| 1. |
- Åström, E., et al.
(author)
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Precision measurements of linear scattering density using muon tomography
- 2016
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In: Journal of Instrumentation. - : Institute of Physics Publishing. - 1748-0221. ; 11:7
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Journal article (peer-reviewed)abstract
- We demonstrate that muon tomography can be used to precisely measure the properties of various materials. The materials which have been considered have been extracted from an experimental blast furnace, including carbon (coke) and iron oxides, for which measurements of the linear scattering density relative to the mass density have been performed with an absolute precision of 10%. We report the procedures that are used in order to obtain such precision, and a discussion is presented to address the expected performance of the technique when applied to heavier materials. The results we obtain do not depend on the specific type of material considered and therefore they can be extended to any application.
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| 2. |
- Anoushirvani, B., et al.
(author)
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Gamma-ray bursts from primordial quark objects in space
- 1997
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In: Proceedings of the Joint Meeting of the Networks 'The Fundamental Structure of Matter' and 'Tests of the Electroweak Symmetry Breaking', Ouranoupolis, Greece, May 1997.
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Conference paper (peer-reviewed)abstract
- We investigate the possibility that gamma-ray bursts originate in a concentric spherical shell with a given average redshift and find that this is indeed compatible with the data from the third BATSE (3B) catalog. It is also shown that there is enough freedom in the choice of unknown burst properties to allow even for extremely large distances to the majority of bursts. Therefore, we speculate about an early, and very energetic, origin of bursts, and suggest that they come from phase transitions in massive objects of pure quark matter, left over from the Big Bang.
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| 3. |
- Krengel, Ute, 1964, et al.
(author)
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Preliminary X-ray crystallographic analysis of the secreted chorismate mutase from Mycobacterium tuberculosis: A tricky crystallization problem solved
- 2006
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In: Acta Crystallographica Section F: Structural Biology and Crystallization Communications. - 1744-3091. ; 62:5, s. 441-445
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Journal article (peer-reviewed)abstract
- Chorismate mutase catalyzes the conversion of chorismate to prephenate in the biosynthesis of the aromatic amino acids tyrosine and phenylalanine in bacteria, fungi and plants. Here, the crystallization of the unusual secreted chorismate mutase from Mycobacterium tuberculosis (encoded by Rv1885c), a 37.2 kDa dimeric protein belonging to the AroQγ subclass of mutases, is reported. Crystal optimization was non-trivial and is discussed in detail. To obtain crystals of sufficient quality, it was critical to initiate crystallization at higher precipitant concentration and then transfer the drops to lower precipitant concentrations within 5-15 min, in an adaptation of a previously described technique [Saridakis & Chayen (2000), Protein Sci. 9, 755-757]. As a result of the optimization, diffraction improved from 3.5 to 1.3 Å resolution. The crystals belong to space group P21, with unit-cell parameters a = 42.6, b = 72.6, c = 62.0 Å., β = 104.5°. The asymmetric unit contains one biological dimer, with 167 amino acids per protomer. A soak with a transition-state analogue is also described.
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| 4. |
- Ökvist, M., et al.
(author)
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1.6 Å crystal structure of the secreted chorismate mutase from Mycobacterium tuberculosis: Novel fold topology revealed
- 2006
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In: Journal of Molecular Biology. - : Elsevier BV. - 0022-2836 .- 1089-8638. ; 357:5, s. 1483-1499
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Journal article (peer-reviewed)abstract
- The presence of exported chorismate mutases produced by certain organisms such as Mycobacterium tuberculosis has been shown to correlate with their pathogenicity. As such, these proteins comprise a new group of promising selective drug targets. Here, we report the high-resolution crystal structure of the secreted dimeric chorismate mutase from M. tuberculosis (*MtCM; encoded by Rv1885c), which represents the first 3D-structure of a member of this chorismate mutase family, termed the AroQγ subclass. Structures are presented both for the unliganded enzyme and for a complex with a transition state analog. The protomer fold resembles the structurally characterized (dimeric) Escherichia coli chorismate mutase domain, but exhibits a new topology, with helix H4 of*MtCM carrying the catalytic site residue missing in the shortened helix H1. Furthermore, the structure of each*MtCM protomer is significantly more compact and only harbors one active site pocket, which is formed entirely by one polypeptide chain. Apart from the structural model, we present evidence as to how the substrate may enter the active site.
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