424,857 research outputs found

    A photoactivatable small molecule probe for the in vivo capture of polyketide intermediates

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    A photolabile carba(dethia) malonyl N‐acetylcysteamine derivative was devised and prepared for the trapping of biosynthetic polyketide intermediates following light activation. From the lasalocid A polyketide assembly in a mutant strain of the soil bacterium S. lasaliensis, a previously undetected cyclised intermediate was identified and characterised, providing a new outlook on the timing of substrate processing

    Coupling device for moving vehicles

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    A mechanical system is disclosed to capture and/or deploy a device or vehicle having relative motion with respect to another vehicle. The mechanism includes an onboard controlled collapsible iris assembly located at the end of a controlled manipulator system carried by one moving vehicle. The iris assembly by means of the manipulator system encircles a probe located on the other moving vehicle whereupon the iris assembly is activated and one or more iris elements close around the probe, thus capturing, and axially aligning the other vehicle with the iris assembly. Additionally, a rotator assembly is included for spinning the iris assembly in a manner adapted to engage the probe of a spinning vehicle. Deployment of the other vehicle is accomplished by reversing the capture procedure

    Tomograms of Spinning Black Holes

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    The classical internal structure of spinning black holes is vastly different from that of static black holes. We consider spinning BTZ black holes, and probe their interior from the gauge theory. Utilizing the simplicity of the geometry and reverse engineering from the geodesics, we propose a thermal correlator construction which can be interpreted as arising from two entangled CFTs. By analytic continuation of these correlators, we can probe the Cauchy horizon. Correlators that capture the Cauchy horizon in our work have a structure closely related to those that capture the singularity in a non-rotating BTZ. As expected, the regions beyond the Cauchy horizon are not probed in this picture, protecting cosmic censorship.Comment: 41 pages, 7 figure

    Preliminary capture trajectory design for Europa tomography probe

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    The objective of this work is the preliminary design of a low-DV transfer from an initial elliptical orbit around Jupiter into a final circular orbit around the moon Europa. This type of trajectory represents an excellent opportunity for a low-cost mission to Europa, accomplished through a small orbiter, as in the proposed Europa Tomography Probe mission, a European contribution to NASA’s Europa Multiple-Flyby Mission (or Europa Clipper). The mission strategy is based on the v-infinity leveraging concept, and the use of resonant orbits to exploit multiple gravity-assist from the moon. Possible sequences of resonant orbits are selected with the help of the Tisserand graph. Suitable trajectories are provided by an optimization code based on the parallel running of several differential evolution algorithms. Different solutions are finally compared in terms of propellant consumption and flight time

    Polarized Proton Pionic Capture in Deuterium as a Probe of 3N Dynamics

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    The proton analyzing power Ay in pion production reaction pd --> pi0 3He has been calculated including one- and two-body meson production mechanisms with a proper treatment of the three-nucleon dynamics and an accurate solution of the 3N bound-state problem for phenomenological two-nucleon potentials. In the region around the Delta resonance, the structure of the analyzing power can be understood once interference effects among amplitudes describing intermediate Delta N formation in different orbital states are considered along with the additional interference with the S-wave pion production amplitudes. Then, the inclusion of three-nucleon dynamics in the initial state produces the structure of the analyzing power that has been observed experimentally.Comment: 9 pages, 5 figure

    Development of a genosensor for peanut allergen ARA h 2 detection and its optimization by surface response methodology

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    A new selective electrochemical genosensor has been developed for the detection of an 86-mer DNA peanut sequence encoding part of the allergen Arah2(conglutin-homologprotein).The method is base on a sandwich format,which presents two advantages:it permits shortening the capture probe and avoids labeling of the target.Screen-printed gold electrodes have been used as platformfor the immobilization of oligo nucleotides by the well-knownS–Aubond.Mixedself-assembled monolayers (SAM), including thiol-modified capture probe and mercaptohexanol,were prepared to a chieve an organized, homogeneous and not too compact SAM in which unspecific adsorption of the capture probe would be prevented..
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