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Structural health monitoring (SHM) is vital to the maintenance of civil infrastructures. For rail transit systems, early defect detection of rail tracks can effectively prevent the occurrence of severe accidents like derailment. Non-destructive testing (NDT) has been implemented in railway online and offline monitoring systems using state-of-the-art sensing technologies. Data-driven methodologies, especially machine learning, have contributed significantly to modern NDT approaches. In this paper, an efficient and robust image classification model is proposed to achieve railway status identification using ultrasonic guided waves (UGWs). Experimental studies are conducted using a hybrid sensing system consisting of a lead–zirconate–titanate (PZT) actuator and fiber Bragg grating (FBG) sensors. Comparative studies have been firstly carried out to evaluate the performance of the UGW signals obtained by FBG sensors and high-resolution acoustic emission (AE) sensors. Three different rail web conditions are considered in this research, where the rail is: (1) intact without any defect; (2) damaged with an artificial crack; and (3) damaged with a bump on the surface made of blu-tack adhesives. The signals acquired by FBG sensors and AE sensors are compared in time and frequency domains. Then the research focuses on damage detection using a convolutional neural network (CNN) with the input of RGB spectrum images of the UGW signals acquired by FBG sensors, which are calculated using Short-time Fourier Transform (STFT). The proposed image classifier achieves high accuracy in predicting each railway condition. The visualization of the classifier indicates the high efficiency of the proposed paradigm, revealing the potential of the method to be applied to mass railway monitoring systems in the future.

The aerodynamic characteristics of air-breathing combined power flight vehicle change drastically with flight conditions during wide envelope. Using traditional trajectory optimization methods based on aerodynamic linear interpolation model, results show that the control variables and state variables change greatly with poor smoothness, which cannot meet working conditions of air-breathing dynamic model and make it difficult for control system design. In this paper, based on Hp adaptive pseudospectral method, the response surface surrogate model is put forward to gain smooth aerodynamic data, solving problems in the aerodynamic linear interpolation model. Results of ascent trajectory optimization of the Rocket-Based Combined Cycle power flight vehicle show that the angle of attack control changes smoothly and has small absolute value of the first derivative during the flight, and trajectory is relatively smooth, which provides ideal working condition for engine. Meanwhile, trajectory simulation using obtained optimal control variable is achieved, which shows small difference and further verifies the feasibility of the aerodynamic surrogate model.

Free to read Background - Little is known about the relation between vitamin D status in early life and neurodevelopment outcomes. Objective - This study was designed to examine the association of cord blood 25-hydroxyvitamin D [25(OH)D] at birth with neurocognitive development in toddlers. Methods - As part of the China-Anhui Birth Cohort Study, 363 mother-infant pairs with completed data were selected. Concentrations of 25(OH)D in cord blood were measured by radioimmunoassay. Mental development index (MDI) and psychomotor development index (PDI) in toddlers were assessed at age 16–18 mo by using the Bayley Scales of Infant Development. The data on maternal sociodemographic characteristics and other confounding factors were also prospectively collected. Results - Toddlers in the lowest quintile of cord blood 25(OH)D exhibited a deficit of 7.60 (95% CI: −12.4, −2.82; P = 0.002) and 8.04 (95% CI: −12.9, −3.11; P = 0.001) points in the MDI and PDI scores, respectively, compared with the reference category. Unexpectedly, toddlers in the highest quintile of cord blood 25(OH)D also had a significant deficit of 12.3 (95% CI: −17.9, −6.67; P < 0.001) points in PDI scores compared with the reference category. Conclusions - This prospective study suggested that there was an inverted-U–shaped relation between neonatal vitamin D status and neurocognitive development in toddlers. Additional studies on the optimal 25(OH)D concentrations in early life are needed.

Portland cement, silica fume, superplasticizer and fly ash cemamsite were used to obtain a high strength lightweight aggregate concrete with lower water to binder ratio. An enhancement effect on the strength was gained by adding steel fiber. When the expansive agent added with the steel fiber a synergistic reinforcing effect on the compressive strength, tensile strength and bending strength was obtained because of more energy consumed to pull the fibers out under the different loads.

In this paper, a novel GPS (Global Positioning System) and DR (Dead Reckoning) system which is based on the accelerometer and gyroscope integrated system is designed and implemented, a new accelerometer calibration algorithm is also proposed. In this system, the odometer used in traditional DR system is replaced by a MEMS tri-axis accelerometer in order to decrease the cost and the volume of the system. The system is integrated by the Kalman filter and a new mathematical model is introduced. In the purpose of reducing the effect of the accumulated error caused by drift and bias of accelerometer, the accelerometer is calibrated online when GPS performs well. In this way, the integrated system does not only could obtain the high-precision positioning in real time, but also performs stably in practice.

We aimed to investigate whether the newborns of mothers with maternal depression (MD) had lower vitamin D levels than newborns of non-MD (NMD) mothers and identify the potential mechanism underlying this association. Maternal depressive symptoms in late pregnancy and concentrations of cord blood 25 hydroxyvitamin D (25(OH)D) were measured in 1491 mother-infant pairs. Data on maternal sociodemographic characteristics, health status, lifestyle and birth outcomes were prospectively collected. For infants born in winter-spring, the infants of MD mothers had significantly reduced concentrations of 25(OH) D (adjusted β = −3.51 nmol/L; 95% CI: −6.19, −0.84; P = 0.010) and lower birth weight (3267 ± 470 g vs 3348 ± 598 g, F = 4.64, P = 0.031), compared with the infants of NMD mothers. A significant, inverse linear relationship was noted between maternal depression scores and the concentration of 25(OH)D for infants born in winter-spring (adjusted β = −0.158; 95% CI: −0.259, −0.057). The significant, inverse linear relationship between maternal depression scores and fetomaternal ratios of 25(OH) D was also observed among the infants born in winter-spring (adjusted β = −0.005; 95% CI: −0.008, −0.003). MD appears to significantly attenuate the vitamin D concentrations and birth weight of infants born in winter-spring. A decreased fetomaternal ratio of 25(OH)D might be involved in this biological pathway.

Pedestrian Navigation System (PNS) is a system aims at determining the current location of person, recording the walking trajectory. This paper presents an algorithm of PNS based on lowperformance MEMS-IMU attaching to the waist of people. The algorithm consists of step detection, model identification, stride, heading determination and position estimation. A method to identify a user’s status, calibrate the length coefficient K by Least-Squares and update K online according to different models and acceleration is presented, which adaptively adjusts the calculation of stride length in case of different walking speeds and manners. The integration of INS and magnetic azimuth for heading direction is put forward and the walking trajectory is calculated by Dead Reckoning (DR). Several tests have been conducted and the algorithm performed well.

In the case that the accuracy of standard kalman filter (SKF) declines when the noise statistical characteristics are unknown or changing, a measurement-based adaptive kalman filtering algorithm (MAKF) is presented. Based on the contrastive analysis of measurement characteristics of different measurement systems, MAKF is put forward to estimate adaptively the measurement noise variance R by co-difference measurement sequences. Simulation is performed by applying this algorithm to the GPS/INS integrated navigation system, the results show that MAKF can track the GPS measurement noise in real time on condition that the GPS measurement noise is unknown or changing, and the filtering accuracy and robustness are superior to those of SKF and an improved Sage-Husa adaptive kalman filtering algorithm.

Some studies suggested that adequate vitamin D might reduce inflammation in adults. However, little is known about this association in early life. We aimed to determine the relationship between cord blood 25-hydroxyvitamin D (25(OH)D) and C-reactive protein (CRP) in neonates. Cord blood levels of 25(OH)D and CRP were measured in 1491 neonates in Hefei, China. Potential confounders including maternal sociodemographic characteristics, perinatal health status, lifestyle, and birth outcomes were prospectively collected. The average values of cord blood 25(OH)D and CRP were 39.43 nmol/L (SD = 20.35) and 6.71 mg/L (SD = 3.07), respectively. Stratified by 25(OH)D levels, per 10 nmol/L increase in 25(OH)D, CRP decreased by 1.42 mg/L (95% CI: 0.90, 1.95) among neonates with 25(OH)D &lt, 25.0 nmol/L, and decreased by 0.49 mg/L (95% CI: 0.17, 0.80) among neonates with 25(OH)D between 25.0 nmol/L and 49.9 nmol/L, after adjusting for potential confounders. However, no significant association between 25(OH)D and CRP was observed among neonates with 25(OH)D ≥50 nmol/L. Cord blood 25(OH)D and CRP levels showed a significant seasonal trend with lower 25(OH)D and higher CRP during winter-spring than summer-autumn. Stratified by season, a significant linear association of 25(OH)D with CRP was observed in neonates born in winter-spring (adjusted β = −0.11, 95% CI: −0.13, −0.10), but not summer-autumn. Among neonates born in winter-spring, neonates with 25(OH)D &lt, 25 nmol/L had higher risk of CRP ≥10 mg/L (adjusted OR = 3.06, 95% CI: 2.00, 4.69), compared to neonates with 25(OH)D ≥25 nmol/L. Neonates with vitamin D deficiency had higher risk of exposure to elevated inflammation at birth.

We determined the association of cord blood 25-hydroxyvitamin D [25(OH)D] with birth weight and the risk of small for gestational age (SGA). As part of the China-Anhui Birth Cohort (C-ABC) study, we measured cord blood levels of 25(OH)D in 1491 neonates in Hefei, China. The data on maternal sociodemographic characteristics, health status, lifestyle, birth outcomes were prospectively collected. Multiple regression models were used to estimate the association of 25(OH)D levels with birth weight and the risk of SGA. Compared with neonates in the lowest decile of cord blood 25(OH)D levels, neonates in four deciles (the fourth, fifth, sixth and seventh deciles) had significantly increased birth weight and decreased risk of SGA. Multiple linear regression models showed that per 10 nmol/L increase in cord blood 25(OH)D, birth weight increased by 61.0 g (95% CI: 31.9, 89.9) at concentrations less than 40 nmol/L and then decreased by 68.5 g (95% CI: −110.5, −26.6) at concentrations from 40 to 70 nmol/L. This study provides the first epidemiological evidence that there was an inverted U shaped relationship between neonatal vitamin D status and fetal growth and the risk of SGA reduced at moderate concentration.

Transforming growth factor-β is an important cytokine with various bioactivities, including embryonic development, wound healing, chemotaxis and cell cycle regulation. Epithelial-mesenchymal transition (EMT) is the main pathway of tumor cell to obtain the ability of invasion and metastasis. The TGF-β is the key factor known to induce EMT in cancer cells and plays an important role in the process. In recent years, some progress has been obtained. Some TGF-β inhibitors have approved in the market or in clinical trials. TGF-β inhibitors can play an important role on the treatment of tumors, glaucoma, liver and kidney fibrosis disease and scar repair. Novel TGF-β inhibitors reported in recent years were reviewed in this article.