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层合板分层失效数值模拟与参数识别

浙江大学学报（工学版） 2017年第5期51卷 954-960,968页

作者：籍庆辉朱平卢家海上海汽车集团股份有限公司前瞻技术研究部上海201804 上海交通大学机械系统与振动国家重点实验室上海200240 上海交通大学上海市复杂薄板结构数字化制造重点实验室上海200240

为了精确预测纤维增强复合材料层合板分层失效问题,提出基于虚拟裂纹闭合法的复合材料层合板分层失效准则参数的识别方法.通过双悬臂梁(DCB)试样和末端缺口弯曲(ENF)试样准静态力学试验获得I型和Ⅱ型分层断裂韧性.综合虚拟裂纹闭合法和... 详细信息

为了精确预测纤维增强复合材料层合板分层失效问题,提出基于虚拟裂纹闭合法的复合材料层合板分层失效准则参数的识别方法.通过双悬臂梁(DCB)试样和末端缺口弯曲(ENF)试样准静态力学试验获得I型和Ⅱ型分层断裂韧性.综合虚拟裂纹闭合法和有限元法,分别建立I型、Ⅱ型以及I/Ⅱ混合型分层数值仿真模型.基于已有的分层混合模式试验数据验证该方法的有效性.针对汽车用平纹机织碳纤维复合材料,利用纯I型和纯Ⅱ型试验和混合模式弯曲试样仿真模型,对分层失效准则参数进行了识别.结果表明,运用所建立的参数识别方法能够准确地得到层合板分层失效准则参数,有效克服了传统试验方法获取失效参数的成本高和周期长的问题.

关键词：虚拟裂纹闭合法分层失效准则有限元分析(FEA) 参数识别

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基于大数据的精准志愿服务研究

学术探索 2017年第3期 77-82页

作者：蒲清平王婕朱丽萍重庆大学思想政治教育研究中心重庆400044 河南理工大学能源科学与工程学院河南焦作454003

志愿服务是推进社会治理、实现"善治"的重要手段,然而目前中国志愿服务却陷入服务不当、共享不足、管理错位、评价失效的"志愿失灵"困境。采取大数据诊断服务对象主体诉求、云平台共建共享志愿服务数据、全方位优化志愿服务体制机制、... 详细信息

志愿服务是推进社会治理、实现"善治"的重要手段,然而目前中国志愿服务却陷入服务不当、共享不足、管理错位、评价失效的"志愿失灵"困境。采取大数据诊断服务对象主体诉求、云平台共建共享志愿服务数据、全方位优化志愿服务体制机制、多渠道收集志愿服务量化数据,实现精心服务、精确匹配、精细管理、精准评估的精准志愿服务,是破解中国"志愿失灵"的有效路径。

关键词：精准志愿服务大数据志愿失灵

Effect of pyrite content on chalcopyrite flotation under different regrinding conditions

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International Journal of Minerals,Metallurgy and Materials 2025年第1期32卷 49-57页

作者： Zejun Wang qing Shi Guofan Zhang Yuxuan zhu Binbin Li School of Minerals Processing and Bioengineering Central South UniversityChangsha 410083China Key Laboratory of Hunan Province for Clean and Efficient Utilization of Strategic Calcium-containing Mineral Resources Central South UniversityChangsha 410083China

This study aimed to investigate the effect of varying pyrite(Py)content on copper(Cu)in the presence of different regrinding conditions,which were altered using different types of grinding media:iron,ceramic balls,and their mixture,followed by flotation in the cleaner *** flotation performance of rough Cu concentrate can be improved by changing the regrinding conditions based on the Py *** electron microscopy,X-ray spectrometry,ethylenediaminetetraacetic acid disodium salt extraction,and X-ray photoelectron spectroscopy studies illustrated that when the Py content was high,the use of iron media in regrinding promoted the generation of hydrophilic Fe OOH on the surface of Py and improved the Cu *** ceramic medium with a low Py content prevented excessive Fe OOH from covering the surface of chalcopyrite(Cpy).Electrochemical studies further showed that the galvanic corrosion current of Cpy-Py increased with the addition of Py and became stronger with the participation of iron media.

关键词： chalcopyrite regrinding media pyrite galvanic corrosion flotation

红莲型细胞质雄性不育水稻线粒体atp6基因转录本的编辑位点研究

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生物化学与生物物理进展 2002年第5期29卷 729-733页

作者：易平汪莉孙清萍朱英国武汉大学生命科学学院植物发育生物学教育部重点实验室武汉430072

以红莲 (HL)型水稻细胞质雄性不育系A、保持系B及杂种一代F1为材料 ,首次比较研究了红莲型水稻线粒体atp6基因转录本的编辑位点及各位点的编辑频率 .结果表明atp6基因的转录本有 18个编辑位点 ,其中有 15个发生在密码子的第一和第二位点... 详细信息

以红莲 (HL)型水稻细胞质雄性不育系A、保持系B及杂种一代F1为材料 ,首次比较研究了红莲型水稻线粒体atp6基因转录本的编辑位点及各位点的编辑频率 .结果表明atp6基因的转录本有 18个编辑位点 ,其中有 15个发生在密码子的第一和第二位点上 ,这些位点的编辑最终会导致氨基酸种类的变化 .18个编辑位点在A、B和F1中没有差异 ,但各位点的编辑频率在引入了核恢复基因的条件下发生了较大的变化 ,完全编辑的比例增加 .这些结果首次证明HL型细胞质雄性不育与线粒体atp6转录本的编辑有一定相关性。

关键词：红莲型细胞质雄性不育水稻线粒体 atp6基因转录本编辑位点

PAI-2抑制细胞凋亡依赖其蛋白质结合功能域

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生物化学与生物物理学报 2000年第2期32卷 175-178页

作者：田昱沈俊卿李平朱运松上海医科大学基础医学院分子遗传学研究室!上海200032

将纤溶酶原激活剂抑制物 2型 (PAI 2 )突变体PAI 2CD和PAI 2QcDNA与真核表达载体 pcDNA3重组 ,构建真核表达质粒并转染HeLa细胞 ,经G4 18筛选 ,Northern印迹鉴定和ELISA检测 ,筛选出稳定表达PAI 2CD和PAI 2Q的阳性细胞株。ELISA结果表明... 详细信息

将纤溶酶原激活剂抑制物 2型 (PAI 2 )突变体PAI 2CD和PAI 2QcDNA与真核表达载体 pcDNA3重组 ,构建真核表达质粒并转染HeLa细胞 ,经G4 18筛选 ,Northern印迹鉴定和ELISA检测 ,筛选出稳定表达PAI 2CD和PAI 2Q的阳性细胞株。ELISA结果表明PAI 2突变蛋白质在转染细胞中的表达量与相应野生型PAI 2在阳性细胞克隆中的表达量基本相近 ,PAI 2及其突变体在理化、生物学性质上也基本一致 ,而结晶紫染色、MTT法证实PAI 2突变体均未能抑制肿瘤坏死因子 α(TNF α)的细胞毒性作用。结果表明PAI 2抑制TNF α诱导的细胞凋亡作用依赖PAI 2螺旋CD间的环状结构所介导的蛋白质与蛋白质间的作用 ;而谷氨酰胺转移酶 (tTG)所介导的PAI 2与其他胞内蛋白质的相互作用可能是凋亡抑制中的关键作用。

关键词：纤溶酶原激活剂抑制物2型细胞凋亡肿瘤坏死因子-α

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PAI-2及其突变体的生物化学性质

生物化学与生物物理学报 2000年第2期32卷 126-132页

作者：田昱沈俊卿李平朱运松上海医科大学基础医学院分子遗传学研究室!上海200032

为研究和比较纤溶酶原激活剂抑制物 2型 (plasminogenactivatorinhibitortype 2 ,PAI 2 )及其突变体的生物化学性质 ,用PCR、体外定点突变技术构建PAI 2突变体PAI 2CD和PAI 2QcDNA ,将突变体cDNA与原核表达载体重组并转化大肠杆菌。经... 详细信息

为研究和比较纤溶酶原激活剂抑制物 2型 (plasminogenactivatorinhibitortype 2 ,PAI 2 )及其突变体的生物化学性质 ,用PCR、体外定点突变技术构建PAI 2突变体PAI 2CD和PAI 2QcDNA ,将突变体cDNA与原核表达载体重组并转化大肠杆菌。经诱导表达 ,SDS PAGE证实表达出相应蛋白质 ,均占全菌总蛋白质的 14 %。Wes tern印迹、溶圈抑制及纤维蛋白翻转板法证实表达产物具有PAI 2免疫原性和纤溶抑制活性。细菌大量表达后 ,5L发酵液可得湿菌约 10 0 g ,经破菌、硫酸铵分级沉淀、分子筛、离子交换和疏水性层析等步骤分离 ,每升发酵液菌体得纯度达 98%的PAI 2CD约 3 6mg ,比活性为 2 864 0u/mg ;纯度达 90 %的PAI 2Q约 3 8mg ,比活性为 14 83 6u/mg。经复性后 ,除PAI 2Q无法受组织型谷氨酰胺转移酶 (tissuetypetransglutaminase ,tTG)的催化外 ,突变体蛋白质的其他理化性质和生物学特性 (抑制尿激酶的二级速率常数、热稳定性、pH稳定性、对盐酸胍及氧化剂的耐受性 )均与野生型PAI 2的基本一致。

关键词：纤溶酶原激活剂抑制物2型突变表达和纯化

Characteristic changes in astrocyte properties during astrocyte-to-neuron conversion induced by NeuroD1/Ascl1/Dlx2

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Neural Regeneration Research 2025年第6期20卷 1801-1815页

作者： qing He Zhen Wang Yuchen Wang Mengjie zhu Zhile Liang Kanghong Zhang Yuge Xu Gong Chen GHM Institute of CNS Regeneration Jinan UniversityGuangzhouGuangdong ProvinceChina

Direct in vivo conversion of astrocytes into functional new neurons induced by neural transcription factors has been recognized as a potential new therapeutic intervention for neural injury and degenerative disorders. However, a few recent studies have claimed that neural transcription factors cannot convert astrocytes into neurons, attributing the converted neurons to pre-existing neurons mis-expressing transgenes. In this study, we overexpressed three distinct neural transcription factors––NeuroD1, Ascl1, and Dlx2––in reactive astrocytes in mouse cortices subjected to stab injury, resulting in a series of significant changes in astrocyte properties. Initially, the three neural transcription factors were exclusively expressed in the nuclei of astrocytes. Over time, however, these astrocytes gradually adopted neuronal morphology, and the neural transcription factors was gradually observed in the nuclei of neuron-like cells instead of astrocytes. Furthermore,we noted that transcription factor-infected astrocytes showed a progressive decrease in the expression of astrocytic markers AQP4(astrocyte endfeet signal), CX43(gap junction signal), and S100β. Importantly, none of these changes could be attributed to transgene leakage into preexisting neurons. Therefore, our findings suggest that neural transcription factors such as NeuroD1, Ascl1, and Dlx2 can effectively convert reactive astrocytes into neurons in the adult mammalian brain.

关键词： aquaporin-4 Ascl1 astrocyte cortex Dlx2 gap junction glia-to-neuron conversion neural regeneration NeuroD1 reprogramming

Trinuclear gold-catalyzed site-selective alkylation of peptides

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Science China Chemistry 2025年第01期 249-256页

作者： qing-Yun Fang Chengyihan Gu Yinghan Chen Wencheng Yan Yong Liang Weipeng Li Chengjian zhu Jie Han Jin Xie State Key Laboratory of Coordination Chemistry Jiangsu Key Laboratory of Advanced Organic Materials Chemistry and Biomedicine Innovation Center (Chem BIC) School of Chemistry and Chemical Engineering Nanjing University Green Catalysis Center College of Chemistry Zhengzhou University State Key Laboratory of Natural Medicines China Pharmaceutical University

Selective modification of peptides has always been a challenging issue. The selective alkylation of peptides can alter the biological activity and physical properties of molecules, and it has gained significant research interest. We herein disclose an intriguing gold-catalyzed alkylation of peptides using bench-stable unactivated alkyl bromides under photoredox catalysis. A wide range of structurally diverse primary, secondary and tertiary alkyl bromides serve as effective coupling partners to precisely connect with the α-C(sp3)–H in glycine residue of peptides. This protocol demonstrates an exceptionally broad scope for alkyl halides and excellent tolerance for a wide range of useful functional groups. A series of relay transformations to construct cyclic peptides, to proceed click reaction and to realize peptide fluorescence labeling further enhance its synthetic practicality. In addition, mechanistic studies and density functional theory(DFT) calculations reveal an inner-sphere and subsequent outersphere single electron transfer(SET) mechanism.

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Effects of Bifidobacterium lactis BLa80 on fecal and mucosal flora and stem cell factor/c-kit signaling pathway in simulated microgravity rats

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World Journal of Gastroenterology 2025年第1期31卷 93-109页

作者： ping Zhang Ying zhu Pu Chen Tong Zhou Zhe-Yi Han Jun Xiao Jian-Feng Ma Wen Ma Peng Zang Ying Chen Graduate School Hebei North UniversityZhangjiakou 075000Hebei ProvinceChina Key Laboratory of Aerospace Nutrition and Food Engineering China Astronaut Research and Training CenterBeijing 100094China Department of Gastroenterology The Air Force Medical CenterBeijing 100142China Department of Blood Transfusion Air Force Medical CenterBeijing 100142China

BACKGROUND Simulated microgravity environment can lead to gastrointestinal motility *** pathogenesis of gastrointestinal motility disorders is closely related to the stem cell factor(SCF)/c-kit signaling pathway associated with intestinal flora and Cajal stromal ***,intestinal flora can also affect the regulation of SCF/c-kit signaling pathway,thus affecting the expression of Cajal stromal *** cells are the pacemakers of gastrointestinal *** To investigate the effects of Bifidobacterium lactis(***)BLa80 on the intestinal flora of rats in simulated microgravity and on the gastrointestinal motility-related SCF/c-kit *** The internationally recognized tail suspension animal model was used to simulate the microgravity environment,and 30 rats were randomly divided into control group,tail suspension group and drug administration tail suspension group with 10 rats in each group for a total of 28 *** tail group was given *** BLa80 by intragastric administration,and the other two groups were given water intragastric administration,the concentration of intragastric administration was 0.1 g/mL,and each rat was 1 mL/***&eosin staining was used to observe the histopathological changes in each segment of the intestine of each group,and the expression levels of SCF,c-kit,extracellular signal-regulated kinase(ERK)and p-ERK in the gastric antrum of each group were detected by Western blotting and *** fecal flora and mucosal flora of rats in each group were detected by 16S *** Simulated microgravity resulted in severe exfoliation of villi of duodenum,jejunum and ileum in rats,marked damage,increased space between villi,loose arrangement,shortened columnar epithelium of colon,less folds,narrower mucosal thickness,reduced goblet cell number and crypts,and significant improvement after probiotic *** microgravity reduced the expressions of SCF and c-kit,and increased the express

关键词： Simulated microgravity Rat Intestinal flora Gastrointestinal motility Stem cell factor/c-kit signaling pathway