Smart systems related to polypeptide sequences

Increasing interest for the application of polypeptide-based smart systems in the biomedical field has developed due to the advantages given by the peptidic sequence. This is due to characteristics of these systems, which include: biocompatibility, potential control of degradation, capability to provide a rich repertoire of biologically specific interactions, feasibility to self-assemble, possibility to combine different functionalities, and capability to give an environmentally responsive behavior. Recently, applications concerning the development of these systems are receiving greater attention since a targeted and programmable release of drugs (e.g. anti-cancer agents) can be achieved. Block copolymers are discussed due to their capability to render differently assembled architectures. Hybrid systems based on silica nanoparticles are also discussed. In both cases, the selected systems must be able to undergo fast changes in properties like solubility, shape, and dissociation or swelling capabilities. This review is structured in different chapters which explain the most recent advances on smart systems depending on the stimuli to which they are sensitive. Amphiphilic block copolymers based on polyanionic or polycationic peptides are, for example, typically employed for obtaining pH-responsive systems. Elastin-like polypeptides are usually used as thermoresponsive polymers, but performance can be increased by using techniques which utilize layer-by-layer electrostatic self-assembly. This approach offers a great potential to create multilayered systems, including nanocapsules, with different functionality. Recent strategies developed to get redox-, magnetic-, ultrasound-, enzyme-, light-and electric-responsive systems are extensively discussed. Finally, some indications concerning the possibilities of multi-responsive systems are discussed.Postprint (published version

Una Administración para donde vivimos. Análisis espacial de la realidad socio-demográfica y física del municipio de Jerez de la Frontera

Las características tanto físicas como económicas y sociales de sus barrios, de sus núcleos poblacionales, hacen que no podamos considerar sólo un perfil de persona residente en Jerez de la Frontera, ni de unas características típicas de las personas que viven en este municipio. No podemos hablar de un jerezano o jerezana medio, sino que en función del lugar en el que se reside dentro del municipio, las características demográficas, sociales, económicas de las personas, de la vivienda en la que residen y del hábitat en el que se desenvuelven pueden ser muy distintas. Se comprueba además que las personas cuya residencia habitual se sitúa en una determinada zona del municipio poseen circunstancias similares, y dependiendo del lugar en el que residen es posible predecir que la persona dispondrá de un cierto perfil socio-económico, y su vivienda y entorno físico, mostrarán unas características determinadas. Los responsables de las Administraciones Públicas tienen el deber de seleccionar e implantar aquellas políticas públicas que respondan a las competencias obligatorias que tienen atribuidas, que favorezcan el interés general y que desarrollen los principios de la Sociedad del Bienestar. Dichas políticas y las actuaciones en que se manifiesten deben ser pertinentes y atinadas respecto de las personas o colectivos a los que se dirigen, de modo que logren satisfacer con eficacia las necesidades que la ciudadanía presenta. Sin una adecuada base de información toda decisión que se tome no estará exenta de riesgo. En este trabajo se aflora, mediante el análisis con las herramientas informáticas disponibles y a través del estudio cuantitativo y espacial de los datos, la caracterización de las diferentes zonas de Jerez respecto de determinadas variables. Mediante análisis univariante se han estudiado y descrito las variables relacionadas con población, edad, nacionalidad, hogares, grado de urbanización, tipologías constructivas, categorías constructivas, dotación de zonas verdes, renta, afiliación a la Seguridad Social, pensiones y desempleo. Estas mismas variables disponen de datos que las hacen georeferenciables, por lo que se han podido plasmar, mediante los valores que toman en sendos mapas temáticos, que permiten comprobar de manera visual el desempeño de cada zona de Jerez respecto a la variable estudiada. De la combinación del análisis estadístico con el espacial, se han obtenido resultados que hasta ahora no constaban y que son muy valiosos para una correcta toma de decisiones. Con todo ello se posibilita que la actuación de la Administración Pública en Jerez se adecúe a las necesidades y circunstancias que la realidad presenta y donde las presenta.The physical, economic and social characteristics of its neighbourhoods, of its population centers, mean that we cannot only consider a profile of a person residing in Jerez de la Frontera, nor some typical characteristics of the people who live in this municipality. We cannot speak of an average man or woman from Jerez, but depending on the place where one resides within the municipality, the demographic, social, and economic characteristics of the people, the house in which they reside and the habitat in which they live can be very different. It is also verified that people whose habitual residence is located in a certain area of the municipality have similar circumstances, and depending on the place where they reside it is possible to predict that the person will have a certain socio-economic profile, and their home and physical environment will show certain characteristics. Responsible for Public Administrations have the duty to select and implement those public policies that respond to the mandatory powers that are attributed to them, that favor the general interest and that develop the principles of the Welfare Society. That policies and the actions in which they are manifested must be pertinent and accurate with respect to the people or groups to which they are addressed, so that they can effectively satisfy the needs that citizens present. Without an adequate information base, any decision taken will not be without risk. In this work, through the analysis with the available computer tools and through the quantitative and spatial study of the data, the characterization of the different areas of Jerez about to certain variables emerges. Through univariate analysis, variables related to population, age, nationality, households, degree of urbanization, construction typologies, construction categories, provision of green areas, income, affiliation to Social Security, pensions and unemployment have been studied and described. These same variables have data that make them georeferential, so they have been able to be captured, through the values they take in separate thematic maps, which allow visually checking the performance of each area of Jerez about the variable studied. From the combination of the statistical analysis with the spatial one, results until now not recorded have been obtained and are very valuable for correct decision making. With all this, it is possible for the actions of the Public Administration in Jerez to be adapted to the needs and circumstances that reality presents and where it presents

Eyectores para aplicaciones frigoríficas

El objeto de la tesis es el estudio de la refrigeración por eyección con el propósito de aprovechar calores residuales o fuentes alternativas (renovables) de energía. Partiendo de un exhaustivo análisis bibliográfico se ha desarrollado un modelo matemático para la predicción del comportamiento del eyector bajo determinados supuestos. Se realizaron dos instalaciones experimentales, una empleando aire y otra refrigerante para, por un lado, validar los resultados del modelo y, por otro, probar el funcionamiento de nuevas geometrías con el objeto de mejorar la eficiencia del eyector.Departamento de Ingeniería Energética y Fluidómecanic

De la abuelidad a la bisabuelidad. Explorando un rol familiar.

Background: In the light of the growing presence of a fourth generation in families, that of the great-grandparents, this study examines the interaction between individuals of this generation and their great-grandchildren taking into account their prior role as grandparents and certain sociodemographic characteristics.Methods: Descriptive study with 46 participants with great-grandchildren, who completed an interview that involved answering questions about sociodemographic variables and some of the most frequent intergenerational activities. The Wilcoxon, Kruskal-Wallis, and Mann-Whitney U nonparametric tests were used to analyze the data.Results: The data showed that 80.5% of the great-grandparents engage in interaction with their great-grandchildren in all the activities studied; further, these activities coincide with those previously shared with their grandchildren, albeit at a much lower rate. Age, the presence of health problems, and the number of great-grandchildren are related to a reduction in the frequency of certain shared activities between great-grandparents and great-grandchildren.Conclusions: The results of this initial study of the great-grandparenthood role can help show how this generation’s socializing role can be complementary to the other extended family roles of grandparenthood and parenthood. Our improved understanding of this role can help us better plan for optimizing interventions over the four generations.Antecedentesante el aumento continuo de una cuarta generación en las familias, los bisa-abuelos, se estudia su interacción con los bisnietos, teniendo en cuenta su rol precedente de abuelidad y algunas características sociodemográficas.Métodosestudio descriptivo con 46 participantes con bisnietos, a los que se entrevistó mediante un cuestionario que incluía variables sociodemográficas y algunas de las actividades intergeneracionales más frecuentes. Para analizar los datos se aplicaron las pruebas no paramétricas de Wilcoxon, Kruskal-Wallis y la U de Mann-Whitney.Resultadoslos datos muestran que el 80,5% de los bisabuelos mantienen una interacción con sus bisnietos en todas las actividades evaluadas; que coinciden, además, con las habidas con sus nietos, pero ahora con una frecuencia significativamente mucho menor. La edad, los problemas de salud y el número de bisnietos aparecen relacionados con la disminución de algunas actividades compartidas entre bisabuelos y bisnietos.Conclusioneslos resultados de este estudio inicial sobre el rol de bisabuelidad podrían servirnos para mostrar su papel socializador complementario al resto de la red familiar que forman los roles de abuelidad y parentalidad. Su mayor conocimiento nos podría ayudar a mejorar y optimizar intervenciones de 4 generaciones

Incorporation of biguanide compounds into poly(GL)-b-poly(GL-co-TMC-co-CL)-b-poly(GL) monofilament surgical sutures

A new biodegradable coating was developed for bioabsorbable monofilament sutures. Specifically, a random copolymer having 35 wt-% and 65 wt-% of lactide and trimethylene carbonate units showed appropriate flexibility, stickiness and degradation rate, as well as capability to produce a complete and uniform coating. Monofilament sutures of polyglycolide-b-poly(glycolide-co-trimethylene carbonate-co-e-caprolactone)-b-polyglycolide were loaded with chlorhexidine (CHX) and poly(hexamethylene biguanide) (PHMB) to explore the possibility to achieve antimicrobial activity without adverse cytotoxic effects. To this end, two processes based on single drug adsorption onto the suture surface and incorporation into the coating copolymer were used and subsequently evaluated. Although the second process could be considered more complex, clear benefits were observed in terms of drug loading efficiency, antimicrobial effect and even lack of cytotoxicity. In general, drugs could be loaded in an amount leading to a clear bacteriostatic effect for both Gram-negative and Gram-positive bacteria without causing significant cytotoxicity. Release profiles of PHMB and CHX were clearly different. Specifically, adsorption of the drug onto the fiber surface which prevented complete release was detected for PHMB. This polymer had advantages derived from its high molecular size, which hindered penetration into cells, thus resulting in lower cytotoxicity. Furthermore, bacterial growth kinetics measurements and bacterial adhesion assays showed greater effectiveness of this polymer.Peer ReviewedPostprint (author's final draft

Effect of hydroxyapatite nanoparticles on the degradability of random poly(butylene terephthalate-co-aliphatic dicarboxylate)s having a high content of terephthalic units

Copolyesters derived from 1,4-butanediol and constituted also of aliphatic and aromatic dicarboxylate units in a molar ratio of 3:7 were synthesized by a two-step polycondensation procedure. Succinic, adipic, and sebacic acids were specifically selected as the aliphatic component whereas terephthalic acid was chosen as the aromatic moiety. The second synthesis step was a thermal transesterification between the corresponding homopolymers, always attaining a random distribution as verified by NMR spectroscopy. Hybrid polymer composites containing 2.5 wt % of hydroxyapatite (HAp) were also prepared by in situ polymerization. Hydroxyl groups on the nanoparticle surface allowed the grafting of polymer chains in such a way that composites were mostly insoluble in the typical solvents of the parent copolyesters. HAp had some influence on crystallization from the melt, thermal stability, and mechanical properties. HAp also improved the biocompatibility of samples due to the presence of Ca2+ cations and the damping effect of phosphate groups. Interestingly, HAp resulted in a significant increase in the hydrophilicity of samples, which considerably affected both enzymatic and hydrolytic degradability. Slight differences were also found in the function of the dicarboxylic component, as the lowest degradation rates was found for the sample constituted of the most hydrophobic sebacic acid units. View Full-TextPeer ReviewedPostprint (published version

Biodegradability and biocompatibility of copoly(butylene sebacate-co-terephthalate)s

In the present study poly (butylene sebacate-co-terephthalate)s having different compositions were synthesized with a high yield and a random distribution by thermal transesterification of poly (butylene sebacate) and poly (butylene terephthalate) homopolymers. The copolymer with the highest comonomer ratio was the least crystalline sample, although the melting peaks corresponding to both, sebacate and terephthalate-rich phases were still observable in calorimetric heating runs. This copolymer was associated with interesting thermal and mechanical properties, as the maximum melting point was higher than 100 °C and the storage modulus was also high (i.e. 1.1 × 109 N/m2 and 1.7 108 N/m2 were determined just before and after the main glass transition temperature of -12 °C). As all studied samples were thermally stable up to temperatures clearly higher than the fusion temperature, they could be easily processed. Increasing the terephthalate content of the copolymers resulted in higher hydrophobicity, which had a minor influence on cell adhesion and proliferation of both fibroblast-like and epithelial-like cells. Hydrolytic and enzymatic degradability were assessed and the effect of composition and crystallinity on the degradation rate was investigated. Molecular weight measurements during exposure to a hydrolytic media indicated a first order kinetic mechanism during the initial stages of degradation before reaching a limiting molecular size, which was indicative of solubilization. The most amorphous sample appears as a highly promising biodegradable material since it showed a significant weight loss during exposure to all selected degradation media, but also exhibited good performance and properties that were comparable to those characteristic of polyethylenePeer ReviewedPostprint (author's final draft

Receptor de GPS experimental para satélites de órbita baja

En este trabajo se presenta el diseño, la implementación y la validación de un receptor de GPS capaz de operar en un satélite de baja órbita. Se desarrolló tanto el hardware como el software necesario debiendo recurrir a diversas técnicas como diseño de circuitos de radio frecuencia y circuitos impresos para señales de alta velocidad, sincronización de señales de comunicaciones digitales, diseño de software de tiempo real y algoritmos de estimación no lineal. El desarrollo completo de un receptor de GPS con estas características, resultado de más de 10 años de trayectoria en la temática del grupo de trabajo, pone en evidencia el nivel de desarrollo que puede tener la electrónica realizada en el país. El receptor fue implementado y probado, pudiéndose verificar su correcto funcionamiento. Se muestran algunas de las pruebas realizadas, por simulación y con mediciones reales, que permitieron validar distintas etapas del diseño. Actualmente, este receptor forma parte del satélite argentino SAC-D de la CONAE a ser puesto en órbita en 2011