Photochemical Synthesis of Ultrafine Cubic Boron Nitride Nanoparticles under Ambient Conditions.

Cubic boron nitride (c-BN) is a super-hard material whose hardness increases dramatically with decreasing size. However, c-BN nanoparticles (NPs) with sizes less than 10 nm have never been obtained. Herein we report a simple strategy towards the synthesis of ultrafine c-BN NPs with an average size of 3.5 nm. The method, under ambient conditions, exploits a laser-induced photochemical effect and employs dioxane solution of ammonia borane (AB) as a liquid target. Meanwhile, total dehydrogenation of AB is realized by laser irradiation. Therefore, this approach shows great potential for the preparation of super-hard NPs as well as controllable dehydrogenation.

Synergistic effect of HMGB1 knockdown and cordycepin in the K562 human chronic myeloid leukemia cell line.

The high-mobility group box 1 (HMGB1) protein is a DNA-binding nuclear protein, which is overexpressed in leukemia cells. Cordycepin is characterized by strong antileukemic properties and is regarded as an effective natural compound for leukemia therapy. The aim of the present study was to investigate the impact of HMGB1 knockdown and cordycepin treatment on proliferation, apoptosis, reactive oxygen species (ROS) levels and adhesion of K562 human chronic myeloid leukemia cells. The Cell Counting kit­8 assay was used to determine the proliferation of K562 cells. The cell cycle and apoptosis of K562 cells was determined using flow cytometric analysis. In addition, a cell adhesion assay was performed. Western blotting was used to determine the protein expression of cyclooxygenase 2, Bax, receptor for advanced glycation end-products and Bcl­2. The data collected demonstrated that HMGB1 knockdown combined with cordycepin treatment had significant anti­proliferative and pro­apoptotic effects. In addition, it increased the ROS levels and reduced the adhesion of K562 cells. It was also identified that HMGB1 knockdown had synergistic effects with cordycepin, which aided in accelerating apoptosis, and inhibiting proliferation and adhesion in chronic myeloid leukemia cells. These results indicated that HMGB1 may be used as a potential therapeutic target, with cordycepin having potential as an auxiliary drug. Therefore, it is suggested that HMGB1 knockdown and corycepin treatement may present a promising therapeutic strategy for leukemia.