71 research outputs found
Near-forward Raman scattering by bulk and surface phonon-polaritons in the model percolation-type ZnBeSe alloy
We study the bulk and surface phonon-polaritons of the Zn0.67Be0.33Se
zincblende alloy by near-forward Raman scattering. The short (Be-Se) bond
exhibits a distinct percolation doublet in the conventional backscattering
Raman spectra, corresponding to a three-mode behavior in total
[1(Zn-Se),2(Be-Se)] for Zn0.67Be0.33Se. This offers an opportunity to achieve a
refined understanding of the phonon-polariton modes of a zincblende alloy
beyond the current two-mode approximation, corresponding to a
[1(Zn-Se),1(Be-Se)] description in the present case. The discussion is
supported by contour modeling of the Raman signals of the multi-mode bulk and
surface phonon-polaritons within the formalism of the linear dielectric
response
Thermal diffusivity, effusivity and conductivity of CdMnTe mixed crystals
Cd1-xMnxTe mixed crystals belong to a class of materials called ‘‘semimagnetic semiconductor’’ or diluted magnetic semiconductor (DMS) with addition of magnetic ions like Mn2+ implemented into crystal structure. The crystals under investigation were grown from the melt by the high pressure high temperature modified Bridgman method in the range of composition 0 < x < 0.7. Thermal properties of these compounds have been investigated by means of photopyroelectric (PPE) calorimetry in both, back and front detection configuration. The values of the thermal diffusivity and effusivity were derived from experimental data. Thermal conductivity of the specimens was calculated from the simple theoretical dependencies between thermal parameters. The influence of Mn concentration on thermal properties of Cd1-xMnxTe crystals have been presented and discussed
A Soluble Form of the High Affinity IgE Receptor, Fc-Epsilon-RI, Circulates in Human Serum
Soluble IgE receptors are potential in vivo modulators of
IgE-mediated immune responses and are thus important for our basic understanding
of allergic responses. We here characterize a novel soluble version of the
IgE-binding alpha-chain of Fc-epsilon-RI (sFcεRI), the high affinity
receptor for IgE. sFcεRI immunoprecipitates as a protein of ∼40 kDa and
contains an intact IgE-binding site. In human serum, sFcεRI is found as a
soluble free IgE receptor as well as a complex with IgE. Using a newly
established ELISA, we show that serum sFcεRI levels correlate with serum IgE
in patients with elevated IgE. We also show that serum of individuals with
normal IgE levels can be found to contain high levels of sFcεRI. After
IgE-antigen-mediated crosslinking of surface FcεRI, we detect sFcεRI in
the exosome-depleted, soluble fraction of cell culture supernatants. We further
show that sFcεRI can block binding of IgE to FcεRI expressed at the cell
surface. In summary, we here describe the alpha-chain of FcεRI as a
circulating soluble IgE receptor isoform in human serum
Comparison of the benefits of cochlear implantation versus contra-lateral routing of signal hearing aids in adult patients with single-sided deafness: study protocol for a prospective within-subject longitudinal trial
Background
Individuals with a unilateral severe-to-profound hearing loss, or single-sided deafness, report difficulty with listening in many everyday situations despite having access to well-preserved acoustic hearing in one ear. The standard of care for single-sided deafness available on the UK National Health Service is a contra-lateral routing of signals hearing aid which transfers sounds from the impaired ear to the non-impaired ear. This hearing aid has been found to improve speech understanding in noise when the signal-to-noise ratio is more favourable at the impaired ear than the non-impaired ear. However, the indiscriminate routing of signals to a single ear can have detrimental effects when interfering sounds are located on the side of the impaired ear. Recent published evidence has suggested that cochlear implantation in individuals with a single-sided deafness can restore access to the binaural cues which underpin the ability to localise sounds and segregate speech from other interfering sounds.
Methods/Design
The current trial was designed to assess the efficacy of cochlear implantation compared to a contra-lateral routing of signals hearing aid in restoring binaural hearing in adults with acquired single-sided deafness. Patients are assessed at baseline and after receiving a contra-lateral routing of signals hearing aid. A cochlear implant is then provided to those patients who do not receive sufficient benefit from the hearing aid. This within-subject longitudinal design reflects the expected care pathway should cochlear implantation be provided for single-sided deafness on the UK National Health Service. The primary endpoints are measures of binaural hearing at baseline, after provision of a contra-lateral routing of signals hearing aid, and after cochlear implantation. Binaural hearing is assessed in terms of the accuracy with which sounds are localised and speech is perceived in background noise. The trial is also designed to measure the impact of the interventions on hearing- and health-related quality of life.
Discussion
This multi-centre trial was designed to provide evidence for the efficacy of cochlear implantation compared to the contra-lateral routing of signals. A purpose-built sound presentation system and established measurement techniques will provide reliable and precise measures of binaural hearing.
Trial registration
Current Controlled Trials http://www.controlled-trials.com/ISRCTN33301739 (05/JUL/2013
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