Mesoporous niobium oxide for dehydration of D-xylose into furfural

Se ha demostrado que el óxido de niobio mesoporoso es un catalizador eficaz para la deshidratación de D-xilosa a furfural, alcanzando una conversión del 92% y un rendimiento de furfural 49,3% a 170º C y 90 minutos. La lixiviación de Nb, determinada por ICP-MS, era inferior al 0,5% en peso de la concentración de Nb inicial, confirmando de este modo la estabilidad del catalizador ácido sólido.El furfural posee un gran potencial como molécula plataforma de origen renovable para la síntesis de una alta variedad de compuestos químicos. Se obtiene mediante la deshidratación de pentosas, principalmente a partir de D-xilosa, proceso catalizado por ácidos minerales en fase homogénea. Por tanto, dentro de la química verde y la búsqueda de sostenibilidad de los procesos catalíticos, es necesaria su sustitución por catalizadores sólidos ácidos que sean tolerantes al agua, ya que es el disolvente más utilizado para esta reacción. El óxido de niobio posee propiedades ácidas y es insoluble en agua, pero su superficie específica es muy baja. Por lo tanto, resulta muy interesante la síntesis de un óxido de niobio mesoporoso para emplearlo como catalizador en esta reacción. En este trabajo, se ha sintetizado un Nb2O5 mesoporoso y se ha evaluado su comportamiento catalítico en la obtención de furfural a partir de D-xilosa.Spanish Ministry of Science and Innovation (ENE2009-12743-C04-03 project)Junta de Andalucía (P09-FQM-5070).Ministry of Science and Innovation for the financial support under the Program Ramón y Cajal (RYC-2008-03387)

Depresión perimenopáusica: una revisión

A partir de la adolescencia, las mujeres presentan un riesgo 1,5 a 3 veces mayor que los hombres de padecer un trastorno depresivo. Este riesgo aumenta en el periodo de transición hacia la menopausia o perimenopausia, cuando la vulnerabilidad depresiva se hace especialmente intensa. Se han postulado mecanismos hormonales, psicológicos y socioculturales para entender la etiopatogenia de estos cuadros. El tratamiento de la depresión en la perimenopausia viene determinado por la gravedad clínica e incluye antidepresivos, psicoterapia y, en ocasiones, terapia hormonal sustitutiva mediante estrógenos. La depresión perimenopáusica constituye un problema infradiagnosticado e infratratado, que genera un alto nivel de sufrimiento y que merece una mayor atención por parte de los clínicos y el sistema sanitario

Ganancia Genética Esperada de la Resistencia a Sarna Somún (Streptomyces spp.) en una Población de Solanum phureja Juz. et Buk.

La sarna común de la papa, causada por bacterias del género Streptomycetes, es una enfermedad de difícil manejo agronómico que se encuentra en todas las zonas de producción de papa en el mundo, por lo que la obtención de cultivares resistentes a la enfermedad es uno de los componentes del manejo integrado de la enfermedad. Hasta ahora se han obtenido algunos materiales resistentes en Estados unidos y Europa; no obstante los estudios genéticos realizados hasta ahora para determinar caracteres como la heredabilidad han dado pocos resultados que puedan ser utilizados para el mejoramiento genético. El presente estudio se realizó con la finalidad de estimar los parámetros genéticos de la resistencia a sarna común utilizando una po­blación de 38 familias de medios hermanos de Solanum phureja en campo, en cuatro localidades diferentes del departamento de Antioquia (Colombia). Los resultados muestran que tres localidades fueron aptas para el análisis de los resultados por presentar diferentes niveles de severidad en los genotipos la otra localidad presentó un bajo nivel de severidad de la enfermedad lo que no permitió realizar una correcta selección. La heredabilidad en sentido estrecho osciló entre 0,22 y 0,45 para las localidades discriminantes. Se encontró una alta variación en la respuesta del genotipo al ambiente en la expresión de la resistencia genética. La ga­nancia genética esperada puede ser hasta del 20% de disminución en severidad de la enfermedad por ciclo de selección, lo cual indica que el carácter de resistencia a sarna común puede ser manejado en programas convencionales de mejoramiento genético mediante esquemas de selección recurrente

Catatonía, a propósito de un caso.

Presentamos un cuadro clínico de mutismo, acinesia y estupor con fiebre y retención urinaria en una mujer de 65 años como ejemplo de catatonia. La sintomatología catatónica se ha establecido como un síndrome común a múltiples etiologías tanto médicas como psiquiátricas. Además se han descrito factores precipitantes de tipo farmacológico, tóxico y orgánico para esta entidad. Por tanto, es necesaria una aproximación multidisciplinar a este tipo de cuadros para afinar el diagnóstico etiológico. Varios autores apuntan a un infradiagnóstico de este síndrome. Durante la evaluación, diagnóstico y tratamiento de esta paciente, hallamos la necesidad de criterios diagnósticos claros y actualizados y de algoritmos de tratamiento basados en evidencias. Las benzodiazepinas y la terapia electroconvulsiva suponen el tratamiento de primera línea, junto con las medidas de soporte y la prevención de complicaciones. Se han publicado otras estrategias no protocolizadas de tratamiento alternativas en casos refractarios

Health of Spanish centenarians: A cross-sectional study based on electronic health records

Background: With the number of centenarians increasing exponentially in Spain, a deeper knowledge of their socio-demographic, clinical, and healthcare use characteristics is important to better understand the health profile of the very elderly. Methods: We conducted a retrospective, cross-sectional observational study in the EpiChron Cohort (Aragon, Spain) aimed at analyzing the socio-demographic, clinical, drug use and healthcare use characteristics of 1680 centenarians during 2011-2015, using data from electronic health records and clinical-administrative databases. Results: Spanish centenarians (79.1% women) had 101.6 years on average. Approximately 80% of centenarians suffered from multimorbidity, with an average of 4.0 chronic conditions; 50% were exposed to polypharmacy, with an average of 4.8 medications; only 6% of centenarians were free of chronic diseases and only 7% were not on medication. Centenarians presented a cardio-cerebrovascular pattern in which hypertension, heart failure, cerebrovascular disease and dementia were the most frequent conditions. Primary care was the most frequently visited healthcare level (79% of them), followed by medical specialist consultations (23%), hospitalizations (13%), and emergency service use (9%). Conclusions: Multimorbidity is the rule rather than the exception in Spanish centenarians. Addressing medical care in the very elderly from a holistic geriatric view is critical in order to preserve their health, and avoid the negative effects of polypharmacy

Do centenarians die healthier than younger elders? A comparative epidemiological study in Spain

This study aims to describe the clinical course, drug use, and health services use characteristics during the last year of life of elders who die being centenarians and to identify key aspects differentiating them from elders who die at an earlier age, with a particular focus on sex differences. We conducted an observational, population-based study in the EpiChron Cohort (Aragon, Spain). The population was stratified by sex and into three age sub-populations (80-89, 90-99, and >= 100 years), and their characteristics were described and compared. Multimorbidity was the rule in our elders, affecting up to 3 in 4 centenarians and 9 in 10 octogenarians and nonagenarians. Polypharmacy was also observed in half of the centenarian population and in most of the younger elders. Risk factors for cardiovascular disease (i.e., hypertension, dyslipidaemia, diabetes), cerebrovascular disease and dementia were amongst the most common chronic conditions in all age groups, whereas the gastroprotective drugs and antithrombotic agents were the most dispensed drugs. Centenarians presented in general lower morbidity and treatment burden and lower use of both primary and hospital healthcare services than octogenarians and nonagenarians, suggesting a better health status. Sex-differences in their clinical characteristics were more striking in octogenarians and tended to decrease with age

Biosensors Used for Quantification of Nitrates in Plants

Nitrogen is essential for the plant because it is used for the production of chlorophyll, proteins, nucleic acids, amino acids, and other cellular compounds; nitrogen is available in two forms: ammonium and nitrate. Several tools have been used to quantify nitrates in plants such as the Kjeldahl method and Dumas combustion digestion; however, they are destructive and long time-consuming methods. To solve these disadvantages, methods such as selective electrodes, optical sensors, reflectometers, and images based sensors have been developed; nonetheless, all these techniques show interference when carrying out measurements. Currently, biosensors based on genetic constructions, based on the response of promoter gene fused to Gene Fluorescent Protein (GFP), are gaining popularity, because they improve the accuracy of measurements of nitrate by avoiding the interference of carriers ion, high salt conditions, and other factors. The present review shows the different methods to quantify the nitrogen in plants; later, a biosensors perspective is presented, mainly focused on biosensors based on organism genetically modified. The review presents a list of promoter and reporter genes that could be used to develop different kind of sensors, and a perspective of sensors to measure quantitatively the nitrogen is presented

The state of international collaboration for health systems research: what do publications tell?

AIM: International collaboration for health system development has been identified as a critical input to meet pressing global health needs. North-South collaboration has the potential to benefit both parties, while South-South collaboration offers promise to strengthen capacity rapidly and efficiently across developing countries. There is an emerging trend to analyze the fruits of such collaboration. This paper builds on this trend by applying an innovative concept-based bibliometric method to identify the international scope of collaboration within the field of health policy and systems research. Two key questions are addressed: to what extent are papers comparing developing countries as against reporting on single country studies? To what extent are papers in either case being produced by researchers within their respective countries or through North-South or South-South collaboration? METHODS: A total of 8,751 papers published in Medline between 1999 and 2003 with data on health systems and policies in developing countries were identified and content-analyzed using an innovative concept-based search technology. A sample of 13% of papers was used to identify the corresponding institution and countries covered. The sampled data was then analyzed by income group. RESULTS: Papers with an international, cross-country focus account for only 10% of the total. Just over a third of all papers are led by upper middle income country authors, closely followed by authors from high income countries. Just under half of all papers target low income countries. Cross-country papers are led mostly by institutions in high income countries, with 74% of the total. Only seven countries concentrate 60% of the papers led by developing country institutions. Institutions in the United States and the United Kingdom concentrate between them as many as 68% of the papers led by high income countries. Only 11% of all single-country papers and 21% of multi-country studies are the product of South-South collaboration. Health Financing is the topic with the greatest international scope, with 26% of all papers in the topic. Topics such as Costing and Cost Effectiveness, Finance, Sector Analysis and Insurance, regardless of their national or international scope, are led in 38% to 54% of cases by high income authors. CONCLUSION: While there is modest health systems research capacity in many developing countries for single country studies, capacity is severely limited for multi-country studies. While North-South collaboration is important, the number of international studies is still very limited to produce the kind of knowledge required to learn from experiences across countries. The fact that lead institutions as well as study countries are concentrated in a handful of mostly middle income countries attests to great disparities in research capacity. However, disparities in research capacity and interest are also evident in the North. It is urgent to build cross-country research capacity including appropriate forms of South-South and North-South collaboration