1 Multipotent peripheral glial cells generate neuroendocrine cells of the adrenal medulla
Alessandro Furlan, Vyacheslav Dyachuk, Maria Eleni Kastriti…Patrik Ernfors, Igor Adameyko
（导读 卓思琪）肾上腺中，嗜铬细胞是分泌肾上腺素的主要神经内分泌细胞。传统观点认为嗜铬细胞由神经嵴细胞分化而来，而本文发现很多嗜铬细胞是由周围神经胶质细胞——施万细胞前体（Schwann cell precursors，SCPs)分化产生的。SCPs延内脏运动神经迁移至发育中的肾上腺附近后，分化为嗜铬细胞。这一分化过程对肾上腺的发育是重要的，说明周围神经是神经分泌系统发育的干细胞巢。
Adrenaline is a fundamental circulating hormone for bodily responses to internal and external stressors. Chromaffin cells of the adrenal medulla (AM) represent the main neuroendocrine adrenergic component and are believed to differentiate from neural crest cells. We demonstrate that large numbers of chromaffin cells arise from peripheral glial stem cells, termed Schwann cell precursors (SCPs). SCPs migrate along the visceral motor nerve to the vicinity of the forming adrenal gland, where they detach from the nerve and form postsynaptic neuroendocrine chromaffin cells. An intricate molecular logic drives two sequential phases of gene expression, one unique for a distinct transient cellular state and another for cell type specification. Subsequently, these programs down-regulate SCP-gene and up-regulate chromaffin cell–gene networks. The AM forms through limited cell expansion and requires the recruitment of numerous SCPs. Thus, peripheral nerves serve as a stem cell niche for neuroendocrine system development.
2 Cognitive science in the field: A preschool intervention durably enhances intuitive but not formal mathematics
Moira R. Dillon, Harini Kannan, Joshua T. Dean, Elizabeth S. Spelke, Esther Duflo
Many poor children are underprepared for demanding primary school curricula. Research in cognitive science suggests that school achievement could be improved by preschool pedagogy in which numerate adults engage children’s spontaneous, nonsymbolic mathematical concepts. To test this suggestion, we designed and evaluated a game-based preschool curriculum intended to exercise children’s emerging skills in number and geometry. In a randomized field experiment with 1540 children (average age 4.9 years) in 214 Indian preschools, 4 months of math game play yielded marked and enduring improvement on the exercised intuitive abilities, relative to no-treatment and active control conditions. Math-trained children also showed immediate gains on symbolic mathematical skills but displayed no advantage in subsequent learning of the language and concepts of school mathematics.
3 Origins of lymphatic and distant metastases in human colorectal cancer
Kamila Naxerova, Johannes G. Reiter, Elena Brachtel…Stephen J. Elledge, Rakesh K. Jain
The spread of cancer cells from primary tumors to regional lymph nodes is often associated with reduced survival. One prevailing model to explain this association posits that fatal, distant metastases are seeded by lymph node metastases. This view provides a mechanistic basis for the TNM staging system and is the rationale for surgical resection of tumor-draining lymph nodes. Here we examine the evolutionary relationship between primary tumor, lymph node, and distant metastases in human colorectal cancer. Studying 213 archival biopsy samples from 17 patients, we used somatic variants in hypermutable DNA regions to reconstruct high-confidence phylogenetic trees. We found that in 65% of cases, lymphatic and distant metastases arose from independent subclones in the primary tumor, whereas in 35% of cases they shared common subclonal origin. Therefore, two different lineage relationships between lymphatic and distant metastases exist in colorectal cancer.
4 Quantized electric multipole insulators
Wladimir A. Benalcazar, B. Andrei Bernevig, Taylor L. Hughes
The Berry phase provides a modern formulation of electric polarization in crystals. We extend this concept to higher electric multipole moments and determine the necessary conditions and minimal models for which the quadrupole and octupole moments are topologically quantized electromagnetic observables. Such systems exhibit gapped boundaries that are themselves lower-dimensional topological phases. Furthermore, they host topologically protected corner states carrying fractional charge, exhibiting fractionalization at the boundary of the boundary.（翻译可能不准确，边界的边界，指的应该是能隙种被填充部分的边界）To characterize these insulating phases of matter, we introduce a paradigm in which “nested” Wilson loops give rise to topological invariants that have been overlooked. We propose three realistic experimental implementations of this topological behavior that can be immediately tested. Our work opens a venue for the expansion of the classification of topological phases of matter.
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5 Nanoscale nuclear magnetic resonance with chemical resolution
Nabeel Aslam, Matthias Pfender, Philipp Neumann…Junichi Isoya, Jörg Wrachtrup
Nuclear magnetic resonance (NMR) spectroscopy is a key analytical technique in chemistry, biology, and medicine. However, conventional NMR spectroscopy requires an at least nanoliter-sized sample volume to achieve sufficient signal. We combined the use of a quantum memory and high magnetic fields with a dedicated quantum sensor based on nitrogen vacancy centers in diamond to achieve chemical shift resolution in 1H and 19F NMR spectroscopy of 20-zeptoliter sample volumes. We demonstrate the application of NMR pulse sequences to achieve homonuclear decoupling and spin diffusion measurements. The best measured NMR linewidth of a liquid sample was ~1 part per million, mainly limited by molecular diffusion. To mitigate the influence of diffusion, we performed high-resolution solid-state NMR by applying homonuclear decoupling and achieved a 20-fold narrowing of the NMR linewidth.
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6.Femtosecond electron-phonon lock-in by photoemission and x-ray free-electron laser
S. Gerber, S.-L. Yang, D. Zhu…P. S. Kirchmann, Z.-X. Shen
The interactions that lead to the emergence of superconductivity in iron-based materials remain a subject of debate. It has been suggested that electron-electron correlations enhance electron-phonon coupling in iron selenide (FeSe) and related pnictides, but direct experimental verification has been lacking. Here we show that the electron-phonon coupling strength in FeSe can be quantified by combining two time-domain experiments into a “coherent lock-in” measurement in the terahertz regime. X-ray diffraction tracks the light-induced femtosecond coherent lattice motion at a single phonon frequency, and photoemission monitors the subsequent coherent changes in the electronic band structure. Comparison with theory reveals a strong enhancement of the coupling strength in FeSe owing to correlation effects. Given that the electron-phonon coupling affects superconductivity exponentially, this enhancement highlights the importance of the cooperative interplay between electron-electron and electron-phonon interactions.
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7 Discovery of orbital-selective Cooper pairing in FeSe
P. O. Sprau, A. Kostin, A. Kreisel…B. M. Andersen, J. C. Séamus Davis
（导读：阿金）硒化铁（FeSe）因其异常的非磁性向列相和潜在的高温超导性，一直吸引着学术界的强烈研究兴趣。本研究使用Bogoliubov准粒子干涉成像测量了FeSe三维费米面结构以及相应的超导带隙。结果显示Γ 和X 带隙表现为各向异性、没有节点、且在动量空间中正交。带隙的排布结构揭示了FeSe中具有轨道选择性的库珀对的存在。
The superconductor iron selenide (FeSe) is of intense interest owing to its unusual nonmagnetic nematic state and potential for high-temperature superconductivity. But its Cooper pairing mechanism has not been determined. We used Bogoliubov quasiparticle interference imaging to determine the Fermi surface geometry of the electronic bands surrounding the Γ = (0, 0) and X = (π/aFe, 0) points of FeSe and to measure the corresponding superconducting energy gaps. We show that both gaps are extremely anisotropic but nodeless and that they exhibit gap maxima oriented orthogonally in momentum space. Moreover, by implementing a novel technique, we demonstrate that these gaps have opposite sign with respect to each other. This complex gap configuration reveals the existence of orbital-selective Cooper pairing that, in FeSe, is based preferentially on electrons from the dyz orbitals of the iron atoms.
8 Evolution of the wheat blast fungus through functional losses in a host specificity determinant
Yoshihiro Inoue, Trinh T. P. Vy, Kentaro Yoshida…Mark Farman, Yukio Tosa
Wheat blast first emerged in Brazil in the mid-1980s and has recently caused heavy crop losses in Asia. Here we show how this devastating pathogen evolved in Brazil. Genetic analysis of host species determinants in the blast fungus resulted in the cloning of avirulence genes PWT3 and PWT4, whose gene products elicit defense in wheat cultivars containing the corresponding resistance genes Rwt3 and Rwt4. Studies on avirulence and resistance gene distributions, together with historical data on wheat cultivation in Brazil, suggest that wheat blast emerged due to widespread deployment of rwt3 wheat (susceptible to Lolium isolates), followed by the loss of function of PWT3. This implies that the rwt3 wheat served as a springboard for the host jump to common wheat.
9 Neurodevelopmental protein Musashi-1 interacts with the Zika genome and promotes viral replication
Pavithra L. Chavali, Lovorka Stojic, Luke W. Meredith…C. Geoffrey Woods, Fanni Gergely
A recent outbreak of Zika virus in Brazil has led to a simultaneous increase in reports of neonatal microcephaly. Zika targets cerebral neural precursors, a cell population essential for cortical development, but the cause of this neurotropism remains obscure. Here we report that the neural RNA-binding protein Musashi-1 (MSI1) interacts with the Zika genome and enables viral replication. Zika infection disrupts the binding of MSI1 to its endogenous targets, thereby deregulating expression of factors implicated in neural stem cell function. We further show that MSI1 is highly expressed in neural progenitors of the human embryonic brain and is mutated in individuals with autosomal recessive primary microcephaly. Selective MSI1 expression in neural precursors could therefore explain the exceptional vulnerability of these cells to Zika infection.
10 Citywide effects of high-occupancy vehicle restrictions: Evidence from “three-in-one” in Jakarta
Rema Hanna, Gabriel Kreindler, Benjamin A. Olken
（导读 刘威尔）本研究以雅加达的“一车三人（three-in-one）”政策（要求私人车辆在高峰时期主干道上必须搭乘3人以上）为例，通过手机谷歌地图交通速度数据，调查高承载车辆（high-occupancy vehicle, HOV）相关政策对交通拥堵的影响。早、晚高峰的延误时间在政策废止后分别由2.1和2.8分钟每千米上升至3.1和5.3分钟每千米，表明HOV政策能够显著改善交通状况。
Widespread use of single-occupancy cars often leads to traffic congestion. Using anonymized traffic speed data from Android phones collected through Google Maps, we investigated whether high-occupancy vehicle (HOV) policies can combat congestion. We studied Jakarta’s “three-in-one” policy, which required all private cars on two major roads to carry at least three passengers during peak hours. After the policy was abruptly abandoned in April 2016, delays rose from 2.1 to 3.1 minutes per kilometer (min/km) in the morning peak and from 2.8 to 5.3 min/km in the evening peak. The lifting of the policy led to worse traffic throughout the city, even on roads that had never been restricted or at times when restrictions had never been in place. In short, we find that HOV policies can greatly improve traffic conditions.
11 Wild emmer genome architecture and diversity elucidate wheat evolution and domestication
Raz Avni, Moran Nave, Omer Barad…Eduard D. Akhunov, Assaf Distelfeld
Wheat (Triticum spp.) is one of the founder crops that likely drove the Neolithic transition to sedentary agrarian societies in the Fertile Crescent more than 10,000 years ago. Identifying genetic modifications underlying wheat’s domestication requires knowledge about the genome of its allo-tetraploid progenitor, wild emmer (T. turgidum ssp. dicoccoides). We report a 10.1-gigabase assembly of the 14 chromosomes of wild tetraploid wheat, as well as analyses of gene content, genome architecture, and genetic diversity. With this fully assembled polyploid wheat genome, we identified the causal mutations in Brittle Rachis 1 (TtBtr1) genes controlling shattering, a key domestication trait. A study of genomic diversity among wild and domesticated accessions revealed genomic regions bearing the signature of selection under domestication. This reference assembly will serve as a resource for accelerating the genome-assisted improvement of modern wheat varieties.
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