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1.
介绍了网络通信中对通信关系进行保护的工具TOR,并剖析了目前针对TOR的一种端到端计时攻击方法。针对该攻击方法,提出一个对TOR工作机制的改进方案,通过多数据流多路径混合路由机制来防御攻击,并对其实现方案和安全性进行了分析。 相似文献
2.
A new bimetallic oxycarbide was synthesized and characterized by XRD, TEM, EDS, XPS and adsorption–desorption of probe molecules.
All the molybdenum was reduced and 35% of tungsten was present as WOx. The number of metallic sites, Lewis and Br?nsted acid sites were estimated. A turnover rate of 0.1 s−1 was measured at 300 °C for the first order n-heptane isomerization. 相似文献
3.
A fast and simple analytical procedure, based on capillary zone electrophoresis (CZE), for separation of underivatized low molecular weight lignin-derived sulphonates has been developed. Optimal CZE-operatipn conditions for the separation and detection of several lignin-derived sulphonic acids was found when using a low pH (pH 1.7) phosphate buffer system, an applied voltage of 20 kV and UV-detection at the anode-side. At these conditions the electroosmotic flow is negligible and the analytes are transported through the capillary column by electromigration. The sulphonation and subsequent degradation of the lignin-model compound 1-(4-hydroxy-3-methoxyphenyl)-2-O-(2-methoxyphenyl)-glycerol has been studied by CZE-analysis of aliquots taken from a sulphite reaction mixture No sample pretreatment was needed before analyzing the sulphite reaction mixture with CZE. The method has also been found to be useful for detection of sulphonic acids in samples from sulphite cooking. Crude extracts of a sulphite cooking liquor could be directly analysed by using the technique developed. Based on migration time data and comparison with an authentic sample, 1-(4-hydroxy-3-meth6xyphenyl)-prop-2-ene-1-sulphonate was identified as one of the sulphonic acids present in the sulphite cooking liquor. 相似文献
4.
trans-Polyoctenylene rubber, TOR, was melt blended with different types of rubber in various proportions in a Brabender Plasti-corder. Energy consumption in mixing the blends indicated that TOR is an effective processing aid for a variety of rubber and inclusion of TOR in a blend can result in significant saving of energy. TOR of lower molecular weight (e.g. Vestenamer 8012) performs significantly better than TOR of higher molecular weight (e.g. Vestenamer 6213), both as a processing aid and as a dimension stabilizer. 相似文献
5.
随着互联网应用的不断增加,人们对网络通信的保密性也越来越重视。Tor匿名通信系统具有低时延、数据加密传输,安全信道等优点,能够有效保护通信者的信息安全,目前正成为一种流行的匿名通信系统。但随着Tor系统使用和研究的人增多,Tor系统本身的一些缺陷给其安全带来了隐患。为此,在现有Tor系统分析的基础上,文中提出了一种安全新型的混合匿名转发系统H—Tor。该系统由Hordes和Tor有效级联组合,充分发挥了两者的优势。分析表明,H—Tor可以抵御通信流攻击和端对端攻击,有效保护通信者的匿名安全。 相似文献
6.
Zhi-Han Lin Shun-Ya Chang Wen-Chi Shen Yen-Hung Lin Chiu-Lun Shen Sin-Bo Liao Yu-Chun Liu Chang-Shi Chen Tsui-Ting Ching Horng-Dar Wang 《International journal of molecular sciences》2023,24(1)
Altered metabolism is a hallmark of aging. The tricarboxylic acid cycle (TCA cycle) is an essential metabolic pathway and plays an important role in lifespan regulation. Supplementation of α-ketoglutarate, a metabolite converted by isocitrate dehydrogenase alpha-1 (idha-1) in the TCA cycle, increases lifespan in C. elegans. However, whether idha-1 can regulate lifespan in C. elegans remains unknown. Here, we reported that the expression of idha-1 modulates lifespan and oxidative stress tolerance in C. elegans. Transgenic overexpression of idha-1 extends lifespan, increases the levels of NADPH/NADP+ ratio, and elevates the tolerance to oxidative stress. Conversely, RNAi knockdown of idha-1 exhibits the opposite effects. In addition, the longevity of eat-2 (ad1116) mutant via dietary restriction (DR) was reduced by idha-1 knockdown, indicating that idha-1 may play a role in DR-mediated longevity. Furthermore, idha-1 mediated lifespan may depend on the target of rapamycin (TOR) signaling. Moreover, the phosphorylation levels of S6 kinase (p-S6K) inversely correlate with idha-1 expression, supporting that the idha-1-mediated lifespan regulation may involve the TOR signaling pathway. Together, our data provide new insights into the understanding of idha-1 new function in lifespan regulation probably via DR and TOR signaling and in oxidative stress tolerance in C. elegans. 相似文献
7.
8.
Huachun Sheng Shuangxi Zhang Yanping Wei Shaolin Chen 《International journal of molecular sciences》2021,22(24)
In plants, seedling growth is subtly controlled by multiple environmental factors and endogenous phytohormones. The cross-talk between sugars and brassinosteroid (BR) signaling is known to regulate plant growth; however, the molecular mechanisms that coordinate hormone-dependent growth responses with exogenous sucrose in plants are incompletely understood. Skotomorphogenesis is a plant growth stage with rapid elongation of the hypocotyls. In the present study, we found that low-concentration sugars could improve skotomorphogenesis in a manner dependent on BR biosynthesis and TOR activation. However, accumulation of BZR1 in bzr1-1D mutant plants partially rescued the defects of skotomorphogenesis induced by the TOR inhibitor AZD, and these etiolated seedlings displayed a normal phenotype like that of wild-type seedlings in response to both sucrose and non-sucrose treatments, thereby indicating that accumulated BZR1 sustained, at least partially, the sucrose-promoted growth of etiolated seedlings (skotomorphogenesis). Moreover, genetic evidence based on a phenotypic analysis of bin2-3bil1bil2 triple-mutant and gain-of-function bin2–1 mutant plant indicated that BIN2 inactivation was conducive to skotomorphogenesis in the dark. Subsequent biochemical and molecular analyses enabled us to confirm that sucrose reduced BIN2 levels via the TOR–S6K2 pathway in etiolated seedlings. Combined with a determination of the cellulose content, our results indicated that sucrose-induced BIN2 degradation led to the accumulation of BZR1 and the enhancement of cellulose synthesis, thereby promoting skotomorphogenesis, and that BIN2 is the converging node that integrates sugar and BR signaling. 相似文献
9.
广播式自动相关监视(ADS-B)的延迟时间对监视精度有较大的影响,为了提高ADS-B的监视精度,提出一种精确计算每个ADS-B报文延迟时间的方法。根据ADS-B报文的接收时间和报文内容,可计算两相邻报文的时间间隔和对应报文中飞机两相邻位置的时间间隔,通过对两种时间间隔求差可得到ADS-B两相邻报文的延迟时间差,在初始报文中或者间隔一定时间发送飞机位置测量时刻的条件下,可计算其后所有报文的延迟时间,从而对延迟时间进行修正。最后在15min、25min和45min的ADS-B报文中分别随机选取1架飞机的报文利用Excel对该方法的可行性进行了分析。分析结果表明,采用该方法ADS-B的监视精度得到了很大的提高,在场面滑行的情况下,监视精度小于10m,满足场面监视的需要。 相似文献
10.
Jane Muncke 《The Science of the total environment》2009,407(16):4549-4559
Contamination of foodstuffs by environmental pollutants (e.g. dioxins, metals) receives much attention. Until recently, food packaging as a source of xenobiotics, especially those with endocrine disrupting properties, has received little awareness despite its ubiquitous use. This article reviews the regulations and use of endocrine disrupting compounds (EDCs) in food packaging and discusses their presence within the context of new toxicology paradigms.I focused on substances known to be legally used in food packaging that have been shown to exhibit endocrine disruptive effects in biological systems. I compiled a list of 50 known or potential EDCs used in food contact materials and examined data of EDCs leaching from packaging into food, with a focus on nonylphenol. I included recent advances in toxicology: mixture effects, the developmental origins of adult disease hypothesis, low-dose effects, and epigenetics. I especially considered the case of bisphenol A. The core hypothesis of this review is that chemicals leaching from packaging into food contribute to human EDCs exposure and might lead to chronic disease in light of the current knowledge.Food contact materials are a major source of food contaminants. Many migrating compounds, possibly with endocrine disruptive properties, remain unidentified. There is a need for information on identity/quantity of chemicals leaching into food, human exposure, and long-term impact on health. Especially EDCs in food packaging are of concern. Even at low concentrations, chronic exposure to EDCs is toxicologically relevant. Concerns increase when humans are exposed to mixtures of similar acting EDCs and/or during sensitive windows of development. In particular, non-intentionally added substances (NIAS) migrating from food contact materials need toxicological characterization; the overall migrate of the finished packaging could be evaluated for biological effects using bioassays. The widespread legal use of EDCs in food packaging requires dedicated assessment and should be updated according to contemporary scientific knowledge. 相似文献