Synthesis and Study of Antimicrobial Activity of Water-Soluble Ammonium Acylhydrazones Based on New 1,ω-Alkylenebis(isatins)

Russian Journal of General Chemistry - Alkylation of isatin with 1,ω-dihaloalkanes afforded bis(heterocycles) connected by an oligomethylene linker. The reaction of the resulting bis(isatins)...     

Origin of Rayleigh scattering and anomaly of elastic properties in vitreous and molten GeO2

Vitreous (v) and molten (m) GeO₂ were studied by Rayleigh and Mandel’shtam–Brillouin scattering spectroscopy and high-temperature acoustics. Original measurement apparatus and procedure were used that included Bayseian deconvolution of light scattering spectra of vGeO₂ and a specially designed high-temperature (up to 1500 °C) acoustic interferometer to measure temperature and frequency dependence of ultrasonic (US) velocity and attenuation in mGeO₂. Landau–Placzek ratios for vGeO₂ were found optically (from the light scattering spectrum) and acoustically (through the Schroeder’s formalism). Dispersion of optical and other physical parameters of vGeO₂ found by many authors is explained by the existence of small amount of GeO in the samples. It means that properties of vGeO₂ are under the influence of redox synthesis conditions controlling the GeO₂ ↔ GeO and coordination [GeO₄] ↔ [GeO₆] equilibrium in vGeO₂. Measurements of temperature dependencies of longitudinal ultrasonic velocities in mGeO₂ and in the PbO–GeO₂ glass melts as a function of PbO concentration shows existence of ‘water-like anomaly’ in mGeO₂ and in liquid germanates with the rich content of GeO₂ where equilibrium sound velocity increases with the temperature.     

Processes of Aggregation of Fullerene C60 in Polymer–Fullerene Composites

Physics of the Solid State - The results of studying the absorption spectra of C60 polymer–fullerene composites are presented. In the composite polymethylmethacrylate–C60, a gradual...     

Restoration of parameters of high-energy cascades in Cherenkov water calorimeter with a dense array of quasispherical modules

A problem concerning the restoration of the parameters of a cascade shower with an unknown axis originating by muons in a Cherenkov water calorimeter is considered. A method for estimating the direction and geometric position of the cascade’s axis, which is based on the analysis of responses of quasispherical modules, and the criteria of selection of the events with cascades among the events with a large energy liberation are proposed. The method and the criteria are tested on events with cascades generated by near-horizontal muons of high energies detected by a DECOR coordinate-track detector. The preliminary results of measurements of the energy spectrum of cascade showers are presented.     

Isolation of oxidative degradation products of atorvastatin with supercritical fluid chromatography

The isolation of four oxidative degradation products of atorvastatin using preparative high‐performance liquid chromatography applying at least two chromatographic steps is known from the literature. In this paper it is shown that the same four impurities could be isolated from similarly prepared mixtures in only one step using supercritical fluid chromatography. The methods for separation were developed and optimized. The preparation of the mixtures was altered in such a way as to enhance the concentration of desired impurities. Appropriate solvents were applied for collection of separated impurities in order to prevent degradation. The structures of the isolated impurities were confirmed and their purity determined. The preparative supercritical fluid chromatography has proven to be superior to preparative HPLC regarding achieved purity of standards applying fewer chromatographic as well as isolation steps. Copyright © 2015 John Wiley & Sons, Ltd.     

Effect of the Cationic Moiety on the Antimicrobial Activity of Sterically Hindered Isatin 3-Hydrazone Derivatives

Russian Journal of Organic Chemistry - Water-soluble 1-(3,5-di-tert-butyl-4-hydroxybenzyl)isatin 3-acylhydrazones containing an acyclic, bicyclic, or pyridinium quaternary ammonium center in the...     

Data Acquisition and Diagnostic System for Prototype of PANDA Pellet Target

Physics of Atomic Nuclei - In the PANDA experiment of the FAIR project, it is proposed to use internal targets based on the hydrogen isotopes that provide a monodisperse regime of flow generation...     

Thermal Pretreatment of Harvest Residues and Their Use in Anaerobic Co-digestion with Dairy Cow Manure

Several batch experiments were conducted on the anaerobic co-digestion of dairy cow manure (DCM) with three harvest residues (HR) (soybean straw, sunflower stalks, and corn stover). The influence of thermal pretreatment of HR on biogas production was investigated, where the HR were thermally pretreated at two different temperatures: T = 121 °C and T = 175 °C, during t = 30 and t = 90 min, respectively. All anaerobic co-digestion batch experiments were performed simultaneously under thermophilic regime, at T = 55 °C. Biogas and methane yields were significantly improved in experiments performed with corn stover thermally pretreated at 175 °C for 30 min (491.37 cm³/g VS and 306.96 cm³/g VS, respectively), if compared to experiments performed with untreated corn stover. The highest VS and COD removal rates were also observed in the same group of experiments and were 34.5 and 50.1%, respectively. The highest biogas and methane yields with soybean straw (418.93 cm³/g VS and 261.44 cm³/g VS, respectively) were obtained when soybean straw pretreated at 121 °C during 90 min. The highest biogas and methane yields with sunflower stalk (393.28 cm³/g VS and 245.02 cm³/g VS, respectively) were obtained when sunflower stalk was pretreated at 121 °C during 90 min.     

Electronic structure study of thermal intraconversions of some dicyclopenta-fused polycyclic aromatic compounds

The electronic structure of dicyclopenta[de,mn]anthracene (P1), dicyclopenta[ de,kl]anthracene (P2), and dicyclopenta[jk,mn]phenanthrene (P3) and their mutual isomerization processes are investigated using density functional theory. Two mechanisms for the thermal intraconversion of P1 to P2 were found. The first mechanism occurs via ethynylaceanthrylene (I0), and the second involves a 1,2-hydrogen shift. It is supposed that I0 is initially formed during the flash vacuum pyrolysis experiments, eventually rearranging to P2 on high temperatures. The energetics of the latter mechanism also indicate that P1 isomerizes to P2. The mechanism for a transformation of P2 to P3 is based on a ring contraction/ring conversion process and requires extremely high temperatures. Our investigation is in accord with the experimental results: unsuccessful synthesis of P1, stability of P2 at high temperature, and formation of P3 under extreme temperature regime.     

Synthesis of new nucleoside analogs containing amino bisphosphonic groups

Adenosine derivatives containing a 2,2-bis(diethoxyphosphoryl)ethyl or 2,2-diphosphonoethyl group on the amino nitrogen atom were synthesized for the first time by reaction of 5′-chloro-5′-deoxy- and 5′-hydroxy-2′,3′-isopropylideneadenosine with tetraethyl ethene-1,1-diylbis(phosphonate) or tetrakis(trimethylsilyl) ethene-1,1-diylbis(phosphonate).