Research progress on surface antigen 1 (SAG1) of Toxoplasma gondii

Toxoplasma gondii is an obligate intracellular parasitic protozoan that has a wide host range and causes a zoonotic parasitosis called toxoplasmosis. This infection causes significant morbidity, costs for care and loss of productivity and suffering. The most effective measures to minimize this parasite’s harm to patients are prompt diagnosis and treatment and preventing infection. A parasite surface antigen, SAG1, is considered an important antigen for the development of effective diagnostic tests or subunit vaccines. This review covers several aspects of this antigen, including its gene structure, contribution to host invasion, mechanisms of the immune responses and its applications for diagnosis and vaccine development. This significant progress on this antigen provides foundations for further development of more effective and precise approaches to diagnose toxoplasmosis in the clinic, and also have important implications for exploring novel measures to control toxoplasmosis in the near future

Time-delay signature suppression in delayed-feedback semiconductor lasers as a paradigm for feedback control in complex physiological networks

Physiological phenomena are often accompanied by time delay effects which may lead to oscillatory and even chaotic dynamics in their behaviors. Analogous dynamics is found in semiconductor lasers subject to delayed optical feedback where the dynamics typically includes a signature of the time delay. In many applications of semiconductor lasers, the suppression of the time delay signature is essential for applications and hence several approaches have been adopted for that purpose. In this paper experimental results are presented wherein photonic filters are utilized in order to suppress time-delay signatures in semiconductor lasers subject to delayed optical feedback effects. Two kinds of semiconductor lasers are used: discrete mode semiconductor lasers and vertical-cavity surfaceemitting lasers (VCSELs). It is shown that, by the use of photonic filters, complete suppression of the time-delay signature may be affected in discrete mode semiconductor lasers but that a remnant of the signature persists for VCSEL

Quantifying sudden changes in dynamical systems using symbolic networks

We characterise the evolution of a dynamical system by combining two well-known complex systems' tools, namely, symbolic ordinal analysis and networks. From the ordinal representation of a time-series we construct a network in which every node weights represents the probability of an ordinal patterns (OPs) to appear in the symbolic sequence and each edges weight represents the probability of transitions between two consecutive OPs. Several network-based diagnostics are then proposed to characterize the dynamics of different systems: logistic, tent and circle maps. We show that these diagnostics are able to capture changes produced in the dynamics as a control parameter is varied. We also apply our new measures to empirical data from semiconductor lasers and show that they are able to anticipate the polarization switchings, thus providing early warning signals of abrupt transitions.Comment: 18 pages, 9 figures, to appear in New Journal of Physic