63 research outputs found

    Acromioplasty during repair of rotator cuff tears removes only half of the impinging acromial bone.

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    To date, there is no consensus on when and how to perform acromioplasty during rotator cuff repair (RCR). We aimed to determine the volume of impinging bone removed during acromioplasty and whether it influences postoperative range of motion (ROM) and clinical scores after RCR. Preoperative and postoperative computed tomography scans of 57 shoulders that underwent RCR were used to reconstruct scapula models to simulate volumes of impinging acromial bone preoperatively and then compare them to the volumes of bone resected postoperatively to calculate the proportions of desired (ideal) vs. unnecessary (excess) resections. All patients were evaluated preoperatively and at 6 months to assess ROM and functional scores. The volume of impinging bone identified was 3.5 ± 2.3 cm <sup>3</sup> , of which 1.6 ± 1.2 cm <sup>3</sup> (50% ± 27%) was removed during acromioplasty. The volume of impinging bone identified was not correlated with preoperative critical shoulder angle (r = 0.025, P = .853), nor with glenoid inclination (r = -0.024, P = .857). The volume of bone removed was 3.7 ± 2.2 cm <sup>3</sup> , of which 2.1 ± 1.6 cm <sup>3</sup> (53% ± 24%) were unnecessary resections. Multivariable analyses revealed that more extensive removal of impinging bone significantly improved internal rotation with the arm at 90° of abduction (beta, 27.5, P = .048) but did not affect other shoulder movements or clinical scores. Acromioplasty removed only 50% of the estimated volume of impinging acromial bone. More extensive removal of impinging bone significantly improved internal rotation with the arm at 90° of abduction

    Community Structure Characterization

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    This entry discusses the problem of describing some communities identified in a complex network of interest, in a way allowing to interpret them. We suppose the community structure has already been detected through one of the many methods proposed in the literature. The question is then to know how to extract valuable information from this first result, in order to allow human interpretation. This requires subsequent processing, which we describe in the rest of this entry

    Social Interactions vs Revisions, What is important for Promotion in Wikipedia?

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    In epistemic community, people are said to be selected on their knowledge contribution to the project (articles, codes, etc.) However, the socialization process is an important factor for inclusion, sustainability as a contributor, and promotion. Finally, what does matter to be promoted? being a good contributor? being a good animator? knowing the boss? We explore this question looking at the process of election for administrator in the English Wikipedia community. We modeled the candidates according to their revisions and/or social attributes. These attributes are used to construct a predictive model of promotion success, based on the candidates's past behavior, computed thanks to a random forest algorithm. Our model combining knowledge contribution variables and social networking variables successfully explain 78% of the results which is better than the former models. It also helps to refine the criterion for election. If the number of knowledge contributions is the most important element, social interactions come close second to explain the election. But being connected with the future peers (the admins) can make the difference between success and failure, making this epistemic community a very social community too

    Is sling immobilization necessary after open Latarjet surgery for anterior shoulder instability? A randomized control trial.

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    There is a current lack of knowledge regarding optimal rehabilitation and duration of sling immobilization after an open Latarjet procedure. A shift towards immediate self-rehabilitation protocols in shoulder surgery is observed to avoid postoperative stiffness and fasten return to sport. Avoiding sling immobilization could further simplify rehabilitation and provide an even faster return to activities of daily living and enhance patient satisfaction. This study is a single-center, randomized control trial. Sixty-eight patients will be instructed with the same standardized immediate postoperative self-rehabilitation protocol. Patients will be allocated 1:1 between a sling immobilization group for the first three postoperative weeks and no sling group without postoperative immobilization. The primary endpoint will be functional outcome at 6 months postoperative evaluated by the disease-specific Rowe score. Secondary endpoints will include baseline, 1.5-, 6-, and 12-month single assessment numeric evaluation (SANE) of instability score and visual analog pain scale (VAS). At the 6-month time point, graft bony union and position will be assessed by computed tomography. Motion capture technology will evaluate the baseline and 6-month postoperative range of motion. Finally, time to return to work and sport during the first postoperative year, along with patient satisfaction at one postoperative year, will also be recorded. This study will allow further insights into the optimal rehabilitation protocol after open Latarjet surgery and enhance patient care by helping identify rehabilitation and coracoid graft-related factors influencing functional outcomes, bony union, range of motion, and patient satisfaction. The protocol was approved by the ethical committee board (CCER 2019-02,469) in April 2020 and by ClinicalTrials.gov (Identifier: NCT04479397 ) in July 2020

    Étude de la structure électronique de carbones prégraphitiques

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    On a étudié l’effet Hall, la magnétorésistance, la résistivité, la susceptibilité magnétique, et la résonance paramagnétique électronique d’un coke de brai, ainsi que l’évolution de ces propriétés au cours de la graphitisation. Les résultats sont généralement en bone accord avec ceux d’études antérieures menées sur des carbones de ce type. Certaines convergences qualitatives permettent de distinguer deux domaines « critiques » de températures de traitement. Le nombre des porteurs de charges libres déterminé par la résonance paramagnétique concorde remarquablement avec celui que l’on obtient à partir du diamagnétisme à basse température

    Potentiation effect of vasopressin on melatonin secretion as determined by trans_pineal microdialysis in the Rat

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    The mammalian pineal gland is known to receive a noradrenergic innervation originating from the superior cervical ganglion which corresponds to the primary regulatory input for melatonin synthesis. However, many peptidergic fibers containing peptides such as vasopressin and oxytocin have also been found in the rat pineal gland. The present study was performed to investigate the possible role of vasopressin and oxytocin on melatonin secretion in vivo. Therefore, both neuropeptides were delivered for 2 h through a trans-pineal microdialysis probe directly into the gland at different times during the nocturnal phase of the light:dark cycle. At the same time pineal dialysates were collected continuously. Melatonin concentrations were measured by radioimmunoassay. Melatonin synthesis potentiation was achieved when vasopressin was infused locally in the pineal, during the onset of nocturnal melatonin secretion. In order to assess the possible role of a physiological increase of endogenous circulating vasopressin on pineal metabolism, melatonin synthesis was recorded in the same animals before and after a prolonged dehydration period. Night time melatonin concentration was increased after the water deprivation vs control conditions. Contrary to that, oxytocin seems not to affect pineal metabolism in the rat since no significant change was observed on melatonin secretion in response to a local oxytocin infusion. These results show that vasopressin can modulate melatonin synthesis in the rat pineal whereas no effect was obtained with oxytocin, at least under the present experimental condition

    Guided versus freehand acromioplasty during rotator cuff repair. A randomized prospective study.

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    There is no consensus on how to perform acromioplasty, particularly regarding the level and extent of bone resection, which depend on scapular and humeral morphologies. We aimed to determine whether computer-assisted acromioplasty planning helps surgeons remove impinging bone, reduce unnecessary resections, and improve short-term outcomes of rotator cuff tears (RCR). We randomized 64 patients undergoing RCR of full-thickness supraspinatus tears into two groups: 'guided acromioplasty' (GA) and 'freehand acromioplasty' (FA). The pre- and post-operative scapula models were reconstructed using computed-tomography scans to quantify impinging bone removal, unnecessary bone resections, and identify zones of acromial bone removal. All patients were evaluated preoperatively and at 6 months to assess their range of motion (ROM), functional scores and tendon integrity using ultrasound. The two groups did not differ in demographics, clinical or morphologic characteristics. Compared to FA, GA tended to lower impinging bone removal (55±26% vs. 43±27%, p=0.087) and to increase unnecessary resection of the total bone removed (49±22% vs. 57±27%, p=0.248). GA resulted in significant anterior under-resection, while FA resulted in significant medial over-resection. Clinical outcomes and ROM improved significantly for all patients, except for internal rotation in the GA group. There were no other significant differences between the two groups, neither in terms of post-operative scores nor in terms of clinical net improvements, nor tendon repair integrity. This computer-assisted planning for acromioplasty during RCR proved no benefits in terms of bone removal, tendon healing, or clinical outcomes. Nonetheless such planning tools could help less experienced surgeons improve the efficacy of acromioplasty. I, Randomized controlled trial (Therapeutic study)
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