Microphase Separation within a Comb Copolymer with Attractive Side Chains: A Computer Simulation Study

Computer simulation modelling of a flexible comb copolymer with attractive interactions between the monomer units of the side chains is performed. The conditions for the coil-globule transition, induced by the increase of attractive interaction, ε, between side chain monomer units, are analysed for different values of the number of monomer units in the backbone, N, in the side chains, n, and between successive grafting points, m. It is shown that the coil-globule transition of such a copolymer corresponds to a first-order phase transition. The energy of attraction (ε) required for the realisation of the coil-globule transition decreases with increasing n and decreasing m. The coil-globule transition is accompanied by significant aggregation of side chain units. The resulting globule has a complex structure. In the case of a relatively short backbone (small value of N), the globule consists of a spherical core formed by side chains and an enveloping shell formed by the monomer units of the backbone. In the case of long copolymers (large value of N), the side chains form several spherical micelles while the backbone is wrapped on the surfaces of these micelles and between them.

Фармакокинетические исследования лекарственной формы нового стимулятора когнитивных функций мозга OSPL-502

The main pharmacokinetic parameters of a new stimulator of cognitive brain functions, OSPL – 502 have been determined: area under the concentration-time curve, elimination rate constant, half-elimination period, time to reach the maximum concentration, maximum concentration, volume distribution, total clearance and bioavailability of the dosage form. The main metabolites of the active substance of the dosage form of the new stimulator of cognitive functions OSPL – 502 have been analyzed. The data obtained predict the effects of the drug in humans relevant for further clinical investigation.Проведенное исследование фармакокинетических параметров лекарственной формы нового стимулятора когнитивных функций мозга OSPL-502 позволило определить основные фармакокинетические параметры (площадь под кривой “концентрация-время”; константа скорости элиминации; период полуэлиминации; время достижения максимальной концентрации; максимальная концентрация; объём распределения; общий клиренс). Определена биодоступность лекарственной формы. Проанализированы основные метаболиты действующего вещества лекарственной формы нового стимулятора когнитивных функций мозга OSPL-502. Полученные данные позволят спрогнозировать действие препарата у человека для дальнейшего клинического исследования

Measurements of Ξ(1530)0{\Xi \left( 1530\right) ^{0}} and Ξ‾(1530)0{\overline{\Xi }\left( 1530\right) ^{0}} production in proton–proton interactions at sNN\sqrt{s_{NN}} = 17.3 = 17.3 GeV \text{ GeV } in the NA61/SHINE experiment

Double-differential yields of $\Xi\left(1530\right)^{0}$ and $\overline{\Xi}\left(1530\right)^{0}$ resonances produced in \pp interactions were measured at a laboratory beam momentum of 158~\GeVc. This measurement is the first of its kind in \pp interactions below LHC energies. It was performed at the CERN SPS by the \NASixtyOne collaboration. Double-differential distributions in rapidity and transverse momentum were obtained from a sample of 26$\cdot$10$^6$ inelastic events. The spectra are extrapolated to full phase space resulting in mean multiplicity of $\Xi\left(1530\right)^{0}$ (6.73 $\pm$ 0.25 $\pm$ 0.67)$\times10^{-4}$ and $\overline{\Xi}\left(1530\right)^{0}$ (2.71 $\pm$ 0.18 $\pm$ 0.18)$\times10^{-4}$. The rapidity and transverse momentum spectra and mean multiplicities were compared to predictions of string-hadronic and statistical model calculations

Measurements of Ξ−{\Xi }{^-} and Ξ‾+\overline{\Xi }{^+} production in proton–proton interactions at sNN\sqrt{s_{NN}}=17.3 GeV = 17.3 GeV in the NA61/SHINE experiment

International audienceThe production of $\Xi (1321)^{-}$ and $\overline{\Xi }(1321)^{+}$ hyperons in inelastic p+p interactions is studied in a fixed target experiment at a beam momentum of 158 $\hbox {Ge}\hbox {V}\!/\!c$. Double differential distributions in rapidity ${y}$ and transverse momentum $p_{T}$ are obtained from a sample of 33M inelastic events. They allow to extrapolate the spectra to full phase space and to determine the mean multiplicity of both ${\Xi }{^-}$ and $\overline{\Xi }{^+}$. The rapidity and transverse momentum spectra are compared to transport model predictions. The ${\Xi }{^-}$ mean multiplicity in inelastic p+p interactions at 158 $\hbox {Ge}\hbox {V}\!/\!c$ is used to quantify the strangeness enhancement in A+A collisions at the same centre-of-mass energy per nucleon pair

Open charm measurements in NA61/SHINE at CERN SPS

The measurements of open charm production was proposed as an important tool to investigate the properties of the hot and dense matter formed in nucleus-nucleus collisions as well as to provide the means for model independent interpretation of the existing data on J/ψ suppression. Recently, the experimental setup of the NA61/SHINE experiment was supplemented with a Vertex Detector which was motivated by the importance and the possibility of the first direct measurements of open charm meson production in heavy ion collisions at SPS energies. First test data taken in December 2016 on Pb+Pb collisions at 150A GeV/c allowed to validate the general concept of D0 meson detection via its D0 → π+ + K− decay channel and delivered a first indication of open charm production. The physics motivation of open charm measurements at SPS energies, pilot results on open charm production, and finally, the future plans of open charm measurements in the NA61/SHINE experiment after LS2 are presented

Diagrams of the Lamellar Liquid Crystal Phase in Systems Based on n-Alkyl-poly (ethylene) Glycols (C<inf>8</inf>E<inf>5</inf> and C<inf>12</inf>E<inf>5</inf>) and n-Octanol Determined by ¹H NMR Spectroscopy

© 2020, Springer Science+Business Media, LLC, part of Springer Nature. The two lyotropic liquid crystalline media based on n-alkyl-poly (ethylene) glycols (C8E5 and C12E5) and n-octanol for partial alignment of organic molecules and measured residual constants of dipole-dipole interaction between magnetic nuclei were studied. The paper presents the results of NMR studies of lyotropic properties of considered liquid crystalline media, and the boundaries (diagrams) of the existence of ordered lamellar phases (component concentrations, solution temperature) were determined

Phase diagrams of new lamellar liquid crystalline systems based on ²H NMR spectroscopy data

Lyotropic liquid crystals based on cetylpyridinium chloride (or bromide) and n-hexanol were examined by NMR spectroscopy. The partial molecule ordering, residual dipolar couplings as well as the conditions (component concentrations and temperatures) under which lamellar phases exist were determined

The spatial structure of macroheterocyclic compounds, as a key factor affecting the course of the macrocyclization reaction

© ISUCT Publishing. Nowadays the macrocyclization reaction is often used for the synthesis of new macroheterocyclic compounds. This is a one-pot reaction, carried out in one stage, which makes it the most convenient and efficient in the synthesis of complex macroheterocyclic compounds. One of the key parameters in the selection of synthesis conditions is the spatial structure and conformational composition of the synthesized compounds. The fact is that if the certain structure prevails in the solution, then it is the most energetically favorable, i.e. its potential energy is minimal and therefore it is necessary to spend less energy to synthesis of this compound. The structure, obtained during the synthesis process, largely depends on what solvent is used. In this work, it was shown that the conformational composition of the macroheterocyclic model compound in various solvents differs by 10-20 %. This fact must be taken into account when conducting macrocyclization reactions not only for the model compound presented in this paper, but also for other substances consisting of macroheterocyclic molecules, such as crown ethers, cyclosporine, calixarenes, and other classes of compounds having a non-rigid structure

NMR chemical shifts of carbon atoms and characteristic shift ranges in the oil sample

Application of high resolution 13C nuclear magnetic resonance (NMR) spectroscopy to characterize crude oil was demonstrated. The chemical shifts of 13C NMR functional groups that determine the composition of the oil sample were determined. Molar fractions of primary, secondary, quaternary, tertiary, aromatic groups, aromatic factor and average hydrocarbon chain length of aliphatic hydrocarbons of the oil sample according to 13C NMR spectra were determined. Detailed description of the 13C NMR spectra of the oil sample using a single consideration of three NMR spectra: 13C, 13C Attached Proton Test (APT), 13C with Gated Decoupling (GD) was performed. The different contribution of the studied oil sample in the aliphatic (10–75 ppm) and aromatic (115–165 ppm) areas of the 13C NMR spectra was determined. The presence of all major hydrocarbon components in the studied oil sample was established on the quantitative level, the aromaticity factor and the mean length of the hydrocarbon chain were evaluated. Quantitative fractions of aromatic molecules and functional groups constituting oil hydrocarbons were determined. In this work we demonstrate that the attached proton test and gated decoupling 13C NMR spectroscopy can afford all information to complete the chemical shift assignment of an oil sample, especially for determination of long range 1H–13C coupling constants and 13C multiplicity