215 research outputs found

    Cool spots on the surface of the active giant PZ Mon

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    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

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    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

    Distinct mechanisms of signal processing by lamina I spino-parabrachial neurons

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    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

    Wildfire smoke in the Siberian Arctic in summer: source characterization and plume evolution from airborne measurements

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    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>−3</sup> and the EBC content reached 1.4 μg m<sup>−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 ± 3% based on CO and CO<sub>2</sub> measurements and a CO emission factor of 65.5 ± 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 ± 0.07 g BC kg<sup>−1</sup>, comparable to values reported in the literature. The emission ratio of ultra-fine particles (3.5–200 nm) was 26 cm<sup>−3</sup> (ppb CO)<sup>−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

    Measurement of intracellular concentration of fluorescently-labeled targets in living cells

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    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

    The perspective soft spring wheat variety Semenovna is the result of international cooperation

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    The research is aimed at studying economically valuable traits and genetic control of resistance to leaf-stem diseases, photoperiodic reaction and short stemming of soft spring wheat variety Semenovna, created by scientists of the Omsk Agrarian Scientific Center (Russia) and the North Kazakhstan Agricultural Experimental Station (Kazakhstan). Using methods of state variety testing, molecular genetics and in vitro methods, morphological features of a new variety, features of its development have been described, the yield level at different ecological test points for three years (2015-2017) has been analyzed. The studies conducted at two ecological points made it possible to select a medium-sized promising line of soft spring wheat (Lutescens 354/04-6), which was transferred to the State Registration Service of the Republic of Kazakhstan and after two years of testing was included into the State Register of the Republic of Kazakhstan under the name Semenovna (patent No. 1023). In terms of grain quality, it was at the level of valuable wheat, exceeded the standard in protein content by 1-2 % and raw gluten by 3-4 %. The new medium-ripe Semenovna variety combines increased yield (2.73-4.40 t/ha) with resistance to drought (resistance index Ir = 0.57), brown and stem rust (IU = 0.00-0.23). The genotype of the variety contains wheat-rye translocation 1RS.1BL (with a cluster of Lr26/Sr31/Pm8/Yr9 genes). The medium-stem variety carries the Rht8b allele in its genotype (174 bp)  and is photosensitive to the length of the day (allele 414 bp). The parameters of ecological plasticity of the new variety are determined: linear regression coefficient (bi = 1.08), stability index (σd2 = 0.27)

    Study of fertility and cytogenetic variability in androgenic plants (R0 and R1) of alloplasmic introgression lines of common wheat

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    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
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