ABSTRACT
Although sediments are considered to be a major sink for microplastics (MP), there is still a relative lack of knowledge on the factors that influence the occurrence and abundance of MP in riverine sediments. The present study investigated the occurrence and distribution of MP in riverine sediments collected at twelve sites representative of different populated and urbanized rivers (To Lich, Nhue and Day Rivers) located in the Red River Delta (RRD, Vietnam, during dry and rainy seasons. MP concentrations ranged from 1600 items kg-1 dw to 94,300 items kg-1dw. Fiber shape dominated and MP were made of polypropylene (PP) and polyethylene (PE) predominantly. An absence of seasonal effect was observed for both fragments and fibers for each rivers. Decreasing MP concentrations trend was evidenced from the To Lich River, to the Nhue River and to the Day River, coupled with a decreasing fiber length and an increasing fragment area in the surface sediment from upstream to downstream. Content of organic matter was correlated to MP concentrations suggesting that, high levels of organic matter could be MP hotspots in urban rivers. Also, high population density as well as in highly residential areas are related to higher MP concentrations in sediments. Finally, a MP high ecological risk (RI: 866 to 4711) was calculated in the RDD.
ABSTRACT
A new labdane-type diterpenoid, named vitexnegundin (1), along with seven known compounds, including vitexilactone (2), vitetrifolin D (3), 13-hydroxy-5(10),14-halimadien-6-one (4), (rel 3S,5S,8R,9R,10S)-3,9-dihydroxy-13(14)-labden-16,15-olide (5), artemetin (6), vitexcarpin (7) and penduletin (8), were isolated from the leaves of Vitex negundo L. Their structures were elucidated by using spectroscopic methods, X-ray crystallographic analysis and comparison with those reported in the literature. Moreover, all isolated compounds 1-8 were evaluated for their antimicrobial activity against ESBL-producing Escherichia coli strain and methicillin-resistant Staphylococcus aureus.
Subject(s)
Diterpenes/isolation & purification , Plant Leaves/chemistry , Vitex/chemistry , Anti-Infective Agents/pharmacology , Methicillin-Resistant Staphylococcus aureus/drug effects , Microbial Sensitivity Tests , Proton Magnetic Resonance SpectroscopyABSTRACT
Study on the therapeuctic effects of CV8 in 1614 uncomplicated malaria patients (878 P.falciparum and 736 P.vivax) in Binh Thuan district during 2002-2003. The patients were monitored for 28 days after treatment. The results showed that: the rate of re-appearance of parasite found during follow-up was 0.3% for P.falciparum and 0.5% for P.vivax. Using WHO guidelines, CV8 had high therapeutic efficacy, inconsiderable side effects and good compliance. The cure rate in patients infected P.falciparum was 99.7% and P.vivax was 99.5%
