A Discrete Element Method （DEM） model is developed to study the particle break- age effect on the one-dimensional compression behavior of silica sands. The ＇maximum tensile stress＇ breakage criterion considering m...A Discrete Element Method （DEM） model is developed to study the particle break- age effect on the one-dimensional compression behavior of silica sands. The ＇maximum tensile stress＇ breakage criterion considering multiple contacts is adopted to simulate the crushing of circular particles in the DEM. The model is compared with published experimental results. Com- parison between the compression curves obtained from the numerical and experimental results shows that the proposed method is very effective in studying the compression behavior of silica sands considering particle breakage. The evolution of compression curves at different stress levels is extensively studied using contact force distribution, variation of contact number and particle size distribution curve with loading. It is found that particle breakage has great impact on com- pression behavior of sand, particularly after the yield stress is reached and particle breakage starts. The crushing probability of particles is found to be macroscopically affected by stress level and particle size distribution curve, and microscopically related to the evolutions of contact force and coordination number. Once the soil becomes well-graded and the average coordination number is greater than 4 in two-dimension, the crushing probability of parent particles can reduce by up to 5/6. It is found that the average contact force does not always increase with loading, but increases to a peak value then decreases once the soil becomes more well-graded. It is found through the loading rate sensitivity analysis that the compression behavior of sand samples in the DEM is also affected by the loading rate. Higher yield stresses are obtained at higher loading rates.展开更多
The distribution of residual stresses through thickness of 5 mm-thick ME21 magnesium alloy extruded plates was analyzed non-destructively using short-wavelength X-ray diffraction(SWXRD),and the effect of homogenizatio...The distribution of residual stresses through thickness of 5 mm-thick ME21 magnesium alloy extruded plates was analyzed non-destructively using short-wavelength X-ray diffraction(SWXRD),and the effect of homogenization annealing before extrusion on the residual stress was discussed.The classic d 0 method with an annealed stress-free reference specimen was employed to determine the residual stress of the extruded plates.The residual stress results showed that the gradient of residual stress in the transverse direction was larger than that of the extrusion direction.The homogenization process prior to extrusion weaken the formed sample’s texture.The maximum residual stress of the as-extruded plate was reduced,and the residual stress distribution was homogenized.展开更多
Arbuscular mycorrhizal(AM)fungi may help protect plants against herbivores;however,their use for the pest control of woody plants requires further study.Here,we investigated the effect of Glomus mosseae colonization o...Arbuscular mycorrhizal(AM)fungi may help protect plants against herbivores;however,their use for the pest control of woody plants requires further study.Here,we investigated the effect of Glomus mosseae colonization on the interactions between gypsy moth larvae and Populus alba×P.berolinensis seedlings and deciphered the regulatory mechanisms underlying the mycorrhizal-induced resistance in the leaves of mycorrhizal poplar using RNA-seq and nontargeted metabolomics.The resistance assay showed that AM fungus inoculation protected poplar seedlings against gypsy moth larvae,as evidenced by the decreased larval growth and reduced larval survival.A transcriptome analysis revealed that differentially expressed genes(DEGs)were involved in jasmonic acid biosynthesis(lipoxygenase,hydroperoxide dehydratase,and allene oxide cyclase)and signal transduction(jasmonate-ZIM domain and transcription factor MYC2)and identified the genes that were upregulated in mycorrhizal seedlings.Except for chalcone synthase and anthocyanidin synthase,which were downregulated in mycorrhizal seedlings,all DEGs related to flavonoid biosynthesis were upregulated,including 4-coumarate-CoA ligase,chalcone isomerase,flavanone 3-hydroxylase,flavonol synthase,and leucoanthocyanidin reductase.The metabolome analysis showed that several metabolites with insecticidal properties,including coumarin,stachydrine,artocarpin,norizalpinin,abietic acid,6-formylumbelliferone,and vanillic acid,were significantly accumulated in the mycorrhizal seedlings.These findings suggest the potential of mycorrhiza-induced resistance for use in pest management of woody plants and demonstrate that the priming of JA-dependent responses in poplar seedlings contributes to mycorrhiza-induced resistance to insect pests.展开更多
Background:A novel coronavirus called severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),first identified in Wuhan,China,has been rapidly spreading around the world.This study investigates the epidemiological...Background:A novel coronavirus called severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),first identified in Wuhan,China,has been rapidly spreading around the world.This study investigates the epidemiological and clinical characteristics of coronavirus disease 2019(COVID-19)patients in Zhejiang Province who did or did not have a history of Wuhan exposure.Methods:We collected data from medical records of confirmed COVID-19 patients in Zhejiang Province from Jan.17 to Feb.7,2020 and analyzed epidemiological,clinical,and treatment data of those with and without recorded recent exposure in Wuhan.Results:Patients in the control group were older than those in the exposure group((48.19±16.13)years vs.(43.47±13.12)years,P<0.001),and more were over 65 years old(15.95%control vs.5.60%exposure,P<0.001).The rate of clustered onset was also significantly higher in the control group than in the exposure group(31.39%vs.18.66%,P<0.001).The symptom of a sore throat in patients in the exposure group was significantly higher than that in the control group(17.30%vs.10.89%,P=0.01);however,headache in the exposure group was significantly lower than that in the control group(6.87%vs.12.15%,P=0.015).More patients in the exposure group had a significantly lower level of lactate dehydrogenase(LDH)and aspartate aminotransferase(AST)than those in the control group.There was no significant difference in any degree of COVID-19 including mild,severe,and critical between the two groups.Conclusions:From the perspective of epidemiological and clinical characteristics,there was no significant difference between COVID-19 patients with and without Wuhan exposure history.展开更多
In this paper, we investigate the empirical likelihood diagnosis of modal linear regression models. The empirical likelihood ratio function based on modal regression estimation method for the regression coefficient is...In this paper, we investigate the empirical likelihood diagnosis of modal linear regression models. The empirical likelihood ratio function based on modal regression estimation method for the regression coefficient is introduced. First, the estimation equation based on empirical likelihood method is established. Then, some diagnostic statistics are proposed. At last, we also examine the performance of proposed method for finite sample sizes through simulation study.展开更多
BACKGROUND Primary biliary cholangitis(PBC)is a chronic autoimmune-mediated cholestatic liver disease.Nanoparticles encapsulating rapamycin(ImmTOR)suppress adaptive immune responses and induce the hepatic tolerogenic ...BACKGROUND Primary biliary cholangitis(PBC)is a chronic autoimmune-mediated cholestatic liver disease.Nanoparticles encapsulating rapamycin(ImmTOR)suppress adaptive immune responses and induce the hepatic tolerogenic immune response.AIM To investigate the effects of ImmTOR in PBC mouse models.METHODS PBC models were induced in C57BL/6 mice by two immunizations of 2-octynoic acid-coupled bovine serum albumin at two-week intervals,and polycytidylic acid every three days.The PBC mouse models were separated into the treatment group and the control group.The levels of alkaline phosphatase(ALP)and alanine aminotransferase in the mice were detected using an automatic biochemical analyzer.Liver and spleen mononuclear cells were analyzed by flow cytometry,and serum anti-mitochondrial antibodies(AMA)and the related cytokines were analyzed by enzyme-linked immunosorbent assay.Liver histopathology was examined by hematoxylin and eosin staining and scored.RESULTS After treatment with ImmTOR,the ALP level was significantly decreased(189.60 U/L±27.25 U/L vs 156.00 U/L±17.21 U/L,P<0.05),the level of AMA was reduced(1.28 ng/mL±0.27 ng/mL vs 0.56 ng/mL±0.07 ng/mL,P<0.001)and the expression levels of interferon gamma and tumor necrosis factorαwere significantly decreased(48.29 pg/mL±10.84 pg/mL vs 25.01 pg/mL±1.49 pg/mL,P<0.0001)and(84.24 pg/mL±23.47 pg/mL vs 40.66 pg/mL±14.65 pg/mL,P<0.001).The CD4+T lymphocytes,CD8+T lymphocytes and B lymphocytes in the liver were significantly reduced,with statistically significant differences(24.21%±6.55%vs 15.98%±3.03%,P<0.05;9.09%±1.91%vs 5.49%±1.00%,P<0.001;80.51%±2.96%vs 75.31%±4.34%,P<0.05).The expression of CD8+T lymphocytes and B lymphocytes in the ImmTOR treatment group also decreased(9.09%±1.91%vs 5.49%±1.00%,P<0.001;80.51%±2.96%vs 75.31%±4.34%,P<0.05).The liver pathology of PBC mice in the treatment group showed reduced inflammation and a decreased total pathology score,and the difference in the scores was statistically significant(4.50±2.88 vs 1.75±1.28,P<0.05).CONCLUSION ImmTOR can improve biochemistry and pathology of liver obvious by inhibiting the expression of CD8+T cells and B cells,and reducing the titer of AMA.展开更多
基金Project supported by the National Natural Science Foundation of China(Nos.50909057,51208294 and 41372319)the Innovation Program of Shanghai Municipal Education Commission(No.15ZZ081)the Innovation Project of Shanghai Postgraduate Education(No.20131129)
文摘A Discrete Element Method （DEM） model is developed to study the particle break- age effect on the one-dimensional compression behavior of silica sands. The ＇maximum tensile stress＇ breakage criterion considering multiple contacts is adopted to simulate the crushing of circular particles in the DEM. The model is compared with published experimental results. Com- parison between the compression curves obtained from the numerical and experimental results shows that the proposed method is very effective in studying the compression behavior of silica sands considering particle breakage. The evolution of compression curves at different stress levels is extensively studied using contact force distribution, variation of contact number and particle size distribution curve with loading. It is found that particle breakage has great impact on com- pression behavior of sand, particularly after the yield stress is reached and particle breakage starts. The crushing probability of particles is found to be macroscopically affected by stress level and particle size distribution curve, and microscopically related to the evolutions of contact force and coordination number. Once the soil becomes well-graded and the average coordination number is greater than 4 in two-dimension, the crushing probability of parent particles can reduce by up to 5/6. It is found that the average contact force does not always increase with loading, but increases to a peak value then decreases once the soil becomes more well-graded. It is found through the loading rate sensitivity analysis that the compression behavior of sand samples in the DEM is also affected by the loading rate. Higher yield stresses are obtained at higher loading rates.
基金This work is supported by the National Key R&D Plan(grant No.2016YFB0301105)the Fundamental Research Funds for the Central Universities(grant No.FRF-TP-16-016A1).
文摘The distribution of residual stresses through thickness of 5 mm-thick ME21 magnesium alloy extruded plates was analyzed non-destructively using short-wavelength X-ray diffraction(SWXRD),and the effect of homogenization annealing before extrusion on the residual stress was discussed.The classic d 0 method with an annealed stress-free reference specimen was employed to determine the residual stress of the extruded plates.The residual stress results showed that the gradient of residual stress in the transverse direction was larger than that of the extrusion direction.The homogenization process prior to extrusion weaken the formed sample’s texture.The maximum residual stress of the as-extruded plate was reduced,and the residual stress distribution was homogenized.
基金This research was supported by the National Key Research and Development Program of China(2018YFC1200400).
文摘Arbuscular mycorrhizal(AM)fungi may help protect plants against herbivores;however,their use for the pest control of woody plants requires further study.Here,we investigated the effect of Glomus mosseae colonization on the interactions between gypsy moth larvae and Populus alba×P.berolinensis seedlings and deciphered the regulatory mechanisms underlying the mycorrhizal-induced resistance in the leaves of mycorrhizal poplar using RNA-seq and nontargeted metabolomics.The resistance assay showed that AM fungus inoculation protected poplar seedlings against gypsy moth larvae,as evidenced by the decreased larval growth and reduced larval survival.A transcriptome analysis revealed that differentially expressed genes(DEGs)were involved in jasmonic acid biosynthesis(lipoxygenase,hydroperoxide dehydratase,and allene oxide cyclase)and signal transduction(jasmonate-ZIM domain and transcription factor MYC2)and identified the genes that were upregulated in mycorrhizal seedlings.Except for chalcone synthase and anthocyanidin synthase,which were downregulated in mycorrhizal seedlings,all DEGs related to flavonoid biosynthesis were upregulated,including 4-coumarate-CoA ligase,chalcone isomerase,flavanone 3-hydroxylase,flavonol synthase,and leucoanthocyanidin reductase.The metabolome analysis showed that several metabolites with insecticidal properties,including coumarin,stachydrine,artocarpin,norizalpinin,abietic acid,6-formylumbelliferone,and vanillic acid,were significantly accumulated in the mycorrhizal seedlings.These findings suggest the potential of mycorrhiza-induced resistance for use in pest management of woody plants and demonstrate that the priming of JA-dependent responses in poplar seedlings contributes to mycorrhiza-induced resistance to insect pests.
基金the National Major Science and Technology Research Projects for the Control and Prevention of Major Infectious Diseases in China(No.2017ZX10202202)the National Natural Science Foundation of China(No.81770574)。
文摘Background:A novel coronavirus called severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),first identified in Wuhan,China,has been rapidly spreading around the world.This study investigates the epidemiological and clinical characteristics of coronavirus disease 2019(COVID-19)patients in Zhejiang Province who did or did not have a history of Wuhan exposure.Methods:We collected data from medical records of confirmed COVID-19 patients in Zhejiang Province from Jan.17 to Feb.7,2020 and analyzed epidemiological,clinical,and treatment data of those with and without recorded recent exposure in Wuhan.Results:Patients in the control group were older than those in the exposure group((48.19±16.13)years vs.(43.47±13.12)years,P<0.001),and more were over 65 years old(15.95%control vs.5.60%exposure,P<0.001).The rate of clustered onset was also significantly higher in the control group than in the exposure group(31.39%vs.18.66%,P<0.001).The symptom of a sore throat in patients in the exposure group was significantly higher than that in the control group(17.30%vs.10.89%,P=0.01);however,headache in the exposure group was significantly lower than that in the control group(6.87%vs.12.15%,P=0.015).More patients in the exposure group had a significantly lower level of lactate dehydrogenase(LDH)and aspartate aminotransferase(AST)than those in the control group.There was no significant difference in any degree of COVID-19 including mild,severe,and critical between the two groups.Conclusions:From the perspective of epidemiological and clinical characteristics,there was no significant difference between COVID-19 patients with and without Wuhan exposure history.
文摘In this paper, we investigate the empirical likelihood diagnosis of modal linear regression models. The empirical likelihood ratio function based on modal regression estimation method for the regression coefficient is introduced. First, the estimation equation based on empirical likelihood method is established. Then, some diagnostic statistics are proposed. At last, we also examine the performance of proposed method for finite sample sizes through simulation study.
基金Supported by Cultivation Project of Hebei Natural Science Foundation-Precision Medicine Joint Fund,No.H2021206239.
文摘BACKGROUND Primary biliary cholangitis(PBC)is a chronic autoimmune-mediated cholestatic liver disease.Nanoparticles encapsulating rapamycin(ImmTOR)suppress adaptive immune responses and induce the hepatic tolerogenic immune response.AIM To investigate the effects of ImmTOR in PBC mouse models.METHODS PBC models were induced in C57BL/6 mice by two immunizations of 2-octynoic acid-coupled bovine serum albumin at two-week intervals,and polycytidylic acid every three days.The PBC mouse models were separated into the treatment group and the control group.The levels of alkaline phosphatase(ALP)and alanine aminotransferase in the mice were detected using an automatic biochemical analyzer.Liver and spleen mononuclear cells were analyzed by flow cytometry,and serum anti-mitochondrial antibodies(AMA)and the related cytokines were analyzed by enzyme-linked immunosorbent assay.Liver histopathology was examined by hematoxylin and eosin staining and scored.RESULTS After treatment with ImmTOR,the ALP level was significantly decreased(189.60 U/L±27.25 U/L vs 156.00 U/L±17.21 U/L,P<0.05),the level of AMA was reduced(1.28 ng/mL±0.27 ng/mL vs 0.56 ng/mL±0.07 ng/mL,P<0.001)and the expression levels of interferon gamma and tumor necrosis factorαwere significantly decreased(48.29 pg/mL±10.84 pg/mL vs 25.01 pg/mL±1.49 pg/mL,P<0.0001)and(84.24 pg/mL±23.47 pg/mL vs 40.66 pg/mL±14.65 pg/mL,P<0.001).The CD4+T lymphocytes,CD8+T lymphocytes and B lymphocytes in the liver were significantly reduced,with statistically significant differences(24.21%±6.55%vs 15.98%±3.03%,P<0.05;9.09%±1.91%vs 5.49%±1.00%,P<0.001;80.51%±2.96%vs 75.31%±4.34%,P<0.05).The expression of CD8+T lymphocytes and B lymphocytes in the ImmTOR treatment group also decreased(9.09%±1.91%vs 5.49%±1.00%,P<0.001;80.51%±2.96%vs 75.31%±4.34%,P<0.05).The liver pathology of PBC mice in the treatment group showed reduced inflammation and a decreased total pathology score,and the difference in the scores was statistically significant(4.50±2.88 vs 1.75±1.28,P<0.05).CONCLUSION ImmTOR can improve biochemistry and pathology of liver obvious by inhibiting the expression of CD8+T cells and B cells,and reducing the titer of AMA.
