607 research outputs found
Part IV: Basic Considerations of the Psoralens: Relationship of Molecular Configuration to the Activity of Furocoumarins Which Increase the Cutaneous Responses Following Long Wave Ultraviolet Radiation11From the Division of Dermatology, University of Oregon Medical School, Portland, Oregon.
The Porphyrin Content of Skin**From the Research Laboratories of the Department of Dermatology, Harvard Medical School at the Massachusetts General Hospital, Boston 14, Massachusetts.
Effect of Ultraviolet Irradiation on Biosynthesis of Dna in Guinea-Pig Skin in Vivo
The molecular and metabolic alterations preceding the clinical manifestation of a photobiologic process, the erythematous or sunburn reaction, were investigated in mammalian skin in vivo. The effect of a moderate (2.5–3 times the minimal erythema dose [MED]) and a large (6–8 times MED) dose of ultraviolet radiation (290–320 nm) on the incorporation of [Me-3H]-thymidine into epidermal cell DNA of guinea pigs was studied. The epilated half of the back of each animal was irradiated with various doses of ultraviolet light, and the other half served as the nonirradiated control. The amount of intraperitoneally injected [Me-3H]-thymidine incorporated into the DNA was determined by the isolation of DNA at various time intervals and the measurement of its radioactivity. Significant inhibition of the biosynthesis of DNA (64% of the control) immediately after ultraviolet irradiation was observed. The duration of this inhibition is related to the total dose of ultraviolet light delivered and to the degree of the erythema reaction (i.e., the degree of cellular damage) and can persist from 2.24hr. With a moderate dose, the biosynthesis of new DNA occurs 2hr after irradiation
PP-030 Pattern and frequency of nosocomial infections among Asian Pakistani patients in ICU: an observational study
A Clinical Trial of the Effects of Oral Beta-Carotene on the Responses of Human Skin to Solar Radiation
Beta-carotene (180 mg/day, p. o. ) or a placebo was administered to 30 normal male volunteers for 10 weeks, after which the volunteers were exposed to sunlight in the Arizona desert for up to 2 hours. Beta-carotene had a small but statistically significant effect in increasing the minimal erythema dose of sunburn radiation. The observed effects were too small to recommend the use of beta-carotene as a photoprotective agent for sunburn, but the methods developed provide a workable model for randomized controlled trials for evaluating the efficacy of systemic photoprotective agents
Compton scattering beyond the impulse approximation
We treat the non-relativistic Compton scattering process in which an incoming
photon scatters from an N-electron many-body state to yield an outgoing photon
and a recoil electron, without invoking the commonly used frameworks of either
the impulse approximation (IA) or the independent particle model (IPM). An
expression for the associated triple differential scattering cross section is
obtained in terms of Dyson orbitals, which give the overlap amplitudes between
the N-electron initial state and the (N-1) electron singly ionized quantum
states of the target. We show how in the high energy transfer regime, one can
recover from our general formalism the standard IA based formula for the cross
section which involves the ground state electron momentum density (EMD) of the
initial state. Our formalism will permit the analysis and interpretation of
electronic transitions in correlated electron systems via inelastic x-ray
scattering (IXS) spectroscopy beyond the constraints of the IA and the IPM.Comment: 7 pages, 1 figur
Report on Gun Conditioning Activities at PITZ in 2013
Recently three RF guns were prepared at the Photo Injector Test Facility at DESY, location Zeuthen PITZ for their subsequent operation at FLASH and the European XFEL. The gun 3.1 is a previous cavity design and is currently installed and operated at FLASH, the other two guns 4.3 and 4.4 were of the current cavity design and are dedicated to serve for the start up of the European XFEL photo injector. All three cavities had been dry ice cleaned prior their conditioning and hence showed low dark current levels. The lowest dark current level as low as 60 amp; 956;A at 65MV m field amplitude has been observed for the gun 3.1. This paper reports in details about the conditioning process of the most recent gun 4.4. It informs about experience gained at PITZ during establishing of the RF conditioning procedure and provides a comparison with the other gun cavities in terms of the dark currents. It also summarizes the major setup upgrades, which have affected the conditioning processes of the cavitie
Exoplanets with ELT-METIS I: estimating the direct imaging exoplanet yield around nearby stars within 6.5 parsecs
Stars and planetary system
Improved protocols of secure quantum communication using W states
Recently, Hwang et al. [Eur. Phys. J. D. 61, 785 (2011)] and Yuan et al.
[Int. J. Theo. Phys. 50, 2403 (2011)] have proposed two efficient protocols of
secure quantum communication using 3-qubit and 4-qubit symmetric W state
respectively. These two dense coding based protocols are generalized and their
efficiencies are considerably improved. Simple bounds on the qubit efficiency
of deterministic secure quantum communication (DSQC) and quantum secure direct
communication (QSDC) protocols are obtained and it is shown that dense coding
is not essential for designing of maximally efficient DSQC and QSDC protocols.
This fact is used to design maximally efficient protocols of DSQC and QSDC
using 3-qubit and 4-qubit W states.Comment: 8 page
Quantum walks: a comprehensive review
Quantum walks, the quantum mechanical counterpart of classical random walks,
is an advanced tool for building quantum algorithms that has been recently
shown to constitute a universal model of quantum computation. Quantum walks is
now a solid field of research of quantum computation full of exciting open
problems for physicists, computer scientists, mathematicians and engineers.
In this paper we review theoretical advances on the foundations of both
discrete- and continuous-time quantum walks, together with the role that
randomness plays in quantum walks, the connections between the mathematical
models of coined discrete quantum walks and continuous quantum walks, the
quantumness of quantum walks, a summary of papers published on discrete quantum
walks and entanglement as well as a succinct review of experimental proposals
and realizations of discrete-time quantum walks. Furthermore, we have reviewed
several algorithms based on both discrete- and continuous-time quantum walks as
well as a most important result: the computational universality of both
continuous- and discrete- time quantum walks.Comment: Paper accepted for publication in Quantum Information Processing
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