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Atomic-scale simulations of material behaviors and tribology properties for BCC metal film

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Chinese physics B 2016年第1期25卷 412-418页

作者： H D Aristizabal p A parra p lopez E Restrepo-parra pCM Computational Applications Universidad Nacional de Colombia-Sede ManizalesA.A.127ManizalesColombi Universidad Cató1ica de Manizales A.A.357ManizalesColombia

This work has two main purposes：（i） introducing the basic concepts of molecular dynamics analysis to material scientists and engineers, and （ii） providing a better understanding of instrumented indentation measurements, presenting an example of nanoindentation and scratch test simulations. To reach these purposes, three-dimensional molecular dynamics （MD） simulations of nanoindentation and scratch test technique were carried out for generic thin films that present BCC crystalline structures. Structures were oriented in the plane （100） and placed on FCC diamond substrates. A pair wise potential was employed to simulate the interaction between atoms of each layer and a repulsive radial potential was used to represent a spherical tip indenting the sample. Mechanical properties of this generic material were obtained by varying the indentation depth and dissociation energy. The load-unload curves and coefficient of friction were found for each test; on the other hand, dissociation energy was varied showing a better mechanical response for films that present grater dissociation energy. Structural change evolution was observed presenting vacancies and slips as the depth was varied.

关键词： molecular dynamics pair wise potential repulsive radial potential dissociation energy

Bioerosion on Late pleistocene Marine Mollusks:A paleoclimatological and paleoecological Comparison of MIS 7 and MIS 5e with Modern Beaches(Río Negro,Argentina)

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Acta Geologica Sinica(English Edition) 2022年第4期96卷 1181-1198页

作者： Melisa p.CHARO gisela D.CHARÓ Guillermo ACEÑOLAZA Jose L.CAVALLOTTO Instituto Superior de Correlación Geológica(INSUGEO/CONICET-UNT)Miguel Lillo 205 4000 TucumánArgentina Laboratorio de Fluidodinámica Departamento de Ingeniería MecánicaFacultad de IngenieríaUniversidad de Buenos AiresPaseo Colón 850C1063ACVCiudad Autónoma de Buenos AiresArgentina Servicio de Hidrografía Naval Av.Montes de Oca 2124C1270ABW Buenos AiresArgentina

The Late pleistocene littoral ridges of southern South America,especially those of the north of Argentinean patagonia,contain remains of mollusk shells with bioerosion *** sites from marine isotope stages(2 from MIS 7,4 from MIS 5 e)and five sites from modern beaches from northern Río Negro province,with 40 taxa(17 bivalves and 23 gastropods)were analyzed,in the area between west of Baliza San Matías and Las Grutas(41°S).Three ichnogenera were identified in deposits of MIS 7:Entobia,Gastrochaenolites(Domichnia)and Oichnus(praedichnia)with one ichnospecies(***).Six ichnogenera were identified in deposits of MIS 5 e:Entobia,Meandropolydora,pinaceocladichnus,Iramena,Caulostrepsis and Oichnus with one ichnospecies(***).Seven ichnogenera were identified from modern beaches:Entobia,Meandropolydora,Iramena,Caulostrepsis,pinaceocladichnus,Gastrochaenolites(Domichnia)and Oichnus(praedicnia),with two ichnospecies(*** and ***).On this basis,it is inferred that pleistocene benthic communities were constituted from cheilostome bryzoans and polychaete annelids,together with drilling bivalves,predatory gastropods and overall warm-water species of *** these,Chama iudicai was found on plicatula gibbosa from MIS 7 and MIS 5 *** record of warm temperature species suggests a higher sea surface temperature(SST)than the present one and/or the influence of the warm southward Brazilian Current affecting the waters of Golfo San Matí*** the modern beaches surveyed,there is an increase in polychaete annelids,cheilostome bryzoans,temperate-cold species and drilling bivalves,as well as sandy substrate species,which together with an increase of Gastrochaenolites and Caulostrepsis,suggest a colder climate due to the greater influence of the Malvinas Current during the Holocene.

关键词： invertebrate paleontology ichnology Bivalvia Gastropoda polyplacophora bioerosion paleoclimatology paleoecology Quaternary/Holocene Argentina

potential role of the IL-33/ST2 axis in celiac disease

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Cellular & Molecular Immunology 2017年第3期14卷 285-292页

作者： lopez-Casado MA Lorite p palomeque T Torres MI Department of pediatrics Gastroenterology Hospital Virgen de las Nieves Granada Spain Department of Experimental Biology University of Jaen Jaen Spain

The IL-33/ST2 axis has been implicated in the pathogenesis of several tissue-specific autoimmune diseases. Celiac disease （CD） is the only autoimmune disease in which both the major genetic factors （HLA-DQ2/DQ8） and etiologic ones （dietary gluten） for susceptibility are known. We have measured serum levels and determined intestinal tissue expression of IL-33 and its receptor soluble ST2 in patients with CD to investigate their association with disease activity. Serum and tissue levels of both IL-33 and sST2 were significantly higher in patients with CD compared with those in control patients without CD. We show that toxic peptides extracted from barley and wheat gliadin significantly stimulate the production of IL-33 and ST2 in cultured peripheral blood mononuclear cell from celiac patients, strongly implicating the IL-33/ST2 axis in the pathogenesis of CD. The higher levels of IL-33 and its receptor ST2 in tissue and serum reflect an active inflammatory state and may represent a potential biomarker for disease activity. A better understanding of IL-33/ ST2 release, mode of action, and regulation will be crucial to develop therapeutics that target the IL-33/ST2 pathway to treat CD.

关键词： celiac disease gluten peptides IL-33 ST2

Effect of grain recrystallization on stir zone and mechanical property behavior of TRIp 780 steel

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Journal of Iron and Steel Research International 2020年第2期27卷 188-196页

作者： Gladys perez-Medina Hugo lopez Argelia Miranda-perez Eduardo Hurtado-Delgado postgraduate Studies Mexican Corporation in Materials ResearchSaltillo Coahuila 25290Mexico Materials Department University of Wisconsin-MilwaukeeMilwaukeeWI 53201USA

Electron backscatter diffraction(EBSD)and transmission electron microscopy were used to determine the presence of retained austenite and displacive-type phase transformation in the stir zone of friction stir welding(FSW).Severe plastic deformations occurred in the stir zone where there was an increase in the temperature attributed to the FSW process and subsequently a grain *** the recrystallization phenomena,the formation of grain evolution development in steels was resolved using *** addition,a tensile test was carried out in order to reveal the results of mechanical *** was found that the fracture zone occurred in the stir zone with an ultimate tensile strength of 587 Mpa,a decrease of 267 Mpa compared with that of the base *** this result,it is evident that the fracture exhibits numerous elongated dimples,distributed homogeneously,and certain locations contain cleavage fractures due to differences in the microstructure of the base *** profile tests of the welding regions were conducted,and the results showed that the stir zone was present with elevated hardness(near 350 HV).Characterization techniques revealed that the austenite-to-martensite transformation occurred in the stir zone,resulting in a loss of mechanical properties in the joint.

关键词： Friction welding Transformation-induced plasticity steel Stir zone Mechanical property Tensile test

Intervention to increase physical activity in irritable bowel syndrome shows long-term positive effects

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World Journal of Gastroenterology 2015年第2期21卷 600-608页

作者： Elisabet Johannesson gisela Ringstrom Hasse Abrahamsson Riadh Sadik Department of Internal Medicine Institute of MedicineSahlgrenska AcademyUniversity of Gothenburg41345 GoteborgSweden Narhalsan Sorhaga Rehabilitation Unit44183 AlingsasSweden

AIM: To assess the long-term effects of physical activity on irritable bowel syndrome(IBS) symptoms and on quality of life, fatigue, depression and ***: Seventy-six patients from a previous randomized controlled interventional study on increased physical activity in IBS were asked to participate in this long-term follow-up study. The included patients attended one visit in which they filled out questionnaires and they underwent a submaximal cycle ergometer test. The primary end point was the change in the IBS Severity Scoring System(IBS-SSS) at baseline, i.e., before the intervention and at follow-up. The secondary endpoints were changes in quality of life, fatigue, depression and ***: A total of 39 [32 women, median age 45(28-61) years] patients were included in this followup. Median follow-up time was 5.2(range: 3.8-6.2) years. The IBS symptoms were improved compared with baseline [IBS-SSS: 276(169-360) vs 218(82-328), p = 0.001]. This was also true for the majority of the dimensions of psychological symptoms such as disease specific quality of life, fatigue, depression and anxiety. The reported time of physical activity during the week before the visit had increased from 3.2(0.0-10.0) h at baseline to 5.2(0.0-15.0) h at follow-up, p = 0.019. The most common activities reported were walking, aerobics and cycling. There was no significant difference in the oxygen uptake 31.8(19.7-45.8) m L per min per kg at baseline vs 34.6(19.0-54.6) m L/min per kg at ***: An intervention to increase physical activity has positive long-term effects on IBS symptoms and psychological symptoms.

关键词： Gastrointestinal diseases Irritable bowel syndrome Exercise Follow-up physical activity

Leishmaniasis in the Argentine Republic: Temporal and geographical distribution from 2013 to 2017

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Asian pacific Journal of Tropical Medicine 2019年第7期12卷 300-305页

作者： GermanóMaría J Salomón María C Neira gisela Lozano Esteban Mackern-Oberti Juan p Cargnelutti Diego E Consejo Nacional de Investigaciones Científicas y Técnicas Centro Científico y Tecnológico de MendozaInstituto de Medicina y Biología Experimental de CuyoMendozaArgentina Universidad Nacional de Cuyo Facultad de Ciencias Médicasárea de ParasitologíaMendozaArgentina Universidad Juan Agustín Maza Facultad de Ciencias Veterinarias y AmbientalesCentro de Investigación en Parasitología RegionalMendozaArgentina Universidad Nacional de Cuyo Facultad de Ciencias MédicasInstituto de FisiologíaMendozaArgentina

Objective: To assess the temporal and geographical distribution of confirmed cases of cutaneous, mucocutaneous and visceral leishmaniasis in the Argentine Republic from 2013 to 2017. Methods: A retrospective study was carried out using data collected from the Integrated Surveillance Bulletin database of the National System of Health Surveillance. Confirmed cases of cutaneous, mucocutaneous and visceral leishmaniasis up to the 52 nd epidemiological week of each year was included. Results: In the 5 years period, 1 295 confirmed leishmaniasis cases were reported in the Argentine Republic. One thousand twenty-eight(1 028) cases corresponded to cutaneous leishmaniasis(87.10%), being the most common type of leishmaniasis. Mucocutaneous leishmaniasis was in the second place in the country with 115 cases reported, mostly in the Northwest and Northeast regions. A total of 52 individuals with visceral leishmaniasis were identified and Misiones province was the most affected. Conclusions: It is important to analyze the temporal and geographical distribution of leishmaniasis in order to provide an adequate management and surveillance.

关键词： Leishmaniasis Epidemiology Argentine Republic Temporal distribution Geographical distribution

Individual repeatability in timing and spatial flexibility of migration routes of trans-Saharan migratory raptors

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Current Zoology 2014年第5期60卷 642-652页

作者： pascual lopez-lopez Clara GARCLA-RIpOLLES Vicente URIOS Vertebrates Zoology Research Group CIBIO Research Institute University ofAlicante Edificio Ciencias III Apdo. 99 E-03080Alicante Spain

Satellite-tracking technology has allowed scientists to make a quantum leap in the field of migration ecology. Nowadays, the basic description of migratory routes of many species of birds has been reported. However, the investigation of bird migration at individual level （i.e. repeatability in migratory routes and timing） still remains seldom explored. Here, we investigated repeated migratory trips of a trans-Saharan endangered migratory raptor, the Egyptian Vulture Neophron percnopterus, tracked by GpS satellite telemetry. We compared between- and within-individual variation in migratory routes and timing in order to assess the degree of repeatability （or conversely, the flexibility） in migration. To this end, we analysed a dataset of 48 trips （23 springs and 25 autumns） recorded for six adult birds during 2007-2013. Our results showed consistent migration timing at the individual level, both in spring and autumn. Interestingly, there was a high degree of flexibility in the routes followed by the same individual in different years, probably due to variations in meteorological conditions. Contrary to expectations of a faster migration in spring than in autumn owing to a time-minimization strategy for breeding, birds spent less time in autumn migration （13 ± 2 days, range = 9-18 d） than in spring migration （19 ± 3 days, range = 13-26 d）, which can be explained by differences in environmental con- ditions en route. Egyptian vultures showed a consistent clockwise loop migration through western Africa, following more easterly routes in autumn than in spring. Finally, our results provide supporting evidence of low phenotypic plasticity in timing of migration （i.e. strong endogenous control of migration） and high flexibility in routes [Current Zoology 60 （5）： 642-652, 2014].

关键词： Egyptian vulture Endogenous control GpS Loop migration Neophron percnopterus Random routes Satellite tracking Simulation

An unsupervised pattern recognition methodology based on factor analysis and a genetic-DBSCAN algorithm to infer operational conditions from strain measurements in structural applications

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Chinese Journal of Aeronautics 2021年第2期34卷 165-181页

作者： Juan Carlos pERAFAN-lopez Julian SIERRA-pEREZ Grupo de Investigacion en Ingenieria Aeroespacial Universidad Pontificia BolivarianaCircular 170-01Medellin 050031Colombia

Structural Health Monitoring(SHM) suggests the use of machine learning algorithms with the aim of understanding specific behaviors in a structural system. This work introduces a pattern recognition methodology for operational condition clustering in a structure sample using the well known Density Based Spatial Clustering of Applications with Noise(DBSCAN) *** methodology was validated using a data set from an experiment with 32 Fiber Bragg Gratings bonded to an aluminum beam placed in cantilever and submitted to cyclic bending loads under 13 different operational conditions(pitch angles). Further, the computational cost and precision of the machine learning pipeline called FA + GA-DBSCAN(which employs a combination of machine learning techniques including factor analysis for dimensionality reduction and a genetic algorithm for the automatic selection of initial parameters of DBSCAN) was measured. The obtained results have shown a good performance, detecting 12 of 13 operational conditions, with an overall precision over 90%.

关键词： Clustering DBSCAN Factor analysis FBGs pattern recognition Strain field

Tri-axial accelerometry shows differences in energy expenditure and parental effort throughout the breeding season in long-lived raptors

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Current Zoology 2022年第1期68卷 57-67页

作者： pascual lopez-lopez Arturo MpERONA Olga EGEA-CASAS Jon MORANT Vicente URIOS Movement Ecology Laboratory Cavanilles Institute of Biodiversity and Evolutionary BiologyUniversity of Valencia.C/Catedratico JoseBeltran 2E-46980 PaternaValenciaSpain Department of Ornithology Aranzadi Sciences SocietyDonostia-S.SebastianGuipuzcoa 03690Spain Vertebrates Zoology Research Group University of AlicanteApdo.99Alicante E-03080Spain

Cutting-edge technologies are extremely useful to develop new workflows in studying ecological data,particularly to understand animal behavior and movement trajectories at the individual *** parental care is a well-studied phenomenon,most studies have been focused on direct observational or video recording data,as well as experimental ***,what happens out of our sight still remains *** high-frequency GpS/GSM dataloggers and tri-axial accelerometers we monitored 25 Bonelli’s eagles Aquila fasciata during the breeding season to understand parental activities from a broader *** used recursive data,measured as number of visits and residence time,to reveal nest attendance patterns of biparental care with role specialization between *** data interpreted as the overall dynamic body acceleration,a proxy of energy expenditure,showed strong differences in parental effort throughout the breeding season and between ***,males increased substantially their energetic requirements,due to the increased workload,while females spent most of the time on the ***,during critical phases of the breeding season,a low percentage of suitable hunting spots in eagles’territories led them to increase their ranging behavior in order to find food,with important consequences in energy consumption and mortality *** results highlight the crucial role of males in raptor species exhibiting biparental ***,we exemplify how biologging technologies are an adequate and objective method to study parental care in raptors as well as to get deeper insight into breeding ecology of birds in general.

关键词： biologging GpS movement ecology ODBA space use telemetry