Πέμπτη 30 Ιουλίου 2020

Rational synthesis of atomically precise graphene nanoribbons directly on metal oxide surfaces
Atomically precise graphene nanoribbons (GNRs) attract great interest because of their highly tunable electronic, optical, and transport properties. However, on-surface synthesis of GNRs is typically based on metal surface–assisted chemical reactions, where metallic substrates strongly screen their designer electronic properties and limit further applications. Here, we present an on-surface synthesis approach to forming atomically precise GNRs directly on semiconducting metal oxide surfaces. The...
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Thu Jul 30, 2020 20:39
News at a glance
Science: Current Issue
Thu Jul 30, 2020 20:39
A switch in time saves ligand
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Thu Jul 30, 2020 20:39
Wuhan coronavirus hunter Shi Zhengli speaks out
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Thu Jul 30, 2020 20:39
Graphene nanoribbons made on oxides
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Thu Jul 30, 2020 20:39
Global plan seeks to promote vaccine equity, spread risks
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Thu Jul 30, 2020 20:39
Boosted molecular mobility during common chemical reactions
Mobility of reactants and nearby solvent is more rapid than Brownian diffusion during several common chemical reactions when the energy release rate exceeds a threshold. Screening a family of 15 organic chemical reactions, we demonstrate the largest boost for catalyzed bimolecular reactions, click chemistry, ring-opening metathesis polymerization, and Sonogashira coupling. Boosted diffusion is also observed but to lesser extent for the uncatalyzed Diels-Alder reaction, but not for substitution reactions...
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Thu Jul 30, 2020 20:39
Hidden predictability in winds could improve climate forecasts
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Thu Jul 30, 2020 20:39
Structural insights into differences in G protein activation by family A and family B GPCRs
Family B heterotrimeric guanine nucleotide–binding protein (G protein)–coupled receptors (GPCRs) play important roles in carbohydrate metabolism. Recent structures of family B GPCR-Gs protein complexes reveal a disruption in the α-helix of transmembrane segment 6 (TM6) not observed in family A GPCRs. To investigate the functional impact of this structural difference, we compared the structure and function of the glucagon receptor (GCGR; family B) with the β2 adrenergic receptor (β2AR; family A)....
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Thu Jul 30, 2020 20:39
How an ancient microbial arms race remodeled human cells
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Thu Jul 30, 2020 20:39
Predicting large solar flares
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Thu Jul 30, 2020 20:39
Mountains and monsoons created Tibetan biodiversity
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Thu Jul 30, 2020 20:39
From my hand to your ears
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Thu Jul 30, 2020 20:39
This man can read letters but numbers are a blank
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Thu Jul 30, 2020 20:39
In-cell architecture of an actively transcribing-translating expressome
Structural biology studies performed inside cells can capture molecular machines in action within their native context. In this work, we developed an integrative in-cell structural approach using the genome-reduced human pathogen Mycoplasma pneumoniae. We combined whole-cell cross-linking mass spectrometry, cellular cryo–electron tomography, and integrative modeling to determine an in-cell architecture of a transcribing and translating expressome at subnanometer resolution. The expressome comprises...
Science: Current Issue
Thu Jul 30, 2020 20:39
Altered DNA base could play key role in pregnancy
Science: Current Issue
Thu Jul 30, 2020 20:39
A physics-based method that can predict imminent large solar flares
Solar flares are highly energetic events in the Sun’s corona that affect Earth’s space weather. The mechanism that drives the onset of solar flares is unknown, hampering efforts to forecast them, which mostly rely on empirical methods. We present the -scheme, a physics-based model to predict large solar flares through a critical condition of magnetohydrodynamic instability, triggered by magnetic reconnection. Analysis of the largest (X-class) flares from 2008 to 2019 (during solar cycle 24) shows...
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Thu Jul 30, 2020 20:39
Lizard man
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Thu Jul 30, 2020 20:39
Neocortex in the fetal brain
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Thu Jul 30, 2020 20:39
COVID-19 risks to global food security
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Thu Jul 30, 2020 20:39
Cleaner skies
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Thu Jul 30, 2020 20:39
Mapping the clean air haves and have-nots
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Thu Jul 30, 2020 20:39
A human immune system sans MAIT cells
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Thu Jul 30, 2020 20:39
Can we predict solar flares?
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Thu Jul 30, 2020 20:39
Inside the Paleolithic mind
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Thu Jul 30, 2020 20:39
Evolution of the human brain
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Thu Jul 30, 2020 20:39
ANGEL2 is a member of the CCR4 family of deadenylases with 2',3'-cyclic phosphatase activity
RNA molecules are frequently modified with a terminal 2',3'-cyclic phosphate group as a result of endonuclease cleavage, exonuclease trimming, or de novo synthesis. During pre-transfer RNA (tRNA) and unconventional messenger RNA (mRNA) splicing, 2',3'-cyclic phosphates are substrates of the tRNA ligase complex, and their removal is critical for recycling of tRNAs upon ribosome stalling. We identified the predicted deadenylase angel homolog 2 (ANGEL2) as a human phosphatase that converts 2',3'-cyclic...
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Thu Jul 30, 2020 20:39
Fine-tuning receptor-G protein activation and signaling
Science: Current Issue
Thu Jul 30, 2020 20:39
Human-specific ARHGAP11B increases size and folding of primate neocortex in the fetal marmoset
The neocortex has expanded during mammalian evolution. Overexpression studies in developing mouse and ferret neocortex have implicated the human-specific gene ARHGAP11B in neocortical expansion, but the relevance for primate evolution has been unclear. Here, we provide functional evidence that ARHGAP11B causes expansion of the primate neocortex. ARHGAP11B expressed in fetal neocortex of the common marmoset under control of the gene’s own (human) promoter increased the numbers of basal radial glia...
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Thu Jul 30, 2020 20:39
Ductile van der Waals materials
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Thu Jul 30, 2020 20:39
Allele-specific open chromatin in human iPSC neurons elucidates functional disease variants
Most neuropsychiatric disease risk variants are in noncoding sequences and lack functional interpretation. Because regulatory sequences often reside in open chromatin, we reasoned that neuropsychiatric disease risk variants may affect chromatin accessibility during neurodevelopment. Using human induced pluripotent stem cell (iPSC)–derived neurons that model developing brains, we identified thousands of genetic variants exhibiting allele-specific open chromatin (ASoC). These neuronal ASoCs were partially...
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Thu Jul 30, 2020 20:39
How does SARS-CoV-2 cause COVID-19?
Science: Current Issue
Thu Jul 30, 2020 20:39
Ancient orogenic and monsoon-driven assembly of the worlds richest temperate alpine flora
Understanding how alpine biotas formed in response to historical environmental change may improve our ability to predict and mitigate the threats to alpine species posed by global warming. In the world’s richest temperate alpine flora, that of the Tibet-Himalaya-Hengduan region, phylogenetic reconstructions of biome and geographic range evolution show that extant lineages emerged by the early Oligocene and diversified first in the Hengduan Mountains. By the early to middle Miocene, accelerated diversification...
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Thu Jul 30, 2020 20:39
William C. Dement (1928-2020)
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Thu Jul 30, 2020 20:39
My womb is my business
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Thu Jul 30, 2020 20:39
Confronting illness with empathy
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Thu Jul 30, 2020 20:39
Cautious optimism
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Thu Jul 30, 2020 20:39
Context is key to olfaction
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Thu Jul 30, 2020 20:39
Reactions give solvents a kick
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Thu Jul 30, 2020 20:39
China and India: Toward a sustainable world
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Thu Jul 30, 2020 20:39
Deformable semiconductors
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Thu Jul 30, 2020 20:39
Conservation needs a COVID-19 bailout
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Thu Jul 30, 2020 20:39
Epidemic in Northern California
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Thu Jul 30, 2020 20:39
Extinct-in-the-wild species' last stand
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Thu Jul 30, 2020 20:39
Lovastatin for cardiolaminopathy
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Thu Jul 30, 2020 20:39
Bonds between AAAS and Hubble span three decades
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Thu Jul 30, 2020 20:39
Shrubification of peatlands
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Thu Jul 30, 2020 20:39
Source of Stonehenge's sarsens
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Thu Jul 30, 2020 20:39
Too much of a good thing
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Thu Jul 30, 2020 20:39
This is the brain on probiotics
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Thu Jul 30, 2020 20:39
Autobiographical subnetworks
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Thu Jul 30, 2020 20:39
Simple swaps of CO2
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Thu Jul 30, 2020 20:39
Dimming Tucson's street lighting
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Thu Jul 30, 2020 20:39
Origins of an alpine flora
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Thu Jul 30, 2020 20:39
Human fetal microglia acquire homeostatic immune-sensing properties early in development
Microglia, immune cells of the central nervous system (CNS), are important for tissue development and maintenance and are implicated in CNS disease, but we lack understanding of human fetal microglia development. Single-cell gene expression and bulk chromatin profiles of microglia at 9 to 18 gestational weeks (GWs) of human fetal development were generated. Microglia were heterogeneous at all studied GWs. Microglia start to mature during this developmental period and increasingly resemble adult microglia...
Science: Current Issue
Thu Jul 30, 2020 20:39
The development of microglia
Science: Current Issue
Thu Jul 30, 2020 20:39
Exceptional plasticity in the bulk single-crystalline van der Waals semiconductor InSe
Inorganic semiconductors are vital for a number of critical applications but are almost universally brittle. Here, we report the superplastic deformability of indium selenide (InSe). Bulk single-crystalline InSe can be compressed by orders of magnitude and morphed into a Möbius strip or a simple origami at room temperature. The exceptional plasticity of this two-dimensional van der Waals inorganic semiconductor is attributed to the interlayer gliding and cross-layer dislocation slip that are mediated...
Science: Current Issue
Thu Jul 30, 2020 20:39
Integrative in-cell structural biology
Science: Current Issue
Thu Jul 30, 2020 20:39
Cooling and entangling ultracold atoms in optical lattices
Scalable, coherent many-body systems can enable the realization of previously unexplored quantum phases and have the potential to exponentially speed up information processing. Thermal fluctuations are negligible and quantum effects govern the behavior of such systems with extremely low temperature. We report the cooling of a quantum simulator with 10,000 atoms and mass production of high-fidelity entangled pairs. In a two-dimensional plane, we cool Mott insulator samples by immersing them into removable...
Science: Current Issue
Thu Jul 30, 2020 20:39
Secrets of a fast base editor
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Thu Jul 30, 2020 20:39
Direct reversible decarboxylation from stable organic acids in dimethylformamide solution
Many classical and emerging methodologies in organic chemistry rely on carbon dioxide (CO2) extrusion to generate reactive intermediates for bond-forming events. Synthetic reactions that involve the microscopic reverse—the carboxylation of reactive intermediates—have conventionally been undertaken using very different conditions. We report that chemically stable C(sp3) carboxylates, such as arylacetic acids and malonate half-esters, undergo uncatalyzed reversible decarboxylation in dimethylformamide...
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Thu Jul 30, 2020 20:39
Lowering the entropy
Science: Current Issue
Thu Jul 30, 2020 20:39
DNA capture by a CRISPR-Cas9-guided adenine base editor
CRISPR-Cas–guided base editors convert A•T to G•C, or C•G to T•A, in cellular DNA for precision genome editing. To understand the molecular basis for DNA adenosine deamination by adenine base editors (ABEs), we determined a 3.2-angstrom resolution cryo–electron microscopy structure of ABE8e in a substrate-bound state in which the deaminase domain engages DNA exposed within the CRISPR-Cas9 R-loop complex. Kinetic and structural data suggest that ABE8e catalyzes DNA deamination up to ~1100-fold faster...
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Thu Jul 30, 2020 20:39
How the thymus shaped immunology
Science: Current Issue
Thu Jul 30, 2020 20:39
Disparities in PM2.5 air pollution in the United States
Air pollution at any given time is unequally distributed across locations. Average concentrations of fine particulate matter smaller than 2.5 micrometers in diameter (PM2.5) have fallen over time. However, we do not know how the spatial distribution of PM2.5 has evolved. Here, we provide early evidence. We combine 36 years of PM2.5 concentrations measured over ~8.6 million grid cells with geographic, economic, and demographic data from ~65,000 U.S. census tracts. We show that differences in PM2.5...
Science: Current Issue
Thu Jul 30, 2020 20:39
How does COVID-19 develop?
Science: Current Issue
Thu Jul 30, 2020 20:39
Genomic surveillance reveals multiple introductions of SARS-CoV-2 into Northern California
The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread globally, with >365,000 cases in California as of 17 July 2020. We investigated the genomic epidemiology of SARS-CoV-2 in Northern California from late January to mid-March 2020, using samples from 36 patients spanning nine counties and the Grand Princess cruise ship. Phylogenetic analyses revealed the cryptic introduction of at least seven different SARS-CoV-2 lineages...
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Thu Jul 30, 2020 20:39
Revealing family differences
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Thu Jul 30, 2020 20:39
New Products
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Thu Jul 30, 2020 20:39
Deadenylating RNA molecules
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Thu Jul 30, 2020 20:39
The function of the thymus and its impact on modern medicine
The lymphoid system is intimately involved in immunological processes. The small lymphocyte that circulates through blood into lymphoid tissues, then through the lymph and back to the blood through the thoracic duct, is able to initiate immune responses after appropriate stimulation by antigen. However, the lymphocytes found in the thymus are deficient in this ability despite the fact that the thymus plays a central role in lymphocyte production and in ensuring the normal development of immunological...
Science: Current Issue
Thu Jul 30, 2020 20:39
Effects of allele-specific open chromatin
Science: Current Issue
Thu Jul 30, 2020 20:39
Erratum for the Report "Global distribution of earthworm diversity" by H. R. P. Phillips, C. A. Guerra, M. L. C. Bartz, M. J. I. Briones, G. Brown, T. W. Crowther, O. Ferlian, K. B. Gongalsky, J. van den Hoogen, J. Krebs, A. Orgiazzi, D. Routh, B. Schwarz, E. M. Bach, J. Bennett, U. Brose, T. Decaens, B. Konig-Ries, M. Loreau, J. Mathieu, C. Mulder, W. H. van der Putten, K. S. Ramirez, M. C. Rillig, D. Russell, M. Rutgers, M. P. Thakur, F. T. de Vries, D. H. Wall, D. A. Wardle, M. Arai, F. O. Ayuke, G. H. Baker, R. Beausejour, J. C. Bedano, K. Birkhofer, E. Blanchart, B. Blossey, T. Bolger, R. L. Bradley, M. A. Callaham, Y. Capowiez, M. E. Caulfield, A. Choi, F. V. Crotty, A. Davalos, D. J. Diaz Cosin, A. Dominguez, A. E. Duhour, N. van Eekeren, C. Emmerling, L. B. Falco, R. Fernandez, S. J. Fonte, C. Fragoso, A. L. C. Franco, M. Fugere, A. T. Fusilero, S. Gholami, M. J. Gundale, M. Gutierrez Lopez, D. K. Hackenberger, L. M. Hernandez, T. Hishi, A. R. Holdsworth, M. Holmstrup, K. N. Hopfensperger, E. Huerta Lwanga, V. Huhta, T. T. Hurisso, B. V. Iannone III, M. Iordache, M. Joschko, N. Kaneko, R. Kanianska, A. M. Keith, C. A. Kelly, M. L. Kernecker, J. Klaminder, A. W. Kone, Y. Kooch, S. T. Kukkonen, H. Lalthanzara, D. R. Lammel, I. M. Lebedev, Y. Li, J. B. Jesus Lidon, N. K. Lincoln, S. R. Loss, R. Marichal, R. Matula, J. H. Moos, G. Moreno, A. Moron-Rios, B. Muys, J. Neirynck, L. Norgrove, M. Novo, V. Nuutinen, V. Nuzzo, M. Rahman P, J. Pansu, S. Paudel, G. Peres, L. Perez-Camacho, R. Pineiro, J.-F. Ponge, M. I. Rashid, S. Rebollo, J. Rodeiro-Iglesias, M. A. Rodriguez, A. M. Roth, G. X. Rousseau, A. Rozen, E. Sayad, L. van Schaik, B. C. Scharenbroch, M. Schirrmann, O. Schmidt, B. Schroder, J. Seeber, M. P. Shashkov, J. Singh, S. M. Smith, M. Steinwandter, J. A. Talavera, D. Trigo, J. Tsukamoto, A. W. de Valenca, S. J. Vanek, I. Virto, A. A. Wackett, M. W. Warren, N. H. Wehr, J. K. Whalen, M. B. Wironen, V. Wolters, I. V. Zenkova, W. Zhang, E. K. Cameron, N. Eisenhauer
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Thu Jul 30, 2020 20:39

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