Inversion charge study in TMO hole-selective contact-based solar cells

© 2023 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.In this article, we study the effect of the inversion charge ( Q inv ) in a solar cell based on the hole-selective characteristic of substoichiometric molybdenum oxide (MoO x ) and vanadium oxide (VO x ) deposited directly on n-type silicon. We measure the capacitance–voltage ( C – V ) curves of the solar cells at different frequencies and explain the results taking into account the variation of the space charge and the existence of Q inv in the c-Si inverted region. The high-frequency capacitance measurements follow the Schottky metal–semiconductor theory, pointing to a low inversion charge influence in these measurements. However, for frequencies lower than 20 kHz, an increase in the capacitance is observed, which we relate to the contribution of the inversion charge. In addition, applying the metal–semiconductor theory to the high-frequency measurements, we have obtained the built-in voltage potential and show new evidence about the nature of the conduction process in this structure. This article provides a better understanding of the transition metal oxide/n-type crystalline silicon heterocontact.The authors would like to acknowledge the CAI de Técnicas Físicas of the Universidad Complutense de Madrid. The authors would also like to thank the Mexican grants program CONACyT for its financial collaboration.Peer ReviewedPostprint (author's final draft

Fabrication of TiOx, by High Pressure Sputtering for Selective Contact in Photovoltaic Cells

Se deposita la versión postprint de la ponenciaIn this work we have studied the behavior of TiO x growth by the unconventional technique of High-Pressure Sputtering (HPS) as an electron selective contact (ESC). This technique shows promising aspects for low-damage and low-temperature deposition, which are relevant criteria for the fabrication of heterojunction solar cells. We explored the deposition of TiO x with a 2-step process. First a thin Ti film is deposited in an Ar atmosphere, immediately the film is oxidized with the aid of an Ar/O 2 plasma at a relatively low temperature (150°C or 200°C). We analyzed the deposited films with XPS, FTIR and TEM measurements. Finally, Cox & Strack (C&S) structures were fabricated to obtain the specific contact resistance of TiOx/c-Si, with this data we compared different deposition processesDepto. de Estructura de la Materia, Física Térmica y ElectrónicaFac. de Ciencias FísicasTRUEpu

Transport mechanisms in hyperdoped silicon solar cells

According to intermediate band (IB) theory, it is possible to increase the efficiency of a solar cell by boosting its ability to absorb low-energy photons. In this study, we used a hyperdoped semiconductor approach for this theory to create a proof of concept of different silicon-based IB solar cells. Preliminary results show an increase in the external quantum efficiency (EQE) in the silicon sub-bandgap region. This result points to sub-bandgap absorption in silicon having not only a direct application in solar cells but also in other areas such as infrared photodetectors. To establish the transport mechanisms in the hyperdoped semiconductors within a solar cell, we measured the J–V characteristic at different temperatures. We carried out the measurements in both dark and illuminated conditions. To explain the behavior of the measurements, we proposed a new model with three elements for the IB solar cell. This model is similar to the classic two-diodes solar cell model but it is necessary to include a new limiting current element in series with one of the diodes. The proposed model is also compatible with an impurity band formation within silicon bandgap. At high temperatures, the distance between the IB and the n-type amorphous silicon conduction band is close enough and both bands are contacted. As the temperature decreases, the distance between the bands increases and therefore this process becomes more limiting.The authors would like to thank the Physical Sciences Research Assistance Centre (CAI de Técnicas Físicas) of the Complutense University of Madrid. This study was partially funded by Project MADRID-PV2 (P2018/EMT-4308), with aid from the Regional Government of Madrid and the ERDF, by the Spanish Ministry of Science and Innovation/National Research Agency (MCIN/AEI) under grants TEC2017- 84378-R, PID2019-109215RB-C41, PID2020-116508RB-I00 and PID2020- 117498RB-I00. Daniel Caudevilla would like to express his thanks for grant PRE2018-083798, provided by the MICINN and the European Social Fund. Francisco Pérez Zenteno would also like to express his thanks for grant 984933, provided by CONACyT (Mexico).Peer ReviewedPostprint (author's final draft

XIII Jornada de Investigación 2022

Los desafíos en las dinámicas económicas, sociales, políticas y psicológicas han puesto de relieve la importancia de involucrar en la enseñanza universitaria actividades que conecten a los estudiantes con las realidades del contexto en el que se desarrollan; simultáneamente, hoy más que nunca se hace evidente que la ciencia, la tecnología y la innovación (CTI) son cruciales para atender los retos sociales, ambientales y económicos de las sociedades actuales. En este contexto, la Jornada de Investigación de la Universidad Católica de Colombia es quizás uno de los espacios institucionales más emblemáticos en el que se visibilizan las actividades en CTI de estudiantes, jóvenes investigadores y profesores, que buscan contribuir a la solución de problemáticas relevantes del entorno. En esta oportunidad, aproximadamente 177 autores y más de 250 espectadores se dieron cita en un escenario virtual que permitió el intercambio de saberes y conocimientos en torno a muchos temas con un lenguaje común: el bienestar de la humanidad y la respuesta efectiva a los retos que tenemos como comunidad. Esta cuarta versión de las Memorias compila las ponencias presentadas en la XIII Jornada de Investigación de 2022, enmarcadas en los tres ejes temáticos de investigación que tiene la Universidad Católica de Colombia: i) Derecho, Cultura y Sociedad, ii) Desarrollo Humano y Sostenible, y iii) Gestión de la Tecnología al Servicio de la Sociedad. Desde la Dirección Central de Investigaciones nos encontramos profundamente agradecidos con todos y cada uno de los participantes, y nos sentimos aún más orgullosos por la calidad de los trabajos presentados. Sea esta la oportunidad para hacer extensiva una felicitación a los autores y a las diferentes Unidades Académicas que, con su compromiso e invaluable labor, permitieron que este evento se desarrollara con éxito.Persona, hospitalidad y construcción de comunidad desde la fraternidad. José Martí: acerca de la libertad en la condición humana. Moda, imagen y alimentación: una tríada para el bien y para el mal. Lecciones de la pandemia de covid-19: conflictos entre la protección jurídica de las patentes farmacéuticas y el interés general de la salud pública. Psicología y sexualidad: propuesta para la formación de psicólogos colombianos. Estrategias para el desarrollo de herramientas que fomentan el aprendizaje para el reconocimiento y la apropiación del patrimonio cultural. Análisis descriptivo de relatos honestos y deshonestos por medio del sistema de evaluación global. El uso de la herramienta LIWC para el estudio de relatos altruistas y prosociales. ¿De qué manera influyen las redes sociales como medio de información en campañas políticas?. Sistema de Seguridad Social en Colombia: una crisis deficitaria que se refuerza con el tiempo. Turismo sexual en menores de edad: problemática endémica en el territorio colombiano. Transgresión de los derechos humanos en relación con los asesinatos de líderes sociales en el Estado colombiano. El nuevo escenario para la procedencia de la eutanasia en Colombia: una mirada desde los derechos humanos. Protección de los derechos de la infancia frente a los grupos al margen de la ley. El derecho a un nivel de vida adecuado: un enfoque hacia el desplazamiento forzado de los pueblos indígenas. Tráfico de órganos humanos: delito transnacional que vulnera los derechos humanos y su regulación en el marco jurídico colombiano. Transgresión de los derechos a la vida y la libertad en el sistema penitenciario como consecuencia de la violencia social. Acceso a la justicia colombiana en tiempos de SARS-CoV-2. Prioridades para la administración de justicia penal en Colombia: ¿balanceando espectáculo e indicadores de eficacia? Desarrollo de competencias para la investigación en neuropsicología: experiencia del semillero experimental. La dificultad al ingreso de los centros geriátricos. Principio de realidad sobre la formalidad constitucional en contrato verbal laboral en un satélite del Consultorio Jurídico de la Universidad Católica de Colombia. La pena de muerte en colisión con los derechos fundamentales. Maternidad subrogada: objetificación y vulneración de los derechos de la mujer. Una dieta inconsciente hacia el vegetarianismo. Sistema de evaluación del bienestar gerontológico para un diseño arquitectónico sostenible. Caso de estudio: hogar de paso San Francisco de Asís, Villavicencio, Meta. Revisión sistemática interacción líder-colaborador: futuras investigaciones. Análisis conceptual del talento académico desde los modelos teóricos que lo sustentan. Identificación de potenciales factores de riesgo suicida: una mirada contextual. La regulación emocional en tiempos de coronavirus. GEES: Guía de Evaluación de Edificaciones Sostenibles, vivienda de interés social, clima cálido húmedo. Estructura proyectual y sostenible para el diseño y desarrollo de un modelo de vivienda de madera en San Andrés y Providencia, Colombia. Innovación social para la gestión territorial. Construcción de material didáctico para el entrenamiento en habilidades de regulación emocional e interpersonales dirigidas a poblaciones expuestas a situaciones de violencia política. Alternativas sostenibles de modelos de desarrollo industrial. La ruralidad dentro de los procesos del desarrollo local en Usme. Se ha dejado de dibujar arquitectura con las manos. Calidad de vida, bienestar y felicidad en el trabajo: una revisión sistemática de la literatura científica, 2011-2021. Autonomía, autorregulación y educación moral: reflexiones desde la psicología del desarrollo moral. Características de los niños, niñas y adolescentes expuestos a contextos de conflicto armado en Colombia. Revisión bibliométrica de artículos sobre la crianza en niños, niñas y adolescentes colombianos. Narrativas sociales en el proceso de cualificación de lo público La habitación exterior como extensión de la vivienda. Utilización de nanopartículas magnéticas Fe3O4 y ozono para la degradación/eliminación de azul de metileno en agua residual textil. Estudio paramétrico de un modelo numérico Fem de un ensayo CBR. ¿Cómo construir identidad de manera incluyente a partir del reconocimiento de patrimonio cultural construido?. Veracidad de los resultados del ensayo de penetración dinámica de CONO(PDC). Análisis de texto a partir del procesamiento de lenguaje natural para identificar sintomatología depresiva en redes sociales. Análisis de texto para la detección de depresión en comentarios de usuarios de la red social Instagram. Diseño y desarrollo de un videojuego para evaluar la interacción de las redes atencionales en la sintomatología depresiva. Herramienta tecnológica para el apoyo en la detección de sintomatología ansiosa en jóvenes. Optimización del despliegue de aplicaciones web a partir de computación en nube sin servidor. Prototipo alfa de un videojuego serio para el apoyo en la detección de sintomatología depresiva en adultos jóvenes. La importancia de la visualización de datos en la era del Big Data y sus herramientas. Prototipo de sensor para el registro electroencefalográfico. Prototipo de un algoritmo basado en inteligencia artificial para el apoyo a especialistas en el diagnóstico del Alzheimer. Evaluación posocupacional del confort térmico en la vivienda social: análisis de una revisión sistemática prisma desde el diseño resiliente. Inteligencia artificial, problema u oportunidad para el Derecho. Impacto en el empleo en relación con las TIC y la inteligencia artificial. Neuroprivacidad. El test de asociación implícita, un paradigma que permite abordar nuestras actitudes inconscientes. ¿Cuál es el límite del uso de las tecnologías frente al derecho de información y de la libre expresión?. Tendencias de fijación de precios basados en el valor: un análisis desde la minería de datos. Recorrido virtual de la Universidad Católica de Colombia Sede Claustro para la inducción de estudiantes y docentes. Introducción a la bioarquitectura del paisaje, cartilla Paisaje, ambiente y tecnología. Descripción plan piloto (Choachí). Caracterización de las habilidades específicas para el reconocimiento del patrimonio cultural – Borde urbano sur oriental de Bogotá. Videojuego para estimular la memoria episódica en pacientes con deterioro cognitivo leve: validación de contenido. CONCLUSIONESTercera edició

Reproducibility of fluorescent expression from engineered biological constructs in E. coli

We present results of the first large-scale interlaboratory study carried out in synthetic biology, as part of the 2014 and 2015 International Genetically Engineered Machine (iGEM) competitions. Participants at 88 institutions around the world measured fluorescence from three engineered constitutive constructs in E. coli. Few participants were able to measure absolute fluorescence, so data was analyzed in terms of ratios. Precision was strongly related to fluorescent strength, ranging from 1.54-fold standard deviation for the ratio between strong promoters to 5.75-fold for the ratio between the strongest and weakest promoter, and while host strain did not affect expression ratios, choice of instrument did. This result shows that high quantitative precision and reproducibility of results is possible, while at the same time indicating areas needing improved laboratory practices.Peer reviewe

Evolution over Time of Ventilatory Management and Outcome of Patients with Neurologic Disease∗

OBJECTIVES: To describe the changes in ventilator management over time in patients with neurologic disease at ICU admission and to estimate factors associated with 28-day hospital mortality. DESIGN: Secondary analysis of three prospective, observational, multicenter studies. SETTING: Cohort studies conducted in 2004, 2010, and 2016. PATIENTS: Adult patients who received mechanical ventilation for more than 12 hours. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Among the 20,929 patients enrolled, we included 4,152 (20%) mechanically ventilated patients due to different neurologic diseases. Hemorrhagic stroke and brain trauma were the most common pathologies associated with the need for mechanical ventilation. Although volume-cycled ventilation remained the preferred ventilation mode, there was a significant (p < 0.001) increment in the use of pressure support ventilation. The proportion of patients receiving a protective lung ventilation strategy was increased over time: 47% in 2004, 63% in 2010, and 65% in 2016 (p < 0.001), as well as the duration of protective ventilation strategies: 406 days per 1,000 mechanical ventilation days in 2004, 523 days per 1,000 mechanical ventilation days in 2010, and 585 days per 1,000 mechanical ventilation days in 2016 (p < 0.001). There were no differences in the length of stay in the ICU, mortality in the ICU, and mortality in hospital from 2004 to 2016. Independent risk factors for 28-day mortality were age greater than 75 years, Simplified Acute Physiology Score II greater than 50, the occurrence of organ dysfunction within first 48 hours after brain injury, and specific neurologic diseases such as hemorrhagic stroke, ischemic stroke, and brain trauma. CONCLUSIONS: More lung-protective ventilatory strategies have been implemented over years in neurologic patients with no effect on pulmonary complications or on survival. We found several prognostic factors on mortality such as advanced age, the severity of the disease, organ dysfunctions, and the etiology of neurologic disease

Effects of pre-operative isolation on postoperative pulmonary complications after elective surgery: an international prospective cohort study an international prospective cohort study

We aimed to determine the impact of pre-operative isolation on postoperative pulmonary complications after elective surgery during the global SARS-CoV-2 pandemic. We performed an international prospective cohort study including patients undergoing elective surgery in October 2020. Isolation was defined as the period before surgery during which patients did not leave their house or receive visitors from outside their household. The primary outcome was postoperative pulmonary complications, adjusted in multivariable models for measured confounders. Pre-defined sub-group analyses were performed for the primary outcome. A total of 96,454 patients from 114 countries were included and overall, 26,948 (27.9%) patients isolated before surgery. Postoperative pulmonary complications were recorded in 1947 (2.0%) patients of which 227 (11.7%) were associated with SARS-CoV-2 infection. Patients who isolated pre-operatively were older, had more respiratory comorbidities and were more commonly from areas of high SARS-CoV-2 incidence and high-income countries. Although the overall rates of postoperative pulmonary complications were similar in those that isolated and those that did not (2.1% vs 2.0%, respectively), isolation was associated with higher rates of postoperative pulmonary complications after adjustment (adjusted OR 1.20, 95%CI 1.05–1.36, p = 0.005). Sensitivity analyses revealed no further differences when patients were categorised by: pre-operative testing; use of COVID-19-free pathways; or community SARS-CoV-2 prevalence. The rate of postoperative pulmonary complications increased with periods of isolation longer than 3 days, with an OR (95%CI) at 4–7 days or ≥ 8 days of 1.25 (1.04–1.48), p = 0.015 and 1.31 (1.11–1.55), p = 0.001, respectively. Isolation before elective surgery might be associated with a small but clinically important increased risk of postoperative pulmonary complications. Longer periods of isolation showed no reduction in the risk of postoperative pulmonary complications. These findings have significant implications for global provision of elective surgical care. We aimed to determine the impact of pre-operative isolation on postoperative pulmonary complications after elective surgery during the global SARS-CoV-2 pandemic. We performed an international prospective cohort study including patients undergoing elective surgery in October 2020. Isolation was defined as the period before surgery during which patients did not leave their house or receive visitors from outside their household. The primary outcome was postoperative pulmonary complications, adjusted in multivariable models for measured confounders. Pre-defined sub-group analyses were performed for the primary outcome. A total of 96,454 patients from 114 countries were included and overall, 26,948 (27.9%) patients isolated before surgery. Postoperative pulmonary complications were recorded in 1947 (2.0%) patients of which 227 (11.7%) were associated with SARS-CoV-2 infection. Patients who isolated pre-operatively were older, had more respiratory comorbidities and were more commonly from areas of high SARS-CoV-2 incidence and high-income countries. Although the overall rates of postoperative pulmonary complications were similar in those that isolated and those that did not (2.1% vs 2.0%, respectively), isolation was associated with higher rates of postoperative pulmonary complications after adjustment (adjusted OR 1.20, 95%CI 1.05–1.36, p = 0.005). Sensitivity analyses revealed no further differences when patients were categorised by: pre-operative testing; use of COVID-19-free pathways; or community SARS-CoV-2 prevalence. The rate of postoperative pulmonary complications increased with periods of isolation longer than 3 days, with an OR (95%CI) at 4–7 days or ≥ 8 days of 1.25 (1.04–1.48), p = 0.015 and 1.31 (1.11–1.55), p = 0.001, respectively. Isolation before elective surgery might be associated with a small but clinically important increased risk of postoperative pulmonary complications. Longer periods of isolation showed no reduction in the risk of postoperative pulmonary complications. These findings have significant implications for global provision of elective surgical care

Global variation in postoperative mortality and complications after cancer surgery: a multicentre, prospective cohort study in 82 countries

© 2021 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY-NC-ND 4.0 licenseBackground: 80% of individuals with cancer will require a surgical procedure, yet little comparative data exist on early outcomes in low-income and middle-income countries (LMICs). We compared postoperative outcomes in breast, colorectal, and gastric cancer surgery in hospitals worldwide, focusing on the effect of disease stage and complications on postoperative mortality. Methods: This was a multicentre, international prospective cohort study of consecutive adult patients undergoing surgery for primary breast, colorectal, or gastric cancer requiring a skin incision done under general or neuraxial anaesthesia. The primary outcome was death or major complication within 30 days of surgery. Multilevel logistic regression determined relationships within three-level nested models of patients within hospitals and countries. Hospital-level infrastructure effects were explored with three-way mediation analyses. This study was registered with ClinicalTrials.gov, NCT03471494. Findings: Between April 1, 2018, and Jan 31, 2019, we enrolled 15 958 patients from 428 hospitals in 82 countries (high income 9106 patients, 31 countries; upper-middle income 2721 patients, 23 countries; or lower-middle income 4131 patients, 28 countries). Patients in LMICs presented with more advanced disease compared with patients in high-income countries. 30-day mortality was higher for gastric cancer in low-income or lower-middle-income countries (adjusted odds ratio 3·72, 95% CI 1·70–8·16) and for colorectal cancer in low-income or lower-middle-income countries (4·59, 2·39–8·80) and upper-middle-income countries (2·06, 1·11–3·83). No difference in 30-day mortality was seen in breast cancer. The proportion of patients who died after a major complication was greatest in low-income or lower-middle-income countries (6·15, 3·26–11·59) and upper-middle-income countries (3·89, 2·08–7·29). Postoperative death after complications was partly explained by patient factors (60%) and partly by hospital or country (40%). The absence of consistently available postoperative care facilities was associated with seven to 10 more deaths per 100 major complications in LMICs. Cancer stage alone explained little of the early variation in mortality or postoperative complications. Interpretation: Higher levels of mortality after cancer surgery in LMICs was not fully explained by later presentation of disease. The capacity to rescue patients from surgical complications is a tangible opportunity for meaningful intervention. Early death after cancer surgery might be reduced by policies focusing on strengthening perioperative care systems to detect and intervene in common complications. Funding: National Institute for Health Research Global Health Research Unit

Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study

© 2022 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 licenseBackground: Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide. Methods: A multimethods analysis was performed as part of the GlobalSurg 3 study—a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital. Findings: Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3·85 [95% CI 2·58–5·75]; p<0·0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63·0% vs 82·7%; OR 0·35 [0·23–0·53]; p<0·0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer. Interpretation: Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised. Funding: National Institute for Health and Care Research