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The study investigates the kinetics and thermodynamics of the reversible tandem Diels–Alder (tDA) reaction between difuranic compounds and maleimides, leading to the quantitative formation of tDA adducts at rates comparable to their counterparts from the "classical" Diels–Alder (DA) reaction. The tDA adducts exhibited unprecedented thermal stability up to 250 °C, which is 100 °C higher than that of the DA adducts, owing to the higher activation energy (Ea) required for the initial intramolecular step of the reverse process. The stability of the tDA adducts was exploited in the AA + BB type polymerization of tetrafuranic monomers with bis(maleimides), yielding thermally stable (up to 200 °C) yet depolymerasable linear polymers with molecular weights of 10–20 kDa. Only furanic groups were identified as the end-groups of the resulting polymers, suggesting the possibility for post-polymerization and end-group modifications. NMR and GPC kinetic data offered insights into the intermediate formation of classical adducts during polymerization, as well as the stereochemistry of tDA adducts in the polymer chains. Combined thermal analysis (DSC, TGA, and TMA) provided a comprehensive understanding of the reverse DA reaction in the resulting materials. This relatively clean, catalyst- and byproduct-free, well-controlled process, which uses derivatives of biorenewables as monomers, heralds the formation of a new class of thermally recyclable polymers. [ABSTRACT FROM AUTHOR]

Internal dynamics and kinematics of galaxies have imprints on the line-of-sight velocity distribution (LOSVD). Gauss–Hermite parametrization allows one to identify the kinematics features of the system in terms of skewness (h 3) and broadness (h 4) deviations of an LOSVD. Such a method provides information about the type of orbits since a |$h_3\!-\!\overline{V}$| correlation is a sign of elongated orbits, and the anticorrelation is a sign of circular or near-circular orbits. In previous works, analysis of the |$h_3\!-\!\overline{V}$| relation provided a tool to identify a hidden bar or B/PS bulge (edge-on, PA = 90°) and to probe their strength. We prepared two N -body galaxy models with clear B/PS bulges: one has an ordinary bar (the X model), and the second one has a barlens embedded into a bar (the BL model) to investigate the mechanism of formation of h 3 features at any position of an observer. We show that the |$h_3\!-\!\overline{V}$| correlation appears in the regions where bar and disc particles are mixing. We also reveal that the model with a barlens has an |$h_3\!-\!\overline{V}$| anticorrelation in the centre, and we show that barlens-specific orbits are responsible for this signal. Moreover, this feature can be observed only for galaxies with compact bulges and barlenses. The results of this work are applicable for the interpretation of future integral-field unit (IFU) data for real galaxies with B/PS bulges, especially for objects with barlenses. [ABSTRACT FROM AUTHOR]

A significant part of barred disc galaxies exhibits boxy/peanut-shaped structures (B/PS bulges) at high inclinations. Another structure also associated with the bar is a barlens, often observed in galaxies in a position close to face-on. At this viewing angle, special kinematic tests are required to detect a 3D extension of the bars in the vertical direction (B/PS bulges). We use four pure N -body models of galaxies with B/PS bulges, which have different bar morphology from bars with barlenses to the so-called face-on peanut bars. We analyse the kinematics of our models to establish how the structural features of B/PS bulges manifest themselves in the kinematics for galaxies at intermediate inclinations and whether these features are related to the barlenses. We apply the dissection of the bar into different orbital groups to determine which of them are responsible for the features of the LOSVD (line-of-sight velocity distribution), i.e. for the deep minima of the h 4 parameter along the major axis of the bar. As a result, we claim that for our models at the face-on position, the kinematic signatures of a 'peanut' indeed track the vertical density distribution features. We conclude that orbits responsible for such kinematic signatures differ from model to model. We pay special attention to the barlens model. We show that orbits assembled into barlens are not responsible for the kinematic signatures of B/PS bulges. The results presented in this work are applicable to the interpretation of IFU observations of real galaxies. [ABSTRACT FROM AUTHOR]

We draw attention to the bright galaxies that do not show a bar in their structure but have a flocculent spiral structure. Using the THINGS and HERACLES kinematic data for four barless galaxies (NGC 2841, NGC 3512, NGC 5055, NGC 7331), we built their mass models including dark haloes. We concluded that the fraction of the dark matter does not exceed 50 per cent within the optical radii of the galaxies. This is too little to explain the lack of a bar in these galaxies. In an attempt to understand the featureless structure of these galaxies, we constructed several N -body models with an initially reduced content of dark matter. We concluded that, in addition to the low mass of the dark halo, the decisive factor that leads to a barless disc is the start from an initially unstable state. An isolated dynamically cold disc (with the Toomre parameter Q < 0.5) settled into rotational equilibrium passes through the short stage of violent instability with fragmentation and formation of stellar clumps. After that, it evolves passively and ends up with a featureless structure. We assume that the barless flocculent galaxies studied in this work may be descendants of galaxies at high redshifts with rotation curves that are consistent with the high mass fraction of baryons relative to the total dark matter halo. [ABSTRACT FROM AUTHOR]

The article deals with the issue of efficient processing of local plant materials. The possibility of using the pulp of Michurinskaya pumpkin grown in Belgorod region for producing candied fruit is discussed. The product is characterized by high organoleptic characteristics. Results of the physical and chemical studies and microbiological analysis are consistent with the standardized indicators. The functional properties of the candied fruit were identified and described.

We present the biggest up-to-date sample of edge-on galaxies with boxy/peanut-shaped (B/PS) bulges and X-structures. The sample was prepared using images from the Dark Energy Spectroscopic Instrument (DESI) Legacy catalogue and contains about 2000 galaxies. To find suitable candidates in catalogue, we made the assumption that the residues (original images minus model) of galaxies with B/PS bulges should exhibit a characteristic X-shape. Galaxies with such features were selected by eye and then used as input data for a neural network training, which was applied to a bigger sample of edge-on galaxies. Using the available data and the photometric models from the literature, we investigated the observational and statistical properties of the sample created. Comparing the B / D ratios for galaxies with and without B/PS bulges, we found that the B / D ratio for galaxies from our sample is statistically higher, with typical values in the range ≈0.2–0.5 depending on the decomposition procedure. We studied how the opening angles φ of the X-structure and the length of its rays are distributed in the formed sample and found them to be consistent with previous measurements and predictions from N -body models, e.g. |$\varphi \gtrsim 25{^\circ }$|⁠ , but measured here for a much larger number of galaxies. We found a sharp increase in the B/PS bulge fraction for stellar masses log  M ⋆ ≳ 10.4, but for edge-on galaxies, which complements the results of previous works. The sample can be used in future work to test various bar models and their relationship with B/PS bulges, as well as to study their stability and evolution. [ABSTRACT FROM AUTHOR]

Oxindole-based natural indoles analogues retain the rigidity and size of the original indole ring system whilst introducing more 3-dimensionality and potential increased water solubility. We report the first preparation of a diverse series of new melatonin analogues 4, 6, 11, 12 based on 3-hydroxy-2-oxindoles (11) and hydroxy-free 2-oxindoles (4, 6, 12) and evaluated their ability to reduce intraocular pressure as well as their neuroprotective and antioxidant properties. Reductive amination was used to obtain new 5-(benzylamino)-substituted (indolin-3-yl)acetonitriles 11 and (indolin-3-yl)acetic acids 12 with high yields. Compounds 4 a, c, 6 a and 11 a, d, h, j-l demonstrated IOP reduction effect in range 15-27 % similar to the effect of reference compounds melatonin and timolol (12 % and 18 % reduction, respectively). 5-(Benzylamino)-substituted 3-hydroxy-2-oxindoles 11, unlike compounds 4, 6, inhibited lipid peroxidation in range 2.075-13.012 μM. Inhibition of NQO2 associated with antioxidant properties of melatonin was also evaluated for synthesized compounds and it was found that compound 11 h showed the best NQO2 inhibitory activity with an IC 50 =39 μM (vs. melatonin IC 50 =64 μM). All synthesized compounds 4, 6, 11, 12 at a concentration of 30 μM do not possess the mitochondrial toxicity. Moreover, no disruption of tubulin polymerization was observed even in the presence of 100 μM of the compounds. Thus, 3-hydroxy-2-oxindole derivatives 11 can be used for drug design of first-in-class antiglaucoma drugs with antioxidant and neuroprotective properties., (© 2025 Wiley-VCH GmbH.)