ORCID Profile
0000-0002-5900-1396
Current Organisations
University of Queensland
,
Royal College of Surgeons in Ireland
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Publisher: Wiley
Date: 11-2013
DOI: 10.1111/DAR.12077
Publisher: Elsevier BV
Date: 03-2018
DOI: 10.1016/J.ACTBIO.2018.01.037
Abstract: The incidence of fragility fractures is expected to increase in the near future due to an aging population. Therefore, improved tools for fracture prediction are required to treat and prevent these injuries efficiently. For such tools to succeed, a better understanding of the deformation mechanisms in bone over different length scales is needed. In this study, an experimental setup including mechanical tensile testing in combination with digital image correlation (DIC) and small/wide angle X-ray scattering (SAXS/WAXS) was used to study deformation at multiple length scales in bovine cortical bone. Furthermore, micro-CT imaging provided detailed information about tissue microstructure. The combination of these techniques enabled measurements of local deformations at the tissue- and nanoscales. The orientation of the microstructure relative to the tensile loading was found to influence the strain magnitude on all length scales. Strains in the collagen fibers were 2-3 times as high as the strains found in the mineral crystals for s les with microstructure oriented parallel to the loading. The local tissue strain at fracture was found to be around 0.5%, independent of tissue orientation. However, the maximum force and the irregularity of the crack path were higher when the load was applied parallel to the tissue orientation. This study clearly shows the potential of combining these different experimental techniques concurrently with mechanical testing to gain a better understanding of bone damage and fracture over multiple length scales in cortical bone. To understand the pathophysiology of bone, it is important to improve our knowledge about the deformation and fracture mechanisms in bone. In this study, we combine several recently available experimental techniques with mechanical loading to investigate the deformation mechanisms in compact bone tissue on several length scales simultaneously. The experimental setup included mechanical tensile testing in combination with digital image correlation, microCT imaging, and small/wide angle X-ray scattering. The combination of techniques enabled measurements of local deformations at the tissue- and nanoscales. The study clearly shows the potential of combining different experimental techniques concurrently with mechanical testing to gain a better understanding of structure-property-function relationships in bone tissue.
Publisher: Springer Science and Business Media LLC
Date: 07-11-2017
Publisher: Wiley
Date: 16-03-2023
DOI: 10.1002/HPJA.714
Abstract: Sexual violence is an important public health issue affecting significant numbers of university students across Australia and internationally. In response, online modules have been widely implemented and there is an urgent need to better understand their effectiveness. The aim of this study was to evaluate an online sexual violence prevention and response education module designed for and implemented in one Australian university. We used a mixed‐methods approach that included pre ost module completion surveys of key measures relating to sexual consent, being a bystander, and response to disclosures as well as knowledge of resources and support services. We conducted post module completion semi‐structured interviews. Results indicated potential effectiveness of the module on beliefs about sexual consent, confidence intervening when witnessing potentially harmful situations, willingness to report incidents, confidence supporting a peer who discloses an incident, and knowledge of support services. Qualitative results indicated support for the online module as an accessible, private and self‐paced tool for sexual violence education. Interactive, relevant and engaging content that can be applied in real‐life contexts was noted as key for effectiveness. This exploratory study suggests there may be potential for online modules to be effective, as one aspect of universities' sexual violence prevention and response strategies—particularly modules aimed at addressing primary, secondary and tertiary prevention. Further rigorous research is required to strengthen best practice in the development and implementation of online modules as part of whole‐of‐c us strategies. Universities across Australia and internationally are grappling with sexual violence response and prevention in light of high prevalence rates among students. Online modules may be one effective tool when implemented as part of a wider strategy.
Publisher: Springer Science and Business Media LLC
Date: 19-07-2019
Publisher: Elsevier BV
Date: 12-2022
Publisher: Elsevier BV
Date: 02-2015
Publisher: Wiley
Date: 10-05-2015
DOI: 10.1002/JBMR.2513
Abstract: Cannabinoid ligands regulate bone mass, but skeletal effects of cannabis (marijuana and hashish) have not been reported. Bone fractures are highly prevalent, involving prolonged immobilization and discomfort. Here we report that the major non-psychoactive cannabis constituent, cannabidiol (CBD), enhances the biomechanical properties of healing rat mid-femoral fractures. The maximal load and work-to-failure, but not the stiffness, of femurs from rats given a mixture of CBD and Δ(9) -tetrahydrocannabinol (THC) for 8 weeks were markedly increased by CBD. This effect is not shared by THC (the psychoactive component of cannabis), but THC potentiates the CBD stimulated work-to-failure at 6 weeks postfracture followed by attenuation of the CBD effect at 8 weeks. Using micro-computed tomography (μCT), the fracture callus size was transiently reduced by either CBD or THC 4 weeks after fracture but reached control level after 6 and 8 weeks. The callus material density was unaffected by CBD and/or THC. By contrast, CBD stimulated mRNA expression of Plod1 in primary osteoblast cultures, encoding an enzyme that catalyzes lysine hydroxylation, which is in turn involved in collagen crosslinking and stabilization. Using Fourier transform infrared (FTIR) spectroscopy we confirmed the increase in collagen crosslink ratio by CBD, which is likely to contribute to the improved biomechanical properties of the fracture callus. Taken together, these data show that CBD leads to improvement in fracture healing and demonstrate the critical mechanical role of collagen crosslinking enzymes.
Publisher: Springer Science and Business Media LLC
Date: 25-01-2018
DOI: 10.1038/S41598-018-19296-Z
Abstract: Osteoporosis, a prevalent metabolic bone disorder, predisposes in iduals to increased susceptibility to fractures. It is also, somewhat controversially, thought to delay or impair the regenerative response. Using high-resolution Fourier-transform infrared spectroscopy and small/wide-angle X-ray scattering we sought to answer the following questions: Does the molecular composition and the nano-structure in the newly regenerated bone differ between healthy and osteoporotic environments? And how do pharmacological treatments, such as bone morphogenetic protein 7 (BMP-7) alone or synergistically combined with zoledronate (ZA), alter callus composition and nano-structure in such environments? Cumulatively, on the basis of compositional and nano-structural characterizations of newly formed bone in an open-osteotomy rat model, the healing response in untreated healthy and ovariectomy-induced osteoporotic environments was fundamentally the same. However, the BMP-7 induced osteogenic response resulted in greater heterogeneity in the nano-structural crystal dimensions and this effect was more pronounced with osteoporosis. ZA mitigated the effects of the upregulated catabolism induced by both BMP-7 and an osteoporotic bone environment. The findings contribute to our understanding of how the repair processes in healthy and osteoporotic bone differ in both untreated and treated contexts and the data presented represents the most comprehensive study of fracture healing at the nanoscale undertaken to date.
Publisher: Wiley
Date: 03-2020
DOI: 10.1002/JOR.24632
Publisher: Springer Science and Business Media LLC
Date: 17-04-2015
DOI: 10.1007/S00223-015-9991-7
Abstract: The ovariectomized (OVX) rat model is well established in investigations of osteoporosis and osteoporotic therapies. Advent of techniques such as Fourier-transform infrared (FTIR) spectroscopy and small angle X-ray scattering (SAXS) facilitate characterization of bone composition and mineral structure, respectively, which are key determinants of bone strength. Limited publications exist on the implementation of these techniques in the OVX rat model. At 12 weeks of age, female Sprague-Dawley rats were either sham-operated (n = 6) or ovariectomized (n = 6) and sacrificed 18 weeks later. L2 lumbar vertebrae and proximal tibiae were assessed by µCT, FTIR and SAXS. Presence of extensive trabecular deterioration in the µCT data confirmed the onset of osteoporosis. FTIR compositional parameters were determined including measures of degree of mineralization, crystallinity, collagen maturity and acid phosphate content. Mineral crystal thickness was determined from the SAXS data using two approaches available in literature. Compositionally, a decline in the heterogeneity of acid phosphate content was observed while measures of crystallinity and collagen maturity remained unaltered. Using an iterative curve fitting method, OVX-induced increases in the mineral crystal thickness of 3.8 and 7.8 % (p < 0.05) were noted in the trabecular of the vertebra and tibia, respectively. In conclusion, implementation of FTIR and SAXS techniques in the OVX rat model, identified no significant compositional changes while substantiating thickening of the mineral crystals as a general structural feature of OVX-induced osteoporosis in rats.
Publisher: Elsevier BV
Date: 10-2013
DOI: 10.1016/J.BONE.2013.06.030
Abstract: Bone grafts are well-established in the treatment of fracture non-unions but union is still not always achieved. Harvesting autograft is associated with donor site morbidity and the available amount of bone is limited. Allograft is more easily obtained and available in greater quantities but lacks the osteoinductive characteristics of autograft. We have previously shown a synergistic effect of bone morphogenetic protein (BMP-7), systemic bisphosphonates and autograft. In the present study we hypothesized that the combination of allograft+BMP-7+systemic ZA is more effective than autograft alone, which is currently the most frequently used aid in augmenting fracture and non-union healing. Femoral osteotomies were performed on 82 male Sprague Dawley rats and fixed with intramedullary K-wires. The rats were randomized into 7 groups: (i) saline, (ii) autograft, (iii) allograft, (iv) allograft+BMP-7, (v) autograft+zoledronate (ZA), (vi) allograft+ZA and (vii) allograft+BMP-7+ZA. Autografts were harvested from the contralateral tibia. Allografts were obtained from donor rats and frozen. BMP-7 was administered locally in the form of a putty placed circumferentially around the osteotomy. At 2 weeks, the rats were injected with a single dose of either saline or ZA. The rats were sacrificed at 6 weeks and the femurs were evaluated using radiography, histology, μCT and three-point bending tests. Complete radiological healing was seen in all rats in the BMP-7 groups. The callus volume was larger and the calluses were denser with allograft+BMP-7+ZA than in all other groups (μCT, p<0.001). Mechanical testing yielded a substantially higher peak force with the allograft+BMP-7+ZA combination than all other groups (p<0.01, p<0.001). This was further reinforced in the 59% increase in the peak force observed in the osteotomized femurs of the allograft+BMP-7+ZA group compared to the control femurs (p<0.01), whereas significant decreases of 22-27% were observed in the saline or bone-graft alone groups (p<0.01, p<0.05). Thus our results suggest that allograft combined with the anabolic effect of BMP-7 and the anti-catabolic effect of zoledronate is more efficient than autograft alone.
Publisher: JMIR Publications Inc.
Date: 14-04-2023
DOI: 10.2196/41211
Abstract: Two important factors that prolong and exacerbate chronic noncancer pain (CNCP) and disability are low pain self-efficacy and loneliness. Yet, few interventions have shown long-term sustained improvements in pain self-efficacy, and there are no evidence-based treatments that target social connectedness in people living with CNCP. More effective and accessible interventions designed to target self-efficacy and social connectedness could ease the burden of CNCP. To co-design accessible interventions to increase pain self-efficacy, social connection, pain-related outcomes, and quality of life, this study explored patients’ interest and preferences for digital peer-delivered interventions for CNCP as well as implementation barriers and enablers. This cross-sectional mixed methods study was part of a larger longitudinal cohort study. Adult Australian residents (N=186) with CNCP diagnosed by a medical professional or pain specialist were included. Participants were initially recruited through advertising on professional pain social media accounts and websites. Questions examined whether patients were interested in digital peer-delivered interventions and their preferences for specific features (eg, Newsfeed). Pain self-efficacy and loneliness were assessed using validated questionnaires, and the association between these factors and interest in digital peer-delivered support was explored. Open-ended questions explored implementation barriers, enablers, and suggestions for consideration in intervention design. There was interest in accessing digital peer-delivered interventions, with almost half of the s le indicating that they would access it if it was available. Those who indicated an interest in digital peer interventions reported both lower pain self-efficacy and greater loneliness than those who were not interested. Intervention content that incorporated education, links to health services and resources, and delivery of support by peer coaches were the most frequently preferred intervention features. Three potential benefits were identified: shared experience, social connection, and shared pain management solutions. Five potential barriers were identified: negative focus on pain, judgment, lack of engagement, negative impact on mental health, privacy and security concerns, and unmet personal preferences. Finally, there were 8 suggestions from participants: moderation of the group, interest subgroups, professional-led activities, psychological strategies, links to professional pain resources, newsletter, motivational content, live streaming, and online meetups. Digital peer-delivered interventions were of particular interest to those with CNCP who had lower levels of pain self-efficacy and higher levels of loneliness. Future co-design work could tailor digital peer-delivered interventions to these unmet needs. Intervention preferences and implementation barriers and enablers identified in this study could guide further co-design and the development of such interventions.
Publisher: Springer Science and Business Media LLC
Date: 25-02-2016
DOI: 10.1007/S00223-016-0120-Z
Abstract: Despite the vast amount of studies focusing on bone nanostructure that have been performed for several decades, doubts regarding the detailed structure of the constituting hydroxyapatite crystal still exist. Different experimental techniques report somewhat different sizes and locations, possibly due to different requirements for the s le preparation. In this study, small- and wide-angle X-ray scattering is used to investigate the nanostructure of femur s les from young adult ovine, bovine, porcine, and murine cortical bone, including three different orthogonal directions relative to the long axis of the bone. The radially averaged scattering from all s les reveals a remarkable similarity in the entire q range, which indicates that the nanostructure is essentially the same in all species. Small differences in the data from different directions confirm that the crystals are elongated in the [001] direction and that this direction is parallel to the long axis of the bone. A model consisting of thin plates is successfully employed to describe the scattering and extract the plate thicknesses, which are found to be in the range of 20-40 Å for most s les but 40-60 Å for the cow s les. It is demonstrated that the mineral plates have a large degree of polydispersity in plate thickness. Additionally, and equally importantly, the scattering data and the model are critically evaluated in terms of model uncertainties and overall information content.
Publisher: Elsevier BV
Date: 05-2019
DOI: 10.1016/J.ACTBIO.2019.04.008
Abstract: Positron emission tomography (PET) is a form of nuclear imaging, which quantitatively assesses the metabolic activity through the uptake of radioactive tracers.
Publisher: JMIR Publications Inc.
Date: 19-07-2022
Abstract: wo important factors that prolong and exacerbate chronic noncancer pain (CNCP) and disability are low pain self-efficacy and loneliness. Yet, few interventions have shown long-term sustained improvements in pain self-efficacy, and there are no evidence-based treatments that target social connectedness in people living with CNCP. More effective and accessible interventions designed to target self-efficacy and social connectedness could ease the burden of CNCP. o co-design accessible interventions to increase pain self-efficacy, social connection, pain-related outcomes, and quality of life, this study explored patients’ interest and preferences for digital peer-delivered interventions for CNCP as well as implementation barriers and enablers. his cross-sectional mixed methods study was part of a larger longitudinal cohort study. Adult Australian residents (N=186) with CNCP diagnosed by a medical professional or pain specialist were included. Participants were initially recruited through advertising on professional pain social media accounts and websites. Questions examined whether patients were interested in digital peer-delivered interventions and their preferences for specific features (eg, Newsfeed). Pain self-efficacy and loneliness were assessed using validated questionnaires, and the association between these factors and interest in digital peer-delivered support was explored. Open-ended questions explored implementation barriers, enablers, and suggestions for consideration in intervention design. here was interest in accessing digital peer-delivered interventions, with almost half of the s le indicating that they would access it if it was available. Those who indicated an interest in digital peer interventions reported both lower pain self-efficacy and greater loneliness than those who were not interested. Intervention content that incorporated education, links to health services and resources, and delivery of support by peer coaches were the most frequently preferred intervention features. Three potential benefits were identified: i shared experience /i , i social connection /i , and i shared pain management solutions /i . Five potential barriers were identified: i negative focus on pain /i , i judgment /i , i lack of engagement /i , i negative impact on mental health /i , i rivacy and security concerns /i , and i unmet personal preferences /i . Finally, there were 8 suggestions from participants: i moderation of the group /i , i interest subgroups /i , i rofessional-led activities /i , i sychological strategies /i , i links to professional pain resources /i , i newsletter /i , i motivational content /i , i live streaming /i , and i online meetups /i . igital peer-delivered interventions were of particular interest to those with CNCP who had lower levels of pain self-efficacy and higher levels of loneliness. Future co-design work could tailor digital peer-delivered interventions to these unmet needs. Intervention preferences and implementation barriers and enablers identified in this study could guide further co-design and the development of such interventions.
Publisher: Springer Science and Business Media LLC
Date: 05-12-2016
No related grants have been discovered for Neashan Mathavan.