High‐level extracellular production of penicillin acylase by genetic engineering of Escherichia coli

The extracellular production of penicillin acylase (PAC) in genetically engineered Escherichia coli by coexpression of the brp gene encoding bacteriocin release protein (BRP) and the pac gene was demonstrated. Cell physiology was affected while PAC was released into the medium, depending on the strategy for brp expression. The performance for the production and release of PAC was optimized by taking several culture parameters, including host, inducer (mitomycin C) concentration, and induction timing for brp expression, into consideration. The effect of PAC release on inclusion body formation was also investigated. It was observed that the amount of inclusion bodies was significantly affected by brp expression. A reason for the limitation of PAC production and a strategy for resolving this problem are proposed. © 2001 Society of Chemical Industry     

A study of liquefaction related damages on shield tunnels

Studies of liquefaction-related damages on underground structures are limited and sometimes controversial. Liquefaction potential analysis is essential in tunnel design in liquefiable soils. A Taipei Rapid Transit System (TRTS) tunnel site in Taipei County was selected to study the risk under liquefaction-related damage. The liquefaction risk index was applied for assessment of the overall liquefaction risks and liquefaction-induced settlement at the interest site. The anti-liquefaction measure for shield tunneling by using secondary injection grouting was discussed to eliminate the flow of liquefied soils and reduce the liquefaction-induced settlement.     

Storage temperature and packaging condition affect the total phenolic content and antioxidant activity of black soybeans and koji

In this study, powders of steamed black soybeans and the Aspergillus awamori‐fermented black soybeans (koji) were subjected to storage at 4 °C and 25 °C with or without deoxidant and desiccant for 120 days. It was found that total phenolic content and the antioxidant activity including the DPPH radicals scavenging effect, Fe²⁺‐chelating ability and reducing activity of the methanol extracts from black soybeans and koji decreased as the storage period was extended. Furthermore, storage temperature and packaging condition affected the antioxidant activity of the methanol extracts of black soybeans and koji. After 120‐day storage, extract from black soybeans holding at 4 °C with deoxidant and desiccant exhibited the highest residual of DPPH radicals scavenging effect, Fe²⁺‐chelating ability and reducing activity of 71.78%, 72.66% and 70.04%, respectively. Meanwhile, the highest residual of 77.78%, 81.71% and 85.05% respectively, was noted with extract from koji held at 25 °C with deoxidant and desiccant.     

Thermal degradation and flammability of P/Si polysilsesquioxane epoxy nanocomposites

A thermal stable epoxy nanocomposite prepared from the 4,4′‐diglycidylether bisphenol A (DGEBA) and the P/Si ladder‐like polysilsesquioxane (PSSQ). The activation energies of thermal degradation were calculated by Kissinger's and Ozawa's methods. The higher ladder‐like PSSQ content not only increase the oligomer content but also generate the steric hindrance. Which steric hindrance influence the epoxy/amine curing reaction of the modified epoxy system was more than the pristine DGEBA epoxy system. The P‐Si synergistic effect on the thermal stability of the nanocomposites was discussed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Enhancement of condominium management based on the effect of quality attributes on satisfaction improvement

Condominium management (CM) businesses rely on continuous improvements to service quality (SQ) to increase consumer satisfaction (CS) and thereby improve operations. Lacking knowledge of SQ and CS results in poor efficiency. To develop cost-effective strategies for improvements, the relationship between SQ and CS must be investigated. This work proposes novel procedures to explore the relationship between identified SQ attributes and CS in the CM business. First, we conduct exploratory factor analysis to cluster intrinsically similar attributes into three constructs and identify significant attributes for subsequent assessment. Furthermore, resident satisfaction scores (RSSs) are computed to assess the relative importance rate (RIR) of investigated attributes by applying an adapted multivariate method to regress the RSSs on the performance of SQ attributes. To facilitate the decision-making process, the service-quality model evolved from the integration of an improved Kano’s approach and importance-performance analysis (IPA) is utilized to develop a prioritized strategy for satisfaction improvements in the CM business.     

Cloning of the Major Capsid Protein (MCP) of Grouper Iridovirus of Taiwan (TGIV) and Preliminary Evaluation of a Recombinant MCP Vaccine against TGIV

Fish iridoviruses cause systemic diseases with high mortality in various species of wild and farm-raised fish, resulting in severe economic losses. In 1998, we isolated a new epizootic iridovirus in cultured grouper (Epinephelus sp.) in Taiwan, thus named as grouper iridovirus of Taiwan (TGIV). We report here the cloning of TGIV major capsid protein (MCP). Phylogenetic analysis of the iridoviral MCPs confirmed the classification of TGIV into the Megalocytivirus genus. Recombinant TGIV MCP and GIV MCP were then generated to produce polyclonal antibodies. Western blot analysis revealed that the two antisera were species-specific, indicating no common epitope shared by the MCPs of the two viruses. We further assayed the potency of a subunit vaccine containing recombinant TGIV MCP. The vaccine effectively protected grouper from TGIV infection. The result demonstrated that MCP is a suitable antigen for anti-TGIV vaccines.     

Effect of O2 concentration on performance of solid oxide fuel cells with V2O5 or Cu added (LaSr)(CoFe)O3-(Ce,Gd)O2−x cathode with and without NO

A solid oxide fuel cell unit is constructed with Ni-(Ce,Gd)O_2−x (GDC) as the anode, yttria-stabilized zirconia as the electrolyte, and V₂O₅ or Cu added (LaSr)(CoFe)O₃-GDC as the cathode. The effect of the O₂ concentration on the open circuit voltage (OCV) is studied and a mass-transfer limited OCV is observed. The power density with Cu addition can be much higher than that with V₂O₅ addition but the effect of the O₂ concentration with Cu addition is larger than that with V₂O₅ addition. Without the presence of NO, both the power density and the OCV decrease with decreasing O₂ concentration. The OCV variation can be substantial with the variation of the flow rate, the O₂ concentration and the NO concentration. The presence of CO₂ can increase the OCV while that of NO can decrease the OCV; however, a synergistic effect can occur on the OCV when NO is present at a very low O₂ concentration which results in a sudden drop of the OCV.     

Adolescent to emerging adulthood smoking trajectories: when do smoking trajectories diverge, and do they predict early adulthood nicotine dependence?

This study evaluated the adolescent tobacco-use trajectories that predict nicotine dependence in early adulthood and when these trajectories start to diverge. As part of a follow-up to a large prevention trial, the present study evaluated 1,017 individuals from early adolescence (age 12) to early adulthood (age 28). Participants were recruited from eight middle schools in Kansas City, Missouri. Students were entering 6th grade or 7th grade at baseline. Smoking was evaluated at baseline, 6 months, at annual follow-ups through high school, and every 18 months thereafter until age 28. The study goals were to determine (a) whether distinct weekly tobacco-use trajectories could be identified between early adolescence and emerging adulthood (ages 12-24); (b) when during development these trajectories diverged; and (c) which trajectories could predict nicotine dependence in early adulthood (ages 26-28). A four-trajectory mixed model (abstainers, low users, late stable users, and early stable users) demonstrated the best fit to the data. Membership in increasingly high-use trajectories placed participants at greater relative risk for becoming nicotine dependent than did membership in lower-use trajectories. General linear models showed greater weekly cigarette consumption for early stable users as early as the first wave of data collection (age 12) and significant differences among all other trajectories by age 15. The findings support the implementation of smoking prevention programs early in middle or junior high school and suggest that adolescents who are already smoking at least two cigarettes per week by age 12 may benefit from additional addiction prevention efforts.     

浅谈如何在工程量清单计价体系下签订固定总价合同

订立固定总价合同,要求投标方认可清单的工程量,投标方顺利地理解清单,并对清单工程量认可是签定总价合同的关键。文章围绕这个问题展开论述。