157 resultados para affine features
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The construction of non-Abelian affine Toda models is discussed in terms of its underlying Lie algebraic structure. It is shown that a subclass of such non-conformal two-dimensional integrable models naturally leads to the construction of a pair of actions, which share the same spectra and are related by canonical transformations.
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The symmetry structure of the non-Abelian affine Toda model based on the coset SL(3)/SL(2) circle times U(1) is studied. It is shown that the model possess non-Abelian Noether symmetry closing into a q-deformed SL(2) circle times U(1) algebra. Specific two-vertex soliton solutions are constructed.
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The conformal affine sl(2) Toda model coupled to the matter field is treated as a constrained system in the context of Faddeev-Jackiw and the (constrained) symplectic schemes. We recover from this theory either the sine-Gordon or the massive Thirring model, through a process of Hamiltonian reduction, considering the equivalence of the Noether and topological currrents as a constraint and gauge fixing the conformal symmetry. (C) 2000 Academic Press.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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In this work structural features of anionic microemulsions, containing the pharmaceutical biocompatible components soya phosphatidylcholine (SPC), eumulgin HRE 40 (EU) and sodium oleate (SO) as surfactant, cholesterol (CHO) as oil phase and aqueous buffer were studied. Microemulsions were formulated with and without the antitumor drug doxorubicin (DOX). The various microstructures characterized in the pseudo-temary phase diagram were analyzed by polarized light microscopy, small-angle X-ray scattering (SAXS) and X-ray diffraction (XRD) as well as by their ability to incorporate and release DOX. The experimental results demonstrated a correlation between the composition, the structural features and drug delivery. It was found that at higher cholesterol contents, the crystallization of CHO polymorph phases changed the mobility of DOX molecules. Droplets were formed with short-range spatial correlation from a microemulsion (ME) with a low surfactant:oil ratio. More ordered structures with lamellar arrangements formed by the increasing of the CHO proportions in the formulation may be due to CHO crystallization. The in vitro release of DOX showed that the presence of a high content of crystalline CHO prolongs the release of DOX from ME. The retention of DOX in the internal oil phase of the ME may modulate the drug release for a prolonged time. These results clearly demonstrate the potential of ME as a drug-delivery system. (c) 2007 Elsevier B.V. All rights reserved.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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O diagnóstico laboratorial da raiva é realizado através de métodos de pesquisa do corpúsculo de Negri, imunofluorescência direta e inoculação em camundongos. Na maioria dos casos, quando a amostra é bem coletada, bem conservada e o profissional responsável possui experiência, verifica-se concordância entre as técnicas utilizadas. A Seção de Raiva e Encefalomielite do Instituto Biológico ao comparar a sensibilidade das três técnicas diagnósticas, em 3713 amostras (córtex cerebral, cerebelo e hipocampo) recebidas no período de 1980-1994, sendo 3010 da espécie bovina (983 positivas) e 703 da espécie eqüina (111 positivas), observou que, no caso da raiva eqüina, esta concordância não é mantida. Verificou-se, nesta espécie, que somente em algumas oportunidades foi possível identificar, pelo método histopatológico, o corpúsculo de Negri. em relação à prova de imunofluorescência pode-se afirmar que a mesma detectou uma porcentagem menor de amostras positivas, provenientes da espécie equina, em compração com as da espécie bovina, sendo esta diferença estatisticamente significativa. A prova biológica foi a mais sensível, porém houve uma diferença, também significativa, entre o período de incubação em camundongos das amostras de origem bovina e das de origem eqüina. A presença pouco frequente de corpúsculos de Negri e o período de incubação em camundongos mais prolongado, das amostras de origem eqüina, sugerem que devem ser intensificados os estudos da patogenia da raiva nesta espécie.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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The influence of yttrium oxide, Y2O3, on the microstructure development of the SnO(2)center dot Co(3)O(4)center dot Nb2O5 typical varistor system was studied with scanning (SEM) and transmission (TEM) electron microscopies. The different phases present in the studied samples were characterized through XRD, EDS and selected area diffraction patterns (SAD). Particles of Co2SnO4 were observed with TEM in every sample, whereas clusters of the pyrochlore phase T2Sn2O7 were observed with SEM in samples with 0.05, 0.10 and 0.25 mol% of Y2O3. The higher non-linearity (a = 16) was achieved with the addition of 0.05 mol% of Y2O3. The influence of the secondary phases on the electrical properties is also addressed in this work. (c) 2005 Published by Elsevier B.V.
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The harmful effects of nicotine on male genital system fertility have been reported in experimental and clinical studies. However, its effects on prostatic cells and glandular pathogenesis remain unclear. The aim of the present study was to analyse the histological, histochemical and ultrastructural alterations, in addition to stereology, of the ventral lobe of the prostate of rats, submitted to chronic nicotine administration, as well as to establish the relationship between these changes and prostate diseases. Twelve male Wistar rats (Rattus norvegicus) were divided into two experimental groups: group I (nicotine) and group II (control). Samples of the ventral prostate were collected, processed and submitted to histological analysis, acid phosphatase histochemistry and ultrastructural analysis by transmission and scanning electron microscopies. The results showed that in the nicotine group, the secretory epithelial cells of the ventral lobe of the prostate were atrophied, and prostatic intraepithelial neoplasia occurred and reduced the expression of acid phosphatase. The disorganisation of organelles involved in the glandular secretory process, accompanied by biomembrane destructuring, was also observed. In conclusion, nicotine causes drastic alterations in the secretory epithelium of the ventral prostate, compromising its function. Furthermore, nicotine also induces premalignant lesions in the prostate gland, thus representing a risk factor in the development of prostate diseases.
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Background: Hematology tests are useful to evaluate physiologic disturbances in fish and can provide important information for the diagnosis and prognosis of disease. Objectives: the primary purpose of this study was to define reference intervals for thrombocytes and leukocytes in healthy channel catfish (Ictalurus punctactus). In addition, the morphologic, cytochernical, and ultrastructural features of blood cells were assessed. Methods: Blood samples (0.5 mL were collected into EDTA from 40 clinically healthy catfish on a commercial fish farm in Jaboticabal, Brazil. Thrombocyte, total WBC, and differential WBC counts were determined and reference intervals were calculated as the 25-95th percentiles of data. Thrombocyte and leukocyte morphology was assessed in blood smears stained with May Griinwald-Giemsa-Wright and ultrastructurally by transmission electron microscopy. Cytochemical staining patterns were described using periodic acid-Schiff (PAS), peroxidase, nonspecific esterase, alkaline phosphatase, and toluidine blue. Results: Reference intervals were as follows: thrombocytes 58,802-99,569/mu L; total WBCs 27,460-41,523/mu L; lymphocytes 5380-11,581/mu L; monocytes 2949-7459/mu L; neutrophils 12,529-22,748/mu L, and basophils 736-2003/mu L. Neutrophils were positive for peroxidase and PAS; monocytes were positive for nonspecific esterase; and basophils were positive with toluidine blue. Conclusion: the morphologic and staining features of neutrophils and monocytes of channel catfish are similar to those of mammals, and the presence of basophils in this species was verified. These reference intervals and morphologic findings provide a foundation for future investigations on the functions and alterations of blood cells in channel catfish.