检索结果-南通市图书馆

A CELL-CENTERED GOduNOV METHOD BASED ON STAGGERED DATA DISTRIBUTION,PART Ⅰ:ONE-DIMENSIONAL CASE

在线全文

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2024年第4期42卷 1172-1196页

作者： jiayin Zhai Xiao Li Zhijun Shen Institute of Applied Physics and Computational Mathematics LCPP.O.Box 8009-26Beijing 100088China College of Big Data and Internet Shenzhen Technology UniversityShenzhen 518118China Center for Applied Physics and Technology HEDPSPeking UniversityChina

This paper presents a cell-centered Godunov method based on staggered data distribu-tion in Eulerian *** motivation is to reduce the intrinsic entropy dissipation of classical Godunov methods in the calculation of an isentropic or rarefaction *** the same time,the property of accurate shock capturing is also *** analyzing the factors that cause nonphysical entropy in the conventional Godunov methods,we introduce two velocities rather than a single velocity in a cell to reduce kinetic energy dissipation.A series of redistribution strategies are adopted to update subcell quantities in order to improve *** examples validate that the present method can dramatically reduce nonphysical entropy *** subject classification:35Q35,76N15,76M12.

关键词： Godunov method Riemann solver Rarefaction wave Nonphysical entropy increase.

Blending with transition metals improves bioresorbable zinc as better medical implants

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

Bioactive Materials 2023年第2期20卷 243-258页

作者： Yingchao Su jiayin Fu Juncen Zhou Elias Georgas Shaokang du Yi-Xian Qin Yadong Wang Yufeng Zheng Donghui Zhu Department of Biomedical Engineering Stony Brook UniversityStony BrookNYUSA Nancy E.and Peter C.Meinig School of Biomedical Engineering Cornell UniversityIthacaNYUSA Department of Cardiology Sir Run Run Shaw HospitalZhejiang UniversityHangzhouZhejiangChina Academy for Advanced Interdisciplinary Studies Peking UniversityBeijingChina School of Materials Science and Engineering Peking UniversityBeijingChina

Zinc(Zn)is a new class of bioresorbable metal that has potential for cardiovascular stent material,orthopedic implants,wound closure devices,***,pure Zn is not ideal for these applications due to its low mechanical strength and localized degradation *** is the most common/effective way to overcome this ***,the choice of alloying element is crucial to ensure the resulting alloy possesses sufficient mechanical strength,suitable degradation rate,and acceptable ***,we proposed to blend selective transition metals(i.e.,vanadium-V,chromium-Cr,and zirconium-Zr)to improve Zn’s *** selected transition metals have similar properties to Zn and thus are beneficial for the metallurgy process and mechanical ***,the biosafety of these elements is of less concern as they all have been used as regulatory approved medical implants or a component of an implant such as Ti6Al4V,CoCr,or Zr-based dental *** study showed the first evidence that blending with transition metals V,Cr,or Zr can improve Zn’s properties as bioresorbable medical *** addition,three in vivo implantation models were explored in rats:subcutaneous,aorta,and femoral implantations,to target the potential clinical applications of bioresorbable Zn implants.

关键词： Degradation Cardiovascular Orthopedic Subcutaneous Antibacterial

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

人工智能伦理漂洗现象及其治理

自然辩证法通讯 2025年第1期47卷 9-17页

作者：杨进杜严勇同济大学人文学院

人工智能伦理漂洗现象在现实中的频发引起了学界和公众的重视。从概念上而言，作为一种行动的伦理漂洗呈现出两种要素特征：动机上的虚伪性与结果上的虚假性。就其成因而言，伦理漂洗的形成受到动机因素(生产者的利益追求与消费者和管... 详细信息

人工智能伦理漂洗现象在现实中的频发引起了学界和公众的重视。从概念上而言，作为一种行动的伦理漂洗呈现出两种要素特征：动机上的虚伪性与结果上的虚假性。就其成因而言，伦理漂洗的形成受到动机因素(生产者的利益追求与消费者和管理者的安全-权益需求)与外部因素(人工智能伦理的有效性，人工智能对伦理的冲击，信息差与治理成本差)的综合性决定。由于伦理漂洗在实践与心理层面都造成了负面的伦理影响，对它的治理需要从内(道德心理)与外(现实制度)两个层面展开。

关键词：人工智能伦理伦理漂洗伦理治理

Internet of things intrusion detection model and algorithm based on cloud computing and multi-feature extraction extreme learning machine

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Digital Communications and Networks 2023年第1期9卷 111-124页

作者： Haifeng Lin Qilin Xue jiayin Feng Di Bai Nanjing Forestry University China Nanjing Agricultural University China Hebei Normal University of Science and Technology China

With the rapid development of the Internet of Things(IoT),there are several challenges pertaining to security in IoT *** with the characteristics of the traditional Internet,the IoT has many problems,such as large assets,complex and diverse structures,and lack of computing *** network intrusion detection systems cannot meet the security needs of IoT *** view of this situation,this study applies cloud computing and machine learning to the intrusion detection system of IoT to improve detection ***,traditional intrusion detection algorithms require considerable time for training,and these intrusion detection algorithms are not suitable for cloud computing due to the limited computing power and storage capacity of cloud nodes;therefore,it is necessary to study intrusion detection algorithms with low weights,short training time,and high detection accuracy for deployment and application on cloud *** appropriate classification algorithm is a primary factor for deploying cloud computing intrusion prevention systems and a prerequisite for the system to respond to intrusion and reduce intrusion *** paper discusses the problems related to IoT intrusion prevention in cloud computing *** on the analysis of cloud computing security threats,this study extensively explores IoT intrusion detection,cloud node monitoring,and intrusion response in cloud computing environments by using cloud computing,an improved extreme learning machine,and other *** use the Multi-Feature Extraction Extreme Learning Machine(MFE-ELM)algorithm for cloud computing,which adds a multi-feature extraction process to cloud servers,and use the deployed MFE-ELM algorithm on cloud nodes to detect and discover network intrusions to cloud *** our simulation experiments,a classical dataset for intrusion detection is selected as a test,and test steps such as data preprocessing,feature engineering,model training,an

关键词： Internet of Things Cloud Computing Intrusion Prevention Intrusion Detection Extreme Learning Machine

Mesoporous Bioglass/Silk Fibroin Scaffolds as a Drug Delivery System: Fabrication, Drug Loading and Release in vitro and Repair Calvarial Defects in vivo

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(Materials Science) 2014年第2期29卷 401-406页

作者：张晓欣 ZHANG jiayin 施斌 Hospital of Stomatology Wuhan University

The potential of combining bioactive glass（MBG） and silk fibroin（SF） together as a new drug delivery system was evaluated. The three-dimensional porous scaffolds were selected as the form of SF, and sol-gel method was adopted to fabricate MBG in this study. The characteristic of the synthesized material was measured by transmission electron microscopy and scanning electron microscopy. In vitro evaluation of drug delivery was carried out in terms of drug loading and drug release. And aspirin was chosen as the drug for scaffolds to carry out in vitro tests and repair BALB/C mice calvarial defects. Bone formation was examined by microcomputed tomography. The experimental results show that MBG/silk scaffolds have better physiochemical properties compared with silk scaffolds. In comparison to pure silk scaffolds, MBG/silk scaffolds enhance the drug loading efficiency, release rate in vitro and promote bone regeneration in vivo. Thus we conclude that MBG/silk scaffold is a more efficient drug delivery system than pure silk scaffolds.

关键词： silk fibroin mesoporous bioactive glass drug delivery calvarial defect aspirin

Complicated target recognition by archaeal box C/D guide RNAs

在线全文

学校读者我要写书评

暂无评论

Science China(Life Sciences) 2024年第4期67卷 631-644页

作者： jiayin Wang Songlin Wu Keqiong Ye Key Laboratory of RNA Science and Engineering CAS Center for Excellence in BiomacromoleculesInstitute of BiophysicsChinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China

Box C/D RNAs guide the site-specific formation of 2′-O-methylated nucleotides(Nm)of RNAs in eukaryotes and *** C/D RNAs have been profiled in several archaea,their targets have not been experimentally ***,we mapped Nm in r RNAs,t RNAs,and abundant small RNAs(s RNAs)and profiled C/D RNAs in the crenarchaeon Sulfolobus *** targets of C/D RNAs were assigned by analysis of base-pairing interactions,in vitro modification assays,and gene deletion experiments,revealing a complicated landscape of C/D RNA-target interactions.C/D RNAs widely use dual antisense elements to target adjacent sites in r RNAs,enhancing modification at weakly bound *** consecutive sites can be guided with the same antisense element upstream of box D or D′,a phenomenon known as doublespecificity that is exclusive to internal box D′in eukaryotic C/D *** C/D RNAs guide modification at a single non-canonical *** study reveals the global landscape of RNA-guided 2′-O-methylation in an archaeon and unexpected targeting rules employed by C/D RNA.

关键词： C/D RNA 2′-O-methylation archaea guide RNA RNA modification

Improved mechanical, degradation, and biological performances of Zn–Fe alloys as bioresorbable implants

在线全文

学校读者我要写书评

暂无评论

Bioactive Materials 2022年第11期7卷 334-343页

作者： Yingchao Su jiayin Fu Wonsae Lee Shaokang du Yi-Xian Qin Yufeng Zheng Yadong Wang Donghui Zhu Department of Biomedical Engineering Stony Brook UniversityStony BrookNYUSA Nancy E.and Peter C.Meinig School of Biomedical Engineering Cornell UniversityIthacaNYUSA Department of Cardiology Sir Run Run Shaw HospitalZhejiang UniversityHangzhouZhejiangChina Academy for Advanced Interdisciplinary Studies Peking UniversityBeijingChina School of Materials Science and Engineering Peking UniversityBeijingChina

Zinc(Zn)is a promising bioresorbable implant material with more moderate degradation rate compared to magnesium(Mg)and iron(Fe).However,the low mechanical strength and localized degradation behavior of pure Zn limit its clinical *** is one of the most effective ways to overcome these *** screening the alloying element candidates regarding their potentials for improvement on the degradation and biocompatibility,we proposed Fe as the alloying element for Zn,and investigated the in vitro and in vivo performances of these alloys in both subcutaneous and femoral *** showed that the uniformly distributed secondary phase in Zn–Fe alloys significantly improved the mechanical property and facilitated uniform degradation,which thus enhanced their biocompatibility,especially the Zn-0.4Fe ***,these Zn–Fe alloys showed outstanding antibacterial *** together,Zn–Fe alloys could be promising can-didates as bioresorbable medical implants for various cardiovascular,wound closure,and orthopedic applications.

关键词： Zinc Mechanical Degradation Biocompatibility Antibacterial

Inhibition effects of perfluoroalkyl acids on progesterone production in mLTC-1

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

Journal of Environmental Sciences 2017年第6期29卷 272-280页

作者： Wei Zhao Ruina Cui Jianshe Wang jiayin Dai Key Laboratory of Animal Ecology and Conservation Biology Institute of ZoologyChinese Academy of SciencesBeijing 100101China

Perfluoroalkyl substances （PFASs） are a class of fluorine substituted carboxylic acid, sulfonic acid and alcohol, structurally similar to their corresponding parent compounds. Previous study demonstrated the potential endocrine disruption and reproductive toxicity of perfluorooctane sulfonic acid and perfluorooctanoic acid, two dominant PFASs in animals and humans. We explored the relationship between eleven perfluoroalkyl acids （PFAAs） with different carbon chain length and their ability to inhibit progesterone production in mouse Leydig tumor cells （mLTC-1）. We found an obvious dose-response relationship between progesterone inhibition rate and PFAA exposure concentration in mLTC-1. The relative inhibition rate of progesterone by PFAAs was linearly related to the carbon chain length and molar refractivity of PFAAs. Mitochondrial membrane potential （MMP） decreased after PFAA exposure at the half-maximal inhibitory effect concentration （IC50） of progesterone production in mLTC-1, while the reactive oxygen species （ROS） content increased significantly. These results imply that the inhibition effect of PFAAs on progesterone production might be due, in part, to ROS damage and the decrease in MMP in mLTC-1.

关键词： Perfluoroalkyl substancesProgesteroneMitochondrial membrane potentialReactive oxygen species

Toxic effects of perfluorononanoic acid on the development of Zebrafish(Danio rerio) embryos

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2015年第6期27卷 26-34页

作者： Hui Liu Nan Sheng Wei Zhang jiayin Dai Key Laboratory of Animal Ecology and Conservation Biology Institute of Zoology Chinese Academy of Sciences University of Chinese Academy of Sciences

Perfluorononanoic acid（PFNA） is a nine-carbon perfluoroalkyl acid widely used in industrial and domestic products. It is a persistent organic pollutant found in the environment as well as in the tissues of humans and wildlife. There is a concern that this chemical might be a developmental toxicant and teratogen in various ecosystems. In the present study,the toxic effects of PFNA were evaluated in zebrafish（Danio rerio） embryos. One hour post-fertilization embryos were treated with 0, 25, 50, 100, 200, 300, 350, and 400 μmol/L PFNA for 96 hr in 6-well plates. Developmental phenotypes and hatching rates were observed and recorded. Nineteen genes related to oxidative stress and lipid metabolism were examined using Quantitative RT-PCR and confirmed by whole mount in situ hybridization（WISH）. Results showed that PFNA delayed the development of zebrafish embryos, reduced the hatching rate, and caused ventricular edema and malformation of the spine. In addition, the amount of reactive oxygen species in the embryo bodies increased significantly after exposure to PFNA compared with that of the control group. The Quantitative RT-PCR and WISH experiments demonstrated that m RNA expression of the lfabp and ucp2 genes increased significantly while that of sod1 and mt-nd1 decreased significantly after PFNA exposure. The m RNA expression levels of gpx1 and mt-atp6 decreased significantly in the high concentration group. However, the m RNA expression levels of both ppara and pparg did not show any significant variation after exposure. These findings suggest that PFNA affected the development of zebrafish embryos at relatively low concentrations.

关键词： Perfluorononanoic acid Zebrafish embryo Danio rerio Developmental toxicity