Stability of boron-doped graphene/copper interface: DFT, XPS and OSEE studies

Two different types of boron-doped graphene/copper interfaces synthesized using two different flow rates of Ar through the bubbler containing the boron source were studied. X-ray photoelectron spectra (XPS) and optically stimulated electron emission (OSEE) measurements have demonstrated that boron-doped graphene coating provides a high corrosion resistivity of Cu-substrate with the light traces of the oxidation of carbon cover. The density functional theory calculations suggest that for the case of substitutional (graphitic) boron-defect only the oxidation near boron impurity is energetically favorable and creation of the vacancies that can induce the oxidation of copper substrate is energetically unfavorable. In the case of non-graphitic boron defects oxidation of the area, a nearby impurity is metastable that not only prevent oxidation but makes boron-doped graphene. Modeling of oxygen reduction reaction demonstrates high catalytic performance of these materials.Comment: 15 pages, 8 figures, to appear in Appl. Surf. Sc

Calculation of the lidar signal by the DDA method applied to the data of satellite remote sensing of cirrus clouds for climate change detection

The purpose of this work is to solve an important issue: the light scattering problem for ice crystals of cirrus clouds less than 10 μm and matching the obtained solution with the existing solution obtained within the physical optics approximation. The article presents a solution to the problem of light scattering by hexagonal ice particles of cirrus clouds with sizes from 0.05 to 5.17 μm for a wavelength 0.532 μm, obtained within the discrete dipole approximation. It is found that the obtained solution is in good agreement with the physical optics approximation in the vicinity of scattering angles of 0–10є (the vicinity of forward direction scattering). However, to solve the problem of light scattering in the vicinity of the backward scattering direction, which is important for the interpretation of lidar data, it is necessary to continue the calculations to sizes of the order of 20 μm. The results obtained are necessary for constructing algorithms for the interpretation of lidar data obtained by sounding cirrus clouds

FEATURES OF EXOELECTRON EMISSION IN ALN SINGLE CRYSTALS

The processes of photo- (PSEE) and thermally stimulated exoelectron emission (TSEE) in bulk AlN single crystals were preliminary investigated. It was shown that there is a monotonic growth of PSEE current under photostimulation energy > 4.75 eV. It was observed that TSEE peaks in electrons irradiated sample shifted to the low temperature region by 30 K as compared to the irradiation by photons. The electron origin of shallow traps active in AlN single crystals was manifested.Работа выполнена при поддержке стипендии Президента РФ (СП-3437.2015.1)

An eco-friendly approach to enhance the extraction and recovery efficiency of isoflavones from kudzu roots and soy molasses wastes using ultrasound-assisted extraction with natural deep eutectic solvents (NADES)

The extraction efficiency, recovery, quantification, and stability of isoflavones (daidzein, genistein and puerarin) from the wastes /by-products of kudzu roots and soy molasses were evaluated by using natural deep eutectic solvents (NADESs) coupled with ultrasound-assisted extraction. The NADES extraction was compared with the conventional Soxhlet extraction technique, and the extracted isoflavones were quantified using HPLC-UV/Vis. Results showed extractability of puerarin to be significantly increased (p < 0.0001) in proportion to the increased water concentration of NADES (9.7 ± 0.2, 12.6 ± 0.2, and 14.8 ± 0.3 mg/g in NADESs containing 10%, 20%, and 30% water, respectively). Despite having less isoflavone content, kudzu roots and soy molasses extracts obtained using NADES exhibited higher antioxidant activity when compared with methanolic extracts. Further, NADES extracts also markedly reduced the degradation degree of isoflavones. The results of this investigation support the use of green extraction techniques to obtain value-added components like isoflavones from wastes/by-products like that of kudzu roots and soy molasses, which are envisaged to find future potential applications in the food and pharmaceutical industries. © 2022 Elsevier B.V.Russian Science Foundation, RSF: 20–66-47017This work was supported by the Russian Science Foundation RSF (Grant agreement number 20–66-47017 ).The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Elena G. Kovaleva reports financial support was provided by Russian Science Foundation RSF (Grant agreement number 20–66–47017)

Terbium photo-, cathodo- and X-ray luminescence in sol-gel derived films in porous anodic alumina

Photo-, cathodo-, and X-ray luminescence of terbium in sol-gel derived films, fabricated in porous anodic alumina is studied. The cell size of the fabricated film convertor of irradiation is about 250 nm. The methods of increase Tb luminescence under diverse excitation conditions are discussed. © 2012 CriMiCo

ОСОБЕННОСТИ АЗОТНОГО ПИТАНИЯ ЯРОВОЙ ПШЕНИЦЫ ПРИ МИНИМИЗАЦИИ ОСНОВНОЙ ОБРАБОТКИ ЧЕРНОЗЕМА ВЫЩЕЛОЧЕННОГО НОВОСИБИРСКОГО ПРИОБЬЯ

The paper aims to study the characteristics of spring wheat nitrogen nutrition in crop rotation in the field under minimum primary soil tillage. The research was carried out in the multifactor stationary field experiment in 2002–2013. The work examined the seasonal dynamics of soil nitrate nitrogen and its withdrawal incorporated in agrophytocenose in 4 variants of soil tillage systems in the fields of grain fallow rotation in the extensive background, it also studied spring wheat productivity in extensive and intensive backgrounds. It was established that under the conditions of West Siberia forest-steppe and in its black soils leached by bare black fallow with tillage, the amount of mineral nitrogen went up 2.5 and 2 times as much as the initial value over the fallow period and bare early minimum fallow period, respectively. In the spring prior to wheat sowing in the fallow, nitrogen content in a 1-meter soil layer constituted 159 kg/ha when sown in the tillage, which is 1.2 and 1.3 times as much as sown in the minimum fallow and “zero” tillage, respectively. Wheat yielding when grown in the fallow in extensive and intensive backgrounds made up 2.66–2.83 and 3.53–3.61 t/ha, respectively, and in fact, did not depend upon the techniques of the fallow preparation. In the repeated sowings, wheat productivity was 1.1–1.3 times higher in the extensive background in the tillage (1.29–1.66 t/ha) than that in the minimum tillage. With optimized mineral nutrition in plants and phytosanitary situation in seedings the productivity of wheat in field crop rotations went up 2.1–2.8 times as much without any considerable differences in soil tillage variants. Agrophytocenose fallowed was characterized by the highest indexes (125.0–130.3 kg/ha) for nitrate nitrogen withdrawn from the soil somewhat lowering from tillage to minimum cultivations. Herewith, the withdrawal of the element concerned from the soil with weeds in the extensive background built up from 8.6 kg/ha in the black fallow to 14.0 kg/ha for the early minimal fallow, for grain predecessors it went up from 15.7 in the tillage to 26.9 kg/ha in “zero’ tillage.Цель настоящей работы – изучение особенностей азотного питания яровой пшеницы в  полевом севообороте при минимизации основной обработки почвы. Исследования проводили в многофакторном стационарном полевом опыте в 2002–2013 гг. Изучали сезонную динамику со- держания нитратного азота в почве и вынос его с агрофитоценозом в четырех вариантах систем обработки почвы в  полях зернопарового севооборота на экстенсивном фоне, а  продуктивность яровой пшеницы  – на экстенсивном и  интенсивном фонах. Установлено, что в  условиях лесостепи Западной Сибири на чернозёмах выщелоченных в чистом черном пару со вспашкой общее количество минерального азота за период парования возросло в 2,5 раза, в чистом раннем минимальном пару – в 2 раза в сравнении с исходным значением. Весной перед посевом пшеницы по пару содержание азота в метровом слое почвы составило 159 кг/га по вспашке, что в 1,2 раза больше, чем по минимальной, и в 1,3 раза в сравнении с «нулевой» обработкой. Урожайность пшеницы по пару на экстенсивном и интенсивном фонах составила 2,66–2,83 и 3,53–3,61 т/га соответственно и практически не зависела от способов его подготовки. На повторных посевах урожайность пшеницы на экстенсивном фоне по вспашке (1,29–1,66 т/га) была в  1,1–1,3 раза больше, чем по минимальным обработкам. При оптимизации минерального питания растений и фитосанитарной ситуации посевов продуктивность пшеницы в полях севооборота увеличивалась в 2,1–2,8 раза без существенных различий по вариантам обработки почвы. Агрофитоценоз, идущий по пару, характеризовался наибольшими показателями (125,0–130,3  кг/га) по выносу нитратного азота из почвы, несколько снижаясь от вспашки к минимальным обработкам. При этом вынос данного элемента из почвы с сорняками на экстенсивном фоне нарастал от 8,6 кг/га по черному пару со вспашкой до 14,0 кг/га по раннему минимальному пару, по зерновым предшественникам – от 15,7 по вспашке до 26,9 кг/га по «нулевой» обработке

Genome Sequence of a Mesophilic Hydrogenotrophic Methanogen Methanocella paludicola, the First Cultivated Representative of the Order Methanocellales

We report complete genome sequence of a mesophilic hydrogenotrophic methanogen Methanocella paludicola, the first cultured representative of the order Methanocellales once recognized as an uncultured key archaeal group for methane emission in rice fields. The genome sequence of M. paludicola consists of a single circular chromosome of 2,957,635 bp containing 3004 protein-coding sequences (CDS). Genes for most of the functions known in the methanogenic archaea were identified, e.g. a full complement of hydrogenases and methanogenesis enzymes. The mixotrophic growth of M. paludicola was clarified by the genomic characterization and re-examined by the subsequent growth experiments. Comparative genome analysis with the previously reported genome sequence of RC-IMRE50, which was metagenomically reconstructed, demonstrated that about 70% of M. paludicola CDSs were genetically related with RC-IMRE50 CDSs. These CDSs included the genes involved in hydrogenotrophic methane production, incomplete TCA cycle, assimilatory sulfate reduction and so on. However, the genetic components for the carbon and nitrogen fixation and antioxidant system were different between the two Methanocellales genomes. The difference is likely associated with the physiological variability between M. paludicola and RC-IMRE50, further suggesting the genomic and physiological diversity of the Methanocellales methanogens. Comparative genome analysis among the previously determined methanogen genomes points to the genome-wide relatedness of the Methanocellales methanogens to the orders Methanosarcinales and Methanomicrobiales methanogens in terms of the genetic repertoire. Meanwhile, the unique evolutionary history of the Methanocellales methanogens is also traced in an aspect by the comparative genome analysis among the methanogens

Methanosarcina acetivorans C2A Topoisomerase IIIα, an Archaeal Enzyme with Promiscuity in Divalent Cation Dependence

Topoisomerases play a fundamental role in genome stability, DNA replication and repair. As a result, topoisomerases have served as therapeutic targets of interest in Eukarya and Bacteria, two of the three domains of life. Since members of Archaea, the third domain of life, have not been implicated in any diseased state to-date, there is a paucity of data on archaeal topoisomerases. Here we report Methanosarcina acetivorans TopoIIIα (MacTopoIIIα) as the first biochemically characterized mesophilic archaeal topoisomerase. Maximal activity for MacTopoIIIα was elicited at 30–35°C and 100 mM NaCl. As little as 10 fmol of the enzyme initiated DNA relaxation, and NaCl concentrations above 250 mM inhibited this activity. The present study also provides the first evidence that a type IA Topoisomerase has activity in the presence of all divalent cations tested (Mg2+, Ca2+, Sr2+, Ba2+, Mn2+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+ and Cd2+). Activity profiles were, however, specific to each metal. Known type I (ssDNA and camptothecin) and type II (etoposide, novobiocin and nalidixic acid) inhibitors with different mechanisms of action were used to demonstrate that MacTopoIIIα is a type IA topoisomerase. Alignment of MacTopoIIIα with characterized topoisomerases identified Y317 as the putative catalytic residue, and a Y317F mutation ablated DNA relaxation activity, demonstrating that Y317 is essential for catalysis. As the role of Domain V (C-terminal domain) is unclear, MacTopoIIIα was aligned with the canonical E. coli TopoI 67 kDa fragment in order to construct an N-terminal (1–586) and a C-terminal (587–752) fragment for analysis. Activity could neither be elicited from the fragments individually nor reconstituted from a mixture of the fragments, suggesting that native folding is impaired when the two fragments are expressed separately. Evidence that each of the split domains plays a role in Zn2+ binding of the enzyme is also provided