Arsenaultmathiesen3543

Main results.We evaluated the performance of the imager in both simulated and prototype form with radionuclide177Lu (cascade photon emitter). On the simulated imager, the coincidence detection efficiency at the center of FOV was 3.85 × 10-6, the spatial resolution was 7.0 mm. On the prototype imager, the corresponding values were 3.20 × 10-6and 6.7 mm, respectively. Simulated hot-rod and experimental cardiac phantom studies demonstrate the first three-dimensional cascade gamma coincidence imager is fully functional.First-principles calculations and particle swarm optimization algorithm are combined to predict the crystal structures in the pressure range from 0 to 100 GPa. Four phases of ThBC are determined, including theP4122,Cmcm,CmceandImmmphases, in which theCmcm,CmceandImmmphases are newly predicted structures. The mechanical, electronic and thermodynamic properties of the four phases are investigated. Eganelisib in vitro According to the enthalpy-pressure and volume-pressure curves, the phase transition pressure from theP4122 phase to theCmcmphase is 15 GPa, theCmcmto theCmceis 36 GPa and theCmceto theImmmis 69 GPa. All the transitions belong to the first-order phase transition. Based on the calculated elastic constants, theP4122,Cmcm,CmceandImmmphases exhibit brittle nature. The Young's moduli show that theP4122 phase has the largest degree of anisotropy, and theImmmphase has the smallest. The calculated density of states reveal that theP4122,Cmcm,CmceandImmmphases are all metallic.Polyaniline, as a kind of conductive polymer with commercial application prospects, is still under researches in its synthesis and applications. In this work, polyaniline was fabricated on flexible substrates including carbon cloths and polyethylene naphthalate byin-situelectropolymerization method. The synthesized flexible electrodes were characterized by scanning electron microscopy, High resolution transmission electron microscope, atomic force microscope, Fourier transform infrared, X-ray diffraction, and X-ray photoelectron spectroscopy. Owing to the conductivity and the reversible redox property, the polyaniline/carbon cloth electrodes show excellent properties such as decent supercapacitor performance and good detection capability toward ascorbic acid. As supercapacitors, the electrodes exhibit a specific capacitance as high as 776 F g-1at a current density of 1 A g-1and a long cycle life of 20,000 times in the three-electrode system. As ascorbic acid sensors, the flexible electrodes demonstrate stable response to ascorbic acid in the range of 1-3,000 μM with an outstanding sensitivity (4,228 μA mM-1cm-2), low detection limit (1 μM), and a fast response time. This work holds promise for high-performance and low-cost flexible electrodes for both supercapacitors and non-enzymatic ascorbic acid sensors, and may inspire inventions of self-powered electrochemical sensor.Many technological applications demand large amount of nanoparticles with well-defined properties, which is feasible only by using large-scale production methods. In this framework, we have performed structural and local geometric investigations of cobalt oxide nanoparticles synthesized by high temperature arc plasma route in helium and in air atmosphere with different arc currents, a competitive and low cost technological approach to synthesize large quantity of different types of nanoparticles. The complex scenario of phase fraction, shape, size distribution and hysteresis loop features of high temperature arc plasma synthesis of nanoparticles can be determined by the arc current and the selected gas. X-ray diffraction (XRD) patterns reveal a multicomponent phase formation containing cubic cobaltous oxide (CoO), cobaltic oxide (Co3O4) and metallic cobalt phases. The synthesis of different phases is confirmed by X-ray absorption spectroscopy (XAS) measurements at the Co K-edge. Both Extended X-ray absorption fine structure (EXAFS) and X-ray absorption near edge structure (XANES) analyses show the presence of metallic nanoparticles in He ambient at high arc current. Moreover, high-resolution transmission electron microscopy (HRTEM) images and magnetic hysteresis loop measurements show that the mean particle size increases and the coercivity decreases with increasing arc current in air ambient due to the intense particle-particle interaction. At variance, in He ambient synthesized samples due to the high quenching rate and the high thermal conductivity, a multi-domain formation in which the nanoparticles' crystalline fraction decreases and a fluctuating coercivity due to core-shell structure is observed.Although supercapacitors have attracted more and more attention owing to their fast charging speed and high power density, their wide applications have still been limited by their low energy density. In this study, a new CuS-nanoparticle-decorated Ti3C2Txelectrode material is fabricated via a facilein situsynthesis strategy at room temperature. CuS nanoparticles, generated from thein situreaction of Cu (NO3)2·3H2O with Na2S·9H2O, are anchored between the Ti3C2Txinterlayers through electrostatic interaction. This type of structural construction is found capable of not only reducing the surface oxidation of Ti3C2Tx, but also preventing the accumulation of CuS nanoparticles by the template effect of Ti3C2Txnanoplates. As a result, the CuS/Ti3C2Txnanohybrid delivers a maximum specific capacitance of 911 F g-1at 1 A g-1and a good cycling stability. A symmetric supercapacitor fabricated using the CuS/Ti3C2Txnanohybrid as the electrode material exhibits an energy density of 43.56 W h kg-1with a power density of 475 W kg-1. Consequently, this work provides a new perspective of microstructural design for the preparation of electrode materials with superhigh specific capacitance through an easy and low-costin situ-reaction method at room temperature.Molybdenum disulfide (MoS2) mono/bilayer have been systematically investigated using atmospheric-pressure mist chemical vapor deposition (mist CVD) from (NH4)2MoS4dissolved in N-methyl-2-pyrrolidone as a precursor. Film deposition was performed by alternating MoS2mist storage within a closed chamber and mist exhaust, i.e. sequential mist supply mode at different furnace temperatures, storage times of precursor, and repetition cycles of mist supply on thermally grown SiO2(th-SiO2) and mist-CVD grown Al1-xTixOy(ATO) layers coated on p+-Si substrates. The average size of the MoS2flake and their number of stack layers could be controlled by tuning the deposition parameters combined with substrate pretreatment. Field-effect transistors with MoS2atomic mono/bilayer as a channel layer exhibited mobility up to 31-40 (43-55) cm2V-1s-1with a threshold voltage of -1.6 (-0.5) V, subthreshold slope of 0.8 (0.11) V dec.-1, and on/off ratio of 3.2 × 104(3.6 × 105) onth-SiO2(ATO) layers as gate dielectric layers without mechanical exfoliation. These findings imply that mist CVD is available for the synthesis of metal transition metal dichalcogenide and metal oxide layers as channel and gate dielectric layers, respectively.Numerous commercial technologies for online treatment monitoring (OTM) in radiotherapy (RT) are currently available including electronic portal imaging device (EPID) in vivo dosimetry (IVD), transmission detectors and log files analysis. Despite this, in the UK there exists limited guidance on how to implement and commission a system for clinical use or information about the resources required to set up and maintain a service. A Radiotherapy Special Interest Group (RTSIG) working party, established by Institute of Physics and Engineering in Medicine (IPEM) was formed with a view to reassess the current practice for OTM in the UK and an aim to develop consensus guidelines for the implementation of a system. A survey distributed to Heads of Medical Physics at 71 UK RT departments investigated availability of OTM in the UK; estimates of workload; clinical implementation; methods of analysis; quality assurance; and opinions on future directions. The survey achieved a 76% response rate and demonstrated that OTM is widely supported in the UK, with 87% of respondents indicating all patients should undergo OTM. EPID IVD (EIVD) was the most popular form of OTM. An active EIVD service was reported by 37% of respondents, with 84% believing it was the optimal solution. This demonstrates a steady increase in adoption since 2012. Other forms of OTM were in use but they had only been adopted by a minority of centres. Financial barriers and the increase of staff workload continue to hinder wider implementation in other centres. Device automation and integration is a key factor for successful future adoption and requires support between treatment machine and OTM manufacturers. The survey has provided an updated analysis on the use of OTM methods across the UK. Future guidance is recommended on commissioning, adoption of local tolerances and root-cause analysis strategies to assist departments intending to implement OTM.Carbon dots (CDs) endowed with outstanding physico-chemical characteristics expeditiously garnered tremendous popularity in the scientific community. CDs can be synthesized from a variety of natural resources and can replace metal semiconductor quantum dots in the range of applications such as bio-imaging, sensing and catalysis. Herein, CDs are green synthesized fromBeta vulgarisvia a single step hydrothermal approach (b-CDs). The synthesized carbon dots are characterized using UV-visible spectrophotometry, Fluorescence spectroscopy, High resolution transmission electron microscopy (HR-TEM), Fourier transform infrared spectroscopy (FT-IR), x-ray diffraction technique (XRD) and Raman spectroscopy. The b-CDs hence developed exhibited the signature 'excitation-dependent fluorescence emission' with its most intense emission in the green region. The quantum yield for the b-CDs obtained by this synthetic approach evinced an appreciable value of 11.6%. The antioxidant property of b-CDs are evaluated using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) assay to obtain a maximum scavenging activity of 94.5% at a concentration of 1000μg ml-1and its underlying mechanisms are illustrated. The blood compatibility of b-CDs are assessed using haemolysis assay and the cytotoxicity evaluated using MTT assay shows significant cell growth-inhibition against the human breast cancer (MCF-7) and hepatocellular carcinoma (HepG2) cell lines. This succinct study demonstrates the inherent therapeutic potential of biocompatible carbon dots.Altering physicochemical properties of TiO2 based on modifying the cation and anion structure of ionic liquids (ILs) is of great interests for environment. Up to date, the research involving IL-assisted synthesis of TiO2 was focused on imidazolium IL, and much less attention was devoted to IL with other structures. Hence, strategy for preparation of TiO2 in phosphonium IL is presented to control the growth of TiO2 nanocrystals. The as-prepared noble cerium-doped nitrogen-rich phosphonium IL-TiO2 photocatalyst with assisted by tributyl(propyl)phosphonium tetrafluoroborate exhibits a higher specific surface area and smaller crystallite size, which is conducive to the production of more and faster active substance, such as hydroxyl oxygen. When evaluated for photocatalysis of gaseous toluene under visible light irradiation, the sample manifests high degradation rate and efficiency, as well as excellent recycling performance due to the existence of superoxide radical produced by the Ce 3+/Ce 4+ redox reaction. The introduction of phosphonium IL and Ce greatly enhanced charge separation efficiency and promoted production of active substances.