1,720,980 research outputs found
Extracorporeal Shock Waves Stimulate Osteoblast Activities
No full textThe extracorporeal shock wave therapy (ESWT) is an extensively applied treatment for musculoskeletal disorders because it promotes bone repair. The aim of this study was to evaluate the direct effect of ESWT on murine osteoblasts to clarify the cellular mechanism that leads to the induction of osteogenesis. Osteoblasts in culture flasks were treated with ESWT pulses (500 impulses of 0.05 mJ/mm(2)) generated by an electromagnetic device. Using western blot analysis 3 h after ESWT, an increased expression of Bax was found, indicating a fast pro-apoptotic effect of treatment on some of the osteoblasts. Activation of the cyclin E2/CDK2 is the complex that regulates the G1-S transition and is essential for cell proliferation. It was evident 24 to 72 h after treatment, indicating a proliferative stimulus. A decreased expression of osteoprotegerin (OPG) and receptor activator NF kappa B ligand (RANKL) 24 and 48 h after ESW, followed by a later increase of OPG, paired with a much smaller increase of RANKL, was evident by real-time polymerase chain reaction (PCR). The decreased RANKL/OPG ratio suggests inhibition of osteoclastogenesis. We can conclude that ESWT induces bone repair through the proliferation and differentiation of osteoblasts and the reduction of their secretion of pro-osteoclastogenic factors. (E-mail: [email protected]) (C) 2009 World Federation for Ultrasound in Medicine & Biology
Alumina-on-alumina total hip replacement for femoral neck fracture in healthy patients
Full text linkAbstract Background Total hip replacement is considered the best option for treatment of displaced intracapsular fractures of the femoral neck (FFN). The size of the femoral head is an important factor that influences the outcome of a total hip arthroplasty (THA): implants with a 28 mm femoral head are more prone to dislocate than implants with a 32 mm head. Obviously, a large head coupled to a polyethylene inlay can lead to more wear, osteolysis and failure of the implant. Ceramic induces less friction and minimal wear even with larger heads. Methods A total of 35 THAs were performed for displaced intracapsular FFN, using a 32 mm alumina-alumina coupling. Results At a mean follow-up of 80 months, 33 have been clinically and radiologically reviewed. None of the implants needed revision for any reason, none of the cups were considered to have failed, no dislocations nor breakage of the ceramic components were recorded. One anatomic cementless stem was radiologically loose. Conclusions On the basis of our experience, we suggest that ceramic-on-ceramic coupling offers minimal friction and wear even with large heads.</p
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
Roentgen stereophotogrammetric analysis: an effective tool to predict implant survival after an all-poly unicompartmental knee arthroplasty—a 10 year follow-up study
No full textThe main purpose of the present study was to determine long-term implant fixation of 15 unicompartmental knee arthroplasty (UKAs) with an all-poly tibial component using Roentgen stereophotogrammetric analysis (RSA) at a mean 10-year follow-up. The secondary purpose was to investigate whether the progressive loss of implant's fixation correlates with a reduction in Knee society score (KSS).
METHODS:
Fifteen non-consecutive patients with primary knee osteoarthritis received a UKA with an all-poly tibial component were assessed using KSS scores pre-operatively and post-operatively and RSA on day 2 after surgery, then at 3, 6, and 12 months and yearly thereafter. The mean last follow-up was 10 years.
RESULTS:
An increase in maximum total point motion (MTPM) values from 6 months to 1 year post-operatively was found respect to post-operative reference. Implants' displacement values were always 0.2 mm in revised UKAs. A linear and negative correlation with statistical significance was found between MTPM and both clinical and functional KSS scores (p < 0.001).
CONCLUSION:
Also in a long-term follow-up evaluation, RSA is an effective tool to predict functional results after an all-poly UKA providing also a relevant predictive value at 1 year follow-up, and this can be very useful for both patients and surgeons
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