965 resultados para Index reduction techniques
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The chromosomes of hylids Hypsiboas albopunctatus, H. raniceps, and H. crepitans from Brazil were analyzed with standard and differential staining techniques. The former species presented 2n = 22 and 2n = 23 karyotypes, the odd diploid number is due to the presence of an extra element interpreted as B chromosome. Although morphologically very similar to the small-sized chromosomes of the A complement, the B was promptly recognized, even under standard staining, on the basis of some characteristics that are usually attributed to this particular class of chromosomes. The two other species have 2n = 24, which is the chromosome number usually found in the species of Hypsiboas karyotyped so far. This means that 2n = 22 is a deviant diploid number, resulted from a structural rearrangement, altering the chromosome number of 2n = 24 to 2n = 22. Based on new chromosome data, some possibilities were evaluated for the origin of B chromosome in Hypsiboas albopunctatus, as well as the karyotypic evolution in the genus, leading to the reduction in the diploid number of 2n = 24 to 2n = 22.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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The oxidation of a reactive dye, Cibacron Blue F3GA, CB, (C.I. 61211), widely used in the textile industries to color natural fibers, was studied by electrochemical techniques. The oxidation on glassy carbon electrode occurs in two steps at 2.0 < pH < 10 involving one electron transfer each to the amine group leading to the imide derivative. Stable films of poly-L-lysine (PLL) in the presence of glutaraldehyde (GA) 97.5%:2.5% on glassy carbon electrode can be used to detect low levels of dye using its oxidation peak at +0.75V by voltammetry. Linear calibration graphs were obtained for the CB reactive dye, from 1.0 X 10(-6) to 1.0 X 10(-5) mol L-1 in B-R buffer, pH 2.0, using a pre-concentration off-line during 10 min. The detection limit (3 sigma/slope) was calculated to be 4.5 X 10(-8) mol L-1. Films of PLL can readily be applied for the determination of CB dye bearing aminoanthraquinone as chromophore and chlorotriazinyl as reactive group at concentrations at least 100 times lesser than using a glassy carbon electrode without modification. The method described was applied for the determination of CB dye in tap water and raw water collected from the municipal treatment plant with a recovery of 89.2% +/- 5.4 and 88.0% +/- 6.5, respectively. (c) 2005 Elsevier Ltd. All rights reserved.
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The electrochemical behaviour of tin in de-aerated sodium perchlorate was studied using potentiodynamic and potentiostatic techniques. Tin behaviour in sodium perchlorate has been complicated unexpectedly by the reduction of the perchlorate anion. It is shown that the reduction process takes place within a potential region comprising the negative side of the double layer region and the positive side of the hydrogen region (-0.7 less than or equal to E less than or equal to -1.3 V). The presence of oxide on the electrode surface favours the reduction reaction, which may occur in two steps: the formation of basic tin(II) chloride followed by its reduction, producing chloride.
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In this paper we present and demonstrate a technique that allows simultaneous and independent measurement of small changes in the refractive index and the absorption coefficient produced in photosensitive materials during holographic exposure. The technique is based on the synchronous detection of two-wave mixing signals in both directions of the transmitted interfering beams. By processing both signals it is possible to separate the diffraction contributions of the refractive index from the absorption coefficient and simultaneously stabilize the incident fringe pattern. The demonstration of this technique is undertaken by following the temporal evolution of the phase and amplitude modulations in photoresist films. To check the ability of the technique to perform numeric evaluations, for a positive photoresist the changes in the optical constants were measured and compared with those obtained using independent methods.
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Protein-energy malnutrition is a syndrome in which anaemia together with multivitamin and mineral deficiency may be present. The pathophysiological mechanisms involved have not, however, yet been completely elucidated. The aim of the present study was to evaluate the pathophysiological processes that occur in this anaemia in animals that were submitted to protein-energy malnutrition, in particular with respect to Fe concentration and the proliferative activity of haemopoietic cells. For this, histological, histochemical, cell culture and immunophenotyping techniques were used. Two-month-old male Swiss mice were submitted to protein-energy malnutrition with a low-protein diet (20g/kg) compared with control diet (400 g/kg). When the experimental group had attained a 20% loss of their original body weight, the animals from both groups received, intravenously, 20IU erythropoietin every other day for 14 d. Malnourished animals showed a decrease in red blood cells, Hb concentration and reticulocytopenia, as well as severe bone marrow and splenic atrophy. The results for serum Fe, total Fe-binding capacity, transferrin and erythropoietin in malnourished animals were no different from those of the control animals. Fe reserves in the spleen, liver and bone marrow were found to be greater in the malnourished animals. The mixed colony-forming unit assays revealed a smaller production of granulocyte-macrophage colony-forming units, erythroid burst-forming units, erythroid colony-forming units and CD45, CD117, CD119 and CD71 expression in the bone marrow and spleen cells of malnourished animals. These findings suggest that, in this protein-energy malnutrition model, anaemia is not caused by Fe deficiency or erythropoietin deficiency, but is a result of ineffective erythropoiesis.
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The paper evaluates the applicability of products of remote sensing in studies related to the structural conditionings of slope stability in saprolites, usually conducted through field surveys. In this article we use a regional approach concentrating on an area of lane duplication of a major highway. In that area, resistance reduction to stress and the low cohesions of muscovite saprolites - schists and gneiss which are associated to geological discontinuities, all result in inumerous instabilities. The joints and foliations were extracted from satellite images as well as aerial photographs. Following that, the study area was divided into various sectors based on the directions and dips of the foliation. Different relationships between the structures and the slopes were analyzed in order to indicate the most feasible type of slope failure in each sector of analysis. The aim of the study is to subsidize further detailed future research.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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This study was carried out to describe the clinical characteristics of natural infection caused by Trypanosoma cruzi in dogs that reside in a rural area of Mato Grosso do Sul State, Brazil. Conventional and nonconventional diagnostic methods were used for screening T. cruzi infection in 75 dogs that lived in the area. Cardiovascular tests and biochemical examination of sera were also performed in four confirmed positive dogs. The following techniques were employed: indirect immunofluorescence test (IFAT), enzyme-linked immunosorbent assay with T. cruzi epimastigote antigens (EAE-ELISA) and enzyme-linked immunosorbent assay with T. cruzi excreted-secreted trypomastigote antigens (TESA-ELISA) with antibodies detected in 45.33% (n = 34), 24.0% (n = 18) and 12.0% (n = 9) of the dogs, respectively. The current prevalence of the infection was confirmed as 10.7% (n = 8) by immunoblotting test with T. cruzi excreted-secreted antigens (TESA-blot). The test that showed the best concordance index (Kappa; 0.93), sensitivity (100%) and specificity (98.5%) was TESA-ELISA, that when associated with IFAT had the same results as those obtained by TESA-blot (10.7%). Three out of the four chagasic animals showed enlarged cardiac silhouette on X-ray and an increase of the P-wave duration and QRS complex in electrocardiogram. Two dogs presented conduction disturbances, right bundle branch block in one dog and first-degree atrioventricular block and sinus arrest in another. The ecodopplercardiography presented left-ventricular-wall thickness increased during diastole, decrease of the shortening fraction and inversion in the speed peaks of the E and A waves, indicating the presence of systolic and diastolic disorders. The four animals showed enzymatic activities of creatine kinase (221-404 U/L), MB fraction of creatine kinase (189-304 U/L), elevated total proteins (7.6-10.2 g/dL) and total globulins (4.6-7.7g/dL) and reduction of albumin/globulin ratio, which suggested a myocardial injury and continuous antigenic stimulus.
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Turquoise blue 15 (AT15) is a reactive dye widely used in the textile industry to color natural fibers. The presence of these dyes in effluent and industrial wastewater is of considerable interest due ecotoxicological and environmental problems. The electrochemical reduction of this dye has been investigated in aqueous solution using cyclic voltammetry, controlled potential electrolysis and cathodic stripping voltammetry. Optimum conditions for dye discoloration by controlled potential electrolysis use an alkaline medium. Using cathodic stripping voltammetry a linear calibration graph was obtained from 5.00×10-8 mol L-1 to 1.00×10 -6 mol L-1 of AT15 at pH 4.0, using accumulation times of 180 and 240 s and an accumulation potential of 0.0 V. The proposed method was applied in direct determination of the dye in tap water and in textile industry effluent.
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In this paper it is presented recent developments in the heterodyne detection holographic techniques for studding photosensitive materials. The actual state of the technique allows simultaneous and independent measurement of the refractive index and of the absorption coefficient changes in photosensitive materials and their use to self-stabilize the fringe pattern. The modeling of the measured signal together with the fringe stabilization allow the long term-fitting of the optical properties and the study the photosensitive materials close to the saturation.
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The geographic area of the present study corresponds to the basin of the Itiquira river high course (Figure 1), in the portion that extends from the tributaries of its source, in the east of the plateau Correntes/Itiquira, in the neighbourhoods the city of Alto Garç as, to the scarp of the São Jerônimo mountain range, toward the west of Itiquira, in the state of Mato Grosso, totalizing 5,361 km 2. The area is placed in the eastern part of the Alto Paraguai basin, in the western portion of the Paraná Sedimentary Basin plateau. Through GIS techniques, it was possible to asses total soil losses from the Itiquira river basin, considering the years of 1966, 1985 and 1996, being based on the Universal Soil Loss Equation. Thus, in 1966 the basin lost 201,546.94 ton of soil, with an average loss of 0.37 ton/ha/year. Considering that the total area of the Itiquira river basin is of 536,100 ha, while in 1985 the soil losses had passed to 1,760,833.40 ton, with an increase of approximately 8.5 times. The average of soil losses in 1985 was of 3.28 ton/ha/year. In 1996 the basin lost 1,662,043.24 ton, with a reduction of only 9.4% in relation to 1985 but, in relation the 1966, the increase continued in the order of 8 times. The average losses per hectare in this year was in the order of 3.10 ton/ha/year (Chart 1). The map of potential of the laminar erosion for 1966 (Figure 3), shows to the highest values in small areas, situated in the northeast of the area, in Alto Garças, with values between 10 the 20 ton/ha/year and some spots in sources of the Itiquira and Ariranha rivers, with values between 1 the 5 ton/ha/year. In a general way, however, the area presents low soil loss for laminar erosion in this year, with inferior values to 1 ton/ha/year. The higher class of erosion, over 10 ton/ha/year, occupied 2,947 ha in 1966. In the year of 1985 (Figure 4), the erosive process spread over the entire studied area, and the class of erosion over of 10 ton/ha/year, already started to occupy 78,437 ha, implying an increase of approximately 27 times in 19 years. A strong increment in the erosive process was noticed in the western part of the area, to along the BR-163 road, exactly where great areas of natural vegetation (open pasture) had been transformed in culture and pasture areas. In the north-eastern part of the area it was also noticed an increment in the erosive process in agreement with the increase of culture areas and reduction of the natural areas, but it was not of so intense form as in the western portion of the area. In the year of 1996 (Figure 5), the class of erosion over of 10 ton/ha/year had diminished for a total of 53.499 ha noticing a retraction of the erosive process in the western part of the area, alongside the BR-163 road. On the other hand, it occurred a strong increment in the northern part of the area, in the neighbourhoods of the city of Alto Garças, alongside the BR-364 road and part of the MT-040 road. In a general way, in the outskirts of the city of Itiquira, in the central part of the area, it was verified an increase of the amount of zones with erosion between 0-1 ton/ha/year, passing to the immediately superior class, of 1-3 ton/ha/year; scarce data of hydrosedimentology in the UHE Itiquira (1999), shows good agreement with the values gotten for the EUPS (Chart 2). Based on the hydric classification proposal for FAO (1967) (Chart 3), it is noticed that areas with high degree of erosion (> 50) in the analysed area are very restricted, occupying 493 ha in 1985 and 332 ha in 1996 (Chart 4). In 1996 appeared as isolated spots in the north of Itiquira and Alto Garças, however beyond limits of the Itiquira river basin. These areas require special cares in its use as agricultural areas. Aiming at identifying and indicating the areas of potential risk of erosion and that need implementation of conservation practices, it was elaborated the map of limit of tolerance to the soil losses. In 1966 (Figure 6), areas with soil losses over of the tolerable were restricted to small spots located in the eastern part of the area, occupying 0.43% of the total of the area; already in 1985 (Figure 7), this percentage passed to 5.86%, spreading for all the area; in 1996 (Figure 8) it is observed a fast reduction of the areas with soil losses over of the tolerance limit, passing 5.43% of the total of the area. All the areas with losses over of the tolerable value must be considered as risk areas and were done in these areas studies for implementation of conservation practices.
Electrochemical reduction and voltammetric determination of diloxanide furoate in non-aqueous medium
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The electrochemical reduction of diloxanide furoate (DF) in acetonitrile on glassy carbon electrode was studied in this work. It was observed that DF is reduced after a reversible one-electron transfer followed by an irreversible chemical reaction, diagnosed as C-Cl bond cleavage. Its reduction was followed by linear (LSV), differential pulse (DPV) and square wave voltammetry (SWV). Analytical curves were obtained for DF determination using all the investigated voltammetric techniques. For LSV was obtained a linear range (LR) from 5.0 × 10-4 to 1.0 × 10-2 mol L-1, with detection limit (DL) of 1.5 × 10-4 mol L-1 and sensitivity (S) of 2.1 × 104 μA mol-1 L. The analytical parameters obtained by DPV were: LR = 5.0 × 10-4 to 2.2 × 10-3 mol L-1, DL = 7.8 × 10-5 mol L-1, S = 3.7 × 104 μA mol-1 L. For SWV were obtained a LR = 7.5 × 10-6 to 1.2 × 10 -3 mol L-1, DL = 5.5 × 10-6 mol L -1 and S = 2.8 × 105 μA mol-1 L. Thus, the SWV was the most sensible technique, which can be used for DF determination at low concentration levels. Statistics methods were used to evaluate the analytical procedure, where recovery around to 100% was obtained for all voltammetric techniques. Relative standard deviations were lower than 5.0% (N=5). The obtained t values evaluating all the three voltammetric methods were less than the tabulated ones, indicating that there are no evidences of systematic error. ©2005 Sociedade Brasileira de Química.
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The formation of sulfated zirconia films from a sol-gel derived aqueous suspension is subjected to double-optical monitoring during batch dip coating. Interpretation of interferometric patterns, previously obscured by a variable refractive index, is now made possible by addition of its direct measurement by a polarimetric technique in real time. Significant sensitivity of the resulting physical thickness and refractive index curves (uncertainties of ±7 nm and ±0.005, respectively) to temporal film evolution is shown under different withdrawal speeds. As a first contribution to quantitative understanding of temporal film formation with varying nanostructure during dip coating, detailed analysis is directed to the stage of the process dominated by mass drainage, whose simple modeling with temporal t-1/2 dependence is verified experimentally. © 2006 Elsevier B.V. All rights reserved.