Synthesis and characterisation of nanocrystalline ZrN PVD coatings on AISI 430 stainless steel

The nanocrystalline films of zirconium nitride have been synthesized using ion-plasma vacuum-arc deposition technique in combination with high-frequency discharge (RF) on AISI 430 stainless steel at 150oC. Structure examinations X-ray fluorescent analysis (XRF), X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) with microanalysis (EDS), and transmission electron microscopy (TEM), nanoidentation method – were performed to study phase and chemical composition, surface morphology, microstructure and nanohardness of coatings. The developed technology provided low-temperature coatings synthesis, minimized discharge breakdown decreasing formation of macroparticles (MPs) and allowed to deposit ZrN coatings with hardness variation 26.6…31.5 GPa. It was revealed that ZrN single-phase coatings of cubic modification with finecrystalline grains of 20 nm in size were formed

Anti-corrosion ceramic coatings on the surface of Nd-Fe-B repelling magnets

The results of vacuum-arc deposition of thin ZrO₂coatings to protect the surface of Nd-Fe-B permanent magnets used as repelling devices in orthodontics are presented. The structure, phase composition and mechanical properties of zirconium dioxide films have been investigated by means of SEM, XRD, EDX, XRF and nanoindentation method. It was revealed the formation of polycrystalline ZrO₂ films of monoclinic modification with average grain size 25 nm. The influence of the ZrO₂ coating in terms of its barrier properties for corrosion in quasi-physiological 0.9 NaCl solution has been studied. Electrochemical measurements indicated good barrier properties of the coating on specimens in the physiological solution environment

Метилювання положення 8 піридинової частини молекули N-(бензил)-2-гідрокси-4-оксо-4Н-піридо[1,2-a]піримідин-3-карбоксамідів як спроба посилення їх аналгетичних властивостей

The chemical modification of the pyridine moiety of the molecule – displacement of the methyl group in position 8 of pyrido[1,2-a]pyrimidine nucleus has been considered as one of the possible versions to optimize the biological properties of N-(benzyl)-2-hydroxy-4-oxo-4H-pyrido[1,2-a]pyrimidine-3-carboxamides. The synthesis of the research targets was carried out by the reaction of the corresponding benzylamines and ethyl 2-hydroxy-8-methyl-4-oxo-4H-pyrido[1,2-a] pyrimidine-3-carboxylate, in its turn obtained by condensation of 2-amino-4-methylpyridine (i.e. the product with the methyl group in the intentionally required position) and triethyl methanetricarboxylate. The structure of the compounds obtained has been confirmed by the data of elemental analysis and NMR 1H spectroscopy, and in the case of optically active 1-phenylethylamides additionally by polarimetry. The study of the analgesic properties of all N-(benzyl)-2-hydroxy-8-methyl-4-oxo-4H-pyrido[1,2-a]pyrimidine-3-carboxamides was performed on the standard experimental “acetic acid writhing” model. At the same time, it has been found that our modification is accompanied with the increased biological activity of exclusively para-substituted derivatives. For profound research 4-fluorobenzylamide exceeding Piroxicam and Nabumetone by the level of the specific effect has been recommended as a potential new analgesic.В качестве одного из возможных вариантов оптимизации биологических свойств N-(бензил)-2-гидрокси-4-оксо-4Н-пиридо[1,2-a]пиримидин-3-карбоксамидов рассмотрена химическая модификация пиридиновой части их молекулы – перемещение метильной группы в положение 8 пиридо[1,2-a]пиримидинового ядра. Синтез целевых объектов исследования осуществлен реакцией соответствующих бензиламинов с этил-2-гидрокси-8-метил-4-оксо-4Н-пиридо[1,2-a]пиримидин-3-карбоксилатом, в свою очередь, полученным конденсацией 2-амино-4-метилпиридина (т. е. продукта с метильной группой в заведомо требуемом положении) с триэтилметантрикарбоксилатом. Строение синтезированных веществ подтверждено данными элементного анализа и спектроскопии 1Н ЯМР, а в случае оптически активных 1-фенилэтиламидов дополнительно еще и поляриметрически. Изучение анальгетических свойств всех N-(бензил)-2-гидрокси-8-метил-4-оксо-4Н-пиридо[1,2-a]пиримидин-3-карбоксамидов проведено на стандартной экспериментальной модели уксуснокислых корчей. При этом найдено, что предпринятая нами модификация сопровождается усилением биологической активности исключительно паразамещенных производных. Для углубленных испытаний в качестве нового потенциального анальгетика рекомендован 4-фторбензиламид, превосходящий по уровню специфического эффекта Пироксикам и Набуметон.Як один з можливих варіантів оптимізації біологічних властивостей N-(бензил)-2-гідрокси-4-оксо-4Н-піридо[1,2-a]піримідин-3-карбоксамідів розглянуто хімічну модифікацію піридинової частини їх молекули – переміщення метильної групи у положення 8 піридо[1,2-a]піримідинового ядра. Синтез цільових об’єктів дослідження здійснено реакцією відповідних бензиламінів з етил-2-гідрокси-8-метил-4-оксо-4Н-піридо[1,2-a]піримідин-3-карбоксилатом, у свою чергу, одержаним конденсацією 2-аміно-4-метилпіридину (тобто продукту з метильною групою в завідомо необхідному положенні) з триетилметантрикарбоксилатом. Будову синтезованих речовин підтверджено даними елементного аналізу та спектроскопії 1Н ЯМР, а у випадку оптично активних 1-фенілетиламідів додатково ще й поляриметрично. Вивчення аналгетичних властивостей усіх N-(бензил)-2-гідрокси-8-метил-4-оксо-4Н-піридо[1,2-a]піримідин-3-карбоксамідів проведено на стандартній експериментальній моделі оцтовокислих корчів. При цьому знайдено, що здійснена нами модифікація супроводжується посиленням біологічної активності виключно паразаміщених похідних. Для поглиблених випробовувань як новий потенційний аналгетик рекомен

Some aspects of periodontitis pathogenesis in children.

Inflammatory processes in the tissues surrounding tooth root are frequent enough and develop as the direct complication of caries. As acute periodontitis is manifested with grinding toothache and violation of ph­y­sio­logical act of chewing, symptoms of general intoxication, the continuous sluggish chronic periodontitis is harmful and dangerous to the organism as well. It forms the state of chronic оdontogenetic intoxication and chroneosepsis with wrong functioning of some internal organs and body systems. The like complications can cause significant disturbance to the function of kidneys, liver, heart, joints and their treatment without ablating focus of inflammation is often in- effective; this must be taken into account by doctors-interns. However, scanning of the oral cavity by conservative means has its difficulties mostly because of ignoring pathogenesis of such inflammation. That is why activity of ferments of blood dehydrogenases from the periapical tissues of the teeth affected with the chronic periodontitis was studied. The level of succinate dehydrogenase and alpha-glycerophosphate degydrogenase of lymphocytes of 110 schoolchildren aged 13-17 years old was studied. The main group of examined individuals included those of infected with tuber­culousis – 50 individuals, and the control group (60 individuals) – clinically healthy ones without tuberculousis desease. All schoolchildren had 1 or 2 teeth affected with chronic periodontitis of the apical localization. The re­searchers found that a significant inhibition of activity of succinate dehydrogenase and alpha-glycerophosphate degydrogenase ferments occurs in the inflammatory periodontal tissues, which indicates to local immunity decline, and as a consequence, pathogenic bacteria activation. In people infected with tuberculousis these violations were  more developed. Such features of periodontitis pathogenesis must be taken into account when providing a combined treatment

RF-Magnetron sputtering of silicon carbide and silicon nitride films for solar cells

RF-magnetron nonreactive sputtering method from solid-phase target in argon atmosphere was used for obtaining thin silicon carbide and silicon nitride films, that are used for constructing solar cells based on substrates of single crystal silicon of p-typ

Vascular mechanism in the formation of diclophenac induced gastrotoxicity: the association with the level of hydrogen sulfide

Department of Pharmacology, N. I. Pirogov National Medical University of Vinnitsa, UkraineBackground: Non-steroid anti-inflammatory drugs (NSAIDs)-induced gastrotoxicity arises as a result of imbalance between vasodilator and vasoconstrictor bioregulators. The influence of deficiency and excess of hydrogen sulfide on vascular mechanisms in the formation of NSAIDs-induced gastrotoxicity was investigated. Material and methods: Male nonlinear rats underwent preconditioning with donor of H2S (NaHS) and inhibitor of its synthesis (propargilglycine). Diclophenac sodium was introduced orally (8 mg/kg). In homogenates of rats’ gastric mucosa was evaluated the activity of prostaglandin-H-synthase (PgH-synthase), NO-synthase, content of nitrites and nitrates, H2S and the activity of cystathionine-γ-lyase. In vitro H2S-induced relaxation of mesenteric arteries was measured. Results: Diclophenac sodium decreased cystathionine-γ-lyase enzyme activity, NO-synthase and PGH-synthase (by 17-24%), content of their H2S metabolites and nitrites/nitrates (by 20-22%) in gastric mucosa, and accompanied with the decrease of mesenteric artery sensitivity to vasodilatory action of H2S (EC50 increased to 27.5%). H2S deficiency – increases and excess of H2S – inhibits the negative influence of diclophenac on the production of vasoactive molecules and H2S-induced relaxation of mesenteric arteries. Conclusions: Excess of H2S in organism increases the content of vasoligating molecules and thus can prevent vascular disturbances caused by NSAIDs in rat stomach mucosa

Temperature influence on the properties of thin Si₃N₄ films

Applying Raman spectroscopy, small-angle x-ray scattering, and atomic force microscopy it were studied phase composition and surface morphology of nanoscale films Si₃N₄ (obtained by RF magnetron sputtering

N-фенетил-2-гідрокси-4-оксо-4Н-піридо[1,2-а]піримідин-3-карбоксаміди як можливі про- тивірусні агенти

Based on the preliminary calculated screening performed by the PASS programme the synthesis of the group of the corresponding N-phenethyl-2-hydroxy-4-oxo-4H-pyrido[1,2-a]pyrimidine-3-carboxamides as potential antiviral agents has been carried out by the interaction of ethyl esters of 2-hydroxy-4-oxo-4H-pyrido[1,2-a]pyrimidine-3-carboxylic acids with 2-arylethylamines in boiling ethanol. Their structure has been confirmed by the data of elemental analysis and NMR 1H spectroscopy. Of the Herpesviruses family such viruses as Herpes Simplex Viruses Type 1 and 2, Varicella-Zoster Virus, Epstein-Barr Virus, as well as Cytomegalovirus have been involved in the screening research. Influenza Virus was presented by two types: A (subtypes H1N1, H3N2, H5N1) and B. The group of viruses affecting different sections of the respiratory tract included Parainfluenza Virus, SARS Virus, Rhinovirus, Adenovirus and Respiratory Syncytial Virus. Besides, Measles Virus, Vaccinia Virus and related Cowpox Virus, Hepatitis B and C Viruses, as well as Venezuelan Equine Encephalitis Virus were involved. The group of viruses causing febrile states of varying severity in human was presented by Rift Valley Fever Virus, West Nile Virus, Yellow Fever Virus, Dengue Virus and Tacaribe Virus. According to the results of the tests performed N-(4-chlorophenethyl)- 2-hydroxy-4-oxo-4H-pyrido[1,2-a]pyrimidine-3-carboxamide has been recommended for further research. Having a low cytotoxicity this compound revealed a high antiviral activity in relation to the West Nile fever virus agent.На основании проведенного по программе PASS предварительного расчетного скрининга в качестве потенциальных противовирусных агентов взаимодействием этиловых эфиров 2-гидрокси-4-оксо-4Н-пиридо[1,2-а] пиримидин-3-карбоновых кислот с 2-арилэтиламинами в кипящем этиловом спирте осуществлен синтез группы соответствующих N-фенетил-2-гидрокси-4-оксо-4Н-пиридо[1,2-а]пиримидин-3-карбоксамидов. Их строение подтверждено данными элементного анализа и спектроскопии ЯМР 1Н. Из семейства герпесвирусов в скрининговых исследованиях были задействованы вирусы простого герпеса 1 и 2 типов, вирус Варицелла-Зостера, вирус Эпштейна-Барра, а также цитомегаловирус. Вирус гриппа был представлен двумя типами: А (подтипы H1N1, H3N2, H5N1) и В. Группа вирусов, поражающих различные отделы дыхательной системы, включала вирус парагриппа, вирус SARS, риновирус, аденовирус и респираторный синцитиальный вирус. Кроме того, были задействованы вирусы кори, коровьей оспы, родственный ему Cowpox вирус, вирусы гепатитов В и С, а также вирус Венесуэльского конского энцефалита. Группа вирусов, вызывающих у человека лихорадочные состояния различной степени тяжести, представлена вирусом лихорадки долины Рифт, вирусом Западного Нила, вирусом желтой лихорадки, вирусом Денге и вирусом Такарибе. По результатам проведенных испытаний для дальнейшего изучения рекомендован N-(4-хлорфенетил)-2-гидрокси-4- оксо-4H-пиридо-[1,2-a]пиримидин-3-карбоксамид. При низкой цитотоксичности это соединение проявило высокую противовирусную активность по отношению к возбудителю лихорадки Западного Нила.На підставі проведеного за програмою PASS попереднього розрахункового скринінгу як потенційні противірусні агенти взаємодією етилових естерів 2-гідрокси-4-оксо-4Н-піридо[1,2-а]піримідин-3-карбонових кислот з 2-арилетиламінами у киплячому етиловому спирті здійснено синтез групи відповідних N-фенетил- 2-гідрокси-4-оксо-4Н-піридо[1,2-а]піримідин-3-карбоксамідів. Їх будова підтверджена даними елементного аналізу та спектроскопії ЯМР 1Н. З сімейства герпесвірусів у скринінгових дослідженнях були задіяні віруси простого герпесу 1 та 2 типів, вірус Варіцелла-Зостера, вірус Епштейна-Барра, а також цитомегаловірус. Вірус грипу було представлено двома типами: А (підтипи H1N1, H3N2, H5N1) та В. Група вірусів, що викликають ураження різних відділів дихальної системи, включала вірус парагрипу, вірус SARS, риновірус, аденовірус та респіраторний синцитіальний вірус. Крім того, були задіяні віруси кору, коров’ячої віспи, споріднений йому Cowpox вірус, віруси гепатитів В і С, а також вірус Венесуельського кінського енцефаліту. Група вірусів, що викликають у людини лихоманки різного ступеня тяжкості, представлена вірусом лихоманки долини Рифт, вірусом Західного Нілу, вірусом жовтої лихоманки, вірусом Денге та вірусом Такарібе. За результатами проведених випробовувань для подальшого вивчення рекомендовано N-(4-хлорфенетил)- 2-гідрокси-4-оксо-4H-піридо[1,2-a]піримідин-3-карбоксамід. При низькій цитотоксичності ця сполука виявила високу противірусну активність по відношенню до збудника лихоманки Західного Нілу

Effect of aluminium on redox-homeostasis of common buckwheat (Fagopyrum esculentum)

Common buckwheat is a significant culture in Ukraine, whose importance for food security has increased in recent decades. An important biological feature of buckwheat is the ability of the crop to grow on poor and especially acidic soils. Common buckwheat was sown in Ukraine on the area of 125,000 ha in 2020, mainly in the central part of the country and in the soil-climatic zone Polesie in the north of the country. At the same time, the area under buckwheat cultivation has been steadily decreasing in the last decade, which is due to the low profitability of cultivation on mainly acidic soils. The research was conducted in the field conditions during 2012–2018 in Kiev region, as well as in laboratory conditions. ICP analysis and biochemical methods were used. Yield of buckwheat on light soils of low fertility depends largely on the level of acidity of the soil. On acidic sod-podzolic soils with loam substrate, the aluminum content of the layer is 20–40 cm higher, compared to a layer of 0–20 cm. This is probably one of the reasons why, when the concentration of aluminum in the soil profile is increased, the root system is located mainly in the upper layer of soil with a lower content of aluminum. In this case, the study of the mechanisms of resistance to the action of aluminum on acidic soils is an important component of the cost-effectiveness of crop production in the region. In acidic soils with pH < 5.0, phytotoxic aluminum (Al3+) rapidly inhibits root growth and afterwards negatively affects water and nutrient uptake in plants. Acquiring phytotoxic capacities, in this connection Al ions affect a wide range of cellular and molecular processes, with a consequent reduction in plant growth. In most plant species, reactive oxygen species (ROS) production can also be induced by Al toxicity leading to oxidative damage of biomolecules and biological membranes. We have detected an accumulation of Al ions in leaf tissues of treatment plants after 10 days of exposure. Tissues of F. esculentum roots contained 155.4% of control level of Al and tissues of F. esculentum leaves – 186.2% of control level of Al ions. Significant intensification of O2•– generation in roots and leaf tissues as a reaction to Al addition to nutrient solution was detected. Increase in antioxidant enzymes activities and non fixed products of lipids peroxidation was characterized as a biochemical defense reaction of F. esculentum over the 10 days of exposure to Al (50 μM). Thus, the results show that the action of 50 μM of Al ions activated antioxidant enzymes – SOD and CAT and decreased oxidative processes, thus promotes pro/antioxidant balance of common buckwheat. These mechanisms of redox homeostasis can be triggers of morphological changes in buckwheat plants, which lead to increased crop resistance when growing on acidic soils with high aluminum content. Thus, the resistance of culture to acid soils may be associated with the possibility of increased accumulation of aluminum in the plant’s tissues, as well as in changes in redox homeostasis with subsequent morphological changes, and primarily the formation of the root system in the top layer of soil with a reduced content of aluminum