Host-guest complexes to molecular encapsulation of hydrogen

Abstract only availableScience has always been about man learning from and attempting to mimic nature. In supramolecular chemistry this possibility is evident due to particularly interesting architectures of natural shell-like containers such as viruses and ferritin. One class of compounds studied for this purpose are calixarenes. Their typical cone structure allows them to sequester a variety of other molecules making it useful to form host-guest complexes or supramolecules. In such complexes, the host is a large molecule, in our case a calixarene, possessing a sizeable central cavity and the guest can be a monoatomic cation, a simple inorganic anion or a more sophisticated molecule such as a hormone, pheromone or neuro transmitter. In today's supramolecular chemistry field these compounds can be used for catalysis, biocatalysis, stabilization of reactive intermediates, drug transport, and the now emerging field of storage, processing and release of gases. The synthesis of this molecular capsule able to incorporate a guest begins with the methylation of the phenols present on the lower rim of calix[4]arene, an aldehyde was introduced along the upper ring followed by an oxidation to a carboxylic acid yielding tetracarboxycalix[4]arene. The tetrasubstituted calix[4]arene was crystallized from methanol and water to yield pale yellow crystals that were analyzed by X-ray. In this particular case, the objective was to incorporate gaseous hydrogen as the guest, which will be studied in due course. Further applications of this host-guest system could be the purification and storage of hydrogen for use in fuel cell. The nanoscale systems are a leading development strategy in many research areas. General advantages are the ability of saving time, space, costs, and materials for that reason supramolecular chemistry open a door to a new source of inspiration in the science world.Stevens' Chemistry Progra

Overflowing the Frame.Communication and Disaster in Latin America

En este artículo buscamos responder ¿qué se estudia cuando se analiza la relación entre comunicación y desastres en América Latina? Pesquisamos 52 artículos publicados a lo largo de casi dos décadas en 18 revistas académicas latinoamericanas. A partir de esta indagación identificamos cómo la respuesta a esta pregunta varía de acuerdo a marcos teóricos y metodológicos (y a las relaciones que se dan entre ambos), así como a los enfoques temporales y espaciales desarrollados.Para realizar el análisis leímos los artículos, los codificamos utilizando una matriz ad hoc y desarrollamos un análisis de las macro-proposiciones que emergieron. Esto nos posibilitó generar un estado del arte de las relaciones entre comunicación y desastres en Latinoamérica.Respecto de las conclusiones principales, rescatamos que la definición de comunicación, usualmente, se asienta en una perspectiva instrumental, que la entiende principalmente como emisión de mensajes. Consistente con lo anterior, identificamos que mayoritariamente el enfoque es de carácter mediocéntrico. Es decir, no se piensa a la comunicación como constitutiva de los fenómenos, sino más bien como un actor de segundo orden.Exploramos el camino recorrido por las investigaciones, caracterizamos sus principales aportes y proponemos una lectura, a la luz de la posibilidad de pensar la relación entre comunicación y desastres, desde la forma y fondo, y no tan solo desde una mirada agregativa de la comunicación hacia los desastres.What do we study when analyzing the relationship between communication and disasters in Latin America? We examined 52 articles published over almost two decades in 18 Latin American academic journals. Through this research, we were able to generate a state of the art of communication and disasters in the continent. We explored the path taken by the researchers, characterized their main contributions, and proposed a path to consider the relationship between communications and disasters from form and substance.Facultad de Periodismo y Comunicación Socia

Formar professores de Química para a inclusão escolar : uma experiência com o júri simulado no ensino superior

Apresentamos aqui um estudo sobre apropriação conceitual relacionado a temática inclusão escolar na formação docente em química, por meio da realização de uma atividade lúdica numa disciplina de núcleo livre: o júri simulado. Tal estratégia de ensino oportunizou realizar debates a partir das atuais contribuições da comunidade científica sobre a educação especial e as políticas públicas de inclusão escolar no Brasil com diferentes segmentos do curso de formação. Os resultados apontam que os argumentos construídos pelos sujeitos da investigação, produzem a contra-palavra a partir do conteúdo alvo da disciplina e que, quando solicitados a construir posicionamentos, comparando o discurso oficial (normativas legais brasileiras) e o discurso real (que se efetiva nas escolas regulares brasileiras), há apropriação conceitual expressa em suas produções discursivas

Rediscovery of the Yellow-bellied Sea Snake, Hydrophis platurus (Linnaeus, 1766) in Máncora, northern Perú

The presence of the Yellow-bellied Sea Snake (Hydrophis platurus) in the Southeast Pacific is rarely reported, with only one confirmed observation from northern Perú made in the early 1950s. We present new information based on a live-stranded specimen recently found in Peruvian waters, having washed ashore at Máncora (04.1255° S, 81.0958° W) in northern Perú on 12 July 2012. This stranding was associated with a Modoki El Niño warm event, since positive sea surface temperature (SST) anomalies up to 2.5°C were registered at this time

Effect of interleukin-1β on spinal cord nociceptive transmission of normal and monoarthritic rats after disruption of glial function

Introduction: Cytokines produced by spinal cord glia after peripheral injuries have a relevant role in the maintenance of pain states. Thus, while IL-1β is overexpressed in the spinal cords of animals submitted to experimental arthritis and other chronic pain models, intrathecal administration of IL-1β to healthy animals induces hyperalgesia and allodynia and enhances wind-up activity in dorsal horn neurons. Methods: To investigate the functional contribution of glial cells in the spinal cord nociceptive transmission, the effect of intrathecally administered IL-1β was studied in both normal and adjuvant-induced arthritic rats with or without glial inhibition. Four weeks after induction of monoarthritis, rats were treated with the glial cell inhibitor propentofylline (10 μg i.t. daily during 10 days) and submitted to a C-fiber-mediated reflex paradigm evoked by single and repetitive (wind-up) electric stimulation. Results: Both the propentofylline treatment and the monoarthritic condit

Desbordar el enfoque: Comunicación y Desastre en Latinoamérica

En este artículo buscamos responder ¿qué se estudia cuando se analiza la relación entre comunicación y desastres en América Latina? Pesquisamos 52 artículos publicados a lo largo de casi dos décadas en 18 revistas académicas latinoamericanas. A partir de esta indagación identificamos cómo la respuesta a esta pregunta varía de acuerdo a marcos teóricos y metodológicos (y a las relaciones que se dan entre ambos), así como a los enfoques temporales y espaciales desarrollados. Para realizar el análisis leímos los artículos, los codificamos utilizando una matriz ad hoc y desarrollamos un análisis de las macro-proposiciones que emergieron. Esto nos posibilitó generar un estado del arte de las relaciones entre comunicación y desastres en Latinoamérica. Respecto de las conclusiones principales, rescatamos que la definición de comunicación, usualmente, se asienta en una perspectiva instrumental, que la entiende principalmente como emisión de mensajes. Consistente con lo anterior, identificamos que mayoritariamente el enfoque es de carácter mediocéntrico. Es decir, no se piensa a la comunicación como constitutiva de los fenómenos, sino más bien como un actor de segundo orden. Exploramos el camino recorrido por las investigaciones, caracterizamos sus principales aportes y proponemos una lectura, a la luz de la posibilidad de pensar la relación entre comunicación y desastres, desde la forma y fondo, y no tan solo desde una mirada agregativa de la comunicación hacia los desastres.What do we study when analyzing the relationship between communication and disasters in Latin America? We examined 52 articles published over almost two decades in 18 Latin American academic journals. Through this research, we were able to generate a state of the art of communication and disasters in the continent. We explored the path taken by the researchers, characterized their main contributions, and proposed a path to consider the relationship between communications and disasters from form and substance

Severe Asthma: Updated Therapy Approach Based on Phenotype and Biomarker

Asthma is responsible for considerable global morbidity and health-care costs affecting over 300 million people worldwide. This illness is a heterogeneous condition characterized by chronic airway inflammation and pulmonary tissue remodeling resulting in a variety of clinical manifestations and treatment responses. Recent studies have shown an increasing appreciation of heterogeneity in asthma based on molecular phenotyping, biomarkers, and differential responses to therapies. In terms of asthma classification, perhaps the most important distinction to make is whether the patient has evidence of an eosinophilic inflammatory process characterized by type 2 immune response (Th2) or not. Therefore, personalized therapies to asthmatic patients just will be a reality by identifying and characterizing biomarkers. This review approaches the advances in diagnoses and management of asthma and severe asthma and highlights those with difficult-to-treat asthma based on each phenotype and biomarkers, to assist in the optimization of conventional therapy and to guide the use of targeted therapies

Design and Study of the Psychometric Properties of a Professors’ Expectations of Virtual University Education Questionary

This work describes the design and validation of a questionnaire to assess the expectations of higher education professors regarding virtual education (CEDVES). The sample included 546 professors, 299 men (54.66%) and 247 women (45.23%), from different scientific disciplines of a university in Chile. The final version consisted of 38 items answered using a five-point Likert scale. Nine factors were identified from the exploratory factor analysis. This configuration accounts for 75% of the variance. The structure of the instrument was studied using confirmatory factor analysis. It was found that nine factors produced a good fit, derived from a hierarchical solution in which all these factors depend on a factor of second general order. Each of the scales, like the general factor, present good indicators of reliability. The analysis indicates that this questionnaire has adequate validation and could be broadly used in higher education