A series of extraction equilibrium experiments for aminobenzoic acid with di(2-ethylhexyl)phosphoric acid (D2EHPA) dissolved in n-octane or 1-octanol was carried out. The effects of aminobenzoic acid concentration,D2E...A series of extraction equilibrium experiments for aminobenzoic acid with di(2-ethylhexyl)phosphoric acid (D2EHPA) dissolved in n-octane or 1-octanol was carried out. The effects of aminobenzoic acid concentration,D2EHPA concentration and pH on the distribution ratio were discussed in detail. The infrared spectra of the organic phase loaded with solute illustrated that pH had little effect on the structure of the complex formed. There proceed ion association and cation-exchange.reaction in the extraction. An expression of the equilibrium distribution was proposed.展开更多
Objective This study was conducted to examine the absorption and translocation of conjugated bile acids(BAs)in Calculus bovis and its substitutes to detect differences in these materials.Methods A Caco-2 monolayer cel...Objective This study was conducted to examine the absorption and translocation of conjugated bile acids(BAs)in Calculus bovis and its substitutes to detect differences in these materials.Methods A Caco-2 monolayer cell model was used to compare the apparent permeability coefficient(Papp)value and efflux ratio(ER)of BAs in natural cow-bezoar(NCB),artificial cow-bezoar(ACB),and in vitro cultured cow-bezoar(Ivt-CCB).Papp and ER values were determined by liquid chromatography-mass spectrometry.Samples were separated on an analytical column.Results The distribution of BAs in NCB was significantly different from that in ACB and Ivt-CCB.The percentages of conjugated BAs were significantly higher in NCB than in the two substitutes.The distribution differences of conjugated and unconjugated BAs can be used to distinguish costly NCB from relatively inexpensive substitutes.Conclusion The transport characteristics of BAs in Ivt-CCB were more consistent with NCB than with ACB,even when the proportions of BAs in Ivt-CCB were closer to those of ACB.展开更多
Racemic 2-n-butylbutanedioic acid 4-t-butyl esters were synthesized from methyl hexanoate and t-butyl α-iodoacetate via alkylation and subsequently selective hydrolyzation. The （R）-and （S）-2-n-butylbutanedioic ac...Racemic 2-n-butylbutanedioic acid 4-t-butyl esters were synthesized from methyl hexanoate and t-butyl α-iodoacetate via alkylation and subsequently selective hydrolyzation. The （R）-and （S）-2-n-butylbutanedioic acid 4-t-butyl esters were obtained by the resolution of the above-mentioned racemic compounds with（S）-（ - ） or（R）-（ ＋ ）-α- methylbenzylamine, respectively. The e.e. values of the two optical active products were determined to be above 99% by HPLC after the formation of two pairs of diastereoisomers with（R）-（ ＋ ）-α-methylbenzylamine and（S）- phenylalanine methyl ester.展开更多
The variation characteristics of acid rain and the relationship between the formation of acid rain and meteorological conditions were analyzed based on the observation data and meteorological records collected from ac...The variation characteristics of acid rain and the relationship between the formation of acid rain and meteorological conditions were analyzed based on the observation data and meteorological records collected from acid rain observation station in Dalian over 2006-2009.The results showed that Dalian was one of the regions with strong acid rain in northern China,with the frequency of 66% and pH value of 3.49.The acidity was the strongest in fall and weakest in spring;and the maximum and minimum frequencies were in summer and in winter respectively.Frequency of acid rain was inversely proportional to wind speed and concentration of inhalable particles in Dalian;acid rain occurred easily in foggy weather due to the steady stratification and abundant moisture;continuous precipitation did not mean the reduction of acidic material in the air,and the rainfall with increased acidity in the second day accounted for 42% in continuous precipitation cases.展开更多
A two-step leaching method in combination of acid and ethylene diaminetetraacetic acid disodium （EDTA-Na2） was applied to extract metals such as Cd, Cu, Fe, Pb and Zn from a zinc smelting slag. The results show that...A two-step leaching method in combination of acid and ethylene diaminetetraacetic acid disodium （EDTA-Na2） was applied to extract metals such as Cd, Cu, Fe, Pb and Zn from a zinc smelting slag. The results show that the extraction rates of Cd, Cu, Fe and Zn in slag reach 88.3%, 54.1%, 69.6% and 54.7%, respectively, while the extraction rate of Pb is only 0.05% leached with 1.25 mol/L sulfuric acid under the conditions of the ratio of slag to liquid of 100 g/L, 65 ℃ and 120 r/min for 2 h. However, Pb extraction rate from 1.25 mol/L sulfuric acid leached residue reaches as high as 66.5% by using 0.1 mol/L EDTA-Na2 solution. The results indicate that two-step sequential extraction procedure combining 1.25 mol/L sulfuric acid and 0.1 mol/L EDTA-Na2 solution can extensively extract Cd, Cu, Fe, Pb and Zn from zinc smelting slag.展开更多
AIM: To identify hepatitis C virus(HCV) core protein epitopes recognized by HLA-A2 restricted cytotoxic T lymphocyte (CTL). METHODS: Utilizing the method of computer prediction followed by a 4h(51)Cr release assay con...AIM: To identify hepatitis C virus(HCV) core protein epitopes recognized by HLA-A2 restricted cytotoxic T lymphocyte (CTL). METHODS: Utilizing the method of computer prediction followed by a 4h(51)Cr release assay confirmation. RESULTS: The results showed that peripheral blood mononuclear cells (PBMC) obtained from two HLA-A2 positive donors who were infected with HCV could lyse autologous target cells labeled with peptide "ALAHGVRAL (core 150-158)". The rates of specific lysis of the cells from the two donors were 37.5% and 15.8%, respectively. Blocking of the CTL response with anti-CD4 mAb caused no significant decrease of the specific lysis. But blocking of CTL response with anti-CD8 mAb could abolish the lysis. CONCLUSION: The peptide (core 150-158) is the candidate epitope recognized by HLAA2 restricted CTL.展开更多
目的评估国家早期预警评分2(NEWS2)联合动脉血乳酸水平预测重症社区获得性肺炎(SCAP)患者短期预后的价值。方法回顾性收集某三甲医院2017年5月—2022年5月收治的成人SCAP住院患者的中性粒细胞与淋巴细胞比值(NLR)、氧合指数、NEWS 2评...目的评估国家早期预警评分2(NEWS2)联合动脉血乳酸水平预测重症社区获得性肺炎(SCAP)患者短期预后的价值。方法回顾性收集某三甲医院2017年5月—2022年5月收治的成人SCAP住院患者的中性粒细胞与淋巴细胞比值(NLR)、氧合指数、NEWS 2评分及急性生理学与慢性健康状况评分Ⅱ(APACHEⅡ)等资料。根据28天预后分为存活组和死亡组,比较组间差异,并分析主要指标的相关性。采用多因素logistic回归分析和受试者工作特征(ROC)曲线分析NEWS2评分、乳酸以及两者联合对SCAP患者死亡风险的预测价值。结果共入组97例SCAP患者,存活65例,死亡32例,28天病死率32.99%。与存活组比较,死亡组患者入院时NEWS2评分、APACHEⅡ评分、降钙素原(PCT)、NLR及血乳酸均较高,CD3^(+)CD4^(+)T淋巴细胞、氧合指数明显降低,差异均有统计学意义(均P<0.05)。血乳酸与NEWS2评分、APACHEⅡ评分均具有较好的相关性(r值分别为0.411、0.709,均P<0.01)。多因素logistic回归分析显示,NEWS2评分和血乳酸为SCAP患者28天死亡的独立危险因素(OR=1.422,95%CI:1.043~1.938;OR=1.635,95%CI:1.072~2.492,均P<0.05)。ROC曲线分析显示,与传统指标APACHEⅡ评分相比较,NEWS2评分、血乳酸对SCAP患者28天死亡的预测价值良好[曲线下面积(AUC)分别为0.740、0.721 VS 0.772,Z值为0.506、1.141,均P>0.05];当NEWS2评分、血乳酸最佳截断值分别是7分、1.96 mmol/L时,灵敏度分别为81.3%、68.7%,特异度分别为63.1%、75.4%。NEWS2评分联合血乳酸显示出更高的预测价值(AUC为0.776 VS 0.772),并且具有较高的灵敏度(84.4%)和特异度(70.8%)。结论入院时NEWS2评分、血乳酸是SCAP患者28天死亡的独立危险因素,均具有较高的预测价值;NEWS2评分联合血乳酸预测SCAP患者短期预后的价值更高,优于单个评分。展开更多
Synthesis of polyols from carbon dioxide（CO2） is attractive from the viewpoint of sustainable development of polyurethane industry;it is also interesting to adjust the structure of the CO2-polyols for versatile requ...Synthesis of polyols from carbon dioxide（CO2） is attractive from the viewpoint of sustainable development of polyurethane industry;it is also interesting to adjust the structure of the CO2-polyols for versatile requirement of polyurethane.However,when renewable malonic acid was used as a starter,the copolymerization reaction of CO2 and propylene oxide（PO） was uncontrollable,since it proceeded slowly（13 h） and produced 40.4 wt%of byproduct propylene carbonate（PC） with a low productivity of 0.34kg/g.A careful analysis disclosed that the acid value of the copolymerization medium was the key factor for controlling the copolymerization reaction.Therefore,a preactivation approach was developed to dramatically reduce the acid value to 0.6mg（KOH）/gby homopolymerization of PO into oligo-ether-diol under the initiation of malonic acid,which ensured the controllable copolymerization,where the copolymerization time could be shortened by 77%from 13 to 3 h,the PC content was reduced by 76%from 40.4 wt%to 9.4 wt%,and the productivity increased by 61%from 0.34 to 0.55 kg/g.Moreover,by means of preactivation approach,the molecular weight as well as the carbonate unit content in the CO2-diol was also controllable.展开更多
文摘A series of extraction equilibrium experiments for aminobenzoic acid with di(2-ethylhexyl)phosphoric acid (D2EHPA) dissolved in n-octane or 1-octanol was carried out. The effects of aminobenzoic acid concentration,D2EHPA concentration and pH on the distribution ratio were discussed in detail. The infrared spectra of the organic phase loaded with solute illustrated that pH had little effect on the structure of the complex formed. There proceed ion association and cation-exchange.reaction in the extraction. An expression of the equilibrium distribution was proposed.
基金support from the Youth Development Research Foundation of NIFDC(2014A1)National Science and Technology Major Project(2017ZX09101002-002-008)the National Natural Science Foundation of China(No.81403171 and No.81603517)
文摘Objective This study was conducted to examine the absorption and translocation of conjugated bile acids(BAs)in Calculus bovis and its substitutes to detect differences in these materials.Methods A Caco-2 monolayer cell model was used to compare the apparent permeability coefficient(Papp)value and efflux ratio(ER)of BAs in natural cow-bezoar(NCB),artificial cow-bezoar(ACB),and in vitro cultured cow-bezoar(Ivt-CCB).Papp and ER values were determined by liquid chromatography-mass spectrometry.Samples were separated on an analytical column.Results The distribution of BAs in NCB was significantly different from that in ACB and Ivt-CCB.The percentages of conjugated BAs were significantly higher in NCB than in the two substitutes.The distribution differences of conjugated and unconjugated BAs can be used to distinguish costly NCB from relatively inexpensive substitutes.Conclusion The transport characteristics of BAs in Ivt-CCB were more consistent with NCB than with ACB,even when the proportions of BAs in Ivt-CCB were closer to those of ACB.
基金Supported by the National Basic Research Priority Program(No. 2003CCA027).
文摘Racemic 2-n-butylbutanedioic acid 4-t-butyl esters were synthesized from methyl hexanoate and t-butyl α-iodoacetate via alkylation and subsequently selective hydrolyzation. The （R）-and （S）-2-n-butylbutanedioic acid 4-t-butyl esters were obtained by the resolution of the above-mentioned racemic compounds with（S）-（ - ） or（R）-（ ＋ ）-α- methylbenzylamine, respectively. The e.e. values of the two optical active products were determined to be above 99% by HPLC after the formation of two pairs of diastereoisomers with（R）-（ ＋ ）-α-methylbenzylamine and（S）- phenylalanine methyl ester.
基金Supported by Scientific Research Special Fund for Public Welfare Industry (Meteorology) (GYHY20080620)
文摘The variation characteristics of acid rain and the relationship between the formation of acid rain and meteorological conditions were analyzed based on the observation data and meteorological records collected from acid rain observation station in Dalian over 2006-2009.The results showed that Dalian was one of the regions with strong acid rain in northern China,with the frequency of 66% and pH value of 3.49.The acidity was the strongest in fall and weakest in spring;and the maximum and minimum frequencies were in summer and in winter respectively.Frequency of acid rain was inversely proportional to wind speed and concentration of inhalable particles in Dalian;acid rain occurred easily in foggy weather due to the steady stratification and abundant moisture;continuous precipitation did not mean the reduction of acidic material in the air,and the rainfall with increased acidity in the second day accounted for 42% in continuous precipitation cases.
基金Project(2011SK3262) supported by Science and Technology Program of Hunan Province,China
文摘A two-step leaching method in combination of acid and ethylene diaminetetraacetic acid disodium （EDTA-Na2） was applied to extract metals such as Cd, Cu, Fe, Pb and Zn from a zinc smelting slag. The results show that the extraction rates of Cd, Cu, Fe and Zn in slag reach 88.3%, 54.1%, 69.6% and 54.7%, respectively, while the extraction rate of Pb is only 0.05% leached with 1.25 mol/L sulfuric acid under the conditions of the ratio of slag to liquid of 100 g/L, 65 ℃ and 120 r/min for 2 h. However, Pb extraction rate from 1.25 mol/L sulfuric acid leached residue reaches as high as 66.5% by using 0.1 mol/L EDTA-Na2 solution. The results indicate that two-step sequential extraction procedure combining 1.25 mol/L sulfuric acid and 0.1 mol/L EDTA-Na2 solution can extensively extract Cd, Cu, Fe, Pb and Zn from zinc smelting slag.
基金the National Nature Science Foundation of China,No.39800121
文摘AIM: To identify hepatitis C virus(HCV) core protein epitopes recognized by HLA-A2 restricted cytotoxic T lymphocyte (CTL). METHODS: Utilizing the method of computer prediction followed by a 4h(51)Cr release assay confirmation. RESULTS: The results showed that peripheral blood mononuclear cells (PBMC) obtained from two HLA-A2 positive donors who were infected with HCV could lyse autologous target cells labeled with peptide "ALAHGVRAL (core 150-158)". The rates of specific lysis of the cells from the two donors were 37.5% and 15.8%, respectively. Blocking of the CTL response with anti-CD4 mAb caused no significant decrease of the specific lysis. But blocking of CTL response with anti-CD8 mAb could abolish the lysis. CONCLUSION: The peptide (core 150-158) is the candidate epitope recognized by HLAA2 restricted CTL.
文摘目的评估国家早期预警评分2(NEWS2)联合动脉血乳酸水平预测重症社区获得性肺炎(SCAP)患者短期预后的价值。方法回顾性收集某三甲医院2017年5月—2022年5月收治的成人SCAP住院患者的中性粒细胞与淋巴细胞比值(NLR)、氧合指数、NEWS 2评分及急性生理学与慢性健康状况评分Ⅱ(APACHEⅡ)等资料。根据28天预后分为存活组和死亡组,比较组间差异,并分析主要指标的相关性。采用多因素logistic回归分析和受试者工作特征(ROC)曲线分析NEWS2评分、乳酸以及两者联合对SCAP患者死亡风险的预测价值。结果共入组97例SCAP患者,存活65例,死亡32例,28天病死率32.99%。与存活组比较,死亡组患者入院时NEWS2评分、APACHEⅡ评分、降钙素原(PCT)、NLR及血乳酸均较高,CD3^(+)CD4^(+)T淋巴细胞、氧合指数明显降低,差异均有统计学意义(均P<0.05)。血乳酸与NEWS2评分、APACHEⅡ评分均具有较好的相关性(r值分别为0.411、0.709,均P<0.01)。多因素logistic回归分析显示,NEWS2评分和血乳酸为SCAP患者28天死亡的独立危险因素(OR=1.422,95%CI:1.043~1.938;OR=1.635,95%CI:1.072~2.492,均P<0.05)。ROC曲线分析显示,与传统指标APACHEⅡ评分相比较,NEWS2评分、血乳酸对SCAP患者28天死亡的预测价值良好[曲线下面积(AUC)分别为0.740、0.721 VS 0.772,Z值为0.506、1.141,均P>0.05];当NEWS2评分、血乳酸最佳截断值分别是7分、1.96 mmol/L时,灵敏度分别为81.3%、68.7%,特异度分别为63.1%、75.4%。NEWS2评分联合血乳酸显示出更高的预测价值(AUC为0.776 VS 0.772),并且具有较高的灵敏度(84.4%)和特异度(70.8%)。结论入院时NEWS2评分、血乳酸是SCAP患者28天死亡的独立危险因素,均具有较高的预测价值;NEWS2评分联合血乳酸预测SCAP患者短期预后的价值更高,优于单个评分。
基金supported by the National Natural Science Foundation of China(51321062,21134002)
文摘Synthesis of polyols from carbon dioxide（CO2） is attractive from the viewpoint of sustainable development of polyurethane industry;it is also interesting to adjust the structure of the CO2-polyols for versatile requirement of polyurethane.However,when renewable malonic acid was used as a starter,the copolymerization reaction of CO2 and propylene oxide（PO） was uncontrollable,since it proceeded slowly（13 h） and produced 40.4 wt%of byproduct propylene carbonate（PC） with a low productivity of 0.34kg/g.A careful analysis disclosed that the acid value of the copolymerization medium was the key factor for controlling the copolymerization reaction.Therefore,a preactivation approach was developed to dramatically reduce the acid value to 0.6mg（KOH）/gby homopolymerization of PO into oligo-ether-diol under the initiation of malonic acid,which ensured the controllable copolymerization,where the copolymerization time could be shortened by 77%from 13 to 3 h,the PC content was reduced by 76%from 40.4 wt%to 9.4 wt%,and the productivity increased by 61%from 0.34 to 0.55 kg/g.Moreover,by means of preactivation approach,the molecular weight as well as the carbonate unit content in the CO2-diol was also controllable.
