Publications by authors named "Antonov a"

Zr-monosubstituted polyoxometalates (Zr-POMs) of the Keggin (BuN)[{PWOZr(μ-OH)}] (Zr-K), Lindqvist (BuN)[{WOZr(μ-OH)}] (Zr-L), and Wells-Dawson (BuN)H[{PWOZr(μ-OH)}] (Zr-WD) structures are capable of heterolytic activation of the environmentally benign oxidant tert-butyl hydroperoxide (TBHP) and catalyze epoxidation of alkenes and oxidation of alcohols to carbonyl compounds. Catalytic activity of corresponding Ti-POMs is much lower. Among Zr-POMs, Zr-K revealed higher epoxide yields.

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Friction is central to the motion of active (self-propelled) objects such as bacteria, animals, and robots. While in a viscous fluid friction is described by Stokes's law, objects in contact with other solid bodies are often governed by more complex empirical friction laws. Here, we study active particles subject to Coulomb friction using a combination of active granular experiments and simulations, supported by theoretical predictions.

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Purpose: This study assesses the impact of preoperative administration of Oku-Oku eye drops on the severity of conjunctival hyperemia and the risk of hemorrhagic complications in the early postoperative period following glaucoma surgery.

Material And Methods: The study included a group of 30 patients (30 eyes) with uncontrolled primary open-angle glaucoma who underwent non-penetrating deep sclerectomy. The main group included 15 eyes, in which Oku-Oku drops were administered twice - on the day before surgery (upon hospital admission) and immediately before the operation.

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Non-covalent interactions, including the coordination of an organolithium reagent by a directing group and the steric hindrance from substituents, play a crucial role in determining the selectivity of metalation reactions. Here, we demonstrate the effective utilization of steric interactions for flipping the lithiation of 4-dimethylaminopyridine (DMAP). Introduction of a MeSi substituent to the position 1 of DMAP or simple complexation with t-BuLi allows selective C3-lithiation, due to the steric hindrance of a C2-H bond by the bulky moiety at the pyridine nitrogen.

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Understanding and predicting viewers' emotional responses to videos has emerged as a pivotal challenge due to its multifaceted applications in video indexing, summarization, personalized content recommendation, and effective advertisement design. A major roadblock in this domain has been the lack of expansive datasets with videos paired with viewer-reported emotional annotations. We address this challenge by employing a deep learning methodology trained on a dataset derived from the application of System1's proprietary methodologies on over 30,000 real video advertisements, each annotated by an average of 75 viewers.

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We present the first results from a proof-of-concept search for dark sectors via invisible decays of pseudoscalar η and η^{'} mesons in the NA64h experiment at the CERN SPS. Our novel technique uses the charge-exchange reaction of 50 GeV π^{-} on nuclei of an active target as the source of neutral mesons. The η,η^{'}→invisible events would exhibit themselves via a striking signature-the complete disappearance of the incoming beam energy in the detector.

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Zr-monosubstituted polyoxometalates (Zr-POMs) of the Lindqvist (BuN)[{WOZr(μ-OH)}] (), Keggin (BuN)[{PWOZr(μ-OH)}] (), and Wells-Dawson (BuN)KH[{PWOZr}(μ-OH)] () structures catalyze oxidation of alcohols using aqueous hydrogen peroxide as an oxidant. With 1 equiv of HO and 1 mol % of Zr-POM, selectivity toward aldehydes and ketones varied from good to excellent, depending on the alcohol nature. Catalytic activity and attainable substrate conversions strongly depended on the Zr-POM structure and most often decreased in the order > ≫ .

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Nuclear magnetic resonance (NMR) spectroscopy is a powerful tool for studying the structure and dynamics of various non-covalent interactions. However, often spectral parameters that are applicable for estimation of parameters of one type of non-covalent interaction will be inapplicable for another. Therefore, researchers are compelled to use spectral parameters that are specifically tailored to the type of non-covalent interaction being studied.

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Achieving precise spectral and temporal light manipulation at the nanoscale remains a critical challenge in nanophotonics. While photonic bound states in the continuum (BICs) have emerged as a powerful means of controlling light, their reliance on geometrical symmetry breaking for obtaining tailored resonances makes them highly susceptible to fabrication imperfections, and their generally fixed asymmetry factor fundamentally limits applications in reconfigurable metasurfaces. Here, we introduce the concept of environmental symmetry breaking by embedding identical resonators into a surrounding medium with carefully placed regions of contrasting refractive indexes, activating permittivity-driven quasi-BIC resonances (ε-qBICs) without altering the underlying resonator geometry and unlocking an additional degree of freedom for light manipulation through active tuning of the surrounding dielectric environment.

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Ten new decalin polyketides, zosteropenilline M (), 11--8-hydroxyzosteropenilline M (), zosteropenilline N (), 8-hydroxyzosteropenilline G (), zosteropenilline O (), zosteropenilline P (), zosteropenilline Q (), 13-dehydroxypallidopenilline A (), zosteropenilline R () and zosteropenilline S (), together with known zosteropenillines G () and J (), pallidopenilline A () and 1-acetylpallidopenilline A (), were isolated from the ethyl acetate extract of the fungus KMM 4679 associated with the seagrass . The structures of isolated compounds were established based on spectroscopic methods. The absolute configurations of zosteropenilline Q () and zosteropenilline S () were determined using a combination of the modified Mosher's method and ROESY data.

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Britholites are the lanthanide-silica-rich end-members of the apatite group, commonly studied for their optical properties. Here, we show ∼50-100 μm single crystals synthesized hydrothermally at 650-500 °C and 500-300 MPa composed of a solid solution between CaPr(SiO)F-fluorbritholite and CaPr(SiO)O-oxybritholite, with a significant carbonate component substitution, via C replacing Si. Single-crystal X-ray diffraction and density functional theory computations show that a planar carbonate group occupies the face of a now-vacant silica tetrahedron.

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Article Synopsis
  • - Since its discovery in Africa, the West Nile virus has spread globally, becoming common in many countries, including Russia, with significant expansion occurring there in 1999.
  • - Research on the virus in Russia has gained importance, leading to a large dataset collected since 2007 to understand its genetic diversity and spread.
  • - A study analyzing 55 complete genome sequences found that the West Nile virus in Russia is genetically diverse, classified into four main groups, with one group spreading rapidly to new areas.
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Body composition assessment is often used in clinical practice to assess and monitor nutritional status. For example, body fat mass is a predictor of metabolic diseases, and for an athlete it is a criterion of performance. "Gold standard" - the method of dual-energy X-ray absorptiometry - in contrast to bioelectrical impedance analysis, is difficult to apply in everyday clinical practice.

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The activation of poorly reactive substrates via strong chiral acids is a central topic in asymmetric ion pair catalysis these days. Despite highly successful scaffolds such as N-triflylphosphoramides, these catalysts either lack C2-symmetry or provide multiple H-bond acceptor sites, leading to lower ee values for certain reactions. We present BINOL-based diselenophosphoric acids (DSA) as an extremely promising alternative.

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Purpose: This study assesses the light sensitivity and its variability in each point of the visual field in patients without glaucoma and with different stages of glaucoma.

Material And Methods: The data of a prospective analytical case-control study involving 500 patients were analyzed. The initial examination of all patients was performed using basic ophthalmological methods, including static perimetry.

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Article Synopsis
  • The study looked at how changes in eye curvature (keratometry) after refractive surgery affect the accuracy of a specific eye pressure measurement (Maklakov tonometry).
  • A total of 61 participants were involved, divided into groups based on their type of eye surgery, including LASIK, FS-LASIK, and PRK, and compared with a control group that hadn't undergone surgery.
  • The results indicated that the 10 g weight provided the most reliable tonometry readings influenced by eye curvature across various groups, while the 5 g weight readings showed the least correlation, especially in those who had LASIK surgery.
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Purpose: This study investigates the influence of peripheral corneal thickness (PCT) and its curvature on tonometry readings.

Material And Methods: The study included 49 patients (49 eyes) who were indicated for glaucoma surgery. Using bidirectional applanation tonometry, the following parameters were obtained: IOPcc, IOPg - intraocular pressure (IOP) corrected for corneal compensation, taken as the most reliable indicator; IOP converted to Goldmann measurement, taken as the result of applanation tonometry, ΔIOP (IOPcc-IOPg), CH and CRF (corneal hysteresis and corneal resistance factor).

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Purpose: This study analyzes changes in light sensitivity in each test point of the visual field in patients with different stages of glaucoma.

Material And Methods: The data of a prospective analytical case-control study were analyzed. All patients underwent assessment of retinal light sensitivity and its variability in 54 points corresponding to the 24-2 program.

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Solvothermal reaction of magnesium nitrate and boron oxide in ,-dimethylformamide produced a number of particularly complex supramolecular magnesium borates. Five topologically different types of negatively charged {Mg@[Bφ]}-clusters, φ = O, OH, were observed with the magnesium cation as a core and octadecaborate anions as shells. The clusters assemble common borate polyhedra forming 1D chains, a 2D mesoporous layer, and 3D mesoporous frameworks with an effective channel width of up to 16 Å.

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Unlabelled: Cataract phacoemulsification with intraocular lens implantation significantly affects the morphology of the anterior chamber angle (ACA) and contributes to a reduction of intraocular pressure (IOP).

Purpose: This study investigates the changes in anterior chamber angle configuration and IOP level before and after cataract surgery in primary open-angle glaucoma (POAG) eyes, and assesses its possible relationship with the axial length of the eye.

Material And Methods: The study included 38 patients with immature senile cataract and compensated unoperated stage I-II POAG.

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A simple and effective organolithium approach to the synthesis of 2-substituted benzo[cd]indoles from peri-dihalonaphthalenes and nitriles has been developed. The reaction proceeds via a surprisingly easy intramolecular aromatic nucleophilic substitution facilitated by the "clothespin effect". The discovered transformation provides good isolated yields, allows usage of an extensive range of nitriles, and demonstrates a good substituents tolerance.

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For the first time through quantum chemistry methods, the effective use of spin-spin coupling constants as descriptors for assessing the formation of strained metallacycles is demonstrated. Both acyclic organolithiums and 3- to 7-membered metallacycles are examined. 80 organolithium compounds, including both monomeric and dimeric species, with ligands containing fluorine, nitrogen, oxygen, and carbon (in the form of carbanions), are tested.

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Non-covalent interactions such as coordination of an organolithium reagent by a directing group and steric repulsion of substituents strongly affect the halogen-lithium exchange process. Here we present the manifestation of the "buttressing effect" - an indirect interaction between two substituents issued by the presence of a third group - and its influence on the ease and selectivity of the bromine-lithium exchange and the reactivity of formed aryllithiums. The increase of the size of the "buttressing" substituent strongly affects the conformation of a NMe group, forcing it to hinder ortho-bromine and thus slowing down the exchange.

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Moyamoya disease (MMD) is a rare cerebrovascular disorder characterized by the progressive narrowing and occlusion of the intracranial internal carotid arteries, leading to the formation of abnormal collateral vessels. MMD primarily affects the cerebrovascular system, and evidence suggests it is associated with various neuropsychiatric outcomes. This manuscript aims to provide an overview of the current understanding of MMD, including its epidemiology, pathophysiology, clinical manifestations, and diagnosis.

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