Simulaciones de sistemas acuosos: de la fase gas a la fase condensada

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Química. Fecha de lectura: 21-11-2017La presente tesis está dedicada a la simulación de sistemas acuosos desde la fase gas hasta la fase condensada. En la misma, se utilizaron enfoques y métodos complementarios para estudiar sistemas acuosos homogéneos y heterogéneos. En particular, se ofrece un análisis detallado de las propiedades estructurales, termodinámicas, espectroscópicas y de transporte en distintas condiciones termodinámicas para estos sistemas. A lo largo de todo el trabajo, las comparaciones entre el experimento y la teoría se establecieron sobre la base de la naturaleza de la interacción entre diferentes sistemas: Agua-Agua, Ion-Agua y hospedador-huésped (agua). Así, el presente trabajo se ha dividido en tres partes principales. En la primera parte, se realizaron simulaciones de dinámica molecular clásica en función de la temperatura para estudiar y determinar las propiedades estructurales y de transporte (tanto individuales como colectivas) del agua líquida. Hasta la fecha, la estimación de viscosidades a partir de simulaciones representa un problema computacional desafiante ya que se requieren tiempos de simulación largos para alcanzar precisión estadística, por lo que aquí se compararon varias estrategias de simulación y también se validan diversos potenciales de interacción disponibles en la literatura. En la segunda parte, se utilizaron cálculos de estructura electrónica de última generación para diseñar, desde un enfoque bottom-up, superficies de energías de potencial analíticas de alta precisión. Dichos modelos de interacción transferibles, son los primeros potenciales de ion-agua polarizables completamente ab-initio para el estudio de electrolitos en diferentes entornos acuosos, por ejemplo, desde la microsolvatación de monohidratos a polihidratos, así como soluciones a dilución infinita, y propiedades interfaciales. En una colaboración con dos grupos experimentales (EEUU y UE), predecimos y validamos la dependencia de la temperatura en el mecanismo de predisociación de un ion en contacto con dos moléculas de agua mediante simulaciones de dinámica molecular mixtas clásico-cuánticas. Finalmente en la tercera parte, estudiamos la encapsulación de átomos y moléculas dentro de las cavidades del clatrato hidrato sI. Estas investigaciones estuvieron motivadas por la disponibilidad de mediciones experimentales a partir de difracción de rayos X y espectros IR, así como de transiciones de fase observadas en el bulk. Para ello, se tomaron como sistemas de referencia el hidrato clatrato de dióxido de carbono, y los hidrato clatrato de gases nobles. En particular se llevaron a cabo cálculos cuánticos con el método de “Multiconfigurational Time Dependent Hartree” para las dos cavidades de clatrato CO2@sI, y por primera vez se presentan resultados sobre los estados traslacionales-rotacionales-vibracionales de dicho sistema. Además, se comprobó el rendimiento de diferentes modelos de interacción analítica, así como cálculos de estructura electrónica para describir la orientación rotacional y la anisotropía angular dentro de ambas cavidades. De igual manera, se llevaron a cabo simulaciones clásicas de “parallel-tempering Monte Carlo” en el ensamble isobárico-isotérmico (NPT) para agregados tipo clatratos con gases nobles de tamaño seleccionado y se presentó un análisis detallado de sus diagramas de fase en temperatura y presión, así como cambios estructurales en un amplio rango de presiones y temperatura.The present thesis is devoted to the simulations of aqueous systems from the gas to the condensed phase. Here we used complementary approaches and methods to study both homogeneous and heterogeneous aqueous systems. In particular, we provided a detailed analysis on their, structural, thermodynamical, spectroscopical and transport properties at different thermodynamic conditions. Along the whole work, comparisons between experiment and theory were established based on the nature of the interactions between different systems. It was divided into three main parts corresponding to: water-water, ion-water and guest-host(water network). In the first part, classical molecular dynamic simulations were performed as a function of temperature, to study and determine the structural and transport properties (both single and collective) of liquid water. Nowadays, the estimation of viscosities from simulations is a challenging computational problem, as long simulation times are required to reach statistical accuracy. So several simulation strategies were compared being able to validate interaction model potentials available in the literature. In the second part, state-of-the-art electronic structure calculations were employed to design, from a bottom-up approach, highly accurate analytical potential energy surfaces. Such transferable interaction models are the first fully ab-initio polarizable ion-water potentials for studying electrolytes at different aqueous environments i.e. from the microsolvation of monohydrates, to polyhydrates, as well as solutions at infinite dilution, and interfacial properties. In a collaboration with two experimental groups (USA and EU) we predict and validate the temperature dependence vibrational predissociation mechanism of an ion in contact with two water molecules by means of mixed quantum-classical molecular dynamic simulations. Finally in the third part, we studied the encapsulation of atoms and molecules within the cavities of sI type clathrate hydrates. These investigations were motivated by available experimental measurements from X-ray diffraction and IR spectra, as well as observed phase transitions in the bulk. For such, we took as reference systems the carbon dioxide clathrate hydrate and the rare gases (Rg) clathrate hydrates. In particular, we performed quantum multi-configuration time-dependent Hartree calculations for the two cages of the sI CO2 clathrate hydrate, and we reported for the first time results on the translational, rotational and vibrational states. Additionally, we tested the performance of different analytical interaction models, as well as electronic structure calculations for describing the rotational orientations and angular anisotropy of the CO2 within both cages. Moreover, classical parallel-tempering Monte Carlo simulations in the isobaric-isothermic (NPT) ensemble were carried out for size-selected Rg clathrate-like clusters and we presented a detailed analysis of their temperature-pressure phase diagrams, as well as structural changes in a wide range of temperatures and pressuresEste trabajo de investigación ha sido posible gracias a la concesión de una beca predoctoral BES2012-054209 enmarcada en el subprograma de ayudas de formación de personal investigador (FPI) del gobierno español, a través del Ministerio de Economía, Industria y Competitividad, y asociada al proyecto de investigación FIS2014-51933-P del CSIC

Importance and repercussions of renal and cardiovascular pathology on stroke in young adults: an anatomopathologic study of 52 clinical necropsies

INTRODUCTION: Stroke in young adults has seldom been studied in a necropsy series. The objective of the present clinical necropsy-based investigation was to analyze stroke and its relationship with cardiovascular and renal pathology in young adults. MATERIALS AND METHODS:The protocols of 52 clinical necropsies with diagnoses of stroke in patients aged 18 - 49 years, performed between the years 1990-2006, were reviewed. RESULTS: Hemorrhagic stroke was diagnosed in 36 patients (69.3%), whereas the remaining 16 (30.7%) had ischemic stroke. Hypertensive cardiopathy was evident in 88.4% of the cases. Chronic renal pathology, directly or indirectly related to hypertension, was observed in 55.7% of the patients. Ischemic stroke as a result of occlusive atherosclerotic disease was seen in 50% of cases. Cardiogenic emboli were found in 25% of the cadavers. Hemorrhagic stroke was associated with hypertension in 43% of the cases, with ruptured vascular malformations in 29%, and coagulopathies in 17% of the cases. Hypertensive cardiopathy was present in patients with either ischemic or hemorrhagic stroke (81.2% and 91.6%, respectively). The most frequently observed renal ailments were chronic pyelonephritis (23%) and nephrosclerosis (21.1%). These were associated with ischemic stroke in 43.7%, and 12.5% of the cases, respectively, and with 13.8% and 25% of the hemorrhagic stroke cases. DISCUSSION: Hypertensive cardiopathy, occlusive atherosclerotic disease, chronic pyelonephritis and nephrosclerosis are among the pathophysiologycal mechanisms that apparently and eventually interact to induce a significant number of cases of stroke in young adults. A chronic systemic inflammatory state appears to be an important related condition because it possibly constitutes an accelerant of the pathophysiologycal process

Importance and repercussions of renal and cardiovascular pathology on stroke in young adults: an anatomopathologic study of 52 clinical necropsies

INTRODUCTION: Stroke in young adults has seldom been studied in a necropsy series. The objective of the present clinical necropsy-based investigation was to analyze stroke and its relationship with cardiovascular and renal pathology in young adults. MATERIALS AND METHODS:The protocols of 52 clinical necropsies with diagnoses of stroke in patients aged 18 - 49 years, performed between the years 1990-2006, were reviewed. RESULTS: Hemorrhagic stroke was diagnosed in 36 patients (69.3%), whereas the remaining 16 (30.7%) had ischemic stroke. Hypertensive cardiopathy was evident in 88.4% of the cases. Chronic renal pathology, directly or indirectly related to hypertension, was observed in 55.7% of the patients. Ischemic stroke as a result of occlusive atherosclerotic disease was seen in 50% of cases. Cardiogenic emboli were found in 25% of the cadavers. Hemorrhagic stroke was associated with hypertension in 43% of the cases, with ruptured vascular malformations in 29%, and coagulopathies in 17% of the cases. Hypertensive cardiopathy was present in patients with either ischemic or hemorrhagic stroke (81.2% and 91.6%, respectively). The most frequently observed renal ailments were chronic pyelonephritis (23%) and nephrosclerosis (21.1%). These were associated with ischemic stroke in 43.7%, and 12.5% of the cases, respectively, and with 13.8% and 25% of the hemorrhagic stroke cases. DISCUSSION: Hypertensive cardiopathy, occlusive atherosclerotic disease, chronic pyelonephritis and nephrosclerosis are among the pathophysiologycal mechanisms that apparently and eventually interact to induce a significant number of cases of stroke in young adults. A chronic systemic inflammatory state appears to be an important related condition because it possibly constitutes an accelerant of the pathophysiologycal process

Seguros colaborativos en grupos de confianza

Incluye BibliografíaTreysta, “confianza” en nórdico antiguo, es una compañía que basa su propuesta de valor en generar una oportunidad de ahorro para las personas en la póliza de seguro de sus automóviles. La empresa se sitúa en la industria de la venta de seguros de automóviles en Uruguay, integrándose en la cadena de valor como intermediario entre los dueños de automóviles y las aseguradoras. Treysta tiene por objetivo recompensar a los buenos conductores, para lo cual propone generar una estructura compuesta por grupos a modo de círculos cerrados que los contienen y donde, además, existe un vínculo de confianza entre ellos. El propósito de esto es obtener un beneficio común, el cual se logra en forma de ahorro en la póliza de seguro del automóvil. Dentro de cada grupo, los usuarios pagan el mismo monto que antes -es decir, que contratando a su actual aseguradora-por su póliza, donde una parte se destina a la aseguradora y otra parte se vuelca en un “pozo común” o pool. En la eventualidad de un siniestro, parte de los costos del arreglo serán cubiertos por el pool y, dependiendo de la entidad del incidente, se podrá activar o no la póliza. Si al final del período no ocurrieron siniestros o dicha cantidad fue reducida dentro de su grupo, el usuario recupera parte del costo de la póliza. La propuesta de valor se centra fundamentalmente en tres puntos; creación de la oportunidad de ahorro de hasta un 30%, obtención de un mejor servicio a un precio similar y una atención individualizada, orientada a la calidad del servicio. Para lograr generar los beneficios anteriores, se negociará con las aseguradoras, pólizas de seguro bonificadas. Esto se logrará mediante la contratación de las mismas utilizando un deducible facultativo, así como también utilizando un mecanismo de “paquetización” de pólizas y cobrando una menor comisión por intermediación

The Systemic Inflammome of Severe Obesity before and after Bariatric Surgery

Obesity is associated with low-grade systemic inflammation. The "inflammome" is a network layout of the inflammatory pattern. The systemic inflammome of obesity has not been described as yet. We hypothesized that it can be significantly worsened by smoking and other comorbidities frequently associated with obesity, and ameliorated by bariatric surgery (BS). Besides, whether or not these changes are mirrored in the lungs is unknown, but obesity is often associated with pulmonary inflammation and bronchial hyperresponsiveness. We sought to: (1) describe the systemic inflammome of morbid obesity; (2) investigate the effects of sex, smoking, sleep apnea syndrome, metabolic syndrome and BS upon this systemic inflammome; and, (3) determine their interplay with pulmonary inflammation. We studied 129 morbidly obese patients (96 females; age 46±12 years; body mass index [BMI], 46±6 kg/m 2) before and one year after BS, and 20 healthy, never-smokers, (43±7 years), with normal BMI and spirometry. Before BS, compared with controls, all obese subjects displayed a strong and coordinated (inflammome) systemic inflammatory response (adiponectin, C-reactive protein, interleukin (IL)-8, IL-10, leptin, soluble tumor necrosis factor-receptor 1(sTNF-R1), and 8-isoprostane). This inflammome was not modified by sex, smoking, or coexistence of obstructive sleep apnea and/or metabolic syndrome. By contrast, it was significantly ameliorated, albeit not completely abolished, after BS. Finally, obese subjects had evidence of pulmonary inflammation (exhaled condensate) that also decreased after BS. The systemic inflammome of morbid obesity is independent of sex, smoking status and/or comorbidities, it is significantly reduced by BS and mirrored in the lungs

Relationships derived from relationships: Competition between arbitrary relationships and physical similarity

El estudio de las relaciones de similitud física (RSF) y las relaciones arbitrarias resulta de interés ya que permite evaluar la capacidad de formación y discriminación de nuevas relaciones entre estímulos cuando está disponible un criterio de respuesta potencialmente más arraigado, como el de similitud física. El propósito del presente estudio fue investigar los efectos de la competencia de respuesta entre las relaciones derivadas de relaciones (RDR) y las RSF. Se consideraron como indicadores de respuesta el número de respuestas por las RDR y los tiempos de respuesta. Participaron del estudio 158 sujetos adultos. Los resultados demostraron que, cuando los participantes formaron RDR consistentemente, la presencia de competencia no generó dificultad para seleccionar respuestas por RDR. Los participantes que respondieron inconsistentemente a las RDR, sí presentaron efectos de competencia en ambos indicadores de respuesta. Se pone de manifiesto la conveniencia de utilizar los tiempos de respuesta además de la cantidad de respuestas por la RDR, como una medida más fina del control de estímulos y de estudiar tanto el desempeño de los participantes que responden consistentemente a todas las relaciones derivadas como el de aquellos que sólo exhiben consistencia en el establecimiento de clases de equivalencia de estímulos. Debe atenderse tanto a las relaciones que son estrictamente arbitrarias, como también a las RSF en tanto se sabe que la tendencia a considerar estas relaciones estaría también en la base del formación del razonamiento analógico.The study of physical similarity relationships (PSR) and arbitrary relationships is of interest because it allows the assessment of the ability to form and discriminate new relationships between stimuli when another response criterion more established is potentially available, like that of physical similarity. The importance of this type of relational responding is that this behavior is similar to that of analogical reasoning and its study has the advantage of allowing systematic control of familiarity and stimulus learning. The relationships derived from relationships (RDR) imply the ability to establish relationships based not on the stimulus, but on the relations established between combinations of stimuli. In this sense, it is necessary to address both the relationships that are strictly arbitrary as well as PSR, as it is known that the tendency to consider these relationships would also be the basis for the formation of analogical reasoning. The purpose of this study was to investigate the effects of response competition between the RDR and the PSR. The number of responses by the RDR and response times were considered as indicators of response. The study included 158 adult subjects. The results showed that when participants formed RDR consistently, the presence of competition did not cause difficulties in selecting responses by RDR. By contrast, participants who responded inconsistently to the RDR did show effects of competition in both indicators of response. The advantage of using the response times in addition to the number of responses by the RDR is shown as a finer measure of stimulus control. In turn, a special emphasis is made on the importance of studying both the performance of the participants who responded consistently to all derived relations as well as those that only exhibit consistency in establishing stimulus equivalence classes.Fil: Fiorentini, Leticia. Universidad de Buenos Aires. Facultad de Psicología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Arismendi, Mariana. Universidad de Buenos Aires. Facultad de Psicología; ArgentinaFil: Vernis, Sergio. Universidad de Buenos Aires. Facultad de Psicología; ArgentinaFil: Primero, Gerardo. Universidad de Buenos Aires. Facultad de Psicología; ArgentinaFil: Sánchez, Federico José. Universidad de Buenos Aires. Facultad de Psicología; ArgentinaFil: Tabullo, Angel Javier. Universidad de Buenos Aires. Facultad de Psicología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Iorio, Alberto Andres. Universidad de Buenos Aires. Facultad de Psicología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentin

The systemic inflammome of severe obesity before and after bariatric surgery

INTRODUCTION: Obesity is associated with low-grade systemic inflammation. The 'inflammome' is a network layout of the inflammatory pattern. The systemic inflammome of obesity has not been described as yet. We hypothesized that it can be significantly worsened by smoking and other comorbidities frequently associated with obesity, and ameliorated by bariatric surgery (BS). Besides, whether or not these changes are mirrored in the lungs is unknown, but obesity is often associated with pulmonary inflammation and bronchial hyperresponsiveness. OBJECTIVES: We sought to: (1) describe the systemic inflammome of morbid obesity; (2) investigate the effects of sex, smoking, sleep apnea syndrome, metabolic syndrome and BS upon this systemic inflammome; and, (3) determine their interplay with pulmonary inflammation. METHODS: We studied 129 morbidly obese patients (96 females; age 46 ± 12 years; body mass index [BMI], 46 ± 6 kg/m2) before and one year after BS, and 20 healthy, never-smokers, (43 ± 7 years), with normal BMI and spirometry. RESULTS: Before BS, compared with controls, all obese subjects displayed a strong and coordinated (inflammome) systemic inflammatory response (adiponectin, C-reactive protein, interleukin (IL)-8, IL-10, leptin, soluble tumor necrosis factor-receptor 1(sTNF-R1), and 8-isoprostane). This inflammome was not modified by sex, smoking, or coexistence of obstructive sleep apnea and/or metabolic syndrome. By contrast, it was significantly ameliorated, albeit not completely abolished, after BS. Finally, obese subjects had evidence of pulmonary inflammation (exhaled condensate) that also decreased after BS. CONCLUSIONS: The systemic inflammome of morbid obesity is independent of sex, smoking status and/or comorbidities, it is significantly reduced by BS and mirrored in the lungs