[Logistic regression analysis of risk factors for subretinal fluid after rhegmatogenous retinal detachment repair].

Objective: To identify factors associated with persistent subretinal fluid (SRF) after scleral buckling and to evaluate surgical outcomes of patients with primary rhegmatogenous retinal detachment (RRD). Methods: Cross-sectional study and cohort study. This study included 104 patients (104 eyes) who underwent scleral buckling for repair of RRD between January 2016 and June 2017. Several statistically significant risk factors associated with SRF were screened out with univariate analysis. Then independent risk factors were determined with multivariate stepwise logistic regression analysis. Examinations were taken preoperatively, at 1, 3, 6, and 12 months postoperatively, and thereafter every six months. Patients were divided into two groups depending on the presence or absence of persistent SRF on optical coherence tomography at 1 month. Results: Persistent SRF occurred in 69.2% (72/104) of patients. In multivariate analysis, younger age (OR=32.860, 95%CI=3.636-296.986, P=0.002), high myopia (OR=7.229, 95%CI=1.217-42.94, P=0.03) and macula-involving retinal detachment (OR=357.397, 95%CI=29.761-4292.0, P=0.000) were associated with persistent SRF. Best corrected visual acuity in patients with SRF at 1 month (0.71±0.18 vs. 0.58±0.11; t=4.047, P<0.01) and 3 months (0.55±0.15 vs. 0.43±0.12; t=3.914, P<0.01) was worse than that in patients with absence of SRF. Best corrected visual acuity in patients with SRF was 0.44±0.16 at 6 months, 0.37±0.12 at 12 months and 0.36±0.10 at the last follow-up, with no significant difference from patients without SRF at the three time points (0.39±0.13, 0.38±0.12 and 0.35±0.09; t=1.643, -0.202, 0.464; P>0.05). Conclusions: RRD patients with younger age, high myopia and macular involvement were more likely to develop persistent SRF after scleral buckling. The presence of persistent SRF slowed visual recovery but did not influence the final visual outcomes. (Chin J Ophthalmol, 2021, 57: 426-432).

Effect of Mg/Ca molar ratios on characteristics of anaerobic-anoxic denitrifying dephosphatation.

In this study, the effect of three Mg/Ca molar ratios (5.0, 3.8 and 1.7) on denitrifying phosphate removal performance, biomass morphology, and Extracellular Polymeric Substances (EPS) were examined. Results showed that when the influent Mg/Ca molar ratio was 3.8, the anaerobic-anoxic EBPR performed complete phosphate removal. The microbial bacterial population was a mixed culture comprised of 81±3% DPAO and 13±2% denitrifying glycogen accumulating organisms (DGAO). A higher influent Mg/Ca molar ratio (5.0) had a distinct impact on phosphate removal, biomass morphology, and EPS. This probably induced the deterioration of the anaerobic-anoxic Enhanced Biological Phosphorus Removal (EBPR). The results of this study may inform the proper operation of an anaerobic-anoxic EBPR, and contribute to its application in the real world.

Laser-micromachined Fabry-Perot optical fiber tip sensor for high-resolution temperature-independent measurement of refractive index.

We propose and demonstrate a Fabry-Perot (F-P) optical fiber tip sensor for high-resolution refractive-index measurement fabricated by using 157-nm laser micromachining, for the first time to our knowledge. The sensor head consists of a short air F-P cavity near the tip of a single-mode fiber and the fiber tip. The external refractive index is determined according to the maximum fringe contrast of the interference fringes in the reflective spectrum of the sensor. Such a sensor can provide temperature-independent measurement of practically any refractive index larger than that of air and offers a refractive-index resolution of ~4 x 10(-5) in its linear operating range. The experimental data agree well with the theoretical results.

Miniature in-line photonic crystal fiber etalon fabricated by 157 nm laser micromachining.

A miniature in-line fiber-optic Fabry-Perot etalon is fabricated on a photonic crystal fiber (PCF) by using 157 nm laser micromachining for the first time to our knowledge. Experimental results show that such a PCF-based etalon has an excellent fringe visibility of up to approximately 26 dB due to the mirror-finish quality of the two cavity surfaces inside the PCF. This etalon can be used as an ideal sensor for precise strain measurement under high temperature of up to 800 degrees C. It can also offer some other outstanding advantages, such as fast and easy fabrication, high reproducibility, capacity of mass production, low cost, low temperature-strain cross-sensitivity, and high signal-to-noise ratio.

Fiber-optic Fabry-Perot sensors based on a combination of spatial-frequency division multiplexing and wavelength division multiplexing formed by chirped fiber Bragg grating pairs.

Effective multiplexing for a very large number of fiber-optic fiber-Bragg-grating-based Fabry-Perot (FBGFP) sensors is proposed that is based on wavelength division multiplexing (WDM) and spatial-frequency division multiplexing (SFDM). For WDM, FBGFP sensors are arranged in different wavelength domains formed by a series of chirped fiber Bragg gratings with different central wavelengths while the sensors with different cavity lengths within the same wavelength domain are multiplexed by use of SFDM because they have different spatial frequencies as a result of their different cavity lengths. In principle, a thousand FBGFP sensors could be multiplexed with such an approach. The experimental results show that a strain accuracy of better than +/-10 microepsilon has been achieved with little cross talk.