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Effect of Y_2O_3 and Total Oxide Addition on Mechanical Properties of Pressureless Sintered β-SiC

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Journal of Materials Science & Technology 2003年第3期19卷 193-196页

作者： vladimir D.Krstic Centre for Manufacturing of Advanced Ceramics and Nanomaterials Queen’s UniversityNicol HallKingstonOntarioCanada K7L 3N6

The effect of Y203 and the total oxide volume fraction (Y203+AI203) on density and mechanical properties of low temperature (1770-1940℃) pressureless sintered β-SiC ceramics were presented. The optimum temperature for pressureless sintering of β-SiC was found to be -1850℃ and the optimum content of Y203 in the oxides was found to be between 40 and 57 wt pct. The highest sintered density was achieved by adding oxides at 14 vol. pct. Both of the highest strength and fracture toughness were achieved at -14 vol. pct oxide addition and yttria concentrations between 40 and 57 wt pct in the oxides. Hardness, on the other hand, was found to be the highest for samples with 14 vol. pct oxide addition and -64 wt pct Y2O3 in oxides.

关键词： Y_2O_3 SiC Mechanical properties Sintering

Experimental study of coal fracture dynamics under the influence of cyclic freezing-thawing using shear elastic waves

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International Journal of Coal Science & Technology 2021年第4期8卷 562-574页

作者： Petr V.Nikolenko Svetlana A.Epshtein vladimir l.Shkuratnik Polina S.Anufrenkova Polina Scientific and Training Testing laboratory of Physics and Chemistry of Coals National University of Science and Technology MISiSMoscowRussian Federation 119049 S.Anufrenkova1

Cyclic freezing-thawing can lead to fracture development in coal,affecting its mechanical and consumer *** study crack formations in coal,an ultrasonic sounding method using shear polarized waves was *** of three coal types(anthracite,lignite and hard coal)were *** research results show that,in contrast to the shear wave velocity,the shear wave amplitude is extremely sensitive to the formation of new cracks at the early stages of cyclic *** also show an inverse correlation between coal compressive strength and its tendency to form cracks under temperature impacts;shear wave attenuation increases more sharply in high-rank coals after the first freezing *** analysis of the received signals also confirmed significant crack formation in anthracite after the first freeze-thaw *** initial anisotropy was determined,and its decrease with an increase in the number of freeze-thaw cycles was *** data obtained forms an experimental basis for the development of new approaches to preserve coal consumer properties during storage and transportation under severe natural and climatic conditions.

关键词： Coal Cyclic freezing-thawing Ultrasonic Shear wave Fracture dynamics

Fragmentation model for large l/D (length over Diameter) explosive fragmentation warheads

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Defence Technology（防务技术） 2017年第4期13卷 300-309页

作者： vladimir M. Gold US Army RDECOM-ARDEC Attn: RDAR-MEE-F Picatinny Arsenal NJ 07806-5000 USA

New advanced numerical computer model enabling accurate simulation of fragmentation parameters of large length over Diameter(l/D)explosively driven metal shells has been developed and *** newly developed large l/D multi-region model links three-dimensional axisymmetric high strain high strain-rate hydrocode analyses with the conventional set of Picatinny Arsenal FRAGmentation(PAFRAG)simulation *** standard PAFRAG modeling technique is based on the Mott's theory of break-up of idealized cylindrical"ring-bombs",in which the length of the average fragment is a function of the radius and velocity of the shell at the moment of break-up,and the mechanical properties of the *** the newly developed multi-region model,each of the shell region,the break-up is assumed to occur instantaneously,whereas the entire shell is modeled to fragment at multiple times,according to the number of the regions *** to PAFRAG methodology,the required input for both the natural and the controlled fragmentation models including the geometry and the velocity of the shell at moment of break-up had been provided from the hydrocode analyses and validated with available experimental *** newly developed large l/D multi-region PAFRAG model has been shown to accurately reproduce available experimental fragmentation data.

关键词： Explosive fragmentation modeling Natural fragmentation Mott model PAFRAG Fragmentation warhead lethality performance

Solving the Faddeev-Merkuriev Equations in Total Orbital Momentum Representation via Spline Collocation and Tensor Product Preconditioning

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Communications in Computational Physics 2021年第6期30卷 255-287页

作者： Vitaly A.Gradusov vladimir A.Roudnev Evgeny A.Yarevsky Sergey l.Yakovlev Department of Computational Physics St Petersburg State UniversitySt Petersburg 199034Russia

The computational approach for solving the Faddeev-Merkuriev equations in total orbitalmomentum representation is *** equations describe a systemof three quantumcharged particles and arewidely used in bound state and scattering *** approach is based on the spline collocation method and exploits intensively the tensor product formof discretized operators and preconditioner,which leads to a drastic economy in both computer resources and time.

关键词： Faddeev-Merkuriev equations total orbital momentum representation spline collocation tensor product preconditioner

Method and portable facility for measurement of trace element concentration in prostate fluid samples using radionuclideinduced energy-dispersive X-ray fluorescent analysis

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Nuclear Science and Techniques 2016年第6期27卷 93-100页

作者： vladimir Zaichick Sofia Zaichick German Davydov Radionuclide Diagnostics Department Medical Radiological Research Centre Department of Medicine College of Medicine at ChicagoUniversity of Illinois

A facility and method for109 Cd radionuclide-induced energy-dispersive X-ray fluorescent(EDXRF) were developed to determine the Fe,Zn,Br,Rb,and Sr concentrations in the specimens of human prostatic *** of expressed prostatic fluid were obtained from 51 men(mean age 51 years,range 18–82 years) with apparently normal prostates using standard rectal massage *** values(M ± SEl) for concentration of trace elements(mg l^(-1)) in human prostate fluid were:Fe 9.04 ±1.21,Zn 573 ± 35,Br 3.58 ± 0.59,Rb 1.10 ± 0.08,and Sr B *** was shown that the results of trace element analysis in the micro-samples(20 l l) are sufficiently representative for assessment of the Fe,Zn,Br,and Rb concentration in the prostate *** facility for109 Cd radionuclide-induced EDXRF is comparatively compact and can be located in close proximity to the site of carrying out the massage *** means of Zn and Rb concentration obtained for prostate fluid agree well with median of reported *** the first time,the Fe and Br concentrations,as well as the upper limit of the Sr concentration,were determined in the human prostate fluid.

关键词：能量色散X射线荧光分析放射性核素元素浓度便携式设备前列腺测定样品诱导

Postoperative change of anti-Thomsen-Friedenreich and Tn IgG level: The follow-up study of gastrointestinal cancer patients

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World Journal of Gastroenterology 2008年第27期14卷 4352-4358页

作者： Eugeniy P Smorodin Oleg A Kurtenkov Boris l Sergeyev Kristel E Kodar Valentin I Chuzmarov vladimir P Afanasyev Department of Oncology & Immunology National Institute for Health Development Oncological Centre North-Estonian Regional Hospital

AIM: To study the influence of tumor removal on the serum level of IgG antibodies to tumor-associated Thomsen-Friedenreich (TF), Tn carbohydrate epitopes and xenogeneic αGal, and to elucidate on the change of the level during the follow-up as well as its association with the stage and morphology of the tumor and the values of blood parameters in gastrointestinal cancer. METHODS: Sixty patients with gastric cancer and 34 patients with colorectal cancer in stages Ⅰ-Ⅳ without distant metastases were subjected to follow- up. The level of antibodies in serum was determined by the enzyme-linked immunosorbent assay (ElISA) using synthetic polyacrylamide (PAA) glycoconjugates. Biochemical and haematological analyses were performed using automated equipment. RESUlTS: In gastrointestinal cancer, the TF antibody level was found to have elevated significantly after the removal of G3 tumors as compared with the preoperative level (u = 278.5, P level was elevated in the majority of gastric cancer patients (sign test, 20 vs 8, P ly). In gastrointestinal cancer, the elevated postoperative level of TF, Tn and αGal antibodies was noted in most patients with G3 tumors (sign test, 22 vs 5, P ly), but the elevation was not significant in patients with G1 + G2 resected tumors. The postoperative follow-up showed that the percentage of patients with G3 resected tumors of the digestive tract, who had a mean level of anti-TF IgG above the cut- off value (1.53), was significantly higher than that of patients with G1 + G2 resected tumors (χ2 = 3.89, all patients; χ2 = 5.34, patients without regional lymph node metastases; P level remained above the cut-off value (1.26), was significantly higher than that of patients with the cancer in stages Ⅲ-Ⅳ (χ2 = 4.71, gastric canc

关键词： IgG antibodies Thomsen-Friedenreich Tn αGal Gastrointestinal cancer Immunosuppression CA 19-9

Repeated penile girth enhancement with biodegradable scaffolds： microscopic ultrastructural analysis and surgical benefits

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Asian Journal of Andrology 2018年第5期20卷 488-492页

作者： Miroslav l Djordjevic Uros Bumbasirevic Borko Stojanovic Tamara Kravic Stevovic Tamara Martinovic Marta Bizic vladimir Kojovic School of Medicine University of Belgrade Belgrade 11000 Serbia University Children's Hospital Belgrade 11000 Serbia Institute for Urology Clinical Center ofSerbia Belgrade 11000 Serbia

Autologous tissue engineering using biodegradable scaffolds as a carrier is a well-known procedure for penile girth enhancement. We evaluated a group of previously treated patients with the aim to analyze histomorphometric changes after tissue remodeling and to estimate the benefits of repeated procedure. Between February 2012 and December 2016, a group of 21 patients, aged 22-37 （mean 28.0） years, underwent a repeated penile girth enhancement procedure with biodegradable scaffolds. Procedure included insertion of two poly-lactic-co-glycolic acid scaffolds seeded with laboratory-prepared fibroblasts from scrotal tissue specimens. During this procedure, biopsy specimens of tissue formed after the first surgery were taken for microscopic analysis. The mean follow-up was 38 months. Connective tissue with an abundance of connective tissue fibers, small blood vessels, and inflammatory cells were observed in all analyzed surgically removed tissue. Ultrastructural analysis of these tissue samples discovered the presence of large quantities of collagen fibrils running parallel to each other, forming bundles, with a few widely spread fibroblasts. In total, the mean values of flaccid and erect gain in girth after the second surgery were 1.1 ± 0.4 （range： 0.6- 1.7） cm and 1.0±0.3 （range： 0.6-1.5） cm, respectively. Microscopic evaluation of newly formed tissue, induced by autologous tissue engineering using biodegradable scaffolds, showed the presence of vascularized loose connective tissue with an abundance of collagen fibers, fibroblasts, and inflammatory cells, indicating active neovascularization and fibrinogenesis. The benefit of the repeated enhancement procedure was statistically significant.

关键词： biodegradable scaffolds microscopy penile enhancement tissue engineering

Pediatric GNAO1 encephalopathies:from molecular etiology of the disease to drug discovery

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Neural Regeneration Research 2023年第10期18卷 2188-2189页

作者： vladimir l.Katanaev Jana Valnohova Denis N.Silachev Yonika A.larasati Alexey Koval Translational Research Centre in Oncohaematology Department of Cell Physiology and MetabolismFaculty of MedicineUniversity of GenevaGenevaSwitzerland Institute of life Sciences and Biomedicine Far Eastern Federal UniversityVladivostokRussia Department of Functional Biochemistry of Biopolymers A.N.Belozersky Research Institute of Physico-Chemical BiologyMoscow State UniversityMoscowRussia

Gao is the major G protein in neurons,where it transduces signals from numerous G proteincoupled receptors(GPCRs)such as D2 dopamine,μ-opioid,M2 muscarinic,or α2-adrenergic *** 2013,the first mutations in GNAO1,the gene encoding Gao,were described in pediatric patients with encephalopathies(Nakamura et al.,2013),suffering from movementdisorders,epileptic seizures。

关键词： encephalo opioid

Hydrogen generating patch improves skin cell viability,migration activity,and collagen expression

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再生工程(英文) 2020年第1期1卷 1-5页

作者： Marina Safonov Jing You Jihyung lee vladimir l.Safonov Diana Berman Donghui Zhu H2 Universe llC GranburyTX 76049USA Department of Biomedical Engineering University of North TexasDentonTX 76203USA Materials Science and Engineering University of North TexasDentonTX 76203USA Department of Biomedical Engineering Stony Brook UniversityStony BrookNY 11794

Molecular hydrogen recently attracted lots of attention in biomedical community because of its abilities to mod-ulate signal transduction,protein phosphorylation,and gene expression that enable its anti-inflammatory,anti-allergy,and anti-apoptotic ***,controllable and local delivery of hydrogen molecules to tissues still remains ***,we propose a new method of delivering molecular hydrogen directly to human skin cells by designing a hydrogen-generating patch that releases hydrogen in surrounding environment as a product of chemical reaction of aluminum and carbon hydroxide in presence of *** show that in the pres-ence of molecular hydrogen the cells viability,expression of collagen,and migration efficiency of cells increase,thus suggesting that hydrogen can be used to promote better and faster healing of skin issues such as wounds and bruises.

关键词： Hydrogen Skin Cell Collagen Viability