Self-action effects in hyperbolic metamaterials based on gold nanorods.

Intensive studies of hyperbolic metamaterials (HMMs) are induced by unique optical properties of this type of artificial media associated with their hyperbolic dispersion. Special attention is attracted to the nonlinear optical response of HMMs, which reveals anomalous behavior in definite spectral regions. Third-order nonlinear optical self-action effects that are perspective for applications were analyzed numerically, whereas such experiments have not been performed up to now. In this work we study experimentally the effects of the nonlinear absorption and refraction in ordered arrays of gold nanorods in porous aluminum oxide. We demonstrate strong enhancement and sign reversal of these effects in the vicinity of the epsilon-near-zero spectral point due to the resonant light localization and transition from elliptical to hyperbolic dispersion regimes.

Second-harmonic generation spectroscopy in gold nanorod-based epsilon-near-zero metamaterials.

The interest in hyperbolic metamaterials is fueled by fascinating optical properties exhibited by this class of artificial media. Their optical features originate from hyperbolic dispersion emerging due to the shape anisotropy of the metal-dielectric composite. In this work, we study experimentally and numerically the second-harmonic generation (SHG) in ordered arrays of Au nanorods embedded in porous aluminum oxide. Strong increase of the SHG intensity in the vicinity of the epsilon-near-zero (ENZ) spectral point accompanied by dramatic phase modulation of the SHG wave is revealed. These effects are attributed to resonant enhancement of the electric field of the light wave and transition from the elliptical to hyperbolic dispersion law in hyperbolic metamaterials near the ENZ point.

[The assessment of prognosis of carotid endarterectomy by cliniсal-mathematical method].

We examined 127 patients with atherosclerotic stenosis of carotid arteries who underwent carotid endarterectomy (CEAE). In the most of patients (85%), CEAE slowed the progression of chronic cerebral ischemia leading to the stabilization or improvement of neurologic and/or neuropsychological status. The analysis of the data allowed to suggest a mathematical model for predicting the outcome of the surgery.

[The study of some mechanisms of injurious effects of low-frequency noises]. / Issledovanie nekotorykh mekhanizmov povrezhdaiushchikh éffektov nizkochastotnykh shumov.

Low-frequency noise has been shown to cause certain functional changes in the organism of laboratory animals that manifest in changes of the state of the regulatory systems and metabolic disturbances at cellular and subcellular levels. The obtained data support the hypothesis of the mechanism of injurious effect of this physical factor including two basically correlated ways, i.e. the central mechanism associated with overexcitation of the hypotalamohypophysis-adrenal system and mediating the homeostatic parameters of the body, and the local one which is determined by a direct effect of low-frequency noise on highly organized structure of membraneous and genetic apparatus of cells.