331 research outputs found

    Large-scale surface reconstruction energetics of Pt(100) and Au(100) by all-electron DFT

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    The low-index surfaces of Au and Pt all tend to reconstruct, a fact that is of key importance in many nanostructure, catalytic, and electrochemical applications. Remarkably, some significant questions regarding their structural energies remain even today, in particular for the large-scale quasihexagonal reconstructed (100) surfaces: Rather dissimilar reconstruction energies for Au and Pt in available experiments, and experiment and theory do not match for Pt. We here show by all-electron density-functional theory that only large enough "(5 x N)" approximant supercells capture the qualitative reconstruction energy trend between Au(100) and Pt(100), in contrast to what is often done in the theoretical literature. Their magnitudes are then in fact similar, and closer to the measured value for Pt(100); our calculations achieve excellent agreement with known geometric characteristics and provide direct evidence for the electronic reconstruction driving force.Comment: updated version - also includes EPAPS information as auxiliary file; related publications can be found at http://www.fhi-berlin.mpg.de/th/th.htm

    Long-term outcomes of antiproliferative agents in primary trabeculectomy

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    Purpose: To evaluate and compare long-term outcomes of trabeculectomies with subconjunctival injections of 5-fluorouracil (5-FU) after sugery or use of mitomycin C (MMC) during surgery. Methods: Retrospective study of 133 eyes who underwent primary trabeculectomy. Results: Intraocular pressure levels were not statistically significant at any of the postoperative visits when comparing the 5-fluorouracil and mitomycin C groups. In each group, analyzed separately, the intra-ocular pressure levels showed no statistically significant difference before or after surgery. The incidence of postoperative complications was not statistically significant as well, except for a greater incidence of the corneal epithelial defects, more frequent in the 5-fluorouracil group. In both groups, a greater incidence of development/progression of cataract was noted. Conclusion: Both mitomycin C and 5-fluorouracil promoted an important and stable decrease in intraocular pressure with similar complication rates.Objetivo: Avaliar comparativamente a longo prazo os resultados cirúrgicos de trabeculectomias nas quais foram utilizadas injeções subconjuntivais de 5-fluorouracil (5-FU) no pós-operatório ou aplicações de mitomicina C (MMC) peroperatória. Métodos: Estudo retrospectivo de 133 olhos submetidos a trabeculectomia primária. Resultados: A pressão ocular não apresentou valores estatisticamente significantes em nenhuma das visitas de pós-operatório quando comparados os grupos em que se utilizou a mitomicina C ou 5-fluorouracil. Em cada um dos grupos analisados separadamente, os níveis da pressão ocular não apresentaram diferenças estatisticamente significantes nos períodos pré e pós-operatório. A incidência de complicações pós-operatórias também não apresentou diferença estatisticamente significante à exceção de alterações epiteliais na córnea, mais freqüentes no grupo tratado com 5-fluorouracil. Nos dois grupos, destacou-se a elevada incidência de desenvolvimento/progressão de catarata. Conclusão: O uso de mitomicina C ou 5-fluorouracil promoveu redução importante e estável da pressão ocular, com índices de complicações semelhantes.Universidade Federal de São Paulo (UNIFESP) Departamento de OftalmologiaUniversidade de Miami Bascom Palmer Eye InstituteUNIFESP, Depto. de OftalmologiaSciEL

    Through the labyrinth of yesteryears

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    Background Allergy to dog (Canis familiaris) is a worldwide common cause of asthma and allergic rhinitis. However, dander extract in routine diagnostics is not an optimal predictor of IgE-mediated dog allergy. Our objective was to evaluate saliva as an allergen source for improved diagnostics of allergy to dog. Methods IgE-binding proteins in dog saliva and dander extract were analysed by immunoblot and mass spectrometry (LC-MS/MS) using pooled or individual sera from dog-allergic patients (n=13). Sera from 59 patients IgE positive to dander and 55 patients IgE negative to dander but with symptoms to dog were analysed for IgE against saliva and dander by ELISA. Basophil stimulation with dog saliva and dander extract was measured by flow cytometry among three dog-allergic patients. Additionally, IgE-binding protein profiles of saliva from different breeds were investigated by immunoblot. Results Greater number and diversity of IgE-binding proteins was found in saliva compared to dander extract and varied among dog breeds. In saliva, Can f 1, 2, 3 and 6 were identified but also four new saliva allergen candidates. The majority of the 59 dog danderpositive sera (n=44) were IgE positive to dog saliva. Among patients IgE negative to dander, but with symptoms to dog, 20% were IgE positive to saliva. The biological activity of saliva was confirmed by basophil degranulation. Conclusions Dog saliva is an allergen source for improved diagnostics of dog allergy. The IgE-binding protein profile of saliva from different dogs varies.Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/3488

    Strongly Temperature Dependent Sliding Friction for a Superconducting Interface

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    A sudden drop in mechanical friction, between an adsorbed nitrogen monolayer and a lead substrate, occurs when the lead passes through the superconducting transition temperature. We attribute this effect to a sudden drop at the superconducting transition temperature of the substrate Ohmic heating. The Ohmic heating is due to the electronic screening current that results from the sliding adsorbed film.Comment: Revte

    Variable Curvature Slab Molecular Dynamics as a Method to Determine Surface Stress

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    A thin plate or slab, prepared so that opposite faces have different surface stresses, will bend as a result of the stress difference. We have developed a classical molecular dynamics (MD) formulation where (similar in spirit to constant-pressure MD) the curvature of the slab enters as an additional dynamical degree of freedom. The equations of motion of the atoms have been modified according to a variable metric, and an additional equation of motion for the curvature is introduced. We demonstrate the method to Au surfaces, both clean and covered with Pb adsorbates, using many-body glue potentials. Applications to stepped surfaces, deconstruction and other surface phenomena are under study.Comment: 16 pages, 8 figures, REVTeX, submitted to Physical Review

    Dog saliva - an important source of dog allergens

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    Background Allergy to dog (Canis familiaris) is a worldwide common cause of asthma and allergic rhinitis. However, dander extract in routine diagnostics is not an optimal predictor of IgE-mediated dog allergy. Our objective was to evaluate saliva as an allergen source for improved diagnostics of allergy to dog. Methods IgE-binding proteins in dog saliva and dander extract were analysed by immunoblot and mass spectrometry (LC-MS/MS) using pooled or individual sera from dog-allergic patients (n=13). Sera from 59 patients IgE positive to dander and 55 patients IgE negative to dander but with symptoms to dog were analysed for IgE against saliva and dander by ELISA. Basophil stimulation with dog saliva and dander extract was measured by flow cytometry among three dog-allergic patients. Additionally, IgE-binding protein profiles of saliva from different breeds were investigated by immunoblot. Results Greater number and diversity of IgE-binding proteins was found in saliva compared to dander extract and varied among dog breeds. In saliva, Can f 1, 2, 3 and 6 were identified but also four new saliva allergen candidates. The majority of the 59 dog danderpositive sera (n=44) were IgE positive to dog saliva. Among patients IgE negative to dander, but with symptoms to dog, 20% were IgE positive to saliva. The biological activity of saliva was confirmed by basophil degranulation. Conclusions Dog saliva is an allergen source for improved diagnostics of dog allergy. The IgE-binding protein profile of saliva from different dogs varies.Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/3488
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