1,426 research outputs found

    Thermodynamic assessment of the variation of the surface areas of two synthetic swelling clays during adsorption of water

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    International audienceTwo synthetic smectites (montmorillonite and beidellite) are studied by a water adsorption technique in order to assess their specific surface areas under atmospheric conditions. A route recently proposed for extracting the thermodynamic data from experimental adsorption isotherms is used. The variation of the specific surface area during water adsorption is obtained, which can be linked to the enlargement of the interlayer space determined using X-ray diffraction. This variation is compared to an idealized specific surface area obtained from TEM and X-ray measurements in agreement with crystallographic models. All these results are also compared with those obtained previously for a natural montmorillonite. A simple view of swelling is proposed

    Fractoluminescence characterization of the energy dissipated during fast fracture of glass

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    Fractoluminescence experiments are performed on two kinds of silicate glasses. All the light spectra collected during dynamic fracture reveal a black body radiator behaviour, which is interpreted as a crack velocity-dependent temperature rise close to the crack tip. Crack velocities are estimated to be of the order of 1300 m.s−1^{-1} and fracture process zones are shown to extend over a few nanometers.Comment: Accepted for publication in Europhysics Letters; 5 pages; 4 figure

    “Angular resolution expected from iCHORD orientation maps through a revisited ion channeling model”

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    International audienceCrystalline orientation maps are obtained in a Focused Ion Beam (FIB) microscope using the ion CHanneling ORientation Determination (iCHORD) method, which relies on the channeling phenomenon observed in ion-induced secondary electron images. The current paper focuses on the angular resolution that can be expected from such orientation maps, obtained using a revisited ion channeling model. A specific procedure was developed to evaluate the angular resolution, based on the distribution of orientation errors when evaluating controlled sample disorientation. The main advantage is that no external reference is required. An angular resolution of 1° is obtained on a nickel based sample using standard acquisition conditions. This value fulfills most of the needs in terms of microstructural characterization usually carried out by Electron Back Scattered Diffraction

    Modeling the series of (n x 2) Si-rich reconstructions of beta-SiC(001): a prospective atomic wire?

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    We perform ab initio plane wave supercell density functional calculations on three candidate models of the (3 x 2) reconstruction of the beta-SiC(001) surface. We find that the two-adlayer asymmetric-dimer model (TAADM) is unambiguously favored for all reasonable values of Si chemical potential. We then use structures derived from the TAADM parent to model the silicon lines that are observed when the (3 x 2) reconstruction is annealed (the (n x 2) series of reconstructions), using a tight-binding method. We find that as we increase n, and so separate the lines, a structural transition occurs in which the top addimer of the line flattens. We also find that associated with the separation of the lines is a large decrease in the HOMO-LUMO gap, and that the HOMO state becomes quasi-one-dimensional. These properties are qualititatively and quantitatively different from the electronic properties of the original (3 x 2) reconstruction.Comment: 22 pages, including 6 EPS figure

    Prioritising systemic cancer therapies applying ESMO's tools and other resources to assist in improving cancer care globally:the Kazakh experience

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    BACKGROUND: In Kazakhstan, cancer is the second leading cause of death with a major public health and economic burden. In the last decade, cancer care and cancer medicine costs have significantly increased. To improve the efficiency and efficacy of cancer care expenditure and planning, the Kazakhstan Ministry of Health requested assistance from the World Health Organization (WHO) and the European Society for Medical Oncology (ESMO) to review its systemic cancer treatment protocols and essential medicines list and identify high-impact, effective regimens. MATERIALS AND METHODS: ESMO developed a four-phase approach to review Kazakhstan cancer treatment protocols: (i) perform a systematic analysis of the country’s cancer medicines and treatment protocols; (ii) cross-reference the country’s cancer protocols with the WHO Model List of Essential Medicines, the ESMO-Magnitude of Clinical Benefit Scale and the European Medicines Agency’s medicine availability and indications database; (iii) extract treatment recommendations from the ESMO Clinical Practice Guidelines; (iv) expert review for all cancer medicines not on the WHO Model List of Essential Medicines and the country treatment protocols. RESULTS: This ESMO four-phase approach led to the update of the Kazakhstan national essential cancer medicines list and the list of cancer treatment protocols. This review has led to the withdrawal of several low-value or non-evidence-based medicines and a budget increase for cancer care to include all essential and highly effective medicines and treatment options. CONCLUSION: When applied effectively, this four-phase approach can improve access to medicines, efficiency of expenditure and sustainability of cancer systems. The WHO–ESMO collaboration illustrated how, by sharing best practices, tools and resources, we can address access to cancer medicines and positively impact patient care
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