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81.
Brylev V. A. Lysenko I. L. Kokin E. A. Martynenko-Makaev Y. V. Ryazantsev D. Y. Shmanai V. V. Korshun V. A. 《Russian Journal of Bioorganic Chemistry》2021,47(3):734-740
Russian Journal of Bioorganic Chemistry - An azido-derivative of a fluorescein bifluorophore was obtained and used for the synthesis of “molecular beacon”-type oligonucleotide... 相似文献
82.
K. A. Razumova V. F. Andreev I. S. Bel’bas A. V. Gorshkov A. Yu. Dnestrovskij K. S. Dyabilin A. Ya. Kislov S. E. Lysenko G. E. Notkin N. N. Timchenko A. N. Chudnovskiy D. A. Shelukhin 《Plasma Physics Reports》2013,39(9):691-697
Results are presented from experiments on the formation of an internal electron transport barrier near the q = 1.5 rational surface in the T-10 tokamak. The experiments were carried out in the regime with off-axis electron cyclotron resonance (ECR) heating followed by a fast plasma current ramp-up. After suppressing sawtooth oscillations by off-axis ECR heating, an internal transport barrier began to form near the q = 1.5 rational surface. In the phase of the current ramp-up, the quality of the transport barrier improved; as a result, the plasma energy confinement time increased 2–2.5 times. The intentionally produced flattening of the profile of the safety factor q(r) insignificantly affected magnetohydrodynamic activity in the plasma column in spite of the theoretical possibility of formation of substantial m/n = 3/2 and 2/1 magnetic islands. Conditions are discussed under which the flattening of the profile of the safety factor q near low-order rational surfaces leads to the formation of either an internal transport barrier or the development of an island magnetic structure induced by tearing modes. 相似文献
83.
Lorena Fuentes-Broto Enrique Martínez-Ballarín Javier Miana-Mena Cesar Berzosa Eduardo Piedrafita Igor Cebrián 《Free radical research》2013,47(11):1080-1089
Cholestasis occurs in a variety of hepatic diseases and causes damage due to accumulation of bile acids in the liver. The aim was to investigate the effect of several bile acids, i.e. chenodeoxycholic, taurochenodeoxycholic, deoxycholic, taurodeoxycholic, ursodeoxycholic, lithocholic and taurolithocholic (TLC), in inducing oxidative damage. Hepatic tissue of male Sprague-Dawley rats was incubated with or without 1 mM of each bile acid, with or without 0.1 mM FeCl3 and 0.1 mM ascorbic acid for the purpose of generating free radicals. Several bile acids increased lipid and protein oxidation, with TLC being the most pro-oxidative (657% and 175% in homogenates and 350% and 311% in membranes, respectively). TLC also enhanced iron-induced oxidative stress to lipids (21% in homogenates and 29% in membranes) and to proteins (74% in membranes). This enhancement was dose- and time-dependent and was reduced by melatonin. These results suggest that bile acids differentially mediate hepatic oxidative stress and may be involved in the physiopathology of cholestasis. 相似文献
84.
Vincent?Koppelmans Burak?Erdeniz Yiri?E?De Dios Scott?J?Wood Patricia?A?Reuter-Lorenz Igor?Kofman Jacob?J?Bloomberg Ajitkumar?P?Mulavara Rachael?D?Seidler
Background
Long duration spaceflight (i.e., 22 days or longer) has been associated with changes in sensorimotor systems, resulting in difficulties that astronauts experience with posture control, locomotion, and manual control. The microgravity environment is an important causal factor for spaceflight induced sensorimotor changes. Whether spaceflight also affects other central nervous system functions such as cognition is yet largely unknown, but of importance in consideration of the health and performance of crewmembers both in- and post-flight. We are therefore conducting a controlled prospective longitudinal study to investigate the effects of spaceflight on the extent, longevity and neural bases of sensorimotor and cognitive performance changes. Here we present the protocol of our study.Methods/design
This study includes three groups (astronauts, bed rest subjects, ground-based control subjects) for which each the design is single group with repeated measures. The effects of spaceflight on the brain will be investigated in astronauts who will be assessed at two time points pre-, at three time points during-, and at four time points following a spaceflight mission of six months. To parse out the effect of microgravity from the overall effects of spaceflight, we investigate the effects of seventy days head-down tilted bed rest. Bed rest subjects will be assessed at two time points before-, two time points during-, and three time points post-bed rest. A third group of ground based controls will be measured at four time points to assess reliability of our measures over time. For all participants and at all time points, except in flight, measures of neurocognitive performance, fine motor control, gait, balance, structural MRI (T1, DTI), task fMRI, and functional connectivity MRI will be obtained. In flight, astronauts will complete some of the tasks that they complete pre- and post flight, including tasks measuring spatial working memory, sensorimotor adaptation, and fine motor performance. Potential changes over time and associations between cognition, motor-behavior, and brain structure and function will be analyzed.Discussion
This study explores how spaceflight induced brain changes impact functional performance. This understanding could aid in the design of targeted countermeasures to mitigate the negative effects of long-duration spaceflight.85.
Gary Voelker Georgy Semenov Igor V. Fadeev Anna Blick Sergei V. Drovetski 《分类学与生物多样性》2013,11(3):296-305
Montane areas host high levels of diversity and endemism, and these features are tied to habitat stratification along an elevational gradient. As such, montane areas are often thought of as model systems in which sympatric speciation can occur. To test this idea, we selected Phoenicurus redstarts, an avian genus with an extensive distribution across Eurasia, as well as Northwest Africa; nine of the 14 species in the genus have distributions which include the Himalayas. We used sequences of the mtDNA ND2 and cytochrome-b genes and intron 9 of the Z chromosome specific ACO1 gene to reconstruct a phylogeny of the genus. The resulting trees were used to reconstruct a biogeographic history of Phoenicurus, and to date diversification events. We also analysed the relationship between node age and sympatry to determine the geographic mode of speciation in the genus. Our data suggest a very late Miocene, Himalayan origin for Phoenicurus. Diversification and colonization of other parts of Eurasia, as well as Northwest Africa, continued through the Pleistocene, with a rapid pulse of speciation in the late Pliocene. Allopatric speciation was the dominant mode of speciation in Phoenicurus, despite extensive distributional overlaps in the Himalayas where ecological conditions are amenable to speciation in sympatry. Our results, along with several other studies, suggest an emerging pattern where the Himalayas served as a source area for montane specialist avian lineages that subsequently colonized other Palaearctic regions. 相似文献
86.
Maksim V. Kvach Igor A. Prokhorenko Alexey V. Ustinov Sergei V. Gontarev Vladimir A. Korshun Vadim V. Shmanai 《Nucleosides, nucleotides & nucleic acids》2013,32(6-7):809-813
New reagents (CPGs and phosphoramidites) for automatic solid phase synthesis of modified oligonucleotides were designed. Three oligonucleotides carrying fluorescent label at the 5′-terminus and an anchor group at the 3′-terminus were prepared and their immobilization in orthogonal conditions on solid supports was studied. 相似文献
87.
Andrzej Oleksa Igor J. Chybicki Robert Gawroński Glenn P. Svensson Jaroslaw Burczyk 《Journal of Insect Conservation》2013,17(2):219-233
Species confined to temporally stable habitats are usually susceptible to habitat fragmentation, as living in long-lasting habitats is predicted to constrain evolution of dispersal ability. In Europe, saproxylic invertebrates associated with tree hollows are currently threatened due to the severe fragmentation of their habitat, but data on the population genetic consequences of such habitat decline are still scarce. By employing AFLP markers, we compared the spatial genetic structure of two ecologically and taxonomically related beetle species, Osmoderma barnabita and Protaetia marmorata (Cetoniidae). Both species are exclusively associated with tree hollows, but O. barnabita has a more restricted host preferences compared to P. marmorata. Analyses of spatial autocorrelation showed, in line with the predicted low dispersal potential of these saproxylic beetles, that both species are characterized by a strong kinship structure, which was more pronounced in the specialist O. barnabita than in the generalist P. marmorata. Individuals of both species sampled within single trees showed high relatedness (≈0.50 in O. barnabita and ≈0.15 in P. marmorata). Interestingly, groups of pheromone-emitting O. barnabita males sampled on the same tree trunk were found to be full brothers. Whether this result can be explained by kin selection to increase attraction of conspecific females for mating or by severe inbreeding of beetles within individual tree hollows needs further study. Although our studied populations were significantly inbred, our results suggest that the dispersal ability of Osmoderma beetles may be one order of magnitude greater than suggested by previous dispersal studies and acceptable levels of habitat fragmentation for metapopulation survival may be bigger than previously thought. 相似文献
88.
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90.
Yahya Sohrabi Helena Havelková Tetyana Kobets Matyá? ?íma Valeriya Volkova Igor Grekov Ta?ána Jaro?íková Iryna Kurey Jarmila Vojtí?ková Milena Svobodová Peter Demant Marie Lipoldová 《PLoS neglected tropical diseases》2013,7(7)