The problem of replacement of large bone defects resulting from segmental bone resections in patients with bone tumors is still actual in modern orthopedics. Segmental defects cause the main difficulty especially in cases of disturbance of normal biomechanics while the “gold standard” of reconstruction with bone autograft is not always possible. The reason is that the defect can be so extensive that would make it impossible to harvest necessary autobone stock. Therefore, allografts based on demineralized bone with optimal properties for osteoregeneration are used as an alternative for autograft. For certain composite materials it is possible to program the properties of future graft by changing its compound. Literature analysis revealed that the effectiveness of the allograft in combination with additional components is comparable to autograft effectiveness. Mesenchymal stem cells of both bone marrow and adipose tissue can be used as an additional component to improve osteoregeneration. It is noteworthy that the analyzed studies did not reveal the influence of stem cells on the tumor recurrence. Nevertheless, the authors support the need of further researches in this area to confirm gained results. Some authors still prefer traditional methods of bone traction despite obtaining own satisfactory results of defects reconstruction with allografts. Such opinion is based on proven effectiveness of the method, structural stability of construction during treatment period and ability to adjust the process of bone regeneration at any stage. The authors goal was to analyze publications over the recent 5 years with the results of experiments and clinical studies on the replacement of large bone defects after bone tumor resection with autoand allografts. Based on the literature analysis the authors propose a general algorithm for graft selection in replacement of large bone defects after segmental bone resections.

Изменение численности эколого-трофических групп микроорганизмов в разных технологиях возделывания озимой пшеницы РЕЗЮМЕАктуальность и методика. Протекающие в почве процессы микробиологического превращения вещества тесно связаны с продуктивностью сельскохозяйственных культур, влияя на рост и питание растений. Приведены данные по численности почвенных дрожжей и микроорганизмов, трансформирующих соединения азота в зависимости от технологии возделывания озимой пшеницы. Численность микроорганизмов, трансформирующих соединения азота, выше в технологии без обработки почвы (no-till).Результаты. Установлено, что внесение аммиачной селитры N 52 приводит к существенному увеличению численности микроорганизмов в технологии с мелкой обработкой почвы (от 28,5 до 31,3•10 5 КОЕ/г АСП). На вариантах с внесением минеральных удобрений численность микроорганизмов увеличивалась на всех технологиях возделывания озимой пшеницы. Наибольшая численность микроорганизмов отмечена на вариантах с внесением полного минерального удобрения, в среднем по годам исследования и технологиям возделывания она составила для микроорганизмов, трансформирующих соединения азота, -154,2•10 5 КОЕ/г АСП и для почвенных дрожжей -44,9•10 3 КОЕ/г АСП. За период исследований отзывчивость озимой пшеницы на удобрения была очень высокой. Максимальная урожайность культуры достигнута на варианте с внесением N 52 P 52 K 52 -5,32-7,02 т/га. Применение минеральных удобрений способствовало созданию благоприятных условий для развития почвенной микрофлоры, что оказало положительное влияние на урожайность озимой пшеницы. Change in the number of ecological-trophic groups of microorganisms in different technologies of winter wheat cultivation ABSTRACTRelevance and methods. The processes of microbiological transformation of substances in soil are closely related to the productivity of crops, affecting the growth and nutrition of plants. Data are given on the number of soil yeast and microorganisms transforming nitrogen compounds depending on the technology of winter wheat cultivation. The number of microorganisms transforming nitrogen compounds is higher in the technology without soil treatment (no-till).Results. It was established that the introduction of ammonium nitrate N 52 leads to a significant increase in the number of microorganisms in technology with fine soil treatment (from 28.5 to 31.3•10 5 colonies forming units per gram of absolutely dry soil). In versions with the introduction of mineral fertilizers, the number of microorganisms increased on all technologies for cultivating winter wheat. The largest number of microorganisms was noted on versions with the introduction of complete mineral fertilizer, on average by the years of study and cultivation technologies, it was for microorganisms that transform nitrogen compounds -154.2•10 5 colonies forming units per gram of absolutely dry soil and for soil yeast -44.9•10 3 colonies forming units per gram of absolutely dry soil. During the period of research, the responsiveness of winter wheat to fertilizers was very high. M...

Purpose: to study the influence of methods and rates of mineral fertilizers on the winter wheat yield and grain quality by direct sowing on corn on ordinary chernozem under conditions of unstable moisture in Stavropol Territory. Materials and methods. The studies were carried out in 2014–2019 in a three-factor experiment in the fields of the North Caucasus Federal Scientific Agrarian Center. We studied the effect of pre-sowing fertilization and nitrogen fertilization (N52) on wheat productivity with two tillage technologies: with the recommended tillage system and with direct sowing (No-Till). Pre-sowing fertilization options: 1) without fertilizers; 2) N6P26; 3) N12P52; 4) N24P104; 5) N52P52; 6) N52P52K52; 7) N52; 8) N104P52K52. Results. Direct sowing had an advantage over the recommended technology in the reserves of productive moisture in the soil layer of 0–100 cm during the sowing period. In the No-Till technology, the average yield increase from pre-sowing fertilizer was within 0.78–3.02 t/ha (28–109 %), from nitrogen fertilization it was 0.55–1.85 t/ha (15–48 %) and when both methods of application are combined – 1.47–4.02 t/ha (53–145 %). The highest and most stable increments over the years (3.07–4.56 t/ha, or 101–219 % to the control) were obtained when using the maximum rate of pre-sowing fertilizer with nitrogen fertilization – N104P52K52 + N52. The increase in grain yield per unit of active fertilizer substance was 15.5 kg. Mass fraction of crude gluten in grain exceeded the control by 3.0–7.9 %. The application of this fertilizer dose helped to equalize the yield between technologies. Conclusions. The results showed that in order to obtain the greatest agronomic effect in the third year of direct sowing of winter wheat on maize, the predominant application of nitrogen fertilizer in a total dose exceeding the dose of phosphorus and potassium by 2–3 times is required. Correctly selected methods of application and fertilizers rates prevent a decrease in wheat yield when switching from the recommended tillage technology to direct sowing.

Problems related to rare earth metals leaching from coal ash and theirs ion-exchange concentration from sulfuric solutions, in particular the characteristics of scandium, yttrium and lanthanum sorption by different ion exchange resins have been considered in this work. It has been shown that the best way to leach rare earth metals from coal ash is a complex acid and biological treatment of ash waste. Kinetics related to the process of scandium, yttrium and lanthanum acid leaching from ash and slag waste of CHPP in Kumertau has been investigated. Subsequent metal solutions concentration was achieved using ion exchange resins. The results of experimental studies related to the processes of rare-earth metals (in particularly scandium) ion exchange concentration by cation exchange resin in the Naform PC-100 have been presented, as well as the results of experimental studies related to rare earth metals (scandium including) sedimentation process, using special sedimentators. Dependences of rare earth metals (in particular scandium) sedimentation efficiency against pH value have been constructed, and recommendations for pH values, that are optimal for rare earth metals sedimentation, have been given. Based on obtained experimental results it was created and tested an experimental laboratory prototype of plant for rare earth metals (scandium, yttrium and lanthanum including) extraction from located near Moscow brown coal basin’s slag heaps, and from ash dumps of Russian Federation’s energy enterprises. This plant’s process flow diagram as well as its operation description has been presented. The created plant was tested in modes previously fulfilled in laboratory conditions. At the same time, carried out integrated exploration have showed the prospects for implementation of developed technical solutions for processing of ash dumps of Russian Federation’s various energy enterprises.