High-Sensitivity Ultrasonic Guided Wave Monitoring of Pipe Defects Using Adaptive Principal Component Analysis.

Ultrasonic guided wave monitoring is regularly used for monitoring the structural health of industrial pipes, but small defects are difficult to identify owing to the influence of the environment and pipe structure on the guided wave signal. In this paper, a high-sensitivity monitoring algorithm based on adaptive principal component analysis (APCA) for defects of pipes is proposed, which calculates the sensitivity index of the signals and optimizes the process of selecting principal components in principal component analysis (PCA). Furthermore, we established a comprehensive damage index (K) by extracting the subspace features of signals to display the existence of defects intuitively. The damage monitoring algorithm was tested by the dataset collected from several pipe types, and the experimental results show that the APCA method can monitor the hole defect of 0.075% cross section loss ratio (SLR) on the straight pipe, 0.15% SLR on the spiral pipe, and 0.18% SLR on the bent pipe, which is superior to conventional methods such as optimal baseline subtraction (OBS) and average Euclidean distance (AED). The results of the damage index curve obtained by the algorithm clearly showed the change trend of defects; moreover, the contribution rate of the K index roughly showed the location of the defects.

Association of endometriosis with asthma: a study of the NHANES database in 1999-2006.

OBJECTIVE: Asthma is a chronic inflammatory disease of the airways with a gender differences in the prevalence after puberty. Recent studies have reported a relationship between asthma and endometriosis, possibly related to the immune response mechanisms, but the evidences are limited and inconsistent. Herein, this research aimed to investigate the association of endometriosis with asthma based on the representative population in the United States (U.S.) to provide some reference for further exploration on mechanism of gender difference in asthma. METHODS: In this cross-sectional study, data of women aged ≥ 20 years old were extracted from the National Health and Nutrition Examination Survey (NHANES) database in 1999-2006. Weighted univariate and multivariate logistic regression analyses were utilized to explore the association of endometriosis with asthma. The multivariate models adjusted for covariates including age, race, education level, marital status, poverty income ratio (PIR), body mass index (BMI), waist circumference, smoking, estrogen and progesterone hormones use, uterine fibroids, at least one ovary removed, and birth control pills intake. The evaluation indexes were odds ratios (ORs) and 95% confidence intervals (CIs). Subgroup analyses of age, race, BMI, and pregnancy history were also performed. RESULTS: Among 5,556 eligible women, 782 had asthma, and 380 had endometriosis. The average age of participants was 37.19 years old, and more than half of them were non-Hispanic White (68.44%). After adjusting for covariates, endometriosis was associated with higher odds of asthma compared with non-endometriosis [OR = 1.48, 95%CI: (1.10-1.99)]. This relationship was also found in 40-49 years old [OR = 2.26, 95%CI: (1.21-4.23)], BMI of 25-29.9 kg/m2 [OR = 2.87, 95%CI: (1.52-5.44)], and pregnancy history [OR = 1.44, 95%CI: (1.01-2.06)] subgroups. CONCLUSION: Endometriosis had a positive association with asthma in adult women. Females aged 40-49 years old, with BMI of 25-29.9 kg/m2 and had a history of pregnancy should take care about monitoring endometriosis to reduce the potential risk of asthma. Further studies are still needed to clarify the causal association between endometriosis and asthma.

Prediction value of plasma D-dimer level changes on venous thromboembolism during pregnancy.

OBJECTIVE: To explore the changes in plasma D-dimer (D-D) levels of pregnant women during pregnancy and their predictive value for venous thromboembolism (VTE). METHODS: A selection of 240 pregnant women who came to our hospital for routine perinatal care and delivery from January 2018 to January 2019 were selected as the observation group, and 240 cases that came to our hospital for routine physical examination were served as the control group. The D-D levels of the two groups of women were compared, and the D-D levels of pregnant women in the observation group with different delivery methods were explored; the observation group was into VTE and non-VTE groups according to the occurrence of VTE, and the D-D levels of the two groups of pregnant women in different periods were compared, and its predictive value on VTE was analyzed. RESULTS: The observation group exhibited a notably higher D-D level than the control group (p < .001), and the D-D level of the observation group during the first trimester was lower than the second and third trimesters, with statistical difference observed (p < .001), and the second trimester was much lower than the third trimester (p < .001); the D-D level in pregnant women with vaginal delivery showed lower level when comparing with women with cesarean section (p < .001); the D-D level of the VTE group was remarkably higher than that of the non-VTE group (p < .05); the D-D level during the second trimester had the highest predictive value for VTE, with the optimal cutoff value of 1.40 mg/L, the sensitivity of 69.3%, and the specificity of 76.7%, and AUC = 0.73. CONCLUSION: The D-D of pregnant women during pregnancy showed an increase trend with the gestational weeks, and they were all beyond the normal range. The D-D level in the second trimester has the highest predictive value for VTE.