Hybrid fiber-based time synchronization and vibration detection system.

We propose a hybrid fiber-based time synchronization and vibration detection system. The vibration is detected by exploring the idle light of the time synchronization system, i.e., the Rayleigh backscattering of the timing pulse disseminated in the fiber link. The addition of a sensing function does not affect the performance of time synchronization. In the multiuser experimental demonstration, time deviation results are 3.6 ps at τ = 1 s and 1.4 ps at τ = 104 s on the 40-km fiber link. Meanwhile, the hybrid system can accurately detect and locate vibrations occurring on the link. This method enables multiple functions of the optical fiber network without occupying extra optical channels. Moreover, it gives a possible solution for enhancing the security of the time synchronization network through vibration detection.

Intradialytic BP variability is associated with cardiovascular mortality and hospitalization in HD patients.

INTRODUCTION: Studies showed that pre-dialysis BP variability (BPV) was an independent risk factor of cardiovascular disease (CVD) among HD patients, but which is limited on how intradialytic BPV affects prognosis. METHODS: In this study, we designed a retrospective cohort study to examine the association between intradialytic BPV and CVD outcomes in HD patients. A total of 202 patients who underwent HD in our center were included, and all intradialytic BP measurements of November 2017 were obtained from the database. Patients were divided into four groups according to variability independent of the mean (VIM) interquartile. RESULTS: The mean age was 62.1 ± 14.3 years, 60.9% were male, and median VIM was 14.75 (12.60-18.59). Multiple-regression analyses showed patients age, dialysis vintage, serum albumin, and the percentage of intradialytic weight gain as significant predictors of VIM (all p values were <0.05). Kaplan-Meier survival curves showed that CVD mortality was greater in patients with higher VIM (p = 0.05), whereas all-cause mortality had no significant difference between the four groups overall (p = 0.149). Furthermore, multivariate regression analyses demonstrated that VIM (HR = 1.091, p < 0.004) and age (HR = 1.059, p = 0.003) were significant independent predictors for CVD death. Logistic-regression models revealed that higher VIM groups were more likely to have CVD-related hospitalization (OR = 1.085, p = 0.030), whereas the association between VIM and all-cause hospitalization was not statistically significant (OR = 1.015, p = 0.669). CONCLUSIONS: This retrospective study suggested that higher intradialytic BPV was associated with increasing age, longer dialysis vintage, lower albumin, and greater ultrafiltration; intradialytic BPV could be an effective predictor for CVD mortality and hospitalization in the HD population.