单个裂隙是构成裂隙网络的基础,其中的水流和溶质运移机理目前尚未完全清楚。文章使用平行大理石板构成单裂隙试验模型,研究了水力梯度和流速之间的关系以及溶质运移规律,采用连续时间随机游走(continuous time random walk,CTRW)模拟...单个裂隙是构成裂隙网络的基础,其中的水流和溶质运移机理目前尚未完全清楚。文章使用平行大理石板构成单裂隙试验模型,研究了水力梯度和流速之间的关系以及溶质运移规律,采用连续时间随机游走(continuous time random walk,CTRW)模拟软件包中的截断幂函数(truncation power-law function,TPL)对溶质的穿透曲线进行模拟,并与传统的对流-弥散方程(advection-dispersion equation,ADE)模拟结果进行了对比,探讨了CTRW中参数的变化特征。结果表明:实验条件下的水流呈非达西流,用Forchheimer方程能更好地拟合裂隙中水力梯度和流速的关系;裂隙内的溶质运移为非费克运移,表现出明显的“拖尾”现象;在实验条件下拟合溶质运移的穿透曲线,TPL的拟合结果均明显优于ADE;同一隙宽下,模型参数β随流速的增加而增加,其值分别为0.882、1.045、1.375;同一流速下,β随隙宽的增加而减小,其值分别为1.375、1.263、1.112。展开更多
Objective: To evaluate the expression of DNA plasmid-harboring modified antibody gene that produces neutralizing human monoclonal antibodies against four serotypes of dengue virus(DENV) without enhancing activity in B...Objective: To evaluate the expression of DNA plasmid-harboring modified antibody gene that produces neutralizing human monoclonal antibodies against four serotypes of dengue virus(DENV) without enhancing activity in BALB/c mice. Methods: We constructed pFUSE-based vectors(pFUSE1 G7 C2hVH and pFUSE1 G7 C2hVL) containing genes encoding the variable domains of the heavy or light chain of the anti-dengue virus antibody 1 G7 C2, a human IgG1 that has been characterized for its neutralizing activity to DENV-1-4. Leucine(L) at positions 234 and 235 on the Fc CH2 domain in pFUSE1 G7 C2hVH was mutated to alanine(A)(LALA mutation) by site direct mutagenesis, and the new plasmid was termed pFUSE1 G7 C2hVHLALA. An equal amount of pFUSE1 G7 C2hVL and 1 G7 C2hG1-LALA plasmids were co-transfected into Chinese hamster ovary cells(CHO-K1) and a single dose of 100 μg 1 G7 C2hG1-LALA plasmid was intramuscularly injected, followed by electroporation in BALB/c mice. The secreted 1 G7 C2hG1-LALA antibodies in cell culture supernatant and mouse serum were examined for their biological functions, neutralization and enhancing activity. Results: The co-transfection of heavy-and light-chain 1 G7 C2hG1-LALA plasmids in CHO-K1 cells produced approximately 3 900 ng/mL human IgG and neutralized 90%-100% all four DENV, with no enhancing activity. Furthermore, the modified human IgG was produced more than 1 000 ng/mL in mouse serum on day 7 post plasmid injection and showed cross-neutralization to four DENV serotypes. Subsequently, antibody production and neutralization decreased rapidly. Nevertheless, the secreted neutralizing 1 G7 C2hG1-LALA in mouse serum demonstrated complete absence of enhancing activities to all DENV serotypes. Conclusions: These findings reveal that a new modified 1 G7 C2h G1-LALA expressing plasmid based on gene transfer is a possible therapeutic antibody candidate against DENV infection.展开更多
Explicit solution techniques have been widely used in geotechnical engineering for simulating the coupled hydro-mechanical(H-M) interaction of fluid flow and deformation induced by structures built above and under sat...Explicit solution techniques have been widely used in geotechnical engineering for simulating the coupled hydro-mechanical(H-M) interaction of fluid flow and deformation induced by structures built above and under saturated ground, i.e. circular footing and deep tunnel. However, the technique is only conditionally stable and requires small time steps, portending its inefficiency for simulating large-scale H-M problems. To improve its efficiency, the unconditionally stable alternating direction explicit(ADE)scheme could be used to solve the flow problem. The standard ADE scheme, however, is only moderately accurate and is restricted to uniform grids and plane strain flow conditions. This paper aims to remove these drawbacks by developing a novel high-order ADE scheme capable of solving flow problems in nonuniform grids and under axisymmetric conditions. The new scheme is derived by performing a fourthorder finite difference(FD) approximation to the spatial derivatives of the axisymmetric fluid-diffusion equation in a non-uniform grid configuration. The implicit Crank-Nicolson technique is then applied to the resulting approximation, and the subsequent equation is split into two alternating direction sweeps,giving rise to a new axisymmetric ADE scheme. The pore pressure solutions from the new scheme are then sequentially coupled with an existing geomechanical simulator in the computer code fast Lagrangian analysis of continua(FLAC). This coupling procedure is called the sequentially-explicit coupling technique based on the fourth-order axisymmetric ADE scheme or SEA-4-AXI. Application of SEA-4-AXI for solving axisymmetric consolidation of a circular footing and of advancing tunnel in deep saturated ground shows that SEA-4-AXI reduces computer runtime up to 42%-50% that of FLAC’s basic scheme without numerical instability. In addition, it produces high numerical accuracy of the H-M solutions with average percentage difference of only 0.5%-1.8%.展开更多
A set of novel graph-theoretical parameters, called the atomic distance-edge (ADE) vector, was developed. Baaed on the connecting C-C bond number between central carbon atom and the other ones, various carbon atoms of...A set of novel graph-theoretical parameters, called the atomic distance-edge (ADE) vector, was developed. Baaed on the connecting C-C bond number between central carbon atom and the other ones, various carbon atoms of alkanes were classified as four types, i.e., type 1, 2, 3 and 4 for primary, secondary, ternary and quaternary carbon, respectively; and then four regression equations were obtained to link carbon-13 chemical shift (CS) of each type of atoms. Furthermore, these regression models were used to predict the carbon-13 nuclear magnetic resonance spectra of alkanes and it was found that the estimated CS were in agreement with the experimental results.展开更多
Porcine reproductive and respiratory syndrome(PRRS)is one of the most significant diseases affecting the pig industry worldwide.The PRRSV mutation rate is the highest among the RNA viruses.To date,NADC30-like PRRSV an...Porcine reproductive and respiratory syndrome(PRRS)is one of the most significant diseases affecting the pig industry worldwide.The PRRSV mutation rate is the highest among the RNA viruses.To date,NADC30-like PRRSV and highly pathogenic PRRSV(HP-PRRSV)are the dominant epidemic strains in China;however,commercial vaccines do not always provide sufficient cross-protection,and the reasons for insufficient protection are unclear.This study isolated a wild-type NADC30-like PRRSV,SX-YL1806,from Shaanxi Province.Vaccination challenge experiments in piglets showed that commercial modified live virus(MLV)vaccines provided good protection against HP-PRRSV.However,it could not provide sufficient protection against the novel strain SXYL1806.To explore the reasons for this phenomenon,we compared the genomic homology between the MLV strain and HP-PRRSV or NADC30-like PRRSV and found that the MLV strain had a lower genome similarity with NADC30-like PRRSV.Serum neutralization assay showed that MLV-immune serum slightly promoted the homologous HP-PRRSV replication and significantly promoted the heterologous NADC30-like PRRSV strain replication in vitro,suggesting that antibody-dependent enhancement(ADE)might also play a role in decreasing MLV protective efficacy.These findings expand our understanding of the potential factors affecting the protective effect of PRRSV MLV vaccines against the NADC30-like strains.展开更多
Currently there is no effective antiviral therapy for SARS-CoV-2 infection, which frequently leads to fatal inflammatory responses and acute lung injury. Here, we discuss the various mechanisms of SARS-CoV-mediated in...Currently there is no effective antiviral therapy for SARS-CoV-2 infection, which frequently leads to fatal inflammatory responses and acute lung injury. Here, we discuss the various mechanisms of SARS-CoV-mediated inflammation. We also assume that SARS-CoV-2 likely shares similar inflammatory responses. Potential therapeutic tools to reduce SARS-CoV-2-induced inflammatory responses include various methods to block FcR activation. In the absence of a proven clinical FcR blocker, the use of intravenous immunoglobulin to block FcR activation may be a viable option for the urgent treatment of pulmonary inflammation to prevent severe lung injury. Such treatment may also be combined with systemic anti-inflammatory drugs or corticosteroids. However, these strategies, as proposed here, remain to be clinically tested for effectiveness.展开更多
This article summarizes the recent progress of nutrient removal from wastewater via microalgae.Removal of nitrogen and phosphorous compounds from wastewater are of great importance,while those compounds are suitable f...This article summarizes the recent progress of nutrient removal from wastewater via microalgae.Removal of nitrogen and phosphorous compounds from wastewater are of great importance,while those compounds are suitable for growth of some microalgae species.Such a combination provides more opportunities for anaerobic digestion facilities,which are producing large amount of wastewater with high nitrogen and phosphorous contents.However,in order to optimize and maximize the performance and durability of the nutrient removal process,it is suggested that the basic principles about nitrogen and phosphorous migration should be investigated thoroughly,especially from the fundamentals of substance transfer mechanism between water environment and algal cells.展开更多
文摘单个裂隙是构成裂隙网络的基础,其中的水流和溶质运移机理目前尚未完全清楚。文章使用平行大理石板构成单裂隙试验模型,研究了水力梯度和流速之间的关系以及溶质运移规律,采用连续时间随机游走(continuous time random walk,CTRW)模拟软件包中的截断幂函数(truncation power-law function,TPL)对溶质的穿透曲线进行模拟,并与传统的对流-弥散方程(advection-dispersion equation,ADE)模拟结果进行了对比,探讨了CTRW中参数的变化特征。结果表明:实验条件下的水流呈非达西流,用Forchheimer方程能更好地拟合裂隙中水力梯度和流速的关系;裂隙内的溶质运移为非费克运移,表现出明显的“拖尾”现象;在实验条件下拟合溶质运移的穿透曲线,TPL的拟合结果均明显优于ADE;同一隙宽下,模型参数β随流速的增加而增加,其值分别为0.882、1.045、1.375;同一流速下,β随隙宽的增加而减小,其值分别为1.375、1.263、1.112。
基金supported by the Faculty of Tropical Medicine,Mahidol University,Thailand,Research Fund through a Research and Researcher for Industry(RRi,Grant Number PHD59I0063 for SB)TRF Grant for New Researcher(TRG,Grant Number TRG5980015 for CP)the Office of the National Research Council of Thailand-Japan Society for the Promotion of Science(JSPS)or NRCT-JSPS
文摘Objective: To evaluate the expression of DNA plasmid-harboring modified antibody gene that produces neutralizing human monoclonal antibodies against four serotypes of dengue virus(DENV) without enhancing activity in BALB/c mice. Methods: We constructed pFUSE-based vectors(pFUSE1 G7 C2hVH and pFUSE1 G7 C2hVL) containing genes encoding the variable domains of the heavy or light chain of the anti-dengue virus antibody 1 G7 C2, a human IgG1 that has been characterized for its neutralizing activity to DENV-1-4. Leucine(L) at positions 234 and 235 on the Fc CH2 domain in pFUSE1 G7 C2hVH was mutated to alanine(A)(LALA mutation) by site direct mutagenesis, and the new plasmid was termed pFUSE1 G7 C2hVHLALA. An equal amount of pFUSE1 G7 C2hVL and 1 G7 C2hG1-LALA plasmids were co-transfected into Chinese hamster ovary cells(CHO-K1) and a single dose of 100 μg 1 G7 C2hG1-LALA plasmid was intramuscularly injected, followed by electroporation in BALB/c mice. The secreted 1 G7 C2hG1-LALA antibodies in cell culture supernatant and mouse serum were examined for their biological functions, neutralization and enhancing activity. Results: The co-transfection of heavy-and light-chain 1 G7 C2hG1-LALA plasmids in CHO-K1 cells produced approximately 3 900 ng/mL human IgG and neutralized 90%-100% all four DENV, with no enhancing activity. Furthermore, the modified human IgG was produced more than 1 000 ng/mL in mouse serum on day 7 post plasmid injection and showed cross-neutralization to four DENV serotypes. Subsequently, antibody production and neutralization decreased rapidly. Nevertheless, the secreted neutralizing 1 G7 C2hG1-LALA in mouse serum demonstrated complete absence of enhancing activities to all DENV serotypes. Conclusions: These findings reveal that a new modified 1 G7 C2h G1-LALA expressing plasmid based on gene transfer is a possible therapeutic antibody candidate against DENV infection.
基金the support from the University Transportation Center for Underground Transportation Infrastructure at the Colorado School of Mines for partially funding this research under Grant No. 69A3551747118 of the Fixing America's Surface Transportation Act (FAST Act) of U.S. DoT FY2016
文摘Explicit solution techniques have been widely used in geotechnical engineering for simulating the coupled hydro-mechanical(H-M) interaction of fluid flow and deformation induced by structures built above and under saturated ground, i.e. circular footing and deep tunnel. However, the technique is only conditionally stable and requires small time steps, portending its inefficiency for simulating large-scale H-M problems. To improve its efficiency, the unconditionally stable alternating direction explicit(ADE)scheme could be used to solve the flow problem. The standard ADE scheme, however, is only moderately accurate and is restricted to uniform grids and plane strain flow conditions. This paper aims to remove these drawbacks by developing a novel high-order ADE scheme capable of solving flow problems in nonuniform grids and under axisymmetric conditions. The new scheme is derived by performing a fourthorder finite difference(FD) approximation to the spatial derivatives of the axisymmetric fluid-diffusion equation in a non-uniform grid configuration. The implicit Crank-Nicolson technique is then applied to the resulting approximation, and the subsequent equation is split into two alternating direction sweeps,giving rise to a new axisymmetric ADE scheme. The pore pressure solutions from the new scheme are then sequentially coupled with an existing geomechanical simulator in the computer code fast Lagrangian analysis of continua(FLAC). This coupling procedure is called the sequentially-explicit coupling technique based on the fourth-order axisymmetric ADE scheme or SEA-4-AXI. Application of SEA-4-AXI for solving axisymmetric consolidation of a circular footing and of advancing tunnel in deep saturated ground shows that SEA-4-AXI reduces computer runtime up to 42%-50% that of FLAC’s basic scheme without numerical instability. In addition, it produces high numerical accuracy of the H-M solutions with average percentage difference of only 0.5%-1.8%.
文摘A set of novel graph-theoretical parameters, called the atomic distance-edge (ADE) vector, was developed. Baaed on the connecting C-C bond number between central carbon atom and the other ones, various carbon atoms of alkanes were classified as four types, i.e., type 1, 2, 3 and 4 for primary, secondary, ternary and quaternary carbon, respectively; and then four regression equations were obtained to link carbon-13 chemical shift (CS) of each type of atoms. Furthermore, these regression models were used to predict the carbon-13 nuclear magnetic resonance spectra of alkanes and it was found that the estimated CS were in agreement with the experimental results.
基金This research was supported by the National Natural Science Foundation of China(32172846)the Earmarked Fund for CARS-35,the Science and Technology Major Project of Gansu Province(22ZD6NA001)+4 种基金the Science Foundation for Distinguished Young Scholars of Shaanxi Province(2021JC-18)the Natural Science Foundation of Gansu Province(23JRRA1153)the Science and Technology Plan Project of Gansu Province(23JRRA561)the Chinese Academy of Agricultural Science and Technology Innovation Project(CAAS-ASTIP-JBGS-20210602)the Strategic Priority Research Program of the National Center of Technology Innovation for Pigs(NCTIP-XD/C03).
文摘Porcine reproductive and respiratory syndrome(PRRS)is one of the most significant diseases affecting the pig industry worldwide.The PRRSV mutation rate is the highest among the RNA viruses.To date,NADC30-like PRRSV and highly pathogenic PRRSV(HP-PRRSV)are the dominant epidemic strains in China;however,commercial vaccines do not always provide sufficient cross-protection,and the reasons for insufficient protection are unclear.This study isolated a wild-type NADC30-like PRRSV,SX-YL1806,from Shaanxi Province.Vaccination challenge experiments in piglets showed that commercial modified live virus(MLV)vaccines provided good protection against HP-PRRSV.However,it could not provide sufficient protection against the novel strain SXYL1806.To explore the reasons for this phenomenon,we compared the genomic homology between the MLV strain and HP-PRRSV or NADC30-like PRRSV and found that the MLV strain had a lower genome similarity with NADC30-like PRRSV.Serum neutralization assay showed that MLV-immune serum slightly promoted the homologous HP-PRRSV replication and significantly promoted the heterologous NADC30-like PRRSV strain replication in vitro,suggesting that antibody-dependent enhancement(ADE)might also play a role in decreasing MLV protective efficacy.These findings expand our understanding of the potential factors affecting the protective effect of PRRSV MLV vaccines against the NADC30-like strains.
文摘Currently there is no effective antiviral therapy for SARS-CoV-2 infection, which frequently leads to fatal inflammatory responses and acute lung injury. Here, we discuss the various mechanisms of SARS-CoV-mediated inflammation. We also assume that SARS-CoV-2 likely shares similar inflammatory responses. Potential therapeutic tools to reduce SARS-CoV-2-induced inflammatory responses include various methods to block FcR activation. In the absence of a proven clinical FcR blocker, the use of intravenous immunoglobulin to block FcR activation may be a viable option for the urgent treatment of pulmonary inflammation to prevent severe lung injury. Such treatment may also be combined with systemic anti-inflammatory drugs or corticosteroids. However, these strategies, as proposed here, remain to be clinically tested for effectiveness.
基金supported by Chinese National 13th five-year Plan for Key R&D Projects(2018YFD0400804)the Beijing Municipal Education Commission General Project(KM201810011002)+4 种基金the Research Foundation for Youth Scholars of Beijing Technology and Business University(PXM2018_014213_000033)the research was also supported by the National Natural Science Foundation of China(Grant No.51806242)the National Natural Science Foundation of China(No.71961024)the Chinese Universities Scientific Fund(No.2019TC010)the Chinese Universities Scientific Fund-Special Project of“Agricultural Mechanization and Equipment Engineering”for“Double First-Class”Initiative of College of Engineering,China Agricultural University.
文摘This article summarizes the recent progress of nutrient removal from wastewater via microalgae.Removal of nitrogen and phosphorous compounds from wastewater are of great importance,while those compounds are suitable for growth of some microalgae species.Such a combination provides more opportunities for anaerobic digestion facilities,which are producing large amount of wastewater with high nitrogen and phosphorous contents.However,in order to optimize and maximize the performance and durability of the nutrient removal process,it is suggested that the basic principles about nitrogen and phosphorous migration should be investigated thoroughly,especially from the fundamentals of substance transfer mechanism between water environment and algal cells.
