基于DELMIA的虚拟装配中人机工程仿真与应用

在虚拟装配中．可以通过人机工程的仿真和运用来评估虚拟装配设计的质量和零部件的装配可达性。本文将人体模型作为虚拟装配的一个重要因素来研究．根据DELMIA中人体模型特点,阐述了人机工程在虚拟装配中的应用,并在DELMIA中进行了人机工程仿真应用示例。     

Interleukin-1β inhibits AKT to down-regulate eNOS Ser1177 phosphorylation in human umbilical vein endothelial cells

AIM To investigate whether interleukin-1β （IL-1β） regulates endothelial nitric oxide synthase （eNOS） phosphorylation at Ser1177 site in human umbilical vein endothelial cells （HUVECs）, and to explore its possible mechanism. METHODS The HUVECs were randomly divided into normal control group, tumor necrosis factor-α （TNF-α） group, IL-1β group, IL-6 group, SC79 ［protein kinase B （PKB/AKT） specific agonist］ group and SC79+IL-1β group. Western blot was used to determine the protein levels of eNOS, p-eNOS-Ser1177, AKT and p-AKT-Ser473 in the HUVECs. Chemical colorimetry was used to detect the nitric oxide （NO） content in the culture medium of HUVECs. RESULTS No statistically significant difference of p-eNOS-Ser1177 level in HUVECs treated with TNF-α and IL-6 was observed as compared with normal control group （P>0.05）, while the protein level of p-eNOS-Ser1177 in the HUVECs and the content of NO in the culture medium of HUVECs decreased significantly in IL-1β group （P<0.05）, and the protein level of p-AKT-Ser473 in the HUVECs was decreased as compared with normal control group （P<0.05）. The AKT agonist SC79 blocked the down-regulation effect of IL-1β on p-eNOS-Ser1177 level in the HUVECs and NO content in the culture medium of HUVECs （P<0.05）. CONCLUSION IL-1β down-regulates the protein level of p-eNOS-Ser1177 in HUVECs and affects the activity of eNOS, which may be involved in AKT/eNOS signaling pathway.     

MicroRNA-142-3p modulates atherosclerosis-associated endothelial cell apoptosis via targeting Rictor

AIM To investigate the role of microRNA-142-3p （miR-142-3p） in endothelial cell apoptosis during atherosclerosis （AS） and the underlying mechanism. METHODS Human aortic endothelial cells （HAECs） were treated with oxidized low-density lipoprotein （ox-LDL）. The expression level of miR-142-3p was detected by RT-qPCR. Apoptosis was determined via flow cytometry （FCM） and caspase-3 activity assay. Prediction of the binding site between miR-142-3p and 3’-UTR of Rictor mRNA was performed by bioinformatics analysis and confirmed by dual-luciferase reporter assay. RESULTS The expression of miR-142-3p was substantially up-regulated during the ox-LDL-elicited apoptosis in HAECs （P<0.05,P<0.01）. Forced expression of miR-142-3p exacerbated apoptosis in HAECs whereas inhibition of miR-142-3p partly alleviated apoptotic cell death mediated by ox-LDL. Further analysis identified Rictor as a direct target gene of miR-142-3p, and Rictor knock-down abolished the anti-apoptotic effect of miR-142-3p inhibitor. Moreover, the Akt/endothelial nitric oxide synthase （eNOS） signaling pathway was found to mediate the beneficial effect of miR-142-3p inhibitor on endothelial cells apoptosis. CONCLUSION Down-regulation of miR-142-3p inhibits endothelial cell apoptosis and atherosclerotic development by up-regulating the expression of Rictor and activating the Akt/eNOS signaling pathway.     

Effect of xeroderma pigmentosum group D gene on proliferation of human umbilical arterial smooth muscle cells induced by Ox-LDL

AIM: To investigate the effects of xeroderma pigmentosum group D (XPD) gene on the proliferation of human umbilical arterial smooth muscle cells (HUASMCs) induced by oxidized low-density lipoprotein (Ox-LDL). METHODS: The recombinant plasmid pEGFP-N2/XPD was transfected into HUASMCs by liposome. The cells were divided into blank control group, pEGFP-N2 group, pEGFP-N2/XPD group, Ox-LDL group, Ox-LDL+pEGFP-N2 group and Ox-LDL+pEGFP-N2/XPD group. The proliferation rate of the cells was detected by MTT and EdU assays. The apoptotic rate and cell cycle distribution were analyzed by flow cytometry. The protein levels of XPD, caspase-3, Bcl-2 and Bax were determined by Western blot. RESULTS: Compared with blank control group, the expression of XPD was increased in pEGFP-N2/XPD group (P<0.05). According to the results of MTT and EdU assays, the cell proliferation in pEGFP-N2/XPD group was reduced compared with blank control group (P<0.05). Compared with Ox-LDL group, the cell proliferation in Ox-LDL+pEGFP-N2/XPD group was significantly inhibited (P<0.05). According to the results of flow cytometry, the cell proportion of S phase decreased and the G₀/G₁-phase cell proportion increased significantly in pEGFP-N2/XPD group and Ox-LDL+pEGFP-N2/XPD group compared with blank control group and Ox-LDL group, repectively (P<0.05). Compared with blank control group and Ox-LDL group, the protein level of Bcl-2 decreased and the protein levels of Bax and cleaved caspase-3 increased in pEGFP-N2/XPD group and Ox-LDL+pEGFP-N2/XPD group, respectively (P<0.05). CONCLUSION: XPD inhibits the proliferation of HUASMCs and promotes their apoptosis, and reduces the promoting effect of Ox-LDL on the proliferation of HUVSMCs. XPD may be the target for treatment of atherosclerosis.     

草菇子实体提取物的抗氧化活性

为考察草菇(Volvariella volvacea)子实体提取物(VBS)的抗氧化活性,测定了对两种自由基的清除率及其总还原力,结果表明:对羟自由基和DPPH自由基的清除率以及总还原力均与VBS的浓度存在正相关的量效关系,IC50值分别为1.40、0.67、0.63mg/mL。以ICR雄性小鼠为研究对象,灌胃给药12d,再用CCl4花生油溶液灌胃,8h后分别测定超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、丙氨酸氨基转移酶(ALT)和谷草转氨酶(AST)的活力及丙二醛(MDA)的含量,各项指标在血清中的结果表明,VBS中剂量组(200 mg/kg)的抗氧化活性较好,而在肝脏中则表明VBS高剂量组(400mg/kg)的抗氧化活性较好。     

泥炭覆土搅拌时间对覆土结构及双孢蘑菇产量和质量的影响

为优化双孢蘑菇(Agaricus bisporus)覆土技术,以泥炭为覆土材料,研究泥炭覆土搅拌时间对覆土物理结构以及对双孢蘑菇产量和质量的影响。结果证实,随搅拌时间的延长,泥炭覆土充气孔隙度降低,容重增加。充气孔隙度与双孢蘑菇产量高度正相关,但是与双孢蘑菇子实体大小及商品菇率高度负相关;覆土容重与双孢蘑菇产量高度负相关,但是与双孢蘑菇子实体大小及商品菇率高度正相关。搅拌时间较短的覆土(5~20 min),双孢蘑菇总产量较高,且每潮菇产量更均匀,更有利于工厂化生产。搅拌时间较长的覆土(40~120 min),双孢蘑菇子实体较大,但是会降低双孢蘑菇的总产量以及影响每潮菇产量的均匀性。本试验条件下泥炭覆土最适搅拌时间为10 min,双孢蘑菇3潮菇总产量34.5 kg/m~2,商品菇产量27 kg/m~2。研究初步揭示覆土物理结构对双孢蘑菇产量及质量的影响,为优化覆土技术及筛选优质覆土材料提供参考。     

PLA膜包装对白玉菇子实体保鲜效果的研究

为了研究PLA膜包装对白玉菇子实体的保鲜效果,以未包装和PE膜包装为对照,考察了在20~25℃,相对湿度90%条件下贮藏5天,PLA膜包装对白玉菇子实体感官评分和各项生理指标的影响。结果表明：贮藏5天时间内,相对于未包装和PE膜包装,PLA膜包装能使白玉菇子实体感官品质好、硬度高、水分失重低、褐变小、CAT酶下降小、PPO酶上升少、微生物总菌量滋生少。PLA膜包装有利于抑制包装后白玉菇子实体的呼吸,减少总糖、氨基酸含量的降低,维持了白玉菇的感官质量与品质,使其具有更好的保鲜效果,货架期延长,产品商业价值更高。     

汽车车身导水主板导水槽结构设计

讲述了两种不同的车身前部导水槽结构,封闭式导水槽和单板式导水槽结构,并分别对两种导水槽的导水性、安装要求、焊接工艺性以及和周边零件搭接关系等技术问题进行了说明。并以某款汽车的前舱导水槽结构为例,展开讲述了汽车前舱导水主板总成中导水槽的结构特点和种类,以及在设计过程中需要注意的关键点。且列举了几种常用的导水槽结构,为导水槽设计时提供参考。     

基于ANSYS和ADAMS的玉米茎秆柔性体仿真

玉米柔性体模型的建立是研究玉米植株与玉米收获机构刚柔耦合多体动力学系统的关键步骤.根据玉米植株参数,通过有限元软件ANSYS建立了茎秆模型,对模型进行网格划分和接触点定义,生成ADAMS需要的模态中性文件.将建立的收获机构模型和模态中性文件导入ADAMS后,施加载荷、约束和驱动,对茎秆的运动状态进行了模拟,得出茎秆位置、速度等试验数据,研究茎秆在机构间的运动状态,为后续分析提供依据.     

不同空间粒度下地表水体分布格局多样性研究

选取河南省北部、中部和南部典型研究样区,将空间粒度方法引入并应用于地表水体多样性的研究中。在总结前人研究水体多样性测度方法的基础上,提出新的方法——空间分布长度指数(MSHDLI),并在1 km×1 km网格尺度下研究MSHDLI、水网密度(RD)和空间分布面积指数(MSHDAI)的粒度效应、相关性和相关系数的粒度响应、尺度效应关系及回归模型。结果表明:随着粒度的增加,MSHDLI、RD和MSHDAI的粒度响应曲线均为下降型;MSHDLI与RD和MSHDAI有显著的相关关系,平均相关系数r分别为0.997和0.878(P0.01),且MSHDLI与RD、MSHDAI相关系数的粒度效应属于显著正相关关系;MSHDLI与RD的拟合度函数均是对数函数,MSHDLI与MSHDAI的拟合度函数均是多项式函数;由三者的多元线性回归模型可知MSHDLI与RD、MSHDAI线性相关且对它们的解释程度达到95%以上。MSHDLI可以将RD描述水资源广度和MSHDAI描述水资源空间分布离散性的优势结合起来。