检索结果-南通市图书馆

Immobilizing Triphenylamine with Photoredox Inert Sr^(2+)Forming Sr-MOF with Controlled Electron Migration for Photocatalytic Oxidation of Thiols to Disulfides

引用

Chinese Journal of Chemistry 2024年第10期42卷 1093-1099页

作者： Ying-Xia Wang Fang Zheng Dong-Xia Song Bao-Yue Niu Lu-qian deng Xian-Ming Zhang Key Laboratory of Magnetic Molecules and Magnetic Information Materials(Ministry of Education) Schoolof Chemistry and Materials ScienceShanxi Normal UniversityTaiyuanShanxi 030006China Key Laboratory of Interface Science and Engineering in Advanced Material(Ministry of Education) College of ChemistryTaiyuan University of TechnologyTaiyuanShanxi 030024China

The photocatalytic oxidative coupling of thiols is one of the most popular methods to synthesize the disulfides.Triphenylamine and its derivatives(TPAs)are promising for the above reaction,but suffer from the easy polymerization and difficult separation.To overcome these obstacles while controlling the photogenerated electrons transfer directly to target substrates,herein,we constructed one TPA-based metal-organic framework(MOF),(Me_(2)NH_(2))[Sr(TCBPA)]·DMA·3H_(2)O(1),by direct self-assembly of tris(4′-carboxybiphenyl)amine(H_(3)TCBPA)and photoredox inert strontium ion(Sr^(2+)).DFT calculations revealed that the valence band maximum(VBM)and the conduction band minimum(CBM)are mainly located on TCBPA^(3-),successfully inhibiting the undesirable electron migration to metal nodes.Experimental results indicated that 1 displays superior performance than homogeneous H_(3)TCBPA,which may result from the abundant π…π and C—H…π interactions between the well-arranged TCBPA^(3-)and the build-in electric field between the anionic framework and the Me_(2)NH^(2+).This work highlights that immobilizing TPAs into MOFs is one promising approach to designing heterogeneous photocatalysts for the synthesis of disulfides by oxidative coupling of thiols.

关键词： Triphenylamine Metal-organic frameworks Strontium Photooxidation Thiols Disulfides

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Distribution and geochemical significance of trace elements in kerogens from Ediacaran–Lower Cambrian strata in South China

引用

Acta Geochimica 2023年第1期42卷 50-62页

作者： qian deng Guanyu Zhao Haozhe Wang Bin Cheng Zewen Liao State Key Laboratory of Organic Geochemistry Guangzhou Institute of GeochemistryChinese Academy of SciencesGuangzhou 510640China CAS Center for Excellence in Deep Earth Science Guangzhou 510640China University of Chinese Academy of Sciences Beijing 100049China

Some trace elements(TEs),both bio-essential and redox-sensitive,are promising tracers of Earth’s surface processes.As an essential sedimentary organic matter,kerogen may have inherited and retained the key TEs from organisms.In this study,the distribution of TEs in kerogens from two sections(Dongkanshang and Fengtan) in South China was analyzed to explore its biogeochemical significance during Ediacaran-Lower Cambrian.Compared with V and Zn,the relative concentrations of Co,Ni,Cu,and Mo were generally higher in kerogens than in the whole rocks.Enrichment of TEs in the kerogen was involved in the selective utilization of TEs by different organic precursors and the competition of sulfide in the depositional environment.The significant content of TEs in the kerogens from deep-water facies corresponded to a more negative δ^(13) Ckeras a result of the dominant taxa of chemo autotrophs with tremendous bioaccumulation potential for trace metals and the reduction conditions favorable for organic matter preservation.Furthermore,the content variations of trace elements in the kerogens coincided with the rise and fall of the Ediacaran biota,implying that the trace elements might have played an important role in early life evolution.

关键词： Trace elements Kerogen Ediacaran-Early Cambrian Biogeochemical significance South China

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

Annealing engineering induced high thermoelectric performance in Yb-filled CoSb_(3) skutterudites

引用

Journal of Materials Science & Technology 2023年第19期150卷 168-174页

作者： Haoran Feng qian deng Yan Zhong Xuri Rao Yadong Wang Jianglong Zhu Fujie Zhang Ran Ang Key Laboratory of Radiation Physics and Technology Ministry of EducationInstitute of Nuclear Science and TechnologySichuan UniversityChengdu 610064China Institute of New Energy and Low-Carbon Technology Sichuan UniversityChengdu 610065China

The great pressure of energy shortage has made CoSb_(3) materials with excellent mechanical stability in the mid-temperature region favored for the integration of thermoelectric devices.However,their ex-cessive lattice thermal conductivity and poor Seebeck coefficient lead to low energy conversion effi-ciency.Filling Yb into the lattice void to optimize the band structure and regulate the chemical po-tential is an indispensable means for improving the thermoelectric properties of CoSb_(3)-based materials,while the phase structure and thermoelectric properties vary with the preparation process.This motivates the current work to focus on the influence of annealing temperature on the microstructure and thermoelectric properties of Yb-filled CoSb_(3).Experimental analysis and theoretical model eluci-dated that an increase in annealing temperature can optimize the Yb filling fraction,which simulta-neously manipulates the band structure as well as chemical potential,resulting in an excellent electrical property.Furthermore,the phase and microstructure characterization clarify that the annealing temperature can effectively affect the grain size.The complex grain boundary induced by grain refinement,more filled Yb atoms and precipitates strongly scatter wide-frequency phonons,significantly suppressing the lattice thermal conductivity.As a result,a superior dimensionless figure of merit(ZT)value of~1.33 at 823 K and an average ZTave of~0.9(323-823 K)were achieved in the Ybo.4Co4Sb12 sample annealed at 923 K,and the calculated conversion efficiency could reach~13%.This work pro-vides a unique paradigm to improve thermoelectrics in the filled CoSb_(3)-based skutterudites by annealing engineering.

关键词： CoSb_(3)skutterudite Annealing engineering Grain refinement Phonon scattering Thermoelectric optimization

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

AutoQNN: An End-to-End Framework for Automatically Quantizing Neural Networks

引用

Journal of Computer Science & Technology 2024年第2期39卷 401-420页

作者：龚成卢冶代素蓉邓倩杜承昆李涛 College of Software Nankai UniversityTianjin 300350China College of Computer Science Nankai UniversityTianjin 300350China State Key Laboratory of Processors Institute of Computing TechnologyChinese Academy of Sciences Beijing 100190China

Exploring the expected quantizing scheme with suitable mixed-precision policy is the key to compress deep neural networks(DNNs)in high efficiency and accuracy.This exploration implies heavy workloads for domain experts,and an automatic compression method is needed.However,the huge search space of the automatic method introduces plenty of computing budgets that make the automatic process challenging to be applied in real scenarios.In this paper,we propose an end-to-end framework named AutoQNN,for automatically quantizing different layers utilizing different schemes and bitwidths without any human labor.AutoQNN can seek desirable quantizing schemes and mixed-precision policies for mainstream DNN models efficiently by involving three techniques:quantizing scheme search(QSS),quantizing precision learning(QPL),and quantized architecture generation(QAG).QSS introduces five quantizing schemes and defines three new schemes as a candidate set for scheme search,and then uses the Differentiable Neural Architecture Search(DNAS)algorithm to seek the layer-or model-desired scheme from the set.QPL is the first method to learn mixed-precision policies by reparameterizing the bitwidths of quantizing schemes,to the best of our knowledge.QPL optimizes both classification loss and precision loss of DNNs efficiently and obtains the relatively optimal mixed-precision model within limited model size and memory footprint.QAG is designed to convert arbitrary architectures into corresponding quantized ones without manual intervention,to facilitate end-to-end neural network quantization.We have implemented AutoQNN and integrated it into Keras.Extensive experiments demonstrate that AutoQNN can consistently outperform state-of-the-art quantization.For 2-bit weight and activation of AlexNet and ResNet18,AutoQNN can achieve the accuracy results of 59.75%and 68.86%,respectively,and obtain accuracy improvements by up to 1.65%and 1.74%,respectively,compared with state-of-the-art methods.Especially,compared with the full-precision AlexNet and ResN

关键词： automatic quantization mixed precision quantizing scheme search quantizing precision learning quan-tized architecture generation

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Inverse-designed Jones matrix metasurfaces for high-performance meta-polarizers

引用

Chinese Optics Letters 2024年第2期22卷 192-199页

作者：王志强李枫竣邓倩媚万舟李向平邓子岚 Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications Institute of Photonics TechnologyJinan UniversityGuangzhou 510632China

Polarizers have always been an important optical component for optical engineering and have played an indispensable part of polarization imaging systems.Metasurface polarizers provide an excellent platform to achieve miniaturization,high resolution,and low cost of polarization imaging systems.Here,we proposed freeform metasurface polarizers derived by adjoint-based inverse design of a full-Jones matrix with gradient-descent optimization.We designed multiple freeform polarizers with different filtered states of polarization(SOPs),including circular polarizers,elliptical polarizers,and linear polarizers that could cover the full Poincarésphere.Note that near-unitary polarization dichroism and the ultrahigh polarization extinction ratio(ER)reaching 50 d B were achieved for optimized circular polarizers.The multiple freeform polarizers with filtered polarization state locating at four vertices of an inscribed regular tetrahedron of the Poincarésphere are designed to form a full-Stokes parameters micropolarizer array.Our work provides a novel approach,we believe,for the design of meta-polarizers that may have potential applications in polarization imaging,polarization detection,and communication.

关键词： metasurface inverse design Jones matrix polarization imaging

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

Heterologous expression of Avermectins biosynthetic gene cluster by construction of a Bacterial Artificial Chromosome library of the producers

引用

Synthetic and Systems Biotechnology 2017年第1期2卷 59-64页

作者： qian deng Li Zhou Meizhong Luo Zixin deng Changming Zhao Key Laboratory of Combinatorial Biosynthesis and Drug Discovery Ministry of Educationand School of Pharmaceutical SciencesWuhan UniversityWuhan430071China College of Life Science and Technology Huazhong Agricultural UniversityWuhan430073China

Avermectins,a group of polyketide natural products,are widely used as anthelmintics in agriculture.Metabolic engineering and combinatorial biosynthesis were extensively employed to improve Avermectins production and create novel Avermectin derivatives,including Ivermectin and Doramectin.It is labor intensive and time cost to genetically manipulate Avermectins producer Streptomyces avermitilis in vivo.Cloning and heterologous expression of Avermectins biosynthetic gene cluster will make it possible to tailor the cluster in vitro.We constructed a Bacterial Artificial Chromosome(BAC)library of S.avermitilis ATCC 31267 with inserted DNA fragments ranged from 100 to 130 Kb.Five recombinant BAC clones which carried the Avermectins biosynthetic gene cluster ave(81 Kb in size)were screened out from the library.Then,ave was hetero-expressed in S.lividans.Three Avermectin components,A2a,B1a and A1a were detected from the cell extracts of recombinant strains.It will facilitate the development of Avermectin derivatives by polyketide synthase domain swapping and provide functional element for Avermectins synthetic biology study.

关键词： Streptomyces Avermectin BAC library Heterologous expression

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Streptomyces avermitilis industrial strain as cell factory for Ivermectin B1a production

引用

Synthetic and Systems Biotechnology 2019年第1期4卷 34-39页

作者： qian deng Liqiongzi Xiao Yang Liu Lixin Zhang Zixin deng Changming Zhao Key Laboratory of Combinatorial Biosynthesis and Drug Discovery Ministry of EducationSchool of Pharmaceutical SciencesWuhan UniversityWuhanChina State Key Laboratory of Bioreactor Engineering East China University of Science and TechnologyShanghaiChina

Ivermectin,a kind of valuable derivatives of Avermectin,is distinct from Avermectin due to the saturated bond at C22eC23 position.Combinatorial biosynthesis of Ivermectins based on Avermectins biosynthetic gene cluster(ave)has been achieved recently,while the establishment of an Ivermectin homogeneous component producing strain is challenging because of the limited compatibility between the native and heterologous polyketide synthase(PKS)domains.In this study,the PKS module 2 Dehydratase(DH)-Enoylreductase(ER)-Ketoreductase(KR)domain set of Meilingmycin,which is another naturally occurring homologue of Avermectin,was employed to substitute the DH-KR domains of Avermectins PKS module 2 to generate an Ivermectin biosynthetic gene cluster(ive).Ivermectins B1a and A1a were heterologously biosynthesized in a classic actinomyces host Streptomyces lividans.The Avermectin B1a high-producing strain S.avermitilis 3-115 was genetically engineered to give an artificial host cell and Ivermectin B1a single component was effectively produced with a production of 1.25±0.14 g/L.

关键词： Avermectin Ivermectin Meilingmycin Domain swapping Heterologo-us biosynthesis

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Wnt/Glycogen Synthase Kinase 3β/β-catenin Signaling Activation Mediated Sevoflurane Preconditioning-induced Cardioprotection

引用

Chinese Medical Journal 2015年第17期128卷 2346-2353页

作者： Jin-Dong Liu qian deng Huan-Huan Tian Yun-Ting Pang Gan-Lin deng Department of Anesthesiology The Affiliated Hospital of Xuzhou Medical College Jiangsu Province Key Laboratory of Anesthesiology Xuzhou Medical College Xuzhou Jiangsu 221004 China Jiangsu Province Key Laboratory of Anesthesiology Xuzhou Medical College Xuzhou Jiangsu 221004 China

Background： Sevoflurane preconditioning （SP） has been shown to invoke potent myocardial protection in animal studies and clinical trials. However, the mechanisms underlying SP are complex and not yet well understood. We investigated the hypothesis that the cardioprotection afforded by SP is mediated via the Writ/glycogen synthase kinase 3β（GSK3β）/β-catenin signaling pathway. Methods： Two models were established： A Langendorffperfused rat heart model and the H9C2 cell hypoxia/reoxygenation model. Both rats and H9C2 cells were randomly divided into 6 groups as follows： S group, ischemia-reperfusion （I/R） group, DMSO group, IWP group, SP group, and SP ＋ IWP group. Hemodynamic parameters, lactate dehydrogenase （LDH） activity in coronary effluent and cell culture supernatant, and the infarct size were measured to evaluate myocardial ischemia-reperfusion injuries. To determine the activity of Wnt/GSK3β/β-catenin signaling pathway, the expressions of Wnt3a, phospho-GSK3β, and β-catenin were measured by Western blotting. Results： SP improved cardiac function recovery, reduced infarct size （18 ±2% in the SP group compared with 35 ± 4% in the 1/R group; P 〈 0.05）, decreased LDH activity in coronary effluent, and culture supematant. IWP-2, an inhibitor of Wnt, abolished the cardioprotection by SR In addition, Western blotting analysis demonstrated that the expressions of Wnt3a, phospho-GSK3β, and β-catenin significantly （P 〈 0.05） increased in the I/R group, compared with the S group; and compared to I/R group, SP significantly （P 〈 0.05） increased Wnt3a, phospho-GSK3 β, and β-catenin expressions. Pretreatment with IWP-2 significantly （P 〈 0.05） abolished SP-induced Wnt/GSK3β/β-catenin signaling activation. Conclusions： The results showed for the first time that cardioprotection afforded by SP may be mediated partly via the Wnt/GSK3β/β-catenin signaling pathway.

关键词： Cardioprotection Ischemia-reperfusion Injury Preconditioning Sevoflurane Wnt/Glycogen Synthase Kinase3β/β-catenin Signaling

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

睡眠时长和睡眠质量在农村老人体力活动和认知功能间的中介作用

引用

现代预防医学 2024年第7期51卷 1244-1248页

作者：邓倩周峻民四川大学华西公共卫生学院/华西第四医院

目的分析睡眠时长和睡眠质量在成都市农村老年居民的体力活动水平和认知功能间的中介作用。方法采用多阶段随机抽样法，于2020年10月在成都市农村地区招募年满60岁的研究对象。本研究共纳入研究对象732名。采用老年人体力活动量表（ph... 详细信息

目的分析睡眠时长和睡眠质量在成都市农村老年居民的体力活动水平和认知功能间的中介作用。方法采用多阶段随机抽样法，于2020年10月在成都市农村地区招募年满60岁的研究对象。本研究共纳入研究对象732名。采用老年人体力活动量表（physical activity scale for the elderly）、认知状况电话访谈问卷（telephone interview for cognitive status）等工具进行问卷调查。采用线性回归模型分析体力活动水平对认知功能的影响，采用中介软件包（mediation package）探究睡眠时长和睡眠质量的中介作用。结果体力活动对认知功能具有正向影响（β=0.004,P<0.01）；睡眠时长在体力活动与认知功能间存在部分中介效应（P<0.05），中介效应为0.000 4，总效应为0.004 1，中介效应占比7.74%；睡眠质量在体力活动与认知功能间存在部分中介效应（P<0.01），中介效应为0.000 9，总效应为0.003 6，中介效应占比19.18%。结论为了预防和延缓认知功能下降，农村老年居民应坚持参加体力活动，且有必要开展针对其睡眠时长和睡眠质量的干预项目，促进其认知功能的改善。

关键词：体力活动认知功能睡眠时长睡眠质量中介效应

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Pim-1 Kinase Regulating Dynamics Related Protein 1 Mediates Sevoflurane Postconditioning-induced Cardioprotection

引用

Chinese Medical Journal 2017年第3期130卷 309-317页

作者： Jin-Dong Liu Hui-Juan Chen Da-Liang Wang Hui Wang qian deng Department of Anesthesiology The Affiliated Hospital of Xuzhou Medical University Jiangsu Province Key Laboratory of Anesthesiology Xuzhou Medical University Xuzhou Jiangsu 221004 China Department of Anesthesiology Jiangsu Province Key Laboratory of Anesthesiology Xuzhou Medical University Xuzhou Jiangsu 221004 China

Background： It is well documented that sevoflurane postconditioning （SP） has a significant myocardial protection effect. However, the mechanisms underlying SP are still unclear. In the present study, we investigated the hypothesis that the Pim-1 kinase played a key role in SP-induced cardioprotection by regulating dynamics-related protein 1 （Drpl）. Methods： A Langendorff model was used in this study. Seventy-two rats were randomly assigned into six groups as follows： CON group, ischemia reperfusion （I/R） group, SP group, SP＋proto-oncogene serine/threonine-protein kinase 1 （Pim-1） inhibitor II group, SP＋dimethylsufoxide group, and Pim- 1 inhibitor II group （n = 12, each）. Hemodynamic parameters and infarct size were measured to reflect the extent of myocardial 1/R injury. The expressions ofPim-1, B-cell leukemia/lymphoma 2 （Bcl-2） and cytochrome C （Cyt C） in cytoplasm and mitochondria, the Drp 1 in mitochondria, and the total Drp I and p-Drp I^sor637 were measured by Western blotting. In addition, transmission electron microscope was used to observe mitochondrial morphology. The experiment began in October 2014 and continued until July 2016. Results： SP improved myocardial I/R injury-induced hemodynamic parametric changes, cardiac function, and preserved mitochondrial phenotype and decreased myocardial infarct size （24.49 ± 1.72% in Sev group compared with 41.98 ± 4.37% in I/R group; P 〈 0.05）. However, Pim-1 inhibitor II significantly （P 〈 0.05） abolished the protective effect of SP. Western blotting analysis demonstrated that, compared with I/R group, the expression of Pim-1 and Bcl-2 in cytoplasm and mitochondria as well as the total p-Drplset637 in Sev group （P 〈 0.05） were upregulated. Meanwhile, SP inhibited Drp 1 compartmentalization to the mitochondria followed by a reduction in the release ofCyt C. Pretreatment with Pim- 1 inhibitor II significantly （P 〈 0.05） abolished SP-induced Pim- 1/p-Drp 1^ser637 signaling activation. Conclusions： These findings suggested that SP could attenuate myocardial ischemia-

关键词： Cardioprotection Ischemia-reperfusion Injury Mitochondria Pim-1 Postconditioning Sevoflurane

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：