3,782 research outputs found

    Detection of Giant Radio Pulses from the Pulsar PSR B0656+14

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    Giant pulses (GPs) have been detected from the pulsar PSR B0656+14. A pulse that is more intense than the average pulse by a factor of 120 is encountered approximately once in 3000 observed periods of the pulsar. The peak flux density of the strongest pulse, 120 Jy, is a factor of 630 higher than that of the average pulse. The GP energy exceeds the energy of the average pulse by up to a factor of 110, which is comparable to that for other known pulsars with GPs, including the Crab pulsar and the millisecond pulsar PSR B1937+21. The giant pulses are a factor of 6 narrower than the average pulse and are clustered at the head of the average pulse. PSR B0656+14 along with PSR B0031-07, PSR B1112+50, and PSR J1752+2359 belong to a group of pulsars that differ from previously known ones in which GPs have been detected without any extremely strong magnetic field on the light cylinder.Comment: 10 pages, 3 figures, 1 table; originally published in Russian in Pis'ma Astron. Zh., 2006, v.32, 650; translated by George Rudnitskii; the English version will be appear in Astronomy Letter

    Evaluation of various RNA-seq approaches for identification of gene outrons in the flatworm Opisthorchis felineus

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    The parasitic flatworm Opisthorchis felineus is one of the causative agents of opisthorchiasis in humans. Recently, we assembled the O. felineus genome, but the correct genome annotation by means of standard methods was hampered by the presence of spliced leader trans-splicing (SLTS). As a result of SLTS, the original 5’-end (outron) of the transcripts is replaced by a short spliced leader sequence donated from a specialized SL RNA. SLTS is involved in the RNA processing of more than half of O. felineus genes, making it hard to determine the structure of outrons and bona fide transcription start sites of the corresponding genes and operons, being based solely on mRNA-seq data. In the current study, we tested various experimental approaches for identifying the sequences of outrons in O. felineus using massive parallel sequencing. Two of them were developed by us for targeted sequencing of already processed branched outrons. One was based on sequence-specific reverse transcription from the SL intron toward the 5’-end of the Y-branched outron. The other used outron hybridization with an immobilized single-stranded DNA probe complementary to the SL intron. Additionally, two approaches to the sequencing of rRNA-depleted total RNA were used, allowing the identification of a wider range of transcripts compared to mRNAseq. One is based on the enzymatic elimination of overrepresented cDNAs, the other utilizes exonucleolytic degradation of uncapped RNA by Terminator enzyme. By using the outron-targeting methods, we were not able to obtain the enrichment of RNA preparations by processed outrons, which is most likely indicative of a rapid turnover of these trans-splicing intermediate products. Of the two rRNA depletion methods, a method based on the enzymatic normalization of cDNA (Zymo-Seq RiboFree) showed high efficiency. Compared to mRNA-seq, it provides an approximately twofold increase in the fraction of reads originating from outrons and introns. The results suggest that unprocessed nascent transcripts are the main source of outron sequences in the RNA pool of O. felineus

    Analysis of the placental tissue transcriptome of normal and preeclampsia complicated pregnancies

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    Preeclampsia is one of the most severe gestational complications which is one of the leading causes of maternal and perinatal morbidity and mortality. A growth in the incidence of severe and combined forms of the pathology has been observed in recent years. According to modern concepts, inadequate cytotrophoblast invasion into the spiral arteries of the uterus and development of the ischemia-reperfusion syndrome in the placental tissue play the leading role in the development of preeclampsia, which is characterized by multipleorgan failure. In this regard, our work was aimed at studying the patterns of placental tissue transcriptome that are specific to females with PE and with physiological pregnancy, as well as identifying the potential promising biomarkers and molecular mechanisms of this pathology. We have identified 63 genes whose expression proved to differ significantly in the placental tissue of females with PE and with physiological pregnancy. A cluster of differentially expressed genes (DEG) whose expression level is increased in patients with preeclampsia includes not only the known candidate genes that have been identified in many other genome-wide studies (e.g., LEP, BHLHB2, SIGLEC6, RDH13, BCL6), but also new genes (ANKRD37, SYDE1, CYBA, ITGB2, etc.), which can be considered as new biological markers of preeclampsia and are of further interest. The results of a functional annotation of DEG show that the development of preeclampsia may be related to a stress response, immune processes, the regulation of cell-cell interactions, intracellular signaling cascades, etc. In addition, the features of the differential gene expression depending on preeclampsia severity were revealed. We have found evidence of the important role of the molecular mechanisms responsible for the failure of immunological tolerance and initiation of the pro-inflammatory cascade in the development of severe preeclampsia. The results obtained elaborate the concept of the pathophysiology of preeclampsia and contain the information necessary to work out measures for targeted therapy of this disease.

    Changes in the transcriptome of the prefrontal cortex of OXYS rats as the signs of Alzheimer’s disease development

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    Alzheimer’s disease (AD) is the most prevalent neuro­degenerative disease. It produces atrophic changes in the brain, which cause dementia. The incidence of AD is increasing with increasing life expectancy and gradual aging of the population in developed countries. There are no effective prophylactic inter­ventions because of insufficient understanding of the AD pathogenesis and the absence of adequate experimental models. Recently, we showed that senescence-accelerated OXYS rats represent a promis­ing model of AD; in these rats, accelerated aging of the brain is accompanied by the typical signs of AD: degenerative alterations and death of neurons, a de­crease in synaptic density, mitochondrial dysfunction, hyperphosphorylation of the tau protein, an increased level of amyloid β (Aβ1–42), and the formation of amyloid plaques. To elucidate how these signs develop, we used a nextgeneration RNA sequencing technique (RNA-Seq) to study the prefron­tal-cortex transcriptome of OXYS rats during the manifestation of AD signs (at an age of 5 months) and during their active progres­sion (at an age of 18 months), using age-matched Wistar rats (parental strain) as controls. At the age of 5 months, there were significant differences between OXYS and Wistar rats (p < 0.01) in the mRNA expression of more than 900 genes (> 2000 genes at the age of 18 months) in the prefrontal cortex. Most of these genes were related to neuronal plasticity, protein phosphorylation, Са2+ homeostasis, hypoxia, immune processes, and apoptosis. Between the ages of 5 and 18 months, there were changes in the expression of 499 genes in Wistar rats and changes in the expres­sion of 5500 genes in OXYS rats. Only 333 genes were common between these sets. This finding points to differences in the mechanisms and rates of age-related changes in the brain between normal aging and the period of development of AD-specific neuro­degene­rative processes

    Excitations in the Halo Nucleus He-6 Following The Li-7(gamma,p)He-6 Reaction

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    A broad excited state was observed in 6-He with energy E_x = 5 +/- 1 MeV and width Gamma = 3 +/- 1 MeV, following the reaction Li-7(gamma,p)He-6. The state is consistent with a number of broad resonances predicted by recent cluster model calculations. The well-established reaction mechanism, combined with a simple and transparent analysis procedure confers considerable validity to this observation.Comment: 3 pages of LaTeX, 3 figures in PostScript, approved for publication in Phys. Rev. C, August, 200

    Three-body correlations in direct reactions: Example of 6^{6}Be populated in (p,n)(p,n) reaction

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    The 6^{6}Be continuum states were populated in the charge-exchange reaction 1^1H(6^{6}Li,6^{6}Be)nn collecting very high statistics data (5×106\sim 5 \times 10^6 events) on the three-body α\alpha+pp+pp correlations. The 6^{6}Be excitation energy region below 3\sim 3 MeV is considered, where the data are dominated by contributions from the 0+0^+ and 2+2^+ states. It is demonstrated how the high-statistics few-body correlation data can be used to extract detailed information on the reaction mechanism. Such a derivation is based on the fact that highly spin-aligned states are typically populated in the direct reactions.Comment: submitted to Physical Review

    CFD Modelling of the Condensation, Evaporation, Coagulation and Crystallization Processes in the Cooling Tower Emissions

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    The aim of the paper is to develop the CFD model for the environmental impact assessment of the cooling tower. The methods applied for this problem are the single-phase turbulent multispecies flow modelling with the DPM Lagrangian particle tracking. The simulations have been carried out in the steady state SIMPLE solver using the ANSYS Fluent software. User Defined Functions have been defined to enhance the accuracy and versatility of the modelling approach in terms of turbulence, fog formation, evaporation, coagulation and crystallization modelling. The Chalk Point cooling tower experiment, laboratory tests with freezing droplets and analytical correlations are used to verify the customized parts of the new CFD model. The arbitrary small-town geometry is used to demonstrate the simulation capabilities of the fog and drift deposition as well as the temperature and relative humidity values near ground and buildings. The results indicate that the new CFD model is able to predict the cooling tower plume parameters, icing and salt contamination risks as well as drift deposition. © 2021 Institute of Physics Publishing. All rights reserved

    Genomics and proteomics of the liver fluke <em>Opisthorchis felineus</em>

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    The causative agent of opisthorchiasis, the liver fluke Opisthorchis felineus (Rivolta, 1884) is one of the helminths of humans and animals in Russia. Together with closely related species of trematodes O. viverrini (Poirier, 1886) and Clonorchis sinensis (Loos, 1907), O. felineus is a part of a triad of epidemiologically important trematodes in the family Opisthorchiidae. Adult O. felineus worms infest the hepatobiliary system of warm-blooded animals and might provoke the development of severe pathologies, including malignancy of bile duct epithelium. The high medical importance of O. felineus attracts the attention of researchers. This review briefly summarizes the data about O. felineus genomics and proteomics. The review provides a comparative analysis of the number of genes and sizes of nuclear genomes of a number of flatworms, the distribution of intron lengths, as well as results of synteny between the O. felineus, O. viverrini and C. sinensis genomes. Special attention is paid to a particular form of RNA processing known as trans-splicing, widely presented in the opisthorchiid genomes. We also provide the results of a comparative analysis of the xenobiotic metabolizing system between parasitic and free-living flatworms. Moreover, data on parasitic granulins, which are potential promoters of cholangiocyte neoplasia, are also presented. Data on the O. felineus genomics and proteomics provide first insights into the structural and functional organization of the genome of this parasitic flatworm with a complex life cycle as well as provide a significant contribution to our understanding of “host-parasite” interaction and evolution of this group of parasitic flatworms

    Synthesis and Cytotoxic Effect of 1-Aryl-Substituted-6-Imino-2,7-Dioxabicyclo[3.2.1]Octane-4,4,5-Tricarbonitriles

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    The work was carried out within the framework of scholarship SP-127.2016.4 from the President of the Russian Federation for young scientists and graduate students
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