Epidemiological aspects of astrovirus and coronavirus in poults in the South Eastern Region of Brazil

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

Germinação de sementes de Dyckia tuberosa (Vell.) Beer (Bromeliaceae) sob diferentes temperaturas em luz e escuro

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

Cinética de degradação do ácido ascórbico em ameixas liofilizadas

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

Parâmetros do teste de envelhecimento acelerado para determinação do vigor de sementes de feijão

O vigor de sementes representa atributos da qualidade fisiológica não revelados pelo teste de germinação. O teste de envelhecimento acelerado é realizado em condições de elevadas temperaturas e umidade relativa do ar por períodos curtos, logo estudos a respeito da utilização de temperaturas de 43 a 45 °C e a redução do período de envelhecimento são possibilidades que merecem reflexão. No estudo foi objetivo a análise dos efeitos de temperaturas e períodos de exposição ao teste de envelhecimento acelerado para identificar o vigor de sementes de feijão e características relativas ao genótipo. O delineamento experimental foi o inteiramente casualizado, foram utilizados 20 genótipos de feijão, sendo que as sementes foram submetidas a cinco períodos de envelhecimento acelerado (12, 24, 36, 48 e 60 h) e três temperaturas (41, 43 e 45 °C). Foram avaliados também germinação, primeira contagem de germinação, velocidade de germinação e emergência de plântulas. Os genótipos de sementes não diferiram quanto ao teste de germinação, no entanto apresentaram níveis distintos de qualidade através do teste de envelhecimento acelerado. O teste de envelhecimento acelerado é conveniente quando realizado a 41 °C/48 h e 43 °C/24 h. É possível a realização do teste de envelhecimento acelerado com utilização de temperatura superior e redução do período de exposição ao teste.

Método sol-gel modificado para obtenção de alumina nanoencapsulada com terras raras

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

Avaliação da resistência à corrosão de aços inoxidáveis com Nb endurecíveis por precipitação

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Efeitos da temperatura e da movimentação do ar sobre o isolamento térmico do velo de ovinos em câmara climática

Foram utilizados dez ovinos da raça Corriedale - cinco machos e cinco fêmeas com pesos entre 52,2 e 87,6 kg - com o objetivo de avaliar o efeito da combinação da movimentação do ar (0 e 5,0 m/s) com a temperatura do ar (25, 30 e 40ºC) sobre a temperatura retal (T R, ºC), da epiderme (T E, ºC), da superfície do velo (T V, ºC) e do interior do velo (T I, ºC) e a espessura do velo (E V, cm) e suas relações com o isolamento térmico do velo. A presença de vento não teve efeito sobre as variáveis estudadas, o que sugere que fluxo de ar (<5,0 m/s) paralelo ao eixo corporal do animal tem pouco efeito sobre o isolamento térmico do velo, independentemente da temperatura do ar, que se mostrou altamente correlacionada, de forma positiva, com as temperaturas retal, do velo, do interior do velo e da epiderme. Sob temperaturas inferiores a 30ºC, a transferência de calor através do velo ocorreu via condução e convecção livre, enquanto sob altas temperaturas (>40ºC) o fluxo de calor sensível não foi significativa.

Thermal degradation of geomembranes after exposure to heat

HDPE and PVC geomembranes are sensitive to changes in their properties when in contact with high temperatures. The effects of hot temperature on polymeric geomembranes are assessed by the ASTM D794 and ASTM D5721.This paper brings an analysis of degradation of the Poly Vinyl Chloride (PVC) and High Density Poly Ethylene (HDPE) geomembranes when exposed to conventional and air oven after specific periods.. Mechanical and physical properties were evaluated. OIT tests were also performanced to evaluate the level of oxidation degradation occurred on the HDPE geomembranes. Geomembranes of two thicknesses were tested: 1.0, 2.0 nun (PVC) and 0.8, 2.5 mm, (HDPE). The results obtained show, for example, that after the last period of exposure, the PVC geomembranes (1.0, 2.0 mm) were more rigid and stiffer than fresh samples. The HDPE geomembranes, on the other hand, when exposed to heat presented increases in deformation. OIT tests showed efficient to detect some level of degradation on the HDPE geomembranes.

Microwave synthesis of YAG : Eu by sol-gel methodology

Yttrium-aluminum oxides are interesting compounds and they have been extensively used as host for lasers and phosphors, due to their stable physical and chemical properties. The fabrication of yttrium-aluminum garnet (YAG) has been investigated thoroughly. Single-crystal YAG is expensive and to produce it a new way has been investigated. This process consists of modifying the methodology of reagents mixture and the process of heating them. The microwave irradiation is used to heat-treat the oxide mixture. The traditional synthesis of YAG powders occurs through the reaction of aluminum and yttrium powders at high temperatures. With this work we investigated the preparation of YAG by non-hydrolytic sol-gel route as an alternative methodology to obtain yttrium-aluminum matrix from inorganic precursors (yttrium and aluminum chloride). The preparation of the gel was carried out in an oven-dried glassware. The AlCl3, YCl3 and ethanol were reacted in reflux under argon atmosphere. Europium III chloride was added as a structural probe. The powder was dried and heat-treated in modified microwaves. The samples were pre-treated at 50 and 800 C during I h and then heated in microwaves for 30 s, 2 and 4 min. The formation process and structure of the powders were studied by means of X-ray diffraction (XRD), photoluminescence (PL) and transmission electronic microscopy (TEM). XRD presents only picks corresponding to the YAG phase and confirmed by TEM. PL date showed that the YAG phase was formed in 2 min with the samples pre-treated at 50 C. For the samples pretreated at 800 degrees C, the YAG phase appears in 30s. The excitation spectra present a maximum of 394 nm corresponding to the L-5(6) level and emission spectra of Eu III ion present bands characteristic transitions arising from the D-5(0) -> F-7(J) (J= 1, 2, 3, 4) monifolds excited at their maximum. The magnetic dipole D-5(0) -> F-7(1) transition presents more intensity than the electric dipole D-5(0) -> F-7(2) transition. This methodology showed efficiency in obtaining YAG phase. (c) 2006 Elsevier B.V. All rights reserved.

Phosphate functionalization of spongiolite surface

Spongiolite from Mato Grosso do Sul (Brazil), natural inorganic composite constituted of silica needles, was treated with concentrated phosphoric acid at high temperatures. Superficial coating of the needles was proved to be constituted of silicon diphosphate, a compound offering six-coordinated silicon sites. Owing to the affinity of three charged ions to phosphate groups, this coating acts as specific adsorbent for the rare earth elements which prefer octahedral coordination (starting from samarium, yttrium included). The uptake of lanthanum and neodymium are significantly lower due to different coordination tendencies. Lanthanide fixation upon silica with PO4 groups anchored on its surface may be useful in the manufacturing of special phosphate-silicate glasses. (C) 2003 Elsevier B.V. All rights reserved.

Gelatin-immobilized pectinmethylesterase for production of low methoxyl pectin

The optimum conditions for the production of low methoxyl pectin using pectinmethylesterase (PME) from acerola (Malpighia glabra L.), immobilized in gelatin, have been established by factorial design and response surface methodology. In the case of the free enzymes the optimum conditions for activity, within ranges adequate for food processing, are low NaCl concentrations (0.10 M), relatively high temperatures (55 degreesC) and slightly basic pH values (pH = 9). The temperature and pH seem to have strong influence on the observed activity. In the immobilized enzyme, optimum NaCl concentration was 0.15 M, while the optimum pH remained at 9.0. (C) 2003 Elsevier Ltd. All fights reserved.

A model for the Schottky anomaly in metallic Nd2-yCeyCuO4

We present a simple model for the doped compound Nd2-yCevCuO4, in order to explain some recent experimental results on the latter. Within a Hartree-Fock context, we start from an impurity Anderson-like model and consider the magnetic splitting of the Nd-4f ground state Kramers doublet due to exchange interactions with the ordered Cu moments. Our results are in very good agreement with the experimental data, yielding a Schottky anomaly peak for the specific heat that reduces its amplitude, broadens and shifts to lower temperatures, upon Ce doping. For overdoped compounds at low temperatures, the specific heat behaves linearly and the magnetic susceptibility is constant. A smooth transition from this Fermi liquid-like behavior occurs as temperature is increased and, at high temperatures, the susceptibility exhibits a Curie-like behavior. Finally, we discuss some improvements our model is amenable to incorporate, (C) 1998 Elsevier B.V. B.V. All rights reserved.

Thermal diffusivity analysis of doped poly(methyl-methacrylate) with electron donor and acceptor molecules

A computer-assisted method for analysing photoacoustic spectra has been developed in the Windows(TM) environment with the use of an easy graphical interface, the computer simulation was carried out with the aim of using the entire expression of the Rosencwaig-Gersho theory, thus permitting multiple applications. The simulation was applied to a system that mimics the electron transfer process in which the concentration of octaethylporphin donor molecules was constant whereas the concentration of duroquinone and 2,3-dichloro-5,6-dicyano-1, l-benzoquinone acceptor molecules varied. The increment of the acceptor concentration influenced the photoacoustic amplitude and phase signals. In the phase signal a significant shift to smaller values was observed, denoting a faster heat generation. The analysis of the photoacoustic signal enabled the determination of the thermal diffusivity, the result obtained through the simulation was about (7 +/- 1) x 10(-7) m(2) s(-1) indicating that changes in the photoacoustic phase signals were due to the electron transfer process rather than changes in the thermal properties of the sample.

Sex determination studies in two species of teleost fish, Oreochromis niloticus and Leporinus elongatus

Genetic analyses of sex determination have identified sex chromosomes in many teleost fish species. However, there are several cases for which sex ratios do not fit perfectly with the expectations of heterogametic systems, suggesting the influence of either minor sex determining genes or environmental influences on the process of sex differentiation. The frequent absence of sex chromosome markers makes the identification of minor sex-determining genes very difficult. It is easier to test first the hypothesis of environmental sex determination (ESD) by studying the temperature effect, since temperature-dependent sex determination has been demonstrated to occur in several vertebrate groups including 1 fish species. To contribute to a better understanding of fish sex determination, we have tested the effects of high temperatures on sex ratios of Oreochromis niloticus, and have attempted to isolate sex chromosome molecular markers in Leporinus elongatus. Treatments of O. niloticus fry at 36 degrees C applied for 10 days and more, and starting 1 week after fertilization markedly increased the proportion of males, and progeny-testing these males confirmed that some of them are sex-reversed genetic females. Two non-coding sequences of L. elongatus Z and W chromosomes were cloned by genomic subtraction. They cross-hybridized with the genome of a close species without providing sex-specific patterns. A collection of L. elongates individuals was subjected to gonadal and chromosomal sexing, and DNA hybridization with both sequences. These analyses revealed 3 individuals having atypical W chromosomes. Interestingly, 2 of these were males having a ZW karyotype. We assume that these atypical sex chromosome arise by exchanges between Z and W chromosomes, and that a transition between female and male heterogamety is underway in this species.

Nanostructure and properties of ZnO films produced by the pyrosol process

Indium doped ZnO films were deposited by the pyrosol process on glass substrates at different temperatures from solutions containing In/Zn molar ratios up to 10%. The nanostructure of the films was investigated using grazing-incidence small angle X-ray scattering (GISAXS). The mass density was determined by X-ray reflectivity and the composition by X-ray photoelectron spectroscopy. The GISAXS measurements revealed an anisotropic pattern for films deposited at 573 and 623 K and a isotropic one for those deposited at higher temperatures. The anisotropic patterns indicate the presence of elongated nanopores with their long axes perpendicular to the film surface. In contrast, the isotropic nature of GISAXS patterns of films grown at high temperatures (673 and 723 K) suggests the presence of spherical voids. The pore size distribution function determined from the isotropic patterns indicates a multimodal size distribution. on the other hand, the measured mass density of the doped films with isotropic nanotexture is higher than that of the anisotropic films while the electric resistivity is significantly lower. This is in agreement with the detected strong reduction of the void density and specific surface area at approximately constant pore size.