Quantifying the Contribution of the Dispersion Interaction and Hydrogen Bonding to the Anisotropic Elastic Properties of Chitin and Chitosan.

The elastic tensors of chitin and chitosan allomorphs were calculated using density functional theory (DFT) with and without the dispersion correction and compared with experimental values. The longitudinal Young's moduli were 114.9 or 126.9 GPa for α-chitin depending on the hydrogen bond pattern: 129.0 GPa for ß-chitin and 191.5 GPa for chitosan. Furthermore, the moduli were found to vary between 17.0 and 52.8 GPa in the transverse directions and between 2.2 and 15.2 GPa in shear. Switching off the dispersion correction led to a decrease in modulus by up to 63%, depending on the direction. The transverse Young's moduli of α-chitin strongly depended on the hydroxylmethyl group conformation coupled with the dispersion correction, suggesting a synergy between hydrogen bonding and dispersion interactions. The calculated longitudinal Young's moduli were, in general, higher than experimental values obtained in static conditions, and the Poisson's ratios were lower than experimental values obtained in static conditions.

A Novel Remote Sensing Image Registration Algorithm Based on Feature Using ProbNet-RANSAC.

Image registration based on feature is a commonly used approach due to its robustness in complex geometric deformation and larger gray difference. However, in practical application, due to the effect of various noises, occlusions, shadows, gray differences, and even changes of image contents, the corresponding feature point set may be contaminated, which may degrade the accuracy of the transformation model estimate based on Random Sample Consensus (RANSAC). In this work, we proposed a semi-automated method to create the image registration training data, which greatly reduced the workload of labeling and made it possible to train a deep neural network. In addition, for the model estimation based on RANSAC, we determined the process according to a probabilistic perspective and presented a formulation of RANSAC with the learned guidance of hypothesis sampling. At the same time, a deep convolutional neural network of ProbNet was built to generate a sampling probability of corresponding feature points, which were then used to guide the sampling of a minimum set of RANSAC to acquire a more accurate estimation model. To illustrate the effectiveness and advantages of the proposed method, qualitative and quantitative experiments are conducted. In the qualitative experiment, the effectiveness of the proposed method was illustrated by a checkerboard visualization of image pairs before and after being registered by the proposed method. In the quantitative experiment, other three representative and popular methods of vanilla RANSAC, LMeds-RANSAC, and ProSAC-RANSAC were compared, and seven different measures were introduced to comprehensively evaluate the performance of the proposed method. The quantitative experimental result showed that the proposed method had better performance than the other methods. Furthermore, with the integration of the model estimation of the image registration into the deep-learning framework, it was possible to jointly optimize all the processes of image registration via end-to-end learning to further improve the accuracy of image registration.

Outbreak of mumps in a student population with high vaccination coverage in China: time for two-dose vaccination.

In 2016, an outbreak of mumps occurred in a primary school in China with a student population having high vaccination coverage. An unmatched case-control study was performed to identify risk factors contributing to this outbreak, and a retrospective cohort study was conducted to evaluate the effectiveness of mumps-containing vaccine (MuCV). A total of 97 cases were identified during the outbreak, and the overall attack rate was 8.2%. Among students with confirmed vaccination status, 90% had received at least one dose of MuCV. Cases were more likely than non-cases to report taking the school bus during the epidemic period (adjusted OR = 2.3, 95% CI: 1.4-3.7). Vaccine effectiveness (VE) was higher for two-dose MuCV (76%, 95% CI:49â€"89%) than for one-dose MuCV (59%, 95% CI: 36â€"74%. The protection afforded by both one-dose and two-dose MuCV waned over time, from 82% among students vaccinated within 5 years to 41% among those vaccinated more than 10 years previously for one-dose VE, and from 90% to 25% over the same time period for two-dose VE. We found that outbreaks of mumps can occur in schools despite high coverage of one-dose MuCV vaccination. Although the VE of both two-dose and one-dose MuCV wanes over time, the overall VE for two-dose MuCV was superior than that of one-dose MuCV. Therefore, a two-dose MuCV schedule through routine services is likely needed in order to control mumps epidemics in China.

Association between Insulin Resistance, Metabolic Syndrome and Nonalcoholic Fatty Liver Disease in Chinese Adults.

BACKGROUND: The aim of this study was to assess the association between insulin resistance, metabolic syndrome and nonalcoholic fatty liver disease (NAFLD) in Chinese adults. METHODS: Fifty five subjects with NAFLD and 55 controls were enrolled for the study. Waist circumference, blood pressure, plasma triglyceride, high density lipoprotein cholesterol and fasting plasma glucose concentrations and homeostasis model assessment of insulin resistance (HOMA-IR) values as an index used to quantify insulin resistance were measured and analyzed. Logistic regression was analyzed to predict independent risk factors of NAFLD. RESULTS: The prevalence of metabolic syndrome in NAFLD group was obviously higher than in controls group (47.3% VS 3.6%, P<0.001). There were all significant differences of each component of metabolic syndrome and HOMA-IR values in comparison of nonalcoholic fatty liver disease (NAFLD) and controls group. In a logistic regression analysis, age, diastolic blood pressure, waist circumference and HOMA-IR were the covariates independently associated with the presence of NAFLD (Odds Ratio=1.107, 1.083, 1.218 and 16.836; 95% CI: 1.011∼1.211, 1.001∼1.173, 1.083∼1.370 and 3.626∼78.168, respectively; P<0.05) CONCLUSION: NAFLD was closely associated with metabolic syndrome and insulin resistance was a very strong predictor of NAFLD.

Association of the apolipoprotein B/apolipoprotein A-I ratio and low-density lipoprotein cholesterol with insulin resistance in a Chinese population with abdominal obesity.

The aim of this study is to assess the relationships among the apolipoprotein B/apolipoprotein A-I ratio (apoB/apoA-I ratio), low-density lipoprotein cholesterol (LDL-C) and insulin resistance (IR) in a Chinese population with abdominal obesity. This is a population-based, cross-sectional study of 3,945 men and 2,141 women with abdominal obesity. Individuals were referred to a primary health service and recruited for analysis. IR was measured using a homeostasis model assessment of insulin resistance (HOMA2-IR) with a HOMA2 calculator. Metabolic syndrome (MetS) was diagnosed using International Diabetes Federation (IDF) criteria. Comparing the apoB/apoA-I ratio and lipid indices using the HOMA2-IR showed that the ratio, LDL-C, total cholesterol level (TC) and triglyceride level (TG) were higher; and the high-density lipoprotein cholesterol level (HDL-C) was lower in the fourth than in the first quartile in both sexes (p ≤ 0.001). After adjustment for age, HOMA2-IR was positively correlated with the apoB/apoA-I ratio, LDL-C, TC and TG; and negatively correlated with HDL-C in men (all p < 0.0001). HOMA2-IR was also positively correlated with the apoB/apoA-I ratio, LDL-C, TC and TG; and negatively correlated with HDL-C in women (all p < 0.01). After adjustment for age and LDL-C, HOMA2-IR was found to be correlated with the apoB/apoA-I ratio in both men and women (r = 0.066 and 0.116, p < 0.0001). After adjustment for age and the apoB/apoA-I ratio, HOMA2-IR was correlated with LDL-C in men and women (r = 0.063 and 0.044, p < 0.0001 and p = 0.0431, respectively). Gender, age, LDL-C, BMI, HOMA2-IR and apoB/apoA-I were the covariates independently associated with presence of the MetS (Odds ratio, OR: 2.183, 1.034, 1.013, 1.157, 1.726 and 1.570, respectively; all p < 0.05). In conclusion, the study showed that the apoB/apoA-I ratio and LDL-C were positively correlated with IR. Excluding reciprocal interactions, the apoB/apoA-I ratio and LDL-C were still significantly correlated with IR, but the apoB/apoA-I ratio showed a greater correlation with IR than LDL-C in women with abdominal obesity, compared with men with abdominal obesity. Both LDL-C and apoB/apoA-I were independent risk factors of MetS, and the apoB/apoA-I ratio was stronger in this regard than LDL-C for this obese population.

Body mass index, waist circumference, and cardiometabolic risk factors in young and middle-aged Chinese women.

OBJECTIVE: To assess the associations between body mass index (BMI), waist circumference (WC), and cardiometabolic risk factors in young and middle-aged Chinese women. METHODS: A total of 3011 women (1938 young women, 1073 middle-aged women), who visited our health care center for a related health checkup, were eligible for study. BMI and WC were measured. The subjects were divided into normal and overweight/obesity groups based on BMI, and normal and abdominal obesity groups based on WC. Cardiometabolic variables included triglyceride (TG), high density lipoprotein cholesterol (HDL-C), fasting blood glucose (FBG), homeostasis model assessment of insulin resistance (HOMA-IR), and blood pressure (BP). RESULTS: The prevalence of overweight/obesity was significantly higher in middle-aged women (32.4%) than in young women (12.0%). The prevalence of abdominal obesity was also higher in middle-aged women (60.3%) than in young women (36.2%). There were significant differences in the comparison of all related cardiometabolic variables between different BMI (or WC) categories in young and middle- aged women groups, respectively. After adjustment for age, partial correlation analysis indicated that both BMI and WC were correlated significantly with all related cardiometabolic variables. After adjustment for age and WC, although the correlation coefficient r' was attenuated, BMI was still correlated significantly with all related cardiometabolic variables in young and middle-aged women. After adjustment for age and BMI, partial correlation analysis showed that WC was correlated significantly with TG, FBG, HOMA-IR, and HDL-C in young women and significantly with TG, HOMA-IR, and HDL-C in middle-aged women. CONCLUSIONS: The prevalence of overweight/obesity and abdominal obesity was high in Chinese young and middle-aged women. BMI was a better predictor of cardiovascular disease and diabetes than WC in young and middle-aged women, and moreover, measurement of both WC and BMI may be a better predictor of cardiovascular disease and diabetes mellitus than BMI or WC alone.