288 research outputs found

    Paricalcitol versus cinacalcet plus low-dose vitamin D for the treatment of secondary hyperparathyroidism in patients receiving haemodialysis: study design and baseline characteristics of the IMPACT SHPT study

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    Background. Paricalcitol and cinacalcet are common therapies for patients on haemodialysis with secondary hyperparathyroidism (SHPT). We conducted a multi-centre study in 12 countries to compare the safety and efficacy of paricalcitol and cinacalcet for the treatment of SHPT

    Controlled Growth of WO3Nanostructures with Three Different Morphologies and Their Structural, Optical, and Photodecomposition Studies

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    Tungsten trioxide (WO3) nanostructures were synthesized by hydrothermal method using sodium tungstate (Na2WO4·2H2O) alone as starting material, and sodium tungstate in presence of ferrous ammonium sulfate [(NH4)2Fe(SO4)2·6H2O] or cobalt chloride (CoCl2·6H2O) as structure-directing agents. Orthorhombic WO3having a rectangular slab-like morphology was obtained when Na2WO4·2H2O was used alone. When ferrous ammonium sulfate and cobalt chloride were added to sodium tungstate, hexagonal WO3nanowire clusters and hexagonal WO3nanorods were obtained, respectively. The crystal structure and orientation of the synthesized products were studied by X-ray diffraction (XRD), micro-Raman spectroscopy, and high-resolution transmission electron microscopy (HRTEM), and their chemical composition was analyzed by X-ray photoelectron spectroscopy (XPS). The optical properties of the synthesized products were verified by UV–Vis and photoluminescence studies. A photodegradation study on Procion Red MX 5B was also carried out, showing that the hexagonal WO3nanowire clusters had the highest photodegradation efficiency

    Manganese hexacyanomanganate open framework as a high-capacity positive electrode material for sodium-ion batteries

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    Potential applications of sodium-ion batteries in grid-scale energy storage, portable electronics and electric vehicles have revitalized research interest in these batteries. However, the performance of sodium-ion electrode materials has not been competitive with that of lithium-ion electrode materials. Here we present sodium manganese hexacyanomanganate (Na2MnII[Mn-II(CN)(6)]), an open-framework crystal structure material, as a viable positive electrode for sodium-ion batteries. We demonstrate a high discharge capacity of 209 mAh g(-1) at C/5 (40 mA g(-1)) and excellent capacity retention at high rates in a propylene carbonate electrolyte. We provide chemical and structural evidence for the unprecedented storage of 50% more sodium cations than previously thought possible during electrochemical cycling. These results represent a step forward in the development of sodium-ion batteries.open212

    An Effective Amperometric Biosensor Based on Gold Nanoelectrode Arrays

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    A sensitive amperometric biosensor based on gold nanoelectrode array (NEA) was investigated. The gold nanoelectrode array was fabricated by template-assisted electrodeposition on general electrodes, which shows an ordered well-defined 3D structure of nanowires. The sensitivity of the gold NEA to hydrogen peroxide is 37 times higher than that of the conventional electrode. The linear range of the platinum NEA toward H2O2is from 1 × 10−6to 1 × 10−2 M, covering four orders of magnitudes with detection limit of 1 × 10−7 M and a single noise ratio (S/N) of four. The enzyme electrode exhibits an excellent response performance to glucose with linear range from 1 × 10−5to 1 × 10−2 M and a fast response time within 8 s. The Michaelis–Menten constantkm and the maximum current densityimaxof the enzyme electrode were 4.97 mM and 84.60 μA cm−2, respectively. This special nanoelectrode may find potential application in other biosensors based on amperometric signals

    Bilateral effects of unilateral cerebellar lesions as detected by voxel based morphometry and diffusion imaging

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    Over the last decades, the importance of cerebellar processing for cortical functions has been acknowledged and consensus was reached on the strict functional and structural cortico-cerebellar interrelations. From an anatomical point of view strictly contralateral interconnections link the cerebellum to the cerebral cortex mainly through the middle and superior cerebellar peduncle. Diffusion MRI (dMRI) based tractography has already been applied to address cortico-cerebellar-cortical loops in healthy subjects and to detect diffusivity alteration patterns in patients with neurodegenerative pathologies of the cerebellum. In the present study we used dMRI-based tractography to determine the degree and pattern of pathological changes of cerebellar white matter microstructure in patients with focal cerebellar lesions. Diffusion imaging and high-resolution volumes were obtained in patients with left cerebellar lesions and in normal controls. Middle cerebellar peduncles and superior cerebellar peduncles were reconstructed by multi fiber diffusion tractography. From each tract, measures of microscopic damage were assessed, and despite the presence of unilateral lesions, bilateral diffusivity differences in white matter tracts were found comparing patients with normal controls. Consistently, bilateral alterations were also evidenced in specific brain regions linked to the cerebellum and involved in higher-level functions. This could be in line with the evidence that in the presence of unilateral cerebellar lesions, different cognitive functions can be affected and they are not strictly linked to the side of the cerebellar lesion

    Rechargeable-hybrid-seawater fuel cell

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    A novel energy conversion and storage system using seawater as a cathode is proposed herein. This system is an intermediate between a battery and a fuel cell, and is accordingly referred to as a hybrid fuel cell. The circulating seawater in this opencathode system results in a continuous supply of sodium ions, which gives this system superior cycling stability that allows the application of various alternative anodes to sodium metal by compensating for irreversible charge losses. Indeed, hard carbon and Sn-C nanocomposite electrodes were successfully applied as anode materials in this hybrid-seawater fuel cell, yielding highly stable cycling performance and reversible capacities exceeding 110 mAh g-1 and 300 mAh g-1, respectively. © 2014 Nature Publishing Group All rights reservedclose1

    Unlocking the potential of weberite-type metal fluorides in electrochemical energy storage

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    Sodium-ion batteries (NIBs) are a front-runner among the alternative battery technologies suggested for substituting the state-of-the-art lithium-ion batteries (LIBs). The specific energy of Na-ion batteries is significantly lower than that of LIBs, which is mainly due to the lower operating potentials and higher molecular weight of sodium insertion cathode materials. To compete with the high energy density of LIBs, high voltage cathode materials are required for NIBs. Here we report a theoretical investigation on weberite-type sodium metal fluorides (SMFs), a new class of high voltage and high energy density materials which are so far unexplored as cathode materials for NIBs. The weberite structure type is highly favorable for sodium-containing transition metal fluorides, with a large variety of transition metal combinations (M, M’) adopting the corresponding Na2MM’F7 structure. A series of known and hypothetical compounds with weberite-type structure were computationally investigated to evaluate their potential as cathode materials for NIBs. Weberite-type SMFs show two-dimensional pathways for Na+ diffusion with surprisingly low activation barriers. The high energy density combined with low diffusion barriers for Na+ makes this type of compounds promising candidates for cathode materials in NIBs
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