Quantum Interference in Spontaneous Decay of a Quantum Emitter Placed in a Dimer of Bismuth-Chalcogenide Microparticles

We investigate the phenomenon of quantum interference in spontaneous emission for a three-level V-type quantum emitter placed between two bismuth-chalcogenide (Bi2Te3, Bi2Se3) microspheres. In particular, we find that the degree of quantum interference can become as high as 0.994, a value which is attributed to the strong dependence of the spontaneous emission rate on the orientation of an atomic dipole relative to the surfaces of the microspheres, at the excitation frequencies of phonon-polariton states of the bismuth-chalcogenide microspheres (anisotropic Purcell effect). As a consequence of the high degree of quantum interference, we observe the occurrence of strong population trapping in the quantum emitter. To the best of our knowledge, the reported values of the degree of quantum interference are record values and are obtained for a relatively simple geometrical setup such as that of a microparticle dimer

Electrocardiographic Manifestations in three Psychiatric patients with Hypothermia – Case Report

Hypothermia occurs when the core body temperature falls below 35°C, which, in severe cases, can lead to electrocardiographic changes. Several conditions that occur in the psychiatric population increase the risk of hypothermia. This risk can be further increased by the use of several classes of medications such as antipsychotics, beta-adrenergic antagonists and benzodiazepines. We report on three psychiatric patients who were admitted for hypothermia and developed electrocardiographic manifestations (sinus bradycardia, QT prolongation and Osborn waves), which completely resolved after treatment

Prediction of Gold Nanoparticle and Microwave-Induced Hyperthermia Effects on Tumor Control via a Simulation Approach

Hyperthermia acts as a powerful adjuvant to radiation therapy and chemotherapy. Recent advances show that gold nanoparticles (Au-NPs) can mediate highly localized thermal effects upon interaction with laser radiation. The purpose of the present study was to investigate via in silico simulations the mechanisms of Au-NPs and microwave-induced hyperthermia, in correlation to predictions of tumor control (biological endpoints: tumor shrinkage and cell death) after hyperthermia treatment. We also study in detail the dependence of the size, shape and structure of the gold nanoparticles on their absorption efficiency, and provide general guidelines on how one could modify the absorption spectrum of the nanoparticles in order to meet the needs of specific applications. We calculated the hyperthermia effect using two types of Au-NPs and two types of spherical tumors (prostate and melanoma) with a radius of 3 mm. The plasmon peak for the 30 nm Si-core Au-coated NPs and the 20 nm Au-NPs was found at 590 nm and 540 nm, respectively. Considering the plasmon peaks and the distribution of NPs in the tumor tissue, the induced thermal profile was estimated for different intervals of time. Predictions of hyperthermic cell death were performed by adopting a three-state mathematical model, where “three-state„ includes (i) alive, (ii) vulnerable, and (iii) dead states of the cell, and it was coupled with a tumor growth model. Our proposed methodology and preliminary results could be considered as a proof-of-principle for the significance of simulating accurately the hyperthermia-based tumor control involving the immune system. We also propose a method for the optimization of treatment by overcoming thermoresistance by biological means and specifically through the targeting of the heat shock protein 90 (HSP90), which plays a critical role in the thermotolerance of cells and tissues

Gold nanoparticles, radiations and the immune system: Current insights into the physical mechanisms and the biological interactions of this new alliance towards cancer therapy

Considering both cancer's serious impact on public health and the side effects of cancer treatments, strategies towards targeted cancer therapy have lately gained considerable interest. Employment of gold nanoparticles (GNPs), in combination with ionizing and non-ionizing radiations, has been shown to improve the effect of radiation treatment significantly. GNPs, as high-Z particles, possess the ability to absorb ionizing radiation and enhance the deposited dose within the targeted tumors. Furthermore, they can convert non-ionizing radiation into heat, due to plasmon resonance, leading to hyperthermic damage to cancer cells. These observations, also supported by experimental evidence both in vitro and in vivo systems, reveal the capacity of GNPs to act as radiosensitizers for different types of radiation. In addition, they can be chemically modified to selectively target tumors, which renders them suitable for future cancer treatment therapies. Herein, a current review of the latest data on the physical properties of GNPs and their effects on GNP circulation time, biodistribution and clearance, as well as their interactions with plasma proteins and the immune system, is presented. Emphasis is also given with an in depth discussion on the underlying physical and biological mechanisms of radiosensitization. Furthermore, simulation data are provided on the use of GNPs in photothermal therapy upon non-ionizing laser irradiation treatment. Finally, the results obtained from the application of GNPs at clinical trials and pre-clinical experiments in vivo are reported