《自然》（20181122出版）一周論文導讀

Nature,Volume 563 Issue 7732, 22 November 2018

《自然》2018年11月22日第7732期563卷

航空學Aviation

Flight of anaeroplanewith solid-state propulsion

採用固體推進系統的飛機

作者：Haofeng Xu、Yiou He、Kieran L. Strobel、Christopher K. Gilmore、Steven R. H. Barrett，et al

鏈接：

https://www.nature.com/articles/s41586-018-0707-9

摘要：

本論文描述了一架採用固體推進系統的小型飛機的飛行，這使得製造更安靜、機械更簡單且不產生燃燒排放的飛機成為可能。

一直以來，飛行器的動力來自帶有活動部件的發動機，例如推進器或渦輪機，並且通常依靠化石燃料燃燒。有人提出採用電空氣動力學裝置——通過電力加速流體中的離子以形成離子風產生推力，可作為推進飛行器的一種替代方法。

研究人員設計了一架帶有電空氣動力推進系統的小型固定翼飛機，並進行了試飛。該飛機重2.45千克，翼展5米，依靠定製系統提供動力。定製動力系統包含一個電池組和高壓電源轉換器，輸出功率約500瓦。

在10次試飛中，飛機在室內空間成功飛行了60米，平均飛行高度為0.47米。儘管整體效率較低，但是其推功比與傳統推進系統（如噴氣發動機）相當。

這種特殊的飛機設計優先考慮的是小機型而不是高效率，但未來的設計可以提高效率。

Abstract

Since the first aeroplane flight more than 100 years ago, aeroplanes have been propelled using moving surfaces such as propellers and turbines. Most have been powered by fossil-fuel combustion. Electroaerodynamics, in which electrical forces accelerate ions in a fluid, has been proposed as an alternative method of propelling aeroplanes—without moving parts, nearly silently and without combustion emissions. However, no aeroplane with such a solid-state propulsion system has yet flown. Here we demonstrate that a solid-state propulsion system can sustain powered flight, by designing and flying an electroaerodynamically propelled heavier-than-air aeroplane. We flew a fixed-wing aeroplane with a five-metre wingspan ten times and showed that it achieved steady-level flight. All batteries and power systems, including a specifically developed ultralight high-voltage (40-kilovolt) power converter, were carriedon-board. We show that conventionally accepted limitations in thrust-to-power ratio and thrust density, which were previously thought to make electroaerodynamics unfeasible as a method of aeroplane propulsion, are surmountable. We provide a proof of concept for electroaerodynamic aeroplane propulsion, opening up possibilities for aircraft and aerodynamic devices that are quieter, mechanically simpler and do not emit combustion emissions.

地球科學Geoscience

Twentieth-century contribution to sea-levelrise fromuncharted glaciers

20世紀海平面上升「貢獻者」包括未知冰川

作者：David Parkes、Ben Marzeion

鏈接：

https://www.nature.com/articles/s41586-018-0687-9

摘要：

20世紀全球平均海平面上升（GMSLR）主要是由冰川和冰蓋的質量損失、海水的熱膨脹和陸地蓄水能力的變化引起的。

然而，無論是基於觀測還是氣候模型結果，這些貢獻的估計總和往往低於觀測到的GMSLR。

這裡，研究人員發現從1901年到2015年，錯漏和消失的冰川產生了大約16.7到48.0毫米的海平面當量（SLE）。

其中，缺失的冰川是那些人們期望今天仍存在的小冰川，但由於區域分析和理論比例關係，這些冰川並沒有反映在冰川資料庫中，而它們大約貢獻了12.3到42.7毫米的歷史SLE。

此外，消失的冰川（1901年存在，但到2015年已經融化的冰川，因此也不在資料庫單中）估計貢獻了4.4到5.3毫米。

Abstract

Global-mean sea-level rise (GMSLR) during the twentieth century was primarily caused by glacier and ice-sheet mass loss, thermal expansion of ocean water and changes in terrestrial water storage. Whether based on observations or results of climate models, however, the sum of estimates of each of these contributions tends to fall short of the observed GMSLR. Current estimates of the glacier contribution to GMSLR rely on the analysis of glacier inventory data, which are known to undersample the smallest glacier size classes. Here we show that from 1901 to 2015, missing and disappeared glaciers produced a sea-level equivalent (SLE) of approximately16.7 to 48.0 millimetres. Missing glaciers are those small glaciers that we expect to exist today, owing to regional analyses and theoretical scaling relationships, but that are not represented in the inventories. These glaciers contributed approximately 12.3 to 42.7 millimetres to the historical SLE.Additionally, disappeared glaciers (those that existed in 1901 but had melted away by 2015, and that therefore cannot be included in modern global glacier inventories) made an estimated contribution of between 4.4 and 5.3 millimetres. Failure to consider these uncharted glaciers may be an important cause of difficulties in closing the GMSLR budget during the twentieth century: their contribution is on average between 0.17 and 0.53 millimetres of SLE per year, compared to a budget discrepancy of about 0.5 millimetres of GMSLR per year between 1901 and 1990. Although the uncharted glaciers will have a minimal role in sea-level rise in the future, and are less important after 1990, these findings imply that undiscovered physical processes are not required to close the historical sea-level budget.

生物學Biology

Improved referencegenome of Aedes aegypti informs arbovirus vector control

改良埃及伊蚊基因組助力蟲媒控制研究

作者：Benjamin J. Matthews、Olga Dudchenko、Leslie B. Vosshall，et al

鏈接：

https://www.nature.com/articles/s41586-018-0692-z

摘要：

埃及伊蚊每年感染4億多人，能傳播登革熱病毒、黃熱病病毒、寨卡病毒和基孔肯亞熱病毒等多種病毒。

由於缺乏高質量的基因組數據，人們在了解蚊子的生物學特性和開發對抗工具方面的進展放緩。

此次，研究人員將各種技術結合起來，生產出顯著改進的、完全重新注釋的AaegL5基因組集合，並演示了它如何加速了蚊子研究。

研究人員鎖定了物理和細胞遺傳學圖譜，將已知的引導蚊子到人類宿主和產卵位點的化學感受器數量增加了一倍，進一步了解了決定蚊子性別的M位點的大小和組成，並揭示了谷胱甘肽s—轉移酶基因變異，而谷胱甘肽s—轉移酶基因對殺蟲劑抗性至關重要。

研究人員還繪製出登革熱病蟲媒能力和殺蟲劑抗性的新候選基因。AaegL5將促進新的生物學見解和干預策略，以對抗這種致命的疾病載體。

Abstract

Female Aedesaegypti mosquitoes infect more than 400 million people each year with dangerous viral pathogens including dengue, yellow fever, Zika and chikungunya. Progress in understanding the biology of mosquitoes and developing the tools to fight them has been slowed by the lack of a high-quality genome assembly. Here we combine diverse technologies to produce the markedly improved, fully re-annotated AaegL5 genome assembly, and demonstrate how it accelerates mosquito science. We anchored physical and cytogenetic maps, doubled the number of known chemosensory ionotropic receptors that guide mosquitoes to human hosts and egg-laying sites, provided further insight into the size and composition of the sex-determining M locus, and revealed copy-number variation among glutathione S-transferase genes that are important for insecticide resistance. Using high-resolution quantitative trait locus and population genomic analyses, we mapped new candidates for dengue vector competence and insecticide resistance. AaegL5 will catalyse new biological insights and intervention strategies to fight this deadly disease vector.

TDP-43 and RNA form amyloid-likemyo-granules in regenerating muscle

TDP-43和RNA在肌肉再生過程中形成澱粉樣肌粒

作者：Thomas O. Vogler、Joshua R. Wheeler、Eric D. Nguyen、Kyla A. Britson、Aaron M. Johnson、Bradley B. Olwin、Roy Parker，et al

鏈接：

https://www.nature.com/articles/s41586-018-0665-2

摘要：

神經肌肉疾病（包括肌萎縮性脊髓側索硬化症和包涵體肌病）的主要組織病理學特徵是RNA結合蛋白TDP-43的細胞質聚集。

雖然TARDBP（編碼TDP-43的基因）的罕見突變通常會導致蛋白質的錯誤摺疊，但大多數患者並沒有出現TARDBP突變。

但野生型TDP-43在大多數患者中以一種未知的機制出現。在這裡，研究人員證明TDP-43是正常骨骼肌形成的必要蛋白，在小鼠和人類骨骼肌再生過程中，它能形成肌粒。

肌粒與編碼肌節蛋白的mRNA結合，並隨著肌纖維成熟而清除。雖然肌粒出現在正常的骨骼肌再生過程中，但肌粒可以在體外播散TDP-43澱粉樣纖維，並在包涵體肌病的小鼠模型中增加。

因此，肌粒聚合增加或清除減少可能是神經肌肉疾病中常見的TDP-43聚集物的來源。

Abstract

A dominant histopathological feature in neuromuscular diseases, including amyotrophic lateral sclerosis and inclusion body myopathy, is cytoplasmic aggregation of the RNA-binding protein TDP-43. Although rare mutations in TARDBP—the gene that encodes TDP-43—that lead to protein misfolding often cause protein aggregation, most patients do not have any mutations in TARDBP. Therefore, aggregates of wild-type TDP-43 arise in most patients by an unknown mechanism. Here we show that TDP-43 is an essential protein for normal skeletal muscle formation that unexpectedly forms cytoplasmic, amyloid-like oligomeric assemblies, which we call myo-granules, during regeneration of skeletal muscle in mice and humans. Myo-granules bind to mRNAs that encode sarcomeric proteins and are cleared as myofibres mature. Although myo-granules occur during normal skeletal-muscle regeneration, myo-granules can seed TDP-43 amyloid fibrils in vitro and are increased in a mouse model of inclusion body myopathy. Therefore, increased assembly or decreased clearance of functionally normal myo-granules could be the source of cytoplasmic TDP-43 aggregates that commonly occur in neuromuscular disease.

Mannose impairstumourgrowth and enhances chemotherapy

甘露糖能損害腫瘤生長增強化療效果

作者：Pablo Sierra Gonzalez、James O』Prey、Simone Cardaci、Valentin J. A. Barthet、Kevin M. Ryan，et al

鏈接：

https://www.nature.com/articles/s41586-018-0729-3

摘要：

許多腫瘤會經歷代謝變化，表現出葡萄糖攝取增加，由此引出了一個問題：服用不同類型的糖能否影響腫瘤生長。

研究人員通過飼管（一周三次）和飲水（持續性地）讓腫瘤小鼠服用甘露糖。結果顯示這種療法耐受良好，而且無論單獨施用還是結合阿黴素施用，似乎都減緩了腫瘤生長。

細胞對甘露糖的敏感性與較低水平的磷酸甘露糖異構酶（PMI）相關。研究人員測試了不同人類腫瘤細胞（卵巢癌、腎癌、乳腺癌、前列腺癌和結直腸癌）中的PMI水平，結果參差不齊。

其中，結直腸腫瘤的PMI水平較低，這意味著它們可能對甘露糖更敏感。這項研究前景可觀，但是仍需要進一步的研究加以驗證。

Abstract

It is now well established that tumours undergo changes in cellular metabolism. As this can reveal tumour cell vulnerabilities and because many tumours exhibit enhanced glucose uptake, we have been interested in how tumour cells respond to different forms of sugar. Here we report that the monosaccharide mannose causes growth retardation in several tumour types in vitro, and enhances cell death in response to major forms of chemotherapy. We then show that these effects also occur in vivo in mice following the oral administration of mannose, without significantly affecting the weight and health of the animals. Mechanistically, mannose is taken up by the same transporter(s) as glucose3 but accumulates as mannose-6-phosphate in cells, and this impairs the further metabolism of glucose in glycolysis, the tricarboxylic acid cycle, the pentose phosphate pathway and glycan synthesis. As a result, the administration of mannose in combination with conventional chemotherapy affects levels of anti-apoptotic proteins of the Bcl-2 family, leading to sensitization to cell death. Finally we show that susceptibility to mannose is dependent on the levels of phospho mannose isomerase (PMI). Cells with low levels of PMI are sensitive to mannose, whereas cells with high levels are resistant, but can be made sensitive by RNA-interference-mediated depletion of the enzyme. In addition, we use tissue microarrays to show that PMI levels also vary greatly between different patients and different tumour types, indicating that PMI levels could be used as a biomarker to direct the successful administration of mannose. We consider that the administration of mannose could be a simple, safe and selective therapy in the treatment of cancer, and could be applicable to multiple tumour types.

化學Chemistry

Efficient radical-based light-emitting diodes with doublet emission

雙激子高效自由基發光二極體

作者：Xin Ai、Emrys W. Evans、Shengzhi Dong、Feng Li，et al

鏈接：

https://www.nature.com/articles/s41586-018-0695-9

摘要：

有機發光二極體（OLED）、基於量子點的LED、基於鈣鈦礦的LED和微LED一直被認為是適用於下一代顯示器和主動式照明的輕型和柔性單元。

雖然目前已經有一些基於OLED的高端商業產品，但成本居高不下。

在這裡，研究人員演示了自由基OLED的有效作用，它們的發射源是自旋雙激子，而不是單激子或三激子。雖然在這些OLED中發射過程仍然允許自旋，但效率限制性被規避。

通過使用發光自由基發射器，研究人員演示了在710納米的波長下，最大外部量子效率為27%的OLED，這是深紅色和紅外LED的最高報告值。

Abstract

Organic light-emitting diodes (OLEDs)quantum-dot-based LEDs, perovskite-based LEDs and micro-LEDs have been championed to fabricate lightweight and flexible units for next-generation displays and active lighting. Although there are already some high-end commercial products based on OLEDs, costs must decrease whilst maintaining high operational efficiencies for the technology to realise wider impact. Here we demonstrate efficient action of radical-based OLEDs, whose emission originates from a spin doublet, rather than a singlet or triplet exciton. While the emission process is still spin-allowed in these OLEDs, the efficiency limitations imposed by triplet excitons are circumvented for doublets. Using a luminescent radical emitter, we demonstrate an OLED with maximum external quantum efficiency of 27 per cent at a wavelength of 710 nanometres—the highest reported value for deep-red and infrared LEDs. For a standard closed-shell organic semiconductor, holes and electrons occupy the highest occupied and lowest unoccupied molecular orbitals (HOMOs and LUMOs), respectively, and recombine to form singlet ortriplet excitons. Radical emitters have a singly occupied molecular orbital(SOMO) in the ground state, giving an overall spin-1/2 doublet. If—as expected on energetic grounds—both electrons and holes occupy this SOMO level, recombination returns the system to the ground state, giving no light emission. However, in our very efficient OLEDs, we achieve selective hole injection into the HOMO and electron injection to the SOMO to form the fluorescent doublet excited state with near-unity internal quantum efficiency.

Enhanced strengthand ductility in a high-entropy alloy via ordered oxygen complexes

通過有序氧複合物增強高熵合金的強度和延展性

作者：Zhifeng Lei、Xiongjun Liu、Yuan Wu、Hui Wang、Zhaoping Lu，et al

鏈接：

https://www.nature.com/articles/s41586-018-0685-y

摘要：

氧是地球上最豐富的元素之一，通常會在金屬材料中形成一種不需要的間隙雜質或陶瓷相（如氧化物顆粒），而氧摻雜物會使金屬變得脆弱。

這裡研究展示了氧能以有序的氧複合物的形式出現，這是一種介於氧化物顆粒和隨機間質之間的狀態。

與傳統的間隙強化不同的是，這種有序的間隙複合物使得複雜固溶體即高熵合金的強度和延展性都得到了前所未有的提高。

抗拉強度提高（48.5±1.8%）和延展性大幅改善（95.2±8.1%）打破了長期以來強度—延展性權衡。這些結果使人們對金屬材料有序強化機制的作用有了更深入了解。

Abstract

Oxygen, one of the most abundant elements on Earth, often forms an undesired interstitial impurity or ceramic phase (such as an oxide particle) in metallic materials. Even when it adds strength, oxygen doping renders metals brittle. Here we show that oxygen can take the form of ordered oxygen complexes, a state in between oxide particles and frequently occurring random interstitials. Unlike traditional interstitial strengthening, such ordered interstitial complexes lead to unprecedented enhancement in both strength and ductility in compositionally complex solid solutions, the so-called high-entropy alloys(HEAs). The tensile strength is enhanced (by 48.5 ± 1.8 percent) and ductility is substantially improved (by 95.2 ± 8.1 percent) when doping a model TiZrHfNbHEA with 2.0 atomic percent oxygen, thus breaking the long-standing strength–ductility trade-off. The oxygen complexes are ordered nanoscale regions within the HEA characterized by (O, Zr, Ti)-rich atomic complexes whose formation is promoted by the existence of chemical short-range ordering among some of the substitutional matrix elements in the HEAs. Carbon has been reported to improve strength and ductility simultaneously in face-centred cubicHEAs, by lowering the stacking fault energy and increasing the lattice friction stress. By contrast, the ordered interstitial complexes described here change the dislocation shear mode from planar slip to wavy slip, and promote doublecross-slip and thus dislocation multiplication through the formation ofFrank–Read sources (a mechanism explaining the generation of multiple dislocations) during deformation. This ordered interstitial complex-mediated strain-hardening mechanism should be particularly useful in Ti-, Zr- and Hf-containing alloys, in which interstitial elements are highly undesirable owing to their embrittlement effects, and in alloys where tuning the stacking fault energy and exploiting athermal transformations do not lead to property enhancement. These results provide insight into the role of interstitial solid solutions and associated ordering strengthening mechanisms in metallic materials.

（唐一塵）

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