High-intensity laser-driven particle and electromagnetic wave sources for science, industry, and medicine

We simultaneously observed both the fast proton generation and terahertz (THz) radiation in the laser pulse interaction with a thin-foil target.The maximum proton energy of ～2.3 MeV and an intense THz radiation were observed at the pulse duration of ～30fs.We also measured the proton beam and UV harmonics from a thin-foil target by changing the laser pulse duration.In the case of the ～500 fs, peaks of UV harmonics up to fourth order appeared.This unique combination of the multiple beams will provide useful applications such as pump-probe experiments.     

Blue-shifted stimulated emission from ZnO films deposited on SiO2 by atomic layer deposition

ZnO films were prepared by atomic layer deposition upon a SiO₂ layer on a Si substrate and treated by rapid thermal annealing. The optically-pumped random lasing actions with low threshold values were observed in the ZnO films on SiO₂/Si substrates. With the decrease in ZnO film thickness or the increase in post-annealing duration, the stimulated emission shifted toward the shorter wavelength and the lasing threshold increased. The results can be attributed to the inter-diffusion between ZnO and SiO₂, which causes the modification of bandgap renormalization in ZnO.     

The High-Resolution X-Ray Microcalorimeter Spectrometer, SXS, on Astro-H

The science and an overview of the Soft X-ray Spectrometer onboard the STRO-H mission are presented. The SXS consists of X-ray focusing mirrors and a microcalorimeter array and is developed by international collaboration lead by JAXA and NASA with European participation. The detector is a 6×6 format microcalorimeter array operated at a cryogenic temperature of 50 mK and covers a 3′×3′ field of view of the X-ray telescope of 5.6 m focal length. We expect an energy resolution better than 7 eV (FWHM, requirement) with a goal of 4 eV. The effective area of the instrument will be 225 cm² at 7 keV; by a factor of about two larger than that of the X-ray microcalorimeter on board Suzaku. One of the main scientific objectives of the SXS is to investigate turbulent and/or macroscopic motions of hot gas in clusters of galaxies.     

Crystal growth and characterization of Tm doped mixed rare-earth aluminum perovskite

In this work, we present results of structural characterization and optical properties including radio luminescence of (Lu_xGd_yY_0.99?x?yTm_0.01)AP single crystal scintillators for (x, y) = (0.30, 0.19), (0, 0.19) and (0, 0) grown by the micro-pulling-down (μ-PD) method. The grown crystals were single phase materials with perovskite structure (Pbnm) as confirmed by XRD and had a good crystallinity. The distribution of the crystal constituents in growth direction was evaluated, and significant segregation of Lu and Gd was detected in (Lu_0.30Gd_0.19Y_0.50Tm_0.01)AP sample. The crystals demonstrated 70% transmittance in visible wavelength range and some absorption bands due to Tm³⁺, Gd³⁺ and color centers were exhibited in 190–900 nm. The radioluminescence measurement under X-ray irradiation demonstrated several emission peaks ascribed to 4f–4f transitions of Tm³⁺ and Gd³⁺. The ratio of emission intensity in longer wavelength range was increased when Y was replaced by Lu or Gd.     

Stability test for amorphous materials in humidity controlled 96-well plates by near-infrared spectroscopy

The purpose of this research is to apply near infrared spectrometry (NIR) with chemoinformetrics to predict the change of crystalline properties of indomethacin (IMC) amorphous under various levels of relative humidity storage conditions. Stability test for amorphous and meta-stable polymorphic forms was performed in humidity controlled the modified 96-well quartz plates containing various kinds of saturated salt solutions (0-100% of relative humidity (RH)) by NIR spectroscopy. Amorphous form was obtained melt product to pour into liquid nitrogen and after then ground. Samples were stored at 25°C in the 6-well plates at various levels of RH. The spectra of the powder samples were measured by the reflectance FT-NIR spectrometer. The second derivative spectra of form α showed specific absorption peaks at 4980, 6036, 7296 and 8616 cm-1 and that of form γ showed those at 5020, 5028, 7344, 7428 and 8436 cm-1. After storage at less than 50% RH, the peak intensities at 5020, 5028, 7344, 7428 and 8436 cm-1 of the amorphous solid increased with increasing of storage time. However, the peak intensity at 4980, 6036 and 7296 cm-1 increased at more than 50% RH Please check and confirm the edit. The results suggested that at lower humidity, the IMC amorphous solid transformed into form γ, but it transformed into form α at more than high humidity. It is possible that crystalline stability of the pharmaceutical preparations could be predicted by using humidity controlled 96-well plates and reflectance NIR-chemoinformetric methods.     

Effects of lubricant-mixing time on prolongation of dissolution time and its prediction by measuring near infrared spectra from tablets

The relationship between lubricant-mixing time and dissolution time was investigated, and we established a calibration model to predict dissolution time by near infrared (NIR) spectroscopy and the rationale of the prediction. The bulk powder consisted of theophylline, lactose, and potato starch were pre-mixed. After magnesium stearate (Mg-St) was added, the material was mixed for up to 180?min. The mixed powders were compressed to tablets and dissolution tests were performed. From each dissolution curve, 50% dissolution time (T50) was calculated. The NIR spectra of each tablet's upper surface was measured and a chemometric analysis was conducted. With the extension of mixing time, T50 was prolonged. The Mg-St widely covered the surface of each particle of the bulk powder after material mixing. This coating effect may decrease the wettability of the particles and cause the prolongation of dissolution time. The T50 was predicted by NIR spectroscopy with chemometrics and a calibration model was established. The regression vector showed typical peaks derived from -CH group of Mg-St, and it is suggested that those peaks, which were caused by the thin layer extension of Mg-St particles over the particle surfaces of other materials, contributed to the prediction of T50 prolongation. These studies show the usefulness of NIR measurements to control the effect of a lubricant in the process of raw powder material mixing.     

Preparation of a novel bimodal catalytic membrane reactor and its application to ammonia decomposition for COx-free hydrogen production

A novel bimodal catalytic membrane reactor (BCMR) consisting of a Ru/γ-Al₂O₃/α-Al₂O₃ bimodal catalytic support and a silica separation layer was proposed. The catalytic activity of the support was successfully improved due to enhanced Ru dispersion by the increased specific surface area for the γ-Al₂O₃/α-Al₂O₃ bimodal structure. The silica separation layer was prepared via a sol–gel process, showing a H₂ permeance of 2.6 × 10⁻⁷ mol Pa⁻¹ m⁻² s⁻¹, with H₂/NH₃ and H₂/N₂ permeance ratios of 120 and 180 at 500 °C. The BCMR was applied to NH₃ decomposition for CO_x-free hydrogen production. When the reaction was carried out with a NH₃ feed flow rate of 40 ml min⁻¹ at 450 °C and the reaction pressure was increased from 0.1 to 0.3 MPa, NH₃ conversion decreased from 50.8 to 35.5% without H₂ extraction mainly due to the increased H₂ inhibition effect. With H₂ extraction, however, NH₃ conversion increased from 68.8 to 74.4% due to the enhanced driving force for H₂ permeation through the membrane.     

Carbon nanotube-coated silicone as a flexible and electrically conductive biomedical material

Artificial cell scaffolds that support cell adhesion, growth, and organization need to be fabricated for various purposes. Recently, there have been increasing reports of cell patterning using electrical fields. We fabricated scaffolds consisting of silicone sheets coated with single-walled (SW) or multi-walled (MW) carbon nanotubes (CNTs) and evaluated their electrical properties and biocompatibility. We also performed cell alignment with dielectrophoresis using CNT-coated sheets as electrodes. Silicone coated with 10 μg/cm² SWCNTs exhibited the least sheet resistance (0.8 kΩ/sq); its conductivity was maintained even after 100 stretching cycles. CNT coating also improved cell adhesion and proliferation. When an electric field was applied to the cell suspension introduced on the CNT-coated scaffold, the cells became aligned in a pearl-chain pattern. These results indicate that CNT coating not only provides electro-conductivity but also promotes cell adhesion to the silicone scaffold; cells seeded on the scaffold can be organized using electricity. These findings demonstrate that CNT-coated silicone can be useful as a biocompatible scaffold.     

Preparation of low-crystalline apatite nanoparticles and their coating onto quartz substrates

We prepared low-crystalline apatite nanoparticles and coated them onto a surface of a Au/Cr-plated quartz substrate by the electrophoretic deposition (EPD) method or by using a self-assembled monolayer of 11-mercaptoundecanoic acid (SAM method). Low-crystalline apatite nanoparticles around 10?nm in size with extremely low contents of undesirable residual products were obtained by adding (NH(4))(2)HPO(4) aqueous droplets into a modified synthetic body fluid solution that contained Ca(CH(3)COO)(2). The apatite nanoparticles were successfully coated by either the EPD method or the SAM method; the nanoparticle coating achieved by the SAM method was more uniform than that achieved by the EPD method. The present SAM method is expected to be a promising technique for obtaining a quartz substrate coated with apatite nanoparticles, which can be used as a quartz crystal microbalance device.     

Preparation of core–shell poly(l-lactic) acid-nanocrystalline apatite hollow microspheres for bone repairing applications

In this paper, hybrid inorganic–organic core–shell hollow microspheres, made of poly(l-lactic acid) (PLLA) and biomimetic nano apatites (HA), were prepared from biodegradable and biocompatible substances, suitable for bone tissue applications. Preparation is started from Pickering emulsification, i.e., solid particle-stabilized emulsions in the absence of any molecular surfactant, where solid particles adsorbed to an oil–water interface. Stable oil-in-water emulsions were produced using biomimetic 20?nm sized HA nanocrystals as particulate emulsifier and a dichloromethane (CH₂Cl₂) solution of PLLA as oil phase. Hybrid hollow PLLA microspheres at three different HA nanocrystals surface coverage, ranging from 10 to 50?μm, were produced. The resulting materials were completely characterized with spectroscopic, calorimetric and microscopic techniques and the cytocompatibility was established by indirect contact tests with both fibroblasts and osteoblasts and direct contact with these latter. They displayed a high level of cytocompatibility and thus represent promising materials for drug delivery systems, cell carriers and scaffolds for regeneration of bone useful in the treatment of orthopaedic, maxillofacial and dental fields.