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The disruption to trains caused by rail maintenance commonly happens in operation. The stress state drives this issue as it causes damage to track. The longitudinal stress is induced by change in the temperature during extreme weather, especially in the widely used Continue Welded Rails (CWR) since there is no space for rail expansion. Existing stress measurement solutions to deal with this problem are either time/cost-consuming or destructive. Therefore, this project is aiming to develop a new non-destructive stress measurement device based on ultrasound, for rails, which is urgently needed and beneficial to the transportation industry. Previous researchers have shown the possibility of stress monitoring by using ultrasound and compared to other theories, this might be the best choice at the moment. The work in the PhD consists of five stages of testing. A pilot lab test for validating the ultrasonic stress measurement principle in small specimens, while, determining the most suitable transducer frequency and arrangement. After that, rail material study paralleled with validation testing of a removable transducer with rail specimens was conducted. Once the removable transducer-based system was built, laboratory testing with rail sections was performed to justify the versatility of the measurement system by testing it on different rails. In the real working condition, there are many random variables that must be assessed before a new system is turned into a commercial version, thus, field testing was critical in this work. Based on the performance from the field testing, an iteration can be delivered for improving accuracy and durability of the system. By using this rail stress monitoring system, the rail stress condition can be accessed without cutting the rail and closing the line from service, therefore, significant savings in operating and manpower costs can be achieved in the rail industry.

Motivation has been regarded as one key factor for successfully learning a second language (L2). This mixed-method study examined the effects of an Ideal-L2-Self-based intervention on second-year college English majors’ L2 selves (the Ideal L2 Self and the Ought-to L2 Self), learners’ perception of the L2 Learning Experience and the intended learning and motivation efforts needed in L2 learning in China. The 4-week intervention consisted of 8 whole-class sessions and 2 one-on-one counseling meetings with the instructor. The quasi-experiment included 50 second-year English majors with equal numbers serving in the treatment and control groups. Pretest and posttest data were collected using a L2 Motivation Questionnaire. One-way ANCOVAs were used to address the quantitative research questions. The posttest served as the dependent variable and the pretest served as the covariate, along with group (treatment versus control) as the fixed factor. Content analysis was employed using documents written by all students in the treatment group during the intervention and transcripts of individual interviews conducted with five of these students. The results of the study showed that the Ideal L2 Self of the students who attended the intervention was significantly strengthened after the intervention by demonstrating extended dimensions, more vivid vision and strengthened confidence in forming the vision. The students’ Ought-to L2 Self was weakened with moderate effect size, by better vision of language learning and more focus on learning aims. The students’ L2 Learning Experience was greatly improved by stronger vision of English use. The students’ Intended L2 Learning Efforts were significantly increased by forming clearer learning aims, turning passive learning to active learning, and having detailed action plans and reflections. The strengthened Ideal L2 Self was effective to weaken the Ought-to L2 Self, and thus decrease the pressure from others’ opinions on students’ language learning. The strong Ideal L2 Self helped to decrease the negative impact of L2 Learning Experience and improve the students’ perception of existing learning experience. Finally, it helped students be more willing to learn English and put more efforts in the learning process. Thus, this study suggests that the Ideal-L2-Self intervention can be an effective way of promoting the L2 motivation of English majors whose characteristics and context are similar to those participating in this study. In language teaching, it is important for teachers to strengthen learners’ Ideal L2 Self by improving their confidence and encourage students to focus on their own learning process by providing them with various supportive motivational strategies, such as detailed analysis of learning aims, obstacles and a realistic action plan with meaningful reflections.

Alzheimer’s disease (AD) and Lewy body diseases (LBD) are the two most common age-related neurodegenerative diseases characterized by neuronal loss and abnormal protein aggregations (Aβ and phosphorylated tau in AD, and α-synuclein in LBD). Ageing is the single most common risk factor for both AD and LBD, and neuronal senescence may therefore be a potential underlying factor for these diseases. Whether neuronal senescence increases with age or age-related neurodegenerative diseases, and whether it is related to the cell loss and protein deposition observed remains to be determined. Following institutional approvals, formalin fixed brain tissue samples were acquired from the New South Wales Brain Banks for 35 elderly controls, 10 AD, 17 LBD and 6 multiple system atrophy (MSA) cases. Depending on the study, dissociated nuclei from the hippocampal CA1 region, the anterior cingulate cortex, the substantia nigra and/or the pontine base were assessed using flow cytometry for cell number (validated using optical methods) and average DNA content, and immunohistochemistry for the severity of protein deposition and the expression of the cell senescence marker, nuclear P16INK4a. Initial assessment of aneuploidy revealed no significant increase during normal brain ageing, no increase in the α-synucleinopathy MSA, but significantly more hyperploid neurons in AD and LBD. The increase in hyperploid neurons occurred prior to significant neuronal loss in cortical regions, relating most to AD type protein depositions, but also independently to substantia nigra cell loss. These relationships were confirmed by assessing the nuclear expression of cell cycle repressor P16INK4a which was decreased in both tangle-bearing neurons and tangle-free neurons, and negatively associated with the increase in aneuploidy. Importantly, the reduction in nuclear P16INK4a occurred in controls with high tau burden, showing that the loss of nuclear P16INK4a occurs prior to the induction of aneuploidy. Overall the data suggest that reduced nuclear expression of P16INK4a predisposes neurons to aneuploidy and neurodegeneration. Further identification of the mechanisms involved are required, and the early events precipitating a reduction in nuclear P16INK4a need to be determined.

Plant hormones are small molecules that regulate various aspects of plant growth and development. Plant hormones are often chemically modified in the cell to affect their storage, degradation, or transport. We had previously discovered that two genes belonging to the Arabidopsis thaliana SABATH methyltransferase (MT) family encode enzymes that catalyze the methylation of the plant hormones salicylic acid (SA) and jasmonic acid. The Arabidopsis genome contains 22 other genes belonging to the SABATH family, whose catalytic functions at the time were unknown. Using a biochemical genomic approach, I, together with co-workers, have identified a SABATH MT that methylates the plant hormone indole-3-acetic acid (IAA), and two other SABATH MTs that methylate another class of plant hormones, the gibberellins (GAs). Biochemical characterizations of these MTs have shown that they are specific for the respective hormone substrate. In addition, mutant plants with ectopic expression of IAA or GA methyltransferases show a disruption in hormonal homeostasis. The discoveries that IAA and GAs could be methylated are novel. However, the in vivo functions of methylated plant hormones such as SA methylester (MeSA) and IAA methylester (MeIAA) had not yet been determined. I have therefore characterized several plant esterases that hydrolyze these methylated plant hormones. The tobacco protein SABP2 had been originally identified as a SA-binding protein involved in plant defense responses, and I demonstrated that it is an esterase that hydrolyzes McSA to SA. Our results suggested that McSA may function as the long-sought mobile signal for the activation of the SA-dependent pathogen-induced defense responses in plants. The genome of Arabidopsis contains 20 genes encoding enzymes homologous to SABP2. I have shown that several of these enzymes can hydrolyze McIAA in vitro, and that at least one such esterase is capable of hydrolyzing McIAA in vivo to the active hormone IAA. My results suggested that McIAA itself does not possess hormonal functions. Overall, my work contributed to the discoveries and the elucidation of the role of methylated plant hormones, and helped to understand the mechanism by which hormone homeostasis is maintained.