In Vivo Electrophysiology of Peptidergic Neurons in Deep Layers of the Lumbar Spinal Cord after Optogenetic Stimulation of Hypothalamic Paraventricular Oxytocin Neurons in Rats

The spinal ejaculation generator (SEG) is located in the central gray (lamina X) of the rat lumbar spinal cord and plays a pivotal role in the ejaculatory reflex. We recently reported that SEG neurons express the oxytocin receptor and are activated by oxytocin projections from the paraventricular nucleus of hypothalamus (PVH). However, it is unknown whether the SEG responds to oxytocin in vivo. In this study, we analyzed the characteristics of the brain–spinal cord neural circuit that controls male sexual function using a newly developed in vivo electrophysiological technique. Optogenetic stimulation of the PVH of rats expressing channel rhodopsin under the oxytocin receptor promoter increased the spontaneous firing of most lamina X SEG neurons. This is the first demonstration of the in vivo electrical response from the deeper (lamina X) neurons in the spinal cord. Furthermore, we succeeded in the in vivo whole-cell recordings of lamina X neurons. In vivo whole-cell recordings may reveal the features of lamina X SEG neurons, including differences in neurotransmitters and response to stimulation. Taken together, these results suggest that in vivo electrophysiological stimulation can elucidate the neurophysiological response of a variety of spinal neurons during male sexual behavior.     

Comparisons of Two Models for the Simulation of a DC Arc Plasma Torch

The hypothesis of local thermal equilibrium (LTE) in thermal plasma has been widely accepted. Most of the simulation models for the arc plasma torch are based on the hypothesis of LTE and its results indicate good validity to mimic the pattern of plasma flow inside a plasma torch. However, according to the LTE hypothesis, electrical conductivity near electrodes is significantly lower because of the low gas temperature. Consequently, it is difficult for electrical current flows to pass between the anode and cathode. Therefore, the key subject for a model concentrating on the LTE assumption is to deal with the low electrical conductivity near the electrodes. In this study, two models determining the electrical conductivity at the vicinity of the electrodes with two different assumptions were used to calculate the flow patterns inside a non-transferred DC arc plasma torch. Gas temperature, velocity, voltage drop, and heat energy of the plasma arc were compared between the two models. The results indicated that the plasma arc inside the plasma torch fluctuates, as simulated by both models. It seems that the model can obtain comparable accuracy with the experimental results if the plasma gas electrical conductivity is determined by nominal electron temperature.     

Development of novel temperature-stable Al2O3–TiO2-based dielectric ceramics featuring superior thermal conductivity for LTCC applications

A new composition was developed using sintering to improve the dielectric properties of low-temperature co-fired alumina (LTCA) containing CuO–TiO₂–Nb₂O₅–Ag₂O. By substituting some alumina with rutile TiO₂, the second-phase compound could be changed from AgNbO₃ to the rutile phase. Further, low-temperature sintering at temperatures below 960 °C was possible, suppressing Al₂TiO₅ formation during firing. The dielectric characteristics, particularly the temperature coefficient of the resonant frequency (τ_f) and Q × f values, were improved without significantly reducing the sinterability and thermal conductivity. The dielectric properties of the developed 88Al₂O₃–12TiO₂-based ceramic were ε_r: 14.7, τ_f: +0.8 ppm/K, and Q × f: 13,383 GHz (at ～10 GHz) at a firing temperature of 940 °C. The thermal conductivity was 18.5 W/mK, which is the highest value for reported temperature-stable low-temperature co-fired ceramics (LTCCs). These results provide one of the key technologies for the practical application of LTCCs with superior thermal conductivities.     

Preparation and mechanical properties of polystyrene–clay hybrids

Polystyrene–clay hybrids (PSCHs) were prepared by melt blending a styrene vinyloxazoline copolymer with organophilic clay. In the PSCHs, the silicate layers of the clay were delaminated and dispersed homogeneously to the nanometer level. The moduli of the PSCHs were higher than that of the PS copolymer. For example, the tensile modulus of the PSCH with 5 wt % clay was 1.4 times higher compared to that of the PS copolymer. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 3359–3364, 1999     

Detection of Verotoxigenic Escherichia coli O157 and O26 in food by plating methods and LAMP method: a collaborative study

In order to establish a rapid and sensitive method for the detection of Verotoxigenic Escherichia coli O157 and O26, a collaborative study was conducted focusing on a comparison of the efficiency of loop-mediated amplification (LAMP) assay targeting the Verocytotoxin (also called Shiga toxin) gene, utilizing a direct plating method and a plating method with immunomagnetic separation (IMS-plating method) using various agar media. In combination with enrichment with the modified EC supplemented with novobiocin, E. coli O157 was detected in most samples of ground beef and alfalfa sprouts by LAMP assay, the direct plating method and the IMS-plating method. E. coli O26 was detected in approximately 100% of the food samples by LAMP assay. However, the IMS-plating and direct plating methods recovered 80 and 50% in ground beef samples, respectively. As a result, it was demonstrated the LAMP assay is superior to the IMS-plating method. Based on these results, it appears LAMP assay is effective as a screening assay to detect E. coli O157 and O26 from positive samples.     

Functional analyses of neutrophil-like differentiated cell lines under a hyperglycemic condition

Diabetic patients are prone to severe bacterial infections. The functional alterations of neutrophils by hyperglycemia are thought to be partially responsible for such infections. In this study, we investigated the functional changes of neutrophil-like differentiated cell lines (dHL-60, dTHP-1, and dNB-4) by treatment with 5.5 mM, 11 mM, or 35 mM of glucose. In dHL-60 cells, the incubation with high glucose (35 mM) resulted in the enhancement of cell aggregation, the suppression of cellular fragility, the induction of reactive-oxygen species (ROS) production by phorbol myristate acetate (PMA) stimulation, and the impairment of phagocytosis. In dTHP-1 cells, the treatment with higher glucose generated the suppression of cellular fragility and extremely impaired phagocytosis (by 35 mM), and induced ROS production due to PMA stimulation (by 11 mM). Furthermore, the higher glucose exposure to dNB-4 cells enlarged intracellular vacuoles (by 35 mM) and induced ROS production due to PMA stimulation (by 11 mM). Since the ROS generation of those cells was enhanced only after PMA stimulation under the higher glucose conditions, glucose may have a priming effect rather than a triggering effect. These extraordinary sensitivities caused by the higher glucose treatments may reflect the dysfunction or overactivation of neutrophils.     

Influence of a fiber-network microstructure of paper-structured catalyst on methanol reforming behavior

A novel microstructured catalyst that consists of Cu/ZnO catalyst powders and ceramic fibers was successfully prepared using pulp fibers as a tentative matrix by a papermaking technique. As-prepared material, called a paper-structured catalyst, possessed porous microstructure with layered ceramic fiber networks (average pore size ca. 20 μm, porosity ca. 50%). In the process of methanol autothermal reforming (ATR) to produce hydrogen, paper-structured catalysts demonstrated both high methanol conversion and low concentration of undesirable carbon monoxide as compared with catalyst powders and pellets. The catalytic performance of paper-structured catalysts depended on the use of pulp fibers, which were added in the paper-forming process and finally removed by thermal treatment before ATR performance tests. Confocal laser scanning microscopy and mercury intrusion analysis suggested that the tentative pulp fiber matrix played a significant role in regulating the fiber-network microstructure inside paper composites. Various metallic filters with different average pore sizes, used as supports for Cu/ZnO catalysts, were subjected to ATR performance tests for elucidating the pore effects. The tests indicated that the pore sizes of catalyst support had critical effects on the catalytic efficiency: the maximum hydrogen production was achieved by metallic filters with an average pore size of 20 μm. These results suggested that the paper-specific microstructures contributed to form a suitable catalytic reaction environment, possibly by promoting efficient diffusion of heat and reactants. The paper-structured catalyst with a regular pore microstructure is expected to be a promising catalytic material to provide both practical utility and high efficiency in the catalytic gas-reforming process.     

Implementation of Fault-Tolerant GridRPC Applications

A task parallel application is implemented with Ninf-G, a GridRPC system. A series of experiments are conducted on the Grid testbed in Asia Pacific for three months. Through tens of long executions, typical fault patterns were collected, and instability of the network throughput was determined to be a major reason of the faults. Several important points are stressed to avoid task throughput decline due to the fault-recovery operations: Timeout minimization for fault detection, background recovery, redundant task assignments, and so on. This study also issues a steer for design of the automated fault-tolerant mechanism in an upper layer of the GridRPC framework.     

Enhancement of the thermoelectric figure of merit in p- and n-type Cu/Bi-Te/Cu composites

The resultant thermoelectric properties of welded Cu/Bi-Te/Cu composites were measured at 298 K as a function of relative thickness x of Bi-Te compound by changing the interval s between two thermocouples and compared with those calculated as a function of x by treating it as an electrical and thermal circuit. These composites were prepared by welding with eutectic solder of Pb-Sn, after one end surface of the as-grown p- and n-type Bi-Te ingots were plated with Ni. It was found that the observed ZT of composites has a local maximum at an optimum x even when s was changed, as in the case of Cu/Bi-Sb/Cu and Ni/Bi-Sb/Ni composites with various relative thicknesses. Appearance of a local maximum in ZT is owing to the barrier thermo-emf generated by a sharp temperature drop at the interface between Bi-Te compound and copper. It may be caused by the separation of non-equilibrium carriers at the interface between them. The observed maximum ZT values at 298 K of the p- and n-type composites reached surprisingly great values of 1.53 and 1.66 at x=0.98, which correspond to about twice as large as those of commercially utilized Bi-Te compounds. This enhancement of ZT is available for generators, but may be not utilizable as a Peltier module. The composite materials were thus found to be utilizable as useful means of further increase in ZT of macroscopic bulk materials.