482 research outputs found

    A general route to the synthesis of surfactant-free, solvent-dispersible ternary and quaternary chalcogenide nanocrystals

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    A general route to the synthesis of surfactant-free CuInS2 (CIS), Cu2CoSnS4 (CCTS) and Cu2ZnSnS4 (CZTS) nanocrystals dispersible in low boiling point solvents is proposed. These nanocrystal inks should be of great interest to the fabrication of thin film absorbers of chalcogenide solar cells

    Effects of the nature of the doping salt and of the thermal pre-treatment and sintering temperature on spark plasma sintering of transparent alumina

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    A slurry of a-Al2O3 was doped with Mg, Zr and La nitrates or chlorides, in various amounts in the range 150-500 wt ppm and then freeze-dried to produce nanosized doped powder (~150 nm). The powder was sintered by SPS to yield transparent polycrystalline alpha alumina. The influence of the nature of the doping element and the starting salt, the thermal treatment before sintering and the sintering emperature on the transparency of the ceramics were investigated. The transparency of the ceramics of nanosized Al2O3 was shown to depend mainly on the way the powder was prepared, the nature of the doping salt also had an effect. Finally, a high real inline transmittance, reaching 48.1% was achieved after optimization

    Challenges Associated with Tyrosine Kinase Inhibitor Therapy for Metastatic Thyroid Cancer

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    Tyrosine kinase inhibitors (TKIs) which target angiogenesis are promising treatments for patients with metastatic medullary and differentiated thyroid cancers. Sorafenib, sunitinib, and pazopanib are commercially available drugs which have been studied in these diseases. Vandetanib is the first drug approved in the United States for treatment of medullary thyroid cancer. These TKIs are used as chronic therapies, and therefore it is imperative to understand the adverse event profile in order to avoid excessive toxicity and maintain patients on therapy as long as it proves beneficial. Here we review common toxicities, management of these, and other challenging situations that arise when using TKIs in patients with thyroid cancer

    Structural characterization of dense reduced BaTiO3 and Ba0.95La0.05TiO3 nanoceramics showing colossal dielectric values

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    BaTiO3−x and Ba0.95La0.05TiO3−x nanoceramics showing colossal permittivity values have been characterized. While starting powders are of cubic symmetry, X-ray and Neutron Diffraction techniques and Raman Spectroscopy measurements show that the one-step processed ceramics obtained by Spark Plasma Sintering (SPS) contain cubic and tetragonal phases. Rather large oxygen deficiency determined in such ceramics by Electron Micro Probe analysis and Electron Energy Loss Spectroscopy analyzes is explained by the presence of Ti3+, as evidenced by X-ray Photoelectron Spectroscopy measurements. Transmission Electron Microscopy and High Resolution Transmission Electron Microscopy show that these ceramics contain 50–300 nm grains, which have single-domains, while grain boundaries are of nanometer scale. Colossal permittivity values measured in our dense nanoceramics are explained by a charge hopping mechanism and an interfacial polarization of a large number of polarons generated after sample reduction in SPS apparatus

    Commande linéarisée et mesure intégrée de la température dans un composite actif

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    Les travaux présentés dans cette publication concernent le développement du contrôle du composite intelligent M3C (composite qui se déforme grâce à une variation de température obtenue par effet joule via des fibres de carbone intégrées). Nous présentons plus particulièrement la linéarisation de la commande et la mesure de température. La linéarisation est obtenue par une alimentation en tension modulée en largeur d'impulsion. La mesure de température découle de la mesure de variation de résistance électrique du composite (loi de Matthiessen)

    Impact of Cardiac Computed Tomographic Angiography Findings on Planning of Cancer Therapy in Patients with Concomitant Structural Heart Disease

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    Background. Exclusion of underlying coronary artery disease (CAD) is essential in the diagnosis of chemotherapy-induced cardiomyopathy. Presence and severity of CAD can also impact the choice of therapy in cancer patients. The value of cardiac computed tomographic angiography (CCTA) in this setting has not been reported. Methods. We collected data on the clinical presentation and indications for CCTA performed from January to December 2008 at the University of Texas MD Anderson Cancer Center (MDACC). All examinations were performed using a 64-detector scanner. CCTA results and subsequent treatment decisions were examined. Results. A total of 80 patients underwent CCTA during the study period for the following indications (not mutually exclusive): cardiomyopathy of unknown etiology in 33 pts (41.3%), chest pain in 32 (40.0%), abnormal stress test in 16 (20.0%), abnormal cardiac markers in 8 (10.0%), suspected cardiac mass or thrombus in 7 (8.8%). Chemotherapy-induced cardiomyopathy was diagnosed in 18 pts (22.5%). Severe CAD was detected in 22 pts (27.5%); due to concomitant advanced cancer or patient refusal, only 12 underwent coronary angiogram. Of these, 4 pts (5% of total) underwent coronary artery bypass grafting. A total of 41 pts (51.3%) had their cancer management altered based on CCTA findings. Conclusion. CCTA is useful in evaluating cancer pts with structural heart disease and can have an impact on the management of cancer and cardiac disease

    Synthesis of CuInS2 nanometric powder by reaction in molten KSCN

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    CuInS2 was synthesized, with a yield of 70% by reaction in molten KSCN at 400 °C of CuCl2 and InCl3 with a ratio KSCN/Cu=15. The homogeneous powder obtained is constituted of nano-sized grains (70–100 nm), with a specific surface area of 6 m2/g and a band gap Eg of 1.5 eV
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