Search

To explore the strength characteristics of anisotropic rocks caused by mineral directional arrangement during progressive failure process, biotite quartz schist was taken as an example, and triaxial compression tests were carried out on samples with schistosity angles of 0°, 45° and 90°. The macro and micro failure characteristics and progressive failure strength index of the specimens were analyzed, and the differences with other types of anisotropic rock were discussed. The results show that the failure characteristics of biotite quartz schist are closely related to its schistosity. With the schistosity angle increasing from 0° to 90°, the main macro and micro fracture modes of the specimens change from tensile to shear, and then to co-existence of tensile and shear. The strength characteristic values of biotite quartz schist show significant anisotropy. With the increase of schistosity angle, the strengthening effect caused by confining pressure increase on the strength characteristic values weakens, but the change of the strength value has a trend of acceleration. The anisotropic variation law of the ratio of strength characteristic value is not obvious, which gradually weakens and even disappears under high confining pressure. The fracture modes, variations of strength characteristic values and their ratios of anisotropic rocks with directional arrangement of minerals are different from those of rocks with stratified structure. A thorough understanding of the mechanical properties of rocks with directional arrangement of minerals will be helpful to guide the related engineering practice.

Neural stem cell (NSC) transplantation is a promising strategy for replacing lost neurons following spinal cord injury. However, the survival and differentiation of transplanted NSCs is limited, possibly owing to the neurotoxic inflammatory microenvironment. Because of the important role of glucose metabolism in M1/M2 polarization of microglia/macrophages, we hypothesized that altering the phenotype of microglia/macrophages by regulating the activity of aldose reductase (AR), a key enzyme in the polyol pathway of glucose metabolism, would provide a more beneficial microenvironment for NSC survival and differentiation. Here, we reveal that inhibition of host AR promoted the polarization of microglia/macrophages toward the M2 phenotype in lesioned spinal cord injuries. M2 macrophages promoted the differentiation of NSCs into neurons in vitro. Transplantation of NSCs into injured spinal cords either deficient in AR or treated with the AR inhibitor sorbinil promoted the survival and neuronal differentiation of NSCs at the injured spinal cord site and contributed to locomotor functional recovery. Our findings suggest that inhibition of host AR activity is beneficial in enhancing the survival and neuronal differentiation of transplanted NSCs and shows potential as a treatment of spinal cord injury., Competing Interests: None