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The study aimed at evaluation of the rheological properties of aqueous suspensions of SiC stabilized with either TMAH (tetramethyloammonium hydroxide) or NaOH in the amount of a given dispersant in the range of 0–1.0 wt% as calculated on the dry mass of SiC powder. The optimal amount of the dispersants was finally evaluated at 0.4–0.6 wt %, based on the results of rheological studies (flow curves and viscosity curves) and the sedimentation rate, which corresponded to the pH of the suspension within the range of 9.5–10.5. The amount of the dispersant here did not depend on the solid volume fraction in the suspension, but rather, according to the zeta potential measurement results, the pH range guaranteed the formation of a stable suspension. This effect allowed to propose a dispersant mechanism for stabilizing the suspension. The maximum amount of silicate anions formed, accordingly, in the pH range of 9.5–10.5 on the surface of SiC particles, which in turn could be able to adsorb Na+ or TMA+ cations and thus increase the thickness of the Stern layer, increasing electrostatic repulsion between the SiC particles and improving the stabilization of suspensions and their rheological properties. However, the increase in suspension pH deteriorated their stabilization – most likely due to the occurrence of polymerization of amorphous silica and the presence of additional cations in water increasing its ionic strength. These suggestions were confirmed by the results of XPS analysis of the chemical state of SiC particle surfaces.

International audience; The catalytic decomposition of N2O was studied over a series of calcined Mn(Fe)CoAl hydrotalcite-like compounds. The precursors were prepared by coprecipitation and characterized by XRD and TGA. The mixed metal oxides derived after calcination at 600 °C were characterized by XRD, N2 adsorption, H2-TPR and XPS. Moreover, in situ XAFS measurements over selected mixed metal oxides were performed. Such investigations under relevant reaction conditions are rare, while a comprehensive understanding of the involved active species may facilitate a knowledge-based catalyst optimization. The activity of the CoAlOx (Co/Al = 3/1, mol.%) catalyst varied depending on the loading of Mn or Fe (0.0575, 0.0821, 0.1150, 0.1725, 0.2300, mol.%). In the investigated series, Mn0.1725Co3AlOx reached the highest activity with T50 of about 305 and 376 °C under N2O/N2 and N2O,NO,O2/N2 feed, respectively. In situ X-ray absorption experiments over Mn0.1725Co3AlOx suggested that MnxCoyO4 spinels undergo reduction to CoO and MnO upon heating up to 600 °C in He. Under N2O/He conditions, initial reoxidation of cobalt species began at 350 °C. The lower activity obtained for Fe0.1725Co3AlOx is explained by the fact that the majority of Fe was not incorporated into the Co3O4 structure but instead formed less reactive iron oxide clusters.

Usage of CNTs as matrix modifiers during fabrication of CNFs from the electrospun polymer precursor is an interesting approach to obtain composite materials with a new set of properties. However, the progress in this field is hindered by the lack of consistency of the CNTs used in the studies and sometimes insufficient materials characterization. In this study, two types of CNTs were at first characterized to reveal their chemical composition and morphology (by TEM and XPS) and then used as matrix additives in the process of electrospinning. The outcome product was evaluated for morphology (SEM), chemical composition (XPS, FTIR), course of thermal transition (STA-FTIR) and level of structural arrangement (TEM combined with SAED) to answer the question how do CNTs interact with polymer matrix and how it impacts the process of thermal transition and properties of the as-received carbon nanofibers. Highly oxidized and short CNTs were found to increase the structural arrangement, catalyzing the thermal transition, while thin and long CNTs, with low amount of oxygen, entrap the nitrogen atoms, yielding nitrogen-doped CNFs that might be suggested as high-performance oxygen reduction reaction catalysts.

The aim of this work was to investigate how chemical functionalization affects the electronic properties of multi-walled carbon nanotubes, altering the electrophoretic deposition process: a method of choice for the fabrication of high quality, all-carbon nanotube (CNT) layers. Wet chemistry methods were applied to modify the surfaces of CNTs by insertion of various oxygen- and nitrogen-containing groups. Transmission electron microscopy revealed no significant changes in the material morphology, while X-ray photoelectron spectroscopy and Raman spectroscopy showed that changes in the chemical composition did not translate to the changes in the structure. Molecularly modelled optimized surface functional group geometries and electron density distributions allowed the calculation of the dipole moments (–COOH = 0.77; –OH = 1.65; –CON(CH3CH2)2 = 3.33; –CONH2 = 2.00; –NH2 = 0.78). Due to their polarity, the introduction of surface functional groups resulted in significant modifications of the electronic properties of CNTs, as elucidated by work function measurements via the Kelvin method and ultraviolet photoelectron spectroscopy. The work function changed from 4.6 eV (raw CNTs) to 4.94 eV for the –OH functionalized CNTs and 4.3 eV for the CNTs functionalized with –CON(CH3CH2), and was inversely proportional to the dipole moment values. Finally, using CNT dispersions, electrophoretic deposition was conducted, allowing the correlation of the work function of CNTs and the measured electrophoretic current with the impact on the deposits' qualities. Thus, a rational background for the development of carbon-based biomaterials was provided.

Amorphous silicon oxycarbide (SiOC) based materials are customarily called black glasses. In this work, hermetic layers on the steel substrate based on amorphous SiOC were obtained. The material was modified with cerium ions. Based on the literature, Ce as the modifier is responsible for i.e. enhancement of the corrosion resistance of materials and their antibacterial properties. SiCeOC coatings were produced via ceramization of the polymeric precursors synthesized by the sol-gel method and deposited on the metallic substrates with the use of the dip-coating technique. Numerous structural and microstructural studies were applied for the examination. It was proven that cerium is present in the material in the form of the inclusions and the material might be described as the SiOC/CeO2 composite. The surface properties such as roughness, wettability and surface free energy were also analyzed. Corrosion resistance tests were also conducted to establish the influence of the modification with cerium ions on the characteristics of the basal material. The results illustrated that a limited amount of the modifier enhanced corrosion resistance of black glasses without changes in their structure. However, the modification does not promote Ce ion release and the antibacterial tests showed the materials do not possess antibacterial properties.

Physicochemical, electrochemical and biological performance of 4 types of all-carbon nanotube layers was studied. Higher oxidation state of carbon was responsible for micro-scaled uniformity of the layers and excellent electrical conductivity, while nitrogen containing functional groups yielded materials with anisotropy similar to natural tissues and reduced work function. All materials were cytocompatible with mammalian fibroblasts (viability80%, cytotoxicity3% at day 7) and human dermal fibroblast (viability of cells70% at day 1), while reducing bacterial and cancer cells proliferation without adding any drug. After 8 h culture, a ~50% depletion in the number of Gram-positive bacteria was observed on materials with lower work function, while Gram-negative bacteria were more sensitive towards carbon coordination number and presence of nitrogen atoms (cell depletion of up to 48% on amidized carbon nanotubes). After 1-day culture,80% reduction in the melanoma cells number, connected with enhanced production of reactive oxygen species (ROS) was observed. All-carbon nanotube layers decreased bacteria and cancer cell functions without negatively influencing mammalian cells nor using drugs and we believe that this can be explained by various sensitivity of the tested cells towards exogenous ROS overproduction. As the concerns over implant-related infections as well as rates of antibiotic-resistant bacteria and chemotherapeutic-resistant cancer cells are growing, such materials should pave the way for a wide range of biomedical applications.

The quality and relevance of nanosafety studies constitute major challenges to ensure their key role as a supporting tool in sustainable innovation, and subsequent competitive economic advantage. However, the number of apparently contradictory and inconclusive research results has increased in the past few years, indicating the need to introduce harmonized protocols and good practices in the nanosafety research community. Therefore, we aimed to evaluate if best-practice training and inter-laboratory comparison (ILC) of performance of the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay for the cytotoxicity assessment of nanomaterials among 15 European laboratories can improve quality in nanosafety testing. We used two well-described model nanoparticles, 40-nm carboxylated polystyrene (PS-COOH) and 50-nm amino-modified polystyrene (PS-NH2). We followed a tiered approach using well-developed standard operating procedures (SOPs) and sharing the same cells, serum and nanoparticles. We started with determination of the cell growth rate (tier 1), followed by a method transfer phase, in which all laboratories performed the first ILC on the MTS assay (tier 2). Based on the outcome of tier 2 and a survey of laboratory practices, specific training was organized, and the MTS assay SOP was refined. This led to largely improved intra- and inter-laboratory reproducibility in tier 3. In addition, we confirmed that PS-COOH and PS-NH2 are suitable negative and positive control nanoparticles, respectively, to evaluate impact of nanomaterials on cell viability using the MTS assay. Overall, we have demonstrated that the tiered process followed here, with the use of SOPs and representative control nanomaterials, is necessary and makes it possible to achieve good inter-laboratory reproducibility, and therefore high-quality nanotoxicological data. European Commission | Ref. EC FP7 QualityNano (INFRA-2010-1.1.31- 262163) Fonds National de la Recherche of Luxembourg | Ref. NANION (FNR / 12 / SR / 4009651) Direction générale opérationnelle de l’Economie, de l’Emploi et de la Recherche (Walloon, Belgium) | Ref. ‘QNano’ (2011-14) n. 1117448 Norwegian Research Council | Ref. NorNANoREG 239199/070

The researches presented in this work were devoted to electrochemico-chemical regeneration of exhausted electrode made of expanded graphite (EG). The aimed process was conducted by electrochemical treatment and ozone flow performed together in wet environment. EG was covered with insoluble products of incomplete oxidation of phenol formed during cyclic voltammetry measurement. The same electrochemical technique was applied for evaluation of regeneration efficiency. To understand the process of EG regeneration, the electrode was characterized by calculating of BET surface, FTIR and XPS analysis. Moreover, SEM images of the investigated samples were also done. Obtained results have showed the success of regeneration treatment, which led to significant enhancement of electrode activity compared to original EG. The present work also revealed that the mechanism of phenol electrooxidation is changed after the regeneration treatment of electrode material. This effect is probably caused by the modification of chemical composition of EG surface due to its interactions with OH radicals intensively generated during the process of regeneration.

Titanium dioxide in the form of anatase is known to be a good photocatalyser but catalytic properties strongly depend on TiO2 grain size, morphology and surface area of thin film. The aim of this study was to evaluate influence of carbon nanotube additive on photocatalitic properties of TiO2.Titanium dioxide/multiwalled carbon nanotubes (MWCNT) nanocomposites were prepared by sol-gel method in the form of a thin layer on glass substrates. Samples were characterized by X-ray diffraction (XRD) and Grazing Incidence Diffraction (GID), Raman, FTIR and UV-VIS spectroscopy, as well as scanning electron microscopy (SEM). The photocatalytic activity of prepared films was evaluated by the detection of changes in the UV-VIS spectra after the discoloration of Reactive Black V pigment - water solution. It was found that the crystalline TiO2 is composed of anatase phase only. Presence of MWCNTs in the composite increases the size of TiO2 particles. Additive of nanotubes into the TiO2 resulted in an increase in photocatalytic activity in both the UV and visible range by 10 and 50% respectively compare to undoped TiO2. Furthermore, carbon nanotubes lead to better dye adsorption on the surface. Additionally significant reduction in the contact angle, approximately 50% (compare to pure TiO2) was also observed. The obtained results suggest that the TiO2/carbon nanotubes composite material can be activated by light from visible range.

XRD, BET, H2-TPR, UV–vis-DRS, XPS and XAFS were used to characterize a series of Ag and/or Cu – Ag (1–5%), Cu (10–15%) or Ag-Cu (1–1, 1–10, 1.5–10, 5–5% of metal) – supported on γ-Al2O3. Correlation between physicochemical properties, catalytic activity and selectivity in NH3-SCO were thoroughly investigated. Silver species mainly in the form of Ag2O on the Ag/Al2O3 catalysts led to enhanced activity together with drop in N2 selectivity with increasing silver loading up to 5%. A mixture of CuO and CuAl2O4 formed on the Cu/Al2O3 catalysts. Easily reducible highly dispersed CuOx promoted the activity of the catalysts, while bulk CuOx and CuAl2O4 decreased N2 selectivity up to 500 °C. The activity of all Cu-containing materials was inferior to Ag-containing ones. Thus, the gap between the high conversion temperature over Cu/Al2O3 and low N2 selectivity over Ag/Al2O3 was bridged by applying the Ag-Cu/Al2O3 catalysts, with the optimum loading of 1.5 and 10 wt.% for silver and copper, respectively. NH3-TPD, NH3-TPSR and in situ FTIR were used to determine the in situ selective catalytic reduction (i-SCR) mechanism over 1.5% Ag/Al2O3, 10% Cu/Al2O3 and 1.5% Ag-10% Cu/Al2O3 respectively. The i-SCR mechanism involved the partial oxidation of NH3 into NOx species, along with adsorbed NOx species interacting with adsorbed ammonia (NHx species) and being reduced to reaction products.

The work was focused on the spectroscopic examination of zirconia-based layers deposited on metallic substrates. Metallic biomaterials belong to the group of well-known and most widely applied materials in medicine. They might be characterized by the easiness of formation and good mechanical properties. However, the surface properties of the material need to be strictly controlled to prevent corrosion processes and ensure biocompatibility. One of the modifications leading to improvement of the properties important in terms of considering the material for biomedical applications was the fabrication of ceramic layers on the surface. Presented zirconia-based layers doped with calcium and hydroxyapatite were obtained using the sol-gel method and deposited on the metallic (titanium and steel) surface with the use of dip-coating technique and electrophoretic deposition (EPD) method. Obtained layers were examined with multiple spectroscopic and microscopic methods such as Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM) and atomic force microscopy (AFM). Also the surface properties – wettability and surface free energy (SFE) – were measured. Bioactivity of the obtained layers was evaluated by the in vitro test in simulated body fluid (SBF) - the so-called Kokubo test.

N2O is a potent greenhouse gas released among others in nitric and adipic acid production as well as from stationary and mobile combustion sources. A catalytic decomposition is highly attractive but requires catalysts active over a broad temperature range and in the presence of inhibiting compounds such as NO and O2. Ag-doped Co-(Mg)-Al-Ox mixed metal oxides obtained by the coprecipitation of metal nitrate precursors followed by calcination were evaluated as potential catalysts for N2O decomposition (deN2O) also in the presence of NO and/or O2. Ag integration during synthesis proved to be essential for superior catalytic activity. The catalyst with the optimum composition, AgCo3Al-Ox (Co/Al=3:1 mol %, 1.0 wt % Ag), achieved full N2O conversion at 350 and 450 °C under N2O/N2 and N2O/NO/O2/N2 conditions, respectively. Catalyst characterization, with a focus on H2 temperature-programmed reduction and X-ray photoelectron spectroscopy, evidenced that abundant Ag0 on the surface of (1.0–2.8 wt %)AgCo3Al-Ox enhanced the reduction of cobalt spinels to enable the superior catalytic performance.

Ag-, Ce- and Ga-promoted Cu–Mg–Al hydrotalcite derived mixed metal oxides were obtained by standard coprecipitation, followed by calcination. The obtained Ag(Ce, Ga)–Cu–Mg–Al–O x mixed metal oxides were characterized with respect to their crystalline structure (XRD, TEM), texture (BET), surface acidity (NH 3 -TPD), redox properties (H 2 -TPR), chemical surface composition (XPS), and tested in the selective catalytic oxidation of ammonia into nitrogen and water vapour (NH 3 -SCO). The loading of Ag y -, Ce y -, or Ga y –Cu 5 –Mg 66− y –Al 29 ( y = 0–1) had a clear effect on the catalytic performances. For materials with low metal loadings ( y ≤ 0.25), the redox properties determined the catalytic performances in NH 3 -SCO. The formation of easily reducible CuO x played a crucial role for enhanced catalytic activity at lower temperatures, with a drop in the selectivity to N 2 at higher temperatures. Higher metal loading ( y ≥ 0.5) led to the formation of surface and bulk copper oxide species, and other aggregated metal oxide phases, which enhanced the catalytic activity for Ag–Cu–Mg–Al–O x , and diminished activity for Ce(Ga)–Cu–Mg–Al–O x .

The paper studies an influence of Ga2O3, PbO and BaF2 on the thermal stability of tellurite glass and their properties: thermal expansion coefficient, transmittance and refractive index. Three series of gallium-tellurite glass were prepared: I – (100 − x)TeO2·xGa2O3 where x = 5, 10, 15 and 25 mol%, II – (85 − x)TeO2·15Ga2O3·xBaF2 where x = 1, 3, 6, 11 mol%, III – (90 − x)TeO2·10Ga2O3·xPbO where x = 0, 5, 10 mol%. It was confirmed that stable gallium-tellurite glass can be produced without applying super-cooling methods in the range 5–15 mol% Ga2O3. Ga2O3 acts only as a stabilizer of the TeO2 glassy network when its content not exceed 15 mol%. As shown this effect is connected with the change in crystallization ability of orthorhombic and tetragonal forms of TeO2. It was found that the latter is preferable when Ga2O3 content increases. The increase of the Ga2O3 content over 20 mol% induces its spontaneous crystallization. Admixture of BaF2 and PbO to the Te2O-Ga2O3 glass diminishes a tendency to the glass crystallization. Tellurite glasses with Ga2O3, PbO and BaF2 show good transmittance in the VIS, NIR and MIR up to 5.5 μm. BaF2 and PbO, unlike Ga2O3, decrease the thermal expansion coefficient of tellurite glass. The change in the refractive index due to the admixtures was presented.

Coating the material of choice with a layer of well-adhered carbon nanotubes is a subject of interest in many fields of materials science and industry. Electrophoretic deposition is one of the methods to handle this challenging task. In this process, careful designing of the deposition parameters is crucial in obtaining the product of strictly desired properties. This study was aimed to identify the influence of the diluent on the physicochemical ad electrochemical qualities of the final product. By analyzing the properties of the suspensions being used, we were able to hypothesize on the mechanisms of carbon nanotubes—liquid interactions and their outcome on the thickness, homogeneity, chemical and structural composition and electrical conductivity of the metal substrate covered with a layer of carbon nanotubes. We obtained a materials, composed of metal and a layer of CNTs, with conductivity that is superior to an unmodified metal. This types of materials may find numerous applications in fabrication of novel electronic devices, including the implantable electrodes for biomedicine—as reported in our previous studies, these types of coating are biocompatible.

Materials based on CoSb3 are ranked among thermoelectrics with the highest conversion rate, however in service they tend to rapidly lose the useful properties as a result of oxidation or sublimation. Glass coatings were designed in this work to protect CoSb3 against degradation in air at elevated temperatures. The coatings were based on borosilicate glass with a high content of titania. Their chemical composition was tailored to match the coefficient of thermal expansion (CTE) of the substrate (9.2 · 10−6 K−1) and to secure thermal stability and low softening point of glass. The coatings deposited by a simple dipping technique were fired in the temperature range 700–740 °C. Evaluation of these coatings was based on accelerated oxidation tests at 600 °C for 20 h. The micro- and nanostructure of the CoSb3/glass coating interface were examined by means of advanced electron microscopy. The coating appeared to have good adherence and to effectively protect the thermoelectric substrate against antimony loss and oxidation up to 600 °C. Keywords: Thermoelectrics, CoSb3, Glass coating, Oxidation

The present work demonstrates a simple and low-cost method to produce bulk quantities of graphene material through the thermal treatment of graphite oxide (GO). GO of a high oxidation degree was synthesized by electrochemical overoxidation of natural graphite in 11 M H2SO4 using linear sweep voltammetry (LSV) technique. The thus synthesized GO was thermally exfoliated-reduced at 500 °C in air, giving the final product – thermally reduced graphite oxide (TRGO). It should be emphasized that the process of TRGO formation from electrochemically obtained GO is for the first time described in the present work. Due to shock treatment, the BET specific surface area of TRGO increased from 4 to 455 m2 g−1. Additionally, a decrease in the concentration of oxygen functionalities was also observed. Thermal stability of electrochemically synthesized GO was investigated by thermogravimetric analysis (TGA). In order to characterize the synthesized TRGO, investigations by X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) were performed.

Paulina Kazimierczak,1 Aleksandra Benko,2 Marek Nocun,2 Agata Przekora11Department of Biochemistry and Biotechnology, Medical University of Lublin, Lublin, Poland; 2Faculty of Materials Science and Ceramics, AGH University of Science and Technology, Krakow, PolandCorrespondence: Agata PrzekoraDepartment of Biochemistry and Biotechnology, Medical University of Lublin, Chodzki 1 Street, Lublin 20-093, PolandTel +48 81 448 7026Fax +48 81 448 7020Email agata.przekora@umlub.plBackground: Nanocomposites produced by reinforcement of polysaccharide matrix with nanoparticles are widely used in engineering of biomaterials. However, clinical applications of developed novel biomaterials are often limited due to their poor biocompatibility.Purpose: The aim of this work was to comprehensively assess biocompatibility of highly macroporous chitosan/agarose/nanohydroxyapatite bone scaffolds produced by a novel method combining freeze-drying with a foaming agent. Within these studies, blood plasma protein adsorption, osteoblast (MC3T3-E1 Subclone 4 and hFOB 1.19) adhesion and proliferation, and osteogenic differentiation of mesenchymal stem cells derived from bone marrow and adipose tissue were determined. The obtained results were also correlated with materials’ surface chemistry and wettability to explain the observed protein and cellular response.Results: Obtained results clearly showed that the developed nanocomposite scaffolds were characterized by high biocompatibility and osteoconductivity. Importantly, the scaffolds also revealed osteoinductive properties since they have the ability to induce osteogenic differentiation (Runx2 synthesis) in undifferentiated mesenchymal stem cells. The surface of biomaterials is extremely hydrophilic, prone to protein adsorption with the highest affinity toward fibronectin binding, which allows for good osteoblast adhesion, spreading, and proliferation.Conclusion: Produced by a novel method, macroporous nanocomposite biomaterials have great potential to be used in regenerative medicine for acceleration of the bone healing process.Keywords: XPS, wettability, protein adsorption, osteogenic differentiation, cell proliferation, cryogel

This work demonstrates the adsorption capacity of carbon micro- (CF) and nanofibrous (CNF) adsorbents differing in specific surface area, fiber diameter and open porosity in the removal of NaCl from water. The effect of the adsorption conditions, i.e. contact time, initial salt concentration, and oxidative surface treatment on the adsorption kinetics and equilibrium salt uptake capacity was investigated. Adsorption experiments were carried out by batch-mode experiment at room temperature. The study showed that activated CNF exhibit high adsorption capacity for NaCl, namely 827.5 mgNaCl/gCNF, and this value is over 40 times higher than that of activated carbon and exceeds the values reported for CNT and GO. The adsorption kinetics followed the pseudo-second-order kinetic model and was largely controlled by the intramolecular diffusion rate. The equilibrium data showed a good correlation with the Langmuir and Freundlich isotherms, which supported the complex interaction of salt with the carbon surface. It was shown that salt ions can be attached to the fibrous surface both by ion-exchange mechanisms and electrostatic interactions. The carbon fibrous adsorbents present a new approach to water desalination through the mechanism of adsorption and continuous crystallization, and may be used for the elaboration of new type membranes for water purification and desalination.

The main objective of this paper is to attempt to determine the structure of free carbon phase in SiOC glasses derived from ladder-like silsesquioxane precursors. The samples were fired in argon flowing atmosphere, in a wide temperature range (200–800° C). Conducted XRD, Raman, MIR spectroscopy research allowed to determine the structure of obtained materials. Combined XPS and Raman studies enabled to establishing the point of formation of free carbon in silicon oxycarbide matrix. Two most popular concepts were confronted with Raman and XPS results of free carbon phase in studied materials. This allowed to conclude that for temperatures below 800 °C carbon is present in a form of graphite domains inside glassy matrix.

Structural changes accompanying stabilization and carbonization processes of the two types of polyacrylonitrile (PAN) nanofiber precursors (pure PAN and PAN with carbon nanotubes) were studied using infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The fibrous membranes were preliminary stabilized in air followed by the two-step carbonization process under nitrogen atmosphere. IR absorption spectra showed that the introduction of a small amount of functionalized multiwall carbon nanotubes (MWCNT) into the PAN precursor has a significant impact on its stabilization process. Raman spectroscopy study showed that the structure of carbon nanofibers containing CNT is distinctly more ordered in comparison to pure carbon nanofibers. Based on the XPS analysis the concentration of heteroatoms and the type and amount of functional groups on the surfaces of both types of nanofibers were determined. The results indicate a high potential of functionalized MWCNT as a pyrolysis modifier of polymer precursor leading to the formation of carbon nanofibers with controlled structure and defined chemical state of the surface.

Oxide phases formed at early oxidation stages on unmodified and yttrium-implanted β-NiAl intermetallic compound were studied with the aid of photoluminescence spectroscopy in scales developed at 1473 K for oxidation periods of up to 4 h. Two-stage-oxidation exposures with18O2-tracer were applied. The PLS method was also used to assess the residual stresses in α-Al2O3scale at consecutive stages of its development. It was found that scale formation occurs in a very local way, related to inhomogeneous distribution of Cr in substrate: sometimes distances as short as 10–15 μm were sufficient to observe entirely different phases in the scale. In general, implanted yttrium was found to retard the formation of a stable and protective layer of α-Al2O3. Oxidation for 4 h was necessary for no transient aluminum oxides (mostly θ and/or δ) to be detected, while on non-implanted material they were not found after only 26 min exposure. Only compressive stresses were found in α-alumina scales. They were rather high, reaching even 5 GPa. However, their dependence on the regions in the scale and the scale evolution stage was observed. The results indicate that patches frequently observed in scales on β-NiAl are regions where the phase transformation of transient aluminas to the α phase occurs preferentially. Ridges, which fill the transformation-related cracks, consisted only of α-Al2O3. Combination of these results with those obtained using SIMS distribution analyses of oxygen isotopes as well as with SEM/EDX, enabled very precise conclusions to be inferred concerning the scale growth mechanism. In particular, the local nature of the scale development can be described in more detail. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

The use of methanol as an alternative fuel for gasoline or diesel engines increases the unregulated CH3OH emission. γ-Al2O3 modified with Cu, Mn, Ce, K, Ag, Cu–Mn, Cu–Ce, Cu–Ag or Cu–K (0.5, 1.0, 0.5:0.5, 1.0:1.0 wt% of metal) catalysed the process of methanol incineration. The highest activity reached samples containing 1.0 wt% of silver. Dispersed Ag+ species on Al2O3 served as active species for selective oxidation of CH3OH to CO2 over both Ag/Al2O3 and Cu–Ag/Al2O3. Additionally, the XPS and EPR results revealed the AgO interface between the Ag2O and CuO in the Cu–Ag system.

Lead–gallium glasses, due to the absence of typical glass-forming components, are characterized by an increased tendency to crystallization. Despite this, they are interesting materials due to a shift of IR absorption edge up to 6–7 μm. The paper considers how the SiO2 dopant affects thermal stability and the UV–VIS and IR transmittance of lead-gallium glasses. The base lead-gallium glass (0.75PbO·0.25Ga2O3) was modified by the addition of 5, 10 and 15 mol% SiO2, respectively. DTA/DSC data showed that the glasses are characterized by the multi-stage crystallization, which is changed with the amount of silica doped. The XRD analysis confirmed that: (i) different forms of lead oxide crystallize after heat treatment of the glass, and (ii) the Ga2PbO4 phase is formed at higher temperatures. The silica admixture allowed inserting a few percent of BaF2 into the lead–gallium glass structure. It was found that a transparent glass–ceramic based on the lead-gallium glass with a low phonon barium fluoride phase can be obtained during the thermal treatment. The study of UV–VIS–IR transmittance shows that 10–15 mol% SiO2 in the lead-gallium glasses diminishes the absorption band in the range of 2.6–4 μm due to the presence of hydroxyl groups and simultaneously reduces transmittance in the range of 5–6.5 μm from 10 to 20%. Introduction of SiO2 to the glass results in the increase of transmittance in the shorter wavelength region and the UV-edge shift is observed. It was also confirmed that the BaF2 nanocrystallites exert s no effect on the transmittance of the spectrum analyzed.

Very early stages of development of the oxide scale formed in air at 1150° on unmodified and containing varying amounts of Pt (5, 10 and 15 at.%) β-NiAl intermetallic compound were studied. The scale morphology was observed using scanning electron microscopy, while photoluminescence spectroscopy was applied to determine its phase composition with spatial resolution down to 1 μm. It was found that the scales were non-uniform in terms of their morphology and, to a lesser extent, of their phase composition. Pt additions resulted in earlier development of the α-Al2O3 oxide, which, based also on recently reported literature experimental and modelling results, may be attributed to the increased rate of the scale evolution. The possible direct effect of Pt on the phase transformation of unstable aluminium oxides into α-Al2O3 still needs to be verified as the complementary or alternative explanation. © 2017, Springer Science+Business Media New York.

In this study the role of PI3K/Akt signaling pathway in arsenic trioxide (ATO)-treated parental Jurkat cells and also in derived ATO-resistant clones grown in the presence of given ATO concentration was investigated. ATO-resistant clones (cultured for 8-12weeks in the presence of 1, 2.5 and 5μM ATO) were characterized by high viability in the presence of ATO but slower growth rate compared to the parental cells. Morphological and functional characterization of derived ATO-resistant clones revealed that they did not differ fundamentally from parental Jurkat cells in terms of cell size, level of GSH, the lysosomal fluorescence or CD95/Fas surface antigen expression. However, a slight increase in the mitochondrial potential (JC-1 staining) was detected in the clones compared to parental Jurkat cells. Side population analysis (Vybrant DyeCycle Violet™ staining) in ATO resistant clones did not indicate any enrichment withcancer stem cells. Akt1/2, AktV or wortmannin inhibitors decreased viability of ATO-resistant clones grown in the presence of ATO, with no effect on ATO-treated parental cells. Flow cytometry analysis showed that ATO decreased the level of p-Akt in ATO-treated parental cells, while the resistant clones exhibited higher levels of p-Akt immunostaining than parental Jurkat cells. Expression analysis of 84 genes involved in the PI3K/Akt pathway revealed that this pathway was predominantly active in ATO-resistant clones. c-JUN seems to play a key role in the induction of cell death in ATO-treated parental Jurkat cells, as dose-dependent strong up-regulation of JUN was specific for the ATO-treated parental Jurkat cells. On the other hand, changes in expression of cyclin D1 (CCND1), insulin receptor substrate 1 (IRS1) and protein kinase C isoforms (PRKCZ,PRKCB and PRKCA) may be responsible for the induction of resistance to ATO. The changes in expression of growth factor receptor-bound protein 10 (GRB10) observed in ATO-resistant clones suggest a possibility of induction of different mechanisms in development of resistance to ATO depending on the drug concentration and thus involvement of different signaling mediators.

Titanium dioxide nanomaterials are extensively used in many applications, also for modification of textile materials. Toxicological assessment of such textile materials is currently seldom performed, mainly because of lack of appropriate guidelines. The aim of the study was to assess cytotoxic and genotoxic potential of commercially available TiO2 and TiO2/Ag NMs in pristine form as well as polypropylene fibers modified with the NMs. Both titania NMs showed a cytotoxic effect on BALB/3T3 clone A31 and V79 fibroblasts after 72 - h exposure. Both NMs induced a weak genotoxic effect in comet assay, with TiO2/Ag being more active. In vitro micronucleus test on human lymphocytes revealed a weak mutagenic effect of both materials after 24 h of exposure. In contrast, no significant increase in micronuclei frequency was observed in the in vitro micronucleus test on V79 fibroblasts. The 24-h extracts prepared from polypropylene fibers modified with TiO2/Ag induced a cytotoxic effect on BALB/3T3 cells which strongly depended on the mode of the fibers manufacturing. The study presents a comprehensive approach to toxicity assessment of textile fibers modified with NMs. Proposed approach may form a good “starting point” for improved future testing strategies.

Glasses showing catalytic effect have been of much interest recently because the catalytic layer is very effective in reducing of pollutants. The use of these glasses may bring reduction in cleaning costs. There are several methods of preparation of TiO2 with good catalytic properties, but sol-gel technique offers an opportunity to enhance catalytic effect by precise optimization of the composition and microstructure of the layer. This study concerns optimization of the composition and preparation technology of catalytic layers based on SiO2-TiO2 system. Catalytic effect was studied using Rhodamine B as a sensor. UV-VIS and photoelectron spectroscopy were the main research tools used in this study.

Published version. Source at http://doi.org/10.1371/journal.pone.0164779. License CC BY 4.0. Background Acute cough and lower respiratory tract infections (LRTIs) are one of the most important causes of lost working hours. Aim to explore variation and predictors in family practitioners (FPs) advice to patients with LRTIs about taking time off work in different European countries. Methods Prospective observational study in primary care networks in 12 countries, with multilevel mixed-effects binomial logistic regression. Results 324 FPs recruited 1616 employed adults who presented to primary care with LRTIs. The proportion of patients advised to take time off work varied from 7.6% in the Netherlands to 89.2% in Slovakia, and of these, 88.2% overall were advised to stay off work for seven days or less. None of Finnish or Dutch patients were advised to take more than 7 days off, in contrast to 35.5% of Polish and 27.0% of Slovak patients. The strongest predictors of FPs’ advice about time off work were: patient symptoms interfering with normal activities (OR 4.43; P

Background The prevalence of chronic kidney disease is rising continuously. Cardiovascular disease is among leading causes of death and premature mortality of patients with chronic kidney disease. Even the earliest stages of chronic kidney disease are associated with higher risk of subsequent coronary heart disease. The aim of this study was to determine markers of increased risk of atherosclerosis in CKD. Methods The study group consisted of a total of 80 patients (20 patients with stage I/II CKD, 20 with stage III CKD, 20 stage IV CKD and 20 stage V/dialysis) and 24 healthy volunteers. Levels of proteins (osteoprotegerin, osteopontin, osteocalcin, matrix γ-carboxyglutamic acid protein, fetuin A, MMP-2, MMP-9, TIMP-1, TIMP-2) and biochemical parameters were measured to analyse their influence on atherosclerosis risk in CKD patients. Cardiac echocardiography was performed to assess structural integrity and function, presence of left ventricular hypertrophy and systolic and diastolic function dysfunction. Results This study shows that the prevalence of ventricular hypertrophy (95.3 %) and diastolic dysfunction (93.2 %) in CKD patients is high. Also E/E’ ratio was significantly higher (13.6 ± 4.4, p = 0.001), tricuspid insufficiency (27.3 in CKD I/II vs. 71.4 in CKD V, p = 0.016), contractile dysfunction (33.3 in CKD I/II vs. 78.9 in CKD V, p = 0.040), mitral valve calcification (0 in CKD I/II vs. 28.6 in CKD V, p = 0.044) and aortic valve calcification (0 in CKD I/II vs. 61.9 in CKD V, p = 0.0008) were significantly more frequent in patients with CKD stage V/dialysis than in other groups. Only MMP-2, MMP-2/TIMP-2 ratio and TIMP-1 differed significantly between groups. Conclusions This study shows high prevalence of ventricular hypertrophy and diastolic dysfunction in CKD patients. Contractile dysfunction, mitral and aortic valve calcification in HD patients were significantly more frequent than in patients with other CKD stages. Significantly increased levels of MMP-2, MMP-2/TIMP-2 ratio and lower TIMP-1 suggests that these factors may be involved in the pathogenesis of atherosclerosis in CKD patients.

Introduction Self-medication can contribute to the inappropriate use of antibiotics in respiratory tract infections (RTI). This phenomenon has not been well described, particularly in Poland. The aim of our study was to describe the prevalence of antibiotic self-medication for RTI, to explore factors influencing antibiotic use without prescription, and to determine the available sources of such antibiotics. Material and methods A self-administered questionnaire completed by patients presenting to family medicine clinics at Lodz and Wroclaw from 1(st) March to 15(th) May 2010. Results A total of 891 patients in ten clinics completed the survey (response rate, 89.1%). Overall, 41.4% (n = 369) of patients reported self-medication with an antibiotic for RTI. The most common reason for antibiotic self-medication was a belief that antibiotics treat the majority of infections, including influenza and influenza-like illnesses (43.9%; n = 162). The predominant sources of antibiotics for self-medication were antibiotics from previous prescriptions stored by the patient at home (73.7%, n = 272), those received from a pharmacy without prescription (13.5%; n = 50), or from family members and friends (12.7%; n = 47). Conclusions Antibiotic self-medication for RTI was common in this population. This may be due to the belief that the antibiotics treat the majority of infections. A recommendation to either ask patients to return unused antibiotics to the physician's office or to dispense antibiotics in the exact amount which is necessary for an individual course, as well as the targeted education of pharmacy personnel and the general population, appear to be justified.

In patients with human immunodeficiency virus (HIV) as well as in patients with hepatitis C virus (HCV) infection the impairment of neutrophil activity is observed. We decided to analyze how treatment with pegylated interferon-alfa (Peg-IFN-alfa) and ribavirin affects neutrophil function in HIV/HCV coinfected patients. The study group consisted of 18 patients with HIV/HCV coinfection, on combination antiretroviral treatment (cART), aged between 27 and 42 y (mean 33.1±4.5 y). At the beginning of treatment with Peg-IFN-alfa and ribavirin all patients had an undetectable HIV viral load, and CD4 T-cell counts higher than 350 cells/μL. At two time points, before and after 12 wk of treatment with Peg-IFN-alfa and ribavirin, we examined intracellular levels of reactive oxygen species (ROS), and expression of selected adhesion molecules on whole blood neutrophils, along with apoptosis and necrosis of these cells. These analyses were done with flow cytometry. During anti-HCV therapy undetectable HIV levels were maintained in all patients. Treatment with PEG-IFN-alfa and ribavirin resulted in increases in the expression of CD11b and CD18, and decreases of CD16 and CD62L. However, only the change in CD62L expression was statistically significant (p

In our investigation, V doped SiO2/TiO2 thin films were prepared on glass substrates by dip coating sol-gel technique. Chemical composition of the samples was studied by X-ray photoelectron spectroscopy (XPS). Transmittance of the samples was characterized using UV-VIS spectrophotometry. Subsequently band-gap energy (Eg) was estimated for these films. Powders obtained from sols were characterized by FTIR spectroscopy. It was found that vanadium decreases optical band gap of SSiO2/TiO2 films.

The role of neutrophils in the pathogenesis of chronic hepatitis C as well as the effect of pegylated interferon α (PEG-IFN-α) and ribavirin treatment on neutrophil function is not precisely known. The study included 32 patients with CCH aged between 19 and 58 years (mean 33.5 years). Before and after 12 weeks of treatment with Peg-IFN-α and ribavirin, intracellular reactive oxygen species (ROS) level, expression of adhesion molecules CD11b/MAC-1, CD16, CD18 and CD62L on neutrophils, as well as apoptosis and necrosis of these cells were analyzed with the use of flow cytometry. During antiviral therapy, a statistically significant decrease of mean fluorescence intensity for CD16 high and CD62 and increase for CD11b/MAC-1 along with the increased apoptosis and decreased necrosis of neutrophils were observed. After 12 weeks of treatment, intracellular ROS production by unstimulated neutrophils did not change, but after stimulation with phorbol 12-myristate 13-acetate, statistically significant increase of ROS level was observed. During PEG-IFN-α and ribavirin treatment, activation of neutrophil function and increased ROS production were reported, which possibly resulted in accelerated apoptosis of these cells.

Glasses of different matrix (phosphate, borate, silicate and lead-silicate) were studied for their optical properties. The effect of Er dopant on transmittance and luminescence properties was presented. The significant “red shift” and “blue shift” of UV edge absorption were discussed based on the changes in the framework of the borate and phosphate glasses, respectively. It was showed that the integral intensity of the two main optical absorption transitions monotonically increases with the order: phosphate 3+ was discussed.

Early oxidation of unmodified and yttrium-implanted or chromium-implanted β-NiAl intermetallic compound at 1473 K was studied using a combination of two-stage-oxidation exposure with 18 O 2 as a tracer, SIMS elemental distribution analysis (depth profiling and imaging modes) and photoluminescence spectroscopy analysis of the scale phase composition. It was found that phase transformation of transient aluminium oxides, represented by 6- Al 2 O 3 into stable and protective α-Al 2 O 3 occurs locally and is affected by implanted additions: Yttrium retarded while chromium appeared to accelerate it. Typical patch- and/or web-like scale morphology of the growing scales was observed.

Hybrid glasses based on tetraethoxysilane (TEOS) modified by addition of selected cyclosiloxanes have been prepared by sol–gel method. Octamethylcyclotetrasiloxane (D4) and 2,4,6,8-tetramethyl-2,4,6,8-tetravinylsiloxane (VMC) have been chosen as an organic modifier of the silica matrix. Molar ratio of TEOS to cyclosiloxane varied from 1:0 to 1:0.5. Structure of prepared hybrids has been studied by infrared spectroscopy (FTIR), photoelectron spectroscopy (XPS) and nuclear magnetic resonance spectroscopy (NMR). Optical properties of bulk glasses in the visible range have also been reported.

The effects of Pt addition (5, 10 and 15 at.%) on the high temperature oxidation behaviour of the intermetallic compound β-NiAl were studied at 1150°C under both isothermal and thermal cycling conditions. The scale growth mechanism was assessed using two-stage oxidation exposures with 18O2 as a tracer in conjunction with high-resolution secondary ion mass spectrometer analysis of isotopic distributions. The scale morphologies were further characterized using secondary electron microscopy, Pt was found to reduce slightly the scale growth rate and improve considerably its resistance to spallation but it did not affect the sequence of scale development. Instead, it slowed the rate at which the scale developed. The α-Al2O3 scales that were eventually established were duplex in structure, consisting of a compact inner layer and a thinner outer layer. This outer layer consisted of ridges and grew by the coarsening of these and/or by a dislocation climb mechanism.

Fe20Cr5Al-type alumina forming alloys are known as α alumina-forming materials at relatively high temperatures (≥1273 K). This paper reports on the oxidation mechanism of commercial and synthetic Fe20Cr5Al alloys, at a considerably lower temperature, 1123 K. Some of the alloys were implanted with oxygen or yttrium ions prior to the oxidation exposure.Two-stage-oxidation, secondary ion mass spectrometry, secondary electron microscopy and lowangle X-ray diffraction were used as experimental tools. Results showed that even prolonged exposures are not sufficient to ensure that the scale consists essentially of α-Al2O3. Mechanisms involved from the observed scale morphology, microstructure and phase composition are discussed

Coating the material with a layer of carbon nanotubes (CNTs) has been a subject of particular interest for the development of new biomaterials. Such coatings, made of properly selected CNTs, may constitute an implantable electronic device that facilitates tissue regeneration both by specific surface properties and an ability to electrically stimulate the cells. The goal of the presented study was to produce, evaluate physicochemical properties and test the applicability of highly conductible material designed as an implantable electronic device. Two types of CNTs with varying level of oxidation were chosen. The process of coating involved suspension of the material of choice in the diluent followed by the electrophoretic deposition to fabricate layers on the surface of a highly biocompatible metal—titanium. Presented study includes an assessment of the physicochemical properties of the material’s surface along with an electrochemical evaluation and in vitro biocompatibility, cytotoxicity and apoptosis studies in contact with the murine fibroblasts (L929) in attempt to answer the question how the chemical composition and CNTs distribution in the layer alters the electrical properties of the sample and whether any of these properties have influenced the overall biocompatibility and stimulated adhesion of fibroblasts. The results indicate that higher level of oxidation of CNTs yielded materials more conductive than the metal they are deposited on. In vitro study revealed that both materials were biocompatible and that the cells were not affected by the amount of the functional group and the morphology of the surface they adhered to.