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Development and assessment of a multifunctional chitosan-based coating applied on AZ31 magnesium alloy: Corrosion resistance and antibacterial performance against Klebsiella Pneumoniae

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Journal of Magnesium and Alloys 2021年第6期9卷 2133-2144页

作者： Emmanuel Mena-Morcillo Lucien Veleva Mariana Cerda-Zorrilla Montserrat Soria-castro Juan C.castro-Alcátara Rosa C.Canul-Puc Applied Physics Department Center for Research and Advanced Study(CINVESTAV-IPN)Carr.Ant.a Progreso Km.697310MeridaYucatanMexico Marine Resources Department Center for Research and Advanced Study(CINVESTAV-IPN)Carr.Ant.a Progreso Km.697310MeridaYucatanMexico

This work presents a simple method to functionalise the surface of AZ31 magnesium alloy by applying a duplex MgF_(2)/chitosan coating,which improves its corrosion resistance and provides it with some antibacterial ***,the effect of three chitosan solutions with different concentrations on the growth of the bacteria Klebsiella pneumoniae in nutritive medium(TSB)was evaluated by absorbance kinetics experiments,where the chitosan solution at 2%(m/V)was selected for the coating *** coating application,the AZ31 substrate was pretreated with hydrofluoric acid for 48 hours in order to form a MgF_(2)conversion ***,the coating was applied to the pretreated substrate through the dry-casting *** of the alloy in each surface condition(bare,pretreated,and pretreated+coated with chitosan)were exposed to simulated body fluid(SBF)for 21 days at 37°C,with the solution renewed every 24 hours and the wastes *** surfaces were characterised by SEM-EDS,and XPS after the immersion tests,whereas the stored solutions were employed to measure the change in the Mg-ions *** impedance spectroscopy and potentiodynamic polarisation were performed in each surface condition to compare their corrosion resistance in *** antibacterial activity of the functionalised surfaces was evaluated by the plate counting method and compared with bare *** results were correlated and demonstrate that the modified surface of AZ31 achieved a higher corrosion resistance when it was exposed to SBF,as well as a reduction of the bacterial growth during in vitro tests.

关键词： AZ31 Chitosan coating Simulated body fluid Corrosion Antibacterial activity

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Enhanced Rsa (Ersa): An Advanced Mechanism for Improving the Security

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Intelligent Automation & Soft Computing 2023年第5期36卷 2267-2279页

作者： S.castro R.PushpaLakshmi Karpagam College of Engineering Coimbatore641032Tamil NaduIndia PSNA College of Engineering And Technology Dindigul624622Tamil NaduIndia

Cloud computing has become ubiquitous in our daily lives in recent *** are the source of technology that is generated hugely by various *** data is dealing with huge data volumes or complex *** major concern in big data is security *** concerns create a negative impact on the user on the aspect of *** big data still,security threats exist as com-monly known as DDOS(Distributed-Denial-of-Service)attacks,data loss,Inade-quate Data Backups,System Vulnerabilities,and Phishing as well as Social Engineering *** our work,we have taken the data loss and Inadequate Data Backups issues into *** analyze that RSA(Rivest,Shamir,&Adleman)is the most secure cryptography *** cloud computing,user authentication is the weaker section to be ***,the cryptogra-phy mechanism is done in the authentication section *** implemented our new idea of registration with selected images and pins for processing *** valid authentication approval earned by the proposed mechanism,the user is allowed to use the cloud database,encryption,decryption,*** prove the efﬁ-ciency level of our proposed system,a comparison work is conducted between DSSE(Digital Signature Standard Encryption)and EFSSA(Efﬁcient framework for securely sharing aﬁle using asymmetric key distribution management).The experimental work is carried out and the performance evaluation is done using encryption time and decryption time analysis,throughput,and processing *** this observation,the security level attained by ERSA is far better in compar-ison to DSSE and EFSSA with the maximum throughput attained by the proposed E-RSA being 500 Mb/Min and encryption time of 3.2 s,thus ensuring the user trust in using the cloud environment.

关键词： Cloud computing encryption decryption ﬁle sharing RSA key generation

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领导者–跟随者Thomson跳环系统的自抗扰控制设计(英文)

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控制理论与应用 2013年第12期30卷 1564-1572页

作者： mario RAMIREZ-NERIA José L GARCIA-ANTONIO Hebertt J SIRA-RAMIREZ Martin VELASCO-VILLA Rafael castro-LINARES Depto. de Control Automatico Cinvestav Av. IPN 2508 C.E 07360 Mexico D.F. Seccion de Mecatronica Depto. de Ingenieria Electrica Cinvestav Av. IPN 2508 C.E 07360 Mexico D.E

将用电磁方法悬浮起来的一对环构成领导者–跟随者系统实现对光滑参考轨线的跟踪要求.这一任务通过设计具有对扰动进行在线估计与补偿功能的自抗扰控制器(ADRC)实现.本文设计方法与传统ADRC的主要不同在于领导者和跟随者的跟踪控制器设... 详细信息

将用电磁方法悬浮起来的一对环构成领导者–跟随者系统实现对光滑参考轨线的跟踪要求.这一任务通过设计具有对扰动进行在线估计与补偿功能的自抗扰控制器(ADRC)实现.本文设计方法与传统ADRC的主要不同在于领导者和跟随者的跟踪控制器设计都是基于平坦输出的线性化近似系统.超出线性化近似有效区域的大的高度偏差所导致的未知非线性则被视为扰动,这个扰动借助于线性扩张观测器进行在线估计并通过线性反馈控制器进行消除.实验结果检验了本文所提方法的有效性.

关键词： Thomson跳环自抗扰控制广义比例积分(GPI)观测器领导者-跟随者布局

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Calderón–Zygmund Operators in the Bessel Setting for All Possible Type Indices

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Acta Mathematica Sinica,English Series 2014年第4期30卷 637-648页

作者： Alejandro J.castro Tomasz Z.SZAREK Departamento de Análisis Matemático Universidad de La LagunaCampus de AnchietaAvda.Astrofísico Francisco Sánchezs/n38271 La Laguna (Sta.Cruz de Tenerife)Spain Instytut Matematyczny Polska Akademia NaukSniadeckich 800–956 WarszawaPoland

We show that many harmonic analysis operators in the Bessel setting, including maximal operators, Littlewood-PMey-Stein type square functions, multipliers of Laplace or Laplace-Stieltjes transform type and Riesz transforms are, or can be viewed as, CalderSn-Zygmund operators for all possible values of type parameter λ, in this context. This extends results existing in the literature, but being justified only for a restricted range of λ.

关键词： Bessel operator Bessel semigroup maximal operator square function multiplier Riesztransform Calder6n-Zygmund operator

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Coronavirus disease-2019 and the intestinal tract:An overview

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World Journal of Gastroenterology 2021年第13期27卷 1255-1266页

作者： Gabriela Gama Freire Alberca Rosa Liliana Solis-castro Maria Edith Solis-castro Ricardo Wesley Alberca Department of Microbiology Institute of Biomedical Sciences-University of São PauloSão Paulo 05508-000Brazil Departamento Académico de Biología Bioquímica Facultad de Ciencias de la SaludUniversidad Nacional de TumbesPampa Grande 24000TumbesPeru Departamento Académico de Medicina Humana Facultad de Ciencias de la SaludUniversidad Nacional de TumbesPampa Grande 24000TumbesPeru Laboratorio de Dermatologia e Imunodeficiencias(LIM-56) Departamento de DermatologiaFaculdade de Medicina FMUSPUniversidade de São PauloSão Paulo 01246-903Brazil

Severe acute respiratory syndrome coronavirus-2(SARS-CoV-2) infection can progress to a severe respiratory and systemic disease named coronavirus disease–2019(COVID-19). The most common symptoms are fever and respiratory discomfort. Nevertheless, gastrointestinal infections have been reported, with symptoms such as diarrhea, nausea, vomiting, abdominal pain, and lack of appetite. Importantly, SARS-CoV-2 can remain positive in fecal samples after nasopharyngeal clearance. After gastrointestinal SARS-CoV-2 infection and other viral gastrointestinal infections, some patients may develop alterations in the gastrointestinal microbiota. In addition, some COVID-19 patients may receive antibiotics, which may also disturb gastrointestinal homeostasis. In summary, the gastrointestinal system, gut microbiome, and gut-lung axis may represent an important role in the development, severity, and treatment of COVID-19. Therefore, in this review, we explore the current pieces of evidence of COVID-19 gastrointestinal manifestations, possible implications, and interventions.

关键词： COVID-19 SARS-CoV-2 Gastrointestinal Microbiota Antibiotics

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The potential leaching and mobilization of trace elements from FGD-gypsum of a coal-fired power plant under water re-circulation conditions

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Journal of Environmental Sciences 2015年第6期27卷 72-80页

作者： Patricia Córdoba Iria castro Mercedes Maroto-Valer Xavier Querol Centre for Innovation on Carbon Capture and Storage Institute of Mechanical Process and Energy Engineering Heriot-Watt University Institute of Environmental Assessment and Water Research

Experimental and geochemical modelling studies were carried out to identify mineral and solid phases containing major, minor, and trace elements and the mechanism of the retention of these elements in Flue Gas Desulphurisation（FGD）-gypsum samples from a coal-fired power plant under filtered water recirculation to the scrubber and forced oxidation conditions. The role of the p H and related environmental factors on the mobility of Li, Ni, Zn, As, Se, Mo, and U from FGD-gypsums for a comprehensive assessment of element leaching behaviour were also carried out. Results show that the extraction rate of the studied elements generally increases with decreasing the p H value of the FGD-gypsum leachates. The increase of the mobility of elements such as U, Se, and As in the FGD-gypsum entails the modification of their aqueous speciation in the leachates; UO2SO4, H2 Se, and HAs O2 are the aqueous complexes with the highest activities under acidic *** speciation of Zn, Li, and Ni is not affected in spite of p H changes; these elements occur as free cations and associated to SO4 ^2 in the FGD-gypsum leachates. The mobility of Cu and Mo decreases by decreasing the p H of the FGD-gypsum leachates, which might be associated to the precipitation of Cu Se2 and Mo Se2, respectively. Time-of-Flight mass spectrometry of the solid phase combined with geochemical modelling of the aqueous phase has proved useful in understanding the mobility and geochemical behaviour of elements and their partitioning into FGD-gypsum samples.

关键词： Geochemical modelling studies Trace elements Leaching Landfills FGD-gypsum ToF mass spectrometry

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Brazilian traditional medicine:Historical basis,features and potentialities for pharmaceutical development

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Journal of Traditional Chinese Medical Sciences 2021年第S1期8卷 44-50页

作者： Fernão castro Braga Faculty of Pharmacy Federal University of Minas GeraisAv.Ant(o)nio Carlos 6627campus PampulhaBelo Horizonte30.140-170Brazil

This article gives a brief overview on the Brazilian traditional medicine,starting from its historical development based on the cultural mixing of indigenous populations,European colonizers,and African *** the sequence,it analyzes some features that contributed to the gradual loss of interest on medicinal plants in Brazil,a process started in the 1950s,and recent initiatives undertaken to valuate the Brazilian traditional ***,it highlights some drugs developed from or based on con-stituents of the Brazilian biodiversity and traditional knowledge,which are globally employed,and the perspectives for new drugs *** also discusses the sanitary requirements currently adopted in Brazil for the development and registration of medicinal products based on the Brazilian biodiversity and associated traditional knowledge,as well as the impact of new *** addition,it is presented a discussion on the regulatory framework to access to genetic heritage and associated traditional knowledge in Brazil,along with its impact on the development of pharmaceutical ***,some attempts are made to indicate the possible causes that limit the development of products based on the genetic heritage of Brazilian plants and associated traditional knowledge.

关键词： features globally starting

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In Silico and in Vitro Analysis of Pyrazolone Derivatives against Zika Virus and Identification of Potential NS5 Methyltransferase Inhibitors by Molecular Docking

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Journal of Biosciences and Medicines 2024年第7期12卷 214-229页

作者： Luciene Soares Silva Tiago Soares Barbosa Maria Leonisa Sanchez-Nuñez Aldenise Mont Serrat Rosa da Silva Vitor Won-Held Rabelo Leonardo dos Santos Corrêa Amorim Leonardo Alves Miceli Percilene Fazolin Vegi Alice Bernardino Helena Carla castro Izabel Christina Nunes de Palmer Paixão Science and Biotechnology Graduate Program Department of Cellular and Molecular Biology Institute of Biology Fluminense Federal University Niteri Brazil Science and Biotechnology Graduate Program Department of Cellular and Molecular Biology Institute of Biology Fluminense Federal University Niterói Brazil Laboratory of Antibiotics Biochemistry Teaching and Molecular Modeling Institute of Biology Fluminense Federal University Niterói Brazil Laboratory of Organic Chemistry at the Institute of Chemistry Institute of Biology Fluminense Federal University Niterói Brazil

Zika virus (ZIKV), a mosquito-borne flavivirus, has been associated with benign infections for decades. However, it has become a public health concern due to its association with severe fetal and neurological complications. Although many efforts have been made to control ZIKV infection, approved vaccines or antiviral drugs are still lacking. Consequently, the development of new effective anti-ZIKV agents is urgently needed. In this context, we investigated the antiviral potential of pyrazolone derivatives against ZIKV replication using in silico and in vitro methods. The four pyrazolone derivatives evaluated (1a, 1b, 1c, and 1d) inhibited over 50% of ZIKV replication with low cytotoxicity. Among them, compound 1b exhibited the most potent activity (EC50 = 4.3 μM) and the highest selectivity (SI = 342). Mechanism of action studies indicated that these compounds act at early stages of virus replication, and compound 1b can also directly inactivate ZIKV particles. Molecular docking studies suggested that these compounds can bind to and block the activity of ZIKV NS5 methyltransferase. Finally, pharmacokinetic and toxicological predictions have reinforced the safety and drug-like profiles of these derivatives. In conclusion, the pyrazolone scaffold proved to be valuable for anti-ZIKV drug development, and the derivatives studied deserve further investigation.

关键词： Zika Pyrazolone NS5 Methyltransferase Antivirals

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A multi-integrated approach on toxicity effects of engineered TiO2 nanoparticles

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Frontiers of Environmental Science & Engineering 2015年第5期9卷 793-803页

作者： Ana PICADO Susana M. PAIXAO Liliana MOITA Luis SILVA mario S. DINIZ Joana LOURENCO Isabel PERES Luisa castro Jose Brito CORREIA Joana PEREIRA Isabel FERREIRA Antonio Pedro Alves MATOS Pedro BARQUINHA Elsa MENDONCA LNEG-National Laboratory of Energy and Geology I.P. Lisbon 1649-038 Portugal REQUIMTE Chemistry Department Fine Chemistry and Biotechnology Center Faculty of Sciences and Technology New University of Lisbon Caparica 2829-516 Portugal IMAR-Ocean Institute Department of Sciences and Environmental Engineering Faculty of Sciences and Technology New University of Lisbon Caparica 2829-516 Portugal CENIMAT/I3N and Department of Materials Science Faculty of Sciences and Technology New University of Lisbon Caparica 2829-516 Portugal Pathological Anatomy Curry Cabml Hospital Lisbon 1069-166 Portugal CESAM Faculty of Sciences Lisbon University Lisbon 1749-016 Portugal

The new properties of engineered nanoparti- cles drive the need for new knowledge on the safety, fate, behavior and biologic effects of these particles on organisms and ecosystems. Titanium dioxide nanoparticles have been used extensively for a wide range of applica- tions, e.g, self-cleaning surface coatings, solar cells, water treatment agents, topical sunscreens. Within this scenario increased environmental exposure can be expected but data on the ecotoxicological evaluation ofnanoparticles are still scarce. The main purpose of this work was the evaluation of effects of TiO2 nanoparticles in several organisms, covering different trophic levels, using a battery of aquatic assays. Using fish as a vertebrate model organism tissue histological and ultrastructural observations and the stress enzyme activity were also studied. TiO2 nanoparticles （Aeroxide~ P25）, two phase composition ofanatase （65%） and rutile （35%） with an average particle size value of 27.64-11 nm were used. Results on the ECs0 for the tested aquatic organisms showed toxicity for the bacteria, the algae and the crustacean, being the algae the most sensitive tested organism. The aquatic plant Lemna minor showed no effect on growth. The fish Carassius auratus showed no effect on a 21 day survival test, though at a biochemical level the cytosolic Glutathione-S-Transferase total activity, in intestines, showed a general significant decrease （p〈0.05） after 14 days of exposure for all tested concentrations. The presence of TiO2 nanoparticles aggregates were observed in the intestine lumen but their internalization by intestine cells could not be confirmed.

关键词： ecotoxicity enzymatic analysis histology,transmission electron microscopy (TEM) TiO2-nanoparti-cles

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ADAM17/TACE:a key molecule in brain injury regeneration

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Neural Regeneration Research 2019年第8期14卷 1378-1379页

作者： Samuel Dominguez-Garcia Carmen castro Noelia Geribaldi-Doldan Area de Fisiologia Facultad de Medicina Universidad de Cadiz Cadiz Spain Instituto de Investigacion e Innovacion Biomedica de Cadiz (INIBICA) Universidad de Cadiz Cadiz Spain

It has been many years since "the tumor necrosis factor-a-converting enzyme”,also known as ADAM17/TACE, was described as "the enzyme that does it all” because of its role in neurodegenerative diseases and in several physiological processes including proteolysis, adhesion, intracellular signaling, migration and proliferation. ADAM17/TACE is an integral membrane protein that belongs to the disintegrin and metalloprotease (ADAM) family. Several years ago, Romero-Grimaldi et al.

关键词： ADAM17/TACE key molecule injury regeneration

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