目的观察BAPTA-AM对胞外酸化诱导大鼠关节软骨细胞自噬作用的影响,探讨其可能的作用机制。方法体外使用胰酶-Ⅱ型胶原酶消化法分离提取大鼠关节软骨细胞,分为正常组(p H 7.4)、酸化组(p H 6.0)、以及分别经BAPTA-AM处理的正常组和酸化组...目的观察BAPTA-AM对胞外酸化诱导大鼠关节软骨细胞自噬作用的影响,探讨其可能的作用机制。方法体外使用胰酶-Ⅱ型胶原酶消化法分离提取大鼠关节软骨细胞,分为正常组(p H 7.4)、酸化组(p H 6.0)、以及分别经BAPTA-AM处理的正常组和酸化组,激光共聚焦技术检测软骨细胞胞内钙离子变化,实时荧光定量PCR法检测细胞自噬基因Beclin-1、ULK1 mRNA的表达,Western blot法检测自噬蛋白LC3的表达,吖啶橙染色分析细胞自噬溶酶体形成情况。结果与p H 7.4正常组比较,p H 6.0酸化刺激明显增加大鼠关节软骨细胞内Ca2+的浓度,且自噬标志物Beclin-1、ULK1 mRNA及LC3Ⅱ蛋白表达均明显升高,酸性自噬溶酶体形成增多,同时酸化刺激能引起Ca MKKβ及pAMPK蛋白表达水平增高,磷酸化蛋白p-m TOR水平明显降低。BAPTA-AM酸化组自噬水平和Ca MKKβ及p-AMPK表达明显降低,p-m TOR表达明显升高。结论 BAPTA-AM能明显减弱胞外酸化诱导软骨细胞自噬作用,其机制可能与抑制胞内Ca2+有关。展开更多
Red-mud is the residue from the Bayer process, in which the iron minerals should be removed before red-mud is used to produce refractory materials. The iron minerals in red-mud were extracted by oxalic acid solution. ...Red-mud is the residue from the Bayer process, in which the iron minerals should be removed before red-mud is used to produce refractory materials. The iron minerals in red-mud were extracted by oxalic acid solution. The content of Fe （calculated in Fe203） in red-mud was reduced from 17.6% to less than 1% after being treated by 1 mol/L oxalic acid solution at 75 ℃ for 2 h. The Fe（Ⅲ） oxalate solution obtained was then irradiated by UV light, resulting in the precipitation of Fe（Ⅱ） oxalate. Under UV photocatalysis, more than 90% of Fe（Ⅲ） oxalate in the extracted solution was transformed into the precipitation of Fe（Ⅱ） oxalate crystallite （fl-FeC2O4·2H2O）. The filtrate from the Fe（Ⅱ） oxalate precipitate filtration could be reused in the next cycle. The mechanism ofUV photocatalysis precipitation was also discussed.展开更多
It is necessary to clarify the influence of thermal history on the conversion of aluminate species in sodium aluminate solution in order to optimize Bayer alumina production. The interconversion of various solution sp...It is necessary to clarify the influence of thermal history on the conversion of aluminate species in sodium aluminate solution in order to optimize Bayer alumina production. The interconversion of various solution species in the systems was investigated by measuring the infrared spectra of sodium aluminate solution with different compositions after separate heat treatment, dilution and concentration. The results show that increasing temperature or prolonging holding time favors the transformation of Al2O（OH）2- to Al—OH vibration（condensed Al O4 tetrahedral aluminate ion） at about 880 cm-1 and Al（OH）-4. A12O（OH）2-66 and Al—OH tetrahedral dimer ions convert rapidly to Al（OH）-4 during the dilution process; however, the back transformation of Al（OH）-4 to the Al—OH tetrahedral dimer ions can occur in diluted sodium aluminate solution. As for the concentration process, the transformation of Al（OH）-4 to A12O（OH）2-6 and Al—OH tetrahedral dimer ions can take place, while it is relatively difficult to transform to A12O（OH）2-6.展开更多
TiO2-coated activated carbon surface （TAs） composites were prepared by a sol-gel method with supercritical pretreatment. The photocatalytic degradation of acid yellow （AY） was investigated under UV radiation to es...TiO2-coated activated carbon surface （TAs） composites were prepared by a sol-gel method with supercritical pretreatment. The photocatalytic degradation of acid yellow （AY） was investigated under UV radiation to estimate activity of catalysts and determine the kinetics. And the effects of parameters including the initial concentration of AY, light intensity and TiO2 content in catalysts were examined. The results indicate that TAs has a higher efficiency in decomposition of AY than P25, pure TiO2 particles as well as the mixture of TiO2 powder and active carbon. The photocatalytic degradation rate is found to follow the pseudo-first order kinetics with respect to the AY concentration. The new kinetic model fairly resembles the classic Langmuir-Hinshelwood equation, and the rate constant is proportional to the square root of the light intensity in a wide range. However, its absorption performance depends on the surface areas of catalysts. The model fits quite well with the experimental data and elucidates phenomena about the effects of the TiO2 content in TAs on the degradation rate.展开更多
Extracellular polymeric substances （EPS） produced by acidophilic bioleaching microorganisms play an important role in the production of acid mine drainage and metal sulfide bioleaching. EPS mediate the contact betwe...Extracellular polymeric substances （EPS） produced by acidophilic bioleaching microorganisms play an important role in the production of acid mine drainage and metal sulfide bioleaching. EPS mediate the contact between microbial cells and growth substrates, having a pivotal role in organic film formation and bacterium-substratum interactions. The production and chemical composition of EPS produced by seven bioleaching strains grown with different substrates were studied. Analysis of the EPS extracted from these strains indicated that the EPS consisted of carbohydrates, proteins and galacturonic acid. The contents of EPS, carbohydrates, proteins and galacturonic acid of EPS were largely related to the kind of strain used and culture condition. The results show that EPS productions of microbes grown with pyrite were significantly higher than those of microbes grown with sulfur or FeSO4·7H2O. The highest EPS production of the seven acidiphilic strains was （159.43±3.93） mg/g, which was produced by Leptospirillum ferriphilum CBCBSUCSU208015 when cultivated with pyrite.展开更多
Aim To strdy the separation of native amino acids using capillary zone electro- pboresis (CZE) with indirect ultraviolet detecition. Methods 13 native amino acids were sepa- rated by capillary electrophoresis with ind...Aim To strdy the separation of native amino acids using capillary zone electro- pboresis (CZE) with indirect ultraviolet detecition. Methods 13 native amino acids were sepa- rated by capillary electrophoresis with indirect detection . The experiments were carried out with homemade CE apparatus under the following operating conditior conditions: a fused-silica capillary col- umn of 50.0cm effect length and of 75m i.d. was used. 7 organic acids were used as BGAE, and a positive potential of separation in CZE with indirect detection. After optimizing for l3 native amino acids were established. Conclusion The choice of BGAe is an important factor influencing the efficiency of separation in CZE with indiect detection .After optimizing the separation conditions a baseline separation for 13 native amino acids is obtained.展开更多
The effect of pH values on the extracellular protein and polysaccharide secretions of Acidithiobacillus ferrooxidans was comparatively investigated in different phases of bacterial growth during chalcopyrite bioleachi...The effect of pH values on the extracellular protein and polysaccharide secretions of Acidithiobacillus ferrooxidans was comparatively investigated in different phases of bacterial growth during chalcopyrite bioleaching. The results indicate that the extracellular protein is always more than the extracellular polysaccharide secreted by attached cells on the chalcopyrite, on the contrary, and is always less than the extracellular polysaccharide secreted by free cells in the solution at bacterial adaptive phase, logarithmic phase and stationary phase whenever pH value is at 1.0, 1.5, 2.0 or 2.5; free cells are mainly through the secretion of extracellular polysaccharide rather than the extracellular protein to fight against disadvantageous solution environment, such as high concentration of metal ions and unsuitable pH solution; both amounts of polysaccharide and protein secreted by attached cells are mainly positively related to the solution acidity rather than the total concentration of soluble metal ions. The experimental results imply that bacteria are mainly through secreting more extracellular polysaccharide to fight against disadvantageous environment and the extracellular protein perhaps plays an important role in oxidation？reduction reactions in the bioleaching system.展开更多
To address the environmental and health hazards of nitrate(NO_(3)^(-))in water,a denitrification advanced reduction process(ARP)using only formic acid(HCOOH)activated by ultraviolet(UV)light was proposed.The efficienc...To address the environmental and health hazards of nitrate(NO_(3)^(-))in water,a denitrification advanced reduction process(ARP)using only formic acid(HCOOH)activated by ultraviolet(UV)light was proposed.The efficiency,influencing factors,mechanism,and kinetics of the reduction were investigated through component analysis and radical detection.Results show that,after 90 min of UV illumination,the reduction and gas conversion ratios of 50 mg/L NO_(3)^(-)-N reach 99.9%and 99.8%,respectively,under 9 mM of C_(0)(HCOOH),pH=3.0,and N_(2) aeration.Meanwhile,96.7%of HCOOH is consumed and converted into gas.The NO_(3)^(-)-N conversion process includes the transformation to NO_(2)^(-)-N,followed by a further reduction to gas and a direct conversion into gas,introducing small amounts of nitrite and ammonia.The carbon dioxide anion radical(·CO_(2)^(-))from HCOOH/HCOO^(-)is the principal cause of NO_(3)^(-)-N reduction by UV/HCOOH/N 2 ARP.In contrast,·CO_(2)^(-)production is caused by the hydroxyl radical(·OH).The NO_(3)^(-)-N reduction efficiency is enhanced by the increase in the light intensity,considerably affected by the initial pH,and less affected by inorganic anions,including Cl^(-),H_(2)PO_(4)^(-),and HCO_(3)^(-)/CO_(3)^(2-).The initial HCOOH concentration and light intensity are the main factors that influence the NO_(3)^(-)-N reduction rate.展开更多
Objective] This study aimed to eliminate the negative effects brought about by continuous, long-term accumulation of sodium ions in soil on soil environ-ment. [Method] Biological humic acids （BHAs） were extracted fr...Objective] This study aimed to eliminate the negative effects brought about by continuous, long-term accumulation of sodium ions in soil on soil environ-ment. [Method] Biological humic acids （BHAs） were extracted from fermented furfural residue via alkali-dissolution and acidification. The effects of solid-liquid ratio （mass ratio of fermented furfural residue to water）, alkali concentration, extraction tempera-ture and extraction time on the content of BHA were investigated. Also its structure was characterized by FTIR. [Result] The optimal extraction conditions were as fol-lows： solid-liquid ratio of 1：7, KOH concentration of 6%, extraction temperature of 70℃ and extraction time of 1 h. Under the optimal conditions, the content of BHAs extracted was up to 8.5%. The infrared spectrum analysis indicated that BHA had more types of functional groups and lower molecular weight than commercial humic acid although they had similar structures. [Conclusion] The technique has the ad-vantages of simple operation and good stability, and is suitable for extracting BHAs. BHAs have a good prospect in developing new types of humic acid fertilizers.展开更多
Two kinds of UV curable polyurethane acrylate oligomers （PUPA and PUCA） were synthesized via the addition reaction between isophorone diisocyanate （IPDI） and polyethylene glycol monoacrylate （PEA6） or polycaprol...Two kinds of UV curable polyurethane acrylate oligomers （PUPA and PUCA） were synthesized via the addition reaction between isophorone diisocyanate （IPDI） and polyethylene glycol monoacrylate （PEA6） or polycaprolactone modified hydroxyethyl acrylate （PCLA2）. The structures of PUPA and PUCA were characterized by Fourier transform infrared spectroscopy （FT-IR）, IH nuclear magnetic resonance （^H NMR）, gel permeation chromatography （GPC） and differential scanning calorimeter （DSC）, and the thermal stability and dynamic mechanical thermal properties of their cured films were measured by thermogravimetric analysis （TGA） and dynamic mechanical analysis （DMA）, respectively. The viscosity of the oligomers and mechanical properties of the cured films were also studied. The results show that both oligomers have narrow molecular weight distribution. The viscosity of PUPA is 2.310 Pa.s at 25 ℃, while that of PUCA is： up to 3.980 Pa-s. The UV cured PUPA and PUCA films have homogeneous phase structure, and the PUCA film shows higher glass transition temperature and storage modulus. Furthermore, the PUCA film possesses better mechanical properties than PUPA, while the latter shows better alkali resistance.展开更多
This paper introduces the discovery,composition and structure of oxalate oxidase,as well as illustrates the biological functions of this enzyme.With a comprehensive introduction upon previous researches upon gene clon...This paper introduces the discovery,composition and structure of oxalate oxidase,as well as illustrates the biological functions of this enzyme.With a comprehensive introduction upon previous researches upon gene cloning and heredity transformation of this enzyme,it indicates that heredity transformation can increase the content of oxalate oxidase within the plants and also enhance their resistance.The paper also points out the problems such as lack of gene resources and difficulty in the transformation of heterologous genes,and the focus in later researches should be laid upon the exploration of plant resources relative to this enzyme and selection of resistant species.展开更多
文摘目的观察BAPTA-AM对胞外酸化诱导大鼠关节软骨细胞自噬作用的影响,探讨其可能的作用机制。方法体外使用胰酶-Ⅱ型胶原酶消化法分离提取大鼠关节软骨细胞,分为正常组(p H 7.4)、酸化组(p H 6.0)、以及分别经BAPTA-AM处理的正常组和酸化组,激光共聚焦技术检测软骨细胞胞内钙离子变化,实时荧光定量PCR法检测细胞自噬基因Beclin-1、ULK1 mRNA的表达,Western blot法检测自噬蛋白LC3的表达,吖啶橙染色分析细胞自噬溶酶体形成情况。结果与p H 7.4正常组比较,p H 6.0酸化刺激明显增加大鼠关节软骨细胞内Ca2+的浓度,且自噬标志物Beclin-1、ULK1 mRNA及LC3Ⅱ蛋白表达均明显升高,酸性自噬溶酶体形成增多,同时酸化刺激能引起Ca MKKβ及pAMPK蛋白表达水平增高,磷酸化蛋白p-m TOR水平明显降低。BAPTA-AM酸化组自噬水平和Ca MKKβ及p-AMPK表达明显降低,p-m TOR表达明显升高。结论 BAPTA-AM能明显减弱胞外酸化诱导软骨细胞自噬作用,其机制可能与抑制胞内Ca2+有关。
基金Project (2010AA101703) supported by the National Hi-tech Research and Development Program of China
文摘Red-mud is the residue from the Bayer process, in which the iron minerals should be removed before red-mud is used to produce refractory materials. The iron minerals in red-mud were extracted by oxalic acid solution. The content of Fe （calculated in Fe203） in red-mud was reduced from 17.6% to less than 1% after being treated by 1 mol/L oxalic acid solution at 75 ℃ for 2 h. The Fe（Ⅲ） oxalate solution obtained was then irradiated by UV light, resulting in the precipitation of Fe（Ⅱ） oxalate. Under UV photocatalysis, more than 90% of Fe（Ⅲ） oxalate in the extracted solution was transformed into the precipitation of Fe（Ⅱ） oxalate crystallite （fl-FeC2O4·2H2O）. The filtrate from the Fe（Ⅱ） oxalate precipitate filtration could be reused in the next cycle. The mechanism ofUV photocatalysis precipitation was also discussed.
基金Project(51274243)supported by the National Natural Science Foundation of China
文摘It is necessary to clarify the influence of thermal history on the conversion of aluminate species in sodium aluminate solution in order to optimize Bayer alumina production. The interconversion of various solution species in the systems was investigated by measuring the infrared spectra of sodium aluminate solution with different compositions after separate heat treatment, dilution and concentration. The results show that increasing temperature or prolonging holding time favors the transformation of Al2O（OH）2- to Al—OH vibration（condensed Al O4 tetrahedral aluminate ion） at about 880 cm-1 and Al（OH）-4. A12O（OH）2-66 and Al—OH tetrahedral dimer ions convert rapidly to Al（OH）-4 during the dilution process; however, the back transformation of Al（OH）-4 to the Al—OH tetrahedral dimer ions can occur in diluted sodium aluminate solution. As for the concentration process, the transformation of Al（OH）-4 to A12O（OH）2-6 and Al—OH tetrahedral dimer ions can take place, while it is relatively difficult to transform to A12O（OH）2-6.
基金Project(50802034) supported by the National Natural Science Foundation of ChinaProject(11A093) supported by the Key Project Foundation by the Education Department of Hunan Province,China
文摘TiO2-coated activated carbon surface （TAs） composites were prepared by a sol-gel method with supercritical pretreatment. The photocatalytic degradation of acid yellow （AY） was investigated under UV radiation to estimate activity of catalysts and determine the kinetics. And the effects of parameters including the initial concentration of AY, light intensity and TiO2 content in catalysts were examined. The results indicate that TAs has a higher efficiency in decomposition of AY than P25, pure TiO2 particles as well as the mixture of TiO2 powder and active carbon. The photocatalytic degradation rate is found to follow the pseudo-first order kinetics with respect to the AY concentration. The new kinetic model fairly resembles the classic Langmuir-Hinshelwood equation, and the rate constant is proportional to the square root of the light intensity in a wide range. However, its absorption performance depends on the surface areas of catalysts. The model fits quite well with the experimental data and elucidates phenomena about the effects of the TiO2 content in TAs on the degradation rate.
文摘Extracellular polymeric substances （EPS） produced by acidophilic bioleaching microorganisms play an important role in the production of acid mine drainage and metal sulfide bioleaching. EPS mediate the contact between microbial cells and growth substrates, having a pivotal role in organic film formation and bacterium-substratum interactions. The production and chemical composition of EPS produced by seven bioleaching strains grown with different substrates were studied. Analysis of the EPS extracted from these strains indicated that the EPS consisted of carbohydrates, proteins and galacturonic acid. The contents of EPS, carbohydrates, proteins and galacturonic acid of EPS were largely related to the kind of strain used and culture condition. The results show that EPS productions of microbes grown with pyrite were significantly higher than those of microbes grown with sulfur or FeSO4·7H2O. The highest EPS production of the seven acidiphilic strains was （159.43±3.93） mg/g, which was produced by Leptospirillum ferriphilum CBCBSUCSU208015 when cultivated with pyrite.
文摘Aim To strdy the separation of native amino acids using capillary zone electro- pboresis (CZE) with indirect ultraviolet detecition. Methods 13 native amino acids were sepa- rated by capillary electrophoresis with indirect detection . The experiments were carried out with homemade CE apparatus under the following operating conditior conditions: a fused-silica capillary col- umn of 50.0cm effect length and of 75m i.d. was used. 7 organic acids were used as BGAE, and a positive potential of separation in CZE with indirect detection. After optimizing for l3 native amino acids were established. Conclusion The choice of BGAe is an important factor influencing the efficiency of separation in CZE with indiect detection .After optimizing the separation conditions a baseline separation for 13 native amino acids is obtained.
基金Project(31200382)supported by the National Natural Science Foundation of China
文摘The effect of pH values on the extracellular protein and polysaccharide secretions of Acidithiobacillus ferrooxidans was comparatively investigated in different phases of bacterial growth during chalcopyrite bioleaching. The results indicate that the extracellular protein is always more than the extracellular polysaccharide secreted by attached cells on the chalcopyrite, on the contrary, and is always less than the extracellular polysaccharide secreted by free cells in the solution at bacterial adaptive phase, logarithmic phase and stationary phase whenever pH value is at 1.0, 1.5, 2.0 or 2.5; free cells are mainly through the secretion of extracellular polysaccharide rather than the extracellular protein to fight against disadvantageous solution environment, such as high concentration of metal ions and unsuitable pH solution; both amounts of polysaccharide and protein secreted by attached cells are mainly positively related to the solution acidity rather than the total concentration of soluble metal ions. The experimental results imply that bacteria are mainly through secreting more extracellular polysaccharide to fight against disadvantageous environment and the extracellular protein perhaps plays an important role in oxidation？reduction reactions in the bioleaching system.
基金The National Major Science and Technology Project(No.2017ZX07202-004-005)。
文摘To address the environmental and health hazards of nitrate(NO_(3)^(-))in water,a denitrification advanced reduction process(ARP)using only formic acid(HCOOH)activated by ultraviolet(UV)light was proposed.The efficiency,influencing factors,mechanism,and kinetics of the reduction were investigated through component analysis and radical detection.Results show that,after 90 min of UV illumination,the reduction and gas conversion ratios of 50 mg/L NO_(3)^(-)-N reach 99.9%and 99.8%,respectively,under 9 mM of C_(0)(HCOOH),pH=3.0,and N_(2) aeration.Meanwhile,96.7%of HCOOH is consumed and converted into gas.The NO_(3)^(-)-N conversion process includes the transformation to NO_(2)^(-)-N,followed by a further reduction to gas and a direct conversion into gas,introducing small amounts of nitrite and ammonia.The carbon dioxide anion radical(·CO_(2)^(-))from HCOOH/HCOO^(-)is the principal cause of NO_(3)^(-)-N reduction by UV/HCOOH/N 2 ARP.In contrast,·CO_(2)^(-)production is caused by the hydroxyl radical(·OH).The NO_(3)^(-)-N reduction efficiency is enhanced by the increase in the light intensity,considerably affected by the initial pH,and less affected by inorganic anions,including Cl^(-),H_(2)PO_(4)^(-),and HCO_(3)^(-)/CO_(3)^(2-).The initial HCOOH concentration and light intensity are the main factors that influence the NO_(3)^(-)-N reduction rate.
文摘Objective] This study aimed to eliminate the negative effects brought about by continuous, long-term accumulation of sodium ions in soil on soil environ-ment. [Method] Biological humic acids （BHAs） were extracted from fermented furfural residue via alkali-dissolution and acidification. The effects of solid-liquid ratio （mass ratio of fermented furfural residue to water）, alkali concentration, extraction tempera-ture and extraction time on the content of BHA were investigated. Also its structure was characterized by FTIR. [Result] The optimal extraction conditions were as fol-lows： solid-liquid ratio of 1：7, KOH concentration of 6%, extraction temperature of 70℃ and extraction time of 1 h. Under the optimal conditions, the content of BHAs extracted was up to 8.5%. The infrared spectrum analysis indicated that BHA had more types of functional groups and lower molecular weight than commercial humic acid although they had similar structures. [Conclusion] The technique has the ad-vantages of simple operation and good stability, and is suitable for extracting BHAs. BHAs have a good prospect in developing new types of humic acid fertilizers.
基金Project(2007168303) supported by Guangdong-Hong Kong Technology Cooperation Funding
文摘Two kinds of UV curable polyurethane acrylate oligomers （PUPA and PUCA） were synthesized via the addition reaction between isophorone diisocyanate （IPDI） and polyethylene glycol monoacrylate （PEA6） or polycaprolactone modified hydroxyethyl acrylate （PCLA2）. The structures of PUPA and PUCA were characterized by Fourier transform infrared spectroscopy （FT-IR）, IH nuclear magnetic resonance （^H NMR）, gel permeation chromatography （GPC） and differential scanning calorimeter （DSC）, and the thermal stability and dynamic mechanical thermal properties of their cured films were measured by thermogravimetric analysis （TGA） and dynamic mechanical analysis （DMA）, respectively. The viscosity of the oligomers and mechanical properties of the cured films were also studied. The results show that both oligomers have narrow molecular weight distribution. The viscosity of PUPA is 2.310 Pa.s at 25 ℃, while that of PUCA is： up to 3.980 Pa-s. The UV cured PUPA and PUCA films have homogeneous phase structure, and the PUCA film shows higher glass transition temperature and storage modulus. Furthermore, the PUCA film possesses better mechanical properties than PUPA, while the latter shows better alkali resistance.
基金Supported by Jilin Province Post-doctoral Project"Exploration of Quality Bean Sclerotiniose-tolerant Seeds and Genetic Resources"(00206)
文摘This paper introduces the discovery,composition and structure of oxalate oxidase,as well as illustrates the biological functions of this enzyme.With a comprehensive introduction upon previous researches upon gene cloning and heredity transformation of this enzyme,it indicates that heredity transformation can increase the content of oxalate oxidase within the plants and also enhance their resistance.The paper also points out the problems such as lack of gene resources and difficulty in the transformation of heterologous genes,and the focus in later researches should be laid upon the exploration of plant resources relative to this enzyme and selection of resistant species.
