Browsing by Author "Wang, WQ"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Magnetic structure and magnetocaloric properties of LaMn2Ge2
    (Australian Institute of Nuclear Science and Engineering (AINSE), 2020-11-11) Wang, JL; Cheng, ZX; Wang, WQ; Wang, CW; Hutchison, WD; Campbell, SJ
    The extensive set of ternary intermetallic RMn2X2 compounds (R = rare earth, T = transitional metal, X = Ge or Si) have been investigated extensively in the past few decades due to their interesting range of physical properties [e.g. 1-3]. Recently, significant attention has been paid to the magnetocaloric effect (MCE) of RMn2X2 compounds for their potential application in magnetic refrigeration. Their MCE properties are important as RMn2X2 compounds enable a wide range of structural and magnetic behaviours and related transitions to be controlled via substitution of R, Mn, and X atoms on the 2a, 4d, and 4e sites respectively [e.g. 4-7]. We have carried out a detailed investigation of the LaMn2Ge2 compound using neutron diffraction and magnetic measurements, focusing on the magnetic behaviour of the Mn-sublattice. With decreasing temperature, the magnetic state changes from paramagnetism to incommensurate canted antiferromagnetism AFfs at TN~ 360 K and then gives way to incommensurate canted ferromagnetism Fmi below TC ~ 323 K. No obvious magnetoelastic coupling were detected from refinement of the variable neutron diffraction patterns (5 K - 450K) while detailed analyses of magnetic data indicate that the magnetic phase transition is second order. Under magnetic field changes of 2 T and 8 T, the maximum values of the magnetic entropy change (-DELTASM max) around TC reach 1.65 J/kg K and 4.42 J/kg K, respectively.
  • Thumbnail Image
    Item
    Size‐dependent penetration of nanoparticles in tumor spheroids: a multidimensional and quantitative study of transcellular and paracellular pathways
    (Wiley, 2023-10-11) Chen, W; Wang, WQ; Xie, Z; Centurion, F; Sun, B; Paterson, DJ; Tsao, SCH; Chu, D; Shen, Y; Mao, G; Gu, Z
    Tumor penetration of nanoparticles is crucial in nanomedicine, but the mechanisms of tumor penetration are poorly understood. This work presents a multidimensional, quantitative approach to investigate the tissue penetration behavior of nanoparticles, with focuses on the particle size effect on penetration pathways, in an MDA‐MB‐231 tumor spheroid model using a combination of spectrometry, microscopy, and synchrotron beamline techniques. Quasi‐spherical gold nanoparticles of different sizes are synthesized and incubated with 2D and 3D MDA‐MB‐231 cells and spheroids with or without an energy‐dependent cell uptake inhibitor. The distribution and penetration pathways of nanoparticles in spheroids are visualized and quantified by inductively coupled plasma mass spectrometry, two‐photon microscopy, and synchrotron X‐ray fluorescence microscopy. The results reveal that 15 nm nanoparticles penetrate spheroids mainly through an energy‐independent transcellular pathway, while 60 nm nanoparticles penetrate primarily through an energy‐dependent transcellular pathway. Meanwhile, 22 nm nanoparticles penetrate through both transcellular and paracellular pathways and they demonstrate the greatest penetration ability in comparison to other two sizes. The multidimensional analytical methodology developed through this work offers a generalizable approach to quantitatively study the tissue penetration of nanoparticles, and the results provide important insights into the designs of nanoparticles with high accumulation at a target site. ©2023 The Authors. Small published by Wiley-VCH GmbH. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.