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Efficient hiv-1 in vitro reverse transcription: optimal capsid stability is required

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Signal Transduction and Targeted Therapy 2021年第2期6卷 195-196页

作者： Ryan C.Burdick Vinay K.Pathak Viral Mutation Section HIV Dynamics and Replication ProgramCenter for Cancer ResearchNational Cancer Institute at FrederickFrederickMD 21702USA

Recently,Christensen et *** hiv-1 reverse transcription and integration in a cell-free system and found that viral double-stranded DNA that is capable of integration into a target plasmid DNA was efficiently synthesized within viral cores,indicating that the capsid protein shell plays an important role in viral genome replication.1 hiv-1 reverse transcriptase(RT)copies the viral genomic RNA into a double-stranded DNA,and hiv-1 integrase(IN)inserts the viral DNA into the host genome to form a *** RT and IN have been successfully targeted with potent antiretroviral drugs to inhibit these enzymes and treat patients infected with hiv-1,the causative agent of acquired immunodeficiency syndrome(AIDS).Despite decades of research,the molecular mechanisms of reverse transcription and integration in vivo are not fully characterized,in part because cell-free assays that efficiently and faithfully recapitulate the processes in the context of a virion have not been available。

关键词： al. drugs optimal

Acoustoelectric effect in semiconductor materials and devices

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Chinese Journal of Acoustics 1990年第3期9卷 275-279页

作者： V.R.SINGH Awadhesh PRASAD national Physical laboratory New delhi-110012lindiaNational Physical LaboratoryNew delhi-110012lindia

This paper reviews the studies on acoustoelectric effect in extrinsic semiconductor materials used in various scientific and other measurements. A historical review of earlier findings is given with special reference to associated mechanisms. Acoustoelectric studies in solid state devioes require further attention and the work done in this area is also discussed.

关键词： Acoustoelectric effect in semiconductor materials and devices

Eff ect of polystyrene microplastics and temperature on growth,intestinal histology and immune responses of brine shrimp Artemia franciscana

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Journal of Oceanology and Limnology 2021年第3期39卷 979-988页

作者： Xuekai HAN Yuyu ZHENG Chaoling DAI Hu DUAN Meirong GAO Md Rayhan ALI Liying SUI Asian Regional Artemia reference Center Tianjin Key Laboratory of Marine Resources and ChemistryCollege of Marine and Environmental SciencesTianjin University of Science and TechnologyTianjin 300457China

Microplastics pollution and seawater temperature rise have been the major environmental issues,threatening the survival and biodiversity of marine *** study evaluated the combined effect of temperature and polystyrene microplastics(MP)on Artemia,a filter-feeding crustacean that is widely used for environmental toxicology *** shrimp Artemia franciscana were exposed to three MP concentrations(0,0.2,and 2.0 mg/L)and three temperatures(22,26,and 30℃)for 14 *** general,higher MP concentration and temperature led to a decreased survival rate and ***-way ANOVA analysis indicated that the survival rate of Artemia was significantly impacted by both MP concentration and temperature(P0.05).Growth of Artemia was significantly impacted by temperature(P<0.05),and with a significant interaction between two factors(P<0.05).Furthermore,the enzymatic activity,intestinal histological analyses,and immune gene expression were determined for Artemia reared at 30℃ with three MP concentrations(0,0.2,and 2.0 mg/L).The results showed that 2.0-mg/L MP resulted in reduced Artemia intestinal microvilli and exfoliated epithelia cells,significantly increased acid phosphatase(ACP)activity(P<0.05)and immunerelated gene ADRA1 B and CREB3 expression,revealing that higher MP concentration could induce oxidative and immunological stress on Artemia at 30℃.Overall,our study suggests that MP and temperature have combined adverse effect on Artemia,especially at relatively high temperature and polystyrene MP *** findings are important to understand the potential ecological risks posed by these two factors on the organisms in marine environment.

关键词： Artemia franciscana combined effect microplastics temperature

A Novel Design and Fabrication of Magnetic Random Access Memory Based on Nano-ring-type Magnetic Tunnel Junctions

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Journal of Materials Science & Technology 2007年第3期23卷 304-306页

作者： X.F.Han H.X.Wei Z.L.Peng H.D.Yang J.F.Feng G.X.Du Z.B.Sun L.X.Jiang Q.H.Qin M.Ma Y.Wang Z.C.Wen D.P.Liu W.S.Zhan State Key laboratory of Magnetism Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Science Beijing 100080 China

Nano-ring-type magnetic tunnel junctions （NR-MTJs） with the layer structure of Ta（5）/Ir22Mn78（10）/ Co75Fe25（2）/Ru（0.75）/CoooFe20B20（3）/Al（0.6）-oxide/Co60Fe20B20（2.5）/Ta（3）/Ru（5）（thickness unit： nm） were nano-fabricated on the Si（100）/SiO2 substrate using magnetron sputtering deposition combined with the optical lithography, electron beam lithography （EBL） and Ar ion-beam etching techniques. The smaller NR-MTJs with the inner- and outer-diameter of around 50 and 100 nm and also their corresponding NR-MTJ arrays were nano-patterned. The tunnelling magnetoresistance （TMR ＆ R） versus driving current （I） loops for a spin-polarized current switching were measured, and the TMR ratio of around 35% at room temperature were observed. The critical values of switching current for the free Co60Fe20B20 layer relative to the reference Co6oFe2oB2o layer between parallel and anti-parallel magnetization states were between 0.50 and 0.75 mA in such NR-MTJs. It is suggested that the applicable MRAM fabrication with the density and capacity higher than 256 Mbit/inch2 even 6 Gbite/inch2 are possible using both I NR-MTJ＋1 transistor structure and current switching mechanism based on based on our fabricated 4×4 MRAM demo devices.

关键词： Nano-ring-type magnetic tunnel junctions NR-MTJ MRAM spin polarization Spin transfer effect

Study on Echo Time-Delay Estimation of Pulsed Laser Fuze

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Journal of Beijing Institute of Technology 2010年第3期19卷 264-267页

作者：郭华玲邓甲昊桑会平蔡克荣 national Key laboratory for Mechatronics Engineering and Control Beijing Institute of Technology national Key laboratory for Electronic Measurement Technology North University of China

Pulse laser range detector is to measure the distance by estimating the time delay between the emitting pulse and echo *** this paper,a mathematical model for the target echo signal of laser fuze has been established;in accordance with this model,the formulas for echo time-delay estimation and for amplitude estimation based on least squares criterion have been *** is argued and simulated that the resolution of echo time-delay estimation could be improved through multi-reference correlation *** illustrate that the approach enables pulsed laser fuze to perform high-precision ranging under a low signal-to-noise ratio condition.

关键词： laser ranging technology echo time-delay estimation least squares criterion multi-reference correlation

Vacuum Ultraviolet Spectral Investigations on Green-Emitting Ca(La,Gd)_4Si_3O_(13):Tb^(3+) Phosphors for PDP Applications

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Journal of Rare Earths 2006年第z2期24卷 179-182页

作者：吴佳蓁陈炳铭陈登铭 Phosphors Research laboratory Department of Applied ChemistryNational Chiao Tung University Union Chemical laboratory Industrial Technology Research InstituteHsinchu 300TaiwanChina national Synchrotron Radiation Research Center

In an effort to develop new green-emitting PDP phosphors with high efficiency, investigated were the synthesis, VUV photoluminescence (PL) spectra, optical properties, and chromaticity of Ca(La1-x-yTbxGdy. )4Si3O13 phosphors by using synchrotron radiation. Upon analysis of the VUV spectroscopic and chromaticity investigations on the new greenemitting VUV phosphors, were an optimized composition achieved. The PLE spectral studies show that Ca ( La1-x-y TbxGdy)4Si3O13 exhibit significant absorption in the VUV range. The VUV PL intensity was found to enhance with Gd3+-doping. Furthermore, the 1931 CIE chromaticity coordinates of Ca(La,Gd)4Si3O13:Tb were found to be (0.286, 0.548), as compared to (0.230, 0.712) for Zn2SiP4:Mn2+ as a reference. The potential application of Ca(La,Gd)4Si3O13:Tb as a new green-emitting PDP phosphor are being currently improving and evaluating.

关键词： phosphors VUV spectra CIE chromaticity coordinates PDP

Rare earth upconversion nanophosphors: synthesis, functionalization and application as biolabels and energy transfer donors

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Journal of Rare Earths 2010年第6期28卷 807-819页

作者：张超孙聆东张亚文严纯华 Beijing national laboratory for Molecular Sciences State Key Laboratory of Rare Earth Materials Chemistry and Applications PKU-HKU Joint Laboratory on Rare Earth Materials and Bioinorganic Chemistry Peking University

This review focused on rare earth upconversion nanophosphors (UCNPs), a particular class of emitters whose photoluminescence mechanism is of fundamental difference from that of conventional dyes and semiconductor quantum dots. We in the first section gave a brief summary on a variety of synthetic methodologies developed during the past decades. Instead of presenting an exhaustive reference list, we selected only a few representative examples, illustrating the merits and limits of each involved synthetic route. Then we surveyed the recent progress in the functionalization techniques for these nanomaterials, depicting the modification in microstructures and improvement in properties with respect to the parent nanoparticles. And finally, we emphasized their application in the research fields of biolabeling and energy transfer, narrating their superior performance benefiting from the unique excitation and emission properties.

关键词： upconversien nanophosphor biolabel energy transfer rare earths

Occurring Mechanism and Restraining Method Research of Numerical Noise Signal in Penetration Simulation

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Chinese Journal of Mechanical Engineering 2016年第5期29卷 1037-1043页

作者： WANG Chen WANG Yabin national Key laboratory on Electromechanical Dynamic Control Beijing Institute of Technology Beijing 100081 China

In hard target penetration simulation, the existing researches of the convergence of results are mainly concentrating in the corresponding relationship between penetration depth and mesh scales. However, the influence of the mesh difference on the penetration resistance and acceleration signals are seldom refer to. This paper presents the occurring mechanism and restraining method of numerical noise signal in penetration simulation. First, the concept of the noise signal izs proposed. By taking a 3D penetration simulation as example, the influence of the noise signal on the penetration resistance in different mesh scales and impact velocity is studied. To ensure the convergence of the computational results, the grid scale of the target is encrypted to 1：1：8. In addition, modem spectrum analysis method is introduced to further analyze the penetration resistance signal. The research results presented is useful to improve the computational accuracy of high speed projectile penetration simulation, and provide important reference for carrying out structural design and optimization of fuze system.

关键词： hard target penetration numerical simulation signal of numerical noise spectral analysis

Molecular characterization of the rpoB gene mutations of Mycobacterium tuberculosis isolated from China

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Journal of Tuberculosis Research 2013年第1期1卷 1-8页

作者： Shengfen Wang Bing Zhao Yuanyuan Song Yang Zhou Yu Pang Xichao Ou Qiang Li Hui Xia Yanlin Zhao national Tuberculosis reference laboratory National Center for Tuberculosis Control and Prevention Chinese Center for Disease Control and Prevention Beijing China

Objective: To analyze characterization of the rpoBgene mutations of Mycobacterium tuber- culosis isolated from China and to explore the association of specific mutations conferring rifampicin (RIF) resistance with Beijing genotype strains. Methods: Genotypic analysis of 3479M. tuberculosis isolatesincluding 402 RIF-resistantand 3077 RIF-susceptible isolated from the na- tional drug-resistant tuberculosis baseline survey was performed. Results: DNA sequencing analysis of the 81-bp RIF resistance determining region (RRDR) of the ropB gene revealed that 98.01% of RIF-resistant strains showedrpoBgene mutation, isolates with mutations at codon rpoB531, rpoB 526 and rpoB 516 were the most frequently. Analysis of the rpoB gene of 3077 RIF-susceptible strains revealed that 98.96% of the strains had no mutation. The distribution of mutation frequency at differentcritical codons in different regions of China was statistically significant (p = 0.001). There was no significant difference in the occurrence of mutations at critical codons between the rifampicin-resistant Bei-jing and non-Beijing ***: About 98% of RIF-resistant strains isolated from China carry mutations in RRDR ofrpoB *** profiles in RIF-resistantM. tuberculosis clinical isolates are variable depending on the different geographical regionsof China. The results provide valuable information in adopting new molecular methods for diagnosis of TB in China.

关键词： Rifampicin Resistance Beijing Genotype