Iron metallurgy of the Xianbei period in Tuva (Southern Siberia)

We present results of the complex investigation of large-scale iron production at the site of Katylyg 5 (Tuva, Southern Siberia) dating to 3rd-4th c. AD. The excavations have uncovered nine trapezoid underground smelting furnaces, a tonne of smelting slag, smithing remains and a charcoal production zone. The investigation of slag by Optical microscopy, SEM-EDS and ICP-MS confirms the performance of smelting and smithing operations at the site, and also suggests that the smelted ore was magnetite, associated with quartz. The presence of copper (bronze) prills in most of the smithing slag indicates that copper was worked alongside iron in the smithing hearths. The spatial division of the site into three different production zones (smelting, smithing and charcoalproduction) suggests a well-organized and self-sufficient industry, that was probably tightly controlled throughout all stages of the chaîne op´eratoire. The trapezoid furnaces identified at Katylyg, are also known from Cis-Baikal region where they date from the end of the 1st millennium BCE and throughout most of the 1st millennium AD. This suggests that the technology of trapezoid furnaces, along with the Kokel culture to which they are attributed, likely emerged in Tuva with the migrations from the Baikal region due to the westward Xianbei expansion during 1st-3rd c. AD

Coal-Derived Humic Substances: Insight into Chemical Structure Parameters and Biomedical Properties

An investigation was carried out on humic substances (HSs) isolated from the coal of the Kansk-Achinsk basin (Krasnoyarsk Territory, Russia). The coal HSs demonstrate the main parameters of molecular structure inherent to this class of natural compounds. An assessment was performed for the chemical, microbiological, and pharmacological safety parameters, as well as the biological efficacy. The HS sample meets the safety requirements in microbiological purity, toxic metals content (lead, cadmium, mercury, arsenic), and radionuclides. The presence of 11 essential elements was determined. The absence of general, systemic toxicity, cytotoxicity, and allergenic properties was demonstrated. The coal HS sample was classified as a Class V hazard (low danger substances). High antioxidant and antiradical activities and immunotropic and cytoprotective properties were identified. The ability of the HS to inhibit hydroxyl radicals and superoxide anion radicals was revealed. Pronounced actoprotective and nootropic activities were also demonstrated in vivo. Intragastric administration of the HS sample resulted in the improvement of physical parameters in mice as assessed by the “swim exhaustion” test. Furthermore, intragastric administration in mice with cholinergic dysfunction led to a higher ability of animals with scopolamine-induced amnesia to form conditioned reflexes. These findings suggest that the studied HS sample is a safe and effective natural substance, making it suitable for use as a dietary bioactive supplement