Protein engineering of alcohol dehydrogenases; effects of amino acid changes at positions 93 and 48 of yeast ADH1

By protein engineering we have investigated changes to two aminoacid residues (Trp93 and Ser48) in the substrate pocket of yeastalcohol dehydrogenase 1. Upon changing Thr48 to serine we producedan enzyme which has markedly greater activity towards aliphaticalcohols with chain length up to 8, together with a generalincrease in catalytic activity (V/K). Changes at position 93were less pronounced, with the Phe enzyme being more activethan the parent towards the range of alcohols but with the alanineenzyme showing very little difference from the wild-type. Enzymeswith the double changes at 48 and 93 showed increased activitytowards alcohols with 3–8 carbons but the increases werenot additive over the single changes. The enzymes with changesat the two positions would metabolize both stereoisomers of2-octanol whereas the parent ADH would attack only one of them.None of the engineered enzymes would attack cyclohexanol oraromatic alcohols. The results are in general agreement withthe prediction that reducing the size of amino acids in thesubstrate pocket would enhance the ability to oxidize alcoholslarger than ethanol.     

增加电极位置信息的电子耳蜗听觉仿真模型

为了改进以正弦信号合成的电子耳蜗听觉仿真模型在仿真电子耳蜗植入患者所感知的语音信息的缺陷,建立了增加电极位置信息的正弦信号合成的听觉仿真模型.通过大样本量的不同汉语语言材料的听觉仿真实验,其中包括按元音、辅音、数字、音调和单字词等5种汉语语言材料,研究了基于连续交叉采样算法的不同实验条件下电极位置对言语识别率的影响,得出了汉语元音和单字词对植入深度更加敏感的结论.为进一步将这一仿真模型应用到电子耳蜗研究上奠定了基础.     

Design of a new type of mine rescue relay cabin

This paper presents the design of an innovative mine emergency rescue relay cabin, and investigates a detailed comparison of existing shelter facilities, their function, service object, structures, size, and system components with the newly designed mine emergency rescue relay cabin. Air-tightness test indicated a test chamber relief rate of 26 Pa/min, which meets the design requirements. Furthermore,respirator replacement test showed an average time of 73.7 s to replace a respirator. The air cover air supply test indicated an air supply rate of 220 L/min, which is sufficient for the staff replacing the respirator in the emergency rescue relay cabin. The total air supply volume is 9680 L, which can be supplied via two compressed air cylinders of 40 L, pressurized to15 MPa.     

Competitive Cr3+ occupation in persistent phosphors toward tunable traps distribution for dynamic anti-counterfeiting

Red/near infrared (NIR) long persistent phosphors have received extensive attentions in biomedical, food inspection, iris recognition, biological imaging, etc. Herein, a new phosphor, Li₂ZnGe₃O₈:Cr³⁺, is reported with deep red persistent luminescence peaking at 708 nm. By adjusting the Cr³⁺ doping concentration, the competitive site occupation at [ZnO6] and [GeO6] polyhedral enables different traps behaviors including trap types, trap concentration and trap depth, which in turn leads to different afterglow duration time from 2 to 20 h. The persistent luminescence mechanisms originated from different trap models have been discussed, and it is found that they can cooperate or inhibit each other, enabling different luminescence depending on time. The dynamic anti-counterfeiting applications have been demonstrated, which provides a new way to rationally designing for multi-functional luminescent materials.     

日照苏家村遗址出土钱山漾文化陶鬶的产地研究

日照苏家村遗址位于鲁东南沿海地区,是大汶口文化晚期至龙山文化早中期一处重要的环濠聚落。该遗址新出土的钱山漾文化细长颈袋足鬶(M45:5)作为目前已知南方系陶鬶布最北的一件,揭示出公元前2300年前后中国南北方的区域文化交流。本文通过对苏家村出土钱山漾文化红陶鬶、其他龙山文化红陶鬶及部分苏家村黑陶的主、微量元素分析,结合主成分分析揭示了苏家村本地生产钱山漾文化红陶鬶的可能性,表明龙山文化早中期的制陶业的发展可能伴随着南方系制陶工匠的迁徙。     

Solid-solution hardening and softening by Fe additions to NiAl

Solid-solution hardening in the case of a ternary alloy addition to a B2 compound with the triple defect structure has been investigated. The fact that the ternary element may occupy either of two sublattices or may affect the concentration of other types of point defects present in the material makes this a very interesting problem to consider. Ni-rich (40 at% Al), stoichiometric (50 at% Al), and Al-rich (52 at% Al) alloys were doped with up to 12 at% Fe. Lattice parameter, bulk density and hardness measurements were performed on samples quenched from 1000 °C. It was found that solid-solution softening actually occurs in the Ni-rich alloys, while hardening was observed in the stoichiometric and Al-rich alloys. The vacancy concentration was determined from the experimental data, and the site occupancies of the Fe atoms were estimated from a thermodynamic model. Through careful consideration of all point defect concentrations the solid-solution hardening and softening behaviors could be effectively rationalized.     

Understanding the intentions of users to ‘stick’ to social networking sites: a case study in Taiwan

Social networking sites (SNSs) are the most popular social platforms for developing personal networks. They provide multiple interactive functions for users to create and use large social networks. To determine why people exhibit ‘stickiness’ to SNSs, this study uses the uses and gratifications theory as an underlying structure and builds the research model with factors of motivational needs and interactivity. Our results showed that social needs, information needs, human–message interaction, and human–human interaction are crucial factors that affect the ‘stickiness’ of users to SNSs. The implications of these findings are presented in this paper.     

活动断裂对新建集镇选址规划的影响——以乌东德水电站库区移民集镇选址为例

活动断裂附近地质条件复杂,在其附近进行新城镇选址时必须明确活动断裂对场地和建筑可能带来的不利影响。以金沙江乌东德水电站库区移民集镇选址为例,依照规范要求,综合地质调查、物探、勘探等手段,查明了元谋活动断裂的分布及特征;对其可能产生的震害类型及程度进行了分析;结合地质条件对规划场地工程建设的适宜性进行了分区;明确了活动断裂对场地和建筑物的影响,为合理设防、规避震害奠定了基础。可为类似新建城镇选址规划提供借鉴。      

Designing a Special Library's Intranet for an Engineering Audience

ABSTRACT

Designing a successful library Web site for an engineering audience means researching how engineers find and use information. It also requires the special librarian to conduct usability tests to determine what is and isn't working on the site. The special librarian is more than simply a librarian, he or she must be able to take the research and the test results and either build the Web site or make sure the site is built by a team. The librarian must be able to play several roles: researcher, tester, project leader, and Web manager. The more successful the librarian is at involving users in site design, the more used and usable the site will be. This article describes one librarian's experience with designing a special library Intranet. It also includes an extensive bibliography of related articles.     

HealthLinks: A ColdFusion Web Application

SUMMARY

Libraries are beginning to use Web applications as they grapple with sites of increasing complexity, and the move of more user services to the Web. This article reviews the basic concepts of a Web application, and outlines some of the features of the HealthLinks Web application and site http://healthlinks.washington.edu at the University of Washington Health Science Libraries, and the transition from a Java-based application to ColdFusion.