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The purpose of the work is to establish the possibility of obtaining expanded graphite of high purity (carbon content more than 99.5 % wt.) from flotation-enriched graphite (carbon content 94–97 % wt.) by combining into one process intercalation of graphite with a solution of potassium dichromate in concentrated sulfuric acid with subsequent hydrolysis, and chemical purification using solutions of ammonium bifluoride in sulfuric or hydrochloric acid and Trilon B in an alkaline buffer as purification reagents, and to confirm this possibility by quantum chemical calculations. It has been experimentally shown that combining oxidized graphite synthesis and its chemical purification into one process allows obtaining expanded graphite of high purity, with a carbon content of 99.75–99.85 % wt. The methods of X-ray diffraction and thermogravimetry show that the interaction of oxidized graphite (the residual compound of intercalation of graphite with sulfuric acid) with cleaning reagents does not reduce the ability to expand. The magnitude of the mass loss of oxidized graphite according to various variants of chemical post-cleaning and the temperature range of such loss remain practically unchanged. Quantum chemical calculations of the adsorption energy (∆Eads) of one molecule of Trilon B on the surface of a graphene-like plane (GLP), the complexation reaction of metal sulfates, the energy effect of the interaction of Trilon B with sulfates of alkaline earth metals in an aqueous solution, and with the participation of the surface of the graphene plane were carried out using the GAMESS (US) program by the density functional theory (DFT) method with the B3LYP functional and the 6-31G(d,p) basis set, taking into account the Grimme D3 dispersion correction within the PCM polarizable continuum. The results of the analysis of quantum chemical calculations indicate that the Trilon B molecule is better physically sorbed on the oxidized GLP (–412 kJ/mol) than on its native form (–188 kJ/mol). The values of the energy effect of the complexation of magnesium and calcium cations with Trilon B have a negative value both in an aqueous solution and in the presence of the oxidized form of GLP. This indicates the thermodynamic probability of this process, which is consistent with the experimental results. Regardless of the nature of the cation, its interaction with Trilon B is thermodynamically more likely in an aqueous solution than in the adsorbed state on the surface of oxidized GLP. [ABSTRACT FROM AUTHOR]

The aim of the current study was to find changes in the structure and state of the surface of graphene oxide (GO) under the conditions of its reduction and modification by hetero atoms of nitrogen and amino acids. Reduction of GO was performed with hydrazine hydrate (R-GO), doping with nitrogen atoms - urea impregnation and subsequent heat treatment (N-GO), and the surface of GO was modified with sulfur-containing amino acid – L-cysteine by nucleophilic addition (L-GO). The samples obtained were characterized by analytical methods, such as Raman scattering, IR spectroscopy, TPD-mass-spectrometry, dynamic light scattering spectroscopy. The available Raman spectra indicate a defective structure of GO, reduction of GO leads to greater ordering of the structure in relation to GO, nitrating and modification by amino acid - to the opposite effect, a slight deterioration of the structural state. According to the results of IR spectroscopy, also confirmed by TPD-MS, GO has a large number of functional surface groups: (OH), (C=O), (C=C), (C-O-C), (CO-O-CO), (CH). Hydrazine reduction completely hydrophobizes the surface, in the IR spectra there is only a peak at ~ 1040 cm–1, which corresponds to CO-O-CO vibrations, with significantly reduced intensity, as well as bands at 2120 and 2300 cm–1, which indicate the aromatic nature of the samples and exist in all GO derivatives. In nitrogen and sulfur-containing samples (L-GO) a new peak of ~ 1520 cm–1appears, which corresponds to N-H vibrations in amines. Sulfur-containing derivatives have valence vibrations at 600 cm–1, which most likely corresponds to S-H bonds. Thus, modification of GO leads to a significant change in its structure and surface chemistry, which in turn affects the capability of the obtained samples to capture free radicals. Previous empirical studies have shown that this property increases in the series L-GO > GO > N-GO > R-GO. [ABSTRACT FROM AUTHOR]

Mechanical alloying of the elemental powder mixture of nickel-multiwalled carbon nanotubes (Ni-CNT) and nickel-spectroscopic grade graphite (Ni-SGG) is performed in a high energy planetary ball mill under the same technological modes. Nanocrystalline NiCx carbide (x = 0.3-0.4) synthesized is examined by X-ray diffraction methods (phase and structural analysis, determination of the real structure parameters, etc.). The carbides synthesized are ferromagnets, the coercive force of which (Hc = 6-12 kA/m) depends on the amount of interstitial carbon atoms in octahedral voids of Ni crystal lattice. It is shown that an allotropic form of carbon (SGG or CNT) used at mechanical alloying effects the charge components interaction as well as the crystal structure and properties of final synthesis products. [ABSTRACT FROM AUTHOR]

The magnetic characteristics of thin films in massive samples are considered and realized in present paper. Multilayer nanocomposite materials from both iron and copper powders, and iron powders with multilayer carbon nanotubes were obtained in two ways. The first method is that a mixture of heterogeneous metal powders with the size of 4-100 microns was rolled, sintered and compressed with a total 99% reduction. In a second method, the powders mixtures were previously treated in a planetary mill before sintering. It is shown that the microstructure of the samples obtained is, as a rule, layered. Due to deformation, in particular, rolling, the thickness of the layers can be reduced to nanoscale. The properties of such massive materials, despite the possible heterogeneity of the continuity of the layers during rolling to nanoscale thicknesses and their fragmentation into nanoflakes, are similar in most to the properties of thin films. The relation between the microstructure, which is determined by the method of processing the powders mixture, the thickness of the layers/scales and the coercive force of the obtained materials, is established. The optimal processing parameters are determined for the realization of practically attractive magnetic characteristics of such materials. [ABSTRACT FROM AUTHOR]

Urgency of the research. Pipeline transport (PT) in Ukraine is a basic bar of the oil-and-gas complex of country, guarantee of its energetic safety. It is explained by very important role of the oil-and-gas transport system in the economy of Ukraine. Target setting. Therefore it is necessary to develop the scientific-methodological foundations of ecomanagement of the PT on increasing its technogenous-ecological safety level as the efficient factor of economics greening. Actual scientific researches and issues analysis. For the analyzed works O. M. Adamenko, S. I. Doroguntsova, L. G. Melnika, G. I. Rudko, V. M. Schmandija, D. R. Baer, R. D. Cane a.o. appear a limitness of the date on the theoretical and methodological foundations and the scientific principles of the formation of ecological-economical safety of the PT, the prevention of the risks of technogenous accidents with the high economical and ecological damages. Uninvestigated parts of general matters defining. The scientists have not jet sufficiently developed questions of the integrated estimation and prediction of the technogenous influence on the ecological-economical safety of the PT and its prevention. The research objective. The aim and tasks of the work – to develop the scientific principles of solving the problem of providing and managing of the ecological-economic safety of the PT by improving the technological processes on the base of the integrated estimation of the eco-desctructive technogenous influence on the PT. The statement of basic materials. The article proves the expendiency of an improving of the technological processes, with the high technical-economical and social-ecological efficiency, for the security of the ecological-economical safety (the innovating resource and energy-saving technologies of welding, the synergist protection compositions on the secondary raw materials etc.). The models of complex ecomanagement, monitoring, with receiving the positive synergist ecologicaleconomical effect (PSEE) are developed. Conclusions: it is showed, that the greeneng of economics, the balanced natural using: a prevention of the man-made disasters, the elimination of losses of energetic materials, unreceived products, a compensating expenses on a liquidation of the consequences of technogenous accidents is provided by the improvement of ecomanagement of the technological processes. [ABSTRACT FROM AUTHOR]

Methionine dependence of malignant cells is one of the cancer hallmarks. It is well described that methionine deprivation drives cancer cells death, both in vitro and in vivo. Methionine gamma-lyase (MGL) isolated from different species or obtained by genetic engineering can be used for effective methionine depletion. In this work, we show that MGL S3, a genetically engineered protein comprised of MGL from Clostridium sporogenesis fused to epidermal growth factor (EGF)-like peptide, reduces, in vitro, the number of cancer cells of four different origins-neuroblastoma, lung, breast, and colon cancer. We reveal that MGL S3 is more toxic for neuroblastoma SH-SY5Y and lung cancer H1299 cells compared to MGL tetani, and causes cell death by the induction of apoptosis. In addition, the observed death of cells treated with MGL S3 is accompanied by the prominent downregulation of ERK activity. By the analysis of transcriptomic data of more than 1500 cancer cell lines and patient samples, we show that the high expression of four genes from the methionine metabolism pathway ( AHCY , CBS , DNMT3A , and MTAP ) is associated with poor prognosis for breast cancer and neuroblastoma patients. Additionally, cells of these origins are characterized by a high correlation between EGFR dependency and DNMT3A / CBS expression. Finally, we demonstrate the ability of MGL S3 to enhance the sensitivity of H1299 cells to EGFR inhibition with gefitinib.

The acquired resistance of neuroblastoma (NB) and leukemia cells to anticancer therapy remains the major challenge in the treatment of patients with these diseases. Although targeted therapy, such as receptor tyrosine kinase (RTK) inhibitors, has been introduced into clinical practice, its efficacy is limited to patients harboring mutant kinases. Through the analysis of transcriptomic data of 701 leukemia and NB patient samples and cell lines, we revealed that the expression of RTK, such as KIT, FLT3, AXL, FGFR3, and NTRK1, is linked with HDAC class I. Although HDAC inhibitors have antitumor activity, they also have high whole-body toxicity. We developed a novel belinostat derivative named hydrazostat, which targets HDAC class I with limited off-target effects. We compared the toxicity of these drugs within the panel of leukemia and NB cell lines. Next, we revealed that HDAC inhibition with hydrazostat reactivates NTRK1 , FGFR3 , ROR2 , KIT , and FLT3 expression. Based on this finding, we tested the efficacy of hydrazostat in combination with RTK inhibitor imatinib. Additionally, we show the ability of hydrazostat to enhance venetoclax-induced apoptosis. Thus, we reveal the connection between HDACs and RTK and describe a useful strategy to overcome the complications of single-agent therapies.

Micro/nanosized carbon materials were prepared by electrochemical exfoliation method in the forms of the colloids and thin films. Scanning electronic microscopy, optical and luminescent microscopy, and Raman scattering and luminescent spectroscopy were applied for characterization of materials. The wide photoluminescence band in the visible spectral region was observed for each of the samples. The shape of the photoluminescence band depends on excitation wavelength and on the size of the particles. At least two components with maxima at ~580 and ~710 nm can be distinguished in the photoluminescence spectra. The relations between the photoluminescence properties and morphology of the samples have been described and discussed.

Nanocomposite materials of the Fe-Cu system with/without small addition of carbon nanotubes have been synthesized by mechanochemical activation of elemental Fe and Cu powders in a high-energy planetary ball mill and have been examined by the X-ray diffraction method, SEM and the thermopower methods; the tensile strength of the materials obtained has been estimated. The metastable (Fe, Cu) supersaturated solid solution is formed in the Fe-Cu nanocomposites during milling process. The coherent scattering block size of the materials obtained is decreased with increase of milling time. The duration of mechanochemical activation affects the physical properties of nanocomposites studied. Addition of a small amount of nanotubes into Fe-Cu charge results in a significant increase of strength of the Fe-Cu (4:1) + CNT nanocomposite materials (NCMs) obtained.

The aim of this research is to study the influence of the multi-walled carbon nanotubes (MWCNTs) on the thermomechanical and structural properties of high-density polyethylene. Several, complementary experimental techniques were used, namely, dilatometry, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Raman spectroscopy, and infrared (IR) spectroscopy. Dilatometry data showed that nanocomposites exhibit anisotropic behavior, and intensity of the anisotropy depends on the MWCNT concentration. The shapes of the dilatometric curves of the nanocomposites under study differ significantly for the radial and longitudinal directions of the samples. DSC results show that MWCNTs weekly influence calorimetry data, while Raman spectra show that the I D/I G ratio decreases when MWCNT concentration increases. The IR spectra demonstrate improvement of the crystallinity of the samples as the content in MWCNTs rises.

The objective of this work is a dilatometric study of Al + 0.1% of multiwall carbon nanotubes nanocomposite material (NCM) in three directions: X - parallel to the rolling direction; Y - perpendicular to the rolling direction and (Z) perpendicular to the ribbon plane. NCM specimens were made in the form of a 0.1-mm-thick ribbon. The temperature range used for measurements was 20°C to 600°C. The obtained results show that presence of nanotubes affects the thermal expansion coefficient (TEC) measured in different directions. αx(T) and αy(T) - TEC plots as a function of temperature along X and Y directions, respectively - have substantially the same shape and overlap in the area of 400°C. The expansion along X-axis becomes greater than along Y-axis below this temperature value. It is clear that the coefficient αz(T) is lower than αx(T) and αy(T) over the entire temperature range. The expansion along Z-axis is smaller compared to that along X- and Y-axes. This behaviour suggests that there is a strong interatomic interaction along this direction (Z). αz(T) becomes monotonous and constant and is equal to 8 × 10(-6)°C(-1) at temperatures above 300°C. Such order of magnitude had not been obtained in earlier studies of aluminium alloys. The obtained TEC shows high anisotropy, which grows with the increase of temperature. The heat flow (differential scanning calorimetry, (DSC)) of Al + 0.1% carbon nanotubes (CNT) NCM is more intense compared to that of pure aluminium produced in similar conditions. The two representative curves have similar shape and are almost entirely overlapped. The thermogravimetry results confirm those of DSC. The Raman spectrum of this nanomaterial shows that intensity of G and D bonds is significantly increased compared to that of the pure material. The infrared diagram also confirms that in this case the mentioned bonds are more intensive NCM. The tensile strength measurements (σB) of the studied NCM also demonstrate that its value increases from 140 ± 10 MPa for Al without nanotubes to 200 ± 10 MPa for NCM.

The authors describe results of application of Ho laser "Medilas H" (Dornier) in patients with uroliths located in different parts of upper urinary tracts. The results of new approaches to uroliths fragmentation in different parts of the ureter are outlined.