ABSTRACT
Here, we report the synthesis, structure, and single-molecule conductance of three o-carborane-based molecular wires (ortho-, meta- and para-CN) with multiple conduction channels. The effect of connectivity in target wires compared with the corresponding phenyl-centered wires was studied using the scanning tunneling microscope break junction (STM-BJ) technique and theoretical calculations. Interestingly, the three-dimensional structure in o-carborane-based wires can effectively promote the through-space transmission paths or the formation of stable molecular junctions compared to the corresponding phenyl-centered wires. Moreover, the significant conductance difference of o-carborane-based wires was due to the combination of multiple conduction channels and quantum interference. Understanding the effects of different bridging groups and anchor group substitution patterns provides guidelines for designing o-carborane-based multichannel molecular wires.
ABSTRACT
OBJECTIVE: To screen high-risk population of breast cancer by analyzing the risk factors of breast cancer in Guangdong Province. METHODS: A case-control study was performed to identify the risk factors of breast cancer between premenopausal women and postmenopausal women. Chi-square test and unconditional logistic regression were used to analyze the data. RESULTS: In premenopausal women, prophylactic, family history of breast cancer, bad mood, bad life incidence and work load were the risk factors, and breast hyperplasia history, breast tissue examination history, regular exercise and sleeping without bra were the protective factors. In postmenopausal women, family history of breast cancer was the risk factor, and breast hyperplasia history and mood adjustment were the protective factors. CONCLUSION: The risk and protective factors of breast cancer differ between premenopausal and postmenopausal women, which highlights the importance of using different risk models to screen the high-risk populations.
