A retrospective investigation was conducted to evaluate the effectiveness of DDT residual indoor spraying and bed nets impregnated with pyrethroid insecticide for Japanese encephalitis control in ...southern Henan province, China. DDT residual indoor spraying had no effect on the incidence of Japanese encephalitis, but it was greatly reduced after the introduction of pyrethroid-impregnated bed nets. Only a small effect on outdoor biting densities of Culex tritaeniorhyncus was found, although the number of mosquitoes resting inside bed nets decreased markedly after the introduction of bed net impregnation.
A population-based case-control study to evaluate the protective effect of bed nets impregnated with pyrethroid insecticide and of vaccination against Japanese encephalitis was carried out in Gusi ...county, Henan province, China from June to September 1991; 50 cases and 100 matched controls were studied. Bed nets impregnated with pyrethroid insecticide greatly decreased the risk of infection among children under 10 years old, and vaccine efficacy was 78% (95% CI 16%-94%). We suggest that impregnated bed nets could be used as a quick response during outbreaks of Japanese encephalitis.
Recently, ZrTe\(_5\) has received a lot of attention as it exhibits various topological phases, such as weak and strong topological insulators, a Dirac semimetal, and a quantum spin Hall insulator in ...the monolayer limit. While most of studies have been focused on the three-dimensional bulk material, it is highly desired to obtain nanostructured materials due to their advantages in device applications. We report the synthesis and characterizations of ZrTe\(_5\) nanoribbons. Via a silicon-assisted chemical vapor transport method, long nanoribbons with thickness as thin as 20 nm can be grown. The growth rate is over an order of magnitude faster than the previous method for growth of bulk crystals. Moreover, transport studies show that nanoribbons are of low unintentional doping and high carrier mobility, over 30,000 cm\(^2\)/Vs, which enable reliable determination of the Berry phase of \(\pi\) in the \(ac\) plane from quantum oscillations. Our method holds great potential in growth of high quality ultra-thin nanostructures of ZrTe\(_5\).
Polysiphonia urceolata is one type of potential commercial red seaweeds used for breeding and cultivation, because of its significant biochemical and biomedical application. However, the information ...of breeding and seedling incubation for cultivation is limited, especially the early development. In this study, tetrasporohyte and gametophyte of P. urceolata were taken as the study materials in Huiquan Bay, Qingdao, China. The cleaned and sterilized tetrasporophytes and gametophytes were pre-cultured in sterilized seawater, then nurtured at 18C, 25 kmol photons m super(-2) s super(-1) in 12:12 h (light:dark) photoperiod. Continuous observation under microscope showed that the early development consists of bipolar division stage and seedling stage. In the division stage, tetraspores germinate into bipolar sporelings that further differentiate into a colorless rhizoidal portion and a lightly pigmented upright shoot. The lightly pigmented rhizoidal cell develops to a rhizoid and the larger pigmented cell transforms to an erect axis. In the seedling stage, several quasi-protuberances appear on the erect axis and form juvenile seedlings. The results demonstrate the culture of P. urceolata from tetraspores under laboratory conditions.
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