Poly(ethylene‐2,6‐naphthalate) nanofiber prepared by carbon dioxide laser supersonic drawing

Poly(ethylene‐2,6‐naphthalate) (PEN) nanofiber was prepared by a carbon dioxide (CO₂) laser supersonic drawing. The CO₂ laser supersonic drawing was carried out by irradiating the laser to the as‐spun PEN fiber in a low‐temperature supersonic jet. The supersonic jet was generated by blowing off air into a vacuum chamber from a fiber supplying orifice. The flow velocity from the orifice can be estimated by applying Graham's theorem from the pressure difference between the atmospheric pressure and the pressure of the vacuum chamber. The fastest flow velocity estimated was 396 m s^?1 (Mach 1.15) at a chamber pressure of 6 KPa. The nanofiber obtained at Mach 1.15 was the oriented nanofibers with an average diameter of 0.259 μm, and its draw ratio estimated from the diameters before and after the drawing reached 430,822 times. The CO₂ laser supersonic drawing is a new method to make nanofiber without using any solvent or removing the second component. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Processing and formulation of drug nanoparticles by ternary cogrinding with methacrylic copolymer and sucrose fatty acid esters

Drug nanoparticles were prepared by cogrinding three components: a drug, a methacrylic copolymer, and sucrose fatty acid ester (SE). A high nanoparticle yield was obtained when cholesterol-lowering probucol (PBC), a poorly water–soluble drug, was used in the cogrinding process with D-1811, an SE with stearic acid as the fatty acid and the hydrophile–lipophile balance (HLB): 11. Investigation of the influence of HLB on SEs constituted with stearates revealed that the nanoparticle yield increased with increasing HLB of the SE; a particle-size distribution of about 100 nm (thought to originate from the drug) was observed. The PBC crystallinity was analyzed by powder X-ray diffraction and Raman spectroscopy before and after grinding. Its crystalline form changed from form I to form II with partial generation of the amorphous state. Granules with improved drug solubility and controlled-release performance were prepared by coating the particles with an aqueous suspension of the coground product. Observation of the coated granule surfaces by SEM and polarization microscopy revealed about a 10-μm-thick coating layer. In a dissolution test, controlled drug-release characteristics were observed under intestinal solubility conditions. Based on these results, functional pharmaceutical granules with enteric and sustained drug release were prepared.     

Thermal Conductivity Measurements of Some Synthetic Al2O3-CaO-SiO2 Slags by Means of a Front-Heating and Front-Detection Laser-Flash Method

The thermal conductivities of some synthetic slags containing Al₂O₃, CaO, and SiO₂ have been determined in the temperature range between 1623?K (1350?°C) and 1823?K (1550?°C) by applying a front-heating front-detection laser-flash method. In this method, the temperature response curve is measured in the short initial time period immediately after irradiating a laser pulse. The resultant values obtained by this method are unaffected by the radiative heat transfer. The temperature dependence of the thermal conductivity values were found not to be significant for all slag samples currently investigated. The thermal conductivity (??) of samples is represented with standard deviation less than 2?pct of its value as a function of compositions as follows: $$ \lambda = - 0.48\left[ {{\text{Al}}_{ 2} {\text{O}}_{ 3} } \right] - 0.57\left[ {\text{CaO}} \right] - 0.55\left[ {{\text{SiO}}_{2} } \right] + 57.1{\text{ W m}}^{ - 1} {\text{ K}}^{ - 1} $$ where [Al₂O₃], [CaO], and [SiO₂] are molar percent of Al₂O₃, CaO and SiO₂, respectively. The equation is suggested to cover the region of the following compositions: 8.0?mol pct < Al₂O₃ <21.0?mol pct, 31.5?mol pct < CaO <41.5?mol pct and 43.0?mol pct < SiO₂ <58.1?mol pct. The addition of Al₂O₃ to slags with a constant CaO/SiO₂ molar ratio resulted in an increase in thermal conductivity. In contrast, the effects of addition of SiO₂ and CaO are found to be insignificant.     

Microbiological safety of bottled mineral water in patients susceptible to infections

We evaluated the microbiological safety of bottled mineral water products commercially available in Japan. Of 10 bottled mineral water products manufactured in Japan, no bacteria or fungi were detected in 9 (90%), but 1 (10%) contained 1.8x10(3) colony-forming units (cfu)/mL. Of 12 bottled mineral water products manufactured in the EU, 11 (91.7%) contained 23-3.5x10(4) cfu/mL. On the other hand, of 5 bottled mineral water products manufactured in North America, 2 (40%) contained 2.3x10(2)-2.5x10(3) cfu/mL. The detected microorganisms were glucose-nonfermentative Gram-negative bacilli such as Brevundimonas vesicularis, Moraxella spp., and Burkholderia cepacia, but Pseudomonas aeruginosa was not detected in any product. For immunocompromised host patients being managed in ultra-clean rooms, the examined bottled mineral water products manufactured in Japan, except 1, were microbiologically safe.     

Crack-morphological aspects in fracture mechanics

Fracture mechanics can be regarded as a methodology to characterize the actual crack by using the parameters given by the analysis of a simple mathematical crack model. Therefore, the selection of these crack models has very significant meanings. In recent years, several precise crack models have been proposed.In this paper, we paid attention to the influences of the two-dimensional crack geometry and presented the numerical value of the elastic analytical solutions for the non-linear shaped cracks, those are, the bent, the curved and the branched crack. On the basis of these results, the characteristics of these cracks were discussed and the methods of approximate replacement to a simple straight crack were proposed.We examined a zig-zag growth of crack and the crack branching observed in actual fracture processes.     

Biomimetic phospholipid polymers for suppressing adsorption of saliva proteins on dental hydroxyapatite substrate

To prevent infectious diseases induced by the adhesion of microorganisms and their metabolic products to dental implants, saliva protein adsorption, which induces the plaque deposition to the intraoral substrates should be inhibited. We used a water-soluble 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer to modify the surface of hydroxyapatite (HAp) substrate, the main component of dental implant surface. The MPC polymer containing a catechol group at the terminal of polymer chain and amino groups in the side chain was synthesized by mimicking the mussel adhesive protein. The MPC polymer containing 2% of the primary amino groups showed effective adhesion to the HAp substrate. Mucin, the dental plaque protein, adsorbs on the HAp surface; however, the MPC polymer modification could reduce this adsorption amount by more than 98% compared to the original HAp substrate surface. Thus, the treatment of the MPC polymer has potential to reduce oral infection due to plaque deposition.     

Influence of 3‐D cross‐talk on qualified viewing spaces in two‐ and multi‐view autostereoscopic displays

Abstract— To estimate the qualified viewing spaces for two‐ and multi‐view autostereoscopic displays, the relationship between image quality (image comfort, annoying ghost image, depth perception) and various pairings between 3‐D cross‐talk in the left and right views are studied subjectively using a two‐view autostereoscopic display and test charts for the left and right views with ghost images due to artificial 3‐D cross‐talk. The artificial 3‐D cross‐talk was tuned to simulate the view in the intermediate zone of the viewing spaces. It was shown that the stereoscopic images on a two‐view autostereoscopic display cause discomfort when they are observed by the eye in the intermediate zone between the viewing spaces. This is because the ghost image due to large 3‐D cross‐talk in the intermediate zone elicits different depth perception from the depth induced by the original images for the left and right views, so the observer's depth perception is confused. Image comfort is also shown to be better for multi‐views, especially the width of the viewing space, which is narrower than the interpupillary distance, where the parallax of the cross‐talking image is small.     

Short-marks recording characteristics of laser-pumped magnetic-field-modulation recording in a narrow track pitch and on magnetically induced superresolution disks

We evaluate laser-pumped magnetic-field-modulation (LP-MFM), continuous laser-irradiated magnetic-field-modulation, andlight-intensity-modulation recording in magneto-optical disks, usingtemperature calculations and experiments. LP-MFM is useful forrecording short marks: One can record magnetic domains as small as 0.15-mum marks with LP-MFM by using a spin-polarized scanningelectron microscope. LP-MFM is also useful for reducing the trackpitch. Experiments showed that no cross write occurred at a 0.6-mum track pitch, and calculation showed that the heatdistribution is narrow. We confirmed the advantages of LP-MFM forrecording magnetically induced superresolution disks by investigatingthe difference in the shapes of the recorded domains.