606 research outputs found
Antibióticos y daño en el DNA: una combinación peligrosa
El uso generalizado de antibióticos como agentes terapéuticos en humanos y animales y como promotores del crecimiento ha supuesto un gran desafío para las bacterias, lo que ha conducido a la selección y diseminación de variantes resistentes a los antibióticos. Sin embargo, los antibióticos parecen ser más que meros selectores de estas variantes. En los últimos años, se ha acumulado evidencia de que los antibióticos, además de su acción antimicrobiana, plantean potencialmente una serie de efectos secundarios no deseados, incluyendo la inestabilidad genómica en las bacterias. En consecuencia, el estrés producido por algunos antibióticos puede favorecer la promoción de la variabilidad genética y la diversidad en las bacterias, incluyendo la adquisición y evolución de la resistencia a los antibióticos.
Presentaré datos sobre cómo el estrés producido por los antibióticos afecta los mecanismos básicos involucrados en la reparación del ADN, como la ruta de reparación de desapareamientos y la respuesta SOS, aumentando la variación genética por la estimulación tanto de la mutación como la recombinación. Además, discutiré posibles estrategias para evitar o retrasar estos efectos secundarios durante los tratamientos con antibióticos.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
La reproducció en la vida de les dones. Aportacions de l'antropologia
L’antropologia social i cultural ha estudiat la reproducció des del punt de vista de diverses especialitats –parentiu, simbolisme, feminisme, salut– i ha assenyalat tant les dimensions que comprèn com el caràcter social, construït i central per al manteniment d’una societat. Aquesta mirada permet a les autores suggerir certes hipòtesis a partir de les quals entendre la reproducció com un assumpte vertebrador de la vida de les dones en l’actualidad, que hauria de ser objecte d’estudi rellevant per a la ciència
Effect of Sky Discretization for Shading Device Calculation on Building Energy Performance Simulations
The calculation of sunlit surfaces in a building has always been a relevant aspect in building energy simulation programs. Due to the high computational cost, some programs use algorithms for shading calculation for certain solar positions after discretization of hemispherical sky. The influence of the level of discretization on the estimation of incident direct radiation on building surfaces, as well as on the required computational times, are studied in this work. The direct solar energy on a window for a year, with simulation time steps of five minutes, has been simulated by using an algorithm based on Projection and Clipping Methods. A total of 6144 simulations have been carried out, varying window sizes, window orientations, typologies of shading devices, latitudes and discretization levels of the hemispherical sky. In terms of annual incident solar energy, the results show that maximum error values are about 5% for a low level of angular discretization. Errors up to 22% in hourly incident solar energy have been estimated for some of the configurations analysed. Furthermore, a great number of configurations show errors of shading factor on a window of up to 30%, which could be most relevant in studies of natural lighting. The study also shows that the improvement achieved by the most accurate discretization level implies an increase in computational cost of about 30 times
Molecular Mechanisms and Clinical Impact of Acquired and Intrinsic Fosfomycin Resistance
Bacterial infections caused by antibiotic-resistant isolates have become a major health problem in recent years, since they are very difficult to treat, leading to an increase in morbidity and mortality. Fosfomycin is a broad-spectrum bactericidal antibiotic that inhibits cell wall biosynthesis in both Gram-negative and Gram-positive bacteria. This antibiotic has a unique mechanism of action and inhibits the initial step in peptidoglycan biosynthesis by blocking the enzyme, MurA. Fosfomycin has been used successfully for the treatment of urinary tract infections for a long time, but the increased emergence of antibiotic resistance has made fosfomycin a suitable candidate for the treatment of infections caused by multidrug-resistant pathogens, especially in combination with other therapeutic partners. The acquisition of fosfomycin resistance could threaten the reintroduction of this antibiotic for the treatment of bacterial infection. Here, we analyse the mechanism of action and molecular mechanisms for the development of fosfomycin resistance, including the modification of the antibiotic target, reduced antibiotic uptake and antibiotic inactivation. In addition, we describe the role of each pathway in clinical isolates.This work was supported by the Ministerio de Economía y Competitividad, Instituto de Salud
Carlos III, co-financed by the European Development Regional Fund “A way to achieve Europe”
ERDF, Spanish Network for the Research in Infectious Diseases (REIPI RD12/0015 and FIS PI10/00105) and the PAR Project (Ref 241476) of the EU 7th Framework Programme
ACCA 015: Análisis y comunicación contemporánea de la arquitectura. José Joaquín Parra Bañón (Dir.)
Book reviewReseña de libr
Análisis de un problema de secuenciación en un taller de flujo con dos conjuntos de trabajos
En este presente documento se aborda el análisis de un problema de secuenciación en un taller de flujo con dos
máquinas y dos conjuntos de trabajos. Más concretamente, el objetivo es estudiar la resolución en un entorno
Flow Shop de un problema multicliente cuando los objetivos son la tardanza total y el tiempo de finalización
máximo.
Para llevar a cabo la investigación, se han configurado las baterías de problemas mediante un modelo de
programación lineal entera mixta capaz de resolverlas de manera eficiente. La creación de dicho modelo se ha
realizado mediante la herramienta MATLAB® mientras que la resolución de cada problema se ha efectuado
mediante el optimizador de GUROBI®.
Finalmente, se detallan los resultados obtenidos mediante tablas y se procede al análisis del tiempo
computacional de GUROBI®, así como al de los valores de las funciones objetivo.This document deals with the analysis of a two-agent scheduling problem in a two-machine flowshop. More
specifically, the goal is to study the resolution of a flowshop environment of a multi-agent problem when the
objectives are the total tardiness and the maximum completion time.
To carry out the research, the problem batteries have been configured using a mixed integer linear programming
model able to solve them efficiently. The creation of said model have been conducted using the MATLAB® tool,
while the resolution of each problem has been carried out using the GUROBI® optimizer.
Finally, the results obtained by means of tables are detailed and the computational time of GUROBI® is analyzed,
as well as that of the values of the objective functions.Universidad de Sevilla. Grado en Ingeniería de las Tecnologías Industriale
Structures in Time. The ruin in the work of Aires Mateus
El recorrido trazado a lo largo de este artículo se inicia en la célebre intervención de Manuel y Francisco Aires Mateus de Alenquer realizada en el año 1998 para comprobar que, después de veinte años de obras y proyectos, es posible vislumbrar una transferencia conceptual en torno a la idea del tiempo y la ruina que podrían estar apuntando hacia un asentamiento de ciertas estrategias ligadas al proyecto arquitectónico. Desde esta perspectiva podríamos observar algunas de sus construcciones como estructuras expuestas deliberadamente a recibir las huellas, inscripciones e incluso destrucciones acaecidas por el paso del tiempo.Over the last twenty years it is possible to understand a conceptual transference around the idea of time and ruin in some of the projects designed by architects Manuel and Francisco Aires Mateus. The path drawn along this article starts at the notorious intervention of Alenquer performed on 1998 in order to check, after the approach to some of theirs later projects, the possibility of analysing an evolution over the influence of the time in their works. From this perspective it is possible to observe some of their architectures as structures open to receive traces, inscriptions and even destructions due to the course of time
Series documentales para el estudio de las economías catedralicias
Estudiar la economía de una institución o de cualquier ente nos hace comprender mejor su funcionamiento, su historia y hasta el porqué de las decisiones que toman. Este trabajo se centra concretamente en la economía que incumbe a las catedrales españolas y que ya muchos otros autores han abordado. Pero la meta perseguida por este trabajo no es, ni la de hacer un estudio económico, ni la de hacer un estudio de las series documentales de carácter económico de las catedrales españolas per se. Realmente lo que perseguimos es llegar a establecer unas series documentales que sean capaces de abarcar toda la documentación de índole económica y que cada una de ellas sea válida para cualquier archivo de catedral español
Melanin-binding colorants: updating molecular modeling, staining and labeling mechanisms, and biomedical perspectives
Melanin and melanoma tumors are two fields of increasing interest in biomedical research.
Melanins are ubiquitous biopigments with adaptive value and multiple functions, and occur in the
malignant melanoma. Although several chemical structures have been proposed for eumelanin,
molecular modeling and orbitals indicate that a planar or spiral benzoquinone-porphycene polymer
would be the model that better explains the broad-band light and ultrasound absorption, electric
conductivity, and graphite-like organization shown by X-ray crystallography and electron microscopy.
Lysosomes and melanosomes are selectively labeled by vital probes, and melanin also binds to
metal cations, colorants, and drugs, with important consequences in pharmacology, pathology,
and melanoma therapy. In addition to traditional and recent oncologic treatments, photodynamic,
photothermal, and ultrasound protocols represent novel modalities for melanoma therapy. Since
eumelanin is practically the ideal photothermal and ultrasound sensitizer, the vibrational decay
from photo-excited electrons after NIR irradiation, or the electrochemical production of ROS and
radicals after ultrasound absorption, induce an efficient heating or oxidative response, resulting in
the damage and death of tumor cells. This allows repetitive treatments due to the remaining melanin
contained in tumoral melanophages. Given that evolution and prognosis of the advanced melanoma
is still a concern, new biophysical procedures based on melanin properties can now be developed
and applie
Aportaciones del Proyecto Votescript a los Esquemas Tradicionales de Voto Electrónico.
This paper hallmarks the most relevant contributions carried out by the authors in the VOTESCRIPT project (TIC2000-1630-C02). The main goal of this project was the analysis, definition and implementation of a system which copes with every phases and elements existing in a process of electronic voting using computer networks. A summary of the main criticisms of electronic voting is presented to disclose that the most relevant voting schemes only take into account a technological perspective, just trying to imitate the conventional voting schemes. Nevertheless in these proposals important aspects such individual and global verification are not properly undertaken. The paper
includes the proposed solutions of the project to solve these mentioned problems
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