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1. chinaXiv:201608.00209 [pdf]

PMT overshoot study for JUNO prototype detector

Feng-Jiao Luo; Yue-Kun Heng; Zhi-Min Wang; Pei-Liang Wang; Zhong-Hua Qin; 2 Mei-Hang Xu; Dong-Hao Liao; Hai-Qiong Zhang; Yong-Bo Huang; Xiang-Cui Lei; Sen Qian; Shu-Lin Liu; Yuan-Bo Chen; Yi-Fang Wang
Subjects: Physics >> Nuclear Physics

The quality of PMT signal is one of the key items for a large and high precision neutrino experiment, like Daya Bay, JUNO, while most of the experiments are affected by the PMT signal overshoot from its positive HV-single cable scheme. For JUNO prototype detector, we have a detailed study on the PMT overshoot and successfully reduced the ratio of overshoot amplitude to signal to ~1% from previous typical ~10%, with no affection to PMT other parameters. Furthermore, we calculated that the overshoot is a result of discharging of capacitors in the HV-signal splitter and the PMT voltage divider. The study result is extremely important for JUNO and other similar experiments.

submitted time 2016-08-31 Hits1303Downloads738 Comment 0

2. chinaXiv:201605.01469 [pdf]

Dynamic Phosphorylation of CENP-A at Ser68 Orchestrates Its Cell-Cycle-Dependent Deposition at Centromeres

Yu, Zhouliang; Zhou, Xiang; Wang, Wenjing; Deng, Wenqiang; Fang, Junnan; Hu, Hao; Wang, Zichen; Cui, Lei; Shen, Jing; Ou, Guangshuo; Yang, Na; Chen, Ping; Xu, Rui-Ming; Li, Guohong; Yu, Zhouliang; Deng, Wenqiang; Fang, Junnan; Hu, Hao; Peng, Shengyi; Li, Shangze
Subjects: Biology >> Biophysics >> Cell Biology

The H3 histone variant CENP-A is an epigenetic marker critical for the centromere identity and function. However, the precise regulation of the spatiotemporal deposition and propagation of CENP-A at centromeres during the cell cycle is still poorly understood. Here, we show that CENP-A is phosphorylated at Ser68 during early mitosis by Cdk1. Our results demonstrate that phosphorylation of Ser68 eliminates the binding of CENP-A to the assembly factor HJURP, thus preventing the premature loading of CENP-A to the centromere prior to mitotic exit. Because Cdk1 activity is at its minimum at the mitotic exit, the ratio of Cdk1/PP1 alpha activity changes in favor of Ser68 dephosphorylation, thus making CENP-A available for centromeric deposition by HJURP. Thus, we reveal that dynamic phosphorylation of CENP-A Ser68 orchestrates the spatiotemporal assembly of newly synthesized CENP-A at active centromeres during the cell cycle.

submitted time 2016-05-12 Hits2584Downloads1491 Comment 0

3. chinaXiv:201605.01324 [pdf]

Molecular characteristics and evolutionary analysis of a very virulent infectious bursal disease virus

Li Zan; Zhu Ping; Qi XiaoLe; Ren XianGang; Wang XiaoMei; Cui Lei; Li Zan
Subjects: Biology >> Biophysics >> Biology

Infectious bursal disease virus (IBDV) poses a significant threat to the poultry industry. Viral protein 2 (VP2), the major structural protein of IBDV, has been subjected to frequent mutations that have imparted tremendous genetic diversity to the virus. To determine how amino acid mutations may affect the virulence of IBDV, we built a structural model of VP2 of a very virulent strain of IBDV identified in China, vvIBDV Gx, and performed a molecular dynamics simulation of the interaction between virulence sites. The study showed that the amino acid substitutions that distinguish vvIBDV from attenuated IBDV (H253Q and T284A) favor a hydrophobic and flexible conformation of beta-barrel loops in VP2, which could promote interactions between the virus and potential IBDV-specific receptors. Population sequence analysis revealed that the IBDV strains prevalent in East Asia show a significant signal of positive selection at virulence sites 253 and 284. In addition, a signal of co-evolution between sites 253 and 284 was identified. These results suggest that changes in the virulence of IBDV may result from both the interaction and the co-evolution of multiple amino acid substitutions at virulence sites.

submitted time 2016-05-11 Hits2575Downloads1414 Comment 0

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