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In order to decrease the soil nutrient loss in young planted Chinese fir ͑Cunningharnia lanceolata ͑Lamb.͒ Hook.͒ forestland and to investigate the impact of young Chinese fir plantation intercropped with crops on soil quality, a field experiment was set up in the mid-subtropics of China in 1998. The effects of growing crops in combination with young Chinese fir on soil properties were evaluated by measuring physico-chemical, microbiological and biochemical parameters five years after the beginning of this experiment. Three treatments were selected in the experiment, i.e., Chinese fir plantation intercropped with peanut ͑Arachis hypogaea L.͒-wheat ͑Triticum aestivum L.͒ cropping sequence ͑C-P/W͒; Chinese fir plantation intercropped with maize ͑Zea mays L.͒-wheat cropping sequence ͑C-M/W͒ and only Chinese fir plantation ͑Control͒. Soils were sampled at the 0-10 cm depth in 2003. The increases in soil nutrients ͑especially with respect to soil available nutrients͒, soil microbial biomass C ͑SMBC͒, microbial quotient ͑MQ͒, soil basal respiration ͑SBR͒, microbe numbers and enzyme activities and slight decrease in metabolic quotient ͑qCO 2 ͒ as well as melioration in soil structure and humus quality were observed in tree-crop combinations compared with sole plantation of Chinese fir, although the differences were not always statistically significant. In addition, the evidence obtained from this study also suggests that Chinese fir-crop combination can promote the growth of young Chinese fir. Therefore, growing crops in combination with young Chinese fir can be considered a good forest management practice, helping to limit the gradual depletion of soil nutrients and, at the same time, to some degree controlling the degradation of planted Chinese fir forestland.

The monitoring of folate receptor levels in living cancer cells has attracted increasing interest; however, the present fluorescence probes used often suffer from interference from nonspecific adsorption on the surface of non-target cells. In the present study, the probe is readily prepared by using folic acid as template molecule, a mesoporous silica nanoparticle as an imprinting material, and a CdTe quantum dot as a signal transducer for the recognition of folate receptor. This system is expected to offer specific recognition of folate receptor over other substances based on the high affinity of folic acid and folate receptor. The probe is stable and monodispersed in aqueous suspension, and has little toxicity to living cells and thus can be utilized for targeted A549 cell imaging. The living cell imaging experiments further demonstrate its value in bioimaging cell-surface folate receptor by virtue of its superior biocompatibility, lower cytotoxicity and membrane permeability.