Silibinin is the major pharmacologically active compound of silymarin, the Silybum marianum fruit extract. Hepatoprotective activities of silibinin/silymarin are well-known, and recent studies demonstrated their anti-inflammatory and anti-carcinogenic effects which are due to inhibition of the transcription factor NF-kappaB. Based on this knowledge, we hypothesized that silibinin could be effective in the treatment of multiple sclerosis (MS) and so we tested its immunosuppressive effect in experimental autoimmune encephalomyelitis (EAE), the MS animal model. The process of spinal cord demyelination and inflammation were observed and T cell migration was determined by FACS analysis. The results showed that silibinin significantly reduced the histological signs of demyelination and inflammation in EAE. Since cytokines play an important role in inflammatory disease, the proliferative response and cytokine production were examined in lymphocytes from spleens and lymph nodes. We demonstrated that silibinin Ag-nonspecifically down-regulated the secretion of pro-inflammatory Th1 cytokines and up-regulated the anti-inflammatory Th2 cytokines in vitro. Silibinin also dose-dependently inhibited the production of Th1 cytokines ex vivo. These results indicate that silibinin is both immunosuppressive and immunomodulatory.
Shear wall systems in high-rise apartments are governed by the fl exural behaviour of members such as a cantilever beam. The installation of the damper-brace system in a structure governed by fl exural behaviour is not suitable. Because of the relatively high lateral stiffness of the shear wall, a load is not concentrated on the brace and the brace cannot perform the role of a damping device. In this paper, a friction damper that applies the fl exibility of a shear wall is proposed in order to reduce the deformation of the structure. To evaluate the performance of the proposed friction damper, a nonlinear time history analysis is executed by the SeismoStruct analysis program, and a multiple vertical linear element model is used for simulating fl exural behaviour of the shear wall. It is found that the control performance of the proposed friction damper is superior to that of a coupled wall with a rigid beam. In conclusion, this study verifi ed that the optimal control performance of the proposed friction damper is equal to 45% of the maximum shear force induced in the middle fl oor beam with the rigid beam.
SUMMARYA systematic and improved design procedure for sliding mode control (SMC) of seismically excited civil structures with saturation problem is provided in this paper. In order to restrict the control force to a certain level, a procedure for determining the upper limits of the control forces for single or multiple control units is proposed based on the design response spectrum of external loads. Further, an e cient procedure using the LQR method for determining sliding surfaces appropriate for di erent controller types is provided through the parametric evaluation of the dynamic characteristics of sliding surfaces in terms of SMC controller performance. Finally, a systematic design procedure for SMC required to achieve a given performance level is provided and its e ectiveness is veriÿed by applying it to multi-degree-of-freedom (MDOF) systems.
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