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Search Results: 1 - 10 of 716 matches for " Jiannong Cen "
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Neural differentiation of allogenic mixed-cultured rat bone mesenchymal stem cells  [PDF]
Jun Zhou, Huilin Yang, Jiannong Cen
Journal of Biomedical Science and Engineering (JBiSE) , 2013, DOI: 10.4236/jbise.2013.64058
Abstract:

Many studies showed that bone mesenchymal stem cells (BMSCs) can transdifferentiate to neural cell in vitro. The purpose of this study was to investigate the mixed-culture of allogenic rat BMSCs in vitro, and to perform neural differentiation potential characterization. Rat BMSCs were isolated and cultured by plastic adherence and density gradient centrifugation respectively, and the 3rd passage cells were harvested and mixed-cultured with same concentration. The second passage cells of the mixed-cultured cells were obtained to perform Wright-Gemsa staining for morphological observation, to identify the surface marker of CD29, CD45, CD90 by flow cytometry and induced to differentiate into neural cell, then performed immunocytochemistry of Nestin, NSE and GFAP. Results showed that after Wright-Giemsa staining, the mixed-cultured cells displayed typical spindle-shape, presented layered and whirlpool-like growth; and the mixed-cultured cells were positive for CD29 and CD90, but negative for CD45 by flow cytometry. After induction, the mixed-cultured cells appeared morphological changes of neuron and glial cell, and were positive expression of Nestin, neuron specific enolase (NSE) and glial fibrillary acidic protein (GFAP). The results demonstrated that the mixed-cultured allogenic rat BMSCs can be induced into neural cell such as neuron and glial cell in vitro.

Matrix Metalloproteinase-2 and -9 Secreted by Leukemic Cells Increase the Permeability of Blood-Brain Barrier by Disrupting Tight Junction Proteins
Saran Feng, Jiannong Cen, Yihong Huang, Hongjie Shen, Li Yao, Yuanyuan Wang, Zixing Chen
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0020599
Abstract: Central nervous system (CNS) involvement remains an important cause of morbidity and mortality in acute leukemia, the mechanisms of leukemic cell infiltration into the CNS have not yet been elucidated. The blood-brain barrier (BBB) makes CNS become a refugee to leukemic cells and serves as a resource of cells that seed extraneural sites. How can the leukemic cells disrupt this barrier and invasive the CNS, even if many of the currently available chemotherapies can not cross the BBB? Tight junction in endothelial cells occupies a central role in the function of the BBB. Except the well known role of degrading extracellular matrix in metastasis of cancer cells, here we show matrix metalloproteinase (MMP)-2 and -9, secreted by leukemic cells, mediate the BBB opening by disrupting tight junction proteins in the CNS leukemia. We demonstrated that leukemic cells impaired tight junction proteins ZO-1, claudin-5 and occludin resulting in increased permeability of the BBB. However, these alterations reduced when MMP-2 and -9 activities were inhibited by RNA interference strategy or by MMP inhibitor GM6001 in an in vitro BBB model. We also found that the disruption of the BBB in company with the down-regulation of ZO-1, claudin-5 and occludin and the up-regulation of MMP-2 and -9 in mouse brain tissues with leukemic cell infiltration by confocal imaging and the assay of in situ gelatin zymography. Besides, GM6001 protected all mice against CNS leukemia. Our findings suggest that the degradation of tight junction proteins ZO-1, claudin-5 and occludin by MMP-2 and -9 secreted by leukemic cells constitutes an important mechanism in the BBB breakdown which contributes to the invasion of leukemic cells to the CNS in acute leukemia.
Cultivating the College Students’ Creative Thinking in Industrial Design  [PDF]
Hua Cen, Chuandong Ma
Creative Education (CE) , 2013, DOI: 10.4236/ce.2013.48077
Abstract:

This paper probes into the source of “originality” in developing the creative thinking of the science students majoring in industrial design. The authors believe that the critical factors for the source of “originality” lie in not only the internal cause, but also the external cause. Whether the science students take a great consideration of art and humanity courses, in other words, whether they are aware of the relationship between artistical thought and industrial design or not, it is very important. In addition, creative capacity cannot be taught, and it only results from inspiration and guidance of teachers from multidisciplinary.


Public Health Insurance System Reform and Its Impact on Health Service Utilization in Rural China: Evidence from CHNS 2000 and 2011  [PDF]
Xinxin Ma, Yangyang Cen
Chinese Studies (ChnStd) , 2017, DOI: 10.4236/chnstd.2017.62009
Abstract: This study employs an empirical analysis to investigate the impact of the New Cooperative Medical Scheme (NCMS) on health service utilization in Chinese rural region using the 2000 and 2011 China Health and Nutrition Survey (CHNS) longitudinal survey data and Difference in Difference (DID) analysis method. The major conclusions are as follows. First, individual characteristic factors, enabling factors, health care need factors, and lifestyle factors affect health service utilization, which is consistent with Anderson model. Second, when controlled these factors based on Anderson model, the results indicate that the NCMS did not affect health service utilization (outpatient, inpatient, and health care examination) of individual when ill. Third, to consider the disparity of health care demand and supply, we also employ the analysis utilized the subsamples to take robustness checks. The results indicate that there is no difference statistically in health service utilization between the NCMS enrollment group and the non-enrollment group by age groups (16 - 49 aged group and 50 age and over group), income groups (High, Middle and Low-income groups), and regional groups (East, West and Central Regions). Therefore, it can be said that the NCMS did not improve either health service utilization for patients or preventative health care for rural residents in China.
Analysis of Thermo-Magneto-Elastic Nonlinear Dynamic Response of Shallow Conical Shells  [PDF]
Shende Cen, Jiachu Xu
Engineering (ENG) , 2018, DOI: 10.4236/eng.2018.1012058
Abstract: The dynamic response study on thermo-magneto-elastic behavior of shallow conical shell in a time-dependent magnetic field is investigated, and the dynamic responses of displacement of shallow conical shell under mechanical loads, electromagnetic fields and temperature field coupling are analyzed. Based on Maxwell’s equations, heat conduction equation and nonlinear equations of classical plates and shells, the nonlinear dynamic response governing equations are derived. The electromagnetic field and temperature field equations are solved using variable separating technique, the nonlinear elastic field equations are solved by Galerkin method. The variation of temperature, magnetic field intensity and displacement with time under the coupling effect of the applied magnetic field and the surface uniform load were obtained. The influence of frequency of the applied magnetic field on the displacement wave forms is discussed.
An Empirical Analysis of English Learning Process and Impact Factors of Open Distance Education  [PDF]
Hongxia Cen
Open Access Library Journal (OALib Journal) , 2015, DOI: 10.4236/oalib.1101599
Abstract: With the whole process of English learning as a research perspective, the relationship among adult English learners’ social situation, motivation, learning strategies and learning effects based on self-determined motivation theory and language learning strategy theory is explored in the study. The findings are obtained through empirical analysis, and the teaching feedback, through which some suggestions are put forward, including constructing autonomy-supportive social situation in order to improve the effect of distance English teaching, improving learning motivation by solving the practical problem, perfecting the corresponding teaching strategies and realizing the learning effectiveness [1].
An Intrinsic Smoothing Mechanism For Gamma-Ray Burst Spectra in the Fireball Model
Renyue Cen
Physics , 1999, DOI: 10.1086/312034
Abstract: It is shown that differential Doppler shift of different patches of the blastwave front in the fireball model at varying angles to the line of sight could provide an intrinsic smoothing mechanism for the spectra of gamma-ray bursts (GRBs) and the associated afterglows at lower energy bands. For the model parameters of interest, it is illustrated that a monochromatic spectrum at $\nu$ in blastwave comoving frame is smoothed and observed to have a half-width-half-maximum (HWHM) of $\sim (0.6-2.0)\nu$. Some other implications of this smoothing process are discussed. In particular, if the circumburster medium is uniform and electron and magnetic energies are fixed fractions of the total post-shock energy with time, the observed GRB or afterglow spectra cannot be steeper than $\nu^{-\alpha}$ with $\alpha=0.75-1.25$, regardless of the intrinsic spectra in the comoving shock frame; i.e., a very steep electron distribution function (with $p>3$) could produced an observed spectrum with $\alpha\sim 1$. In addition, a generic fast-rise-slow-decay type of GRB temporal profile is expected.
A Possible Lateral Gamma-Ray Burst Jet from Supernova 1987A
Renyue Cen
Physics , 1999, DOI: 10.1086/312286
Abstract: There was a bright, transient companion spot to SN1987A with a projected distance of about 17 light-days, observed by optical speckle interferometry one to two months after explosion. It is shown here that the bright spot may be due to a receding ultra-relativistic jet traveling at 53 degress to the observer-to-SN1987A vector, through a circumstellar medium of density profile rho(r) ~ r^-2. If it had approached us along the line of sight, a very bright gamma-ray burst would have been seen with an apparent isotropic energy of about 10^54 erg and an openning angle of a few degrees. The model provides an adequate explanation for the evolution of the spot, although there are still problems in explaining its observed color. This model implies that at least some GRBs would be seen as going through a medium with density rho(r) ~ r^-2 rather than a uniform medium, which is frequently adopted in GRB calculations. Improved analysis of the speckle data has revealed another and fainter spot on the opposite side.
Internal Velocity and Mass Distributions in Clusters of Galaxies for a Variety of Cosmogonic Models
Renyue Cen
Physics , 1994, DOI: 10.1086/174971
Abstract: The mass and velocity distributions in the outskirts ($0.5-3.0h^{-1}$Mpc) of clusters of galaxies are examined for a suite of cosmogonic models utilizing large-scale Particle-Mesh (PM) simulations ($500^3$ cells, $250^3$ particles and box size of $100h^{-1}$Mpc, giving a nominal resolution of $0.2h^{-1}$Mpc with the true resolution about $0.5h^{-1}$Mpc). Through a series of model computations, designed to isolate the different effects, we find that both $\Omega_0$ and $P_k$ ($\lambda\le 16h^{-1}$Mpc) are important to the mass and velocity distributions in clusters of galaxies. More details in the full abstract.
Towards Understanding Galaxy Clusters and Their Constituents:Projection Effects on Velocity Dispersion, X-Ray Emission, Mass Estimates, Gas Fraction and Substructure
Renyue Cen
Physics , 1996, DOI: 10.1086/304394
Abstract: We study the projection effects on various observables of clusters of galaxies at redshift near zero, including cluster richness, velocity dispersion, X-ray luminosity, three total mass estimates (velocity-based, temperature-based and gravitational lensing derived), gas fraction and substructure. Unlike previous studies focusing on the Abell clusters, we conservatively assume that both optical and X-ray observations can determine the source (galaxy or hot X-ray gas) positions along the line of sight as well as in the sky plane accurately; hence we only include sources inside the velocity space defined by the cluster galaxies (filtered through the pessimistic 3 sigma clipping algorithm) as possible contamination sources. Projection effects are found to be important for some quantities but insignificant for others. We show that, on average, the gas to total mass ratio in clusters appears to be 30-40% higher than its corresponding global ratio. Independent of its mean value, the broadness of the observed distribution of gas to total mass ratio is adequately accounted for by projection effects, alleviating the need to invoke (though not preventing) other non gravitational physical processes. While the moderate boost in the ratio narrows the gap, it is still not quite sufficient to reconcile the standard nucleosynthesis value of $\Omega_b=0.0125(H_0/100)^{-2}$ and $\Omega=1$ with the observed gas to mass ratio value in clusters of galaxies, $0.05(H_0/100)^{-3/2}$, for any plausible value of $H_0$. However, it is worth noting that real observations of X-ray clusters, especially X-ray imaging observations, may be subject to more projection contaminations than we allow for in our analysis. In contrast, the X-ray luminosity of a cluster within a radius $\leq 1.0h^{-1}$Mpc is hardly
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