1,721,443 research outputs found
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
Το σύστημα RANK, RANK-L και οστεοπροτεγερίνης ως βιοδείκτης
No full textΤο σύστημα του συνδέτη του ενεργοποιητή του υποδοχέα του πυρηνικού παράγοντα κΒ (RANK-L), του ενεργοποιητή του υποδοχέα του πυρηνικού παράγοντα κΒ (RANK) και της οστεοπροτεγερίνης (OPG) αναγνωρίστηκε στα τέλη της δεκαετίας του 1990, στην προσπάθεια ταυτοποίησης των παραγόντων που ρυθμίζουν την οστεοκλαστογένεση. Σήμερα, ο ρόλος του συστήματος στην οστική ανακατασκευή έχει περιγραφεί αναλυτικά, όπως και η συμμετοχή του στην παθοφυσιολογία των νοσημάτων των οστών. Η χρήση του συστήματος RANK, RANK-L και οστεοπροτεγερίνης ως βιοδείκτης έχει μελετηθεί σε πολλά μεταβολικά νοσήματα των οστών και των δοντιών, καθώς και σε πρωτοπαθή και μεταστατικά νεοπλάσματα του ερειστικού συστήματος. Η συσχέτιση των μεταβολών του συστήματος RANK/RANK-L/OPG με την αιτιοπαθογένεια νοσημάτων του καρδιαγγειακού συστήματος, αλλά και ρευματολογικών και αυτοάνοσων ασθενειών έχει οδηγήσει στην πραγματοποίηση ερευνών που έχουν ως στόχο την χρήση των μελών του συστήματος RANK, RANK-L και οστεοπροτεγερίνης ως βιοδείκτες, μεμονωμένα ή συνδυαστικά, για τη διάγνωση, την πρόγνωση και τη θεραπεία παθήσεων που δεν σχετίζονται με τα οστά.The system that is composed by the receptor activator of nuclear factor (NF)-kΒ-ligand (RANK-L), the receptor activator of nuclear factor kB (RANK) and the receptor osteoprotegerin (OPG), was identified in the late 1990s, while trying to isolate factors that regulate osteoclastogenesis. Today, the role of the system in bone remodeling has been described in detail and its involvement in the pathophysiology of bone diseases is well analysed. The RANK, RANK-L and osteoprotegerin system has been used as a biomarker in many metabolic diseases of the bones and of the teeth, and in primary and metastatic tumors of the skeletal system. The correlation of the changes of the RANK, RANK-L and OPG axis with the etiology of many conditions of the cardiovascular system, as well as rheumatic and autoimmune diseases, has led to many researches that aimed at the use of the RANK, RANK-L and osteoprotegerin system as a biomarker for the diagnosis, the prognosis and the treatment of non-bone related disorders
Osteoprotegerin (OPG)/RANK-L System in Juvenile Idiopathic Arthritis: Is There a Potential Modulating Role for OPG/RANK-L in Bone Injury?
No full textAbstract OBJECTIVE: To evaluate serum levels of osteoprotegerin (OPG) and receptor activator of nuclear factor kB-ligand (RANK-L) in patients with juvenile idiopathic arthritis (JIA); to correlate these values with disease activity variables, radiological bone damage, and bone mass; and to correlate OPG gene polymorphisms with bone mass. METHODS: Eighty-four patients (66 girls and 18 boys) with JIA and 40 sex and age-matched controls were enrolled. Serum OPG and RANK-L were measured using an enzyme-linked immunosorbent assay. OPG genotyping was performed by polymerase chain reaction. RESULTS: Patients with JIA had significantly higher levels of serum OPG than controls (p = 0.001) and lower levels of RANK-L in comparison with controls (p = 0.0003). The OPG/RANK-L ratio in patients was higher than in controls (p = 0.004). No significant correlations were found between disease duration, erythrocyte sedimentation rate, and C-reactive protein values with either OPG or RANK-L serum levels. A significant difference in serum OPG levels (but not in RANK-L) was found between patients with and without erosions (p = 0.008). No correlation was found between OPG and RANK-L levels and bone mass (DXA Z scores). A higher prevalence of OPG CC genotype was found in both patients (65.4%) and controls (82.5%) (p = 0.006). Subjects with CC genotype had a higher lumbar spine bone mineral density (LS-BMD). CONCLUSION: We evaluated for the first time levels of OPG and RANK-L in children with JIA. The higher OPG/RANK-L ratio in JIA might be the result of a compensatory production of OPG. The presence of the T allele of the OPG gene appears to be associated with low BMD
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
OPG, RANK-L bone metabolism and BMD in patients on peritoneal dialysis and hemodialysis
No full textOBJECTIVES: Bone turnover is regulated locally by osteoprotegerin (OPG) and receptor activator of NFkappaB ligand (RANK-L); it is not known how the circulating concentrations of these cytokines reflect renal osteodystrophy. METHODS: We measured serum OPG, RANK-L, parathyroid hormone (iPTH), collagen C-terminal cross-linked telopeptide (betaCrossLaps), and bone densitometry (BMD) in 79 patients with end-stage renal disease (ESRF) undergoing dialysis. A hand X-ray of these patients was also analyzed. Controls were 65 healthy subjects. RESULTS: ESRF patients had high OPG and RANK-L levels; RANK-L was higher in hemodialysis than in peritoneal dialysis. OPG and RANK-L did not depend on iPTH. The bone markers were significantly increased and correlated with serum iPTH, but not with OPG or RANK-L; neither OPG nor RANK-L correlated significantly with BMD. OPG was significantly higher in patients with acro-osteolysis. CONCLUSIONS: OPG and RANK-L serum concentrations do not strongly reflect bone status in ESRF. However, OPG was significantly higher in patients with acro-osteolysis.Journal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe
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
HDAC7 KO osteoclasts show increased sensitivity to RANK-L cytokine
No full textUniversity of Minnesota M.S. thesis. June 2019. Major: Dentistry. Advisors: Kim Mansky, John Beyer. 1 computer file (PDF); v, 23 pages.Bone homeostasis is a balance between osteoclast-mediated bone resorption and osteoblast-mediated bone formation. Two cytokines, M-CSF and RANK-L are known to be necessary in osteoclast differentiation. Histone deacetylases (HDACs) are key regulators of gene expression, and recently have been shown to be important modulators in osteoclast differentiation. In previous research, HDAC7 has been shown to be a negative regulator of osteoclastogenesis. Osteoclasts from HDAC7 KO mice are increased in size and number. This study aims to test the hypothesis that osteoclasts from HDAC7 KO mice are hypersensitive to M-CSF and/or RANK-L. Results from my study demonstrate enhanced osteoclast differentiation in size and number of osteoclasts and resorption under varying M-CSF and RANK-L concentrations in HDAC7 KO compared to wild type osteoclasts. Mechanistically the hypersensitivity may be explained because HDAC7 KO osteoclasts had increased C-fms and RANK expression compared to wild type osteoclasts. Further research is necessary to determine if the hypersensitivity is due to increased gene expression by transcription factors MITF and PU.1.Newton, Brieanna Lise. (2019). HDAC7 KO osteoclasts show increased sensitivity to RANK-L cytokine. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/211307
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