On the Nonuniformity in Fluidized Bed

Mean (μc) and variance (σ) of local particle concentration in fluidized bed were measured by capacitance probe method using integrator and vacuum tube thermocouple. Particle concentration in bubble and dense phases (cb and cd), rise velocity of bubble (ub), bubble thickness (y) and its frequency (f) were also measured from the signal current recorded on oscillograms. The effects of fluidizing conditions on μc and σ were studied. In the bulk of bed, μc remains at a value fixed by the fluidizing conditions. It decreases with air velocity. σ, on the other hand, increases with probe level up to considerably higher portion of bed and there arrives at a constant value which increases with bed height and air velocity. The following equation was introduced to represent μc by the fluidizing characteristics. μc=yf/ubcb+(1-yf/ub)cd μc calculated by this equation coincides well with the measured μc. A regression equation of σ upon fluidizing characteristics, σ=0.72{yf/ub(1-yf/ub)}⁰.⁴⁶(cd-cb)².⁸⁹ was obtained, and the statistical analyses on this equation revealed that σ changes chiefly with (cd-cb), and accordingly, σ represents the nonuniformity in fluidized bed mainly in the form of particle concentration difference between bubble and dense phases

A case of gastric granular cell tumor

We herein describe an extremely rare case of gastric granular cell tumor (GCT). The gastric submucosal tumor showed a central tiny depression on the surface with a molar tooth-like appearance on esophagogastroduodenoscopy. Our case highlights that gastric GCT should be considered as differential diagnosis of gastric submucosal tumors

Status of the short-lived radioisotope supplying platform in Japan

The Short-Lived Radioisotope Supplying Platform in Japan has supplied various RIs for promoting the usage of RIs in broad field of science since 2016. The number of research programs is growing reflecting the increasing importance of the use of RIs. We continue supporting the research programs with the efforts of increasing the supply capacity

Ground-state properties of neutron-rich Mg isotopes

We analyze recently-measured total reaction cross sections for 24-38Mg isotopes incident on 12C targets at 240 MeV/nucleon by using the folding model and antisymmetrized molecular dynamics(AMD). The folding model well reproduces the measured reaction cross sections, when the projectile densities are evaluated by the deformed Woods-Saxon (def-WS) model with AMD deformation. Matter radii of 24-38Mg are then deduced from the measured reaction cross sections by fine-tuning the parameters of the def-WS model. The deduced matter radii are largely enhanced by nuclear deformation. Fully-microscopic AMD calculations with no free parameter well reproduce the deduced matter radii for 24-36Mg, but still considerably underestimate them for 37,38Mg. The large matter radii suggest that 37,38Mg are candidates for deformed halo nucleus. AMD also reproduces other existing measured ground-state properties (spin-parity, total binding energy, and one-neutron separation energy) of Mg isotopes. Neutron-number (N) dependence of deformation parameter is predicted by AMD. Large deformation is seen from 31Mg with N = 19 to a drip-line nucleus 40Mg with N = 28, indicating that both the N = 20 and 28 magicities disappear. N dependence of neutron skin thickness is also predicted by AMD.Comment: 15 pages, 13 figures, to be published in Phys. Rev.

Functional deficiency of MHC class i enhances LTP and abolishes LTD in the nucleus accumbens of mice

Major histocompatibility complex class I (MHCI) molecules were recently identified as novel regulators of synaptic plasticity. These molecules are expressed in various brain areas, especially in regions undergoing activity-dependent synaptic plasticity, but their role in the nucleus accumbens (NAc) is unknown. In this study, we investigated the effects of genetic disruption of MHCI function, through deletion of β2-microblobulin, which causes lack of cell surface expression of MHCI. First, we confirmed that MHCI molecules are expressed in the NAc core in wild-type mice. Second, we performed electrophysiological recordings with NAc core slices from wild-type and β2-microglobulin knock-out mice lacking cell surface expression of MHCI. We found that low frequency stimulation induced long-term depression in wild-type but not knock-out mice, whereas high frequency stimulation induced long-term potentiation in both genotypes, with a larger magnitude in knock-out mice. Furthermore, we demonstrated that knock-out mice showed more persistent behavioral sensitization to cocaine, which is a NAc-related behavior. Using this model, we analyzed the density of total AMPA receptors and their subunits GluR1 and GluR2 in the NAc core, by SDS-digested freeze-fracture replica labeling. After repeated cocaine exposure, the density of GluR1 was increased, but there was no change in total AMPA receptors and GluR2 levels in wildtype mice. In contrast, following repeated cocaine exposure, increased densities of total AMPA receptors, GluR1 and GluR2 were observed in knock-out mice. These results indicate that functional deficiency of MHCI enhances synaptic potentiation, induced by electrical and pharmacological stimulation

Evolution of the dynamic changes in functional cerebral oxidative metabolism from tissue mitochondria to blood oxygen

The dynamic properties of the cerebral metabolic rate of oxygen consumption (CMR O2 ) during changes in brain activity remain unclear. Therefore, the spatial and temporal evolution of functional increases in CMR O2 was investigated in the rat somato-sensory cortex during forelimb stimulation under a suppressed blood flow response condition. Temporally, stimulation elicited a fast increase in tissue mitochondria CMR O2 described by a time constant of B1 second measured using flavoprotein autofluorescence imaging. CMR O2 -driven changes in the tissue oxygen tension measured using an oxygen electrode and blood oxygenation measured using optical imaging of intrinsic signal followed; however, these changes were slow with time constants of B5 and B10 seconds, respectively. This slow change in CMR O2 -driven blood oxygenation partly explains the commonly observed post-stimulus blood oxygen level-dependent (BOLD) undershoot. Spatially, the changes in mitochondria CMR O2 were similar to the changes in blood oxygenation. Finally, the increases in CMR O2 were well correlated with the evoked multi-unit spiking activity. These findings show that dynamic CMR O2 calculations made using only blood oxygenation data (e.g., BOLD functional magnetic resonance imaging (fMRI)) do not directly reflect the temporal changes in the tissue's mitochondria metabolic rate; however, the findings presented can bridge the gap between the changes in cellular oxidative rate and blood oxygenation

Study of hadron interactions in a lead-emulsion target

Topological and kinematical characteristics of hadron interactions have been studied using a lead-emulsion target exposed to 2, 4 and 10 GeV/c hadron beams. A total length of 60 m $\pi^-$ tracks was followed using a high speed automated emulsion scanning system. A total of 318 hadron interaction vertices and their secondary charged particle tracks were reconstructed. Measurement results of interaction lengths, charged particle multiplicity, emission angles and momenta of secondary charged particles are compared with a Monte Carlo simulation and appear to be consistent. Nuclear fragments emitted from interaction vertices were also detected by a newly developed emulsion scanning system with wide-angle acceptance. Their emission angle distributions are in good agreement with the simulated distributions. Probabilities of an event being associated with at least one fragment track are found to be greater than 50% for beam momentum $P > 4$ GeV/c and are well reproduced by the simulation. These experimental results validate estimation of the background due to hadron interactions in the sample of $\tau$ decay candidates in the OPERA $\nu_{\mu} \to \nu_{\tau}$ oscillation experiment.Comment: 14 pages, 11 figure

Layer-specific fMRI responses to excitatory and inhibitory neuronal activities in the olfactory bulb

High-resolution functional magnetic resonance imaging (fMRI) detects localized neuronal activity via the hemodynamic response, but it is unclear whether it accurately identifies neuronal activity specific to individual layers. To address this issue, we preferentially evoked neuronal activity in superficial, middle, and deep layers of the rat olfactory bulb: the glomerular layer by odor (5% amyl acetate), the external plexiform layer by electrical stimulation of the lateral olfactory tract (LOT), and the granule cell layer by electrical stimulation of the anterior commissure (AC), respectively. Electrophysiology, laser-Doppler flowmetry of cerebral blood flow (CBF), and blood oxygenation level-dependent (BOLD) and cerebral blood volume-weighted (CBV) fMRI at 9.4 T were performed independently. We found that excitation of inhibitory granule cells by stimulating LOT and AC decreased the spontaneous multi-unit activities of excitatory mitral cells and subsequently increased CBF, CBV, and BOLD signals. Odor stimulation also increased the hemodynamic responses. Furthermore, the greatest CBV fMRI responses were discretely separated into the same layers as the evoked neuronal activities for all three stimuli, whereas BOLD was poorly localized with some exception to the poststimulus undershoot. In addition, the temporal dynamics of the fMRI responses varied depending on the stimulation pathway, even within the same layer. These results indicate that the vasculature is regulated within individual layers and CBV fMRI has a higher fidelity to the evoked neuronal activity compared with BOLD. Our findings are significant for understanding the neuronal origin and spatial specificity of hemodynamic responses, especially for the interpretation of laminar-resolution fMRI. © 2015 the authors115151sciescopu