Based on our hypothesis for existing microbiota of wall-deficient variants (L-forms) in human blood, we created an innovative methodology, which allowed for the development of L-form populations from ...blood of all investigated people. In contrast to healthy controls, blood L-forms from autistic children and their mothers converted under appropriate conditions of cultivation into detectable opportunistic bacteria and fungi, а process demonstrated by light and transmission electron microscopy. It can be distinguished into two types of states - "eubiotic" blood microbiota in healthy individuals, and "dysbiotic" in autistic children and their mothers. Remarkably, the unifying finding for autistic children and their mothers was the presence in blood of wall-free variants from life-cycle of filamentous fungi. Increased specific IgG, IgM and IgA, together with typical mold growth were a decisive argument for proven presence of Aspergillus fumigatus in almost all of the autistic children. As it was demonstrated in our previous study, filterable L-forms can be transmitted by vertical pathway from mother to child before birth. Thus, it can be suggested that autistic children may be born already colonized with fungi, while a "silent aspergillosis" could contribute or even be a leading cause for neurodevelopmental disorders in the early childhood.
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•New PVDF and PVDF-HFP nanofibers decorated with ZnO nanoparticles and a model drug.•The nanofibrous materials were fabricated by one-pot electrospinning.•The obtained materials are superhybrophobic ...and possess antibacterial properties.
Superhydrophobic nanofibrous materials of poly(vinylidene fluoride) (PVDF) and poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) were prepared by one-pot electrospinning technique. The mats were decorated with ZnO nanoparticles with silanized surface and a model drug – 5-chloro-8-hydroxyquinolinol (5Cl8HQ). The obtained hybrid nanofibrous materials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), contact angle measurements, mechanical and microbiological tests. The results showed that the incorporation of ZnO nanoparticles into PVDF and PVDF-HFP nanofibers increased the hydrophobicity (contact angle 152°), improved the thermal stability and imparted to the nanofibrous materials anti-adhesive and antimicrobial properties. The mats containing the model drug possessed antibacterial activity against Escherichia coli and Staphylococcus aureus. The results suggested that the obtained hybrid mats could find potential biomedical applications requiring antibacterial and anti-biofouling properties.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Context. B-type supergiants represent an important phase in the evolution of massive stars. Reliable estimates of their stellar and wind parameters, however, are scarce, especially at mid and late ...spectral subtypes. Aims. We apply the NLTE atmosphere code FASTWIND to perform a spectroscopic study of a small sample of Galactic B-supergiants from B0 to B9. By means of the resulting data and incorporating additional datasets from alternative studies, we investigate the properties of OB-supergiants and compare our findings with theoretical predictions. Methods. Stellar and wind parameters of our sample stars are determined by line profile fitting, based on synthetic profiles, a Fourier technique to investigate the individual contributions of stellar rotation and "macro-turbulence" and an adequate approach to determine the Si abundances in parallel with micro- turbulent velocities. Results. Due to the combined effects of line- and wind-blanketing, the temperature scale of Galactic B-supergiants needs to be revised downward, by 10 to 20%, the latter value being appropriate for stronger winds. Compared to theoretical predictions, the wind properties of OB-supergiants indicate a number of discrepancies. In fair accordance with recent results, our sample indicates a gradual decrease in v_\infty over the bi-stability region, where the limits of this region are located at lower T_{\rm eff} than those predicted. Introducing a distance-independent quantity Q ' related to wind-strength, we show that this quantity is a well defined, monotonically increasing function of T_{\rm eff} outside this region. Inside and from hot to cool, dot M changes by a factor (in between 0.4 and 2.5) which is much smaller than the predicted factor of 5. Conclusions. The decrease in v_\infty over the bi-stability region is not over-compensated by an increase of dot M, as frequently argued, provided that wind-clumping properties on both sides of this region do not differ substantially.
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The 30 Doradus star-forming region in the Large Magellanic Cloud is a nearby analog of large star-formation events in the distant universe. We determined the recent formation history and the initial ...mass function (IMF) of massive stars in 30 Doradus on the basis of spectroscopic observations of 247 stars more massive than 15 solar masses (Formula: see text). The main episode of massive star formation began about 8 million years (My) ago, and the star-formation rate seems to have declined in the last 1 My. The IMF is densely sampled up to 200 Formula: see text and contains 32 ± 12% more stars above 30 Formula: see text than predicted by a standard Salpeter IMF. In the mass range of 15 to 200 Formula: see text, the IMF power-law exponent is Formula: see text, shallower than the Salpeter value of 2.35.
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BFBNIB, NMLJ, NUK, ODKLJ, PNG, SAZU, UL, UM, UPUK
Results of the Black Sea hydrophysical field reanalysis for the period of 1992-2012 are considered. The simulation was carried out using z-coordinate non-linear ocean model of the Marine ...Hydrophysical Institute. The hydrophysical fields were calculated with resolution of 4.8 km horizontally and by 38 vertical levels along the depth from the sea surface to the bottom. In contrast to a number of previous works, the focus now is on studying the variability of the Black Sea circulation below the main pycnocline (horizon of 300 m and deeper). Analysis of instantaneous and mean velocity fields is carried out, and main structural features are found in deep layers of the sea. It is shown that the most intensive dynamic structures are mainly the cyclonic mesoscale eddies moving from 33-38°E westward and passing through the abyssal central part of the sea. The problem of the existence of reverse (anticyclonic) deep currents opposite to the surface ones is also considered. It is shown that along the narrow north-eastern continental slope such currents exist occasionally. They are formed on the background of topography regional features mainly in summer and could be associated with the weakening of the overlying cyclonic Rim Current.
The VLT-FLAMES Tarantula Survey Schneider, F. R. N.; Ramírez-Agudelo, O. H.; Tramper, F. ...
Astronomy and astrophysics (Berlin),
10/2018, Volume:
618
Journal Article
Peer reviewed
Open access
The 30 Doradus (30 Dor) nebula in the Large Magellanic Cloud (LMC) is the brightest HII region in the Local Group and a prototype starburst similar to those found in high redshift galaxies. It is ...thus a stepping stone to understand the complex formation processes of stars in starburst regions across the Universe. Here, we have studied the formation history of massive stars in 30 Dor using masses and ages derived for 452 mainly OB stars from the spectroscopic VLT-FLAMES Tarantula Survey (VFTS). We find that stars of all ages and masses are scattered throughout 30 Dor. This is remarkable because it implies that massive stars either moved large distances or formed independently over the whole field of view in relative isolation. We find that both channels contribute to the 30 Dor massive star population. Massive star formation rapidly accelerated about 8 Myr ago, first forming stars in the field before giving birth to the stellar populations in NGC 2060 and NGC 2070. The R136 star cluster in NGC 2070 formed last and, since then, about 1 Myr ago, star formation seems to be diminished with some continuing in the surroundings of R136. Massive stars within a projected distance of 8 pc of R136 are not coeval but show an age range of up to 6 Myr. Our mass distributions are well populated up to 200 M⊙. The inferred IMF is shallower than a Salpeter-like IMF and appears to be the same across 30 Dor. By comparing our sample of stars to stellar models in the Hertzsprung–Russell diagram, we find evidence for missing physics in the models above log L/L⊙ = 6 that is likely connected to enhanced wind mass loss for stars approaching the Eddington limit. Our work highlights the key information about the formation, evolution and final fates of massive stars encapsulated in the stellar content of 30 Dor, and sets a new benchmark for theories of massive star formation in giant molecular clouds.
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The VLT-FLAMES Tarantula Survey Ramirez-Agudelo, O H; Sana, H; de Koter, A ...
Astronomy and astrophysics (Berlin),
4/2017, Volume:
600
Journal Article
Peer reviewed
Context. The Tarantula region in the Large Magellanic Cloud (LMC) contains the richest population of spatially resolved massive O-type stars known so far. This unmatched sample offers an opportunity ...to test models describing their main-sequence evolution and mass-loss properties. Aims. Using ground-based optical spectroscopy obtained in the framework of the VLT-FLAMES Tarantula Survey (VFTS), we aim to determine stellar, photospheric and wind properties of 72 presumably single O-type giants, bright giants and supergiants and to confront them with predictions of stellar evolution and of line-driven mass-loss theories. Methods. We apply an automated method for quantitative spectroscopic analysis of O stars combining the non-LTE stellar atmosphere model fastwind with the genetic fitting algorithm pikaia to determine the following stellar properties: effective temperature, surface gravity, mass-loss rate, helium abundance, and projected rotational velocity. The latter has been constrained without taking into account the contribution from macro-turbulent motions to the line broadening. Results. We present empirical effective temperature versus spectral subtype calibrations at LMC-metallicity for giants and supergiants. The calibration for giants shows a +1kK offset compared to similar Galactic calibrations; a shift of the same magnitude has been reported for dwarfs. The supergiant calibrations, though only based on a handful of stars, do not seem to indicate such an offset. The presence of a strong upturn at spectral type O3 and earlier can also not be confirmed by our data. In the spectroscopic and classical Hertzsprung-Russell diagrams, our sample O stars are found to occupy the region predicted to be the core hydrogen-burning phase by state-of-the-art models. For stars initially more massive than approximately 60M sub(middot in circle), the giant phase already appears relatively early on in the evolution; the supergiant phase develops later. Bright giants, however, are not systematically positioned between giants and supergiants at M sub(init)> or = 25M sub(middot in circle). At masses below 60M sub(middot in circle), the dwarf phase clearly precedes the giant and supergiant phases; however this behavior seems to break down at M sub(init)< or = 18M sub(middot in circle). Here, stars classified as late OIII and II stars occupy the region where O9.5-9.7 V stars are expected, but where few such late OV stars are actually seen. Though we can not exclude that these stars represent a physically distinct group, this behavior may reflect an intricacy in the luminosity classification at late O spectral subtype. Indeed, on the basis of a secondary classification criterion, the relative strength of Siiv to Hei absorption lines, these stars would have been assigned a luminosity class IV or V. Except for five stars, the helium abundance of our sample stars is in agreement with the initial LMC composition. This outcome is independent of their projected spin rates. The aforementioned five stars present moderate projected rotational velocities (i.e., nu sub(e) sini< 200kms super(-1)) and hence do not agree with current predictions of rotational mixing in main-sequence stars. They may potentially reveal other physics not included in the models such as binary-interaction effects. Adopting theoretical results for the wind velocity law, we find modified wind momenta for LMC stars that are ~0.3 dex higher than earlier results. For stars brighter than 10 super(5)L sub(middot in circle), that is, in the regime of strong stellar winds, the measured (unclumped) mass-loss rates could be considered to be in agreement with line-driven wind predictions if the clump volume filling factors were f sub(V)~ 1/8 to 1/6.
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Mechanisms of heat shock response in mammals Velichko, Artem K; Markova, Elena N; Petrova, Nadezhda V ...
Cellular and molecular life sciences : CMLS,
11/2013, Volume:
70, Issue:
22
Journal Article
Peer reviewed
Heat shock (HS) is one of the best-studied exogenous cellular stresses. The cellular response to HS utilizes ancient molecular networks that are based primarily on the action of stress-induced heat ...shock proteins and HS factors. However, in one way or another, all cellular compartments and metabolic processes are involved in such a response. In this review, we aimed to summarize the experimental data concerning all aspects of the HS response in mammalian cells, such as HS-induced structural and functional alterations of cell membranes, the cytoskeleton and cellular organelles; the associated pathways that result in different modes of cell death and cell cycle arrest; and the effects of HS on transcription, splicing, translation, DNA repair, and replication.
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EMUNI, NUK, SBMB, SBNM, UL, UM, UPUK
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•Micro- and nanofibrous mats from PLA and PEG were prepared by electrospinning.•PEG was incorporated using either physical blending, or chemical grafting.•PEG blending had a more ...pronounced plasticizing effect on PLA than chemical grafting.•Blended PLA/PEG mats were quasi-ductile, while PLA-g-poly(acrylPEG) mats were brittle.•Antibacterial fibers were obtained by incorporating 5-nitro-8-quinolinol as model drug.
Antibacterial micro- and nanofibrous materials based on polylactide (PLA) and polyethylene glycol (PEG) were prepared by electrospinning. PEG incorporation was achieved by its physical blending with or chemical grafting on PLA. The role of the incorporation method on the surface wettability, the thermal, the mechanical and the biological properties was studied in relation to mats applicability. Physical blending or chemical grafting did not significantly modify the wettability of the mats, but showed a plasticizing effect on PLA – more obvious in the case of the physical blend fibers in agreement with the higher PEG mobility. The mechanical properties of the mats were also influenced by the PEG incorporation method. Fibrous mats of physically blended PLA and PEG proved quasi-ductile, while brittle behavior was registered for the chemically grafted poly(l-lactide)-graft-polyethylene glycol methyl ether acrylate mats. 5-nitro-8-hydroxyquinoline (5N8Q) was loaded as a model antibacterial drug. The polyether incorporation method proved influencing the 5N8Q release profile with burst effect recorded for all PEG-containing mats. Additionally, all drug-loaded mats presented antibacterial activity against Staphylococcus aureus and Escherichia coli. Thus, the choice of polyether incorporation method is dependent on the targeted application of the antibacterial materials.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
•Exposure to the ionizing radiation in the Mars exploration mission doses significantly modulates the psycho-emotional status, but not cognition•The alteration of serotonin metabolism indicates the ...wide range of neuroadaptive rearrangements rather than the pathophysiologic process•We believe that the change in psycho-emotional status is indirectly responsible for the cognitive abilities shift
Human spaceflight launch is the big challenge that the humanity work on. The astronauts’ task performance vulnerability to ionizing radiations is one of the major factors limiting deep space missions. In this work, we study the effect of ionizing radiations (γ-quanta and 12C6+ in combination) on cognitive abilities and psycho-emotional status of Wistar rats. Irradiation led to the hyperlocomotion, increase of anxiety-like behavior, suppression of depressive-like behavior and enhancement of spatial learning. These data are consistent with the neurochemical/molecular analysis: enhanced monoaminergic innervation within the hypothalamus (HYP), inhibition of serotonin turnover in the prefrontal cortex and neurokenin 1 receptor overexpression in the amygdala (AMY). In addition, we observe decreased expression of certain biomolecules in the AMY (5-HT2c and 5-HT3) and in the HYP (5-HT2a, 5-HT4 and VMAT2) that can be explained as neuroadaptive changes. Thus, the ionizing radiation exposure significantly modulates the psycho-emotional status. With that, for the first time we received data that radiation effects in the doses and composition of interplanetary space (in terrestrial modeling) could be relatively safe for cognitive functions.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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