检索结果-南通市图书馆

Graphene-calcium carbonate coating to improve the degradation resistance and mechanical integrity of a biodegradable implant

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

journal of Magnesium and Alloys 2024年第1期12卷 394-404页

作者： Lokesh Choudhary Parama Chakraborty Banerjee R.K.Singh Raman derrek e.Lobo Christopher d.easton Mainak Majumder Frank Witte jörg F.Löffler department of Mechanical and Aerospace engineering Monash UniversityClayton CampusMelbourneVIC 3800Australia department of Chemical and Biological engineering Monash UniversityClayton CampusMelbourneVIC 3800Australia Nanoscale Science and engineering Laboratory(NSeL) Bldg 37Monash UniversityClayton CampusMelbourneVIC 3800Australia CSIRO Materials Science and engineering Bayview AvenueClaytonVIC 3168Australia julius Wolff Institute and Berlin Brandenburg Center for Regenerative Therapies Charité–Universitätsmedizin BerlinAugustenburger Platz 113353 BerlinGermany Laboratory of Metal Physics and Technology Department of MaterialsETH Zurich8093 ZurichSwitzerland

Biodegradable implants are critical for regenerative orthopaedic procedures,but they may suffer from too fast corrosion in human-body *** necessitates the synthesis of a suitable coating that may improve the corrosion resistance of these implants without compromising their mechanical *** this study,an AZ91 magnesium alloy,as a representative for a biodegradable mg implant material,was modified with a thin reduced graphene oxide(RGO)-calcium carbonate(CaCO_(3))composite *** analytical and in-vitro electrochemical characterization reveals that this coating significantly improves the corrosion resistance and mechanical integrity,and thus has the potential to greatly extend the related application field.

关键词： Graphene coating Biodegradable implant Hydroxyapatite Corrosion Magnesium alloy

The effects of local variations in conditions on carbon storage and release in the continental mantle

在线全文

学校读者我要写书评

暂无评论

National Science Review 2024年第06期 22-36页

作者： Stephen F.Foley Chunfei Chen dorrit e.jacob School of Natural Sciences Macquarie University Research School of earth Sciences Australian National University State Key Laboratory of Geological Processes and Mineral Resources School of Earth Sciences China University of Geosciences

Recent advances indicate that the amount of carbon released by gradual degassing from the mantle needs to be revised upwards, whereas the carbon supplied by plumes may have been overestimated in the *** in rock types and oxidation state may be very local and exert strong influences on carbon storage and release mechanisms. deep subduction may be prevented by diapirism in thick sedimentary packages,whereas carbonates in thinner sequences may be subducted. Carbonates stored in the mantle transition zone will melt when they heat up, recognized by coupled stable isotope systems(e.g. mg, Zn, Ca). There is no single ‘mantle oxygen fugacity’, particularly in the thermal boundary layer(TBL) and lowermost lithosphere, where very local mixtures of rock types coexist. Carbonate-rich melts from either subduction or melting of the uppermost asthenosphere trap carbon by redox freezing or as carbonate-rich dykes in this zone. deeply derived, reduced melts may form further diamond reservoirs, recognized as polycrystalline diamonds associated with websteritic silicate minerals. Carbon is released by either edge-driven convection,which tears sections of the TBL and lower lithosphere down so that they melt by a mixture of heating and oxidation, or by lateral advection of solids beneath rifts. Both mechanisms operate at steps in lithosphere thickness and result in carbonate-rich melts, explaining the spatial association of craton edges and carbonate-rich magmatism. High-pressure experiments on individual rock types, and increasingly on reactions between rocks and melts, are fine-tuning our understanding of processes and turning up unexpected results that are not seen in studies of single rocks. Future research should concentrate on elucidating local variations and integrating these with the interpretation of geophysical signals. Global concepts such as average sediment compositions and a uniform mantle oxidation state are not appropriate for small-scale processes; an increa

关键词：

Recent progress in fatigue behavior of mg alloys in air and aqueous media: A review

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

journal of Materials Science & Technology 2017年第10期33卷 1075-1086页

作者： B.j.Wang S.d.Wang d.K.Xu e.H.Han School of environmental and Chemical engineering Shenyang Ligong University CAS Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal Research Chinese Academy of Sciences

due to the interactions between mechanics and chemistry, mg alloys are inevitably subjected to the combined effect of corrosion attack and cyclic loading, which eventually leads to corrosion fatigue failure. In this paper, fundamental aspects regarding the fatigue behavior of mg alloys have been reviewed,including：（1） fatigue behavior of mg alloys in air and aqueous media; and（2） the influence of microstructure, anodic dissolution, hydrogen embrittlement（He）, heat treatment and surface protection on fatigue behavior of mg alloys. Moreover, some remaining unresolved issues and future targets to deeply understand the failure mechanism of corrosion fatigue have been described.

关键词： Magnesium alloys Fatigue Corrosion fatigue Crack initiation Hydrogen embrittlement

dietary supplementation of zinc oxide modulates intestinal functionality during the post-weaning period in clinically healthy piglets

在线全文

学校读者我要写书评

暂无评论

journal of Animal Science and Biotechnology 2024年第1期15卷 313-328页

作者： dirkjan Schokker Soumya K.Kar els Willems Alex Bossers Ruud A.dekker Alfons j.M.jansman Wageningen Bioveterinary Research LelystadThe Netherlands Wageningen Livestock Research Wageningen University&ResearchWageningenThe Netherlands Royal Agrifirm Group ApeldoornThe Netherlands Institute for Risk Assessment Sciences Utrecht UniversityUtrechtThe Netherlands

Background To improve our understanding of host and intestinal microbiome interaction,this research investigated the effects of a high-level zinc oxide in the diet as model intervention on the intestinal microbiome and small intestinal functionality in clinically healthy post-weaning *** study 1,piglets received either a high concentration of zinc(Zn)as zinc oxide(Zn O,Zn,2,690 mg/kg)or a low Zn concentration(100 mg/kg)in the diet during the post weaning period(d 14–23).The effects on the piglet's small intestinal microbiome and functionality of intestinal tissue were *** study 2,the impact of timing of the dietary zinc intervention was investigated,i.e.,between d 0–14 and/or d 14–23 post weaning,and the consecutive effects on the piglet's intestinal functionality,here referring to microbiota composition and diversity and gene expression *** differences in the small intestinal functionality were observed during the post weaning period between piglets receiving a diet with a low or high concentration Zn O content.A shift in the microbiota composition in the small intestine was observed that could be characterized as a non-pathological change,where mainly the commensals *** the immediate post weaning period,i.e.,d 0–14,the highest number of differentially expressed genes(deGs)in intestinal tissue were observed between animals receiving a diet with a low or high concentration Zn O content,i.e.,23 deGs in jejunal tissue and 11 deGs in ileal *** genes are involved in biological processes related to immunity and inflammatory *** example,genes Cd59 and ReG3G were downregulated in the animals receiving a diet with a high concentration Zn O content compared to low Zn O content in both jejunum and ileum *** the second study,a similar result was obtained regarding the expression of genes in intestinal tissue related to immune pathways when comparing piglets receiving a diet with a high concentration Zn O con

关键词： Immune system Intestinal functionality Microbiota Piglets Zinc oxide

Fatigue crack initiation of magnesium alloys under elastic stress amplitudes:A review

在线全文

学校读者我要写书评

暂无评论

Frontiers of Mechanical engineering 2019年第1期14卷 113-127页

作者： B.j.WANG d.K.XU S.d.WANG e.H.HAN School of environmental and Chemical engineering Shenyang Ligong UniversityShenyang 110159China CAS Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China

The most advantageous property of magnesium(mg)alloys is their density,which is lower compared with traditional metallic *** alloys,considered the lightest metallic structural material among others,have great potential for applications as secondary load components in the transportation and aerospace *** fatigue evaluation of mg alloys under elastic stress amplitudes is very important in ensuring their service safety and *** their hexagonal close packed structure,the fatigue crack initiation of mg and its alloys is closely related to the deformation mechanisms of twiuning and basal ***,for mg alloys with shrinkage porosities and inclusions,fatigue cracks will preferentially initiate at these defects,remarkably reducing the fatigue *** this paper,some fundamental aspects about the fatigue crack initiation mechanisms of mg alloys are reviewed,in cluding the 3 followings:1)Fatigue crack initiation of as-cast mg alloys,2)influence of microstructure on fatigue crack initiation of wrought mg alloys,and 3)the effect of heat treatment on fatigue initiation ***,some unresolved issues and future target on the fatigue crack initiation mechanism of mg alloys are also described.

关键词： mg alloys fatigue behavior microstructure crack initiation deformation mechanism

Modular next generation fast-neutron detector for portal monitoring

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

Nuclear Science and Techniques 2022年第1期33卷 140-148页

作者： e.Aboud S.Ahn G.V.Rogachev V.e.johnson j.Bishop G.Christian e.Koshchiy C.e.Parker d.P.Scriven Cyclotron Institute Texas A&M UniversityCollege StationTX 77843USA department of Physics and Astronomy Texas A&M UniversityCollege StationTX 77843USA department of Statistics Texas A&M UniversityCollege StationTX 77843USA

Nuclear nonproliferation is of critical importance for global *** fissile materials including highly enriched uranium and weapons-grade plutonium are especially important to *** interrogation techniques may result in much better sensitivity but are difficult with conventional portal monitors that rely on detecting thermal ***,most conventional portal monitoring systems rely on ^(3)He,which has a finite and continually decreasing *** designing a highly segmented array of organic scintillators,we posit that we can accurately and quickly identify fissile materials,including weapons-grade plutonium and highly enriched uranium,being *** propose a new design for a fast-neutron detector that overcomes the limitations of the current generation of portal ***6 simulations have been performed in conjunction with the UMPBT statistical model to determine the sensitivity limitations of the proposed *** suggest that the proposed detector may be 10 times more efficient than current-generation thermal neutron detectors and may be able to positively identify a 81 mg 235U source in as little as 192 seconds utilizing active interrogation techniques.

关键词： Fast-neutron detection Portal monitoring Nonproliferation

Oxygen tension modulates cell function in an in vitro three-dimensional glioblastoma tumor model

在线全文

学校读者我要写书评

暂无评论

Bio-design and Manufacturing 2024年第3期7卷 307-319页

作者： Sen Wang Siqi Yao Na Pei Luge Bai Zhiyan Hao dichen Li jiankang He j.Miguel Oliveira Xiaoyan Xue Ling Wang Xinggang Mao State Key Laboratory for Manufacturing System engineering Xi’an Jiaotong UniversityXi’an 710054China School of Mechanical engineering Xi’an Jiaotong UniversityXi’an 710054China NMPA Key Laboratory for Research and evaluation of Additive Manufacturing Medical devices Xi’an Jiaotong UniversityXi’an 710054China 3B’s Research Group I3Bs–Research Institute on BiomaterialsBiodegradables and BiomimeticsUniversity of MinhoHeadquarters of the European Institute of Excellence on Tissue Engineering and Regenerative MedicineAveParkZona Industrial da Gandra4805-017 BarcoGuimarãesPortugal ICVS/3B’s-PT Government Associate Laboratory 4806-909 Braga/Guimar˜aesPortugal department of Pharmacology School of PharmacyFourth Military Medical UniversityXi’an 710032China department of Neurosurgery Xijing HospitalFourth Military Medical UniversityXi’an 710032China

Hypoxia is a typical feature of the tumor microenvironment,one of the most critical factors affecting cell behavior and tumor ***,the lack of tumor models able to precisely emulate natural brain tumor tissue has impeded the study of the effects of hypoxia on the progression and growth of tumor *** study reports a three-dimensional(3d)brain tumor model obtained by encapsulating U87mg(U87)cells in a hydrogel containing type I *** also documents the effect of various oxygen concentrations(1%,7%,and 21%)in the culture environment on U87 cell morphology,proliferation,viability,cell cycle,apoptosis rate,and ***,it compares two-dimensional(2d)and 3d *** comparison purposes,cells cultured in flat culture dishes were used as the control(2d model).Cells cultured in the 3d model proliferated more slowly but had a higher apoptosis rate and proportion of cells in the resting phase(G0 phase)/gap I phase(G1 phase)than those cultured in the 2d ***,the two models yielded significantly different cell ***,hypoxia(e.g.,1%O2)affected cell morphology,slowed cell growth,reduced cell viability,and increased the apoptosis rate in the 3d *** results indicate that the constructed 3d model is effective for investigating the effects of biological and chemical factors on cell morphology and function,and can be more representative of the tumor microenvironment than 2d culture *** developed 3d glioblastoma tumor model is equally applicable to other studies in pharmacology and pathology.

关键词： Hypoxia Glioma Three-dimensional glioma model In vitro

Relationship between the fatigue behavior and grain structures of an as-extruded mg-6.2%Zn-0.6%Zr(in wt.%)alloy

在线全文

学校读者我要写书评

暂无评论

journal of Materials Science & Technology 2023年第18期149卷 119-126页

作者： B.j.Wang d.K.Xu C.L.jiang L.Y.Sheng e.H.Han School of environmental and Chemical engineering Shenyang Ligong UniversityShenyang 110159China Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Binzhou Institute of Technology Binzhou 256606China Shandong Key Laboratory of Advanced Aluminium Materials and Technology Binzhou 256606China Shenzhen Institute Shenzhen Key Lab Human Tissue Regenerate&RepairPeking UniversityShenzhen 518057China

Through investigating the tension-tension fatigue behavior of an as-extruded mg-6.2 wt.%Zn-0.6 wt.%Zr(ZK60)alloy,it revealed that the determined fatigue strength at 107 cycles was quite sensitive to the grain *** them,the fine grain structure had the highest fatigue strength of 130 MPa,whereas the typical“bi-modal”grain structure had the lowest fatigue strength of 110 *** analysis demon-strated that for the fine grain structure,fatigue cracks preferentially nucleated at grain *** the“bi-modal”and coarse grain structures,the fatigue crack initiation was dominated by the cracking along slip bands.

关键词： mg alloys Grain structure Cyclic slips Fatigue behavior Crack initiation

Linking leaf elemental traits to biomass across forest biomes in the Himalayas

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

Science China earth Sciences 2024年第5期67卷 1518-1528页

作者： Nita dYOLA eryuan LIANG josep PeÑUeLAS j.julio CAMAReRO Shalik Ram SIGdeL Sugam ARYAL Wentao LIN Xiang LIU Yongwen LIU Xingliang XU Sergio ROSSI State Key Laboratory of Tibetan Plateau earth System Environment and Resources(TPESER)Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China Laboratoire sur lesécosystèmes terrestres boréaux Département des Sciences FondamentalesUniversitédu QuébecàChicoutimi555Boulevard de l′UniversitéChicoutimi(QC)G7H2B1Canada CSIC Global Ecology Unit CREAF-CSIC-UABBellaterraE-08193 CataloniaSpain CReAF Cerdanyola del VallèsE-08193 CataloniaSpain Instituto Pirenaico de ecología(IPe-CSIC) Avenida Montañana 1005Zaragoza 50059Spain Friedrich-Alexander-Universität erlangen-Nürnberg Institut für GeographieErlangen 91058Germany State Key Laboratory of Grassland Agro-ecosystems College of EcologyLanzhou UniversityLanzhou 730000China Key Laboratory of ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China

Plants require a number of essential elements in different proportions for ensuring their growth and *** elemental concentrations in leaves reflect the functions and adaptations of plants under specific environmental ***,less is known about how the spectrum of leaf elements associated with resource acquisition,photosynthesis and growth regulates forest biomass along broad elevational *** examined the influence of leaf element distribution and diversity on forest biomass by analyzing ten elements(C,N,P,K,Ca,mg,Zn,Fe,Cu,and Mn)in tree communities situated every 100 meters along an extensive elevation gradient,ranging from the tropical forest(80 meters above sea level)to the alpine treeline(4200 meters above sea level)in the Kangchenjunga Landscape in eastern Nepal *** calculated communityweighted averages(reflecting dominant traits governing biomass,i.e.,mass-ratio effect)and functional divergence(reflecting increased trait variety,i.e.,complementarity effect)for leaf elements in a total of 1,859 trees representing 116 *** increasing mass-ratio effect and decreasing complementarity in leaf elements enhance forest biomass accumulation.A combination of elements together with elevation explains biomass(52.2%of the variance)better than individual elemental trait diversity(0.05%to 21%of the variance).elevation modulates trait diversity among plant species in biomass *** promotes biomass at lower elevations,but reduces biomass at higher elevations,demonstrating an interaction between elevation and *** interaction between elevation and mass-ratio effect produces heterogeneous effects on biomass along the elevation *** research indicates that biomass accumulation can be disproportionately affected by elevation due to interactions among trait diversities across vegetation *** higher trait variation enhances the adaptation of species to environmental changes,it reduces

关键词： ecosystem function elevational gradient Functional diversity Functional traits Leaf elements Niche complementarity