Humic-based bionanocomposites containing stable paramagnetic gold nanoparticles for prospective use in pharmaceuticals

Structural peculiarities and supramolecular organization of medicinally promising nanocomposites, synthesized from humic substances, which essentially differ depending on decomposition degree, have been studied using electron spin resonance, transmission electron, and confocal laser scanning microscopy techniques and some other modern physical–chemical methods. It is shown that stable zero-valent gold nanoparticle of about 10–17?nm in size are formed in a natural macromolecular matrix. The nanocomposites obtained turn out to be stable in aggregative state for a long time and preserve their properties that are extremely important for prospective medicinal substances.     

Effect of supramolecular interactions with cationic surfactants on adsorption of flavonoids on highly dispersed silica surface

The effect of the cationic surfactants decamethoxine and miramistin on the physicochemical properties of the natural flavonoids quercetin and rutin is studied spectrophotometrically in the range of physiological pH values. It is established that the interaction with these cationic surfactants changes the spectral characteristics of the flavonoids in solutions and essentially increases their adsorption on the surface of highly dispersed silica as compared with their aqueous solutions. It is shown that the efficiency of flavonoid adsorption from decamethoxine and miramistin solutions is governed by solution pH, flavonoid hydrophobicity, and the nature of a cationic surfactant.     

The preparation and properties of “porous silicon–nickel ferrite” nanoheterocomposites for gas detectors

This paper discusses the preparation and properties of gas detectors based on “porous silicon–nickel ferrite” nanocomposites. Impedance spectroscopy was used to measure sensitivity to ethanol and isopropanol vapours in the presence of an alternating electric field. The results were interpreted with the help of an equivalent electrical circuit. In the analysis of the resistive–capacitive properties in the equivalent circuit a constant phase element was used.     

Band structure and broadband compensation of absorption by amplification in layered optical metamaterials

The frequency dependence of the gain required to compensate for absorption is determined for a layered structure consisting of alternating absorbing and amplifying layers. It is shown that the fulfillment of the same conditions is required for the existence of a band structure consisting of alternating bands allowed and forbidden for optical radiation propagation in the frequency-wave vector parametric region. Conditions are found under which the gain required for compensation is smaller than thresholds for absolute (parasitic lasing) and convective (waveguide amplification of radiation) instabilities.     

Fluorescence induced by double K capture

Features of double fluorescence spectra generated by double K capture in the ⁷⁸Kr atom are considered. The energies and bandwidths of fluorescence are calculated. The latter are approximately four times wider for the first and second quanta, respectively, relative to the vacancy hole in the K shell. The fluorescence yields are calculated as well. They are 0.77 and 0.61 for the first and second quanta, respectively, and 0.47 for both quanta simultaneously.     

Complexation and flotation of nonferrous metal ions from alkaline solutions with N-acyl-N′-(p-toluenesulfonyl)hydrazines

Surfactant properties and complexation conditions of Cu(II), Co(II), Ni(II), Zn(II), and Cd(II) ions in alkaline media with N-acyl-N′-(p-toluenesulfonyl)hydrazines, which enable their use in ion flotation processes, were studied. The efficiency of the compounds under study as collectors in aftertreatment of alkaline wastewater to remove milligram amounts of Cu(II) and other metals by ion flotation was demonstrated.