Efficient assembly and anti-tumor evaluation of novel polycyclic [1,2-a]-fused indoles.

Structurally diverse cyclopenta[4,5]pyrrolo[1,2-a]indoles heterocycles were smoothly constructed in good to excellent yields (up to 99 %) with excellent diastereoselectivities (>19:1 dr) through a novel and facile strategy based on BF3-catalyzed Friedel-Crafts alkylation/Aldol/Dehydrative cyclization cascade reaction. The anti-proliferative activity of these newly synthesized polycyclic indoles was screened, and all the functionalized reductive derivatives exhibited favorable anti-tumor activity. Notably, compound 4ae displayed the remarkable inhibitory activity against MCF-7 and HeLa cells with IC50 values of 4.62 µM and 7.71 µM, respectively. Mechanistically, the representative compound 4ae could effectively induce apoptosis of MCF-7 cells in crediting to up-regulate the relative expression of apoptotic protein BAX/Bcl-2, subsequently activate Pro-caspase 9 and cleave PARP, simultaneously block the cell cycle through down- and up-regulate the expression of cyclin B1 and p53, respectively. Moreover, compound 4ae also exhibited promising antineoplastic efficacy in subcutaneous MCF-7 xenograft mice which manifest significant shrunken tumors conspicuous nuclear apoptotic signal and minimal systemic toxicity. This strategy not only established a novel and efficient method for the assembly of structurally complex indole heterocycles, but also provided a series of compounds possessing attractive anti-cancer activity, which holds immense potential for future biomedical applications.

Generalized Cross-Correlation Strain Demodulation Method Based on Local Similar Spectral Scanning.

Optical fiber measurement technology is widely used in the strength testing of buildings, the health testing of industrial equipment, and the minimally invasive surgery of modern medical treatment due to its characteristics of free calibration, high precision, and small size. This paper presents an algorithm that can improve the range and stability of strain measurements in order to solve the problems of the small range and measurement failure of optical fiber strain sensors based on optical frequency-domain reflectometry (OFDR). Firstly, a Rayleigh scattering model based on the refractive index perturbation of an optical fiber is proposed to study the characteristics of Rayleigh scattering and to guide the strain demodulation algorithm based on the spectral shift. Secondly, a local similar scanning method that can maintain a high similarity by monitoring local Rayleigh scattering signals (LSs) before and after strain is proposed. Thirdly, a generalized cross-correlation algorithm is proposed to detect spectral offset, solving the problem of demodulation failure in the case of a Rayleigh scattering signal with a low signal-to-noise ratio. Experiments show that the proposed method still has high stability when the spatial resolution is 3 mm. The measurement precision is 6.2 µÎµ, which proves that the multi-peaks or pseudo-peaks of the traditional algorithm in the case of a large strain, the high spatial resolution, and the poor signal-to-noise ratio are solved, and the stability of the strain measurement process is improved.