Properties of tantalum oxide thin films grown by atomic layer deposition

Thin tantalum oxide films were deposited using atomic layer deposition from TaCl₅ and H₂O at temperatures in the range 80–500 °C. The films deposited at temperatures below 300 °C were predominantly amorphous, whereas those grown at higher temperatures were polycrystalline containing the phases TaO₂ and Ta₂O₅. The oxygen to tantalum mass concentration ratio corresponded to that of TaO₂ at all growth temperatures. The optical band gap was close to 4.2 eV for amorphous films and ranged from 3.9 to 4.5 eV for polycrystalline films. The refractive index measured at λ = 550 nm increased from 1.97 to 2.20 with an increase in growth temperature from 80 to 300 °C. The films deposited at 80 °C showed low absorption with absorption coefficients of less than 100 cm⁻¹ in the visible region.     

One-pot synthesis of mesoporous SBA-15 containing protonated 3-aminopropyl groups

A new technique of synthesis of mesoporous silica with protonated amino groups avoiding microwave treatment of mesophase was developed using a template method. The block-copolymer P123 was used as a template and sodium meta-silicate with 3-aminopropyltriethoxysilane as precursors. After the removal of template from mesophase with boiling ethanol, the obtained sample displayed highly ordered hexagonal structure with attractive textural parameters: S_BET = 460 m² g^?1, V_total = 0.79 cm³g^?1 and d = 7.1 nm. FTIR and ¹³C CP/MAS NMR spectroscopy revealed the presence of alkyl ammonium groups (0.7 mmol g^?1) that were able to attach anions of molybdophosphoric acid to the surface of the synthesized mesoporous material. The resulting anion-ion exchange phase can find applications in many areas (adsorption, catalysis, etc.).     

Gold nanoparticles into Ti1−xZnxO2 films: Synthesis,structure and application

The gold particles of certain size were incorporated into Ti_1−xZn_xO₂ films by sol–gel method. The synthesis conditions predetermine the size and shape of gold nanoparticles, which were monitored by the absorption spectra and SEM images. The results of Raman spectra measurements indicate that Au nanoparticles inhibit the grain growth of anatase within the film. The photocatalytic activity of Au/Ti_1−xZn_xO₂ films in the degradation of tetracycline hydrochloride depends on the sizes of Au particles.     

Large-scale synthesis of organophilic zirconia nanoparticles and their application in organic-inorganic nanocomposites for efficient volume holography

We present a multigram scale, one-step nonaqueous synthesis route to monodisperse, highly crystalline ZrO(2) nanoparticles. The nanoparticles can be stabilized in nonpolar solvents via a simple functionalization procedure using only minute amounts of organic stabilizers. Their great potential in materials applications is demonstrated by the fabrication of organic-inorganic nanocomposites that can be selectively photopolymerized to inscribe extremely effective and volume holographic gratings with the highest refractive index contrast (n(1) of up to 0.024) achieved so far.     

Deformation Characteristics of Leather for Shoe Upper,Filled with Natural Minerals

A promising direction in the tanning industry is the use of natural minerals as environmentally friendly technologically efficient materials that are able to adjust and regulate the efficiency of formation of the dermis structure and the properties of finished leather. The use of finely-dispersed minerals promotes alignment of topographic areas in thickness, increases the yield of leather on the area by avoiding bonding structural elements of the dermis. Changes in the microstructure of the dermis, as a result of mineral filling, contribute to improvement of performance and hygienic properties of finished leather. And the study of the properties of the specified skins should be consistent with the features of operations on their cutting, shoe molding and shoe upper fixing preparations. The most important properties of leather materials, which largely determine the quality of basic technological operations of shoe manufacturing are the deformation properties. Lack of information about relaxation and deformation properties of the leather produced by the new technologies do not allow to predict their ability to form shapes and save it--indicates the relevance of this study. This paper analyzes relaxation and deformation characteristics of natural leather for shoe uppers, filled with natural minerals montmorillonite and zeolite, and the ability to predict their formation and preservation of shape in service. Features of deformation of the skin with mineral content were assessed by determining single-cycle characteristics when attaching to a complete test cycle ＂loading-unloading-rest＂ sample. Correlations of elastic and plastic （permanent） deformation have been established, kinetics of changes in linear characteristics of the samples after removal of the load has been investigated. Introduction of dispersions of mineral to the structure of the dermis contributes to the strength of semi-finished leather, increase of the uniformity of mechanical properties in the longitudinal and transverse directions and rise of shape stability index. It is shown that the direction of this study allows us to offer new competitive ecologically friendly materials to produce shoes.     

Cryostructured and Crosslinked Viable Cells Forming Monoliths Suitable for Bioreactor Applications

Applications of immobilized biocatalysts in both research and industry require highly active catalysts, preferably at a low cost. In this study, cryogels with high catalyst density were produced through cryostructuration of whole Escherichia coli (E.coli) cells. Prepared cryogels are macroporous materials composed of metabolically active cells crosslinked to each other via polymeric structures. Different macromolecular reagents: oxidized dextran (OxDex), polyvinyl alcohol (PVA) and polyethyleneimine (PEI), the two latter activated with glutaraldehyde (GTA) have been synthesized. Prepared polymers were tested as effective and mild crosslinkers for cells during the cryostructuration procedure. Combination of the two synthetic polymers: PEI+GTA and PVA+GTA was found most suitable for formation of macroporous and stable structures from cells without any toxic effect on them. About 90 % of β-glucosidase activity in cells was retained after crosslinking with a combination of synthetic polymers, whereas E. coli crosslinked using GTA showed complete loss of activity. Preserved viability of cells in cryogel offers possibility to induce protein expression in cells after crosslinking. For β-glucosidase induction post immobilization yielded 50 % activity of that from cells induced in free form before cryo-structurization. The results of the post immobilization studies indicate an interesting potential for handling very sensitive enzymes.     

Acousto-optic interaction in alpha-BaB(2)O(4)and Li(2)B(4)O(7) crystals

Experimental studies and analysis of acousto-optic diffraction in alpha-BaB(2)O(4) and Li(2)B(4)O(7) crystals are given. Ultrasonic wave velocity, elastic compliance and stiffness coefficients, and piezo-optic and photoelastic coefficients of alpha-BaB(2)O(4) and Li(2)B(4)O(7) crystals are determined. The acousto-optic figure of merit has been estimated for different possible geometries of acousto-optic interaction. It is shown that the acousto-optic figures of merit for alpha-BaB(2)O(4) crystals reach the value M(2)=(270 +/- 70) x 10(-15) s(3)/kg for the case of interaction with the slowest ultrasonic wave. The directions of propagation and polarization of those acoustic waves are obtained on the basis of construction of acoustic slowness surfaces. The acousto-optic diffraction is experimentally studied for alpha-BaB(2)O(4) and Li(2)B(4)O(7) crystals.     

Therapeutic Effects of Hypoxic and Pro-Inflammatory Priming of Mesenchymal Stem Cell-Derived Extracellular Vesicles in Inflammatory Arthritis

Mesenchymal stem cells (MSCs) immunomodulate inflammatory responses through paracrine signalling, including via secretion of extracellular vesicles (EVs) in the cell secretome. We evaluated the therapeutic potential of MSCs-derived small EVs in an antigen-induced model of arthritis (AIA). EVs isolated from MSCs cultured normoxically (21% O₂, 5% CO₂), hypoxically (2% O₂, 5% CO₂) or with a pro-inflammatory cytokine cocktail were applied into the AIA model. Disease pathology was assessed post-arthritis induction through swelling and histopathological analysis of synovial joint structure. Activated CD4+ T cells from healthy mice were cultured with EVs or MSCs to assess deactivation capabilities prior to application of standard EVs in vivo to assess T cell polarisation within the immune response to AIA. All EVs treatments reduced knee-joint swelling whilst only normoxic and pro-inflammatory primed EVs improved histopathological outcomes. In vitro culture with EVs did not achieve T cell deactivation. Polarisation towards CD4+ helper cells expressing IL17a (Th17) was reduced when normoxic and hypoxic EV treatments were applied in vitro. Normoxic EVs applied into the AIA model reduced Th17 polarisation and improved Regulatory T cell (Treg):Th17 homeostatic balance. Normoxic EVs present the optimal strategy for broad therapeutic benefit. EVs present an effective novel technology with the potential for cell-free therapeutic translation.     

Fibrosis Protein-Protein Interactions from Google Matrix Analysis of MetaCore Network

Protein–protein interactions is a longstanding challenge in cardiac remodeling processes and heart failure. Here, we use the MetaCore network and the Google matrix algorithms for prediction of protein–protein interactions dictating cardiac fibrosis, a primary cause of end-stage heart failure. The developed algorithms allow identification of interactions between key proteins and predict new actors orchestrating fibroblast activation linked to fibrosis in mouse and human tissues. These data hold great promise for uncovering new therapeutic targets to limit myocardial fibrosis.     

Trabecular Bone Parameters,TIMP-2, MMP-8, MMP-13, VEGF Expression and Immunolocalization in Bone and Cartilage in Newborn Offspring Prenatally Exposed to Fumonisins

Fumonisins are protein serine/threonine phosphatase inhibitors and potent inhibitors of sphingosine N-acyltransferase (ceramide synthase) disrupting de novo sphingolipid biosynthesis. The experiment was conducted to evaluate the effects of fumonisins (FB) exposure from the 7th day of pregnancy to parturition on offspring bone development. The rats were randomly allocated to either a control group (n = 6), not treated with FBs, or to one of the two groups intoxicated with FBs (either at 60 mg FB/kg b.w. or at 90 mg FB/kg b.w. Numerous negative, offspring sex-dependent effects of maternal FB exposure were observed with regards to the histomorphometry of trabecular bone. These effects were due to FB-inducted alterations in bone metabolism, as indicated by changes in the expression of selected proteins involved in bone development: tissue inhibitor of metalloproteinases 2 (TIMP-2), matrix metalloproteinase 8 (MMP-8), matrix metalloproteinase 13 (MMP-13), and vascular endothelial growth factor (VEGF). The immunolocalization of MMPs and TIMP-2 was performed in trabecular and compact bone, as well as articular and growth plate cartilages. Based on the results, it can be concluded that the exposure of pregnant dams to FB negatively affected the expression of certain proteins responsible for bone matrix degradation in newborns prenatally exposed to FB in a dose- and sex-dependent manner.