Impact of High-Temperature, High-Pressure Synthesis Conditions on the Formation of the Grain Structure and Strength Properties of Intermetallic Ni[3]Al

The impact of the preliminary load on 3Ni+Al powder mixture and the impact of the duration of the delay in application of compacting pressure to synthesis product under the conditions of continuous heating of the mixture up to its self-ignition on the grain size and strength properties of the synthesized Ni[3]Al intermetallide material have been studied. The grain structure of the intermetallide synthesized under pressure was studied by means of metallography, transmission electron microscopy and EBSD analysis, with the dependence of ultimate tensile strength on the grain size in the synthesized intermetallide having been investigated at room temperature and at temperatures up to 1000°С. It is shown that an increase in the pressure preliminarily applied to the initial mixture compact results in reduced grain size of the final intermetallide, whereas an increase in pre-compaction time makes the grain size increased. A decrease in the grain size increases the ultimate tensile strength of the intermetallide. The maximum value of the ultimate tensile strength in the observed anomalous temperature dependence of this strength exhibits a shift by 200°С toward higher temperatures, and the ultimate strength of the synthesized intermetallide at 1000°С increases roughly two-fold

Adaptive reactions of cardiovascular system of boys with different level of sexual maturity to physical exercise

Graduated physical exercise with the moderate power (50% of PWC170) induces marked change in such cardiovascular system indices as stroke volume and cardiac output, heart rate in boys with the age of 11-16 years. The nature of reactions of the boys' cardiovascular systems rapid adaptation to physical exercise during adolescence period of ontogenesis depends on the level of their sexual maturity. The boys with the 1st and the 2nd grades of sexual maturity demonstrate the reactions to exercise with the highest growth of heart rate, while the highest growth of cardiac output is typical for the boys with the 3-5th grades of sexual maturity. It was revealed that for the boys with the 3-4th sexual maturity stages the reactions to physical activity were expressed in the maximum values of stroke volume and cardiac output and the recovery period for the investigated parameters was rather extended. At this stage of the boys' development the recovery of cardiac output to the level at rest has a non-linear nature, there can be observed a "negative phase" in the heart rate recovery which can be considered as a symptom of excessive response, unfavorable cardiovascular system reaction to physical exercise

Sympathoadrenal system activity of various puberty stages boys

© Medwell Journals, 2016.The catecholamin egestion dynamics analysis and DOFA for teenagers of different sexual maturity level and hormonal and media link becoming of the Sympathoadrenal System (SAS) in the course of boys puberty is carried out. Researches showed that SAS activity for teenagers in the course of puberty changes undulantly. The intensive increase of adrenaline egestion is revealed for boys of 3 puberty stages, the maximal increase of noradrenaline is noted for boys of 4th Puberty Stage (PS) then intensively decreases on 5th PS. Increase in dopamine and DOFA egestion reflect increase of reserve abilities of SAS on 5th puberty stage. Formation of SAS hormonal link for teenage boys happens earlier than that of the medial link: increase of SAS hormonal link activity is noted for boys on 1 -2 PS and decreases on 3-4 PS where activity of SAS medial link is higher. On 5th PS the relative stability of all studied parameters which size during this period comes nearer to definitive level reflecting the relative SAS maturity for boys and particular degree of SAS formation processes completeness within the studied age range takes place

NPY<inf>1</inf> Receptors Participate in the Regulation of Myocardial Contractility in Rats

© 2017, Springer Science+Business Media New York.Selective agonist (Leu(31)Pro(34)NPY) and blocker (BIBP-3226) of NPY1 receptors were used to determine the type of NPY receptors involved in myocardial contraction. Experiments with isometric contraction of myocardial strips from mature rats showed that the agonist produced the most potent effect in a concentration of 10—7 M. In this concentration, Leu(31)Pro(34)NPY showed the greatest positive inotropic effect on the contraction of the atria and ventricles. In contrast, selective blocker BIBP-3226 reduced the force of myocardial contractions. Pretreatment of myocardial strips with this blocker abolished the positive inotropic effect of Leu(31)Pro(34)NPY, which attested to important role of NPY1 receptors in myocardial contraction

HERBARIUM SPECIMENS OF WILD CHILEAN POTATO SPECIES BELONGING TO THE SECTION <i> PETOTA </i> DUMORT. GENUS <i> SOLANUM </i> L. IN THE VIR HERBARIUM

A revision of herbarium specimens of Chilean potato species belonging to the section Petota Dumort. genus Solanum L. was conducted. The VIR herbarium [WIR] has 25 specimen sheets of five species: Solanum leptostigma Juz., S. maglia Schlechtd., S. molinae Juz., S. ochoanum Lechn., S. zykinii Lechn. Authentic materials from S.V. Yuzepczuk and V.S. Lehnovich have been identified, namely syntypes of S. molinae , S. ochoanum and S. zykinii. The neotypification of S. leptostigma was done

Structure and Microhardness of Coatings Fabricated by Non-Vacuum Electron Beam Surfacing of WC Powder on Aluminum Alloy AMg6

The aim of work: to determine the structure and microhardness of WC coatings fabricated by method of non-vacuum electron-beam surfacing onto the AMg6 matrix. The results of measuring the microhardness of coatings showed that its increase occurs by 19-23% compared to the AMg6 matrix.Авторы выражают благодарность Голковскому Михаилу Гедалиевичу (Институт ядерной физики им. Г. И. Будкеpа СО РАН) за оказанную помощь в проведении электронно-лучевой наплавки

Закономерности регенерации конъюнктивы и склеры после интраоперационной аппликации раствора циклоспорина А у кроликов со стероидной моделью глаукомы

 Aim. In an in vivo experiment, to study the effect of local intraoperative application of 0.05% cyclosporin A solution on the conjunctival and scleral regeneration after surgery on the rabbit eyes with steroid-induced  glaucoma.Materials and methods. At the first stage of the experiment, a model of steroid-induced glaucoma was reproduced for 29 male Californian rabbits by injecting 0.5 ml of a 0.4% solution of dexamethasone subconjunctivally in both eyes once a week for 3 months (12 subconjunctival injections for each rabbit). At the second stage of the experiment, after the development of  steroid glaucoma, the rabbits were divided into the main group, consisting  of the subgroup «a» (n = 8) and the subgroup «b» (n = 8), and the comparison group (n = 8). All animals were performed a penetrating incision of the conjunctiva and a non-penetrating incision of the sclera of one of the eyes. A hemostatic sponge impregnated with 0.05% cyclosporin А solution was applied to the intervention area in the main group, in the subgroup «a» – for 3 minutes, in the subgroup «b» – for 6 minutes. In the comparison group, the cytostatic was not used.Results. The use of 0.05% cyclosporin А solution led to a decrease in the  infiltration of fibroblasts and inflammatory cells into the area of surgical  injury. On the 4th day after the surgery, cell density in the intervention area  in the subgroup «a» with 3-minute application of cytostatic-antimetabolite solution was 2.7 times lower (p = 0.043) than in the comparison group, while exceeding the values in the subgroup «b» by 3.2 times (p = 0.036). The number of fibroblasts in the subgroups «a» and «b» was 3.6 (p = 0.043) and 12.8 times (p = 0.031) less than in the comparison group, and a shift in the cellular composition of the infiltrate towards the fibroblastic population occurred only on the 14th day after the surgery.Conclusion. Intraoperative application of 0.05% cyclosporin А solution significantly slows down the course of regeneration, reducing infiltrative inflammation in the intervention area, which prevents excessive scarring.  Цель. В эксперименте in vivo изучить влияние местной интраоперационной аппликации 0,05%-го раствора (р-ра) циклоспорина А на регенерацию конъюнктивы и склеры  после операции на глазах кроликов со стероидной  глаукомой.Материалы и методы. На I этапе эксперимента 29 самцам  кроликов калифорнийской породы моделировали  стероидную глаукому путем введения под конъюнктиву  обоих глаз 0,5 мл 0,4%-го р-ра дексаметазона 1 раз в нед в течение 3 мес (12 инъекций). На II этапе эксперимента, после развития стероидной глаукомы, кроликов разделили на основную группу, состоящую из подгруппы «a» (n = 8) и подгруппы «b» (n = 8), и группу сравнения (n = 8). Всем животным выполняли сквозной разрез конъюнктивы и непроникающий надрез склеры одного из глаз. На область вмешательства в основной группе накладывали гемостатическую губку, пропитанную 0,05%-м р-ром циклоспорина А, в подгруппе «а» на 3 мин, в подгруппе «b» – на 6 мин. В группе сравнения цитостатик не использовали.Результаты. Применение 0,05%-го р-ра циклоспорина А  привело к уменьшению инфильтрации зоны хирургической  травмы воспалительными клетками и фибробластами. На 4- е сут после операции клеточная плотность в области вмешательства в подгруппе «а» основной группы с трехминутной аппликацией р-ра цитостатика-антиметаболита была в 2,7 раза меньше (p = 0,043), чем в  группе сравнения, превышая при этом показатели подгруппы «b» в 3,2 раза (p = 0,036). Численность  фибробластов в подгруппах «а» и «b» была в 3,6 (p = 0,043) и 12,8 раза (p = 0,031) ниже, чем в группе сравнения. При  этом сдвиг клеточного состава инфильтрата в сторону  фибробластической популяции произошел только на 14-е  сут после операции. Заключение. Интраоперационная аппликация 0,05%-го р- ра циклоспорина А существенно замедляет течение  воспалительно-репаративной регенерации, уменьшая  инфильтративное воспаление в зоне вмешательства, что  предотвращает излишнее рубцевание.