1,417 research outputs found

    Getting to the Point? Rethinking Arrows on Maps

    Get PDF
    Introduction. Maps help to form public opinion and build public morale. When the war is over, they will contribute to shaping the thought and action of those responsible for the reconstruction of a shattered world. Hence it is important in these times that the nature of the information they set forth should be well understood (Wright, 1942: 527)

    Total Synthesis of the Bovine Pancreatic Trypsin Inhibitor (BPTI) and the Protein Diastereomer [Gly37D-Ala]BPTI using Boc Chemistry Solid Phase Peptide Synthesis

    Get PDF
    Bovine pancreatic trypsin inhibitor (BPTI) is a well‐studied model for investigation of protein folding and stability. Here, we report the synthesis and characterization of wild‐type BPTI and a diastereomeric protein analogue [Gly37D‐Ala]BPTI. Each 58‐residue polypeptide chain was made by native chemical ligation of two peptide segments, BPTI[1‐29]‐αthioester and the appropriate version of the Cys30‐58 BPTI peptide segment. Boc chemistry in situ neutralization solid phase synthesis was used to prepare the peptide segment reactants. The resulting full‐length polypeptide chains were folded in a cysteine/cystine redox buffer to give synthetic protein molecules containing three disulfide bonds. The diastereomeric analogue [Gly37D‐Ala]BPTI folded as efficiently as the native protein. Synthetic proteins were characterized by analytical LCMS and by natural‐abundance 1H‐15N HSQC NMR fingerprinting. These results illustrate the power of Boc chemistry peptide synthesis and its utility for the total chemical synthesis of protein molecules

    Exile Vol. XXXVI No. 1

    Get PDF
    untitled by Nichola Gracille (Cover) Words by Kent Lambert 1 Talk by Richard Latimer 2 Storm Passing by Ben Kell 3 untitled by Ed Stanley 4 I Again Awake by Sharnon Salser 5-6 Demigods and Demons by Kent Lambert 7 untitled by Tim Loving 8 Apology by Kelly Bondurant 9-10 Guest Speaker by Ann Mierson 11 untitled by Nicalas Gracilla 12 Watching for Minnows by Kent Lambert 13 Thunderbird by Kelly Bondurant 14-16 Glendalough (St. Kevin) by Ben Kell 17-18 Untitled by Craig Bagno 19 Flying Machines In Pieces On The Ground by Kelly Bondurant 20 Tuesday, December 13, 1988 Bill & Walt\u27s Toy Shoppe by Alexander Speyer 21 Weathered Wood by Kelly Bondurant 22 Above Grey Water by Susanna Duff 23-25 untitled by Ed Stanley 26 Contributor\u27s Notes 27 Editorial decision is shared equally among the Editorial Board -

    The structure of the nuclear stellar cluster of the Milky Way

    Get PDF
    We present high-resolution seeing limited and AO NIR imaging observations of the stellar cluster within about one parsec of Sgr A*, the massive black hole at the centre of the Milky Way. Stellar number counts and the diffuse background light density were extracted from these observations in order to examine the structure of the nuclear stellar cluster.Our findings are as follows: (a) A broken-power law provides an excellent fit to the overall structure of the GC nuclear cluster. The power-law slope of the cusp is Γ=0.19±0.05\Gamma=0.19\pm0.05, the break radius is Rbreak=6.0â€Čâ€Č±1.0â€Čâ€ČR_{\rm break} = 6.0'' \pm 1.0'' or 0.22±0.040.22\pm0.04 pc, and the cluster density decreases with a power-law index of Γ=0.75±0.1\Gamma=0.75\pm0.1 outside of RbreakR_{\rm break}. (b) Using the best velocity dispersion measurements from the literature, we derive higher mass estimates for the central parsec than assumed until now. The inferred density of the cluster at the break radius is 2.8±1.3×106M⊙pc−32.8\pm1.3\times 10^{6} {\rm M_{\odot} pc^{-3}}. This high density agrees well with the small extent and flat slope of the cusp. Possibly, the mass of the stars makes up only about 50% of the total cluster mass. (c) Possible indications of mass segregation in the cusp are found (d) The cluster appears not entirely homogeneous. Several density clumps are detected that are concentrated at projected distances of R=3â€Čâ€ČR=3'' and R=7â€Čâ€ČR=7'' from Sgr A*.(e) There appears to exist an under-density of horizontal branch/red clump stars near R=5â€Čâ€ČR=5'', or an over-density of stars of similar brightness at R=3â€Čâ€ČR=3'' and R=7â€Čâ€ČR=7''. (f) The extinction map in combination with cometary-like features in an L'-band image may provide support for the assumption of an outflow from Sgr A*.Comment: accepted for publication by A&A; please contact first author for higher quality figure

    High-Rate Intercalation without Nanostructuring in Metastable Nb2O5 Bronze Phases.

    Get PDF
    Nanostructuring and nanosizing have been widely employed to increase the rate capability in a variety of energy storage materials. While nanoprocessing is required for many materials, we show here that both the capacity and rate performance of low-temperature bronze-phase TT- and T-polymorphs of Nb2O5 are inherent properties of the bulk crystal structure. Their unique "room-and-pillar" NbO6/NbO7 framework structure provides a stable host for lithium intercalation; bond valence sum mapping exposes the degenerate diffusion pathways in the sites (rooms) surrounding the oxygen pillars of this complex structure. Electrochemical analysis of thick films of micrometer-sized, insulating niobia particles indicates that the capacity of the T-phase, measured over a fixed potential window, is limited only by the Ohmic drop up to at least 60C (12.1 A·g(-1)), while the higher temperature (Wadsley-Roth, crystallographic shear structure) H-phase shows high intercalation capacity (>200 mA·h·g(-1)) but only at moderate rates. High-resolution (6/7)Li solid-state nuclear magnetic resonance (NMR) spectroscopy of T-Nb2O5 revealed two distinct spin reservoirs, a small initial rigid population and a majority-component mobile distribution of lithium. Variable-temperature NMR showed lithium dynamics for the majority lithium characterized by very low activation energies of 58(2)-98(1) meV. The fast rate, high density, good gravimetric capacity, excellent capacity retention, and safety features of bulk, insulating Nb2O5 synthesized in a single step at relatively low temperatures suggest that this material not only is structurally and electronically exceptional but merits consideration for a range of further applications. In addition, the realization of high rate performance without nanostructuring in a complex insulating oxide expands the field for battery material exploration beyond conventional strategies and structural motifs.K.J.G. gratefully acknowledges funding from The Winston Churchill Foundation of the United States and the Herchel Smith Scholarship. A.C.F. and J.M.G thank the EPSRC, via the Supergen consortium, for funding. A.C.F. is also thankful to the Sims Scholarship for support.This is the final version of the article. It first appeared in the American Chemical Society via http://dx.doi.org/10.1021/jacs.6b0434

    Morphologies of AGN host galaxies using HST/ACS in the CDFS-GOODS field

    Full text link
    Using HST/ACS images in four bands F435W, F606W, F775W and F850LP, we identify optical counterparts to the X-ray sources in the Chandra Deep Field South in the GOODS South field. A detailed study has been made of these sources to study their morphological types. We use methods like decomposition of galaxy luminosity profiles, color maps and visual inspection of 192 galaxies which are identified as possible optical counterparts of Chandra X-ray sources in the CDFS-GOODS field. We find that most moderate luminosity AGN hosts are bulge dominated in the redshift range (z \approx 0.4-1.3), but not merging/interacting galaxies. This implies probable fueling of the moderate luminosity AGN by mechanisms other than those merger driven.Comment: pdflatex, accepted in ApSS. revisions in tex
    • 

    corecore