Sol–gel synthesis of ZnO–SiO2 thin films: impact of ZnO contents on its photonic efficiency

Highly crystalline ZnO–SiO₂ films obtained by a sol–gel method at different ZnO contents were deposited on silicon substrate (P(100)) using spin coating process. The XRD results revealed that the strong ZnO(100) peak is grown with highly c-axis oriented film and the crystallinity is progressively improved with increasing ZnO contents. SEM micrographs of the films deposited on silicon substrate show a homogeneous and uniformity structure at different ZnO content. The prepared ZnO–SiO₂ films are compared with either a film prepared from a commercial photocatalysts Hombikat UV-100 or Pilkington Glass Activ? by the determination of their photonic efficiencies for degradation of methylene blue. The photocatalytic efficiency of the 10 wt% ZnO–SiO₂ film was found to be about four times higher than film prepared from UV-100 or Pilkington Glass Activ?. The photocatalytic efficiencies of ZnO–SiO₂ films are increased with increasing ZnO content from 1 wt% to 10 wt% ZnO and then decreased at 15 wt% ZnO. The order of photocatalytic efficiencies of ZnO–SiO₂ films at different ZnO content and commercial photocatalysts after 6 h illumination were as following: 10 wt% ZnO > 15 wt% ZnO > 1 wt% ZnO > as-prepared 10 wt% ZnO–SiO₂ film > UV-100 > Pilkington Glass Activ?, which suggested that the ZnO–SiO₂ films are photoactive than commercial photocatalysts. The improved efficiency and potentially the low-cost synthesis suggest that this material might be practically useful as a photocatalyst film.     

Overexpression,Purification and Validation of Antigenic Salmonella enterica Serovar Typhi Proteins Identified from LC-MS/MS

In our earlier study, an immunoblot analysis using sera from febrile patients revealed that a 50-kDa band from an outer membrane protein fraction of Salmonella enterica serovar Typhi was specifically recognized only by typhoid sera and not sera from other febrile illnesses. Here, we investigated the identities of the proteins contained in the immunogenic 50-kDa band to pinpoint antigens responsible for its immunogenicity. We first used LC-MS/MS for protein identification, then used the online tool ANTIGENpro for antigenicity prediction and produced recombinant proteins of the lead antigens for validation in an enzyme-linked immunosorbent assay (ELISA). We found that proteins TolC, GlpK and SucB were specific to typhoid sera but react to antibodies differently under native and denatured conditions. This difference suggests the presence of linear and conformational epitopes on these proteins.     

Oleate Ester-Derived Nonionic Surfactants: Synthesis and Cloud Point Behavior Studies

The synthesis and cloud point behavior of high oleate ester-derived nonionic surfactants are now reported. The effect of various polyethoxylate chain lengths (polyethylene glycol with 7, 11, and 16 units of ethylene oxide (EO) monomer) as the surfactant's hydrophilic head on the cloud point was investigated. The effect of varying amounts of sodium chloride and five different ionic surfactants on the cloud points of the synthesized nonionic surfactants were also presented. When the chain length of polyethoxylate increased, the cloud point of the synthesized nonionic surfactant also increased, ranging from 16°C, 43°C, and 64°C for 7, 11, and 16 EO units, respectively. Increments in sodium chloride concentration depressed the cloud point values of the synthesized nonionic surfactants linearly. The addition of ionic surfactants elevated the cloud points of the synthesized nonionic surfactant. However, in the presence of sodium chloride, the cloud point of the mixed ionic-nonionic solution was suppressed and anincrease in ionic surfactant concentration was required to elevate the cloud point. It was also found that the cloud points of synthesized surfactants can be raised up to 95°C in the presence of 4wt% NaCl solution.     

Gamma-ray spectrometry for the self-attenuation correction factor of the sand samples from Antalya in Turkey

In this paper, we attempt to determine the self-attenuation correction factor for 37 different sand samples collected from Antalya region of Turkey with densities changing from 2.205 to 2.679 g  \(\hbox {cm}^{-3}.\) Transmission method has been used in order to obtain self-attenuation correction factor in comparison with the air and ultrapure water samples for each case. Self-attenuation correction factor versus energy fit curve is obtained. While the self-attenuation correction factor has large values at low energies, it becomes smaller at high energies and tends to become constant thereafter.     

Peleg and Weibull models for water absorption of copolymer gels crosslinked on polyethylene glycol dimethacrylates

In this study, the super-absorbent copolymer gels were obtained from the aqueous solution of monomers dispersed in a continuous organic phase. The inverse suspension polymerization was accomplished with the use of aqueous solutions of partly neutralized acrylic acid with a predetermined crosslinker agent, polyethylene glycol dimethacrylates (PEGDMA)/monomer ratio in cyclohexan. The copolymer gels synthesized using PEGDMA crosslinker with three different molecular weights (PEGDMA₃₃₀, PEGDMA₅₅₀, and PEGDMA₇₅₀) were characterized by ?nfrared spectroscopy and scanning electron microscopy. Water absorption capacities of the copolymer gels were determined. The water absorption capacity of 1 g copolymer gels in water was respectively obtained as 232, 255, and 316 g water/g polymer gel for PEGDMA₃₃₀, PEGDMA₅₅₀, and PEGDMA₇₅₀, respectively. The Peleg and Weibull models were used to describe the water absorption behavior of the copolymer gels. The highest values of R ² and the lowest values of χ ² and RMSE for copolymer gels were observed with the Weibull model.     

Electroanalysis of Benazepril Hydrochloride Antihypertensive Drug Using an Ionic Liquid Crystal Modified Carbon Paste Electrode

Electroanalysis of benazepril HCl was successful using a carbon paste electrode modified with an ionic liquid crystal ( 1‐butyl‐1‐methylpiperidinium hexafluorophosphate) in presence of sodium dodecyl sulfate. The electrode performance was compared to ionic liquids (1‐n‐hexyl‐3‐methyl imidazolium tetrafluoroborate and 1‐butyl‐4‐methyl pyridinium tetrafluoroborate). Electrochemical determination of benazepril HCl was in the linear dynamic range of 8.89×10^?7 to 1.77×10^?5 mol L^?1 (correlation coefficient 0.999) and LOD 7.17×10^?9 mol L^?1. benazepril HCl was determined using this sensor in presence of urine metabolites such as uric acid, ascorbic acid. Binary mixtures of dopamine/benazepril and amlodipine/benazepril were also determined successfully.     

Fabrication of an Electrochemical E. coli Biosensor in Biowells Using Bimetallic Nanoparticle‐Labelled Antibodies

An electrochemical biosensor was developed for the determination of Escherichia coli (E. coli) in water. For this purpose, silver‐gold core‐shell (Ag@Au) bioconjugates and anti‐E. coli modified PS‐microwells were designed in a sandwich‐type format in order to obtain higher sensitivity and selectivity. Ag@Au bimetallic nanoparticles were synthesized by co‐reduction method. The core‐shell formation was analyzed by using UV‐Vis spectroscopy and transmission electron microscopy. Biotin labeled anti‐E. coli antibodies were coupled with Ag@Au nanoparticles to form bioconjugates. The electrochemical immunosensor was prepared by immobilizing anti‐E. coli on polystyrene (PS)‐microwells via chemical bonding. These modified microwells were identified with X‐ray photoelectron spectroscopy and surface enhanced Raman spectroscopy. E. coli was sandwiched between Ag@Au bioconjugates and anti‐E. coli on PS‐microwells at different concentrations. The relationship between the E. coli concentration and stripping current of gold ions (Au³⁺) were investigated by square wave anodic stripping voltammetry at pencil graphite electrode. The proposed method can provide some advantages such as lower detection limit and shorter detection time. The electrochemical response for the immunosensor was linear with the concentration of the E. coli in the range of 10¹ and 10⁵ cfu/mL with a limit of detection 3 cfu/mL. The procedure maintains good sensitivity and repeatability and also offers utility in the fields of environmental monitoring and clinical diagnosis.     

PC expansion for material parameters using artificial data and statistical methods

This paper investigates the uncertainty of a hyper-elastic model by random material parameters as stochastic variables. For its stochastic discretization a polynomial chaos (PC) is used to expand the coefficients into deterministic and stochastic parts. Then, from experimental data in combination with artificial data for elastomers the distribution of the force-displacement curves are known. In the numerical example the PC-based stochastic and the deterministic parameter identification are used for generation of the distribution of Ogden's material parameters. (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Elastic moduli and step-like elastic anomalies in Ce-substituted Tl0.9Bi0.1Sr2−xCexCa0.9Y0.1Cu1.99Fe0.01O7−δ (x = 0–0.20) superconductors

Ultrasonic velocity measurements have been performed on polycrystalline Tl_0.9Bi_0.1Sr_2?xCe_xCa_0.9Y_0.1Cu_1.99Fe_0.01O_7?δ superconductor to study the influence of Ce substitution on elastic properties of the samples. Ce was observed to influence elastic moduli at 80 K which showed the largest value obtained at x = 0.10 where, coincidentally, the highest superconducting temperature T_c among samples was also shown. A longitudinal velocity anomaly was observed at around 260 K for the unsubstituted sample (x = 0). Ce substitution caused the temperature of the elastic anomaly to shift to 250 K (x = 0.1) and 262 K (x = 0.2). The existence of the step-like elastic anomaly was suggested to be due to oxygen ordering taking place in Tl–O planes. The analysis of elastic behavior in the vicinity of the elastic anomalies using the Landau free-energy model suggests that the anomaly is due to a phase transition which involves oxygen ordering.