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Search Results: 1 - 10 of 615666 matches for " P. S. C. Pereira "
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PET Oligomer Waste to Modify CAP Characteristics  [PDF]
L. C. Mendes, M. L. Dias, P. S. C. Pereira, L. M. R. Albuquerque
Materials Sciences and Applications (MSA) , 2012, DOI: 10.4236/msa.2012.38082
Abstract: To develop an improved method of reusing poly(ethylene terephthalate) (PET) waste in the production chain, it was chemically modified with pentaerythritol (PENTE), resulting in PET/PENTE (60/40) oligomer. This was added to petroleum asphalt cement (CAP) in different proportions—5, 10 and 20 wt%—as a modifier of bitumen characteristics. The mixture was evaluated by thermogravimetry (TG/DTG), differential scanning calorimetry (DSC), infrared spectroscopy (FT-IR), optical microscopy (OM) and the adhesion-peel test. The oligomer enhanced substantially the asphalt thermal stability-Tonset. OM images showed strong compatibility between components and PET’s amorphization. PET oligomer increased CAP’s wettability and the mixture presented cohesive fracture through the peel test. The mixture has excellent potential as paving material.
Energy Efficiency and Renewable Energy Technologies Using Smart Grids: Study Case on NIPE Building at UNICAMP Campus  [PDF]
M. D. Berni, P. C. Manduca, S. V. Bajay, J. T. V. Pereira, J. T. Fantinelli
Smart Grid and Renewable Energy (SGRE) , 2014, DOI: 10.4236/sgre.2014.58018
Abstract: In its broadest interpretation, the smart grid vision sees the future of power industry transformed by the introduction of intelligent two-way communications, ubiquitous metering and measurement. This enables much finer control of energy flows and the integration and efficient use of renewable forms of energy, energy efficiency methodologies and technologies, as well as many other advanced technologies, techniques and processes that wouldn’t have been practicable until present. The smart grid vision also enables the creation of more reliable, more robust and more secure power supply infrastructure, and helps optimize the enormous investments required to build and operate the physical infrastructure required. The smart grid promises to revolutionize the electric power business that has been in place for the past 75 years. This work discusses the efficiency, targeted at the consumer units of electricity, with a view to sustainability and potential for technological innovation. The issue is addressed from two perspectives: the systems for generation and power distribution, and the design of a building “smart energy”. Because of the novelty of the subject in our country, the concepts presented and treated throughout this work come from material obtained at events and specialized sites on electric power system in Brazil and worldwide, being accompanied by information and data from NIPE’s building at University of Campinas’s campus case study in which it exemplifies the applicability of the techniques and recommended technologies.
Unusual domain growth behavior in the compressible ising model
Mitchell, S. J.;Pereira, Luiz F. C.;Landau, D. P.;
Brazilian Journal of Physics , 2008, DOI: 10.1590/S0103-97332008000100002
Abstract: large scale monte carlo simulations have been used to study long-time domain growth behavior in a compressible, two-dimensional ising model undergoing phase separation. the system is quenched below the transition temperature from a random spin state, and we investigated the late-time domain size growth law, r(t) = a + btn. for "lattice mismatched" systems, we found n = 0.224 ± 0.004 which deviates significantly from the lifshitz-slyozov value of n = 1/3 for late-time growth . for a compressible model with no mismatch, we find only a slight deviation from n = 1/3. these results strongly suggest that we do not yet fully understand domain growth.
Synthesis, Structural and Photophysical Properties of Gd2O3:Eu3+ Nanostructures Prepared by a Microwave Sintering Process  [PDF]
Ana P. de Moura, Larissa H. Oliveira, Icamira C. Nogueira, Paula F. S. Pereira, Maximo S. Li, Elson Longo, José A. Varela, Ieda L. V. Rosa
Advances in Chemical Engineering and Science (ACES) , 2014, DOI: 10.4236/aces.2014.43041
Abstract: In this paper, we report the obtention of gadolinium oxide doped with europium (Gd2O3:Eu+3) by thermal decomposition of the Gd(OH)3:Eu3+ precursor prepared by the microwave assisted hydrothermal method. These systems were analyzed by thermalgravimetric analyses (TGA/DTA), X-ray diffraction (XRD), structural Rietveld refinement method, fourrier transmission infrared absorbance spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM) and photoluminescence (PL) measurement. XRD patterns, Rietveld refinement analysis and FT-IR confirmed that the Gd(OH)3:Eu3+ precursor crystallize in a hexagonal structure and space group P6/m, while the Gd2O3
Effect of Serjania lethalis ethanolic extract on weed control Efeito do extrato etanólico de Serjania lethalis no controle de plantas daninhas
P.U. Grisi,S.C.J. Gualtieri,S. Anese,V.C. Pereira
Planta Daninha , 2013,
Abstract: The objective of this study was to evaluate the effect of the ethanolic extract of Serjania lethalis leaves and stems on the diaspore germination and seedling growth of wild poinsettia (Euphorbia heterophylla) and barnyardgrass (Echinochloa crus-galli). The crude ethanolic extract was prepared from 100 g of dry plant material dissolved in 500 ml of ethanol. The extracts were solubilized in a buffer solution containing dimethyl sulfoxide (DMSO) at concentrations of 10.0, 7.5, 5.0 and 2.5 mg mL-1. The effect of these extracts was compared with herbicide oxyfluorfen in bioassays. The ethanolic extracts of S. lethalis leaves and stems inhibited the germination and seedling growth of barnyardgrass and wild poinsettia in a concentration-dependent manner. The reduction in the root length of E. heterophylla seedlings might be attributed to the reduced elongation of metaxylem cells. The phytotoxicity of the extracts ranged according to the receptor species, and for some variables, the inhibitory effect was similar, and even superior, to that of the commercial herbicide. Thus, S. lethalis extracts might be a promising alternative for sustainable weed management. O objetivo deste estudo foi avaliar o efeito do extrato etanólico de folhas e caules de Serjania lethalis sobre a germina o dos diásporos e crescimento de plantulas de amendoim-bravo (Euphorbia heterophylla) e capim-arroz (Echinochloa crus-galli). O extrato bruto etanólico foi preparado na propor o de 100 g de material vegetal seco para 500 mL de etanol. A partir deste, os extratos foram solubilizados em solu o tamp o e dimetil sulfóxido (DMSO) nas concentra es 10,0, 7,5, 5,0 e 2,5 mg mL-1. Nos bioensaios comparou-se o efeito desses extratos com o herbicida oxyfluorfen. Os extratos etanólicos de folhas e caules de S. lethalisexerceram atividade inibitória no processo de germina o e no crescimento das plantulas de capim-arroz e amendoim-bravo, com efeito dependente da concentra o. Verificou-se que a redu o do crescimento radicular das plantulas de amendoim-bravo pode estar relacionada com a diminui o no alongamento das células do metaxilema. A fitotoxicidade dos extratos variou de acordo com a espécie receptora, sendo que para algumas variáveis o efeito inibitório foi similar e até mesmo superior ao do herbicida comercial. Desta maneira, pode-se dizer que os extratos de S. lethalis podem ser uma alternativa promissora para o manejo sustentável de plantas daninhas.
In Vivo 9.4T MRI and 1H MRS for Evaluation of Brain Structural and Metabolic Changes in the Ts65Dn Mouse Model for Down Syndrome  [PDF]
S. Même, N. Joudiou, N. Yousfi, F. Szeremeta, P. Lopes-Pereira, J. C. Beloeil, Y. Herault, W. Même
World Journal of Neuroscience (WJNS) , 2014, DOI: 10.4236/wjns.2014.42018
Abstract:

In the present study we investigated structural and metabolic modifications of the brain in the Ts65Dn mouse model of Down syndrome(DS)using both in vivo magnetic resonance imaging(MRI)and proton magnetic resonance spectroscopy(MRS). MRI was performed for further texture analysis and changes in texture parameters, including mean grey levels, contrast and homogeneity, and they were found in Ts65Dn compared to diploid littermates (2n). These phenotypic changes were different in the hippocampus and cerebellum, since in Ts65Dn mean grey levels increased in the cerebellum and decreased in the hippocampus. In addition, proton NMR spectra revealed differences in metabolite ratios. Levels of N-acetylaspartate(NAA)and glutamate(Glu), were lower compared to total creatine levels (CX), in the Ts65Dn brain. However, the most striking finding was an increase in the concentration of myo-inositol(Ins)and choline(Cho)in the hippocampus, whereas the Ins concentration was reduced in the cerebellum. Overall, these data illustrate that MRI and MRS are valuable assesment tools sufficiently sensitive to detect associated changes in different brain areas, thus providing new insight into the causative role of dosage-sensitive genes in the Ts65Dn DS mouse model.

Fluorescence of Chlorophyll a for Discovering Inhibitors of Photosynthesis in Plant Extracts  [PDF]
Ana C. de Carvalho, Jéssica P. Salvador, Thais de M. Pereira, Pedro Henrique A. Ferreira, Jo?o Carlos S. Lira, Thiago A. M. Veiga
American Journal of Plant Sciences (AJPS) , 2016, DOI: 10.4236/ajps.2016.711146
Abstract: Aims: Twelve crude extracts were prepared from different parts of Pluchea sagittalis, Cecropia palmata and Brachiaria brizantha, and their effect on the light reaction of photosynthesis. Study Design: Use of fluorescence of ChL a (Chlorophyll a) to detect inhibitors of photosynthesis in plant extracts. Place and Duration of Study: Instituto de Ciências Ambientais, Químicas e Farmacêuticas, Departamento de Ciências Exatas e da Terra, Universidade Federal de Sao Paulo (UNIFESP), between July 2015 and January 2016. Methodology: The samples had their effect on the light reaction of photosynthesis studied by Chlorophyll a (Chl a) fluorescence transient by the use of chloroplasts isolated from spinach leaves. As negative controls we used the same amounts of DMSO that have been employed to solubilize the samples, and as positive control we have used 10 μM of the commercial herbicide DCMU (Diuron). Results: The extracts inhibited the photosynthesis, and their inhibition sites were located in the range of electron flow from OEC complex and between P680 to QA of PS II, and inhibited the photosystem II (PS II) by inducing the appearance of the transient bands K and J. Conclusion: Our results suggest an indicative that the photochemical apparatus probably is failing at the donor and acceptor sides of PSII, causing damage to electron transport during the photosynthesis phenomenon.
Prepara??o e caracteriza??o de materiais híbridos celulose/NbOPO4.nH2O a partir de celulose branqueada de baga?o de cana-de-a?úcar
Pereira, Paulo H. F.;Voorwald, Herman C. J.;Cioffi, Maria O. H.;Pereira, Maria L. C. P. da S.;
Polímeros , 2012, DOI: 10.1590/S0104-14282012005000002
Abstract: this work describes the preparation and characterization of cellulose/hydrous niobium phosphate hybrid with bleached cellulose from sugarcane bagasse. the hybrid was prepared in two different forms: named methods i and ii. method i consisted in dissolving metallic niobium in a fluoridric/nitric (100:10) mixture, with aging time of 16 hours in which the sugarcane bagasse was in contact with the acid solution. phosphoric acid was then added to the solution for precipitation of the material. method ii was similar, but metallic niobium was diluted in a fluoridric /nitric (160/100) solution without aging time. in both methods different proportions of cel/nbopo4.nh2o were used: (10:10); (10:6) and (10:2). these materials were characterized by x-ray diffraction (xrd), thermogravimetry (tg/dtg) analysis and scanning electronic microscopy (sem). the deposition of niobium phosphate and an increase in crystallinity were observed.
Comparison of relative renal function measured with either 99mTc-DTPA or 99mTc-EC dynamic scintigraphies with that measured with 99mTc-DMSA static scintigraphy
Domingues, F. C.;Fujikawa, G. Y.;Decker, H.;Alonso, G.;Pereira, J. C.;Duarte, P. S.;
International braz j urol , 2006, DOI: 10.1590/S1677-55382006000400004
Abstract: objective: the aim of this study was to compare the renal function measured with either 99mtc-dtpa or 99mtc-ec dynamic scintigraphies with that measured using 99mtc-dmsa static scintigraphy. methods: the values of relative renal function measured in 111 renal dynamic scintigraphies performed either with 99mtc-dtpa (55 studies) or with 99mtc-ec (56 studies) were compared with the relative function measured using 99mtc-dmsa static scintigraphy performed within a 1-month period. the comparisons were performed using wilcoxon signed rank test. the number of 99mtc-dtpa and 99mtc-ec studies that presented relative renal function different by more than 5% from that measured with 99mtc-dmsa, using chi square test were also compared. results: the relative renal function measured with 99mtc-ec is not statistically different from that measured with 99mtc-dmsa (p = 0.97). the relative renal function measured with 99mtc-dtpa was statistically different from that measured using 99mtc-dmsa, but with a borderline statistical significance (p = 0.05). the number of studies with relative renal function different by more than 5% from that measured with 99mtc-dmsa is higher for the 99mtc-dtpa scintigraphy (p = 0.04) than for 99mtc-ec. conclusion: the relative renal function measured with 99mtc-ec dynamic scintigraphy is comparable with that measured with 99mtc-dmsa static scintigraphy, while the relative renal function measured with 99mtc-dtpa dynamic scintigraphy presents a significant statistical difference from that measured with 99mtc-dmsa static scintigraphy.
Intestinal microbiota and HIV-1 infection
Trindade, E. B. S. M.;Souza, L. R.;Lopes, C. A. M.;Pereira, P. C. M.;
Journal of Venomous Animals and Toxins including Tropical Diseases , 2007, DOI: 10.1590/S1678-91992007000200003
Abstract: the intestinal microbiota consists of a qualitatively and quantitatively diverse range of microorganisms dynamically interacting with the host. it is remarkably stable with regard to the presence of microorganisms and their roles which, however, can be altered due to pathological conditions, diet composition, gastrointestinal disturbances and/or drug ingestion. the present review aimed at contributing to the discussion about changes in the intestinal microbiota due to hiv-1 infection, focusing on the triad infection-microbiota-nutrition as factors that promote intestinal bacterial imbalance. intestinal microbiota alterations can be due to the hiv-1 infection as a primary factor or the pharmacotherapy employed, or they can be one of the consequences of the disease.
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