[Changes of schistosomiasis endemic situation and water body security in Changsha City section of Xiangjiang River].

OBJECTIVE: To understand the changes of schistosomiasis endemic situation and water body security in the Changsha City section of the Xiangjiang River. METHODS: The prevention and control measures of schistosomiasis, the status of Oncomelania hupensis snails in the marshlands, and the schistosome infection rates of residents on the both sides of the river and boat fishermen were investigated from 2003 to 2012. The schistosome infectivity of the water body was investigate by the method of sentry mice. RESULTS: The snail area decreased from 471 hm(2) in 2003 to 28.81 hm(2) in 2012 with the decline rate of 93.88%. Through the environmental modification, no living snails were found in 9 marshlands among the 11 marshlands, and the density of snails was below 0.006/0.1 m(2) in the other 2 marshlands, but no infected snails were found for 7 years. The original snail habitats of Juzhou scenic area were completely modified and no living snails were found from 2008. In the area, no domestic animals were pastured and the schistosome infectivity of the water body was negative with the sentry mouse method for 10 years. In 2003, the schistosome infection rate was 3.63% in the residents, but no new infections were found in original residents after 2010. CONCLUSION: The endemic situation of schistosomiasis of the Changsha City section of the Xiangjiang River has reached the standards of schistosomiasis transmission controlled and the water body of Juzhou scenic area is safe.

[Effect of cultivation for snail control on schistosomiasis in Changsha urban section of Xiangjiang River].

OBJECTIVE: To study a reliable, friendly environmental and sustainable Oncomelania snail control method in marshlands of the Xiangjiang River. METHODS: According to the special characteristics of the marshlands of the Xiangjiang River, smoothing and cultivating in beaches were applied for snail control. In sections with scarce distribution of snails, lowering parts of 4.4 beaches and raising other parts were added. RESULTS: Since 2003, the project has been practiced for 8 years. The average snail density declined by 99.83% with the simple smoothing beaches and then cultivation there. The average snail density declined by 100% with lowering parts of beaches and raising other parts and then cultivation. The schistosome infection rate was 0.31% with a declined rate of 93.84% in residents in 2006. The schistosome infection rate was 1.03% in 2010. The test result of water contamination was negative. CONCLUSIONS: The method of simple smoothing beaches and then cultivation can control the density of snails in marshlands and the method of lowering parts of beaches and raising other parts and then cultivation is more effective.

A new strategy for the synthesis of 1,4-benzodiazepine derivatives based on the tandem N-alkylation-ring opening-cyclization reactions of methyl 1-arylaziridine-2-carboxylates with N-[2-bromomethyl(phenyl)]trifluoroacetamides.

A new method for the synthesis of novel 1,4-benzodiazepine derivatives has been established from a one-pot reaction of methyl 1-arylaziridine-2-carboxylates with N-[2-bromomethyl(aryl)]trifluoroacetamides. The reaction proceeds through the N-benzylation and highly regioselective ring-opening reaction of aziridine by bromide anion followed by Et3N-mediated intramolecular nucleophilic displacement of the bromide by the amide nitrogen. The easy availability of starting materials, simple and convenient synthetic procedure, and formation of functionalized 1,4-benzodiazepine scaffold ready for further chemical manipulations render this strategy useful in synthetic and medicinal chemistry.