Phase-interpolated averaging for analyzing electroencephalography and magnetoencephalography epochs

Stimulus-locked averages of electroencephalography (EEG) and magnetoencephalography (MEG) epochs reveal characteristic waveforms. EEG/MEG generation models to have reconstruct such waveforms have been recently proposed. These models assume that evoked, phase-modulated, and amplitude-modulated activities occur solely or simultaneously. We propose a two-stage stimulus-locked averaging method, called phase-interpolated averaging, to investigate the EEG/MEG generation process. First, virtual EEG/MEG epochs, which would be obtained as if instantaneous phases for each time sampling point were on a phase-grid, are interpolated from actually measured EEG/MEG epochs. Then, the virtual EEG/MEG epochs are discrete Fourier transformed. A simulation revealed that the zeroth Fourier term revealed the evoked activity, the first Fourier term revealed the amplitude-modulated activity, and the condition number of the interpolation reflected the phase-modulated activity. On the basis of these facts, a preliminary EEG analysis implied that the evoked activity is much smaller than what would be expected by using conventional averaging, the evoked and phase-modulated activities simultaneously occur, and the amplitude-modulated activity occasionally associates with the evoked and phase-modulated activities. To the best of our knowledge, this is the first time that these three activities have been shown to coexist by actually separating them.     

Prediction of vortex penetration depth at thermal stratification by cavity flow in a branch pipe with closed end (effect of heat radiation condition on temperature fluctuations)

In a branch pipe with one closed end, the cavity flow penetrates into the branch pipe from the main loop and a thermal boundary layer occurs because the cavity flow is a hot fluid, but heat removal causes a colder fluid in the branch pipe. This thermal stratification may affect the structural integrity. Therefore, a pipe design standard to suppress thermal fatigue should be established. The pipe design standard consists of the maximum penetration depth L_sv and the minimum penetration depth L_sh. In order to establish an evaluation method for L_sh, a visualization test and a temperature fluctuation test were carried out. A theoretical formula for thermal stratification was introduced from the heat balance model. Then the model was used to obtain an empirical equation from the map of fluid temperature fluctuation. This method can predict the vortex penetration depth by cavity flow in horizontal branch pipes. © 2006 Wiley Periodicals, Inc. Heat Trans Asian Res, 36(1):38–55, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20135     

Charpy impact property related to {100} cleavage fracture in 15CrODS steel

Abstract

Based on the former results that delamination along {100} cleavage fracture leads to the improved absorbed energy, {100} cleavage plane was formed in parallel to the rolled plate by recrystallisation and cold roll processing in 15CrODS steel plate. Charpy impact properties were investigated in terms of notch direction against {100} cleavage plane. Notch with normal direction against {100} cleavage plane induced delamination fracture, but provided similar absorbed energy to that of conventional extruded bar. The transverse notch direction against {100} cleavage plane served higher absorbed energy at low temperature. Higher upper shelf energy and lower DBTT were attained in conventional hot extruded bar, which contains any crystallographic planes rotated around <110> axis at the transverse direction. The delamination fracture leading to high absorbed energy is significantly affected by a crystallographic morphology of the {100} cleavage plane perpendicular to transverse plane.     

Hydrogen economy assessment for long-term energy systems in Japan

An assessment is made of hydrogen technology development; in particular, economy as an energy carrier, applicability for end-uses and the potential of the market in the future. Specifically, rough static cost comparisons are made on several modes of electricity transmission and hydrogen transport, and on several ways of off-peak electricity saving; including energy storage in the form of hydrogen. Then, the quantity of oil that could be saved for some representative end-use sectors if hydrogen fuel were to be introduced is discussed. Finally, a potential market is assessed, by projecting overall future energy supply/demand dynamics in Japan.     

Numerical analysis of field-effect surface passivation for solar cells

In order to investigate the influence of surface potential on the electric characteristics of solar cells, the characteristics of conventional cells and back-contact type high-efficiency silicon cells were analyzed using 2-dimensional numerical simulation, varying the surface electrical potential. The locations where surface electrical potential is controlled are the rear side in conventional cells and the front side in back-contact cells. As a result of the calculations, it was found that field-effect surface passivation yields cell characteristics equivalent to those of a cell with effective surface recombination velocity of 0 cm/s, even if the cell has a poor interface (i.e., D_it > 1.0 × 10¹¹cm⁻²eV⁻¹). It was also found that both the use of a higher resistivity wafer and — especially in p-type substrates — the formation of inversion layers causes the field-effect surface passivation to work the fullest effect. In addition, a computer simulation based on physical-parameter measurements taken from actual materials forecasts that a back-contact cell would realistically be able to exceed 25% efficiency under AM1.5 global, one-sun illumination.     

Probing the interaction between a high-affinity single-chain Fv and a pyrimidine (6-4) pyrimidone photodimer by site-directed mutagenesis

We have used site-directed mutagenesis to uncover the origin of the binding affinity differences exhibited by a series of monoclonal antibodies that recognize pyrimidine (6-4) pyrimidone photoproducts in the context of single- or double-stranded DNA. In this study, we have focused on two antibodies-64M3 and 64M5-that share the same binding specificity but differ in their affinities. We used single-chain Fv (scFv) derivatives for these studies since they can be easily expressed in Escherichia coli. To facilitate this, we also developed a simple, on-column refolding procedure for scFvs that is rapid and does not require high dilution. We took several precautions to ensure that the scFvs faithfully reflected the behavior of the parent monoclonal antibodies. Results obtained from chimeric scFvs constructed from 64M3 and 64M5 suggested that the higher affinity of the 64M5 antibody was mainly due to its VL region. Loop-grafting studies in which VH CDR loops of 64M3 were individually transplanted into 64M5 were consistent with this hypothesis. Since the VL sequences of 64M3 and 64M5 differ at only three positions (L30, L50, and L90), alanine-scanning mutagenesis was used to assess the importance of these three residues in DNA binding by 64M5. These studies highlighted the importance of all three VL CDR loops; furthermore, they suggested that photoproduct binding involved conformational changes within the VL region.     

An Engineered Old Yellow Enzyme that Enables Efficient Synthesis of (4R,6R)‐Actinol in a One‐Pot Reduction System

(4R,6R)‐Actinol can be stereo‐selectively synthesized from ketoisophorone by a two‐step conversion using a mixture of two enzymes: Candida macedoniensis old yellow enzyme (CmOYE) and Corynebacterium aquaticum (6R)‐levodione reductase. However, (4S)‐phorenol, an intermediate, accumulates because of the limited substrate range of CmOYE. To address this issue, we solved crystal structures of CmOYE in the presence and absence of a substrate analogue p‐HBA, and introduced point mutations into the substrate‐recognition loop. The most effective mutant (P295G) showed two‐ and 12‐fold higher catalytic activities toward ketoisophorone and (4S)‐phorenol, respectively, than the wild‐type, and improved the yield of the two‐step conversion from 67.2 to 90.1 %. Our results demonstrate that the substrate range of an enzyme can be changed by introducing mutation(s) into a substrate‐recognition loop. This method can be applied to the development of other favorable OYEs with different substrate preferences.