Relationships between the seasonal dynamics of soil fungi biomass and environmental factors in predominating forest types in the Bryansk woodlands (European Russia)

Being the crucial part of the forest soil's microbial pool, soil fungi in general and mycorrhizal fungi in particular are an important study object when it comes to forest ecosystems sustainability and preservation. Thus, the study of ectomycorrhizal fungi has been carried out in the Bryanskiy Les State Nature Biosphere Reserve, located in the south-eastern part of the Bryansk woodlands (European Russia). Forest types featured in the study are the local predominating types, namely green-moss-fructiculose pine forests and polydominant deciduous broadleaved nemoral-herbaceous forests with spruce. This study was aimed to assess seasonal dynamics of soil fungi' biomass overall and ectomycorrhizal fungi in particular over the course of the 2017 vegetation period (May – November) and its dependence on biotic and abiotic environmental factors, such as soil water content, temperature and vegetation. The vegetation period was divided into three periods of observation, namely an early (May – July), middle (July – September) and late (September – November) one. The method used to assess the fungal biomass was direct microscopic observation using the fluorescein diacetate staining. In order to estimate the ectomycorrhizal fungi biomass separately, trenching and in-growth mesh bags were employed. The obtained results suggest that the soil fungi biomass steadily increases over the vegetation period in both studied forest types. This is mostly affected by the forest type, available water amount and seasonal changes, while the temperature's impact is less pronounced. On average, the soil fungi biomass was higher in broadleaved forests than in pine forests (2.288 mg C × g-1 soil vs. 1.672 mg C × g-1 soil, respectively), with non-ectomycorrhizal component having comparable biomass. The dynamics of biomass differed in the two forest types. However, noticeable differences (p < 0.1) between the two forest types have only been recorded during the July – September period. The biomass of ectomycorrhizal fungi is smaller than the biomass of non-mycorrhizal fungi, but at the same time it is less affected by changes in moisture. Besides that, the study has shown that the forest litter characteristics can greatly affect the dynamics of the fungal biomass

Features of the Application of Friction Braking in High-Speed Track Tests

The increase in the speed characteristics of newly developed aircraft models im-poses new requirements on the test bench equipment of rocket-rail tracks, including braking means. In this paper, the method of friction braking in the conditions of a rocket track is considered. A method for calculating the mode of motion of a rocket sled during friction braking and the thermal wear of the friction elements of braking devices occurring at the same time is presented. An example of the calculation of the friction braking of a conditionally specified rocket sled, per-formed according to the presented method, is shown

Heat Treatment Effect on Magnetic Microstructure of Fe73.9Cu1Nb3Si13.2B8.9 Thin Films

Fe73.9Cu1Nb3Si13.2B8.9 (Finemet) thin films were deposited on the glass substrates by means of radio frequency sputtering. The films thickness was varied from 10 to 200 nm. Heat treatment at temperatures of 350, 400 and 450 °C were performed for 30 minutes in order to control thin film structural state. The X-ray powder diffractometry revealed that the crystallization of α-FeSi nanograins took place only at 450 °C whilst the other samples stayed in the amorphous state. Relation between the structure and magnetic properties of the films was discussed in the framework of random magnetic anisotropy model and the concept of stochastic magnetic domains. The latter was investigated using magnetic force microscopy (MFM). MFM data showed formation of such magnetic domains only in samples thermally treated at 450 °C. There was a tendency of the magnetic domain size reduction with the thickness decrease

Triphenylphosphonium Cations of the Diterpenoid Isosteviol: Synthesis and Antimitotic Activity in a Sea Urchin Embryo Model

A series of novel triphenylphosphonium (TPP) cations of the diterpenoid isosteviol (<b>1</b>, 16-oxo-<i>ent</i>-beyeran-19-oic acid) have been synthesized and evaluated in an in vivo phenotypic sea urchin embryo assay for antimitotic activity. The TPP moiety was applied as a carrier to provide selective accumulation of a connected compound into mitochondria. When applied to fertilized eggs, the targeted isosteviol TPP conjugates induced mitotic arrest with the formation of aberrant multipolar mitotic spindles, whereas both isosteviol and the methyltriphenylphosphonium cation were inactive. The structure–activity relationship study revealed the essential role of the TPP group for the realization of the isosteviol effect, while the chemical structure and the length of the linker only slightly influenced the antimitotic potency. The results obtained using the sea urchin embryo model suggested that TPP conjugates of isosteviol induced mitotic spindle defects and mitotic arrest presumably by affecting mitochondrial DNA. Since targeting mitochondria is considered as an encouraging strategy for cancer therapy, TPP-isosteviol conjugates may represent promising candidates for further design as anticancer agents