Proyectos

Overview: Mechanical wave propagation physics is related to traumatic brain injury mechanisms. For instance, nonlinear shear waves can form in the brain progressively with propagation, amplifying the acceleration locally. This phenomenon is compatible with axonal brain injury in which the lesions are localized far from the impact region. Within the brain, not only shear waves propagate. Especially when considering the brain is full of folds and surfaces, including the gray-white matter interface, which can be seen in Fig. 1. The abundance of interfaces or surfaces makes us hypothesize that surface waves might be crucial for describing the biomechanics of traumatic brain injury. The surface waves are named after the nature of the interface. A wave propagating in a solid-vacuum interface is known as a Rayleigh wave, a wave propagating in a solid-fluid interface is known as a Scholte wave, and a wave propagating in a solid-solid interface is known as a Stoneley wave. This last might propagate within an interface formed by two types of soft tissue. An example of this is the interfaces formed by the white and gray matter in the brain (see Fig. 1). Surface waves, although confined to a surface, can penetrate up to a wavelength. In the context of soft tissues, the typical frequencies of elastic waves that propagate are in the range of 10 to 300 Hz. At these frequencies, the wavelengths are on the order Figure 1: Section of a temporal of centimeters, creating the necessity of studying these waves at brain lobe. Image obtained from depth. Surface waves are not explored sufficiently in incompressible soft the visible human project [1]. solids yet. We recently measured Scholte waves at depth in these materials. However, we are not aware of measurements of Stoneley waves at depth in incompressible soft solids like brain matter or gelatin. The lack of this experimental evidence is due to the challenges of measuring deformation in opaque materials without disrupting the medium. Thus, the general objective of this proposal is to detect, describe and characterize the propagation of Stoneley waves in interfaces formed by two incompressible tissue-mimicking materials using Ultrafast Ultrasound elastography-related techniques. Methodology: Advanced ultrasound imaging techniques implemented on a highly customized ultrasound imaging platform designed for high frame-rate imaging will be used to characterize fundamental Stoneley wave physics propagating at the interfaces between two soft solids. We first will perform experiments in flats and simple interfaces to obtain the parameter space (shear modulus, density, and prestress) in which planar Stoneley waves exist. Then, we will explore the effects of the bonding condition between the two mediums on the dispersion relation. Third, we will investigate the interaction of the shape of the interface on the wave propagation, and lastly, we will intend to propagate Stonely waves into 3D inclusions. These observations will be achieved with a number of steps that integrate advancements in ultrasound imaging, algorithms that measure the deformation, and modeling. Custom two-dimensional and three-dimensional imaging sequences, designed for displacement tracking, will be implemented for a dedicated Linear and Matrix array transducer that has 128 or 1024 elements and can reach a spatial resolution of 200microns at a very high framerate in the order of 10000 frames per second (2D or 3D frames respectively). Expected results: The results of this proposal will elucidate the conditions that the two soft solids need to propagate Stoneley waves. These conditions refer to the combination of mechanical properties of the materials, such as shear modulus and density, and the prestress field needed. We expect to establish the effect that the bonding condition between the two soft solids has on the nature of the Stoneley wave. In particular, we will monitor how the Stoneley wave speed and dispersion change with different bonding conditions. We believe this phenomenology has implications in imaging technology, tumor diagnosis, and brain injury biomechanics.

Objetivo general: Instalar una editorial cooperativa en la región de O’Higgins sustentada a partir de la comercialización de productos y servicios educativos desarrollados en base a evidencia científica, que permitan implementar el aprendizaje basado en juegos y que consideran la diversidad del aula. Esta propuesta incluye la instalación de un laboratorio de prototipado y producción, además del desarrollo de un paquete de productos y servicios educativos cuya comercialización permite sustentar la editorial cooperativa. 5.4.1. Objetivo Específico 1 (Editorial Cooperativa) Coordinar una red de emprendedores del área educativa para establecer una editorial cooperativa para la Región de O’Higgins para desarrollar y comercializar productos y servicios educativos lúdicos, de base científica y carácter inclusivo. Funciona bajo un modelo de cooperativa cuyos miembros son emprendedores localizados en la región de O’Higgins con interés en innovación educativa, trabajando bajo el principio de ayuda mutua. 5.4.2. Objetivo Específico 2 (Diagnóstico de Productos) Diagnosticar las necesidades de productos y servicios educativos para promover la calidad de los aprendizajes en los primeros cursos de educación básica en la región de O’Higgins. Identifica tópicos en matemáticas y lenguaje que presentan dificultades al momento de su enseñanza, describe la diversidad de estudiantes en escuelas municipales e indaga métodos de comercialización comunes. 5.4.3. Objetivo Específico 3 (Laboratorio de prototipado y Manufactura) Instalar en la Universidad de O’Higgins un laboratorio para elaborar prototipos de juegos de mesa educativos y producirlos en pequeña escala. Se adquiere maquinaria, equipamientos e insumos necesarios para que el Laboratorio de Aprendizaje Matemático (LAM) pueda prototipar juegos de mesa y, en conjunto con la Fábrica Digital O’Higgins (FabLab), producirlos con alta calidad y en pequeña escala de manera eficiente (30-100 ejemplares). 5.4.4. Objetivo Específico 4 (Desarrollo de Productos) Realizar el diseño, prototipado y manufactura de un paquete de productos educativos para fortalecer las áreas de matemática y lenguaje en los primeros años de educación básica. Diseñados en base a ciencias del aprendizaje, estos productos permiten desarrollar aprendizajes en base a juegos y actividades lúdicas considerando la diversidad de estudiantes en el aula. 5.4.5. Objetivo Específico 5 (Capacitación y Servicios) Generar un programa de capacitación para certificar a los emprendedores educativos para que provean servicios que acompañan a los productos educativos ofrecidos por la editorial. Este programa certifica que el emprendedor es experto en la aplicación de los productos educativos desarrollados. Este certificado habilita a los miembros de la editorial para ofrecer estos servicios en el mercado educativo.

Frailty is increasingly becoming an important public health challenge worldwide because it is associated with older age, and with adverse outcomes such as reduced quality of life, increased mortality rates, hospitalizations, falls, depression, and dementia. Frailty is defined as dynamic state affecting an individual who experiences losses in one or more domains of human functioning (physical, psychological, social) that are caused by the influence of a range of variables, and which increases the risk of adverse outcomes. This more integral conceptual definition promotes the collaboration of scientists, social and behavioral professionals as well as clinicians from diverse specialties. In this proposal an interdisciplinary group (Biochemistry, Geriatric, Occupational Therapist, Kinesiologist, social worker, bioengineer, statistician among others) aims to evaluate frailty in Chile with a biopsychosocial approach with the final purpose to identify and manage frailty while taking into consideration all the dimensions. Additionally, we aim to design a multidomain personalized person-base intervention for a healthy aging that can uncover a circulating microRNA biomarker panel that can allow an early-detection of frailty, leading to a new multidimensional geriatric assessment. We propose the following hypothesis: A personalized multidimensional training program reduces the frailty prevalence, increasing adherence and participation in the program among community-living older adults. This intervention will be paralleled by a distinctive miRNA profile reflecting the multiple domains of frailty, as well as improvements in diverse psychosocial traits.

This project aims to investigate how structural modifications of a dicationic derivative of azobenzene can affect the drug release and load capacity of its photoactive molecular aggregate. To evaluate this, three types of structural modifications are proposed. First, the introduction of functional groups on the photoactive nucleus of dicationic azobenzene is expected to shift the absorption band of the molecular photoswitch. Second, the replacement of the fluorescent organic cations over the structure of the molecular photoswitch, which confer luminescent and amphipathic properties to the system. And third, the modification of the length of the chains over the molecular photoswitch could change the aggregate size. To determine whether these potential modifications can modulate the light-induced release activity of the photoswitchable aggregate, an enzyme inhibitor will be loaded and released by illumination in the presence of the enzyme. Under this scenario, any modification of the enzymatic activity will be correlated with the drug's photorelease.

The proposal focuses on understanding the neuro-vascular aging mechanisms associated with alterations in fetal growth by intrauterine hypoxia using molecular biology and physiology as an area. The aim of the study is to demonstrate that impaired fetal growth conditions are associated with epigenetic programming of aging-related DNA methylation, chromatin remodeling, and miRNA-omic profile of junctional complex genes in the neuroendothelium, which can alter BBB integrity and permeability, increasing cerebral damage which impacts the juvenile and adulthood neurocognitive function.

Overview: Mechanical wave propagation physics is related to traumatic brain injury mechanisms. For instance, nonlinear shear waves can form in the brain progressively with propagation, amplifying the acceleration locally. This phenomenon is compatible with axonal brain injury in which the lesions are localized far from the impact region. Within the brain, not only shear waves propagate. Especially when considering the brain is full of folds and surfaces, including the gray-white matter interface, which can be seen in Fig. 1. The abundance of interfaces or surfaces makes us hypothesize that surface waves might be crucial for describing the biomechanics of traumatic brain injury. The surface waves are named after the nature of the interface. A wave propagating in a solid-vacuum interface is known as a Rayleigh wave, a wave propagating in a solid-fluid interface is known as a Scholte wave, and a wave propagating in a solid-solid interface is known as a Stoneley wave. This last might propagate within an interface formed by two types of soft tissue. An example of this is the interfaces formed by the white and gray matter in the brain (see Fig. 1). Surface waves, although confined to a surface, can penetrate up to a wavelength. In the context of soft tissues, the typical frequencies of elastic waves that propagate are in the range of 10 to 300 Hz. At these frequencies, the wavelengths are on the order Figure 1: Section of a temporal of centimeters, creating the necessity of studying these waves at brain lobe. Image obtained from depth. Surface waves are not explored sufficiently in incompressible soft the visible human project [1]. solids yet. We recently measured Scholte waves at depth in these materials. However, we are not aware of measurements of Stoneley waves at depth in incompressible soft solids like brain matter or gelatin. The lack of this experimental evidence is due to the challenges of measuring deformation in opaque materials without disrupting the medium. Thus, the general objective of this proposal is to detect, describe and characterize the propagation of Stoneley waves in interfaces formed by two incompressible tissue-mimicking materials using Ultrafast Ultrasound elastography-related techniques. Methodology: Advanced ultrasound imaging techniques implemented on a highly customized ultrasound imaging platform designed for high frame-rate imaging will be used to characterize fundamental Stoneley wave physics propagating at the interfaces between two soft solids. We first will perform experiments in flats and simple interfaces to obtain the parameter space (shear modulus, density, and prestress) in which planar Stoneley waves exist. Then, we will explore the effects of the bonding condition between the two mediums on the dispersion relation. Third, we will investigate the interaction of the shape of the interface on the wave propagation, and lastly, we will intend to propagate Stonely waves into 3D inclusions. These observations will be achieved with a number of steps that integrate advancements in ultrasound imaging, algorithms that measure the deformation, and modeling. Custom two-dimensional and three-dimensional imaging sequences, designed for displacement tracking, will be implemented for a dedicated Linear and Matrix array transducer that has 128 or 1024 elements and can reach a spatial resolution of 200microns at a very high framerate in the order of 10000 frames per second (2D or 3D frames respectively). Expected results: The results of this proposal will elucidate the conditions that the two soft solids need to propagate Stoneley waves. These conditions refer to the combination of mechanical properties of the materials, such as shear modulus and density, and the prestress field needed. We expect to establish the effect that the bonding condition between the two soft solids has on the nature of the Stoneley wave. In particular, we will monitor how the Stoneley wave speed and dispersion change with different bonding conditions. We believe this phenomenology has implications in imaging technology, tumor diagnosis, and brain injury biomechanics.

The project covers the following topics: vibrations, multiphase flow, and pipes. All of them are strongly related to Mechanical Engineering and its applications.

Ocean Island Volcanoes (OIVs) and seamounts are one of the most common, prominent and rapidly formed but least studied (from a geological/volcanological point of view) features on Earth. OIVs, which represent only the summit section of a much larger volcanic edifice rising up from the sea floor, are highly vulnerable to geological hazards such as volcanism, seismic activity, mass wasting (caldera formation), landslides and rockfalls, and tsunamis. Specifically, a volcanic eruption on an OIV can mainly have a substantial impact on the local population, infrastructure and economy. It is then essential understand the characteristic behaviour and the ages of the recent eruptions of the volcano to enhance the capacity to identify future geological hazard processes such as eruptions, tsunamis, etc. In other words, to forecast how a volcano will behave, it is essential to identify, map and analyse the deposits from past eruptions and determine the ages of those deposits. However, this becomes more challenging on Ocean Island Volcanoes that have not experienced recent eruptions, such as Easter Island (Chile), but which may still pose a significant risk of future eruption. This proposal focuses on Easter Island (Rapa Nui or Isla de Pascua), an isolated southeast Pacific island with 7.750 inhabitants, that receives more than 100.000 tourists per year. This island has been catalogued as one of the 92 active volcanos of Chile by the Chilean mining and geological service, occupying the 46th position in its Volcanic Risk ranking. It was included taking into account the recent activity focused on Terevaka volcano and its peripheral vents and other factors as the population and infrastructures exposure and its high amount of visitors per year. Nevertheless, there is still a lack of robust geochronology and volcano-stratigraphy and morphometry for Easter Island, especially for these most recent eruptions. Therefore, a comprehensive study of its Holocene eruptions regarding their styles, a more accurate age determination, and a well identification of submarine volcanic centres around the island is still pending to evaluate its potential volcanic hazard. The main aim of this project is to identify and study the most recent eruptions of Easter Island, both onshore and offshore. This will allow understanding how and when they took place in terms of volume, diverse morphometric parameters, styles and their ages which will verify if the island is still active. To identify and characterize the style of the most recent eruptions (Holocene- last 11.700 Kyr) on the island it is planned to conduct geomorphologic and morhometryc analyses of subaerial and submarine recent volcanic deposits with and integrated onshore/offshore approach. Also, volcano-stratigraphy for the most recent cones and associated deposits onshore, with special attention to those hydrovolcanic eruptions will be analysed. To determine the number of Holocene eruptions on the island, 14C (for charcoal), 40Ar/39Ar (for rocks) techniques will be used. Moreover, we will identify and date tephras of lacustrine sedimentary records of the Rano Raraku, Rano Kao lakes and the Rano Aroi peat bog related to recent eruptions. A likely future eruption on the island or near its coasts would have negative and serious consequences; therefore, it is essential to undertake this scientific research aimed at improving the knowledge of the processes and their potential impacts. Furthermore, this study will also contribute to understanding the overall evolution of an interoceanic volcanic island whose results can be compared with other more studied OIVs in the world. In addition, this project will support undergraduate and graduate students, for whom this study will comprise most of their dissertation research, being an extraordinary opportunity for them. Moreover, this study will foster ongoing international collaboration, providing a pipeline for future student and faculty exchange, and will promote outreach educational experiences for the community, as well as more specialized seminars.

The world's transition to using cleaner energy sources to address climate change has led to a sharp rise in the demand for base and precious metals. Consequently, discovering new ore deposits to meet this growing demand and prevent supply shortages has emerged as one of the greatest challenges of the 21st century. Discovery of new magmatic-hydrothermal ore deposits can be improved based on a fundamental understanding of the geological processes that control the flux and focusing of ore-constituting elements in the Earth’s crust, and by identifying the differences between the bulk-rock and mineral chemistry of ore-forming and ordinary—barren—granitoids. Large metal anomalies in the Earth’s upper crust, such as porphyry copper-(molybdenum) deposits (PCDs), occur in intimate association with oxidized and water-rich arc magmatism in subduction zones. However, these deposits occur in restricted crustal domains and form in response to specific tectono-magmatic events, indicating that not all arc magmas have the same ore-forming potential. Understanding why only some magmas produced large PCDs while most other arc magmas remain barren is a fundamental scientific question and key to developing efficient exploration strategies. The volatile element composition of arc magmas, including water, sulfur, and halogens such as chlorine and fluorine, as well as their oxygen fugacity, exert a critical control on their ore-forming potential (i.e., ore fertility). These components are not only key to the complexation and transport of ore metals during hydrothermal activity, but also influence the amount of ore metals transported by magmas and the efficiency to which they are transferred from magmas to exsolved fluids. Magmatic differentiation in lower crustal hot zones beneath thick crustal regions is expected to enhance the volatile element budget and oxygen fugacity of evolving magmas that are discharged to the upper crust. This occurs due to the accumulation of incompatible volatile elements during successive cycles of recharge by mafic magmas and crystallization, facilitated by the deeper and hotter conditions beneath thicker arc crusts. As such, an increasingly recognized hypothesis holds that ore-forming magmas display a particularly increased budget of volatile elements and higher oxygen fugacities when compared to barren arc magmas, and that this is largely influenced by the arc crust thickness. The proposed work will test this hypothesis by focusing on the Miocene to Mio-Pliocene magmatism and associated world-class PCD mineralization in the Andes of central Chile. From the Early Miocene to the Mio-Pliocene, the arc segment located between latitudes ~33–34.5° S in the Andes of central Chile has seen a continued increase in crustal thickness and has evolved from being barren in the Early Miocene to producing some of the largest PCDs of the world in the Mio-Pliocene, such as El Teniente and Rio Blanco-Los Bronces. This geological scenario and the spatial and age distribution of the associated outcropping intrusive rocks offer a unique opportunity to investigate the temporal evolution of the volatile composition of magmas and its consequences for ore fertility. The goal of this proposal is to examine, adopting a regional scale perspective, the evolution in the volatile composition and oxygen fugacity of magmas produced in this arc segment and its relationship to magmatic ore fertility, as well as how this may have been influenced by changes in crustal thickness. To achieve this, I will sample an extensive suite of granitoids that represent a continuum from Early Miocene to Mio-Pliocene magmas, including porphyry-forming intrusions. By combining zircon petrochronology, apatite, biotite, and amphibole mineral chemistry, in conjunction with the bulk-rock composition of intermediate to felsic intrusive rocks, I will be able to constrain relative changes in the hydration state, sulfur contents, halogen and oxygen fugacities, as well as in their associated crustal thickness during the evolution of the selected arc segment. This will be done by implementing a combination of cutting-edge analytical techniques, including synchrotron-based sulfur X-ray absorption near edge structure spectroscopy, electron probe microanalysis, (laser ablation) inductively coupled plasma mass spectrometry, and X-ray fluorescence spectrometry. I aim at (1) testing the differences in the volatile composition of barren and ore-forming intrusive rocks; (2) determining whether there is a gradual change in the volatile systematics of magmas during the evolution of the studied arc segment; and (3) analyzing the relationship between variations in crustal thickness and the volatile composition of associated magmas. The results of this proposal will lead to a better understanding of the magmatic controls underpinning the formation of giant PCDs and will provide valuable insights into identifying the differences between the bulk-rock and mineral chemistry of ore-forming and barren granitoids as tools for vectoring mineralized regions.