Following the discovery of the gravitational-wave source GW170817 by three Laser Interferometer Gravitational-wave Observatory (LIGO)/Virgo antennae (Abbott et al., 2017a), the MASTER Global Robotic ...Net telescopes obtained the first image of the NGC 4993 host galaxy. An optical transient, MASTER OTJ130948.10-232253.3/SSS17a was later found, which appears to be a kilonova resulting from the merger of two neutron stars (NSs). Here we describe this independent detection and photometry of the kilonova made in white light, and in B, V, and R filters. We note that the luminosity of this kilonova in NGC 4993 is very close to those measured for other kilonovae possibly associated with gamma-ray burst (GRB) 130603 and GRB 080503.
Abstract
This article presents the early results of synchronous multiwavelength observations of one of the brightest gamma-ray bursts (GRBs) GRB 160625B with the detailed continuous fast optical ...photometry of its optical counterpart obtained by MASTER and with hard X-ray and gamma-ray emission, obtained by the Lomonosov and Konus-Wind spacecraft. The detailed photometry led us to detect the quasi-periodical emission components in the intrinsic optical emission. As a result of our analysis of synchronous multiwavelength observations, we propose a three-stage collapse scenario for this long and bright GRB. We suggest that quasiperiodic fluctuations may be associated with forced precession of a self-gravitating rapidly rotating superdense body (spinar), whose evolution is determined by a powerful magnetic field. The spinar’s mass allows it to collapse into a black hole at the end of evolution.
In this work, the analytical approach to fast diagnostics of gynecological conditions based on the screening of volatile compounds in cervical mucus using a portable electronic nose system was ...developed for the first time. The highly sensitive electronic nose system based on seven mass-sensitive piezo-sensors with nanostructured modifiers of electrodes was utilized for the detection of highly volatile biomolecules (amines, ketones, alcohols, aldehydes, carbonic acids) in cervical mucus samples directly in a consulting room. We were solving the task to develop a model for rapid identification of patients with gynecologic inflammation diseases according to results from gaseous sensors or a single sensor scanning of a mixture composition of volatile molecules released by mucus. Whereupon we propose the following group ranking as "conditionally healthy", "remission", and "inflammation/infection". Preliminary, by individual substances we estimated selectivity and kinetic features of sorption-desorption processes on the selected array of stabilized gaseous sensors. According to the groups of compounds the detection limit by an array of sensors is 20 ррm for ketones by acetone, 10 ppm for alcohols by ethanol, for arenas 2 ppm by toluene, 20 ppb by ammonia and for amines 5 ppb by diethylamine. For the correct interpretation of the "electronic nose" results, we used the doctor’s diagnosis, their description of the condition and the severity of the lesion, which was defined by the results of microbiological research in the laboratory. At the first stage, it was established that to ensure the reliability of solution-making during sample ranking into groups, time from the moment of biomaterial sampling to the measurement should not exceed 3–5 min. At the appointment in the doctor’s office and as part of a preventative medical check-up, there were analyzed 83 bioassays according to the developed method. To elaborate a model of gynecological status assessment, there were chosen 30 conditionally healthy patients (scheduled patient care) and the ones with deviations from the conditional norm, suggesting antibacterial treatment with various inflammation histories (active form, remission, and exacerbation). To make a decision, we utilized the full amount of data, which is achieved while measuring volatile molecules above mucus during sorption (80 sec) and spontaneous desorption (120 sec). The methods and results of experimental processing of patients’ data obtained directly in a consulting room are described below. The most informative sensors were identified applying an unsupervised model for processing the output curves in bio-sample vapours. The reduction of the number of sensors in the array to one was justified. There was proved high accuracy of mucus sample ranking by presence/ absence of gynecologic disease within mere 60 s. Sensors’ data processing was carried out using machine-learning methods without a coach but with the pseudo markup. We proposed a self-learning model for bioassay separation into three classes based on the signals from the most sensitive sensor with a classification error of no more than 10%. We conducted distribution into diagnostic groups and verification of the correct classification of new samples according to the results of microbiological analysis for microflora and key cells, according to the culture test method for infectious agents of sexually transmitted diseases (Gardnerella, Candida. alb, ureaplasmosis Ureap. Parvum, Trichomonas vaginalis). For accurate confirmation of pathogens’ presence, the polymerase chain reaction method was used. The model allows us to predict processes of remission and the presence of previous illnesses in remission, not necessarily infectious (e.g., adhesion formation). Active inflammation processes of any nature are also predicted well. Characteristics of the model for prediction of the presence of sexually transmitted infections by the signals of one sensor are sensitivity – 64%, and specificity – 86%. The capacity of an analysis based on the developed method and the model constitutes 30–35 samples per shift. The minimal lifetime of the studied sensors with bio-hydroxyapatite phase is more than 12 months. In such a case, there was neither sensor calibration nor their training on test substances required. A comparative study was conducted to validate the accuracy of using the electronic nose system versus classic cultural and polymerase chain reaction methods.
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•The possibility of a quick on-site assessment of the condition of gynecological patients was positively assessed•A method has been developed for the determination of volatile compounds in a bioassay in the vapor diffusion mode•Algorithms are proposed for assessing the contribution of each matrix sensor to the analytical signal•A self-learning model for clustering biological mucus samples based on a single sensor signal in real time is proposed•The proposed uncontrolled model makes it possible to develop a portable device based on a single hydroxyapatite sensor.
Scientific relevance.
Deuterated analogues of test substances, when used as internal standards, enable analysts to determine traces of residual pesticides in a medicinal plant raw material by gas or ...liquid chromatography coupled with mass spectrometry. This prompts the search for an undemanding method for the synthesis of deuterated reference standards, with the ultimate goal of expanding the range of reference standards produced in Russia.
Aim
. The study aimed to synthesise deuterated reference standards (malathion-D
6
, chlorophos-D
6
, dichlorophos-D
6
, and their precursors) and determine their spectral characteristics using
1
Н,
2
Н,
13
С and
31
Р nuclear magnetic resonance (NMR) spectroscopy and high-resolution mass spectrometry.
Materials and methods.
The study involved methanol-D
4
, phosphorus pentasulfide, phosphorus trichloride, maleic acid diethyl ether, triethylamine, hydroquinone, and chloral hydrate. The authors recorded
1
H,
2
H,
13
C, and
31
P NMR spectra using a QONE AS400 NMR spectrometer operating at a temperature of 298 °K and respective frequencies of 399.83, 61.38, 100.55, and 161.85 MHz. Mass spectra were obtained using an analytical system comprising an Agilent Infinity 1260 liquid chromatograph equipped with an automatic sample injector and coupled with a Thermo Scientific Orbitrap Fusion Lumos high-resolution mass-selective tandem spectrometer operating in electrospray ionisation mode.
Results.
The authors used existing methods for the synthesis of organophosphate pesticides as a basis and developed synthesis routes to produce the deuterated analogues malathion-D
6
, chlorophos-D
6
, and dichlorophos-D
6
. The synthesised compounds were identified by NMR spectroscopy and high-resolution mass spectrometry.
Conclusions.
The synthesised compounds are highly pure and suitable for use as internal standards in the determination of organophosphate pesticides in medicinal plant raw materials. The synthesis methods developed by the authors can be used to produce reference standards in Russia.
Methods for phosphorylation of tyrosine and Tyr-Thr-Lys tripeptide with cyclohexylmethyl(deuteromethyl)phosphonochloridates have been developed. These products can be used as reference compounds in ...the analysis of blood plasma of patients presumably exposed to cyclohexylmethylphosphonofluoridate (cyclosarin) action. Conditions for the separation and purification of the synthesized intermediates by means of chromatography have been determined and optimized, allowing high-purity phosphorylated products at the final stage of the synthesis.
The study of labile humic substances of typical chernozems under different land uses in Kursk oblast with the help of thermal method attests to their complex composition with participation of ...aliphatic and cyclic structures heterogeneous in terms of their thermal stainability. According to the
Z
coefficient (the ratio between weight losses in the low-temperature (<400°С) and high-temperature region (>400°С)) equal to 1.10, aliphatic compounds predominate over cyclic benzenoid compounds in the composition of labile humic substances of virgin chernozems. Under the impact of permanent cultivation of winter wheat and corn, the mineralization of the aliphatic part of labile humic substances increases, and the Z coefficient decreases to 0.81–0.96. The most intense mineralization of aliphatic fragments of labile humic substances occurs under the impact of permanent black fallow, where the Z coefficient decreases to 0.76, and inert cyclic components clearly predominate in the composition of labile humic substances. In 23 years after the conversion of the permanent black fallow into the overgrown unmanaged fallow, the composition of the labile humic substances of the typical chernozem has not undergone significant changes, though a tendency for an increase in the role of aliphatic structures has been noted.
Sequencing the genomes of multiple, taxonomically diverse eukaryotes enables in-depth comparative-genomic analysis which is expected to help in reconstructing ancestral eukaryotic genomes and major ...events in eukaryotic evolution and in making functional predictions for currently uncharacterized conserved genes.
We examined functional and evolutionary patterns in the recently constructed set of 5,873 clusters of predicted orthologs (eukaryotic orthologous groups or KOGs) from seven eukaryotic genomes: Caenorhabditis elegans, Drosophila melanogaster, Homo sapiens, Arabidopsis thaliana, Saccharomyces cerevisiae, Schizosaccharomyces pombe and Encephalitozoon cuniculi. Conservation of KOGs through the phyletic range of eukaryotes strongly correlates with their functions and with the effect of gene knockout on the organism's viability. The approximately 40% of KOGs that are represented in six or seven species are enriched in proteins responsible for housekeeping functions, particularly translation and RNA processing. These conserved KOGs are often essential for survival and might approximate the minimal set of essential eukaryotic genes. The 131 single-member, pan-eukaryotic KOGs we identified were examined in detail. For around 20 that remained uncharacterized, functions were predicted by in-depth sequence analysis and examination of genomic context. Nearly all these proteins are subunits of known or predicted multiprotein complexes, in agreement with the balance hypothesis of evolution of gene copy number. Other KOGs show a variety of phyletic patterns, which points to major contributions of lineage-specific gene loss and the 'invention' of genes new to eukaryotic evolution. Examination of the sets of KOGs lost in individual lineages reveals co-elimination of functionally connected genes. Parsimonious scenarios of eukaryotic genome evolution and gene sets for ancestral eukaryotic forms were reconstructed. The gene set of the last common ancestor of the crown group consists of 3,413 KOGs and largely includes proteins involved in genome replication and expression, and central metabolism. Only 44% of the KOGs, mostly from the reconstructed gene set of the last common ancestor of the crown group, have detectable homologs in prokaryotes; the remainder apparently evolved via duplication with divergence and invention of new genes.
The KOG analysis reveals a conserved core of largely essential eukaryotic genes as well as major diversification and innovation associated with evolution of eukaryotic genomes. The results provide quantitative support for major trends of eukaryotic evolution noticed previously at the qualitative level and a basis for detailed reconstruction of evolution of eukaryotic genomes and biology of ancestral forms.
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The study of the elemental composition of labile humus substances passing into 0.1 M NaOH extract from typical chernozem under different cenoses indicated that, judging from the H : C ratio varying ...within 1.55–1.91, aliphatic structures predominate over cyclic components. Under the agrogenic impact, the processes demethylation, dehydrogenation, and oxidation of organic substances are developed in the chernozem. As a result, labile humic substances lose their aliphatic components and become enriched with oxidized nitrogen-containing cyclic structures. The intensity of this process increases in the series: permanent winter wheat > permanent corn > permanent bare fallow. At the same time, labile humic substances of the chernozem under permanent bare fallow are the least energy-intensive compounds as judged from the values of the heat of combustion found on the basis of elemental analysis data. Over the 23 years that have passed since the transfer of the permanent bare fallow to the unmanaged fallow overgrown by herbs, there have been no significant changes in the elemental composition of labile humus substances of typical chernozem, except for a tendency of their enrichment in newly formed aliphatic nitrogen-containing reduced and more energy-intensive compounds.
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