Antigenic typing of brazilian rabies virus samples isolated from animals and humans, 1989-2000

Amostras de vírus rábico isoladas de animais e humanos no período de 1989 a 2000 foram tipificadas antigenicamente com a utilização de um painel de anticorpos monoclonais contra a nucleoproteína viral, pré-estabelecido para o estudo da epidemiologia molecular do vírus rábico isolado nas Américas. As amostras testadas foram isoladas no laboratório de diagnóstico do Instituto Pasteur e outros centros de diagnóstico de raiva no Brasil. Além das cepas de vírus rábico fixo CVS-31/96-IP, mantida em cérebro de camundongos e a PV-BHK/97, mantida em cultura de células, cepas de vírus rábico isoladas de cães, gatos, bovinos, eqüinos, morcegos, ovinos, caprino, suínos, raposa, sagüí, coatí, guaxinim e humanos, totalizaram 330 amostras. Seis variantes antigênicas foram definidas, compatíveis com perfís observados no painel de anticorpos monoclonais pré-estabelecido utilizado, as de número 2 (cão), 3 (Desmodus rotundus), 4 (Tadarida brasiliensis), 5 (Vampiro da Venezuela), 6 (Lasiurus cinereus) e Lab (reagente a todos os anticorpos utilizados), além de outros seis perfís desconhecidos, não compatíveis com aqueles observados no painel utilizado. A maior variabilidade foi observada entre as amostras isoladas de morcegos insetívoros e a variante mais comum isolada entre as espécies foi a variante 3 (Desmodus rotundus). Estes fatos podem representar a existência de múltiplos ciclos de transmissão independentes, envolvendo diferentes espécies de morcegos.

Grain size effect on the electrical response of SnO2 thin and thick film gas sensors

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

The influence of aluminium on the overall properties of SnO2-based varistors

The influence of aluminium on the development of the microstructure and on the electrical behaviour of the SnO2 center dot Co3O4 center dot Nb2O5 typical varistor system was studied. Two sources of Al were used, alumina (Al2O3) and boehmite (AlO(OH)). The microstructural features were characterised with scanning (SEM) and transmission (TEM) electron microscopies. The different phases present in the studied samples were also studied with XRD, EDS and electron diffraction patterns of selected areas (SAED). Particles containing Sri, Co, Al, and O were unveiled with TEM. Impedance spectroscopy measurements and current density versus electric field characteristics revealed superior electrical properties for samples with AlO(OH). The higher non-linearity (alpha = 19) was achieved with the addition of 0.1% mol of boehmite. The influence of the secondary phases on the electrical properties is also addressed in this work.

Liquid chromatography/electrospray ionization tandem mass spectrometry profiling of compounds from the infusion of Byrsonima fagifolia Niedenzu

A rapid analytical approach suitable to achieve a comprehensive characterization of the compounds present in the infusion prepared from the leaves of Byrsonima fagifolia Niedenzu (Malpighiaceae), a Brazilian plant used as an infusion to treat gastric disorders, was developed. The method was based on high-performance liquid chromatography coupled to electrospray negative ionisation multistage ion trap mass spectrometry (HPLC/ESI-ITMSn). The main ions in the ESI-ITMS spectra were attributed to a quinic acid core containing from one to five galloyl units. Quercetin derivatives containing one and two sugar moieties as well as galloyl esterification were also detected. These results indicated that HPLC/ESI-ITMSn is easily applicable to infusions of this plant and allows the rapid and direct identification of these compounds in crude plant extracts. Copyright (C) 2007 John Wiley & Sons, Ltd.

Preparative isolation of a novel flavonoid from an infusion of Byrsonima basiloba leaves by high-speed counter-current chromatography

A method for the isolation of three compounds from the infusion of leaves of Byrsonima basiloba A. Juss. by high-speed counter-current chromatography (HSCCC) was developed. This technique led to the separation of a novel compound, quercetin 3-O-alpha-L-rhamnopyranosyl-(1 -> 3)-O-[alpha-L-rhamnopyranosyl-(1 -> 6)]-beta-D-allopyranoside, and two known compounds quercetin3-O-(X-L-rhamnopyranosyl-(1 -> 6)-beta-D-galactopyranoside and (+)-catechin in 4 h with purities of over 92%. The structures of the compounds were determined by one- and two-dimensional NMR spectroscopy and HPLC.

In vitro allelopathic effects of extracts and amenthoflavone from Byrsonima crassa (Malpighiaceae)

Extracts and pure amenthoflavone isolated from Byrsonima crassa (Malpighiaceae), a shrub growing in the semi-arid region of Brazil Cerrado, were evaluated in vitro, at different doses, for their effects on tomato seed germination and subsequent growth of seedlings. A hydromethanolic extract showed general stimulatory effects. The EtOAc extract stimulated root elongation and root weight of tomato; shoot elongation was inhibited, while shoot weight was not altered. The pure amenthoflavone isolated from the plant, stimulated shoot elongation at concentrations ranging between 10(-4) M and 10(-6) M.

In situ and simultaneous nanostructural and spectroscopic studies of ZnO nanoparticle and Zn-HDS formations from hydrolysis of ethanolic zinc acetate solutions induced by water

The simultaneous formation of nanometer sized zinc oxide (ZnO), and acetate zinc hydroxide double salt (Zn-HDS) is described. These phases, obtained using the sol-gel synthesis route based on zinc acetate salt in alcoholic media, were identified by direct characterization of the reaction products in solution using complementary techniques: nephelometry, in situ Small-Angle X-ray Scattering (SAXS), UV-Vis spectroscopy and Extended X-ray Absorption Fine Structures (EXAFS). In particular, the hydrolytic pathway of ethanolic zinc acetate precursor solutions promoted by addition of water with the molar ratio N = [H2O]/[Zn2+] = 0.05 was investigated in this paper. The aim was to understand the formation mechanism of ZnO colloidal suspension and to reveal the factors responsible for the formation of Zn-HDS in the final precipitates. The growth mechanism of ZnO nanoparticles is based on primary particle (radius approximate to 1.5 nm) rotation inside the primary aggregate (radius < 3.5 nm) giving rise to an epitaxial attachment of particles and then subsequent coalescence. The growth of second ZnO aggregates is not associated with the Otswald ripening, and could be associated with changes in equilibrium between solute species induced by the superficial etching of Zn-HDS particles at the advanced stage of kinetic.

Structural behaviour of three-pile caps subjected to axial compressive loading

This work presents a comparative analysis about the behaviour of pile caps supported by 3 piles subjected to axial loading. Piles with 20 cm and 30 cm diameters were analysed. The main reinforcement was maintained in all the specimens, however, the arrangement of the secondary reinforcement varied. The main reinforcement consisted of steel bars connecting the piles. The secondary reinforcement was made up of: (a) bars going through the piles and through the projection of the column, (b) bars forming a network, and (c) vertical and horizontal stirrups. The main objective was the observation of the pile cap behaviour regarding the cracks and the modes of rupture. The real scale specimens were subjected to experimental tests until failure by rupture. Instruments were placed with the aim to obtain the displacement of the bases, the strains in the main and secondary reinforcement bars, in the compression struts, in the lower and upper nodal zones and in the sides of the caps. None of the caps reached failure by rupture with a load less than 1.12 times the theoretical load. The specimens ruptured due to the cracking of the compression strut and/or the yielding of the reinforcement bars in one direction.

Evolution of the viscoelastic properties of SnO2 colloidal suspensions during the sol-gel transition

This paper describes the effect of the concentration of electrolyte and pH on the kinetics of aggregation and gelation processes of SnO2 colloidal suspensions. Creep, creep-recovery, and oscillatory rheological experiments have been done in situ during aggregation and gelation. A phenomenological description of the structure of the colloidal system is given from the time evolution of rheological parameters. The dependence of the equilibrium steady-state shear compliance on the terminal region of clusters or aggregates seems to be a way to determine the beginning of interconnection of aggregates and the gel point. We propose that at this point the equilibrium steady-state compliance is a minimum. The steady-state viscosity determined from creep experiment can be fit with a power law with the extent of the transformation, giving critical exponent s = 0.7 ± 0.1. The value of the critical exponent Δ = 0.78 ± 0.05 was determined from oscillatory experiment. These results indicate that gelation of SnO2 colloidal suspension exhibits the typical scale expected from the scalar percolation theory. © 2000 Elsevier Science B.V. All rights reserved.

Optimization of neural classifiers based on bayesian decision boundaries and idle neurons pruning

In this article we describe a feature extraction algorithm for pattern classification based on Bayesian Decision Boundaries and Pruning techniques. The proposed method is capable of optimizing MLP neural classifiers by retaining those neurons in the hidden layer that realy contribute to correct classification. Also in this article we proposed a method which defines a plausible number of neurons in the hidden layer based on the stem-and-leaf graphics of training samples. Experimental investigation reveals the efficiency of the proposed method. © 2002 IEEE.

rDNA-RFLP identification of Candida species in immunocompromised and seriously diseased patients

PCR was used to amplify a targeted region of the ribosomal DNA of 76 Candida spp. isolates from immunocompromised and seriously diseased patients. Thirty-seven strains isolated from different anatomical sites of 11 patients infected with HIV (Vitória, ES, Brazil), 26 isolates from patients under treatment at Odilon Behrens Hospital and 13 isolates from skin and urine samples from São Marcos Clinical Analysis Laboratory (Belo Horizonte, Brazil) were scored. Fragments of rDNA were amplified using primer pairs ITS1-ITS4, for the amplification of ITS1 and ITS2 regions, including the gene for the 5.8s subunit. Amplification resulted in fragments ranging in size from 350 to 950 bp. Amplicons were digested with eight restriction enzymes. A pattern of species-specificity among the different medically important Candida species could be identified following restriction digestion of the PCR products. Candida albicans was the species most frequently observed, except for the group of newborns under treatment at the Odilon Behrens Hospital and for the isolates from the clinical analysis laboratory. C. parapsilosis was the species most frequently observed in these two groups.

Resídue de polpas de frutas desidratadas na alimentação de leitões em fase de creche

It was evaluated chemically and biologically the powdered fruits pulp residue, used in human food industry. In the digestibility study it was used 12 commercial hybrids barrows piglets, with initial weight 12.2 ± 1,6 kg, allotted in individual cages. The treatments were a basal and a test diet. In the test diet the fruits pulp residue replaced 30% of the basal dry matter. The following values were obtained: dry matter 89,54%, starch 71,1%, glucose 5.4%, fructose 2,2%, crude protein 5,33%, gross energy 3771 kcal/kg, apparent digestible dry matter 96,01%, digestible energy 3448 kcal/kg, metabolizable energy 3389 kcal/kg. By bromatologic results and metabolism study, the powdered fruits pulp residue was characterized as an alternative to be evaluated in piglet diets. In the performance assay 90 piglets with initial weight of 6,60 ± 0,76 kg were allotted in a randomized block design, with six replications and three animals per experimental unit. The treatments were levels of powdered fruits pulp residue (0. 25, 50, 75 and 100%) replacing the corn of the control diet. The studied phases were initial-1 (14 days), initial-2 (21 days) and total period. On the performance there was no difference between the studied inclusion levels. For meal diets, the fruits pulp residue can replace the corn.

Synthesis, characterization, and biological activity of a new palladium(II) complex with deoxyalliin

Synthesis, characterization, and biological activity of a new water-soluble Pd(II)-deoxyalliin (S-allyl-L-cysteine) complex are described in this article. Elemental and thermal analysis for the complex are consistent with the formula [Pd(C6H10NO2S)2]. 13C NMR, 1H NMR, and IR spectroscopy show coordination of the ligand to Pd(II) through S and N atoms in a square planar geometry. Final residue of the thermal treatment was identified as a mixture of PdO and metallic Pd. Antiproliferative assays using aqueous solutions of the complex against HeLa and TM5 tumor cells showed a pronounced activity of the complex even at low concentrations. After incubation for 24 h, the complex induced cytotoxic effect over HeLa cells when used at concentrations higher than 0.40 mmol/L. At lower concentrations, the complex was nontoxic, indicating its action is probably due to cell cycle arrest, rather than cell death. In agreement with these results, the flow cytometric analysis indicated that after incubation for 24 h at low concentrations of the complex cells are arrested in G0/G1. © 2005 NRC Canada.