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Silk-based nerve guidance conduits with macroscopic holes modulate the vascularization of regenerating rat sciatic nerve

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neural Regeneration Research 2025年第6期20卷 1789-1800页

作者： Carina Hromada Patrick Heimel Markus kerbl LászlóGál Sylvia nürnberger barbara Schaedl James Ferguson nicole Swiadek Xavier Monforte Johannes C.Heinzel Antal nógrádi Andreas H.Teuschl-Woller David Hercher Department Life Science Engineering University of Applied Sciences Technikum WienViennaAustria Austrian Cluster for Tissue Regeneration ViennaAustria Ludwig boltzmann Institute for Traumatology The Research Center in Cooperation with AUVAViennaAustria University Clinic of Dentistry Medical University of ViennaViennaAustria Department of Plastic Reconstructive and Aesthetic SurgeryLandesklinikum Wiener Neustadt2700 Wiener NeustadtAustria Department of Anatomy Histology and EmbryologyAlbert Szent-Györgyi Medical SchoolUniversity of SzegedSzegedHungary Medical University of Vienna Department of Orthopedics and Trauma SurgeryDevision of Trauma SurgeryViennaAustria Department of Hand- PlasticReconstructive and Burn SurgeryBG Unfallklinik TuebingenUniversity of TuebingenTuebingenGermany

Peripheral nerve injuries induce a severe motor and sensory deficit. Since the availability of autologous nerve transplants for nerve repair is very limited, alternative treatment strategies are sought, including the use of tubular nerve guidance conduits(tnGCs). However, the use of tnGCs results in poor functional recovery and central necrosis of the regenerating tissue, which limits their application to short nerve lesion defects(typically shorter than 3 cm). Given the importance of vascularization in nerve regeneration, we hypothesized that enabling the growth of blood vessels from the surrounding tissue into the regenerating nerve within the tnGC would help eliminate necrotic processes and lead to improved regeneration. In this study, we reported the application of macroscopic holes into the tubular walls of silk-based tnGCs and compared the various features of these improved silk^(+) tnGCs with the tubes without holes(silk^(–) tnGCs) and autologous nerve transplants in an 8-mm sciatic nerve defect in rats. Using a combination of micro-computed tomography and histological analyses, we were able to prove that the use of silk^(+) tnGCs induced the growth of blood vessels from the adjacent tissue to the intraluminal neovascular formation. A significantly higher number of blood vessels in the silk^(+) group was found compared with autologous nerve transplants and silk^(–), accompanied by improved axon regeneration at the distal coaptation point compared with the silk^(–) tnGCs at 7 weeks postoperatively. In the 15-mm(critical size) sciatic nerve defect model, we again observed a distinct ingrowth of blood vessels through the tubular walls of silk^(+) tnGCs, but without improved functional recovery at 12 weeks postoperatively. Our data proves that macroporous tnGCs increase the vascular supply of regenerating nerves and facilitate improved axonal regeneration in a short-defect model but not in a critical-size defect model. This study suggests that further optimizatio

关键词： axon regeneration blood vessel functional recovery macroporous nerve lesion peripheral nerve repair sciatic nerve silk-based nerve guidance conduit vascularization

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numerical simulation of the effect of gold doping on the resistance to neutron irradiation of silicon diodes

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Journal of Semiconductors 2015年第1期36卷 47-51页

作者： k.bekhouche n.Sengouga b.k.Jones Laboratory of Metallic and Semiconducting Materials (LMSM) Université de Biskra 07000 Biskra Algeria Department of Physics Lancaster University Lancaster LA5 9LX UK

We have carried out a numerical simulation of the effect of gold doping on the electrical characteristics of long silicon diodes exposed to neutron irradiation. The aim is to investigate the effect of gold on the hardness of the irradiated diodes. The reverse current voltage and capacitance voltage characteristics of doped and undoped diodes are calculated for different irradiation doses. The leakage current and the effective doping density are extracted from these two characteristics respectively. The hardness of the diodes is evaluated from the evolution of the leakage current and the effective doping density with irradiation doses. It was found that diodes doped with gold are less sensitive to irradiation than undoped ones. Thus gold appears to stabilise the electrical properties on irradiation. The conduction mechanism is studied by the evolution of the current with temperature. The evaluated activation energy indicates that as the gold doping or irradiation dose increases, the current switches from the basic diffusion to the generation-recombination process, and that it can even become ohmic for very high gold densities or irradiation doses.

关键词： silicon diodes gold doping numerical simulation

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Comparative study on glutathione transferases of rat brain and testis under the stress of phenobarbitol and β-methylcholanthrene

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Journal of Zhejiang University-Science b(biomedicine & biotechnology) 2005年第8期6卷 759-769页

作者： THYAGARAJU k HEMAVATHI b VASUnDHARA k RAO A.D DEVI k.n Department of biochemistry Sri Venkateswara UniversityTirupati 517 502 AP IndiaDepartment of Biochemistry Sri Venkateswara UniversityTirupati 517 502 AP IndiaDepartment of Biochemistry Sri Venkateswara UniversityTirupati 517 502 AP IndiaDepartment of Biochemistry Sri Venkateswara UniversityTirupati 517 502 AP IndiaDepartment of Biochemistry Sri Venkateswara UniversityTirupati 517 502 AP India

A comparative study was made on the tissue specific expression of glutathione transferases (GST) in brain and testis after exposure of rat to phenobarbitol (Pb) and β-methylcholanthrene (MC). Glutathione transferases, a family of multifunctional proteins are involved in intracellular transport processes and in detoxication of electrophilic xenobiotics by catalyzing reactions such as conjugation, isomerization, reduction and thiolysis. On purification, the yield of GST proteins by affinity chromatography was 39% in testis and 32% in brain. The affinity purified testis GSTs were resolved by chromatofocusing into six anionic and four cationic isozymes, and in brain glutathione transferases were resolved into four anionic and three cationic isozymes, suggesting the presence of multiple isozymes with Yc, Yb, Yβ and Yδ in both of them. In testis and brain, these isozymes at identical pI values showed variable functions with a battery of substrates and the cationic isozymes of brain and testis showed identical properties in CHP (cumene hydroperoxide) at pH values of above 7.0. Substrate specificity studies and immunoblot analysis of testis and brain proteins revealed that they play a predominant role in the detoxication of phenobarbitol or β-methylcholanthrene. Expression of the isozymes in testis and brain on exposure to Pb and MC indicated elevated subunit variation. In both testis and brain, Yδ of π class was expressed on Pb treatment and Yc of α class and Yβ of μ class was expressed in MC treated testis and only Yc was predominantly expressed in MC treated brain. Thus these subunits expression is considered as markers for carcinogenesis and specific to chemical toxicity under phenobarbitol and β-methylcholanthrene stress.

关键词： Glutathione transferases Testis brain Phenobarbitol β-Methylcholanthrene

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Enhanced green emission from La＿(0.4)F＿3:Ce＿(0.45),Tb＿(0.15)/TiO＿2 core/shell structure

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Journal of Rare Earths 2015年第1期33卷 20-26页

作者： T.k.Srinivasan b.S.Panigrahi n.Suriyamurthy P.k.Parida b.Venkatraman Indira Gandhi Centre for Atomic Research Kalpakkam–603102 India

nano sized La0.4F3：Ce0.45,Tb0.15（core）, La0.4F3：Ce0.45,Tb0.15（Ti O2）（core） shell, La0.55F：Ce0.45, and La0.85F3：Tb0.15 particles were synthesized by adopting co-precipitation technique in acidic environment and coated with Ti O2 to form a core-shell structure by adopting a mechanical dispersion method at room temperature. The synthesized materials were characterized using X-ray diffraction（XRD）, transmission electron microscopy（TEM）, Fourier transform infrared spectroscopy（FTIR）, ultraviolet-visible spectroscopy（UV-Vis） absorption, photoluminescence and lifetime spectroscopy. The crystal structure of La0.4F3：Ce0.45,Tb0.15 remained the same as La F3 after being doped with Ce and Tb ions but with a slight decrease in the lattice parameter. TEM image confirmed the formation of a core-shell structure. The La0.4F3：Ce0.45,Tb0.15/Ti O2 exhibited Tb3＋ fluorescence enhancement by a factor of 1.76. Scintillation from the synthesized materials was also observed under X-ray excitation.

关键词： core-shell cerium terbium luminescence lanthanum fluoride scintillation rare earths

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Thermophysical properties of iridium at finite temperature

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Chinese Physics b 2016年第11期25卷 404-411页

作者： Priyank kumar n k bhatt P R Vyas V b Gohel Department of Science Government PolytechnicGandhinagar Department of Physics Sardar Patel University Department of Physics School of Science Gujarat University

The bulk properties of materials in an extreme environment such as high temperature and high pressure can be understood by studying anharmonic effects due to the vibration of lattice ions and thermally excited *** this spirit,in the present paper,anharmonic effects are studied by using the recently proposed mean-field potential（MFP） approach and Mermin functional which arise due to the vibration of lattice ions and thermally excited electrons,*** MFP experienced by a wanderer atom in the presence of surrounding atoms is constructed in terms of cold energy using the local form of the *** have calculated the temperature variation of several thermophysical properties in an extreme environment up to melting *** results of our calculations are in excellent agreement with the experimental findings as well as the theoretical results obtained by using first principle *** conclude that presently used conjunction scheme（MFP＋pseudo potential） is simple computationally,transparent physically,and accurate in the sense that the results generated are comparable and sometimes better than the results obtained by first principle *** pseudopotential used is transferable to extreme environment without adjusting its parameters.

关键词： extreme experienced melting presently excited thermally sometimes understood comparable conclude

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Microstructure, properties and hot workability of M300 grade maraging steel

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Defence Technology（防务技术） 2018年第1期14卷 51-58页

作者： k.V.A.Chakravarthi n.T.b.n.koundinya S.V.S.narayana Murty b.nageswara Rao Materials and Mechanical Entity Vikram Sarabhai Space Centre Research scholar Department of Mechanical Engineering K L University Department of Metallurgical Engineering and Materials Science Indian Institute of Technology Department of Mechanical Engineering K L University

This paper presents isothermal uniaxial compression test results of M300 grade maraging steel over a wide range of temperatures(900 e1200℃) and strain rates(0.001 e100 s^(-1)) to examine hot deformability and concurrent microstructural evolution. Processing map is generated and indicated the optimum processing parameters in the temperature range of 1125℃-1200℃ and strain rate range of 0.001 e0.1 s^(-1). High values of the efficiency of power dissipation, microstructural observations and EbSD results indicate softening mechanism to be the occurrence of dynamic recrystallisation. Material constants in a constitutive relation are evaluated from the flow stress data useful in computer modelling.

关键词： Activation energy Constitutive relation Hot deformation M300 grade maraging steel Processing map

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Electron inelastic mean free paths in solids:A theoretical approach

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Chinese Physics b 2012年第9期21卷 208-214页

作者： Siddharth H.Pandya b.G.Vaishnav k.n.Joshipura Department of Physics Sardar Patel University Physical Research Laboratory

In the present paper, the inelastic mean free path （IMFP） of incident electrons is calculated as a function of energy for silicon （Si）, oxides of silicon （SiO2）, SiO, and A1203 in bulk form by employing atomic/molecular inelastic cross sections derived by using a semi-empirical quantum mechanical method developed earlier. A general agreement of the present results is found with most of the available data. It is of great importance that we have been able to estimate the minimum IMFP, which corresponds to the peak of inelastic interactions of incident electrons in each solid investigated. new results are presented for SiO, for which no comparison is available. The present work is important in view of the lack of experimental data on the IMFP in solids.

关键词： electron inelastic mean free path complex potential inelastic electron scattering cross sections solids

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The Fibrillar Matrix:novel Avenues for breast Cancer Detection and Treatment

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Engineering 2021年第10期7卷 1375-1380页

作者： Rasha Rezk Raquel Marín-García Annica k.b.Gad Weston Park Cancer Centre Department of Oncology and MetabolismThe Medical SchoolThe University of SheffieldSheffield S102RXUnited Kingdom Department of Engineering University of CambridgeCambridge CB21PZUnited Kingdom Madeira Chemistry Research Center University of MadeiraFunchal 9020105Portugal

breast cancer is marked by large increases in the protein fibers around tumor *** fibers increase the mechanical stiffness of the tissue,which has long been used for tumor diagnosis by manual *** research in bioengineering has led to the development of novel biomaterials that model the mechanical and architectural properties of the tumor microenvironment and can be used to understand how these cues regulate the growth and spread of breast ***,we provide an overview of how the mechanical properties of breast tumor tissues differ from those of normal breast tissue and noncancerous *** also describe how biomaterial models make it possible to understand how the stiffness and viscosity of the extracellular environment regulate cell migration and breast cancer *** highlight the need for biomaterial models that allow independent analysis of the individual and different mechanical properties of the tumor microenvironment and that use cells derived from different regions within *** models will guide the development of novel mechano-based therapies against breast cancer metastasis.

关键词： breast cancer Tissue stiffness Cancer metastasis Cell migration bioengineered scaffold Viscosity

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Simulation of the spatio-temporal evolution of the electron energy distribution function in a pulsed hollow-cathode discharge

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Plasma Science and Technology 2023年第3期25卷 87-94页

作者： n A ASHURbEkOV k O IMInOV k M RAbADAnOV G S SHAkHSInOV M Z ZAkARYAEVA M b kURbAnGADZHIEVA Dagestan State University Department of Physics Harbin Institute of Technology Institute of Physics Dagestan Federal Research CenterRussian Academy of Sciences

This article presents the 2D simulation results of a nanosecond pulsed hollow cathode discharge obtained through a combination of fluid and kinetic *** spatio-temporal evolution of the electron energy distribution function(EEDF)of the plasma column and electrical characteristics of the nanosecond pulsed hollow cathode discharge at a gas pressure of 5 Torr are *** results show that the discharge development starts with the formation of an ionization front at the anode *** ionization front splits into two parts in the cathode cavity while propagating along its lateral *** ionization front formation leads to an increase in the fast isotropic EEDF component at its front,as well as in the anisotropic EEDF *** accelerated electrons enter the cathode cavity,which significantly contributes to the formation of the highenergy EEDF component and EEDF anisotropy.

关键词： pulsed nanosecond discharge electron energy distribution fuinction hollow cathode electron kinetics gas discharge

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A novel numerical Method of O(h^(4))for Three-Dimensional non-Linear Triharmonic Equations

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Communications in Computational Physics 2012年第10期12卷 1417-1433页

作者： R.k.Mohanty M.k.Jain b.n.Mishra Department of Mathematics Faculty of Mathematical SciencesUniversity of DelhiDelhi-110007India Department of Mathematics Indian Institute of TechnologyHauz KhasNew Delhi-110016India Department of Mathematics Utkal UniversityVani ViharBhubaneswar-751004India 4076 C/4Vasant KunjNew Delhi-110070India Department of Mathematics Rajasunakhala CollegeNayagarhOrissa-752065India

In this article,we present two new novel finite difference approximations of order two and four,respectively,for the three dimensional non-linear triharmonic partial differential equations on a compact stencil where the values of u,δ^(2)u/δn^(2)andδ^(4)u/δn^(4)are prescribed on the *** introduce new ideas to handle the boundary conditions and there is no need to discretize the derivative boundary *** require only 7-and 19-grid points on the compact cell for the second and fourth order approximation,*** Laplacian and the biharmonic of the solution are obtained as by-product of the *** require only system of three equations to obtain the *** results are provided to illustrate the usefulness of the proposed methods.

关键词： Finite differences three dimensional non-linear triharmonic equations fourth order compact discretization Laplacian biharmonic maximum absolute errors

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