Cyclization of interlocked fumaramides into ß-lactams: experimental and computational mechanistic assessment of the key intercomponent proton transfer and the stereocontrolling active pocket.

A detailed mechanistic study of the diastereoselective CsOH-promoted cyclization of interlocked fumaramides to give ß-lactams is described. The mechanistic analysis comprises the experimental evaluation of the structure-reactivity relationship for a wide range of fumaramides [2]rotaxanes (Hammet-plots), KIE studies with deuterium-labelled interlocked fumaramides and computational analysis of two alternative mechanistic pathways for the cyclization process. The obtained results confirm that: (a) the rate-determining step is the deprotonation of the N-benzyl group of the thread by the amidate group of the macrocycle generated by the external base, (b) the polyamide macrocycle plays an important role not only as activating element but also as the stereodifferenciating factor responsible for the observed diastereoselection and (c) the higher flexibility of the adamantyl core speeds up the cyclization process in diadamantyl-derived rotaxanes.

Assessment of postprandial triglycerides in clinical practice: Validation in a general population and coronary heart disease patients.

BACKGROUND: Previous studies have suggested that for clinical purposes, subjects with fasting triglycerides (TGs) between 89-180 mg/dl (1-2 mmol/l) would benefit from postprandial TGs testing. OBJECTIVE: To determine the postprandial TG response in 2 independent studies and validate who should benefit diagnostically from an oral-fat tolerance test (OFTT) in clinical practice. METHODS: A population of 1002 patients with coronary heart disease (CHD) from the CORDIOPREV clinical trial and 1115 white US subjects from the GOLDN study underwent OFTTs. Subjects were classified into 3 groups according to fasting cut points of TGs to predict the usefulness of OFTT: (1) TG < 89 mg/dl (<1 mmol/l); (2) TG, 89-180 mg/dl (1-2 mmol/l); and (3) TG > 180 mg/dl (>2 mmol/l). Postprandial TG concentration at any point > 220 mg/dl (>2.5 mmol/l) has been pre-established as an undesirable postprandial response. RESULTS: Of the total, 49% patients with CHD and 42% from the general population showed an undesirable response after the OFTT. The prevalence of undesirable postprandial TG in the CORDIOPREV clinical trial was 12.8, 50.3, and 89.7%, in group 1, 2, and 3, respectively (P < .001) and 11.2, 58.1, and 97.5% in group 1, 2, and 3, respectively (P < .001) in the GOLDN study. CONCLUSIONS: These two studies validate the predictive values reported in a previous consensus. Moreover, the findings of the CORDIOPREV and GOLDN studies show that an OFTT is useful to identify postprandial hyperlipidemia in subjects with fasting TG between 1-2 mmol/l (89-180 mg/dL), because approximately half of them have hidden postprandial hyperlipidemia, which may influence treatment. An OFTT does not provide additional information regarding postprandial hyperlipidemia in subjects with low TG (<1 mmol/l, <89 mg/dL) or increased TG (>2 mmol/l, >180 mg/dl).

Use of Natural-Fiber Bio-Composites in Construction versus Traditional Solutions: Operational and Embodied Energy Assessment.

During the last decades natural polymers have become more and more frequent to replace traditional inorganic stabilizers in building materials. The purpose of this research is to establish a comparison between the most conventional building material solutions for load-bearing walls and a type of biomaterial. This comparison will focus on load-bearing walls as used in a widespread type of twentieth century dwelling construction in Europe and still used in developing countries nowadays. To carry out this analysis, the structural and thermal insulation characteristics of different construction solutions are balanced. The tool used for this evaluation is the life cycle assessment throughout the whole lifespan of these buildings. This research aims to examine the environmental performance of each material assessed: fired clay brick masonry walls (BW), concrete block masonry walls (CW), and stabilized soil block masonry walls (SW) stabilized with natural fibers and alginates. These conventional and new materials are evaluated from the point of view of both operational and embodied energy.

Indicaciones y Valoración Clínica del Urocultivo y Coprocultivo

Objetivo: Evaluar la relevancia del uro y coprocultivo en la práctica clínica frecuente. Estrategia de búsqueda y selección de estudios: Se ha realizado una revisión bibliográfica en las bases de datos on-line Elsevier-Doyma y PubMed, de los artículos y guías de práctica clínica publicadas sobre este tema priorizando los trabajos realizados en América Latina. Selección de estudios y de datos: En la revisión se han incluido guías de la Sociedad Americana de Enfermedades Infecciosas (IDSA), manuales y guías de la Sociedad Española de Enfermedades Infecciosas, y los últimos artículos originales sobre este tema publicados en la región. Resultados: Escherichia coli continúa siendo el agente causal más frecuente tanto en urocultivo como en coprocultivo. En nuestro Hospital, han aumentado de forma importante las resistencias a antimicrobianos en especial a quinolonas. Conclusiones: La mayoría de los antibióticos utilizados como primera línea en la terapia empírica presentan elevados porcentajes de resistencias. En nuestro Hospital el antibiótico empírico de elección en infecciones urinarias fue levofloxacina en un 34,4% y ciprofloxacina en un 42%. En cuanto al coprocultivo la mayor resistencia presenta Eritromicina y Levofloxacina con 87,5%, seguido de Ampicilina con 76% de resistencia.

Abstract Aim: Evaluate the relevance of the urine culture and stool culture in common clinical practice. Search strategy and selection of studies: We performed a literature review on databases online Elsevier-Doyma and PubMed, articles and clinical practice guidelines published on this subject prioritizing work in Latin America. Study selection and data: The review included guides Infectious Diseases Society of America (IDSA), manuals and guides the Spanish Society of Infectious Diseases, and the last original published articles on this topic in the region. Results: Escherichia coli remains the most prevalent in both urine culture and coprocultivo causal agent. In our hospital, they have increased significantly the resistance to antibiotics especially quinolones. Conclusions: Most of the antibiotics used as first-line empiric therapy have high percentages of resistance. In our Hospital empirical antibiotic of choice in urinary tract infections was 34.4% levofloxacin and ciprofloxacin by 42%. Regarding coprocultivo presents greater resistance to erythromycin and Levofloxacin 87.5%, followed by 76% Ampicillin resistance