Multiphysics simulation of corona discharge induced ionic wind

Ionic wind devices or electrostatic fluid accelerators are becoming of increasing interest as tools for thermal management, in particular for semiconductor devices. In this work, we present a numerical model for predicting the performance of such devices, whose main benefit is the ability to accurately predict the amount of charge injected at the corona electrode. Our multiphysics numerical model consists of a highly nonlinear strongly coupled set of PDEs including the Navier-Stokes equations for fluid flow, Poisson's equation for electrostatic potential, charge continuity and heat transfer equations. To solve this system we employ a staggered solution algorithm that generalizes Gummel's algorithm for charge transport in semiconductors. Predictions of our simulations are validated by comparison with experimental measurements and are shown to closely match. Finally, our simulation tool is used to estimate the effectiveness of the design of an electrohydrodynamic cooling apparatus for power electronics applications.Comment: 24 pages, 17 figure

Segmentation of Histological Images using a Metaheuristic-based Level Set Approach

This paper presents a two-phase method to segment the hippocampus in histological images. The first phase represents a training stage where, from a training set of manually labelled images, the hippocampus representative shape and texture are derived. The second one, the proper segmentation, uses a metaheuristic to evolve the contour of a geometric deformable model using region and texture information. Three different metaheuristics (real-coded GA, Particle Swarm Optimization and Dierential Evolution) and two classical segmentation algorithms (Chan & Vese model and Geodesic Active Contours) were compared over a test set of 10 histological images. The best results were attained by the real-coded GA, achieving an average and median Dice Coefficient of 0.72 and 0.77, respectively

Tumour-induced osteomalacia: A case report of craniofacial localization

Tumour-induced osteomalacia (TIO) is a rare paraneoplastic syndrome. It is caused by a variety of small, slow-growing mesenchymal tumors (phosphaturic mesenchymal tumour, PMT) that can produce fibroblast growth factor 23 (FGF23). FGF23, through its effect on the renal reabsorption of phosphates, causes marked phosphaturia and hypophosphatemia which, if persistent, cause bone demineralization.The vague and non-specific symptomatology (diffuse musculoskeletal pains, asthenia and frequent fractures) often makes diagnosis difficult and therefore delays treatment.Typically TIO are single tumors of mesenchymal origins which behave benignly, while the malignant histological variants are very rare. Furthermore, they favour soft tissues, and cranio-facial localization occurs in only 10–15% of cases.We report a case of TIO located in the left pterygopalatine fossa. The patient was a 68-year-old man who had been suffering from diffuse osteomuscular pain and frequent bone fractures for about two years. Biochemical testing showed elevated levels of phosphates and of 1,25 dihydroxyvitamin D, an increase in alkaline phosphatase, and hyperphosphaturia.Gallio-DOTA-octreotate somatostatin receptor positron emission tomography/computed tomography (DOTATATE PET/TC) demonstrated uptake in the left nasal sinus area. Computed tomography (CT) and magnetic resonance imaging (MRI) revealed a left pterygopalatine fossa mass. The patient underwent surgical resection of the mass, and the histology was consistent with a mesenchymal tumour. His serum phosphate levels normalized in about 3 months after surgery, and his hip pain had resolved completely in 6–8 months. Our case highlights the importance of recognizing this disease to avoid severe disability for patients. Keywords: Tumour-induced osteomalacia, Hypophosphatemia, Fibroblast growth factor 23, Paraneoplastic disorder, Alkaline phosphatas

Does age influence the success of intra-tympanic steroid treatment in idiopathic sudden deafness?

The present study shows that AGE, DELAY, and PTA_PRE may be considered factors influencing therapeutic success in intra-tympanic steroid therapy

The role of imaging in the evaluation of joint involvement in 102 consecutive patients with systemic lupus erythematosus

Objective: To assess the prevalence of joint involvement in consecutive patients with systemic lupus erythematosus (SLE) by means of clinical assessment, joint US and MRI and to evaluate the sensitivity and specificity of physician evaluation of joint involvement. Methods: At enrolment, patients underwent a complete physical examination including a 44-joint count, and hand deformities were scored. On the day of enrolment, each patient underwent a non-dominant hand-wrist ultrasound (US) examination and a non-dominant hand-wrist MRI study without contrast injection. Results: One hundred and two patients (F 95, M 7) were enrolled. By physician examination hand or wrist involvement was diagnosed in 23.5%. At least one pathological finding was revealed by US examination at wrist and/or hand joints in 55%. We found a low sensitivity (46.5%) with high specificity (93.2%) of the physician assessment for the evaluation of joint involvement.The MRI imaging showed at least one erosion in 47.3% patients at the hand and in 98.9% at the wrist; in healthy subjects erosions were found in 19.6% and 97.8% at the hand and wrist, respectively. Conclusions: In conclusion, (i) physicians tend to underestimate the severity of joint involvement in SLE; (ii) US assessment shows a high prevalence of joint and tendon involvement; and (iii) the MRI evaluation shows a high prevalence of damage, suggesting that joint involvement in SLE could be more severe than expected