Chemical composition of nanoporous layer formed by electrochemical etching of p-type GaAs

Abstract : We have performed a detailed characterization study of electrochemically etched p-type GaAs in a hydrofluoric acid-based electrolyte. The samples were investigated and characterized through cathodoluminescence (CL), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS). It was found that after electrochemical etching, the porous layer showed a major decrease in the CL intensity and a change in chemical composition and in the crystalline phase. Contrary to previous reports on p-GaAs porosification, which stated that the formed layer is composed of porous GaAs, we report evidence that the porous layer is in fact mainly constituted of porous As2O3. Finally, a qualitative model is proposed to explain the porous As2O3 layer formation on p-GaAs substrate

Nurses' perceptions of aids and obstacles to the provision of optimal end of life care in ICU

Contains fulltext : 172380.pdf (publisher's version ) (Open Access

How can we define the extracorporeal circulation quality?

Extracorporeal circulation (ECC) has to ensure homeostasis of the patient and to minimize pathophysiological disorders inherent in the technique. However, we cannot dissociate it from the surgery and anesthesia knowing that the discipline involves a close partnership with these stakeholders. The purpose of this publication is to review the essential elements that at present can contribute to the quality of the CEC and suggest improvements and developments to be implemented in this area

Successful Controlled Limb Reperfusion after Severe Prolonged Ischemia

Controlled limb reperfusion was performed in two patients who were admitted for lower limb-threatening ischemia as a result of embolism. After embolectomy, the inflow blood was drained with a cannula and mixed with a crystalloid solution to obtain an hyperosmolar, hypocalcemic, alkalotic, and substrate-enriched (aspartate, glutamate) reperfusate. This reperfusate was reinjected with a roller pump for 30 minutes through two cannulas inserted in the profunda and superficial femoral arteries. Temperature, intraarterial pressures, and flow were closely controlled. No complications occurred, and complete recovery of motor and sensory functions were observed, with restoration of pedal pulses

Electromechanical coupling in anodic niobium oxide: Electric field-induced strain, internal stress, and dielectric response

Seemingly, contradictory results have been reported so far for electrostriction in anodic oxides. Furthermore, no definitive agreement could be obtained with theory. In this paper, in situ techniques are combined to elucidate electrostriction in anodic niobium oxide. The dependence of strain, internal stress, and dielectric constant on the electric field is measured by, respectively, spectroscopic ellipsometry, curvature, and impedance measurements. The through-thickness strain is tensile and proportional to the square of the electric field. The in-plane internal stress is compressive and proportional to the square of the electric field at low field values. The internal stress is predicted relatively well by the Maxwell stress because of the weak dependence of the dielectric constant on the volume change of the oxide. The dielectric constant decreases with the electric field, the dependence being quadratic. While the evolution of the strain and stress with the electric field can be ascribed to the dependence of the dielectric constant on strain, the dependence of the dielectric constant on the electric field contains an explicit strain and electric field dependence. A mechanism for the latter is proposed. © 2012 American Institute of Physics

Levels of inflammatory markers in the blood processed by autotransfusion devices during cardiac surgery associated with cardiopulmonary bypass circuit

Intraoperative blood salvage devices allowing a reinfusion of red blood cells (RBCs) after processing of shed blood and stagnant blood in the mediastinal cavity are more and more used to reduce homologous blood requirements in cardiac surgery with cardiopulmonary bypass (CPB). As the proinflammatory activity of the shed blood also contributes to morbidity during CPB, we conducted a prospective study in order to examine the quality of autologous blood before and after processing with five different devices [BRAT2, Sequestra, Compact Advanced, Cell Saver 5 (CS5), Continuous Autologous Transfusion System (CATS)]. All systems resulted in an excellent haemoconcentration, ranging from 53.7% (Compact) to 68.9% (CATS). The concentrations and elimination rates of several inflammatory markers [IL-1beta, IL-2, IL-8, TNFalpha, myeloperoxidase (MPO), elastase] were examined. Except for the Sequestra, an important increase in concentration of IL-1beta (between 30% and 220%) has been observed after processing with each device. In contrast, the attenuation rate of IL-6 and TNFalpha (95%) was optimal for all investigated blood salvages systems. Regarding IL-8, only the CATS and CS5 systems were able to attenuate this biological parameter with an excellent efficacy. The rate of attenuation in MPO and elastase, as markers of leukocyte activation, was higher than 80% for all devices. In conclusion, the different RBC washing systems tested in this study resulted in a significant attenuation of the inflammatory response. Increased levels of IL-1beta after processing remained, however, unclear. According to the type of protocol, based on inlet haematocrit, fill and wash speeds, and wash volumes, small variations in reducing the inflammatory response have been observed from one device to another

Heart transplantation, indications and results at the University Hospital of Liege

peer reviewedHeart transplantation remains undoubtedly the most effective treatment for end-stage heart failure, whatever its cause. Last decade has witnessed significant improvements in terms of morbidity and mortality following heart transplant. The 5-year survival rate is now beyond 70 %. However, the shortage of potential donors limits its use and requires strict criteria before listing a candidate for heart transplantation. Herein, we present a review of current indications and results of the heart transplantation program at the University hospital of Liege