Critical Redistribution of Nitrogen in the Austenitic Cr-Mn Steel under Severe Plastic Deformation

A narrow temperature range of changes in the mechanism and kinetics of structural-phase transformations during mechanical alloying under deformation in rotating Bridgman anvils was determined by the methods of Mössbauer spectroscopy, electron microscopy, and mechanical tests in the high-nitrogen chromium-manganese steel FeMn22Cr18N0.83. The experimentally established temperature region is characterized by a change in the direction of nitrogen redistribution—from an increase in the N content in the metal matrix during cold deformation to a decrease with an increase in the temperature and degree of severe plastic deformation. The change in the direction of nitrogen redistribution is due to the acceleration of the decomposition of a nitrogen-supersaturated solid solution of austenite with the formation of secondary nanocrystalline nitrides. The presence of a transition region for the mechanism of structural-phase transitions is manifested in the abnormal behavior of the mechanical properties of steel.

Molecular Regulatory Networks for Improving Nitrogen Use Efficiency in Rice

Nitrogen is an important factor limiting the growth and yield of rice. However, the excessive application of nitrogen will lead to water eutrophication and economic costs. To create rice varieties with high nitrogen use efficiency (NUE) has always been an arduous task in rice breeding. The processes for improving NUE include nitrogen uptake, nitrogen transport from root to shoot, nitrogen assimilation, and nitrogen redistribution, with each step being indispensable to the improvement of NUE. Here, we summarize the effects of absorption, transport, and metabolism of nitrate, ammonium, and amino acids on NUE, as well as the role of hormones in improving rice NUE. Our discussion provide insight for further research in the future.

Scientific Challenges on Theory of Fat Burning by Exercise

GRAPHICAL ABSTRACTExercise decreases abdominal fat mass, especially at high intensity. This outcome is not causally associated with fat burning, but better explained by carbon and nitrogen redistribution. Since abdominal fat tissue constantly releases fatty acids into circulation under post-absorptive condition with natural cell deaths, exercise diverts more post-meal carbon and nitrogen to muscle for energy repletion and cell regeneration after phagocytosis and stem cell homing. This in turn leads to concurrent fat mass loss and muscle mass gain. Respiratory ventilation during high-intensity aerobic exercise amplifies the competition for post-meal carbon and nitrogen against adipose tissues.

Inversion of Nitrogen Redistribution in Austenitic Steel by Severe Plastic Deformation

Using the Mössbauer spectroscopy and transmission electron microscopy (TEM) methods, the temperature boundary of a strain-induced transformation with the inversion of the direction of nitrogen redistribution is determined in the structure of the FeMn22Cr18N0.83 austenitic steel. Deformation by high pressure torsion in Bridgman anvils below the temperature limit (298 K) leads to an increase in the amount of nitrogen in the interstitial solid solution and deformation above the limit (373 K) leads to a decrease in this value. An increase in the deformation temperature leads to the complete dissolution of the products of cellular decomposition and the formation of submicrocrystalline austenite with secondary nanocrystalline nitrides. Changes in the direction of nitrogen redistribution are explained by the competition between the mechanisms of relaxation of the structure along the paths of dispersion, dissolution of nitrides by dislocation, and decomposition of a solid solution supersaturated with nitrogen.

Isotopic Tracers Unveil Distinct Fates for Nitrogen Sources during Wine Fermentation with Two Non-Saccharomyces Strains

Non-Saccharomyces yeast strains have become increasingly prevalent in the food industry, particularly in winemaking, because of their properties of interest both in biological control and in complexifying flavour profiles in end-products. However, unleashing the full potential of these species would require solid knowledge of their physiology and metabolism, which is, however, very limited to date. In this study, a quantitative analysis using 15N-labelled NH4Cl, arginine, and glutamine, and 13C-labelled leucine and valine revealed the specificities of the nitrogen metabolism pattern of two non-Saccharomyces species, Torulaspora delbrueckii and Metschnikowia pulcherrima. In T. delbrueckii, consumed nitrogen sources were mainly directed towards the de novo synthesis of proteinogenic amino acids, at the expense of volatile compounds production. This redistribution pattern was in line with the high biomass-producer phenotype of this species. Conversely, in M. pulcherrima, which displayed weaker growth capacities, a larger proportion of consumed amino acids was catabolised for the production of higher alcohols through the Ehrlich pathway. Overall, this comprehensive overview of nitrogen redistribution in T. delbrueckii and M. pulcherrima provides valuable information for a better management of co- or sequential fermentation combining these species with Saccharomyces cerevisiae.

Metabolic Profiling of γ-Irradiated Barley Plants Identifies Reallocation of Nitrogen Metabolism and Metabolic Stress Response

The favorable responses of crop species to low-dose γ irradiation can help to develop cultivars with increased productivity and improved stress tolerance. In the present study, we tried to reveal the candidate metabolites involved in growth stimulation of barley seedlings after applying low-dose γ-radiation (60Co) to seeds. Stimulating doses (5-20 Gy) provided a significant increase in shoot length and biomass, while relatively high dose of 100 Gy led to significant inhibition of growth. Gas chromatography–mass spectrometry metabolomic analysis uncovered several compounds that may take part in radiation hormesis establishment in irradiated plants. This includes molecules involved in nitrogen redistribution (arginine, glutamine, asparagine, and γ-aminobutyric acid) and stress-responsive metabolites, such as ascorbate, myo-inositol and its derivates, and free amino acids (l-serine, β-alanine, pipecolate, and GABA). These results contribute to the understanding of the molecular mechanisms of hormesis phenomenon.

Approach of monocarpic senescence control by nitrogen manipulation in mungbean and cowpea

Pods start growing almost at the same time and mature simultaneously in soybean (Glycine max (L.) Merrill) plants. But mungbean (Vigna radiata L. Wilczek) and cowpea (Vigna sinensis Endl.) perform unsynchronized pod maturity. To overcome unsynchronized pod maturity the nitrogen redistribution aspects of mungbean and cowpea were investigated based on the linkage of soybean. Pot experiment was conducted using a nodulating mungbean variety (cv. XANH NINH THUAN) in 2015 and cowpea variety (cv. IT98K-205-8) in 2016 in the vinyl house at Saga University in Japan. During the experiment, nutrient solution was applied by changing nitrogen concentrations to 5, 25 and 100 ppm (control). Mungbean plants provided with low concentration of 5 and 25 ppm of nitrogen supply was not capable to produce continuous pods. Cowpea plants supplied with low concentration of nitrogen was also unable to produce successful pods continuously. Insufficient nitrogen hampered the continuation of pod setting in both the cases, might be due to, all the vegetative stored nitrogen had been utilized for seed development during the vegetative phase before pod setting. In case of 100 ppm nitrogen supply, for both mungbean and cowpea, no senescence and nitrogen remobilization occurred. However, researches showed that soybean typically undergoes the remobilization evidence, i.e., monocarpic senescence, in 100 ppm of nitrogen supply. J.Bangladesh Agril. Univ. 16(3): 386–395, December 2018