The use of static and dynamic light scattering (SLS and DLS, respectively) for chraracterization of solutions (0.005–0.20 mol·L− 1) of a series of carbohydrate-based low-molecular-mass compounds (glycosyl donors for chemical glycosylation) in anhydrous acetonitrile is described. The DLS data obtained suggest that, in the cases studied, the solute molecules form different supramolecular assemblies (supramers) with variable hydrodynamic radii. Analysis of concentration dependences of complementary SLS data for these solutions revealed that solvent quality may change dramatically with concentration and with the nature of solute. These results suggest that a combination of SLS and DLS is a valuable analytical tool for the supramer analysis of reaction solutions, which is useful for the rational selection of optimal concentrations for performing glycosylation reactions.

Hypothesis: Nanodiamonds, one of the most promising nanomaterials for the use in biomedicine, placed in the organisms are bound to interact with various amphiphilic lipids and their micelles. However, while the influence of surfactants, the close relative of lipids, on the properties of colloidal nanodiamonds is well studied, the influence of nanodiamonds on the properties of surfactants, lipids, and, therefore, on the structure of surrounding tissues, is poorly understood. Experiment: In this work, the influence of interactions of hydrophobic and hydrophilic nanodiamonds with ionic surfactant sodium octanoate in water on hydrogen bonds, the properties of the surfactant and micelle formation were studied using Raman spectroscopy and dynamic light scattering technique. Findings: Nanodiamonds are found to actively influence the bulk properties only of the premicellar surfactant solutions: the strength of hydrogen bonds, ordering and conformation of hydrocarbon tails, the critical micelle concentration. This influence is deduced to be dependent on two mechanisms not unique to nanodiamonds: (1) the induction of micro-flows around nanoparticles undergoing Brownian motions, and (2) the creation of the chaotic state in the surfactant solutions if two or more incompatible types of interactions between nanoparticles' surfaces and surfactants are similarly favorable, e.g. hydrophobic interaction and Coulomb attraction. (C) 2019 Elsevier Inc. All rights reserved.

A new glycosyl acceptor to be used in sialylation was designed as a 3-hydroxy derivative of 4-methoxyphenyl β-d-galactopyranoside with 2-O-acetyl group and O-4 and O-6 protected as benzylidene acetal. Two alternative syntheses of this compound were compared. Sialylation of 3-OH group of the glycosyl acceptor with O-chloroacetylated N-trifluoroacetylneuraminic acid phenyl thioglycoside (NIS, TfOH, MeCN, MS 3 Å, -40 °C) was studied in a wide concentration range (5-150 mmol L-1). The outcome of sialylation generally followed the predictions of supramer analysis of solutions of sialyl donor in MeCN, which was performed by polarimetry and static light scattering and revealed two concentration ranges differing in solution structure and the structures of supramers of glycosyl donor. The optimized conditions of sialylation (C = 50 mmol L-1) were used to synthesize protected Neu-α(2-3)-Gal disaccharide (78%, α:β = 13:1), which was then converted to sialyl-α(2-3)-galactose imidate building block useful for the synthesis of complex sialo-oligosaccharides.

Influence of nanodiamonds (ND) of 35 and 100 nm in size, containing NV centers, on the strength of hydrogen bonds under heating of the ND water suspensions in the range of 5–95 °C was studied by Raman spectroscopy. General tendency of both NDs to weaken hydrogen bonds in water was found. Substantial influence of functional state of ND surface on hydrogen bond strength was revealed. An influence of hydrogen bonds on fluorescence properties of the NDs in water suspensions was studied as well. It was found that fluorescence properties of NV centers of 100‐nm NDs are stable with regard to change of their surface state, whereas, a fluorescence intensity of the 35‐nm NDs essentially depends on strength of hydrogen bonds in the suspension.

Protein‐like and random NIPAM‐sodium styrene sulfonate copolymers of similar composition have been prepared by radical polymerization in water at temperatures above and below the LCST of PNIPAM, respectively. Thermal transitions of the copolymers in aqueous solutions have been studied by means of dynamic light scattering, viscometry, and high‐sensitivity differential scanning calorimetry. The phase separation or cooperative conformational transitions without phase separation were observed for the random or the protein‐like copolymers, respectively. Transition temperature, enthalpy, and heat capacity increment of the protein‐like copolymer differed insignificantly from those of the random copolymer of similar composition. The transition heat capacity increments of the protein‐like copolymers revealed that only 10–20% of their NIPAM links participate in the formation of a dense water‐free globule core. The coil–globule transitions of the protein‐like copolymers were described by the thermodynamic three‐state model according to the scheme “random coil↔condensed coil↔globule”, which is known to simulate the folding mechanism of globular proteins. image

Changes in the concentration of reagents (0.009–0.2 M ) have been shown to dramatically effect the yield and stereoselectivity of glycosylation with a sialic acid based glycosyl donor in a complex nonlinear manner that correlates with changes in the structures of the supramers of the reagents. The yield of disaccharide gradually increases with concentration and levels off at concentrations of glycosyl donor higher than 69 m M . The ratio of anomers is very high at some concentrations (α/β ≈ 20:1), moderate (α/β ≈ 8:1) or very low (α/β ≈ 4:1) at others. The formation of mixed supramers of glycosyl donor and glycosyl acceptor at concentrations exceeding 69 m M was detected by polarimetry and laser light scattering.

Third-harmonic generation is obtained for the 1245-nm laser radiation in monolayers of J-aggregates of a cyanine dye in a diallydimethylammonium chloride polymer matrix. The third-order susceptibility of J-aggregates is two orders of magnitude higher than that of fused silica. The wavelengths of fundamental and third-harmonic radiation lie in the transparency region of the material.

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ing researcher and teacher, Scientist of Merit of the Russian Federation, distinguished professor of the M V Lomonosov Moscow State University (MGU), honorary professor of the University of Chuvashia, died on March 1, 2000 at the age of 88. In his 70 years of work at the physics faculty of MGU, I A Yakovlev made a fundamental contribution to experimental research into piezoelectrics, ferroelectrics and semiconductors, and into the propagation of surface and pseudosurface elastic waves in solids. He wrote a number of textbooks that continue to be very useful to students and teachers. The lectures that Ivan Alekseevich read to students were wonderfully clear and profound. Ivan Alekseevich Yakovlev was born in Moscow on October 13, 1912. His grandfather, Ivan Yakovlevich Yakovlev, was a well-known Educator of the Chuvash People, who created the Chuvash alphabet and the written Chuvash language. Ivan Alekseevich's father, Alekse|̄ Ivanovich Yakovlev, was a student of professor Klyuchevski|̄ and continued his projects; he became a correspondingmember of the USSR Academy of Sciences. After graduating from school in 1929, Ivan Alekseevich entered the physicomathematical faculty of Moscow State University and graduated in 1932, after completing the courses ahead of the regular time. Yakovlev then worked for a year as assistant professor of the chair of physics at the Institute of Railway Transport Engineers and in 1934 transferred to the general physics chair in the physics faculty ofMoscow State University as assistant professor. From this time until his death Yakovlev's work was based in Moscow State University. From 1943 to 1946 I A Yakovlev was a postdoc at the Institute for Physical Problems of the USSR Academy of Sciences (currently the P L Kapitza Institute for Physical Problems of the Russian Academy of Sciences), working on his DSc thesis. He was able to show, from the study of light scattering in liquid helium, that in theHe I toHe II transition, the experimentally observed intensity of scattered light does not grow anomalously high, as was predicted by certain theories. Later Ivan Alekseevich studied electron scattering in metals and light absorption spectra in sapphire at low (liquid helium) temperatures. In 1942 IvanAlekseevich presented and defended his PhD thesis ``Studies of light scattering at low temperatures''. He defended his DSc thesis ``Studies of phase transitions of second kind in solids;'' in 1957. In 1959 he became an MGU professor. In 1974 he was elected to the Chair of crystal physics of the physics faculty, which he held for 15 years. Yakovlev's main research was carried out at the physics faculty of Moscow State University. At the beginning of the 1950s I A Yakovlev carried out experiments on the molecular scattering of light in crystals. Observations in quartz single crystals revealed for the first time in world physics that light scattering intensity in the a$ b phase transition in the 0:1 temperature interval was higher by four orders of magnitude than at room temperatures. He also studied light scattering in course of phase transitions in other crystals, e.g. ammonium chloride. His most significant results, also a world first, involve absorption of ultrasound in solids during phase transitions. Yakovlev discovered anomalous absorption of sound in potassium sodium tartrate crystals (Rochelle Salt) near the upper and lower Curie points. It was found that the position of the maximum of sound absorption on the temperature axis was independent of sound frequency. L D Landau gave a theoretical explanation of this anomaly and derived a formula for the sound absorption coefficient in ferroand nonferroelectrics. These results were generally recognized and generated a flux of similar studies in the world, and are widely cited. I A Yakovlev contributed much to the study of the spectrum of Mandelstam ±Brillouin scattering in piezoelectric semiconductors in an external DC field, when the acoustic Uspekhi Fizicheskikh Nauk 170 (5) 579 ± 580 (2000) Translated by V Kisin PERSONALIA PACS number: 01.60.+q