RESUMO
Objective: Neonatal hypoglycemia is a severe adverse consequence of infants born to mothers with gestational diabetes mellitus (GDM), which can lead to neonatal mortality, permanent neurological consequences, and epilepsy. This systematic review and meta-analysis of randomized controlled trials (RCTs) was conducted to explore the effect of lifestyle intervention during pregnancy in women with GDM on the risk of neonatal hypoglycemia. Methods: PubMed, Web of Science, Cochrane Library, CINAHL, and SPORTDiscus databases were searched by 1st April 2022. Data were pooled as the risk ratio (RR) with 95% CIs of neonatal hypoglycemia. Random-effects, subgroup analyses, meta-regression analysis, and leave-one-out analysis were conducted, involving 18 RCTs. Results: Prenatal lifestyle intervention could significantly reduce the risk of neonatal hypoglycemia (RR: 0.73, 95% CI: 0.54-0.98, P = 0.037). Subgroup analysis further demonstrated that the reduced risk of neonatal hypoglycemia was observed only when subjects were younger than 30 years, initiated before the third trimester, and with dietary intervention. Meta-regression analysis revealed that the risk of neonatal hypoglycemia post lifestyle intervention was lower in mothers with lower fasting glucose levels at trial entry. Conclusion: We found that prenatal lifestyle intervention in women with GDM significantly reduced the risk of neonatal hypoglycemia. Only lifestyle intervention before the third trimester of pregnancy, or dietary intervention only could effectively reduce the risk of neonatal hypoglycemia. Future studies are required to explore the best pattern of lifestyle intervention and to determine the proper diagnostic criteria of GDM in the first/second trimester of pregnancy. Systematic review registration: https://www.crd.york.ac.uk/PROSPERO/#myprospero, PROSPERO, identifier: CRD42021272985.
RESUMO
We propose a novel fiber-optic Fabry-Perot interferometric (FFPI) temperature sensor based on differential pressure resulting from thermal expansion of sealed air. A thin silicon diaphragm is sandwiched between two micro-circular cavity-structured Pyrex plates to construct a FP and an air cavity. The thermal expansion of sealed air induces differential pressure variation between cavities and thus the deformation of thin diaphragm, which transfers temperature change into cavity length shift of FP interferometer. Theory analysis results indicate that the temperature-sensitivity can be designed flexibly by choosing the parameters of radius and thickness of silicon diaphragm, and the differential pressure between two cavities. Experimental results demonstrate that the temperature sensitivity of 6.07 nm/°C is achieved with the resolution of 0.10°C under the range of -50°C to 100°C, and the response time is around 1.3 s with temperature change from 28°C to 100°C.
RESUMO
We present a high precision and fast speed demodulation method for a polarized low-coherence interferometer with location-dependent birefringence dispersion. Based on the characteristics of location-dependent birefringence dispersion and five-step phase-shifting technology, the method accurately retrieves the peak position of zero-fringe at the central wavelength, which avoids the fringe order ambiguity. The method processes data only in the spatial domain and reduces the computational load greatly. We successfully demonstrated the effectiveness of the proposed method in an optical fiber Fabry-Perot barometric pressure sensing experiment system. Measurement precision of 0.091 kPa was realized in the pressure range of 160 kPa, and computation time was improved by 10 times compared to the traditional phase-based method that requires Fourier transform operation.
