Aortic corset syndrome

The majority of proximal anastomotic complications of aortofemoral bypass grafts are related to the formation of pseudoaneurysms or true proximal aneurysmal dilation of the residual infrarenal aorta. The late development of occlusive disease at the proximal anastomosis is an extremely rare event. We report two patients in whom symptomatic stenoses developed involving the proximal anastomoses of aortofemoral bypass grafts originally placed for aortoiliac occlusive disease. Surgical exploration demonstrated the presence of a constricting prosthetic corset wrapped around the proximal suture line of each graft. Exuberant neointimal hyperplasia was responsible for both stenoses.     

Effect of Ratio of Surface Area to Volume on Oxygen Self-Diffusion Coefficients Determined for Crushed MgO-Al2O3 Spinels

Oxygen self-diffusion coefficients for single-crystal MgO-Al₂O₃ spinels previously determined for crushed particles were recalculated using the microscopic suface area of the sample, as was done for alumina. The corrected results agree well with those of Reddy and Cooper .     

Effects of Na2SiO3 on anodization of Mg-Al-Zn alloy in 3 M KOH solution

The anodic behavior of Mg-Al-Zn alloy (AZ91D) under low potential electrolysis in 3 M KOH solutions was studied with and without addition of 0.5-5 M Na₂SiO₃. Anodic films incorporating silicon were formed during electrolysis, and the films formed under constant potential electrolysis at 4 V in 3 M KOH solution with Na₂SiO₃ were uniform and thicker than the films formed without Na₂SiO₃. A few at% of silicon was present as Mg₂SiO₄ in the films, although the main compound was Mg(OH)₂. The corrosion resistance of the films formed in solutions with Na₂SiO₃ increased in an anodic polarization test in 0.1 M KCl solution.     

Eddy current analysis of thin metal container in induction heating by line integral equations

In recent years, induction‐heating cookers have spread rapidly. It is desirable to commercialize flexible and disposable food containers that are suitable for induction heating. In order to develop a good‐quality food container for moderate heating, the eddy currents induced in a thin metal plate must be accurately analyzed. The integral equation method is widely used for solving induction‐heating problems. If the plate thickness approaches zero, the surface integral equations on the upper and lower plate surfaces tend to become the same and the equations become ill‐conditioned. In this paper, we first derive line integral equations from the boundary integral equations under the assumption that the electromagnetic fields in the metal are attenuated more rapidly than those along the metal surface. Next, to test the validity of the line integral equations, we solve for the eddy current induced in a thin metal container in induction heating and obtain the power density imparted to the container and the impedance characteristics of the heating coil. We then compare the computed results with those obtained by the FEM. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 168(2): 20–27, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20813     

Quantitative determination of domperidone in rat plasma by high-performance liquid chromatography with fluorescence detection

A sensitive and selective analytical method for the determination of domperidone in rat plasma is described. The procedure involves liquid-liquid extraction followed by reversed-phase high-performance chromatographic analysis with fluorometric detection at 282 nm for excitation and 328 nm for emission. The detection limit was 1 ng ml(-1) using 1 ml of plasma. This assay procedure should be useful for the pharmacokinetic study of domperidone in small animals such as rats.     

Trajectory-based design of robust non-fragile controllers for a class of uncertain linear continuous-time systems

This paper deals with a design problem of robust non-fragile stabilizing controllers for a class of uncertain linear continuous-time systems. The proposed design approach of robust non-fragile controllers is based on computation of the trajectory for the uncertain linear system and differs from the existing methods based on quadratic stabilization via Lyapunov criterion. In this paper, we show that sufficient conditions for asymptotical stability of the linear system with uncertainties and controller gain variations, and a LMI-based design algorithm of a robust non-fragile controller. Furthermore, we extend the result to the design problem of decentralized robust non-fragile controllers for a class of uncertain large-scale interconnected systems. Finally, the effectiveness of the proposed design scheme of robust non-fragile controllers is shown through illustrative examples.     

Formation of Alkoxy-Derived lead Niobates in the PbO-Rich Region

The formation of lead niobates in the PbO-rich region is studied using powders prepared by the simultaneous hydrolysis of lead and niobium alkoxides. Cubic 3PbO·2Nb_2PO₅ solid solutions crystallize at low temperatures from amorphous materials having concentrations of 58 to 75 mol% PbO. The lattice parameter a increases linearly from 1.0544 to 1.0708 nm with increasing PbO. At higher temperatures the solid solutions made with 66.67 and 71.43 mol% PbO transform into 2PbO·Nb₂O₅ (monoclinic) and 5PbO·2Nb₂O_s (monoclinic), respectively. Monoclinic 5PbO·2Nb₂O₅ transforms into a new modification at = 3850° to = 3900°C. It has a rhombohedral unit cell with a = 0.7461 nm and c = 4.8092 nm ( a = 1.6599 nm, a = 25.97°). In the presence of excess lead, monoclinic 5PbO·2Nb₂O₅ transforms into tetragonal 3PbO·Nb₂O₅.     

An experimental and numerical study on the forward biased SOA ofIGBTs

Thermal and electrical destructions of n-ch 600 V punchthrough type IGBTs in F.B.SOA are investigated by experiments and simulations, The cause of the thermal destruction is the thermal disappearance of built-in potential of p-n junction between the n⁺ emitter and the p base of the IGBT integral DMOSFET occurring at the critical temperature of ~650 K. Experiment and simulation results for the critical temperature show a good agreement. The cause of the electrical destruction is impact ionization at the n^- drift/n⁺ buffer junction in addition to the n^- drift/p base junctions. That triggers a positive feedback mechanism of increasing IGBT integral pnp transistor current which causes the device to lose gate controllability. The experimentally obtained critical power dissipation is ~2000 kW/cm². This value is ten times greater than BJTs. It was also found that emitter ballast resistance (EBR) plays an important role in describing the F.B.SOA of IGBTs