Dynamical behaviour of epidemiological models with sub-optimal immunity and nonlinear incidence

In this paper we analyze the dynamics of two families of epidemiological models which correspond to transitions from the SIR (susceptible-infectious-resistant) to the SIS (susceptible-infectious-susceptible) frameworks. In these models we assume that the force of infection is a nonlinear function of density of infectious individuals, I. Conditions for the existence of backwards bifurcations, oscillations and Bogdanov-Takens points are give

Parvovirus B19: Insights and implication for pathogenesis, prevention and therapy

Parvovirus B19 (B19V) is a small ssDNA non-enveloped virus, member of Parvoviridae family. The infection is widely diffused and is responsible for a broad range of clinical manifestations including fifth disease in children, transient aplastic crisis in patients with haematological disorders, non-immune hydrops fetalis in pregnant women, persistent anaemia in immunocompromised patients, arthropathy and inflammation of various other tissues. B19V infects and replicates in erythroid progenitor cells (EPCs) in the bone marrow. The depletion of infected EPCs represents the pathogenetic mechanisms of some haematological B19V-associate diseases. Following a primary infection, the virus can establish lifelong persistence in several tissues. Currently, the pathological potential of persistent virus on the cellular signalling pathways remains unclear. In non-erythroid tissues, the infection is usually, abortive, and the virus seems to exert its pathological role through indirect mechanisms, such as induction of inflammatory and autoimmune processes, or through virus-induced apoptosis mediated by viral proteins. In addition to the diseases for which the etiological role of B19V has been fully demonstrated, there are several clinical conditions, including autoimmune diseases, that are presumably, but not certainly, associated with B19V infection. In this review, we describe recent findings that may give us new insight into the pathogenic role of B19V in systemic sclerosis, an autoimmune disease of unknown multifactorial aetiology. Furthermore, we describe the latest findings on the intrauterine B19V infections. Moreover, since there are some ongoing interesting studies focused on vaccine development and antiviral drug discovery for the prevention and treatment of parvovirus B19 infection we described some advances in this field of research

Opto-mechanical probe for combining atomic force microscopy and optical near-field surface analysis

We have developed a new easy-to-use probe that can be used to combine atomic force microscopy (AFM) and scanning near-field optical microscopy (SNOM). We show that, using this device, the evanescent field, obtained by total internal reflection conditions in a prism, can be visualized by approaching the surface with the scanning tip. Furthermore, we were able to obtain simultaneous AFM and SNOM images of a standard test grating in air and in liquid. The lateral resolution in AFM and SNOM mode was estimated to be 45 and 160 nm, respectively. This new probe overcomes a number of limitations that commercial probes have, while yielding the same resolution. (C) 2014 Optical Society of Americ

Tandem chemiluminescence-flow injection analysis for dimethoate determination

This work was supported by the Ministry of Education and Science of Spain (Project CTM2006-11991) and FEDER funds.Catalá Icardo, M.; López Paz, JL.; Choves Barón, C. (2010). Tandem chemiluminescence-flow injection analysis for dimethoate determination. Luminescence. 25:235-236. https://doi.org/10.1002/bio.1217S2352362

Glutathione-Induced Release of Zeatin From Functionalized Gold Nanovectors

The paper shows our preliminary results on the different spectroscopic behavior of three types of gold nanoparticles (obtained respectively by chemical synthesis, laser ablation in pure water and laser ablation in a citrate solution) modified with trans-zeatin, a plant growth regulator, in presence of glutathione. The reaction of ligand substitution of the adsorbed zeatin with glutathione is studied through surface enhanced Raman spectroscopy and is revealed to occur only when citrate-laser ablated gold nanoparticles are employed, making these particles potentially good candidates as vehicles of zeatin inside plant cells for future agricultural applications

Measuring the mixing efficiency in a simple model of stirring:some analytical results and a quantitative study via Frequency Map Analysis

We prove the existence of invariant curves for a $T$--periodic Hamiltonian system which models a fluid stirring in a cylindrical tank, when $T$ is small and the assigned stirring protocol is piecewise constant. Furthermore, using the Numerical Analysis of the Fundamental Frequency of Laskar, we investigate numerically the break down of invariant curves as $T$ increases and we give a quantitative estimate of the efficiency of the mixing.Comment: 10 figure