1,720,957 research outputs found
Feasibility of flat panel detector computed tomography for position assessment of external ventricular drainage
No full textBackground and purpose: New angiographic devices with flat panel detectors allow cross-sectional imaging within the angiographic suite. In patients receiving external ventricular drainage (EVD) to manage hydrocephalus following subarachnoid haemorrhage (SAH), these may help evaluating the position of an EVD without moving the patient to a conventional computed tomography (CT) scanner. It could facilitate patients' management in a life-threatening status. This study therefore compares conventional CT with post-interventional flat panel detector angiographic CT (FDCT) referring to the determinability of an accurate EVD position. Material and methods: Twenty patients with SAH received FDCT and conventional CT for primary assessment after EVD insertion. Three single-blinded raters compared both modalities and evaluated the image sufficiency for determining the EVD position, EVD tip, intracranial course and whether a contorted drainage tube could be detected. Results: FDCT was sufficient to detect a correct EVD position in 82.5% of the cases vs. 100% in conventional CT Regarding the EVD tip, FDCT delivered at least 'good' results in 82.5% vs. 95% in conventional CT data. Determining the EVD intracranial course, FDCT provided at least 'good' data in 92.5% vs. 100% in conventional CT For detecting tube contortion, FDCT provided at least 'good' results in 70% vs. 98% in conventional CT. Conclusions: FDCT is a promising method to determine the correct position of an EVD in patients with SAH. Following a neuroradiological intervention, it facilitates the patients' management and renders additional transfers to conventional CT unnecessary in the majority of cases
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
Occlusion of surgical opening of the ventricular system with fibrinogen-coated collagen fleece: a case collection study
No full textImplantation of 1,3-bis (2-chloroethyl)-1-nitrosourea (BCNU) wafer for malignant glioma is not recommended in the case of surgical opening of the ventricular system during microsurgical tumor resection because the wafer material may dislocate from the resection cavity into the ventricular system and cause obstructive hydrocephalus. TachoSil is an adhesive collagen fleece used in different surgical disciplines that provides an air- and liquid-tight seal closing communications between the ventricular system and the resection cavity after tumor removal. Occlusion of ventricular defects with TachoSil after microsurgical glioma resection was performed in two patients with newly diagnosed and seven patients with recurrent malignant glioma prior to BCNU wafer implantation into the resection cavity. Early postoperative cranial computed tomography (CCT)/MRI and follow-up MRI at 3 months' intervals were performed with a median follow-up of 10.4 months. The collagen fleece was identified as a linear structure hypodense/hypointense to white matter on postoperative CT/MRI separating the resection cavity from the ventricular lumen in all cases. In no case did early CCT/MRI or follow-up MRI reveal wafer material within the ventricular system. In no case did signs of obstructive hydrocephalus occur. Sealing of the ventricular system using a fibrinogen-coated collagen fleece effectively separates the resection cavity from the ventricular system and allows implantation of BCNU wafers into the resection cavity. No morphological evidence for wafer material dislocation into the ventricular system or obstruction of CSF pathways was found in nine patients who received 41 follow-up MRI over 10.4 months of follow-up
Magnetic resonance imaging study of the in vivo position of the extraglottic airway devices i-gel and LMA-Supreme in anaesthetized human volunteers
No full textExact information on the anatomical in situ position of extraglottic airway (EGA) devices is lacking. We used magnetic resonance imaging (MRI) to visualize the positions of the i-gel and the LMA-Supreme (LMA-S) relative to skeletal and soft-tissue structures. Twelve volunteers participated in this randomized, prospective, cross-over study. Native MRI scans were performed before induction of anaesthesia. Anaesthesia was induced, and the two EGAs were inserted in a randomized sequence. Their positions were assessed functionally, optically by fibrescope, and with MRI scans of the head and neck. The LMA-S protruded deeper into the upper oesophageal sphincter than the i-gel (P0.001). Both devices reduced the area of the glottic aperture (P0.001), and the LMA-S had the largest effect (P0.049). The i-gel significantly compressed the tongue (P0.001). Both devices displaced the hyoid bone ventrally (P0.001); the i-gel to a greater degree (P0.029). The fibreoptically determined position of the bowl of the devices was identical. The LMA-S and i-gel differ significantly with regard to in situ position and spatial relationship with adjacent structures assessed by MRI, despite similar clinical and fibreoptical findings. This could be relevant with regard to risk of aspiration, glottic narrowing, and airway resistance and soft-tissue morbidity
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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