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Large local lattice expansion in graphene adlayers grown on copper
Chen, Chaoyu,Avila, José,Arezki, Hakim,Nguyen, Van Luan,Shen, Jiahong,Mucha-Kruczyń,ski, Marcin,Yao, Fei,Boutchich, Mohamed,Chen, Yue,Lee, Young Hee,Asensio, Maria C. Nature Publishing Group UK 2018 NATURE MATERIALS Vol.17 No.5
<P>Variations of the lattice parameter can significantly change the properties of a material, and, in particular, its electronic behaviour. In the case of graphene, however, variations of the lattice constant with respect to graphite have been limited to less than 2.5% due to its well-established high in-plane stiffness. Here, through systematic electronic and lattice structure studies, we report regions where the lattice constant of graphene monolayers grown on copper by chemical vapour deposition increases up to similar to 7.5% of its relaxed value. Density functional theory calculations confirm that this expanded phase is energetically metastable and driven by the enhanced interaction between the substrate and the graphene adlayer. We also prove that this phase possesses distinctive chemical and electronic properties. The inherent phase complexity of graphene grown on copper foils revealed in this study may inspire the investigation of possible metastable phases in other seemingly simple heterostructure systems.</P>
Retraction Note: Large local lattice expansion in graphene adlayers grown on copper
Chen, Chaoyu,Avila, José,Arezki, Hakim,Nguyen, Van Luan,Shen, Jiahong,Mucha-Kruczyń,ski, Marcin,Yao, Fei,Boutchich, Mohamed,Chen, Yue,Lee, Young Hee,Asensio, Maria C. Springer Science and Business Media LLC 2018 NATURE MATERIALS Vol.17 No.11
Detection of Rare Mutations in EGFR-ARMS-PCR-Negative Lung Adenocarcinoma by Sanger Sequencing
Chaoyue Liang,Zhuolin Wu,Xiaohong Gan,Yuanbin Liu,You You,Chenxian Liu,Chengzhi Zhou,Ying Liang,Haiyun Mo,Allen M. Chen,Jiexia Zhang 연세대학교의과대학 2018 Yonsei medical journal Vol.59 No.1
Purpose: This study aimed to identify potential epidermal growth factor receptor (EGFR) gene mutations in non-small cell lung cancer that went undetected by amplification refractory mutation system-Scorpion real-time PCR (ARMS-PCR). Materials and Methods: A total of 200 specimens were obtained from the First Affiliated Hospital of Guangzhou Medical University from August 2014 to August 2015. In total, 100 ARMS-negative and 100 ARMS-positive specimens were evaluated for EGFR gene mutations by Sanger sequencing. The methodology and sensitivity of each method and the outcomes of EGFR-tyrosine kinase inhibitor (TKI) therapy were analyzed. Results: Among the 100 ARMS-PCR-positive samples, 90 were positive by Sanger sequencing, while 10 cases were considered negative, because the mutation abundance was less than 10%. Among the 100 negative cases, three were positive for a rare EGFR mutation by Sanger sequencing. In the curative effect analysis of EGFR-TKIs, the progression-free survival (PFS) analysis based on ARMS and Sanger sequencing results showed no difference. However, the PFS of patients with a high abundance of EGFR mutationwas 12.4 months [95% confidence interval (CI), 11.6−12.4 months], which was significantly higher than that of patients with a low abundance of mutations detected by Sanger sequencing (95% CI, 10.7−11.3 months) (p<0.001). Conclusion: The ARMS method demonstrated higher sensitivity than Sanger sequencing, but was prone to missing mutations due to primer design. Sanger sequencing was able to detect rare EGFR mutations and deemed applicable for confirming EGFR status. A clinical trial evaluating the efficacy of EGFR-TKIs in patients with rare EGFR mutations is needed.
Yao Zhiming,Fan Jingyan,Dai Jun,Yu Chen,Zeng Han,Li Qingzhi,Hu Wei,Yan Chaoyue,Hao Meilin,Li Haotian,Li Shuo,Liu Jie,Huang Qi,Li Lu,Zhou Rui 한국미생물·생명공학회 2023 Journal of microbiology and biotechnology Vol.33 No.6
Tylosin is a potent veterinary macrolide antibiotic produced by the fermentation of Streptomyces fradiae; however, it is necessary to modify S. fradiae strains to improve tylosin production. In this study, we established a high-throughput, 24-well plate screening method for identifying S. fradiae strains that produce increased yields of tylosin. Additionally, we constructed mutant libraries of S. fradiae via ultraviolet (UV) irradiation and/or sodium nitrite mutagenesis. A primary screening of the libraries in 24-well plates and UV spectrophotometry identified S. fradiae mutants producing increased yields of tylosin. Mutants with tylosin yield 10% higher than the wild-type strain were inoculated into shake flasks, and the tylosin concentrations produced were determined by highperformance liquid chromatography (HPLC). Joint (UV irradiation and sodium nitrite) mutagenesis resulted in higher yields of mutants with enhanced tylosin production. Finally, 10 mutants showing higher tylosin yield were re-screened in shake flasks. The yield of tylosin A by strains UN-C183 (6767.64 ± 82.43 μg/ml) and UN-C137 (6889.72 ± 70.25 μg/ml) was significantly higher than that of the wild-type strain (6617.99 ± 22.67 μg/ml). These mutant strains will form the basis for further strain breeding in tylosin production.