Review of analytical instruments for EEG analysis

Since it was first used in 1926, EEG has been one of the most useful instruments of neuroscience. In order to start using EEG data we need not only EEG apparatus, but also some analytical tools and skills to understand what our data mean. This article describes several classical analytical tools and also new one which appeared only several years ago. We hope it will be useful for those researchers who have only started working in the field of cognitive EEG

Super rogue waves in simulations based on weakly nonlinear and fully nonlinear hydrodynamic equations

The rogue wave solutions (rational multi-breathers) of the nonlinear Schrodinger equation (NLS) are tested in numerical simulations of weakly nonlinear and fully nonlinear hydrodynamic equations. Only the lowest order solutions from 1 to 5 are considered. A higher accuracy of wave propagation in space is reached using the modified NLS equation (MNLS) also known as the Dysthe equation. This numerical modelling allowed us to directly compare simulations with recent results of laboratory measurements in \cite{Chabchoub2012c}. In order to achieve even higher physical accuracy, we employed fully nonlinear simulations of potential Euler equations. These simulations provided us with basic characteristics of long time evolution of rational solutions of the NLS equation in the case of near breaking conditions. The analytic NLS solutions are found to describe the actual wave dynamics of steep waves reasonably well.Comment: under revision in Physical Review

Evidence for the extracellular delivery of influenza NS1 protein

We constructed a reporter influenza A/Puerto Rico/8/1934 virus expressing truncated 124aa N-terminal NS1 protein fused to a luciferase reporter sequence (NanoLuc) without signal peptide. The reproduction activity of the vector correlated well with the luminescent activity in the lysates of infected cell cultures or mouse respiratory organ suspensions. Surprisingly, we found that luciferase enzymatic activity was present not only in the intracellular compartments but also in cell culture supernatants as well as in the sera or bronchiolar lavages of infected mice. This fact allowed us to formulate a working hypothesis about the extracellular delivery mechanism of the NS1 protein. To test this idea, we conducted co-transfection experiments in Vero cells with different combinations of plasmids encoding influenza genomic segments and chimeric NS1-NanoLuc encoding plasmid. We found that the emergence of the luciferase reporter in the extracellular compartment was promoted by the formation of the ribonucleoprotein complex (RNP) from the co-transfection of plasmids expressing PB1, PB2, PA, and NP proteins. Therefore, influenza NS1 protein may be delivered to the extracellular compartment together with the nascent RNP complexes during the maturation of virus particles.We constructed a reporter influenza A/Puerto Rico/8/1934 virus expressing truncated 124aa N-terminal NS1 protein fused to a luciferase reporter sequence (NanoLuc) without signal peptide. The reproduction activity of the vector correlated well with the luminescent activity in the lysates of infected cell cultures or mouse respiratory organ suspensions. Surprisingly, we found that luciferase enzymatic activity was present not only in the intracellular compartments but also in cell culture supernatants as well as in the sera or bronchiolar lavages of infected mice. This fact allowed us to formulate a working hypothesis about the extracellular delivery mechanism of the NS1 protein. To test this idea, we conducted co-transfection experiments in Vero cells with different combinations of plasmids encoding influenza genomic segments and chimeric NS1-NanoLuc encoding plasmid. We found that the emergence of the luciferase reporter in the extracellular compartment was promoted by the formation of the ribonucleoprotein complex (RNP) from the co-transfection of plasmids expressing PB1, PB2, PA, and NP proteins. Therefore, influenza NS1 protein may be delivered to the extracellular compartment together with the nascent RNP complexes during the maturation of virus particles

Impact of magnetic storms on the global TEC distribution

The study is focused on the analysis of total electron content (TEC) variations during six geomagnetic storms of different intensity: from Dstmin = −46&thinsp;nT to Dstmin = −223&thinsp;nT. The values of TEC deviations from its 27-day median value (δTEC) were calculated during the periods of the storms along three meridians: American, Euro-African and Asian-Australian. The following results were obtained. For the majority of the storms almost simultaneous occurrence of δTEC maximums was observed along all three meridians at the beginning of the storm. The transition from a weak storm to a superstorm (the increase of magnetic activity) almost does not affect the intensity of the δTEC maximum. The seasonal effect was most pronounced along the Asian-Australian meridian, less often along the Euro-African meridian and was not revealed along the American meridian. Sometimes the seasonal effect can penetrate to the opposite hemisphere. The character of average δTEC variations for the intense storms was confirmed by GOES satellite data. Though there are some common features of TEC variation revealed during each storm phase, in general no clear dependence of TEC responses on the storm phases was found: the effects were different during each storm at different locations. The behavior of the correlation coefficient (R) between δTEC values along the three meridians was analyzed for each storm. In general, R &gt; 0.5 between δTEC values averaged along each meridian. This result is new. The possible reasons for the exceptions (when R &lt; 0.5) were provided: the complexity of phenomena during the intense storms and discordance in local time of the geomagnetic storm beginning along different meridians. Notwithstanding the complex dependence of R on the intensity of magnetic disturbance, in general R decreased with the growth of storm intensity.</p

Catalytic molecularly imprinted polymer membranes: Development of the biomimetic sensor for phenols detection

Portable biomimetic sensor devices for the express control of phenols content in water were developed. The synthetic binding sites mimicking active site of the enzyme tyrosinase were formed in the structure of free-standing molecularly imprinted polymer membranes. Molecularly imprinted polymer membranes with the catalytic activity were obtained by co-polymerization of the complex Cu (II)–catechol–urocanic acid ethyl ester with (tri)ethyleneglycoldimethacrylate, and oligourethaneacrylate. Addition of the elastic component oligourethaneacrylate provided formation of the highly cross-linked polymer with the catalytic activity in a form of thin, flexible, and mechanically stable membrane. High accessibility of the artificial catalytic sites for the interaction with the analyzed phenol molecules was achieved due to addition of linear polymer (polyethyleneglycol Mw 20,000) to the initial monomer mixture before the polymerization. As a result, typical semi-interpenetrating polymer networks (semi-IPNs) were formed. The cross-linked component of the semi-IPN was represented by the highly cross-linked catalytic molecularly imprinted polymer, while the linear one was represented by polyethyleneglycol Mw 20,000. Extraction of the linear polymer from the fully formed semi-IPN resulted in formation of large pores in the membranes’ structure. Concentration of phenols in the analyzed samples was detected using universal portable device oxymeter with the oxygen electrode in a close contact with the catalytic molecularly imprinted polymer membrane as a transducer. The detection limit of phenols detection using the developed sensor system based on polymers–biomimics with the optimized composition comprised 0.063 mM, while the linear range of the sensor comprised 0.063–1 mM. The working characteristics of the portable sensor devices were investigated. Storage stability of sensor systems at room temperature comprised 12 months (87%). As compared to traditional methods of phenols detection the developed sensor system is characterized by simplicity of operation, compactness, an

Mutations designed to modify the NS gene mRNA secondary structure affect influenza A pathogenicity in vivo

The influenza A virus genome consists of eight segments of negative-sense RNA that encode up to 18 proteins. During the process of viral replication, positive-sense (+)RNA (cRNA) or messenger RNA (mRNA) is synthesized. Today, there is only a partial understanding of the function of several secondary structures within vRNA and cRNA promoters, and splice sites in the M and NS genes. The most precise secondary structure of (+)RNA has been determined for the NS segment of influenza A virus.  The influenza A virus NS gene features two regions with a conserved mRNA secondary structure located near splice sites. Here, we compared 4 variants of the A/Puerto Rico/8/1934 strain featuring different combinations of secondary structures at the NS segment (+)RNA regions 82-148 and 497-564. We found that RNA structures did not affect viral replication in cell culture. However, one of the viruses demonstrated lower NS1 and NEP expression levels during early stage cell infection as well as reduced pathogenicity in mice compared to other variants. In particular, this virus is characterized by an RNA hairpin in the 82-148 region and a stable hairpin in the 497-564 region.The influenza A virus genome consists of eight segments of negative-sense RNA that encode up to 18 proteins. During the process of viral replication, positive-sense (+)RNA (cRNA) or messenger RNA (mRNA) is synthesized. Today, there is only a partial understanding of the function of several secondary structures within vRNA and cRNA promoters, and splice sites in the M and NS genes. The most precise secondary structure of (+)RNA has been determined for the NS segment of influenza A virus.  The influenza A virus NS gene features two regions with a conserved mRNA secondary structure located near splice sites. Here, we compared 4 variants of the A/Puerto Rico/8/1934 strain featuring different combinations of secondary structures at the NS segment (+)RNA regions 82-148 and 497-564. We found that RNA structures did not affect viral replication in cell culture. However, one of the viruses demonstrated lower NS1 and NEP expression levels during early stage cell infection as well as reduced pathogenicity in mice compared to other variants. In particular, this virus is characterized by an RNA hairpin in the 82-148 region and a stable hairpin in the 497-564 region

Aromaticity in a Surface Deposited Cluster: Pd4_4 on TiO2_2 (110)

We report the presence of \sigma-aromaticity in a surface deposited cluster, Pd$_4$ on TiO$_2$ (110). In the gas phase, Pd$_4$ adopts a tetrahedral structure. However, surface binding promotes a flat, \sigma-aromatic cluster. This is the first time aromaticity is found in surface deposited clusters. Systems of this type emerge as a promising class of catalyst, and so realization of aromaticity in them may help to rationalize their reactivity and catalytic properties, as a function of cluster size and composition.Comment: 4 pages, 3 figure

H5N1 influenza vaccine quality is affected by hemagglutinin conformational stability

Since 1997, highly pathogenic H5N1 avian influenza viruses have circulated in wild and domestic birds and sporadically have infected humans. Conventional inactivated vaccines made from these viruses were shown to have decreased HA content and immunogenicity compared to seasonal preparations. We assumed that the high pH threshold (5.6-6.0) known for the HA conformational change (pH of fusion or activation) of avian highly pathogenic influenza viruses resulted in the low stability of native HA conformation and affected the vaccine quality. The 58Lys→Ile mutation introduced into the HA2 subunit of the HA of A/chicken/Kurgan/5/05 (H5N1) virus decreased the pH threshold of the HA activation. The mutant virus demonstrated increased HA stability toward acidic pH and elevated temperature, decreased binding efficiency to the monoclonal antibody IIF4 that recognizes the HA low pH form, and increased HA resistance to trypsin digestion. Virus with modified HA was less susceptible to freezing stress and showed an increased content of immunocompetent HA in inactivated vaccine preparation compared to the analogous virus with original HA. Therefore, we have shown a way to increase the quality of inactivated vaccines made from highly pathogenic avian influenza viruses.Since 1997, highly pathogenic H5N1 avian influenza viruses have circulated in wild and domestic birds and sporadically have infected humans. Conventional inactivated vaccines made from these viruses were shown to have decreased HA content and immunogenicity compared to seasonal preparations. We assumed that the high pH threshold (5.6-6.0) known for the HA conformational change (pH of fusion or activation) of avian highly pathogenic influenza viruses resulted in the low stability of native HA conformation and affected the vaccine quality. The 58Lys→Ile mutation introduced into the HA2 subunit of the HA of A/chicken/Kurgan/5/05 (H5N1) virus decreased the pH threshold of the HA activation. The mutant virus demonstrated increased HA stability toward acidic pH and elevated temperature, decreased binding efficiency to the monoclonal antibody IIF4 that recognizes the HA low pH form, and increased HA resistance to trypsin digestion. Virus with modified HA was less susceptible to freezing stress and showed an increased content of immunocompetent HA in inactivated vaccine preparation compared to the analogous virus with original HA. Therefore, we have shown a way to increase the quality of inactivated vaccines made from highly pathogenic avian influenza viruses

Statistical analysis of the spatial distribution of impurities in the snow cover in the vicinity of copper mine in the Middle Ural of Russia

Statistical analysis of the monitoring data of industrial enterprises influence zones is an important part of the researches related to natural environment changes. In present study, a cluster analysis of the elemental composition of the snow cover in the vicinity of a copper mine was carried out. The data were obtained as a result of the chemical analysis of the snow samples collected during annual environmental monitoring in the region of Rezh town (the Middle Ural of Russia), where Safyanovsky Copper Mine and Rezhevsky Nickel Plant are located. The elements identified by chemical analysis were grouped according to the strength of the correlation bond. The cluster analysis of these groups made it possible to identify and separate the influence zones of the Plant, Mine and other industrial objects located in the area. The obtained results became the basis for adjusting the snow cover monitoring scheme. © 2018 Author(s).The research is supported by the project of the Ural Branch of Russian Academy of Sciences No. 18-5-2345-56