The Experts below are selected from a list of 1401 Experts worldwide ranked by ideXlab platform
Yi Zhang - One of the best experts on this subject based on the ideXlab platform.
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Cleaner production of vanadium oxides by cation-exchange membrane-assisted electrolysis of Sodium vanadate solution
Hydrometallurgy, 2017Co-Authors: Shili Zheng, Shaona Wang, Hao Du, Yi ZhangAbstract:Abstract We herein report the development of a membrane-assisted electrochemical method for separating Sodium and vanadium from a Sodium Orthovanadate solution. During the employed electrolysis process, Na+ ions in the anode chamber pass through the cation-exchange membrane and combine with OH− ions in the cathode chamber to produce a concentrated NaOH solution, resulting in lowering of the pH in the anode chamber from 13.7 to 1.81. This reaction results in the precipitation of 92.60%-pure vanadium oxide. The effects of the electrolysis time, current density, solution temperature, and initial NaOH concentration in the cathode chamber on the process were investigated. It was found that increases in the current density and solution temperature decreased the initial NaOH concentration in the cathode chamber and enhanced Sodium and vanadium separation. Using a current density of 600 A/m2 and a solution temperature of 338 K, 3641 kW·h of energy was consumed to produce 1 t of NaOH and 0.75 t of V2O5 over an electrolysis time of 7 h.
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Cleaner production of vanadium oxides by cation-exchange membrane-assisted electrolysis of Sodium vanadate solution
'Elsevier BV', 2017Co-Authors: Bo Pan, Zheng Shili, Wang Shaona, Du Hao, Jin Wei, Liu Biao, Yi ZhangAbstract:We herein report the development of a membrane-assisted electrochemical method for separating Sodium and vanadium from a Sodium Orthovanadate solution. During the employed electrolysis process, Na+ ions in the anode chamber pass through the cation-exchange membrane and combine with OH- ions in the cathode chamber to produce a concentrated NaOH solution, resulting in lowering of the pH in the anode chamber from 13.7 to 1.81. This reaction results in the precipitation of 92.60%-pure vanadium oxide. The effects of the electrolysis time, current density, solution temperature, and initial NaOH concentration in the cathode chamber on the process were investigated. It was found that increases in the current density and solution temperature decreased the initial NaOH concentration in the cathode chamber and enhanced Sodium and vanadium separation. Using a current density of 600 A/m(2) and a solution temperature of 338 K, 3641 kW.h of energy was consumed to produce 1 t of NaOH and 0.75 t of V2O5 over an electrolysis time of 7 h. (C) 2017 Elsevier B.V. All rights reserved.
Jose Roberto Meyerfernandes - One of the best experts on this subject based on the ideXlab platform.
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interaction between trypanosoma rangeli and the rhodnius prolixus salivary gland depends on the phosphotyrosine ecto phosphatase activity of the parasite
International Journal for Parasitology, 2012Co-Authors: Andre L A Dossantos, Claudia F Dick, Michele Alvesbezerra, Katia C Gondim, Lisvane Silva Paes, Thais S Silveira, Jose Roberto MeyerfernandesAbstract:Trypanosoma rangeli is the trypanosomatid that colonizes the salivary gland of its insect vector, with a profound impact on the feeding capacity of the insect. In this study we investigated the role of the phosphotyrosine (P-Tyr) ecto-phosphatase activity of T. rangeli in its interaction with Rhodnius prolixus salivary glands. Long but not short epimastigotes adhered to the gland cells and the strength of interaction correlated with the enzyme activity levels in different strains. Differential interference contrast microscopy demonstrated that clusters of parasites are formed in most cases, suggesting cooperative interaction in the adhesion process. The tightness of the correlation was evidenced by modulating the P-Tyr ecto-phosphatase activity with various concentrations of inhibitors. Sodium Orthovanadate, ammonium molybdate and zinc chloride decreased the interaction between T. rangeli and R. prolixus salivary glands in parallel. Levamisole, an inhibitor of alkaline phosphatases, affected neither process. EDTA strongly inhibited adhesion and P-Tyr ecto-phosphatase activity to the same extent, an effect that was no longer seen if the parasites were pre-incubated with the chelator and then washed. When the P-Tyr ecto-phosphatase of living T. rangeli epimastigotes was irreversibly inactivated with Sodium Orthovanadate and the parasite cells were then injected into the insect thorax, colonization of the salivary glands was greatly depressed for several days after blood feeding. Addition of P-Tyr ecto-phosphatase substrates such as p-nitrophenyl phosphate (pNPP) and P-Tyr inhibited the adhesion of T. rangeli to salivary glands, but P-Ser, P-Thr and β-glycerophosphate were completely ineffective. Immunoassays using anti-P-Tyr-residues revealed a large number of P-Tyr-proteins in extracts of R. prolixus salivary glands, which could be potentially targeted by T. rangeli during adhesion. These results indicate that dephosphorylation of structural P-Tyr residues on the gland cell surfaces, mediated by a P-Tyr ecto-phosphatase of the parasite, is a key event in the interaction between T. rangeli and R. prolixus salivary glands.
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trypanosoma rangeli a possible role for ecto phosphatase activity on cell proliferation
Experimental Parasitology, 2009Co-Authors: Andre L Fonsecadesouza, Andre Luiz Araujo Dos Santos, Claudia F Dick, Fabio V Fonseca, Jose Roberto MeyerfernandesAbstract:Abstract Here we demonstrate for the first time that growth of Trypanosoma rangeli , a protozoa parasite, is strongly dependent on the presence of inorganic phosphate (Pi) in the culture medium and that the replacement of the inorganic phosphate in the culture medium by β-glycerophosphate, a substrate for phosphatases lead the cells to achieve its maximal growth. The ecto-phosphatase activity present on the external surface of T. rangeli decreased during the growth phase of the parasite, suggesting that this enzyme could be important for the development. Accordingly, the inhibition of this ecto-phosphatase activity by Sodium Orthovanadate also inhibited the proliferation of T. rangeli . Parasites maintained in a Pi-starved culture medium (2 mM Pi) had 4-fold more ecto-phosphatase activity as compared to parasites maintained in a Pi-supplemented culture medium (50 mM Pi). Altogether, these results presented here suggest that this ecto-phosphatase activity leads to hydrolysis of phosphorylated compounds present in the extracellular medium, which could contribute to the acquisition of inorganic phosphate during the development of T. rangeli epimastigotes.
Shili Zheng - One of the best experts on this subject based on the ideXlab platform.
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Cleaner production of vanadium oxides by cation-exchange membrane-assisted electrolysis of Sodium vanadate solution
Hydrometallurgy, 2017Co-Authors: Shili Zheng, Shaona Wang, Hao Du, Yi ZhangAbstract:Abstract We herein report the development of a membrane-assisted electrochemical method for separating Sodium and vanadium from a Sodium Orthovanadate solution. During the employed electrolysis process, Na+ ions in the anode chamber pass through the cation-exchange membrane and combine with OH− ions in the cathode chamber to produce a concentrated NaOH solution, resulting in lowering of the pH in the anode chamber from 13.7 to 1.81. This reaction results in the precipitation of 92.60%-pure vanadium oxide. The effects of the electrolysis time, current density, solution temperature, and initial NaOH concentration in the cathode chamber on the process were investigated. It was found that increases in the current density and solution temperature decreased the initial NaOH concentration in the cathode chamber and enhanced Sodium and vanadium separation. Using a current density of 600 A/m2 and a solution temperature of 338 K, 3641 kW·h of energy was consumed to produce 1 t of NaOH and 0.75 t of V2O5 over an electrolysis time of 7 h.
Nan Zhao - One of the best experts on this subject based on the ideXlab platform.
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hydrogen sulfide mediates k and na homeostasis in the roots of salt resistant and salt sensitive poplar species subjected to nacl stress
Frontiers in Plant Science, 2018Co-Authors: Nan Zhao, Huipeng Zhu, Huilong Zhang, Jian Sun, Jinchi Zhou, Chen Deng, Yuhong Zhang, Rui Zhao, Xiaoyang ZhouAbstract:Non-invasive micro-test techniques (NMT) were used to analyze NaCl-altered flux profiles of K+, Na+, and H+ in roots and effects of NaHS (a H2S donor) on root ion fluxes in two contrasting poplar species, Populus euphratica (salt-resistant) and Populus popularis (salt-sensitive). Both poplar species displayed a net K+ efflux after exposure to salt shock (100 mM NaCl), as well as after short-term (24 h), and long-term (5 d) saline treatment (50 mM NaCl, referred to as salt stress). NaHS (50 M) restricted NaCl-induced K+ efflux in roots irrespective of the duration of salt exposure, but K+ efflux was not pronounced in data collected from the long-term salt stress treatment of P. euphratica. The NaCl-induced K+ efflux was inhibited by a K+ channel blocker, tetraethylammonium chloride (TEA) in P. popularis root samples, but K+ loss increased with a specific inhibitor of plasma membrane H+-ATPase, Sodium Orthovanadate, in both poplar species under long-term salt stress and NaHS treatment. This indicates that NaCl-induced K+ loss was through depolarization-activated K+ channels. NaHS caused increased Na+ efflux and a corresponding increase in H+ influx for poplar roots subjected to both the short- and long-term salt stress. The NaHS-enhanced H+ influx was not significant in P. euphratica samples subjected to short term salt stress. Both Sodium Orthovanadate and amiloride (a Na+/H+ antiporter inhibitor) effectively inhibited the NaHS-augmented Na+ efflux, indicating that the H2S-enhanced Na+ efflux was due to active Na+ exclusion across the plasma membrane. We therefore conclude that the beneficial effects of H2S probably arise from upward regulation of the Na+/H+ antiport system (H+ pumps and Na+/H+ antiporters), which promote exchange of Na+ with H+ across the plasma membrane and simultaneously restricted the channel-mediated K+ loss that activated by membrane depolarization.
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Hydrogen Sulfide Mediates K+ and Na+ Homeostasis in the Roots of Salt-Resistant and Salt-Sensitive Poplar Species Subjected to NaCl Stress
Frontiers Media S.A., 2018Co-Authors: Nan Zhao, Huipeng Zhu, Huilong Zhang, Jian Sun, Jinchi Zhou, Chen Deng, Yuhong Zhang, Rui Zhao, Xiaoyang ZhouAbstract:Non-invasive micro-test techniques (NMT) were used to analyze NaCl-altered flux profiles of K+, Na+, and H+ in roots and effects of NaHS (a H2S donor) on root ion fluxes in two contrasting poplar species, Populus euphratica (salt-resistant) and Populus popularis (salt-sensitive). Both poplar species displayed a net K+ efflux after exposure to salt shock (100 mM NaCl), as well as after short-term (24 h), and long-term (LT) (5 days) saline treatment (50 mM NaCl, referred to as salt stress). NaHS (50 μM) restricted NaCl-induced K+ efflux in roots irrespective of the duration of salt exposure, but K+ efflux was not pronounced in data collected from the LT salt stress treatment of P. euphratica. The NaCl-induced K+ efflux was inhibited by a K+ channel blocker, tetraethylammonium chloride (TEA) in P. popularis root samples, but K+ loss increased with a specific inhibitor of plasma membrane (PM) H+-ATPase, Sodium Orthovanadate, in both poplar species under LT salt stress and NaHS treatment. This indicates that NaCl-induced K+ loss was through depolarization-activated K+ channels. NaHS caused increased Na+ efflux and a corresponding increase in H+ influx for poplar roots subjected to both the short- and LT salt stress. The NaHS-enhanced H+ influx was not significant in P. euphratica samples subjected to short term salt stress. Both Sodium Orthovanadate and amiloride (a Na+/H+ antiporter inhibitor) effectively inhibited the NaHS-augmented Na+ efflux, indicating that the H2S-enhanced Na+ efflux was due to active Na+ exclusion across the PM. We therefore conclude that the beneficial effects of H2S probably arise from upward regulation of the Na+/H+ antiport system (H+ pumps and Na+/H+ antiporters), which promote exchange of Na+ with H+ across the PM and simultaneously restricted the channel-mediated K+ loss that activated by membrane depolarization
Xuewen Li - One of the best experts on this subject based on the ideXlab platform.
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first evidence on different transportation modes of arsenic and phosphorus in arsenic hyperaccumulator pteris vittata
Environmental Pollution, 2012Co-Authors: Zechun Huang, Tongbin Chen, Xuewen LiAbstract:Arsenic (As) reduction and translocation are key processes for As hyperaccumulation by the hyperaccumulator Pteris vittata L. Micro-X-ray adsorption spectroscopy of P. vittata’s rhizoid tissues revealed that As reduction mainly occurred in endodermis during translocation from epidermis to vascular bundle. Prior to reduction, arsenate (As (V)) translocation was an active process requiring energy and employing a phosphate (P) transporter. Use of a synchrotron X-ray microprobe showed that As (V) and P were cotransported and that this process could be enhanced by As (V) exposure or P deficiency but restrained by energy release inhibition caused by 2,4-dinitrophenol or Sodium Orthovanadate. In contrast, after As reduction, As(III) translocation differed from P translocation and was more efficient, appearing free from the apparent endodermal blockage. The results here revealed the role of the P transporter on As translocation as well as the key role of As reduction in As hyperaccumulation by P. vittata.