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Massive MIMO TWO-Hop Relay Systems Over Rician Fading Channels
( Jian Cao ),( Shujuan Yu ),( Jie Yang ),( Yun Zhang ),( Shengmei Zhao ) 한국인터넷정보학회 2019 KSII Transactions on Internet and Information Syst Vol.13 No.11
With the advent of the fifth-generation (5G) era, Massive multiple-input multiple-output (MIMO) relay systems have experienced the rapid development. Recently, the performance analysis models of Massive MIMO relay systems have been proposed, which are mostly based on Rayleigh fading channels. In order to create a more suitable model for 5G Internet of Things scenarios, our study is based on the Rician fading channels, where line-of-sight (LOS) path exists in the channels. In this paper, we assume the channel state information (CSI) is perfect. In this case, we use statistical information to derive the analytical exact closed-form expression for the achievable sum rate of the uplink for the Massive MIMO two-hop relay system over Rician fading channels. Moreover, considering the different communication scenarios, we derive the analytical exact closed-form expression for the achievable sum rates of the uplink for other three scenarios. Finally, based on these expressions, we make simulations and analyze the performance under different transmit powers and Rician-factors, which provides a theoretical basis and reference for further research.
Yu, Lu,Chen, Yuan,Shi, Jie,Wang, Rufeng,Yang, Yingbo,Yang, Li,Zhao, Shujuan,Wang, Zhengtao The Korean Society of Ginseng 2019 Journal of Ginseng Research Vol.43 No.1
Background: Ginsenosides are known as the principal pharmacological active constituents in Panax medicinal plants such as Asian ginseng, American ginseng, and Notoginseng. Some ginsenosides, especially the 20(R) isomers, are found in trace amounts in natural sources and are difficult to chemically synthesize. The present study provides an approach to produce such trace ginsenosides applying biotransformation through Escherichia coli modified with relevant genes. Methods: Seven uridine diphosphate glycosyltransferase (UGT) genes originating from Panax notoginseng, Medicago sativa, and Bacillus subtilis were synthesized or cloned and constructed into pETM6, an ePathBrick vector, which were then introduced into E. coli BL21star (DE3) separately. 20(R)-Protopanaxadiol (PPD), 20(R)-protopanaxatriol (PPT), and 20(R)-type ginsenosides were used as substrates for biotransformation with recombinant E. coli modified with those UGT genes. Results: E. coli engineered with $GT95^{syn}$ selectively transfers a glucose moiety to the C20 hydroxyl of 20(R)-PPD and 20(R)-PPT to produce 20(R)-CK and 20(R)-F1, respectively. GTK1- and GTC1-modified E. coli glycosylated the C3-OH of 20(R)-PPD to form 20(R)-Rh2. Moreover, E. coli containing $p2GT95^{syn}K1$, a recreated two-step glycosylation pathway via the ePathBrich, implemented the successive glycosylation at C20-OH and C3-OH of 20(R)-PPD and yielded 20(R)-F2 in the biotransformation broth. Conclusion: This study demonstrates that rare 20(R)-ginsenosides can be produced through E. coli engineered with UTG genes.
Ting Chen,Ming Yang,Hui Yang,Ruining Wang,Shujuan Wang,Hang Zhang,Xiaoyu Zhang,Zhijuan Zhao,Jinben Wang 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.69 No.-
Although nano “green” coatings with excellent corrosion resistance have attracted great attention, the inhibition efficiency is still limited due to the lack of knowledge about the correlation between molecular structure and anticorrosion performance. Here, we fabricated a series of 3,4-dihydroxy-l-phenylalanine adlayers on self-assembled monolayers (SAMs) with varying end groups. We found that both NH2 and CF3SAMs were more conducive to the adsorption of DOPA and a flat adsorption conformation was preferentially adopted, with the plane of the phenylene ring parallel to the surface via cation-π interactions or hydrophobic interactions, leading to a compact and dense adlayer. Such DOPA-SAM multilayers can effectively protect the substrate from corrosion by suppressing the diffusion of aggressive water and acid molecules as well as the electrodissolution of metals. The lowest corrosion current of adlayers reaches 6.96 μA cm−2 which is much lower than that of bare substrate and other anticorrosion surfaces reported previously. The results provide guidance on the design of green anticorrosion materials via selecting SAMs that bridge organic and metal interface.
Lu Yu,Yuan Chen,Jie Shi,Ru-Feng Wang,Ying-Bo Yang,Li Yang,Shujuan Zhao,Zheng-Tao Wang 고려인삼학회 2019 Journal of Ginseng Research Vol.43 No.1
Background: Ginsenosides are known as the principal pharmacological active constituents in Panax medicinal plants such as Asian ginseng, American ginseng, and Notoginseng. Some ginsenosides, especially the 20(R) isomers, are found in trace amounts in natural sources and are difficult to chemically synthesize. The present study provides an approach to produce such trace ginsenosides applying biotransformation through Escherichia coli modified with relevant genes. Methods: Seven uridine diphosphate glycosyltransferase (UGT) genes originating from Panax notoginseng, Medicago sativa, and Bacillus subtilis were synthesized or cloned and constructed into pETM6, an ePathBrick vector, which were then introduced into E. coli BL21star (DE3) separately. 20(R)-Protopanaxadiol (PPD), 20(R)-protopanaxatriol (PPT), and 20(R)-type ginsenosides were used as substrates for biotransformation with recombinant E. coli modified with those UGT genes. Results: E. coli engineered with GT95syn selectively transfers a glucose moiety to the C20 hydroxyl of 20(R)-PPD and 20(R)-PPT to produce 20(R)-CK and 20(R)-F1, respectively. GTK1- and GTC1-modified E. coli glycosylated the C3eOH of 20(R)-PPD to form 20(R)-Rh2. Moreover, E. coli containing p2GT95synK1, a recreated two-step glycosylation pathway via the ePathBrich, implemented the successive glycosylation at C20eOH and C3eOH of 20(R)-PPD and yielded 20(R)-F2 in the biotransformation broth. Conclusion: This study demonstrates that rare 20(R)-ginsenosides can be produced through E. coli engineered with UTG genes.