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Search Results: 1 - 10 of 104593 matches for " XiaoHua Zhang "
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Genome-wide screens for effective siRNAs through assessing the size of siRNA effects
Xiaohua Zhang
BMC Research Notes , 2008, DOI: 10.1186/1756-0500-1-33
Abstract: Based on a recently proposed parameter, strictly standardized mean difference (SSMD), I propose an analytic method for genome-wide screens of effective siRNAs through assessing and testing the size of siRNA effects. Central to this method is the capability of SSMD in quantifying siRNA effects. This method has relied on normal approximation, which works only in the primary screens but not in the confirmatory screens. In this paper, I explore the non-central t-distribution property of SSMD estimates and use this property to extend the SSMD-based method so that it works effectively in either primary or confirmatory screens as well as in any HTS screens with or without replicates. The SSMD-based method maintains a balanced control of false positives and false negatives.The central interest in genome-wide RNAi research is the selection of effective siRNAs which relies on the development of analytic methods to measure the size of siRNA effects. The new analytic method for hit selection provided in this paper offers a good analytic tool for selecting effective siRNAs, better than current analytic methods, and thus may have broad utility in genome-wide RNAi research.Mean difference, fold change, percent inhibition, percent activity, percent viability, Z-score and their robust versions have been used to quantify effect size of an siRNA or a compound in HTS assays [1-7]. However, these metrics have issues in capturing data variability or being affected by sample size and hence cannot effectively assess the size of effect. The p-values from the Z-score method (or equivalently Mean ± k SD and its variant Median ± k MAD) and classical t-test have widely been used to evaluate the chance of including siRNAs with no specific impact [1,2,5-7]. However, it is mean difference that these methods aim to test, and it is well-known that mean difference cannot effectively measure the magnitude of impact. In addition, the p-value from the Z-score method or t-test is affected by both sample
On the Difference Equation
Ding Xiaohua,Zhang Rongyan
Advances in Difference Equations , 2008,
Abstract: We study a discrete delay Mosquito population equation. Firstly, we study the stability of the equilibria of the system and the existence of period-two bifurcation by analyzing the characteristic equation. Secondly, the direction and stability of the bifurcation are determined by using the normal form theory. Finally, some computer simulations are performed to illustrate the analytical results found.
On the Difference Equation xn+1=( ±xn+ 2xn ¢ ’1)e ¢ ’xn
Xiaohua Ding,Rongyan Zhang
Advances in Difference Equations , 2008, DOI: 10.1155/2008/876936
Abstract: We study a discrete delay Mosquito population equation. Firstly, we study the stability of the equilibria of the system and the existence of period-two bifurcation by analyzing the characteristic equation. Secondly, the direction and stability of the bifurcation are determined by using the normal form theory. Finally, some computer simulations are performed to illustrate the analytical results found.
Enhancement of Friction between Carbon Nanotubes: An Efficient Strategy to Strengthen Fibers
Xiaohua Zhang,Qingwen Li
Physics , 2009, DOI: 10.1021/nn901515j
Abstract: Interfacial friction plays a crucial role in the mechanical properties of carbon nanotube based fibers, composites, and devices. Here we use molecular dynamics simulation to investigate the pressure effect on the friction within carbon nanotube bundles. It reveals that the intertube frictional force can be increased by a factor of 1.5 ~ 4, depending on tube chirality and radius, when all tubes collapse above a critical pressure and when the bundle remains collapsed with unloading down to atmospheric pressure. Furthermore, the overall cross-sectional area also decreases significantly for the collapsed structure, making the bundle stronger. Our study suggests a new and efficient way to reinforce nanotube fibers, possibly stronger than carbon fibers, for usage at ambient conditions.
Manipulate the coiling and uncoiling movements of Lepidoptera proboscis by its conformation optimizing
Xiaohua Zhou,Shengli Zhang
Quantitative Biology , 2013,
Abstract: Many kinds of adult Lepidoptera insects possess a long proboscis which is used to suck liquids and has the coiling and uncoiling movements. Although experiments revealed qualitatively that the coiling movement is governed by the hydraulic mechanism and the uncoiling movement is due to the musculature and the elasticity, it needs a quantitative investigation to reveal how insects achieve these behaviors accurately. Here a quasi-one-dimensional (Q1D) curvature elastica model is proposed to reveal the mechanism of these behaviors. We find that the functions of internal stipes muscle and basal galeal muscle which locate at the bottom of proboscis are to adjust the initial states in the coiling and uncoiling processes, respectively. The function of internal galeal muscle which exists along proboscis is to adjust the line tension. The knee bend shape is due to the local maximal spontaneous curvature and is an advantage for nectar-feeding butterfly. When there is no knee bend, the proboscis of fruit-piercing butterfly is easy to achieve the piercing movement which induced by the increase of internal hydraulic pressure. All of the results are in good agreement with experiential observation. Our study provides a revelatory method to investigate the mechanical behaviors of other 1D biologic structures, such as proboscis of marine snail and elephant. Our method and results are also significant in designing the bionic devices.
The Research on the Cooperation and Coordination Game in Constructing Low-Carbon Green Oil Port  [PDF]
Houming Fan, Guosong Dong, Xiaonan Zhang, Xiaohua Li, Xia Liang
Low Carbon Economy (LCE) , 2012, DOI: 10.4236/lce.2012.31003
Abstract: Constructing low-carbon green oil port is not only beneficial to change the present situation of Chinese oil port which has pollution problems and many risks, but also to increase the economic efficiency and improve the ability of sustainable development of low-carbon green oil port. While coordinating the cooperative relationship between each related enterprises participated in the construction of oil port low-carbon green oil port, is the important segment to build a low-carbon green oil port. This paper adopted the static game model under the asymmetric circumstance to research cooperative relations of low-carbon green oil port between the oil port enterprises and other enterprises and achieved good research achievements. The study results can provide for oil port supply chain related enterprise whether you choose cooperative strategy with the theory basis and the reference for decision.
Present Situation and Prospective of Camellia Nut Shells Utilization  [PDF]
Jinping Zhang, Lisong Hu, Zhoulian Wang, Menghao Du, Xiaohua Yao
Open Journal of Forestry (OJF) , 2015, DOI: 10.4236/ojf.2015.57066
Abstract: With the rapid development of Camellia oleifera industry, more and more Camellia nut shells have been produced, leading to serious environmental pollution problem. This paper reviews the works on the characterization of the physical and chemical properties of Camellia nut shells, active ingredient extraction, its application in chemical production, growing media and animal feed and its properties as a biomass. Based on the review, we proposed a novel all-component high value application strategy to covert camellia nut shells into high value biomasses, which could realize waste recycling and environmental protection.
MicroRNA Let-7g and Atherosclerosis Plaque Stabilization  [PDF]
Rongping Yin, Chenlin Zhang, Yunying Hou, Xiaohua Wang
World Journal of Cardiovascular Diseases (WJCD) , 2017, DOI: 10.4236/wjcd.2017.72003
Vascular atherosclerotic vulnerable plaque rupture is the primary cause of acute myocardial infarctions and strokes. Thus, stabilization of vulnerable plaques is of important clinical endeavor to decrease the fatal risk of atherosclerosis. Inflammatory infiltration, apoptosis of endothelial cells (ECs) and vascular smooth muscle cells (VSMCs), destruction of extracellular matrix (ECM) or collagen, and neovascularization all contribute to the formation and stability of plaque. Let-7g, one miRNA of let-7 family, is related to retardation of the progress of vulnerable atherosclerosis plaque. First of all, let-7g induced preservation on vascular diseases through regulating on the intracellular Ca2+- activated protein kinase C-oxLDL-LOX-1 pathway, which resulted in reduced leukocyte adhesion to and migration across endothelium. Over expression of let-7g negatively regulated apoptosis in the ECs by targeting lectin-like oxidized LDL receptor-1(LOX-1)/CASP3 expression, therefore made the fibrous cap of plaque integrated and thick, increased the density of vascular atherosclerotic plaque. In addition, let-7g might stabilize the atherosclerotic plaque through other aspects. In this review, we focus on current and potential importance of let-7g on the stabilization of atherosclerosis plaque which might lead to the future development of an alternative strategy of CAD.
FTIR and Thermogravimetric Analysis of Three Kinds of Nutshells  [PDF]
Jinping Zhang, Yue Ying, Xuebin Li, Xiaohua Yao
Natural Resources (NR) , 2018, DOI: 10.4236/nr.2018.98019
Abstract: The main components and pyrolysis characteristics of Camellia oleifera Abel hells, Castanea mollissima Blume shells, and Castanea mollissima Blume shells were analyzed by using FTIR and thermogravimetric methods. The experimental results indicated that the main components of the three kinds of raw materials consisted of cellulose, hemicellulose, and lignin. The highest contents of hemicellulose, cellulose, and lignin were in Camellia oleiferaAbel shells (49.34% ± 0.07%), Castanea mollissima Blume shells (27.34% ± 0.01%), and Carya cathayensis Sarg shells (49.78% ± 0.01%), respectively. The pyrolysis processes of three kinds of shells generally included three stages, namely dehydration, pyrolysis, and carbonization. The peak values and the appearance times of their pyrolysis rates were closely related to their compositions.
Infrared-Spectral Characteristics of Camellia oleifera Shell/Meal during Composting  [PDF]
Jinping Zhang, Yue Ying, Xuebin Li, Xiaohua Yao
Agricultural Sciences (AS) , 2018, DOI: 10.4236/as.2018.910090
Abstract: The compost products of Camellia oleifera shell/meal mixed at different mass ratios were characterized by Fourier-transform infrared spectroscopy (FTIR) at different composting stages to monitor the structural changes of their components. The results showed that the amount of Camellia oleifera meal significantly affected the composting rate of the shell, but did not change the degradation order and decomposition of the related compounds. During the composting process, microorganisms used the highly decomposable carbon source materials, such as proteins and sugars, first to grow and multiply, and then decomposed hemicellulose, cellulose and lignin by oxidative cleavage after these nutrients were consumed to a certain extent. The decomposition products were then condensed into more stable humic acids. The degradation rates of the compounds were directly proportional to the amount of Camellia oleifera?meal. The compounds in Camellia oleifera shell were composted faster with higher amounts of Camellia oleifera meals, resulting in less lignocellulose in the final products.
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