Non-Interpenetrated Single-Crystal Covalent Organic Frameworks.

Growth of covalent organic frameworks (COFs) as single crystals is extremely challenging. Inaccessibility of open-structured single-crystal COFs prevents the exploration of structure-oriented applications. Herein we report for the first time a non-interpenetrated single-crystal COF, LZU-306, which possesses the open structure constructed exclusively via covalent assembly. With a high void volume of 80 %, LZU-306 was applied to investigate the intrinsic dynamics of reticulated tetraphenylethylene (TPE) as the individual aggregation-induced-emission moiety. Solid-state 2 H NMR investigation has determined that the rotation of benzene rings in TPE, being the freest among the reported cases, is as fast as 1.0×104  Hz at 203 K to 1.5×107  Hz at 293 K. This research not only explores a new paradigm for single-crystal growth of open frameworks, but also provides a unique matrix-isolation platform to reticulate functional moieties into a well-defined and isolated state.

[Effect of comprehensive control and management of schistosomiasis at plateaus regions in Yunnan Province].

OBJECTIVE: To evaluate the effect of comprehensive control and management of schistosomiasis at plateaus regions in Yunnan Province. METHODS: Xiaolian and Kangfu villages at plateaus regions where schistosomiasis was endemic were selected as study areas from 2006 to 2011, the schistosomiasis comprehensive control measures were conducted, and these measures included the health education, chemotherapy, stool and water management, grazing forbidden, Oncomelania snail control, etc. combined with the infrastructure of farmland water conservancy, agricultural comprehensive development, adjustment of industry structure, returning farmland to forest, ditch hardening, and aquaculture. RESULTS: At Xiaolian Village, no schistosomiasis patient and livestock were found from 2008; and at Kangfu Village, no schistosomiasis patient was detected from 2006 and no schistosomiasis domestic animal was found from 2008. In 2011, the snail area, percent of frames with living snails, the number of snails, average concentration of living snails, and the highest concentration of living snails descended by 69.99%, 81.86%, 88.86%, 89.71%, 57.95% at Xiaolian Village, and descended by 27.65%, 1.11%, 94.71%, 92.16%, 88.00% at Kangfu Village, respectively, compared with those in 2006. The ratios of infected snail area to snail area were 68.91% in 2006 and 69.13% in 2007 at Xiaolian Village, and 61.73% in 2006 and 43.24% in 2007 at Kangfu Village. There were no infected snails from 2008 in the two villages. CONCLUSION: The comprehensive control and management measures can effectively control the schistosomiasis prevalence at plateaus regions.