Influence of the pumping wavelength on laser properties of Fe2+ ions in ZnSe crystal.

ZnSe:Fe2+ active laser crystal properties at different excitation wavelengths (2.94 and 4.1 µm) were investigated, and noticeable variations of the fluorescence spectra shape and their maxima positions, as well as changes in decay times, were observed. A stepwise shift of the laser oscillation wavelength from 4.7 µm at 2.94 µm pumping to 4.95 µm at 4.1 µm pumping was achieved at room temperature.

Room temperature Fe2+:Cd1-xMnxTe laser generating at 5.4-6 µm.

Six-µm laser generation at room temperature was achieved from Fe2+-doped Cd1-xMnxTe solid-solution active media for the first time, to the best of our knowledge. Laser properties of Fe2+:Cd1-xMnxTe crystals with various concentrations of manganese Mn (x=0.1, 0.52, 0.56, 0.68, and 0.76) were investigated. The increase of Mn content in these crystals was shown to result in an almost similar long-wavelength shift of absorption, fluorescence, and laser output spectra of about ∼60 nm per each 10% of Mn. Laser generation was achieved in all crystals with maximum output energies up to 30 µJ (for x=0.52). The laser central oscillation wavelength is significantly influenced by Mn concentration and varies in the range from 5400 nm up to 6000 nm.

Spectroscopic and laser properties of bulk iron doped zinc magnesium selenide Fe:ZnMgSe generating at 4.5 - 5.1 µm.

The Fe:Zn(1-x)Mg(x)Se (x = 0.19, 0.27, and 0.38) solid solutions spectroscopic properties were investigated and laser oscillations were achieved for the first time. The increase of the magnesium concentration in the Fe:ZnMgSe crystal was shown to result in an almost similar long wavelength shift of both absorption and fluorescence spectra of about 60 nm per each 10% of magnesium. With the Fe:ZnMgSe crystal temperature decrease, the fluorescence spectrum maximum shifts towards shorter wavelength resulting mainly from strong narrowing of the longest wavelength fluorescence line. Laser radiation wavelength dependence on the magnesium concentration as well as on temperature was observed. The Fe:ZnMgSe x = 0.38 laser oscillation wavelength increased from 4780 nm at 80 K to 4920 nm at 240 K using the optical resonator without any intracavity spectrally-selective element. In comparison with the Fe:ZnSe laser operating in similar conditions, these wavelengths at both temperatures were shifted by about 500 nm towards mid-IR region.

Gene expression of H+-pumps in plasma and vacuolar membranes of corn root cells under the effect of sodium ions and bioactive preparations.

Four isoforms of H+-ATPase of plasma membrane: MHA1, MHA2, MHA3, MHA4 are expressed in the corn seedling roots with prevalence of genes MHA3 і MHA4. The exposure of seedlings in the presence of 0.1 M NaCl activated the expression of MHA4 gene isoform, that demonstrates its important role in the processes of adaptation to salinization conditions. In vacuolar membrane, where potential is created by two Н+-pumps, sodium ions activated gene expression of only Н+-АТРase of V-type, taking no effect on the expression of Н+-pyrophosphatase. The seeds pretreatment by synthetic preparations Methyure and Ivine did not affect gene expression of Н+-pumps. Thus we can suppose that the ability of the above preparations to activate functioning of Н+-pumps in the presence of sodium ions is realized at the post-tranlation level.

[Effect of adaptogenic preparations on Na+/H+-antiporter function in plasma membrane of corn root cells under salinity conditions].

Salinity is a hard stress factor for plant organisms which negative effect is caused chiefly by sodium toxic for plants. Plant cells try to remove Na+ from their cytoplasm outside and to vacuolar space by secondary active Na+/H+-antiporters. Their functions can be intensified by gene engineering methods however we try do it with the help of non-toxic bioactive preparations. A comparison of their effect on the plasma membrane of Na+/H+-antiporters was carried out on corn seedling roots of Zea mays L. exposed at 0.1 M NaCl. Before we have established that Methyure used by seed pretreating possesses a high salt protective ability as against Ivine. It was found that without NaCl exposition Na+/H+-antiporter activity in root plasma membrane was nearly unnoticeable but increased slightly with seedling age. Methyure and Ivine did not influence its activity in control root seedling. One day 0.1 M NaCl exposition evoked a considerable increasing of Na+/H+-antiporter activity and its gene expression but these effects disappeared at 10 day NaCl exposition. Methyure use reinforced Na+/H+-antiporter activity and prolonged it at NaCl exposition without effect on its gene expression whereas Ivine effects on these indexes were insignificant. Obtained results showed that the salt protective capability of Methyure is connected with plasma membrane Na+/H+-antiporter activation which is realized on molecular level.