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Background & Aim: We investigated the combination of rapid antigen detection (RAD) and RT-qPCR assays in a stepwise procedure to optimize the detection of COVID-19., Methods: From August 2020 to November 2020, 43,399 patients were screened in our laboratory for COVID-19 diagnostic by RT-qPCR using nasopharyngeal swab. Overall, 4,691 of the 43,399 were found to be positive, and 200 were retrieved for RAD testing allowing comparison of diagnostic accuracy between RAD and RT-qPCR. Cycle threshold (Ct) and time from symptoms onset (TSO) were included as covariates., Results: The overall sensitivity, specificity, PPV, NPV, LR-, and LR+ of RAD compared with RT-qPCR were 72% (95%CI 62%-81%), 99% (95% CI95%-100%), 99% (95%CI 93%-100%), and 78% (95%CI 70%-85%), 0.28 (95%CI 0.21-0.39), and 72 (95%CI 10-208) respectively. Sensitivity was higher for patients with Ct ≤ 25 regardless of TSO: TSO ≤ 4 days 92% (95%CI 75%-99%), TSO > 4 days 100% (95%CI 54%-100%), and asymptomatic 100% (95%CI 78-100%). Overall, combining RAD and RT-qPCR would allow reducing from only 4% the number of RT-qPCR needed., Conclusions: This study highlights the risk of misdiagnosing COVID-19 in 28% of patients if RAD is used alone. A stepwise analysis that combines RAD and RT-qPCR would be an efficient screening procedure for COVID-19 detection and may facilitate the control of the outbreak., Competing Interests: The authors have declared that no competing interests exist.

Background: In myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), altered membrane excitability often occurs in exercising muscles demonstrating muscle dysfunction regardless of any psychiatric disorder. Increased oxidative stress is also present in many ME/CFS patients and could affect the membrane excitability of resting muscles., Methods: Seventy-two patients were examined at rest, during an incremental cycling exercise and during a 10-min post-exercise recovery period. All patients had at least four criteria leading to a diagnosis of ME/CFS. To explore muscle membrane excitability, M-waves were recorded during exercise (rectus femoris (RF) muscle) and at rest (flexor digitorum longus (FDL) muscle). Two plasma markers of oxidative stress (thiobarbituric acid reactive substance (TBARS) and oxidation-reduction potential (ORP)) were measured. Plasma potassium (K + ) concentration was also measured at rest and at the end of exercise to explore K + outflow., Results: Thirty-nine patients had marked M-wave alterations in both the RF and FDL muscles during and after exercise while the resting values of plasma TBARS and ORP were increased and exercise-induced K + outflow was decreased. In contrast, 33 other patients with a diagnosis of ME/CFS had no M-wave alterations and had lower baseline levels of TBARS and ORP. M-wave changes were inversely proportional to TBARS and ORP levels., Conclusions: Resting muscles of ME/CFS patients have altered muscle membrane excitability. However, our data reveal heterogeneity in some major biomarkers in ME/CFS patients. Measurement of ORP may help to improve the diagnosis of ME/CFS. Trial registration Ethics Committee "Ouest II" of Angers (May 17, 2019) RCB ID: number 2019-A00611-56.

Background: Maximal handgrip strength is used to predict exercise performance in healthy older subjects and in patients with chronic obstructive pulmonary disease, breast cancer or cirrhosis. Our objective was to evaluate the ability of maximal handgrip strength to predict maximal exercise performance in patients with chronic fatigue., Methods: Sixty-six patients with myalgic encephalomyelitis/chronic fatigue syndrome and 32 patients with chronic fatigue but no diagnosis of myalgic encephalomyelitis/chronic fatigue syndrome were included. The maximal physical performance was measured on a cycle ergometer to measure the peak oxygen uptake and the maximal work rate. We searched for linear regressions between maximal handgrip strength and maximal performances., Findings: No significant differences in slopes and ordinates of regression lines were noted between patients with or without a diagnosis of myalgic encephalomyelitis/chronic fatigue syndrome, allowing to pool the data. Maximal handgrip strength was significantly and positively correlated with peak oxygen uptake and maximal work rate in all patients with chronic fatigue., Interpretation: We conclude that handgrip strength can predict maximal exercise performance in patients with chronic fatigue., Competing Interests: Declaration of competing interest None to declare., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Background: Evidence is growing regarding the ability of platelet-rich plasma (PRP) injections to enhance functional capacity and alleviate pain in knee osteoarthritis (OA). However, heterogeneity in common practice regarding PRP preparation and biological content makes the initiation of this activity in a hospital complex. The aim of this study was to document the efficacy of a single PRP injection to treat knee OA and validate a routine care procedure., Methods: Fifty-seven patients with symptomatic knee OA received a single injection of large volume of very pure PRP. They were assessed at baseline and after one, three and six months, by measuring Knee Injury and Osteoarthritis Score (KOOS), Observed Pain after a 50-foot walk test and Visual Analog Scale (VAS) assessments. Magnetic Resonance Imaging (MRI) analysis was performed at baseline and six months after the procedure. The objective was to recover 50% of responders three months after the procedure using OMERACT-OARSI criteria., Results: A single administration of high volume pure PRP provided significant clinical benefit for 84.2% of the responders, three months after the procedure. The KOOS total score significantly increased from 43.5 ± 14.3 to 66.4 ± 21.7 six months after the procedure ( p < 0.001). Pain also significantly decreased from 37.5 ± 25.1 to 12.9 ± 20.9 ( p < 0.001). No difference was observed on MRI parameters., Conclusion: A single injection of large volume of very pure PRP is associated with significant functional improvement and pain relief, allowing initiation of daily PRP injection within our hospital., Competing Interests: The authors declare no conflict of interest.

HfO 2 -based resistive oxide memories are studied by core-level spectromicroscopy using a laboratory-based X-ray photoelectron emission microscope (XPEEM). After forming, the top electrode is thinned to about 1 nm for the XPEEM analysis, making the buried electrode/HfO 2 interface accessible whilst preserving it from contamination. The results are obtained in the true photoemission channel mode from individual memory cells (5 × 5 µm) excited by low-flux laboratory X-rays, in contrast to most studies employing the X-ray absorption channel using potentially harmful bright synchrotron X-rays. Analysis of the local Hf 4f, O 1s and Ti 2p core level spectra yields valuable information on the chemistry of the forming process in a single device, and in particular the central role of oxygen vacancies thanks to the spectromicroscopic approach., (Copyright © 2017 Elsevier B.V. All rights reserved.)