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Use Intention of Chauffeured Car Services by O2O and Sharing Economy (공유경제와 O2O를 활용한 Chauffeured Car Services의 이용의도에 관한 연구)

  • Tian, Xiu-Fu;Wu, Run-Ze;Lee, Jong-Ho
    • Journal of Distribution Science
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    • v.15 no.12
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    • pp.73-84
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    • 2017
  • Purpose - Over recent years, O2O and shared economy have been an eye-catching topic. Many researches on O2O and shared economy have been published gradually. The emerging enterprise of chauffeured car services developed rapidly in the past two years. Therefore, it is necessary to explore the influencing factors of use intention of the chauffeured car services users. Through active use of O2O and shared economy, put up with operation strategy in line with their use intention. Research design, data, and methodology - After collecting 324 respondents in China with questionnaires, this study begin the empirical research with users of Chauffeured Car Services, and analyzes data with IBM SPSS 24.0 and IBM AMOS 24.0. Results - Personal Propensity to Trust significantly affects the Initial Trust of chauffeured car services users. Firm Reputation significantly affects the Initial Trust and use intention of chauffeured car services users. Initial Trust significantly affects the use intention of chauffeured car services users. Performance Expectancy and Effort Expectancy significantly affect chauffeured car services users' use intention. Social Influence also significantly affects the use intention of chauffeured car services users. Conclusions - First, Initial Trust significantly affects the use intention of chauffeured car services users. Thus, the enterprise should make efforts to improve users' initial trust in order to attract their attention. For this reason, chauffeured car services enterprises should conduct questionnaires to deeply explore what needs can improve users' initial trust. Second, performance expectancy and effort expectancy significantly affect chauffeured car services users' use intention. When users enjoy chauffeured car services, they attach great importance to the convenience, simplicity and efficiency, which reflects that chauffeured car services' desire for greater development in the O2O and shared economy market. Therefore, they need to grasp users' needs (convenience, simplicity and efficiency) and carefully improve the quality of chauffeured car services. Finally, social influence also significantly affects the use intention of chauffeured car services users. It means friend recommendation or mass media influences users' intention. So, it is more important to increase differentiated benefits, advertising and publicity of chauffeured car services.

Clinical Study of Tumor Angiogenesis and Perfusion Imaging Using Multi-slice Spiral Computed Tomography for Breast Cancer

  • Xu, Na;Lei, Zhen;Li, Xiao-Long;Zhang, Jun;Li, Chen;Feng, Guo-Quan;Li, Di-Nuo;Liu, Jing-Yi;Wei, Qiang;Bian, Ting-Ting;Zou, Tian-Yu
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.1
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    • pp.429-433
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    • 2013
  • Objectives: To explore the correlation between multi-slice spiral CT (MSCT) perfusion parameters and the expression of vascular endothelial growth factor (VEGF) as well as matrix metalloproteinase-2 (MMP-2) in breast cancer. Methods: Forty five breast cancer patients and 16 patients with benign breast tumor, both confirmed by pathology examination, were enrolled. All underwent MSCT perfusion imaging to obtain perfusion maps and data for parameters including blood flow (BF), blood volume (BV) and permeability surface (PS). Cancer patients did not receive treatment prior to surgery. The expression of VEGF and MMP-2 were examined with both immunohistochemistry and Western blotting. Results: The levels of VEGF and MMP-2 by immunohistochemistry were significantly higher in the breast cancer group (P < 0.01) than the benign tumor group. Relative OD values from Western blotting were also higher in cancer cases (P < 0.05). Similarly, the mean MSCT perfusion parameters (BF, BV, PS) were significantly higher in the breast cancer group (P < 0.01), BF and BV positively correlating with VEGF expression (r = 0.878 and 0.809 respectively, P < 0.01); PS and VEGF and MMP-2 expression were also positively correlated (r= 0.860, 0.786 respectively, P < 0.01). Conclusion: There is a correlation between breast cancer MSCT perfusion parameters and VEGF andMMP-2 expression, which might be useful for detection of breast lesions, qualitative diagnosis of breast cancer, and evaluation of breast cancer treatment.

Effects of Differential Distribution of Microvessel Density, Possibly Regulated by miR-374a, on Breast Cancer Prognosis

  • Li, Jian-Yi;Zhang, Yang;Zhang, Wen-Hai;Jia, Shi;Kang, Ye;Tian, Rui
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.3
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    • pp.1715-1720
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    • 2013
  • Background: The discovery that microRNAs (miRNAs) regulate proliferation, invasion and metastasis provides a principal molecular basis of tumor heterogeneity. Microvessel distribution is an important characteristic of solid tumors, with significant hypoxia occurring in the center of tumors with low blood flow. The distribution of miR-374a in breast tumors was examined as a factor likely to be important in breast cancer progression. Methods: Breast tissue samples from 40 patients with breast cancer were classified into two groups: a highly invasive and metastatic group (HIMG) and a low-invasive and metastatic Group (LIMG). Samples were collected from the center and edge of each tumor. In each group, six specimens were examined by microRNA array, and the remaining 14 specimens were used for real-time RT-qPCR, Western blot and immunohistochemical analyses. Correlation analysis was performed for the miRNAs and target proteins. Follow-up was carried out during 28 months to 68 months after surgery, and survival data were analyzed. Results: In the LIMG, the relative content of miR-374a was lower in the center of the tumor than at its edge; in the HIMG, it was lower at the edge of the tumor, and miR-374a levels were lower in breast cancer tissues than in normal tissues. There was no difference between VEGF-A and VCAM-1 mRNA levels at the edge and center of the tumor; however, we observed a significant difference between VEGF-A and VCAM-1 protein expression levels in these two regions. There was a negative correlation between miR-374a and target protein levels. The microvessel density (MVD) was lower in the center of the tumor than at its edge in HIMG, but the LIMG vessels were uniformly distributed. There was a significant positive correlation between MVD and the number of lymph node metastases (Pearson correlation, r=0.912, P<0.01). The median follow-up time was 48.5 months. LIMG had higher rate of disease-free survival (100%, P=0.013) and longer median survival time (66 months) than HIMG, which had a lower rate of 75% and shorter median survival time (54 months). Conclusions: Our data demonstrated miR-374a to be differentially distributed in breast cancer; VEGF-A and VCAM-1 mRNA had coincident distribution, and the distribution of teh respective proteins was uneven and opposite to that for the miR-374a. These data might explain the differences in the distribution of MVD in breast cancer and variation in breast cancer prognosis.

Measurement of Solubilities in the Ternary System NaCl + CaCl2 + H2O and KCl + CaCl2 + H2O at 50℃ (NaCl + CaCl2 + H2O 및 KCl + CaCl2 + H2O 삼성분계에 대한 50℃에서의 용해도 측정)

  • Yang, Ji-Min;Hou, Guang-Yue;Ding, Tian-Rong;Kou, Peng
    • Journal of the Korean Chemical Society
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    • v.54 no.3
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    • pp.269-274
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    • 2010
  • The solubility and the physicochemical property (refractive index) in the NaCl-$CaCl_2$-$H_2O$ and KCl-$CaCl_2$-$H_2O$ systems were determined at $50^{\circ}C$ and the phase diagrams and the diagrams of physicochemical property vs composition were plotted. One invariant point, two univariant curves, and two crystallization zones, corresponding to sodium Chloride (or potassium chloride), dihydrate ($CaCl_2{\cdot}2H_2O$) showed up in the phase diagrams of the ternary systems. The mixing parameters ${\theta}_{M,Ca}$ and ${\Psi}_{M,Ca,Cl}$ (M = Na or K) and equilibrium constant $K_{sp}$ were evaluated in NaCl-$CaCl_2-H_2O$ and KCl-$CaCl_2-H_2O$ systems by least-squares optimization procedure, in which the single-salt Pitzer parameters of NaCl, KCl and $CaCl_2$ ${\beta}^{(0)}$, ${\beta}^{(1)}$, ${\beta}^{(2)}$ and $C^{\Phi}$ were directly calculated from the literature. The results obtained were in good agreement with the experimental data.

Hybrid medium model for conjugate heat transfer modeling in the core of sodium-cooled fast reactor

  • Wang, X.A.;Zhang, Dalin;Wang, Mingjun;Song, Ping;Wang, Shibao;Liang, Yu;Zhang, Yapei;Tian, Wenxi;Qiu, Suizheng;Su, G.H.
    • Nuclear Engineering and Technology
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    • v.52 no.4
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    • pp.708-720
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    • 2020
  • Core-wide temperature distribution in sodium-cooled fast reactor plays a key role in its decay heat removal process, however the prediction for temperature distribution is quite complex due to the conjugate heat transfer between the assembly flow and the inter-wrapper flow. Hybrid medium model has been proposed for conjugate heat transfer modeling in the core. The core is modeled with a Realistic modeled inter-wrapper flow and hybrid medium modeled assembly flow. To validate present model, simulations for a three-assembly model were performed with Realistic modeling, traditional porous medium model and hybrid medium model, respectively. The influences of Uniform/Non-Uniform power distribution among assemblies and the Peclet number within the assembly flow have been considered. Compared to traditional porous medium model, present model shows a better agreement with in Realistic modeling prediction of the temperature distribution and the radial heat transfer between the inter-wrapper flow and the assembly flow.

Prediction of dryout-type CHF for rod bundle in natural circulation loop under motion condition

  • Huang, Siyang;Tian, Wenxi;Wang, Xiaoyang;Chen, Ronghua;Yue, Nina;Xi, Mengmeng;Su, G.H.;Qiu, Suizheng
    • Nuclear Engineering and Technology
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    • v.52 no.4
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    • pp.721-733
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    • 2020
  • In nuclear engineering, the occurrence of critical heat flux (CHF) is complicated for rod bundle, and it is much more difficult to predict the CHF when it is in natural circulation under motion condition. In this paper, the dryout-type CHF is investigated for the rod bundle in a natural circulation loop under rolling motion condition based on the coupled analysis of subchannel method, a one-dimensional system analysis method and a CHF mechanism model, namely the three-fluid model for annular flow. In order to consider the rolling effect of the natural circulation loop, the subchannel model is connected to the one-dimensional system code at the inlet and outlet of the rod bundle. The subchannel analysis provides the local thermal hydraulic parameters as input for the CHF mechanism model to calculate the occurrence of CHF. The rolling motion is modeled by additional motion forces in the momentum equation. First, the calculation methods of the natural circulation and CHF are validated by a published natural circulation experiment data and a CHF empirical correlation, respectively. Then, the CHF of the rod bundle in a natural circulation loop under both the stationary and rolling motion condition is predicted and analyzed. According to the calculation results, CHF under stationary condition is smaller than that under rolling motion condition. Besides, the CHF decreases with the increase of the rolling period and angular acceleration amplitude within the range of inlet subcooling and mass flux adopted in the current research. This paper can provide useful information for the prediction of CHF in natural circulation under motion condition, which is important for the nuclear reactor design improvement and safety analysis.

Simulation on mass transfer at immiscible liquid interface entrained by single bubble using particle method

  • Dong, Chunhui;Guo, Kailun;Cai, Qinghang;Chen, Ronghua;Tian, Wenxi;Qiu, Suizheng;Su, G.H.
    • Nuclear Engineering and Technology
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    • v.52 no.6
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    • pp.1172-1179
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    • 2020
  • As a Lagrangian particle method, Moving Particle Semi-implicit (MPS) method has great capability to capture interface/surface. In recent years, the multiphase flow simulation using MPS method has become one of the important directions of its developments. In this study, some key methods for multiphase flow have been introduced. The interface tension model in multiphase flow is modified to maintain the smooth of the interface and suitable for the three-phase flow. The mass transfer at immiscible liquid interface entrained by single bubble which could occur in Molten Core-Concrete Interaction (MCCI) has been investigated using this particle method. With the increase of bubble size, the height of entrainment column also increases, but the time of film rupture is slightly different. With the increase of density ratio between the two liquids, the height of entrained column decreases significantly due to the decreasing buoyancy of the denser liquid in the lighter liquid. In addition, the larger the interface tension coefficient is, the more rapidly the entrained denser liquid falls. This study validates that the MPS method has shown great performance for multiphase flow simulation. Besides, the influence of physical parameters on the mass transfer at immiscible interface has also been investigated in this study.

CFD simulation of flow and heat transfer characteristics in a 5×5 fuel rod bundles with spacer grids of advanced PWR

  • Wang, Yingjie;Wang, Mingjun;Ju, Haoran;Zhao, Minfu;Zhang, Dalin;Tian, Wenxi;Liu, Tiancai;Qiu, Suizheng;Su, G.H.
    • Nuclear Engineering and Technology
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    • v.52 no.7
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    • pp.1386-1395
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    • 2020
  • High fidelity nuclear reactor fuel assembly simulation using CFD method is an effective way for the structure design and optimization. The validated models and user practice guidelines play critical roles in achieving reliable results in CFD simulations. In this paper, the international benchmark MATiS-H is studied carefully and the best user practice guideline is achieved for the rod bundles simulation. Then a 5 × 5 rod bundles model in the advanced pressurized water reactor (PWR) is established and the detailed three-dimensional thermal-hydraulic characteristics are investigated. The influence of spacer grids and mixing vanes on the flow and hear transfer in rod bundles is revealed. As the coolant flows through the spacer grids and mixing vanes in the rod bundles, the drastic lateral flow would be induced and the pressure drop increases significantly. In addition, the heat transfer is enhanced remarkably due to the strong mixing effects. The calculation results could provide meaningful guidelines for the design of advanced PWR fuel assembly.

Increment of Physiologically Active Compounds in Germinated Brown Rice Treated with Chitosan and its Effect on Obesity of Rat Fed a High Fat Diet (키토산을 처리한 발아현미의 기능성분 증대 및 비만에 미치는 영향)

  • Li, Hua;Cho, Jeong-Yong;Gao, Tian-Cheng;Choi, Cha-Ran;Lee, Kang-Deok;Cho, Ji-Eun;Cho, Geon-Sik;Ham, Kyung-Sik
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.37 no.8
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    • pp.985-991
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    • 2008
  • This study was to investigated the changes of physiologically active components in germinated brown rice treated with chitosan (CGBR) and its anti-obesity effect in rat fed a high fat diet. Contents of physiologically active compounds such as total phenolic compounds, total dietary fiber, $\gamma$-aminobutyric acid (GABA), and total phytic acid in CGBR were significantly higher than those of traditional germinated brown rice (GBR). Lipase inhibitory activity of CGBR was higher than those of GBR and brown rice (BR). High fat diets containing CGBR, GBR, and BR were administered to three groups of male Sprague-Dawley rats for four weeks. All groups showed no significant difference in body weight, total abdominal fat, and plasma lipid levels. However, CGBR group appeared to have lower body weight gain and total abdominal fat level than other groups fed high fat diets containing GBR and BR. Total cholesterol and LDL-cholesterol contents in plasma of CGBR group were also lower than those of other groups. Thus, new germination method of brown rice using chitosan is a useful process, which utilizes plant defense responses to elevate the production of secondary metabolites and anti-obesity effect.

Hypertonicity Down-regulates the $1{\alpha},25(OH)_2$ Vitamin $D_3$-induced Osteoclastogenesis Via the Modulation of RANKL Expression in Osteoblast

  • Jeong, Hyun-Joo;Yushun, Tian;Kim, Bo-Hye;Nam, Mi-Young;Lee, Hyun-A;Yoo, Yun-Jung;Seo, Jeong-Taeg;Shin, Dong-Min;Ohk, Seung-Ho;Lee, Syng-Ill
    • International Journal of Oral Biology
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    • v.30 no.1
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    • pp.23-30
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    • 2005
  • Bone remodeling is a process controlled by the action of two major bone cells; the bone forming osteoblast and the bone resorbing osteoclast. In the process of osteoclastogenesis, stromal cells and osteoblast produce RANKL, OPG, and M-CSF, which in turn regulate the osteoclastogenesis. During the bone resorption by activated osteoclasts, extracellular $Ca^{2+}/{PO_4}^{2-}$ concentration and degraded organic materials goes up, providing the hypertonic microenvironment. In this study, we tested the effects of hypertonicity due to the degraded organic materials on osteoclastogenesis in co-culture system. It was examined the cellular response of osteoblastic cell in terms of osteoclastogenesis by applying the sucrose, and mannitol, as a substitute of degraded organic materials to co-culture system. Apart from the sucrose, mannitol, and NaCl was tested to be compared to the effect of organic osmotic particles. The addition of sucrose and mannitol (25, 50, 100, 150, or 200 mM) to co-culture medium inhibited the number of tartrate-resistant acid phosphatase (TRAP) positive multinucleated cells induced by 10 nM $1{\alpha},25(OH)_2vitaminD_3$ ($1{\alpha},25(OH)_2D_3$). However, NaCl did exert harmful effect upon the cells in this co-culture system, which is attributed to DNA damage in high concentration of NaCl. To further investigate the mechanism by which hypertonicity inhibits $1{\alpha},25(OH)_2D_3$-induced osteoclastogenesis, the mRNA expressions of receptor activator of nuclear factor (NF)-kB ligand (RANKL) and osteoprotegerin (OPG) were monitored by RT-PCR. In the presence of sucrose (50 mM), RANKL mRNA expression was decreased in a dose-dependent manner, while the change in OPG and M-CSF mRNA were not occurred in significantly. The RANKL mRNA expression was inhibited for 48 hours in the presence of sucrose (50 mM), but such a decrement recovered after 72 hours. However, there were no considerable changes in the expression of OPG and M-CSF mRNA. Conclusively, these findings strongly suggest that hypertonic stress down-regulates $1{\alpha},25(OH)_2D_3$-induced osteoclastogenesis via RANKL signal pathway in osteoblastic cell, and may playa pivotal role as a regulator that modulates osteoclastogenesis.