948 resultados para Successive Overrelaxation method with 1 parameter


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During 90 days 243 finishing feedlot animals from two genetic groups, were weighed every 28 days in a randomized experimental procedure in a 2 x 3 factorial arrangement, with two breeds - Nelore (Nel) and Canchim (Can) - and three treatments: water (A), cane stillage + magnesium oxide (V) and cane stillage + magnesium oxide + sodium bicarbonate (V + B). The diet for all treatments was composed of 70% of corn silage and 30% of chopped sugar cane ad libitum plus 1 kg of ground corn and 1,5 kg of soluble yeast per animal. Results showed higher weight gain (P < 0,01) of the Can group relation to those of Nel, having respectively 1,35 and 1,22 kg/head/day. Both Can and Nel groups showed higher weight gain (P <.01) when fed with V + B, with 1,44 and 1,32 kg/head/day respectively when comparing to the other diets: Can (A) = 1,30; Can (V) = 1,31; Nel (A) = 1,16 and Nel (V) = 1,20 kg/head/day. The diet using V + B has also showed a tendency (.05

10) of better food conversion thus showing positive effect of cane stillage when associated to the neutralizing compounds of the ruminal pH.

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Highly (100) oriented Pb0.8Ba0.2TiO3/LaNiO3 structures were grown on LaAlO3(100) substrates by using a wet, soft chemical method and crystallized by the microwave oven technique. The Au/PBT/LaNiO3/LaAlO3 capacitor shows a hysteresis loop with remnant polarization, P-r, of 15 muC/cm(2), and coercive field, E-c, of 47 kV/cm at an applied voltage of 3 V, along with a dielectric constant over 1800. Atomic force microscopy showed that Pb0.8Ba0.2TiO3 is composed of large grains about 300 nm. The experimental results demonstrated that the microwave preparation is rapid, clean, and energy efficient. Therefore, we demonstrated that the combination of the soft chemical method with the microwave process is a promising technique to grow highly oriented thin films with excellent dielectric and ferroelectric properties, which can be used in various integrated device applications. (C) 2004 American Institute of Physics.

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The objective of this study was to determine intraocular pressure (IOP) and cardiac changes in normocapnic dogs maintained under controlled ventilation and anesthetized using sevoflurane or desflurane. Sixteen healthy adult mixed-breed dogs, seven males and nine females, weighing 10-15 kg were used. The dogs were randomly assigned to one of two groups composed of eight animals anesthetized with sevoflurane (SEVO) or desflurane (DESF). In both groups, anesthesia was induced with propofol (10 mg/kg), and neuromuscular blockade was achieved with rocuronium (0.6 mg/kg/h IV). No premedication was given. Ventilation was adjusted to maintain end-tidal carbon dioxide partial pressure at 35 mmHg. Anesthesia was maintained with 1.5 minimum alveolar concentration (MAC) of sevoflurane or desflurane. In both groups IOP was measured by applanation tonometry (Tono-Pen) before induction of anesthesia. IOP, mean arterial pressure (MAP), heart rate (HR), cardiac index (CI) and central venous pressure (CVP) were also measured 45 min after the beginning of inhalant anesthesia and then every 20 min for 60 min. A one-way repeated measures ANOVA was used to compare data within the same group and Student's t-test was used to assess differences between groups. P < 0.05 was considered statistically significant. Measurements showed normal IOP values in both groups, even though IOP increased significantly from baseline during the use of desflurane. IOP did not differ between groups. CI in the desflurane group was significantly greater than in the sevoflurane group. Sevoflurane and desflurane have no clinically significant effects on IOP, MAP, HR, CI or VCP in the dog.

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Undoped and/or doped with 1 mol% of Co2+ Mg2TiO4 and Mg2SnO4 powders were synthesized by the polymeric precursor method. The influence of the network former (Sn4+ or Ti4+) on the thermal, structural and optical properties was investigated. The recorded mass losses are due to the escape of water and adsorbed gases and to the elimination of the organic matter. Mg2TiO4 crystallizes at lower temperatures and also presents more ordered structure with a smaller unit call and having more intense green color than Mg2SnO4 has.

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An automated system with a C-18 bonded silica gel packed minicolumn is proposed for spectrophotometric detection of arsenic using flow-injection hydride generation following sorbent extraction preconcentration. Complexes formed between arsenic(III) and ammonium diethyl dithiophosphate (ADDP) are retained on a C-18 sorbent. The eluted As-DDP complexes are merged with a 1.5% (w/v) NaBH4 and the resulting solution is thereafter injected into the hydride generator/gas-liquid separator. The arsine generated is carried out by a stream of N-2 and trapped in an alkaline iodine solution in which the analyte is determined by the arsenomolybdenum blue method. With preconcentration time of 120 s, calibration in the 5.00-50.0 mu g As l(-1) range and sampling rate of about 20 samples h(-1) are achieved, corresponding to 36 mg ADDP plus 36 mg ammonium heptamolybdate plus 7 mg hydrazine sulfate plus 0.7 mg stannous chloride and about 7 mi sample consumed per determination. The detection limit is 0.06 mu g l(-1) and the relative standard deviation (n = 12) for a typical 17.0 mu g As l(-1) sample is ca. 6%. The accuracy was checked for arsenic determination in plant materials from the NIST (1572 citrus leaves; 1573 tomato leaves) and the results were in agreement with the certified values at 95% confidence level. Good recoveries (94-104%) of spiked tap waters, sugars and synthetic mixtures of trivalent and pentavalent arsenic were also found. (C) 1999 Elsevier B.V. B.V. All rights reserved.

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The partial oxalate method, with the columbite route, associated with the Pechini method, was used to obtain a very fine ceramic powder at low temperature. Using this route it was possible to obtain a very reactive powder and to synthesize a lead magnesium niobate (PMN) powder with up to 100% of perovskite phase at a lower temperatures than the PbO melting point. The influence of the BaTiO3 and PbTiO3 seeds in the phase formation, along with time and temperature during the PMN calcination, was also investigated. The amount of 2% of BaTiO3 seeds promoted PMN powder formation with 100% of perovskite phase and a very narrow particle size distribution. (C) 2001 Elsevier B.V. Ltd and Techna S.r.l. All rights reserved.

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Bark extracts of Stryphnodendron adstringens (Mart) Coville a Leguminosae species, well known in Brazil as barbatimao, are popularly used as healing agent. The objective of this work was to determine the genetic diversity of S. adstringens populations and to correlate genetic distances to the production of tannins. S. adstringens accessions from populations found in Cerrado regions in the states of Goias, Minas Gerais and São Paulo were analyzed using the AFLP (Amplified Fragment Length Polymorphism) technique. A total of 236 polymorphic bands were scored and higher proportion of genetic diversity was found inter populations (70.9%), rather than intra populations (29.1%). F-ST value was found to be significantly greater than zero (0.2906), demonstrating the complex genetic structure of S. adstringens populations. Accessions collected in Cristalina, GO, showed higher percentage of polymorphic loci (87.3%) and the highest genetic diversity. The lowest genetic variability was detected among accessions from the population growing in Caldas Novas, GO. The genetic distance among populations was estimated using the Unweighted Pair Group Method with Arithmetic Mean (UPGMA), which grouped populations into 3 clusters. Moreover, chemotypes with tannin concentration above 40% showed higher genetic similarity. AFLP analysis proved to be an efficient gene mapping technique to determine the genetic diversity among remaining populations of S. adstringens. Obtained results may be employed to implement further strategies for the conservation of this medicinal plant. (C) 2011 Elsevier Ltd. All rights reserved.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The present study is concerned with the structural and electronic properties of the TiO2/SnO2/TiO2 and SnO2/TiO2/SnO2 composite systems. Periodic quantum mechanical method with density functional theory at the B3LYP level has been carried out. Relaxed surface energies, structural characteristics and electronic properties of the (I 10), (0 10), (10 1) and (00) low-index rutile surfaces for TiO2/SnO2/TiO2 and SnO2/TiO2/SnO2 models are studied. For, comparison purposes, the bare rutile TiO2 and SnO2 structures are also analyzed and compared with previous theoretical and experimental data. The calculated surface energy for both rutile TiO2 and SnO2 surfaces follows the sequence (110) < (010) < (101) < (001) and the energy increases as (010) < (101) < (110) < (001) and (010) approximate to (110) < (101) < (001) for SnO2/TiO2/SnO2 and TiO2/SnO2/TiO2 composite systems, respectively. SnO2/TiO2/SnO2 presents larger values of surface energy than the individual SnO2 and TiO2 metal oxides and the TiO2/SnO2/TiO2 system renders surface energy values of the same order that the TiO2 and lower than the SnO2. An analysis of the electronic structure of the TiO2/SnO2/TiO2 and SnO2/TiO2/SnO2 systems shows that the main characteristics of the upper part of the valence bands for all the studied surfaces are dominated by the external layers, i.e., by the TiO2 and the SnO2, respectively, and the topology of the lower part of the conduction bands looks like the core layers. There is an energy stabilization of both valence band top and conduction band bottom for (110) and (010) surfaces of the SnO2/TiO2/SnO2 composite system in relation to their core TiO2, whereas an opposite trend is found for the same surfaces of the TiO2/SnO2/TiO2 composite system in relation to the bare SnO2. The present theoretical results may explain the growth of TiO2@SnO2 bimorph composite nanotape.

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SrSnO3 was synthesized by the polymeric precursor method with elimination of carbon in oxygen atmosphere at 250 A degrees C for 24 h. The powder precursors were characterized by TG/DTA and high temperature X-ray diffraction (HTXRD). After calcination at 500, 600 and 700 A degrees C for 2 h, samples were evaluated by X-ray diffraction (XRD), infrared spectroscopy (IR) and Rietveld refinement of the XRD patterns for samples calcined at 900, 1,000 and 1,100 A degrees C. During thermal treatment of the powder precursor ester combustion was followed by carbonate decomposition and perovskite crystallization. No phase transition was observed as usually presented in literature for SrSnO3 that had only a rearrangement of SnO6 polyhedra.

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

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Chagas disease is a serious health problem in Latin America. Hidroxymethylnitrofurazone (NFOH) is a nitrofurazone prodrug more active than nitrofurazone against Trypanosoma cruzi. However, NFOH presents low aqueous solubility, high photodecomposition and high toxicity. The present work is focused on the characterization of an inclusion complex of NFOH in 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CD). The complexation with HP-beta-CD was investigated using reversed-phase liquid chromatography, solubility isotherms and nuclear magnetic resonance. The retention behavior was analyzed on a reversed-phase C-18 column, using acetonitrile-water (20/80, v/v) as the mobile phase, in which HP-beta-CD was incorporated as a mobile phase additive. The decrease in the retention times with increasing concentrations of HP-beta-CD enables the determination of the apparent stability constant of the complex (K = 6.2 +/- 0.3 M-1) by HPLC. The solubility isotherm was studied and the value for the apparent stability constant (K = 7.9 +/- 0.2 M-1) was calculated. The application of continuous variation method indicated the presence of a complex with 1:1 NFOH:HP-beta-CD stoichiometry. The photostability study showed that the formation of an inclusion complex had a destabilizing effect on the photodecomposition of NFOH when compared to that of the "free" molecule in solution. The mobility investigation (by NMR longitudinal relaxation time) gives information about the complexation of NFOH with HP-beta-CD. In preliminary toxicity studies, cell viability tests revealed that inclusion complexes were able to decrease the toxic effect (p < 0.01) caused by NFOH. (c) 2008 Elsevier B.V. All rights reserved.

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A comparative study of nine assay methods for dextransucrase and related enzymes has been made. A relatively widespread method for the reaction of dextransucrase with sucrose is the measurement of the reducing value of D-fructose by alkaline 3,5-dinitrosalicylate (DNS) and thereby the amount of D-glucose incorporated into dextran. Another method is the reaction with C-14-sucrose with the addition of an aliquot to Whatman 3MM paper squares that are washed three times with methanol to remove C-14-D-fructose and unreacted C-14-sucrose, followed by counting of C-14-dextran on the paper by liquid scintillation counting (LSC). It is shown that both methods give erroneous results. The DNS reducing value method gives extremely high values due to over-oxidation of both D-fructose and dextran, and the C-14-paper square method gives significantly low values due to the removal of some of the C-14-dextran from the paper by methanol washes. In the present study, we have examined nine methods and find two that give values that are identical and are an accurate measurement of the dextransucrase reaction. They are (1) a C-14-sucrose/dextransucrase digest in which dextran is precipitated three times with three volumes of ethanol, dissolved in water, and added to paper and counted in a toluene cocktail by LSC: and (2) precipitation of dextran three times with three volumes of ethanol from a sucrose/dextransucrase digest, dried, and weighed. Four reducing value methods were examined to measure the amount of D-fructose. Three of the four (two DNS methods, one with both dextran and D-fructose and the other with only D-fructose, and the ferricyanide/arsenomolybdate method with is-fructose) gave extremely high values due to over-oxidation of D-fructose, D-glucose, leucrose, and dextran. (C) 2011 Elsevier Ltd. All rights reserved.

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The unique carbohydrate-binding property of lectins makes them invaluable tools in biomedical research. Here, we report the purification, partial primary structure, carbohydrate affinity characterization, crystallization, and preliminary X-ray diffraction analysis of a lactose-specific lectin from Cymbosema roseum seeds (CRLII). Isolation and purification of CRLII was performed by a single step using a Sepharose-4B-lactose affinity chromatography column. The carbohydrate affinity characterization was carried using assays for hemagglutination activity and inhibition. CRLII showed hemagglutinating activity toward rabbit erythrocytes. O-glycoproteins from mucine mucopolysaccharides showed the most potent inhibition capacity at a minimum concentration of 1.2 A mu g mL(-1). Protein sequencing by mass spectrometry was obtained by the digestion of CRLII with trypsin, Glu-C, and AspN. CRLII partial protein sequence exhibits 46% similarity with the ConA-like alpha chain precursor. Suitable protein crystals were obtained with the hanging-drop vapor-diffusion method with 8% ethylene glycol, 0.1 M Tris-HCl pH 8.5, and 11% PEG 8,000. The monoclinic crystals belong to space group P2(1) with unit cell parameters a = 49.4, b = 89.6, and c = 100.8 A....