摘要：Mesenchymal stem/progenitor cells (MSC/MPC) from a variety of tissue sources (bone marrow, adipose tissue, fat pads, synovial membranes, synovial fluid, skin, muscle and periosteal tissue) have been widely applied for tissue engineering applications to generate replacements for injured or degenerated tissues. Alternatively, they have also been injected as free cells in an attempt to facilitate in vivo repair. Nearly all studies reported have used mixed cell populations of MSC/MPC, usually defined by cell surface phenotypes and/or functional ability to differentiate towards multiple cell lineages. Using more detailed cell surface phenotyping and limiting dilution approaches to isolate individual MSC/MPC clones have indicated that such mixed cell populations are very heterogeneous. In addition subsets of cells from different sources may have epigenetic modifications. While it is clear that MSC/MPC cells exhibit heterogeneity, the question of why this is the case has not been well addressed. This review will address some of these issues, as well as provide some insights into the implications when using such diverse cells for tissue engineering applications.

摘要：In this work, the unified fracture design （UFD） is extended for the first time to the fractured horizontal wells in heterogeneous closed box-shaped tight gas reservoirs. Utilizing the direct boundary element method and influence function, the dimensionless fracture productivity index is obtained and expressed in the function of proppant volume and fracture geometry at the pseu- do-steady state. With the iterative method, the effectively propped permeability, kfe, is corrected using the i^-situ Reynolds number, NRe. The goal of this paper is to present a new UFD extension to design the proppant volume and the optimal fracture geometry. The results show that there exists an optimal proppant volume for a certain reservoir. The small aspect ratio （yJXe） and high permeability reservoirs need short and wide fractures to diminish the non-Darcy effect. On the contrary, long and narrow fractures are required for the large aspect ratio and low permeability reservoirs. A small proppant volame is prone to creating long fractures, while a relatively large proppant volume creates wide fractures. The new extension can be used to evaluate the previous fracture parameters and design the following fracture parameters of the fractured horizontal well in heterogeneous tight gas reservoirs, with the non-Darcy effect taken into account.

摘要：Landscape ecological pattern mode emphasized the control and influence of landscape space pattern on the process, and through the change of pattern, it could preserve the health and safety of landscape function flow. The study methods of landscape ecological pattern included static analysis and dynamic analysis. Establishing integrated ecological infrastructure by utilizing ecological security pattern methods was the basis for urban ecological environment planning, which provided theoretical foundation and practicable means for ecological city construction, and which could be applied in the analysis of basic characteristics of urban landscape ecology and current status of urban landscape security pattern, and in the planning of urban landscape ecological pattern. By taking Xi'an City for example, it could analyze eco-environment and composition of landscape ecological pattern in Xi'an by adopting static analysis. It had concluded the distribution and features of ecological bases, corridors and patches in Xi'an. Meanwhile, it had made a summarization of fragmentation of base pattern, artificialization of corridors, and decentralization of patches at built up areas, hoping to provide theoretical basis for researches and completion of ecological pattern in Xi'an City.