529 research outputs found

    Fluids at interfaces: Casimir effect, depletion and thermo-osmosis.

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    The critical Casimir effect is the long-range interaction between two planar walls in a critical fluid due to the confinement, achieved by the wall interfaces, of the critical density fluctuations. In this Thesis we provide a microscopic description of the critical Casimir force, introducing a novel density functional approximation coupled to the hierarchical reference theory of fluids. The depletion interaction is an effective attractive force arising between colloidal particles immersed in a solvent: The first prediction of this effect dates back to the seminal work by Asakura and Oosawa and has been obtained assuming that the colloidal particles were perfectly smooth spheres immersed in an ideal gas. In this Thesis we address the study of the interaction potential mediated by an ideal gas between two rough colloidal particles, as a function of the geometry, the dimension and the spatial configuration of the corrugations. When a thermal gradient is applied to a fluid at contact with a surface a stationary flow develops. This effect, referred to as thermo-osmosis, has been discovered in the late nineteenth century but successful theoretical descriptions have been up to now devised only when the fluid is a rarefied gas. In this thesis we presents a microscopic theory of thermo-osmosis based on a generalisation of linear response theory to inhomogeneous and anisotropic environments and to thermal disturbances

    3-Ethyl-9-phenyl-2-tosyl-2,3,3a,4,9,9a-hexahydro-1H-pyrrolo[3,4-b]quinoline

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    In the mol­ecule of the title compound, C26H28N2O2S, the pyrrolidine ring adopts an envelope conformation and the tetra­hydro­pyridine ring is in a half-chair conformation; these two rings are trans-fused. The dihedral angle between the pyridine- and sulfonyl-bound benzene rings is 36.15 (5)°. In the crystalline state, the mol­ecules are linked into a two-dimensional network parallel to the ab plane by C—H⋯O and C—H⋯π inter­actions

    Participação da substância cinzenta periaquedutal dorso-lateral na modulação do efeito ansiogênico do pentilenotetrazol em ratos submetidos ao labirinto em cruz elavado

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    Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências da Saúde. Programa de Pós-Graduação em Farmacologia.Estudos prévios demonstraram que a administração sistêmica de [pentilenotetrazol] (PTZ) causa uma redução da exploração dos braços abertos em ratos submetidos ao [labirinto em cruz elevado] (LCE), interpretada como um [efeito tipo-ansiogênico]. Um perfil semelhante de comportamento é observado em ratos submetidos ao LCE após a estimulação química com glutamato na [substância cinzenta periaquedutal dorso-lateral] (SCPdl). No presente trabalho procuramos investigar o papel da SCPdl na modulação do efeito tipo-ansiogêncio do PTZ em ratos submetidos ao teste/re-teste no LCE. Nossos resultados confirmaram o efeito tipo-ansiogênico do PTZ sistêmico em ratos que receberam líquor na SCPdl. O efeito do PTZ foi bloqueado após administração de lidocaína na SCPdl, mas não no colículo superior, de ratos submetidos ao teste no LCE, sugerindo que a SCPdl seria uma estrutura chave na expressão do efeito tipo-ansiogênico induzido pelo PTZ. Além disso, nossos resultados sugerem também que os neurotransmissores GABA e GLU presentes na SCPdl parecem mediar a expressão do efeito tipo-ansiogênico do PTZ, uma vez que o aumento da atividade GABAérgica ou a redução da atividade glutamatérgica bloquearam o efeito do PTZ sistêmico. Os resultados obtidos a partir do protocolo teste/re-teste sugerem que a SCPdl estaria envolvida na mediação da expressão do efeito ansiogênico do PTZ, porém não estaria relacionada à aquisição de aprendizado. Em resumo, nossos resultados sugerem um papel importante da SCPdl na organização da resposta animal para um medo aumentado, como o produzido pelo PTZ

    Cyclooxygenase-2 inhibitors. 1,5-diarylpyrrol-3-acetic esters with enhanced inhibitory activity toward cyclooxygenase-2 and improved cyclooxygenase-2/cyclooxygenase-1 selectivity.

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    he important role of cyclooxygenase-2 (COX-2) in the pathogenesis of inflammation and side effect limitations of current COX-2 inhibitor drugs illustrates a need for the design of new compounds based on alternative structural templates. We previously reported a set of substituted 1,5-diarylpyrrole derivatives, along with their inhibitory activity toward COX enzymes. Several compounds proved to be highly selective COX-2 inhibitors and their affinity data were rationalized through docking simulations. In this paper, we describe the synthesis of new 1,5-diarylpyrrole derivatives that were assayed for their in vitro inhibitory effects toward COX isozymes. Among them, the ethyl-2-methyl-5-[4-(methylsulfonyl)phenyl]-1-[3-fluorophenyl]-1H-pyrrol-3- acetate (1d), which was the most potent and COX-2 selective compound, also showed a very interesting in vivo anti-inflammatory and analgesic activity, laying the foundations for developing new lead compounds that could be effective agents in the armamentarium for the management of inflammation and pain

    The effect of manganese and silicon additions on the corrosion resistance of a polycrystalline nickel-based superalloy

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    The service lives of nickel superalloys are often limited by environmental degradation. The present study compares oxidation, sulfidation and hot corrosion at 750C of three variants of a polycrystalline superalloy: a baseline alloy, a variant containing 1wt% Mn and one containing 0.5wt% Si. Mn reduced the oxidation rate without changing the scale morphology. The MnCr2O4 scale formed proved more protective against sulfidation and hot corrosion, but internal sulfides extended the damage depth. Si modified the oxide morphology to a continuous Cr2O3-Al2O3 dual layer. This provided improved protection, reducing the sulfidation depth by 2/3 and the hot corrosion depth by 1/2.Comment: 21 page
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