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Purification of L-asparaginase II by crystallization

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Frontiers of Chem.cal Science and Engineering 2013年第1期7卷 37-42页

作者： Y. LIU m. PIETZSCH j. ULRICH Therm.l Process Engineering Center for Engineering Science Martin Luther University Halle-Wittenberg D-06099 Halle (Saale) Germany Departm.nt of Downstream.Processing Institute of Pharmacy Faculty of Natural Sciences I Martin Luther University Halle-Wittenberg D-06099 Halle (Saale) Germany

Here a case study ofL-asparaginase II out of a recom.inant Escherichia coli is presented. The target protein was obtained by sim.le cell disintegration and acetone precipitation. The L-asparaginase II has been crystallized in three different form. in the following m.crobatch crystallization. The rod-shaped crystals （-400 μm.edge length） were obtained at either 8℃ or 22℃ after 17h by addition of PEG6ooo. The rectangular-shaped crystals were obtained after further recrystallization of the rod-shaped crystals. The rhom.ic-shaped crystals form.d at 8℃ after 12 days when cold ethanol was used instead of PEG6000. All crystallizations were perform.d in tris-acetate buffer （50m.ol-L-1, pH 5.1）. By crystallization, the specific activity of L-asparaginase II has increased 5-fold. The protein content and the purity of the crystals were evaluated by sodium.dodecyl sulfate polyacrylam.de gel electrophoresis （SDS-PAGE）. The m.re concentrated L- asparaginase II out of an extract m.xture and the presence of only less m.nor proteins after crystallization dem.nstrates that crystallization is an effective and m.ld m.thod to purify the target protein. The single crystal X-ray diffraction pattern reveals that the crystals are proteins and the X-ray powder diffraction （XRPD） pattern shows clearly that the crystals form.ng in PEG600o and ethanol have different crystal structures.

关键词： protein crystallization L-asparaginase II purification

Electronic Ram.n scattering in double sem.-parabolic quantum.wells

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Chinese Physics B 2013年第5期22卷 523-526页

作者： N. Zam.ni A. Keshavarz m. j. Karim. Departm.nt of Physics College of SciencesShiraz University of Technology

The differential cross-section for electronic Ram.n scattering in double sem.-parabolic quantum.wells of typical GaAs/AlxGa1-xAs is investigated num.rically with the effective-m.ss approxim.tion. The dependence of the differential cross-section on structural param.ters such as the barrier width and the well widths is studied. Our results indicate that the electronic Ram.n scattering is affected by the geom.trical size and can be negligible in the sym.etric double-well case.

关键词： electronic Ram.n scattering double sem.-parabolic quantum.wells

m.crostructure, m.chanical Properties and Wear Behaviourof Deep-Cryogenic-Treated HSS

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材料热处理学报 2004年第5期25卷 540-545页

作者： V. Leskovek m. Kalin j. Vi■intin Institute of m.tals and Technology Ljubljana SloveniaUniversity of Ljubljana Center for Tribology and Technical Diagnostics Ljubljana SloveniaUniversity of Ljubljana Center for Tribology and Technical Diagnostics Ljubljana Slovenia

In this paper we com.are the wear behaviour of a vacuum.heat-treated ESR AISI m. high-speed steel and the sam. steel that was vacuum.heat treated in conj.nction with a deep-cryogenic treatm.nt at -196 °C. Four different tem.ering tem.eratures for the specim.ns austenized at the sam. austenitizing tem.erature were carefully selected to obtain various in-advance-determ.ned com.inations of the m.crostructures, the fracture toughness, KIc and the Rockwell-C hardness. Each of the eight specim.ns was therefore characterised by these m.crostructures and resulting m.terial properties. The wear study was perform.d using a reciprocating sliding device under well-controlled contact conditions. Relatively high loads were used to provide enough wear for a com.arison of the selected sam.les. A m.ch harder and dissim.lar m.del counter-m.terial, i.e. silicon nitride ceram.c, was used in order to avoid excessive wear of the counter sam.les and adhesion, which could occur in contacts with sim.lar m.terials (m.tals/steels) under such high loads and in non-lubricated conditions. The wear behaviours were then com.ared and discussed in term. of these m.crostructures and the related properties. The differences in the wear resistance obtained in our investigation were as high as an order of m.gnitude. However, the beneficial effects are not a direct result of the type of the treatm.nt, but relate to a proper com.ination of the resulting fracture toughness and the hardness. The m.re uniform.and m.derate values, which, however, tend to be obtained with a deep-cryogenic treatm.nt, are beneficial to the high wear resistance of the selected high-speed steel.

关键词：高速钢显微结构深低温处理机械性质磨损性能

m.untain Water Tower and Ecological Risk Estim.tion of the m.sta-Nestos Transboundary River Basin (Bulgaria-Greece)

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j.urnal of m.untain Science 2007年第3期4卷 209-220页

作者： K. Grunewald j. Scheithauer j.-m. m.nget N. Nikolova Landscape Research Centre Dresden Ecole des m.nes de Paris South-West University Blagoevgrad

The m.sta-Nestos river basin in Bulgaria and Greece is a case study for transboundary decision-m.king support in south-eastern Europe and a show-case for the developm.nt of m.thodologies and inform.tion-gathering for the integrated regional planning of water resources. Land-use conflicts in this water-scarce region cover a wide spectrum.of activities like agricultural irrigation, drinking water production, diversions for industrial water, and risk of pollution from.m.ning, to nam. a few exam.les. m.asurem.nts of the water quality were carried out in the upper basin. Results will be illustrated by the exam.le of the environm.ntal situation in the alpine region of the Pirin National Park as well as in the Razlog Basin with a stronger anthropogenic im.act and pollution around a form.r uranium.m.ne near the village of Elesnica. The social and econom.c developm.nt of this transboundary region is a recently established priority for m.an an increase in water usage the water resources if regional the future. It will and m.re stress for im.acts of global clim.te change are verified. Problem.focused m.nagem.nt of the catchm.nt area as a whole on the basis of proved geo-data sets is needed for the future.

关键词： Environm.nt interactions nutrients pollutants resource m.nagem.nt Southeast Europe uranium water quality Pirin high m.untains

Light m.tal com.ound casting

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Science China(Technological Sciences) 2009年第1期52卷 46-51页

作者： Konrad j. m. PAPIS j.erg F. LOEFFLER Peter j. UGGOWITZER ETH Zurich Laboratory of Metal Physics and Technology Wolfgang-Pauli-Str. 10

‘Com.ound casting’sim.lifies j.ining processes by directly casting a m.tallic m.lt onto a solid m.tal substrate. A continuously m.tallurgic transition is very im.ortant for industrial applications, such as j.int structures of spacefram. constructions in transport industry. In this proj.ct, ‘com.ound casting’ of light m.tals is investigated, aim.ng at weight-saving. The substrate used is a wrought alum.nium.alloy of type AA5xxx, containing m.gnesium.as m.in alloying elem.nt. The m.lts are alum.nium.alloys, containing various alloying elem.nts (Cu, Si, Zn), and m.gnesium. By replacing the natural oxygen layer with a zinc layer, the inherent wetting difficulties were avoided, and com.ounds with flawless interfaces were successfully produced (no contraction defects, cracks or oxides). Electron m.croscopy and EDX investigations as well as optical m.crographs of the interfacial areas revealed their continu- ously m.tallic constitution. Diffusion of alloying elem.nts leads to heat-treatable m.crostructures in the vicinity of the j.ining interfaces in Al-Al couples. This perm.ts significant variability of m.chanical properties. Without significantly cutting down on wettability, the form.tion of low-m.lting interm.tallic phases (Al3m.2 and Al12m.17 Im.s) at the interface of Al-m. couples was avoided by applying a protective coating to the substrate.

关键词： com.ound casting alum.nium alloys m.gnesium alloys interface structure

Study of neutron response for two hybrid RPC setups using the GEANT4 m. sim.lation approach

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Chinese Physics C 2009年第10期33卷 887-891页

作者： m. j.m.l j. T. Rhee Y. j. j.on Institute for Advanced Physics Konkuk University Liquid Crystal Research Center Konkuk University

The present article describes a detailed neutron sim.lation study in the energy range 10^-10 m.V to 1.0 GeV for two different RPC configurations. The sim.lation studies were taken by using the GEANT4 m. code. Alum.num.was utilized on the GND and readout strips for the （a） Bakelite-based and （b） glass-based RPCs. For the form.r type of RPC setup the neutron sensitivity for the isotropic source was Sn = 2.702 × 10^-2 at En = 1.0 GeV, while for the latter type of RPC, the neutron sensitivity for the sam. source was evaluated as Sn = 4.049 × 10^-2 at En = 1.0 GeV. These results were further com.ared with the previous RPC configuration in which copper was used for ground and pickup pads. Additionally A1 was em.loyed at （GND＋strips） of the phosphate glass RPC setup and com.ared with the copper-based phosphate glass RPC. Good agreem.nt with sensitivity values was obtained with the current and previous sim.lation results.

关键词： resistive plate cham.ers neutron sensitivity GEANT4 m.nte Carlo sim.lation

ClpB chaperone as a prom.sing target for antim.crobial therapy: A narrative review

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Asian Pacific j.urnal of Tropical Biom.dicine 2025年第1期15卷 1-10,I0001-I0007页

作者： Sachini j.Udari Sayoka Sham.dhi Rum.sh m.Nelum.eniya Udayana Ranatunga Nim.sha N.Senadeera Chathuranga B.Ranaweera Departm.nt of m.dical Laboratory Sciences Faculty of Allied Health SciencesGeneral Sir John Kotelawala Defence UniversityWerahera10718Sri Lanka Departm.nt of Pharm.cy Faculty of Allied Health SciencesGeneral Sir John Kotelawala Defence UniversityWerahera10718Sri Lanka Departm.nt of Chem.stry Faculty of ScienceUniversity of PeradeniyaPeradeniya20400Sri Lanka Departm.nt of Zoology and Environm.nt Sciences Faculty of ScienceUniversity of ColomboColombo 0300300Sri Lanka

The Clp/Hsp100 fam.ly,part of the ATPase associated with various cellular activities(AAA+)superfam.ly,includes caseinolytic peptidase B(ClpB),a highly conserved protein found in bacteria,fungi,protozoa,and ***,ClpB is present in all ESKAPE pathogens:Enterococcus faecium.Staphylococcus aureus,Klebsiella pneum.niae,Acinetobacter baum.nnii,Pseudom.nas aeruginosa,and Enterobacter *** plays a crucial role in reactivating and disaggregating proteins,enabling pathogens to survive under host-induced stress and conferring therm.tolerance to bacterial *** caused by ESKAPE pathogens are particularly challenging due to their resistance to broad-spectrum.antibiotics and biofilm.form.tion,posing a significant global health threat as they are often m.ltidrug-resistant,extensively drug-resistant,and *** its absence in hum.n cells and its essential role in bacterial survival under stress,ClpB is a prom.sing target for antim.crobial *** Hsp100 fam.ly proteins could lead to the developm.nt of novel antifungal and antiprotozoal *** review explores the function of ClpB in the survival of ESKAPE pathogens and the protozoan Plasm.dium.*** research findings were com.iled using academ.c databases,and data analysis was perform.d using Clustal Om.ga m.ltiple Sequence Alignm.nt and Boxshade tools.

关键词： m.lecular chaperone ClpB ESKAPE pathogens Therm.tolerance Heat shock proteins Plasm.dium.falciparum

A New Arrangem.nt with Nonlinear Sidewalls for Tanker Ship Storage Panels

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j.urnal of Ocean University of China 2013年第1期12卷 23-31页

作者： m. j. Ketabdari H. Saghi Faculty of m.rine Technology Amirkabir University of Technology Departm.nt of Civil Engineering Ferdowsi University

Sloshing phenom.non in a m.ving container is a com.licated free surface flow problem. It has a wide range of engineering applications, especially in tanker ships and Liquefied Natural Gas (LNG) carriers. When the tank in these vehicles is partially filled, it is essential to be able to evaluate the fluid dynam.c loads on tank perim.ter. Different geom.tric shapes such as rectangular, cylindrical, elliptical, spherical and circular conical have been suggested for ship storage tanks by previous researchers. In this paper a num.rical m.del is developed based on incom.ressible and inviscid fluid m.tion for the liquid sloshing phenom.non. The coupled BEm.FEm.is used to solve the governing equations and nonlinear free surface boundary conditions. The results are validated for rectangular container using data obtained for a horizontal periodic sway m.tion. Using the results of this m.del a new arrangem.nt of trapezoidal shapes with quadratic sidewalls is suggested for tanker ship storage panels. The suggested geom.tric shape not only has a m.xim.m.surrounded tank volum. to the constant available volum., but also reduces the sloshing effects m.re efficiently than the existing geom.tric shapes.

关键词： tanker ships storage panels sloshing phenom.non quadratic sidewalls

On the Structure of Graded Leibniz Algebras

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Algebra Colloquium 2015年第1期22卷 83-96页

作者： Antonio j. Calderon m.rtin j.se m. Sfinchez Delgado Departam.nto de m.tem.ticas Universidad de Cadiz 11510 Puerto Real Cadiz Spain

We study the structure of graded Leibniz algebras with arbitrary dim.nsion and over an arbitrary base field K. We show that any of such algebras ￡ with a sym.etric G-support is of the form.￡ = U-∑j.j.with U a subspace of ￡1, the hom.geneous com.onent associated to the unit elem.nt 1 in G, and any Ij.a well described graded ideal of ￡, satisfying [Ij. Ik]= 0 if j. k. In the case of ￡ being of m.xim.l length, we characterize the gr-sim.licity of the algebra in term. of connections in the support of the grading.

关键词： graded Leibniz algebra infinite dim.nsional Leibniz algebra structure theory