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Under unstable wind loads, the wind turbine tower, as a supporting component of the horizontal axis experiences inevitable vibration. To explore the vibration characteristics of the tower, a vehicle test platform is established to measure the vibration acceleration component signals at different heights of a 300W small horizontal axis wind turbine tower. The results show that specific vehicle vibration test equipment can accurately test the vibration characteristics and laws of small wind turbine towers. The main vibration form of the tower is low frequency, with noticeable axial vibration at the top and lateral vibration in the middle of the tower due to aerodynamic load from natural wind. These findings can be used as a valuable reference for the safety and reliability design of the whole machine and the low-frequency vibration status monitoring of wind turbines. [ABSTRACT FROM AUTHOR]

Anthocyanins and selenium (Se) have antioxidant properties and are crucial to human health. Previous works have well studied the role of exogenous Se fertilization in grain quality and anthocyanin formation in colored crops, whereas few reports on naturally Se-enriched colored grains exist. In this study, the quality, anthocyanin accumulation, and metabolism of natural Se-enriched purple waxy corn and common purple waxy corn were compared during kernel development. Natural Se-enriched purple waxy corn had higher concentrations of total Se, anthocyanins, flavones, starch (branched- and straight-chain), and sugar than common purple waxy corn, and the optimum eating date was 28 days after pollination. Genes related to anthocyanin biosynthesis were significantly upregulated in natural Se-enriched purple waxy corn, resulting in enriched anthocyanin metabolites (6-O-malonyl-beta-D-glu and 3-O-glu in Cy, Pn, and Pg). Most importantly, genetic alterations were observed which several genes and transcription factors were downregulated some branch pathways of lignin synthesis and accelerated anthocyanin synthesis. Our results profiled anthocyanin metabolism in naturally Se-enriched purple waxy corn to promote harvesting. [ABSTRACT FROM AUTHOR]

Background Sexual transmission chains of Ebola virus (EBOV) have been verified and linked to EBOV RNA persistence in semen, post-recovery. The rate of semen persistence over time, including the average duration of persistence among Ebola virus disease (EVD) survivors, is not well known. This cohort study aimed to analyze population estimates of EBOV RNA persistence rates in semen over time, and associated risk factors in a population of survivors from Sierra Leone. Methods and findings In this cohort study from May 2015 to April 2017 in Sierra Leone, recruitment was conducted in 2 phases; the first enrolled 100 male participants from the Western Area District in the capital of Freetown, and the second enrolled 120 men from the Western Area District and from Lungi, Port Loko District. Mean age of participants was 31 years. The men provided semen for testing, analyzed by quantitative reverse transcription PCR (qRT-PCR) for the presence of EBOV RNA. Follow-up occurred every 2 weeks until the endpoint, defined as 2 consecutive negative qRT-PCR results of semen specimen testing for EBOV RNA. Participants were matched with the Sierra Leone EVD case database to retrieve cycle threshold (Ct) values from the qRT-PCR analysis done in blood during acute disease. A purposive sampling strategy was used, and the included sample composition was compared to the national EVD survivor database to understand deviations from the general male survivor population. At 180 days (6 months) after Ebola treatment unit (ETU) discharge, the EBOV RNA semen positive rate was 75.4% (95% CI 66.9%-82.0%). The median persistence duration was 204 days, with 50% of men having cleared their semen of EBOV RNA after this time. At 270 days, persistence was 26.8% (95% CI 20.0%-34.2%), and at 360 days, 6.0% (95% CI 3.1%-10.2%). Longer persistence was significantly associated with severe acute disease, with probability of persistence in this population at 1 year at 10.1% (95% CI 4.6%-19.8%) compared to the probability approaching 0% for those with mild acute disease. Age showed a dose-response pattern, where the youngest men ([less than or equal to]25 years) were 3.17 (95% CI 1.60, 6.29) times more likely to be EBOV RNA negative in semen, and men aged 26-35 years were 1.85 (95% CI 1.04, 3.28) times more likely to be negative, than men aged >35 years. Among participants with both severe acute EVD and a higher age (>35 years), persistence remained above 20% (95% CI 6.0%-50.6%) at 1 year. Uptake of safe sex recommendations 3 months after ETU discharge was low among a third of survivors. The sample was largely representative of male survivors in Sierra Leone. A limitation of this study is the lack of knowledge about infectiousness. Conclusions In this study we observed that EBOV RNA persistence in semen was a frequent phenomenon, with high population rates over time. This finding will inform forthcoming updated recommendations on risk reduction strategies relating to sexual transmission of EBOV. Our findings support implementation of a semen testing program as part of epidemic preparedness and response. Further, the results will enable planning of the magnitude of testing and targeted counseling needs over time., Author(s): A. E. Thorson 1,2,*, G. F. Deen 3, K. T. Bernstein 4, W. J. Liu 5, F. Yamba 3, N. Habib 1, F. R. Sesay 6, P. Gaillard 1, [...]