The paper presents research results of the copper smelting furnace at the turn of the 3rd/2nd millennium BC discovered in the ancient mine Novotemirsky. This is the first evidence of the metals ...smelting from ores directly at the deposit in the Bronze Age of the Southern Trans- Urals. The technology of smelting metals from ores (the furnace structure, the type of ores and slags, the melting temperature, and the metal composition) was determined using a complex of mineralogical and geochemical research methods (optical and electron microscopy, X-ray diffraction, X-ray fluorescence analysis and LA-ICP-MS)., The results demonstrate an original metallurgical technology despite the territorial-chronological localization of the furnace within the Sintashta culture. In particular, sulfide inclusions in the Cr-rich containing olivine slags find analogies in the Abashevo culture from multilayer Bronze Age settlements of the Southern Urals.
The pyrite nodules from ore diagenites of the Urals massive sulfide deposits associated with various background sedimentary rocks are studied using optical and electron microscopy and LA-ICP-MS ...analysis. The nodules are found in sulfide–black shale, sulfide–carbonate–hyaloclastite, and sulfide–serpentinite diagenites of the Saf’yanovskoe, Talgan, and Dergamysh deposits, respectively. The nodules consist of the core made up of early diagenetic fine-crystalline (grained) pyrite and the rim (±intermediate zone) composed of late diagenetic coarse-crystalline pyrite. The nodules are replaced by authigenic sphalerite, chalcopyrite, galena, and fahlores (Saf’yanovskoe), sphalerite, chalcopyrite and galena (Talgan), and pyrrhotite and chalcopyrite (Dergamysh). They exhibit specific accessory mineral assemblages with dominant galena and fahlores, various tellurides and Co–Ni sulfoarsenides in sulfide-black shale, sulfide–hyaloclastite–carbonate, and sulfide-serpentinite diagenites, respectively. The core of nodules is enriched in trace elements in contrast to the rim. The nodules from sulfide–black shale diagenites are enriched in most trace elements due to their effective sorption by associated organic-rich sediments. The nodules from sulfide–carbonate–hyaloclastite diagenites are rich in elements sourced from seawater, hyaloclastites and copper–zinc ore clasts. The nodules from sulfide–serpentinite diagenites are rich in Co and Ni, which are typical trace elements of ultramafic rocks and primary ores from the deposit.
We analyze the behavior of the parsec-scale jet of the quasar 3C 454.3 during pronounced flaring in 2005-2008. Three major disturbances propagated down the jet along different trajectories with ...Lorentz factors {Gamma} > 10. The disturbances show a clear connection with millimeter-wave outbursts, in 2005 May/June, 2007 July, and 2007 December. High-amplitude optical events in the R-band light curve precede peaks of the millimeter-wave outbursts by 15-50 days. Each optical outburst is accompanied by an increase in X-ray activity. We associate the optical outbursts with propagation of the superluminal knots and derive the location of sites of energy dissipation in the form of radiation. The most prominent and long lasting of these, in 2005 May, occurred closer to the black hole, while the outbursts with a shorter duration in 2005 autumn and in 2007 might be connected with the passage of a disturbance through the millimeter-wave core of the jet. The optical outbursts, which coincide with the passage of superluminal radio knots through the core, are accompanied by systematic rotation of the position angle of optical linear polarization. Such rotation appears to be a common feature during the early stages of flares in blazars. We find correlations between optical variations and those at X-ray and {gamma}-ray energies. We conclude that the emergence of a superluminal knot from the core yields a series of optical and high-energy outbursts, and that the millimeter-wave core lies at the end of the jet's acceleration and collimation zone. We infer that the X-ray emission is produced via inverse Compton scattering by relativistic electrons of photons both from within the jet (synchrotron self-Compton) and external to the jet (external Compton, or EC); which one dominates depends on the physical parameters of the jet. A broken power-law model of the {gamma}-ray spectrum reflects a steepening of the synchrotron emission spectrum from near-IR to soft UV wavelengths. We propose that the {gamma}-ray emission is dominated by the EC mechanism, with the sheath of the jet supplying seed photons for {gamma}-ray events that occur near the millimeter-wave core.
We analyze the multi-frequency behavior of the quasar 3C 454.3 during three prominent gamma -ray outbursts: 2009 Autumn, 2010 Spring, and 2010 Autumn. The data reveal a repeating pattern, including a ...triple flare structure, in the properties of each gamma -ray outburst, which implies similar mechanism(s) and location for all three events. The multi-frequency behavior indicates that the lower frequency events are co-spatial with the gamma -ray outbursts, although the gamma -ray emission varies on the shortest timescales. We determine that the variability from UV to IR wavelengths during an outburst results from a single synchrotron component whose properties do not change significantly over the different outbursts. Despite a general increase in the degree of optical linear polarization during an outburst, the polarization drops significantly at the peak of the gamma -ray event, which suggests that both shocks and turbulent processes are involved. We detect two disturbances (knots) with superluminal apparent speeds in the parsec-scale jet associated with the outbursts in 2009 Autumn and 2010 Autumn. The kinematic properties of the knots can explain the difference in amplitudes of the gamma -ray events, while their millimeter-wave polarization is related to the optical polarization during the outbursts. We interpret the multi-frequency behavior within models involving either a system of standing conical shocks or magnetic reconnection events located in the parsec-scale millimeter-wave core of the jet. We argue that gamma -ray outbursts with variability timescales as short as ~3 hr can occur on parsec scales if flares take place in localized regions such as turbulent cells.
We have been performing multi-wavelength monitoring of a sample of γ -ray blazars since the launch of the Fermi Gamma-ray Space Telescope in 2008. We present γ -ray and optical light curves for ...several quasars and BL Lac objects from the sample to illustrate different patterns of variability. We investigate correlations between γ -ray and R-band light curves and, if these are statistically significant, determine delays between variations at the two wavebands. Such time delays can reveal the relative locations of the emitting regions in AGN jets and the origin of the high-energy photons. We present preliminary results of this analysis. Of the 29 blazars with sufficient time coverage, 17 display a significant, singular, correlated time lag when tested over the entire 7-year period. Of these sources, the six that exhibit a consistent time lag across a majority of epochs of high activity have lags of 0 ± 7 days; the 11 without consistency across epochs of high activity generally display longer mean lags, with γ -ray leading optical. Eleven sources display no significant singular correlation over either the entire 7-year period or across shorter intervals. No significant difference is apparent between the BL Lac objects and FSRQs. Even after 7 years of monitoring, our correlation analysis remains plagued with uncertainties due to insufficient data.
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•Ironstones were smelted for bloomery iron in the middle Trans-Urals in the past.•Itkul culture metallurgists performed small-scale iron-working during the Iron Age.•Talc-tempered ...clays were used for the production of various metallurgical ceramics.•The EIA ironworking slags possibly source to Fe ores that co-occur with Cu deposits.•Skills of Cu metallurgy possibly promoted the early trials with Fe metallurgy.
In the mountain-forest zone of the middle Trans-Urals, iron technology is conventionally thought to have been adopted during the local early Iron Age (EIA, 7th-3rd c. BCE) by the skilled bronze-working population of the Itkul culture. However, these claims remain unresolved at present, as most of excavations of Itkul sites were carried out during 1960–1980′ s, and some Itkul sites featuring iron production remains also contain evidence of medieval (6th-10th/16th c. AD) occupation. We analyse via SEM-EDS iron-metallurgical slags, iron ores, technical ceramics, iron object and copper slags from one of the key clusters of Itkul sites, Irtyash Lake, in order to provide first insight into past metal production practices, exploited ore sources and the possible link between copper and iron metallurgy in this part of the Urals. The results confirm bloomery smelting of local ironstone ores in Irtyash area, at least during the medieval period. Beyond that, the analyses provide the first evidence for small-scale iron-smithing at the EIA sites of Irtyash-1 and Shatanov-5, alongside secondary copper-working activities. The compositional similarity observed between iron- and copper-working slags from Irtyash-1 indicates the deliberate use of talc-tempered clay mixtures for iron and copper-metallurgical ceramics, which is likely related to their refractory properties. The iron-working slags from the EIA sites suggest the use of iron ores associated with copper deposits, although primary slags formed during the smelting of these iron ores were not identified. It is possible that the early trials iron metallurgy in the middle Trans-Urals, during the EIA, were stimulated by the rich experience of the Itkul population with copper metallurgy and their deep knowledge of the diverse mineral resource base of the Urals.
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•Andradite relicts in slags indicate provenance to the major skarn-hosted deposit.•Oxidic copper ores were smelted under moderate redox conditions.•Heterogeneous ...pyroxene-magnetite-glassy plate slags are common by-products.•Copper production was oriented at both domestic and external markets.•Metallurgists were likely divided into smelters and copper-workers.
During the EIA (7th-3rd c. BCE), the middle Trans-Urals were populated by the Itkul culture of metalworkers. Most of the Itkul sites were excavated in 1960-1980′s, and ever since then the copper smelting technology, and exploited ore sources remained limitedly understood. To provide insight into these questions, we consider the archaeological context of copper production and apply methods of OM, SEM-EDS and LA ICP-MS to analyse copper slag, technical ceramics and ores from the Itkul culture settlement of Dautovo-1 (Itkul-1). This data is considered against the analyses of ores from the EIA sites and the Gumeshevsky mine in the Polevskoy area located 35 km from Dautovo, and the formerly investigated copper slags (Stepanov et al., 2021) from the site of Irtyash-1 located 50 km apart. The obtained results confirm that secondary copper ores of the Gumeshevsky mine, long regarded as the main ore source of the Itkul culture, were smelted at the site of Dautovo-1. We also identify the plate slag as the residue attesting to the most frequently used smelting technique, which consisted of the smelting of secondary copper ores in shallow open furnaces or crucibles and under moderately reducing conditions. The smelt ended with the removal and fast-cooling of slag outside the furnace. In contrast to Dautovo-1, only slags from secondary metallurgical operations were found at the site of Irtyash-1, which aligns with the dominance of secondary copper-working remains at the latter site. The production probably was likely performed on a seasonal basis, the metalworking society was divided into smelters and copper-workers, and the copper supply was likely oriented at both domestic and external (nomadic) markets.
Aim: to perform a comparative analysis of the clinical efficacy of 2.5% phenylephrine with and without hypromellose for the treatment of extra accommodation strain in schoolchildren with myopia and ...to perform an experimental evaluation of the pharmacological effective of active ingredient of the finished dosage form (FDF) of preparations containing 2.5% phenylephrine with and without excipients. Patients and Methods: this clinical study enrolled 122 schoolchildren, 11–17 years old, with extra accommodation strain of various severity. The children were split into two groups. The group 1 patients received Irifrin® BK, containing 2.5% phenylephrine with hypromellose, one eye drop at the bedtime during 30 days, and the group 2 patients — Preparation A (2.5% phenylephrine without hypromellose) according to the same dosage regimen. The accommodative function was evaluated using the Speedy-i accommodation analyzer, and the coefficients of accommodation response before and 30 days after the treatment were determined. The experimental study was carried out in 40 sexually mature male rabbits of the Soviet Chinchilla breed to evaluate the development and duration of mydriatic effect and to measure the concentration of active ingredient — phenylephrine with hypromellose, as an excipient (Irifrin® and Irifrin® BK), phenylephrine without hypromellose (Preparation A) and phenylephrine with sodium hyaluronate as an excipient (Preparation B) in the aqueous humor within the eye anterior chamber using high-performance gas-liquid chromatography with tandem mass spectrometric detection. Results: the drug therapy of extra accommodation strain comprising 2.5% phenylephrine hydrochloride solution with hypromellose as an excipient (Irifrin® BK) demonstrated a decrease in severity of extra accommodation strain after 30 days of treatment. At the same time, Preparation B did not demonstrate its efficacy. In the experimental study, Irifrin® and Irifrin® BK were superior to Preparations A and B (without hypromellose as an excipient) as regards the peak mydriatic effect and the time required to reach maximal mydriasis. The peak phenylephrine concentrations in the aqueous humor within the eye anterior chamber were reached five minutes after instilling 1 drop of 2.5% phenylephrine with hypromellose solutions. These peaks were significantly higher than those observed after instilling Preparations A and B — phenylephrine in the same concentration but without hypromellose. Conclusion: the addition of hypromellose as an excipient to FDF of 2.5% phenylephrine solution helps to optimize pharmacodynamics and pharmacokinetics of the active ingredient by accelerating its inflow in the aqueous humor within the eye anterior chamber, increasing the topical bioavailability, and extending the exposure interval. It is likely that the above factors have underpinned the efficacy of Irifrin® and Irifrin® BK drugs used for the treatment of extra accommodation strain. The same results were obtained in this study comparing the clinical efficacy of 2.5% phenylephrine solution with hypromellose and its preparations without hypromellose used for the treatment of schoolchildren with extra accommodation strain amid myopia, as proven by the significant improvement of the accommodation indices during the treatment. Keywords: extra accommodation strain, mydriatic effect, peak concentration, rabbit, myopia, phenylephrine, hypromellose. For citation: Makhova M.V., Shikh E.V., Strakhov V.V. et al. Clinical and experimental rationale for using phenylephrine with hypromellose for the treatment of extra accommodation strain in patients with myopia. Russian Journal of Clinical Ophthalmology. 2023;23(1):33–38 (in Russ.). DOI: 10.32364/2311-7729-2023-23-1-33-38
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