Effects of isoflurane on in vivo release of acetylcholine in the rat cerebral cortex and striatum

BACKGROUND: Acetylcholine (ACh) is one of the major excitatory neurotransmitters in the central nervous system, and changes in neural activity induced by anesthesia alter the release of ACh. However, the effects of isoflurane, one of the most widely used volatile anesthetics, on ACh release are not known. The present study attempts to clarify the dose-effect relationship of isoflurane on the in vivo release of ACh in rat brains. METHODS: Changes in the extracellular concentration of ACh and choline in the cerebral cortex and striatum induced by 0.5, 1.0, and 1.5 minimum alveolar concentration (MAC) of isoflurane were determined using a brain microdialysis technique. RESULTS: In the cortex, the ACh release decreased to 30.8+/-10.1 (mean+/-SEM), 10.2+/-4.1, and 8.1+/-2.9% of basal value by increasing doses of isoflurane, and in the striatum, to 73.3+/-4.4, 49.2+/-4.2, and 40.7+/-4.5%. The ACh release rapidly recovered control levels with the discontinuance of isoflurane. Choline concentration was not changed significantly by isoflurane except for a decrease to 74.8+/-4.6% in the striatum by 0.5 MAC. In both the cortex and striatum, the choline concentration decreased with the discontinuance of isoflurane to 70.3+/-13.3, and 68.2+/-5.4%, respectively. CONCLUSION: The fact that all classic anesthetics reported previously, as well as isoflurane, reduce ACh release supports the hypothesis that the suppression of cholinergic cells is, at least in part one of the mechanisms of anesthesia.     

High-resolution elemental mapping of titanium oxide/aluminium oxide multilayer by spectrum-imaging

A spectrum-imaging technique based on scanning transmission electron microscopy combined with an electron energy-loss spectroscopy has been applied for the multilayer of amorphous titanium oxide and aluminium oxide layers on silicon substrate. We demonstrate the high-resolution elemental mapping and discuss the advantage of this method compared to an energy-filtering transmission electron microscopy. The main advantage is the absence of chromatic broadening, which allows the use of a large collection angle to acquire spectrum-image data and a wide energy window to integrate the core-loss signals. This suggests that the spatial resolution of elemental maps is mainly determined by the size of the electron probe.     

Vapor Pressure Measurements of Lanthanum–Bismuth Alloys by Mass-Spectrometric Method1

Vapor pressures of Bi₂ (g) over La_0.03 Bi_0.97 and two-phase mixtures of Bi+LaBi₂, LaBi₂+LaBi, LaBi+La₄Bi₃, La₄Bi₃+La₅Bi₃, and La₅Bi₃+La₂ Bi were measured in the temperature range from 795 to 1066K with a time-of-flight mass spectrometer equipped with a tungsten Knudsen cell. The vapor pressure of Bi₂(g) over the two-phase mixtures of La₂Bi+La could not be detected experimentally in this temperature range. The thermodynamic activity of bismuth was determined from the vapor pressure of Bi₂(g). Thermodynamic activities of lanthanum over alloys were derived from those of bismuth in the alloys in this study and that of lanthanum in the bismuth in a previous study by graphic integration of the Gibbs–Duhem equation. Thermodynamic quantities such as Gibbs free energy of formation, excess enthalpy, etc., were also calculated from the thermodynamic activities.     

Semiconducting–Insulating Transition for Highly Donor-Dopod Barium Titanate Ceramics

BaTiO₃ ceramics doped with La (0.01–0.84 at.%) were prepared only with the addition of La and stoichiometric TiO₂. As a result, even when BaTiO₃ was doped with 0.53 at.% La, it could be converted to a semiconductor by sintering at 1540°C for 2 h in air and cooled slowly in the furnace. Differential thermal analysis data clearly demonstrated that the Curie point in the materials shifted toward lower temperatures with increased content of La substituted at the Ba site up to a critical concentration that varied with the sintering temperature. The obtained results suggest that the semiconducting–insulating transition for highly donor-doped BaTiO₃ was closely related to the incorporation of donor into the grains and to the resultant grain size, which were significantly affected by the sinterability of the BaTiO₃ starting powders and sintering conditions used.     

Near-infrared high-power LED's with Ga1-xAlxAs epitaxially grown junctions

This paper reports on a study of several techniques of fabricating an efficient Ga1-xAlxAs IRED with high power. Smooth epitaxial layers are grown on a substrate containing a thick Ga1-xAlxAs epitaxial layer which is used to form a hemispherical emitting surface. This is achieved by using a melting-back technique without up-heating. An effect of the AlAs molefraction ratio between n- and p-type regions was clearly found by measurement of a large number of diode chips, and the best performances were obtained on the junctions with the ratioX_{n}/X_{p} simeq 1.5. Ohmic contacts to the p and n regions were applied on the same surface of the wafer using only one metallic source for the vacuum deposition. A cerium-oxide film serves as an antireflection coating when deposited on the hemispherical surface and increases the optical output power by more than 30 percent. External quantum efficiencies of 28 percent (current density: 400 A/ cm²) and optical output power of 96 mW (drive current: 300 mA, current density: 1500 A/cm²) have been observed from diodes emitting at 8300 Å under dc operation at room temperature.     

Maximum entropy decomposition of flux distribution at steady state to elementary modes

Enzyme Control Flux (ECF) is a method of correlating enzyme activity and flux distribution. The advantage of ECF is that the measurement integrates proteome data with metabolic flux analysis through Elementary Modes (EMs). But there are a few methods of effectively determining the Elementary Mode Coefficient (EMC) in cases where no objective biological function is available. Therefore, we proposed a new algorithm implementing the maximum entropy principle (MEP) as an objective function for estimating the EMC. To demonstrate the feasibility of using the MEP in this way, we compared it with Linear Programming and Quadratic Programming for modeling the metabolic networks of Chinese Hamster Ovary, Escherichia coli, and Saccharomyces cerevisiae cells. The use of the MEP presents the most plausible distribution of EMCs in the absence of any biological hypotheses describing the physiological state of cells, thereby enhancing the prediction accuracy of the flux distribution in various mutants.     

APPLICABILITY OF CREEP CONSTITUTIVE EQUATIONS TO CREEP CURVES UNDER CONSTANT LOAD

1.IntroductionRecently,creepconstitutiveequationswhichcandescribeatotalcreepcurvecontainingatertiarycreepstagehavebeendevelopedtodesignhigh--temperaturecomponentsandtopredicttheirlives.Thetypicalmethodsarethe0projectionmethod[1--4]andnmethod[5--8].Inthe0projectionmethod,acreepcurveisexpressedasasumofadecayingprimarycreepandanacceleratingtertiarycreep.Creepstrain,scisdescribedasacombinationofthetwoexponentialtermsassc==01{1--exp(--02t)} 03{exp(04t)--1},(l)wheretistime,01,02,03and04areparameterc…     

Chlorination of UO2 and (U,Zr)O2 solid solution using MoCl5

Conversion of UO₂ and (U_0.5Zr_0.5)O₂ solid solution into chlorides by MoCl₅ was performed in order to confirm the applicability of the chlorination by MoCl₅ to a pretreatment of fuel debris by pyrochemical methods. Chlorination of (U_0.5Zr_0.5)O₂ powders and dense pieces was successfully achieved at 573 and 773 K, respectively, based on the following chemical reaction: 2(U_0.5Zr_0.5)O₂ + 4MoCl₅ = UCl₄ + ZrCl₄ + 4MoOCl₃. Rough separation of MoCl₅, ZrCl₄ and MoOCl₃ from UCl₄ was achieved by volatilization under temperature gradient. From these results, fundamental feasibility of the chlorination method using MoCl₅ as a pretreatment of fuel debris was shown.     

Algorithm tuners for PSO methods and genetic programming techniques for learning tuning rules

In recent years, improvements in processing power have allowed the application of optimization methods to complicated large optimization problems. Among these methods, heuristic optimization techniques such as particle swarm optimization (PSO) have been a particular focus of attention because of their simplicity, performance, and easy software implementation. However, there is no solid theoretical foundation for analyzing the convergence of these algorithms, and in practice, their rate of convergence is often determined by the choice of parameters. For this reason, the algorithm's parameters must be tuned appropriately for each new optimization problem we want to solve, and in some cases the parameters must be varied as the algorithm is updated. In this paper, we combine a feedback element as an algorithm tuner with an original algorithm; the resulting algorithm is applied to the optimization problem in question, and we use genetic programming (GP) to generate tuning rules to automatically tune the algorithm, according to its current state, as the algorithm is updated. More specifically, we adopt PSO as a heuristic optimization method, and we augment PSO by using GP as a meta‐algorithm to solve the learning problem of automatically generating tuning rules for the parameters in the PSO algorithm. This leads to the proposed method for generating parameter tuning rules to solve optimization problems more efficiently. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.