Publications by authors named "D'Onofrio A"

In this work, we generalize the Pugliese-Gandolfi Model [A. Pugliese and A. Gandolfi, Math Biosc, 214,73 (2008)] of interaction between an exponentially replicating pathogen and the immune system.

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'Rational' exemption to vaccination is due to a pseudo-rational comparison between the low risk of infection, and the perceived risk of side effects from the vaccine. Here we consider rational exemption in an SI model with information dependent vaccination where individuals use information on the disease's spread as their information set. Using suitable assumptions, we show the dynamic implications of the interaction between rational exemption, current and delayed information.

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By studying a recent biophysical model of tumor growth in the presence of the immune system, here we propose that the phenomenon of evasion of tumors from immune control at a temporal mesoscale might, in some cases, be due to random fluctuations in the levels of the immune system. Bounded noises are considered, but the Gaussian approach is also used for analytical reference. After showing that in the case of bounded noises there may be multiple attractors in the space of probability densities, we numerically show that the velocity of convergence toward asymptotic density is very slow and that a transitory analysis is needed.

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The majority of bacterial species do not grow on synthetic media. Many non-growers require growth factors from other bacteria, but the nature of these compounds is largely unknown. We show here that previously uncultured isolates from marine sediment biofilm grow on a Petri dish in the presence of cultured organisms from the same environment.

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We show the potentiality of coupling together different compound-specific isotopic analyses in a laboratory experiment, where (13)C-depleted leaf litter was incubated on a (13)C-enriched soil. The aim of our study was to identify the soil compounds where the C derived from three different litter species is retained. Three (13)C-depleted leaf litter (Liquidambar styraciflua L.

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For infections for which the perceived risk of serious disease is steadily low, the perceived risk of suffering some vaccine side effects might become the driving force of the vaccine demand. We investigate the dynamics of SIR infections in homogeneously mixing populations where the vaccine uptake is a decreasing function of the current (or past) incidence, or prevalence, of vaccine side effects. We define an appropriate model where vaccine side-effects are modelled as functions of the age since vaccination.

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In this work we propose to model chemotherapy taking into account the mutual interaction between tumour growth and the development of tumour vasculature. By adopting a simple model for this interaction, and assuming that the efficacy of a drug can be modulated by the vessel density, we study the constant continuous therapy, the periodic bolus-based therapy, and combined therapy in which a chemotherapic drug is associated with an anti-angiogenic agent. The model allows to represent the vessel-disrupting activity of some standard chemotherapic drugs, and shows, in the case of constant continuous drug administration, the possibility of multiple stable equilibria.

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The aim of this study is to compare outcomes of patients undergoing surgical ventricular reconstruction (SVR) with normothermic cardiopulmonary bypass (CPB) and beating heart or hypothermic CPB and cardioplegic arrest. Between 2001 and 2008, 588 patients underwent SVR. A propensity score matching was performed and 91 matched pairs were created: group 1 (G1) operated with normothermic CPB and beating-heart technique, and group 2 (G2) operated with hypothermic CPB and cardioplegic arrest.

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Rupture of cardiac valves as a consequence of nonpenetrating cardiac trauma is an uncommon phenomenon. We report the case of a 24-year-old patient with a "two-stage" traumatic rupture of the anterolateral papillary muscle of the mitral valve, after a blunt chest trauma, who successfully underwent emergency mitral valve replacement.

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A threat for vaccination policies might be the onset of "rational" exemption, i.e. the family's decision not to vaccinate children after a seemingly rational comparison between the perceived risk of infection and the perceived risk of vaccine side effects.

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A mathematical model for the scheduling of angiogenic inhibitors in combination with a chemotherapeutic agent is formulated. Conditions are given that allow tumor eradication under constant infusion therapies. Then the optimal scheduling of a vessel disruptive agent in combination with a cytotoxic drug is considered as an optimal control problem.

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The 3He(alpha,gamma)7Be reaction presently represents the largest nuclear uncertainty in the predicted solar neutrino flux and has important implications on the big bang nucleosynthesis, i.e., the production of primordial 7Li.

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(137)Cs and (60)Co, two of the radionuclides more representative of discharges from nuclear facilities, are of interest for radiological protections because of their great mobility in biosphere and affinity with biological systems. The aim of the present work is the investigation of the possible influence of the vertical distribution of (137)Cs and (60)Co in soil upon their uptake by lettuce as function of plant's growth. An experiment ad hoc has been carried out in field conditions.

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Objectives: The administration schedule appears to be a particularly relevant factor in determining the effectiveness of an antiangiogenic drug. A better quantitative knowledge of the interactions between tumour growth and the development of its vasculature could help to design effective therapies.

Material And Methods: Biological and clinical inferences were derived from the analysis of a mathematical model proposed by Hahnfeldt et al.

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We analyze the effect of porosity in a porous medium on hydrodynamic instabilities in reaction-diffusion fronts. We use an experimental device to create an effective two-dimensional porous medium which is vertically orientated. In this system the molecular diffusion coefficients and the acid autocatalysis of the chlorite-tetrathionate reaction satisfy the appropriate conditions to produce a chemical front that advances through the cell leading to the products overlaying the reactants.

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In this paper we propose a class of models that describe the mutual interaction between tumour growth and the development of tumour vasculature and that generalize existing models. The study is mainly focused on the effect of a therapy that induces tumour vessel loss (anti-angiogenic therapy), with the aim of finding conditions that asymptotically guarantee the eradication of the disease under constant infusion or periodic administration of the drug. Furthermore, if tumour and/or vessel dynamics exhibit time delays, we derive conditions for the existence of Hopf bifurcations.

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It is well known that behavioral changes in contact patterns may significantly affect the spread of an epidemic outbreak. Here we focus on simple endemic models for recurrent epidemics, by modelling the social contact rate as a function of the available information on the present and the past disease prevalence. We show that social behavior change alone may trigger sustained oscillations.

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A challenge to disease control in modern societies is the spread of rational exemption to vaccination as a consequence of the rational comparison between the steadily declining risk of infection and the risk of side effects from the vaccine. Here, we consider rational exemption in an susceptible-infectious-removed (SIR) model with information-dependent vaccination where individuals use information on the disease's mortality as their information set. Using suitable assumptions on the dynamics of the population, we show the dynamic implications of the interaction between rational exemption, current and delayed information and the risk of death by the disease.

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In recent years, numerous studies focusing on the role of sex steroid hormones on neuropsychological functions have been reported. The influence of estrogens on cognition can be explained by the widespread presence of estrogen receptors (ERs) in limbic and cortical areas, and the modulator role of estrogens on numerous neurotransmitter systems. There is a great deal of evidence suggesting that estrogen can enhance memory processes and improve performance in working memory (WM) tasks, including face-tasks, delayed matching-to-sample (DMTS) and delayed non-matching-to-sample (DNMTS).

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The creation of a fistula between the subclavian artery and the oesophagus is extremely rare. All the reported cases of subclavian oesophagus-arterial fistulae have been described either in aberrant subclavian arteries or as caused by foreign bodies in the oesophagus. In this article, a case of fistulous communication between an aberrant right subclavian and the oesophagus managed with the positioning of endovascular prosthesis is presented.

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We study the global behavior of a non-linear susceptible-infectious-removed (SIR)-like epidemic model with a non-bilinear feedback mechanism, which describes the influence of information, and of information-related delays, on a vaccination campaign. We upgrade the stability analysis performed in d'Onofrio et al. [A.

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Physiological hormonal fluctuations during the menstrual cycle, postpartum, and menopause have been implicated in the modulation of mood, cognition, and affective disorders. Taking into account that women's performance in memory tasks can also fluctuate with circulating hormones levels across the menstrual cycle, the cognitive performance in a working memory task for emotional facial expressions, using the six basic emotions as stimuli in the delayed matching-to-sample, was evaluated in young women in different phases of the menstrual cycle. Our findings suggest that high levels of estradiol in the follicular phase could have a negative effect on delayed matching-to-sample working memory task, using stimuli with emotional valence.

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The aim of the study is to verify the presence of the carcinogenic risk for teachers, technical assistants and students in 96 secondary schools, providing suggestions for its assessment. Since the analysis of the national and international scientific literature does not reveal data on the evaluation of the carcinogenic risk nor in schools nor in similar environments, the authors gave importance to the preliminary phase of the risk assessment that is to say the inspections aimed to detect the possible presence of risk agents and to identify the possible exposed subjects. The evaluation of the exposition through the execution of environmental and biological monitoring has to be performed, according to the authors opinion, only after this indispensable preliminary phase.

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