Tributyl phosphate(TBP) was employed for the Bi(Ⅲ) extraction from hydrochloric acid medium.The effects of extraction time and material concentration were examined.The replacement mechanism between the anion(Cl^-) an...Tributyl phosphate(TBP) was employed for the Bi(Ⅲ) extraction from hydrochloric acid medium.The effects of extraction time and material concentration were examined.The replacement mechanism between the anion(Cl^-) and TBP was proposed for extraction.The results show the species extracted into the organic phase were found to be mainly BiCl_3·x TBP(x=2 or 3).Thermodynamic parameters of the extraction reaction were obtained from the thermodynamics analysis,which illustrates that higher temperatures show a negative effect on the extraction.Extraction isotherm was obtained with 2.16 mol/L TBP for a typical solution containing 0.1 mol/L of bismuth and 1.0 mol/L of hydrochloric acid.About 98.5 % of bismuth has been extracted from the leaching solution under the optimum condition.Moreover,oxalate was explored as a precipitation stripping agent for BiCl_3·x TBP(x=2 or 3) complexes,by which Bi(Ⅲ) was stripped in the form of Bi_2(C_2O_4)_3·7H_2O.A stripping efficiency of 99.3% was obtained in only one stage at the phase ratio of 1 and TBP also could be recycled.Therefore,the method is an efficient,effective and highly selective approach to extract Bi(Ⅲ) and to recover metal bismuth.展开更多
Dishevelled （Dvl） is a highly conserved protein family that plays an important role in mediating Wnt signal- ing from membrane to cytoplasm. Recently we reported that Dvl also functions in the nucleus by stabilizing...Dishevelled （Dvl） is a highly conserved protein family that plays an important role in mediating Wnt signal- ing from membrane to cytoplasm. Recently we reported that Dvl also functions in the nucleus by stabilizing the β-catenin/TCFs transcriptional complex. Here we describe that Dvl may function as a repressor of NF-kB. Our data show that Dvl directly binds to p65 and their interaction occurs in the nucleus. Dvl expression inhibits p65-mediated or TNF-α-stimulated activation of the NF-KB dependent reporter. This action of Dvl, however, is not dependent on Wnt or its downstream effector β-catenin. Chromatin immunoprecipitation assay shows that recruitment of p65 to the promoters of NF-KB target genes is significantly enhanced when expression of Dvl is knocked down. Consistently, the expression level of a subset of NF-KB target genes is also increased after knock-down of Dvl. Moreover, our data suggest that Dvl may relieve the anti-apoptotic effect of NF-KB, thus play a role in promoting apoptosis. Therefore, this work demonstrates a novel function of Dvl in modulating NF-KB-regulated gene transcription.展开更多
基金Project(2011AA061002)supported by the High-Tech Research and Development Program of ChinaProject(2010SK2010)supported by the Key Program of Science and Technology of Hunan Province,ChinaProject supported by the Hunan Nonferrous Metals Fund,China
文摘Tributyl phosphate(TBP) was employed for the Bi(Ⅲ) extraction from hydrochloric acid medium.The effects of extraction time and material concentration were examined.The replacement mechanism between the anion(Cl^-) and TBP was proposed for extraction.The results show the species extracted into the organic phase were found to be mainly BiCl_3·x TBP(x=2 or 3).Thermodynamic parameters of the extraction reaction were obtained from the thermodynamics analysis,which illustrates that higher temperatures show a negative effect on the extraction.Extraction isotherm was obtained with 2.16 mol/L TBP for a typical solution containing 0.1 mol/L of bismuth and 1.0 mol/L of hydrochloric acid.About 98.5 % of bismuth has been extracted from the leaching solution under the optimum condition.Moreover,oxalate was explored as a precipitation stripping agent for BiCl_3·x TBP(x=2 or 3) complexes,by which Bi(Ⅲ) was stripped in the form of Bi_2(C_2O_4)_3·7H_2O.A stripping efficiency of 99.3% was obtained in only one stage at the phase ratio of 1 and TBP also could be recycled.Therefore,the method is an efficient,effective and highly selective approach to extract Bi(Ⅲ) and to recover metal bismuth.
基金This work was supported by the Ministry of Science and Technology of China （2010CB912100 and 2007CB914500）, the National Natural Science Foundation of China （30821065, 30930052 and 90813024）, and the Science and Technology Commission of Shanghai Municipality.
文摘Dishevelled （Dvl） is a highly conserved protein family that plays an important role in mediating Wnt signal- ing from membrane to cytoplasm. Recently we reported that Dvl also functions in the nucleus by stabilizing the β-catenin/TCFs transcriptional complex. Here we describe that Dvl may function as a repressor of NF-kB. Our data show that Dvl directly binds to p65 and their interaction occurs in the nucleus. Dvl expression inhibits p65-mediated or TNF-α-stimulated activation of the NF-KB dependent reporter. This action of Dvl, however, is not dependent on Wnt or its downstream effector β-catenin. Chromatin immunoprecipitation assay shows that recruitment of p65 to the promoters of NF-KB target genes is significantly enhanced when expression of Dvl is knocked down. Consistently, the expression level of a subset of NF-KB target genes is also increased after knock-down of Dvl. Moreover, our data suggest that Dvl may relieve the anti-apoptotic effect of NF-KB, thus play a role in promoting apoptosis. Therefore, this work demonstrates a novel function of Dvl in modulating NF-KB-regulated gene transcription.
