Cobalt-free small La 3+ -doped BaFeO 3Àd is synthesized and systematically characterized towards application as an oxygen reduction electrode material for intermediate temperature solid oxide fuel cells (IT-SOFCs) with oxygen-ion conducting electrolyte. The formation of an oxygen vacancy-disordered perovskite oxide with cubic lattice symmetry is demonstrated by XRD, after the doping of only 5 mol% La 3+ into BaFeO 3Àd parent oxide with the formation of Ba 0.95 La 0.05 FeO 3Àd (BLF). The structural, thermal, electrical and electrochemical properties of BLF have been evaluated. High structural stability, high thermal expansion coefficient, high oxygen vacancy concentration, and relatively low electrical conductivity, are demonstrated. BLF shows a superior electrocatalytic activity, which is comparable to those state-of-the-art cobalt-based mixed conducting cathodes, in addition, it demonstrates a favorable long-term operational stability. It thus promises as a new cathode candidate for IT-SOFCs with oxygen-ion conducting electrolyte.

The adsorption and thermal reactions of 2-iodoethanol on clean Ni(100) single-crystal surfaces were studied by temperature-programmed desorption (TPD) and X-ray photoelectron spectroscopy (XPS). 2-Iodoethanol was chosen as a precursor for the preparation of 2-hydroxyethyl and oxametallacycle surface species, potential intermediates in hydrocarbon catalytic oxidations. It was found that 2-iodoethanol adsorbs molecularly at 100 K, in two configurations involving either just the iodine atom or both iodine and hydroxyl ends of the molecule. A complex chemical behavior starts around 140 K with the production of small amounts of ethylene and water, most likely via the concerted decomposition or disproportionation of the adsorbed molecular species. The bulk of the 2-iodoethanol decomposes at about 150 K via an initial carbon−iodine scission to form −O(H)CH2CH2− (∼80%) and 2-hydroxyethyl (∼20%) intermediates. Two competing reactions are involved with the subsequent conversion of the 2-hydroxyethyl species around 160 K, a reductive elimination with surface hydrogen to yield ethanol, and a β−H elimination to surface vinyl alcohol. The −O(H)CH2CH2−, on the other hand, dehydrogenates to a −OCH2CH2− oxametallacycle species about the same temperature. Both 2-hydroxyethyl and the oxametallacycle species tautomerize to acetaldehyde, around 210 K and above 250 K, respectively, and some of that acetaldehyde desorbs, whereas the rest decomposes to hydrogen and carbon monoxide. The implications of this chemistry to catalysis are discussed.

An aptamer screening method using a positive and negative selection units integrated microfluidic chip was introduced. Here, myoglobin (Myo), one of the early markers to increase after acute myocardial infarction, was used as the model. After 7-round selection, the aptamers, which exhibited dissociation constants (K(d)) in the nanomolar range (from 4.93 to 6.38 nM), were successfully obtained using a positive and negative selection units integrated microfluidic chip. The aptamer with the highest affinity (K(d) = 4.93 nM) was then used for the fabrication of a label-free supersandwich electrochemical biosensor for Myo detection based on target-induced aptamer displacement. The detection limit of this aptamer-based electrochemical biosensor was 10 pM, which was significantly lower than that of those previous antibody-based biosensors for Myo detection. This work may not only develop a strategy for screening aptamer but also offer promising alternatives to the traditional analytical and immunological methods for Myo detection.

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A simple assay for multiplex DNA detection has been developed using a microfluidic chip and a personal glucose meter. By using this system, multiplex detection of three genotypes of hepatitis B virus DNA was possible with a detection limit of 10 pM. This point-of-care assay represented a versatile platform for sensitive multiplex target detection.

Background: Tumor vessels can potentially serve as diagnostic, prognostic and therapeutic targets for solid tumors. Fluorescent dyes are commonly used as biological indicators, while photobleaching seriously hinders their application. In this study, we aim to generate a fluorescent silica nanoparticles (FSiNPs) theranostic system marked by the mouse endgolin (mEND) aptamer, YQ26.Methods: A highly specific YQ26 was selected by using gene-modified cell line-based SELEX technique. FSiNPs were prepared via the reverse microemulsion method. The YQ26-FSiNPs theranostic system was developed by combining YQ26 with the FSiNPs for in vivo tumor imaging, treatment and monitoring.Results: Both in vitro experiments (i.e. cellular and tumor tissue targeting assays) and in vivo animal studies (i.e. in vivo imaging and antitumor efficacy of YQ26-FSiNPs) clearly demonstrated that YQ26-FSiNPs could achieve prominently high targeting efficiency and therapeutic effects via aptamer YQ26-mediated binding to endoglin (END) molecule.Conclusion: This simple, sensitive, and specific YQ26-FSiNPs theranostic system has a great potential for clinical tumor targeting imaging and treatment.

The thermal chemistry of 1-chloro-2-methyl-2-propanol (CH2Cl(CH3)2COH) on a Ni(100) single-crystal surface, clean and after hydrogen preadsorption, was studied by temperature-programmed desorption and X-ray photoelectron spectroscopy. The 1-chloro-2-methyl-2-propanol adsorbs molecularly on the metal surface at 100 K. An initial chemical reaction is seen at around 180 K involving the sequential scission of the C−Cl and O−H bonds to produce hydroxyalkyl −CH2(CH3)2COH and oxametallacycle −CH2(CH3)2CO− intermediates. Hydrogenation of the first surface species produces tert-butyl alcohol, whereas further conversion of the oxametallacycle follows at least three reaction pathways, a cyclization to isobutene oxide, a hydrogenation to tert-butyl alcohol, and a dehydration reaction to produce isobutene, water, H2, and CO. It was also shown that hydrogen coadsorption on the surface enhances the production of tert-butyl alcohol and partially inhibits the decomposition to isobutene.