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英国评估工业CCUS的供应链能力和经济增长机遇 快报文章
气候变化快报,2023年第16期
作者:  王田宇,刘燕飞
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CCUS  Supply Chain  Industrial Emissions  Process Control  Market Investment  
Coupling delay controls synchronized oscillation in the segmentation clock 期刊论文
NATURE, 2020
作者:  Yoshioka-Kobayashi, Kumiko;  Matsumiya, Marina;  Niino, Yusuke;  Isomura, Akihiro;  Kori, Hiroshi;  Miyawaki, Atsushi;  Kageyama, Ryoichiro
收藏  |  浏览/下载:8/0  |  提交时间:2020/07/03

Individual cellular activities fluctuate but are constantly coordinated at the population level via cell-cell coupling. A notable example is the somite segmentation clock, in which the expression of clock genes (such as Hes7) oscillates in synchrony between the cells that comprise the presomitic mesoderm (PSM)(1,2). This synchronization depends on the Notch signalling pathway  inhibiting this pathway desynchronizes oscillations, leading to somite fusion(3-7). However, how Notch signalling regulates the synchronicity of HES7 oscillations is unknown. Here we establish a live-imaging system using a new fluorescent reporter (Achilles), which we fuse with HES7 to monitor synchronous oscillations in HES7 expression in the mouse PSM at a single-cell resolution. Wild-type cells can rapidly correct for phase fluctuations in HES7 oscillations, whereas the absence of the Notch modulator gene lunatic fringe (Lfng) leads to a loss of synchrony between PSM cells. Furthermore, HES7 oscillations are severely dampened in individual cells of Lfng-null PSM. However, when Lfng-null PSM cells were completely dissociated, the amplitude and periodicity of HES7 oscillations were almost normal, which suggests that LFNG is involved mostly in cell-cell coupling. Mixed cultures of control and Lfng-null PSM cells, and an optogenetic Notch signalling reporter assay, revealed that LFNG delays the signal-sending process of intercellular Notch signalling transmission. These results-together with mathematical modelling-raised the possibility that Lfng-null PSM cells shorten the coupling delay, thereby approaching a condition known as the oscillation or amplitude death of coupled oscillators(8). Indeed, a small compound that lengthens the coupling delay partially rescues the amplitude and synchrony of HES7 oscillations in Lfng-null PSM cells. Our study reveals a delay control mechanism of the oscillatory networks involved in somite segmentation, and indicates that intercellular coupling with the correct delay is essential for synchronized oscillation.


Monitoring cells of the mouse presomitic mesoderm using the Achilles reporter fused to HES7 sheds light on the mechanisms that underpin synchronous oscillations in the expression of clock genes between neighbouring cells.


  
Brain control of humoral immune responses amenable to behavioural modulation 期刊论文
NATURE, 2020, 581 (7807)
作者:  Yang, C. H.;  Leon, R. C. C.;  Hwang, J. C. C.;  Saraiva, A.;  Tanttu, T.;  Huang, W.;  Lemyre, J. Camirand;  Chan, K. W.;  Tan, K. Y.;  Hudson, F. E.;  Itoh, K. M.;  Morello, A.;  Pioro-Ladriere, M.;  Laucht, A.;  Dzurak, A. S.
收藏  |  浏览/下载:12/0  |  提交时间:2020/07/03

It has been speculated that brain activities might directly control adaptive immune responses in lymphoid organs, although there is little evidence for this. Here we show that splenic denervation in mice specifically compromises the formation of plasma cells during a T cell-dependent but not T cell-independent immune response. Splenic nerve activity enhances plasma cell production in a manner that requires B-cell responsiveness to acetylcholine mediated by the alpha 9 nicotinic receptor, and T cells that express choline acetyl transferase(1,2) probably act as a relay between the noradrenergic nerve and acetylcholine-responding B cells. We show that neurons in the central nucleus of the amygdala (CeA) and the paraventricular nucleus (PVN) that express corticotropin-releasing hormone (CRH) are connected to the splenic nerve  ablation or pharmacogenetic inhibition of these neurons reduces plasma cell formation, whereas pharmacogenetic activation of these neurons increases plasma cell abundance after immunization. In a newly developed behaviour regimen, mice are made to stand on an elevated platform, leading to activation of CeA and PVN CRH neurons and increased plasma cell formation. In immunized mice, the elevated platform regimen induces an increase in antigen-specific IgG antibodies in a manner that depends on CRH neurons in the CeA and PVN, an intact splenic nerve, and B cell expression of the alpha 9 acetylcholine receptor. By identifying a specific brain-spleen neural connection that autonomically enhances humoral responses and demonstrating immune stimulation by a bodily behaviour, our study reveals brain control of adaptive immunity and suggests the possibility to enhance immunocompetency by behavioural intervention.


Neuronal activities in the central amygdala and paraventricular nucleus are transmitted via the splenic nerve to increase plasma cell formation after immunization, and this process can be behaviourally enhanced in mice.


  
Non-volatile electric control of spin-charge conversion in a SrTiO3 Rashba system 期刊论文
NATURE, 2020, 580 (7804) : 483-+
作者:  Collombet, Samuel;  Ranisavljevic, Noemie;  Nagano, Takashi;  Varnai, Csilla;  Shisode, Tarak;  Leung, Wing;  Piolot, Tristan;  Galupa, Rafael;  Borensztein, Maud;  Servant, Nicolas;  Fraser, Peter;  Ancelin, Katia;  Heard, Edith
收藏  |  浏览/下载:15/0  |  提交时间:2020/07/03

The polarization direction of a ferroelectric-like state can be used to control the conversion of spin currents into charge currents at the surface of strontium titanate, a non-magnetic oxide.


After 50 years of development, the technology of today'  s electronics is approaching its physical limits, with feature sizes smaller than 10 nanometres. It is also becoming clear that the ever-increasing power consumption of information and communication systems(1) needs to be contained. These two factors require the introduction of non-traditional materials and state variables. As recently highlighted(2), the remanence associated with collective switching in ferroic systems is an appealing way to reduce power consumption. A promising approach is spintronics, which relies on ferromagnets to provide non-volatility and to generate and detect spin currents(3). However, magnetization reversal by spin transfer torques(4) is a power-consuming process. This is driving research on multiferroics to achieve low-power electric-field control of magnetization(5), but practical materials are scarce and magnetoelectric switching remains difficult to control. Here we demonstrate an alternative strategy to achieve low-power spin detection, in a non-magnetic system. We harness the electric-field-induced ferroelectric-like state of strontium titanate (SrTiO3)(6-9) to manipulate the spin-orbit properties(10) of a two-dimensional electron gas(11), and efficiently convert spin currents into positive or negative charge currents, depending on the polarization direction. This non-volatile effect opens the way to the electric-field control of spin currents and to ultralow-power spintronics, in which non-volatility would be provided by ferroelectricity rather than by ferromagnetism.


  
Paracrine orchestration of intestinal tumorigenesis by a mesenchymal niche 期刊论文
NATURE, 2020, 580 (7804) : 524-+
作者:  Poore, Gregory D.;  Kopylova, Evguenia;  Zhu, Qiyun;  Carpenter, Carolina;  Fraraccio, Serena;  Wandro, Stephen;  Kosciolek, Tomasz;  Janssen, Stefan;  Metcalf, Jessica;  Song, Se Jin;  Kanbar, Jad;  Miller-Montgomery, Sandrine;  Heaton, Robert;  Mckay, Rana;  Patel, Sandip Pravin;  Swafford, Austin D.;  Knight, Rob
收藏  |  浏览/下载:40/0  |  提交时间:2020/07/03

The initiation of an intestinal tumour is a probabilistic process that depends on the competition between mutant and normal epithelial stem cells in crypts(1). Intestinal stem cells are closely associated with a diverse but poorly characterized network of mesenchymal cell types(2,3). However, whether the physiological mesenchymal microenvironment of mutant stem cells affects tumour initiation remains unknown. Here we provide in vivo evidence that the mesenchymal niche controls tumour initiation in trans. By characterizing the heterogeneity of the intestinal mesenchyme using single-cell RNA-sequencing analysis, we identified a population of rare pericryptal Ptgs2-expressing fibroblasts that constitutively process arachidonic acid into highly labile prostaglandin E-2 (PGE(2)). Specific ablation of Ptgs2 in fibroblasts was sufficient to prevent tumour initiation in two different models of sporadic, autochthonous tumorigenesis. Mechanistically, single-cell RNA-sequencing analyses of a mesenchymal niche model showed that fibroblast-derived PGE(2) drives the expansion omicron f a population of Sca-1(+) reserve-like stem cells. These express a strong regenerative/tumorigenic program, driven by the Hippo pathway effector Yap. In vivo, Yap is indispensable for Sca-1(+) cell expansion and early tumour initiation and displays a nuclear localization in both mouse and human adenomas. Using organoid experiments, we identified a molecular mechanism whereby PGE(2) promotes Yap dephosphorylation, nuclear translocation and transcriptional activity by signalling through the receptor Ptger4. Epithelial-specific ablation of Ptger4 misdirected the regenerative reprogramming of stem cells and prevented Sca-1(+) cell expansion and sporadic tumour initiation in mutant mice, thereby demonstrating the robust paracrine control of tumour-initiating stem cells by PGE(2)-Ptger4. Analyses of patient-derived organoids established that PGE(2)-PTGER4 also regulates stem-cell function in humans. Our study demonstrates that initiation of colorectal cancer is orchestrated by the mesenchymal niche and reveals a mechanism by which rare pericryptal Ptgs2-expressing fibroblasts exert paracrine control over tumour-initiating stem cells via the druggable PGE(2)-Ptger4-Yap signalling axis.


Single-cell RNA-sequencing analysis of intestinal mesenchyme identified a population of fibroblasts that produce prostaglandin E-2, which, when disrupted, prevented initiation of intestinal tumours.


  
General synthesis of two-dimensional van der Waals heterostructure arrays 期刊论文
NATURE, 2020: 368-+
作者:  Bloch, Joel S.;  Pesciullesi, Giorgio;  Boilevin, Jeremy;  Nosol, Kamil;  Irobalieva, Rossitza N.;  Darbre, Tamis;  Aebi, Markus;  Kossiakoff, Anthony A.;  Reymond, Jean-Louis;  Locher, Kaspar P.
收藏  |  浏览/下载:63/0  |  提交时间:2020/07/03

Two-dimensional van der Waals heterostructures (vdWHs) have attracted considerable interest(1-4). However, most vdWHs reported so far are created by an arduous micromechanical exfoliation and manual restacking process(5), which-although versatile for proof-of-concept demonstrations(6-16) and fundamental studies(17-30)-is clearly not scalable for practical technologies. Here we report a general synthetic strategy for two-dimensional vdWH arrays between metallic transition-metal dichalcogenides (m-TMDs) and semiconducting TMDs (s-TMDs). By selectively patterning nucleation sites on monolayer or bilayer s-TMDs, we precisely control the nucleation and growth of diverse m-TMDs with designable periodic arrangements and tunable lateral dimensions at the predesignated spatial locations, producing a series of vdWH arrays, including VSe2/WSe2, NiTe2/WSe2, CoTe2/WSe2, NbTe2/WSe2, VS2/WSe2, VSe2/MoS2 and VSe2/WS2. Systematic scanning transmission electron microscopy studies reveal nearly ideal vdW interfaces with widely tunable moire superlattices. With the atomically clean vdW interface, we further show that the m-TMDs function as highly reliable synthetic vdW contacts for the underlying WSe2 with excellent device performance and yield, delivering a high ON-current density of up to 900 microamperes per micrometre in bilayer WSe2 transistors. This general synthesis of diverse two-dimensional vdWH arrays provides a versatile material platform for exploring exotic physics and promises a scalable pathway to high-performance devices.


A general strategy for the synthesis of two-dimensional van der Waals heterostructure arrays is used to produce high-performance electronic devices, showing the potential of this scalable approach for practical technologies.


  
Current-driven magnetic domain-wall logic 期刊论文
NATURE, 2020, 579 (7798) : 214-+
作者:  Culp, Elizabeth J.;  Waglechner, Nicholas;  Wang, Wenliang;  Fiebig-Comyn, Aline A.;  Hsu, Yen-Pang;  Koteva, Kalinka;  Sychantha, David;  Coombes, Brian K.;  Van Nieuwenhze, Michael S.;  Brun, Yves, V;  Wright, Gerard D.
收藏  |  浏览/下载:31/0  |  提交时间:2020/07/03

Spin-based logic architectures provide nonvolatile data retention, near-zero leakage, and scalability, extending the technology roadmap beyond complementary metal-oxide-semiconductor logic(1-13). Architectures based on magnetic domain walls take advantage of the fast motion, high density, non-volatility and flexible design of domain walls to process and store information(1,3,14-16). Such schemes, however, rely on domain-wall manipulation and clocking using an external magnetic field, which limits their implementation in dense, large-scale chips. Here we demonstrate a method for performing all-electric logic operations and cascading using domain-wall racetracks. We exploit the chiral coupling between neighbouring magnetic domains induced by the interfacial Dzyaloshinskii-Moriya interaction(17-20), which promotes non-collinear spin alignment, to realize a domain-wall inverter, the essential basic building block in all implementations of Boolean logic. We then fabricate reconfigurable NAND and NOR logic gates, and perform operations with current-induced domain-wall motion. Finally, we cascade several NAND gates to build XOR and full adder gates, demonstrating electrical control of magnetic data and device interconnection in logic circuits. Our work provides a viable platform for scalable all-electric magnetic logic, paving the way for memory-in-logic applications.


  
Synthesis of rare sugar isomers through site-selective epimerization 期刊论文
NATURE, 2020: 403-+
作者:  Jackson, Hartland W.;  Fischer, Jana R.;  Zanotelli, Vito R. T.;  Ali, H. Raza;  Mechera, Robert;  Soysal, Savas D.;  Moch, Holger;  Muenst, Simone;  Varga, Zsuzsanna;  Weber, Walter P.;  Bodenmiller, Bernd
收藏  |  浏览/下载:15/0  |  提交时间:2020/07/03

Glycans have diverse physiological functions, ranging from energy storage and structural integrity to cell signalling and the regulation of intracellular processes(1). Although biomass-derived carbohydrates (such as d-glucose, d-xylose and d-galactose) are extracted on commercial scales, and serve as renewable chemical feedstocks and building blocks(2,3), there are hundreds of distinct monosaccharides that typically cannot be isolated from their natural sources and must instead be prepared through multistep chemical or enzymatic syntheses(4,5). These '  rare'  sugars feature prominently in bioactive natural products and pharmaceuticals, including antiviral, antibacterial, anticancer and cardiac drugs(6,7). Here we report the preparation of rare sugar isomers directly from biomass carbohydrates through site-selective epimerization reactions. Mechanistic studies establish that these reactions proceed under kinetic control, through sequential steps of hydrogen-atom abstraction and hydrogen-atom donation mediated by two distinct catalysts. This synthetic strategy provides concise and potentially extensive access to this valuable class of natural compounds.


Various rare sugars that cannot be isolated from natural sources are synthesized using light-driven epimerization, a process which may find application in other synthetic scenarios.


  
Wafer-scale single-crystal hexagonal boron nitride monolayers on Cu (111) 期刊论文
NATURE, 2020, 579 (7798) : 219-+
作者:  Luong, Duy X.;  Bets, Ksenia V.;  Algozeeb, Wala Ali;  Stanford, Michael G.;  Kittrell, Carter;  Chen, Weiyin;  Salvatierra, Rodrigo V.;  Ren, Muqing;  McHugh, Emily A.;  Advincula, Paul A.;  Wang, Zhe;  Bhatt, Mahesh;  Guo, Hua;  Mancevski, Vladimir;  Shahsavari, Rouzbeh
收藏  |  浏览/下载:81/0  |  提交时间:2020/07/03

Ultrathin two-dimensional (2D) semiconducting layered materials offer great potential for extending Moore'  s law of the number of transistors in an integrated circuit(1). One key challenge with 2D semiconductors is to avoid the formation of charge scattering and trap sites from adjacent dielectrics. An insulating van der Waals layer of hexagonal boron nitride (hBN) provides an excellent interface dielectric, efficiently reducing charge scattering(2,3). Recent studies have shown the growth of single-crystal hBN films on molten gold surfaces(4) or bulk copper foils(5). However, the use of molten gold is not favoured by industry, owing to its high cost, cross-contamination and potential issues of process control and scalability. Copper foils might be suitable for roll-to-roll processes, but are unlikely to be compatible with advanced microelectronic fabrication on wafers. Thus, a reliable way of growing single-crystal hBN films directly on wafers would contribute to the broad adoption of 2D layered materials in industry. Previous attempts to grow hBN monolayers on Cu (111) metals have failed to achieve mono-orientation, resulting in unwanted grain boundaries when the layers merge into films(6,7). Growing single-crystal hBN on such high-symmetry surface planes as Cu (111)(5,8) is widely believed to be impossible, even in theory. Nonetheless, here we report the successful epitaxial growth of single-crystal hBN monolayers on a Cu (111) thin film across a two-inch c-plane sapphire wafer. This surprising result is corroborated by our first-principles calculations, suggesting that the epitaxial growth is enhanced by lateral docking of hBN to Cu (111) steps, ensuring the mono-orientation of hBN monolayers. The obtained single-crystal hBN, incorporated as an interface layer between molybdenum disulfide and hafnium dioxide in a bottom-gate configuration, enhanced the electrical performance of transistors. This reliable approach to producing wafer-scale single-crystal hBN paves the way to future 2D electronics.


  
Hidden diversity of vacancy networks in Prussian blue analogues 期刊论文
NATURE, 2020, 578 (7794) : 256-+
作者:  Hendrickx, N. W.;  Franke, D. P.;  Sammak, A.;  Scappucci, G.;  Veldhorst, M.
收藏  |  浏览/下载:15/0  |  提交时间:2020/07/03

Prussian blue analogues (PBAs) are a diverse family of microporous inorganic solids, known for their gas storage ability(1), metal-ion immobilization(2), proton conduction(3), and stimuli-dependent magnetic(4,5), electronic(6) and optical(7) properties. This family of materials includes the double-metal cyanide catalysts(8,9) and the hexacyanoferrate/ hexacyanomanganate battery materials(10,11). Central to the various physical properties of PBAs is their ability to reversibly transport mass, a process enabled by structural vacancies. Conventionally presumed to be random(12,13), vacancy arrangements are crucial because they control micropore-network characteristics, and hence the diffusivity and adsorption profiles(14,15). The long-standing obstacle to characterizing the vacancy networks of PBAs is the inaccessibility of single crystals(16). Here we report the growth of single crystals of various PBAs and the measurement and interpretation of their X-ray diffuse scattering patterns. We identify a diversity of non-random vacancy arrangements that is hidden from conventional crystallographic powder analysis. Moreover, we explain this unexpected phase complexity in terms of a simple microscopic model that is based on local rules of electroneutrality and centrosymmetry. The hidden phase boundaries that emerge demarcate vacancynetwork polymorphs with very different micropore characteristics. Our results establish a foundation for correlated defect engineering in PBAs as a means of controlling storage capacity, anisotropy and transport efficiency.