Towards Optimal Thermal Distribution in Magnetic Hyperthermia

Abstract

A linear combination of spherically symmetric heat sources is shown to provide optimal stationary thermal distribution in magnetic hyperthermia. Furthermore, such spatial location of heat sources produces suitable temperature distribution in biological medium even for assemblies of magnetic nanoparticles with a moderate value of specific absorption rate (SAR), of the order of 100 - 150 W/g. We also demonstrate the advantage of using assemblies of magnetic nanocapsules consisting of metallic iron nanoparticles covered with non magnetic shells of sufficient thickness in magnetic hyperthermia. Based on numerical simulation we optimize the size and geometric structure of biocompatible capsules in order to minimize the influence of strong magneto-dipole interaction between closely spaced nanoparticles. It is shown that assembly of capsules can provide sufficiently high SAR values of the order of 250 - 400 W/g at moderate amplitudes H0·= 50 - 100 Oe and frequencies f = 100 - 200 kHz of alternating magnetic field, being appropriate for application in clinics.

Electronic Modulation of Near-Field Radiative Transfer in Graphene Field Effect Heterostructures

“…We apply a standard fluctuational electrodynamics formalism − to assess the potential for this sample configuration to modulate near-field radiative flow. In Figure c, we present calculations of the spectral thermal conductance, defined as h (ω) = ∂ Q (ω)/∂ T , where Q is the radiative heat flux, for our device at T = 300 K at various gap distances and Fermi levels.…”

Dielectric Properties of Nanoconfined Water from Ab Initio Thermopotentiostat Molecular Dynamics

“…In order to recover ergodicity, the introduction of Nosé–Hoover chains was proposed, 27 however, at the cost of additional numerical parameters, and required extra tuning. In order to lift these requirements and enable a straightforward implementation of the potentiostating process into any simulation package, we were recently inspired by the MTP 6 and the Maxwell-Langevin equations of fluctuation electrodynamics 28 to introduce a stochastic canonical thermopotentiostat algorithm. 29 …”