Cryo-EM structure of a helicase loading intermediate containing ORC-Cdc6-Cdt1-MCM2-7 bound to DNA

In eukaryotes, the Cdt1-bound replicative helicase core MCM2-7 is loaded onto DNA by the ORC-Cdc6 ATPase to form a prereplicative complex (pre-RC) with an MCM2-7 double hexamer encircling DNA. Using purified components in the presence of ATP-γS, we have captured in vitro an intermediate in pre-RC assembly that contains a complex between the ORC-Cdc6 and Cdt1-MCM2-7 heteroheptamers called the OCCM. Cryo-EM studies of this 14-subunit complex reveal that the two separate heptameric complexes are engaged extensively, with the ORC-Cdc6 N-terminal AAA+ domains latching onto the C-terminal AAA+ motor domains of the MCM2-7 hexamer. The conformation of ORC-Cdc6 undergoes a concerted change into a right-handed spiral with helical symmetry that is identical to that of the DNA double helix. The resulting ORC-Cdc6 helicase loader shows a notable structural similarity to the replication factor C clamp loader, suggesting a conserved mechanism of action

Properties of Cerium (III) Fluoride Nanopowder Obtained by Pulsed Electron Beam Evaporation

The method of pulsed electron beam evaporation (PEBE) in vacuum was first used to obtain CeF3 nanopowder (NP). During NP production, a high evaporation rate of the target (∼7 g/h) and a higher percentage of NP collection (> 72%) were observed, both for fluoride and the previously obtained CeO2 oxide. The main physicochemical characteristics of NP were studied: structure, porosity, thermal stability and magnetic properties. It was found that the produced NP contains two crystalline phases: hexagonal CeF3 (95 wt%, coherent scattering regions (CSR) ≈ 8 nm) and [Ce-O-F] or [Ce-F]. The last phase is obtained only at a high temperature, which is characteristic for the used NP synthesis method. The magnetic susceptibility of CeF3 nanoparticles (NPles) coincides with the susceptibility of micron particles, indicating the potential for using such NPles as a contrast agent for tomography. High specific surface area (SSA) (CeO2–270 m2/g, CeF3 - 62 m2/g) and large pore volume (0.35–0.11 cm3/g) allow the use of NP as nanocontainers for drug delivery. © 2021.The reported study was funded by RFBR- Russian Foundation for Bacic Research; GACR-Grantova agentura Ceske Republiky (The Czech Science Foundation), project number 20-58-26002. The authors are grateful to the junior researcher of the Laboratory of Pulsed Processes of the Institute of Electrophysics Ural Branch of the Russian Academy of Sciences, K.A. Demidova for XRD analysis, Senior scientist researcher of the laboratory of pulse processes in the Institute of Electrophysics of the Ural Branch of the Russian Academy of Sciences A.M. Murzakaev for microscopic analysis

Physicochemical characterization and antioxidant properties of cerium oxide nanoparticles

Studies of the biological activity of cerium oxide nanoparticles (CONPs) show that this compound exhibits antioxidant, antitumor, antibacterial and antiviral properties. The CONPs were obtained by pulsed electron evaporation in a low-pressure gas with a specific surface area of ∼ 190 m 2 /g. Strongly-noequilibrium conditions of synthesis led to the formation of high defect structures, which makes it possible to change the Ce 3+ /Ce 4+ ions ratio and, consequently, to enhance the level of their biological activity. To analyze the content of cerium with different valences, X-ray photoelectron spectroscopy was performed. To determine the enzyme-like activity of CONPs, a chemical analysis of the interaction with hydrogen peroxide was carried out on a spectrophotometer. The results show a significant presence of Ce 3+ in CONPs and the inhibition of reactive oxygen species (ROS). The valence of the cerium atoms determines the chemical activity of CONPs; thus, in a more alkaline medium, the CONPs decrease the ROS concentration, while in the acidic medium its activity diminishes. By varying the parameters of the nanopowders obtained and achieving the optimum Ce 3+ /Ce 4+ ratio, one can produce CONPs having properties which enable the creation of pharmaceuticals for protection against ROS or for combating tumors, viruses and bacteria. © Published under licence by IOP Publishing Ltd.This work was performed within a support of the Russian Science Foundation project [16-16-04038]

Factors predicting chronic pain after open inguinal hernia repair : a regression analysis of randomized trial comparing three different meshes with three fixation methods (FinnMesh Study)

Correction: Volume: 22 Issue: 5 Pages: 819-819 DOI: 10.1007/s10029-018-1788-y WOS:000446065400016Chronic pain after inguinal hernioplasty is the foremost side-effect up to 10-30% of patients. Mesh fixation may influence on the incidence of chronic pain after open anterior mesh repairs. Some 625 patients who underwent open anterior mesh repairs were randomized to receive one of the three meshes and fixations: cyanoacrylate glue with low-weight polypropylene mesh (n = 216), non-absorbable sutures with partially absorbable mesh (n = 207) or self-gripping polyesther mesh (n = 202). Factors related to chronic pain (visual analogue scores; VAS ae 30, range 0-100) at 1 year postoperatively were analyzed using logistic regression method. A second analysis using telephone interview and patient records was performed 2 years after the index surgery. At index operation, all patient characteristics were similar in the three study groups. After 1 year, chronic inguinal pain was found in 52 patients and after 2 years in only 16 patients with no difference between the study groups. During 2 years' follow-up, three (0.48%) patients with recurrences and five (0.8%) patients with chronic pain were re-operated. Multivariate regression analysis indicated that only new recurrent hernias and high pain scores at day 7 were predictive factors for longstanding groin pain (p = 0.001). Type of mesh or fixation, gender, pre-operative VAS, age, body mass index or duration of operation did not predict chronic pain. Only the presence of recurrent hernia and early severe pain after index operation seemed to predict longstanding inguinal pain.Peer reviewe

Structural validity of the foot and ankle outcome score for orthopaedic pathologies with Rasch Measurement Theory

Publisher Copyright: © 2021 The AuthorsA B S T R A C T Background: The Foot and Ankle Outcome Score (FAOS) is one of the most frequently used patient reported outcome measures for foot and ankle conditions. The aim is to test the structural validity of the Finnish version of the FAOS using Rasch Measurement Theory. Methods: FAOS scores were obtained from 218 consecutive patients who received operative treatment for foot and ankle conditions. The FAOS data were fitted into the Rasch model and person separation index (PSI) calculated. Results: All the five subscales provided good coverage and targeting. Three subscales presented unidimensional structure. Thirty-eight of the 42 items had ordered response category thresholds. Three of the 42 items had differential item functioning towards gender. All subscales showed sufficient fit to the Rasch model. PSI ranged from 0.73 to 0.94 for the subscales. Conclusions: The Finnish version of the FAOS shows acceptable structural validity for assessing complaints in orthopaedic foot and ankle patients. (c) 2021 The Authors. Published by Elsevier Ltd on behalf of European Foot and Ankle Society. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).Peer reviewe

Production of Nanopowder of Cerium (III) Fluoride Obtained by Pulsed Electron Beam Evaporation in Vacuum

The method of pulsed electron beam evaporation in vacuum was first used to obtain CeF3 nanopowder (NP). During NP production, a high evaporation rate of the target (~ 7 g/h) and a higher percentage of NP collection (> 72%) were observed, both for fluoride and the previously obtained CeO2 oxide. It was found that the produced NP contains two crystalline phases: hexagonal CeF3 (95 wt.%, coherent scattering region ≈ 8 nm and [Ce-O-F] or [Ce-F]. The magnetic susceptibility of CeF3 nanoparticles (NPles) coincides with the susceptibility of micron particles, indicating the potential for using such NPles as a contrast agent for tomography. High specific surface area (CeO2-270 m2/g, CeF3 – 62 m2/g), large pore volume (0.35-0.11 cm3/g) allow the use of NPles as nanocontainers for drug delivery. © 2021 Institute of Physics Publishing. All rights reserved.The reported study was funded by RFBR and GACR, project number 20-58-26002

Production of Nanopowders of Bismuth Oxide Doped with Silver by Pulsed Electron Beam Evaporation in Vacuum

Various bismuth containing compounds are promising in many applications, including for creating photocatalysts based on them using a visible range of light. However, strong polymorphism (9 polymophic phases of Bi2O3), thermal instability and changes in the properties of bismuth oxide during long-term storage significantly complicate work with it. One way to increase stability and improve photocatalytic properties is by doping Bi2O3 with various metals. Ag doped Bi2O3 nanoparticles (NPs) are typically produced using chemical techniques often associated with the presence of toxic chemicals. The present paper used an environmentally friendly method of producing NPs using the method of pulsed electron beam evaporation in vacuum. The evaporation target was obtained by solid phase synthesis in an electric furnace on air using silver nitrate additives (1 and 5 wt.%).Textural, thermal and magnetic properties of the obtained NPs have been studied. Was found that the Ag-Bi2O3 NPs have a specific surface area (SSA) of 23.7 m2/g, which was almost 2 times bigger than the SSA of the pure Bi2O3 (13.2 m2/g) obtained previously. The thermal stability of the Ag-doped Bi2O3 samples was maintained to the temperature 350°C. While further heating on air took place the phase transition β → α. © 2021 Institute of Physics Publishing. All rights reserved.Authors are grateful to the research scientist of IMF UB RAS, to PhD Gaviko V.S. for XRD NPs. The reported study was funded by RFBR and GACR, project number 20-58-26002

Dissecting a complex system; a computational study of flow behavior in a single-blade pump

Paper presented at the 5th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 1-4 July, 2007.In this paper a computational, time-accurate analysis of a single-blade pump, whose flow system is characterized by highly oscillatory behavior, is presented. The study lays bare the immanent challenges present in applying CFD to such complex flow systems. Four time-accurate simulations with different modeling choices are completed in order to reveal the computational flow system's sensitivities to such decisions and obtain reliable performance predictions for experimental comparison. The time-accurate simulations consistently overpredicted the hydrodynamic performance according to expectations, but demonstrated strong dependency on particular CFD aspects: The strictness of the numerical convergence and the changes in the inflow and outflow configurations have a considerable effect on the system's flow behavior. Elevated levels of uncertainty also accompany the transient simulations.cs201

Formation of Droplets in a Heterophasic Amorphocrystalline Nanopowder Bi2O3 Produced by Pulsed Electron Beam Evaporation in Vacuum

In the present work, a mesoporous multiphase amorphous crystal nanopowder Bi2O3 with a specific surface area of up to 23 m2/g was produced by pulsed electron beam evaporation in vacuum. Influence of thermal annealing (200-500 C) of powders in air is investigated. The formation of droplets with a size of 3-5 nm on the surface of all large nanoparticles constituting the framework 3D nanopowder agglomerates was found due to extrusion of liquid bismuth from the volume during cooling. © Published under licence by IOP Publishing Ltd.The study was carried out with the financial support of RFFI and the Czech Science Foundation as part of scientific project No. 20-58-26002