[Morphological and microscopical identification of Genkwa Ramulus and its adulterants].

The purpose of this article is to identify Daphne genkwa and its adulterants, Wikstroemia chamaedaphne, according to the morphological and microstructure characteristics of their stem and foliage. The root of D.genkwa was studied simultaneously. The results indicated that the crude drug and processed pieces of Genkwa Ramulus were mainly composed of stems and branches where obvious opposite petiole scars and branch marks were able to be seen on their nodes. Otherwise, foliage or peduncles generally couldn't be found. Moreover, the fine silver flocculent fibers could be observed in the bark of fracture surface. The adulterants were the plant segments which were composed of stems, foliage and peduncles with spikelet-pedicel scars. There existed microstructures differences between Genkwa Ramulus and its adulterants. In the former, single thick lignified phloem fibers were interspersed in the stem phloem of the transverse section with very thick wall and unicellular non-glandular hairs could be observed on the lower epidermis of foliage. Nevertheless, in the latter, there was no thick lignified phloem fibers in cross section of stem phloem, the outer wall of epidermal cells of foliage hadthick cuticles and no non-glandular hairs in lower epidermis of foliage. The results can be used for the identification and the quality standard of the crude drug and processed pieces of D.genkwa.The characteristics of the microstructures and the transverse section can be used to identify the radix D.genkwa.

Easily prepared high-quantum-yield CdS quantum dots in water using hyperbranched polyethylenimine as modifier.

Some research has reported interaction between polyamidoamine dendrimers or polyethylenimine and quantum dots causing a quantum yield decrease of quantum dots. In this work, however, polyethylenimines of different molecular weight that were used to modify CdS quantum dots gave rise to the enhancement of CdS quantum yield to nearly 100%. Herein, we present the synthesis of a kind of easily prepared high-quantum-yield CdS quantum dot in aqueous solution and the study of the interaction between CdS and polyethylenimine.