272 research outputs found
Nanometric precision distance metrology via chip-scale soliton microcombs
Laser interferometry serves a fundamental role in science and technology,
assisting precision metrology and dimensional length measurement. During the
past decade, laser frequency combs - a coherent optical-microwave frequency
ruler over a broad spectral range with traceability to time-frequency standards
- have contributed pivotal roles in laser dimensional metrology with
ever-growing demands in measurement precision. Here we report
spectrally-resolved laser dimensional metrology via a soliton frequency
microcomb, with nanometric-scale precision. Spectral interferometry provides
information on the optical time-of-flight signature, and the large
free-spectral range and high-coherence of the microcomb enables tooth-resolved
and high-visibility interferograms that can be directly readout with optical
spectrum instrumentation. We employ a hybrid timing signal from comb-line
homodyne interferometry and microcomb spectrally-resolved interferometry - all
from the same spectral interferogram. Our combined soliton and homodyne
architecture demonstrates a 3-nm repeatability achieved via homodyne
interferometry, and over 1,000-seconds stability in the long-term precision
metrology at the white noise limits.Comment: 24 pages, 12 figure
Association Between Genetic Variant in the Promoter of Pri-miR-34b/c and Risk of Glioma
Growing evidence indicates that p53 can regulate the expression of miRNAs, particularly the miR-34 family members, which are described as potential tumor suppressors. Loss of miR-34 suppresses TP53-mediated cell death, whereas over expression of miR-34 induced apoptosis. The study designed to investigate the association between the pir-miR-34b/c rs4938723, TP53 Arg72Pro and the risk of glioma. We genotyped the two polymorphisms in175 glioma patients and 235 healthy controls using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and DNA sequencing assay. Association analysis showed that the CC genotype of the pir-miR-34b/c rs4938723 was associated with a significantly decreased risk of glioma compared to the TT genotype (CC vs. TT: adjusted OR = 0.43;95% CI, 0.21–0.87,P = 0.02). Moreover, a significant association between the patients with glioma and controls was also observed in a recessive model (OR = 0.41; 95% CI, 0.21–0.81, P = 0.007). In contrast, the CC genotype of the TP53 Arg72Pro was associated with a significantly increased risk of glioma compared to the GG genotype (CC vs. GG: adjusted OR = 1.73;95% CI, 1.04–2.89,P = 0.04), and a significant association between the patients with glioma and controls was also observed in a recessive model (OR = 2.00; 95% CI, 1.26–3.18, P = 0.003). These findings suggest that the pri-miR-34b/c rs4938723CC and TP53 Arg72-Pro polymorphisms may be associated with the risk of glioma
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