Browsing by Author "Chen, L."

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    Glutamate Dehydrogenase Is Highly Conserved among Clostridium difficile Ribotypes
    Carman, R. J.; Wickham, K. N.; Chen, L.; Lawrence, A. M.; Boone, J. H.; Wilkins, Tracy D.; Kerkering, Thomas M.; Lyerly, D. M. (American Society for Microbiology, 2012-02-01)
    gluD was highly conserved and glutamate dehydrogenase (GDH) was readily expressed in vitro by all 77 Clostridium difficile ribotypes assayed. All ribotypes, including ARL 002, ARL 027, and ARL 106, were reactive in assays that detect C. difficile GDH.
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    On an Equivalence of Divisors on (M)over-bar(0,n) from Gromov-Witten Theory and Conformal Blocks
    Chen, L.; Gibney, A.; Heller, L.; Kalashnikov, E.; Larson, H.; Xu, W. (Springer, 2022-08-16)
    We consider a conjecture that identifies two types of base point free divisors on M ¯ ,n. The first arises from Gromov-Witten theory of a Grassmannian. The second comes from first Chern classes of vector bundles associated with simple Lie algebras in type A. Here we reduce this conjecture on M ¯ ,n to the same statement for n = 4. A reinterpretation leads to a proof of the conjecture on M ¯ ,n for a large class, and we give sufficient conditions for the non-vanishing of these divisors.
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    Spin transition in Gd3N@C-80, detected by low-temperature on-chip SQUID technique
    Chen, L.; Carpenter, Everett E.; Hellberg, Carl S.; Dorn, Harry C.; Shultz, Michael D.; Wernsdorfer, Wolfgang; Chiorescu, Irinel (American Institute of Physics, 2011-04-01)
    We present a magnetic study of the Gd3N@C-80 molecule, consisting of a Gd-trimer via a nitrogen atom, encapsulated in a C-80 cage. This molecular system can be an efficient contrast agent for magnetic resonance imaging (MRI) applications. We used a low-temperature technique able to detect small magnetic signals by placing the sample in the vicinity of an on-chip SQUID. The technique implemented at the National High Magnetic Field Laboratory has the particularity of being able to operate in high magnetic fields of up to 7 T. The Gd3N@C80 shows a paramagnetic behavior and we find a spin transition of the Gd3N structure at 1.2 K. We perform quantum mechanical simulations, which indicate that one of the Gd ions changes from a S-8(7/2) state (L-0, S-7/2) to a F-7(6) state (L-S-3, J-6), likely due to a charge transfer between the C-80 cage and the ion. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3536514]