对国内秸秆利用现状的思考

针对国内秸秆利用的现状,剖析了问题产生的原因,并提出了针对性的措施,指出只有各地采取因地制宜的措施才能够从根本上解决秸秆焚烧等污染环境和浪费资源的问题。     

A mathematical verification of the reinforced-matrix hypothesis using the Mori-Tanaka theory

This article presents a theoretical verification of the reinforced-matrix hypothesis derived from tensor equations, σ ^W = σ ^f + σ ^m and ε ^W = ε ^f = ε ^m (Wood Sci Technol 32:171–182, 1998; Wood Sci Technol 33:311–325, 1999; J Biomech Eng 124:432–440, 2002), using classical Mori-Tanaka theory on the micromechanics of fiber-reinforced materials (Acta Metall 21:571–574, 1973; Micromechanics — dislcation and inclusions (in Japanese), pp 141–147, 1976). The Mori-Tanaka theory was applied to a small fragment of the cell wall undergoing changes in its physical state, such as those arising from sorption of moisture, maturation of wall components, or action of an external force, to obtain 〈σ ^A〉_D = ϕ·〈σ ^F〉_I + (1−ϕ)·〈σ ^M〉_D−I. When the constitutive equation of each constituent material was applied to the equation 〈σ ^A〉_D = ϕ·〈σ ^F〉_I + (1−ϕ)·〈σ ^M〉_D−I, the equations σ ^W = σ ^f + σ ^m and ε ^W = ε ^f = ε ^m were derived to lend support to the concept that two main phases, the reinforcing cellulose microfibril and the lignin-hemicellulose matrix, coexist in the same domain. The constitutive equations for the cell wall fragment were obtained without recourse to additional parameters such as Eshelby’s tensor S and Hill’s averaged concentration tensors A^F and A^M. In our previous articles, the coexistence of two main phases and σ ^W = σ ^f + σ ^m and ε ^W = ε ^f =ε ^m had been taken as our starting point to formulate the behavior of wood fiber with multilayered cell walls. The present article provides a rational explanation for both concepts.     

丝素-壳聚糖共混膜的物理性能和细胞相容性探讨

采用共混法制备丝素-壳聚糖共混膜,并测定其力学性能,结果表明各种配比的丝素-壳聚糖共混膜均具有良好的机械性能,能够克服纯丝素膜刚而脆的弱点。扫描电镜显示纯丝素膜SF、共混膜SCP1表面致密光滑,SCG2、SCP2两种共混膜都有明显突起,而共混膜SCG1的表面凹凸不平。细胞培养结果显示,SCG1、SCG2、SCP1和SCP2等4种共混膜的细胞毒性都在0、1级,细胞增殖率在85%~105%之间,细胞附着率在24 h的达到90%以上,说明各种配比的丝素-壳聚糖共混膜都具有良好的细胞相容性,基本符合生物材料的应用要求。     

Decellularization of Extracellular Matrix from Equine Skeletal Muscle

Equine represents an attractive animal model for musculoskeletal tissue diseases, exhibiting much similarity to the injuries that occur in humans. Cell therapy and tissue bioengineering have been widely used as a therapeutic alternative by regenerative medicine in musculoskeletal diseases. Thus, the aim of this study was to produce an acellular biomaterial of equine skeletal muscle and to evaluate its effectiveness in supporting the in vitro culture of equine induced pluripotency stem cells (iPSCs). Biceps femoris samples were frozen at −20°C for 4 days and incubated in 1% sodium dodecyl sulfate (SDS), 5 mM EDTA + 50 mM Tris and 1% Triton X-100; the effectiveness of the decellularization was evaluated by the absence of remnant nuclei (histological and 4′,6-diamidino-2-phenylindole [DAPI] analysis), preservation of extracellular matrix (ECM) proteins (immunofluorescence and immunohistochemistry) and organization of ECM ultrastructure (scanning electron microscopy). Decellularized samples were recellularized with iPSCs at the concentration of 50,000 cells/cm² and cultured in vitro for 9 days, and the presence of the cells in the biomaterial was evaluated by histological analysis and presence of nuclei. Decellularized biomaterial showed absence of remnant nuclei and muscle fibers, as well as the preservation of ECM architecture, vascular network and proteins, laminin, fibronectin, elastin, collagen III and IV. After cellularization, iPSC nuclei were present at 9 days after incubation, indicating the decellularized biomaterial-supported iPSC survival. It is concluded that the ECM biomaterial produced from the decellularized equine skeletal muscle has potential for iPSC adhesion, representing a promising biomaterial for regenerative medicine in the therapy of musculoskeletal diseases.     

热力干燥中热湿不稳定物质质量的保护

生物物料和食品在热力干燥过程中的质量退化主要是由其热湿不稳定特性导致的。因此为保持干燥后产品的质量,常采用较温和的干燥条件,以及减少物料在高含水率阶段的干燥时间。为观察其对物料品质指标的影响,对面包酵母和清蛋白两种物质在不同的干燥条件下进行了热力干燥试验。结果显示：欲获得更好的热力干燥后产品品质,对热、湿耐受性不同的生物物质应采用不同的保护措施。