Optical beaming of electrical discharges.

Igniting and guiding electrical discharges to desired targets in the ambient atmosphere have been a subject of intense research efforts for decades. Ability to control discharge and its propagation can pave the way to a broad range of applications from nanofabrication and plasma medicine to monitoring of atmospheric pollution and, ultimately, taming lightning strikes. Numerous experiments utilizing powerful pulsed lasers with peak-intensity above air photoionization and photo-dissociation have demonstrated excitation and confinement of plasma tracks in the wakes of laser field. Here, we propose and demonstrate an efficient approach for triggering, trapping and guiding electrical discharges in air. It is based on the use of a low-power continuous-wave vortex beam that traps and transports light-absorbing particles in mid-air. We demonstrate a 30% decrease in discharge threshold mediated by optically trapped graphene microparticles with the use of a laser beam of a few hundred milliwatts of power. Our demonstration may pave the way to guiding electrical discharges along arbitrary paths.

[The efficacy of cocarnit in diabetic neuropathy]. / Éffektivnost' preparata kokarnit pri diabeticheskoi neiropatii.

AIM: To study the efficacy of the complex therapy, including cocarnit (group B vitamins, triphosadenine and nicotinamide), of diabetic neuropathy. MATERIAL AND METHODS: Forty-one patients with diabetes mellitus type 2 and distal symmetric sensorimotor polyneuropathy were examined. Patients were divided into 2 groups. Patients of the main group (n=26) received complex therapy, including cocarnit, and patients of the comparison group (n=15) received standard treatment. RESULTS AND CONCLUSION: The positive dynamics based on the VAS (р=0.0001), TSS (р=0.0001), NSS (р=0.001), NDS (р=0.0431), SF-36 (р=0.0008), electroneuromyographic results and glycated hemoglobin levels was observed in the main group. In patients of the comparison group, the positive dynamics was instable; the scores of clinical scales did not reach statistical significance. The results suggest the use of cocarnit in the complex treatment of patients with diabetic neuropathy.

Laser-writing inside uniaxially birefringent crystals: fine morphology of ultrashort pulse-induced changes in lithium niobate.

This work presents a detailed analysis of the morphology of femtosecond laser-induced changes in bulk lithium niobate (LiNbO3) - one of the most common host materials in photonics - using second-harmonic generation microscopy and scanning electron microscopy. It is shown that focused linearly polarized near-infrared pulses can produce two or three distinct axially separated regions of modified material, depending on whether the pulse propagation is along or perpendicular to the optical axis. When laser writing in LiNbO3 is conducted in multi-shot irradiation mode and the focused light intensity is kept near the bulk damage threshold, periodic planar nanostructures aligned perpendicular to the laser polarization are produced inside the focal volume. These results provide a new perspective to laser writing in crystalline materials, including the fabrication of passive and active waveguides, photonic crystals, and optical data storage devices.

Visualizing polarization singularities in Bessel-Poincaré beams.

We demonstrate that an annulus of light whose polarization is linear at each point, but the plane of polarization gradually rotates by π radians can be used to generate Bessel-Poincaré beams. In any transverse plane this beam exhibits concentric rings of polarization singularities in the form of L-lines, where the polarization is purely linear. Although the L-lines are invisible in terms of light intensity variations, we present a simple way to visualize them as dark rings around a sharp peak of intensity in the beam center. To do this we use a segmented polarizer whose transmission axes are oriented differently in each segment. The radius of the first L-line is always smaller than the radius of the central disk of the zero-order Bessel beam that would be produced if the annulus were homogeneously polarized and had no phase circulation along it.

Transverse spin angular momentum of tightly focused full Poincaré beams.

We show theoretically that by tightly focusing a full Poincaré beam one can create states of light whose average spin angular momentum (SAM) is purely transverse. Moreover, the transverse SAM is significantly increased if a narrow annular aperture is inserted into the Poincaré beam. In this case the state with transverse SAM can exist over an extremely long distance along the optical axis. To avoid diffraction on the aperture and increase the light conversion efficiency we employ the phenomenon of conical diffraction in biaxial crystals to convert a Gaussian beam into a ring-shaped beam, with a high ratio of the ring radius to its width.

Optical vault: a reconfigurable bottle beam based on conical refraction of light.

We employ conical refraction of light in a biaxial crystal to create an optical bottle for photophoretic trapping and manipulation of particles in gaseous media. We show that by only varying the polarization state of the input light beam the optical bottle can be opened and closed in order to load and unload particles in a highly controllable manner.

Natural shaping of the cylindrically polarized beams.

We have experimentally and theoretically shown that the circularly polarized beam bearing a singly charged optical vortex propagating through a uniaxial crystal can be split after focusing into the radially and azimuthally polarized beams in the vicinity of the focal area provided that the polarization handedness and the vortex topological charge have opposite signs.

Focusing of wedge-generated higher-order optical vortices.

We experimentally show that when higher-order optical vortices generated by a system of dielectric wedges are subjected to focusing they do not lose their structural stability.

Generation of higher-order optical vortices by a dielectric wedge.

Diffraction of a Gaussian beam with a system of successively located optical wedges is considered. It is shown that the system is able to form higher-order optical vortices.

[Effect of perfluoroorganic compounds on growth of streptomycetes and biosynthesis of antibiotic daunorubicin]. / Vliianie perftoroorganicheskikh soedinenii na rost streptomitsetov i biosintez imi antibiotika daunorubitsina.

The use of perfluoroorganic compounds, i.e. perfluorodecalin and "Perftoran", a blood substitute with the gas transfer function, known as "blue blood" (containing 3 vol. % of perfluoromethylcyclohexylpiperidin and 7 vol. % of perfluorodecalin as emulsion with the average particle size of 0.07 microns) in biotechnology for intensification of the Streptomyces purpurogeniscleroticus growth under submerged conditions was shown promising for the first time. An increase of the biomass output and higher yields of daunorubicin were also demonstrated.

[Evaluation of the effect of dose rate and dose absorption on the long-term radiation consequences in rats chronically taking in 90Sr]. / Otsenka vliianiia moshchnosti dozy i pogloshchennoi dozy na otdalennye radiatsionnye posledstviia u krys pri khornicheskom postuplenii 90Sr.

The effects of exposure to 90Sr which was given with food with daily doses 18.5 kBq per animal for 1-12 months, 37 kBq per animal for 1-10 months, 74 kBq per animal for 1-8 months and 148 kBq per animal for 1-6 months on mortality patterns in unimbred white rats were investigated. Hazard models were used to evaluate dose rate and accumulated dose influence on radiation-related trends in mortality. The time-dependent risk of death from all causes and from osteosarcomas depended on the dose rate. The risk of death from causes other than osteosarcoma depended on the dose rate and the accumulated dose. To predict time-dependent risk of death it was better to use the least time to calculate the dose rate--1 day.

Electronic excitation as a mechanism of the ion selectivity filter.

A correlation between the character of pharmacological activity and the energies of electronic transitions in some biologically active molecules, affecting the nervous system, has been found. In order to explain the correlation, a new principle of the membrane ion selectivity filter has been suggested. The principle is based on the recombination process of a metal cation, passing through the filter, with an electron, when the energy quantum (equal to the metal ionization energy) is emitted. The amino acid residue group, performing the function of the channel filter, absorbs this quantum, transits itself into an electronically excited state, changes its conformation and lets, as a result, the cation pass. The process is possible only in that case when the amino acid residue group has a transition of the same energy, therefore not all of metals can pass through the filter. From the viewpoint of this conception, an active molecule acts because of its transition into an electronically excited state of the same energy and interfering, thereby, with the natural processes.

Inhibition of monoamine oxidase by pirlindole analogues: 3D-QSAR analysis.

A series of pirlindole analogues were tested as inhibitors of monoamine oxidase A and B. Although we did not find strict dependence between 3D-size of molecules and their inhibitory potency, rigid analogues exhibited potent and selective inhibition of MAO-A. They have 3D size limits of 13 angstroms (length) x 7 angstroms (height) x 4.4 angstroms (widths). Besides MAO-A inhibition flexible analogues also demonstrated potent inhibition of MAO-B. Five compounds were studied as inhibitors of purified human liver MAO-A. Their inhibitory potencies coincided with those obtained using rat liver mitochondrial MAO-A. Each compound induced changes in the spectrum of MAO-A but these did not correlate with the flexibility of the derivative. It is also possible that the oxygen bridge introduced with the flexibility might influence spectral patterns.

Inhibition of monoamine oxidase by pirlindole analogues: 3D-QSAR and CoMFA analysis.

A series of pyrazinocarbazoles, analogues of short acting antidepressant pirlindole (2,3,3a,4,5,6-hexahydro-8-methyl-1H-pyrazino[3,2,1-j,k]carbazole hydrochloride), were tested as inhibitors of monoamine oxidase A (MAO-A) and B (MAO-B). Rigid analogues exhibited potent and selective inhibition of MAO-A and have size limits (X:Y:Z) of 13.0 x 7.0 x 4.4 A. Besides MAO-A inhibition flexible analogues also demonstrated potent inhibition of MAO-B and in contrast to rigid analogues their inhibitory activity did not show the dependence on these sizes. The qualitative information (steric and electrostatic coefficients) from the 3D-QSAR with CoMFA models for MAO-A and -B are different, and this information can be used to determine the structural features influencing inhibitor selectivity.

The influence of the antidepressant pirlindole and its dehydro-derivative on the activity of monoamine oxidase A and GABAA receptor binding.

The influence of pirlindole and dehydro-pirlindole on GABAA receptor binding and MAO-A activity was investigated in vitro. Inhibition of rat brain and human placenta MAO-A by both compounds was much more potent (with IC50 range 0.3-0.005 microM) than that of GABAA receptors. Pirlindole was inactive as a GABA antagonist. Dehydro-pirlindole exhibited selective blockade of GABA-A receptors with EC50 12 microM. Effects of both compounds on MAO-A activity were partially reversible. Data obtained suggest that in contrast to pirlindole dehydro-pirlindole may act not only as a MAO-A inhibitor but also as a potent GABAA receptor blocker.

[The creation of original Russian beta-adrenoblockers]. / Sozdanie otechestvennykh original'nykh beta-adrenoblokatorov.

Results of search for new beta-adrenoreceptor blocking agents of different effects are summarized. Derivatives of 4-hydroxyindolyl-3-acetic acid are characterized by a prolonged beta-adrenoblocking effect, cardioselective beta-adrenoblockers were found among derivatives of N,N-bis(2-hydroxy-3-phenoxypropanol)amine, and highly effective "hybrid" beta-,a-adrenoblockers were detected among derivatives of 3(5)-phenoxymethylisoxazolines and 5-phenoxymethyl-1,2,4,-oxadiasoles. Clinical studies of one of the most promising compounds of the latter series named proxodolol showed it to be a highly effective antihypertensive, antianginal, and antiglaucoma drug. Proxodolol is permitted for clinical application. At present it is manufactured as eye drops for decreasing intraocular pressure in glaucoma; its production as a solution for injections for arresting hypertensive crises is starting.

[Biological effects of acute external or internal irradiation of rats in the framework of nitrite intoxication]. / Biologicheskoe deistvie ostrogo vneshnego ili vnutrennego oblucheniia krys na fone nitritnoi intoksikatsii.

The material presented provides evidence that high nitrite doses have a various effect under the condition of external or internal radiation. Thus, nitrite protector properties were observed in male rats exposed to external radiation using the LD50/30 while following 90Sr exposure male rats of the same age showed a higher sensitivity to the radionuclide. The nitrite combined with optimum carcinogenic 90Sr dose had a potentiating effect on both life-span shortening and increase in osteosarcoma rate in the animals.

Effects of the antidepressant pirlindole and its dehydro-derivative on the activity of monoamine oxidase-A and on GABAA receptors.

The effects of pirlindole and dehydro-pirlindole on GABAA receptors and MAO-A activity were investigated in vitro. Pirlindole was inactive as a GABA antagonist. Dehydro-pirlindole exhibited partial and selective blockade of a subset of GABAA receptors with an EC50 of 12 microM and maximum reversal (delta Bopt) of 42%. Inhibition of rat brain and human placenta MAO-A by both compounds was much more potent (with IC50 range 0.3-0.005 microM). Their effects on MAO-A activity were partially reversible in vitro. In contrast to pirlindole, dehydro-pirlindole may act not only as MAO-A inhibitor but also as a clozapine-like selective GABAA receptor blocker, preferentially blocking a subset of GABAA receptors that are not sensitive to DMCM or Ro 5-4864.

[Schematic model of genesis of osteosarcoma induced by Sr-90]. / Skhematicheskaia model' osteosarkomogeneza, indutsirovannogo 90Sr.

The development of radiation osteosarcoma genesis scheme induced by 90Sr was the subject of the present study. The production of cancer cells after exposure to a specific dose-rate of emitting 90Sr incorporated in the skeleton are typical for the initiation period. However not all the cells remain in the mutant DNA. In some of them DNA reparation occurs, other cells are killed in the process of the subsequent divisions, and only a few of them containing mutant DNA are preserved in the state of repression up to the end of life time. Disorders of homeostasis due to exhausted of physiological reserves - (natural or early aging) are manifested as a promoter. In that period the derepression of mutant DNA occurs and malignant growth of tumor starts.