Estimation of density and hazard rate is very important to the reliability analysis of a system. In order to estimate the density and hazard rate of a hazard rate monotonously decreasing system, a new nonparametric es...Estimation of density and hazard rate is very important to the reliability analysis of a system. In order to estimate the density and hazard rate of a hazard rate monotonously decreasing system, a new nonparametric estimator is put forward. The estimator is based on the kernel function method and optimum algorithm. Numerical experiment shows that the method is accurate enough and can be used in many cases.展开更多
This experiment used pumpkin Longyuanlixiang as material to research the effect of different pruning ways with one branch, two branches, and three branches on the sugar-decreasing matters during the ripeness of pumpk...This experiment used pumpkin Longyuanlixiang as material to research the effect of different pruning ways with one branch, two branches, and three branches on the sugar-decreasing matters during the ripeness of pumpkin （Cucurbita moschata） fruits. The results showed that pectin contents of pumpkin fruits during the ripeness all increased at first and then dropped in every treatment. The pectin contents under the treatments of one branch and two branches reached the high apex after pollinated for 30 d as well as for 35 d under the treatment of three branches. Pentose and chromium contents of fruits had the same trend under different pruning ways and increased during the ripenes. Three kinds of sugar-decreasing matters contents under treatment of two branches were bigger than treatment of one branch, while treatment of three branches was the lowest.展开更多
为了解产热对动物免疫能力的影响,通过肩胛间褐色脂肪组织(interscapular brown adipose tissue,IBAT)切除术和低温处理,将雌性黑线仓鼠(Cricetulus barabensis)随机分为常温假切组(warm BAT sham‑removed group,WS,n=5)、低温假切组(co...为了解产热对动物免疫能力的影响,通过肩胛间褐色脂肪组织(interscapular brown adipose tissue,IBAT)切除术和低温处理,将雌性黑线仓鼠(Cricetulus barabensis)随机分为常温假切组(warm BAT sham‑removed group,WS,n=5)、低温假切组(cold BAT sham‑removed group,CS,n=7)和低温切除组(cold BAT removed group,CR,n=8),比较了产热和免疫器官大小及血液指标和免疫功能的差异。结果发现,切除IBAT或逐渐降温均不影响雌性黑线仓鼠的体质量和身体成分,但低温导致总脂肪质量下降。切除IBAT不影响肝脏、脾脏和胸腺等器官的鲜质量,提示器官水平产热和免疫之间无权衡关系,但逐渐降温增加了小肠鲜质量及长度、结肠鲜质量、总消化道长,暗示为满足低温下的高能量需求,其加工食物的能力和消化能力均有所增强。切除IBAT或逐渐降温不影响植物血球凝集素反应峰值,以及白细胞、淋巴细胞、中间粒细胞和中性粒细胞的数量。低温或切除IBAT不影响雌性黑线仓鼠的免疫功能。展开更多
This work identified the important role of matrix mechanical plasticity in mediating fibroblast activation.Many existing studies have highlighted the important effects of biochemical cues(e.g.,transforming growth fact...This work identified the important role of matrix mechanical plasticity in mediating fibroblast activation.Many existing studies have highlighted the important effects of biochemical cues(e.g.,transforming growth factor-β1)and mechanicalstiffness on fibroblast activation.Our results indicated that self-assembled collagen hydrogels showed high plasticity and in which fibroblasts remain undifferentiated.However,when we decreased the plasticity of collagen hydrogels by increasing covalent crosslinking,fibroblasts showed a significant fibrotic response as reflected by the increasedα-SMA expression.Since the material systems we constructed have low and the same initial modulus,this process is stiffness independent.Although it has been reported that covalently crosslinked hydrogels are more difficult to degrade and matrix degradability has an important impact on cell behaviors,no significant changes of fibroblast activation were observed when proteases were broadly inhibited in our experiments.Importantly,the hydrogels we constructed showed similar plastic behaviors under creep and recovery tests compared to native normal and fibrotic tissues.These highlight the importance of matrix plasticity in mimicking the mechanical microenvironment of native fibrotic tissues.Mechanistically,we found that the enhanced fibroblast activation in low plastic matrix is mediated through integrin-actin pathway and nuclear localization of YAP.In high plastic collagen,matrix cannot provide effective resistance to actin contraction because of the rupture of weak crosslinks and the slippage of local fibers.On the contrary,in low plastic collagen,deformation energy can be stored in the network due to the existence of strong covalent crosslinks,thus enabling the build-up of cell traction and the formation of a robust cell-matrix interaction.Experiments of inhibiting or promoting cytoskeletal contractility and CGMD simulation both verified the above points.Our results clarify plasticity changes on the development of fibrotic diseases and highlight plasticity as an important mechanical cue in understanding cell-matrix interactions.展开更多
文摘Estimation of density and hazard rate is very important to the reliability analysis of a system. In order to estimate the density and hazard rate of a hazard rate monotonously decreasing system, a new nonparametric estimator is put forward. The estimator is based on the kernel function method and optimum algorithm. Numerical experiment shows that the method is accurate enough and can be used in many cases.
基金Supported by Heilongjiang Province Natural Science Foundation (C2004-24)
文摘This experiment used pumpkin Longyuanlixiang as material to research the effect of different pruning ways with one branch, two branches, and three branches on the sugar-decreasing matters during the ripeness of pumpkin （Cucurbita moschata） fruits. The results showed that pectin contents of pumpkin fruits during the ripeness all increased at first and then dropped in every treatment. The pectin contents under the treatments of one branch and two branches reached the high apex after pollinated for 30 d as well as for 35 d under the treatment of three branches. Pentose and chromium contents of fruits had the same trend under different pruning ways and increased during the ripenes. Three kinds of sugar-decreasing matters contents under treatment of two branches were bigger than treatment of one branch, while treatment of three branches was the lowest.
文摘为了解产热对动物免疫能力的影响,通过肩胛间褐色脂肪组织(interscapular brown adipose tissue,IBAT)切除术和低温处理,将雌性黑线仓鼠(Cricetulus barabensis)随机分为常温假切组(warm BAT sham‑removed group,WS,n=5)、低温假切组(cold BAT sham‑removed group,CS,n=7)和低温切除组(cold BAT removed group,CR,n=8),比较了产热和免疫器官大小及血液指标和免疫功能的差异。结果发现,切除IBAT或逐渐降温均不影响雌性黑线仓鼠的体质量和身体成分,但低温导致总脂肪质量下降。切除IBAT不影响肝脏、脾脏和胸腺等器官的鲜质量,提示器官水平产热和免疫之间无权衡关系,但逐渐降温增加了小肠鲜质量及长度、结肠鲜质量、总消化道长,暗示为满足低温下的高能量需求,其加工食物的能力和消化能力均有所增强。切除IBAT或逐渐降温不影响植物血球凝集素反应峰值,以及白细胞、淋巴细胞、中间粒细胞和中性粒细胞的数量。低温或切除IBAT不影响雌性黑线仓鼠的免疫功能。
基金financially supported by the National Natural Science Foundation of China ( 11872298, 11602191,11532009,11621062)the China Postdoctoral Science Foundation ( 2018M631141)the Fundamental Research Funds for the Central Universities ( Z201811336)
文摘This work identified the important role of matrix mechanical plasticity in mediating fibroblast activation.Many existing studies have highlighted the important effects of biochemical cues(e.g.,transforming growth factor-β1)and mechanicalstiffness on fibroblast activation.Our results indicated that self-assembled collagen hydrogels showed high plasticity and in which fibroblasts remain undifferentiated.However,when we decreased the plasticity of collagen hydrogels by increasing covalent crosslinking,fibroblasts showed a significant fibrotic response as reflected by the increasedα-SMA expression.Since the material systems we constructed have low and the same initial modulus,this process is stiffness independent.Although it has been reported that covalently crosslinked hydrogels are more difficult to degrade and matrix degradability has an important impact on cell behaviors,no significant changes of fibroblast activation were observed when proteases were broadly inhibited in our experiments.Importantly,the hydrogels we constructed showed similar plastic behaviors under creep and recovery tests compared to native normal and fibrotic tissues.These highlight the importance of matrix plasticity in mimicking the mechanical microenvironment of native fibrotic tissues.Mechanistically,we found that the enhanced fibroblast activation in low plastic matrix is mediated through integrin-actin pathway and nuclear localization of YAP.In high plastic collagen,matrix cannot provide effective resistance to actin contraction because of the rupture of weak crosslinks and the slippage of local fibers.On the contrary,in low plastic collagen,deformation energy can be stored in the network due to the existence of strong covalent crosslinks,thus enabling the build-up of cell traction and the formation of a robust cell-matrix interaction.Experiments of inhibiting or promoting cytoskeletal contractility and CGMD simulation both verified the above points.Our results clarify plasticity changes on the development of fibrotic diseases and highlight plasticity as an important mechanical cue in understanding cell-matrix interactions.
