检索结果-南通市图书馆

Mechanistic Study on the Dominant Promotion Effect of Al-/Ti-/Zr-modifications over the VOx/SiO2 UHMWPE Catalysts

Chinese Journal of Polymer Science 2019年第10期37卷 995-1004,I0004页

作者： Yu-Long Jin Lin liu Yu-Jie Wang Zhen liu bo-ping liu College of Materials and Energy South China Agricultural UniversityGuangzhou 510642China School of Chemical Engineering East China University of Science and TechnologyShanghai 200237China

Recently, we reported the first VOx/SiO2 ethylene polymerization catalyst for making Cl-free UHMWPE, and found the dominant promotion effects of Al-/Ti-/Zr-modifications over this catalyst system(Macromol. Chem. Phys. 2017, 218, 1600443). In this work, density functional theory is applied to investigate the underlying mechanism of this remarkable promotion effect of Al-/Ti-/Zrmodifications on a molecular and atomic level. The cluster model with V(Ⅲ) is found to be the most possible active site due to its lowest overall energy barrier for monomer insertion, though the process of C2H4 coordination and the subsequent formation of transition state are most energy favored for V(Ⅱ) species. By modifying one of or both V―O―Si in the active model with V―O―M(M = Al, Ti, or Zr),the energy barrier for the binding of the upcoming C2H4 gets lower(particularly for Al-and Zr-modified catalysts), and the transition state also becomes more stable. Generally, the insertion process of C2H4 gets easier after support Al-/Ti-/Zr-modifications. This dominant promotion effect is partially ascribed to the more enriched positive charge distribution on or nearby the V center, and the narrower energy gap between the LUMO of model catalysts and the HOMO of C2H4 for these modified catalysts also contributes much. In addition, the decreased steric hindrance around the V center should be taken into account for the modified models as well. Furthermore, the Br?nsted acidity of the catalysts is investigated by introducing a pendent hydroxyl group to the model catalysts, which has a close contact with the V center. Similar promotion effect of support modification by Al, Ti, and Zr could still be observed.

关键词： Density functional theory Vanadium-oxides Ethylene polymerization Support modification Mechanism

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

复方板蓝根颗粒APCI-MS指纹图谱及化学成分的LC-APCI-MS^n研究

引用

质谱学报 2017年第3期38卷 320-327页

作者：闫峻刘舒李伯平刘志强郭冬发核工业北京地质研究院北京100029 中国科学院长春应用化学研究所吉林长春130022

建立了复方板蓝根颗粒提取物的大气压化学电离质谱(APCI-MS)的指纹图谱分析方法,并利用液相色谱-大气压化学电离-串联质谱(LC-APCI-MS^n)技术对主要指纹峰的归属进行确认。结果表明:质谱指纹图谱确定了10批不同来源复方板蓝根颗粒提取物... 详细信息

建立了复方板蓝根颗粒提取物的大气压化学电离质谱(APCI-MS)的指纹图谱分析方法,并利用液相色谱-大气压化学电离-串联质谱(LC-APCI-MS^n)技术对主要指纹峰的归属进行确认。结果表明:质谱指纹图谱确定了10批不同来源复方板蓝根颗粒提取物的10个共有峰,各提取物的指纹图谱相似度均在97%以上。化学成分的LC-APCI-MS^n分析鉴别了复方板蓝根颗粒提取物中吲哚类、奎唑酮类、有机酸类和卟啉类等12个化合物,并确定了5个质谱指纹峰的归属。采用体外实验研究对复方板蓝根颗粒提取物的抗病毒活性进行评价,结果表明,其具有一定的抗病毒活性。该指纹图谱的精密度、稳定性和重现性良好,化学成分分析快捷、灵敏,结合化学成分分析和药效学研究,可为复方板蓝根颗粒质量控制标准的制订奠定基础,同时也为深入研究其药效物质基础和谱效关系提供理论依据。

关键词：复方板蓝根颗粒指纹图谱液相色谱-大气压化学电离-串联质谱法(LC-APCI-MSn) 抗病毒活性

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Human-induced pluripotent stem cell-derived neural stem cell exosomes improve blood-brain barrier function after intracerebral hemorrhage by activating astrocytes via PI3K/AKT/MCP-1 axis

引用

Neural Regeneration Research 2025年第2期20卷 518-532页

作者： Conglin Wang Fangyuan Cheng Zhaoli Han bo Yan Pan Liao Zhenyu Yin Xintong Ge Dai Li Rongrong Zhong Qiang liu Fanglian Chen ping Lei Department of Geriatrics Tianjin Medical University General HospitalTianjinChina School of Medicine Nankai UniversityTianjinChina Tianjin Neurological Institute TianjinChina

Cerebral edema caused by blood-brain barrier injury after intracerebral hemorrhage is an important factor leading to poor ***-induced pluripotent stem cell-derived neural stem cell exosomes(hiPSC-NSC-Exos)have shown potential for brain injury repair in central nervous system *** this study,we explored the impact of hiPSC-NSC-Exos on blood-brain barrier preservation and the underlying *** results indicated that intranasal delivery of hiPSC-NSC-Exos mitigated neurological deficits,enhanced blood-brain barrier integrity,and reduced leukocyte infiltration in a mouse model of intracerebral ***,hiPSC-NSC-Exos decreased immune cell infiltration,activated astrocytes,and decreased the secretion of inflammatory cytokines like monocyte chemoattractant protein-1,macrophage inflammatory protein-1α,and tumor necrosis factor-αpost-intracerebral hemorrhage,thereby improving the inflammatory *** sequencing indicated that hiPSC-NSC-Exo activated the PI3K/AKT signaling pathway in astrocytes and decreased monocyte chemoattractant protein-1 secretion,thereby improving blood-brain barrier *** with the PI3K/AKT inhibitor LY294002 or the monocyte chemoattractant protein-1 neutralizing agent C1142 abolished these *** summary,our findings suggest that hiPSC-NSC-Exos maintains blood-brain barrier integrity,in part by downregulating monocyte chemoattractant protein-1 secretion through activation of the PI3K/AKT signaling pathway in astrocytes.

关键词： AKT astrocyte blood-brain barrier cerebral edema exosomes human-induced pluripotent stem cells intracerebral hemorrhage neural stem cells neuroinflammation PI3K

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

氨基甲酰基季铵盐双功能催化剂催化丙交酯开环聚合研究

引用

高分子学报 2019年第12期50卷 1290-1297页

作者：李海强汪婧怡武莉刘威程瑞华刘柏平华东理工大学化学工程联合国家重点实验室上海200237 华南农业大学材料与能源学院广州510642

采用3种氨基甲酰基季铵盐双功能有机小分子催化剂考察了丙交酯的溶液聚合与本体聚合.催化剂由二甲酰亚胺和季铵盐在回流条件下以定量收率制备,原料廉价易得,在空气中性质稳定且毒性低,可在温和无惰性气体保护条件下催化丙交酯的开环聚合... 详细信息

采用3种氨基甲酰基季铵盐双功能有机小分子催化剂考察了丙交酯的溶液聚合与本体聚合.催化剂由二甲酰亚胺和季铵盐在回流条件下以定量收率制备,原料廉价易得,在空气中性质稳定且毒性低,可在温和无惰性气体保护条件下催化丙交酯的开环聚合.在以甲苯为溶剂的聚合条件下,a催化剂(2-氨基甲酰基苯甲酸四乙基铵)常温常压下反应1 h,丙交酯转化率为42.7%.由正交法得出的最佳聚合条件下,丙交酯/a催化剂/叔丁醇钠的摩尔比为200/10/1,75℃,反应4 h后,丙交酯转化率为88.5%,产物聚乳酸的分子量为8.03 kg·mol^-1.采用本体聚合的方法,3种催化剂均可在无引发剂的条件下合成聚乳酸.通过调控引发剂、金属醇盐及温度条件合成的聚乳酸,在150℃下丙交酯转化率达95.7%.几种方式所得产物熔融温度在130~134℃之间.产物经MALDI-TOF-MS表征,证实氨基甲酰基季铵盐催化剂具有协同双重活化单体和引发剂/链端的性能,双功能团位于同一结构中.

关键词：丙交酯双功能有机小分子催化剂开环聚合聚乳酸

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

紫外光照亲水性聚碳酸酯的合成及性能

引用

高分子学报 2019年第11期50卷 1202-1207页

作者：于伶伶程瑞华童钰涛刘柏平华东理工大学化学工程联合国家重点实验室上海200237 华南农业大学材料与能源学院广州510642

采用2-{[(2-硝基苯基)甲氧基]甲基}环氧乙烷(单体a)与二氧化碳(CO2)、环氧丙烷(PO)在SalenCo(Ⅲ)Cl/双(三苯基正膦基)氯化铵(PPNCl)催化下三元共聚,紫外(UV)光照脱除保护基,成功合成羟基官能化聚碳酸酯(PPC-OH).采用红外光谱、核磁共振... 详细信息

采用2-{[(2-硝基苯基)甲氧基]甲基}环氧乙烷(单体a)与二氧化碳(CO2)、环氧丙烷(PO)在SalenCo(Ⅲ)Cl/双(三苯基正膦基)氯化铵(PPNCl)催化下三元共聚,紫外(UV)光照脱除保护基,成功合成羟基官能化聚碳酸酯(PPC-OH).采用红外光谱、核磁共振、凝胶渗透色谱、接触角测量仪等对产物表征,结果表明:单体a成功引入聚碳酸酯骨架;SalenCo(Ⅲ)Cl催化剂表现出高催化活性、高选择性以及对第三单体良好的耐受性,聚合物碳酸酯单元含量>98%,首尾相连结构>99%,分子量分布极窄,CO2和环氧化物完美交替共聚.通过UV光照成功脱除羟基保护基生成PPC-OH,主链骨架无降解;单体a加入量至6%时,PPC-OH羟基含量增加至19.4%,水接触角由78.3°减小至57.6°,亲水性得到明显改善.

关键词：羟基官能化聚碳酸酯二氧化碳亲水性三元共聚 SalenCo(Ⅲ)Cl催化剂

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

转化生长因子-β1和丹参酮ⅡA联合诱导骨髓间充质干细胞向心肌样细胞的分化

引用

解剖学报 2016年第5期47卷 620-627页

作者：吕洋刘博王海萍刘源孙微李柔陈晓依河北北方学院组织学与胚胎学教研室河北北方学院附属第一医院病理科河北张家口075000

目的探讨转化生长因子-β1(TGF-β1)与丹参酮ⅡA(tanshinoneⅡA)联合诱导对大鼠骨髓间充质干细胞(BMSCs)定向分化为心肌样细胞的影响。方法采用全骨髓贴壁法从10只SD大鼠四肢骨中分离、培养BMSCs,流式细胞术对培养的细胞进行鉴定。对第2... 详细信息

目的探讨转化生长因子-β1(TGF-β1)与丹参酮ⅡA(tanshinoneⅡA)联合诱导对大鼠骨髓间充质干细胞(BMSCs)定向分化为心肌样细胞的影响。方法采用全骨髓贴壁法从10只SD大鼠四肢骨中分离、培养BMSCs,流式细胞术对培养的细胞进行鉴定。对第2代BMSCs作定向诱导,根据加入诱导剂的不同分为TGF-β1组、tanshinoneⅡA组、两者联合诱导组及实验对照组(不加任何诱导剂)。诱导72h后更换为常规培养基继续培养,相差显微镜观察培养细胞的形态学变化;各组培养4周后,应用免疫细胞化学染色法检测原肌球蛋白(TPM)、缝隙连接蛋白43(Cx43)以及心肌肌钙蛋白I(c Tn I)的表达情况;实时定量PCR(Real-time PCR)法检测各组BMSCs在诱导培养的第1、2、4周心肌早期转录因子GATA-4、Nkx2.5的表达情况;透射电子显微镜观察分化细胞的超微结构变化。结果实验对照组细胞TPM、Cx43及c Tn I均为弱阳性或阴性表达。与实验对照组相比,TGF-β1组、TanshinoneⅡA组及两者联合诱导组BMSCs以上各标记物的阳性表达均明显升高,差异均具有统计学意义(均P<0.05)。其中,两者联合诱导组各标记物的阳性表达均显著高于TGF-β1及TanshinoneⅡA单独诱导组。Real-time PCR结果显示,在诱导第1周时TGF-β1组、TanshinoneⅡA组及两者联合诱导组GATA-4及Nkx2.5基因表达均最强,随后表达减弱至不表达。1周时,联合诱导组GATA-4 mRNA相对表达量是实验对照组的3.7倍,Nkx2.5 mRNA相对表达量是实验对照组的2.9倍,差异均具有统计学意义(均P<0.05)。透射电子显微镜结果显示,各诱导组均可见分化的细胞呈杆状,胞核卵圆形,位于细胞中央,胞质中可见平行排列的肌丝、粗面内质网和线粒体等细胞器。结论 TGF-β1、tanshinoneⅡA均可分别及联合诱导BMSCs获得心肌分化表型,且两者联合诱导效果优于单一诱导。

关键词：骨髓间充质干细胞转化生长因子-β1 丹参酮ⅡA 心肌细胞流式细胞术免疫组织化学实时定量聚合酶链反应大鼠

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Solution‑Processed Thin Film Transparent Photovoltaics:Present Challenges and Future Development

引用

Nano-Micro Letters 2025年第2期17卷 566-600页

作者： Tianle liu Munerah M.S.Almutairi Jie Ma Aisling Stewart Zhaohui Xing Mengxia liu bo Hou Yuljae Cho UM-SJTU Joint Institute Shanghai Jiao Tong UniversityShanghai 200240People’s Republic of China School of Physics and Astronomy Cardiff UniversityCardiff CF243AAWalesUK Department of Electrical and Computer Engineering Yale UniversityNew HavenCT 06511USA Energy Sciences Institute Yale UniversityWest HavenCT 06516USA Future Photovoltaics Research Center Global Institute of Future TechnologyShanghai Jiao Tong UniversityShanghai 200240People’s Republic of China

Electrical energy is essential for modern society to sustain economic *** soaring demand for the electrical energy,together with an awareness of the environmental impact of fossil fuels,has been driving a shift towards the utilization of solar ***,traditional solar energy solutions often require extensive spaces for a panel installation,limiting their practicality in a dense urban *** overcome the spatial constraint,researchers have developed transparent photovoltaics(TPV),enabling windows and facades in vehicles and buildings to generate electric *** TPV advancements are focused on improving both transparency and power output to rival commercially available silicon solar *** this review,we first briefly introduce wavelength-and non-wavelengthselective strategies to achieve *** of merit and theoretical limits of TPVs are discussed to comprehensively understand the status of current TPV *** we highlight recent progress in different types of TPVs,with a particular focus on solution-processed thin-film photovoltaics(PVs),including colloidal quantum dot PVs,metal halide perovskite PVs and organic *** applications of TPVs are also reviewed,with emphasis on agrivoltaics,smart windows and ***,current challenges and future opportunities in TPV research are pointed out.

关键词： Transparent semiconductors Solution-processable transparent solar cell Emerging solar cell materials Buildingintegrated photovoltaics

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Antidepressant effects of the extract YZ-50 from Polygala tenuifolia in chronic mild stress treated rats and its possible mechanisms

Antidepressant effects of the extract YZ-50 from Polygala te...

引用

中国药理学会第十次全国学术会议

作者： HU Yuan,LIAO Hong-bo,liu ping,GUO Dai-hong (Dept of Clinical Pharmacology,Pharmacy Care Center,Chinese PLA General Hospital,Beijing 100853,P.R.China)

YZ-50 is a active fraction obtained from the root of Polygala tenuifolia Willd(Polygalaceae) extract and it has been reported previously to exert beneficial effects on mental health in depressed sufferers,however,its mechanism of action remains *** study utilized the chronic mild stress(CMS) model of depression in Sprague-Dawley rats to evaluate the effects of YZ-50 on depressive ***,we tested the hypothesis that the capacity of YZ-50 to reverse the harmful effects of CMS is relative to the hypothalamo-pituitary-adrenal (HPA) system and brain-derived neurotrophic factor(BDNF) in the *** administration of YZ- 50 for 28 days at the doses of 140 and 280 mg·kg in CMS,YZ-50 reversed the CMS-induced changes in sucrose consumption,plasma corticosterone levels and open field *** addition,CMS significantly decreased hippocampal BDNF mRNA levels,however,YZ-50 counteracted a decrease in hippocampal BDNF mRNA caused by *** conclusion,YZ-50 reversed the harmful effects of CMS on mood and behaviors in rats and it possesses an antidepressant property that is at least in part mediated by neuroendocrine and neuropropective systems,and it is likely that the HPA system plays an important role in this processes.

关键词：

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

AAV2-PDE6B restores retinal structure and function in the retinal degeneration 10 mouse model of retinitis pigmentosa by promoting phototransduction and inhibiting apoptosis

引用

Neural Regeneration Research 2025年第8期20卷 2408-2419页

作者： Ruiqi Qiu Mingzhu Yang Xiuxiu Jin Jingyang liu Weiping Wang Xiaoli Zhang Jinfeng Han bo Lei Henan Eye Hospital Henan Provincial People’s HospitalPeople’s Hospital of Zhengzhou UniversityZhengzhouHenan ProvinceChina Eye Institute Henan Academy of Innovations in Medical ScienceZhengzhouHenan ProvinceChina Branch of National Clinical Research Center for Ocular Disease Henan Provincial People’s HospitalZhengzhouHenan ProvinceChina Academy of Medical Science Zhengzhou UniversityZhengzhouHenan ProvinceChina

Retinitis pigmentosa is a group of inherited diseases that lead to retinal degeneration and photoreceptor cell ***,there is no effective treatment for retinitis pigmentosa caused by PDE6B ***-associated virus(AAV)-mediated gene therapy is a promising strategy for treating retinitis *** aim of this study was to explore the molecular mechanisms by which AAV2-PDE6B rescues retinal *** do this,we injected retinal degeneration 10(rd10)mice subretinally with AAV2-PDE6B and assessed the therapeutic effects on retinal function and structure using dark-and light-adapted electroretinogram,optical coherence tomography,and ***-independent acquisition-mass spectrometry-based proteomic analysis was conducted to investigate protein expression levels and pathway enrichment,and the results from this analysis were verified by real-time polymerase chain reaction and western ***2-PDE6B injection significantly upregulated PDE6βexpression,preserved electroretinogram responses,and preserved outer nuclear layer thickness in rd10 *** expressed proteins between wild-type and rd10 mice were closely related to visual perception,and treating rd10 mice with AAV2-PDE6B restored differentially expressed protein expression to levels similar to those seen in wild-type *** Encyclopedia of Genes and Genome analysis showed that the differentially expressed proteins whose expression was most significantly altered by AAV2-PDE6B injection were enriched in phototransduction ***,the phototransductionrelated proteins Pde6α,Rom1,Rho,Aldh1a1,and Rbp1 exhibited opposite expression patterns in rd10 mice with or without AAV2-PDE6B ***,Bax/Bcl-2,p-ERK/ERK,and p-c-Fos/c-Fos expression levels decreased in rd10 mice following AAV2-PDE6B *** data suggest that AAV2-PDE6B-mediated gene therapy promotes phototransduction and inhibits apoptosis by inhibiting the ERK signaling pathway and upr

关键词： apoptosis AAV2-PDE6B ERK1/2 gene therapy phototransduction proteomics rd10 retinitis pigmentosa

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

银杏叶提取物对糖尿病纤溶酶原激活物抑制物1及凝血噁烷B2影响

引用

中国新药与临床杂志 2004年第12期23卷 836-838页

作者：吴波韩萍刘英敏中国医科大学附属第二医院内分泌科辽宁沈阳110004

目的 :观察银杏叶提取物对 2型糖尿病病人纤溶酶原激活物抑制物 1(PAI 1)及凝血烷B2(TXB 2 )的影响。方法 :将 6 4名 2型糖尿病病人随机分为常规治疗组和银杏叶提取物治疗组各 32例 ,正常对照组 30例。银杏叶提取物治疗组在常规治疗... 详细信息

目的 :观察银杏叶提取物对 2型糖尿病病人纤溶酶原激活物抑制物 1(PAI 1)及凝血烷B2(TXB 2 )的影响。方法 :将 6 4名 2型糖尿病病人随机分为常规治疗组和银杏叶提取物治疗组各 32例 ,正常对照组 30例。银杏叶提取物治疗组在常规治疗基础上 ,予银杏叶提取物注射液 2 0mL +氯化钠注射液 2 5 0mL ,iv ,gtt ,qd。2 1d后检测空腹和餐后 2h血糖、空腹胰岛素 (FINS) ,PAI 1,TXB 2。结果 :银杏叶提取物治疗组血浆FINS ,PAI 1及TXB 2在治疗后显著下降 ,下降值分别为 (16±s 6 )mU·L- 1,(33± 6 ) μg·L- 1,(73± 12 )ng·L- 1(P <0 .0 1)。结论 :银杏叶提取物可以降低血浆FINS ,PAI 1及TXB 2的水平 ,对预防

关键词：糖尿病,非胰岛素依赖型纤溶酶原渤活物抑制物1 胰岛素凝血噁烷B2 银杏叶提取物

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：