Laser-induced photodynamic effects of chlorinse 6 andp 6 on an isolated neuron

Photodynamic effects of chlorins e₆ and p₆ on an isolated mechanoreceptor neuron of a fluvial crayfish are investigated. A He−Ne laser (632.8 nm, 0.3 W/cm²) was used as an excitation source. The impulsive activity of neurons was found to be extremely sensitive to the photodynamic effect of low concentrations of chlorins e₆ and p₆ (0.005–6.000 and 0.05–0.50 μM, respectively). Cell reactions consisted of several phases of acceleration and inhibition of pulsations followed by an irreversible cancellation of nervous pulse generation. The type of reaction depended on the photosensitizer form and concentration. It is supposed that the phases of acceleration of impulsive activity are connected with the photodynamic damage of the cell membrane, and the inhibition phases are connected with the photodynamic effect on intracell organells. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 2, pp. 250–255, March–April, 1999.     

Spectral composition of the light from plasmas created by electron beams in nitrogen and He-N2 and Ne-N2 mixtures

Plasmas created by electron beams in N₂ and He-N₂ and Ne-N₂ mixtures at high pressures are studied experimentally. It is shown that N ₂ ⁺ ions in the B² _u ⁺ state are produced during charge exchange of Ne ₂ ⁺ ions with N₂ molecules. A comparison of the intensity of light from the B² _u ⁺ X² _g ⁺ transition of the N ₂ ⁺ ion in He-N₂ and Ne-N₂ mixtures shows that under these experimental conditions charge exchange of Net ions with N₂ is less effective than the analogous process involving He ₂ ⁺ ions. It is found that in an Ne-N₂ mixture the intensity of emission on transitions of the 2^t system of nitrogen is greater than in N₂.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 57–61, December, 1977.     

Regularities in the Sorption Recovery of Osmium in Various Oxidation States (VIII, VI, and IV) on Silica Chemically Modified with Thiourea Derivatives

Regularities in the sorption recovery of osmium(VIII, VI, IV) on silica chemically modified with thiourea derivatives (N-allyl-N"-propylthiourea (ATUS), N-phenyl-N"-propylthiourea (PTUS), and N-benzoyl-N"-propylthiourea (BTUS)) were studied. The equilibrium attainment time for the solid-phase extraction of osmium(VIII) is 15, 30, and 40 min for ATUS, PTUS, and BTUS, respectively. For the solid-phase extraction of osmium(VI), equilibrium attainment time is independent of the type of the sorbent and is no more than 5 min. The recovery of osmium(IV) at 95°C and equilibration time 120 min is no higher than 5%. The quantitative recovery of osmium(IV) with silica chemically modified with thiourea derivatives is attained on long-term heating and in the presence of tin(II) chloride. Based on the regularities in the sorption recovery of osmium in different oxidation states and its interaction with thiourea in aqueous solutions with low mole ratios, it was suggested that osmium(VIII, VI) and osmium(IV) interact with thiourea and its derivatives including those covalently bonded to the silica surface via different mechanisms.     

Electron-beam-pumped high-power wide-aperture exciplex lasers and laser systems

High-efficiency, high-power pulsedXeCl ^* andKrF ^* lasers pumped with an electron beam and laser systems based on these lasers have been developed. This paper describes the principles embodied in their development and design. The results of investigations on the formation of high-quality, high-power pulses are presented. Pulses with a radiation energy of up to 2000 and 100 J have been obtained at λ=308 and 249 nm, respectively, with a minimum 10 μrad divergence of the beam. Institute of High-Current Electronics, Siberian Division of the Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 12–18, April, 2000.     

The behavior of bounded solutions to the equation Δu−c(x)u=0 on riemannian manifolds of special type

In the paper we consider solutions of the equation Δu−c(x)u=0,c(x)≥0, on complete Riemannian manifolds constituted as follows: the exterior of some compact set is isometric to the direct product of the semiaxis by some compact manifold with the metricds ²=h ²(r)dr ²+g ²(r)dθ². Necessary and sufficient conditions under which bounded solutions of the equation have a limit independent of θ asr→∞ are obtained and also conditions under which the two-sided Liouville theorem is valid. Translated fromMatematicheskie Zametki, Vol. 65, No. 2, pp. 215–221, February, 1999.     

Influence of Nanoscale Titanium Dioxide Modifications on the Nano-Organization of Elastomers

Crystallography Reports - The diffraction patterns of fluorine rubbers ICF-26 and ICF-32 and vulcanizates based on ICF-32 with nanoscale titanium dioxide modifications are found to contain...     

Adsorption-luminescence determination of copper concentration using silica gel chemically modified with <Emphasis Type="Italic">N</Emphasis>-(1,3,4-thiadiazol-2-thiol)-<Emphasis Type="Italic">N</Emphasis>′-propylurea groups

Silica gel chemically modified with 1,3,4-thiadiazol-2-thiol groups recovered 99% of the copper(II) from solutions of pH 4–6; the adsorption equilibrium was attained in no more than 5 minutes. During irradiation with ultraviolet light, a yellow-orange luminescence (λ_max = 575 nm) of surface copper complexes appeared in the phase of adsorbent cooled to 77 K; it was used as an analytical signal in the procedure for the low-temperature adsorption-luminescence determination of copper concentration. The detection limit was 0.3 μ g/0.1 g adsorbent. The calibration graph was linear up to 50 μg/0.1 g adsorbent. The determination of copper concentration is not affected by 10000-fold amounts of Zn(II), Cd(II), Mn(II), Co(II), Ca(II), Mg(II), and Al(III) and 300-fold amounts of Fe(III). The procedure was used to determine copper concentration in natural and technogenic waters.     

Lasing from an electron-beam-excited nonchain HF laser

The lasing parameters of a nonchain chemical HF laser (an active volume of 20 l) excited by a fast electron beam are studied at different energies delivered to the gas. It is shown that the laser operates efficiently when the energy deposited is below 30 J/l. Above specific excitation energies of 60–70 J/l, both the lasing efficiency and the laser output decrease.