2,211 research outputs found

    Generalized Fick Jacobs Approach for describing Adsorption Desorption Kinetics in Irregular Pores under Non Equilibrium Conditions

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    We present a study exploring the range of applicability of a generalized Fick Jacobs equation in the case when diffusive mass transport of a fluid along a pore includes chemical reactions in the bulk and pore surface. The study contemplates nonequilibrium boundary conditions and makes emphasis on the comparison between the predictions coming from the projected Fick Jacobs description and the corresponding predictions of the original two dimensional mass balance equation, establishing a simple cuantitative criterion of validity of the projected description. For the adsorption desorption process, we demonstrate that the length and the local curvature of the pore are the relevant geometric quantities for its description, allowing for giving very precise predictions of the mass concentration along the pore. Some schematic cases involving adsorption and chemical reaction are used to quantify with detail the concentration profiles in transient and stationary states involving equilibrium and nonequilibrium situations. Our approach provides novel and important insights in the study of diffusion and adsorption in confined geometries.Comment: 19 pages, 8 figure

    El servicio comunitario, una experiencia de innovación educativa en Venezuela

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    ResumenEl servicio comunitario del estudiante de educación superior se estableció por decisión de la asamblea nacional de la república bolivariana de Venezuela en el año 2005, con la intención de integrar a la universidad con los miembros de la comunidad, mediante la participación activa y protagónica del sector estudiantil y del sector profesoral en la búsqueda de soluciones a los problemas nacionales, a través del diseño y ejecución de proyectos sociales. Utiliza el aprendizaje-servicio como una metodología que promueve el desarrollo de competencias a través de actividades educativas de servicio a la comunidad, basándose en la convicción de que puede ser un factor de transformación de la realidad social. El contenido de la conferencia se referirá a las bases legales del servicio, a los aspectos metodológicos implementados a través de cursos de los inducción y al impacto social, político y económico de la ejecución de algunos proyectos en la realidad nacional venezolana.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Péptidos antihipertensivos derivados de proteínas lácteas

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    La leche es una excelente fuente de nutrientes. Mas allá de su bien documentada función nutricional, la leche ejerce un amplio rango de actividades biológicas que influyen sobre el sistema digestivo y metabólico, el crecimiento y desarrollo de los órganos y la resistencia a diversos trastornos y enfermedades. Estas actividades han sido atribuidas principalmente a las proteínas y péptidos secretados en la leche por la glándula mamaria. Sin embargo, algunas de las actividades biológicas de las proteínas lácteas se encuentran en un estado latente y requieren de procesos de proteolisis para su liberación.Este trabajo ha sido realizado en el marco del Proyecto CYTED XI.24. También se agradece a los Proyectos Consolider 2010 CS-063 y CM-S0505 -AGR-0153 y AGL- 2007 065035. Blanca Hernández-Ledesma disfruta de un contrato post-doctoral Marie-Curie de la Comisión Europea coordinado por el Consejo Superior de Investigaciones Científicas. María del Mar Contreras disfruta de una beca DANONE.Peer Reviewe

    Mudanças no perfil funcional de pacientes con patologia psiquiátrica resistente submetidos a neurocirurgia funcional estereotáxica

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    Con el objetivo de evaluar los resultados de la Neurocirugía Funcional Estereotáctica (NFE) sobre el perfil funcional de los pacientes diagnosticados con Patología Psiquiátrica Resistente (PPR), se realizó un diseño pre/post tratamiento. 13 pacientes fueron evaluados ( = 31 ± 8 años): siete mujeres diagnosticadas con algún Trastorno de la Conducta Alimentaria Resistente (TCAR); tres mujeres diagnosticadas con Trastornos Resistentes Obsesivo Compulsivo y Depresivo (TOC y DR) y tres pacientes (dos mujeres y un hombre) diagnosticados con Depresión Resistente (DR). A estos pacientes se les aplicó la Escala de funcionamiento del paciente Eje K, la cual consta de siete subescalas, y una Escala de Evaluación de la Actividad Global (EAG) antes del tratamiento y después de éste (seis meses posteriores a la NFE). Todos los grupos diagnósticos y el total de los pacientes evaluados presentaron cambios clínicos positivos; sin embargo, sólo el grupo de TCAR mostró importantes cambios clínicos de mejoría en el perfil de funcionamiento, siendo esta diferencia estadísticamente significativa (pre Md = 56; post Md = 84; z= - 2.36, p <0.05). Con la evidencia obtenida se observó que la NFE representa una opción terapéutica emergente efectiva orientada a disminuir el sufrimiento de los pacientes con PPR, así como a mejorar el nivel de funcionamiento global y por ende su calidad de vida. Todos los pacientes del estudio presentaban una condición de resistencia a tratamientos convencionales indicados, la cual había sido documentada por un equipo interdisciplinario experto.Con o objetivo de avaliar os resultados da Neurocirurgía Funcional Estereotáxica (NFE) sobre o perfil funcional dos pacientes diagnosticados com Patologia Psiquiátrica Resistente (PPR), realizou-se um desenho pré/pós tratamento. 13 pacientes foram avaliados ( = 31 ± 8 anos): sete mulheres diagnosticadas com algum Transtorno da Conduta Alimentar Resistente (TCAR); três mulheres diagnosticadas com Transtornos Resistentes Obsessivo Compulsivo e Depressivo (TOC e DR) e três pacientes (duas mulheres e um homem) diagnosticados com Depressão Resistente (DR). A estes pacientes foi aplicada a Escala de funcionamento do paciente Eixo K, a qual consta de sete sub-escalas, e uma Escala de Avaliação da Atividade Global (EAG) antes do tratamento e depois dele (seis meses posteriores à NFE). Todos os grupos diagnósticos e o total dos pacientes avaliados apresentaram mudanças clínicas positivas; porém, só o grupo de TCAR mostrou importantes mudanças clínicas de melhoria no perfil de funcionamento, sendo esta diferença estatisticamente significativa (pré Md= 56; pós Md= 84; z= - 2.36, p <0.05). Com a evidência obtida observou-se que a NFE representa uma opção terapêutica emergente efetiva orientada a diminuir o sofrimento dos pacientes com PPR, bem como a melhorar o nível de funcionamento global e portanto sua qualidade de vida. Todos os pacientes do estudo apresentavam uma condição de resistência a tratamentos convencionais indicados, a qual havia sido documentada por uma equipe interdisciplinar de especialistas.In order to evaluate the results of the Stereotactic Functional Neurosurgery (SFN) on the functional profile of patients diagnosed with Resistant Psychiatric Pathology (RPP), a pre / post treatment design was performed. Thirteen patients were assessed ( = 31 ± 8 years): seven women diagnosed with some type of Resistant Eating Disorder (RED); three women diagnosed with Resistant Obsessive Compulsive Disorder and Resistant Depression (TOC and RD), and three patients (two women and one man) diagnosed with Resistant Depression (RD). The Patient's Functioning Scale, axis K, consisting of seven subscales, and the Assessment of Global Activity Scale (AGAS) were applied before and after treatment (6 months after FSN). All diagnostic groups and all the patients assessed showed positive clinical changes. However, only the RED group showed important clinical improvement in the performance profile with a statistically significant difference (pre Md = 56, Md = 84 post , z = - 2.36, p <0.05). With the evidence obtained it was noted that SFN represents an effective therapeutic option aimed at reducing the suffering of patients with RPP and improve their overall level of functioning and therefore their quality of life. All patients in the study had a condition indicating resistance to conventional treatments which had been documented by an expert multidisciplinary team

    Study on frequency of dental developmental alterations in a MEXICAN school-based population

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    Background: The aim of this study was to know the distribution of dental developmental alterations in the population requesting stomatological attention at the Admission and Diagnosis Clinic of our institution in Mexico City. Material and Methods: We reviewed the archives and selected those files with developmental dental alterations. Analyzed data were diagnoses, age, gender, location and number of involved teeth. Results: Of the 3.522 patients reviewed, 179 (5.1%) harbored 394 developmental dental alterations. Of them, 45.2% were males and 54.8% were females with a mean age of 16.7 years. The most common were supernumeraries, dental agenesia and dilaceration. Adults were 30.7% of the patients with dental developmental alterations. In them, the most common lesions were agenesia and supernumeraries. Mesiodens was the most frequently found supernumerary teeth (14.7%). Conclusions: Our finding that 30.7% of the affected patients were adults is an undescribed and unusually high proportion of patients that have implications on planning and prognosis of their stomatological treatment

    Frecuencia de dientes supernumerarios en una población mexicana

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    Los dientes supernumerarios (DS) son una anomalía del desarrollo que no se observa con frecuencia (del 0.3 al 3.8% de la población). En este estudio, se analizaron las ortopantomografías correspondientes a 2241 pacientes, de ambos sexos quienes acudieron a la Clínica de Admisión de la División de Estudios de Posgrado e Investigación, Facultad de Odontología, UNAM en la ciudad de México D.F. De ellos, se encontraron 72 pacientes (3.2%) con 102 DS. De los 72 pacientes, 39 fueron hombres (54.2%) y 33 mujeres (45.8%). El mesiodens fue el más común de los DS (48.6%), seguido por lo premolares supernumerarios (26.4%), laterales supernumerarios (11.1%) y cuartos molares (9.7%). En esta serie se incluyen casos con uno, dos, tres DS y un caso con 10 DS. Nuestros resultados sugieren que la frecuencia de DS en la población estudiada es diferente en algunos aspectos a la que se reporta en otras series. Como demuestran nuestros resultados, se aconseja que se tomen radiografías panorámicas a todos los pacientes que se atiendan en los consultorios dentales, clínicas y facultades ó escuelas de Odontología, para poder detectar procesos patológicos ocultos.Supernumerary teeth (ST) are a not uncommon developmental anomaly which appears in 0.3 to 3.8 percent of the population. We studied the corresponding radiographs from 2241 patients, both sexes who seeked dental attention at the Outpatient Clinic of the División de Estudios de Posgrado e Investigación, Facultad de Odontología, UNAM in Mexico City. Of them, we found 72 patients (3.2%) with 102 ST. Of the 72 patients, 39 were males (54.2%) and 33 females (45.8%). Mesiodens was the most common ST (48.6%), followed by supernumerary premolars (26.4%), supernumerary laterals (11.1%) and fourth molars (9.7%). This series includes cases with one, two and three ST and one case comprising 10 ST. Our results suggest that frequency of ST in the population studied differs in some aspects with previously reported series and that frequency of ST shows different rates depending the population studied. As our results demonstrate, it is encouraged the need to have panoramic radiographs of all patients attended in dental offices, clinics and schools of Dentistry in order to detect and diagnose undiscovered pathologies

    Influence of protein-phenolic complex on the antioxidant capacity of flaxseed (Linum usitatissimum L.) products

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    The impact of the naturally present phenolic compounds and/or proteins on the antioxidant capacity of flaxseed products (phenolic fraction, protein concentrates, and hydrolysates) before and after simulated gastrointestinal digestion was studied. For that, whole and phenolic reduced products were assessed. Four glycosylated phenolic compounds (secoisolariciresinol and ferulic, p-coumaric, and caffeic acids) were identified in flaxseed products. Phenolic fraction exerts the highest antioxidant capacity that increased by alkaline hydrolysis and by simulated gastrointestinal digestion. The action of Alcalase and digestive enzymes resulted in an increase of the antioxidant capacity of whole and phenolic reduced products. Principal component analysis showed that proteinaceous samples act as antioxidant is by H transfer, while those samples containing phenolic compounds exert their effects by both electron donation and H transfer mechanisms. Protein/peptide-phenolic complexation, confirmed by fluorescence spectra, exerted a positive effect on the antioxidant capacity, mainly in protein concentrates.This work was supported by FAPESP (2010/52680-7), CNPq and UNICAMP (FAEPEX 607-11) grants, CSIC and Ministry of Economy and Competitiveness (Ramon y Cajal contract).Peer Reviewe
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