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hVEGF165 Expression in Escherichia coli Conserves Its Biological Function

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Journal of Chemistry and Chemical Engineering 2012年第8期6卷 738-743页

作者： Gabajova Blanka Valkova Danka Bohac Andrej Kovacova Elena Moravcik Roman zeman michal Department of Organic Chemistry FNS Comenius University Bratislava 84215 Slovak Republic Department of Animal Physiology and Ethology FNS Comenius University Bratislava 84215 Slovak Republic

The paper describes the expression of human protein VEGF165 in Escherichia coli and its purification. This growth factor isoform contains exon 7, which is essential for binding to extracellular domain of VEGF receptor 2, located on endothelial cells lining the surface of blood vessels. This binding stimulates the cascade of downstream signalling events leading to process known as angiogenesis, hVEGF165 overexpressed with His-tag in BL21 E. coli cells forms inclusion bodies （insoluble protein）, so the research found the procedure for its solubilization and purification on a Nickel based affinity chromatography. Although this eukaryotic signal protein needs posttranslational processing for its full function as a homodimer, author verified the biological activity of our hVEGF165 protein, obtained as monomer, by wound healing test.

关键词： VEGFI65 endothelial cells hypoxia angiogenesis inclusion bodies protein purification wound healing test.

Polymeric hollow fiber membrane for cooling crystallization seeding:On the mechanism of induced nucleation based on thermal transfer Author links open overlay panel

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Particuology 2024年第8期91卷 38-49页

作者： zeman He Shaofu Du Guanying Shao Peiyu Li Lei Sheng Gaohong He Xiaobin Jiang Wu Xiao State Key Laboratory of Fine Chemicals School of Chemical EngineeringEngineering Laboratory for Petrochemical Energy-efficient Separation Technology of Liaoning ProvinceDalian University of TechnologyDalian 116024China

Cooling crystallization is an important separation process and particuology technology that requires accurate nucleation control ***,we introduced the polymeric hollow fiber membrane with proper thermal properties as the effective nucleation induction interface during cooling *** heterogeneous nucleation control mechanism was introduced based on classical nucleation theory and the thermal transfer *** properties and the thermal conductivity of two kinds of polymeric membranes,polytetrafluoroethylene(PTFE)and polyethersulfone(PES),were measured and simulated with the developed *** two membranes possessed different nucleation induction periods,nucleation rates and crystallization performances,which validated that the hollow fiber membrane module could effectively accelerate the nucleation process compared to conventional cooling crystallization owing to the shorter nucleation induction period and the reduced solution surface *** to the higher hydrophobicity and the lower roughness of the membrane surface,the PTFE membrane possessed a more moderate performance in generating stable heterogeneous nucleation than the one of PES ***,the adjustable membrane property enabled the hollow fiber membrane-assisted cooling crystallization to possess the accurate nucleation control and desired terminal particle products.

关键词： Cooling crystallization Nucleation Particle process Hollow fiber membrane Induction period Process control

A new look on the electric spark sensitivity of nitramines

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Defence Technology（防务技术） 2020年第1期16卷 10-17页

作者： Svatopluk zeman Ning Liu Institute of Energetic Materials Faculty of Chemical TechnologyUniversity of PardubiceCZ-43210 PardubiceCzech Republic Xi'an Modern Chemistry Research Institute Xi'anShaanxi710065China

Electric spark energy,E_(ES),for a 50%probability of initiation of the 14 nitramines was determined using a measuring instrument in which the electrodes are in direct contact with the *** proportional relationships were established between the logarithm of the E_(ES)values and the length of the longest N-N bond in the nitramine *** finding is compatible with the mechanism of the first step in the electro-reduction of the nitramine *** proportional relationships were found to exist between the E_(ES)values and the crystal lattice free volumes,ΔV(*** increase in theΔV values increases the nitramine's resistance to electric sparks)but there were several nitramines with the opposite course of this *** a semilogarithic relationships between the E_(ES)values and a ratio of intrinsic volumes of molecule,V_(int),to theΔV values were described as well as ambiguous linear dependence between these energies and a sum of the positive and negative extremes of the molecular surface electrostatic potentials,V_(S,∑).Several nitramines studied(always the same ones)display roughly the same distribution in the coordinate systems of relationships with lengths of the longest N-N bonds,the Vint/ΔV ratio and the sum V_(S,∑)as the independent *** was found that,typically,such relationships start from a single identical point,in effect a point corresponding to data for a structural unit from which tho studied nitramines can be hypothetically generated,and/or are converging on another point,often the one corresponding to the data for *** the findings point to a fundamental influence of the intermolecular forces on reactivity of nitramines exposed to electric sparks.

关键词： Electric spark Free volume Initiation Nitramines Sensitivity

Impact Sensitivity in Respect of the Crystal Lattice Free Volume and the Characteristics of Plasticity of Some Nitramine Explosives

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含能材料 2015年第12期23卷 1186-1191页

作者： Svatopluk zeman Marcela JUNGOV Qi-Long YAN Institute of Energetic Materials Faculty of Chemical TechnologyUniversity of Pardubice

The relationship between the crystal lattice free volume,ΔV,and impact sensitivity,E_(dr),of ten nitramines has been analyzed. It was found that this relationship is not uniquely determined,i. e. it is not given only by their own ΔV values but fundamentally by the type and intensity of the intermolecular forces in the nitramine crystals. Also,relationships between the E_(dr)values,on the one hand,and bulk modulus,K,and shear modulus,G,on the other,have been the subject of discussion not only for pure cyclic nitramines but also for their PBXs,bonded by a poly-fluoro binder. The closest linear correlation exists between the E_(dr)values and dimensionless K·G^(-1) ratio which indicates the plasticity range. A similar relationship is valid also for the ΔV values. Relationships of the E_(dr) and / or ΔV values with the shear modulus or to the K·G^(-1) ratio reflect an unusual behavior of ε-HNIW to which the published morphological instability of this particular HNIW version might also be related.

关键词：爆破器料含能材料烟火器材材料学

Crystal lattice free volume and thermal decomposition of nitramines

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Defence Technology（防务技术） 2019年第1期15卷 51-57页

作者： Svatopluk zeman Ning Liu Ahmed K.Hussein Institute of Energetic Materials Faculty of Chemical TechnologyUniversity of Pardubice Xi’an Modern Chemistry Research Institute

The linear, directly proportional, equations between the Arrhenius parameters(E_α, and log A) of the thermal decomposition and the crystal lattice free space per molecule, △V, of 22 nitramines are described. It is shown that, because of a significant limitation by the molecular structural characteristics of such compounds, they are divided into a number of partial relationships. These partial relationships divide the nitramines into a group of substances relating to dimethyl nitramine and a sub-group related to e-HNIW. These directly proportional equations mean that an increase in the △Vvalues is related to an increase in the thermal stability of the corresponding nitramines. A comparison with similar published dependencies for the impact and friction sensitivities, on the one hand, and with the relationship between the E_a values and the sum of the negative and positive extremes of molecular surface electrostatic potentials, on the other, confirms the well-known fact that intermolecular interaction in the nitramines studied plays a decisive role in the thermal reactivity of such compounds. The crystal lattice free space manifests itself here perhaps only in the solid state thermal decomposition of RDX, HMX and DINGU. This study again confirms a level of disorder in the distribution of the forces in the crystal lattice of the"common" quality of e-HNIW,compared with its "reduced sensitivity(RS)" or pure analogues.

关键词： Crystal lattice Thermal decomposition Initiation reactivity Nitramines

The role of crystal lattice free volume in nitramine detonation

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Defence Technology（防务技术） 2019年第4期15卷 519-525页

作者： Svatopluk zeman Ning Liu Ahmed K. Hussein Institute of Energetic Materials Faculty of Chemical Technology University of Pardubice CZ-532 10 Pardubice Czech Republic Xi'an Modern Chemistry Research Institute Xi'an Shaanxi 710065 China Military Technical College Kobry Elkobbah Cairo Egypt

Crystal lattice free volumes,△V,of 22 nitramines introduced into relationships of maximal theoretical crystal densities(TMD),detonation velocities(D)and volume heats of explosives(ρ.Q).Values of all these characteristics increase with an increase in the AV ***,more realistic dependencies for the TMD and D values are obtained by using correlations with ratio of the intrinsic molecular volume,Vint,to△V(***/△V),whereby the dependence on the D values reflects their similar relationship to a sum of the positive(VS,max)and negative(VS,min)extremes of the molecular surface electrostatic potentials(VS,∑).Also,directly proportional linear relationships are specified between the VS,∑ values on the one hand,and the △V and Vint/△V values,on the *** is stated that the crystal lattice free volumes might have a similar role in detonation of nitramines as the intermolecular force effect in their molecular crystals(they are as if representative of such forces).

关键词： Crystal lattice Detonation Initiation reactivity Nitramines

Comparison with Molecular Surface Electrostatic Potential and Thermal Reactivity of Nitramines

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含能材料 2015年第12期23卷 1155-1161页

作者： Svatopluk zeman Zdenek Friedl Monika Bartoskova Qi-Long YAN Institute of Energetic Materials Faculty of Chemical TechnologyUniversityo f PardubiceCZ-53210PardubicetheCzechRepublic Facultyof Chemistry Brno Universityof TechnologyCZ.-61200Brnothe Czech Republic

Molecular surface electrostatic potentials V_S(r) ( ESP) of seventeen nitramines have been calculated. As a criterion of the imbalance between the maximum positive,V_(S,max) and minimum negative,V_(S,min),values of molecular surface electrostatic potentials their sum was derived and used as a new simple characteristic for ESPs-V_(S,Σ). These V_(S,Σ) values have close relationships with the Arrhenius parameters,activation energy E_a and preexponent log A,of thermal decomposition of the nitramines studied. The correlation between the V_(S,Σ) values and heats of fusion of the nitramines studied is described. These findings suggested analyzing the physico-chemical behavior of the nitramine crystals during this decomposition; in this connection an investigation was carried out using isothermal thermogravimetry and scanning electron microscopy of thermally exposed crystals of cis-1,3,4,6-tetranitrooctahydroimidazo-[4,5-d]imidazole( sintering of its crystal surfaces),of β-1,3,5,7-tetranitro-1,3,5,7-tetrazocane( cracking of its crystals during β !δ transition) and of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane. The results suggest a need to study the pre-decomposition states on thermal decomposition of the nitramines' molecule's crystals.

关键词：爆破器料含能材料材料烟火材料

Effect of energy content of the nitraminic plastic bonded explosives on their performance and sensitivity characteristics

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Defence Technology（防务技术） 2019年第4期15卷 488-494页

作者： Svatopluk zeman Ahmed K. Hussein Marcela Jungova Ahmed Elbeih Institute of Enegetic Materials Faculty of Chemical Technology University of Pardubice CZ-532 10 Pardubice Czechia Military Technical College Kobry Elkobbah Cairo Egypt

Information about the forty nine nitraminic plastic bonded explosives(PBXs)and different nitramines were *** of these PBXs are nitramines 1,3,5-trinitro-1,3,5-triazinane(RDX)and β-1,3,5,7-tetranitro-1,3,5-tetrazocane(β-HMX),cis-1,3,4,6-tetranitro-octahydroimidazo-[4,5-d]imidazole(bicyclo-HMX,BCHMX)and e-2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane(e-HNIW,CL-20)which are bonded by polyfluoro-elastomers,polydimethyl-siloxane,poly-glycidyl azide,polyisobutylene,polystyrene-butadiene,poly-acrylonitrile-butadiene and hydroxyl-terminated polybutadiene in addition to a melt cast compositions based on 2,4,*** thirty two of these PBXs the relationships are specified and analyzed between heats of their combustion and relative explosive strengths;by means of these relationships it might be possible to estimate,which groupings in the macromolecule of binder could be liable to their primary fission in the PBXs ***,for forty two of these explosives,the relationships are described and analyzed between their enthalpies of formation and impact sensitivities;here is especially attention paid to PBXs filled by *** rate constants from Vacuum Stability Test(VST)of four nitramines and twenty PBXs are introduced into relationships with their enthalpies of *** to all the mentioned cases,increasing of energy content of the studied explosives leads to increase of the relative explosive strength or initiation reactivity,*** with the opposite trend,the outputs of VST are for BCHMX,where in PBXs are matrices with the esteric plasticizers or the energetic poly-glycidyl *** of RDX or HMX,respectively,into the BCHX PBXs gives ternary PBXs whose thermal stability,in the sense of applied VST,is higher comparing to the original binary explosives.

关键词： Enthalpy Explosive strength Combustion Nitramines PBX Thermal stability

新时期家庭经济困难毕业生就业流向特征实证分析——以广东某高校为例

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广东石油化工学院学报 2024年第2期34卷 65-71页

作者：邱一富林泽曼张法清广东石油化工学院马克思主义学院广东茂名525000 广东石油化工学院自动化学院广东茂名525000 广东石油化工学院学生工作部广东茂名525000

基于广东某高校2019—2020年本科家庭经济困难毕业生的就业流向数据,采用二分类logit模型分析该校家庭经济困难毕业生就业单位流向、行业流向以及地域流向特征。结果显示:高校办学定位、行业特色、性别、专业、地区经济发展水平等对家... 详细信息

基于广东某高校2019—2020年本科家庭经济困难毕业生的就业流向数据,采用二分类logit模型分析该校家庭经济困难毕业生就业单位流向、行业流向以及地域流向特征。结果显示:高校办学定位、行业特色、性别、专业、地区经济发展水平等对家庭经济困难毕业生的就业单位流向、行业流向、地域流向有不同程度的影响;尽管经济发达地区对家庭经济困难毕业生具有较强的“虹吸”作用,但家庭经济困难毕业生生源回流的特征仍较为明显;家庭经济困难毕业生中,党员毕业生具有一定就业偏好,更倾向于流向传统“优质就业”领域。结合分析有如下启示:对于地方行业特色型高校,发掘行业优势有助于促进高校家庭经济困难毕业生就业;掌握高校家庭经济困难毕业生就业流向特征有利于帮助高校构建“精准化”“全程化”“信息化”等五化协同的就业帮扶长效机制;对于家庭经济困难毕业生帮扶,既要强化就业指导,消除信息不对称所导致的竞争劣势,又要帮助其提早开展生涯规划,激发学习动力,提升综合竞争力。

关键词：就业流向特征经济困难毕业生行业特色高校 logit模型

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