Avalanches in Breakdown and Fracture Processes

We investigate the breakdown of disordered networks under the action of an increasing external---mechanical or electrical---force. We perform a mean-field analysis and estimate scaling exponents for the approach to the instability. By simulating two-dimensional models of electric breakdown and fracture we observe that the breakdown is preceded by avalanche events. The avalanches can be described by scaling laws, and the estimated values of the exponents are consistent with those found in mean-field theory. The breakdown point is characterized by a discontinuity in the macroscopic properties of the material, such as conductivity or elasticity, indicative of a first order transition. The scaling laws suggest an analogy with the behavior expected in spinodal nucleation.Comment: 15 pages, 12 figures, submitted to Phys. Rev. E, corrected typo in authors name, no changes to the pape

Estimation of Ankle Joint Torque and Angle Based on S-EMG Signal for Assistive Rehabilitation Robots

Surface Electromyography (S-EMG) has shown the advantages of robotic rehabilitation. Robotic rehabilitation can be significantly improved if the intended body movement of the patients can be well identified. In this chapter, we first use the SVM classifier to identify the intended motion patterns, which are plantarflexion and dorsiflexion, by using three wireless EMG sensors placed at the tibialis anterior, gastrocnemius lateralis and gastrocnemius medialis muscles. To estimate the ankle joint torque as well as the joint angle for both plantarflexion and dorsiflexion, this chapter also develops nonlinear mathematical models for joint torque estimation and utilises Swarm Techniques to identify model parameters for each movement pattern of the ankle. During rehabilitation, once the intended motion is recognised, the activation functions extracted from an individual associated EMG channel can be used to estimate both the torque and angle by using the established nonlinear models. Experimental results demonstrated the effectiveness of the proposed approach

CD82 controls CpG-dependent TLR9 signaling.

The tetraspanin CD82 is a potent suppressor of tumor metastasis and regulates several processes including signal transduction, cell adhesion, motility, and aggregation. However, the mechanisms by which CD82 participates in innate immunity are unknown. We report that CD82 is a key regulator of TLR9 trafficking and signaling. TLR9 recognizes unmethylated cytosine-phosphate-guanine (CpG) motifs present in viral, bacterial, and fungal DNA. We demonstrate that TLR9 and CD82 associate in macrophages, which occurs in the endoplasmic reticulum (ER) and post-ER. Moreover, CD82 is essential for TLR9-dependent myddosome formation in response to CpG stimulation. Finally, CD82 modulates TLR9-dependent NF-κB nuclear translocation, which is critical for inflammatory cytokine production. To our knowledge, this is the first time a tetraspanin has been implicated as a key regulator of TLR signaling. Collectively, our study demonstrates that CD82 is a specific regulator of TLR9 signaling, which may be critical in cancer immunotherapy approaches and coordinating the innate immune response to pathogens.-Khan, N. S., Lukason, D. P., Feliu, M., Ward, R. A., Lord, A. K., Reedy, J. L., Ramirez-Ortiz, Z. G., Tam, J. M., Kasperkovitz, P. V., Negoro, P. E., Vyas, T. D., Xu, S., Brinkmann, M. M., Acharaya, M., Artavanis-Tsakonas, K., Frickel, E.-M., Becker, C. E., Dagher, Z., Kim, Y.-M., Latz, E., Ploegh, H. L., Mansour, M. K., Miranti, C. K., Levitz, S. M., Vyas, J. M. CD82 controls CpG-dependent TLR9 signaling.This work was supported by U.S. National Institutes of Health, National Institute of Allergy and Infectious Diseases Grants R01 AI092084 and R01 AI097519 (to J.M.V.) and R01 AI025780 and R01 AI139615 (to S.M.L.). This work was also supported by the Francis Crick Institute, which receives its core funding from Cancer Research UK (FC001076), the UK Medical Research Council (FC001076), and the Wellcome Trust (FC001076)