4种植物提取物对马鲛鱼保鲜效果研究

目的探索不同植物提取物对马鲛鱼的保鲜效果,为控制水产品质量提供技术依据。方法将马鲛鱼切块,经不同浓度的龙须菜寡糖(gracilaria lemaneiformis oligosaccharide,GLO)、大蒜提取物(garlic extract,GE)、迷迭香提取物(rosemary extract,RE)和生姜提取物(ginger root extract,GRE)浸泡30min,于4℃条件下贮藏,以菌落总数、生物胺、pH值、挥发性盐基氮(total volatile basic nitrogen,TVB-N)、K值等指标评价其新鲜度。结果 GLO、GE、RE和GRE处理可延缓马鲛鱼中腐败微生物生长,有效控制各指标值的变化情况,使马鲛鱼块货架期延长1~2d,进而初步明确了GLO、GE、RE和GRE处理马鲛鱼块的合适浓度依次为0.5%~1.0%、1.0%~1.5%、0.03%~0.06%、1.0%~1.5%。结论采用不同浓度的4种植物提取物可延长马鲛鱼的货架期。     

小龙虾微冻贮藏过程中特定腐败菌的分离鉴定及致腐产胺能力分析

目的 探究小龙虾微冻贮藏过程中特定腐败菌(specific spoilage organisms,SSOs)种类及其致腐产胺能力。方法 本研究利用选择性培养基从微冻至腐败小龙虾中分离、纯化优势腐败菌,通过16Sr DNA技术结合细菌生化鉴定法进行鉴定;将鉴定出的SSOs接种至无菌虾肉中,通过监测pH、挥发性盐基氮(total volatile basic nitrogen,TVB-N)、菌落总数等指标的变化,计算腐败代谢产物产量因子(YTVB-N/CFU)以评价各SSOs的致腐能力,并比较各SSOs接种组的产生物胺能力。结果 小龙虾微冻过程中的SSOs为荧光假单胞菌(Pseudomonas fluorescens)、腐败希瓦氏菌(Shewanella putrefaciens)、温和气单胞菌(Aeromonas sobria)和蜂房哈夫尼亚菌(Hafnia alvei);在贮藏15 d后, P. fluorescens、S. putrefaciens、A. sobria和H. alvei接种组TVB-N含量分别为205.88、54.01、60.60、24.24 mg/100 g,菌落总...     

Ecologies of Excess: An Excerpt from a 22nd-Century Architecture History Class

Written from the vantage point of the beginning of the 22nd century, Eva Franch i Gilabert looks back at the preceding century. Modernism and then sustainability have been surpassed by the Ecologies of Excess movement. Rather than seeking remediation for the natural environment and existing conditions, the excessive has become a foundational ground for design and sociopolitical change. Depicted projects are developed by Franch i Gilabert and the Ecologies of Excess research unit team at Rice University in Houston. Copyright © 2010 John Wiley & Sons, Ltd.     

离子交换去除饮用水中有机物的研究进展

近年来国外去除饮用水中有机物的方法有混凝澄清、活性炭吸附、膜分离以及离子交换法等,其中离子交换法可有效地去除饮用水常规处理产生的消毒副产物--低分子有机物.进而从离子交换树脂的本身特征、水质特征和有机化合物特征3方面详细讨论了离子交换去除饮用水中有机物的影响因素.     

Alternative DNA amplification methods to PCR and their application in GMO detection: a review

Nucleic acids, especially DNA, are targets of qualitative and quantitative diagnostics for genetically modified organisms (GMO) in seeds, food- and feedstuff. The amplification of the nucleic acid is an essential step for further analyses of the target sequence. The PCR has been the method of choice for DNA amplification in most laboratories, and its real-time version (qPCR) also enables quantitative analysis of target contents. Despite its numerous advantages, PCR technology has some limitations such as the lack of true multiplexing properties. To alleviate the drawbacks linked to PCR technology, alternative nucleic acid amplification methods with promising characteristics are being developed fast. These methods, their advantages, and the inconveniences, which are not yet resolved are summarized in the paper. Special focus is given to the possibilities of using these alternative methods for GMO detection in future, when expansion of GMOs both in diversity and frequencies will make current GMO detection systems difficult to operate.     

Estimated environmental loads of alpha-amylase from transgenic high-amylase maize

Environmental exposure of plants bioengineered to improve efficiencies of biofuel production is an important consideration for their adoption. High-amylase maize genetically engineered to produce thermostable alpha-amylase in seed endosperm is currently in development, and its successful adoption will entail >1000 km² of annual production in the USA. Environmental exposure of thermostable amylase will occur in production fields from preharvest and harvest dropped grain, with minor additional contributions from stover and root biomass. Mass loadings of thermostable alpha-amylase are projected to be 16 kg km⁻² and represent a potential source of increased alpha-amylase activity in receiving soils. An understanding of the degradation, persistence, accumulation, and activity of thermostable alpha-amylase introduced from transgenic high-amylase maize will be necessary in order to effectively manage transgenic crop systems intended or biofeedstock production.     

Differences between conventional and glyphosate tolerant soybeans and moisture effect in their discrimination by near infrared spectroscopy

Previous studies showed that Near Infrared Spectroscopy (NIRS) could distinguish between Roundup Ready® (RR) and conventional soybeans at the bulk and single seed sample level, but it was not clear which compounds drove the classification. In this research the varieties used did not show significant differences in major compounds between RR and conventional beans, but moisture content had a big impact on classification accuracies. Four of the five RR samples had slightly higher moistures and had a higher water uptake than their conventional counterparts. This could be linked with differences in their hulls, being either compositional or morphological. Because water absorption occurs in the same region as main compounds in hulls (mainly carbohydrates) and water causes physical changes from swelling, variations in moisture cause a complex interaction resulting in a large impact on discrimination accuracies.     

西南地区晚古生代深水生物相初探

西南地区晚古生代时位于华南陆板块的南部被动大陆边缘及陆内。自早泥盆世中晚期开始发生裂陷运动，在滇东、黔南和广西地区发生沿北西向为主，北东向为次的拉张裂陷沉降，最终形成由狭长的台问海槽和弧立碳酸盐台地相间排列的古地貌格局。由于浊流的发育、洋流作用，使深水海槽内海水局部混和充氧，各海槽内海水不完全停滞，不同于黑海式全封闭的阻隔式盆地。不同深度的海槽内具有不同的古生物组合，从浅到深，可归入充氧生物相，充氧──贫氧生物相，贫氧──厌氧生物相及厌氧生物相．     

Investigation of static transmission expansion planning using the symbiotic organisms search algorithm

Transmission expansion planning (TEP) has become a complex problem in restructured electricity markets. This article presents the symbiotic organisms search (SOS) algorithm, a novel metaheuristic optimization technique for solving TEP problems in power systems. The SOS algorithm is inspired by the interactions among organisms in an ecosystem. The TEP problem is formulated here as an optimization problem to determine the cost-effective expansion planning of electrical power systems. Several constraints, such as power flow of the lines, right-of-way validity and maximum line addition, are taken into consideration. First, the SOS algorithm is tested with several benchmark functions. Then, it is applied on three standard power system networks (IEEE 24-bus system, Brazilian 46-bus system and Brazilian 87-bus system) in a TEP study to demonstrate the optimization capability of the proposed SOS algorithm. The results are compared with those produced by other state-of-the-art algorithms.