1,720,964 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
Role of lamin A/C in the cellular features of age-related bone loss
No full textLamin A/C, an important component of the nuclear envelope, has been associated with cell differentiation and tissue development. In bone, recent studies have described that altered function of lamin A/C, due to mutations or incorrect processing, is associated with accelerated and severe bone loss. This could be due to alterations in the differentiation of mesenchymal stem cells (MSC) induced by lack of lamin A/C activity. Therefore, considering that decreased osteoblastogenesis and increased adipogenesis are the characteristic changes observed within bone marrow microenvironment that leads to age-related bone loss, we have studied the effect of inhibition of lamin A/C on MSC into either osteoblasts or adipocytes both in vitro and in vivo. For in vitro studies, we identified the effect of pharmacological inhibition of lamin A/C on adipogenesis. Subsequently, we inhibited lamin A/C by using different doses of lamin A/C siRNA in osteogenic and adipogenic differentiating MSCs as well as normal human osteoblasts. To further verify our results, we have used Zmpste24-/- null progeroid mice that lacks mature lamin A/C and studied the bone changes in absence of mature lamin A/C in in vivo. We have found that partial inhibition of lamin A/C decreased osteoblast differention and function without affecting their survival. Furthermore, our animal studies showed that absence of mature lamin A/C induced a reduction in bone mass and bone quality associated with low bone turnover. In contrast, accumulation of prelamin A induced significant levels of adipogenesis within the bone marrow cavity. In summary, our results provide evidence in support of a pivotal role of lamin A/C in the commLamin A/C, un important composant de l'enveloppe nucléaire, a été associé avec la différentiation cellulaire et le développement tissulaire. Dans l'os, des études récentes ont demontrée que l'alteration de lamin A/C, due a des mutations du gène LMNA, est associée avec une perte accélérée et sevère de l'os. Ceci pourrait être dû à une altération de la différentiation des cellules souches mésenchymateuses (CSM) induit par une perte de l'activité de lamin A/C. Par conséquent, en considerant que la diminution de l'ostéoblastogènese et l'augmentation de l'adipogènese sont les changements caractéristiques observés à l'intérieur du micro-environnement de la moelle osseuse qui mènent à une perte osseuse relié à l'âge, nous avons étudié l'effet de l'inhibition de lamin A/C sur la différentiation des cellules souches soit en adipocyte ou en ostéoblast in vitro et in vivo. Pour les études in vitro, nous avons identifiés l'effet de l'inhibition pharmacologique de lamin A/C sur l'adipogènese. Par la suite, nous avons inhibé lamin A/C en utilisant différentes doses de lamin A/C siRNA sur les cellules souches en différentiatiation en ostéoblast et en adipocytes et aussi sur des ostéoblast humaine. Pour confirmer nos résultats précedents, nous avons utilisés un modèle progerique murin Zmste24-/-. Ces souris ne possedent pas la forme mature de lamin A/C. Nous avons etudiés les changements osseux en absence de la forme mature de lamin A/C in vivo. Nous avons trouvé qu'une inhibition partielle de lamin A/C diminue la différentiation et la fonction des ostéoblastes sans affecter leur survie. En outre, nos études sur les souris ont
Describing the Cell Biology of Saprolegnia parasitica: Role of Metals and Respiration
No full textSaprolegnia parasitica is a pathogenic oomycete that causes saprolegniasis, a serious disease affecting freshwater fish and aquaculture systems. Despite the increasing use of copper-based treatments to control this infection, little is known about how S. parasitica responds to fluctuations in metal availability at the physiological and mitochondrial levels. This study investigates the impact of copper and iron availability on Saprolegnia parasitica growth, metal uptake, and respiratory function. We cultured S. parasitica in chemically defined media supplemented with or depleted of essential metals using specific chelators— Bathocuproinedisulfonic acid (BCS) (a high-affinity Cu(I) chelator), Ferrozine (Fe(II)), and BPS (Fe(II)). Growth responses were assessed via biomass measurements, while intracellular metal content was quantified using inductively coupled plasma mass spectrometry (ICP-MS). Interestingly, BCS treatment did not significantly inhibit growth or reduce copper content compared to control growth conditions, suggesting that S. parasitica may bypass extracellular copper chelation through alternative uptake pathways or internal copper reservoirs. To assess mitochondrial function, we measured Saprolegnia parasitica oxygen consumption using a Clark-type oxygen electrode under varying growth conditions. BCS-treated S. parasitica maintained respiration rates similar to the untreated controls, with a sustained contribution from the alternative oxidase (AOX) pathway, even under copper-limited conditions. These results indicate a possible shift in electron transport chain dynamics, allowing S. parasitica to maintain mitochondrial function when cytochrome c oxidase (CcO) is compromised by metal limitation.
Overall, this study provides novel insights into the adaptive mechanisms employed by S. parasitica to overcome metal deprivation. The ability to maintain respiration through AOX and resist copper chelation suggests that targeting metal homeostasis may require more nuanced strategies in the management of saprolegniasis. Results revealed that S. parasitica modulates growth and respiration in relation to environmental metal concentrations, with specific uptake mechanisms contributing to metal homeostasis. These findings highlight the importance of metal bioavailability in regulating the pathogen’s physiology and may inform approaches to limit its spread in aquaculture systems by manipulating environmental conditions or targeting metal acquisition pathways.Chemistry and Biochemistr
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
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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