1,720,997 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
Cytokeratin-19, a predictive marker and an early determinant of progenitor-derived hepatocellular carcinoma
No full textBackground: Human hepatocellular carcinoma (HCC) is a heterogeneous disease of distinct clinical subgroups. A principal source of tumor heterogeneity may be cell type of origin which in liver includes hepatocyte and/or adult stem/progenitor cells. Objective: To address this issue, we investigated the molecular mechanisms underlying the fate of the enzyme-altered preneoplastic lesions in the resistant hepatocyte (RH) model. Methods: Sixty samples classified as focal lesions, adenoma, early and advanced HCCs were micro-dissected after morphological and immunohistochemical evaluation and subjected to global gene expression profiling. Results: The analysis of progression of the persistent GSTP+ focal lesions to fully developed HCC showed that about 50% of persistent nodules and all HCCs expressed CK19 whereas 14% of remodeling nodules were CK19+. Unsupervised hierarchical clustering of the expression profiles also grouped the samples according to CK19 expression. Further, supervised analysis using the differentially expressed genes in each cluster combined with the gene connectivity tools identified 1308 unique genes and a predominance of the AP-1/JUN network in the CK19+ lesions. In contrast, the CK19-negative cluster exhibited only limited molecular changes (156 differentially expressed genes vs. normal liver) consistent with remodeling towards differentiated phenotype. Finally, comparative functional genomics revealed a stringent clustering of CK19+ early lesions and advanced HCCs with human HCCs characterized by poor prognosis. Furthermore, the CK19 associated gene expression signature accurately predicted the patient survival (P<0.009) and tumor recurrence (P<0.006). Conclusion: Our data establish CK19 as a prognostic marker of early neoplastic lesions and strongly suggest the progenitor derivation of HCC in the rat RH model. The capacity of the CK19 associated gene signature to stratify HCC patients according to clinical prognosis indicates the usefulness of the RH model for studies of stem/progenitor-derived HCC
Lack of on-going adaptations in the soleus muscle activity during walking in patients affected by large-fiber neuropathy.
No full textThe aim of this study
was to investigate the contribution of feedback from large-diameter
sensory fibers to the adaptation of soleus muscle activity after small
ankle trajectory modifications during human walking. Small-amplitude
and slow-velocity ankle dorsiflexion enhancements and reductions
were applied during the stance phase of the gait cycle to mimic
the normal variability of the ankle trajectory during walking. Patients
with demyelination of large sensory fibers (Charcot-Marie-Tooth type
1A and antibodies to myelin-associated glycoprotein neuropathy) and
age-matched controls participated in this study. The patients had
absent light-touch sense in the toes and feet and absent quadriceps and
Achilles tendon reflexes, indicating functional loss of large sensory
fibers. Moreover, their soleus stretch reflex response consisted of a
single electromyographic (EMG) burst with delayed onset and longer
duration (P 0.01) than the short- and medium-latency reflex
responses observed in healthy subjects. In healthy subjects, the soleus
EMG gradually increased or decreased when the ankle dorsiflexion
was, respectively, enhanced or reduced. In the patients, the soleus
EMG increased during the dorsiflexion enhancements; however, the
velocity sensitivity of this response was decreased compared with the
healthy volunteers. When the dorsiflexion was reduced, the soleus
EMG was unchanged. These results indicate that the enhancement of
the soleus EMG is mainly sensitive to feedback from primary and
secondary muscle spindle afferents and that the reduction may be
mediated by feedback from the group Ib pathways. This study provides
evidence for the role of sensory feedback in the continuous
adaptation of the soleus activity during the stance phase of human
walking
Progenitor-derived hepatocellular carcinoma model in the rat
No full textHuman hepatocellular carcinoma (HCC) is a heterogeneous disease of distinct clinical subgroups. A principal source of tumor heterogeneity may be cell type of origin, which in liver includes hepatocyte or adult stem/progenitor cells. To address this issue, we investigated the molecular mechanisms underlying the fate of the enzyme-altered preneoplastic lesions in the resistant hepatocyte (RH) model. Sixty samples classified as focal lesions, adenoma, and early and advanced HCCs were microdissected after morphological and immunohistochemical evaluation and subjected to global gene expression profiling. The analysis of progression of the persistent glutathione S-transferase (GSTP)(+) focal lesions to fully developed HCC showed that approximately 50% of persistent nodules and all HCCs expressed cytokeratin 19 (CK19), whereas 14% of remodeling nodules were CK19(+). Unsupervised hierarchical clustering of the expression profiles also grouped the samples according to CK19 expression. Furthermore, supervised analysis using the differentially expressed genes in each cluster combined with gene connectivity tools identified 1308 unique genes and a predominance of the AP-1/JUN network in the CK19(+) lesions. In contrast, the CK19-negative cluster exhibited only limited molecular changes (156 differentially expressed genes versus normal liver) consistent with remodeling toward differentiated phenotype. Finally, comparative functional genomics showed a stringent clustering of CK19(+) early lesions and advanced HCCs with human HCCs characterized by poor prognosis. Furthermore, the CK19-associated gene expression signature accurately predicted patient survival (P < 0.009) and tumor recurrence (P < 0.006). Conclusion: Our data establish CK19 as a prognostic marker of early neoplastic lesions and strongly suggest the progenitor derivation of HCC in the rat RH model. The capacity of CK19-associated gene signatures to stratify HCC patients according to clinical prognosis indicates the usefulness of the RH model for studies of stem/progenitor-derived HCC
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
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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