Direct visualization of hetero-enzyme co-encapsulated in mesoporous silicas

In this study, a direct visualization technique was applied to the determination of a hetero-enzyme co-encapsulated in pores of mesoporous silicas in solution. Lipase and trypsin modified with fluorescent dyes, used as model enzymes, were co-encapsulated at the same instant in two kinds of mesoporous silicas – FSM-22 and SBA-15 – with pore diameters of 4.2 and 7.1 nm, respectively. A direct observation of composite materials of a hetero-enzyme and a mesoporous silica by a combination of differential interference contrast and fluorescence microscopy revealed that the enzymes were uniformly dispersed throughout the particles of the mesoporous silicas, because of the successful incorporation of the two enzymes. Moreover, lipase and trypsin co-encapsulated in the mesopores maintained their enzymatic activities in hydrolysis reactions of their substrates (triglyceride and casein, respectively), without loss of their enzymatic activities due to structural degradation.     

Relation between microstructure,properties and spark plasma sintering (SPS) parameters of pure ultrafine WC powder

A combined experimental/numerical methodology is developed to fully consolidate pure ultrafine WC powder under a current-control mode. Three applied currents, 1900, 2100 and 2700 A, and a constant pressure of 20 MPa were employed as process conditions. The developed spark plasma sintering (SPS) finite-element model includes a moving-mesh technique to account for the contact resistance change due to sintering shrinkage and punch sliding. The effects of the heating rate on the microstructure and hardness were investigated in detail along the sample radius from both experimental and modeling points of view. The maximum hardness (2700 HV10) was achieved for a current of 1900 A at the core sample, while the maximum densification was achieved for 2100 and 2700 A. A direct relationship between the compact microstructure and both the sintering temperature and the heating rate was established.     

Effects of Channel Width on Stress Enhancement for Damascene-Gate nFETs With Top-Cut Tensile-Stress Liner

This letter provides channel-stress behavior results induced by a local strain technique which consists of the process combination of a damascene-gate and top-cut tensile stress SiN liner for narrow channel-width nFETs using 3-D stress simulations and demonstrations. The dummy-gate removal, which is an intrinsic step in the damascene-gate process, is found to enhance tensile channel stress along the gate length at the edge of the channel beside the shallow trench isolation. In consequence of a mobility boost due to the high tensile stress, drain-current enhancement in the saturation is achieved for the damascene-gate nFETs with the narrow channel width and short gate length.     

A VHF interferometry system for detecting anomalous propagation of FM radio broadcasting waves related to earthquakes and some preliminary results

Earthquake‐related anomalous electromagnetic phenomena have been reported in various frequency ranges over the past few decades. Investigation of the anomalous propagation of VHF transmitter waves is a promising approach to short‐term prediction and crustal activity monitoring. Anomalous propagation is believed to be generated by disturbances of the atmosphere above the epicenter or along the propagation path prior to large earthquakes. Consequently, over‐the‐horizon propagation has been received. A recent study shows that the appearance of anomalies was signi?cantly enhanced within 5 days of earthquakes with M ≥4.8. However, there is no information on the scattering location, that is, on the direction of wave arrival. Therefore, a simple interferometer system for VHF radio waves to identify the space‐time position of earthquake‐related atmospheric disturbances has been developed and installed at Chiba University. This paper describes the newly developed interferometer system and presents the results of fundamental tests to evaluate the performance of the new interferometer at Chiba. Data on over‐the‐horizon propagation of VHF radio waves obtained from 1‐year continuous measurement at Chiba are described. These are possible radio duct propagations and possible earthquake‐related anomalous propagations. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 183(1): 16–24, 2013; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22303     

Regional difference of water content in human skin studied by diffuse-reflectance near-infrared spectroscopy: consideration of measurement depth

Diffuse reflectance (DF) spectra in the 1250-2500 nm region were measured in vivo for the skin of the forehead, cheek, jaw, elbow, volar forearm, palm, knee, and heel of seven healthy volunteers, using a Fourier transform near-infrared (FT-NIR) spectrophotometer with a fiber-optic probe. Apparent regional differences of water content in the skin, as estimated from the diffuse reflectance NIR spectra, are discussed in relation to the influence of measurement depth. The NIR spectra were collected with or without a 300 microm gap between the fiber-optic probe and the skin surface. For comparison, in vitro NIR spectra of stratum corneum sheets equilibrated at 41, 50, 63, and 81% relative humidity, at 25 degrees C, were also obtained. There was a difference in the ratio of the two water bands centered near 1450 nm and 1900 nm between the contact and non-contact measurements. In addition, regional differences of water content calculated from the peak height of the 1900 nm water band, which was normalized to the peak height of the 2175 nm amide band, were compared. The results of Monte Carlo simulation indicated that the apparent regional differences arise at least in part from differences in the measurement depth due to differences in specular reflection at the skin surface and in the thickness of the stratum corneum.     

Synthesis and characterization of polystyrene brushes for organic thin film transistors

We synthesized and characterized polystyrene brushes on a silicon wafer using surface-initiated atom transfer radical polymerization. The thickness of the polymer brush was controlled by adjusting the reaction time. We investigated monomer conversion as well as the molecular weight and density of the polymer brushes. When the monomer conversion reached 100%, the number-average molecular weight and film thickness reached 135,000 and 113 nm, respectively. The estimated densities of the synthesized polystyrene brushes were in the range 0.34-0.54 chains/nm2, high enough to be categorized in the "concentrated brush" regime. The synthesized polymer brush was used as an insulating layer in an organic thin-film transistor. Organic thin-film transistors were fabricated using pentacene as an active p-type organic semiconductor and a polystyrene brush on a SiO2 layer as a gate dielectric. The pentacene based organic thin-film transistor with the polystyrene brush exhibited a field-effect mobility microFET of 0.099 cm2/(V x s).     

In-flight thermal treatment of soda-lime-silica glass powders for glass production by argon–oxygen induction thermal plasmas

In order to investigate the plasma–particle energy exchange dynamics and optimize the plasma discharge and particle parameters during in-flight thermal treatment of soda-lime-silica glass powders, a plasma–particle interaction model was developed. This model solved the conservation equations to predict the plasma temperature and flow fields, and then calculated the injected individual particle trajectories and temperature histories, and the particle source terms to take into account the plasma–particle interaction. It was noticed that particle injection significantly reduced the plasma temperature around the centerline of the torch and hence decreased the heat transfer to particles at higher carrier gas flow-rate and powder feed-rate. As a result the size and composition of quenched particles were affected significantly by the above factors. The simulated results were consistent with those of experiment, which provided valuable guidelines in optimizing the plasma discharge and particle parameters for the efficient thermal treatment of soda-lime-silica glass particles.