Content delivery networks are designed to extend the end-to-end transport capability of the Internet to cope with increases in video traffic. For further improvement, bursty request arrivals should be efficiently addr...Content delivery networks are designed to extend the end-to-end transport capability of the Internet to cope with increases in video traffic. For further improvement, bursty request arrivals should be efficiently addressed. As opposed to previous approaches, in which the best client-server pair is individually selected (individual optimization), this paper proposes an algorithm for dealing with simultaneous arrival requests, in which client-server pairs are selected such that all requests receive good service (social optimization). The performance of the proposed algorithm is compared with that of the closest algorithm, an individual optimization algorithm, under the condition that a large number of requests arrive simultaneously. The evaluation criterion is the worst link stress, which is the largest number of streams per link. The numerical results show that the proposed algorithm is effective for large-scale networks and that the closest algorithm does not provide near-optimal solutions, especially when all requests arrive in a small part of the network or when there are many servers.展开更多
The effects of various toxic carbonyls such as malondialdehyde(MDA),a secondary product of lipid peroxidation,and other aldehydes on rheological parameters and their relationship with aging-associated alterations were...The effects of various toxic carbonyls such as malondialdehyde(MDA),a secondary product of lipid peroxidation,and other aldehydes on rheological parameters and their relationship with aging-associated alterations were studied.Both MDA and glutaraldehyde(Glu) in different concentrations significantly increase viscosity,plastic viscosity and yield stress of human plasma and erythrocyte suspensions.MDA(20 mmol/L) reduces sharply the typical fluorescence of proteins(excitation 280 nm/emission 350 nm),and produces age pigment-like fluorescence with a strong emission peak at 460 nm when excites at 395 nm by only being incubated for some hours.In contrast,Glu decreases merely the fluorescence of proteins without producing age pigment-like fluorescence.These data suggest interestingly that the MDA-induced gradual protein cross linking seems to form from different mechanisms compared to the fast rheological changes of blood materials which may take place either in acute and chronic diseases or during aging.On the other hand,MDA induces various deleterious alterations of erythrocytes whereas glutathione(GSH) inhibits the MDA-related carbonyl stress in a concentration-dependent manner.The results indicate that carbonyl-amino reaction exists in the blood widely and GSH has the ability to interrupt or reverse this reaction in a certain way.It implies that carbonyl stress may be one of the important factors in blood stasis and suggests a theoretical and practical approach in anti-stresses and anti-aging.展开更多
Cu-catalyzed oxidation of 5-hexyl-1,3-dihydroimidazo-2-one (1) in the presence of propylamine, as surrogates for the oxidized His side chain and Lys side chain, was investigated. 5-Hexylidene-4-propylamino-1,5-dihydro...Cu-catalyzed oxidation of 5-hexyl-1,3-dihydroimidazo-2-one (1) in the presence of propylamine, as surrogates for the oxidized His side chain and Lys side chain, was investigated. 5-Hexylidene-4-propylamino-1,5-dihydroimidazol-2-one (2), a model His-Lys cross-link product, was isolated and structurally characterized by NMR and mass spectrometry.展开更多
目的 探讨转录因子ZXDC基因敲减对脊髓神经元(SCNs)氧化应激损伤后的保护作用及机制。方法 应用不同浓度H_(2)O_(2)诱导SCNs氧化应激损伤,CCK8检测细胞活性筛选H_(2)O_(2)诱导最佳浓度;实验细胞分为:Control组、H_(2)O_(2)+AAV-NC组和H_...目的 探讨转录因子ZXDC基因敲减对脊髓神经元(SCNs)氧化应激损伤后的保护作用及机制。方法 应用不同浓度H_(2)O_(2)诱导SCNs氧化应激损伤,CCK8检测细胞活性筛选H_(2)O_(2)诱导最佳浓度;实验细胞分为:Control组、H_(2)O_(2)+AAV-NC组和H_(2)O_(2)+AAV-ZXDC siRNA组,免疫荧光染色鉴定原代SCNs,检测各组ZXDC表达和神经突起平均长度;Western bolt检测各组细胞中ZXDC、CCL2、CCR2表达,qRT-PCR检测细胞中炎症因子TNF-α和IL-1β m RNA表达,应用EdU荧光染色、CCK8检测ZXDC对SCNs增殖和活性的影响。结果 筛选600μmol/L H_(2)O_(2)适用于SCNs氧化应激模型制备。β-Ⅲ-tubulin免疫荧光染色鉴定原代SCNs培养成功;与Control组比较,H_(2)O_(2)+AAV-NC组神经突起平均长度显著降低,ZXDC、CCL2和CCR2表达显著增高,而H_(2)O_(2)+AAV-ZXDC siRNA组较H_(2)O_(2)+AAV-NC组神经突起平均长度显著增高,ZXDC、CCL2和CCR2蛋白表达显著降低(P<0.05);与Control组比较,H_(2)O_(2)诱导组TNF-α和IL-1β m RNA相对表达显著增高,细胞增殖和细胞活力显著降低。与H_(2)O_(2)+AAV-NC组比较,H_(2)O_(2)+AAV-ZXDC si RNA组TNF-α和IL-1β m RNA相对表达显著降低,细胞增殖和细胞活力显著增高(P<0.05)。结论 ZXDC基因敲减通过调控CCL2/CCR2信号通路促进氧化应激损伤SCNs细胞增殖、细胞活力和神经突生长。展开更多
文摘Content delivery networks are designed to extend the end-to-end transport capability of the Internet to cope with increases in video traffic. For further improvement, bursty request arrivals should be efficiently addressed. As opposed to previous approaches, in which the best client-server pair is individually selected (individual optimization), this paper proposes an algorithm for dealing with simultaneous arrival requests, in which client-server pairs are selected such that all requests receive good service (social optimization). The performance of the proposed algorithm is compared with that of the closest algorithm, an individual optimization algorithm, under the condition that a large number of requests arrive simultaneously. The evaluation criterion is the worst link stress, which is the largest number of streams per link. The numerical results show that the proposed algorithm is effective for large-scale networks and that the closest algorithm does not provide near-optimal solutions, especially when all requests arrive in a small part of the network or when there are many servers.
基金Project(2007AA02Z433) supported by the National High Technology Research and Development Program of ChinaProject(2007RS4017) supported by the Postdoctoral Science Foundation of Hunan Province,China
文摘The effects of various toxic carbonyls such as malondialdehyde(MDA),a secondary product of lipid peroxidation,and other aldehydes on rheological parameters and their relationship with aging-associated alterations were studied.Both MDA and glutaraldehyde(Glu) in different concentrations significantly increase viscosity,plastic viscosity and yield stress of human plasma and erythrocyte suspensions.MDA(20 mmol/L) reduces sharply the typical fluorescence of proteins(excitation 280 nm/emission 350 nm),and produces age pigment-like fluorescence with a strong emission peak at 460 nm when excites at 395 nm by only being incubated for some hours.In contrast,Glu decreases merely the fluorescence of proteins without producing age pigment-like fluorescence.These data suggest interestingly that the MDA-induced gradual protein cross linking seems to form from different mechanisms compared to the fast rheological changes of blood materials which may take place either in acute and chronic diseases or during aging.On the other hand,MDA induces various deleterious alterations of erythrocytes whereas glutathione(GSH) inhibits the MDA-related carbonyl stress in a concentration-dependent manner.The results indicate that carbonyl-amino reaction exists in the blood widely and GSH has the ability to interrupt or reverse this reaction in a certain way.It implies that carbonyl stress may be one of the important factors in blood stasis and suggests a theoretical and practical approach in anti-stresses and anti-aging.
文摘Cu-catalyzed oxidation of 5-hexyl-1,3-dihydroimidazo-2-one (1) in the presence of propylamine, as surrogates for the oxidized His side chain and Lys side chain, was investigated. 5-Hexylidene-4-propylamino-1,5-dihydroimidazol-2-one (2), a model His-Lys cross-link product, was isolated and structurally characterized by NMR and mass spectrometry.
文摘为了克隆与研究盐胁迫相关的基因,以盐胁迫后的短芒大麦叶片为材料,用Trizol一步法提取总RNA,Oligo(dT)纤维素柱纯化mRNA,反转录合成第一链cDNA和第二链cDNA.cDNA纯化后,与λZAP表达载体连接,体外包装后得到盐胁迫下短芒大麦cDNA文库,其重组率达96%,滴度为2×107 pfu/mL,插入片段长度0.5～3.0 kb.
文摘目的 探讨转录因子ZXDC基因敲减对脊髓神经元(SCNs)氧化应激损伤后的保护作用及机制。方法 应用不同浓度H_(2)O_(2)诱导SCNs氧化应激损伤,CCK8检测细胞活性筛选H_(2)O_(2)诱导最佳浓度;实验细胞分为:Control组、H_(2)O_(2)+AAV-NC组和H_(2)O_(2)+AAV-ZXDC siRNA组,免疫荧光染色鉴定原代SCNs,检测各组ZXDC表达和神经突起平均长度;Western bolt检测各组细胞中ZXDC、CCL2、CCR2表达,qRT-PCR检测细胞中炎症因子TNF-α和IL-1β m RNA表达,应用EdU荧光染色、CCK8检测ZXDC对SCNs增殖和活性的影响。结果 筛选600μmol/L H_(2)O_(2)适用于SCNs氧化应激模型制备。β-Ⅲ-tubulin免疫荧光染色鉴定原代SCNs培养成功;与Control组比较,H_(2)O_(2)+AAV-NC组神经突起平均长度显著降低,ZXDC、CCL2和CCR2表达显著增高,而H_(2)O_(2)+AAV-ZXDC siRNA组较H_(2)O_(2)+AAV-NC组神经突起平均长度显著增高,ZXDC、CCL2和CCR2蛋白表达显著降低(P<0.05);与Control组比较,H_(2)O_(2)诱导组TNF-α和IL-1β m RNA相对表达显著增高,细胞增殖和细胞活力显著降低。与H_(2)O_(2)+AAV-NC组比较,H_(2)O_(2)+AAV-ZXDC si RNA组TNF-α和IL-1β m RNA相对表达显著降低,细胞增殖和细胞活力显著增高(P<0.05)。结论 ZXDC基因敲减通过调控CCL2/CCR2信号通路促进氧化应激损伤SCNs细胞增殖、细胞活力和神经突生长。
