Browsing by Author "Chen, F"

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    Dopamine transporter and D2 receptor binding densities in mice prone or resistant to chronic high fat diet-induced obesity
    (Elsevier Science BV, 2006-12-15) Huang, XF; Zavitsanou, K; Huang, X; Yu, YH; Wang, HQ; Chen, F; Lawrence, AJ; Deng, C
    This study examined the density of dopamine transporter (DAT) and D2 receptors in the brains of chronic high-fat diet-induced obese (cDIO), obese-resistant (cDR) and low-fat-fed (LF) control mice. Significantly decreased DAT densities were observed in cDR mice compared to cDIO and LF mice, primarily in the nucleus accumbens, striatal and hypothalamic regions. D2 receptor density was significantly lower in the rostral part of caudate putamen in cDIO mice compared to cDR and LF mice. © 2006, Elsevier Ltd.
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    Drug-induced morphology transition of self-assembled glycopolymers: insight into the drug-polymer interaction
    (Australian Institute of Nuclear Science and Engineering (AINSE), 2018-11-18) Cao, C; Zhao, JC; Chen, F; Lu, MG; Khine, YY; Macmillanc, A; Garvey, CJ; Stenzel. M
    It is often assumed that a hydrophobic drug will be entrapped in the hydrophobic environment of a micelle. Little attention is usually drawn to the actual location of the drug and the effect of the drug on properties. In this publication, we show how the chosen drug curcumin is not only unexpectedly located in the shell of the micelle, but that the accumulation in the hydrophilic block can lead to changes in morphology during self-assembly. A block copolymer poly(1-O-methacryloyl -β-D-fructopyranose)-b-poly(methyl methacrylate), Poly(1-O-MAFru)36-b-PMMA192, was loaded with different amounts of curcumin. The resulting self-assembled nanoparticles were analyzed using TEM, SAXS, and SANS. Initial microscopy evidence revealed that the presence of the drug induces morphology changes from cylindrical micelles (no drug) to polymersomes, which decreased in size with increasing amount of drug (Figure 1). SAXS and SANS analysis, supported by fluorescence studies, revealed that the drug is interacting with the glycopolymer block. The drug did not only influence the shape of the drug carrier, but also the level of cof the shell. Increasing the amount of drug dehydrated the nanoparticle shell, which coincided with a lower nanoparticle uptake by MCF-7 breast cancer cells and non-cancerous Raw-264.7 cells. As a result, we showed that the drug can influence the behaviour of the fluorescence in terms of shape and shell hydration, which could influence the performance in a biological setting (Figure 1). Although the depicted scenario may not apply to every drug carrier, it is worth evaluation if the drug will interfere in unexpected ways, for example, when the drug locates on the surface and affects the internal structure of the nanocarrier. © The Authors.
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    Effect of silicon on the distribution and speciation of uranium in sunflower (Helianthus annuus)
    (Elsevier, 2024-10) Wang, LL; Laing, Y; Liu, S; Chen, F; Wang, JG; Chen, YL; Paterson, DJ; Kopittke, PM; Wang, YH; Liu, C; Ye, Y
    Sunflower (Helianthus annuus) can potentially be used for uranium (U) phytoremediation. However, the factors influencing the absorption of U and its subsequent distribution within plant tissues remain unclear, including the effect of silicon (Si) which is known to increase metal tolerance. Here, using hydroponics, the effect of Si on the distribution and speciation of U in sunflower was examined using synchrotron-based X–ray fluorescence and fluorescence-X-ray absorption near-edge spectroscopy. It was found that ∼88 % of U accumulates within the root regardless of treatments. Without the addition of Si, most of the U appeared to bind to epidermis within the roots, whereas in the leaves, U primarily accumulated in the veins. The addition of Si alleviated U phytotoxicity and decreased U concentration in sunflower by an average of 60 %. In the roots, Si enhanced U distribution in cell walls and impeded its entry into cells, likely due to increased callose deposition. In the leaves, Si induced the sequestration of U in trichomes. However, Si did not alter U speciation and U remained in the hexavalent form. These results provide information on U accumulation and distribution within sunflower, and suggest that Si could enhance plant growth under high U stress. © 2024 Elsevier B.V.