1,720,978 research outputs found
Heparin and dialysis: reasons to make a change?
No full textThe availability of heparin was undoubtedly one of the main factors contributing to the widespread use of clinical dialysis: although lipolytic activity, osteoporosis and thrombocytopenia were described, clinical advantages remained unrivalled until today. Nevertheless, several effects attributable to heparin are less widely recognized, though theoretically noteworthy. Heparin has immunosuppressive properties, interfering with both humoral and cell-mediated immunity [1–2]: these actions should be probably taken in to account since dialysis patients are prone to infections and receive an average of 500000–1 million units/year of heparin. Heparin is able to split the activin–follistatin complex, allowing activin to stimulate smooth muscle cells of vessel wall to proliferate [3]; the risk of systemic atherosclerosis could therefore be increased [4]. In addition, by the same mechanism heparin could favour the process of intimal hyperplasia leading to stenosis, usually observed just at the venous end of vascular access, the site where dialysis-administered heparin concentration is higher than in any other site of the vessel system. Finally, the source of heparin could be of some concern after description of the variant of Creutzfeld-Jacob encephalopathy (vCJ) as a prion disease transmitted by cows suffering from BSE. Of interest, it was reported that there was an increased risk of sporadic CJD for patients undergoing surgery, unfortunately without explanation of the mechanism(s) involved [5]. Intra-operative or prophylactic post-operative heparin administration could not be ruled out. Since heparin can be extracted from beef or pork offal, beef-derived heparin should be re-evaluated for medical use and dialysis patients suffering from encephalopathies should be screened for vCJ. Apart from the more specific mode of action [6], recombinant hirudin should be considered if the safe origin of heparin cannot be certified
Which is the preferred vascular access in diabetic patients? A view from Europe
No full textNo abstract available
Quality of water, dialysate and infusate
No full textGreat improvements in water treatment technology and the spread of ultrafiltration for cold sterilization have been the basic support for the development and diffusion of on-line dialysis treatments. Some 20 years ago, nephrologists recognized that the official standards for dialysis fluids were insufficient with respect to these new treatment modalities, and ultrapure water (bacteria <0.1 CFU/ml; endotoxin <0.03 EU/ml) was proposed as a reference. Today, ultrapure water is included in most guidelines and recommended standards, but there remains a need for harmonization between standards. To achieve and ensure these levels of purity, technology must be supported by commitment of resources to an active quality assurance programme with adequate maintenance, monitoring, cleaning, sanitizing and problem analysis procedures
Urea determination in dialysis, based on a differential pH technique
No full textThe application of a new technique, based on differential measurements of pH, to determine urea concentration in patients of a dialysis center, is reported. Urea in plasma, whole blood or dialysis fluids is measured by an enzymatic reaction, with urease; the procedure, requiring 10 microL of sample, is simple, fast and correlates well with a reference spectrophotometric method, in the 0-300 mg/dL concentration range, according to the equation y = 1.0291 X -0.0777; r = 0.9991; n = 73
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
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
Functional and metabolic effects of everolimus-based immunosuppression in dual kidney transplantation
No full textCongresso ESO
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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