Spatial distribution of reaction products in direct ethanol fuel cell

The electro-catalytic oxidation of ethanol in a direct-type polymer electrolyte membrane fuel cell is known to be more complex than that of methanol. We used both solution and solid-state nuclear magnetic resonance (NMR) methods for the first time to successfully identify and quantify the reaction intermediates and the fuel itself which were distributed differently over fuel pathways and the polymer membrane (PEM) in the direct ethanol fuel cell (DEFC). The diverse chemical species present in the exhaust were identified by high-resolution solution NMR, while the nature and amounts of the species in the PEM of the DEFC were analyzed by solid-state NMR. The relative amount of reaction intermediates of ethanol detected in the PEM was an order of magnitude higher than that observed in the exhaust, which might be of critical importance in understanding and developing DEFC systems.     

27Al Magic Angle Spinning Nuclear Magnetic Resonance Study of Al1−x Cr x K(SO4)2·12H2O (x = 0, 0.07, and 0.2)

The physical properties of Al_1?x Cr _x K(SO₄)₂·12H₂O (x = 0, 0.07, and 0.2) were studied as a function of temperature using magic angle spinning nuclear magnetic resonance for ²⁷Al. On the basis of the physical properties of pure AlK(SO₄)₂·12H₂O, the effects of partially replacing Al³⁺ with Cr³⁺ ions were examined. Molecular motion changed with the concentration of Cr³⁺ ions. The relaxation process near 320 K was found to undergo molecular motion as described by the Bloembergen–Purcell–Pound theory. The activation energies, phase transition temperatures, and spin–lattice relaxation times in the rotating frame T _1ρ changed with the concentration of paramagnetic ions.     

Barium Sodium Niobate Powders and Thin Films: Preparation and Ferroelectric Behavior

Powders and thin films of barium sodium niobate, Ba₄Na₂Nb₁₀O₃₀, of filled tungsten bronze type ferroelectric were processed by a sol-gel route using barium metal, niobium ethoxide and sodium methoxide as precursors. Polycrystalline powder resulted after heat treating the gel powder at or above 650°C. Thin films of Ba₄Na₂Nb₁₀O₃₀ showed no preferred orientation on Si(100), Pt/Si(100) and sapphire substrates. Hysteresis measurements at 1 kHz for the thin films annealed at 750°C, obtained using a prehydrolyzed precursor solution, and gave remanent polarization of 17.34 µC/cm² and coercive field of 62.5 kV/cm. Microstructural investigation of surface morphology of these films revealed grains about 0.3 µm in size. Prehydrolysis of the precursor solution was found to be necessary to achieve dense films with ferroelectric properties.     

Serum exosomal microRNAs as novel biomarkers for hepatocellular carcinoma

Recent studies have shown that circulating microRNAs are a potential biomarker in various types of malignancies. The aim of this study was to investigate the feasibility of using serum exosomal microRNAs as novel serological biomarkers for hepatocellular carcinoma (HCC) in patients with chronic hepatitis B (CHB). We measured the serum exosomal microRNAs and serum circulating microRNAs in patients with CHB (n=20), liver cirrhosis (LC) (n=20) and HCC (n=20). Serum exosomal microRNA was extracted from 500 μl of serum using an Exosome RNA Isolation kit. The expression levels of microRNAs were quantified by real-time PCR. The expression levels of selected microRNAs were normalized to Caenorhabditis elegans microRNA (Cel-miR-39). The serum levels of exosomal miR-18a, miR-221, miR-222 and miR-224 were significantly higher in patients with HCC than those with CHB or LC (P<0.05). Further, the serum levels of exosomal miR-101, miR-106b, miR-122 and miR-195 were lower in patients with HCC than in patients with CHB (P=0.014, P<0.001, P<0.001 and P<0.001, respectively). There was no significant difference in the levels of miR-21 and miR-93 among the three groups. Additionally, the serum levels of circulating microRNAs showed a smaller difference between HCC and either CHB or LC. This study suggests that serum exosomal microRNAs may be used as novel serological biomarkers for HCC.     

On Rescaled Poisson Processes and the Brownian Bridge

The process obtained by rescaling a homogeneous Poisson process by the maximum likelihood estimate of its intensity is shown to have surprisingly strong self-correcting behavior. Formulas for the conditional intensity and moments of the rescaled Poisson process are derived, and its behavior is demonstrated using simulations. Relationships to the Brownian bridge are explored, and implications for point process residual analysis are discussed.     

On Non-simple Marked Point Processes

Simple point processes are often characterized by their associated compensators or conditional intensities. Non-simple point processes are not uniquely determined by their conditional intensity and compensator, so instead one may identify with the point process its associated simple point process and corresponding conditional intensity, on an expanded mark space. Some relations between the conditional intensity on the expanded mark space and the ordinary conditional intensity are investigated here, and some classes of separable non-simple processes are presented. Transformations into simple point processes, involving thinning and rescaling, are presented.     

Reaction of diphenylcyclopropenethione with Mn(CO)5−: Ring cleavage,alkylation, and reduction

Alkylation, reduction, and ring opening of diphenylcyclopropenethione to a π-allyl complex occurs on treatment with Mn(CO)₅^? and methyl iodide in aqueous methanol.     

Real-time analysis of enzymatic surface-initiated polymerization using surface plasmon resonance (SPR)

The kinetics of enzymatic surface-initiated polymerization of PHB on gold surface has been examined by SPR and the resultant polymer layers characterized by AFM and FT-IR spectrometry. The immobilized enzyme catalyzed surface-initiated polymerization of 3HB-CoA, resulting in the formation of a polymer brush on the surface. The rate of polymer growth from the surface was monitored by SPR in real-time. Polymer growth as measured by the increase in the resonance angle showed no apparent lag phase during the polymerization reaction. SPR analysis also revealed that the thickness of the polymer film could be controlled by varying the initial enzyme density on the surface. The average thicknesses of the PHB film after polymerization reaction were 95, 45 and 15 nm for the surfaces that were treated with 0.5, 0.3 and 0.1*10(-6) M of enzyme, respectively. The binding of PHA synthase at different concentration to the mixed SAMs and subsequent polymerization.