Effects of 10-(6′-plastoquinonyl) decyltriphenylphosphonium (SkQ1) and 10-(6′-plastoquinonyl) decylrhod-amine 19 (SkQR1) on rat models of H
2
O
2
- and ischemia-induced heart arrhythmia, heart ...infarction, kidney ischemia, and stroke have been studied
ex vivo
and
in vivo
. In all the models listed, SkQ1 and/or SkQR1 showed pronounced protective effect. Supplementation of food with extremely low SkQ1 amount (down to 0.02 nmol SkQ1/kg per day for 3 weeks) was found to abolish the steady heart arrhythmia caused by perfusion of isolated rat heart with H
2
O
2
or by ischemia/reperfusion. Higher SkQ1 (125–250 nmol/kg per day for 2–3 weeks) was found to decrease the heart infarction region induced by an
in vivo
ischemia/reperfusion and lowered the blood levels of lactate dehydrogenase and creatine kinase increasing as a result of ischemia/reperfusion. In single-kidney rats, ischemia/reperfusion of the kidney was shown to kill the majority of the animals in 2–4 days, whereas one injection of SkQ1 or SkQR1 (1 μmol/kg a day before ischemia) saved lives of almost all treated rats. Effect of SkQR1 was accompanied by decrease in ROS (reactive oxygen species) level in kidney cells as well as by partial or complete normalization of blood creatinine and of some other kidney-controlled parameters. On the other hand, this amount of SkQ1 (a SkQ derivative of lower membrane-penetrating ability than SkQR1) saved the life but failed to normalize ROS and creatinine levels. Such an effect indicates that death under conditions of partial kidney dysfunction is mediated by an organ of vital importance other than kidney, the organ in question being an SkQ1 target. In a model of compression brain ischemia/reperfusion, a single intraperitoneal injection of SkQR1 to a rat (1 μmol/kg a day before operation) effectively decreased the damaged brain area. SkQ1 was ineffective, most probably due to lower permeability of the blood-brain barrier to this compound.
A 60 mW output power has been achieved in mid‐UV (λ = 270 nm) spontaneous sources with electron‐beam pulse‐scanning pumping, fabricated from AlGaN MQW heterostructures grown by PA MBE on c‐Al2O3 ...substrates. Under the CW pumping at much lower excitation power density the mid‐UV sources demonstrate a 4.7 mW output power. In that regime the power efficiency of the structures is about 0.24%, while their internal quantum efficiency is estimated to be as high as 50%.
•Nanocomposite based on ZnO and colloidal CsPbBr3 nanocrystals was synthesized.•CsPbBr3 nanocrystalls sensitize photoconductivity ZnO in the visible range.•Periodic illumination was used for ...light-activated NO2 detection.•Tuning metal-oxide sensors performance by slight heating and light illumination.•Lead halide perovskite nanocrystals for gas sensing application were used.
The development of sensor materials of which gas sensitivity activates under light illumination is of great importance for the design of portable gas analyzers with low power consumption. In the present work a ZnO/CsPbBr3 nanocomposite based on nanocrystalline ZnO and colloidal cubic-shaped perovskite CsPbBr3 nanocrystals (NCs) capped by oleic acide and oleylamine was synthesized. The individual materials and obtained nanocomposite are characterized by x-ray diffraction, low-temperature nitrogen adsorption, x-ray photoelectron spectroscopy, high angle annular dark field scanning transmission electron microscopy with energy-dispersive X-ray spectroscopy mapping and UV–vis absorption spectroscopy. The spectral dependence of the photoconductivity of the ZnO/CsPbBr3 nanocomposite reveals a well-defined peak that strongly correlates with the its optical absorption spectrum. The nanocomposite ZnO/CsPbBr3 shows enhanced photoresponse under visible light illumination (λmax = 470 nm, 8 mW/cm2) in air, oxygen and argone, compared with pure nanocrystalline ZnO. Under periodic illumination in the temperature range of 25−100 °C, the ZnO/CsPbBr3 nanocomposite shows a sensor response to 0.5–3.0 ppm NO2, unlike pure nanocrystalline ZnO matrix, which demonstrates sensor sensitivity to NO2 under the same conditions above 100 °C. The effects of humidity on the sensor signal and photoresponse are also discussed.
•Multi quantum well CdS/ZnSe structures are promising for a semiconductor disk laser.•Current probe microscopy can be used to diagnose type II heterostructure.•A depth-non-uniform deformation of ...quantum wells is observed in the structure.•Interdiffusion of Cd and Zn deteriorates laser performance
CdS/ZnSe multi quantum well (MQW) heterostructures with type II band offsets for blue-green semiconductor disk lasers were grown by metalorganic vapor-phase epitaxy (MOVPE) at T = 440 °C. The blurring of heterostructure interfaces during growth is investigated. There has been observed a blueshift of the emission line of heterostructures pumped from the side released from the GaAs substrate, in comparison with the emission line under pumping from the growth surface that indicates the change in the design of QWs during growth. Simulations of experimental X-ray diffraction curves also showed that the average composition of QW changes on CdZnS/ZnCdSe. It is shown that due to the strong mutual diffusion of Cd and Zn through the interfaces, it is possible to form the two ZnSSe/ZnCdSe/ZnCdS QWs with the I-type band offsets. Nevertheless, using light-assisted spreading resistance microscopy measurements on the cleaved cross-sections of the structures, carrier separation in QWs is observed, indicating the formation of a type II band offsets in the most of our heterostructures. The grown structures show intense luminescence, the radiation spectrum of which shifts to the short-wave side with the increase of the pump level.
An important role of the early Neoproterozoic juvenile crustal growth in the formation of the Khangai group of Precambrian terranes in the Central Asian Orogenic Belt was demonstrated by the example ...of the Holbo Nur Zone of the Songin Block. Magmatic complexes of this zone correspond to different settings of the Early Neoproterozoic ocean: oceanic islands, mid-ocean ridges, intraoceanic island arcs, and turbidite basins. Obtained data on volcanic rocks and associated granitoids constrain a timing of the island-arc magmatic complexes, at least within the interval of 888–859 Ma. The comparison of structures of the Songino and Tarbagatai blocks of the Khangai group of terranes showed that they share many common features in their geology and evolution and may be united into the single Songino–Tarbagatai terrane. This terrane was formed owing to the Early Neoproterozoic (~800 Ma) accretion of the ocean island, spreading, island-arc, and turbidite complexes of the oceanic plate to a stable continental massif represented by the Early Neoproterozoic Ider Complex of the Tarbagatai Block. The involvement of the Dzabkhan terrane into a Khangai collage of terranes is constrained between the formation of the volcanic rocks of the Dzabkhan Formation (~770–755 Ma), which are unknown in the Songino–Tarbagatai terrane, and the Tsagaan-Olom carbonate cover (~630 Ma), overlying both the Dzabkhan and Songino–Tarbagatai terranes. It was proposed that the formation of the Precambrian terranes of the Central Asian Orogenic Belt began from the Early Neoproterozoic accretion to the Rodinia supercontinent. The fragmentation of the latter above a mantle superplume at the end of the Early Neoproterozoic spanned also the newly formed fold area. This led to the formation of terranes, which included both fragments of the Paleoproterozoic craton and Early Neoproterozoic structures. Subsequent amalgamation of these Precambrian crustal fragments into composite terranes possibly occurred at the end of the early Baikalian tectonic phase.
Data on the composition, inner structure, and magma sources of giant batholith in the Central Asian Orogenic Belt are analyzed with reference to the Khangai batholith. The Khangai batholith was ...emplaced in the Late Permian–Early Triassic (270–240 Ma) and is the largest accumulations (>150000 km
2
) of granite plutons in central Mongolia. The plutons are dominated by granites of normal alkalinity and contain subalkaline granites and more rare alkaline granites. The batholith is hosted in the Khangai zonal magmatic area, which consists of the batholith itself and surrounding rift zones. The zones are made up of bimodal basalt–trachyte–comendite (pantellerite) or basalt-dominated (alkaline basalt) volcanic associations, whose intrusive rocks are dominated by syenite and granite, granosyenite, and leucogranite. Both the batholith and the rift zones were produced within the time span of 270–240 Ma. Although the rocks composing the batholith and its rift surroundings are different, they are related through a broad spectrum of transitional varieties, which suggests that that the mantle and crustal melts could interact at various scale when the magmatic area was produced. A model is suggested to explain how the geological structure of the magmatic area and the composition of the magmatic associations that make up its various zones were controlled by the interaction between a mantle plume and the lithospheric folded area. The mantle melts emplaced into the lower crust are thought to not only have been heat sources and thus induced melting but also have predetermined the variable geochemical and isotopic characteristics of the granitoids. In the marginal portions of the zonal area, the activity of the mantle plume triggered rifting associated with bimodal and alkaline granite magmatism. The formation of giant batholiths was typical of the evolution of the active continental margin of the Siberian paleocontinent in the Late Paleozoic and Early Mesozoic: the Khangai, Angara–Vitim, and Khentei batholiths were formed in this area within a relatively brief time span between 300 and 190Ma. The batholiths share certain features: they consist of granitoids of a broad compositional range, from tonalite and plagiogranite to granosyenite and rare-metal granites; and the batholiths were produced in relation to rifting processes that also formed rift magmatic zones in the surroundings of the batholiths. The large-scale and unusual batholith-forming processes are thought to have occurred when the active continental margin of the Late Paleozoic Siberian continent overlapped a number of hotspots in the Paleo- Asian Ocean. This resulted in the origin of a giant anorogenic magmatic province, which included batholiths, flood-basalt areas in Tarim and Junggar, and the Central Asian Rift System. The batholiths are structural elements of the latter and components of the zonal magmatic areas.
The output energy of 10.6 and 3.25 J with a pulse duration of ∼1 ms and a crystal temperature of 85 K was achieved in the Fe:ZnSe and Fe:ZnS lasers, respectively. At room temperature, the Fe:ZnSe ...laser energy was as high as 1.2 J with a pulse duration of 150 ns. A few optical schemas of the Cr:CdSe laser with laser diode pumping were realized.
Characteristics of an Fe:ZnSe laser with a new pump scheme were presented. An Fe:ZnSe crystal was placed inside the cavity of the Er:YLF laser pumped by a bar of laser diodes (LD) emitting at 975 nm. ...The high power 2.66 μm wave ~50 ns pulses were generated inside the cavity due to passive Q-switching of the Er:YLF laser by an Fe:ZnSe saturated absorber. These pulses pumped the Fe:ZnSe laser. As a result, the pulses with an energy of ~2 μJ at a wavelength around 4 μm and time duration of about 50 ns were generated. The laser operated in periodic-pulsed pump regime at room temperature with a repetition rate up to 200 Hz. The Q-switching pulse repetition rate during the pump pulse ran up to 2.5 kHz.
We report an investigation of a semiconductor disk laser (SDL) based on an InGaP/AlGaInP heterostructure emitting at a wavelength near 640 nm under in-well pumping by a pulsed rhodamine 6G dye laser ...with an emission wavelength of 601 nm. Use is made of structures with 25 quantum wells arranged in depth with a period of 193 nm. In a structure with a built-in Bragg mirror, a power of 3.5 W is reached at a wavelength of 642 nm with a slope efficiency of 7% with respect to the absorbed pump power. The achieved second harmonic power at a wavelength of 321 nm is approximately 30% of the maximum SDL power at the fundamental frequency. Under pumping above 250 W, the structure is destroyed due to strong adiabatic heating of the GaAs growth substrate. In a structure with a deposited broadband dielectric mirror, it is possible to reduce the adiabatic heating factor, implement double-pass pumping, and, accordingly, increase the supplied pump power. This makes it possible to obtain a pulse power of higher than 70 W at a wavelength of 645.5 nm with a slope efficiency of over 17%.
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