ABSTRACT
Atomic layer deposition (ALD) has found significant use in the coating of high-aspect-ratio (HAR) structures. Approaches to model ALD film conformality in HAR structures can generally be classified into diffusion-reaction (DR) models, ballistic transport-reaction (BTR) models and Monte Carlo simulations. This work compares saturation profiles obtained using a DR model and a BTR model. The saturation profiles were compared qualitatively and quantitatively in terms of half-coverage penetration depth, slope at half-coverage penetration depth and adsorption front broadness. The results showed qualitative agreement between the models, except for a section of elevated surface coverage at the end of the structure, 'trunk', observed in the BTR model. Quantitatively, the BTR model produced deeper penetration into the structure, lower absolute values of the slope at half-coverage penetration depth and broader adsorption fronts compared to the DR model. These differences affect the values obtained when extracting kinetic parameters from the saturation profiles.
ABSTRACT
ANTECEDENTES: Las enfermedades cardiovasculares son la principal causa mundial de mortalidad y México no es la excepción. Los datos epidemiológicos obtenidos en 1990 mostraron que los padecimientos cardiovasculares representaron el 19.8% de todas las causas de muerte en nuestro país; esta cifra se incrementó de manera significativa a un 25.5% para 2015. Diversas encuestas nacionales sugieren que más del 60% de la población adulta tiene al menos un factor de riesgo para padecer enfermedades cardiovasculares (obesidad o sobrepeso, hipertensión, tabaquismo, diabetes, dislipidemias). Por otro lado, datos de la Organización Panamericana de la Salud han relacionado el proceso de aterosclerosis como la primer causa de muerte prematura, reduciendo la expectativa de vida de manera sensible, lo que tiene una enorme repercusión social. OBJETIVO: Este documento constituye la guía de práctica clínica (GPC) elaborada por iniciativa de la Sociedad Mexicana de Cardiología en colaboración con la Sociedad Mexicana de Nutrición y Endocrinología, A.C., Asociación Nacional de Cardiólogos de México, A.C., Asociación Mexicana para la Prevención de la Aterosclerosis y sus Complicaciones, A.C., Comité Normativo Nacional de Medicina General, A.C., Colegio Nacional de Medicina Geriátrica, A.C., Colegio de Medicina Interna de México, A.C., Sociedad Mexicana de Angiología y Cirugía Vascular y Endovenosa, A.C., Instituto Mexicano de Investigaciones Nefrológicas, A.C. y la Academia Mexicana de Neurología, A.C.; con el apoyo metodológico de la Agencia Iberoamericana de Desarrollo y Evaluación de Tecnologías en Salud, con la finalidad de establecer recomendaciones basadas en la mejor evidencia disponible y consensuadas por un grupo interdisciplinario de expertos. El objetivo de este documento es el de brindar recomendaciones basadas en evidencia para ayudar a los tomadores de decisión en el diagnóstico y tratamiento de las dislipidemias en nuestro país. MATERIAL Y MÉTODOS: Este documento cumple con estándares internacionales de calidad, como los descritos por el Instituto de Medicina de EE.UU., el Instituto de Excelencia Clínica de Gran Bretaña, la Red Colegiada para el Desarrollo de Guías de Escocia y la Red Internacional de Guías de Práctica Clínica. Se integró un grupo multidisciplinario de expertos clínicos y metodólogos con experiencia en revisiones sistemáticas de la literatura y el desarrollo de guías de práctica clínica. Se consensuó un documento de alcances, se establecieron las preguntas clínicas relevantes, se identificó de manera exhaustiva la mejor evidencia disponible evaluada críticamente en revisiones sistemáticas de la literatura y se desarrollaron las recomendaciones clínicas. Se utilizó la metodología de Panel Delphi modificado para lograr un nivel de consenso adecuado en cada una de las recomendaciones contenidas en esta GPC. RESULTADOS: Se consensuaron 23 preguntas clínicas que dieron origen a sus respectivas recomendaciones clínicas. CONCLUSIONES: Esperamos que este documento contribuya a la mejor toma de decisiones clínicas y se convierta en un punto de referencia para los clínicos y pacientes en el manejo de las dislipidemias y esto contribuya a disminuir la morbilidad y mortalidad derivada de los eventos cardiovasculares ateroscleróticos en nuestro país. BACKGROUND: Cardiovascular diseases are the leading cause of mortality worldwide and Mexico is no exception. The epidemiological data obtained in 1990 showed that cardiovascular diseases represented 19.8% of all causes of death in our country. This figure increased significantly to 25.5% for 2015. Some national surveys suggest that more than 60% of the adult population has at least one risk factor for cardiovascular disease (obesity or overweight, hypertension, smoking, diabetes, dyslipidemias). On the other hand, data from the Pan American Health Organization have linked the process of atherosclerosis as the first cause of premature death, significantly reducing life expectancy, which has enormous social repercussions. OBJECTIVE: This document constitutes the Clinical Practice Guide (CPG) prepared at the initiative of the Mexican Society of Cardiology in collaboration with the Mexican Society of Nutrition and Endocrinology, AC, National Association of Cardiologists of Mexico, AC, Mexican Association for the Prevention of Atherosclerosis and its Complications, AC, National Normative Committee of General Medicine, AC, National College of Geriatric Medicine, AC, College of Internal Medicine of Mexico, AC, Mexican Society of Angiology and Vascular and Endovenous Surgery, AC, Mexican Institute of Research Nephrological, AC and the Mexican Academy of Neurology, A.C.; with the methodological support of the Ibero-American Agency for the Development and Evaluation of Health Technologies, in order to establish recommendations based on the best available evidence and agreed upon by an interdisciplinary group of experts. The objective of this document is to provide evidence-based recommendations to help decision makers in the diagnosis and treatment of dyslipidemias in our country. MATERIAL AND METHODS: This document complies with international quality standards, such as those described by the Institute of Medicine of the USA, the Institute of Clinical Excellence of Great Britain, the Scottish Intercollegiate Guideline Network and the Guidelines International Network. A multidisciplinary group of clinical experts and methodologists with experience in systematic reviews of the literature and the development of clinical practice guidelines was formed. A scope document was agreed upon, relevant clinical questions were established, the best available evidence critically evaluated in systematic literature reviews was exhaustively identified, and clinical recommendations were developed. The modified Delphi Panel methodology was used to achieve an adequate level of consensus in each of the recommendations contained in this CPG. RESULTS: 23 clinical questions were agreed upon which gave rise to their respective clinical recommendations. CONCLUSIONS: We consider that this document contributes to better clinical decision-making and becomes a point of reference for clinicians and patients in the management of dyslipidemias and this contributes to reducing the morbidity and mortality derived from atherosclerotic cardiovascular events in our country.
ABSTRACT
Unparalleled conformality is driving ever new applications for atomic layer deposition (ALD), a thin film growth method based on repeated self-terminating gas-solid reactions. In this work, we re-implemented a diffusion-reaction model from the literature to simulate the propagation of film growth in wide microchannels and used that model to explore trends in both the thickness profile as a function of process parameters and different diffusion regimes. In the model, partial pressure of the ALD reactant was analytically approximated. Simulations were made as a function of kinetic and process parameters such as the temperature, (lumped) sticking coefficient, molar mass of the ALD reactant, reactant's exposure time and pressure, total pressure, density of the grown material, and growth per cycle (GPC) of the ALD process. Increasing the molar mass and the GPC, for example, resulted in a decreasing penetration depth into the microchannel. The influence of the mass and size of the inert gas molecules on the thickness profile depended on the diffusion regime (free molecular flow vs. transition flow). The modelling was compared to a recent slope method to extract the sticking coefficient. The slope method gave systematically somewhat higher sticking coefficient values compared to the input sticking coefficient values; the potential reasons behind the observed differences are discussed.
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Abstract Background: Cardiovascular diseases are the leading cause of mortality worldwide and Mexico is no exception. The epidemiological data obtained in 1990 showed that cardiovascular diseases represented 19.8% of all causes of death in our country. This figure increased significantly to 25.5% for 2015. Some national surveys suggest that more than 60% of the adult population has at least one risk factor for cardiovascular disease (obesity or overweight, hypertension, smoking, diabetes, dyslipidemias). On the other hand, data from the Pan American Health Organization have linked the process of atherosclerosis as the first cause of premature death, significantly reducing life expectancy, which has enormous social repercussions. Objective: This document constitutes the Clinical Practice Guide (CPG) prepared at the initiative of the Mexican Society of Cardiology in collaboration with the Mexican Society of Nutrition and Endocrinology, AC, National Association of Cardiologists of Mexico, AC, Mexican Association for the Prevention of Atherosclerosis and its Complications, AC, National Normative Committee of General Medicine, AC, National College of Geriatric Medicine, AC, College of Internal Medicine of Mexico, AC, Mexican Society of Angiology and Vascular and Endovenous Surgery, AC, Mexican Institute of Research Nephrological, AC and the Mexican Academy of Neurology, A.C.; with the methodological support of the Ibero-American Agency for the Development and Evaluation of Health Technologies, in order to establish recommendations based on the best available evidence and agreed upon by an interdisciplinary group of experts. The objective of this document is to provide evidence-based recommendations to help decision makers in the diagnosis and treatment of dyslipidemias in our country. Material and methods: This document complies with international quality standards, such as those described by the Institute of Medicine of the USA, the Institute of Clinical Excellence of Great Britain, the Scottish Intercollegiate Guideline Network and the Guidelines International Network. A multidisciplinary group of clinical experts and methodologists with experience in systematic reviews of the literature and the development of clinical practice guidelines was formed. A scope document was agreed upon, relevant clinical questions were established, the best available evidence critically evaluated in systematic literature reviews was exhaustively identified, and clinical recommendations were developed. The modified Delphi Panel methodology was used to achieve an adequate level of consensus in each of the recommendations contained in this CPG. Results: 23 clinical questions were agreed upon which gave rise to their respective clinical recommendations. Conclusions: We consider that this document contributes to better clinical decision-making and becomes a point of reference for clinicians and patients in the management of dyslipidemias and this contributes to reducing the morbidity and mortality derived from atherosclerotic cardiovascular events in our country.
