scholarly journals Nanoshells for photothermal therapy: a Monte-Carlo based numerical study of their design tolerance

2011 ◽  
Vol 2 (6) ◽  
pp. 1584 ◽  
Author(s):  
Thomas Grosges ◽  
Dominique Barchiesi ◽  
Sameh Kessentini ◽  
Gérard Gréhan ◽  
Marc Lamy de la Chapelle
Keyword(s):  
Monte Carlo ◽  
Photothermal Therapy ◽  
Numerical Study ◽  
Design Tolerance

scholarly journals Numerical Study on Factors Affecting the Induction of Apoptotic Temperatures of Tumor in the Multi-Layer Skin Structure Using Monte Carlo Method

2021 ◽  
Vol 11 (3) ◽  
pp. 1103
Author(s):  
Donghyuk Kim ◽  
Sukkyung Kang ◽  
Hyunjung Kim
Keyword(s):  
Monte Carlo ◽  
Numerical Analysis ◽  
Monte Carlo Method ◽  
Skin Cancer ◽  
Photothermal Therapy ◽  
Volume Fraction ◽  
Numerical Study ◽  
Secondary Infection ◽  
Reticular Dermis ◽  
Therapy Effect

The incidence of skin cancer is increasing with the recent increase in UV exposure. The treatment of skin cancer generally proceeds through an excision of the tumor area, which causes bleeding into the affected area and surrounding tissues, and there is a possibility that secondary infection may occur. Photothermal therapy is drawing attention as an alternative treatment to overcome this limitation. In this study, a numerical analysis was performed on skin cancer tumors located between the reticular dermis and the skin surface by applying the Monte Carlo method. The numerical analysis derives a quantitative correlation using an effective apoptosis ratio with respect to the intensity of the laser that produces the optimal photothermal therapy effect and the volume fraction of gold nanorods (GNRs) injected into a tumor. Through this study, it is confirmed that the optimal treatment effect exists for the depth and length of the various tumors, the intensity of the laser, and the volume fraction of GNRs to minimize the thermal damage to the surrounding normal tissues while maximizing the apoptosis in the tumor. It is expected that it can be used as an optimal condition for better treatment while performing photothermal therapy in the future.

A numerical study of the sedimentation of fibre suspensions

1998 ◽  
Vol 376 ◽  
pp. 149-182 ◽  
Author(s):  
MICHAEL B. MACKAPLOW ◽  
ERIC S. G. SHAQFEH
Keyword(s):  
Monte Carlo ◽  
Steady State ◽  
Monte Carlo Simulations ◽  
Numerical Study ◽  
Point Particle ◽  
Hydrodynamic Interactions ◽  
Dynamic Simulations ◽  
Slender Body Theory ◽  
Fibre Suspensions ◽  
The Mean

The sedimentation of fibre suspensions at low Reynolds number is studied using two different, but complementary, numerical simulation methods: (1) Monte Carlo simulations, which consider interparticle hydrodynamic interactions at all orders within the slender-body theory approximation (Mackaplow & Shaqfeh 1996), and (ii) dynamic simulations, which consider point–particle interactions and are accurate for suspension concentrations of nl3=1, where n and l are the number density and characteristic half-length of the fibres, respectively. For homogeneous, isotropic suspensions, the Monte Carlo simulations show that the hindrance of the mean sedimentation speed is linear in particle concentration up to at least nl3=7. The speed is well predicted by a new dilute theory that includes the effect of two-body interactions. Our dynamic simulations of dilute suspensions, however, show that interfibre hydrodynamic interactions cause the spatial and orientational distributions to become inhomogeneous and anisotropic. Most of the fibres migrate into narrow streamers aligned in the direction of gravity. This drives a downward convective flow within the streamers which serves to increase the mean fibre sedimentation speed. A steady-state orientation distribution develops which strongly favours fibre alignment with gravity. Although the distribution reaches a steady state, individual fibres continue to rotate in a manner that can be qualitatively described as a flipping between the two orientations aligned with gravity. The simulation results are in good agreement with published experimental data.

scholarly journals Optimization of Nonspherical Gold Nanoparticles for Photothermal Therapy

2019 ◽  
Vol 9 (20) ◽  
pp. 4300
Author(s):  
Paerhatijiang Tuersun ◽  
Xiayiding Yakupu ◽  
Xiang’e Han ◽  
Yingzeng Yin
Keyword(s):  
Gold Nanoparticles ◽  
Refractive Index ◽  
Photothermal Therapy ◽  
Therapeutic Agents ◽  
Tissue Type ◽  
Excitation Wavelength ◽  
Objective Functions ◽  
Design Tolerance ◽  
T Matrix ◽  
Selection Of

Previous investigations devoted to the optimization of nonspherical gold nanoparticles for photothermal therapy (PTT) encountered two issues, namely, the appropriate selection of objective functions and the processing of particle random orientations. In this study, these issues were resolved, and accurate optimization results were obtained for the three typical nonspherical gold nanoparticles (nanospheroid, nanocylinder, and nanorod) by using the T-matrix method. The dependence of the optimization results on the excitation wavelength and the refractive index of tissue was investigated. Regardless of the excitation wavelength and tissue type, gold nanospheroids were found to be the most effective therapeutic agents for PTT. The light absorption ability of optimized nanoparticles could be enhanced by using a laser with a longer wavelength. Finally, the design tolerance for the different sizes of nanoparticles was provided.

scholarly journals APPLICATION OF STATISTICAL CRITERIA TO OPTIMALITY TESTING IN STOCHASTIC PROGRAMMING

2006 ◽  
Vol 12 (4) ◽  
pp. 314-320 ◽  
Author(s):  
Leonidas Sakalauskas ◽  
Kestutis Žilinskas
Keyword(s):  
Monte Carlo ◽  
Numerical Study ◽  
Finite Sequence ◽  
Monte Carlo Sampling ◽  
Adaptive Method ◽  
Linear Rate ◽  
Ratio Approach ◽  
Linear Problems ◽  
Carlo Estimate ◽  
Statistical Criteria

In this paper the stochastic adaptive method has been developed to solve stochastic linear problems by a finite sequence of Monte‐Carlo sampling estimators. The method is grounded on adaptive regulation of the size of Monte‐Carlo samples and the statistical termination procedure, taking into consideration the statistical modeling error. Our approach distinguishes itself by treatment of the accuracy of the solution in a statistical manner, testing the hypothesis of optimality according to statistical criteria, and estimating confidence intervals of the objective and constraint functions. The adjustment of sample size, when it is taken inversely proportional to the square of the norm of the Monte‐Carlo estimate of the gradient, guarantees the convergence a. s. at a linear rate. We examine four estimators for stochastic gradient: by the differentiation of the integral with respect to x, the finite difference approach, the Simulated Perturbation Stochastic Approximation approach, the Likelihood Ratio approach. The numerical study and examples in practice corroborate the theoretical conclusions and show that the procedures developed make it possible to solve stochastic problems with a sufficient agreeable accuracy by means of the acceptable amount of computations.

scholarly journals Monte Carlo modelling of Th-Pb fuel assembly with californium neutron source

Nukleonika ◽  
2018 ◽  
Vol 63 (3) ◽  
pp. 87-91
Author(s):  
Mikołaj Oettingen ◽  
Przemysław Stanisz
Keyword(s):  
Stainless Steel ◽  
Monte Carlo ◽  
Neutron Source ◽  
Nuclear Energy ◽  
Numerical Study ◽  
Experimental Measurements ◽  
Hexagonal Array ◽  
Fuel Rods ◽  
Numerical Reconstruction ◽  
Continuous Energy

Abstract This paper describes the methodology developed for the numerical reconstruction and modelling of the thorium-lead (Th-Pb) assembly available at the Department of Nuclear Energy, Faculty of Energy and Fuels, AGH University, Krakow, Poland. This numerical study is the first step towards integral irradiation experiments in the Th-Pb environment. The continuous-energy Monte Carlo burnup (MCB) code available on supercomputer Prometheus of ACK Cyfronet AGH was applied for numerical modelling. The assembly consists of a hexagonal array of ThO2 fuel rods and metallic Pb rods. The design allows for different arrangements of the rods for various types of irradiations and experimental measurements. The intensity of the fresh neutron source intended for integral experiments is about 108 n/s, which corresponds to the mass of about 43 μg 252Cf. The source was modelled in the form of Cf2O3-Pd cermet wire embedded in two stainless steel capsules.

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