Acylamino acid-releasing enzyme from the thermophilic archaeon Pyrococcus horikoshii

When the genome of the thermophilic archaeon Pyrococcus horikoshii was sequenced, a gene homologous to the mammalian gene for an acylamino acid-releasing enzyme (EC 3.4.19.1) was found in which the enzyme's proposed active residues were conserved. The P. horikoshii gene comprised an open reading frame of 1,896 base pairs with an ATG initiation codon and a TAG termination codon, encoding a 72,390-Da protein of 632 amino acid residues. This gene was overexpressed in Escherichia coli with the pET vector system, and the resulting enzyme showed the anticipated amino-terminal sequence and high hydrolytic activity for acylpeptides. This enzyme was concluded to be the first acylamino acid-releasing enzyme from an organism other than a eukaryotic cell. The existence of the enzyme in archaea suggests that the mechanisms of protein degradation or initiation of protein synthesis or both in archaea may be similar to those in eukaryotes. The enzyme was stable at 90 degreesC, with its optimum temperature over 90 degreesC. The specific activity of the enzyme increased 7-14-fold with heat treatment, suggesting the modification of the enzyme's structure for optimal hydrolytic activity by heating. This enzyme is expected to be useful for the removal of Nalpha-acylated residues in short peptide sequence analysis at high temperatures.     

Acquired laryngomalacia as a cause of airway obstruction immediately after unilateral mouth floor surgery

We report a case of acquired laryngomalacia in which airway obstruction due to prolapse of the epiglottis during inspiration was observed immediately after a unilateral mouth floor resection. Suggested causes are resection of unilateral elevator muscles of the hyoid bone, epiglottic oedema and transient loss of pharyngeal motor control due to surgical intervention and high-dose radiation.     

Helicobacter pylori infection enhances N-methyl-N-nitrosourea-induced stomach carcinogenesis in the Mongolian gerbil

No previous report has demonstrated the relationship between Helicobacter pylori (HP) infection and gastric carcinogenesis in an experimental animal model. A total of 170 male Mongolian gerbils (MGs) were divided into nine groups (18 < or = n < or = 20 for each group). MGs of four groups were inoculated with HP before or after continuous N-methyl-N-nitrosourea (MNU) administration via the drinking water. Both intestinal-type and diffuse-type adenocarcinomas, including signet ring-cell carcinomas, were found at 40 weeks after the study commenced, but only in the HP inoculation groups with MNU exposure and not in the MNU alone or HP inoculation alone control groups. The present findings demonstrate that HP infection increases the incidence of MNU-induced adenocarcinoma of the glandular stomach in MGs.     

Structural Degradation of Tobermorite during Vibratory Milling

Mechanochemistry of hydrothermally prepared Al-free and Al-substituted 1.1 nm tobermorite was studied using ²⁹Si NMR, XRD, and TGA-DTA. Tobermorite has a double-chain structure and Al/Si substitution occurs preferentially at bridging tetrahedra. By using the vibration mill, both tobermorites were observed to decompose as a function of milling time to form amorphous C-S-H-like phases. The decomposition rate was higher for the Al-substituted tobermorite. The decomposition process occurs mainly at the bridge portion of the silicate double chain. In the Al-substituted tobermorite, the breakage seems to occur preferentially at the points where Al has replaced Si. On heating the amorphous C-S-H-like phase, wollastonite is formed. However, no decrease was observed at the wollastonite formation temperature.     

自组装Cu-Fe基复合材料的设计与开发

The Cu-Fe base alloys with liquid immiscible were prepared by gas atomization technique and conventional solidification process, the self-assemble composite microstructures in powders and bulk materials can be obtained under gravity conditions, respectively, and the minor liquid phase always forms the center of composite microstructure. It is shown that the formation of the core-type macroscopic morphology is strongly connected with the existence of a stable miscibility gap of the liquid phase in the Cu-Fe base alloys. This result can be explained by a mechanism that the minor droplets as the second phase are forced to move into the thermal center due to Marangoni motion, which is caused by the temperature dependence of interracial energy between two liquid phases.     

Atherosclerosis and plasma and liver lipids in nine inbred strains of mice

Nine inbred strains of mice, which are progenitors of recombinant inbred sets, were evaluated for aortic lesion formation and plasma and liver lipid levels. This survey was done to determine if a semi-synthetic high-fat diet could elicit the same extent of diet-induced atherosclerosis as that observed in mice fed a natural ingredient highfat diet and to discover strain-specific plasma and liver lipid variants for future genetic characterization. Evaluation of aortic lesions after 18 wk of diet consumption showed that strains C57BL/6J, C57L/J, SWR/J and SM/J were susceptible to atherosclerosis and that A/J, AKR/J, C3H/HeJ, DBA/2J and SJL/J were relatively resistant. High-density lipoprotein cholesterol (HDL-C) levels were negatively correlated to lesion formation. Susceptible strains had decreased HDL-C levels when switched from chow to the semi-synthetic high-fat, high cholesterol diet, whereas resistant strains either showed no change or a slight increase in HDL-C levels. The exception to this pattern was found in SM mice, which were susceptible to aortic lesion formation but maintained the same HDL-C level on both chow and high-fat diets. HDL size differed among the strains, and levels of plasma apolipoprotein A-I and A-II correlated with HDL-C levels. Liver damage was not correlated to HDL-C levels or to susceptibility to atherosclerosis. Mice from strain A, which are resistant to atherosclerosis, had evidence of liver damage as observed by elevated levels of plasma alanine aminotransferase activity, by liver histology, by increased liver weight and by exceptionally high hepatic cholesterol content. For all strains, the levels of liver cholesterol and triglycerides were inversely correlated with each other; phospholipids did not vary greatly among strains. No remarkable differences in hepatic fatty acid profile were noted among the strains fed the atherogenic diet, but the fatty acid profile did differ considerably from that found in the diet itself.     

A numerical study of wave propagation and run-up in water channels

It is important to understand how water waves propagate through water channels in order to reduce inundation damages induced by surges and/or tsunami run-up. For this purpose, a two-dimensional numerical model is developed based on Nonlinear Shallow Water Equations. In order to appropriately describe the strongly nonlinear hydrodynamics, a high-order TVD scheme is implemented. Model capabilities are confirmed through comparison with existing analytical studies including the dam-break problems, run-up and back-wash on a sloping bathymetry. The model is then applied to the study on the inundation of bore propagating in a channel of parabolic cross-section from a side breach.

     

A Control Strategy for a Chemical Heat Pump Dryer

This article presents results of an experimental investigation on the controllability of hot air production using a pair of chemical heat pumps (CHP). The objective of this study is to determine how a CHP-assisted batch dryer can be operated effectively. The CHP uses the well-known CaO/H₂O/Ca(OH)₂ hydration/dehydration reaction, which is reversible. The hot air temperature can be controlled by adjusting the reactor temperature, and pressure, as well as thermal power supplied to it. It is shown that hot air can be produced in both the heat storage and heat release steps of the CHP.     

Co41Ni33-xAl26Cux的马氏体相变和磁性转变

Co-Ni-Al合金具有良好的加工性能，是很有前途的铁磁性形状记忆合金，本文通过金相显微分析、DSC、VSM方法，研究了Cu含量X对Co41Ni33-xA126Cu。合金马氏体相变和Curie点影响。结果发现在x≤5％范围内，C04lNim33-xAl26Cux合金马氏体相变温度与x的关系成直线变化，马氏体相变温度随x增加而迅速降低，x每增加1％，马氏体相变温度降低约44K；其Curie点随x增加而缓慢下降，x每增加1％，Curie点约降低3．6K。与L10马氏体结构的Co4lNi33-xA126Cux（x=0，3，5）合金相比，具有B2结构的Co41Ni25A126Cu8合金易磁化，并且饱和磁化强度低。     

Compensation of power fluctuations of wind power generation by means of biomass gas turbine generator and flywheel energy storage equipment

Power generation using natural energy contains electric power fluctuations. Therefore, in order to put such power generation systems to practical use, compensation for system power fluctuations is needed. In this paper, we propose a power compensation method using a biomass gas turbine generator and flywheel energy storage equipment. The gas turbine generator is used for compensation of low‐frequency power fluctuations in order to decrease the required flywheel capacity. The usefulness of the proposed system is confirmed by experiments using a test plant. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 170(3): 1–8, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20896