Sandpile model on an optimized scale-free network on Euclidean space

Deterministic sandpile models are studied on a cost optimized Barab\'asi-Albert (BA) scale-free network whose nodes are the sites of a square lattice. For the optimized BA network, the sandpile model has the same critical behaviour as the BTW sandpile, whereas for the un-optimized BA network the critical behaviour is mean-field like.Comment: Five pages, four figure

Self-organisation to criticality in a system without conservation law

We numerically investigate the approach to the stationary state in the nonconservative Olami-Feder-Christensen (OFC) model for earthquakes. Starting from initially random configurations, we monitor the average earthquake size in different portions of the system as a function of time (the time is defined as the input energy per site in the system). We find that the process of self-organisation develops from the boundaries of the system and it is controlled by a dynamical critical exponent z~1.3 that appears to be universal over a range of dissipation levels of the local dynamics. We show moreover that the transient time of the system $t_{tr}$ scales with system size L as $t_{tr} \sim L^z$. We argue that the (non-trivial) scaling of the transient time in the OFC model is associated to the establishment of long-range spatial correlations in the steady state.Comment: 10 pages, 6 figures; accepted for publication in Journal of Physics

Design Proposal for a Portable Elbow Exoskeleton

Exoskeleton based rehabilitation for post-stroke recovery is being aggressively pursued due to unavailability of adequate number of caregivers and huge investment for the manual treatment [1]. The structural framework for providing different training exercises is not similar for all exoskeletons and there is no standardized protocol for rehabilitation following stroke [2]. Various approaches have been undertaken to come up with customized exoskeleton design for implementing a specific type of exercise. Though a few exoskeletons have proved to be beneficial in terms of clinical outcomes, there is still a long way to go before a useful rehabilitation device becomes acceptable to the users. After reviewing the 46 exoskeletons (commercial or prototypes) [3], two key requirements can be considered for the design of an exoskeleton; the structural parameter which decides the size, weight and the ease of control and the other is the nature of rehabilitation therapy which defines the type and intensity of the exercises performed during training

A novel hardware approach to integrating active and passive rehabilitation in a single exoskeleton

The proposed exoskeleton is based on the elbow joint where patients can have active and passive rehabilitation in a single structure without changing its configuration. The structural formation of the exoskeleton has been designed in such a way that it offers two working regions namely; actuator based active rehabilitation in the first phase and passive rehabilitation in the second phase. The solution for integrating these two phases has been implemented using an innovative passive locking mechanism which uses a spring-based system for transformation. The stiffness of the spring is utilized to switch between active and passive rehabilitation regions. Besides this there are some other advantages this exoskeleton offers such as reduction of the actuation torque as well as ease of control. The paper is divided into three parts: the first part describes the existing designs, the second part gives an overview of the developed mechanism with structural description and the last part provides the solution with technical specification

A mechanism for elbow exoskeleton for customised training.

It is well proven that repetitive extensive training consisting of active and passive therapy is effective for patients suffering from neuromuscular deficits. The level of difficulty in rehabilitation should be increased with time to improve the neurological muscle functions. A portable elbow exoskeleton has been designed that will meet these requirements and potentially offers superior outcomes than human-assisted training. The proposed exoskeleton can provide both active and passive rehabilitation in a single structure without changing its configuration. The idea is to offer three levels of rehabilitation; namely active, passive and stiffness control in a single device using a single actuator. The mechanism also provides higher torque to weight ratio making it an energy efficient mechanism

Weighted Scale-free Networks in Euclidean Space Using Local Selection Rule

A spatial scale-free network is introduced and studied whose motivation has been originated in the growing Internet as well as the Airport networks. We argue that in these real-world networks a new node necessarily selects one of its neighbouring local nodes for connection and is not controlled by the preferential attachment as in the Barab\'asi-Albert (BA) model. This observation has been mimicked in our model where the nodes pop-up at randomly located positions in the Euclidean space and are connected to one end of the nearest link. In spite of this crucial difference it is observed that the leading behaviour of our network is like the BA model. Defining link weight as an algebraic power of its Euclidean length, the weight distribution and the non-linear dependence of the nodal strength on the degree are analytically calculated. It is claimed that a power law decay of the link weights with time ensures such a non-linear behavior. Switching off the Euclidean space from the same model yields a much simpler definition of the Barab\'asi-Albert model where numerical effort grows linearly with $N$.Comment: 6 pages, 6 figure

Tuning and Locking the Localized Surface Plasmon Resonances of CuS (Covellite) Nanocrystals by an Amorphous CuPdxS Shell

[Image: see text] We demonstrate the stabilization of the localized surface plasmon resonance (LSPR) in a semiconductor-based core–shell heterostructure made of a plasmonic CuS core embedded in an amorphous-like alloyed CuPd(x)S shell. This heterostructure is prepared by reacting the as-synthesized CuS nanocrystals (NCs) with Pd(2+) cations at room temperature in the presence of an electron donor (ascorbic acid). The reaction starts from the surface of the CuS NCs and proceeds toward the center, causing reorganization of the initial lattice and amorphization of the covellite structure. According to density functional calculations, Pd atoms are preferentially accommodated between the bilayer formed by the S–S covalent bonds, which are therefore broken, and this can be understood as the first step leading to amorphization of the particles upon insertion of the Pd(2+) ions. The position and intensity in near-infrared LSPRs can be tuned by altering the thickness of the shell and are in agreement with the theoretical optical simulation based on the Mie–Gans theory and Drude model. Compared to the starting CuS NCs, the amorphous CuPd(x)S shell in the core–shell nanoparticles makes their plasmonic response less sensitive to a harsh oxidation environment (generated, for example, by the presence of I(2))

Mycobacterium tuberculosis Drives Expansion of Low-Density Neutrophils Equipped With Regulatory Activities

In human tuberculosis (TB) neutrophils represent the most commonly infected phagocyte but their role in protection and pathology is highly contradictory. Moreover, a subset of low-density neutrophils (LDNs) has been identified in TB, but their functions remain unclear. Here, we have analyzed total neutrophils and their low-density and normal-density (NDNs) subsets in patients with active TB disease, in terms of frequency, phenotype, functional features, and gene expression signature. Full-blood counts from Healthy Donors (H.D.), Latent TB infected, active TB, and cured TB patients were performed. Frequency, phenotype, burst activity, and suppressor T cell activity of the two different subsets were assessed by flow cytometry while NETosis and phagocytosis were evaluated by confocal microscopy. Expression analysis was performed by using the semi-quantitative RT-PCR array technology. Elevated numbers of total neutrophils and a high neutrophil/lymphocyte ratio distinguished patients with active TB from all the other groups. PBMCs of patients with active TB disease contained elevated percentages of LDNs compared with those of H.D., with an increased expression of CD66b, CD33, CD15, and CD16 compared to NDNs. Transcriptomic analysis of LDNs and NDNs purified from the peripheral blood of TB patients identified 12 genes differentially expressed: CCL5, CCR5, CD4, IL10, LYZ, and STAT4 were upregulated, while CXCL8, IFNAR1, NFKB1A, STAT1, TICAM1, and TNF were downregulated in LDNs, as compared to NDNs. Differently than NDNs, LDNs failed to phagocyte live Mycobacterium tuberculosis (M. tuberculosis) bacilli, to make oxidative burst and NETosis, but caused significant suppression of antigen-specific and polyclonal T cell proliferation which was partially mediated by IL-10. These insights add a little dowel of knowledge in understanding the pathogenesis of human TB