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Estudio de la técnica de irradiación corporal total con arcoterapia volumétrica modulada (VMAT-TBI)
No full textTesis (Magíster en Física Médica)--Pontificia Universidad Católica de Chile, 2024Este estudio implementa la técnica de irradiación corporal total (TBI) mediante terapia de arco volumétrico modulado (VMAT-TBI) y la compara con TBI convencional (cTBI) en un fantoma antropomórfico. Se planificó VMAT-TBI en Monaco 6.1 y se verificó con TLDs, mostrando mejor cobertura de PTV (90.3% vs. 68.9%) y menor dosis pulmonar media (9.4 Gy vs. 10.2 Gy) frente a cTBI, pero con mayor dosis máxima (17.8 Gy vs. 13.7 Gy) y tiempos prolongados. VMAT-TBI es una alternativa viable, aunque con desafíos técnicos y logísticos, destacando su precisión dosimétrica y potencial para protocolos personalizados.Fondequip; Folio de beca: EQM18010
El colorido caso de la sufijación: estudio exploratorio acerca del uso de la sufijación derivativa para las categorías de color en español
No full textTesis (Magíster en Letras con mención en Lingüística)--Pontificia Universidad Católica de Chile, 2025La presente investigación tiene por objetivo principal evaluar la prototipicidad en los sufijos derivativos de las categorías de color en español. Particularmente, se busca observar la relación entre el uso de ciertos sufijos y la percepción que se tiene de la unidad léxica que estos modifican, así como su influencia en los nombres de colores. En otras palabras, se estudia cómo las matizaciones por sufijación influyen en la percepción de los colores en los hablantes, y cómo se construyen, léxicamente, el prototipo y la información cromática de saturación y luminancia. Para esto, se realizaron tres pruebas, dos de evaluación, tanto de tonos como nombres de color, y otra de relaciones. Los resultados demuestran que los sufijos derivativos tienen prototipicidad y se utilizan para informar si un color se acerca o no al centro. A su vez, los resultados dan cuenta de información sobre niveles de saturación y luminancia del tono
Infraestructura multifuncional para la resiliencia hídrica y social de comunidades rurales en zonas áridas: el paisaje cultural de la Quebrada de Totoral Bajo
No full textTesis (Magíster en Arquitectura del Paisaje)--Pontificia Universidad Católica de Chile, 2025La Quebrada de Totoral Bajo, en la región de Atacama, es un sistema hidrográfico caracterizado por la presencia de humedales que han sostenido históricamente su ocupación humana. Este sistema ha permitido el desarrollo agrícola a pequeña escala, preservando atributos culturales y ecológicos hasta la actualidad. Esto lo posiciona como un paisaje de interés patrimonial tanto cultural como ecológico que, sin embargo, se enfrenta al deterioro acelerado debido a la baja rentabilidad de actividades tradicionales como la pesca y la agricultura, y los cambios en las dinámicas productivas y de ocupación que estructuran este paisaje cultural. Además, el estrés hídrico y la fragmentación de los componentes que lo sustentan agravan el riesgo para los modos de vida locales.Esta investigación aborda la quebrada como un paisaje cultural que refleja la interacción entre dinámicas productivas tradicionales y la configuración de un vergel en el desierto costero. Se analiza cómo las prácticas locales pueden integrarse en nuevas infraestructuras para generar usos innovadores y relaciones sostenibles con el territorio. El objetivo es promover resiliencia frente a los desafíos de diversificación económica y los efectos del cambio climático.Mediante un enfoque proyectual, esta tesis busca destacar las características únicas del paisaje y su historia de ocupación, para desarrollar estrategias aplicables a contextos contemporáneos. Se propone el diseño de una infraestructura multifuncional de paisaje que consolide y reconfigure los sistemas locales, ofreciendo soluciones a la permanencia de paisajes culturales campesinos frente a los retos climáticos y socioeconómicos actuales
Parque Área Marina Costera Protegida de Múltiples Usos Isla Grande de Atacama: proyecto para la protección y mediación de un paisaje litoral dinámico
No full textTesis (Magíster en Arquitectura del Paisaje)--Pontificia Universidad Católica de Chile, 2025Ubicada en las costas de la III región de Atacama, al sur de la ciudad de Caldera, se encuentra el Área Marina Costera Protegida de Múltiples Usos Isla Grande de Atacama (AMCP-MU IGA). Declarada en primera instancia en 2004 como Área Marina Costera Protegida de Múltiples Usos (AMCP-MU), es una de las ocho áreas de este tipo existentes en el país y una de las dos presentes en la zona norte de Chile. Este territorio es uno de interés paisajístico debido a su alto valor ecológico, arqueológico y paleontológico. Su riqueza en diferentes esferas lo ha convertido en un punto focal para actividades turísticas, investigativas, productivas, recreativas y deportivas. Sin embargo, estas actividades se realizan sin ningún tipo de regulación y mediación entre ellas, generando fragmentación y degradación del territorio a causa de la fricción generada entre los múltiples usos, afectando directamente la voluntad de protección de este paisaje. La presente investigación busca abordar la problemática existente relacionada con la fricción dada entre los múltiples usos presentes al interior del área protegida y sus efectos en cuanto a la voluntad de protección del territorio, su estado de fragmentación y degradación.Ante esta problemática, se plantea que el proyecto de paisaje posee la capacidad de resolver y mediar aquellas fricciones al posicionarse en las interfaces del territorio; espacios de encuentro entre procesos y dinámicas, pero también de oportunidad.A través de la propuesta de creación de una unidad de parque costero en torno a la ruta, se plantea un sistema interconectado que permite mediar, conservar y rehabilitar el Área Marina Costera Protegida de Múltiples Usos Isla Grande de Atacama para así, poner en valor este paisaje y alcanzar los objetivos de protección de este territorio.2025-06-0
Studying psychiatric diseases using quantitative susceptibility mapping (QSM)
No full textTesis (Doctor in Engineering Sciences)--Pontificia Universidad Católica de Chile, 2025Quantitative Susceptibility Mapping (QSM), a sophisticated MRI-based technique for quantifying brain magnetic susceptibility, has emerged as a valuable tool in exploring neurodegenerative diseases and, more recently, psychiatric disorders such as first-episode schizophrenia, depression, anxiety, and stress. This method allows the measurement of magnetic susceptibilities in various tissues, unveiling associations with diverse phenotypes like body iron, blood assays, diet, and alcohol consumption. Furthermore, investigations into genetic variations across the genome have revealed intriguing links between magnetic susceptibility and clusters of genes responsible for crucial biological functions, including iron regulation, calcium mechanisms, myelin development, and the extracellular matrix.Our primary objective in this thesis is to study associations between psychiatric illnesses and iron content in the gray matter nucleus utilizing QSM. In pursuit of this goal, we conducted two comprehensive analyses involving cohorts of first-episode psychosis patients from Chile and individuals with psychotic-like experiences from the UK biobank. The study scrutinized QSM and R2* differences in gray brain nuclei between patients and controls, employing linear mixed models to explore associations with demographic and clinical variables and genetic factors. Notably, the incorporation of polygenic risk scores (PGS) for psychotic-like experiences in our statistical analyses yielded significant differences in QSM and R2∗ rates between patients and control subjects. Organized into six chapters, our thesis begins with an introduction to the characteristics of psychotic diseases and image biomarkers. Subsequent chapters delve into the theoretical framework linking psychiatric disorders with magnetic susceptibility, detail the methodology employed, present the results, discuss the findings, and conclude with overarching insights. Our findings demonstrate that QSM serves as a powerful tool that may help to elucidate the neurophysiological processes in psychosis and their relationship with iron metabolism. Finally, the proposed methods contribute valuable insights to our current understanding and offer promising image biomarkers for ongoing and future psychiatric research.El Mapeo de Susceptibilidad Cuantitativa (QSM, por sus siglas en inglés), una técnica sofisticada basada en resonancia magnética para cuantificar la susceptibilidad magnética del cerebro. Se ha convertido en una herramienta valiosa en la exploración de enfermedades neurodegenerativas y, más recientemente en trastornos psiquiátricos como el primer episodio de esquizofrenia, depresión, ansiedad y estrés. Este método permite medir la susceptibilidad magnética en varios tejidos, revelando asociaciones con diversos fenotipos como el hierro corporal, los análisis de sangre, la dieta y el consumo de alcohol. Además, las investigaciones sobre las variaciones genéticas en todo el genoma han revelado vínculos intrigantes entre la susceptibilidad magnética y grupos de genes responsables de funciones biológicas cruciales, incluida la regulación del hierro, los mecanismos del calcio, el desarrollo de mielina y la matriz extracelular. Nuestro objetivo principal en esta tesis es estudiar asociaciones entre el contenido de hierro y enfermedades psiquiátricas en núcleos de la materia gris utilizando QSM. Para lograr este objetivo, realizamos dos análisis exhaustivo que involucró cohortes de pacientes con un primer episodio de psicosis de Chile e individuos con experiencias inusuales y psicoticas del Reino Unido. El estudio examino las diferencias usando QSM y R2* en los núcleos cerebrales grises entre pacientes y controles, empleando modelos lineales mixtos para verificar las asociaciones con variables demográficas, clínicas y genéticas. En particular, la incorporación de puntuaciones de riesgo poligénico para experiencias inusuales y psicóticas en nuestros análisis estadísticos arrojo diferencias significativas en las tasas QSM y R2∗ entre pacientes y sujetos de control. Organizada en seis capítulos, nuestra tesis comienza con una introducción a las características de las enfermedades psicóticas y los biomarcadores de imagen conocidos. Los capítulos siguientes profundizan en el marco teórico que vincula los trastornos psiquiátricos con la susceptibilidad magnética, detallan la metodología empleada, presentan los resultados, discuten los hallazgos y concluyen con ideas generales. Nuestros hallazgos demuestran que QSM sirve como una herramienta para dilucidar los procesos neurofisiológicos en la psicosis y su relación con el metabolismo del hierro. Finalmente, los métodos propuestos aportan conocimientos valiosos a nuestra comprensión actual y ofrecen biomarcadores de imágenes prometedores para la investigación psiquiátrica en curso y futura
Coupling Urban Microclimate and Heat and Mass Transfer Green Roof Models to Evaluate the Role of Green Roofs on Urban Heat Island Effect in a Semiarid Climate of Chile
No full textThe Urban Heat Island (UHI) phenomenon is a consequence of urbanization that intensifies citytemperatures, adversely affecting public health, increasing cooling energy demand, and deteriorating air quality. Moreover, heat waves are more frequent and intense, causing thousands of fatalities. Green roofs have emerged as an effective strategy to mitigate these effects, potentially reducing urban temperatures up to 3°C, depending on the climate. However, most urban climate simulation tools do not adequately model the green roof evapotranspiration phenomena and consider green roof vegetation in very simplistic ways
Honey and nectar from Quillaja saponaria Mol. (Quillajaceae): botanical characterization, isolation, identification, and biological evaluation of secondary metabolites
No full textTesis (Doctor en Ciencias de la Agricultura)--Pontificia Universidad Católica de Chile, 2025Honey is a natural sweet food produced by bees, revered for its distinct flavor, nutritional value, and health benefits. Beekeeping in Chile offers a diverse range of honey varieties, many of them unique. Quillay (Quillaja saponaria Molina, soapbark tree) is an endemic tree that grows in the sclerophyllous forests and matorral of central Chile standing as one of the country’s most significant melliferous species due to its high appeal to bees as a nectar source. This study focuses on the characterization and biological evaluation of honey and floral nectaries from Quillaja saponaria Mol. (Quillajaceae). The main objective was to identify a reliable chemical quality indicator of monofloral quillay honey by studying its chemical composition and linking it to its biological properties, emphasizing the antioxidant and antibacterial capacities. The evaluation of its hepatoprotective effects in vitro was also accomplish. Chilean honey samples were analyzed, in an attempt to find quillay honey. The botanical origin of honey samples was determined through the melissopalynology method, and a DNA-based method was performed to identify quillay monofloral honey. Honey samples and quillay nectaries were chemically characterized to identify the phenolic acids and flavonoids through HPLC-DAD, including measuring of total phenolic and flavonoid contents in honey samples. Also, chromatographic methods were used to isolated and identify chemical compounds from quillay honey. Finally, an evaluation of the biological properties of samples, including antioxidant capacity through oxygen radical absorbance capacity (ORAC-FL) and ferric reducing antioxidant power (FRAP) assays, antibacterial activity against pathogenic bacteria, and hepatoprotective potential in HuH-7 liver cell models was carried out. The PCR amplification confirmed the qualitative presence of Quillaja saponaria DNA in samples classified as monofloral based on melissopalynology. Monofloral quillay honey exhibited a higher total phenolic content (TPC) and flavonoid content (TFC) than multifloral honey. Additionally, the Spearman correlation indicates a positive and moderate association between the percentage of quillay pollen and the concentration of TPC in honey samples (R = 0.667), suggesting that phenolic content from quillay tree could contribute to the overall antioxidant capacity of this monofloral honey. The exploration and comparison of phenolic compounds in quillay nectaries and honey samples via HPLC-DAD enable us to propose chrysin and syringic acid as quality indicators for quillay monofloral honey. All honey samples demonstrated effectiveness against S. pyogenes, with a not statistically significant positive Spearman correlation (R = 0.07) between the percentage of quillay pollen and the antibacterial activity observed. In vitro assays in HuH-7 cell cultures revealed hepatoprotective effects of quillay honey extracts, linked to their ability to reduce oxidative damage induced by peroxyl radicals.The findings highlight the unique chemical and biological properties of Quillaja saponaria honey, supporting its potential as a high-value product with therapeutic applications. The research underscores the importance of integrating chemical and botanical analyses for honey authentication and characterization. Future studies are recommended to validate these findings using larger sample sizes and diverse experimental models
Towards a Drought Monitoring, Tracking, and Management Platform Based on Quantitative Indices
No full textDrought is a complex phenomenon that affects the development and use of the country’s water resources. Characterization through indices is critical in planning, management, and decision-making to mitigate the effects of drought, mainly when these are implemented in online platforms for monitoring, warning, and tracking the phenomenon. These tools serve as a basis for implementing a set of measures focused on the short, medium, and long term, oriented to different audiences, and with differentiation of procedures and entities involved depending on the case. This work proposes the technical basis for elaborating preventive drought monitoring in Chile through a visualization platform. Based on a comparative analysis of international tools and the results of a consultation with experts, the relevant characteristics of a system for drought monitoring, follow-up, and management based on standardized drought indexes are analyzed. It is concluded that such a platform should consider multiple drought indices with different levels of severity for their classification. These indices should be automatically calculated using as much information as possible, both from national and international sources, from in-situ gauges as well as from satellite and remote sensing products, and even obtained from modeling. On the other hand, the visualization should be simple, straightforward, and flexible, and the information delivered should provide information on the manifestation of drought in the territory and its short-term forecast
Spiritual care for prevention of psychological disorders in critically ill patients: study protocol of a feasibility randomised controlled pilot trial
No full textIntroduction A significant number of critically ill patients who survive their illness will experience new sequelae or a worsening of their baseline health status following their discharge from the hospital. These consequences may be physical, cognitive and/or psychological and have been labelled postintensive care syndrome (PICS). Prior research has demonstrated that spiritual care aligned with a specific creed during hospitalisation in the intensive care unit (ICU), as part of a comprehensive care plan, may be an effective strategy for preventing psychological sequelae in surviving critically ill patients. However, there is a gap in clinical literature regarding the effectiveness of generalist spiritual care in preventing psychological sequelae associated with PICS. This pilot study aims to explore the feasibility of implementing a generalist spiritual care strategy in the ICU and to evaluate its preliminary effectiveness in preventing anxiety and depression symptoms and post-traumatic stress disorder in critically ill patients. Methods and analysis This is a single-site, feasibility randomised controlled pilot trial of a generalist spiritual care intervention compared with the current standard of care. A total of 30 adults who are critically ill and have undergone invasive mechanical ventilation for a minimum of 72 hours without alterations in consciousness will be randomly assigned to either the spiritual care group or the usual care group at a ratio of 1:1. The primary outcome will be the feasibility and acceptability of the spiritual care strategy in critically ill patients. Secondary aims include evaluating the differences in anxiety and depression symptoms and post-traumatic stress disorder between the spiritual care group and the usual care control group at 3 months after ICU discharge. Subjects will be followed up until 3 months post-ICU discharge. Ethics and dissemination The Ethics Committee for Medical Sciences of Pontificia Universidad Catolica de Chile (#220111005) and the Ethics Committee of Servicio de Salud Metropolitano Sur Oriente approved the study. Pontificia Universidad Cat & oacute;lica de Chile funded the study (project number 105699/DPCC2021). The findings will be widely disseminated through peer-reviewed publications, academic conferences, local community-based presentations, partner organisations and the Chilean Intensive Care Society.Introduction A significant number of critically ill patients who survive their illness will experience new sequelae or a worsening of their baseline health status following their discharge from the hospital. These consequences may be physical, cognitive and/or psychological and have been labelled postintensive care syndrome (PICS). Prior research has demonstrated that spiritual care aligned with a specific creed during hospitalisation in the intensive care unit (ICU), as part of a comprehensive care plan, may be an effective strategy for preventing psychological sequelae in surviving critically ill patients. However, there is a gap in clinical literature regarding the effectiveness of generalist spiritual care in preventing psychological sequelae associated with PICS. This pilot study aims to explore the feasibility of implementing a generalist spiritual care strategy in the ICU and to evaluate its preliminary effectiveness in preventing anxiety and depression symptoms and post-traumatic stress disorder in critically ill patients. Methods and analysis This is a single-site, feasibility randomised controlled pilot trial of a generalist spiritual care intervention compared with the current standard of care. A total of 30 adults who are critically ill and have undergone invasive mechanical ventilation for a minimum of 72 hours without alterations in consciousness will be randomly assigned to either the spiritual care group or the usual care group at a ratio of 1:1. The primary outcome will be the feasibility and acceptability of the spiritual care strategy in critically ill patients. Secondary aims include evaluating the differences in anxiety and depression symptoms and post-traumatic stress disorder between the spiritual care group and the usual care control group at 3 months after ICU discharge. Subjects will be followed up until 3 months post-ICU discharge.Agencia Nacional de Investigacion y Desarroll
Metabolic effects on lung parenchyma of chronic hypoxia secondary to its extrinsic compression in an animal model of congenital diaphragmatic hernia
No full textTesis (Doctor in Medical Sciences)--Pontificia Universidad de Chile, 2024Congenital diaphragmatic hernia (CDH) occurs as a consequence of abnormal development of the transverse septum and incomplete closure of the pleuroperitoneal canals that occurs between the 6th and 10th week of gestation, resulting in herniation of the abdominal viscera through the diaphragmatic defect. The incidence of CDH is 1.93/10.000 births in North America, with an overall 45.89% mortality in the first year of life. In other latitudes of the world, it is similar, with a prevalence, for example, in Canada of 3.38 per 10,000 and in Chile of 2.1 per 10,000 live births, with a mortality rate in the first year of life between 45 and 65%. Despite all the advances of the last 20 years in maternal-fetal medicine, neonatology, and pediatric surgery, mortality remains high at 45-65% in CDH patients. In the prenatal period, timely diagnosis and the attempt to classify fetuses with CDH according to their risk of death and prognosis have been a constant challenge in maternalfetal medicine (MFM). Even advanced ventilatory and circulatory support techniques, such as extracorporeal membrane oxygenation (ECMO), used in the neonatal period have not significantly influenced the mortality rate of CDH.2025-09-3