1,720,986 research outputs found
Novel, digital, chest drainage system in cardiac surgery
No full textA new, self-contained, digital, continuous pump-driven chest drainage system is compared in a randomized control trial to a traditional wall-suction system in cardiac surgery
Histologic Assessment of Drug-Eluting Grafts Related to Implantation Site
No full textDrug-eluting vascular prostheses represent a new direction in vascular surgery to reduce
early thrombosis and late intimal hyperplasia for small calibre grafts. Subcutaneous implantation in
rats is a rapid and cost-effective screening model to assess the drug-elution effect and could, to some
extent, be useful to forecast results for vascular prostheses. We compared biological and histological
responses to scaffolds in different implantation sites. Polycaprolactone (PCL), paclitaxel-loaded
PCL (PCL-PTX) and dexamethasone-loaded PCL (PCL-DXM) electrospun scaffolds were implanted
subcutaneously and in an infrarenal abdominal aortic model in rats for up to 12 weeks. At the
conclusion of the study, a histological analysis was performed. Cellular graft invasion revealed
differences in the progression of cellular infiltration between PCL-PTX and PCL/PCL-DXM groups in
both models. Cell infiltration increased over time in the aortic model compared to the subcutaneous
model for all groups. Cell counting revealed major differences in fibroblast, macrophage and
giant cell graft colonisation in all groups and models over time. Macrophages and giant cells
increased in the PCL aortic model; whereas in the subcutaneous model these cell types increased
only after three weeks or even decreased in the drug-eluting PCL groups. Other major findings were
observed only in the aortic replacement such as extracellular matrix deposition and neo-angiogenesis.
The subcutaneous implant model can be used for screening, especially when drug-eluting effects are
studied. However, major histological differences were observed in cell type reaction and depth of
cell penetration compared to the aortic model. Our results demonstrate that the implantation site is
a critical determinant of the biological response
Failed coronary artery bypass anastomosis detected by intraoperative coronary flow measurement
Full text linkObjectives: To assess intraoperative flow of arterial and venous coronary grafts after myocardial revascularization which may allow early detection of low flow situations, especially during minimally invasive coronary bypass surgery (MIDCAB), and lead to immediate correction of technical problems. Methods: In two patients with severe and diffuse multi-vessel disease the left internal mammary artery (IMA) was connected to the left anterior descending artery (LAD). During reperfusion, the flow was measured in the IMA and vein grafts using a transit time flow meter. Results: In both cases the IMA showed only a systolic pendulating flow curve with a mean flow of 0–1 ml/min and a high resistance. Manual IMA assessment revealed an adequate pulsation. Both distal IMA anastomoses were re-explored on cardiopulmonary bypass yielding an initial flow of 7 and 14 ml/min, respectively. After treatment with papaverine/adenosine the IMA flow increased from 7 to 26 ml/min (coronary flow reserve (CFR)=3.7) and from 14 to 46 ml/min (CFR=3.3), respectively. Conclusion: Intraoperative flow assessment of IMA and venous bypass grafts can be recommended to monitor flow; especially during MIDCAB procedures
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
Vascular adaptation of the internal thoracic artery graft early and late after bypass surgery
No full textFlow mismatch between the supplying artery and the myocardial perfusion region has been observed in patients with internal thoracic artery grafts. Thus coronary flow changes of arterial (internal thoracic artery grafts) and saphenous (saphenous vein grafts) bypass grafts were studied early and late after coronary artery bypass grafting
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
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