Scintillation properties of Tm-doped Lu3Al5O12 single crystals

Using the micro-pulling-down (μ-PD) method, Tm-doped Lu₃Al₅O₁₂ (Tm:LuAG) single crystals were grown to examine their scintillation properties. In transmittance spectra, they exhibited about 80% transparency in the wavelengths longer than 320 nm and five absorption lines due to Tm³⁺ 4f–4f transitions were observed. ²⁴¹Am α-ray excited radioluminescence spectra were measured and intense 4f–4f emission peaks were observed with the host emission. When excited by ¹³⁷Cs γ-Ray to obtain pulse height spectra, Tm 1% doped LuAG showed the highest light yield coupled with a photomultiplier (PMT) or a silicon avalanche photodiode (Si-APD). The light yield was estimated to be 5800 and 7300 photons/MeV for PMT and Si-APD, respectively. Decay time profiles consist of two exponential components and the fast and slow components are considered to be attributed to the host and the combination of the host and Tm³⁺ 4f–4f emission, respectively.     

Performance of SOR methods on modern vector and scalar processors

The building-cube method (BCM) is a new generation algorithm for CFD simulations. The basic idea of BCM is to simplify the algorithm in all stages of flow computation to achieve large-scale simulations. Calculation of a pressure field using the Successive Over Relaxation (SOR) method consumes most of the total execution time required for BCM. In this paper, effective implementations on modern vector and scalar processors are investigated. NEC SX-9 and Intel Nehalem-EX are the latest vector and scalar processors. Those processors have much higher peak performances than their previous-generation processors. However, their memory bandwidth improvement cannot catch up with the performance improvement of processors. This is the so-called memory wall problem. In our paper, we discuss optimization techniques for implementation of the SOR method based on architectural characteristics of these modern processors, and evaluate their effects on the sustained performances of these processors for BCM.     

MiR-10a in Pancreatic Juice as a Biomarker for Invasive Intraductal Papillary Mucinous Neoplasm by miRNA Sequencing

New biomarkers are needed to further stratify the risk of malignancy in intraductal papillary mucinous neoplasm (IPMN). Although microRNAs (miRNAs) are expected to be stable biomarkers, they can vary owing to a lack of definite internal controls. To identify universal biomarkers for invasive IPMN, we performed miRNA sequencing using tumor-normal paired samples. A total of 19 resected tissues and 13 pancreatic juice samples from 32 IPMN patients were analyzed for miRNA expression by next-generation sequencing with a two-step normalization of miRNA sequence data. The miRNAs involved in IPMN associated with invasive carcinoma were identified from this tissue analysis and further verified with the pancreatic juice samples. From the tumor-normal paired tissue analysis of the expression levels of 2792 miRNAs, 20 upregulated and 17 downregulated miRNAs were identified. In IPMN associated with invasive carcinoma (INV), miR-10a-5p and miR-221-3p were upregulated and miR-148a-3p was downregulated when compared with noninvasive IPMN. When these findings were further validated with pancreatic juice samples, miR-10a-5p was found to be elevated in INV (p = 0.002). Therefore, three differentially expressed miRNAs were identified in tissues with INV, and the expression of miR-10a-5p was also elevated in pancreatic juice samples with INV. MiR-10a-5p is a promising additional biomarker for invasive IPMN.     

Partially biobased polyamphiphile-bearing reactive epoxy groups in the side chains and its application to the hydrogel

Partially biobased polyamphiphile-bearing reactive epoxy groups in the side chains were obtained in 62–78 % yields by a radical copolymerization of limonene oxide (LO) and PEG methylacrylate (PEGA) with different feed ratios. Degree of LO incorporation into the copolymer was determined as 12–23 % by ¹H NMR spectroscopic analysis. The copolymer having LO unit:PEGA unit = 19:81 formed polymer associates in water, particle diameter of which was ranged mainly from 4 to 66 nm and hydrodynamic mean diameter was 12.3 nm. Its critical micelle concentration was determined as 0.53 g/L by fluorescence spectroscopic analysis. A cross-linking reaction of the epoxy groups in the side chains was conducted with 3.97 mol% (to the epoxy group) of branched poly(ethylene imine) as a cross-linker to give the corresponding hydrogel in 56 % yield. The hydrogel can absorb water as much as 13 times its own mass.     

Construction of a brain–machine hybrid system to evaluate adaptability of an insect

Insects perform adaptive behavior according to changing environmental conditions using comparatively small brains. Because adaptability is generated through the relationship among brain, body and environment, it is necessary to examine how a brain works under these conditions. In this study, to understand neural processing involved in adaptive behavior, we constructed a brain–machine hybrid system using motor signals related to the steering behavior of the male silkworm moth for controlling a two-wheeled mobile robot. We developed this hybrid system according to the following steps. (1) We selected steering signals corresponding to walking direction that were activated during neck swinging induced by optic flow and pheromone stimuli. (2) To control a robot by neural activity, we implemented a spike-behavior conversion rule such that frequency of the left and right neck motor neurons’ spikes was linearly converted into rotation of the wheels. (3) For electrophysiological multi-unit recordings on a robot, we developed small amplifiers. Using this hybrid system, we could observe the programmed behavioral pattern and orientation toward a pheromone source. Moreover, we compared the orientation behavior of moths and that of the hybrid system at different pheromone stimulus frequencies. From these experiments, we concluded that we could reconstruct silkworm moth behavior on the hybrid system.     

Observation of Multiple Gap Structures Using NdFeAsO<Subscript>1−<Emphasis Type="Italic">x</Emphasis></Subscript>F<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>–GaAs Tunneling Junction

We have carried out point contact tunneling measurements by contacting degenerated GaAs semiconductor to polycrystalline samples of NdFeAsO_1−x F _x with T _c=44−51±1.2. The obtained conductance curves have plural structures included in energy region of the superconducting gap. These structures are seen at almost the same bias positions on every measurement. And as temperature increases, the structures are smeared out. Thus, the structures are attributed to multiple gap structures. The gap values are Δ _S=6.3±0.3 meV, Δ _L=12.5±0.5 meV and 2Δ _S/k _B T _c=3.1±0.3, 2Δ _L/k _B T _c=6.2±0.7. Separately from these multiple gap structures, some fine structures are seen in outer energy region of the gap structures. We have calculated d² I/dV ² and T _c from using conventional s-wave Eliashberg equations by appropriately assuming α ² F(ω). The phonon positions of the calculated d² I/dV ² curve are in quite good agreement with that of experimental result. Moreover, the calculated T _c reproduces the experimental one.     

Equilibrium and kinetic studies of selective adsorption and separation for strontium using DtBuCH18C6 loaded resin

A crown ether loaded resin was prepared by successive impregnation and fixing the 4′,4′(5″)-di(tert-butylcyclohexano)-18-crown-6 (DtBuCH18C6) and its molecule modifier, 1-dodecanol, onto the porous silica/polymer composite support (SiO₂-P particles). The characterization of DtBuCH18C6 loaded resin was examined by thermal gravimetry and differential thermal analysis and electron probe microanalysis. The adsorption behavior of Sr(II), Cs(I), Ru(III), Pd(II), La(III), Nd(III), Sm(III), Gd(III), Zr(IV), and Mo(VI) was investigated by the batch method. Furthermore, the column test for Sr (II) was performed. The batch experiments were carried out by varying the shaking times, HNO₃ concentration, and initial concentration of metal ions. A relatively large K _d value above 182 cm³/g for Sr(II) was obtained in the presence of 3 M HNO₃. In contrast, the K _d values of Cs(I), Ru(III), Pd(II), La(III), Nd(III), Sm(III), Gd(III), Zr(IV), and Mo(VI) were considerably lower than 10 cm³/g. The adsorption of Sr(II) was found to be controlled by chemisorption mechanism, and followed a Langmuir-type adsorption equation. The breakthrough curve of Sr(II) had S-shaped profile, and the elution percentage was estimated to be 99.9% by using the eluent of H₂O.     

Potential of predominant activated sludge bacteria as recipients in conjugative plasmid transfer

We investigated the possibility of conjugative plasmid transfer to the predominant bacteria in activated sludge and the factors influencing the transfer frequency in the activated sludge process. We performed conjugative transfers of a self-transmissible, broad-host-range plasmid RP4 from Escherichia coli C600 to activated sludge bacteria by broth mating. Most of the activated sludge bacteria tested could acquire plasmid RP4, although the transfer frequencies varied from 8.8 x 10(-7) to 1.3 x 10(-2) transconjugants per recipient. The transfer frequencies in several strains were similar to, or higher than, that in intraspecific transfer to E. coli HB101. Matings under various environmental conditions showed that factors relevant to physiological activity, such as temperature and nutrient conditions, seemed to affect the transfer frequency. In addition, conjugative transfer was detected even in filtered raw and treated wastewaters. Thus, the predominant activated sludge bacteria seem to have sufficient potential as recipients in conjugative plasmid transfer under the conditions likely to occur in the activated sludge process. Transfer frequency was reduced by agitation in the presence of suspended solid. This may suggest that conjugative plasmid transfer is physically inhibited in aeration tanks.     

Microporous activated carbons from used coffee grounds for application to electric double‐layer capacitors

Electrochemical double‐layer capacitors (EDLCs) are devices that store enormous amounts of charge electrostatically when a potential is applied between electrodes of very high surface area (typically made of porous carbon) and an electrolyte. Wider commercialization of this technology has been held back by the lack of ultralow‐cost electrode materials. We demonstrate that used coffee grounds can be processed to form low‐cost electrodes. The surface and electrochemical characteristics of microporous activated carbons from used coffee grounds (CGCs) were measured. First, optimal times and temperatures for carbonization and activation were identified on the basis of Brunauer–Emmett–Teller (BET) surface area, pore volume, and pore size distribution. Second, CGCs were used as polarized electrodes in EDLCs, whose capacitances were evaluated using cyclic voltammetry. The results show that carbonization for 1 h at 600 °C with a heating rate of 300 °C/h, followed by CO₂ activation for 2 h at 1000 °C, affords the highest BET surface area (1867 m²/g) compared to other works. The produced CGCs have many micropores of less than 2 nm across, which contribute to the formation of an electric double layer. Capacitors made using these CGCs show the highest capacitance (103 F/g) in 0.8 M (C₂H₅)₄NBF₄/PC as an organic electrolyte, which is much higher than the ∼80 F/g typically used in organic‐electrolyte‐based commercial EDLCs, suggesting that coffee grounds are a useful electrode material. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Development of confocal laser microscope system for examination of microscopic characteristics of radiophotoluminescence glass dosemeters

A confocal laser microscope system was developed for the measurement of radiophotoluminescence (RPL) photons emitted from a minute alpha-ray-irradiated area in an RPL glass dosemeter. The system was composed mainly of an inverted-type microscope, an ultraviolet laser, an XY movable stage and photon-counting circuits. The photon-counting circuits were effective in the reduction of the background noise level in the measurement of RPL photons. The performance of this microscope system was examined by the observation of standard RPL glass samples irradiated using (241)Am alpha rays. The spatial resolution of this system was ～ 3 μm, and with regard to the sensitivity of this system, a hit of more than four to five alpha rays in unit area produced enough amount of RPL photons to construct the image.