527 research outputs found

    Bis(μ-4-hydroxy­benzoato-κ2 O:O′)bis­[triaqua­bis(4-hydroxy­benzoato)-κO;κ2 O,O′-terbium(III)] deca­hydrate

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    The title dinuclear compound, [Tb2(C7H5O3)6(H2O)6]·10H2O, lies on a center of inversion and the two TbIII atoms are bridged by two 4-hydroxy­benzoate anions; each metal atom is further coordinated by one monodentate anion and chelated by the third anion. The eight-coordinate geometry approximates a square anti­prism. Hydrogen bonds of the O—H⋯O type connect the uncoordinated water mol­ecules to the dinuclear species, forming a three-dimensional network

    In situ growth of redox-active iron-centered nanoparticles on graphene sheets for specific capacitance enhancement

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    AbstractA fast and facile approach is proposed to enhance the specific capacitance of N-Methyl-2-pyrrolidone (NMP)-exfoliated graphene. Redox-active nickel ferricyanide (NiFeCN) nanoparticles were grown on the surface of graphene sheets using a simple co-precipitation method. Apart from the synergetic effect of graphene as double layer capacitance and NiFeCN as pseudocapacitance in specific capacitance enhancement, the NiFeCN nanoparticles served as the spacer to prevent the graphene sheets agglomeration. The NiFeCN/graphene exhibited specific capacitance of 113.5Fg−1, which was 2 times higher than the NMP-exfoliated graphene (52Fg−1) and 6times higher than the pure NiFeCN (18Fg−1). The findings suggested the NiFeCN/graphene could be the potential candidate for supercapacitor electrode

    Mechanism of Evolution Shared by Gene and Language

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    We propose a general mechanism for evolution to explain the diversity of gene and language. To quantify their common features and reveal the hidden structures, several statistical properties and patterns are examined based on a new method called the rank-rank analysis. We find that the classical correspondence, "domain plays the role of word in gene language", is not rigorous, and propose to replace domain by protein. In addition, we devise a new evolution unit, syllgram, to include the characteristics of spoken and written language. Based on the correspondence between (protein, domain) and (word, syllgram), we discover that both gene and language shared a common scaling structure and scale-free network. Like the Rosetta stone, this work may help decipher the secret behind non-coding DNA and unknown languages.Comment: 15 pages, 13 figures, 3 tabl

    5,5-Bis(hydroxy­meth­yl)-2-phenyl-1,3-dioxane

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    In the title compound, C12H16O4, the 1,3-dioxane ring adopts a chair conformation; the 2-phenyl substitutent occupies an equatorial position. Adjacent mol­ecules are linked by O—H⋯O hydrogen bonds into a chain

    Methyl 2-(4-chloro-3,5-dinitro­benz­amido)­acetate

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    The title mol­ecule, C10H8ClN3O7, is twisted with the dihedral angle between the amide and benzene ring being 38.75 (11)°. The C—N—C—C torsion angle between the amide and acetyl groups is −150.1 (2)°. Finally, each nitro group is twisted out of the plane of the benzene ring to which it is connected [O—N—C—C torsion angles = 34.0 (3) and −64.5 (3)°]. Linear supra­molecular chains along [010] and mediated by N—H⋯O hydrogen bonds between successive amide groups dominate the crystal packing. The chains are consolidated into the three-dimensional structure by C—H⋯O contacts

    X-ray Astronomy in the Laboratory with a Miniature Compact Object Produced by Laser-Driven Implosion

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    Laboratory spectroscopy of non-thermal equilibrium plasmas photoionized by intense radiation is a key to understanding compact objects, such as black holes, based on astronomical observations. This paper describes an experiment to study photoionizing plasmas in laboratory under well-defined and genuine conditions. Photoionized plasma is here generated using a 0.5-keV Planckian x-ray source created by means of a laser-driven implosion. The measured x-ray spectrum from the photoionized silicon plasma resembles those observed from the binary stars Cygnus X-3 and Vela X-1 with the Chandra x-ray satellite. This demonstrates that an extreme radiation field was produced in the laboratory, however, the theoretical interpretation of the laboratory spectrum significantly contradicts the generally accepted explanations in x-ray astronomy. This model experiment offers a novel test bed for validation and verification of computational codes used in x-ray astronomy.Comment: 5 pages, 4 figures are included. This is the original submitted version of the manuscript to be published in Nature Physic

    Functionally heterogeneous human satellite cells identified by single cell RNA sequencing.

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    Although heterogeneity is recognized within the murine satellite cell pool, a comprehensive understanding of distinct subpopulations and their functional relevance in human satellite cells is lacking. We used a combination of single cell RNA sequencing and flow cytometry to identify, distinguish, and physically separate novel subpopulations of human PAX7+ satellite cells (Hu-MuSCs) from normal muscles. We found that, although relatively homogeneous compared to activated satellite cells and committed progenitors, the Hu-MuSC pool contains clusters of transcriptionally distinct cells with consistency across human individuals. New surface marker combinations were enriched in transcriptional subclusters, including a subpopulation of Hu-MuSCs marked by CXCR4/CD29/CD56/CAV1 (CAV1+). In vitro, CAV1+ Hu-MuSCs are morphologically distinct, and characterized by resistance to activation compared to CAV1- Hu-MuSCs. In vivo, CAV1+ Hu-MuSCs demonstrated increased engraftment after transplantation. Our findings provide a comprehensive transcriptional view of normal Hu-MuSCs and describe new heterogeneity, enabling separation of functionally distinct human satellite cell subpopulations

    Chromosome segregation in Archaea : SegA– and SegB–DNA complex structures provide insights into segrosome assembly

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    Genome segregation is a vital process in all organisms. Chromosome partitioning remains obscure in Archaea, the third domain of life. Here, we investigated the SegAB system from Sulfolobus solfataricus. SegA is a ParA Walker-type ATPase and SegB is a site-specific DNA-binding protein. We determined the structures of both proteins and those of SegA–DNA and SegB–DNA complexes. The SegA structure revealed an atypical, novel non-sandwich dimer that binds DNA either in the presence or in the absence of ATP. The SegB structure disclosed a ribbon–helix–helix motif through which the protein binds DNA site specifically. The association of multiple interacting SegB dimers with the DNA results in a higher order chromatin-like structure. The unstructured SegB N-terminus plays an essential catalytic role in stimulating SegA ATPase activity and an architectural regulatory role in segrosome (SegA–SegB–DNA) formation. Electron microscopy results also provide a compact ring-like segrosome structure related to chromosome organization. These findings contribute a novel mechanistic perspective on archaeal chromosome segregation
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