53 research outputs found
Autofluorescence Lifetimes in Patients With Choroideremia Identify Photoreceptors in Areas With Retinal Pigment Epithelium Atrophy.
The purpose of this study was to investigate fundus autofluorescence lifetimes in patients with choroideremia and to identify tissue-specific lifetime characteristics and potential prognostic markers.
Autofluorescence lifetimes of the retina were measured in two spectral channels (498-560 nm and 560-720 nm) in patients with choroideremia and age-matched healthy controls. Furthermore, autofluorescence intensities and spectral-domain optical coherence tomography (OCT) data were acquired and compared to fundus autofluorescence lifetime data.
Sixteen eyes from 8 patients with advanced choroideremia (mean ± SD age, 55 ± 13 years) were included in this study and compared with 10 age-matched healthy participants. Whereas fundus autofluorescence intensity measurement identified areas of remaining retinal pigment epithelium (RPE), autofluorescence lifetime maps identified areas with remaining photoreceptor layers in OCT but RPE atrophy. In these areas, mean (±SEM) lifetimes were 567 ± 59 ps in the short and 603 ± 49 ps in the long spectral channels (+98% and +88% compared to controls). In areas of combined RPE atrophy and loss of photoreceptors, autofluorescence lifetimes were significantly prolonged by 1116 ± 63 ps (+364%) in the short and by 915 ± 52 ps (+270%) in the long spectral channels compared with controls.
Because autofluorescence lifetimes identify areas of remaining photoreceptors in the absence of RPE, this imaging modality may be useful to monitor disease progression in the natural course of disease and in context of potential future therapeutic interventions
Gravitational excitons from extra dimensions
Inhomogeneous multidimensional cosmological models with a higher dimensional
space-time manifold are investigated under dimensional reduction. In the
Einstein conformal frame, small excitations of the scale factors of the
internal spaces near minima of an effective potential have a form of massive
scalar fields in the external space-time. Parameters of models which ensure
minima of the effective potentials are obtained for particular cases and masses
of gravitational excitons are estimated.Comment: Revised version --- 12 references added, Introduction enlarged, 20
pages, LaTeX, to appear in Phys.Rev.D56 (15.11.97
Tunneling spectroscopy in the magnetic superconductor TmNi2B2C
We present new measurements about the tunneling conductance in the
borocarbide superconductor TmNiBC. The results show a very good
agreement with weak coupling BCS theory, without any lifetime broadening
parameter, over the whole sample surface. We detect no particular change of the
tunneling spectroscopy below 1.5K, when both the antiferromagnetic (AF) phase
and the superconducting order coexist.Comment: Submitted to Phys. Rev. B, Rapid Communication
Physical Parameters of Some Close Binaries: ET Boo, V1123 Tau, V1191 Cyg, V1073 Cyg and V357 Peg
With the aim of providing new and up-to-date absolute parameters of some
close binary systems, new BVR CCD photometry was carried out at the Ankara
University Observatory (AUG) for five eclipsing binaries, ET Boo, V1123 Tau,
V1191 Cyg, V1073 Cyg and V357 Peg between April, 2007 and October, 2008. In
this paper, we present the orbital solutions for these systems obtained by
simultaneous light and radial velocity curve analyses. Extensive orbital
solution and absolute parameters for ET Boo system were given for the first
time through this study. According to the analyses, ET Boo is a detached binary
while the parameters of four remaining systems are consistent with the nature
of contact binaries. The evolutionary status of the components of these systems
are also discussed by referring to their absolute parameters found in this
study.Comment: this accepted paper will be published in New Astronom
Brane Inflation, Solitons and Cosmological Solutions: I
In this paper we study various cosmological solutions for a D3/D7 system
directly from M-theory with fluxes and M2-branes. In M-theory, these solutions
exist only if we incorporate higher derivative corrections from the curvatures
as well as G-fluxes. We take these corrections into account and study a number
of toy cosmologies, including one with a novel background for the D3/D7 system
whose supergravity solution can be completely determined. This new background
preserves all the good properties of the original model and opens up avenues to
investigate cosmological effects from wrapped branes and brane-antibrane
annihilation, to name a few. We also discuss in some detail semilocal defects
with higher global symmetries, for example exceptional ones, that could occur
in a slightly different regime of our D3/D7 model. We show that the D3/D7
system does have the required ingredients to realise these configurations as
non-topological solitons of the theory. These constructions also allow us to
give a physical meaning to the existence of certain underlying homogeneous
quaternionic Kahler manifolds.Comment: Harvmac, 115 pages, 9 .eps figures; v2: typos corrected, references
added and the last section expanded; v3: Few minor typos corrected and
references added. Final version to appear in JHE
Sidegating characteristics as a function of distance and dose for implanted and metallic sidegates on proton-isolated GaAs
Guidance on communicating about uncertainties in nuclear emergency management
Within the European project CONFIDENCE, an extensive research programme has been conducted on a range of different tools, including Apps, SMS, numerical, narrative or mixed news messages and videos linked to uncertainty communication following potential nuclear or radiological emergencies. For this purpose, qualitative and quantitative research methods were applied in different European countries. Based on the results of these studies, we have formulated guidelines for efficient and effective communication about uncertainties that can be used in nuclear or radiological emergencies
Social uncertainties related to stable iodine intake in a nuclear emergency
Intake of stable iodine intake is considered as an effective countermeasure for reducing the risk of thyroid cancer in an eventual release of radioactive iodine following nuclear accident. However, there are a number of value and social uncertainties that are likely to impact on accident management. These include differences in public response as well as decisions made by emergency management actors during an actual incident. In order to explore these sources of uncertainty, this paper explored social uncertainties related to the potential administration of stable iodine. First, public understanding and compliance with the advice of authorities was studied by surveys, showing that less than half of the public knew when iodine tablets should be taken, or understood their protective role. There were also country specific differences in the level of expected compliance with authorities’ advice. Second, social uncertainties were identified through observations of emergency exercises; these were revealed to be mainly related to timing, public response, communication, effectiveness, cross-border issues and first responders. Third, studies on factors influencing communication about stable iodine were carried out and showed that public understanding and compliance with advice could be improved by communicating numerical and narrative information. Overall, the results indicate that enhanced focus on social uncertainties during the preparedness phase may improve the effectiveness of stable iodine administration in case of an emergency
Transduction of intracellular and intercellular dynamics in yeast glycolytic oscillations.
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