Crecimiento, fabricación y caracterización de diodos electroluminiscentes basados en pozos cuánticos de InGaN

Teniendo en cuenta la energía del gap de los binarios que forman el temario InGaN (GaN, 3.4 eV; InN, 0.9 eV), es fácil ver que con este material se puede abarcar todo el espectro visible. El objetivo de esta Tesis es estudiar el crecimiento por MBE y las propiedades del InGaN, con la finalidad de fabricar un diodo electroluminiscente eficiente con capa activa compuesta por pozos cuánticos de InGaN con barreras de GaN. La fabricación del LED conlleva también el estudio del dopaje tipo p en el GaN, empleando Magnesio. El crecimiento de capas gruesas de InGaN se ha estudiado como paso previo al de pozos cuánticos. Se ha determinado una temperatura de inicio de evaporación del Indio de la superficie de crecimiento en tomo a 560*C, obteniéndose las mejores capas para temperaturas de substrato ligeramente superiores a ésta y con relación III/V ligeramente superior a la unidad. En el apartado óptico, se ha observado que la amplitud de las fluctuaciones locales en el contenido de Indio en las muestras aumenta cuando se incrementa el contenido promedio de éste. En el crecimiento de pozos cuánticos de InGaN con barreras de GaN, se obtiene los mejores resultados cuando se mantiene fijo el flujo de Galio durante pozo y barrera y se favorece la formación de una capa de Indio segregada a la superficie durante el crecimiento del pozo. A partir de las propiedades de la emisión en cada caso se establece un mayor dominio sobre la energía de la misma de los campos piezoeléctricos en pozos de espesor mayor de 4 nm y de las fluctuaciones de Indio en pozos con éste menor de 3 nm. Con la técnica de crecimiento de pozos cuánticos desarrollada, y empleando cinco pozos de InxGa(1-x)N(-2 nm)/GaN (-5 nm) como capa activa, se han crecido y fabricado dispositivos emitiendo desde el ultravioleta cercano (3.4 eV) hasta el verde (2.4 eV) variando el contenido de Indio de los pozos desde 0 hasta 25 por ciento de Indio. Como método de mejora de los dispositivos se ha estudiado la incorporación del LED a una cavidad resonante centrada en el verde (5 10 nm), realizada con un espejo superior de Aluminio y un reflector de Bragg de AlGaN/GaN como espejo inferior. La potencia de emisión obtenida de este modo es 7 uW a 20 mA, con una intensidad 10 veces mayor que la del LED convencional de la misma longitud de onda. Otro de los métodos de mejora estudiados es la optimización del dopaje de GaN empleando Mg, en el que se ha realizado un estudio en función de la temperatura de célula de Mg, fijando la temperatura de substrato en 690* C. El intervalo útil de temperaturas de la primera queda delimitado por el extremo inferior (-375 *C) por la concentración residual que posean las capas, que ha de ser vencida por el dopaje. El extremo superior (-450' C) queda definido por la generación de defectos en las muestras, lo que puede llevar a un cambio de la polaridad de la capa, produciendo una caída en la incorporación del Mg. Las condiciones óptimas de dopaje se alcanzan para Tmg= 435* C, con una concentración de huecos de 3E 17 cm-3

4to. Congreso Internacional de Ciencia, Tecnología e Innovación para la Sociedad. Memoria académica

Este volumen acoge la memoria académica de la Cuarta edición del Congreso Internacional de Ciencia, Tecnología e Innovación para la Sociedad, CITIS 2017, desarrollado entre el 29 de noviembre y el 1 de diciembre de 2017 y organizado por la Universidad Politécnica Salesiana (UPS) en su sede de Guayaquil. El Congreso ofreció un espacio para la presentación, difusión e intercambio de importantes investigaciones nacionales e internacionales ante la comunidad universitaria que se dio cita en el encuentro. El uso de herramientas tecnológicas para la gestión de los trabajos de investigación como la plataforma Open Conference Systems y la web de presentación del Congreso http://citis.blog.ups.edu.ec/, hicieron de CITIS 2017 un verdadero referente entre los congresos que se desarrollaron en el país. La preocupación de nuestra Universidad, de presentar espacios que ayuden a generar nuevos y mejores cambios en la dimensión humana y social de nuestro entorno, hace que se persiga en cada edición del evento la presentación de trabajos con calidad creciente en cuanto a su producción científica. Quienes estuvimos al frente de la organización, dejamos plasmado en estas memorias académicas el intenso y prolífico trabajo de los días de realización del Congreso Internacional de Ciencia, Tecnología e Innovación para la Sociedad al alcance de todos y todas

Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

XV International Congress of Control Electronics and Telecommunications: "The role of technology in times of pandemic and post-pandemic: innovation and development for strategic social and productive sectors"

La anterior selección, motivados por la aseveración de Manuel Castells -hace casi 20 años ya- que la innovación y la difusión de la tecnología parecía ser la herramienta apropiada para el desarrollo en la era de la información. Este 2020, sin embargo, ante la situación disruptiva que aquejó y aqueja a la sociedad red como una estructura social emergente de la Era de la Información basada en redes de producción, energizadas por el poder y la experiencia; falló y debe reencontrar su rumbo. Es así que los problemas acuciantes, ahora, fueron: la atención sanitaria y la superación de la epidemia de Sars Cov 2; tomó forma la, hasta entonces, visión irrealista de Castells que … no podemos avanzar con nuestros modelos de desarrollo actual, destruyendo nuestro entorno y excluyendo a la mayor parte de la humanidad de los beneficios de la revolución tecnológica más extraordinaria de la historia, sin sufrir una devastadora reacción por parte de la sociedad y la naturaleza. Fue así que el Cuarto Mundo, específicamente, donde la suficiencia de recurso humano, de capital, trabajo, información y mercado -vinculados todos a través de la tecnología- supuso que atendería eficazmente a través de la población que podía por su capacidad hacer uso racional y profesional del conocimiento, las necesidades de la mayoritaria población vulnerable y vulnerada. Por lo anterior, poner en el centro a las personas, en entornos de tarea y trabajo globales hiperconectados combinando espacios físicos, corrientes de información con canales de conexión expeditos, y formando profesionales del conocimiento que asuman y afronten los retos derivados de la transformación digital de empresas, universidades, y organizaciones, pero en condiciones de equidad y sujetos de prosperidad, será el desafío en los escenarios presentes y futuros inmediatos.The previous selection, motivated by the assertion of Manuel Castells -almost 20 years ago- that innovation and diffusion of technology seemed to be the appropriate tool for development in the information age. This 2020, however, in the face of the disruptive situation that afflicted and continues to afflict the network society as an emerging social structure of the Information Age based on production networks, energized by power and experience; He failed and must find his way again. Thus, the pressing problems now were: health care and overcoming the Sars Cov 2 epidemic; Castells' until then unrealistic vision took shape that... we cannot advance with our current development models, destroying our environment and excluding the majority of humanity from the benefits of the most extraordinary technological revolution in history, without suffering a devastating reaction from society and nature. It was thus that the Fourth World, specifically, where the sufficiency of human resources, capital, work, information and market - all linked through technology - meant that it would serve effectively through the population that could, due to its capacity, make rational use. and knowledge professional, the needs of the majority vulnerable and vulnerable population. Therefore, putting people at the center, in hyperconnected global task and work environments, combining physical spaces, information flows with expedited connection channels, and training knowledge professionals who assume and face the challenges derived from the digital transformation of companies, universities, and organizations, but in conditions of equality and subject to prosperity, will be the challenge in the present and immediate future scenarios.Bogot

Global economic burden of unmet surgical need for appendicitis

Background There is a substantial gap in provision of adequate surgical care in many low- and middle-income countries. This study aimed to identify the economic burden of unmet surgical need for the common condition of appendicitis. Methods Data on the incidence of appendicitis from 170 countries and two different approaches were used to estimate numbers of patients who do not receive surgery: as a fixed proportion of the total unmet surgical need per country (approach 1); and based on country income status (approach 2). Indirect costs with current levels of access and local quality, and those if quality were at the standards of high-income countries, were estimated. A human capital approach was applied, focusing on the economic burden resulting from premature death and absenteeism. Results Excess mortality was 4185 per 100 000 cases of appendicitis using approach 1 and 3448 per 100 000 using approach 2. The economic burden of continuing current levels of access and local quality was US $92 492 million using approach 1 and$73 141 million using approach 2. The economic burden of not providing surgical care to the standards of high-income countries was $95 004 million using approach 1 and$75 666 million using approach 2. The largest share of these costs resulted from premature death (97.7 per cent) and lack of access (97.0 per cent) in contrast to lack of quality. Conclusion For a comparatively non-complex emergency condition such as appendicitis, increasing access to care should be prioritized. Although improving quality of care should not be neglected, increasing provision of care at current standards could reduce societal costs substantially

Global economic burden of unmet surgical need for appendicitis

Background There is a substantial gap in provision of adequate surgical care in many low- and middle-income countries. This study aimed to identify the economic burden of unmet surgical need for the common condition of appendicitis. Methods Data on the incidence of appendicitis from 170 countries and two different approaches were used to estimate numbers of patients who do not receive surgery: as a fixed proportion of the total unmet surgical need per country (approach 1); and based on country income status (approach 2). Indirect costs with current levels of access and local quality, and those if quality were at the standards of high-income countries, were estimated. A human capital approach was applied, focusing on the economic burden resulting from premature death and absenteeism. Results Excess mortality was 4185 per 100 000 cases of appendicitis using approach 1 and 3448 per 100 000 using approach 2. The economic burden of continuing current levels of access and local quality was US $92 492 million using approach 1 and$73 141 million using approach 2. The economic burden of not providing surgical care to the standards of high-income countries was $95 004 million using approach 1 and$75 666 million using approach 2. The largest share of these costs resulted from premature death (97.7 per cent) and lack of access (97.0 per cent) in contrast to lack of quality. Conclusion For a comparatively non-complex emergency condition such as appendicitis, increasing access to care should be prioritized. Although improving quality of care should not be neglected, increasing provision of care at current standards could reduce societal costs substantially