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A comparative study of magnetic properties between whole cells and isolated magnetosomes of Magnetospirillum magneticum AMB-1

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Chinese Science Bulletin 2010年第1期55卷 38-44页

作者： LI JinHua PAN YongXin LIU QingSong QIN HuaFeng DENG ChengLong CHE RenChao YANG XinAn Key laboratory of the Earth's Deep Interior Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China Graduate University of Chinese Academy of Sciences Beijing 100049 China Franco-Chinese Biomineralization and Nano-structures laboratory Beijing 100029 China State Key laboratory of Lithospheric Evolution Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China Beijing National laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100080 China

The magnetic properties of magnetosome magnetite are of interdisciplinary interest because magnetosomes are potential carriers of natural remanent magnetization and paleoenvironment, as well as novel nano-biomaterials in biotechnological and biomedical applications. We carried out magnetic and electron transmission microscopy analyses of fresh Magnetospirillum magneticum AMB-1 whole cells and isolated magnetosomes. Results revealed that AMB-1 synthesized single-domain magnetite magneto-somes, which are arranged in the form of linear fragmental chain. The distinct differences of magnetic properties between these two samples can be faithfully interpreted in terms of spatial arrangement of magnetosomes and magnetostatic interaction. For the whole cells, the strong intra-chain interactions and weak inter-chain interactions generate behaviors of non-interacting uniaxial single-domain particles. Its δ-ratio is 3.0 and passes the Moskowitz test. In contrast, the isolated magnetosome sample has reduced values of coercivity and δ-ratio (1.5), due to increasing three-dimensional magnetostatic interactions and collapse of magneto-some chains. These observations provide useful insights into applications of the biogenic magnetite (magnetosomes) in magnetic nano-materials and magnetofossils in the paleomagnetic and environmental magnetism.

关键词：磁悬浮细胞磁特性弱相互作用生物医学应用纳米生物技术磁性纳米材料生物材料

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Sterilization mechanism of helium/helium-oxygen atmospheric-pressure pulsed dielectric barrier discharge on membrane surface

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Plasma Science and Technology 2022年第12期24卷 173-181页

作者： Xingyu CHEN Yuhan Li Mengqi LI Zilan XIONG State Key laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and TechnologyWuhan 430074People's Republic of China

Pulsed dielectric barrier discharge(PDBD) exhibits several applications in different fields;however,the interaction of its components with substances remains a key *** this study,we employed experimental and numerical modeling to investigate the interactions between different PDBD components and substances in pure helium and a helium-oxygen mixture.A membrane comprising a Staphylococcus aureus strain was utilized as the treatment object to demonstrate the trace actions of the evolutions and distributions of certain components on the surface of the *** results revealed that the shapes and sizes of the discharging area and inhibition zone differed between *** a pure helium condition,a discharge layer existed along the membrane surface,lying beside the main discharging channel within the electrode ***,an annulus inhibition zone was formed at the outer edge of the electrode in the pure helium group at 30 s and 1 min,and this zone extended to a solid circle at 2 min with a radius that was~50% larger than that of the electrode ***,the discharging channel and inhibition zone in the helium-oxygen mixture were constrained inside the electrode area without forming any annulus.A 2D symmetrical model was developed with COMSOL to simulate the spatiotemporal distributions of different particles over the membrane surface,and the result demonstrated that the main components,which formed the annulus inhibition zone under the pure helium condition,contributed to the high concentration of the He^(+)annulus that was formed at the outer edge of the ***,O^(+)and O_(2)^(+)were the main components that killed the bacteria under the helium-oxygen mixture *** results reveal that the homogenization treatment on a material surface via PDBD is closely related to the treatment time and working gas.

关键词： pulsed dielectric barrier discharge interaction mechanism numerical modeling spatiotemporal distribution of species treatment substance

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PHASE BEHAVIOR OF CHARGE STABLIZED COLLOID DISPERSION WITH ADDED WATER SOLUBLE POLYMERS

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Chinese Journal of Polymer Science 2013年第9期31卷 1218-1224页

作者： Jia-xue Liu Yong-feng Men State Key laboratory of Polymer Physics and Chemistry Changchun Institute of Applied Chemistry Chinese Academy of Sciences University of Chinese Academy of Sciences

Demixing and colloidal crystallization in the mixture of charge stabilized colloidal poly（methyl methacrylate） particles and soluble poly（ethylene oxide） were investigated by means of synchrotron small-angle X-ray scattering （SAXS） technique. Phase diagram of the mixture was obtained based on visual inspection and SAXS results. The phase behavior is determined as a function of the concentration of the polymer as well as the volume fraction of the colloidal particles. The system shows a one phase region when the concentration of the polymer is low, whereas a two-phase region is present when the concentration of the polymer is larger than a critical concentration at certain volume fraction of the colloids. Interestingly, a face centered cubic colloidal crystalline structure was formed under certain conditions, which has been rarely observed in experiments of colloid-polymer mixtures with competing interactions.

关键词： Colloid-polymer mixture Phase behavior Crystallization.

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Opinion: hazards faced by macromolecules when confined to thin aqueous films

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Biophysics Reports 2017年第Z1期3卷 1-7页

作者： Robert M.Glaeser Bong-Gyoon Han Lawrence Berkeley National laboratory University of California

Samples prepared for single-particle electron cryo-microscopy(cryo-EM) necessarily have a very high surface-to-volume ratio during the short period of time between thinning and vitrification. During thi time, there is an obvious risk that macromolecules of interest may adsorb to the air–water interface with a preferred orientation, or that they may even become partially or fully unfolded at the interface In addition, adsorption of macromolecules to an air–water interface may occur even before thinning This paper addresses the question whether currently used methods of sample preparation might be improved if one could avoid such interfacial interactions. One possible way to do so might be to preemptively form a surfactant monolayer over the air–water interfaces, to serve as a structure-friendly slide and coverslip. An alternative is to immobilize particles of interest by binding them to some type o support film, which—to continue using the analogy—thus serves as a slide. In this case, the goal is no only to prevent the particles of interest from diffusing into contact with the air–water interface but also to increase the number of particles seen in each image. In this direction, it is natural to think o developing various types of affinity grids as structure-friendly alternatives to thin carbon films. Perhap ironically, if precautions are not taken against adsorption of particles to air–water interfaces, sacrificia monolayers of denatured protein may take the roles of slide, coverslip, or even both.

关键词： Sample preparation Cryo-EM Air–water interface Protein denaturation

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Comparison of optical properties of bioaerosols composed of microbial spores and hyphae[Invited]

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Chinese Optics Letters 2023年第9期21卷 40-46页

作者：王新宇胡以华杨星顾有林何海浩丁婉莹王鹏 Electronic Countermeasure Institute National University of Defense TechnologyHefei 230037China State Key laboratory of Pulsed Power Laser Technology National University of Defense TechnologyHefei 230037China Advanced Laser Technology laboratory of Anhui Province Hefei 230037China Key laboratory of High Magnetic Field and Ion Beam Physical biology Hefei Institute of Physical ScienceChinese Academy of SciencesHefei 230037China

Bioaerosols exhibit significant broadband extinction performance and have vital impacts on climate change,optical detection,communication,disease transmission,and the development of optical attenuation *** spores and microbial hyphae represent two primary forms of bioaerosol ***,a comprehensive investigation and comparison of their optical properties have not been conducted *** this paper,the spectra of spores and hyphae were tested,and the absorption peaks,component contents,and protein structural differences were *** structural models were established,and the optical attenuation parameters were *** chamber experiments were conducted to verify the optical attenuation performance of microbial spores and hyphae in the mid-infrared and far-infrared spectral *** demonstrate that selecting spores and hyphae can significantly reduce the average transmittance from 21.2%to 6.4%in the mid-infrared band and from 31.3%to 19.6%in the far-infrared band within three *** conclusions have significant implications for the selection of high-performance microbial optical attenuation materials as well as for the rapid detection of bioaerosol types in research on climate change and the spread of pathogenic aerosols.

关键词： bioaerosol optical properties optical materials light-matter interactions Fourier transform infrared spectra.

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Monodisperse amino-modified nanosized zero-valent iron for selective and recyclable removal of TNT: Synthesis, characterization, and removal mechanism

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Journal of Environmental Sciences 2021年第5期33卷 69-79页

作者： Jing Li Qingxiang Zhou Miao Li Yongli Liu Qinan Song School of Environment Tsinghua UniversityBeijing 100084China State Key laboratory of Heavy Oil Processing State Key Laboratory of Petroleum Pollution ControlCollege of Chemical Engineering and EnvironmentChina University of Petroleum BeijingBeijing 102249China School of Environment Henan Normal UniversityXinxiangHenan 453007China

Nitroaromatic explosives are major pollutants produced during wars that cause serious environmental and health problems. The removal of a typical nitroaromatic explosive, 2,4,6-trinitrotoluene(TNT), from aqueous solution, was conducted using a new recyclable magnetic nano-adsorbent(Fe@SiO_(2) –NH_(2)). This adsorbent was prepared by grafting amino groups onto Fe@SiO_(2) particles with a well-defined core-shell structure and demonstrated monodispersity in solution. The removal performance of the nano-adsorbent towards TNT was found to be 2.57 and 4.92 times higher than that towards two analogous explosives, 2,4-dinitrotoluene(2,4-DNT) and 2-nitrotoluene(2-NT), respectively, under neutral conditions. The difference in the removal performance among the three compounds was further compared in terms of the effects of different conditions(pH value, ionic strength, humic acid concentration, adsorbent modification degree and dosage, etc.) and the electrostatic potential distributions of the three compounds. The most significant elevation is owing to modification of amino on Fe@SiO_(2) which made a 20.7% increase in adsorption efficiency of TNT. The experimental data were well fit by the pseudo-second-order kinetic model and the Freundlich adsorption isotherm model, indicating multilayer adsorption on a heterogeneous surface. The experimental results and theoretical considerations show that the interactions between Fe@SiO_(2) –NH_(2) NPs and TNT correspond to dipole-dipole and hydrophobic interactions. These interactions should be considered in the design of an adsorbent. Furthermore, the adaptability to aqueous environment and excellent regeneration capacity of Fe@SiO_(2) –NH_(2) NPs makes these remediation materials promising for applications.

关键词： Nanosized zero-valent iron particles(NZVIs) 2 4 6-trinitrotoluene(TNT) Removal Mechanism Regeneration

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Investigation of mutual effects among additives in electrolyte for plasma electrolytic oxidation on magnesium alloys

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Journal of Magnesium and Alloys 2020年第2期8卷 523-536页

作者： Lingyun An Ying Ma Le Sun Zhanying Wang Sheng Wang State Key laboratory of Advanced Processing and Recycling of Non-ferrous Metals Lanzhou University of TechnologyLanzhou 730050China

Plasma electrolytic oxidation(PEO)coatings were prepared on AZ91D magnesium alloys in alkaline silicate-based electrolyte with and without *** mutual effects among additives including TiC particles,dispersant polyethylene glycol 6000(PEG6000)and anionic surfactant sodium dodecyl sulfate(SDS)were studied based on orthogonal *** content and distribution of TiC deposited in the coatings were measured by EPMA and *** thicknesses,phase compositions,microstructures and corrosion resistances of the codlings were cAarnined by using TT260 eddy current tuickncss gage,XRD,SEM and clcctrochcniical test,*** results show that the experiment design of this study is the key to study the mutual effects among these *** additive and their interactions all remarkably influence TiC content and corrosion resistance of the *** size TiC is much easier to migrate towards the anode,and the interaction between PEG6000 and SDS both effectively prevents its agglomeration and increases the number of its negative surface charges,which further increase the migration rate and the deposited uniformity of TiC and make TiC have more opportunity to deposit in the discharge ***,when smaller size TiC,PEG6000 and SDS are all added into the electrolyte,they could improve the anti-corrosion property of the coating to the largest extent attributed to higher TiC content and the densest microstructure of the coating.

关键词： Magnesium alloys Plasma electrolytic oxidation Additives Mutual effects Orthogonal experiment Corrosion resistance

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Preparation and Characterization of Monodisperse Nickel Nanoparticles by Polyol Process

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Journal of Wuhan University of Technology(Materials Science) 2005年第4期20卷 35-37页

作者：李鹏 State Key laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070 China

Polymer-protected monodisperse nickel nanoparticles were synthesized by a modified polyol reduction method in the presence of poly（N-vinyl-2-Pyrrolidone）.These nanoparticles were characterized by transmission electron microscopy（TEM）,X-ray diffraction（XRD）,selected area electron diffraction（SAED）,as well as vibrating sample magnetometer（VSM）.The experimental results show that the addition of PVP and the concentration of NaOh have strong influences on the *** and uniformity of *** the presence of PVP and NaoH with low *** nickel nanoparticles with average diameters about 42 nm were obtained and characterized to the pure nickel crystalline with foc *** structures such as *** strings resulted from magnetic interactions between particles were *** chemical interaction between the PVP and nickel nanoparticles was found by *** saturation magnetization（Ms）.remanent magnetization（Mr）and coercivity（Hc）of these nickel nanoparticles are lower than those of bulk nickel.

关键词： nickel magnetic nanparticles polyol process PVP

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Fe_(3)O_(4)@silica nanoparticles for reliable identification and magnetic separation of Listeria monocytogenes based on molecular-scale physiochemical interactions

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Journal of Materials Science & Technology 2021年第25期84卷 116-123页

作者： Huawei Rong Tong Gao Yun Zheng Lingwei Li Dake Xu Xuefeng Zhang Yanglong Hou Mi Yan Key laboratory for Anisotropy and Texture of Materials(MOE) School of Materials Science and EngineeringNortheastern UniversityShenyang 110819China Key laboratory of Electromagnetic Processing of Materials(Ministry of Education) School of Materials Science and EngineeringNortheastern UniversityShenyang 110819China Institute of Advanced Magnetic Materials College of Materials and Environmental EngineeringHangzhou Dianzi UniversityHangzhou 310012China Beijing Key laboratory for Magnetoelectric Materials and Device(BKLMMD) Beijing Innovation Center for Engineering Science and Advanced Technology(BIC-ESAT)Department of Materials Science and EngineeringCollege of EngineeringPeking UniversityBeijing 100871China State Key laboratory of Silicon Materials School of Materials Science and EngineeringZhejiang UniversityHangzhou 310027China

Listeria monocytogenes(***)is one of the top five dangerous foodborne pathogens which widely exists in most raw food and has approximately 30%mortality rate in high-risk *** safety caused by foodborne pathogens is still a major problem faced by humans in all *** conventional analytical methods currently used involve complex bacteriological tests and usually take several days for incubation and ***,in order to prevent the spread of disease,the development of a detection method with high speed,high accuracy and sensitivity is urgent and ***,we developed an approach for the identification and magnetic capture of *** by using core@shell Fe_(3)O_(4)@silica nanoparticles terminated with hydroxyl or amine *** results show that both amine-and hydroxyl-terminated Fe_(3)O_(4)@silica core@shell nanoparticles functionalized with specific antibodies,present 95.2%±6.2%and 98.6%±0.3%capture efficacies,***,without conjugating the specific antibodies,the hydroxyl-terminated Fe_(3)O_(4)@silica nanoparticles exhibit 17.6%±1.6%efficacy,while the amine-terminated one remains 93.2%±9.2%capture efficiency ascribed to the high *** study quantitatively uncovers the specific and non-specific recognitions relevant to the molecular-scale physiochemical interactions between the microorganisms and the functionalized particles,and the results from this work can be generalized and extended to other bacterial species by changing antibodies,also have important implications in developing advanced analytic methods.

关键词： Listeria monocytogenes Magnetic capture Fe_(3)O_(4)@silica Functionalized nanoparticles

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Dual-filler reinforced PVDF-HFP based polymer electrolyte enabling high-safety design of lithium metal batteries

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Nano Research 2024年第6期17卷 5251-5260页

作者： Chang Fang Kangsheng Huang Jing Zhao Shiqi Tian Hui Dou Xiaogang Zhang Jiangsu Key laboratory of Electrochemical Energy Storage Technologies College of Materials Science and TechnologyNanjing University of Aeronautics and AstronauticsNanjing 210016China

Despite the high energy density of lithium metal batteries(LMBs),their application in rechargeable batteries is still hampered due to insufficient ***,we present a novel flame-retardant solid-state electrolyte based on polyvinylidene fluoride-hexafluoropropylene(PVDF-HFP)with nano SiO_(2)aerogel as an inert filler but Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)(LLZTO)as an auxiliary component to enhance the ion *** introduction of SiO_(2)aerogels imparts the polymer electrolyte with exceptional thermal stability and flame ***,the interaction between hydroxyl groups of SiO_(2)particles and PVDF-HFP creates a strong cross-linking structure,enhancing the mechanical strength and stability of the ***,the presence of SiO_(2)aerogel and LLZTO facilitates the dissociation of lithium salts through Lewis acid-base interactions,resulting in a high ionic conductivity of 1.01×10^(−3)S·cm^(−1)and a wide electrochemical window of~5.0 V at room temperature for the prepared ***,the assembled Li|Li cell demonstrates the excellent resistance to lithium dendrite and runs stablly for over 1500 h at a current density of 0.25 mA·cm^(−2).Thus,we prepare a pouch cell with high safety,which can work normally after short-circuiting under the external folding and cutting.

关键词： polymer electrolyte SiO_(2)/Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)(LLZTO)dual-filler non-flammable long cycle life lithium metal battery

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