A study of reactor neutrino monitoring at the experimental fast reactor JOYO

We carried out a study of neutrino detection at the experimental fast reactor JOYO using a 0.76 tons gadolinium loaded liquid scintillator detector. The detector was set up on the ground level at 24.3 m from the JOYO reactor core of 140 MW thermal power. The measured neutrino event rate from reactor on-off comparison was 1.11±1.24(stat.)±0.46(syst.) events/day. Although the statistical significance of the measurement was not enough, backgrounds in such a compact detector at the ground level were studied in detail and MC simulations were found to describe the data well. A study for improvement of the detector for future such experiments is also shown.     

Characterization by Stm and Electrical Conductivity of Single-Walled Carbon Nanotubes

Abstract

Single-walled carbon nanotubes (SWCNT) prepared by a DC-Arc-Discharge and purified by a hydrothermal treatment followed by several steps of procedures including heating, burning, extracting and acid-washing are investigated by a conventional STM technique morphologically and spectroscopically. The electical resistivities of compacted pellets (mats) of SWCNT are measured as a function of temperature in the range from the room-temperature to 1.5K. The behaviors seems to be essentially originated in the metallic nature of individual SWCNT.     

Hydrothermal Synthesis and Formation Mechanisms of Lanthanum Tin Pyrochlore Oxide

Well-defined La₂Sn₂O₇ with a phase-pure pyrochlore structure was produced by hydrothermal synthesis at temperatures as low as 200°C. Production of phase-pure La₂Sn₂O₇ requires a pH above 10, and higher pH accelerates the crystallization process. The synthesis produced spherical particles of average particle size ∼0.59 μm (±0.12) and surface area ∼14.1 m²/g. SEM and TEM observation for morphologic evolution and kinetic analysis during crystallization indicated that La₂Sn₂O₇ formation probably proceeds via a two-step reaction. First a transient dissolution–precipitation occurs. Then the primary crystallites aggregate because of their colloidal instability, and heterocoagulation with the lanthanum hydrous oxide precursor particles also occurs. The sluggish reaction rate at the later stage of reaction is characterized by an in situ transformation, where the soluble tin species is diffused through the porous La₂Sn₂O₇ aggregates to react with entrapped lanthanum precursors.     

Separation of C6H6 and C6H12 from H2 using ionic liquid/PVDF composite membrane

Ionic liquid/polyvinylidene fluoride composite membrane was successfully prepared by impregnation method and used for the separation on organic chemical hydride process. The separation factors of C₆H₆/H₂ and C₆H₁₂/H₂ in the ternary mixture system were 7500 and 300, respectively. The ionic liquid membrane showed an excellent possibility as a technology of H₂ purification in the organic chemical hydride process by removing aromatic hydrocarbon and cycloalkane simultaneously from the ternary system. © 2015 American Institute of Chemical Engineers AIChE J, 62: 624–628, 2016     

Synthesis of thermoresponsive block and graft copolymers via the combination of living cationic polymerization and RAFT polymerization using a vinyl ether-type RAFT agent

A novel vinyl ether-type RAFT agent, benzyl 2-(vinyloxy)ethyl carbonotrithioate (BVCT) was synthesized for various block copolymers via the combination of living cationic polymerization of vinyl ethers and reversible addition−fragmentation chain transfer (RAFT) polymerization. The novel BVCT–trifluoroacetic acid adduct play an important role to produce well-defined block copolymers, which is both as a cationogen under EtAlCl₂ initiation system in the presence of ethyl acetate for living cationic polymerization and a RAFT agent for blocks by RAFT polymerization. The resulting polymer, poly(vinyl ether)s, by living cationic polymerization had a high number average α-end functionality (≥0.9) as determined by both ¹H NMR and MALDI-TOF-MS spectrometry. In addition, this poly(vinyl ether)s worked well as a macromolecular chain transfer agent for RAFT polymerization. The RAFT polymerization of radically polymerizable monomers was conducted in toluene using 2,2′-azobis(isobutyronitrile) at 70 °C. For example, a double thermoresponsive block copolymer (MOVE₆₁-b-NIPAM₁₅₀) consisting of 2-methoxyethyl vinyl ether (MOVE) and N-isopropylacrylamide (NIPAM) was prepared via the combination of living cationic polymerization and RAFT polymerization. The block copolymer reversibly formed and deformed micellar assemblies above the phase separation temperature (T_ps) of poly(NIPAM) block in water. This BVCT is not only functioned as an initiator, but also acted as a monomer. When BVCT was copolymerized with MOVE by living cationic polymerization, followed by graft copolymerization with NIPAM via RAFT polymerization, well-defined graft copolymers (MOVE_n-co-BVCT_m)-g-NIPAM_x (n = 62–73, m = 1–9, x = 19–214) were successfully obtained. However, no micelle formed in water above T_ps of poly(NIPAM) graft chain unlike the case of block copolymers.     

Runx1 Messenger RNA Delivered by Polyplex Nanomicelles Alleviate Spinal Disc Hydration Loss in a Rat Disc Degeneration Model

Vertebral disc degenerative disease (DDD) affects millions of people worldwide and is a critical factor leading to low back and neck pain and consequent disability. Currently, no strategy has addressed curing DDD from fundamental aspects, because the pathological mechanism leading to DDD is still controversial. One possible mechanism points to the homeostatic status of extracellular matrix (ECM) anabolism, and catabolism in the disc may play a vital role in the disease’s progression. If the damaged disc receives an abundant amount of cartilage, anabolic factors may stimulate the residual cells in the damaged disc to secrete the ECM and mitigate the degeneration process. To examine this hypothesis, a cartilage anabolic factor, Runx1, was expressed by mRNA through a sophisticated polyamine-based PEG-polyplex nanomicelle delivery system in the damaged disc in a rat model. The mRNA medicine and polyamine carrier have favorable safety characteristics and biocompatibility for regenerative medicine. The endocytosis of mRNA-loaded polyplex nanomicelles in vitro, mRNA delivery efficacy, hydration content, disc shrinkage, and ECM in the disc in vivo were also examined. The data revealed that the mRNA-loaded polyplex nanomicelle was promptly engulfed by cellular late endosome, then spread into the cytosol homogeneously at a rate of less than 20 min post-administration of the mRNA medicine. The mRNA expression persisted for at least 6-days post-injection in vivo. Furthermore, the Runx1 mRNA delivered by polyplex nanomicelles increased hydration content by ≈43% in the punctured disc at 4-weeks post-injection (wpi) compared with naked Runx1 mRNA administration. Meanwhile, the disc space and ECM production were also significantly ameliorated in the polyplex nanomicelle group. This study demonstrated that anabolic factor administration by polyplex nanomicelle-protected mRNA medicine, such as Runx1, plays a key role in alleviating the progress of DDD, which is an imbalance scenario of disc metabolism. This platform could be further developed as a promising strategy applied to regenerative medicine.