Statistical Analysis of the Model Parameters of the Epidemic Situation

A calculation method and a variation method of parameters of the epidemic situation model taking into account external risks is proposed. The detailed step-by-step algorithm available in the application Exel for the calculation and analysis of the model parameters based on the results of observations is given. The prognosis of the epidemic situation with the estimation of the disease outbreak duration and the total number of population members involved in the outbreak is constructed. We investigated the epidemic situation by an example of reports of a diseases group acute viral respiratory infections-flu in one of the districts of the Moscow region

Structure evolution, bandgap, and dielectric function in La-doped hafnium oxide thin layer subjected to swift Xe ion irradiation

High-resolution transmission electron microscopy, electron diffraction, and electron energy-loss spectroscopy provide information on the structural evolution, dielectric function, and bandgap values of nanocrystalline 10nm thick lanthanum doped hafnia (La:HfO2) layers in TiN/La:HfO2/TiN/SiO2/Si irradiated with 24, 46, 72, and 160MeV (0.2-1.2MeV/u) Xe ions. Swift heavy Xe ions were expected to create significant atomic rearrangements when passed through a solid losing energy mainly through electronic excitation and ionization of the target atoms. Local heating and subsequent rapid cooling in the region around the ion track can lead to re-solidification with the formation of a new stable crystalline phase, and direct crystal-to-crystal transformations are possible. The structure evolution of hafnia nanocrystals from the orthorhombic Pbcm in the pristine layer to the tetragonal P4(2)/nmc phase in the 160MeV Xe ion irradiated layer was observed. The mixture of tetragonal and orthorhombic phases was found in samples irradiated with ions of intermediate energies. Textured hafnia layers were formed as a result of ion irradiation. The changes in plasmon line shape and the blueshift of the plasmon energy-loss peak from 14.9eV in the pristine layer to 15.4eV in 46MeV and 15.9eV in 160MeV Xe ion irradiated hafnia reflect structural transformations, the increase in the Hf coordination number, and crystal orientations. Valence-electron energy-loss spectroscopy measurements showed a slight increase in the bandgap value from 6.1eV in the pristine sample to 6.2eV and 6.3eV in irradiated samples with 46 and 160MeV Xe ions, respectively, and dielectric functions changed insignificantly in irradiated hafnia layers

Evaluation of the Efficiency of Photoelectrochemical Activity Enhancement for the Nanostructured LaFeO3 Photocathode by Surface Passivation and Co-Catalyst Deposition

Perovskite-type lanthanum iron oxide, LaFeO3, is a promising photocathode material that can achieve water splitting under visible light. However, the performance of this photoelectrode material is limited by significant electron-hole recombination. In this work, we explore different strategies to optimize the activity of a nanostructured porous LaFeO3 film, which demonstrates enhanced photoelectrocatalytic activity due to the reduced diffusion length of the charge carriers. We found that surface passivation is not an efficient approach for enhancing the photoelectrochemical performance of LaFeO3, as it is sufficiently stable under photoelectrocatalytic conditions. Instead, the deposition of a Pt co-catalyst was shown to be essential for maximizing the photoelectrochemical activity both in hydrogen evolution and oxygen reduction reactions. Illumination-induced band edge unpinning was found to be a major challenge for the further development of LaFeO3 photocathodes for water-splitting applications

Roughness Factors of Electrodeposited Nanostructured Copper Foams

Copper-based electrocatalytic materials play a critical role in various electrocatalytic processes, including the electroreduction of carbon dioxide and nitrate. Three-dimensional nanostructured electrodes are particularly advantageous for electrocatalytic applications due to their large surface area, which facilitates charge transfer and mass transport. However, the real surface area (RSA) of electrocatalysts is a crucial parameter that is often overlooked in experimental studies of high-surface-area copper electrodes. In this study, we investigate the roughness factors of electrodeposited copper foams with varying thicknesses and morphologies, obtained using the hydrogen bubble dynamic template technique. Underpotential deposition (UPD) of metal adatoms is one of the most reliable methods for estimating the RSA of highly dispersed catalysts. We aim to illustrate the applicability of UPD of lead for the determination of the RSA of copper deposits with hierarchical porosity. To find the appropriate experimental conditions that allow for efficient minimization of the limitations related to the slow diffusion of lead ions in the pores of the material and background currents of the reduction of traces of oxygen, we explore the effect of lead ion concentration, stirring rate, scan rate, monolayer deposition time and solution pH on the accuracy of RSA estimates. Under the optimized measurement conditions, Pb UPD allowed to estimate roughness factors as high as 400 for 100 µm thick foams, which translates into a specific surface area of ~6 m2·g−1. The proposed measurement protocol may be further applied to estimate the RSA of copper deposits with similar or higher roughness

Growth Peculiarities and Properties of KR3F10 (R = Y, Tb) Single Crystals

Cubic KR3F10 (R = Y, Tb) single crystals have been successfully grown using the Bridgman technique. Growth of crystals of this type is complicated due to the hygroscopicity of potassium fluoride and melt overheating. The solution to the problem of oxygen-incorporated impurities has been demonstrated through the utilization of potassium hydrofluoride as a precursor. In this study, the crystal quality, structure features, and optical, thermal and electrophysical properties of KR3F10 were examined. Data on the temperature dependences of conductivity properties of KTb3F10 crystals were obtained for the first time. These crystals indicated thermal conductivity equal to 1.54 ± 0.05 Wm−1K−1 at room temperature caused by strong phonon scattering in the Tb-based crystal lattice. Ionic conductivities of KY3F10 and KTb3F10 single crystals were 4.9 × 10−8 and 1.2 × 10−10 S/cm at 500 K, respectively, and the observed difference was determined by the activation enthalpy of F− ion migration. Comparison of the physical properties of the grown KR3F10 crystals with the closest crystalline analog from the family of Na0.5−xR0.5+xF2+2x (R = Tb, Y) cubic solid solutions is reported

Paramagnetic Relaxation Enhancement in Hydrophilic Colloids Based on Gd(III) Complexes with Tetrathia-and Calix[4]arenes

Copyright © 2020 American Chemical Society. Hydrophilic colloids (PSS-[Ln2(TCAi)2] and PSS-[LnCAi], where i = 1, 2, or 3 and Ln = Gd or Tb) were prepared by precipitation of Gd(III) or Tb(III) complexes with tetrathiacalix[4]arenes (TCAi) and calix[4]arenes bearing two 1,3-diketone groups (CAi) from dimethylformamide to an aqueous solution of poly(sodium 4-styrenesulfonate) (PSS). Dynamic light scattering and transmission electron microscopy demonstrated the formation of nanoparticles coated by the polymer. Luminescence decay measurements on Tb(III)-based colloids allowed hydration numbers of 2 and 4 per metal ion to be determined for PSS-[Ln2(TCAi)2] and PSS-[LnCAi] samples, respectively. Longitudinal and transverse water proton relaxivity values measured at 20.8 MHz were remarkably high for the PSS-[GdCAi] colloids but unexpectedly low for the PSS-[Gd2(TCAi)2] ones. 1H fast field cycling nuclear magnetic resonance relaxometry was applied to shed light on the origin of the different relaxation enhancement in the investigated systems. Extremely slow exchange with the bulk of water molecules coordinated to Gd(III) and the scarce accessibility of Gd(III) sites to water were highlighted as the main causes of limited relaxivity

Riboflavin Crystals with Extremely High Water Solubility

New insights into the unique biochemical properties of riboflavin (Rf), also known as vitamin B2, are leading to the development of its use not only as a vitamin supplement but also as a potential anti-inflammatory, immunomodulatory, antioxidant, anticancer, and antiviral agent, where it may play a role as an inhibitor of viral proteinases. At the same time, the comparison of the pharmacoactivity of Rf with its known metabolites, namely, flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), is very complicated due to its poor water solubility: 0.1–0.3 g/L versus 67 g/L for FMN and 50 g/L for FAD, which is the limiting factor for its administration in clinical practice. In this study, we report the recrystallization procedure of the type A Rf crystals into the slightly hydrophobic type B/C and a new hydrophilic crystal form that has been termed the P type. Our method of Rf crystal modification based on recrystallization from dilute alkaline solution provides an unprecedented extremely high water solubility of Rf, reaching 23.5 g/L. A comprehensive study of the physicochemical properties of type P riboflavin showed increased photodynamic therapeutic activity compared to the known types A and B/C against clinical isolates of Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Salmonella typhimurium. Importantly, our work not only demonstrates a simple and inexpensive method for the synthesis of riboflavin with high solubility, which should lead to increased bioactivity, but also opens up opportunities for improving both known and new therapeutic applications of vitamin B2