检索结果-南通市图书馆

silylamido supported dinitrogen heterobimetallic complexes: syntheses and their catalytic ability

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

National Science Review 2021年第12期8卷 29-36页

作者： Dan-dan Zhai si-jun xie Yi Xia Hua-yi Fang Zhang-jie Shi Department of Chemistry Fudan University State Key Laboratory of Organometallic Chemistry Shanghai Institute of Organic ChemistryChinese Academy of Sciences

Molybdenum dinitrogen complexes supported by monodentate arylsilylamido ligand,[Ar(Mesi)N]MoNMg(THF)[N(siMe)Ar](5) and [Ar(Mesi)N]MoNsiMe(6)(Ar=3,5-MeCH) were synthesized and structurally characterized,and proved to be effective catalysts for the disproportionation of cyclohexadienes and isomerization of terminal alkenes.The~1 H NMR spectrum suggested that the bridging nitrogen ligand remains intact during the catalytic reaction,indicating possible catalytic ability of the Mo-N=N motif.

关键词： dinitrogen fixation dinitrogen-metal complex catalytic ability disproportionation isomerization

A mixed-valent high spin(μ-hydroxo)dicobalt(Ⅱ/Ⅲ) complex and its end-on type dioxygen adduct: synthesis, geometric and electronic structure studies

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China Chemistry 2021年第10期64卷 1693-1697页

作者： Ceng-Ceng Du si-jun xie Dan-Dan Zhai Zhang-Jie Shi Huayi Fang Department of Chemistry Fudan UniversityShanghai 200433China School of Materials Science and Engineering Tianjin Key Lab for Rare Earth Materials and ApplicationsNankai UniversityTianjin 300350China

A mixed-valent high spin (μ-hydroxo)dicobalt(Ⅱ/Ⅲ) complex bearing N,N′-bis(5-tertbutylsalicylidene)-1,2-diaminobenzene(Salophen^(tBu)) ligand was synthesized by reacting (Salophen^(tBu))Co(Ⅱ)(Py) with O_(2) at low temperature.This complex was isolated and structurally characterized by single crystal X-ray diffraction and infrared spectrum.Magnetic measurement showed a quartet ground state for this complex at room temperature,which was also supported by electron paramagnetic resonance (EPR)characterization.Computational investigations indicated the deviation of the equatorial N_(2)O_(2) coordination geometry around the Co(Ⅱ) center from plane stabilized the quartet state.The end-on type O_(2) adduct of this (μ-hydroxo)dicobalt(Ⅱ/Ⅲ) complex was isolated as dark-brown crystals and structurally and spectroscopically characterized.EPR measurement of this compound in solid state at room temperature presented an isotropic singlet at g~2,revealing the superoxide-like electronic feature of the coordinated O_(2) and was in line with the calculation results.The reactivity of the Co(Ⅲ)-O_(2) complex with N-hydroxyphthalimide,which can act as hydrogen atom donor,was also examined.

关键词： dicobalt complex mixed-valent electronic structure dioxygen adduct

Association between inflammatory bowel disease and all-cause dementia:A two-sample Mendelian randomization study

在线全文

学校读者我要写书评

暂无评论

World Journal of Psychiatry 2024年第1期14卷 15-25页

作者： Ou-Lan Liao si-Yuan xie jun Ye Qin Du Guo-Chun Lou Department of Gastroenterology The Second Affiliated HospitalZhejiang University School of MedicineHangzhou 310009Zhejiang ProvinceChina Department of Gastroenterology The Fourth Affiliated HospitalZhejiang University School of MedicineYiwu 322000Zhejiang ProvinceChina

BACKGROUND Numerous observational studies have documented a correlation between inflammatory bowel disease(IBD)and an increased risk of dementia.However,the causality of their associations remains elusive.AIM To assess the causal relationship between IBD and the occurrence of all-cause dementia using the two-sample Mendelian randomization(MR)method.METHODS Genetic variants extracted from the large genome-wide association study(GWAS)for IBD(the International IBD Genetics Consortium,n=34652)were used to identify the causal link between IBD and dementia(FinnGen,n=306102).The results of the study were validated via another IBD GWAS(United Kingdom Biobank,n=463372).Moreover,MR egger intercept,MR pleiotropy residual sum and outlier,and Cochran's Q test were employed to evaluate pleiotropy and heterogeneity.Finally,multiple MR methods were performed to estimate the effects of genetically predicted IBD on dementia,with the inverse variance weighted approach adopted as the primary analysis.RESULTS The results of the pleiotropy and heterogeneity tests revealed an absence of significant pleiotropic effects or heterogeneity across all genetic variants in outcome GWAS.No evidence of a causal effect between IBD and the risk of dementia was identified in the inverse variance weighted[odds ratio(OR)=0.980,95%CI:0.942-1.020,P value=0.325],weighted median(OR=0.964,95%CI:0.914-1.017,P value=0.180),and MR-Egger(OR=0.963,95%CI:0.867-1.070,P value=0.492)approaches.Consistent results were observed in validation analyses.Reverse MR analysis also showed no effect of dementia on the development of IBD.Furthermore,MR analysis suggested that IBD and its subtypes did not causally affect allcause dementia and its four subtypes,including dementia in Alzheimer's disease,vascular dementia,dementia in other diseases classified elsewhere,and unspecified dementia.CONCLUsiON Taken together,our MR study signaled that IBD and its subentities were not genetically associated with all-cause dementia or its subtypes.Further large prospective studies are w

关键词： Inflammatory bowel disease All-cause dementia Mendelian randomization Causal effect Risk factor©The

Metallothionein 1E Alleviates Cadmium-induced Renal Cytotoxicity through Promoting Mitochondrial Functional Recovery

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Biomedical and Environmental Sciences 2024年第1期37卷 117-121页

作者： WEN si Hui LI Lu Bei HUANG Hui Dan xie Ying LUO Lei Key Laboratory of Molecular Epidemiology of Hunan Province School of MedicineHunan Normal UniversityChangsha 410081HunanChina Department of Occupational Health Changsha Centre for Disease Control and PreventionChangsha 410004HunanChina The Key Laboratory of Model Animals and Stem Cell Biology in Hunan Province Hunan Normal University School of MedicineChangsha 410013HunanChina

The pervasive utilization of industrial substances has escalated human exposure to cadmium(Cd),a metal associated with long-term negative health outcomes such as renal dysfunction,neurological disorders,and various cancers^([1]).Once ingested by humans,Cd interacts with cysteine-rich metallothioneins(MTs)which have metal-binding and antioxidant properties and is subsequently transported to the kidney^([2]).

关键词： Renal kidney cadmium

Investigation on the influence of vortex generator on particle resuspension

在线全文

学校读者我要写书评

暂无评论

Particuology 2024年第3期86卷 126-136页

作者： Dongchi Yu jun-Li Lin Jin-Han xie ASML 80W Tasman DrSan Jose95134CaliforniaUSA Department of Mechanics and Engineering Science at College of Engineering and State Key Laboratory for Turbulence and Complex Systems Peking UniversityBeijing100081China

The vortex generator(VG)and its well-known effect in flow optimization are widely studied and employed across different engineering sectors.However,while the same working principles of VG may be well suited for the applications on surface-cleaning technologies,such promising potential is hardly,if any,explored in the published literature.Therefore,in the present study,the influence on flow-induced particle resuspension brought by a rectangular vG in a channel flow is investigated with the help of highfidelity computational fluid dynamics simulations.Substantial increases of particle removal forces and resuspension rates are discovered in long,strip-like regions with reduced boundary-layer thickness resulted from the vG-induced vortices,and the enhancement effect is especially significant for configurations with the VG installed at a greater angle of attack.It is also shown that while the resuspension enhancements on the lower and the upper surfaces of the channel exhibit distinct statistical characteristics,having a VG in the channel improves the overall particle-removing capability of the channel flow by introducing higher surface-averaged removal forces and particle resuspension rates.Last but not least,the increase of resuspension rate is especially significant for the smaller,micron-scale particles which are otherwise hardly disturbed by a VG-less channel flow,and such resuspension-enhancement effectgenerally subsides with increasing particle size.

关键词： Particle resuspension Vortexgenerator CFD Surface cleaning

Influence characteristics of water penetration on fibre-reinforced polymer/rigid polyurethane foam interface of the composite cross-arm considering natural ageing

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

High Voltage 2024年第1期9卷 81-93页

作者： jun xie Zhe Zhou Ziqian Liu Haonan Tian sigang Zhang Qing xie Hebei Provincial Key Laboratory of Power Transmission Equipment Security Defense North China Electric Power UniversityBaodingChina State Grid Gansu Electric Power Company LanzhouChina

Fibre-reinforced polymer(FRP)/rigid polyurethane foam(RPUF)interface is susceptible to moisture intrusion in addition to natural ageing during operation.This study investigated the influence of moisture intrusion on the FRP/RPUF interface under natural ageing using experiments and molecular dynamics(MD)simulations.Water absorption,shear strength,and leakage current tests were used to clarify the changes in the interface performance.The degradation mechanism of moisture intrusion at the interface under natural ageing was revealed by MD simulation and micro-characterisation.The results show that the natural ageing of interfacial materials will slightly reduce the quality of the interface but will reduce the water resistance of the material and promote the process of water intrusion into the interface.In addition,water mainly invades the interface through RPUF.After water penetration,the interfacial bonding strength and insulation performance significantly decreased.Plasticisation and hydrolysis of interfacial materials are the main reasons for decreased interfacial adhesion.Hydrolysis can cause irreversible damage to the interface,increasing interface defects and water absorption.The vicious cycle of material hydrolysis is the ultimate cause of interfacial debonding.The polar molecules produced by this process and the water absorbed by the interface caused the degradation of the interface insulation performance.

关键词： interface polyurethane interfacial

Existence of Positive Solutions to a Fractional-Kirchhoff System

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae sinica 2024年第1期40卷 225-240页

作者： Peng-fei Li jun-hui xie Dan Mu School of Mathematics and Statistics Hubei Minzu UniversityEnshi445000China

LetΩbe a bounded smooth domain in RN(N≥3).Assuming that 00 are constants,we consider the existence results for positive solutions of a class of fractional elliptic system below,{(a+b[u]^(2)_(s))(-Δ)^(s)u=vp+h_(1)(x,u,v,▽u,▽v),x∈Ω,(-Δ)^(s)v=u^(q)+h_(2)(x,u,▽,▽u,▽v),x∈Q,u,v>0,x∈Ω,u=v=0,x∈RN\Ω.Under some assumptions of hi(x,u,v,▽u,▽v)(i=1,2),we get a priori bounds of the positive solutions to the problem(1.1)by the blow-up methods and rescaling argument.Based on these estimates and degree theory,we establish the existence of positive solutions to problem(1.1).

关键词： fractional-Kirchhoff system a priori bounds degree theory positive solution

Metallogenesis of the Baidi Au-Sb deposit, southwest Guizhou Province, China: mineralogical and geochemical evidence from sulfur-bearing minerals

在线全文

学校读者我要写书评

暂无评论

Acta Geochimica 2024年第2期43卷 199-213页

作者： jun Yan Yong Xia Qinping Tan Zhuojun xie Guosong Ji State KeyLaboratory of Ore Deposit Geochemistry Institute of GeochemistryChineseAcademy of SciencesGuiyang 550081China Guizhou InstituteofTechnology Guiyang550003China No.102 GeologicalTeam Guizhou Bureau of Geologyand Mineral Exploration&DevelopmentZunyi563003China

The Baidi Au-Sb deposit, which contains 8 t of Au and 10,979 Mt of Sb, is a typical and rare paragenetic deposit located in southwestern Guizhou Province, China.Previous studies have focused on individual ores, but have not combined them to identify their paragenetic mechanism or metallogenic regularity. Therefore, we used field investigations, microscopic observations, and in situ analyses to identify the spatial distribution, mineral paragenesis, compositional evolution, and metallogenic material sources of the ore bodies. We also determined the Au and Sb paragenetic characteristics and the metallogenesis of the deposit. The main Au-bearing minerals in the deposit were early(Apy1–2) and late(Apy3) stage arsenopyrites, as well as pre-mineralization(Py1), mineralization(Py2–5), and late mineralization(Py6–7) stage pyrites. The main Sb-bearing minerals were stibnite(Snt), skinnerite, bournonite,and valentinite. The minerals formed in the order of Py1,Py2–3 + Apy1, Py4–5 + Apy2, Snt, and Py6–7 + Apy3.The δ34S values of the arsenopyrites and pyrites ranged from-5 to 5‰, while those of stibnite were mostly less than-5‰ in the later mineralization stages. Sulfur was provided by deep magmatic hydrothermal fluids, but sedimentary sulfur was added in the later stages. Moreover,the trace elemental contents fluctuated and eventually became similar to those of the sedimentary strata. By comprehensively considering the ores along with the geological characteristics of the deposit, we determined that deep magma provided the Au during ore formation. Later tectonic changes provided Sb from the sedimentary strata,which precipitated along fault expansion areas and produced Au and Sb paragenesis.

关键词： Au-Sb mineralization Arsenopyrite Pyrite Stibnite Metallogenetic process

Intake of tobacco nitrosamines of smokers in various provinces of China and their cancer risk:A meta-analysis

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2024年第7期141卷 249-260页

作者： Xiao Li Zhiwei Ye jun Wang Pengfei Lin Xiaojin Zhang Shuguang xie Chao Chen Research Institute for Environmental Innovation(Suzhou) TsinghuaSuzhouJiangsu 215163China State Key Joint Laboratory of Environmental simulation and Pollution Control School of EnvironmentTsinghua UniversityBeijing 100084China Shenzhen Key Laboratory of Organic Pollution Prevention and Control State Key Laboratory of Urban Water Resource and EnvironmentHarbin Institute of TechnologyShenzhen 518055China State Key Joint Laboratory of Environmental simulation and Pollution Control College of Environmental Science and EngineeringPeking UniversityBeijing 100871China

Nitrosamines are a class of carcinogens which have been detected widely in food,water,some pharmaceuticals as well as tobacco.The objectives of this paper include reviewing the basic information on tobacco consumption and nitrosamine contents,and assessing the health risks of tobacco nitrosamines exposure to Chinese smokers.We searched the publications in English from“Web of Science”and those in Chinese from the“China National Knowledge Infrastructure”in 2022 and collected 151 literatures with valid information.The content of main nitrosamines in tobacco,including 4-(methylnitrosoamino)-1-(3-pyridyl)-1-butanone(NNK),N-nitrosonornicotine(NNN),N-nitrosoanatabine(NAT),N-nitrosoanabasine(NAB),total tobacco-specific nitrosamines(TSNA),and N-nitrosodimethylamine(NDMA)were summarized.The information of daily tobacco consumption of smokers in 30 provinces of China was also collected.Then,the intakes of NNN,NNK,NAT,NAB,TSNAs,and NDMA via tobacco smoke were estimated as 1534ng/day,591 ng/day,685 ng/day,81 ng/day,2543 ng/day,and 484 ng/day by adult smokers in30 provinces,respectively.The cancer risk(CR)values for NNN and NNK inhalation intake were further calculated as 1.44×10^(-5)and 1.95×10^(-4).The CR value for NDMA intake via tobacco smoke(inhalation:1.66×10^(-4))indicates that NDMA is similarly dangerous in tobacco smoke when compared with the TSNAs.In China,the CR values caused by average nitrosamines intake via various exposures and their order can be estimated as the following:smoke(3.75×10^(-4))>food(1.74×10^(-4))>drinking water(1.38×10^(-5)).Smokers in China averagely suffer 200%of extra cancer risk caused by nitrosamines in tobacco when compared with non-smokers.

关键词： N-nitrosamine Tobacco Cancer risk Tobacco specific nitrosamines(TSNAs) N-nitrosodimethylamine(NDMA)