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Automatic Detection of COVID-19 Infection Using Chest X-Ray Images Through Transfer Learning

IEEE/CAA Journal of Automatica Sinica 2021年第1期8卷 239-248页

作者： Elene Firmeza Ohata Gabriel Maia Bezerra João Victor Souza das Chagas Aloísio Vieira Lira Neto Adriano Bessa Albuquerque Victor Hugo Cde Albuquerque Pedro Pedrosa Rebouças Filho the universidade federal do ceará FortalezaCE 60455-970and also with the Instituto Federal do CearáFortalezaCE 60040-215Brazil the Instituto federal do ceará FortalezaCE 60040-215Brazil the universidade de Fortaleza FortalezaCE 60811-905Brazil

The new coronavirus(COVID-19),declared by the World Health Organization as a pandemic,has infected more than 1 million people and killed more than 50 *** infection caused by COVID-19 can develop into pneumonia,which can be detected by a chest X-ray exam and should be treated *** this work,we propose an automatic detection method for COVID-19 infection based on chest X-ray *** datasets constructed for this study are composed of194 X-ray images of patients diagnosed with coronavirus and 194 X-ray images of healthy *** few images of patients with COVID-19 are publicly available,we apply the concept of transfer learning for this *** use different architectures of convolutional neural networks(CNNs)trained on Image Net,and adapt them to behave as feature extractors for the X-ray ***,the CNNs are combined with consolidated machine learning methods,such as k-Nearest Neighbor,Bayes,Random Forest,multilayer perceptron(MLP),and support vector machine(SVM).The results show that,for one of the datasets,the extractor-classifier pair with the best performance is the Mobile Net architecture with the SVM classifier using a linear kernel,which achieves an accuracy and an F1-score of 98.5%.For the other dataset,the best pair is Dense Net201 with MLP,achieving an accuracy and an F1-score of 95.6%.Thus,the proposed approach demonstrates efficiency in detecting COVID-19 in X-ray images.

关键词： Convolutional neural networks(CNNs) COVID-19 transfer learning X-ray

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Effect of operating conditions and potassium content on Fischer-Tropsch liquid products produced by potassium-promoted iron catalysts

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Journal of Natural Gas Chemistry 2008年第2期17卷 175-178页

作者： Francisco E.M.Farias Fernando G.Sales Fabiano A.N.Fernandes universidade federal do ceará Departamento de Engenharia QuímicaCampus do PiciBloco 70960455-760 Fortaleza-CEBrazil

The dependencies of Fischer-Tropsch synthesis liquid hydrocarbon product distribution on operating pressure and temperature have been studied over three potassium-promoted iron catalysts with increasing potassium molar content. The study followed an experimental planning and the results were analyzed based on surface response methodology. The effects of different operating conditions and potassium contents on the liquid product distribution were compared based on number average carbon number and dispersion. Results showed that high pressures （25 to 30 arm） favored the production of waxes that could be converted into liquid fuels through hydrocracking, while greater direct selectivity towards diesel was favored by low pressure （20 arm） using catalysts with low potassium to iron molar ratios. The liquid product distribution produced using an iron catalyst with high potassium content presented higher number-average number of carbons when compared to the distribution obtained using an iron catalyst with low potassium content.

关键词： Fischer-Tropsch synthesis liquid fuels iron-based catalyst potassium

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The Influence of High Temperature Exposure on the Wear Performance of a Ni Based Alloy PTA Coating

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材料热处理学报 2004年第5期25卷 152-156页

作者： Karin Graf Ana Sofia C.M. d'OIiveira Mechanical Department of universidade federal do Parana Curitiba BrazilMechanical Department of Universidade Federal do Parana Curitiba Brazil

Degradation phenomena like wear and corrosion, may have their effects accelerated as components operate at high temperature. The aim of this work is to make an indirect evaluation of the influence of high temperature exposure on wear behavior of Ni coatings. A Ni-Cr-Mo-W alloy, was deposited with Plasma Transferred Arc (PTA) process. An indirect approach based on the Ahrrenius relationship was used to evaluated long time exposures at high temperatures. To simulate longer exposures at lower temperatures, coatings were exposed to higher temperatures for the same time interval. So coatings were soaked in an air furnace at 650°C, 1000°C and 1200°C. Metal/metal wear behavior was evaluated by pin-on-disc tests. Pins were removed from the coatings by eletrodischarge machining and rubbed against a VC31 quenched and tempered tool steel. Two sets of wear tests were run at 2m/s, for different loads (0.5, 1.0, 2.0 and 3.0Kg) and for different sliding distances (120, 720, 1080, 1440 and 1800m).Coatings characterization was done by scanning electronic microscopy and Vickers microhardness. Results showed as temperature is increased, coatings wear performance is altered, and this is associated with microstructural changes.

关键词：磨损 Ni合金 PTA 高温曝露

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Pathogenesis and clinical management of arboviral diseases

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World Journal of Virology 2025年第1期14卷 9-50页

作者： Victoria Cenci Dietrich Juan Marcos Caram Costa Marina Maria Gomes Leite Oliveira Carlos Eduardo Oliveira Aguiar Luis Guilherme de Oliveira Silva Marcel Silva Luz Fabian Fellipe Bueno Lemos Fabrício Freire de Melo Instituto Multidisciplinar em Saúde Universidade Federal da BahiaVitória da Conquista 45029-094BahiaBrazil

Arboviral diseases are viral infections transmitted to humans through the bites of arthropods,such as mosquitoes,often causing a variety of pathologies associated with high levels of morbidity and *** the past decades,these infections have proven to be a significant challenge to health systems worldwide,particularly following the considerable geographic expansion of the dengue virus(DENV)and its most recent outbreak in Latin America as well as the difficult-tocontrol outbreaks of yellow fever virus(YFV),chikungunya virus(CHIKV),and Zika virus(ZIKV),leaving behind a substantial portion of the population with complications related to these ***,the world is experiencing a period of intense globalization,which,combined with global warming,directly contributes to wider dissemination of arbovirus vectors across the ***,all continents remain on high alert for potential new ***,this review aims to provide a comprehensive understanding of the pathogenesis of the four main arboviruses today(DENV,ZIKV,YFV,and CHIKV)discussing their viral characteristics,immune responses,and mechanisms of viral evasion,as well as important clinical aspects for patient *** includes associated symptoms,laboratory tests,treatments,existing or developing vaccines and the main associated complications,thus integrating a broad historical,scientific and clinical approach.

关键词： Arboviruses Arbovirus infections Dengue Zika virus Yellow fever Chikungunya virus Clinical diagnosis Pathogenesis Flavivirus Togaviridae infections

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Raman Spectra of Nd:La3Ga5SiO14 and Nd:La3Ga5.5Ta0.5O14 Crystals

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Chinese Journal of Structural Chemistry 2016年第11期35卷 1673-1678页

作者：张娜娜王继扬潘晓茹宋明君 Clenilton Costa dos Santos Ilde Guedes da Guedesa College of Chemistry & Chemical and Environmental Engineering Weifang University State Key Laboratory of Crystal Materials Shandong University Departamento de Física CCETUniversidade Federal do Maranh?o Departamento de Física Universidade Federal do CearáCampus do Pici

Single crystals of Nd：La3Ga5SiO14 （NLGS） and Nd：La3Ga5.5Ta0.5O14 （NLGT） were grown by Czochralski method. Both crystals exhibit a langasite structure （space group D32 （P321） with Z = 1）, whose general formula is A3BC2D3O14, where A, B, C and D represent the dodecahedral, octahedral and tetrahedral positions, respectively. The adding of low content of Nd does not change the crystal structure. Although they are isostructural, the distribution of atoms among the symmetric sites is different. While NLGT exhibits a perfect orderly structure, NLGS exhibits an intrinsically disordered structure due to the random distribution of Ga and Si atoms at the C3（2） symmetry sites. To understand what changes occur in the phonon distribution when Ta replaces Si, we recorded and analyzed room temperature polarized Raman spectra. We observe 8A1＋18E modes for NLGS and 10A1＋13E for NLGT crystals. When Si is substituted by Ta, we observe that the wavenumber of some modes related to vibrations involving Ga and O atoms decreases. This agrees with the fact that the Ga–O bonds are shorter in NLGS than in NLGT.

关键词： Czochralski method langasite structure Raman scattering piezoelectric

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Bioactive extracts of red seaweeds Pterocladiella capillacea and Osmundaria obtusiloba(Floridophyceae:Rhodophyta) with antioxidant and bacterial agglutination potential

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Asian Pacific Journal of Tropical Medicine 2016年第4期9卷 363-370页

作者： Daniel Barroso de Alencar Fátima Cristiane Teles de Carvalho Rosa Helena Rebouas Daniel Rodrigues dos Santos Kelma Maria dos Santos Pires-Cavalcante Rebeca Larangeira de Lima Bárbara Mendes Baracho Rayssa Mendes Bezerra Francisco Arnaldo Viana Regine Helena Silva dos Fernandes Vieira Alexandre Holanda Sampaio Oscarina Viana de Sousa Silvana Saker-Sampaio Laboratrio de Produtos Naturais Marinhos.Departamento de Engenharia de Pesca Universidade Federal do Ceará.Campus do Pici.Ar.Mister Hull.s/nCaixa Postal 6043 Laboratrio de Microbiologia Ambiental e do Pescado.Instituto de Ciências do Mar.universidade federal do ceará.Av.da Abolicao 3207 Laboratrio de Microbiologia Ambiental e do Pescado.Instituto de Ciências do Mar.universidade federal do ceará Laboratrio de Produtos Naturais Marinhos.Departamento de Engenharia de Pesca Universidade Federal do Ceará Laboratrio de Cromatografia Departamento de QuimicaUniversidade do Estado do Rio Grande do NorteCampus Universitário Central

Objective:To evaluate the antioxidant,antibacterial and bacterial cell agglutination activities of the hexane(Hex) and 70%ethanol(70%EtOH) extracts of two species of red seaweeds Pterocladiella capillacea(***) and Osmundaria ***:In vitro antioxidant activity was determined by DPPH radical scavenging assay,ferric-reducing antioxidant power assay,ferrous ion chelating assay,β-carotene bleaching assay and total phenolic content *** activity was tested using the method of disc diffusion on Mueller-Hinton *** ability of algal extracts to agglutinate bacterial cells was also ***:The 70%EtOH extract of the two algae showed the highest values of total phenolic content compared to the Hex *** results of DPPH for both extracts(Hex,70%EtOH) of Osmundaria obtusiloba(43.46%and 99.47%) were higher than those of ***(33.04%and 40.81%) at a concentration of 1 000 μg/*** for the ferrous ion chelating,there was an opposite behavior,extracts of *** had a higher *** extracts showed a low ferric-reducing antioxidant power,with optical density ranging from0.054 to *** activities of all extracts evaluated for β-carotene bleaching were above 40%.There was no antibacterial activity against bacterial strains ***,the extracts of both species were able to agglutinate bacterial Gram positive cells of Staphylococcus aureus and Gram negative cells of Escherichia coli,multidrug-resistant Salmonella and Vibrio *** This is the first report of the interaction between these algal extracts,rich in natural compounds with antioxidant potential,and Gram positive and Gram negative bacterial cells.

关键词： Bioactive compounds Antioxidant Bacterial agglutination Rhodophyta

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Fern extracts potentiate fluconazole activity and inhibit morphological changes in Candida species

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Asian Pacific Journal of Tropical Biomedicine 2017年第11期7卷 1025-1030页

作者： Maria A.Freitas Antonia T.L.Santos Antonio J.T.Machado Ana Raquel P.Silva Fábia F.Campina Maria S.Costa Gioconda M.A.B.Martins Maria Flaviana B.Morais-Braga Saulo R.Tintino Irwin R.A.Menezes Jaime Ribeiro-Filho Altevir P.Medeiros Adeliana S.Oliveira Patrício B.Maracajá Henrique D.M.Coutinho universidade Regional do Cariri-URCA universidade federal Rural do Semi-A′rido-UFERSA universidade federal do Rio Grande do Norte-UFRN universidade federal de Campina Grande-UFCG

Objective: To investigate the antifungal activity of the fern species Lygodium venustum(L. venustum) and Pityrogramma calomelanos(P. calomelanos) against Candida albicans and Candida tropicalis ***: The microdilution method was used to evaluate the antifungal activity, as well as the modulating effects of ethanolic extracts of these plants in combination with fluconazole. The minimum inhibitory concentration(MIC), minimum fungicide concentration and morphological changes were also ***: The extract obtained from L. venustum presented a MIC > 8 192 mg/m L, while the extract obtained from and P. calomelanos presented a MIC = 8 192 mg/m L, indicating that they present weak antifungal activity. However, combination of the extracts with Fluconazole potentiated the antifungal activity of this drug. At different experimental conditions, such as concentration of the extract and type of strain, the extracts inhibited hyphae and pseudohyphae formation, indicating that these fern species can affect the morphology of the ***: The extracts obtained from the fern species L. venustum and P. calomelanos dose not present significant antifungal activity. However, P. calomelanos potentiates the activity of fluconazole and both extracts inhibits the morphological changes in Candida species, indicating that they have potential pharmacological activity as modulators of fungal biology. Therefore, novel studies are required to characterize the interference of these extracts in the virulence and pathogenicity of Candida species as well as the potential of fern species to treat fungal infections.

关键词： Dimorphism Candida species Ferns Lygodium venustum Pityrogramma calomelanos

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Null Controllability of Some Reaction-Diffusion Systems with Only One Control Force in Moving domains

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Chinese Annals of Mathematics,Series B 2016年第1期37卷 29-52页

作者： J. LIMACO M. CLARK A. MARINHO S. B. de MENEZES A. T. LOUREdo universidade federal Fluminense IM RJ Brazil universidade federal do Piaui DM PI Brazil universidade federal do Piaui DM PI Brazil universidade federal do ceara DM CE Brazil universidade Estadual da Pavaiba DM PB Brazil.

In this article, the authors establish the local null controllability property for semilinear parabolic systems in a domain whose boundary moves in time by a single control force acting on a prescribed subdomain. The proof is based on Kakutani＇s fixed point theorem combined with observability estimates for the associated lineaxized system.

关键词： Kakutani's fixed point theorem Unique continuation Null controllability

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PREDICTION OF VORTEX-INDUCED VIBRATION OF LONG FLEXIBLE CYLINDERS MODELED BY A COUPLED NONLINEAR OSCILLATOR:INTEGRAL TRANSFORM SOLUTION

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Journal of Hydrodynamics 2012年第6期24卷 888-898页

作者： GU Ji-jun AN Chen LEVI Carlos SU Jian Ocean Engineering Program COPPEUniversidade Federal do Rio de Janeiro Nuclear Engineering Program COPPEUniversidade Federal do Rio de Janeiro

The Generalized Integral Transform Technique （GITT） was applied to predict dynamic response of Vortex-Induced Vibration （VIV） of a long flexible cylinder. A nonlinear wake oscillator model was used to represent the cross-flow force acting on the cylinder, leading to a coupled system of second-order Partial Differential Equations （PDEs） in temporal variable. The GITT approach was used to transform the system of PDEs to a system of Ordinary Differential Equations （ODEs）, which was numerically solved by using the Adams-Moulton and Gear method （DIVPAG） developed by the International Mathematics and Statistics Library （IMSL）. Numerical results were presented for comparison to those given by the finite difference method and experimental results, allowing a critical evaluation of the technique performance. The influence of variation of mean axial tension induced by elongation of flexible cylinder was evaluated, which was shown to be not negligible in numerical simulation of VIV of a long flexible cylinder.

关键词： Vortex-Induced Vibration (VIV) nonlinear wake oscillator flexible cylinder integral transform

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Mitochondrial GPX1 silencing triggers differential photosynthesis impairment in response to salinity in rice plants

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Journal of Integrative Plant Biology 2016年第8期58卷 737-748页

作者： Yugo Lima-Melo Fabricio E.L.Carvalho Márcio O.Martins Gisele Passaia Rachel H.V.Sousa Milton C.Lima Neto Márcia Margis-Pinheiro Joaquim A.G.Silveira Department of Biochemistry and Molecular Biology Federal University of Ceará Department of Genetics Federal University of Rio Grande do Sul

The physiological role of plant mitochondrial glutathione peroxidases is scarcely known. This study attempted to elucidate the role of a rice mitochondrial isoform（GPX1） in photosynthesis under normal growth and salinity conditions. GPX1 knockdown rice lines（GPX1s） were tested in absence and presence of 100 mM NaCl for 6 *** reduction of GPX1 s line under non-stressful conditions, compared with non-transformed（NT） plants occurred in parallel to increased H_2O_2 and decreased GSH contents. These changes occurred concurrently with photosynthesis impairment, particularly in Calvin cycle＇s reactions, since photochemical efficiency did not ***, GPX1 silencing and downstream molecular/metabolic changes modulated photosynthesis differentially. In contrast, salinity induced reduction in both phases of photosynthesis, which were more impaired in silenced *** changes were associated with root morphology alterations but not shoot growth. Both studied lines displayed increased GPX activity but H_2O_2 content did not change in response to salinity. Transformed plants exhibited lower photorespiration, water use efficiency and root growth, indicating that GPX1 could be important to salt tolerance. Growth reduction of GPX1 s line might be related to photosynthesis impairment, which in turn could have involved a cross talk mechanism between mitochondria and chloroplast originated from redox changes due to GPX1 deficiency.

关键词： CO2 assimilation glutathione peroxidase Oryza sativa photochemistry redox homeostasis

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