23 research outputs found

    Characterisation of indium phosphide using terahertz radiation

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    Specimens of undoped, n-type and p-type bulk InP have been investigated using THz radiation. Reflection spectroscopy permits the determination of the TO and LO phonon energies as well as the carrier concentration. Absorption spectroscopy reveals transitions between impurity states. We report the first absorption spectrum of an acceptor in InP. The transition energies agree well with electronic Raman scattering and photoluminescence data

    Effects of fluoxetine on functional outcomes after acute stroke (FOCUS): a pragmatic, double-blind, randomised, controlled trial

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    Background Results of small trials indicate that fluoxetine might improve functional outcomes after stroke. The FOCUS trial aimed to provide a precise estimate of these effects. Methods FOCUS was a pragmatic, multicentre, parallel group, double-blind, randomised, placebo-controlled trial done at 103 hospitals in the UK. Patients were eligible if they were aged 18 years or older, had a clinical stroke diagnosis, were enrolled and randomly assigned between 2 days and 15 days after onset, and had focal neurological deficits. Patients were randomly allocated fluoxetine 20 mg or matching placebo orally once daily for 6 months via a web-based system by use of a minimisation algorithm. The primary outcome was functional status, measured with the modified Rankin Scale (mRS), at 6 months. Patients, carers, health-care staff, and the trial team were masked to treatment allocation. Functional status was assessed at 6 months and 12 months after randomisation. Patients were analysed according to their treatment allocation. This trial is registered with the ISRCTN registry, number ISRCTN83290762. Findings Between Sept 10, 2012, and March 31, 2017, 3127 patients were recruited. 1564 patients were allocated fluoxetine and 1563 allocated placebo. mRS data at 6 months were available for 1553 (99·3%) patients in each treatment group. The distribution across mRS categories at 6 months was similar in the fluoxetine and placebo groups (common odds ratio adjusted for minimisation variables 0·951 [95% CI 0·839–1·079]; p=0·439). Patients allocated fluoxetine were less likely than those allocated placebo to develop new depression by 6 months (210 [13·43%] patients vs 269 [17·21%]; difference 3·78% [95% CI 1·26–6·30]; p=0·0033), but they had more bone fractures (45 [2·88%] vs 23 [1·47%]; difference 1·41% [95% CI 0·38–2·43]; p=0·0070). There were no significant differences in any other event at 6 or 12 months. Interpretation Fluoxetine 20 mg given daily for 6 months after acute stroke does not seem to improve functional outcomes. Although the treatment reduced the occurrence of depression, it increased the frequency of bone fractures. These results do not support the routine use of fluoxetine either for the prevention of post-stroke depression or to promote recovery of function. Funding UK Stroke Association and NIHR Health Technology Assessment Programme

    Design of a high temperature superconductor magnetic energy storage systems

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    The University of Wollongong (UoW) has received funding for the research and development of a 20 kJ high temperature superconducting magnetic energy storage device (HTS SMES). This SMES will be operated at 25 K in contrast to most existing HTS designs, which operate at 77K. This paper includes a literature review of the current technology for the configuration of the SMES coil and a summary of the work done at UoW to date. Solenoidal and toroidal coils designs are compared to determine which will provide the required level of energy stored for a minimum superconductor and device volume. The design for the proposed SMES is evaluated with respect to UoW’s requirements

    PRESSURE EFFECTS OF THE ARE SUPPRESSOR GAS, SF6SF_{6}, ON GAS PHASE ELECTROCHROMISM SPECTRA

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    1^{1}M. B. Robin, ``Higher Excited States of Polyatomic Molecules'' (Academic, New York, 1974), Vol. I. This work was supported by the Robert A. Welch Foundation.Author Institution: Department of Chemistry, North Texas State University; Department of Physics, Denison UniversityThe effect of increasing pressure of the are suppressor gas, SF6SF_{6}, on the electrochromism spectra of medium sized polyatomic molecules has been measured. The Rydberg absorptions of molecules have been shown to be particularly sensitive to the pressure of surrounding gases.1gases.^{1} Even for moderate pressures of a few atmospheres, subtle changes in intensity and shape of these bands have been noted. These absorptions of gas phase samples also show a change in total electrochromic effect when subjected to increasing pressures. The net change is, however, greater than was expected and is thought to be the result of variations of the internal electric field as a result of varying pressure. The pressure range of interest is from ca. 1 to 15 atmospheres. The discussion will demonstrate how these effects may be taken into account when calculating excited state properties and how they relate to solvatochromic effects

    Quantifying molecular-level cell adhesion on electroactive conducting polymers using electrochemical-single cell force spectroscopy

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    Single Cell Force Spectroscopy was combined with Electrochemical-AFM to quantify the adhesion between live single cells and conducting polymers whilst simultaneously applying a voltage to electrically switch the polymer from oxidized to reduced states. The cell-conducting polymer adhesion represents the non-specific interaction between cell surface glycocalyx molecules and polymer groups such as sulfonate and dodecylbenzene groups, which rearrange their orientation during electrical switching. Single cell adhesion significantly increases as the polymer is switched from an oxidized to fully reduced state, indicating stronger cell binding to sulfonate groups as opposed to hydrophobic groups. This increase in single cell adhesion is concomitant with an increase in surface hydrophilicity and uptake of cell media, driven by cation movement, into the polymer film during electrochemical reduction. Binding forces between the glycocalyx and polymer surface are indicative of molecular-level interactions and during electrical stimulation there is a decrease in both the binding force and stiffness of the adhesive bonds. The study provides insight into the effects of electrochemical switching on cell adhesion at the cell-conducting polymer interface and is more broadly applicable to elucidating the binding of cell adhesion molecules in the presence of electrical fields and directly at electrode interfaces
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