To extract and display the significant information of combat systems,this paper introduces the methodology of functional cartography into combat networks and proposes an integrated framework named“functional cartogra...To extract and display the significant information of combat systems,this paper introduces the methodology of functional cartography into combat networks and proposes an integrated framework named“functional cartography of heterogeneous combat networks based on the operational chain”(FCBOC).In this framework,a functional module detection algorithm named operational chain-based label propagation algorithm(OCLPA),which considers the cooperation and interactions among combat entities and can thus naturally tackle network heterogeneity,is proposed to identify the functional modules of the network.Then,the nodes and their modules are classified into different roles according to their properties.A case study shows that FCBOC can provide a simplified description of disorderly information of combat networks and enable us to identify their functional and structural network characteristics.The results provide useful information to help commanders make precise and accurate decisions regarding the protection,disintegration or optimization of combat networks.Three algorithms are also compared with OCLPA to show that FCBOC can most effectively find functional modules with practical meaning.展开更多
Fault diagnosis occupies a pivotal position within the domain of machine and equipment management.Existing methods,however,often exhibit limitations in their scope of application,typically focusing on specific types o...Fault diagnosis occupies a pivotal position within the domain of machine and equipment management.Existing methods,however,often exhibit limitations in their scope of application,typically focusing on specific types of signals or faults in individual mechanical components while being constrained by data types and inherent characteristics.To address the limitations of existing methods,we propose a fault diagnosis method based on graph neural networks(GNNs)embedded with multirelationships of intrinsic mode functions(MIMF).The approach introduces a novel graph topological structure constructed from the features of intrinsic mode functions(IMFs)of monitored signals and their multirelationships.Additionally,a graph-level based fault diagnosis network model is designed to enhance feature learning capabilities for graph samples and enable flexible application across diverse signal sources and devices.Experimental validation with datasets including independent vibration signals for gear fault detection,mixed vibration signals for concurrent gear and bearing faults,and pressure signals for hydraulic cylinder leakage characterization demonstrates the model's adaptability and superior diagnostic accuracy across various types of signals and mechanical systems.展开更多
This study aimed to investigate the effect of ultrasound-assisted alkaline extraction(UAE)(at 20 kHz and different powers of 0,200,300,400,500 and 600 W for 10 min)on the yield,structure and emulsifying properties of ...This study aimed to investigate the effect of ultrasound-assisted alkaline extraction(UAE)(at 20 kHz and different powers of 0,200,300,400,500 and 600 W for 10 min)on the yield,structure and emulsifying properties of chickpea protein isolate(CPI).Compared with the non-ultrasound group,ultrasound treatment at 400 W resulted in the largest increase in CPI yield,and both the particle size and turbidity decreased with increasing ultrasound power from 0 to 400 W.The scanning electron microscope results showed a uniform structural distribution of CPI.Moreover,itsα-helix content increased,β-sheet content decreased,and total sulfhydryl group content and endogenous fluorescence intensity rose,illustrating that UAE changed the secondary and tertiary structure of CPI.At 400 W,the solubility of the emulsion increased to 63.18%,and the best emulsifying properties were obtained;the emulsifying activity index(EAI)and emulsifying stability index(ESI)increased by 85.42%and 46.78%,respectively.Furthermore,the emulsion droplets formed were smaller and more uniform.In conclusion,proper UAE power conditions increased the extraction yield and protein content of CPI,and effectively improved its structure and emulsifying characteristics.展开更多
The development of the socialist market economy demands the furtherintensification of the reform of the management operating system (MOS)of the state-owned assets, the strengthening of the efficiency in the man-agemen...The development of the socialist market economy demands the furtherintensification of the reform of the management operating system (MOS)of the state-owned assets, the strengthening of the efficiency in the man-agement of state-owned assets,and the improvement of the operating bene-展开更多
s Western Yunnan is located at the boundary of collision or underthrusting zone of Eurasian plate and is influenced by many times tectonic movements. With very complex geological environment and tectonic background, i...s Western Yunnan is located at the boundary of collision or underthrusting zone of Eurasian plate and is influenced by many times tectonic movements. With very complex geological environment and tectonic background, it is one of the seismically active areas. In the paper, the teleseismic records were selected from 16 national, local and mo-bile stations, including 4 very-wide-band mobile stations of PASSCAL. And nearly 2 000 receiver functions were extracted. Two measuring lines are 650 km and 450 km, respectively and across some major tectonic units in Western Yunnan. It is indicated that Nujiang might be a seam characterized by underthrusting. The western and eastern boundaries of Sichuan-Yunnan rhombus block, i.e., Honghe and Xiaojiang faults, might be an erection seam or collision belt. Panxi tectonic zone still has the characteristics of continental rift valley, that is, the surface is hollow and the upper mantle is upwarping. The tectonic situation in Western Yunnan is of certain regulation with the interlacing distribution of orogenic zone and seam. The crustal thickness decreases gradually from the north to the south and the S wave velocity is globally lower here.展开更多
Various incorporation of Au in pyrite and its effects on the geometrical structure,electronic structure and flotability of pyrite were theoretically investigated and fully discussed by performing density functional th...Various incorporation of Au in pyrite and its effects on the geometrical structure,electronic structure and flotability of pyrite were theoretically investigated and fully discussed by performing density functional theory(DFT).The calculated incorporation energy shows that gold would most likely exist in pyrite via incorporating into interstitial lattice sites in the absence of As impurity.As a result of incorporated Au,the covalence levels of the S—Fe and S—S bonds are changed,and the tonicity of Au—S bonds and antibonding of Au—Fe bonds are found to form in the pyrite,which would change the natural flotability of pyrite.The Au impurity energy levels are introduced into the energy band and result in the transformation of pyrite semiconductivity type.The calculated band-gap value suggests that the incorporated Au significantly decreases pyrite semiconductivity level,which enhances the formation and the adsorption stability of dixanthogen during pyrite flotation.The DOS results reveal that the stability and depression difficulty level of pyrites increases in the following order:Fe_(32)S_(63)As<Fe_(32)S_(64)<Fe_(32)S_(63)As Au<Fe_(32)S_(64)Au.展开更多
The relationship between Solidago canadensis L. invasion and soil microbial community diversity including functional and structure diversities was studied across the invasive gradients varying from 0 to 40%, 80%, and ...The relationship between Solidago canadensis L. invasion and soil microbial community diversity including functional and structure diversities was studied across the invasive gradients varying from 0 to 40%, 80%, and 100% coverage of Solidago canadensis L. using sole carbon source utilization profiles analyses, principle component analysis （PCA） and phospholipid fatty acids （PLFA） profiles analyses. The results show the characteristics of soil microbial community functional and structure diversity in invaded soils strongly changed by Solidago canadensis L. invasion. Solidago canadensis L. invasion tended to result in higher substrate richness, and functional diversity. As compared to the native and ecotones, average utilization of specific substrate guilds of soil microbe was the highest in Solidago canadensis L. monoculture. Soil microbial functional diversity in Solidago canadensis L. monoculture was distinctly separated from the native area and the ecotones. Aerobic bacteria, fungi and actinomycetes population significantly increased but anaerobic bacteria decreased in the soil with Solidago canadensis L. monoculture. The ratio of cyl9：0 to 18：1 co7 gradually declined but mono/sat and fung/bact PLFAs increased when Solidago canadensis L. became more dominant. The microbial community composition clearly separated the native soil from the invaded soils by PCA analysis, especially 18： lco7c, 16： lco7t, 16： lco5c and 18：2co6, 9 were present in higher concentrations for exotic soil. In conclusion, Solidago canadensis L. invasion could create better soil conditions by improving soil microbial community structure and functional diversity, which in turn was more conducive to the growth ofSolidago canadensis L.展开更多
The effect of salt solutions(NaCl,Na2SO4 and CaCl2) on the conformational properties of partially hydrolyzed polyacrylamide(HPAM) was investigated by using static laser light scattering(SLLS).The special interaction b...The effect of salt solutions(NaCl,Na2SO4 and CaCl2) on the conformational properties of partially hydrolyzed polyacrylamide(HPAM) was investigated by using static laser light scattering(SLLS).The special interaction between CaCl2 solution and HPAM was also researched.Experimental results show that the chain structure of HPAM is interrelated with the charge density,the kind and the concentration of salt solutions.The mean-square radius of gyration(Rz) and the second virial coefficient(A2) of HPAM decrease with increasing concentration of salt solutions,and the salt effect tends towards the maximum when the concentration of salt solution is increased to some amount.展开更多
The phase composition, phase transition and phase structure transformation of the wire-cut section of functionally graded WC-Co cemented carbide with dual phase structure were investigated by XRD phase analysis. It is...The phase composition, phase transition and phase structure transformation of the wire-cut section of functionally graded WC-Co cemented carbide with dual phase structure were investigated by XRD phase analysis. It is shown that the composition of η phase in the core zone is Co_3W_3C (M_6 C type). The structure of cobalt based solid solution binder phase is fcc type. At the cooling stage of the sintering process, the phase transition of η phase, i.e. M_6C→M_12C and the martensitic phase transition of the cobalt based solid solution binder phase, i.e. fcc→hcp are suppressed, which facilitates the strengthening of the alloy. Because the instantaneous temperature of the discharge channel is as high as 10 000 ℃ during the wire cutting process, the processed surface is oxidized. Nevertheless, the oxide layer thickness is in micro grade. In the oxide film, η phase is decomposed into W_2C and CoO, and cobalt based solid solution binder is selectively oxidized, while WC remains stable due to the existence of carbon containing liquid organic cutting medium.展开更多
Structural and electronic properties of Pb_(n)Ag_(n)(n=2–12)clusters were investigated by density functional theory with generalized gradient approximation at BLYP level in DMol3 program package.The optimized bimetal...Structural and electronic properties of Pb_(n)Ag_(n)(n=2–12)clusters were investigated by density functional theory with generalized gradient approximation at BLYP level in DMol3 program package.The optimized bimetallic Pb_(n)Ag_(n)(n=2–12)clusters were viewed as the initial structures,then,those were calculated by ab initio molecular dynamics(AIMD)to search possible global minimum energy structures of Pb_(n)Ag_(n)clusters,finally,the ground state structures of Pb_(n)Ag_(n)(n=2–12)clusters were achieved.According to the structural evolution of lowest energy structures,Ag atoms prefer gather in the central sites while Pb atoms prefer external positions in Pb_(n)Ag_(n)(n=2–12)clusters,which is in excellent agreement with experimental results from literature and the application in metallurgy.The average binding energies,HOMO-LUMO gaps,vertical ionization potentials,vertical electron affinities,chemical hardnessη,HOMO orbits,LUMO orbits and density of states of Pb_(n)Ag_(n)(n=2–12)clusters were calculated.The results indicate that the values of HOMO-LUMO gaps,vertical ionization potentials,vertical electron affinities and chemical hardnessηshow obvious odd-even oscillations when n≤5,Pb_(n)Ag_(n)(n=2–12)clusters become less chemically stable and show insulator-to-metal transition with the variation of cluster size n,Pb_(n)Ag_(n)(n≥9)cluster are good candidates to study the properties of PbAg alloys.Those can be well explained by the density of states(DOS)distributions of Pb atoms and Ag atoms between–0.5 Ha and 0.25 Ha in Pb_(n)Ag_(n)(n=2–12)clusters.展开更多
To investigate the effects of aluminum trichloride （AlCl3） on renal structure and function in chickens, the chickens were injected continuously with different gradient AlCl3 for 60 days to establish sub-chronic alum...To investigate the effects of aluminum trichloride （AlCl3） on renal structure and function in chickens, the chickens were injected continuously with different gradient AlCl3 for 60 days to establish sub-chronic aluminum （Al） intoxication model. The AI concentration in serum and kidney, contents of creatinine （Cr） and blood urea nitrogen （BUN） in serum were detected, and the renal structure was also observed by optical microscope. The results showed that the A1 concentration in serum and kidney, the contents of Cr and BUN in serum were significantly higher in Al-treated chickens than those in the control group （P〈0.05; P〈0.01） and there was an AlCl3 dose-depended manner. Histopathologically, in the low dose group, acinus renis swelled mildly and there were no apparent pathological changes in nephric tubule and proximal convoluted tubule. In the middle and high dose group, acinus renis swelled, glomerular cells increased, nephric tubule cloudy swelled, and epithelial cells of proximal convoluted tubule swelled. The results indicated that sub-chronic Al exposure impaired the renal structure and function in chickens.展开更多
Increased circulating branched-chain amino acids(BCAAs)have been involved in the pathogenesis of obesity and insulin resistance.However,evidence relating berberine(BBR),gut microbiota,BCAAs,and insulin resis⁃tance is ...Increased circulating branched-chain amino acids(BCAAs)have been involved in the pathogenesis of obesity and insulin resistance.However,evidence relating berberine(BBR),gut microbiota,BCAAs,and insulin resis⁃tance is limited.Here,we showed that BBR could effectively rectify steatohepatitis and glucose intolerance in high-fat diet(HFD)-fed mice.BBR reorganized gut microbiota populations under both the normal chow diet(NCD)and HFD.Particu⁃larly,BBR noticeably decreased the relative abundance of BCAA-producing bacteria,including order Clostridiales;fami⁃lies Streptococcaceae,Clostridiaceae,and Prevotellaceae;and genera Streptococcus and Prevotella.Compared with the HFD group,predictive metagenomics indicated a reduction in the proportion of gut microbiota genes involved in BCAA biosynthesis but the enrichment genes for BCAA degradation and transport by BBR treatment.Accordingly,the elevated serum BCAAs of HFD group were significantly decreased by BBR.Furthermore,the Western blotting results implied that BBR could promote the BCAA catabolism in the liver and epididymal white adipose tissues of HFD-fed mice by acti⁃vation of the multienzyme branched-chain α-ketoacid dehydrogenase complex,whereas by inhibition of the phosphoryla⁃tion state of BCKDHA(E1α subunit)and branched-chain α-ketoacid dehydrogenase kinase.The ex vivo assay further confirmed that BBR could increase BCAA catabolism in both AML12 hepatocytes and 3T3-L1 adipocytes.Finally,data from healthy subjects and diabetics confirmed that BBR could improve glycemic control and modulate circulating BCAAs.Besides,functional microbiomics integrated high-throughput microbial genomics,metabolomics and molecular biotechnology has also been successfully applied to reveal the anti-obesity mechanism of hydroxysafflor yellow A.展开更多
Cellulose and hemicellulose (mostly xylan), together with lignin, are the major polymeric constituents of plant cell walls and from the largest reservoir of fixed carbon in nature. The enzymatic hydrolysis of polymeri...Cellulose and hemicellulose (mostly xylan), together with lignin, are the major polymeric constituents of plant cell walls and from the largest reservoir of fixed carbon in nature. The enzymatic hydrolysis of polymeric substances by extracellular enzymes, such as cellulases, hemicellulases and laccases, is preferred to chemical depolymerisation to avoid the production of toxic by-products and waste that are expensive to treat. The monosaccharides released through enzymatic hydrolysis can subsequently be microbially converted to commercial commodities, such as bio-ethanol (fuel extender) or microbial protein as feed supplements. The individual depolymerisering enzymes used, such as cellulases, xylanases and laccases, also have industrial application in (i) biobleaching in the paper and pulp industry, (ii) improvement of animal feed (poultry and ruminants) digestibility in feed industries, and (iii) dough rheology and bread volume in the baking process, and beer viscosity and filtration velocity during brewing. The cloning of the genes, coding for several xylan degrading enzymes, and their expression in Baker’s yeast (Saccharomyces cerevisiae) and filamentous fungi (Aspergillus species) opened the possibility to study the pure enzymes, without contaminating activity. Trichoderma reesei produces several of these enzymes and detailed information on their specificity, synergies and structure/activity relationships is known. An overview will be presented.展开更多
文摘To extract and display the significant information of combat systems,this paper introduces the methodology of functional cartography into combat networks and proposes an integrated framework named“functional cartography of heterogeneous combat networks based on the operational chain”(FCBOC).In this framework,a functional module detection algorithm named operational chain-based label propagation algorithm(OCLPA),which considers the cooperation and interactions among combat entities and can thus naturally tackle network heterogeneity,is proposed to identify the functional modules of the network.Then,the nodes and their modules are classified into different roles according to their properties.A case study shows that FCBOC can provide a simplified description of disorderly information of combat networks and enable us to identify their functional and structural network characteristics.The results provide useful information to help commanders make precise and accurate decisions regarding the protection,disintegration or optimization of combat networks.Three algorithms are also compared with OCLPA to show that FCBOC can most effectively find functional modules with practical meaning.
文摘Fault diagnosis occupies a pivotal position within the domain of machine and equipment management.Existing methods,however,often exhibit limitations in their scope of application,typically focusing on specific types of signals or faults in individual mechanical components while being constrained by data types and inherent characteristics.To address the limitations of existing methods,we propose a fault diagnosis method based on graph neural networks(GNNs)embedded with multirelationships of intrinsic mode functions(MIMF).The approach introduces a novel graph topological structure constructed from the features of intrinsic mode functions(IMFs)of monitored signals and their multirelationships.Additionally,a graph-level based fault diagnosis network model is designed to enhance feature learning capabilities for graph samples and enable flexible application across diverse signal sources and devices.Experimental validation with datasets including independent vibration signals for gear fault detection,mixed vibration signals for concurrent gear and bearing faults,and pressure signals for hydraulic cylinder leakage characterization demonstrates the model's adaptability and superior diagnostic accuracy across various types of signals and mechanical systems.
文摘This study aimed to investigate the effect of ultrasound-assisted alkaline extraction(UAE)(at 20 kHz and different powers of 0,200,300,400,500 and 600 W for 10 min)on the yield,structure and emulsifying properties of chickpea protein isolate(CPI).Compared with the non-ultrasound group,ultrasound treatment at 400 W resulted in the largest increase in CPI yield,and both the particle size and turbidity decreased with increasing ultrasound power from 0 to 400 W.The scanning electron microscope results showed a uniform structural distribution of CPI.Moreover,itsα-helix content increased,β-sheet content decreased,and total sulfhydryl group content and endogenous fluorescence intensity rose,illustrating that UAE changed the secondary and tertiary structure of CPI.At 400 W,the solubility of the emulsion increased to 63.18%,and the best emulsifying properties were obtained;the emulsifying activity index(EAI)and emulsifying stability index(ESI)increased by 85.42%and 46.78%,respectively.Furthermore,the emulsion droplets formed were smaller and more uniform.In conclusion,proper UAE power conditions increased the extraction yield and protein content of CPI,and effectively improved its structure and emulsifying characteristics.
文摘The development of the socialist market economy demands the furtherintensification of the reform of the management operating system (MOS)of the state-owned assets, the strengthening of the efficiency in the man-agement of state-owned assets,and the improvement of the operating bene-
基金State Key Basic Research Development and Programming Project of China (G1998040700).
文摘s Western Yunnan is located at the boundary of collision or underthrusting zone of Eurasian plate and is influenced by many times tectonic movements. With very complex geological environment and tectonic background, it is one of the seismically active areas. In the paper, the teleseismic records were selected from 16 national, local and mo-bile stations, including 4 very-wide-band mobile stations of PASSCAL. And nearly 2 000 receiver functions were extracted. Two measuring lines are 650 km and 450 km, respectively and across some major tectonic units in Western Yunnan. It is indicated that Nujiang might be a seam characterized by underthrusting. The western and eastern boundaries of Sichuan-Yunnan rhombus block, i.e., Honghe and Xiaojiang faults, might be an erection seam or collision belt. Panxi tectonic zone still has the characteristics of continental rift valley, that is, the surface is hollow and the upper mantle is upwarping. The tectonic situation in Western Yunnan is of certain regulation with the interlacing distribution of orogenic zone and seam. The crustal thickness decreases gradually from the north to the south and the S wave velocity is globally lower here.
基金Projects(51504109,51504107)supported by the National Natural Science Foundation of China
文摘Various incorporation of Au in pyrite and its effects on the geometrical structure,electronic structure and flotability of pyrite were theoretically investigated and fully discussed by performing density functional theory(DFT).The calculated incorporation energy shows that gold would most likely exist in pyrite via incorporating into interstitial lattice sites in the absence of As impurity.As a result of incorporated Au,the covalence levels of the S—Fe and S—S bonds are changed,and the tonicity of Au—S bonds and antibonding of Au—Fe bonds are found to form in the pyrite,which would change the natural flotability of pyrite.The Au impurity energy levels are introduced into the energy band and result in the transformation of pyrite semiconductivity type.The calculated band-gap value suggests that the incorporated Au significantly decreases pyrite semiconductivity level,which enhances the formation and the adsorption stability of dixanthogen during pyrite flotation.The DOS results reveal that the stability and depression difficulty level of pyrites increases in the following order:Fe_(32)S_(63)As<Fe_(32)S_(64)<Fe_(32)S_(63)As Au<Fe_(32)S_(64)Au.
基金Project(2009QNA6015) supported by the Fundamental Research Funds for the Central Universities of ChinaProject(Y3110055)supported by the Natural Science Foundation of Zhejiang Province,ChinaProject(Y200803219) supported by the Foundation of Zhejiang Educational Committee of China
文摘The relationship between Solidago canadensis L. invasion and soil microbial community diversity including functional and structure diversities was studied across the invasive gradients varying from 0 to 40%, 80%, and 100% coverage of Solidago canadensis L. using sole carbon source utilization profiles analyses, principle component analysis （PCA） and phospholipid fatty acids （PLFA） profiles analyses. The results show the characteristics of soil microbial community functional and structure diversity in invaded soils strongly changed by Solidago canadensis L. invasion. Solidago canadensis L. invasion tended to result in higher substrate richness, and functional diversity. As compared to the native and ecotones, average utilization of specific substrate guilds of soil microbe was the highest in Solidago canadensis L. monoculture. Soil microbial functional diversity in Solidago canadensis L. monoculture was distinctly separated from the native area and the ecotones. Aerobic bacteria, fungi and actinomycetes population significantly increased but anaerobic bacteria decreased in the soil with Solidago canadensis L. monoculture. The ratio of cyl9：0 to 18：1 co7 gradually declined but mono/sat and fung/bact PLFAs increased when Solidago canadensis L. became more dominant. The microbial community composition clearly separated the native soil from the invaded soils by PCA analysis, especially 18： lco7c, 16： lco7t, 16： lco5c and 18：2co6, 9 were present in higher concentrations for exotic soil. In conclusion, Solidago canadensis L. invasion could create better soil conditions by improving soil microbial community structure and functional diversity, which in turn was more conducive to the growth ofSolidago canadensis L.
基金Project(50673033) supported by the National Natural Science Foundation of China
文摘The effect of salt solutions(NaCl,Na2SO4 and CaCl2) on the conformational properties of partially hydrolyzed polyacrylamide(HPAM) was investigated by using static laser light scattering(SLLS).The special interaction between CaCl2 solution and HPAM was also researched.Experimental results show that the chain structure of HPAM is interrelated with the charge density,the kind and the concentration of salt solutions.The mean-square radius of gyration(Rz) and the second virial coefficient(A2) of HPAM decrease with increasing concentration of salt solutions,and the salt effect tends towards the maximum when the concentration of salt solution is increased to some amount.
基金Projects(50323008, 50574104) supported by the National Natural Science Foundation of ChinaProject (04JJ3084) supported by the Natural Science Foundation of Hunan Province, China
文摘The phase composition, phase transition and phase structure transformation of the wire-cut section of functionally graded WC-Co cemented carbide with dual phase structure were investigated by XRD phase analysis. It is shown that the composition of η phase in the core zone is Co_3W_3C (M_6 C type). The structure of cobalt based solid solution binder phase is fcc type. At the cooling stage of the sintering process, the phase transition of η phase, i.e. M_6C→M_12C and the martensitic phase transition of the cobalt based solid solution binder phase, i.e. fcc→hcp are suppressed, which facilitates the strengthening of the alloy. Because the instantaneous temperature of the discharge channel is as high as 10 000 ℃ during the wire cutting process, the processed surface is oxidized. Nevertheless, the oxide layer thickness is in micro grade. In the oxide film, η phase is decomposed into W_2C and CoO, and cobalt based solid solution binder is selectively oxidized, while WC remains stable due to the existence of carbon containing liquid organic cutting medium.
基金Project(51664032)supported by the Regional Foundation of the National Natural Science Foundation of ChinaProject(51474116)supported by the General Program of the National Natural Science Foundation of China+5 种基金Project(U1502271)supported by the Joint Foundation of the NSFC-Yunnan Province,ChinaProject(2014HA003)supported by the Cultivating Plan Program for the Leader in Science and Technology of Yunnan Province,ChinaProject(2014RA4018)supported by the Program for Nonferrous Metals Vacuum Metallurgy Innovation Team of Ministry of Science and Technology,ChinaProject(2016YFC0400404)supported by the National Key Research and Development Program of ChinaProject(51504115)supported by the Youth Program of National Natural Science Foundation of ChinaProject(IRT_17R48)supported by the Program for Innovative Research Team in University of Ministry of Education of China
文摘Structural and electronic properties of Pb_(n)Ag_(n)(n=2–12)clusters were investigated by density functional theory with generalized gradient approximation at BLYP level in DMol3 program package.The optimized bimetallic Pb_(n)Ag_(n)(n=2–12)clusters were viewed as the initial structures,then,those were calculated by ab initio molecular dynamics(AIMD)to search possible global minimum energy structures of Pb_(n)Ag_(n)clusters,finally,the ground state structures of Pb_(n)Ag_(n)(n=2–12)clusters were achieved.According to the structural evolution of lowest energy structures,Ag atoms prefer gather in the central sites while Pb atoms prefer external positions in Pb_(n)Ag_(n)(n=2–12)clusters,which is in excellent agreement with experimental results from literature and the application in metallurgy.The average binding energies,HOMO-LUMO gaps,vertical ionization potentials,vertical electron affinities,chemical hardnessη,HOMO orbits,LUMO orbits and density of states of Pb_(n)Ag_(n)(n=2–12)clusters were calculated.The results indicate that the values of HOMO-LUMO gaps,vertical ionization potentials,vertical electron affinities and chemical hardnessηshow obvious odd-even oscillations when n≤5,Pb_(n)Ag_(n)(n=2–12)clusters become less chemically stable and show insulator-to-metal transition with the variation of cluster size n,Pb_(n)Ag_(n)(n≥9)cluster are good candidates to study the properties of PbAg alloys.Those can be well explained by the density of states(DOS)distributions of Pb atoms and Ag atoms between–0.5 Ha and 0.25 Ha in Pb_(n)Ag_(n)(n=2–12)clusters.
基金Supported by the National Natural Science Foundation of China (31172375)
文摘To investigate the effects of aluminum trichloride （AlCl3） on renal structure and function in chickens, the chickens were injected continuously with different gradient AlCl3 for 60 days to establish sub-chronic aluminum （Al） intoxication model. The AI concentration in serum and kidney, contents of creatinine （Cr） and blood urea nitrogen （BUN） in serum were detected, and the renal structure was also observed by optical microscope. The results showed that the A1 concentration in serum and kidney, the contents of Cr and BUN in serum were significantly higher in Al-treated chickens than those in the control group （P〈0.05; P〈0.01） and there was an AlCl3 dose-depended manner. Histopathologically, in the low dose group, acinus renis swelled mildly and there were no apparent pathological changes in nephric tubule and proximal convoluted tubule. In the middle and high dose group, acinus renis swelled, glomerular cells increased, nephric tubule cloudy swelled, and epithelial cells of proximal convoluted tubule swelled. The results indicated that sub-chronic Al exposure impaired the renal structure and function in chickens.
文摘Increased circulating branched-chain amino acids(BCAAs)have been involved in the pathogenesis of obesity and insulin resistance.However,evidence relating berberine(BBR),gut microbiota,BCAAs,and insulin resis⁃tance is limited.Here,we showed that BBR could effectively rectify steatohepatitis and glucose intolerance in high-fat diet(HFD)-fed mice.BBR reorganized gut microbiota populations under both the normal chow diet(NCD)and HFD.Particu⁃larly,BBR noticeably decreased the relative abundance of BCAA-producing bacteria,including order Clostridiales;fami⁃lies Streptococcaceae,Clostridiaceae,and Prevotellaceae;and genera Streptococcus and Prevotella.Compared with the HFD group,predictive metagenomics indicated a reduction in the proportion of gut microbiota genes involved in BCAA biosynthesis but the enrichment genes for BCAA degradation and transport by BBR treatment.Accordingly,the elevated serum BCAAs of HFD group were significantly decreased by BBR.Furthermore,the Western blotting results implied that BBR could promote the BCAA catabolism in the liver and epididymal white adipose tissues of HFD-fed mice by acti⁃vation of the multienzyme branched-chain α-ketoacid dehydrogenase complex,whereas by inhibition of the phosphoryla⁃tion state of BCKDHA(E1α subunit)and branched-chain α-ketoacid dehydrogenase kinase.The ex vivo assay further confirmed that BBR could increase BCAA catabolism in both AML12 hepatocytes and 3T3-L1 adipocytes.Finally,data from healthy subjects and diabetics confirmed that BBR could improve glycemic control and modulate circulating BCAAs.Besides,functional microbiomics integrated high-throughput microbial genomics,metabolomics and molecular biotechnology has also been successfully applied to reveal the anti-obesity mechanism of hydroxysafflor yellow A.
文摘Cellulose and hemicellulose (mostly xylan), together with lignin, are the major polymeric constituents of plant cell walls and from the largest reservoir of fixed carbon in nature. The enzymatic hydrolysis of polymeric substances by extracellular enzymes, such as cellulases, hemicellulases and laccases, is preferred to chemical depolymerisation to avoid the production of toxic by-products and waste that are expensive to treat. The monosaccharides released through enzymatic hydrolysis can subsequently be microbially converted to commercial commodities, such as bio-ethanol (fuel extender) or microbial protein as feed supplements. The individual depolymerisering enzymes used, such as cellulases, xylanases and laccases, also have industrial application in (i) biobleaching in the paper and pulp industry, (ii) improvement of animal feed (poultry and ruminants) digestibility in feed industries, and (iii) dough rheology and bread volume in the baking process, and beer viscosity and filtration velocity during brewing. The cloning of the genes, coding for several xylan degrading enzymes, and their expression in Baker’s yeast (Saccharomyces cerevisiae) and filamentous fungi (Aspergillus species) opened the possibility to study the pure enzymes, without contaminating activity. Trichoderma reesei produces several of these enzymes and detailed information on their specificity, synergies and structure/activity relationships is known. An overview will be presented.
