19 research outputs found
Late growth stages and post-growth diffusion in organic epitaxy: PTCDA on Ag(111)
The late growth stages and the post-growth diffusion of crystalline organic
thin films have been investigated for 3,4,9,10-perylenetetracarboxylic
dianhydride (PTCDA) on Ag(111), a model system in organic epitaxy. In situ
x-ray measurements at the anti-Bragg point during the growth show intensity
oscillations followed by a time-independent intensity which is independent of
the growth temperature. At T > 350 K, the intensity increases after growth up
to a temperature-dependent saturation value due to a post-growth diffusion
process. The time-independent intensity and the subsequent intensity recovery
have been reproduced by models based on the morphology change as a function of
the growth temperature. The morphology found after the post-growth diffusion
processes has been studied by specular rod measurements.Comment: 9 pages, 8 figures, accepted for publication in Surface Scienc
Quantitative conditional quantum erasure in two-atom resonance fluorescence
We present a conditional quantum eraser which erases the a priori knowledge
or the predictability of the path a photon takes in a Young-type double-slit
experiment with two fluorescent four-level atoms. This erasure violates a
recently derived erasure relation which must be satisfied for a conventional,
unconditional quantum eraser that aims to find an optimal sorting of the system
into subensembles with particularly large fringe visibilities. The conditional
quantum eraser employs an interaction-free, partial which-way measurement which
not only sorts the system into optimal subsystems with large visibility but
also selects the appropriate subsystem with the maximum possible visibility. We
explain how the erasure relation can be violated under these circumstances.Comment: Revtex4, 12pages, 4 eps figures, replaced with published version,
changes in Sec. 3, to appear in Physical Review
A randomized, double-blind, placebo-controlled trial evaluating cysteamine in Huntington's disease
BACKGROUND: Cysteamine has been demonstrated as potentially effective in numerous animal models of Huntington\u27s disease.
METHODS: Ninety-six patients with early-stage Huntington\u27s disease were randomized to 1200 mg delayed-release cysteamine bitartrate or placebo daily for 18 months. The primary end point was the change from baseline in the UHDRS Total Motor Score. A linear mixed-effects model for repeated measures was used to assess treatment effect, expressed as the least-squares mean difference of cysteamine minus placebo, with negative values indicating less deterioration relative to placebo.
RESULTS: At 18 months, the treatment effect was not statistically significant - least-squares mean difference, -1.5 ± 1.71 (P = 0.385) - although this did represent less mean deterioration from baseline for the treated group relative to placebo. Treatment with cysteamine was safe and well tolerated.
CONCLUSIONS: Efficacy of cysteamine was not demonstrated in this study population of patients with Huntington\u27s disease. Post hoc analyses indicate the need for definitive future studies. © 2017 International Parkinson and Movement Disorder Society