Browsing by Author "Lin, B"

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    Derivatives of imidazotriazine and pyrrolotriazine C-nucleosides as potential new anti-HCV agents
    (Elsevier B.V., 2014-11-01) Draffan, AG; Frey, B; Fraser, BH; Pool, B; Gannon, C; Tyndall, EM; Cianci, J; Harding, M; Lilly, M; Hufton, R; Halim, R; Jahangiri, S; Bond, S; Jeynes, TP; Nguyen, VTT; Wirth, V; Luttick, A; Tilmanis, D; Pryor, M; Porter, K; Morton, CJ; Lin, B; Duan, J; Bethell, RC; Kukojl, G; Simoneau, B; Tucker, SP
    Previous investigations identified 2′-C-Me-branched ribo-C-nucleoside adenosine analogues, 1, which contains a pyrrolo[2,1-f][1,2,4]triazin-4-amine heterocyclic base, and 2, which contains an imidazo[2,1-f][1,2,4]triazin-4-amine heterocyclic base as two compounds with promising anti-HCV in vitro activity. This Letter describes the synthesis and evaluation of a series of novel analogues of these compounds substituted at the 2-, 7-, and 8-positions of the heterocyclic bases. A number of active new HCV inhibitors were identified but most compounds also demonstrated unacceptable cytotoxicity. However, the 7-fluoro analogue of 1 displayed good potency with a promising cytotherapeutic margin. © 2014 Elsevier Ltd.
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    Structural characterization of a model gram-negative bacterial surface using lipopolysaccharides from rough strains of escherichia coli
    (American Chemical Society, 2013-06-01) Le Brun, AP; Clifton, LA; Halbert, CE; Lin, B; Meron, M; Holden, PJ; Lakey, JH; Holt, SA
    Lipopolysaccharides (LPS) make up approximately 75% of the Gram-negative bacterial outer membrane (OM) surface, but because of the complexity of the molecule, there are very few model OMs that include LPS. The LPS molecule consists of lipid A, which anchors the LPS within the OM, a core polysaccharide region, and a variable O-antigen polysaccharide chain. In this work we used RcLPS (consisting of lipid A plus the first seven sugars of the core polysaccharide) from a rough strain of Escherichia coli to form stable monolayers of LPS at the air?liquid interface. The vertical structure RcLPS monolayers were characterized using neutron and X-ray reflectometry, while the lateral structure was investigated using grazing incidence X-ray diffraction and Brewster angle microscopy. It was found that RcLPS monolayers at surface pressures of 20 mN m(-1) and above are resolved as hydrocarbon tails, an inner headgroup, and an outer headgroup of polysaccharide with increasing solvation from tails to outer headgroups. The lateral organization of the hydrocarbon lipid chains displays an oblique hexagonal unit cell at all surface pressures, with only the chain tilt angle changing with surface pressure. This is in contrast to lipid A, which displays hexagonal or, above 20 mN m(-1), distorted hexagonal packing. This work provides the first complete structural analysis of a realistic E. coli OM surface model. © 2013, American Chemical Society.
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    Study of structure morphology and layer thickness of Ti3C2 MXene with small-angle neutron scattering (SANS)
    (Elsevier B. V., 2021-07-05) Yuen, ACY; Chen, TBY; Lin, B; Yang, W; Kabir, II; Cordeiro, IMDC; Whitten, AE; Mata, JP; Yu, B; Lu, HD; Yeoh, GH
    MXene is a class of 2D materials exfoliated from ternary carbide and nitride ceramics. During synthesis, etching and delamination conditions affect the quality, overall crystallinity, defects and surface functionalization of MXene flakes. In this article, the morphological structure of MXene (Ti3C2) nanosheets under temperature between 20 °C and 60 °C were investigated with the application of Small-Angle Neutron Scattering (SANS) combined with several complementary techniques, such as Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) and X-ray Photoelectron Spectroscopy (XPS). The SANS analysis enabled structural information to be obtained about the Ti3C2 nanosheets, which consists of layers of transition metal carbides in a multilayer lamella morphology. The results showed that a single Ti3C2 layer is approximately 11.4 – 11.8 Å (1.14 – 1.18 nm) in thickness with a 20.3 – 21.5 Å (2.03 – 2.15 nm) interstacking layer gaps. This results in a total thickness of approximately 32 Å (3.2 nm), which was consistent with the model-dependent lamella model analysis. Furthermore, the thickness of the Ti3C2 layer increased by approximately ~2 Å (0.2 nm) when the temperature increased from 20 - 40 to 50 - 60 °C. © 2021 The Author(s). Published by Elsevier B.V.