UC Research Repository

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The UC Research Repository collects, stores and makes available original research from postgraduate students, researchers and academics based at the University of Canterbury.

 

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ItemOpen Access
Deterministic X-ray Bragg coherent diffraction imaging as a seed for subsequent iterative reconstruction
(IOP Publishing, 2018) Pavlov, Konstantin; Morgan KS; Punegov VI; Paganin DM
Coherent diffractive imaging (CDI), using both x-rays and electrons, has made extremely rapid progress over the past two decades. The associated reconstruction algorithms are typically iterative, and seeded with a crude first estimate. A deterministic method for Bragg Coherent Diffraction Imaging (Pavlov et al 2017 Sci. Rep. 7 1132) is used as a more refined starting point for a shrink-wrap iterative reconstruction procedure. The appropriate comparison with the autocorrelation function as a starting point is performed. Real-space and Fourier-space error metrics are used to analyse the convergence of the reconstruction procedure for noisy and noise-free simulated data. Our results suggest that the use of deterministic-CDI reconstructions, as a seed for subsequent iterative-CDI refinement, may boost the speed and degree of convergence compared to the cruder seeds that are currently commonly used. We also highlight the utility of monitoring multiple error metrics in the context of iterative refinement.
ItemOpen Access
Effects of Resveratrol on In Vivo Ovarian Cancer Cells Implanted on the Chorioallantoic Membrane (CAM) of a Chicken Embryo Model
(MDPI AG, 2024) Chitcholtan K; Singh M; Tino A; Garrill, Ashley; Sykes P
Ovarian cancer poses a significant threat to patients in its advanced stages, often with limited treatment options available. In such cases, palliative management becomes the primary approach to maintaining a reasonable quality of life. Therefore, the administration of any medication that can benefit patients without a curative option holds potential. Resveratrol, a natural compound known for its in vitro anticancer activities, has generated contrasting results in vivo and human studies. In this study, we aimed to assess the anticancer effects of resveratrol on ovarian cancer cells grown on the chorioallantoic membrane (CAM) of chicken embryos. Two ovarian cancer cell lines, OVCAR-8 and SKOV-3, were cultured in collagen scaffolds for four days before being implanted on the CAM of chicken embryos on day 7. Different doses of resveratrol were applied to the CAM every two days for six days. Subsequently, CAM tissues were excised, fixed, and subjected to histological analysis. Some CAM tumours were extracted to analyse proteins through Western blotting. Our findings indicate that specific doses of resveratrol significantly reduce angiogenic activities, pNF-κB levels, and SLUG protein levels by using immunohistochemistry. These results suggest that resveratrol may have the potential to impact the behaviour of ovarian cancer CAM tumours, thereby warranting further consideration as a complementary treatment option for women with incurable ovarian cancer.
ItemOpen Access
Task-shifting or problem-shifting? How lay counselling is redefining mental healthcare
(Public Library of Science (PLoS), 2024) Chase L; Shrestha P; Datta G; Forsythe N; Jain S; Maharjan SM; Mathias, Kaaren; Miguel-Lorenzo X; Ranganathan S; Shrestha S; Sidgel K; Subba P; Gautam K; Gurung D; Ntow MC; Montague-Cardoso K
ItemOpen Access
Editorial
(2024) Sawyer, Adrian; Tan Lin Mei
ItemOpen Access
Monotonic Drained and Undrained Shear Behaviors of Compacted Slightly Weathered Tephras from New Zealand
(MDPI AG, 2024) Sood S; Chiaro, Gabriele; Wilson, Thomas; Stringer M
This paper reports and discusses the results of a series of monotonic compression drained and undrained triaxial tests performed on three compacted, slightly weathered silty sand tephras. In total, 18 drained and 18 undrained tests were performed on compacted specimens (at Dc ≈ 90 and 100%) isotropically consolidated at confining pressures of 50–200 kPa. It was observed that particle size distribution, weathering state, and mineralogy of the tephra deposits had significant effects on the stress–strain responses, friction angles, stress–dilatancy relations, and critical state characteristics. For instance, the coarser tephra (namely white–grey Kaharoa, that was less affected by weathering processes) showed a primarily dilative response. The effects of chemical composition, namely weathering degree and mineralogy, on geotechnical properties such as friction angle were investigated with an attempt to interlink the two characteristics for heterogeneous tephras. The measured friction angles (ϕ = 32.7°–42.8°), combined with the results of weathering degrees and mineralogical investigations, indicated that silty sand tephras, if properly compacted, are suitable fills for use in typical geotechnical applications.