Activity of photosystem II in spring barley leaves under the action of manganese ions

The influence of manganese ions (30, 60 and 90 mg/l) on the functioning of the photosystem II (PSII) in leaves was assessed on plants of six spring barley cultivars (Belgorodsky 100, st.). The plants were grown on a complete Knop medium without (control) and with the addition of manganese ions (experiment) under natural light conditions. On 14-day-old leaves, parameters of chlorophyll's rapid fluorescence were recorded using a Fluor Pen FP 110/S fluorometer. The sensitivity of the different structural parts of PSII was found to vary depending on the concentration of Mn ions and the genotype used. Thus, absorbed energy flows increased in the cv. Boyarin at 30 and 60 mg/l Mn (by 7.9 and 14.1 %), in cv. Farmer at 60 and 90 mg/l  (by 15.8 and 16.1 %), but decreased in cv. Dobryak at 30 and 90 mg/l (by 9.7 and 9.0 %), Farmer at 30 mg/l (by 15.8 %) and Bionic at 60 and 90 mg/l (by 8.0 and 6.8 %). The flow of energy stored in primary photochemical reactions in the cv. Bionic increased at 30 mg/l of manganese (by 6.3 %), but decreased at 60 (by 6.8 %) and 90 mg/l (by 5.3 %); increased in the cv. Boyarin at 30 mg/l of Mn (by 6.4 %), but decreased in the cv. Forward (by 11.7 %). Electronic transport leading to CO2 fixation increased in cv. Farmer at all Mn concentrations (by 8.1...12.6 %), and in cv. Bionic it increased at 30 mg/l (by 7.2 %), but decreased at  90 mg/l (by 7.4 %). The electron flux leading to the oxidation of the finile acceptor of PSI in the studied cultivars did not change under the influence of the stressor. However, the integral parameters of PSII activity (PIABS and PIABS_total indices) under stressful conditions were determined by the plant genotype. This indicates, firstly, the need for targeted selection (to a specific level of the stress factor); secondly, on the possibility of pyramidation of the integral level of resistance to the stressor by selecting parents who differ in the level of change in individual functional reactions of photosynthesis

Genotypic variability in the functioning of photosystem II in leaves of covered and naked oats

Background. Comparing the characteristics of primary photosynthetic processes in photosystem II (PSII) in the leaves of two oat (Avena sativa L.) subspecies will help to understand their genetic differentiation. Comparisons between naked and covered oats to assess the efficiency of energy flows within PSII and its relation to useful agronomic traits have not been previously made but can have an effect on their cultivation practices.Materials and methods. Two-week-old plants of 16 covered and 17 naked oat genotypes were assessed for rapid chlorophyll α fluorescence using a Fluor Pen FP 110/S fluorometer. Data on the yield structure were obtained in 2021. The data were processed statistically using descriptive statistics, correlation (Excel 2013) and cluster (StatSoft Statistica 10; Ward's method) analyses.Results. The groups of oat genotypes differed significantly in the absolute magnitude of adsorbed (ABS/RC) and trapped (TRo/RC) light energy flows, which were higher in naked oats (by 7.8 and 7.4%, respectively). The efficiency of electron transfer from plastoquinone QB to PSI in naked oats exceeded that in covered oats by 8.2%. For the whole set of genotypes, a statistically significant correlation of grain yield with the PIABS performance index (r = 0.403), light energy adsorption (r = -0.477) and its utilization at the reaction centers of PSII (r = -0.452) was manifested. The performance indices (PIABS and PIABS_total) positively correlated with part of grain in total biomass (0.571 and 0.418, respectively) and were higher in covered oats (by 28.2 and 21.9%, respectively).Conclusion. The existence of significant differences was shown between covered and naked oats according to six of the nine evaluated structural and functional parameters of the PSII leaf functioning. The results of the cluster analysis demonstrated the tendency to the grouping of genotypes by the presence/absence of grain hullness

High pressure torsion induced structural transformations in Ti- and Zr-based amorphous alloys

The melt-spun (MS) Ti50Ni25Cu25 alloy and the Zr62Cu22A110Fe5Dy1 bulk metallic glass (BMG) were subjected to high pressure torsion (HPT). X-ray diffraction (XRD) measurements show a shift of the first diffraction halo to a low angle after HPT processing, which corresponds to an increase in the values of the radius of the first coordination sphere and the free volume. Direct density measurements confirmed an increase in free volume values. A special TEM procedure was used for a detailed study of the microstructure of both amorphous alloys after HPT processing. The study revealed the formation of a large density of shear bands (SBs) in both alloys. Nanocrystals are formed directly in shear bands as a result of strain-inducted nanocrystallization. Amorphous nanoclusters with a size of 20 nm are formed in an amorphous matrix surrounding the SBs in the HPT-processed MS alloy Ti50Ni25Cu25. The formation of nanoclusters was not observed in BMG Zr62Cu22A110Fe5Dy1 after HPT processing

Free volume measurement of severely deformed Zr62Cu22Al10Fe5Dy1 bulk metallic glass

The Zr62Cu22Al10Fe5Dy1 bulk metallic glass (BMG) was subjected to high pressure torsion (HPT) at room temperature and at 150 °C. XRD shows a shift of first amorphous halo towards a low angles, which corresponds to an increase in the first coordination sphere radius and an increase in free volume content approximately by 0.44 % and 0.74 % after HPT processing at temperatures of 20 and 150 °C, respectively. Direct density measurements revealed that HPT at 20 °C and 150 °C leads to a decrease in the density values by 2.1% and 1 %, respectively, in comparison with the initial state. Value of density decrease for state HPT 150 °C estimated by direct density measurements is close to value of free volume increase estimated by shift of first amorphous halo

Investigation of the Deformation Activation Volume of an Ultrafinegrained Ti50Ni50 Alloy

© 2015 Springer Science+Business Media New York The mechanical properties, strain rate sensitivity (m) and deformation activation volume (ΔV) are investigated at the experimental temperatures from 20 to 400°С in a Ti50Ni50alloy in a coarse-grained (CG) state with the austenite grain size D = 200 μm and in an ultrafine-grained (UFG) state with D = 700 μm following an ECAP treatment. It is observed that this treatment improves the yield strength of the alloy compared to its CG-state. The strain rate sensitivity, m, is found to be by a factor of 1.5–2 higher than that of CG-specimens; it increases with the temperature in both states of the material. As the temperature of the material in tension increases up to Т = 150–250°С, parameter ΔV increases to its maximum and with a further growth of the experimental temperature to 400°С, parameter ΔV decreases. The deformation activation volume of the alloy in the UFG-state is by a factor of 2–4 larger than that in the CG-state for the same experimental temperatures

Determination of the Dependence of the Structure of the TiNi Alloy on the Conditions of Corrosion Tests

Коррозионный процесс протекал на всех образцах и во всех растворах в виде появления питтингов. При испытаниях в растворе 1М HCl заметно увеличение размера питтингов с 1,9 мкм в закаленном состоянии до 2,2 мкм в деформированном состоянии. С повышением концентрации раствора размеры питтингов растут: в закаленном состоянии — 2,3 мкм, а в деформированном — 3,5 мкм.The corrosion process proceeded in all samples and in all solutions in the form of pitting. When tested in a 1M HCl solution, an increase in the pitting size from 1.9 .m in the hardened state to 2.2 .m in the deformed state is noticeable. With an increase in the concentration of the solution, the dimensions of the pits grow: in the hardened state — 2.3 .m, and in the deformed state — 3.5 .m.Исследование поддержано средствами гранта Президента Российской Федерации для государственной поддержки молодых российских ученых — кандидатов наук (МК-6202.2021.1.2).The research was supported by a grant from the President of the Russian Federation for state support of young Russian scientists — candidates of sciences (MK‑6202.2021.1.2)

Microstructure transformation in a cast Cu-Fe alloy at high pressure torsion deformation

© 2016 Advance Study Center Co. Ltd.The effect of high pressure torsion (HPT) on the microstructure of Cu-Fe 36 wt.% alloy has been studied. The initial Cu-Fe alloy has a dendritic structure, the length of dendrites is up to 100 μm. As a result of HPT (20 anvil revolutions at 400 °C) a nanostructural state is formed. The average size of the Cu and α-Fe grains is 60 and 35 nm correspondingly. The volume fraction of the Fe phase reduces from the initial 37% down to 15% after HPT. The concentration of iron dissolved in the copper lattice reaches 20%. The subsequent annealing at 700 °C for 1 hour results in some coarsening of α-Fe particles, as compared to the state after HPT. However, the typical dendritic structure of the cast alloy does not recover; it remains dispersed with the size of α-Fe particles less than 20 μm. As a result of HPT the alloy microhardness increased from 1800 to 4000 MPa. The subsequent annealing at T = 700 °C decreased the microhardness to 2700 MPa, but this value is 1.5 times higher than that in the initial as cast state

База структурных данных по химии ВИНИТИ РАН. Вопросы формирования, эксплуатации и создания информационных продуктов

The authors describe the Structural Database (SD) in chemistry supported by the All-Russian Institute of Scientific and Technical Information of the Russian Academy of Sciences (VINITI RAS). The SD history, content, data formats and software are characterized in brief. The database development technologies based exclusively on digital media, are described. The techniques and software for adapting SD retrocollections to advanced software are discussed. The SD products are characterized, i. e. online structured search system, autonomous structured search system, autonomous system for chemical reaction search, e-dictionary of named reactions. The advantage of autonomous systems for searching chemical structures and reactions is that they can be installed on PCs. The SD-based information products can be used in fundamental and applied chemical studies, in chemical industry, education, and in information support of databases, sci-tech libraries and publishers’. The SD array may be applied in the studies based on the vast amount of factual information.В статье описана База структурных данных по химии ВИНИТИ РАН (База СД). Представлены краткая история создания Базы СД, её содержание, форматы данных и программное обеспечение. Дано описание современных технологий пополнения Базы СД, в основе которых лежит работа исключительно с электронными носителями информации. Представлены методы и программы адаптации данных ретрофонда Базы СД к современному программному обеспечению. Рассмотрены информационные продукты, получаемые на основе Базы СД: система структурного поиска в интерактивном режиме, автономная система структурного поиска, автономная система поиска химических реакций, электронный справочник химических соединений, электронный справочник именных реакций. Достоинством автономных систем поиска химических структур и реакций является то, что они могут работать на обычных персональных компьютерах. Представленные информационные продукты, получаемые на основе данных Базы СД, могут использоваться при проведении фундаментальных и прикладных исследований по химии, в химической промышленности, в учебном процессе, в качестве информационного обеспечения баз данных, научных библиотек, издательств. Массив данных Базы СД может использоваться в различных научных исследованиях, требующих большого объёма фактической информации.

Evolution of microstructure, macrotexture and mechanical properties of commercially pure Ti during ECAP-conform processing and drawing

Long-length ultrafine-grained (UFG) Ti rods are produced by equal-channel angular pressing via the conform scheme (ECAP-C) at 200 °C, which is followed by drawing at 200 °C. The evolution of microstructure, macrotexture, and mechanical properties (yield strength, ultimate tensile strength, failure stress, uniform elongation, elongation to failure) of pure Ti during this thermo-mechanical processing is studied. Special attention is also paid to the effect of microstructure on the mechanical behavior of the material after macrolocalization of plastic flow. The number of ECAP-C passes varies in the range of 1–10. The microstructure is more refined with increasing number of ECAP-C passes. Formation of homogeneous microstructure with a grain/subgrain size of 200 nm and its saturation after 6 ECAP-C passes are observed. Strength properties increase with increasing number of ECAP passes and saturate after 6 ECAP-C passes to a yield strength of 973 MPa, an ultimate tensile strength of 1035 MPa, and a true failure stress of 1400 MPa (from 625, 750, and 1150 MPa in the as-received condition). The true strain at failure failure decreases after ECAP-C processing. The reduction of area and true strain to failure values do not decrease after ECAP-C processing. The sample after 6 ECAP-C passes is subjected to drawing at 200¯C resulting in reduction of a grain/subgrain size to 150 nm, formation of (10 1¯0) fiber texture with respect to the rod axis, and further increase of the yield strength up to 1190 MPa, the ultimate tensile strength up to 1230 MPa and the true failure stress up to 1600 MPa. It is demonstrated that UFG CP Ti has low resistance to macrolocalization of plastic deformation and high resistance to crack formation after necking

Natural disasters in the history of the eastern Turk empire

This article analyzes the effect of climate extremes on the historical processes that took place (AD 536, 581, 601, 626 and 679) in the Eastern Turk Empire (AD 534–745) in Inner Asia. Climate extremes are sharp, strong and sometimes protracted periods of cooling and drought caused by volcanic eruptions that in this case resulted in a negative effect on the economy of a nomadic society and were often accompanied by famine and illness. In fact, many of these natural catastrophes coincided with the Black Death pandemics among the Eastern Turks and the Chinese living in the north of China. The Turk Empire can be split into several chronological periods during which significant events that led to changes in the course of history of the nomadic state took place: AD 534–545—the rise of the Turk Empire; AD 581–583—the division of the Turk Empire into theWestern and the Eastern Empires; AD 601–603—the rise of Qimin Qaghan; AD 627–630—the Eastern Turks are conquered by China; AD 679–687—the second rise of the Eastern Turk Empire. The research shows that there is clearly-discernable interplay between important historical events and climate extremes in the history of the Turk Empire. This interplay has led us to the conclusion that the climatic factor did have an impact on the historical processes that took place in the eastern part of Inner Asia, especially on the territories with a nomadic economy. © The Author(s) 2019