1,721,006 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
Human Langerhans Cells with Pro-inflammatory Features Relocate within Psoriasis Lesions
No full textPsoriasis is a common skin disease that presents with well-demarcated patches of inflammation. Recurrent disease in fixed areas of the skin indicates a localized disease memory that is preserved in resolved lesions. In line with such concept, the involvement of tissue-resident immune cells in psoriasis pathology is increasingly appreciated. Langerhans cells (LCs) are perfectly placed to steer resident T cells and local tissue responses in psoriasis. Here, we present an overview of the current knowledge of LCs in human psoriasis, including findings that highlight pro-inflammatory features of LCs in psoriasis lesions. We also review the literature on conflicting data regarding LC localization and functionality in psoriasis. Our review highlights that further studies are needed to elucidate the molecular mechanisms that drive LCs functionality in inflammatory diseases
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
Dysregulation of receptor induced apoptosis during human leishmaniasis : a possible mechanism of skin ulceration
No full textLeishmaniasis is endemic in 88 countries and 12 million people per year have been estimated to be at risk of infection. The causative agent, the protozoan Leishmania, is spread by sand-flies and infects macrophages in the mammalian host. Leishmaniasis in humans form a spectrum of clinical presentations. In cutaneous leishmaniasis (CL) caused by L. major, the infection is localised in the skin and manifests as one or several ulcers that typically spontaneously heal within one year after infection, often leaving marked scarring. In visceral leishmaniasis (VL) caused by L. donovani, infected macrophages are found in liver, spleen, bone marrow and lymph-nodes and the infection leads to hepatosplenomegaly, wasting, fever and if not treated, to death. Systemic T-cell deficiency occurs early during VL and leads to uncontrolled parasite replication. In general, solid immunity upon healing occurs after resolved VL and CL.In this thesis, the hypothesis that alterations of death receptor-mediated apoptosis have an impact on the pathogenesis of human leishmaniasis has been explored. During VL, dysregulation of the Fas/FasL pathway was investigated, both at one site of infection, the spleen, and on circulating lymphocytes from the peripheral blood. In the case of CL the hypothesis was that increased death receptor-mediated apoptosis in the microenvironment surrounding infected macrophages may induce bystandard apoptosis of keratinocytes, leading to skin ulceration.Dysiregulation of the Fas/FasL pathway occured during human VL and CL. Levels of soluble Fas (sFas) and soluble Fas ligand (sFasL) were elevated in plasma of patients with active VL and individuals co-infected with VL-HIV-1 compared to healthy controls, and the levels of sFas and sFasL were normalized 6 months after successful treatment. During active VL, the expression of membrane bound Fas, and to a lower extent Fast., was up-regulated on spleen cells, where parasites multiply. In contrast, expression of Fas and Fast- were not altered on peripheral blood mononuclear cells (PBMC) during VL. Furthermore, in vitro infection of macrophages with L. donovani results in up-regulation of Fas expression on the surface of infected cells and increases the levels of sFasL in supernatants from infected cultures. During active CL caused by L. major, a disease mainly localised to the skin, the Fas and Fast- levels were not altered in serum or on PBMCs analysed ex vivo. However, when CL PBMCs were restimulated with L. major, Fas was up-regulated on effector T-cells and high levels of sFasL were detected in the supernatants as compared to control PBMCs.Keratinocyte apoptosis is altered during CL. Dysregulation of the Fas/FasL pathway in the microenvironment surrounding L. major infected macrophages under the skin was visualised in biopsies collected from CL patients. A substantial number of apoptotic keratinocytes were observed in the epidermis of morphologically active and healing CL skin samples. Fas expression was increased on the epidermis in active CL, whereas FasL expressing macrophages and T-cells were found in the subepidermal infiltrate during active disease. Supernatants from re-stimulated CL-PBMC cultures containing high levels of sFasL induced apoptosis in human keratinocyte cell line (HaCaT), and apoptosis could be inhibited in 213 supernatants by blocking Fas. A commercial apoptosis-specific microarray was used to assess alterations in keratinocyte RNAexpression during exposure to supernatants from L. major infected PBMCs. Fas and TRAIL mRNA and protein expression were significantly up-regulated compared to untreated keratinocytes. Supernatant induced apoptosis of keratinocytes was partly inhibited through blocking Fas or FasL, and more efficiently through inhibition of TRAIL by neutralising antibodies or soluble TRAIL-R. Furthermore, TRAIL expressing keratinocytes were detected in skin biopsies from CL cases.Blocking the Fas/FasL pathway in vivo may reduce ulceration during murine CL. In order to obtain the proof of the concept that Fas/FasL signalling is involved in keratinocyte-apoptosis leading to ulceration in the skin during CL, the Fas/FasL pathway was blocked in a murine model of CL by intraperitoneal treatment with Fast- neutralising antibodies (MFL-4). Skin inflammation, skin ulceration and ulcer size were followed weekly and compared to infected, untreated mice. Our results suggests that blocking Fas/FasL signalling during murine CL lead to less apoptotic keratinocytes and diminished ulceration. During treatment, the number of IFNgammaproducing CD8+CD3+ cells was increased at the site of infection when Fast- was neutralised which is suggestive of efficient parasite eradication. However, there was no reduction of parasite load at the site of infection or in draining lymph nodes and parasite replication was high upon discontinuation of anti-FasL treatment.Conclusion: The Fas/FasL pathway was shown to be dysregulated both in human VL and CL. A possible mechanism of ulcer formation during CL was proposed by apoptotic death of keratinocytes through enhanced Fast- and TRAIL signalling. This data was further strengthened in a treatment experiment in a murine model of CL, where blocking the Fas/FasL system reduced ulcer formation during L. major infection.List of scientific papersI. Eidsmo L, Wolday D, Berhe N, Sabri F, Satti I, El Hassan AM, Sundar S, Chiodi F, Akuffo H (2002). Alteration of Fas and Fas ligand expression during human visceral leishmaniasis. Clin Exp Immunol. 130(2): 307-13. https://doi.org/10.1046/j.1365-2249.2002.01976.x II. Eidsmo L, Nylen S, Khamesipour A, Hedblad MA, Chiodi F, Akuffo H (2005). The contribution of the Fas/FasL apoptotic pathway in ulcer formation during Leishmania major-induced cutaneous Leishmaniasis. Am J Pathol. 166(4): 1099-108. https://doi.org/10.1016/S0002-9440(10)62330-9 III. Eidsmo L, Fluur C, Eriksson Ygberg S, DeMilito A, Rethi B, Akuffo H, Chiodi F (2006). FasL and TRAIL induced epidermal apoptosis and skin ulceration upon exposure to Leishmania major infection. [Submitted]IV. Eidsmo L, Nylen Spoormaker S, Lieke T, Peters N, Yagita H, Sacks D, Akuffo H, Chiodi F (2006). The effect of neutralisation of FasL on skin ulceration in murine models of cutaneous leishmaniasis. [Manuscript]</p
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
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