Features of verbal communication of the Tajik youth in social networks

Within the framework of this article, the author presents materials of empirical research on the features of verbal communication of Tajik youth in social networks. Data of content analysis is given. The author of the article comes to the conclusion that the written speech of the Tajik users of social networks is different. Written speech of Tajik users of networks in their native language is diverse, in Russian it is simple, monotonous

The synthesis of multi-loop control systems for a precision lathe by numerical method

The article deals with the problem of the synthesis of multi-loop control system. Modern methods of the synthesis of multi-loop control systems do not provide the control with prescribed accuracy. This paper combines real interpolation method and numerical method

ПРО ОДИН З АСПЕКТІВ КОМПЛЕКСНОГО ВИРІШЕННЯ ПИТАННЯ БУДІВНИЦТВА КАНАЛУ АЗОВСЬКЕ МОРЕ – МОЛОЧНИЙ ЛИМАН

Молочний лиман – один з найбільш цінних водно-болотних угідь Приа-зов’я, який увійшов до Міжнародного кадастру Рамсарських територій. Згідно з фізико-географічним районуванням України, Молочний лиман відноситься до Присивасько-Приазовської степової області Причорноморської південно-степової провінції. Адміністративно ця акваторія знаходиться в Запорізькій об-ласті і розташована на територіях Якимівського, Приазовського та Мелітополь-ського районів. Довжина лиману складає 32 км, максимальна ширина 8 км, гли-бина до 3 м, площа 170 км2. Від Азовського моря Лиман відділений косою Пе-ресип зі штучно створеною протокою (промоїною). Останнім часом, з`єднувальний канал Молочного лиману практично не функціонує

Research of molybdenum carbide by raman spectroscopy

Molybdenum carbides crystalline phases are well-known polymorphs with useful technological applications including sensors, electronics, and catalysis. According to Mo-C known phase diagram, several polymorphs can exist under ambient conditions. One of the promising synthesis techniques is DC arc plasma. Nowadays, recent trends focus on the non-vacuum arcing procedure in ambient conditions which is possible due to carbon monoxide generation during the synthesis process. This phenomenon as a result of graphite electrodes usage can prevent the oxidation of the synthesis products. As an advantage of this method should be noted the possible cost benefits through the lower energy consumption, also the productivity can be increased by our approach. In this contribution, the arc plasma method is investigated for the crystalline molybdenum carbides synthesis. According to the X-ray diffraction results, the Mo2C and Mo1.2C0.8 crystalline phases were synthesized. Raman spectroscopy confirms the presence and high crystallinity of these MoC phases. This work shows an inexpensive and promising way to obtain molybdenum carbides with potential in optoelectronics, environmental, and energy applications

The Role of Photolabile Dermal Nitric Oxide Derivates in Ultraviolet Radiation (UVR)-Induced Cell Death

Human skin is exposed to solar ultraviolet radiation comprising UVB (280–315 nm) and UVA (315–400 nm) on a daily basis. Within the last two decades, the molecular and cellular response to UVA/UVB and the possible effects on human health have been investigated extensively. It is generally accepted that the mutagenic and carcinogenic properties of UVB is due to the direct interaction with DNA. On the other hand, by interaction with non-DNA chromophores as endogenous photosensitizers, UVA induces formation of reactive oxygen species (ROS), which play a pivotal role as mediators of UVA-induced injuries in human skin. This review gives a short overview about relevant findings concerning the molecular mechanisms underlying UVA/UVB-induced cell death. Furthermore, we will highlight the potential role of cutaneous antioxidants and photolabile nitric oxide derivates (NODs) in skin physiology. UVA-induced decomposition of the NODs, like nitrite, leads not only to non-enzymatic formation of nitric oxide (NO), but also to toxic reactive nitrogen species (RNS), like peroxynitrite. Whereas under antioxidative conditions the generation of protective amounts of NO is favored, under oxidative conditions, less injurious reactive nitrogen species are generated, which may enhance UVA-induced cell death

Biologische Aspekte der nicht-enzymatischen Stickstoffmonoxid-Generierung durch UVA-induzierten Nitritzerfall in humanen Hautfibroblasten

Nitric oxide (NO•) plays a pivotal role in the physiology of the human skin and is involved in many biological processes like tanning, wound healing as well as the proliferation and differentiation of keratinocytes and fibroblasts. Furthermore NO• can act as a cell protective agent and prevent effectively e.g. from UVA-induced apoptosis. NO• can be produced in vivo enzymatically by NO-synthases. Additionally NO can generated in high quantities by enzyme independently UV- and pH-induced decomposition of naturally occurring NO-derivates (NOD) like nitrite and nitroso-compounds. Function and mechanism of non-enzymatic NO-generation in human skin is largely unknown. Within this work we could show for the first time that under physiological conditions UVA-radiation can decompose effectively nitrite anions, which result in NO-formation. During nitrit decomposition occur reactive intermediates which react with NO and decrease that way the NO-generation. But an elimination of this intermediates by strong antioxidants leads to a maximal yield of NO. In a further approach we examined the optional use of the non-enzymatic NO-generation from nitrite as a NO-donor system again UVA-induced cell damage in human skin fibroblasts. Contrary to our experience with rat cells supraphysiological concentrations of nitrite up 100 mM already leaded to a significant increase of UVA-induced cell damage. We could identify NO2• as the toxic component. Alteration of the NO•/ NO2• ratio by exogenous addition of NO or NO2•-Scavenger like ascorbic acid, however, leaded to a protection from the sawn UVA/nitrite-induced cell death. Hence we could demonstrate for the first time that the UVA-induced decomposition of nitrite can be used as a cell protection system, if the resulting toxic intermediates can be prevented or eliminated. Interestingly glutathione and trolox, two potent NO2•-scavengers, caused an increase of the UVA/nitrite-induced toxicity. The UVA-induced generation of glutathionyl-radicals by glutathion and phenoxyl-radicals by trolox respectively in the presence of nitrite can explain these paradoxical results. Thus, our results show impressively that supposed protective substances can become toxic in redox-depending systems. In a further characterisation of the physiological role of naturally intracellular occurring NOD, we could show the first time by using Laserscanning-Microskop-Technique, that UVA-radiation can generate intracellulary NO by decomposition of nitrite. Fibroblasts cultures which nitrite-amount had been reduced experimentally, revealed a lower UVA-induced intracellular NO-formation accompanied by a significant higher susceptibility to UVA-induced cell damage. Substitution of the nitrite-depleted cells with physiological concentration of nitrite (10 µM), however, could restore this higher susceptibility. So we demonstrate for the first time that intracellular, photolabiles NO-derivates like nitrite take place in cell protection against UVA-radiation and that non-enzymatic NO-generation by nitrite-decomposition is a naturally rapidly acting principle in the human skin

Biologische Aspekte der nicht-enzymatischen Stickstoffmonoxid-Generierung durch UVA-induzierten Nitritzerfall in humanen Hautfibroblasten

Nitric oxide (NO•) plays a pivotal role in the physiology of the human skin and is involved in many biological processes like tanning, wound healing as well as the proliferation and differentiation of keratinocytes and fibroblasts. Furthermore NO• can act as a cell protective agent and prevent effectively e.g. from UVA-induced apoptosis. NO• can be produced in vivo enzymatically by NO-synthases. Additionally NO can generated in high quantities by enzyme independently UV- and pH-induced decomposition of naturally occurring NO-derivates (NOD) like nitrite and nitroso-compounds. Function and mechanism of non-enzymatic NO-generation in human skin is largely unknown. Within this work we could show for the first time that under physiological conditions UVA-radiation can decompose effectively nitrite anions, which result in NO-formation. During nitrit decomposition occur reactive intermediates which react with NO and decrease that way the NO-generation. But an elimination of this intermediates by strong antioxidants leads to a maximal yield of NO. In a further approach we examined the optional use of the non-enzymatic NO-generation from nitrite as a NO-donor system again UVA-induced cell damage in human skin fibroblasts. Contrary to our experience with rat cells supraphysiological concentrations of nitrite up 100 mM already leaded to a significant increase of UVA-induced cell damage. We could identify NO2• as the toxic component. Alteration of the NO•/ NO2• ratio by exogenous addition of NO or NO2•-Scavenger like ascorbic acid, however, leaded to a protection from the sawn UVA/nitrite-induced cell death. Hence we could demonstrate for the first time that the UVA-induced decomposition of nitrite can be used as a cell protection system, if the resulting toxic intermediates can be prevented or eliminated. Interestingly glutathione and trolox, two potent NO2•-scavengers, caused an increase of the UVA/nitrite-induced toxicity. The UVA-induced generation of glutathionyl-radicals by glutathion and phenoxyl-radicals by trolox respectively in the presence of nitrite can explain these paradoxical results. Thus, our results show impressively that supposed protective substances can become toxic in redox-depending systems. In a further characterisation of the physiological role of naturally intracellular occurring NOD, we could show the first time by using Laserscanning-Microskop-Technique, that UVA-radiation can generate intracellulary NO by decomposition of nitrite. Fibroblasts cultures which nitrite-amount had been reduced experimentally, revealed a lower UVA-induced intracellular NO-formation accompanied by a significant higher susceptibility to UVA-induced cell damage. Substitution of the nitrite-depleted cells with physiological concentration of nitrite (10 µM), however, could restore this higher susceptibility. So we demonstrate for the first time that intracellular, photolabiles NO-derivates like nitrite take place in cell protection against UVA-radiation and that non-enzymatic NO-generation by nitrite-decomposition is a naturally rapidly acting principle in the human skin