418 research outputs found
Reestructuración y crisis económica: un estudio sobre las nuevas formas de vida y trabajo en un grupo de familias de los sectores medios en la Ciudad de México
Interaction of Refractory Dibenzothiophenes and Polymerizable Structures
We carried out first principles calculations to show that polymerizable structures containing hydroxyl (alcoholic chain) and amino groups are suitable to form stable complexes with dibenzothiophene (DBT) and its alkyl derivates. These sulfur pollutants are very difficult to eliminate through traditional catalytic processes. Spontaneous and exothermic interactions at 0 K primarily occur through the formation of stable complexes of organosulfur molecules with monomeric structures by hydrogen bonds. The bonds are formed between the sulfur atom and the hydrogen of the hydroxyl group; additional hydrogen bonds are formed between the hydrogen atoms of the organosulfur molecule and the nitrogen atoms of the monomers. We vary the number of methylene groups in the alcoholic chain containing the hydroxyl group of the monomer and find that the monomeric structure with four methylene groups has the best selectivity towards the interaction with the methyl derivates with reference to the interaction with DBT. Even this study does not consider solvent and competitive adsorption effects; our results show that monomeric structures containing amino and hydroxyl groups can be used to develop adsorbents to eliminate organosulfur pollutants from oil and its derivates
Satisfacción marital y estado civil como factores protectores de la depresión y ansiedad
Esta investigación trata de determinar si el estado civil, el género y la satisfacción marital inciden como factores protectores en la depresión y la ansiedad en una muestra mexicana de 300 personas. Los resultados mostraron que los participantes separados presentaban mayores niveles de ansiedad y depresión que los casados. A su vez, la satisfacción marital fue un factor protector de los niveles de depresión en ambos géneros, obteniendo un mayor valor predictivo en las mujeres. También se evidenció que las mujeres con baja satisfacción marital presentaron mayores niveles de ansiedad que las mujeres con alta satisfacción marital. Estos resultados tienen implicaciones clínicas para paliar las posibles consecuencias tras una ruptura de pareja como son los trastornos ansioso o depresivo
Patent foramen ovale, deep venous thrombosis and stroke; a paradoxical embolism in an 80-year-old male
Background: A patent foramen ovale (PFO) is a congenital cardiac malformation describing a shunt in between the atrial walls. The overall incidence of a PFO is around 27.3% with a progressive decrease to 25.4% in the 4th and 8th decades. Once it has been established that a patient with an ischemic stroke/transient ischemic attack (TIA) has a PFO and other sources of the stroke have been ruled out, it is imperative to consider deep vein thrombosis (DVT) as the source of a paradoxical embolus. Case Presentation: 80-year-old gentleman with a history of right internal carotid occlusion of 80-90% status post right internal carotid endarterectomy. Presented to the emergency department (ED) for sudden left-sided weakness, left facial droop, slurred speech, and dizziness. Upon initial evaluation he was asymptomatic; NIH stroke score 1. Magnetic resonance imaging of the brain showed important watershed infarcts. Cerebral angiogram found 50% concentric stenosis of the right middle cerebral artery (MCA) with minimal lineal filling defect in the stenotic segment. The filling defect cleared after injection of intra-arterial integrillin. Post procedure, patient was started on heparin drip. Cardiology was consulted for suspected paroxysmal atrial fibrillation and a transesophageal echocardiogram (TEE). Two days after the post cerebral angiogram, the patient began to complain of severe right leg pain. He was noted to be tachycardic and hypoxemic. The venous doppler of the leg revealed a DVT and subsequent CT chest angiography revealed bilateral pulmonary embolism (PE). TEE results showed a positive agitative saline test with defect in the intra-atrial wall. The patient was on heparin drip and transitioned after 7 days to oral anticoagulation. Loop recorder was installed with possible PFO correction by cardiology in the outpatient. Patients\u27 symptoms improved and he was discharged to inpatient rehab. Conclusion: Although rare a paradoxical embolus should be considered in patients presenting with a stroke/TIA, PFO, and an unidentified source of embolus. Although this patient did have 50% occlusion of the R MCA, we cannot fully exclude a PFO-related stroke. The discovery of a DVT, and bilateral PEs supports the high suspicion for PFO-related stroke in the form of paradoxical embolus
El caso fortuito en la legislacion chilena: implicancias practicas y su necesidad de reforma a la luz del derecho comparado
50 p.Es en sucesos como el terremoto de 27 de febrero de 2010 ocurrido en Chile y sus consecuencias jurídicas, que cobra particular relevancia analizar el sistema de responsabilidad civil chileno en relación con el cumplimiento de las obligaciones, y particularmente, la figura del caso fortuito o fuerza mayor, ya que, de su ocurrencia derivará una importante consecuencia jurídica, como es la liberación de
responsabilidad del deudor respecto de la obligación contraída. Es así, que la presente investigación abordará los aspectos fundamentales
en torno a la figura del caso fortuito o fuerza mayor, principalmente sus requisitos, junto con lo señalado a su respecto por parte de la doctrina y jurisprudencia nacional, además de lo precisado por la doctrina extranjera en torno a ella, con el propósito de formular, finalmente, algunas impresiones tendientes a entender
cabalmente cómo opera dicha institución y su posible necesidad de reforma a la luz de lo planteado./ ABSTRACT: Incidents like the earthquake occurred in February 27th, 2010 in Chile and its legal consequences creates a special importance in the analysis of the Chilean
system of civil responsibility in relation with the obligations compliance, and particularly the fortuitous case or mayor strength, because if occur any of this legal types, it will take place an important legal consequence as the debtor release regarding the contracted obligation.
And so, this investigation will take the fundamental aspects around the fortuitous case figure or mayor strength, mainly the requirements, what it is said by the jurisprudence, the national and foreign doctrine, all this with the final purpose of generate some statements for understanding of this institution, and the possible reform of it
Situacion juridica de los animales a la luz de las presunciones de responsabilidad por el hecho de las cosas
50 p.La siguiente tesis no es autorizada por el autor para su difusion en formato digital.El análisis de la responsabilidad por el hecho de los animales es un tema que no deja escéptico a cualquiera, sobre todo con las diversas situaciones que han ocurrido en la actualidad como los ataques de perros considerados como peligrosos no han dejado indiferente a las autoridades. Pues bien, la presenteMemoria tiene por objeto determinar la situación jurídica de los animales y la responsabilidad por los hechos de los animales, junto con incorporar aspectos generales sobre el tratamiento que hace el derecho comparado sobre el tema, las críticas al actual sistema y su fundamentación teórica
Guidelines for a correct evaluation of deep eutectic solvents thermal stability
Deep eutectic solvents (DESs) are a class of versatile and green emerging materials. Despite the huge amounts of applications proposed in the last years, studies on their thermal stability are often missing. In this short review, we propose a guide for a correct evaluation of DES thermal stability, conducted mainly by dynamical thermogravimetry (TGA). We collected all the data reported in the literature on choline chloride (ChCl)-based DESs, as proof of concept to show the potentialities of the technique, highlighting all the parameters that need to be considered for a correct analysis, with particular attention to the possible sources of misleading interpretations (e.g. the adsorbed water, or the formation of undesired products during DES preparation). In many cases, the additional use of isothermal TGA, or TGA coupled with online techniques such as Fourier Infra-Red Spectroscopy or Mass Spectrometry, may help for the data interpretation. Besides, we summarize in a graph the degradation temperatures of many DESs and their precursors, intended as an operative guide to choosing the correct DES for different applications. The findings reported to date, highlight the potentialities of thermal analysis on DESs, as a powerful tool to obtain essential information on their applicability, and to implement the knowledge of their nanostructure from a molecular point of view
Análisis factorial confirmatorio del Cuestionario SA-45 en una muestra mexicana
El objetivo de la presente investigación consistió en examinar la estructura factorial, la fiabilidad y los datos normativos del Cuestionario SA-45 (Symptom Assessment-45) en una muestra de estudiantes universi-tarios mexicanos. Como se predijo, los análisis factoriales confirmatorios indicaron que el modelo de nueve factores proporcionaba el mejor ajuste del SA-45. Así mismo, los datos demostraron buenos niveles de fiabilidad (consistencia interna) del cuestionario. Los datos normativos mostraron que las mujeres puntuaban más alto que los varones en todas las escalas excepto en psicoticismo. En general, el estudio proporciona apoyo trans-cultural consistente sobre la fiabilidad y validez del cuestionario
Detailed characterization of the solution kinetics and thermodynamics of biotin, biocytin and HABA binding to avidin and streptavidin
The high affinity (KD ~ 10−15 M) of biotin for avidin and streptavidin is the essential component in a multitude of bioassays with many experiments using biotin modifications to invoke coupling. Equilibration times suggested for these assays assume that the association rate constant (kon) is approximately diffusion limited (109 M-1s-1) but recent single molecule and surface binding studies indicate that they are slower than expected (105 to 107 M-1s-1). In this study, we asked whether these reactions in solution are diffusion controlled, which reaction model and thermodynamic cycle describes the complex formation, and if there are any functional differences between avidin and streptavidin. We have studied the biotin association by two stopped-flow methodologies using labeled and unlabeled probes: I) fluorescent probes attached to biotin and biocytin; and II) unlabeled biotin and HABA, 2-(4’-hydroxyazobenzene)- benzoic acid. Both native avidin and streptavidin are homo-tetrameric and the association data show no cooperativity between the binding sites. The kon values of streptavidin are faster than avidin but slower than expected for a diffusion limited reaction in both complexes. Moreover, the Arrhenius plots of the kon values revealed strong temperature dependence with large activation energies (6–15 kcal/mol) that do not correspond to a diffusion limited process (3–4 kcal/mol). Accordingly, we propose a simple reaction model with a single transition state for non-immobilized reactants whose forward thermodynamic parameters complete the thermodynamic cycle, in agreement with previously reported studies. Our new understanding and description of the kinetics, thermodynamics, and spectroscopic parameters for these complexes will help to improve purification efficiencies, molecule detection, and drug screening assays or find new applications
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