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- Fan, Jing-yu, 1972, et al.
(author)
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Large-eddy simulation of three-dimensional vortical structures for an impinging transverse jet in the near region
- 2007
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In: Shuidonglixue Yanjiu yu Jinzhan / Journal of Hydrodynamics Ser. A. - : Springer Science and Business Media LLC. - 1000-4874. ; 19:3, s. 314-321
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Journal article (peer-reviewed)abstract
- The three-dimensional vortical structures for an impinging transverse jet in the near region were numerically investigated by means of Large-Eddy Simulation (LES). The LES results reproduced the skewed jet shear layer vortices close to the jet nozzle and the scarf vortex in the near-wall zone, in good agreement with the experimental observations. Different vortical modes in the skewed jet shear layer close to the jet nozzle were identified depending upon the velocity ratio between jet and crossflow, namely changing from an approximately axisymmetric mode to a helical one with the velocity ratios varying from 20 to 8. Moreover, the scarf vortex wrapped around the impinging jet in the near-wall zone showed distinct asymmetry with regard to its bilateral spiral legs within the near region. And the entrainment of the ambient crossflow fluids by the scarf vortex in the near-wall zone was appreciably influenced by its asymmetry and in a large part occurred on the surface of the spiral roller structures in the course of spreading downstream.
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- He, Lu-Jun, et al.
(author)
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Genetic polymorphisms of N-acetyltransferase 2 and colorectal cancer risk.
- 2005
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In: World Journal of Gastroenterology. - 1007-9327 .- 2219-2840. ; 11:27, s. 4268-4271
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Journal article (peer-reviewed)abstract
- AIM: To identify the distribution of N-acetyltrasferase 2(NAT2) polymorphism in Hebei Han Chinese and the effects of the polymorphism on the development of colorectal cancer. METHODS: We performed a hospital-based case-control study of 237 healthy individuals and 83 colorectal cancer patients of Hebei Han Chinese. DNA was extracted from peripheral blood and cancer tissues. The genotypes of the polymorphisms were assessed by PCR-restriction fragment length polymorphism (RFLP). RESULTS: There were four NAT2 alleles of WT, M1, M2, and M3 both in the healthy subjects and in the patients, and 10 genotypes of WT/WT, WT/M1, WT/M2, WT/M3, M1/M1, M1/M2, M1/M3, M2/M2, M2/M3, M3/M3. M2 allele was present in 15.61% of healthy subjects and 29.52% of patients (chi(2) = 15.31, P<0.0001), and M3 allele was present in 30.59% of healthy subjects and 16.87% of patients (chi(2) = 25.33, P<0.0001). There were more WT/M2 (chi(2) = 34.42, P<0.0001, odd ratio = 4.99, 95%CI = 2.27-9.38) and less WT/M3 (chi(2) = 3.80, P = 0.03) in the patients than in the healthy subjects. In 70.3% of the patients, there was a difference in NAT2 genotype between their tumors and blood cells. Patients had more WT/M2 (chi(2) = 5.11, P = 0.02) and less M2/M3 (chi(2) = 4.27, P = 0.039) in their blood cells than in the tumors. Furthermore, 53.8% (7/13) of M2/M3 in tumors were from WT/M2 of blood cells. CONCLUSION: There is a possible relationship between the NAT2 polymorphisms and colorectal cancer in Hebei Han Chinese. The genotype WT/M2 may be a risk factor for colorectal cancer.
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- Wang, Lin, et al.
(author)
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Synthesis and high pressure induced amorphization of C60 nanosheets
- 2007
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In: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 91:10, s. 103112-
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Journal article (peer-reviewed)abstract
- C-60 nanosheets with thicknesses in the nanometer range were synthesized by a simple method. Compared to bulk C-60, the lattice of the nanosheets is expanded by about 0.4%. In situ Raman spectroscopy and energy-dispersive x-ray diffraction under high pressures have been employed to study the structure of the nanosheets. The studies indicate that the bulk modulus of the C-60 nanosheets is significantly larger than that of bulk C-60. The C-60 cages in nanosheets can persist at pressures over 30 GPa, 3 GPa higher than for bulk C-60. These results suggest that C-60 crystals in even small size will be a potential candidate of superhard materials.
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- Yu, Ji-Guo, et al.
(author)
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Investigation of gene expression in C(2)C(12) Myotubes following simvastatin application and mechanical strain
- 2009
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In: Journal of Atherosclerosis and Thrombosis. - 1880-3873 .- 1340-3478. ; 16:1, s. 21-29
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Journal article (peer-reviewed)abstract
- Aim: The 3-hydroxy-3methylgutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) are the most effective prescribed drugs for lowering serum cholesterol; however, although statins are extremely safe medications and have brought significant benefits to patients with hypercholesterolemia, they have been shown to produce myalgia, cramps, exercise intolerance and fatigue. The aim of the study was to investigate the molecular mechanisms that may mediate statin myopathy.Methods: We used DNA microarray analysis to examine the changes in gene expression profiles induced by 1 hour and 6 hours of statin treatment on differentiated C(2)C(12) myotubes. Four genes were selected for analysis at the protein level using Western blot analysis on myotubes treated with statin with or without additional mechanical stretching.Results: Eighty-five genes exhibited more than a 2-fold up- or down-regulation in expression, of which 46 have known biological functions related primarily to transmembrane transport, signal transduction, cell growth/maintenance, protein metabolism, or apoptosis. At protein level, three of the four proteins were induced (Adrb1, Socs4 and Cflar) and one was repressed (Birc4). Changes in protein expression largely mirrored the changes in their corresponding transcripts, although the fold-change was less dramatic. The addition of imposed muscle fiber stretching did not exacerbate the expression of these genes at the protein level with the exception of Cflar, a pro-apoptotic protein.Conclusion: These data suggested that alterations in the expressions of some statin-regulated genes could be causative factors for statin toxicity in muscle. Repression of the anti-apoptosis gene (Birc4) and activation of the pro-apoptosis gene (Cflar) indicated that cell death may play an important role in statin-induced myopathy.
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- Yue, Cong, et al.
(author)
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Numerical Investigation on the Effect of Filler Distribution on Effective Thermal Conductivity of Thermal Interface Material
- 2008
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In: 2008 International Conference on Electronic Packaging Technology and High Density Packaging, ICEPT-HDP 2008; Pudong, Shanghai; China; 28 July 2008 through 31 July 2008. - 9781424427406 ; , s. C1-10
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Conference paper (peer-reviewed)abstract
- Thermal interface materials have been widely adopted in the thermal management for electronics system. Most of the thermal interface materials are made of polymers with thermally conductive particles distributed inside to enhance the thermal conductivity. Thus it is essential to figure out the effective thermal conductivity of this composite material. In the present paper, a parameterized cubic cell model had been developed and implemented by the finite element method. The numerical simulations were carried out to investigate the effect of the filler distributions on the effective thermal conductivity of the thermal interface materials. The volume percentage loadings of the particles ranging from 13% to 74% had been considered, and different particle distribution patterns had also been analyzed. The simulation results were compared with the experimental data as well as other models. A fairly good agreement was obtained for the particle volume percentage loading under consideration, which verified the developed cubic cell model.
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- Zhang, Yan, 1976, et al.
(author)
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Homogenization Model Based on Micropolar Theory for the Interconnection Layer in Microsystem Packaging
- 2006
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In: Proceedings of the eight IEEE CPMT International Symposium on High Density Packaging and Component Failure Anlaysis (HDP´06). - 1424404886 ; , s. 166-170
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Conference paper (peer-reviewed)abstract
- The increase in microsystem packaging density sets the requiement for component sizes in the system to become smaller and smaller. The scale decrease makes the analysis more complicated as the corresponding resolution should be improved to a great extent. Interconnection in the system is a typical interface structure that widely appear in the packaing system, in which periodic microstructures may be included inside. A homogenization model is developed in this paper, which focuses on the interface behavior. The interface model based on micropolar theory provides a natural way to include the characteristic scale that can reflect the size effect of the considered structure. Computations are carried out as the numerical example of the model, and comparisons of this model with those of the convertional method show its validity and efficiency.
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- Zhu, Huiming, et al.
(author)
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Bayesian Analysis of a Stochastic Volatility Model Using Gibbs Sampling
- 2008
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In: Hunan Daxue Xuebao (Ziran Kexue Ban). - 1674-2974. ; 35:12
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Journal article (peer-reviewed)abstract
- After exploring the statistical structure of the stochastic volatility model, its likelihood functions concrete form is derived, and its parameters conjugate priors are constructed. Then, using the Bayesian theorem, the conditional posterior distributions are derived. In order to obtain the Baysian parameters estimators and their intervals, we develop a Markov chain Monte Carlo algorithm procedure with Gibbs sampling. Finally, using the Shanghai stocks comprehensive index and the Shenzhen stocks composition index, we give an empirical example to illustrate how to use the proposed method. This paper provides a new approach to establish Bayesian models for financial stochastic volatilities with random parameters.
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