Reactive oxygen species as a trigger of the infarct-limiting effects of early hypoxic preconditioning rat myocardium

It is believed that reactive oxygen species (ROS) are involved in the performance of this adaptive hepatoprotective effect phenomenon. However, the role of ROS in the signaling mechanism of the early hypoxic preconditioning (early HP) and the contribution of individual types of oxygen radicals in the infarct-limiting effect of early HP remains uncertain to the end. Objective was to investigate the role of various types of reactive oxygen species in the signaling mechanism of the infarct-limiting effect of early hypoxic preconditioning. We investigated the role of reactive oxygen species in the signaling mechanism of early HP in vivo. Adaptation of animals was conducted with 6 transient hypoxia-reoxygenation sessions before prolonged ischemia (45 min) and reperfusion (120 min). Low molecular weight antioxidants were administered 15 minutes prior to the HP. We found out that pretreatment with the nonselective antioxidant indirect action of N-(2-mercaptopropionyl)-glycine and "trap" of hydroxyl radicals 1,3-dimethylthiourea completely eliminated the infarct-limiting effect of adaptation. Administration of antioxidants tempol and trolox, as well as the use of N-(2-mercaptopropionyl)-glycine after HP had no effect on the protective effect of adaptation. Consequently, reactive oxygen species, including hydroxyl radical, operate as the trigger function in the signaling mechanism of early HP

A chronology of the Scythian antiquities of Eurasia based on new archaeological and C-14 data

The paper is compares the chronology of the monuments of the Scythian epoch located in the east and west of the Eurasian steppe zone on the basis of both archaeological and radiocarbon data. The lists of C-14 dates for the monuments located in different parts of Eurasia are presented according to the periods of their existence. Generally, the C-14 dates are confirmed the archaeological point of view and allow us to compare the chronological position of the European and Asian Scythian monuments on the united C-14 time scale

Some problems in the study of the chronology of the ancient nomadic cultures in Eurasia (9th - 3rd centuries BC)

This research is focused on the chronological investigations of ancient nomads belonging to the Scythian cultures which occupied the steppe and forest-steppe zones of Eurasia during the 9th-3rd centuries BC. The 14C dates for the pre-scythian and early scythian time in both Europe and Asia are presented and compared to their chronological position based on archaeological evidence. The first 14C dates have been produced for the Scythian time monuments located in the Lower Volga River basin, Urals and Transurals regions. Their chronological positions are compared with the position of the monuments of Southern Siberia and Central Asia. It was shown that the nomadic cultures belonging to the Scythian culture began to exist over the wide territory of Eurasia from the 9th-8th centuries cal BC and there are some monuments which may be synchronous to the Arzhan royal barrow (the oldest monument known). A list of new 14C dates and a map of the monuments are presented

Amplification of Frequency-Modulated Similariton Pulses in Length-Inhomogeneous Active Fibers

The possibility of an effective gain of the self-similar frequency-modulated (FM) wave packets is studied in the lengthinhomogeneous active fibers. The dynamics of parabolic pulses with the constant chirp has been considered. The optimal profile for the change of the group-velocity dispersion corresponding to the optimal similariton pulse amplification has been obtained. It is shown that the use of FM pulses in the active (gain) and length-inhomogeneous optical fibers with the normal group-velocity dispersion can provide subpicosecond optical pulse amplification up to the energies higher than 1 nJ

CMB Anisotropy Induced by a Moving Straight Cosmic String

We showed that the part of strings could be detected by optical method is only 20% from the total available amount of such objects, therefore the gravitational lensing method has to be "completed" by CMB one. We found the general structure of the CMB anisotropy generated by a cosmic string for simple model of straight string moving with constant velocity. For strings with deficit angle 1-2 arcsec the amplitude of generated anisotropy has to be 15-30 muK (the corresponding string linear density is (G mu) ~ 10^{-7} and energy is GUT one, 10^{15} GeV). To use both radio and optical methods the deficit angle has to be from 0.1 arcsec to 5-6 arcsec. If cosmic string can be detected by optical method, the length of corresponding brightness spot of anisotropy has to be no less than 100 degrees.Comment: 6 pages, 1 Postscript figure, will be published in proceedings of QUARKS-2008, 15th International Seminar on High Energy Physics, Sergiev Posad, Russia, 23-29 May, 200