Elastic modulus and in vitro biocompatibility of Ti−xNb and Ti−xTa alloys

The effect of niobium and tantalum on the elastic modulus and the in vitro biocompatibility in binary titanium alloys was studied. The Young's modulus of titanium was effectively lowered with additions of Nb or Ta, depending significantly upon the microstructure. Martensitic microstructures such as α' and α" decreased the elastic modulus, while the ω phase increased it. Ti−10%Nb, Ti−30%Nb and Ti−30%Ta alloys exhibited very low elastic moduli of 74, 80, and 58 GPa, respectively. The corrosion resistance of Ti−xTa was slightly higher than that of Ti−xNb, which was comparable to that of CP Ti or Ti−6A−4V. No ion release was detected in Hank's solution, while Ti ions were released in 0.1% lactic acid ranging from 0.03 to 0.11 μg/ml for both the Ti−xNb and Ti−xTa alloys. MG63 osteoblast-like cell proliferation on Ti−30%Ta was less active compared with Ti−30%Nb, CP Ti or Ti−6Al−4V.     

In vitro studies of bioglass material by X-ray diffraction and solid-state MAS-NMR

Bioactive glass 46S6 has been elaborated by melting method at high temperature. “In vitro” experiments of 46S6 glass were carried out by soaking in a simulated body fluid for different times. The kinetics of chemical reactivity and the bioactivity of this biomaterial was investigated by X-ray diffraction and elucidated by using an original structural analysis method based on solid-state MAS-NMR. After in vitro assays, X-ray diffraction confirmed the high bioactivity of bioglass 46S6. The ²⁹Si MAS-NMR spectra showed the emergence of two new species: Q _Si ³ (OH) Q _Si ⁴ and which are characteristic of the dissolution of vitreous network of 46S6 glass while the ³¹P MAS-NMR spectra highlighted the formation of new component attributed to hydroxycarbonate apatite. The bioglass 46S6 have presented the rapid formation of a biological active hydroxycarbonate apatite layer after soaking in simulated body fluid fluid.     

Experimental investigation of current distribution in a direct methanol fuel cell with serpentine flow-fields under various operating conditions

The influences of various operating conditions on the current distribution of a direct methanol fuel cell with flow-fields of serpentine channels are investigated by means of a current-mapping method. The current densities generally deviate more from an even distribution when the cell temperature or flow rate of the cathode reactant is lower, or when the current loaded on the cell or the methanol concentration is higher. In addition, uneven current distributions decrease the cell performance. Relevant mass-transfer phenomena such as water flooding and methanol crossover are discussed. The characteristics of the channel configuration also affect the current density profiles. With a five-line serpentine channel, the current densities are lowered periodically where the flow direction is inverted due to the corner flow effect and the subsequent water accumulation. With a single serpentine channel, on the other hand, the current densities peak periodically where the flow direction is inverted due to enhanced air convection through the gas-diffusion layer.     

Measurement of the Electron Bernstein Wave Emission with One of the Power Transmission Lines for ECH in LHD

Possibility of the measurement of radiated waves derived from the thermally emitted electron Bernstein wave （EBW） is numerically investigated based on the assum...     

Ionic‐Liquid‐Assisted Sonochemical Synthesis of Carbon‐Nanotube‐Based Nanohybrids: Control in the Structures and Interfacial Characteristics

A versatile, facile, and rapid synthetic method of advanced carbon nanotube (CNT)‐based nanohybrid fabrication, or the so‐called ionic‐liquid‐assisted sonochemical method (ILASM), which combines the supramolecular chemistry between ionic liquids (ILs) and CNTs with sonochemistry for the control in the size and amount of uniformly decorated nanoparticles (NPs) and interfacial engineering, is reported. The excellence in electrocatalysis of hybrid materials with well‐designed nanostructures and favorable interfaces is demonstrated by applying them to electrochemical catalysis. The synthetic method discussed in this report has an important and immediate impact not only on the design and synthesis of functional hybrid nanomaterials by supramolecular chemistry and sonochemistry but also on applications of the same into electrochemical devices such as sensors, fuel cells, solar cells, actuators, batteries, and capacitors.     

Object‐order template‐based approach for stereoscopic volume rendering

Stereoscopic volume rendering provides powerful depth information, but it takes a long time to render two‐eye images. Previous algorithms based on reprojection methods project the result of one view of a stereo pair into the other instead of rendering a new one completely. Because of inaccurate mapping between the two images, the quality of the reprojected image is not satisfactory. This paper presents a new algorithm to preserve the accuracy of both images with very little increase in computation time. The efficiency of the new algorithm comes from the use of ray templates and object‐order processing. This algorithm makes two different templates for each eye and renders two images simultaneously, tracing the volume only once in object order. We also extend the algorithm to support image‐space supersampling by using more ray templates. Experimental results show that the image quality of the new algorithm is not only comparable with that of ray casting but also the rendering speed is near that of the interactive shear–warp algorithm employing object‐order processing and spatial data coherency. Copyright © 1999 John Wiley & Sons, Ltd.     

Umbilical polyp originating from urachal remnants

Umbilical polyp is a rare disorder of the umbilical region in childhood. It is said to be the result of incomplete closure of the omphalomesenteric duct and presents as a red, moist umbilical mass after separation of the umbilical cord. Umbilical polyp originating from the urachus has not previously been reported. A 10-year-old boy with an umbilical polyp related to the urachus is presented to stress the possibility that umbilical polyps can originate not only from the omphalomesenteric duct but also from urachal remnants.