Effect of increasing pressure on the structure and temperature-induced changes in magnetic properties of heterospin complexes

Russian Chemical Bulletin - The study is concerned with structural rearrangements in the crystals of heterospin complexes Cu(hfac)2 with nitroxide radicals LR (hfac is hexafluoroacetylacetonate, LR...     

Extraction-chromatographic behavior of Zr(IV) and Hf(IV) on TRU and LN resins in mixtures of HNO3 and HF

The behavior of group-4 homologs Zr and Hf on extraction-chromatographic sorbents LN resin and TRU resin in mixtures of HF and HNO₃ is considered. Distribution coefficients of the elements in the mixtures of 5·10⁻⁴ M–1 M HF and 0.01 M–5 M HNO₃ are determined. Strong retention of both elements was found on LN resin in the range of concentrations c(HF) ≤ 0.01 M for all concentrations of HNO₃. Retention tends to gradually disappear while increasing c(HF) to 0.5 M. On TRU resin retention is observed only in solutions with c(HNO₃) ≥ 2 M and c(HF) ≤ 0.01 M. The possibility of separating Zr(IV) and Hf(IV) on LN resin is illustrated in two different acid mixtures, whereas their separation on TRU resin under the conditions studied in this work is difficult. The results obtained can be used to isolate analytes from multicomponent mixtures during analytical tasks, as well as to separate them from each other.

     

Stability of O3 + N2, O3 + O2 and O3 + CO2 double hydrates: DFT study

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Anti-neuraminidase activity of chemical constituents of Balanophora involucrata

Balanophora involucrata J. D. Hooker has been known to possess potential anti-inflammatory and antibacterial activities; however, its antiviral activity has not been evaluated so far. In order to find new neuraminidase inhibitors (NAIs), the neuraminidase (NA) inhibition activity of different B. involucrata extracts was evaluated. In this study, an in vitro NA inhibition assay was performed to identify which extract of B. involucrata exhibits (maximal) inhibitory activity against NA. Ultra high performance liquid chromatography/quadrupole time-of-flight–tandem mass spectroscopy (MS/MS) and molecular docking techniques were used to identify the specific compounds responsible for the anti-influenza activity of the extract, and to explore the potential natural NAIs. The ethyl acetate extract of B. involucrata exhibited significant inhibitory activity against NA with 50% inhibitory concentration (IC₅₀) value of 159.5 μg/mL. Twenty compounds were identified according to the MS/MS spectra; among them two compounds (quercitrin and phloridzin) showed obvious inhibitory activity against NA, with IC₅₀ of 311.76 and 347.32 μmol/L, respectively. This study suggested that B. involucrata can be a potential natural source of NAIs and may be useful in the fight against ferocious influenza viruses.     

Purcell Effect and Nonlinear Behavior of the Emission in a Periodic Structure Composed of InAs Monolayers Embedded in a GaAs Matrix

Enhancement of spontaneous emission in a resonant Bragg quantum well (QW) structure with 60 periods of triple InAs monolayers embedded in a GaAs matrix is studied experimentally and theoretically. From measurements of the time‐resolved photoluminescence, besides the QW exciton at 1.47 eV, a specific super‐radiant (SR) emission demonstrating nonlinear properties is found. The SR mode shows a near‐quadratic dependence of intensity on excitation power, while its energy position follows the Bragg condition. It is revealed that the SR mode shows a peculiar non‐monotonic dependence of intensity on direction, with a maximum observed at approximately 40°. The enhancement in the SR emission at a specific direction is correlated well with suggested theoretical consideration of the modal Purcell factor for periodic quantum well structures.     

Total Electron Content Measurements in the Ionosphere Disturbed by High-Power High-Frequency Waves by the Methods of Incoherent Scattering of Radio Waves and Radio Sounding by Glonass Satellite Signal

Radiophysics and Quantum Electronics - We present the results of comparing the total electron content measurements based on GLONASS satellite signals and the EISCAT UHF incoherent scatter radar...     

The visible and ultraviolet organic light-emitting diodes with germanium dioxide as facile solution-processed anode buffer layer

Germanium dioxide (GeO₂) aqueous solutions are facilely prepared and the corresponding anode buffer layers (ABLs) with solution process are demonstrated. Atomic force microscopy, X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy measurements show that solution-processed GeO₂ behaves superior film morphology and enhanced work function. Using GeO₂ as ABL of organic light-emitting diodes (OLEDs), the visible device with tris(8-hydroxy-quinolinato)aluminium as emitter gives maximum luminous efficiency of 6.5 cd/A and power efficiency of 3.5 lm/W, the ultraviolet device with 3-(4-biphenyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole as emitter exhibits short-wavelength emission with peak of 376 nm, full-width at half-maximum of 42 nm, maximum radiance of 3.36 mW/cm² and external quantum efficiency of 1.5%. The performances are almost comparable to the counterparts with poly (3,4-ethylenedioxythiophene):poly (styrenesulfonate) as ABL. The current, impedance, phase and capacitance as a function of voltage characteristics elucidate that the GeO₂ ABL formed from appropriate concentration of GeO₂ aqueous solution favors hole injection enhancement and accordingly promoting device performance.