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This article focuses on analyzing and evaluating the demagnetization behavior of Halbach rotor permanent magnet synchronous machines. An indicator related to the dq-axis current namely Idmag representing the severity of the demagnetization is proposed based on the analysis of a finite-element (FE) model. The influence of transient symmetrical short-circuit (SSC) current is considered during the evaluation of the magnets’ magnetization status. Analysis based on the derived analytical solution proved that ignoring the magnetic saturation caused by the transient SSC current will cause significant inaccuracy in the calculation of Idmag. To improve the calculation efficiency and accuracy, a hybrid model combining the equivalent circuit model, several FE cases, and an analytical mapping model is proposed. The procedures for building the hybrid model are elaborated and its accuracy is verified by time-stepping FE analysis. The proposed model can complete the calculation of one case within 20 s whereas conventional FE analysis typically takes over 10 min. Finally, the accuracy of the FE model is verified by experiments on a manufactured prototype. With this proposed model, both the worst demagnetization scenario over the entire operating range and the maximum acceptable PM temperature at a given speed can be identified. The derived temperature boundary will be used to guide the cooling design of the machine.

Permanent magnet synchronous generator (PMSG) is gradually becoming popular in the aeroelectric propulsion system due to its high efficiency and high power density. The selection of stator lamination materials usually requires multiple considerations, including high magnetic performance, low losses, lightweight, and so on. In order to achieve higher efficiency and power density, the electromagnetic structure of the PMSG is optimized, and the electromagnetic performance and weight of various stator lamination materials and thicknesses are also taken into consideration in this article. The magnetic material properties, including ${B}$ – ${H}$ characteristics and losses at different frequencies, are obtained by the test and used to accurately predict the performance of machines. Finally, a 10 kW and 20-pole and 45-slot prototype with 0.1 mm thick 1J22 material is manufactured for the electric propulsion system of Unmanned Aerial Vehicle (UAV). The simulation and experiment results show that the efficiency of the generator system can reach 92.5%, and the power density of the generator is about 2 kW/kg.

ABSTRACT Developing chemically defined (CD) media suited for multiple Chinese hamster ovary (CHO) cell lines can be a challenging and extensive process because of the complexity of cellular metabolism and [...]

Although the synthesis of thiophenol-pendant polymers was reported in the 1950s, the polymers generally suffered from oxidation and became insoluble in organic solvents, hampering detailed characterization and further applications. Dithiocatechol-pendant polymers, which have one additional ortho-thiol group than thiophenol-pendant polymers, have never been synthesized, despite their promise in various applications due to their analogous molecular structure with catechol-pendant polymers. Herein, we report the first synthesis of dithiocatechol-pendant polymers using a novel protection–deprotection strategy. We carefully examined the synthetic routes and identified the deprotection conditions that do not cause cross-linking of the dithiocatechol moieties. Because the resulting dithiocatechol-pendant polymers were soluble in common organic solvents (e.g., tetrahydrofuran and N,N-dimethylformamide), the polymers can be fully characterized by standard spectroscopic methods, providing valuable data for future researchers. We also showed that besides free-radical polymerization, reversible addition–fragmentation chain-transfer polymerization can also be adopted to synthesize dithiocatechol-pendant polymers. This work paves the way for the exploitation of dithiocatechol-containing polymers for the fabrication of novel functional materials.

Drought stress is detrimental to male reproduction in maize (Zea mays L.), largely through reducing the quantity and quality of pollen grains. However, transcriptional response of maize pollen grains to drought stress has not been well documented. We compared pollen gene expression for a maize hybrid (ZhongDan909) under well-watered and drought-stress conditions, based on RNA-Seq validated by quantitative real-time PCR analysis. Expression of 6424 genes and 1302 transcripts was altered in pollen grains of maize subjected to 7days of drought during flowering. Gene Ontology annotations showed 308 differentially expressed genes, annotated and classified into 50 primary functional categories. Kyoto Encyclopedia of Genes and Genomes analyses revealed 44 differentially expressed genes in nine metabolic pathways. In relation to carbohydrate metabolism pathways, there was downregulation of a polygalacturonase gene, which could reduce cell wall lysis in early pollen germination, and an increase in callose synthase transcripts along with reduced cellulase transcripts. These altered gene expressions responsible for cell wall integrity may inhibit the initiation of pollen tube growth. The onset of tube growth could be further impeded by observed changes in gene expression that potentially influence hormone metabolism (including downregulation of AUXIN RESPONSE FACTOR 18 and EIN3-BINDING F-BOX ), reduce mitochondrial function, and alter protein translation. Genes with potential roles in adaptation were also altered in their transcript levels. These included genes encoding the upregulated transcription factor ZmNF-YC2, and the downregulated ZmbHLH13, a negative regulator of jasmonic acid responses. The upregulated flavin enzyme gene DIHYDROLIPOYL DEHYDROGENASE 1 , associated with increased levels of reactive oxygen species, is of interest in relating redox homeostasis to stress adaptation. Overall, the analyses identified a suite of genes involved in the development of pollen grains and tubes and responsive to drought stress. The findings enhance understanding of the gene networks underlying compromised pollen viability under drought stress.

ABSTRACTThe paper explores the influence of IPO over-funding on the cost stickiness. We first document that the liquidity from IPO over-funding has positive association with the cost stickiness in China which indicates that the liquidity supplement from IPO over-funding increases manager’s empire building incentives and reduces company’s operating efficiency. Besides, we find that this positive association is more significant in companies with weak governance in terms of less power balance, lower debt constraints and less institutional investor’s supervision. It is because company’s governance mechanism plays an important role on the efficiency of IPO proceeds. These conclusions provide enlightenment for the current regulation of listed companies.

Quinoa (Chenopodium quinoaWilld.) is a promising nutritious cereal known for its rich nutrition and diverse physiological activities. In order to further investigate the profiles and physiological activities of phenolic compounds from quinoa, the composition of free and bound phenolic extracts from white, red, and black quinoa were analyzed, as well as their antioxidant, anti‐inflammatory, and antitumor activities. Total phenolic content (TPC) and total flavonoid content (TFC) ranged from 514.03 to 1,409.54 mg gallic acid equivalent (GAE)/100g and 177.49 to 407.75 mg rutin equivalent (RE)/100 g, respectively. TPC existed mainly in bound form in red and black quinoa, but free form in white quinoa. Eight individual phenolic acids were detected, with the total acids amount ranging from 86.21 to 188.76 µg/g. Protocatechuic acid was the dominant phenolic acid both in red and black quinoa. Red quinoa showed the highest TPC and TFC, while black quinoa had the highest phenolic acids concentration. Red quinoa also showed the best ABTS and DPPH radical scavenging activities. Positive correlations were found among antioxidant activity and phenolic components. Besides, phenolics from red and black quinoa showed better anti‐inflammatory and antitumor activity by down‐regulating the NO production and inhibiting the proliferation of MCF‐7 cells. Quinoa seed is rich in phenolic components, especially the red and black one. Higher phenolic contents in red and black quinoa can be responsible for their superior antioxidant, anti‐inflammatory, and antitumor activities. With potential health benefits, quinoa phenolics may be used as ingredients for functional food. Findings of this study revealed useful information on phenolics and bioactivity of quinoa for its cultivation and breeding with functional oriented purpose. The results could be also applied in health food industry for quinoa material selection and processing.

Evaporation duct is a special atmospheric stratification that always exists at sea, which has an important influence on electromagnetic wave propagation. Accurate prediction of evaporation duct height is of great significance for radio information system. In the era of big data, machine learning has been widely used in various research work and achieved a series of excellent results. Based on the observation data method, this paper studies the prediction model using Gradient Boosting Regression algorithm (GBR) and proposes the pure data‐driven GBR (PDD_GBR), GBR_Paulus‐Jeske (GBR_PJ), and GBR_Babin‐Young‐Carton (GBR_BYC) evaporation duct prediction models. Simultaneously, traditional Paulus‐Jeske (PJ) model, Babin‐Young‐Carton (BYC) model, and existing SVR_PJ model are introduced into the experiment to make a comparison. The comprehensive performance of PDD_GBR model is optimal among these models with high stability and strong generalization ability, whose prediction accuracy has a great promotion compared with other models. We propose the pure data‐driven GBR (PDD_GBR) model of new evaporation duct prediction modelPDD_GBR model is optimal among these models in experimental area, whose prediction accuracy has a greater promotion than other modelsCompared with PJ and SVR_PJ model, RMSE is reduced by 84.6% and 54.1%, respectively, and SCC is increased by 102.3% and 40.3%, respectively

Late spring cold (LSC) occurred in the reproductive period of wheat impairs spike and floret differentiation during the reproductive period, when young spikelets are very cold-sensitive. However, under LSC, the responses of wheat spikelets at various positions, leaves, and stems and the interactions between them at physiological levels remain unclear. In the present study, two-year treatments at terminal spikelet stage under two temperatures (2 °C, −2 °C) and durations (1, 2, and 3 days) were imposed in an artificial climate chamber to compare the effects of LSC on grain number and yield in the wheat cultivars Yannong 19 (YN19, cold-tolerant) and Xinmai 26 (XM26, cold-sensitive). The night temperature regimes were designed to reproduce natural temperature variation. LSC delayed plant growth and inhibited spike and floret differentiation, leading to high yield losses in both cultivars. LSC reduced dry matter accumulation (DMA, g) in spikes, stems, and leaves, reducing the DMA ratios of the spike to leaf and spike to stem. Plant cell wall invertase (CWINV) activity increased in upper and basal spikelets in YN19, whereas CWINV increased in middle spikelets in XM26. Under LSC, soluble sugar and glucose were transported and distributed mainly in upper and basal spikelets for glume and rachis development, so that spike development was relatively complete in YN19, whereas the upper and basal spikelets were severely damaged and most of the glumes in middle spikelets were relatively completely developed in XM26, resulting in pollen abortion mainly in upper and basal spikelets. The development of glumes and rachides was influenced and grain number per spike was decreased after LSC, with kernels present mainly in middle spikelets. Overall, reduced total DMA and dry matter partitioning to spikes under LSC results in poor spikelet development, leading to high losses of grain yield.

It is highly desirable to prevent crack formation in polymeric materials at an early stage and to extend their lifespan, particularly when repairs to these materials would be difficult for humans. Here, we designed and synthesized catechol-functionalized polymers that can self-heal in seawater through hydrogen bonding and coordination. These bioinspired acrylate polymers are originally viscous materials, but after coordination with environmentally safe, common metal cations in seawater, namely, Ca2+and Mg2+, the mechanical properties of the polymers were greatly enhanced from viscous to tough, hard materials. Reduced swelling in seawater compared with deionized water owing to the higher osmotic pressure resulted in greater toughness (∼5 MPa) and self-healing efficiencies (∼80%).

To establish and optimize the propagation of Nianmaohuangqin (Radix Scutellariae Viscidulae)and induce and characterize polyploidy of Nianmaohuangqin (Radix Scutellariae Viscidulae).

In this study, we examine the use of green fluorescent protein (GFP) for monitoring a hexokinase (HXK)–GFP fusion protein in Saccharomyces cerevisiae for various events including expression, degradation, purification, and localization. The fusion, HXK-EK-GFP-6 × His, was constructed where the histidine tag (6 × His) would allow for convenient affinity purification, and the enterokinase (EK) cleavage site would be used for separation of HXK from GFP after affinity purification. Our results showed that both HXK and GFP remained active in the fusion and, more importantly, that there was a linear correlation between HXK activity and GFP fluorescence. Enterokinase cleavage studies revealed that both GFP fluorescence intensity and HXK activity remained unchanged after separation of the fusion proteins, which indicated that fusion of GFP did not cause structural alteration of HXK and thus did not affect the enzymatic activity of HXK. We also found that degradation of the fusion protein occurred, and that degradation was limited to HXK with GFP remaining intact in the fusion. Confocal microscopy studies showed that while GFP was distributed evenly in the yeast cytosol, HXK-GFP fusion followed the correct localization of HXK, which resulted in a di-localization of both cytosol and the nucleus. GFP proved to be a useful fusion partner that may lead to the possibility of integrating the bioprocesses by quantitatively following the entire process visually. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 79: 682–693, 2002.

While it has been demonstrated that GFP‐tagged proteins were transported to their correct cellular compartments in most cells, attempts to secrete GFP/GFP‐fusion through the default secretory pathway have not been as successful. In an attempt to induce secretion of GFP and Hexokinase (HXK)‐GFP fusion in Saccharomycescerevisiae, we have cloned constructs that employed four different yeast secretion signal sequences, i.e., INU1, SUC2, PHO5, and MEL1. The expression is under the control of the galactose‐inducible GAL1promoter. Our results showed that all eight constructs entered the secretory pathway successfully, and the signal peptides were all cleaved off. However, none of the eight constructs were able to lead to secretion into the culture media or the periplasmic space. The expression levels of the eight constructs differ dramatically, depending on both the signal peptide and whether GFP was fused with HXK. Confocal microscopy studies revealed that the eight constructs also led to very different localization patterns. Among them, two constructs targeted GFP to the vacuole partially or exclusively, whereas others were mostly retained in the ER/Golgi compartments. Our efforts, together with those of others, seem to suggest that the signal peptide itself is not enough to lead to secretion of GFP from S. cerevisiae, although it has been successful in some other organisms. Nonetheless, the advantage of GFP's in vivo detection makes it a powerful tool for investigating protein localization events.

Green fluorescent protein (GFP) was used to study the regulation of the galactose-inducible GAL1 promoter in yeast Saccharomyces cerevisiae strains. GFP was cloned into the pGAL110 vector and transformed into the yeast strains. Time course studies comparing culture fluorescence intensity and GFP concentration were conducted along with on-line monitoring of GFP expression. Our results demonstrated that GFP fluorescence could be used as a quantifiable on-line reporter gene in yeast strains. The effect of an integrated GAL10p-GAL4 transcription cassette was investigated. Induction time studies showed that there was no significant difference in GFP expression level by adding galactose at different culture times. A wide range of galactose concentrations was used to study the initial galactose concentration effect on GFP expression kinetics. A minimum of 0.05 g/L galactose doubled the GFP fluorescence signal as compared to the control, whereas 0.1 g/L gave the highest specific GFP yield. A simple analytical model was proposed to describe GFP expression kinetics based on the experimental results. In addition, this GFP-based approach was shown to have potential use for high-throughput studies. The use of GFP as a generic tool provided important insights to the GAL expression system and has great potential for further process optimization applications. © 2000 John Wiley & Sons, Inc. Biotechnol Bioeng 70: 187–196, 2000.

Synthesis of an operon fusion protein was investigated in batch and fed-batch cultures at high cell densities of recombinant Escherichia coli JM105 [pBAD-GFP::CAT]. Glucose-limited growth was achieved without accumulation of inhibitory byproducts allowing high cell densities (110 g L⁻¹ DCW) to be attained. This was believed to be the highest reported value for dry cell mass of E. coli strain JM105 expressing two recombinant proteins. Transcription of the two reporter genes, green fluorescent protein (GFP) and chloramphenicol acetyltransferase (CAT), was under the control of the pBAD promoter of the araBAD (arabinose) operon. Each protein was independently translated via separate ribosome binding sites. CAT served as a model recombinant protein product to illustrate the noninvasive quantitative reporting ability of GFP during high cell density fermentations. Expression of GFP was monitored on-line using an intensity-based optical sensor. A linear correlation between the on-line GFP intensity and the enzymatic activity of CAT allowed for in vivo real-time quantitative monitoring of a fermentation product under conditions of high biomass concentration and high productivity. © 1999 John Wiley & Sons, Inc. Biotechnol Bioeng 65: 54–64, 1999.