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Search Results: 1 - 10 of 61101 matches for " Lipeng Yu "
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Association of Gln27Glu and Arg16Gly Polymorphisms in Beta2-Adrenergic Receptor Gene with Obesity Susceptibility: A Meta-Analysis
Hongxiu Zhang, Jie Wu, Lipeng Yu
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0100489
Abstract: Background The beta2-adrenergic receptor (ADRB2) gene polymorphism has been implicated in susceptibility to obesity, but study results are still controversial. Objective The present meta-analysis is performed to determine whether there are any associations between the Gln27Glu (rs1042714) or the Arg16Gly (rs1042713) polymorphisms in ADRB2 and obesity susceptibility. Methods The PubMed (1950–2014), Embase (1974–2014), and China National Knowledge Infrastructure (CNKI, 1994–2014) databases were searched using the search terms (“Beta2-adrenergic receptor”, “β2-adrenergic receptor” or “ADRB2”), “polymorphism,” and “obesity”. Fixed- or random-effects pooled measures were determined on the bias of heterogeneity tests across studies. Publication bias was examined by Egger's test and the modified Begg's test. Results Eighteen published articles were selected for meta-analysis. Overall analyses showed that rs1042714 (Gln27Glu) was associated with significantly increased obesity risk in the heterozygote model (Gln/Glu vs. Gln/Gln: OR: 1.16, 95% CI: 1.04–1.30, I2 = 49%, P = 0.009) and the dominant model (Gln/Glu + Glu/Glu vs. Gln/Gln: OR: 1.2, 95% CI: 1.00–1.44, I2 = 55%, P = 0.04), whereas no significant association was found in the other models for rs1042714. Also, no significant association was found between the rs1042713 (Arg16Gly) gene polymorphism and the risk of obesity in all genetic models. In addition, neither rs1042713 (Arg16Gly) nor rs1042714 (Gln27Glu) showed any significant association with obesity susceptibility when the population were stratified based on gender. Conclusion Our meta-analysis revealed that the rs1042714 (Gln27Glu) polymorphism is associated with obesity susceptibility. However, our results do not support an association between rs1042713 (Arg16Gly) polymorphisms and obesity in the populations investigated. This conclusion warrants confirmation by more case-control and cohort studies.
Curvature Singularity in the Asymmetric Breakup of an Underwater Air Bubble
Lipeng Lai
Physics , 2012, DOI: 10.1063/1.4758280
Abstract: The presence of slight azimuthal asymmetry in the initial shape of an underwater bubble entirely alters the final breakup dynamics. Here I examine the influence of initial asymmetry on the final breakup by simulating the bubble surface evolution as a Hamiltonian evolution corresponding to an inviscid, two-dimensional, planar implosion. I find two types of breakups: a previously reported coalescence mode in which distant regions along the air-water surface curve inwards and eventually collide with finite speed, and a hitherto unknown cusp-like mode in which the surface develops sharp tips whose radii of curvature are much smaller than the average neck radius. I present three sets of results that characterize the nature of this cusp mode. First, I show that the cusp mode corresponds to a saddle-node. In other words, an evolution towards a cross-section shape with sharp tips invariably later evolves away from it. In phase space, this saddle-node separates coalescence modes whose coalescence planes lie along different spatial orientations. Second, I show that the formation of the sharp tips can be interpreted as a weakly first-order transition which becomes second-order, corresponding to the formation of a finite-time curvature singularity, in the limit that the initial perturbation amplitude approaches zero. Third I show that, as the curvature singularity is approached, the maximum surface curvature diverges approximately as $(t_c - t)^{-0.8}$, where $t_c$ is the onset time of the singularity and the maximum velocity diverges approximately as $(t_c-t)^{-0.4}$. In practice, these divergences imply that viscous drag and compressibility of the gas flow, two effects not included in my analysis, become significant as the interface evolves towards the curvature singularity.
An 8 bit 12 MS/s asynchronous successive approximation register ADC with an on-chip reference
8位12MS/s带片上参考电压的异步逐次逼近模数转换器

Yu Meng,Wu Lipeng,Li Fule,Wang Zhihua,
余萌
,吴礼鹏,李福乐,王志华

半导体学报 , 2013,
Abstract: 本文提出了一种应用于无线收发机的8位12MS/s 异步逐次逼近模数转换器。采用分段电容阵列数模转换器来缩减面积和功耗,并通过理论分析选取分段电容的值来确保线性度。本文优化的异步控制逻辑不仅避免了片上高速时钟,而且有效地加速了逐次逼近逻辑。采用全集成的参考和片上解耦电容的方式构成的参考电压,减少了片外参考所需的额外的引脚。芯片采用UMC 0.18μm CMOS工艺制造,在12MS/s采样频率时,测试有效位达到7.64bit。电路采用1.8V电压供电,整个芯片功耗为0.918mW,其中参考电压源部分消耗了53%。不包括参考消耗的功耗时,整个电路的FOM值达到180fJ/ conv.-step。
On the Cultivation of Automation Majors’ Research Innovation Ability Based on Scientific Research Projects
Lipeng Wang,Mingqiu Li
Higher Education Studies , 2012, DOI: 10.5539/hes.v2n4p137
Abstract: Currently, it has become a fundamental goal for the engineering major to cultivate high-quality engineering technicians with innovation ability in scientific research which is an important academic ability necessary for them. This paper mainly explores the development of comprehensive and designing experiments in automation based on scientific research projects and elaborates on the significance and indispensable role of these experiments in cultivating students’ research innovation ability.
Towards a Simple, Fast, Oscillation-free, High-resolution Algorithm for Convection-Dominated Flows: The Position-State Separation Method
Lipeng Liu,Marley Becerra
Physics , 2015,
Abstract: A simple, fast, oscillation-free, high-resolution algorithm for convection-dominated flows is proposed. The stability, accuracy and time complexity of this method called the position-state separation method (POSS) are discussed. Several classical numerical experiments in different dimensions and coordinate systems are conducted to demonstrate the excellent performance of the POSS regarding computational cost, robustness, and high-resolution. It is shown that the step time of POSS is not restricted by the CFL condition and that the time complexity of the method when dealing with the convection-dominated flows increases linearly with the number of unknowns.
Spectrins in Axonal Cytoskeletons: Dynamics Revealed by Extensions and Fluctuations
Lipeng Lai,Jianshu Cao
Quantitative Biology , 2013, DOI: 10.1063/1.4885720
Abstract: The macroscopic properties, the properties of individual components and how those components interact with each other are three important aspects of a composited structure. An understanding of the interplay between them is essential in the study of complex systems. Using axonal cytoskeleton as an example system, here we perform a theoretical study of slender structures that can be coarse-grained as a simple smooth 3-dimensional curve. We first present a generic model for such systems based on the fundamental theorem of curves. We use this generic model to demonstrate the applicability of the well-known worm-like chain (WLC) model to the network level and investigate the situation when the system is stretched by strong forces (weakly bending limit). We specifically studied recent experimental observations that revealed the hitherto unknown periodic cytoskeleton structure of axons and measured the longitudinal fluctuations. Instead of focusing on single molecules, we apply analytical results from the WLC model to both single molecule and network levels and focus on the relations between extensions and fluctuations. We show how this approach introduces constraints to possible local dynamics of the spectrin tetramers in the axonal cytoskeleton and finally suggests simple but self-consistent dynamics of spectrins in which the spectrins in one spatial period of axons fluctuate in-sync.
Metrics for matrix-valued measures via test functions
Lipeng Ning,Tryphon T. Georgiou
Computer Science , 2014,
Abstract: It is perhaps not widely recognized that certain common notions of distance between probability measures have an alternative dual interpretation which compares corresponding functionals against suitable families of test functions. This dual viewpoint extends in a straightforward manner to suggest metrics between matrix-valued measures. Our main interest has been in developing weakly-continuous metrics that are suitable for comparing matrix-valued power spectral density functions. To this end, and following the suggested recipe of utilizing suitable families of test functions, we develop a weakly-continuous metric that is analogous to the Wasserstein metric and applies to matrix-valued densities. We use a numerical example to compare this metric to certain standard alternatives including a different version of a matricial Wasserstein metric developed earlier.
HDAC Inhibitors Act with 5-aza-2′-Deoxycytidine to Inhibit Cell Proliferation by Suppressing Removal of Incorporated Abases in Lung Cancer Cells
Guolin Chai, Lian Li, Wen Zhou, Lipeng Wu, Ying Zhao, Donglai Wang, Shaoli Lu, Yu Yu, Haiying Wang, Michael A. McNutt, Ye-Guang Hu, Yingqi Chen, Yang Yang, Xin Wu, Gregory A. Otterson, Wei-Guo Zhu
PLOS ONE , 2008, DOI: 10.1371/journal.pone.0002445
Abstract: 5-aza-2′-deoxycytidine (5-aza-CdR) is used extensively as a demethylating agent and acts in concert with histone deacetylase inhibitors (HDACI) to induce apoptosis or inhibition of cell proliferation in human cancer cells. Whether the action of 5-aza-CdR in this synergistic effect results from demethylation by this agent is not yet clear. In this study we found that inhibition of cell proliferation was not observed when cells with knockdown of DNA methyltransferase 1 (DNMT1), or double knock down of DNMT1-DNMT3A or DNMT1-DNMT3B were treated with HDACI, implying that the demethylating function of 5-aza-CdR may be not involved in this synergistic effect. Further study showed that there was a causal relationship between 5-aza-CdR induced DNA damage and the amount of [3H]-5-aza-CdR incorporated in DNA. However, incorporated [3H]-5-aza-CdR gradually decreased when cells were incubated in [3H]-5-aza-CdR free medium, indicating that 5-aza-CdR, which is an abnormal base, may be excluded by the cell repair system. It was of interest that HDACI significantly postponed the removal of the incorporated [3H]-5-aza-CdR from DNA. Moreover, HDAC inhibitor showed selective synergy with nucleoside analog-induced DNA damage to inhibit cell proliferation, but showed no such effect with other DNA damage stresses such as γ-ray and UV, etoposide or cisplatin. This study demonstrates that HDACI synergistically inhibits cell proliferation with nucleoside analogs by suppressing removal of incorporated harmful nucleotide analogs from DNA.
Study on dynamic angle of repose for submarine pipeline with spoiler on sandy seabed
Lipeng Yang,Bing Shi,Yakun Guo
Journal of Petroleum Exploration and Production Technologies , 2012, DOI: 10.1007/s13202-012-0037-7
Abstract: This paper investigates the dynamic angle of repose underneath the submarine pipeline. A series of tests are carried out to explore the bottom velocity in the scour hole for the case of with spoiler, and gap-ratio in unidirectional current. On that basis, the formulas of dynamic angle of repose in the scour hole are proposed using a sand deposition model. The formulas consider the bottom velocity (which is mainly influenced by the spoiler height and gap-ratio) that dominates the angle of repose. The calculation results are verified by the test data and a good agreement is obtained.
A New Framework of the Unsupervised Classification for High-Resolution Remote Sensing Image
Penglin Zhang,Zhiyong Lv,Lipeng Gao
TELKOMNIKA : Indonesian Journal of Electrical Engineering , 2012, DOI: 10.11591/telkomnika.v10i7.1571
Abstract: Classification plays a significant role in change detection when monitoring the evolution of the Earth’s surface. This paper proposes a novel object-oriented framework for the unsupervised classification of high-resolution remote sensing images based on Jenks’ optimization. The fractal net evolution approach is employed as an image segmental technique, the spectral feature of each image object is extracted, and an algorithm of Jenks’ optimization is adopted as a classifier. Two experiments with different image platforms are conducted to evaluate the performance of the proposed framework and to compare with other traditional unsupervised classification algorithms such as the iterative self-organizing data analysis technique algorithm and k-means clustering algorithms. The proposed approach is found to be feasible and valid.
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