ABSTRACT
In this paper, we reviewed the current development and patents for the application of high-brightness and high-efficiency white light-emitting diode (LED). The high-efficiency GaN nanostructures, such as disk, pyramid, and rod were grown on LiAlO(2) substrate by plasma-assisted molecular-beam epitaxy, and a model was developed to demonstrate the growth of the GaN nanostructures. Based on the results, the GaN disk p-n junction was designed for the application of high brightness and high efficiency white LED.
Subject(s)
Aluminum Compounds/chemistry , Electrical Equipment and Supplies , Gallium/chemistry , Lighting/instrumentation , Lithium Compounds/chemistry , Nanostructures/chemistry , Nitrogen/chemistry , Conservation of Energy Resources , Microscopy, Electron, Scanning , Microscopy, Electron, Transmission , Models, Molecular , Nanostructures/ultrastructure , Patents as Topic , X-Ray DiffractionABSTRACT
Apoptosis is a particular process that leads to the programmed cell death, and it has been a potentially therapeutic target of cancer. In this study, we evaluated the possible apoptotic effects of glycolic acid on human leukemia cell line (HL-60) in vitro. The morphological changes, cell viability, apoptosis induction, and caspase-3 activity were measured by phase microscopy, flow cytometry, and Western blot analysis. Morphological changes including shrinkage of cells were clearly demonstrated in HL-60 cells treated with increasing concentrations of glycolic acid. Cell viability was significantly affected by glycolic acid treatment in a dose- and time-dependent manner. In comparison to the control group, glycolic acid treatment had a profound effect in the induction of apoptosis by flow cytometric assays. In the cell cycle analysis, glycolic acid caused the increased percentage of cells in G2/M phase and the decreased expression of the cyclin A and cyclin B1, suggesting the induction of G2/M arrest of cell cycle by glycolic acid. Moreover, glycolic acid treatment promoted caspase-9 and -3 activity in a dose-dependent manner, but caspse-8 activity was not affected during the same process. Glycolic acid co-administrated with broad-spectrum caspase inhibitor, z-VAD-fmk, caspase-3 activity was blunted and apoptosis was also markedly blocked in HL-60 cells. In conclusion, glycolic acid-induced apoptosis in HL-60 cells may be through the activation of caspase-3. Future studies focusing on cell signaling and biological significance of glycolic acid-induced apoptosis would lead to exploring the mechanisms of chemotherapeutic potency of glycolic acid in human cancers.
