2,978 research outputs found
INFLUENCE OF CERIUM ADDITION ON THE SYNTHESIS OF SOLIDS BASED ON PLATINUM SUPPORTED OVER ALUMINA-PILLARED CLAY
The present work shows the preparation and characterization of a set of solids by modification of a natural clay with Al, Ce and Pt. The characterization of the solids by X-ray diffraction (XRD) reveals the insertion of alumina pillars, whereas the subsequent impregnations of the pillared clay with Pt (II) or Ce (IV) do not lead to structural variations that can be observed by XRD. The characterization by nitrogen adsorption indicates that the incorporation of platinum species originates damages in the microporosity of the solid, while the addition of cerium prevents the deterioration of the textural propertie
Empleo de dos arcillas naturales colombianas en la eliminación de iones metálicos en solucion acuosa
Se caracterizaron dos arcillas naturales mediante fisiadsorción de nitrógeno a 77K, análisis químico e intercambio catiónico y se emplearon en la eliminación de iones contaminantes (Cu2+, Al3+ y Fe3+) en solución. Las eficiencias en la eliminación de estos contaminantes indican la potencialidad de dichos materiales en procesos de descontaminación de aguas residuales
Empleo de dos arcillas naturales colombianas en la eliminación de iones metálicos en solucion acuosa
Se caracterizaron dos arcillas naturales mediante fisiadsorción de nitrógeno a 77K, análisis químico e intercambio catiónico y se emplearon en la eliminación de iones contaminantes (Cu2+, Al3+ y Fe3+) en solución. Las eficiencias en la eliminación de estos contaminantes indican la potencialidad de dichos materiales en procesos de descontaminación de aguas residuales
Synthesis and size evolution of 1D hydroxyapatite crystals under surfactant-free hydrothermal conditions
Hydroxyapatite nanoparticulate materials have received a great deal of scientific
attention due to their dental and orthopedic applications but simple strategies to control particle
characteristics (e.g., surface area, shape and size distribution) are still needed. Among several
hydroxyapatite structures, one-dimensional nanoscale materials such as nanowires, nanorods and
nanobelts can be synthesized in the presence of specific surfactants added during synthesis in
order to alter the particle growth. This contribution is aim to explore strategies to obtain one
dimensional hydroxyapatite crystals without the use of surfactants. Particularly, we study the
effect of several variables such as temperature, reaction time and pH on shape and size of
hydroxyapatite crystals produced under hydrothermal conditions. The results obtained show the
formation of hydroxyapatite nanorods as well as some interesting insights about how to control
particle sizes in samples obtained at temperatures between 180 °C and 220 °C. These results
have potential benefits at the time of producing one dimensional hydroxyapatite crystals in a
simple and not expensive way
Caracterización de mujeres que cometieron homicidio contra su pareja o expareja
16 p.Esta investigación se enmarca en el eje correspondiente a la Psicología Criminológica, en la línea de perfilación y caracterización de hombres y mujeres que cometen homicidio contra sus parejas. El propósito de este estudio fue identificar las características de los casos de mujeres que cometen homicidio o tentativa de homicidio hacia sus parejas heterosexuales. Para lograr el objetivo, se tomaron los modelos propuestos por Garrido y Sobral (2008) y Morales (2003) para recoger y analizar la información a partir de la revisión de los expedientes judiciales de dicha población.Introducción
Metodología
Resultados
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Referencia
Psicometric properties of an instrument for measuring patient’s satisfaction with physical therapy (medrisk) in spanish population: cultural diversity
The Spanish-language versión of the MedRisk Insttrument for Mesauring Partient Satisfaction with Physical therapy Care was validated in a simple of 203 Spanish-speakers patients in New York City. The purpose of this investigation is to adapt this instrument to Spanish population (patients who assist to physical therapy services in Spain); to corroborate if exist a psychometric equivalence and to identify if Spanish patients consider relevant the same dimensions as the preliminary validation.
Relevance: At time to used a measurement instrument that has been validated in another country, it is necessary to assure that it is not only reliable and valid to the country where was developed, but also it needs to be appropriated to the patients subjects of the current investigation.
Participants: A total of 300 patients of the Hospital of San Juan de Dios del Aljarafe (in Sevilla, Spain) participated in this study (44% men and 56% women between 13 and 93 years old).
Methods: It has been done a cross-sectional descriptive study. Data were collected between April 2008 and November 2009.To the patients involved in the research, it was applied the original 20-item version of the MRPS (18 items and two global measures) and not the validated 12-item MRPS (10 items and two global measures). The main investigator randomly selected days during which the data were collected. The sample was taken finally on by convenience: all patients, in these selected days, who assist to medical care once they were done with their prescribed physiotherapy treatment.
Analysis: Like Spanish version in New York, factor structure was investigated using item-correlation and exploratory factor analysis. Group-level reliability for single test administration was assessed using the Cronbach alpha.
Results: Factor structure: the inter-item correlation matrix revealed that 3 items were not significantly correlated to both of the global measures . These 3 items were not included in the subsequent analysis. Principal components analysis revealed 4 eigenvalues greater than 2.0 explaining 67.93% of the cumulative variance. This suggested a 4-factor solutions. Following varimax rotation, a total of 14 items loaded on four factors were retained. Reliability: The Cronbach alpha was .87
Conclusions: Spanish version of MRPS that was validated with Spanish-speakers patients in New York is similar but not identical to the validation obtained with Spanish Population. In both of them, 9 of the 12 and 14 items finally selected in each other, have a coincidence. In the first one, there is a conclusion of two factors, internal and external. And in our investigation there were obtained 4 dimensions, 2 of them refer to internal factors (respect of the healthcare team and professional behavior of the therapist) and 2 that does it to external factors (adaptation of the center and accessibility)Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Environmental exposure to arsenic, AS3MT polymorphism and prevalence of diabetes in Mexico
Exposure to arsenic in drinking water is associated with increased prevalence of diabetes. We previously reported an association of diabetes and urinary concentration of dimethylarsinite (DMAsIII), a toxic product of arsenic methylation by arsenic ( +3 oxidation state) methyltransferase (AS3MT). Here we examine associations between AS3MT polymorphism, arsenic metabolism and diabetes. Fasting blood glucose, oral glucose tolerance and self-reported diagnoses were used to identify diabetic individuals. Inorganic arsenic and its metabolites were measured in urine. Genotyping analysis focused on six polymorphic sites of AS3MT. Individuals with M287T and G4965C polymorphisms had higher levels of urinary DMAsIII and were more frequently diabetic than the respective wild-type carriers, although the excess was not statistically significant. Odds ratios were 11.4 (95% confidence interval (CI) 2.2–58.8) and 8.8 (95% CI 1.6–47.3) for the combined effects of arsenic exposure >75th percentile and 287T and 4965C genotypes, respectively. Carriers of 287T and 4965C may produce more DMAsIII and be more likely to develop diabetes when exposed to arsenic
Benefits and risks of the hormetic effects of dietary isothiocyanates on cancer prevention
The isothiocyanate (ITC) sulforaphane (SFN) was shown at low levels (1-5 µM) to promote cell proliferation to 120-143% of the controls in a number of human cell lines, whilst at high levels (10-40 µM) it inhibited such cell proliferation. Similar dose responses were observed for cell migration, i.e. SFN at 2.5 µM increased cell migration in bladder cancer T24 cells to 128% whilst high levels inhibited cell migration. This hormetic action was also found in an angiogenesis assay where SFN at 2.5 µM promoted endothelial tube formation (118% of the control), whereas at 10-20 µM it caused significant inhibition. The precise mechanism by which SFN influences promotion of cell growth and migration is not known, but probably involves activation of autophagy since an autophagy inhibitor, 3-methyladenine, abolished the effect of SFN on cell migration. Moreover, low doses of SFN offered a protective effect against free-radical mediated cell death, an effect that was enhanced by co-treatment with selenium. These results suggest that SFN may either prevent or promote tumour cell growth depending on the dose and the nature of the target cells. In normal cells, the promotion of cell growth may be of benefit, but in transformed or cancer cells it may be an undesirable risk factor. In summary, ITCs have a biphasic effect on cell growth and migration. The benefits and risks of ITCs are not only determined by the doses, but are affected by interactions with Se and the measured endpoint
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