Initial results from the New Horizons exploration of 2014 MU69, a small Kuiper Belt object
We describe initial results from these encounter observations. MU69 is a bilobed contact binary with a flattened shape, discrete geological units, and noticeable albedo heterogeneity. However, there is little surface color or compositional heterogeneity. No evidence for satellites, rings or other dust structures, a gas coma, or solar wind interactions was detected. MU69’s origin appears consistent with pebble cloud collapse followed by a low-velocity merger of its two lobes. (Source: ScienceNOW)
Source: ScienceNOW - May 16, 2019 Category: Science Authors: Stern, S. A., Weaver, H. A., Spencer, J. R., Olkin, C. B., Gladstone, G. R., Grundy, W. M., Moore, J. M., Cruikshank, D. P., Elliott, H. A., McKinnon, W. B., Parker, J. W., Verbiscer, A. J., Young, L. A., Aguilar, D. A., Albers, J. M., Andert, T., Andrews Tags: Online Only, Planetary Science r-articles Source Type: news

Hierarchical reasoning by neural circuits in the frontal cortex
Humans process information hierarchically. In the presence of hierarchies, sources of failures are ambiguous. Humans resolve this ambiguity by assessing their confidence after one or more attempts. To understand the neural basis of this reasoning strategy, we recorded from dorsomedial frontal cortex (DMFC) and anterior cingulate cortex (ACC) of monkeys in a task in which negative outcomes were caused either by misjudging the stimulus or by a covert switch between two stimulus-response contingency rules. We found that both areas harbored a representation of evidence supporting a rule switch. Additional perturbation experime...
Source: ScienceNOW - May 16, 2019 Category: Science Authors: Sarafyazd, M., Jazayeri, M. Tags: Neuroscience, Online Only r-articles Source Type: news

Local protein synthesis is a ubiquitous feature of neuronal pre- and postsynaptic compartments
There is ample evidence for localization of messenger RNAs (mRNAs) and protein synthesis in neuronal dendrites; however, demonstrations of these processes in presynaptic terminals are limited. We used expansion microscopy to resolve pre- and postsynaptic compartments in rodent neurons. Most presynaptic terminals in the hippocampus and forebrain contained mRNA and ribosomes. We sorted fluorescently labeled mouse brain synaptosomes and then sequenced hundreds of mRNA species present within excitatory boutons. After brief metabolic labeling,>30% of all presynaptic terminals exhibited a signal, providing evidence for ongoin...
Source: ScienceNOW - May 16, 2019 Category: Science Authors: Hafner, A.-S., Donlin-Asp, P. G., Leitch, B., Herzog, E., Schuman, E. M. Tags: Cell Biology, Neuroscience, Online Only r-articles Source Type: news

Spatiotemporal light control with active metasurfaces
Optical metasurfaces have provided us with extraordinary ways to control light by spatially structuring materials. The space-time duality in Maxwell’s equations suggests that additional structuring of metasurfaces in the time domain can even further expand their impact on the field of optics. Advances toward this goal critically rely on the development of new materials and nanostructures that exhibit very large and fast changes in their optical properties in response to external stimuli. New physics is also emerging as ultrafast tuning of metasurfaces is becoming possible, including wavelength shifts that emulate the...
Source: ScienceNOW - May 16, 2019 Category: Science Authors: Shaltout, A. M., Shalaev, V. M., Brongersma, M. L. Tags: Physics, Applied, Online Only, Physics review Source Type: news

Uncovering the hidden curriculum
(Source: ScienceNOW)
Source: ScienceNOW - May 16, 2019 Category: Science Authors: Hariharan, J. Tags: Working Life Source Type: news

Technology Feature | Epitranscriptomics: RNA revisited
(Source: ScienceNOW)
Source: ScienceNOW - May 16, 2019 Category: Science Authors: Schubert, C. Tags: opms-sups Source Type: news

New Products
(Source: ScienceNOW)
Source: ScienceNOW - May 16, 2019 Category: Science Tags: products Source Type: news

Mechanism of allosteric modulation of P-glycoprotein by transport substrates and inhibitors
The ATP-binding cassette subfamily B member 1 (ABCB1) multidrug transporter P-glycoprotein plays a central role in clearance of xenobiotics in humans and is implicated in cancer resistance to chemotherapy. We used double electron electron resonance spectroscopy to uncover the basis of stimulation of P-glycoprotein adenosine 5'-triphosphate (ATP) hydrolysis by multiple substrates and illuminate how substrates and inhibitors differentially affect its transport function. Our results reveal that substrate-induced acceleration of ATP hydrolysis correlates with stabilization of a high-energy, post-ATP hydrolysis state characteri...
Source: ScienceNOW - May 16, 2019 Category: Science Authors: Dastvan, R., Mishra, S., Peskova, Y. B., Nakamoto, R. K., Mchaourab, H. S. Tags: Biochemistry reports Source Type: news

Single-cell genomics identifies cell type-specific molecular changes in autism
Despite the clinical and genetic heterogeneity of autism, bulk gene expression studies show that changes in the neocortex of autism patients converge on common genes and pathways. However, direct assessment of specific cell types in the brain affected by autism has not been feasible until recently. We used single-nucleus RNA sequencing of cortical tissue from patients with autism to identify autism-associated transcriptomic changes in specific cell types. We found that synaptic signaling of upper-layer excitatory neurons and the molecular state of microglia are preferentially affected in autism. Moreover, our results show ...
Source: ScienceNOW - May 16, 2019 Category: Science Authors: Velmeshev, D., Schirmer, L., Jung, D., Haeussler, M., Perez, Y., Mayer, S., Bhaduri, A., Goyal, N., Rowitch, D. H., Kriegstein, A. R. Tags: Development, Medicine, Diseases, Neuroscience reports Source Type: news

Hydrodealkenylative C(sp3)-C(sp2) bond fragmentation
Chemical synthesis typically relies on reactions that generate complexity through elaboration of simple starting materials. Less common are deconstructive strategies toward complexity—particularly those involving carbon-carbon bond scission. Here, we introduce one such transformation: the hydrodealkenylative cleavage of C(sp3)–C(sp2) bonds, conducted below room temperature, using ozone, an iron salt, and a hydrogen atom donor. These reactions are performed in nonanhydrous solvents and open to the air; reach completion within 30 minutes; and deliver their products in high yields, even on decagram scales. We have...
Source: ScienceNOW - May 16, 2019 Category: Science Authors: Smaligo, A. J., Swain, M., Quintana, J. C., Tan, M. F., Kim, D. A., Kwon, O. Tags: Chemistry reports Source Type: news

Constrained sialic acid donors enable selective synthesis of {alpha}-glycosides
We present a robust method for the selective α-glycosidation of sialic acid using macrobicyclized sialic acid donors as synthetic equivalents of structurally constrained oxocarbenium ions to impart stereoselectivity. We demonstrate the power of our method by showcasing broad substrate scope and applicability in the preparation of diverse sialic acid–containing architectures. (Source: ScienceNOW)
Source: ScienceNOW - May 16, 2019 Category: Science Authors: Komura, N., Kato, K., Udagawa, T., Asano, S., Tanaka, H.-N., Imamura, A., Ishida, H., Kiso, M., Ando, H. Tags: Chemistry reports Source Type: news

Conformationally supple glucose monomers enable synthesis of the smallest cyclodextrins
In this study, we present methods to chemically synthesize both CD3 and CD4. The main factor in the successful synthesis is the creation of a glucopyranose ring conformationally counterbalanced between equatorial- and axial-rich forms. This suppleness is imparted by a bridge between O-3 and O-6 of glucose, which enables the generation of desirable, albeit deformed, conformers when synthesizing the cyclic trimer and tetramer. (Source: ScienceNOW)
Source: ScienceNOW - May 16, 2019 Category: Science Authors: Ikuta, D., Hirata, Y., Wakamori, S., Shimada, H., Tomabechi, Y., Kawasaki, Y., Ikeuchi, K., Hagimori, T., Matsumoto, S., Yamada, H. Tags: Chemistry reports Source Type: news

Probing and imaging spin interactions with a magnetic single-molecule sensor
Magnetic single atoms and molecules are receiving intensifying research focus because of their potential as the smallest possible memory, spintronic, and qubit elements. Scanning probe microscopes used to study these systems have benefited greatly from new techniques that use molecule-functionalized tips to enhance spatial and spectroscopic resolutions and enable new sensing capabilities. We demonstrate a microscopy technique that uses a magnetic molecule, Ni(cyclopentadienyl)2, adsorbed at the apex of a scanning probe tip, to sense exchange interactions with another molecule adsorbed on a Ag(110) surface in a continuously...
Source: ScienceNOW - May 16, 2019 Category: Science Authors: Czap, G., Wagner, P. J., Xue, F., Gu, L., Li, J., Yao, J., Wu, R., Ho, W. Tags: Chemistry, Physics reports Source Type: news

Electron diffraction determines molecular absolute configuration in a pharmaceutical nanocrystal
We present a complete structure analysis of a pharmaceutical cocrystal of sofosbuvir and l-proline, which is about one order of magnitude less stable. Data collection on multiple positions of a crystal and an advanced-intensity extraction procedure enabled us to solve the structure ab initio. We further show that dynamical diffraction effects are strong enough to permit unambiguous determination of the absolute structure of material composed of light scatterers. (Source: ScienceNOW)
Source: ScienceNOW - May 16, 2019 Category: Science Authors: Brazda, P., Palatinus, L., Babor, M. Tags: Materials Science, Techniques reports Source Type: news

Quantum gas microscopy of Rydberg macrodimers
We report the direct microscopic observation and detailed characterization of such molecules in a gas of ultracold rubidium atoms in an optical lattice. The bond length of about 0.7 micrometers, comparable to the size of small bacteria, matches the diagonal distance of the lattice. By exciting pairs in the initial two-dimensional atom array, we resolved more than 50 vibrational resonances. Using our spatially resolved detection, we observed the macrodimers by correlated atom loss and demonstrated control of the molecular alignment by the choice of the vibrational state. Our results allow for rigorous testing of Rydberg int...
Source: ScienceNOW - May 16, 2019 Category: Science Authors: Hollerith, S., Zeiher, J., Rui, J., Rubio-Abadal, A., Walther, V., Pohl, T., Stamper-Kurn, D. M., Bloch, I., Gross, C. Tags: Physics reports Source Type: news

De novo design of tunable, pH-driven conformational changes
We present a general strategy to design pH-responsive protein conformational changes by precisely preorganizing histidine residues in buried hydrogen-bond networks. We design homotrimers and heterodimers that are stable above pH 6.5 but undergo cooperative, large-scale conformational changes when the pH is lowered and electrostatic and steric repulsion builds up as the network histidine residues become protonated. The transition pH and cooperativity can be controlled through the number of histidine-containing networks and the strength of the surrounding hydrophobic interactions. Upon disassembly, the designed proteins disr...
Source: ScienceNOW - May 16, 2019 Category: Science Authors: Boyken, S. E., Benhaim, M. A., Busch, F., Jia, M., Bick, M. J., Choi, H., Klima, J. C., Chen, Z., Walkey, C., Mileant, A., Sahasrabuddhe, A., Wei, K. Y., Hodge, E. A., Byron, S., Quijano-Rubio, A., Sankaran, B., King, N. P., Lippincott-Schwartz, J., Wysoc Tags: Biochemistry, Molecular Biology r-articles Source Type: news

Identification of a regeneration-organizing cell in the Xenopus tail
Unlike mammals, Xenopus laevis tadpoles have a high regenerative potential. To characterize this regenerative response, we performed single-cell RNA sequencing after tail amputation. By comparing naturally occurring regeneration-competent and -incompetent tadpoles, we identified a previously unrecognized cell type, which we term the regeneration-organizing cell (ROC). ROCs are present in the epidermis during normal tail development and specifically relocalize to the amputation plane of regeneration-competent tadpoles, forming the wound epidermis. Genetic ablation or manual removal of ROCs blocks regeneration, whereas trans...
Source: ScienceNOW - May 16, 2019 Category: Science Authors: Aztekin, C., Hiscock, T. W., Marioni, J. C., Gurdon, J. B., Simons, B. D., Jullien, J. Tags: Cell Biology, Development r-articles Source Type: news

UV light as your guide
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Source: ScienceNOW - May 16, 2019 Category: Science Authors: Lavine, M. S. Tags: twil Source Type: news

Training for cognitive skills
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Source: ScienceNOW - May 16, 2019 Category: Science Authors: Hines, P. J. Tags: twil Source Type: news

Size matters
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Source: ScienceNOW - May 16, 2019 Category: Science Authors: Vignieri, S. Tags: twil Source Type: news

Superresolving atomic densities
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Source: ScienceNOW - May 16, 2019 Category: Science Authors: Stajic, J. Tags: twil Source Type: news

A pharmacological hat trick
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Source: ScienceNOW - May 16, 2019 Category: Science Authors: Kiberstis, P. A. Tags: twil Source Type: news

DNA damage and parental age
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Source: ScienceNOW - May 16, 2019 Category: Science Authors: Zahn, L. M. Tags: twil Source Type: news

Interferometry spots an exoplanet
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Source: ScienceNOW - May 16, 2019 Category: Science Authors: Smith, K. T. Tags: twil Source Type: news

Agents for healthful aging
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Source: ScienceNOW - May 16, 2019 Category: Science Authors: Alderton, G. Tags: twis Source Type: news

Designed to respond
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Source: ScienceNOW - May 16, 2019 Category: Science Authors: Vinson, V. Tags: Biochemistry, Molecular Biology twis Source Type: news

BCAPing inflammasome activation
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Source: ScienceNOW - May 16, 2019 Category: Science Authors: Williams, E. Tags: twis Source Type: news

Machine learning improves hearing aids
(Source: ScienceNOW)
Source: ScienceNOW - May 16, 2019 Category: Science Authors: Clauset, A., Post, K. Tags: twis Source Type: news

Excising an olefin
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Source: ScienceNOW - May 16, 2019 Category: Science Authors: Yeston, J. Tags: Chemistry twis Source Type: news

Sweet spot for making oligosaccharides
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Source: ScienceNOW - May 16, 2019 Category: Science Authors: Funk, M. A. Tags: Chemistry twis Source Type: news

New Horizons flies past MU69
(Source: ScienceNOW)
Source: ScienceNOW - May 16, 2019 Category: Science Authors: Smith, K. T. Tags: Planetary Science twis Source Type: news

Local translation in presynaptic terminals
(Source: ScienceNOW)
Source: ScienceNOW - May 16, 2019 Category: Science Authors: Hurtley, S. M. Tags: Cell Biology, Neuroscience twis Source Type: news

Dynamic metasurfaces
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Source: ScienceNOW - May 16, 2019 Category: Science Authors: Osborne, I. S. Tags: Physics, Applied, Physics twis Source Type: news

Supporting tumor suppression
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Source: ScienceNOW - May 16, 2019 Category: Science Authors: Ray, L. B. Tags: Genetics, Medicine, Diseases twis Source Type: news

Recall responses by human NK cells
(Source: ScienceNOW)
Source: ScienceNOW - May 16, 2019 Category: Science Authors: Williams, I. Tags: twis Source Type: news

The secret life of cediranib
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Source: ScienceNOW - May 16, 2019 Category: Science Authors: Nusinovich, Y. Tags: twis Source Type: news

Bonding's outer limit
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Source: ScienceNOW - May 16, 2019 Category: Science Authors: Yeston, J. Tags: Physics twis Source Type: news

Transport control
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Source: ScienceNOW - May 16, 2019 Category: Science Authors: Vinson, V. Tags: Biochemistry twis Source Type: news

Dynamical refinement spots a difference
(Source: ScienceNOW)
Source: ScienceNOW - May 16, 2019 Category: Science Authors: Funk, M. A. Tags: Materials Science, Techniques twis Source Type: news

Brain cell transcriptomes in autism
(Source: ScienceNOW)
Source: ScienceNOW - May 16, 2019 Category: Science Authors: Hines, P. J. Tags: Development, Medicine, Diseases, Neuroscience twis Source Type: news

The brain circuits of strategic decisions
(Source: ScienceNOW)
Source: ScienceNOW - May 16, 2019 Category: Science Authors: Stern, P. Tags: Neuroscience twis Source Type: news

Visualizing superexchange interactions
(Source: ScienceNOW)
Source: ScienceNOW - May 16, 2019 Category: Science Authors: Szuromi, P. Tags: Chemistry, Physics twis Source Type: news

A tale of tadpole tail regeneration
(Source: ScienceNOW)
Source: ScienceNOW - May 16, 2019 Category: Science Authors: Purnell, B. A. Tags: Cell Biology, Development twis Source Type: news

Improving political deliberation--Response
(Source: ScienceNOW)
Source: ScienceNOW - May 16, 2019 Category: Science Authors: Bächtiger, A., Dryzek, J. Tags: letters Source Type: news

Improving political deliberation
(Source: ScienceNOW)
Source: ScienceNOW - May 16, 2019 Category: Science Authors: Castree, N. Tags: letters Source Type: news

NextGen Voices: Submit Now
(Source: ScienceNOW)
Source: ScienceNOW - May 16, 2019 Category: Science Tags: letters Source Type: news

Fund U.S. veteran toxic exposure database
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Source: ScienceNOW - May 16, 2019 Category: Science Authors: Small, D. S. Tags: letters Source Type: news

Exploitation and extraction
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Source: ScienceNOW - May 16, 2019 Category: Science Authors: Hudson-Edwards, K. Tags: books Source Type: news

An exhibition fit for a king
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Source: ScienceNOW - May 16, 2019 Category: Science Authors: Black, R. Tags: books Source Type: news

Sydney Brenner (1927-2019)
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Source: ScienceNOW - May 16, 2019 Category: Science Authors: Kenyon, C. Tags: perspective Source Type: news