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Qian-Yun Han Fang Liu Yuan-Ying Ni 《International Journal of Food Science & Technology》2022,57(2):920-930
The gene sequence coding for the membrane-bound polyphenol oxidase (mPPO) with a length of 1761 bp was cloned by PCR method and shown to contain one highly conserved sequence encoding a di-copper-binding region. The predicted three-dimensional structure of mPPO indicated that the active site was located near two copper ions and composed of a typical bundle of four α-helices. Each of the two catalytic copper ions was coordinated with three histidine residues in the hydrophobic pocket, yielding His 180, His 201, His 210, His 332, His 336 and His 366. Docking studies showed that 4-methylcatechol and chlorogenic acid have different binding models due to different ligand sizes and binding sites in the active centre, and it was found that the smaller compound exhibited a higher affinity for mPPO. Molecular dynamic simulation results indicated that Phe 353 is important in controlling enzymatic activity through influencing substrate coordination in the active site. 相似文献
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Qing Li Jun Wang Jie Ma Meng Ni Fan Yang Peng Liu Kuo Yang Lee Hsing-I Hsiang Deyuan Shen Dingyuan Tang 《Journal of the American Ceramic Society》2022,105(5):3375-3381
High-efficiency Yb:Y2O3 laser ceramics were fabricated using the vacuum-sintering plus hot isostatic pressing (HIP) without sintering additives. High-purity well-dispersed nanocrystalline Yb:Y2O3 powder was synthesized using a modified co-precipitation method in-house. The green bodies were first vacuum sintered at a temperature as low as 1430°C and then HIPed at 1450°C. Finally, the samples were air annealed at 800°C for 10 h. Although no sintering aids were used, full density of the samples with excellent optical homogeneity and an inline transmission of 80% at 400 nm could be obtained. Moreover, photodarkening phenomenon was not detected in the ceramics. Preliminary laser experiment with the fabricated ceramics in a two-mirror cavity has demonstrated 32 W continuous-wave (CW) output at ∼1077 nm with an optical-to-optical conversion efficiency of 58.2%. To the best of our knowledge, this is so far the highest CW output power and optical-to-optical conversion efficiency achieved with the Yb3+-doped sesquioxide ceramics in a simple two-mirror cavity. 相似文献
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Xuepeng Ni Zhe Cui Ning Jiang Huifang Chen Qilin Wu Anqi Ju Meifang Zhu 《材料科学技术学报》2021,77(18):169-177
The electrode materials with high pseudocapacitance can enhance the rate capability and cycling stabil-ity of lithium-ion storage devices.Herein,we fabricated MoS2 nanoflowers with ultra-large interlayer spacing on N-doped hollow multi-nanochannel carbon nanofibers(F2-MoS2/NHMCFs)as freestanding binder-free anodes for lithium-ion batteries(LIBs).The ultra-large interlayer spacing(0.78~1.11 nm)of MoS2 nanoflowers can not only reduce the internal resistance,but also increase accessible active sur-face area,which ensures the fast Li+intercalation and deintercalation.The NHMCFs with hollow and multi-nanochannel structure can accommodate the large internal strain and volume change during lithi-ation/delithiation process,it is beneficial to improving the cycling stability of LIBs.Benefiting from the above combined structure merits,the F2-MoS2/NHMCFs electrodes deliver a high rate capability 832 mA h g-1 at 10 A g-1 and ultralong cycling stability with 99.29 and 91.60%capacity retention at 10 A g-1 after 1000 and 2000 cycles,respectively.It is one of the largest capacities and best cycling stability at 10 A g-1 ever reported to date,indicating the freestanding F2-MoS2/NHMCFs electrodes have potential applications in high power density LIBs. 相似文献
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Abidi Syed Muhammad Raza Xu Yonglin Ni Jianyue Wang Xiangmeng Zhang Wu 《Multimedia Tools and Applications》2020,79(47-48):35583-35617
Multimedia Tools and Applications - Film industries all over the world are producing several hundred movies rapidly and grabbing the attraction of people of all ages. Every movie producer is of... 相似文献
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Lei Yuan Mads Frederik Hansen Henriette Lyng Røder Ni Wang 《Critical reviews in food science and nutrition》2020,60(13):2277-2293
AbstractAttachment of microorganisms to food contact surfaces and the subsequent formation of biofilms may cause equipment damage, food spoilage and even diseases. Mixed-species biofilms are ubiquitous in the food industry and they generally exhibit higher resistance to disinfectants and antimicrobials compared to single-species biofilms. The physiology and metabolic activity of microorganisms in mixed-species biofilms are however rather complicated to study, and despite targeted research efforts, the potential role of mixed-species biofilms in food industry is still rather unexplored. In this review, we summarize recent studies in the context of bacterial social interactions in mixed-species biofilms, resistance to disinfectants, detection methods, and potential novel strategies to control the formation of mixed-species biofilms for enhanced food safety and food quality. 相似文献
8.
Replenishment policy for a purchase-to-order seller: a tradeoff between ordering cost and delay cost
Guanqun Ni 《国际生产研究杂志》2020,58(4):1239-1254
We consider replenishment decisions on when and how many goods to purchase for a seller under a purchase-to-order mode where there is no inventory and the seller purchases goods to fulfil orders already placed. For each purchase, there is a constant ordering cost. For each order, delay cost will be incurred if it is not fulfilled timely. Generally, the more frequent the replenishment, the higher the ordering cost but the lower the delay cost. Consequently, there is a tradeoff between the ordering cost and the delay cost for the seller to make replenishment decisions minimising the total cost. In this paper, we study three cases of the problem and investigate both offline versions and online versions according to the seller's knowledge about information of future orders. For offline versions with perfect information, we either develop an optimal policy, or prove it is NP-hard and develop an approximation policy. For online versions without any information about future orders, from the perspective of competitive analysis we prove the lower bound of competitive ratio for any possible online policy and present a 10-competitive online policy for the general case and a 2-competitive online policy for each of two special cases. 相似文献
9.
食品安全网络舆情监测系统在国内外被应用于食品安全风险预警与舆情补救,开发决策参考、监督抽检、专项整治、协查处置等舆情信息应用场景化服务,实现高并发情形下对热点食品安全舆情事件的自动跟踪和分析。为探明该系统进一步的发展方向,本文研究比较了欧美食品安全舆情监测系统的应用状况,分析了不同社会主体应用食品安全舆情监测系统的领域,结合我国实际发展制定相应措施,得出食品安全舆情监测系统与社会共治主体密切联系的结论。从而提出政府、食品企业和消费者三个社会主体在食品安全网络舆情监测系统的推广和应用上的指导方案。同时,食品安全舆情监测有待于借助大数据技术进一步发展,从而开拓出更加丰富的使用功能,以保障人民的食品安全。 相似文献
10.
以铁矿排土场废石土为研究对象,自制模型试验装置,设计4种基质改良方法,开展SEM检测实验,并应用IPP软件对SEM照片进行定量化分析,研究在不同改良措施下对铁矿排土场土壤微结构的影响。结果表明:单施3%有机肥土壤孔隙度为16%,与对照组排土场原矿土相比增加了60%。复合施用3%有机肥、掺拌30%的黄土的处理孔隙度达到最大33%。单施3%有机肥、5%有机肥对土壤大团聚体含量皆有显著的促进作用,复合施有机肥、掺拌黄土的处理与单施有机肥的处理对比,土壤大团聚体含量增加并不显著。各改良措施的MWD与FMD均随着土壤中大团聚体的含量增加而增加。 相似文献