Since 1986, a collaboration between the Boreskov Institute of Catalysis (BIC) and the Budker Institute of Nuclear Physics (BINP) has been producing silica aerogel blocks for Cherenkov detectors. Novosibirsk-manufactured aerogel has been employed in several experiments, including KEDR and SND (BINP, Russia), DIRAC and LHCb (CERN, Switzerland), AMS-02 (ISS), and CLAS12 (Jefferson Lab, USA). This work describes key advances in the production technology of large-scale aerogel radiators used in Ring-Imaging CHerenkov (RICH) detectors. Annealing is one of the key stages in the production of highly transparent aerogel in Novosibirsk. This process was studied in detail and optimized to improve the yield of aerogel tiles suitable for RICH detectors. The optical and mechanical properties of the largest silica aerogel samples produced in Novosibirsk using the new annealing procedure are presented.
This study aimed to conduct phytochemical screening and multi-analytical characterization of C. sativa leaves cultivated in the Mount Kenya region (Lower Imenti, Kenya) to establish a chemical baseline for regional hemp-type C. sativa. Different leaf extracts (hexane, dichloromethane, ethanol, and aqueous) were prepared via standard solvent extraction and subjected to qualitative phytochemical screening, total phenolic-content assays, and multi-analytical techniques including HPLC, GC–MS, LC–MS, FT-IR, UV–VIS, and AAS. Phytochemical screening revealed that phenols, alkaloids, and reducing sugars were abundant across extracts, while steroids, triterpenoids, and fixed oils were more prevalent in non-polar solvents. Total phenolic-content was highest in the ethanolic extract (150.05 mg GAE/g), followed by aqueous, dichloromethane, and hexane extracts. HPLC and GC–MS identified catechin hydrate, naringin, rutin, hesperidin-type flavonoids, and major phenolic acids such as linoleic and linolenic acids, while LC–MS confirmed a CBD-dominant cannabinoid profile with cannabigerol, cannabidiol, Δ⁹-THC, and flavonoids. FT-IR and UV–VIS spectra corroborated phenolic-rich, proteinaceous, and lipophilic constituents. AAS revealed elevated levels of both essential micronutrients and toxic heavy metals Pb, As, and Cd exceeding WHO permissible limits for medicinal plants (Pb ≤ 0.3 ppm, As ≤ 0.2 ppm, Cd ≤ 0.2 ppm), indicating soil contamination and potential health risks. The findings demonstrate that C. sativa from Mount Kenya is phytochemically rich but heavily contaminated by Pb, As, and Cd; soil remediation, regular heavy-metal monitoring, and strict regulatory control are therefore recommended before any medicinal or commercial application.
Capillary zone electrophoresis (CZE) was employed to quantify major cations (K+, Na+, Ca2+, Mg2+) and anions (Cl−, SO_4^2 - , PO_4^3 - , lactate, citrate) in blood serum samples obtained from 40 healthy donors aged from 20 to 85 years. Ammonium concentration (µmol/L) was additionally measured in capillary blood, as this cation was not reliably detectable in deproteinized serum using CZE due to its methodological limitations. Statistical analysis revealed sex-based differences only for ammonium (p = 0.001), with higher levels observed in men compared to women (median 97.5 µmol/L vs. 89 µmol/L, respectively). Statistically significant age-related differences were observed for phosphate (p = 0.04), ionized calcium (p = 0.008), as well as Na/K (p = 0.01) and Mg/Ca (p = 0.003) ratios. Ionized calcium levels in older donors (65–85 years) were lower than in younger groups and fell below reference ranges. Lactate concentrations in young and middle-aged donors slightly exceeded literature reference values. This study established reference intervals in blood serum for all the analytes studied, including sulfate and citrate ions, for which there is almost no information in the literature about the normal concentrations of these ions. Correlation analysis revealed statistically significant positive correlations between chloride and lactate, potassium and sodium, chloride and sulfate, and magnesium and ionized calcium in serum (p < 0.05). These results support the applicability of CZE for ion determination in blood serum and provide valuable reference data for clinical practice.
Three new pyridazine derivatives are synthesized and characterized: 3-chloro-6-(3,5-di-tert-butyl-1H-pyrazol-1-yl)pyridazine (L2), 3-(3,5-di-tert-butyl-1H-pyrazol-1-yl)-6-hydrazinopyridazine (L3), and 2-((2-(6-(3,5-di-tert-butyl-1H-pyrazol-1-yl)pyridazin-3-yl)hydrazineylidene)methyl)phenol (H2L4). Compounds L2 and L3 can act as chelate N-donor ligands, H2L4 can act as a polydentate N- and O-donor ligand. All compounds are described by the elemental analysis, powder X-ray diffraction (XRD), IR, electronic, and NMR NMR (1H, 13C) spectroscopic techniques, and their melting points are determined. The crystal structures of L2 and H2L4 compounds are determined by the single crystal XRD analysis. The powder XRD analysis reveals that the L2, L3, and H2L4 compounds are pure phases. The L2 and H2L4 compounds have the molecular structure. The structure of the latter consists of two crystallographically independent molecules forming dimers via pair intermolecular N–H⋯N hydrogen bonds (dN⋯N distances of 3.06 Å and 3.00 Å). A short intramolecular hydrogen bond is observed in the H2L4 molecule, which is confirmed by dO⋯N and dH⋯N distances of 2.66 Å and 1.9 Å at the sum of nitrogen and hydrogen atomic Bondi radii of 2.65 Å (RH + RN). In the L2 and H2L4 molecules, the N1 (pyrazole ring) and N3 (pyridazine ring) atoms are in the trans-position. From the electronic and 1H NMR spectroscopic data it follows that it is possible to completely deprotonate the H2L4 molecule with trimethylamine in acetonitrile and chloroform.
Photons carrying orbital angular momentum, also known as twisted photons, hold the potential to reveal new insights in atomic and molecular spectroscopy measurements. In this work, we explored magnetic dipole (M1) transitions induced by twisted photons for their application in electron paramagnetic resonance spectroscopy. We calculated the corresponding transition matrix elements and compared them with those of conventional plane wave photons. Our study showed that the matrix elements of twisted photons qualitatively differ from those of plane wave photons and linked this difference to the fact that twisted photon states are a superposition of states with photon spin projections onto the direction of propagation of -1, 0, and 1. According to our study, M1 excitations induced by twisted photons exhibit a spatial dependence on the perpendicular momentum, the radial position of the sample, and the total angular momentum projection of the photon. In addition, we illustrated the characteristic features of M1 transitions induced by twisted photons using model systems with total spin S = 1/2 and S = 3/2, which are the representative of typical organic radicals and high-spin transition metal complexes, respectively. In particular, the S = 3/2 system with zero-field splitting, where the energy levels increase or decrease depending on the spin projection (from -3/2 to +3/2), clearly highlights the qualitative distinctions in excitation behavior introduced by twisted light. Finally, numerical simulations performed for point-like and pellet-like samples under experimentally relevant THz beam conditions corroborate the theoretical predictions and provide a practical framework for future experimental validation.
