Cloning and characterization of the Pichia pastoris PRC1 gene encoding carboxypeptidase Y

We purified a 58 kDa serine protease from culture-supernatant of Pichia pastoris and found that the NH₂-terminal amino acid sequence of this protease is closely homologous to that of mature protein of Saccharomyces cerevisiae carboxypeptidase Y (CPY), which is encoded by the PRC1 gene. Using the S. cerevisiae PRC1 gene as a hybridization probe, a cross-hybridizing fragment of P. pastoris genomic DNA was identified and the gene, PRC1, encoding CPY, was cloned. The open reading frame of the P. pastoris PRC1 gene consists of 1569 bp encoding a protein of 523 amino acids. The molecular mass of the protein is calculated to be 59·44 kDa without sugar chains. The protein comprises 20 amino acids of pre (signal)-peptide, 87 amino acids of pro-peptide and 416 amino acids of mature peptide, and has four N-glycosylation sites. The NH₂-terminal amino acid sequence of mature peptide is completely identical with that of the protease purified from the culture-supernatant. There is 61% identity between the amino acid sequences of P. pastoris Prc1p and S. cerevisiae Prc1p. Chromosomal disruption of the PRC1 gene resulted in the loss of CPY activity. Over-expression of the PRC1 gene under regulation of the P. pastoris AOX1 promoter resulted in accumulation of a large amount of active CPY in the intracellular fraction, and secretion of a slightly larger molecule that is thought to be pro-CPY. The nucleotide sequence data reported in this paper will appear in the EMBL Nucleotide Sequence Databases under the Accession Number X87987.     

Upper bound estimate of scaled reinforced soil retaining walls

A kinematic approach based on the framework of limit analysis is applied for stability analysis of model reinforced vertical and sloping walls with cohesive backfill that were brought to failure under self-weight in a geotechnical centrifuge. A rotational failure mechanism is used to compute critical heights of the unreinforced and reinforced models; and the Constrained Simplex method is employed in the optimization scheme. The prototype equivalent heights predicted by the analyses are within the distress range; i.e., development of tension crack and collapse of the retaining walls occurred during centrifuge tests.     

Comparative effects of safflower oil and perilla oil on serum and hepatic lipid levels, fatty acid compositions of serum and hepatic phospholipids, and hepatic mRNA expressions of 3-hydroxy-3-methylglutaryl CoA reductase, LDL receptor, and cholesterol 7alpha-hydroxylase in young and adult rats

Male Wistar rats, 4 and 33 weeks of age, were fed the diets containing safflower oil (SO-diet, 77.3% linoleic acid) or perilla oil (PO-diet, 58.4% -linolenic acid) for 7 days. Serum total cholesterol was lower on the PO-diet in both ages. On the other hand, hepatic cholesterol and phospholipids were significantly higher in the PO group than in the SO group of the adult rats. The PO group showed significantly lower 20:4 n-6 but higher 18:2 n-6 in hepatic phosphatidylcholine compared with the SO group in both ages. Hepatic 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase mRNA was significantly lower on the PO-diet than on the SO-diet irrespective of age. The present results show that -linolenic acid has a higher hypocholesterolemic ability than linoleic acid in rats irrespective of age and these fatty acids behaved differently in affecting hepatic mRNA expressions of HMG-CoA reductase, LDL receptor, and cholesterol 7-hydroxylase.     

The effect of surfactant in the absorptive and generative processes

This study investigates the effect of additives such as normal octyl alcohol into lithium bromide-water (LiBr/H₂O) solutions in the absorption and generation processes of absorption refrigerating machines. The experimental results confirmed the positive effect of additive use in the absorber. Little is known, however, on the effect of additives on generator performance. In this study, the authors carried out experiments to investigate the possible positive or negative effects of additive, which enhances the absorption process, on the generator behavior. The results showed heat transfer at the generator improved as pressure increased and concentration decreased; the boiling heat transfer coefficient was shown to be more strongly influenced by concentration than by pressure. The boiling curves showed that the heat transfer of solution in the generator was not significantly affected by the addition of surfactant. The result of this study showed that the surfactant in absorption heater/chiller made enhanced absorption effect in the absorber but it didn't give any influence in the generator. Therefore the additive was devoted to helping high performance in the absorption system.     

高密度烧结金属齿轮的承载能力(英文)

This paper describes a study on the load bearing capacity of newly developed high density sintered metal gears with surface - densification. High density sintered metal gears were hobbed, and then surface - rolled. These gears were case - carburized after surface - rolling. The effect of surface - rolling on the surface property was examined by measuring porosity, and hardness near surfaces of rolled gears. Running tests for these gears were performed. A failure mode and load bearing capacity of high density sintered metal gears and the effects of surface - rolling on the load bearing capacity of sintered metal gears were determined, and the results were compared with those of carburized wrought steel gears and conventional sintered metal gears. The experimental results show that the load bearing capacity of a newly developed high density sintered metal gear with surface - densification is higher than that of a carburized wrought steel gear.     

Theoretical analysis of the optimal configuration of co-generation systems and competitiveness of heating/cooling technologies

This study aims at exploiting optimal configurations of technologies combined with co-generation theoretically based on a linear optimization model. With the objective function defining primary energy consumption to be minimized, optimal solutions are derived analytically. They describe the technological configurations as well as associated conditions depending on their final energy demand. An interesting finding is that the essential parameters to determine the configurations are heat, cooling and steam demands normalized by power demand. The optimal solutions are also applied to investigate the competitiveness of co-generation related technologies. The optimal solutions yield critical conditions theoretically, which is useful to understand the priority of the technologies. A sensitivity analysis numerically indicates that absorption chillers can be superior to compression chillers even though the former has lower COP than the latter. Actual data of various types of co-generation are also examined to show the practical competitiveness.     

Experimental investigation on test methods for mode II interlaminar fracture testing of carbon fiber reinforced composites

In this paper, experimental investigation on the test methods for mode II interlaminar fracture testing of carbon fiber reinforced composites are carried out. Mode II interlaminar fracture testing of unidirectional composite of carbon fiber reinforced epoxy (T800/#3631) are conducted using four kinds of test methods, namely end notched flexure (ENF) test, end loaded split (ELS) test, four-point bend end notched flexure (4ENF) test, and over notched flexure (ONF) test. An analytical model based on a point-friction assumption and classical beam theory is proposed to evaluate the effect of friction between crack faces on the mode II interlaminar fracture toughness in the 4ENF and ONF tests. The analytical model is validated by the comparison of analytical results with previous ones obtained from finite element analysis. Experimental results show that the ENF test gives reliable initiation value of fracture toughness with a small scatter and that the average value of fracture toughness obtained from 4ENF test is about 2% higher than that obtained from the ENF test. The effect of friction in the 4ENF test is much lower than that in the ONF test in which the effect of friction increases with the crack growing. It is concluded that the 4ENF test method is an effective test method for the experimental evaluation of mode II propagation interlaminar fracture toughness of carbon fiber reinforced composites.     

Study of flow fractionation characteristics of magnetic chromatography utilizing high-temperature superconducting bulk magnet

We present numerical simulation of separating magnetic particles with different magnetic susceptibilities by magnetic chromatography using a high-temperature superconducting bulk magnet. The transient transport is numerically simulated for two kinds of particles having different magnetic susceptibilities. The time evolutions were calculated for the particle concentration in the narrow channel of the spiral arrangement placed in the magnetic field. The field is produced by the highly magnetized high-temperature superconducting bulk magnet. The numerical results show the flow velocity difference of the particle transport corresponding to the difference in the magnetic susceptibility, as well as the possible separation of paramagnetic particles of 20 nm diameter.     

一种带智能电子控制系统的新型自动变速器的丰田“ECT-i”

丰田已经开发了一种新型自动变速器名为A341E。这种变速箱采用一种极好的发动机和变速器一体化的智能控制系统叫做“ECT－i”和高性能的“超流”（SuperFlow）变矩器。这种控制系统换挡时可以综合控制发动机转矩和离合器液压,在变速器整个寿命期期间它可确保换档平稳性没有任何变化。“超流”变矩器采用计算机仿真通过内流分析经几何修正优化使它成为世界最高效率的一种变矩器,采用这样由于石油危机,自动变速器的技术开发燃油经济性已成为主要目标,着重于提高包括发动机的整个动力装置的效率。4档自动变速器开发和锁止离合器和它的电子控制系统已经进入实际使用阶段（1）、（2）、（3）,为了进一步改善车辆的驾驶和动力性能目前正努力增加变速器档数。司机对车辆性能的要求越来越高,要求自动变速器高的换档不仅是燃油经济性和动力性能而且还要求好的换档质量,降低噪音等等。所以对于随着变速器档位要求增加操纵许多齿轮档数,故平稳性和平静性包括质量控制是大多数自动变速器开发的主要目标。在这样的情况下,丰田已开发了一种新的自动变速器称为A34AE。这种变速器采用极好的发动机和变速器综合的智能控制系统和一个高性能“超流”变矩器。具有这样的系统,该系统自动变速器可实现十分平稳换档而整个装置寿命没有任何改变。本文将讨论该设计目标,结构、控制和其对A341E变速器的效果。