Derivation of new resistance principle on flow-induced morphological response of flexible vegetation.

Water flow under vegetated environments is a noteworthy research topic in environmental hydraulics and restoration ecology, and this research is particularly important for maintaining water transport and streambed stability in water ecosystems. The calculation of the resistance coefficient in vegetated water flow is the core of this research. But there are still problems such as complex expressions and low simulation accuracy in this research field. To solve this scientific problem, this research, based on the theoretical study of environmental hydraulics and genetic algorithm, selected three basic parameters of vegetation submergence, resistance length and curvature degree, and successfully constructed the formula for calculating the resistance coefficient for flexible vegetated flow by using a wide range of data sets. New quantitative relationship between the drag coefficient and the relative roughness of flexible vegetation was established in this study. The formula of drag coefficients for flexible vegetation conditions has a more concise form and can be successfully applied to both flexible and rigid vegetation. As flexible vegetation is deformed under the action of water flow, and the quantitative expressions of Vogel number and relative roughness are given quantitatively through the analysis of its physical properties. Overall, this study improves the basic theoretical study of vegetated flow in environmental fluid dynamics and provides scientific theoretical support for vegetation restoration.

Empirically derived dietary patterns and constipation among a middle-aged population from China, 2016-2018.

BACKGROUND: The association of dietary patterns with constipation is not well established, particularly in Chinese population. Therefore, the present study aimed to determine the relationship between dietary patterns and the risk of constipation in a middle-aged Chinese population. METHODS: A total of 2267 participants aged 45-59 years were recruited in Hangzhou city, the capital of Zhejiang Province, east China from August 2016 to October 2018. Dietary intake was estimated using a semi-quantitative food frequency questionnaire (FFQ) containing 138 food items. Constipation was defined using the Rome II criteria. Multivariate logistic regression was used to examine the association between dietary patterns and the risk of constipation. RESULTS: Three major dietary patterns were extracted by factor analysis and labeled as the traditional southern Chinese, Western and grains-vegetables patterns. The prevalence of constipation in our study population was 13.28%. Compared with the participants in the lowest quartile, the participants in the highest quartile of the traditional southern Chinese pattern were associated with reduced odds of constipation (odd ratios (OR) = 0.79; 95%confidence interval (CI): 0.626-0.981; P < 0.05), after adjusting for confounding variables. In contrast, we found no significant associations between the Western and grains-vegetables patterns and the risk of constipation (P > 0.05). CONCLUSIONS: Our study demonstrated that the traditional southern Chinese pattern was associated with a reduced risk of constipation. Further longitudinal studies are needed to confirm our findings.

Association of vitamin D receptor gene variants with polycystic ovary syndrome: a meta-analysis.

BACKGROUND: Polycystic ovary syndrome (PCOS) is a common endocrine disorder in reproductive-age women. Multiple susceptible gene as well as environmental factors and their interaction each other are contributed to the PCOS risk. Several case-control studies have researched the associations of the vitamin D receptor gene (VDR) polymorphisms with PCOS susceptibility, but the jury is still out. Here, we carried out a meta-analysis to clarify polymorphisms between ApaI (C/A) (rs7975232), BsmI (G/A) (rs1544410), FokI (C/T) (rs10735810), TaqI (T/C) (rs731236) and Tru9I (G/A) (rs757343) in the VDR gene and PCOS susceptibility based on relative lager sample size. METHODS: English database of PubMed and Embase, and Chinese database of Wanfang and China National Knowledge Infrastructure (CNKI) databases were retrivaled for the relationship between VDR gene variates and PCOS susceptibility published before 31th, May 2018. Crude odds ratios (ORs) and its 95% confidence intervals (95% CIs) in different comparisons were used to detected the strength of the association. All the statistical analyses of the present meta-analysis were performed by STATA version 12.0 software. RESULTS: Totally, 3587 (PCOS group 1922; control group 1665) participants from 13 studies were included which met our inclusion criteria. A statistically significant association between VDR ApaI (rs7975232) polymorphism and PCOS susceptibility (C vs. A: OR = 1.19, 95%CI = 1.06~1.34, P = 0.004) was found in the overall population. After stratified by ethnicity, we showed that there is a significant association between VDR ApaI (rs7975232) polymorphism and susceptibility to PCOS in the Asian (C vs. A: OR = 1.21, 95%CI = 1.04~1.42, P = 0.016) population, but this association was not found in the Caucasian population. Additionally, a significant relationship between VDR BsmI (rs1544410) variates with PCOS susceptibility in the Asian (G vs. A: OR = 1.27, 95%CI = 1.06~1.53, P = 0.011) population, but this association was not found in the Caucasian population. We didn't find any association between VDR FokI (rs2228570), VDR TaqI (rs731236), VDR Tru9I (rs757343) and PCOS susceptibility in the overall and the subgroup populations. CONCLUSIONS: Our findings demonstrated that VDR ApaI (rs7975232) and VDR BsmI (rs1544410) polymorphisms are correlated with susceptibility to PCOS in the Asian population and VDR TaqI (rs731236), VDR FokI (rs2228570), VDR Tru9I (rs757343) did not reveal a relationship with the PCOS susceptibility.

The feasibility of biodiesel production by microalgae using industrial wastewater.

This study investigated nitrogen and phosphorus assimilation and lipid production of microalgae in industrial wastewater. Two native strains of freshwater microalgae were evaluated their biomass growth and lipid production in modified BBM medium. Chlamydomonas sp. TAI-2 had better biomass growth and higher lipid production than Desmodesmus sp.TAI-1. The optimal growth and lipid accumulation of Chlamydomonas sp. TAI-2 were tested under different nitrogen sources, nitrogen and CO(2) concentrations and illumination period in modified BBM medium. The optimal CO(2) aeration was 5% for Chlamydomonas sp. TAI-2 to achieve maximal lipid accumulation under continuous illumination. Using industrial wastewater as the medium, Chlamydomonas sp. TAI-2 could remove 100% NH(4)(+)-N (38.4 mg/L) and NO(3)(-)-N (3.1mg/L) and 33% PO(4)(3-)-P (44.7 mg/L) and accumulate the lipid up to 18.4%. Over 90% of total fatty acids were 14:0, 16:0, 16:1, 18:1, and 18:3 fatty acids, which could be utilized for biodiesel production.