The preparation of the Ti-Al alloys based on intermetallic phases

This article deals with a method of obtaining materials in the Ti-Al system. Research was carried out in accordance with the phase diagram of the system state. It was established, that both single-phase and multiphase systems, containing finely dispersed intermetallic compositions of phases Ti3Al, TiAl and TiAl3, are formed. Additionally, it was found that the pure finely dispersed (coherent-scattering region (CSR) up to 100 nm) intermetallic compound TiAl3 is formed at molar ratio of Ti:Al = 1:3. Experimentally proved the possibility of produce the complex composition of alloys and intermetallic compounds and products based on them

The Birth and Death of Toxins with Distinct Functions: A Case Study in the Sea Anemone Nematostella

The cnidarian Nematostella vectensis has become an established lab model, providing unique opportunities for venom evolution research. The Nematostella venom system is multimodal: involving both nematocytes and ectodermal gland cells, which produce a toxin mixture whose composition changes throughout the life cycle. Additionally, their modes of interaction with predators and prey vary between eggs, larvae, and adults, which is likely shaped by the dynamics of the venom system. Nv1 is a major component of adult venom, with activity against arthropods (through specific inhibition of sodium channel inactivation) and fish. Nv1 is encoded by a cluster of at least 12 nearly identical genes that were proposed to be undergoing concerted evolution. Surprisingly, we found that Nematostella venom includes several Nv1 paralogs escaping a pattern of general concerted evolution, despite belonging to the Nv1-like family. Here, we show two of these new toxins, Nv4 and Nv5, are lethal for zebrafish larvae but harmless to arthropods, unlike Nv1. Furthermore, unlike Nv1, the newly identified toxins are expressed in early life stages. Using transgenesis and immunostaining, we demonstrate that Nv4 and Nv5 are localized to ectodermal gland cells in larvae. The evolution of Nv4 and Nv5 can be described either as neofunctionalization or as subfunctionalization. Additionally, the Nv1-like family includes several pseudogenes being an example of nonfunctionalization and venom evolution through birth-and-death mechanism. Our findings reveal the evolutionary history for a toxin radiation and point toward the ecological function of the novel toxins constituting a complex cnidarian venom.publishedVersio

Corrosion resistance of neodymium and dysprosium hydrides

This paper describes the methods of obtaining hydrides of rare earth elements such as dysprosium and neodymium. The properties and corrosion resistance of these elements are investigated. A synthesis method of monophasic dysprosium and neodymium dihydrides is presented. Synthesized dihydrides are agglomerates with an average size of 3-50 µm and are formed by crystalline grains of a nanometer size. BET specific surface area, morphology, elemental analyses and composition of samples have been studied. Corrosion stability in aqueous solutions of hydrochloric acid and sodium hydroxide were studied. It was determined that both hydrides undergo hydrolysis in acid and alkaline mediums. Neodymium hydride is more stable to corrosion than dysprosium hydride, which is proved by its longer exposure to aggressive medium to hydrides. The formation of insoluble /poorly soluble products of corrosion can make a significant contribution to the process of powder dissolution

ПОВЫШЕНИЕ ТРЕЩИНОСТОЙКОСТИ АСФАЛЬТОБЕТОННЫХ ПОКРЫТИЙ

The methods used toincrease temperature resistance of bituminous concrete pavement are in the focus of researches in the sphere of road engineering which study first of all the bituminous concrete mixtures with polymer modified cementing bitumen. But the most common polymers of styrene-butadiene-styrene type, like DST-30–01, Kraton, Lupren LG, considerablyincrease costs of highways construction. That’s why the researchers have restarted study on possible use of the waist of tyre manufacturing as modifier.The study refers to the powder of discretely devulcanized rubber which serves as modifier under the name of Unirem.The authors’ technology permits to manufacture polymer astringent bitumen.Evaluation of low temperature properties of such material were conducted during typical testing according to AASHTO TP1 standard that figures on the list of specifications «Superpave».The tests revealed the data on crack resistance of rubber-bitumen cementing component of highways. A new method of analysis of deformation of cementing properties under low temperature and v aried speed of reconstruction of lost properties is proposed. The results of “dry” and “wet” modes for the initial and modified bitumen components are compared.Bringing in of rubber granules by “dry” mode doesn’t ensure stability of the properties of bituminous concrete pavement. While the introduction of the rubber granules into bitumen and concrete mixture together with rubber-bitumen cementing component positively affects crack growth resistance and reduces the total costs of highway construction.В статье представлены данные по трещиностойкости резинобитумного вяжущего компонента автодорожных покрытий. Предложен метод исследования характера деформаций вяжущих свойств при отрицательных температурах и разных скоростях восстановления потерянных качеств. Приведены результаты применения «сухого» и «мокрого» способов для исходного и модифицированного битумных компонентов. Показано, что введение резиновой крошки «сухим способом» не гарантирует стабильности свойств асфальтобетонного покрытия в период эксплуатации. В то же время наличие такой крошки в составе резинобитумного вяжущего компонента дает возможность заметно повысить трещиностойкость асфальтобетонного покрытия

SHS for Space Exploration

For over past years, interest of leading space agencies (NASA, JAXA, ESA, RSA, etc.) in SHS experiments under microgravity conditions has been increasingly growing. The first SHS experiments during a parabolic flight in Russia and aboard the MIR Space station gave promising results. Similar studies are now being carried out in various countries. The obtained data and assimilated experience have shown that SHS reactions can be used for (a) synthesis of high-porosity materials and regulation of structure formation in combustion products, (b) preparation of skeleton structures by combustion of particles suspended in vacuum, (c) generation of thermal energy, (d) generation of incandescent radiation, and (e) for in-space fabrication and in-situ repair works (welding, joining, cutting, coating, near-net-shape production, etc.). However, the results of the above studies (strongly scattered in the literature) still seem insufficient for elucidating the mechanism of combustion in. Indeed, the experiments were carried out by different researchers for a dozen of systems and for strongly different duration of microgravity (drop towers, parabolic flight of a plane, parabolic flight of a spacecraft, in space stations). No correlation has been made with the available data of SHS studies (oriented largely on practical implementation) in conditions of artificial gravity. In experiments, the combustion wave has enough time to spread over the sample while the structure formation, may not have. This implies that the process of wave propagation should always be identical, irrespective of the type of experimental technique and place of experiment. SHS experiments in space are attractive because (a) of low energy requirements, (b) processing cycle is short, (c) of process simplicity, (d) of versatility (wide range of suitable materials, and (e) the use of in-situ resources possible. To date, SHS experiments has already been performed aboard the International Space Station (ISS). Space technology has been developed for frontier exploration not only around the Earth orbit environment but also to the Moon, Mars, etc

Hydride-dehydride fine zirconium powders for pyrotechnics

In this paper, the possibility of obtaining fine zirconium powders by the hydrogenationdehydrogenation method is studied. The main parameters of the technological process that allow obtaining fine zirconium powders for pyrotechnics are determined. Hydrogenation and dehydrogenation of the samples are carried out in a rotating quartz tube placed in a furnace at temperatures of 380◦C and 850◦C, respectively. Zirconium hydride is milled using tungsten carbide balls to eliminate the presence of impurities. Thus it is possible to obtain a fine zirconium powder with a number-average particle size of 4.527 +- 2.650 Um and a specific surface area of 0.231 m2/g from the initial electrolytic zirconium powder with a number-average particle size of 220 Um and a specific surface area < 0.1 m2/g. The allowed relative error of measuring the specific surface area is +- 5%. Hence it is possible to reduce the particle size of zirconium powder by 54.6 times without changing the composition

Electric Conductivity and Gas-Sensing Properties of Nickel Ferrite Thin Films Formed by Ion-Beam Sputtering Deposition

Ferrites with composition of NiMnxFe1-xO4, (with x = 0 ÷ 1.0) have been synthesized by self-propagating high-temperature synthesis (SHS). The particle size of the synthesized ferrite powder was about 10 nm. Additional heat treatment at 1270 K during 50 min allowed us to obtained product with the single phase composition NiFe2O4.  We found out that the increasing of the manganese content (x) increased the lattice constant of the ferrites from 0.833896 nm (x = 0) up to 0.836369 nm (x = 1). The synthesized powder contains two types of ferrite particles that are varied in size and shape. The magnetic properties significantly depend on the microstructure and chemical composition of synthesized ferrites. It has been found that the coercive force Hc increased from 1.75 (x = 0.2) to 2.85 (x = 1). By using of IBSD technology thin film of NiFe2O4 was sputtered on the Si (100) substrate. All sputtered films were X-ray transparent. The structure of ferrite films consisted of agglomerate less than 35 nm. The thickness of the sputtered film was about 600 nm. Additional heat treatment at 770 K during 90 min resulted to homogeneity of the film microstructure. The temperature range 400-750 K corresponds to working temperature range of gas-sensing devices. The ferrite compounds were studied by TOF-SIMS (Time-of-Flight Secondary-Ion-Mass-Spectrometry) for all depth of film. The resistivity R of synthesized film was 39 kΩ. Measurement of gas-sensing sensitivity RCH4/Rair for gas (2%v. CH4) – air mixture showed increase of R up to 12% at the present of methane at 403 K. For further research we plan to replace iron to manganese ions in chemical compounds of ferrite

Концентрация мочевой кислоты и показатели липопероксидации клеточных мембран при дыхательной гипоксии у детей с острыми бронхолегочными заболеваниями

A comparative analysis of uric acid level in children with acute bronchopulmonary diseases (80 pneumonic and 65 bronchitis patients) revealed a clear correlation between its concentration and a respiratory failure severity, and a hypoxaemia level as well. This fact confirms a role of hypoxia in purine nucleotides catabolism, resulting in uric acid production. The relation established between a uric acid concentration and lipid peroxidation products content proved the role of purine metabolism acute disorders in a lipid peroxidation enhancement caused by a xanthinoxidase activation that had been shown experimentally. An application of metronidazole as a xanthinoxidase inhibitor in severe pneumonia and Riboxine as a source of inosine in obstructive bronchitis with severe respiratory disorders led to shortening of a dyspnoe period and of length of stay in an intensive care unit and also facilitated an inhibition of excessive lipid peroxidation of cell membranes.Сравнительный анализ уровня мочевой кислоты у детей с острыми бронхолегочными заболеваниями (80 с пневмонией и 65 с бронхитом) показал четкую зависимость ее концентрации от степени дыхательной недостаточности и уровня гипоксемии, что явилось подтверждением роли гипоксии в катаболизме пуриновых нуклеотидов, конечным продуктом которого и является мочевая кислота. Установленная связь между концентрацией мочевой кислоты и содержанием продуктов липопероксидации подтвердила доказанную в эксперименте роль нарушения пуринового обмена в усилении опосредованного активацией ксантиноксидазы, перекисного окисления липидов. Применение метронидазола, как ингибитора ксантиноксидазы при тяжелых формах пневмонии и рибоксина, как источника инозина, при обструктивных формах бронхита с тяжелыми дыхательными расстройствами сокращало период одышки, время нахождения пациентов в отделении реанимации и способствовало торможению чрезмерной липопероксидации клеточных мембран

Microbiological landscape of periodontal pockets in patients with chronic generalized periodontitis on a background of application of photodynamic therapy with gel laminarii saccharine

Presents results of a survey of 200 patients suffering from chronic generalized periodontitis of moderate severity. The characteristic clinical features of these patients. Conducted microbiological assessment of the contents of periodontal pocket. Deals with diagnosis and treatment of patients with chronic generalized periodontitis with photodynamic therapy with gel, Lamifnarii saccharine. Determined the effectiveness of treatment.Представлены результаты обследования 200 пациентов, страдающих хроническим генерализованным пародонтитом средней степени тяжести. Дана характеристика клиническим, функциональным особенностям этих больных. Проведена микробиологическая оценка содержимого пародонтального кармана. Рассмотрены вопросы диагностики и лечения пациентов хроническим генерализованным пародонтитом с применением фотодинамической терапии с гелем на основе Ламинарии сахаристой. Определена эффективность лечения

Development and external validation of a clinical prediction model for functional impairment after intracranial tumor surgery

OBJECTIVE Decision-making for intracranial tumor surgery requires balancing the oncological benefit against the risk for resection-related impairment. Risk estimates are commonly based on subjective experience and generalized num-bers from the literature, but even experienced surgeons overestimate functional outcome after surgery. Today, there is no reliable and objective way to preoperatively predict an individual patient's risk of experiencing any functional impair-ment. METHODS The authors developed a prediction model for functional impairment at 3 to 6 months after microsurgical resection, defined as a decrease in Karnofsky Performance Status of >= 10 points. Two prospective registries in Swit- zerland and Italy were used for development. External validation was performed in 7 cohorts from Sweden, Norway, Germany, Austria, and the Netherlands. Age, sex, prior surgery, tumor histology and maximum diameter, expected major brain vessel or cranial nerve manipulation, resection in eloquent areas and the posterior fossa, and surgical approach were recorded. Discrimination and calibration metrics were evaluated. RESULTS In the development (2437 patients, 48.2% male; mean age +/- SD: 55 +/- 15 years) and external validation (2427 patients, 42.4% male; mean age +/- SD: 58 +/- 13 years) cohorts, functional impairment rates were 21.5% and 28.5%, respectively. In the development cohort, area under the curve (AUC) values of 0.72 (95% CI 0.69-0.74) were observed. In the pooled external validation cohort, the AUC was 0.72 (95% CI 0.69-0.74), confirming generalizability. Calibration plots indicated fair calibration in both cohorts. The tool has been incorporated into a web-based application available at https://neurosurgery.shinyapps.io/impairment/. CONCLUSIONS Functional impairment after intracranial tumor surgery remains extraordinarily difficult to predict, al- though machine learning can help quantify risk. This externally validated prediction tool can serve as the basis for case by-case discussions and risk-to-benefit estimation of surgical treatment in the individual patient.Scientific Assessment and Innovation in Neurosurgical Treatment Strategie