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This paper presents a new concept for studying the spatio-temporal modes of laser generation in which several time scales coexist in the emission (one of which is related to the resonator round-trip time). The essence of the concept is that the time dependence of the intensity is investigated in two dimensions, one of which corresponds to the evolution over sequential resonator round-trips. It is shown that fiber lasers of various types, e.g., quasicontinuous lasers and passive and active mode locked pulsed lasers, has a diversity of spatio-temporal generation modes. The possibility of experimental detection of localized structures, including solitons, in fiber laser radiation is demonstrated. The prospects of the proposed approach are discussed.

A method of layer-by-layer heterodyne analysis of volume optical media is described. The results of theoretical evaluation, computer modeling, and experimental investigation of the dependence of the maximum speed of analysis of the parameters of the optical circuit and medium are given. The effect of the analysis speed on the resolution of the method for the thickness of the optical medium and on the nature of the dependence of the output signal on the depth of the studied layer is evaluated. A method for increasing the maximum scanning speed is proposed. Results are confirmed experimentally.

The asymmetric unit of the title compound C₁₄H₁₂BrN (systematic name (E-N-(4-bromophenyl)-1-(p-tolyl)methanimine) contains one half-molecule: a crystallographic center of inversion is located at the midpoint of the bridging N=C bond. The central HC=N unit makes dihedral angles of 15.7(3)° and 15.2(4)° with bromobenzene and methylbenzene ring systems, respectively. The C and N atoms of the HC=N central unit are disordered over two sites in a 50:50 ratio. The Br atom of the 4-bromoaniline ring and the methyl atom of the 4-methylbenzilidene ring systems are also 50 % disordered. In the crystal, molecules are linked by C-H⋯π interactions forming slabs parallel to the bc plane. The atomic coordinates are not available for the previously reported crystal structure of the title compound: CSD refcode MBZCLE. The reported R factor of 0.103 for the analysis in the space group P2₁/a is much higher than in the present analysis, which gives 0.033 in the space group P2₁/c.

Based on the information from the Cambridge Structural Database, 28 crystalline homomolecular structures of a,w-diols are analyzed (five of them at two temperature). Two variants of violation of the A. I. Kitaigorodsky “centrosymmetric rule” are found: 1) approximately centrosymmetric molecules do not take positions in the centers of inversion, which are present in space groups; 2) the compound forms two polymorphs, one of which obeys the rule and in another the molecules have a substantially non-centrosymmetric conformation. It is shown that the molecular coordination number found from the calculation of distances combines the molecules whose interactions with the central molecule often have strongly different contributions to the crystal energy. The idea of the energy coordination number of molecules is introduced. It is found that in compounds with similar structures this parameter can have diverse values that are not an unambiguous consequence of the number of hydrogen bonds formed by molecules or the number of molecules thus bonded to the central one.

To explore the role of the evolutionary conservative interhelical hydrogen bond (IHB) Ser74-Trp158 in maintaining the conformational stability of the β₂-adrenergic receptor, this work employs the molecular dynamics technique to study the conformational behavior of the receptor in the presence and absence of IHB. It is found that the Ser74-Trp158 IHB cleavage can cause further conformational transformations (helix shifts, change in the conformation of some amino acid residues). The S74A mutation in the receptor, which makes the IHB formation impossible, also leads to conformational changes: in the presence of cholesterol the mutated receptor takes a conformation close to the active form.

Electrospray ionization mass spectrometry is used to study thymidine solutions in the presence of copper ions and EDTA. The results show the existence of thymidine-EDTA complexes in the absence of CuCl₂ in solution and the existence of thymidine-EDTA-CuCl₂ complexes in a CuCl₂ and EDTA containing thymidine solution. The stoichiometry of the complexes is determined.

A study is presented of caffeine effects on the complexation of the DNA molecule with Cu²⁺ and Mg²⁺ ions in solution. DNA binding with cations and caffeine is captured from changes in DNA circular dichroism and UV absorption spectra. The complexation of caffeine with M²⁺ ions is studied by IR spectroscopy. Caffeine is found to form complexes of different structure with Mg²⁺ and Cu²⁺ ions in solution. In the presence of caffeine, DNA solutions with MCl₂ show signs of formation of intricate complexes involving nitrogenous bases. In DNA solutions with CuCl₂, the presence of caffeine causes additional destabilization of the secondary DNA structure. In DNA solutions with MgCl₂, the presence of caffeine leads to the formation of new complexes with the participation of Mg²⁺, caffeine, and bases without disrupting the secondary DNA structure.

The work considers DNA complexes with silver ions and a silver coordination compound containing phenanthroline ligands. The formation conditions of luminescent silver nanoclusters and nanoparticles having a plasmon resonance are analyzed. It is shown that nanoclusters form on reducing silver ions after the formation of their coordination bonds with nitrogenous bases of the macromolecule. The Ag(Phen)₂NO₃ compound cannot form such a bond and interacts with DNA by intercalating one of the phenanthroline ligands into a double helix. The preliminary binding of cis -DDP with DNA hinders the formation of silver nanoclusters.

In the work the properties of high-molecular DNA complexes with a photosensitive cationic azobenzene-containing surfactant capable of UV light induced trans-cis isomerization are studied. DNA compaction caused by its binding with surfactant cis- and trans-isomers is compared, the effect of the low-molecular NaCl salt concentration on the interaction process of the components is considered, and the effect of different surfactant concentrations on the volume and optical anisotropy of the DNA molecule is analyzed. The phase separation in solutions is examined.

In the cell culture experiments, the AEDL peptide proved to be an efficient agent stimulating the cell renewal processes and the enhancement of the functional activity of bronchial epithelial cells. A presumed target of the peptide action is a DNA molecule. The work studies the peptide binding with high-molecular DNA in solutions with different ionic strengths. The spectral (UV spectophotometery and circular dichroism) and hydrodynamic (viscosimetry) methods show that, under the experimental conditions, the AEDL peptide forms a complex with DNA and that nitrogen bases are involved in the binding. The character of spectral changes in DNA suggests a possible interaction of the AEDL peptide with DNA in the major furrow at the guanine N7 site without a visible distortion of the double helix structure.