Protective Effect of Meso-Tetrakis-(3,5-di-tert-butyl-4-hydroxyphenyl)porphyrin on the In Vivo Impact of Trimethyltin Chloride on the Antioxidative Defense System

The in vivo effect of trimethyltin chloride (Me(3)SnCl), free base meso-tetrakis(3,5-di-tert-butyl-4-hydroxyphenyl)porphyrin (R′(4)PH(2)) and their equimolar mixture, on the enzymatic activity of catalase (CAT), superoxide dismutase (SOD), and on the total content of free sulfhydryl groups has been studied in rat liver and kidney. It was demonstrated that the simultaneous treatment of tested animals with the combination of Me(3)SnCl and R′(4)PH(2) reduced the toxic impact of Me(3)SnCl

Minimal information for studies of extracellular vesicles (MISEV2023): From basic to advanced approaches

Extracellular vesicles (EVs), through their complex cargo, can reflect the state of their cell of origin and change the functions and phenotypes of other cells. These features indicate strong biomarker and therapeutic potential and have generated broad interest, as evidenced by the steady year-on-year increase in the numbers of scientific publications about EVs. Important advances have been made in EV metrology and in understanding and applying EV biology. However, hurdles remain to realising the potential of EVs in domains ranging from basic biology to clinical applications due to challenges in EV nomenclature, separation from non-vesicular extracellular particles, characterisation and functional studies. To address the challenges and opportunities in this rapidly evolving field, the International Society for Extracellular Vesicles (ISEV) updates its 'Minimal Information for Studies of Extracellular Vesicles', which was first published in 2014 and then in 2018 as MISEV2014 and MISEV2018, respectively. The goal of the current document, MISEV2023, is to provide researchers with an updated snapshot of available approaches and their advantages and limitations for production, separation and characterisation of EVs from multiple sources, including cell culture, body fluids and solid tissues. In addition to presenting the latest state of the art in basic principles of EV research, this document also covers advanced techniques and approaches that are currently expanding the boundaries of the field. MISEV2023 also includes new sections on EV release and uptake and a brief discussion of in vivo approaches to study EVs. Compiling feedback from ISEV expert task forces and more than 1000 researchers, this document conveys the current state of EV research to facilitate robust scientific discoveries and move the field forward even more rapidly

Фильтрационная модель скального основания напорного гидроузла

Введение. Предложено создание фильтрационной модели основания гидроузла, по которой могут быть выполнены сложные проектные фильтрационные расчеты. Модель природной среды отличается от реальной природной среды тем, что характеризует только одну сторону природного объекта, в данном случае - фильтрационную способность. В предложенной фильтрационной модели скальное основание разделено на несколько инженерно-геологических расчетных элементов с разной водопроницаемостью. Это расчленение - сложная задача, поскольку значения коэффициента фильтрации для скального основания в целом имеют большой разброс, причем, зачастую, тесно соседствуют существенно разные значения. Предложено решение путем математико-статистического обобщения результатов массового фильтрационного опробования скального массива. Материалы и методы. Наиболее распространенным подходом построения модели является определение в точках массива гидравлическим способом откачек и нагнетаний воды в скважины, а также расчетный путь, когда коэффициент фильтрации массива рассчитывается по параметрам трещин. Материалом для построения инженерно-геологической фильтрационной модели служат данные стандартных массовых определений коэффициента фильтрации и удельного водопоглощения, полученные при изысканиях. Результаты. Одним из преимуществ предложенной фильтрационной модели скального основания гидроузла является форма и методика построения путем математико-статистического обобщения результатов массового фильтрационного опробования скального массива. По форме модель представляет собой принятые в проектно-изыскательском деле геологические разрезы основания плотины вдоль оси и по поперечникам. В дальнейшем развитие методики планируется с учетом современных средств программирования и представления модели в 3D форме. Содержание модели выражает геолого-генетическую оценку фильтрационной неоднородности, сформированной в ходе геологических процессов, протекавших в массиве основания. Выводы. Предложенная модель основания гидроузла может быть построена по результатам позонного фильтрационного опробования буровых скважин в отдельных точках массива горных пород. Сложная задача разделения массива основания на зоны с различной водопроницаемостью решается на основе геолого-генетического подхода в сочетании с математико-статистическим анализом. Практическая значимость данной фильтрационной модели в том, что с ее помощью могут быть запроектированы надежные гидротехнические сооружения с обеспечением устойчивости и минимизации фильтрационных потерь

Aeroacoustics of supersonic jet issued from corrugated nozzle: new approach and prospects

It is generally accepted that one of the main sources of acoustic radiation from a supersonic jet is due to spatial instability wave packets propagating downstream within the jet. This approach has enabled us to explain and predict the principal features of sound radiated by a supersonic jet witha circular nozzle. The aim of this present work is to generalize such an approach to jets with acircular nozzle deformed into a weakly corrugated (s-lobed) shape. This leads to the presence oftwo additional parameters, the lobe number (an integer) characterizing the corrugation wavelength and the corrugation amplitude. Their presence can be shown to lead to a resonant coupling between different instability waves which, in turn, can both intensify and suppress the aerodynamic noise.The assumption of a small corrugation amplitude allows us to consider the problem analytically using disturbance theory methods. The structure of the eigen-oscillations is determined at leading orders, where it is shown that differing azimuthal harmonics are coupled over a wide range of frequencies. The result of such couplings on the radiated sound is significant, even for a small corrugation amplitude. The above suggests that the effect of mode coupling, due to nozzle corrugation, could be used as a tool for noise control in supersonic jets

Diversity Oriented Synthesis of Polycyclic Heterocycles through the Condensation of 2‑Amino[1,2,4]triazolo[1,5‑<i>a</i>]pyrimidines with 1,3-Diketones

The acid-catalyzed condensation between 2-aminosubstituted [1,2,4]­triazolo­[1,5-<i>a</i>]­pyrimidines and their analogues with various saturation of the pyrimidine ring and 1,3-diketones or 1,1,3,3-tetramethoxypropane was evaluated as a new approach for the synthesis of diversely substituted polycyclic derivatives of triazolopyrimidine. The reaction of 4,5,6,7-tetrahydro- or aromatic aminotriazolopyrimidines results in selective formation of the corresponding [1,2,4]­triazolo­[1,5-<i>a</i>:4,3-<i>a</i>′]­dipyrimidin-5-ium salts, and the condensation of substrates containing the 4,7-dihydro-[1,2,4]­triazolo­[1,5-<i>a</i>]­pyrimidine fragment is accompanied by a cascade rearrangement with unusual recyclization of the dihydropyrimidine ring to yield partially hydrogenated [1,2,4]­triazolo­[1,5-<i>a</i>:4,3-<i>a</i>′]­dipyrimidin-5-ium or pyrimido­[1′,2′:1,5]­[1,2,4]­triazolo­[3,4-<i>b</i>]­quinazolin-5-ium salts. The proposed methodology exhibits a wide scope, providing rapid access to polycondensed derivatives of the [1,2,4]­triazolo­[1,5-<i>a</i>]­pyrimidine scaffold. DFT calculations of the Gibbs free energies of possible isomers were performed to rationalize the experimentally observed reactivity and selectivity

Ionic Pd/NHC Catalytic System Enables Recoverable Homogeneous Catalysis: Mechanistic Study and Application in the Mizoroki–Heck Reaction

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Facile Hydrolysis of Nickel(II) Complexes with N‑Heterocyclic Carbene Ligands

Metal complexes with N-heterocyclic carbene ligands (NHC) are ubiquitously used in catalysis, where the stability of the metal–ligand framework is a key issue. Our study shows that Ni-NHC complexes may undergo facile decomposition due to the presence of water in organic solvents (hydrolysis). The ability to hydrolyze Ni­(NHC)₂X₂ complexes decreases in the order of NHC = 1,2,4-triazolium > benzimidazolium ≈ imidazolium. Depending on the ligand and substituents, the half reaction time of the complex decomposition may change from several minutes to hours. The nature of the halogen is also an important factor, and the ability for decomposition of the studied complexes decreases in the order of Cl > Br > I. NMR and MS monitoring revealed that Ni-NHC complexes in the presence of water undergo hydrolysis with Ni–C_carbene bond cleavage, affording the corresponding <i>N</i>,<i>N</i>′-dialkylated azolium salts and nickel­(II) hydroxide. These findings are of great importance for designing efficient and recyclable catalytic systems, because trace water is a common contaminant in routine synthetic applications