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Sample records for cyclo-oxygenase-inhibitor sulindac sulfide

  1. Genotoxicity of the cyclo-oxygenase-inhibitor sulindac sulfide in the filamentous fungus Aspergillus nidulans Genotoxicidade de sulfeto de sulindaco em Aspergillus nidulans

    OpenAIRE

    Claudinéia Conationi da Silva Franco; Claudia Tiemi Miyamoto; Juliane Rocha de Sant'Anna; Marialba Avezum Alves Castro-Prado

    2007-01-01

    Sulindac sulfide is a non-steroidal anti-inflammatory drug (NSAID) with chemopreventive effect on human cancer cells. Due to the involvement of the somatic recombination in the carcinogenic process, sulindac sulfide's recombinogenic potential was evaluated by the Homozygotization Index (HI) in the filamentous fungus Aspergillus nidulans. The drug's recombinogenic potential was evaluated by its capacity to induce homozygosis of recessive genes from heterozygous diploid cells. Sulindac sulfide ...

  2. Genotoxicity of the cyclo-oxygenase-inhibitor sulindac sulfide in the filamentous fungus Aspergillus nidulans Genotoxicidade de sulfeto de sulindaco em Aspergillus nidulans

    Directory of Open Access Journals (Sweden)

    Claudinéia Conationi da Silva Franco

    2007-09-01

    Full Text Available Sulindac sulfide is a non-steroidal anti-inflammatory drug (NSAID with chemopreventive effect on human cancer cells. Due to the involvement of the somatic recombination in the carcinogenic process, sulindac sulfide's recombinogenic potential was evaluated by the Homozygotization Index (HI in the filamentous fungus Aspergillus nidulans. The drug's recombinogenic potential was evaluated by its capacity to induce homozygosis of recessive genes from heterozygous diploid cells. Sulindac sulfide at 175 and 350 µM concentrations induced mitotic recombination in A. nidulans diploid cells, with HI values for genetic markers higher than 2.0, and significantly different from control HI values. The recombinogenic effect of NSAID was related to the induction of DNA strand breaks and cell cycle alterations. Sulindac sulfide's carcinogenic potential was also discussed.Sulfeto de sulindaco é um antiinflamatório não-esteroidal com efeitos quimiopreventivos em cânceres humanos. O presente estudo teve como objetivo avaliar o potencial recombinagênico do sulfeto de sulindaco em células diplóides de Aspergillus nidulans. O efeito recombinagênico da droga foi demonstrado através da homozigotização de genes recessivos, previamente presentes em heterozigose. Os valores de HI (Índice de Homozigotização para diferentes marcadores genéticos apresentaram-se maiores do que 2,0 e significativamente diferentes dos valores obtidos em sulfeto de sulindaco ausência da droga (controle. O potencial recombinagênico do sulfeto de sulindaco foi associado à indução de quebras na molécula do DNA e a alterações no ciclo celular. O potencial carcinogênico do sulfeto de sulindaco foi discutido no presente trabalho.

  3. Sulindac Sulfide, but Not Sulindac Sulfone, Inhibits Colorectal Cancer Growth

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    Christopher S. Williams

    1999-06-01

    Full Text Available Sulindac sulfide, a metabolite of the nonsteroidal antiinflammatory drug (NSAID sulindac sulfoxide, is effective at reducing tumor burden in both familial adenomatous polyposis patients and in animals with colorectal cancer. Another sulindac sulfoxide metabolite, sulindac sulfone, has been reported to have antitumor properties without inhibiting cyclooxygenase activity. Here we report the effect of sulindac sulfone treatment on the growth of colorectal carcinoma cells. We observed that sulindac sulfide or sulfone treatment of HCA-7 cells led to inhibition of prostaglandin E2 production. Both sulindac sulfide and sulfone inhibited HCA-7 and HCT-116 cell growth in vitro. Sulindac sulfone had no effect on the growth of either HCA-7 or HCT-116 xenografts, whereas the sulfide derivative inhibited HCA-7 growth in vivo. Both sulindac sulfide and sulfone inhibited colon carcinoma cell growth and prostaglandin production in vitro, but sulindac sulfone had no effect on the growth of colon cancer cell xenografts in nude mice.

  4. The influence of cyclo-oxygenase inhibitors on the cardiovascular effects of hydralazine in rats.

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    Vidrio, H; Garcia-Marquez, F

    1985-01-01

    In order to explore the postulated role of prostaglandins in the vasodilator effects of hydralazine, blood pressure and heart rate responses to the drug were determined in anesthetized and conscious rats with and without pretreatment with indomethacin or aspirin. Changes in rectal temperature were also measured. In control animals, hydralazine produced an almost immediate fall in blood pressure and a slowly developing tachycardia which bore no temporal relation with the hypotension. These effects were accompanied by a moderate increase in temperature. Pretreatment with the cyclo-oxygenase inhibitors did not reduce the blood pressure response, but completely blocked and in some cases reversed the tachycardia. The hyperthermic response was also reversed. These results can be taken as evidence for a role of prostaglandins in the tachycardia and hyperthermia, but not in the hypotension elicited by hydralazine in rats. In the absence of direct measurements of prostaglandin synthesis and release, however, no firm support for this possibility is offered by the present findings and alternative explanations are considered.

  5. Sulindac Sulfide Differentially Induces Apoptosis in Smac-Proficient and -Deficient Human Colon Cancer Cells

    OpenAIRE

    Shi, Jingxue; He, Qin; An, Jie; Sun, Hong; Huang, Ying; Sheikh, M. Saeed

    2009-01-01

    Sulindac, the non-steroidal anti-inflammatory drug has shown promise in the prevention of colon cancer but the molecular mechanisms by which it mediates such effects remain to be elucidated. Sulindac sulfide is the major active metabolite of sulindac and believed to be responsible for mediating the effects of sulindac. Previously, our group and others have shown that sulindac sulfide induces apoptosis by engaging death receptor and mitochondrial pathways and that a cross-talk exists between t...

  6. Sulindac and its metabolites: sulindac sulfide and sulindac sulfone enhance cytotoxic effects of arsenic trioxide on leukemic cell lines.

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    Stępnik, Maciej; Ferlińska, Magdalena; Smok-Pieniążek, Anna; Gradecka-Meesters, Dobrosława; Arkusz, Joanna; Stańczyk, Małgorzata

    2011-08-01

    The effects of arsenic trioxide (ATO) in combination with sulindac (SUL), sulindac sulfide (SS) or sulindac sulfone (SF) on human (Jurkat, HL-60, K562 and HPB-ALL) and mouse (EL-4) leukemic cell lines were investigated. The cells showed different sensitivity to sulindacs (2.5-200 μM) with SS being the most cytotoxic (72 h WST-1 reduction test). The cytotoxicity of ATO was enhanced by combination with sulindacs. The combination of ATO (1 μM) with SS or SF at concentrations over 50 μM induced considerable cytotoxicity in all cell lines. Normal human lymphocytes exposed for 48 h to the combinations showed smaller decrease in viability. Measurements of Jurkat, HL-60 and K562 cells exposed to ATO (1 μM) and sulindacs (100 μM or 200 μM for K562 cells) indicated apoptosis as the main cell death mechanism. The mitochondrial membrane potential measurements (JC-1 probe) indicated an active involvement of mitochondria in the process. The results did not indicate involvement of an inhibitory effect of the combinations on NF-κB activity in Jurkat, HL-60 and K562 cells.

  7. Sulindac sulfide suppresses 5-lipoxygenase at clinically relevant concentrations.

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    Steinbrink, Svenja D; Pergola, Carlo; Bühring, Ulrike; George, Sven; Metzner, Julia; Fischer, Astrid S; Häfner, Ann-Kathrin; Wisniewska, Joanna M; Geisslinger, Gerd; Werz, Oliver; Steinhilber, Dieter; Maier, Thorsten J

    2010-03-01

    Sulindac is a non-selective inhibitor of cyclooxygenases (COX) used to treat inflammation and pain. Additionally, non-COX targets may account for the drug's chemo-preventive efficacy against colorectal cancer and reduced gastrointestinal toxicity. Here, we demonstrate that the pharmacologically active metabolite of sulindac, sulindac sulfide (SSi), targets 5-lipoxygenase (5-LO), the key enzyme in the biosynthesis of proinflammatory leukotrienes (LTs). SSi inhibited 5-LO in ionophore A23187- and LPS/fMLP-stimulated human polymorphonuclear leukocytes (IC(50) approximately 8-10 microM). Importantly, SSi efficiently suppressed 5-LO in human whole blood at clinically relevant plasma levels (IC(50) = 18.7 microM). SSi was 5-LO-selective as no inhibition of related lipoxygenases (12-LO, 15-LO) was observed. The sulindac prodrug and the other metabolite, sulindac sulfone (SSo), failed to inhibit 5-LO. Mechanistic analysis demonstrated that SSi directly suppresses 5-LO with an IC(50) of 20 muM. Together, these findings may provide a novel molecular basis to explain the COX-independent pharmacological effects of sulindac under therapy.

  8. Sulindac sulfide inhibits colon cancer cell growth and downregulates specificity protein transcription factors

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    Li, Xi; Pathi, Satya S.; Safe, Stephen

    2015-01-01

    Background Specificity protein (Sp) transcription factors play pivotal roles in maintaining the phenotypes of many cancers. We hypothesized that the antineoplastic effects of sulindac and its metabolites were due, in part, to targeting downregulation of Sp transcription factors. Methods The functional effects of sulindac, sulindac sulfone and sulindac sulfide on colon cancer cell proliferation were determined by cell counting. Effects of these compounds on expression of Sp1, Sp3, Sp4 and pro-...

  9. Myeloid zinc finger 1 mediates sulindac sulfide-induced upregulation of death receptor 5 of human colon cancer cells.

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    Horinaka, Mano; Yoshida, Tatsushi; Tomosugi, Mitsuhiro; Yasuda, Shusuke; Sowa, Yoshihiro; Sakai, Toshiyuki

    2014-08-08

    A combined therapy of sulindac sulfide and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising strategy for the treatment of cancer. Sulindac sulfide had been shown to induce the expression of death receptor 5 (DR5), a receptor for TRAIL, and sensitize cancer cells to TRAIL-induced apoptosis; however, the molecular mechanism underlying the upregulation of DR5 has not yet been elucidated. We demonstrate here that myeloid zinc finger 1 (MZF1) mediates the induction of DR5 by sulindac sulfide. Sulindac sulfide induced the expression of DR5 at the protein and mRNA levels in colon cancer SW480 cells. Furthermore, sulindac sulfide increased DR5 promoter activity. We showed that sulindac sulfide stimulated DR5 promoter activity via the -301 to -253 region. This region contained a putative MZF1-binding site. Site-directed mutations in the site abrogated the enhancement in DR5 promoter activity by sulindac sulfide. MZF1 directly bound to the putative MZF1-binding site of the DR5 promoter and the binding was increased by sulindac sulfide. The expression of MZF1 was also increased by sulindac sulfide, and MZF1 siRNA attenuated the upregulation of DR5 by sulindac sulfide. These results indicate that sulindac sulfide induces the expression of DR5 by up-regulating MZF1.

  10. Docosahexaenoic acid sensitizes colon cancer cells to sulindac sulfide-induced apoptosis.

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    Lim, Soo-Jeong; Lee, Eunmyong; Lee, Eun-Hye; Kim, Soo-Yeon; Cha, Jun Hyung; Choi, Hwanho; Park, Wanseo; Choi, Hyeon Kyeom; Ko, Seong-Hee; Kim, So Hee

    2012-06-01

    Sulindac analogs represent one of the most efficacious groups of NSAIDs reducing the risk of colon cancer. Recent studies have shown that sulindac sulfide, a sulindac analog effective at lower doses compared to its parent compound, triggers the death receptor (DR)5-dependent extrinsic apoptotic pathway. Induction of apoptosis via activation of the DR-mediated pathway would be an ideal therapeutic strategy to eliminate cancer cells. In this study, we investigated the possibility that colon cancer cells are sensitized to sulindac sulfide-induced apoptosis by docosahexaenoic acid (DHA), via activation of the DR/extrinsic apoptotic pathway. Our data demonstrated that DHA combination sensitized colon cancer cells to sulindac sulfide-induced apoptosis, leading to enhanced growth suppression of human colon cancer xenografts. The combination effect was primarily attributed to increased cleavage of poly(ADP-ribose) polymerase (PARP) and caspase-8 activation. Moreover, pretreatment with z-IETD-FMK (caspase-8 inhibitor) or stable expression of dominant negative caspase-8 genes blocked DHA/sulindac sulfide cotreatment-induced apoptosis. In view of the finding that DR5 silencing abrogated the combination-stimulated apoptosis, we propose that apoptotic synergy induced by sulindac sulfide plus DHA is mediated via DR5. Our findings collectively support the utility of a combination of sulindac sulfide and DHA in the effective prevention and treatment of colon cancer.

  11. Effect of sulindac sulfide on metallohydrolases in the human colon cancer cell line HT-29.

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    Guillen-Ahlers, Hector; Tan, Jiangning; Castellino, Francis J; Ploplis, Victoria A

    2011-01-01

    Matrix metalloproteinase 7 (MMP7), a metallohydrolase involved in the development of several cancers, is downregulated in the Apc(Min/+) colon cancer mouse model following sulindac treatment. To determine whether this effect is relevant to the human condition, HT-29 human colon cancer cells were treated with sulindac and its metabolites, and compared to results obtained from in vivo mouse studies. The expression of MMP7 was monitored. The results demonstrated that sulindac sulfide effectively downregulated both MMP7 expression and activity. Furthermore, activity-based proteomics demonstrated that sulindac sulfide dramatically decreased the activity of leukotriene A4 hydrolase in HT-29 cells as reflected by a decrease in the level of its product, leukotriene B4. This study demonstrates that the effect of sulindac treatment in a mouse model of colon cancer may be relevant to the human counterpart and highlights the effect of sulindac treatment on metallohydrolases.

  12. Effect of sulindac sulfide on metallohydrolases in the human colon cancer cell line HT-29.

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    Hector Guillen-Ahlers

    Full Text Available Matrix metalloproteinase 7 (MMP7, a metallohydrolase involved in the development of several cancers, is downregulated in the Apc(Min/+ colon cancer mouse model following sulindac treatment. To determine whether this effect is relevant to the human condition, HT-29 human colon cancer cells were treated with sulindac and its metabolites, and compared to results obtained from in vivo mouse studies. The expression of MMP7 was monitored. The results demonstrated that sulindac sulfide effectively downregulated both MMP7 expression and activity. Furthermore, activity-based proteomics demonstrated that sulindac sulfide dramatically decreased the activity of leukotriene A4 hydrolase in HT-29 cells as reflected by a decrease in the level of its product, leukotriene B4. This study demonstrates that the effect of sulindac treatment in a mouse model of colon cancer may be relevant to the human counterpart and highlights the effect of sulindac treatment on metallohydrolases.

  13. Nutrient Availability Alters the Effect of Autophagy on Sulindac Sulfide-Induced Colon Cancer Cell Apoptosis

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    Shiun-Kwei Chiou

    2012-01-01

    Full Text Available Autophagy is a catabolic process by which a cell degrades its intracellular materials to replenish itself. Induction of autophagy under various cellular stress stimuli can lead to either cell survival or cell death via apoptotic and/or autophagic (nonapoptotic pathways. The NSAID sulindac sulfide induces apoptosis in colon cancer cells. Here, we show that inhibition of autophagy under serum-deprived conditions resulted in significant reductions of sulindac sulfide-induced apoptosis in HT-29 colon cancer cells. In contrast, inhibition of autophagy under conditions where serum is available significantly increased sulindac sulfide-induced apoptosis in HT-29 cells. We previously showed that the apoptosis inhibitor, survivin, plays a role in regulating NSAID-induced apoptosis and autophagic cell death. Here, we show that survivin protein half-life is increased in the presence of autophagy inhibitors under serum-deprived conditions, but not under conditions when serum is available. Thus, the increased levels of survivin may be a factor contributing to inhibition of sulindac sulfide-induced apoptosis under serum-deprived conditions. These results suggest that whether a cell lives or dies due to autophagy induction depends on the balance of factors that regulate both autophagic and apoptotic processes.

  14. Myeloid zinc finger 1 mediates sulindac sulfide-induced upregulation of death receptor 5 of human colon cancer cells

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    Mano Horinaka; Tatsushi Yoshida; Mitsuhiro Tomosugi; Shusuke Yasuda; Yoshihiro Sowa; Toshiyuki Sakai

    2014-01-01

    A combined therapy of sulindac sulfide and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising strategy for the treatment of cancer. Sulindac sulfide had been shown to induce the expression of death receptor 5 (DR5), a receptor for TRAIL, and sensitize cancer cells to TRAIL-induced apoptosis; however, the molecular mechanism underlying the upregulation of DR5 has not yet been elucidated. We demonstrate here that myeloid zinc finger 1 (MZF1) mediates the induction of...

  15. Effects of single-nucleotide polymorphisms of FMO3 and FMO6 genes on pharmacokinetic characteristics of sulindac sulfide in premature labor.

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    Park, Sunny; Lee, Na Ra; Lee, Kyung Eun; Park, Jin Young; Kim, Young Ju; Gwak, Hye Sun

    2014-01-01

    This study aimed to investigate the effects of polymorphisms of the flavin-containing mono-oxygenase 3 (FMO3) and flavin-containing mono-oxygenase 6 (FMO6) genes on the pharmacokinetics of sulindac sulfide, the active metabolite of sulindac, in patients with preterm labor. Ten single-nucleotide polymorphisms (SNPs) were genotyped, and plasma sulindac sulfide concentrations were measured at 0, 1.5, 4, and 10 hours after drug administration. The area under the curve from time 0 to the last sampling time point (AUC(last)) for sulindac sulfide was obtained. The AUC(last) of sulindac sulfide was significantly higher in patients with variant-type homozygotes of FMO3 (rs909530) than those with ancestral alleles or heterozygotes. FMO3 (rs2266780) was in complete linkage disequilibrium with FMO6 (rs7885012), and there was marginal significance between the genotypes (P = 0.049). From multiple linear regression models, FMO3 (rs909530) was found to have significant influence on the AUClast of sulindac sulfide after adjusting for gestational age, weight, and all studied SNPs. The predictive contribution of rs909530 to the variability of sulindac sulfide AUC(last) was 27.0%. In conclusion, the results of this study could help clinicians predict the efficacies and side effects of sulindac in the development of individualized treatment of patients with preterm labor.

  16. Sulindac sulfide induces autophagic death in gastric epithelial cells via survivin down-regulation: a mechanism of NSAIDs-induced gastric injury.

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    Chiou, Shiun-Kwei; Hoa, Neil; Hodges, Amy

    2011-06-01

    Sulindac sulfide, a nonsteroidal anti-inflammatory drug (NSAID), has anti-tumorigenic and anti-inflammatory activities, but causes gastric mucosal damage. NSAIDs cause gastric injury in part by down-regulation of Survivin, an apoptosis inhibitor, resulting in apoptosis induction. Autophagy is a process that promotes cellular health by destroying unwanted cellular materials. Excessive autophagy induction could lead to a non-apoptotic cell death (autophagic cell death). The present study showed that sulindac sulfide at a physiological concentration also induces autophagic death in human gastric epithelial AGS and rat gastric epithelial RGM-1 cells, and that Survivin down-regulation is a mechanism involved: Sulindac sulfide treatment increased LC3b-II and APG7 levels and cytosolic vacuole formation, indications of autophagy induction, in AGS and RGM-1 cells. Sulindac sulfide treatment induced AGS and RGM-1 cell death, which was significantly reduced by pretreatment with the autophagy inhibitors 3-methyladenine and chloroquine, indicating that sulindac sulfide induced autophagic cell death. Stable overexpression of Survivin in RGM-1 cells did not inhibit the induction of LC3b-II levels or vacuole formation by sulindac sulfide, but significantly reduced the resulting cell death, suggesting that Survivin may inhibit autophagic cell death downstream of LC3b-II induction and vacuole formation. Indeed, siRNA depletion of LC3b in AGS cells inhibited the down-regulation of Survivin levels and the induction of cell death by sulindac sulfide, confirming that down-regulation of Survivin occurs in the autophagy pathway downstream of LC3b-II induction by sulindac sulfide. Induction of Survivin-dependent autophagic cell death is a novel mechanism by which sulindac sulfide induces gastric mucosal injury.

  17. Sulindac Sulfide Induces the Formation of Large Oligomeric Aggregates of the Alzheimer's Disease Amyloid-β Peptide Which Exhibit Reduced Neurotoxicity.

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    Prade, Elke; Barucker, Christian; Sarkar, Riddhiman; Althoff-Ospelt, Gerhard; Lopez del Amo, Juan Miguel; Hossain, Shireen; Zhong, Yifei; Multhaup, Gerd; Reif, Bernd

    2016-03-29

    Alzheimer's disease is characterized by deposition of the amyloid β-peptide (Aβ) in brain tissue of affected individuals. In recent years, many potential lead structures have been suggested that can potentially be used for diagnosis and therapy. However, the mode of action of these compounds is so far not understood. Among these small molecules, the nonsteroidal anti-inflammatory drug (NSAID) sulindac sulfide received a lot of attention. In this manuscript, we characterize the interaction between the monomeric Aβ peptide and the NSAID sulindac sulfide. We find that sulindac sulfide efficiently depletes the pool of toxic oligomers by enhancing the rate of fibril formation. In vitro, sulindac sulfide forms colloidal particles which catalyze the formation of fibrils. Aggregation is immediate, presumably by perturbing the supersaturated Aβ solution. We find that sulindac sulfide induced Aβ aggregates are structurally homogeneous. The C-terminal part of the peptide adopts a β-sheet structure, whereas the N-terminus is disordered. The salt bridge between D23 and K28 is present, similar as in wild type fibril structures. (13)C-(19)F transferred echo double resonance experiments suggest that sulindac sulfide colocalizes with the Aβ peptide in the aggregate.

  18. NOSH-sulindac (AVT-18A) is a novel nitric oxide- and hydrogen sulfide-releasing hybrid that is gastrointestinal safe and has potent anti-inflammatory, analgesic, antipyretic, anti-platelet, and anti-cancer properties

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    Kashfi, Khosrow; Chattopadhyay, Mitali; Kodela, Ravinder

    2015-01-01

    Sulindac is chemopreventive and has utility in patients with familial adenomatous polyposis; however, side effects preclude its long-term use. NOSH-sulindac (AVT-18A) releases nitric oxide and hydrogen sulfide, was designed to be a safer alternative. Here we compare the gastrointestinal safety, anti-inflammatory, analgesic, anti-pyretic, anti-platelet, and anti-cancer properties of sulindac and NOSH-sulindac administered orally to rats at equimolar doses. Gastrointestinal safety: 6 h post-adm...

  19. Cyclooxygenase-1-selective inhibitors based on the (E)-2'-des-methyl-sulindac sulfide scaffold.

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    Liedtke, Andy J; Crews, Brenda C; Daniel, Cristina M; Blobaum, Anna L; Kingsley, Philip J; Ghebreselasie, Kebreab; Marnett, Lawrence J

    2012-03-08

    Prostaglandins (PGs) are powerful lipid mediators in many physiological and pathophysiological responses. They are produced by oxidation of arachidonic acid (AA) by cyclooxygenases (COX-1 and COX-2) followed by metabolism of endoperoxide intermediates by terminal PG synthases. PG biosynthesis is inhibited by nonsteroidal anti-inflammatory drugs (NSAIDs). Specific inhibition of COX-2 has been extensively investigated, but relatively few COX-1-selective inhibitors have been described. Recent reports of a possible contribution of COX-1 in analgesia, neuroinflammation, or carcinogenesis suggest that COX-1 is a potential therapeutic target. We designed, synthesized, and evaluated a series of (E)-2'-des-methyl-sulindac sulfide (E-DMSS) analogues for inhibition of COX-1. Several potent and selective inhibitors were discovered, and the most promising compounds were active against COX-1 in intact ovarian carcinoma cells (OVCAR-3). The compounds inhibited tumor cell proliferation but only at concentrations >100-fold higher than the concentrations that inhibit COX-1 activity. E-DMSS analogues may be useful probes of COX-1 biology in vivo and promising leads for COX-1-targeted therapeutic agents.

  20. Assessment of the involvement of oxidative stress and Mitogen-Activated Protein Kinase signaling pathways in the cytotoxic effects of arsenic trioxide and its combination with sulindac or its metabolites: sulindac sulfide and sulindac sulfone on human leukemic cell lines.

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    Stępnik, M; Ferlińska, M; Smok-Pieniążek, A; Gradecka-Meesters, D; Arkusz, J; Stańczyk, M

    2012-06-01

    The purpose of the study was to characterize the involvement of reactive oxygen species (ROS) in mediating the cytotoxic effects of arsenic trioxide (ATO) in combination with sulindac or its metabolites: sulfide (SS) and sulfone (SF) on human leukemic cell lines. Jurkat, HL-60, K562, and HPB-ALL cells were exposed to the drugs alone or in combinations. Cell viability was measured using WST-1 or XTT reduction tests and ROS production by dichlorodihydrofluorescein diacetate staining (flow cytometry). Modulation of (a) intracellular glutathione (GSH) level was done by using L: -buthionine sulfoximine (BSO) or diethylmaleate (DEM), (b) NADPH oxidase by using diphenyleneiodonium (DPI), and (c) MAP kinases by using SB202190 (p38), SP600125 (JNK), and U0126 (ERK) inhibitors. ATO cytotoxicity (0.5 or 1 μM) was enhanced by sulindacs, with higher activity showed by the metabolites. Strong cytotoxic effects appeared at SS and SF concentrations starting from 50 μM. The induction of ROS production seemed not to be the major mechanism responsible for the cytotoxicity of the combinations. A strong potentiating effect of BSO on ATO cytotoxicity was demonstrated; DEM (10-300 μM) and DPI (0.0025-0.1 μM; 72 h) did not influence the effects of ATO. Some significant decreases in the viability of the cells exposed to ATO in the presence of MAPK inhibitors comparing with the cells exposed to ATO alone were observed; however, the effects likely resulted from a simple additive cytotoxicity of the drugs. The combinations of ATO with sulindacs offer potential therapeutic usefulness.

  1. NOSH-sulindac (AVT-18A) is a novel nitric oxide- and hydrogen sulfide-releasing hybrid that is gastrointestinal safe and has potent anti-inflammatory, analgesic, antipyretic, anti-platelet, and anti-cancer properties.

    Science.gov (United States)

    Kashfi, Khosrow; Chattopadhyay, Mitali; Kodela, Ravinder

    2015-12-01

    Sulindac is chemopreventive and has utility in patients with familial adenomatous polyposis; however, side effects preclude its long-term use. NOSH-sulindac (AVT-18A) releases nitric oxide and hydrogen sulfide, was designed to be a safer alternative. Here we compare the gastrointestinal safety, anti-inflammatory, analgesic, anti-pyretic, anti-platelet, and anti-cancer properties of sulindac and NOSH-sulindac administered orally to rats at equimolar doses. Gastrointestinal safety: 6h post-administration, number/size of hemorrhagic lesions in stomachs were counted. Tissue samples were frozen for PGE2, SOD, and MDA determination. Anti-inflammatory: 1h after drug administration, the volume of carrageenan-induced rat paw edemas was measured for 5h. Anti-pyretic: fever was induced by LPS (ip) an hour before administration of the test drugs, core body temperature was measured hourly for 5h. Analgesic: time-dependent analgesic effects were evaluated by carrageenan-induced hyperalgesia. Antiplatelet: anti-aggregatory effects were studied on collagen-induced platelet aggregation of human platelet-rich plasma. Anti-cancer: We examined the effects of NOSH-sulindac on the growth properties of 12 human cancer cell lines of six different tissue origins. Both agents reduced PGE2 levels in stomach tissue; however, NOSH-sulindac did not cause any stomach ulcers, whereas sulindac caused significant bleeding. Lipid peroxidation induced by sulindac was higher than that from NOSH-sulindac. SOD activity was significantly lowered by sulindac but increased by NOSH-sulindac. Both agents showed similar anti-inflammatory, analgesic, anti-pyretic, and anti-platelet activities. Sulindac increased plasma TNFα whereas this rise was lower in the NOSH-sulindac-treated animals. NOSH-sulindac inhibited the growth of all cancer cell lines studied, with potencies of 1000- to 9000-fold greater than that of sulindac. NOSH-sulindac inhibited cell proliferation, induced apoptosis, and caused G2/M cell

  2. Garcinia benzophenones inhibit the growth of human colon cancer cells and synergize with sulindac sulfide and turmeric.

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    Einbond, Linda Saxe; Mighty, Jason; Kashiwazaki, Ryota; Figueroa, Mario; Jalees, Filza; Acuna, Ulyana Munoz; Le Gendre, Onica; Foster, David A; Kennelly, Edward J

    2013-12-01

    Previous studies indicate that extracts and purified components from Garcinia species inhibit the growth of human colon cancer cells. Garcinia benzophenones activate the expression of genes in the endoplasmic reticulum and cellular energy stress (mTOR) pathways. This study examines the growth inhibitory and synergistic effects of Garcinia benzophenones, alone or combined with chemopreventive agents, on human colon cancer cells. To find optimal combination treatments, HT29 colon cancer cells were treated with benzophenones alone, or combined with chemopreventive agents, and cell growth measured using the MTT assay. To reveal effects on signaling pathways, we assessed effects of the MEK inhibitor U0126 and the ER IP3 receptor antagonist heparin, as well as effects on the phosphorylation of 4E-BP-1 (mTOR pathway), using Western blot analysis. New and known benzophenones from Garcinia intermedia inhibited the growth of human colon cancer cells; an alcohol extract of Garcinia xanthochymus, as well as purified guttiferones (guttiferone E and xanthochymol), preferentially inhibited the growth of colon cancer versus nonmalignant intestinal epithelial cells. Guttiferone E exhibited synergy with the NSAID sulindac sulfide and xanthochymol, with the spice turmeric. Guttiferone A did not alter phosphorylation of 4E-BP-1, indicating that the mTORC1 pathway is not involved in its action. The effects of xanthochymol were enhanced by U0126, at low doses, and were blocked by heparin, indicating that the MEK pathway is involved, while the ER IP3 receptor is critical for its action. These studies indicate the potential of benzophenones, alone or combined with sulindac sulfide or turmeric, to prevent and treat colon cancer.

  3. Structural Mechanism of the Interaction of Alzheimer Disease Aβ Fibrils with the Non-steroidal Anti-inflammatory Drug (NSAID) Sulindac Sulfide.

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    Prade, Elke; Bittner, Heiko J; Sarkar, Riddhiman; Lopez Del Amo, Juan Miguel; Althoff-Ospelt, Gerhard; Multhaup, Gerd; Hildebrand, Peter W; Reif, Bernd

    2015-11-27

    Alzheimer disease is the most severe neurodegenerative disease worldwide. In the past years, a plethora of small molecules interfering with amyloid-β (Aβ) aggregation has been reported. However, their mode of interaction with amyloid fibers is not understood. Non-steroidal anti-inflammatory drugs (NSAIDs) are known γ-secretase modulators; they influence Aβ populations. It has been suggested that NSAIDs are pleiotrophic and can interact with more than one pathomechanism. Here we present a magic angle spinning solid-state NMR study demonstrating that the NSAID sulindac sulfide interacts specifically with Alzheimer disease Aβ fibrils. We find that sulindac sulfide does not induce drastic architectural changes in the fibrillar structure but intercalates between the two β-strands of the amyloid fibril and binds to hydrophobic cavities, which are found consistently in all analyzed structures. The characteristic Asp(23)-Lys(28) salt bridge is not affected upon interacting with sulindac sulfide. The primary binding site is located in the vicinity of residue Gly(33), a residue involved in Met(35) oxidation. The results presented here will assist the search for pharmacologically active molecules that can potentially be employed as lead structures to guide the design of small molecules for the treatment of Alzheimer disease.

  4. Sulindac sulfide reverses aberrant self-renewal of progenitor cells induced by the AML-associated fusion proteins PML/RARα and PLZF/RARα.

    Science.gov (United States)

    Steinert, Gunnar; Oancea, Claudia; Roos, Jessica; Hagemeyer, Heike; Maier, Thorsten; Ruthardt, Martin; Puccetti, Elena

    2011-01-01

    Chromosomal translocations can lead to the formation of chimeric genes encoding fusion proteins such as PML/RARα, PLZF/RARα, and AML-1/ETO, which are able to induce and maintain acute myeloid leukemia (AML). One key mechanism in leukemogenesis is increased self renewal of leukemic stem cells via aberrant activation of the Wnt signaling pathway. Either X-RAR, PML/RARα and PLZF/RARα or AML-1/ETO activate Wnt signaling by upregulating γ-catenin and β-catenin. In a prospective study, a lower risk of leukemia was observed with aspirin use, which is consistent with numerous studies reporting an inverse association of aspirin with other cancers. Furthermore, a reduction in leukemia risk was associated with use of non-steroidal anti-inflammatory drug (NSAID), where the effects on AML risk was FAB subtype-specific. To better investigate whether NSAID treatment is effective, we used Sulindac Sulfide in X-RARα-positive progenitor cell models. Sulindac Sulfide (SSi) is a derivative of Sulindac, a NSAID known to inactivate Wnt signaling. We found that SSi downregulated both β-catenin and γ-catenin in X-RARα-expressing cells and reversed the leukemic phenotype by reducing stem cell capacity and increasing differentiation potential in X-RARα-positive HSCs. The data presented herein show that SSi inhibits the leukemic cell growth as well as hematopoietic progenitors cells (HPCs) expressing PML/RARα, and it indicates that Sulindac is a valid molecular therapeutic approach that should be further validated using in vivo leukemia models and in clinical settings.

  5. Sulindac sulfide reverses aberrant self-renewal of progenitor cells induced by the AML-associated fusion proteins PML/RARα and PLZF/RARα.

    Directory of Open Access Journals (Sweden)

    Gunnar Steinert

    Full Text Available Chromosomal translocations can lead to the formation of chimeric genes encoding fusion proteins such as PML/RARα, PLZF/RARα, and AML-1/ETO, which are able to induce and maintain acute myeloid leukemia (AML. One key mechanism in leukemogenesis is increased self renewal of leukemic stem cells via aberrant activation of the Wnt signaling pathway. Either X-RAR, PML/RARα and PLZF/RARα or AML-1/ETO activate Wnt signaling by upregulating γ-catenin and β-catenin. In a prospective study, a lower risk of leukemia was observed with aspirin use, which is consistent with numerous studies reporting an inverse association of aspirin with other cancers. Furthermore, a reduction in leukemia risk was associated with use of non-steroidal anti-inflammatory drug (NSAID, where the effects on AML risk was FAB subtype-specific. To better investigate whether NSAID treatment is effective, we used Sulindac Sulfide in X-RARα-positive progenitor cell models. Sulindac Sulfide (SSi is a derivative of Sulindac, a NSAID known to inactivate Wnt signaling. We found that SSi downregulated both β-catenin and γ-catenin in X-RARα-expressing cells and reversed the leukemic phenotype by reducing stem cell capacity and increasing differentiation potential in X-RARα-positive HSCs. The data presented herein show that SSi inhibits the leukemic cell growth as well as hematopoietic progenitors cells (HPCs expressing PML/RARα, and it indicates that Sulindac is a valid molecular therapeutic approach that should be further validated using in vivo leukemia models and in clinical settings.

  6. A novel COX-independent mechanism of sulindac sulfide involves cleavage of epithelial cell adhesion molecule protein.

    Science.gov (United States)

    Liggett, Jason L; Min, Kyung-Won; Smolensky, Dmitriy; Baek, Seung Joon

    2014-08-01

    Non-steroidal anti-inflammatory drugs (NSAIDs) are extensively used over the counter to treat headaches and inflammation as well as clinically to prevent cancer among high-risk groups. The inhibition of cyclooxygenase (COX) activity by NSAIDs plays a role in their anti-tumorigenic properties. NSAIDs also have COX-independent activity which is not fully understood. In this study, we report a novel COX-independent mechanism of sulindac sulfide (SS), which facilitates a previously uncharacterized cleavage of epithelial cell adhesion molecule (EpCAM) protein. EpCAM is a type I transmembrane glycoprotein that has been implemented as an over-expressed oncogene in many cancers including colon, breast, pancreas, and prostate. We found EpCAM to be down-regulated by SS in a manner that is independent of COX activity, transcription regulation, de novo protein synthesis, and proteasomal degradation pathway. Our findings clearly demonstrate that SS drives cleavage of the extracellular portion of EpCAM near the N-terminus. This SS driven cleavage is blocked by a deleting amino acids 55-81 as well as simply mutating arginine residues at positions 80 and 81 to alanine of EpCAM. Proteolysis of EpCAM by SS may provide a novel mechanism by which NSAIDs affect anti-tumorigenesis at the post-translational level.

  7. The role of NAG-1/GDF15 in the inhibition of intestinal polyps in APC/Min mice by sulindac.

    Science.gov (United States)

    Wang, Xingya; Kingsley, Philip J; Marnett, Larry J; Eling, Thomas E

    2011-01-01

    The antitumor effects of nonsteroidal anti-inflammatory drugs (NSAID) are assumed to be due to the inhibition of COX activity, but COX-independent mechanisms may also play an important role. NSAID-activated gene (NAG-1/GDF15) is induced by NSAIDs and has antitumorigenic activities. To determine the contribution of COX-2 inhibition and NAG-1/GDF15 expression to the prevention of colon carcinogenesis by NSAIDs, we evaluated several sulindac derivatives [des-methyl (DM)-sulindac sulfide and its prodrug DM-sulindac] that do not inhibit COX-2 activity. Sulindac sulfide and DM-sulindac induced the expression of NAG-1/GDF15 in HCT116 cells as determined by quantitative real-time PCR and Western blot. We fed APC/Min mice with 320 ppm of sulindac and doses of DM-sulindac. Only sulindac significantly inhibited tumor formation inAPC/Min mice. To determine the pharmacokinetic properties of sulindac and DM-sulindac in vivo, wild-type C57/B6 mice were fed with sulindac and DM-sulindac at 80, 160, and 320 ppm. High-performance liquid chromatography analysis revealed that the conversion of DM-sulindac to DM-sulindac sulfide (active form) was less efficient than the conversion of sulindac to sulindac sulfide (active form) in the mice. Lower levels of DM-sulindac sulfide accumulated in intestinal and colon tissues in comparison with sulindac sulfide. In addition, NAG-1/GDF15 was induced in the liver of sulindac-fed mice but not in the DM-sulindac-fed mice. Collectively, our results suggest that the tumor-inhibitory effects of sulindac in APC/Min mice may be due to, in part, NAG-1/GDF15 induction in the liver. Our study also suggests that pharmacologic properties should be carefully evaluated when developing drug candidates.

  8. Sulindac sulfide inhibits sarcoendoplasmic reticulum Ca2+ ATPase, induces endoplasmic reticulum stress response, and exerts toxicity in glioma cells: relevant similarities to and important differences from celecoxib.

    Science.gov (United States)

    White, M C; Johnson, G G; Zhang, W; Hobrath, J V; Piazza, G A; Grimaldi, M

    2013-03-01

    Malignant gliomas have low survival expectations regardless of current treatments. Nonsteroidal anti-inflammatory drugs (NSAIDs) prevent cell transformation and slow cancer cell growth by mechanisms independent of cyclooxygenase (COX) inhibition. Certain NSAIDs trigger the endoplasmic reticulum stress response (ERSR), as revealed by upregulation of molecular chaperones such as GRP78 and C/EBP homologous protein (CHOP). Although celecoxib (CELE) inhibits the sarcoendoplasmic reticulum Ca(2+) ATPase (SERCA), an effect known to induce ERSR, sulindac sulfide (SS) has not been reported to affect SERCA. Here, we investigated these two drugs for their effects on Ca(2+) homeostasis, ERSR, and glioma cell survival. Our findings indicate that SS is a reversible inhibitor of SERCA and that both SS and CELE bind SERCA at its cyclopiazonic acid binding site. Furthermore, CELE releases additional Ca(2+) from the mitochondria. In glioma cells, both NSAIDS upregulate GRP78 and activate ER-associated caspase-4 and caspase-3. Although only CELE upregulates the expression of CHOP, it appears that CHOP induction could be associated with mitochondrial poisoning. In addition, CHOP induction appears to be uncorrelated with the gliotoxicity of these NSAIDS in our experiments. Our data suggest that activation of ERSR is primarily responsible for the gliotoxic effect of these NSAIDS. Because SS has good brain bioavailability, has lower COX-2 inhibition, and has no mitochondrial effects, it represents a more appealing molecular candidate than CELE to achieve gliotoxicity via activation of ERSR.

  9. The effects of cyclo-oxygenase inhibitors on bile-injured and normal equine colon.

    Science.gov (United States)

    Campbell, N B; Jones, S L; Blikslager, A T

    2002-07-01

    A potential adverse effect of cyclo-oxygenase (COX) inhibitors (nonsteroidal anti-inflammatory drugs [NSAIDs]) in horses is colitis. In addition, we have previously shown an important role for COX-produced prostanoids in recovery of ischaemic-injured equine jejunum. It was hypothesised that the nonselective COX inhibitor flunixin would retard repair of bile-injured colon by preventing production of reparative prostaglandins, whereas the selective COX-2 inhibitor, etodolac would not inhibit repair as a result of continued COX-1 activity. Segments of the pelvic flexure were exposed to 1.5 mmol/l deoxycholate for 30 min, after which they were recovered for 4 h in Ussing chambers. Contrary to the proposed hypothesis, recovery of bile-injured colonic mucosa was not affected by flunixin or etodolac, despite significantly depressed prostanoid production. However, treatment of control tissue with flunixin led to increases in mucosal permeability, whereas treatment with etodolac had no significant effect. Therefore, although recovery from bile-induced colonic injury maybe independent of COX-elaborated prostanoids, treatment of control tissues with nonselective COX inhibitors may lead to marked increases in permeability. Alternatively, selective inhibition of COX-2 may reduce the incidence of adverse effects in horses requiring NSAID therapy.

  10. Population Pharmacokinetic Model for Cancer Chemoprevention With Sulindac in Healthy Subjects

    OpenAIRE

    Berg, Alexander K.; Mandrekar, Sumithra J.; Ziegler, Katie L. Allen; Carlson, Elsa C.; Szabo, Eva; Ames, Mathew M.; Boring, Daniel; Limburg, Paul J.; Reid, Joel M.

    2013-01-01

    Sulindac is a prescription-based non-steroidal anti-inflammatory drug (NSAID) that continues to be actively investigated as a candidate cancer chemoprevention agent. To further current understanding of sulindac bioavailability, metabolism, and disposition, we developed a population pharmacokinetic model for the parent compound and its active metabolites, sulindac sulfide, and exisulind. This analysis was based on data from 24 healthy subjects who participated in a bioequivalence study compari...

  11. Population pharmacokinetic model for cancer chemoprevention with sulindac in healthy subjects.

    Science.gov (United States)

    Berg, Alexander K; Mandrekar, Sumithra J; Ziegler, Katie L Allen; Carlson, Elsa C; Szabo, Eva; Ames, Mathew M; Boring, Daniel; Limburg, Paul J; Reid, Joel M

    2013-04-01

    Sulindac is a prescription-based non-steroidal anti-inflammatory drug (NSAID) that continues to be actively investigated as a candidate cancer chemoprevention agent. To further current understanding of sulindac bioavailability, metabolism, and disposition, we developed a population pharmacokinetic model for the parent compound and its active metabolites, sulindac sulfide, and exisulind. This analysis was based on data from 24 healthy subjects who participated in a bioequivalence study comparing two formulations of sulindac. The complex disposition of sulindac and its metabolites was described by a seven-compartment model featuring enterohepatic recirculation and is the first reported population pharmacokinetic model for sulindac. The derived model was used to explore effects of clinical variables on sulindac pharmacokinetics and revealed that body weight, creatinine clearance, and gender were significantly correlated with pharmacokinetic parameters. Moreover, the model quantifies the relative bioavailability of the sulindac formulations and illustrates the utility of population pharmacokinetics in bioequivalence assessment. This novel population pharmacokinetic model provides new insights regarding the factors that may affect the pharmacokinetics of sulindac and the exisulind and sulindac sulfide metabolites in generally healthy subjects, which have implications for future chemoprevention trial design for this widely available agent.

  12. Structural analysis of sulindac as an inhibitor of aldose reductase and AKR1B10.

    Science.gov (United States)

    Cousido-Siah, Alexandra; Ruiz, Francesc X; Crespo, Isidro; Porté, Sergio; Mitschler, André; Parés, Xavier; Podjarny, Alberto; Farrés, Jaume

    2015-06-05

    Aldose reductase (AR, AKR1B1) and AKR1B10 are enzymes implicated in important pathologies (diabetes and cancer) and therefore they have been proposed as suitable targets for drug development. Sulindac is the metabolic precursor of the potent non-steroidal anti-inflammatory drug (NSAID) sulindac sulfide, which suppresses prostaglandin production by inhibition of cyclooxygenases (COX). In addition, sulindac has been found to be one of the NSAIDs with higher antitumoral activity, presumably through COX inhibition. However, sulindac anticancer activity could be partially mediated through COX-independent mechanisms, including the participation of AR and AKR1B10. Previously, it had been shown that sulindac and sulindac sulfone were good AR inhibitors and the structure of the ternary complex with NADP(+) and sulindac was described (PDB ID 3U2C). In this work, we determined the three-dimensional structure of AKR1B10 with sulindac and established structure-activity relationships (SAR) of sulindac and their derivatives with AR and AKR1B10. The difference in the IC50 values for sulindac between AR (0.36 μM) and AKR1B10 (2.7 μM) might be explained by the different positioning and stacking interaction given by Phe122/Phe123, and by the presence of two buried and ordered water molecules in AKR1B10 but not in AR. Moreover, SAR analysis shows that the substitution of the sulfinyl group is structurally allowed in sulindac derivatives. Hence, sulindac and its derivatives emerge as lead compounds for the design of more potent and selective AR and AKR1B10 inhibitors.

  13. Sulindac metabolites induce proteosomal and lysosomal degradation of the epidermal growth factor receptor.

    Science.gov (United States)

    Pangburn, Heather A; Ahnen, Dennis J; Rice, Pamela L

    2010-04-01

    The epidermal growth factor receptor (EGFR) is a member of the ErbB family of receptor tyrosine kinases. In response to ligand, EGFR is internalized and degraded by the ubiquitin-proteasome/lysosome pathway. We previously reported that metabolites of the nonsteroidal anti-inflammatory drug sulindac downregulate the expression of EGFR and inhibit basal and EGF-induced EGFR signaling through extracellular signal-regulated kinase 1/2. We now have evaluated the mechanisms of sulindac metabolite-induced downregulation of EGFR. EGF-induced downregulation of EGFR occurs within 10 minutes and lasts for 24 hours. By contrast, downregulation of EGFR by sulindac sulfide and sulindac sulfone was first evident at 4 and 24 hours, respectively, with maximal downregulation at 72 hours. Pretreatment with either the lysosomal inhibitor chloroquine or the proteosomal inhibitor MG132 blocked sulindac metabolite-induced downregulation of EGFR. Sulindac metabolites also increased the ubiquitination of EGFR. Whereas sulindac metabolites inhibited phosphorylation of EGFR pY1068, they increased phosphorylation of EGFR pY1045, the docking site where c-Cbl binds, thereby enabling receptor ubiquitination and degradation. Immunofluorescence analysis of EGF and EGFR distribution confirmed the biochemical observations that sulindac metabolites alter EGFR localization and EGFR internalization in a manner similar to that seen with EGF treatment. Expression of ErbB family members HER2 and HER3 was also downregulated by sulindac metabolites. We conclude that downregulation of EGFR expression by sulindac metabolites is mediated via lysosomal and proteosomal degradation that may be due to drug-induced phosphorylation at pY1045 with resultant ubiquitination of EGFR. Thus, sulindac metabolite-induced downregulation of EGFR seems to be mediated through mechanism(s) similar, at least in part, to those involved in EGF-induced downregulation of EGFR.

  14. Studies on the metabolism and biological activity of the epimers of sulindac.

    Science.gov (United States)

    Brunell, David; Sagher, Daphna; Kesaraju, Shailaja; Brot, Nathan; Weissbach, Herbert

    2011-06-01

    Sulindac is a nonsteroidal, anti-inflammatory drug (NSAID) that has also been studied for its anticancer activity. Recent studies suggest that sulindac and its metabolites act by sensitizing cancer cells to oxidizing agents and drugs that affect mitochondrial function, resulting in the production of reactive oxygen species and death by apoptosis. In contrast, normal cells are not killed under these conditions and, in some instances, are protected against oxidative stress. Sulindac has a methyl sulfoxide moiety with a chiral center and was used in all of the previous studies as a mixture of the R- and S-epimers. Because epimers of a compound can have very different chemical and biological properties, we have separated the R- and S-epimers of sulindac, studied their individual metabolism, and performed preliminary experiments on their effect on normal and lung cancer cells exposed to oxidative stress. Previous results had indicated that the reduction of (S)-sulindac to sulindac sulfide, the active NSAID, was catalyzed by methionine sulfoxide reductase (Msr) A. In the present study, we purified an enzyme that reduces (R)-sulindac and resembles MsrB in its substrate specificity. The oxidation of both epimers to sulindac sulfone is catalyzed primarily by the microsomal cytochrome P450 (P450) system, and the individual enzymes responsible have been identified. (S)-Sulindac increases the activity of the P450 system better than (R)-sulindac, but both epimers increase primarily the enzymes that oxidize (R)-sulindac. Both epimers can protect normal lung cells against oxidative damage and enhance the killing of lung cancer cells exposed to oxidative stress.

  15. Sulindac and its metabolites inhibit multiple transport proteins in rat and human hepatocytes.

    Science.gov (United States)

    Lee, Jin Kyung; Paine, Mary F; Brouwer, Kim L R

    2010-08-01

    Sulindac is a commonly used nonsteroidal anti-inflammatory drug. This study tested the hypothesis that sulindac-mediated drug-drug interactions and/or hepatotoxicity may be caused, in part, by inhibition of proteins responsible for the hepatic transport of drugs and/or bile acids by sulindac and/or sulindac metabolites [sulindac sulfone (S-sulfone) and sulindac sulfide (S-sulfide)]. The uptake and excretion of model substrates, [(3)H]taurocholate (TC), [(3)H]estradiol 17-beta-glucuronide (E217G), and nitrofurantoin (NF), were investigated in rat and human suspended and sandwich-cultured hepatocytes (SCH). In suspended rat hepatocytes, S-sulfone and S-sulfide inhibited Na(+)-dependent TC initial uptake (IC(50) of 24.9 +/- 6.4 and 12.5 +/- 1.8 microM, respectively) and Na(+)-independent E217G initial uptake (IC(50) of 12.1 +/- 1.6 and 6.3 +/- 0.3 microM, respectively). In rat SCH, sulindac metabolites (100 microM) decreased the in vitro biliary clearance (Cl(biliary)) of TC, E217G, and NF by 38 to 83%, 81 to 97%, and 33 to 57%, respectively; S-sulfone and S-sulfide also decreased the TC and NF biliary excretion index by 39 to 55%. In suspended human hepatocytes, S-sulfone and S-sulfide inhibited Na(+)-dependent TC initial uptake (IC(50) of 42.2 and 3.1 microM, respectively); S-sulfide also inhibited the TC Cl(biliary) in human SCH. Sulindac/metabolites markedly inhibited hepatic uptake and biliary excretion of E217G by 51 to 100% in human SCH. In conclusion, sulindac and metabolites are potent inhibitors of the uptake and biliary clearance of bile acids in rat and human hepatocytes and also inhibit substrates of rat breast cancer resistance protein, rat and human organic anion-transporting polypeptides, and human multidrug resistance-associated protein 2. Inhibition of multiple hepatic transport proteins by sulindac/metabolites may play an important role in clinically significant sulindac-mediated drug-drug interactions and/or liver injury.

  16. Synergistic cytotoxic effect of sulindac and pyrrolidine dithiocarbamate against ovarian cancer cells.

    Science.gov (United States)

    Jakubowska-Mućka, Anna; Sieńko, Jacek; Zapała, Łukasz; Wolny, Rafał; Lasek, Witold

    2012-04-01

    Sulindac, a non-steroidal anti-inflammatory drug, suppresses carcinogenesis and inhibits growth of tumor cells. Pyrrolidine dithiocarbamate (PDTC), a potent NF-κB inhibitor, has been also identified as a potential anti-neoplastic agent. We hypothesized that combination of sulindac and PDTC could result in augmentation of cytotoxicity against ovarian cancer cells. The effect of sulindac and PDTC was examined on several ovarian cancer lines. Tumor cell viability was assessed using the MTT assay. Annexin-V/PI staining was used to detect apoptosis, cell cycle distribution was analyzed in FACS, and expression of cellular proteins was detected by western blotting. Incubation of OVA-14, OVP-10 and CAOV-1 ovarian cancer cells with sulindac and PDTC resulted in significantly greater inhibition of cell viability compared to either compound alone. In a model of OVA-14 cells it was evident that this effect was not related to the expression of COX enzymes since both active (sulindac sulfide) and inactive (sulindac) in vitro compounds affected the growth of tumor cells to a similar extent and synergized in cytotoxicity with PDTC. Combination of sulindac and PDTC lead to G0 arrest and massive apoptosis in co-treated cultures. Western blotting analysis argued for induction of the mitochondrial apoptotic pathway. These data demonstrate the synergistic cytotoxic effect of sulindac and PDTC on ovarian cancer cells through apoptosis and cell cycle arrest and prompt to test the efficacy of this combination in animal models.

  17. Sulindac metabolites inhibit epidermal growth factor receptor activation and expression

    Directory of Open Access Journals (Sweden)

    Pangburn Heather A

    2005-09-01

    Full Text Available Abstract Background Regular use of nonsteroidal anti-inflammatory drugs (NSAIDs is associated with a decreased mortality from colorectal cancer (CRC. NSAIDs induce apoptotic cell death in colon cancer cells in vitro and inhibit growth of neoplastic colonic mucosa in vivo however, the biochemical mechanisms required for these growth inhibitory effects are not well defined. We previously reported that metabolites of the NSAID sulindac downregulate extracellular-signal regulated kinase 1/2 (ERK1/2 signaling and that this effect is both necessary and sufficient for the apoptotic effects of these drugs. The goal of this project was to specifically test the hypothesis that sulindac metabolites block activation and/or expression of the epidermal growth factor (EGF receptor (EGFR. Methods HT29 human colon cancer cells were treated with EGF, alone, or in the presence of sulindac sulfide or sulindac sulfone. Cells lysates were assayed by immunoblotting for phosphorylated EGFR (pEGFR, pY1068, total EGFR, phosphorylated ERK1/2 (pERK1/2, total ERK1/2, activated caspase-3, and α-tubulin. Results EGF treatment rapidly induced phosphorylation of both EGFR and ERK1/2 in HT29 colon cancer cells. Pretreatment with sulindac metabolites for 24 h blocked EGF-induced phosphorylation of both EGFR and ERK1/2 and decreased total EGFR protein expression. Under basal conditions, downregulation of pEGFR and total EGFR was detected as early as 12 h following sulindac sulfide treatment and persisted through at least 48 h. Sulindac sulfone induced downregulation of pEGFR and total EGFR was detected as early as 1 h and 24 h, respectively, following drug treatment, and persisted through at least 72 h. EGFR downregulation by sulindac metabolites was observed in three different CRC cell lines, occurred prior to the observed downregulation of pERK1/2 and induction of apoptosis by these drugs, and was not dependent of caspase activation. Conclusion These results suggest that

  18. Effects of non-selective (piroxicam and selective (meloxicam cyclo-oxygenase inhibitors on the intestinal contractility of rabbits

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    Warida M. El-Rwegi

    2015-10-01

    Conclusions: Data of the present study may indicate that piroxicam and meloxicam could be used effectively and safely in rabbits for their anti-inflammatory actions in small therapeutic doses. However, in large doses, they (particularly, piroxicam may produce depressant effects on gastrointestinal tract motility that should be taken in consideration in the case of introducing these drugs in therapy with larger doses [Int J Basic Clin Pharmacol 2015; 4(5.000: 924-930

  19. Intervening in β-catenin signaling by sulindac inhibits S100A4-dependent colon cancer metastasis.

    Science.gov (United States)

    Stein, Ulrike; Arlt, Franziska; Smith, Janice; Sack, Ulrike; Herrmann, Pia; Walther, Wolfgang; Lemm, Margit; Fichtner, Iduna; Shoemaker, Robert H; Schlag, Peter M

    2011-02-01

    Colon cancer metastasis is often associated with activation of the Wnt/β-catenin signaling pathway and high expression of the metastasis mediator S100A4. We previously demonstrated the transcriptional regulation of S100A4 by β-catenin and the importance of the interconnection of these cellular programs for metastasis. Here we probe the hypothesis that the nonsteroidal anti-inflammatory drug sulindac sulfide can inhibit colon cancer metastasis by intervening in β-catenin signaling and thereby interdicting S100A4. We treated colon cancer cell lines heterozygous for gain-of-function and wild-type β-catenin with sulindac. We analyzed sulindac's effects on β-catenin expression and subcellular localization, β-catenin binding to the T-cell factor (TCF)/S100A4 promoter complex, S100A4 promoter activity, S100A4 expression, cell motility, and proliferation. Mice intrasplenically transplanted with S100A4-overexpressing colon cancer cells were treated with sulindac. Tumor growth and metastasis, and their β-catenin and S100A4 expressions, were determined. We report the expression knockdown of β-catenin by sulindac, leading to its reduced nuclear accumulation. The binding of β-catenin to TCF was clearly lowered, resulting in reduced S100A4 promoter activity and expression. This correlated well with the inhibition of cell migration and invasion, which could be rescued by ectopic S100A4 expression. In mice, sulindac treatment resulted in reduced tumor growth in the spleen (P = .014) and decreased liver metastasis in a human colon cancer xenograft model (P = .025). Splenic tumors and liver metastases of sulindac-treated mice showed lowered β-catenin and S100A4 levels. These results suggest that modulators of β-catenin signaling such as sulindac offer potential as antimetastatic agents by interdicting S100A4 expression.

  20. Intervening in β-Catenin Signaling by Sulindac Inhibits S100A4-Dependent Colon Cancer Metastasis

    Directory of Open Access Journals (Sweden)

    Ulrike Stein

    2011-02-01

    Full Text Available Colon cancer metastasis is often associated with activation of the Wnt/β-catenin signaling pathway and high expression of the metastasis mediator S100A4. We previously demonstrated the transcriptional regulation of S100A4 by β-catenin and the importance of the interconnection of these cellular programs for metastasis. Here we probe the hypothesis that the nonsteroidal anti-inflammatory drug sulindac sulfide can inhibit colon cancer metastasis by intervening in β-catenin signaling and thereby interdicting S100A4. We treated colon cancer cell lines heterozygous for gain-of-function and wild-type β-catenin with sulindac. We analyzed sulindac's effects on β-catenin expression and subcellular localization, β-catenin binding to the T-cell factor (TCF/S100A4 promoter complex, S100A4 promoter activity, S100A4 expression, cell motility, and proliferation. Mice intrasplenically transplanted with S100A4-overexpressing colon cancer cells were treated with sulindac. Tumor growth and metastasis, and their β-catenin and S100A4 expressions, were determined. We report the expression knockdown of β-catenin by sulindac, leading to its reduced nuclear accumulation. The binding of β-catenin to TCF was clearly lowered, resulting in reduced S100A4 promoter activity and expression. This correlated well with the inhibition of cell migration and invasion, which could be rescued by ectopic S100A4 expression. In mice, sulindac treatment resulted in reduced tumor growth in the spleen (P = .014 and decreased liver metastasis in a human colon cancer xenograft model (P = .025. Splenic tumors and liver metastases of sulindac-treated mice showed lowered β-catenin and S100A4 levels. These results suggest that modulators of β-catenin signaling such as sulindac offer potential as antimetastatic agents by interdicting S100A4 expression.

  1. A novel sulindac derivative lacking cyclooxygenase-inhibitory activities suppresses carcinogenesis in the transgenic adenocarcinoma of mouse prostate model.

    Science.gov (United States)

    Zhang, Yong; Zhang, Jinhui; Wang, Lei; Quealy, Emily; Gary, Bernard D; Reynolds, Robert C; Piazza, Gary A; Lü, Junxuan

    2010-07-01

    Nonsteroidal anti-inflammatory drugs including sulindac are well documented to be highly effective for cancer chemoprevention. However, their cyclooxygenase (COX)-inhibitory activities cause severe gastrointestinal, renal, and cardiovascular toxicities, limiting their chronic use. Recent studies suggest that COX-independent mechanisms may be responsible for the chemopreventive benefits of nonsteroidal anti-inflammatory drugs and support the potential for the development of a novel generation of sulindac derivatives lacking COX inhibition for cancer chemoprevention. A prototypic sulindac derivative with a N,N-dimethylammonium substitution called sulindac sulfide amide (SSA) was recently identified to be devoid of COX-inhibitory activity yet displays much more potent tumor cell growth-inhibitory activity in vitro compared with sulindac sulfide. In this study, we investigated the androgen receptor (AR) signaling pathway as a potential target for its COX-independent antineoplastic mechanism and evaluated its chemopreventive efficacy against prostate carcinogenesis using the transgenic adenocarcinoma of mouse prostate model. The results showed that SSA significantly suppressed the growth of human and mouse prostate cancer cells expressing AR in strong association with G(1) arrest, and decreased AR level and AR-dependent transactivation. Dietary SSA consumption dramatically attenuated prostatic growth and suppressed AR-dependent glandular epithelial lesion progression through repressing cell proliferation in the transgenic adenocarcinoma of mouse prostate mice, whereas it did not significantly affect neuroendocrine carcinoma growth. Overall, the results suggest that SSA may be a chemopreventive candidate against prostate glandular epithelial carcinogenesis.

  2. The Role of NAG-1/GDF15 in the Inhibition of Intestinal Polyps in APC/Min Mice by Sulindac

    OpenAIRE

    Wang, Xingya; Kingsley, Philip J.; Marnett, Larry J.; Thomas E Eling

    2011-01-01

    The antitumor effects of nonsteroidal anti-inflammatory drugs (NSAID) are assumed to be due to the inhibition of COX activity, but COX-independent mechanisms may also play an important role. NSAID-activated gene (NAG-1/GDF15) is induced by NSAIDs and has antitumorigenic activities. To determine the contribution of COX-2 inhibition and NAG-1/GDF15 expression to the prevention of colon carcinogenesis by NSAIDs, we evaluated several sulindac derivatives [des-methyl (DM)-sulindac sulfide and its ...

  3. Sulindac derivatives inhibit cell growth and induce apoptosis in primary cells from malignant peripheral nerve sheath tumors of NF1-patients

    Directory of Open Access Journals (Sweden)

    Friedrich Reinhard E

    2004-05-01

    Full Text Available Abstract Background Malignant peripheral nerve sheath tumors (MPNSTs are neoplasms leading to death in most cases. Patients with Neurofibromatosis type 1 have an increased risk of developing this malignancy. The metabolites of the inactive prodrug Sulindac, Sulindac Sulfide and Sulindac Sulfone (Exisulind are new chemopreventive agents that show promising results in the treatment of different cancer types. In this study we examined the antineoplastic effect of these compounds on primary cells derived from two MPNSTs of Neurofibromatosis type 1 patients. Results Exisulind and Sulindac Sulfide showed a dramatic time- and dose-dependent growth inhibitory effect with IC50-values of 120 μM and 63 μM, respectively. The decrease in viability of the tested cells correlated with induction of apoptosis. Treatment with 500 μM Exisulind and 125 μM Sulindac Sulfide for a period of 2 days increased the rate of apoptosis 21-27-fold compared to untreated cells. Reduced expression of RAS-GTP and phosphorylated ERK1/2 was detected in treated MPNST cells. Moreover, elevated levels of phosphorylated SAPK/JNK were found after drug treatment, and low activation of cleaved caspase-3 was seen. Conclusions Our results suggest that this class of compounds may be of therapeutic benefit for Neurofibromatosis type 1 patients with MPNST.

  4. Sulindac metabolites decrease cerebrovascular malformations in CCM3-knockout mice.

    Science.gov (United States)

    Bravi, Luca; Rudini, Noemi; Cuttano, Roberto; Giampietro, Costanza; Maddaluno, Luigi; Ferrarini, Luca; Adams, Ralf H; Corada, Monica; Boulday, Gwenola; Tournier-Lasserve, Elizabeth; Dejana, Elisabetta; Lampugnani, Maria Grazia

    2015-07-07

    Cerebral cavernous malformation (CCM) is a disease of the central nervous system causing hemorrhage-prone multiple lumen vascular malformations and very severe neurological consequences. At present, the only recommended treatment of CCM is surgical. Because surgery is often not applicable, pharmacological treatment would be highly desirable. We describe here a murine model of the disease that develops after endothelial-cell-selective ablation of the CCM3 gene. We report an early, cell-autonomous, Wnt-receptor-independent stimulation of β-catenin transcription activity in CCM3-deficient endothelial cells both in vitro and in vivo and a triggering of a β-catenin-driven transcription program that leads to endothelial-to-mesenchymal transition. TGF-β/BMP signaling is then required for the progression of the disease. We also found that the anti-inflammatory drugs sulindac sulfide and sulindac sulfone, which attenuate β-catenin transcription activity, reduce vascular malformations in endothelial CCM3-deficient mice. This study opens previously unidentified perspectives for an effective pharmacological therapy of intracranial vascular cavernomas.

  5. Compound list: sulindac [Open TG-GATEs

    Lifescience Database Archive (English)

    Full Text Available sulindac SUL 00100 ftp://ftp.biosciencedbc.jp/archive/open-tggates/LATEST/Human/in_vitro/suli...ndac.Human.in_vitro.Liver.zip ftp://ftp.biosciencedbc.jp/archive/open-tggates/LATEST/Rat/in_vitro/suli...ndac.Rat.in_vitro.Liver.zip ftp://ftp.biosciencedbc.jp/archive/open-tggates/LATEST/Rat/in_vivo/Liver/Single/suli...-tggates/LATEST/Rat/in_vivo/Liver/Repeat/sulindac.Rat.in_vivo.Liver.Repeat.zip ...

  6. Therapeutic potential of sulindac hydroxamic acid against human pancreatic and colonic cancer cells.

    Science.gov (United States)

    Fogli, Stefano; Banti, Irene; Stefanelli, Fabio; Picchianti, Luca; Digiacomo, Maria; Macchia, Marco; Breschi, Maria Cristina; Lapucci, Annalina

    2010-11-01

    The non-steroidal anti-inflammatory drug (NSAID) sulindac exhibits cyclooxygenase (COX)-dependent and COX-independent chemopreventive properties in human cancer. The present study was aimed at investigating whether the hydroxamic acid substitution for the carboxylic acid group could enhance the in vitro antitumor and antiangiogenic activities of sulindac. Characterization tools used on this study included analyses of cell viability, caspase 3/7 induction, DNA fragmentation, and gene expression. Our findings demonstrate that the newly synthesized hydroxamic acid derivative of sulindac and its sulfone and sulfide metabolites were characterized by a good anticancer activity on human pancreatic and colon cancer cells, both in terms of potency (IC(50) mean values from 6 ± 1.1 μM to 64 ± 1.1 μM) and efficacy (E(max) of ∼100%). Hydroxamic acid derivatives trigger a higher degree of apoptosis than carboxylic acid counterparts, increase bax/bcl-2 expression ratio and induce caspase 3/7 activation. Most notably, these compounds significantly inhibit proangiogenic growth factor-stimulated proliferation of vascular endothelial cell (HUVEC) at sub-micromolar concentrations. Our data also provide evidence that the COX-active metabolite of sulindac hydroxamic acid were the most active of the series and selective inhibition of COX-1 but not COX-2 can mimic its effects, suggesting that COX inhibition could only play a partial role in the mechanism of compound action. In conclusion, these data demonstrate that substitution of the carboxylic acid group with the hydroxamic acid moiety enhances in vitro antiproliferative, proapoptotic and antiangiogenic properties of sulindac, therefore increasing the therapeutic potential of this drug.

  7. Sulindac induces apoptosis and protects against colon carcinoma in mice

    Institute of Scientific and Technical Information of China (English)

    Bao-Cun Sun; Xiu-Lan Zhao; Shi-Wu Zhang; Yi-Xin Liu; Lan Wang; Xin Wang

    2005-01-01

    AIM: To study the effect of sulindac on colon cancer induction in mice.METHODS: The chemo-preventive action of 80 ppm sulindac fed during initiation and post-initiation and 100 ppm sulindac fed during progressive stages of induction of colon carcinogenesis in mice was investigated using 1,2-dimethylhydrazine (DMH). Using the terminal deoxynucleotidyltransferase-mediated dUTP nick-end labeling (TUNEL)technique and PCNA immunohistochemical staining, we observed the apoptotic and proliferative cell density changes at different carcinogenic stages and the effect of sulindac on these two phenomena.RESULTS: Dietary sulindac significantly inhibited the incidence of colonic neoplasmas in mice. Compared with the control group, feeding sulindac during initiation and post-initiation stages inhibited the incidence by 46.7-50.4%,and feeding sulindac during progressive stages inhibited the incidence by 41.1%. Animals that were fed sulindac showed less serious pathological changes than those that were fed the control diet (P<0.01, H= 33.35). There was no difference in the density of proliferating cells among those groups which were or were not fed sulindac. In the same period, feeding sulindac resulted in a higher density of apoptotic cells than feeding control diet. CONCLUSION: Sulindac has an anti-carcinogenic function in mice. Its effect on preventing colon carcinogenesis is better than its effect on treating established tumors. By inducing apoptosis, sulindac inhibited the development of colon cancer and delayed canceration. Sulindac has no effect on proliferation. The anti-carcinogenic properties of sulindac are most effective in the moderate and severe stages of dysplasia and canceration.

  8. Sulindac selectively inhibits colon tumor cell growth by activating the cGMP/PKG pathway to suppress Wnt/β-catenin signaling.

    Science.gov (United States)

    Li, Nan; Xi, Yaguang; Tinsley, Heather N; Gurpinar, Evrim; Gary, Bernard D; Zhu, Bing; Li, Yonghe; Chen, Xi; Keeton, Adam B; Abadi, Ashraf H; Moyer, Mary P; Grizzle, William E; Chang, Wen-Chi; Clapper, Margie L; Piazza, Gary A

    2013-09-01

    Nonsteroidal anti-inflammatory drugs (NSAID) display promising antineoplastic activity for colorectal and other cancers, but toxicity from COX inhibition limits their long-term use for chemoprevention. Previous studies have concluded that the basis for their tumor cell growth inhibitory activity does not require COX inhibition, although the underlying mechanism is poorly understood. Here, we report that the NSAID sulindac sulfide inhibits cyclic guanosine 3',5'-monophosphate phosphodiesterase (cGMP PDE) activity to increase intracellular cGMP levels and activate cGMP-dependent protein kinase (PKG) at concentrations that inhibit proliferation and induce apoptosis of colon tumor cells. Sulindac sulfide did not activate the cGMP/PKG pathway, nor affect proliferation or apoptosis in normal colonocytes. Knockdown of the cGMP-specific PDE5 isozyme by siRNA and PDE5-specific inhibitors tadalafil and sildenafil also selectively inhibited the growth of colon tumor cells that expressed high levels of PDE5 compared with colonocytes. The mechanism by which sulindac sulfide and the cGMP/PKG pathway inhibits colon tumor cell growth involves the transcriptional suppression of β-catenin to inhibit Wnt/β-catenin T-cell factor transcriptional activity, leading to downregulation of cyclin D1 and survivin. These observations suggest that safer and more efficacious sulindac derivatives can be developed for colorectal cancer chemoprevention by targeting PDE5 and possibly other cGMP-degrading isozymes.

  9. The molecular basis for inhibition of sulindac and its metabolites towards human aldose reductase.

    Science.gov (United States)

    Zheng, Xuehua; Zhang, Liping; Zhai, Jing; Chen, Yunyun; Luo, Haibin; Hu, Xiaopeng

    2012-01-02

    Sulindac (SLD) exhibits both the highest inhibitory activity towards human aldose reductase (AR) among popular non-steroidal anti-inflammatory drugs and clear beneficial clinical effects on Type 2 diabetes. However, the molecular basis for these properties is unclear. Here, we report that SLD and its pharmacologically active/inactive metabolites, SLD sulfide and SLD sulfone, are equally effective as un-competitive inhibitors of AR in vitro. Crystallographic analysis reveals that π-π stacking favored by the distinct scaffold of SLDs is pivotal to their high AR inhibitory activities. These results also suggest that SLD sulfone could be a potent lead compound for AR inhibition in vivo.

  10. Suppression of growth arrest and DNA damage-inducible 45alpha expression confers resistance to sulindac and indomethacin-induced gastric mucosal injury.

    Science.gov (United States)

    Chiou, Shiun-Kwei; Hodges, Amy; Hoa, Neil

    2010-09-01

    Nonsteroidal anti-inflammatory drugs (NSAIDs) such as sulindac and indomethacin are a major cause of gastric erosions and ulcers. Induction of apoptosis by NSAIDs is an important mechanism involved. Understanding how NSAIDs affect genes that regulate apoptosis is useful for designing therapeutic or preventive strategies and for evaluating the efficacy of safer drugs being developed. We investigated whether growth arrest and DNA damage-inducible 45alpha (GADD45alpha), a stress signal response gene involved in regulation of DNA repair and induction of apoptosis, plays a part in NSAID-induced gastric mucosal injury and apoptosis in vivo in mice and in vitro in cultured human AGS and rat RGM-1 gastric epithelial cells. Intraperitoneal administration of sulindac and indomethacin both resulted in up-regulation of GADD45alpha expression and induction of significant injury and apoptosis in gastric mucosa of wild-type mice. GADD45alpha(-/-) mice were markedly more resistant to both sulindac- and indomethacin-induced gastric mucosal injury and apoptosis than wild-type mice. Sulindac sulfide and indomethacin treatments also concentration-dependently increased GADD45alpha expression and apoptosis in AGS and RGM-1 cells. Antisense suppression of GADD45alpha expression significantly reduced sulindac and indomethacin-induced activation of caspase-9 and apoptosis in AGS cells. Pretreatments with exogenous prostaglandins and small interfering RNA suppression of cyclooxygenase (COX)-1 and -2 did not affect up-regulation of GADD45alpha by sulindac sulfide and indomethacin in AGS cells. These findings indicate that GADD45alpha up-regulation is a COX-independent mechanism that is required for induction of severe gastric mucosal apoptosis and injury by NSAIDs, probably via a capase-9-dependent pathway of programmed cell death.

  11. Sulindac compounds facilitate the cytotoxicity of β-lapachone by up-regulation of NAD(P)H quinone oxidoreductase in human lung cancer cells.

    Science.gov (United States)

    Kung, Hsiu-Ni; Weng, Tsai-Yun; Liu, Yu-Lin; Lu, Kuo-Shyan; Chau, Yat-Pang

    2014-01-01

    β-lapachone, a major component in an ethanol extract of Tabebuia avellanedae bark, is a promising potential therapeutic drug for various tumors, including lung cancer, the leading cause of cancer-related deaths worldwide. In the first part of this study, we found that apoptotic cell death induced in lung cancer cells by high concentrations of β-lapachone was mediated by increased activation of the pro-apoptotic factor JNK and decreased activation of the cell survival/proliferation factors PI3K, AKT, and ERK. In addition, β-lapachone toxicity was positively correlated with the expression and activity of NAD(P)H quinone oxidoreductase 1 (NQO1) in the tumor cells. In the second part, we found that the FDA-approved non-steroidal anti-inflammatory drug sulindac and its metabolites, sulindac sulfide and sulindac sulfone, increased NQO1 expression and activity in the lung adenocarcinoma cell lines CL1-1 and CL1-5, which have lower NQO1 levels and lower sensitivity to β-lapachone treatment than the A549 cell lines, and that inhibition of NQO1 by either dicoumarol treatment or NQO1 siRNA knockdown inhibited this sulindac-induced increase in β-lapachone cytotoxicity. In conclusion, sulindac and its metabolites synergistically increase the anticancer effects of β-lapachone primarily by increasing NQO1 activity and expression, and these two drugs may provide a novel combination therapy for lung cancers.

  12. Sulindac compounds facilitate the cytotoxicity of β-lapachone by up-regulation of NAD(PH quinone oxidoreductase in human lung cancer cells.

    Directory of Open Access Journals (Sweden)

    Hsiu-Ni Kung

    Full Text Available β-lapachone, a major component in an ethanol extract of Tabebuia avellanedae bark, is a promising potential therapeutic drug for various tumors, including lung cancer, the leading cause of cancer-related deaths worldwide. In the first part of this study, we found that apoptotic cell death induced in lung cancer cells by high concentrations of β-lapachone was mediated by increased activation of the pro-apoptotic factor JNK and decreased activation of the cell survival/proliferation factors PI3K, AKT, and ERK. In addition, β-lapachone toxicity was positively correlated with the expression and activity of NAD(PH quinone oxidoreductase 1 (NQO1 in the tumor cells. In the second part, we found that the FDA-approved non-steroidal anti-inflammatory drug sulindac and its metabolites, sulindac sulfide and sulindac sulfone, increased NQO1 expression and activity in the lung adenocarcinoma cell lines CL1-1 and CL1-5, which have lower NQO1 levels and lower sensitivity to β-lapachone treatment than the A549 cell lines, and that inhibition of NQO1 by either dicoumarol treatment or NQO1 siRNA knockdown inhibited this sulindac-induced increase in β-lapachone cytotoxicity. In conclusion, sulindac and its metabolites synergistically increase the anticancer effects of β-lapachone primarily by increasing NQO1 activity and expression, and these two drugs may provide a novel combination therapy for lung cancers.

  13. Topical sulindac therapy in diabetic senile cataracts : cataract IV

    Directory of Open Access Journals (Sweden)

    Sharma Y

    1989-01-01

    Full Text Available Sulindac, a non-steroidal anti-inflammatory drug has been found to be a potent inhibitor of enzyme aldose reductase. We used sulindac topically in diabetic senile cataract patients to note if it effects the progression of cataracts. More of sulindac treated eyes maintained initial vision and fewer eyes had visual loss of up to two lines or more as compared to control eyes. The extent and density of different opacities showed less progression in sulindac treated eyes but it was not statistically significant except that the ophthalmoscopically observed density of opacity showed statistically very significant lesser mean increase in sulindac treated eyes. We suggest that sulindac is a potential drug which should be further evaluated in large double blind photodocumented studies in diabetic senile cataracts.

  14. Sulindac Prevents Esophageal Adenocarcinomas Induced by Gastroduodenal Reflux in Rats

    OpenAIRE

    Kim, Sung Wook; Jang, Tae Jung; Jung, Ki Hoon; Suh, Jung Il

    2007-01-01

    Purpose It is known that cyclooxygenase (COX)-2 expression is increased in Barrett's esophagus and esophageal adenocarcinomas. We studied COX-2 expression and the effect sulindac has on the genesis of Barrett's esophagus and adenocarcinoma in rats undergoing esophagogastroduodenal anastomosis (EGDA). Materials and Methods Fifty-one rats were divided into a control group (n = 27), a 500 ppm sulindac-treated group (n = 15) and 1000 ppm sulindac-treated group (n = 9). Randomly selected rats were...

  15. Aerosol administration of phospho-sulindac inhibits lung tumorigenesis.

    Science.gov (United States)

    Cheng, Ka Wing; Wong, Chi C; Alston, Ninche; Mackenzie, Gerardo G; Huang, Liqun; Ouyang, Nengtai; Xie, Gang; Wiedmann, Timothy; Rigas, Basil

    2013-08-01

    Phospho-sulindac is a sulindac derivative with promising anticancer activity in lung cancer, but its limited metabolic stability presents a major challenge for systemic therapy. We reasoned that inhalation delivery of phospho-sulindac might overcome first-pass metabolism and produce high levels of intact drug in lung tumors. Here, we developed a system for aerosolization of phospho-sulindac and evaluated the antitumor efficacy of inhaled phospho-sulindac in an orthotopic model of human non-small cell lung cancer (A549 cells). We found that administration by inhalation delivered high levels of phospho-sulindac to the lungs and minimized its hydrolysis to less active metabolites. Consequently, inhaled phospho-sulindac (6.5 mg/kg) was highly effective in inhibiting lung tumorigenesis (75%; P sulindac suppressed lung tumorigenesis by (i) inhibiting EGF receptor (EGFR) activation, leading to profound inhibition of Raf/MEK/ERK and PI3K/AKT/mTOR survival cascades; (ii) inducing oxidative stress, which provokes the collapse of mitochondrial membrane potential and mitochondria-dependent cell death; and (iii) inducing autophagic cell death. Our data establish that inhalation delivery of phospho-sulindac is an efficacious approach to the control of lung cancer, which merits further evaluation.

  16. A novel sulindac derivative inhibits lung adenocarcinoma cell growth through suppression of Akt/mTOR signaling and induction of autophagy.

    Science.gov (United States)

    Gurpinar, Evrim; Grizzle, William E; Shacka, John J; Mader, Burton J; Li, Nan; Piazza, Nicholas A; Russo, Suzanne; Keeton, Adam B; Piazza, Gary A

    2013-05-01

    Nonsteroidal anti-inflammatory drugs such as sulindac sulfide have shown promising antineoplastic activity in multiple tumor types, but toxicities resulting from COX inhibition limit their use in cancer therapy. We recently described a N,N-dimethylethyl amine derivative of sulindac sulfide, sulindac sulfide amide (SSA), that does not inhibit COX-1 or -2, yet displays potent tumor cell growth-inhibitory activity. Here, we studied the basis for the growth-inhibitory effects of SSA on human lung adenocarcinoma cell lines. SSA potently inhibited the growth of lung tumor cells with IC50 values of 2 to 5 μmol/L compared with 44 to 52 μmol/L for sulindac sulfide. SSA also suppressed DNA synthesis and caused a G0-G1 cell-cycle arrest. SSA-induced cell death was associated with characteristics of autophagy, but significant caspase activation or PARP cleavage was not observed after treatment at its IC50 value. siRNA knockdown of Atg7 attenuated SSA-induced autophagy and cell death, whereas pan-caspase inhibitor ZVAD was not able to rescue viability. SSA treatment also inhibited Akt/mTOR signaling and the expression of downstream proteins that are regulated by this pathway. Overexpression of a constitutively active form of Akt was able to reduce autophagy markers and confer resistance to SSA-induced cell death. Our findings provide evidence that SSA inhibits lung tumor cell growth by a mechanism involving autophagy induction through the suppression of Akt/mTOR signaling. This unique mechanism of action, along with its increased potency and lack of COX inhibition, supports the development of SSA or related analogs for the prevention and/or treatment of lung cancer.

  17. The in vitro metabolism of phospho-sulindac amide, a novel potential anticancer agent.

    Science.gov (United States)

    Xie, Gang; Cheng, Ka-Wing; Huang, Liqun; Rigas, Basil

    2014-09-15

    Phospho-sulindac amide (PSA) is a novel potential anti-cancer and anti-inflammatory agent. Here we report the metabolism of PSA in vitro. PSA was rapidly hydroxylated at its butane-phosphate moiety to form two di-hydroxyl-PSA and four mono-hydroxyl-PSA metabolites in mouse and human liver microsomes. PSA also can be oxidized or reduced at its sulindac moiety to form PSA sulfone and PSA sulfide, respectively. PSA was mono-hydroxylated and cleared more rapidly in mouse liver microsomes than in human liver microsomes. Of eight major human cytochrome P450s (CYPs), CYP3A4 and CYP2D6 exclusively catalyzed the hydroxylation and sulfoxidation reactions of PSA, respectively. We also examined the metabolism of PSA by three major human flavin monooxygenases (FMOs). FMO1, FMO3 and FMO5 were all capable of catalyzing the sulfoxidation (but not hydroxylation) of PSA, with FMO1 being by far the most active isoform. PSA was predominantly sulfoxidized in human kidney microsomes because FMO1 is the dominant isoform in human kidney. PSA (versus sulindac) is a preferred substrate of both CYPs and FMOs, likely because of its greater lipophilicity and masked-COOH group. Ketoconazole (a CYP3A4 inhibitor) and alkaline pH strongly inhibited the hydroxylation of PSA, but moderately suppressed its sulfoxidation in liver microsomes. Together, our results establish the metabolic pathways of PSA, identify the major enzymes mediating its biotransformations and reveal significant inter-species and inter-tissue differences in its metabolism.

  18. Inhibition of breast cancer cell motility with a non-cyclooxygenase inhibitory derivative of sulindac by suppressing TGFβ/miR-21 signaling.

    Science.gov (United States)

    Yi, Bin; Chang, Hong; Ma, Ruixia; Feng, Xiangling; Li, Wei; Piazza, Gary A; Xi, Yaguang

    2016-02-16

    Compelling efficacy on intervention of tumorigenesis by nonsteroidal anti-inflammatory drugs (NSAIDs) has been documented intensively. However, the toxicities related to cyclooxygenase (COX) inhibition resulting in suppression of physiologically important prostaglandins limit their clinical use for human cancer chemoprevention. A novel derivative of the NSAID sulindac sulfide (SS), referred as sulindac sulfide amide (SSA), was recently developed, which lacks COX inhibitory activity, yet shows greater suppressive effect than SS on growth of various cancer cells. In this study, we focus on the inhibitory activity of SSA on breast tumor cell motility, which has not been studied previously. Our results show that SSA treatment at non-cytotoxic concentrations can specifically reduce breast tumor cell motility without influencing tumor cell growth, and the mechanism of action involves the suppression of TGFβ signaling by directly blocking Smad2/3 phosphorylation. Moreover, miR-21, a well-documented oncogenic miRNA for promoting tumor cell metastasis, was also found to be involved in inhibitory activity of SSA in breast tumor cell motility through the modulation of TGFβ pathway. In conclusion, we demonstrate that a non-COX inhibitory derivative of sulindac can inhibit breast tumor metastasis by a mechanism involving the TGFβ/miR-21 signaling axis.

  19. Sulindac and Sulindac Metabolites in Nipple Aspirate Fluid and Effect on Drug Targets in a Phase I Trial

    OpenAIRE

    Thompson, Patricia A.; Hsu, Chiu-Hsieh; Green, Sylvan; Stopeck, Alison T.; Johnson, Karen; Alberts, David S.; Chow, H.-H. Sherry

    2010-01-01

    Regular use of nonsteroidal anti-inflammatory drugs (NSAIDs) has been associated with reduced risk of breast cancer. Sulindac, a non-selective NSAID with both cyclooxygenase 2 (COX2) dependent and independent activities, is a candidate for breast chemoprevention. We conducted a Phase Ib trial in 30 women at increased risk for breast cancer to evaluate the breast tissue distribution of sulindac at two dose levels (150 mg q.d. and 150 mg b.i.d. for 6 weeks), using nipple aspirate fluid (NAF) as...

  20. The Anti-Inflammatory Effects of Lipoxygenase and Cyclo-Oxygenase Inhibitors in Inflammation-Induced Human Fetal Glia Cells and the Aβ Degradation Capacity of Human Fetal Astrocytes in an Ex vivo Assay

    Directory of Open Access Journals (Sweden)

    Rea Pihlaja

    2017-05-01

    Full Text Available Chronic inflammation is a common phenomenon present in the background of multiple neurodegenerative diseases, including Alzheimer's disease (AD. The arachidonic acid pathway overproduces proinflammatory eicosanoids during these states and glial cells in the brain gradually lose their vital functions of protecting and supporting neurons. In this study, the role of different key enzymes of the eicosanoid pathway mediating inflammatory responses was examined in vitro and ex vivo using human fetal glial cells. Astrocytes and microglia were exposed to proinflammatory agents i.e., cytokines interleukin 1-β (IL-1β and tumor necrosis factor (TNF-α. ELISA assays were used to examine the effects of inhibitors of key enzymes in the eicosanoid pathway. Inhibitors for 5-lipoxygenase (5-LOX and cyclo-oxygenase 2 (COX-2 in both cell types and 5-, 12-, and 15-LOX-inhibitor in astrocytes reduced significantly IL-6 secretion, compared to exposed glial cells without inhibitors. The cytokine antibody array showed that especially treatments with 5, -12, and -15 LOX inhibitor in astrocytes, 5-LOX inhibitor in microglia and COX-2 inhibitor in both glial cell types significantly reduced the expression of multiple proinflammatory cytokines. Furthermore, human fetal astrocytes and microglia were cultured on top of AD-affected and control human brain sections for 30 h. According to the immunochemical evaluation of the level of total Aβ, astrocytes were very efficient at degrading Aβ from AD-affected brain sections ex vivo; simultaneously added enzyme inhibitors did not increase their Aβ degradation capabilities. Microglia were not able to reduce the level of total Aβ during the 30 h incubation time.

  1. Sulindac treatment in hereditary non-pollyposis colorectal cancer

    NARCIS (Netherlands)

    Rijcken, Fleur E. M.; Hollema, Harry; van der Zee, Ate G. J.; van der Sluis, Tineke; Ek, Wytske Boersma-van; Kleibeuker, Jan H.

    2007-01-01

    Non-steroidal anti-inflammatory drugs, e.g. sulindac have been extensively studied for chemoprevention in familial adenomatous polyposis, but not in hereditary non-polyposis colorectal cancer (HNPCC). We evaluated these effects in HNPCC using surrogate end-points for cancer risk. In a randomised dou

  2. Studies on the Metabolism and Biological Activity of the Epimers of Sulindac

    OpenAIRE

    Brunell, David; Sagher, Daphna; Kesaraju, Shailaja; Brot, Nathan; Weissbach, Herbert

    2011-01-01

    Sulindac is a nonsteroidal, anti-inflammatory drug (NSAID) that has also been studied for its anticancer activity. Recent studies suggest that sulindac and its metabolites act by sensitizing cancer cells to oxidizing agents and drugs that affect mitochondrial function, resulting in the production of reactive oxygen species and death by apoptosis. In contrast, normal cells are not killed under these conditions and, in some instances, are protected against oxidative stress. Sulindac has a methy...

  3. In Vivo Antineoplastic Effects of the NSAID Sulindac in an Oral Carcinogenesis Model.

    Science.gov (United States)

    Katoumas, Konstantinos; Nikitakis, Nikolaos; Perrea, Despina; Dontas, Ismene; Sklavounou, Alexandra

    2015-07-01

    The antineoplastic properties of the NSAID sulindac have long been studied. The purpose of this study was to explore sulindac's in vivo effects on oral squamous cell carcinoma (SCC) oncogenesis using the hamster cheek pouch oral carcinogenesis model (HOCM). Thirty Syrian golden hamsters were divided into three experimental and two control groups (n = 6 each). The animals' right buccal pouches were treated with carcinogen for 9 weeks in one experimental and one control group and for 14 weeks in all other three groups. The animals of two experimental groups received sulindac from the 1st week and those of the third experimental group from the 10th week. After the end of carcinogenesis, treated buccal pouches were removed and examined. In animals treated with carcinogen for 14 weeks, development of oral SCC and tumor volume were significantly lower in animals that received sulindac from the first week of the experiment. Oral SCC developing in animals that received sulindac were more frequently well differentiated compared with the control group. In animals treated with carcinogen for 9 weeks, the animals that received sulindac developed lower grade of epithelial dysplasia. Proliferation index Ki-67 and positivity for the antiapoptotic molecule survivin were lower in the animals that received sulindac. Treatment with sulindac appears to delays the progression of oral premalignant lesions to oral SCC in the HOCM, also resulting in smaller and better differentiated tumors. These in vivo antineoplastic effects may be related to sulindac's ability to decrease cell proliferation and to prevent survivin expression.

  4. The inhibition of Wnt/β-catenin signaling pathway in human colon cancer cells by sulindac.

    Science.gov (United States)

    Tai, Wei-Ping; Hu, Pin-Jin; Wu, Jing; Lin, Xiang-Chun

    2014-01-01

    The aberrant activation of Wnt/β-catenin signaling plays important roles in the initial development of colon cancer. Sulindac is a commonly used non-steroidal anti-inflammatory drug. We demonstrated the effects of sulindac on growth inhibition, apoptosis induction, and Wnt/β-catenin signaling suppression in human colon cancer cells. Sulindac significantly inhibited proliferation of HT-29 colon cancer cells in a dose- and time-dependent manner. Sulindac was found to induce the apoptosis of HT-29 cells and inhibit the Wnt/β-catenin pathway. The inhibition was further confirmed by the decreased protein levels of β-catenin. The results indicate that sulindac may play a beneficial role in the comprehensive treatment of colon cancer.

  5. Selenium and sulindac are synergistic to inhibit intestinal tumorigenesis in Apc/p21 mice

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    Bi Xiuli

    2013-01-01

    Full Text Available Abstract Background Both selenium and non-steroidal anti-inflammatory drug (NSAID sulindac are effective in cancer prevention, but their effects are affected by several factors including epigenetic alterations and gene expression. The current study was designed to determine the effects of the combination of selenium and sulindac on tumor inhibition and the underlying mechanisms. Results We fed the intestinal tumor model Apc/p21 mice with selenium- and sulindac-supplemented diet for 24 weeks, and found that the combination of selenium and sulindac significantly inhibited intestinal tumorigenesis, in terms of reducing tumor incidence by 52% and tumor multiplicities by 80% (p Conclusions The selenium is synergistic with sulindac to exert maximal effects on tumor inhibition. This finding provides an important chemopreventive strategy using combination of anti-cancer agents, which has a great impact on cancer prevention and has a promising translational potential.

  6. Molecular alterations associated with sulindac-resistant colon tumors in ApcMin/+ mice.

    Science.gov (United States)

    Greenspan, Emily J; Nichols, Frank C; Rosenberg, Daniel W

    2010-09-01

    Although nonsteroidal anti-inflammatory drugs (NSAID), including sulindac, have been used extensively as chemopreventive agents for colorectal cancer, results are not consistent. NSAIDs, most reportedly sulindac, often do not cause a complete regression of adenomas and some patients develop resistance to NSAID treatment. In this study, we evaluated the effect of sulindac on colon tumorigenesis in the Apc(Min/+) mouse model. Sulindac (180 ppm) given in drinking water for 9 weeks to Apc(Min/+) mice significantly reduced the size of colon tumors, but actually caused an increase in colon tumor multiplicity relative to untreated controls (average of 5.5 versus 1.6 tumors per mouse, respectively; P sulindac significantly reduced tumor size and multiplicity relative to untreated controls (average of 2.3 versus 42.0 tumors per mouse, respectively; P sulindac treatment. Sulindac is also known to exert its growth inhibitory effects through regulation of many noncyclooxygenase targets, including p21, beta-catenin, E-cadherin, mitochondrial apoptotic proteins, and peroxisome proliferator-activated receptor-gamma. We found that sulindac treatment protected against E-cadherin loss in colon tumors, with associated inhibition of nuclear beta-catenin accumulation. Importantly, p21(WAF1/cip1) and peroxisome proliferator-activated receptor-gamma expression were absent in colon tumors from sulindac-treated mice, suggesting that loss of these proteins is necessary for drug resistance. Together, these observations may be translatable to designing novel clinical therapies using combinations of agents that target multiple molecular pathways to overcome sulindac resistance.

  7. Dietary anthocyanin-rich tart cherry extract inhibits intestinal tumorigenesis in APC(Min) mice fed suboptimal levels of sulindac.

    Science.gov (United States)

    Bobe, Gerd; Wang, Bing; Seeram, Navindra P; Nair, Muraleedharan G; Bourquin, Leslie D

    2006-12-13

    A promising approach for cancer chemoprevention might be a combination therapy utilizing dietary phytochemicals and anticarcinogenic pharmaceuticals at a suboptimal dosage to minimize any potential adverse side effects. To test this hypothesis, various dosages of anthocyanin-rich tart cherry extract were fed in combination with suboptimal levels of the nonsteroidal anti-inflammatory drug sulindac to APCMin mice for 19 weeks. By the end of the feeding period, fewer mice that were fed the anthocyanin-rich extract in combination with sulindac lost more than 10% of body weight than mice fed sulindac alone. Mice that were fed anthocyanin-rich extract (at any dose) in combination with sulindac had fewer tumors and a smaller total tumor burden (total tumor area per mouse) in the small intestine when compared to mice fed sulindac alone. These results suggest that a dietary combination of tart cherry anthocyanins and sulindac is more protective against colon cancer than sulindac alone.

  8. Sulindac Induces Apoptosis and Inhibits Tumor Growth In Vivo in Head and Neck Squamous Cell Carcinoma

    Directory of Open Access Journals (Sweden)

    Mark A. Scheper

    2007-03-01

    Full Text Available Sulindac has antineoplastic effects on various cancer cell lines; consequently, we assessed sulindac's effects on laryngeal squamous cell carcinoma (SCC cells in vitro and in vivo. In vitro, SCC (HEP-2 cells treated with various cyclooxygenase inhibitors or transfected with constitutively active signal transducer and activator of transcription 3 (Stat3 or survivin vectors were analyzed using Western blot analysis, annexin V assay, and cell proliferation assay. In parallel, nude mice injected subcutaneously with HEP-2 cells were either treated intraperitoneally with sulindac or left untreated, and analyzed for tumor weight, survivin expression, and tyrosine-phosphorylated Stat3 expression. In vitro studies confirmed the selective antiproliferative and proapoptotic effects of sulindac, which also downregulated Stat3 and survivin protein expression. Stat3 or survivin forced expression partially rescued the antiproliferative effects of sulindac. In vivo studies showed significant repression of HEP-2 xenograft growth in sulindactreated mice versus controls, with near-complete resolution at 10 days. Additionally, tumor specimens treated with sulindac showed downregulation of phosphorylated tyrosine-705 Stat3 and survivin expression. Taken together, our data suggest, for the first time, a specific inhibitory effect of sulindac on tumor growth and survivin expression in laryngeal cancer, both in vitro and in vivo, in a Stat3-dependent manner, suggesting a novel therapeutic approach to head and neck cancer.

  9. Combination of sulindac and dichloroacetate kills cancer cells via oxidative damage.

    Science.gov (United States)

    Ayyanathan, Kasirajan; Kesaraju, Shailaja; Dawson-Scully, Ken; Weissbach, Herbert

    2012-01-01

    Sulindac is an FDA-approved non-steroidal anti-inflammatory drug with documented anticancer activities. Our recent studies showed that sulindac selectively enhanced the killing of cancer cells exposed to oxidizing agents via production of reactive oxygen species (ROS) resulting in mitochondrial dysfunction. This effect of sulindac and oxidative stress on cancer cells could be related to the defect in respiration in cancer cells, first described by Warburg 50 years ago, known as the Warburg effect. We postulated that sulindac might enhance the selective killing of cancer cells when combined with any compound that alters mitochondrial respiration. To test this hypothesis we have used dichloroacetate (DCA), which is known to shift pyruvate metabolism away from lactic acid formation to respiration. One might expect that DCA, since it stimulates aerobic metabolism, could stress mitochondrial respiration in cancer cells, which would result in enhanced killing in the presence of sulindac. In this study, we have shown that the combination of sulindac and DCA enhances the selective killing of A549 and SCC25 cancer cells under the conditions used. As predicted, the mechanism of killing involves ROS production, mitochondrial dysfunction, JNK signaling and death by apoptosis. Our results suggest that the sulindac-DCA drug combination may provide an effective cancer therapy.

  10. Combination of sulindac and dichloroacetate kills cancer cells via oxidative damage.

    Directory of Open Access Journals (Sweden)

    Kasirajan Ayyanathan

    Full Text Available Sulindac is an FDA-approved non-steroidal anti-inflammatory drug with documented anticancer activities. Our recent studies showed that sulindac selectively enhanced the killing of cancer cells exposed to oxidizing agents via production of reactive oxygen species (ROS resulting in mitochondrial dysfunction. This effect of sulindac and oxidative stress on cancer cells could be related to the defect in respiration in cancer cells, first described by Warburg 50 years ago, known as the Warburg effect. We postulated that sulindac might enhance the selective killing of cancer cells when combined with any compound that alters mitochondrial respiration. To test this hypothesis we have used dichloroacetate (DCA, which is known to shift pyruvate metabolism away from lactic acid formation to respiration. One might expect that DCA, since it stimulates aerobic metabolism, could stress mitochondrial respiration in cancer cells, which would result in enhanced killing in the presence of sulindac. In this study, we have shown that the combination of sulindac and DCA enhances the selective killing of A549 and SCC25 cancer cells under the conditions used. As predicted, the mechanism of killing involves ROS production, mitochondrial dysfunction, JNK signaling and death by apoptosis. Our results suggest that the sulindac-DCA drug combination may provide an effective cancer therapy.

  11. Renal hemodynamic effects of nabumetone, sulindac, and placebo in patients with osteoarthritis.

    Science.gov (United States)

    Cangiano, J L; Figueroa, J; Palmer, R

    1999-03-01

    We assessed the effects of nabumetone, sulindac, and placebo on renal function and renal excretion of vasodilatory prostaglandins in older female patients (age >50 years) with osteoarthritis and normal renal function. Using a prospective, crossover design, we compared the effects of nabumetone 2000 mg/d and sulindac 400 mg/d with placebo on glomerular filtration rate (GFR), renal plasma flow (RPF), and urinary excretion of prostaglandin E2 and 6-keto-prostaglandin F1alpha in 12 patients. Urinary excretion of vasodilatory prostaglandins was not decreased after 14 days of treatment with either nabumetone or sulindac. Likewise, treatment with nabumetone or sulindac did not significantly alter renal function compared with placebo. There were no differences in mean changes in GFR or RPF from baseline after treatment with nabumetone or sulindac compared with placebo. The mean (+/- SD) changes in GFR from baseline were 0%+/-8% in patients receiving nabumetone, -8%+/-15% in patients receiving sulindac, and -7%+/-15% in patients receiving placebo. The results of this study demonstrate that treatment with nabumetone or sulindac caused no deterioration in renal function in older female patients with osteoarthritis and normal renal function.

  12. Acute kidney injury, hyperbilirubinemia, and ischemic skin necrosis due to massive sulindac overdose.

    Science.gov (United States)

    Vaughn, John L; Shah, Kejal V; Ghossein, Maroun M; Meyer, William L; Kirkpatrick, Robert B

    2015-01-01

    Sulindac is a long-acting nonsteroidal anti-inflammatory drug (NSAID) widely used for the management of osteoarthritis, rheumatoid arthritis, ankylosing sponydlitis, and acute gouty arthritis. Reports of sulindac toxicity in the literature are rare. We report the case of a 22-year old male with a history of bipolar disorder who was brought to the emergency department after ingesting approximately 15 g of sulindac in a suicide attempt. He was found to have acute kidney injury and hyperbilirubinemia. Despite aggressive fluid resuscitation, his renal function progressively worsened requiring the initiation of hemodialysis. Ten days following ingestion of sulindac, he began to develop ischemic skin changes with a gangrenous appearance in his hands and feet. He continued to receive supportive treatment, and his acute kidney injury, hyperbillirubinemia, and ischemic skin necrosis eventually resolved. Clinicians should be aware of this long-acting NSAID and its ability to cause prolonged multisystem organ dysfunction.

  13. Exploring the mechanism of interaction between sulindac and human serum albumin: Spectroscopic and molecular modeling methods

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiao-Ping; Hou, Ya-He [Department of Material Engineering, Xuzhou College of Industrial Technology, Xuzhou, Jiangsu 221140 (China); Wang, Li [Department of Chemistry, College of Chemistry and Environmental Engineering, Yangtze University, Jingzhou, Hubei 434023 (China); Zhang, Ye-Zhong, E-mail: zhangfluorescence@126.com [Department of Chemistry, College of Chemistry and Environmental Engineering, Yangtze University, Jingzhou, Hubei 434023 (China); Liu, Yi, E-mail: prof.liuyi@263.net [Department of Chemistry, College of Chemistry and Environmental Engineering, Yangtze University, Jingzhou, Hubei 434023 (China); College of Chemistry and Molecular Sciences and State Key Laboratory of Virology, Wuhan University, Wuhan 430072 (China)

    2013-06-15

    In the present study, a combination of fluorescence, molecular modeling and circular dichroism (CD) approaches had been employed to investigate the interaction between sulindac and human serum albumin (HSA). Results of mechanism discussion demonstrated that the fluorescence quenching of HSA by sulindac was a static quenching procedure. Binding parameters calculated from the modified Stern–Volmer equation showed that sulindac bound to HSA with the binding affinities in the order of 10{sup 5} L mol{sup −1}. The thermodynamic parameters (ΔH=−18.58 kJ mol{sup −1}; ΔS=37.26 J mol{sup −1} K{sup −1}) obtained by the van′t Hoff equation revealed that hydrophobic forces played a leading role in the formation of sulindac–HSA complex, but hydrogen bonds could not be omitted. Site marker competitive experiments revealed a displacement of warfarin by sulindac, which indicated that the binding site of sulindac to HSA located in the sub-domain IIA (Sudlow′s site I). The molecular docking study confirmed the specific binding mode and binding site obtained by fluorescence and site marker competitive experiments. CD and three-dimensional fluorescence spectroscopy were used to investigate the changes of HSA secondary structure and microenvironment in the presence of sulindac. Alterations of HSA conformation were observed with the reduction of α-helix from 60.1% (free HSA) to 57.3%, manifesting a slight unfolding of the polypeptides of protein. -- Highlights: ► The quenching mechanism between sulindac and HSA is a static process. ► The binding of sulindac to HSA takes place in sub-domain IIA (Sudlow′s site I). ► The binding is spontaneous and hydrophobic force plays major role in stabilizing the complex. ► CD and 3-D fluorescence spectra prove the change of the microenvironment and conformation of HSA.

  14. Target delivery and controlled release of the chemopreventive drug sulindac by using an advanced layered double hydroxide nanomatrix formulation system.

    Science.gov (United States)

    Minagawa, Keiji; Berber, Mohamed R; Hafez, Inas H; Mori, Takeshi; Tanaka, Masami

    2012-04-01

    Target delivery and controlled release of the chemopreventive drug sulindac that possesses low water solubility present a great challenge for its pharmaceutical industry. Here, we offered an advanced nanomatrix formulation system of sulindac based on layered double hydroxide materials. The X-ray analysis and infrared spectroscopy confirmed the incorporation of sulindac into the gallery of the layered double hydroxides. The incorporation ratios of sulindac were recorded to be 45, 31 and 20 for coprecipitation, anion-exchange and reconstruction techniques, respectively. The scanning electron microscopy showed a nanomatrix-structure of ~50 nm. The release studies of sulindac-nanomatrix showed a 96% controlled release at the small intestine solution during 3 h(s), indicating an enhancement in the dissolution profile of sulindac after the matrix formation. The layered structure of the matrix supplied sulindac with a well-ordered structure and a relatively hydrophobic microenvironment that controlled the guest hydrolysis and reactivity during the release process. The laminar structure of layered double hydroxides offered a safe preservation for sulindac against photodecarboxylation, and enhanced the drug thermal stability from 190 to 230° C. The ionic electrostatic interaction of sulindac through its acidic group with layered double hydroxides demolished the gastrointestinal ulceration.

  15. Sulindac has strong antifibrotic effects by suppressing STAT3-related miR-21.

    Science.gov (United States)

    Zhou, Xue; Li, You-Jie; Gao, Shu-Yan; Wang, Xiao-Zhi; Wang, Ping-Yu; Yan, Yun-Fei; Xie, Shu-Yang; Lv, Chang-Jun

    2015-05-01

    Pulmonary fibrosis (PF) is a disease with an unknown cause and a poor prognosis. In this study, we aimed to explore the pathogenesis of PF and the mechanism of sulindac in attenuating bleomycin (BLM)-induced PF. The rat PF model was induced by BLM and verified through histological studies and hydroxyproline assay. The severity of BLM-induced PF in rats and other effects, such as the extent of the wet lung to bw ratios, thickening of alveolar interval or collagen deposition, was obviously ameliorated in sulindac-treated rat lungs compared with BLM-induced lungs. Sulindac also reversed the epithelial mesenchymal transition (EMT) and inhibited the PF process by restoring the levels of E-cadherin and α-smooth muscle actin (SMA) in A549 cells. Our results further demonstrated that the above effects of sulindac might be related to regulating of interferon gamma (IFN-γ) expression, which further affects signal transducers and activators of transcription 3 (STAT3) and phosphorylated STAT3 (p-STAT3) levels. Moreover, higher miR-21 levels with the decreased E-cadherin and increased α-SMA expressions were found in transforming growth factor-β1-treated A549 cells, which can be reversed by sulindac. Collectively, our results demonstrate that by decreasing IFN-γ-induced STAT3/p-STAT3 expression to down-regulate miR-21, sulindac could significantly reverse EMT in A549 cells and prevent BLM-induced PF.

  16. Evaluating the inhibitory potential of sulindac against the bleomycin-induced pulmonary fibrosis in wistar rats.

    Science.gov (United States)

    Verma, Ramesh; Brahmankar, Mahesh; Kushwah, Lokendra; Suresh, Balakrishnan

    2013-11-01

    The present study examined the protective effect of sulindac on bleomycin-induced lung fibrosis in rats. Animals were divided into saline group, bleomycin group (single intra-tracheal instillation of bleomycin) and bleomycin+sulindac (orally from day 1 to day 20). Bleomycin administration reduced the body weight, altered antioxidant status (such as superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and glutathione) while it increased the lung weight, hydroxyproline content, collagen deposition and lipid peroxidation. However, simultaneous administration of sulindac improved the body weight, antioxidant status and decreased the collagen deposition in lungs. Moreover, the levels of inflammatory cytokine tumour necrosis factor-α increased in bleomycin-induced group, whereas, on treatment with sulindac the levels of tumour necrosis factor-α were found reduced. Finally, histological evidence also supported the ability of sulindac to inhibit bleomycin-induced lung fibrosis. The results of the present study indicate that sulindac can be used as an agent against bleomycin-induced pulmonary fibrosis.

  17. Pharmacological protection of retinal pigmented epithelial cells by sulindac involves PPAR-α.

    Science.gov (United States)

    Sur, Arunodoy; Kesaraju, Shailaja; Prentice, Howard; Ayyanathan, Kasirajan; Baronas-Lowell, Diane; Zhu, Danhong; Hinton, David R; Blanks, Janet; Weissbach, Herbert

    2014-11-25

    The retinal pigmented epithelial (RPE) layer is one of the major ocular tissues affected by oxidative stress and is known to play an important role in the etiology of age-related macular degeneration (AMD), the major cause of blinding in the elderly. In the present study, sulindac, a nonsteroidal antiinflammatory drug (NSAID), was tested for protection against oxidative stress-induced damage in an established RPE cell line (ARPE-19). Besides its established antiinflammatory activity, sulindac has previously been shown to protect cardiac tissue against ischemia/reperfusion damage, although the exact mechanism was not elucidated. As shown here, sulindac can also protect RPE cells from chemical oxidative damage or UV light by initiating a protective mechanism similar to what is observed in ischemic preconditioning (IPC) response. The mechanism of protection appears to be triggered by reactive oxygen species (ROS) and involves known IPC signaling components such as PKG and PKC epsilon in addition to the mitochondrial ATP-sensitive K(+) channel. Sulindac induced iNOS and Hsp70, late-phase IPC markers in the RPE cells. A unique feature of the sulindac protective response is that it involves activation of the peroxisome proliferator-activated receptor alpha (PPAR-α). We have also used low-passage human fetal RPE and polarized primary fetal RPE cells to validate the basic observation that sulindac can protect retinal cells against oxidative stress. These findings indicate a mechanism for preventing oxidative stress in RPE cells and suggest that sulindac could be used therapeutically for slowing the progression of AMD.

  18. Sulindac, a non-steroidal anti-inflammatory drug, mediates breast cancer inhibition as an immune modulator.

    Science.gov (United States)

    Yin, Tao; Wang, Guoping; Ye, Tinghong; Wang, Yongsheng

    2016-01-18

    The cooperation of adaptive immunity with pharmacologic therapy influences cancer progression. Though non-steroidal anti-inflammatory drugs (NSAIDs) have a long history of cancer prevention, it is unclear whether adaptive immune system affects the action of those drugs. In present study, we revealed a novel immunological mechanism of sulindac. Our data showed that sulindac had substantial efficacy as a single agent against 4T1 murine breast cancer and prolonged the survival of tumor-bearing mice. However, in the athymic nude mice, sulindac treatment was ineffective. Further in vivo T cell subsets depletion experiments showed that CD8+ T lymphocytes deficiency reversed the anti-tumor effect of sulindac. In addition, sulindac significantly reduced M2 macrophages recruitment, cancer-related inflammation and tumor angiogenesis. Our results advance our understanding of the mechanisms of NSAIDs, and more importantly, this will provide insight into rational drug design or antitumor immunotherapy.

  19. Sulindac enhances the killing of cancer cells exposed to oxidative stress.

    Directory of Open Access Journals (Sweden)

    Maria Marchetti

    Full Text Available BACKGROUND: Sulindac is an FDA-approved non-steroidal anti-inflammatory drug (NSAID that affects prostaglandin production by inhibiting cyclooxygenases (COX 1 and 2. Sulindac has also been of interest for more than decade as a chemopreventive for adenomatous colorectal polyps and colon cancer. PRINCIPAL FINDINGS: Pretreatment of human colon and lung cancer cells with sulindac enhances killing by an oxidizing agent such as tert-butyl hydroperoxide (TBHP or hydrogen peroxide. This effect does not involve cyclooxygenase (COX inhibition. However, under the conditions used, there is a significant increase in reactive oxygen species (ROS within the cancer cells and a loss of mitochondrial membrane potential, suggesting that cell death is due to apoptosis, which was confirmed by Tunel assay. In contrast, this enhanced killing was not observed with normal lung or colon cells. SIGNIFICANCE: These results indicate that normal and cancer cells handle oxidative stress in different ways and sulindac can enhance this difference. The combination of sulindac and an oxidizing agent could have therapeutic value.

  20. Sulindac reversal of 15-PGDH-mediated resistance to colon tumor chemoprevention with NSAIDs.

    Science.gov (United States)

    Fink, Stephen P; Dawson, Dawn M; Zhang, Yongyou; Kresak, Adam; Lawrence, Earl G; Yang, Peiying; Chen, Yanwen; Barnholtz-Sloan, Jill S; Willis, Joseph E; Kopelovich, Levy; Markowitz, Sanford D

    2015-02-01

    Non-steroidal anti-inflammatory drugs prevent colorectal cancer by inhibiting cyclooxygenase (COX) enzymes that synthesize tumor-promoting prostaglandins. 15-hydroxyprostaglandin dehydrogenase (15-PGDH) is a tumor suppressor that degrades tumor-promoting prostaglandins. Murine knockout of 15-PGDH increases susceptibility to azoxymethane-induced colon tumors. It also renders these mice resistant to celecoxib, a selective inhibitor of inducible COX-2 during colon neoplasia. Similarly, humans with low colonic 15-PGDH are also resistant to colon adenoma prevention with celecoxib. Here, we used aspirin and sulindac, which inhibit both COX-1 and COX-2, in order to determine if these broader COX inhibitors can prevent colon tumors in 15-PGDH knockout (KO) mice. Unlike celecoxib, sulindac proved highly effective in colon tumor prevention of 15-PGDH KO mice. Significantly, however, aspirin demonstrated no effect on colon tumor incidence in either 15-PGDH wild-type or KO mice, despite a comparable reduction in colonic mucosal Prostaglandin E₂ (PGE₂) levels by both sulindac and aspirin. Notably, colon tumor prevention activity by sulindac was accompanied by a marked induction of lymphoid aggregates and proximal colonic inflammatory mass lesions, a side effect seen to a lesser degree with celecoxib, but not with aspirin. These findings suggest that sulindac may be the most effective agent for colon cancer prevention in humans with low 15-PGDH, but its use may also be associated with inflammatory lesions in the colon.

  1. Phospho-sulindac (OXT-328) combined with difluoromethylornithine prevents colon cancer in mice.

    Science.gov (United States)

    Mackenzie, Gerardo G; Ouyang, Nengtai; Xie, Gang; Vrankova, Kvetoslava; Huang, Liqun; Sun, Yu; Komninou, Despina; Kopelovich, Levy; Rigas, Basil

    2011-07-01

    The nonsteroidal anti-inflammatory drug (NSAID) sulindac and the ornithine decarboxylase (ODC) antagonist difluoromethylornithine (DFMO), individually and together, are effective inhibitors of colon carcinogenesis. However, chronic use of sulindac is associated with significant side effects. We evaluated the chemopreventive efficacy of phospho-sulindac (P-S, OXT-328), an apparently safe derivative of sulindac, together with DFMO, in HT-29 human colon cancer xenografts. Nude mice were divided into four groups as follows: group 1 received vehicle (corn oil); group 2 received P-S (100 mg/kg/d) by oral gavage; group 3 received DFMO (2% in drinking water); and group 4 received P-S (100 mg/kg/d) by gavage plus DFMO (2% in drinking water; P-S/DFMO). Eighteen days after implantation, compared with controls, tumor volume was inhibited 65.9% by P-S, 52.9% by DFMO, and 70.9% by P-S/DFMO (P sulindac. P-S/DFMO has an intricate mechanism of action extending beyond polyamines and including the thioredoxin system, an emerging regulator of chemoprevention. P-S/DFMO merits further evaluation.

  2. Crystallization of micro particles of sulindac using rapid expansion of supercritical solution

    Science.gov (United States)

    Zeinolabedini Hezave, Ali; Esmaeilzadeh, Feridun

    2010-11-01

    In pharmaceutical industry, many drugs exhibit poor solubility in biological fluid. Solubility of drugs affects on the rate of dissolution and bioavailability in biological fluids. The bioavailability of drugs can be enhanced by decreasing the drug particle size. In this study, sulindac was micronized via rapid expansion of supercritical solution (RESS) where CO2 was used as a solvent. The experiments were conducted to investigate the effect of the extraction pressure and temperature (140-230 bar and 40-60 °C), collection distance (1-10 cm), effective nozzle diameter (450-1700 μm) and nozzle length (2-15 mm) on the size and morphology of the sulindac particles. The size and morphology of the precipitated particles were monitored by scanning electron microscopy (SEM). The particle size of intact sulindac particles was about 33.03 μm, while the average particle size of the micronized sulindac particles was between 0.76 and 8.02 μm based on different experimental conditions. Additionally, the different morphology of the micronized particles was observed like needle, rectangular, quasi spherical and irregular form while the morphology of the intact particles of sulindac was rectangular and irregular.

  3. Sulindac-derived RXRα modulators inhibit cancer cell growth by binding to a novel site.

    Science.gov (United States)

    Chen, Liqun; Wang, Zhi-Gang; Aleshin, Alexander E; Chen, Fan; Chen, Jiebo; Jiang, Fuquan; Alitongbieke, Gulimiran; Zeng, Zhiping; Ma, Yue; Huang, Mingfeng; Zhou, Hu; Cadwell, Gregory; Zheng, Jian-Feng; Huang, Pei-Qiang; Liddington, Robert C; Zhang, Xiao-kun; Su, Ying

    2014-05-22

    Retinoid X receptor-alpha (RXRα), an intriguing and unique drug target, can serve as an intracellular target mediating the anticancer effects of certain nonsteroidal anti-inflammatory drugs (NSAIDs), including sulindac. We report the synthesis and characterization of two sulindac analogs, K-8008 and K-8012, which exert improved anticancer activities over sulindac in a RXRα-dependent manner. The analogs inhibit the interaction of the N-terminally truncated RXRα (tRXRα) with the p85α subunit of PI3K, leading to suppression of AKT activation and induction of apoptosis. Crystal structures of the RXRα ligand-binding domain (LBD) with K-8008 or K-8012 reveal that both compounds bind to tetrameric RXRα LBD at a site different from the classical ligand-binding pocket. Thus, these results identify K-8008 and K-8012 as tRXRα modulators and define a binding mechanism for regulating the nongenomic action of tRXRα.

  4. NSAID sulindac and its analog bind RXRalpha and inhibit RXRalpha-dependent AKT signaling.

    Science.gov (United States)

    Zhou, Hu; Liu, Wen; Su, Ying; Wei, Zhen; Liu, Jie; Kolluri, Siva Kumar; Wu, Hua; Cao, Yu; Chen, Jiebo; Wu, Yin; Yan, Tingdong; Cao, Xihua; Gao, Weiwei; Molotkov, Andrei; Jiang, Fuquan; Li, Wen-Gang; Lin, Bingzhen; Zhang, Hai-Ping; Yu, Jinghua; Luo, Shi-Peng; Zeng, Jin-Zhang; Duester, Gregg; Huang, Pei-Qiang; Zhang, Xiao-Kun

    2010-06-15

    Nonsteroidal anti-inflammatory drugs (NSAIDs) exert their anticancer effects through cyclooxygenase-2 (COX-2)-dependent and independent mechanisms. Here, we report that Sulindac, an NSAID, induces apoptosis by binding to retinoid X receptor-alpha (RXRalpha). We identified an N-terminally truncated RXRalpha (tRXRalpha) in several cancer cell lines and primary tumors, which interacted with the p85alpha subunit of phosphatidylinositol-3-OH kinase (PI3K). Tumor necrosis factor-alpha (TNFalpha) promoted tRXRalpha interaction with the p85alpha, activating PI3K/AKT signaling. When combined with TNFalpha, Sulindac inhibited TNFalpha-induced tRXRalpha/p85alpha interaction, leading to activation of the death receptor-mediated apoptotic pathway. We designed and synthesized a Sulindac analog K-80003, which has increased affinity to RXRalpha but lacks COX inhibitory activity. K-80003 displayed enhanced efficacy in inhibiting tRXRalpha-dependent AKT activation and tRXRalpha tumor growth in animals.

  5. Synthesis and biological evaluation of nitric oxide-donating analogues of sulindac for prostate cancer treatment.

    Science.gov (United States)

    Nortcliffe, Andrew; Ekstrom, Alexander G; Black, James R; Ross, James A; Habib, Fouad K; Botting, Nigel P; O'Hagan, David

    2014-01-15

    A series of analogues of the non-steroidal anti-inflammatory drug (NSAID) sulindac 1 were synthesised tethered to nitric oxide (NO) donating functional groups. Sulindac shows antiproliterative effects against immortal PC3 cell lines. It was previously demonstrated that the effect can be enhanced when tethered to NO releasing groups such as nitrate esters, furoxans and sydnonimines. To explore this approach further, a total of fifty-six sulindac-NO analogues were prepared and they were evaluated as NO-releasing cytotoxic agents against prostate cancer (PCa) cell lines. Compounds 1k and 1n exhibited significant cytotoxic with IC50 values of 6.1±4.1 and 12.1±3.2μM, respectively, coupled with observed nitric oxide release.

  6. Preparation and characterization of a sulindac sensor based on PVC/TOA-SUL membrane.

    Science.gov (United States)

    Lenik, Joanna

    2014-04-01

    A potentiometric sulindac sensitive sensor based on tetraoctylammonium (Z)-5-fluoro-2-methyl-1-[[p-(methylsulfinyl)phenyl]methylene]-1H-indene-3-acetate (TOA-SUL) was described. The electrode responded with sensitivity of 57.5±1.6mV decade(-1) over the linear range 5×10(-5)-1×10(-2)mol L(-1) at pH6.0-9.0. It had the limit of detection 1.4×10(-5)mol L(-1), a fast response time of 13s and showed clear discrimination of sulindac ions from several inorganic and organic compounds and also amino acids. This electrode did not contain any inner solutions, so it was easy and comfortable to use. The proposed sensor was used to determine sulindac in clear solution and in urine sample solution.

  7. Apoptosis of human gastric cancer SGC-7901 cells induced by mitomycin combined with sulindac

    Institute of Scientific and Technical Information of China (English)

    Li Ma; Yong-Le Xie; Yi Yu; Qiu-Ning Zhang

    2005-01-01

    AIM: To investigate the effects of mitomycin (MMC)combined with sulindac on cell viability, apoptotic induction and expression of apoptosis-related gene Bcl-2 and cyclooxygenase-2 (COX-2)in gastric cancer SGC-7901cells.METHODS: Human gastric cancer SGC-7901 cells were divided into three treatment groups,namely sulindac treatment group, MMC treatment group and combined sulindac with MMC treatment group. After being treated with drugs, cell viability was examined by MTr assay.Flow cytometry was used to evaluate the cell cycle distribution and apoptotic rates. Morphology of the cells was observed under light microscope and interactive laser microscope. Expression of COX-2 and Bcl-2 was determined by immunocytochemical method.RESULTS: After exposure for 12 h to three kinds of drugs,gastric cancer SGC-7901 cells presented some morphological features of apoptosis, including cell shrinkage, nuclear condensation, DNA fragmentation and formation of apoptotic bodies. Growth inhibition was more obvious in combined sulindac with MMC treatment group and sulindac treatment group than in MMC treatment group. The apoptotic rates in co-treated cells and MMC-treated cells 24 h after treatment were 12.0% and 7.2%, respectively.After exposure for 24 h to MMC, the expression of COX-2and Bcl-2 protein was up-regulated, COX-2 levels were down-regulated but Bcl-2 gene expression was not changed significantly in combined treatment group.CONCLUSION: MMC-induced apoptosis is reduced by up-regulating the expression of COX-2 and Bcl-2 genes.MMC combined with sulindac can suppress the growth of gastric cancer cells through induction of apoptosis mediated by down-regulation of apoptosis-related Bcl-2and COX-2 gene.

  8. CXCR2 inhibition enhances sulindac-mediated suppression of colon cancer development.

    Science.gov (United States)

    Lee, Yong Suk; Choi, Dongwon; Kim, Nam Yoon; Yang, Sara; Jung, Eunson; Hong, Mingu; Yang, Dongyun; Lenz, Heinz-Josef; Hong, Young-Kwon

    2014-07-01

    Small chemical compound sulindac has been approved as a preventive approach against colon cancer for its effectiveness in treatment of precancerous adenoma. Due to its severe toxicities in the cardiovascular, gastrointestinal and renal systems, however, a combination of low-dose sulindac with other chemopreventive agents has been sought after as an alternative therapeutic strategy that could increase its effectiveness, while minimizing its adverse effects. To identify the promising alternative approach, we investigated the therapeutic potential of targeting the interleukin (IL)-8/CXCR2 pathway in colon cancer treatment using both loss-of-function (CXCR2 knockout) and gain-of-function (IL-8 overexpression) mouse models, as the IL-8/CXCR2 pathway has been shown to be activated in intestinal tumors of both human and experimental animals. We found that deletion of CXCR2 gene and ectopic expression of IL-8 suppresses and enhances, respectively, intestinal tumor development caused by a mutation in the APC gene. Moreover, a single copy deletion of CXCR2 gene resulted in abrogation of COX-2 and Gro-α upregulation in intestinal tumors caused by the APC mutation. Moreover, a single copy (heterozygote) deletion of CXCR2 gene was sufficient to synergize with a low-dose sulindac treatment in suppressing APCmin-induced intestinal polyposis. Together, our study provides a therapeutic justification of combined inhibition of CXCR2 and sulindac treatment in colon cancer prevention.

  9. Sulindac modulates secreted protein expression from LIM1215 colon carcinoma cells prior to apoptosis.

    Science.gov (United States)

    Greening, David W; Ji, Hong; Kapp, Eugene A; Simpson, Richard J

    2013-11-01

    Colorectal cancer (CRC) is a major cause of mortality in Western populations. Growing evidence from human and rodent studies indicate that nonsteroidal anti-inflammatory drugs (NSAIDs) cause regression of existing colon tumors and act as effective chemopreventive agents in sporadic colon tumor formation. Although much is known about the action of the NSAID sulindac, especially its role in inducing apoptosis, mechanisms underlying these effects is poorly understood. In previous secretome-based proteomic studies using 2D-DIGE/MS and cytokine arrays we identified over 150 proteins released from the CRC cell line LIM1215 whose expression levels were dysregulated by treatment with 1mM sulindac over 16h; many of these proteins are implicated in molecular and cellular functions such as cell proliferation, differentiation, adhesion, angiogenesis and apoptosis (Ji et al., Proteomics Clin. Appl. 2009, 3, 433-451). We have extended these studies and describe here an improved protein/peptide separation strategy that facilitated the identification of 987 proteins and peptides released from LIM1215 cells following 1mM sulindac treatment for 8h preceding the onset of apoptosis. This peptidome separation strategy involved fractional centrifugal ultrafiltration of concentrated cell culture media (CM) using nominal molecular weight membrane filters (NMWL 30K, 3K and 1K). Proteins isolated in the >30K and 3-30K fractions were electrophoretically separated by SDS-PAGE and endogenous peptides in the 1-3K membrane filter were fractioned by RP-HPLC; isolated proteins and peptides were identified by nanoLC-MS-MS. Collectively, our data show that LIM1215 cells treated with 1mM sulindac for 8h secrete decreased levels of proteins associated with extracellular matrix remodeling (e.g., collagens, perlecan, syndecans, filamins, dyneins, metalloproteinases and endopeptidases), cell adhesion (e.g., cadherins, integrins, laminins) and mucosal maintenance (e.g., glycoprotein 340 and mucins 5AC, 6

  10. Nitric oxide-releasing sulindac is a novel skin cancer chemopreventive agent for UVB-induced photocarcinogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Chaudhary, Sandeep C.; Singh, Tripti; Kapur, Puneet; Weng, Zhiping; Arumugam, Aadithya; Elmets, Craig A. [Department of Dermatology, University of Alabama at Birmingham, 1530 3rd Avenue South, VH509, Birmingham, AL 35294-0019 (United States); Kopelovich, Levy [Division of Cancer Prevention, National Cancer Institute, 6130 Executive Blvd, Suite 2114, Bethesda, MD 20892 (United States); Athar, Mohammad, E-mail: mathar@uab.edu [Department of Dermatology, University of Alabama at Birmingham, 1530 3rd Avenue South, VH509, Birmingham, AL 35294-0019 (United States)

    2013-05-01

    Nitric oxide (NO)-releasing non-steroidal anti-inflammatory drugs (NO-NSAIDs) which have been synthesized to reduce gastro-intestinal and cardiovascular toxicities of NSAIDs, possess anti-proliferative, pro-apoptotic and anti-cancer activities. Here, we show that NO-sulindac inhibited UVB-induced skin tumorigenesis in SKH-1 hairless mice. Topical application of NO-sulindac reduced tumor incidence, number (p < 0.05) and volume (p < 0.005) as compared to UVB (alone)-irradiated vehicle-treated mice. An increase in TUNEL-positive cells in skin lesions was accompanied by the enhanced Bax:Bcl-2 ratio. The expression of pro-apoptotic Bax was increased whereas anti-apoptotic Bcl-2 reduced. However, proliferation was identified as the major target of NO-sulindac in this study. A reduced expression of PCNA and cyclin D1 associated with the dampening of cell cycle progression was observed. The mechanism of this inhibition was related to the reduction in UVB-induced Notch signaling pathway. UVB-induced inflammatory responses were diminished by NO-sulindac as observed by a remarkable reduction in the levels of phosphorylated MAP Kinases Erk1/2, p38 and JNK1/2. In this regard, NO-sulindac also inhibited NFκB by enhancing IκBα as evidenced by the reduced expression of iNOS and COX-2, the direct NFκB transcription target proteins. NO-sulindac significantly diminished the progression of benign lesions to invasive carcinomas by suppressing the tumor aggressiveness and retarding epithelial–mesenchymal transition. A marked decrease in the expression of mesenchymal markers such as Fibronectin, N-cadherin, SNAI, Slug and Twist and an increase in epithelial cell polarity marker E-cadherin were noted in NO-sulindac-treated tumors. Our data suggest that NO-sulindac is a potent inhibitor of UVB-induced skin carcinogenesis and acts by targeting proliferation-regulatory pathways. - Highlights: ► NO-sulindac is a potent chemopreventive agent for UVB-induced skin cancer. ► NO-sulindac

  11. Synergistic induction of apoptosis by sulindac and simvastatin in A549 human lung cancer cells via reactive oxygen species-dependent mitochondrial dysfunction.

    Science.gov (United States)

    Hwang, Ki-Eun; Park, Chul; Kwon, Su-Jin; Kim, Young-Suk; Park, Do-Sim; Lee, Mi-Kyung; Kim, Byoung-Ryun; Park, Seong-Hoon; Yoon, Kwon-Ha; Jeong, Eun-Taik; Kim, Hak-Ryul

    2013-07-01

    Prevention of lung cancer is more feasible and holds greater promise when different agents are used in combination to target multiple processes during carcinogenesis. The mechanisms by which non-steroidal anti-inflammatory drugs and statins inhibit cancer cell growth and induce apoptosis are not fully understood. This study was designed to investigate lung cancer chemoprevention through a mechanism-based approach using sulindac at low doses in combination with simvastatin. We found that sulindac-induced cytotoxicity was significantly enhanced in the presence of simvastatin. The combination of sulindac and simvastatin induced more extensive caspase-dependent apoptosis in A549 cells compared to that induced with either drug alone. The combination of sulindac and simvastatin also increased the loss of mitochondrial transmembrane potential (∆Ψm) and the cytosolic release of cytochrome c. In addition, ROS generation in cells treated with both sulindac and simvastatin was markedly increased compared to cells treated with either sulindac or simvastatin alone. The enhancement of ROS generation by sulindac and simvastatin was abrogated by pretreatment with NAC, which also prevented apoptosis and mitochondrial dysfunction induced by sulindac and simvastatin. These results suggest that sulindac and simvastatin-induced ROS generation in A549 lung cancer cells causes their accumulation in mitochondria, triggering the release of apoptogenic molecules from the mitochondria to the cytosol, and thus leading to caspase activation and cell death.

  12. Nitric oxide-releasing sulindac is a novel skin cancer chemopreventive agent for UVB-induced photocarcinogenesis.

    Science.gov (United States)

    Chaudhary, Sandeep C; Singh, Tripti; Kapur, Puneet; Weng, Zhiping; Arumugam, Aadithya; Elmets, Craig A; Kopelovich, Levy; Athar, Mohammad

    2013-05-01

    Nitric oxide (NO)-releasing non-steroidal anti-inflammatory drugs (NO-NSAIDs) which have been synthesized to reduce gastro-intestinal and cardiovascular toxicities of NSAIDs, possess anti-proliferative, pro-apoptotic and anti-cancer activities. Here, we show that NO-sulindac inhibited UVB-induced skin tumorigenesis in SKH-1 hairless mice. Topical application of NO-sulindac reduced tumor incidence, number (psulindac in this study. A reduced expression of PCNA and cyclin D1 associated with the dampening of cell cycle progression was observed. The mechanism of this inhibition was related to the reduction in UVB-induced Notch signaling pathway. UVB-induced inflammatory responses were diminished by NO-sulindac as observed by a remarkable reduction in the levels of phosphorylated MAP Kinases Erk1/2, p38 and JNK1/2. In this regard, NO-sulindac also inhibited NFκB by enhancing IκBα as evidenced by the reduced expression of iNOS and COX-2, the direct NFκB transcription target proteins. NO-sulindac significantly diminished the progression of benign lesions to invasive carcinomas by suppressing the tumor aggressiveness and retarding epithelial-mesenchymal transition. A marked decrease in the expression of mesenchymal markers such as Fibronectin, N-cadherin, SNAI, Slug and Twist and an increase in epithelial cell polarity marker E-cadherin were noted in NO-sulindac-treated tumors. Our data suggest that NO-sulindac is a potent inhibitor of UVB-induced skin carcinogenesis and acts by targeting proliferation-regulatory pathways.

  13. Growth inhibition and apoptosis induction of Sulindac on Human gastric cancer cells

    Institute of Scientific and Technical Information of China (English)

    Yun-Lin Wu; Bo Sun; Xue-Jun Zhang; Sheng-Nian Wang; Heng-Yi He; Min-Min Qiao; Jie Zhong; Jia-Yu Xu

    2001-01-01

    AIM: To evaluate the effects of sulindac in inducing growth inhibition and apoptosis of human gastric cancer cells in comparison with human hepatocellular carcinoma (HCC)cells. METHODS: The human gastric cancer cell lines MKN45 and MKN28 and human hepatocellular carcinoma cell lines HepG2and SMMC7721 were used for the study. Anti-proliferative effect was measured by MTT assay, and apoptosis was determined by Hoechst-33258 staining, electronography and DNA fragmentation. The protein of cyclooxygenase-2 (COX(2) and Bcl-2 were detected by Westem dot blotting. RESULTS: Sulindac could initiate growth inhibition and apoptosis of MKN45, MKN28, HepG2 and SMMC7721 cells in a dose-and time-dependent manner. Growth inhibitory activity and apoptosis were more sensitive in HepG2 cells than in SMMC7721 cells, MKN45 and MKN28 cells. After 24hours incubation with sulindac at 2mmol. L-1 and 4mmol.L-1, the level of COX-2 and Bcl-2 protein were lowered in MKN45, SMMC7721 and HepG2 cells but not in MKN28 cells. CONCLUSION: Sulindac could inhibit the growth of gastric cancer cells and HCC cells effectively in vitro by apoptosis induction, which was associated with regression of COX-2and Bcl-2 expression. The growth inhibition and apoptosis of HCC cells were greater then that of human gastric cancer cells. The different effects of apoptosis in gastric cancer cells may be related to the differentiation of the cells.

  14. Effects of intervention with sulindac and inulin/VSL#3 on mucosal and luminal factors in the pouch of patients with familial adenomatous polyposis

    NARCIS (Netherlands)

    Friederich, P.; Verschuur, J.; Heumen, B.W. van; Schaap-Roelofs, H.M.J.; Berkhout, M.; Nagtegaal, I.D.; Oijen, M.G.H. van; Krieken, J.H. van; Peters, W.H.M.; Nagengast, F.M.

    2011-01-01

    BACKGROUND/AIM: In order to define future chemoprevention strategies for adenomas or carcinomas in the pouch of patients with familial adenomatous polyposis (FAP), a 4-weeks intervention with (1) sulindac, (2) inulin/VSL#3, and (3) sulindac/inulin/VSL#3 was performed on 17 patients with FAP in a sin

  15. COX inhibitors Indomethacin and Sulindac derivatives as antiproliferative agents: synthesis, biological evaluation, and mechanism investigation.

    Science.gov (United States)

    Chennamaneni, Snigdha; Zhong, Bo; Lama, Rati; Su, Bin

    2012-10-01

    Cyclooxygenase (COX) inhibitors Indomethacin and its structural analogs Sulindac exhibit cell growth inhibition and apoptosis inducing activities in various cancer cell lines via COX independent mechanisms. In this study, the molecular structures of Indomethacin and Sulindac were used as starting scaffolds to design novel analogs and their effects on the proliferation of human cancer cells were evaluated. Compared to Indomethacin and Sulindac inhibiting cancer cell proliferation with IC(50)s of more than 1 mM, the derivatives displayed significantly increased activities. Especially, one of the Indomethacin analogs inhibited the growth of a series of cancer cell lines with IC(50)s around 0.5 μM-3 μM. Mechanistic investigation revealed that the new analog was in fact a tubulin inhibitor, although the parental compound Indomethacin did not show any tubulin inhibitory activity. Tubulin polymerization assay indicated this compound inhibited tubulin assembly at high concentrations, but promoted this process at low concentrations which is a very unique mechanism. The binding mode of this compound in tubulin was predicted using the molecular docking simulation.

  16. The effect of sulindac, a non-steroidal anti-inflammatory drug, attenuates inflammation and fibrosis in a mouse model of chronic pancreatitis

    Directory of Open Access Journals (Sweden)

    Bai Han

    2012-08-01

    Full Text Available Abstract Background Chronic pancreatitis is characterized by progressive fibrosis, pain and loss of exocrine and endocrine functions. The long-standing chronic pancreatitis and its associated pancreatic fibrosis are the most common pathogenic events involved in human pancreatic carcinogenesis, but the therapeutic strategies to chronic pancreatitis and the chemoprevention of pancreatic carcinogenesis are very limited. Methods We investigated the effect of sulindac, a non-steroidal anti-inflammatory drug (NSAID, on inhibition of chronic pancreatitis in a caerulein induced chronic pancreatitis mouse model. Results Sulindac significantly reduced the severity of chronic pancreatitis including the extent of acini loss, inflammatory cell infiltration and stromal fibrosis. The protein expression of phosphorylation of MEK/ERK was inhibited in the chronic pancreatic tissues by sulindac treatment as measured by Western blot assay. The levels of inflammatory cytokines including TNF-α and MCP-1 were also significantly decreased with sulindac treatment, as well as the expression of TGF-β, PDGF-β, SHH and Gli in the chronic pancreatic tissue detected by qPCR assay and confirmed by western blot assay. The activation of pancreatic satellet cells was also inhibited by sulindac as measured by the activity of α-smooth muscle actin (α-SMA in the pancreatic tissue of chronic pancreatitis. Conclusions Sulindac is a promising reagent for the treatment of chronic pancreatitis via inhibition of inflammatory cell infiltration and stromal fibrosis, the inhibitory effect of sulindac on chronic pancreatitis may through targeting the activation ERK/MAPK signaling pathway.

  17. The influence of polymorphism on the manufacturability and in vitro dissolution of sulindac-containing hard gelatin capsules.

    Science.gov (United States)

    Guadalupe Sánchez-González, Elizabeth; Yépez-Mulia, Lilian; Jesús Hernández-Abad, Vicente; Jung Cook, Helgi

    2015-05-01

    Drug polymorphism could affect drug product dissolution, manufacturability, stability and bioavailability/bioequivalence. The impact of polymorphism on the manufacturability and in vitro dissolution profiles of sulindac capsules has not been studied yet. To evaluate the impact of polymorphism on the manufacturability and in vitro dissolution of sulindac hard gelatin capsules. Sulindac crystal forms I and II (SLDI and SLDII, respectively) were prepared and characterized. Powder formulations containing one of the polymorphs, lactose and magnesium stearate (at three different levels) were prepared and their flow properties determined. Hard gelatin capsules were filled with the formulations and tested for fill-weight variations. Drug dissolution for SLDI- and SLDII-containing hard gelatin capsules was determined. Differences in flow properties for each polymorph were observed, as well as for their formulations, which in turn affected capsule weight homogeneity. Statistically significant differences in the rate and extent of drug release were observed between SLDI- and SLDII-containing capsules. Formulations containing SLDI showed a better manufacturability and a better dissolution profile than those with SLDII. Sulindac crystalline form I was the best candidate for hard gelatin capsule formulation because of its technological and in vitro dissolution properties.

  18. Sulindac inhibits beta-catenin expression in normal-appearing colon of hereditary nonpolyposis colorectal cancer and familial adenomatous polyposis patients

    NARCIS (Netherlands)

    Koornstra, JJ; Rijcken, FEM; Oldenhuis, CNAM; Zwart, N; van der Sluis, T; Hollema, H; deVries, EGE; Keller, JJ; Offerhaus, JA; Giardiello, FM; Kleibeuker, JH

    2005-01-01

    Sulindac reduces colorectal cancer risk in genetically susceptible humans and animals. The molecular mechanisms underlying these effects are incompletely understood. Many studies suggest an important role for induction of apoptosis involving the mitochondrial pathway and the death receptor pathway.

  19. Multistage vector delivery of sulindac and silymarin for prevention of colon cancer.

    Science.gov (United States)

    Scavo, Maria Principia; Gentile, Emanuela; Wolfram, Joy; Gu, Jianhua; Barone, Michele; Evangelopoulos, Michael; Martinez, Jonathan O; Liu, Xuewu; Celia, Christian; Tasciotti, Ennio; Vilar, Eduardo; Shen, Haifa

    2015-12-01

    Familial adenomatous polyposis (FAP) is an inherited condition secondary to germline mutations in the APC gene, thus resulting in the formation of hundreds of colonic adenomas that eventually progress into colon cancer. Surgical removal of the colon remains the only treatment option to avoid malignancy, as long-term exposure to chemopreventive agents such as sulindac (a non-steroidal anti-inflammatory drug) and silymarin (phytoestrogen) is not feasible. Here, we have developed a multistage silicon-based drug delivery platform for sulindac and silymarin that preferentially interacts with colon cancer cells as opposed to normal intestinal mucosa. Preferential binding and internalization of these drugs into colon cancer cells was obtained using a targeting strategy against the protein meprin A, which we demonstrate is overexpressed in human colon cancer cells and in the small intestine of Apc(Min/+) mice. We propose that this delivery system could potentially be used to reduce drug-induced side effects in FAP patients, thus enabling long-term prevention of adenoma formation.

  20. Effects of sulindac and naproxen in patients with chronic glomerular disease

    DEFF Research Database (Denmark)

    Kamper, A L; Strandgaard, S; Christensen, P

    1986-01-01

    Eight patients with chronic glomerulonephritis were treated with either naproxen or sulindac in an open randomized study to observe their effects on the urinary excretion of prostaglandins and renal function. Both drugs were given for 7 days. Naproxen caused a decrease (p less than 0.01) of 80......% in prostaglandin PGE2 and decrease (p less than 0.01) of 55% in prostaglandin PGF2 alpha. Sulindac caused a decrease (p = 0.01) of 37% in PGE2 and a decrease (p less than 0.05) in PGF2 alpha of 13%. The decrease in urinary excretion of prostaglandins were greater (p less than 0.05) during the naproxen treatment....... Naproxen caused a decrease (p less than 0.05) in 24-hour creatinine clearance of 14 ml/min, an increase (p less than 0.05) in plasma urea of 1.0 mmol/l, an increase (p less than 0.05) in plasma potassium of 0.4 mmol/l and a decrease (p less than 0.01) in 24-hour urinary excretion of albumin of 11 mumol...

  1. Phospho-sulindac (OXT-922) inhibits the growth of human colon cancer cell lines: a redox/polyamine-dependent effect.

    Science.gov (United States)

    Huang, Liqun; Zhu, Caihua; Sun, Yu; Xie, Gang; Mackenzie, Gerardo G; Qiao, George; Komninou, Despina; Rigas, Basil

    2010-11-01

    Non-steroidal anti-inflammatory drugs such as sulindac are promising chemoprevention agents against colon cancer, but their weak potency and side effects limit their use for both chemoprevention and chemotherapy. Here, we evaluated the effect of a new sulindac derivative, phospho-sulindac or OXT-922, on the growth of human cancer cell lines and its mechanism of action. OXT-922 inhibited the growth of human cancer cell lines originating from colon, pancreas and breast ~11- to 30-fold more potently than sulindac. This effect was mediated by a strong cytokinetic effect. Compared with control, OXT-922 inhibited cell proliferation by up to 67%, induced apoptosis 4.1-fold over control and blocked the G(1) to S cell cycle phase transition. OXT-922 suppressed the levels of cell cycle regulating proteins, including cyclins D(1) and D(3) and Cyclin-dependent kinases (CDK) 4 and 6. The levels of intracellular reactive oxygen species (ROS), especially those of mitochondrial O₂ⁱ⁻, were markedly elevated (5.5-fold) in response to OXT-922. ROS collapsed the mitochondrial membrane potential and triggered apoptosis, which was largely abrogated by antioxidants. OXT-922 suppressed nuclear factor-kappaB activation and downregulated thioredoxin-1 expression. It also suppressed the production of prostaglandin E(2) and decreased cyclooxygenase-1 expression. Similar to sulindac, OXT-922 enhanced spermidine/spermine N(1)-acetyltransferase activity, reduced the cellular polyamine content and synergized with difluoromethylornithine to inhibit cancer cell proliferation and induce apoptosis. Our results suggest that OXT-922 possesses promising anticancer properties and deserves further evaluation.

  2. Sulfide Mineralogy and Geochemistry

    Science.gov (United States)

    Dilles, John

    2007-02-01

    Reviews in Mineralogy and Geochemistry Series, Volume 61 David J. Vaughan, Editor Geochemical Society and Mineralogical Society of America; ISBN 0-939950-73-1 xiii + 714 pp.; 2006; $40. Sulfide minerals as a class represent important minor rock-forming minerals, but they are generally known as the chief sources of many economic metallic ores. In the past two decades, sulfide research has been extended to include important roles in environmental geology of sulfide weathering and resultant acid mine drainage, as well as in geomicrobiology in which bacteria make use of sulfides for metabolic energy sources. In the latter respect, sulfides played an important role in early evolution of life on Earth and in geochemical cycling of elements in the Earth's crust and hydrosphere.

  3. Curcumin enhances the lung cancer chemopreventive efficacy of phospho-sulindac by improving its pharmacokinetics.

    Science.gov (United States)

    Cheng, Ka-Wing; Wong, Chi C; Mattheolabakis, George; Xie, Gang; Huang, Liqun; Rigas, Basil

    2013-09-01

    Phospho-sulindac (PS) is a safe sulindac derivative with promising anticancer efficacy in colon cancer. We evaluated whether its combination with curcumin could enhance the efficacy in the treatment of lung cancer. Curcumin, the principal bioactive component in turmeric, has demonstrated versatile capabilities to modify the therapeutic efficacy of a wide range of anticancer agents. Here, we evaluated the effect of co-administration of curcumin on the anticancer activity of PS in a mouse xenograft model of human lung cancer. Curcumin enhanced the cellular uptake of PS in human lung and colon cancer cell lines. To assess the potential synergism between curcumin and PS in vivo, curcumin was suspended in 10% Tween-80 or formulated in micellar nanoparticles and given to mice by oral gavage prior to the administration of PS. Both formulations of curcumin significantly improved the pharmacokinetic profiles of PS, with the 10% Tween-80 suspension being much more effective than the nanoparticle formation. However, curcumin did not exhibit any significant modification of the metabolite profile of PS. Furthermore, in a mouse subcutaneous xenograft model of human lung cancer, PS (200 mg/kg) in combination with curcumin (500 mg/kg) suspended in 10% Tween-80 (51% inhibition, p<0.05) was significantly more efficacious than PS plus micelle curcumin (30%) or PS (25%) or curcumin alone (no effect). Consistent with the improved pharmacokinetics, the combination treatment group had higher levels of PS and its metabolites in the xenografts compared to PS alone. Our results show that curcumin substantially improves the pharmacokinetics of PS leading to synergistic inhibition of the growth of human lung cancer xenografts, representing a promising drug combination.

  4. Optimisation and validation of a fast HPLC method for the quantification of sulindac and its related impurities.

    Science.gov (United States)

    Krier, Fabrice; Brion, Michaël; Debrus, Benjamin; Lebrun, Pierre; Driesen, Aurélie; Ziemons, Eric; Evrard, Brigitte; Hubert, Philippe

    2011-03-25

    The European Pharmacopoeia describes a liquid chromatography (LC) method for the quantification of sulindac, using a quaternary mobile phase including chloroform and with a rather long run time. In the present study, a new method using a short sub-2 μm column, which can be used on a classical HPLC system, was developed. The new LC conditions (without chloroform) were optimised by means of a new methodology based on design of experiments in order to obtain an optimal separation. Four factors were studied: the duration of the initial isocratic step, the percentage of organic modifier at the beginning of the gradient, the percentage of organic modifier at the end of the gradient and the gradient time. The optimal condition allows the separation of sulindac and of its 3 related impurities in 6 min instead of 18 min. Finally, the method was successfully validated using an accuracy profile approach in order to demonstrate its ability to accurately quantify these compounds.

  5. Topical phospho-sulindac (OXT-328) is effective in the treatment of non-melanoma skin cancer.

    Science.gov (United States)

    Cheng, Ka Wing; Mattheolabakis, George; Wong, Chi C; Ouyang, Nengtai; Huang, Liqun; Constantinides, Panayiotis P; Rigas, Basil

    2012-10-01

    Phospho-sulindac (P-S, OXT-328), a novel sulindac derivative, has shown superior anticancer efficacy and safety compared to sulindac. In this study, we investigated the efficacy of topical P-S hydrogel in the treatment of non-melanoma skin cancer in preclinical models. P-S is a potent inhibitor of A431 epidermoid carcinoma in vitro and achieves this effect by inhibiting cell proliferation and inducing apoptosis. The anticancer efficacy of topical and oral P-S was further evaluated in mice bearing A431 intradermal xenografts. Compared to the controls, topical P-S hydrogel inhibited the A431 xenografts by 70.5% (p500 nmol/g tumor tissue) of intact P-S in the tumors, accounting for 92.5% of the total metabolites in the A431 xenografts. This local delivery of high levels of intact P-S to the A431 xenografts is an important contributor to the potent activity of topical P-S and no local or systemic side effects were noted in the treatment group. Thus, topical P-S is a promising treatment modality against non-melanoma skin cancer and merits further evaluation.

  6. The influence of sulindac on diabetic cardiomyopathy: a non-invasive evaluation by Doppler echocardiography in streptozotocin-induced diabetic rats.

    Science.gov (United States)

    Krishna, Kota M; Gopal, Gopisetty S; Chalam, Chitrapu R V; Madan, Kalagara; Kumar, Veeravalli K; Prakash, Gomedhikam J; Annapurna, Akula

    2005-08-01

    The aim of the present study was to investigate the cardioprotective activity of sulindac as an aldose reductase inhibitor in the development of cardiomyopathy by non-invasive techniques; M-mode and Doppler echocardiography. Diabetes was induced by streptozotocin (45 mg/kg, iv) in the Sprague-Dawley rats. Echocardiography, biochemical and histological studies were carried out in normal control, diabetic untreated, diabetic vehicle (sodium carboxy methyl cellulose, 1%, po) and sulindac (6 mg/kg and 20 mg/kg, po) treated animals at varying time intervals. In the diabetic untreated and vehicle treated rats at 12 weeks after induction of diabetes, there was a significant decrease in the E-wave, an increase in the A-wave and corresponding decrease in the E/A ratio was observed. Significant decrease in the Eat was found after 12 weeks (P rats (P rats, whereas in the sulindac (6 mg/kg) treated rats, minimal necrosis was found, with no evidence of necrosis in sulindac (20 mg/kg) group. Our results show for the first time that sulindac has a cardioprotective activity as this agent prevented the development of left ventricular dysfunction in STZ-induced diabetic rats in the 12-week chronic study.

  7. Sulindac inhibits pancreatic carcinogenesis in LSL-KrasG12D-LSL-Trp53R172H-Pdx-1-Cre mice via suppressing aldo-keto reductase family 1B10 (AKR1B10).

    Science.gov (United States)

    Li, Haonan; Yang, Allison L; Chung, Yeon Tae; Zhang, Wanying; Liao, Jie; Yang, Guang-Yu

    2013-09-01

    Sulindac has been identified as a competitive inhibitor of aldo-keto reductase 1B10 (AKR1B10), an enzyme that plays a key role in carcinogenesis. AKR1B10 is overexpressed in pancreatic ductal adenocarcinoma (PDAC) and exhibits lipid substrate specificity, especially for farnesyl and geranylgeranyl. There have been no studies though showing that the inhibition of PDAC by sulindac is via inhibition of AKR1B10, particularly the metabolism of farnesyl/geranylgeranyl and Kras protein prenylation. To determine the chemopreventive effects of sulindac on pancreatic carcinogenesis, 5-week-old LSL-Kras(G12D)-LSL-Trp53(R172H)-Pdx-1-Cre mice (Pan(kras/p53) mice) were fed an AIN93M diet with or without 200 p.p.m. sulindac (n = 20/group). Kaplan-Meier survival analysis showed that average animal survival in Pan(kras/p53) mice was 143.7 ± 8.8 days, and average survival with sulindac was increased to 168.0 ± 8.8 days (P sulindac, the incidence of PDAC was reduced to 56% (P sulindac significantly decreased Ki-67-labeled cell proliferation and markedly reduced the expression of phosphorylated extracellular signal-regulated kinases 1 and 2 (ERK1/2), c-Raf and mitogen-activated protein kinase kinase 1 and 2. In in vitro experiments with PDAC cells from Pan(kras/p53) mice, sulindac exhibited dose-dependent inhibition of AKR1B10 activity. By silencing AKR1B10 expression through small interfering RNA or by sulindac treatment, these in vitro models showed a reduction in Kras and human DNA-J homolog 2 protein prenylation, and downregulation of phosphorylated C-raf, ERK1/2 and MEK1/2 expression. Our results demonstrate that sulindac inhibits pancreatic carcinogenesis by the inhibition of Kras protein prenylation by targeting AKR1B10.

  8. Interstellar hydrogen sulfide.

    Science.gov (United States)

    Thaddeus, P.; Kutner, M. L.; Penzias, A. A.; Wilson, R. W.; Jefferts, K. B.

    1972-01-01

    Hydrogen sulfide has been detected in seven Galactic sources by observation of a single line corresponding to the rotational transition from the 1(sub 10) to the 1(sub 01) levels at 168.7 GHz. The observations show that hydrogen sulfide is only a moderately common interstellar molecule comparable in abundance to H2CO and CS, but somewhat less abundant than HCN and much less abundant than CO.

  9. Inhibitory effect of herbal remedy PERVIVO and anti-inflammatory drug sulindac on L-1 sarcoma tumor growth and tumor angiogenesis in Balb/c mice.

    Science.gov (United States)

    Skopiński, P; Bałan, B J; Kocik, J; Zdanowski, R; Lewicki, S; Niemcewicz, M; Gawrychowski, K; Skopińska-Różewska, E; Stankiewicz, W

    2013-01-01

    Anticancer activity of many herbs was observed for hundreds of years. They act as modifiers of biologic response, and their effectiveness may be increased by combining multiple herbal extracts . PERVIVO, traditional digestive herbal remedy, contains some of them, and we previously described its antiangiogenic activity. Numerous studies documented anticancer effects of nonsteroidal anti-inflammatory drugs. We were the first to show that sulindac and its metabolites inhibit angiogenesis. In the present paper the combined in vivo effect of multicomponent herbal remedy PERVIVO and nonsteroidal anti-inflammatory drug sulindac on tumor growth, tumor angiogenesis, and tumor volume in Balb/c mice was studied. These effects were checked after grafting cells collected from syngeneic sarcoma L-1 tumors into mice skin. The strongest inhibitory effect was observed in experimental groups treated with PERVIVO and sulindac together. The results of our investigation showed that combined effect of examined drugs may be the best way to get the strongest antiangiogenic and antitumor effect.

  10. Combination of atorvastatin with sulindac or naproxen profoundly inhibits colonic adenocarcinomas by suppressing the p65/β-catenin/cyclin D1 signaling pathway in rats.

    Science.gov (United States)

    Suh, Nanjoo; Reddy, Bandaru S; DeCastro, Andrew; Paul, Shiby; Lee, Hong Jin; Smolarek, Amanda K; So, Jae Young; Simi, Barbara; Wang, Chung Xiou; Janakiram, Naveena B; Steele, Vernon; Rao, Chinthalapally V

    2011-11-01

    Evidence supports the protective role of nonsteroidal anti-inflammatory drugs (NSAID) and statins against colon cancer. Experiments were designed to evaluate the efficacies atorvastatin and NSAIDs administered individually and in combination against colon tumor formation. F344 rats were fed AIN-76A diet, and colon tumors were induced with azoxymethane. One week after the second azoxymethane treatment, groups of rats were fed diets containing atorvastatin (200 ppm), sulindac (100 ppm), naproxen (150 ppm), or their combinations with low-dose atorvastatin (100 ppm) for 45 weeks. Administration of atorvastatin at 200 ppm significantly suppressed both adenocarcinoma incidence (52% reduction, P = 0.005) and multiplicity (58% reduction, P = 0.008). Most importantly, colon tumor multiplicities were profoundly decreased (80%-85% reduction, P sulindac or naproxen. Also, a significant inhibition of colon tumor incidence was observed when given a low-dose atorvastatin with either sulindac (P = 0.001) or naproxen (P = 0.0005). Proliferation markers, proliferating cell nuclear antigen, cyclin D1, and β-catenin in tumors of rats exposed to sulindac, naproxen, atorvastatin, and/or combinations showed a significant suppression. Importantly, colon adenocarcinomas from atorvastatin and NSAIDs fed animals showed reduced key inflammatory markers, inducible nitric oxide synthase and COX-2, phospho-p65, as well as inflammatory cytokines, TNF-α, interleukin (IL)-1β, and IL-4. Overall, this is the first report on the combination treatment using low-dose atorvastatin with either low-dose sulindac or naproxen, which greatly suppress the colon adenocarcinoma incidence and multiplicity. Our results suggest that low-dose atorvastatin with sulindac or naproxen might potentially be useful combinations for colon cancer prevention in humans.

  11. Sulfide oxidation in a biofilter

    DEFF Research Database (Denmark)

    Pedersen, Claus Lunde; Dezhao, Liu; Hansen, Michael Jørgen;

    Observed hydrogen sulfide uptake rates in a biofilter treating waste air from a pig farm were too high to be explained within conventional limits of sulfide solubility, diffusion in a biofilm and bacterial metabolism. Clone libraries of 16S and 18S rRNA genes from the biofilter found no sulfide o...... higher hydrogen sulfide uptake followed by oxidation catalyzed by iron-containing enzymes such as cytochrome c oxidase in a process uncoupled from energy conservation....

  12. Sulfide oxidation in a biofilter

    DEFF Research Database (Denmark)

    Pedersen, Claus Lunde; Liu, Dezhao; Hansen, Michael Jørgen;

    2012-01-01

    Observed hydrogen sulfide uptake rates in a biofilter treating waste air from a pig farm were too high to be explained within conventional limits of sulfide solubility, diffusion in a biofilm and bacterial metabolism. Clone libraries of 16S and 18S rRNA genes from the biofilter found no sulfide o...... higher hydrogen sulfide uptake followed by oxidation catalyzed by iron-containing enzymes such as cytochrome c oxidase in a process uncoupled from energy conservation....

  13. Phospho-sulindac inhibits pancreatic cancer growth: NFATc1 as a drug resistance candidate.

    Science.gov (United States)

    Murray, Onika T; Wong, Chi C; Vrankova, Kvetoslava; Rigas, Basil

    2014-02-01

    Phospho-sulindac (P-S), a promising anticancer agent, is efficacious in pre-clinical models of human cancer and is apparently safe. Here, we studied the effect of P-S on pancreatic cancer growth. We found that P-S strongly inhibits the growth of human pancreatic cancer cells in vitro, is efficacious in inhibiting the growth of pancreatic xenografts in nude mice, and has an excellent safety profile. Microarray analysis revealed that P-S induced the expression of nuclear factor of activated T-cells, isoform c1 (NFATc1) gene. NFATc1, a calcineurin-responsive transcription factor associated with aggressive pancreatic cancer. The role of increased NFATc1 expression on the growth inhibitory effect of P-S on cancer growth was evaluated by silencing or by overexpressing it both in vitro and in vivo. We found that when the expression of NFATc1 was abrogated by RNAi, pancreatic cancer cells were more responsive to treatment with P-S. Conversely, overexpressing the NFATc1 gene made the pancreatic cancer cells less responsive to treatment with P-S. NFATc1 likely mediates drug resistance to P-S and is an unfavorable prognostic factor that predicts poor tumor response. We also demonstrated that NFATc1-mediated resistance can be overcome by cyclosporin A (CsA), an NFAT inhibitor, and that the combination of P-S and CsA synergistically inhibited pancreatic cancer cell growth. In conclusion, our preclinical data establish P-S as an efficacious drug for pancreatic cancer in preclinical models, which merits further evaluation.

  14. Sulfide detoxification in plant mitochondria.

    Science.gov (United States)

    Birke, Hannah; Hildebrandt, Tatjana M; Wirtz, Markus; Hell, Rüdiger

    2015-01-01

    In contrast to animals, which release the signal molecule sulfide in small amounts from cysteine and its derivates, phototrophic eukaryotes generate sulfide as an essential intermediate of the sulfur assimilation pathway. Additionally, iron-sulfur cluster turnover and cyanide detoxification might contribute to the release of sulfide in mitochondria. However, sulfide is a potent inhibitor of cytochrome c oxidase in mitochondria. Thus, efficient sulfide detoxification mechanisms are required in mitochondria to ensure adequate energy production and consequently survival of the plant cell. Two enzymes have been recently described to catalyze sulfide detoxification in mitochondria of Arabidopsis thaliana, O-acetylserine(thiol)lyase C (OAS-TL C), and the sulfur dioxygenase (SDO) ethylmalonic encephalopathy protein 1 (ETHE1). Biochemical characterization of sulfide producing and consuming enzymes in mitochondria of plants is fundamental to understand the regulatory network that enables mitochondrial sulfide homeostasis under nonstressed and stressed conditions. In this chapter, we provide established protocols to determine the activity of the sulfide releasing enzyme β-cyanoalanine synthase as well as sulfide-consuming enzymes OAS-TL and SDO. Additionally, we describe a reliable and efficient method to purify OAS-TL proteins from plant material.

  15. Sulfide oxidation in a biofilter

    DEFF Research Database (Denmark)

    Pedersen, Claus Lunde; Liu, Dezhao; Hansen, Michael Jørgen

    2012-01-01

    oxidizing bacteria but several fungal families including Trichocomaceae. A positive correlation was found between the presence of mold and sulfide uptake. However there have been no reports on fungi metabolizing hydrogen sulfide. We hypothesize that the mold increases the air exposed surface, enabling...... higher hydrogen sulfide uptake followed by oxidation catalyzed by iron-containing enzymes such as cytochrome c oxidase in a process uncoupled from energy conservation....

  16. Sulindac attenuates valproic acid-induced oxidative stress levels in primary cultured cortical neurons and ameliorates repetitive/stereotypic-like movement disorders in Wistar rats prenatally exposed to valproic acid.

    Science.gov (United States)

    Zhang, Yinghua; Yang, Cailing; Yuan, Guoyan; Wang, Zhongping; Cui, Weigang; Li, Ruixi

    2015-01-01

    Accumulating evidence suggests that anti-inflammatory agents and antioxidants have neuroprotective properties and may be beneficial in the treatment of neurodevelopental disorders, such as autism. In the present study, the possible neuroprotective properties of sulindac, a non-steroidal anti-inflammatory drug (NSAID), were investigated in vitro using cultured cortical neurons with valproic acid (VPA)-induced neurotoxicity, as well as in vivo through the behavioral analysis of rats prenatally exposed to VPA as a model of autism. VPA induced 4-hydroxynonenal (4-HNE) expression, reactive oxygen species (ROS) generation and decreased cell viability in primary cultured cortical neurons established from timed-pregnant (embryonic day 18) Wistar rat pups. However, co-incubation of the neurons with VPA and sulindac reduced oxidative stress and increased cell viability. The rats were administered an intraperitoneal injection with one of the following: VPA, sulindac, VPA and sulindac, or physiological saline, and their offspring were subjected to the open field test. During the test trials, repetitive/stereotypic-like movements for each rat were recorded and analyzed. The results revealed that treatment with both sulindac and VPA reduced the VPA-induced repetitive/stereotypic-like activity and the sulindac and VPA-treated animals responded better in the open field test compared to the VPA-treated animals. The results from the present study demonstrate that the antioxidant properties of sulindac may prove to be beneficial in the treatment of autism, suggesting that the upregulation of the Wnt/β-catenin signaling pathway disrupts oxidative homeostasis and facilitates susceptibility to autism.

  17. Suppression of angiogenic activity of sera from diabetic patients with non-proliferative retinopathy by compounds of herbal origin and sulindac sulfone.

    Science.gov (United States)

    Skopinski, Piotr; Szaflik, Jerzy; Duda-Król, Barbara; Nartowska, Jadwiga; Sommer, Ewa; Chorostowska-Wynimko, Joanna; Demkow, Urszula; Skopinska-Rózewska, Ewa

    2004-10-01

    Angiogenesis, the process of new blood vessel formation, is the key event in the mechanism of several pathological processes including diabetic retinopathy. The physiological control of angiogenesis depends on the balance between stimulatory and inhibitory factors. Therefore, a number of anti-angiogenic approaches has been developed, many of them based on the inhibition of the functional activity of pro-angiogenic factors. The aim of the present study was to compare the anti-angiogenic effectiveness of sulindac sulfone and some herbal compounds in the serum-induced angiogenesis test performed in Balb/c mice. Pooled sera from 35 patients with diabetes type 2 and retinopathy were used as pro-angiogenic stimuli. The strongest inhibitory effect was observed for the sulindac sulfone and ursolic acid in the highest concentration of 200 micro g/ml, as well as for the low-dosage concomitant treatment with 2 micro g/ml of epigallocatechin gallate (EGCG, green tea flavanol), ursolic acid (plant-derived triterpenoid), sulindac sulfone and convalamaroside (steroidal saponin). Combination treatment was significantly more effective than monotherapy with medium (20 micro g/ml) or lowest doses of tested compounds. The present study is the first to demonstrate the potent anti-angiogenic effect of the combination therapy comprising of plant-derived extracts and sulindac sulfone, as tested in the in vivo angiogenesis experimental model with sera of non-proliferative diabetic retinopathy patients used as the pro-angiogenic stimuli. We think that it might be the first step toward application of some of these compounds, in the future, in preventive anti-angiogenic therapy of these patients, as well, as in the treatment of later, proliferative stage of this disease.

  18. Inhibitory Effect of Herbal Remedy PERVIVO and Anti-Inflammatory Drug Sulindac on L-1 Sarcoma Tumor Growth and Tumor Angiogenesis in Balb/c Mice

    Directory of Open Access Journals (Sweden)

    P. Skopiński

    2013-01-01

    Full Text Available Anticancer activity of many herbs was observed for hundreds of years. They act as modifiers of biologic response, and their effectiveness may be increased by combining multiple herbal extracts . PERVIVO, traditional digestive herbal remedy, contains some of them, and we previously described its antiangiogenic activity. Numerous studies documented anticancer effects of nonsteroidal anti-inflammatory drugs. We were the first to show that sulindac and its metabolites inhibit angiogenesis. In the present paper the combined in vivo effect of multicomponent herbal remedy PERVIVO and nonsteroidal anti-inflammatory drug sulindac on tumor growth, tumor angiogenesis, and tumor volume in Balb/c mice was studied. These effects were checked after grafting cells collected from syngeneic sarcoma L-1 tumors into mice skin. The strongest inhibitory effect was observed in experimental groups treated with PERVIVO and sulindac together. The results of our investigation showed that combined effect of examined drugs may be the best way to get the strongest antiangiogenic and antitumor effect.

  19. Combined treatment with vitamin C and sulindac synergistically induces p53- and ROS-dependent apoptosis in human colon cancer cells.

    Science.gov (United States)

    Gong, Eun-Yeung; Shin, Yu Jin; Hwang, Ih-Yeon; Kim, Jeong Hee; Kim, Seung-Mi; Moon, Jai-Hee; Shin, Jae-Sik; Lee, Dae-Hee; Hur, Dae Young; Jin, Dong-Hoon; Hong, Seung-Woo; Lee, Won Keun; Lee, Wang-Jae

    2016-09-06

    Sulindac has anti-neoplastic properties against colorectal cancers; however, its use as a chemopreventive agent has been limited due to toxicity and efficacy concerns. Combinatorial treatment of colorectal cancers has been attempted to maximize anti-cancer efficacy with minimal side effects by administrating NSAIDs in combination with other inhibitory compounds or drugs such as l-ascorbic acid (vitamin C), which is known to exhibit cytotoxicity towards various cancer cells at high concentrations. In this study, we evaluated a combinatorial strategy utilizing sulindac and vitamin C. The death of HCT116 cells upon combination therapy occurred via a p53-mediated mechanism. The combination therapeutic resistance developed in isogenic p53 null HCT116 cells and siRNA-mediated p53 knockdown HCT116 cells, but the exogenous expression of p53 in p53 null isogenic cells resulted in the induction of cell death. In addition, we investigated an increased level of intracellular ROS (reactive oxygen species), which was preceded by p53 activation. The expression level of PUMA (p53-upregulated modulator of apoptosis), but not Bim, was significantly increased in HCT116 cells in response to the combination treatment. Taken together, our results demonstrate that combination therapy with sulindac and vitamin C could be a novel anti-cancer therapeutic strategy for p53 wild type colon cancers.

  20. Sulfide intrusion and detoxification in Zostera marina

    DEFF Research Database (Denmark)

    Hasler-Sheetal, Harald; Holmer, Marianne

    2014-01-01

    nutrition in general. By a global review of sulfide intrusion, coupled with a series of field studies and in situ experiments we elucidate sulfide intrusion and different strategies of seagrasses to sustain sulfide intrusion. Using stable isotope tracing, scanning electron microscopy with x-ray analysis...... indicating a possible role of sulfide in the sulfur nutrition beside the detoxification function. Our results suggest different adaptations of Z. marina to reduced sediments and sulfide intrusion ranging from bacterial and chemical reoxidation of sulfide to sulfate to incorporation of sulfide into organic...

  1. A novel method for improving cerussite sulfidization

    Institute of Scientific and Technical Information of China (English)

    Qi-cheng Feng; Shu-ming Wen; Wen-juan Zhao; Qin-bo Cao; Chao L

    2016-01-01

    Evaluation of flotation behavior, solution measurements, and surface analyses were performed to investigate the effects of chloride ion addition on the sulfidization of cerussite in this study. Micro-flotation tests indicate that the addition of chloride ions prior to sulfidization can significantly increase the flotation recovery of cerussite, which is attributed to the formation of more lead sulfide species on the mineral surface. Solution measurement results suggest that the addition of chloride ions prior to sulfidization induces the transformation of more sul-fide ions from pulp solution onto the mineral surface by the formation of more lead sulfide species. X-ray diffraction and energy-dispersive spectroscopy indicate that more lead sulfide species form on the mineral surface when chloride ions are added prior to sulfidization. These results demonstrate that the addition of chloride ions prior to sulfidization can significantly improve the sulfidization of cerussite, thereby enhancing the flotation performance.

  2. Prevention of sulfide oxidation in sulfide-rich waste rock

    Science.gov (United States)

    Nyström, Elsa; Alakangas, Lena

    2015-04-01

    The ability to reduce sulfide oxidation in waste rock after mine closure is a widely researched area, but to reduce and/or inhibit the oxidation during operation is less common. Sulfide-rich (ca 30 % sulfur) waste rock, partially oxidized, was leached during unsaturated laboratory condition. Trace elements such as As and Sb were relatively high in the waste rock while other sulfide-associated elements such as Cu, Pb and Zn were low compared to common sulfide-rich waste rock. Leaching of unsaturated waste rock lowered the pH, from around six down to two, resulting in continuously increasing element concentrations during the leaching period of 272 days. The concentrations of As (65 mg/L), Cu (6.9 mg/L), Sb (1.2 mg/L), Zn (149 mg/L) and S (43 g/L) were strongly elevated at the end of the leaching period. Different alkaline industrial residues such as slag, lime kiln dust and cement kiln dust were added as solid or as liquid to the waste rock in an attempt to inhibit sulfide oxidation through neo-formed phases on sulfide surfaces in order to decrease the mobility of metals and metalloids over longer time scale. This will result in a lower cost and efforts of measures after mine closure. Results from the experiments will be presented.

  3. Mechanochemical reduction of copper sulfide

    DEFF Research Database (Denmark)

    Balaz, P.; Takacs, L.; Jiang, Jianzhong

    2002-01-01

    The mechanochemical reduction of copper sulfide with iron was induced in a Fritsch P-6 planetary mill, using WC vial filled with argon and WC balls. Samples milled for specific intervals were analyzed by XRD and Mossbauer spectroscopy. Most of the reaction takes place during the first 10 min...... of milling and only FeS and Cu are found after 60 min. The main chemical process is accompanied by phase transformations of the sulfide phases as a result of milling. Djurleite partially transformed to chalcocite and a tetragonal copper sulfide phase before reduction. The cubic modification of FeS was formed...... first, transforming to hexagonal during the later stages of the process. The formation of off-stoichiometric phases and the release of some elemental sulfur by copper sulfide are also probable....

  4. Hydrogen sulfide in signaling pathways.

    Science.gov (United States)

    Olas, Beata

    2015-01-15

    For a long time hydrogen sulfide (H₂S) was considered a toxic compound, but recently H₂S (at low concentrations) has been found to play an important function in physiological processes. Hydrogen sulfide, like other well-known compounds - nitric oxide (NO) and carbon monoxide (CO) is a gaseous intracellular signal transducer. It regulates the cell cycle, apoptosis and the oxidative stress. Moreover, its functions include neuromodulation, regulation of cardiovascular system and inflammation. In this review, I focus on the metabolism of hydrogen sulfide (including enzymatic pathways of H₂S synthesis from l- and d-cysteine) and its signaling pathways in the cardiovascular system and the nervous system. I also describe how hydrogen sulfide may be used as therapeutic agent, i.e. in the cardiovascular diseases.

  5. Synthesis of furan from allenic sulfide derivatives

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    In this paper, we report the synthesis of furan derivatives from allenic sulfides. By the reaction with NaH, β-Hydroxyl allenic sulfides were found to generate furan products in excellent yields with the removal of phenylthio group. β-Aldehyde allenic sulfides were found to give similar furan products with one more substituent when treated with additional nucleophilic reagents. β-ketone allenic sulfides can also cyclize to give furan derivatives with the promotion of P2O5.

  6. Synthesis of furan from allenic sulfide derivatives

    Institute of Scientific and Technical Information of China (English)

    PENG LingLing; ZHANG Xiu; MA Jie; ZHONG ZhenZhen; ZHANG Zhe; ZHANG Yan; WANG JianBo

    2009-01-01

    In this paper, we report the synthesis of furan derivatives from allenic sulfides. By the reaction with NaH.,β-Hydroxyl allenic sulfides were found to generate furan products in excellent yields with the removal of phenylthio group.β-Aldehyde allenic sulfides were found to give similar furan products with one more substituent when treated with additional nucleophilic reagents. β-ketone allenic sulfides can also cyclize to give furan derivatives with the promotion of P2O5.

  7. Sulindac and Celecoxib regulate cell cycle progression by p53/p21 up regulation to induce apoptosis during initial stages of experimental colorectal cancer.

    Science.gov (United States)

    Vaish, Vivek; Rana, Chandan; Piplani, Honit; Vaiphei, Kim; Sanyal, Sankar Nath

    2014-03-01

    In the present study we have elaborated the putative mechanisms could be followed by the non-steroidal anti-inflammatory drugs (NSAIDs) viz. Sulindac and Celecoxib in the regulation of cell cycle checkpoints along with tumor suppressor proteins to achieve their chemopreventive effects in the initial stages of experimental colorectal cancer. Male Sprague-Dawley rats were administered with 1,2-dimethylhydrazine dihydrochloride (DMH) to produce early stages of colorectal carcinogenesis. The mRNA expression profiles of various target genes were analyzed by RT-PCR and validated by quantitative real-time PCR, whereas protein expression was analyzed by Western blotting. Nuclear localization of transcription factors or other nuclear proteins was analyzed by electrophoretic mobility shift assay and immunofluorescence. Flowcytometry was performed to analyze the differential apoptotic events and cell cycle regulation. Molecular docking studies with different target proteins were also performed to deduce the various putative mechanisms of action followed by Sulindac and Celecoxib. We observed that DMH administration has abruptly increased the proliferation of colonic cells which is macroscopically visible in the form of multiple plaque lesions and co-relates with the disturbed molecular mechanisms of cell cycle regulation. However, co-administration of NSAIDs has shown regulatory effects on cell cycle checkpoints via induction of various tumor suppressor proteins. We may conclude that Sulindac and Celecoxib could possibly follow p53/p21 mediated regulation of cell proliferation, where down regulation of NF-κB signaling and activation of PPARγ might serve as important additional events in vivo.

  8. 30 CFR 250.604 - Hydrogen sulfide.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Hydrogen sulfide. 250.604 Section 250.604... OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Well-Workover Operations § 250.604 Hydrogen sulfide. When a well-workover operation is conducted in zones known to contain hydrogen sulfide (H2S) or...

  9. 30 CFR 250.504 - Hydrogen sulfide.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Hydrogen sulfide. 250.504 Section 250.504... OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Well-Completion Operations § 250.504 Hydrogen sulfide. When a well-completion operation is conducted in zones known to contain hydrogen sulfide (H2S) or...

  10. 30 CFR 250.808 - Hydrogen sulfide.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Hydrogen sulfide. 250.808 Section 250.808... OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Production Safety Systems § 250.808 Hydrogen sulfide. Production operations in zones known to contain hydrogen sulfide (H2S) or in zones where the presence of...

  11. Nanostructured metal sulfides for energy storage.

    Science.gov (United States)

    Rui, Xianhong; Tan, Huiteng; Yan, Qingyu

    2014-09-07

    Advanced electrodes with a high energy density at high power are urgently needed for high-performance energy storage devices, including lithium-ion batteries (LIBs) and supercapacitors (SCs), to fulfil the requirements of future electrochemical power sources for applications such as in hybrid electric/plug-in-hybrid (HEV/PHEV) vehicles. Metal sulfides with unique physical and chemical properties, as well as high specific capacity/capacitance, which are typically multiple times higher than that of the carbon/graphite-based materials, are currently studied as promising electrode materials. However, the implementation of these sulfide electrodes in practical applications is hindered by their inferior rate performance and cycling stability. Nanostructures offering the advantages of high surface-to-volume ratios, favourable transport properties, and high freedom for the volume change upon ion insertion/extraction and other reactions, present an opportunity to build next-generation LIBs and SCs. Thus, the development of novel concepts in material research to achieve new nanostructures paves the way for improved electrochemical performance. Herein, we summarize recent advances in nanostructured metal sulfides, such as iron sulfides, copper sulfides, cobalt sulfides, nickel sulfides, manganese sulfides, molybdenum sulfides, tin sulfides, with zero-, one-, two-, and three-dimensional morphologies for LIB and SC applications. In addition, the recently emerged concept of incorporating conductive matrices, especially graphene, with metal sulfide nanomaterials will also be highlighted. Finally, some remarks are made on the challenges and perspectives for the future development of metal sulfide-based LIB and SC devices.

  12. Influence of arsenic on iron sulfide transformations

    NARCIS (Netherlands)

    Wolthers, M.; Butler, I.B.; Rickard, D.

    2007-01-01

    The association of arsenate, As(V), and arsenite, As(III), with disordered mackinawite, FeS, was studied in sulfide-limited (Fe:S = 1:1) and excess-sulfide (Fe:S = 1:2) batch experiments. In the absence of arsenic, the sulfide-limited experiments produce disordered mackinawite while the

  13. STUDY OF HYDROGEN SULFIDE REMOVAL FROM GROUNDWATER

    Directory of Open Access Journals (Sweden)

    T. Lupascu

    2013-06-01

    Full Text Available The process of the hydrogen sulfide removal from the underground water of the Hancesti town has been investigated. By oxygen bubbling through the water containing hydrogen sulfide, from the Hancesti well tube, sulfur is deposited in the porous structure of studied catalysts, which decreases their catalytic activity. Concomitantly, the process of adsorption / oxidation of hydrogen sulfide to sulfate take place. The kinetic research of the hydrogen sulfide removal from the Hancesti underground water, after its treatment by hydrogen peroxide, proves greater efficiency than in the case of modified carbonic adsorbents. As a result of used treatment, hydrogen sulfide is completely oxidized to sulfates

  14. Redox Biochemistry of Hydrogen Sulfide*

    OpenAIRE

    Kabil, Omer; Banerjee, Ruma

    2010-01-01

    H2S, the most recently discovered gasotransmitter, might in fact be the evolutionary matriarch of this family, being both ancient and highly reduced. Disruption of γ-cystathionase in mice leads to cardiovascular dysfunction and marked hypertension, suggesting a key role for this enzyme in H2S production in the vasculature. However, patients with inherited deficiency in γ-cystathionase apparently do not present vascular pathology. A mitochondrial pathway disposes sulfide and couples it to oxid...

  15. Hydrogen sulfide and translational medicine

    OpenAIRE

    Guo, Wei; Cheng, Ze-yu; Zhu, Yi-Zhun

    2013-01-01

    Hydrogen sulfide (H2S) along with carbon monoxide and nitric oxide is an important signaling molecule that has undergone large numbers of fundamental investigations. H2S is involved in various physiological activities associated with the regulation of homeostasis, vascular contractility, pro- and anti-inflammatory activities, as well as pro- and anti-apoptotic activities etc. However, the actions of H2S are influenced by its concentration, reaction time, and cell/disease types. Therefore, H2S...

  16. Sulfide intrusion and detoxification in seagrasses ecosystems

    DEFF Research Database (Denmark)

    Hasler-Sheetal, Harald; Holmer, Marianne

    strategies of seagrasses to sustain sulfide intrusion. Using stable isotope tracing, scanning electron microscopy with x-ray analysis, tracing sulfur compounds combined with ecosystem parameters we found different spatial, intraspecific and interspecific strategies to cope with sulfidic sediments. 1......) Tolerance, by elimination (eg. Zostera marina); where we found precipitation of sulfide as non-toxic elemental sulfur on the inner wall of the root lacunae. 2) Utilization (eg. Z. marina), where seagrasses detoxify and incorporate sulfides by active uptake and metabolize to sulfate, representing a non...

  17. Hydrogen sulfide and vascular relaxation

    Institute of Scientific and Technical Information of China (English)

    SUN Yan; TANG Chao-shu; DU Jun-bao; JIN Hong-fang

    2011-01-01

    Objective To review the vasorelaxant effects of hydrogen sulfide (H2S) in arterial rings in the cardiovascular system under both physiological and pathophysiological conditions and the possible mechanisms involved.Data sources The data in this review were obtained from Medline and Pubmed sources from 1997 to 2011 using the search terms "hydrogen sulfide" and ""vascular relaxation".Study selection Articles describing the role of hydrogen sulfide in the regulation of vascular activity and its vasorelaxant effects were selected.Results H2S plays an important role in the regulation of cardiovascular tone.The vasomodulatory effects of H2S depend on factors including concentration,species and tissue type.The H2S donor,sodium hydrosulfide (NarS),causes vasorelaxation of rat isolated aortic rings in a dose-dependent manner.This effect was more pronounced than that observed in pulmonary arterial rings.The expression of KATP channel proteins and mRNA in the aortic rings was increased compared with pulmonary artery rings.H2S is involved in the pathogenesis of a variety of cardiovascular diseases.Downregulation of the endogenous H2S pathway is an important factor in the pathogenesis of cardiovascular diseases.The vasorelaxant effects of H2S have been shown to be mediated by activation of KATP channels in vascular smooth muscle cells and via the induction of acidification due to activation of the CI/HCO3 exchanger.It is speculated that the mechanisms underlying the vasoconstrictive function of H2S in the aortic rings involves decreased NO production and inhibition of cAMP accumulation.Conclusion H2S is an important endogenous gasotransmitter in the cardiovascular system and acts as a modulator of vascular tone in the homeostatic regulation of blood pressure.

  18. Molybdenum sulfide/carbide catalysts

    Science.gov (United States)

    Alonso, Gabriel; Chianelli, Russell R.; Fuentes, Sergio; Torres, Brenda

    2007-05-29

    The present invention provides methods of synthesizing molybdenum disulfide (MoS.sub.2) and carbon-containing molybdenum disulfide (MoS.sub.2-xC.sub.x) catalysts that exhibit improved catalytic activity for hydrotreating reactions involving hydrodesulfurization, hydrodenitrogenation, and hydrogenation. The present invention also concerns the resulting catalysts. Furthermore, the invention concerns the promotion of these catalysts with Co, Ni, Fe, and/or Ru sulfides to create catalysts with greater activity, for hydrotreating reactions, than conventional catalysts such as cobalt molybdate on alumina support.

  19. Medical Functions of Hydrogen Sulfide.

    Science.gov (United States)

    Olas, Beata

    2016-01-01

    Hydrogen sulfide (H(2)S) is a gasomediator synthesized from L- and D-cysteine in various tissues. It is involved in a number of physiological and pathological processes. H(2)S exhibits antiatherosclerotic, vasodilator, and proangiogenic properties, and protects the kidney and heart from damage following ischemia/reperfusion injury. H(2)S donors may be natural or synthetic, and may be used for the safe treatment of a wide range of diseases. This review article summarizes the current state of knowledge of the therapeutic function of H(2)S.

  20. Ammonia and hydrogen sulfide removal using biochar

    Science.gov (United States)

    Reducing ammonia and hydrogen sulfide emissions from livestock facilities is an important issue for many communities and livestock producers. Ammonia has been regarded as odorous, precursor for particulate matter (PM), and contributed to livestock mortality. Hydrogen sulfide is highly toxic at elev...

  1. Micro and nano sulfide solid lubrication

    CERN Document Server

    Wang, Haidou; Liu, Jiajun

    2014-01-01

    Sulfide solid lubrication is a vital field of tribology with the potential to save both energy and materials. This book examines the low-temperature sulfuration technology developed in China, as well as two-step methods for preparing sulfide lubrication films.

  2. Sulfide toxicity kinetics of a uasb reactor

    Directory of Open Access Journals (Sweden)

    D. R. Paula Jr.

    2009-12-01

    Full Text Available The effect of sulfide toxicity on kinetic parameters of anaerobic organic matter removal in a UASB (up-flow anaerobic sludge blanket reactor is presented. Two lab-scale UASB reactors (10.5 L were operated continuously during 12 months. The reactors were fed with synthetic wastes prepared daily using glucose, ammonium acetate, methanol and nutrient solution. One of the reactors also received increasing concentrations of sodium sulfide. For both reactors, the flow rate of 16 L.d-1 was held constant throughout the experiment, corresponding to a hydraulic retention time of 15.6 hours. The classic model for non-competitive sulfide inhibition was applied to the experimental data for determining the overall kinetic parameter of specific substrate utilization (q and the sulfide inhibition coefficient (Ki. The application of the kinetic parameters determined allows prediction of methanogenesis inhibition and thus the adoption of operating parameters to minimize sulfide toxicity in UASB reactors.

  3. Effect of sulindac on improving autistic behaviors in rats%舒林酸对孤独症模型大鼠病症行为的改善作用

    Institute of Scientific and Technical Information of China (English)

    秦利燕; 戴旭芳

    2015-01-01

    Objective To test the effect of sulindac on autistic behaviors in a rat model and explore the possible mechanisms. Methods Autistic rat models were established by a single intraperitoneal injection of sodium valproate (VPA) at 12.5 days of pregnancy. The pregnant rats were treated with oral sulindac at a daily dose of 80 mg/kg until weaning of the newborn rats (23 days after being born), which were divided into control, VPA treatment, sulindac treatment, and VPA+ sulindac treatment groups. The social interaction and neuroethology of the newborn rats were evaluated at 35 days, and the levels of β-catenin and phosphorylated Gsk3βin the brain tissues were investigated by Western blotting. Results Compared with the control rats, the rats treated with VPA showed lower social interaction, longer moving time in central area, and reduced standing times. Treatment with sulindac alone resulted in no obvious changes in the social interaction or neuroethology of the newborn rats, but sulindac treatment corrected VPA-induced autistic-like behaviors. Sulindac also attenuated VPA-triggered p-Gsk3βdownregulation andβ-catenin upregulation in the prefrontal lobe, seahorse and cerebellum. Conclusion Sulindac can improve the behaviors of autistic rats possibly by suppressing Wnt signaling pathway.%目的 探讨舒林酸对孤独症模型大鼠病症行为的改善作用.方法 在大鼠怀孕12.5 d后采用一次性腹腔注射丙戊酸钠(VPA)制备孤独症大鼠模型.针对舒林酸处理组,于VPA注射后每天给大鼠口服20 mg/kg舒林酸直至断奶.将出生幼鼠分为4组:对照组,VPA处理组,舒林酸处理组及VPA联合舒林酸处理组.出生后35 d对幼鼠进行社会交往行为检测、敞箱焦虑样行为检测,并分离提取脑组织蛋白利用Western blot分析Wnt信号通路关键蛋白β-catenin与Gsk3β表达情况.结果 成功制备孤独症大鼠模型.与对照组相比,VPA处理组社会交往能力下降、在中央区活动时间增加、

  4. Sulfide oxidation as a process for the formation of copper-rich magmatic sulfides

    Science.gov (United States)

    Wohlgemuth-Ueberwasser, Cora C.; Fonseca, Raúl O. C.; Ballhaus, Chris; Berndt, Jasper

    2013-01-01

    Typical magmatic sulfides are dominated by pyrrhotite and pentlandite with minor chalcopyrite, and the bulk atomic Cu/Fe ratio of these sulfides is typically less than unity. However, there are rare magmatic sulfide occurrences that are dominated by Cu-rich sulfides (e.g., bornite, digenite, and chalcopyrite, sometimes coexisting with metallic Cu) with atomic Cu/Fe as high as 5. Typically, these types of sulfide assemblages occur in the upper parts of moderately to highly fractionated layered mafic-ultramafic intrusions, a well-known example being the Pd/Au reef in the Upper Middle Zone of the Skaergaard intrusion. Processes proposed to explain why these sulfides are so unusually rich in Cu include fractional crystallization of Fe/(Ni) monosulfide and infiltration of postmagmatic Cu-rich fluids. In this contribution, we explore and experimentally evaluate a third possibility: that Cu-rich magmatic sulfides may be the result of magmatic oxidation. FeS-dominated Ni/Cu-bearing sulfides were equilibrated at variable oxygen fugacities in both open and closed system. Our results show that the Cu/Fe ratio of the sulfide melt increases as a function of oxygen fugacity due to the preferential conversion of FeS into FeO and FeO1.5, and the resistance of Cu2S to being converted into an oxide component even at oxygen fugacities characteristic of the sulfide/sulfate transition (above FMQ + 1). This phenomenon will lead to an increase in the metal/S ratio of a sulfide liquid and will also depress its liquidus temperature. As such, any modeling of the sulfide liquid line of descent in magmatic sulfide complexes needs to address this issue.

  5. 21 CFR 177.2490 - Polyphenylene sulfide resins.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Polyphenylene sulfide resins. 177.2490 Section 177... Components of Articles Intended for Repeated Use § 177.2490 Polyphenylene sulfide resins. Polyphenylene sulfide resins (poly(1,4-phenylene sulfide) resins) may be safely used as coatings or components...

  6. Adequate hydrogen sulfide, healthy circulation

    Institute of Scientific and Technical Information of China (English)

    DU Jun-bao; CHEN Stella; JIN Hong-fang; TANG Chao-shu

    2011-01-01

    Previously,hydrogen sulfide (H2S) was considered to be a toxic gas.However,recently it was discovered that it could be produced in mammals and even in plants,throughtheproductionandmetabolismof sulfur-containing amino acids.In mammals,H2S is mainly catalyzed by cystathionine-γ-lyase (CSE),cystathionin-β-lyase (CBS) and 3-mercaptopyruvate sulfurtransferase (MPST) with the substrate of L-cysteine.Endogenous H2S exerts many important physiological and pathophysiological functions,including hypotensive action,vasorelaxation,myocardial dilation,inhibition of smooth muscle cell proliferation,and antioxidatve actions.Importantly,it plays a very important role in the pathogenesis of systemic hypertension,pulmonary hypertension,atherosclerosis,myocardialinjury,angiogenesis,hyperhomocysteinemi aandshock.Therefore,H2S is now being considered to be a novel gasotransmitter after nitric oxide and carbon monoxide in the regulation of circulatory system.

  7. Redox biochemistry of hydrogen sulfide.

    Science.gov (United States)

    Kabil, Omer; Banerjee, Ruma

    2010-07-16

    H(2)S, the most recently discovered gasotransmitter, might in fact be the evolutionary matriarch of this family, being both ancient and highly reduced. Disruption of gamma-cystathionase in mice leads to cardiovascular dysfunction and marked hypertension, suggesting a key role for this enzyme in H(2)S production in the vasculature. However, patients with inherited deficiency in gamma-cystathionase apparently do not present vascular pathology. A mitochondrial pathway disposes sulfide and couples it to oxidative phosphorylation while also exposing cytochrome c oxidase to this metabolic poison. This report focuses on the biochemistry of H(2)S biogenesis and clearance, on the molecular mechanisms of its action, and on its varied biological effects.

  8. Microbial control of hydrogen sulfide production

    Energy Technology Data Exchange (ETDEWEB)

    Montgomery, A.D.; Bhupathiraju, V.K.; Wofford, N.; McInerney, M.J. [Univ. of Oklahoma, Tulsa, OK (United States)] [and others

    1995-12-31

    A sulfide-resistant strain of Thiobacillus denitrificans, strain F, prevented the accumulation of sulfide by Desulfovibrio desulfuricans when both organisms were grown in liquid medium. The wild-type strain of T. denitrificans did not prevent the accumulation of sulfide produced by D. desulfuricans. Strain F also prevented the accumulation of sulfide by a mixed population of sulfate-reducing bacteria enriched from an oil field brine. Fermentation balances showed that strain F stoichiometrically oxidized the sulfide produced by D. desulfuricans and the oil field brine enrichment to sulfate. The ability of a strain F to control sulfide production in an experimental system of cores and formation water from the Redfield, Iowa, natural gas storage facility was also investigated. A stable, sulfide-producing biofilm was established in two separate core systems, one of which was inoculated with strain F while the other core system (control) was treated in an identical manner, but was not inoculated with strain F. When formation water with 10 mM acetate and 5 mM nitrate was injected into both core systems, the effluent sulfide concentrations in the control core system ranged from 200 to 460 {mu}M. In the test core system inoculated with strain F, the effluent sulfide concentrations were lower, ranging from 70 to 110 {mu}M. In order to determine whether strain F could control sulfide production under optimal conditions for sulfate-reducing bacteria, the electron donor was changed to lactate and inorganic nutrients (nitrogen and phosphate sources) were added to the formation water. When nutrient-supplemented formation water with 3.1 mM lactate and 10 mM nitrate was used, the effluent sulfide concentrations of the control core system initially increased to about 3,800 {mu}M, and then decreased to about 1,100 {mu}M after 5 weeks. However, in the test core system inoculated with strain F, the effluent sulfide concentrations were much lower, 160 to 330 {mu}M.

  9. Structural studies in limestone sulfidation

    Energy Technology Data Exchange (ETDEWEB)

    Fenouil, Laurent A. [Univ. of California, Berkeley, CA (United States)

    1993-05-01

    This study investigates the sulfidation of limestone at high temperatures (700--900°C) as the first step in the design of a High-Temperature Coal-Gas Clean-Up system using millimeter-size limestone particles. Several workers have found that the rate of this reaction significantly decreases after an initial 10 to 15% conversion of CaCO3 to CaS. The present work attempts to explain this feature. It is first established that millimeter-size limestone particles do not sinter at temperatures up to the CaCO3 calcination point (899°C at 1.03 bar CO2} partial pressure). It is then shown that CaS sinters rapidly at 750 to 900°C if CO2 is present in the gas phase. Scanning Electron Microscope (SEM) photographs and Electron Dispersive Spectroscopy (EDS) data reveal that the CaS product layer sinters and forms a quasi-impermeable coating around the CaCO3 grains that greatly hinders more H2S from reaching the still unreacted parts of the stone. Moreover, most of the pores initially present within the limestone structure begin to disappear or, at least, are significantly reduced in size. From then on, subsequent conversion is limited by diffusion of H2S through the CaS layer, possibly by S2- ionic diffusion. The kinetics is then adequately described by a shrinking-core model, in which a sharp front of completely converted limestone is assumed to progress toward the center of the pellet. Finally, experimental evidence and computer simulations using simple sintering models suggest that the CaS sintering, responsible for the sharp decrease in the sulfidation rate, is surface-diffusion controlled.

  10. Removal of methanethiol, dimethyl sulfide, dimethyl disulfide, and hydrogen sulfide from contaminated air by Thiobacillus thioparus TK-m.

    OpenAIRE

    Kanagawa, T; Mikami, E.

    1989-01-01

    Methanethiol, dimethyl sulfide, dimethyl disulfide, and hydrogen sulfide were efficiently removed from contaminated air by Thiobacillus thioparus TK-m and oxidized to sulfate stoichiometrically. More than 99.99% of dimethyl sulfide was removed when the load was less than 4.0 g of dimethyl sulfide per g (dry cell weight) per day.

  11. Hydrogen Sulfide Induces Oxidative Damage to RNA and DNA in a Sulfide-Tolerant Marine Invertebrate

    OpenAIRE

    Joyner-Matos, Joanna; Predmore, Benjamin L.; Stein, Jenny R.; Leeuwenburgh, Christiaan; Julian, David

    2010-01-01

    Hydrogen sulfide acts as an environmental toxin across a range of concentrations and as a cellular signaling molecule at very low concentrations. Despite its toxicity, many animals, including the mudflat polychaete Glycera dibranchiata, are periodically or continuously exposed to sulfide in their environment. We tested the hypothesis that a broad range of ecologically relevant sulfide concentrations induces oxidative stress and oxidative damage to RNA and DNA in G. dibranchiata. Coelomocytes ...

  12. Nitrate-reducing, sulfide-oxidizing bacteria as microbial oxidants for rapid biological sulfide removal.

    Science.gov (United States)

    De Gusseme, Bart; De Schryver, Peter; De Cooman, Michaël; Verbeken, Kim; Boeckx, Pascal; Verstraete, Willy; Boon, Nico

    2009-01-01

    The emission of hydrogen sulfide into the atmosphere of sewer systems induces the biological production of sulfuric acid, causing severe concrete corrosion. As a possible preventive solution, a microbial consortium of nitrate-reducing, sulfide-oxidizing bacteria (NR-SOB) was enriched in a continuously stirred tank reactor in order to develop a biological technique for the removal of dissolved sulfide. The consortium, dominated by Arcobacter sp., was capable of removing 99% of sulfide. Stable isotope fractioning of the sulfide indicated that the oxidation was a biological process. The capacity of the NR-SOB consortium for rapid removal of sulfide was demonstrated by using it as an inoculum in synthetic and real sewage. Removal rates up to 52 mg sulfide-S g VSS(-1) h(-1) were achieved, to our knowledge the highest removal rate reported so far for freshwater species in the absence of molecular oxygen. Further long-term incubation experiments revealed the capacity of the bacteria to oxidize sulfide without the presence of nitrate, suggesting that an oxidized redox reserve is present in the culture.

  13. [Fatal outcome of an hydrogen sulfide poisoning].

    Science.gov (United States)

    Querellou, E; Jaffrelot, M; Savary, D; Savry, C; Perfus, J-P

    2005-10-01

    We report a case of fatal outcome poisoning by massive exposure to hydrogen sulfide of a sewer worker. This rare event was associated with a moderate intoxication of two members of the rescue team. The death was due to asystole and massive lung oedema. Autopsy analysis showed diffuse necrotic lesions in lungs. Hydrogen sulfide is a direct and systemic poison, produced by organic matter decomposition. The direct toxicity mechanism is still unclear. The systemic toxicity is due to an acute toxicity by oxygen depletion at cellular level. It is highly diffusable and potentially very dangerous. At low concentration, rotten egg smell must trigger hydrogen sulfide suspicion since at higher concentration it is undetectable, making intoxication possible. In case of acute intoxication, there is an almost instantaneous cardiovascular failure and a rapid death. Hydrogen sulfide exposure requires prevention measures and more specifically the use of respiratory equipment for members of the rescue team.

  14. Hydrogen sulfide in hemostasis: friend or foe?

    Science.gov (United States)

    Olas, Beata

    2014-06-25

    Hydrogen sulfide (H2S) is a well known toxic gas that is synthesized from the amino acids: cysteine (Cys) and homocysteine (Hcy) by three enzymes: cystathionine-β-synthase (CBS), cystathionine-γ-lyase (CSE) and mercaptopyruvate sulfurtransferase (3-MST). Hydrogen sulfide, like carbon monoxide (CO) or nitric oxide (NO) is a signaling molecule in different biological systems, including the cardiovascular system. Moreover, hydrogen sulfide plays a role in the pathogenesis of various cardiovascular diseases. It modulates different elements of hemostasis (activation of blood platelet, and coagulation process) as well as proliferation and apoptosis of vascular smooth muscle cells. However, the biological role and the therapeutic potential of H2S is not clear. This review summarizes the different functions of hydrogen sulfide in hemostasis.

  15. Air-water transfer of hydrogen sulfide

    DEFF Research Database (Denmark)

    Yongsiri, C.; Vollertsen, J.; Rasmussen, M. R.

    2004-01-01

    The emissions process of hydrogen sulfide was studied to quantify air–water transfer of hydrogen sulfide in sewer networks. Hydrogen sulfide transfer across the air–water interface was investigated at different turbulence levels (expressed in terms of the Froude number) and pH using batch...... experiments. By means of the overall mass–transfer coefficient (KLa), the transfer coefficient of hydrogen sulfide (KLaH2S), referring to total sulfide, was correlated to that of oxygen (KLaO2) (i.e., the reaeration coefficient). Results demonstrate that both turbulence and pH in the water phase play...... a significant role for KLaH2S. An exponential expression is a suitable representation for the relationship between KLaH2S and the Froude number at all pH values studied (4.5 to 8.0). Because of the dissociation of hydrogen sulfide, KLaH2S increased with decreasing pH at a constant turbulence level. Relative...

  16. Mechanism of mechanical activation for sulfide ores

    Institute of Scientific and Technical Information of China (English)

    HU Hui-ping; CHEN Qi-yuan; YIN Zhou-lan; HE Yue-hui; HUANG Bai-yun

    2007-01-01

    Structural changes for mechanically activated pyrite, sphalerite, galena and molybdenite with or without the exposure to ambient air, were systematically investigated using X-ray diffraction analysis(XRD), particle size analysis, gravimetrical method, X-ray photo-electron spectroscopy(XPS) and scanning electron microscopy(SEM), respectively. Based on the above structural changes for mechanically activated sulfide ores and related reports by other researchers, several qualitative rules of the mechanisms and the effects of mechanical activation for sulfide ores are obtained. For brittle sulfide ores with thermal instability, and incomplete cleavage plane or extremely incomplete cleavage plane, the mechanism of mechanical activation is that a great amount of surface reactive sites are formed during their mechanical activation. The effects of mechanical activation are apparent. For brittle sulfide ores with thermal instability, and complete cleavage plane, the mechanism of mechanical activation is that a great amount of surface reactive sites are formed, and lattice deformation happens during their mechanical activation. The effects of mechanical activation are apparent. For brittle sulfide ores with excellent thermal stability, and complete cleavage plane, the mechanism of mechanical activation is that lattice deformation happens during their mechanical activation. The effects of mechanical activation are apparent. For sulfide ores with high toughness, good thermal stability and very excellent complete cleavage plane, the mechanism of mechanical activation is that lattice deformation happens during their mechanical activation, but the lattice deformation ratio is very small. The effects of mechanical activation are worst.

  17. Sulfide as a soil phytotoxin - A review

    Directory of Open Access Journals (Sweden)

    Leon P M Lamers

    2013-07-01

    Full Text Available In wetland soils and underwater sediments of marine, brackish and freshwater systems, the strong phytotoxin sulfide may accumulate as a result of microbial reduction of sulfate during anaerobiosis, its level depending on prevailing edaphic conditions. In this review, we compare an extensive body of literature on phytotoxic effects of this reduced sulfur compound in different ecosystem types, and review the effects of sulfide at multiple ecosystem levels: the ecophysiological functioning of individual plants, plant-microbe associations, and community effects including competition and facilitation interactions. Recent publications on multi-species interactions in the rhizosphere show even more complex mechanisms explaining sulfide resistance. It is concluded that sulfide is a potent phytotoxin, profoundly affecting plant fitness and ecosystem functioning in the full range of wetland types including coastal systems, and at several levels. Traditional toxicity testing including hydroponic approaches generally neglect rhizospheric effects, which makes it difficult to extrapolate results to real ecosystem processes. To explain the differential effects of sulfide at the different organizational levels, profound knowledge about the biogeochemical, plant physiological and ecological rhizosphere processes is vital. This information is even more important, as anthropogenic inputs of sulfur into freshwater ecosystems and organic loads into freshwater and marine systems are still much higher than natural levels, and are steeply increasing in Asia. In addition, higher temperatures as a result of global climate change may lead to higher sulfide production rates in shallow waters.

  18. Targeting naproxen coupled to human serum albumin to nonparenchymal cells reduces endotoxin-induced mortality in rats with biliary cirrhosis

    NARCIS (Netherlands)

    Albrecht, C.; Meijer, D.K F; Lebbe, C; Sägesser, H; Melgert, B.N; Poelstra, Klaas; Reichen, J

    1997-01-01

    Endotoxin is thought to play a major role in cirrhotic liver disease, Cyclo-oxygenase inhibitors were shown to be partially protective against endotoxin but cannot be used in cirrhotic patients because of renal side-effects, We argued that administration of naproxen (NAP) linked to human serum album

  19. Targeting naproxen coupled to human serum albumin to nonparenchymal cells reduces endotoxin-induced mortality in rats with biliary cirrhosis

    NARCIS (Netherlands)

    Albrecht, C.; Meijer, D.K F; Lebbe, C; Sägesser, H; Melgert, B.N; Poelstra, Klaas; Reichen, J

    1997-01-01

    Endotoxin is thought to play a major role in cirrhotic liver disease, Cyclo-oxygenase inhibitors were shown to be partially protective against endotoxin but cannot be used in cirrhotic patients because of renal side-effects, We argued that administration of naproxen (NAP) linked to human serum

  20. Sulfide response analysis for sulfide control using a pS electrode in sulfate reducing bioreactors.

    Science.gov (United States)

    Villa-Gomez, D K; Cassidy, J; Keesman, K J; Sampaio, R; Lens, P N L

    2014-03-01

    Step changes in the organic loading rate (OLR) through variations in the influent chemical oxygen demand (CODin) concentration or in the hydraulic retention time (HRT) at constant COD/SO4(2-) ratio (0.67) were applied to create sulfide responses for the design of a sulfide control in sulfate reducing bioreactors. The sulfide was measured using a sulfide ion selective electrode (pS) and the values obtained were used to calculate proportional-integral-derivative (PID) controller parameters. The experiments were performed in an inverse fluidized bed bioreactor with automated operation using the LabVIEW software version 2009(®). A rapid response and high sulfide increment was obtained through a stepwise increase in the CODin concentration, while a stepwise decrease to the HRT exhibited a slower response with smaller sulfide increment. Irrespective of the way the OLR was decreased, the pS response showed a time-varying behavior due to sulfide accumulation (HRT change) or utilization of substrate sources that were not accounted for (CODin change). The pS electrode response, however, showed to be informative for applications in sulfate reducing bioreactors. Nevertheless, the recorded pS values need to be corrected for pH variations and high sulfide concentrations (>200 mg/L). Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Sulfide response analysis for sulfide control using a pS electrode in sulfate reducing bioreactors

    NARCIS (Netherlands)

    Villa Gomez, D.K.; Cassidy, J.; Keesman, K.J.; Sampaio, R.M.; Lens, P.N.L.

    2014-01-01

    Step changes in the organic loading rate (OLR) through variations in the influent chemical oxygen demand (CODin) concentration or in the hydraulic retention time (HRT) at constant COD/SO4 2- ratio (0.67) were applied to create sulfide responses for the design of a sulfide control in sulfate reducing

  2. NEAR-CONTINUOUS MEASUREMENT OF HYDROGEN SULFIDE AND CARBONYL SULFIDE BY AN AUTOMATIC GAS CHROMATOGRAPH

    Science.gov (United States)

    An automatic gas chromatograph with a flame photometric detector that samples and analyzes hydrogen sulfide and carbonyl sulfide at 30-s intervals is described. Temperature programming was used to elute trace amounts of carbon disulfide present in each injection from a Supelpak-S...

  3. Hydrogen sulfide induces oxidative damage to RNA and DNA in a sulfide-tolerant marine invertebrate.

    Science.gov (United States)

    Joyner-Matos, Joanna; Predmore, Benjamin L; Stein, Jenny R; Leeuwenburgh, Christiaan; Julian, David

    2010-01-01

    Hydrogen sulfide acts as an environmental toxin across a range of concentrations and as a cellular signaling molecule at very low concentrations. Despite its toxicity, many animals, including the mudflat polychaete Glycera dibranchiata, are periodically or continuously exposed to sulfide in their environment. We tested the hypothesis that a broad range of ecologically relevant sulfide concentrations induces oxidative stress and oxidative damage to RNA and DNA in G. dibranchiata. Coelomocytes exposed in vitro to sulfide (0-3 mmol L(-1) for 1 h) showed dose-dependent increases in oxidative stress (as 2',7'-dichlorofluorescein fluorescence) and superoxide production (as dihydroethidine fluorescence). Coelomocytes exposed in vitro to sulfide (up to 0.73 mmol L(-1) for 2 h) also acquired increased oxidative damage to RNA (detected as 8-oxo-7,8-dihydroguanosine) and DNA (detected as 8-oxo-7,8-dihydro-2'-deoxyguanosine). Worms exposed in vivo to sulfide (0-10 mmol L(-1) for 24 h) acquired elevated oxidative damage to RNA and DNA in both coelomocytes and body wall tissue. While the consequences of RNA and DNA oxidative damage are poorly understood, oxidatively damaged deoxyguanosine bases preferentially bind thymine, causing G-T transversions and potentially causing heritable point mutations. This suggests that sulfide can be an environmental mutagen in sulfide-tolerant invertebrates.

  4. Sulfide response analysis for sulfide control using a pS electrode in sulfate reducing bioreactors

    NARCIS (Netherlands)

    Villa Gomez, D.K.; Cassidy, J.; Keesman, K.J.; Sampaio, R.M.; Lens, P.N.L.

    2014-01-01

    Step changes in the organic loading rate (OLR) through variations in the influent chemical oxygen demand (CODin) concentration or in the hydraulic retention time (HRT) at constant COD/SO4 2- ratio (0.67) were applied to create sulfide responses for the design of a sulfide control in sulfate reducing

  5. Hydrogen sulfide can inhibit and enhance oxygenic photosynthesis in a cyanobacterium from sulfidic springs

    NARCIS (Netherlands)

    Klatt, Judith M.; Haas, Sebastian; Yilmaz, Pelin; de Beer, Dirk; Polerecky, Lubos

    2015-01-01

    We used microsensors to investigate the combinatory effect of hydrogen sulfide (H2S) and light on oxygenic photosynthesis in biofilms formed by a cyanobacterium from sulfidic springs. We found that photosynthesis was both positively and negatively affected by H2S: (i) H2S accelerated the recovery of

  6. Hydrogen sulfide can inhibit and enhance oxygenic photosynthesis in a cyanobacterium from sulfidic springs

    NARCIS (Netherlands)

    Klatt, Judith M.; Haas, Sebastian; Yilmaz, Pelin; de Beer, Dirk; Polerecky, Lubos

    We used microsensors to investigate the combinatory effect of hydrogen sulfide (H2S) and light on oxygenic photosynthesis in biofilms formed by a cyanobacterium from sulfidic springs. We found that photosynthesis was both positively and negatively affected by H2S: (i) H2S accelerated the recovery of

  7. sulfide – reality or fantasy?

    Directory of Open Access Journals (Sweden)

    Paulina Brodek

    2016-08-01

    Full Text Available Hydrogen sulfide (H2S is a signaling gasotransmitter, involved in different physiological and pathological processes. H2S regulates apoptosis, the cell cycle and oxidative stress. H2S exerts powerful effects on smooth muscle cells, endothelial cells, inflammatory cells, endoplasmic reticulum, mitochondria and nuclear transcription factors. H2S is known to be produced from L-cysteine, D-cysteine and L-homocysteine in the body. Four enzymes – cystathionine-b synthase (CBS, mercaptopyruvate sulfurtransferase (3-MST, cystathionine-γ lyase (CSE and cysteine aminotransferase (CAT – are involved in H2S synthesis. The biosynthetic pathway for the production of H2S from D-cysteine involves 3-MST and D-amino acid oxidase (DAO. The therapeutic potential of H2S is not clear. However, recently results have demonstrated that H2S has protective action for ischemic heart disease or hypertension, and protects against ischemia of the brain. This review summarizes the negative and the positive roles of H2S in various biological systems, for example the cardiovascular system and nervous system. We also discuss the function of classical, therapeutic and natural (for example garlic donors of H2S in pre-clinical and clinical studies.

  8. Thermal decomposition of mercuric sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Leckey, J.H.; Nulf, L.E.

    1994-10-28

    The rate of thermal decomposition of mercuric sulfide (HgS) has been measured at temperatures from 265 to 345 C. These data have been analyzed using a first-order chemical reaction model for the time dependence of the reaction and the Arrhenius equation for the temperature dependence of the rate constant. Using this information, the activation energy for the reaction was found to be 55 kcal/mol. Significant reaction vessel surface effects obscured the functional form of the time dependence of the initial portion of the reaction. The data and the resulting time-temperature reaction-rate model were used to predict the decomposition rate of HgS as a function of time and temperature in thermal treatment systems. Data from large-scale thermal treatment studies already completed were interpreted in terms of the results of this study. While the data from the large-scale thermal treatment studies were consistent with the data from this report, mass transport effects may have contributed to the residual amount of mercury which remained in the soil after most of the large-scale runs.

  9. Indium sulfide buffer/CIGSSe interface engineering: Improved cell performance by the addition of zinc sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Allsop, N.A. [Hahn-Meitner-Institut Berlin, Department SE2, Glienicker Str. 100, D-14109 Berlin (Germany)]. E-mail: allsop@hmi.de; Camus, C. [Hahn-Meitner-Institut Berlin, Department SE2, Glienicker Str. 100, D-14109 Berlin (Germany); Haensel, A. [Hahn-Meitner-Institut Berlin, Department SE2, Glienicker Str. 100, D-14109 Berlin (Germany); Gledhill, S.E. [Hahn-Meitner-Institut Berlin, Department SE2, Glienicker Str. 100, D-14109 Berlin (Germany); Lauermann, I. [Hahn-Meitner-Institut Berlin, Department SE2, Glienicker Str. 100, D-14109 Berlin (Germany); Lux-Steiner, M.C. [Hahn-Meitner-Institut Berlin, Department SE2, Glienicker Str. 100, D-14109 Berlin (Germany); Fischer, Ch.-H. [Hahn-Meitner-Institut Berlin, Department SE2, Glienicker Str. 100, D-14109 Berlin (Germany)

    2007-05-31

    Indium sulfide buffer layers deposited by the spray-ion layer gas reaction (Spray-ILGAR) technique are a viable alternative to the traditional cadmium sulfide buffer layer in thin film solar cells. In the present work we report on the results of manipulating the absorber/buffer interface between the chalcopyrite Cu(In,Ga)(S,Se){sub 2} absorber (CIGSSe) and the indium sulfide buffer. It is shown that the deposition of a small amount of zinc sulfide at the absorber/buffer interface can be used to increase the open circuit voltage. A small but significant increase of 20 mV (up to 580 mV), as compared to the pure indium sulfide buffered cells is possible leading to an increase in the overall efficiency.

  10. A study of the stability of cadmium sulfide/copper sulfide and cadmium sulfide copper-indium-diselenide solar cells

    Science.gov (United States)

    Noel, G.; Richard, N.; Gaines, G.

    1984-08-01

    Groups of high efficiency cadmium sulfide/copper sulfide solar cells were exposed to combinations of stresses designed to isolate and accelerate intrinsic degradation mechanisms. Stresses included elevated temperature, illumination intensity, and cell loading conditions. All stress exposures and tests were conducted in a benign (high purity argon) atmosphere. Two primary intrinsic modes of degradation were identified: degradation of the open circuit voltage under continuous illumination and nonzero loading was found to be self recovering upon interruption of illumination or upon shorting or reverse biasing the cells. It was attributed to traps in the depletion region. Recovery from decay of light generated current was not spontaneous but could be partially accomplished by annealing in a reducing (hydrogen) environment. It was attributed to changes in the stoichiometry of the copper sulfide under the influence of electric fields and currents.

  11. Sulfide capacities of fayalite-base slags

    Science.gov (United States)

    Simeonov, S. R.; Sridhar, R.; Toguri, J. M.

    1995-04-01

    The sulfide capacities of fayalite-base slags were measured by a gas-slag equilibration technique under controlled oxygen and sulfur potentials similar to those encountered in the pyrometallurgical processing of nonferrous metals. The oxygen pressure range was from 10-9.5 to 10-11 MPa and the sulfur pressure range from 10-3 to 10-4.5 MPa, over a temperature range of 1473 to 1623 K. The slags studied were FeO-SiO2 at silica saturation and those with addition of CaO, MgO, and Al2O3 to determine their effect on sulfide capacities. For these slags, the sulfide capacities were found to vary from 10-3.3 to 10-5. The sulfide capacities increased with increasing temperature from 1473 to 1623 K. A comparison of the reported plant data on sulfur content of industrial slags shows good agreement with the present experimental results. The present data will be useful in estimating metal losses in slag due to metal sulfide entrainment in nonferrous smelters.

  12. Hydrogen sulfide: neurochemistry and neurobiology.

    Science.gov (United States)

    Qu, K; Lee, S W; Bian, J S; Low, C-M; Wong, P T-H

    2008-01-01

    Current evidence suggests that hydrogen sulfide (H2S) plays an important role in brain functions, probably acting as a neuromodulator as well as an intracellular messenger. In the mammalian CNS, H2S is formed from the amino acid cysteine by the action of cystathionine beta-synthase (CBS) with serine (Ser) as the by-product. As CBS is a calcium and calmodulin dependent enzyme, the biosynthesis of H2S should be acutely controlled by the intracellular concentration of calcium. In addition, it is also regulated by S-adenosylmethionine which acts as an allosteric activator of CBS. H2S, as a sulfhydryl compound, has similar reducing properties as glutathione. In neurons, H2S stimulates the production of cAMP probably by direct activation of adenylyl cyclase and thus activate cAMP-dependent processes. In astrocytes, H2S increases intracellular calcium to an extent capable of inducing and propagating a "calcium wave", which is a form of calcium signaling among these cells. Possible physiological functions of H2S include potentiating long-term potentials through activation of the NMDA receptors, regulating the redox status, maintaining the excitatory/inhibitory balance in neurotransmission, and inhibiting oxidative damage through scavenging free radicals and reactive species. H2S is also involved in CNS pathologies such as stroke and Alzheimer's disease. In stroke, H2S appears to act as a mediator of ischemic injuries and thus inhibition of its production has been suggested to be a potential treatment approach in stroke therapy.

  13. Effect of Sulindac Binary System on In Vitro and In Vivo Release Profiles: An Assessment of Polymer Type and Its Ratio

    Science.gov (United States)

    2016-01-01

    The bioavailability of sulindac (SDC), a nonsteroidal anti-inflammatory drug, is low due to poor aqueous solubility and poor dissolution rate. For this reason it is necessary to enhance the solubility and enhance dissolution of the drug by dispersing SDC in polyethylene glycols 6000 (PEG 6000) and polyvinyl pyrrolidone 40000 (PVP 40000) matrices using the coevaporation technique. Studying the influence of SDC to polymer ratio on drug content, percent yield, particle size, and in vitro release was performed. Differential scanning calorimetry, X-ray diffraction, and scanning electron microscopy were used to characterize any change in crystal habit of SDC in the prepared formulae. The anti-inflammatory effect of SDC was studied using the hind paw edema model. It was found that incorporation of SDC in PEG 6000 and PVP 40000 matrices resulted in improving the dissolution rate, which was found to depend on the polymer and its weight ratio of the drug. It is clearly obvious that the dissolution rate was remarkably improved in drug PVP 40000 molecular dispersions when compared to drug PEG 6000 systems. Solid dispersion of SDC in PEG and PVP improved the anti-inflammatory effect of SDC and it was found that formula SDV5 exhibited a more pronounced inhibition of swelling than other formulae. PMID:27840824

  14. Effect of Sulindac Binary System on In Vitro and In Vivo Release Profiles: An Assessment of Polymer Type and Its Ratio

    Directory of Open Access Journals (Sweden)

    Gamal A. Shazly

    2016-01-01

    Full Text Available The bioavailability of sulindac (SDC, a nonsteroidal anti-inflammatory drug, is low due to poor aqueous solubility and poor dissolution rate. For this reason it is necessary to enhance the solubility and enhance dissolution of the drug by dispersing SDC in polyethylene glycols 6000 (PEG 6000 and polyvinyl pyrrolidone 40000 (PVP 40000 matrices using the coevaporation technique. Studying the influence of SDC to polymer ratio on drug content, percent yield, particle size, and in vitro release was performed. Differential scanning calorimetry, X-ray diffraction, and scanning electron microscopy were used to characterize any change in crystal habit of SDC in the prepared formulae. The anti-inflammatory effect of SDC was studied using the hind paw edema model. It was found that incorporation of SDC in PEG 6000 and PVP 40000 matrices resulted in improving the dissolution rate, which was found to depend on the polymer and its weight ratio of the drug. It is clearly obvious that the dissolution rate was remarkably improved in drug PVP 40000 molecular dispersions when compared to drug PEG 6000 systems. Solid dispersion of SDC in PEG and PVP improved the anti-inflammatory effect of SDC and it was found that formula SDV5 exhibited a more pronounced inhibition of swelling than other formulae.

  15. Solar thermal extraction of copper from sulfides

    Energy Technology Data Exchange (ETDEWEB)

    Winkel, L.; Guesdon, C.; Sturzenegger, M.

    2003-03-01

    With the aim to develop a solar-driven process for the extraction of copper from sulfide concentrates re-search on the decomposition of copper sulfides under inert atmospheres has been initiated. Thermogravimetric measurements on chalcocite (Cu{sub 2}S) revealed that copper is formed already at 1823 K. Chalcopyrite (CuFeS{sub 2}) also disintegrates at this temperature, although at a lower rate. Copper and iron have been identified in the solid residue. The results confirm the feasibility of copper extraction by direct decomposition of sulfides under atmospheric pressure. The decomposition under inert atmosphere prevents generation of SO{sub 2}, and is beneficial to the removal of volatile impurities. Chemical equilibrium calculations for CuFeS{sub 2} contaminated with enargite (Cu{sub 3}AsS{sub 4}) have shown that the absence of an oxidic slag allows for a complete evaporation of arsenic and subsequent separation. (author)

  16. Sulfide and methane production in sewer sediments.

    Science.gov (United States)

    Liu, Yiwen; Ni, Bing-Jie; Ganigué, Ramon; Werner, Ursula; Sharma, Keshab R; Yuan, Zhiguo

    2015-03-01

    Recent studies have demonstrated significant sulfide and methane production by sewer biofilms, particularly in rising mains. Sewer sediments in gravity sewers are also biologically active; however, their contribution to biological transformations in sewers is poorly understood at present. In this study, sediments collected from a gravity sewer were cultivated in a laboratory reactor fed with real wastewater for more than one year to obtain intact sediments. Batch test results show significant sulfide production with an average rate of 9.20 ± 0.39 g S/m(2)·d from the sediments, which is significantly higher than the areal rate of sewer biofilms. In contrast, the average methane production rate is 1.56 ± 0.14 g CH4/m(2)·d at 20 °C, which is comparable to the areal rate of sewer biofilms. These results clearly show that the contributions of sewer sediments to sulfide and methane production cannot be ignored when evaluating sewer emissions. Microsensor and pore water measurements of sulfide, sulfate and methane in the sediments, microbial profiling along the depth of the sediments and mathematical modelling reveal that sulfide production takes place near the sediment surface due to the limited penetration of sulfate. In comparison, methane production occurs in a much deeper zone below the surface likely due to the better penetration of soluble organic carbon. Modelling results illustrate the dependency of sulfide and methane productions on the bulk sulfate and soluble organic carbon concentrations can be well described with half-order kinetics.

  17. Membrane for hydrogen recovery from streams containing hydrogen sulfide

    Science.gov (United States)

    Agarwal, Pradeep K.

    2007-01-16

    A membrane for hydrogen recovery from streams containing hydrogen sulfide is provided. The membrane comprises a substrate, a hydrogen permeable first membrane layer deposited on the substrate, and a second membrane layer deposited on the first layer. The second layer contains sulfides of transition metals and positioned on the on a feed side of the hydrogen sulfide stream. The present invention also includes a method for the direct decomposition of hydrogen sulfide to hydrogen and sulfur.

  18. Acute inhalation toxicity of carbonyl sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Benson, J.M.; Hahn, F.F.; Barr, E.B. [and others

    1995-12-01

    Carbonyl sulfide (COS), a colorless gas, is a side product of industrial procedures sure as coal hydrogenation and gasification. It is structurally related to and is a metabolite of carbon disulfide. COS is metabolized in the body by carbonic anhydrase to hydrogen sulfide (H{sub 2}S), which is thought to be responsible for COS toxicity. No threshold limit value for COS has been established. Results of these studies indicate COS (with an LC{sub 50} of 590 ppm) is slightly less acutely toxic than H{sub 2}S (LC{sub 50} of 440 ppm).

  19. Modeling of Sulfide Microenvironments on Mars

    Science.gov (United States)

    Schwenzer, S. P.; Bridges, J. C.; McAdam, A.; Steer, E. D.; Conrad, P. G.; Kelley, S. P.; Wiens, R. C.; Mangold, N.; Grotzinger, J.; Eigenbrode, J. L.; Franz, H. B.; Sutter, B.

    2016-01-01

    Yellowknife Bay (YKB; sol 124-198) is the second site that the Mars Science Laboratory Rover Curiosity investigated in detail on its mission in Gale Crater. YKB represents lake bed sediments from an overall neutral pH, low salinity environment, with a mineralogical composition which includes Ca-sulfates, Fe oxide/hydroxides, Fe-sulfides, amorphous material, and trioctahedral phyllosilicates. We investigate whether sulfide alteration could be associated with ancient habitable microenvironments in the Gale mudstones. Some textural evidence for such alteration may be pre-sent in the nodules present in the mudstone.

  20. Iron-sulfide crystals in probe deposits

    DEFF Research Database (Denmark)

    Laursen, Karin; Frandsen, Flemming

    1998-01-01

    Iron-sulfides were observed in deposits collected on a probe inserted at the top of the furnace of a coal-fired power station in Denmark. The chemical composition of the iron-sulfides is equivalent to pyrrhotite (FeS). The pyrrhotites are present as crystals and, based on the shape of the crystals......, it was deduced that they were not deposited but instead grew within the deposit. The presence of unburned char particles within the deposits supports the concept that a reducing environment existed in the deposits. Two processes are proposed for explaining the existence of pyrrhotite crystals within a deposit...

  1. Use of biogenic sulfide for ZnS precipitation

    NARCIS (Netherlands)

    Esposito, G.; Veeken, A.; Weijma, J.; Lens, P.N.L.

    2006-01-01

    A 600 ml continuously stirred tank reactor was used to assess the performance of a zinc sulfide precipitation process using a biogenic sulfide solution (the effluent of a sulfate-reducing bioreactor) as sulfide source. In all experiments, a proportional-integral (PI) control algorithm was used to co

  2. A physiologically based kinetic model for bacterial sulfide oxidation

    NARCIS (Netherlands)

    Klok, J.B.; Graaff, M. de; Bosch, P.L. van den; Boelee, N.C.; Keesman, K.J.; Janssen, A.J.W.M.

    2013-01-01

    In the biotechnological process for hydrogen sulfide removal from gas streams, a variety of oxidation products can be formed. Under natron-alkaline conditions, sulfide is oxidized by haloalkaliphilic sulfide oxidizing bacteria via flavocytochrome c oxidoreductase. From previous studies, it was concl

  3. Measurement and biological significance of the volatile sulfur compounds hydrogen sulfide, methanethiol and dimethyl sulfide in various biological matrices.

    NARCIS (Netherlands)

    Tangerman, A.

    2009-01-01

    This review deals with the measurement of the volatile sulfur compounds hydrogen sulfide, methanethiol and dimethyl sulfide in various biological matrices of rats and humans (blood, serum, tissues, urine, breath, feces and flatus). Hydrogen sulfide and methanethiol both contain the active thiol (-SH

  4. Measurement and biological significance of the volatile sulfur compounds hydrogen sulfide, methanethiol and dimethyl sulfide in various biological matrices

    NARCIS (Netherlands)

    Tangerman, Albert

    2009-01-01

    This review deals with the measurement of the volatile Sulfur compounds hydrogen sulfide, methanethiol and dimethyl sulfide in various biological matrices of rats and humans (blood, serum, tissues, urine, breath, feces and flatus). Hydrogen sulfide and methanethiol both contain the active thiol (-SH

  5. Measurement and biological significance of the volatile sulfur compounds hydrogen sulfide, methanethiol and dimethyl sulfide in various biological matrices

    NARCIS (Netherlands)

    Tangerman, Albert

    2009-01-01

    This review deals with the measurement of the volatile Sulfur compounds hydrogen sulfide, methanethiol and dimethyl sulfide in various biological matrices of rats and humans (blood, serum, tissues, urine, breath, feces and flatus). Hydrogen sulfide and methanethiol both contain the active thiol

  6. Measurement and biological significance of the volatile sulfur compounds hydrogen sulfide, methanethiol and dimethyl sulfide in various biological matrices.

    NARCIS (Netherlands)

    Tangerman, A.

    2009-01-01

    This review deals with the measurement of the volatile sulfur compounds hydrogen sulfide, methanethiol and dimethyl sulfide in various biological matrices of rats and humans (blood, serum, tissues, urine, breath, feces and flatus). Hydrogen sulfide and methanethiol both contain the active thiol

  7. Modeling Sulfides, pH and Hydrogen Sulfide Gas in the Sewers of San Francisco

    DEFF Research Database (Denmark)

    Vollertsen, Jes; Revilla, Nohemy; Hvitved-Jacobsen, Thorkild

    2015-01-01

    An extensive measuring campaign targeted on sewer odor problems was undertaken in San Francisco. It was assessed whether a conceptual sewer process model could reproduce the measured concentrations of total sulfide in the wastewater and H2S gas in the sewer atmosphere, and to which degree...... such simulations have potential for further improving odor and sulfide management. The campaign covered measurement of wastewater sulfide by grab sampling and diurnal sampling, and H2S gas in the sewer atmosphere was logged. The tested model was based on the Wastewater Aerobic/Anaerobic Transformations in Sewers...... (WATS) sewer process concept, which never had been calibrated to such an extensive dataset. The study showed that the model was capable of reproducing the general levels of wastewater sulfide, wastewater pH, and sewer H2S gas. It could also reproduce the general variability of these parameters, albeit...

  8. Monitoring sulfide and sulfate-reducing bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Tanner, R.S.

    1995-12-31

    Simple yet precise and accurate methods for monitoring sulfate-reducing bacteria (SRB) and sulfide remain useful for the study of bacterial souring and corrosion. Test kits are available to measure sulfide in field samples. A more precise methylene blue sulfide assay for both field and laboratory studies is described here. Improved media, compared to that in API RP-38, for enumeration of SRB have been formulated. One of these, API-RST, contained cysteine (1.1 mM) as a reducing agent, which may be a confounding source of sulfide. While cysteine was required for rapid enumeration of SRB from environmental samples, the concentration of cysteine in medium could be reduced to 0.4 mM. It was also determined that elevated levels of yeast extract (>1 g/liter) could interfere with enumeration of SRB from environmental samples. The API-RST medium was modified to a RST-11 medium. Other changes in medium composition, in addition to reduction of cysteine, included reduction of the concentration of phosphate from 3.4 mM to 2.2 mM, reduction of the concentration of ferrous iron from 0.8 mM to 0.5 mM and preparation of a stock mineral solution to ease medium preparation. SRB from environmental samples could be enumerated in a week in this medium.

  9. Platinum metals in magmatic sulfide ores

    Science.gov (United States)

    Naldrett, A.J.; Duke, J.M.

    1980-01-01

    Platinum-group elements (PGE) are mined predominantly from deposits that have formed by the segregation of molten iron-nickel-copper sulfides from silicate magmas. The absolute concentrations of PGE in sulfides from different deposits vary over a range of five orders of magnitude, whereas those of other chalcophile elements vary by factors of only 2 to 100. However, the relative proportions of the different PGE in a given deposit are systematically related to the nature of the parent magma. The absolute and relative concentrations of PGE in magmatic sulfides are explained in terms of the degree of partial melting of mantle peridotite required to produce the parent magma and the processes of batch equilibration and fractional segregation of sulfides. The Republic of South Africa and the U.S.S.R. together possess more than 97 percent of the world PGE reserves, but significant undeveloped resources occur in North America. The Stillwater complex in Montana is perhaps the most important example. Copyright ?? 1980 AAAS.

  10. Hydrogen Sulfide in Preeclampsia : Potential Therapeutic Implications

    NARCIS (Netherlands)

    Holwerda, Kim

    2015-01-01

    The thesis provide insights into the production and possible therapeutic effect of the gaseous molecule hydrogen sulfide (H2S) in preeclampsia (PE). H2S is an important molecule in the (human) body. It is among others involved in blood pressure regulation, stimulation of vascular growth and

  11. Nucleation of mercury sulfide by dealkylation

    Science.gov (United States)

    Enescu, Mironel; Nagy, Kathryn L.; Manceau, Alain

    2016-12-01

    Metal sulfide minerals are assumed to form naturally at ambient conditions via reaction of a metallic element with (poly)sulfide ions, usually produced by microbes in oxygen-depleted environments. Recently, the formation of mercury sulfide (β-HgS) directly from linear Hg(II)-thiolate complexes (Hg(SR)2) in natural organic matter and in cysteine solutions was demonstrated under aerated conditions. Here, a detailed description of this non-sulfidic reaction is provided by computations at a high level of molecular-orbital theory. The HgS stoichiometry is obtained through the cleavage of the S-C bond in one thiolate, transfer of the resulting alkyl group (R’) to another thiolate, and subsequent elimination of a sulfur atom from the second thiolate as a thioether (RSR’). Repetition of this mechanism leads to the formation of RS-(HgS)n-R chains which may self-assemble in parallel arrays to form cinnabar (α-HgS), or more commonly, quickly condense to four-coordinate metacinnabar (β-HgS). The mechanistic pathway is thermodynamically favorable and its predicted kinetics agrees with experiment. The results provide robust theoretical support for the abiotic natural formation of nanoparticulate HgS under oxic conditions and in the absence of a catalyst, and suggest a new route for the (bio)synthesis of HgS nanoparticles with improved technological properties.

  12. 30 CFR 250.490 - Hydrogen sulfide.

    Science.gov (United States)

    2010-07-01

    ... been confirmed. Well-control fluid means drilling mud and completion or workover fluid as appropriate... OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Hydrogen Sulfide § 250.490 Hydrogen... section when conducting drilling, well-completion/well-workover, and production operations in zones...

  13. Microaeration reduces hydrogen sulfide in biogas

    Science.gov (United States)

    Although there are a variety of biological and chemical treatments for removal of hydrogen sulfide (H2S) from biogas, all require some level of chemical or water inputs and maintenance. In practice, managing biogas H2S remains a significant challenge for agricultural digesters where labor and opera...

  14. Microbial Fuel Cells for Sulfide Removal

    NARCIS (Netherlands)

    Rabaey, K.; Sompel, van de S.; Maignien, L.; Boon, N.; Aelterman, P.; Clauwaert, P.; Schamphelaire, de L.; The Pham, H.; Vermeulen, J.; Verhaege, M.; Lens, P.N.L.; Verstraete, W.

    2006-01-01

    Thus far, microbial fuel cells (MFCs) have been used to convert carbon-based substrates to electricity. However, sulfur compounds are ubiquitously present in organic waste and wastewater. In this study, a MFC with a hexacyanoferrate cathodic electrolyte was used to convert dissolved sulfide to eleme

  15. Acid volatile sulfide (AVS)- a comment

    NARCIS (Netherlands)

    Meysman, F.J.R.; Middelburg, J.J.

    2005-01-01

    The review by Rickard and Morse (this volume) adequately summarizes our current understanding with respect to acid-volatile sulfides (AVS). At the same time, this review addresses some of the misunderstandings with regard to measurements and dynamics of this important sedimentary sulfur pool. In

  16. Comparison of Hydrogen Sulfide Analysis Techniques

    Science.gov (United States)

    Bethea, Robert M.

    1973-01-01

    A summary and critique of common methods of hydrogen sulfide analysis is presented. Procedures described are: reflectance from silver plates and lead acetate-coated tiles, lead acetate and mercuric chloride paper tapes, sodium nitroprusside and methylene blue wet chemical methods, infrared spectrophotometry, and gas chromatography. (BL)

  17. Hydrogen Sulfide in Preeclampsia : Potential Therapeutic Implications

    NARCIS (Netherlands)

    Holwerda, Kim

    2015-01-01

    The thesis provide insights into the production and possible therapeutic effect of the gaseous molecule hydrogen sulfide (H2S) in preeclampsia (PE). H2S is an important molecule in the (human) body. It is among others involved in blood pressure regulation, stimulation of vascular growth and modulati

  18. Sulfide Precipitation in Wastewater at Short Timescales

    DEFF Research Database (Denmark)

    Kiilerich, Bruno; van de Ven, Wilbert; Nielsen, Asbjørn Haaning

    2017-01-01

    that this is not the case for sulfide precipitation by ferric iron. Instead, the reaction time was found to be on a timescale where it must be considered when performing end-of-pipe treatment. For real wastewaters at pH 7, a stoichiometric ratio around 14 mol Fe(II) (mol S(−II))−1 was obtained after 1.5 s, while the ratio......Abatement of sulfides in sewer systems using iron salts is a widely used strategy. When dosing at the end of a pumping main, the reaction kinetics of sulfide precipitation becomes important. Traditionally the reaction has been assumed to be rapid or even instantaneous. This work shows...... dropped to about 5 mol Fe(II) (mol S(−II))−1 after 30 s. Equilibrium calculations yielded a theoretic ratio of 2 mol Fe(II) (mol S(−II))−1, indicating that the process had not equilibrated within the span of the experiment. Correspondingly, the highest sulfide conversion only reached 60%. These findings...

  19. Oxidation and Precipitation of Sulfide in Sewer Networks

    DEFF Research Database (Denmark)

    Nielsen, A. H.

    were studied in both wastewater and biofilms. Particular emphasis was on the importance of iron in the sulfur cycle. Iron is typically among the dominant metals in wastewater. The experiments showed that, ferric iron (Fe(III)) that was added to anaerobic wastewater was rapidly reduced to ferrous iron...... (Fe(II)) and precipitated subsequently with dissolved sulfide as ferrous sulfide (FeS). The ferrous sulfide precipitation was relatively fast, but not immediate. Despite the very low solubility of ferrous sulfide, initially present iron did not react completely with sulfide. This observation...

  20. Sulfide removal by moderate oxygenation of anaerobic sludge environments

    Energy Technology Data Exchange (ETDEWEB)

    Van der Zee, F.P.; Villaverde, S.; Polanco, F. [Valladolid Univ., Valladolid (Spain). Dept. of Chemical Engineering; Garcia, P.A.

    2004-07-01

    Treating wastewater through anaerobic bioreactors results in the formation of hydrogen sulfide. The sulfide can be removed from the biogas by introducing air directly into the anaerobic bioreactor system. This study presents the results of batch experiments that provided a better insight into the fate of sulfur compounds and oxygen during microaerobic sulfide oxidation in granular sludge. It was shown that sulfide could be removed rapidly upon introduction of low amounts of oxygen to the sulfide-amended batch vials with granular sludge treating vinasse. Initially, the sulfide was oxidized to elemental sulfur, thiosulfate and polysulfide. Significant production of sulfate did not occur. The introduction of oxygen, however, could result in the growth of aerobic organic-chemical oxygen demand-oxidizing bacteria that compete with sulfide oxidation for oxygen. 6 refs., 1 tab., 1 fig.

  1. Sulfide, the first inorganic substrate for human cells.

    Science.gov (United States)

    Goubern, Marc; Andriamihaja, Mireille; Nübel, Tobias; Blachier, François; Bouillaud, Frédéric

    2007-06-01

    Hydrogen sulfide (H2S) is produced inside the intestine and is known as a poison that inhibits cellular respiration at the level of cytochrome oxidase. However, sulfide is used as an energetic substrate by many photo- and chemoautotrophic bacteria and by animals such as the lugworm Arenicola marina. The concentrations of sulfide present in their habitats are comparable with those present in the human colon. Using permeabilized colonic cells to which sulfide was added by an infusion pump we show that the maximal respiratory rate of colonocyte mitochondria in presence of sulfide compares with that obtained with succinate or L-alpha-glycerophosphate. This oxidation is accompanied by mitochondrial energization. In contrast, other cell types not naturally exposed to high concentration of sulfide showed much lower oxidation rates. Mitochondria showed a very high affinity for sulfide that permits its use as an energetic substrate at low micromolar concentrations, hence, below the toxic level. However, if the supply of sulfide exceeds the oxidation rate, poisoning renders mitochondria inefficient and our data suggest that an anaerobic mechanism involving partial reversion of Krebs cycle already known in invertebrates takes place. In conclusion, this work provides additional and compelling evidence that sulfide is not only a toxic compound. According to our study, sulfide appears to be the first inorganic substrate for mammalian cells characterized thus far.

  2. The Evolution of Sulfide Tolerance in the Cyanobacteria

    Science.gov (United States)

    Miller, Scott R.; Bebout, Brad M.; DeVincenzi, Donald L. (Technical Monitor)

    2000-01-01

    Understanding how the function of extant microorganisms has recorded both their evolutionary histories and their past interactions with the environment is a stated goal of astrobiology. We are taking a multidisciplinary approach to investigate the diversification of sulfide tolerance mechanisms in the cyanobacteria, which vary both in their degree of exposure to sulfide and in their capacity to tolerate this inhibitor of photosynthetic electron transport. Since conditions were very reducing during the first part of Earth's history and detrital sulfides have been found in Archean sediments, mechanisms conferring sulfide tolerance may have been important for the evolutionary success of the ancestors of extant cyanobacteria. Two tolerance mechanisms have been identified in this group: (1) resistance of photosystem II, the principal target of sulfide toxicity; and (2) maintenance of the ability to fix carbon despite photosystem II inhibition by utilizing sulfide as an electron donor in photosystem I - dependent, anoxygenic photosynthesis. We are presently collecting comparative data on aspects of sulfide physiology for laboratory clones isolated from a variety of habitats. These data will be analyzed within a phylogenetic framework inferred from molecular sequence data collected for these clones to test how frequently different mechanisms of tolerance have evolved and which tolerance mechanism evolved first. In addition, by analyzing these physiological data together with environmental sulfide data collected from our research sites using microelectrodes, we can also test whether the breadth of an organism's sulfide tolerance can be predicted from the magnitude of variation in environmental sulfide concentration it has experienced in its recent evolutionary past and whether greater average sulfide concentration and/or temporal variability in sulfide favors the evolution of a particular mechanism of sulfide tolerance.

  3. Iron-sulfide redox flow batteries

    Science.gov (United States)

    Xia, Guan-Guang; Yang, Zhenguo; Li, Liyu; Kim, Soowhan; Liu, Jun; Graff, Gordon L

    2013-12-17

    Iron-sulfide redox flow battery (RFB) systems can be advantageous for energy storage, particularly when the electrolytes have pH values greater than 6. Such systems can exhibit excellent energy conversion efficiency and stability and can utilize low-cost materials that are relatively safer and more environmentally friendly. One example of an iron-sulfide RFB is characterized by a positive electrolyte that comprises Fe(III) and/or Fe(II) in a positive electrolyte supporting solution, a negative electrolyte that comprises S.sup.2- and/or S in a negative electrolyte supporting solution, and a membrane, or a separator, that separates the positive electrolyte and electrode from the negative electrolyte and electrode.

  4. Oxidation of Reduced Sulfur Species: Carbonyl Sulfide

    DEFF Research Database (Denmark)

    Glarborg, Peter; Marshall, Paul

    2013-01-01

    A detailed chemical kinetic model for oxidation of carbonyl sulfide (OCS) has been developed, based on a critical evaluation of data from the literature. The mechanism has been validated against experimental results from batch reactors, flow reactors, and shock tubes. The model predicts satisfact......A detailed chemical kinetic model for oxidation of carbonyl sulfide (OCS) has been developed, based on a critical evaluation of data from the literature. The mechanism has been validated against experimental results from batch reactors, flow reactors, and shock tubes. The model predicts...... by the competition between chain‐branching and ‐propagating steps; modeling predictions are particularly sensitive to the branching fraction for the OCS + O reaction to form CO + SO or CO2 + S....

  5. Speciation of arsenic in sulfidic waters

    Directory of Open Access Journals (Sweden)

    Ford Robert G

    2003-03-01

    Full Text Available Formation constants for thioarsenite species have been determined in dilute solutions at 25°C, ΣH2S from 10-7.5 to 10-3.0 M, ΣAs from 10-5.6 to 10-4.8 M, and pH 7 and 10. The principal inorganic arsenic species in anoxic aquatic systems are arsenite, As(OH30, and a mononuclear thioarsenite with an S/As ratio of 3:1. Thioarsenic species with S/As ratios of 1 : 1,2 : 1, and 4 : 1 are lesser components in sulfidic solutions that might be encountered in natural aquatic environments. Thioarsenites dominate arsenic speciation at sulfide concentrations > 10-4.3 M at neutral pH. Conversion from neutral As(OH30 to anionic thioarsenite species may regulate the transport and fate of arsenic in sulfate-reducing environments by governing sorption and mineral precipitation reactions.

  6. Iron-sulfide redox flow batteries

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Guanguang; Yang, Zhenguo; Li, Liyu; Kim, Soowhan; Liu, Jun; Graff, Gordon L

    2016-06-14

    Iron-sulfide redox flow battery (RFB) systems can be advantageous for energy storage, particularly when the electrolytes have pH values greater than 6. Such systems can exhibit excellent energy conversion efficiency and stability and can utilize low-cost materials that are relatively safer and more environmentally friendly. One example of an iron-sulfide RFB is characterized by a positive electrolyte that comprises Fe(III) and/or Fe(II) in a positive electrolyte supporting solution, a negative electrolyte that comprises S.sup.2- and/or S in a negative electrolyte supporting solution, and a membrane, or a separator, that separates the positive electrolyte and electrode from the negative electrolyte and electrode.

  7. Subsurface heaters with low sulfidation rates

    Energy Technology Data Exchange (ETDEWEB)

    John, Randy Carl; Vinegar, Harold J

    2013-12-10

    A system for heating a hydrocarbon containing formation includes a heater having an elongated ferromagnetic metal heater section. The heater is located in an opening in a formation. The heater section is configured to heat the hydrocarbon containing formation. The exposed ferromagnetic metal has a sulfidation rate that goes down with increasing temperature of the heater, when the heater is in a selected temperature range.

  8. Hydrogen sulfide prodrugs—a review

    Directory of Open Access Journals (Sweden)

    Yueqin Zheng

    2015-09-01

    Full Text Available Hydrogen sulfide (H2S is recognized as one of three gasotransmitters together with nitric oxide (NO and carbon monoxide (CO. As a signaling molecule, H2S plays an important role in physiology and shows great potential in pharmaceutical applications. Along this line, there is a need for the development of H2S prodrugs for various reasons. In this review, we summarize different H2S prodrugs, their chemical properties, and some of their potential therapeutic applications.

  9. Hydrogen sulfide prodrugs—a review

    Science.gov (United States)

    Zheng, Yueqin; Ji, Xingyue; Ji, Kaili; Wang, Binghe

    2015-01-01

    Hydrogen sulfide (H2S) is recognized as one of three gasotransmitters together with nitric oxide (NO) and carbon monoxide (CO). As a signaling molecule, H2S plays an important role in physiology and shows great potential in pharmaceutical applications. Along this line, there is a need for the development of H2S prodrugs for various reasons. In this review, we summarize different H2S prodrugs, their chemical properties, and some of their potential therapeutic applications. PMID:26579468

  10. Redetermination of piperidinium hydrogen sulfide structure

    Science.gov (United States)

    Andras, Maria T.; Hepp, Aloysius F.; Fanwick, Phillip E.; Duraj, Stan A.; Gordon, Edward M.

    1994-01-01

    The presence of adventitious water in a reaction between dicyclopentamethylene thiuram-disulfide (C5H10NCS2)(sub 2) and a picoline solution of tricyclopentadienyl indium(III) (C5H5)(sub 3). It resulted in the formation of piperidinium hydrogen sulfide (C5H13NS). The piperidinium hydrogen sulfide produced in this way was unambiguously characterized by X-ray crystallography. The structure determination showed that the piperidinium hydrogen sulfide crystal (MW = 119.23 g/mol) has an orthorhombic (Pbcm) unit cell whose parameters are: a = 9.818(2), b = 7.3720(1), c = 9.754(1) A, V = 706.0(3) A(exp 3), Z=4. D(sub chi) = 1.122 g cm(exp -3), Mo K(alpha) (lamda = 0.71073), mu= 3.36 cm(exp -1), F(000) = 264.0, T =293 K, R = 0.036 for 343 reflections with F(sub O)(sup 2) greater than 3 sigma (F(sub O)(sup 2)) and 65 variables. The compound consists of (C5H10NH2)(+) cations and (SH)(-) anions with both species residing on crystallographic mirror planes. N-H -- S hydrogen bonding contributes to the interconnection of neighboring piperidinium components of the compound.

  11. Air-water transfer of hydrogen sulfide

    DEFF Research Database (Denmark)

    Yongsiri, C.; Vollertsen, J.; Rasmussen, M. R.

    2004-01-01

    experiments. By means of the overall mass–transfer coefficient (KLa), the transfer coefficient of hydrogen sulfide (KLaH2S), referring to total sulfide, was correlated to that of oxygen (KLaO2) (i.e., the reaeration coefficient). Results demonstrate that both turbulence and pH in the water phase play...... a significant role for KLaH2S. An exponential expression is a suitable representation for the relationship between KLaH2S and the Froude number at all pH values studied (4.5 to 8.0). Because of the dissociation of hydrogen sulfide, KLaH2S increased with decreasing pH at a constant turbulence level. Relative...... differences in KLaH2S at pH values between 4.5 and 8.0 became larger as the turbulence level increased, whereas those at pH between 4.5 and 7.0 did not statistically show any change. At constant pH, KLaH2S/KLaO2 was observed not to be dependent on the turbulence range studied. KLaH2S/KLaO2 ratio was 0...

  12. Organization of the human mitochondrial hydrogen sulfide oxidation pathway.

    Science.gov (United States)

    Libiad, Marouane; Yadav, Pramod Kumar; Vitvitsky, Victor; Martinov, Michael; Banerjee, Ruma

    2014-11-07

    Sulfide oxidation is expected to play an important role in cellular switching between low steady-state intracellular hydrogen sulfide levels and the higher concentrations where the physiological effects are elicited. Yet despite its significance, fundamental questions regarding how the sulfide oxidation pathway is wired remain unanswered, and competing proposals exist that diverge at the very first step catalyzed by sulfide quinone oxidoreductase (SQR). We demonstrate that, in addition to sulfite, glutathione functions as a persulfide acceptor for human SQR and that rhodanese preferentially synthesizes rather than utilizes thiosulfate. The kinetic behavior of these enzymes provides compelling evidence for the flow of sulfide via SQR to glutathione persulfide, which is then partitioned to thiosulfate or sulfite. Kinetic simulations at physiologically relevant metabolite concentrations provide additional support for the organizational logic of the sulfide oxidation pathway in which glutathione persulfide is the first intermediate formed.

  13. Sulfide scaling in low enthalpy geothermal environments; A survey

    Energy Technology Data Exchange (ETDEWEB)

    Criaud, A.; Fouillac, C. (Bureau de Recherches Geologiques et Minieres (BRGM), 45 - Orleans (France))

    1989-01-01

    A review of the sulfide scaling phenomena in low-temperature environments is presented. While high-temperature fluids tend to deposit metal sulfides because of their high concentrations of dissolved metals and variations of temperature, pressure and fluid chemistry, low temperature media are characterized by very low metal content but much higher dissolved sulfide. In the case of the goethermal wells of the Paris Basin, detailed studies demonstrate that the relatively large concentrations of chloride and dissolved sulfide are responsible for corrosion and consequent formation of iron sulfide scale composed of mackinawite, pyrite and pyrrhotite. The effects of the exploitation schemes are far less important than the corrosion of the casings. The low-enthalpy fluids that do not originate from sedimentary aquifers (such as in Iceland and Bulgaria), have a limited corrosion potential, and the thin sulfide film that appears may prevent the progress of corrosion.

  14. Measurement of plasma hydrogen sulfide in vivo and in vitro

    OpenAIRE

    Shen, Xinggui; Pattillo, Christopher B.; Pardue, Sibile; Bir, Shyamal C.; Wang, Rui; Kevil, Christopher G.

    2011-01-01

    The gasotransmitter hydrogen sulfide is known to regulate multiple cellular functions during normal and pathophysiological states. However, a paucity of concise information exists regarding quantitative amounts of hydrogen sulfide involved in physiological and pathological responses. This is primarily due to disagreement among various methods employed to measure free hydrogen sulfide. In this article, we describe a very sensitive method of measuring the presence of H2S in plasma down to nanom...

  15. Limitation of Sulfide Capacity Concept for Molten Slags

    Science.gov (United States)

    Jung, In-Ho; Moosavi-Khoonsari, Elmira

    2016-04-01

    The sulfide capacity concept has been widely used in pyrometallurgy to define sulfur removal capacities of slags. Typically, the sulfide capacity is considered to be a unique slag property depending only on temperature regardless of partial pressures of oxygen and sulfur. In the present study, it is demonstrated that sulfide capacities of slags in particular those of Na2O-containing slags can vary with partial pressures of oxygen and sulfur due to large solubility of sulfide in Na2O-containing slag systems.

  16. Hydrogen sulfide inhibits the renal fibrosis of obstructive nephropathy.

    Science.gov (United States)

    Song, Kai; Wang, Fen; Li, Qian; Shi, Yong-Bing; Zheng, Hui-Fen; Peng, Hanjing; Shen, Hua-Ying; Liu, Chun-Feng; Hu, Li-Fang

    2014-06-01

    Hydrogen sulfide has recently been found decreased in chronic kidney disease. Here we determined the effect and underlying mechanisms of hydrogen sulfide on a rat model of unilateral ureteral obstruction. Compared with normal rats, obstructive injury decreased the plasma hydrogen sulfide level. Cystathionine-β-synthase, a hydrogen sulfide-producing enzyme, was dramatically reduced in the ureteral obstructed kidney, but another enzyme cystathionine-γ-lyase was increased. A hydrogen sulfide donor (sodium hydrogen sulfide) inhibited renal fibrosis by attenuating the production of collagen, extracellular matrix, and the expression of α-smooth muscle actin. Meanwhile, the infiltration of macrophages and the expression of inflammatory cytokines including interleukin-1β, tumor necrosis factor-α, and monocyte chemoattractant protein-1 in the kidney were also decreased. In cultured kidney fibroblasts, a hydrogen sulfide donor inhibited the cell proliferation by reducing DNA synthesis and downregulating the expressions of proliferation-related proteins including proliferating cell nuclear antigen and c-Myc. Further, the hydrogen sulfide donor blocked the differentiation of quiescent renal fibroblasts to myofibroblasts by inhibiting the transforming growth factor-β1-Smad and mitogen-activated protein kinase signaling pathways. Thus, low doses of hydrogen sulfide or its releasing compounds may have therapeutic potentials in treating chronic kidney disease.

  17. INVESTIGATION OF THIN FILM CADMIUM SULFIDE SOLAR CELLS.

    Science.gov (United States)

    SOLAR CELLS , *CADMIUM COMPOUNDS, FILMS, SULFIDES, VAPOR PLATING, VACUUM APPARATUS, SINGLE CRYSTALS, TITANIUM, COPPER COMPOUNDS, CHLORIDES, INDIUM, MOLYBDENUM, SILICON COMPOUNDS, MONOXIDES, SURFACE PROPERTIES, ENERGY CONVERSION.

  18. Influence of iron on sulfide inhibition in dark biohydrogen fermentation.

    Science.gov (United States)

    Dhar, Bipro Ranjan; Elbeshbishy, Elsayed; Nakhla, George

    2012-12-01

    Sulfide impact on biohydrogen production using dark fermentation of glucose at 37 °C was investigated. Dissolved sulfide (S(2-)) at a low concentration (25mg/L) increased biohydrogen production by 54% relative to the control (without iron addition). Whereas on initial dissolved S(2-) concentration of 500 mg/L significantly inhibited the biohydrogen production with total cumulative biohydrogen decreasing by 90% compared to the control (without iron addition). At sulfide concentrations of 500 mg S(2-)/L, addition of Fe(2+) at 3-4 times the theoretical requirement to precipitate 100% of the dissolved S(2-) entirely eliminated the inhibitory effect of sulfide.

  19. MEASURING METAL SULFIDE COMPLEXES IN OXIC RIVER WATERS WITH SQUARE WAVE VOLTAMMETRY. (R825395)

    Science.gov (United States)

    A sulfide identification protocol was developed to quantify specific metal sulfides that could exist in river water. Using a series of acid additions, nitrogen purges, and voltammetric analyses, metal sulfides were identified and semiquantified in three specific gr...

  20. Toxicological analysis of 17 autopsy cases of hydrogen sulfide poisoning resulting from the inhalation of intentionally generated hydrogen sulfide gas.

    Science.gov (United States)

    Maebashi, Kyoko; Iwadate, Kimiharu; Sakai, Kentaro; Takatsu, Akihiro; Fukui, Kenji; Aoyagi, Miwako; Ochiai, Eriko; Nagai, Tomonori

    2011-04-15

    Although many cases of fatal hydrogen sulfide poisoning have been reported, in most of these cases, it resulted from the accidental inhalation of hydrogen sulfide gas. In recent years, we experienced 17 autopsy cases of fatal hydrogen sulfide poisoning due to the inhalation of intentionally generated hydrogen sulfide gas. In this study, the concentrations of sulfide and thiosulfate in blood, urine, cerebrospinal fluid and pleural effusion were examined using GC/MS. The sulfide concentrations were blood: 0.11-31.84, urine: 0.01-1.28, cerebrospinal fluid: 0.02-1.59 and pleural effusion: 2.00-8.59 (μg/ml), while the thiosulfate concentrations were blood: 0-0.648, urine: 0-2.669, cerebrospinal fluid: 0.004-0.314 and pleural effusion: 0.019-0.140 (μmol/ml). In previous reports, the blood concentration of thiosulfate was said to be higher than that of sulfide in hydrogen sulfide poisoning cases, although the latter was higher than the former in 8 of the 14 cases examined in this study. These results are believed to be strongly influenced by the atmospheric concentration of hydrogen sulfide the victims were exposed to and the time interval between exposure and death.

  1. Cupriavidus necator H16 uses flavocytochrome c-sulfide dehydrogenase to oxidize self-produced and spiked sulfide.

    Science.gov (United States)

    Lü, Chuanjuan; Xia, Yongzhen; Liu, Daixi; Zhao, Rui; Gao, Rui; Liu, Honglei; Xun, Luying

    2017-09-01

    Heterotrophic bacteria producing sulfide (H2S, HS(-), and S(2-)) during aerobic growth is a common phenomenon. Some with sulfide:quinone oxidoreductase (SQR) and persulfide dioxygenase (PDO) can oxidize self-produced sulfide to sulfite and thiosulfate, but others without these enzymes will release sulfide into the medium, from which H2S can volatilize into the gas phase. Here, we report Cupriavidus necator H16 with the fccAB genes, encoding flavocytochrome c-sulfide dehydrogenases (FCSDs), also oxidized self-produced H2S. The mutant with fccAB being deleted accumulated and released H2S. When fccAB were expressed in a Pseudomonas aeruginosa strain Pa3K with deletions of its sqr and pdo genes, the recombinant rapidly oxidized sulfide to sulfane sulfur. When PDO was also cloned into the recombinant, the recombinant with both FCSD and PDO oxidized sulfide to sulfite and thiosulfate. Thus, the proposed pathway is similar to the pathway catalyzed by SQR and PDO, in which FCSD oxidizes sulfide to polysulfide, polysulfide spontaneously reacts with GSH to produce GSSH, and PDO oxidizes GSSH to sulfite, which chemically reacts with polysulfide to produce thiosulfate. About 20.6% of sequenced bacterial genomes contain SQR, and only 3.9% contain FCSD. This is not a surprise since SQR is more efficient in conserving energy because it passes electrons from sulfide oxidation into the electron transport chain at the quinone level, while FCSD passes electrons to cytochrome c The transport of electrons from the latter to O2 conserves less energy. FCSDs are grouped into three subgroups, well conserved at taxonomic levels. Thus, our data show the diversity in sulfide oxidation by heterotrophic bacteria.Importance Heterotrophic bacteria with SQR and PDO can oxidize self-produced sulfide and do not release H2S into the gas phase. C. necator H16 has FCSD but not SQR, and it does not release H2S. We confirmed that the bacterium used FCSD for the oxidation of self-produced sulfide. The

  2. Evidence supporting biologically mediated sulfide oxidation in hot spring ecosystems

    Science.gov (United States)

    Cox, A. D.; Shock, E.

    2011-12-01

    The sulfide concentration of fluids in hydrothermal ecosystems is one of several factors determining the transition to microbial photosynthesis (Cox et al., 2011, Chem. Geol. 280, 344-351). To investigate the loss of sulfide in Yellowstone hot spring systems, measurements of total dissolved sulfide with respect to time were made in incubation experiments conducted on 0.2-micron filtered (killed controls) vs. unfiltered hot spring water at locations with three different pH:sulfide combinations (pH 2.5 with 50 μM sulfide, 5.2 with 5.6 μM sulfide, and 8.3 with 86 μM sulfide). At the higher pH values, the experiments yielded similar rates of sulfide loss in filtered and unfiltered water of approximately 0.8 (pH 5.2) and 7.6 nmol sulfide L-1s-1 (pH 8.3). At the acidic spring, the unfiltered water lost sulfide at a rate 1.6 times that of the filtered water (8.2 vs. 5 nmol sulfide L-1s-1). These results suggest that the pelagic biomass at the pH 5.2 and 8.3 springs may not affect sulfide loss, whereas in the pH 2.5 spring there appears to be an effect. In addition, the incubation of filamentous biomass with unfiltered water increased the rate of sulfide loss by approximately two-fold at a pH of 2.5 (59 vs. 31 nmol L-1s-1; Cox et al., 2011), five-fold at a pH of 5.2 (3.9 vs. 0.8 nmol sulfide L-1s-1), and barely increased the rate of sulfide loss at a pH of 8.3 (9.1 vs. 8.4 nmol sulfide L-1s-1). Sulfide is predominately present as HS- at a pH of 8.3, which may not be taken up as easily by microorganisms as the H2S (aq) that dominates sulfide speciation at pH 2.5 and 5.2. That the loss of sulfide at acidic pH is due to biotic rather than abiotic factors is further supported by studies with whole mat samples that show greater sulfide consumption than killed controls (D'Imperio et al., 2008, AEM 74, 5802-5808). Taken together, the results of these experiments suggest that the majority of sulfide oxidation occurs in the filamentous biomass of hot spring ecosystems, although

  3. Modeling Sulfides, pH and Hydrogen Sulfide Gas in the Sewers of San Francisco.

    Science.gov (United States)

    Vollertsen, Jes; Revilla, Nohemy; Hvitved-Jacobsen, Thorkild; Nielsen, Asbjørn Haaning

    2015-11-01

    An extensive measuring campaign targeted on sewer odor problems was undertaken in San Francisco. It was assessed whether a conceptual sewer process model could reproduce the measured concentrations of total sulfide in the wastewater and H2S gas in the sewer atmosphere, and to which degree such simulations have potential for further improving odor and sulfide management. The campaign covered measurement of wastewater sulfide by grab sampling and diurnal sampling, and H2S gas in the sewer atmosphere was logged. The tested model was based on the Wastewater Aerobic/Anaerobic Transformations in Sewers (WATS) sewer process concept, which never had been calibrated to such an extensive dataset. The study showed that the model was capable of reproducing the general levels of wastewater sulfide, wastewater pH, and sewer H2S gas. It could also reproduce the general variability of these parameters, albeit with some uncertainty. It was concluded that the model could be applied for the purpose in mind.

  4. The inhibitory effect of Sulindac on human pancreatic cancer cells' proliferation by targeting survivin/ Aurora B pathway%舒林酸经survivin/Aurora B途径对人胰腺癌细胞分裂的阻断效应

    Institute of Scientific and Technical Information of China (English)

    范学科; 廖宇圣; 张翠芳; 陈芬; 高慧涛; 覃华; 李德民; 赵秋

    2008-01-01

    Objective To observe the expression of survivin and Aurora B in human pancreatic cancer BXPC3 cells after the treatment of sulindac and to explore the potential mechanism. Methods MTr assay was used to determine the effect of sulindac on the proliferation of the BXPC3 cells. RT-PCR was used to detect the expression of mRNA level of survivin and Aurora B, western blot was used to detect protein expression of survivin and Aurora B Thr-232. Cell cycle and apoptosis were detected by flow eytometry (FCM). Results The BXPC3 cells were inhibited by sulindac in a dose and time-dependent manner; the expression of mRNA of survivin and Aurora B were both significantly decreased from 1.5644 and 0.6554 to 0. 4372 and 0.1132 (P< 0.01), the expression of survivin protein and the phosphorylation of Aurora B Thr-232 were also decreased from 1.2735 and 0.4680 to 0.2126 and 0.2546 (P<0.01); the proportion of cells in the G0/G1 phase was increased from (56.65±1.93)% to (70.58±3.21)% (P<0.01). Conclusions Sulindac had inhibitory effects on the growth of BXPC3 cells, the possible mechanism was via decreasing the expression of survivin which depressed the activity of Aurora B, then the CPC was influenced. The most of the cells were blocked in the G0/G1 phase, and the cells' mitosis was inhibited.%目的 观察舒林酸处理胰腺癌细胞BxPC3后对survivin、Aurora B表达及细胞周期和增殖的影响,探讨舒林酸的作用机制.方法 应用MTT法检测舒林酸对BxPC3细胞的增殖抑制作用,RT-PCR法检测survivin mRNA、Aurora B mRNA的表达,Western blot法检测survivin蛋白表达及Aurora BThr-232磷酸化水平,流式细胞仪检测细胞周期变化.结果 舒林酸呈时间和剂量依赖性抑制BxPC3细胞增殖.经500μmoL/L舒林酸作用细胞48 h后,survivin mRNA和Aurora B mRNA表达量分别从1.56和0.66下降到0.44和0.11(P<0.01);survivin蛋白表达从1.27下降到0.21(P<0.01),Aurora BThr-232磷酸化水平从0.47下降到0.25(P<0.01);G0/G1

  5. Transparent zinc sulfide processed from nanocrystalline powders

    Science.gov (United States)

    Gao, De; Stefanik, Todd S.

    2013-06-01

    Nanocerox produces oxide nanopowders via flame spray pyrolysis that have proven effective in the processing of a host of high quality optical ceramic materials. In order to produce LWIR windows to compete with ZnS, however, oxide materials are not suitable. Nanocerox has therefore developed aqueous synthesis techniques for the production of zinc sulfide nanopowders. The proprietary processing technique allows control of primary particle size, high purity, low levels of agglomeration, and cost effective synthesis. Crystallinity, particle size, and purity of the powders will be presented. Characterization of parts fabricated from these powders via sinter/HIP processing will also be discussed, including optical performance and microstructural characterization.

  6. Iron Sulfide Minerals in Black Sea Sediments

    Science.gov (United States)

    Franke, Christine; Robin, Eric; Henkel, Susann; Courtin-Nomade, Alexandra; Bleil, Ulrich

    2010-05-01

    This study presents a mutidisciplinary geochemical and environmental magnetic approach, integrating advanced mineralogical techniques to better understand the physicochemical syn-sedimentary and post-depositional processes in the anoxic sediments from the northwestern Black Sea. The investigated gravity core GC 214 was retrieved in 2007 during RV METEOR cruise M72/1 west of the Crimean Peninsula in a water depth of 1686 mbsf. Geochemical analyses of the pore water and solid phase indicate non-steady state sedimentation. The oxygen-depleted water column conditions, anaerobic oxidation of methane (AOM), and related microbial-driven sulfate reduction favor a highly complex iron sulfide mineral assemblage in the sediment column. The detailed magnetic susceptibility and remanence measurements indicate an irregularly stratified depth profile showing intervals of particularly high values. Further environmental magnetic analyses of hysteresis loops depict strongly elevated coercivity values for those depth horizons, suggesting metastable ferrimagnetic greigite (Fe3S4) as the main magnetic carrier phase. Automated chemical classification (ACC), using electron dispersive spectrometer (EDS) attached to a JEOL 840 scanning electron microscope (SEM) on dispersed particle samples permitted the absolutequantification of the various present iron mineral phases with depth, identified as greigite (Fe3S4), pyrrhotite (Fe7S8), pyrite (FeS2), and monosulfides (FeS), such as troilite or markasite. The statistically stable ACC analyses were carried out on magnetic extracts and density separates to be able to calculate budgets between the different present iron sulfides. We also obtained excellent correlations between the different iron sulfide concentrations and the magnetic signal, which open the possibility to link the absolute particle concentrations to the magnetic signal. Additional synchrotron based micro-XRD analyses on polished sections yield inside into the details of the

  7. Mercury Sulfide Dimorphism in Thioarsenate Glasses

    OpenAIRE

    KASSEM, Mohammad; Sokolov, Anton; Cuisset, Arnaud,; Usuki, Takeshi; Khaoulani, Sohayb; Masselin, Pascal; Le Coq, David,; Feygenson, M.; Benmore, C. J.; Hannon, Alex,; Neuefeind, J. C.; Bychkov, Eugene

    2016-01-01

    International audience; Crystalline mercury sulfide exists in two drastically different polymorphic forms in different domains of the P,T-diagram: red chain-like insulator α-HgS, stable below 344 °C, and black tetrahedral narrow-band semiconductor β-HgS, stable at higher temperatures. Using pulsed neutron and high-energy X-ray diffraction, we show that these two mercury bonding pattern are present simultaneously in mercury thioarsenate glasses HgS-As2S3. The population and interconnectivity o...

  8. Diurnal changes in pore water sulfide concentrations in the seagrass Thalassia testudinum beds: the effects of seagrasses on sulfide dynamics.

    Science.gov (United States)

    Lee; Dunton

    2000-12-20

    The dynamics of the seagrass-sulfide interaction were examined in relation to diel changes in sediment pore water sulfide concentrations in Thalassia testudinum beds and adjacent bare areas in Corpus Christi Bay and lower Laguna Madre, Texas, USA, during July 1996. Pore water sulfide concentrations in seagrass beds were significantly higher than in adjacent bare areas and showed strong diurnal variations; levels significantly decreased during mid-day at shallow sediment depths (0-10 cm) containing high below-ground tissue biomass and surface area. In contrast, diurnal variations in sediment sulfide concentrations were absent in adjacent bare patches, and at deeper (>10 cm) sediment depths characterized by low below-ground plant biomass or when the grasses were experimentally shaded. These observations suggest that the mid-day depressions in sulfide levels are linked to the transport of photosynthetically produced oxygen to seagrass below-ground tissues that fuels sediment sulfide oxidation. Lower sulfide concentrations in bare areas are likely a result of low sulfate reduction rates due to low organic matter available for remineralization. Further, high reoxidation rates due to rapid exchange between anoxic pore water and oxic overlying water are probably stimulated in bare areas by higher current velocity on the sediment surface than in seagrass beds. The dynamics of pore water sulfides in seagrass beds suggest no toxic sulfide intrusion into below-ground tissues during photosynthetic periods and demonstrate that the sediment chemical environment is considerably modified by seagrasses. The reduced sediment sulfide levels in seagrass beds during photosynthetic periods will enhance seagrass production through reduced sulfide toxicity to seagrasses and sediment microorganisms related to the nutrient cycling.

  9. Recent findings on sinks for sulfide in gravity sewer networks

    DEFF Research Database (Denmark)

    Nielsen, Asbjørn Haaning; Hvitved-Jacobsen, Thorkild; Vollertsen, Jes

    2006-01-01

    summarizes this newly obtained knowledge and emphasizes important implications of the findings. Model simulations of the in-sewer processes important for the sulfur cycle showed that sulfide oxidation in the wetted biofilm is typically the most important sink for dissolved sulfide in gravity sewers. However...

  10. Hydrogen sulfide: physiological properties and therapeutic potential in ischaemia.

    Science.gov (United States)

    Bos, Eelke M; van Goor, Harry; Joles, Jaap A; Whiteman, Matthew; Leuvenink, Henri G D

    2015-03-01

    Hydrogen sulfide (H2 S) has become a molecule of high interest in recent years, and it is now recognized as the third gasotransmitter in addition to nitric oxide and carbon monoxide. In this review, we discuss the recent literature on the physiology of endogenous and exogenous H2 S, focusing upon the protective effects of hydrogen sulfide in models of hypoxia and ischaemia.

  11. Long-term outcome of sporadic and FAP-associated desmoid tumors treated with high-dose selective estrogen receptor modulators and sulindac: a single-center long-term observational study in 134 patients.

    Science.gov (United States)

    Quast, Daniel Robert; Schneider, Ralph; Burdzik, Emanuel; Hoppe, Steffen; Möslein, Gabriela

    2016-01-01

    Aim of this study is to evaluate the outcome of long-term conservative treatment with sulindac and high-dose selective estrogen receptor modulators (SERMs) for sporadic and FAP-associated desmoid tumors. Desmoids are very rare tumors in the general population but occur frequently in FAP patients, being encountered in 23-38 %. Treatment of desmoids is still most controversial since response cannot be predicted and they are prone to develop recurrence. This study included all desmoid patients that were treated and followed at our institution and had completed at least 1 year of treatment. Response was defined as stable size or regression of desmoid size between two CT or MRI scans. A total of 134 patients were included. 64 (47.8 %) patients had a confirmed diagnosis of FAP, 69 (51.5 %) patients were sporadic. Overall 114 (85.1 %) patients showed regressive or stable desmoid size. Patients with previous history of multiple desmoid-related surgeries showed less-favorable response. The mean time to reach at least stable size was 14.9 (±9.1) months. After regression or stabilization, medication was tapered in 69 (60.5 %) of the treated patients with only one long-term recurrence after >10 years. The results of this study fortify the role of sulindac and high-dose SERMs as an effective and safe treatment for both, sporadic and FAP-associated desmoid tumors. While invasive treatment frequently results in high recurrence rates, high morbidity and high mortality, this conservative treatment is successful in most patients. The recurrence rate is negligible with no desmoid-related mortality in this large series. Therefore surgical resection, especially for mesenteric desmoids, should be deferred favoring this convincingly effective, well tolerated regimen.

  12. Effect of palladium on sulfide tarnishing of noble metal alloys.

    Science.gov (United States)

    Suoninen, E; Herø, H; Minni, E

    1985-10-01

    Electron spectroscopic studies of Au-Ag-Cu alloys of the type used for dental castings show that small additions (less than or equal to 3 wt%) of palladium reduce essentially the thickness of the sulfide layer formed on surfaces of samples treated in aqueous Na2S solutions. Relative to silver, palladium does not enrich in the sulfide, but statistically significant enrichment is found immediately below the sulfide layer. This enrichment probably takes place during the exposure of the substrate surface to atmosphere before the sulfiding treatment. The mechanism of the impeding effect of palladium on sulfiding is assumed to be a decrease in diffusion from the bulk alloy to the surface due to the enriched layer. The effect cannot be explained by changes in the electronic structure of the alloy due to palladium alloying.

  13. Influence of Water Salinity on Air Purification from Hydrogen Sulfide

    Directory of Open Access Journals (Sweden)

    Leybovych L.I.

    2015-12-01

    Full Text Available Mathematical modeling of «sliding» water drop motion in the air flow was performed in software package FlowVision. The result of mathematical modeling of water motion in a droplet with diameter 100 microns at the «sliding» velocity of 15 m/s is shown. It is established that hydrogen sulfide oxidation occurs at the surface of phases contact. The schematic diagram of the experimental setup for studying air purification from hydrogen sulfide is shown. The results of the experimental research of hydrogen sulfide oxidation by tap and distilled water are presented. The dependence determining the share of hydrogen sulfide oxidized at the surface of phases contact from the dimensionless initial concentration of hydrogen sulfide in the air has been obtained.

  14. Hierarchical Architecturing for Layered Thermoelectric Sulfides and Chalcogenides

    Directory of Open Access Journals (Sweden)

    Priyanka Jood

    2015-03-01

    Full Text Available Sulfides are promising candidates for environment-friendly and cost-effective thermoelectric materials. In this article, we review the recent progress in all-length-scale hierarchical architecturing for sulfides and chalcogenides, highlighting the key strategies used to enhance their thermoelectric performance. We primarily focus on TiS2-based layered sulfides, misfit layered sulfides, homologous chalcogenides, accordion-like layered Sn chalcogenides, and thermoelectric minerals. CS2 sulfurization is an appropriate method for preparing sulfide thermoelectric materials. At the atomic scale, the intercalation of guest atoms/layers into host crystal layers, crystal-structural evolution enabled by the homologous series, and low-energy atomic vibration effectively scatter phonons, resulting in a reduced lattice thermal conductivity. At the nanoscale, stacking faults further reduce the lattice thermal conductivity. At the microscale, the highly oriented microtexture allows high carrier mobility in the in-plane direction, leading to a high thermoelectric power factor.

  15. Mechanical properties of gutta-percha sulfide modified asphalt

    Science.gov (United States)

    Zou, X. Y.; Gu, X. Y.; Wang, X. W.

    2017-01-01

    Gutta-percha is the isomer of caoutchouc and can be used to enhance the performance of asphalt. In this paper, the produce proceedings of gutta-percha sulfide and gutta-percha sulfide modified asphalt are introduced. The performance indices of gutta-percha sulfide modified asphalt samples with different proportions are examined based on laboratory tests and the optimum ratio of gutta-percha and sulfur is decided.The micromechanism, temperature sensitivity, high and low temperature properties and viscoelasticity of the polymer modified asphalt are analyzed to discuss the modified mechanism and to decide the optimal polymer content. Low temperature bending tests are carried out to verify the low temperature performance of gutta-percha sulfide modified asphalt mixture. Research results showed that gutta-percha sulfide modified asphalt has good low temperature performance and a promising application prospect in the cold regions.

  16. Regulation of bacterial sulfate reduction and hydrogen sulfide fluxes in the central Namibian coastal upwelling zone

    DEFF Research Database (Denmark)

    Bruchert, V.; Jørgensen, BB; Neumann, K.;

    2003-01-01

    and the low capacity to oxidize and trap sulfide. The inner shelf break marks the seaward border of sulfidic bottom waters, and separates two different regimes of bacterial sulfate reduction. In the sulfidic bottom waters on the shelf, up to 55% of sulfide oxidation is mediated by the large nitrate...... to the sediment-water interface and reduce the hydrogen sulfide flux to the water column. Modeling of pore water sulfide concentration profiles indicates that sulfide produced by bacterial sulfate reduction in the uppermost 16 cm of sediment is sufficient to account for the total flux of hydrogen sulfide...... to the water column. However, the total pool of hydrogen sulfide in the water column is too large to be explained by steady state diffusion across the sediment-water interface. Episodic advection of hydrogen sulfide, possibly triggered by methane eruptions, may contribute to hydrogen sulfide in the water...

  17. Calculation of sulfide capacities of multicomponent slags

    Science.gov (United States)

    Pelton, Arthur D.; Eriksson, Gunnar; Romero-Serrano, Antonio

    1993-10-01

    The Reddy-Blander model for the sulfide capacities of slags has been modified for the case of acid slags and to include A12O3 and TiO2 as components. The model has been extended to calculate a priori sulfide capacities of multicomponent slags, from a knowledge of the thermodynamic activities of the component oxides, with no adjustable parameters. Agreement with measurements is obtained within experimental uncertainty for binary, ternary, and quinary slags involving the components SiO2-Al2O3-TiO2-CaO-MgO-FeO-MnO over wide ranges of composition. The oxide activities used in the computations are calculated from a database of model parameters obtained by optimizing thermodynamic and phase equilibrium data for oxide systems. Sulfur has now been included in this database. A computing system with automatic access to this and other databases has been developed to permit the calculation of the sulfur content of slags in multicomponent slag/metal/gas/solid equilibria.

  18. Hydrogen sulfide and polysulfides as biological mediators.

    Science.gov (United States)

    Kimura, Hideo

    2014-10-09

    Hydrogen sulfide (H2S) is recognized as a biological mediator with various roles such as neuromodulation, regulation of the vascular tone, cytoprotection, anti-inflammation, oxygen sensing, angiogenesis, and generation of mitochondrial energy. It is produced by cystathionine β-synthase (CBS), cystathionine γ-lyase (CSE), and 3-mercaptopyruvate sulfurtransferase (3MST). The activity of CBS is enhanced by S-adenosyl methionine (SAM) and glutathionylation, while it is inhibited by nitric oxide (NO) and carbon monoxide (CO). The activity of CSE and cysteine aminotransferase (CAT), which produces the 3MST substrate 3-mercaptopyruvate (3MP), is regulated by Ca2+. H2S is oxidized to thiosulfate in mitochondria through the sequential action of sulfide quinone oxidoreductase (SQR), sulfur dioxygenase, and rhodanese. The rates of the production and clearance of H2S determine its cellular concentration. Polysulfides (H2Sn) have been found to occur in the brain and activate transient receptor potential ankyrin 1 (TRPA1) channels, facilitate the translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) to the nucleus, and suppress the activity of phosphatase and tensin homolog (PTEN) by sulfurating (sulfhydrating) the target cysteine residues. A cross talk between H2S and NO also plays an important role in cardioprotection as well as regulation of the vascular tone. H2S, polysulfides, and their cross talk with NO may mediate various physiological and pathophysiological responses.

  19. First detection of doubly deuterated hydrogen sulfide

    CERN Document Server

    Vastel, C; Ceccarelli, C; Pearson, J

    2003-01-01

    This work was carried out with using the Caltech Submillimeter Observatory and presents the observational study of HDS and D2S towards a sample of Class 0 sources, and dense cores. We report the first detection of doubly deuterated hydrogen sulfide (D2S) in two dense cores and analyze the chemistry of these molecules aiming to help understand the deuteration processes in the interstellar medium. The observed values of the D2S/HDS ratio, and upper limits, require an atomic D/H ratio in the accreting gas of 0.1-1. The study presented in this Letter supports the hypothesis that formaldehyde, methanol and hydrogen sulfide are formed on the grain surfaces, during the cold pre-stellar core phase, where the CO depleted gas has large atomic D/H ratios. The high values for the D/H ratios are consistent with the predictions of a recent gas-phase chemical model that includes H3+ and its deuterated isotopomers, H2D+, D2H+ and D3+ (Roberts et al. 2003).

  20. Hydrogen Sulfide and Polysulfides as Biological Mediators

    Directory of Open Access Journals (Sweden)

    Hideo Kimura

    2014-10-01

    Full Text Available Hydrogen sulfide (H2S is recognized as a biological mediator with various roles such as neuromodulation, regulation of the vascular tone, cytoprotection, anti-inflammation, oxygen sensing, angiogenesis, and generation of mitochondrial energy. It is produced by cystathionine β-synthase (CBS, cystathionine γ-lyase (CSE, and 3-mercaptopyruvate sulfurtransferase (3MST. The activity of CBS is enhanced by S-adenosyl methionine (SAM and glutathionylation, while it is inhibited by nitric oxide (NO and carbon monoxide (CO. The activity of CSE and cysteine aminotransferase (CAT, which produces the 3MST substrate 3-mercaptopyruvate (3MP, is regulated by Ca2+. H2S is oxidized to thiosulfate in mitochondria through the sequential action of sulfide quinone oxidoreductase (SQR, sulfur dioxygenase, and rhodanese. The rates of the production and clearance of H2S determine its cellular concentration. Polysulfides (H2Sn have been found to occur in the brain and activate transient receptor potential ankyrin 1 (TRPA1 channels, facilitate the translocation of nuclear factor erythroid 2-related factor 2 (Nrf2 to the nucleus, and suppress the activity of phosphatase and tensin homolog (PTEN by sulfurating (sulfhydrating the target cysteine residues. A cross talk between H2S and NO also plays an important role in cardioprotection as well as regulation of the vascular tone. H2S, polysulfides, and their cross talk with NO may mediate various physiological and pathophysiological responses.

  1. Carbonyl sulfide: No remedy for global warming

    Science.gov (United States)

    Taubman, Steven J.; Kasting, James F.

    1995-04-01

    The enhancement of the stratospheric aerosol layer caused by the eruption of Mt. Pinatubo (June 15, 1991), and the subsequent cooling of the earth's lower atmosphere [Dutton and Christy, 1992; Minnis et al., 1993] shows that stratospheric aerosols can have a strong effect on the earth's climate. This supports the notion that the intentional enhancement of the stratospheric aerosol layer through increased carbonyl sulfide (OCS) emissions might be an effective means for counteracting global warming. Through the use of a one-dimensional photochemical model, we investigate what effect such a program might have on global average stratospheric ozone. In addition, we consider the impact of enhanced OCS emissions on rainwater acidity and on the overall health of both plants and animals. We find that while the warming produced by a single CO2 doubling (1 to 4°C) might be offset with ozone losses of less than 5%, any attempt to use carbonyl sulfide as a permanent solution to global warming could result in depletion of global average ozone by 30% or more. We estimate that in order to achieve cooling of 4°C rainwater pH would fall to between 3.5 and 3.8. Finally, a 4°C cooling at the surface will require that ambient near ground OCS levels rise to above 10 ppmv which is probably greater than the safe exposure limit for humans. Thus, enhanced OCS emissions do not provide an environmentally acceptable solution to the problem of global warming.

  2. Normal state of metallic hydrogen sulfide

    Science.gov (United States)

    Kudryashov, N. A.; Kutukov, A. A.; Mazur, E. A.

    2017-02-01

    A generalized theory of the normal properties of metals in the case of electron-phonon (EP) systems with a nonconstant density of electron states has been used to study the normal state of the SH3 and SH2 phases of hydrogen sulfide at different pressures. The frequency dependence of the real Re Σ (ω) and imaginary ImΣ (ω) parts of the self-energy Σ (ω) part (SEP) of the Green's function of the electron Σ (ω), real part Re Z (ω), and imaginary part Im Z (ω) of the complex renormalization of the mass of the electron; the real part Re χ (ω) and the imaginary part Imχ (ω) of the complex renormalization of the chemical potential; and the density of electron states N (ɛ) renormalized by strong electron-phonon interaction have been calculated. Calculations have been carried out for the stable orthorhombic structure (space group Im3¯ m) of the hydrogen sulfide SH3 for three values of the pressure P = 170, 180, and 225 GPa; and for an SH2 structure with a symmetry of I4/ mmm ( D4 h1¯7) for three values of pressure P = 150, 180, and 225 GP at temperature T = 200 K.

  3. CALCULATION OF CONDITIONAL EQUILIBRIUM IN SERIAL MULTIPLE PRECIPITATION OF METAL SULFIDES WITH HYDROGEN SULFIDE STREAM GENERATED FROM SODIUM SULFIDE: A DIDACTIC TOOL FOR CHEMISTRY TEACHING

    Directory of Open Access Journals (Sweden)

    Renata Bellová

    2016-07-01

    Full Text Available Hydrogen sulfide is presented in textbooks as toxic, environmentally unacceptable species, however some positive effects in human metabolism were discovered in the last decades. It is important to offer students also some new information about this compound. As didactic tool in this case may serve serial precipitation of Cd2+, Cu2+, Zn2+, Mn2+ and Pb2+ ions forming various colored sulfides in bubblers with chemically generated hydrogen sulfide stream. This experiment has strong and diverse color effect for enhancing the visual perception to motivate students to understand more abstract and complex information about hydrogen sulfide. It also may be helpful in analytical chemistry courses for conditional precipitation equilibrium teaching and calculations.

  4. Synthesis of Diaryl Ethers, Diaryl Sulfides, Heteroaryl Ethers and Heteroaryl Sulfides under Microwave Heating

    Institute of Scientific and Technical Information of China (English)

    LI,Feng; ZOU,Jiong; WANG,Quan-Rui; TAO,Feng-Gang

    2004-01-01

    @@ Diaryl ether moiety is found in a pool of naturally occurring and medicinally important compounds.[1] As a consequent, considerable efforts have been devoted to the assembly of this framework.[2] Recently, we have developed a microwave heating version of the synthesis of diaryl ethers as well as aryl sulfides. Under our conditions, even the extremely electron-poor 4-nitrophenol works well and its reaction with 1-halo-4-nitrobenzenes produces 4-(nitrophenoxy)-benzonitriles in satisfactory yield. The scope of the present protocol has been expanded to hydroxylated six-membered heterocycles as well as 2-pyrimidinethiol with mildly activated aryl halides, affording heteroaryl ethers and respectively sulfides. The advantages of the present method include the wide substrate scope, no use of any metal catalysts, the ease of product isolation and high yields.

  5. Azo dye decolorization assisted by chemical and biogenic sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Prato-Garcia, Dorian [Laboratory for Research on Advanced Processes for Water Treatment, Unidad Académica Juriquilla, Instituto de Ingeniería, Universidad Nacional Autónoma de México, Blvd. Juriquilla 3001, Querétaro 76230 (Mexico); Cervantes, Francisco J. [División de Ciencias Ambientales, Instituto Potosino de Investigación Científica y Tecnológica, Camino a la Presa de San José 2055, San Luis Potosí 78216 (Mexico); Buitrón, Germán, E-mail: gbuitronm@ii.unam.mx [Laboratory for Research on Advanced Processes for Water Treatment, Unidad Académica Juriquilla, Instituto de Ingeniería, Universidad Nacional Autónoma de México, Blvd. Juriquilla 3001, Querétaro 76230 (Mexico)

    2013-04-15

    Highlights: ► Azo dyes were reduced efficiently by chemical and biogenic sulfide. ► Biogenic sulfide was more efficient than chemical sulfide. ► There was no competition between dyes and sulfate for reducing equivalents. ► Aromatic amines barely affected the sulfate-reducing process. -- Abstract: The effectiveness of chemical and biogenic sulfide in decolorizing three sulfonated azo dyes and the robustness of a sulfate-reducing process for simultaneous decolorization and sulfate removal were evaluated. The results demonstrated that decolorization of azo dyes assisted by chemical sulfide and anthraquinone-2,6-disulfonate (AQDS) was effective. In the absence of AQDS, biogenic sulfide was more efficient than chemical sulfide for decolorizing the azo dyes. The performance of sulfate-reducing bacteria in attached-growth sequencing batch reactors suggested the absence of competition between the studied azo dyes and the sulfate-reducing process for the reducing equivalents. Additionally, the presence of chemical reduction by-products had an almost negligible effect on the sulfate removal rate, which was nearly constant (94%) after azo dye injection.

  6. Measurement of plasma hydrogen sulfide in vivo and in vitro.

    Science.gov (United States)

    Shen, Xinggui; Pattillo, Christopher B; Pardue, Sibile; Bir, Shyamal C; Wang, Rui; Kevil, Christopher G

    2011-05-01

    The gasotransmitter hydrogen sulfide is known to regulate multiple cellular functions during normal and pathophysiological states. However, a paucity of concise information exists regarding quantitative amounts of hydrogen sulfide involved in physiological and pathological responses. This is primarily due to disagreement among various methods employed to measure free hydrogen sulfide. In this article, we describe a very sensitive method of measuring the presence of H₂S in plasma down to nanomolar levels, using monobromobimane (MBB). The current standard assay using methylene blue provides erroneous results that do not actually measure H₂S. The method presented herein involves derivatization of sulfide with excess MBB in 100 mM Tris-HCl buffer (pH 9.5, 0.1 mM DTPA) for 30 min in 1% oxygen at room temperature. The fluorescent product sulfide-dibimane (SDB) is analyzed by RP-HPLC using an eclipse XDB-C18 (4.6 × 250 mm) column with gradient elution by 0.1% (v/v) trifluoroacetic acid in acetonitrile. The limit of detection for sulfide-dibimane is 2 nM and the SDB product is very stable over time, allowing batch storage and analysis. In summary, our MBB method is suitable for sensitive quantitative measurement of free hydrogen sulfide in multiple biological samples such as plasma, tissue and cell culture lysates, or media.

  7. Sulfide elimination by intermittent nitrate dosing in sewer sediments

    Institute of Scientific and Technical Information of China (English)

    Yanchen Liu; Chen Wu; Xiaohong Zhou; David Z.Zhu; Hanchang Shi

    2015-01-01

    The formation of hydrogen sulfide in biofilms and sediments in sewer systems can cause severe pipe corrosions and health hazards,and requires expensive programs for its prevention.The aim of this study is to propose a new control strategy and the optimal condition for sulfide elimination by intermittent nitrate dosing in sewer sediments.The study was carried out based on lab-scale experiments and batch tests using real sewer sediments.The intermittent nitrate dosing mode and the optimal control condition were investigated.The results indicated that the sulfide-intermittent-elimination strategy by nitrate dosing is advantageous for controlling sulfide accumulation in sewer sediment.The oxidation-reduction potential is a sensitive indicator parameter that can reflect the control effect and the minimum N/S (nitrate/sulfide)ratio with slight excess nitrate is necessary for optimal conditions ofefficient sulfide control with lower carbon source loss.The opth-nal control condition is feasible for the sulfide elimination in sewer systems.

  8. Gallium sulfide and indium sulfide nanoparticles from complex precursors: Synthesis and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Dutta, D.P. [Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)]. E-mail: duttadimple@yahoo.co.in; Sharma, G. [Materials Science Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Tyagi, A.K. [Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Kulshreshtha, S.K. [Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2007-03-15

    Nanocrystalline gallium sulfide (Ga{sub 2}S{sub 3}) and indium sulfide (In{sub 2}S{sub 3}) have been prepared by a two-step process. The first step involves metathesis reaction of trimethyl gallium/indium ether adduct (Me{sub 3}Ga/In.OEt{sub 2}) with 1,2-ethanedithiol (HSCH{sub 2}CH{sub 2}SH) resulting in the formation of a polymeric precursor. The precursor complex has been characterized using Ga/In analysis, IR, proton NMR and mass spectroscopy. The thermal behavior of both complexes has been studied using thermogravimetric (TG) analysis. In the second step, these precursor complexes have been pyrolysed in furnace under flowing nitrogen atmosphere whereupon they undergo thermodestruction to yield nanometer-sized particles of gallium/indium sulfide. The nanoparticles obtained were characterized using powder X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED) and energy dispersive X-ray spectroscopy (EDS). The average size of the nanoparticles ranged from 10 to 12 nm for Ga{sub 2}S{sub 3} and 20 to 22 nm for In{sub 2}S{sub 3}, respectively. This is the first report on use of a binary single source precursor to synthesize {beta}-Ga{sub 2}S{sub 3} nanoparticles.

  9. Signaling of hydrogen sulfide and polysulfides.

    Science.gov (United States)

    Kimura, Hideo

    2015-02-10

    It has been almost two decades since the first demonstration of hydrogen sulfide (H2S) as a physiological mediator of cognitive function and vascular tone. H2S is physiologically important because it protects various organs from ischemia-reperfusion injury besides regulating inflammation, oxygen sensing, cell growth, and senescence. The production, metabolism, and regulation of H2S have been studied extensively. H2S modulates target proteins through sulfhydration (or sulfuration) or by the reduction of cysteine disulfide bonds. A large number of novel H2S-donating compounds are being developed owing to the therapeutic potential of H2S. Recently, polysulfides, rather than H2S, have been identified as molecules that sulfhydrate (or sulfurate) their target proteins.

  10. Structure of 4-methylpyridinium Hydrogen Sulfide

    Science.gov (United States)

    Andras, Maria T.; Hepp, Aloysius F.; Fanwick, Phillip E.; Martuch, Robert A.; Duraj, Stan A.; Gordon, Edward M.

    1994-01-01

    4-Methylpyridinium hydrogen sulfide, (C6H7NH)HS, M(sub r) = 127.21, consists of C6H7NH(+) cations and HS(-) anions. Z = 2 for the crystal with monoclinic space group Cm (#8), dimensions of a = 8.679(2) A, b = 7.964(1) A, and c = 4.860(2) A, an angle beta of 101.10(2) degrees, and a volume of V = 329.6(3) A(exp 3). R = 0.039 and R(sub w) = 0.048 for 385 reflections with F(sub o)(exp 2) greater than 3 sigma(F(sub o)(exp 2)) and 59 variables. Both the C6H7NH(+) cation and the HS(-) anion lie on crystallographic mirror planes with the N,S, two carbon atoms, and two hydrogen atoms positioned in the planes. The hydrogen atom of the HS(-) anion was not located.

  11. Hydrogen sulfide in a circumstellar envelope

    Science.gov (United States)

    Ukita, N.; Morris, M.

    1983-01-01

    A search for hydrogen sulfide in the cool circumstellar envelopes of 25 stars was made using the 1(10)-1(01) rotational line at 1.8 mm. It was detected in the bipolar nebula/OH maser OH231.8+4.2, an object having a high rate of mass loss. An approximate analysis indicates that 1/60 of the sulfur in this outflowing envelope is in the form of H2S, a fraction which may be similar to that in the atmosphere of the central star. In addition, the shape of the observed line profile is discussed in terms of a possible variation of the outflow velocity with latitude above the system's equatorial plane.

  12. Hydrogen sulfide in gastrointestinal and liver physiopathology.

    Science.gov (United States)

    Cipriani, Sabrina; Mencarelli, Andrea

    2011-04-01

    Hydrogen sulfide (H(2)S) is a gas that can be formed by the action of two enzymes, cystathionine gamma lyase (CSE) and cystathionine beta synthase (CBS). H(2)S has been known for hundreds of years for its poisoning effect, however the idea that H(2)S is not only a poison, but can exert a physiological role in mammalian organisms, originates from the evidence that this gaseous mediator is produced endogenously. In addition to H(2)S synthesis by gastrointestinal tissue, the intestinal mucosa, particularly in the large intestine, is regularly exposed to high concentrations of H(2)S that are generated by some species of bacteria and through the reduction of unabsorbed intestinal inorganic sulphate. This review reports on the effects of H(2)S in the gastrointestinal tract and liver and provides information on the therapeutic applications of H(2)S-donating drugs.

  13. Modulation of hydrogen sulfide by vascular hypoxia

    Directory of Open Access Journals (Sweden)

    Osmond JM

    2014-08-01

    Full Text Available Jessica M Osmond, Nancy L KanagyVascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, NM, USAAbstract: Hydrogen sulfide (H2S has emerged as a key regulator of cardiovascular function. This gasotransmitter is produced in the vasculature and is involved in numerous processes that promote vascular homeostasis, including vasodilation and endothelial cell proliferation. Although H2S plays a role under physiological conditions, it has become clear in recent years that hypoxia modulates the production and action of H2S. Furthermore, there is growing evidence that H2S is cytoprotective in the face of hypoxic insults. This review focuses on the synthesis and signaling of H2S in hypoxic conditions in the vasculature, and highlights recent studies providing evidence that H2S is a potential therapy for preventing tissue damage in hypoxic conditions.Keywords: H2S, cystathionine γ-lyase, vascular smooth muscle, endothelium

  14. Effect of radiation on wettability and floatability of sulfide minerals

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The feasibility for modifying the wettability and floatability of sulfide minerals by electron beam irradiation has been studied experimentally. The wettability of crystalline pyrite and floatability of some sulfide as pyrite, arsenopyrite, chalcopyrite and marmatite after irradiation were examined by flotation in a modified Hallimond tube. Experimental results show that the hydrophobicity of crystalline pyrite enhances with the increase of irradiation dose in a low dose range. And the flotation responses of sulfide minerals on irradiation dosevary with the mineral species and particle size. The floatability of minerals can be regulated by altering irradiation dose. An explanationfor the mechanism has been suggested based on the principle of radiation chemistry.

  15. Sulfide capacities of MnO-SiO2 slags

    Science.gov (United States)

    Reddy, Ramana G.; Blander, Milton

    1989-04-01

    Sulfide capacities of binary MnO-SiO2 slags at 1773 and 1923 K were calculated thermodynamically. Only known data, such as the standard free energy of formation of MnO and MnS and activities of MnO in the melt, are used in making calculations based on fundamental concepts. Excellent agreement is found between our calculations and published experimental data. Correlations of sulfide capacities, based on optical basicity using Pauling electronegativities or empirically deduced optical basicities, differ from the experimental data in both magnitude and concentration dependence. Our method provides useful predictions of sulfide capacities a priori.

  16. Nanomaterials for the Selective Detection of Hydrogen Sulfide in Air

    Science.gov (United States)

    Llobet, Eduard; Brunet, Jérôme; Pauly, Alain; Ndiaye, Amadou; Varenne, Christelle

    2017-01-01

    This paper presents a focused review on the nanomaterials and associated transduction schemes that have been developed for the selective detection of hydrogen sulfide. It presents a quite comprehensive overview of the latest developments, briefly discusses the hydrogen sulfide detection mechanisms, identifying the reasons for the selectivity (or lack of) observed experimentally. It critically reviews performance, shortcomings, and identifies missing or overlooked important aspects. It identifies the most mature/promising materials and approaches for achieving inexpensive hydrogen sulfide sensors that could be employed in widespread, miniaturized, and inexpensive detectors and, suggests what research should be undertaken for ensuring that requirements are met. PMID:28218674

  17. Micellar-mediated extractive spectrophotometric determination of hydrogen sulfide/sulfide through Prussian Blue reaction: application to environmental samples.

    Science.gov (United States)

    Pandurangappa, Malingappa; Samrat, Devaramani

    2010-01-01

    A sensitive surfactant-mediated extractive spectrophotometric method has been developed, based on the reaction of ferric iron with sulfide to form ferrous iron and its subsequent reaction with ferricyanide to form Prussian Blue, to quantify trace levels of hydrogen sulfide/sulfide in environmental samples. The method obeys Beer's law in the concentration range 2-10 microg of sulfide in 25 mL of aqueous phase with molar absorptivity (epsilon) of 3.92 x 10(4) L mol(-1) cm(-1). The colored species has been extracted into isoamyl acetate in the presence of a cationic surfactant i.e. cetylpyridinium chloride, to enhance the sensitivity of the method with epsilon value 5.2 x 10(4) L mol(-1) cm(-1). The relative standard deviation has been found to be 0.69% for 10 determinations at 4 microg of sulfide and the limit of detection was 0.009 microg mL(-1). The interference from common anions and cations has been studied. The proposed method has been applied to the determination of residual hydrogen sulfide in the laboratory fume hood as well as ambient atmospheric hydrogen sulfide in the vicinity of open sewer lines after fixing the analyte in ionic form using suitable trapping medium.

  18. Micro-aeration for hydrogen sulfide removal from biogas

    Science.gov (United States)

    Duangmanee, Thanapong

    The presence of sulfur compounds (e.g. protein, sulfate, thiosulfate, sulfite, etc.) in the feed stream generates highly corrosive and odorous hydrogen sulfide during anaerobic digestion. The high sulfide level in the biogas stream is not only poisonous to many novel metal catalysts employed in thermo-catalytic processes but also reduces the quality of methane to produce renewable energy. This study used an innovative, low-maintenance, low-cost biological sulfide removal technology to remove sulfides simultaneously from both gas and liquid phase. ORP (Oxidation-Reduction-Potential) was used as the controlling parameter to precisely regulate air injection to the sulfide oxidizing unit (SOU). The microaeration technique provided just enough oxygen to partially oxidize sulfides to elemental sulfur without inhibiting methanogenesis. The SOU was equipped with a diffuser at the bottom for the dispersion of sulfide-laden biogas and injected air throughout the column. The SOU can be operated as a standalone unit or coupled with an anaerobic digester to simultaneously remove sulfide from the biogas and effluent. The integrated system was capable of reducing hydrogen sulfide in biogas from 2,450 to less than 2 ppmV with minimal sulfate production at the highest available sulfide loading rate of 0.24 kg/m3-day. More than 98% of sulfide removed was recovered as elemental sulfur. However, the standalone SOU was able to operate at high hydrogen sulfide loading of 1.46 kg/m 3-day at inlet sulfide concentration of 3000 ppmV and reduce the off-gas hydrogen sulfide concentrations to less than 10 ppmV. The experiment also revealed that the ORP controlled aeration was sensitive enough to prevent oxygen overdosing (dampening effect) during unexpected surges of aeration. Using generalized linear regression, a model predicting output H2S concentration based on input H2S concentrations, SOU medium heights, and biogas flow rates, was derived. With 95% confidence, output H2S concentration

  19. An Experiment in Autotrophic Fermentation: Microbial Oxidation of Hydrogen Sulfide.

    Science.gov (United States)

    Sublette, Kerry L.

    1989-01-01

    Described is an experiment which uses an autotrophic bacterium to anaerobically oxidize hydrogen sulfide to sulfate in a batch-stirred tank reactor. Discusses background information, experimental procedure, and sample results of this activity. (CW)

  20. Hydrogen Sulfide Micro-Sensor for Biomass Fouling Detection Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Hydrogen Sulfide (H2S)is the leading chemical agent causing human fatalities following inhalation exposures. The overall aim of this project is to develop and...

  1. Nanostructured Metal Oxides and Sulfides for Lithium-Sulfur Batteries.

    Science.gov (United States)

    Liu, Xue; Huang, Jia-Qi; Zhang, Qiang; Mai, Liqiang

    2017-02-03

    Lithium-sulfur (Li-S) batteries with high energy density and long cycle life are considered to be one of the most promising next-generation energy-storage systems beyond routine lithium-ion batteries. Various approaches have been proposed to break down technical barriers in Li-S battery systems. The use of nanostructured metal oxides and sulfides for high sulfur utilization and long life span of Li-S batteries is reviewed here. The relationships between the intrinsic properties of metal oxide/sulfide hosts and electrochemical performances of Li-S batteries are discussed. Nanostructured metal oxides/sulfides hosts used in solid sulfur cathodes, separators/interlayers, lithium-metal-anode protection, and lithium polysulfides batteries are discussed respectively. Prospects for the future developments of Li-S batteries with nanostructured metal oxides/sulfides are also discussed.

  2. Selective adsorption of bacteria on sulfide minerals surface

    Institute of Scientific and Technical Information of China (English)

    JIA Chun-yun; WEI De-zhou; LIU Wen-gang; HAN Cong; GAO Shu-ling; WANG Yu-juan

    2008-01-01

    The adsorption of bacteria on sulfide minerals surface was studied, and the selective adsorption mechanism of cells on the sulfide minerals was investigated by means of FTIR, UVS and XPS. The results show that the three strains of bacteria adsorbed more preferentially on pyrite than on other two sulfide minerals surface at neutral and alkaline pH conditions. FTIR and UVS of three strains of bacteria indicate that there are more functional groups on their surface, such as O-H, C=O, N-H, C-O, and the content of saccharide is more than that of protein. The state of every element on sulfide minerals surface was analyzed by XPS. The empty orbital number of electronic shell of metal ions on minerals surface is important in selective adsorption process, and some stable constants of metal coordinates can be used to explain the contribution of some groups in saccharide of cell wall to the selective adsorption.

  3. Oxidation and Precipitation of Sulfide in Sewer Networks

    DEFF Research Database (Denmark)

    Nielsen, A. H.

    wastewater and biofilms of sewer networks was studied in detail with emphasis on determination of process kinetics and stoichiometry. In the water phase, sulfide oxidation may be both chemical and biological and the investigations showed that both processes were of significant importance in the sulfur cycle...... transformations. The experiments indicated that biological sulfide oxidation in the water phase and sulfide oxidation by sewer biofilms produce elemental sulfur under the conditions investigated. The stoichiometry of chemical sulfide oxidation was apparently more complex producing both thiosulfate and sulfate......-workers at Aalborg University for more than a decade. In the basic version, the WATS model simulates changes in dissolved oxygen (DO) and organic fractions of different biodegradability under both aerobic and anaerobic conditions. Evaluation of the model concept has demonstrated that it can be successfully...

  4. Optimization of biological sulfide removal in a CSTR bioreactor.

    Science.gov (United States)

    Roosta, Aliakbar; Jahanmiri, Abdolhossein; Mowla, Dariush; Niazi, Ali; Sotoodeh, Hamidreza

    2012-08-01

    In this study, biological sulfide removal from natural gas in a continuous bioreactor is investigated for estimation of the optimal operational parameters. According to the carried out reactions, sulfide can be converted to elemental sulfur, sulfate, thiosulfate, and polysulfide, of which elemental sulfur is the desired product. A mathematical model is developed and was used for investigation of the effect of various parameters on elemental sulfur selectivity. The results of the simulation show that elemental sulfur selectivity is a function of dissolved oxygen, sulfide load, pH, and concentration of bacteria. Optimal parameter values are calculated for maximum elemental sulfur selectivity by using genetic algorithm as an adaptive heuristic search. In the optimal conditions, 87.76% of sulfide loaded to the bioreactor is converted to elemental sulfur.

  5. Cyclooxygenase (COX) Inhibitors and the Newborn Kidney

    OpenAIRE

    Wei Qi; Smith, Francine G.; Megan L. Lewis; Wade, Andrew W

    2012-01-01

    This review summarizes our current understanding of the role of cyclo-oxygenase inhibitors (COXI) in influencing the structural development as well as the function of the developing kidney. COXI administered either during pregnancy or after birth can influence kidney development including nephronogenesis, and can decrease renal perfusion and ultrafiltration potentially leading to acute kidney injury in the newborn period. To date, which COX isoform (COX-1 or COX-2) plays a more important role...

  6. An eco-friendly oxidation of sulfide compounds

    Indian Academy of Sciences (India)

    RAVINDRA B WAGH; SITARAM H GUND; JAYASHREE M NAGARKAR

    2016-08-01

    An improved green route has been developed for the oxidation of sulfide compounds. Albendazole is converted to ricobendazole or albendazole sulfone using H₂O₂ as an oxidant and H₂O as the solvent. High yields of the corresponding products were obtained by carrying out the reaction at room temperature. This synthetic method is environmentally clean and safe, operationally simple for the oxidation of other benzimidazole anthelmintics and various sulfide compounds.

  7. INVESTIGATIONS ON BIOCHEMICAL PURIFICATION OF GROUND WATER FROM HYDROGEN SULFIDE

    Directory of Open Access Journals (Sweden)

    Yu. P. Sedlukho

    2015-01-01

    Full Text Available The paper considers problems and features of biochemical removal of hydrogen sulfide from ground water. The analysis of existing methods for purification of ground water from hydrogen sulfide has been given in the paper. The paper has established shortcomings of physical and chemical purification of ground water. While using aeration methods for removal of hydrogen sulfide formation of colloidal sulfur that gives muddiness and opalescence to water occurs due to partial chemical air oxidation. In addition to this violation of sulfide-carbonate equilibrium taking place in the process of aeration due to desorption of H2S and CO2, often leads to clogging of degasifier nozzles with formed CaCO3 that causes serious operational problems. Chemical methods require relatively large flow of complex reagent facilities, storage facilities and transportation costs.In terms of hydrogen sulfide ground water purification the greatest interest is given to the biochemical method. Factors deterring widespread application of the biochemical method is its insufficient previous investigation and necessity to execute special research in order to determine optimal process parameters while purifying groundwater of a particular water supply source. Biochemical methods for oxidation of sulfur compounds are based on natural biological processes that ensure natural sulfur cycle. S. Vinogradsky has established a two-stage mechanism for oxidation of hydrogen sulfide with sulfur bacteria (Beggiatoa. The first stage presupposes oxidation of hydrogen sulphide to elemental sulfur which is accumulating in the cytoplasm in the form of globules. During the second stage sulfur bacteria begin to oxidize intracellular sulfur to sulfuric acid due to shortage of hydrogen sulfide.The paper provides the results of technological tests of large-scale pilot plants for biochemical purification of groundwater from hydrogen sulfide in semi-industrial conditions. Dependences of water quality

  8. LUMINESCENCE OF CADMIUM SULFIDE QUANTUM DOTS IN FLUOROPHOSPHATE GLASSES

    OpenAIRE

    Z. O. Lipatova; E. V. Kolobkova; V. A. Aseev

    2015-01-01

    Cadmium sulfide quantum dots are perspective materials in optics, medicine, biology and optoelectronics. Fluorophosphate glasses, doped with cadmium sulfide quantum dots, were examined in the paper. Heat treatment led to the formation of quantum dots with diameters equal to 2.8 nm, 3.0 nm and 3.8 nm. In view of such changes in the quantum dots size the fundamental absorption edge shift and the luminescence band are being displaced to the long wavelengths. Luminescence lifetime has been fou...

  9. Bioavailability and Methylation Potential of Mercury Sulfides in Sediments

    Science.gov (United States)

    2014-08-01

    the aquatic environment is a critical step towards accumulation of this toxic metal in the aquatic food chain. MeHg is produced in the environment...much more abundant than mercury (e.g. iron, aluminum, manganese , titanium, zinc). Nanoparticles and polynuclear clusters of metal sulfides such as...trace metal bioavailability and toxicity has yet to be fully realized. Our findings provide a new approach that may be applied to other metal-sulfide

  10. Sulfide capacity of high alumina blast furnace slags

    Science.gov (United States)

    Shankar, Amitabh; Görnerup, Märten; Seetharaman, S.; Lahiri, A. K.

    2006-12-01

    Sulfide capacities of high alumina blast furnace slags were experimentally determined using the gas-slag equilibration technique. Two different slag systems were considered for the current study, namely, CaO-SiO2-MgO-Al2O3 quaternary and CaO-SiO2-MgO-Al2O3-TiO2 quinary system. The liquid slag was equilibrated with the Ar-CO-CO2-SO2 gas mixture. Experiments were conducted in the temperature range of 1773 to 1873 K. The effects of temperature, basicity, and the MgO and TiO2 contents of slags on sulfide capacity were studied. As expected, sulfide capacity was found to increase with the increase in temperature and basicity. At the higher experimental temperature, titania decreases the sulfide capacity of slag. However, at the lower temperature, there was no significant effect of titania on the sulfide capacity of slag. Sulfide capacity increases with the increase in MgO content of slag if the MgO content is more than 5 pct.

  11. Sulfide oxidation in fluidized bed bioreactor using nylon support material

    Institute of Scientific and Technical Information of China (English)

    Varsha Midha; M K Jha; Apurba Dey

    2012-01-01

    A continuous fluidized bed bioreactor(FBBR)with nylon support particles was used to treat synthetic sulfide wastewater at different hydraulic retention time of 25,50 and 75 min and upflow velocity of 14,17 and 20 m/hr.The effects of upflow velocity,hydraulic retention time and reactor operation time on sulfide oxidation rate were studied using statistical model.Mixed culture obtained from the activated sludge,taken from tannery effluent treatment plant,was used as a source for microorganisms.The diameter and density of the nylon particles were 2-3 mm and 1140 kg/m3,respectively.Experiments were carried out in the reactor at a temperature of(30± 2)℃,at a fixed bed height of 16 cm after the formation of biofilm on the surface of support particles.Biofilm thickness reached(42±3)μm after 15 days from reactor start-up.The sulfide oxidation,sulfate and sulfur formation is examined at all hydraulic retention times and upflow velocities.The results indicated that almost 90%-92% sulfide oxidation was achieved at all hydraulic retention times.Statistical model could explain 94% of the variability and analysis of variance showed that upflow velocity and hydraulic retention time slightly affected the sulfide oxidation rate.The highest sulfide oxidation of 92% with 70% sulfur was obtained at hydraulic retention time of 75 min and upflow velocity of 14 m/hr.

  12. Sulfide oxidation in fluidized bed bioreactor using nylon support material.

    Science.gov (United States)

    Midha, Varsha; Jha, M K; Dey, Apurba

    2012-01-01

    A continuous fluidized bed bioreactor (FBBR) with nylon support particles was used to treat synthetic sulfide wastewater at different hydraulic retention time of 25, 50 and 75 min and upflow velocity of 14, 17 and 20 m/hr. The effects of upflow velocity, hydraulic retention time and reactor operation time on sulfide oxidation rate were studied using statistical model. Mixed culture obtained from the activated sludge, taken from tannery effluent treatment plant, was used as a source for microorganisms. The diameter and density of the nylon particles were 2-3 mm and 1140 kg/m3, respectively. Experiments were carried out in the reactor at a temperature of (30 +/- 2) degrees C, at a fixed bed height of 16 cm after the formation of biofilm on the surface of support particles. Biofilm thickness reached (42 +/- 3) microm after 15 days from reactor start-up. The sulfide oxidation, sulfate and sulfur formation is examined at all hydraulic retention times and upflow velocities. The results indicated that almost 90%-92% sulfide oxidation was achieved at all hydraulic retention times. Statistical model could explain 94% of the variability and analysis of variance showed that upflow velocity and hydraulic retention time slightly affected the sulfide oxidation rate. The highest sulfide oxidation of 92% with 70% sulfur was obtained at hydraulic retention time of 75 min and upflow velocity of 14 m/hr.

  13. Dihydrogen Activation by Titanium Sulfide Complexes

    Science.gov (United States)

    Sweeney, Zachary K.; Polse, Jennifer L.; Bergman*, Robert G.; Andersen*, Richard A.

    2005-01-01

    The titanocene sulfido complex Cp*2Ti(S)py (1, Cp* = pentamethylcyclopentadienyl; py = pyridine) is synthesized by addition of a suspension of S8 to a toluene solution of Cp*2Ti-(CH2CH2) (2) and py. The rate of rotation of the pyridine ligand in solution was determined by 1H NMR spectroscopy, and the structure of 1 was determined by X-ray crystallography. Complex 1 reacts reversibly with dihydrogen to give Cp*2Ti(H)SH (6) and py. Reaction of 1 with HD gives an equilibrium mixture of Cp*2Ti(D)SH and Cp*2Ti(H)SD; H2 and D2 are not formed in this reaction. 1D 1H NMR magnetization transfer spectra and 2D EXSY 1H NMR spectra of 6 in the presence of H2 show that in solution the H2, hydride, and hydrosulfido hydrogen atoms exchange. A four-center mechanism for this exchange is proposed. The EXSY studies show that the Ti–H and S–H hydrogens exchange with each other more rapidly than either of those hydrogens exchanges with external H2. A transient dihydrogen complex intermediate is proposed to explain this observation. The infrared spectrum of 6 shows an absorption assigned to the Ti–H stretching mode at 1591 cm−1 that shifts upon deuteration to 1154 cm−1. Reaction of 1 with trimethylsilane, diethylsilane, or dimethylsilane gives Cp*2-Ti(H)SSiMe3 (7), Cp*2Ti(H)SSiHEt2 (8), or Cp*2Ti(H)SSiHMe2 (9), respectively. The isotope effect for the reaction producing 7 has been measured, and a mechanism is proposed. Treatment of 1 with an additional equivalent of S8 results in the formation of the disulfide Cp*2Ti(S2) (4). Acetylene inserts into the Ti–S bond of 4 to produce the vinyl disulfide complex 5. The structures of 4 and 5 have been determined by X-ray diffraction. Compound 4 reacts with 2 in the presence of py to produce 1. Phosphines react with 4 in the presence of H2 to provide 6 and the corresponding phosphine sulfide. Reaction of hydrogen with 4 gives Cp*2-Ti(SH)2 (3). The reactions of 1 and 4 with dihydrogen provide a model for possible mechanisms of H2

  14. Bio-orthogonal "click-and-release" donation of caged carbonyl sulfide (COS) and hydrogen sulfide (H2S).

    Science.gov (United States)

    Steiger, Andrea K; Yang, Yang; Royzen, Maksim; Pluth, Michael D

    2017-01-24

    Hydrogen sulfide (H2S) is an important biomolecule with high therapeutic potential. Here we leverage the inverse-electron demand Diels-Alder (IEDDA) click reaction between a thiocarbamate-functionalized trans-cyclooctene and a tetrazine to deliver carbonyl sulfide (COS), which is quickly converted to H2S by the uniquitous enzyme carbonic anhydrase (CA), thus providing a new strategy for bio-orthogonal COS/H2S donation.

  15. Hydrogen Sulfide--Mechanisms of Toxicity and Development of an Antidote.

    Science.gov (United States)

    Jiang, Jingjing; Chan, Adriano; Ali, Sameh; Saha, Arindam; Haushalter, Kristofer J; Lam, Wai-Ling Macrina; Glasheen, Megan; Parker, James; Brenner, Matthew; Mahon, Sari B; Patel, Hemal H; Ambasudhan, Rajesh; Lipton, Stuart A; Pilz, Renate B; Boss, Gerry R

    2016-02-15

    Hydrogen sulfide is a highly toxic gas-second only to carbon monoxide as a cause of inhalational deaths. Its mechanism of toxicity is only partially known, and no specific therapy exists for sulfide poisoning. We show in several cell types, including human inducible pluripotent stem cell (hiPSC)-derived neurons, that sulfide inhibited complex IV of the mitochondrial respiratory chain and induced apoptosis. Sulfide increased hydroxyl radical production in isolated mouse heart mitochondria and F2-isoprostanes in brains and hearts of mice. The vitamin B12 analog cobinamide reversed the cellular toxicity of sulfide, and rescued Drosophila melanogaster and mice from lethal exposures of hydrogen sulfide gas. Cobinamide worked through two distinct mechanisms: direct reversal of complex IV inhibition and neutralization of sulfide-generated reactive oxygen species. We conclude that sulfide produces a high degree of oxidative stress in cells and tissues, and that cobinamide has promise as a first specific treatment for sulfide poisoning.

  16. Mitochondria and sulfide: a very old story of poisoning, feeding, and signaling?

    Science.gov (United States)

    Bouillaud, Frédéric; Blachier, François

    2011-07-15

    Sulfide is a molecule with toxicity comparable to that of cyanide. It inhibits mitochondrial cytochrome oxidase at submicromolar concentrations. However, at even lower concentrations, sulfide is a substrate for the mitochondrial electron transport chain in mammals, and is comparable to succinate. This oxidation involves a sulfide quinone reductase. Sulfide is thus oxidized before reaching a toxic concentration, which explains why free sulfide concentrations are very low in mammals, even though sulfide is constantly released as a result of cellular metabolism. It has been suggested that sulfide has signaling properties in mammals like two other gases, NO and CO, which are also cytochrome oxidase inhibitors. The oxidation of sulfide by mitochondria creates further complexity in the description/use of sulfide signaling in mammals. In fact, in the many studies reported in the literature, the sulfide concentrations that have been used were well within the range that affects mitochondrial activity. This review focuses on the relevance of sulfide bioenergetics to sulfide biology and discusses the case of colonocytes, which are routinely exposed to higher sulfide concentrations. Finally, we offer perspectives for future studies on the relationship between the two opposing aspects of this Janus-type molecule, sulfide.

  17. H2S exposure elicits differential expression of candidate genes in fish adapted to sulfidic and non-sulfidic environments.

    Science.gov (United States)

    Tobler, Michael; Henpita, Chathurika; Bassett, Brandon; Kelley, Joanna L; Shaw, Jennifer H

    2014-09-01

    Disentangling the effects of plasticity, genetic variation, and their interactions on organismal responses to environmental stressors is a key objective in ecological physiology. We quantified the expression of five candidate genes in response to hydrogen sulfide (H2S) exposure in fish (Poecilia mexicana, Poeciliidae) from a naturally sulfide-rich environment as well as an ancestral, non-sulfidic population to test for constitutive and environmentally dependent population differences in gene expression patterns. Common garden raised individuals that had never encountered environmental H2S during their lifetime were subjected to short or long term H2S exposure treatments or respective non-sulfidic controls. The expression of genes involved in responses to H2S toxicity (cytochrome c oxidase, vascular endothelial growth factor, and cytochrome P450-2J6), H2S detoxification (sulfide:quinone oxidoreductase), and endogenous H2S production (cystathionine γ lyase) was determined in both gill and liver tissues by real time PCR. The results indicated complex changes in expression patterns that--depending on the gene--not only differed between organs and populations, but also on the type of H2S exposure. Populations differences, both constitutive and H2S exposure dependent (i.e., plastic), in gene expression were particularly evident for sulfide:quinone oxidoreductase, vascular endothelial growth factor, and to a lesser degree for cytochrome P450-2J6. Our study uncovered putatively adaptive modifications in gene regulation that parallel previously documented adaptive changes in phenotypic traits.

  18. Detection of thiol modifications by hydrogen sulfide.

    Science.gov (United States)

    Williams, E; Pead, S; Whiteman, M; Wood, M E; Wilson, I D; Ladomery, M R; Teklic, T; Lisjak, M; Hancock, J T

    2015-01-01

    Hydrogen sulfide (H2S) is an important gasotransmitter in both animals and plants. Many physiological events, including responses to stress, have been suggested to involve H2S, at least in part. On the other hand, numerous responses have been reported following treatment with H2S, including changes in the levels of antioxidants and the activities of transcription factors. Therefore, it is important to understand and unravel the events that are taking place downstream of H2S in signaling pathways. H2S is known to interact with other reactive signaling molecules such as reactive oxygen species (ROS) and nitric oxide (NO). One of the mechanisms by which ROS and NO have effects in a cell is the modification of thiol groups on proteins, by oxidation or S-nitrosylation, respectively. Recently, it has been reported that H2S can also modify thiols. Here we report a method for the determination of thiol modifications on proteins following the treatment with biological samples with H2S donors. Here, the nematode Caenorhabditis elegans is used as a model system but this method can be used for samples from other animals or plants.

  19. Subnanometer Thin β-Indium Sulfide Nanosheets.

    Science.gov (United States)

    Acharya, Shinjita; Sarkar, Suresh; Pradhan, Narayan

    2012-12-20

    Nanosheets are a peculiar kind of nanomaterials that are grown two-dimensionally over a micrometer in length and a few nanometers in thickness. Wide varieties of inorganic semiconductor nanosheets are already reported, but controlling the crystal growth and tuning their thickness within few atomic layers have not been yet explored. We investigate here the parameters that determine the thickness and the formation mechanism of subnanometer thin (two atomic layers) cubic indium sulfide (In2S3) nanosheets. Using appropriate reaction condition, the growth kinetics is monitored by controlling the decomposition rate of the single source precursor of In2S3 as a function of nucleation temperature. The variation in the thickness of the nanosheets along the polar [111] direction has been correlated with the rate of evolved H2S gas, which in turn depends on the rate of the precursor decomposition. In addition, it has been observed that the thickness of the In2S3 nanosheets is related to the nucleation temperature.

  20. Anisotropic Optical Properties of Layered Germanium Sulfide

    CERN Document Server

    Tan, Dezhi; Wang, Feijiu; Mohamed, Nur Baizura; Mouri, Shinichiro; Sandhaya, Koirala; Zhang, Wenjing; Miyauchi, Yuhei; Ohfuchi, Mari; Matsuda, Kazunari

    2016-01-01

    Two-dimensional (2D) layered materials, transition metal dichalcogenides and black phosphorus, have attracted much interest from the viewpoints of fundamental physics and device applications. The establishment of new functionalities in anisotropic layered 2D materials is a challenging but rewarding frontier, owing to their remarkable optical properties and prospects for new devices. Here, we report the anisotropic optical properties of layered 2D monochalcogenide of germanium sulfide (GeS). Three Raman scattering peaks corresponding to the B3g, A1g, and A2g modes with strong polarization dependence are demonstrated in the GeS flakes, which validates polarized Raman spectroscopy as an effective method for identifying the crystal orientation of anisotropic layered GeS. Photoluminescence (PL) is observed with a peak at around 1.66 eV that originates from the direct optical transition in GeS at room temperature. Moreover, determination of the polarization dependent characteristics of the PL and absorption reveals...

  1. Hydrogen Sulfide and Cellular Redox Homeostasis

    Directory of Open Access Journals (Sweden)

    Zhi-Zhong Xie

    2016-01-01

    Full Text Available Intracellular redox imbalance is mainly caused by overproduction of reactive oxygen species (ROS or weakness of the natural antioxidant defense system. It is involved in the pathophysiology of a wide array of human diseases. Hydrogen sulfide (H2S is now recognized as the third “gasotransmitters” and proved to exert a wide range of physiological and cytoprotective functions in the biological systems. Among these functions, the role of H2S in oxidative stress has been one of the main focuses over years. However, the underlying mechanisms for the antioxidant effect of H2S are still poorly comprehended. This review presents an overview of the current understanding of H2S specially focusing on the new understanding and mechanisms of the antioxidant effects of H2S based on recent reports. Both inhibition of ROS generation and stimulation of antioxidants are discussed. H2S-induced S-sulfhydration of key proteins (e.g., p66Shc and Keap1 is also one of the focuses of this review.

  2. Hydrogen Sulfide and Cellular Redox Homeostasis

    Science.gov (United States)

    Xie, Zhi-Zhong; Liu, Yang; Bian, Jin-Song

    2016-01-01

    Intracellular redox imbalance is mainly caused by overproduction of reactive oxygen species (ROS) or weakness of the natural antioxidant defense system. It is involved in the pathophysiology of a wide array of human diseases. Hydrogen sulfide (H2S) is now recognized as the third “gasotransmitters” and proved to exert a wide range of physiological and cytoprotective functions in the biological systems. Among these functions, the role of H2S in oxidative stress has been one of the main focuses over years. However, the underlying mechanisms for the antioxidant effect of H2S are still poorly comprehended. This review presents an overview of the current understanding of H2S specially focusing on the new understanding and mechanisms of the antioxidant effects of H2S based on recent reports. Both inhibition of ROS generation and stimulation of antioxidants are discussed. H2S-induced S-sulfhydration of key proteins (e.g., p66Shc and Keap1) is also one of the focuses of this review. PMID:26881033

  3. Mercury Sulfide Dimorphism in Thioarsenate Glasses.

    Science.gov (United States)

    Kassem, M; Sokolov, A; Cuisset, A; Usuki, T; Khaoulani, S; Masselin, P; Le Coq, D; Neuefeind, J C; Feygenson, M; Hannon, A C; Benmore, C J; Bychkov, E

    2016-06-16

    Crystalline mercury sulfide exists in two drastically different polymorphic forms in different domains of the P,T-diagram: red chain-like insulator α-HgS, stable below 344 °C, and black tetrahedral narrow-band semiconductor β-HgS, stable at higher temperatures. Using pulsed neutron and high-energy X-ray diffraction, we show that these two mercury bonding patterns are present simultaneously in mercury thioarsenate glasses HgS-As2S3. The population and interconnectivity of chain-like and tetrahedral dimorphous forms determine both the structural features and fundamental glass properties (thermal, electronic, etc.). DFT simulations of mercury species and RMC modeling of high-resolution diffraction data provide additional details on local Hg environment and connectivity implying the (HgS2/2)m oligomeric chains (1 ≤ m ≤ 6) are acting as a network former while the HgS4/4-related mixed agglomerated units behave as a modifier.

  4. Drug: D00120 [KEGG MEDICUS

    Lifescience Database Archive (English)

    Full Text Available ctivated form is Sulindac sulfide), active substance: Indometacin [DR:D00141] cyclooxygenase-1 (COX-1) inhib...itor [HSA:5742] [KO:K00509]; cyclooxygenase-2 (COX-2) inhibitor [HSA:5743] [KO:K1...d classification of drugs [BR:br08310] Enzymes Oxidoreductases cyclooxygenase-1 (...COX-1) [HSA:5742] [KO:K00509] Sulindac [ATC:M01AB02] D00120 Sulindac (JP16/USP/INN) cyclooxygenase-2 (COX-2)

  5. The effects of varying humidity on copper sulfide film formation.

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, Thomas Michael; Missert, Nancy A.; Barbour, John Charles; Sullivan, John Patrick; Copeland, Robert Guild; Campin, Michael J. (International Sematech, Austin, TX)

    2004-02-01

    Detailed experiments involving extensive high resolution transmission electron microscopy (TEM) revealed significant microstructural differences between Cu sulfides formed at low and high relative humidity (RH). It was known from prior experiments that the sulfide grows linearly with time at low RH up to a sulfide thickness approaching or exceeding one micron, while the sulfide initially grows linearly with time at high RH then becomes sub-linear at a sulfide thickness less than about 0.2 microns, with the sulfidation rate eventually approaching zero. TEM measurements of the Cu2S morphology revealed that the Cu2S formed at low RH has large sized grains (75 to greater than 150 nm) that are columnar in structure with sharp, abrupt grain boundaries. In contrast, the Cu2S formed at high RH has small equiaxed grains of 20 to 50 nm in size. Importantly, the small grains formed at high RH have highly disordered grain boundaries with a high concentration of nano-voids. Two-dimensional diffusion modeling was performed to determine whether the existence of localized source terms at the Cu/Cu2S interface could be responsible for the suppression of Cu sulfidation at long times at high RH. The models indicated that the existence of static localized source terms would not predict the complete suppression of growth that was observed. Instead, the models suggest that the diffusion of Cu through Cu2S becomes restricted during Cu2S formation at high RH. The leading speculation is that the extensive voiding that exists at grain boundaries in this material greatly reduces the flux of Cu between grains, leading to a reduction in the rate of sulfide film formation. These experiments provide an approach for adding microstructural information to Cu sulfidation rate computer models. In addition to the microstructural studies, new micro-patterned test structures were developed in this LDRD to offer insight into the point defect structure of Cu2S and to permit measurement of surface reaction

  6. Atmospheric measurements of carbonyl sulfide, dimethyl sulfide, and carbon disulfide using the electron capture sulfur detector

    Science.gov (United States)

    Johnson, James E.; Bates, Timothy S.

    1993-01-01

    Measurements of atmospheric dimethyl sulfide (DMS), carbonyl sulfide (COS), and carbon disulfide (CS2) were conducted over the Atlantic Ocean on board the NASA Electra aircraft during the Chemical Instrumentation Test and Evaluation (CITE 3) project using the electron capture sulfur detector (ECD-S). The system employed cryogenic preconcentration of air samples, gas chromatographic separation, catalytic fluorination, and electron capture detection. Samples collected for DMS analysis were scrubbed of oxidants with NaOH impregnated glass fiber filters to preconcentration. The detection limits (DL) of the system for COS, DMS, and CS2 were 5, 5, and 2 ppt, respectively. COS concentrations ranged from 404 to 603 ppt with a mean of 489 ppt for measurements over the North Atlantic Ocean (31 deg N to 41 deg N), and from 395 to 437 ppt with a mean of 419 ppt for measurements over the Tropical Atlantic Ocean (11 deg S to 2 deg N). DMS concentrations in the lower marine boundary layer, below 600-m altitude, ranged from below DL to 150 ppt from flights over the North Atlantic, and from 9 to 104 ppt over the Tropical Atlantic. CS2 concentrations ranged from below DL to 29 ppt over the North Atlantic. Almost all CS2 measurements over the Tropical Atlantic were below DL.

  7. Hydrogen sulfide can inhibit and enhance oxygenic photosynthesis in a cyanobacterium from sulfidic springs.

    Science.gov (United States)

    Klatt, Judith M; Haas, Sebastian; Yilmaz, Pelin; de Beer, Dirk; Polerecky, Lubos

    2015-09-01

    We used microsensors to investigate the combinatory effect of hydrogen sulfide (H2 S) and light on oxygenic photosynthesis in biofilms formed by a cyanobacterium from sulfidic springs. We found that photosynthesis was both positively and negatively affected by H2 S: (i) H2 S accelerated the recovery of photosynthesis after prolonged exposure to darkness and anoxia. We suggest that this is possibly due to regulatory effects of H2 S on photosystem I components and/or on the Calvin cycle. (ii) H2 S concentrations of up to 210 μM temporarily enhanced the photosynthetic rates at low irradiance. Modelling showed that this enhancement is plausibly based on changes in the light-harvesting efficiency. (iii) Above a certain light-dependent concentration threshold H2 S also acted as an inhibitor. Intriguingly, this inhibition was not instant but occurred only after a specific time interval that decreased with increasing light intensity. That photosynthesis is most sensitive to inhibition at high light intensities suggests that H2 S inactivates an intermediate of the oxygen evolving complex that accumulates with increasing light intensity. We discuss the implications of these three effects of H2 S in the context of cyanobacterial photosynthesis under conditions with diurnally fluctuating light and H2 S concentrations, such as those occurring in microbial mats and biofilms. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

  8. Carbonyl sulfide and dimethyl sulfide exchange between lawn and the atmosphere

    Science.gov (United States)

    Geng, Chunmei; Mu, Yujing

    2004-06-01

    The exchange of carbonyl sulfide (COS) between lawn and the atmosphere was investigated by using a static enclosure under natural field conditions. The results indicated that the lawn acted as a sink for atmospheric COS and a source of dimethyl sulfide (DMS). The exchange fluxes of COS and DMS ranged between -3.24 pmol m-2 s-1 and -94.52 pmol m-2 s-1, and between 0 and 3.14 pmol m-2 s-1, respectively. The lawn was capable of continuously absorbing COS in nighttime as well as in daytime. The COS fluxes depended strongly on the ambient COS mixing ratios. The dependency of DMS emission fluxes on temperature was observed in November 2002. Soil also acted as a sink for COS during our study. However, the COS exchange fluxes of the lawn were much higher than that of the soil. The average COS and DMS fluxes were much higher in spring than in autumn and in summer. The daytime vertical profiles of COS also indicated that the lawn acted as a net sink for COS.

  9. Microbial control of hydrogen sulfide production in a porous medium

    Energy Technology Data Exchange (ETDEWEB)

    McInerney, M.J.; Wofford, N.Q. [Univ. of Oklahoma, Norman, OK (United States); Sublette, K.L. [Univ. of Tulsa, OK (United States)

    1996-12-31

    The ability of a sulfide- and glutaraldehyde-tolerant strain of Thiobacillus denitrificans (strain F) to control sulfide production in an experimental system of cores and formation water from the Redfield, Iowa natural gas storage facility was investigated. A stable, sulfide-producing biofilm was established in two separate core systems, one of which was inoculated with strain F, and the other core system (control) was treated in an identical manner, but was not inoculated with strain F. When formation water with 10 mM acetate and 5mM nitrate was injected into both core systems, the effluent sulfide concentrations in the control core system ranged from 200-460 {mu}M. In the test core system inoculated with strain F, the effluent sulfide concentrations were lower, ranging from 70-110 {mu}M. In order to determine whether strain F could control sulfide production under optimal conditions for sulfate-reducing bacteria, the electron donor was changed to lactate, and inorganic nutrients (nitrogen and phosphate sources) were added to the formation water. When nutrient-supplemented formation water with 3.1 mM lactate and 10 mM nitrate was used, the effluent sulfide concentrations of the control core system initially increased to about 3800 pM, and then decreased to about 1100 {mu}M after 5 wk. However, in the test core system inoculated with strain F, the effluent sulfide concentrations were much lower, 160-330 {mu}M. Nitrate consumption (5 mM) and high concentrations (101-1011 cells/mL) of strain F were detected in the test core system. An accumulation of biomass occurred in the influent lines during 2 mo of continuous operation, but only a small increase in injection pressure was observed. These studies showed that inoculation with strain F was needed for effective control of sulfide production, and that significant plugging or loss of injectivity owing to microbial inoculation did not occur. 7 refs., 3 figs., 1 tab.

  10. Species-specific enzymatic tolerance of sulfide toxicity in plant roots.

    Science.gov (United States)

    Martin, Nicole M; Maricle, Brian R

    2015-03-01

    Toxic effects of sulfide come from a poisoning of a number of enzymes, especially cytochrome c oxidase, which catalyzes the terminal step in mitochondrial aerobic respiration. Despite this, some estuarine plants live in sulfide-rich sediments. We hypothesized estuarine and flooding-tolerant species might be more tolerant of sulfide compared to upland species, and this was tested by measures of root cytochrome c oxidase and alcohol dehydrogenase activities in extracts exposed to sulfide. Enzyme activities were measured in 0, 5, 10, 15, and 20 μM sodium sulfide, and compared among 17 species of plants. Activities of alcohol dehydrogenase and cytochrome c oxidase were both reduced by increasing sulfide concentration, but cytochrome c oxidase was more sensitive to sulfide compared to alcohol dehydrogenase. Activities of cytochrome c oxidase were reduced to near zero at 5-10 μM sulfide whereas alcohol dehydrogenase activities were only reduced by about 50% at 10 μM sulfide. All species were sensitive to increasing sulfide, but to different degrees. Cytochrome c oxidase in flooding-sensitive species was decreased to near zero activity at 5 μM sulfide, whereas activities in some flooding-tolerant species were still detectable until 15 μM sulfide. Cytochrome c oxidase activities in some estuarine species were low even in the absence of sulfide, perhaps an adaptation to avoid sulfide vulnerability in their native, sulfide-rich habitat. This illustrates the potent metabolic effects of sulfide, and this is the first demonstration of varying sensitivities of cytochrome c oxidase to sulfide across organisms, making these data of novel importance.

  11. Influence of dissolved organic matter on the complexation of mercury under sulfidic conditions.

    Science.gov (United States)

    Miller, Carrie L; Mason, Robert P; Gilmour, Cynthia C; Heyes, Andrew

    2007-04-01

    The complexation of Hg under sulfidic conditions influences its bioavailability for microbial methylation. Neutral dissolved Hg-sulfide complexes are readily available to Hg-methylating bacteria in culture, and thermodynamic models predict that inorganic Hg-sulfide complexes dominate dissolved Hg speciation under natural sulfidic conditions. However, these models have not been validated in the field. To examine the complexation of Hg in natural sulfidic waters, octanol/water partitioning methods were modified for use under environmentally relevant conditions, and a centrifuge ultrafiltration technique was developed. These techniques demonstrated much lower concentrations of dissolved Hg-sulfide complexes than predicted. Furthermore, the study revealed an interaction between Hg, dissolved organic matter (DOM), and sulfide that is not captured by current thermodynamic models. Whereas Hg forms strong complexes with DOM under oxic conditions, these complexes had not been expected to form in the presence of sulfide because of the stronger affinity of Hg for sulfide relative to its affinity for DOM. The observed interaction between Hg and DOM in the presence of sulfide likely involves the formation of a DOM-Hg-sulfide complex or results from the hydrophobic partitioning of neutral Hg-sulfide complexes into the higher-molecular-weight DOM. An understanding of the mechanism of this interaction and determination of complexation coefficients for the Hg-sulfide-DOM complex are needed to adequately assess how our new finding affects Hg bioavailability, sorption, and flux.

  12. Sulfide Oxidation in the Anoxic Black-Sea Chemocline

    DEFF Research Database (Denmark)

    JØRGENSEN, BB; FOSSING, H.; WIRSEN, CO

    1991-01-01

    -99 m. Oxygen in the water column immediately overlying the sulfide zone was depleted to undetectable levels resulting in a 20-30-m deep intermediate layer of O2- and H2S-free water. Radiotracer studies with S-35-labelled H2S showed that high rates of sulfide oxidation, up to a few micromoles per liter...... per day, occurred in anoxic water at the top of the sulfide zone concurrent with the highest rates of dark CO2 assimilation. The main soluble oxidized products of sulfide were thiosulfate (68-82%) and sulfate. Indirect evidence was presented for the formation of elemental sulfur which accumulated...... that the measured H2S oxidation rates were 4-fold higher than could be explained by the downward flux of organic carbon and too high to balance the availability of electron acceptors such as oxidized iron or manganese. A nitrate maximum at the lower boundary of the O2 zone did not extend down to the sulfide zone....

  13. Solubility and permeation of hydrogen sulfide in lipid membranes.

    Directory of Open Access Journals (Sweden)

    Ernesto Cuevasanta

    Full Text Available Hydrogen sulfide (H(2S is mainly known for its toxicity but has recently been shown to be produced endogenously in mammalian tissues and to be associated with physiological regulatory functions. To better understand the role of biomembranes in modulating its biological distribution and effects; we measured the partition coefficient of H(2S in models of biological membranes. The partition coefficients were found to be 2.1±0.2, 1.9±0.5 and 2.0±0.6 in n-octanol, hexane and dilauroylphosphatidylcholine liposome membranes relative to water, respectively (25°C. This two-fold higher concentration of H(2S in the membrane translates into a rapid membrane permeability, P(m = 3 cm s(-1. We used a mathematical model in three dimensions to gain insight into the diffusion of total sulfide in tissues. This model shows that the sphere of action of sulfide produced by a single cell expands to involve more than 200 neighboring cells, and that the resistance imposed by lipid membranes has a significant effect on the diffusional spread of sulfide at pH 7.4, increasing local concentrations. These results support the role of hydrogen sulfide as a paracrine signaling molecule and reveal advantageous pharmacokinetic properties for its therapeutic applications.

  14. Solubility and permeation of hydrogen sulfide in lipid membranes.

    Science.gov (United States)

    Cuevasanta, Ernesto; Denicola, Ana; Alvarez, Beatriz; Möller, Matías N

    2012-01-01

    Hydrogen sulfide (H(2)S) is mainly known for its toxicity but has recently been shown to be produced endogenously in mammalian tissues and to be associated with physiological regulatory functions. To better understand the role of biomembranes in modulating its biological distribution and effects; we measured the partition coefficient of H(2)S in models of biological membranes. The partition coefficients were found to be 2.1±0.2, 1.9±0.5 and 2.0±0.6 in n-octanol, hexane and dilauroylphosphatidylcholine liposome membranes relative to water, respectively (25°C). This two-fold higher concentration of H(2)S in the membrane translates into a rapid membrane permeability, P(m) = 3 cm s(-1). We used a mathematical model in three dimensions to gain insight into the diffusion of total sulfide in tissues. This model shows that the sphere of action of sulfide produced by a single cell expands to involve more than 200 neighboring cells, and that the resistance imposed by lipid membranes has a significant effect on the diffusional spread of sulfide at pH 7.4, increasing local concentrations. These results support the role of hydrogen sulfide as a paracrine signaling molecule and reveal advantageous pharmacokinetic properties for its therapeutic applications.

  15. Chemical dosing for sulfide control in Australia: An industry survey.

    Science.gov (United States)

    Ganigue, Ramon; Gutierrez, Oriol; Rootsey, Ray; Yuan, Zhiguo

    2011-12-01

    Controlling sulfide (H(2)S) production and emission in sewer systems is critical due to the corrosion and malodour problems that sulfide causes. Chemical dosing is one of the most commonly used measures to mitigate these problems. Many chemicals have been reported to be effective for sulfide control, but the extent of success varies between chemicals and is also dependent on how they are applied. This industry survey aims to summarise the current practice in Australia with the view to assist the water industry to further improve their practices and to identify new research questions. Results showed that dosing is mainly undertaken in pressure mains. Magnesium hydroxide, sodium hydroxide and nitrate are the most commonly used chemicals for sewers with low flows. In comparison, iron salts are preferentially used for sulfide control in large systems. The use of oxygen injection has declined dramatically in the past few years. Chemical dosing is mainly conducted at wet wells and pumping stations, except for oxygen, which is injected into the pipe. The dosing rates are normally linked to the control mechanisms of the chemicals and the dosing locations, with constant or profiled dosing rates usually applied. Finally, key opportunities for improvement are the use of mathematical models for the selection of chemicals and dosing locations, on-line dynamic control of the dosing rates and the development of more cost-effective chemicals for sulfide control.

  16. Do garlic-derived allyl sulfides scavenge peroxyl radicals?

    Science.gov (United States)

    Amorati, Riccardo; Pedulli, Gian Franco

    2008-03-21

    The chain-breaking antioxidant activities of two garlic-derived allyl sulfides, i.e. diallyl disulfide (1), the main component of steam-distilled garlic oil, and allyl methyl sulfide (3) were evaluated by studying the thermally initiated autoxidation of cumene or styrene in their presence. Although the rate of cumene oxidation was reduced by addition of both 1 and 3, the dependence on the concentration of the two sulfides could not be explained on the basis of the classic antioxidant mechanism as with phenolic antioxidants. The rate of oxidation of styrene, on the other hand, did not show significant changes upon addition of either 1 or 3. This unusual behaviour was explained in terms of the co-oxidant effect, consisting in the decrease of the autoxidation rate of a substrate forming tertiary peroxyl radicals (i.e. cumene) upon addition of little amounts of a second oxidizable substrate giving rise instead to secondary peroxyl radicals. The relevant rate constants for the reaction of ROO(.) with 1 and 3 were measured as 1.6 and 1.0 M(-1) s(-1), respectively, fully consistent with the H-atom abstraction from substituted sulfides. It is therefore concluded that sulfides 1 and 3 do not scavenge peroxyl radicals and therefore cannot be considered chain-breaking antioxidants.

  17. Electrical properties of seafloor massive sulfides

    Science.gov (United States)

    Spagnoli, Giovanni; Hannington, Mark; Bairlein, Katharina; Hördt, Andreas; Jegen, Marion; Petersen, Sven; Laurila, Tea

    2016-06-01

    Seafloor massive sulfide (SMS) deposits are increasingly seen as important marine metal resources for the future. A growing number of industrialized nations are involved in the surveying and sampling of such deposits by drilling. Drill ships are expensive and their availability can be limited; seabed drill rigs are a cost-effective alternative and more suitable for obtaining cores for resource evaluation. In order to achieve the objectives of resource evaluations, details are required of the geological, mineralogical, and physical properties of the polymetallic deposits and their host rocks. Electrical properties of the deposits and their ore minerals are distinct from their unmineralized host rocks. Therefore, the use of electrical methods to detect SMS while drilling and recovering drill cores could decrease the costs and accelerate offshore operations by limiting the amount of drilling in unmineralized material. This paper presents new data regarding the electrical properties of SMS cores that can be used in that assessment. Frequency-dependent complex electrical resistivity in the frequency range between 0.002 and 100 Hz was examined in order to potentially discriminate between different types of fresh rocks, alteration and mineralization. Forty mini-cores of SMS and unmineralized host rocks were tested in the laboratory, originating from different tectonic settings such as the intermediate-spreading ridges of the Galapagos and Axial Seamount, and the Pacmanus back-arc basin. The results indicate that there is a clear potential to distinguish between mineralized and non-mineralized samples, with some evidence that even different types of mineralization can be discriminated. This could be achieved using resistivity magnitude alone with appropriate rig-mounted electrical sensors. Exploiting the frequency-dependent behavior of resistivity might amplify the differences and further improve the rock characterization.

  18. Hydrogen sulfide and nervous system regulation

    Institute of Scientific and Technical Information of China (English)

    ZHOU Cheng-fang; TANG Xiao-qing

    2011-01-01

    Objective This review discusses the current status and progress in studies on the roles of hydrogen sulfide (H2S) in regulation of neurotoxicity,neuroprotection,and neuromodulator,as well as its therapeutic potential for neurodegenerative disorders.Data sources The data used in this review were mainly from Medline and PubMed published in English from 2001 to August 2011.The search terms were “hydrogen sulfide”,“neuron”,and “neurodegenerative disorders”.Study selection Articles regarding the regulation of neuronal function,the protection against neuronal damage and neurological diseases,and their possible cellular and molecular mechanisms associated with H2S were selected.Results The inhibited generation of endogenous H2S is implicated in 1-methy-4-phenylpyridinium ion,6-OHDA,and homocysteine-triggered neurotoxicity.H2S elicits neuroprotection in Alzheimer's disease and Parkinson's disease models as well as protecting neurons against oxidative stress,ischemia,and hypoxia-induced neuronal death.H2S offers anti-oxidant,anti-inflammatory and anti-apoptotic effects,as well as activates ATP-sensitive potassium channels and cystic fibrosis transmembrane conductance regulator Cl- channels.H2S regulates the long-term potentiation (LTP) and GABAB receptors in the hippocampus,as well as intracellular calcium and pH homeostasis in neurons and glia cells.Conclusions These articles suggest that endogenous H2S may regulate the toxicity of neurotoxin.H2S not only acts as a neuroprotectant but also serves as a novel neuromodulator.

  19. Interaction of hydrogen sulfide with ion channels.

    Science.gov (United States)

    Tang, Guanghua; Wu, Lingyun; Wang, Rui

    2010-07-01

    1. Hydrogen sulfide (H(2)S) is a signalling gasotransmitter. It targets different ion channels and receptors, and fulfils its various roles in modulating the functions of different systems. However, the interaction of H(2)S with different types of ion channels and underlying molecular mechanisms has not been reviewed systematically. 2. H(2)S is the first identified endogenous gaseous opener of ATP-sensitive K(+) channels in vascular smooth muscle cells. Through the activation of ATP-sensitive K(+) channels, H(2)S lowers blood pressure, protects the heart from ischemia and reperfusion injury, inhibits insulin secretion in pancreatic beta cells, and exerts anti-inflammatory, anti-nociceptive and anti-apoptotic effects. 3. H(2)S inhibited L-type Ca(2+) channels in cardiomyocytes but stimulated the same channels in neurons, thus regulating intracellular Ca(2+) levels. H(2)S activated small and medium conductance K(Ca) channels but its effect on BK(Ca) channels has not been consistent. 4. H(2)S-induced hyperalgesia and pro-nociception seems to be related to the sensitization of both T-type Ca(2+) channels and TRPV(1) channels. The activation of TRPV(1) and TRPA(1) by H(2)S is believed to result in contraction of nonvascular smooth muscles and increased colonic mucosal Cl(-) secretion. 5. The activation of Cl(-) channel by H(2)S has been shown as a protective mechanism for neurons from oxytosis. H(2)S also potentiates N-methyl-d-aspartic acid receptor-mediated currents that are involved in regulating synaptic plasticity for learning and memory. 6. Given the important modulatory effects of H(2)S on different ion channels, many cellular functions and disease conditions related to homeostatic control of ion fluxes across cell membrane should be re-evaluated.

  20. Hydrogen sulfide: metabolism, biological and medical role

    Directory of Open Access Journals (Sweden)

    N. V. Zaichko

    2014-10-01

    Full Text Available Hydrogen sulfide (H2S is a signaling molecule that is actively synthesized in the tissues and is involved in the regulation of vascular tone, neuromodulation, cytoprotection, inflammation and apoptosis. In recent years, new data on animal and human H2S metabolism and function under the effect of various endogenous and exogenous factors, including drugs were collected. This review is provided to introduce generalized information about the main and alternative H2S metabolism and regulation, peculiarities of transport, signaling, biological role and participation in pathogenesis. Submitted data describe H2S content and activity of H2S-synthesizing enzymes in different organs, H2S effect on blood coagulation and platelet aggregation based on our research results. The working classification of H2S metabolism modulators, which are used in biology and medicine, is proposed: 1 agents that increase H2S content in tissues (inorganic and organic H2S donors; H2S-synthesizing enzymes substrates and their derivatives, H2S-releasing drugs; agents that contain H2S-synthesizing enzymes cofactors and activators, agents that inhibit H2S utilization; 2 agents that reduce H2S content in tissues (specific and nonspecific inhibitors of H2S-synthesizing enzymes, 3 agents with uncertain impact on H2S metabolism (some medicines. It was demonstrated that vitamin-microelement and microelement complexes with H2S-synthesizing enzymes cofactors and activators represent a promising approach for H2S content correction in tissues.

  1. Simultaneous removal of sulfide, nitrate and acetate under denitrifying sulfide removal condition: Modeling and experimental validation

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Xijun; Chen, Chuan; Wang, Aijie; Guo, Wanqian; Zhou, Xu [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Lee, Duu-Jong, E-mail: djlee@ntu.edu.tw [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Department of Chemical Engineering, National Taiwan University, Taipei 106, Taiwan (China); Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan (China); Ren, Nanqi, E-mail: rnq@hit.edu.cn [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Chang, Jo-Shu [Research Center for Energy Technology and Strategy, National Cheng Kung University, Tainan, Taiwan (China)

    2014-01-15

    Graphical abstract: Model evaluation applied to case study 1: (A-G) S{sup 2−}, NO{sub 3}{sup −}-N, NO{sub 2}{sup −}-N, and Ac{sup −}-C profiles under initial sulfide concentrations of 156.2 (A), 539 (B), 964 (C), 1490 (D), 342.7 (E), 718 (F), and 1140.7 (G) mg L{sup −1}. The solid line represents simulated result and scatter represents experimental result. -- Highlights: • This work developed a mathematical model for DSR process. • Kinetics of sulfur–nitrogen–carbon and interactions between denitrifiers were studied. • Kinetic parameters of the model were estimated via data fitting. • The model described kinetic behaviors of DSR processes over wide parametric range. -- Abstract: Simultaneous removal of sulfide (S{sup 2−}), nitrate (NO{sub 3}{sup −}) and acetate (Ac{sup −}) under denitrifying sulfide removal process (DSR) is a novel biological wastewater treatment process. This work developed a mathematical model to describe the kinetic behavior of sulfur–nitrogen–carbon and interactions between autotrophic denitrifiers and heterotrophic denitrifiers. The kinetic parameters of the model were estimated via data fitting considering the effects of initial S{sup 2−} concentration, S{sup 2−}/NO{sub 3}{sup −}-N ratio and Ac{sup −}-C/NO{sub 3}{sup −}-N ratio. Simulation supported that the heterotrophic denitratation step (NO{sub 3}{sup −} reduction to NO{sub 2}{sup −}) was inhibited by S{sup 2−} compared with the denitritation step (NO{sub 2}{sup −} reduction to N{sub 2}). Also, the S{sup 2−} oxidation by autotrophic denitrifiers was shown two times lower in rate with NO{sub 2}{sup −} as electron acceptor than that with NO{sub 3}{sup −} as electron acceptor. NO{sub 3}{sup −} reduction by autotrophic denitrifiers occurs 3–10 times slower when S{sup 0} participates as final electron donor compared to the S{sup 2−}-driven pathway. Model simulation on continuous-flow DSR reactor suggested that the adjustment of

  2. Thermodynamics of Complex Sulfide Inclusion Formation in Ca-Treated Al-Killed Structural Steel

    Science.gov (United States)

    Guo, Yin-tao; He, Sheng-ping; Chen, Gu-jun; Wang, Qian

    2016-08-01

    Controlling the morphology of the sulfide inclusion is of vital importance in enhancing the properties of structural steel. Long strip-shaped sulfides in hot-rolled steel can spherize when, instead of the inclusion of pure single-phase MnS, the guest is a complex sulfide, such as an oxide-sulfide duplex and a solid-solution sulfide particle. In this study, the inclusions in a commercial rolled structural steel were investigated. Spherical and elongated oxide-sulfide duplex as well as single-phase (Mn,Ca)S solid solution inclusions were observed in the steel. A thermodynamic equilibrium between the oxide and sulfide inclusions was proposed to understand the oxide-sulfide duplex inclusion formation. Based on the equilibrium solidification principle, thermodynamic discussions on inclusion precipitation during the solidification process were performed for both general and resulfurized structural steel. The predicted results of the present study agreed well with the experimental ones.

  3. Mechanism of sulfide effect on viscosity of HPAM polymer solution

    Institute of Scientific and Technical Information of China (English)

    康万利; 周阳; 王志伟; 孟令伟; 刘述忍; 白宝君

    2008-01-01

    The effect of sulfide on HPAM solution viscosity was studied using BROOKFIELD DV-II viscometer,and the interaction mechanism was discussed.The HPAM solution viscosity was investigated through fully reducing sulfide by the addition of hydrogen peroxide oxidation,and the mechanism of increasing polymer viscosity was investigated.The experimental results also show that there is a critical concentration of 15 mg/L.Below it,the loss rate of HPAM solution viscosity increases more rapidly,but becomes slowly above the critical concentration.A theoretical guidance for oilfields to prepare polymer solution using sewage-water by eliminating sulfide,and it is also importance to prepare polymer solution using sewage-water and save fresh water.

  4. Metal sulfide electrodes and energy storage devices thereof

    Energy Technology Data Exchange (ETDEWEB)

    Chiang, Yet-Ming; Woodford, William Henry; Li, Zheng; Carter, W. Craig

    2017-02-28

    The present invention generally relates to energy storage devices, and to metal sulfide energy storage devices in particular. Some aspects of the invention relate to energy storage devices comprising at least one flowable electrode, wherein the flowable electrode comprises an electroactive metal sulfide material suspended and/or dissolved in a carrier fluid. In some embodiments, the flowable electrode further comprises a plurality of electronically conductive particles suspended and/or dissolved in the carrier fluid, wherein the electronically conductive particles form a percolating conductive network. An energy storage device comprising a flowable electrode comprising a metal sulfide electroactive material and a percolating conductive network may advantageously exhibit, upon reversible cycling, higher energy densities and specific capacities than conventional energy storage devices.

  5. Altered Sulfide (H2S) Metabolism in Ethylmalonic Encephalopathy

    Science.gov (United States)

    Tiranti, Valeria; Zeviani, Massimo

    2013-01-01

    Hydrogen sulfide (sulfide, H2S) is a colorless, water-soluble gas with a typical smell of rotten eggs. In the past, it has been investigated for its role as a potent toxic gas emanating from sewers and swamps or as a by-product of industrial processes. At high concentrations, H2S is a powerful inhibitor of cytochrome c oxidase; in trace amounts, it is an important signaling molecule, like nitric oxide (NO) and carbon monoxide (CO), together termed “gasotransmitters.” This review will cover the physiological role and the pathogenic effects of H2S, focusing on ethylmalonic encephalopathy, a human mitochondrial disorder caused by genetic abnormalities of sulfide metabolism. We will also discuss the options that are now conceivable for preventing genetically driven chronic H2S toxicity, taking into account that a complete understanding of the physiopathology of H2S has still to be achieved. PMID:23284046

  6. Altered sulfide (H(2)S) metabolism in ethylmalonic encephalopathy.

    Science.gov (United States)

    Tiranti, Valeria; Zeviani, Massimo

    2013-01-01

    Hydrogen sulfide (sulfide, H(2)S) is a colorless, water-soluble gas with a typical smell of rotten eggs. In the past, it has been investigated for its role as a potent toxic gas emanating from sewers and swamps or as a by-product of industrial processes. At high concentrations, H(2)S is a powerful inhibitor of cytochrome c oxidase; in trace amounts, it is an important signaling molecule, like nitric oxide (NO) and carbon monoxide (CO), together termed "gasotransmitters." This review will cover the physiological role and the pathogenic effects of H(2)S, focusing on ethylmalonic encephalopathy, a human mitochondrial disorder caused by genetic abnormalities of sulfide metabolism. We will also discuss the options that are now conceivable for preventing genetically driven chronic H(2)S toxicity, taking into account that a complete understanding of the physiopathology of H(2)S has still to be achieved.

  7. Investigation of chemical suppressants for inactivation of sulfide ores

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In order to investigate the effective control method of spontaneous combustion in the mining of sulfide ore deposits, This paper presents the testing results of several selected chemicals (water glass, calcium chloride, calcium oxide, magnesium oxide and their composites) as oxidation suppressants for sulfide ores. A weight increment scaling method was used to measure suppressant performance, and this method proved to be accurate, simple and convenient. Based on a large number of experiments, the test results show that four types of chemical mixtures demonstrate a good performance in reducing the oxidation rate of seven active sulfide ore samples by up to 27% to 100% during an initial 76 d period. The mixtures of water glass mixed with calcium chloride and magnesium oxide mixed with calcium chloride can also act as fire suppressants when used with fire sprinkling systems.

  8. Conspicuous veils formed by vibrioid bacteria on sulfidic marine sediment

    DEFF Research Database (Denmark)

    Thar, Roland Matthias; Kühl, Michael

    2002-01-01

    We describe the morphology and behavior of a hitherto unknown bacterial species that forms conspicuous veils (typical dimensions, 30 by 30 mm) on sulfidic marine sediment. The new bacteria were enriched on complex sulfidic medium within a benthic gradient chamber in oxygen-sulfide countergradients......, but the bacteria have so far not been isolated in pure culture, and a detailed characterization of their metabolism is still lacking. The bacteria are colorless, gram-negative, and vibrioid-shaped (1.3- to 2.5- by 4- to 10-µm) cells that multiply by binary division and contain several spherical inclusions of poly......, forming a cohesive whitish veil at the oxic-anoxic interface. Bacteria attached to the veil kept rotating and adapted their stalk lengths dynamically to changing oxygen concentrations. The joint action of rotating bacteria on the veil induced a homogeneous water flow from the oxic water region toward...

  9. Extraction of Nanosized Cobalt Sulfide from Spent Hydrocracking Catalyst

    Directory of Open Access Journals (Sweden)

    Samia A. Kosa

    2013-01-01

    Full Text Available The processes used for the extraction of metals (Co, Mo, and Al from spent hydrotreating catalysts were investigated in this study. A detailed mechanism of the metal extraction process is described. Additionally, a simulation study was performed to understand the sulfidizing mechanism. The suggested separation procedure was effective and achieved an extraction of approximately 80–90%. In addition, the sulfidization mechanism was identified. This sulfidizing process for Co was found to involve an intermediate, the structure of which was proposed. This proposed intermediate was confirmed through simulations. Moreover, the activities of the spent and the regenerated catalyst were examined in the cracking of toluene. The modification of the spent catalyst through the use of different iron oxide loadings improved the catalytic activity.

  10. Vegetation successfully prevents oxidization of sulfide minerals in mine tailings.

    Science.gov (United States)

    Li, Yang; Sun, Qingye; Zhan, Jing; Yang, Yang; Wang, Dan

    2016-07-15

    The oxidization of metal sulfide in tailings causes acid mine drainage. However, it remains unclear whether vegetation prevents the oxidization of metal sulfides. The oxidization characteristics and microbial indices of the tailings in the presence of various plant species were investigated to explore the effects of vegetation on the oxidization of sulfide minerals in tailings. The pH, reducing sulfur, free iron oxides (Fed), chemical oxygen consumption (COC) and biological oxygen consumption (BOC) were measured. Key iron- and sulfur-oxidizing bacteria (Acidithiobacillus spp., Leptospirillum spp. and Thiobacillus spp.) were quantified using real-time PCR. The results indicate that vegetation growing on tailings can effectively prevent the oxidization of sulfide minerals in tailings. A higher pH and reducing-sulfur content and lower Fed were observed in the 0-30 cm depth interval in the presence of vegetation compared to bare tailings (BT). The COC gradually decreased with depth in all of the soil profiles; specifically, the COC rapidly decreased in the 10-20 cm interval in the presence of vegetation but gradually decreased in the BT profiles. Imperata cylindrica (IC) and Chrysopogon zizanoides (CZ) profiles contained the highest BOC in the 10-20 cm interval. The abundance of key iron- and sulfur-oxidizing bacteria in the vegetated tailings were significantly lower than in the BT; in particular, IC was associated with the lowest iron- and sulfur-oxidizing bacterial abundance. In conclusion, vegetation successfully prevented the oxidization of sulfide minerals in the tailings, and Imperata cylindrica is the most effective in reducing the number of iron- and sulfur-oxidizing bacteria and helped to prevent the oxidization of sulfide minerals in the long term. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Morphology and thermal studies of zinc sulfide and cadmium sulfide nanoparticles in polyvinyl alcohol matrix

    Energy Technology Data Exchange (ETDEWEB)

    Osuntokun, Jejenija; Ajibade, Peter A., E-mail: pajibade@ufh.ac.za

    2016-09-01

    Zn(II) and Cd(II) metal complexes of 1-cyano-1-carboethoxyethylene-2,2-dithiolato–κS,S’–bis (N,N-dimethylthiourea–κS) have been synthesized and characterized with analytical and spectroscopic techniques. The complexes were thermolysed in hexadecylamine at 200 °C to prepare ZnS and CdS nanoparticles. The nanoparticles were characterized with scanning electron microscope (SEM), transmission electron microscope (TEM), and powder X-ray diffraction (p-XRD). TEM images showed spherically shaped nanoparticles, whose sizes are in the range 4.33–7.21 nm for ZnS and 4.95–7.7 nm CdS respectively and XRD confirmed cubic crystalline phases for the nanoparticles. The optical band gap energy evaluated from the absorption spectra are 2.88 eV (430 nm) and 2.81 eV (440 nm) for the ZnS and CdS nanoparticles respectively. The as-prepared metal sulfide nanoparticles were further incorporated into polyvinyl alcohol (PVA) to give ZnS/PVA and CdS/PVA composites. The polymer nanocomposites were studied to investigate their morphology and thermal properties relative to the pure PVA. XRD diffractions indicated that the crystalline phases of the nanoparticles and the sizes in PVA matrices remained unaltered. Infra-red spectra studies revealed interactions between the PVA and the metal sulfide nanoparticles and TGA studies show that the ZnS/PVA and CdS/PVA nanocomposites exhibit better thermal stability than the pure PVA.

  12. Morphology and thermal studies of zinc sulfide and cadmium sulfide nanoparticles in polyvinyl alcohol matrix

    Science.gov (United States)

    Osuntokun, Jejenija; Ajibade, Peter A.

    2016-09-01

    Zn(II) and Cd(II) metal complexes of 1-cyano-1-carboethoxyethylene-2,2-dithiolato-κS,S'-bis(N,N-dimethylthiourea-κS) have been synthesized and characterized with analytical and spectroscopic techniques. The complexes were thermolysed in hexadecylamine at 200 °C to prepare ZnS and CdS nanoparticles. The nanoparticles were characterized with scanning electron microscope (SEM), transmission electron microscope (TEM), and powder X-ray diffraction (p-XRD). TEM images showed spherically shaped nanoparticles, whose sizes are in the range 4.33-7.21 nm for ZnS and 4.95-7.7 nm CdS respectively and XRD confirmed cubic crystalline phases for the nanoparticles. The optical band gap energy evaluated from the absorption spectra are 2.88 eV (430 nm) and 2.81 eV (440 nm) for the ZnS and CdS nanoparticles respectively. The as-prepared metal sulfide nanoparticles were further incorporated into polyvinyl alcohol (PVA) to give ZnS/PVA and CdS/PVA composites. The polymer nanocomposites were studied to investigate their morphology and thermal properties relative to the pure PVA. XRD diffractions indicated that the crystalline phases of the nanoparticles and the sizes in PVA matrices remained unaltered. Infra-red spectra studies revealed interactions between the PVA and the metal sulfide nanoparticles and TGA studies show that the ZnS/PVA and CdS/PVA nanocomposites exhibit better thermal stability than the pure PVA.

  13. The Sulfide Capacity of Iron Oxide-Rich Slags

    Science.gov (United States)

    Motlagh, M.

    1988-03-01

    The relationship between the sulfide capacity of slags rich in iron oxide and the sulfur partition ratio between the metal and slag is strongly related to the slag's iron oxide concentration. For slags containing little or no lime, this relationship is linear for a constant concentration of iron oxide in the slag. The effect of silica on changes in the sulfide capacity of slags rich in iron oxide is similar to that of basic steel-making slags, particularly at low activity of silica in slag.

  14. Carbonyl Sulfides as Possible Intermediates in the Photolysis of Oxathiiranes

    DEFF Research Database (Denmark)

    Carlsen, Lars; Snyder, J. P.; Holm, A.

    1981-01-01

    of sulfine to ketone via the oxathiirane and the subsequent blue intermediate implies the absence of triplet and biradical singlet transients. The unknown carbonyl sulfide functionality, R2C&z.dbnd;O&z.dbnd;S, thereby emerges as a strong candidate for producing the visible absorption. Comparison of the wave...... functions for CH2&z.dbnd;S&z.dbnd;O and CH2&z.dbnd;O&z.dbnd;S arising from MNDO limited CI geometry optimizations leads to the conclusion that the carbonyl sulfide structure is best described as a zwitterion rather than as a singlet biradical. The failure to observe cycloaddition products between the blue...

  15. Experimental constraints on gold and silver solubility in iron sulfides

    Energy Technology Data Exchange (ETDEWEB)

    Pal' yanova, Galina [Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, 3, Koptyuga, Novosibirsk, 630090 (Russian Federation); Novosibirsk State University, Russia, 2, Pirogova, Novosibirsk, 630090 (Russian Federation); Mikhlin, Yuri [Institute of Chemistry and Chemical Technology, Siberian Branch of the Russian Academy of Sciences, Akademgorodok, 50/24, Krasnoyarsk, 660036 (Russian Federation); Kokh, Konstantin, E-mail: k.a.kokh@gmail.com [Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, 3, Koptyuga, Novosibirsk, 630090 (Russian Federation); Novosibirsk State University, Russia, 2, Pirogova, Novosibirsk, 630090 (Russian Federation); Siberian Physical–Technical Institute of Tomsk State University, 1, Novosobornaya, Tomsk, 634050 (Russian Federation); Karmanov, Nick [Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, 3, Koptyuga, Novosibirsk, 630090 (Russian Federation); Seryotkin, Yurii [Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, 3, Koptyuga, Novosibirsk, 630090 (Russian Federation); Novosibirsk State University, Russia, 2, Pirogova, Novosibirsk, 630090 (Russian Federation)

    2015-11-15

    Experiments were performed to determine crystallization of Fe,S-melts (pyriti≿ and troilitic with molar ratio S/Fe ratios of 2 and 1, respectively) containing traces of gold and silver at (Ag/Au){sub wt} ratios varying from 10 to 0.1. The solid products were studied by optical microscopy, scanning electron microscopy, X-ray powder diffraction (XRD), microprobe analysis, and X-ray photoelectron spectroscopy (XPS) in order to reveal the concentration limits of “invisible” gold and silver in magmatic iron sulfides, and to determine the influence of sulfur on forms of precious metals in the Fe–S system with different Ag/Au ratios. Au–Ag phases do not form inclusions but instead concentrate on the grain boundaries in the synthetic pyrrhotite and troilite, while pyrite comprises micro- (1–5 μm) and macroinclusions of Au–Ag alloys and Au–Ag sulfides. In “pyriti≿” systems, the fineness of alloys increases from 650 to 970‰ and the composition of sulfides changes from acanthite (Ag{sub 2}S) to uytenbogaardtite (Ag{sub 3}AuS{sub 2}) and petrovskaite (AgAuS) as the Ag/Au ratio decreases. The concentrations of “invisible” precious metals revealed in troilite were 0.040 ± 0.013 wt.% Au and 0.079 ± 0.016 wt.% Ag. Measured concentrations in pyrite and pyrrhotite were <0.024 wt.% Au and <0.030 wt.% Ag. The surface layers of iron sulfides probed with XPS were enriched in the precious metals, and in silver relative to gold, especially in the systems with Fe/S = 1, probably, due to depletion of the metallic alloy surfaces with gold. Au- and Ag-bearing iron sulfides crystallized primarily from melts may be the source of redeposited phases in hydrothermal and hypergene processes. - Highlights: • The samples of Fe–S–Au–Ag system were synthesized. • Coupled solubility of gold and silver in iron sulfides was specified. • Ag–Au inclusions on surfaces of iron sulfides are likely to be enriched in silver. • Au–Ag sulfides can exist along with

  16. Altered Sulfide (H2S) Metabolism in Ethylmalonic Encephalopathy

    OpenAIRE

    2013-01-01

    Hydrogen sulfide (sulfide, H2S) is a colorless, water-soluble gas with a typical smell of rotten eggs. In the past, it has been investigated for its role as a potent toxic gas emanating from sewers and swamps or as a by-product of industrial processes. At high concentrations, H2S is a powerful inhibitor of cytochrome c oxidase; in trace amounts, it is an important signaling molecule, like nitric oxide (NO) and carbon monoxide (CO), together termed “gasotransmitters.” This review will cover th...

  17. A FRET enzyme-based probe for monitoring hydrogen sulfide.

    Science.gov (United States)

    Strianese, Maria; Palm, Gottfried J; Milione, Stefano; Kühl, Olaf; Hinrichs, Winfried; Pellecchia, Claudio

    2012-11-05

    Fluorescently labeled cobalt peptide deformylase (Co-PDF) can be efficiently used as a fluorescence-resonance-energy-transfer-based sensing device for hydrogen sulfide (H(2)S). The proof of concept of our sensor system is substantiated by spectroscopic, structural, and theoretical results. Monohydrogen sulfide coordination to Co-PDF and Ni-PDF was verified by X-ray crystallography. Density functional theory calculations were performed to gain insight into the characteristics of the coordination adduct between H(2)S and the cobalt cofactor in Co-PDF.

  18. Carbonyl Sulfides as Possible Intermediates in the Photolysis of Oxathiiranes

    DEFF Research Database (Denmark)

    Carlsen, Lars; Snyder, J. P.; Holm, A.

    1981-01-01

    of sulfine to ketone via the oxathiirane and the subsequent blue intermediate implies the absence of triplet and biradical singlet transients. The unknown carbonyl sulfide functionality, R2C&z.dbnd;O&z.dbnd;S, thereby emerges as a strong candidate for producing the visible absorption. Comparison of the wave...... functions for CH2&z.dbnd;S&z.dbnd;O and CH2&z.dbnd;O&z.dbnd;S arising from MNDO limited CI geometry optimizations leads to the conclusion that the carbonyl sulfide structure is best described as a zwitterion rather than as a singlet biradical. The failure to observe cycloaddition products between the blue...

  19. High conducting oxide--sulfide composite lithium superionic conductor

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Chengdu; Rangasamy, Ezhiylmurugan; Dudney, Nancy J.; Keum, Jong Kahk; Rondinone, Adam Justin

    2017-01-17

    A solid electrolyte for a lithium-sulfur battery includes particles of a lithium ion conducting oxide composition embedded within a lithium ion conducting sulfide composition. The lithium ion conducting oxide composition can be Li.sub.7La.sub.3Zr.sub.2O.sub.12 (LLZO). The lithium ion conducting sulfide composition can be .beta.-Li.sub.3PS.sub.4 (LPS). A lithium ion battery and a method of making a solid electrolyte for a lithium ion battery are also disclosed.

  20. Identifying the Prospective Area of Sulfide Groundwater within the Area of Palvantash Oil and Gas Deposit

    Directory of Open Access Journals (Sweden)

    M. R. Zhurayev

    2014-03-01

    Full Text Available This paper describes the methodology of prospecting for sulfide groundwater in the area of Palvantash oil fields. In result of study allowed determining the favorable conditions for the sulfide waters formation, and mapping the areas of different sulfide water concentration. The relatively permeable areas were established and the water borehole positions were recommended.

  1. 76 FR 69136 - Hydrogen Sulfide; Community Right-to-Know Toxic Chemical Release Reporting

    Science.gov (United States)

    2011-11-08

    ... AGENCY 40 CFR Part 372 RIN 2025-AA27 Hydrogen Sulfide; Community Right-to-Know Toxic Chemical Release... hydrogen sulfide and methyl mercaptan found at 40 CFR 372.65. The document published in the Federal... requirements for only hydrogen sulfide. The Office of the Federal Register mistakenly lifted the stay of...

  2. Sulfide-iron interactions in domestic wastewater from a gravity sewer

    NARCIS (Netherlands)

    Nielsen, A.H.; Lens, P.N.L.; Vollertsen, J.; Hvitved-Jacobsen, Th.

    2005-01-01

    Interactions between iron and sulfide in domestic wastewater from a gravity sewer were investigated with particular emphasis on redox cycling of iron and iron sulfide formation. The concentration ranges of iron and total sulfide in the experiments were 0.4-5.4 mg Fe L-1 and 0-5.1 mg S L-1, respectiv

  3. SULFIDE OXIDATION UNDER OXYGEN LIMITATION BY A THIOBACILLUS-THIOPARUS ISOLATED FROM A MARINE MICROBIAL MAT

    NARCIS (Netherlands)

    VANDENENDE, FP; VANGEMERDEN, H

    1993-01-01

    The colorless sulfur bacterium Thiobacillus thioparus T5, isolated from a marine microbial mat, was grown in continuous culture under conditions ranging from sulfide limitation to oxygen limitation. Under sulfide-limiting conditions, sulfide was virtually completely oxidized to sulfate. Under oxygen

  4. The Sulfidation of gamma-Alumina and Titania Supported (Cobalt) Molybdenum Oxide Catalysts Monitored by EXAFS.

    NARCIS (Netherlands)

    Koningsberger, D.C.; Leliveld, R.G.; Dillen, A.J. van; Geus, John W.

    1997-01-01

    The sulfidation of @c-alumina- and titania-supported(cobalt)molybdenum oxide catalysts has been studied with X-rayabsorption spectroscopy and temperature programmed sulfidation (TPS).The catalysts were stepwise sulfided at temperatures between 298 and673 K and their structure was determined with EXA

  5. Selective precipitation of heavy metals as controlled by a sulfide-selective electrode

    NARCIS (Netherlands)

    Veeken, A.H.M.; Vries, S.; Mark, van der A.

    2003-01-01

    Sulfide precipitation is superior to hydroxide precipitation for removal of heavy metals from wastewaters as it results in lower effluent concentrations and less interference from chelating agents. However, sulfide precipitation is not widely applied in practice because the dosing of sulfide cannot

  6. Sulfide-iron interactions in domestic wastewater from a gravity sewer

    NARCIS (Netherlands)

    Nielsen, A.H.; Lens, P.N.L.; Vollertsen, J.; Hvitved-Jacobsen, Th.

    2005-01-01

    Interactions between iron and sulfide in domestic wastewater from a gravity sewer were investigated with particular emphasis on redox cycling of iron and iron sulfide formation. The concentration ranges of iron and total sulfide in the experiments were 0.4-5.4 mg Fe L-1 and 0-5.1 mg S L-1, respectiv

  7. Thermochemical hydrogen production via a cycle using barium and sulfur - Reaction between barium sulfide and water

    Science.gov (United States)

    Ota, K.; Conger, W. L.

    1977-01-01

    The reaction between barium sulfide and water, a reaction found in several sulfur based thermochemical cycles, was investigated kinetically at 653-866 C. Gaseous products were hydrogen and hydrogen sulfide. The rate determining step for hydrogen formation was a surface reaction between barium sulfide and water. An expression was derived for the rate of hydrogen formation.

  8. Induction of the p75NTR by Aryl Propionic Acids in Prostate Cancer Cells

    Science.gov (United States)

    2008-12-01

    implications for prophylaxis and treatment of colon cancer. Cancer Res 1997;57:4316–24. 22. Lim JT, Piazza, GA, Han EK, et al. Sulindac derivatives... Sulindac sulfide-induced apoptosis involves death receptor 5 and the caspase 8-dependent pathway in human colon and prostate cancer cells. Cancer Res

  9. S/Se In Sulfide Inclusion In Diamond

    Science.gov (United States)

    Thomassot, E.; Couffignal, F.; Lorand, J.; Bureau, H.; Cartigny, P.; Harris, J. W.

    2009-05-01

    Sulfides are among the most common minerals found as inclusions in diamonds. Being protected from any alteration after diamond formation, they likely represent the most pristine sulfide sample of mantle rocks. Their chemical composition in major and minor elements (mainly Ni, Cu and Cr), as determined using Electron Probe Micro Analyse (EPMA), is commonly used to determine the rock type in which the diamond formed. Here we propose to apply the same technique to the trace element abundance determination. We performed selenium (Se) on sulfide inclusion in diamonds. The S/Se value could help understanding whether the diamond formed in an eclogitic or peridotitic environment and may also constrain on the magmatic differentiation of diamonds host rock as well as provide a potential surface (hydrothermal) signature in diamond inclusions. A trace element measurement scheme has been developed by EPMA at the CAMPARIS centre (Paris). Se-abundance was obtained using a 30 kV accelerating voltage and 100nA probe current. Total counting time was 800s for peak (1.1 Å ) and 400s for background on both side of peak. Analyses were duplicated by μPIXE using the LPS nuclear microprobe facility (SIS2M CEA Saclay, France). Maps from 30x30 μm2 to 70x70 μm2 were obtained by scanning a 4x4 μm2 proton beam of 3MeV, 600 pA, (0.4 to 2 μC). The two techniques show good agreement and we conclude that EPMA is well suited for accurate and precise Se measurements. We analysed five samples; two monosulfide solid solution (MSS) (Ni>22wt%) typical of the peridotitic paragenesis (P-type), and three Ni-poor sulfides (Ni<7wt%) typical of the eclogitic paragenesis (E-type). In P-type sulfides, Se-content (260 ppm) is significantly higher than previously reported in sulfides from mantle-derived lherzolites (40-160 ppm), pyroxenites (25-45 ppm) or harzburgite. The value of S/Se in MSS is low (˜1400) compared to those of the primitive mantle reservoir (3,300; McDounough et al., 1995 Chemical Geology

  10. Electrogenerative leaching of nickel sulfide concentrate with ferric chloride

    Institute of Scientific and Technical Information of China (English)

    王少芬; 方正; 王云燕; 陈阳国

    2004-01-01

    In order to utilize the chemical energy in hydrometallurgical process of sulfide minerals reasonably and to simplify the purifying process, the electrogenerative process was applied and a dual cell system was introduced to investigate FeCl3 leaching of nickel sulfide concentrate. Some factors influencing the electrogenerative leaching, such as electrode structure, temperature and solution concentration were studied. The results show that a certain quantity of electrical energy accompanied with the leached products can be acquired in the electrogenerative leaching process.The output current and power increase with the addition of acetylene black to the electrode. Varying the components of electrode just affects the polarization degree of anode. Increasing FeCl3 concentration results in a sharp increase in the output of the leaching cell when c(FeCl3) is less than 0.1 mol/L. The optimum value of NaCl concentration for electrogenerative leaching nickel sulfide concentrate with FeCl3 is 3.0 mol/L. Temperature influences electrogenerative leaching by affecting anodic and cathodic polarization simultaneously. The apparent activation energy is determined to be 34.63 kJ/mol in the range of 298 K to 322 K. The leaching rate of Ni2+ is 29.3% after FeCl3 electrogenerative leaching of nickel sulfide concentrate for 620 min with a filter bag electrode.

  11. Selective Sulfidation of Lead Smelter Slag with Sulfur

    Science.gov (United States)

    Han, Junwei; Liu, Wei; Wang, Dawei; Jiao, Fen; Qin, Wenqing

    2016-02-01

    The selective sulfidation of lead smelter slag with sulfur was studied. The effects of temperature, sulfur dosage, carbon, and Na salts additions were investigated based on thermodynamic calculation. The results indicated that more than 96 pct of zinc in the slag could be converted into sulfides. Increasing temperature, sulfur dosage, or Na salts dosage was conducive to the sulfidation of the zinc oxides in the slag. High temperature and excess Na salts would result in the more consumption of carbon and sulfur. Carbon addition not only promoted the selective sulfidation but reduced the sulfur dosage and eliminated the generation of SO2. Iron oxides had a buffering role on the sulfur efficient utilization. The transformation of sphalerite to wurtzite was feasible under reducing condition at high temperature, especially above 1273 K (1000 °C). The growth of ZnS particles largely depended upon the roasting temperature. They were significantly increased when the temperature was above 1273 K (1000 °C), which was attributed to the formation of a liquid phase.

  12. Magmatic sulfides in the porphyritic chondrules of EH enstatite chondrites

    CERN Document Server

    Piani, Laurette; Libourel, Guy; Tissandier, Laurent

    2016-01-01

    The nature and distribution of sulfides within 17 porphyritic chondrules of the Sahara 97096 EH3 enstatite chondrite have been studied by backscattered electron microscopy and electron microprobe in order to investigate the role of gas-melt interactions in the chondrule sulfide formation. Troilite (FeS) is systematically present and is the most abundant sulfide within the EH3 chondrite chondrules. It is found either poikilitically enclosed in low-Ca pyroxenes or scattered within the glassy mesostasis. Oldhamite (CaS) and niningerite [(Mg,Fe,Mn)S] are present in about 60% of the chondrules studied. While oldhamite is preferentially present in the mesostasis, niningerite associated with silica is generally observed in contact with troilite and low-Ca pyroxene. The chondrule mesostases contain high abundances of alkali and volatile elements as well as silica. Our data suggest that most of the sulfides found in EH3 chondrite chondrules are magmatic minerals that formed after the dissolution of S from a volatile-r...

  13. Hydrogen sulfide release from dairy manure storages containing gypsum bedding

    Science.gov (United States)

    Recycled gypsum products can provide a cost-effective bedding alternative for dairy producers. Manufacturers report reduced odors, moisture and bacteria in the stall environment when compared to traditional bedding. Gypsum provides a sulfate source that can be converted to hydrogen sulfide under ana...

  14. Bio-reduction of sulfide minerals to recover invisible gold

    NARCIS (Netherlands)

    Hol, A.

    2011-01-01

      Sulfide minerals, like pyrite and arsenopyrite, are of economical interest due to the presence of invisible gold locked inside these minerals. As fine grinding is often not sufficient to liberate the gold from these minerals, additional destruction techniques, based on chemical and biologica

  15. A coumarin-based colorimetric fluorescent probe for hydrogen sulfide

    Indian Academy of Sciences (India)

    Yanqiu Yang; Yu Liu; Liang Yang; Jun Liu; Kun Li; Shunzhong Luo

    2015-03-01

    A coumarin-based fluorescent probe for selective detection of hydrogen sulfide (H2S) is presented. This `off–on’ probe exhibited high selectivity towards H2S in aqueous solution with a detection limit of 30 nM. Notably, because of its dual nucleophilicity, the probe could avoid the interference of thiols and other sulfur containing compounds.

  16. Adsorption of hydrogen sulfide on montmorillonites modified with iron.

    Science.gov (United States)

    Nguyen-Thanh, Danh; Block, Karin; Bandosz, Teresa J

    2005-04-01

    Sodium-rich montmorillonite was modified with iron in order to introduce active centers for hydrogen sulfide adsorption. In the first modification, interlayer sodium cations were exchanged with iron. In another modification, iron oxocations were introduced to the clay surface. The most elaborated modification was based on doping of iron within the interlayer space of aluminum-pillared clay. The modified clay samples were tested as hydrogen sulfide adsorbents. Iron-doped samples showed a significant improvement in the capacity for H2S removal, despite of a noticeable decrease in microporosity compared to the initial pillared clay. The smallest capacity was obtained for the clay modified with iron oxocations. Variations in adsorption capacity are likely due to differences in the chemistry of iron species, degree of their dispersion on the surface, and accessibility of small pores for H2S molecule. The results suggest that on the surface of iron-modified clay hydrogen sulfide reacts with Fe(+3) forming sulfides or it is catalytically oxidized to SO2 on iron (hydro)oxides. Subsequent oxidation may lead to sulfate formation.

  17. Synthesis and photovoltaic application of coper (I) sulfide nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Yue; Wadia, Cyrus; Ma, Wanli; Sadtler, Bryce; Alivisatos, A.Paul

    2008-06-24

    We present the rational synthesis of colloidal copper(I) sulfide nanocrystals and demonstrate their application as an active light absorbing component in combination with CdS nanorods to make a solution-processed solar cell with 1.6percent power conversion efficiency on both conventional glass substrates and flexible plastic substrates with stability over a 4 month testing period.

  18. Estimation of bacterial hydrogen sulfide production in vitro

    Directory of Open Access Journals (Sweden)

    Amina Basic

    2015-06-01

    Full Text Available Oral bacterial hydrogen sulfide (H2S production was estimated comparing two different colorimetric methods in microtiter plate format. High H2S production was seen for Fusobacterium spp., Treponema denticola, and Prevotella tannerae, associated with periodontal disease. The production differed between the methods indicating that H2S production may follow different pathways.

  19. Hydrogen sulfide : role in vascular physiology and pathology

    NARCIS (Netherlands)

    Holwerda, Kim M.; Karumanchi, S. Ananth; Lely, A. Titia

    2015-01-01

    Purpose of reviewHydrogen sulfide (H2S), a colorless gas that is endogenously generated in mammals from cysteine, has important biological functions. Within the vasculature it regulates vessel tone and outgrowth of new vessels. This review summarizes recent literature on H2S signaling in the vascula

  20. 21 CFR 872.1870 - Sulfide detection device.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Sulfide detection device. 872.1870 Section 872.1870 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... periodontal pocket probing depths, detect the presence or absence of bleeding on probing, and detect...

  1. Hydrogen sulfide producing enzymes in pregnancy and preeclampsia

    NARCIS (Netherlands)

    Holwerda, K M; Bos, E M; Rajakumar, A; Ris-Stalpers, C; van Pampus, M G; Timmer, Albertus; Erwich, J J H M; Faas, M M; van Goor, H; Lely, A T

    Preeclampsia, a human pregnancy specific disorder is characterized by an anti-angiogenic state. As hydrogen sulfide (H(2)S) has pro-angiogenic and anti-oxidative characteristics, we hypothesized that H(2)S levels could play a role in the pathogenesis of preeclampsia and studied the placental

  2. Sulfide Formation And Its Impacts On A Developing Country

    DEFF Research Database (Denmark)

    Matias, Natércia; Mutuvúie, Raúl; Vollertsen, Jes;

    2014-01-01

    is expected in the near future, with the associated longer wastewater travel times and increasing problems of septicity and hydrogen sulfide gas impacts. In order to better understand the in-sewer processes under local conditions, evaluate risks and exemplify how to support general drainage systems planning...

  3. Hydrogen sulfide : physiological properties and therapeutic potential in ischaemia

    NARCIS (Netherlands)

    Bos, Eelke M.; van Goor, Harry; Joles, Jaap A.; Whiteman, Matthew; Leuvenink, Henri G. D.

    2015-01-01

    Hydrogen sulfide (H2S) has become a molecule of high interest in recent years, and it is now recognized as the third gasotransmitter in addition to nitric oxide and carbon monoxide. In this review, we discuss the recent literature on the physiology of endogenous and exogenous H2S, focusing upon the

  4. Solution processed silver sulfide thin films for filament memory applications

    Science.gov (United States)

    Yin, Shong

    Filament Memories based on resistive switching have been attracting attention in recent years as a potential replacement for flash memory in CMOS technology and as a potential candidate memory for low-cost, large-area electronics. These memories operate at low voltages with fast switching speeds. These devices are based on ionic conduction through an electrolyte layer and differ fundamentally in operation from conventional flash memory, which is based on the field effect transistor. To facilitate development of this technology, effects of film structure on ionic and electronic conducting properties and the filament formation processes must be studied. In this work, silver sulfide, a mixed ionic-electronic conductor, is used as a model material for studying the solution processing of filament memories, and to study the impact of film structure on conducting and switching properties. Three different solution processing methods are investigated for depositing silver sulfide: sulfidation of elemental silver films, and sintering of two types of silver sulfide nanoparticles. Effects of nanoparticle sintering conditions on electrolyte structured and mixed conducting properties are investigated by a combination of X-ray diffraction, electrical impedance spectroscopy and thermo-gravimetric analysis. Impact of forming voltage and time on filament morphology is examined to provide an overall view of the impact of electrical and material parameters on device operation.

  5. Luminescence in Sulfides: A Rich History and a Bright Future

    Directory of Open Access Journals (Sweden)

    Philippe F. Smet

    2010-04-01

    Full Text Available Sulfide-based luminescent materials have attracted a lot of attention for a wide range of photo-, cathodo- and electroluminescent applications. Upon doping with Ce3+ and Eu2+, the luminescence can be varied over the entire visible region by appropriately choosing the composition of the sulfide host. Main application areas are flat panel displays based on thin film electroluminescence, field emission displays and ZnS-based powder electroluminescence for backlights. For these applications, special attention is given to BaAl2S4:Eu, ZnS:Mn and ZnS:Cu. Recently, sulfide materials have regained interest due to their ability (in contrast to oxide materials to provide a broad band, Eu2+-based red emission for use as a color conversion material in white-light emitting diodes (LEDs. The potential application of rare-earth doped binary alkaline-earth sulfides, like CaS and SrS, thiogallates, thioaluminates and thiosilicates as conversion phosphors is discussed. Finally, this review concludes with the size-dependent luminescence in intrinsic colloidal quantum dots like PbS and CdS, and with the luminescence in doped nanoparticles.

  6. Potential Applications of Hydrogen Sulfide-Induced Suspended Animation

    NARCIS (Netherlands)

    H. Aslami; M.J. Schultz; N.P. Juffermans

    2009-01-01

    A suspended animation-like state has been induced in rodents with the use of hydrogen sulfide, resulting in hypothermia with a concomitant reduction in metabolic rate. Also oxygen demand was reduced, thereby protecting against hypoxia. Several therapeutic applications of induction of a hibernation-l

  7. Micelle Mediated Trace Level Sulfide Quantification through Cloud Point Extraction

    Directory of Open Access Journals (Sweden)

    Samrat Devaramani

    2012-01-01

    Full Text Available A simple cloud point extraction protocol has been proposed for the quantification of sulfide at trace level. The method is based on the reduction of iron (III to iron (II by the sulfide and the subsequent complexation of metal ion with nitroso-R salt in alkaline medium. The resulting green-colored complex was extracted through cloud point formation using cationic surfactant, that is, cetylpyridinium chloride, and the obtained surfactant phase was homogenized by ethanol before its absorbance measurement at 710 nm. The reaction variables like metal ion, ligand, surfactant concentration, and medium pH on the cloud point extraction of the metal-ligand complex have been optimized. The interference effect of the common anions and cations was studied. The proposed method has been successfully applied to quantify the trace level sulfide in the leachate samples of the landfill and water samples from bore wells and ponds. The validity of the proposed method has been studied by spiking the samples with known quantities of sulfide as well as comparing with the results obtained by the standard method.

  8. Improvements in the manufacture of sulfur from hydrogen sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Azoulay, A.

    1968-12-23

    In this process for the manufacture of sulfur from hydrogen sulfide and sulfur dioxide, the sulfur is separated from the gas after reaction by direct contact by cooling with a cooling liquid. The sulfur is carried away by the cooling liquid.

  9. EXAMINATION OF CHANGES IN AS SPECIATION IN SULFIDIC SOLUTIONS

    Science.gov (United States)

    The fate of arsenic (As) in the environment, its bioavailability and toxicity is fundamentally linked to its speciation. As in aerobic environments is predominantly arsenate (As(V)), however under reducing conditions arsenite (As(III)) species dominate. In sulfidic environments t...

  10. Thermochemical hydrogen production via a cycle using barium and sulfur: reaction between barium sulfide and water

    Energy Technology Data Exchange (ETDEWEB)

    Ota, K.; Conger, W.L.

    1977-01-01

    The reaction between barium sulfide and water, a reaction found in several sulfur based thermochemical cycles, was investigated kinetically at 653 to 866/sup 0/C. Gaseous products were hydrogen and hydrogen sulfide. The rate determining step for hydrogen formation was a surface reaction between barium sulfide and water. The rate of formation of hydrogen can be expressed as: RH2 = 1.07 x 10/sup -2/ exp (-3180/RT) (mol H/sub 2//mol BaS s). Hydrogen sulfide was produced during the initial period of reaction and the quantity of hydrogen sulfide formed during this period decreased as the temperature of reaction was increased.

  11. Volcanogenic massive sulfide occurrence model: Chapter C in Mineral deposit models for resource assessment

    Science.gov (United States)

    Shanks, W.C. Pat; Koski, Randolph A.; Mosier, Dan L.; Schulz, Klaus J.; Morgan, Lisa A.; Slack, John F.; Ridley, W. Ian; Dusel-Bacon, Cynthia; Seal, Robert R., II; Piatak, Nadine M.; Shanks, W.C. Pat; Thurston, Roland

    2012-01-01

    Volcanogenic massive sulfide deposits, also known as volcanic-hosted massive sulfide, volcanic-associated massive sulfide, or seafloor massive sulfide deposits, are important sources of copper, zinc, lead, gold, and silver (Cu, Zn, Pb, Au, and Ag). These deposits form at or near the seafloor where circulating hydrothermal fluids driven by magmatic heat are quenched through mixing with bottom waters or porewaters in near-seafloor lithologies. Massive sulfide lenses vary widely in shape and size and may be podlike or sheetlike. They are generally stratiform and may occur as multiple lenses.

  12. Lanthanide complexes as luminogenic probes to measure sulfide levels in industrial samples.

    Science.gov (United States)

    Thorson, Megan K; Ung, Phuc; Leaver, Franklin M; Corbin, Teresa S; Tuck, Kellie L; Graham, Bim; Barrios, Amy M

    2015-10-08

    A series of lanthanide-based, azide-appended complexes were investigated as hydrogen sulfide-sensitive probes. Europium complex 1 and Tb complex 3 both displayed a sulfide-dependent increase in luminescence, while Tb complex 2 displayed a decrease in luminescence upon exposure to NaHS. The utility of the complexes for monitoring sulfide levels in industrial oil and water samples was investigated. Complex 3 provided a sensitive measure of sulfide levels in petrochemical water samples (detection limit ∼ 250 nM), while complex 1 was capable of monitoring μM levels of sulfide in partially refined crude oil.

  13. Magmatic sulfides in the porphyritic chondrules of EH enstatite chondrites

    Science.gov (United States)

    Piani, Laurette; Marrocchi, Yves; Libourel, Guy; Tissandier, Laurent

    2016-12-01

    The nature and distribution of sulfides within 17 porphyritic chondrules of the Sahara 97096 EH3 enstatite chondrite have been studied by backscattered electron microscopy and electron microprobe in order to investigate the role of gas-melt interactions in the chondrule sulfide formation. Troilite (FeS) is systematically present and is the most abundant sulfide within the EH3 chondrite chondrules. It is found either poikilitically enclosed in low-Ca pyroxenes or scattered within the glassy mesostasis. Oldhamite (CaS) and niningerite [(Mg,Fe,Mn)S] are present in ≈60% of the chondrules studied. While oldhamite is preferentially present in the mesostasis, niningerite associated with silica is generally observed in contact with troilite and low-Ca pyroxene. The Sahara 97096 chondrule mesostases contain high abundances of alkali and volatile elements (average Na2O = 8.7 wt.%, K2O = 0.8 wt.%, Cl = 7100 ppm and S = 3700 ppm) as well as silica (average SiO2 = 62.8 wt.%). Our data suggest that most of the sulfides found in EH3 chondrite chondrules are magmatic minerals that formed after the dissolution of S from a volatile-rich gaseous environment into the molten chondrules. Troilite formation occurred via sulfur solubility within Fe-poor chondrule melts followed by sulfide saturation, which causes an immiscible iron sulfide liquid to separate from the silicate melt. The FeS saturation started at the same time as or prior to the crystallization of low-Ca pyroxene during the high temperature chondrule forming event(s). Protracted gas-melt interactions under high partial pressures of S and SiO led to the formation of niningerite-silica associations via destabilization of the previously formed FeS and low-Ca pyroxene. We also propose that formation of the oldhamite occurred via the sulfide saturation of Fe-poor chondrule melts at moderate S concentration due to the high degree of polymerization and the high Na-content of the chondrule melts, which allowed the activity of Ca

  14. Formation of nanocolloidal metacinnabar in mercury-DOM-sulfide systems

    Science.gov (United States)

    Gerbig, Chase A.; Kim, Christopher S.; Stegemeier, John P.; Ryan, Joseph N.; Aiken, George R.

    2011-01-01

    Direct determination of mercury (Hg) speciation in sulfide-containing environments is confounded by low mercury concentrations and poor analytical sensitivity. Here we report the results of experiments designed to assess mercury speciation at environmentally relevant ratios of mercury to dissolved organic matter (DOM) (i.e., -1) by combining solid phase extraction using C18 resin with extended X-ray absorption fine structure (EXAFS) spectroscopy. Aqueous Hg(II) and a DOM isolate were equilibrated in the presence and absence of 100 μM total sulfide. In the absence of sulfide, mercury adsorption to the resin increased as the Hg:DOM ratio decreased and as the strength of Hg-DOM binding increased. EXAFS analysis indicated that in the absence of sulfide, mercury bonds with an average of 2.4 ± 0.2 sulfur atoms with a bond length typical of mercury-organic thiol ligands (2.35 Å). In the presence of sulfide, mercury showed greater affinity for the C18 resin, and its chromatographic behavior was independent of Hg:DOM ratio. EXAFS analysis showed mercury–sulfur bonds with a longer interatomic distance (2.51–2.53 Å) similar to the mercury–sulfur bond distance in metacinnabar (2.53 Å) regardless of the Hg:DOM ratio. For all samples containing sulfide, the sulfur coordination number was below the ideal four-coordinate structure of metacinnabar. At a low Hg:DOM ratio where strong binding DOM sites may control mercury speciation (1.9 nmol mg-1) mercury was coordinated by 2.3 ± 0.2 sulfur atoms, and the coordination number rose with increasing Hg:DOM ratio. The less-than-ideal coordination numbers indicate metacinnabar-like species on the nanometer scale, and the positive correlation between Hg:DOM ratio and sulfur coordination number suggests progressively increasing particle size or crystalline order with increasing abundance of mercury with respect to DOM. In DOM-containing sulfidic systems nanocolloidal metacinnabar-like species may form, and these species need to

  15. Nanomaterials made of non-toxic metallic sulfides: A systematic review of their potential biomedical applications.

    Science.gov (United States)

    Argueta-Figueroa, Liliana; Martínez-Alvarez, O; Santos-Cruz, J; Garcia-Contreras, R; Acosta-Torres, L S; de la Fuente-Hernández, J; Arenas-Arrocena, M C

    2017-07-01

    Metallic sulfides involve the chemical bonding of one or more sulfur atoms to a metal. Metallic sulfides are cheap, abundant semiconductor materials that can be used for several applications. However, an important and emerging use for non-toxic metallic sulfides in biomedical applications has arisen quickly in the medical field. In this systematic review, the available data from electronic databases were collected according to PRISMA alignments for systematic reviews. This review shows that these metallic sulfides could be promising for biomedical uses and applications. This systematic review is focused primarily on the following compounds: silver sulfide, copper sulfide, and iron sulfide. The aim of this review was to provide a quick reference on synthesis methods, biocompatibility, recent advances and perspectives, with remarks on future improvements. The toxicity of metallic sulfides depends directly on the cytotoxicity of their interactions with cells and tissues. Metallic sulfides have potential biomedical applications due to their antibacterial properties, uses in imaging and diagnostics, therapies such as photothermal therapy and chemotherapy in tumors and cancer cells, drug delivery and the fabrication of biosensors for the sensitive and selective detection of moieties, among others. Although current evidence about metallic sulfide NPs is promising, there are still several issues to be addressed before these NPs can be used in biomedicine. The current review is a brief but significant guide to metallic sulfides and their potential uses in the biomedical field. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Hydrogen sulfide waste treatment by microwave plasma-chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Harkness, J.B.L.; Doctor, R.D.

    1994-03-01

    A waste-treatment process that recovers both hydrogen and sulfur from industrial acid-gas waste streams is being developed to replace the Claus technology, which recovers only sulfur. The proposed process is derived from research reported in the Soviet technical literature and uses microwave (or radio-frequency) energy to initiate plasma-chemical reactions that dissociate hydrogen sulfide into elemental hydrogen and sulfur. This process has several advantages over the current Claus-plus-tail-gas-cleanup technology, which burns the hydrogen to water. The primary advantage of the proposal process is its potential for recovering and recycling hydrogen more cheaply than the direct production of hydrogen. Since unconverted hydrogen sulfide is recycled to the plasma reactor, the plasma-chemical process has the potential for sulfur recoveries in excess of 99% without the additional complexity of the tail-gas-cleanup processes associated with the Claus technology. There may also be some environmental advantages to the plasma-chemical process, because the process purge stream would primarily be the carbon dioxide and water contained in the acid-gas waste stream. Laboratory experiments with pure hydrogen sulfide have demonstrated the ability of the process to operate at or above atmospheric pressure with an acceptable hydrogen sulfide dissociation energy. Experiments with a wide range of acid-gas compositions have demonstrated that carbon dioxide and water are compatible with the plasma-chemical dissociation process and that they do not appear to create new waste-treatment problems. However, carbon dioxide does have negative impacts on the overall process. First, it decreases the hydrogen production, and second, it increases the hydrogen sulfide dissociation energy.

  17. Direct rapid determination of traces of sulfide in environment samples

    Institute of Scientific and Technical Information of China (English)

    郭方遒; 黄兰芳; 梁逸曾

    2002-01-01

    An improved ethylene blue method for determination of sulfide is developed. It has been adapted to a direct determination of sulfide by both common spectrophotometric method and total differential spectrophotometric method. In common spectrophotometric method, the calibration curve is A=1.69ρ+0.006 and the correlation coefficient is 0.9994.The apparent molar absorptivity is 5.42×104 L*mol-1*cm-1 and calibration curve is liner when ρ is in the range of 0-0.9 mg*L-1. In total differential spectrophotometric method, the calibration curve is A=9.25ρ+0.004 and the correlation coefficient is 0.9996. The apparent molar absorptivity is 2.96×105 L*mol-1*cm-1and calibration curve is liner when ρ is in the range of 0-0.10 mg*L-1. The sensitivity of this method is increased significantly compared with the former ethylene blue method. The speed of reaction is also faster than the former one. The limit of detection is found to be 1.0 ng*mL-1 by both common spectrophotometric method and total differential spectrophotometric method. Ten replicate analyses of a sample solution containing 100 ng*mL-1sulfide give a relative standard deviation of 1.8%. The effects of various cations and anions on the determination of sulfide are studied and procedures for removal of interference is described. The method is used for the determination of sulfide in environment samples with satisfactory results.

  18. Biogeographic Congruency among Bacterial Communities from Terrestrial Sulfidic Springs

    Directory of Open Access Journals (Sweden)

    Brendan eHeadd

    2014-09-01

    Full Text Available Terrestrial sulfidic springs support diverse microbial communities by serving as stable conduits for geochemically diverse and nutrient-rich subsurface waters. Microorganisms that colonize terrestrial springs likely originate from groundwater, but may also be sourced from the surface. As such, the biogeographic distribution of microbial communities inhabiting sulfidic springs should be controlled by a combination of spring geochemistry and surface and subsurface transport mechanisms, and not necessarily geographic proximity to other springs. We examined the bacterial diversity of seven springs to test the hypothesis that occurrence of taxonomically similar microbes, important to the sulfur cycle, at each spring is controlled by geochemistry. Complementary Sanger sequencing and 454 pyrosequencing of 16S rRNA genes retrieved five proteobacterial classes, and Bacteroidetes, Chlorobi, Chloroflexi, and Firmicutes phyla from all springs, which suggested the potential for a core sulfidic spring microbiome. Among the putative sulfide-oxidizing groups (Epsilonproteobacteria and Gammaproteobacteria, up to 83% of the sequences from geochemically similar springs clustered together. Abundant populations of Hydrogenimonas-like or Sulfurovum-like spp. (Epsilonproteobacteria occurred with abundant Thiothrix and Thiofaba spp. (Gammaproteobacteria, but Arcobacter-like and Sulfurimonas spp. (Epsilonproteobacteria occurred with less abundant gammaproteobacterial populations. These distribution patterns confirmed that geochemistry rather than biogeography regulates bacterial dominance at each spring. Potential biogeographic controls were related to paleogeologic sedimentation patterns that could control long-term microbial transport mechanisms that link surface and subsurface environments. Knowing the composition of a core sulfidic spring microbial community could provide a way to monitor diversity changes if a system is threatened by anthropogenic processes or

  19. Blood Components Prevent Sulfide Poisoning of Respiration of the Hydrothermal Vent Tube Worm Riftia pachyptila

    Science.gov (United States)

    Powell, Mar A.; Somero, George N.

    1983-01-01

    Respiration of plume tissue of the hydrothermal vent tube worm Riftia pachyptila is insensitive to sulfide poisoning in contrast to tissues of animals that do not inhabit vents. Permeability barriers may not be responsible for this insensitivity since plume homogenates are also resistant to sulfide poisoning. Cytochrome c oxidase of plume, however, is strongly inhibited by sulfide at concentrations less than 10 μ M. Factors present in blood, but not in cytosol, prevent sulfide from inhibiting cytochrome c oxidase. Avoidance of sulfide poisoning of respiration in Riftia pachyptila thus appears to involve a blood-borne factor having a higher sulfide affinity than that of cytochrome c oxidase, with the result that appreciable amounts of free sulfide are prevented from accumulating in the blood and entering the intracellular compartment.

  20. Sulfide and ammonium oxidation, acetate mineralization by denitrification in a multipurpose UASB reactor.

    Science.gov (United States)

    Beristain-Cardoso, Ricardo; Gómez, Jorge; Méndez-Pampín, Ramón

    2011-02-01

    The physiological and kinetic behavior of a denitrifying granular sludge exposed to different sulfide loading rates (55-295 mg/L d) were evaluated in a UASB reactor fed with acetate, ammonium and nitrate. At any sulfide loading rates, the consumption efficiencies of sulfide, acetate and ammonium were above 95%, while nitrate consumption efficiencies were around 62-72%. At the highest sulfide loading rate the ammonium was used as electron donor for N(2) production. The increase of sulfide loading rate also affected the fate of sulfide oxidation, since elemental sulfur was the main end product instead of sulfate. However, the lithotrophic denitrifying kinetic was not affected. FISH oligonucleotide probes for Thiobacillus denitrificans, Thiomiscropira denitrificans, genus Paracoccus and Pseudomonas spp. were used to follow the microbial ecology. The results of this work have shown that four pollutants could simultaneously be removed, namely, sulfide, ammonium, acetate and nitrate under well defined denitrifying conditions. Copyright © 2010 Elsevier Ltd. All rights reserved.

  1. Hydrogen sulfide and resolution of acute inflammation: A comparative study utilizing a novel fluorescent probe.

    Science.gov (United States)

    Dufton, Neil; Natividad, Jane; Verdu, Elena F; Wallace, John L

    2012-01-01

    Hydrogen sulfide is an essential gasotransmitter associated with numerous pathologies. We assert that hydrogen sulfide plays an important role in regulating macrophage function in response to subsequent inflammatory stimuli, promoting clearance of leukocyte infiltrate and reducing TNF-α levels in vivo following zymosan-challenge. We describe two distinct methods of measuring leukocyte hydrogen sulfide synthesis; methylene blue formation following zinc acetate capture and a novel fluorescent sulfidefluor probe. Comparison of these methods, using pharmacological tools, revealed they were complimentary in vitro and in vivo. We demonstrate the application of sulfidefluor probe to spectrofluorimetry, flow cytometry and whole animal imaging, to monitor the regulation of hydrogen sulfide synthesis in vivo during dynamic inflammatory processes. Both methodologies revealed that granulocyte infiltration negatively affects hydrogen sulfide synthesis. Our report offers an insight into the profile of hydrogen sulfide synthesis during inflammation and highlight opportunities raised by the development of novel fluorescent hydrogen sulfide probes.

  2. Simulation of sulfide buildup in wastewater and atmosphere of sewer networks.

    Science.gov (United States)

    Nielsen, A H; Yongsiri, C; Hvitved-Jacobsen, T; Vollertsen, J

    2005-01-01

    A model concept for prediction of sulfide buildup in sewer networks is presented. The model concept is an extension to--and a further development of--the WATS model (Wastewater Aerobic-anaerobic Transformations in Sewers), which has been developed by Hvitved-Jacobsen and co-workers at Aalborg University. In addition to the sulfur cycle, the WATS model simulates changes in dissolved oxygen and carbon fractions of different biodegradability. The sulfur cycle was introduced via six processes: 1. sulfide production taking place in the biofilm covering the permanently wetted sewer walls; 2. biological sulfide oxidation in the permanently wetted biofilm; 3. chemical and biological sulfide oxidation in the water phase; 4. sulfide precipitation with metals present in the wastewater; 5. emission of hydrogen sulfide to the sewer atmosphere and 6. adsorption and oxidation of hydrogen sulfide on the moist sewer walls where concrete corrosion may take place.

  3. Galvanic coupling and its effect on origin potential flotation system of sulfide minerals

    Institute of Scientific and Technical Information of China (English)

    顾帼华; 戴晶平; 王晖; 邱冠周

    2004-01-01

    The galvanic coupling formed in origin potential flotation systems of sulfide minerals can be divided into three types: sulfide mineral-sulfide mineral-water system; sulfide mineral-steel ball-water system; and sulfide mineral-sulfide mineral-collector system. In this paper, taking lead, zinc, iron sulfide mineral systems for examples,several models of galvanic coupling were proposed and the effects of galvanic coupling on flotation were discussed. A galvanic contact between galena (or sphalerite) and pyrite contributes to decreasing the content of zinc in lead concentrate, and enhances remarkably the absorption of collector on the galena surface. During grinding, due to galvanic interactions between minerals and steel medium, Fe(OH)3 formed covers on the cathodic mineral surface, affecting its floatability.

  4. Pyrite formation and mineral transformation pathways upon sulfidation of ferric hydroxides depend on mineral type and sulfide concentration

    NARCIS (Netherlands)

    Peiffer, Stefan; Behrends, Thilo; Hellige, Katrin; Larese-Casanova, Philip; Wan, Moli; Pollok, Kilian

    2015-01-01

    The reaction of ferric (hydr)oxides with dissolved sulfide does not lead to the instantaneous production of thermodynamically stable products but can induce a variety of mineral transformations including the formation of metastable intermediates. The importance of the various transformation pathways

  5. Electrochemical Behavior of Sulfide at the Silver Rotating Disc Electrode. I. Polarization Behavior of Silver Sulfide Films.

    Science.gov (United States)

    1981-05-01

    from Reporf) C IS. SUPPLEMENTARY NOTES Prepared for publication in The Journal of Electroanalytical Chemistry 19. KEY WORDS (Continue on reverse aide it...SULFIDE FILMS by KUNIO SHIMIZU, KOICH AOKI AND ROBERT A. OSFERYOUNG Accepted for Publication in The Journal of Electroanalytical Chemistry Department

  6. The mechanism of the catalytic oxidation of hydrogen sulfide: II. Kinetics and mechanism of hydrogen sulfide oxidation catalyzed by sulfur

    NARCIS (Netherlands)

    Steijns, M.; Derks, F.; Verloop, A.; Mars, P.

    1976-01-01

    The kinetics of the catalytic oxidation of hydrogen sulfide by molecular oxygen have been studied in the temperature range 20–250 °C. The primary reaction product is sulfur which may undergo further oxidation to SO2 at temperatures above 200 °C. From the kinetics of this autocatalytic reaction we

  7. Pyrite formation and mineral transformation pathways upon sulfidation of ferric hydroxides depend on mineral type and sulfide concentration

    NARCIS (Netherlands)

    Peiffer, Stefan; Behrends, Thilo; Hellige, Katrin; Larese-Casanova, Philip; Wan, Moli; Pollok, Kilian

    2015-01-01

    The reaction of ferric (hydr)oxides with dissolved sulfide does not lead to the instantaneous production of thermodynamically stable products but can induce a variety of mineral transformations including the formation of metastable intermediates. The importance of the various transformation pathways

  8. Properties of iron sulfide, hydrosulfide, and mixed sulfide/hydrosulfide cluster anions through photoelectron spectroscopy and density functional theory calculations

    Science.gov (United States)

    Yin, Shi; Bernstein, Elliot R.

    2016-10-01

    A new magnetic-bottle time-of-flight photoelectron spectroscopy (PES) apparatus is constructed in our laboratory. The PES spectra of iron sulfide, hydrosulfide, and mixed sulfide/hydrosulfide [FeSm(SH)n-; m, n = 0-3, 0 theory. The most probable structures and ground state spin multiplicity for these cluster anions are tentatively assigned by comparing their theoretical first vertical detachment energies (VDEs) with their respective experiment values. The behavior of S and (SH) as ligands in these iron sulfide, hydrosulfide, and mixed sulfide/hydrosulfide cluster anions is investigated and compared. The experimental first VDEs for Fe(SH)1-3- cluster anions are lower than those found for their respective FeS1-3- cluster anions. The experimental first VDEs for FeS1-3- clusters are observed to increase for the first two S atoms bound to Fe-; however, due to the formation of an S-S bond for the FeS3- cluster, its first VDE is found to be ˜0.41 eV lower than the first VDE for the FeS2- cluster. The first VDEs of Fe(SH)1-3- cluster anions are observed to increase with the increasing numbers of SH groups. The calculated partial charges of the Fe atom for ground state FeS1-3- and Fe(SH)1-3- clusters are apparently related to and correlated with their determined first VDEs. The higher first VDE is correlated with a higher, more positive partial charge for the Fe atom of these cluster anions. Iron sulfide/hydrosulfide mixed cluster anions are also explored in this work: the first VDE for FeS(SH)- is lower than that for FeS2-, but higher than that for Fe(SH)2-; the first VDEs for FeS2(SH)- and FeS(SH)2- are close to that for FeS3-, but higher than that for Fe(SH)3-. The first VDEs of general iron sulfide, hydrosulfide, and mixed sulfide/hydrosulfide clusters [FeSm(SH)n-; m, n = 0-3, 0 < (m + n) ≤ 3] are dependent on three properties of these anions: 1. the partial charge on the Fe atom, 2. disulfide bond formation (S-S) in the cluster, and 3. the number of hydrosulfide

  9. Properties of iron sulfide, hydrosulfide, and mixed sulfide/hydrosulfide cluster anions through photoelectron spectroscopy and density functional theory calculations.

    Science.gov (United States)

    Yin, Shi; Bernstein, Elliot R

    2016-10-21

    A new magnetic-bottle time-of-flight photoelectron spectroscopy (PES) apparatus is constructed in our laboratory. The PES spectra of iron sulfide, hydrosulfide, and mixed sulfide/hydrosulfide [FeSm(SH)n(-); m, n = 0-3, 0 density functional theory. The most probable structures and ground state spin multiplicity for these cluster anions are tentatively assigned by comparing their theoretical first vertical detachment energies (VDEs) with their respective experiment values. The behavior of S and (SH) as ligands in these iron sulfide, hydrosulfide, and mixed sulfide/hydrosulfide cluster anions is investigated and compared. The experimental first VDEs for Fe(SH)1-3(-) cluster anions are lower than those found for their respective FeS1-3(-) cluster anions. The experimental first VDEs for FeS1-3(-) clusters are observed to increase for the first two S atoms bound to Fe(-); however, due to the formation of an S-S bond for the FeS3(-) cluster, its first VDE is found to be ∼0.41 eV lower than the first VDE for the FeS2(-) cluster. The first VDEs of Fe(SH)1-3(-) cluster anions are observed to increase with the increasing numbers of SH groups. The calculated partial charges of the Fe atom for ground state FeS1-3(-) and Fe(SH)1-3(-) clusters are apparently related to and correlated with their determined first VDEs. The higher first VDE is correlated with a higher, more positive partial charge for the Fe atom of these cluster anions. Iron sulfide/hydrosulfide mixed cluster anions are also explored in this work: the first VDE for FeS(SH)(-) is lower than that for FeS2(-), but higher than that for Fe(SH)2(-); the first VDEs for FeS2(SH)(-) and FeS(SH)2(-) are close to that for FeS3(-), but higher than that for Fe(SH)3(-). The first VDEs of general iron sulfide, hydrosulfide, and mixed sulfide/hydrosulfide clusters [FeSm(SH)n(-); m, n = 0-3, 0 number of hydrosulfide ligands in the cluster. The higher the partial charge on the Fe atom of these clusters, the larger the first VDE

  10. Extreme enrichment of Se, Te, PGE and Au in Cu sulfide microdroplets: evidence from LA-ICP-MS analysis of sulfides in the Skaergaard Intrusion, east Greenland

    Science.gov (United States)

    Holwell, David A.; Keays, Reid R.; McDonald, Iain; Williams, Megan R.

    2015-12-01

    The Platinova Reef, in the Skaergaard Intrusion, east Greenland, is an example of a magmatic Cu-PGE-Au sulfide deposit formed in the latter stages of magmatic differentiation. As is characteristic with such deposits, it contains a low volume of sulfide, displays peak metal offsets and is Cu rich but Ni poor. However, even for such deposits, the Platinova Reef contains extremely low volumes of sulfide and the highest Pd and Au tenor sulfides of any magmatic ore deposit. Here, we present the first LA-ICP-MS analyses of sulfide microdroplets from the Platinova Reef, which show that they have the highest Se concentrations (up to 1200 ppm) and lowest S/Se ratios (190-700) of any known magmatic sulfide deposit and have significant Te enrichment. In addition, where sulfide volume increases, there is a change from high Pd-tenor microdroplets trapped in situ to larger, low tenor sulfides. The transition between these two sulfide regimes is marked by sharp peaks in Au, and then Te concentration, followed by a wider peak in Se, which gradually decreases with height. Mineralogical evidence implies that there is no significant post-magmatic hydrothermal S loss and that the metal profiles are essentially a function of magmatic processes. We propose that to generate these extreme precious and semimetal contents, the sulfides must have formed from an anomalously metal-rich package of magma, possibly formed via the dissolution of a previously PGE-enriched sulfide. Other processes such as kinetic diffusion may have also occurred alongside this to produce the ultra-high tenors. The characteristic metal offset pattern observed is largely controlled by partitioning effects, producing offset peaks in the order Pt+Pd>Au>Te>Se>Cu that are entirely consistent with published D values. This study confirms that extreme enrichment in sulfide droplets can occur in closed-system layered intrusions in situ, but this will characteristically form ore deposits that are so low in sulfide that they do

  11. Kinetic studies of sulfide mineral oxidation and xanthate adsorption

    Science.gov (United States)

    Mendiratta, Neeraj K.

    2000-10-01

    Sulfide minerals are a major source of metals; however, certain sulfide minerals, such as pyrite and pyrrhotite, are less desirable. Froth flotation is a commonly used separation technique, which requires the use of several reagents to float and depress different sulfide minerals. Xanthate, a thiol collector, has gained immense usage in sulfide minerals flotation. However, some sulfides are naturally hydrophobic and may float without a collector. Iron sulfides, such as pyrite and pyrrhotite, are few of the most abundant minerals, yet economically insignificant. Their existence with other sulfide minerals leads to an inefficient separation process as well as environmental problems, such as acid mine drainage during mining and processing and SO 2 emissions during smelting process. A part of the present study is focused on understanding their behavior, which leads to undesired flotation and difficulties in separation. The major reasons for the undesired flotation are attributed to the collectorless hydrophobicity and the activation with heavy metal ions. To better understand the collectorless hydrophobicity of pyrite, Electrochemical Impedance Spectroscopy (EIS) of freshly fractured pyrite electrodes was used to study the oxidation and reduction of the mineral. The EIS results showed that the rate of reaction increases with oxidation and reduction. At moderate oxidizing potentials, the rate of reaction is too slow to replenish hydrophilic iron species leaving hydrophobic sulfur species on the surface. However, at higher potentials, iron species are replaced fast enough to depress its flotation. Effects of pH and polishing were also explored using EIS. Besides collectorless hydrophobicity, the activation of pyrrhotite with nickel ions and interaction with xanthate ions makes the separation more difficult. DETA and SO2 are commonly used as pyrrhotite depressants; however, the mechanism is not very well understood. Contact angle measurements, cyclic voltammetry and Tafel

  12. Trace elements in sulfide inclusions from Yakutian diamonds

    Science.gov (United States)

    Bulanova, G. P.; Griffin, W. L.; Ryan, C. G.; Shestakova, O. Y.; Barnes, S.-J.

    1996-07-01

    Sulfide inclusions in diamonds may provide the only pristine samples of mantle sulfides, and they carry important information on the distribution and abundances of chalcophile elements in the deep lithosphere. Trace-element abundances were measured by proton microprobe in >50 sulfide inclusions (SDI) from Yakutian diamonds; about half of these were measured in situ in polished plates of diamonds, providing information on the spatial distribution of compositional variations. Many of the diamonds were identified as peridotitic or eclogitic from the nature of coexisting silicate or oxide inclusions. Known peridotitic diamonds contain SDIs with Ni contents of 22 36%, consistent with equilibration between olivine, monosulfide solid solution (MSS) and sulfide melt, whereas SDIs in eclogitic diamonds contain 0 12% Ni. A group of diamonds without silicate or oxide inclusions has SDIs with 11 18% Ni, and may be derived from pyroxenitic parageneses. Eclogitic SDIs have lower Ni, Cu and Te than peridotitic SDIs; the ranges of the two parageneses overlap for Se, As and Mo. The Mo and Se contents range up to 700 and 300 ppm, respectively; the highest levels are found in peridotitic diamonds. Among the in-situ SDIs, significant Zn and Pb levels are found in those connected by cracks to diamond surfaces, and these elements reflect interaction with kimberlitic melt. Significant levels of Ru (30 1300 ppm) and Rh (10 170 ppm) are found in many peridotitic SDIs; SDIs in one diamond with wustite and olivine inclusions and complex internal structures have high levels of other platinum-group elements (PGEs) as well, and high chondrite-normalized Ir/Pd. Comparison with experimental data on element partitioning between crystals of monosulfide solid solution (MSS) and sulfide melts suggests that most of the inclusions in both parageneses were trapped as MSS, while some high-Cu SDIs with high Pd±Rh may represent fractionated sulfide melts. Spatial variations of SDI composition within

  13. Influence of sulfide concentration on the corrosion behavior of titanium in a simulated oral environment.

    Science.gov (United States)

    Harada, Rino; Takemoto, Shinji; Kinoshita, Hideaki; Yoshinari, Masao; Kawada, Eiji

    2016-05-01

    This study assessed the corrosion behavior of titanium in response to sulfide by determining the effects of sulfide concentration and pH over immersion period. Corrosion was evaluated through changes in color, glossiness, surface characterization, and titanium release. Sulfide solutions were prepared in 3 different concentrations with Na2S, each in pH unadjusted (sulfide-alkaline) and pH adjusted to 7.5 (sulfide-neutral). Titanium discoloration increased and glossiness decreased as sulfide concentration and immersion period increased in sulfide-alkaline solutions. Coral-like complexes were observed on the surface of these specimens, which became more pronounced as concentration increased. Small amounts of titanium release were detected in sulfide-alkaline solutions; however, this was not affected by immersion periods. Corrosion was indicated through considerable surface oxidation suggesting the formation of a thick oxide layer. No significant changes in color and glossiness, or titanium release were indicated for titanium specimens immersed in sulfide-neutral solutions indicating that pH had a significant effect on corrosion. Our findings suggest that a thick oxide layer on the titanium surface was formed in sulfide-alkaline solutions due to excessive oxidation.

  14. Hydrogen sulfide inhalation ameliorates allergen induced airway hypereactivity by modulating mast cell activation.

    Science.gov (United States)

    Roviezzo, Fiorentina; Bertolino, Antonio; Sorrentino, Rosalinda; Terlizzi, Michela; Matteis, Maria; Calderone, Vincenzo; Mattera, Valentina; Martelli, Alma; Spaziano, Giuseppe; Pinto, Aldo; D'Agostino, Bruno; Cirino, Giuseppe

    2015-10-01

    Compelling evidence suggests that hydrogen sulfide represents an important gaseous transmitter in the mammalian respiratory system. In the present study, we have evaluated the role of mast cells in hydrogen sulfide-induced effects on airways in a mouse model of asthma. Mice were sensitized to ovalbumin and received aerosol of a hydrogen sulfide donor (NaHS; 100 ppm) starting at day 7 after ovalbumin challenge. Exposure to hydrogen sulfide abrogated ovalbumin-induced bronchial hypereactivity as well as the increase in lung resistance. Concomitantly, hydrogen sulfide prevented mast cell activity as well as FGF-2 and IL-13 upregulation. Conversely, pulmonary inflammation and the increase in plasmatic IgE levels were not affected by hydrogen sulfide. A lack of hydrogen sulfide effects in mast cell deficient mice occurred. Primary fibroblasts harvested from ovalbumin-sensitized mice showed an increased proliferation rate that was inhibited by hydrogen sulfide aerosol. Furthermore, ovalbumin-induced transdifferentiation of pulmonary fibroblasts into myofibroblasts was reversed. Finally, hydrogen sulfide did abrogate in vitro the degranulation of the mast cell-like RBL-2H3 cell line. Similarly to the in vivo experiments the inhibitory effect was present only when the cells were activated by antigen exposure. In conclusion, inhaled hydrogen sulfide improves lung function and inhibits bronchial hyper-reactivity by modulating mast cells and in turn fibroblast activation.

  15. Influence of pipe material and surfaces on sulfide related odor and corrosion in sewers.

    Science.gov (United States)

    Nielsen, Asbjørn Haaning; Vollertsen, Jes; Jensen, Henriette Stokbro; Wium-Andersen, Tove; Hvitved-Jacobsen, Thorkild

    2008-09-01

    Hydrogen sulfide oxidation on sewer pipe surfaces was investigated in a pilot scale experimental setup. The experiments were aimed at replicating conditions in a gravity sewer located immediately downstream of a force main where sulfide related concrete corrosion and odor is often observed. During the experiments, hydrogen sulfide gas was injected intermittently into the headspace of partially filled concrete and plastic (PVC and HDPE) sewer pipes in concentrations of approximately 1,000 ppm(v). Between each injection, the hydrogen sulfide concentration was monitored while it decreased because of adsorption and subsequent oxidation on the pipe surfaces. The experiments showed that the rate of hydrogen sulfide oxidation was approximately two orders of magnitude faster on the concrete pipe surfaces than on the plastic pipe surfaces. Removal of the layer of reaction (corrosion) products from the concrete pipes was found to reduce the rate of hydrogen sulfide oxidation significantly. However, the rate of sulfide oxidation was restored to its background level within 10-20 days. A similar treatment had no observable effect on hydrogen sulfide removal in the plastic pipe reactors. The experimental results were used to model hydrogen sulfide oxidation under field conditions. This showed that the gas-phase hydrogen sulfide concentration in concrete sewers would typically amount to a few percent of the equilibrium concentration calculated from Henry's law. In the plastic pipe sewers, significantly higher concentrations were predicted because of the slower adsorption and oxidation kinetics on such surfaces.

  16. The removal of hydrogen sulfide from gas streams using an aqueous metal sulfate absorbent. Part 2. The regeneration of copper sulfide to copper oxide - An experimental study

    NARCIS (Netherlands)

    ter Maat, Hendrik; ter Maat, H.; Hogendoorn, Kees; Versteeg, Geert

    2005-01-01

    Aim of this study was to investigate the possibilities for a selective and efficient method to convert copper(II) sulfide (CuS) into copper(II) oxide (CuO). The oxidation of copper sulfide has been studied experimentally using a thermogravimetric analyzer (TGA) at temperatures ranging from 450 to

  17. The removal of hydrogen sulfide from gas streams using an aqueous metal sulfate absorbent : Part II. the regeneration of copper sulfide to copper oxide - An experimental study

    NARCIS (Netherlands)

    Ter Maat, H.; Hogendoorn, J. A.; Versteeg, G. F.

    2005-01-01

    Aim of this study was to investigate the possibilities for a selective and efficient method to convert copper(II) sulfide (CuS) into copper(II) oxide (CuO). The oxidation of copper sulfide has been studied experimentally using a thermogravimetric analyzer (TGA) at temperatures ranging from 450 to 75

  18. The removal of hydrogen sulfide from gas streams using an aqueous metal sulfate absorbent: Part II. The regeneration of copper sulfide to copper oxide—an experimental study

    NARCIS (Netherlands)

    Maat, ter H.; Hogendoorn, J.A.; Versteeg, G.F.

    2005-01-01

    Aim of this study was to investigate the possibilities for a selective and efficient method to convert copper(II) sulfide (CuS) into copper(II) oxide (CuO). The oxidation of copper sulfide has been studied experimentally using a thermogravimetric analyzer (TGA) at temperatures ranging from 450 to 75

  19. The removal of hydrogen sulfide from gas streams using an aqueous metal sulfate absorbent : Part II. the regeneration of copper sulfide to copper oxide - An experimental study

    NARCIS (Netherlands)

    Ter Maat, H.; Hogendoorn, J. A.; Versteeg, G. F.

    2005-01-01

    Aim of this study was to investigate the possibilities for a selective and efficient method to convert copper(II) sulfide (CuS) into copper(II) oxide (CuO). The oxidation of copper sulfide has been studied experimentally using a thermogravimetric analyzer (TGA) at temperatures ranging from 450 to

  20. Crustal contamination and sulfide immiscibility history of the Permian Huangshannan magmatic Ni-Cu sulfide deposit, East Tianshan, NW China

    Science.gov (United States)

    Mao, Ya-Jing; Qin, Ke-Zhang; Tang, Dong-Mei; Feng, Hong-Ye; Xue, Sheng-Chao

    2016-11-01

    The Huangshannan mafic-ultramafic intrusion is a Permian Ni-Cu sulfide-bearing intrusion in the southern margin of the Central Asian Orogenic Belt. The intrusion consists of an ultramafic unit, which is composed of lherzolite and olivine websterite, and a mafic unit, which is composed of olivine gabbronorite, gabbronorite and leuco-gabbronorite. This intrusion was formed by two separate pulses of magma: a more primitive magma for the early ultramafic unit and a more evolved magma for the late mafic unit. U-Pb isotope geochronology of zircon from the mafic unit yields an age of 278 ± 2 Ma. According to its olivine and Cr-rich spinel compositions, the estimated parental magma of lherzolite for the Huangshannan intrusion has 12.4 wt.% MgO, indicating picritic affinity. Fractional crystallization modeling results and the presence of rounded sulfide inclusions in an olivine crystal (Fo 86.7) indicate that sulfide immiscibility was achieved at the beginning of olivine fractionation. Co-magmatic zircon crystals from gabbronorite have a δ18O value close to 6.5‰, which is 1.2‰ higher than the typical mantle value and suggests significant crustal contamination (∼20%). The positive εHf(t) values of co-magmatic zircon (which vary from +9.2 to +15.3) and positive whole rock εNd(t) values (which vary from +4.7 to +7.8) also indicate that the parental magma was derived from a depleted mantle source and contaminated by 5-20% juvenile arc crust and then by ∼5% upper crustal materials. However, modeling results of sulfur content at sulfide saturation reveal that such a large amount of crustal contamination is not sufficient to trigger sulfide saturation in the parental magma, which strongly suggests that external sulfur addition, probably during contamination, has played a critical role in causing sulfide immiscibility. Furthermore, the arc magmatism geochemical signatures of the Huangshannan intrusion, such as significant Nb and Ta depletion relative to La and low Ca

  1. Fabrication and applications of copper sulfide (CuS) nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Shamraiz, Umair, E-mail: umairshamraiz@gmail.com; Hussain, Raja Azadar, E-mail: hussainazadar@gamil.com; Badshah, Amin, E-mail: aminbadshah@yahoo.com

    2016-06-15

    This review article presents different fabrication procedures (under the headlines of solvothermal routes, aerosol methods, solution methods and thermolysis), and applications (photocatalytic degradation, ablation of cancer cells, electrode material in lithium ion batteries and in gas sensing, organic solar cells, field emission properties, super capacitor applications, photoelectrochemical performance of QDSCs, photocatalytic reduction of organic pollutants, electrochemical bio sensing, enhanced PEC characteristics of pre-annealed CuS film electrodes) of copper sulfide (Covellite). - Highlights: • This review article presents the synthesis and applications of copper sulfide. • CuS has been used over the years for different applications in nanoscience. • Different synthetic protocols are followed for their preparation which help in the possible modifications in the morphology of CuS.

  2. Oxygen-free atomic layer deposition of indium sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Martinson, Alex B.; Hock, Adam S.; McCarthy, Robert; Weimer, Matthew S.

    2016-07-05

    A method for synthesizing an In(III) N,N'-diisopropylacetamidinate precursor including cooling a mixture comprised of diisopropylcarbodiimide and diethyl ether to approximately -30.degree. C., adding methyllithium drop-wise into the mixture, allowing the mixture to warm to room temperature, adding indium(III) chloride as a solid to the mixture to produce a white solid, dissolving the white solid in pentane to form a clear and colorless solution, filtering the mixture over a celite plug, and evaporating the solution under reduced pressure to obtain a solid In(III) N,N'-diisopropylacetamidinate precursor. This precursor has been further used to develop a novel atomic layer deposition technique for indium sulfide by dosing a reactor with the precursor, purging with nitrogen, dosing with dilute hydrogen sulfide, purging again with nitrogen, and repeating these steps to increase growth.

  3. Hydrogen sulfide determines HNO-induced stimulation of trigeminal afferents.

    Science.gov (United States)

    Wild, Vanessa; Messlinger, Karl; Fischer, Michael J M

    2015-08-18

    Endogenous NO and hydrogen sulfide form HNO, which causes CGRP release via TRPA1 channel activation in sensory nerves. In the present study, stimulation of intact trigeminal afferent neuron preparations with NO donors, Na2S or both was analyzed by measuring CGRP release as an index of mass activation. Combined stimulation was able to activate all parts of the trigeminal system and acted synergistic compared to stimulation with both substances alone. To investigate the contribution of both substances, we varied their ratio and tracked intracellular calcium in isolated neurons. Our results demonstrate that hydrogen sulfide is the rate-limiting factor for HNO formation. CGRP has a key role in migraine pathophysiology and HNO formation at all sites of the trigeminal system should be considered for this novel means of activation.

  4. Fractal characteristics of nanocrystalline indium and gallium sulfide particles

    Energy Technology Data Exchange (ETDEWEB)

    Sastry, P.U., E-mail: psastry@barc.gov.i [Solid State Physics Division, Mumbai 400085 (India); Dutta, Dimple P. [Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2009-11-13

    The structure of nano-sized powders of indium sulfide (In{sub 2}S{sub 3}) and gallium sulfide (Ga{sub 2}S{sub 3}), prepared by single source precursor route has been investigated by small angle X-ray scattering technique. The particle morphology shows interesting fractal nature. For In{sub 2}S{sub 3}, the nanoparticle aggregates show a mass fractal with fractal dimension 2.0 that increases with longer time of thermal treatment. Below the length scale of about 20 nm, the particles have a rough surface with a surface fractal dimension of 2.8. Unlike In{sub 2}S{sub 3}, structure of Ga{sub 2}S{sub 3} exhibits a single surface fractal over whole q-range of study. The estimated particle sizes are in range of 5-15 nm and the results are supported by transmission electron microscope.

  5. L-Cysteine-assisted Synthesis of Copper Gallium Sulfide Microspheres

    Institute of Scientific and Technical Information of China (English)

    LIANG Xiao-juan; ZHONG Jia-song; CAI Qian; HUANG Hai-yu; LIU Hai-tao; XIANG Wei-dong; SUN Jun-cai

    2012-01-01

    An effective L-cysteine-assisted synthetic route has been successfully developed to prepare copper gallium sulfide(CuGaS2) microspheres under solvothermal conditions with CuCI2-2H2O,GaCl3 and L-cysteine as source materials,in which L-cysteine was used as the sulfide source and eomplexing molecule.The experiments revealed that the synthesized sample was of a typical CuGaS2 tetragonal structure.Moreover,the prepared CuGaS2 crystals consisting of microspheres made up of nanoflakes,and the diameter of the nanoflakes was about 20 nm.Raman spectrum of the obtained CuGaS2 exhibits a high-intensity peak of the A1 mode at 306 cm-1.Meanwhile,a possible growth mechanism was proposed based on the investigations.

  6. LUMINESCENCE OF CADMIUM SULFIDE QUANTUM DOTS IN FLUOROPHOSPHATE GLASSES

    Directory of Open Access Journals (Sweden)

    Z. O. Lipatova

    2015-03-01

    Full Text Available Cadmium sulfide quantum dots are perspective materials in optics, medicine, biology and optoelectronics. Fluorophosphate glasses, doped with cadmium sulfide quantum dots, were examined in the paper. Heat treatment led to the formation of quantum dots with diameters equal to 2.8 nm, 3.0 nm and 3.8 nm. In view of such changes in the quantum dots size the fundamental absorption edge shift and the luminescence band are being displaced to the long wavelengths. Luminescence lifetime has been found to be dependent on the registration wavelength in the range from 450 to 700 nm. Obtained fluorophosphate glasses with CdS quantum dots can find their application as fluorescent materials with intensive luminescence band and long excited-state natural lifetime.

  7. Effect of hydrogen sulfide emissions on cement mortar specimens

    Energy Technology Data Exchange (ETDEWEB)

    Idriss, A. F. [Alberta Environment, Science and Technology Branch, Edmonton, AB (Canada); Negi, S. C.; Jofriet, J. C.; Haywoard, G. L. [Guelph Univ., Guelph, ON (Canada)

    2001-07-01

    Six different cement mortar specimens used in animal buildings, where they were exposed to hydrogen sulfide generated from anaerobic fermentation of manure during a period of one year, were investigated. Primary interest was on comparing the corrosion resistance of different cement mortar specimens under long term exposure to hydrogen sulfide. The impressed voltage technique was used to test the specimens in the laboratory. Results revealed that test specimens made with eight per cent silica fume cement replacement performed best and similar Portland cement mortar specimens with a water-cement ratio of 0.55 (PC55) the poorest. All other treatments, (Portland cement with a water to cement ratio of 045, Portland cement Type 50, Portland cement with fibre mesh and Portland cement Type 10 coated with linseed oil) all with water-cement ratios of 0.45, were less effective in preventing corrosion than silica fume replacement.

  8. Water purification by sulfide-containing activated carbon.

    Science.gov (United States)

    Oeste, F D; Haas, R; Kaminski, L

    2000-03-01

    We investigated a new kind of activated carbon named gaiasafe-Formstoff as an agent for powerful heavy metal reduction. This activated carbon contains highly dispersed sulfide compounds. Our investigations with lead containing wastewaters showed an outstanding metal sulfide precipitation power of the new agent. The lead reduction rates are independent of wastewater parameters like lead concentration and complexing agent concentration. Contacted as powder or as a fixed bed with wastewater gaiasafe-Formstoff showed the best cleaning capacity in comparison to all other agents tested. Investigations with gaiasafe-Formstoff about its ability to reduce the contents of further heavy metals in wastewater are under way. The gaiasafe-Formstoff reaction products with wastewater represent an energy-rich and raw material-rich resource when fed to metallurgical processes.

  9. Synthesis and characterization of cerium sulfide thin film

    Institute of Scientific and Technical Information of China (English)

    Ιshak Afsin Kariper

    2014-01-01

    Cerium sulfide (CexSy) polycrystalline thin film is coated with chemical bath deposition on substrates (commercial glass). Transmittance, absorption, optical band gap and refractive index are examined by using UV/VIS. Spectrum. The hexagonal form is observed in the structural properties in XRD. The structural and optical properties of cerium sulfide thin films are analyzed at different pH. SEM and EDX analyses are made for surface analysis and elemental ratio in films. It is observed that some properties of films changed with different pH values. In this study, the focus is on the observed changes in the properties of films. The pH values were scanned at 6–10. The optical band gap changed with pH between 3.40 to 3.60 eV. In addition, the film thickness changed with pH at 411 nm to 880 nm.

  10. 'Low-acid' sulfide oxidation using nitrate-enriched groundwater

    Science.gov (United States)

    Donn, Michael; Boxall, Naomi; Reid, Nathan; Meakin, Rebecca; Gray, David; Kaksonen, Anna; Robson, Thomas; Shiers, Denis

    2016-04-01

    Acid drainage (AMD/ARD) is undoubtedly one of the largest environmental, legislative and economic challenges facing the mining industry. In Australia alone, at least 60m is spent on AMD related issues annually, and the global cost is estimated to be in the order of tens of billions US. Furthermore, the challenge of safely and economically storing or treating sulfidic wastes will likely intensify because of the trend towards larger mines that process increasingly higher volumes of lower grade ores and the associated sulfidic wastes and lower profit margins. While the challenge of managing potentially acid forming (PAF) wastes will likely intensify, the industrial approaches to preventing acid production or ameliorating the effects has stagnated for decades. Conventionally, PAF waste is segregated and encapsulated in non-PAF tips to limit access to atmospheric oxygen. Two key limitations of the 'cap and cover' approach are: 1) the hazard (PAF) is not actually removed; only the pollutant linkage is severed; and, 2) these engineered structures are susceptible to physical failure in short-to-medium term, potentially re-establishing that pollutant linkage. In an effort to address these concerns, CSIRO is investigating a passive, 'low-acid' oxidation mechanism for sulfide treatment, which can potentially produce one quarter as much acidity compared with pyrite oxidation under atmospheric oxygen. This 'low-acid' mechanism relies on nitrate, rather than oxygen, as the primary electron accepter and the activity of specifically cultured chemolithoautotrophic bacteria and archaea communities. This research was prompted by the observation that, in deeply weathered terrains of Australia, shallow (oxic to sub-oxic) groundwater contacting weathering sulfides are commonly inconsistent with the geochemical conditions produced by ARD. One key characteristic of these aquifers is the natural abundance of nitrate on a regional scale, which becomes depleted around the sulfide bodies, and

  11. Fabrication and applications of copper sulfide (CuS) nanostructures

    Science.gov (United States)

    Shamraiz, Umair; Hussain, Raja Azadar; Badshah, Amin

    2016-06-01

    This review article presents different fabrication procedures (under the headlines of solvothermal routes, aerosol methods, solution methods and thermolysis), and applications (photocatalytic degradation, ablation of cancer cells, electrode material in lithium ion batteries and in gas sensing, organic solar cells, field emission properties, super capacitor applications, photoelectrochemical performance of QDSCs, photocatalytic reduction of organic pollutants, electrochemical bio sensing, enhanced PEC characteristics of pre-annealed CuS film electrodes) of copper sulfide (Covellite).

  12. Reconstruction of the electron spectrum in a metal hydrogen sulfide

    Science.gov (United States)

    Kudryashov, N. A.; Kutukov, A. A.; Mazur, E. A.

    2017-01-01

    Generalized Eliashberg theory of the normal properties of a metal electron-phonon system with a non constant electron density of states has been used to study the effect of the conduction band reconstruction. The electron density of states of the metallic phase of the hydrogen sulfide renormalized by the strong electron-phonon coupling at a pressure of P = 225 GPa has been calculated. It has been found that the reconstructed conduction band contains a series of narrow energy pockets.

  13. Laboratory SIP signatures associated with oxidation of disseminated metal sulfides

    Science.gov (United States)

    Placencia-Gómez, Edmundo; Slater, Lee; Ntarlagiannis, Dimitrios; Binley, Andrew

    2013-05-01

    Oxidation of metal sulfide minerals is responsible for the generation of acidic waters rich in sulfate and metals. When associated with the oxidation of sulfide ore mine waste deposits the resulting pore water is called acid mine drainage (AMD); AMD is a known environmental problem that affects surface and ground waters. Characterization of oxidation processes in-situ is challenging, particularly at the field scale. Geophysical techniques, spectral induced polarization (SIP) in particular, may provide a means of such investigation. We performed laboratory experiments to assess the sensitivity of the SIP method to the oxidation mechanisms of common sulfide minerals found in mine waste deposits, i.e., pyrite and pyrrhotite, when the primary oxidant agent is dissolved oxygen. We found that SIP parameters, e.g., phase shift, the imaginary component of electrical conductivity and total chargeability, decrease as the time of exposure to oxidation and oxidation degree increase. This observation suggests that dissolution-depletion of the mineral surface reduces the capacitive properties and polarizability of the sulfide minerals. However, small increases in the phase shift and imaginary conductivity do occur during oxidation. These transient increases appear to correlate with increases of soluble oxidizing products, e.g., Fe2 + and Fe3 + in solution; precipitation of secondary minerals and the formation of a passivating layer to oxidation coating the mineral surface may also contribute to these increases. In contrast, the real component of electrical conductivity associated with electrolytic, electronic and interfacial conductance is sensitive to changes in the pore fluid chemistry as a result of the soluble oxidation products released (Fe2 + and Fe3 +), particularly for the case of pyrrhotite minerals.

  14. Aromatic and heterocyclic perfluoroalkyl sulfides. Methods of preparation

    Directory of Open Access Journals (Sweden)

    Vladimir N. Boiko

    2010-08-01

    Full Text Available This review covers all of the common methods for the syntheses of aromatic and heterocyclic perfluoroalkyl sulfides, a class of compounds which is finding increasing application as starting materials for the preparation of agrochemicals, pharmaceutical products and, more generally, fine chemicals. A systematic approach is taken depending on the mode of incorporation of the SRF groups and also on the type of reagents used.

  15. Hydrogen sulfide metabolism regulates endothelial solute barrier function

    Directory of Open Access Journals (Sweden)

    Shuai Yuan

    2016-10-01

    Full Text Available Hydrogen sulfide (H2S is an important gaseous signaling molecule in the cardiovascular system. In addition to free H2S, H2S can be oxidized to polysulfide which can be biologically active. Since the impact of H2S on endothelial solute barrier function is not known, we sought to determine whether H2S and its various metabolites affect endothelial permeability. In vitro permeability was evaluated using albumin flux and transendothelial electrical resistance. Different H2S donors were used to examine the effects of exogenous H2S. To evaluate the role of endogenous H2S, mouse aortic endothelial cells (MAECs were isolated from wild type mice and mice lacking cystathionine γ-lyase (CSE, a predominant source of H2S in endothelial cells. In vivo permeability was evaluated using the Miles assay. We observed that polysulfide donors induced rapid albumin flux across endothelium. Comparatively, free sulfide donors increased permeability only with higher concentrations and at later time points. Increased solute permeability was associated with disruption of endothelial junction proteins claudin 5 and VE-cadherin, along with enhanced actin stress fiber formation. Importantly, sulfide donors that increase permeability elicited a preferential increase in polysulfide levels within endothelium. Similarly, CSE deficient MAECs showed enhanced solute barrier function along with reduced endogenous bound sulfane sulfur. CSE siRNA knockdown also enhanced endothelial junction structures with increased claudin 5 protein expression. In vivo, CSE genetic deficiency significantly blunted VEGF induced hyperpermeability revealing an important role of the enzyme for barrier function. In summary, endothelial solute permeability is critically regulated via exogenous and endogenous sulfide bioavailability with a prominent role of polysulfides.

  16. Delivering carbide ligands to sulfide-rich clusters.

    Science.gov (United States)

    Reinholdt, Anders; Herbst, Konrad; Bendix, Jesper

    2016-02-01

    The propensity of the terminal ruthenium carbide Ru(C)Cl2(PCy3)2 (RuC) to form carbide bridges to electron-rich transition metals enables synthetic routes to metal clusters with coexisting carbide and sulfide ligands. Electrochemical experiments show the Ru≡C ligand to exert a relatively large electron-withdrawing effect compared with PPh3, effectively shifting redox potentials.

  17. The anodic behavior of iron in hydrogen sulfide solutions

    Energy Technology Data Exchange (ETDEWEB)

    Pound, B.G. (SRI International, Menlo Park, CA (USA)); Wright, G.A.; Sharp, R.M. (Auckland Univ. (New Zealand). Dept. of Chemistry)

    1989-05-01

    The anodic behavior of iron in 0.032 mol . L/sup -1/ NaCl/0.003 mol . L/sup -1/ NaHCO/sub 3/ and 1 mol . L/sup -1/ Na/sub 2/SO/sub 4//0.003 mol . L/sup -1/ NaHCO/sub 3/ solutions containing 0.05 mol . L/sup -1/ H/sub 2/S at ambient temperature was studied using cyclic voltammetry and the potentiostatic technique. In both solutions, a nonprotective film of mackinawite (Fe/sub 1+chi/S) was formed on the iron, but the film growth kinetics differ for the two solutions. The film growth in chloride solutions does not appear to follow a conventional type of model for multilayer fils whereas the formation of the film in sulfate solutions can be represented in terms of a pre-resistance model. At more anodic potentials, the mackinawite is oxidized to a higher sulfide, possibly pyrite (FeS/sub 2/), as suggested from a comparison of the anodic and cathodic peak potentials with the equilibrium potential. The formation of the higher sulfide(s) in the chloride solution appears to follow a similar film growth mechanism to that for mackinawite, whereas it is not clear whether this is the case for the sulfate solution.

  18. Sulfide Capacity in Ladle Slag at Steelmaking Temperatures

    Science.gov (United States)

    Allertz, Carl; Sichen, Du

    2015-12-01

    Sulfide capacity measurements were conducted at 1823 K and 1873 K (1550 °C and 1600 °C) for the quaternary Al2O3-CaO-MgO-SiO2 system, for typical compositions used in the ladle in steelmaking. A copper-slag equilibrium was used under controlled oxygen and sulfur potentials. The sulfide capacity is strongly dependent on the composition and it was found to increase with the basic oxides, while it decreases with increase of the acidic components. It was found that CaO is more effective in holding sulfur in the slag compared to MgO when replacing SiO2. For the present slag compositions, Al2O3 and SiO2 behaved similar with respect to sulfur, and no considerable effect could be recorded when replacing one for the other. The sulfide capacity was also found to be strongly dependent on the temperature, increasing with temperature. The present results were compared with industrial data from the ladle, after vacuum treatment, and they were in good agreement.

  19. Protective Effects of Hydrogen Sulfide in the Ageing Kidney.

    Science.gov (United States)

    Hou, Cui-Lan; Wang, Ming-Jie; Sun, Chen; Huang, Yong; Jin, Sheng; Mu, Xue-Pan; Chen, Ying; Zhu, Yi-Chun

    2016-01-01

    Aims. The study aimed to examine whether hydrogen sulfide (H2S) generation changed in the kidney of the ageing mouse and its relationship with impaired kidney function. Results. H2S levels in the plasma, urine, and kidney decreased significantly in ageing mice. The expression of two known H2S-producing enzymes in kidney, cystathionine γ-lyase (CSE) and cystathionine-β-synthase (CBS), decreased significantly during ageing. Chronic H2S donor (NaHS, 50 μmol/kg/day, 10 weeks) treatment could alleviate oxidative stress levels and renal tubular interstitial collagen deposition. These protective effects may relate to transcription factor Nrf2 activation and antioxidant proteins such as HO-1, SIRT1, SOD1, and SOD2 expression upregulation in the ageing kidney after NaHS treatment. Furthermore, the expression of H2S-producing enzymes changed with exogenous H2S administration and contributed to elevated H2S levels in the ageing kidney. Conclusions. Endogenous hydrogen sulfide production in the ageing kidney is insufficient. Exogenous H2S can partially rescue ageing-related kidney dysfunction by reducing oxidative stress, decreasing collagen deposition, and enhancing Nrf2 nuclear translocation. Recovery of endogenous hydrogen sulfide production may also contribute to the beneficial effects of NaHS treatment.

  20. Structural studies of copper sulfide films: effect of ambient atmosphere

    Directory of Open Access Journals (Sweden)

    Manisha Kundu et al

    2008-01-01

    Full Text Available We examined the structural properties of copper sulfide films as a function of the sulfurization time of 70-nm-thick Cu films. Copper sulfide films with various phases such as mixed metallic Cu-chalcocite, chalcocite, roxbyite, and covellite phases were formed with increasing sulfurization time. To evaluate the structural stability of various films, all the films were exposed to the ambient atmosphere for the same amount of time. Although the phase structure and stoichiometry of the films were maintained at a greater depth, the near-surface region of the films was oxidized and covered with overlayers of oxide, hydroxide, and/or sulfate species due to the exposure and reaction with the ambient atmosphere. The oxygen uptake and its reactivity with the copper sulfide film surfaces were enhanced with increasing sulfur content of the films. In addition, the type of divalent state of copper formed on the film surfaces depended on the phase structure, composition, and stoichiometry of the films.

  1. Selective Facet Reactivity During Cation Exchange in Cadmium Sulfide Nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Sadtler, Bryce; Demchenko, Denis; Zheng, Haimei; Hughes, Steven; Merkle, Maxwell; Dahmen, Ulrich; Wang, Lin-Wang; Alivisatos, A. Paul

    2008-12-18

    The partial transformation of ionic nanocrystals through cation exchange has been used to synthesize nanocrystal heterostructures. We demonstrate that the selectivity for cation exchange to take place at different facets of the nanocrystal plays an important role in determining the resulting morphology of the binary heterostructure. In the case of copper I (Cu+) cation exchange in cadmium sulfide (CdS) nanorods, the reaction starts preferentially at the ends of the nanorods such that copper sulfide (Cu2S) grows inwards from either end. The resulting morphology is very different from the striped pattern obtained in our previous studies of silver I (Ag+) exchange in CdS nanorods where non-selective nucleation of silver sulfide (Ag2S) occurs. From interface formation energies calculated for several models of epitaxialconnections between CdS and Cu2S or Ag2S, we infer the relative stability of each interface during the nucleation and growth of Cu2S or Ag2S within the CdS nanorods. The epitaxial connections of Cu2S to the end facets of CdS nanorods minimize the formation energy, making these interfaces stable throughout the exchange reaction. However, as the two end facets of wurtzite CdS nanorods are crystallographically nonequivalent, asymmetric heterostructures can be produced.

  2. Glacial weathering, sulfide oxidation, and global carbon cycle feedbacks

    Science.gov (United States)

    Torres, Mark A.; Moosdorf, Nils; Hartmann, Jens; Adkins, Jess F.; West, A. Joshua

    2017-08-01

    Connections between glaciation, chemical weathering, and the global carbon cycle could steer the evolution of global climate over geologic time, but even the directionality of feedbacks in this system remain to be resolved. Here, we assemble a compilation of hydrochemical data from glacierized catchments, use this data to evaluate the dominant chemical reactions associated with glacial weathering, and explore the implications for long-term geochemical cycles. Weathering yields from catchments in our compilation are higher than the global average, which results, in part, from higher runoff in glaciated catchments. Our analysis supports the theory that glacial weathering is characterized predominantly by weathering of trace sulfide and carbonate minerals. To evaluate the effects of glacial weathering on atmospheric pCO2, we use a solute mixing model to predict the ratio of alkalinity to dissolved inorganic carbon (DIC) generated by weathering reactions. Compared with nonglacial weathering, glacial weathering is more likely to yield alkalinity/DIC ratios less than 1, suggesting that enhanced sulfide oxidation as a result of glaciation may act as a source of CO2 to the atmosphere. Back-of-the-envelope calculations indicate that oxidative fluxes could change ocean–atmosphere CO2 equilibrium by 25 ppm or more over 10 ky. Over longer timescales, CO2 release could act as a negative feedback, limiting progress of glaciation, dependent on lithology and the concentration of atmospheric O2. Future work on glaciation–weathering–carbon cycle feedbacks should consider weathering of trace sulfide minerals in addition to silicate minerals.

  3. Mechanism of heterogeneous reaction of carbonyl sulfide on magnesium oxide.

    Science.gov (United States)

    Liu, Yongchun; He, Hong; Xu, Wenqing; Yu, Yunbo

    2007-05-24

    Heterogeneous reaction of carbonyl sulfide (OCS) on magnesium oxide (MgO) under ambient conditions was investigated by in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), quadrupole mass spectrometer (QMS), and density functional theory (DFT) calculations. It reveals that OCS can be catalytically hydrolyzed by surface hydroxyl on MgO to produce carbon dioxide (CO2) and hydrogen sulfide (H2S), and then H2S can be further catalytically oxidized by surface oxygen or gaseous oxygen on MgO to form sulfite (SO3(2-)) and sulfate (SO4(2-)). Hydrogen thiocarbonate (HSCO2-) was found to be the crucial intermediate. Surface hydrogen sulfide (HS), sulfur dioxide (SO2), and surface sulfite (SO3(2-)) were also found to be intermediates for the formation of sulfate. Furthermore, the surface hydroxyl contributes not only to the formation of HSCO2- but also to HSCO2- decomposition. On the basis of experimental results, the heterogeneous reaction mechanism of OCS on MgO was discussed.

  4. Chemical Precipitation Synthesis and Thermoelectric Properties of Copper Sulfide

    Science.gov (United States)

    Wu, Sixin; Jiang, Jing; Liang, Yinglin; Yang, Ping; Niu, Yi; Chen, Yide; Xia, Junfeng; Wang, Chao

    2017-04-01

    Earth-abundant copper sulfide compounds have been intensively studied as potential thermoelectric materials due to their high dimensionless figure of merit ZT values. They have a unique phonon-liquid electron-crystal model that helps to achieve high thermoelectric performance. Many methods, such as melting and ball-milling, have been adopted to synthesize this copper sulfide compound, but they both use expensive starting materials with high purity. Here, we develop a simple chemical precipitation approach to synthesize copper sulfide materials through low-cost analytically pure compounds as the starting materials. A high ZT value of 0.93 at 800 K was obtained from the samples annealed at 1273 K. Its power factor is around 8.0 μW cm-1 K-2 that is comparable to the highest record reported by traditional methods. But, the synthesis here has been greatly simplified with reduced cost, which will be of great benefit to the potential mass production of thermoelectric devices. Furthermore, this method can be applied to the synthesis of other sulfur compound thermoelectric materials.

  5. Sulfide ceramics in molten-salt electrolyte batteries

    Energy Technology Data Exchange (ETDEWEB)

    Kaun, T.D.; Hash, M.C.; Simon, D.R.

    1995-06-01

    Sulfide ceramics are finding application in the manufacture of advanced batteries with molten salt electrolyte. Use of these ceramics as a peripheral seal component has permitted development of bipolar Li/FeS{sub 2} batteries. This bipolar battery has a molten lithium halide electrolyte and operates at 400 to 450C. Initial development and physical properties evaluations indicate the ability to form metal/ceramic bonded seal (13-cm ID) components for use in high-temperature corrosive environments. These sealants are generally CaAl{sub 2}S{sub 4}-based ceramics. Structural ceramics (composites with oxide or nitride fillers), highly wetting sealant formulations, and protective coatings are also being developed. Sulfide ceramics show great promise because of their relatively low melting point, high-temperature viscous flow, chemical stability, high-strength bonding, and tailored coefficients of thermal expansion. Our methodology of generating laminated metal/ceramic pellets (e.g., molybdenum/sulfide ceramic/molybdenum) with which to optimize materials formulation and seal processing is described.

  6. Impact electrochemistry: colloidal metal sulfide detection by cathodic particle coulometry.

    Science.gov (United States)

    Lim, Chee Shan; Pumera, Martin

    2015-10-28

    The determination of the size and concentration of colloidal nano and microparticles is of paramount importance to modern nanoscience. Application of the particle collision technique on metal and metal oxide nanoparticles has been intensively explored over the past decade owing to its ability to determine the particle size and concentration via reactions including the inherent oxidation or the reduction of nanoparticles as well as surface reactions catalysed by the nanoparticles. Transition metal dichalcogenide particles were previously quantified using the anodic (oxidative) particle coulometry method. Here we show that cathodic (reductive) particle coulometry can be favorably used for the detection of metal sulfide colloidal particles. The detection of sulfides of cobalt and lead was performed using the particle collision technique in this work. The presence of spikes confirmed the viability of detecting new and larger particles from compounds using reductive (cathodic) potentials. Such an expansion of the impact particle coulometry method will be useful and applicable to the determination of concentration and size of colloidal metal sulfide nanoparticles in general.

  7. Benzothiazole sulfide compatibilized polypropylene/halloysite nanotubes composites

    Energy Technology Data Exchange (ETDEWEB)

    Liu Mingxian [Department of Polymer Materials and Engineering, South China University of Technology, Guangzhou 510640 (China); Guo Baochun, E-mail: psbcguo@scut.edu.cn [Department of Polymer Materials and Engineering, South China University of Technology, Guangzhou 510640 (China); Lei Yanda; Du Mingliang; Jia Demin [Department of Polymer Materials and Engineering, South China University of Technology, Guangzhou 510640 (China)

    2009-02-15

    Clay-philic benzothiazole sulfide, capable of donating electrons, is grafted onto polypropylene (PP) backbones when N-cyclohexyl-2-benzothiazole sulfonamide (CBS), a commonly used accelerator in the tire industry, is included in the processing of PP/halloysite nanotubes (HNTs) composites. CBS decomposes at elevated temperature and yields benzothiazole sulfide radicals, which react with the PP polymeric free radicals generated during the processing of the composites. On the other hand, the benzothiazole group of CBS is reactive to HNTs via electron transferring. The compatibilization between HNTs and PP is thus realized via interfacial grafting and electron transferring mechanism. The interfacial interactions in the compatibilized systems were fully characterized. Compared with the control sample, the dispersion of HNTs and the interfacial bonding are enhanced substantially in the compatibilized composites. The significantly improved mechanical properties and thermal properties of benzothiazole sulfide compatibilized PP/HNTs composites are correlated to the enhanced interfacial property. The present work demonstrates a novel interfacial design via interfacial grafting/electron transferring for the compatibilization of PP/clay composites.

  8. Solubility Measurements and Modeling of Zinc, Lead and Iron Sulfides at High Temperatures and High Pressures

    DEFF Research Database (Denmark)

    Carolina Figueroa Murcia, Diana; Fosbøl, Philip Loldrup; Thomsen, Kaj

    Solubility measurements of sulfides in aqueous solutions are necessary to understand the behaviour of these scaling minerals in geothermal and oil reservoirs. The low solubility levels of Zinc Sulfide (ZnS), Lead Sulfide (PbS) and Iron Sulfide (FeS) make the solubility measurements a challenging...... task. Consequently existing data are rare and scattered. The aim of this work is to develop a reliable experimental procedure and to measure solubility of sulfides at high temperature and pressures. Additionally the experimental data are used for estimation of the solid-liquid equilibrium using...... oxygen atmosphere to avoid the risk of oxidation of sulfide minerals. The solution is kept in an equilibrium cell at constant temperature and pressure with continuous stirring. The concentration of Zn2+, Pb2+, Fe2+ and S2- are measured using Inductively Coupled Plasma Optical Emission spectrometry (ICP...

  9. Alkaline sulfide pretreatment of an antimonial refractory Au-Ag ore for improved cyanidation

    Science.gov (United States)

    Alp, Ibrahim; Celep, Oktay; Deveci, Haci

    2010-11-01

    This paper presents the alkaline sulfide pretreatment of an antimonial refractory gold and silver ore. In the ore, gold occurs mainly as gold-silver alloys and as associated with quartz and framboidal pyrite grains, and, to a small extent, as the inclusions within antimonial sulfides. Silver is present extensively as antimonial sulfides such as andorite. Alkaline sulfide pretreatment was shown to allow the decomposition of the antimonial sulfide minerals (up to 98% Sb removal) and to remarkably improve the amenability of gold (e.g., from silver (e.g., from leaching. An increase in reagent concentration (1-4 mol/L Na2S or NaOH) and temperature (20-80°C), and a decrease in particle size seem to produce an enhancing effect on metal extraction. These findings suggest that alkaline sulfide leaching can be suitably used as a chemical pretreatment method prior to the conventional cyanidation for antimonial refractory gold and silver ores.

  10. Biogenesis of reactive sulfur species for signaling by hydrogen sulfide oxidation pathways.

    Science.gov (United States)

    Mishanina, Tatiana V; Libiad, Marouane; Banerjee, Ruma

    2015-07-01

    The chemical species involved in H2S signaling remain elusive despite the profound and pleiotropic physiological effects elicited by this molecule. The dominant candidate mechanism for sulfide signaling is persulfidation of target proteins. However, the relatively poor reactivity of H2S toward oxidized thiols, such as disulfides, the low concentration of disulfides in the reducing milieu of the cell and the low steady-state concentration of H2S raise questions about the plausibility of persulfide formation via reaction between an oxidized thiol and a sulfide anion or a reduced thiol and oxidized hydrogen disulfide. In contrast, sulfide oxidation pathways, considered to be primarily mechanisms for disposing of excess sulfide, generate a series of reactive sulfur species, including persulfides, polysulfides and thiosulfate, that could modify target proteins. We posit that sulfide oxidation pathways mediate sulfide signaling and that sulfurtransferases ensure target specificity.

  11. Three enzymatic activities catalyze the oxidation of sulfide to thiosulfate in mammalian and invertebrate mitochondria.

    Science.gov (United States)

    Hildebrandt, Tatjana M; Grieshaber, Manfred K

    2008-07-01

    Hydrogen sulfide is a potent toxin of aerobic respiration, but also has physiological functions as a signalling molecule and as a substrate for ATP production. A mitochondrial pathway catalyzing sulfide oxidation to thiosulfate in three consecutive reactions has been identified in rat liver as well as in the body-wall tissue of the lugworm, Arenicola marina. A membrane-bound sulfide : quinone oxidoreductase converts sulfide to persulfides and transfers the electrons to the ubiquinone pool. Subsequently, a putative sulfur dioxygenase in the mitochondrial matrix oxidizes one persulfide molecule to sulfite, consuming molecular oxygen. The final reaction is catalyzed by a sulfur transferase, which adds a second persulfide from the sulfide : quinone oxidoreductase to sulfite, resulting in the final product thiosulfate. This role in sulfide oxidation is an additional physiological function of the mitochondrial sulfur transferase, rhodanese.

  12. When can Electrochemical Techniques give Reliable Corrosion Rates on Carbon Steel in Sulfide Media?

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel; Hemmingsen, Tor; Nielsen, Lars Vendelbo

    2005-01-01

    Effects of film formation on carbon steel in hydrogen sulfide media may corrupt corrosion rate monitoring by electrochemical techniques. Electrochemical data from hydrogen sulfide solutions, biological sulfide media and natural sulfide containing geothermal water have been collected and the process...... corrosion rates, but this effect may not be detected if rates are already overestimated. It is concluded that electrochemical techniques can be used for corrosion rate monitoring in som hydrogen sulfide media, but care must be taken when choosing the scan rates, and it is important to realize when direct...... in combination with ferrous sulfide corrosion products cover the steel surface. Corrosion rates can be overestimated by a factor of 10 to 100 with electrochemical techniques - both by linear polarization resistance (LPR) and electrochemical impedance spectroscopy (EIS). Oxygen entering the system accelerates...

  13. Effect of Sulfide Concentration on Copper Corrosion in Anoxic Chloride-Containing Solutions

    Science.gov (United States)

    Kong, Decheng; Dong, Chaofang; Xu, Aoni; Man, Cheng; He, Chang; Li, Xiaogang

    2017-02-01

    The structure and property of passive film on copper are strongly dependent on the sulfide concentration; based on this, a series of electrochemical methods were applied to investigate the effect of sulfide concentration on copper corrosion in anaerobic chloride-containing solutions. The cyclic voltammetry and x-ray photoelectron spectroscopy analysis demonstrated that the corrosion products formed on copper in anaerobic sulfide solutions comprise Cu2S and CuS. And the corrosion resistance of copper decreased with increasing sulfide concentration and faster sulfide addition, owing to the various structures of the passive films observed by the atomic force microscope and scanning electron microscope. A p-type semiconductor character was obtained under all experimental conditions, and the defect concentration, which had a magnitude of 1022-1023 cm-3, increased with increasing sulfide concentration, resulting in a higher rate of both film growth and dissolution.

  14. Iron sulfides in mudstones within the carbonaceous sequence of Donets Basin

    Energy Technology Data Exchange (ETDEWEB)

    Kizilshtein, L.Y.; Nastavkin, A.V. [Rostov State University, Rostov Na Donu (Russian Federation)

    2003-02-01

    The genesis of local compact segregations of iron sulfide (pyrite) in mudstones at the roof of some coal seams in the Donets Basin (Donbas) is examined. Arguments presented in the work show that sulfides were formed as a result of bacterial sulfate reduction and hydrogen sulfide generation in zones of organic matter concentration. The lack of any signs of influx of alien components testifies to in situ sulfide accumulations at the syngenetic or early diagenetic stage in bottom sediments of the basin. The shape and structure of pyrite segregations suggest that they could be 'sulfide bioherms' occasionally subjected to mechanical deformation in a liquid mud under the influence of gravitational force or external mechanical (possibly seismic) loads. The obtained data can serve as an additional source of information pertaining to the formation conditions of sulfide ore deposits.

  15. Modeling of hydrogen sulfide oxidation in concrete corrosion products from sewer pipes.

    Science.gov (United States)

    Jensen, Henriette Stokbro; Nielsen, Asbjørn Haaning; Hvitved-Jacobsen, Thorkild; Vollertsen, Jes

    2009-04-01

    Abiotic and biotic oxidation of hydrogen sulfide related to concrete corrosion was studied in corrosion products originating from a sewer manhole. The concrete corrosion products were suspended in an acidic solution, mimicking the conditions in the pore water of corroded concrete. The removal of hydrogen sulfide and dissolved oxygen was measured in parallel in the suspension, upon which the suspension was sterilized and the measurement repeated. The results revealed the biotic oxidation to be fast compared with the abiotic oxidation. The stoichiometry of the hydrogen sulfide oxidation was evaluated using the ratio between oxygen and hydrogen sulfide uptake. The ratio for the biotic oxidation pointed in the direction of elemental sulfur being formed as an intermediate in the oxidation of hydrogen sulfide to sulfuric acid. The experimental results were applied to suggest a hypothesis and a mathematical model describing the hydrogen sulfide oxidation pathway in a matrix of corroded concrete.

  16. Aerobic and anaerobic transformations of sulfide in a sewer system--field study and model simulations.

    Science.gov (United States)

    Nielsen, Asbjørn Haaning; Vollertsen, Jes; Jensen, Henriette Stokbro; Madsen, Heidi Ina; Hvitved-Jacobsen, Thorkild

    2008-01-01

    The formation and fate of sulfide in a force main and a downstream-located gravity sewer were investigated in an extensive field study. Sulfide formation in the force main was significant. However, during 14 minutes of transport in the gravity sewer, the sulfide concentration decreased 30%, on average. An application of a conceptual sewer process model for simulating the formation and fate of sulfide was demonstrated. Overall, the model predicted that approximately 90% of the decrease of the sulfide concentration in the gravity sewer was the result of sulfide oxidation and that only a small fraction entered the sewer atmosphere, causing odor and corrosion. Even so, the model predicted concrete corrosion rates of up to 1.2 mm/y in the gravity sewer section.

  17. Microbial control of the production of hydrogen sulfide by sulfate-reducing bacteria.

    Science.gov (United States)

    Montgomery, A D; McLnerney, M J; Sublette, K L

    1990-03-01

    A sulfide-resistant ctrain of Thiobacillus denitrificans, strain F, prevented the accumulation of sulfide by Desulfovibrio desulfuricans when both organisms were grown in liquid medium or in Berea sandstone cores. The wild-type strain of T. denitrificans did not prevent the accumulation of sulfide produced by D. desulfuricans. Strain F also prevented the accumulation of sulfide by a mixed population of sulfate-reducing bacteria enriched from an oil field brine. Fermentation balances showed that strain F stoichiometrically oxidized the sulfide produced by D. desulfuricans and the oil field brine enrichment to sulfate. These data suggest that strain F would be effective in controlling sulfide production in oil reservoirs and other environments.

  18. Metabolism of S-(2-chloro-1,1,2-trifluoroethyl)-L-cysteine to hydrogen sulfide and the role of hydrogen sulfide in S-(2-chloro-1,1,2-trifluoroethyl)-L-cysteine-induced mitochondrial toxicity.

    Science.gov (United States)

    Banki, K; Elfarra, A A; Lash, L H; Anders, M W

    1986-07-31

    The nephrotoxic cysteine S-conjugate S-(2-chloro-1,1,2-trifluoroethyl)-L-cysteine (CTFC) is metabolized by kidney homogenates and subcellular fractions to pyruvate and a reactive thiol, which is cytotoxic and partially decomposes to yield hydrogen sulfide and thiosulfate. Although hydrogen sulfide is a potent mitochondrial poison, the mitochondrial toxicity of CTFC is not attributable to hydrogen sulfide formation, as shown by different sites of inhibition of mitochondrial respiration by CTFC and hydrogen sulfide. The efficient mitochondrial oxidation of hydrogen sulfide apparently serves to protect mitochondria against the toxic effects of hydrogen sulfide generated from CTFC.

  19. Synthesis, characterization, and reactivity of sulfided hexanuclear molybdenum cluster compounds

    Energy Technology Data Exchange (ETDEWEB)

    Spink, D.

    1990-09-21

    Hexanuclear molybdenum clusters with mixed chloride and sulfide bridging ligands were prepared by reacting {alpha}-MoCl{sub 2} with sodium hydrosulfide in the presence of sodium butoxide. The resulting species, Mo{sub 6}Cl{sub (8-x)}S{sub x}{center dot}npy(x {congruent} 3.6, n {congruent} 4, py = pyridine), was pyrophoric and insoluble. The mixed sulfide chloride cluster species Mo{sub 6}S{sub 4}Cl{sub 4}{center dot}6OPEt{sub 3} and Mo{sub 6}S{sub {approximately}5}Cl{sub {approximately}3}{center dot}6PEt{sub 3} and Mo{sub 6}S{sub 8}{center dot}6PEt{sub 3} were isolated and characterized. Phosphorus-31 nuclear magnetic resonance, electron paramagnetic resonance, and UV/visible spectra were obtained for each fraction. The completely sulfided cluster, Mo{sub 6}S{sub 8}{center dot}6PEt{sub 3}, was prepared similarly and used in various experiments as a possible precursor to Chevrel phase materials of the type Mo{sub 6}S{sub 8}or M{sub n}Mo{sub 6}S{sub 8}. With the goal of removing all of the triethylphosphine ligands, Mo{sub 6}S{sub 8}{center dot}6PEt{sub 3} was reacted with the transition metal carbonyls molybdenum hexacarbonyl and dicobalt octacarbonyl. Reaction on the molecular sulfide cluster with copper(I) chloride in toluene gave a completely insoluble product. The reaction of Mo{sub 6}S{sub 8}{center dot}6PEt{sub 3} with propylene sulfide gave a product whose infrared spectra showed only very weak peaks associated with coordinated triethylphosphine. The elemental analysis of this product fit the formula Mo{sub 6}S{sub 8}{center dot}5SPEt{sub 3}. Reactivity of the outer ligands of the Mo{sub 6}S{sub 8}{center dot}npy and Mo{sub 6}S{sub 8}{center dot}(6{minus}x)PrNH{sub x} clusters were investigated. Crystalline Mo{sub 6}S{sub 8}{center dot}6THT was recovered from the reaction of the n-propylamine derivative with THT. A crystal structure determination was done. 87 refs., 12 fig., 15 tabs.

  20. Inhibition of Sulfide Mineral Oxidation by Surface Coating Agents: Batch

    Science.gov (United States)

    Choi, J.; Ji, M. K.; Yun, H. S.; Park, Y. T.; Gee, E. D.; Lee, W. R.; Jeon, B.-H.

    2012-04-01

    Mining activities and mineral industries have impacted on rapid oxidation of sulfide minerals such as pyrite (FeS2) which leads to Acid Mine Drainage (AMD) formation. Some of the abandoned mines discharge polluted water without proper environmental remediation treatments, largely because of financial constraints in treating AMD. Magnitude of the problem is considerable, especially in countries with a long history of mining. As metal sulfides become oxidized during mining activities, the aqueous environment becomes acid and rich in many metals, including iron, lead, mercury, arsenic and many others. The toxic heavy metals are responsible for the environmental deterioration of stream, groundwater and soils. Several strategies to remediate AMD contaminated sites have been proposed. Among the source inhibition and prevention technologies, microencapsulation (coating) has been considered as a promising technology. The encapsulation is based on inhibition of O2 diffusion by surface coating agent and is expected to control the oxidation of pyrite for a long time. Potential of several surface coating agents for preventing oxidation of metal sulfide minerals from both Young-Dong coal mine and Il-Gwang gold mine were examined by conducting batch experiments and field tests. Powdered pyrite as a standard sulfide mineral and rock samples from two mine outcrops were mixed with six coating agents (KH2PO4, MgO and KMnO4 as chemical agents, and apatite, cement and manganite as mineral agents) and incubated with oxidizing agents (H2O2 or NaClO). Batch experiments with Young-Dong coal mine samples showed least SO42- production in presence of KMnO4 (16% sulfate production compared to no surface coating agents) or cement (4%) within 8 days. In the case of Il-Gwang mine samples, least SO42- production was observed in presence of KH2PO4 (8%) or cement (2%) within 8 days. Field-scale pilot tests at Il-Gwang site also showed that addition of KH2PO4 decreased sulfate production from 200 to

  1. High Temperature Corrosion of Fe-C-S Cast Irons in Oxidizing and Sulfidizing Atmospheres

    Institute of Scientific and Technical Information of China (English)

    Thuan-Dinh NGUYEN; Dong-Bok LEE

    2008-01-01

    The corrosion behavior of spheroidal graphite and flake graphite cast irons was studied in oxidizing and sulfidizing atmospheres between 600 and 800℃ for 50 h. The corrosion rate in the sulfidizing atmosphere was faster than that in air above 700℃, due to the formation of the Feo.975S sulfide. The corrosion rate of the spheroidal graphite cast iron was similar to that of the flake graphite cast iron.

  2. Regarding "Sulfide Capacity in Ladle Slag at Steelmaking Temperatures," C. Allertz, Du Sichen; MMTB 2015 December

    Science.gov (United States)

    Pelton, Arthur; Kang, Youn-Bae

    2016-09-01

    Allertz and Sichen measured sulfide contents of slags in equilibrium with Cu-S solutions. Results are in very good agreement with calculations by FactSage whose databases were developed by modeling other sets of data obtained under different conditions. However, when results are reported as sulfide capacities, significant errors may result if these are used to calculate sulfide contents at oxygen and sulfur potentials which differ from those of the experiments and/or are fixed by different means.

  3. Research of the Plasma Sulfide Layer Formed on the Nitrocarburizing Layer

    Institute of Scientific and Technical Information of China (English)

    LI Xin; MA Shi-ning; HU Chun-hua; QIU Ji; HUANG Yuan-lin

    2004-01-01

    Low-temperature sulfurizing after nitrocarburizing are compared with only low-temperature sulfurizing on the surface of CrMoCu alloyed cast iron, the surface morphologies and microstructures are investigated by SEM and EDS.Results show that under proper treatment parameters, there are sulfide layer on both of the surfaces, and can more easily obtain sulfide layers on the surface of nitrocarburizing. Forming mechanism of sulfides were also studied elementarily.

  4. The impact of electrogenic sulfide oxidation on elemental cycling and solute fluxes in coastal sediment

    OpenAIRE

    Rao, A.M.F.; Malkin, S.Y.; Hidalgo-Martinez, S.; Meysman, Filip

    2016-01-01

    Filamentous sulfide oxidizing cable bacteria are capable of linking the oxidation of free sulfide in deep anoxic layers of marine sediments to the reduction of oxygen or nitrate in surface sediments by conducting electrons over centimeter-scale distances. Previous studies have shown that this newly discovered microbial process, referred to as electrogenic sulfide oxidation (e-SOx), may alter elemental cycling in sediments, but the nature and rates of the resulting biogeochemical transformatio...

  5. Self-assembly of biomorphic carbon/sulfur microstructures in sulfidic environments

    OpenAIRE

    Cosmidis, Julie; Templeton, Alexis S.

    2016-01-01

    In natural and laboratory-based environments experiencing sustained counter fluxes of sulfide and oxidants, elemental sulfur (S0)—a key intermediate in the sulfur cycle—can commonly accumulate. S0 is frequently invoked as a biomineralization product generated by enzymatic oxidation of hydrogen sulfide and polysulfides. Here we show the formation of S0 encapsulated in nanometre to micrometre-scale tubular and spherical organic structures that self-assemble in sulfide gradient environments in t...

  6. Silicate sulfidation and chemical differences between enstatite chondrites and Earth

    Science.gov (United States)

    Lehner, S. W.; Petaev, M. I.; Buseck, P. R.

    2013-12-01

    Isotopic similarity between the Earth-Moon system and enstatite chondrites (ECs) led to the idea that ECs were Earth's building blocks [1-3]. However, compared to Earth's mantle, ECs have low Fe0/Fe ratios, are enriched in volatile elements, and depleted in refractory lithophile elements and Mg [4]. Therefore, deriving Earth composition from ECs requires a loss of volatiles during or prior to accretion and sequestering a large fraction of Si in the deep Earth. Alternatively, the isotopic similarity between the Earth and ECs is explained by their formation from a common precursor that experienced different evolutionary paths resulting in the chemical difference [4]. The vestiges of such a precursor are still present in the unequilibrated ECs as FeO-rich silicates with O isotopic compositions identical to bulk ECs and Earth [5]. Conversion of such a precursor into the characteristic EC mineral assemblage requires high-temperature processing in an H-poor environment with high fS2 and fO2 close to that of the classic solar nebula [6], consistent with redox conditions inferred from Ti4+/Ti3+ ratios in EC pyroxene [7]. Under such conditions reaction of FeO-rich silicates with S-rich gas results in their replacement by the assemblage of FeO-poor silicates; Fe, Mg, Ca sulfides; free silica; and Si-bearing Fe,Ni metal alloy. The progressive sulfidation of ferromagnesian silicates in chondrules results in loss of Mg and addition of Fe, Mn, S, Na, K and, perhaps, other volatiles [6]. At the advanced stages of silicate sulfidation recorded in the metal-sulfide nodules [8], a portion of Si is reduced and dissolved in the Fe,Ni metal. This process is known to fractionate Si isotopes [9,10] and would explain the differences between the ECs and Earth's mantle [11]. The sulfidation of silicates also produces porous S-rich silica, a peculiar phase observed so far only in the ECs. It consists of a sinewy SiO2-rich framework enclosing numerous vesicles filled with beam

  7. Formation of Iron Sulfide in Water-Body Sediment and Its Influence on Environment

    Institute of Scientific and Technical Information of China (English)

    YAN Lei; SUMI Katsuhiro

    2008-01-01

    Iron sulfide is an important reductive pollutant in aquatic sediment, so that increasing attentions have been paid to it in recent years. In this paper, the formation of iron sulfide in water-body sediment was introduced. Moreover, its adverse influences upon environment were summarized, including direct contribution to deficiency of dissolved oxygen in water, association with eutrophication in water-bodies and impact on geochemical sulfur cycle. Since conventional chemical analysis for iron sulfide has several disadvantages, new technique for rapid determination of iron sulfide on-line was prospected.

  8. Mapping hydrogen sulfide in rats with a novel azo-based fluorescent probe.

    Science.gov (United States)

    Li, Xin; Cheng, Juan; Gong, Yanling; Yang, Bo; Hu, Yongzhou

    2015-03-15

    We report herein a reaction-based fluorescent switch-on sulfide sensor, azo3, for the quantification of endogenous sulfides in rat tissues. The sensor was exploited based on the novel azo-sulfide chemistry and designed by locking the rhodol fluorophore into its nonfluorescent form with an azo group. However, the azo group would undergo a specific and biocompatible reaction with sulfides, triggering significant fluorescence increasements which were linear to the concentrations of sulfides. Azo3 distinguished by its high sensitivity (148-fold fluorescent switch-on response), good selectivity (22-fold more selective towards sulfides than other bio-thiol species) and low detection limit (500nM). Moreover, the azo3-based assay for biological sulfides displayed the unique advantage of being insusceptible to ultraviolet (UV) irradiation. Azo3 has been successfully applied to the quantification of endogenous sulfides in rat plasma and tissues including heart, brain, liver, spleen, lung and kidney. In addition to providing azo3 as a valuable tool to analyze sulfides in biological samples, we also discussed the influences of the electron effect on the sensitivity of the probes, which would shed some light on the design of future reaction-based probes.

  9. Enhanced sulfidation xanthate flotation of malachite using ammonium ions as activator.

    Science.gov (United States)

    Wu, Dandan; Ma, Wenhui; Mao, Yingbo; Deng, Jiushuai; Wen, Shuming

    2017-05-18

    In this study, ammonium ion was used to enhance the sulfidation flotation of malachite. The effect of ammonium ion on the sulfidation flotation of malachite was investigated using microflotation test, inductively coupled plasma (ICP) analysis, zeta potential measurements, and scanning electron microscope analysis (SEM). The results of microflotation test show that the addition of sodium sulfide and ammonium sulfate resulted in better sulfidation than the addition of sodium sulfide alone. The results of ICP analysis indicate that the dissolution of enhanced sulfurized malachite surface is significantly decreased. Zeta potential measurements indicate that a smaller isoelectric point value and a large number of copper-sulfide films formed on the malachite surface by enhancing sulfidation resulted in a large amount of sodium butyl xanthate absorbed onto the enhanced sulfurized malachite surface. EDS semi-quantitative analysis and XPS analysis show that malachite was easily sulfurized by sodium sulfide with ammonium ion. These results show that the addition of ammonium ion plays a significant role in the sulfidation of malachite and results in improved flotation performance.

  10. Biological and chemical sulfide oxidation in a Beggiatoa inhabited marine sediment

    DEFF Research Database (Denmark)

    Preisler, André; de Beer, Dirk; Lichtschlag, Anna;

    2007-01-01

    gradient and corresponding high sulfide flux, a typical characteristic of Beggiatoa habitats, is not needed for their metabolic performance, but rather used as a chemotactic cue by the highly motile filaments to avoid getting lost at depth in the sediment. Indeed sulfide is a repellant for Beggiatoa...... and corresponding high sulfide flux, a typical characteristic of Beggiatoa habitats, is not needed for their metabolic performance, but rather used as a chemotactic cue by the highly motile filaments to avoid getting lost at depth in the sediment. Indeed sulfide is a repellant for Beggiatoa...

  11. Spectral induced polarization and electrodic potential monitoring of microbially mediated iron sulfide transformations

    Energy Technology Data Exchange (ETDEWEB)

    Hubbard, Susan; Personna, Y.R.; Ntarlagiannis, D.; Slater, L.; Yee, N.; O' Brien, M.; Hubbard, S.

    2008-02-15

    Stimulated sulfate-reduction is a bioremediation technique utilized for the sequestration of heavy metals in the subsurface.We performed laboratory column experiments to investigate the geoelectrical response of iron sulfide transformations by Desulfo vibriovulgaris. Two geoelectrical methods, (1) spectral induced polarization (SIP), and (2) electrodic potential measurements, were investigated. Aqueous geochemistry (sulfate, lactate, sulfide, and acetate), observations of precipitates (identified from electron microscopy as iron sulfide), and electrodic potentials on bisulfide ion (HS) sensitive silver-silver chloride (Ag-AgCl) electrodes (630 mV) were diagnostic of induced transitions between an aerobic iron sulfide forming conditions and aerobic conditions promoting iron sulfide dissolution. The SIP data showed 10m rad anomalies during iron sulfide mineralization accompanying microbial activity under an anaerobic transition. These anomalies disappeared during iron sulfide dissolution under the subsequent aerobic transition. SIP model parameters based on a Cole-Cole relaxation model of the polarization at the mineral-fluid interface were converted to (1) estimated biomineral surface area to pore volume (Sp), and (2) an equivalent polarizable sphere diameter (d) controlling the relaxation time. The temporal variation in these model parameters is consistent with filling and emptying of pores by iron sulfide biofilms, as the system transitions between anaerobic (pore filling) and aerobic (pore emptying) conditions. The results suggest that combined SIP and electrodic potential measurements might be used to monitor spatiotemporal variability in microbial iron sulfide transformations in the field.

  12. Spectral induced polarization and electrodic potential monitoring of microbially mediated iron sulfide transformations

    Science.gov (United States)

    Personna, Yves Robert; Ntarlagiannis, Dimitrios; Slater, Lee; Yee, Nathan; O'Brien, Michael; Hubbard, Susan

    2008-06-01

    Stimulated sulfate-reduction is a bioremediation technique utilized for the sequestration of heavy metals in the subsurface. We performed laboratory column experiments to investigate the geoelectrical response of iron sulfide transformations by Desulfovibrio vulgaris. Two geoelectrical methods, (1) spectral induced polarization (SIP), and (2) electrodic potential measurements, were investigated. Aqueous geochemistry (sulfate, lactate, sulfide, and acetate), observations of precipitates (identified from electron microscopy as iron sulfide), and electrodic potentials on bisulfide ion (HS-) sensitive silver-silver chloride (Ag-AgCl) electrodes (˜-630 mV) were diagnostic of induced transitions between anaerobic iron sulfide forming conditions and aerobic conditions promoting iron sulfide dissolution. The SIP data showed ˜10 mrad anomalies during iron sulfide mineralization accompanying microbial activity under an anaerobic transition. These anomalies disappeared during iron sulfide dissolution under the subsequent aerobic transition. SIP model parameters based on a Cole-Cole relaxation model of the polarization at the mineral-fluid interface were converted to (1) estimated biomineral surface area to pore volume (Sp), and (2) an equivalent polarizable sphere diameter (d) controlling the relaxation time. The temporal variation in these model parameters is consistent with filling and emptying of pores by iron sulfide biofilms, as the system transitions between anaerobic (pore filling) and aerobic (pore emptying) conditions. The results suggest that combined SIP and electrodic potential measurements might be used to monitor spatiotemporal variability in microbial iron sulfide transformations in the field.

  13. Microbial oxidation of soluble sulfide in produced water from the Bakkeen Sands

    Energy Technology Data Exchange (ETDEWEB)

    Gevertz, D.; Zimmerman, S. [Agouron Institute, La Jolla, CA (United States); Jenneman, G.E. [Phillips Petroleum Company, Bartlesville, OK (United States)] [and others

    1995-12-31

    The presence of soluble sulfide in produced water results in problems for the petroleum industry due to its toxicity, odor, corrosive nature, and potential for wellbore plugging. Sulfide oxidation by indigenous nitrate-reducing bacteria (NRB) present in brine collected from wells at the Coleville Unit (CVU) in Saskatchewan, Canada, was investigated. Sulfide oxidation took place readily when nitrate and phosphate were added to brine enrichment cultures, resulting in a decrease in sulfide levels of 99-165 ppm to nondetectable levels (< 3.3 ppm). Produced water collected from a number of producing wells was screened to determine the time required for complete sulfide oxidation, in order to select candidate wells for treatment. Three wells were chosen, based on sulfide removal in 48 hours or less. These wells were treated down the backside of the annulus with a solution containing 10 mM KNO{sub 3} and 100 {mu}M NaH{sub 2}PO{sub 4}. Following a 24- to 72-hour shut-in, reductions in pretreatment sulfide levels of greater than 90% were observed for two of the wells, as well as sustained sulfide reductions of 50% for at least two days following startup. NRB populations in the produced brine were observed to increase significantly following treatment, but no significant increases in sulfate-reducing bacteria were observed. These results demonstrate the technical feasibility of stimulating indigenous populations of NRB to remediate and control sulfide in produced brine.

  14. Sulfides in diamonds and in xenoliths from kimberlite pipes of Yakutiia

    Science.gov (United States)

    Bulanova, Galina P.; Spetsius, Zdislav V.; Leskova, Nelli V.

    The characteristics of sulfides from diamonds and xenoliths are compared using literature data on the mineralogy of sulfides in diamonds and in deep-seated xenoliths from kimberlite pipes. Results are presented on the Fe-Ni-Cu-Co-S mineral systems of mantle associations, sulfide inclusions in diamonds and megacrystals of kimberlite rocks, and minerals of the Fe-Ni-Cu-Co-S system in mantle xenoliths from kimberlite pipes. Particular consideration is given to the nature of sulfide mineralization in mantle xenoliths and diamonds.

  15. Use of hydrochloric acid for determinining solid-phase arsenic partitioning in sulfidic sediments.

    Science.gov (United States)

    Wilkin, Richard T; Ford, Robert G

    2002-11-15

    We examined the use of room-temperature hydrochloric acid (1-6 M) and salt solutions of magnesium chloride, sodium carbonate, and sodium sulfide for the removal of arsenic from synthetic iron monosulfides and contaminated sediments containing acid-volatile sulfides (AVS). Results indicate that acid-soluble arsenic reacts with H2S released from AVS phases and precipitates at low pH as disordered orpiment or alacranite. Arsenic sulfide precipitation is consistent with geochemical modeling in that conditions during acid extraction are predicted to be oversaturated with respect to orpiment, realgar, or both. Binding of arsenic with sulfide at low pH is sufficiently strong that 6 M HCl will not keep spiked arsenic in the dissolved fraction. Over a wide range of AVS concentrations and molar [As]/[AVS] ratios, acid extraction of arsenic from sulfide-bearing sediments will give biased results that overestimate the stability or underestimate the bioavailability of sediment-bound arsenic. Alkaline solutions of sodium sulfide and sodium carbonate are efficient in removing arsenic from arsenic sulfides and mixed iron-arsenic sulfides because of the high solubility of arsenic at alkaline pH, the formation of stable arsenic complexes with sulfide or carbonate, or both.

  16. Spontaneous electrochemical treatment for sulfur recovery by a sulfide oxidation/vanadium(V) reduction galvanic cell.

    Science.gov (United States)

    Kijjanapanich, Pimluck; Kijjanapanich, Pairoje; Annachhatre, Ajit P; Esposito, Giovanni; Lens, Piet N L

    2015-02-01

    Sulfide is the product of the biological sulfate reduction process which gives toxicity and odor problems. Wastewaters or bioreactor effluents containing sulfide can cause severe environmental impacts. Electrochemical treatment can be an alternative approach for sulfide removal and sulfur recovery from such sulfide rich solutions. This study aims to develop a spontaneous electrochemical sulfide oxidation/vanadium(V) reduction cell with a graphite electrode system to recover sulfide as elemental sulfur. The effects of the internal and external resistance on the sulfide removal efficiency and electrical current produced were investigated at different pH. A high surface area of the graphite electrode is required in order to have as less internal resistance as possible. In this study, graphite powder was added (contact area >633 cm(2)) in order to reduce the internal resistance. A sulfide removal efficiency up to 91% and electrical charge of more than 400 C were achieved when using five graphite rods supplemented with graphite powder as the electrode at an external resistance of 30 Ω and a sulfide concentration of 250 mg L(-1). Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Sulfur speciation and sulfide oxidation in the water column of the Black Sea

    Science.gov (United States)

    Luther, George W., III; Church, Thomas M.; Powell, David

    We have applied sulfur speciation techniques to understand the chemistry and cycling of sulfur in Black Sea waters. The only reduced dissolved inorganic sulfur species detected (above the low minimum detection limits of the voltammetric methods employed) in the water column was hydrogen sulfide. The maximum concentration of sulfide (423 μM) is similar to previous reports. Using a cathodic stripping square wave voltammetry (CSSWV) method for nanomolar levels of sulfide, we determined the precise boundary between the "free" hydrogen sulfide (sulfidic) zone and the upper (oxic/suboxic) water column at the two stations studied. This boundary has apparently moved up by about 50 m in the past 20 years. Our results help demonstrate three chemically distinct zones of water in the central basin of the Black Sea: (1) the oxic [0-65 m], (2) the anoxic/nonsulfidic [65-100 m] and (3) the sulfidic [>100 m]. Sulfide bound to metals ("complexed" sulfide) is observed in both the oxic and anoxic/nonsulfidic zones of the water column. This supports previous studies on metal sulfide forms. From the electrochemical data, it is possible to estimate the strength of the complexation of sulfide to metals (log K = 10 to 11). Thiosulfate and sulfite were below our minimum detectable limit (MDL) of 50 nM using CSSWV. Elemental sulfur (MDL 5 nM) was detected below the onset of the hydrogen sulfide zone (90-100 m) with a maximum of 30-60 nM near 120 m. The sulfur speciation results for the Black Sea are lower by one order of magnitude or more than other marine systems such as the Cariaco Trench and salt marshes. New HPLC techniques were applied to detect thiols at submicromolar levels. The presence of thiols (2-mercaptoethylamine, 2-mercaptoethanol, N-acetylcysteine and glutathione) is correlated with the remineralization of organic matter at the oxic and anoxic/nonsulfidic interface. Water samples collected from the upper 50 m of the sulfidic zone showed significant sulfide oxidation on

  18. Corrosion of concrete sewers--the kinetics of hydrogen sulfide oxidation.

    Science.gov (United States)

    Vollertsen, Jes; Nielsen, Asbjørn Haaning; Jensen, Henriette Stokbro; Wium-Andersen, Tove; Hvitved-Jacobsen, Thorkild

    2008-05-01

    Hydrogen sulfide absorption and oxidation by corroding concrete surfaces was quantified in a test rig consisting of 6 concrete pipes operated under sewer conditions. The test rig was placed in an underground sewer monitoring station with access to fresh wastewater. Hydrogen sulfide gas was injected into the pipe every 2nd hour to peak concentrations around 1000 ppm. After some months of operation, the hydrogen sulfide became rapidly oxidized by the corroding concrete surfaces. At hydrogen sulfide concentrations of 1000 ppm, oxidation rates as high as 1 mg S m(-2) s(-1) were observed. The oxidation process followed simple nth order kinetics with a process order of 0.45-0.75. Extrapolating the results to gravity sewer systems showed that hydrogen sulfide oxidation by corroding concrete is a fast process compared to the release of hydrogen sulfide from the bulk water, resulting in low gas concentrations compared with equilibrium. Balancing hydrogen sulfide release with hydrogen sulfide oxidation at steady state conditions demonstrated that significant corrosion rates--several millimeters of concrete per year--can potentially occur at hydrogen sulfide gas phase concentrations well below 5-10 ppm. The results obtained in the study advances the knowledge on prediction of sewer concrete corrosion and the extent of odor problems.

  19. Phototrophic sulfide oxidation: environmental insights and a method for kinetic analysis

    Directory of Open Access Journals (Sweden)

    Thomas E Hanson

    2013-12-01

    Full Text Available Previously, we presented data that indicated microbial sulfide oxidation would out-compete strictly chemical, abiotic sulfide oxidation reactions under nearly all conditions relevant to extant ecosystems (Luther et al., 2011. In particular, we showed how anaerobic microbial sulfide oxidation rates were several orders of magnitude higher than even metal catalyzed aerobic sulfide oxidation processes. The fact that biotic anaerobic sulfide oxidation is kinetically superior to abiotic reactions implies that nearly all anaerobic and sulfidic environments should host microbial populations that oxidize sulfide at appreciable rates. This was likely an important biogeochemical process during long stretches of euxinia in the oceans suggested by the geologic record. In particular, phototrophic sulfide oxidation allows the utilization of carbon dioxide as the electron acceptor suggesting that this process should be particularly widespread rather than relying on the presence of other chemical oxidants. Using the Chesapeake Bay as an example, we argue that phototrophic sulfide oxidation may be more important in many environments than is currently appreciated. Finally, we present methodological considerations to assist other groups that wish to study this process.

  20. Identification, characterization and application of sulfide-oxidizing bacteria in oil fields

    Energy Technology Data Exchange (ETDEWEB)

    Jenneman, G.E. [Phillips Petroleum Co., Bartlesville, OK (United States). Research and Development Dept; Gevertz, D. [Agouron Institute, La Jolla, CA (United States)

    2000-07-01

    The efforts being made to identify and characterize sulfide-oxidizing bacteria (SOB) in oil fields were described. The role of SOB in the cycling of sulfur in shallow oil reservoirs in Western Canada and Western Texas was also explained. Field tests from reservoirs where anaerobic sulfide oxidation can be potentially applied were also included in this presentation. Sulfides are not desirable in oil fields because they are toxic, corrosive and form insoluble metal sulfides. Nitrate has been found to stimulate the activity of indigenous, anaerobic SOB when amended to sulfide-laden sewage sludges and pond sediments. In this study sulfide-laden, produced brine was collected from a field and dispensed into sterile, anaerobic bottles and amended with potassium nitrate and sodium phosphate. Oxidation of the sulfide was monitored using colour as a means by which to detect oxidation. Results showed that sulfide-oxidizing activity in brines from the Coleville field in Western Canada is a result of autotrophic SOB. Sulfide-oxidizing activity in produced brines collected from Western Texas oil fields needed the addition of organic acids and yeast extract, suggesting oxidation by heterotrophic SOB.19 refs., 1 tab., 1 fig.

  1. Pd-NHC-Catalyzed Alkynylation of General Aryl Sulfides with Alkynyl Grignard Reagents.

    Science.gov (United States)

    Baralle, Alexandre; Yorimitsu, Hideki; Osuka, Atsuhiro

    2016-07-25

    Cross-coupling reactions of unactivated aryl sulfides with alkynylmagnesium chloride have been invented to afford 1-aryl-1-alkynes with the aid of a palladium/N-heterocyclic carbene complex. This reaction has by far the widest scope of all transformations utilizing aryl sulfides and alkynes, while known cross-coupling alkynylations of aryl-sulfur electrophiles require activated azaaryl sulfides, thiolactams, or arenesulfonyl chlorides. The alkynylation of aryl sulfides is compatible with typical protecting functional groups. The alkynylation is applied to the synthesis of benzofuran-based fluorescent molecules by taking advantage of characteristic organosulfur chemistry.

  2. XAFS characterization of industrial catalysts: in situ study of phase transformation of nickel sulfide

    Science.gov (United States)

    Wang, J.; Jia, Z.; Wang, Q.; Zhao, S.; Xu, Z.; Yang, W.; Frenkel, A. I.

    2016-05-01

    The online sulfiding process for nickel-contained catalyst often ends up with a nickel sulfide mixture in refinery plant. To elucidate the local environment of nickel and its corresponding sulfur species, a model catalyst (nickel sulfide) and model thermal process were employed to explore the possibilities for characterization of real catalysts in industrial conditions. The present investigation shows effectiveness of in situ XANES and EXAFS measurements for studying the phase stability and phase composition in these systems, which could be used to simulate real sulfiding process in industrial reactions, such as hydrodesulfurizations of oil.

  3. Vesicle-metal-sulfide assemblages from the Chelyabinsk meteorite

    Science.gov (United States)

    Andronikov, A.; Lauretta, D.; Hill, D.; Andronikova, I.

    2014-07-01

    On February 15, 2013, an ET object entered the Earth's atmosphere over the Russian city of Chelyabinsk. It entered at a preatmospheric velocity of 18.6 km/sec at the angle of 17--20°. The bolide responsible for this event was estimated to be 17-20 m in diameter and had a mass of ˜10 Ktons; the ensuing airburst occurred at an altitude >20 km and released a total energy of ˜440 kT [1,2]. The Chelyabinsk meteorite is an equilibrated LL5 ordinary chondrite, shock stage S4, and weathering grade WG0 similar to other LL5 falls [1,2]. Our studied sample is an impact melt breccia consisting of shock-darkened chondrite clasts (SDC) and vesicular impact melt lithology (IML). The SDC have recrystallized textures and contain barred- and porphyritic-olivine, porphyritic-olivine-pyroxene and radial-pyroxene chondrules in the intrachondrule matrix. A dense network of thin fractures in the SDC is filled up with opaque minerals [cf. 3]. Metals in the SDC are kamacite (4.7--8.5 % Ni), taenite (21.4--33.5 % Ni), and martensite (14.5--18.6 % Ni). The IML consists mostly of tiny (bearing troilite (62.2--64.2 % Fe; 35.2--37.2 % S; 3000--5000 ppm Ni), with rare pentlandite (41.2--48.6 % Fe, 33.2--34.3 % S, 19.4--23.9 % Ni). The presence of abundant vesicles in the IML indicates strong heating and volatilization. Since no other phase except for sulfide-metal assemblages were observed to fill up vesicles, the likely source of volatiles is S vapor formed by vaporization of FeS during impact melting [cf. 4]. Molten metal and sulfide coalesced into droplets of metal-sulfide liquids forming eventually sulfide-metal assemblages. A notable compositional difference is observed between sulfides not containing metals and those with metals. The metal-free sulfides display higher concentrations of such elements as Ni, Co, Ga, Ge, As, Mo, Ru, Pd, Sn, Sb, Te, Au, and Hg, and lower amounts of Cu than their metal-bearing counterparts. The metal-free sulfides may represent loci of former ''parental'' Fe

  4. In Situ Gene Expression Responsible for Sulfide Oxidation and CO2 Fixation of an Uncultured Large Sausage-Shaped Aquificae Bacterium in a Sulfidic Hot Spring.

    Science.gov (United States)

    Tamazawa, Satoshi; Yamamoto, Kyosuke; Takasaki, Kazuto; Mitani, Yasuo; Hanada, Satoshi; Kamagata, Yoichi; Tamaki, Hideyuki

    2016-06-25

    We investigated the in situ gene expression profile of sulfur-turf microbial mats dominated by an uncultured large sausage-shaped Aquificae bacterium, a key metabolic player in sulfur-turfs in sulfidic hot springs. A reverse transcription-PCR analysis revealed that the genes responsible for sulfide, sulfite, and thiosulfate oxidation and carbon fixation via the reductive TCA cycle were continuously expressed in sulfur-turf mats taken at different sampling points, seasons, and years. These results suggest that the uncultured large sausage-shaped bacterium has the ability to grow chemolithoautotrophically and plays key roles as a primary producer in the sulfidic hot spring ecosystem in situ.

  5. Multi-dimensional modeling of atmospheric copper-sulfidation corrosion on non-planar substrates.

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Ken Shuang

    2004-11-01

    This report documents the author's efforts in the deterministic modeling of copper-sulfidation corrosion on non-planar substrates such as diodes and electrical connectors. A new framework based on Goma was developed for multi-dimensional modeling of atmospheric copper-sulfidation corrosion on non-planar substrates. In this framework, the moving sulfidation front is explicitly tracked by treating the finite-element mesh as a pseudo solid with an arbitrary Lagrangian-Eulerian formulation and repeatedly performing re-meshing using CUBIT and re-mapping using MAPVAR. Three one-dimensional studies were performed for verifying the framework in asymptotic regimes. Limited model validation was also carried out by comparing computed copper-sulfide thickness with experimental data. The framework was first demonstrated in modeling one-dimensional copper sulfidation with charge separation. It was found that both the thickness of the space-charge layers and the electrical potential at the sulfidation surface decrease rapidly as the Cu{sub 2}S layer thickens initially but eventually reach equilibrium values as Cu{sub 2}S layer becomes sufficiently thick; it was also found that electroneutrality is a reasonable approximation and that the electro-migration flux may be estimated by using the equilibrium potential difference between the sulfidation and annihilation surfaces when the Cu{sub 2}S layer is sufficiently thick. The framework was then employed to model copper sulfidation in the solid-state-diffusion controlled regime (i.e. stage II sulfidation) on a prototypical diode until a continuous Cu{sub 2}S film was formed on the diode surface. The framework was also applied to model copper sulfidation on an intermittent electrical contact between a gold-plated copper pin and gold-plated copper pad; the presence of Cu{sub 2}S was found to raise the effective electrical resistance drastically. Lastly, future research needs in modeling atmospheric copper sulfidation are discussed.

  6. 舒林酸对丙戊酸孤独症动物模型大鼠氧化应激变化的影响%Effects of sulindac on oxidative stress in an autistic model induced by pre-natal exposure to valproic acid

    Institute of Scientific and Technical Information of China (English)

    张应花; 杨彩玲; 崔卫刚; 王中平; 小军; 李瑞锡

    2014-01-01

    [ ABSTRACT] AIM:To investigate the effects of sulindac on oxidative stress in autism.METHODS:With an au-tistic model induced by prenatal exposure to valproic acid ( VPA) , we detected the expression of the signaling molecules of canonical Wnt pathway in the prefrontal cortex ( PFC) and hippocampus ( HC) of autistic rats treated with sulindac.The protein expression levels of glycogen synthase kinase 3β(GSK-3β), β-catenin and 4-hydroxynonenal (4-HNE) were ob-served by Western blotting.The mRNA expression of thioredoxin(Trx)1 and Trx2 was assessed by semi-quantitative RT-PCR.RESULTS:The protein level of GSK-3βand mRNA levels of Trx1 and Trx2 were lower, whereas the protein expres-sion levels ofβ-catenin and 4-HNE were higher in VPA group than those in control group.In contrast, the protein levels of GSK-3βwere significantly higher in the animals treated with both VPA and sulindac than those in VPA group, while the lev-els ofβ-catenin and 4-HNE were decreased.CONCLUSION:Sulindac attenuates oxidative stress in the pathogenesis of au-tism, suggesting the up-regulation of the Wnt/β-catenin signaling pathway disrupts oxidative homeostasis and further facili-tates susceptibility to autism.%目的:探讨舒林酸对孤独症发生过程中氧化应激变化的影响。方法:利用丙戊酸( VPA)孤独症动物模型,检测经典Wnt信号通路特异性抑制剂舒林酸处理后经典Wnt信号通路及氧化应激标志物在孤独症模型大鼠前额叶皮质及海马脑区的表达变化。 Western blotting法检测糖原合成激酶3β( GSK-3β)、β-catenin和4-羟基壬烯醛(4-HNE)表达,半定量RT-PCR法检测硫氧还蛋白(Trx)1和Trx2 mRNA表达。结果:与对照组相比,在前额叶皮质及海马脑区VPA组GSK-3β蛋白表达减少, Trx1和Trx mRNA 表达减少,β-catenin与4-HNE的表达增加;而与VPA组相比,VPA与舒林酸同时处理组GSK-3β的表达显著增加,β-catenin和4-HNE的表达显著减少

  7. Surface-treatment of Alkaline Earth Sulfides Based Phosphor

    Institute of Scientific and Technical Information of China (English)

    GUO Chong-feng; CHU Ben-li; XU Jian; SU Qiang

    2004-01-01

    A series of alkaline earth sulfides based phosphors Ca0.8Sr0.2S∶Eu2+, Tm3+ were covered with a layer of protective coating with alkaline earth fluorides by heating the mixture of phosphor and NH4HF2 at elevated temperatures. The coatings were characterized by means of XRD and SEM. The optical properties of the coated phosphors and the influences of the coating on their properties have been discussed extensively. The stabilities of the coated and uncoated phosphors have been compared.

  8. Formation of Submicron Copper Sulfide Particles Using Spray Pyrolysis Method

    Science.gov (United States)

    Lenggoro, I.; Kang, Yun; Komiya, Takafumi; Okuyama, Kikuo; Tohge, Noboru

    1998-03-01

    The morphology and crystalline phase of submicron copper sulfide particles prepared by spray pyrolysis method have been studied. In a nitrogen gas atmosphere, the covellite phase (CuS) spherical particles could be prepared using the solution with molar ratio of copper nitrate to thiourea and furnace temperatures of 1:2 at 200 300°C, as well as of 1:5 at 200 600°C. The crystalline phase of particles was highly depended on the composition of the precursors and the pyrolysis temperature. The sphericity of particles could be enhanced by increasing the temperature and prolonging the residence time of the droplets or particles in the furnace.

  9. Therapeutic application of hydrogen sulfide donors: the potential and challenges.

    Science.gov (United States)

    Wu, Dan; Hu, Qingxun; Zhu, Yizhun

    2016-03-01

    Hydrogen sulfide (H2S), a colorless gas smelling of rotten egg, has long been considered a toxic gas and environment hazard. However, evidences show that H2S plays a great role in many physiological and pathological activities, and it exhibits different effects when applied at various doses. In this review, we summarize the chemistry and biomedical applications of H2S-releasing compounds, including inorganic salts, phosphorodithioate derivatives, derivatives of Allium sativum extracts, derivatives of thioaminoacids, and derivatives of antiinflammatory drugs.

  10. Handbook of Phase Transition Sulfides, Selenides and Tellurides,

    Science.gov (United States)

    1984-07-01

    made (as reported in Ref. 5) in 61899 by Mourlot. More recent studies showed that he actually prepared CrSo.9 7 and that pure CrS should have a density ...1n2S 3 Indium Sulfide or Di-Indium Trisulflde In2S3 exists as cubic a-In 2S3 and tetragonal 0-In 2S3. Until recently, no detailed studies on the...Mn+2 is bonded tetrahedrally through sulfur atoms to its nearest Mn neighbors. The crystal lattice parameters have been studied as a function of 0

  11. Sulfide Formation And Its Impacts On A Developing Country

    DEFF Research Database (Denmark)

    Matias, Natércia; Mutuvúie, Raúl; Vollertsen, Jes

    2014-01-01

    consumption, such as Mozambique, these changes are particularly important due to the potential increase of sulphide formation and the consequent release of hydrogen sulphide and other malodorous or toxic gases to the atmosphere. A major expansion of the sewer systems in the main cities of Mozambique...... is expected in the near future, with the associated longer wastewater travel times and increasing problems of septicity and hydrogen sulfide gas impacts. In order to better understand the in-sewer processes under local conditions, evaluate risks and exemplify how to support general drainage systems planning...

  12. Is Lithium Sulfide a MgB2-like Superconductor?

    OpenAIRE

    Isikaku-Ironkwe, O. P.

    2012-01-01

    Lithium Sulfide, Li2S, is an anti-fluorite semiconductor with a band-gap of 3.865 eV. It also has exactly the same valence electron count, Ne, and atomic number, Z, as magnesium diboride, MgB2. Both have almost the same formula weight. This qualifies Li2S as a magnesium-diboride like material. Li2S passes the same computational material specific test for superconductivity as MgB2. Using our recently developed symmetry rules for searching for superconductors, we predict that Li2S, with electro...

  13. Isolation and characterization of deodorizing bacteria for organic sulfide malodor

    Institute of Scientific and Technical Information of China (English)

    JIANG An-xi; LIU Bo; ZHAO Yang-guo; LI Zheng; BAI Yu; CHENG Yang-xue

    2004-01-01

    Strain Jll screened out from different odor origins can efficiently degrade methyl mercaptan and ethanethiol whereas has no ability to remove dimethyl sulfide. The results indicated that the strain Jll breaks only the C-SH bond. The optimum temperature and pH of Jll are 20-30℃ and 6.0-8.3 respectively. A systematic identification method-16S rDNA gene sequence comparison, for deodorizing bacteria was carried out. The 16S rDNA gene sequence analysis of strain Jll showed the highest level of 97% homology to Rape rhizosphere.

  14. Analytical Measurement of Discrete Hydrogen Sulfide Pools in Biological Specimens

    OpenAIRE

    Shen, Xinggui; Peter, Elvis A.; Bir, Shyamal; Wang, Rui; Kevil, Christopher G.

    2012-01-01

    Hydrogen sulfide (H2S) is a ubiquitous gaseous signaling molecule that plays a vital role in numerous cellular functions and has become the focus of many research endeavors including pharmaco-therapeutic manipulation. Amongst the challenges facing the field is the accurate measurement of biologically active H2S. We have recently reported that the typically used methylene blue method and its associated results are invalid and do not measure bonafide H2S. The complexity of analytical H2S measur...

  15. Microbial Oxidation of Iron Sulfides in Anaerobic Environments

    DEFF Research Database (Denmark)

    Vaclavkova, Sarka

    processes in natural anoxic soils is supported by the fact that about 17 % of drinking water wells in Denmark were lately found to be contaminated by NO3- in concentrations exceeding the allowed limit of 50 mgL-1. This study experimentally documented potential for MISON in a range of anoxic aquatic......Abstract (shortened): Iron sulfides (FeSx), representing 0.04-10 % of Danish dry soil weight, oxidize in a presence of oxygen, releasing sulfuric acid and free iron. Environmental impact of FeSx oxidation is commonly seen on agricultural sites cultivated by drainage as acid sulfate soil formation...

  16. Spectroscopy of titanium-doped gallium lanthanum sulfide glass

    OpenAIRE

    2008-01-01

    Titanium-doped gallium lanthanum sulfide (Ti:GLS) and gallium lanthanum oxysulfide (Ti:GLSO) glasses have an absorption band at similar to 500-600 nm that cannot be fully resolved because of its proximity to the band edge of the glass. At concentrations >0.5% a shoulder at 980 nm is observed in Ti:GLS but not in Ti :GLSO. The emission spectra of Ti:GLS and T :GLSO both peak at 900 nm with lifetimes of 67 and 97)us, respectively. We propose that the absorption at similar to 600 nm is due to th...

  17. New Findings in Hydrogen Sulfide Related Corrosion of Concrete Sewers

    DEFF Research Database (Denmark)

    Nielsen, Asbjørn Haaning; Jensen, Henriette Stokbro; Hvitved-Jacobsen, Thorkild

    2009-01-01

    This paper summarizes major findings of a long-term study of hydrogen sulfide gas (H2S) adsorption and oxidation on concrete and plastic sewer pipe surfaces. The processes have been studied using a pilot-scale setup designed to replicate conditions in a gravity sewer located downstream of a force...... H2S concentration in concrete sewers would typically amount to a few percent of the equilibrium concentration calculated from Henrys law. In plastic pipe sewers, significantly higher concentrations were predicted because of the slower adsorption and oxidation kinetics on these surfaces. Finally...

  18. Oxidation sulfidation resistance of Fe-Cr-Ni alloys

    Energy Technology Data Exchange (ETDEWEB)

    Natesan, Ken (Naperville, IL); Baxter, David J. (Woodridge, IL)

    1984-01-01

    High temperature resistance of Fe-Cr-Ni alloy compositions to oxidative and/or sulfidative conditions is provided by the incorporation of about 1-8 wt. % of Zr or Nb and results in a two-phase composition having an alloy matrix as the first phase and a fine grained intermetallic composition as the second phase. The presence and location of the intermetallic composition between grains of the matrix provides mechanical strength, enhanced surface scale adhesion, and resistance to corrosive attack between grains of the alloy matrix at temperatures of 500.degree.-1000.degree. C.

  19. Facile aqueous-phase synthesis of copper sulfide nanofibers

    Science.gov (United States)

    Tang, Zengmin; Im, Sang Hyuk; Kim, Woo-Sik; Yu, Taekyung

    2017-07-01

    We report a facile aqueous-phase synthetic route to vine-like copper sulfide (CuS) nanofibers prepared by reacting elemental sulfur with Cu+-branched polyethyleneimine (BPEI) complex obtained by the reaction of Cu2+ with ascorbic acid in the presence of BPEI. By controlling the concentration of BPEI, we could easily control the morphology of CuS from nanofibers to hollow nanoparticles. We also found that concentration of BPEI and the presence of halide anion would play important roles in the formation of vine-like CuS nanofibers.

  20. Synthesis of Lead Sulfide Nanoparticles by Chemical Precipitation Method

    Science.gov (United States)

    Chongad, L. S.; Sharma, A.; Banerjee, M.; Jain, A.

    2016-10-01

    Lead sulfide (PbS) nanoparticles were prepared by chemical precipitation method (CPM) with the assistance of H2S gas. The microstructure and morphology of the synthesized nanoparticles have been investigated using X-ray diffraction (XRD) and transmission electron microscopy (TEM). The XRD patterns of the PbS nanoparticles reveal formation of cubic phase. To investigate the quality of prepared nanoparticles, the particles size, lattice constant, strain, dislocation density etc. have been determined using XRD. TEM images reveal formation of cubic nanoparticles and the particle size determined from TEM images agree well with those from XRD.

  1. Chemical Vapor Deposited Zinc Sulfide. SPIE Press Monograph

    Energy Technology Data Exchange (ETDEWEB)

    McCloy, John S.; Tustison, Randal W.

    2013-04-22

    Zinc sulfide has shown unequaled utility for infrared windows that require a combination of long-wavelength infrared transparency, mechanical durability, and elevated-temperature performance. This book reviews the physical properties of chemical vapor deposited ZnS and their relationship to the CVD process that produced them. An in-depth look at the material microstructure is included, along with a discussion of the material's optical properties. Finally, because the CVD process itself is central to the development of this material, a brief history is presented.

  2. Zinc sulfide in intestinal cell granules of Ancylostoma caninum adults

    Energy Technology Data Exchange (ETDEWEB)

    Gianotti, A.J.; Clark, D.T.; Dash, J. (Portland State Univ., OR (USA))

    1991-04-01

    A source of confusion has existed since the turn of the century about the reddish brown, weakly birefringent 'sphaerocrystals' located in the intestines of strongyle nematodes, Strongylus and Ancylostoma. X-ray diffraction and energy dispersive spectrometric analyses were used for accurate determination of the crystalline order and elemental composition of the granules in the canine hookworm Ancylostoma caninum. The composition of the intestinal pigmented granules was identified unequivocally as zinc sulfide. It seems most probable that the granules serve to detoxify high levels of metallic ions (specifically zinc) present due to the large intake of host blood.

  3. Effect of mineral processing wastewater on flotation of sulfide minerals

    Institute of Scientific and Technical Information of China (English)

    CHEN Jian-ming; LIU Run-qing; SUN Wei; QIU Guan-zhou

    2009-01-01

    The effects of mineral processing wastewater on sulfide minerals were investigated by flotation, infrared spectrometry and electrochemistry test. The results show that lead-concentrate water can improve the flotation of galena, while the sulfur-concentrate water has negative effect on flotation of galena compared with distilled water. The flotation behavior of pyrite is contrary to that of galena in three kinds of water. Infrared spectra indicate that the residual collector in the lead-concentrate water is beneficial to the formation of lead xanthate on the surface of galena. Electrochemistry results indicate that electrochemistry reaction on galena surface has apparent change. The anode polarization is improved and cathode polarization is depressed.

  4. Dynamic corrosion of copper-nickel sulfide by Acidithiobacillus ferrooxidans

    Institute of Scientific and Technical Information of China (English)

    TONG Lin-lin; JIANG Mao-fa; YANG Hong-ying; YU Juan; FAN You-jing; ZHANG Yao

    2009-01-01

    The dynamic corrosion process of bio-oxidation of copper-nickel sulfide from Karatungk in northern Xinjiang Province of China was studied. The polished wafer of the copper-nickel sulphide was used to carry on a series of oxidation corrosion experiment by Acidithiobacillus ferrooxidans. The changes of superficial corrosion appearance and the mineral dynamic corrosion process were discovered by microscope observation. Then, the galvanic cell model was established, and the bio-oxidation activation order of typical copper-nickel sulphide minerals was ascertained as pyrrhotite>pentlandite>chalocopyrite.

  5. Effect of Methanethiol on Product Formation in a Biological Sulfide Oxidition process at Natron-alkaline Conditions

    NARCIS (Netherlands)

    Bosch, van den P.L.F.; Fortuny-Picornell, M.; Janssen, A.J.H.

    2009-01-01

    The effects of methanethiol (MT) on biological sulfide oxidation were studied in a continuously operated bioreactor, in which chemolithoautotrophic bacteria belonging to the genus Thioalkalivibrio convert hydrogen sulfide (H2S) at natron-alkaline conditions. Previous bioreactor experiments have

  6. Pyritization processes and greigite formation in the advancing sulfidization front in the Upper Pleistocene sediments of the Black Sea

    DEFF Research Database (Denmark)

    Neretin, LN; Bottcher, ME; Jørgensen, BB

    2004-01-01

    Pyritization in late Pleistocene sediments of the Black Sea is driven by sulfide formed during anaerobic methane oxidation. A sulfidization front is formed by the opposing gradients of sulfide and dissolved iron. The sulfidization processes are controlled by the diffusion flux of sulfide from above...... and by the solid reactive iron content. Two processes of diffusion-limited pyrite formation were identified. The first process includes pyrite precipitation with the accumulation of iron sulfide precursors with the average chemical composition of FeSn (n = 1.10-1.29), including greigite. Elemental sulfur...... and polysulfides, formed from H,S by a reductive dissolution of Fe(Ill)-containing minerals, serve as intermediates to convert iron sulfides into pyrite. In the second process, a "direct" pyrite precipitation occurs through prolonged exposure of iron-containing minerals to dissolved sulfide. Methane-driven sulfate...

  7. Artificial Corrosion of Cu-Alloys. A Contribution to Understanding Microbial and Nonmicrobial Sulfide Corrosion.

    Science.gov (United States)

    1992-01-01

    therefore, the dominant reduced sulfur species considered in this paper. Conditions of Mineral Formation Figures 14 and 15 show the stability fields...would have been reduced to < 2 ppm in the first week. Although such low sulfide levels are not conducive to Cu-S mineral formation , copper sulfide

  8. The sampling of hydrogen sulfide in air with impregnated filter paper

    NARCIS (Netherlands)

    Huygen, C.

    1964-01-01

    A method is proposed for the quantitative collection of hydrogen sulfide in air on impregnated filter paper. An aqueous solution of potassium hydroxide, potassium zincate and glycerol is used as impregnating fluid. The stability of the collected sulfide and the efficiency of collection at different

  9. The Determination of Hydrogen Sulfide in Stack Gases, Iodometric Titration After Sulfite Removal.

    Science.gov (United States)

    Robles, E. G.

    The determination of hydrogen sulfide in effluents from coal-fired furnaces and incinerators is complicated by the presence of sulfur oxides (which form acids). Organic compounds also may interfere with or prevent the formation of the cadmium sulfide precipitate or give false positive results because of reaction with iodine. The report presents a…

  10. Description of a redox-controlled sulfidostat for the growth of sulfide-oxidizing phototrophs

    NARCIS (Netherlands)

    Sanchez, O; vanGemerden, H; Mas, J

    1996-01-01

    This paper describes a novel type of continuous culture for the growth of phototrophic sulfur oxidizers under constant concentrations of hydrogen sulfide, The culture maintains a constant concentration of sulfide despite possible variations in external factors likely to affect photosynthetic activit

  11. Effect of sulfide pollution on the stability of the protective film of benzotriazole on copper

    Energy Technology Data Exchange (ETDEWEB)

    Al Kharafi, F.M. [Chemistry Department, Faculty of Science, Kuwait University (Kuwait)], E-mail: fayzah@aas.com.kw; Abdullah, A.M.; Ghayad, I.M. [Chemistry Department, Faculty of Science, Kuwait University (Kuwait); Ateya, B.G. [Chemistry Department, Faculty of Science, Kuwait University (Kuwait)], E-mail: bgateya@yahoo.com

    2007-09-15

    Benzotriazole (BTAH) is an excellent inhibitor for the corrosion of copper and many of its alloys in unpolluted media. Protection is attributed to the formation of a film of Cu(I)BTA. Injection of sulfide ions into a benzotriazole inhibited salt water damages the protective Cu(I)BTA film very rapidly, increases the corrosion rate and leads to the formation of copper sulfide. This effect is quite marked at a sulfide concentration as low as 10{sup -5} M (about 0.3 ppm sulfur) in the presence of 10{sup -2} M BTAH, which is 1000-fold greater than that of the sulfide ion. The intensity of sulfide attack increases with its concentration. Prolonged pre-passivation of copper in the BTAH protected medium even at high concentration does not markedly improve the resistance of the protective film to sulfide attack. This finding is contrary to a well-documented phenomenon in unpolluted media where the inhibiting efficiency of BTAH increases with the time of immersion and the concentration of the inhibitor. X-ray photoelectron spectroscopy (XPS) reveals the presence of both sulfide and BTAH on the corroded surface indicating that sulfide attack is localized.

  12. Lanthanide complexes as luminogenic probes to measure sulfide levels in industrial samples

    Energy Technology Data Exchange (ETDEWEB)

    Thorson, Megan K. [Department of Medicinal Chemistry, University of Utah College of Pharmacy, Salt Lake City, UT 84108 (United States); Ung, Phuc [Monash Institute of Pharmaceutical Sciences, Monash University, Victoria 3052 (Australia); Leaver, Franklin M. [Water & Energy Systems Technology, Inc., Kaysville, UT 84037 (United States); Corbin, Teresa S. [Quality Services Laboratory, Tesoro Refining and Marketing, Salt Lake City, UT 84103 (United States); Tuck, Kellie L., E-mail: kellie.tuck@monash.edu [School of Chemistry, Monash University, Victoria 3800 (Australia); Graham, Bim, E-mail: bim.graham@monash.edu [Monash Institute of Pharmaceutical Sciences, Monash University, Victoria 3052 (Australia); Barrios, Amy M., E-mail: amy.barrios@utah.edu [Department of Medicinal Chemistry, University of Utah College of Pharmacy, Salt Lake City, UT 84108 (United States)

    2015-10-08

    A series of lanthanide-based, azide-appended complexes were investigated as hydrogen sulfide-sensitive probes. Europium complex 1 and Tb complex 3 both displayed a sulfide-dependent increase in luminescence, while Tb complex 2 displayed a decrease in luminescence upon exposure to NaHS. The utility of the complexes for monitoring sulfide levels in industrial oil and water samples was investigated. Complex 3 provided a sensitive measure of sulfide levels in petrochemical water samples (detection limit ∼ 250 nM), while complex 1 was capable of monitoring μM levels of sulfide in partially refined crude oil. - Highlights: • Lanthanide–azide based sulfide sensors were synthesized and characterized. • The probes have excitation and emission profiles compatible with sulfide-contaminated samples from the petrochemical industry. • A terbium-based probe was used to measure the sulfide concentration in oil refinery wastewater. • A europium-based probe had compatibility with partially refined crude oil samples.

  13. Equilibrium of the reaction between dissolved sodium sulfide and biologically produced sulfur

    NARCIS (Netherlands)

    Kleinjan, W.E.; Keizer, de A.; Janssen, A.J.H.

    2005-01-01

    The equilibrium of the heterogeneous reaction between dissolved sodium sulfide and biologically produced sulfur particles has been studied. Biologically produced sulfur was obtained from a bioreactor of a hydrogen sulfide removal process in which the dominating organism is Thiobacillus sp. W5.

  14. Synthetic Fabrication of Nanoscale MoS2-Based Transition Metal Sulfides

    Directory of Open Access Journals (Sweden)

    Jikang Yuan

    2010-01-01

    Full Text Available Transition metal sulfides are scientifically and technologically important materials. This review summarizes recent progress on the synthetic fabrication of transition metal sulfides nanocrystals with controlled shape, size, and surface functionality. Special attention is paid to the case of MoS2 nanoparticles, where organic (surfactant, polymer, inorganic (support, promoter, doping compounds and intercalation chemistry are applied.

  15. Determination of kinetics and stoichiometry of chemical sulfide oxidation in wastewater of sewer networks

    DEFF Research Database (Denmark)

    Nielsen, A.H.; Vollertsen, Jes; Hvitved-jacobsen, Thorkild

    2003-01-01

    A method for determination of kinetics and stoichiometry of chemical sulfide oxidation by dissolved oxygen (DO) in wastewater is presented. The method was particularly developed to investigate chemical sulfide oxidation in wastewater of sewer networks at low DO concentrations. The method is based...

  16. Amperometric inhibitive biosensor based on horseradish peroxidase-nanoporous gold for sulfide determination

    Science.gov (United States)

    Sun, Huihui; Liu, Zhuang; Wu, Chao; Xu, Ping; Wang, Xia

    2016-08-01

    As a well-known toxic pollutant, sulfide is harmful to human health. In this study, a simple and sensitive amperometric inhibitive biosensor was developed for the determination of sulfide in the environment. By immobilizing nanoporous gold (NPG) on glassy carbon electrode (GCE), and encapsulating horseradish peroxidase (HRP) onto NPG, a HRP/NPG/GCE bioelectrode for sulfide detection was successfully constructed based on the inhibition of sulfide on HRP activity with o-Phenylenediamine (OPD) as a substrate. The resulted HRP/NPG/GCE bioelectrode achieved a wide linear range of 0.1–40 μM in sulfide detection with a high sensitivity of 1720 μA mM‑1 cm‑2 and a low detection limit of 0.027 μM. Additionally, the inhibition of sulfide on HRP is competitive inhibition with OPD as a substrate by Michaelis-Menten analysis. Notably, the recovery of HRP activity was quickly achieved by washing the HRP/NPG/GCE bioelectrode using differential pulse voltammetry (DPV) technique in deaerated PBS (50 mM, pH 7.0) for only 60 s. Furthermore, the real sample analysis of sulfide by the HRP/NPG/GCE bioelectrode was achieved. Based on above results, the HRP/NPG/GCE bioelectrode could be a better choice for the real determination of sulfide compared to inhibitive biosensors previously reported.

  17. VAPOR PHASE MERCURY SORPTION BY ORGANIC SULFIDE MODIFIED BIMETALLIC IRON-COPPER NANOPARTICLE AGGREGATES

    Science.gov (United States)

    Novel organic sulfide modified bimetallic iron-copper nanoparticle aggregate sorbent materials have been synthesized for removing elemental mercury from vapor streams at elevated temperatures (120-140 °C). Silane based (disulfide silane and tetrasulfide silane) and alkyl sulfide ...

  18. The impact of electrogenic sulfide oxidation on elemental cycling and solute fluxes in coastal sediment

    NARCIS (Netherlands)

    Rao, A.M.F.; Malkin, S.Y.; Hidalgo-Martinez, S.; Meysman, Filip

    2016-01-01

    Filamentous sulfide oxidizing cable bacteria are capable of linking the oxidation of free sulfide in deep anoxic layers of marine sediments to the reduction of oxygen or nitrate in surface sediments by conducting electrons over centimeter-scale distances. Previous studies have shown that this newly

  19. Spectral properties of zinc sulfide sols stabilized by high-molecular polyvinylpyrrolidone

    Science.gov (United States)

    Evstrop'ev, S. K.; Gatchin, Yu. A.; Evstrop'ev, K. S.; Dukel'skii, K. V.; Kislyakov, I. M.

    2015-12-01

    Spectral properties of zinc sulfide sols stabilized by high-molecular polyvinylpyrrolidone have been studied. It is shown that the absorption spectra of colloidal solutions in the UV spectral range are determined by the quantum-confinement effect, exhibiting a dependence of the absorption edge on the size of zinc sulfide nanocrystals.

  20. Growth kinetics of hydrogen sulfide oxidizing bacteria in corroded concrete from sewers.

    Science.gov (United States)

    Jensen, Henriette Stokbro; Lens, Piet N L; Nielsen, Jeppe L; Bester, Kai; Nielsen, Asbjørn Haaning; Hvitved-Jacobsen, Thorkild; Vollertsen, Jes

    2011-05-30

    Hydrogen sulfide oxidation by microbes present on concrete surfaces of sewer pipes is a key process in sewer corrosion. The growth of aerobic sulfur oxidizing bacteria from corroded concrete surfaces was studied in a batch reactor. Samples of corrosion products, containing sulfur oxidizing bacteria, were suspended in aqueous solution at pH similar to that of corroded concrete. Hydrogen sulfide was supplied to the reactor to provide the source of reduced sulfur. The removal of hydrogen sulfide and oxygen was monitored. The utilization rates of both hydrogen sulfide and oxygen suggested exponential bacterial growth with median growth rates of 1.25 d(-1) and 1.33 d(-1) as determined from the utilization rates of hydrogen sulfide and oxygen, respectively. Elemental sulfur was found to be the immediate product of the hydrogen sulfide oxidation. When exponential growth had been achieved, the addition of hydrogen sulfide was terminated leading to elemental sulfur oxidation. The ratio of consumed sulfur to consumed oxygen suggested that sulfuric acid was the ultimate oxidation product. To the knowledge of the authors, this is the first study to determine the growth rate of bacteria involved in concrete corrosion with hydrogen sulfide as source of reduced sulfur.

  1. Growth kinetics of hydrogen sulfide oxidizing bacteria in corroded concrete from sewers

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, Henriette Stokbro, E-mail: h.s.jensen@sheffield.ac.uk [Department of Biotechnology, Chemistry and Environmental Engineering, Aalborg University, Sohngaardsholmsvej 57, 9000 Aalborg (Denmark); Lens, Piet N.L. [Sub-department of Environmental Technology, Agricultural University of Wageningen, Bomenweg 2, NL-6700-EV Wageningen (Netherlands); Nielsen, Jeppe L.; Bester, Kai; Nielsen, Asbjorn Haaning; Hvitved-Jacobsen, Thorkild; Vollertsen, Jes [Department of Biotechnology, Chemistry and Environmental Engineering, Aalborg University, Sohngaardsholmsvej 57, 9000 Aalborg (Denmark)

    2011-05-30

    Hydrogen sulfide oxidation by microbes present on concrete surfaces of sewer pipes is a key process in sewer corrosion. The growth of aerobic sulfur oxidizing bacteria from corroded concrete surfaces was studied in a batch reactor. Samples of corrosion products, containing sulfur oxidizing bacteria, were suspended in aqueous solution at pH similar to that of corroded concrete. Hydrogen sulfide was supplied to the reactor to provide the source of reduced sulfur. The removal of hydrogen sulfide and oxygen was monitored. The utilization rates of both hydrogen sulfide and oxygen suggested exponential bacterial growth with median growth rates of 1.25 d{sup -1} and 1.33 d{sup -1} as determined from the utilization rates of hydrogen sulfide and oxygen, respectively. Elemental sulfur was found to be the immediate product of the hydrogen sulfide oxidation. When exponential growth had been achieved, the addition of hydrogen sulfide was terminated leading to elemental sulfur oxidation. The ratio of consumed sulfur to consumed oxygen suggested that sulfuric acid was the ultimate oxidation product. To the knowledge of the authors, this is the first study to determine the growth rate of bacteria involved in concrete corrosion with hydrogen sulfide as source of reduced sulfur.

  2. The Determination of Hydrogen Sulfide in Stack Gases, Iodometric Titration After Sulfite Removal.

    Science.gov (United States)

    Robles, E. G.

    The determination of hydrogen sulfide in effluents from coal-fired furnaces and incinerators is complicated by the presence of sulfur oxides (which form acids). Organic compounds also may interfere with or prevent the formation of the cadmium sulfide precipitate or give false positive results because of reaction with iodine. The report presents a…

  3. Functional genes based analysis of sulfur-oxidizing bacteria community in sulfide removing bioreactor.

    Science.gov (United States)

    Luo, Jian-Fei; Lin, Wei-Tie; Guo, Yong

    2011-04-01

    Sulfur-oxidizing bacteria (SOB) are the main microorganisms that participate in the bioremediation of sulfide-rich wastewater. To reveal the SOB community structure and determine which members of SOB contribute to the sulfide oxidation in a sulfide-rich cloth printing and dyeing wastewater treatment plant, specific primer pairs dsrA 625F/877R, soxB 704F/1199R, and sqr 473F/982R based on the SOB functional genes encoding dissimilatory sulfite reductase, sulfate thioesterase/thiohydrolase, and sulfide: quinone oxidoreductase were designed. The restriction fragment length polymorphism analysis showed that the diversity indices and the abundance of each OTU have no significant changes after time, which suggested the SOB community in the sulfide removing bioreactor have high steady phylogenetic analysis of functional gene-based clone libraries detected the SOB from Chlorobia, α-proteobacteria, β-proteobacteria, and γ-proteobacteria. The combined clone library showed the presence of dominant members of the SOB species closely related to families Halothiobacillaceae (17%), Hydrogenophilaceae (14%), and Rhodocyclaceae (13%), which may contribute to the sulfide oxidation in wastewater treatment process. This work provides a precise understanding of SOB microbial community within sulfide removing bioreactor, and the result gives assistance for the optimization of the treatment systems for sulfide biological degradation. © Springer-Verlag 2011

  4. Sulfide oxidation at halo-alkaline conditions in a fed-batch bioreactor

    NARCIS (Netherlands)

    Bosch, van den P.L.F.; Beusekom, van O.C.; Buisman, C.J.N.; Janssen, A.J.H.

    2007-01-01

    A biotechnological process is described to remove hydrogen sulfide (H2S) from high-pressure natural gas and sour gases produced in the petrochemical industry. The process operates at halo-alkaline conditions and combines an aerobic sulfide-oxidizing reactor with an anaerobic sulfate (SO) and

  5. 30 CFR 250.215 - What hydrogen sulfide (H2S) information must accompany the EP?

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false What hydrogen sulfide (H2S) information must... Contents of Exploration Plans (ep) § 250.215 What hydrogen sulfide (H2S) information must accompany the EP? The following H2S information, as applicable, must accompany your EP: (a) Concentration. The estimated...

  6. Vibrational Spectroscopic Studies of Hydrogen, Carbon-Monoxide and Thiophene Adsorption on Ruthenium-Sulfide and Sulfided Ruthenium Catalysts.

    Science.gov (United States)

    Heise, William Herbert

    The "working surface" of ruthenium hydrodesulfurization (HDS) catalysts has been modeled by preadsorption of sulfur, carbon and carbon plus sulfur on Ru(0001). Adsorption and decomposition of thiophene over these surfaces have been investigated using TDS/TPRS, XPS and EELS. Thiophene is proposed to decompose via a three-step mechanism involving: (i) initial thiophene cracking at 120 K yielding surface sulfur and hydrocarbon species, (ii) hydrogen desorption near 230 K providing additional decomposition ensembles and (iii) continued decomposition to form "metallocycle -like" intermediates which retain EELS features similar to thiophene. Preadsorbed carbon or carbon plus sulfur are not as effective for passivation of the surface toward metallocycle formation as preadsorbed sulfur alone. This result is attributed to the fact that carbon deposited from butadiene annealed and decomposed at 700 K forms islands, while sulfur establishes a well-ordered superlattice on the surface. The decrease in metallocycle formation with increasing poison levels appears to explain HDS selectivity and specific activity trends observed in our laboratory from mildly sulfided (10% H_2S/H_2 , 673 K, 2h) ruthenium catalysts retaining submonolayers of sulfur. Incoherent inelastic neutron scattering (IINS) has been used to characterize hydrogen adsorption sites on ruthenium sulfide. Hydrogen resides on sulfur anions to form SH groups, yielding two non-degenerate bending modes at 600 and 710 cm^{-1}. Complementary hydrogen adsorption and H_2/D _2 exchange data suggest that the active sites for hydrogen adsorption may be coordinatively unsaturated S-S anion pairs. Comparison of CO adsorption on sulfided Ru/Al _2O_3 to sulfur precovered Ru(0001) reveals an adsorption site related to edge/corner atoms directly perturbed by sulfur, consistent with previous kinetic studies demonstrating higher specific activity for thiophene HDS over smaller ruthenium crystallites.

  7. Band offset in zinc oxy-sulfide/cubic-tin sulfide interface from X-ray photoelectron spectroscopy

    Science.gov (United States)

    K. C., Sanal; Nair, P. K.; Nair, M. T. S.

    2017-02-01

    Zinc oxy-sulfide, ZnOxS1-x, has been found to provide better band alignment in thin film solar cells of tin sulfide of orthorhombic crystalline structure. Here we examine ZnOxS1-x/SnS-CUB interface, in which the ZnOxS1-x thin film was deposited by radio frequency (rf) magnetron sputtering on SnS thin film of cubic (CUB) crystalline structure with a band gap (Eg) of 1.72 eV, obtained via chemical deposition. X-ray photoelectron spectroscopy provides the valence band maxima of the materials and hence places the conduction band offset of 0.41 eV for SnS-CUB/ZnO0.27S0.73 and -0.28 eV for SnS-CUB/ZnO0.88S0.12 interfaces. Thin films of ZnOxS1-x with 175-240 nm in thickness were deposited from targets prepared with different ZnO to ZnS molar ratios. With the target of molar ratio of 1:13.4, the thin films are of composition ZnO0.27S0.73 with hexagonal crystalline structure and with that of 1:1.7 ratio, it is ZnO0.88S0.12. The optical band gap of the ZnOxS1-x thin films varies from 2.90 eV to 3.21 eV as the sulfur to zinc ratio in the film increases from 0.12:1 to 0.73:1 as determined from X-ray diffraction patterns. Thus, band offsets sought for absorber materials and zinc oxy-sulfide in solar cells may be achieved through a choice of ZnO:ZnS ratio in the sputtering target.

  8. What do we really know about the role of microorganisms in iron sulfide mineral formation?

    Science.gov (United States)

    Picard, Aude; Gartman, Amy; Girguis, Peter

    2016-06-01

    Iron sulfide mineralization in low-temperature systems is a result of biotic and abiotic processes, though the delineation between these two modes of formation is not always straightforward. Here we review the role of microorganisms in the precipitation of extracellular iron sulfide minerals. We summarize the evidence that links sulfur-metabolizing microorganisms and sulfide minerals in nature and we present a critical overview of laboratory-based studies of the nucleation and growth of iron sulfide minerals in microbial cultures. We discuss whether biologically derived minerals are distinguishable from abiotic minerals, possessing attributes that are uniquely diagnostic of biomineralization. These inquiries have revealed the need for additional thorough, mechanistic and high-resolution studies to understand microbially mediated formation of a variety of sulfide minerals across a range of natural environments.

  9. Synthesis of rare earth sulfides and their UV-vis absorption spectra

    Institute of Scientific and Technical Information of China (English)

    YUAN Haibin; ZHANG Jianhui; YU Ruijin; SU Qiang

    2009-01-01

    Rare earth sulfides were systematically synthesized via the sulfurization of their commercial oxide powders using CS2 gas to shorten sulfurization time, and their UV-vis absorption spectra were investigated. The appropriate sulfurization conditions were studied. For the rare earth sulfides with the same crystal structure, the sulfurization temperature showed increasing tendency with the decrease of rare earth element atomic radii. The UV-vis absorption spectra of rare earth sulfides did not depend on the crystal structure of rare earth sulfides, but on the 4f electronic structure of rare earth element. The data showed that the optical band gaps of rare earth sulfides were irregular, and the values ranged from 1.65 to 3.75 eV.

  10. Hydrogen sulfide intervention in focal cerebral ischemia/reperfusion injury in rats.

    Science.gov (United States)

    Li, Xin-Juan; Li, Chao-Kun; Wei, Lin-Yu; Lu, Na; Wang, Guo-Hong; Zhao, Hong-Gang; Li, Dong-Liang

    2015-06-01

    The present study aimed to explore the mechanism underlying the protective effects of hydrogen sulfide against neuronal damage caused by cerebral ischemia/reperfusion. We established the middle cerebral artery occlusion model in rats via the suture method. Ten minutes after middle cerebral artery occlusion, the animals were intraperitoneally injected with hydrogen sulfide donor compound sodium hydrosulfide. Immunofluorescence revealed that the immunoreactivity of P2X7 in the cerebral cortex and hippocampal CA1 region in rats with cerebral ischemia/reperfusion injury decreased with hydrogen sulfide treatment. Furthermore, treatment of these rats with hydrogen sulfide significantly lowered mortality, the Longa neurological deficit scores, and infarct volume. These results indicate that hydrogen sulfide may be protective in rats with local cerebral ischemia/reperfusion injury by down-regulating the expression of P2X7 receptors.

  11. A NEW BIOGENIC SULFIDE CHEMICAL SENSOR FOR MARINE ENVIRONMENTAL MONITORING AND SURVEY

    Institute of Scientific and Technical Information of China (English)

    宋金明; 赵卫东

    2001-01-01

    A new convenient sulfide electrochemical sensor for marine environmental insitumonitoring and real time survey was developed. The new sensor based on a solid Ag2 S membrane electrode has outstanding chemical sensitivity and stability. It responds to the activity of sulfide ions according to a Nernsfian slope of - 31mV/decade. The sensor can be used to determine the total concentration of sulfides ( CT ) by calibrating the pH value of the solution to a standard pH. The practical measurement range for total sulfide concentration is 0.1 - 10 mg/L in seawater. The sensor has a very low potential drift ( < 4mV) during two months in 0.1 mg/L sulfide seawater. This paper describes the preparation of the sensitive membrane and some main properties of the sensor.

  12. A NEW BIOGENIC SULFIDE CHEMICAL SENSOR FOR MARINE ENVIRONMENTAL MONITORING AND SURVEY

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A new convenient sulfide electrochemical sensor for marine environmental in-situ monitoring and real time survey was developed. The new sensor based on a solid Ag2S membrane electrode has outstanding chemical sensitivity and stability. It responds to the activity of sulfide ions according to a Nernstian slope of -31mV/decade. The sensor can be used to determine the total concentration of sulfides (CT) by calibrating the pH value of the solution to a standard pH. The practical measurement range for total sulfide concentration is 0.1-10 mg/L in seawater. The sensor has a very low potential drift (<4mV) during two months in 0.1 mg/L sulfide seawater. This paper describes the preparation of the sensitive membrane and some main properties of the sensor.

  13. Decreasing sulfide generation in sewage by dosing formaldehyde and its derivatives under anaerobic conditions.

    Science.gov (United States)

    Zhang, L; De Gusseme, B; De Schryver, P; Mendoza, L; Marzorati, M; Verstraete, W

    2009-01-01

    Hydrogen sulfide emission in sewers is associated with toxicity, corrosion, odour nuisance and high costs. In this study, a new method to inhibit sulfide generation by means of formaldehyde and its derivatives has been evaluated under anaerobic conditions. The possible impact of formaldehyde on an activated sludge system and an appraisal of the economic aspects are presented as well. A dosage of 19 mg L(-1) formaldehyde resulted in a decrease of the sulfide production of 90%. Dosing of 32 mg L(-1) paraformaldehyde and addition of 111 mg L(-1) ureaformaldehyde were not sufficient to inhibit the sulfide generation in sewage to the same extent. The impacts of 19 mg L(-1) formaldehyde on activated sludge, in terms of COD removal, nitrification rate and oxygen uptake rates, were negligible. This suggests that formaldehyde dosage is a feasible technique to abate the sulfide problem in sewers.

  14. Sulfide and mercury species profiles in two Ontario boreal shield lakes.

    Science.gov (United States)

    Small, Jeff M; Hintelmann, Holger

    2014-09-01

    The cycling of sulfur in freshwater environments plays an important role in the cycling of metals. In this study, acid volatile sulfides were measured at nanomolar levels using a purge-and-trap preconcentration, followed by methylene blue derivatization with HPLC separation and UV-Vis detection. The limit of detection using the preconcentration step was 7.5ngL(-1) or 0.23nM sulfide. Profiles of sulfide and methylmercury were generated for two Ontario lakes. Sulfide concentrations were inversely related to dissolved oxygen concentrations and significant levels of anoxia had developed in both lakes. In both Plastic Lake and Lake 658, mercury concentrations also increased below the oxycline. Lake 658 showed a strong positive correlation between sulfide and methylmercury (CMeHg=2×10(-6)⋅Csulfide+0.198; r=0.96, p=1.2×10(-5)), at the time of sampling.

  15. What do we really know about the role of microorganisms in iron sulfide mineral formation?

    Science.gov (United States)

    Picard, Aude A.; Gartman, Amy; Girguis, Peter R.

    2016-01-01

    Iron sulfide mineralization in low-temperature systems is a result of biotic and abiotic processes, though the delineation between these two modes of formation is not always straightforward. Here we review the role of microorganisms in the precipitation of extracellular iron sulfide minerals. We summarize the evidence that links sulfur-metabolizing microorganisms and sulfide minerals in nature and we present a critical overview of laboratory-based studies of the nucleation and growth of iron sulfide minerals in microbial cultures. We discuss whether biologically derived minerals are distinguishable from abiotic minerals, possessing attributes that are uniquely diagnostic of biomineralization. These inquiries have revealed the need for additional thorough, mechanistic and high-resolution studies to understand microbially mediated formation of a variety of sulfide minerals across a range of natural environments.

  16. QEXAFS study of the sulfidation of NiMo/Al2O3 hydrotreating catalysts.

    Science.gov (United States)

    Cattaneo, R; Shido, T; Prins, R

    2001-03-01

    Quick-scanning extended X-ray absorption fine structure (QEXAFS) spectroscopy was employed to investigate in situ the sulfidation of Mo and Ni in y-AI2O3-supported hydrotreating catalysts modified with chelating ligands. Mo K-edge QEXAFS enabled the detection of an intermediate product in the sulfidation of Mo. The parameters obtained from the fits of the QEXAFS spectra showed that this product consists of compounds similar to Mo2S2-(12) or Mo3S2-(13). QEXAFS also demonstrated that the sulfidation of Ni is strongly influenced by the presence of chelating ligands. Classical EXAFS spectra of the sulfided catalysts showed that Ni forms small sulfided clusters, the size of which is influenced by the presence or absence of the chelating agents.

  17. Repulsive Interaction of Sulfide Layers on Compressor Impeller Blades Remanufactured Through Plasma Spray Welding

    Science.gov (United States)

    Chang, Y.; Zhou, D.; Wang, Y. L.; Huang, H. H.

    2016-12-01

    This study investigated the repulsive interaction of sulfide layers on compressor impeller blades remanufactured through plasma spray welding (PSW). Sulfide layers on the blades made of FV(520)B steel were prepared through multifarious corrosion experiments, and PSW was utilized to remanufacture blade specimens. The specimens were evaluated through optical microscopy, scanning electron microscopy, energy-dispersive spectroscopy, 3D surface topography, x-ray diffraction, ImageJ software analysis, Vicker's micro-hardness test and tensile tests. Results showed a large number of sulfide inclusions in the fusion zone generated by sulfide layers embodied into the molten pool during PSW. These sulfide inclusions seriously degraded the mechanical performance of the blades remanufactured through PSW.

  18. Hydrogen sulfide intervention in focal cerebral ischemia/reperfusion injury in rats

    Directory of Open Access Journals (Sweden)

    Xin-juan Li

    2015-01-01

    Full Text Available The present study aimed to explore the mechanism underlying the protective effects of hydrogen sulfide against neuronal damage caused by cerebral ischemia/reperfusion. We established the middle cerebral artery occlusion model in rats via the suture method. Ten minutes after middle cerebral artery occlusion, the animals were intraperitoneally injected with hydrogen sulfide donor compound sodium hydrosulfide. Immunofluorescence revealed that the immunoreactivity of P2X 7 in the cerebral cortex and hippocampal CA1 region in rats with cerebral ischemia/reperfusion injury decreased with hydrogen sulfide treatment. Furthermore, treatment of these rats with hydrogen sulfide significantly lowered mortality, the Longa neurological deficit scores, and infarct volume. These results indicate that hydrogen sulfide may be protective in rats with local cerebral ischemia/reperfusion injury by down-regulating the expression of P2X 7 receptors.

  19. Atomic layer deposition of metal sulfide thin films using non-halogenated precursors

    Energy Technology Data Exchange (ETDEWEB)

    Martinson, Alex B. F.; Elam, Jeffrey W.; Pellin, Michael J.

    2015-05-26

    A method for preparing a metal sulfide thin film using ALD and structures incorporating the metal sulfide thin film. The method includes providing an ALD reactor, a substrate, a first precursor comprising a metal and a second precursor comprising a sulfur compound. The first and the second precursors are reacted in the ALD precursor to form a metal sulfide thin film on the substrate. In a particular embodiment, the metal compound comprises Bis(N,N'-di-sec-butylacetamidinato)dicopper(I) and the sulfur compound comprises hydrogen sulfide (H.sub.2S) to prepare a Cu.sub.2S film. The resulting metal sulfide thin film may be used in among other devices, photovoltaic devices, including interdigitated photovoltaic devices that may use relatively abundant materials for electrical energy production.

  20. A fatal case of hydrogen sulfide poisoning in a geothermal power plant.

    Science.gov (United States)

    Kage, S; Ito, S; Kishida, T; Kudo, K; Ikeda, N

    1998-07-01

    An adult man entered an oil separator room to remove waste oil from a vacuum pump in a geothermal power plant. He suddenly collapsed and died soon after. Since hydrogen sulfide gas was detected in the atmosphere at the scene of the accident, poisoning by this gas was suspected and toxicological analysis of sulfide and thiosulfate in blood, brain, lung, femoral muscle was made using the extractive alkylation technique combined with gas chromatography/mass spectrometry (GC/MS). The concentrations of sulfide in these tissues were similar to those previously reported for fatal cases of hydrogen sulfide gas. The concentration of thiosulfate in the blood was at least 48 times higher than the level in control samples. Based on these results, the cause of death was attributed to hydrogen sulfide gas poisoning.