157 research outputs found

    Effect of heat treatment with CdCl2 on the electrodeposited CdTe/CdS heterojunction

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    CdS/CdTe heterojunction was subjected to chemical treatment commonly used in photovoltaic device fabrication to determine the resulting microscopic effect on the morphology and structure. CdS and CdTe thin films were electrodeposited successively onto indium tin oxide (ITO) from aqueous solution. Containing CdCl2 and Na2S2O3 for the deposition of thin film windows, the ITO/CdS resulting substrates was then used for the deposition of CdTe thin film absorber using aqueous solution of CdSO4 and TeO2. Next CdCl2 dip followed by 400°C heat treatment was used to modify the CdTe/CdS surface and interface. Scanning electron microscopy (SEM) and Atomic force microscopy (AFM) were used to evaluate the resulting surface morphology. X-ray diffraction analysis reveals that the heat treatment enhances the recrystallisation and shifts the CdTe peaks towards a smaller lattice parameter.CdS/CdTe heterojunction was subjected to chemical treatment commonly used in photovoltaic device fabrication to determine the resulting microscopic effect on the morphology and structure. CdS and CdTe thin films were electrodeposited successively onto indium tin oxide (ITO) from aqueous solution. Containing CdCl2 and Na2S2O3 for the deposition of thin film windows, the ITO/CdS resulting substrates was then used for the deposition of CdTe thin film absorber using aqueous solution of CdSO4 and TeO2. Next CdCl2 dip followed by 400°C heat treatment was used to modify the CdTe/CdS surface and interface. Scanning electron microscopy (SEM) and Atomic force microscopy (AFM) were used to evaluate the resulting surface morphology. X-ray diffraction analysis reveals that the heat treatment enhances the recrystallisation and shifts the CdTe peaks towards a smaller lattice parameter

    Physical properties of CdSexTe1-x thin films prepared by electrodeposition

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    The cadmium chalcogenides CdSexTe1-x (0≤x ≤1 ) thin films have been electrodeposited onto ITO coated glass substrates from an acid sulphate solution at 90 °C. The structure, the composition and the morphology have been studied as a function of the x coefficient by XRD, EDAX, optical absorbance and AFM techniques. All deposits have a cubic structure with a preferred orientation along the (111) direction. The composition in the films is found to vary linearly with the composition in the solution. The increase of the amount of tellurium in the CdSexTe1-x films decreases the band gap down to 1.35 eV and increases the lattice constant. The photoelectrochemical studies in a polysulfide electrolyte show that CdSexTe1-x thin films behave as n-type semiconductors.The cadmium chalcogenides CdSexTe1-x (0≤x ≤1 ) thin films have been electrodeposited onto ITO coated glass substrates from an acid sulphate solution at 90 °C. The structure, the composition and the morphology have been studied as a function of the x coefficient by XRD, EDAX, optical absorbance and AFM techniques. All deposits have a cubic structure with a preferred orientation along the (111) direction. The composition in the films is found to vary linearly with the composition in the solution. The increase of the amount of tellurium in the CdSexTe1-x films decreases the band gap down to 1.35 eV and increases the lattice constant. The photoelectrochemical studies in a polysulfide electrolyte show that CdSexTe1-x thin films behave as n-type semiconductors

    Idiopathic Membranous Nephropathy Preceding the Onset of Rheumatoid Arthritis: a Case Report

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    Introduction: Membranous nephropathy (MN) in the context of rheumatoid arthritis (RA), is often an iatrogenic complication due to the nephrotoxic effects of antirheumatic drugs. Rare cases of non-iatrogenic association between these two diseases were reported in the literature.Case report: A 30-year-old female patient presented in September 2005 with nephrotic syndrome. Renal biopsy showed features consistent with MN. Search for etiology was negative, particularly lupus serology which remained negative throughout the course of her illness. Accordingly, she was diagnosed as a case of idiopathic MN. Initially, she was treated with angiotensin converting enzyme inhibitors and angiotensin receptor blockers which maintained her protein excretion below nephrotic range for two years. Her nephrotic syndrome then relapsed and was treated with steroids and chlorambucil, according to the Ponticelli protocol. A few months later, she presented with early morning joint stiffness, polyarthritis involving the small joints of the hands, and strongly positive rheumatoid factor, fulfilling the diagnostic criteria of rheumatoid arthritis (RA). Her serum creatinine remained normal and a second renal biopsy revealed the same features of MN. Her RA was treated with pulsed methylprednisolone followed by oral steroids and methotrexate resulting in remission of the joints disease and the nephrotic syndrome. Remission was maintained for the last two years up to the time of this report.Conclusion: We hereby report a case of secondary membranous nephropathy that preceded the onset of rheumatoid arthritis by three years.Keywords: Auto-immunity; Membranous nephropathy; Rheumatoid arthriti

    Aortic valve replacement with the minimal extracorporeal circulation (Jostra MECC System) versus standard cardiopulmonary bypass: A randomized prospective trial

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    AbstractBackgroundWe prospectively evaluated a newly introduced minimal extracorporeal circulation system (Jostra MECC System; Jostra AG, Hirrlingen, Germany) for aortic valve surgery.MethodIn a prospective, randomized study, 100 patients underwent aortic valve replacement either with standard cardiopulmonary bypass (n = 50, group B) or with the MECC System (n = 50, group B). The myocardial protection and the left vent were identical for the two groups. The intrapericardial suction device was never used (only the cell salvage device was used) to reduce the air-blood contact area.ResultsNo significant differences were noted in patient characteristics and operative data between groups. Operative mortality (<30 days) was 2% for group A and 4% for group B (difference not significant). From the preoperative period to the postoperative period, the increase in C-reactive protein was significantly higher for group B (P < .001). The postoperative troponin I level was significantly lower in group A (mean 4.65 ± 2.9 μg/L at 24 hours) than in group B (8.2 ± 4.4 μg/L, P < .03). On the other hand, the MECC System was associated with platelet preservation. Renal function was better preserved and the neurologic event rate was significantly lower for the MECC group (P < .02).ConclusionThe MECC System is safe and allows aortic valve replacement under the most favorable conditions. The system is more biocompatible than standard cardiopulmonary bypass and provides a good postoperative biologic profile and good clinical results, particularly for high-risk patients

    Crumpling a Thin Sheet

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    Crumpled sheets have a surprisingly large resistance to further compression. We have studied the crumpling of thin sheets of Mylar under different loading conditions. When placed under a fixed compressive force, the size of a crumpled material decreases logarithmically in time for periods up to three weeks. We also find hysteretic behavior when measuring the compression as a function of applied force. By using a pre-treating protocol, we control this hysteresis and find reproducible scaling behavior for the size of the crumpled material as a function of the applied force.Comment: revtex 4 pages, 6 eps figures submitted to Phys Rev. let

    Association myélome multiple – maladie de Kaposi: à propos d’un cas

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    L'association Kaposi–myélome multiple est extrêmement rare. Nous rapportons, le cas d'un patient âgé de 76 ans suivi dans notre formation pour un myélome à immunoglobuline A kappa stade III-B selon Durie et Salmon. Ceci a été associé à des lésions cutanées dont la biopsie cutanée était en faveur d’une maladie de Kaposi. La sérologie de l’herpès virus humain de type 8 (HHV8) est revenue positive. Une radiothérapie sur les lésions était refusée par le patient. L'évolution était marquée par une altération de l'état général. Le patient ayant refusé la radiothérapie et toute prise en charge thérapeutique est décédée deux mois plus tard. Nous rapportons, à notre connaissance, le 18ème cas mondial de maladie de Kaposi associée à un Kahler chez un patient HHV8 positif. C'est une association exceptionnelle rendant probable le rôle pathogénique de HHV8 dans le développement du myélome

    Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

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    Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries
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