Peptide-directed crystal growth modification in the formation of ZnO

Biomolecule-mediated synthesis is fascinating in terms of the level of control and the intricate hierarchical structures of the materials that can be produced. In this study we compare the behavior of a phage display identified peptide, EAHVMHKVAPRP (EM-12) with that of a mutant peptide EAHVCHKVAPRP (EC-12), having additional complexation capability, on the formation of ZnO from solution. The synthesis conditions (Zn(CH3COO)2–NH3 hydrothermal method at 50 °C) were chosen to generate rod-shaped ZnO via layered basic zinc salts (LBZs) as intermediates. Both peptides affected the crystal formation process by moderating the amount of Zn2+ ions in solution (EC12 having a greater effect than EM12) but only EC12 was shown to interact with the solid phase(s) formed during the reaction. Depending on the peptide concentration used, EM-12 was shown to delay and/or suppress ZnO formation. In contrast, additions of EC-12, although leading to the retention of higher levels of Zn2+ ions in solution did not similarly delay the transformation of the intermediate phases to ZnO but were found to dramatically modify the morphology of ZnO crystallites with mushroom shaped crystals being formed. From the results of detailed materials characterization and changes in the morphology observed, the interactions between the peptide(s) and solution and solid state species present during the process of ZnO crystal formation in the presence of EM-12 and EC-12 are proposed

Direct measurement of the size of 2003 UB313 from the Hubble Space Telescope

We have used the Hubble Space Telescope to directly measure the angular size of the large Kuiper belt object 2003 UB313. By carefully calibrating the point spread function of a nearby field star, we measure the size of 2003 UB313 to be 34.3$\pm$1.4 milliarcseconds, corresponding to a diameter of 2400$\pm$100 km or a size $\sim5$% larger than Pluto. The V band geometric albedo of 2003 UB313 is $86\pm7$%. The extremely high albedo is consistent with the frosty methane spectrum, the lack of red coloring, and the lack of observed photometric variation on the surface of 2003 UB313. Methane photolysis should quickly darken the surface of 2003 UB313, but continuous evaporation and redeposition of surface ices appears capable of maintaining the extreme alebdo of this body

Hdo And SO2 Thermal Mapping On Venus: Evidence For Strong SO2 Variability

We have been using the TEXES high-resolution imaging spectrometer at the NASA Infrared Telescope Facility to map sulfur dioxide and deuterated water over the disk of Venus. Observations took place on January 10-12, 2012. The diameter of Venus was 13 arcsec, with an illumination factor of 80%. Data were recorded in the 1344-1370 cm(-1) range (around 7.35 mu m) with a spectral resolving power of 80 000 and a spatial resolution of about 1.5 arcsec. In this spectral range, the emission of Venus comes from above the cloud top (z = 60-80 km). Four HDO lines and tens of SO2 lines have been identified in our spectra. Mixing ratios have been estimated from HDO/CO2 and SO2/CO2 line depth ratios, using weak neighboring transitions of comparable depths. The HDO maps, recorded on Jan. 10 and Jan. 12, are globally uniform with no significant variation between the two dates. A slight enhancement of the HDO mixing ratio toward the limb might be interpreted as a possible increase of the D/H ratio with height above the cloud level. The mean H2O mixing ratio is found to be 1.5 +/-0.75 ppm, assuming a D/H ratio of 0.0312 (i.e. 200 times the terrestrial value) over the cloud deck. The SO2 maps, recorded each night from Jan. 10 to Jan. 12, show strong variations over the disk of Venus, by a factor as high as 5 to 10. In addition, the position of the maximum SO2 mixing ratio strongly varies on a timescale of 24 h. The maximum SO2 mixing ratio ranges between 75 +/-25 ppb and 125 +/-50 ppb between Jan. 10 and Jan. 12. The high variability of sulfur dioxide is probably a consequence of its very short photochemical lifetime.NASA NNX-08AE38A, NNX08AW33G S03NSF AST-0607312, AST-0708074Astronom

The Mutual Orbit, Mass, and Density of Transneptunian Binary Gknhmdm (229762 2007 UK126)

We present high spatial resolution images of the binary transneptunian object Gkn'hmdm (229762 2007 UK126) obtained with the Hubble Space Telescope and with the Keck observatory on Mauna Kea to determine the orbit of G' hG' h, the much smaller and redder satellite. G' h orbits in a prograde sense, on a circular or near-circular orbit with a period of 11.3 days and a semimajor axis of 6000 km. Tidal evolution is expected to be slow, so it is likely that the system formed already in a low-eccentricity configuration, and possibly also with the orbit plane of the satellite in or close to the plane of Gkn'hmdm's equator. From the orbital parameters we can compute the system mass to be 1.4 10(exp 20) kg. Combined with estimates of the size of Gkn'hmdm from thermal observations and stellar occultations, we can estimate the bulk density as about 1 g cm(exp 3). This low density is indicative of an ice-rich composition, unless there is substantial internal porosity. We consider the hypothesis that the composition is not unusually ice-rich compared with larger TNOs and comet nuclei, and instead the porosity is high, suggesting that mid-sized objects in the 400 to 1000 km diameter range mark the transition between small, porous objects and larger objects that have collapsed their internal void space as a result of their much higher internal pressures and temperatures

Raman signatures of classical and quantum phases in coupled dots: A theoretical prediction

We study electron molecules in realistic vertically coupled quantum dots in a strong magnetic field. Computing the energy spectrum, pair correlation functions, and dynamical form factor as a function of inter-dot coupling via diagonalization of the many-body Hamiltonian, we identify structural transitions between different phases, some of which do not have a classical counterpart. The calculated Raman cross section shows how such phases can be experimentally singled out.Comment: 9 pages, 2 postscript figures, 1 colour postscript figure, Latex 2e, Europhysics Letters style and epsfig macros. Submitted to Europhysics Letter

Evaluation of Euler Fluxes for Hypersonic Flow Computations

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76462/1/AIAA-33735-324.pd

The Positional Anthropometric and Performance Profile of Elite Gaelic Football Players.

The aim of the current investigation was to evaluate the variation in the anthropometric and performance characteristics of elite Gaelic football players with respect of position. One hundred and forty-eight elite Gaelic footballers underwent anthropometric (height, body mass, sum of seven skinfolds, % adipose tissue) and performance [counter movement jump height (CMJ), CMJ peak power, CMJ relative peak power, squat jump height (SJ), SJ peak power, SJ relative peak power, 5-, 10- and 20 m sprint times and Yo-Yo Intermittent Recovery Test Level 2 (Yo-YoIRT2)] during 'the early in-season' phase. Data were split into five positional groups (full-back, half-back, midfield, half-forward and full-forward). Higher %AT was observed in full forwards when compared to the half backs (p = 0.001), midfielders (p = 0.035) and half forwards (p = 0.021). Full forwards had significantly greater SJ (p = 0.036) and CMJ (p = 0.013) when compared to the midfielders with no other positional differences observed. No significant variation in sprint times was observed across positions. When Yo-YoIRT2 was considered, full forwards and full backs completed significantly lower distances compared to the middle three positional lines of, half backs, midfielders and half forwards (p = 0.00). The current study is the first to provide normative data for anthropometric and performance values of elite Gaelic football players which in turn can be utilised by coaches to generate appropriate training regimes to maximise position specific preparation for competitive match-play

High chronic training loads and exposure to bouts of maximal velocity running reduce injury risk in elite Gaelic football.

OBJECTIVES: To examine the relationship between chronic training loads, number of exposures to maximal velocity, the distance covered at maximal velocity, percentage of maximal velocity in training and match-play and subsequent injury risk in elite Gaelic footballers. DESIGN: Prospective cohort design. METHODS: Thirty-seven elite Gaelic footballers from one elite squad were involved in a one-season study. Training and game loads (session-RPE multiplied by duration in min) were recorded in conjunction with external match and training loads (using global positioning system technology) to measure the distance covered at maximal velocity, relative maximal velocity and the number of player exposures to maximal velocity across weekly periods during the season. Lower limb injuries were also recorded. Training load and GPS data were modelled against injury data using logistic regression. Odds ratios (OR) were calculated based on chronic training load status, relative maximal velocity and number of exposures to maximal velocity with these reported against the lowest reference group for these variables. RESULTS: Players who produced over 95% maximal velocity on at least one occasion within training environments had lower risk of injury compared to the reference group of 85% maximal velocity on at least one occasion (OR: 0.12, p=0.001). Higher chronic training loads (≥4750AU) allowed players to tolerate increased distances (between 90 to 120m) and exposures to maximal velocity (between 10 to 15 exposures), with these exposures having a protective effect compared to lower exposures (OR: 0.22 p=0.026) and distance (OR=0.23, p=0.055). CONCLUSIONS: Players who had higher chronic training loads (≥4750AU) tolerated increased distances and exposures to maximal velocity when compared to players exposed to low chronic training loads (≤4750AU). Under- and over-exposure of players to maximal velocity events (represented by a U-shaped curve) increased the risk of injury