47 resultados para PSL


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BACKGROUND. The extracellular matrix (ECM) has important roles in prostatic development, and marked stromal changes take place in the rat ventral prostate (VP) after androgen deprivation. However, little knowledge exists about individual ECM components.METHODS. The distribution of elastic fibers (EF) and elastic-related fibers (ERF) in the VP of castrated and control rats was investigated, using histochemistry and transmission electron microscopy (TEM).RESULTS. EF are barely detected in the prostatic stroma, but ERF are relatively abundant. Castration results in a relative increase in the number and thickness of ERF. TEM showed an open network of ECM microfibrils throughout the stroma and thin and short EF, which increase in number and thickness after orchiectomy.CONCLUSIONS. The presence of elastic system components in the rat VP warrants the deformability required for the secretion exclusion under the action of smooth muscle cells, and the castration-induced modification may be related to the contraction of the tissue and maintenance of peculiar arrangements of other ECM components. (C) 1997 Wiley-Liss, Inc.

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The chromosomes of Hyla fuscovaria, H. hayii and II. prasina, with 2n=24, and of Hyla sp. (aff. circumdata), a new species, with 2n=24 and 2n=25, were studied.The karyotypes with 2n=24 in the four species were very similar, with almost no differences in the size and morphology of the chromosomes. The numerical variability found in Hyla sp. (aff. circumdata) is due to the occurrence of a supernumerary chromosome in some specimens. NOR data obtained for the first time in the four species and C banding analysis of H. prasina indicate that such types of banding may be useful to differentiate species with very similar karyotypes, contributing to the understanding of chromosome evolution and the establishment of phylogenetic relationships among Brazilian Hyla species.

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Stroma-epithelium relationships are of great relevance in prostatic morphogenesis and physiology, However, little knowledge exists about either stromal cells or extracellular matrix composition and arrangement in this system, Ultrastructural analysis revealed the existence of a microfibrillar system which occupies large areas of the rat prostatic stroma, In this work, we have applied immunocytochemistry and an ATP treatment for the ultrastructural identification of collagen type VI microfibrils, aiming at examining its participation in the prostatic microfibrillar network. Immunocytochemistry was also extended to a human case of prostatic nodular hyperplasia, Both methods succeeded in identifying collagen type VI in the rat ventral prostate, Collagen type VI is evenly distributed throughout the stroma but mainly associated with the basal lamina, collagen fibrils, and around the stromal cells, the use of ATP treatment allowed for the discrimination between collagen type VI and elastin-associated microfibrils, and demonstrated that these two classes of microfibrils establish an extended, mixed, and open network. The same aspects of association with the basal lamina, with stromal cells (particularly with smooth muscle cells), and with fibrillar components of the stroma were observed in the human tissue, We suggest that the collagen type VI and elastin-associated microfibril system may be involved in the control of some aspects of cellular behavior and may also play a structural role, maintaining the organ integrity after the deformations occurring under smooth muscle contraction.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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In dieser Arbeit werden zehn neue symmetrische (176,50,14) Designs und ein neues symmetrisches (144,66,30) Design durch Vorgabe von nichtauflösbaren Automorphismengruppen konstruiert. Im Jahre 1969 entdeckte G. Higman ein symmetrisches (176,50,14) Design, dessen volle Automorphismengruppe die sporadische einfache Gruppe HS der Ordnung 44.352.000 ist. Hier wurden nun Designs gesucht, die eine Untergruppe von HS zulassen. Folgende Untergruppen wurden betrachtet: die transitive und die intransitive Erweiterung einer elementarabelschen Gruppe der Ordnung 16 durch Alt(5), AGL(3,2), das direkte Produkt einer zyklischen Gruppe der Ordnung 5 mit Alt(5) und PSL(2,11). Die transitive Erweiterung von E(16) durch Alt(5) lieferte zwei neue Designs mit Automorphismengruppen der Ordnungen 960 bzw. 11.520; letzteres konnte auch mit der transitiven Erweiterung erhalten werden. Die Gruppe PSL(2,11) operiert auf den Punkten des Higman-Designs in drei Bahnen; sucht man nach symmetrischen (176,50,14) Designs, auf denen diese Gruppe in zwei Bahnen operiert, so erhält man acht neue Designs. Die übrigen Gruppen lieferten keine neuen Designs. Schließlich konnte ein neues symmetrisches (144,66,30) Design unter Verwendung der sporadischen Mathieu-Gruppe M(12) konstruiert werden. Dies war zu diesem Zeitpunkt außer dem Higman-Design das einzige bekannte symmetrische Design, dessen volle Automorphismengruppe im Wesentlichen eine sporadische einfache Gruppe ist.

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Gli aerosol, sospensione colloidale in aria di particelle solide o liquide, sono parte integrante dell’atmosfera. Essi interagiscono con la radiazione solare influenzando il clima (effetto primario e secondario) e la visibilità atmosferica. Gli aerosol hanno effetti sulla salute umana con patologie degli apparati cardiovascolare e circolatorio. La presente tesi affronta alcuni aspetti critici dei contatori ottici di particelle (OPC), utilizzati per caratterizzare l’aerosol ambientale. Gli OPC si basano sullo scattering luminoso per fornire la concentrazione in numero e la distribuzione dimensionale degli aerosol in tempo reale. Gli obiettivi di questa tesi sono: 1)caratterizzare e migliorare le prestazioni di un OPC di nuova concezione (CompactOPC N1, Alphasense; in seguito COPC) rispetto a un OPC standard commerciale (Grimm 1.108; in seguito GRM); 2)realizzare un banco di prova per la calibrazione di un OPC utilizzato in camere bianche e ambienti sanitari (Laser Particle Sensor 3715-00, Kanomax; in seguito LPS). Per questa attività ha mostrato interesse un’azienda locale (Pollution Clean Air Systems S.p.A.; Budrio, BO). Le prove sperimentali sono state effettuate con aerosol indoor e con particelle monodisperse di latex polistirene (PSL) di dimensioni differenti campionando in parallelo con i diversi OPC e su filtro per osservazioni al microscopio elettronico a scansione (SEM). In questo modo si è ottenuto un valore assoluto di riferimento per la concentrazione di aerosol. I risultati ottenuti indicano un buon accordo tra le concentrazioni di particelle fornite dal GRM e quelle ottenute al SEM. Il lavoro ha inoltre permesso di migliorare le prestazioni del COPC modificando la versione di base. Inoltre, è stata effettuata la calibrazione del LPS tramite il banco di prova realizzato nella tesi. Il lavoro sperimentale è stato svolto presso il Laboratorio di Aerosol e Fisica delle Nubi dell’Istituto di Scienze dell’Atmosfera e del Clima (ISAC) del Consiglio Nazionale delle Ricerche (CNR) a Bologna.

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Se analizan las características físicas, mecánicas, la patología y los usos de los productos derivados de la madera o compuestos, que tienen día a día mayor utilización por la industria de segunda transformación y usuarios finales, dada la versatilidad que tiene cada uno de estos productos. Los productos que se analizan son los siguientes: Vigas dúo, trío y perfiles laminados Madera laminada Madera microlaminada LVL Paralam PSL Madera tratada con productos protectores insecticida; fungicidas; ignifigos o/y protec6ores de la luz Madera acetilada Madera furfurylada Madera termotratada Composites Tableros alistonados Tableros contrachapados Tableros de partículas Tableros de fibras Tableros OSB Tableros de partículas cemento Tableros de viruta cemento Tableros atamborados Tableros ligeros

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Se analizan las características físicas, mecánicas, la patología y los usos de los productos derivados de la madera o compuestos, que tienen día a día mayor utilización por la industria de segunda transformación y usuarios finales, dada la versatilidad que tiene cada uno de estos productos. Los productos que se analizan son los siguientes: Vigas dúo, trío y perfiles laminados Madera laminada Madera microlaminada LVL Paralam PSL Madera tratada con productos protectores insecticida; fungicidas; ignifigos o/y protec6ores de la luz Madera acetilada Madera furfurylada Madera termotratada Madera densificada Composites Tableros alistonados Tableros contrachapados Tableros de partículas Tableros de fibras Tableros OSB Tableros de partículas cemento Tableros de viruta cemento Tableros atamborados Tableros ligeros

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Neste trabalho foi estudado o comportamento de hidróxi-calcogenetos (Se e Te) frente a biotransformações, empregando enzimas isoladas em meio orgânico ou aquoso e empregando microorganismos (fungos). Estudos comparativos sobre a influência de diversas variáveis, como solvente, temperatura, imobilização enzimática e estrutura do hidróxi-calcogeneto, foram realizados. Inicialmente os compostos foram sintetizados utilizando métodos descritos na literatura, em seguida foi estudada a resolução de hidróxiselenetos em meio orgânico empregando lipases isoladas (Esquema 1), (ver arquivo), incluindo um estudo de imobilização da PSL em diversos suportes, além do estudo da influência da variação do solvente, da temperatura, da lipase, etc. Na resolução em meio aquoso empregando enzimas isoladas, primeiramente os hidróxi-selenetos foram acetilados quimicamente e depois realizado uma triagem (com dez enzimas de diferentes fontes) empregando indicador de pH colori métrico. Posteriormente os acetatos dos hidróxi-selenetos (Esquema 2) (ver arquivo) foram submetidos à resolução enzimática em meio aquoso empregando as enzimas que foram selecionadas na triagem enzimática. As biotransformações utilizando fungos foram realizadas empregando células inteiras de algumas linhagens de Aspergillus terreus. Na seqüência foi realizada a resolução de hidróxi-teluretos em meio orgânico utilizando lipases isoladas (Esquema 3)(ver arquivo). Nessas resoluções também foi estudada a influência da variação do solvente, da lipase, do tempo, etc. De forma a demonstrar a importância dos compostos resolvidos, um hidróxi-seleneto quiral e dois hidróxi-teluretos quirais foram usados para preparar compostos pertencentes a classes de unidades estruturais de vasta ocorrência em produtos naturais: um álcool alílico e duas lactonas (Esquema 4)(ver arquivo).

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New geochronometers are needed for sediments of the Arctic Ocean spanning at least the last half million years, largely because oxygen-isotope stratigraphy is relatively ineffective in this ocean, and because other dating techniques require significant assumptions about sedimentation rates. Multi-aliquot luminescence sediment-dating procedures were applied to polymineral, fine-silt samples from 9 core-top and 37 deeper samples from 20 cores representing 19 sites across the Arctic Ocean. Most samples have independent age assignments and other known properties (e.g., % coarse fraction, % carbonate, U-Th isotopes). Thick-source alpha-particle counting indicates that for most regions the contribution of measured unsupported 230Th and 231Pa to calculated dose rates is PSL dating of polymineral fine-silt fractions from core-top and near-core-top samples indicates that three sites (mainly from the western Arctic Ocean) have long-bleach inherited ages of only 3-7 kyr, suggesting potential for accurate PSL and TL dating without an inherited correction when older interglacial samples are selected. Samples from a giant gravity core from the western region (Northwind Ridge) yield acceptable long-bleach TL and IR-PSL ages up to 100 kyr. A sample from the eastern region (near Gakkel Ridge) gives a long-bleach age of ca 60 kyr, agreeing with an independent age assignment. Several samples in the 10-40 kyr 14C range from other sites produce large long-bleach age overestimates, indicating the variable effects of ice-rafting and other depositional and bottom-currentreworking (re-suspension) processes during glacial stages. Short-bleach dating tests provide IR-PSL age estimates for core tops that appear to penetrate the 'reworking veil' of inherited ages, and not only suggest a procedure to greatly reduce long-bleach inherited ages but also have implications for the 14C reservoir correction. This study identifies the most promising regions for future luminescence dating, and suggests that for several regions of the Arctic Ocean, interglacial-stage (foram-'rich') sediments from ridge tops are preferred for the fine-grain luminescence dating methods.

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Mode of access: Internet.

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1. Phagocytic polymorphonuclear leucocytes (PMNLs) or neutrophils have a marked avidity for the uptake of particulate material and are the first cell type to respond to inflammatory stimuli in vivo. 2. By harnessing these pathophysiological characteristics the inherent targeting capacity of the PMNL could be exploited to carry drug loaded particles to these sites. 3. In vitro chemotaxis of PMNLs was studied in response to N-formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP) in the Blindwell chamber assay. 4. After phagocytosis of 1.1m polystyrene latex (PSL) beads at a range of incubation concentrations (5,10,20, and 30 beads/cell) the migration of the PMNL population was not significantly different from control, without beads. 5. The distribution of the beads within the filter showed that a disproportionately large number of PSL (50%) were associated with the cells on the surface of the filter that had not penetrated the filter. Eighty per cent of the PMNL population migrated and despite containing less PSL beads/cell, 50% of the dose was carried into the filter. Between 5 and 10% of these PSL were carried beyond 60m in the assay. 6. These results suggested heterogeneity of the PMNL population and to achieve efficient targeting with these cells preferential selection of the migratory sub-population would be needed. 7. The air-pouch model was then developed to study the focal accumulation of PMNLs in vivo. The PMNL isolated did not survive long enough in the circulation due to the trauma of the isolation procedure used; an alternative method will have to be employed.

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For decades scientists have attempted to use ideas of classical mechanics to choose basis functions for calculating spectra. The hope is that a classically-motivated basis set will be small because it covers only the dynamically important part of phase space. One popular idea is to use phase space localized (PSL) basis functions. This thesis improves on previous efforts to use PSL functions and examines the usefulness of these improvements. Because the overlap matrix, in the matrix eigenvalue problem obtained by using PSL functions with the variational method, is not an identity, it is costly to use iterative methods to solve the matrix eigenvalue problem. We show that it is possible to circumvent the orthogonality (overlap) problem and use iterative eigensolvers. We also present an altered method of calculating the matrix elements that improves the performance of the PSL basis functions, and also a new method which more efficiently chooses which PSL functions to include. These improvements are applied to a variety of single well molecules. We conclude that for single minimum molecules, the PSL functions are inferior to other basis functions. However, the ideas developed here can be applied to other types of basis functions, and PSL functions may be useful for multi-well systems.

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Sociologisk Forsknings digitala arkiv