排序方式: 共有4814条查询结果,搜索用时 15 毫秒
971.
In a series of experiments on regulated contractile systems (i.e., in vitro mobile systems with reconstructed thin filaments), the velocities of the movement of a thin filament on the surface covered by either rabbit skeletal or rat cardiac myosin at various concentrations of calcium ions in solution (in the pCa range from 4 to 8) were assessed. The corresponding "pCa-velocity" relationships were plotted, which proved to be of the sigmoid form. It was found that, at a saturating calcium concentration (pCa 4), the velocity of regulated thin filaments was 65% higher than for unregulated ones in the case of skeletal myosin and 87% higher than for unregulated thin filaments in the case of cardiac myosin. It was also found that the Hill coefficient was 1.95 and 2.5 for skeletal and cardiac myosins, respectively. The difference in the Hill coefficients for skeletal and cardiac myosins is discussed in terms of the difference in contribution of cooperativity mechanisms of contractile and regulatory proteins in the regulation of contraction in these types of muscles. 相似文献
972.
Ivanov VK Tsyb AF Vasilenko EK Panfilov AP Kaĭdalov OV Korelo AM God'ko AM Tumanov KA Kashcheeva PV 《Radiatsionnaia biologiia, radioecologiia / Rossi?skaia akademiia nauk》2006,46(6):645-653
The draft new recommendations of the ICRP emphasize the need for transition from the collective dose to the dose matrix concept with optimization of the radiation protection system. In fact, this means assessment of the attributive (radiation-induced) risk at individual level with allowance for the dynamics of dose accumulation during the whole length of professional experience. The work provides assessments for high potential risk group from the "Mayak" personnel based on the dose matrix and using the UNSCEAR technique for assessing the attributive risk. It was found that about 2% of "Mayak" personnel subject to individual dosimetric monitoring in 2005 can be attributed to this group. 相似文献
973.
Anisimov VN Khavinson VKh Zavarzina NIu Zabezhinskiĭ MA Zimina OA Popovich IG Shtylik AV Arutiunian AV Oparina TI Prokopenko VM 《Rossi?skii fiziologicheski? zhurnal imeni I.M. Sechenova / Rossi?skaia akademiia nauk》2001,87(1):125-136
Female CBA mice were injected with s.c. synthetic tetrapeptide Epithalon from a 6-month age until death. The drug failed to affect the body weight or food consumption, physical activity or behavioural parameters. However, it slowed down the age-related switching off of the estrus function, decreased body temperature, decelerated free redical processes, prolonged the mice life span with an accompanying drop in spontaneous tumour incidence. 相似文献
974.
The bacterial hemoglobin vhb gene was cloned from sliding bacterium Vitreoscilla sp. as an element of the system ensuring survival of this microorganism in an environment that contains insufficient amount of oxygen. The vhb gene was transferred from Escherichia coli to some Streptomyces strains, producers of antibiotics, by the method of intergeneric conjugation using conjugative-integrative plasmid vectors pIH1 and pCH2. The stability of plasmid DNA inheritance was analyzed in the genomes of exconjugants. A positive effect of the vhb gene on processes of conjugation and antibiotic production in a number of examined strains was shown. 相似文献
975.
Vaĭner AS Boiarskikh UA Voronina EN Selezneva IA Sinkina TV Lazarev AF Petrova VD Filipenko ML 《Molekuliarnaia biologiia》2010,44(5):816-823
Breast cancer is the most incident cancer among women. We investigated the role of polymorphisms of folate metabolizing genes MTHFR (C677T and A1298C), SHMT1 (C1420T) and MTHFD (G1258A) in genetic susceptibility to this type of cancer. We determined allele and genotype frequencies in case (850 women with sporadic form of breast cancer) and control (810 women) groups. None of these polymorphisms was significantly associated with breast cancer risk. To increase statistical power of our study, we conducted a meta-analysis which included published genotype data and the results of our work. Meta-analysis also revealed no significant association of studied SNPs with breast cancer. 相似文献
976.
Kazakova OB Giniiatullina GV Tolstikov GA Baĭkova IP Zaprutko L Apryshko GN 《Bioorganicheskaia khimiia》2011,37(3):414-424
The synthesis of aminopropoxy derivatives of betulin, erythrodiol, uvaol and oleantriol via cyanoethylation of triterpenoids hydroxyl groups and subsequent reduction of cyanoethyl fragments is described. High and specific in vitro antitumor activity (cytotoxicity) of 3beta,28-di-O-[3-(aminopropoxy)]lupa-20(29)-ene and 3beta-O-hydroxy-28-O-[3-(aminopropoxy)]olean-12-ene towards a wide range of human tumor cell lines is discovered. The aminopropoxy group is shown to be a new perspective pharmacophor group for design of anticancer agents on the basis of triterpenoids. 相似文献
977.
978.
E. V. Grabovskiĭ P. R. Levashov G. M. Oleĭnik C. L. Olson P. V. Sasorov V. P. Smirnov S. I. Tkachenko K. V. Khishchenko 《Plasma Physics Reports》2006,32(9):718-728
Results are presented from studies of the possibility of using a thin metal foil for recyclable vacuum transmission lines with magnetic insulation in a conceptual fusion reactor based on high-voltage high-current electromagnetic generators. Numerical simulations and experiments in the Angara-5-1 facility were carried out to determine both the threshold for the explosion of a foil heated by a current pulse and the parameters of the plasma layer formed at the foil surface. It was found experimentally that an additional plasma current channel forms on the surface of a 120-μm stainless-steel foil at a linear current density of 0.25–0.5 MA/cm, which corresponds to a magnetic field of 0.3–0.6 MG. For the same conditions, one-dimensional computer simulations of the foil heating were performed in an MHD model by using a wide-range semiempirical equation of state for stainless steel. The calculated threshold for plasma generation on the foil surface is compared with the experimental data. The main parameters of the plasma layer are also calculated at linear current densities of 2–10 MA/cm, which far exceed the threshold current density. The plasma layer parameters as functions of the linear current density are determined for the case of an iron foil. 相似文献
979.
Mileĭkovskiĭ BY Nozdrachev AD 《Rossi?skii fiziologicheski? zhurnal imeni I.M. Sechenova / Rossi?skaia akademiia nauk》1997,83(5-6):80-93
Reactions of 277 neurones located in the brain pons dorsolateral portion were analised in staying awake and narcotized rats during immobility reflex, induced by the skin constriction on the neck dorsal surface. Got excited: fast adaptive tactile neurons (n = 32), interneurons (n = 42), and cells forming monosynaptic inputs to the parts of medulla oblongata, which inhibit the movements (n = 10). Were inhibited: somatosensory (n = 42), nociceptive (n = 24) and nonidentificated (n = 14) neurons. In some neurons charge characteristics were stable or slightly modified, namely: respiratory neurons (n = 16), cell group, having stable background firing (n = 72) and stimulating antidromically spontaneously silent ponto-medullar neurons (n = 22). 相似文献
980.
Shandra AA Godlevskiĭ LS Brusentsov AI Vast'ianov RS Karliuga VA Dzygal AF Nickel B 《Rossi?skii fiziologicheski? zhurnal imeni I.M. Sechenova / Rossi?skaia akademiia nauk》1997,83(3):95-99
An anti-ischemic effect of the delta-sleep-inducing peptide (DSIP) was found in rats. The DSIP effect was more obvious than that of the MK-801. The data obtained is discussed considering a possible use of the DSIP for brain stroke prophylaxis. 相似文献