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排序方式: 共有327条查询结果,搜索用时 15 毫秒
21.
Dubovaia VG Fesenko SV 《Radiatsionnaia biologiia, radioecologiia / Rossi?skaia akademiia nauk》2001,41(2):210-216
The regularities of changes in factors of 137Cs transfer to natural and sown grasses in the longterm period after the Chernobyl accident are described. The dynamics of changes in factors of 137Cs transfer to sown grasses over the period of 1993 to 1999 was of a non-uniform character. On average, these transfer factors (TF) tended to decrease in that period. A significant tendency for an increase in TF to sown grasses was noted for 1997-1999. The half-life periods of decrease in TF to natural grasses in the period 1993-1999 were shown to be ranged from 4.6 to 24.6 years. It was demonstrated that the differences in the TF dynamics between sown and natural grasses were related to the peculiarities of their development and application of countermeasures. 相似文献
22.
Telomeres, DNA-protein structures, are important elements of the eukaryotic chromosome. Telomeric regions of the majority of higher plants contain heptanucleotides TTTAGGG arranged into a tandem repeat. However, some taxa have no such repeats. These are some species of lilies (Lilium) and onions (Allium). For example, terminal regions of chromosomes of Spanish onion (Allium fistulosum) contain satellite DNA whose unit repeats are 380 bp in length, and the short arm of its chromosome 8 contains rDNA repeats. This study deals with the terminal heterochromatin and organization of the satellite repeat in A. fistulosum. Fluorescent in situ hybridization (FISH) was used to locate the satellite DNA on chromosomes and on extended DNA of A. fistulosum. Nonsatellite DNA was found in the structure of telomeric repeat. Polymerase chain reaction (PCR) and Southern hybridization were used for analysis of terminal heterochromatin. Various rearrangements were found in the satellite repeat. The roles of retrotransposones and microsatellites in the formation of terminal heterochromatin are discussed. 相似文献
23.
Fesenko SV Panov AV 《Radiatsionnaia biologiia, radioecologiia / Rossi?skaia akademiia nauk》2002,42(1):100-109
A comparative analysis of the strategy of countermeasures aimed at reducing exposure doses to the rural population is presented. The effectiveness of the proposed system of countermeasures assessed by criteria such as reduction factor of exposure doses and cost of averted doses. Costs of countermeasures in the rural settlements located in the affected zone are calculated for a long term after the Chernobyl NPP accident. 相似文献
24.
It was shown that preliminary treatment of the protein component (histone H3, protamine sulfate, polyarginine) of a DNA-protein complex with weak combined (42 microT) and low-frequency (3.5-5.0 Hz) alternating (0.06 microT) magnetic fields adjusted formally to the cyclotron resonance of amino acid ions charged under natural conditions leads to substantial changes in complex formation and formation of complexes of a different type than without treatment. 相似文献
25.
Fleming TP Papenbrock T Fesenko I Hausen P Sheth B 《Seminars in cell & developmental biology》2000,11(4):291-299
Tight junction formation during development is critical for embryonic patterning and organization. We consider mechanisms of junction biogenesis in cleaving mouse and Xenopus eggs. Junction assembly follows the establishment of cell polarity at 8-cell (mouse) or 2-cell (Xenopus) stages, characterized by sequential membrane delivery of constituents, coordinated by embryonic (mouse) or maternal (Xenopus) expression programmes. Cadherin adhesion is permissive for tight junction construction only in the mouse. Occludin post-translational modification and membrane delivery, mediated by delayed ZO-1 alpha(+)isoform expression in the mouse, provides a mechanism for completion of tight junction biogenesis and sealing, regulating the timing of blastocoel cavitation. 相似文献
26.
27.
Yankovich TL Beresford NA Wood MD Aono T Andersson P Barnett CL Bennett P Brown JE Fesenko S Fesenko J Hosseini A Howard BJ Johansen MP Phaneuf MM Tagami K Takata H Twining JR Uchida S 《Radiation and environmental biophysics》2010,49(4):549-565
Environmental monitoring programs often measure contaminant concentrations in animal tissues consumed by humans (e.g., muscle). By comparison, demonstration of the protection of biota from the potential effects of radionuclides involves a comparison of whole-body doses to radiological dose benchmarks. Consequently, methods for deriving whole-body concentration ratios based on tissue-specific data are required to make best use of the available information. This paper provides a series of look-up tables with whole-body:tissue-specific concentration ratios for non-human biota. Focus was placed on relatively broad animal categories (including molluscs, crustaceans, freshwater fishes, marine fishes, amphibians, reptiles, birds and mammals) and commonly measured tissues (specifically, bone, muscle, liver and kidney). Depending upon organism, whole-body to tissue concentration ratios were derived for between 12 and 47 elements. The whole-body to tissue concentration ratios can be used to estimate whole-body concentrations from tissue-specific measurements. However, we recommend that any given whole-body to tissue concentration ratio should not be used if the value falls between 0.75 and 1.5. Instead, a value of one should be assumed. 相似文献
28.
Irina Fesenko Danielle Franklin Paul Garnett Paul Bass Sara Campbell Michelle Hardyman David Wilson Neil Hanley Jane Collins 《Histochemistry and cell biology》2010,134(4):355-369
The kidney has an intrinsic ability to repair itself when injured. Epithelial cells of distal tubules may participate in regeneration.
Stem cell marker, TRA-1-60 is linked to pluripotency in human embryonic stem cells and is lost upon differentiation. TRA-1-60
expression was mapped and quantified in serial sections of human foetal, adult and diseased kidneys. In 8- to 10-week human
foetal kidney, the epitope was abundantly expressed on ureteric bud and structures derived therefrom including collecting
duct epithelium. In adult kidney inner medulla/papilla, comparisons with reactivity to epithelial membrane antigen, aquaporin-2
and Tamm–Horsfall protein, confirmed extensive expression of TRA-1-60 in cells lining collecting ducts and thin limb of the
loop of Henle, which may be significant since the papillae were proposed to harbour slow cycling cells involved in kidney
homeostasis and repair. In the outer medulla and cortex there was rare, sporadic expression in tubular cells of the collecting
ducts and nephron, with positive cells confined to the thin limb and thick ascending limb and distal convoluted tubules. Remarkably,
in cortex displaying tubulo-interstitial injury, there was a dramatic increase in number of TRA-1-60 expressing individual
cells and in small groups of cells in distal tubules. Dual staining showed that TRA-1-60 positive cells co-expressed Pax-2
and Ki-67, markers of tubular regeneration. Given the localization in foetal kidney and the distribution patterns in adults,
it is tempting to speculate that TRA-1-60 may identify a population of cells contributing to repair of distal tubules in adult
kidney. 相似文献
29.
Spiridonov SI Aleksakhin RM Fesenko SV Sanzharova NI 《Radiatsionnaia biologiia, radioecologiia / Rossi?skaia akademiia nauk》2007,47(2):196-203
Analyzed information which describes a wide spectrum of the consequences of radioactive contamination of natural ecosystems by the Chernobyl accident. The main regularities of radionuclide migration in the environment was been considered and scales of radiation damage to biota assessed. The area where signs of direct damage to biota are visible is shown to be noticeably smaller in size that the area where radionuclide concentration in environmental objects is above the permissible levels. The importance of the impact of radioactive contamination of natural ecosystems is assessed in terms of formation of exposure doses to the population. The conclusion was made that the detriment from all the factors is larger for humans (direct irradiation, limitation of the economic activity, etc.) than for biota. 相似文献
30.
Panov AV Fesenko SV Aleksakhin RM Pasternak AD Prudnikov PV 《Radiatsionnaia biologiia, radioecologiia / Rossi?skaia akademiia nauk》2007,47(2):224-230
The effectiveness of countermeasures on private farms in rural settlements of the Russian Federation affected by the Chernobyl accident for the period of 1986-2005 was assessed. The averted collective doses to the residents of these settlements and the contribution of restrictive and agricultural countermeasures to dose reduction in the rural population have been estimated. 相似文献