Boundary information inflow enhances correlation in flocking

The most conspicuous trait of collective animal behaviour is the emergence of highly ordered structures. Less obvious to the eye, but perhaps more profound a signature of self-organization, is the presence of long-range spatial correlations. Experimental data on starling flocks in 3d show that the exponent ruling the decay of the velocity correlation function, C(r) ~ 1/r^\gamma, is extremely small, \gamma << 1. This result can neither be explained by equilibrium field theory, nor by off-equilibrium theories and simulations of active systems. Here, by means of numerical simulations and theoretical calculations, we show that a dynamical field applied to the boundary of a set of Heisemberg spins on a 3d lattice, gives rise to a vanishing exponent \gamma, as in starling flocks. The effect of the dynamical field is to create an information inflow from border to bulk that triggers long range spin wave modes, thus giving rise to an anomalously long-ranged correlation. The biological origin of this phenomenon can be either exogenous - information produced by environmental perturbations is transferred from boundary to bulk of the flock - or endogenous - the flock keeps itself in a constant state of dynamical excitation that is beneficial to correlation and collective response

One year study of efficacy and safety of infliximab in the treatment of patients with ocular and neurological Behçet's disease refractory to standard immunosuppressive drugs

Abstract The aim of the study was to assess the long-term efficacy and safety of Infliximab therapy in the treatment of patients with Behçet’s disease refractory to standard immunosuppressive agents. Twenty-one patients that did not respond to corticosteroids and to at least one immunosuppressant (cyclosporin, methotrexate, azathioprine, cyclophosphamide) for the presence of ocular and/or CNS involvement were enrolled. Eighteen patients completed the study up to 54 weeks. Stable doses of prednisone (<10 mg/day) were permitted, immunosuppressants were discontinued at least 4 weeks prior baseline visit. The patients received three infusions of 5 mg/kg Infliximab (at weeks 0, 2 and 6) and then infusions of 5 mg/kg Infliximab every 8 weeks. At each visit data on clinical symptoms, response to therapy and adverse events were collected. The primary outcome of interest was to assess the clinical efficacy (total or partial recovery) of infliximab. Secondary end points were to evaluate quality of life and to monitor the safety of the drug. Eighteen patients achieved a total remission. Two patients achieved a partial remission and relapsed after 3 months from discontinuation of therapy. Infliximab was well tolerated throughout the study. A case of non-Hodgkin lymphoma was observed within 6 months. Minor side effects were headache, dizziness, tachycardia that regressed spontaneously and did not entail interruption. Anti-nuclear antibodies were not detected during the period of observation

Uphill in reaction-diffusion multi-species interacting particles systems

We study reaction-diffusion processes with multi-species of particles and hard-core interaction. We add boundary driving to the system by means of external reservoirs which inject and remove particles, thus creating stationary currents. We consider the condition that the time evolution of the average occupation evolves as the discretized version of a system of coupled diffusive equations with linear reactions. In particular, we identify a specific one-parameter family of such linear reaction-diffusion systems where the hydrodynamic limit behaviour can be obtained by means of a dual process. We show that partial uphill diffusion is possible for the discrete particle systems on the lattice, whereas it is lost in the hydrodynamic limit.Comment: 26 pages, 3 figure

Targeting IL-6 signalling in early rheumatoid arthritis is followed by Th1 and Th17 suppression and Th2 expansion

OBJECTIVES: To investigate the in vitro and ex-vivo effect of IL-6 inhibition on the balance between Th1, Th2, Th17 and Treg cells. METHODS: Ten consecutive adult patients with active early rheumatoid arthritis (ERA) and ten healthy volunteers were included in the study. The percentages of Th1, Th2, Th17 and Treg cells were analysed by flow cytometry in the peripheral blood mononuclear cells obtained from controls and from RA patients at the time of first evaluation and just before the third TCZ infusion. The in vitro effect of TCZ on the different subsets of CD4+ T cells and the expression levels of Th1, Th2, Th17 and Treg-related cytokines was also assessed. RESULTS: Treatment with TCZ, both ex vivo and in vitro, resulted in a significant reduction of the percentage of Th1, Th17 and Treg cells with a concomitant significant increase of Th2 cell subsets. The reduction of the different subsets of T lymphocytes was associated with an intense staining with Annexin V, suggesting an apoptotic-related cell reduction. A significant decrease of Th1, Th17 and Treg cytokines and a concomitant increase of IL-4 was also observed after TCZ treatment in PBMC isolated from RA patients. CONCLUSIONS: TCZ could modify the immune imbalance in RA inducing apoptosis of Th1, Th17 and Treg cells and promoting the appearance of a Th2 response

Are Toll-Like Receptors and Decoy Receptors Involved in the Immunopathogenesis of Systemic Lupus Erythematosus and Lupus-Like Syndromes?

In this paper we focus our attention on the role of two families of receptors, Toll-like receptors (TLR) and decoy receptors (DcR) involved in the generation of systemic lupus erythematosus (SLE) and lupus-like syndromes in human and mouse models. To date, these molecules were described in several autoimmune disorders such as rheumatoid arthritis, antiphospholipids syndrome, bowel inflammation, and SLE. Here, we summarize the findings of recent investigations on TLR and DcR and their role in the immunopathogenesis of the SLE

A case-driven hypothesis for multi-stage crack growth mechanism in fourth-generation ceramic head fracture

Background Ceramic bearings are used in total hip arthroplasty due to their excellent wear behaviour and biocompatibility. The major concern related to their use is material brittleness, which significantly impacts on the risk of fracture of ceramic components. Fracture toughness improvement has contributed to the decrease in fracture rate, at least of the prosthetic head. However, the root cause behind these rare events is not fully understood. This study evaluated head fracture occurrence in a sizeable cohort of patients with fourth-generation ceramic-on-ceramic implants and described the circumstances reported by patients in the rare cases of head fracture. Methods The clinical survivorship of 29,495 hip prostheses, with fourth-generation ceramic bearings, was determined using data from a joint replacement registry. The average follow-up period was 5.2 years (range 0.1-15.6). Retrieval analysis was performed in one case for which the ceramic components were available. Results Clinical outcomes confirmed the extremely low fracture rate of fourth-generation ceramic heads: only two out of 29,495 heads fractured. The two fractures, both involving 36 mm heads, occurred without a concurrent or previous remarkable trauma. Considering the feature of the fractured head, a multi-stage crack growth mechanism has been hypothesized to occur following damage at the head-neck taper interface. Conclusions Surgeons must continue to pay attention to the assembly of the femoral head: achieving a proper head seating on a clean taper is a prerequisite to decrease the risk of occurrence of any damage process within head-neck junction, which may cause high stress concentration at the contact surface, promoting crack nucleation and propagation even in toughened ceramics

Dynamical maximum entropy approach to flocking

Peer reviewedPublisher PD