Système multi-antennaires bi-fréquence miniaturisé pour liaison MIMO 4X4

National audienceUn dispositif multi-antennaires pour systèmes MIMO est présenté dans cet article. L'antenne élémentaire utilisée est bi-fréquence afin de couvrir les différentes bandes de la norme WiFi. Les performances du dispositif sont présentées et également évaluées dans un contexte MIMO

Measurement of finite-frequency current statistics in a single-electron transistor

Electron transport in nano-scale structures is strongly influenced by the Coulomb interaction which gives rise to correlations in the stream of charges and leaves clear fingerprints in the fluctuations of the electrical current. A complete understanding of the underlying physical processes requires measurements of the electrical fluctuations on all time and frequency scales, but experiments have so far been restricted to fixed frequency ranges as broadband detection of current fluctuations is an inherently difficult experimental procedure. Here we demonstrate that the electrical fluctuations in a single electron transistor (SET) can be accurately measured on all relevant frequencies using a nearby quantum point contact for on-chip real-time detection of the current pulses in the SET. We have directly measured the frequency-dependent current statistics and hereby fully characterized the fundamental tunneling processes in the SET. Our experiment paves the way for future investigations of interaction and coherence induced correlation effects in quantum transport.Comment: 7 pages, 3 figures, published in Nature Communications (open access

Inhibiting LXRα phosphorylation in hematopoietic cells reduces inflammation and attenuates atherosclerosis and obesity in mice

Atherosclerosis and obesity share pathological features including inflammation mediated by innate and adaptive immune cells. LXRα plays a central role in the transcription of inflammatory and metabolic genes. LXRα is modulated by phosphorylation at serine 196 (LXRα pS196), however, the consequences of LXRα pS196 in hematopoietic cell precursors in atherosclerosis and obesity have not been investigated. To assess the importance of LXRα phosphorylation, bone marrow from LXRα WT and S196A mice was transplanted into Ldlr-/- mice, which were fed a western diet prior to evaluation of atherosclerosis and obesity. Plaques from S196A mice showed reduced inflammatory monocyte recruitment, lipid accumulation, and macrophage proliferation. Expression profiling of CD68+ and T cells from S196A mouse plaques revealed downregulation of pro-inflammatory genes and in the case of CD68+ upregulation of mitochondrial genes characteristic of anti-inflammatory macrophages. Furthermore, S196A mice had lower body weight and less visceral adipose tissue; this was associated with transcriptional reprograming of the adipose tissue macrophages and T cells, and resolution of inflammation resulting in less fat accumulation within adipocytes. Thus, reducing LXRα pS196 in hematopoietic cells attenuates atherosclerosis and obesity by reprogramming the transcriptional activity of LXRα in macrophages and T cells to promote an anti-inflammatory phenotype

Effects of sildenafil on maximum walking time in patients with arterial claudication: The ARTERIOFIL study

BACKGROUND: Patients with lower extremity peripheral artery disease (PAD) frequently experience claudication, a clinical symptom indicative of reduced walking capacity. Recommended care consists of exercise rehabilitation combined with optimal medical treatment and surgery. The effects of a single oral dose of sildenafil, a phosphodiesterase type-5 inhibitor, on patients with claudication are discussed. The aim of this study was to test the efficacy of a single 100 mg dose of sildenafil compared to placebo in terms of maximal walking time (MWT) in patients with claudication. METHODS: The ARTERIOFIL study is a crossover, double-blind, prospective, randomized, single-center study conducted at Angers University Hospital in France. MWT (primary endpoint) was assessed using a treadmill test (10% incline; 3.2 km/h). Secondary endpoints (pain-free walking time (PFWT), transcutaneous oximetry during exercise and redox cycle parameters and safety) were also studied. RESULTS: Fourteen patients were included of whom two were ultimately excluded. In the 12 remaining patients, the MWT was significantly improved during the sildenafil period compared with the placebo period (300 s [95% CI 172 s-428 s] vs 402 s [95% CI 274 s-529 s] p < 0.01). Sildenafil had no significant effect on pain-free walking time or skin tissue oxygenation during exercise. According to redox cycle parameters, sildenafil significantly reduced blood glucose and pyruvate levels and the 3-hydroxybutyrate/acetoacetate ratio, while there was no significant effect on lactate, 3-hydroxybutyrate, acetoacetate and free fatty acid levels. Symptomatic transient hypotension was observed in two women. CONCLUSIONS: The ARTERIOFIL study has shown that a single 100 mg oral dose of sildenafil had a significant effect on increase in MWT but had no significant effects on PFWT and oxygenation parameters in patients with claudication. A double-blind, prospective, randomized, multicenter study (VIRTUOSE©) is ongoing to evaluate the chronic effect of six month-long sildenafil treatment on MWT in PAD patients with claudication. CLINICAL TRIAL REGISTRATION: This clinical trial was registered at clinicaltrials.gov, registration. number: NCT02832570, (https://clinicaltrials.gov/ct2/show/NCT02832570)

Promoting the use of Motor Function Measure (MFM) as outcome measure in patients with Duchenne Muscular Dystrophy (DMD) treated by corticosteroids

ObjectivesAssessing muscle function is a key step in measuring changes and evaluating the outcomes of therapeutic interventions in Duchenne Muscular Dystrophy (DMD). Regarding the large use of corticosteroids (CS) in this population to delay the loss of function, our goal was to monitor the evolution of motor function in patients with DMD treated by corticosteroids (CS) and to study the responsiveness of Motor Function Measure (MFM) in this population in order to provide an estimation of the number of subject needed for a clinical trial.MethodA total of 76 patients with DMD, aged 5.9 to 11.8 years, with at least 6 months of follow-up and 2 MFM were enrolled, 30 in the CS treated group (8±1.62 y) and 46 in the untreated group (7.91±1.50 y).ResultsThe relationship between MFM scores and age was studied in CS treated patients and untreated patients. The evolution of these scores was compared between groups, on a 6-, 12- and 24-month period by calculating slopes of change and standardized response mean. At 6, 12 and 24 months, significant differences in the mean score change were found, for all MFM scores, between CS treated patients and untreated patients. For D1 subscore specifically, at 6 months, the increase is significant in the treated group (11.3±14%/y; SRM 0.8) while a decrease is observed in the untreated group (–17.8±17.7%/y; SRM 1). At 12 and 24 months, D1 subscore stabilized for treated patients but declined significantly for untreated boys (–15.5±15.1%/y; SRM 1 at 12 mo and–18.8±7.1%/y; SRM 2.6 at 24 mo). 21 patients lost the ability to walk during the study: 6 in the CS treated group (25% at 24 months, mean age: 10.74±1.28 y) and 15 in the untreated group (64.71% at 24 months, mean age: 9.20±1.78 y).Discussion and conclusionPatients with DMD treated by CS present a different course of the disease described in this paper using the MFM. Based on these results, an estimation of the number of patients needed for clinical trial could be done

The risk of recurrent venous thromboembolism after discontinuation of anticoagulant therapy in patients with cancer-associated thrombosis:a systematic review and meta-analysis

Background: The optimal duration of anticoagulation in patients with active cancer and venous thromboembolism (VTE) is unknown. Current clinical guidelines advocate anticoagulant therapy for 3–6 months and to continue anticoagulant therapy for as long as the cancer is active. However, an adequate systematic review on the rate of recurrent VTE after discontinuation of anticoagulant therapy has not been performed. Methods: For this systemic review and meta-analysis, we searched Embase.com, Medline (Ovid), Web of Science, Cochrane Library, and Google Scholar, from database inception to February 16, 2023, for studies on anticoagulant therapy in patients with cancer and the recurrence of venous thromboembolism after discontinuation of this therapy. We included randomised controlled trials and cohort studies published in English that reported on patients who met the following: cancer and a first VTE, completed at least 3 months of anticoagulant therapy, were followed after discontinuation of anticoagulant therapy, and with symptomatic recurrent VTE as an outcome during follow-up. Study-level data were requested from study authors. The primary outcome was the rate of recurrent VTE after discontinuation of anticoagulant therapy. A Bayesian random-effects meta-analysis was used to estimate the rate of recurrent VTE per 100 person-years for the pooled studies at different time intervals after discontinuation of anticoagulation therapy. We also calculated the cumulative VTE recurrence rate at different time intervals. Forest plots were mapped and the results were summarized by the median and 95% credible interval (CIs). This study was registered with PROSPERO, CRD42021249060. Findings: Of 3856 studies identified in our search, 33 studies were identified for inclusion. After requesting study-level data, 14 studies involving 1922 patients with cancer-associated thrombosis were included. The pooled rate of recurrent VTE per 100 person-years after discontinuation of anticoagulant therapy was 14.6 events (95% credible interval 6.5–22.8) in the first three months, decreasing to 1.1 events (95% CI 0.3–2.1) in year 2–3, and 2.2 events (95% CI 0.0–4.4) in year 3–5 after discontinuation of anticoagulant therapy. The cumulative VTE recurrence rate was 28.3% (95% CI 15.6–39.6%) at 1 year; 31.1% (95% CI 16.5–43.8%) at 2 years; 31.9% (95% CI 16.8–45.0%) at 3 years; and 35.0% (95% CI 16.8–47.4%) at 5 years after discontinuation of anticoagulant therapy. Interpretation: This meta-analysis demonstrates a high rate of recurrent VTE over time after discontinuation of anticoagulant therapy in patients with cancer-associated thrombosis. Our results support the current clinical guidelines to continue anticoagulant therapy in patients with active cancer. Funding: Erasmus MC.</p