PIV measurements over a double bladed Darrieus-type vertical axis wind turbine: A validation benchmark

Vertical axis wind turbines (VAWTs) are very attractive for in-home power generation since they can be adopted even at low wind speeds and highly variable wind direction. Even if significant experimental research activity has been carried out to improve VAWTs performance, the ability to accurately reproduce flow field characteristics around turbine blades by CFD (computational fluid dynamics) techniques represents a powerful approach to further enhance wind turbines performance. Thanks to CFD, in fact, it is possible to reproduce flow characteristics with a detail level impossible to achieve by experiments. Nevertheless, in order to appropriately analyze the flow structure by CFD application, an accurate validation is essential, and high-quality measurements of some main flow characteristics are required. In recent publications the authors investigated, both experimentally and numerically, the performance of an innovative double bladed Darrieus-type VAWT, with the aim to define an optimal configuration also focusing on self-starting ability of the prototype by employing CFD technique. Nevertheless, comparison between experiments and numerical results was made only in terms of power and torque coefficient. To overcome such limitation, in this paper the authors propose an experimental benchmark case for CFD results validation, describing detailed flow field in correspondence of one pair of blades of the innovative Darrieus-type VAWT in static conditions. Measurements were performed employing Particle Image Velocimetry (PIV) technique on a scaled model of the turbine blades realized by 3D printing. An uncertainty analysis was also performed which showed a high accuracy of the obtained experimental results. The measurements of the main flow characteristics (bi-dimensional velocity components) were then used for a test case CFD validation of two different turbulence model

Can New Ultrasound Imaging Techniques Improve Breast Lesion Characterization? Prospective Comparison between Ultrasound BI-RADS and Semi-Automatic Software “SmartBreast”, Strain Elastography, and Shear Wave Elastography

Background: Ultrasound plays a crucial role in early diagnosis of breast cancer. The aim of this research is to evaluate the diagnostic performance of BI-RADS classification in comparison with new semi-automatic software Resona R9, Mindray, “SmartBreast” and strain elastography (SE), point shear wave (pSWE), and 2D shear wave (2D SWE) Elastography for breast lesion differentiation. Methods: Ninety-two breast nodules classified according to BI-RADS lexicon by an expert radiologist were evaluated by a second investigator with B-mode ultrasound, color Doppler, “SmartBreast”, and elastography. Histopathology was considered the gold standard. Results: The agreement between software and investigator was excellent in the identification of the posterior features of breast masses (Cohen’s k = 0.94), good for shape and vascular signal (Cohen’s k, respectively, of 0.6 and 0.65), poor for orientation, margins, and echo pattern (Cohen’s k, respectively, of 0.28, 0.33 and 0.48), moderate for dimensions (Lin’s correlation coefficient of 0.90, p = 0.07). SE showed a greater area under curve (AUC) than pSWE and 2D SWE (0.84, 0.64, and 0.61, respectively), with a greater specificity and a comparable sensitivity to pSWE (respectively, of 0.86 and 0.55, 0.81 and 0.84). Conclusions: SE improved the diagnostic performance of BI-RADS classification more than pSWE and 2D SWE; “SmartBreast” showed good agreement only for shape and vascularization but not for the other ultrasound features of breast lesions

Дексаметазон и SARS-CoV-2: опасная пандемия применения стероидов (Письмо в редакцию)

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Corticosteroids for Patients With Coronavirus Disease 2019 (COVID-19) With Different Disease Severity: A Meta-Analysis of Randomized Clinical Trials

Objectives: Efficacy and safety of corticosteroids in patients with 2019-nCoV (novel coronavirus 2019) infection still are debated. Because large randomized clinical trials (RCTs) and a well-conducted meta-analysis on the use of corticosteroids, focused on patients with coronavirus disease (COVID-19) in intensive care units, recently were published, a meta-analysis of RCTs on corticosteroids therapy in patients with different disease severity was performed to evaluate the effect on survival. Design: A meta-analyses of RCTs was performed. Setting: Patients admitted to hospital. Participants: Patients with coronavirus disease. Interventions: Administration of corticosteroids. Measurements and Main Results: A search was performed for RCTs of adult patients with acute hypoxemic failure related to 2019-nCoV infection who received corticosteroids versus any comparator. The primary endpoint was mortality rate. Five RCTs involving 7,692 patients were included. Overall mortality of patients treated with corticosteroids was slightly but significantly lower than mortality of controls (26% v 28%, relative risk {RR} = 0.89 [95% confidence interval {CI} 0.82-0.96], p = 0.003). The same beneficial effect was found in the subgroup of patients requiring mechanical ventilation (RR = 0.85 [95% CI 0.72-1.00], p = 0.05 number needed to treat {NNT} = 19). Remarkably, corticosteroids increased mortality in the subgroup of patients not requiring oxygen (17% v 13%, RR = 1.23 [95% CI 1.00-1.62], p = 0.05 number needed to harm {NNH} = 29). Tests for comparison between mechanically ventilated subgroups and those not requiring oxygen confirmed that treatment with corticosteroids had a statistically significant different effect on survival. Patients treated with corticosteroids had a significantly lower risk of need for mechanical ventilation. Conclusions: Corticosteroids may be considered in severe critically ill patients with COVID-19 but must be discouraged in patients not requiring oxygen therapy. Urgently, further trials are warranted before implementing this treatment worldwide

The Underrated Role of Ultrasound in Peritoneal Dialysis

Ultrasound is very effective in performing procedures and assessment of complications in peritoneal dialysis. The ultrasound examination can be applied for preoperative assessment, during the peritoneal catheter placement, for the detection and monitoring of infection, as well as for the evaluation of the catheter malfunction. Despite being not only a cost- and time-saving technique but also a bedside procedure, ultrasonography remains an underrated clinical tool in the field of peritoneal dialysis. This publication wants to explain and reinforce the clinical utility of US in PD and to expand the diagnostic equipment for the clinician

US Evaluation of Topical Hemostatic Agents in Post-Thyroidectomy

Background: the aim of this study was to describe the ultrasound appearance of topical hemostatics after thyroidectomy. Methods: we enrolled 84 patients who were undergoing thyroid surgery and were treated with two types of topical hemostats, 49 with an absorbable hemostat of oxidized regenerated cellulose (Oxitamp®) and 35 with a fibrin glue-based hemostat (Tisseel®). All patients were examined using B-mode ultrasound. Results: In 39 patients of the first group (approximately 80%), a hemostatic residue was detected and in some cases confused with a native gland residue, or with cancer recurrence in oncological patients. No residue was detected in patients in the second group. The main ultrasound characteristics of the tampon were analyzed and arranged according to predefined patterns, and suggestions to recognize it and avoid wrong diagnoses were provided. A part of the group of patients with tampon residue was re-evaluated after 6–12 months, ensuring that the swab remained for months after the maximum resorption time declared by the manufacturer. Conclusions: with equal hemostatic effectiveness, the fibrin glue pad is more favorable in the ultrasound follow-up because it creates reduced surgical outcomes. It is also important to know and recognize the ultrasound characteristics of oxidized cellulose-based hemostats in order to reduce the number of diagnostic errors and inappropriate diagnostic investigations

The underrated role of ultrasound in peritoneal dialysis

Ultrasound is very effective in performing procedures and assessment of complications in peritoneal dialysis. The ultrasound examination can be applied for preoperative assessment, during the peritoneal catheter placement, for the detection and monitoring of infection, as well as for the evaluation of the catheter malfunction. Despite being not only a cost- and time-saving technique but also a bedside procedure, ultrasonography remains an underrated clinical tool in the field of peritoneal dialysis. This publication wants to explain and reinforce the clinical utility of US in PD and to expand the diagnostic equipment for the clinician