301 research outputs found

    Influence of corrugation angle in the stirred yoghurt processing in plate heat exchangers

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    Research on heat transfer of non-Newtonian fluids during thermal processing is useful to optimise the heat exchanger design, as well as to define quality levels of the final product. In the present study, a nonisothermal and non-Newtonian flow in plate heat exchangers was simulated numerically, in order to evaluate the influence of corrugation angle on the thermal and hydrodynamics characteristics of yoghurt during cooling in a plate heat exchanger (PHE). Cooling treatment of stirred yoghurt is usually carried out in PHEs since these equipments are suitable for liquid-liquid heat transfer duties that require uniform and rapid cooling or heating. In this operation, two mechanisms of heat transfer occur: conduction, in the plates, and convection inside the channels. The set of equations that describe mathematically the problem were the Navier-Stokes equations, for incompressible and stationary flow, and Fourier’s law for the conduction problems. Additionally, a constitutive model that describes the rheological properties of yoghurt under the cooling conditions has to be established in order to define totally the problem. The used model was proposed by Afonso et al. (2003) and takes into account the influence of shear rate and temperatur

    Correlation between BMI and motor coordination in children

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    Objectives: To analyze the association between motor coordination (MC) and body mass index (BMI) across childhood and early adolescence. Design: This study is cross-sectional. Methods: Data were collected in 7175 children (boys n = 3616, girls n = 3559), ages 6–14 years. BMI was calculated from measured height and weight [body mass (kg)/height (m2)]. Motor coordination was evaluated using Kiphard-Schilling’s body coordination test (KTK). Spearman’s rank correlation was used to study the association between BMI and MC. A Kruskal–Wallis test was used to analyze the differences in MC between children of normal weight, overweight and obese children. Results: Correlations between MC and BMI were negative and varied between 0.05 and 0.49. The highest negative correlations for both boys and girls was at 11 years of age. There was a general pattern of increasing negative correlations in both genders from 6 to 11 years of age and then a decrease in correlation strengths through 14 years of age. In both boys (χ2 (2) = 324.01; p < 0.001) and girls (χ2 (2) = 291.20; p < 0.001) there were significant differences in MC between the three groups’ weight status. Normal weight children of both sexes demonstrated significantly higher MC scores than overweight. Obese children in both sexes had the lowest MC scores among all three groups. Conclusion: Motor coordination demonstrated an inverse relationship with BMI across childhood and into early adolescence. The strength of the inverse relation increased during childhood, but decreased through early adolescence. Overweight and obese children of both sexes demonstrated significantly lower MC than normal weight children

    Advanced oxidation processes for remediation of azo dyes used in the textile industry

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    O objectivo deste trabalho visa avaliar a degradação fotocatalitica dos corantes azo Remazol Amarelo Ouro, Azul e Carbon RGB. Para tal foram avaliados os seguintes parâmetros: concentração de TiO2, concentração do corante, efeito do H2O2, efeito do pH e da reciclagem de TiO2. TiO2 Degussa P25 foi testado em concentrações a partir de 0gL-1 a 1 gL-1. A concentração do corante foi de 30 mgL-1 a 120 mgL-1 e a concentração do peróxido de hidrogénio foi de 0.3x10-3 a 6x10-2 mol L-1. A variação do pH foi de 2 a 11 e de reciclagem de TiO2 foi feita com 5 ciclos. As amostras foram tratadas durante duas horas com irradiação artificial (lâmpada de vapor mercúrio, 125W) e as amostras foram recolhidas aos 0, 15, 30, 45, 60, 90 e 120 minutos. A fotodegradação das amostras foi seguida por espectroscopia UV-Vis. A eficiência da degradação fotocatalítica aumentou com o aumento da quantidade de TiO2. O efeito do H2O2 foi benéfico para a degradação dos 3 corantes. Os resultados indicam que a degradação fotocatalítica depende da concentração de corante, da quantidade de fotocatalisador utilizado, irradiação UV vs tempo, do pH da solução e da concentração de peróxido de hidrogénio adicionado

    Relationship between Crystal Shape, Photoluminescence, and Local Structure in SrTiO3 Synthesized by Microwave-Assisted Hydrothermal Method

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    This paper describes the effect of using different titanium precursors on the synthesis and physical properties of SrTiO3 powders obtained by microwave-assisted hydrothermal method. X-ray diffraction measurements, X-ray absorption near-edge structure (XANES) spectroscopy, field emission scanning electron microscopy (FE-SEM), and high-resolution transmission electron microscopy (HRTEM) were carried out to investigate the structural and optical properties of the SrTiO3 spherical and cubelike-shaped particles. The appropriate choice of the titanium precursor allowed the control of morphological and photoluminescence (PL) properties of SrTiO3 compound. The PL emission was more intense in SrTiO3 samples composed of spherelike particles. This behavior was attributed to the existence of a lower amount of defects due to the uniformity of the spherical particles

    Manifestações Neuropsiquiátricas no Lupus Eritematoso Sistémico - A propósito de um caso clínico

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    O Lupus Eritematoso Sistémico (LES) é uma doença auto-imune de etiologia desconhecida, que evolui por surtos. É caracterizada por períodos de relativa quiescência e outros de exacerbação e pode envolver vários órgãos ou sistemas: A propósito de uma mulher jovem com um quadro clínico de delirium, revêem-se os dados existentes na literatura sobre as manifestações neuro-psiquiátricas do LES

    Enhancing reductive cleavage of aromatic carboxamides

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    [GRAPHICS] A set of aromatic and especially heteroaromatic N-benzyl carboxamides, derived from naphthalene, pyridine, pyrazine, and quinoline, and the corresponding tert-butyl acylcarbamates have been synthesized and studied by cyclic voltammetry with respect to facilitated reduction. The latter undergo regiospecific cleavage of their C(O)-N bonds under very mild reductive conditions with formation of Boc-protected (benzyl)amine in most cases in nearly quantitative yields, Examples of preparative cleavage by controlled potential electrolysis, activated aluminum, and NaBH4 are given

    Unveiling the efficiency of microwave-assisted hydrothermal treatment for the preparation of SrTiO3 mesocrystals

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    Material processing has become essential for the proper control, tuning and consequent application of the properties of micro/nanoparticles. In this case, we report herein the capability of the microwaveassisted hydrothermal (MAH) method to prepare the SrTiO3 compound, as a case study of inorganic compounds. Analyses conducted by X-ray diffraction, X-ray photoelectron and X-ray absorption spectroscopies confirmed that the MAH route enables the formation of pristine SrTiO3. The results indicated that the combination of thermal and non-thermal effects during the MAH treatment provides ideal conditions for an efficient and rapid synthesis of pristine SrTiO3 mesocrystals. Scanning electron microscopy images revealed a cube-like morphology (of ca. 1 mm) formed via a self-assembly process, influenced by the MAH time. Additionally, photoluminescence measurements revealed a broad blue emission related to intrinsic defects, which decreased with the MAH synthesis time

    Cytochrome P450/ABC transporter inhibition simultaneously enhances ivermectin pharmacokinetics in the mammal host and pharmacodynamics in Anopheles gambiae

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    Mass administration of endectocides, drugs that kill blood-feeding arthropods, has been proposed as a complementary strategy to reduce malaria transmission. Ivermectin is one of the leading candidates given its excellent safety profile. Here we provide proof that the effect of ivermectin can be boosted at two different levels by drugs inhibiting the cytochrome or ABC transporter in the mammal host and the target mosquitoes. Using a mini-pig model, we show that drug-mediated cytochrome P450/ABC transporter inhibition results in a 3-fold increase in the time ivermectin remains above mosquito-killing concentrations. In contrast, P450/ABC transporter induction with rifampicin markedly impaired ivermectin absorption. The same ketoconazole-mediated cytochrome/ABC transporter inhibition also occurs outside the mammal host and enhances the mortality of Anopheles gambiae. This was proven by using the samples from the mini-pig experiments to conduct an ex-vivo synergistic bioassay by membrane-feeding Anopheles mosquitoes. Inhibiting the same cytochrome/xenobiotic pump complex in two different organisms to simultaneously boost the pharmacokinetic and pharmacodynamic activity of a drug is a novel concept that could be applied to other systems. Although the lack of a dose-response effect in the synergistic bioassay warrants further exploration, our study may have broad implications for the control of parasitic and vector-borne diseases

    Estudio de la estructura interna de los cúmulos del Survey VISCACHA

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    El analisis de la estructura interna de los cúmulos estelares nos puede brindar informacion importante acerca de la formación y evolución dinámica de los mismos. Utilizando los datos del Survey VISCACHA se realizo el estudio de la distribución espacial de estrellas en 83 cúmulos pertenecientes a las periferias de La Nube Menor y de la Nube Mayor de Magallanes. A través de la construcción del minimum spanning tree, se pudo caracterizar la estructura interna de cada cumulo, obteniéndose los parámetros m, s y Q, los cuales son útiles para distinguir entre distribuciones de puntos radiales, homogéneas o con subestructuras. También se investigo la dependencia de estos parámetros con las distintas características de los cúmulos, como son sus edades y distribución espacial.The analysis of the internal structure of star clusters can provide us important information abouttheir formation and dynamic evolution. Using data from the VISCACHA Survey, we studied the stars spatialdistribution in 83 clusters belonging to the peripheries of the Large Magellanic Cloud and the Small MagellanicCloud. Through the construction of the minimum spanning tree, it was possible to characterize the internalstructure of each cluster, obtaining the parameters m, s and Q, which are useful for distinguishing betweenradial, homogeneous or substructured distributions. The dependence of these parameters with the differentcharacteristics of the clusters, such as their ages and spatial distribution, was also investigated.Fil: Rodriguez, Maria Jimena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; ArgentinaFil: Dias, Bruno. Universidad de Tarapacá; ChileFil: Maia, F. S. M.. Universidade Federal do Rio de Janeiro; BrasilFil: Feinstein Baigorri, Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; ArgentinaFil: Baume, Gustavo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; ArgentinaFil: Kerber, L.. No especifíca;Fil: dos Santos, J. F. C.. No especifíca;63° Reunión Anual de la Asociación Argentina de AstronomíaCordobaArgentinaAsociación Argentina de Astronomí
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