Molecular structure and developmental expression of zebrafish atp2a genes

[[abstract]]We isolated two atp2a genes, atp2a1 and atp2a2a, from embryonic zebrafish. Amino acid sequences deduced from zebrafish atp2a genes are aligned with orthologue proteins from other species, the results showed that they share high percentage of identities (82%–94%) and acidic pIs (5.03–5.33). Whole mount in situ hybridization experiments showed that atp2a1 and atp2a2a are maternal inherited genes which can be detected at 1-cell stage embryos and express in the entire animal pole from 6 hours post-fertilization (hpf) to 12 hpf. At the later stages (48–96 hpf), expression of atp2a1 was restricted in head and trunk muscles as well as in some neurons. In contrast to the strongly expression of atp2a1 in head muscle, expression of atp2a2a was detected in head muscle in a fainter manner. In addition, transcripts of atp2a2a were observed in the developing heart during early cardiogenesis. The present studies not only help us to comparatively analyze atp2a genes across species, but also provide useful information about expressions during early embryogenesis that will help in further investigations of functional studies of Atp2a in the future.[[incitationindex]]SCI[[booktype]]紙

Nonlinear dependence between the surface reflectance and the duty-cycle of semiconductor nanorod array

The nonlinear dependence between the duty-cycle of semiconductor nanorod array and its surface reflectance minimization is demonstrated. The duty-cycle control on thin-SiO(2) covered Si nanorod array is performed by O(2-) plasma pre-etching the self-assembled polystyrene nanosphere array mask with area density of 4 x 10(8) rod/cm(-2). The 120-nm high SiO(2) covered Si nanorod array is obtained after subsequent CF(4)/O(2) plasma etching for 160 sec. This results in a tunable nanorod diameter from 445 to 285 nm after etching from 30 to 80 sec, corresponding to a varying nanorod duty-cycle from 89% to 57%. The TM-mode reflection analysis shows a diminishing Brewster angle shifted from 71 degrees to 54 degrees with increasing nanorod duty-cycle from 57% to 89% at 532 nm. The greatly reduced small-angle reflectance reveals a nonlinear trend with enlarging duty-cycle, leading to a minimum surface reflectance at nanorod duty-cycle of 85%. Both the simulation and experiment indicate that such a surface reflectance minimum is even lower than that of a uniformly SiO(2) covered Si substrate on account of its periodical nanorod array architecture with tuned duty-cycle. (C) 2011 Optical Society of Americ

Preparation and optical properties of Ta2O5-x thin films

Thin films of tantalum pentoxide (Ta2O5-x) were deposited on glass substrates by RF magnetron sputtering under different Ar/O-2 flow ratios. Characterization of the coatings was investigated by UV-vis spectroscopy, ellipsometry (at a wavelength of 632.8 nm), Fourier transform infrared (FTIR) spectroscopy, atomic force microscope (AFM), and transmission electron microscope energy dispersive spectrometer (TEMEDS). It was obtained that the Ta2O5-x films produced with different Ar/O-2 ratios ranging from 10/6 to 8/10 exhibit good visible optical transmissions, 80-90%. The optical band gap of the films from 10/6 to 8/10 decreased from 4.25 to 3.70 eV from the transmission spectra. The film thickness decreased from 108.1 to 99.4 nm and refractive index increased from 2.02 to 2.15 for the films produced with different Ar/O-2 ratios ranging from 10/6 to 8/10. In addition, the results indicate that the films prepared at high Ar/O-2 flow ratios (8/10) have featureless peak of suboxide for FTIR spectra and exhibit atomic ratio Ta:O = 1:2.41 for TEMEDS analysis. (C) 2007 Elsevier B.V. All rights reserved

Ultrahydrophobic and Microporous Electrodes Fabricated by Fluorocarbon Plasma Etching of Carbon Fiber

The ultrahydrophobic, conductive, and porous properties of microporous electrodes (MPEs) are successfully deposited by a reactive ion etcher with the CHF(3) plasma treatment. The electrodes fabricated with CHF(3) plasma exhibit a good water-repellent behavior due to hydrophobic groups such as -CF(2) and -CF(3) groups and the ultrahydrophobic properties are achieved when the water contact angle is greater than 130 degrees. The proton exchange membrane fuel cell performance, related to surface properties of Teflon-like MPEs, is studied by fuel cell system and X-ray photoelectron spectroscopy. The F/(C, H, S) ratio of fluorine-based precursor is the main parameter to adjust the conductivity, porosity, and ultrahydrophobicity of the electrodes. When the electrodes are fabricated with a F/(C, H, S) ratio of fluorine-based precursor of 1.5, it has a much more stable output density, with an optimal power output of 350 mW/cm(2) corresponding to a current density of 800 mA/cm(2), than that fabricated with a F/(C, H, S) ratio of fluorine-based precursor of 4 during the long-duration test

Teflon-Coated Carbon Fiber Core/Shell Structure Based Hydrophobic Gas-Diffusion Electrode for Proton Exchange Membrane Fuel Cells

Teflon-like film-covered carbon fiber fabricated using the CHF(3) plasma technology as a core/shell-like structure for the hydrophobic porous gas diffusion electrode (GDE) formation is successfully demonstrated for use in proton exchange membrane fuel cells (PEMFCs). The Teflon-like film, with thicknesses up to 1200 nm, produces an optimum water contact angle (WCA) of 131 degrees, which is attributed to the superior cross-linking density and greater number of -CF(2) functional groups. When compared with the film grown on a planar Si substrate, a similar WCA tendency was clearly observed; nevertheless, all of the obvious value was reduced in Delta WCA/WCA=23% due to the Lotus effect. The PEMFC measurements show that GDE with a Teflon-like film thickness of 1200 nm modules has the best performance with a maximum power density of 0.52 W/cm(2). However, cell performance tends to decline when the film thickness is increased to 2700 nm, a result which is ascribed to the great sheet resistance and Teflon-like film cracks of the GDE

Enhancement of blue-green photoluminescence in B2O3 fritted ZrO2:Ce3+ phosphor

Blue-green emission of ZrO2:Ce3+ phosphor, prepared by solid-state reaction, is demonstrated. The phosphor presents a strong and broad photoluminescence band centered at 496 nm with excitation at 291 nm. The optimized Ce content is 2.5 mol% for the strongest emission of ZrO2:Ce3+ phosphors prepared without B2O3. The PL intensity is enhanced by at least 3 dB by adding 5.0 mol% B2O3 within the ZrO2:Ce3+ containing 5.0 mol% Ce during synthesis. Increase of the B2O3 flux effectively induces the Ce ions to substitute the Zr ions in ZrO2 lattice and causes the ZrO2 lattice distortion. The formation of Ce0.75Zr0.25O2 compound within the ZrO2:Ce3+ occurred when the Ce content is greater than or equal to 2.5 mol% for the phosphors prepared without B2O3 and leads to a degradation of the phosphor PL intensity due to the host effect. The addition of B2O3 during the preparation of phosphors containing Ce ions lower than or equal to 5.0 mol% essentially restrains the Ce0.75Zr0.25O2 formation and then enhances the blue-green PL. (C) 2009 Elsevier B.V. All rights reserve

Electron-beam reduction method for preparing electrocatalytic particles for membrane electrode assemblies (MEA)

A new method, the electron-beam (e-beam) reduction method, is presented for fuel cell electrocatalytic particle preparation. The method utilizes the idea of reducing ions of the catalyst species right on the carbon cloth fibers and the multi walled carbon nano tubes (MWNTs) via direct electron-beam bombardment. The morphology of the electron-beam reduced catalyst particles is presented to show that the catalyst particles were dispersed in an equal and homogeneous manner within the MWNTs/carbon cloth electrode carriers, and imply that the electroactive surface area of the e-beam reduced catalysts should assume a larger value than those from currently reported methods. With the Pt (catalyst) loadings being controlled, data obtained from electrochemical and polarization tests show that the electrodes and membrane electrode assemblies (MEA) prepared from the e-beam reduction have larger active surface areas and better working performances than those prepared from the sputtering method; the quantitative results show good consistency with the qualitative morphology images. (c) 2006 Elsevier B.V. All rights reserved

Effect of GePt buffer layer on magnetic properties and microstructure of FePt films

We have explored the interlayer diffusion effect of Ge/FePt, GePt/FePt bilayer on the formation of ordered L1(0) FePt phase. In Ge/FePt bilayer, the Ge3Pt2 compound was formed during post annealing at 400 degrees C for 1.0 h. Diffusion between Ge and FePt layer suppres the formation of ordered L1(0) FePt phase. With Ge2Pt3 underlayer, the FePt film was ordered at 400 degrees C and the in-plane coercivity was 9.3 kOe. The ordering temperature was reduced about 50 degrees C compared to the single layer FePt film. (C) 2006 Elsevier B. V. All rights reserved

Characterization of Teflon-like carbon cloth prepared by plasma surface modification for use as gas diffusion backing in membrane electrode assembly

The hydrophobic property of carbon was largely improved by plasma treatment and the Teflon-like property was effectively applied to fabricate a gas diffusion backing (GDB) for use in membrane electrode assembly (MEA). The surface morphology, hydrophilic/hydrophobic property and electron conductivity of the as-prepared GDB was fully characterized. The water contact angle and SEM microstructure image of the CF(4), CHF(3) plasma-treated GDB were both indicated as similar to 130 degrees, and very few gas diffusion pores either sealed or blocked by excessive hydrophobic material residual. The measured resistivity values of CF(4) plasma, CHF(3) plasma, SF(6) plasma and commercial carbon were 0.45, 0.5, 0.47 and 0.49, respectively, which indicates that the electrical resistivity of carbon cloth with CF(4) plasma treatment was slightly lower than others. In cell performance test, the CF(4) plasma-treated modules could also produce better property than those MEAs prepared with CHF(3) plasma-treated GDB, SF(6) plasma-treated GDB and commercially available GDB, leading to the highest fuel cell performance with an optimal power output of 350 mW cm(-2). (C) 2008 Elsevier B.V. All rights reserved