Protective Role of Glutathione in the Hippocampus after Brain Ischemia

Stroke is a major cause of death worldwide, leading to serious disability. Post-ischemic injury, especially in the cerebral ischemia-prone hippocampus, is a serious problem, as it contributes to vascular dementia. Many studies have shown that in the hippocampus, ischemia/reperfusion induces neuronal death through oxidative stress and neuronal zinc (Zn²⁺) dyshomeostasis. Glutathione (GSH) plays an important role in protecting neurons against oxidative stress as a major intracellular antioxidant. In addition, the thiol group of GSH can function as a principal Zn²⁺ chelator for the maintenance of Zn²⁺ homeostasis in neurons. These lines of evidence suggest that neuronal GSH levels could be a key factor in post-stroke neuronal survival. In neurons, excitatory amino acid carrier 1 (EAAC1) is involved in the influx of cysteine, and intracellular cysteine is the rate-limiting substrate for the synthesis of GSH. Recently, several studies have indicated that cysteine uptake through EAAC1 suppresses ischemia-induced neuronal death via the promotion of hippocampal GSH synthesis in ischemic animal models. In this article, we aimed to review and describe the role of GSH in hippocampal neuroprotection after ischemia/reperfusion, focusing on EAAC1.     

Enzymatic properties and transglycosylation of α-galactosidase from Penicillium oxalicum SO

Penicillium oxalicum SO α-galactosidase demonstrated weak hydrolysing activity but a high rate of transglycosylation in the reaction with melibiose, where the major product was 6-α-galactosyl melibiose. The transfer ratio was 83.6% and was maintained over a long reaction time of 80 h. The molecular weight was estimated to be 124,000 by SDS–PAGE. The optimal pH was ∼3 and a stable pH, with a range of 2.4–9.5, was found. The optimal temperature was ∼60 °C and the activity was stable below 60 °C. With respect to acceptor specificity, mono-alcohols, sugar alcohols and sugars were poor acceptors, but the di-alcohol ethylene glycol and the tri-alcohol glycerin were good acceptors. The percentage of transglycosylation to glycerin increased up to 41.7%, as that to melibiose decreased, with the initial glycerin concentration of 40%. The production of α-d-galactosylglycerol was 293 mg for each gram of melibiose used by the enzymatic reaction.     

Threshold voltage roll-up/roll-off characteristic control insub-0.2-μm single workfunction gate CMOS for high-performance DRAMapplications

Threshold voltage (V_t) roll-off/roll-up control is a key issue to achieve high-performance sub-0.2-μm single workfunction gate CMOS devices for high-speed DRAM applications. It is experimentally confirmed that a combination of well RTA and N₂ implant prior to gate oxidation is important to reduce V_t roll-up characteristics both in nFET and pFET. Optimization of RTA conditions after source/drain (S/D) implant is also discussed as a means of improving V_t roll-off characteristics. Finally, the impact of halo implant on V_t variation in sub-0.2-μm buried channel pFETs is discussed. It is found that halo profile control is necessary for tight V_t variation in sub-0.2-μm single workfunction gate pFET     

Fundamental study of the radiation monitoring system based on evaluation of DNA lesions

The biological dosemeter that measures biological responses to ionising radiation is useful for radiation protection. This paper presents the development and characterisation of a gamma ray irradiation dosimetry system based on real-time PCR (polymerase chain reaction) methodology. Real-time PCR is used to amplify and simultaneously quantify a targeted DNA molecule. If there are no limitations due to limiting substrates or reagents, at each extension step, the amount of DNA target is doubled, leading to exponential (geometric) amplification of the specific DNA fragment. The essential point of this assay is that DNA lesions caused by ionising radiation block DNA synthesis by DNA polymerase, resulting in a decrease in the amplification of a damaged DNA template compared with that of non-damaged DNA templates.     

Multi-pillar surrounding gate transistor (M-SGT) for compact andhigh-speed circuits

The M-SGT has a three-dimensional structure, which consists of the source, gate, and drain arranged vertically. The gate electrode surrounds the crowded multipillar silicon islands. Because all the sidewalls of the pillars are used effectively as the transistor channel, the M-SGT has a high-shrinkage feature. The area occupied by the M-SGT can be shrunk to less than 30% of that occupied by the planar transistor. The small occupied area and the mesh-structured gate electrode lead to the small junction capacitance and the small gate electrode RC delay, resulting in high-speed operation. The fabrication of the M-SGT CMOS inverter chain is discussed. The propagation delay reduces to 40%, compared with the planar transistor inverter chain     

Precise position control of an ultrasonic motor using the PID controller combined with NN

The input‐output characteristic of an ultrasonic motor (USM) has nonlinear elements and changes with a temperature rise or fluctuation of load‐mass. Therefore, it is difficult to accomplish satisfactory control performance by using conventional PID controllers. In this paper, we propose a PID controller combined with a neural network (NN‐PID controller). In this design method, the controller gains consist of constant gains of the PID controller and variable gains of the NN controller. The weights of the NN are adjusted by the backpropagation method so that the control error can be minimized. This method does not require long learning time of the NN. The effectiveness of the proposed design method is confirmed by experiments using an existing USM. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 146(3): 46–54, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10199     

Fabrication of Elongated α-SiAlON via a Reaction-Bonding Process

A reaction-bonding process, which offers low sintering shrinkage and is a low-cost process, was applied to fabricate Y–α-SiAlON ceramics. The green compacts composed of Si, Y₂O₃, Al₂O₃, and AlN were nitrided and subsequently postsintered. Dense single-phase Y–α-SiAlON with elongated grain morphology could be achieved in the specimen postsintered at 1900°C. The material exhibited high hardness (1850 HV10) and high fracture toughness (5.1 MPa·m^1/2).     

Memory design using a one-transistor gain cell on SOI

A 512-kb memory has been developed featuring a one-transistor gain cell of size 7F/sup 2/ (F = 0.18 /spl mu/m) on SOI. The cell named the floating body transistor cell (FBC) has the ability to achieve a 4F/sup 2/ cell using self-aligned contact technologies and is proved to be scalable with respect to a cell signal. A basic operation was verified by device simulation and hardware measurement. An array driving method is disclosed which makes selective write possible. A cell signal sensing system consisting of a pair of reference cells written opposite data and comparing the combined current with the doubled cell current is shown to be robust against cell parameter variations in process and temperature. A random access time of 40 ns was simulated. Nondestructive readout and C/sub b//C/sub s/. free signal development drastically improve cell efficiency.     

Effect of the amount of excess oxides on the densification of α-SiAlON fabricated via a reaction-bonding process

Y-α-SiAlONs with elongated grains were fabricated via a reaction-bonding process using starting compositions containing excess oxides in the form of Y₂O₃ and SiO₂. The density of post-sintered specimens reached a maximum value with compositions containing 2 mass% excess oxides, although conventionally sintered materials of this composition were not fully dense. However for compositions containing smaller amounts of excess oxides, the density of the specimen fabricated via a reaction-bonding process was lower than that via a conventional process. In these samples it is thought that liquid phase sintering was difficult to be achieve during the post-sintering process, since the amount of SiO₂ contained in the starting powder was lower and the Al₂O₃ in the starting composition was consumed for the production of β-SiAlON during nitridation. There was also a decrease in density of the reaction-bonded materials with further increases in the amounts of additional oxides. For these samples the compacts could not be densified uniformly, because of non-uniformity of the phase composition in the nitrided compacts. The dense reaction bonded α-SiAlON with elongated grains, fabricated from compositions with 2 mass% excess oxides exhibited both high fracture toughness and high hardness.     

Impact of surrounding gate transistor (SGT) for ultra-high-densityLSI's

A transistor with compact structures for future MOS devices is discussed. This transistor, whose gate electrode surrounds the pillar silicon island, reduces the occupied area for all kinds of circuits. By using this transistor, the occupied area of the CMOS inverter can be shrunk to 50% of that using planar transistors. Other advantages, such as steep cutoff characteristics, very small substrate bias effects, and high reliability, are discussed. Its structure, which allows for the enlargement of gate-controllability to the channel and electric field relaxation at the drain edge, is described. The advantages of this SGT for large-scale integration (LSI) devices is discussed