tea, coffee, and juices. A significant (P=0.02) association between per capita water consumption from PET bottles and urinary creatinine-unadjusted concentrations was observed, but this relationship did not remain after inclusion of covariates in a multivariate regression model. In the creatinine-adjusted regression model, only gender (female) was a significant (P<0.01) predictor of U-Sb, after adjusting for several covariates. It is proposed that consumption data collection on various water uses and sources among individuals could perhaps decrease the uncertainty associated with

  3. Depth-resolved microbial community analyses in two contrasting soil cores contaminated by antimony and arsenic.

    PubMed

    Xiao, Enzong; Krumins, Valdis; Xiao, Tangfu; Dong, Yiran; Tang, Song; Ning, Zengping; Huang, Zhengyu; Sun, Weimin

    2017-02-01

    Investigation of microbial communities of soils contaminated by antimony (Sb) and arsenic (As) is necessary to obtain knowledge for their bioremediation. However, little is known about the depth profiles of microbial community composition and structure in Sb and As contaminated soils. Our previous studies have suggested that historical factors (i.e., soil and sediment) play important roles in governing microbial community structure and composition. Here, we selected two different types of soil (flooded paddy soil versus dry corn field soil) with co-contamination of Sb and As to study interactions between these metalloids, geochemical parameters and the soil microbiota as well as microbial metabolism in response to Sb and As contamination. Comprehensive geochemical analyses and 16S rRNA amplicon sequencing were used to shed light on the interactions of the microbial communities with their environments. A wide diversity of taxonomical groups was present in both soil cores, and many were significantly correlated with geochemical parameters. Canonical correspondence analysis (CCA) and co-occurrence networks further elucidated the impact of geochemical parameters (including Sb and As contamination fractions and sulfate, TOC, Eh, and pH) on vertical distribution of soil microbial communities. Metagenomes predicted from the 16S data using PICRUSt included arsenic metabolism genes such as arsenate reductase (ArsC), arsenite oxidase small subunit (AoxA and AoxB), and arsenite transporter (ArsA and ACR3). In addition, predicted abundances of arsenate reductase (ArsC) and arsenite oxidase (AoxA and AoxB) genes were significantly correlated with Sb contamination fractions, These results suggest potential As biogeochemical cycling in both soil cores and potentially dynamic Sb biogeochemical cycling as well.

  4. Antimony (Sb) contaminated shooting range soil: Sb mobility and immobilization by soil amendments.

    PubMed

    Okkenhaug, Gudny; Amstätter, Katja; Lassen Bue, Helga; Cornelissen, Gerard; Breedveld, Gijs D; Henriksen, Thomas; Mulder, Jan

    2013-06-18

    Antimony (Sb) in lead bullets poses a major environmental risk in shooting range soils. Here we studied the effect of iron (Fe)-based amendments on the mobility of Sb in contaminated soil from shooting ranges in Norway. Untreated soil showed high Sb concentrations in water extracts from batch tests (0.22-1.59 mg L(-1)) and soil leachate from column tests (0.3-0.7 mg L(-1)), occurring exclusively as Sb(V). Sorption of Sb to different iron-based sorbents was well described by the Freundlich equation (Fe2(SO4)3, log KF = 6.35, n = 1.51; CFH-12 (Fe oxyhydroxide), log KF = 4.16-4.32, n = 0.75-0.76); Fe(0) grit, log KF = 3.26, n = 0.47). These sorbents mixed with soil (0.5 and 2% w/w), showed significant sorption of Sb in batch tests (46-92%). However, for Fe2(SO4)3 and CFH-12 liming was also necessary to prevent mobilization of lead, copper, and zinc. Column tests showed significant retention of Sb (89-98%) in soil amended with CFH-12 (2%) mixed with limestone (1%) compared to unamended soil. The sorption capacity of soils amended with Fe(0) (2%) increased steadily up to 72% over the duration period of the column test (64 days), most likely due to the gradual oxidation of Fe(0) to Fe oxyhydroxides. Based on the experimental results, CFH-12 and oxidized Fe(0) are effective amendments for the stabilization of Sb in shooting range soils.

  5. Correlation Models between Environmental Factors and Bacterial Resistance to Antimony and Copper

    PubMed Central

    Shi, Zunji; Cao, Zhan; Qin, Dong; Zhu, Wentao; Wang, Qian; Li, Mingshun; Wang, Gejiao

    2013-01-01

    Antimony (Sb) and copper (Cu) are toxic heavy metals that are associated with a wide variety of minerals. Sb(III)-oxidizing bacteria that convert the toxic Sb(III) to the less toxic Sb(V) are potentially useful for environmental Sb bioremediation. A total of 125 culturable Sb(III)/Cu(II)-resistant bacteria from 11 different types of mining soils were isolated. Four strains identified as Arthrobacter, Acinetobacter and Janibacter exhibited notably high minimum inhibitory concentrations (MICs) for Sb(III) (>10 mM),making them the most highly Sb(III)-resistant bacteria to date. Thirty-six strains were able to oxidize Sb(III), including Pseudomonas-, Comamonas-, Acinetobacter-, Sphingopyxis-, Paracoccus- Aminobacter-, Arthrobacter-, Bacillus-, Janibacter- and Variovorax-like isolates. Canonical correspondence analysis (CCA) revealed that the soil concentrations of Sb and Cu were the most obvious environmental factors affecting the culturable bacterial population structures. Stepwise linear regression was used to create two predictive models for the correlation between soil characteristics and the bacterial Sb(III) or Cu(II) resistance. The concentrations of Sb and Cu in the soil was the significant factors affecting the bacterial Sb(III) resistance, whereas the concentrations of S and P in the soil greatly affected the bacterial Cu(II) resistance. The two stepwise linear regression models that we derived are as follows: and [where the MICSb(III) and MICCu(II) represent the average bacterial MIC for the metal of each soil (µM), and the CSb, CCu, CS and CP represent concentrations for Sb, Cu, S and P (mg/kg) in soil, respectively, p<0.01]. The stepwise linear regression models we developed suggest that metals as well as other soil physicochemical parameters can contribute to bacterial resistance to metals. PMID:24205252

  6. Molecular characterization of the MRPA transporter and antimony uptake in four New World Leishmania spp. susceptible and resistant to antimony☆

    PubMed Central

    Moreira, Douglas S.; Monte Neto, Rubens L.; Andrade, Juvana M.; Santi, Ana Maria M.; Reis, Priscila G.; Frézard, Frédéric; Murta, Silvane M.F.

    2013-01-01

    ATP-binding cassette (ABC) transporters have been associated with drug resistance in various diseases. The MRPA gene, a transporter of ABCC subfamily, is involved in the resistance by sequestering metal-thiol conjugates in intracellular vesicles of Leishmania parasite. In this study, we performed the molecular characterization of the MRPA transporter, analysis of P-glycoprotein (Pgp) and aquaglyceroporin-1 (AQP1) expression, and determination of antimony level in antimony-susceptible and -resistant lines of L. (V.) guyanensis, L. (L.) amazonensis, L. (V.) braziliensis and L. (L.) infantum. PFGE analysis revealed an association of chromosomal amplification of MRPA gene with the drug resistance phenotype in all SbIII-resistant Leishmania lines analyzed. Levels of mRNA from MRPA gene determined by real-time quantitative RT-PCR showed an increased expression of two fold in SbIII-resistant lines of Leishmania guyanensis, Leishmania amazonensis and Leishmania braziliensis. Western blot analysis revealed that Pgp is increased in the SbIII-resistant L. guyanensis and L. amazonensis lines. The intracellular level of antimony quantified by graphite furnace atomic absorption spectrometry showed a reduction in the accumulation of this element in SbIII-resistant L. guyanensis, L. amazonensis and L. braziliensis lines when compared to their susceptible counterparts. Interestingly, a down-regulation of AQP1 protein was observed in the SbIII-resistant L. guyanensis and L. amazonensis lines, contributing for decreasing of SbIII entry in these lines. In addition, efflux experiments revealed that the rates of SbIII efflux are higher in the SbIII-resistant lines of L. guyanensis and L. braziliensis, that may explain also the low SbIII concentration within of these parasites. The BSO, an inhibitor of γ-glutamylcysteine synthetase enzyme, reversed the SbIII-resistance phenotype of L. braziliensis and caused an increasing in the Sb intracellular level in the LbSbR line. Our data

  7. Arsenic Exposure and Outcomes of Antimonial Treatment in Visceral Leishmaniasis Patients in Bihar, India: A Retrospective Cohort Study

    PubMed Central

    Perry, Meghan R.; Prajapati, Vijay K.; Menten, Joris; Raab, Andrea; Feldmann, Joerg; Chakraborti, Dipankar; Sundar, Shyam; Fairlamb, Alan H.; Boelaert, Marleen; Picado, Albert

    2015-01-01

    Background In the late twentieth century, emergence of high rates of treatment failure with antimonial compounds (SSG) for visceral leishmaniasis (VL) caused a public health crisis in Bihar, India. We hypothesize that exposure to arsenic through drinking contaminated groundwater may be associated with SSG treatment failure due to the development of antimony-resistant parasites. Methods A retrospective cohort design was employed, as antimony treatment is no longer in routine use. The study was performed on patients treated with SSG between 2006 and 2010. Outcomes of treatment were assessed through a field questionnaire and treatment failure used as a proxy for parasite resistance. Arsenic exposure was quantified through analysis of 5 water samples from within and surrounding the patient’s home. A logistic regression model was used to evaluate the association between arsenic exposure and treatment failure. In a secondary analysis survival curves and Cox regression models were applied to assess the risk of mortality in VL patients exposed to arsenic. Results One hundred and ten VL patients treated with SSG were analysed. The failure rate with SSG was 59%. Patients with high mean local arsenic level had a non-statistically significant higher risk of treatment failure (OR = 1.78, 95% CI: 0.7–4.6, p = 0.23) than patients using wells with arsenic concentration <10 μg/L. Twenty one patients died in our cohort, 16 directly as a result of VL. Arsenic levels ≥ 10 μg/L increased the risk of all-cause (HR 3.27; 95% CI: 1.4–8.1) and VL related (HR 2.65; 95% CI: 0.96–7.65) deaths. This was time dependent: 3 months post VL symptom development, elevated risks of all-cause mortality (HR 8.56; 95% CI: 2.5–29.1) and of VL related mortality (HR 9.27; 95% CI: 1.8–49.0) were detected. Discussion/Conclusion This study indicates a trend towards increased treatment failure in arsenic exposed patients. The limitations of the retrospective study design may have masked a strong

  8. Spectral-luminescent properties of silver molecular clusters and nanoparticles formed by ion exchange in antimony-doped photo-thermo-refractive glasses

    NASA Astrophysics Data System (ADS)

    Sgibnev, E. M.; Nikonorov, N. V.; Ignat'ev, A. I.

    2017-01-01

    The formation of silver molecular clusters and nanoparticles in photo-thermo-refractive (PTR) glasses with different antimony contents has been investigated using ion exchange with subsequent thermal treatment. The influence of the antimony oxide (Sb2O3) concentration and treatment temperature on the spectral-luminescent properties of silver molecular clusters and nanoparticles in glass has been investigated. It is shown that silver molecular clusters in PTR glasses are characterized by strong broadband luminescence in the visible and near-IR ranges and that the formation of silver nanoparticles leads to luminescence quenching.

  9. SYSTEM OPTIMIZATION FOR THE AUTOMATIC SIMULTANEOUS DETERMINATION OF ARSENIC, SELENIUM, AND ANTIMONY, USING HYDRIDE GENERATION INTRODUCTION TO AN INDUCTIVELY COUPLED PLASMA.

    USGS Publications Warehouse

    Pyen, Grace S.; Browner, Richard F.; Long, Stephen

    1986-01-01

    A fixed-size simplex has been used to determine the optimum conditions for the simultaneous determination of arsenic, selenium, and antimony by hydride generation and inductively coupled plasma emission spectrometry. The variables selected for the simplex were carrier gas flow rate, rf power, viewing height, and reagent conditions. The detection limit for selenium was comparable to the preoptimized case, but there were twofold and fourfold improvements in the detection limits for arsenic and antimony, respectively. Precision of the technique was assessed with the use of artificially prepared water samples.

  10. Evaluation of thiosemicarbazone derivative as chelating agent for the simultaneous removal and trace determination of Cd(II) and Pb(II) in food and water samples.

    PubMed

    Koduru, Janardhan Reddy; Lee, Kap Duk

    2014-05-01

    In the present investigation, prepared N-ethyl-3-carbazolecarbaxaldehyde-3-thiosemicarbazone (ECCT) and employed for the simultaneous removal and determination of trace amounts of Cd(II) and Pb(II) from food and water samples. Cd(II) and Pb(II) gave yellow and orange colored complexes with ECCT in acetate buffer at pH 6.0 with λmax, 380 and 440nm, respectively. Both complexes were easily extractable into kerosene at 1:1(M:L) composition. It was in accordance with Beer's law in the range of 0.0-12.0 and 0.0-10.0μgmL(-1) with 0.999 and 0.997 correlation coefficient for Cd(II) and Pb(II) complexes, respectively, indicated a good linearity between the two variables. The molar absorptivity and Sandell's sensitivity were found to be 0.740×10(4)Lmol(-1)cm(-1), 1.52×10(-3)μgcm(-2) for Cd(II) and 1.809×10(4)L mol(-1)cm(-1), 1.15×10(-3)μgcm(-2) for Pb(II). The precision and accuracy of the method was checked for both metal ions by finding the relative standard deviations (n=8), which were 0.689% and 0.443%, with detection limits of 0.00151μgL(-1) and 0.00264μgL(-1) for Cd(II) and Pb(II), respectively. Further validation using certified reference material, NIST 1568b, resulted in determined concentrations of 0.028±0.253μgg(-1) for Cd(II) and 0.046±0.325μgg(-1) for Pb(II). These determined values agree well with the certified values in the reference materials. The interfering effects of various cations and anions were also studied. The proposed method performance was also evaluated in terms of Student 'T' test and Variance 'F' test, which indicated the significance of the present method parameters, as an inter comparison of the experimental values using ICP-OES.

  11. Bulk antimony sulfide with excellent cycle stability as next-generation anode for lithium-ion batteries

    PubMed Central

    Yu, Denis Y. W.; Hoster, Harry E.; Batabyal, Sudip K.

    2014-01-01

    Nanomaterials as anode for lithium-ion batteries (LIB) have gained widespread interest in the research community. However, scaling up and processibility are bottlenecks to further commercialization of these materials. Here, we report that bulk antimony sulfide with a size of 10–20 μm exhibits a high capacity and stable cycling of 800 mAh g−1. Mechanical and chemical stabilities of the electrodes are ensured by an optimal electrode-electrolyte system design, with a polyimide-based binder together with fluoroethylene carbonate in the electrolyte. The polyimide binder accommodates the volume expansion during alloying process and fluoroethylene carbonate suppresses the increase in charge transfer resistance of the electrodes. We observed that particle size is not a major factor affecting the charge-discharge capacities, rate capability and stability of the material. Despite the large particle size, bulk antimony sulfide shows excellent rate performance with a capacity of 580 mAh g−1 at a rate of 2000 mA g−1. PMID:24691396

  12. Targeted gene expression profiling in Leishmania braziliensis and Leishmania guyanensis parasites isolated from Brazilian patients with different antimonial treatment outcomes.

    PubMed

    Torres, Davi Coe; Adaui, Vanessa; Ribeiro-Alves, Marcelo; Romero, Gustavo A S; Arévalo, Jorge; Cupolillo, Elisa; Dujardin, Jean-Claude

    2010-08-01

    In Brazil, cutaneous leishmaniasis represents a serious public health problem, and chemotherapy is an important element of the clinical management of this disease. However, treatment efficacy is variable, a phenomenon that might be due to host and parasite (e.g., drug resistance) factors. To better understand the possible contribution of parasite factors to this phenomenon, we characterised 12 Leishmania braziliensis (LB) and 25 Leishmania guyanensis (LG) isolates collected from patients experiencing different antimonial treatment outcomes. For each isolate, promastigote cultures were grown in duplicate and were harvested at the late-log and stationary phases of growth. The RNA expression profiles of six genes encoding proteins with roles in antimony metabolism (AQP1, MRPA, GSH1, GSH2, TRYR and TDR1) were assessed by means of real-time quantitative PCR. Molecular data were compared to the clinical phenotypes. Within LB, we did not find statistically significant differences in the expression levels of the examined genes among isolates from patients with different treatment outcomes. In LG, GSH1 (encoding gamma-glutamylcysteine synthetase, gamma-GCS) was overexpressed in therapeutic failure isolates regardless of the growth curve phase. This finding reveals the predictive potential of promastigote expression curves for the prognosis of cutaneous leishmaniasis caused by LG in Brazil.

  13. Arsenic, Antimony, Chromium, and Thallium Speciation in Water and Sediment Samples with the LC-ICP-MS Technique

    PubMed Central

    Jabłońska-Czapla, Magdalena

    2015-01-01

    Chemical speciation is a very important subject in the environmental protection, toxicology, and chemical analytics due to the fact that toxicity, availability, and reactivity of trace elements depend on the chemical forms in which these elements occur. Research on low analyte levels, particularly in complex matrix samples, requires more and more advanced and sophisticated analytical methods and techniques. The latest trends in this field concern the so-called hyphenated techniques. Arsenic, antimony, chromium, and (underestimated) thallium attract the closest attention of toxicologists and analysts. The properties of those elements depend on the oxidation state in which they occur. The aim of the following paper is to answer the question why the speciation analytics is so important. The paper also provides numerous examples of the hyphenated technique usage (e.g., the LC-ICP-MS application in the speciation analysis of chromium, antimony, arsenic, or thallium in water and bottom sediment samples). An important issue addressed is the preparation of environmental samples for speciation analysis. PMID:25873962

  14. Treatment of air pollution control residues with iron rich waste sulfuric acid: does it work for antimony (Sb)?

    PubMed

    Okkenhaug, Gudny; Breedveld, Gijs D; Kirkeng, Terje; Lægreid, Marit; Mæhlum, Trond; Mulder, Jan

    2013-03-15

    Antimony (Sb) in air pollution control (APC) residues from municipal solid waste incineration has gained increased focus due to strict Sb leaching limits set by the EU landfill directive. Here we study the chemical speciation and solubility of Sb at the APC treatment facility NOAH Langøya (Norway), where iron (Fe)-rich sulfuric acid (∼3.6M, 2.3% Fe(II)), a waste product from the industrial extraction of ilmenite, is used for neutralization. Antimony in water extracts of untreated APC residues occurred exclusively as pentavalent antimonate, even at low pH and Eh values. The Sb solubility increased substantially at pH<10, possibly due to the dissolution of ettringite (at alkaline pH) or calcium (Ca)-antimonate. Treated APC residues, stored anoxically in the laboratory, simulating the conditions at the NOAH Langøya landfill, gave rise to decreasing concentrations of Sb in porewater, occurring exclusively as Sb(V). Concentrations of Sb decreased from 87-918μgL(-1) (day 3) to 18-69μgL(-1) (day 600). We hypothesize that an initial sorption of Sb to Fe(II)-Fe(III) hydroxides (green rust) and eventually precipitation of Ca- and Fe-antimonates (tripuhyite; FeSbO4) occurred. We conclude that Fe-rich, sulfuric acid waste is efficient to immobilize Sb in APC residues from waste incineration.

  15. Nutritional status in patients with cutaneous leishmaniasis and a study of the effects of zinc supplementation together with antimony treatment

    PubMed Central

    Guzman-Rivero, Miguel; Rojas, Ernesto; Verduguez-Orellana, Aleida; Pardo, Henry; Torrico, Mary Cruz; Cloetens, Lieselotte; Åkesson, Björn; Sejas, Edgar

    2014-01-01

    Background The role of micronutrient status for the incidence and clinical course of cutaneous leishmaniasis is not much studied. Still zinc supplementation in leishmaniasis has shown some effect on the clinical recovery, but the evidence in humans is limited. Objective To compare biochemical nutritional status in cutaneous leishmaniasis patients with that in controls and to study the effects of zinc supplementation for 60 days. Design Twenty-nine patients with cutaneous leishmaniasis were treated with antimony for 20 days. Fourteen of them got 45 mg zinc daily and 15 of them got placebo. Biomarkers of nutritional and inflammatory status and changes in size and characteristics of skin lesions were measured. Results The level of transferrin receptor was higher in patients than in controls but otherwise no differences in nutritional status were found between patients and controls. No significant effects of zinc supplementation on the clinical recovery were observed as assessed by lesion area reduction and characteristics or on biochemical parameters. Conclusions It is concluded that nutritional status was essentially unaffected in cutaneous leishmaniasis and that oral zinc supplementation administered together with intramuscular injection of antimony had no additional clinical benefit. PMID:25397995

  16. The effect of tin and antimony addition on the performance of dual function cracking catalyst (DFCC) mixtures

    SciTech Connect

    Occelli, M.L. ); Naraghi, S.M.; Krishnan, V.; Suib, S.L. )

    1992-05-01

    In 1976, the Phillips Petroleum Company successfully demonstrated that the addition of certain organo-antimony compounds to a metal-contaminated heavy gas oil reduced the deleterious effects that metals such as Ni and V have on gasoline yields, coke, and hydrogen selectivities. Nickel has little effect on the activity of a fluidized cracking catalyst (FCC) but generates large amounts of gases, placing severe demands on capabilities of gas compressors. Marketed by Phillips Petroleum Company. Phil-Ad CA antimony organics have been shown to reduce by 50% gas formation due to metal contaminants, especially nickel. However, Sb, when introduced into a fluidized cracking unit, could reduce and form SbH[sub 3], stibine, that like arsine (AsH[sub 3]) is a highly toxic compound. Procedures for the safe usage of Sb in refining operations have been outlined; when used properly, Sb-containing passivating agents did not generate any detectable stibine. Recently, it has been reported that at microactivity test conditions, the additions of diluents (such as aluminas and layered magnesium silicates) capable of selectively sorbing metal contaminants from gas oils can form dual function cracking catalysts (DFCC) that retain most of their useful cracking activity even in the presence of as much as 1.0-1.5% V. It is the purpose of this paper to report the stability of Sb- and Sn-loaded alumina particles and the effects that the addition of metal passivation compounds such as Sb and Sn have on the performance of DFCC mixtures.

  17. Efficient and versatile catalysis of N-alkylation of heterocyclic amines with alcohols and one-pot synthesis of 2-aryl substituted benzazoles with newly designed ruthenium(II) complexes of PNS thiosemicarbazones.

    PubMed

    Ramachandran, Rangasamy; Prakash, Govindan; Selvamurugan, Sellappan; Viswanathamurthi, Periasamy; Malecki, Jan Grzegorz; Ramkumar, Venkatachalam

    2014-06-07

    Ruthenium(II) carbonyl complexes with phosphine-functionalized PNS type thiosemicarbazone ligands [RuCl(CO)(EPh3)(L)] (1-6) (E = P or As, L = 2-(2-(diphenylphosphino)benzylidene) thiosemicarbazone (PNS-H), 2-(2-(diphenylphosphino)benzylidene)-N-methylthiosemicarbazone (PNS-Me), 2-(2-(diphenylphosphino)benzylidene)-N-phenylthiosemicarbazone (PNS-Ph)) have been synthesized and characterized by elemental analysis and spectroscopy (IR, UV-Vis, (1)H, (13)C, (31)P-NMR) as well as ESI mass spectrometry. The molecular structures of complexes 1, 2 and 6 were identified by means of single-crystal X-ray diffraction analysis. The analysis revealed that all the complexes possess a distorted octahedral geometry with the ligand coordinating in a uni-negative tridentate PNS fashion. All the ruthenium complexes (1-6) were tested as catalyst for N-alkylation of heteroaromatic amines with alcohols. Notably, complex 2 was found to be a very efficient and versatile catalyst towards N-alkylation of a wide range of heterocyclic amines with alcohols. Complex 2 can also catalyze the direct amination of 2-nitropyridine with benzyl alcohol to the corresponding secondary amine. Furthermore, a preliminary examination of performance for N,N-dialkylation of diamine showed promising results, giving good conversion and high selectivity. In addition, N-alkylation of ortho-substituted anilines (-NH2, -OH and -SH) led to the one-pot synthesis of 2-aryl substituted benzimidazoles, benzoxazoles and benzothiazoles, also revealing the catalytic activity of complex 2.

  18. Synthesis, Characterization and Molecular Structures of some Bismuth(III) Complexes with Thiosemicarbazones and Dithiocarbazonic Acid Methylester Derivatives with Activity against Helicobacter Pylori

    PubMed Central

    Diemer, Rolf; Dittes, Uwe; Nuber, Bernhard; Seifried, Volker; Opferkuch, Wolfgang

    1995-01-01

    The reactions of bismuth(III) nitrate pentahydrate and bismuth(III) chloride with heterocyclic thiosemicarbazones and derivatives of dithiocarbazonic acid methylester were used to synthesize the respective bismuth(III) complexes, which could be divided into five groups D-H because of their stoichiometrical properties and their molecular structures. The molecular structure and the near coordination sphere of the bismuth(III) central atom of four representative compounds were determined by single-crystal X-ray studies. Bis[1-azepanyl-4-(2-pyridyl)-2,3-diazapenta-1,3-diene-1-thiolato-N′,N3,S]bismuth(III) nitrate (5) belongs to group D. The two tridentate ligands and the nitrate ion surround the bismuth atom. The best description of the coordination sphere appears to be that of a distorted trigonal dodecahedron with one position occupied by the lone pair of the bismuth atom. Bis[1-azepanyl-4-(2-thienyl)-2,3-diazapenta-1,3-diene-1-thiolato-N3,S]bismuth(III) nitrate (9) is assigned to complex type E. Here, two deprotonated ligand molecules are coordinated to the bismuth(III) central atom as bidentate ligands. The structure of this complex can best be described as a distorted trigonal antiprism with a five-coordinated central atom. The two triangular faces are formed by the atoms S(4), N(6), O(11) and S(3), N(4) and the lone pair of the central atom. The two chelate rings are almost perpendicular to each other. Complex molecules of group F form dimeric units with bichloro-bridged bismuth atoms. The structure of di-μ-chlorobis[1-azepanyl-4-(2-pyridyl)-2,3-diazapenta-1,3-diene-1-thiolato-N′,N3,S-chloro]dibismuth(III) (15) can be described as two six-coordinated bismuth atoms, which are bound together via two bridging chlorine atoms. The two bismuth atoms Bi(1) and Bi(1a) and the two bridging chlorine atoms Cl(2) and Cl(2a) form the Bi2Cl2 plane. The two tridentate ligand molecules coordinate via the same atoms as shown in complex 5. In addition, they form two parallel

  19. Growth, photosynthesis, and defense mechanism of antimony (Sb)-contaminated Boehmeria nivea L.

    PubMed

    Chai, Li-Yuan; Mubarak, Hussani; Yang, Zhi-Hui; Yong, Wang; Tang, Chong-Jian; Mirza, Nosheen

    2016-04-01

    Ramie (Boehmeria nivea L.) is the oldest cash fiber crop in China and is widely grown in antimony (Sb) mining areas. To evaluate the extent of Sb resistance and tolerance, the growth, tolerance index (TI), Sb content in plant parts and in Hoagland solution, bioaccumulation factor (BF), photosynthesis, and physiological changes in Sb-contaminated B. nivea (20, 40, 80, and 200 mg L(-1) Sb) grown hydroponically were investigated. The Sb tolerance and resistance of ramie were clearly revealed by growth inhibition, a TI between 13 and 99 %, non-significant changes in the maximum quantum efficiency of photosystem (F v /F m ), energy-harvesting efficiency (photosystem II (PSII)) and single-photon avalanche diode (SPAD) value, a significant increase in Sb in plant parts, BF >1, and an increase in catalase (CAT) and malondialdehyde (MDA) at 200 mg L(-1) Sb. Under increasing Sb stress, nearly the same non-significant decline in the maximum quantum efficiency of photosystem (F v /F m ), energy-harvesting efficiency (PSII), relative quantum yield of photosystem II (φPSII), and photochemical quenching (qP), except for F v /F m at 20 mg L(-1) Sb, were recorded. SPAD values for chlorophyll under Sb stress showed an increasing trend, except for a slight decrease, i.e., <2 %, than the control SPAD value at 200 mg L(-1) Sb. With a continuous increase in MDA, superoxide dismutase (SOD), peroxidase (POD), and CAT activities were suppressed under Sb addition up to 40 mg L(-1) Sb and the addition of Sb enhanced enzyme production at 80 and 200 mg L(-1) Sb. A continuous decrease in SOD, POD, and CAT up to 40 mg L(-1) Sb and enhancements at ≥80 mg L(-1), along with the continuous enhancement of MDA activity and inhibited biomass production, clearly reveal the roles of these enzymes in detoxifying Sb stress and the defense mechanism of ramie at 80 mg L(-1) Sb. Thus, B. nivea constitutes a promising candidate for Sb phytoremediation at mining sites.

  20. The presence and leachability of antimony in different wastes and waste handling facilities in Norway.

    PubMed

    Okkenhaug, G; Almås, Å R; Morin, N; Hale, S E; Arp, H P H

    2015-11-01

    The environmental behaviour of antimony (Sb) is gathering attention due to its increasingly extensive use in various products, particularly in plastics. Because of this it may be expected that plastic waste is an emission source for Sb in the environment. This study presents a comprehensive field investigation of Sb concentrations in diverse types of waste from waste handling facilities in Norway. The wastes included waste electrical and electronic equipment (WEEE), glass, vehicle fluff, combustibles, bottom ash, fly ash and digested sludge. The highest solid Sb concentrations were found in WEEE and vehicle plastic (from 1238 to 1715 mg kg(-1)) and vehicle fluff (from 34 to 4565 mg kg(-1)). The type of acid used to digest the diverse solid waste materials was also tested. It was found that HNO3:HCl extraction gave substantially lower, non-quantitative yields compared to HNO3:HF. The highest water-leachable concentration for wastes when mixed with water at a 1 : 10 ratio were observed for plastic (from 0.6 to 2.0 mg kg(-1)) and bottom ash (from 0.4 to 0.8 mg kg(-1)). For all of the considered waste fractions, Sb(v) was the dominant species in the leachates, even though Sb(iii) as Sb2O3 is mainly used in plastics and other products, indicating rapid oxidation in water. This study also presents for the first time a comparison of Sb concentrations in leachate at waste handling facilities using both active grab samples and DGT passive samples. Grab samples target the total suspended Sb, whereas DGT targets the sum of free- and other chemically labile species. The grab sample concentrations (from 0.5 to 50 μg L(-1)) were lower than the predicted no-effect concentration (PNEC) of 113 μg L(-1). The DGT concentrations were substantially lower (from 0.05 to 9.93 μg L(-1)) than the grab samples, indicating much of the Sb is present in a non-available colloidal form. In addition, air samples were taken from the chimney and areas within combustible waste incinerators, as

  1. Correlation models between environmental factors and bacterial resistance to antimony and copper.

    PubMed

    Shi, Zunji; Cao, Zhan; Qin, Dong; Zhu, Wentao; Wang, Qian; Li, Mingshun; Wang, Gejiao

    2013-01-01

    Antimony (Sb) and copper (Cu) are toxic heavy metals that are associated with a wide variety of minerals. Sb(III)-oxidizing bacteria that convert the toxic Sb(III) to the less toxic Sb(V) are potentially useful for environmental Sb bioremediation. A total of 125 culturable Sb(III)/Cu(II)-resistant bacteria from 11 different types of mining soils were isolated. Four strains identified as Arthrobacter, Acinetobacter and Janibacter exhibited notably high minimum inhibitory concentrations (MICs) for Sb(III) (>10 mM),making them the most highly Sb(III)-resistant bacteria to date. Thirty-six strains were able to oxidize Sb(III), including Pseudomonas-, Comamonas-, Acinetobacter-, Sphingopyxis-, Paracoccus- Aminobacter-, Arthrobacter-, Bacillus-, Janibacter- and Variovorax-like isolates. Canonical correspondence analysis (CCA) revealed that the soil concentrations of Sb and Cu were the most obvious environmental factors affecting the culturable bacterial population structures. Stepwise linear regression was used to create two predictive models for the correlation between soil characteristics and the bacterial Sb(III) or Cu(II) resistance. The concentrations of Sb and Cu in the soil was the significant factors affecting the bacterial Sb(III) resistance, whereas the concentrations of S and P in the soil greatly affected the bacterial Cu(II) resistance. The two stepwise linear regression models that we derived are as follows: MIC(Sb(III))=606.605+0.14533 x C(Sb)+0.4128 x C(Cu) and MIC((Cu)(II))=58.3844+0.02119 x C(S)+0.00199 x CP [where the MIC(Sb(III)) and MIC(Cu(II)) represent the average bacterial MIC for the metal of each soil (μM), and the C(Sb), C(Cu), C(S) and C(P) represent concentrations for Sb, Cu, S and P (mg/kg) in soil, respectively, p<0.01]. The stepwise linear regression models we developed suggest that metals as well as other soil physicochemical parameters can contribute to bacterial resistance to metals.

  2. Biomonitoring of antimony in environmental matrices from terrestrial and limnic ecosystems.

    PubMed

    Krachler, M; Burow, M; Emons, H

    1999-10-01

    Elder and poplar leaves from various sampling sites were studied with respect to their antimony content. Moreover, a retrospective determination of Sb was performed in representative limnic and terrestrial samples of the Federal Environmental Specimen Bank of Germany which have been collected over 14 years. The analytical procedure is based on an open vessel acid digestion of freeze-dried biological samples and the subsequent quantification of Sb in the digests by flow injection hydride generation atomic absorption spectrometry. Strict quality control schemes were applied to the entire procedure to guarantee accurate and precise results. No long-term changes of the Sb concentrations were found in spruce shoots or poplar leaves from different sampling sites. However, spruce shoots from a semi-natural region showed concentrations of Sb (approximately 22 ng g-1; range: 17-29 ng g-1) that were approximately four times lower than in corresponding samples from an urban-industrialized area. The analysis of virgin and washed elder leaves revealed that approximately 20-30% of the Sb is present on the leaf surface. Sb levels in elder leaves ranged from 5.2 +/- 0.3 ng g-1 in samples from Argentina to 589 +/- 30 ng g-1 in leaves collected directly beside a motorway in Germany. Similarly, poplar leaves from Argentina and Chile showed about 4 ng Sb g-1, whereas 150 ng Sb g-1 was found in poplar leaves from Germany. The lowest concentrations of Sb were determined in digests of pigeon eggs (approximately 2 ng g-1), bream liver (approximately 4 ng g-1) and deer liver (approximately 6 ng g-1). A similar pattern of Sb concentrations in spruce shoots, leaves or liver samples from an industrialized area and an agrarian ecosystem in Germany was established. Concentrations of Sb in elder leaves were closely associated with car traffic, giving maximum concentrations of 589 ng g-1 directly beside a motorway, 207 ng g-1 50 m from the motorway and 153 ng g-1 in a close residential area.

  3. Nozzle designs with pitch precursor ablatives

    NASA Technical Reports Server (NTRS)

    Blevins, H. R.; Bedard, R. J.

    1976-01-01

    Recent developments in carbon phenolic ablatives for solid rocket motor nozzles have yielded a pitch precursor carbon fiber offering significant raw material availability and cost saving advantages as compared to conventional rayon precursor material. This paper discusses the results of an experimental program conducted to assess the thermal performance and characterize the thermal properties of pitch precursor carbon phenolic ablatives. The end result of this program is the complete thermal characterization of pitch fabric, pitch mat, hybrid pitch/rayon fabric and pitch mat molding compound. With these properties determined an analytic capability now exists for predicting the thermal performance of these materials in rocket nozzle liner applications. Further planned efforts to verify material performance and analytical prediction procedures through actual rocket motor firings are also discussed.

  4. Sequestration and Transport of Lignin Monomeric Precursors

    SciTech Connect

    Liu, C.J.; Miao, Y.-C.; Zhang, K.-W.

    2011-01-18

    Lignin is the second most abundant terrestrial biopolymer after cellulose. It is essential for the viability of vascular plants. Lignin precursors, the monolignols, are synthesized within the cytosol of the cell. Thereafter, these monomeric precursors are exported into the cell wall, where they are polymerized and integrated into the wall matrix. Accordingly, transport of monolignols across cell membranes is a critical step affecting deposition of lignin in the secondarily thickened cell wall. While the biosynthesis of monolignols is relatively well understood, our knowledge of sequestration and transport of these monomers is sketchy. In this article, we review different hypotheses on monolignol transport and summarize the recent progresses toward the understanding of the molecular mechanisms underlying monolignol sequestration and transport across membranes. Deciphering molecular mechanisms for lignin precursor transport will support a better biotechnological solution to manipulate plant lignification for more efficient agricultural and industrial applications of cell wall biomass.

  5. Multivariate optimization of a method for antimony determination by hydride generation atomic fluorescence spectrometry in hair samples of patients undergoing chemotherapy against Leishmaniasis.

    PubMed

    Cardozo, Manuelle C; Cavalcante, Dannuza D; Silva, Daniel L F; Santos, Walter N L Dos; Bezerra, Marcos A

    2016-09-01

    A method was developed for determination of total antimony in hair samples from patients undergoing chemotherapy against Leishmaniasis based on the administration of pentavalent antimonial drugs. The method is based on microwave assisted digestion of the samples in a pressurized system, reduction of Sb5+ to Sb3+ with KI solution (10% w/v) in ascorbic acid (2%, w/v) and its subsequent determination by hydride generation atomic fluorescence spectrometry (HG-AFS). The proportions of each component (HCl, HNO3 and water) used in the digestion were studied applying a constrained mixtures design. The optimal proportions found were 50% water, 25% HNO3 and 25% HCl. Variables involved in the generation of antimony hydride were optimized using a Doehlert design revealing that good sensitivity is found when using 2.0% w/v NaBH4 and 4.4 mol L-1 HCl. Under the optimum experimental conditions, the method allows the determination of antimony in hair samples with detection and quantification limits of 1.4 and 4.6 ng g-1, respectively, and precision expressed as relative standard deviation (RSD) of 2.8% (n = 10 to 10.0 mg L-1). The developed method was applied in the analysis of hair samples from patients who take medication against Leishmaniasis.

  6. A visible light responsive rhodium and antimony-codoped SrTiO3 powdered photocatalyst loaded with an IrO2 cocatalyst for solar water splitting.

    PubMed

    Asai, Rikako; Nemoto, Hiroaki; Jia, Qingxin; Saito, Kenji; Iwase, Akihide; Kudo, Akihiko

    2014-03-07

    IrO2-loaded SrTiO3 doped with rhodium and antimony synthesized by a conventional solid-state reaction splits water under visible light and simulated sunlight irradiation giving 0.1% of the apparent quantum yield at 420 nm. The response wavelength up to 500 nm is the longest among achieved photocatalytic water splitting with one-step photoexcitation.

  7. Precursors prior to type IIn supernova explosions are common: Precursor rates, properties, and correlations

    SciTech Connect

    Ofek, Eran O.; Steinbok, Aviram; Arcavi, Iair; Gal-Yam, Avishay; Tal, David; Ben-Ami, Sagi; Yaron, Ofer; Sullivan, Mark; Shaviv, Nir J.; Kulkarni, Shrinivas R.; Nugent, Peter E.; Kasliwal, Mansi M.; Cenko, S. Bradley; Silverman, Jeffrey M.

    2014-07-10

    There is a growing number of Type IIn supernovae (SNe) which present an outburst prior to their presumably final explosion. These precursors may affect the SN display, and are likely related to poorly charted phenomena in the final stages of stellar evolution. By coadding Palomar Transient Factory (PTF) images taken prior to the explosion, here we present a search for precursors in a sample of 16 Type IIn SNe. We find five SNe IIn that likely have at least one possible precursor event (PTF 10bjb, SN 2010mc, PTF 10weh, SN 2011ht, and PTF 12cxj), three of which are reported here for the first time. For each SN we calculate the control time. We find that precursor events among SNe IIn are common: at the one-sided 99% confidence level, >50% of SNe IIn have at least one pre-explosion outburst that is brighter than 3 × 10{sup 7} L{sub ☉} taking place up to 1/3 yr prior to the SN explosion. The average rate of such precursor events during the year prior to the SN explosion is likely ≳ 1 yr{sup –1}, and fainter precursors are possibly even more common. Ignoring the two weakest precursors in our sample, the precursors rate we find is still on the order of one per year. We also find possible correlations between the integrated luminosity of the precursor and the SN total radiated energy, peak luminosity, and rise time. These correlations are expected if the precursors are mass-ejection events, and the early-time light curve of these SNe is powered by interaction of the SN shock and ejecta with optically thick circumstellar material.

  8. Monitoring of copper, arsenic and antimony levels in agricultural soils impacted and non-impacted by mining activities, from three regions in Chile.

    PubMed

    De Gregori, Ida; Fuentes, Edwar; Rojas, Mariela; Pinochet, Hugo; Potin-Gautier, Martine

    2003-04-01

    This paper reports a comparative study of the concentration of three important environmental elements that are often found together in mineral deposits and then associated with mining activities; copper, arsenic and antimony. These elements were determined in 26 different agricultural soils from regions I, II and V in Chile, zones where the most important and biggest copper industries of this country are located. As background levels of these elements in soils have not been well established, in this study, both, impacted and non-impacted agricultural soils from different regions were considered. The relationships between the concentrations of these elements in soils were also examined. The concentration ranges for copper, arsenic and antimony were 11-530; 2.7-202 and 0.42-11 mg kg(-1) respectively. The copper concentrations in non-polluted soils from the north and central zone of Chile were similar. However, three sites from the north region have copper concentration as higher as 100 mg kg(-1), values that exceed the critical concentration for copper in soils. The concentration of arsenic and antimony in the north soils were higher than in non-impacted ones and, in the case of arsenic, greatly exceeded the world average concentration reported for this element in soils. The highest arsenic and antimony concentrations were found in Calama and Quillagua soils, two different sites in the Loa valley. The arsenic/antimony concentration ratio was higher in Quillagua soil. The high concentrations of three elements determined in impacted soils from region V (Puchuncaví and Catemu valleys) clearly shows the impact produced in this zone by the industrial and mining activities developed in their proximities. At Puchuncaví valley a clear decrease was observed in copper, arsenic and antimony concentrations in soils on the function of the distance from the industrial complex "Las Ventanas", and all concentrations exceeded the reported critical values for this matrix. Instead at

  9. Polymeric precursors for fibers and matrices

    NASA Technical Reports Server (NTRS)

    Hurwitz, Frances I.

    1992-01-01

    Candidate polymeric precursors for ceramic fiber and matrix processing are discussed, with a view to the advantages and disadvantages of this approach relative to existing alternatives. The properties of ceramic products thus derived are noted to strongly depend on the molecular weight and structure of the starting polymer; in particular, the ceramic's composition and morphology are dependent on the character and extent of crosslinking, as well as on the path of pyrolysis. While large and complex structural ceramic components may ultimately be obtainable by these means, the polymer-precursor method is still in its developmental infancy.

  10. Nonlinear magnetohydrodynamics of edge localized mode precursors

    NASA Astrophysics Data System (ADS)

    Guo, Z. B.; Wang, Lu; Wang, X. G.

    2015-02-01

    A possible origin of edge-localized-mode (ELM) precursors based on nonlinear ideal peeling-ballooning mode is reported. Via nonlinear variational principle, a nonlinear evolution equation of the radial displacement is derived and solved, analytically. Besides an explosive growth in the initial nonlinear phase, it is found that the local displacement evolves into an oscillating state in the developed nonlinear phase. The nonlinear frequency of the ELM precursors scales as ωpr e˜x1 /3ξ̂ψ,i n 2 /3n , with x position in radial direction, ξ̂ ψ,i n strength of initial perturbation, and n toroidal mode number.

  11. Effect of hydroalcoholic extract of Echinacea purpurea in combination with meglumine antimoniate on treatment of Leishmania major-induced cutaneous leishmaniasis in BALB/c mice

    PubMed Central

    Sarkari, Bahador; Mohseni, Mobin; Moein, Mahmoud Reza; Shahriarirad, Reza; Asgari, Qasem

    2017-01-01

    Context: Progressive resistance of Leishmania parasite to available drugs including, meglumine antimoniate, has been reported from various regions of the world, especially Iran. Aims: This study was conducted to evaluate the effect of hydroalcoholic extract of Echinacea purpurea in a combination therapy with glucantime in the treatment of cutaneous leishmaniasis caused by Leishmania major. Materials and Methods: Hydroalcoholic extract of E. purpurea was prepared from the plant. Amastigote form of L. major was inoculated to the tail base of thirty mice. After their tails became wounded, mice were divided into six groups. The first group was used as control and the second group received 100 mg/kg of Echinacea extract (orally). The third group was treated by meglumine antimoniate with dose of 20 mg/kg. Combination therapy was used for group four, five, and six where the mice received a different concentration of extract (100–200 mg/kg) and glucantime (10–20 mg/kg). The size of the cutaneous lesion on tail base was measured regularly. Findings were analyzed by SPSS software and using Kruskal-Wallis test. Results: The sizes of the lesion were increased in all mice of control group by the time. The mean size of lesions in mice receiving the extract and/or receiving the extract along with meglumine antimoniate was lower than those of control mice, but the differences were not statistically significant (P > 0.05). On the other hand, the differences between the group of mice which received meglumine antimoniate alone, and the rest of groups were statistically significant (P < 0.05). Conclusion: E. purpurea extract in doses which have been used in this study and combination with meglumine antimoniate was not much effective against L. major in BALB/C mice. PMID:28251109

  12. Biochemical Removal of HAP Precursors from Coal

    SciTech Connect

    Olson, Gregory J

    1997-05-12

    Column biooxidation tests with Kentucky coal confirmed results of earlier shake flask tests showing significant removal from the coal of arsenic, selenium, cobalt, manganese, nickel and cadmium. Rates of pyrite biooxidation in Kentucky coal were only slightly more than half the rates found previously for Indiana and Pittsburgh coals. Removal of pyrite from Pittsburgh coal by ferric ion oxidation slows markedly as ferrous ions accumulate in solution, requiring maintenance of high redox potentials in processes designed for removal of pyrite and hazardous air pollutant (HAP) precursors by circulation of ferric solutions through coal. The pyrite oxidation rates obtained in these tests were used by Unifield Engineering to support the conceptual designs for alternative pyrite and HAP precursor bioleaching processes for the phase 2 pilot plant. Thermophilic microorganisms were tested to determine if mercury could be mobilized from coal under elevated growth temperatures. There was no evidence for mercury removal from coal under these conditions. However, the activity of the organisms may have liberated mercury physically. It is also possible that the organisms dissolved mercury and it readsorbed to the clay preferentially. Both of these possibilities are undergoing further testing. The Idaho National Engineering and Environmental Laboratory's (INEEL) slurry column reactor was operated and several batches of feed coal, product coal, waste solids and leach solutions were submitted to LBL for HAP precursor analysis. Results to date indicate significant removal of mercury, arsenic and other HAP precursors in the combined physical-biological process.

  13. Janus microgels produced from functional precursor polymers.

    PubMed

    Seiffert, Sebastian; Romanowsky, Mark B; Weitz, David A

    2010-09-21

    Micrometer-sized Janus particles of many kinds can be formed using droplet microfluidics, but in existing methods, the microfluidic templating is strongly coupled to the material synthesis, since droplet solidification occurs through rapid polymerization right after droplet formation. This circumstance limits independent control of the material properties and the morphology of the resultant particles. In this paper, we demonstrate a microfluidic technique to produce functional Janus microgels from prefabricated, cross-linkable precursor polymers. This approach separates the polymer synthesis from the particle gelation, thus allowing the microfluidic droplet templating and the functionalization of the matrix polymer to be performed and controlled in two independent steps. We use microfluidic devices to emulsify semidilute solutions of cross-linkable, chemically modified or unmodified poly(N-isopropylacrylamide) precursors and solidify the drops via polymer-analogous gelation. The resultant microgel particles exhibit two distinguishable halves which contain most of the modified precursors, and the unmodified matrix polymer separates these materials. The spatial distribution of the modified precursors across the particles can be controlled by the flow rates during the microfluidic experiments. We also form hollow microcapsules with two different sides (Janus shells) using double emulsion droplets as templates, and we produce Janus microgels that are loaded with a ferromagnetic additive which allows remote actuation of the microgels.

  14. Profiling Identifies Precursor Suspects: Notch Family Again!

    PubMed Central

    Breunig, Joshua J.; Rakic, Pasko

    2011-01-01

    Newborn neurons in the adult dentate gyrus pass through several distinct precursor and progenitor classes prior to differentiation. In this issue of Cell Stem Cell, Lugert et al. (2010) characterized their strikingly different proliferative behaviors after neurogenic stimuli or aging. PMID:20452310

  15. Superconductor precursor mixtures made by precipitation method

    DOEpatents

    Bunker, Bruce C.; Lamppa, Diana L.; Voigt, James A.

    1989-01-01

    Method and apparatus for preparing highly pure homogeneous precursor powder mixtures for metal oxide superconductive ceramics. The mixes are prepared by instantaneous precipitation from stoichiometric solutions of metal salts such as nitrates at controlled pH's within the 9 to 12 range, by addition of solutions of non-complexing pyrolyzable cations, such as alkyammonium and carbonate ions.

  16. Sol-gel precursors and products thereof

    DOEpatents

    Warren, Scott C.; DiSalvo, Jr., Francis J.; Weisner, Ulrich B.

    2017-02-14

    The present invention provides a generalizable single-source sol-gel precursor capable of introducing a wide range of functionalities to metal oxides such as silica. The sol-gel precursor facilitates a one-molecule, one-step approach to the synthesis of metal-silica hybrids with combinations of biological, catalytic, magnetic, and optical functionalities. The single-source precursor also provides a flexible route for simultaneously incorporating functional species of many different types. The ligands employed for functionalizing the metal oxides are derived from a library of amino acids, hydroxy acids, or peptides and a silicon alkoxide, allowing many biological functionalities to be built into silica hybrids. The ligands can coordinate with a wide range of metals via a carboxylic acid, thereby allowing direct incorporation of inorganic functionalities from across the periodic table. Using the single-source precursor a wide range of functionalized nanostructures such as monolith structures, mesostructures, multiple metal gradient mesostructures and Stober-type nanoparticles can be synthesized. ##STR00001##

  17. Detection of Chemical Precursors of Explosives

    NASA Technical Reports Server (NTRS)

    Li, Jing

    2012-01-01

    Certain selected chemicals associated with terrorist activities are too unstable to be prepared in final form. These chemicals are often prepared as precursor components, to be combined at a time immediately preceding the detonation. One example is a liquid explosive, which usually requires an oxidizer, an energy source, and a chemical or physical mechanism to combine the other components. Detection of the oxidizer (e.g. H2O2) or the energy source (e.g., nitromethane) is often possible, but must be performed in a short time interval (e.g., 5 15 seconds) and in an environment with a very small concentration (e.g.,1 100 ppm), because the target chemical(s) is carried in a sealed container. These needs are met by this invention, which provides a system and associated method for detecting one or more chemical precursors (components) of a multi-component explosive compound. Different carbon nanotubes (CNTs) are loaded (by doping, impregnation, coating, or other functionalization process) for detecting of different chemical substances that are the chemical precursors, respectively, if these precursors are present in a gas to which the CNTs are exposed. After exposure to the gas, a measured electrical parameter (e.g. voltage or current that correlate to impedance, conductivity, capacitance, inductance, etc.) changes with time and concentration in a predictable manner if a selected chemical precursor is present, and will approach an asymptotic value promptly after exposure to the precursor. The measured voltage or current are compared with one or more sequences of their reference values for one or more known target precursor molecules, and a most probable concentration value is estimated for each one, two, or more target molecules. An error value is computed, based on differences of voltage or current for the measured and reference values, using the most probable concentration values. Where the error value is less than a threshold, the system concludes that the target

  18. Treatment of disinfection by-product precursors.

    PubMed

    Bond, T; Goslan, E H; Parsons, S A; Jefferson, B

    2011-01-01

    Formation of harmful disinfection by-products (DBPs), of which trihalomethanes (THMs) and haloacetic acids (HAAs) are the major groups, can be controlled by removal of natural organic matter (NOM) before disinfection. In the literature, removal of precursors is variable, even with the same treatment. The treatment of DBP precursors and NOM was examined with the intention of outlining precursor removal strategies for various water types. Freundlich adsorption parameters and hydroxyl rate constants were collated from the literature to link treatability by activated carbon and advanced oxidation processes (AOPs), respectively, to physico-chemical properties. Whereas hydroxyl rate constants did not correlate meaningfully with any property, a moderate correlation was found between Freundlich parameters and log K(ow), indicating activated carbon will preferentially adsorb hydrophobic NOM. Humic components of NOM are effectively removed by coagulation, and, where they are the principal precursor source, coagulation may be sufficient to control DBPs. Where humic species remaining post-coagulation retain significant DBP formation potential (DBPFP), activated carbon is deemed a suitable process selection. Anion exchange is an effective treatment for transphilic species, known for high carboxylic acid functionality, and consequently is recommended for carboxylic acid precursors. Amino acids have been linked to HAA formation and are important constituents of algal organic matter. Amino acids are predicted to be effectively removed by biotreatment and nanofiltration. Carbohydrates have been found to reach 50% of NOM in river waters. If the carbohydrates were to pose a barrier to successful DBP control, additional treatment stages such as nanofiltration are likely to be required to reduce their occurrence.

  19. Boron nitride fibers from polymer precursors

    SciTech Connect

    Wade, B.E.

    1992-12-31

    Conversion of polymer precursors to high performance boron nitride fibers as explored through a fundamental study of the mutually dependent chemical, morphological, and processing requirements in precursor polymer synthesis, formation of continuous precursor fibers, and finally thermochemical conversion to oriented boron nitride fibers. Polyborate and polyborazylene precursors were investigated. method of incorporating polyborazine in polyborate were also explored in order to stabilize the shape of polyborate fibers and to help initiate an orientable boron nitride structure. Polyborazylene, a polyborazine of fused borazine polycyclic structures was chosen for study as a precursor for boron nitride fibers because of the closeness of its structure to that of the desired turbostratic boron nitride. Both poly(ethylene oxide) and poly(methyl methacrylate) were found to be compatible with the monomer, borazine, and polyborazylenesolutions with monoglyme. They could be used to build the viscosity of solutions. However, fibers that were hand-drawn from these solutions were very sticky and quickly hydrolyzed in room atmosphere. Conversion of polyborazylene to oriented boron nitride fibers was not realized. Processable polyborates were produced by polycondensation of trimethoxyboroxine and boric acid and also by disproportionation or trimethyoxyboraxine. It was shown that the rheological characteristics of the polyborate formed could be controlled by an appropriate combination of the conversion of the monomer to polymer and the addition of a linear organic polymer as a rheological aid. Poly(methyl methacrylate) was found to be a suitable rheological aid, with a decomposition temperature that is high enough to facilitate its incorporation in the polymerizing system and low energy to be fugitive during thermochemical conversion of the polyborate to boron nitride.

  20. Source Identification Of Airborne Antimony On The Basis Of The Field Monitoring And The Source Profiling

    NASA Astrophysics Data System (ADS)

    Iijima, A.; Sato, K.; Fujitani, Y.; Fujimori, E.; Tanabe, K.; Ohara, T.; Shimoda, M.; Kozawa, K.; Furuta, N.

    2008-12-01

    The results of the long-term monitoring of airborne particulate matter (APM) in Tokyo indicated that APM have been extremely enriched with antimony (Sb) compared to crustal composition. This observation suggests that the airborne Sb is distinctly derived from human activities. According to the material flow analysis, automotive brake abrasion dust and fly ash from waste incinerator were suspected as the significant Sb sources. To clarify the emission sources of the airborne Sb, elemental composition, particle size distribution, and morphological profiles of dust particles collected from two possible emission sources were characterized and compared to the field observation data. Brake abrasion dust samples were generated by using a brake dynamometer. During the abrasion test, particle size distribution was measured by an aerodynamic particle sizer spectrometer. Concurrently, size- classified dust particles were collected by an Andersen type air sampler. Fly ash samples were collected from several municipal waste incinerators, and the bulk ash samples were re-dispersed into an enclosed chamber. The measurement of particle size distribution and the collection of size-classified ash particles were conducted by the same methodologies as described previously. Field observations of APM were performed at a roadside site and a residential site by using an Andersen type air sampler. Chemical analyses of metallic elements were performed by an inductively coupled plasma atomic emission spectrometry and an inductively coupled plasma mass spectrometr. Morphological profiling of the individual particle was conducted by a scanning electron microscope equipped with an energy dispersive X-ray spectrometer. High concentration of Sb was detected from both of two possible sources. Particularly, Sb concentrations in a brake abrasion dust were extremely high compared to that in an ambient APM, suggesting that airborne Sb observed at the roadside might have been largely derived from