995 resultados para pre-oxidation


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RATIONALE: This study was intended to document the frequency of care complexity in liver transplant candidates, and its association with mood disturbance and poor health-related quality of life (HRQoL). METHODS: Consecutive patients fulfilling inclusion criteria, recruited in three European hospitals, were assessed with INTERMED, a reliable and valid method for the early assessment of bio-psychosocial health risks and needs. Blind to the results, they were also assessed with the Hospital Anxiety and Depression Scale (HADS). HRQoL was documented with the EuroQol and the SF36. Statistical analysis included multivariate and multilevel techniques. RESULTS: Among patients fulfilling inclusion criteria, 60 patients (75.9%) completed the protocol and 38.3% of them were identified as "complex" by INTERMED, but significant between-center differences were found. In support of the working hypothesis, INTERMED scores were significantly associated with all measures of both the SF36 and the EuroQol, and also with the HADS. A one point increase in the INTERMED score results in a reduction in 0.93 points in EuroQol and a 20% increase in HADS score. CONCLUSIONS: INTERMED-measured case complexity is frequent in liver transplant candidates but varies widely between centers. The use of this method captures in one instrument multiple domains of patient status, including mood disturbances and reduced HRQoL.

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The oxidation of GaAs and AlGaAs targets subjected to O2+ bombardment has been analyzed, using in situ x¿ray photoelectron spectroscopy, as a function of time until steady state is reached. The oxides formed by the O2+ bombardment have been characterized in terms of composition and binding energy. A strong energy and angular dependence for the oxidation of As relative to Ga is found. Low energies as well as near normal angles of incidence favor the oxidation of As. The difference between Ga and As can be explained in terms of the formation enthalpy for the oxide and the excess supply of oxygen. In an AlGaAs target the Al is very quickly completely oxidized irrespective of the experimental conditions. The steady state composition of the altered layers show in all cases a preferential removal of As.

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The changes undergone by the Si surface after oxygen bombardment have special interest for acquiring a good understanding of the Si+-ion emission during secondary ion mass spectrometry (SIMS) analysis. For this reason a detailed investigation on the stoichiometry of the builtup surface oxides has been carried out using in situ x-ray photoemission spectroscopy (XPS). The XPS analysis of the Si 2p core level indicates a strong presence of suboxide chemical states when bombarding at angles of incidence larger than 30°. In this work a special emphasis on the analysis and interpretation of the valence band region was made. Since the surface stoichiometry or degree of oxidation varies with the angle of incidence, the respective valence band structures also differ. A comparison with experimentally measured and theoretically derived Si valence band and SiO2 valence band suggests that the new valence bands are formed by a combination of these two. This arises from the fact that Si¿Si bonds are present on the Si¿suboxide molecules, and therefore the corresponding 3p-3p Si-like subband, which extends towards the Si Fermi level, forms the top of the respective new valence bands. Small variations in intensity and energy position for this subband have drastic implications on the intensity of the Si+-ion emission during sputtering in SIMS measurements. A model combining chemically enhanced emission and resonant tunneling effects is suggested for the variations observed in ion emission during O+2 bombardment for Si targets.

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Ni(II)-Fe(II)-Fe(III) layered double hydroxides (LDH) or Ni-containing sulfate green rust (GR2) samples were prepared from Ni(II), Fe(II) and Fe(III) sulfate salts and analyzed with X ray diffraction. Nickel is readily incorporated in the GR2 structure and forms a solid solution between GR2 and a Ni(II)-Fe(III) LDH. There is a correlation between the unit cell a-value and the fraction of Ni(II) incorporated into the Ni(II)-GR2 structure. Since there is strong evidence that the divalent/trivalent cation ratio in GR2 is fixed at 2, it is possible in principle to determine the extent of divalent cation substitution for Fe(II) in GR2 from the unit cell a-value. Oxidation forms a mixture of minerals but the LDH structure is retained if at least 20 % of the divalent cations in the initial solution are Ni(II). It appears that Ni(II) is incorporated in a stable LDH structure. This may be important for two reasons, first for understanding the formation of LDHs, which are anion exchangers, in the natural environment. Secondly, this is important for understanding the fate of transition metals in the environment, particularly in the presence of reduced Fe compounds.

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ABSTRACT Fat oxidation kinetics: effect of exercise. During graded exercise, absolute whole body fat oxidation rates increase from low to moderate intensities, and then markedly decline at high intensities, implying an exercise intensity (Fatmax) at which the fat oxidation rate is maximal (MFO). The main aim of the present work was to examine the effect of exercise on whole body fat oxidation kinetics. For this purpose, a sinusoidal mathematical model (SIN) has been developped in the first study to provide an accurate description of the shape of fat oxidation kinetics during graded exercise, represented as a function of exercise intensity, and to determine Fatmax and MFO. The SIN model incorporates three independent variables (i.e., dilatation, symmetry, and translation) that correspond to main expected modulations of the basic fat oxidation curve because of factors such as mode of exercise or training status. The results of study 1 showed that the SIN model was a valuable tool to determine Fatmax and MFO, and to precisely characterize and quantify the different shape of fat oxidation kinetics through its three variables. The effectiveness of the SIN model to detect differences in fat oxidation kinetics induced by a specific factor was then confirmed in the second study, which quantitatively described and compared fat oxidation kinetics in two different popular modes of exercise: running and cycling. It was found that the mean fat oxidation kinetics during running was characterized by a greater dilatation and a rightward asymmetry compared with the symmetric parabolic curve in cycling. In the two subsequent studies, the effect of a prior endurance exercise of different intensities and durations on whole body fat oxidation kinetics was examined. Study 3 determined the impact of a 1-h continuous exercise bout at an exercise intensity corresponding to Fatmax on fat oxidation kinetics during a subsequent graded test, while study 4 investigated the effect of an exercise leading to a more pronounced muscle glycogen depletion. The results of these two latter studies showed that fat oxidation rates, MFO, and Fatmax were enhanced following endurance exercise, but were increased to a greater extent with a more severe mucle glycogen depletion, inducing therefore modifications in the postexercise fat oxidation kinetics (i.e., greater dilatation and rightward asymmetry). In perspective, further studies have been suggested 1) to assess physiological meaning of the three independent variables of the SIN model; and 2) to compare the effect of two different training programs on fat oxidation kinetics in obese subjects.

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The intensive use of land alters the distribution of the pore size which imparts consequences on the soil physical quality. The Least Limiting Water Range (LLWR) allows for the visualization of the effects of management systems upon either the improvement or the degradation of the soil physical quality. The objective of this study was to evaluate the physical quality of a Red Latosol (Oxisol) submited to cover crops in the period prior to the maize crop in a no-tillage and conventional tillage system, using porosity, soil bulk density and the LLWR as attributes. The treatments were: conventional tillage (CT) and a no-tillage system with the following cover crops: sunn hemp (Crotalaria juncea L.) (NS), pearl millet (Pennisetum americanum (L.) Leeke) (NP) and lablab (Dolichos lablab L.) (NL). The experimental design was randomized blocks in subdivided plots with six replications, with the plots being constituted by the treatments and the subplots by the layers analyzed. The no-tillage systems showed higher total porosity and soil organic matter at the 0-0.5 m layer for the CT. The CT did not differ from the NL or NS in relation to macroporosity. The NP showed the greater porosity, while CT and NS presented lower soil bulk density. No < 10 % airing porosity was found for the treatments evaluated, and value for water content where soil aeration is critical (θPA) was found above estimated water content at field capacity (θFC) for all densities. Critical soil bulk density was of 1.36 and 1.43 Mg m-3 for NP and CT, respectively. The LLWR in the no-tillage systems was limited in the upper part by the θFC, and in the bottom part, by the water content from which soil resistance to penetration is limiting (θPR). By means of LLWR it was observed that the soil presented good physical quality.

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Comprend : [Frontispice : Pape, moine, personnification de l'Eglise. Armoiries. XVIè siècle.] [cote : microfilm m 10858/R 15836] ; [pl. en reg. p.90 : élévation d'une croix pour la bénédiction de l'Ile de Maragnan. XVIIè siècle.] [cote : microfilm m 10858/R 15836] ; [pl. en reg. p.348 : indigène de l'Ile de Maragnan, nommé François Carypyra, de la tribu des Tabaiares. XVIIè siècle.] François Carypyra. [cote : microfilm m 10858/R 15836] ; [pl. en reg. p.356 : indigène de l'Ile de Maragnan, nommé Jacques Patova. XVIIè siècle.] Jacques Patova. [cote : microfilm m 10858/R 15836] ; [pl. en reg. p.359 : indigène de l'Ile de Maragnan, nommé Antoine Manen, natif de Renary, originaire de Para de l'Ouest. XVIIè siècle.] Anthoine Manen. [cote : microfilm m 10858/R 15836] ; [pl. en reg. p.362 : indigène de l'Ile de Maragnan, nommé Itapoucou Topinamba et baptisé Louis-Marie. XVIIè siècle.] Louis Marie. [cote : microfilm m 10858/R 15836] ; [pl. en reg. p.364 : indigène de l'Ile de Maragnan, nommé Ouäroyio Topinamba et baptisé Louis-Henry. XVIIè siècle.] Louis Henri. [cote : microfilm m 10858/R 15836] ; [pl. en reg. p.365 : indigène de l'Ile de Maragnan, nommé Iapouäy et baptisé Louis de Saint-Jean. XVIIè siècle.] Louis de St. Iehan. [cote : microfilm m 10858/R 15836]

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Evidence is accumulating that total body mass and its relative composition influence the rate of fat utilization in man. This effect can be explained by two factors operating in concert: (i) the effect of the size of the tissue mass and (ii) the nature of the fuel mix oxidized, i.e. the proportion of energy derived from fat vs. carbohydrate. In a cross-sectional study of 307 women with increasing degrees of obesity, we observed that the respiratory quotient (RQ) in post-absorptive conditions became progressively lower with increased body fatness, indicating a shift in substrate utilization. However, the RQ is known to be also influenced by the diet commonly ingested by the subjects. A short-term mixed diet overfeeding in lean and obese women has also demonstrated the high sensitivity of RQ to changes in energy balance. Following a one-day overfeeding (2500 kcal/day in excess of the previous 24 h energy expenditure), the magnitude of increase in RQ was identical in lean and obese subjects and the net efficiency of substrate utilization and storage was not influenced by the state of obesity.