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This paper demonstrates an unequal-path phase-shifting interferometer for precise optical surface measurement using a femtosecond laser. According to the periodic low temporal coherence of the femtosecond laser, the relative time delay between pulses from the reference and target surfaces is scanned by sweeping the repetition frequency for phase shifting when the optical path length difference is set to integer times of the pulse interval, which removes mechanical scanning devices in the interferometer. In particular, we employ an iterative least-squares fitting algorithm to derive the phase. With this method, a glass slide surface is reconstructed that agrees well with the surface measured using a commercial Fizeau interferometer. The comparison results show that the difference in the peak-to-valley value is 0.050 μm. [ABSTRACT FROM AUTHOR]

Dispersive interferometry based on optical frequency combs has been widely applied in long-distance ranging, refractive index measurements of solids, and optical coherence tomography. In this study, we propose a theoretical model to analyze the influence of spectral resolution that can explain the relationship between the interference contrast of the interference spectrum and the variation in the measured distance with the resolution of a spectrometer. It can also be used to compensate for the systematic error caused by the resolution of the spectrometer. Our proposed model was verified experimentally, and the relative difference between the experimental and the theoretical results was less than 0.003%. [ABSTRACT FROM AUTHOR]

We propose a surface measurement method based on optical frequency comb heterodyne interferometry ranging. A digital micromirror device is used to establish a single-pixel detection system without a mechanical scanning device and realize high-speed sampling. The measurement range of the step height is extended by synthetic wavelength interferometry from half of the carrier wavelength to half of the synthetic wavelength (40 μm in this system). Thus, a sample composed of three gauge blocks and an MEMS device of the teardrop-shaped groove were measured with an accuracy of 5 nm and a measurement time of 27 ms. [ABSTRACT FROM AUTHOR]

Chromodomain helicase DNA-binding protein 5 (CHD5) plays a crucial tumor suppressor role in multiple types of tumors. For this study, we investigated its clinical significance and the molecular mechanism(s) underlying tumorigenesis in renal cell carcinoma (RCC). Initially, CHD5 expression was assessed in primary tumor tissue and in tissue array. Correlations among CHD5 expression and clinicopathological characteristics were analyzed. Next, lentivirus-mediated CHD5 overexpression in the ACHN and 769-P cells was used to assess effects on proliferation, migration, invasion ability, and the regulation of the p14ARF/p53 and p16INK4a/RB signaling pathways. Finally, a xenograft mouse model was used to verify its impact on tumor growth in vivo. Results demonstrated that CHD5 was downregulated in tumor tissues and that low CHD5 expression was correlated with advanced TNM stage, high Fuhrman grade, lymph node metastasis, and poor survival. Overexpression of CHD5 inhibited proliferation, migration, and invasion in vitro; prompted cell cycle G1 phase arrest; induced apoptosis; and suppressed tumor growth in vivo. Furthermore, we confirmed that CHD5 activates the p53 and RB pathways to inhibit tumorigenesis in RCC. In summary, CHD5 is involved in the initiation and progression of RCC and may serve as a diagnostic biomarker and a potential therapeutic target for RCC. [ABSTRACT FROM AUTHOR]