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A high precision demodulation method based on least squares fitting for expanding the temperature measurement range of the fiber Lyot filter has been proposed and experimentally demonstrated. And a compact reflective Lyot filter has also been proposed to verify this method. The filter consists of a polarizer and a section of polarization maintaining fiber (PMF) coated with a gold film at the end. The birefringence of the PMF can be obtained through the least squares method, so that the temperature measurement range is not limited to the free spectral range (FSR) of the periodic interference spectrum. Experimental results show that the proposed method can extend the measurement range by 5.5 times compared to the dip wavelength tracking method. And the demodulation fluctuation of the birefringence is within 10-7. INDEX TERMS Demodulation, fiber Lyot filter, polarization interference, temperature measurement.

Background Family caregivers play crucial roles in the self-management of patients with heart failure (HF). However, little is known about caregiving experiences of Chinese family caregivers during acute HF. Objective The aim of this study was to describe Chinese family caregivers' experiences in symptom management and care-seeking during acute HF. Methods This is an exploratory, qualitative study using the Consolidated Criteria for Reporting Qualitative Research guidelines. Data were collected through semistructured interviews and analyzed with thematic analysis. Findings A total of 21 family caregivers of patients with acute HF were enrolled in this study. “Empowered but isolated” was identified as the overarching theme during data analysis, including 3 themes and 6 subthemes: (1) “Responsible symptom managers: leading the home-based symptom management,” including 2 subthemes, “Proxy in symptom management” and “Only knowing the surface, instead of the truth”; (2) “Powerless anchors: care-seeking is a torturous journey,” including 2 subthemes, “Facing discrepancies in care-seeking” and “Seeing a doctor is the last choice”; (3) “Carrying the weight forward: responsibility combing with emotional burnout,” including 2 subthemes, “Living on tenterhooks” and “Submitting to fate.” Conclusions In this study, we described Chinese family caregivers' experiences in symptom management and care-seeking during acute HF. Although empowered as proxy, they were also isolated bearing a great burden, receiving insufficient support from patients, family, and the medical system.

A reflective cascaded structure with a fiber Lyot filter and a Fabry–Pérot interferometer has been proposed and experimentally demonstrated for ultra-highly temperature measurement. The sensitivity of the sensor can be magnified to −31.4 nm °C−1 based on the Vernier effect, to our knowledge, which is the highest among all-fiber structures without other assisted coating or filling materials. The sensor possesses the remote sensing capability. Furthermore, the initial state can be tuned by loading strains on the Fabry–Perot cavity, so that the maximum sensing range is available at different initial temperatures, and then allowing the sensor to fulfill more practical application needs.