分类： 核科学技术 >> 核材料与工艺技术 提交时间： 2024-02-20
摘要： The synergistic damage effect of irradiation and corrosion of reactor structural materials has been a prominent research focus. This paper provides a comprehensive review of the synergistic effects on the third- and fourth-generation fission nuclear energy structural materials used in pressurized water reactors and molten salt reactors. The competitive mechanisms of multiple influencing factors, such as the irradiation dose, corrosion type, and environmental temperature, are summarized in this paper. Conceptual approaches are proposed to alleviate the synergistic damage caused by irradiation and corrosion, thereby promoting in-depth research in the future and solving this key challenge for the structural materials used in reactors.
分类： 生物学 >> 生物物理学 >> 生物物理、生物化学与分子生物学 提交时间： 2016-05-11
Liu, Lian
Zhang, Shao-Wu
Zhang, Yu-Chen
Chen, Runsheng
Liu, Hui
Zhang, Lin
Chen, Runsheng
Huang, Yufei
Meng, Jia
摘要： Biochemical modifications to mRNA, especially N6-methyladenosine (m(6)A) and 5-methylcytosine (m(5)C), have been recently shown to be associated with crucial biological functions. Despite the intriguing advancements, little is known so far about the dynamic landscape of RNA methylome across different cell types and how the epitranscriptome is regulated at the system level by enzymes, i.e., RNA methyltransferases and demethylases. To investigate this issue, a meta-analysis of m(6)A MeRIP-Seq datasets collected from 10 different experimental conditions (cell type/tissue or treatment) is performed, and the combinatorial epitranscriptome, which consists of 42758 m(6)A sites, is extracted and divided into 3 clusters, in which the methylation sites are likely to be hyper- or hypo-methylated simultaneously (or co-methylated), indicating the sharing of a common methylation regulator. Four different clustering approaches are used, including K-means, hierarchical clustering (HC), Bayesian factor regression model (BFRM) and nonnegative matrix factorization (NMF) to unveil the co-methylation patterns. To validate whether the patterns are corresponding to enzymatic regulators, i.e., RNA methyltransferases or demethylases, the target sites of a known m(6)A regulator, fat mass and obesity-associated protein (FTO), are identified from an independent mouse MeRIP-Seq dataset and lifted to human. Our study shows that 3 out of the 4 clustering approaches used can successfully identify a group of methylation sites overlapping with FTO target sites at a significance level of 0.05 (after multiple hypothesis adjustment), among which, the result of NMF is the most significant (p-value 2.81 x 10(-06)). We defined a new approach evaluating the consistency between two clustering results which shows that clustering results of different methods are highly correlated strongly indicating the existence of co-methylation patterns. Consistent with recent studies, a number of cancer and neuronal disease-related bimolecular functions are enriched in the identified clusters, which are biological functions that can be regulated at the epitranscriptional level, indicating the pharmaceutical prospect of RNA N6-methyladenosine-related studies. This result successfully reveals the linkage between the global RNA co-methylation patterns embedded in the epitranscriptomic data under multiple experimental conditions and the latent enzymatic regulators, suggesting a promising direction towards a more comprehensive understanding of the epitranscriptome.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Jake Clark
Brett Addison
Jack Okumura
Sydney Vach
Alexis Heitzmann
Joseph Rodriguez
Duncan Wright
Mathieu Clerte
Carolyn Brown
Tara Fetherolf
Robert Wittenmyer
Peter Plavchan
Stephen Kane
Jonathan Horner
John Kielkopf
Avi Shporer
C. Tinney
Liu Hui-Gen
Sarah Ballard
Brendan Bowler
摘要： NASA's Transiting Exoplanet Survey Satellite (TESS) mission, has been uncovering a growing number of exoplanets orbiting nearby, bright stars. Most exoplanets that have been discovered by TESS orbit narrow-line, slow-rotating stars, facilitating the confirmation and mass determination of these worlds. We present the discovery of a hot Jupiter orbiting a rapidly rotating ($v\sin{(i)}= 35.1\pm1.0$km/s) early F3V-dwarf, HD115447 (TOI-778). The transit signal taken from Sectors 10 and 37 of TESS's initial detection of the exoplanet is combined with follow-up ground-based photometry and velocity measurements taken from Minerva-Australis, TRES, CORALIE and CHIRON to confirm and characterise TOI-778b. A joint analysis of the light curves and the radial velocity measurements yield a mass, radius, and orbital period for TOI-778b of $2.76^{+0.24}_{-0.23}$Mjup, $1.370\pm0.043$Rjup and $\sim4.63$ days, respectively. The planet orbits a bright ($V = 9.1$mag) F3-dwarf with $M=1.40\pm0.05$Msun, $R=1.70\pm0.05$Rsun, and $\log g=4.05\pm0.17$. We observed a spectroscopic transit of TOI-778b, which allowed us to derive a sky-projected spin-orbit angle of $18^{\circ}\pm11^{\circ}$, consistent with an aligned planetary system. This discovery demonstrates the capability of smaller aperture telescopes such as Minerva-Australis to detect the radial velocity signals produced by planets orbiting broad-line, rapidly rotating stars.
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