Metodologia para determinar parâmetros petrofísicos de corte em um campo de petróleo: o caso Socororo, bacia do Oriente, Venezuela

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Contribuições das técnicas projetivas gráficas para a compreensão da personalidade de andarilhos de estrada

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

Duffy blood group gene polymorphisms among malaria vivax patients in four areas of the Brazilian Amazon region

Background: Duffy blood group polymorphisms are important in areas where Plasmodium vivax predominates, because this molecule acts as a receptor for this protozoan. In the present study, Duffy blood group genotyping in P. vivax malaria patients from four different Brazilian endemic areas is reported, exploring significant associations between blood group variants and susceptibility or resistance to malaria.Methods: the P. vivax identification was determined by non-genotypic and genotypic screening tests. The Duffy blood group was genotyped by PCR/RFLP in 330 blood donors and 312 malaria patients from four Brazilian Amazon areas. In order to assess the variables significance and to obtain independence among the proportions, the Fisher's exact test was used.Results: the data show a high frequency of the FYA/FYB genotype, followed by FYB/FYB, FYA/FYA, FYA/FYB-33 and FYB/FYB-33. Low frequencies were detected for the FYA/FY(X), FYB/FY(X), FYX/FY(X) and FYB-33/FYB-33 genotypes. Negative Duffy genotype (FYB-33/FYB-33) was found in both groups: individuals infected and non-infected (blood donors). No individual carried the FY(X)/FYB-33 genotype. Some of the Duffy genotypes frequencies showed significant differences between donors and malaria patients.Conclusion: the obtained data suggest that individuals with the FYA/FYB genotype have higher susceptibility to malaria. The presence of the FYB-33 allele may be a selective advantage in the population, reducing the rate of infection by P. vivax in this region. Additional efforts may contribute to better elucidate the physiopathologic differences in this parasite/host relationship in regions endemic for P. vivax malaria, in particular the Brazilian Amazon region.

Change in the ascorbic-acid content of acerolas (Malpighia-glabra L) as function of harvest maturation degree and storage-temperature

The content of ascorbic acid was assayed in acerolas harvested in three phases of maturation: green-yellow fruits (I); light red (II) and wine-coloured (III). Phase I and Phase II fruit were packed in aluminium sheets and stoppered flasks and stored in freezer (-10o.C) and in refrigerator (8o.C). Samples of 8 fruits from each experimental condiction were analysed for ascorbic acid determination by 2-chlorophenol indophenol discolouration method. The averages of 1.393,5 mg./100g. for Phase I sample, 1024,9 for Phase II and 756,5 for Phase III fruits, showed a statistically significative linear decreasing of the ascorbic acid content related with the maturation extent Phase I samples stored in freezing showed statitically significative decreasing of that vitamin at 408 hours of storage in both: aluminium sheet and stoppered flask package; in chilling temperature there was significative reduction of ascorbic acid content after 240 and 312 hours, respectively, for fruits packed in aluminium sheet and stopped flasks. Phase Il samples showed significative lost at 72 hours of storage when maintained in freezing temperature either, in aluminium sheet or in stoppered flasks: When stored in chilling temperature showed progressive lost of ascorbic acid in all measuring periods in every package. After 144 hours suffered deterioration suggested by colour changes.

DEVELOPMENT OF A CHEMICALLY MODIFIED ELECTRODE BASED ON CARBON PASTE AND FUNCTIONALIZED SILICA-GEL FOR PRECONCENTRATION AND VOLTAMMETRIC DETERMINATION OF MERCURY(II)

A mercury-sensitive chemically modified electrode (CME) based on modified silica gel-containing carbon paste was developed. The functional group attached to the silica gel surface was 3-(2-thiobenzimidazolyl)propyl, which is able to complex mercury ions. This electrode was applied to the determination of mercury(II) ions in aqueous solution. The mercury was chemically preconcentrated on the CME prior to voltammetric determination by anodic stripping in the differential-pulse mode. A calibration graph covering the concentration range from 0.08 to 2 mg l-1 was constructed. The precision for six determinations of 0.122 and 0.312 mg l-1 Hg(II) was 3.2 and 2.9% (relative standard deviation), respectively. The detection limit for a 5-min preconcentration period was 0.013 mg l-1. A study for foreign ions was also made.

Spin reversal and magnetization jumps in ErMexMn1-xO3 perovskites (Me = Ni, Co)

The erbium-based manganite ErMnO3 has been partially substituted at the manganese site by the transition-metal elements Ni and Co. The perovskite orthorhombic structure is found from x(Ni) = 0.2-0.5 in the nickel-based solid solution ErNixMn1-xO3, while it can be extended up to x(Co) = 0.7 in the case of cobalt, provided that the synthesis is performed under oxygenation conditions to favor the presence of Co3+. Presence of different magnetic entities (i.e., Er3+, Ni2+, Co2+, Co3+, Mn3+, and Mn4+) leads to quite unusual magnetic properties, characterized by the coexistence of antiferromagnetic and ferromagnetic interactions. In ErNixMn1-xO3, a critical concentration x(crit)(Ni) = 1/3 separates two regimes: spin-canted AF interactions predominate at x < x(crit), while the ferromagnetic behavior is enhanced for x > x(crit). Spin reversal phenomena are present both in the nickel- and cobalt-based compounds. A phenomenological model based on two interacting sublattices, coupled by an antiferromagnetic exchange interaction, explains the inversion of the overall magnetic moment at low temperatures. In this model, the ferromagnetic transition-metal lattice, which orders at T-c, creates a strong local field at the erbium site, polarizing the Er moments in a direction opposite to the applied field. At low temperatures, when the contribution of the paramagnetic erbium sublattice, which varies as T-1, gets larger than the ferromagnetic contribution, the total magnetic moment changes its sign, leading to an overall ferrimagnetic state. The half-substituted compound ErCo0.50Mn0.50O3 was studied in detail, since the magnetization loops present two well-identified anomalies: an intersection of the magnetization branches at low fields, and magnetization jumps at high fields. The influence of the oxidizing conditions was studied in other compositions close to the 50/50 = Mn/Co substitution rate. These anomalies are clearly connected to the spin inversion phenomena and to the simultaneous presence of Co2+ and Co3+ magnetic moments. Dynamical aspects should be considered to well identify the high-field anomaly, since it depends on the magnetic field sweep rate. (C) 2006 Elsevier B.V. All rights reserved.

Electronic correlations for a two-level dimer: dynamical susceptibilities

The exact solution for the full electronic Hamiltonian for a two-level dimer is obtained. The parameter constellation (20) is reparametrized via orthogonal Slater atomic orbitals, yielding a three-parameter model. With the dimer embedded in a thermal bath, several temperature-dependent dynamical susceptibilities are computed. (C) 2002 Elsevier B.V. B.V. All rights reserved.

Effects of acepromazine on the cardiovascular actions of dopamine in anesthetized dogs

To evaluate the effects of acepromazine maleate on the cardiovascular changes induced by dopamine in isoflurane-anesthetized dogs.Prospective, randomized cross-over experimental design.Six healthy adult spayed female dogs weighing 16.4 +/- 3.5 kg (mean +/- SD).Each dog received two treatments, at least 1 week apart. Acepromazine (0.03 mg kg(-1), IV) was administered 15 minutes before anesthesia was induced with propofol (7 mg kg(-1), IV) and maintained with isoflurane (1.8% end-tidal). Acepromazine was not administered in the control treatment. Baseline cardiopulmonary parameters were measured 90 minutes after induction. Thereafter, dopamine was administered intravenously at 5, 10, and 15 mu g kg(-1) minute(-1), with each infusion rate lasting 30 minutes. Cardiopulmonary data were obtained at the end of each infusion rate.Dopamine induced dose-related increases in cardiac index (CI), stroke index, arterial blood pressure, mean pulmonary arterial pressure, oxygen delivery index (DO2I) and oxygen consumption index. In the control treatment, systemic vascular resistance index (SVRI) decreased during administration of 5 and 10 mu g kg(-1) minute(-1) of dopamine and returned to baseline with the highest dose (15 mu g kg (-1) minute(-1)). After acepromazine treatment, SVRI decreased from baseline during dopamine administration, regardless of the infusion rate, and this resulted in a smaller increase in blood pressure at 15 mu g kg (-1) minute(-1). During dopamine infusion hemoglobin concentrations were lower following acepromazine and this contributed to significantly lower arterial O-2 content.Acepromazine prevented the return in SVRI to baseline and reduced the magnitude of the increase in arterial pressure induced by higher doses of dopamine. However, reduced SRVI associated with lower doses of dopamine and the ability of dopamine to increase CI and DO2I were not modified by acepromazine premedication.Previous acepromazine administration reduces the efficacy of dopamine as a vasopressor agent in isoflurane anesthetized dogs. Other beneficial effects of dopamine such as increased CO are not modified by acepromazine.

THE CATHODIC CLEAVAGE OF THE NITROBENZENESULFONYL GROUP FROM ALIPHATIC-AMINES IN N,N-DIMETHYLFORMAMIDE

The reduction of benzenesulfonyl derivatives of n-butylamine and N,N-di-n-butylamine with nitro substituents at the 2, 3 and 4 positions of the phenyl ring in N,N-dimethylformamide is reported. The N,N-di-n-butyl-4- and N-n-butyl-2-nitrobenzenesulfonamides are reduced in two cathodic steps. The first one, at about -0.90 V vs. SCE, a reversible one-electron process, gives a stable anion radical. The second reduction step at -1.70 V vs. SCE leads to cleavage of the S-N bond in good yields (> 70%). It is shown that the reduction of the N-n-butyl-3- and N-n-butyl-4-nitrobenzenesulfonamide is different, with three reduction steps. The first reduction step occurs with the formation of an unstable anion radical, which decomposes via N-H bond cleavage. The reduction of this sulfonamide anion occurs at -1.16 V vs. SCE and the third cathodic step arises at -1.70 V vs. SCE when the remaining radical anion is reduced to its dianion. The S-N bond cleavage is rapid but is always a minor process. The mechanisms of the reduction are discussed.

Identification of bradykinins in solitary wasp venoms

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

Influence of Zn2+ co-doping ion on Eu3+-O2- associate luminescence in Sr2SiO4

This work reports on the study about the luminescence behavior of Eu3+-O2- associates in Sr2SiO4 doped with Eu3+, or simultaneously doped with Eu3+ and Zn2+ ions, where the Zn2+ doping ion acts as a charge compensating agent. Both Sr2SiO4:Eu3+ and Sr2SiO4:Eu3+,Zn2+ emission spectra show two types D-5(0)-->F-7(0) type transitions, one type related to Eu3+ in the Sr2+ Site, at 577 and 580 nm and the other one related to Eu3+-O2- associates, at 574 nm. Excitation spectra present two CT bands at 275 and 324 nm related to each emission center, respectively. Comparing the relative intensities between the emission spectra, the 0-->0 transition at 574 nm assigned to Eu3+-O2- associates in the Sr2SiO4:Eu3+ emission spectrum is much more intense than the same transition in the Sr2SiO4:Eu3+,Zn2+ emission spectrum. Moreover, in the Sr2SiO4:Eu3+ excitation spectrum, the intensity ratio between the CT band related to the Eu3+-O2- emission center and Eu3+ F-7-->L-5(6) transition is also larger than in the Sr2SiO4:Eu3+,Zn2+ one. Therefore, the presence of Zn2+ species provides an extra charge compensating mechanism, which decreases the formation of Eu3+-O2- associates. (C) 2002 Elsevier B.V. B.V. All rights reserved.

Conditions giving rise to intense visible room temperature photoluminescence in SrWO4 thin films: the role of disorder

The nature of intense visible photoluminescence at room temperature of SrWO4 (SWO) non-crystalline thin films is discussed in the light of experimental results and theoretical calculations. The SWO thin films were synthesized by the polymeric precursors method. Their structural properties have been obtained by X-ray diffraction data and the corresponding photoluminescence (PL) spectra have been measured. The UV-vis optical spectra measurements suggest the creation of localized states in the disordered structure. The photoluminescence measurements reveal that the PL changes with the degree of disorder in the SWO thin film. To understand the origin of visible PL at room temperature in disordered SWO, we performed quantum-mechanical calculations on crystalline and disordered SWO periodic models. Their electronic structures are analyzed in terms of DOS, hand dispersion and charge densities. We used DFT method with the hybrid non-local B3LYP approximation. The polarization induced by the symmetry break and the existence of localized levels favors the creation of trapped holes and electrons, giving origin to the room temperature photoluminescence phenomenon in the SWO thin films. (c) 2004 Elsevier B.V. All rights reserved.

Pharyngeal clearance and pharyngeal transit time determined by a biomagnetic method in normal humans

Clearance and transit time are parameters of great value in studies of digestive transit. Such parameters are nowadays obtained by means of scintigraphy and videofluoroscopy, with each technique having advantages and disadvantages. In this study we present a new, noninvasive method to study swallowing pharyngeal clearance (PC) and pharyngeal transit time (PTT). This new method is based on variations of magnetic flux produced by a magnetic bolus passing through the pharynx and detected by an AC biosusceptometer (ACB). These measurements may be performed in a simple way. cause no discomfort. and do not use radiation. We measured PC in 8 volunteers (7 males and I female. 23-33 years old) and PTT in 8 other volunteers (7 males and I female. 21-29 years old). PC was 0.82 +/- 0.10 s (mean +/- SD) and PTT was 0.75 +/- 0.03 s. The results were similar for PC but longer for PTT than those determined by means of other techniques. We conclude that the biomagnetic method can be used to evaluate PC and PTT.

Food intake and digestive efficiency in temperate wool and tropic semi-arid hair lambs fed different concentrate: forage ratio diets

This work was conducted to evaluate food intake and digestive efficiency of temperate wool and tropic semi-arid hair lambs, according to different concentrate: forage ratios in diet. Twenty-four lambs, averaging 90 +/- 1.8 days old and a mean body weight of 20 +/- 0.69 kg, 12 of them wool lambs, F, from Ideal x Ile de France crossing, and 12 others pure Santa Ines hair lambs, were distributed into a four replication 3 x 2 factorial arrangement consisting of three diets and two genotypes. Experimental diets consisted of: D1 = 60% concentrate mix (C) and 40% Cynodon sp. cv. Tifton-85 hay (F), D2 = 40% C and 60% F, and D3 = 20% C and 80% F. D1 was formulated for a daily gain of 300g per animal. Increasing forage levels in diets resulted in linear reductions (P < 0.01) in DM, OM, CP, TCH and metabolizable energy (ME) intake, and a linear increase (P < 0.01) in NDF ingestion. Tropic semi-arid hair lambs had higher DM, OM, NDF, CP, and TCH intake than temperate wool lambs. Although there were no genotype effects in OM and GE coefficient of digestibility, hair lambs showed more efficient (P < 0.05) digestibility of DM, CP, NDF and TCH. Increases in forage levels of diets corresponded to a negative linear effect (P < 0.01) in the apparent digestibility of DM, OM, CP, TCH and GE, while apparent digestibility of NDF increased linearly (P < 0.01). Total endogenous nitrogen (fecal plus urinary N) for F(1) Ideal x Ilede France wool and Santa Ines hair lambs were, respectively, 182 and 312 mg/kg(0.75) per day. Thus, Santa Ines tropic semi-arid hair lambs showed to be more responsive than F(1) Ideal x Ile de France temperate wool lambs to low quality fibrous diets. (C) 2004 Elsevier B.V. All rights reserved.

Structural and morphological characterization of Pb1-xBaxTiO3 thin films prepared by chemical route: An investigation of phase transition

Detailed room temperature micro-Raman scattering, X-ray diffraction, atomic force microscopy and specular reflectance infrared Fourier transform spectroscopy studies were carried out on soft chemical by processed Pb1-xBaxTiO3 thin films. The micro-Raman spectra pointed the existence of a stable tetragonal ferroelectric phase in the entire composition range (0 < x <= 1). The infrared reflectance spectra showed that the frequency of several peaks decreases as the Ba2+ concentration increases. These features are correlated to a decrease in the tetragonal distortion of the TiO6 octahedra as the Ba2+ concentration increases. Furthermore, as x increases from 0.70 to 1.0, the Raman spectrum shows an evolution towards the well-known Raman spectrum of the tetragonal BaTiO3. Therefore, we demonstrated that the combination of solid solution PbTiO3-BaTiO3 with a grain size in the order of 30-40 nm supports the tetragonal ferroelectric phase at room temperature. (C) 2007 Elsevier B.V. All rights reserved.