ЭКСТРАКЦИОННО-ФЛУОРИМЕТРИЧЕСКОЕ ОПРЕДЕЛЕНИЕ ХЛОРОФИЛЛА «А» В ПРИРОДНЫХ ВОДАХ

The assessment methods of chlorophyll «а» in the natural waters have been analyzed. This pigment of phytoplankton is the main indicator of the primary bioproductivity and trophicity of the reservoir.  The key spectrometric methods of determination were compared, and their advantages and disadvantages were discussed.  The application features of different types of spectrometric determination of the analyte from classical spectrophotometric methods to remote sensing of water bodies were considered.  The preference was shown for the determination of chlorophyll by the fluorescent methods, which were used in different implementation variations.  The method of extraction-fluorescent determination of chlorophyll «а» was substantiated and implemented after the chlorophyll extraction from the water with chloroform and measuring the fluorescence intensity at λexc = 418 nm and λlum = 675 nm.  The results of the chlorophyll «а» determination were compared using the standardized spectrophotometric and the developed techniques for the model and real water samples.  It was educed that in the area of low concentrations of chlorophyll «а» (0.05 μg of analyte in 1000 cm3 of water) the analytical signal was recorded only by the fluorimetric method, while in the area of higher concentrations (0.2 μg of analyte in 1000 cm3 of water) the standardized spectrophotometric method produced the overestimated results.  The developed method for the extraction-fluorimetric determination of chlorophyll «а» in the natural waters (both fresh and marine) was metrologically certified and put into the register of the Federal Information Fund for ensuring the uniformity of measurements.Key words: chlorophyll «а» , extraction - fluorimetric determination, trophicity of the reservoirDOI: http://dx.doi.org/10.15826/analitika.2019.23.3.001(Russian)Z. A. Temerdasheva1, L. F. Pavlenko2, Ya. S. Ermakova1,2, I. G. Korpakova1,             B. D. Eletskii1 1Department of Chemistry and High Technology, Kuban State University, Krasnodar, 350040, Russian Federation2Azov-Black Sea branch of VNIRO (“AzNIIRKH”), Rostov-on-Don, 344002, Russian FederationВ статье проводится анализ методов определения хлорофилла «а» в природных водах – основного пигмента фитопланктона, являющегося индикатором первичной биопродуктивности и трофности водоема. Приводится сравнительная характеристика спектрометрических методов определения, их достоинства и недостатки. Обсуждаются особенности применения различных видов спектрометрического определения аналита: от классических спектрофотометрических до методов дистанционного зондирования водоемов. Показана предпочтительность определения хлорофилла флуоресцентными методами, которые используются в различных вариантах реализации. Обоснована и реализована методика экстракционно-флуоресцентного определения хлорофилла «а» после экстракции его из воды хлороформом и измерении интенсивности флуоресценции при λвозб = 418 нм и λлюм = 675 нм. Проведено сравнение результатов определения хлорофилла «а» стандартизированной спектрофотометрической и разработанной методиками на модельных и реальных пробах воды.  Показано, что в области низких концентраций хлорофилла «а» (0,05 мкг аналита в 1000 см3 воды) аналитический сигнал регистрируется только флуориметрическим методом, а в области более высоких концентраций (0.2 мкг аналита в 1000 см3 воды) спектрофотометрическая стандартизированная методика дает завышенные результаты. Разработанная методика экстракционно-флуориметрического определения хлорофилла «а» в природных водах (пресных и морских) метрологически аттестована и внесена в реестр Федерального информационного фонда по обеспечению единства измерений.Ключевые слова. Хлорофилл «а» , экстракционно-флуориметрическое определение, трофность водоемов.DOI: http://dx.doi.org/10.15826/analitika.2019.23.3.00

On the Cauchy Problem for the Korteweg-de Vries Equation with Steplike Finite-Gap Initial Data I. Schwartz-Type Perturbations

We solve the Cauchy problem for the Korteweg-de Vries equation with initial conditions which are steplike Schwartz-type perturbations of finite-gap potentials under the assumption that the respective spectral bands either coincide or are disjoint.Comment: 29 page

Heart rate variability and cortisol levels in school-age children with different cognitive tests

Background. An urgent task of age-related physiology is to study the functional state of the body of school-age children in cognitive activity due to the large academic load and the use of information and computer technologies in the educational process to identify the characteristics of the reactivity of the body of students when performing cognitive load of various types, including on electronic devices, is necessary for the organization of the school educational environment.The aim. To assess the nature of vegetative, cardiovascular and hormonal reactivity in cognitive load of various types in school-age children.Materials and methods. By methods of heart rate variability analysis, electrocardiography, tonometry and enzyme immunoassay of cortisol in saliva, 117 school-age children were examined while performing cognitive load of various types.Results. There is a change in heart rate variability indicators while performing cognitive load. Oral counting causes an increase in sympathetic influences on the heart rate with a decrease in parasympathetic activity, as well as a shift in the vagosympathetic balance. Operation on the electronic devices causes a decrease in the total power density of the spectrum and an increase in the index of low-frequency and highfrequency vibrations ratio due to a decrease in parasympathetic activity. Two types of reaction were revealed: type I – an increase in the concentration of cortisol in saliva, an increase in sympathetic effects on Heart rate with a simultaneous decrease in parasympathetic activity (counting), a decrease in the total power of the spectrum density (laptop), a decrease in parasympathetic activity (tablet). Type II – a decrease in hormone levels and a decrease in very low-frequency vibrations and parasympathetic activity, regardless of the type of load presentedConclusion. The results obtained indicate that the nature of the reactivity of heart rate indicators and the stress hormone cortisol in students depends not so much on which electronic device it is performed on, but on the type of cognitive load

Placement and orientation of individual DNA shapes on lithographically patterned surfaces

Artificial DNA nanostructures show promise for the organization of functional materials to create nanoelectronic or nano-optical devices. DNA origami, in which a long single strand of DNA is folded into a shape using shorter 'staple strands', can display 6-nm-resolution patterns of binding sites, in principle allowing complex arrangements of carbon nanotubes, silicon nanowires, or quantum dots. However, DNA origami are synthesized in solution and uncontrolled deposition results in random arrangements; this makes it difficult to measure the properties of attached nanodevices or to integrate them with conventionally fabricated microcircuitry. Here we describe the use of electron-beam lithography and dry oxidative etching to create DNA origami-shaped binding sites on technologically useful materials, such as SiO_2 and diamond-like carbon. In buffer with ~ 100 mM MgCl_2, DNA origami bind with high selectivity and good orientation: 70–95% of sites have individual origami aligned with an angular dispersion (±1 s.d.) as low as ±10° (on diamond-like carbon) or ±20° (on SiO_2)

A large scale hearing loss screen reveals an extensive unexplored genetic landscape for auditory dysfunction

The developmental and physiological complexity of the auditory system is likely reflected in the underlying set of genes involved in auditory function. In humans, over 150 non-syndromic loci have been identified, and there are more than 400 human genetic syndromes with a hearing loss component. Over 100 non-syndromic hearing loss genes have been identified in mouse and human, but we remain ignorant of the full extent of the genetic landscape involved in auditory dysfunction. As part of the International Mouse Phenotyping Consortium, we undertook a hearing loss screen in a cohort of 3006 mouse knockout strains. In total, we identify 67 candidate hearing loss genes. We detect known hearing loss genes, but the vast majority, 52, of the candidate genes were novel. Our analysis reveals a large and unexplored genetic landscape involved with auditory function

EMIC wave events during the four GEM QARBM challenge intervals

This paper presents observations of EMIC waves from multiple data sources during the four GEM challenge events in 2013 selected by the GEM “Quantitative Assessment of Radiation Belt Modeling” focus group: March 17‐18 (Stormtime Enhancement), May 31‐June 2 (Stormtime Dropout), September 19‐20 (Non‐storm Enhancement), and September 23‐25 (Non‐storm Dropout). Observations include EMIC wave data from the Van Allen Probes, GOES, and THEMIS spacecraft in the near‐equatorial magnetosphere and from several arrays of ground‐based search coil magnetometers worldwide, as well as localized ring current proton precipitation data from low‐altitude POES spacecraft. Each of these data sets provides only limited spatial coverage, but their combination shows consistent occurrence patterns and reveals some events that would not be identified as significant using near‐equatorial spacecraft alone. Relativistic and ultrarelativistic electron flux observations, phase space density data, and pitch angle distributions based on data from the REPT and MagEIS instruments on the Van Allen Probes during these events show two cases during which EMIC waves are likely to have played an important role in causing major flux dropouts of ultrarelativistic electrons, particularly near L* ~ 4.0. In three other cases identifiable smaller and more short‐lived dropouts appeared, and in five other cases these waves evidently had little or no effect

Predicting Functional Alternative Splicing by Measuring RNA Selection Pressure from Multigenome Alignments

High-throughput methods such as EST sequencing, microarrays and deep sequencing have identified large numbers of alternative splicing (AS) events, but studies have shown that only a subset of these may be functional. Here we report a sensitive bioinformatics approach that identifies exons with evidence of a strong RNA selection pressure ratio (RSPR) —i.e., evolutionary selection against mutations that change only the mRNA sequence while leaving the protein sequence unchanged—measured across an entire evolutionary family, which greatly amplifies its predictive power. Using the UCSC 28 vertebrate genome alignment, this approach correctly predicted half to three-quarters of AS exons that are known binding targets of the NOVA splicing regulatory factor, and predicted 345 strongly selected alternative splicing events in human, and 262 in mouse. These predictions were strongly validated by several experimental criteria of functional AS such as independent detection of the same AS event in other species, reading frame-preservation, and experimental evidence of tissue-specific regulation: 75% (15/20) of a sample of high-RSPR exons displayed tissue specific regulation in a panel of ten tissues, vs. only 20% (4/20) among a sample of low-RSPR exons. These data suggest that RSPR can identify exons with functionally important splicing regulation, and provides biologists with a dataset of over 600 such exons. We present several case studies, including both well-studied examples (GRIN1) and novel examples (EXOC7). These data also show that RSPR strongly outperforms other approaches such as standard sequence conservation (which fails to distinguish amino acid selection pressure from RNA selection pressure), or pairwise genome comparison (which lacks adequate statistical power for predicting individual exons)

ЗАБОЛЕВАЕМОСТЬ ЭНТЕРОВИРУСНОЙ ИНФЕКЦИЕЙ И ОСОБЕННОСТИ ЦИРКУЛЯЦИИ НЕПОЛИОМИЕЛИТНЫХ ЭНТЕРОВИРУСОВ НА НЕКОТОРЫХ ТЕРРИТОРИЯХ РОССИИ В 2017 ГОДУ

Aim: Characteristics of enterovirus infection morbidity and study of peculiarities of enterovirus circulation on some territories of Russia in 2017. Materials and methods: We investigated more than 5000 samples from the patients with enterovirus infection. The isolation and identification of enteroviruses were conducted by virological method and by partial sequencing of the genome region VP1. Phylogenic trees were constructed according to the method of Bayesian Monte Carlo Markov Chain. Results: Epidemic process and clinical picture of enterovirus infection were not the same on different territories. Peculiarities of the circulation of different types of enteroviruses on the territories were also different. In Saratov region 65% of cases were represented by enterovirus meningitis. In Murmansk region and in the Komi Republic enterovirus infection with exanthema prevailed, 95% and 60% correspondingly. In Saratov region enterovirus ECHO18 was the etiological agent of enterovirus meningitis. In Murmansk region and in the Komi Republic the cases were connected mainly with Coxsackieviruses A6. The strains of enterovirus ECHO18 were distributed to three clusters. The strains which provoked enterovirus meningitis in Saratov region belonged to cluster 3, they were formed separately from other strains of this enterovirus type and differed from the stains of ECHO18 which circulated in the North-West of Russia. The strains of Coxsackieviruses A6 identified in the North-West of Russia belonged to three sub-genotypes 5, 6, 8 of pandemic genotype of CoxsackievirusesA6. The majority of the strains belonged to sub-genotypes 6 and 8 which in 2017 dominated in the structure of Coxsackieviruses A6 in the North-West of Russia and in Russia. Conclusion: Epidemic peaks of enterovirus infection represented by different clinical forms of the disease were provoked by different types of enteroviruses. Enterovirus ECHO18 was the etiological agent of enterovirus meningitis. The main etiological factors of enterovirus infection with exanthema were Coxsackieviruses A6 of different sub-genotypes.Цель: характеристика заболеваемости энтеровирусной инфекцией и изучение особенностей циркуляции неполиомиелитных энтеровирусов на ряде территорий России в 2017 г. Материалы и методы: исследовано более 5000 проб фекалий от больных энтеровирусной инфекцией. Выделение и идентификацию энтеровирусов проводили вирусологическим методом и путём частичного секвенирования области генома VP1. Филогенетические деревья были построены методом Bayesian Monte Carlo Markov Chain. Результаты: течение эпидемического процесса и клинические проявления энтеровирусной инфекции на разных территориях отличались. Особенности циркуляции энтеровирусов разных типов на территориях также были разными. В Саратовской области 65% заболеваний были представлены энтеровирусным менингитом. В Мурманской области и в Республике Коми преобладали экзантемные формы энтеровирусной инфекции, составившие 95% и 60% соответственно. В Саратовской области этиологическим фактором энтеровирусного менингита оказался энтеровирус ЕСНО 18. В Мурманской области и в Республике Коми заболевания были обусловлены в основном Coxsackievirus А6. Штаммы энтеровируса ЕСНО 18 распределились по трем кластерам. Штаммы, обусловившие заболевания энтеровирусным менингитом в Саратовской области, вошли в кластер 3, они сформировались отдельно от штаммов этого типа вируса и отличались от штаммов ЕСНО18, которые циркулировали на северо-западе России. Штаммы вируса Coxsackievirus А6, идентифицированные на северо-западе России, относились к трем субгенотипам пандемического генотипа вируса Coxsackievirus А6 – 5, 6 и 8. Большинство штаммов относились к субгенотипам 6 и 8, которые в 2017 г. доминировали в структуре Coxsackieviruses А6 на северо-западе России и в Российской Федерации в целом. Заключение: эпидемические подъемы заболеваемости энтеровирусной инфекцией, представленной различными клиническими формами, были обусловлены разными типами энтеровирусов. Этиологическим агентом энтеровирусного менингита были энтеровирусы ЕСНО 18. Основным этиологическим фактором экзантемных форм заболевания были Coxsackieviruses A6 разных субгенотипов