1,721,068 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Caracterización de dos formulaciones vacunales como sistemas de liberación en mucosas de la quimera BLSOmp31 : evaluación de la inmunogenicidad y de la protección conferida contra Brucella ovis en el ovino
No full textBrucella ovis (B. ovis) es el agente causal de la epididimitis contagiosa del carnero
(ECC), principal causa de problemas reproductivos en establecimientos de cría ovina. Si
bien la cepa atenuada Brucella melitensis Rev.1 se emplea como herramienta preventiva,
presenta numerosas desventajas, por lo cual es necesario el desarrollo de vacunas
subcelulares que soslayen estos inconvenientes. Además, dado que B. ovis inicia el proceso
infeccioso en la superficie mucosa, una respuesta inmunitaria local protectora constituye un
desafío interesante en el desarrollo de vacunas. La quimera BLSOmp31 formulada en
adyuvante oleoso y administrada vía parenteral como proteína indujo niveles de anticuerpos
e interferón gamma elevados y confirió protección significativa contra el desafío con B.
ovis (75%). La vacunación en las mucosas genera una respuesta inmunitaria específica de
tipo secretoria y de memoria en el sitio de aplicación del inmunógeno, en otras mucosas y a
nivel sistémico. Para lograr una eficaz y sólida respuesta inmunitaria en las mucosas, es
crítica la vía de administración de la vacuna subcelular y a su vez el empleo de sistemas de
liberación o entrega del inmunógeno que sean adecuados, y/o el uso de potentes
adyuvantes. En el presente proyecto de Tesis se diseñaron y caracterizaron formulaciones
vacunales basadas en el empleo de la quimera BLSOmp31 para su posterior administración
en las mucosas nasal y/o conjuntival del macho ovino. Se evaluó la respuesta humoral y
celular (in vivo e in vitro) y la protección conferida contra la cepa virulenta de referencia B.
ovis PA76250 mediante el análisis bacteriológico de órganos del tracto reproductor y del
sistema fagocítico mononuclear. Se emplearon como sistemas de liberación microesferas de
quitosano producidas mediante secado por “spray” y geles termosensibles de Poloxamer
P407 para la administración por la vía intranasal y por la vía intranasal y conjuntival
respectivamente. Los resultados obtenidos demuestran que las estrategias empleadas
indujeron una respuesta humoral y celular que protegió parcialmente contra B. ovis,
teniendo en cuenta la proporción de órganos infectados y el número de UFC aislado de los
órganos muestreados. Cabe destacar que estos sistemas de inmunización redujeron el
porcentaje de infección y el número de bacterias por órgano en un nivel similar al grupo
control BLSOmp31-AFI.Fil: Díaz, Alejandra Graciela. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Veterinarias; Argentina.Fil: Estein, Silvia Marcela. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Veterinarias; Argentina.Fil: Goldbaum, Fernando Alberto. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Veterinarias; Argentina.Brucella ovis is the etiologic agent of ovine brucellosis, which causes significant
reproductive disorders in flocks worldwide. Immunization with B. melitensis Rev 1 gives
protection against B. ovis but it has important disadvantages. Consequently, there is a need
for new brucellosis vaccines to be developed for overcoming these drawbacks. In addition,
B. ovis initiates its infectious process at mucosal surfaces thus, achieving a local immune
response is an interesting point to consider in the development of vaccines. The polimeryc
antigen BLSOmp31 formulated with Incomplete Freund Adjuvant (IFA) parenterally
administered induced high levels of specific IgG antibodies gamma interferon and was
significantly protective against B. ovis experimental infection. Mucosal immunization
compared to parenteral route is able to induce a secretory specific immune response in the
site of immunization and in distant mucosal sites. Also, it is capable of inducing a systemic
immune response and memory T cells. In order to obtain a solid and efficient immune
response at mucosal surfaces is critical the immunization route and also the use of an
adequate delivery system and/or potent adjuvants. In the present Thesis it was proposed to
develop and characterize vaccine formulations based all of them in the use of chimeric
BLSOmp31 for administration at nasal and conjunctival mucosae. These vaccine
formulations were administered to lambs in order to study the humoral and cellular immune
response and the conferred protection against a virulent strain of B. ovis. In addition, it may
contribute to understanding the mechanisms involved in the immune response in sheep. As
delivery system were used chitosan microspheres obtained by the spray dried technique and
thermosensitive gel of poloxamer. Formulation based on chitosan microspheres was
intranasally administered and those of poloxamer gel were administered at nasal and
conjunctival mucosa. The results of this Thesis show that the strategy of immunization used
in the study were able to induce a humoral and cellular immune response which was
partially protective against experimental challenge against B. ovis, if the proportion of
infected organs and the CFU/organ are considered. It is remarkable that both immunization
systems reduced the percentage of infection and the number of bacteria per organ at similar
levels to the control vaccine BLSOmp31 formulated with IFA
Variations on the Author
Get PDF“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
Get PDFWe 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
The art of blocking ADP-ribosyltransferases (ARTs): nanobodies as experimental and therapeutic tools to block mammalian and toxin ARTs
Get PDFIn 1901, the first Nobel Prize in Physiology or Medicine was awarded to Emil von Behring for his ground-breaking discovery of serum therapy: serum from horses vaccinated with toxin-containing culture medium of Corynebacterium diphtheriae contained life-saving 'antitoxins'. The molecular nature of the ADP-ribosylating toxin and the neutralizing antibodies were unraveled only 50 years later. Today, von Behring's antibody therapy is being refined with a new generation of recombinant antibodies and antibody fragments. Nanobodies, which are single-domain antibodies derived from the peculiar heavy-chain antibodies of llamas and other camelids, are emerging as a promising new class of highly specific enzyme inhibitors. In this review, we illustrate the potential of nanobodies as tools to block extracellular and intracellular ADP-ribosyltransferases (ARTs), using the toxin-related membrane-bound mammalian ecto-enzyme ARTC2 and the actin-ADP-ribosylating Salmonella virulence plasmid factor B toxin of Salmonella enterica as examples.Fil: Menzel, Stephan. University Medical Center Hamburg-Eppendorf; AlemaniaFil: Rissiek, Björn. University Medical Center Hamburg-Eppendorf; AlemaniaFil: Haag, Friedrich. University Medical Center Hamburg-Eppendorf; AlemaniaFil: Goldbaum, Fernando Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Koch Nolte, Friedrich. University Medical Center Hamburg-Eppendorf; Alemani
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
Study of flavin synthesis in Brucella abortus as a potential therapeutic target against brucellosis
Get PDFLos miembros del género Brucella son bacterias Gram-negativas intracelulares facultativas que se adaptan a la vida intracelular en una gran variedad de mamíferos. Brucella spp causan brucelosis, la zoonosis de mayor incidencia en el mundo que afecta al ganado y a humanos, y para la cual aún no se dispone de una vacuna segura y confiable. A pesar de que Brucella no presenta factores de virulencia clásicos, exhibe una gran flexibilidad metabólica la cual le permite adaptar su fisiología en respuesta a los distintos microambientes encontrados durante su ciclo de vida intracelular. Esta adaptación fisiológica se basa en un ágil ajuste de la expresión de distintos subconjuntos de genes, entre los que se encuentran aquellos involucrados en el metabolismo de flavinas. La riboflavina (vitamina B2) es el precursor de FMN y FAD, dos cofactores esenciales que están implicados en una amplia variedad de procesos celulares en todos los organismos. Esta vitamina es sintetizada en microorganismos y plantas, pero no en humanos y animales, los cuales deben adquirirla a través de su dieta. Los dos últimos pasos de la biosíntesis de riboflavina son catalizados por las enzimas Lumazina Sintasa (LS) y Riboflavina Sintasa (RS). Debido a la ausencia de esta vía metabólica en animales y el hecho de que las bacterias patógenas muestran una estricta dependencia de su biosíntesis de riboflavina, se ha propuesto a LS y RS como dianas potenciales para el desarrollo de fármacos antimicrobianos. En este trabajo se presentan datos que sugieren una regulación diferencial de los genes involucrados en la biosíntesis de riboflavina en B. abortus. Asimismo, se resolvió la estructura cristalográfica de RS de B. abortus unida al producto de reacción riboflavina y a dos análogos de producto. Para complementar estos resultados, se realizaron también estudios cinéticos y de unión sobre RS; y se llevó a cabo un ensayo de high throughput screening de microelectroforesis capilar de una biblioteca de 44.000 compuestos en colaboración con la empresa farmacéutica Novartis en Suiza. A partir de éste se identificaron diez compuestos con potencia micromolar del cual se identificó una serie de cinco compuestos con actividad in vivo contra B. abortus en cultivo bacteriano. En conclusión, la determinación de nuevas estructuras de RS unida a ligandos, su caracterización bioquímica y el hallazgo de nuevos inhibidores con actividad contra B. abortus in vivo representan un avance en la búsqueda de los antimicrobianos contra la brucelosis.Brucella spp. are facultative intracellular Gram-negative bacteria, which are adapted to intracellular life within cells of a large variety of mammals. They cause brucellosis, a zoonotic infection with the highest incidence in the world affecting livestock and humans and for which a safe and completely reliable vaccine is still unavailable. Although Brucella has not classical virulence factors, it exhibits high metabolic flexibility, which allows it to adapt its physiology in response to different microenvironments found during its intracellular life cycle. This physiological adaptation is based on a flexible adjust of the expression of different subsets of genes, among which are those involved in the metabolism of flavins. Riboflavin (vitamin B2) is the precursor of FMN and FAD, two essential cofactors for all organisms that are involved in a wide variety of cellular processes. This vitamin is biosynthesized in microorganisms and plants but not in humans and animals, which must acquire it through their diet. The last two steps of riboflavin biosynthesis are catalyzed by Lumazine Synthase (LS) and Riboflavin Synthase (RS). Owing to the absence of this pathway in animals and the fact that most pathogenic bacteria show a strict dependence on riboflavin biosynthesis, it has been proposed that these enzymes may be promising targets for the development of new antimicrobial agents for the treatment of brucellosis. In this work, we show data that suggest a differential regulation of genes involved in the biosynthesis of riboflavin in B. abortus. Furthermore, we present the crystallographic structure of RS from B. abortus. In order to describe its substratebinding sites, we solved the structure of the enzyme in the presence of bound ligands, namely one of the products of the reaction (riboflavin) and two product analogues. To complement these findings, we performed kinetic and binding studies on the enzyme. A newly High-throughput Screening capillary electrophoresis assay of 44.000 compounds library was developed in collaboration with Novartis in Switzerland, which identified 10 compounds with micromolar potency. From this subset we identified a series of 5 compounds with in vivo activity against B. abortus. In conclusion, these newly determined structures, biochemical characterization of RS and finding of novel inhibitors with activity against B. abortus represent a progress in the pursuit of antimicrobial compounds against brucellosis.Fil:Serer, María Inés. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina
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