The physics of a system with broken symmetry is rich and interesting. Second harmonic generation (SHG) is one of the most useful methods for investigating surfaces, since it is only sensitive to the few layer surface atoms with broken spatial symmetry. Ultrafast surface SHG is especially useful for investigating nonlinear optics in nanophotonics. Although nano-optics is seen as a natural extension of conventional optics, the nonlinear optics aspect is non-trivial. Recently some groups have found that geometric shape greatly affects the nonlinear signal intensity in a nano-system. With identical area, the one with optimized shape can lead to two orders of magnitude enhancement in the SHG intensity. However, so far there is no clear understanding about the physical origin of this shape resonance effect.
Researchers from Shanghai Institutes for Biological Sciences found that TRAF6 upregulated expression of hypoxia-inducible factor 1(HIF–1). HIF–1 is a transcription factor and plays an important role in angiogenesis and tumorigenesis.
Dr. HUANG Wei from Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden used Triadica sebifera as a study system to examine how plant mediates interactions between aboveground adults and belowground larvae of a specialist flea beetle, Bikasha collaris. Studies showed that aboveground feeding adults increased the performance of belowground feeding conspecific larvae, while larvae negatively impacted adult performance.
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