[en] An upgrade of the MEG experiment, which searches for the lepton flavor violating decay, μ→eγ, at the highest sensitivity ever, is planned in order to improve the sensitivity down to ∼5×10⁻¹⁴. We plan to employ a stereo wire drift chamber with a unique volume for the tracking and a pixelated scintillation detector with silicon photomultiplier (SiPM) readout for the timing measurement with improved efficiency and resolutions. We will describe the expected performance and the R and D status of the new spectrometer especially focusing on the new timing counter, which is expected to contribute better resolution of the relative timing between positron and gamma-ray

[en] The enzymic conversion of proglobulin to globulin catalyzed by the extracts of vacuoles isolated from developing pumpkin (Cucurbita sp. cv Kurokawa Amakuri Nankin) cotyledons was investigated. The endoplasmic reticulum fraction isolated from the developing cotyledons pulse-labeled with [³⁵S]methionine was shown to contain mainly the radiolabeled proglobulin, which was used as a substrate for assaying the proteolytic processing in vitro. The vacuolar extracts catalyzed the proteolytic processing of the proglobulin molecule to produce globulin containing two kinds of polypeptide chains, γ and δ. The pH optimum for the vacuole-mediated conversion was at pH 5.0. The proteolytic processing of proglobulin by the vacuolar extracts was inhibited in the presence of various thiol reagents, e.g. p-chloromercuribenzoate, N-ethylmaleimide, iodoacetic acid, Hg²⁺, and Cu²⁺, but not phenylmethylsulfonyl fluoride, EDTA, o-phenanthroline, leupeptin, antipain, pepstatin, chymostatin, or pumpkin trypsin inhibitor, and was activated in the presence of dithiothreitol and cysteine, indicating that the processing enzyme is a thiol protease. The suborganellar fractionation of the vacuoles showed that the processing activity was localized in the matrix fraction, but not in the membrane or crystalloid fractions. During the seed development, the enzyme was shown to increase, exhibiting the maximal activity at the late developmental stage. The matrix fraction of the protein bodies isolated from the dry castor bean (Ricinus communis) exhibited the processing activity toward the pumpkin proglobulin molecules in the same manner as that by the matrix fraction of pumpkin vacuoles

[en] The authors made an explicit formula for beta-ray angular distribution by taking into account the radiative corrections, Coulomb corrections of the finite-size nucleus, weak magnetism, induced pseudoscalar, second-class induced tensor, and contributions of the d-wave leptons. Experimental data on the beta decays of aligned ¹²B and ¹²N given at Osaka are carefully investigated, and it is shown that these data are compatible with no induced tensor current, fsub(T)/fsub(A) = - (0.44 +- 0.88)/2M. The nuclear parameter y is 3.3 +- 0.9 in excellent agreement with the predicted value 3.6. (Auth.)

[en] The effect of ultraviolet or laser light on the growth of lobes in a green alga, Micrasterias thomasiana was investigated. During plasmolysis, the cell wall and the outermost region of the cytoplasm were separately irradiated with an ultraviolet or laser microbeam. Growth of the lobes was more effectively inhibited by irradiation of the cytoplasm than of the cell wall when the dose of irradiation was weak. Growth inhibition was observed in the irradiated cytoplasm where no apparent decrease in velocity of plasma streaming was seen, which suggested that irradiation caused more damage to the mechanism of exocytosis than to the migration of secretion vesicles. Strong irradiation resulted in gelatinization of the cytoplasm. With strong doses of irradiation on both the cytoplasm and cell wall, growth was completely inhibited. (author)

[en] An experimental investigation was conducted on convective heat transfer to a local blockage in a simulated subchannel of a Liquid Metal-cooled Fast Breeder Reactor. The experiment was performed with a 4-subchannel geometry water test facility. A porous blockage is located at the center subchannel and is surrounded by three unplugged subchannels. The blockages used in this study were solid metal, a porous blockage consisting of metal spheres, and a porous blockage with plates covering the side or top faces of the blockage to intentionally prevent either the axial and/or the lateral flows through the blockage. In the experiment, the heat flux provided by an electrical heater were set at 50(kW/m²) and 20(kW/m²) while the Reynolds number was varied from 3.5 x 10³ to 8.6 x 10³. Temperature measurements of the water were made inside/outside the blockage. Finally, velocity profiles outside the blockage were measured with a Laser Doppler Velocimeter (LDV) and an Ultrasound Velocity Profile monitor (UVP). Normalized temperature inside the blockage revealed that the influence of buoyancy was negligibly small, and that the temperature depended on the flow rate and the configurations of the blockage. Comparison of temperature and velocity profiles between the blockage types as shown in Fig. A-1, showed that both lateral and axial flow influenced the heat removal from inside the upper part of the porous blockage, as well as the heater surface contacting the blockage. Father, lateral flow had a strong influence on the peak temperature inside the blockage than axial flow. The heat transfer characteristics showed that the predominant mode of heat was not conduction, but convection via lateral flow through the blockage and axial flow through the upper region of the blockage under higher flow rate conditions

[en] Sodium experiments were conducted on core thermal-hydraulics simulating a scram transient of a large scale fast breeder reactor using the test facility PLANDTL-DHX with seven fuel subassemblies. The influence of inter-subassembly heat transfer on temperature distribution in the subassembly was revealed via measurements. The flow in the gap between neighboring subassemblies called inter-wrapper flow (IWF) was also studied in relation to its capability of cooling the subassemblies. A computational model is presented for predicting the transient without IWF. The multi-dimensional numerical analysis model employs an empirical correlation to simulate mixing effects between adjacent subchannels. It was shown that the present computational method could evaluate the transient behavior of thermal-hydraulics in the subassemblies accurately from forced to natural circulation accompanied by inter-subassembly heat transfer and flow redistribution in the subassembly. The cooling effects of IWF on the fuel subassemblies were found in spite of natural circulation flow reduction in the primary loop attributable to temperature decreases in the upper non-heated section in the core. The inter-wrapper flow can effectively cool the core under extreme conditions of low flow rates through the core.

[en] An analysis was made on the reactivity and the flux profile modulation caused by spatial random perturbations in the number densities of core materials of a bare, uniform, critical, reference reactor. Using an orthonormal function set of the Helmholtz modes, a one-group diffusion equation with the multiplication factor k is transformed into an infinite dimensional vector equation with the reactivity p = 1 - 1/k. The problem is then analyzed as the perturbations in the smallest eigenvalue in magnitude and the corresponding eigenvector of an infinite dimensional matrix. This approach leads to the conclusion that spatial random perturbations cause the positive reactivity effect and a flattened flux profile. The results are exact up to the second order of perturbations when zero ensemble average of perturbations is assumed, and are exact up to the third order of perturbations when the Gaussian distribution is assumed in addition. (author)

[en] The regulation of the CSF [Cl^-] plays a key role in CNS acid-base homeostasis. The authors have shown in previous studies that chloride influx from blood to CSF is largely dependent upon sodium-coupled carrier mediated movement. Therefore, the mechanism of chloride outflux from CSF to brain was evaluated in anesthetized dogs using ventricular-cisternal perfusion (VCP) with the short-lived isotope ³⁸Cl^- and dextran. The outflux of ³⁸Cl^- from CSF was determined from the different movements between ³⁸Cl^- and dextran using a one compartment model. VCP was performed at a rate of 1.4 ml/min for 14 min, and then slowed to 0.28 ml/min. The ³⁸Cl^- activity decreased to a steady state level about 12% lower than that of dextran within 40-50 minutes. Under control conditions (19 runs in 7 dogs), the rate of chloride outflux was 0.059 +/- 0.004 min^-1 (mean +/- SE). It was not significantly changed after the inclusion of bumetanide (10^-5 molar) in the VCP fluid (n=6), which inhibits sodium-coupled Cl^- transport, or with acetazolamide 4.5 x 10^-3 molar (n=4) which inhibits carbonic anhydrase. The authors conclude that chloride outflux from CSF is not dependent upon sodium-coupled carrier mediated movement, which is in contrast with chloride influx from blood to CSF, nor is it dependent upon carbonic anhydrase activity

[en] None

[en] This paper describes experimental and simulation studies on the effects of external heating and magnetic field on the transition process, for development of thermally and magnetically contolled superconductive power switches. The simulation results by the model agree with the experimental ones, which enables one to obtain several quantities such as the distribution of temperature or resistance, and to infer the effects of external magnetic field. (author)