3,495 research outputs found
Are Asians comfortable with discussing death in health valuation studies? A study in multi-ethnic Singapore
BACKGROUND
To characterize ease in discussing death (EID) and its influence on health valuation in a multi-ethnic Asian population and to determine the acceptability of various descriptors of death and "pits"/"all-worst" in health valuation.
METHODS
In-depth interviews (English or mother-tongue) among adult Chinese, Malay and Indian Singaporeans selected to represent both genders and a wide range of ages/educational levels. Subjects rated using 0–10 visual analogue scales (VAS): (1) EID, (2) acceptability of 8 descriptors for death, and (3) appropriateness of "pits" and "all-worst" as descriptors for the worst possible health state. Subjects also valued 3 health states using VAS followed by time trade-off (TTO). The influence of sociocultural variables on EID and these descriptors was studied using univariable analyses and multiple linear regression (MLR). The influence of EID on VAS/TTO utilities with adjustment for sociocultural variables was assessed using MLR.
RESULTS
Subjects (n = 63, 35% Chinese, 32% Malay, median age 44 years) were generally comfortable with discussing death (median EID: 8.0). Only education significantly influenced EID (p = 0.045). EID correlated weakly with VAS/TTO scores (range: VAS: -0.23 to 0.07; TTO: -0.14 to 0.11). All subjects felt "passed away", "departed" and "deceased" were most acceptable (median acceptability: 8.0) while "sudden death" and "immediate death" were least acceptable (median acceptability: 5.0). Subjects clearly preferred "all-worst" to "pits" (63% vs. 19%, p < 0.001).
CONCLUSION
Singaporeans were generally comfortable with discussing death and had clear preferences for several descriptors of death and for "all-worst". EID is unlikely to influence health preference measurement in health valuation studies
An easy-to-use diagnostic system development shell
The Diagnostic System Development Shell (DSDS), an expert system development shell for diagnostic systems, is described. The major objective of building the DSDS is to create a very easy to use and friendly environment for knowledge engineers and end-users. The DSDS is written in OPS5 and CommonLisp. It runs on a VAX/VMS system. A set of domain independent, generalized rules is built in the DSDS, so the users need not be concerned about building the rules. The facts are explicitly represented in a unified format. A powerful check facility which helps the user to check the errors in the created knowledge bases is provided. A judgement facility and other useful facilities are also available. A diagnostic system based on the DSDS system is question driven and can call or be called by other knowledge based systems written in OPS5 and CommonLisp. A prototype diagnostic system for diagnosing a Philips constant potential X-ray system has been built using the DSDS
The activation energy for GaAs/AlGaAs interdiffusion
Copyright 1997 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. This article appeared in Journal of Applied Physics 82, 4842 (1997) and may be found at
Magnetic properties of exchange biased and of unbiased oxide/permalloy thin layers: a ferromagnetic resonance and Brillouin scattering study
Microstrip ferromagnetic resonance and Brillouin scattering are used to
provide a comparative determination of the magnetic parameters of thin
permalloy layers interfaced with a non-magnetic (Al2O3) or with an
antiferromagnetic oxide (NiO). It is shown that the perpendicular anisotropy is
monitored by an interfacial surface energy term which is practically
independent of the nature of the interface. In the investigated interval of
thicknesses (5-25 nm) the saturation magnetisation does not significantly
differ from the reported one in bulk permalloy. In-plane uniaxial anisotropy
and exchange-bias anisotropy are also derived from this study of the dynamic
magnetic excitations and compared to our independent evaluations using
conventional magnetometryComment: 7 pages, 6 figures, submited to Journal of Physics: Condensed Matte
Structural Characterization of Rapid Thermal Oxidized Si\u3csub\u3e1−x−y\u3c/sub\u3eGe\u3csub\u3ex\u3c/sub\u3eC\u3csub\u3ey\u3c/sub\u3e Alloy Films Grown by Rapid Thermal Chemical Vapor Deposition
The structural properties of as-grown and rapid thermal oxidized Si1−x−yGexCy epitaxial layers have been examined using a combination of infrared, x-ray photoelectron, x-ray diffraction, secondary ion mass spectroscopy, and Raman spectroscopy techniques. Carbon incorporation into the Si1−x−yGexCy system can lead to compressive or tensile strain in the film. The structural properties of the oxidized Si1−x−yGexCy film depend on the type of strain (i.e., carbon concentration) of the as-prepared film. For compressive or fully compensated films, the oxidation process drastically reduces the carbon content so that the oxidized films closely resemble to Si1−xGex films. For tensile films, two broad regions, one with carbon content higher and the other lower than that required for full strain compensation, coexist in the oxidized films
Raman spectroscopy of epitaxial graphene on a SiC substrate
The fabrication of epitaxial graphene (EG) on SiC substrate by annealing has
attracted a lot of interest as it may speed up the application of graphene for
future electronic devices. The interaction of EG and the SiC substrate is
critical to its electronic and physical properties. In this work, Raman
spectroscopy was used to study the structure of EG and its interaction with SiC
substrate. All the Raman bands of EG blue shift from that of bulk graphite and
graphene made by micromechanical cleavage, which was attributed to the
compressive strain induced by the substrate. A model containing 13 x 13
honeycomb lattice cells of graphene on carbon nanomesh was constructed to
explain the origin of strain. The lattice mismatch between graphene layer and
substrate causes the compressive stress of 2.27 GPa on graphene. We also
demonstrate that the electronic structures of EG grown on Si and C terminated
SiC substrates are quite different. Our experimental results shed light on the
interaction between graphene and SiC substrate that are critical to the future
applications of EG.Comment: 20 pages, 5 figure
Poly-(γ-glutamic acid) Production and Optimization from Agro-Industrial Bioresources as Renewable Substrates by Bacillus sp. FBL-2 through Response Surface Methodology
We optimized culture conditions using Bacillus sp. FBL-2 as a poly-(γ-glutamic acid) (PGA)
producing strain isolated from cheonggukjang. All experiments were performed under aerobic conditions
using a laboratory scale 2.5 L fermentor. We investigated the effects of fermentation parameters
(temperature, pH, agitation, and aeration) and medium components (glutamic acid, citric acid, and yeast
extract) on poly-(γ-glutamic acid) production, viscosity, and dry cell mass. A non-optimized fermentation
method (1.5 vvm, 350 rpm, and 37 °C) yielded PGA, viscosity, and dry cell mass at levels of 100.7 g/L,
483.2 cP, and 3.4 g/L, respectively. L-glutamic acid, citric acid, and yeast extract supplementation enhanced
poly-(γ-glutamic acid) production to 175.9 g/L. Additionally, the production of poly-(γ-glutamic acid) from
rice bran and wheat bran was assessed using response surface methodology (central composite rotatable
design). Agricultural by-products (rice bran and wheat bran) and H2SO4 were selected as factors,
and experiments were performed by combining various component concentrations to determine optimal
component concentrations. Our experimentally-derived optimal parameters included 38.6 g/L of rice bran,
0.42% of H2SO4, 28.0 g/L of wheat bran, and 0.32% of H2SO4. Under optimum conditions, rice bran
medium facilitated poly-(γ-glutamic acid) production of up to 22.64 g/L, and the use of wheat bran medium
yielded up to 14.6 g/L. Based on a validity test using the optimized culture conditions, poly-(γ-glutamic
acid) was produced at 47.6 g/L and 36.4 g/L from these respective mediums, and both results were higher
than statistically predicted. This study suggests that rice bran can be used as a potential alternative substrate
for poly-(γ-glutamic acid) production
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