In recent years, the physical fitness of college students has been declining year by year, which has become the focus of national concern. In this paper, firstly, the human body motion tracking based ...on a multi-objective optimization algorithm is applied in the auxiliary training of college students’ sports to provide data support for the formulation of sports plans, and the Chebyshev function evolution calculation is used to obtain the Pareto optimal solution for sports training. Secondly, the similarity function between the two-dimensional projection of the skeleton and the silhouette of the image is established in the constructed human body model so as to calculate the multi-objective optimization function. The optimized training plan was specifically analyzed after analyzing the sports assessment of college students in X school. The results show that compared with the conventional training plan, the optimized training plan has more sports load intensity indexes distributed between 1.5 and 2.0, indicating that the plan is more scientific and effective. The research presented in this paper can be a valuable resource for the creation of sports programs for college students.
The analysis of the existing constraints of “sports season teaching mode” is of great significance to the reform of physical education in colleges and universities. In this paper, the model structure ...and method steps of the hierarchical analysis method are studied, and FHAP with a fuzzy set is proposed for the defects of the consistency test of the judgment matrix. Finally, the weights of each constraint factor are calculated by fuzzy matrix. In the dimension of hardware teaching environment, the importance ratings of “sports venue” relative to other factors are 0.26, 0.74, 0.87, 0.64 and 0.86, and the top three constraints are “sports facilities”, “sports venue,” and “sports facilities”. The top three constraints were “sports facilities”, “sports venues”, and “student-teacher ratio”. Based on FAHP, the key constraints can be analyzed from qualitative and quantitative perspectives, which can provide a scientific and effective reference for developing the teaching mode of the college sports season. The FAHP study analyzed the key constraints from qualitative and quantitative perspectives, which can provide scientific reference for developing the college sports season teaching model.
Flower-like zinc molybdate (ZnMoO4) has been prepared by using a facile hydrothermal method. The ZnMoO4 nanoflowers are characterized by X-ray diffraction, Raman spectroscopy, X-ray photoelectron ...spectroscopy, transmission electron microscopy and scanning electron microscope techniques. The as-prepared material is evaluated as electrode materials for high-performance supercapacitors by cyclic voltammogram, galvanostatic charge-discharge and electrochemical impedance spectroscopy. In 2.0 M KOH electrolyte, the ZnMoO4 nanoflowers display a high specific capacitance of 704.8 F g−1 (three-electrode system). Moreover, the ZnMoO4 nanoflowers can reach up to 568.3 F g−1 at 5.0 A g−1, and approximately 93.6% of the capacitance is retained after 10000 cycles at 8.0 A g−1. A symmetric supercapacitor is fabricated based on ZnMoO4 nanoflowers and activated carbon, and a specific capacitance of 63.13 F g−1 is obtained at 1.0 A g−1 with a high energy density of 22.45 Wh kg−1 at power density of 800.06 kW kg−1. The good electrochemical performance of ZnMoO4 nanoflower not only is due to its unique nanostructures with large specific surface area, but also its excellent conductivity, which facilitates efficient charge transport and promotes electrolyte diffusion. These results indicate that the ZnMoO4 nanoflower may be a promising electrode material for energy storage applications.
•Flower-like zinc molybdate has been prepared by using a facile hydrothermal method.•A symmetric supercapacitor was fabricated based on flower-like zinc molybdate and activated carbon.•ZnMoO4 nanoflowers displayed a specific capacitance of 704.8 F g−1 at 1.0 A g−1 and kept 93.6% 10000 cycles at 8.0 A g−1.•The symmetric supercapacitor showed an energy density of 22.45 Wh/kg at power density of 800.06 kW/kg.
This article addresses the exponential input-to-state stabilization problem for switched reaction–diffusion systems, in which the systems’ mode jumping complies with the persistent dwell-time ...switching mechanism. On the basis of point measurement, a novel pointwise controller is designed to reduce the amount of sensors and actuators. Then, a hysteresis quantizer with an adjustable parameter is employed to balance the quantitative effect and system’s performance, which can improve the bandwidth utilization of the network, simultaneously. Finally, the effectiveness of the proposed approach is demonstrated by an application of the temperature control of power semiconductor chips.
An electrochemical synthesis of functionalized (aza)indolines through dehydrogenative 3+2 annulation of arylamines with tethered alkenes has been developed. Previous reported syntheses through ...similar inter‐ and intramolecular annulation reactions required noble‐metal catalysts and are mostly limited to terminal alkenes or 1,3‐dienes. The electrosynthesis employs the easily available and inexpensive ferrocene as the molecular catalyst and is compatible with di‐, tri‐ and even tetrasubstituted alkenes to construct indolines as well as the more challenging azaindolines. Employing the newly developed electrosynthesis as a key step, the total synthesis of marine alkaloid (±)‐hinckdentine A has been achieved in 12 steps (longest linear sequence) from commercially available materials.
Environmental pollution and food safety are two of the most important issues of our time. Soil and water pollution, in particular, have historically impacted on food safety which represents an ...important threat to human health. Nowhere has that situation been more complex and challenging than in China, where a combination of pollution and an increasing food safety risk have affected a large part of the population. Water scarcity, pesticide over-application, and chemical pollutants are considered to be the most important factors impacting on food safety in China. Inadequate quantity and quality of surface water resources in China have led to the long-term use of waste-water irrigation to fulfill the water requirements for agricultural production. In some regions this has caused serious agricultural land and food pollution, especially for heavy metals. It is important, therefore, that issues threatening food safety such as combined pesticide residues and heavy metal pollution are addressed to reduce risks to human health. The increasing negative effects on food safety from water and soil pollution have put more people at risk of carcinogenic diseases, potentially contributing to ‘cancer villages’ which appear to correlate strongly with the main food producing areas. Currently in China, food safety policies are not integrated with soil and water pollution management policies. Here, a comprehensive map of both soil and water pollution threats to food safety in China is presented and integrated policies addressing soil and water pollution for achieving food safety are suggested to provide a holistic approach.
•Water scarcity, pesticide over-application, and chemical pollutants are key factors impacting food safety.•Increasing negative effects on food safety from water and soil pollution pose health risk.•Cancer clusters caused by mixed pollution co-located with major food production areas.•Integrated policies addressing soil and water pollution for achieving food safety are suggested.
Polyfluoroalkyl substances (PFASs) enter into environmental metric via various pathways in the process of manufacturing and consuming the products containing PFASs. Yuqiao reservoir (YQR) is a major ...drinking water source in Tianjin of China, where little attention was given to PFASs. To explore the occurrence, source and risk of 17 PFASs, multi-media environmental including soil, water, and sediment were sampled from this water source area. The ∑PFASs concentrations of surface water, groundwater, soil and sediment ranged from 5.839 to 120.885 ng/L, 1.426 to 17.138 ng/L, 0.622 to 5.089 μg/kg dw, and 0.240 to 1.210 μg/kg dw respectively. Some short-chained (C4-C8) PFASs were detected widely such as PFOA, PFBA, PFHxA, PFBS, PFHpA and PFPeA in surface water and groundwater, with the detection frequency of ＞78%, and PFBA and PFOA dominated in the 17 PFASs. In addition, the correlations between total PFASs and TOC were significant at 0.05 level, especially in surface water with R2 = 0.9165 (p = 0.011). In terms of vertical distribution characteristics of ∑PFASs, the ∑PFASs in four sediment cores showed a decreasing trend at first, and then an increasing trend from the bottom to the top associated with TOC. PFBA/PFOA and PFHpA/PFOA showed better linear correlations with R2 of 0.5541 (p = 0.039), and for PFNA/PFOA and PFHpA/PFOA with R2 of 0.6312 (p = 0.032) at the 0.05 level in the surface water, which indicated that sewage and atmospheric precipitation were the major sources. Though the RQ results based on the measured concentrations and reference values in environmental media revealed lower risks, the potential hazard may occur due to accumulation characteristics and long-distance transmission capability of PFASs. Hence, the corresponding management strategies should be taken, such as control over emission at source, product substitution and strengthening legislation, to eliminate potential risks to human health.
•PFASs in multi-media environment of drinking water source area were analyzed.•Vertical distributions of PFASs in sediment core profile were presented.•The profile compositions of PFASs were applied to reveal their potential origins.
Background and Aim
Recently, there has been burgeoning interest in the utilization of fully covered self‐expandable metal stents (FCSEMSs) for managing main pancreatic duct strictures (MPDS) in ...chronic pancreatitis (CP). The primary aim was to investigate stricture resolution and recurrence rates of FCSEMS placement in patients with symptomatic CP complicated with MPDS.
Methods
MEDLINE, EMBASE, and ISI Web of Science and Cochrane Library (up to December 2019) were searched to identify eligible studies. A meta‐analysis of stricture resolution and recurrence rates was carried out using R. The crude rate of adverse events related to stent therapy was also calculated.
Results
Ten studies involving 163 patients were included. The weighted pooled rate of MPDS resolution was 93% (95% confidence interval 95%CI 84–99%) with substantial heterogeneity (I2 = 63%). Duration of stent placement more than 3 months did not result in a significantly higher resolution rate than that of 3 months or less (93% vs 93%, P = 0.91). The weighted pooled rate of stricture recurrence was 5% (95%CI: 0–12%). The stricture recurrence rate for patients with duration of stent placement more than 3 months (3%; 95%CI: 0–10%) was lower than that in patients with 3 months or less of stent placement (7%; 95%CI: 0–23%), but not significantly (P = 0.45). The overall rate of adverse events related to stent therapy was 34.9%, and spontaneous stent migration occurred in 14.1% of patients.
Conclusions
The use of FCSEMSs appears to be effective and safe in the management of MPDS caused by symptomatic CP.
Synergetic optical resolution and chiral amplification of tetrahedral Ti4L6 cages by enantiopure coordination cations have been realized in this work. Anionic ΔΔΔΔ-Ti4L6 and ΛΛΛΛ-Ti4L6 cages (L = ...embonate) have been completely resolved by enantiopure Λ-Mn(1R,2R-DCH)3 and Δ-Mn(1S,2S-DCH)3 cations, respectively. Accordingly, two homochiral compounds (PTC-108(Δ) and PTC-108(Λ)) with three-dimensional supramolecular architectures were formed, containing larger diamondoid cages. Such an unusual resolution process clearly shows the stepwise transfer of homochirality from an enantiopure molecule to a resolved hydrogen-bonding aggregation and a final homochiral framework. Moreover, the separated homochiral Ti4L6 cage presents enantioselective recognition toward chiral organic and pharmaceutical molecules. This work opens a novel resolution-dependent homochiral framework construction approach, and it also takes the homochiral tetrahedral Ti4L6 cages with high solubility and stability into promising enantioselective application.
With the shift of fluorine chemical industry from developed countries to China and increasing demand for fluorine chemical products, occurrence of perfluoroalkyl substances (PFASs) in production and ...application areas has attracted more attention. In this study, 153 soil samples were collected from 21 cities along the urbanizing coastal area of the Bohai and Yellow Seas. PFASs in this area were relatively higher, compared with other study areas. The concentrations ranged from 2.76 to 64.0 ng g−1, and those in most sites were between 2.76 and 13.9 ng g−1, with a predominance of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). Among the 21 coastal cities, contaminations of PFASs in Zibo, Nantong and Binzhou were elevated, which was likely affected by local fluorine chemical plants, equipment manufacturing and chemical industry, respectively. The total emissions of PFOA and PFOS were similar, with amount of 4431 kg and 4335 kg, respectively. Atmospheric deposition was the largest source, accounting for 93.2% of total PFOA and 69.6% of PFOS, respectively. In addition, due to application of aqueous film-forming foams (AFFFs) and sulfluramid, disposal of sewage sludge and stacking of solid waste, emission of PFOA and PFOS to soil was 1617 kg, accounting for 9.29% of the whole China. In general, pollution in Jiangsu, Shandong and Tianjin was more serious than those in Liaoning and Hebei, which was consistent with industrialization level and size of industrial sectors emitting PFASs.
Display omitted
•Direct and indirect sources for PFASs in soils along coastal area were quantified.•Relationship from emission of PFASs to actual detection was established.•Concentrations of PFASs in soils along coastal area ranged from 2.76 to 64.0 ng g−1.•Atmospheric deposition of PFOA and PFOS were 4431 and 4335 kg, respectively.•Direct emission of PFOA and PFOS was 1617 kg, contributing 9.3% in whole China.
Atmospheric deposition contributed 8766 kg PFOA and PFOS for coastal areas along the Bohai and Yellow Seas, which accounted for 70.8% of the total sources.
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