[Assessing soil pH in Anhui Province based on different features mining methods combined with generalized boosted regression models]. / 基于不同特征挖掘方法结合广义提升回归模型估测安徽省土壤pH.

We explored the application of different feature mining methods combined with genera-lized boosted regression models in digital soil mapping. Environmental covariates were selected by two feature selection methods i.e., recursive feature elimination and selection by filtering. Using the original environmental covariates and the selected optimal variable combination as independent varia-bles, soil pH prediction model of Anhui Province was established and mapped based on the genera-lized boosted regression model and random forest model. The results showed that both kinds of feature mining methods could effectively improve the accuracy of soil pH prediction by generalized boosted regression models and random forest model, and could reduce dimensionality. Compared with the random forest model, the prediction accuracy of the validation set of the generalized boosted regression model was slightly lower. In the training set, the accuracy of the generalized boosted regression models was much higher than that of the random forest model, with higher interpretation and better overall effect. The main parameters of the random forest model, ntree and mtry, had limi-ted effect on the model. Different parameters and their combination could affect the prediction accuracy of the generalized boosted regression models, and thus should be tuned before modeling. The results of spatial mapping showed that soil pH in Anhui Province showed a pattern of "south acid and north alkali".

[Remote sensing monitoring and evaluation of spatial and temporal changes of ecological environment in Hangjin Banner, Inner Mongolia, China].

With the ecological environment problems being increasingly prominent and globalized, more and more attention is paid to environmental protection. Remote sensing technology is important in monitoring and evaluating ecological environment. In this study, based on the Landsat image data of 1992, 2000, 2008 and 2017, the remote sensing ecological index (RSEI) was constructed to monitor and evaluate the quality of ecological environment in Hangjin Banner, Inner Mongolia, aiming to provide a theoretical basis for local ecological environment protection. The results showed that from 1992 to 2017, the quality of ecological environment in Hangjin Banner was generally poor, with RESI grades of poor and inferior. The mean value of RESI increased from 0.31 (1992) to 0.37 (2008) and then decreased to 0.30 (2017). During the period, the change range was mainly from one grade to the next. In terms of spatial distribution, the regions with poor ecological environment quality were mainly in the desert plains of the central and western regions, that with good ecological quality mainly along the Yellow River and in the southeast, and that with large fluctuation of ecological quality grade mainly in the desert edge along the Yellow River and in the hilly and gully regions in the east. During the research period, the center of gravity of each ecological grade in Hangjin Banner substantially shifted, with spatiotemporal fluctuations. Our results suggest that ecological environment of Hangjin Banner was fragile and unstable. Ecological construction can promote the quality of ecological environment, but resources and land use should also be reasonably allocated.

Efficient two-step chemo-enzymatic synthesis of all-trans-retinyl palmitate with high substrate concentration and product yield.

A new two-step chemo-enzymatic approach for highly efficient synthesis of all-trans-retinyl palmitate is constructed in this study. In the first step, retinyl acetate as starting material was fully hydrolyzed to retinol by potassium hydroxide. In the hydrolysis system, anhydrous ethanol was the best co-solvent to increase the solubility of retinyl acetate. The addition amounts of 5 M potassium hydroxide and anhydrous ethanol were 8 and 10 mL against 10 g retinyl acetate, respectively, and 100 % hydrolysis rate was obtained. In the second step, esterification was catalyzed by immobilized lipase on macroporous acrylic resin AB-8 using the extracted retinol and palmitic acid as substrates in non-aqueous system. After optimization, the parameters of esterification reaction were confirmed as follows: non-aqueous solvent was selected as n-hexane, washing times of extraction solution was four times, retinol concentration was 300 g/L, substrate molar ratio of retinol to palmitic acid was 1:1.1, the amount of immobilized enzyme was 10 g/L, and the esterification temperature was 30 °C. Under the optimal conditions, this protocol resulted in a 97.5 % yield of all-trans-retinyl palmitate in 700-L reactor. After purification, all-trans-retinyl palmitate was obtained with above 99 % of purity and 88 % of total recovery rate. This methodology provides a promising strategy for the large-scale production of all-trans-retinyl palmitate.

Effect of conjugated linoleic acid on blood pressure: a meta-analysis of randomized, double-blind placebo-controlled trials.

BACKGROUND: Numerous studies on animals evidenced that conjugated linoleic acid (CLA) could decrease blood pressure (BP) in several rat models. However, such beneficial effect is not completely supported by studies on humans. METHODS: We searched the Pubmed, Cochrane Library, and the ClinicalTrials.gov databases for relevant randomized, double-blind placebo-controlled trials up to August 2014 to perform a meta-analysis. A random-effects model was used to calculate the combined treatment effects. RESULTS: Eight studies with nine trials, which involved 638 participants with CLA supplementation ranging from 2.0 g/day to 6.8 g/day, were included in this meta-analysis. Compared with placebo, the pooled estimate of change was -0.03 mm Hg (95% CI: -2.29, 2.24, P=0.98) and 0.69 mm Hg (95% CI: -1.41, 2.80, P=0.52) in systolic and diastolic BPs, respectively. No significant heterogeneity across studies for systolic BP; however, substantial heterogeneity for diastolic BP was identified. Publication bias was not found for both systolic and diastolic BPs. CONCLUSION: The findings of this meta-analysis did not support the overall favorable effect of CLA supplementation on BP regulation.

Effect of whey supplementation on circulating C-reactive protein: a meta-analysis of randomized controlled trials.

Whey supplementation is beneficial for human health, possibly by reducing the circulating C-reactive protein (CRP) level, a sensitive marker of inflammation. Thus, a meta-analysis of randomized controlled trials was conducted to evaluate their relationship. A systematic literature search was conducted in July, 2014, to identify eligible studies. Either a fixed-effects model or a random-effects model was used to calculate pooled effects. The meta-analysis results of nine trials showed a slight, but no significant, reduction of 0.42 mg/L (95% CI -0.96, 0.13) in CRP level with the supplementation of whey protein and its derivates. Relatively high heterogeneity across studies was observed. Subgroup analyses showed that whey significantly lowered CRP by 0.72 mg/L (95% CI -0.97, -0.47) among trials with a daily whey dose≥20 g/day and by 0.67 mg/L (95% CI -1.21, -0.14) among trials with baseline CRP≥3 mg/L. Meta-regression analysis revealed that the baseline CRP level was a potential effect modifier of whey supplementation in reducing CRP. In conclusion, our meta-analysis did not find sufficient evidence that whey and its derivates elicited a beneficial effect in reducing circulating CRP. However, they may significantly reduce CRP among participants with highly supplemental doses or increased baseline CRP levels.

[Determination of trace elements in Chinese traditional medicines by atomic absorption spectrometry].

The 9 kinds of Chinese traditional medicines which are used to cure diabetes including Xiaokewan, Yuquanwan, Kelening, Jiangtangshu, Jiangtang I-V are digested with HNO3-HClO4 (4:1) mixed acid. The 12 trace elements of copper, zinc, nickel, cobalt, manganese, chromium, molybdenum, iron, calcium, magnesium, cadmium and lead in the solution are determined by atomic absorption spectrometry. Its recovery ratio by standard addition is 97%-105%, and RSD is lower than 5%. This method has good accurate. The results obtained show that except Cd and Pb all other ten trace elements contents in the drug are high. The results of this paper provide useful data for studying the relation between the contents of these trace elements and the medical effect.