Distributed Sum-Rate Maximization of Cellular Communications with Multiple Reconfigurable Intelligent Surfaces

The technology of Reconfigurable Intelligent Surfaces (RISs) has lately attracted considerable interest from both academia and industry as a low-cost solution for coverage extension and signal propagation control. In this paper, we study the downlink of a multi-cell wideband communication system comprising single-antenna Base Stations (BSs) and their associated single-antenna users, as well as multiple passive RISs. We assume that each BS controls a separate RIS and performs Orthogonal Frequency Division Multiplexing (OFDM) transmissions. Differently from various previous works where the RIS unit elements are considered as frequency-flat phase shifters, we model them as Lorentzian resonators and present a joint design of the BSs' power allocation, as well as the phase profiles of the multiple RISs, targeting the sum-rate maximization of the multi-cell system. We formulate a challenging distributed nonconvex optimization problem, which is solved via successive concave approximation. The distributed implementation of the proposed design is discussed, and the presented simulation results showcase the interplay of the various system parameters on the sum rate, verifying the performance boosting role of RISs.Comment: 5 pages, 1 figure. Presented in IEEE SPAWC 202

Interventional radiology in the elderly

Interventional radiological percutaneous procedures are becoming all the more important in the curative or palliative management of elderly frail patients with multiple underlying comorbidities. They may serve either as alternative primary minimally invasive therapies or adjuncts to traditional surgical treatments. The present report provides a concise review of the most important interventional radiological procedures with a special focus on the treatment of the primary debilitating pathologies of the elderly population. The authors elaborate on the scientific evidence and latest developments of thermoablation of solid organ malignancies, palliative stent placement for gastrointestinal tract cancer, airway stenting for tracheobronchial strictures, endovascular management of aortic and peripheral arterial vascular disease, and cement stabilization of osteoporotic vertebral fractures. The added benefits of high technical and clinical success coupled with lower procedural mortality and morbidity are highlighted

Research gaps in diet and nutrition in inflammatory bowel disease. A topical review by D-ECCO Working Group (Dietitians of ECCO)

Although the current doctrine of IBD pathogenesis proposes an interaction between environmental factors with gut microbiota in genetically-susceptible individuals, dietary exposures have attracted recent interest and are, at least in part, likely to explain the rapid rise in disease incidence and prevalence. The D-ECCO working group along with other ECCO experts with expertise in nutrition, microbiology, physiology and medicine reviewed the evidence investigating the role of diet and nutritional therapy in the onset, perpetuation and management of IBD. A narrative topical review is presented where evidence pertinent to the topic is summarized collectively under three main thematic domains: i) the role of diet as an environmental factor in IBD aetiology; ii) the role of diet as induction and maintenance therapy in IBD; and iii) assessment of nutritional status and supportive nutritional therapy in IBD. A summary of research gaps for each of these thematic domains is proposed which is anticipated to be agenda setting for future research in the area of diet and nutrition in IBD

Power Minimizing MEC Offloading with QoS Constraints over RIS-Empowered Communications

This work lies at the intersection of two cutting edge technologies envisioned to proliferate in future 6G wireless systems: Multi-access Edge Computing (MEC) and Reconfigurable Intelligent Surfaces (RISs). While the former will bring a powerful information technology environment at the wireless edge, the latter will enhance communication performance, thanks to the possibility of adapting wireless propagation as per end users' convenience, according to specific service requirements. We propose a joint optimization of radio, computing, and wireless environment reconfiguration through an RIS, with the goal of enabling low power computation offloading services with reliability guarantees. Going beyond previous works on this topic, multi-carrier frequency selective RIS elements' responses and wireless channels are considered. This opens new challenges in RIS optimization, accounting for frequency dependent RIS response profiles, which strongly affect RIS-aided wireless links and, as a consequence, MEC service performance. We formulate an optimization problem accounting for short and long-term constraints involving device transmit power allocation across multiple subcarriers and local computing resources, as well as RIS reconfiguration parameters according to a recently developed Lorentzian model. Besides a theoretical optimization framework, numerical results show the effectiveness of the proposed method in enabling low power reliable computation offloading over RIS-aided frequency selective channels.Comment: IEEE GLOBECOM 202

Platelet Responsiveness to Clopidogrel Treatment After Peripheral Endovascular Procedures The PRECLOP Study: Clinical Impact and Optimal Cutoff Value of On-Treatment High Platelet Reactivity

ObjectivesThis study aimed to assess the clinical implications and optimal cutoff value of high platelet reactivity (HPR) in patients receiving clopidogrel for peripheral endovascular procedures.BackgroundAs noted in coronary studies, HPR could be related to increased adverse events.MethodsThis prospective trial included patients receiving clopidogrel 75 mg daily, before and after infrainguinal angioplasty or stenting. Platelet inhibition was assessed with the VerifyNow P2Y12 point-of-care test. Primary endpoints were 1-year clinical events rate (composite endpoint of death, major stroke, major amputation, target vessel revascularization, and bypass) according to the P2Y12 reaction units (PRU)-based quartile distribution, the estimation of the optimal PRU cutoff value for predicting clinical outcome, and the identification of independent predictors influencing event-free survival.ResultsIn total, 100 consecutive patients were enrolled. The 1-year cumulative events rate was 4% in the first quartile, 12% in the second, 52% in the third, and 84% in the fourth. Pairwise comparisons demonstrated a significant difference in the composite endpoint between successive quartiles (all p < 0.05 except for the first vs. second quartile). According to receiver-operating characteristic curve analysis, the optimal cutoff value for the composite endpoint was PRU ≥234 (area under the curve: 0.883; 95% confidence interval [CI]: 0.811 to 0.954; p < 0.0001; sensitivity: 92.1%; specificity: 84.2%). Cox multivariate regression analysis identified HPR (PRU ≥234) as the only independent predictor of an increased number of adverse events (hazard ratio: 16.9; 95% CI: 5 to 55; p < 0.0001).ConclusionsOn-treatment HPR is associated with markedly increased adverse clinical events in patients undergoing peripheral endovascular procedures. Point-of-care clopidogrel assessment might be useful in individualizing antiplatelet therapy to attain superior clinical results. (High On-Treatment Platelet Reactivity Following Peripheral Endovascular Procedures [PRECLOP]; NCT01744613

Tumoral and non-tumoral trachea stenoses: evaluation with three-dimensional CT and virtual bronchoscopy

<p>Abstract</p> <p>Background</p> <p>We evaluated the ability of 3D-CT and virtual bronchoscopy to estimate trachea stenosis in comparison to conventional axial CT and fiberoptic bronchoscopy, with a view to assist thoracic surgeons in depicting the anatomical characteristics of tracheal strictures.</p> <p>Methods</p> <p>Spiral CT was performed in 16 patients with suspected tracheal stenoses and in 5 normal subjects. Tracheal stenoses due to an endoluminal neoplasm were detected in 13 patients, whilst post-intubation tracheal stricture was observed in the other 3 patients. Multiplanar reformatting (MPR), volume rendering techniques (VRT) and virtual endoscopy (VE) for trachea evaluation were applied and findings were compared to axial CT and fiberoptic bronchoscopy. The accuracy of the procedure in describing the localization and degree of stenosis was tested by two radiologists in a blinded controlled trial.</p> <p>Results</p> <p>The imaging modalities tested showed the same stenoses as the ones detected by flexible bronchoscopy and achieved accurate and non-invasive morphological characterization of the strictures, as well as additional information about the extraluminal extent of the disease. No statistically significant difference was observed between the bronchoscopic findings and the results of axial CT estimations (P = 1.0). No statistically significant differences were observed between bronchoscopic findings and the MPR, VRT and VE image evaluations (P = 0.705, 0.414 and 0.414 respectively).</p> <p>Conclusion</p> <p>CT and computed generated images may provide a high fidelity, noninvasive and reproducible evaluation of the trachea compared to bronchoscopy. They may play a role in assessment of airway patency distal to high-grade stenoses, and represent a reliable alternative method for patients not amenable to conventional bronchoscopy.</p

A multicentre study of nutrition risk assessment in adult patients with inflammatory bowel disease attending outpatient clinics

Background: Overnutrition and undernutrition can affect patients with inflammatory bowel disease (IBD). Although all IBD outpatients should be screened for nutrition risk, screening is not routinely performed, potentially leading to reduced identification and treatment. This study aimed to estimate the prevalence of nutrition risk in adult IBD outpatients and the proportion of cases who discussed diet and/or nutrition during their routine clinical appointment. Methods: Adults with IBD attending outpatient clinics at four hospitals in Greece and in UK were recruited. Demographic and anthropometric data were collected using face-to-face patient interviews and clinical records. Patients were classified as high (i.e. BMI &lt;18.5kg/m2 or 18.5-54 20kg/m2 and weight loss &gt;5%), moderate (i.e. BMI 20-25 kg/m2 and weight loss &gt;5%) or low risk of undernutrition and high risk of obesity (i.e. BMI 25-30% and weight gain &gt;5%). The proportion of patients who discussed diet and/or nutrition during their clinical appointment was calculated. Results: In total, 390 IBD patients participated. Sixteen (4%) patients were underweight, 113 (29%) were overweight and 71 (18%) were obese. Twenty-one (5%) patients were at high risk of undernutrition; of these four (19%) were under dietetic care. Of those at high risk of undernutrition, 11 (52%) had discussed diet and/or nutrition during their routine clinical appointment. Fifty-six (14%) patients had gained more than 5% weight since their last recorded/reported weight and 19 (5%) were at high risk of obesity. Conclusions: Few patients were identified to be at high risk of undernutrition and less than a fifth of these were under dietetic care. Overnutrition is a growing problem in IBD with almost half of adult patients being overweight or obese. Diet and/or nutrition were not routinely discussed in this group of IBD outpatients

Emerging Stent and Balloon Technologies in the Femoropopliteal Arteries

Endovascular procedures for the management of the superficial femoral (SFA) and popliteal artery disease are increasingly common. Over the past decade, several stent technologies have been established which may offer new options for improved clinical outcomes. This paper reviews the current evidence for SFA and popliteal artery angioplasty and stenting, with a focus on randomized trials and registries of nitinol self-expanding stents, drug-eluting stents, dug-coated balloons, and covered stent-grafts. We also highlight the limitations of the currently available data and the future routes in peripheral arterial disease (PAD) stent and balloon technology