2,577 research outputs found
Self-management of vascular risk factors
No full textSummary The aim of this thesis was to provide insight into the potential of a self-management approach in treatment of vascular risk factors and to develop a self-management intervention. Furthermore to examine if this intervention, based on self-efficacy promoting theory, is effective in reducing vascular risk factors in patients with established vascular diseases. Patients with different manifestations of vascular diseases appeared to have high levels of self-efficacy concerning the self-management tasks necessary for adequate vascular risk reduction. When those patients had diabetes, overweight (BMI > 30 kg/m2) or were actually smoking, their self-efficacy was significantly lower. In a randomized controlled study measuring self-efficacy at the start and after one year, we found self-efficacy levels concerning healthy food choices and exercise increased, while other self-efficacy scores were not influenced by the intervention. Changes in self-efficacy between baseline and follow up were not associated to changes in vascular risk factors during the study. Because of the small differences between the intervention and control group in the randomized controlled trial concerning self-efficacy score at follow up, we hypothesized that the intervention needs more strongly theory based. Therefore we further developed a self-management intervention, based on Bandura’s social cognitive approach of behavioral change and Wagner’s cooperative problem definition. In evaluating this intervention we saw that cholesterol and blood pressure reduced more in the self-management group compared to the usual care group. Quality of life improved more in the self-management group. To better understand the underlying process we also analyzed the association between self-efficacy and health behavior according to guidelines for vascular risk reduction. Again we found changes in self-efficacy, especially concerning healthy food and exercise between baseline and follow up. The self-efficacy changes were associated to changes in behavior concerning food choices and to exercise behavior. Baseline level of self-efficacy was not associated to any behavioral change. But developing or continuing healthy behavior was associated to higher levels follow up self-efficacy. Self-efficacy and self-management are influenced by social support. Social support is known to be influential in morbidity and mortality of cardiovascular diseases. We measured social support in our vascular population to clarify the influence in vascular risk management. We found associations between social support from having a partner and reduction of BMI and some association between social support and blood glucose. No other associations between social support and vascular risk management were found. Although the changes in risk factors achieved with the self-management intervention were in the right direction, the absolute effect was relatively small. Optimal self-management of vascular risk factors might be too difficult with too little short-term health benefit to compensate for patients’ effort. The achieved behavioural changes are worthwhile in reducing cardiovascular risk on the long term
The Development of Nanostructured TiO2 Sol-Gel Derived Coatings – the Influence of Substrate Preparation Method and Post Treatment of Coatings
No full textThe analysis of literature data and experimental results obtained by the Author of the report clearly showed that further researches shall be devoted to the surface preparation method and characterization of the substrate obtained to check the dependency of morphological features whether they are characteristics of sol or substrates
Sol Grossbard papers 1919
No full textA typescript written while serving in the Signal Corps with the U.S. Expeditionary Forces in Siberia, 1918-1919. It is a critique of the attitudes and policies of the Allies towards Russia and its various political groups which led to the Allies' intervention in Siberia in 1918, and how these shared Russian attitudes toward each of the Allies and contributed to the final outcome of the Allies' venture in Russia. The author also presents his views as to what steps the U.S. should have taken to have enabled a stable democratic Russian government to have evolve
Scrutinizing the importance of surface chemistry versus surface roughness for aluminium / sol-gel film adhesion
No full textThe sol-gel synthesis process is a versatile method used to produce a wide diversity of materials and is being increasingly used as a surface modification method to alter porosity, wettability, catalytic activity, biocompatibility and corrosion performance of underlying substrates. Silane sol–gel films deposited on aluminium and aluminium alloys have been widely studied as chemical conversion coatings and as coupling agent between the substrate and organic layers. This study set out to investigate the effect of the surface chemical treatment prior to sol-gel application on the interfacial adhesion properties of a hybrid sol-gel film. Different surface pre-treatments, including two abrasive treatments and three chemical surface pre-treatments were used and their effect on surface chemistry and surface roughness was assessed. Surfaces were characterized by scanning electron microscopy, x-ray photoelectron spectroscopy, roughness measurements and static contact angles. Cerium nitrate loaded hybrid sol-gel films were deposited and adhesion on commercially pure aluminium was evaluated using pull-off testing. Statistical analysis revealed that, although highest adhesion values were obtained on rougher surfaces, the strongest correlation exists between the surface hydroxyl fraction and adhesion strength.Team Arjan MolTeam Yaiza Gonzalez Garci
From past research experiences looking to the future of sol–gel
No full textAbstract: Based on the outline of the conference that the author held in St. Petersburg for the conferment of the Life Achievement Award, some important steps in the evolution of science and sol–gel technology are revisited through examples taken from his research experiences. The goal is to reconsider what has been done in the past in light of what has been learned in the meantime. Some topics are still current and probably deserve further and more in-depth research, and new ideas for future work may be suggested. Driven by the interest of finding new materials and new fields of application, the sol–gel has evolved from the first studies on simple glass and glass–ceramic systems, to more sophisticated and complex organic–inorganic systems, multifunctional materials, and nanocomposites. [Figure not available: see fulltext.]
Sol–gel one-pot synthesis in soft conditions of mesoporous silica materials ready for drug delivery system
No full textThe present work reveals a new and simple strategy, a one-step sol–gel procedure, to encapsulate a low water-soluble drug in silica mesostructured microparticles and to improve its release in physiological media. The synthesis of these new materials is based on the efficient solubilisation of a poorly water-soluble drug in surfactant micelles (Tween 80, a pharmaceutical excipient) which act as template for the silica network. A strict control of the sol–gel process and the parameters procedure in soft conditions (concentration, pH, temperature) was applied to reach the solubilisation limit of the drug in the micellar solution so as to optimise its encapsulation. Even if this one-pot procedure could appear limited by the low drug loading, it could provide an interesting alternative for the formulation of many recent highly active but very poorly soluble drugs.Nanostructured MaterialsApplied Science
El Sol 4-Ollin de los aztecas
No full textDe acuerdo con Hans Ludendorff (1930), el Tzolkin/Tonalpohualli de 260 días es un ciclo creado para la previsión de eclipses debido a su congruencia con el periodo de paso del Sol por los nodos de la órbita lunar, cada 173.333 días. Esta congruencia divide el ciclo de 260 días en tres partes iguales: 87, 87 y 86 días. Debido a que la duración real del pasaje del Sol por los nodos de la órbita lunar es ligeramente inferior a una tercera parte de un doble tzolkin, i.e. 173.1 en lugar de 173.3 las conjunciones del Sol y los nodos de la órbita lunar regresan un día cada veinte Tun, por lo que una regresión completa en el almanaque de 260 días toma 260 x 20 = 5,200 Tun. Ludendorff asevera que la duración de la Cuenta Larga es el ciclo de corrección del Tzolkin/Tonalpohuali para el cálculo de los eclipses a largo plazo. Las tres zonas de eclipses en el almanaque de 260 días son de 35 días cada una, las restantes son de 52 días cada una y están libres de eclipses. Por lo anterior, cualquier día del Tzolkin que sale de una zona de eclipses estará libre de la ocurrencia de estos durante 1,040 años, hasta que entra en la siguiente zona de eclipses, localizada 52 días después en el almanaque (20 x 52 = 1 ,040). Los nombres de los cinco Soles de la cosmología azteca están ordenados de tal manera que muestran una sucesión lógica de cinco periodos de 1,040 años cada uno. Cada vez que el nombre del día que denomina un Sol entra a una zona de eclipses el siguiente nombre entra a una nueva época de 1,040 años libre de ellos. El inicio del primer Sol toma lugar en el año 3119 a.C., que es el mismo año que inicia la Tabla de Venus en el códice de Dresde; todas las fechas están en conformidad con años bien documentados de la ceremonia del Fuego Nuevo. Esto es lo que se expone en este artículo, con algunos detalles complementarios
El Tlacuache Núm. 915 (2020). 915 Año 19 (2019) enero. El Tlacuache
No full textUna promesa a San Miguel, a través del juego de La Mulita en Alpuyeca por José Cuauhtli Alejandro Medina Romera, Jairo Macedonio Flores, Karen Abigayl Yáñez Rodríguez y Alfredo Balam Castro Zamora
One-pot sonocatalyzed synthesis of sol–gel graphite electrodes containing gold nanoparticles for application in amperometric sensing
No full textWe propose here a one-pot synthetic approach to prepare sol–gel graphite electrodes containing gold nanoparticles (AuNPs). At variance with the traditional synthesis, in which AuNPs are prepared in advance with respect to the silica matrix, they were here obtained directly inside the sol–gel, during its formation. Two reduction methods, namely chemical and thermal reduction, were used to achieve AuNPs starting from a suitable gold precursor, either consisting of NaAuCl 4 or HAuCl 4 . Different experimental parameters were tested in order to direct the synthesis of the material to the characteristics sought, namely Si/Au molar ratio, graphite (g): silane precursor (mL) ratio, chemical nature of the gold precursor and of the reductant, duration and temperature of thermal treatment. Sol–gel was prepared by means of sonocatalysis, in order to reduce the amount of solvent and time necessary for the hydrolysis step. Composition of the material, as well as shape, size and distribution of AuNPs inside the silica matrix was evaluated by spectroscopic and microscopic techniques. Furthermore, electrochemical tests allowed us to ascertain the good conductivity of the composite material and the electrocatalytic activity of AuNPs with respect to glucose and ascorbic acid oxidation. These tests demonstrated that the electrodes obtained by thermal reduction show the best performance in terms of sensitivity for the detection of these analytes, suggesting the possible application of this composite in the field of amperometric sensin
Surface engineering of aerospace aluminium alloys: Understanding alloying effects on chemical pre-treatment and sol-gel coating adhesion
No full textThe sol–gel process is a chemical surface preparation method based on hydrolysis and polycondensation reactions for enhanced adhesion for metallic substrates in adhesive bonding and coating applications. This paper describes an investigation into the effect of the microstructural complexity of two commonly used aerospace aluminium alloys (AAs) 2024-T3 and 7075-T6, on the response to different surface pre-treatments before deposition of the sol-gel coating and subsequent adhesive bonding. Different surface pre-treatments, including two abrasive treatments and three chemical surface pre-treatments were used, and their effect on surface chemistry, wettability and roughness was assessed. Surfaces were characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, profilometry and static contact angles. A hybrid silane sol-gel film was deposited on the differently pre-treated aluminium alloys, an epoxy adhesive was applied and the adhesion properties were evaluated using pull-off testing. The role of the altered physicochemical properties of the pre-treated surfaces was related to the adhesion strength of the sol–gel reinforced epoxy/aluminium interfaces. The microstructural complexity of the aerospace alloys caused non-uniform responses to the pre-treatments, proving the importance of compatibility between material and treatment conditions. Statistical analysis revealed that, despite that overall higher adhesion values were obtained on rougher surfaces, only a strong correlation exists between the surface hydroxyl fraction and adhesion strength. The relation of roughness and water contact angle to interfacial adhesion was found to be non-significant. The findings of this study underscore the critical role of surface pre-treatments and their impact on adhesion strength in aerospace aluminium alloys, providing valuable insights for the effective utilization of sol-gel coatings in adhesive bonding and coating processes.Team Yaiza Gonzalez GarciaTeam Peyman TaheriTeam Shoshan AbrahamiTeam Arjan Mo
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