To detect changes in human-to-human transmission of influenza A(H7N9) virus, we analyzed characteristics of 40 clusters of case-patients during 5 epidemics in China in 2013–2017. Similarities in number and size of clusters and proportion of clusters with probable human-to-human transmission across all epidemics suggest no change in human-to-human transmission risk.
Critical micelle concentration (CMC) is a crucial parameter of widely used surfactants, and many methods have been developed for CMC determination. However, the current methods for CMC determination, such as conductive, surface tension, and fluorometric methods, are tedious and time-and sample-consuming because a series of samples with different concentrations of surfactants need to be prepared and measured. Although an economical, simple, and fast titration method for CMC determination (only one sample and several minutes are needed) was reported using changes in the color/fluorescence of ionic organic dyes, it has not been used in practical CMC determination owing to the disadvantages of these dyes: very narrow application range (only suitable for cationic or anionic surfactants) and difficult to identify titration end point, especially using different concentrations (10−300 μM) for the same kind surfactants. Here a C6-unsubstituted tetrahydropyrimidine (THP-T1) was found to possess unique and excellent characteristics in titrated surfactant solutions: above CMC, preferring to dissolve in micelles and showing no emission, and not until near/at CMC, being released from micelles and instantly forming aggregates with strong fluorescence. The fluorescence-turn-on change at CMC (titration end point) is so sensitive that it can be clearly observed without comparison of blank and control of dye concentration, and the concentration (c′ THP ) of THP-T1 in titrated solution at CMC is only about 1 μM for zwitterionic surfactants and 2.5 μM for other kinds of surfactants. The CMC values determined by the THP-T1-based titration method are almost the same as those determined by the fluorometric method using THP-T1 as probe. THP-T1 overcomes the disadvantages of reported dyes for CMC titration and realizes the economical, simple and fast CMC titration of different kinds of surfactants for the first time.
E‐DRS is a novel salvianolic acid A (SAA) analog, which was synthesized from resveratrol (RES) and methyldopate. Its structure is similar to that of SAA, but the 3′,4′‐dihydroxy‐trans‐stilbene group and the ester structure in SAA were replaced by the RES structure and an amine group, respectively. E‐DRS scavenged free oxygen radicals effectively, including superoxide anion (ascorbic acid > E‐DRS > SAA ≥ rutin > RES) and DPPH radical (rutin > E‐DRS ≥ ascorbic acid > SAA > RES), and exhibited powerful total antioxidant capacity (ascorbic acid > E‐DRS > SAA ≥ rutin > RES) in vitro. Furthermore, oral administration of E‐DRS dose‐dependently and significantly decreased CCl4‐induced oxidative stress in mice as indicated by the decreased content of hepatic malondialdehyde (MDA). In addition, oral administration of E‐DRS also increased the content of nonenzymatic antioxidant glutathione (GSH) and the activity of antioxidant enzymes such as catalase (CAT) and superoxide dismutase (SOD) in the liver of mice. All these results demonstrated that E‐DRS had good antioxidant activities both in vitro and in vivo, and could be a potential antioxidant agent after further optimization and evaluation.
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