Abstract: A series of perovskites Sr4−xLaxFe3ReO12 (x=0.0, 1.0, 2.0) has been prepared by wet chemistry methods. The structure analyses by powder X-ray and neutron diffraction and electron microscopy show that these compounds adopt simple perovskite structures without cation ordering over the B sites: tetragonal (I4/mcm) for x=0.0 and 1.0 and orthorhombic (Pbmn) for x=2.0. The oxidation states of the cations in the compound with x=0.0 appear to be Fe3+/4+ and Re7+ and decrease for both with La substitution as evidenced by X-ray absorption spectroscopy. All the compounds are antiferromagnetically ordered above room temperature, as demonstrated by Mössbauer spectroscopy and the magnetic structures, which were determined by powder neutron diffraction. The substitution of Sr by La strongly affects the magnetic properties with an increase of TN up to ∼750 K.

Abstract: Pristine and oxygen plasma functionalised carbon nanotubes (CNTs) were studied after the evaporation of Pt and Pd atoms. High resolution transmission electron microscopy shows the formation of metal nanoparticles at the CNT surface. Oxygen functional groups grafted by the plasma functionalization act as nucleation sites for metal nanoparticles. Analysis of the C1s core level spectra reveals that there is no covalent bonding between the Pt or Pd atoms and the CNT surface. Unlike other transition metals such as titanium and copper, neither Pd nor Pt show strong oxygen interaction or surface oxygen scavenging behaviour.

Abstract: We present the use of computational fluid dynamics (CFD) for accurately determining the adsorption parameters of acetaldehyde on photocatalytic fiber filter material, integrated in a continuous flow system. Unlike the traditional analytical analysis based on Langmuir adsorption, not only steady-state situations but also transient phenomena can be accounted for. Air displacement effects in the reactor and gas detection cell are investigated and inherently made part of the model. Incorporation of a surface aldol condensation reaction in the CFD analysis further improves the accuracy of the model which enables to extract precise, intrinsic adsorption parameters for situations in which analytical analysis would otherwise fail.

Abstract: (Sun)Light is an abundantly available sustainable source of energy that has been used in catalyzing chemical reactions for several decades now. In particular, studies related to the interaction of light with plasmonic nanostructures have been receiving increased attention. These structures display the unique property of localized surface plasmon resonance, which converts light of a specific wavelength range into hot charge carriers, along with strong local electromagnetic fields, and/or heat, which may all enhance the reaction efficiency in their own way. These unique properties of plasmonic nanoparticles can be conveniently tuned by varying the metal type, size, shape, and dielectric environment, thus prompting a research focus on rationally designed plasmonic hybrid nanostructures. In this review, the term “hybrid” implies nanomaterials that consist of multiple plasmonic or non-plasmonic materials, forming complex configurations in the geometry and/or at the atomic level. We discuss the synthetic techniques and evolution of such hybrid plasmonic nanostructures giving rise to a wide variety of material and geometric configurations. Bimetallic alloys, which result in a new set of opto-physical parameters, are compared with core–shell configurations. For the latter, the use of metal, semiconductor, and polymer shells is reviewed. Also, more complex structures such as Janus and antenna reactor composites are discussed. This review further summarizes the studies exploiting plasmonic hybrids to elucidate the plasmonic-photocatalytic mechanism. Finally, we review the implementation of these plasmonic hybrids in different photocatalytic application domains such as H2 generation, CO2 reduction, water purification, air purification, and disinfection.

Abstract: Sensitive multi-element analysis techniques were applied to water samples collected in the vicinity of a small Zn-Pb-Cu sulfide mineralization in the region of Menez-Albot (Finistère, France). The variation of the trace-element content along a local stream shows the presence of the mineralization, mainly through a simultaneous positive anomaly in solution for a group of about 10 elements (e.g. Ni, Cu, Zn, As, Sb) which are connected with this type of mineralization. The anomaly decreases steeply due to the influx of swamp water rich in Fe, Mn and organic matter. The precipitation barrier is reflected in the stream sediment composition. Contamination from fertilizers was observed in some samples.

Abstract: Spark-source mass spectrometric analyses of synthetic simulated biological samples were performed to determine the importance of matrix effects. A correlation between the variation of the relative sensitivity coefficients (RSC's) and the spark plasma composition, hence plasma temperature, was found. The determined RSC's were used in the analysis of four biological standard reference materials. An accuracy of 1013% and detection limits between 0.005 and 0.5 ppm were obtained during analysis under normal conditions.

Abstract: The nature of the low-temperature photochemical assisted formation process of ferroelectric lead titanate (PbTiO3) films is studied in the present work. Films are obtained by the deposition of an aqueous solution containing citric acid based (citrato) metal ion complexes with intrinsic UV activity. This UV activity is crucial for the aqueous photochemical solution deposition (aqueous PCSD) route being used. UV irradiation enhances the early decomposition of organics and results in improved electrical properties for the crystalline oxide film, even if the film is crystallized at low temperature. GATR-FTIR shows that UV irradiation promotes the decomposition of organic precursor components, resulting in homogeneous films if applied in the right temperature window during film processing. The organic content, morphology and crystallinity of the irradiated films, achieved at different processing atmospheres and temperatures, is studied and eventually correlated to the functional behavior of the obtained films. This is an important issue, as crystalline films obtained at low temperatures often lack ferroelectric responses. In this work, the film prepared in pure oxygen at the very low temperature of 400 degrees C and after an optimized UV treatment presents a significant remanent polarization value of P-r = 8.8 mu C cm(-2). This value is attributed to the better crystallinity, the larger grain size and the reduced porosity obtained thanks to the early film crystallization effectively achieved through the UV treatment in oxygen. (C) 2016 Elsevier B.V. All rights reserved.

Abstract: The adsorptive voltammetric behaviour of tinidazole onto the HMDE was investigated and validated in solubilized system and biological fluids by CV, SWCAdSV and DPCAdSV. Addition of CTAB to the solution containing drug enhanced the peak current while anionic and non-ionic surfactants showed an opposite effect. The electrode process is irreversible and adsorption controlled. Various chemical and instrumental parameters affecting the monitored electroanalytical response were investigated and optimized for tinidazole determination. Under optimized conditions; the adsorptive stripping peak current is linear over the concentration range 7.0 × 10−9 to 6.2 × 10−7 mol/L with detection limit of 4.5 × 10−10 mol/L. The precision of the proposed method in terms of RSD is 1.2% and mean recovery of 100.01%. The applicability of proposed method is further extended to in vitro determination of the drug in biological fluids.

Abstract: In this work an aptamer-based biosensor is combined with a multisine electrochemical impedance spectroscopy sensing methodology into a novel and promising biosensing strategy. Employing a multisine instead of a traditional single sine measuring method allows the detection and quantification of parameters that provide information about the accuracy and reliability of the results, such as noise and distortions. This does not only lead to a shorter measurement time, but it also enables an easy and fast evaluation of the quality of the data and fitting, leading to more accurate results.

Abstract: Shelf sediments of the southern North Sea, were studied with a microanalytical [electron probe X-ray microanalysis (EPXMA)] and two bulk [X-ray diffraction (XRD) and X-ray fluorescence (XRF)] techniques. The investigation proved that the promptness of the microanalytical method is combined with a reasonable analytical reliability. XRD studies of such a type of sediments with monotonous mineral composition are not able to provide mineralogical information beyond the main well-crystalline minerals and the mineralogical quantitative characteristic of the sediment based on XRD estimations are incorrect. The EPXMA mineralogical interpretations are based on the statistical evaluation of a huge data set (thousands of mineral particles) and provide a rather correct quantitative determination of the main minerals. The comparative EPXMAXRF study revealed that the Al, Si, K, Ca, Fe and to some extent Ti contents estimated by EPXMA are fairly reliable. In this respect the accuracy of the EPXMA-based mineral identification of the pure silicates, pure aluminosilicates, and Al-, Ca-, Fe- and Ti-containing minerals with simple composition is very high. Mg-calcite, augite and apatite determinations are assessed to be correct. The supposed accuracy of the clay mineral determinations is slightly lower (7080%) than that of the other main minerals due to the complex and varying composition of the clays. The identification of XRD-invisible accessory minerals and quantification of their presence in the sediments is an essential advantage of the EPXMA, which makes it a useful approach in tracing the origin of the sediments, the pathways of their transport and the geochemical processes they have undergone. However, the EPXMA has several flaws, which need to be solved in the future sediment investigations: (1) calibration with natural standards is needed in order to provide a higher accuracy of the mineral determinations; (2) any EPXMA study of sediments needs to be secured with XRF examinations of selected samples since EPXMA gives only semi-quantitative information about the abundance of the elements; (3) ultra-thin window EPXMA of low-Z elements has to be used since some of them (O, C) are always present in the main sediment components: silicates, aluminosilicates, carbonates and metal oxyhydroxides; (4) the interpretations of the clay fraction have to be supported with detailed XRD investigations of selected samples, while the mineralogy of the silt and sand fractions needs to be backed up with optical microscopy studies. The information from different analytical techniques (EPXMA with XRFXRD-optical microscopy of selected samples) combined with the knowledge about the most possible minerals in a given environment, would give the most reliable results in studying mineralogical composition of shelf sediments.

Abstract: Laser microprobe mass analysis (LAMMA) was applied to particulate matter from the Atlantic Ocean. Inferring information about the surface layer by LAMMA was not probe X-ray microanalysis (EPXMA). Geochemically relevant groups of particles had been identified by EPXMA and cluster analysis. For both locations, the most abundant ones appeared to be those rich in silicon and the alumino-silicates. Afterwards LAMMA was applied to obtain more information about the trace element composition and surface characteristics. The iron-rich phase appeared to contain significant amounts of heavy metals and of phosphate. Lead appeared to be associated in detectable amounts with alumino-silicates in the Scheldt but not with those in the Atlantic Ocean. Inferring information about the surface layer by LAMMA was not always unambiguous.