3,044 research outputs found

    The Mediating Role of Trust in the Relationship Between Online Shopping Experience and Consumer\u27s Shopping Values

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    A structural equation model is proposed and examined through a survey research. Data were collected from a survey of 121 subjects. The PLS (Partial Least Square) method was applied to estimate the research models. One model included the trust variable as a mediator and the other excluded it. The comparison of R2 verified that the first model had a better fit. The results of the study show the level of experience has a significant impact on both utilitarian and hedonic shopping values in the case of the model without the mediator. However, experience has an insignificant or a partially significant effect on utilitarian and hedonic shopping values when trust mediates experience and shopping values. This study verifies a mediating role of trust in the relationship between experience and shopping values. Finally, the implications and limitations are further discussed

    Factors Motivating Software Piracy in Vietnam

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    This research focuses on the development and empirical validation of a model of software piracy behavior in Vietnam on the basis of institution isomorphism theory, deterrence theory, and expected utility theory. A survey of 145 respondents and PLS (Partial Least Square) were utilized for analysis. The test of this study reveals that mimetic pressure is the greatest significant factor to influence software piracy intention. Coercive pressure, normative pressure, punishment severity, and software cost are also significantly related to the intention. However, punishment certainty does not have a significant influence on software piracy

    The uncalibrated pulse contour cardiac output during off-pump coronary bypass surgery: performance in patients with a low cardiac output status and a reduced left ventricular function

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    BACKGROUND: We compared the continuous cardiac index measured by the FloTrac/Vigileoā„¢ system (FCI) to that measured by a pulmonary artery catheter (CCI) with emphasis on the accuracy of the FCI in patients with a decreased left ventricular ejection fraction (LVEF) and a low cardiac output status during off-pump coronary bypass surgery (OPCAB). We also assessed the influence of several factors affecting the pulse contour, such as the mean arterial pressure (MAP), the systemic vascular resistance index (SVRI) and the use of norepinephrine. METHODS: Fifty patients who were undergoing OPCAB (30 patients with a LVEF ā‰„ 40%, 20 patients with a LVEF < 40%) were enrolled. The FCI and CCI were measured and we performed a Bland-Altman analysis. Subgroup analyses were done according to the LVEF (< 40%), the CCI (ā‰¤ 2.4 L/min/m), the MAP (60-80 mmHg), the SVRI (1,600-2,600 dyne/s/cm(5)/m(2)) and the use of norepinephrine. RESULTS: The FCI was reliable at all the time points of measurement with an overall bias and limit of agreement of -0.07 and 0.67 L/min/m(2), respectively, resulting in a percentage error of 26.9%. The percentage errors in the patients with a decreased LVEF and in a low cardiac output status were 28.2% and 22.3%, respectively. However, the percentage error in the 91 data pairs outside the normal range of the SVRI was 40.2%. CONCLUSIONS: The cardiac output measured by the FloTrac/Vigileoā„¢ system was reliable even in patients with a decreased LVEF and in a low cardiac output status during OPCAB. Acceptable agreement was also noted during the period of heart displacement and grafting of the obtuse marginalis branch.ope

    Fabrication and photoluminescent characteristics of ZnO/Mg0.2Zn0.8O coaxial nanorod single quantum well structures

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    The authors report on fabrication and photoluminescent (PL) properties of ZnO/Mg0.2Zn0.8O coaxial nanorod quantum structures with various quantum well and barrier layer thicknesses. Employing catalyst-free metal-organic vapor-phase epitaxy, coaxial nanorod single quantum well structures were fabricated by the alternate heteroepitaxial growth of ZnO and Mg0.2Zn0.8O layers over the entire surfaces of the ZnO nanorods with fine thickness controls of the layers. The quantum confinement effect of carriers in coaxial nanorod quantum structures depends on the Mg0.2Zn0.8O quantum barrier layer thickness as well as the thickness of the ZnO quantum well layer. The temperature-dependent PL characteristics of the coaxial nanorod quantum structures are also discussed.This work was financially supported under the National Creative Research Initiative Project by the KOSEF

    Hydrogen effects on nanoindentation behavior of metallic glass ribbons

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    Recently, metallic glass (MG) membranes that are permeable to hydrogen have gained interest due to the increasing importance of hydrogen separation in a number of applications, e.g., hydrogen-powered fuel cells. An important issue in the context of MG membranes is the hydrogen-induced embrittlement and efforts to understand the role played by hydrogen in the mechanical properties, especially yielding and plastic deformation behavior, of MGs are being made. In this study, therefore, an attempt was made by performing nanoindentation tests with cube-corner and spherical indenter tips on a series of Niā€“Nbā€“Zr amorphous alloy ribbons to investigate the hydrogen effects on nanohardness and pop-in behavior (Figure 1). Weight gain measurements after hydrogen charging and thermal desorption spectroscopy (TDS) studies (Figure 2) were utilized to identify how the total hydrogen is partitioned into mobile and immobile parts. These, in turn, indicate the significant role of hydrogen mobility in the amorphous structure on the mechanical properties. In high-Zr alloys containing immobile H, both hardness (H) and shear yielding stress (Ļ„max) increase significantly; while in low-Zr alloys having only mobile hydrogen, decrease in hardness and Ļ„max were noted (Figure 1). The changes in shear transformation zone (STZ) volume, estimated through cumulative analysis of Ļ„max, caused by hydrogen absorption were also found to depend on hydrogen mobility such that immobile hydrogen reduces the STZ volume while mobile hydrogen increases it. *This research was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (No. 2013R1A1A2A10058551)

    Production of Transgenic Cloned Miniature Pigs with Membrane-bound Human Fas Ligand (FasL) by Somatic Cell Nuclear Transfer

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    Cell-mediated xenograft rejection, including NK cells and CD8+ CTL, is a major obstacle in successful pig-to-human xenotransplantation. Human CD8+ CTL and NK cells display high cytotoxicity for pig cells, mediated at least in part by the Fas/FasL pathway. To prevent cell-mediated xenocytotoxicity, a membrane-bound form of human FasL (mFasL) was generated as an inhibitor for CTL and NK cell cytotoxicity that could not be cleaved by metalloproteinase to produce putative soluble FasL. We produced two healthy transgenic pigs harboring the mFasL gene via somatic cell nuclear transfer (SCNT). In a cytotoxicity assay using transgenic clonal cell lines and transgenic pig ear cells, the rate of CD8+ CTL-mediated cytotoxicity was significantly reduced in transgenic pig&#x27;s ear cells compared with that in normal minipig fetal fibroblasts. Our data indicate that grafts of transgenic pigs expressing membrane-bound human FasL control the cellular immune response to xenografts, creating a window of opportunity to facilitate xenograft survival

    Effect of the prosthesisā€“patient mismatch on long-term clinical outcomes after isolated aortic valve replacement for aortic stenosis: AĀ prospective observational study

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    BackgroundThe effect of prosthesisā€“patient mismatch (PPM) on clinical outcomes after aortic valve replacement remains controversial. We evaluated effect of PPM on long-term clinical outcomes after isolated aortic valve replacement in patients with predominant aortic stenosis.MethodsWe analyzed data from patients with predominant aortic stenosis who underwent isolated aortic valve replacement between January 1995 and July 2010. The indexed effective orifice area, obtained by dividing the inĀ vivo effective orifice area by the patientā€™s body surface area, was used to define PPM as clinically nonsignificant (group I, 224 patients), mild (group II, 52 patients), moderate (group III, 39 patients), and severe (group IV, 36 patients).ResultsEarly survival was not significantly different among the groups, but overall survival was decreased gradually in group IV. Overall survival at 12 years was lower in group IV than in group I (92.8% Ā± 2.7% vs 67.0 Ā± 10.1, respectively; PĀ =Ā .001). Cardiac-related-death-free survival at 12 years was lower in patients with severe PPM. Left ventricular mass index decreased during the follow-up period in all groups. But left ventricular mass index was less decreased in group IV compared with groups I, II, and III. Age, severe PPM, and ejection fraction <40%, and New York Heart Association Functional Class IV were independent risk factors of overall survival on multivariate analysis. Severe PPM was an independent risk factor for cardiac-related death.ConclusionsSevere PPM showed an adverse effect on long-term survival, and was an independent risk factor for cardiac-related death. In addition, patients with severe PPM showed less decreasing left ventricular mass index during follow-up

    Clinical Characteristics and Risk Factors for Nosocomial Candidemia in Medical Intensive Care Units: Experience in a Single Hospital in Korea for 6.6 Years

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    The aim of this study was to determine candidemia incidence among patients in a medical intensive-care unit (MICU) and the associated mortality rate and to identify risk factors associated with candidemia. We retrospectively performed a 1:3 matched case-control study of MICU patients with candidemia. Controls were matched for sex, age, and Acute Physiology and Chronic Health Evaluation (APACHE) II score. Candidemia incidence was 9.1 per 1,000 admissions. The most common pathogen was Candida albicans. Crude mortality was 96% among candidemia patients and 52% among controls (P<0.001). Mortality differed significantly between the groups according to Kaplan-Meier survival analysis (P=0.024). Multivariate analysis identified the following independent risk factors for candidemia: central venous catheterization (odds ratio [OR] = 3.2, 95% confidence interval [CI]=1.2-9.0), previous steroid therapy (OR=4.7, 95% CI=1.8-12.1), blood transfusion during the same admission period (OR=6.3, 95% CI=2.4-16.7), and hepatic failure upon MICU admission (OR=6.9, 95% CI=1.7-28.4). In conclusion, we identify an additional independent risk factor for candidemia, the presence of hepatic failure on MICU admission. Therefore, increased awareness of risk factors, including hepatic failure, is necessary for the management of candidemia
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