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Mesoporous NiO samples with different morphology were synthesized by hydrothermal method, and they were studied as electrocatalysts for oxygen evolution reaction in alkaline solution. The NiO samples were characterized by X-ray diffraction, transmission electron microscopy, N-2-adsorption, scanning electron microscopy and X-ray photoelectron spectroscopy. The critical synthesis parameters like hydrothermal reaction temperature, time and molar ratio of precursors were varied using Taguchi experimental method to investigate their effect on morphology and specific surface area of mesoporous NiO samples. The characterization data illustrated the formation of nanoplates, nanorods, and nanoparticles. All the NiO samples exhibited mesoporosity and the specific surface area values in the range of 88-156 m(2)/g. One of the synthesized mesoporous NiO samples, largely constituting of nanoplates and nanorods with high porosity, exhibited a Tafel slope of 62 mV/dec and achieved a current density of 41.6 mA/cm(2) at 1.6 V (vs. RHE). It showed better electrocatalytic activity for oxygen evolution reaction than remaining samples. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Nanoporous materials with core-shell structure have received lots of attention owing to the great versatility of the functional cores and shells and their potential application in catalysis and biological applications. In this work, a facile method has been developed to synthesize uniform Au@Pt@mesoporous SiO2 nanostructures with high peroxidase-like activity, which had a well-defined core–shell structure with Au nanorods@Pt nanodots as a core and mesoporous SiO2 as a shell. The mesoporous SiO2 shell can not only provide convenient transmission channels but offer a substantial location for accommodation of large biomolecules, such as antibodies and antigens. Here a novel nanoprobe based on Au@Pt@mesoporous SiO2 nanozyme modified with mumps antigens was reported. Notably, the encapsulation of Au@Pt nanorod in mesoporous SiO2 shell was able to hinder the interaction between catalytical nanoparticles and recognition antigens, retaining the catalytic activity of the inner active nanoparticle core. Furthermore, this nanoprobe exhibited an extraordinarily stability and showed excellent activity. As a result, we presented an enzyme linked immunosorbant assay (ELISA) for the diagnosis of mumps virus; this proposed method exhibited good sensitivity to mumps-specific IgM antibodies. The limit of detection can be as low as 10 ng/mL, which was more sensitive compared to the conventional immunoassay. Our results indicated that this nanoprobe hold great promise with opportunities for applications of biosensors, catalysis and biotechnology.

The global challenge to the treatment of malaria is mainly the occurrence of resistance of malaria parasites to conventionally used antimalarials. Artesunate, a semisynthetic artemisinin compound, and other artemisinin derivatives are currently used in combination with selected active antimalarial drugs in order to prevent or delay the emergence of resistance to artemisinin derivatives. Several methods, such as preparation of hybrid compounds, combination therapy, chemical modification and the use of synthetic materials to enhance solubility and delivery of artesunate, have been employed over the years to improve the antimalarial activity of artesunate. Each of these methods has advantages it bestows on the efficacy of artesunate. This review discussed the various methods employed in enhancing the antimalarial activity of artesunate and delaying the emergence of resistance of parasite to it.

peer-reviewed Antibiotic resistance and the shortage of novel antimicrobials are among the biggest challenges facing society. One of the major factors contributing to resistance is the use of frontline clinical antibiotics in veterinary practice. In order to properly manage dwindling antibiotic resources, we must identify antimicrobials that are specifically targeted to veterinary applications. Nisin is a member of the lantibiotic family of antimicrobial peptides that exhibit potent antibacterial activity against many gram-positive bacteria, including human and animal pathogens such as Staphylococcus, Bacillus, Listeria, and Clostridium. Although not currently used in human medicine, nisin is already employed commercially as an anti-mastitis product in the veterinary field. Recently we have used bioengineering strategies to enhance the activity of nisin against several high profile targets, including multi-drug resistant clinical pathogens such as methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) and also against staphylococci and streptococci associated with bovine mastitis. However, newly emerging pathogens such as methicillin resistant Staphylococcus pseudintermedius (MRSP) pose a significant threat in terms of veterinary health and as a reservoir for antibiotic resistance determinants. In this study we created a nisin derivative with enhanced antimicrobial activity against S. pseudintermedius. In addition, the novel nisin derivative exhibits an enhanced ability to impair biofilm formation and to reduce the density of established biofilms. The activities of this peptide represent a significant improvement over that of the wild-type nisin peptide and merit further investigation with a view to their use to treat S. pseudintermedius infections. This work was supported by the Irish Government under the National Development Plan, through Science Foundation Ireland Investigator awards (10/IN.1/B3027 (http://www.sfi.ie). DF would like to acknowledge receipt of a Society for Applied Microbiology (http://www.sfam.org.uk) Students into Work Grant for FL.

This paper presents a catalytic, spectroscopic, calorimetric study of mildly steam-dealuminated mordenite (H-MOR). With increasing steam partial pressures at 673 K there is increasing dealumination, the loss of Brønsted acid sites and the presence of extra-framework Al (AlEF) likely in the zeolite pores. Additionally, the number of Lewis sites increases with increasing AlEF. As observed in previous studies, the catalytic activity for hydroisomerization of n-hexane and monomolecular cracking of n-butane and n-hexane initially increases and goes through a maximum with increasing steam severity. While the maximum increase in the rate of hexane cracking is about 5 times, the activation energies indicate that steaming does not significantly change the strength of the Brønsted acid sites. In the absence of AlEF, the enthalpy of alkane adsorption is constant at all surface coverages. However, in the presence of AlEF, the initial heat of alkane sorption increases by about 5–10 kJ/mol. After covering these adsorption sites, the heat of adsorption is identical to that on the unsteamed H-MOR until saturation coverage has been reached. The increased enthalpies of adsorption are suggested to occur on the AlEF, Lewis acid sites. Since the surface coverage of paraffins under typical reaction conditions is low, it is proposed that the enhanced rate is due to the increased initial heat of adsorption leading to a higher concentration of reactants in the steamed H-MOR zeolites.

High surface area carbon supported Pt and Pt3Sn catalysts were synthesized by microwave irradiation and investigated in the ethanol electro-oxidation reaction. The catalysts were obtained using a modified polyol method in an ethylene glycol solution and were characterized in terms of structure, morphology and composition by employing XRD, STM and EDX techniques. The diffraction peaks of Pt3Sn/C catalyst in XRD patterns are shifted to lower 2 theta values with respect to the corresponding peaks at Pt/C catalyst as a consequence of alloy formation between Pt and Sn. Particle size analysis from STM and XRD shows that Pt and Pt3Sn clusters are of a small diameter (similar to 2 nm) with a narrow size distribution. Pt3Sn/C catalyst is highly active in ethanol oxidation with the onset potential shifted for similar to 150 mV to more negative values and with similar to 2 times higher currents in comparison to Pt/C.

Gold catalysts with loading 1 and 10 wt % were-prepared by deposition precipitation method with urea over mesoporous manganese oxide, obtained through a surfactant-assisted procedure by using cetyltrimethylammonium bromide (CTAB), followed by treatment with sulphuric acid. For comparison, Au(10 wt %) was also deposited over commercial CeO2 and SiO2 supports. The materials were characterized by XRD and EXAFS at the Mn K and Au L-III edges and XPS. Moreover, the analyses were performed on the samples treated under 1%CO/He, at 250 degrees C for 90 min. The structural and surface results of the as prepared manganese oxide confirmed the formation of gamma-MnO2 along with some amorphous Mn3O4 upon treatment of the precursor oxide with sulphuric acid. The CO treatment induces the formation of reduced phases, Mn3O4 (Hausmannite) and Mn2O3 (Bixbyite). Gold particles have a positive effect in promoting the reduction of manganese oxide and this effect is more pronounced in the Au(10 wt %) catalyst, which exhibits an enhanced CO oxidation activity with respect to both the Au(1 wt %) sample and the metal-free manganese oxide. The higher efficiency of Au(10 wt %) catalyst is attributed to a strong metal-support interaction between gold nanoparticles and support, as demonstrated by the presence of a component Au-O at 2.1 angstrom in the Fourier transform of the EXAFS signal of both the fresh and the CO-treated samples.

We present a new procedure for the site-specific deposition of metal on semiconductor nanofibers (NF). The semiconductor NFs are exposed to an external electric field while irradiated with UV light. This coupling allows the generation of excited electron–hole couples and drives them to the opposite extremities of the fibers where they can react with redox species in solution. We demonstrate here that, when both UV light and electric field are simultaneously applied, a metal deposit is formed at the cathodically polarized tip of the NF in a controlled way. Such an electric-field-assisted photochemical (EFAP) process is suitable for highly localized photodeposition of metals, leading to semiconductor Janus objects.