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It is established that iron is oxidized by supercritical water (SCW) with the formation of H and nanoparticles of iron oxides (FeO, FeO, and γ-FeO). The kinetics of H production and iron oxidation has been studied by SCW injection at T = 673, 723, 773, 823, and 873 K into a reactor with iron particles. Data of X-ray diffraction and transmission electron microscopy show that the phase composition and morphology of synthesized oxide nanoparticles depend on the SCW temperature. [ABSTRACT FROM AUTHOR]

We have designed a transmission line model of the microwave coupling mechanism for a microwave pumped CO2 laser. The model is a total loss ridge waveguide transmission line having nonuniform impedance. The laser plasma is modeled as a frequency-dependent lossy dielectric and acts as a distributed resistance in the length of the microwave cavity. The coupling structure of the microwaves is designed not to be resonant at the microwave source frequency of 2.45 GHz at 1 kW and propagating the total microwave field energy to be absorbed without internal reflection. An exact solution to this general transmission line propagation constant for a shunt resistance along length of the guide is found. The measurements and predictions of the parameters of the plasma conductivity as a function of the attenuation constant agree closely. [Copyright &y& Elsevier]

The buckling resistance of imperfect circular cylindrical shells of elastic and isotropic material subject to axial compression is studied focusing on initial geometric imperfections. Considering the imperfections as a random field, the suggested probabilistic representation of the buckling resistance parallels the deterministic dependence of buckling loads on the size and shape of imperfections. It derives from the probability density function of an imperfection size measure and the conditional probability density functions of the resistance confined to the realizations of imperfections given their size levels. The separated representation of the buckling resistance allows: (1) supplementary checking the accuracy of the random field representation, (2) classifying measured and simulated imperfections by their size and shape effects on buckling loads, (3) prospective delimiting the range of working imperfections for fabrication tolerance classes, and (4) defining the characteristic imperfection for the semi-probabilistic design. Introductory calculations illustrate the dependence of the normalized buckling loads of a shell on the shape and size of imperfections. • Shells in axial compression considering geometric imperfections as a random field. • A probabilistic representation of the buckling resistance of the imperfect shells. • Separating the size and shape effects of imperfections on the buckling resistance. • Supplementary checking the accuracy of a random field representation. • Defining the characteristic imperfection for the semi-probabilistic design. [ABSTRACT FROM AUTHOR]

We report on a study of laser plasma instabilities with 527 nm laser pulses in an intensity range of 0.5 × 10 13 − 1.1 × 10 15 W cm − 2 and plasma parameters entering a regime that is relevant for direct drive inertial confinement fusion. Using the kilojoule high repetition rate L4n laser at the Extreme Light Infrastructure—Beamlines, more than 1300 shots were collected, and the onset and the growth of stimulated Brioullin scattering (SBS) and stimulated Raman scattering (SRS) were studied with a high confidence level. The measured onset intensities are 0.2 × 10 14 W cm − 2 for SBS and 1.4 × 10 14 W cm − 2 for SRS. At the maximum intensity, the total fraction of backscattered energy reaches 2.5% for SBS and 0.1% for SRS. These results are of high relevance for advanced concepts for inertial fusion energy, which rely on the use of 527 nm laser light to drive the implosion of the fuel target, and in particular, they can be used as a benchmark for advanced simulations. [ABSTRACT FROM AUTHOR]

The calcium-carbonate-induced mineralization of multilayer shells of emulsion capsules, formed using layer-by-layer assembly of polyelectrolytes, has been investigated. Optimal conditions for forming microcapsules with a core from shea butter and an organic–inorganic shell from synthetic polyelectrolytes and calcium carbonate are found. The shell morphology and stability of capsules in an aqueous suspension upon heating are investigated, and their cytotoxicity for human fibroblast cells is estimated. It is shown that mineralization of emulsion polyelectrolyte capsules by calcium carbonate in the form of vaterite strengthens the capsule walls and increases their biocompatibility. [ABSTRACT FROM AUTHOR]

Previous studies have demonstrated the applicability of alpha-fetoprotein or its receptor-binding domain fused to the 6-histidine tag at the C-terminus (rAFP3D-His6) as vectors for targeted delivery of antitumor agents. The His6 tag is undesirable for further preclinical trials. Therefore, we designed a recombinant protein rAFP3D without any affine tags and assessed its functional activity. The protein was produced as inclusion bodies in Escherichia coli BL21 (DE3) cells. Optimal conditions for washing inclusion bodies and refolding the target protein were selected. We used a saturated (NH4)2SO4 solution at the primary purification stage to precipitate the main fraction of nontarget proteins. The second purification step included hydrophobic interaction chromatography using butyl-cellulose. The identity of the protein sequence was confirmed by tandem mass spectrometry. Circular dichroism demonstrated the authenticity of the secondary structure of the recombinant protein. MCF-7 tumor cells actively internalized fluorescently labeled rAFP3D. These results indicate that rAFP3D can be used for targeted drug delivery. [ABSTRACT FROM AUTHOR]

Formation of zinc sulfide nanoparticles was detected during interaction of bulk samples with hydrogen sulfide at supercritical parameters. Synthesis proceeds with liberation of H by the reaction nZn + nHS = (ZnS) + nH. It has been found by the X-ray diffraction method, scanning electron microscopy, and mass spectrometry that the addition of water stimulates coupled reactions of nanoparticle synthesis nZn + nHO = (ZnO) + nH and (ZnO) + nHS = (ZnS) + nHO and brings about an increase in the synthesis rate and morphological changes of (ZnS) nanoparticles. [ABSTRACT FROM AUTHOR]

Synthesis of ZrO during oxidation of a zirconium wire by supercritical water at P = 25 MPa and T = 500 or 525°C has been investigated. It is established that an inhomogeneous nanostructured ZrO layer is formed as a result of oxidation. Rate of 〈Zr〉 oxidation, oxide porosity and morphology, and average size and structure of crystallites are determined. The thermal conductivity of the synthesized ZrO layer in supercritical water and in nitrogen is determined by pulsed electric heating of a partially oxidized wire. The low values of thermal conductivity (about 0.2 W/(m K)) correspond to a layered structure of porous material, with layers orientated parallel to the oxidized-metal surface. [ABSTRACT FROM AUTHOR]

• Buckling of axially compressed cylindrical shells with geometric imperfections. • Varying shell dimensions and the energy measure of geometric imperfections. • A strain energy based relationship linking energy measures of individual shells. • The least FEM GNIA buckling loads and the NASA and Eurocode knock-down factors. • Shareable imperfections and probabilistic estimates of the least buckling loads. This article conducts a theoretical study of the experimentally observed dependency of lower normalized buckling loads of axially compressed cylindrical shells on the radius-to-thickness ratio R / t. Medium length shells are studied, of equally elastic and isotropic material and of different dimensions. Given that geometric imperfections are viewed as a main source of imperfection sensitivity, their magnitudes are adjusted for individual shells by a previously introduced energy measure. The measure is defined as the square root of the total strain energy (linear analysis) of the shell deformed in the shape of an imperfection. Within the specified group, a relationship linking different energy measures of individual shells is suggested. The link is defined by the total strain energy per unit volume of a shell, which is a function of the shape and size of an imperfection and of the R / t ratio and the length-to-circumference/radius ratio. By equating a certain level of the function throughout the group of shells, a linked level of the energy measure of imperfections is provided for every single shell using a simple formula. Numerical examples showing the imperfection sensitivity of the shells for three-dimensional configurations are presented. FEM GNIA buckling strength calculations are based on a recently developed approach which employs the so-called influential eigenmode imperfections. The results are then compared to the lower bound knock-down factors recommended by NASA SP-8007 and to the normalized design buckling loads of Eurocode 1993-1-6. Furthermore, the authors propose an application of the linking ratio concerning shareable imperfection measurements and preliminary probabilistic estimates of the theoretical lower bound knock-down factors. [ABSTRACT FROM AUTHOR]

Reactive oxygen species are generated by the redox reaction involving metalloporphyrin and ascorbic acid (AA) and lead to oxidative stress followed by cancer cell death. Polymer particles based on the copolymer of lactic and glycolic acid (PLGA) containing FeIIICl-tetraphenylporphyrin (FeClTPP) were prepared and characterized. These particles in combination with AA exhibit cytotoxic activity against the K562 (human chronic myelogenous leukemia) and MCF7 (human breast adenocarcinoma) cell lines. Results in vitro indicated significant antitumor efficiency on mice inoculated with P388 leukemic cells and treated with FeClTPP/AA. The cytotoxic activity of the combined system is achieved due to the formation of reactive oxygen species. The application of this system to the study of anticancer efficiency in vivo on the model of mice that were hypodermically inoculated with P388 lymphocytic leukemia revealed a significant inhibition of tumor growth. The use of FeClTPP in combination with AA seems to be promising in cancer treatment. [ABSTRACT FROM AUTHOR]

MgAl 2 O 4 is a versatile and stable oxide that is useful in various applications. However, the presence of impurities originating as a part of the powder synthesis process can potentially impair desired properties. In this work, we performed acidic treatments with mixtures of HNO 3 and H 2 SO 4 on commercial MgAl 2 O 4 nanopowders. The treated powder structure and morphology was found to be largely retained, while changes in specific surface area, adsorbed CO 2 , and sulfur content were detected. Two sulfur species populations were identified (i.e., S2+ and S6+) and their concentration throughout the surface and bulk of the particles was analyzed. Notably, S2+ was beforehand unknown as a contaminant in MgAl 2 O 4. The S2+ concentration could be diminished below detection limit of XPS by increasing the percentage of H 2 SO 4. The insights gained on sulfur impurities present in commercial nanopowders and their removal possibilities or limitations can help utilize such oxides in applications sensitive to chemical purity. [Display omitted] • Commercial MgAl 2 O 4 nanopowders were acid treated for removal of sulfur impurities. • Sulfur content was analyzed by X-ray photoelectron spectroscopy depth profiling. • Two distinct types of sulfur species (S2+ and S6+) have been identified. • The S2+ species has been documented in MgAl 2 O 4 for the first time. [ABSTRACT FROM AUTHOR]

Silybin (Slb) and ursodeoxycholic acid (UDCA) are hepatoprotectors used in the pathogenetic therapy of liver and biliary tract. However, low bioavailability of these drugs restricts their application. In order to solve this problem, Slb and UDCA were incorporated into polymer carriers based on polylactic acid and poly(lactic-co-glycolic acid) by nanoprecipitation. The polymeric forms obtained according to the developed and optimized method are nanoparticles with a size from 100 to 200 μm. In vitro experiments showed a 1.5-2-fold higher hepatoprotective activity of Slb- and UDCA-containing polymeric nanoparticles compared to free substances. [ABSTRACT FROM AUTHOR]

Polymer particles containing carboplatin (CPt) were developed by the inclusion of this antitumor agent in a copolymer of lactic and glycolic acids (PLGA-COOH 50/50). The polymer particles were found to have a spherical form with an average diameter not exceeding 200 nm, the ζ-potential is equal to-32.2±1 mV. The CPt-loaded polymer particles possess a cytotoxic activity against human small cell and non-small cell lung carcinoma (lines H69 and A549), as well as against mouse mammary adenocarcinoma (line Ca755). The results of the in vivo studies carried out on female mice of line CBl/6 with inoculated mouse melanoma of line B16 showed increasing of lifespan of the animals and inhibition of tumor growth for groups treated with the polymer particles, as compared to the animals treated with the drug substance CPt. [ABSTRACT FROM AUTHOR]

Temozolomide (TMZ) is a cytostatic drug used in treatment of patients with malignant gliomas and melanomas. The development of innovative formulations for delivery of TMZ into target cells in order to reduce its systemic toxicity and gain prolonged effect is a topical problem of modern biotechnology and pharmacology. The article presents experimental data on development of the TMZ polymer-based formulation. The TMZ formulation presents nanoparticles with average size of 300 nm exhibiting high in vitro cytotoxic activity against melanoma and glioma cells (cell lines C6, U377MG, B16, and Mel-10). Melanoma (B16 cell line) bearing mice (C57Bl/61) treated by TMZ polymer nanoparticles revealed inhibition of tumor growth and increase of the animal lifespan. Also, loading of TMZ into the polymer particles was shown to decrease acute toxicity of the drug compared to the intact drug. [ABSTRACT FROM AUTHOR]

The autothermal regime of partial oxidation of carbonized coal residue in a stream of water-oxygen fluid at 923 K and 30 MPa is implemented for the first time. It is revealed that the oxidation of coal residue and the formation of combustible gases (hydrogen content in the products is increased by 26% with respect to its amount in the original sample) occur simultaneously and are caused by the participation of the HO molecules in the redox reactions. [ABSTRACT FROM AUTHOR]

The present study focused on the fabrication of bulk materials from Ti 1− x Al x N nano-powders using a spark plasma sintering (SPS) apparatus. Super-saturated Ti 1− x Al x N solid solutions containing differing fractions of AlN (10, 20, 30 and 50 mol%) were synthesized by high-energy ball milling (HEBM) of pure nitrides. The complete dissolution of AlN in TiN was achieved after 100 h of milling. The milled powders were characterized by X-ray diffraction, scanning electron microscopy, energy-filtered transmission electron microscopy spectra imaging and energy dispersive X-ray spectroscopy. The crystalline size of the mechanically alloyed powders after 100 h of milling was about 12–14 nm. Ti 1− x Al x N powders of various compositions were sintered by SPS under pressure of 63 MPa at 1673 K. Maximal hardness and bending strength values (610 MPa and 18.6 GPa, respectively) were obtained for composites containing 20 mol%AlN. Powder with 20% mole%AlN was consolidated under pressure of 500 MPa in the 1273–1423K temperature range by high pressure SPS (HPSPS). A fully dense nano-structured specimen, processed at 1423 K, displayed a Young modulus of 420 GPa, hardness of 20.5 GPa, bending strength of 670 MPa and fracture toughness of 7.1 MPa m 0.5 . [ABSTRACT FROM AUTHOR]