The analgesic and anti-inflammatory properties of trisand tetrakis-derivatives of pyridoxine and ketorolac were examined using mechanical and chemical irritation tests and acute inflammation model. In the carrageenan-induced paw edema, acetic acid-induced writhing, and cute exudative inflammation models, the compounds provided analgesic efficacy comparable to that of ketorolac tromethamine, the most potent non-opioid analgesic, but with a longer duration of action and reduced toxicity after 14 days of daily intragastric administration.

The radioprotective properties of a human placenta hydrolysate known commercially as Laennec (Japan Bio Products, Co. Ltd., Japan) were studied. The preparation was administered intraperitoneally to male ICR (CD-1) mice using two regimens. In the first scenario, the mice received 112 μg/g of the preparation at 30 min and one, two, and three days after irradiation. Alternatively, they were given five daily injections of the preparation at a dosage of 112 μg/g and exposed to 6.5 Gy irradiation on the third day after the final administration. The efficacy of the preparation was assessed by 30-day survival rate, as well as by biological indices obtained four days after irradiation (number of nucleated cells in bone marrow, content of thiobarbituric acid reactive substances (TBARS) in liver, and leukocyte and platelet levels in blood). Neither of the two regimens improved survival or alleviated pancytopenia in the irradiated mice. However, the reduced TBARS contents in liver suggest that the preparation may exert a slight inhibitory effect on the metabolism of lipid radiotoxins.

This article provides an overview of the recent literature on diatom microalgae in order to assess their potential as producers of biologically valuable substances such as fucoxanthin and polyunsaturated fatty acids (PUFAs). The biochemical, physiological, and genetic features of diatom algae that make them suitable for use in biotechnological production were summarized. The general properties of fucoxanthin and PUFAs were outlined, as well as their therapeutic and prophylactic benefits that create a steady demand for these critical bioresources. Fucoxanthin and PUFAs content and productivity in different microalgae species were analyzed. Phaeodactylum tricornutum, a promising candidate for commercial production of fucoxanthin and fatty acids, was described, with a focus on its general biology, current methods of cultivation, and prospects for genetic modification. The influence of cultivation conditions on the accumulation of fucoxanthin and PUFAs in P. tricornutum was examined, along with some aspects of its biomass processing, including harvesting and extraction of biologically valuable substances. The possibilities for complex biomass processing to improve the efficiency of biotechnological production were investigated.

Rare plant communities with the participation of Thymus dubjansky, an endemic of the Middle Volga region, were studied on the chalk slopes in the Samara region. Using the approach of J. Braun-Blanquet, a total of 30 relevés were processed with the JUICE software. The primary classification by the TWINSPAN algorithm revealed two distinctive communities. The DCA ordination was performed, and reliable correlations were found between the position of the phytocenoses and L.G. Ramensky’s environmental indicators. The identified communities differed in terms of their environmental indicators and exhibited floristic heterogeneity. They were represented by typical steppe taxa and calciphilous species, 30 % of which were rare. For the first time, two new associations were established in the сalciphilous vegetation of the Samara Pre-Volga region: Artemisio salsoloidis-Thymetum dubjanskyi ass. nov. hoc loco and Gypsophilо volgensis-Thymetum dubjanskyi ass. nov. hoc loco. Due to their narrow distribution range, the communities with Thymus dubjansky were classified only provisionally. The сalciphilous subshrub communities of the established associations correspond to the initial stages of overgrowth on the slopes and elevations of chalk massifs in the Samara region. Given the vulnerability of their substrate to natural and anthropogenic degradation, the phytocenoses with Thymus dubjansky should be considered rare.

Pollution with heavy metals has become a major concern in food security. Their accumulation levels in different plants are strongly influenced by weather conditions. In this study, several series of experiments were carried out to assess the individual and combined effects of two stress factors (moisture deficit and heavy metal pollution) on morphometric parameters, physiology, and antioxidant status of sunflower plants. Drought stress significantly reduced shoot length, promoted root elongation, and caused alterations in cotyledon shape. The highest concentrations of malondialdehyde (MDA), a known marker of oxidative stress, were found in the plants under drought alone and in combination with heavy metal stress. Individual stresses led to a suppression of the low-molecular-weight antioxidant system in the plants, while combined stresses activated it as a primary defense mechanism, coinciding with the decreased contents of photosynthetic pigments. Aridification (drought) intensified cadmium accumulation in the plants without any visible changes in the morphology of their aboveground biomass, but with the stimulation of root system growth through an increase in the number of lateral roots. Among the tested heavy metals, lead was the most toxic when applied individually, resulting in a linear decrease in the contents of photosynthetic pigments as its concentration in the substrate increased.

This article describes the results of a study on DDT content in the watercourses of the Volga River delta. Based on the data from the long-term state environmental monitoring in 1985–2022, DDT concentrations in the water of the investigated region were determined, as well as the main sources and levels of DDT pollution. The associated environmental risks were assessed. All data were processed using standard statistical methods. For each period, a range of DDT concentrations was established, with significant spatial and temporal variations. It was demonstrated that, on average, DDT concentrations in recent decades have remained in compliance with general environmental quality standards. The areas with the highest levels of DDT pollution were identified. The transit runoff was found to be the primary source of DDT pollution. The environmental risk analysis revealed that the impact of DDT pollution in the Volga River delta is of no concern, but systematic monitoring is needed to manage it effectively.

A model field experiment was carried out over two consecutive growing seasons (2022 and 2023) in the tilled areas with low, medium, and high levels of soil organic matter (SOM) (experimental sites) and adjacent fallows (control sites) to evaluate the potential for predicting CO₂ emissions from humus parameters of the old-arable horizon of fallow light gray forest soil. The CO₂ emissions from the experimental sites exceeded those from the fallows by 3.2–3.4 times in the first year and by 2.6–3.3 times in the second year. The mean differences in CO₂ emissions between the experimental and control sites were 0.175, 0.214, and 0.225 g С-СО /(m²×h) in case of low, medium, and high SOM levels, respectively. The content of Na₄P₂O₇ –NaOH-soluble carbon (Calk) decreased significantly at the sites with medium and high SOM levels, while the decline in total carbon (Ctot) was not significant, and boiling-water-soluble carbon (Cbw) increased. Among the studied parameters, Calk showed the greatest potential as an indicator of humus state in fallow soils for predictive modeling of CO₂ emissions during land use change.

A geoinformation analysis of the retrospective satellite images was performed to reconstruct the spatiotemporal dynamics of changes in the area of the complex desertification sites and the recurrence of desertification processes in the Republic of Kalmykia (excluding arable lands). The recurrence rates were quantified using a layered assessment within a 100-ha regular grid. From the annual assessments of the area of the complex desertification sites (1984–2024), 17 key years were selected, all differing significantly in the overall area affected and the number of desertification hotspots. A total of 67 000 complex desertification sites (spanning over 24 million ha over 17 key years) were identified in order to find intersections, and the recurrence rates of desertification over this period were determined using the grid approach. The desertification sites with zero recurrence accounted for 0.5 % of the territory, while 21.4 % and 47.5 % of the territory had the recurrence of 1–5 and 6–10 times, respectively. The most persistent desertification hotspots with the recurrence of 16–17 times covered 3.6 % of the territory.

For the first time, vivianite mineralization was observed in the West-Biklyanskoye bentonite clay deposit quarry. Vivianite occurred as radiating nodules, secretions, crusts, and earthy aggregates of bright blue color. The host rocks were deluvial loams enriched with syngenetic organic matter originating from the remains of anaerobic microbial colonies. The quarry site with the inclusions of vivianite aggregates was confined to a former bog area, as evidenced by the presence of peat layers in the roof of the sections. In areas where bog deposits were absent, no vivianite mineralization was found along the quarry walls. The formation of vivianite aggregates is therefore associated with the infiltration of bog waters containing mobile forms of iron and phosphorus compounds into the underlying deluvial loams. A continuous input of nutritious organic substances stimulated the proliferation of anaerobic microorganisms within these sediments. Their metabolic activity led to the concentration of mineral phases and the crystallization of vivianite and pyrite grains, which coalesced into aggregates. The change from reducing to oxidizing conditions contributed to the development of limonite crusts composed of goethite and hydrogoethites on top of the vivianite and pyrite aggregates.

This article presents the results of a comparative analysis of paleoclimatic data on the late Paleozoic of the Kuznetsk Basin. Using existing simulations of the Phanerozoic climate, Köppen–Geiger climate types were identified for eight time intervals across the late Paleozoic of the studied territory. The characteristics of the obtained climate types were compared with available paleobotanical, paleozoological, and lithological indicators. Their cenological metrics (taxonomic diversity, dominance, etc.) were examined. On average, the findings agree with established global climate trends of the late Paleozoic – from the humid tropical climate of the early Carboniferous to the more arid conditions of the Permian. Discrepancies between the simulation outcomes and the paleontological evidence were observed mainly in the interpretation of the short-term climatic episodes and local environmental changes.