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Equipped with inter-satellite links (ISLs), BeiDou-3 satellites are able to operate autonomously in case of ground facility malfunction. To provide reliable positioning, navigation and timing service during autonomous operation, satellites need to maintain a stable time reference. In this letter, we propose a minimal covariance distributed Kalman filter (MCDKF) to realize distributed timekeeping. The proposed algorithm overcomes the problem of network dynamics. Meanwhile, it improves the stability of the on-board time reference by minimizing the variance of the estimate errors at each update step, under the constraint of local observations. Simulation results show that the proposed algorithm reduces the estimation variance and improves the frequency stability compared to other distributed algorithms.

Background: Hydraulic fracturing, a method used in Northeastern British Columbia (Canada) to extract natural gas, can release contaminants with potential deleterious health effects on fetal development. To date, the association between hydraulic fracturing activity and birth outcomes has not been evaluated in this region. Objective: To evaluate the association between the hydraulic fracturing well density/proximity and birth outcomes (birthweight, head circumference, preterm birth and small for gestational age (SGA)). Methods: We used birth records from the Fort St John hospital between December 30, 2006 and December 29, 2016 (n?=?6333 births). To estimate gestational exposure, we used inverse distance weighting (IDW) to calculate the density/proximity of hydraulic fracturing wells to pregnant women’s postal code centroid. For each birth, we calculated three IDWs using 2.5, 5, and 10?km buffer zones around women’s postal code centroid. We used linear and logistic regressions to evaluate associations between quartiles of postal code well density/proximity and birth outcomes, controlling for relevant covariates. Results: No associations were found between postal code well density/proximity and head circumference or SGA. A negative association was found between postal code well density/proximity and birthweight for infants born to women in the 2nd quartile of the 10?km buffer (ß [95% confidence interval (CI)]: -47.28?g [-84.30; -10.25]), and in the 2nd (ß [95% CI]: -40.87?g [-78.01; -3.73]) and 3rd (ß [95% CI]: -42.01?g [-79.15; -4.87]) quartiles of the 5?km buffer. Increased odds of preterm birth were observed among women in the 2nd quartile of the 2.5?km buffer (odds ratio (OR) [95% CI]: 1.60 [1.30; 2.43]). Conclusions: This is the first epidemiological study in Northeastern British Columbia evaluating associations between hydraulic fracturing and health outcomes. Our results show inconsistent patterns of association between hydraulic fracturing, preterm birth and reduced birthweight, and effect estimates did not match expected dose-response relationships.

China's accelerating development and increasingly important role in global health engagement create a great demand for global health professionals including international consulting experts. This study reported the detailed development and evaluation of an international consulting training for global health workforce.

An ultrasonic-assisted method for electroless Ni-P plating on dual-phase Mg-Li alloy is proposed. Environmentally-friendly Ce(NO3)3-KMnO4 solution was successfully applied for the pre-treatment. Uniform and compact Ni-P coatings with fine structures have been successfully obtained. The Ni-P coatings are mixed with amorphous-crystalline features and well adhered to the substrates. The corrosion resistances were investigated by electrochemical impedance spectroscopy, open circuit potential, potentiodynamic polarization and hydrogen evolution tests. The results indicate that ultrasonic processing significantly improves the corrosion resistance of Ni-P coatings due to the formation of uniform, dense and fine structures, which strengthen the passive film.

SAM pointed domain containing E26 transformation-specific transcription factor (SPDEF) plays dual roles in the initiation and development of human malignancies. However, the biological role of SPDEF in head and neck squamous cell carcinoma (HNSCC) remains unclear. In this study, the expression level of SPDEF and its correlation with the clinical parameters of patients with HNSCC were determined using TCGA-HNSC, GSE65858, and our own clinical cohorts. CCK8, colony formation, cell cycle analysis, and a xenograft tumor growth model were used to determine the molecular functions of SPDEF in HNSCC. ChIP-qPCR, dual luciferase reporter assay, and rescue experiments were conducted to explore the potential molecular mechanism of SPDEF in HNSCC. Compared with normal epithelial tissues, SPDEF was significantly downregulated in HNSCC tissues. Patients with HNSCC with low SPDEF mRNA levels exhibited poor clinical outcomes. Restoring SPDEF inhibited HNSCC cell viability and colony formation and induced G0/G1 cell cycle arrest, while silencing SPDEF promoted cell proliferation in vitro. The xenograft tumor growth model showed that tumors with SPDEF overexpression had slower growth rates, smaller volumes, and lower weights. SPDEF could directly bind to the promoter region of NR4A1 and promoted its transcription, inducing the suppression of AKT, MAPK, and NF-κB signaling pathways. Moreover, silencing NR4A1 blocked the suppressive effect of SPDEF in HNSCC cells. Here, we demonstrate that SPDEF acts as a tumor suppressor by transcriptionally activating NR4A1 in HNSCC. Our findings provide novel insights into the molecular mechanism of SPDEF in tumorigenesis and a novel potential therapeutic target for HNSCC.

An ultrasonic-assisted method for electroless Ni-P plating on dual-phase Mg-Li alloy is proposed. Environmentally-friendly Ce(NO3)3-KMnO4solution was successfully applied for the pre-treatment. Uniform and compact Ni-P coatings with fine structures have been successfully obtained. The Ni-P coatings are mixed with amorphous-crystalline features and well adhered to the substrates. The corrosion resistances were investigated by electrochemical impedance spectroscopy, open circuit potential, potentiodynamic polarization and hydrogen evolution tests. The results indicate that ultrasonic processing significantly improves the corrosion resistance of Ni-P coatings due to the formation of uniform, dense and fine structures, which strengthen the passive film.