Federico Papa

Federico Papa
Sapienza University of Rome | la sapienza · Department of Computer, Automatic and Management Engineering "Antonio Ruberti"

About

25
Publications
653
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110
Citations

Publications

Publications (25)
Article
We address a non-linear programming problem to find the optimal scheme of dose fractionation in cancer radiotherapy. Using the LQ model to represent the response to radiation of tumour and normal tissues, we formulate a constrained non-linear optimization problem in terms of the variables number and sizes of the dose fractions. Quadratic constraint...
Article
In the present paper we propose a simple time-varying ODE model to describe the evolution of HIV epidemic in Italy. The model considers a single population of susceptibles, without distinction of high-risk groups within the general population, and accounts for the presence of immigration and emigration, modelling their effects on both the general d...
Article
Full-text available
Insulin resistance is the common denominator of several diseases including type 2 diabetes and cancer, and investigating the mechanisms responsible for insulin signaling impairment is of primary importance. A mathematical model of the insulin signaling network (ISN) is proposed and used to investigate the dose-response curves of components of this...
Data
Model predictions for L6 myotubes. (A, B) Model prediction of IRS1nY (panel A) and IRS1nS (panel B) for cells in control medium at zero and 10 nM insulin in the absence of inhibitor (green), and in the presence of 50 nM rapamycin (yellow) and 500 nM PP242 (pink). (C, D) Model predictions as in (A) and (B), but for cells exposed to db/db medium. Pan...
Data
ISN response to the mTOR inhibitor AZD8055. (A) Relationship between the decrease of pS6K1 (Thr389) (squares) and that of λ1 at increasing concentrations of the drug. The fitting line has equation y = 1.10 x/(0.35·10-2+x), with y = pS6K1 (Thr389) and x = λ1. A similar function fits the relation between FoxO1cyt (triangles) and λ1. Data are normaliz...
Data
Supporting Information Text. Text S1: Summary of reactions within the insulin signaling network. Text S2: Kinetic and equilibrium equations. Text S3: Improved activation model of Akt and mTOR complexes. (DOCX)
Data
Expression of ISN model parameters in Eqs (1)–(16) of section Models in terms of the kinetic parameters of the equations in S1 File (Text S2). (PDF)
Data
Estimates of parameters of the cell population model in control and in cells exposed to 10, 100, and 1000 nM AZD8055. (PDF)
Data
Sensitivity analysis for the ISN model of L6 myotubes. The plot shows the sensitivities of protein concentrations to the estimated parameters of the model at the extracellular insulin concentration of 9.69 nM for control cells (upper panel) and cells in db/db medium (lower panel). (PDF)
Data
Experimental data of C2C12 myoblasts (not used in the parameter estimation) and model predictions. Data (mean ± SEM) in panels A and B are replotted from Ref [32] of main text. (A) Relative pAS160 (Thr642) concentration in control (black) and PTEN-suppressed (red) cells, together with the dose-response curves predicted by the model. The equation fo...
Data
Sensitivity analysis for the ISN model of C2C12 myocytes. The plot shows the sensitivities of protein concentrations to the estimated parameters of the model at the extracellular insulin concentration of 44.68 nM. (PDF)
Data
Parameters in Eqs (1)–(16) in Models estimated from data of C2C12 and L6 cells. (PDF)
Article
This work concerns the optimization of the dose fractionation for cancer radiotherapy schedules of the kind one fraction/day, five fractions/week, assuming a fixed overall treatment time. Constraints are set to limit the radiation damages to surrounding normal tissues, as well as the daily fraction size. The response to radiation of tumour and norm...
Article
We address the problem of defining a good trade off between reducing the cost of measurement and keeping the estimate accuracy within acceptable levels for continuous time linear system filtering problems. A measurement procedure which modifies the classical Kalman filter is proposed, allowing a sensible reduction of the measurement time intervals....
Technical Report
We report the analytical study of a constrained optimization problem which consists in fi�nding the minimal value of the largest entry of a vector d in R5, with constraints involving the entries sum and the squared entries sum. The solution of the problem studied in this paper provides the proof of a property needed to determine the admissible prot...
Article
Full-text available
We address the problem of finding the optimal radiotherapy fractionation scheme, representing the response to radiation of tumour and normal tissues by the LQ model including exponential repopulation and sublethal damage due to incomplete repair. We formulate the nonlinear programming problem of maximizing the overall tumour damage, while keeping t...
Article
Full-text available
In Bertuzzi et al. [1] we addressed the problem of finding the optimal radiotherapy fractionation scheme, representing the response to radiation of tumour and normal tissues by the LQ model including exponential repopulation and sublethal damage due to incomplete repair. We formulated the nonlinear programming problem of maximizing the overall tumo...
Article
With reference to a (discrete time) linear system filtering problem, we consider the problem of online deciding at which instant we actually measure and process the output values. We propose a convenient measurement policy, able to sensibly reduce the measurement cost, while keeping the estimate accuracy at satisfactory levels. By some probabilisti...
Article
We propose a spatially distributed continuous model for the spheroid response to radiation, in which the oxygen distribution is represented by means of a diffusion-consumption equation and the radiosensitivity parameters depend on the oxygen concentration. The induction of lethally damaged cells by a pulse of radiation, their death, and the degrada...
Article
Full-text available
Two spatially uniform models of tumour growth after a single instantaneous radiative treatment are presented in this paper. The two ordinary differential equations models presented may be obtained from two equivalent partial derivative equations models, by integration with respect to the radial distance. The main purpose of the paper is to study th...
Article
Full-text available
With reference to a (discrete time) linear system filtering problem, we consider the problem of on line deciding at which instant actually measure and process the output values. We propose a convenient measurement policy, able to sensibly reduce the measurement cost, while keeping the estimate accuracy at satisfactory levels. By some probabilistic...

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