8,506 research outputs found
Consumer Awareness of the Avian Influenza Threat in Taiwan
Replaced with revised version of paper 06/19/07.consumer awareness, risk perceptions, avian influenza, Taiwan, Consumer/Household Economics, Livestock Production/Industries, M30,
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Hospitality Financial Accounting by Jerry J. Weygandt, Donald E. Kieso, Paul D. Kimmel, and Agnes L. DeFranco
Effect of austempering time on the microstructure and carbon partitioning of ultrahigh strength steel 56NiCrMoV7
Ultrahigh strength steel 56NiCrMoV7 was austempered at 270 °C for different durations in order to investigate the microstructure evolution, carbon partitioning behaviour and hardness property. Detailed microstructure has been characterised using optical microscopy and field emission gun scanning electron microscopy. A newly developed X-ray diffraction method has been employed to dissolve the bainitic/martensitic ferrite phase as two sub-phases of different tetragonal ratios, which provides quantitative analyses of the carbon partitioning between the resultant ferrites and the retained austenite. The results show that, a short-term austempering treatment was in the incubation period of the bainite transformation, which resulted in maximum hardness being equivalent to the oil-quenching treatment. The associated microstructure comprises fine carbide-free martensitic and bainitic ferrites of supersaturated carbon contents as well as carbon-rich retained austenite. In particular, the short-term austempering treatment helped prevent the formation of lengthy martensitic laths as those being found in the microstructure of oil-quenched sample. When the austempering time was increased from 20 to 80 min, progressive decrease of the hardness was associated with the evolution of the microstructure, including progressive coarsening of bainitic ferrite, carbide precipitating inside high-carbon bainitic ferrite and its subsequent decarbonisation
Avian Influenza Threat and its Potential Impact on Demand for Chicken and Eggs
A highly pathogenic H5N1 strain of avian influenza (AI) has been confirmed in 420 human cases and has caused 257 deaths in the world starting from 2003. Using face-to-face interviews, our data were collected by utilizing a stratified sampling scheme following the distribution of gender and age in three major metropolitan areas in Taiwan, including Taipei, Taichung, and Kaohsiung. The questionnaire was designed to retrieve information including AI knowledge, risk perceptions, and behavioral changes of two types of consumers, primary shoppers and general consumers. In total, 501 primary shoppers and 505 general consumers completed the survey in June 2007 and were recorded for analysis. The empirical results show several interesting findings, especially, that risk perception and some socioeconomic characteristics such as age are the key factor which determines changes in purchasing behavior.avian influenza, knowledge, risk perception, Tobit model, Taiwan, Consumer/Household Economics, Livestock Production/Industries, M30,
Ultrastructural and Functional Effects of Lipopolysaccharide and Interleukin-2 on Human NK Cells
Bacterial endotoxin (lipopolysaccharide, LPS) and interleukin-2 (IL-2) are known to stimulate NK cell mediated cytotoxicity against tumor cells. In the present report we sought to correlate the stimulatory effect of LPS and IL-2 on NK cell activity with ultrastructural changes which occurred as a result of such stimulation. Peripheral blood mononuclear cells (PBMC) were purified from healthy donors by a Ficoll-Hypaque density gradient technique. Leu-11a+ NK cells were isolated by flow microfluorometry using a monoclonal FITC conjugated anti-Leu-11a antibody and a FACS II cell sorter. The PBMC were incubated, respectively, with E. coli LPS or recombinant IL-2 (IL-2) for various- time periods. Sorted Leu-11a+ NK cells were incubated with LPS for 24 hours. The NK cytotoxicity in the PBMC and sorted Leu-11a+ cells was assessed by a 51Cr release technique using K562 tumor cells as targets. Leu-11a+ NK cells were identified by immunoelectron microscopy using anti-Leu-11a antibody and labeling with horseradish peroxidase or colloidal gold. Results showed that both LPS and IL-2 significantly enhanced the cytotoxic activity of PBMC. The cytotoxicity of sorted Leu-11a+ cells was augmented by LPS. Recombinant IL-2 induced a significant increase in the number of dense granules, hypertrophy of Golgi apparatus and rough endoplasmic reticulum, and mitosis of Leu-7+ cells and Leu-11a+ cells 4 or 7 days after stimulation. These data indicate that: (1) the effect of LPS on the enhancement of NK cytotoxicity in PBMC may be a direct and/or indirect process involving production of lymphokines; (2) LPS has a direct effect on sorted Leu-11a+ cells; (3) IL-2 stimulates mitosis of Leu-7+ cells and Leu-11a+ cells; and (4) the LPS or IL-2 induced ultrastructural changes in Leu-11a+ cells are consistent with the enhanced NK cytotoxicity
Fabrication of Microneedles
[[abstract]]This research paper was performed to study and utilizes two kinds of materials which match with two different fabrications in order to design an ideal shape of microneedles. The technology employs the polymer microneedles and the silicon microneedles with the height of 236 mum and 350 mum respectively. Moreover, the transdermal drug delivery investigation was conducted by using the fabricated samples to estimate the feasibility of the microneedles. Polymer microneedles were formed by molding the V-grooves structure on silicon wafer. The SU-8 negative photoresist was introduced for the subject structural material of the microneedles. Silicon microneedles were formed by KOH etching solution, solely depending on controlling etching time and the principle of fast-etching planes.[[conferencetype]]國際[[conferencedate]]20070116~20070119[[booktype]]紙本[[iscallforpapers]]Y[[conferencelocation]]Bangkok, Thailan
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Vertex Functions in K-Meson-Nucleon Scattering
The purpose of this study was to investigate some theoretical approaches to the scattering of positive k-mesons by nucleons in an attempt to explain the experimental data. In this work the problem has been investigated by the technique of the weak coupling approximation
Dynamic Analysis of a Rotating Shaft Subject to the Double Cutting Force and Time-varying Mass Effects of the Rod
AbstractThis paper investigates the dynamic behaviors of a rotating shaft subjected to the double cutting force and time-varying mass effects. The Timoshenko beam theory is used to model the rotating shaft, and the general boundary condition is assumed as the clamped-hinged supports. This system is used to simulate the manufacture process of the double turret CNC lathes, and the mass of the rod which is reduced gradually in cutting process. The system equations of motion are derived based on the global assumed mode method, and the dynamic responses of the system are obtained by Runge-Kutta numerical method. The transformation matrix is derived to make the equation of motion completing the boundary geometric constraints. The numerical results compare the dynamic response in different moving speeds and skew angles of the cutting forces with/without the time-varying mass effects. Additionally, this paper compares the response with single cutting force and double force. The results show that the double moving force system can reduce not only the machining time but also the amplitude of shaft vibration
Tailoring excitonic states of van der Waals bilayers through stacking configuration, band alignment and valley-spin
Excitons in monolayer semiconductors have large optical transition dipole for
strong coupling with light field. Interlayer excitons in heterobilayers, with
layer separation of electron and hole components, feature large electric dipole
that enables strong coupling with electric field and exciton-exciton
interaction, at the cost that the optical dipole is substantially quenched (by
several orders of magnitude). In this letter, we demonstrate the ability to
create a new class of excitons in transition metal dichalcogenide (TMD) hetero-
and homo-bilayers that combines the advantages of monolayer- and
interlayer-excitons, i.e. featuring both large optical dipole and large
electric dipole. These excitons consist of an electron that is well confined in
an individual layer, and a hole that is well extended in both layers, realized
here through the carrier-species specific layer-hybridization controlled
through the interplay of rotational, translational, band offset, and
valley-spin degrees of freedom. We observe different species of such
layer-hybridized valley excitons in different heterobilayer and homobilayer
systems, which can be utilized for realizing strongly interacting
excitonic/polaritonic gases, as well as optical quantum coherent controls of
bidirectional interlayer carrier transfer either with upper conversion or down
conversion in energy
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