充分发挥行业协会作用搞好教育培训工作

中国电力企业联合会(简称中电联)是经国务院批准成立的全国电力行业企、事业单位的联合组织,主要任务是为全国电力企、事业单位提供服务并协助政府加强对电力工作的行业管理.……     

利用动态特性测量值的结构损伤检测方法的比较研究

对目前关于结构损伤检测的基本方法进行了回顾,详细地介绍了现有几种有效的基于结构动态特性测量值的损伤检测方法(包括传统的敏感性分析法、神经网络法和遗传算法)的基本步骤,讨论了这些方法在工程运用中存在的一些实际问题,如不完整的测量值、方法的鲁棒性、损伤检测的计算效率和收敛性等.最后,通过对实际五层钢框架结构的层间刚度识别说明了这几种主要方法的优缺点,提出了今后该领域的研究方向.     

用隔震技术提高已有建筑的抗震能力

以土耳其的抗震加固工程为背景,介绍了通过在已有建筑物中设置橡胶隔震支座来提高建筑物抗震性能的抗震加固新方法.这种方法能在不影响建筑物正常使用、不损伤建筑物装修的情况下完成施工,达到提高建筑物抗震能力的目的.     

节水灌溉的对策

根据佳木斯市郊区灌溉现状、工程情况,分析了灌区节水灌溉存在的问题.从实际出发,因地制宜地提出了相应的对策.     

Selective and Brain‐Permeable Polo‐like Kinase‐2 (Plk‐2) Inhibitors That Reduce α‐Synuclein Phosphorylation in Rat Brain

Polo‐like kinase‐2 (Plk‐2) has been implicated as the dominant kinase involved in the phosphorylation of α‐synuclein in Lewy bodies, which are one of the hallmarks of Parkinson’s disease neuropathology. Potent, selective, brain‐penetrant inhibitors of Plk‐2 were obtained from a structure‐guided drug discovery approach driven by the first reported Plk‐2–inhibitor complexes. The best of these compounds showed excellent isoform and kinome‐wide selectivity, with physicochemical properties sufficient to interrogate the role of Plk‐2 inhibition in vivo. One such compound significantly decreased phosphorylation of α‐synuclein in rat brain upon oral administration and represents a useful probe for future studies of this therapeutic avenue toward the potential treatment of Parkinson’s disease.     

Measuring the effects of laboratory automation: The power of empirically derived models

Laboratory data systems are automated for a variety of scientific and management reasons. A key part to maintaining these systems is to regularly assess the impact that automation has had on the laboratory and the organization as a whole. Smith Kline Beecham R&D is using a number of different types of measurement, as well as a number of different tools, for measuring how automated laboratory systems are affecting the workflow and information flow in the laboratory. This targeted programme of metrics has increased management confidence in laboratory automation efforts, helped anticipate data processing bottlenecks, and highlighted end-user support needs.     

Inhibitory Effect of Conjugated α-Linolenic Acid from Bifidobacteria of Intestinal Origin on SW480 Cancer Cells

In this study, we assessed the ability of six strains of bifidobacteria (previously shown by us to possess the ability to convert linoleic acid to c9, t11-conjugated linoleic acid (CLA) to grow in the presence of α-linolenic acid and to generate conjugated isomers of the fatty acid substrate during fermentation for 42 h. The six strains of bifidobacteria were grown in modified MRS (mMRS) containing α-linolenic acid for 42 h at 37 °C, after which the fatty acid composition of the growth medium was assessed by gas liquid chromatography (GLC). Indeed, following fermentation of one of the strains, namely Bifidobacterium breve NCIMB 702258, in the presence of 0.41 mg/ml α-linolenic acid, 79.1% was converted to the conjugated isomer, C18:3 c9, t11, c15 conjugated α-linolenic acid (CALA). To examine the inhibitory effect of the fermented oils produced, SW480 colon cancer cells were cultured in the presence of the extracted fermented oil (10–50 μg/ml) for 5 days. The data indicate an inhibitory effect on cell growth (p ≤ 0.001) of CALA, with cell numbers reduced by 85% at a concentration of 180 μM, compared with a reduction of only 50% with α-linolenic acid (p ≤ 0.01).     

Dolichodial: A New Aphid Sex Pheromone Component?

The sex pheromones of many aphid species from the subfamily Aphididae comprise a mixture of the iridoids (cyclopentanoids) (1R,4aS,7S,7aR)-nepetalactol and (4aS,7S,7aR)-nepetalactone. In this paper, we investigate whether other chemicals, in addition to nepetalactol and nepetalactone, are released from Dysaphis plantaginea (rosy apple aphid) oviparae as part of their sex pheromone. Four compounds present in an air entrainment sample collected from D. plantaginea oviparae feeding on apple (Malus silvestris c.v. Braburn) elicited electrophysiological responses from male D. plantaginea. Active peaks were tentatively identified by gas chromatography (GC) coupled with mass spectrometry, with identification confirmed by peak enhancement with authentic compounds on GC columns of different polarities. The electroantennography-active chemicals were (1R,4aS,7S,7aR)-nepetalactol, (4aS,7S,7aR)-nepetalactone, (1S,2R,3S)-dolichodial, and phenylacetonitrile. (1S,2R,3S)-Dolichodial elicited a behavioral response from male D. plantaginea and naïve-mated female parasitoids, Aphidius ervi. This is the first report of electrophysiological and behavioral responses from any aphid morph to (1S,2R,3S)-dolichodial. Whether or not (1S,2R,3S)-dolichodial is a third component of the aphid sex pheromone is discussed.     

In vitro generation and stability of the lactokinin beta-lactoglobulin fragment (142-148)

The objectives of this study were to investigate the generation of beta-lactoglobulin fragment (142-148) (beta-LG f(142-148) during the hydrolysis of whey proteins, and the in vitro stability of this fragment upon incubation with gastrointestinal and serum proteinases and peptidases. An enzyme immunoassay (EIA) protocol was developed for the quantification of beta-LG f(142-148) in whey protein hydrolysates and in human blood serum. The minimum detection limit was 3 ng/mL. The level of the peptide in whey protein hydrolysates was influenced by the degree of hydrolysis (DH). As expected, highest levels of this peptide were found in hydrolysates generated with trypsin. Sequential incubation of hydrolysates at different DH values with pepsin and Corolase PP, to simulate gastrointestinal digestion, generally resulted in the degradation of beta-LG f(142-148) as determined by EIA. Reversed-phase HPLC and angiotensin-I-converting enzyme (ACE) activity assays demonstrated that synthetic beta-LG f(142-148) was rapidly degraded upon incubation with human serum. Furthermore, beta-LG f(142-148) could not be detected by EIA in the sera of 2 human volunteers following its oral ingestion or in sera from these volunteers subsequently spiked with beta-LG f(142-148). These in vitro results indicate that beta-LG f(142-148) is probably not sufficiently stable to gastrointestinal and serum proteinases and peptidases to act as an hypotensive agent in humans following oral ingestion. The in vitro methodology described herein has general application in evaluating the hypotensive potential of food protein-derived ACE inhibitory peptides.     

Methylmercury in mosquitoes related to atmospheric mercury deposition and contamination

A connection between loadings of inorganic Hg, especially from the atmosphere, and accumulation of methylmercury (MeHg) in aquatic biota has not been firmly established. Mosquitoes (Diptera: Culicidae) may be a useful indictor of Hg contamination or MeHg accumulation in aquatic ecosystems because they have aquatic life stages, and their ubiquitous distribution permits sampling across wide ranges of climate, biological productivity, and atmospheric Hg deposition. We examined MeHg in adult mosquitoes from subtropical (Florida), maritime (California), continental (Michigan), and arctic (Alaska) regions of North America that span a range in wet atmospheric Hg deposition (1.5-15 microg m(-2) y(-1)). More than 90% of the Hg in mosquitoes was MeHg, and concentrations varied among locations. Levels of MeHg differed among mosquito species at six sites in northwest Florida (Ochlerotatus atlanticus < Culex nigripalpus < Anopheles crucians); this may be related to differences in biogeochemical characteristics of the aquatic habitat that affect dietary accumulation of MeHg during the larval stage. Mosquito MeHg was related positively to wet atmospheric Hg deposition among locations where atmospheric deposition is the principal source of Hg, and it was greatly enhanced in Hg-polluted environs near the Sulphur Bank Mine in Lake County, California. These results suggest that MeHg in mosquitoes may be a useful and sensitive indicator of Hg loadings to aquatic systems, including that derived from atmospheric deposition.