965 resultados para 2-PHASE SYSTEMS
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Context: Species of Baccharis exhibit antibiotic, antiseptic, and wound-healing properties, and have been used in the traditional medicine of South America for the treatment of inflammation, headaches, diabetes, and hepatobiliary disorders. Objective: To investigate the anti-inflammatory activity of organic phases from EtOH extract of the aerial parts of Baccharis uncinella DC (Asteraceae). Materials and methods: The crude EtOH extract from the aerial parts of B. uncinella was subjected to partition procedures and the corresponding CH(2)Cl(2) and EtOAc phases were subjected to several chromatographic separation procedures. Thus, these phases and their purified compounds were assayed for evaluation of anti-inflammatory activity. Results: The CH(2)Cl(2) phase from EtOH extract from B. uncinella contained two triterpenoids (oleanolic and ursolic acids) and one flavonoid (pectolinaringenin), whereas the respective EtOAc phase showed to be composed mainly by two phenylpropanoid derivatives (caffeic and ferulic acids). The CH(2)Cl(2) and EtOAc phases as well as their isolated compounds exhibited anti-inflammatory effects against inflammatory reactions induced by phospholipase A2 (from Crotalus durissus terrificus venom) and by carrageenan. Discussion and conclusion: The results suggested that the components obtained from partition phases of EtOH extract of B. uncinella could represent lead molecules for the development of anti-inflammatory agents. Additionally, the results confirmed the use of Baccharis genus in the traditional medicine of South America for the treatment of inflammation and other heath disorders. To date, the present work describes for the first time the anti-inflammatory effects of compounds isolated from B. uncinella.
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No presente trabalho, foram estudados os dados de equilíbrio de fases dos sistemas aquosos bifásicos formados por polietilenoglicol (1500, 3350 e 6000) + fosfato monobásico e dibásico de sódio (pH 7) + água. Estudou-se o efeito da variação da temperatura (10, 25 e 40°C) bem como da massa molar sobre os dados de equilíbrio. Para o PEG 3350 observou-se um aumento da área bifásica com diminuição da temperatura, mostrando que a formação do sistema aquoso bifásico é exotérmico. Para o PEG 1500 e 6000 houve aumento da área bifásica à 10 e 40°C se comparado à temperatura de 25°C. Em todas as temperaturas em estudo, o aumento da massa molar contribuiu para o aumento da área bifásica. Fato este que foi explicado pelo aumento do caráter hidrofóbico com o aumento da massa do polietilenoglicol.
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Relatório Final de Estágio apresentado à Escola Superior de Dança, com vista à obtenção do grau de Mestre em Ensino de Dança.
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Very large subsidence, with up to 20 km thick sediment layers, is observed in the East Barents Sea basin. Subsidence started in early Paleozoic, accelerated in Permo-Triassic times, finished during the middle Cretaceous, and was followed by moderate uplift in Cenozoic times. The observed gravity signal suggests that the East Barents Sea is at present in isostatic balance and indicates that a mass excess is required in the lithosphere to produce the observed large subsidence. Several origins have been proposed for the mass excess. We use 1-D thermokinematic modeling and 2-D isostatic density models of continental lithosphere to evaluate these competing hypotheses. The crustal density in 2-D thermokinematic models resulting from pressure-, temperature-, and composition-dependent phase change models is computed along transects crossing the East Barents Sea. The results indicate the following. (1) Extension can only explain the observed subsidence provided that a 10 km thick serpentinized mantle lens beneath the basin center is present. We conclude that this is unlikely given that this highly serpentinized layer should be formed below a sedimentary basin with more than 10 km of sediments and crust at least 10 km thick. (2) Phase changes in a compositionally homogeneous crust do not provide enough mass excess to explain the present-day basin geometry. (3) Phase change induced densification of a preexisting lower crustal gabbroic body, interpreted as a mafic magmatic underplate, can explain the basin geometry and observed gravity anomalies. The following model is proposed for the formation of the East Barents Sea basin: (1) Devonian rifting and extension related magmatism resulted in moderate thinning of the crust and a mafic underplate below the central basin area explaining initial late Paleozoic subsidence. (2) East-west shortening during the Permian and Triassic resulted in densification of the previously emplaced mafic underplated body and enhanced subsidence dramatically, explaining the present-day deep basin geometry.
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In the parallel map theory, the hippocampus encodes space with 2 mapping systems. The bearing map is constructed primarily in the dentate gyrus from directional cues such as stimulus gradients. The sketch map is constructed within the hippocampus proper from positional cues. The integrated map emerges when data from the bearing and sketch maps are combined. Because the component maps work in parallel, the impairment of one can reveal residual learning by the other. Such parallel function may explain paradoxes of spatial learning, such as learning after partial hippocampal lesions, taxonomic and sex differences in spatial learning, and the function of hippocampal neurogenesis. By integrating evidence from physiology to phylogeny, the parallel map theory offers a unified explanation for hippocampal function.
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A l'Est du fleuve Zanskar (Ladakh), la zone de suture de l'Indus sépare les nappes de la bordure nord-indienne du Gondwana (Haut-Himalaya, nappes du Zanskar, cristallin de Tso Morari) des éléments péri·gondwaniens du Trans-himalaya. Des recherches géologiques entreprises entre l'Indus el la Tsarap ont montré que: - la molasse autochlone du Ladakh est surmontée par un édifice de flysch et molasses tertiaires, rétrocharrié vers le NordEst et coiffé par les conglomérats post· éocène moyen du Stok Kangri et une formation eontinentale de molasse rouge; - - la zone de suture comprend deux unités. principales : a) au Nord et au Nord-Ouest, l'unité volcano-sédimentaire de Dras-Nindam avec des conglomérats et flysch crétacés, des brèches massives à radiolarHes et roches vertes; cette unité est accompagnée d'un mélange coloré à roches ultra-basiques, blocs exoti(Iues divers et une méga lentille de brèche carbonatée polygénique à grands Foraminifères (Nummulites ?) ; b) au Sud, l'unité de la Markha, un flysch à lentilles de calcaires plus ou moins marmoréens datée de la base du Jurassique moyen et que nons corrélons avec le Oysch de Lamayuru ; - l'unité complexe de Nimaling représente la terminaison occidentale du crist allin de Rupshn (Tso MOI'ari) ; il comprend un socle gneissique, des roches vert.es et une couverture de schistes quartzitiques, quartzites el dolomies. Cet ensemble est intrudé pal' un granite porphyrique et il est surmonté, en contact tectonique, par une épaisse série métamorphique de calcschistes, shales et grès de faciès schistes lustrés, d'âge inconnu; dans ce tte série, on note au moins trois phases de fortes déformaljons superposées (linéations replissées) ; le long de la vallée de la Markha, le style st.ructural évoque, avec des plis isoclinaux de 2" phase à axes verticaux, une « zone de racine" et pourrait également témoigner de mouvements horizontaux importants; - l'édifice des napp es du Zanskar a été subdivisé en trois unités; il surmonte vers le Nord-Est les schistes lustrés du groupe de Langtang et vient buter vers le Sud-Ouest, le long d'un aceident chevauchant, contre la nappe de Zangla (Haut Himalaya). Les séries sédimentaires (Trias - Crétacé supérieur) sont d'affinité téthysienne. De nouvelles datations sont apportées et nous mettons en évidence, directement à l'Est du fleuve Zanskar, la présence de Crétacé sous faciès calcaires multicolores à microfaune planctique ; transgressif sur les grès de Giumal, ce faciès calcaire déhut.e déjà dans l'Alhien supérieur, c'est-à-dire nellement plus tôt que dans les régions plus orientales de l 'Himalaya; - les nappes du Haut Himalaya comprennent du Nord-Est vers le Sud-Ouest la nappe de Zangla qui chevauche par l'intermédiaire d'une semelle de « Panjal Traps » des témoins écaillés de Paléozoïque inférieur, puis la nappe de cristallin. La nappe de Zangla correspond à l'unité qui, à l 'Ouest du Zanskar supporte la klippe ophiolitique de Spongtang.
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In bubbly flow simulations, bubble size distribution is an important factor in determination of hydrodynamics. Beside hydrodynamics, it is crucial in the prediction of interfacial area available for mass transfer and in the prediction of reaction rate in gas-liquid reactors such as bubble columns. Solution of population balance equations is a method which can help to model the size distribution by considering continuous bubble coalescence and breakage. Therefore, in Computational Fluid Dynamic simulations it is necessary to couple CFD and Population Balance Model (CFD-PBM) to get reliable distribution. In the current work a CFD-PBM coupled model is implemented as FORTRAN subroutines in ANSYS CFX 10 and it has been tested for bubbly flow. This model uses the idea of Multi Phase Multi Size Group approach which was previously presented by Sha et al. (2006) [18]. The current CFD-PBM coupled method considers inhomogeneous flow field for different bubble size groups in the Eulerian multi-dispersed phase systems. Considering different velocity field for bubbles can give the advantageof more accurate solution of hydrodynamics. It is also an improved method for prediction of bubble size distribution in multiphase flow compared to available commercial packages.
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Les interactions entre les systèmes de régulation du sodium et du calcium sont encore mal comprises et leur importance clinique mérite d'être étudiée plus en détail. Les études chez l'animal ont montré qu'il existe des relations entre le taux plasmatique d'hormone parathyroïdienne (PTH) et l'aldostérone ou l'activité de la rénine. Par ailleurs, il a été démontré chez l'animal et chez l'homme que le taux sanguin de PTH augmente rapidement après une injection de furosémide, un diurétique de l'anse ce qui fait penser qu'il existe un lien entre l'effet du furosémide sur le rein et la sécrétion de PTH. Toutefois, à ce jour, le(s) mécanisme(s) impliqués dans ce lien reste(nt) encore inconnu(s). Des résultats plus récents suggèrent que l'effet du furosemide est amoindri par l'administration préalable d'un calcimimétique agissant au niveau du récepteur sensible au calcium (calcium sensing receptor). Pour explorer chez l'homme, les mécanismes possibles du lien entre PTH et effet du furosemide sur le rein, nous avons planifié une étude randomisée croisée contre placebo réalisée chez 18 volontaires sains masculins. Le but principal était d'investiguer le rôle du système rénine-angiotensine et des calcium sensing receptors. L'étude s'est donc réalisée en 2 phases pour chaque sujet. Les participants ont ainsi reçu soit du cinacalcet (60mg) soit un placebo dans une première phase et le placebo ou du cinacalcet dans la 2° phase. Dans chaque phase d'évaluation, une injection de 20 mg de furosemide a été administrée par voie intraveineuse à l'équilibre soit 3 heures après la prise du placebo ou du cinacalcet. Des échantillons de plasma ont été prélevés toutes les 15 minutes pendant 1 heure puis toutes les heures pour le dosage de PTH intacte, calcium, sodium, potassium, magnésium, phosphate, activité de la rénine plasmatique et aldostérone jusqu'à 6h après l'injection de furosémide. L'excrétion urinaire de ces mêmes électrolytes a été mesurée aux mêmes intervalles.
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By the year 2005 the world biochemical market will reach an estimated $ 100 billion and separation processes are a vital link between lab discoveries and the fulfillment of this commercialization potential. The practical application of aqueous two-phase systems (ATPS) to extraction processes has been exploited for several years for the recovery of biological products. Unfortunately, this has not resulted in an extensive presence of the technique in commercial processes. In this paper a critical overview of the fundamental thermodynamic properties related to formation of aqueous two-phase systems and their application to extraction and purification of bioparticules is presented.
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The restricted availability of water sources suitable for consumption and high costs for obtaining potable water has caused an increase of the conscience concerning the use. Thus, there is a high demand for "environmentally safe methods" which are according to the principles of Green Chemistry. Moreover, these methods should be able to provide reliable results for the analysis of water quality for various pollutants, such as phenol. In this work, greener alternatives for sample preparation for phenol determination in aqueous matrices are presented, which include: liquid phase microextraction, solid phase microextraction, flow analysis, cloud point extraction and aqueous two-phase systems.
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The objectives of the present study were to explore three components of organizational commitment (affective [AC], normative [NC] and continuance [CC] commitment; Allen & Meyer, 1991), perceived relatedness (Oeci & Ryan, 1985; 2002), and behavioural intention (Ajzen, 2002) within the context of volunteer track and field officiating. The objectives were examined in a 2-phase study. Ouring phase 1, experts (N = 10) with domain familiarity assessed the item content relevance and representation of modified organizational commitment (OC; Meyer, Allen & Smith, 1993) and perceived relatedness (La Guardia, Oeci, Ryan & Couchman, 2000) items. Fourteen of 26 (p < .05) items were relevant (Aiken's coefficient V) and NC (M = 3.88, SO = .64), CC (M = 3.63, SD = .52), and relatedness (M = 4.00, SD = .93) items had mean item content-representation ratings of either "good" or "very good" while AC (M = 2.50, SD = 0.58) was rated "fair". Participants in phase 2 (N = 80) responded to items measuring demographic variables, perceptions of OC to Athletics Canada, perceived relatedness to other track and field officials, and a measure of intention (yiu, Au & Tang, 2001) to continue officiating. Internal consistency reliability estimates (Cronbach's (1951) coefficient alpha) were as follows: (a) AC = .78, (b) CC = .85, (c) NC = .80 (d) perceived relatedness = .70 and, (e) intention = .92 in the present sample. Results suggest that the track and field officials felt only minimally committed to Athletics Canada (AC M = 3.90, SD = 1.23; NC M = 2.47, SD = 1.25; CC M = 3.32; SD = 1.34) and that their relationships with other track and field officials were strongly endorsed (M = 5.86, SD = 0.74). Bivariate correlations (Pearson r) indicated that perceived relatedness to other track and field officials demonstrated the strongest relationship with intention to continue officiating (r = .346, p < .05), while dimensions of OC were not significantly related to intention (all p's > .05). Together perceived relatedness (j3 = .339, p = .004), affective commitment (j3 = -.1 53, p = .308), normative commitment (j3 = -.024, p = .864) and continuance commitment (j3 = .186, P = .287) contribute to the prediction of intention to continued officiating (K = .139). These relationships remained unaffected by the inclusion of demographic (j3age = -.02; P years with Athletics Canada = -.13; bothp's > .05) or alternative commitment (j3sport = -.19; P role = .15; Pathletes = .20; all p' s > .05) considerations. Three open-ended questions elicited qualitative responses regarding participants' reasons for officiating. Responses reflecting initial reasons for officiating formed these higher order themes: convenience, helping reasons, extension of role, and intrinsic reasons. Responses reflecting reasons for continuing to officiate formed these higher order themes: track and field, to help, and personal benefits. Responses reflecting changes that would influence continued involvement were: political, organizational/structural, and personal. These results corroborate the findings of previous investigations which state that the reasons underpinning volunteer motivations change over time (Cuskelly et al., 2002). Overall, the results of this study suggest that track and field officials feel minimal commitment to the organization of Athletics Canada but a stronger bond with their fellow officials. Moreover, the degree to which track and field officials feel meaningfully connected to one another appears to exert a positive influence on their intentions to continue officiating. As such, it is suggested that in order to promote continued involvement, Athletics Canada increases its focus on fostering environments promoting positive interactions among officials.
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The objective of this thesis was to demonstrate the potential of fast atom bombardment mass spectrometry (FABMS) as a probe of condensed phase systems and its possible uses for the study of hydrogen bonding. FABMS was used to study three different systems. The first study was aimed at investigating the selectivity of the ligand tris(3,6-dioxaheptyl) amine (tdoha) for the alkali metal cations. FABMS results correlated well with infrared and nmr data. Systems where a crown ether competed with tdoha for a given alkali metal cation were also investigated by fast atom bombardment. The results were found to correlate with the cation affinity of tdoha and the ability of the crown ether to bind the cation. In the second and third studies, H-bonded systems were investigated. The imidazole-electron donor complexes were investigated and FABMS results showed the expected H-bond strength of the respective complexes. The effects of concentration, liquid matrix, water content, deuterium exchange, and pre-ionization of the complex were also investigated. In the third system investigated, the abundance of the diphenyl sulfone-ammonium salt complexes (presumably H-bonded) in the FABMS spectrum were found to correlate with qualitative considerations such as steric hindrance and strength of ion pairs.
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Currently microporous oxidic materials including zeolites are attracting interest as potential hydrogen storage materials. Understanding how molecular hydrogen interacts with these materials is important in the rational development of hydrogen storage materials and is also challenging theoretically. In this paper, we present an incoherent inelastic neutron scattering (INS) study of the adsorption of molecular hydrogen and hydrogen deuteride (HD) in a copper substituted ZSM5 zeolite varying the hydrogen dosage and temperature. We have demonstrated how inelastic neutron scattering can help us understand the interaction of H-2 molecules with a binding site in a particular microporous material, Cu ZSM5, and by implication of other similar materials. The H-2 molecule is bound as a single species lying parallel with the surface. As H-2 dosing increases, lateral interactions between the adsorbed H-2 molecules become apparent. With rising temperature of measurement up to 70 K (the limit of our experiments), H-2 molecules remain bound to the surface equivalent to a liquid or solid H-2 phase. The implication is that hydrogen is bound rather strongly in Cu ZSM5. Using the simple model for the anisotropic interaction to calculate the energy levels splitting, we found that the measured rotational constant of the hydrogen molecule is reduced as a consequence of adsorption by the Cu ZSM5. From the decrease in total signal intensity with increasing temperature, we were able to observe the conversion of para-hydrogen into ortho-hydrogen at paramagnetic centres and so determine the fraction of paramagnetic sites occupied by hydrogen molecules, ca. 60%. (c) 2006 Elsevier B.V. All rights reserved.
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A simple parameter adaptive controller design methodology is introduced in which steady-state servo tracking properties provide the major control objective. This is achieved without cancellation of process zeros and hence the underlying design can be applied to non-minimum phase systems. As with other self-tuning algorithms, the design (user specified) polynomials of the proposed algorithm define the performance capabilities of the resulting controller. However, with the appropriate definition of these polynomials, the synthesis technique can be shown to admit different adaptive control strategies, e.g. self-tuning PID and self-tuning pole-placement controllers. The algorithm can therefore be thought of as an embodiment of other self-tuning design techniques. The performances of some of the resulting controllers are illustrated using simulation examples and the on-line application to an experimental apparatus.
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A self-tuning controller which automatically assigns weightings to control and set-point following is introduced. This discrete-time single-input single-output controller is based on a generalized minimum-variance control strategy. The automatic on-line selection of weightings is very convenient, especially when the system parameters are unknown or slowly varying with respect to time, which is generally considered to be the type of systems for which self-tuning control is useful. This feature also enables the controller to overcome difficulties with non-minimum phase systems.