Preliminary study of the tight lattice pressured heavy water reactor loaded with Pu／U and Th／U mixed fuels

To improve nuclear fuel utilization efficiency and prolong fuel cycle burn-up,a tight ptich lattice pressured heavy water reactor was investigated as an alternative of next generation of power reactors.It is shown that the high conversion ratio and negative coolant void reactivity coefficient are challenges in the reactor core physics designs.Various techniques were proposed to solve these problems.In this work.a tight pitch lattice and mixed fuel assemblies pressured heavy water reactor concept was investigated.BY utilizing numerical simulation technique,it is demonstrated that reactor core mixed with Pu/U and Th/U assemblies can achieve high conversion ratio(0.98) ,long burn-up(60GWD/t)and negative void reactivity coefficients.     

Force sensorless robust tracking servo system suppressing periodic disturbance and sudden disturbance for optical disk system

This paper proposes a new force sensorless robust tracking servo system, which detects and suppresses both the periodic disturbance and the sudden disturbance without force sensor. The proposed system estimates both the periodic disturbance and the sudden disturbance and the sudden disturbance by using a new sudden disturbance observer and the memory of tracking error. In the proposed system, the influence of sudden disturbance is suppressed by the proposed sudden disturbance observer. On the other hand, the influence of periodic disturbance is suppressed by means of ZPET feed‐forward servo system. The experimental results point out that the proposed tracking servo system has a precise tracking response against both the periodic disturbance and the sudden disturbance. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 166(1): 82–90, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20614     

Power reduction techniques for a 1-Mb ECL-CMOS SRAM with an accesstime of 550 ps and an operating frequency of 900 MHz

This paper describes power reduction circuit techniques in an ultra-high-speed emitter-coupled logic (ECL)-CMOS SRAM. Introduction of a 0.25-μm MOS transistor allows a Y decoder and a bit-line driver to be composed of CMOS circuits, resulting in a power reduction of 34%. Moreover, a variable-impedance load has been proposed to reduce cycle time. A 1-Mb ECL-CMOS SRAM was developed by using these circuit techniques and 0.2-μm BiCMOS technology. The fabricated SRAM has an ultrafast access time of 550 ps and a high operating frequency of 900 MHz with a power dissipation of 43 W     

The Effectiveness of Fish Oil Supplementation in Asthmatic Rats is Limited by an Inefficient Action on ASM Function

Episodes of acute exacerbation are the major clinical feature of asthma and therefore represent an important focus for developing novel therapies for this disease. There are many reports that the n-3 fatty acids found in fish oil exert anti-inflammatory effects, but there are few studies of the action of fish oil on airway smooth muscle (ASM) function. In the present investigation, we evaluated the effect of fish oil supplementation on smooth muscle force of contraction in ovalbumin-induced asthmatic Wistar rats, and its consequences on static lung compliance, mucus production, leukocyte chemotaxis and production of proinflammatory cytokines. Fish oil supplementation suppressed the infiltration of inflammatory cells into the lung in asthmatic animals (2.04 ± 0.19 × 10⁶ cells vs. 3.33 ± 0.43 × 10⁶ cells in the control asthmatic group; P < 0.05). Static lung compliance increased with fish oil supplementation in asthmatic rats (0.640 ± 0.053 mL/cm H₂O vs. 0.399 ± 0.043 mL/cm H₂O; P < 0.05). However, fish oil did not prevent asthma-associated lung eosinophilia and did not affect the concentrations of tumor necrosis factor-α and interleukin-1β in lung tissue or the proportion of the airways obliterated with mucus. Fish oil had no effect on the force of contraction in asthmatic rats in response to acetylcholine (3.026 ± 0.274 mN vs. 2.813 ± 0.364 mN in the control asthmatic group). In conclusion, although fish oil exerts some benefits in this model of asthma, its effectiveness appears to be limited by an inefficient action on airway smooth muscle function.     

Combined effects of radon inhalation and antioxidant vitamin administration on acute alcohol-induced hepatopathy in mice

It has been reported that radon inhalation activates antioxidative functions in liver and has an antioxidative effect against hepatopathy similar to that of the antioxidative effects of ascorbic acid (VC) or α-tocopherol (VE). In this study, we examined the combined effects of radon inhalation and antioxidant vitamin administration on acute alcohol-induced hepatopathy in mice. ICR mice were subjected to intraperitoneal (i.p.) administration of alcohol after pretreating with air only (sham) or radon at a concentration of approximately 2000 Bq/m³ for 24 hours and i.p. administration of VC (300 mg/kg body weight) or VE (300 mg/kg body weight). In mice injected with alcohol, the combined radon and antioxidant vitamins treatment significantly decreased the activities of glutamic oxaloacetic transaminase in serum compared to not only the alcohol-administered group (sham group), but also the radon inhalation with alcohol administration group or the vitamin and alcohol administration group. In addition, radon inhalation significantly increased the antioxidant level, in such as the catalase activity and the total glutathione content in liver compared to the sham group. These results suggested that the combined radon and antioxidant vitamin treatment could effectively inhibit alcohol-induced hepatopathy in mice without any antagonizing action.     

Allixin, a phytoalexin produced by garlic, and its analogues as novel exogenous substances with neurotrophic activity

Effects of allixin, a phytoalexin of garlic, and its analogues were studied on the survival and morphology of primary cultured neurons from fetal rat brain. Addition of allixin (1-100 ng/ml) to medium significantly promoted the survival of neurons derived from various regions of brain and increased the number of branching points per axon in hippocampal neurons. Allixin, however, was cytotoxic at higher concentrations (>1 microg/ml). Among the analogues of allixin, 2,6-dimethyl-3-hydroxy-4H-pyran-4-one (DHP) possessed potent neurotrophic activity at concentrations over 10 ng/ml without any obvious cytotoxicity up to 10 microg/ml. DHP also retained the activity to promote axonal branching. These results indicate that DHP is a novel exogenous low molecular weight neurotrophic substance without apparent cytotoxicity. This compound may be a useful prototype leading chemical for developing therapeutic and/or prophylactic drugs for neurodegenerative disorders.     

Induction of apoptosis in HEp-2 cells by infection with herpes simplex virus type 2

Although herpes simplex virus type 1 (HSV-1) does not induce apoptosis in infected HEp-2 cells, herpes simplex virus type 2 (HSV-2) did induce apoptosis in a small but significant fraction of the same cells. Apoptosis was not observed in Vero or HeLa cells infected with HSV-2. In addition, HSV-2 infection in the presence of cycloheximide induced extensive apoptosis of HEp-2 or HeLa cells.     

Feasibility study for worldwide videotex interworking

Results are presented of a study of the feasibility realizing a real-time information retrieval service operating between different worldwide videotex systems by means of gateway facilities that use conversion of data syntax and processing of the videotex information structure. Two separate evaluations were carried out, both using response time as the performance criterion. One was for communication processes at both of two gateways, and the other was for data syntax conversion at the local host. Both approaches are considered as kernel functions in the gateway system. The results of each evaluation were favorable in the sense that response time for the total system using gateways compared favorably to the response time in direct videotex access over the packet-switched public data network     

N-Alkylation of chitin and some characteristics of the novel derivatives

Summary Introduction of simple alkyl groups at the C-2 nitrogen of chitin and some properties of the resulting N-alkyl-chitins have been examined. Chitosan was fully deacetylated and treated with three kinds of aldehydes, formaldehyde, acetaldehyde, and pentanal. The Schiff bases of chitosan, whose extents of substitution were dependent on the amount of aldehydes, were reduced with sodium cyanoborohydride to N-alkylated chitosans. The N-alkyl-chitosans were then transformed into the corresponding N-alkyl-chitins by acetylation with acetic anhydride followed by transesterification to remove partly formed O-acetyl groups. The resulting N-methyl-, ethyl-, and pentyl-chitins were amorphous and showed improved affinity for organic solvents. Received: 13 December 2001/Revised version: 11 January 2002/Accepted: 17 January 2002