121 research outputs found
Rate coefficients of exchange reactions accounting for vibrational excitation of reagents and products
No full textEffect of dipole orientation on Purcell factor for the quantum emitter near silicon nanoparticle
No full textCampsites of the Southern Urals Nomads in the Middle of the I Millennium BC (according to data from the Bannoye – Sabakty – Karabalykty Lake System)
No full textThe paper deals with the materials from three sites, namely the settlement Bannoye-5a (Berezki), Telyashevo-4 and Sabakty-3/5. They are discovered with ceramics of the early nomads (late V – late IV century BC). All these sites are situated within a narrow strip of mountain steppes along the eastern slope of the Southern Urals (modern Abzelilovsky district of the Republic of Bashkortostan). It is on the same latitude as Magnitogorsk. The settlement Bannoye-5a (Berezki) was studied in 1972–1976 and 2004–2005. The received materials were analyzed and showed three points of spread early nomadic ceramics. Two of them were revealed by excavations and are rather small in size. Also a similar situation was at Telyashevo-4 settlement. It is shown that all three sites can be interpreted as nomadic campsites. When the author analyzes all the information about the spread area of Southern Ural nomads in the middle of the I millennium BC, the author can conclude that the campsites and other types of settlements close to them were quite common (more than 30 sites are currently recorded). It is particularly complicated to find and register such kind of sites, however, studying them is the only way to learn something new about their household, spread and land development
On the Southern Border of the Forest and Forest-Steppe Cultures in the Urals in the Ist Millennium BC
No full textThe article demonstrates that the central part of South Ural Mountains with surrounding foot-hills was a special transzonal territory, where the natural conditions prevented development of homogenous and stable ethnic and cultural formations in the central part of the South-Ural region. In the I Millennium BC, this region accepted numerous groups of forest and northern forest-steppe population who continuously migrated here from the north and lived in the immediate vicinity to the steppe nomads. The author identified three main itineraries of such groups migrating to the south. A number of laws of interaction of forest and northern forest-steppe early Iron Age population was considered, both among themselves and with the nomads
Extracts of salvia species : relation to potential cognitive therapy
No full textBACKGROUND: Dementia is a neurodegenerative disease of the brain associated with cognitive and memory impairments. Despite recognition of several types of dementia, the Alzheimer type is the most studied and understood. The cholinergic theory of Alzheimer's disease led to the development of licensed drugs based on the inhibition of the enzyme acetylcholinesterase. Extracts of Salvia (sage) species have been reported to have cholinergic activities relevant to the treatment of Alzheimer's disease. AIMS: Lack of information on a chemical fingerprint of the extracts responsible for inhibition of the enzymes butyrylcholinesterase and acetylcholinesterase prompted this in vitro investigation of sage species for anti-cholinesterase activity. Cholinergic receptor binding activity, inhibition of ß-secretase, and a pro-inflammatory cytokine suppressive activity of extracts of sage species were also studied as relevant treatment targets. METHODS: The extracts were obtained by methods of supercritical fluid extraction using 1,1,1,2-tetrafluoroethane (Phytosol A) and steam distillation. Dose-dependant inhibition of human cholinesterases by the extracts and constituents was determined using the method of Ellman, while inhibition of ß-secretase via a fluorometric method. The nicotinic acetylcholine receptors binding activity was measured as an amount of [3H]-nicotine displaced from human acetylcholine receptors, whereas the muscarinic activity was assessed using the displacement of [3H]-scopolamine. Determination of interleukin 8 inhibitory activity by the extracts was performed via a quantitative sandwich enzyme immunoassay using a commercially available kit. RESULTS: Inhibition of butyrylcholinesterase by the Phytosol extracts of S. apiana, S. fruticosa and S. officinalis var. purpurea was non-competitive. In contrast, inhibition of acetylcholinesterase by S. officinalis var. purpurea oil was competitive. S. corrugata extract was the most potent inhibitor of acetylcholinesterase with an IC50 value of 0.009±0.004 mg ml", while S. officinalis var. purpurea oil was the most active inhibitor of butyrylcholinesterase with an IC50 value of 0.015±0.004 mg ml''. Time dependent increase in inhibition of butyrylcholinesterase by steam distilled oils of S. fruticosa and S. officinalis var. "purpurea" was also evident. IC50 values decreased from 0.15±0.007 and 0.14±0.007 mg ml-1 with 5 minutes to 0.035±0.016 and 0.06±0.018 mg ml-1 with 90 minutes incubation time respectively. Phytosol A extracts were more potent than steam distilled oils with respect to anti-cholinesterase activity. Minor synergy in inhibition of bovine acetylcholinesterase was apparent in 1,8-cineole/a-pinene and 1,8- cineole/caryophyllene oxide combinations, whereas a combination of camphor and 1,8- cineole was antagonistic. Oil of S. apiana displaced [3H]-nicotine from human nicotinic acetylcholine receptors and [3H]-scopolamine from muscarinic acetylcholine receptors in a dose dependent manner with IC50 values of 0.02 mg ml" and IC50 0.1 mg ml" respectively. This oil also showed a modest suppression of interleukin 8 secretions from goblet cells. None of the tested oils and constituents had anti-ß secretase activity. CONCLUSION: These findings demonstrate that the cholinergic activity of the extracts results from a complex interaction between their constituents. Thus, inhibition of acetylcholinesterase is mainly due to the activity of the main constituents with some degree of synergy, whereas anti-butyrylcholinesterase activity is down to major synergistic interactions and identification of a chemical fingerprint responsible for the overall activity is therefore challenging. A synergistic combination of extracts or their standardised fractions with multiple activities is may be a candidate for clinical trials in Alzheimer's disease.EThOS - Electronic Theses Online ServiceGBUnited Kingdo
Individual variation in 3-methylbutanal: A putative link between human leukocyte antigen and skin microflora
No full textThe human derma emits volatile compounds whose interaction with a receiver's olfactory sensory system may affect individual recognition and mating preferences. Studies suggest that both genes and environmental factors determine characteristic odor of an individual. Here, we use solid phase micro-extraction and GC-MS to identify 3-methylbutanal (3-MB) in human axillary odor, show that the abundance of this volatile compound varies significantly between individuals and demonstrate in vitro that its formation may be influenced by interaction between human leukocyte antigen peptide and dermal microflora
Unidirectional coupling of a quantum emitter to a subwavelength grating waveguide with engineered stationary inflection point
No full textIn this work, we propose an approach for the design of a waveguide structure that allows for efficient and highly asymmetric coupling of the quantum sources with circularly polarized transition dipole moments to the guided mode of the structure. The approach is based on the mixing of the two quasi-degenerate modes of a periodic waveguide with an auxiliary single-mode waveguide leading to the formation of the dispersion with a stationary inflection point and consequently to the high coupling efficiency of this mode with a dipole source. We show that the distribution of the field polarization inside the waveguide is relatively homogeneous maintaining the circular polarization in a large area. Consequently, this leads to a high degree of tolerance of the coupling asymmetry and strength to the position of the quantum emitter. We believe, that our results will extend the variety of designs of the efficient chiral nanophotonic interfaces based on planar semiconductor nanostructures
Shifts in the Genetic Landscape of the Western Eurasian Steppe Associated with the Beginning and End of the Scythian Dominance
No full textThe Early Iron Age nomadic Scythians have been described as a confederation of tribes of different origins, based on ancient DNA evidence [1–3]. It is still unclear how much of the Scythian dominance in the Eurasian Steppe was due to movements of people and how much reflected cultural diffusion and elite dominance. We present new whole-genome sequences of 31 ancient Western and Eastern Steppe individuals, including Scythians as well as samples pre- and postdating them, allowing us to set the Scythians in a temporal context (in the Western, i.e., Ponto-Caspian Steppe). We detect an increase of eastern (Altaian) affinity along with a decrease in eastern hunter-gatherer (EHG) ancestry in the Early Iron Age Ponto-Caspian gene pool at the start of the Scythian dominance. On the other hand, samples of the Chernyakhiv culture postdating the Scythians in Ukraine have a significantly higher proportion of Near Eastern ancestry than other samples of this study. Our results agree with the Gothic source of the Chernyakhiv culture and support the hypothesis that the Scythian dominance did involve a demic component. Järve et al. present 31 ancient Scythians and samples from pre- and postdating cultures from the Eurasian Steppe. An increase of eastern ancestry in the steppe during the Scythian period supports some demic diffusion in the spread of the Scythian culture. The genetic makeup of post-Scythian Chernyakhiv individuals agrees with their Gothic source
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