10 research outputs found

    Silica-Copper Oxide Composite Thin Films as Solar Selective Coatings Prepared by Dipping Sol Gel

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    Silica-copper oxide (silica-CuO) composite thin films were prepared by a dipping sol-gel route using ethanolic solutions comprised TEOS and a copper-propionate complex. Sols with different TEOS/Cu-propionate (Si/Cu) molar ratios were prepared and applied on stainless steel substrates using dipping process. During the annealing process, copper-propionate complexes developed into particulate polycrystalline CuO dispersed in a partially crystallized silica matrix, as indicated by the X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses. The gel thermal analysis revealed that the prepared material might be stable up to 400°C. The silica-CuO/stainless steel system was characterized as a selective absorber surface and its solar selectivity parameters, absorptance (α), and emittance (Δ) were evaluated from UV-NIR reflectance data. The solar parameters of such a system were mostly affected by the thickness and phase composition of the SiO2-CuO film. Interestingly, the best solar parameters (α = 0.92 and Δ = 0.2) were associated to the thinnest films, which comprised a CuO-Cu2O mixture immersed in the silica matrix, as indicated by XPS

    SĂ­ndrome de nevos azules ahulados: reporte de un caso

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    ResumenEl sĂ­ndrome de nevos azules ahulados (SNAA) es un sĂ­ndrome poco frecuente, que se caracteriza por la presencia de mĂșltiples malformaciones vasculares en piel y tracto gastrointestinal. TambiĂ©n pueden verse afectados otros Ăłrganos con diferentes manifestaciones clĂ­nicas tales como artralgias, epistaxis, hemoptisis, hematuria, hemotĂłrax, trombocitopenia leve, coagulopatĂ­a por consumo y deformaciones Ăłseas, entre otras. Se presenta el caso en un niño de nueve años de edad con SNAA, con manifestaciones clĂ­nicas caracterĂ­sticas, tales como lesiones cutĂĄneas puntiformes de color violĂĄceo con tamaño variable y malformaciones vasculares gastrointestinales con sangrado de tubo digestivo.AbstractBlue Rubber Bleb Nevus Syndrome (BRBS) is a rare disease, characterized by multiple vascular malformations in the skin and gastrointestinal tract. Other organs can also be affected, presenting different clinical manifestations such as arthralgia, epistaxis, hemoptysis, hematuria, hemothorax, mild thrombocytopenia, consumptive coagulopathy, and bone deformities, among others. We present a case of BRBS in a nine-year-old boy with the characteristic clinical manifestations of punctated purplish-blue skin lesions that vary in size and gastrointestinal vascular malformations with upper digestive tract bleeding
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