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Search Results: 1 - 10 of 104556 matches for " Bi Cheng Liu "
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Biomass partitioning and water content relationships at the branch and whole-plant levels and as a function of plant size in Elaeagnus mollis populations in Shanxi, North China

Ren-Tao Liu,Run-Cheng Bi,Ha-Lin Zhao,

生态学报 , 2009,
Abstract: Understanding of the biomass (dry weight) allocation and water relations in populations will provide useful information on the growth patterns and resource-allocation dynamics. By destructive sampling, foliage, branch and root biomass were measured in the endangered shrub Elaeagnus mollis populations growing in Shanxi province, North China. Biomass partitioning and water content relationships were compared at the branch and whole-plant levels, and as a function of basal diameter (plant size). The biomass was mainly distributed in the bigger branches at the branch level, and in the branch wood at the whole-plant level, and branch biomass (but not foliage or root biomass) increases significantly with increasing basal diameter. As a result, branch wood became the major biomass pool, even though considerable biomass was also allocated to the roots. However, the relative water content decreased from the periphery of the crown to the interior of the shrub at the branch level, and from the aboveground to the belowground at the whole-plant level though no significant variation among foliage, branches, and roots. Yet it increased significantly for the whole-plant with increasing basal diameter. The ratio of belowground to aboveground biomass was smaller than 1.0, even as a function of basal diameter. These growth responses indicated a strong adaptation to the shrub’s growing conditions. Biomass was primarily allocated above the ground and the aboveground components grew faster than the belowground one.
The research of testing method for timing precision of seismic data acquisition systems

LIU Yi-Cheng,YI Bi-Jin,GONG Qi-Gang,

地球物理学进展 , 2009,
Abstract: The timing precision of telemetry seismic data acquisition systems is a very important performance index, which pases effects on stratum resolution of seismic prospecting directly. The timing precision of telemetry seismic data acquisition systems depends on the precision of sampling rates of data acquisition units. This paper gives the basic definition of timing precision first, based on analog-digital signal processing technique. It studies the single squire wave and double unit impulse methods of testing timing precision and compares their testing precisions,and presents test results using the method mentioned. At last it discusses test errors.
Role of EZH2 in the Growth of Prostate Cancer Stem Cells Isolated from LNCaP Cells
Kuiqing Li,Cheng Liu,Bangfen Zhou,Liangkuan Bi,Hai Huang,Tianxin Lin,Kewei Xu
International Journal of Molecular Sciences , 2013, DOI: 10.3390/ijms140611981
Abstract: Enhancer of zeste homolog 2 (EZH2) plays a crucial role in embryonic and somatic stem cells for their proliferation and differentiation. However, the roles and underlying mechanisms of EZH2 in prostate cancer stem cells (PCSCs) remain unknown. This study aimed to investigate the effects of EZH2 on PCSCs. PCSCs were isolated from the human prostate cancer cell line LNcap by fluorescence activated cell sorting (FACS). EZH2 expression was compared between PCSCs and non-PCSCs. The association between EZH2 function and PCSC growth was investigated using siRNA-mediated knock-down of EZH2. Cell growth was investigated by MTT, cell cycle and apoptosis of PCSCs were explored by flow cytometric analysis. Finally, the upstream pathway miRNA level was determined via a luciferase reporter assay, and the downstream pathway cycle regulators were examined via reverse transcriptase-polymerase chain reaction. The results showed that LNcap cell line comprised a greater proportion of CD44 +/CD133 + cells by comparison to the PC-3 cell line. EZH2 was up-regulated in PCSCs compared with non-PCSCs. Silence of EZH2 inhibited cell growth and the cell cycle and promoted the progression of apoptosis. Furthermore, EZH2 was a direct target of miR-101 in PCSCs and EZH2’s mRNA levels were inversely correlated with miR-101 expression and cyclin E2 (a cell-cycle regulator) was suppressed by siEZH2. In conclusion, EZH2 is essential for PCSC growth, partly through a negative regulation by miR-101 and positively regulating cyclin E2.
Structural View of a Non Pfam Singleton and Crystal Packing Analysis
Chongyun Cheng, Neil Shaw, Xuejun Zhang, Min Zhang, Wei Ding, Bi-Cheng Wang, Zhi-Jie Liu
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0031673
Abstract: Background Comparative genomic analysis has revealed that in each genome a large number of open reading frames have no homologues in other species. Such singleton genes have attracted the attention of biochemists and structural biologists as a potential untapped source of new folds. Cthe_2751 is a 15.8 kDa singleton from an anaerobic, hyperthermophile Clostridium thermocellum. To gain insights into the architecture of the protein and obtain clues about its function, we decided to solve the structure of Cthe_2751. Results The protein crystallized in 4 different space groups that diffracted X-rays to 2.37 ? (P3121), 2.17 ? (P212121), 3.01 ? (P4122), and 2.03 ? (C2221) resolution, respectively. Crystal packing analysis revealed that the 3-D packing of Cthe_2751 dimers in P4122 and C2221 is similar with only a rotational difference of 2.69° around the C axes. A new method developed to quantify the differences in packing of dimers in crystals from different space groups corroborated the findings of crystal packing analysis. Cthe_2751 is an all α-helical protein with a central hydrophobic core providing thermal stability via π:cation and π: π interactions. A ProFunc analysis retrieved a very low match with a splicing endonuclease, suggesting a role for the protein in the processing of nucleic acids. Conclusions Non-Pfam singleton Cthe_2751 folds into a known all α-helical fold. The structure has increased sequence coverage of non-Pfam proteins such that more protein sequences can be amenable to modelling. Our work on crystal packing analysis provides a new method to analyze dimers of the protein crystallized in different space groups. The utility of such an analysis can be expanded to oligomeric structures of other proteins, especially receptors and signaling molecules, many of which are known to function as oligomers.
An Efficient Tool for the Construction of Multiple-cistronic Vectors: FMDV 2A
构建多顺反子表达载体的有效工具——FMDV 2A

LIU Bi-Sheng,LIU Xin-Yuan,QIAN Cheng,

生物工程学报 , 2007,
Abstract: Recently,cancer therapy with mutiple genes has been attached with great attention.However,at present there is no efficient tool to construct multiple-cistrons.The large sizes and the imbalance in expression of most traditional tools,such as ribosome entry sites(IRESes),greatly block their wide employment in the construction of multiple cistronic gene therapy vectors.The self-cleaving peptide 2A from foot-and-mouth disease virus(FMDV)has a very small size,and more importantly,high cleavage activity in artifical bicistron,which bring new hope for mutiple genes therapy stategy.In this article,the characteristics and cleavage activities of FMDV 2A will be elucidated,and we further outline its applications in cancer gene therapy.
Motor Cortex-Periaqueductal Gray-Spinal Cord Neuronal Circuitry May Involve in Modulation of Nociception: A Virally Mediated Transsynaptic Tracing Study in Spinally Transected Transgenic Mouse Model
Da-Wei Ye, Cheng Liu, Tao-Tao Liu, Xue-Bi Tian, Hong-Bing Xiang
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0089486
Abstract: Several studies have shown that motor cortex stimulation provided pain relief by motor cortex plasticity and activating descending inhibitory pain control systems. Recent evidence indicated that the melanocortin-4 receptor (MC4R) in the periaqueductal gray played an important role in neuropathic pain. This study was designed to assess whether MC4R signaling existed in motor cortex- periaqueductal gray- spinal cord neuronal circuitry modulated the activity of sympathetic pathway by a virally mediated transsynaptic tracing study. Pseudorabies virus (PRV)-614 was injected into the left gastrocnemius muscle in adult male MC4R-green fluorescent protein (GFP) transgenic mice (n = 15). After a survival time of 4–6 days, the mice (n = 5) were randomly assigned to humanely sacrifice, and spinal cords and brains were removed and sectioned, and processed for PRV-614 visualization. Neurons involved in the efferent control of the left gastrocnemius muscle were identified following visualization of PRV-614 retrograde tracing. The neurochemical phenotype of MC4R-GFP-positive neurons was identified using fluorescence immunocytochemical labeling. PRV-614/MC4R-GFP dual labeled neurons were detected in spinal IML, periaqueductal gray and motor cortex. Our findings support the hypothesis that MC4R signaling in motor cortex-periaqueductal gray-spinal cord neural pathway may participate in the modulation of the melanocortin-sympathetic signaling and contribute to the descending modulation of nociceptive transmission, suggesting that MC4R signaling in motor cortex- periaqueductal gray-spinal cord neural pathway may modulate the activity of sympathetic outflow sensitive to nociceptive signals.
Construction of Antibody Microarray Based On Sandwich Immunoassay

Bi-Cheng Liu,Zu-Hong Lu,

中国生物工程杂志 , 2008,
Abstract: Objective: To establish a method of constructing antibody microarray based on sandwich immunoassay. Methods: Modified glass slides were robotically printed with capture antibodies against MCP-1, then dilutions of the cytokine were applied to the arrays and the protein was detected with biotin-labeled antibody coupled with Cy3- conjugated streptavidin. A laser confocal scanner was used to obtain the images and the signal intensity was analyzed subsequently. Various factors in the production of antibody microarrays were analyzed: the capture antibody concentrations, blocking buffers, reproducibility and quantitative ability of the system, two-cytokine analysis and shelf life of the post-printing slides. Results: The signal intensities increased with increasing capture antibody concentration; 2%BSA and 5% casein were proper as the blocking buffer for this system; The results revealed high reproducibility with regard to intra-array (1.3%) and the inter-array (8.7%) variation at the capture antibody concentration of 125ug/ml and good qualitative ability with a correlation coefficient of 0.9995 between the antigen concentration and the signal intensity; Besides, an antibody microarray for the parallel analysis of two cytokines was established and the printed arrays could be stored for at least two months without any apparent change of the performance parameters. Conclusion: A method for constructing antibody microarray based on sandwich immunoassay was established which might lay a foundation for fabrication of antibody microarray with multiplexing and quantitative capacity.
Adaptive Video Coding Based on Bayes-Cost Function

LIU Bao fang,PING Xi jian,LI Bi cheng,SHAO Mei zhen,

中国图象图形学报 , 2001,
Abstract: 针对图象质量和传输码率在不同的视频传输系统中的不同要求,给出了一种用于视频编码宏块分类的贝叶斯代价函数,并依此构成了基于贝叶斯决策的自适应编码算法。试验表明,该算法可以实现图象质量和传输码率的主观折衷,并能提高重建图象的质量和平均峰值信噪比。
Named entity relation extraction based on SVM training by positive and negative cases

LIU Lu,LI Bi-cheng,ZHANG Xian-fei,

计算机应用 , 2008,
Abstract: Based on the characteristics of the Chinese named entity relation extraction, features were selected and feature vectors were constructed in terms of Chinese morphological, grammar and semantics. Then potential named entity pairs in accordance with the specific entity relation template were extracted and divided into positive and negative cases. Support Vector Machine (SVM) classifier was trained by the positive and negative cases and used to judge the relation of the potential named entity pairs. Experimental results prove that this new method can effectively improve the accuracy of Chinese named entity relation extraction.
Effects of Heterogeneous Competitor Distribution and Ramet Aggregation on the Growth and Size Structure of a Clonal Plant
Bi-Cheng Dong, Jiu-Zhong Wang, Rui-Hua Liu, Ming-Xiang Zhang, Fei-Hai Yu
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0068557
Abstract: Spatially heterogeneous distribution of interspecific competitors and intraspecific aggregation of offspring ramets may affect the growth and size structure of clonal plant populations, but these have been rarely studied. We conducted a greenhouse experiment in which we grew a population of eight offspring ramets (plants) of the stoloniferous clonal plant Hydrocotyle vulgaris aggregately or segregately in two homogeneous treatments with or without a competing grass Festuca elata and a heterogeneous treatment with a patchy distribution of the grass. In patchy grass treatments, H. vulgaris produced markedly more biomass, ramets and stolons in open patches (without grasses) than in grass patches, but displayed lower size variations as measured by coefficient of variation of biomass, ramets and stolons among the eight plants. In open areas, H. vulgaris produced statistically the same amounts of biomass and even more stolons and showed higher size variations in patchy grass treatments than in open (no grass) treatments. In grass areas, H. vulgaris grew much worse and displayed higher size variations in patchy grass treatments than in full grass treatments. Ramet aggregation decreased the growth of H. vulgaris in open treatments and in both open and grass patches in patchy grass treatments, but had little effect in full grass treatments. Ramet aggregation had little effect on size variations. Therefore, heterogeneous distribution of competitors can affect the growth and size structure of clonal plant populations, and ramet aggregation may decrease population growth when they grow in open environments or heterogeneous environments with a patchy distribution of interspecific competitors.
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