Endovascular Treatment of Popliteal Artery Aneurysms

AbstractObjective. To present the results of the endovascular treatment of popliteal artery aneurysms.Methods. From April 1999 to January 2002, 11 patients, aged 40–94 years, with 12 popliteal aneurysms were treated. Nine (75%) underwent an endoluminal repair, of whom three were done emergently due to a aneurysm rupture. Aneurysm diameter was 28–105 (mean 69) mm. A Hemobahn stent graft was inserted in six, Wallgraft in two and Passager in one case.Results. During a mean follow-up of 14 (3–31) months, four (44%) thromboses occurred: two in the early postoperative period (30 days) and two during the late postoperative period. Two of the four occluded grafts were successfully reopened, and in the one a stenosis of the distal end of the stent graft was treated with balloon dilatation. Patency rates at 1 and 12 months were 64/47% (primary patency) and 88/75% (secondary patency), respectively.Conclusion. Initial experience with endovascular treatment of the popliteal aneurysm in high-risk patients yielded modest results. Larger number of patients and further follow-up time is necessary to evaluate the long-term results

Simulation Analysis of Air Flow and Turbulence Statistics in a Rib Grit Roughened Duct

The implementation of variable artificial roughness patterns on a surface is an effective technique to enhance the rate of heat transfer to fluid flow in the ducts of solar air heaters. Different geometries of roughness elements investigated have demonstrated the pivotal role that vortices and associated turbulence have on the heat transfer characteristics of solar air heater ducts by increasing the convective heat transfer coefficient. In this paper we investigate the two-dimensional, turbulent, unsteady flow around rectangular ribs of variable aspect ratios by directly solving the transient Navier-Stokes and continuity equations using the finite elements method. Flow characteristics and several aspects of turbulent flow are presented and discussed including velocity components and statistics of turbulence. The results reveal the impact that different rib lengths have on the computed mean quantities and turbulence statistics of the flow. The computed turbulence parameters show a clear tendency to diminish downstream with increasing rib length. Furthermore, the applied numerical method is capable of capturing small-scale flow structures resulting from the direct solution of Navier-Stokes and continuity equations

Inflammatory pseudotumor of the liver: a case report and review of the literature

<p>Abstract</p> <p>Introduction</p> <p>Inflammatory pseudotumor of the liver represents a fairly uncommon pathology. Although it is a benign tumor, the correct diagnosis can be missed.</p> <p>Case presentation</p> <p>We report the case of a 55-year-old Caucasian man, who presented with a one-month history of abdominal pain and weight loss. He was diagnosed with a primary liver tumor by computed tomography and magnetic resonance imaging. Alpha-fetoprotein levels ranged within normal limits. A right posterior sectorectomy was performed. Histopathology revealed an inflammatory pseudotumor of the liver. Our patient remains in good condition one year later.</p> <p>Conclusion</p> <p>Although inflammatory pseudotumor of the liver is usually a benign process, controversy regarding its management still exists. With this case report we review the existing literature and consider hepatectomy as a safe treatment approach.</p

Cellular Automata Applications in Shortest Path Problem

Cellular Automata (CAs) are computational models that can capture the essential features of systems in which global behavior emerges from the collective effect of simple components, which interact locally. During the last decades, CAs have been extensively used for mimicking several natural processes and systems to find fine solutions in many complex hard to solve computer science and engineering problems. Among them, the shortest path problem is one of the most pronounced and highly studied problems that scientists have been trying to tackle by using a plethora of methodologies and even unconventional approaches. The proposed solutions are mainly justified by their ability to provide a correct solution in a better time complexity than the renowned Dijkstra's algorithm. Although there is a wide variety regarding the algorithmic complexity of the algorithms suggested, spanning from simplistic graph traversal algorithms to complex nature inspired and bio-mimicking algorithms, in this chapter we focus on the successful application of CAs to shortest path problem as found in various diverse disciplines like computer science, swarm robotics, computer networks, decision science and biomimicking of biological organisms' behaviour. In particular, an introduction on the first CA-based algorithm tackling the shortest path problem is provided in detail. After the short presentation of shortest path algorithms arriving from the relaxization of the CAs principles, the application of the CA-based shortest path definition on the coordinated motion of swarm robotics is also introduced. Moreover, the CA based application of shortest path finding in computer networks is presented in brief. Finally, a CA that models exactly the behavior of a biological organism, namely the Physarum's behavior, finding the minimum-length path between two points in a labyrinth is given.Comment: To appear in the book: Adamatzky, A (Ed.) Shortest path solvers. From software to wetware. Springer, 201

A digital memristor emulator for FPGA-based artificial neural networks

FPGAs are reconfigurable electronic platforms, well-suited to implement complex artificial neural networks (ANNs). To this end, the compact hardware (HW) implementation of artificial synapses is an important step to obtain human brain-like functionalities at circuit-level. In this context, the memristor has been proposed as the electronic analogue of biological synapses, but the price of commercially available samples still remains high, hence motivating the development of HW emulators. In this work we present the first digital memristor emulator based upon a voltagecontrolled threshold-type bipolar memristor model. We validate its functionality in low-cost yet powerful FPGA families. We test its suitability for complex memristive circuits and prove its synaptic properties in a small associative memory via a perceptron ANN.Peer ReviewedPostprint (published version

The Influence of Water Nitrate Concentration Combined with Elevated Temperature on Rainbow Trout <i>Oncorhynchus mykiss</i> in an Experimental Aquaponic Setup

Intensive recirculating systems are a fast-developing sector of aquaculture. While several warm-water fish have been reared in aquaponics, almost no data are available for cold-water species. The determination of nitrate toxicity thresholds in recirculating aquaculture is crucial. Different pollutants are typically more toxic at elevated temperatures. We investigated the performance of Oncorhynchus mykiss under two different nitrate levels and two temperatures. We applied a 2 × 2 factorial design, where fish (9.78 ± 0.51 g) were exposed to nitrate concentrations of 40 or 110 mg/L NO3− and to temperatures of 17 °C or 21 °C for 20 days. This study focused on understanding the physiological responses of rainbow trout to relatively low nitrate levels under heat stress in order to investigate the feasibility of integrating this species into commercial aquaponics. The growth, condition, and expression of genes involved in metabolism, heat shock, antioxidant, and immune response were assessed in the liver, together with the activities of enzymes related to glucose and fatty acid metabolism. High nitrate levels at 17 °C affected the condition but did not alter growth, leading to increased glycolytic potential and, occasionally, a greater reliance on lipid oxidation. Antioxidant defense was mainly induced due to high nitrates and the similar expression patterns of antioxidant genes observed under high nitrate at both 17 °C and 21 °C. Warm exposure decreased condition and growth, leading to greatly reduced glucokinase transcription, irrespective of the nitrate levels. Exposure to 21 °C and high nitrate led to equivalent growth and condition as well as to a milder inflammatory response combined with metabolic readjustments (enhancement of glycolytic and lipid oxidation pathways) compared to the low nitrates at 21 °C. Based on the results, rearing at a temperature close to 21 °C should be avoided for fingerling growth, while NO3− concentration until 110 mg/L may not have severe impacts on fingerling health and growth at 17 °C. In addition, rainbow trout fingerlings can tolerate a 20-day exposure at 21 °C and NO3− up to 110 mg/L. Additional factors should always be considered, such as specific water quality parameters, for a comprehensive approach to assessing the feasibility of rainbow trout aquaculture in aquaponics

A digital memristor emulator for FPGA-based artificial neural networks

FPGAs are reconfigurable electronic platforms, well-suited to implement complex artificial neural networks (ANNs). To this end, the compact hardware (HW) implementation of artificial synapses is an important step to obtain human brain-like functionalities at circuit-level. In this context, the memristor has been proposed as the electronic analogue of biological synapses, but the price of commercially available samples still remains high, hence motivating the development of HW emulators. In this work we present the first digital memristor emulator based upon a voltagecontrolled threshold-type bipolar memristor model. We validate its functionality in low-cost yet powerful FPGA families. We test its suitability for complex memristive circuits and prove its synaptic properties in a small associative memory via a perceptron ANN.Peer Reviewe