1,721,241 research outputs found
Hybrid Two Scales Mathematical Tools for ActiveParticles Modelling Complex Systems with Learning HidingDynamics
No full textThis paper deals with the derivation of hybrid mathematical structures to describe the behavior of large systems of active particles by ordinary differential equations with stochastic coefficients whose evolution is modelled by equations of the mathematical kinetic theory. A preliminary analysis shows how the above tools can be used to model complex systems of interest in applied sciences, with special attention to the immune competition
Qualitative Analysis of Second Order Models of Tumor-Immune System Competition
No full textThis paper deals with the qualitative analysis, existence of equilibria and asymptotic behavior of some second-order models of
the competition between tumor and immune cells. The background model belongs to d’Onofrio [A. d’Onofrio, A general framework
for modeling tumor–immune system competition and immunotherapy: Mathematical analysis and biomedical inferences, Physica
D 208 (2005) 220–235; A. d’Onofrio, Tumor–immune system interaction: Modelig the tumor-stimulated proliferation of effectors
and immunotherapy, Math. Models Methods Appl. Sci. 16 (2006) 1375–1401]. Various developments proposed in this paper are
focussed on the hiding–learning dynamics, followed by the qualitative analysis
Simple biophysical model of tumor evasion from immune system control
No full textThe competitive nonlinear interplay between a tumor and the host's immune system is not only very complex but is also time-changing. A fundamental aspect of this issue is the ability of the tumor to slowly carry out processes that gradually allow it to become less harmed and less susceptible to recognition by the immune system effectors. Here we propose a simple epigenetic escape mechanism that adaptively depends on the interactions per time unit between cells of the two systems. From a biological point of view, our model is based on the concept that a tumor cell that has survived an encounter with a cytotoxic T-lymphocyte (CTL) has an information gain that it transmits to the other cells of the neoplasm. The consequence of this information increase is a decrease in both the probabilities of being killed and of being recognized by a CTL. We show that the mathematical model of this mechanism is formally equal to an evolutionary imitation game dynamics. Numerical simulations of transitory phases complement the theoretical analysis. Implications of the interplay between the above mechanisms and the delivery of immunotherapies are also illustrated
Metamodeling the learning-hiding competition between tumours and immune system: a kinematic approach
No full textIndagini chimico-mineralogiche su ceramica a pasta grigia proveniente dalla Puglia centrale
No full textUno Studio Preliminare Afm con Risoluzione Molecolare sull'adsorbimento della Glucosio Ossidasi su Oro
No full textS. MARTINO AL CIMIN
On Systems of Active Particles Perturbed by Symmetric Bounded Noises: A Multiscale Kinetic Approach
Full text linkWe consider an ensemble of active particles, i.e., of agents endowed by internal variables u(t). Namely, we assume that the nonlinear dynamics of u is perturbed by realistic bounded symmetric stochastic perturbations acting nonlinearly or linearly. In the absence of birth, death and interactions of the agents (BDIA) the system evolution is ruled by a multidimensional Hypo-Elliptical Fokker–Plank Equation (HEFPE). In presence of nonlocal BDIA, the resulting family of models is thus a Partial Integro-differential Equation with hypo-elliptical terms. In the numerical simulations we focus on a simple case where the unperturbed dynamics of the agents is of logistic type and the bounded perturbations are of the Doering–Cai–Lin noise or the Arctan bounded noise. We then find the evolution and the steady state of the HEFPE. The steady state density is, in some cases, multimodal due to noise-induced transitions. Then we assume the steady state density as the initial condition for the full system evolution. Namely we modeled the vital dynamics of the agents as logistic nonlocal, as it depends on the whole size of the population. Our simulations suggest that both the steady states density and the total population size strongly depends on the type of bounded noise. Phenomena as transitions to bimodality and to asymmetry also occur
On a Mathematical Model of Immune Competition
Full text linkThis work deals with the qualitative analysis of a nonlinear integro-differential model of immune competition with special attention to the dynamics of tumor cells contrasted by the immune system. The analysis gives evidence of how initial conditions and parameters influence the asymptotic behavior of the solutions
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