Structure and functional complementation of engineered fragments from yeast phosphoglycerate kinase

Previous studies have shown that, although the isolated structuraldomains of yeast phosphoglycerate kinase recover a quasi-nativestructure in vitro as well as in vivo, they do not reassociatenor generate a functional enzyme. The aim of this work was firstto study the folding of complementary fragments different fromstructural domains and second to determine the requirementsfor their reassociation and functional complementation. Themethod used for producing rigorously defined fragments consistsof the introduction of a unique cysteinyl residue in the proteinfollowed by a specific cleavage by 5'5'-dithiobis(2-nitrobenzoate)/potassiumcyanide at this residue. Two pairs of complementary fragmentswere thus obtained, 1–96/97–415 and 1–248/249–415.The structure and stabilities of the different fragments werestudied. The short fragments, i.e. 1–96 and 249–415were found to contain some secondary structure, but to havea low stability. Each large fragment has a high structural contentand a stability close to that of the corresponding domain. Incontrast to that observed with the isolated domains, a weakbut significant complementation was observed for the two pairsof fragments; the pair of fragments 1–248/249–415recovered 8% of the activity of the native enzyme upon complementation.An independent refolding of the complementary fragments beforereassociation decreased the yield of complementation for thepair of fragments 1–96/97–415, but did not affectthe complementation for the other pair (1–248/249–415).From the present data and previous work on the isolated domains,it appears that the correct folding of the isolated fragmentsis not a prerequisite for their complementation.     

Cognitive evaluation for conceptual design: cognitive role of a 3D sculpture tool in the design thinking process

ABSTRACT

This study focuses on the decisive role played by the digital design environment in the cognitive design process and design thinking. To analyse the cognitive role of digital design tools, we carried out a protocol analysis of conventional design sketching and a 3D sculpture tool. Cognitive evaluation was a differentiating factor when considering the contextual role of the 3D sculpture tool in subsequent evaluations, non-sequential evaluations for conversion, and passive approaches within the design process. Cognitive evaluation played the following roles: validation, extension, navigation, exploration, and confirmation. The navigation, exploration, and extension roles played by non-sequential evaluation were mainly related to inductive design thinking. Finally, the types of cognitive evaluation and their roles when using the 3D sculpture tool were different, according to the design thinking type. This study explored the multidimensional roles of cognitive evaluation using a 3D sculpture tool and its relationship with design thinking types.     

确保管道运输的泄漏检测技术

保证所有管道中石油从一端流向另一端不泄漏要比它的探测更加困难。比较图中的3个系统,可以看到这项技术在40多年来是如何逐步发展的。     

Energy- and Latency-Efficient Processing of Full-Text Searches on a Wireless Broadcast Stream

In wireless mobile computing environments, broadcasting is an effective and scalable technique to disseminate information to a massive number of clients, wherein the energy usage and latency are considered major concerns. This paper presents an indexing scheme for the energy- and latency-efficient processing of full-text searches over the wireless broadcast data stream. Although a lot of access methods and index structures have been proposed in the past for full-text searches, all of them are targeted for data in disk storage, not wireless broadcast channels. For full-text searches on a wireless broadcast stream, we firstly introduce a naive, inverted list-style indexing method, where inverted lists are placed in front of the data on the wireless channel. In order to reduce the latency overhead, we propose a two-level indexing method which adds another level of index structure to the basic inverted list-style index. In addition, we propose a replication strategy of the index list and index tree to further improve the latency performance. We analyze the performance of the proposed indexing scheme with respect to the latency and energy usage measures, and show the optimality of index replication. The correctness of the analysis is demonstrated through simulation experiments, and the effectiveness of the proposed scheme is shown by implementing a real wireless information delivery system.     

新型水库调度自动化系统

主要对具有可组态的、多阶层的新型水库调度自动化系统进行了分析， 并简要介绍国家电力调度中心水库调度自动化系统的部分应用情况。     

文蛤蛋白抗氧化活性肽的研究

利用正交实验研究了文蛤蛋白分别经木瓜蛋白酶、中性蛋白酶、酸性蛋白酶作用后酶解物对羟自由基和超氧自由基的清除作用,优化了水解条件,并对最佳清除率下的三种酶解物进行SephadexG50凝胶柱分离,测定酶解物中抗氧化活性肽的分子量分布。结果表明,三种酶酶解文蛤所得的酶解产物对自由基均具有清除作用,水解液中多肽的分子量主要集中在1000以下,分别占图谱面积的51.90%、61.7%和42.07%。     

污水污泥两相厌氧消化系统动力学特性研究

采用Chen—Hashimoto模型研究了不同进料基质浓度下,污泥中温两相厌氧消化小试工艺的动力学特性。根据两个投加不同来源剩余污泥的系统运行数据,表明基质Ⅱ中存在抑制物质。添加厨余垃圾的系统动力学参数μmax和K值都高于未添加的两个系统,这表明添加厨余垃圾提高了厌氧消化工艺的产气性能,污泥与有机固体废物的联合厌氧消化效率要高于污泥单独消化。根据Chen—Hashiraoto模型分别计算出小试系统的动力学参数值μmax和K,基质Ⅰ、Ⅱ和Ⅲ的μmax值分别为0．177、0．146、0．209d^-1,K值分别为0．239、0．178和0．265。     

高岭土干法有机改性及效果评价

本实验采用干法改性工艺,选用十二胺、十八胺、硬脂酸、硅油和铝钛复合偶联荆(OL-ATl618)五种不同的改性剂对云南临沧高岭土进行表面改性.对改性高岭土进行活化指数和有效活化指数测定,并对其进行红外光谱分析以确定最佳改性剂.最后选效果最好的改性高岭土作为橡胶填料进行力学性能检测.实验结果表明,对云南临沧高岭土进行表面有机改性.以十八胺为改性剂,加八量为1.2%.改性时间为30min改性高岭土的有效活化指数最高,改性效果最佳.有效活化指教越高,对橡胶的补强效果越好.     

生物质油精制的研究进展

综述了近20年里生物质油精帛的研究进展,着重介绍了催化加氢和催化裂化两种生物质油精制方法,简述了这两种方法的动力学和要,提出了生物质油精制的发展方向。