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Search Results: 1 - 10 of 34414 matches for " Guohong Zhou "
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MEDIAN SUCCESSFUL SACCADE SIZE AND VISUAL LOBE
二维视觉搜索中成功扫视幅度中值与视力角

ZHOU Guohong,
周果宏

自动化学报 , 1999,
Abstract: The paper studies visual lobe by measuring and calculating median successful saccade size(MSSS) in 2 D visual search.The experiment results show that MSSS is a function of Michaelson contrast and the clutter density.During scanning a search scene,saccade eye movement is directed by a combination of global covering plan and moment to moment adjustments guided by useful peripheral information.At last,a Gaussian model is given to fit the experiment data.This model captures not only the first order effects of clutter and contrast but also their reciprocal interactions.
Human Health Risk Assessment of Trihalomethanes through Ingestion of Drinking Water in Shenzhen, China  [PDF]
Daokui Fang, Guohong Zhou, Shuyuan Yu, Jinshu Feng, Yinsheng Guo
Open Access Library Journal (OALib Journal) , 2019, DOI: 10.4236/oalib.1105406
Abstract:
The potential health hazards of trihalomethanes (THMs) contamination in drinking water in Shenzhen were estimated. The concentrations of THMs in drinking water from 13 centralized water supply systems were determined from Jan 2015 to Dec 2016 in Shenzhen. The water environmental health risk assessment model recommended by USEPA was established based on the water monitoring data of THMs. Preliminary health risks of THMs through ingestion of drinking water were assessed. The median concentrations of THMs, TCM, DBCM, BDCM and TBM in drinking water were 37.0, 24.5, 2.3, 7.8 and 0.3 μg/L respectively. The values of carcinogenic risks for THMs, TCM, DBCM, BDCM, and TBM to the individual per year in drinking water were 4.52 × 10-5, 2.38 × 10-5, 6.07 × 10-6, 1.52 × 10-5 and 7.45 × 10-8 respectively. The values of non-carcinogenic risks for THMs, TCM, DBCM, BDCM and TBM to the individual per year in drinking water were 9.32 × 10-2, 7.68 × 10-2, 3.61 × 10-3, and 1.23 × 10-2 and 4.71 × 10-4 respectively. The health risk caused by THMs to the individual through ingestion of drinking water was in the order of TCM, BDCM, DBCM and TBM from high to low. The carcinogenic risks induced by THMs through ingestion of drinking water are acceptable with tolerable value offered by USEPA (1.0 × 10-6 - 1.0 × 10-4), but reached to the tolerable value (5.0 × 10-5) by International Commission on Radiological Protection (ICRP). The non-carcinogenic risk of THMs is tolerable (HI < 1).


Molecular cloning of a fulllength cDNA for ECBP21 from Angelica dahurica
Guohong Mao,Wenqiang Tang,Yi Guo,Cunbao Ding,Rengang Zhou,Daye Sun
Chinese Science Bulletin , 2002, DOI: 10.1360/02tb9247
Abstract: ECBP21 is an extracellular calmodulin-binding protein which was first detected and purified from extracellular extracts of suspension-cultured cells of Angelica dahurica. The purified protein was electroblotted onto PVDF membrane and the amino acid sequences from 1 to 20 were determined. Using degenerate oligonucleotides of the sequence, a full-length cDNA coding for ECBP21 was isolated by a combination of RT-PCR and 5′-RACE cloning. The cDNA contains 947 nucleotides and codes for a precursor protein of 216 amino acids. The N-terminal 1–25 amino acid sequence is a predicted signal peptide and the other 26–216 amino acid sequence is a mature peptide. The 26–45 amino acid sequence shows identity with the N-terminal amino acid sequence of purified ECBP21 from Angelica dahurica. The fragment of encoding the mature protein was cloned into pET-28b(+) and transformed into E. coli BL21(DE3). A protein with relative molecular mass 21 ku was expressed in E. coli. Using a biotinylated-CaM gel overlay technique, the expression protein was tested for its ability to bind CaM. The results indicated that the expression protein is a Ca2+-dependent CaM-binding protein. Thus, these results further defined the cDNA clone for ECBP21. This work laid a foundation for elucidating biological functions of ECBP21 by using molecular biological means.
Effect of human activities on soil environment and plant species diversity of elm sparse woods
人类活动对榆树疏林土壤环境和植物多样性的影响

YANG Li min,ZHOU Guangsheng,WANG Guohong,WANG Yuhui,
杨利民
,周广胜

应用生态学报 , 2003,
Abstract: Human activities have a major impact on the biodiversity of the earth, while biodiversity change is considered as an important global change in its own right. Elm sparse woods is a climax community distributed on the sandland in temperate steppe zone. Its habitat conditions are much more fragile, and are easily destroyed. Our studies on the effect of human activities on soil environment and plant diversity showed that the main soil environmental factors and plant species diversity had some obvious changes, of which, the changes of man made pine woods and heavy grazing disturbance were the largest, and the of man made poplar woods were the in those next place. It is suggested that natural laws and consistency of ecosystem processes in the low and long temporal scale should be considered adequately in the environment management of sandland.
Hydrodynamic and N-body Schemes On An Unstructured, Adaptive Mesh with Applications to Cosmological Simulations
Guohong Xu
Physics , 1996, DOI: 10.1093/mnras/288.4.903
Abstract: The theory and application of numerical methods for unstructured meshes have been improved significantly in recent years. Because the grids can be place arbitrarily in space, unstructured meshes can provide much higher spatial resolution than regular meshes. The built-in nature of mesh adaptivity for unstructured meshes gives one way to simulate highly dynamic, hierarchical problems involving both collisionless dark matter and collisional gas dynamics. In this paper, we describe algorithms to construct unstructured meshes from a set of points with periodic boundary conditions through Delaunay triangulation, and algorithms to solve hydrodynamic and N-body problems on an unstructured mesh . A combination of a local transformation algorithm and the traditional Bowyer-Watson algorithm gives an efficient approach to perform Delaunay triangulation. A novel algorithm to solve N-body equations of motion on an unstructured mesh is described. Poisson's equation is solved using the conjugate gradient method. A gas-kinetic scheme based on the BGK model to solve Euler equations is used to evolve the hydrodynamic equations. We apply these algorithms to solve cosmological settings, which involve both dark and baryonic matter. Various cooling and heating processes for primordial baryonic matter are included in the code. The numerical results show that the N-body and hydrodynamic algorithms based on unstructured meshes with mesh refinement are well-suited for hierarchical structure formation problems.
A New Parallel N-body Gravity Solver: TPM
Guohong Xu
Physics , 1994, DOI: 10.1086/192166
Abstract: We have developed a gravity solver based on combining the well developed Particle-Mesh (PM) method and TREE methods. It is designed for and has been implemented on parallel computer architectures. The new code can deal with tens of millions of particles on current computers, with the calculation done on a parallel supercomputer or a group of workstations. Typically, the spatial resolution is enhanced by more than a factor of 20 over the pure PM code with mass resolution retained at nearly the PM level. This code runs much faster than a pure TREE code with the same number of particles and maintains almost the same resolution in high density regions. Multiple time step integration has also been implemented with the code, with second order time accuracy. The performance of the code has been checked in several kinds of parallel computer configuration, including IBM SP1, SGI Challenge and a group of workstations, with the speedup of the parallel code on a 32 processor IBM SP2 supercomputer nearly linear (efficiency $\approx 80\%$) in the number of processors. The computation/communication ratio is also very high ($\sim 50$), which means the code spends $95\%$ of its CPU time in computation.
Positive Solutions for a General Gause-Type Predator-Prey Model with Monotonic Functional Response
Guohong Zhang,Xiaoli Wang
Abstract and Applied Analysis , 2011, DOI: 10.1155/2011/547060
Abstract: We study a general Gause-type predator-prey model withmonotonic functional response under Dirichlet boundary condition. Necessary andsufficient conditions for the existence and nonexistence of positive solutions for thissystem are obtained by means of the fixed point index theory. In addition, the localand global bifurcations from a semitrivial state are also investigated on the basis ofbifurcation theory. The results indicate diffusion, and functional response does helpto create stationary pattern.
Approximation of Solutions of an Equilibrium Problem in a Banach Space
Hecai Yuan,Guohong Shi
Journal of Applied Mathematics , 2012, DOI: 10.1155/2012/812783
Abstract: An equilibrium problem is investigated based on a hybrid projection iterative algorithm. Strong convergence theorems for solutions of the equilibrium problem are established in a strictly convex and uniformly smooth Banach space which also enjoys the Kadec-Klee property.
Novel Multiple Markers to Distinguish Melanoma from Dysplastic Nevi
Guohong Zhang, Gang Li
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0045037
Abstract: Background Distinguishing melanoma from dysplastic nevi can be challenging. Objective To assess which putative molecular biomarkers can be optimally combined to aid in the clinical diagnosis of melanoma from dysplastic nevi. Methods Immunohistochemical expressions of 12 promising biomarkers (pAkt, Bim, BRG1, BRMS1, CTHRC1, Cul1, ING4, MCL1, NQO1, SKP2, SNF5 and SOX4) were studied in 122 melanomas and 33 dysplastic nevi on tissue microarrays. The expression difference between melanoma and dysplastic nevi was performed by univariate and multiple logistic regression analysis, diagnostic accuracy of single marker and optimal combinations were performed by receiver operating characteristic (ROC) curve and artificial neural network (ANN) analysis. Classification and regression tree (CART) was used to examine markers simultaneous optimizing the accuracy of melanoma. Ten-fold cross-validation was analyzed for estimating generalization error for classification. Results Four (Bim, BRG1, Cul1 and ING4) of 12 markers were significantly differentially expressed in melanoma compared with dysplastic nevi by both univariate and multiple logistic regression analysis (p < 0.01). These four combined markers achieved 94.3% sensitivity, 81.8% specificity and attained 84.3% area under the ROC curve (AUC) and the ANN classified accuracy with training of 83.2% and testing of 81.2% for distinguishing melanoma from dysplastic nevi. The classification trees identified ING4, Cul1 and BRG1 were the most important classification parameters in ranking top-performing biomarkers with cross-validation error of 0.03. Conclusions The multiple biomarkers ING4, Cul1, BRG1 and Bim described here can aid in the discrimination of melanoma from dysplastic nevi and provide a new insight to help clinicians recognize melanoma.
Conserved Orb6 Phosphorylation Sites Are Essential for Polarized Cell Growth in Schizosaccharomyces pombe
Guohong Liu, Dallan Young
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0037221
Abstract: The Ndr-related Orb6 kinase is a key regulator of polarized cell growth in fission yeast, however the mechanism of Orb6 activation is unclear. Activation of other Ndr kinases involves both autophosphorylation and phosphorylation by an upstream kinase. Previous reports suggest that the Nak1 kinase functions upstream from Orb6. Supporting this model, we show that HA-Orb6 overexpression partially restored cell polarity in nak1 ts cells. We also demonstrated by coimmunoprecipitation and in vitro binding assays that Nak1 and Orb6 physically interact, and that the Nak1 C-terminal region is required forNak1/Orb6 complex formation in vivo. However, results from in vitro kinase assays did not show phosphorylation of recombinant Orb6 by HA-Nak1, suggesting that Orb6 activation may not involve direct phosphorylation by Nak1. To investigate the role of Orb6 phosphorylation and activity, we substituted Ala at the ATP-binding and conserved phosphorylation sites. Overexpression of kinase-dead HA-Orb6K122A in wild-type cells resulted in a loss of cell polarity, suggesting that it has a dominant-negative effect, and it failed to rescue the polarity defect of nak1 or orb6 ts mutants. Recombinant GST-Orb6S291A did not autophosphorylate in vitro suggesting that Ser291 is the primary autophosphorylation site. HA-Orb6S291A overexpression only partially rescued the orb6 polarity defect and failed to rescue the nak1 defect, suggesting that autophosphorylation is important for Orb6 function. GST-Orb6T456A autophosphorylated in vitro, indicating that the conserved phosphorylation site at Thr456 is not essential for kinase activity. However, HA-Orb6T456A overexpression had similar effects as overexpressing kinase-dead HA-Orb6K122A, suggesting that Thr456 is essential for Orb6 function in vivo. Also, we found that both phosphorylation site mutations impaired the ability of Myc-Nak1 to coimmunoprecipitate with HA-Orb6. Together, our results suggest a model whereby autophosphorylation of Ser291 and phosphorylation of Thr456 by an upstream kinase promote Nak1/Orb6 complex formation and Orb6 activation.
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