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Improvement in varistor properties of CaCu_(3)Ti_(1)O_(12) ceramics by chromium addition

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Journal of Materials Science & Technology 2020年第6期41卷 12-20页

作者： Edson Cezar Grzebielucka Joao Frederico haas Leandro Monteiro Eder Carlos Ferreira de Souza Christiane Philippini Ferreira Borges AndréVitor Chaves de Andrade Eloísa Cordoncillo héctor Beltrán-Mir Sandra Regina Masetto Antunes Programa Pós-Graduacao em Química Aplicada Universidade Estadual de Ponta GrossaAv.Gen.Carlos Cavalcanti 474884.030-000Ponta GrossaParanáBrazil Programa de Pós-Graduacao em Ciências/Física Universidade Estadual de Ponta GrossaAv.Gen.Carlos Cavalcanti 474884.030-000Ponta GrossaParanáBrazil Dpto.de Química Inorgánica y Orgánica Universitat Jaume IAv.de Vicent Sos Baynats/n12071Castellón de la PlanaSpain

The effect of chromium addition on the structure and electrical properties of CaCu3Ti4O12 is *** based on the formula CaCu3Ti4-xCrxO12-σ(x = 0, 0.025, 0.050 and 0.075 mol%) are prepared by solid-state reaction. Pellets sintered at 1070℃ for 12 h are characterised by X-ray diffraction, scanning electron microscopy/energy dispersive spectroscopy and impedance spectroscopy. Current densityelectric field, dielectric loss and permittivity measurements are also carried out. Rietveld refinement showed the substitution of Cr(Ⅲ) on the Ti(Ⅳ) site, with the maximum substitution for x = 0.025 mol%.The generation of electrical defects in the grain boundary region by chromium doping is responsible for increasing the electric breakdown field strength and nonlinearity coefficient at room temperature from 1723 V/cm and 5.29 for x = 0 mol% to 3431 V/cm and 8.16 for x = 0.025 mol%. This composition shows the greatest improvement in ceramic varistor parameters.

关键词： CCTO Structural analysis Impedance Varistor Rietveld

Gastric trichobezoar associated with perforated peptic ulcer and Candida glabrata infection

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World Journal of Clinical Cases 2014年第12期2卷 918-923页

作者： héctor Losada Morales Cecilia huenchullán Catalán Rodrigo Arriagada Demetrio Macarena Espinoza Rivas Natalia Castagnoli Parraguez Martín Alanis Alvarez Cirugía hepato-pancreática y Biliar Departamento de Cirugía Clínica Alemana de Temuco Temuco 4810297 Chile Cirugía hepato-pancreática y Biliar Departamento de Cirugía y Traumatología Universidad de La Frontera Temuco 4781218 Chile Departamento de Imágenes Clínica Alemana de Temuco Temuco 4810297 Chile Departamento de Ginecología y Obstetricia Clínica Alemana de Temuco Temuco 4810297Chile

Bezoars are accumulations of human or plant fiber located in the gastrointestinal tract of both humans and animals. Patients remain asymptomatic for several years, and the symptoms develop as these accumulations increase in size to the point of obstruction or perforation. We report the case of a 21-year-old patient at 10 d postpartum, who presented with acute abdomen associated with sepsis. Given the urgency of the clinical picture, at no point was the presence of a giant bezoar at gastric level suspected, specifically a trichobezoar. The emergency abdominal and pelvic ultrasound revealed only unspecific signs of perforated hollow viscus. Diagnosis was therefore made intraoperatively. A complete gastric trichobezoar was found with gastric perforation and secondary peritonitis. The peritoneal fluid culture revealed Candida glabrata.

关键词： Bezoar Postpartum period Acute abdomen

The spectrum of building block conformers sustains the biophysical properties of clinically-oriented self-assembling protein nanoparticles

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Science China Materials 2022年第6期65卷 1662-1670页

作者： Eric Voltà-Durán Julieta M Sánchez hèctor-López-Laguna Eloi Parladé Laura Sánchez-García Alejandro Sánchez-Chardi Ario de Marco Ugutz Unzueta Esther Vázquez Antonio Villaverde Institut de Biotecnologia i de Biomedicina Universitat Autònoma de BarcelonaBellaterra 08193BarcelonaSpain Departament de Genètica i de Microbiologia Universitat Autònoma de BarcelonaBellaterra 08193BarcelonaSpain CIBER de Bioingeniería Biomateriales y Nanomedicina(CIBER-BBN) Bellaterra 08193BarcelonaSpain Instituto de Investigaciones Biológicas y Tecnológicas(IIBYT)(CONICET-Universidad Nacional de Córdoba) ICTA&Cátedra de Química BiológicaDepartamento de QuímicaFCEFyNUNC.Av.Velez Sarsfield 1611X 5016GCA CórdobaArgentina Servei de Microscòpia Universitat Autònoma de BarcelonaBellaterra 08193BarcelonaSpain Departament de Biologia Evolutiva Ecologia i Ciències AmbientalsFacultat de BiologiaUniversitat de Barcelona08028 BarcelonaSpain Laboratory for Environmental and Life Sciences University of Nova GoricaNova Gorica 5000Slovenia Biomedical Research Institute Sant Pau(IIB Sant Pau) Sant Antoni Ma Claret 16708025 BarcelonaSpain

histidine-rich peptides confer self-assembling properties to recombinant proteins through the supramolecular coordination with divalent *** fact allows the cost-effective,large-scale generation of microscopic and macroscopic protein materials with intriguing biomedical *** such materials,resulting from the simple bioproduction of protein building blocks,homomeric nanoparticles are of special value as multivalent interactors and drug ***,we have here identified that the assembly of a given his-tagged protein might render distinguishable categories of self-assembling protein *** fact has been scrutinized through the nanobody-containing fusion proteins EM1-GFP-h6 and A3C8-GFP-h6,whose biosynthesis results in two distinguishable populations of building *** one of them,the assembling and disassembling is controllable by ***,a second population immediately self-assembles upon purification through a non-regulatable pathway,rendering larger nanoparticles with specific biological *** structural analyses of both model proteins and nanoparticles revealed important conformational variability in the building *** fact renders different structural and functional categories of the final soft materials resulting from the participation of energetically unstable intermediates in the oligomerization *** data illustrate the complexity of the hismediated protein assembling in recombinant proteins but they also offer clues for a better design and refinement of protein-based nanomedicines,which,resulting from biological fabrication,show an architectonic flexibility unusual among biomaterials.

关键词： recombinant proteins self-assembling protein materials nanoparticles biomaterials

how does high-intensity intermittent training affect recreational endurance runners? Acute and chronic adaptations: A systematic review

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Journal of Sport and health Science 2017年第1期6卷 54-67页

作者： Felipe García-Pinillos Víctor M.Soto-hermoso Pedro A.Latorre-Román Department of Corporal Expression University of Jaen Department of Sports Sciences University of Granada

Objective: This systematic review aimed to critically analyze the literature to determine how high-intensity intermittent training(hIIT) affects recreational endurance runners in the short-and ***: Electronic databases were searched for literature dating from January 2000 to October 2015. The search was conducted using the key words "high-intensity intermittent training" or "high-intensity interval exercise" or "interval running" or "sprint interval training" and "endurance runners" or "long distance runners". A systematic approach was used to evaluate the 783 articles identified for initial review. Studies were included if they investigated hIIT in recreational endurance runners. The methodological quality of the studies was evaluated using the Physiotherapy Evidence Database(PEDro) scale(for intervention studies) and the modified Downs and Black Quality Index(for cross-sectional studies).Results: Twenty-three studies met the inclusionary criteria for review. The results are presented in 2 parts: cross-sectional(n = 15) and intervention studies(n = 8). In the 15 cross-sectional studies selected, endurance runners performed at least 1 hIIT protocol, and the acute impact on physiological, neuromuscular, metabolic and/or biomechanical variables was assessed. Intervention studies lasted a minimum of 4 weeks, with 10 weeks being the longest intervention period, and included 2 to 4 hIIT sessions per week. Most of these studies combined hIIT sessions with continuous run(CR) sessions; 2 studies' subjects performed hIIT ***: hIIT-based running plans(2 to 3 hIIT sessions per week, combining hIIT and CR runs) show athletic performance improvements in endurance runners by improving maximal oxygen uptake and running economy along with muscular and metabolic adaptations. To maximize the adaptations to training, both hIIT and CR must be part of training programs for endurance runners.

关键词： Endurance high-intensity training Intermittent exercises Interval running Long-distance runners Running

Analysis of heterogeneous characteristics in a geothermal area with low permeability and high temperature

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Geoscience Frontiers 2017年第5期8卷 1039-1050页

作者： Alfonso Aragón-Aguilar Georgina Izquierdo-Montalvo Siomara López-Blanco Víctor Arellano-Gómez Instituto Nacional de Electricidad y Energías Limpias Reforma 113 Col.Palmira Cuernavaca Morelos CP 62490 Mexico

An analytical methodology for reservoir characterization was applied in the central and southwestern zones of Los humeros geothermal field(LhGF). This study involves analysis of temperature, pressure,enthalpy and permeability in wells and their distribution along the area. The wells located in the central western side of the geothermal field are productive, whereas those located at the central-eastern side are non-productive. Through temperature profiles, determined at steady state in the analyzed wells, it was observed that at bottom conditions(approximately 2300 m depth), temperatures vary between 280 and360℃. The temperatures are higher at the eastern side of central zone of LhGF. A review of transient pressure tests, laboratory measurements of core samples, and correlation of circulation losses during drilling suggest that permeability of the formation is low. The enthalpy behavior in productive wells shows a tendency of increase in the steam fraction. It was found that productivity behavior has inverse relation with permeability of rock formation. Further, it is observed that an imbalance exists between exploitation and recharge. It is concluded from the results that the wells located at central-eastern area have low permeability and high temperature, which indicates possibility of heat storage.

关键词： Los humeros geothermal field Reservoir performance hot rock Enthalpy Permeability Recharge

Engineering of Fuel Plates on Uranium-Molybdenum Monolithic: Critical Issues

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World Journal of Nuclear Science and Technology 2015年第4期5卷 274-286页

作者： Jaime Lisboa Jorge Marin Mario Barrera héctor Pesenti Departamento de Materiales Nucleares Comisión Chilena de Energía Nuclear CCHEN Santiago Chile Instituto de Materiales Facultad de Ingeniería Universidad Austral de Chile Valdivia Chile

Engineering of nuclear fuels using monolithic plates of uranium-molybdenum and Al-6061 cladding is the current challenge for research and test reactors. The main drawback of the manufacture of monolithic nuclear fuel was analyzed using two surface coating methods: aluminum sputtering and transient liquid phase bonding (TLPB). Coating was done with a commercial alloy of Al-Si (R-4047). These techniques were used to improve the metallurgical bonding between the UMo and the cladding by rolling. Finally, design parameters and manufacture of UMo plate fuels were established. Mechanical tests were used to characterize the plates, resulting in UTS values of about 700 and 1000 MPa for the UMo alloys. These results are complemented with metrological analyses, X-Ray diffraction (XRD), thermal analyses, and metallography. X-rays and ultrasound scanners were used to monitor bonding and the co-rolling effects. These initial results show the main obstacles to the engineering development of UMo monolithic plate fuels with Al-6061 cladding, and these are discussed herein.

关键词： Metallurgic Bonding Co-Rolling Monolithic UMo Aluminum Alloy Nuclear Fuel

Efficient handling of Lock hand-off in DSM Multiprocessors with Buffering Coherence Controllers

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Journal of Computer Science & Technology 2012年第1期27卷 75-91页

作者： Benjamín Sahelices Agustín de Dios Pablo Ibáez Víctor Vials-Yúfera José María Llabería Computer Science Department and hiPEAC European Network of Excellence University of Valladolid Valladolid Spain Computer Science and Systems Engineering Department I3A Research Institute and HiPEAC European Network of Excellence University of Zaragoza Zaragoza Spain Computer Architecture Department and hiPEAC European Network of Excellence Polytechnic University of Catalua Barcelona Spain

Synchronization in parallel programs is a major performance bottleneck in multiprocessor systems. Shared data is protected by locks and a lot of time is spent on the competition arising at the lock hand-off. In order to be serialized, requests to the same cache line can either be bounced （NACKed） or buffered in the coherence controller. In this paper, we focus mainly on systems whose coherence controllers buffer requests. In a lock hand-off, a burst of requests to the same line arrive at the coherence controller. During lock hand-off only the requests from the winning processor contribute to progress of the computation, since the winning processor is the only one that will advance the work. This key observation leads us to propose a hardware mechanism we call request bypassing, which allows requests from the winning processor to bypass the requests buffered in the coherence controller keeping the lock line. We present an inexpensive implementation of request bypassing that reduces the time spent on all the execution phases of a critical section （acquiring the lock, accessing shared data, and releasing the lock） and which, as a consequence, speeds up the whole parallel computation. This mechanism requires neither compiler or programmer support nor ISA or coherence protocol changes. By simulating a 32-processor system, we show that using request bypassing does not degrade but rather improves performance in three applications with low synchronization rates, while in those having a large amount of synchronization activity （the remaining four）, we see reductions in execution time and in lock stall time ranging from 14% to 39% and from 52% to 7170, respectively. We compare request bypassing with a previously proposed technique called read combining and with a system that bounces requests, observing a significantly lower execution time with the bypassing scheme. Finally, we analyze the sensitivity of our results to some key hardware and software parameters.

关键词： distributed shared memory multiprocessors synchronization buffer coherence controller request bypass

Isolation, Cultivation, and Morphological Characteristics of hair Follicle Adult Stem Cells in the Bulge Region in Mouse and human

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Microscopy Research 2020年第2期8卷 9-30页

作者： Bélgica J. Molina héctor J. Finol Center for Electron Microscopy Science Faculty Central University of Venezuela Caracas Venezuela Dermatology Service University Hospital of Caracas Caracas Venezuela

Skin contains various populations of stem cells (SCs). Among these are hair follicle stem cells (hFSCs) in the bulge region. The behavior of hFSCs deserves to be widely studied due to the benefits to be derived from their identification, isolation, and amplification. Skin samples of newborn mice (n = 32) and human adults (n = 10) were used, and the bulge region was isolated and cultured. The isolation and characterization of cells were conducted through immunocytochemistry and immunofluorescence, using mainly CD34 and CD200 monoclonal antibodies. Initially, cells grew slowly from the explant around the bulge region, accruing cells with different morphology in both mouse and human, latter being mostly polygonal;the mouse cells reaching confluence faster (5 to 7 days) than the human (12 to 15 days). It was possible to isolate into subcultures cells with small size (10 - 13 μm diameter), round-shape, scant cytoplasm, central prominent nucleus and with nucleolus, which formed colonies, maintaining their phenotype in a high proportion (77% - 83% and 91% in mouse and human, respectively), without showing changes in their morphology during almost 7 months in the mouse cells, and a month and a half in the human. These results demonstrate that the selection, the isolation, and the conditioned mediums allowed population increases of bulge cells and indicate that cultured cells may retain their sternness in that they maintained their phenotypic characteristics, expressed specific markers for SCs, and showed a high proliferative capacity for long periods. hair follicles, in mice and humans, are important repositories of multipotent stem cells, due to their tendency to differentiate into keratinocytes. human hFSCs, obtained by depilation, preserve their potential for proliferation and prove to be easily accessible. This suggests that the bulge cells may present an alternative source of autologous stem cells for tissue engineering and regenerative medicine.

关键词： Stem Cells hair Follicle Bulge Niche Alopecia

Superparamagnetism of two modern soils from the northeastern Pampean region,Argentina and its paleoclimatic indications

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Superparamagnetism of two modern soils from the northeastern...