Continuous observations of the surface energy budget and meteorology over the Arctic sea ice during MOSAiC.

The Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) was a yearlong expedition supported by the icebreaker R/V Polarstern, following the Transpolar Drift from October 2019 to October 2020. The campaign documented an annual cycle of physical, biological, and chemical processes impacting the atmosphere-ice-ocean system. Of central importance were measurements of the thermodynamic and dynamic evolution of the sea ice. A multi-agency international team led by the University of Colorado/CIRES and NOAA-PSL observed meteorology and surface-atmosphere energy exchanges, including radiation; turbulent momentum flux; turbulent latent and sensible heat flux; and snow conductive flux. There were four stations on the ice, a 10 m micrometeorological tower paired with a 23/30 m mast and radiation station and three autonomous Atmospheric Surface Flux Stations. Collectively, the four stations acquired ~928 days of data. This manuscript documents the acquisition and post-processing of those measurements and provides a guide for researchers to access and use the data products.

Strain-Tuned Spin-Wave Interference in Micro- and Nanoscale Magnonic Interferometers.

Here, we report on the experimental study of spin-wave propagation and interaction in the double-branched Mach-Zehnder interferometer (MZI) scheme. We show that the use of a piezoelectric plate (PP) with separated electrodes connected to each branch of the MZI leads to the tunable interference of the spin-wave signal at the output section. Using a finite element method, we carry out a physical investigation of the mechanisms of the impact of distributed deformations on the magnetic properties of YIG film. Micromagnetic simulations and finite-element modelling can explain the evolution of spin-wave interference patterns under strain induced via the application of an electric field to PP electrodes. We show how the multimode regime of spin-wave propagation is used in the interferometry scheme and how scaling to the nanometer size represents an important step towards a single-mode regime. Our findings provide a simple solution for the creation of tunable spin-wave interferometers for the magnonic logic paradigm.

Hydrophobic Modification of Chitosan via Reactive Solvent-Free Extrusion.

Hydrophobic derivatives of polysaccharides possess an amphiphilic behavior and are widely used as rheological modifiers, selective sorbents, and stabilizers for compositions intended for various applications. In this work, we studied the mechanochemical reactions of chitosan alkylation when interacting with docosylglycidyl and hexadecylglycidyl ethers in the absence of solvents at shear deformation in a pilot twin-screw extruder. The chemical structure and physical properties of the obtained derivatives were characterized by elemental analysis, FT-IR spectroscopy, dynamic light scattering, scanning electron microscopy, and mechanical tests. According to calculations for products soluble in aqueous media, it was possible to introduce about 5-12 hydrophobic fragments per chitosan macromolecule with a degree of polymerization of 500-2000. The length of the carbon chain of the alkyl substituent significantly affects its reactivity under the chosen conditions of mechanochemical synthesis. It was shown that modification disturbs the packing ability of the macromolecules, resulting in an increase of plasticity and drop in the elastic modulus of the film made from the hydrophobically modified chitosan samples.

Solvent-free synthesis and characterization of allyl chitosan derivatives.

The solvent-free synthesis of allyl-substituted chitosan derivatives through reactive co-extrusion of chitosan powder with allyl bromide at shear deformation was performed. For the structural characterization, FTIR and NMR methods were employed. The results were confirmed by chemical analysis. The total content of allyl substituents from 5 to 50 per 100 chitosan units as a function of the component ratio in the reactive mixtures was revealed. Carrying out the reaction without any additives leads to the selective formation of N-alkylated derivatives, whereas in the presence of alkali the ethers of chitosan were preferentially formed. The results suggest that the proposed approach allows significantly higher yield of products to be obtained at high process speeds and significantly lower reagent consumption as compared with the liquid-phase synthesis in organic medium. The synthesized unsaturated derivatives are promising photosensitive components for use in laser stereolithography for fabrication of three-dimensional biocompatible structures with well-defined architectonics.

Two-Photon-Induced Microstereolithography of Chitosan-g-Oligolactides as a Function of Their Stereochemical Composition.

Chitosan-g-oligolactide copolymers with relatively long oligolactide grafted chains of various stereochemical compositions have been synthetized via a solvent-free mechanochemical technique and tailored to fabricate three-dimensional hydrogels using two-photon induced microstereolithography. An effect of the characteristics of chitosan and oligolactide used for the synthesis on the grafting yield and copolymer's behavior were evaluated using fractional analysis, FTIR-spectroscopy, dynamic light scattering, and UV-spectrophotometry. The lowest copolymer yield was found for the system based on chitosan with higher molecular weight, while the samples consisting of low-molecular weight chitosan showed higher grafting degrees, which were comparable in both the cases of l,l- or l,d-oligolactide grafting. The copolymer processability in the course of two-photon stereolithography was evaluated as a function of the copolymer's characteristics and stereolithography conditions. The structure and mechanical properties of the model film samples and fabricated 3D hydrogels were studied using optical and scanning electron microscopy, as well as by using tensile and nanoindenter devices. The application of copolymer with oligo(l,d-lactide) side chains led to higher processability during two-photon stereolithography in terms of the response to the laser beam, reproduction of the digital model, and the mechanical properties of the fabricated hydrogels.

The frequency of CYP2C9, VKORC1, and CYP4F2 polymorphisms in Russian patients with high thrombotic risk.

BACKGROUND AND OBJECTIVE: VKORC1, CYP2C9, and CYP4F2 are known to be responsible for the metabolism of warfarin. The aim was to explore the frequencies of these genotypes in the Russian population and compare the results with those for other populations. MATERIAL AND METHODS: In total, 91 Caucasian subjects with a mean age of 66.17 years (SD, 10.9) were recruited into the study. Of them, 40 patients (48.2%) were men. In order to obtain necessary clinical data, the medical records of the patients were reviewed. Blood (5 mL) was taken from each subject, and DNA was isolated and used for identification of the CYP2C9 allele *1, *2, *3, -1639G/A VKORC1, and CYP4F2 V433M rs2108622 C>T, using the real-time polymerase chain reaction-restriction fragment length polymorphism assay. RESULTS: The CYP2C9*1/*1 genotype was detected in 67.0%, CYP2C9*1/*2 in 9.9%, CYP2C9*1/*3 in 11.0%, CYP2C9*2/*2 in 2.2%, CYP2C9*2/*3 in 8.8%, and CYP2C9*3/*3 in 1.1% of the patients. The results for VKORC1 were as follows: 49.5% (GG), 28.6% (GA), and 22.0% (AA); meanwhile, those for the genotype CYP4F2 were 57.1% (CC), 34.1% (CT), and 7.7% (TT). No significant deviations from the Hardy-Weinberg equilibrium were observed. The frequency of the polymorphisms in the Russian population was found to differ from Asian and close to Caucasian. There were no significant interethnic variations in the frequency of CYP4F2 among Russian, Asian, and Caucasian populations. CONCLUSION: The frequency of CYP2C9, CYP4F2, and VKORC1 polymorphisms in Russian patients is comparable with other European ethnic groups.