Features of frictional treatment of the composite NiCrBSi-Cr3 C2 laser clad coating

The authors conducted a comparative analysis of the effectiveness of frictional treatment with a sliding indenter of a NiCrBSi coating and a composite coating formed by laser cladding of a powder mixture of 85 wt.% NiCrBSi and 15 wt.% Cr3 C2 . The criteria were intensive strain hardening, favorable compressive stresses, and low surface roughness. Frictional treatment with an indenter made of cubic boron nitride at a load of 350 N provides less intense deformational hardening of the NiCrBSi-Cr3 C2 coating (microhardness growth from 900 to 940 HV 0.025) than the NiCrBSi coating (from 570 to 850 HV 0.025). This is due to the significantly higher initial hardness of the composite coating, because its structure, in addition to the phases characteristic of the NiCrBSi coating, contains large primary Cr3 C2 carbides, which did not dissolve during cladding, as well as elongated Cr23 C6 carbides, precipitated during cooling from a solid solution supersaturated with chromium as a result of the partial dissolution of Cr3 C2 carbides during cladding. Frictional treatment also results in a lower level of compressive residual stresses (−250 MPa) on the composite coating surface than on the NiCrBSi coating surface (−390 MPa). In contrast to frictional treatment of the NiCrBSi coating, when a smoothed surface with a nano-roughness is formed (Ra = 60 nm), frictional treatment of the composite coating forms a surface with a higher roughness (Ra = 310 nm) due to the creation on the surface of supporting “island frame” of large Cr3 C2 chromium carbides protruding 2 – 5 μm. © 2020, Institute for Metals Superplasticity Problems of Russian Academy of Sciences. All rights reserved.The work was performed with the financial support of the Grant from the President of the Russian Federation for young scientists MK-391.2019.8 and at the expense of funds making up the income from the trust management of the target capital for the development of UrFU, formed with the participation of UMMC-Holding Corp, as well as within the state order for IES UB RAS (AAAA-A18-118020790147-4) and IMP UB RAS (AAAA-A18-118020190116-6 and АААА-А19-119070490049-8). The experimental research was performed on the equipment of the Plastometriya Collective Use Center of IES UB RAS

Evidence of the Generation of Isosaccharinic Acids and Their Subsequent Degradation by Local Microbial Consortia within Hyper-Alkaline Contaminated Soils, with Relevance to Intermediate Level Radioactive Waste Disposal

The contamination of surface environments with hydroxide rich wastes leads to the formation of high pH (>11.0) soil profiles. One such site is a legacy lime works at Harpur Hill, Derbyshire where soil profile indicated in-situ pH values up to pH 12. Soil and porewater profiles around the site indicated clear evidence of the presence of the α and β stereoisomers of isosaccharinic acid (ISA) resulting from the anoxic, alkaline degradation of cellulosic material. ISAs are of particular interest with regards to the disposal of cellulosic materials contained within the intermediate level waste (ILW) inventory of the United Kingdom, where they may influence radionuclide mobility via complexation events occurring within a geological disposal facility (GDF) concept. The mixing of uncontaminated soils with the alkaline leachate of the site resulted in ISA generation, where the rate of generation in-situ is likely to be dependent upon the prevailing temperature of the soil. Microbial consortia present in the uncontaminated soil were capable of surviving conditions imposed by the alkaline leachate and demonstrated the ability to utilise ISAs as a carbon source. Leachate-contaminated soil was sub-cultured in a cellulose degradation product driven microcosm operating at pH 11, the consortia present were capable of the degradation of ISAs and the generation of methane from the resultant H2/CO2 produced from fermentation processes. Following microbial community analysis, fermentation processes appear to be predominated by Clostridia from the genus Alkaliphilus sp, with methanogenesis being attributed to Methanobacterium and Methanomassiliicoccus sp. The study is the first to identify the generation of ISA within an anthropogenic environment and advocates the notion that microbial activity within an ILW-GDF is likely to influence the impact of ISAs upon radionuclide migration

Desulfuribacillus alkaliarsenatis gen. nov. sp. nov., a deep-lineage, obligately anaerobic, dissimilatory sulfur and arsenate-reducing, haloalkaliphilic representative of the order Bacillales from soda lakes

An anaerobic enrichment culture inoculated with a sample of sediments from soda lakes of the Kulunda Steppe with elemental sulfur as electron acceptor and formate as electron donor at pH 10 and moderate salinity inoculated with sediments from soda lakes in Kulunda Steppe (Altai, Russia) resulted in the domination of a Gram-positive, spore-forming bacterium strain AHT28. The isolate is an obligate anaerobe capable of respiratory growth using elemental sulfur, thiosulfate (incomplete reduction) and arsenate as electron acceptor with H2, formate, pyruvate and lactate as electron donor. Growth was possible within a pH range from 9 to 10.5 (optimum at pH 10) and a salt concentration at pH 10 from 0.2 to 2 M total Na+ (optimum at 0.6 M). According to the phylogenetic analysis, strain AHT28 represents a deep independent lineage within the order Bacillales with a maximum of 90 % 16S rRNA gene similarity to its closest cultured representatives. On the basis of its distinct phenotype and phylogeny, the novel haloalkaliphilic anaerobe is suggested as a new genus and species, Desulfuribacillus alkaliarsenatis (type strain AHT28T = DSM24608T = UNIQEM U855T)

Microbial diversity and biogeochemical cycling in soda lakes

Soda lakes contain high concentrations of sodium carbonates resulting in a stable elevated pH, which provide a unique habitat to a rich diversity of haloalkaliphilic bacteria and archaea. Both cultivation-dependent and -independent methods have aided the identification of key processes and genes in the microbially mediated carbon, nitrogen, and sulfur biogeochemical cycles in soda lakes. In order to survive in this extreme environment, haloalkaliphiles have developed various bioenergetic and structural adaptations to maintain pH homeostasis and intracellular osmotic pressure. The cultivation of a handful of strains has led to the isolation of a number of extremozymes, which allow the cell to perform enzymatic reactions at these extreme conditions. These enzymes potentially contribute to biotechnological applications. In addition, microbial species active in the sulfur cycle can be used for sulfur remediation purposes. Future research should combine both innovative culture methods and state-of-the-art ‘meta-omic’ techniques to gain a comprehensive understanding of the microbes that flourish in these extreme environments and the processes they mediate. Coupling the biogeochemical C, N, and S cycles and identifying where each process takes place on a spatial and temporal scale could unravel the interspecies relationships and thereby reveal more about the ecosystem dynamics of these enigmatic extreme environments

Natronogracilivirga saccharolytica gen. nov., sp. nov. and Cyclonatronum proteinivorum gen. nov., sp. nov., haloalkaliphilic organotrophic bacteroidetes from hypersaline soda lakes forming a new family Cyclonatronaceae fam. nov. in the order Balneolales

Two heterotrophic bacteroidetes strains were isolated as satellites from autotrophic enrichments inoculated with samples from hypersaline soda lakes in southwestern Siberia. Strain Z-1702 T is an obligate anaerobic fermentative saccharolytic bacterium from an iron-reducing enrichment culture, while Ca. Cyclonatronum proteinivorum Omega T is an obligate aerobic proteolytic microorganism from a cyanobacterial enrichment. Cells of isolated bacteria are characterized by highly variable morphology. Both strains are chloride-independent moderate salt-tolerant obligate alkaliphiles and mesophiles. Strain Z-1702 T ferments glucose, maltose, fructose, mannose, sorbose, galactose, cellobiose, N-acetyl-glucosamine and alpha-glucans, including starch, glycogen, dextrin, and pullulan. Strain Omega T is strictly proteolytic utilizing a range of proteins and peptones. The main polar lipid fatty acid in both strains is iso-C 15:0, while other major components are various C 16 and C 17 isomers. According to pairwise sequence alignments using BLAST Gracilimonas was the nearest cultured relative to both strains (<90% of 16S rRNA gene sequence identity). Phylogenetic analysis placed strain Z-1702 T and strain Omega T as two different genera in a deep-branching clade of the new family level within the order Balneolales with genus. Based on physiological characteristics and phylogenetic position of strain Z-1702 T it was proposed to represent a novel genus and species Natronogracilivirga saccharolityca gen. nov., sp. nov. (= DSMZ 109061 T =JCM 32930 T =VKM B 3262 T). Furthermore, phylogenetic and phenotypic parameters of N. saccharolityca and C. proteinivorum gen. nov., sp. nov., strain Omega T (=JCM 31662 T, =UNIQEM U979 T), make it possible to include them into a new family with a proposed designation Cyclonatronaceae fam. nov. Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.BT/Environmental Biotechnolog

New Representatives of the Class <i>Ignavibacteria</i> Inhabiting Subsurface Aquifers of Yessentuki Mineral Water Deposit

The Yessentuki mineral water deposit (YMWD) is a well-known source of balneologically valuable drinking mineral water, but it has rarely been investigated in terms of the microbes inhabiting it. In this work, we have studied the microbial communities of the continuously operating production well 9, penetrating the Lower Cretaceous aquifer of the YMWD, and characterized, in detail, two novel representatives of class Ignavibacteria (Bacteroidota). One representative of the so-called XYB12-FULL-38-5 group within the family Melioribacteraceae has been isolated in pure culture, designated strain 09-Me, and physiologically characterized. It is a facultatively anaerobic thermotolerant microorganism capable of fermentation and respiration on simple and complex sugars (lichenan, xanthan gum, glucomannan, curdlan, pachyman). In addition to oxygen, ferric iron, arsenate, and elemental sulfur were also used as electron acceptors. Phylogenomic and physiological analyses reveal this novel isolate to represent a novel genus and species for which the name Stygiobacter electus gen. nov., sp. nov. is proposed. The second representative of the family Melioribacteraceae described here belonged to the so-called DSXH01 group, which comprises the dominant group (up to 28%) of the microbial community of well 9 water. The organism was characterized through the analysis of its genome, assembled from metagenome of well 9 (Ess09-04 MAG). Genes encoding enzymes of carbohydrate utilization and genes responsible for aerobic and anaerobic respiration have been identified in the genomes of both bacteria. The investigation of the environmental distribution of Stygiobacter genus-related bacteria and representatives of the lineage DSXH01 has shown that they all are typical inhabitants of the subsurface biosphere, and are often found in bioreactors. These data significantly expand our knowledge on the microbes of subsurface water basins and pave the way for future studies of the novel members of Ignavibacteria class

2001: Melatonin increases both life span and tumor incidence in female CBA mice. The Journals of Gerontology

From the age of 6 months until their natural deaths, female CBA mice were given melatonin with their drinking water (20 mg/l) for 5 consecutive days every month. Intact mice served as controls. The results of this study show that the consumption of melatonin did not significantly influence food consumption, but it did increase the body weight of older mice; it did not influence physical strength or the presence of fatigue; it decreased locomotor activity and body temperature; it inhibited free radical processes in serum, brain, and liver; it slowed down the agerelated switching-off of estrous function; and it increased life span. However, we also found that treatment with the used dose of melatonin increased spontaneous tumor incidence in mice. For this reason, we concluded that it would be premature to recommend melatonin as a geroprotector for long-term use

Novel Extracellular Electron Transfer Channels in a Gram-Positive Thermophilic Bacterium

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