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search.filters.applied.f.access: openAccess × DDC: 570 × Publisher: Washington, DC [u.a.] : Assoc. ×

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    Gold-DNA nanosunflowers for efficient gene silencing with controllable transformation
    (Washington, DC [u.a.] : Assoc., 2019) Huo, Shuaidong; Gong, Ningqiang; Jiang, Ying; Chen, Fei; Guo, Hongbo; Gan, Yaling; Wang, Zhisen; Herrmann, Andreas; Liang, Xing-Jie
    The development of an efficient delivery system for enhanced and controlled gene interference–based therapeutics is still facing great challenges. Fortunately, the flourishing field of nanotechnology provides more effective strategies for nucleic acid delivery. Here, the triplex-forming oligonucleotide sequence and its complementary strand were used to mediate self-assembly of ultrasmall gold nanoparticles. The obtained sunflower-like nanostructures exhibited strong near-infrared (NIR) absorption and photothermal conversion ability. Upon NIR irradiation, the large-sized nanostructure could disassemble and generate ultrasmall nanoparticles modified with c-myc oncogene silencing sequence, which could directly target the cell nucleus. Moreover, the controlled gene silencing effect could be realized by synergistically controlling the preincubation time with the self-assembled nanostructure (in vitro and in vivo) and NIR irradiation time point. This study provides a new approach for constructing more efficient and tailorable nanocarriers for gene interference applications
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    Spatial variations in crop growing seasons pivotal to reproduce global fluctuations in maize and wheat yields
    (Washington, DC [u.a.] : Assoc., 2018) Jägermeyr, Jonas; Frieler, Katja
    Testing our understanding of crop yield responses to weather fluctuations at global scale is notoriously hampered by limited information about underlying management conditions, such as cultivar selection or fertilizer application. Here, we demonstrate that accounting for observed spatial variations in growing seasons increases the variance in reported national maize and wheat yield anomalies that can be explained by process-based model simulations from 34 to 58% and 47 to 54% across the 10 most weather-sensitive main producers, respectively. For maize, the increase in explanatory power is similar to the increase achieved by accounting for water stress, as compared to simulations assuming perfect water supply in both rainfed and irrigated agriculture. Representing water availability constraints in irrigation is of second-order importance. We improve the model’s explanatory power by better representing crops’ exposure to observed weather conditions, without modifying the weather response itself. This growing season adjustment now allows for a close reproduction of heat wave and drought impacts on crop yields.
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    Projected changes in persistent extreme summer weather events: The role of quasi-resonant amplification
    (Washington, DC [u.a.] : Assoc., 2018) Mann, Michael E.; Rahmstorf, Stefan; Kornhuber, Kai; Steinman, Byron A.; Miller, Sonya K.; Petri, Stefan; Coumou, Dim
    Persistent episodes of extreme weather in the Northern Hemisphere summer have been associated with highamplitude quasi-stationary atmospheric Rossby waves, with zonal wave numbers 6 to 8 resulting from the phenomenon of quasi-resonant amplification (QRA). A fingerprint for the occurrence of QRA can be defined in terms of the zonally averaged surface temperature field. Examining state-of-the-art [Coupled Model Intercomparison Project Phase 5 (CMIP5)] climate model projections, we find that QRA events are likely to increase by ∼50% this century under business-as-usual carbon emissions, but there is considerable variation among climate models. Some predict a near tripling of QRA events by the end of the century, while others predict a potential decrease. Models with amplified Arctic warming yield the most pronounced increase in QRA events. The projections are strongly dependent on assumptions regarding the nature of changes in radiative forcing associated with anthropogenic aerosols over the next century. One implication of our findings is that a reduction in midlatitude aerosol loading could actually lead to Arctic de-amplification this century, ameliorating potential increases in persistent extreme weather events.