Characterizations of modalities and lex modalities

A reflective subuniverse in homotopy type theory is an internal version of the notion of a localization in topology or in the theory of ∞-categories. Working in homotopy type theory, we give new characterizations of the following conditions on a reflective subuniverse L: (1) the associated subuniverse $L^{\prime }$ of L-separated types is a modality; (2) L is a modality; (3) L is a lex modality; and (4) L is a cotopological modality. In each case, we give several necessary and sufficient conditions. Our characterizations involve various families of maps associated to L, such as the L-étale maps, the L-equivalences, the L-local maps, the L-connected maps, the unit maps ${\eta }_X$, and their left and/or right orthogonal complements. More generally, our main theorem gives an overview of how all of these classes related to each other. We also give examples that show that all of the inclusions we describe between these classes of maps can be strict.     

Oxidation of methane to methanol with hydrogen peroxide in situ in the presence of glutathione-stabilized gold nanoclusters under mild conditions

Russian Chemical Bulletin - Oxidation of methane with a hydrogen-air mixture at 70 °C and a partial pressure of methane of 30 atm was studied. Water-soluble glutathione-stabilized nanoclusters...     

Microextraction of 17-β-Estradiol from Medicinal Preparations for the Subsequent Determination by HPLC-UV

Journal of Analytical Chemistry - A method is proposed for the chromatographic determination of 17-β-estradiol in medicinal preparations with the microextraction of the analyte from a sample...     

Dendritic polyurethane-based prodrug as unimolecular micelles for precise ultrasound-activated localized drug delivery

Ultrasound has been recognized as an exciting tool to enhance the therapeutic efficacy in tumor chemotherapy owing to the triggered drug release, facilitated intracellular drug delivery, and improved spatial precision. Aiming for a precise localized drug delivery, novel dendritic polyurethane-based prodrug (DOX-DPU-PEG) was fabricated with a drug content of 18.9% here by conjugating DOX onto the end groups of the functionalized dendritic polyurethane via acid-labile imine bonds. It could easily form unimolecular micelles around 38 nm. Compared with the non-covalently drug-loaded unimolecular micelles (DOX@Ph-DPU-PEG), they showed excellent pH/ultrasound dual-triggered drug release performance, with drug leakage of only 4% at pH 7.4, but cumulative release of 14% and 88% at pH 5.0 without and with ultrasound, respectively. The ultrasound responsiveness was attributed to the unique strawberry-shaped topological structure of the DOX-DPU-PEG, in which DOX was embedded in the skin layer of the hydrophobic DPU cores. With ultrasound, the DOX-DPU-PEG unimolecular micelles possessed enhanced tumor growth inhibition than free DOX but showed no obvious cytotoxicity on the tumor cells without ultrasound. Such feature makes them promising potential for precise localized drug delivery.     

Application of advanced nuclear analytical techniques for the electrocatalyst's characterization: Paving the path for mechanistic investigations

As the application of electrocatalyst continues to expand, envisaging the hidden mechanisms occurring at various length scale affecting the catalytic efficiency became important. To enhance the stability of electrocatalyst and reduce the cost, it is of paramount importance to reveal the active site's dynamics (using in situ techniques for getting the real-time information) which directly affect the reactions such as oxygen evolution reaction, hydrogen evolution reaction, and so on. Since such reactions are crucial for many engineering and scientific applications, in situ characterization techniques are required, which could capture such reactions happening at a different length and time scale. This article analyzes the recent progress made in the field of electrocatalyst's characterization using in situ neutron techniques. The article also paves the future path and has delineated the future challenges involved in multiscale correlative techniques (e.g., neutron techniques in the combination of synchrotron or microscopic techniques) used for getting the multiscale (atomic to micrometer range) mechanistic information about the electrocatalyst's working and degradation.     

Low-Temperature Physical Mechanism of Inelastic Strain of Metallic Glass

Russian Physics Journal - The paper deals with the low-temperature physical mechanism of inelastic strain of metallic glass, which is the quantum atomic tunneling in a double well potential or...     

Coherent States of a Free Particle with Varying Mass in the Probability Representation of Quantum Mechanics

Journal of Russian Laser Research - We construct Gaussian coherent states of a free particle with time-dependent mass, using symplectic tomographic probability distribution and integrals of motion...     

Regularities of Structure Formation in AA2024 Alloy During High-Intensity Plastic Deformation Under Conditions of Adhesion-Diffusion Friction Interaction

Russian Physics Journal - The results of model experimental studies of structural-phase changes in an AA2024 aluminum alloy after friction with a counter-body of a complex configuration are...     

WEAR OF DRY FRICTION PAIRS CONSISTING OF HIGH-CARBON CHROME-VANADIUM STEELS AND HARD ALLOYS

Journal of Applied Mechanics and Technical Physics - The wear resistance of DI37-VI and EK80-VI steel is studied using a friction testing device. A sample made of high-carbon chromium-vanadium...