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Copper coordination-driven self-assembly and encapsulation of PCR reagents

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Chinese Chemical Letters 2024年第3期35卷 189-192页

作者： Chang Lu Jinkai Zheng juewen liu Institute of Food Science and Technology Chinese Academy of Agricultural SciencesBeijing 100193China Department of Chemistry Waterloo Institute for NanotechnologyUniversity of WaterlooWaterlooONN2L 3G1Canada

Polymerase chain reactions(PCR)are a very important tool for use in cloning,nucleic acid sequencing and diagnostic testing.The storage conditions of PCR reagents are limited to freezing and a lot of mixing steps are needed.In this paper,we report using metal ions to form coordination nanomaterials with the intrinsic components of the PCR reagents including dNTP,DNA primers and DNA polymerase as an integrated PCR reaction system.To complete PCR reactions,users need only to dissolve the coordination nanomaterials with a buffer and add template DNA.A few transition metal ions were screened and Cu^(2+)was found to be the most effective metal ion for this purpose.Then the encapsulation efficiency of PCR reagents was measured,which can reach close to 100%for the primers and DNA polymerase,but only 10%for dNTP because dNTP was excess.Further study also exhibited this integrated PCR reaction system can be used for DNA detection with a similar detection limit to the normal PCR,and showed good stability of encapsulated PCR nanomaterial after storage for a week.

关键词： Metal ions Coordination Encapsulation PCR Storage

Fabrication and Properties of a New Reactive Diluent for Cationic UV Curing

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Journal of Wuhan University of Technology(Materials Science) 2024年第4期39卷 1053-1060页

作者：吴正森黄笔武 liu Yuansheng SHEN Han School of Physics and Materials Science Nanchang UniversityNanchang 330031China

The reactive diluent prepared by siloxane modified Trimethylene oxide can improve the performance of the UV curing system.Therefore,1,7-bis[(3-ethyl-3-methoxyoxacylobutane)propyl]octadecylosiloxane(BEMOPOMTS)was synthesized from diethyl carbonate,trimethylopropanes,allyl bromide,and 1,1,3,3,5,5,7,7-octadecylosiloxane as the main raw materials.BEMOPOMTS can be used as reactive diluents in the field of cationic UV curing.It has good thermal stability,and the addition of BEMOPOMTS significantly improves the tensile strength and elongation at break of epoxy resin.Compared with the pure epoxy resin,adding 20%BEMOPOMTS increased the elastic modulus by 25%to 677 MPa.

关键词： UV curing cation curing reactive diluent siloxane

Underestimated benefits of NO_(x) control in reducing SNA and O_(3) based on missing heterogeneous HONO sources

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Frontiers of Environmental Science & Engineering 2024年第3期18卷 57-67页

作者： Shuping Zhang Haotian Zheng Jun liu Yao Shi Tianzeng Chen Chaoyang Xue Fenfen Zhang Yueqi Jiang Xiangping Zhang Shovan Kumar Sahu biwu Chu Jia Xing State Key Joint Laboratory of Environment Simulation and Pollution Control School of EnvironmentTsinghua UniversityBeijing 100084China China Academy of Civil Aviation Science and Technology Beijing 100028China State Key Joint Laboratory of Environment Simulation and Pollution Control Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China Yellow River Institute of Hydraulic Research Zhengzhou 450003China Centre for Climate Research Singapore Meteorological Service SingaporeSingapore 537054Singapore

Substantial NO_(x) emission mitigation is crucial for the synergistic reduction of particulate matter and ozone(O_(3))pollution in China.The traditional air quality model does not consider heterogeneous HONO chemistry,leading to uncertainties in estimating the benefits of NO_(x) control.Previous studies have shown that the parameterization of heterogeneous HONO formation increases both the simulated value of sulfate–nitrate–ammonium(SNA)and that of O_(3),thus adding the heterogeneous reactions of HONO into air quality models inevitably leads to changes in the estimated benefits of NO_(x) abatement.Here we investigated the changes in SNA and O_(3)concentrations from NO_(x) emission reduction before and after adding heterogeneous HONO reactions in the Community Multi-Scale Air Quality(CMAQ)model.Including heterogeneous HONO reactions in the simulation improved the benefits of NO_(x) reduction in terms of SNA control in winter.With 80%NO_(x) reduction,the reduction in SNA increased from 36.9%without considering heterogeneous HONO reactions to 42.8%with heterogeneous HONO chemistry.The reduction in the maximum daily 8h average(MDA8)O_(3)in summer caused by NO_(x) reduction increased slightly from 4.7%to 5.2%after adding heterogeneous HONO reactions.The results in this study highlight the enhanced effectiveness of NO_(x) controls for the reduction of SNA and O_(3)after considering heterogeneous HONO formation in a complex chemical ambient,demonstrating the importance of NO_(x) controls in reducing PM2.5 and O_(3)pollution in China.

关键词： Heterogeneous HONO NO_(x) reduction PM_(2.5) O_(3)

激光熔化沉积Al-Mg-Sc-Zr合金单熔道成形质量预测

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中国有色金属学报 2024年第4期34卷 1010-1021页

作者：肖罡李伟奇谢莉路超刘筱朱必武杨钦文湖南科技大学机电工程学院湘潭411201 江西铜业技术研究院有限公司南昌330096 湖南大学机械与运载工程学院长沙410082 广东海洋大学材料科学与工程学院阳江529559

本研究探讨了激光熔化沉积(LMD)工艺参数对Al-Mg-Sc-Zr合金单熔道成形质量的影响,并采用BP神经网络模型和改进的PSO-BP神经网络模型预测了不同工艺参数下的成形孔隙率。结果表明:Al-Mg-Sc-Zr合金的LMD单熔道成形孔隙率,随着激光线能量... 详细信息

本研究探讨了激光熔化沉积(LMD)工艺参数对Al-Mg-Sc-Zr合金单熔道成形质量的影响,并采用BP神经网络模型和改进的PSO-BP神经网络模型预测了不同工艺参数下的成形孔隙率。结果表明:Al-Mg-Sc-Zr合金的LMD单熔道成形孔隙率,随着激光线能量密度的增加呈现先上升后下降再上升的趋势,在175 J/mm^(2)时孔隙率达到最小值,仅为1.38%。在相同的送粉工艺参数下,LMD成形熔道宽度和熔道深度均与激光功率呈现出正相关性,而熔道高度和熔道深度均与扫描速率呈现出负相关性。相较于BP神经网络模型,改进的PSO-BP神经网络模型的平均绝对误差降低了29.69%,平均相对误差降低了19.42%,均方误差降低了19.02%,相关系数提升了63.44%。

关键词：激光熔化沉积 Al-Mg-Sc-Zr合金熔池质量孔隙率神经网络

中高应变速率轧制AZ31镁合金板的抗拉强度预测

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中国有色金属学报 2024年第6期34卷 1998-2007页

作者：朱必武蒋昊刘筱郭鹏程魏福安徐从昌李落星湖南科技大学机电工程学院高功效轻合金构件成形技术及耐损伤性能评价湖南省工程研究中心湘潭411201 青海大学部省合建盐湖化工大型系列研究设施西宁810016 湖南大学重庆研究院重庆401135 集美大学海洋装备与机械工程学院厦门361021

本文采集了不同轧制温度、应变速率以及压下量等三个工艺参数下中高应变速率轧制的AZ31镁合金抗拉强度的27组样本,通过惯性权重、学习因子的改进和引入变异操作对PSO-BP神经网络进行改进,并与BP、PSO-BP神经网络对比,进行抗拉强度的预... 详细信息

本文采集了不同轧制温度、应变速率以及压下量等三个工艺参数下中高应变速率轧制的AZ31镁合金抗拉强度的27组样本,通过惯性权重、学习因子的改进和引入变异操作对PSO-BP神经网络进行改进,并与BP、PSO-BP神经网络对比,进行抗拉强度的预测。结果表明:BP神经网络不能预测AZ31镁合金抗拉强度的非线性变化,PSO-BP神经网络和改进的PSO-BP(IPSO-BP)神经网络均能较好地预测AZ31镁合金抗拉强度的非线性变化;这三个模型中IPSO-BP神经网络预测最为准确,相较于PSO-BP神经网络,其平均绝对误差从15.3764降低至3.4288,平均相对误差从5.94%降低至1.32%,均方误差从251.3662降低至20.7199,相关系数从0.7753提高至0.8937;通过Pearson相关性计算判断出应变速率、压下量对抗拉强度的影响均大于轧制温度,而应变速率与抗拉强度呈负相关关系,压下量与抗拉强度呈正相关关系。

关键词： AZ31镁合金神经网络轧制工艺抗拉强度 Pearson相关系数

Nucleobase,nucleoside,nucleotide,and oligonucleotide coordinated metal ions for sensing and biomedicine applications

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Nano Research 2022年第1期15卷 71-84页

作者： Jiaojiao Zhou Heyou Han juewen liu State Key Laboratory of Agricultural Microbiology College of Food Science and TechnologyHuazhong Agricultural UniversityWuhan 430070China Department of Chemistry Waterloo Institute for NanotechnologyUniversity of WaterlooWaterlooON N2L 3G1Canada

Metal ions play critical roles in chemical,biological,and environmental processes.Various biomolecules have the ability to coordinate with metal ions and form various materials.Nucleobases,nucleosides,and nucleotides,as the essential components of DNA,have emerged as a useful building block for the construction of functional nanomaterials.In recent years,DNA oligonucleotides have also been used for this purpose.We herein review the strategies for the synthesis of soft nanomaterials through the assembly of nucleotides(or DNA)and metal ions to yield various nanoparticles,fibers,and hydrogels.Such coordination methods are simple to operate and can be carried out under ambient conditions.The luminescent,catalytic,and molecular recognition properties of these coordination materials are described with representative recent examples.Their applications ranging from biosensing,enzyme encapsulation,catalysis,templated shell growth to cancer therapy are highlighted.Finally,challenges of this field and future perspectives are discussed.

关键词： nucleotides DNA metal ions self-assembly nanostructures

The microstructure evolution and deformation mechanism in a casting AM80 magnesium alloy under ultra-high strain rate loading

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Journal of Magnesium and Alloys 2022年第11期10卷 3205-3216页

作者： Pengcheng Guo Xiao liu biwu Zhu Wenhui liu Liqiang Zhang School of Mechanical and Electrical Engineering Central South University of Forestry and TechnologyChangsha 410004China School of Material Science and Engineering Hunan University of Science and TechnologyXiangtanHunan 411201China

Ultra-high strain rate impact tests were conducted by Split-Hopkinson pressure bar to investigate the microstructure evolution and impact deformation mechanism of a solution treated casting AM80 Mg alloy at 25, 150 and 250 ℃ with a strain rate of 5000 s^(-1). The microcrack and dynamic recrystallization(DRX) preferentially nucleate at grain boundary(GB) and twin boundary(TB), especially at the intersections between GBs and TBs, and then propagate along twin direction. In contrast, the adiabatic shear bands preferentially occur at high-density twined regions. At 25 ℃, the dominated deformation mechanisms are basal slip and twinning. As deformation temperature increases to 150and 250℃, the deformation gradually shifts to be dominated by a coordinated mechanism among non-basal slip, twinning and DRX. The flow stress behavior and deformation mechanism indicate that the degree of decrease in flow stress with temperature is associated with the change of deformation mode.

关键词： AM80 mg alloy Deformation mechanism Ultra-high strain rate Twinning Dynamic recrystallization

Signaling Kinetics of DNA and Aptamer Biosensors Revealing Graphene Oxide Surface Heterogeneity

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Journal of Analysis and Testing 2022年第1期6卷 11-18页

作者： Po-Jung Jimmy Huang juewen liu Department of Chemistry Waterloo Institute for NanotechnologyUniversity of WaterlooWaterlooON N2L 3G1Canada

Adsorption of fluorescently labeled DNA and aptamer probes to graphene oxide(GO)has been one of the most popular methods for developing biosensors.In the presence of target analytes,the quenched fluorescence would recover.In this work,we followed the kinetics of the reactions and found that the fluorescence would eventually drop after an initial increase,and this was attributed to the re-adsorption of the desorbed probe DNA molecules.Both a DNA probe and an aptamer for adenosine were used.This re-adsorption was attributed to the surface heterogeneity of GO,and the DNA probes desorbed from relatively weaker binding sites were re-adsorbed on the stronger binding sites.This re-adsorption can be avoided by extensive washing the samples,and also by blocking the GO surface or by heating.This fundamental understanding is important for achieving a stable signal of such biosensors.

关键词： Kinetics DNA Aptamer Biosensors Graphene

Unveiling the mechanical response and accommodation mechanism of pre-rolled AZ31 magnesium alloy under high-speed impact loading

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Journal of Magnesium and Alloys 2022年第4期10卷 1096-1108页

作者： Xiao liu Hui Yang biwu Zhu Yuanzhi Wu Wenhui liu Changping Tang Key Laboratory of High Temperature Wear Resistant Materials Preparation Technology of Hunan Province Hunan University of Science and TechnologyXiangtanHunan 411201China Research Institute of Automobile Parts Technology Hunan Institute of TechnologyHengyangHunan 421002China

Split Hopkinson pressure bar(SHPB)tests were conducted on pre-rolled AZ31 magnesium alloy at 150–350℃ with strain rates of 2150s-1,3430s^(-1) and 4160s-1.The mechanical response,microstructural evolution and accommodation mechanism of the pre-rolled AZ31 magnesium alloy under high-speed impact loading were investigated.The twin and shear band are prevailing at low temperature,and the coexistence of twins and recrystallized grains is the dominant microstructure at medium temperature,while at high temperature,dynamic recrystallization(DRX)is almost complete.The increment of temperature reduces the critical condition difference between twinning and DRX,and the recrystallized temperature decreases with increasing strain rate.The mechanical response is related to the competition among the shear band strengthen,the twin strengthen and the fine grain strengthen and determined by the prevailing grain structure.The fine grain strengthen could compensate soften caused by the temperature increase and the reduction of twin and shear band.During high-speed deformation,different twin variants,introduced by pre-rolling,induce different deformation mechanism to accommodate plastic deformation and are in favor for non-basal slip.At low temperature,the high-speed deformation is achieved by twinning,dislocation slip and the following deformation shear band at different deformation stages.At high temperature,the high-speed deformation is realized by twinning and dislocation slip of early deformation stage,transition shear band of medium deformation stage and DRX of final deformation stage.

关键词： Mechanical response Pre-twinning Accommodation mechanism Pre-rolled AZ31 magnesium alloy High-speed impact loading