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403 results on '"Zhang, Leying"'

140. Metronomic Doses of Temozolomide Enhance the Efficacy of Carbon Nanotube CpG Immunotherapy in an Invasive Glioma Model

Author

Ouyang, Mao, primary, White, Ethan E., additional, Ren, Hui, additional, Guo, Qin, additional, Zhang, Ian, additional, Gao, Hang, additional, Yanyan, Song, additional, Chen, Xuebo, additional, Weng, Yiming, additional, Da Fonseca, Anna, additional, Shah, Sunny, additional, Manuel, Edwin R., additional, Zhang, Leying, additional, Vonderfecht, Steven L., additional, Alizadeh, Darya, additional, Berlin, Jacob M., additional, and Badie, Behnam, additional

Published
2016
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143. Induction of anti-glioma NK cell response following multiple low-dose intracerebral CpG therapy

Author

Alizadeh, Darya, Zhang, Leying, Brown, Christine E., Farrukh, Omar, Jensen, Michael C., and Badie, Behnam

Subjects
Killer Cells, Natural, Mice, Inbred C57BL, Mice, Adjuvants, Immunologic, Oligodeoxyribonucleotides, Brain Neoplasms, Toll-Like Receptor 9, Animals, Glioma, CD8-Positive T-Lymphocytes, Lymphocyte Activation, T-Lymphocytes, Regulatory, Article
Abstract

Stimulation of toll-like receptor-9 by CpG oligodeoxynucleotides (CpG-ODN) has been shown to counteract the immunosuppressive microenvironment and to inhibit tumor growth in glioma models. These studies, however, have used high doses of CpG-ODN, which can induce toxicity in a clinical setting. The goal of this study was to evaluate the antitumor efficacy of multiple low-dose intratumoral CpG-ODN in a glioma model.Mice bearing 4-day-old intracranial GL261 gliomas received a single or multiple (two or four) intratumoral injections of CpG-ODN (3 microg) every 4 days. Tumor growth was measured by bioluminescent imaging, brain histology, and animal survival. Flow cytometry and cytotoxicity assays were used to assess anti-glioma immune response.Two and four intracranial injections of low-dose CpG-ODN, but not a single injection, eradicated gliomas in 70% of mice. Moreover, surviving animals exhibited durable tumor-free remission (3 months) and were protected from intracranial rechallenge with GL261 gliomas, showing the capacity for long-term antitumor immunity. Although most inflammatory cells seemed to increase, activated natural killer (NK) cells (i.e., NK(+)CD107a(+)) were more frequent than CD8(+)CD107a(+) in the brains of rechallenged CpG-ODN-treated animals and showed a stronger in vitro cytotoxicity against GL261 target cells. Leukocyte depletion studies confirmed that NK cells played an important role in the initial CpG-ODN antitumor response, but both CD8 and NK cells were equally important in long-term immunity against gliomas.These findings suggest that multiple low-dose intratumoral injections of CpG-ODN can eradicate intracranial gliomas possibly through mechanisms involving NK-mediated effector function.

Published
2010

144. RAGE Expression in Tumor-Associated Macrophages Promotes Angiogenesis in Glioma

Author

Chen, Xuebo, primary, Zhang, Leying, additional, Zhang, Ian Y., additional, Liang, Junling, additional, Wang, Huaqing, additional, Ouyang, Mao, additional, Wu, Shihua, additional, da Fonseca, Anna Carolina Carvalho, additional, Weng, Lihong, additional, Yamamoto, Yasuhiko, additional, Yamamoto, Hiroshi, additional, Natarajan, Rama, additional, and Badie, Behnam, additional

Published
2014
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145. 3D Numerical Modeling of Hydrodynamic Flow, Sediment Deposition and Transport in Stormwater Ponds and Alluvial Channels

Author

Zhang, Leying

Subjects
Physics::Fluid Dynamics, Physics::Geophysics
Abstract

Prediction of flow and sediment transport is an important and challenging problem for stormwater management and river engineering applications. This thesis concerns primarily the computation of flow, sediment deposition and transport processes in stormwater ponds and alluvial channels based on a multiphase flow approach in modeling sediment transport. Starting from an existing hydrodynamic Reynolds Averaged Navier-Stokes flow solver, numerical models are developed to predict flow, sediment deposition and transport under the FLUENT software package. Two types of sediment transport models are formulated to consider quantities of present sediment phase volume fractions: a Discrete Phase Model in a Lagrangian frame where the sediment phase occupies a low volume fraction and particle-particle interactions are neglected; a Eulerian two-phase model where each phase is considered as an interpenetrating continuum and particle-particle interactions are not neglegible. The model is capable to model sediment transport with high volume fractions. The solution methodologies are implemented numerically for different case studies. The Discrete Phase Model approach, together with a standard k – ϵ turbulence model, is applied to stormwater pond modeling studies. The use of computational fluid dynamics to simulate flow fields and sediment depositions in stormwater tanks is beneficial because one may compare different factors that affect sedimentation efficiency. In particular, two case studies with different inlet and outlet pipes arrangements are investigated under different steady inflow conditions and bed boundary conditions. A method is employed and hooked to FLUENT for accurate simulations of particle settling behavior in stormwater ponds. The method considers critical bed shear stress as a threshold and evaluates local bed shear stress with this value to determine the particle deposition behavior. It is demonstrated that this model is an efficient 3D hydrodynamic flow and sediment transport numeric model for low sediment-laden flows, thus providing engineers and scientists with a useful tool for studying sediment deposition with a variety of sediment sizes, inflow conditions, and geometry arrangements. In order to gain more insight into the fundamental flow and sediment interaction mechanics of sediment transport, an Eulerian two-phase model embeded in FLUENT is implemented in an open channel with loose bed based on two-phase mass and momentum equations. These equations are used in conjunction with the constitutive relations that are obtained by applying kinetic theory. Different from traditional sediment transport models, this model uses the two-phase theory, and thus, has no need to invoke any empirical sediment transport formulas. In this application, predictions for turbulent fluctuations for the fluid phase are obtained using a modified k – ϵ turbulence model with a supplement of extra terms which take into account the interphase turbulent momentum transfer. Predictions for turbulent quantities for the solid phase are obtained using Tchen-theory correlations for the discrete particles under homogeneous and steady turbulent flows. Besides simulation of sediment transport, the model also provides some ideas for simulating scour and bed deformation. The results presented in this study demonstrate that the model is efficient and quite accurate in dealing with sediment transport and scour simulation with loose bed.

Published
2009
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