Fabrication of Modified Random Phase Masks with Phase Modulation Elements Exhibiting Gaussian Profiles Using Molecular Migration under Photopolymerization

Random phase masks are important technical elements for realizing holographic memory systems that enable high density recording. However, the broadly distributed Fourier spectrum often presents a problem because wide recording spots result in reduced total storage capacity for a recording medium. In the present study, we propose modified random phase masks with phase modulation elements exhibiting Gaussian profiles to suppress the spread of the recording spot and keep it in a narrow area, based on the reduction of the high-frequency components in a random phase pattern. We confirm the effectiveness of the proposed random phase mask using simulations of a computer-generated binary hologram. However, issues still remain in terms of the fabrication of random phase masks with Gaussian profiles. Therefore, we evaluate the feasibility of fabricating the proposed random phase mask using molecular diffusion under photopolymerization. The results confirm the feasibility of this approach over a relatively wide area for actual fabrication

Chronic irradiation with low-dose-rate ¹³⁷Cs-γ rays inhibits NGF-induced neurite extension of PC12 cells via Ca²⁺/calmodulin-dependent kinase II activation

Chronic irradiation with low-dose-rate ¹³⁷Cs-γ rays inhibits the differentiation of human neural progenitor cells and influences the expression of proteins associated with several cellular functions. We aimed to determine whether such chronic irradiation influences the expression of proteins associated with PC12 cells. Chronic irradiation at 0.027 mGy/min resulted in inhibition of NGF-induced neurite extension. Furthermore, irradiation enhanced the nerve growth factor (NGF)-induced increase in the phosphorylation of extracellular signal–regulated kinase (ERK), but did not affect the phosphorylation of NGF receptors, suggesting that irradiation influences pathways unassociated with the activation of ERK. We then examined whether irradiation influenced the Akt−Rac1 pathway, which is unaffected by ERK activation. Chronic irradiation also enhanced the NGF-induced increase in Akt phosphorylation, but markedly inhibited the NGF-induced increase in Rac1 activity that is associated with neurite extension. These results suggest that the inhibitory effect of irradiation on neurite extension influences pathways unassociated with Akt activation. As Ca²⁺ /calmodulin-dependent kinase II (CaMKII) is known to inhibit the NGF-induced neurite extension in PC12 cells, independent of ERK and Akt activation, we next examined the effects of irradiation on CaMKII activation. Chronic irradiation induced CaMKII activation, while application of KN-62 (a specific inhibitor of CaMKII), attenuated increases in CaMKII activation and recovered neurite extension and NGF-induced increases in Rac1 activity that was inhibited by irradiation. Our results suggest that chronic irradiation with low-dose-rate γ-rays inhibits Rac1 activity via CaMKII activation, thereby inhibiting NGF-induced neurite extension

地方公共サービスにおける資源配分の効率性 : 生産と配分の2つの視点による実証分析

関西学院大

地方公共サービスにおける資源配分の効率性 : 生産と配分の２つの視点による実証分析

関西学院大

Adaptation by stochastic switching of a monostable genetic circuit in Escherichia coli

Stochastic switching of a bistable genetic circuit represents a potential cost-saving strategy for adaptation to environmental challenges. This study reports that stochastic switching of a monostable circuit can be sufficient to mediate reversible adaptation in E. coli

Application of Scanning-Imaging X-Ray Microscopy to Fluid Inclusion Candidates in Carbonates of Carbonaceous Chondrites

In order to search for such fluid inclusions in carbonaceous chondrites, a nondestructive technique using x-ray micro-absorption tomography combined with FIB sampling was developed and applied to a carbonaceous chondrite. They found fluid inclusion candidates in calcite grains, which were formed by aqueous alteration. However, they could not determine whether they are really aqueous fluids or merely voids. Phase and absorption contrast images can be simultaneously obtained in 3D by using scanning-imaging x-ray microscopy (SIXM). In refractive index, n=1-sigma+i(beta), in the real part, 1-sigma is the refractive index with decrement, sigma, which is nearly proportional to the density, and the imaginary part, beta, is the extinction coefficient, which is related to the liner attenuation coefficient, mu. Many phases, including water and organic materials as well as minerals, can be identified by SIXM, and this technique has potential availability for Hayabusa-2 sample analysis too. In this study, we examined quantitative performance of d and m values and the spatial resolution in SIXM by using standard materials, and applied this technique to carbonaceous chondrite samples. We used POM ([CH2O]n), silicon, quartz, forsterite, corundum, magnetite and nickel as standard materials for examining the sigma and mu values. A fluid inclusion in terrestrial quartz and bi-valve shell (Atrina vexillum), which are composed of calcite and organic layers with different thickness, were also used for examining the spatial resolution. The Ivuna (CI) and Sutter's Mill (CM) meteorites were used as carbonaceous chondrite samples. Rod- or cube-shaped samples 20-30 micron in size were extracted by using FIB from cross-sectional surfaces of the standard materials or polished thin sections of the chondrites, which was previously observed with SEM. Then, the sample was attached to a thin W-needle and imaged by SIXM system at beamline BL47XU, SPring-8, Japan. The slice thickness was 109.3 nm and the pixel size was mostly 100 nm