The influence of bone substitute material on mechanical properties of trabecular bone in augmentation of intra-articular impression fractures. Experimental study

The purpose was to evaluate the effect of bone substitute materials on mechanical properties of trabecular bone adjacent to the joint. Material and methods A total of 21 female chinchilla rabbits weighing 3-3.5 kg was used for the experimental study. A bilateral impression fracture was simulated in the medial tibial condyle and surgically augmented with one of the bone substitution materials: beta-tricalcium phosphate, xenoplastic material and carbon nanostructures. The animals were sacrificed at 6, 12 and 24 weeks postsurgery. Uniaxial compression test was performed to determine mechanical properties of the tibial fragments. Bone microstructure was evaluated with scanning electron microscopy. Statistical data analysis was performed with nonparametric tests. Results Beta-tricalcium phosphate augmentation of the bone interface led to slow resorption accompanied by formation of adequate high-grade bone tissue with mechanical properties gradually increasing with greater observation time that indicated to the bone substitute integrated well with the host bone of the impression bone defect. Xenoplastic augmentation resulted in rapid resorption accompanied by formation of immature bone with mechanical properties declining at 6 to 12 weeks of observation. Carbon nanostructure augmentation of the bone interface caused perifocal bone resorption and absence of osteointegration with mechanical properties declining at 12 to 25 weeks of observation

Raise the anchor! Synthesis, X-ray and NMR characterization of 1,3,5-triazinanes with an axial tert-butyl group

N-t-Bu-N’,N’’-disulfonamide-1,3,5-triazinanes were synthesized and characterized by X-ray single crystal structure analysis. In the course of the X-ray structure elucidation, the first solid experimental evidence of the axial position of the tert-butyl group in unconstrained hexahydro-1,3,5-triazacyclohexanes was obtained. Dynamic low-temperature NMR analysis allowed to fully investigate a rare case of crystallization-driven unanchoring of the tert-butyl group in the chair conformation of saturated sixmembered cycles. DFT calculations show that the use of explicit solvent molecules is necessary to explain the equatorial position of the t-Bu group in solution. Otherwise, the axial conformer is the thermodynamically stable isomer.Fil: Kletskov, Alexey V.. University of Russia; RusiaFil: Zatykina, Anastasya D.. University of Russia; RusiaFil: Grudova, Mariya V.. University of Russia; RusiaFil: Sinelshchikova, Anna A.. Academy of Sciences; RusiaFil: Grigoriev, Mikhail. Academy of Sciences; RusiaFil: Zaytsev, Vladimir P.. University of Russia; RusiaFil: Gil, Diego Mauricio. Universidad Nacional de Tucumán. Instituto de Biotecnología Farmacéutica y Alimentaria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Biotecnología Farmacéutica y Alimentaria; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química Orgánica; ArgentinaFil: Novikov, Roman A.. Academy of Sciences; RusiaFil: Zubkov, Fedor Ivanovich. University of Russia; RusiaFil: Frontera, Antonio. Universidad de las Islas Baleares; Españ

Intramolecular sp2-sp3 disequalization of chemically identical sulfonamide nitrogen atoms: single crystal X-Ray diffraction characterization, hirshfeld surface analysis and DFT calculations of N-substituted hexahydro-1,3,5-triazines

In this manuscript, the synthesis and single crystal X-ray diffraction characterization of four N-substituted 1,3,5-triazinanes are reported along with a detailed analysis of the noncovalent interactions observed in the solid state architecture to these compounds, focusing on C–H···π and C–H···O H-bonding interactions. These noncovalent contacts have been characterized energetically by using DFT calculations and also by Hirshfeld surface analysis. In addition, the supramolecular assemblies have been characterized using the quantum theory of “atoms-in-molecules” (QTAIM) and molecular electrostatic potential (MEP) calculations. The XRD analysis revealed a never before observed feature of the crystalline structure of some molecules: symmetrically substituted 1,3,5-triazacyclohexanes possess two chemically identical sulfonamide nitrogen atoms in different sp2 and sp3-hybridizations.Fil: Kletskov, Alexey V.. University of Russia; RusiaFil: Gil, Diego Mauricio. Universidad Nacional de Tucumán. Instituto de Biotecnología Farmacéutica y Alimentaria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Biotecnología Farmacéutica y Alimentaria; ArgentinaFil: Frontera, Antonio. Universidad de las Islas Baleares; EspañaFil: Zaytsev, Vladimir P.. University of Russia; RusiaFil: Merkulova, Natalia L.. University of Russia; RusiaFil: Beltsova, Ksenia R.. University of Russia; RusiaFil: Sinelshchikova, Anna A.. University of Russia; RusiaFil: Grigoriev, Mikhail S.. University of Russia; RusiaFil: Grudova, Mariya V.. University of Russia; RusiaFil: Zubkov, Fedor I.. University of Russia; Rusi

Tunable THz flat zone plate based on stretchable single-walled carbon nanotube thin film

Tunable optoelectronics have attracted a lot of attention in recent years because of their variety of applications in next-generation devices. Among the potential uses for tuning optical elements, those allowing consistent parameter control stand out. We present an approach for the creation of mechanically tunable zone plate lenses in the THz range. Our devices comprise single-walled carbon nanotube (SWCNT) thin films of predetermined design integrated with stretchable polymer films. These offer high-performance and in situ tunability of focal length up to 50%. We studied the focusing properties of our lenses using the backward-wave oscillator THz imaging technique, supported by numerical simulations based on the finite element frequency domain method. Our approach may further enable the integration of SWCNT films into photonic and optoelectronic applications and could be of use for the creation of a variety of flexible and stretchable THz optical elements

Разработка технологии переработки упорных золотосодержащих концентратов на покровском автоклавно-гидрометаллургическом комплексе

The chemical composition and mineralogy of Malomir and Pioneer gold-bearing ores were discussed. The main gold forms in the ores were indicated: the preferential gold association with sulfide minerals was noted. The chemical composition of sulfide flotation concentrates was shown. The laboratory and pilot tests results of concentrates pressure oxidation were introduced. The influence of organic carbon content in the concentrate and chloride ion content in the liquid phase of pressure oxidation slurry on the gold extraction from materials were noted and researched. The effect of preliminary treatment stages on POX indicators was shown. The positive effect of hot autoclave slurry conditioning on gold recovery was noted. The process flow sheet for treating both Malomir and Pioneer ores was developed and advisedРассмотрен химический состав и минералогия маломирских и пионерских золотоносных руд. Указаны основные формы золота в рудах: отмечено преимущественное соединение золота с сульфидными минералами. Показан химический состав сульфидных флотационных концентратов. Представлены результаты лабораторных и полупромышленных испытаний окисления концентратов под давлением. Отмечено и исследовано влияние содержания органического углерода в концентратах и содержания ионов хлорида в жидкой фазе суспензии окисления под давлением на извлечение золота из материалов. Показано влияние предварительных стадий обработки по показателям технологии автоклавного окисления. Отмечено положительное влияние обработки горячей автоклавной суспензией на извлечение золота. Разработана и рекомендована технологическая схема процесса обработки маломирских и пионерских ру

Colloidal suspensions in external rotating electric field: experimental studies and prospective applications in physics, material science, and biomedicine

Colloidal suspensions and tunable self-assembly of colloidal particles attract a great interest in recent years. In this paper, we propose a new setup and technology for studies of self-assembly of colloidal particles, interection of which between themselves is tuned by external rotating electric fields. We reveal wide prospectives of electric field employment for tunable self-assembly, from suspensions of inorganic particles to ensembles of biological cells. These results make enable particle-resolved studies of various collective phenomena and fundamental processes in many-particle systems in equilibrium state and far from it, while the dynamics can be resolved at the level of individual particles using video microscopy. For the first time, we demonstrate that, apart from ability to prepare photonic crystalline films of inorganic silica particles, the tunable self-assembly provides a novel technological way for manipulation with ensembles of biological cells by control of interactions between them

Nucleophilic Ring Opening of Donor–Acceptor Cyclopropanes with the Cyanate Ion: Access to Spiro[pyrrolidone-3,3′-oxindoles]

The nucleophilic ring opening of donor–acceptor cyclopropanes with the cyanate ion is reported for the first time. Cyclopropanes, spiro-activated with oxindole fragments as acceptors, are shown to undergo transformations into biologically relevant spiro­[pyrrolidone-3,3′-oxindoles] while being treated with potassium cyanate under microwave assistance

Разработка технологии переработки упорных золотосодержащих концентратов на покровском автоклавно-гидрометаллургическом комплексе

The chemical composition and mineralogy of Malomir and Pioneer gold-bearing ores were discussed. The main gold forms in the ores were indicated: the preferential gold association with sulfide minerals was noted. The chemical composition of sulfide flotation concentrates was shown. The laboratory and pilot tests results of concentrates pressure oxidation were introduced. The influence of organic carbon content in the concentrate and chloride ion content in the liquid phase of pressure oxidation slurry on the gold extraction from materials were noted and researched. The effect of preliminary treatment stages on POX indicators was shown. The positive effect of hot autoclave slurry conditioning on gold recovery was noted. The process flow sheet for treating both Malomir and Pioneer ores was developed and advisedРассмотрен химический состав и минералогия маломирских и пионерских золотоносных руд. Указаны основные формы золота в рудах: отмечено преимущественное соединение золота с сульфидными минералами. Показан химический состав сульфидных флотационных концентратов. Представлены результаты лабораторных и полупромышленных испытаний окисления концентратов под давлением. Отмечено и исследовано влияние содержания органического углерода в концентратах и содержания ионов хлорида в жидкой фазе суспензии окисления под давлением на извлечение золота из материалов. Показано влияние предварительных стадий обработки по показателям технологии автоклавного окисления. Отмечено положительное влияние обработки горячей автоклавной суспензией на извлечение золота. Разработана и рекомендована технологическая схема процесса обработки маломирских и пионерских ру