Broadband and fine-structured luminescence in diamond facilitated by femtosecond laser driven electron impact and injection of "vacancy-interstitial" pairs.

Ultrafast heating of photoionized free electrons by high-numerical-aperture (0.25-0.65) focused visible-range ultrashort laser pulses provides their resonant impact trapping into intra-gap electronic states of point defect centers in a natural IaA/B diamond with a high concentration of poorly aggregated nitrogen impurity atoms. This excites fine-structured, broadband (UV-near-infrared) polychromatic luminescence of the centers over the entire bandgap. The observed luminescence spectra revealed substitutional nitrogen interaction with non-equilibrium intrinsic carbon vacancies, produced simultaneously as Frenkel "vacancy-interstitial" pairs during the laser exposure.

Ab initiocalculations of the phase diagrams of tin and lead under pressures up to a few TPa.

The paper studies relative structural stability for various crystal phases of tin and lead from first principles with the full-potential all-electron full-potential all-electron linear muffin-tin orbital method to pressures of a few TPa both at zero temperature and atT> 0. Using data from our calculations we construct phase diagrams for the two metals in the region of very high compressions and obtain their melting curves. For tin at pressures <100 GPa and zero temperature, we did not find the region of stability of the body-centered orthorhombic (bco) phase, as it was earlier observed in experiments by Salamatet al[2013Phys. Rev.B88104104]. Our calculations suggest that one structural transition from the tetragonal to cubic phase, bct → bcc, occurs in perfect Sn crystal atT= 0 K in the pressure range of about 27-32 GPa. But any deviation from perfection may cause an orthorhombic distortion of its tetragonal phase. At pressures above 100 GPa, the bcc → hexagonal close-packed (hcp) transition exists in both metals, and the phase boundary has a domed shape and does not rise in temperature above 2 kK. This behavior of the phase boundary with the increasing temperature is caused by the softer phonon modes of the bcc structure and the smaller contribution of lattice vibrations to the free energy of the crystal compared to the hcp phase. At pressures above 2.5 TPa andT≲ 1 kK, lead can also undergo another structural transition, hcp → fcc, but atT> 1.5 kK there must exist the more energetically preferable bcc → fcc transition.

A wide-range multiphase equation of state for platinum.

The paper presents a semi-empirical wide-range equation of state (EOS) for platinum with account for melting, evaporation, and ionization. The equation is based on a wide spectrum of experimental and calculation data. Parameters for the EOS were adjusted using a genetic algorithm which proved to perform well for optimizations in big data processing. In the regions where no experimental data were available, we used results of first-principles and average-atom model calculations. The EOS was used to calculate the melting curve of platinum to pressures above 1 TPa, sound velocities along the Hugoniot curve, parameters of melting under shock compression, and parameters of the critical point. An improved model is proposed for the shear modulus in (V, T) coordinates and its variation along the shock adiabat is calculated.

Highly efficient stimulated Raman scattering of sub-picosecond laser pulses in BaWO4 for 10.6 µm difference frequency generation.

Transient stimulated Raman scattering (SRS) of 0.3 ps 515 nm laser pulses in ${\rm BaWO_4}$BaWO4 crystal was experimentally demonstrated with efficiency up to ${\sim}{20}\% $∼20% for the Stokes component with a wavenumber of ${\sim}{925}\;{{\rm cm}^{ - 1}}$∼925cm-1 in a simple single-pass geometry. This anomalous high efficiency was obtained due to the laser pulse self-phase modulation resulting in spectral broadening and seeding the SRS. The applicability of seed pulse production for a high-pressure sub-picosecond ${{\rm CO}_2}$CO2 laser amplifier via difference frequency generation in ${{\rm LiGaS}_2}$LiGaS2 crystal was numerically verified.

IR femtosecond laser micro-filaments in diamond visualized by inter-band UV photoluminescence.

Single microscale filaments were produced in monocrystalline Ia-type diamond by 1030 nm, 300 fs laser pulses tightly focused at NA = 0.3 and different peak powers, visualized by transverse imaging and spectrally characterized by longitudinal micro-spectroscopy, using intrinsic UV A-band photoluminescence (PL) with its peak at about 430 nm. Power-dependent scaling relationships for the local PL yield and diameters of the accompanying luminous micro-channels of recombining electron-hole plasma indicate a transition from three-photon absorption to free-carrier plasma absorption, as the consequent energy deposition mechanisms at increasing peak laser power. Power-dependent elongation of the luminous micro-channels versus peak laser power fitted by a Marburger formula yields, on average a diffraction-based estimate of 0.6 MW critical power for self-focusing within the diamond at the pump laser wavelength of 1030 nm.

Ab initio calculations of the elastic and thermodynamic properties of gold under pressure.

The paper presents first-principles FP-LMTO calculations on the relative stability of fcc, bcc, hcp and dhcp gold under pressure. They were done in local density approximation (LDA), as well as in generalized gradient approximation (GGA) with and without spin-orbit interaction. Phonon spectra for the considered gold structures were obtained from LDA calculations within linear response theory and the contribution of lattice vibrations to the free energy of the system was determined in quasiharmonic approximation. Our thorough adjustment of FP-LMTO internal parameters (linearization and tail energies, the MT-sphere radius) helped us to obtain results that agree well with the available experimental phase relation Dubrovinsky et al (2007 Phys. Rev. Lett. 98 045503) between fcc and hcp structures of gold under pressure. The calculations suggest that gold compressed at room temperature successively undergoes the following structural changes: [Formula: see text]. The paper also presents the calculated elastic constants of fcc, bcc and hcp Au, the principal Hugoniot and the melting curve. Calculated results were used to construct the PT-diagram which describes the relative stability of the gold structures under study up to 500 GPa.

In trans promoter activation by enhancers in transient transfection.

Earlier, it was reported that the strong cytomegalovirus enhancer can activate the cytomegalovirus promoter in trans, i.e. as a separate plasmid co-transfected with a promoter-reporter gene construct. Here we demonstrate that the ability of enhancers to activate promoters in trans in transient transfection experiments is a property of not only viral regulatory elements but also of various genomic enhancers and promoters. Enhancer-promoter activation in trans is promoter- and cell type-specific, and accompanied by physical interaction between promoter and enhancer as revealed by chromosome conformation capture assays. Thus, promoter activation in transient co-transfection of promoters and enhancers shares a number of important traits with long-distance promoter activation by enhancers in living cells and may therefore serve as a model of this fundamental cellular process.

Assay of insulator enhancer-blocking activity with the use of transient transfection.

We used a transient transfection of cultured cells with linearized plasmids to analyze the enhancer-blocking activity of potential insulators including the standard cHS4 chicken beta-globin insulator and several DNA fragments selected from the human genome sequence. About 60-80% of the potential insulators do reveal the enhancer-blocking activity when probed by the transient transfection assay. The activity of different sequences is characterized by certain tissue specificity and by dependence on the orientation of the fragments relative to the promoter. Thus, the transfection model may be used for quantitative analysis of the enhancer-blocking activity of the potential insulators.

Human PSENEN and U2AF1L4 genes are concertedly regulated by a genuine bidirectional promoter.

Head-to-head genes with a short distance between their transcription start sites may constitute up to 10% of all genes in the genomes of various species. It was hypothesized that this intergenic space may represent bidirectional promoters which are able to initiate transcription of both genes, but the true bidirectionality was proved only for a few of them. We present experimental evidence that, according to several criteria, a 269 bp region located between the PSENEN and U2AF1L4 human genes is a genuine bidirectional promoter regulating a concerted divergent transcription of these genes. Concerted transcription of PSENEN and U2AF1L4 can be necessary for regulation of T-cell activity.

Functional dissection of an enhancer-like element located within the second intron of the human U2AF1L4 gene.

A detailed functional and evolutionary analysis of an enhancer element of the human genome (enhancer 12) located in the second intron of the U2AF1L4 gene, which we identified earlier, is presented. Overlapping fragments of the studied genome region were analyzed for enhancer activity, and the site responsible for the activity of this element was identified using transient transfections of HeLa cells. Comparison of the enhancer 12 sequence with orthologous sequences from seven primate species revealed the existence of evolutionarily conserved sequences within this element. One of the identified conservative regions is likely responsible for the enhancer activity and is able to specifically interact in vitro with proteins of HeLa cell nuclear extract. The ability of orthologous primate sequences to compete with enhancer 12 for binding with HeLa cell nuclear extract proteins and to enhance the activity of the reporter gene in transient transfection of HeLa cells is demonstrated.

Pseudopotential and full-electron DFT calculations of thermodynamic properties of electrons in metals and semiempirical equations of state.

In the present work, we compare the thermal contribution of electrons to thermodynamic functions of metals in different models at high densities and electron temperatures. One of the theoretical approaches, the full-potential linear-muffin-tin-orbital method, treats all electrons in the framework of density functional theory (DFT). The other approach, VASP, uses projector-augmented-wave pseudopotentials for the core electrons and considers the valent electrons also in the context of DFT. We analyze the limitations of the pseudopotential approach and compare the DFT results with a finite-temperature Thomas-Fermi model and two semiempirical equations of state.

[Evaluation of cell nitrogen and phosphorus quotas in accumulative cultures of chlorococcous algae]. / Otsenka kletochnykh kvot azota i fosfora v nakopitel'nykh kul'turakh khlorokokkovykh vodoroslei.

A conceptual model of cell quota was proposed and the parameters were determined that characterize the quota dynamics during the development of algae. Based on the experimental and empirical-statistical procedures of analysis, the basal parameters of cell quotas of nitrogen and phosphorus were obtained for four species of chlorococcous algae. The data were also obtained on a variability of nitrogen and phosphorus quotas during the development of algae, as well as coefficients of excessive accumulation. The phosphorus quota changed within the limits of three orders of magnitude and the nitrogen quota, within the limits of one order. The highest coefficients of excessive accumulation were 52 and 1.8 for phosphorus and nitrogen, respectively.

[Prognostication of the outcome of heart valve prosthesis implantation by the method of nonlinear chaos dynamics of the heart rate]. / Prognozirovanie iskhodov protezirovanii klapanov serdtsa s pomoshch'iu metoda nelineinoi khaoticheskoi dinamiki kardioritma.

An examination of 39 patients with heart diseases was performed before and after operations by the method of geometrical analysis of the nonlinear chaos (fractal) variability of the cardiac rhythm on the basis of the apparatus-programmed complex "Poly-spectrum". Five-minute-long registrations of ECG were carried on. On the basis of the data of examination of 195 healthy volunteers the reference norm of this method parameters was determined. Reliably lower parameters were found in patients with the acquired valvular disease. A dynamic investigation of the geometrical nonlinear structure of the cardiac rhythm has shown the possibility to make a prognosis of early complications after prosthetics of the heart valves.

[Anastomoses between the meningeal arteries and the cavernous sinus: the clinical picture, diagnosis and treatment]. / Soust'ia mezhdu meningeal'nymi arteriiami i kavernoznym sinusom: klinika, diagnostika, lechenie.

The findings of 106 patients with arteriosinus anastomoses formed by the meningeal arteries and cavernous sinus were analyzed. The clinical symptoms, the specific features of the course of this abnormality and the principle of its diagnosis are summarized. Based on angiographic data, 4 types of anastomoses were identified by X-ray and anatomic signs: 1) the anastomoses formed by the meningeal branches of the internal carotid and cavernous sinus (45.4%); 2) those formed by the branches of the external carotid and cavernous sinus (9.3%); 3) the branches of both the internal and external carotids are involved in anastomotic blood supply (38.1%); 4) a combination of carotid-cavernous and arteriosinus anastomoses (7.2%). According to the sources of blood supply, the patients received endovascular treatment (external carotid branch embolization, fistula balloon occlusion), radiation surgery or combined treatment. The differential approach to treating patients with arteriosinus anastomoses at the site of the cavernous sinus yielded good results in 78.9% of cases.

[Change in neutrophils in liquidators of the consequences of the accident at the Chernobyl Atomic Electric Power Station]. / Izmenenie neitrofilov u likvidatorov posledstvii avarii na Chernobyl'skoi AES

In result of own researches and analysis of the literature? the information about high sensitivity of neutrophils of peripheric blood to infringements of constancy of internal state of body, arising as reply to radiating influence, are received. Ionized radiation modulates greatly properties and functions of neutrophilic granulocytes, which are the most sensitive and high-modulated cells of non-specific resistance system. The changes of the functional-metabolic status of neutrophils in participants of liquidation of consequences of Chernobyl disaster have been saving during 10 years after influence of the extreme, including radiating, factors of failure.

[Effects of cystamine on the state of peripheral blood neutrophilic granulocytes in vivo in rats]. / Vliianie tsistamina na sostoianie neirofil'nykh granulotsitov perifericheskoi krovi krys in vivo.

It has been found experimentally, that decay of the intercellular energy exchange, intensification of the secretory degranulation, activation of the oxygen-dependent enzyme system and increasing the functional potential of the male-rats neutrophils took place on the height of the protective action of cystamine. On the 1-st day the tendency to restoration was noted and the normalisation of the functional and metabolical status of the neutrophils could be seen on the 5-th day after injection.