3 research outputs found
River Water Quality Analysis via Headspace Detection of Volatile Organic Compounds
No full textHuman civilization has intensified the interaction between the community and the environment. This increases the threat on the environm ent for being over exploited and contaminated with m anmade products and synthetic chemicals. Of all, clean water is one of the resources that can be easily contaminated since it is a universal solvent and of high mobility. This work reports the development and optimization of a water quality monitoring system based on metal oxide sensors. The system is intended to a ssist the detection of volatile organic compounds (VOCs) present in water sources online and onsite. The sampling mechanism was based on contactless mode, where headspace partial pressure of the VOCs formed above the water body in a close chamber was drawn for detection at the sensor platform. Pure toluene was used as standard to represent the broad spectrum of VOCs, and the sensor dynamic range was achieved from 1-1000 ppb. Several sensing parameters such as sampling time, headspace volume, and sensor recovery were s tudied and optimized. Besides direct detection of VOC contaminants in the water, the work has also been extended to detect VOCs produced by microbial communities and to c orrelate the size of the communities with the reading of V OCs recorded. This can serve to give b etter indication of water quality, not only on the conce ntration of VOCs c ontamination from chemicals, but also the content of microbes, which some can have severe effect on human health
Caracterización de los desórdenes de la conciencia
No full textilustraciones, gráficas, tablasDespués de una lesión cerebral severa algunos pacientes pueden presentar alteraciones graves de la conciencia. Estas lesiones limitan grandemente la calidad de vida de estos pacientes y en consecuencia la de su familia. Las ultimas dos décadas han suscitado especial interés el entendimiento, descripción y caracterización de forma objetiva de la dinámica cerebral en este grupo de pacientes. La consecuencia inmediata de este entendimiento es la construcción de herramientas que permitan mejorar la toma de decisiones para los médicos que asisten o intervienen a estos pacientes. Múltiples estrategias han sido exploradas para ello, desde la construcción de rigurosas pruebas comportamentales hasta el uso de novedosas técnicas de neuroimágenes. Estas ultimas han mostrado un futuro prometedor para el contexto de estudio, alcanzando transcendentales hallazgos en relación al entendimiento de la emergencia de la conciencia, su alteración en estados comatosos y hasta han derivado en potenciales herramientas diagnosticas. Sin embargo y muy a pesar de estos importantes logros, aún existen múltiples retos por resolver en él área. Uno de esos retos fundamentales es la definición de un marco experimental adecuado para modelar la dinámica cerebral dada su abrumadora complejidad. Diversas estrategias han sido propuestas, sin embargo, aún permanece la imposibilidad de unificar en una única representación los agentes más relevantes para la emergencia de la conciencia. Es así como, en esta tesis doctoral se explora una aproximación en la representación de la dinámica cerebral que generaliza la noción de conectividad funcional entre unidades cerebrales. Los resultados aquí descritos se discuten en el marco de la caracterización de la dinámica cerebral de pacientes con desordenes de la conciencia, y su potencial uso como biomarcadores se resaltan en los resultados de esta tesis doctoral. (texto tomado de la fuente)After a brain injury some patients may have severe disturbances in consciousness. These
injuries greatly limit the quality of life of these patients and their families. The last two
decades have raised special interest in the understanding, description and objective charac terization of brain dynamics in this group of patients. The immediate consequence of this
understanding is the construction of tools that allow better decision-making for the phy sicians who assist or intervene these patients. Multiple strategies have been explored for
this, from the construction of rigorous behavioral tests to the use of novel neuroimaging
techniques. Neuroimaging approach have shown a promising future in this context, reaching
transcendental findings in relation to the understanding of the emergence of consciousness,
its alteration in comatose states and have even led to potential diagnostic tools. However,
there are still many important challenges to overcome. One of these fundamental challenges
is the definition of a suitable experimental framework to model brain dynamics, because
the overwhelming complexity of this phenomena. Various strategies have been proposed, ho wever, the impossibility of unifying in a single representation the most relevant agents for
the emergence of consciousness still remains as an open problem. Thus, this doctoral thesis
explores an approach in the representation of brain dynamics that generalizes the notion of
functional connectivity between brain units. The results described here are discussed within
the framework of the characterization of the brain dynamics of patients with disorders of
consciousness, and their potential use as biomarkers is highlighted in the results of this doc toral thesis.DoctoradoDoctor en BiotecnologíaBioinformátic
