目的:提取纯化出辣木叶多糖,初步研究其体外抗炎活性.方法:采用水提醇沉法提取粗多糖,利用Sevag法除去粗多糖中的蛋白,进一步采用DEAE-Sepharose Fast Flow柱层析法、透析法分离纯化得到辣木叶多糖组分MLP100-3;利用傅里叶红外光谱法、...目的:提取纯化出辣木叶多糖,初步研究其体外抗炎活性.方法:采用水提醇沉法提取粗多糖,利用Sevag法除去粗多糖中的蛋白,进一步采用DEAE-Sepharose Fast Flow柱层析法、透析法分离纯化得到辣木叶多糖组分MLP100-3;利用傅里叶红外光谱法、核磁共振光谱法和气相色谱-质谱法对MLP100-3的初级结构及单糖组成进行鉴定与分析.应用Griess试剂法和ELISA酶联免疫吸附测定法分别测定MLP100-3对细胞上清中NO和炎症细胞因子白细胞介素-6(IL-6)、白细胞介素-1β(IL-1β)和肿瘤坏死因子-α(TNF-α)分泌量的影响,并应用逆转录-聚合酶链式反应(RT-PCR)检测MLP100-3对诱导型一氧化氮合酶(iNOS)和TNF-α基因表达水平的影响.结果:辣木叶多糖MLP100-3对炎症细胞NO和TNF-α的产生均有显著的抑制作用,且MLP100-3对炎症细胞产生的iNOS mRNA、环氧合酶-2(COX-2) mRNA和TNF-α mRNA也均有不同程度的抑制作用.结论:MLP100-3具有显著的抗炎活性,推测其可能通过抑制iNOS mRNA和TNF-α mRNA的表达从而抑制核转录因子-κB(NF-κB)信号传导通路激活,影响促炎细胞因子与炎性介质的释放,从而发挥抗炎作用.展开更多
A kind of the general finite difference schemes with intrinsic parallelism for the boundary value problem of the quasilinear parabolic system is studied without assuming heuristically that the original boundary value ...A kind of the general finite difference schemes with intrinsic parallelism for the boundary value problem of the quasilinear parabolic system is studied without assuming heuristically that the original boundary value problem has the unique smooth vector solution. By the method of a priori estimation of the discrete solutions of the nonlinear difference systems, and the interpolation formulas of the various norms of the discrete functions and the fixed-point technique in finite dimensional Euclidean space, the existence and uniqueness of the discrete vector solutions of the nonlinear difference system with intrinsic parallelism are proved. Moreover the unconditional stability of the general finite difference schemes with intrinsic parallelism is justified in the sense of the continuous dependence of the discrete vector solution of the difference schemes on the discrete data of the original problems in the discrete W 2 (2,1) norms. Finally the convergence of the discrete vector solutions of the certain difference schemes with intrinsic parallelism to the unique generalized solution of the original quasilinear parabolic problem is proved.展开更多
A new Lagrangian cell-centered scheme for two-dimensional compressible flows in planar geometry is proposed by Maire et al.The main new feature of the algorithm is that the vertex velocities and the numerical fluxes t...A new Lagrangian cell-centered scheme for two-dimensional compressible flows in planar geometry is proposed by Maire et al.The main new feature of the algorithm is that the vertex velocities and the numerical fluxes through the cell interfaces are all evaluated in a coherent manner contrary to standard approaches.In this paper the method introduced by Maire et al.is extended for the equations of Lagrangian gas dynamics in cylindrical symmetry.Two different schemes are proposed,whose difference is that one uses volume weighting and the other area weighting in the discretization of the momentum equation.In the both schemes the conservation of total energy is ensured,and the nodal solver is adopted which has the same formulation as that in Cartesian coordinates.The volume weighting scheme preserves the momentum conservation and the area-weighting scheme preserves spherical symmetry.The numerical examples demonstrate our theoretical considerations and the robustness of the new method.展开更多
In the construction of nine point scheme, both vertex unknowns and cell-centered unknowns are introduced, and the vertex unknowns are usually eliminated by using the interpolation of neighboring cell-centered unknowns...In the construction of nine point scheme, both vertex unknowns and cell-centered unknowns are introduced, and the vertex unknowns are usually eliminated by using the interpolation of neighboring cell-centered unknowns, which often leads to lose accuracy. Instead of using interpolation, here we propose a different method of calculating the vertex unknowns of nine point scheme, which are solved independently on a new generated mesh. This new mesh is a Vorono? mesh based on the vertexes of primary mesh and some additional points on the interface. The advantage of this method is that it is particularly suitable for solving diffusion problems with discontinuous coefficients on highly distorted meshes, and it leads to a symmetric positive definite matrix. We prove that the method has first-order convergence on distorted meshes. Numerical experiments show that the method obtains nearly second-order accuracy on distorted meshes.展开更多
基金This work was supported by China“National Key Program for Developing Basic Sciences”G1999032801the National Natural Science Foundation of China(Grant No.19932010)the Foundation of CAEP(20020652).
文摘A kind of the general finite difference schemes with intrinsic parallelism for the boundary value problem of the quasilinear parabolic system is studied without assuming heuristically that the original boundary value problem has the unique smooth vector solution. By the method of a priori estimation of the discrete solutions of the nonlinear difference systems, and the interpolation formulas of the various norms of the discrete functions and the fixed-point technique in finite dimensional Euclidean space, the existence and uniqueness of the discrete vector solutions of the nonlinear difference system with intrinsic parallelism are proved. Moreover the unconditional stability of the general finite difference schemes with intrinsic parallelism is justified in the sense of the continuous dependence of the discrete vector solution of the difference schemes on the discrete data of the original problems in the discrete W 2 (2,1) norms. Finally the convergence of the discrete vector solutions of the certain difference schemes with intrinsic parallelism to the unique generalized solution of the original quasilinear parabolic problem is proved.
基金the National Natural Science Foundation of China(Great Nos.10702010,10431050)the Foundation of China Academy of Engineering Physics(Great No.2007B09008)+1 种基金Foundation of Laboratory of Computational Physics(Great No.9140C6902010805)the Basic Research Project of National Defence(Great No.A1520070074)
文摘A new Lagrangian cell-centered scheme for two-dimensional compressible flows in planar geometry is proposed by Maire et al.The main new feature of the algorithm is that the vertex velocities and the numerical fluxes through the cell interfaces are all evaluated in a coherent manner contrary to standard approaches.In this paper the method introduced by Maire et al.is extended for the equations of Lagrangian gas dynamics in cylindrical symmetry.Two different schemes are proposed,whose difference is that one uses volume weighting and the other area weighting in the discretization of the momentum equation.In the both schemes the conservation of total energy is ensured,and the nodal solver is adopted which has the same formulation as that in Cartesian coordinates.The volume weighting scheme preserves the momentum conservation and the area-weighting scheme preserves spherical symmetry.The numerical examples demonstrate our theoretical considerations and the robustness of the new method.
基金the National Basic Research Program(Grant No.2005CB321703)the National Nature Science Foundation of China(Grant No.90718029)the Basic Research Project of National Defense(Grant No.A1520070074)
文摘In the construction of nine point scheme, both vertex unknowns and cell-centered unknowns are introduced, and the vertex unknowns are usually eliminated by using the interpolation of neighboring cell-centered unknowns, which often leads to lose accuracy. Instead of using interpolation, here we propose a different method of calculating the vertex unknowns of nine point scheme, which are solved independently on a new generated mesh. This new mesh is a Vorono? mesh based on the vertexes of primary mesh and some additional points on the interface. The advantage of this method is that it is particularly suitable for solving diffusion problems with discontinuous coefficients on highly distorted meshes, and it leads to a symmetric positive definite matrix. We prove that the method has first-order convergence on distorted meshes. Numerical experiments show that the method obtains nearly second-order accuracy on distorted meshes.
