ResearchSpace@Auckland
University of Auckland Research Repository - ResearchSpace
ResearchSpace is an online archive for the University of Auckland and contains full text theses and other research outputs.
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Recent Submissions
Exploring and Optimising DNA Collection and Extraction from Forensic Samples
(ResearchSpace@Auckland, 2025) Patel, Bhaveena; Harbison, SallyAnn; Lemalu, Anna
DNA analysis is an important aspect of forensic investigations as it helps link individuals to a crime. Forensic scientists face many challenges when attempting to extract DNA from crime scene samples. Samples often contain small amounts of DNA, and analysis can be further challenged by other factors. Examples include exposure to heat, metal surfaces and fingerprint treatments all that may interfere with DNA analyses.
This research focused on the optimisation of the sampling and DNA extraction steps. The objective was to determine the best materials and techniques for sampling and extracting the DNA from forensic samples.
In the first phase swabs (Cultiplast®, SceneSafeTM, Sarstedt, and DNAMICTM) were tested with different wetting agents (Water, Ethanol, BSA, and EDTA) on body fluid samples that had been placed on acetate sheets. It was found that the performance of different sampling materials differed based on the body fluid being sampled. The interpretation of the results was affected by the small sample size and variation. It was found that different combinations of sampling methods were relatively more successful depending on the body fluid type. The use of BSA and DNAMICTM swabs were a promising combination for blood sample collection. This study also showed that Cultiplast® swabs, SceneSafeTM swabs coupled with water and ethanol are fit for purpose, while EDTA and Sarstedt swabs gave relatively less successful results.
The next stage focused on testing different extraction methods (DNA IQTM and the QIAamp DNA Investigator Kit) on different challenging samples: fired cartridge cases, heated metals, and treated fingerprint samples. The DNA Investigator kit performed better than DNA IQ™ for fired cartridge cases and heated metals. DNA IQ™ seemed to be less affected by the presence of fingerprint powder and performed better for this sample type.
Low level DNA results were obtained for the three challenging sample types. DNA profiles suitable for comparison purposes were not obtained and this was not entirely unexpected. Useful insights could still be obtained into combinations of sampling methods and DNA extraction methods to form a starting point for further study.
Design and Manufacture of a Microfluidic Chip Representing Physiological Flows for Placental Organoids
(ResearchSpace@Auckland, 2025) Bhatia, Pranchal; Clark, Alys; James, Jo
Fetal growth restriction (FGR) is a pregnancy complication which occurs due to placental insufficiency. This can be a result of poor formation of the placenta (fetoplacental components), or due to an inadequate supply of nutrient rich maternal blood to the surface of the placenta by the uteroplacental circulation. The placenta is covered by a large multinucleated cell, the syncytiotrophoblast, which is directly in contact with maternal blood delivered by the uteroplacental circulation, and so shear stress exerted by this blood on the syncytiotrophoblast is hypothesised to impact placental growth and development. Thus, there is an interaction between maternal and fetal causes of FGR, leading to complexities in diagnosis and management of the condition.
This thesis presents the design, development, and testing of a microfluidic device, which aims to replicate physiological shear stress on the syncytiotrophoblast, in a unique ‘placentoid’ cell culture which allows for growth of a tree-like structure with similar cell organisation to a real placenta.
Computational fluid dynamics were used to model fluid flow and shear stress in the device. Shear stresses within the physiological range, as reported by Lee et al. (2023), were aimed to be reproduced in the in vitro environment. PDMS bumps were incorporated into the design to allow for trophoblast differentiation into villous tree structures. The thesis concludes by manufacturing and conducting preliminary testing on prototype microfluidic devices. This research aims to increase the knowledge surrounding placental pathophysiology, in conditions like FGR which could later be used to improve diagnostics or targeted therapies for early detection and prevention of FGR.
System responses of reinforced concrete coupled walls systems
(ResearchSpace@Auckland, 2024) Ren-Jie, Tsai; Richard S., Henry; Kenneth J., Elwood
With continuous population growth and limited land space, vertical development in modern buildings has become a trend, leading to construction of mid-to high-rising buildings. In such buildings, one of the efficient lateral force resisting systems is coupled walls system, consisting of wall and coupling beams, which not only provide high lateral stiffness and ductile behavior to control story drift demand but also provide convenience to accommodate requirements from mechanical and electrical systems and spatial planning needs of architects. Compared to RC walls, coupled walls systems possess higher ductility since the coupling beams are designed to dissipate seismic energy.
As New Zealand, Taiwan and several nations are located on the Pacific seismic ring, buildings are inevitably prone to be affected by earthquakes. Post-earthquake reconnaissance reports revealed undesirable performance in wall of some coupled wall structures. Such performance issue was possibly due to the interaction between adjacent structural components, which resulted in the coupling beams being strengthened by restraining their potential axial elongation that led to the undesirable mechanism.
In this study, a database of diagonally RC coupling beam specimens, both with and without axial restraint effect, has been established. The statistical results indicated a significant influence on the probable strength of the beams under axial restraint effect. Furthermore, a numerical model scheme for diagonally RC coupling beams has been validated using the database and incorporated into a coupled wall model scheme which was utilized for parametric study, indicating geometry factors and presence of floor slab rebar have varying influence on axial restraint effect in coupling beams and the axial force demand on wall sections.
To address the potential influence on the axial force demand on the wall sections due to axial restraint effect on the coupling beams in coupled wall systems, this research proposed an estimation of axial restraint force. By combining the proposed axial force with estimation methods for the coupling axial force on wall sections, the results demonstrated the increases in force demands on wall sections as including the axial restraint effect into design procedure, as well as the reinforcement details.
Investigating the role of NAC transcription factors in Actinidia chinensis stigma death
(ResearchSpace@Auckland, 2024) Kelly, Olivia Jane Morrison; Allan, Andrew; Varkonyi-Gasic, Erika
Stigma senescence is a key defining feature of the effective pollination period (EPP); the period in which pollination can produce fruit set and/or seed set. In kiwifruit (Actinidia sp.), pollination is a pressure point for the industry; fruit yield is defined by pollination and seed set, but key pollinators are not attracted to the flowers. The NAC transcription factors KIRA1 (KIR1) and ORESARA1 (ORE1) are regulators of stigma death in Arabidopsis thaliana, and orthologues have been identified in other species. In this project, homologues of KIR1 and ORE1 in gold fleshed kiwifruit (Actinidia chinensis) were identified based on predicted protein similarity. A role in cell death was investigate through analysis of expression patterns throughout A. chinensis, and transient overexpression in Nicotiana benthamiana leaves. A KIR1 homologue, NAC130, produced the strongest cell death phenotype in N. benthamiana leaves. Overexpression of an ORE1 homologue, NAC122, produced a more subtle cell death phenotype. Comparison of the NAC130 and KIR1 promoter regions could indicate a MYB:NAC complex regulates the expression of the two genes. Further functional analysis of NAC130 was performed via the production of gene edited A. chinensis lines (nac130-1), and through transcriptome analysis of N. benthamiana leaves following NAC130 overexpression. Analysis of gene expression in these two systems indicated NAC130 may influence the expression of other NAC transcription factors, including NAC122, as well as the programmed cell death genes CEP1 and PASPA1. The results also suggests a possible role for NAC130 in ethylene and cytokinin signalling pathways. The nac130-1 gene edited line had a significant delay in stigma senescence and altered ovary senescence. Changes in ovary senescence could possibly be attributed to NAC122 and NAC130, both of which are expressed in the senescing ovary. This research has identified key factors that regulate the end of flowering in A. chinensis, which
could be applied to future research or cultivars to optimise pollination in the kiwifruit industry.
Sociodemographic predictors of psychological distress and mental health service use in the Asian New Zealand population
(ResearchSpace@Auckland, 2024) van Tonder, Kayla; D’Souza, Stephanie
This study sought to determine if there was an unmet health need for the Asian New
Zealand population. The purpose of our study was not only to determine if there was an
unmet health need but to also bring awareness to mental health and mental health outcomes
of the Asian New Zealand population as there is very limited research in this space currently.
We examined levels of psychological distress and service use in accordance with
predictor variables such as sociodemographic variables which included sex, deprivation level,
age and an unmet need for broader primary care. Psychological distress was measured using
the Kessler-10 scale where participants recorded either low, moderate to high or high levels
of psychological distress. Service use was measured via pharmaceutical data and hospital
admissions data.
Previous literature had highlighted key differences between Asian and non-Asian
populations both world-wide and within the New Zealand context. Across most studies, Asian
individuals had reported greater levels of psychological distress and lower levels of mental
health service use. While our findings were consistent with the latter, we saw the opposite
trend in psychological distress levels between the Asian and non-Asian New Zealand groups.
This difference however, may be due to a confounding variable in the non-Asian group as this
ethnic group comprised of all other ethnicities within New Zealand (that did not identify with
the Asian ethnicity).
Future research may aim to address any confounding variables as well as disaggregate
Asian ethnicities beyond a level one or two description.