1,720,972 research outputs found
Bionanoparticles, a green nanochemistry approach
Full text linkBackground: In the past decade, considerable attention has been paid for the development of novel
strategies for the synthesis of different kind of nano-objects. Most of the current strategies are usually working by the use physical or chemical principles to develop a myriad of nano-objects with multiple applications. Main fields of nanotechnology applications range from catalysis, micro- and nanoelectronics (semiconductors, single electrons transistors), non-linear optic devices, photoelectrochemistry to biomedicine, diagnostics, foods and environment, chemical analysis and others. Results: Two main avenues for nanoparticles synthesis: cell-free extract and cell cultivation have been reported. The state of art of both biotechnological approaches for different type nanoparticles are reviewed in this work. Conclusions: Nanotechnology is a revolutionary field just at its onset, the trend in the next decades being its integration with the green chemistry approach. Several strategies involving exhaustive strain selection, cultivation modes, recombinant gene expression, metabolic engineering, protein re-design and re-engineering, and predictive modeling will allow to create nanobioreactors, a new nanobiotechnology arena with a high potential impact in many fields.Fil: Cauerhff, Ana. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Biotecnología Aplicada. Laboratorio de Nanobiomateriales; Argentina;Fil: Castro, Guillermo Raul. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Biotecnología Aplicada. Laboratorio de Nanobiomateriales; Argentina
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
Relationship between structure, affinity and stability in the affinity maturation process of anti-lysozyme antibodies
No full textLa maduración de la afinidad es un mecanismo del sistema inmune de organismos superiores que modifica a un anticuerpo determinado con el fin de mejorar su afinidad por un antígeno determinado y así reconocerlo con mayor eficacia. Las consecuencias de la maduración de la afinidad fueron estudiadas en un sistema compuesto de dos anticuerpos monoclonales relacionados anti-lisozima, D44.1 y F10.6.6. Las mutaciones somáticas acumuladas en la región variable de F10.6.6 respecto de D44.1 produjeron cambios estructurales en el primero que incrementaron su afinidad hacia el antígeno en 700 veces. Mediante comparaciones de estructuras cristalinas, estudios cinéticos y termodinámicos de formación del complejo anticuerpo-lisozima, utilizando diversos fragmentos de anticuerpos generados en el laboratorio, se pudo determinar que la maduración de la afinidad de este sistema particular afecta la topología del sitio de combinación y la interacción en la interfaz VL-VH, la cual estabiliza al dominio variable de F10.6.6. Fue posible además identificar mediante el estudio de fragmentos de anticuerpo mutados aquellos residuos involucrados en la estabilización del dominio variable. Finalmente se postuló un mecanismo de maduración de la afinidad para el sistema D44.1-F10.6.6, donde las mutaciones introducidas actúan de modo conjunto para aumentar la afinidad y la estabilidad de F10.6.6.Affinity maturation of anti-protein antibodies is a complex mechanism of the immune system, which inserts random point mutations to a given antibody, improving its affinity towards the antigen. The affinity maturation effects were studied in a system composed of two closely related monoclonal antibodies, D44.1 and F10.6.6. Somatic mutations accumulated in the variable region of F10.6.6 modified its structure, increasing the affinity towards the antigen by 700 times related to D44.1. It was possible to observe by means of structure comparison, kinetic and thermodynamic studies of several antibody fragments, that the affinity maturation affects the topology of the combining site and improves the interacting surfaces, stabilizing the variable domain of F10.6.6. Also, the residues involved in structure stabilization were identified. Finally, an affinity maturation mechanism for this particular system was stated, in which all the mutations act as a whole, increasing both affinity and stability.Fil: Acierno, Juan Pablo. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina
Obtención y caracterización de anticuerpos monoclonales de isotipo IgM anti-lisozima de gallina
No full textLa inmunidad humoral es el mecanismo principal para la eliminación de microorganismos extracelulares y sus toxinas. Está mediada por anticuerpos (Acs)secretados por los linfocitos B (LB) circulantes y es la responsable del reconocimientoespecífico y la eliminación de los antígenos circulantes. La funcionalidad del sistemainmune humoral reside en su propiedad de producir un vasto rango de inmunoglobulinas distintas a partir de un repertorio genónmico limitado. En la primera etapa de la respuesta humoral primaria (primer encuentro del organismo con el antígeno foráneo), se producen anticuerpos de isotipo IgM, en unasegunda etapa se producen IgGs (IgGs tempranas). Para investigar algunos de losaspectos estructurales de las bases moleculares de la respuesta primaria hemoscaracterizado el AcMo FAAC79 y el AcMo Moi78 que reconocen en forma específicaa la lisozima de gallina (HEL). El primero fue obtenido en este plan y el segundofue producto de una fusión anterior. Ambos anticuerpos de isotipo IgM fueronpurificados a partir de LA, se ensayaron dos métodos de enriquecimiento, unode ellos fue la precipitación con agua a 4°C y otro método consistió en la precipitación con ácido bórico. Dichas IgMs fueron purificadas mediante precipitacióncon ácido bórico al 2% y exclusión molecular en FPLC, siendo éste el método que brindó mejor rendimiento. En un paso posterior se obtruvieron IgMm para estudios funcionales de afinidad frenteal antígeno mediante la técnica de biosensor a SPR. FAAC79 pudo ser caracterizadopresentando una kass de 6,35E3 M-1 S-1, una kdiss de 1.96E-3 s-1 y una KA de 1.89E6 M-1. el AcMo Moi78 no logró ser caracterizado debido a que no se pudoobtener una especie monovalente. Además hemos caracterizado sus estabilidades térmicas mediante DLS. Con el fin de establecer qué método de conservación y almacenamiento es el adecuado para los anticuerpos de isotipo IgM, hemos ensayado el agregadode trehalosa como crioprotector en el almacenamiento en solución a -20 °C y usando liofilización. Se evaluaron grado de agregación por DLS y actividad mediante ELISA. Considerando que el método de conservación tradicional es a -20°C se logró mejorar los resultados con el agregado de 0,2M de trehalosa como crioprotector y se encontró un método de conservación alternativo válidoque es la liofilización con el agregado de 0,8M de trehalosa. Además para completar la caracterización de dichos Acmos se procedió a clonary secuenciar su dominio variable mediante técnicas de Biología Molecular. Para el acMo Moi 78 hemos obtenido las secuencias de las cadenas VH y VLderivadas de las líneas germinales VH2c8, DQ52(BALB/c), JH3 y gm33, JK5respectivamente. VHMoi 78 presenta 9 mutaciones con respecto al gen VH2c8, 1de las cuales se encuentra en la juntura V-D (DQ52) y 7 inserciones (GGGGGGA) en el gen D, sin presentar mutaciones en el gen JH3. Para VL Moi 78 hemos econtrado 6 mutaciones con respecto al gen gm33, 2 de ellas en la juntura V-JK5 y 1 con respectoi al gen JK5. Desafortunadamente, no obtuvimos las secuencias codificantes para las cadenas VH y VL de FAAC79, pero fueron secuenciadas dos cadenas aberrantes derivadas de lascelulas NS0 usadas para obtener los anticuerpos monoclonales durante la fusión. Estos resultados están de acuerdo a otros previos aún no publicados por nuestro laboratorio.Fil: Molinari, Judith P.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina
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
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