Assessment of registered and hidden epidemic process of tick-borne encephalitis in the Republic of Karelia

Introduction. The incidence of tick-borne encephalitis in the Russia remains relevant. The assessment of the epidemic process in the Republic of Karelia is important not only in terms of understanding its general patterns, but in connection with the growth of tourist attendance in the region. Aims: To assess the current epidemic situation of tick-borne encephalitis in the Republic of Karelia, and to compare the characteristics of registered and hidden epidemic processes. Materials and methods. The risk of infection and incidence were estimated based on the analysis of the registered cases of seeking medical help in connection with tick bites, the results of a study of tick-borne encephalitis virus (TBEV) infection rate in ticks, and the epidemiological investigation of cases of tick-borne encephalitis in 1992–2022. Clinical, gender and age structure, territorial distribution of patients and victims of the tick bites were compared with the results of serological studies of 2379 blood samples of the adult population, conducted in 2011–2022. Results. Infection rates of ticks removed from humans ranged from 23.6–27.0% in 2002–2005 to 1.0% in 2022. In 2004, the TBEV antigen was detected in mosquitoes. The territory of risk is the southern part of Republic. However, the increase in number of cases of seeking medical help was observed in the northern part of Republic. The incidence rates exceeded the national average, especially in 2003–2004 (15.3–11.6 per 100 thousand). In 2021–2022, it decreased to 1.8–1.5 per 100,000. The dynamics of incidence had a high-degree correlation with the dynamics of seeking medical help and infection rates in ticks (R = 0.92 and 0.73). The reported incidence was lower than the estimated risk of infection. The meningeal forms of infection were most often diagnosed. The risk of the disease was higher in the elderly and in men, which was determined by the conditions of infection. Antibodies to TBEV were detected in 11.8 ± 0.7% of the examined persons. Conclusion. A steady decrease in rates of registered tick-borne encephalitis incidence has been revealed in the Republic of Karelia, mainly due to the action of biological and natural factors. The assessment of seroprevalence made it possible to reveal the hidden part of the epidemic process

A high-temperature furnace for in situ synchrotron X-ray spectroscopy under controlled atmospheric conditions.

A high-temperature furnace with an induction heater coil has been designed and constructed for in situ X-ray spectroscopic experiments under controlled atmospheric conditions and temperatures up to 3275 K. The multi-purpose chamber design allows working in backscattering and normal fluorescence mode for synchrotron X-ray absorption and emission spectroscopy. The use of the furnace is demonstrated in a study of the in situ formation of Cr oxide between 1823 K and 2023 K at logPO(2) values between -10.0 and -11.3 using X-ray absorption near-edge spectroscopy. The set-up is of particular interest for studying liquid metals, alloys and other electrically conductive materials under extreme conditions

Scientific Opportunities for Heterogeneous Catalysis Research at the SuperXAS and SNBL Beam Lines

In this short review, we describe the complementary experimental capabilities for catalysis research at two beam lines available to the Swiss community, SuperXAS at SLS (Swiss Light Source, Villigen) and SNBL (Swiss Norwegian Beam lines) at ESRF (European Synchrotron Radiation Facility, Grenoble). Over the years, these two facilities have been developed to provide powerful techniques for structural studies under in situ and operando conditions. These techniques, X-ray diffraction (XRD), X-ray absorption spectroscopy (XAS), and X-ray emission spectroscopy (XES) in combination with Raman or infrared spectroscopy provide new avenues for structure–performance studies of catalysts. Several exemplary studies are used to demonstrate the capability of these facilities

In Situ X-ray Absorption Spectroscopy of LaFeO₃ and LaFeO₃/LaNiO₃ Thin Films in the Electrocatalytic Oxygen Evolution Reaction

We study the electrocatalytic oxygen evolution reaction using in situ X-ray absorption spectroscopy (XAS) to track the dynamics of the valence state and the covalence of the metal ions of LaFeO3 and LaFeO3/LaNiO3 thin films. The active materials are 8 unit cells grown epitaxially on 100 nm conductive La0.67Sr0.33MnO3 layers using pulsed laser deposition (PLD). The perovskite layers are supported on monolayer Ca2Nb3O10 nanosheet-buffered 100 nm SiNx membranes. The in situ Fe and Ni K-edges XAS spectra were measured from the backside of the SiNx membrane using fluorescence yield detection under electrocatalytic reaction conditions. The XAS spectra show significant spectral changes, which indicate that (1) the metal (co)valencies increase, and (2) the number of 3d electrons remains constant with applied potential. We find that the whole 8 unit cells react to the potential changes, including the buried LaNiO3 film.</p

Surface Redox Dynamics in Gold-Zinc CO2 Hydrogenation Catalysts

Au-Zn catalysts have previously been shown topromote thehydrogenation of CO2 to methanol, but their active stateis poorly understood. Here, silica-supported bimetallic Au-Znalloys, prepared by surface organometallic chemistry (SOMC), are shownto be proficient catalysts for hydrogenation of CO2 tomethanol. In situ X-ray absorption spectroscopy (XAS),in conjunction with gas-switching experiments, is used to amplifysubtle changes occurring at the surface of this tailored catalystduring reaction. Consequently, an Au-Zn alloy is identifiedand is shown to undergo subsequent reversible redox changes underreaction conditions according to multivariate curve resolution alternatingleast-squares (MCR-ALS) analysis. These results highlight the roleof alloying and dealloying in Au-based CO2 hydrogenationcatalysts and illustrate the role of these reversible processes indriving reactivity.ISSN:0002-7863ISSN:1520-512

Infrared Studies on Bimetallic Copper/Nickel Catalysts Supported on Zirconia and Ceria/Zirconia

Infrared spectroscopy has been employed for a detailed characterization of ZrO2 and CeO2/ZrO2 supported nickel and copper/nickel catalysts to be utilized for methane decomposition. Adsorption of CO at 303 K was performed in order to determine the surface composition and accessible adsorption sites. Alloy formation occurred during reduction, as indicated by a red-shift of the vibrational band of CO on Ni: by 27 cm−1 on nickel-rich CuNi alloy, by 34 cm−1 on 1:1 Cu:Ni and by 36 cm−1 on copper-rich CuNi alloy. CuNi alloy formation was confirmed by X-ray absorption spectroscopy during reduction revealing a considerably lower reduction temperature of NiO in the bimetallic catalyst compared to the monometallic one. However, hydrogen chemisorption indicated that after reduction at 673 K copper was enriched at the surface of the all bimetallic catalysts, in agreement with IR spectra of adsorbed CO. In situ IR studies of methane decomposition at 773 K demonstrated that the addition of Cu to Ni strongly reduced coking occurring preferentially on nickel, while maintaining methane activation. Modification of the zirconia by ceria did not have much effect on the adsorption and reaction properties. Ceria-zirconia and zirconia supported samples exhibited very similar properties and surface chemistry. The main difference was an additional IR band of CO adsorbed on metallic copper pointing to an interaction of part of the Cu with the ceria.ISSN:1011-372XISSN:1572-879

Silica-supported isolated gallium sites as highly active, selective and stable propane dehydrogenation catalysts

Single-site gallium centers on the surface of silica are prepared via grafting of [Ga(OSi(OtBu)3)3(THF)] on SiO2–700 followed by a thermolysis step. The resulting surface species corresponds to well-defined tetra-coordinate gallium single-sites, [([triple bond, length as m-dash]SiO)3Ga(XOSi[triple bond, length as m-dash])] (X = –H or [triple bond, length as m-dash]Si) according to IR, X-ray absorption near-edge structure and extended X-ray absorption fine structure analysis. These gallium sites show high activity, selectivity and stability for propane dehydrogenation with an initial turnover frequency of 20 per h per gallium center, propylene selectivity of ≥93% and remarkable stability over 20 h. The stability of the catalyst probably results from site-isolation of the active site on a non-reducible support such as silica, diminishing facile reduction typical of Ga2O3-based catalysts.ISSN:2041-6520ISSN:2041-653

Well-Defined Silica-Supported Tungsten(IV)−Oxo Complex: Olefin Metathesis Activity, Initiation, and Role of Brønsted Acid Sites

ISSN:0002-7863ISSN:1520-512