965 resultados para Surface molecular imprint


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The aim of the study was to test the molecular and serological prevalence of Anaplasma marginale in water buffaloes of the Marajó Island, State of Pará, Brazil. For serologic research were randomly selected 800 buffaloes and for molecular research 50 of these animals were randomly chosen. To quantify the serological prevalence we used the indirect enzyme linked immunosorbent assay (iELISA) with total antigen containing proteins outer surface. To quantify the prevalence molecular was used the polymerase chain reaction (PCR) involving gene amplification fragment larger surface protein 5 (MSP5). The prevalence of positive animals in iELISA was 25% (200/800). In the PCR we detected the presence of A. marginale in 2% (1/50) of animals. Although only one animal was positive in PCR, we found that it was negative in ELISA. The presence of the agent, even in low prevalence, shows that buffaloes can act as an important reservoir for transmission of the pathogen to cattle in northern Brazil.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Background. Reduced surface tension of liquids results in higher surface wetting ability and diffusivity by the substrate. Objectives. The objective of this study was to evaluate the influence of the Grander Technology in reducing the surface tension of adhesive systems. Methods. Two adhesive systems (self-etch and total-etch) were modified by physical contact with the Grander system Flexible unit to revitalize water, for 48 h. Surface tension of adhesive systems and water in normal and grander-modified conditions was measured with a goniometer. Results. The results showed a reduction of surface tension for all conditions grander-modified between 3-15%. Conclusions. Grander Technology was effective in reducing the surface tension of the Single Bond and Clearfil SE Bond adhesive systems. Clinical significance. Grander technology was employed to restructure the molecular structure of water-based adhesive systems, which can increase their wetness capacity and therefore ensure a greater diffusibility.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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In this work we report the surface modification of different engineering polymers, such as, polyethylene terephthalate (PET), polyethylene (PE) and polypropylene (PP) by an atmospheric pressure plasma jet (APPJ). It was operated with Ar gas using 10 kV, 37 kHz, sine wave as an excitation source. The aim of this study is to determine the optimal treatment conditions and also to compare the polymer surface modification induced by plasma jet with the one obtained by another atmospheric pressure plasma source the dielectric barrier discharge (DBD). The samples were exposed to the plasma jet effluent using a scanning procedure, which allowed achieving a uniform surface modification. The wettability assessments of all polymers reveal that the treatment leads to reduction of more than 40 degrees in the water contact angle (WCA). Changes in surface composition and chemical bonding were analyzed by x-ray photoelectron spectroscopy (XPS) and Fourier-Transformed Infrared spectroscopy (FTIR) that both detected incorporation of oxygen-related functional groups. Surface morphology of polymer samples was investigated by Atomic Force Microscopy (AFM) and an increase of polymer roughness after the APPJ treatment was found. The plasma-treated polymers exhibited hydrophobic recovery expressed in reduction of the O-content of the surface upon rinsing with water. This process was caused by the dissolution of low molecular weight oxidized materials (LMWOMs) formed on the surface as a result of the plasma exposure. (C) 2014 Elsevier B.V. All rights reserved.

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It is often assumed that the hydrogen atoms in the thiol groups of a benzene-1,4-dithiol dissociate when Au-benzene-1,4-dithiol-Au junctions are formed. We demonstrate, by stability and transport property calculations, that this assumption cannot be made. We show that the dissociative adsorption of methanethiol and benzene-1,4-dithiol molecules on a flat Au(111) surface is energetically unfavorable and that the activation barrier for this reaction is as high as 1 eV. For the molecule in the junction, our results show, for all electrode geometries studied, that the thiol junctions are energetically more stable than their thiolate counterparts. Due to the fact that density functional theory (DFT) within the local density approximation (LDA) underestimates the energy difference between the lowest unoccupied molecular orbital and the highest occupied molecular orbital by several electron-volts, and that it does not capture the renormalization of the energy levels due to the image charge effect, the conductance of the Au-benzene-1,4-dithiol-Au junctions is overestimated. After taking into account corrections due to image charge effects by means of constrained-DFT calculations and electrostatic classical models, we apply a scissor operator to correct the DFT energy level positions, and calculate the transport properties of the thiol and thiolate molecular junctions as a function of the electrode separation. For the thiol junctions, we show that the conductance decreases as the electrode separation increases, whereas the opposite trend is found for the thiolate junctions. Both behaviors have been observed in experiments, therefore pointing to the possible coexistence of both thiol and thiolate junctions. Moreover, the corrected conductance values, for both thiol and thiolate, are up to two orders of magnitude smaller than those calculated with DFT-LDA. This brings the theoretical results in quantitatively good agreement with experimental data.

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A criptosporidiose, é a enfermidade de veiculação hídrica, possui como agravante a dificuldade de prevenção da contaminação ambiental e ausência de medidas terapêuticas eficazes. Com acentuada importância na bovinocultura, ocasiona inflamação e atrofia das vilosidades intestinais resultando em perda da superfície de absorção. Este estudo teve como objetivo realizar a caracterização molecular da infecção por Cryptosporidium spp. em bezerros do Município de Formiga, Minas Gerais. Um total de 300 amostras de fezes de bezerros holandeses, Nelore e sem raça definida saudáveis foram avaliadas pela técnica de coloração contraste negativo de verde malaquita e por meio da reação de Nested-PCR para amplificação de fragmentos de DNA da subunidade 18S do gene do RNA ribossômico. Ocorrência de 5,33% (16/300) pelo verde malaquita e 4,66% (14/300), pela PCR foi observada, sendo que nenhuma correlação foi verificada entre a positividade e as variáveis estudadas. Por meio da caracterização molecular foram identificadas as espécies Cryptosporidium andersoni e Cryptosporidium ryanae. Como conclusão, observou-se baixa ocorrência da infecção e eliminação de oocistos por Cryptosporidium spp, ausência de sinais clínicos nos animais, houve forte concordância entre os resultados obtidos por meio das duas técnicas utilizadas e pela caracterização molecular (Nested-PCR) foram diagnosticadas as espécies C. andersoni e C. ryanae, presentes em faixas etárias não relatadas na literatura. Estas duas espécies de Cryptosporidium supracitadas são descritas pela primeira vez, parasitando bovinos no estado de Minas Gerais.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The synergistic effect produced by metallic nanoparticles when incorporated into different systems empowers a research field that is growing rapidly. In addition, organometallic materials are at the center of intensive research with diverse applications such as light-emitting devices, transistors, solar cells, and sensors. The Langmuir-Blodgett (LB) technique has proven to be suitable to address challenges inherent to organic devices, since the film properties can be tuned at the molecular level. Here we report a strategy to incorporate gold nanoparticles (AuNPs) into the LB film by co-deposition in order to achieve surface-enhanced Raman scattering (SERS) of the zinc(II)-protoporphyrin (IX) dimethyl ester (ZnPPIX-DME). Prior to the LB co-deposition, the properties of the Langmuir monolayer of ZnPPIX-DME at the air-water interface, containing AuNPs in the subphase, are studied through the surface-pressure versus mean molecular area (π-A) isotherms. The ZnPPIX-DME+AuNPs π-A isotherm presented a significant shift to higher molecular area, suggesting an interaction between both ZnPPIX-DME molecules and AuNPs. Those interactions are a key factor allowing the co-deposition of both AuNPs and ZnPPIX-DME molecules onto a solid substrate, thus forming the LB film. SERS of ZnPPIX-DME was successfully attained, ensuring the spatial distribution of the AuNPs. Higher enhancement factors were found at AuNP aggregates, as a result of the intense local electromagnetic field found in the metal nanoparticle aggregates. The main vibrational bands observed in the SERS spectra suggest a physical adsorption of the ZnPPIX-DME onto the surface of AuNPs. The latter is not only in agreement with the interactions pointed out by the π-A isotherms but also suggests that this interaction is kept upon LB film co-deposition.