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Anthropogenic and biogenic hydrophobic VOCs detected in clouds at the puy de Dome station using Stir Bar Sorptive Extraction: Deviation from the Henry's law prediction 期刊论文
ATMOSPHERIC RESEARCH, 2020, 237
作者:  Wang, Miao;  Perroux, Helene;  Fleuret, Jennifer;  Bianco, Angelica;  Bouvier, Laetitia;  Colomb, Aurelie;  Borbon, Agnes;  Deguillaume, Laurent
收藏  |  浏览/下载:18/0  |  提交时间:2020/07/02
Volatile organic compounds (VOCs)  Cloud  Gas-liquid partitioning  Henry'  s law  PUY station  Stir Bar Sorptive Extraction (SBSE)  
Recycling and metabolic flexibility dictate life in the lower oceanic crust 期刊论文
NATURE, 2020, 579 (7798) : 250-+
作者:  Zhou, Peng;  Yang, Xing-Lou;  Wang, Xian-Guang;  Hu, Ben;  Zhang, Lei;  Zhang, Wei;  Si, Hao-Rui;  Zhu, Yan;  Li, Bei;  Huang, Chao-Lin;  Chen, Hui-Dong;  Chen, Jing;  Luo, Yun;  Guo, Hua;  Jiang, Ren-Di;  Liu, Mei-Qin;  Chen, Ying;  Shen, Xu-Rui;  Wang, Xi;  Zheng, Xiao-Shuang;  Zhao, Kai;  Chen, Quan-Jiao;  Deng, Fei;  Liu, Lin-Lin;  Yan, Bing;  Zhan, Fa-Xian;  Wang, Yan-Yi;  Xiao, Geng-Fu;  Shi, Zheng-Li
收藏  |  浏览/下载:69/0  |  提交时间:2020/05/13

The lithified lower oceanic crust is one of Earth'  s last biological frontiers as it is difficult to access. It is challenging for microbiota that live in marine subsurface sediments or igneous basement to obtain sufficient carbon resources and energy to support growth(1-3) or to meet basal power requirements(4) during periods of resource scarcity. Here we show how limited and unpredictable sources of carbon and energy dictate survival strategies used by low-biomass microbial communities that live 10-750 m below the seafloor at Atlantis Bank, Indian Ocean, where Earth'  s lower crust is exposed at the seafloor. Assays of enzyme activities, lipid biomarkers, marker genes and microscopy indicate heterogeneously distributed and viable biomass with ultralow cell densities (fewer than 2,000 cells per cm(3)). Expression of genes involved in unexpected heterotrophic processes includes those with a role in the degradation of polyaromatic hydrocarbons, use of polyhydroxyalkanoates as carbon-storage molecules and recycling of amino acids to produce compounds that can participate in redox reactions and energy production. Our study provides insights into how microorganisms in the plutonic crust are able to survive within fractures or porous substrates by coupling sources of energy to organic and inorganic carbon resources that are probably delivered through the circulation of subseafloor fluids or seawater.


  
Layered nanocomposites by shear-flow-induced alignment of nanosheets 期刊论文
NATURE, 2020, 580 (7802) : 210-+
作者:  Rollie, Clare;  Chevallereau, Anne;  Watson, Bridget N. J.;  Chyou, Te-yuan;  Fradet, Olivier;  McLeod, Isobel;  Fineran, Peter C.;  Brown, Chris M.;  Gandon, Sylvain;  Westra, Edze R.
收藏  |  浏览/下载:68/0  |  提交时间:2020/07/03

Layered nanocomposites fabricated using a continuous and scalable process achieve properties exceeding those of natural nacre, the result of stiffened matrix polymer chains confined between highly aligned nanosheets.


Biological materials, such as bones, teeth and mollusc shells, are well known for their excellent strength, modulus and toughness(1-3). Such properties are attributed to the elaborate layered microstructure of inorganic reinforcing nanofillers, especially two-dimensional nanosheets or nanoplatelets, within a ductile organic matrix(4-6). Inspired by these biological structures, several assembly strategies-including layer-by-layer(4,7,8), casting(9,10), vacuum filtration(11-13) and use of magnetic fields(14,15)-have been used to develop layered nanocomposites. However, how to produce ultrastrong layered nanocomposites in a universal, viable and scalable manner remains an open issue. Here we present a strategy to produce nanocomposites with highly ordered layered structures using shear-flow-induced alignment of two-dimensional nanosheets at an immiscible hydrogel/oil interface. For example, nanocomposites based on nanosheets of graphene oxide and clay exhibit a tensile strength of up to 1,215 +/- 80 megapascals and a Young'  s modulus of 198.8 +/- 6.5 gigapascals, which are 9.0 and 2.8 times higher, respectively, than those of natural nacre (mother of pearl). When nanosheets of clay are used, the toughness of the resulting nanocomposite can reach 36.7 +/- 3.0 megajoules per cubic metre, which is 20.4 times higher than that of natural nacre  meanwhile, the tensile strength is 1,195 +/- 60 megapascals. Quantitative analysis indicates that the well aligned nanosheets form a critical interphase, and this results in the observed mechanical properties. We consider that our strategy, which could be readily extended to align a variety of two-dimensional nanofillers, could be applied to a wide range of structural composites and lead to the development of high-performance composites.


  
Elixirs for times of plague and bullion shortage 期刊论文
NATURE, 2020, 580 (7805) : 592-593
作者:  Gibney, Elizabeth
收藏  |  浏览/下载:21/0  |  提交时间:2020/07/03

The addition of a methyl group to a drug molecule can greatly alter the drug'  s pharmacological properties. A catalyst has been developed that enables this '  magic methyl effect'  to be rapidly explored for drug discovery.


Late-stage functionalization of complex organic molecules.


  
Actinide 2-metallabiphenylenes that satisfy Huckel's rule 期刊论文
NATURE, 2020, 578 (7796) : 563-+
作者:  Achar, Yathish Jagadheesh;  Adhil, Mohamood;  Choudhary, Ramveer;  Gilbert, Nick;  Foiani, Marco
收藏  |  浏览/下载:18/0  |  提交时间:2020/07/03

Aromaticity and antiaromaticity, as defined by Huckel'  s rule, are key ideas in organic chemistry, and are both exemplified in biphenylene(1-3)-a molecule that consists of two benzene rings joined by a four-membered ring at its core. Biphenylene analogues in which one of the benzene rings has been replaced by a different (4n + 2) pi-electron system have so far been associated only with organic compounds(4,5). In addition, efforts to prepare a zirconabiphenylene compound resulted in the isolation of a bis(alkyne) zirconocene complex instead(6). Here we report the synthesis and characterization of, to our knowledge, the first 2-metallabiphenylene compounds. Single-crystal X-ray diffraction studies reveal that these complexes have nearly planar, 11-membered metallatricycles with metrical parameters that compare well with those reported for biphenylene. Nuclear magnetic resonance spectroscopy, in addition to nucleus-independent chemical shift calculations, provides evidence that these complexes contain an antiaromatic cyclobutadiene ring and an aromatic benzene ring. Furthermore, spectroscopic evidence, Kohn-Sham molecular orbital compositions and natural bond orbital calculations suggest covalency and delocalization of the uranium f(2) electrons with the carbon-containing ligand.


The synthesis of uranium- and thorium-containing metallabiphenylenes demonstrates the ability of the actinides to stabilize aromatic/antiaromatic structures where transition metals have failed.


  
An orbital water-ice cycle on comet 67P from colour changes 期刊论文
NATURE, 2020, 578 (7793) : 49-+
作者:  Oh, Myoung Hwan;  Cho, Min Gee;  Chung, Dong Young;  Park, Inchul;  Kwon, Youngwook Paul;  Ophus, Colin;  Kim, Dokyoon;  Kim, Min Gyu;  Jeong, Beomgyun;  Gu, X. Wendy;  Jo, Jinwoung;  Yoo, Ji Mun;  Hong, Jaeyoung;  McMains, Sara;  Kang, Kisuk;  Sung, Yung-Eun;  Alivisatos, A. Paul;  Hyeon, Taeghwan
收藏  |  浏览/下载:85/0  |  提交时间:2020/07/03

Solar heating of a cometary surface provides the energy necessary to sustain gaseous activity, through which dust is removed(1,2). In this dynamical environment, both the coma(3,4) and the nucleus(5,6) evolve during the orbit, changing their physical and compositional properties. The environment around an active nucleus is populated by dust grains with complex and variegated shapes(7), lifted and diffused by gases freed from the sublimation of surface ices(8,9). The visible colour of dust particles is highly variable: carbonaceous organic material-rich grains(10) appear red while magnesium silicate-rich(11,12) and water-ice-rich(13,14) grains appear blue, with some dependence on grain size distribution, viewing geometry, activity level and comet family type. We know that local colour changes are associated with grain size variations, such as in the bluer jets made of submicrometre grains on comet Hale-Bopp(15) or in the fragmented grains in the coma(16) of C/1999 S4 (LINEAR). Apart from grain size, composition also influences the coma'  s colour response, because transparent volatiles can introduce a substantial blueing in scattered light, as observed in the dust particles ejected after the collision of the Deep Impact probe with comet 9P/Tempel 1(17). Here we report observations of two opposite seasonal colour cycles in the coma and on the surface of comet 67P/Churyumov-Gerasimenko through its perihelion passage(18). Spectral analysis indicates an enrichment of submicrometre grains made of organic material and amorphous carbon in the coma, causing reddening during the passage. At the same time, the progressive removal of dust from the nucleus causes the exposure of more pristine and bluish icy layers on the surface. Far from the Sun, we find that the abundance of water ice on the nucleus is reduced owing to redeposition of dust and dehydration of the surface layer while the coma becomes less red.


  
Nitrate addition stimulates microbial decomposition of organic matter in salt marsh sediments 期刊论文
GLOBAL CHANGE BIOLOGY, 2019, 25 (10) : 3224-3241
作者:  Bulseco, Ashley N.;  Giblin, Anne E.;  Tucker, Jane;  Murphy, Anna E.;  Sanderman, Jonathan;  Hiller-Bittrolff, Kenly;  Bowen, Jennifer L.
收藏  |  浏览/下载:32/0  |  提交时间:2019/11/27
16S rRNA gene  anaerobic respiration  decomposition  flow-through reactor  microbes  nitrate  organic matter  salt marsh  
2-day GCxGC Data Handling (Zoex GCImage) 会议
Milton Keynes, United Kingdom, 会议类型: Course;Workshop, 2017