8,304 research outputs found
Antimicrobial efficacy of low concentration PVP-silver nanoparticles deposited on DBD plasma-treated polyamide 6,6 fabric
In this study, a low concentration (10 Îźg¡mLâ1) of poly(N-vinylpyrrolidone) (PVP)-coated silver nanoparticles (AgNPs) were deposited by spray and exhaustion (30, 70 and 100 âŚC) methods onto untreated and dielectric barrier discharge (DBD) plasma-treated polyamide 6,6 (PA66) fabric. DBD plasma-treated samples showed higher AgNP deposition than untreated ones for all methods. After five washing cycles, only DBD plasma-treated samples displayed AgNPs on the fabric surface. The best-performing method was exhaustion at 30 âŚC, which exhibited less agglomeration and the best antibacterial efficacy against S. aureus (4 log reduction). For E. coli, the antimicrobial effect showed good results in all the exhaustion samples (5 log reduction). Considering the spray method, only the DBD plasma-treated samples showed some bacteriostatic activity for both strains, but the AgNP concentration was not enough to have a bactericidal effect. Our results suggest DBD plasma may be a low cost and chemical-free method for the preparation of antibacterial textiles, allowing for the immobilization of a very lowâbut effectiveâconcentration of AgNPs.This work was funded by European Regional Development funds (FEDER) through the Competitiveness and Internationalization Operational Program (POCI) â COMPETE and by National Funds through FundaçaĚo para a CieĚncia e Tecnologia (FCT)âunder the project POCI-01-0145-FEDER-007136 and UID/CTM/00264/2019. Isabel Ribeiro (SFRH/BD/137668/2018) acknowledges FCT, Portugal, for its doctoral grant financial support. A. Zille also acknowledges financial support of the FCT through an Investigator FCT Research contract (IF/00071/2015) and the project PTDC/CTM-TEX/28295/2017 financed by FCT, FEDER and POCI in the frame of the Portugal 2020 program
Tratamento de efluente têxtil atravÊs de processo oxidativo avançado (H2O2/TiO2/UV)
Em toda indĂşstria ocorre grande geração de efluentes, geralmente com alta demanda biolĂłgica de oxigĂŞnio (DBO) e demanda quĂmica de oxigĂŞnio (DQO). Tratamentos convencionais permitem apenas a transferĂŞncia de fase do poluente, resolvendo o problema de maneira parcial. Os processos oxidativos avançados (POA), que se baseiam na formação de radicais hidroxilas (â˘OH) de alto poder oxidante, tem ganhado cada vez mais espaço como tĂŠcnica de tratamento de efluente. Para esse trabalho foi utilizado a tĂŠcnica de fotocatĂĄlise heterogĂŞnea (H2O2/TiO2/UV) em reator tubular do tipo anular assistido por lâmpada de luz negra. Para otimização do processo foi utilizado planejamento fatorial com 2 variĂĄveis independentes, concentração de H2O2 e TiO2. Esse trabalho tem o objetivo de estudar o tratamento de efluente industrial atravĂŠs de POA do tipo fotocatĂĄlise heterogĂŞnea, com a finalidade de reuso de ĂĄgua na indĂşstria ou para outros fins. A solução teste utilizada experimentalmente foi produzida em laboratĂłrio com o corante remazol preto B 133%. As melhores condiçþes de degradação de corante quando utilizados as concentraçþes de 200 mM e 0,5 g/L de H2O2 e TiO2, respectivamente. Na anĂĄlise de custo foi estimado o valor de R$ 255,24/m3, levando-se em consideração custos de reagentes quĂmicos, energia e equipamentos
Serologic Survey of Hantavirus Infection, Brazilian Amazon
Federal University of MaranhĂŁo. SĂŁo LuĂs, MA, Brazil.Federal University of MaranhĂŁo. SĂŁo LuĂs, MA, Brazil.Federal University of MaranhĂŁo. SĂŁo LuĂs, MA, Brazil.Federal University of MaranhĂŁo. SĂŁo LuĂs, MA, Brazil.Federal University of MaranhĂŁo. SĂŁo LuĂs, MA, Brazil.Federal University of MaranhĂŁo. SĂŁo LuĂs, MA, Brazil.State Department of Health. SĂŁo LuĂs, MA, Brazil.MinistĂŠrio da SaĂşde. Secretaria de Vigilância em SaĂşde. Instituto Evandro Chagas. BelĂŠm, PA, Brasil.MinistĂŠrio da SaĂşde. Secretaria de Vigilância em SaĂşde. Instituto Evandro Chagas. BelĂŠm, PA, Brasil
Reference evapotranspiration in the irrigated perimeters of the state of Sergipe
O conhecimento da evapotranspiração de referĂŞncia (ETo) ĂŠ essencial no manejo de irrigação de culturas agrĂcolas em todo o mundo. Neste trabalho se utilizaram dados meteorolĂłgicos diĂĄrios de evaporação do tanque "Classe A", temperaturas mĂĄximas e mĂnimas, insolação, velocidade do vento a 2 m de altura e umidade relativa do ar, referentes ao perĂodo de 1989 a 1993, coletados em quatro perĂmetros irrigados do Estado de Sergipe, para estimativa da ETo com base nos mĂŠtodos do Tanque Classe "A", Radiação Solar, Hargreaves & Samani, Linacre e Penman-Monteith (FAO/56). Comparam-se os valores diĂĄrios da ETo para a regiĂŁo estudada, atravĂŠs dos quais, quando comparados com o modelo de Penman-Monteith (FAO/56) se obtiveram os melhores desempenhos com os mĂŠtodos que utilizam a radiação solar como dado de entrada no modelo. O mĂŠtodo do Tanque Classe "A" nĂŁo apresentou desempenho satisfatĂłrio em nenhum perĂmetro irrigado estudado. _________________________________________________________________________________________ ABSTRACT: The knowledge of reference evapotranspiration (ETo) is essential for the irrigation scheduling of crops throughout the world. This work used daily meteorological data of Class A pan evaporation, maximum and minimum air temperatures, insolation, wind speed at 2 m above surface and relative humidity from 1989 to 1993 for four irrigated perimeters of Sergipe. These data were used for estimating ETo based on the following methods: Class A pan evaporation, Solar Radiation, Hargreaves & Samani, Linacre and Penman-Monteith (FAO/56). The daily values of ETo were compared to those obtained by FAO Penman-Monteith method in order to choose the best method of estimating ETo for the region. The best performance was obtained for those models which used the solar radiation as the data input. The Class A pan evaporation method did not show favorable performance in any irrigated perimeter
Preliminary in vitro evaluation of the anti-proliferative activity of guanylhydrazone derivatives
Guanylhydrazones have shown promising antitumor activity in preclinical tumor models in several studies. In this study, we aimed at evaluating the cytotoxic effect of a series of synthetic guanylhydrazones. Different human tumor cell lines, including HCT-8 (colon carcinoma), MDA-MB-435 (melanoma) and SF-295 (glioblastoma) were continuous exposed to guanylhydrazone derivatives for 72 hours and growth inhibition of tumor cell lines and macrophages J774 was measured using tetrazolium salt (MTT) assay. Compounds 7, 11, 16 and 17 showed strong cytotoxic activity with IC50 values lower than 10 Îźmol Lâ1 against four tumor cell lines. Among them, 7 was less toxic to non-tumor cells. Finally, the obtained data suggest that guanylhydrazones may be regarded as potential lead compounds for the design of novel anticancer agents
Measurement of the t t-bar production cross section in the dilepton channel in pp collisions at sqrt(s) = 7 TeV
The t t-bar production cross section (sigma[t t-bar]) is measured in
proton-proton collisions at sqrt(s) = 7 TeV in data collected by the CMS
experiment, corresponding to an integrated luminosity of 2.3 inverse
femtobarns. The measurement is performed in events with two leptons (electrons
or muons) in the final state, at least two jets identified as jets originating
from b quarks, and the presence of an imbalance in transverse momentum. The
measured value of sigma[t t-bar] for a top-quark mass of 172.5 GeV is 161.9 +/-
2.5 (stat.) +5.1/-5.0 (syst.) +/- 3.6(lumi.) pb, consistent with the prediction
of the standard model.Comment: Replaced with published version. Included journal reference and DO
Combined search for the quarks of a sequential fourth generation
Results are presented from a search for a fourth generation of quarks
produced singly or in pairs in a data set corresponding to an integrated
luminosity of 5 inverse femtobarns recorded by the CMS experiment at the LHC in
2011. A novel strategy has been developed for a combined search for quarks of
the up and down type in decay channels with at least one isolated muon or
electron. Limits on the mass of the fourth-generation quarks and the relevant
Cabibbo-Kobayashi-Maskawa matrix elements are derived in the context of a
simple extension of the standard model with a sequential fourth generation of
fermions. The existence of mass-degenerate fourth-generation quarks with masses
below 685 GeV is excluded at 95% confidence level for minimal off-diagonal
mixing between the third- and the fourth-generation quarks. With a mass
difference of 25 GeV between the quark masses, the obtained limit on the masses
of the fourth-generation quarks shifts by about +/- 20 GeV. These results
significantly reduce the allowed parameter space for a fourth generation of
fermions.Comment: Replaced with published version. Added journal reference and DO
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