127 research outputs found
Cool spots on the surface of the active giant PZ Mon
Based on the multiband (BVRIJHKL) photometric observations of the active red
giant PZ Mon performed for the first time in the winter season of 2017-2018, we
have determined the main characteristics of the spotted stellar surface in a
parametric three-spot model. The unspotted surface temperature is Teff=4730 K,
the temperature of the cool spots is Tspot=3500 K, their relative area is about
41%, and the temperature of the warm spots is Twarm=4500 K with a maximum
relative area up to 20%. The distribution of spots over the stellar surface has
been modeled. The warm spots have been found to be distributed at various
longitudes in the hemisphere on the side of the secondary component and are
most likely a result of its influence.Comment: 5 pages, 7 figure
Functional Characterization of Lamina X Neurons in ex-Vivo Spinal Cord Preparation
Functional properties of lamina X neurons in the spinal cord remain unknown despite
the established role of this area for somatosensory integration, visceral nociception,
autonomic regulation and motoneuron output modulation. Investigations of neuronal
functioning in the lamina X have been hampered by technical challenges. Here we
introduce an ex-vivo spinal cord preparation with both dorsal and ventral roots still
attached for functional studies of the lamina X neurons and their connectivity using an
oblique LED illumination for resolved visualization of lamina X neurons in a thick tissue.
With the elaborated approach, we demonstrate electrophysiological characteristics
of lamina X neurons by their membrane properties, firing pattern discharge and
fiber innervation (either afferent or efferent). The tissue preparation has been also
probed using Ca2+ imaging with fluorescent Ca2+ dyes (membrane-impermeable or
-permeable) to demonstrate the depolarization-induced changes in intracellular calcium
concentration in lamina X neurons. Finally, we performed visualization of subpopulations
of lamina X neurons stained by retrograde labeling with aminostilbamidine dye to
identify sympathetic preganglionic and projection neurons in the lamina X. Thus, the
elaborated approach provides a reliable tool for investigation of functional properties
and connectivity in specific neuronal subpopulations, boosting research of lamina X of
the spinal cord
Wildfire smoke in the Siberian Arctic in summer: source characterization and plume evolution from airborne measurements
We present airborne measurements of carbon dioxide (CO<sub>2</sub>), carbon monoxide (CO), ozone (O<sub>3</sub>), equivalent black carbon (EBC) and ultra fine particles over North-Eastern Siberia in July 2008 performed during the YAK-AEROSIB/POLARCAT experiment. During a "golden day" (11 July 2008) a number of biomass burning plumes were encountered with CO mixing ratio enhancements of up to 500 ppb relative to a background of 90 ppb. Number concentrations of aerosols in the size range 3.5–200 nm peaked at 4000 cm<sup>&minus;3</sup> and the EBC content reached 1.4 &mu;g m<sup>&minus;3</sup>. These high concentrations were caused by forest fires in the vicinity of the landing airport in Yakutsk where measurements in fresh smoke could be made during the descent. We estimate a combustion efficiency of 90 &plusmn; 3% based on CO and CO<sub>2</sub> measurements and a CO emission factor of 65.5 &plusmn; 10.8 g CO per kilogram of dry matter burned. This suggests a potential increase in the average northern hemispheric CO mixing ratio of 3.0–7.2 ppb per million hectares of Siberian forest burned. For BC, we estimate an emission factor of 0.52 &plusmn; 0.07 g BC kg<sup>&minus;1</sup>, comparable to values reported in the literature. The emission ratio of ultra-fine particles (3.5–200 nm) was 26 cm<sup>&minus;3</sup> (ppb CO)<sup>&minus;1</sup>, consistent with other airborne studies. <br><br> The transport of identified biomass burning plumes was investigated using the FLEXPART Lagrangian model. Based on sampling of wildfire plumes from the same source but with different atmospheric ages derived from FLEXPART, we estimate that the e-folding lifetimes of EBC and ultra fine particles (between 3.5 and 200 nm in size) against removal and growth processes are 5.1 and 5.5 days respectively, supporting lifetime estimates used in various modelling studies
Distinct mechanisms of signal processing by lamina I spino-parabrachial neurons
Lamina I spino-parabrachial neurons (SPNs) receive peripheral nociceptive input, process it and transmit to the supraspinal centres. Although responses of SPNs to cutaneous receptive field stimulations have been intensively studied, the mechanisms of signal processing in these neurons are poorly understood. Therefore, we used an ex-vivo spinal cord preparation to examine synaptic and cellular mechanisms determining specific input-output characteristics of the neurons. The vast majority of the SPNs received a few direct nociceptive C-fiber inputs and generated one spike in response to saturating afferent stimulation, thus functioning as simple transducers of painful stimulus. However, 69% of afferent stimulation-induced action potentials in the entire SPN population originated from a small fraction (19%) of high-output neurons. These neurons received a larger number of direct Ad- and C-fiber inputs, generated intrinsic bursts and efficiently integrated a local network activity via NMDA-receptor-dependent mechanisms. The high-output SPNs amplified and integrated the nociceptive input gradually encoding its intensity into the number of generated spikes. Thus, different mechanisms of signal processing allow lamina I SPNs to play distinct roles in nociception.The authors thank Mr. Andrew Dromaretsky for the technical assistance. P.B. was supported by the National Academy of Sciences of Ukraine (NASU), grant NASU # 0116U004470, grant NASU#67/15-Н. N.V. was supported by the NASU Biotechnology and NASU-KNU grants; NIH 1R01NS113189-01. B.V.S. was supported by the FEDER funds through the COMPETE 2020 (POCI), Portugal 2020, and by the FCT project PTDC/NEU-NMC/1259/2014 (POCI-01-0145-FEDER-016588
Measurement of intracellular concentration of fluorescently-labeled targets in living cells
Estimations of intracellular concentrations of fluorescently-labeled molecules within living cells are very important for guidance of biological experiments and interpretation of their results. Here we propose a simple and universal approach for such estimations. The approach is based upon common knowledge that the dye fluorescence is directly proportional to its quantum yield and the number of its molecules and that a coefficient of proportionality is determined by spectral properties of the dye and optical equipment used to record fluorescent signals. If two fluorescent dyes are present in the same volume, then a ratio of their concentrations is equal to a ratio of their fluorescence multiplied by some dye- and equipment-dependent coefficient. Thus, if the coefficient and concentration of one dye is known then the concentration of another dye can be determined. Here we have demonstrated how to calculate this coefficient (called a ratio factor) and how to use it for concentration measurements of fluorescently tagged molecules. As an example of how this approach can be used, we estimated a concentration of exogenously expressed neuronal Ca2+ sensor protein, hippocalcin, tagged by a fluorescent protein in a dendritic tree of rat hippocampal neurons loaded via a patch pipette with Alexa Fluor dye of known concentration. The new approach should allow performing a fast, inexpensive and reliable quantitative analysis of fluorescently-labeled targets in different parts of living cells
Complex experiment on studying the microphysical, chemical, and optical properties of aerosol particles and estimating the contribution of atmospheric aerosol-to-earth radiation budget
The primary objective of this complex aerosol experiment was the measurement of microphysical, chemical, and optical properties of aerosol particles in the surface air layer and free atmosphere. The measurement data were used to retrieve the whole set of aerosol optical parameters, necessary for radiation calculations. Three measurement cycles were performed within the experiment during 2013: in spring, when the aerosol generation is maximal; in summer (July), when atmospheric boundary layer altitude and, hence, mixing layer altitude are maximal; and in late summer/early autumn, during the period of nucleation of secondary particles. Thus, independently obtained data on the optical, meteorological, and microphysical parameters of the atmosphere allow intercalibration and inter-complement of the data and thereby provide for qualitatively new information which explains the physical nature of the processes that form the vertical structure of the aerosol field
Study of fertility and cytogenetic variability in androgenic plants (R0 and R1) of alloplasmic introgression lines of common wheat
Anther culture is one of the methods to obtain DH lines of wheat. A limitation of this method can be cytogenetic instability in plants R0, leading to a decrease in fertility or sterility. In this study, we have investigated the fertility of R0, the fertility and cytogenetic variability of R1 in alloplasmatic introgression lines of common wheat in order to develop a cytogenetically stable DH lines with introgressions from different species. Lines 311/134, 311/FL, 311/IR with the cytoplasm from H. vulgare were studied. 311/134 carries the wheat-rye 1RS.1BL and wheatwheatgrass 7DL-7Ai translocations; 311/FL has the 1RS.1BL translocation and probably introgressions from A. glaucum; and 311/IR has the wheat-rye 1RS.1BL and wheat-Ae. speltoides T2B/2S#2 translocations. Green seedlings developed in anther culture for all lines. Differences between the lines in the ability for androgenesis and in the level of fertility in R0 and R1 have been revealed. Depressed androgenesis, low fertility and high aneuploidy were observed in 311/IR. It has been proposed that the reason for this is cytogenetic instability in gametes, which is caused by Gc genes located on T2B/2S#2. 63.3 % of 311/134 and 311/FL R1 plants that were grown from low seed-set R0 plants were aneuploids. Fertile R0 regenerant plants were identified that segregated in R1 for fertility and chromosome numbers. It has been demonstrated that DH lines are best developed from highfertility R1 plants with 2n = 42 irrespective of fertility in R0
Alloplasmic recombinant lines (H. vulgare)-T. aestivum with 1RS.1BL translocation: initial genotypes for production of common wheat varieties
Alloplasmic lines are formed when the cytoplasm of one species is replaced by the cytoplasm of another as a result of repeated recurrent crosses of wide hybrids with the paternal genotype. Since the cytoplasm replacement results in new intergenomic interactions between a nucleus and cytoplasm leading to variability of plant characteristics, alloplasmic lines with restored fertility can be an additional source of biodiversity of cultivated plants. Earlier, recombinant alloplasmic lines (H. vulgare)-T. aestivum designated as L-17(1)–L-17(37) were formed from a plant with partially restored fertility of the BC3 generation of barley-wheat hybrid H. vulgare (cv. Nepolegayushchii) × T. aestivum (cv. Saratovskaya 29). This male-sterile hybrid was consistently backcrossed with wheat varieties Mironovskaya 808 (twice) and Saratovskaya 29, and Mironovskaya 808 had a positive impact on the restoration of fertility. This paper presents the results of investigation into a group of recombinant alloplasmic lines (L-17F4), as well as into doubled haploids (DH) lines – alloplasmic DH-17-lines obtained from anther culture of alloplasmic lines (L-17F2). The most productive of these lines were used as initial breeding genotypes. Hybrid form Lutescens 311/00-22 developed from the crossing of the alloplasmic DH(1)-17 line (as maternal genotype) with euplasmic line Com37 (CIMMYT), the source of the 1RS.1BL wheat-rye translocation, proved to be successful for breeding. The presence of the 1RS.1BL translocation in the genome of the Lutescens 311/00-22 form and the L-311(1)–L-311(6) alloplasmic lines isolated from it did not lead to a decrease of fertility or sterility in the plants. This indicates that the chromosome of the 1BS wheat does not carry the gene(s) that determine the restoration of fertility in the studied (H. vulgare)-T. aestivum alloplasmic lines. Alloplasmic lines L-311(1)–L-311(6) showed their advantage in comparison with the standard varieties for resistance to leaf and stem rust, yield, and grain quality. The breeding tests performed at Omsk Agricultural Scientific Center, Agrocomplex “Kurgansemena”, Federal State Unitary Enterprise “Ishimskoe” (Tyumen Region), using alloplasmic lines L-311(5), L-311(4) and L-311(6) resulted in varieties of spring common wheat Sigma, Uralosibirskaya 2 and Ishimskaya 11, respectively
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