1,721,029 research outputs found
Variations at the Calpain 1 gene locus in sporadic Creutzfeldt-Jakob disease
No full textHost genetic factors play a major role in the pathogenesis of transmissible spongiform
encephalopathies (TSEs). Polymorphisms in the prion protein gene (PRNP) modulate
susceptibility as well as phenotypic expression in both human and animal TSEs. Moreover,
familial forms of TSEs in humans are associated to specific PRNP mutations. Despite the strong
role of PRNP, additional genetic loci have been postulated since PRNP variability do not fully
explain disease susceptibility and incubation times. Genetic variability in Apo E, ADAM 10,
Doppel, LamR1, PLG, Hsp70 have been previously examined in Creutzfeldt-Jacob disease (CJD)
with inconclusive findings. Calpain, a cysteine protease, has been implicated in the pathogenesis
of different neurodegenerative including prion disease. We investigated whether variability in the
calpain gene may contribute to susceptibility or phenotypic expression of sporadic CJD. We
analyzed 5 single nucleotide polymorphisms within the calpain 1 gene as potential markers in
linkage disequilibrium with a functional polymorphism. 200 subjects with confirmed sporadic
CJD were studied. The polymorphisms located either in one “EF hand” domain or in the
proteolytic domain, were identified by dHPLC and/or sequencing analyses. 3 polymorphisms (rs
17880882, rs 11227153, rs 542380) did not show any significant difference in the genotype or
allele frequencies between CJD subjects and healthy controls, whereas the remaining two (rs
2277307 and rs 11227146), which were found to be in linkage disequilibrium, demonstrated a
different distribution in sporadic CJD carrying VV at codon 129. Our results seem to exclude a
major role of the calpain 1 gene in modulating susceptibility or phenotypic expression of sporadic
CJD. A potential subtype-specific role of calpain 1 gene variants should be investigated further in
larger sample groups
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
Protein misfolding cyclic amplification
No full textPrion diseases are caused by a conformational conversion of the cellular prion protein (PrPC) to a pathological conformer (PrPSc). The “prion-only” hypothesis suggests that PrPSc is the infectious agent that propagates the disease acting as a template for theconversion of PrPC. In 2001, we developed a novel in vitro technique, called Protein misfolding cyclic ampli fi cation (PMCA), which mimics this pathological process in an accelerated way. Thereby, minimal amount of PrPSc can be ampli fi ed to several millions fold, providing an important tool for diagnosis and investigation of prion biology, and the molecular mechanism of prion conversion. PMCA also offers a great platform for the study and ampli fi cation of the protein misfolding process associated with other neurodegenerative disorders, such as Alzheimer’s and Parkinson’s diseases
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
Protein Misfolding Cyclic Amplification
No full textPrion diseases are caused by a conformational conversion of the cellular prion protein (PrPC) to a pathological conformer (PrPSc). The “prion-only” hypothesis suggests that PrPSc is the infectious agent that propagates the disease acting as a template for the conversion of PrPC. In 2001, we developed a novel technique, called protein misfolding cyclic amplification (PMCA), which mimics in vitro this pathological process in an accelerated way. Thereby, a minimal amount of PrPSc can be amplified several million folds, providing an important tool for the diagnosis and investigation of prion biology, and the molecular mechanism of prion conversion. PMCA also offers a great platform for the study and amplification of the protein misfolding process associated with other neurodegenerative disorders, such as Alzheimer’s and Parkinson’s diseases. Here we are updating this previously published chapter to incorporate recent advances
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
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