EXAFS Study of Rutile and Anatase

Two crystallographic forms of TiO2 (rutile and anatase) were subject to an extended x-ray absorption fine structure study at the K threshold of titanium. Data analysis was carried out by Fourier methods and curve fitting techniques. Using the theoretical phases, Ti-O bond distances of 1.93(1) Å were derived both for rutile and anatase, as compared to the crystallographic values of 1.948 - 1.980(1) Å (rutile) and 1.934-1.980(1) Å (anatase). The ratio of the cation coordination numbers Nr/Na = 1.07 is close to the theoretical value

Two-year clinical follow-up of the Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in The Netherlands (MR CLEAN): Design and statistical analysis plan of the extended follow-up study

Background: MR CLEAN was the first randomized trial to demonstrate the short-term clinical effectiveness of endovascular treatment in patients with acute ischemic stroke caused by large vessel occlusion in the anterior circulation. Several other trials confirmed that endovascular treatment improves clinical outcome at three months. However, limited data are available on long-term clinical outcome. We aimed to estimate the effect of endovascular treatment on functional outcome at two-year follow-up in patients with acute ischemic stroke. Secondly, we aimed to assess the effect of endovascular treatment on major vascular events and mortality during two years of follow-up. Methods: MR CLEAN is a multicenter clinical trial with randomized treatment allocation, open-label treatment, and blinded endpoint evaluation. Patients included were 18 years or older with acute ischemic stroke caused by a proven anterior proximal artery occlusion who could be treated within six hours after stroke onset. The intervention contrast was endovascular treatment and usual care versus no endovascular treatment and usual care. The current study extended the follow-up duration from three months to two years. The primary outcome is the score on the modified Rankin scale at two years. Secondary outcomes include all-cause mortality and the occurrence of major vascular events within two years of follow-up. Discussion: The results of our study provide information on the long-term clinical effectiveness of endovascular treatment, which may have implications for individual treatment decisions and estimates of cost-effectiveness. Trial registration:NTR1804. Registered on 7 May 2009; ISRCTN10888758. Registered on 24 July 2012 (main MR CLEAN trial); NTR5073. Registered on 26 February 2015 (extended follow-up study)

EXAFS Study of Rutile and Anatase

Two crystallographic forms of TiO2 (rutile and anatase) were subject to an extended x-ray absorption fine structure study at the K threshold of titanium. Data analysis was carried out by Fourier methods and curve fitting techniques. Using the theoretical phases, Ti-O bond distances of 1.93(1) Å were derived both for rutile and anatase, as compared to the crystallographic values of 1.948 - 1.980(1) Å (rutile) and 1.934-1.980(1) Å (anatase). The ratio of the cation coordination numbers Nr/Na = 1.07 is close to the theoretical value

Microstructural properties and local atomic structures of cobalt oxide nanoparticles synthesised by mechanical ball-milling process

In this study, facile preparation of pure and nano-sized cobalt oxides particles was achieved using low-cost mechanical ball-milling synthesis route. Microstructural and morphological properties of synthesised products were characterised by X-ray diffraction (XRD) and transmission electron microscopy (TEM) techniques. XRD results indicated that the fabricated samples composed of cubic pure phase CoO and Co3O4 nanocrystalline particles with an average crystallite size of 37.2 and 31.8nm, respectively. TEM images showed that the resulting samples consisted of agglomerates of particles with average diameter of about 37.6nm for CoO and 31.9nm for Co3O4. Phase purity of the prepared samples was further investigated due to their promising technological applications. Local atomic structure properties of the prepared nanoparticles were probed using synchrotron radiation-based X-ray absorption spectroscopy (XAS) including X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS). EXAFS data analysis further confirmed the formation of single-phase CoO and Co3O4 nanoparticles. In addition, structural properties of cobalt oxide nanoparticles were investigated by performing density functional theory calculations at B3LYP/TZVP level and Born-Oppenheimer molecular dynamics. Theoretical calculations for both prepared samples were found to be consistent with the experimental results derived from EXAFS analysis. Obtained results herein reveals that highly crystalline and pure phase CoO and Co3O4 nanoparticles can be synthesised using simple, inexpensive and eco-friendly ball-milling method for renewable energy applications involving fuel cells and water splitting devices