RESUMEN
High-Q factor can enhance the interaction between light and matter, which is an important parameter to decrease the threshold of nanolasers. Here, we theoretically propose an eccentric nanoring structure with a high and controllable Q factor to realize a low-threshold and controllable nanolaser by amplifying the quasi-bound states in the continuum (quasi-BIC). The designed nanostructure supports a quasi-BIC because of the symmetry protection-breaking of the nanostructure. The quasi-BIC has a very high Q factor of about 9.6×104 and can also be adjusted by changing structural parameters. We use the energy level diagram of the four-level two-electron system to study the lasing action of the eccentric nanoring structure. The results show that the nanolaser has a relatively low threshold of about 6.46 µJ/cm2. Furthermore, the lasing behavior can be tuned by controlling the structural parameters of the eccentric circular ring structure.
RESUMEN
BACKGROUND: Chemotherapeutic resistance is a main problem in clinical breast cancer therapy. The purpose of our study is to investigate whether the combination of neoadjuvant chemotherapy and survivin siRNA treatment could enhance the therapeutic effect of neoadjuvant chemotherapy using paclitaxel or epirubicin. MATERIALS AND METHODS: The molecular cloning technique was applied to construct the expression vector of siRNA against survivin. Effectene Transfection Reagent was used to transfect plasmids to MCF-7 cells. Survivin expressions were detected by quantitative real-time PCR (qRT-PCR) and Western blot methods. The effect of paclitaxel or epirubicin, with or without the combination of survivin siRNA treatment, on drug susceptibility of MCF-7 cells was detected by CCK-8 assay. MCF-7 cell apoptosis was detected by Flow Cytometry. RESULTS: Survivin siRNA effectively inhibited the expression of Survivin RNA and protein levels (P < 0.05). Both paclitaxel and epirubicin can suppress the proliferation of MCF-7 cells and induce apoptosis to a certain degree respectively. The combination of survivin siRNA with the two chemotherapy drugs significantly enhanced both effects of the two chemotherapeutics respectively (P < 0.05). CONCLUSION: Survivin siRNA combined with the neoadjuvant chemotherapy can significantly enhance the sensitivity of MCF-7 cells to chemotherapeutics and cell apoptosis. This technology has important potential value in the therapeutic study of breast cancer.