1,720,955 research outputs found
Biohidrogeles basados en complejos polielectrolitos como apósitos para heridas
Full text linkLos hidrogeles son materiales compuestos principalmente por una red polimérica y agua. Son reconocidos por su capacidad para absorber grandes cantidades de agua y por su aplicabilidad en diversos ámbitos. En el área biomédica, especialmente como apósitos para heridas, se utilizan debido a que permiten mantener niveles adecuados de humedad y temperatura, similares al ambiente corporal, favoreciendo el proceso de cicatrización, reduciendo tiempos y disminuyendo el riesgo de infecciones (Capítulo 1). Un tipo particular de hidrogel son los formulados mediante complejos polielectrolitos (PECs), donde una solución de polianión interactúa con una solución de policatión a través de sus grupos funcionales cargados. Cuando los hidrogeles se compactan, se los denomina complejos polielectrolitos compactos (CoPECs). La incorporación de sales como NaCl genera que los iones interactúen con las cadenas poliméricas, interfiriendo en la formación de la red y originando materiales saloplásticos con propiedades diferenciadas. En este trabajo se desarrollaron y caracterizaron hidrogeles CoPECs utilizando polímeros naturales. En los primeros capítulos se trabajó con los polisacáridos quitosano y pectina. Para la formulación se variaron parámetros como el pH, el contenido de NaCl y la concentración polimérica (los materiales y métodos se describen en el Capítulo 2). Se obtuvieron CoPECs de quitosano y pectina de forma satisfactoria e incorporaron NaCl en algunos casos para evaluar su efecto sobre las propiedades finales de los hidrogeles. Además, se añadió un analgésico modelo, la lidocaína, y se realizaron estudios específicos para evaluar su aplicación potencial como apósitos para heridas. Los resultados permitieron determinar que podrían utilizarse en quemaduras de primer o segundo grado (Capítulo 3). También se incorporaron refuerzos con el objetivo de mejorar las propiedades mecánicas y antimicrobianas de los hidrogeles. Los CoPECs de quitosano y pectina con nanohilos de celulosa (CNWs) demostraron resultados prometedores: los nanohilos se incorporaron de forma efectiva, mantuvieron el efecto antibacteriano, incrementaron la porosidad y los valores de tasa de transmisión de vapor de agua, y mejoraron las propiedades mecánicas superficiales (Capítulo 4). Por otro lado, se desarrollaron CoPECs de gelatina y condroitín sulfato con o sin NaCl. Los materiales obtenidos fueron compactos y frágiles, lo que dificultaba su moldeado y limitaba su uso como apósitos. Mediante un cambio en el proceso de obtención, empleando secado por aspersión en lugar de compactación por centrífuga, se lograron obtener microgeles de gelatina y condroitín sulfato. A estos microgeles se les incorporaron nanopartículas de plata (AgNPs), las cuales otorgaron propiedades antibacterianas. Además, se caracterizaron y analizaron otras propiedades de estos geles con miras a su uso en heridas agudas. En el ensayo de hemólisis, relacionado con su potencial aplicación, se observó que los microgeles con AgNPs presentaron un porcentaje de hemólisis mayor que los microgeles sin nanopartículas (Capítulo 5). En conclusión, este trabajo aborda la formulación, caracterización y estudio de biohidrogeles compuestos con aplicación potencial en apósitos para distintos tipos de heridas.Fil: Ferrante, Micaela. Universidad Nacional de Mar del Plata. Facultad de Ingeniería; Argentin
Current applications of biomolecules in biomedical engineering
No full textThis chapter discusses the various types of biomolecules and their roles in the structure and function of living organisms. Biomolecules can be classified into five categories: carbohydrates, proteins, lipids, vitamins, and nucleic acids. Each of these categories of biomolecules is formed by the chaining of monomers that are joined together by characteristic bonds. The chapter also explains the four generations of biomaterials and their unique properties such as bioactivity, biodegradability, and biocompatibility. Modification or functionalization of synthetic biomaterials with different bioactive molecules is of great interest as it provides them with unique biological activities. Biopolymers such as collagen, fibrin, and growth factors, as well as plant-based biomolecules such as cellulose, pectin, and alginate, can be used in several biomedical applications such as tissue engineering, medical regeneration, and drug delivery. The chapter aims to analyze the influence and importance of biomolecules in biomedical engineering and how they can be applied to take advantage of their properties.Fil: Ferrante, Micaela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Alvarez, Vera Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Gonzalez, Jimena Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentin
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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