Different regimes of the Purcell effect in disordered photonic crystals.

We demonstrate that disorder in photonic crystals could lead to pronounced modification of spontaneous emission rate in the frequency region corresponding to the photonic band gap (PBG). Depending on the amount of disorder, two different regimes of the Purcell effect occurs. We provide statistical analysis of Purcell coefficient on the frequency of the emitter and its position within the sample. For the moderate disorder, an enhancement of spontaneous emission occurs at the edge of PBG due to the modification of properties of the edge state. This effect is responsible for recently observed mirrorless lasing in photonic crystals at the edge of PBG. When the level of disorder increases, the spontaneous emission rate enhances within the PBG due to the appearance of the high quality factor states. This effect is likely responsible for a superlinear dependence of emissions on pumping observed in synthetic opals.

Enhancement of spontaneous emission in Tamm plasmon structures.

It was theoretically and experimentally demonstrated that in metal/semiconductor Tamm plasmon structures the probability of spontaneous emission can be increased despite losses in metal, and theoretical analysis of experimental results suggested that the enhancement could be as high as one order of magnitude. Tamm plasmon structure with quantum dots has been fabricated and the emission pattern has been measured. Electromagnetic modes of the structure have been analyzed and modification of spontaneous emission rates has been calculated showing a good agreement with experimentally observed emission pattern.

Super-radiant mode in InAs-monolayer-based Bragg structures.

We report direct experimental evidence of the collective super-radiant mode in Bragg structure containing 60 InAs monolayer-based quantum wells (QWs) periodically arranged in GaAs matrix. Time-resolved photoluminescence measurements reveal an appearance of the additional super-radiant mode, originated from coherent collective interaction of QWs. This mode demonstrates a super-linear dependence of the intensity and radiative decay rate on the excitation power. The super-radiant mode is not manifested in the case if only a small number of QWs is excited.

Single and double bosonic stimulation of THz emission in polaritonic systems.

The influence of the surrounding cavity on the efficiency of different types of polaritonic emitters of THz radiation has been analysed. It is demonstrated that THz lasing threshold in realistic structures cannot be achieved without a THz cavity, due to destruction of polaritons via excitonic Mott transition. Even modest values of cavity quality factor (not exceeding 50) provide significant quantum efficiency.

[To the role of computed tomography in the algorithm of diagnosis of lung cancer]. / K voprosu o roli komp'iuternoi tomografii v algoritme diagnostiki raka legkogo.

The paper summarizes the results of examination of 100 patients with malignant tumors of the lung. The results of X-ray study, linear tomography, and computed tomography (CT) used in the examination of patients with lung cancer were compared by using as an indicator the following parameters: to make diagnosis of lung cancer, to reveal mediastinal intergrowths, to detect enlarged lymph nodes, pulmonary metastases, and pleural lesions, to obtain information on tumor spread into the chest, to reveal growths into the vascular walls. To evaluate the efficiency of the techniques in solving the above diagnostic tasks, a statistical analysis including the estimation of their accuracy, specificity, and sensitivity was made. Recommendations for examination of patients with lung cancer were drawn up for therapeutic institutions of different types.

Non-canonical functions of aminoacyl-tRNA synthetases.

The basic function of aminoacyl-tRNA synthetases (aaRSs) is an activation of the amino acids and their transfer to specific RNAs. In addition to this key role in protein biosynthesis, the enzymes of this group participate in other cell processes. aaRSs regulate the expression of some genes, not only their own. The regulation is carried out on the level of transcription, processing of mRNA, and translation. They catalyze the synthesis of dinucleoside oligophosphates and thus indirectly influence many other cell functions. Tyrosyl-tRNA synthetase was shown to have cytokine activities. Some aaRSs interact specifically with other proteins. Thus, aminoacyl-tRNA synthetases are involved in the regulation of the multiple processes of living cells. In this review we summarize the available data on unusual activities of aaRSs.

Phenylalanyl-tRNA synthetase interacts with DNA: studies on activity using deoxyribooligonucleotides.

Phenylalanyl-tRNA synthetase from Thermus thermophilus complexes with short (up to 30 nucleotide length) single-stranded DNA fragments more efficiently than with double-stranded fragments. The complexing between DNA and the protein significantly increases with deoxyribooligonucleotide longer than 20 nucleotides. Using affinity labeling, the binding site of DNA was located near the interface of the alpha- and beta-subunits. The binding sites of DNA and tRNAPhe do not overlap. Phenylalanyl-tRNA synthetase from E. coli also binds DNA.