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Xiaolong Mountain, located in warm temperate subtropical transition zone, is one of the important biodiversity conservation areas in China. We analyzed species composition, community structure, and habitat preferences of all woody plant species with DBH (diameter at breast height)≥1 cm in a 6 hm 2 plot in Xiaolong Mountain, Gansu Province, Northwest China. A total of 29251 individuals (41735 stems) belonging to 33 families, 65 genera, and 124 species were recorded. The 28 species with importance value ≥1 contributed 82.9% to the total abundance. The top four species with the highest importance value were Quercus aliena var. acuteserrata , Betula platyphylla , Lindera aggregata var. playfairii and Corylus heterophylla . The structure of DBH size class of all stems showed an inverse 'J' type, indicating a successful regeneration tendency in the understory. Results from the indicator species analysis showed that 11 species had significant habitat prefe-rences, an two species ( Ostrya japonica and Acer stachyophyllum subsp. betulifolium ) had the most obvious preferences. Results from the redundancy analysis and partial methods showed that topographic factors played a dominant role in determining species distribution.

A series of 6 novel 2-amino-4, 5-diarylpyrimidines were synthesized by the reaction of isoflavones with guanidine. They were identified by the spectra of IR, 1H NMR, 13C NMR and elemental analysis. The protective effects of 2-amino-4, 5-diarylpyrimidines against oxygen-glucose deprivation leading by sodium hydrosulfite in PC12 cells were studied by MTT method. It was shown that 2-amino-4, 5-diarylpyrimidines exhibited neuroprotective effects against oxygen-glucose deprivation injury in PC12 cells, which could increase the amount of survival PC12 cells and reduce their injured degree in the model.