Biological Impact of γ-Fe2O3 Magnetic Nanoparticles Obtained by Laser Target Evaporation: Focus on Magnetic Biosensor Applications

The biological activity of γ-Fe2O3 magnetic nanoparticles (MNPs), obtained by the laser target evaporation technique, was studied, with a focus on their possible use in biosensor applications. The biological effect of the MNPs was investigated in vitro on the primary cultures of human dermal fibroblasts. The effects of the MNPs contained in culture medium or MNPs already uptaken by cells were evaluated for the cases of the fibroblast’s proliferation and secretion of cytokines and collagen. For the tests related to the contribution of the constant magnetic field to the biological activity of MNPs, a magnetic system for the creation of the external magnetic field (having no commercial analogues) was designed, calibrated, and used. It was adapted to the size of standard 24-well cell culture plates. At low concentrations of MNPs, uptake by fibroblasts had stimulated their proliferation. Extracellular MNPs stimulated the release of pro-inflammatory cytokines (Interleukin-6 (IL-6) and Interleukin-8 (IL-8) or chemokine (C-X-C motif) ligand 8 (CXCL8)) in a concentration-dependent manner. However, the presence of MNPs did not increase the collagen secretion. The exposure to the uniform constant magnetic field (H ≈ 630 or 320 Oe), oriented in the plane of the well, did not cause considerable changes in fibroblasts proliferation and secretion, regardless of presence of MNPs. Statistically significant differences were detected only in the levels of IL-8/CXCL8 release.The study was supported by the program of the Ministry of Health of the Russian Federation (project 121032300335-1). This work was financially supported, in part, by the Ministry of Science and Higher Education of the RF (grant FEUZ-2020-0051) (G.Yu. Melnikov) and University of the Basque Country Research Groups Funding (grant IT1245-19) (G.V. Kurlyandskaya)

Mechanical, Electrical and Magnetic Properties of Ferrogels with Embedded Iron Oxide Nanoparticles Obtained by Laser Target Evaporation: Focus on Multifunctional Biosensor Applications

Hydrogels are biomimetic materials widely used in the area of biomedical engineering and biosensing. Ferrogels (FG) are magnetic composites capable of functioning as magnetic field sensitive transformers and field assisted drug deliverers. FG can be prepared by incorporating magnetic nanoparticles (MNPs) into chemically crosslinked hydrogels. The properties of biomimetic ferrogels for multifunctional biosensor applications can be set up by synthesis. The properties of these biomimetic ferrogels can be thoroughly controlled in a physical experiment environment which is much less demanding than biotests. Two series of ferrogels (soft and dense) based on polyacrylamide (PAAm) with different chemical network densities were synthesized by free-radical polymerization in aqueous solution with N, N'-methylene-diacrylamide as a cross-linker and maghemite Fe2O3 MNPs fabricated by laser target evaporation as a filler. Their mechanical, electrical and magnetic properties were comparatively analyzed. We developed a giant magnetoimpedance (MI) sensor prototype with multilayered FeNi-based sensitive elements deposited onto glass or polymer substrates adapted for FG studies. The MI measurements in the initial state and in the presence of FG with different concentrations of MNPs at a frequency range of 1-300 MHz allowed a precise characterization of the stray fields of the MNPs present in the FG. We proposed an electrodynamic model to describe the MI in multilayered film with a FG layer based on the solution of linearized Maxwell equations for the electromagnetic fields coupled with the Landau-Lifshitz equation for the magnetization dynamics.This work was supported in part within the framework of the state task of the Ministry of Education and Science of Russia 3.6121.2017/8.9; RFBR grants 16-08-00609-a, 18-08-00178, and by the ACTIMAT ELKARTEK grant of the Basque Country Government. Selected studies were made at SGIKER Common Services of UPV-EHU and URFU Common Services. We thank I.V. Beketov, A.A. Chlenova, S.O. Volchkov, V.N. Lepalovskij, A.M. Murzakaev and A.A. Svalova for special support

Nightfire method to track volcanic eruptions from multispectral satellite images

This work presents the first results of an application of the Nightfire hotspot algorithm towards volcano activity detection. Nightfire algorithm have been developed to play along with a Suomi-NPP polar satellite launched in 2011, which has a new generation multispectral VIIRS thermal sensor on board, to detect gas flares related to the upstream and downstream production of oil and natural gas. Simultaneously using of nighttime data in SWIR, MWIR, and LWIR sensor bands the algorithm is able to estimate the hotspot temperature, size and radiant heat. Four years of non-filtered observations have been accumulated in a spatio-temporal detection database, which currently totals 125 GB in size. The first part of this work presents results of retrospective cross-match of the detection database with the publicly available observed eruptions databases. The second part discusses how an approximate 3D shape of a lava lake could be modeled based on the apparent source size and satellite zenith angle. The third part presents the results of fusion Landsat-8 and Himawari-8 satellites data with the VIIRS Nightfire for several active volcanoes

VIIRS Nightfire Remote Sensing Volcanoes

Satellite based remote sensing of active volcanoes has been performed in various forms since 1965. Compared to “on the ground” observations it lets data to be gathered globally at regular pace for long periods of time without the need for local maintenance. Currently existing publicly available volcanoes thermal activity monitoring systems rely on the detection algorithms narrowly specified for volcanoes temperature ranges and operate using the data from previous generation of sensors, which is supported with non-reserved constellation of two satellites. The presented work proposes pipeline (the sequence of actions) based on the clustering of the data received from the Nightfire thermal anomalies detection algorithm, which is not focused on the specific type of infrared sources. Pipeline has been tested on Kamchatka’s region 2016 year dataset and proved to produce sound results corresponding to manual observations

To the issue about the purpose and objectives the USA National initiative for cybersecurity education

In the current year, Russia entered a three-year transitional period for the implementation of professional standards designed to replace the traditional regulations of the Unified Qualification Handbook (UQH) for the positions of executives, specialists and employees. Several professional standards have been approved for the field of staffing of information security. However, from the higher school point of view, the existing variety of approved professional standards can hardly be used as a normative basis for the improvement and development of the existing system of educational standards in the information security area, although such an obvious conceptual task was set in the framework of the transition from UQH to professional standards. This paper analyses foreign experience in solving this problem using rather impressive example of the United States. A systematic study of the labor (personnel) resources structure in the cybersecurity field was carried on within the framework of the national initiative for cybersecurity education, which is proposed as a fundamental reference resource. That resource can be used to guide the various category users, including educational organizations, to solve their tasks of providing labor resources in the field of cybersecurity. The cybersecurity workforce framework (CWF) components include such categories as specialty areas, work roles, knowledge, skills, abilities and tasks (performed for any kind of work). The paper analyzes the presented CWF, its content, as well as its important role in harmonizing the Russian educational standards in the field of cybersecurity

Selected features of morpho-functional reactions of eukaryotic microorganisms grown in the presence of maghemite iron oxide nanoparticles obtained by laser target evaporation

Biological activity of iron introduced into nutrient medium as a suspension of iron oxide nanoparticles (MNPs) synthesized by the laser target evaporation was investigated. Exophiala nigrum (E. nigrum) eukaryotes were grown either in the presence or in absence of MNPs. De-aggregated suspensions of Fe2.75O4 MNPs were added in concentrations of 1 to 104 maximum permissive dose (MPD, being 0.3 mg/L of Fe ions in water). Cells were exposed for 24 to 96 hours periods and then plated onto a solid medium. The effect of MNPs was evaluated by the change in the number of cells during exposure and the number and morphology of the colonies. For 1-10 MPD yeast showed unaltered characteristics. For 100 or 1000 MPD for 72 hours of exposure and above the number of cells increases up to 30 times in comparison with the control. A pronounced stimulating effect was revealed at 104 MPD of iron. A significant excess of the number of cells was observed for the first day. At exposures of 72 and 96 hours the differences in the number of cells in comparison with the control were 11 and 30 times, respectively. A change in the colonies morphology was observed at 100 MPD concentration

Methodological aspects of small iron concentrations determination in black yeasts grown in the presence of iron oxide nanoparticles

Nonpathogenic Exophiala nigrum (black yeasts) unicelular organisms of the Baikal Lake were used as a model system for determination of small iron concentrations in the samples grown without or with controlled amount of maghemite nanoparticles (MNPs) in nutrient. MNPs were produced by the electrophysical laser target evaporation technique. Electrostatically stabilized suspensions were prepared using sodium citrate solutions in distilled water. We assumed that one maximum permissive dose of ionic iron in water 1 MPD is equal to 0.3 mg/L. For biological experiments Saburo liquid nutrient medium was prepared with iron concentrations of 0, 102, 103 and 104 MPD. One ml of E. Nigrum cell suspension was added to Saburo liquid nutrient for 24 hours exposure. Followed by sowing onto a solid agar Saburo for 30 days colonies grows. Biosamples for electron microscopy, magnetic and total reflection X-ray fluorescence spectroscopy measurements were collected simultaneously. We were able to comparatively analyze the trace concentrations of iron in the yeast of the order of 10 ppm for control group and 600 ppm for the group grown in the presence of 104 MPD of iron