The role of the Boudouard and water–gas shift reactions in the methanation of CO or CO<inf>2</inf> over Ni/γ-Al<inf>2</inf>O<inf>3</inf> catalyst

The Boudouard and the water–gas shift reactions were studied at different temperatures between 453 and 490 K over a Ni/γ-Al$_2$O$_3$ catalyst in a Carberry batch reactor using various mixtures of CO, H$_2$ and CO$_2$. The activity of the Boudouard reaction was found to be low, compared to the water–gas shift reaction, and diminished over time, suggesting that the temperature was too low for significant activity after an initiation period of CO adsorption. Furthermore, the rate of the Boudouard reaction has been reported to decrease in the presence of H$_2$O and H$_2$. The water–gas shift reaction was found to be the main reaction responsible for the production of CO$_2$ in a mixture of CO, H$_2$ and H$_2$O in the batch reactor. The ratio of the total amount of CO consumed to the total amount of CO$_2$ produced showed that the catalyst was also active towards hydrogenation, where the rate of the hydrogenation reaction was very much faster than the water–gas shift reaction. The resulting ratio of $\textit{p}$$_{H_2}$ to $\textit{p}$$_{CO}$ was found to be extremely low, probably leading to the production of long-chain hydrocarbons. The stoichiometry of the overall reaction was such that for every mole of CO$_2$ produced, 1.5 mol of CO was consumed in the batch reactor. Kinetic studies were performed in the batch reactor. An Eley-Rideal mechanism was found to provide a good agreement with the experimental results over a wide range of partial pressures of steam and CO.JYL was funded by the Cambridge International Scholarship Scheme. The Cambridge Philosophical Society, the Lundgren Research Award and Corpus Christi College are also gratefully thanked for contributing to the support of his PhD studies. We are grateful for the assistance of Dr A.P.E. York, Johnson Matthey Technology Centre, Sonning Common, Reading RG4 9NH, United Kingdom, for his valuable input to this research.This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.ces.2016.06.04

Kinetics of the reduction of wüstite by hydrogen and carbon monoxide for the chemical looping production of hydrogen

Hydrogen of very high purity can be produced via the steam-iron process, in which steam oxidises metallic Fe in 3/4Fe + H2O→1/4Fe3O4 + H2. It is then advantageous to oxidise Fe3O4 in air to Fe2O3, an oxygen-carrier. This higher oxide of Fe is then reduced to regenerate metallic iron by reacting with synthesis gas, producing metallic Fe and possibly some wüstite (FexO, 0<x<1). In this three-stage process, the reduction of FexO to Fe is the slowest reaction. This paper is concerned with the kinetics of the reduction of wüstite (FexO) by reaction with CO, and, or H2. Starting with pure (99 wt%) wüstite, the intrinsic kinetics of its reduction to metallic iron were measured in fluidised beds at different temperatures. The reaction was found to have 3 distinct stages, (i) the removal of lattice oxygen in wüstite, (ii) rate increasing with conversion of solid and (iii) rate decreasing with conversion of solid. A random pore model was used to simulate the latter stages of the reduction of wüstite by either H2 or CO or a mixture of the two. It was found that the intrinsic rate of reduction in H2 is substantially faster than with CO, whereas the resistances to diffusion of H2 and CO through the product layer of Fe are comparable; these factors account for differences in the overall rates observed with these gases.This is the final published version. It is also available from the publisher at: http://www.sciencedirect.com/science/article/pii/S000925091400428X

A PDMS-Based 2-Axis Waterproof Scanner for Photoacoustic Microscopy

Optical-resolution photoacoustic microscopy (OR-PAM) is an imaging tool to provide in vivo optically sensitive images in biomedical research. To achieve a small size, fast imaging speed, wide scan range, and high signal-to-noise ratios (SNRs) in a water environment, we introduce a polydimethylsiloxane (PDMS)-based 2-axis scanner for a flexible and waterproof structure. The design, theoretical background, fabrication process and performance of the scanner are explained in details. The designed and fabricated scanner has dimensions of 15 × 15 × 15 mm along the X, Y and Z axes, respectively. The characteristics of the scanner are tested under DC and AC conditions. By pairing with electromagnetic forces, the maximum scanning angles in air and water are 18° and 13° along the X and Y axes, respectively. The measured resonance frequencies in air and water are 60 and 45 Hz along the X axis and 45 and 30 Hz along the Y axis, respectively. Finally, OR-PAM with high SNRs is demonstrated using the fabricated scanner, and the PA images of micro-patterned samples and microvasculatures of a mouse ear are successfully obtained with high-resolution and wide-field of view. OR-PAM equipped with the 2-axis PDMS based waterproof scanner has lateral and axial resolutions of 3.6 μm and 26 μm, respectively. This compact OR-PAM system could potentially and widely be used in preclinical and clinical applications. © 2015 by the authors; licensee MDPI, Basel, Switzerland.111513Ysciescopu

Synthesis of horizontally aligned ZnO nanowires localized at terrace edges and application for high sensitivity gas sensor

We developed step edge decoration method for the fabrication of semiconductor ZnO nanodots and nanowires using pulsed laser deposition. We synthesized high quality ZnO nanowires with the small diameter of about 20 nm and the uniform interval of about 80 nm between each nanowire, which has a simple structure for the formation of contact electrodes. The ZnO nanowire-based sensor was prepared only with the simple process of a gold electrode formation. The ZnO nanowire-based sensor exhibited the high surface-to-volume ratio of 58.6 mu m(-1) and the significantly high sensitivity of about 10 even for the low ethanol concentration of 0.2 ppm.open115860sciescopu

Prevalence and awareness of lower urinary tract symptoms among males in the Outpatient Clinics of Universiti Kebangsaan Malaysia Medical Centre.

This study aims to determine the prevalence of lower urinary tract symptoms (LUTS) and level of awareness among male outpatients in Universiti Kebangsaan Malaysia Medical Centre (UKMMC). A questionnaire consisting of demographic data, questions related to knowledge, attitude and practice on BPH and the International Prostate Symptom Score (IPSS) was used for this study. Uroflowmetry and bladder scan were used to evaluate the function of the urinary tract and severity of BPH. Urine dipstick was done for glycosuria, proteinuria and haematuria. A total of 220 respondents were surveyed. The prevalence of moderately and severely symptomatic LUTS was 42.7%. The most commonly reported LUTS were nocturia (78.2%), frequency (58.2%) and incomplete emptying (44.6%). The prevalence of glycosuria, proteinuria and haematuria were 23.6%, 11.4% and 1.8% respectively. There was a significant association between increasing age with the severity of LUTS (p=0.005). Out of 102 respondents with voided urine volume greater than 150 mL, there was a significant decrease in maximum (Qmax) (p=0.039) and average (Qave) urine flow rates with every 10 years increase of age (p=0.001). The majority of respondents (59.5%) have heard of BPH before. Over 78.2% of the respondents would seek medical attention if they have LUTS with 15.9% saying they would seek traditional treatment. In conclusion, the prevalence of LUTS was high and the level of awareness was satisfactory

Wnt/β-catenin signaling pathway activation is required for proliferation of chicken primordial germ cells in vitro

Here, we investigated the role of the Wnt/β-catenin signaling pathway in chicken primordial germ cells (PGCs) in vitro. We confirmed the expression of Wnt signaling pathway-related genes and the localization of β-catenin in the nucleus, revealing that this pathway is potentially activated in chicken PGCs. Then, using the single-cell pick-up assay, we examined the proliferative capacity of cultured PGCs in response to Wnt ligands, a β-catenin-mediated Wnt signaling activator (6-bromoindirubin-3′-oxime [BIO]) or inhibitor (JW74), in the presence or absence of basic fibroblast growth factor (bFGF). WNT1, WNT3A, and BIO promoted the proliferation of chicken PGCs similarly to bFGF, whereas JW74 inhibited this proliferation. Meanwhile, such treatments in combination with bFGF did not show a synergistic effect. bFGF treatment could not rescue PGC proliferation in the presence of JW74. In addition, we confirmed the translocation of β-catenin into the nucleus by the addition of bFGF after JW74 treatment. These results indicate that there is signaling crosstalk between FGF and Wnt, and that β-catenin acts on PGC proliferation downstream of bFGF. In conclusion, our study suggests that Wnt signaling enhances the proliferation of chicken PGCs via the stabilization of β-catenin and activation of its downstream genes

Verilog Modeling of Transmission Line for USB 2.0 High-Speed PHY Interface

A Verilog model is proposed for transmission lines to perform the all-Verilog simulation of high-speed chip-to-chip interface system, which reduces the simulation time by around 770 times compared to the mixed-mode simulation. The single-pulse response of transmission line in SPICE model is converted into that in Verilog model by converting the full-scale analog signal into an 11-bit digital code after uniform time sampling. The receiver waveform of transmission line is calculated by adding or subtracting the single-pulse response in Verilog model depending on the transmitting digital code values with appropriate time delay. The application of this work to a USB 2.0 high-speed PHY interface reduces the simulation time to less than three minutes with error less than 5% while the mixed-mode simulation takes more than two days for the same circuit.X1133Ysciescopu

A Conceptual Framework for Designing Informatics-based Services in Manufacturing Industries

Numerous manufacturing companies have "servitized" their value propositions to address product commoditization and sustainability issues. Service-essentially different from a product-contributes to the fulfillment of customers&apos; unmet needs and increases the freedom of finding an environmentally more benign offering beyond simply offering the product. Informatics is a key to the design of services in manufacturing companies. Informatics facilitates the collection of various types of data from products and customers and enables the production and delivery of useful information for customers. This paper (1) proposes a conceptual framework for designing informatics-based services in manufacturing industries, (2) introduces a service design case study that the authors recently conducted with a major car manufacturer in Korea, and (3) suggests future research issues. This paper is expected to contribute to product-service integration in manufacturing companies in this information economy. (C) 2015 The Authors. Published by Elsevier B.Vopen1111Ysciescopu

Evaluation of 3D printed PCL/PLGA/beta-TCP versus collagen membranes for guided bone regeneration in a beagle implant model

Here, we compared 3D-printed polycaprolactone/poly(lactic-co-glycolic acid)/beta-tricalcium phosphate (PCL/PLGA/beta-TCP) membranes with the widely used collagen membranes for guided bone regeneration (GBR) in beagle implant models. For mechanical property comparison in dry and wet conditions and cytocompatibility determination, we analyzed the rate and pattern of cell proliferation of seeded fibroblasts and preosteoblasts using the cell counting kit-8 assay and scanning electron microscopy. Osteogenic differentiation was verified using alizarin red S staining. At 8 weeks following implantation in vivo using beagle dogs, computed tomography and histological analyses were performed after sacrifice. Cell proliferation rates in vitro indicated that early cell attachment was higher in collagen than in PCL/PLGA/beta-TCP membranes; however, the difference subsided by day 7. Similar outcomes were found for osteogenic differentiation, with approximately 2.5 times greater staining in collagen than PCL/PLGA/beta-TCP, but without significant difference by day 14. In vivo, bone regeneration in the defect area, represented by new bone formation and bone-to-implant contact, paralleled those associated with collagen membranes. However, tensile testing revealed that whereas the PCL/PLGA/beta-TCP membrane mechanical properties were conserved in both wet and dry states, the tensile property of collagen was reduced by 99% under wet conditions. Our results demonstrate in vitro and in vivo that PCL/PLGA/beta-TCP membranes have similar levels of biocompatibility and bone regeneration as collagen membranes. In particular, considering that GBR is always applied to a wet environment (e.g. blood, saliva), we demonstrated that PCL/PLGA/beta-TCP membranes maintained their form more reliably than collagen membranes in a wet setting, confirming their appropriateness as a GBR membrane.11109Ysciescopu

Protective Effect of Ginseng Polysaccharides on Influenza Viral Infection

Ginseng polysaccharide has been known to have multiple immunomodulatory effects. In this study, we investigated whether Panax ginseng polysaccharide (GP) would have a preventive effect on influenza infection. Administration of mice with GP prior to infection was found to confer a survival benefit against infection with H1N1 (A/PR/8/34) and H3N2 (A/Philippines/82) influenza viruses. Mice infected with the 2009 H1N1 virus suspended in GP solution showed moderately enhanced survival rates and lower levels of lung viral titers and the inflammatory cytokine (IL-6). Daily treatment of vaccinated mice with GP improved their survival against heterosubtypic lethal challenge. This study demonstrates the first evidence that GP can be used as a remedy against influenza viral infection