莠去津的生态毒理学及其环境行为学研究进展

莠去津是世界范围内广泛使用的除草剂,在曾经使用莠去津的地区的水体中均检测到莠去津的残留,由于莠去津属于内分泌干扰物,长期暴露在该有机污染物的环境中,势必对各种生物产生不良影响。介绍了莠去津的生态毒理学研究进展及其环境行为研究的内容和热点,着重评述了莠去津对哺乳动物的各种毒性、在土壤中的吸附机制和迁移以及治理措施。     

Dynamics stability in wireless sensor networks active defense model

Wireless sensor networks, which are widely used in military, industrial and transportation fields, are vulnerable to various kinds of attacks, since they are mostly deployed in a relatively open environment. Based on the evolutionary game theory, this paper proposes a proactive defense model for wireless sensor networks, in which we emphasize that the node has a limited ability to learn the evolution of rationality from different attack strategies of the attacker, and can dynamically adjust their strategies to achieve the most effective defense. Following this approach, the cost (e.g., energy consumption and wastage of machinery) has been greatly saved and the life cycle of the nodes has been extended as well. By employing the proposed model, the whole wireless sensor network can be implemented in an effective way.     

RFID技术在国防工程安全管理系统中的应用

结合国防工程安全管理的现状和建设信息化部队的要求,考虑到现有的安全管理模式对人员和装备的精确化管理程度低和实时性差的特点,采用RFID技术、超声波技术和现场总线技术,设计了国防工程安全管理系统.在介绍了系统架构的基础上,详细阐述了系统的软硬件设计,并对管理系统的软件进行了模块和功能的分析.试验结果表明,该系统能实时显示国防工程中的人员和装备信息,在提高国防工程安全管理的精确化水平方面具有广阔的应用前景.     

Pharmacodynamics of some individual milkweed cardenolides fed to larvae of the monarch butterfly (Danaus plexippus L.)

Adult monarch butterflies,Danaus plexippus L. (Lepidoptera: Danaidae), store only some of the cardenolides present in the larval milkweed (Asclepiadaceae) host. Feeding known doses of individual cardenolides to 4th instar monarch larvae led to more efficient larval tissue incorporation at low doses than at high ones, and favored storage of cardenolide glycosides over genins. A qualitative regulation also occurs during larval feeding; calactin and calotropin were stored as such but uscharidin was rapidly converted to a mixture of calactin and calotropin which were the forms stored by the larvae. Two genins, uzarigenin and digitoxigenin, were stored by larvae as polar cardenolide metabolites.Research supported by National Science Foundation grants DEB 7514266 and DEB 7514266-AO2 (U.C. Davis) and DEB 7514265 (Amherst College).     

信息时代下网络技术安全与网络防御探究

互联网的普及以及计算机的发展,给人们的生活带来了极大的方便,许多的商业活动都是通过网络进行,与此同时网络技术的安全也越来越受到人们的关注,在信息时代下网络技术的开放性和共享性给其带来了巨大的安全威胁,必须要进行全面的网络防御。本文分析了信息时代下保障网络信息安全的重要性,探讨了网络技术安全面临的威胁,并且探究了信息时代下计算机网络防御策略。     

浅谈蜜罐技术在网络安全中的应用简

作为一种主动防御的网络安全技术,蜜罐技术已经成为诱骗攻击者非常有效实用的方法。本文从蜜罐技术的定义、分类、发展情况以及主要技术等方面进行比较系统的解释,最后介绍在网络安全中的应用。     

Feeding rats with liposomes or fish oil differently affects their lipid metabolism

Two n‐3 polyunsaturated fatty acid (PUFA)‐rich diets differing in their chemical and physical forms were given to rats during 2 wk. Liposomes [phospholipids (PL) organized in bilayer structures] made from a natural marine lipid extract or a mixture of fats containing fish oil [similar fatty acids esterified in triacylglycerols (TAG)] were used. The influence of n‐3 PUFA dietary sources on plasma parameters, i.e. TAG, cholesterol and PL concentrations, was investigated. A similar hypotriglyceridemic effect of n‐3 PUFA from liposomes or fish oil was observed. In contrast, feeding rats with liposomes led to different PL and cholesterol patterns. In the plasma of rats fed liposomes, total cholesterol amounts were positively correlated with PL levels. Liposome and fish oil feedings caused a marked increase in the amounts of n‐3 PUFA, which occurred mainly at the expense of n‐6 PUFA. However, the enrichment in n‐3 PUFA in the different plasma lipid classes differed substantially when ingested in the form of fish oil or liposomes. These results were interpreted in terms of different lipid bioavailability and metabolic fate during the digestive steps and in the liver, with the dietary source.     

Flavonoid pigments in chalkhill blue (Lysandra coridon Poda) and other lycaenid butterflies

Nine flavonoids, namely, kaempferol, kaempferol 7-rharanoside, kaempferol 3-rhamnoside, kaempferol 3-glucoside, kaempferol 3-glucoside, 7-rhamnoside, quercetin 3-glucoside, quercetin 3,7-diglucoside, isorhamnetin 3-glucoside, and isorhamnetin 3,7-diglucoside, have been identified in the body and wings of the chalkhill blue butterflyLysandra coridon Poda. Flavonoids have also been found in 15 of a further 17 lycaenid species examined. Analysis of the two-dimensional paper chromatographic flavonoid patterns and aglycone results has shown that the flavonoid content ofL. coridon and the other lycaenids is dependent on the flavonoid content of the larval diet. Differences in the flavonoid patterns ofL. coridon and its leguminous larval food plantsHippocrepis comosa, Anthyllis vulneraria, andLotus corniculatus, indicate that the ingested flavonoids are metabolized byL. coridon or its gut flora before sequestration. Despite the presence of fiavones, glycoflavones, and isoflavones in the larval food plant species, only flavonols are sequestered by the lycaenid species examined. The relationship between lycaenid butterflies and their larval food plants, and the possible role(s) of flavonoids in lycaenids has been discussed. Interactions between ants, plants, flavonoids, and myrmecophilous lycaenids have also been considered.     

Plant Cyanogenesis of <Emphasis Type="Italic">Phaseolus lunatus</Emphasis> and its Relevance for Herbivore–Plant Interaction: The Importance of Quantitative Data

Quantitative experimental results on the antiherbivorous effect of cyanogenesis are rare. In our analyses, we distinguished between the total amount of cyanide-containing compounds stored in a given tissue [cyanogenic potential (HCNp)] and the capacity for release of HCN per unit time (HCNc) from these cyanogenic precursors as a reaction to herbivory. We analyzed the impact of these cyanogenic features on herbivorous insects using different accessions of lima beans (Phaseolus lunatus L.) with different cyanogenic characteristics in their leaves and fourth instars of the generalist herbivore Schistocerca gregaria Forskål (Orthoptera, Acrididae). Young leaves exhibit a higher HCNp and HCNc than mature leaves. This ontogenetic variability of cyanogenesis was valid for all accessions studied. In no-choice bioassays, feeding of S. gregaria was reduced on high cyanogenic lima beans compared with low cyanogenic beans. A HCNp of about 15 μmol cyanide/g leaf (fresh weight) with a corresponding HCNc of about 1 μmol HCN released from leaf material within the first 10 min after complete tissue disintegration appears to be a threshold at which the first repellent effects on S. gregaria were observed. The repellent effect of cyanogenesis increased above these thresholds of HCNp and HCNc. No repellent action of cyanogenesis was observed on plants with lower HCNp and HCNc. These low cyanogenic accessions of P. lunatus were consumed extensively—with dramatic consequences for the herbivore. After consumption, locusts showed severe symptoms of intoxication. Choice assays confirmed the feeding preference of locusts for low over high cyanogenic leaf material of P. lunatus. The bioassays revealed total losses of HCN between 90 and 99% related to the estimated amount of ingested cyanide-containing compounds by the locusts. This general finding was independent of the cyanogenic status (high or low) of the leaf material.     

采前水杨酸处理对哈密瓜果实防御酶的诱导

采用1.0、2.0、3.0 mmol/L水杨酸分别在"蜜农9号"哈密瓜开花前1周、幼果期(花后2周)、果实迅速膨大期(花后3周)和网纹形成期(花后4周)对植株进行4次喷洒.依次在幼果期、膨大期、网纹形成期和成熟期进行取样.分析不同浓度水杨酸处理后果实体内3种防御性酶活性的变化.结果表明:采前1.0、2.0、3.0 mmol/L水杨酸处理均能有效地提高哈密瓜果实中过氧化物酶(POD)、多酚氧化酶(PPO)和苯丙氨酸解氨酶(PAL)活性,尤其以2.0 mmol/L水杨酸处理酶活性增加最为显著.