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Dynamic Instability of straight Bars subjected to Impulsive Axial Loads Using the DEm

Computer modeling in Engineering & sciences 2015年第2期104卷 87-104页

作者： Leticia Fleck Fadel miguel Leandro Fleck Fadel miguel joao Kaminski Jr. Department of mechanical Engineering UFRGSPorto AlegreRSBrazil Department of Civil Engineering UFSCFlorianopolisSCBrazil Department of structures and Civil Construction UFSMSanta MariaRSBrazil

since the half of the XX century,attention was given to the instability of structures under parametric excitation,especially under periodic *** the other hand,the instability of bars subjected to axial loads of impulsive type has been little studied,in spite of the practical importance of the ***,in Engineering Design it is frequently supposed,without tests or additional verifications,that an axial load of short duration can exceed the Euler critical load of the bar without inducing damage in the *** this context,this paper proposes the use of the truss-like Discrete Element method(DEm)for determining the dynamic response of elastic straight bars subjected to axial loads defined by pulses of short *** proposed approach allows the consideration of initial imperfections,as well as large displacements and other non-linear *** influence of the pulse duration and other effects in the response of the bar are also ***,the performance of the proposed methodology is verified in static and dynamic instability problems of homogeneous bars without geometrical imperfections,by comparing the DEm results with analytical solutions available in the *** that,the DEm is employed to analyze more complex cases,including bars with initial imperfections and non-homogeneous bars,in which material properties,as Young’s modulus and mass density,are assumed to be correlated Gaussian random *** proposed methodology has proven to be a useful and easy tool for analysis of dynamic instability of bars and could therefore be used by designers for estimating the dynamic buckling load.

关键词： Dynamic Instability Critical Buckling Load Discrete Element method Impulsive Load stochastic Fields mesh Imperfections

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Frequency response Optimization of Dual Depletion InGaAs/InP PIN Photodiodes

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Photonic sensors 2016年第1期6卷 63-70页

作者： J. m. Torres PErEIrA joao Paulo N. TOrrEs Instituto de Telecomunicacoes Instituto Superior Tecnico-Universidade de Lisboa Lisboa Portugal

The frequency response of a dual depletion p-i-n （PIN） photodiode structure is investigated. It is assumed that the light is incident on the N side and the drift region is located between the N contact and the absorption region. The numerical model takes into account the transit time and the capacitive effects and is applied to photodiodes with non-uniform illumination and linear electric field profile. With an adequate choice of the device＇s structural parameters, dual depletion photodiodes can have larger bandwidths than the conventional PIN devices.

关键词： PIN photodiodes dual depletion frequency response modeling

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The rediscovery of strix butleri(Hume,1878)in Oman and Iran,with molecular resolution of the identity of strix omanensis robb,van den Berg and Constantine,2013

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Chinese Birds 2016年第2期7卷 85-94页

作者： magnus s.robb George sangster mansour Aliabadian Arnoud B.van den Berg mark Constantine martin Irestedt Ali Khani seyed Babak musavi joao m.G.Nunes maia sarrouf Willson Alyn J.Walsh The sound Approach Department of Bioinformatics and Genetics Swedish Museum of Natural History Department of Zoology Stockholm University Department of Biology Faculty of ScienceFerdowsi University of Mashhad research Department of Zoological Innovations Institute of Applied ZoologyFaculty of ScienceFerdowsi University of Mashhad Khorasan-e razavi Provincial Office of the Department of the Environment Khucheh Gochin Parque Ecológico do Funchal Environment society of Oman Wildfowl reserve

Background:many species of owls(strigidae) represent cryptic species and their taxonomic study is in *** recent years,two new species of owls of the genus strix have been described from the middle East by different research *** has been suggested that one of these species,***,is not a valid species but taxonomic compari?sons have been hampered by the lack of voucher specimens of ***,and the poor state of the holotype of ***:Here we use new DNA sequence data to clarify the taxonomy and nomenclature of the *** *** also report the capture of a single *** sensu stricto in mashhad,***:A cytochrome b sequence of *** was found to be identical to that of the holotype of ***,indicating that the name *** is best regarded as a junior synonym of *** identity of the *** captured in mashhad,Iran,was confirmed using DNA sequence *** represents a major(1300 km) range exten?sion of this ***:The population discovered in Oman in 2013 and originally named ‘***' actually represents the rediscovery of ***,which was known from a single specimen and had not been recorded since *** range of *** extends into northeast *** study augments the body of evidence for the recognition of *** and *** as separate species and highlights the importance of using multiple evidence to study cryptic owl species.

关键词： molecular identification Nomenclature Phylogenetics strigidae strix Taxonomy

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Cytocompatible cellulose nanofibers from invasive plant species Agave americana *** ricinus communis L.:a renewable green source of highly crystalline nanocellulose

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Journal of Zhejiang University-science B(Biomedicine & Biotechnology) 2021年第6期22卷 450-461页

作者： Olga L.EVDOKImOVA Carla s.ALVEs radenka m.KrsmANOVIC WHIFFEN Zaida O.rTEGA Helena TOmás joao r.ODrIGUEs CQm-Centro de Quimica da madeira MMRGUniversidade da MadeiraCampus Universitario da Penteada9020-105 FunchalPortugal Faculty of Polytechnics University of Donja GoricaOktoih 18 WOO PodgoricaMontenegro Departamento de Ingenieria de Procesos Universidad de Las Palmas de Gran Canaria35017 Las Palmas de Gran CanariaLas PalmasSpain school of materials science and Engineering/Center for Nano Energy materials Northwestern Polytechnical UniversityXi'an 710072China

In this study,the fibers of invasive species Agave americana *** ricinus communis *** successfully used for the first time as new sources to produce cytocompatible and highly crystalline cellulose *** nanofibers were obtained by two methods,based on either alkaline or acid *** morphology,chemical composition,and crystallinity of the obtained materials were characterized by scanning electron microscopy(sEm)together with energy-dispersive X-ray spectroscopy(EDX),dynamic light scattering(DLs),X-ray diffraction(XrD),and Fourier transform infrared(FTIr)*** crystallinity indexes(CIs)of the cellulose nanofibers extracted from *** and *** were very high(94.1%and 92.7%,respectively).Biological studies evaluating the cytotoxic effects of the prepared cellulose nanofibers on human embryonic kidney 293 T(HEK293 T)cells were also *** nanofibers obtained using the two different extraction methods were all shown to be cytocompatible in the concentration range assayed(i.e.,0-500μg/mL).Our results showed that the nanocellulose extracted from *** and *** fibers has high potential as a new renewable green source of highly crystalline cellulose-based cytocompatible nanomaterials for biomedical applications.

关键词： Nanofiber Nanocellulose Agave americana L. ricinus communis L. Crystallinity Invasive species Biomedical application

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The hidden half comes into the spotlight: Peeking inside the black box of root developmental phases

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Plant Communications 2022年第1期3卷 36-52页

作者： joao Antonio siqueira Wagner C.Otoni Wagner L.Araujo Departamento de Biologia Vegetal Universidade Federal de Vic¸osaVic¸osaMG 36570-900Brazil

Efficient use of natural resources(e.g.,light,water,and nutrients)can be improved with a tailored developmental program that maximizes the lifetime and fitness of *** plant shoots,a developmental phase represents a time window in which the meristem triggers the development of unique morphological and physiological traits,leading to the emergence of leaves,flowers,and *** developmental phases in plant shoots have been shown to enhance food production in crops,this phenomenon has remained poorly investigated in *** light of recent advances,we suggest that root development occurs in three main phases:root apical meristem appearance,foraging,and *** provide compelling evidence suggesting that these phases are regulated by at least four developmental pathways:autonomous,non-autonomous,hormonal,and *** developmental pathways differentially coordinate organ plasticity,promoting morphological alterations,tissue regeneration,and cell death ***,we suggest how nutritional checkpoints may allow progression through the developmental phases,thus completing the root life *** insights highlight novel and exciting advances in root biology that may help maximize the productivity of crops through more sustainable agriculture and the reduced use of chemical fertilizers.

关键词： developmental transitions plasticity cell fates nutritional checkpoints root development root clock

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static-based early-damage detection using symbolic data analysis and unsupervised learning methods

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Frontiers of structural and Civil Engineering 2015年第1期9卷 1-16页

作者： joao Pedro sANTOs Christian CrEmONA Andre D. OrCEsI Paulo sILVEIrA Luis CALADO Department of structures Av. Brasil 101 Lisbon 1700-066 Portugal Technical Center for Bridge Engineering CEREMA B.P. 214 Provins Cedex 77487 France materials and structures Department IFSTTAR University Paris-Est 14-20 Boulevard Newton Champs sur Marne Marne la Vallee Cedex2 F-77447 France Department of Civil Engineering Technical University Lisbon Avenida Rovisco Pais Lisbon 1096 Portugal

A large amount of researches and studies have been recently performed by applying statistical and machine learning techniques for vibration-based damage detection. However, the global character inherent to the limited number of modal properties issued from operational modal analysis may be not appropriate for early-damage, which has generally a local character. The present paper aims at detecting this type of damage by using static sHm data and by assuming that early-damage produces dead load redistribution. To achieve this objective a data driven strategy is proposed, consisting of the combination of advanced statistical and machine learning methods such as principal component analysis, symbolic data analysis and cluster analysis. From this analysis it was observed that, under the noise levels measured on site, the proposed strategy is able to automatically detect stiffness reduction in stay cables reaching at least 1%.

关键词： structural health monitoring early-damage detection principal component analysis symbolic data symbolic dissimilarity measures cluster analysis numerical model damage simulations

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radiotherapy-customized head immobilization masks:from modeling and analysis to 3D printing

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Nuclear science and Techniques 2019年第9期30卷 103-118页

作者： m.A.r.Loja D.s.Craveiro L.Vieira E.sousa J.A.rodrigues r.J.F.Portal CImOsm Centro de Investigacao em Modelacao e Optimizacao de Sistemas Multifuncionais ISEL IPL Instituto Superior de Engenharia de Lisboa Av. Conselheiro Emidio Navarro 1 1959-007 Lisbon Portugal LAETA IDMEC Instituto Superior Teccnico Universidade de Lisboa Av. Rovisco Pais 1 1049-001 Lisbon Portugal Department of mechanical and Industrial Engineering Faculty of Science and Technology NOVA UNIDEMI Universidade Nova de Lisboa Caparica Portugal H&TrC -Health &Technology research Center ESTeSL - Escola Superior de Tecnologia da Saude de Lisboa Av. D. Joao II Lote 4.69.01 1990-096 Lisbon Portugal Instituto de Biofisica e Engenharia Biomedica Faculdade de Ciencias da Universidade de Lisboa Lisbon Portugal

Immobilization devices may be a valuable aid to ensure the improved effectiveness of radiotherapy treatments where constraining the movements of specific anatomical segments is crucial. This need is also present in other situations, specifically when the superposition of various medical images is required for fine identification and characterization of some pathologies. Because of their structural characteristics, existing head immobilization systems may be claustrophobic and very uncomfortable for patients, during both the modeling and usage stages. Because of this, it is important to minimize all the discomforts related to the mask to alleviate patients’ distress and to simultaneously guarantee and maximize the restraint effectiveness of the mask. In the present work, various head immobilization mask models are proposed based on geometrical information extracted from computerized tomography images and from 3D laser scanning point clouds. These models also consider the corresponding connection to a radiotherapy table, as this connection is easily altered to accommodate various manufacturers’ solutions. A set of materials used in the radiotherapy field is considered to allow the assessment of the stiffness and strength of the masks when submitted to typical loadings.

关键词： Computed tomography 3D laser scanning Geometric modeling Head immobilization devices stiffness and strength analyses 3D printing

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The use of Artificial Neural Networks to estimate seismic damage and derive vulnerability functions for traditional masonry

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Frontiers of structural and Civil Engineering 2020年第3期14卷 609-622页

作者： Tiago miguel FErrEIrA joao EsTEVAO rui mAIO romeu VICENTE IsIsE Institute of Science and Innovation for Bio-Sustainability(IB-S)Department of Civil EngineeringUniversity of MinhoGuimaraes 4800-058Portugal Department of Civil Engineering University of AlgarveFaro 8005-139Portugal rIsCO Department of Civil EngineeringUniversity of AveiroAveiro 3810-193Portugal

ABsTrACT This paper discusses the adoption of Artificial Intelligence-based techniques to estimate seismic damage,not with the goal of replacing existing approaches,but as a mean to improve the precision of empirical *** such,damage data collected in the aftermath of the 1998 Azores earthquake(Portugal)is used to develop a comparative analysis between damage grades obtained resorting to a classic damage formulation and an innovative approach based on Artificial Neural Networks(ANNs).The analysis is carried out on the basis of a vulnerability index computed with a hybrid seismic vulnerability asssment methodology,which is subsequently used as input to both *** results obtained are then compared with real post-earthquake damage observation and critically discussed taking into account the level of adjustment achieved by each ***,a computer routine that uses the ANN as an approximation function is developed and applied to derive a new vulnerability curve *** general terms,the ANN developed in this study allowed to obtain much better approximations than those achieved with the original vulnerability approach,which has revealed to be quite ***,the proposed vulnerability curve expression was found to provide a more accurate damage prediction than the traditional analytical expressions.

关键词： Artificial Neural Networks seismic vulnerability masonry buildings damage estimation,vulnerability curves

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significance of the balance between intracellular glutathione and polyethylene glycol for successful release of small interfering rNA from gold nanoparticles

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Nano research 2015年第10期8卷 3281-3292页

作者： mark mcCully Yulan Hernandez joao Conde Pedro V. Baptista Jesus m. de la Fuente Andrew Hursthouse David stirling Catherine C. Berry CentreforCellEngineering UniversityofGlasgowGlasgowG128QQScotlandUK InstituteofNanoscienceofAragon UniversityofZaragozaZaragoza50018Spain massachusettsInstituteofTechnology InstituteforMedicalEngineeringandScienceHarvard-MITDivisionforHealthSciencesandTechnologyCambridgeMassachusetts02139USA UCIBIO DepartamentodeCienciasdaVidaFaculdadedeCienciaseTecnologiaUniversidadeNovadeLisboaCampusdeCaparicaCaparica2829-516Portugal InstitutodeCienciadematerialesdeAragon(ICmA) CSIC-UniversidaddeZaragozac/PedroCerbuna12Zaragoza50009Spain InstituteofNanoBiomedicineandEngineering KeyLaboratoryforThinFilmandMicrofabricationTechnologyoftheMinistryofEducationResearchInstituteofTranslationMedicineShanghaiJiaoTongUniversityDongchuanRoad800Shanghai200240China schoolofscience UniversityoftheWestofScotlandPaisleyPA12BEScotlandUK

The therapeutic promise of small interfering rNAs （sirNAs） for specific gene silencing is dependent on the successful delivery of functional sirNAs to the cytoplasm. Their conjugation to an established delivery platform, such as gold nanoparticles, offers tremendous potential for treating diseases and advancing our understanding of cellular processes. Their success or failure is dependent on both the uptake of the nanoparticles into the cells and subsequent intracellular release of the functional sirNA. In this study, utilizing gold nanoparticle sirNA-mediated delivery against C-mYC, we aimed to determine if we could achieve knockdown in a cancer cell line with low levels of intracellular glutathione, and determine the influence, if any, of polyethylene glycol （PEG） ligand density on knockdown, with a view to determining the optimal nanoparticle design to achieve C-mYC knockdown. We demonstrate that, regardless of the PEG density, knockdown in cells with relatively low glutathione levels can be achieved, as well as the possible effect of steric hindrance of PEG on the availability of the sirNA for cleavage in the intracellular environment. Gold nanoparticle uptake was demonstrated via transmission electron microscopy and mass spectroscopy, while knockdown was determined at the protein and physiological levels （cells in s-phase） by in-cell westerns and BrdU incorporation, respectively.

关键词： gold nanoparticles PEG glutathione sirNA drug delivery

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molecular characterization of an extensively drug-resistant Acinetobacter baumannii isolated from a corn culture soil

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Pedosphere 2021年第6期31卷 973-976页

作者： joao Pedro rueda FUrLAN Eliana Guedes sTEHLING Departamento de Analises Clinicas Toxicologicas e BromatologicasFaculdade de CienciasFarmaceuticas de Ribeirao PretoUniversidade de Sao Paulo(USP)Ribeirao Preto SP 14040-903(Brazil)

Dear Editor,soil is the most biodiverse habitat on Earth and it has been estimated that one gram of soil can contain up to one billion bacterial cells(Fierer,2017).The microorganisms of soil produce a wide variety of ... 详细信息

关键词： soil corn culture

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