Diels-Alder reaction between naphthalene and N-phenylmaleimide under mild conditions

The rate and equilibrium constants for the Diels-Alder reactions between benzene or naphthalene and several dienophiles at 25°C were calculated from the data on the ionization potentials of dienes and electron affinity energies of dienophiles, as well as the reaction enthalpies. The highest yield of the adduct was predicted for the reaction of naphthalene with N-phenylmaleimide. However, the time of its formation in 50% yield exceeds 30 years. The use of gallium chloride as a catalyst affords the endo-adduct for seven days at room temperature in 30% yield. The rate ((2±0.5)·10-6 L mol-1 s-1) and equilibrium constants (5±2 L mol-1) of the reaction were determined

Diffusion control of the Diels-Alder reaction rate at elevated pressures

The influence of the temperature and external pressure on the rate of the Diels-Alder reaction between 9,10-dimethylanthracene and maleic anhydride was studied in the series of solvents with wide intervals of viscosity (0.3-43.2 mPa s), dielectric constant (2-38), and internal pressure (3-8.8 kbar). At a standard pressure these properties of the solvent exert a weak and irregular effect on the reaction rate constant and activation enthalpy and entropy. The effect of the external pressure on the rate constant was studied in a high-pressure (up to 1 kbar) optical cell in acetonitrile and silicon oil and in a barostat cell (up to 6 kbar, toluene, silicon oil). Close values of the activation volume were obtained in all solvents. In toluene the reaction rate increases smoothly in the whole pressure interval. In more viscous silicon oil a similar dependence is observed up to 3 kbar, and the reaction rate decreases sharply with the further increase in the pressure and viscosity because of the diffusion control of the process

Volume parameters of some Diels - Alder reactions involving C=C, C=S, and N=N bonds

The effect of a hydrostatic pressure of up to 1000 kg cm-2 on the rate constants of the Diels - Alder reactions of maleic anhydride with 1,2,3,4-tetraphenylcyclopentadiene and with 6,13-dichloropentacene, of 4-phenyl-1,2,4-triazoline-3,5-dione with hexachlorocyclopentadiene, and of thiobenzophenone with isoprene was studied at 25°C. The volume parameters and ratios of the activation to reaction volumes make it possible to exclude electrostriction of the solvent during transition state solvation in all the reactions studied, which corresponds to the nonpolar nature of the transition state. © 2005 Springer Science+Business Media, Inc

Solvent effect on the heat of solution and partial molar volume of some non-electrolytes and lithium perchlorate

For several non-electrolytes and for lithium perchlorate the solvent effect on the heat of solution and partial molar volumes was studied. In the absence of the donor-acceptor and electrostatic interactions, clear proportionality can be seen only in the alkane solutions and these changes are defined by the non-alkane component. For solutions of π-acceptor (tetracyanoethylene) and v-acceptor (gallium chloride) in the presence of π,π-, π,V- and n,v-complexes, the relation between the changes of interaction energy and the values of the partial molar volumes can be seen. The maximum change in the value of partial molar volumes (up to 50cm mo1-1) was noted for lithium perchlorate in ten solvents. The volume change is proportional to the compressibility coefficients of the solvents and correlates less with the values of heat of solution and solvent permittivity. Copyright © 2006 John Wiley & Sons, Ltd

Dynamics of cognitive functions in treatment of alcohol-dependent patients

The article describes the results of dynamics of impaired cognitive functions of patients with alcohol dependence who received treatment with antipsychotics. Cognitive functions improve significantly faster in patients of the main group whose treatment included Risperidone, an atypical antipsychotic. There is insignificant positive dynamics of impaired cognitive functions in the group of patients who received Haloperidol as antipsychotic. The patients who received Risperidone have shown improved compliance, lack of negative attitude to the therapy provided as compared with the control group patients. Risperidone's most significant effects include improvement of disorganized psychic activity, recovery of active attention, dynamic and tempo parameters of activity, recovery of the capacity for unconditioned regulation of thinking and behavior, critical assessment

Comparative Analysis of NS5 Protein for Tick Borne Encephalitis Virus Strains in three Virus Subtypes

Non-structural protein 5 (NS5) of tick-borne encephalitis virus is an enzyme which is responsible for a copying of viral RNA, and it has a strong structural similarity to RNA polymerases of another RNA virus families. The strains of the virus are separated into three subtypes, which differ by specific mutations in virus proteins, including NS5 protein. The methods of structural bioinformatics allow to construct a model of NS5 protein for several strains of the virus.The paper presents the comparative analysis of sequences and structures of NS5 protein, for three subtypes of the tick-borne encephalitis virus. The segments of protein were identified where the highest difference between subtypes and within subtypes is observed. These segments, where most of the mutations are accumulated, are located in methyltransferase domain, in the inter-domain interface, and in the three subdomains of polymerase domain. The association between the locations of mutations in NS5 protein and the flexibility of a protein backbone was observed using normal mode analysis. Namely, the most important mutations are located in the parts of protein where the amplitude of synchronous oscillations estimated using normal mode analysis is the highest: in the second zinc binding pocket within polymerase domain, in the N-terminal extension within inter-domain interface, and around an active site of methyltransferase domain

Promising source material for winter triticale breeding under the conditions of the Middle Urals

Background. The northern border of cereal crop cultivation passes through the territory of Sverdlovsk Province. Cultivars of winter triticale developed in the regions of Russia located to the south are grown there, but they die under unfavorable winter conditions. The breeding of this crop in local climate is at an early stage, so a study of source material for breeding new highyielding cultivars adapted to local conditions seems quite pertinent.Materials and methods. In 2017–2020, the Ural Research Institute of Agriculture in Yekaterinburg conducted a study of 78 winter triticale genotypes from 10 regions of Russia and 7 foreign countries. The seeds were obtained from the VIR genebank and breeding centers of Russia. Sowing was carried out in clean fallow on August 20–25 on 1 m2 plots in 3-4 repetitions, with the reference ‘Bashkirskaya korotkostebelnaya’ sown on every 10th plot. Plants were assessed for winter hardiness, yield, density of productive stems, plant height, ear length, number of spikelets and grains per ear, weight of 1000 grains, and ear productivity in accordance with published guidelines.Results. Cvs. ‘Privada’, ‘Tsekad 90’ and ‘Nemchinovsky 58’ combined high winter hardiness (70–81%) with resistance to damage by snow mold (15–20%), high density of productive stems (324–425 pcs/m2), and high yield (562–616 g/m2). They had high 1000 grain weight (45.4–49.1 g) and ear productivity (2.63–2.68 g). High yield (571–670 g/m2) and density of productive stems (285–436 pcs/m2 ) with reduced winter hardiness (62–72%) and resistance to snow mold (30–35%) was observed in cvs. ‘Sirs 57’, ‘Sotnik’, ‘Germes’, ‘Antey’, ‘Beta’, ‘Don’, and lines 1/1 and 8003 from Sweden

Ионная проводимость и колебательные спектры сложных фосфатов в системе Li3PO4-Na3PO4-InPO4

Some properties of lithium-indium complex phosphates in the previously investigated Li3PO4-Na3PO4-InPO4 ternary system were studied. Ionic conductivity of isolated phases at 300ºC was measured. Vibration spectra of the investigated compounds were registered for 6Li → 7Li substituted samples from 1400 to 200 cm-1 frequency range. Isotope shifts under 6Li → 7Li substitution were observed for all the complex phosphates. The obtained results allowed to reveal intrinsic lithium sublattice vibration and to relate complex phosphates structure to ionic conductivity magnitude.Изучены некоторые свойства сложных фосфатов лития и индия, выделенных в ранее исследованной системе Li3PO4-Na3PO4-InPO4. Определена ионная проводимость выделенных фаз при 300ºC. Kолебательные спектры исследуемых соединений были зарегистрированы для 6Li → 7Li изотопозамещенных образцов, в частотном диапазоне от 1400 до 200 см-1. Изотопные сдвиги частот отмечены для каждого исследуемого сложного фосфата, что позволило выявить собственные колебания подрешетки лития и установить взаимосвязь между структурой сложных фосфатов и величиной ионной проводимости

Diels-Alder reaction between naphthalene and N-phenylmaleimide under ambient and high pressure conditions

The rate and equilibrium constants for the Diels-Alder reactions between benzene and naphthalene as dienes and tetracyanoethylene, maleic anhydride and N-phenylmaleimide as dienophiles at 25°C were estimated from empirical rule. The highest yield of the adduct was predicted for the reaction of naphthalene with N-phenylmaleimide. The time of adduct formation in 50% yield exceeds 30 years. The use of gallium chloride as a catalyst affords the exo-adduct for seven days at room temperature. The rate ((2±0.5)•10-6 L mol-1 s-1) and equilibrium constants (5±2 L mol-1) of this reaction were determined. Under high pressure conditions (8kbar) reaction occurs with formation of both stereo isomers at 100°C during 80 hours. © ARKAT

Multimodal optical measurement for study of lower limb tissue viability in patients with diabetes mellitus

According to the International Diabetes Federation, the challenge of early stage diagnosis and treatment effectiveness monitoring in diabetes is currently one of the highest priorities in modern healthcare. The potential of combined measurements of skin fluorescence and blood perfusion by the laser Doppler flowmetry method in diagnostics of low limb diabetes complications was evaluated. Using Monte Carlo probabilistic modeling, the diagnostic volume and depth of the diagnosis were evaluated. The experimental study involved 76 patients with type 2 diabetes mellitus. These patients were divided into two groups depending on the degree of complications. The control group consisted of 48 healthy volunteers. The local thermal stimulation was selected as a stimulus on the blood microcirculation system. The experimental studies have shown that diabetic patients have elevated values of normalized fluorescence amplitudes, as well as a lower perfusion response to local heating. In the group of people with diabetes with trophic ulcers, these parameters also significantly differ from the control and diabetes only groups. Thus, the intensity of skin fluorescence and level of tissue blood perfusion can act as markers for various degrees of complications from the beginning of diabetes to the formation of trophic ulcers