A repeating fast radio burst source in a globular cluster.

Fast radio bursts (FRBs) are flashes of unknown physical origin1. The majority of FRBs have been seen only once, although some are known to generate multiple flashes2,3. Many models invoke magnetically powered neutron stars (magnetars) as the source of the emission4,5. Recently, the discovery6 of another repeater (FRB 20200120E) was announced, in the direction of the nearby galaxy M81, with four potential counterparts at other wavelengths6. Here we report observations that localized the FRB to a globular cluster associated with M81, where it is 2 parsecs away from the optical centre of the cluster. Globular clusters host old stellar populations, challenging FRB models that invoke young magnetars formed in a core-collapse supernova. We propose instead that FRB 20200120E originates from a highly magnetized neutron star formed either through the accretion-induced collapse of a white dwarf, or the merger of compact stars in a binary system7. Compact binaries are efficiently formed inside globular clusters, so a model invoking them could also be responsible for the observed bursts.

[Autologous bone implant for reconstructive surgery after decompressive craniectomy in children]. / Sposob khraneniya i pogotovki kostnogo autotransplantata dlya zakrytiya defektov svoda cherepa u detei posle dekompressivnoi trepanatsii cherepa.

The concept of post-traumatic skull defect closure is based on restoration of anatomical relationships for the maximum possible recovery of brain function, i.e. it is considered as a stage of surgical rehabilitation. The choice of implants in pediatric patients is limited. In this regard, the «gold standard¼ is still autologous bone implant. MATERIAL AND METHODS: We propose a method for storage and sterilization of autologous bone implant. The last one implies keeping at a temperature of -80 ˚C with sterilization in a vacuum chamber filled with hydrogen peroxide vapors of biocidal plasma medium. Sterilization is provided by 45-minute cycle immediately before surgery. We report skull defect closure using autologous bone implants in 79 patients. Evaluation of effectiveness of storage and sterilization of autologous bone implant included analysis of mechanical properties of bone after sterilization, intra-operative microbiological monitoring, incidence of infections in early postoperative period, follow-up with assessment of resorption. RESULTS: Early infectious complications occurred in 2 patients (2.5%). Complete resorption with redo surgery occurred in 6 (10.1%) cases. Sterilization in low-temperature plasma of hydrogen peroxide changes mechanical properties of the bone, increases durability under compressive stresses and decreases durability under tensile conditions. This does not affect functional tasks of autologous bone. The proposed method of storage and sterilization is accompanied by low risk of infections and resorption. Storage of autologous bone implant at a temperature of -80 ˚C with subsequent sterilization in low-temperature plasma of hydrogen peroxide can be considered as a safe and effective method for skull defect closure in children after decompressive surgery.

Speckle patterning of a pumping laser light as a limiting factor for stimulated fluorescence emission in dense random media.

The features of fluorescence emission in a dye-doped dense multiple scattered medium under pulsed laser pumping are considered in terms of confined excitation in small zones associated with laser speckles occurring in a pumped medium. The results of numerical modeling of the fluorescence emission kinetics are compared to the experimental data obtained using the rhodamine 6G-doped layers of the densely packed TiO2 (anatase) particles pumped at 532 nm by 10 ns laser pulses. The intensity of pump radiation during the action of laser pulses was varied from 1·105 W/cm2 to 5·107 W/cm2. In the recovery of the ratios of stimulated to a spontaneous emission, the spectra of the stimulated component were fitted using the spectral function derived by R. Dicke. In the framework of the considered concept, saturation of the ratio of the stimulated to a spontaneous emission and linear growth of an integrated fluorescence output with a practically unchangeable half-width of the emission spectra at high pump intensities are interpreted.

Regional variability of integral intensity of bioluminescence of hydrobionts in the waters of the Black Sea in the summer period under the influence of hydrophysical processes.

Characterization of hydrobionts concentrations in coastal and deep-water areas of the Black Sea during the summer was carried out to analyse features related to the vertical distribution of bioluminescence intensity in the phytoplankton community. The thermohaline structure of the water and regional characteristics of eddy formations determined from satellite measurements of sea level anomalies were taken into account. Integral intensity of bioluminescence of hydrobionts (IIBH) was used to comparatively assess total biomass variability and the numbers of hydrobionts in the considered regions. The highest IIBH, averaging 37 830 pW·cm-2 ·L-1 , was observed at stations located on the south-western shelf of the Crimea; high levels of bioluminescence intensity of hydrobionts in this layer were located at depths of 15-23 m. For stations located in the Kerch pre-strait area, most of which were in the divergence zone, the average IIBH was quite high (30 530 pW·cm-2 ·l-1 ), second only to the value recorded for the shallow south-western shelf.

Relaxation times measurement in single and multiply excited xenon clusters.

Direct measurement of the rates of nonradiative relaxation processes in electronically excited xenon clusters was carried out. The clusters were created in a pulsed supersonic beam and two-photon excited by femtosecond laser pulses with a wavelength of 263 nm. The measurements were performed using the pump-probe method and electron spectroscopy. It is shown that relaxation of light clusters XeN (N < 15) predominantly occurs by desorption of excited xenon atoms with a characteristic time constant of 3 ps. Heavier electronically excited clusters (N > 10) vibrationally relax to the lowest electronically excited state at a rate of about 0.075 eV/ps. Multiply excited clusters are deactivated via energy exchange between excited centers with the ionization of one of them. The production of electrons in this process occurs with a delay of ∼4 ps from the pump pulse, and the process is completed in 10 ps.

[Parameters of clobal longitudinal myocardial deformation and coronary bloodflow in patients with primary hypothyroidism].

AIMS: Assessment of global longitudinal strain of left ventricle and coronary bloodflow in patients with primary subclinical hypothyroidism. MATERIALS AND METHODS: The study involved 23 women with primary subclinical hypothyroidism of age from 55 to 75 years. Physical examination, transthoracic EchoCG, coronary bloodflow assessment and global LV longitudinal strain by speckle tracking method were performed to all patients. The data obtained were compared to the results of 20 women without any thyroid diseases comparable to the main group by age and concomitant diseases. RESULTS: Patients with primary subclinical hypothyroidism have signs of diastolic dysfunction significantly more frequently than in control group, and increased values of posterior left ventricle wall and interventricular septum thickness. Global longitudinal strain of left ventricle in patients with hypothyroidism was lower than in control group and patients with hypothyroidism had higher FVI values in perforant coronary arteries. CONCLUSION: Patients with subclinical hypothyroidism demonstrated decrease of global longitudinal strain and increase of volume bloddflow rate in performant coronary arteries.

Observation of Oscillatory Radial Electric Field Relaxation in a Helical Plasma.

Measurements of the relaxation of a zonal electrostatic potential perturbation in a nonaxisymmetric magnetically confined plasma are presented. A sudden perturbation of the plasma equilibrium is induced by the injection of a cryogenic hydrogen pellet in the TJ-II stellarator, which is observed to be followed by a damped oscillation in the electrostatic potential. The waveform of the relaxation is consistent with theoretical calculations of zonal potential relaxation in a nonaxisymmetric magnetic geometry. The turbulent transport properties of a magnetic confinement configuration are expected to depend on the features of the collisionless damping of zonal flows, of which the present Letter is the first direct observation.

Comparison of exciplex generation under optical and X-ray excitation.

Exciplex generation under optical and X-ray excitation in identical conditions is experimentally compared using a specially chosen model donor-acceptor system, anthracene (electron acceptor) and N,N-dimethylaniline (electron donor) in non-polar solution, and the results are analyzed and interpreted based on analytically calculated luminescence quantum yields. Calculations are performed on the basis of kinetic equations for multistage schemes of bulk exciplex production reaction under optical excitation and combination of bulk and geminate reactions of radical ion pairs under X-ray excitation. These results explain the earlier experimentally found difference in the ratio of the quantum yields of exciplexes and excited electron acceptors (exciplex generation efficiency) and the corresponding change in the exciplex generation efficiency under X-irradiation as compared to the reaction under optical excitation.

Postural Performance at Different Breathing Strategies in Patients with Limitation of Mobility.

We investigated the effect of different breathing strategies on postural performance in the patients with joint mobility limitations. The amplitude and velocity of thecenter-of-pressure movements in the frontal.and sagittal planes were measured by the force platform in48 healthy volunteers. The stability of vertical posture was estimated during normal breathing, inspiratory and expiratory breath holding and hyperventilation with immobilization of the neck, trunk, hip and knee joints, and without immobilization. In general, the restriction of mobility caused a reduction in the postural stability in the sagittal plane, while the frontalbody swayamplitude decreased. These results suggest that body immobilization reduces the ability to compensate the effect of respiration on the stability of vertical posture in the sagittal plane and, on the contrary, facilitatesthe balance in the frontal plane.

Infrascanner in the diagnosis of intracranial lesions in children with traumatic brain injuries.

BACKGROUND: The number of traumatic injuries among children is increasing. However, so-called mild TBI might result in unfavourable outcomes. Early diagnosis of intracranial haematomas prior to development of serious complications may be a decisive factor for a favourable outcome. InfraScan company developed and brought to the market the Infrascanner model 1000, which is a portable detector of blood collections that operates in the near infrared (NIR) band. OBJECTIVE: To estimate the efficiency of the Infrascanner model 1000 for detection of intracranial haematomas among children with mild TBI. MATERIALS AND METHODS: Ninety-five patients with mild TBI were examined. An indication for cerebral CT after mild TBI was the presence of risk factors of intracranial lesions. The Infrascanner was used by a neurosurgeon during primary examination. CT was performed in 43 patients (45%), while 52 patients (55%) with a low risk of intracranial lesions were under observation. RESULTS: The results of examination of patients using CT and infrared scanning coincided in 39 cases and intracranial haematomas were detected in eight patients. False-positive results were obtained in three cases. The sensitivity of the procedure used in this group of patients with a medium and high risk of development of intracranial haemorrhages was 1.00 (0.66; 1.00). The specificity was 0.91 (0.81; 1.00)--the proportions and a 95% CI. The false-positive risk is 0.27 (0.00; 0.58). During infrared scanning in patients with low risk of intracranial lesions, false-positive results were obtained in four cases and false-negative results were absent. CONCLUSION: Infra-scanning might be viewed as a screening technique for intracranial haemorrhages in ambulances and outpatient trauma centres in order to decide on hospitalization, CT scanning and referral to a neurosurgeon. Infra-scanning combined with evaluation of risk factors of intracranial damage might reduce the number of unnecessary radiological examinations.

Relaxation channels of multi-photon excited xenon clusters.

The relaxation processes of the xenon clusters subjected to multi-photon excitation by laser radiation with quantum energies significantly lower than the thresholds of excitation of atoms and ionization of clusters were studied. Results obtained by means of the photoelectron spectroscopy method showed that desorption processes of excited atoms play a significant role in the decay of two-photon excited xenon clusters. A number of excited states of xenon atoms formed during this process were discovered and identified.

[SKEWED X-CHROMOSOME INACTIVATION IN HUMAN MISCARRIAGES].

Sex ratio in first trimester of pregnancy is skewed due to preferential elimination of female embryos. It could be resulted from aberrant X-chromosome inactivation. X-chromosome inactivation was analyzed in extraembryonic tissues of miscarriages and induced abortions with 46, XX karyotype. In chorion cytotrophoblast of both miscarriages and induced abortions observed either random or skewed X-chromosome inactivation. In extraembryonic mesoderm of the control group, random inactivation was observed, whereas 15% of miscarriages had skewed X-chromosome inactivation. The highest frequency of skewed inactivation of one of the parental homologues was observed in the groups of blighted ovum pregnancy and embryos from women with recurrent pregnancy loss. It was suggested that in these cases compartmentalization of cells in the blastocyst probably leads to predominance of cell with mutant active X-chromosome among the cells of inner cell mass carrying the aberrations that are incompatible with normal embryonic development.

[Sleep and fine motor skills: the influence of sex and level of physical activity]. / Son i tonkaya motorika: vliyanie pola i urovnya dvigatel'noi aktivnosti.

OBJECTIVE: To examine the influence of sleep quality on psychophysiological testing results and autonomic state in university students of both sexes with different habitual physical activity level. MATERIAL AND METHODS: One hundred and twenty-four 6th year medical students (88 women and 36 men) and 80 sport science students (42 women and 38 men) underwent a comprehensive psychophysiological study, including 7 tests: simple motor reaction, choice reaction, reaction under conditions of interference, reaction to a moving object, critical fusion frequency, as well as static and dynamic (by profile) dexterity tests. Autonomic status was assessed using heart rate variability, sleep quality and alertness were assessed based on self-report, and in athletes, using the Pittsburgh Sleep Quality Questionnaire (PSQI). RESULTS: In the male athletes' group with morning chronotype the sleep quality was better than in medical students. Only female medical students demonstrated a deterioration in praxis with an increase in the severity of evening features in the chronotype and a decrease in self-assessment of sleep quality. Increased sleepiness in the first half hour after awakening significantly reduced the quality of performance of psychometric tests in all subjects. The most informative was critical fusion frequency, which was lower in girls with «poor¼ sleep, as well as the reaction to a moving object. In addition, sympathetic drive was increased in female medical students with poor self-rated sleep quality. CONCLUSION: A decrease in the quality of sleep in students causes fine motor impairment, mediated by sex, the level of habitual physical activity and circadian chronotype.

New supramolecular Au(I)-Cu(I) complex as potential luminescent label for proteins.

A novel supramolecular [Au6Cu2(C2C6H4-4-COONC4H4O2)6(Ph2PC6H4PPh2)3](PF6)2 complex functionalized with a succinimide ester alkynyl substituent has been synthesized and characterized using X-ray crystallography, mass spectrometry, and NMR spectroscopy. Like the other complexes of this class, it demonstrates bright emission in acetone and dichloromethane solutions with the excited state lifetime in a microsecond domain. This complex readily reacts with a surface amine group of proteins/enzymes (human serum albumin (HSA), rabbit anti-HSA antibodies, soybean trypsin inhibitor, and α-chymotrypsin) to give covalent conjugates, which contain up to five molecules of the luminescent label bound to the biomolecule. The conjugates keep a high level of the phosphorescent label emission, but in contrast to the parent complex molecule, display excellent solubility and high stability in physiological media. Investigation of the biological activity of the conjugates also showed that the specific structure of the biomolecules remained nearly unchanged upon bonding with the label, which is indicative of a very prospective of the conjugates application in biomolecular detection.

Mass-resolved two-photon and photoelectron spectra of ArXe in the region of Xe* 7p, 6p', 6d.

The two photon resonant, three photon ionization spectra of ArXe were recorded in the spectral region of 88,500-90,100 cm(-1). Seven new molecular band progressions dissociating to ArXe* → Ar(1)S0 + Xe* 7p[1/2]0, Xe* 7p[3/2]2, Xe* 6p'[3/2]2, Xe* 6p'[1/2]1, Xe* 6p'[1/2]0 have been selected and analyzed. The molecular constants for the excited states of ArXe* of these vibrational progressions were determined in the approximation of the anharmonic oscillator, the Morse potential and the Franck-Condon principle. The photoelectron spectra were recorded by several excited electronic-vibrational transitions of ArXe, the dissociation channels of the excited molecules were determined and extra information about the electron structure of the excited molecular states was obtained.

Time-of-flight mass spectrometer for diagnostics of continuous plasma flow.

This paper describes a version of the time-of-flight mass spectrometer based on a modified two-field acceleration approach of Wiley and McLaren. The aim of the device is a diagnostic of continuous plasma flow. The acceleration scheme idea, the construction of the spectrometer, and results of testing in plasma flow of Gd and CeO2 generated by vacuum arc discharge are described. The instrument function of the spectrometer was measured, and its mass resolution was evaluated as ∼20. With the use of the instrument function, how to interpret the registered signal in the case of intersection of mass peaks was suggested. The presented device has a simple construction and relatively low values of applied acceleration voltages, so it has fewer requirements in manufacturability and cost.

[Psychosocial factors influencing the dynamics and sleep quality in medical students]. / Psikhosotsial'nye faktory, vliyayushchie na dinamiku i kachestvo sna studentov meditsinskogo vuza.

OBJECTIVE: To analyze the dynamics and sleep quality in medical students during 2005-2009 years and evaluate possible factors influencing this process. MATERIAL AND METHODS: The study included 2788 medical 1st, 4th and 6th year students (1919 girls, 869 young men). All participants underwent comprehensive psychophysiological testing. Self-reported questionnaire containing 45 questions about sleep quality, sleep hygiene, chronotype, behaviour was administered. Five hundred and seventeen girls and 260 young men were studied twice. RESULTS AND CONCLUSION: During 14 years, a negative sleep quality trend was observed in university students of all groups. The poor sleep group in 2019 consisted of 12.0-13.4% of girls and 8.2-18.4% of young men. About half of students have rated their own sleep as good (48.9-58.3% of girls and 52.2-55.4% of young men). From the first up to last semester of the study sleep quality is getting worse. The prospective analysis revealed the greater negative prognostic impact of self-reported poor sleep on academic performance in girls compared with young men. In the 4th year of the study, there were many poor-sleepers of both genders required more years of study for successful academic achievement. Students reported poor sleep were more activated and performed psychometrical tasks faster. Sleep quality, especially in girls, was significantly correlated with 19 psychosocial factors. The reliable marker of poor sleep may be feeling of lack of time both in girls (r= -0.32, p<0.01; r= -0.29, p<0.01; r= -0.22, p<0.05, respectively) and young men (r= -0.21, p<0.05; r= -0.34, p<0.01; r= -0.27, p<0.05, respectively) in their 1st, 4th and 6th study year, and the consequence was the slower transition to active functioning in the morning and lower health self-evaluation.

Episodes of Rapid Recovery of the Functional Activity of the ras85D Gene in the Evolutionary History of Phylogenetically Distant Drosophila Species.

As assemblies of genomes of new species with varying degrees of relationship appear, it becomes obvious that structural rearrangements of the genome, such as inversions, translocations, and transposon movements, are an essential and often the main source of evolutionary variation. In this regard, the following questions arise. How conserved are the regulatory regions of genes? Do they have a common evolutionary origin? And how and at what rate is the functional activity of genes restored during structural changes in the promoter region? In this article, we analyze the evolutionary history of the formation of the regulatory region of the ras85D gene in different lineages of the genus Drosophila, as well as the participation of mobile elements in structural rearrangements and in the replacement of specific areas of the promoter region with those of independent evolutionary origin. In the process, we substantiate hypotheses about the selection of promoter elements from a number of frequently repeated motifs with different degrees of degeneracy in the ancestral sequence, as well as about the restoration of the minimum required set of regulatory sequences using a conversion mechanism or similar.

A synchrotron computed tomography dataset for validation of longitudinal tensile failure models based on fibre break and cluster development.

We performed in-situ tensile tests on two carbon fibre/epoxy composites with continuous scanning using synchrotron computed tomography (CT). Both composites were cross-ply laminates, and two specimens were tested for each composite. The voxel size was sufficiently small to recognize individual fibres and fibre breaks. For each test, 16-19 volumes were reconstructed, cropped down to the 0° plies and analysed to track fibre break and cluster development. This dataset provides the last CT volume before failure for each of the four specimens as well as the individual fibre break locations in all reconstructed volumes. These data are then plotted against predictions from six state-of-the-art strength models. The target is that these data become a benchmark for the development of new models, inspiring researchers to set up refined experiments and develop improved models.