Anomalous infrared conical emission during ordered multifilamentation in gases.

We demonstrate that amplitude modulation of a high-peak-power femtosecond laser pulse allows to change fundamentally the frequency-angular structure (FAS) of the supercontinuum formed during the filamentation in both molecular and atomic gases. Particularly, modulation with a 4-hole mask forms an inverted pattern of conical emission (CE) with its predominance in the Stokes wing of the pulse spectrum. We explain this phenomenon as a joint effect of self-phase modulation and temporal pulse splitting of interfering beamlets formed by the modulating mask.

Case presentation of acute ischemia induced ST-depression masking Brugada syndrome ECG pattern in a relatively young patient.

ECG in Brugada syndrome (BrS) is characterized by a ST-segment elevation in the right precordial leads. Overlap between ST-segment changes in BrS and ischemia may lead to diagnostic challenges. We report a case of a male patient presented with recurrent chest pain episodes and ST elevation in the right precordial leads consistent with Brugada ECG pattern type 1 and was clinically diagnosed with BrS at the age of 30 years.

Robust multifilament arrays in air by Dammann grating.

We compare transverse structure evolution and energy deposition into the medium within focused multifilament arrays created using two different types of diffraction optical elements (DOEs): TEM phase plate and a Dammann grating. We show that the employment of the Dammann grating provides a robust way to create regular multifilament arrays, which is far less dependent on laser beam quality than one using the phase plate.

Transient optical non-linearity in p-Si induced by a few cycle extreme THz field.

We study the impact of a few cycle extreme terahertz (THz) radiation (the field strength E ∼1-15 MV/cm is well above the DC-field breakdown threshold) on a p-doped Si wafer. Pump-probe measurements of the second harmonic of a weak infrared probe were done at different THz field strengths. The second harmonic yield has an unusual temporal behavior and does not follow the common instantaneous response, ∝TH2.

Postfilament supercontinuum on 100 m path in air.

Pulses at 744 nm with 90 fs duration, 6 mJ energy, and a weakly divergent wavefront propagate for more than 100 m and generate a filament followed by an unprecedently long high intensity (≥1/) light channel. Over a 20 m long sub-section of this channel, the pulse energy is transferred continuously to the infrared wing, forming spectral humps that extend up to 850 nm. From 3D+time carrier-resolved simulations of 100 m pulse propagation, we show that spectral humps indicate the formation of a train of femtosecond pulses appearing at a predictable position in the propagation path.

Hybrid stimulated Raman scattering-two-plasmon decay instability and 3/2 harmonic in steep-gradient femtosecond plasmas.

We numerically study interaction of a very intense (I∼10^{17} to 5×10^{19}W/cm^{2}) femtosecond obliquely incident p-polarized laser pulse with a steep-gradient (L∼λ) plasma, i.e., within the conditions typical for modern experiments.

Size-Dependent Bioactivity of Silver Nanoparticles: Antibacterial Properties, Influence on Copper Status in Mice, and Whole-Body Turnover.

Purpose: The ability of silver nanoparticles (AgNPs) of different sizes to influence copper metabolism in mice is assessed.

Materials And Methods: AgNPs with diameters of 10, 20, and 75 nm were fabricated through a chemical reduction of silver nitrate and characterized by UV/Vis spectrometry, transmission and scanning electronic microscopy, and laser diffractometry. To test their bioactivity, cells, cultured A549 cells, and C57Bl/6 mice were used.

Modeling and Estimation of Temporal Episode Patterns in Paroxysmal Atrial Fibrillation.

Objective: The present study proposes a model-based, statistical approach to characterizing episode patterns in paroxysmal atrial fibrillation (AF). Thanks to the rapid advancement of noninvasive monitoring technology, the proposed approach should become increasingly relevant in clinical practice.

Methods: History-dependent point process modeling is employed to characterize AF episode patterns, using a novel alternating, bivariate Hawkes self-exciting model.

State-Resolved Dissociation and Exchange Reactions in CO Flows.

State-resolved chemical reactions in CO are studied by taking into account excitation of all vibrational modes and preferential reaction mechanisms. The effect of several parameters on the reaction rate coefficients is discussed; it is shown that the nonequilibrium factor in the expression for the rate coefficients of exchange reactions is much less sensitive to the number of accounted vibrational states and model parameters than that of dissociation. On the other hand, the choice of thermal equilibrium Arrhenius law parameters is crucial for the correct prediction of rate coefficients for both reactions.

Observation of crossover from intraband to interband nonlinear terahertz optics.

In this Letter, we investigate the nonlinear effects of extremely intense few-cycle terahertz (THz) pulses (generated from the organic crystal 4-NN, NN-dimethylamino-44-NN-methyl-stilbazolium 2, 4, 6 trimethylbenzenesulfonate, with peak electrical fields of a few MV/cm) on the carrier dynamics in n-doped semiconductor thin film InGaAs. By performing open-aperture Z-scan measurements and recording the transmitted THz energy through semiconductor sample, we observed a strong THz absorption bleaching effect at high fields, followed by an absorption enhancement at even higher fields. We attribute our observations to a crossover from pure intraband carrier dynamics to an interplay between intraband carrier heating and interband carrier generations.

Ring and unimodal angular-frequency distribution of THz emission from two-color femtosecond plasma spark.

We study angular and frequency-angular distributions of the terahertz (THz) emission of the low-frequency region (0.3-3 THz) from a two-color femtosecond plasma spark experimentally and in three-dimensional numerical simulations. We investigate the dependence of the angular shapes of the THz radiation on focusing conditions and pulse durations by using two laser facilities (pulse durations 35 and 150 fs) for different focusing geometries.

Polarization control of terahertz radiation from two-color femtosecond gas breakdown plasma.

We individually control polarizations of 800 and 400 nm beams, which form a two-color femtosecond plasma filament in air irradiating a linear-to-elliptical THz signal. We detected a threshold-like appearance of THz ellipticity at the angle of ∼85° between the fundamental and second-harmonic field polarization directions. The simulations confirm the abrupt change of THz polarization and reveal that the weak ellipticity of the second harmonic is sufficient to generate essentially elliptical THz radiation.

Symmetry Breaking and Strong Persistent Plasma Currents via Resonant Destabilization of Atoms.

The ionization rate of an atom in a strong optical field can be resonantly enhanced by the presence of long-living atomic levels (so-called Freeman resonances). This process is most prominent in the multiphoton ionization regime, meaning that the ionization event takes many optical cycles. Nevertheless, here, we show that these resonances can lead to rapid subcycle-scale plasma buildup at the resonant values of the intensity in the pump pulse.

Giant self-induced transparency of intense few-cycle terahertz pulses in n-doped silicon.

The results of high-field terahertz transmission experiments on n-doped silicon (carrier concentration of 8.7×10  cm) are presented. We use terahertz pulses with electric field strengths up to 3.

Fifteen meter long uninterrupted filaments from sub-terawatt ultraviolet pulse in air.

A technique is presented to create uninterrupted long ultraviolet filaments in air using appropriately structured transmission mesh. The mesh with different cell sizes was inserted into 10-cm parallel beam of 0.2-J, 248-nm, and 870-fs pulse propagating along ~100-m corridor.

[Clinical and morphological parallels in the validation of surgical treatment of nephrotuberculosi].

Aim: To Study clinical and morphological variants of kidney tuberculosis (KTB), for grounding a tactics of surgical treatment.

Materials And Methods: There were 107 examined patients (patients with cavitary lesions of kidneys: cavernous and multi-cavernous), operated in different phases of KTB. There were 56 men (52,3%) and women - 51(47,7%).

An improved model of homogeneous nucleation for high supersaturation conditions: aluminum vapor.

A novel model of stationary nucleation, treating the thermodynamic functions of small clusters, has been built. The model is validated against the experimental data on the nucleation rate of water vapor obtained in a broad range of supersaturation values (S = 10-120), and, at high supersaturation values, it reproduces the experimental data much better than the traditional classical nucleation model. A comprehensive analysis of the nucleation of aluminum vapor with the usage of developed stationary and non-stationary nucleation models has been performed.

[Relapsing polychondritis].

Relapsing polychondritis (RP) is a systemic inflammatory condition leading to irreversible structural changes in cartilaginous tissue as a result of generalized proteoglycane decomposition. Auricular and nasal cartilage is usually the first to be affected at the onset of the disease which leads to episcleritis. At the later stages, the larynx and trachea become involved, vasculitis develops affecting the organs of hearing, coronary arteries, kidneys, meninges, and other organs.

[Pace of pulmonary function deterioration in patients with occupational bronchial diseases: influence of various factors].

Prospective cohort study covered 348 workers of dust-related occupations with verified occupational bronchial diseases. The authors studied dependence between industrial aerosol levels at workplace, smoking status and pace of pulmonary function decrease in individuals with chronic bronchitis and COLD. Conclusion is that totality of occupational bronchial diseases patients is uneven and differs in course and clinical and functional parameters.

[Characteristics of rat ceruloplasmin from the serum of animals, which received salts of silver with food].

Abiogenic Ag(I) ions have electronic structure, similar to Cu(I) ions and can compete with Cu(I) for binding sites of proteins which transport copper from extracellular media to sites of cuproenzyme formation in the cell. Rodents receiving Ag-salts with food develop extracellular deficiency of copper associated with ceruloplasmin (Cp, the major copper-transporting protein in blood serum of vertebrates). The present work focuses on the studies of biochemical and physicochemical properties of Cp, obtained from blood serum of rats, which received AgCl with food for 4 weeks (Ag-rats).

Polarization rotation due to femtosecond filamentation in an atomic gas.

The linear-to-elliptical transformation of a 400 nm femtosecond-probe pulse in the birefringent filament in argon of an 800 nm linearly polarized femtosecond-pump pulse is studied numerically and experimentally. The rotation of the probe elliptical polarization is the largest in the high-intensity filament core. With propagation, the rotated radiation diffracts outward by the pump-produced plasma.

Four-wave parametric conversion of femtosecond laser pulse in a filament induced in a solid target.

Nonlinear interaction of two femtosecond laser pulses in a filament, induced by one of them inside a fused silica plate, leads to generation of the new spectral components. These spectral components reach hundreds of nanometers bandwidth. Their spatial and spectral properties can be explained by four-wave parametric coupling in the filament.

[Dynamics of the formation of secondary reproductive structures in Streptomyces zone-forming colonies as determined from confocal microscopy data].

The dynamics of the formation of secondary structures on the colony surface, so-called air mycelium concentric rings, was investigated by confocal microscopy and using Streptomyces zone-forming colonies as a model of a self-organizing system. The occurrence of luminescence in reproductive structures was registered, whereas in vegetative structures it was almost completely absent. It was shown that secondary reproductive structures begin to form within the thickness of substratum mycelium as branches or as an apical extension of vegetative gyphes, followed by the formation of numerous secondary branches filled with protospores.