Search

Excessive nitrogen (N) use in agriculture, industry, and household waste leads to widespread N release throughout the environment, causing eutrophication in both freshwater and coastal areas. To better understand N-induced eutrophication and other N-use-related environmental impacts at the local scale, improvements in the spatial resolution of life cycle impact assessment measures are required. Here, we present a method to estimate gridded fate factors (FFs) at a half-degree resolution based on the Integrated Model to Assess the Global Environment-Global Nutrient Model to provide eutrophication indicators for global N-related manufacture, trade, and consumption in life cycle assessment. Across global freshwater systems, our cumulative FFs have a 5th percentile of 0.9 days and a 95th percentile of 184.0 days. Aggregated FFs for administrative units range from 0.3 days to 211.9 days. The hotspots of cumulative FFs are mainly distributed upstream of large reservoirs or lakes. On a global level, advection is the dominant process controlling the FF (69.7% of areas), followed by retention (29.0%), and water consumption (1.3%). N retention dominates in advection-favoring, high-discharge regions due to the high residence times, while water consumption tends to dominate water-scarce zones. The results demonstrate the importance of gridded information to assess eutrophication impacts, as it characterizes N emissions from anthropogenic sources at high spatial resolution in comparison to basin- or country-level assessments. Introducing soil–freshwater N fate complements existing P-related fates to improve global assessments of eutrophication. This article met the requirements for a Gold–Gold Badge JIE data openness badge described at http://jie.click/badges.

Neonicotinoids are the most widely used insecticides worldwide, but there is mounting evidence demonstrating that they have adverse effects on nontarget organisms. However, little is known about the extent of environmental neonicotinoids contamination in China. In this study, a total of 693 honey samples from across China, from both Apis melifera and Apis cerana, were analyzed to examine neonicotinoid concentrations and their geographical distribution, and correlation with the primary plant species from which the honey was obtained. Furthermore, chronic and acute exposure risk and risk ranking for humans eating honey were investigated, and risks to bees were also considered. The results revealed that 40.8% of the samples contained at least one of the five neonicotinoids tested. Honeys from commercial crops were found to be more frequently contaminated with neonicotinoids than those from noncommercial crops. Honey samples from Apis mellifera were more frequently contaminated than those from Apis cerana. The concentrations of neonicotinoids found in honey overlapped with those that have been found to have significant adverse effects on honeybee health. The dietary risk assessments indicated that the levels of neonicotinoids detected in honey were likely to be safe for human consumption.

Brown macroalgae are an important source of polyphenols with multiple health functions. In this work, polyphenol extracts from Lessonia trabeculate were purified and investigated for the antidiabetic activity in vitro and in vivo. The purified polyphenol extracts exhibited good antioxidant activities, α-glucosidase and lipase inhibition activities (IC50 < 0.25 mg/mL). The HPLC-DAD-ESI-MS/MS analysis indicated that the compounds in polyphenol extracts were mainly phlorotannin derivatives, phenolic acid derivatives, and gallocatechin derivatives. In vivo, C57BL/6J rats treated with polyphenol extracts for 4 weeks had lower fasting blood glucose levels, insulin levels, as well as better serum lipid profiles and antioxidant stress parameters, compared with the diabetic control (DC) group. Histopathology revealed that polyphenol extracts preserved the architecture and function of the liver. Short-chain fatty acid contents in rats' fecal samples with polyphenols administration were significantly recovered as compared with the DC group. Furthermore, the gut microflora of rats was investigated with high-throughput 16S rRNA gene sequencing and results indicated that polyphenol extracts had a positive effect on regulating the dysbiosis of the microbial ecology in diabetic rats. All of the results from the study provided a scientific reference of the potentially beneficial effects of L. trabeculate polyphenols on diabetes management.

Apocynum venetum has a long history as a Chinese traditional tea. As one of the major components, polysaccharides from Apocynum venetum leaves were extracted with acid (HCl), distilled water and alkaline (NaOH) to study the effect of the extraction solvents on their chemical composition and biological activities in this work. Monosaccharide composition revealed that polysaccharides from acidic and distilled water extraction were pectic polysaccharides, while those from alkaline extraction consisted of pectin and hemicellulose. Chemical analysis and FT-IR spectra indicated the co-extraction of protein and polyphenol contents in alkaline extracted polysaccharides, which exhibited strongest antioxidant and digestive enzyme inhibition activities. The antioxidant capacities were 185.26–286.30 mg TE/g for DPPH radical scavenging, 409.06–502.00 mg TE/g for ABTS radical scavenging, and 152.12–260.70 mg TE/g sample for reducing power assay, respectively. The lowest IC50 for α-glucosidase and lipase inhibition activities were 16.75 μg/mL and 820 μg/mL, respectively. Further purification of alkaline extracts was carried out and characterized. The results showed that acid hydrolysis could successfully reduce polyphenol and protein contents, and purified polysaccharides showed even higher antioxidant activities and α-glucosidase inhibition activity. These results provide a scientific support for functional application and extraction of polysaccharides from Apocynum venetum leaves.

Sword-leaf dogbane (Apocynum venetum) is a traditional Chinese herb with increasingly recognized potential to enhance health, but no study of stable reference genes in this herb has been reported. Based on a homologous cloning strategy, we have successfully cloned five candidate reference genes from sword-leaf dogbane: glyceraldehyde-3-phosphate dehydrogenase (AvGAPDH), beta tubulin (AvbTUB), polyubiquitin (AvUBQ), elongation factor 1-alpha (AvEF1α), and actin (AvACTIN). Three distinct algorithms, geNorm, NormFinder, and BestKeeper, were used to estimate the expression stability of candidate reference primer pairs. We found that AvACTIN-2 and AvACTIN-3 presented the highest stability of expression in different tissue samples, and AvGAPDH-2 was most stable under salinity stress. In addition, we illustrated the application of these new reference genes by assaying the expression levels of two hyperoside biosynthesis terminal enzyme genes, flavonoid 3′-hydroxylase (F3′H) and flavonol synthase (FLS), under salinity stress. Our study is the first to report stable expression of internal reference genes in sword-leaf dogbane in multiple experimental sample sets.

Apocynum venetum L. is a traditional Chinese medicinal herb with great potential to treat angiocardiopathy. Its major medicinal constituents are flavonoids. However, the natural habitats of A. venetum are typically affected by salt stress, which can modify both biomass and accumulation of medicinal compounds. In this study, the effects of salt stress on growth and development of A. venetum, accumulation of flavonoids and expression patterns of genes involved in flavonoid biosynthesis were evaluated. In general, the growth and development of seedlings (seedling height, root length, leaf length, leaf width and seed germination) were inhibited by salt stress. Unlike typical halophytes, there was no optimal NaCl concentration range that promoted growth and development, but seedlings had an elevated DW/FW ratio under salt stress (induced by irrigation with 50, 100, 200 or 400 mm NaCl). Furthermore, quercetin and kaempferol were significantly accumulated in A. venetum seedlings under salt stress, resulting in a balanced content and reduced FW. Moreover, the expression of AvCHS, AvCHI and AvF3GT was inhibited by salt stress; however, AvF3'H, AvF3H and AvFLS, which are involved in the flavonol synthesis pathway, were up-regulated under salt stress, consistent with a decrease in total flavonoids and an increase of flavonols (quercetin and kaempferol). In summary, cultivation of A. venetum in saline soils appeared to be feasible and improved the medicinal quality of A. venetum (quercetin and kaempferol accumulation under salt stress), thus this species can effectively utilize saline soil resources.

Microwave-assisted hydrothermal extraction of non-structural carbohydrates and hemicelluloses from tobacco biomass was investigated. Non-structural carbohydrates extraction was optimized by an Optimal design. The maximum yields for the leaf and stem were 118.57 mg/g and 120.33 mg/g biomass, respectively. The extracted stem residue was further treated for hemicelluloses extraction. A temperature of 200 °C without holding was proved to be the most efficient condition to produce a hemicelluloses yield of 105.15 mg/g. GPC results showed that the Mw values of precipitated hemicelluloses decreased from 143.5 kDa to 13.25 kDa with increasing temperature and holding time, while the un-precipitated fraction were ranging from 11.83 to 4.88 kDa. Monosaccharide analysis revealed that hemicelluloses extracted at lower temperature are heterogeneous compositional type, including xylan, glucuronoxylan and xylanglucan, while the ratio of xylose increased significantly (up to 72.64%) with increasing temperature. The developed microwave-assisted hydrothermal extraction process opens new avenues for a sustainable tobacco-based biorefinery.

This paper proposes a dispatch strategy for the multi-energy system (MES) that utilizes the district heating network (DHN) to realize the heat power interaction of multi cogeneration system, so as to improve the operational flexibility. A novel model for the DHN that couples multi heat sources and is under quantity regulation is proposed, based on which an optimal coordinated dispatch model (OCDM) for the MES is presented comprehensively. The DHN model comprises dispatch constraints (DCs) and linear system of temperature correction equations (TCEs). The DCs form part of the OCDM constraints, where the mass flow temperatures are treated as constants and the mass flow rates and heat power are decision variables. The TCEs are employed to update the mass flow temperatures in DCs. Subsequently, an iterative solving strategy for the OCDM is proposed. The convergence of the solving strategy is analyzed and an effective method is introduced to ensure the convergence. A modified system based on an actual MES in Changchun, China is researched in the case study. Three cases are given to verify the effectiveness of the dispatch strategy and the solution method as well as study the influence of wind power penetration and heating level to the results.

With the expanding application of natural ester insulating transformers in distribution area, the economic operation of distribution network becomes more and more important in order to reduce the overall cost in a distribution transformer’s life cycle. The imbalanced three-phase load increases the loss of transformers, and results in low voltage problem in the heavy load phase or even damages to customer’s electrical equipment. In this paper, a multi-objective optimal commutation mathematical model is established and verified to optimize the performance of the three-phase load imbalance regulation based on commutation switches. Compared with the common devices such as reactive compensation and SVG, the real-time online commutation switch system with an automatic commutation control strategy based on proposed vector genetic algorithm displays a better performance in reducing the power loss of distribution area as well as in solving the low voltage problem of users. We expect it to be a competitive solution for the economic and efficient operation of the distribution power grid.

As the global energy crisis, environmental pollution, and global warming grow in intensity, increasing attention is being paid to combined cooling, heating, and power (CCHP) systems that realize high-efficiency cascade utilization of energy. This paper proposes a bilateral transaction mechanism between a residential CCHP system and a load aggregator (LA). The variable energy cost of the CCHP system is analyzed, based on which an energy pricing strategy for the CCHP system is proposed. Under this pricing strategy, the electricity price is constant, while the heat/cool price is ladder-shaped and dependent on the relationship between the electrical, heat, and cool loads. For the LA, an integrated demand response program is proposed that combines electricity-load shifting and a flexible heating/cooling supply, in which a thermodynamic model of buildings is used to determine the appropriate range of heating/cooling supply. Subsequently, a two-stage optimal dispatch model is proposed for the energy system that comprises the CCHP system and the LA. Case studies consisting of three scenarios (winter, summer, and excessive seasons) are delivered to demonstrate the effectiveness of the proposed approach, and the performance of the proposed pricing strategy is also evaluated by annual operation simulations.

L-glutathione (GSH) capped ZnSe quantum dots (QDs) were prepared by microwave-assisted aqueous synthesis. Then, the resulting QDs were illuminated under dark, ultraviolet light and incandescent light, respectively. Thereby effect of lighting on the structures and properties of QDs were studied systematically. It was revealed that particle size and element content of QDs took a sharp change after irradiation, while the crystal structure maintains nearly unaffected. Comparing to the ZnSe QDs under dark condition, counterparts irradiated by UV light possessed outstanding sphericity, size distribution and dispersion. And the content of sulfur (S) in ZnSe QDs irradiated by UV light was much higher relatively. The effect of lighting on vibration peaks of O-H was considerable. However, this effect was observed to be weak on other chemical bonds. The possible explanation ascribes to photo-chemical interactions can occur between S-H and O-H bonds on the surface of GSH ligand. The lighting induced GSH to occur photocatalytic oxidation on the surface of ZnSe QDs, which improved the optical properties of QDs. The effects of lighting rely on irradiation types, the sequence is UV light, incandescent light and dark from high to low.

Live line operation is the most direct and effective means for the maintenance of multi-circuit transmission lines on the same tower. It is also a special operation mode developed to improve the reliability of power supply and the safety of power grid. Therefore, it is necessary to analyze the feasibility of live line operation of multi-circuit transmission lines on the same tower. In this paper, 110 kV, 220 kV and 500 kV multi-circuit transmission lines on the same tower are taken as object, and the safety analysis of live working is carried out for typical working positions. According to the results of operation impact discharge test, the risk rate and safe working distance of live working are obtained; Finally, the minimum effective insulation length of load-bearing tools and operation tools is calculated.

500kV double circuits on the same tower can effectively improve the natural transmission power and reduce the width of the line corridor, but the electromagnetic environment under the conductor is deteriorated. In order to ensure the safety of the workers in the insulated aerial vehicles and equipment during the live working, this paper firstly calculates the electric field distribution on the operating surface of the 500kV double-circuits truck with the actual line parameters, and then defines the distance coefficient. The existing minimum safe distance formula is modified, and a reference calculation method of the distance coefficient is given in combination with the data in the paper. Finally, the simulation data is used to verify.

The phenolic and proline content were determined in honey samples of different floral origins (rapeseed, sunflower, buckwheat and Codonopsis) from five different regions of China. The phenolic and proline profile of these samples were used to construct a statistical model to distinguish honeys from different floral origins. Significant differences were identified among the studied honey samples from multivariate chemometric methods. The proline content varied among the four types of honeys, with the values decreasing in the order: buckwheat > Codonopsis > sunflower > rapeseed. Rapeseed honeys contained a high level of benzoic acid, while rutin, p-coumaric acid, p-hydroxybenzoic acid were present at relatively high levels in buckwheat honeys. Principal component analysis (PCA) revealed that rapeseed honey could be distinguished from the other three unifloral honeys, and benzoic acid, proline and kaempferol could serve as potential floral markers. Using 18 phenolic compounds and proline the honey samples were satisfactorily classified according to floral origin at 94% correct prediction by linear discriminant analysis (LDA). The results indicated that phenolic compounds and proline were useful for the identification of the floral origin of the four type honeys.

Invisible cloaks, which used to appear as a magic item by super hero for some special goals, have been turned into reality in scientific research by the transformation optics method, especially linear transformation and conformal transformation. All the invisibility cloaks focus on nano- or micro-fabricated artificial composite materials, and for the different spatial electromagnetic properties. In this paper, the electromagnetic parameters of cloak which is suitable for particular bump and the carpet invisibility cloak based on conformal mapping are calculated. Then, using COMSOL Multiphysics simulation, I simulate the performance of the designed carpet invisibility cloak using the simplified parameters. The cloak with a particular shaped bump operates at infrared frequencies and fulfills the requirement of hiding the objects, for a special light polarization. Moreover, this paper also reported a most unusual plasmonic grating invisibility cloak based on conformal mapping, which focus more on microwave frequencies, designed to reshape negatively refracting lenses and cloaks of invisibility. The cloak overcomes the drawback of quasi-conformal mapping, where unwanted lateral shifts happens, providing the new method for design the invisibility cloak. Hence, the work broadens the ways for future applications with macroscopic cloaking devices. Keywords: Carpet invisibility cloak; Transformation optics; Metamaterial; Conformal mapping; Linear transformation Master of Science (Electronics)

A rapid ultra-performance liquid chromatography (UPLC) method was developed for feasible separation and quantification of 26 amino acids in royal jelly. The analysis was performed on Acquity UPLC system with Acquity UPLC AccQ·Tag Ultra Column within 8 min. The correlation coefficient values ( r 2 > 0.9978) indicated good correlations between the investigated compounds’ concentrations and their peak areas within the test ranges. The limits of quantitation and detection of 26 amino acids were 42.7–235.1 ng/mL and 12.9–69.3 ng/mL, respectively. The recoveries ranged from 90.1% to 100.9% and the overall relative standard deviations for intra- and inter-day were lower than 2.8%. The results showed that UPLC was a powerful tool for the analysis of amino acids in royal jelly. The method was also applied to quantitatively determine free amino acid (FAA) and total amino acid (TAA) profiles in RJ samples stored at different temperatures (−18 °C, 4 °C and 25 °C) for different time intervals (1, 3, 6 and 10 months). Results showed that the average contents of FAA and TAA in fresh royal jelly were 9.21 mg/g and 111.27 mg/g, respectively; the major FAAs were Pro, Gln, Lys, Glu, and the most abundant TAAs were Asp, Glu, Lys and Leu. Although the concentration of most FAAs and TAAs showed no significant difference during storage, contents of total Met and free Gln decreased significantly and continuously, and might be a parameter to predict the quality of royal jelly.