Spatiotemporal evolution of dissolved organic matter (DOM) and its response to environmental factors and human activities.

The South-to-North Water Diversion East Project (SNWDP-E) is an effective way to realize the optimal allocation of water resources in China. The North Dasha River (NDR) is the reverse recharge section that receives water from the Yufu River to the Wohushan Reservoir transfer project line in the SNWDP. However, the dissolved organic matter (DOM) evolution mechanism of seasonal water transfer projects on tributary waters has not been fully elucidated. In this paper, the NDR is the main object, and the changes in the composition and distribution of spectral characteristics during the winter water transfer period (WT) as well as during the summer non-water transfer period (NWT) are investigated by parallel factor analysis (PARAFAC). The results showed that the water connectivity caused by water transfer reduces the environmental heterogeneity of waters in the basin, as evidenced by the ammonia nitrogen (NH4+-N) and total phosphorus (TP) in the water body were significantly lower (p<0.05, p<0.01) during the water transfer period than the non-water transfer period. In addition, the fluorescence intensity of DOM was significantly lower in the WT than the NWT (p<0.05) and was mainly composed of humic substances generated from endogenous sources with high stability. While the NWT was disturbed by anthropogenic activities leading to significant differences in DOM composition in different functional areas. Based on the redundancy analysis (RDA) and multiple regression analysis, it was found that the evolution of the protein-like components is dominated by chemical oxygen demand (COD) and NH4+-N factors during the WT. While the NWT is mainly dominated by total nitrogen (TN) and TP factors for the evolution of the humic-like components. This study helps to elucidate the impact of water transfer projects on the trunk basin and contribute to the regulation and management of inter-basin water transfer projects.

Enhancement of EEG-EMG coupling detection using corticomuscular coherence with spatial-temporal optimization.

Objective. Corticomuscular coherence (CMC) is widely used to detect and quantify the coupling between motor cortex and effector muscles. It is promisingly used in human-machine interaction (HMI) supported rehabilitation training to promote the closed-loop motor control for stroke patients. However, suffering from weak coherence features and low accuracy in contingent neurofeedback, its application to HMI rehabilitation robots is currently limited. In this paper, we propose the concept of spatial-temporal CMC (STCMC), which is the coherence by refining CMC with delay compensation and spatial optimization.Approach. The proposed STCMC method measures the coherence between electroencephalogram (EEG) and electromyogram (EMG) in the multivariate spaces. Specifically, we combined delay compensation and spatial optimization to maximize the absolute value of the coherence. Then, we tested the reliability and effectiveness of STCMC on neurophysiological data of force tracking tasks.Main results. Compared with CMC, STCMC not only enhanced the coherence significantly between brain and muscle signals, but also produced higher classification accuracy. Further analysis showed that temporal and spatial parameters estimated by the STCMC reflected more detailed brain topographical patterns, which emphasized the different roles between the contralateral and ipsilateral hemisphere.Significance. This study integrates delay compensation and spatial optimization to give a new perspective for corticomuscular coupling analysis. It is also feasible to design robotic neurorehabilitation paradigms by the proposed method.

Effects of konjac glucomannan/pomegranate peel extract composite coating on the quality and nutritional properties of fresh-cut kiwifruit and green bell pepper.

The effects of an edible coating, based on konjac glucomannan (KG) incorporated with pomegranate peel extracts (PE), on the physicochemical and nutritional properties of fresh-cut kiwifruit and green bell pepper during storage were investigated. The optimal extract time (40.6 min), temperature (54.5 °C), and ultrasound power (255.5 W) with response surface method, provided a high total antioxidant activity (TAA) of (92.31 ± 1.43)%. Fresh-cut kiwifruit and green bell pepper were coated by dipping using five treatments (distilled water, ascorbic acid, KG, PE, KG + PE), packed into polymeric film and stored for 8 days at 10 °C. Distilled water treatment was used as control. KG + PE treatment resulted in the highest total soluble solid and titratable acidity in fresh-cut kiwifruit, while the maximum firmness in fresh-cut green bell pepper. The weight loss was both effectively decreased in samples treated with KG or KG + PE. All samples treated with KG + PE had significantly higher contents of chlorophyll, ascorbic acid, total phenolic and TAA than others. Moreover, the KG + PE group had the lowest counts of microorganisms in all samples. KG coating incorporated with PE was proved to be efficient in maintaining the physico-chemical and nutritional properties of fresh-cut kiwifruit and green bell pepper during low temperature storage compared with control. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13197-021-05006-7.