1,720,958 research outputs found
ISSLS Prize Winner: Cost-effectiveness of two forms of circumferential lumbar fusion: A prospective randomized controlled trial
No full textStudy Design. Economic evaluation alongside a prospective, randomized controlled trial from a secondary care National Health Service (NHS) perspective. Objective. To determine the cost-effectiveness of titanium cages (TC) compared with femoral ring allografts (FRA) in circumferential lumbar spinal fusion. Summary of Background Data. A randomized controlled trial has shown the use of TC to be clinically inferior to the established practice of using FRA in circumferential lumbar fusion. Health economic evaluation is urgently needed to justify the continued use of TC, given that this treatment is less effective and, all things being equal, is assumed more costly than FRA. Methods. Eighty-three patients were randomly allocated to receive either the TC or FRA as part of a circumferential lumbar fusion between 1998 and 2002. NHS costs related to the surgery and revision surgery needed during the trial period were monitored and adjusted to the base year (2005–2006 Pounds Sterling). The Short Form-6D (SF-6D) was administered before surgery and at 6, 12 and 24 months in order to elicit patient utility and subsequently Quality-Adjusted Life Years (QALYs) for the trial period. Return to paid employment was also monitored. Bootstrapped mean differences in discounted costs and benefits were generated in order to explore cost-effectiveness. Results. A significant cost difference of £1950 (95% CI, £849 to £3145) in favor of FRA was found. Mean QALYs per patient over the 24-month trial period were 0.0522 (SD, 0.0326) in the TC group and 0.1914 (SD, 0.0398) in the FRA group, producing a significant difference of −0.1392 (95% CI, −0.2349 to −0.0436). With regard to employment, incremental productivity costs were estimated at £185,171 in favor of FRA. Conclusion. From an NHS perspective, the trial data show that TC is not cost-effective in circumferential lumbar fusion. The use of FRA was both cheaper and generated greater QALY gains. In addition, FRA patients reported a greater return to work rate
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
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
Axon stretch growth: towards functional repair of the spinal cord: a translational exercise
No full textBackground:
Injury to the spinal cord often visually presents as a local injury, damaging neurons that reside in the spinal cord, their projecting axons and supporting infrastructure such as oligodendrocytes. However, damage also occurs to ascending and descending axons that communicate with the brain. Fundamentally, repair of these injuries requires two distinct restorative approaches. The local injury will require stabilisation of the local environment, the rescue of injured neurons and support infrastructure, replacement of lost cells and restoration of intra-spinal communication. The latter ascending and descending axon injury will require proximal and distal axon reunification to restore supra-spinal communication with the brain.
This thesis presents the results of an early translational exercise that takes a non-linear approach to facilitate investigation into axon stretch growth (ASG) - an intrinsic mechanism that allows axons to adapt to body height and size throughout life. Pioneering research has shown that in-vitro exploitation of ASG has the potential to bridge significant gaps associated with injuries to long supra-spinal nerve tracts within the spinal cord.
Although translational science can be applied across the research spectrum, the traditional practice is to intervene once the research has matured. Here, the intervention occurs early, in an environment of limited funding within a progressive school of basic sciences. At the time of intervention, no infrastructure or experience in ASG research was evident within the faculties.
Translational Methods:
The absence of a robust in-vitro adult motor neuron culture was identified as a potential barrier in ASG translation. Collaborations in anatomy, neuroscience, and toxicology were formed. Three separate animal ethics applications were required. Publication of a protocol followed.
The infrastructure required to conduct necessary in-vitro investigations into ASG was determined. Multidisciplinary collaborations were formed with mechanical, electrical and electronics engineers. Design, engineering, and commissioning of the equipment followed.
The lack of a definitive translational animal model has been previously identified as a significant barrier to spinal cord injury research. Specifically, a suitable large animal model has yet to be clearly defined for ASG research. Collaborations with comparative anatomy, a large animal research centre, and a senior spinal surgeon progressed development of a sheep model. Separate multi-institutional animal ethics applications were also required.
Results:
A robust peer reviewed method was established to hydraulically extrude the spinal cord of adult Sprague-Dawley rats in under 60 seconds, and a serum free culture protocol simplified to maximise the yield of motor neurons and reduce culture costs. Adult motor neurons harvested and cultured using this protocol are capable of in-vitro survival for periods exceeding 21 days.
A decommissioned infant humidicrib was successfully converted into a portable temperature (32 – 39°C ± 0.1°C), and carbon dioxide controlled imaging incubator. Additional modifications incorporating umbilical support for multiple tailored bioreactors was also developed. A tailored ASG bioreactor was prototyped, tested, and commissioned. Axon stretch growth of motor neurons has been initiated in the bioreactor.
The literature review suggested that non-human primates were the optimal model for final translational confirmation. However, there was sufficient evidence to indicate that ungulates (i.e. sheep or pig) may be an alternative for ASG research. Relevant information on the sheep was collated, and basic investigation on their anatomy progressed.
Conclusion: Early applied translational science (as practised here) is strategic and cost effective, showing that the overall strategy facilitates research, while potentially identifying barriers that could delay progress or cause late translational failure. The introduction of an “off the shelf” early intervention funding model allocated to translational scientists should be considered as a mechanism to progress basic science investigations that are in conceptual stages of development.Thesis (Ph.D.) (Research by Publication) -- University of Adelaide, Adelaide Medical School, 201
To compare radio-stereometric analysis (RSA) and computed tomography (CT) for the assessment of lumbar spinal fusion in a sheep model.
Get PDFStudy design: A comparison of Radio-Stereometric Analysis (RSA) and Computed Tomography (CT) for the assessment spinal fusion in a large animal model. Introduction and Aims: Anterior Lumbar Interbody Fusion (ALIF) is a surgical procedure that is commonly performed for patients with chronic disabling low back pain that is unresponsive to conservative treatments. CT is a standard technique to assess the completeness of fusion but has a high radiation penalty to the patient. RSA is an alternative method to assess fusion with a much lower radiation exposure for the patient and is reported to have high accuracy. The study compares RSA to fine-cut CT scan using histology from necropsy specimens as the reference standard. Methods: Three non-adjacent ALIFs (L1-L2, L3-L4, and L5-L6) were carried out in 9 sheep. The sheep were divided into three groups of 3 sheep. The first group had RSA immediately post-op, 3 and 6 months after surgery. The second group had RSA immediately post-op, 3, 6 and 9 months after surgery. The third group had RSA immediately post-op, 3, 6, 9 and 12 months after surgery. All the animals were humanly killed immediately after having the last scheduled RSA. The lumbar spine was removed and invitro fine cut CT and histopathology were performed. The RSA was carried out by an experienced scientist to determine the number of fused levels. Post-mortem CT scans were performed and reviewed by up to three radiologists to assess the number of fused levels. Histology sections were taken throught the ALIF segments and reviewed by a senior research scientist with expertise in histology and a consultant pathologist. Results: Using histological assessment as the gold standard for assessing fusion, RSA demonstrated superior results (100% sensitivity and 66.7% specificity (PPV = 27.3%, NPV =100.0%) when compared to CT (66.7% sensitivity and 60.0% specificity (PPV = 16.7%, NPV = 93.8%). The assessment of the inter-rater reliability of the first CT scan of the two radiologists indicated no agreement (k = 0.07, p-value = 0.353). As indicated in the methods section, when a discrepancy occurred, a 3rd independent radiologist assessed the CT scans, with this review providing the final CT scan result. The Fleiss Kappa statistic indicated no agreement between the 1st and 3rd radiologist (k = 0.10, p-value = 0.333) on the occasions where the results of the 3rd radiologist were known (n=12 of the 27 results). The Fleiss Kappa statistic between the 2nd and 3rd radiologist also indicated no agreement (k = -0.13, p-value = 0.668). Significant inter-observer error was observed amongst radiologists using CT Scans for the assessment of fusion. Conclusion: Using histological assessment as the gold standard for the assessment of fusion in this animal model, RSA demonstrated higher sensitivity and specificity when compared to CT. Furthermore RSA has the advantage of much lower radiation exposure compared to fine cut CT. Further studies are required to see if RSA remains superior to CT scan for the assessment spinal fusion in the clinical setting.Thesis (M.S.) -- University of Adelaide, School of Medicine, 201
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
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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