Analysis of Structure Destroyed Metal after Diffusion Heat Treatment

It was accomplished research of the structure steel which carbonitriding and subsequent heat treatment was exposed for its cause's destruction to discover. For measure quality field of metal were used methods optical, appearing electronic microscopy and X-ray diffraction. Therefore one of the principal problems were research phase composition, grain and dislocation structure of a metal the gear teeth. Mechanism of rising hear cracks in the gear teeth on different stages her making and their trajectories of evolution were determined

Thin structure of steel St52, 3N and possible reasons of defect of large-capacity billets AT "YURMASH"

Electron-microscopic and x-ray investigations of structurally-phase and intense-deformed condition of material made of defective and conditional forged billet at «Yurmash» have been carried out. It is ascertained that in steel made from the defective forged piece the fraction of perlite is 1,5...2 times higher and lamellar perlite prevails. Local long-range tensions in both conditions of material are commensurable with fluidity limit. The content of sulfides is considerably higher in the steel made from the defective billet. They are located in the body of ferrite grains and along the interfaces. In the material made from the conditional forging they are located only inside of grains. The scalar density of dislocations in ferrite grains and in ferrite layers of perlite of the defected billet is one and a half time higher than in conditional metal. All the totality of the listed above circumstances allows stating that the main cause of cracking of large-capacity billets made of steel St52, 3N is not a full conformity of the chemical compound to branded requirements

Adenosine and lymphocyte regulation

Adenosine is a potent extracellular messenger that is produced in high concentrations under metabolically unfavourable conditions. Tissue hypoxia, consequent to a compromised cellular energy status, is followed by the enhanced breakdown of ATP leading to the release of adenosine. Through the interaction with A2 and A3 membrane receptors, adenosine is devoted to the restoration of tissue homeostasis, acting as a retaliatory metabolite. Several aspects of the immune response have to be taken into consideration and even though in general it is very important to dampen inflammation, in some circumstances, such as the case of cancer, it is also necessary to increase the activity of immune cells against pathogens. Therefore, adenosine receptors that are defined as ‘sensors–of metabolic changes in the local tissue environment may be very important targets for modulation of immune responses and drugs devoted to regulating the adenosinergic system are promising in different clinical situations

Shaping immune responses through the activation of dendritic cells–P2 receptors

Dendritic cells (DCs) activate and shape the adaptive immune response by capturing antigens, migrating to peripheral lymphoid organs where naïve T cells reside, expressing high levels of MHC and costimulatory molecules and secreting cytokines and chemokines. DCs are endowed with a high degree of functional plasticity and their functions are tightly regulated. Besides initiating adaptive immune responses, DCs play a key role in maintaining peripheral tolerance toward self-antigens. On the basis of the information gathered from the tissue where they reside, DCs adjust their functional activity to ensure that protective immunity is favoured while unwanted or exaggerated immune responses are prevented. A wide variety of signals from neighbouring cells affecting DC functional activity have been described. Here we will discuss the complex role of extracellular nucleotides in the regulation of DC function and the role of P2 receptors as possible tools to manipulate immune responses

Purinergic signalling and immune cells

This review article provides a historical perspective on the role of purinergic signalling in the regulation of various subsets of immune cells from early discoveries to current understanding. It is now recognised that adenosine 5'-triphosphate (ATP) and other nucleotides are released from cells following stress or injury. They can act on virtually all subsets of immune cells through a spectrum of P2X ligand-gated ion channels and G protein-coupled P2Y receptors. Furthermore, ATP is rapidly degraded into adenosine by ectonucleotidases such as CD39 and CD73, and adenosine exerts additional regulatory effects through its own receptors. The resulting effect ranges from stimulation to tolerance depending on the amount and time courses of nucleotides released, and the balance between ATP and adenosine. This review identifies the various receptors involved in the different subsets of immune cells and their effects on the function of these cells

Neuroprotection by adenosine in the brain: From A1 receptor activation to A2A receptor blockade

Adenosine is a neuromodulator that operates via the most abundant inhibitory adenosine A1 receptors (A1Rs) and the less abundant, but widespread, facilitatory A2ARs. It is commonly assumed that A1Rs play a key role in neuroprotection since they decrease glutamate release and hyperpolarize neurons. In fact, A1R activation at the onset of neuronal injury attenuates brain damage, whereas its blockade exacerbates damage in adult animals. However, there is a down-regulation of central A1Rs in chronic noxious situations. In contrast, A2ARs are up-regulated in noxious brain conditions and their blockade confers robust brain neuroprotection in adult animals. The brain neuroprotective effect of A2AR antagonists is maintained in chronic noxious brain conditions without observable peripheral effects, thus justifying the interest of A2AR antagonists as novel protective agents in neurodegenerative diseases such as Parkinson’s and Alzheimer’s disease, ischemic brain damage and epilepsy. The greater interest of A2AR blockade compared to A1R activation does not mean that A1R activation is irrelevant for a neuroprotective strategy. In fact, it is proposed that coupling A2AR antagonists with strategies aimed at bursting the levels of extracellular adenosine (by inhibiting adenosine kinase) to activate A1Rs might constitute the more robust brain neuroprotective strategy based on the adenosine neuromodulatory system. This strategy should be useful in adult animals and especially in the elderly (where brain pathologies are prevalent) but is not valid for fetus or newborns where the impact of adenosine receptors on brain damage is different

Destruction of nitrocarbonized steel

The it authors have studied the structure of steel subjected to carbonitriding and subsequent heat treatment to determine the reasons of its destruction. The mechanism of hear cracks initiation was defined and their evolution trajectories were determined

Sugar-beet complex of Russia: stateand directions of development

The complex estimation of state of sugar-beet complex of the Russian Federation has been made. The basic indices of sugar beet production and processing such as area under crop, yield, croppage, sugar content, forecasted sugar yield, and production of sugar from beet are presented. Particular attention has been given to the analysis of sugar-beet industry of the Central Federal District and its separate regions. A high potential of raw-material base development in Central Federal District and, in particular, Central Black-Earth Region has been revealed. Thus, in Russia, about 53% of sugar beet sown annually is located in Central Federal District. In the District, areas under the crop were 607.4 thousand hectares in 2016 and increased by 8.7% in comparison with 2015. Also, in the structure of croppages, Central Federal District has the greatest position as providing 58.5% of overall production, and the Central Black Earth Region рrоduсеs 88–89% of the District sugar beet croppage. Over the period of 2005–2014, Central Federal District has surpassed Privolzhsky Federal District by 23.3% and Siberian Federal District by 25.3% in sugar yield per 1 hectare; but it is slightly inferior to Southern Federal District and North-Caucasian Federal District in this respect (by 3 and 12.6% accordingly). These achievements were promoted by favorable soil and environmental conditions during vegetation and harvesting of sugar beet, perfection of the crop cultivation technology and modernization of sugar industry. On the whole, Russia is the leader in beet sugar production (5 million tons) that provides 90% level of self-sufficiency. Strengthening of material and technical base, as well as development and introduction of resources-economy technologies can become the priority directions of the sugar-beet complex steady development in an effort to realize the policy of imported products substitution