484 research outputs found

    Performance of the EUDET-type beam telescopes

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    Test beam measurements at the test beam facilities of DESY have been conducted to characterise the performance of the EUDET-type beam telescopes originally developed within the EUDET project. The beam telescopes are equipped with six sensor planes using MIMOSA26 monolithic active pixel devices. A programmable Trigger Logic Unit provides trigger logic and time stamp information on particle passage. Both data acquisition framework and offline reconstruction software packages are available. User devices are easily integrable into the data acquisition framework via predefined interfaces. The biased residual distribution is studied as a function of the beam energy, plane spacing and sensor threshold. Its standard deviation at the two centre pixel planes using all six planes for tracking in a 6\,GeV electron/positron-beam is measured to be (2.88\,\pm\,0.08)\,\upmu\meter.Iterative track fits using the formalism of General Broken Lines are performed to estimate the intrinsic resolution of the individual pixel planes. The mean intrinsic resolution over the six sensors used is found to be (3.24\,\pm\,0.09)\,\upmu\meter.With a 5\,GeV electron/positron beam, the track resolution halfway between the two inner pixel planes using an equidistant plane spacing of 20\,mm is estimated to (1.83\,\pm\,0.03)\,\upmu\meter assuming the measured intrinsic resolution. Towards lower beam energies the track resolution deteriorates due to increasing multiple scattering. Threshold studies show an optimal working point of the MIMOSA26 sensors at a sensor threshold of between five and six times their RMS noise. Measurements at different plane spacings are used to calibrate the amount of multiple scattering in the material traversed and allow for corrections to the predicted angular scattering for electron beams

    Comparison of Habitual and Maximal Gait Speed and their Impact on Sarcopenia Quantification in German Nursing Home Residents.

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    OBJECTIVES Sarcopenia is characterized by loss of muscle strength and muscle mass. The EWGSOP2 specifications include physical functioning determination for quantification of the sarcopenia severity. However, there is a lack in the use of habitual and maximal gait speed and their influence on sarcopenia quantification. We hypothesize differences in sarcopenia quantification using habitual and maximal gait speed. METHODS Sixty-six residents from five nursing homes were examined. Habitual and maximal gait speed were measured by 4-meter-walking-Test. McNemar-Test and χ2-test were used to identify quantification differences. Effect sizes of both gait speeds were calculated with Spearman's rank-correlation-coefficient. RESULTS Significant difference was identified for twenty-two residents in physical functioning classification by McNemar-Test (p<.001). χ2-Test identified a significant frequency distribution for sarcopenia categories between both gait speeds (χ2 (df2)=11.215, p=.004; Cramer's V=.412). Significant correlations (p<.05) were only shown for maximal gait speed in variables falls in the last three months (|rs|=.326), Barthel-Index (|rs|=.415), and SARC-F (|rs|=.335). CONCLUSIONS The use of habitual and maximal gait speed has a significant impact on sarcopenia quantification in nursing home residents. An adapted standardization in the EWGSOP2 specifications should follow

    Allograft Versus Autograft Osteochondral Transplant for Chondral Defects of the Talus: Systematic Review and Meta-analysis.

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    BACKGROUND: It is unclear whether the results of osteochondral transplant using autografts or allografts for talar osteochondral defect are equivalent. PURPOSE: A systematic review of the literature was conducted to compare allografts and autografts in terms of patient-reported outcome measures (PROMs), MRI findings, and complications. STUDY DESIGN: Systematic review; Level of evidence, 4. METHODS: This study was conducted according to the PRISMA guidelines. The literature search was conducted in February 2021. All studies investigating the outcomes of allograft and/or autograft osteochondral transplant as management for osteochondral defects of the talus were accessed. The outcomes of interest were visual analog scale (VAS) score for pain, American Orthopaedic Foot and Ankle Society (AOFAS) score, and Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score. Data concerning the rates of failure and revision surgery were also collected. Continuous data were analyzed using the mean difference (MD), whereas binary data were evaluated with the odds ratio (OR) effect measure. RESULTS: Data from 40 studies (1174 procedures) with a mean follow-up of 46.5 ± 25 months were retrieved. There was comparability concerning the length of follow-up, male to female ratio, mean age, body mass index, defect size, VAS score, and AOFAS score (P > .1) between the groups at baseline. At the last follow-up, the MOCART (MD, 10.5; P = .04) and AOFAS (MD, 4.8; P = .04) scores were better in the autograft group. The VAS score was similar between the 2 groups (P = .4). At the last follow-up, autografts demonstrated lower rate of revision surgery (OR, 7.2; P < .0001) and failure (OR, 5.1; P < .0001). CONCLUSION: Based on the main findings of the present systematic review, talar osteochondral transplant using allografts was associated with higher rates of failure and revision compared with autografts at midterm follow-up

    Surgical management of focal chondral defects of the knee: a Bayesian network meta-analysis.

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    BACKGROUND: Focal chondral defects of the knee are common. Several surgical techniques have been proposed for the management of chondral defects: microfractures (MFX), osteochondral autograft transplantation (OAT), autologous matrix-induced chondrogenesis (AMIC) and autologous chondrocyte implantation (ACI)-first generation (pACI), second generation (cACI) and third generation (mACI). A Bayesian network meta-analysis was conducted to compare these surgical strategies for chondral defects in knee at midterm follow-up. METHODS: This Bayesian network meta-analysis was conducted according to the PRISMA extension statement for reporting of systematic reviews incorporating network meta-analyses of health care interventions. PubMed, Google Scholar, Embase and Scopus databases were accessed in July 2021. All the prospective comparative clinical trials investigating two or more surgical interventions for chondral defects of the knee were accessed. The network meta-analyses were performed through a Bayesian hierarchical random-effects model analysis. The log odds ratio (LOR) effect measures were used for dichotomic variables, while the standardized mean difference (SMD) for the continuous variables. RESULTS: Data from 2220 procedures (36 articles) were retrieved. The median follow-up was 36 (24 to 60) months. The ANOVA test found good baseline comparability between symptoms duration, age, sex and body mass index. AMIC resulted in higher Lysholm score (SMD 3.97) and Tegner score (SMD 2.10). AMIC demonstrated the lowest rate of failures (LOR -0.22) and the lowest rate of revisions (LOR 0.89). As expected, MFX reported the lower rate of hypertrophy (LOR -0.17) followed by AMIC (LOR 0.21). No statistically significant inconsistency was found in the comparisons. CONCLUSION: AMIC procedure for focal chondral defects of the knee performed better overall at approximately 3 years' follow-up

    Isolated medial patellofemoral ligament reconstruction for recurrent patellofemoral instability: analysis of outcomes and risk factors.

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    BACKGROUND: The medial patellofemoral ligament (MPFL) is always damaged after patellar dislocation. In selected patients, MPFL reconstruction is necessary to restore a correct patellar tracking. Despite the large number of different techniques reported to reconstruct the MPFL, there is no consensus concerning the optimal procedure, and debates is still ongoing. The present study analysed the results after isolated MPFL reconstruction in patients with patellofemoral instability. Furthermore, a subgroup analysis of patients presenting pathoanatomical risk factors was made. METHODS: In November 2020, the main electronic databases were accessed. All articles reporting the results of primary isolated MPFL reconstruction for recurrent patellofemoral instability were considered for inclusion. Only articles reporting a minimum 12-month follow-up were eligible. RESULTS: Data from a total of 1777 knees were collected. The mean age of the patients involved was 22.8 ± 3.4 years. The mean follow-up was 40.7 ± 25.8 months. Overall, the range of motion (+ 27.74; P < 0.0001) and all the other scores of interests improved at last follow-up: Kujala (+ 12.76; P = 0.0003), Lysholm (+ 15.69; P < 0.0001), Tegner score (+ 2.86; P = 0.006). Seventy-three of 1780 patients (4.1%) showed a positive apprehension test. Thirty of 1765 patients (1.7%) experienced re-dislocations, while 56 of 1778 patients (3.2%) showed persisting joint instability. Twenty-five of 1786 patients (1.4%) underwent revision surgeries. CONCLUSION: Isolated MPFL reconstruction for recurrent patellofemoral instability provides reliable surgical outcomes. Patients with pathoanatomical predisposing factors reported worse surgical outcomes

    Autologous Matrix Induced Chondrogenesis (AMIC) Compared to Microfractures for Chondral Defects of the Talar Shoulder: A Five-Year Follow-Up Prospective Cohort Study.

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    INTRODUCTION: Many procedures are available to manage cartilage defects of the talus, including microfracturing (MFx) and Autologous Matrix Induced Chondrogenesis (AMIC). Whether AMIC or MFx are equivalent for borderline sized defects of the talar shoulder is unclear. Thus, the present study compared the efficacy of primary isolated AMIC versus MFx for borderline sized focal unipolar chondral defects of the talar shoulder at midterm follow-up. METHODS: Patients undergoing primary isolated AMIC or MFx for focal unipolar borderline sized chondral defects of the talar shoulder were recruited prospectively. For those patients who underwent AMIC, a type I/III collagen resorbable membrane was used. The outcomes of interest were: Visual Analogic Scale (VAS), Tegner Activity Scale, American Orthopedic Foot and Ankle Score (AOFAS). The Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) was assessed by a blinded radiologist, who had not been involved in the clinical management of the patients. Data concerning complication rate and additional procedures were also collected. RESULTS: The mean follow-up was 43.5 months. The mean age of the 70 patients at operation was 32.0 years, with a mean defect size of 2.7 cm2. The mean length of hospitalization was shorter in the MFx cohort (p = 0.01). No difference was found between the two cohorts in terms of length of prior surgery symptoms and follow-up, mean age and BMI, sex and side, and defect size. At a mean follow-up of 43.5 months, the AOFAS (p = 0.03), VAS (p = 0.003), and Tegner (p = 0.01) scores were greater in the AMIC group. No difference was found in the MOCART score (p = 0.08). The AMIC group evidenced lower rates of reoperation (p = 0.008) and failure (p = 0.003). CONCLUSION: At midterm follow-up, AMIC provides better results compared to MFx

    Not Every Hit-Identification Technique Works on 1-Deoxy-D-Xylulose 5-Phosphate Synthase (DXPS):Making the Most of a Virtual Screening Campaign

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    In this work, we demonstrate how important it is to investigate not only on-target activity but to keep antibiotic activity against critical pathogens in mind. Since antimicrobial resistance is spreading in bacteria such as Mycobacterium tuberculosis, investigations into new targets are urgently needed. One promising new target is 1-deoxy-D-xylulose 5-phosphate synthase (DXPS) of the 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway. We have recently solved the crystal structure of truncated M. tuberculosis DXPS and used it to perform a virtual screening in collaboration with Atomwise Inc. using their deep convolutional neural network-based AtomNet® platform. Of 94 virtual hit compounds only one showed interesting results in binding and activity studies. We synthesized 30 close derivatives using a straightforward synthetic route that allowed for easy derivatization. However, no improvement in activity was observed for any of the derivatives. Therefore, we tested them against a variety of pathogens and found them to be good inhibitors against Escherichia coli.</p

    Arthroscopy versus mini-arthrotomy approach for matrix-induced autologous chondrocyte implantation in the knee: a systematic review.

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    BACKGROUND: Matrix-induced autologous chondrocyte implantation (mACI) can be performed in a full arthroscopic or mini-open fashion. A systematic review was conducted to investigate whether arthroscopy provides better surgical outcomes compared with the mini-open approach for mACI in the knee at midterm follow-up. METHODS: This systematic review was conducted following the PRISMA guidelines. The literature search was performed in May 2021. All the prospective studies reporting outcomes after mACI chondral defects of the knee were accessed. Only studies that clearly stated the surgical approach (arthroscopic or mini-open) were included. Only studies reporting a follow-up longer than 12 months were eligible. Studies reporting data from combined surgeries were not eligible, nor were those combining mACI with less committed cells (e.g., mesenchymal stem cells). RESULTS: Sixteen studies were included, and 770 patients were retrieved: 421 in the arthroscopy group, 349 in the mini-open. The mean follow-up was 44.3 (12-60) months. No difference between the two groups was found in terms of mean duration of symptoms, age, body mass index (BMI), gender, defect size (P > 0.1). No difference was found in terms of Tegner Score (P = 0.3), Lysholm Score (P = 0.2), and International Knee Documentation Committee (IKDC) Score (P = 0.1). No difference was found in the rate of failures (P = 0.2) and revisions (P = 0.06). CONCLUSION: Arthroscopy and mini-arthrotomy approaches for mACI in knee achieve similar outcomes at midterm follow-up. LEVEL OF EVIDENCE: II, systematic review of prospective studies
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