RESUMO
In the present research work, the temperature effect on the corrosion inhibition process of API 5L X60 steel in 1 M H2SO4 by employing three vinylimidazolium poly(ionic liquid)s (PILs) was studied by means of electrochemical techniques, surface analysis and computational simulation. The results revealed that the maximal inhibition efficiency (75%) was achieved by Poly[VIMC4][Im] at 308 K and 175 ppm. The PILs showed Ecorr displacements with respect to the blank from -14 mV to -31 mV, which revealed the behavior of mixed-type corrosion inhibitors (CIs). The steel micrographs, in the presence and absence of PILs, showed less surface damage in the presence of PILs, thus confirming their inhibiting effect. The computational studies of the molecular orbitals and molecular electrostatic potential of the monomers suggested that the formation of a protecting film could be mainly due to the nitrogen and oxygen heteroatoms present in each structure.
Assuntos
Líquidos Iônicos , Temperatura , Aço/química , Corrosão , Carbono , ÁcidosRESUMO
Introducción: El delineador de señales electrocardiográficas (ECG) multiderivación basado en la transformada wavelet posee alta resolución espacial y permite eliminar las diferencias interderivación que aparecen tradicionalmente en los métodos uniderivación. Para esto necesita de derivaciones de señales electrocardiográficas ortogonales entre sí para la obtención de un bucle espacial. Objetivo: Desarrollar métodos de ortogonalización de dos o tres derivaciones de señales electrocardiográficas que permitan la generalización del delineador multiderivación basado en la transformada wavelet en cualquier base de datos señales electrocardiográficas con más de una derivación. Métodos: Se implementaron tres métodos de ortogonalización de derivaciones de señales electrocardiográficas: ortogonalización de dos derivaciones a partir de la proyección de vectores, ortogonalización a partir de componentes principales y ortogonalización a partir del método clásico de Gram-Schmidt. Resultados: Se comparó el funcionamiento del delineador multiderivación de ECG cuando es usado cada método de ortogonalización, mediante el cálculo de la media aritmética y la desviación estándar teniendo en cuenta diferentes combinaciones de derivaciones de ambas bases de datos para cada una de las marcas analizadas. Los mejores resultados se obtuvieron con el método análisis de componentes principales y el peor comportamiento con el método de ortogonalización de dos derivaciones. Conclusiones: Los algoritmos de ortogonalización que obtuvieron los mejores resultados fueron los basados en tres derivaciones ortogonales, en la que fue ligeramente superior la descomposición en componentes principales y, por tanto, se considera el método más adecuado para la generalización del delineador multiderivación(AU)
Introduction: The wavelet transform-based multiderivation electrocardiographic (ECG) signal delineator has high spatial resolution and makes it possible to eliminate interderivation differences traditionally appearing in uniderivation methods. But this requires electrocardiographic signal derivations orthogonal to one another to obtain a spatial loop. Objective: Develop orthogonalization methods of two or three electrographic signal derivations allowing generalization of the wavelet transform-based multiderivation delineator in any electrographic signal database with more than one derivation. Methods: Three orthogonalization methods were implemented for electrocardiographic signal derivations: vector projection-based two-derivation orthogonalization, principal component-based orthogonalization, and orthogonalization based on the Gram-Schmidt classic method. Results: A comparison was performed between the operation of the ECG multiderivation delineator when used with each orthogonalization method. The comparison was based on estimation of the arithmetic mean and standard deviation bearing in mind different combinations of derivations from both databases for each of the marks analyzed. The best results were obtained with the principal component analysis method and the worst ones with the two-derivation orthogonalization method. Conclusions: The orthogonalization algorithms obtaining the best results were those based on three orthogonal derivations, in which decomposition into principal components was slightly higher. This is therefore considered to be the most appropriate method for generalization of the multiderivation delineator(AU)
Assuntos
Humanos , Masculino , Feminino , Algoritmos , Análise de Componente Principal/métodos , Eletrocardiografia/métodos , Análise de OndaletasRESUMO
In this article, we call into question recent public health claims that loneliness is a problem of epidemic proportions. Current research on this topic is hindered by an overreliance on limited survey data and by paradigmatic imbalance that delineates the study of loneliness to psychological, cognitive, neuroendocrinological and immunological effects, social functioning, physical health, mortality, and gene effects. The article emphasizes that scientific approaches to the phenomena of loneliness are more appropriately conceived and investigated as inherently matters for social, relational, cultural, and contextual analysis of subjective experience. Studies of loneliness and possible relationships to mental health status require investigations of social, environmental, and institutional structures as well as families, peers, friends, counselors, and health providers. This article takes a step in this direction through examining the lived experience of 35 high school students and their families living under conditions of social adversity in Tijuana, B.C., Mexico, with attention to anxiety and depression. Utilizing ethnographic interviews, observations, and psychological screening tools, we provide an overview for the group and illustrate the interrelations of subjective experience and social environment through a case study. These data reveal the vital role of understandings of loneliness, depression, and anxiety from the perspectives of adolescents themselves. We conclude that future studies of loneliness are best informed by in-depth data on subjective experience in relation to social features to advance understandings within the field of global mental health and allied fields.
Assuntos
Ansiedade/etnologia , Depressão/etnologia , Relações Interpessoais , Solidão/psicologia , Transtornos Mentais/etnologia , Adolescente , Família/etnologia , Feminino , Saúde Global , Humanos , Masculino , Saúde Mental , México/etnologia , Inquéritos e QuestionáriosRESUMO
We conducted a preliminary RCT among 40 HIV-positive Latinos of Mexican descent on the U.S.-Mexico border who indicated imperfect adherence and depressive symptomatology. Participants were randomly assigned to culturally adapted cognitive-behavioral therapy for adherence and depression with an alarmed pillbox or usual care. Outcomes were depressive symptoms (self-report and blind clinician ratings), adherence (self-report and electronic pillbox), and biological markers. The intervention, delivered in English and Spanish, proved feasible and acceptable. Generalized estimating equations in intent-to-treat analyses showed some effects of "moderate" to "large" size, with maintenance over time. For example, intervention (vs. control) participants demonstrated at post-intervention a greater drop in BDI scores (OR = -3.64, p = 0.05) and greater adherence according to the electronic pillbox (OR = 3.78, p = 0.03). Biological markers indicated some relative improvement for CD4 count but not VL. The promising results suggest a larger trial to determine efficacy is warranted.
Assuntos
Terapia Cognitivo-Comportamental , Depressão/epidemiologia , Infecções por HIV/psicologia , Hispânico ou Latino , Adesão à Medicação/estatística & dados numéricos , Aceitação pelo Paciente de Cuidados de Saúde/estatística & dados numéricos , Adulto , Contagem de Linfócito CD4 , Depressão/tratamento farmacológico , Estudos de Viabilidade , Feminino , Infecções por HIV/tratamento farmacológico , Infecções por HIV/epidemiologia , Humanos , Masculino , Adesão à Medicação/psicologia , México/epidemiologia , Pessoa de Meia-Idade , Aceitação pelo Paciente de Cuidados de Saúde/psicologia , Cooperação do Paciente , Resultado do Tratamento , Estados Unidos/epidemiologia , Carga ViralRESUMO
El presente trabajo es un estudio descriptivo cuyo objetivo fue la caracterización de la prescripción de los antihistamínicos en la Consulta Externa en un hospital clase A, nacional, para adultos, de nuestro país; se estudiaron las recetas de antihistamínicos despachadas por el servicio de farmacia durante los meses de enero, febrero y marzo del año 2006. El Servicio de Farmacia del hospital estudiado durante el período despachó a 9260 recetas de antihistamínicos provenientes de la consulta externa. El antihistamínico con mayor prescripción fue el clorhidrato de fexofenadina, la cantidad prescrita superó dos veces la cantidad de hidroxicina, segundo antihistamínico de mayor prescripción. En un 12,75 por ciento del total de las recetas estudiadas se encontró la asociación de fexofenadina con otro antihistamínico de primera generación. El antihistamínico de primera generación que se asoció principalmente con la prescripción de fexofenadina fue hidroxicina, 64,4 por ciento, seguida de clorfeniramina, 30.6 por ciento y difenhidramina, 5.1 por ciento. Se tiene un costo estimado de 9369335.28; de este monto, al menos una cantidad cercana a los 443022.60 fue utilizada en la prescripción de antihistamínicos de primera generación, en forma conjunta con el clorhidrato de fexofenadina...