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Effect of surface acidity and pore size of Al-substituted plugs-containing SBA-15 and MCM-41 silicas on the polymerization of THF

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Chinese Chemical Letters 2011年第1期22卷 105-108页

作者： Zhi Qi Jia Ming zhao chun Guang Gao Yong Xiang zhao School of Chemistry and Chemical Engineering Shanxi University Engineering Research Center for Fine Chemicals of Ministry of Education Taiyuan 030006 China

We reported here the simultaneous influence of surface acidity and pore size of M-substituted hexagonal mesoporous silicas （Al- doped plugs-containing SBA-15 and M-doped MCM-41） on polymerization of THE These materials were directly synthesized by introduced aluminum isopropoxide into reaction mixture including surfactant and siliceous precursor. Al-doped plugs-containing SBA-15 （denotes as PAS） samples not only possess typical two-step desorption isotherms, which implied PAS materials generated plugs in their mesochannel, but also exhibit larger pore size and thicker wall than that of Al-doped MCM-41 （denotes as ACM）, which implied PAS would have a great advantage on catalytic reaction involving large molecular （e.g. polymer of THF） in industrial point＇of view. To investigate catalytic activity of PAS and ACM with moderate acidic sites the polymerization of THF in the presence of acetic anhydride was carried out. The results showed PAS exhibiting good performance on polymerization of THF. Such result could be related to the large pore size and moderate acidic sites.

关键词： Hexagonal mesostructure Polymerization THF Acidity Pore size

可控转速机匣起始位置对跨声速压气机转子流动稳定性的影响

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工程热物理学报 2024年第5期45卷 1341-1349页

作者：赵佳诣吴宛洋钟兢军上海海事大学商船学院上海201306 上海电机学院机械学院上海201306

机匣处理的几何结构参数将对其扩稳机制和扩稳能力产生影响。本文针对可控转速机匣中可转动环段的起始位置对跨声速压气机转子流动稳定性的影响开展数值研究。结果表明,当可转动环段的起始位置从叶顶尾缘开始逐渐向上游移动的过程中,可... 详细信息

机匣处理的几何结构参数将对其扩稳机制和扩稳能力产生影响。本文针对可控转速机匣中可转动环段的起始位置对跨声速压气机转子流动稳定性的影响开展数值研究。结果表明,当可转动环段的起始位置从叶顶尾缘开始逐渐向上游移动的过程中,可转动环段作用范围的扩展使叶顶流场处于逆压流动的范围扩大,通流条件恶化,但由于同时也降低了叶尖负荷,稳定工作的流量范围得以扩大。而当起始位置继续向上游移动至20%轴向弦长和叶顶前缘处时,可转动环段能够分别完成对泄漏涡破碎后流体和来流主流的轴向加速,降低激波/泄漏涡干涉强度的同时削弱了堵塞效应,转子流动稳定性得到有效改善,特别是当起始位置位于叶顶前缘时,稳定工作裕度提高了52.56%。

关键词：可控转速机匣起始位置跨声速压气机转子叶顶泄漏流流动稳定性

平欧榛子副产物不同溶剂提取物的生物活性评价及超高效液相色谱-质谱分析

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食品科学 2024年第1期45卷 32-41页

作者：苏可欣赵玉红东北林业大学生命科学学院黑龙江哈尔滨150040 黑龙江省森林食品资源利用重点实验室黑龙江哈尔滨150040

采用不同极性溶剂(水、甲醇、80%乙醇溶液和乙酸乙酯)对平欧榛子的副产物(叶、果苞、壳、枝条和种皮)进行酚类物质提取,对其体外抗氧化、降血糖、抗炎活性进行评估,并利用超高效液相色谱-质谱(ultra-high performance liquid chromatogr... 详细信息

采用不同极性溶剂(水、甲醇、80%乙醇溶液和乙酸乙酯)对平欧榛子的副产物(叶、果苞、壳、枝条和种皮)进行酚类物质提取,对其体外抗氧化、降血糖、抗炎活性进行评估,并利用超高效液相色谱-质谱(ultra-high performance liquid chromatography-mass spectrometry,UPLC-MS)联用技术对其多酚类物质进行鉴定。榛子叶和枝条提取物比果苞、壳和种皮提取物具有更强的体外抗氧化、降血糖和抗炎活性,主要与榛子副产物中的总酚和原花青素相关,其中榛子枝条的甲醇提取物中总酚(以干质量中没食子酸质量计)和原花青素(以干质量中原花青素质量计)含量最高,分别为(37.13±0.22)mg/g和(2.27±0.04)mg/g,榛子叶的80%乙醇溶液提取物中的总黄酮(以干质量中芦丁质量计)含量最高,为(18.21±1.37)mg/g。乙酸乙酯提取物的总酚、总黄酮和原花青素含量在相同部位提取物中最低,但是对α-淀粉酶活性和脂氧合酶活性具有显著抑制能力(P<0.05),其中果苞的乙酸乙酯提取物抑制α-淀粉酶的效果最好,叶的乙酸乙酯提取物对脂氧合酶的抑制作用最强。经UPLC-MS分析可知,平欧榛子副产物中的酚类物质以黄酮类化合物居多,另外还含有萜类、生物碱、木脂素和有机酸等多种活性物质。平欧榛子副产物中的活性成分具有应用于功能食品或药品中的潜能。

关键词：平欧榛子副产物酚类物质生物活性主成分分析相关性分析

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极端气候变化对黄河源区生态系统的影响

科学技术与工程 2024年第26期24卷 11167-11179页

作者：刘宜浩丁圆圆赵健赟李国荣赵利江李启龙青海大学地质工程学院西宁810016 青海省基础测绘院西宁810001 青海省水利水电勘测设计研究院有限公司西宁810000

利用黄河源区1982—2020年逐日气温、降水数据和多源遥感数据分别构建26个极端气候指标以及生态环境质量综合评估体系,分析极端气候、生态环境质量的时空分布与变化特征,揭示极端气候变化对生态环境的影响机制。结果表明:研究区极端气... 详细信息

利用黄河源区1982—2020年逐日气温、降水数据和多源遥感数据分别构建26个极端气候指标以及生态环境质量综合评估体系,分析极端气候、生态环境质量的时空分布与变化特征,揭示极端气候变化对生态环境的影响机制。结果表明:研究区极端气温、降雨在波动上升,且均在西北—东南方向上呈现阶梯式变化规律;降水量由西北至东南逐渐增加,空间变化率在数值上多呈北高南低;冷(暖)夜的年际线性变化率分别大于冷(暖)昼且其空间变化趋势具有明显的区域差异性并且通过p<0.05的显著性检验;多年生态环境质量均值在0.51~0.73波动,从多年来的生态环境质量空间变化趋势上看,恶化与改善并存,其中北部的贵南、同德及玛多县一带退化较为明显,东南部多数地区有改善趋势;因子探测结果表明各极端气候驱动因子均通过了p=0.01显著性检验,其中水分对生态环境质量的空间分布具有更重要的主导作用,且因子之间的交互作用会增强对生态环境的影响作用。

关键词：极端气候指标生态环境质量评价地理探测器影响机制

Identification and characterization of human hematopoietic mesoderm

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Science China(Life Sciences) 2024年第2期67卷 320-331页

作者： Yuqi Wen Jingjing zhao Runqing Zhang Fan Liu Xiaoyuan Chen Dan Wu Mengge Wang Cuicui Liu Pei Su Panpan Meng Yiyue Zhang Xin Gao Lu Wang Hongtao Wang Jiaxi Zhou State Key Laboratory of Experimental Hematology National Clinical Research Center for Blood DiseasesHaihe Laboratory of Cell EcosystemInstitute of Hematology&Blood Diseases HospitalChinese Academy of Medical Sciences&Peking Union Medical CollegeTianjin 300020China Tianjin Institutes of Health Science Tianjin 301600China CAMS Center for Stem Cell Medicine PUMC Department of Stem Cell and Regenerative MedicineTianjin 300020China Division of Cell Developmental and Integrative BiologySchool of MedicineSouth China University of TechnologyGuangzhou 510006China

The embryonic mesoderm comprises heterogeneous cell subpopulations with distinct lineage *** is unclear whether a bias for the human hematopoietic lineage emerges at this early developmental *** this study,we integrated single-cell transcriptomic analyses of human mesoderm cells from embryonic stem cells and embryos,enabling us to identify and define the molecular features of human hematopoietic mesoderm(HM)cells biased towards hematopoietic *** discovered that BMP4 plays an essential role in HM specification and can serve as a marker for HM ***,BMP4 acts as a downstream target of HDAC1,which modulates the expression of BMP4 by deacetylating its *** of HDAC significantly enhances HM specification and promotes subsequent hematopoietic cell *** conclusion,our study identifies human HM cells and describes new mechanisms for human hematopoietic development.

关键词： hematopoietic mesoderm human pluripotent stem cells human embryos BMP4 HDAC1

光子Moiré超晶格薄膜的设计及光学特性研究

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光学学报 2024年第4期44卷 355-362页

作者：赵富源孙晓红郑州大学电气与信息工程学院河南省激光与光电信息技术重点实验室河南郑州450001

二维光子Moiré超晶格拥有一些常规光子晶体不具备的特性,例如平带特征和不同于安德森局域化的光局域现象。本文利用多光束干涉法构建二维光子Moiré超晶格结构,采用有限元法对其能带结构及光场特性进行研究。通过优化Moiré晶格厚度、... 详细信息

二维光子Moiré超晶格拥有一些常规光子晶体不具备的特性,例如平带特征和不同于安德森局域化的光局域现象。本文利用多光束干涉法构建二维光子Moiré超晶格结构,采用有限元法对其能带结构及光场特性进行研究。通过优化Moiré晶格厚度、空气孔半径对其平带及局域特性的影响,得到了高局域特性的Moiré晶格结构。研究中发现,正方晶格具有不同于六角晶格的准狄拉克锥光局域化效应。本文研究结果对发展高性能微纳结构器件具有重要参考价值。

关键词：光子晶体光子Moiré超晶格多光束干涉平带光局域

MDT理念下以“一站式”多学科诊治为目标的临床实习教学应用

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教育教学论坛 2024年第6期 145-148页

作者：李炯李午丽赵春晖安徽医科大学口腔医学院安徽合肥230032

在高素质口腔医学人才培养要求下,探讨MDT理念下以“一站式”多学科诊治为目标在临床本科生实习教学中的应用。与传统教学模式相比,分析学生在临床综合能力、学习兴趣、文献检索能力、知识理解和记忆等方面的改变。结合“以提升临床能... 详细信息

在高素质口腔医学人才培养要求下,探讨MDT理念下以“一站式”多学科诊治为目标在临床本科生实习教学中的应用。与传统教学模式相比,分析学生在临床综合能力、学习兴趣、文献检索能力、知识理解和记忆等方面的改变。结合“以提升临床能力为导向的互联网+模块教学法”及“标准化病人的教学考核模式”,强化了实习生的临床基本技能和临床思维能力,调动了其主动学习的积极性,奠定了学生成为具有职业胜任能力口腔医师的基础,进一步推动实习生向临床医生的转变,为优化临床实习效果提供了新思路。

关键词： MDT 一站式多学科综合科临床实习

Bi-level Optimal Planning of Voltage Regulator in Distribution Systems Considering Maximization of Incentive-based Photovoltaic Energy Integration

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CSEE Journal of Power and Energy Systems 2023年第6期9卷 2008-2017页

作者： Xu Xu Youwei Jia chun Sing Lai Minghao Wang zhao Xu Department of Electrical and Electronic Engineering Southern University of Science and TechnologyShenzhenChina Department of Electrical Engineering The Hong Kong Polytechnic UniversityHung HomHong Kong SARChina Department of Electrical and Electronic Engineering University Key Laboratory of Advanced Wireless Communications of Guangdong ProvinceSouthern University of Science and TechnologyShenzhen 515100China Department of Electronic and Computer Engineering Brunel Institute of Power SystemsBrunel University LondonLondonUB83PH United Kingdom Department of Electrical Engineering Shenzhen Research InstituteThe Hong Kong Polytechnic UniversityHung HomHong Kong SARChina

This paper focuses on optimal voltage regulator(VR)planning to maximize the photovoltaic(PV)energy integration in distribution *** describe the amount of dynamic PV energy that can be integrated into the power system,the concept of PV accommodation capability(PVAC)is introduced and modeled with *** proposed planning model is formulated as a Benders decomposition based bi-level stochastic optimization *** the upper-level problem,VR planning decisions and PVAC are determined via mixed integer linear programming(MILP)before considering *** in the lower-level problem,the feasibility of first-level results is checked by critical network constraints(*** magnitude constraints and line capacity constraints)under uncertainties considered by time-varying loads and PV *** this paper,these uncertainties are represented in the form of operational scenarios,which are generated by the Gaussian copula theory and reduced by a well-studied backward-reduction *** modified IEEE 33-node distribution grid is utilized to verify the effectiveness of the proposed *** results demonstrate that a PV energy integration can be significantly enhanced after optimal voltage regulator planning.

关键词： Bi-level stochastic optimization problem critical network constraints photovoltaic energy integration uncertainties voltage regulator planning

Cdc42 deletion yielded enamel defects by disrupting mitochondria and producing reactive oxygen species in dental epithelium

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Genes & Diseases 2024年第5期11卷 335-349页

作者： Jinxuan Zheng rongcheng Yu Yiqi Tang Sihui Su Sainan Wang Chenxi Liao Xuecong Li Jiabin Liao Dongsheng Yu Tingting Ai Wei zhao Vicky Yau Chufeng Liu Liping Wu Yang Cao Hospital of Stomatology Guanghua School of StomatologyGuangdong Provincial Key Laboratory of StomatologySun Yat-sen UniversityGuangzhouGuangdong 510055China Guangdong Provincial Key Laboratory of Oral Diseases GuangzhouGuangdong 510055China Department of Cariology and Endodontology Peking University School and Hospital of Stomatology&National Center for Stomatology&National Clinical Research Center for Oral Diseases&National Engineering Research Center of Oral Biomaterials and Digital Medical DevicesBeijing 100081China Department of Oral and Maxillofacial Surgery University at BuffaloBuffaloNY 14214USA Department of Orthodontics Stomatological HospitalSouthern Medical UniversityGuangzhouGuangdong 510280China

Developmental defects of enamel are common due to genetic and environmental factors before and after ***42,a Rho family small GTPase,regulates prenatal tooth development in ***,its role in postnatal tooth development,especially enamel formation,remains ***,we investigated Cdc42 functions in mouse enamel development and tooth repair after ***42 showed highly dynamic temporospatial patterns in the developing incisors,with robust expression in ameloblast and odontoblast ***,epithelium-specific Cdc42 deletion resulted in enamel defects in *** differentiation was inhibited,and hypomineralization of enamel was observed upon epithelial Cdc42 *** analysis showed that abnormal mitochondrial components,phosphotransferase activity,and ion channel regulator activity occurred in the Cdc42 mutant dental *** oxygen species accumulation was detected in the mutant mice,suggesting that abnormal oxidative stress occurred after Cdc42 ***,Cdc42 mutant mice showed delayed tooth repair and generated less calcified *** dysfunction and abnormal oxygen consumption were evidenced by reduced Apool and Timm8a1 expression,increased Atp5j2 levels,and reactive oxygen species overproduction in the mutant repair ***-specific Cdc42 deletion attenuated ERK1/2 signaling in the labial cervical *** Sox2 expression in the mutant labial cervical loop after clipping might lead to delayed tooth *** findings suggested that mitochondrial dysfunction,up-regulated oxidative stress,and abnormal ion channel activity may be among multiple factors responsible for the observed enamel defects in Cdc42 mutant ***,Cdc42 exerts multidimensional and pivotal roles in enamel development and is particularly required for ameloblast differentiation and enamel matrix formation.

关键词： Cdc42 Enamel defects Mitochondrial dysfunction Rho GTPase Tooth repair