The University of Sydney
  • Sydney, Australia
Recent publications
No previous research has examined age and sex differences in balance outcomes in individuals with chronic obstructive pulmonary disease (COPD) at risk of falls. A secondary analysis of baseline data from an ongoing trial of fall prevention in COPD was conducted. Age and sex differences were analyzed for the Berg Balance scale (BBS), Balance Evaluation System Test (BEST test) and Activities-specific Balance Confidence Scale (ABC). Overall, 223 individuals with COPD were included. Females had higher balance impairments than males [BBS: mean (SD) = 47 (8) vs. 49 (6) points; BEST test: 73 (16) vs. 80 (16) points], and a lower confidence to perform functional activities [ABC = 66 (21) vs. 77 (19)]. Compared to a younger age (50-65 years) group, age >65 years was moderately associated with poor balance control [BBS (r = - 0.37), BEST test (r = - 0.33)] and weakly with the ABC scale (r = - 0.13). After controlling for the effect of balance risk factors, age, baseline dyspnea index (BDI), and the 6-min walk test (6-MWT) explained 38% of the variability in the BBS; age, sex, BDI, and 6-MWT explained 40% of the variability in the BEST test; And BDI and the 6-MWT explained 44% of the variability in the ABC scale. This study highlights age and sex differences in balance outcomes among individuals with COPD at risk of falls. Recognition of these differences has implications for pulmonary rehabilitation and fall prevention in COPD, particularly among females and older adults.
Endosex, in contrast to intersex, refers to innate physical sex characteristics judged to fall within the broad range of what is considered “usual for binary female or male bodies by the medical field,” or to persons with such characteristics [1] (p. 437). In this short contribution, we explain the origins and increasing use of this little-known term and discuss its practical and ethical relevance to medicine as well as to scholarship from a range of disciplines concerned with individuals’ sexed embodiment.
The gut microbiome has been implicated in polycystic ovary syndrome (PCOS) pathophysiology. PCOS is a disorder with reproductive, endocrine and metabolic irregularities, and several studies report that PCOS is associated with a decrease in microbial diversity and composition. Diet is an important regulator of the gut microbiome, as alterations in macronutrient composition impact the balance of gut microbial communities. This study investigated the interplay between macronutrient balance and PCOS on the gut microbiome of control and dihydrotestosterone (DHT)-induced PCOS-like mice exposed to diets that varied in protein (P), carbohydrate (C) and fat (F) content. The amount of dietary P, C and F consumed significantly altered alpha (α) and beta (β) diversity of the gut microbiota of control and PCOS-like mice. However, α-diversity between control and PCOS-like mice on the same diet did not differ significantly. In contrast, β-diversity was significantly altered by PCOS pathology. Further analysis identified an operational taxonomic unit (OTU) within Bacteroides (OTU3) with 99.2% similarity to Bacteroides acidifaciens, which is inversely associated with obesity, to be significantly decreased in PCOS-like mice. Additionally, this study investigated the role of the gut microbiome in the development of PCOS traits, whereby PCOS-like mice were transplanted with healthy fecal microbiota from control mice. Although the PCOS gut microbiome shifted toward that of control mice, PCOS traits were not ameliorated. Overall, these findings demonstrate that while diet exerts a stronger influence over gut microbiota diversity than PCOS pathology, overall gut microbiota composition is affected by PCOS pathology.
This paper presents the results of 81 experimental tests on the design strength of power-actuated fasteners (PAFs) in single shear connections for a light gauge steel framing (LGSF), as an alternative to self-drilling screws for selective uses. This type of connection can be employed to install a reinforcing plate on one or both sides of the frame, to connect steel strap cross bracing to framing, as well as for many other applications. These power-actuated fasteners present a very efficient and practical solution which can increase productivity and work quality by replacing time consuming screw connections. In this study, two different steel grades (G300 and G550), along with three different steel sheet configurations were investigated. Modes of failure for both the PAFs and the connected material were examined so to provide an understanding of the structural performance of nailed single lap connections and develop design recommendations and proposed formulae. The investigation covers a wide range of steel gauges (0.75 mm, 0.95 mm and 1.15 mm), commonly used in LGSF residential and commercial applications. Two groups of tests were performed. The first group of tests was conducted to determine the shear strength of connectors with two types being tested. The second tests series were carried out in various steel grade and gauge configurations for assembled connections. The results of this research and the proposed design formula can be used to establish the strength prediction model for power-actuated fasteners (PAFs) embedded into LGSF.
Sandy beaches in estuaries and bays (BEBs) are ubiquitous around the world. While some are referred to as “low energy” beaches, there are large differences in wave climate due to fetch, swell exposure and shoreface morphology. In this study, wave-climate controls on BEB morphology are identified relative to bay geometry and focusing on the relative contributions of wind, ocean swell and infragravity waves to the wave signature of a BEB. We focus on two swash-aligned and two drift-aligned BEBs in an urbanized, semi-enclosed bay in SE Australia (Kamay/Botany Bay), with differences in proximity to the bay mouth, beach aspects and fetch, as well as different histories of storm erosion and recovery. Spectral analysis of local wave measurements (June 2018–January 2019) shows that wave signatures at all 4 BEBs are dominated by swell waves (>51%), followed by locally generated wind waves at 3 out of 4 BEBs (<43%), then infragravity waves (<35%). We identified five weather scenarios based on local wind speed/direction and resultant wind waves, combined with infragravity waves, and offshore swell wave conditions. BEBs close to the bay entrance are primarily controlled by swell waves, but at times even BEBs close to the entrance can be sheltered from swell waves depending on their incident angle. Conversely, BEBs farthest from the bay entrance (~8 km) alternated between periods where spectra were dominated by either wind waves or offshore swells. Infragravity waves were only important relative to wind waves and swell at the most sheltered BEBs, where there is limited fetch and swell dissipated over shallow areas. We also show that anthropogenic factors such as constructed revetments or groynes significantly alter wave signatures at BEBs in this bay. Thus, wave spectral signatures are highly variable across BEBs in the same bay and can represent a simple tool to study BEB morphodynamics including storm response and subsequent recovery.
The insertion sequence IS 26 has long been known to play a major role in the recruitment of antibiotic resistance genes into the mobile resistance gene pool of Gram-negative bacteria and IS 26 also plays a major role in their subsequent broad dissemination. Related IS, IS 431/257 and IS 1216 are important in the same roles in Gram positive bacteria. However, until recently the properties of IS 26 movement that could potentially explain this ability had not been explored. A much needed insight has come from our recent demonstration that IS 26 uses a novel targeted mechanism that is conservative. The targeted conservative mechanism is much more efficient than the known replicative mechanism, which is now more accurately called copy-in. A recent review “The IS 6 family, a clinically important group of insertion sequences including IS 26 ” by Varani, He, Siguier, Ross and Chandler published in Mobile DNA has substantially misrepresented the recent studies on the targeted conservative mechanism and at the same time incorrectly implied that any mechanism established for IS 26 can be assumed to apply to a range of IS that are at best very distantly related. A few of the most important issues are examined in this comment. Readers are advised to consult the original literature to check facts before drawing firm conclusions.
Background Migraine is a neurological disorder characterized by intense, debilitating headaches, often coupled with nausea, vomiting and sensitivity to light and sound. Whilst changes in sensory processes during a migraine attack have been well-described, there is growing evidence that even between migraine attacks, sensory abilities are disrupted in migraine. Brain imaging studies have investigated altered coupling between areas of the descending pain modulatory pathway but coupling between somatosensory processing regions between migraine attacks has not been properly studied. The aim of this study was to determine if ongoing functional connectivity between visual, auditory, olfactory, gustatory and somatosensory cortices are altered during the interictal phase of migraine. Methods To explore the neural mechanisms underpinning interictal changes in sensory processing, we used functional magnetic resonance imaging to compare resting brain activity patterns and connectivity in migraineurs between migraine attacks ( n = 32) and in healthy controls ( n = 71). Significant differences between groups were determined using two-sample random effects procedures ( p < 0.05, corrected for multiple comparisons, minimum cluster size 10 contiguous voxels, age and gender included as nuisance variables). Results In the migraine group, increases in infra-slow oscillatory activity were detected in the right primary visual cortex (V1), secondary visual cortex (V2) and third visual complex (V3), and left V3. In addition, resting connectivity analysis revealed that migraineurs displayed significantly enhanced connectivity between V1 and V2 with other sensory cortices including the auditory, gustatory, motor and somatosensory cortices. Conclusions These data provide evidence for a dysfunctional sensory network in pain-free migraine patients which may be underlying altered sensory processing between migraine attacks.
Background The precise underlying mechanisms of migraine remain unknown. Although we have previously shown acute orofacial pain evoked changes within the brainstem of individuals with migraine, we do not know if these brainstem alterations are driven by changes in higher cortical regions. The aim of this investigation is to extend our previous investigation to determine if higher brain centers display altered activation patterns and connectivity in migraineurs during acute orofacial noxious stimuli. Methods Functional magnetic resonance imaging was performed in 29 healthy controls and 25 migraineurs during the interictal and immediately (within 24-h) prior to migraine phases. We assessed activation of higher cortical areas during noxious orofacial heat stimulation using a thermode device and assessed whole scan and pain-related changes in connectivity. Results Despite similar overall pain intensity ratings between all three groups, migraineurs in the group immediately prior to migraine displayed greater activation of the ipsilateral nucleus accumbens, the contralateral ventrolateral prefrontal cortex and two clusters in the dorsolateral prefrontal cortex (dlPFC). Reduced whole scan dlPFC [Z + 44] connectivity with cortical/subcortical and brainstem regions involved in pain modulation such as the putamen and primary motor cortex was demonstrated in migraineurs. Pain-related changes in connectivity of the dlPFC and the hypothalamus immediately prior to migraine was also found to be reduced with brainstem pain modulatory areas such as the rostral ventromedial medulla and dorsolateral pons. Conclusions These data reveal that the modulation of brainstem pain modulatory areas by higher cortical regions may be aberrant during pain and these alterations in this descending pain modulatory pathway manifests exclusively prior to the development of a migraine attack.
The accurate simulation of additional interactions at the ATLAS experiment for the analysis of proton–proton collisions delivered by the Large Hadron Collider presents a significant challenge to the computing resources. During the LHC Run 2 (2015–2018), there were up to 70 inelastic interactions per bunch crossing, which need to be accounted for in Monte Carlo (MC) production. In this document, a new method to account for these additional interactions in the simulation chain is described. Instead of sampling the inelastic interactions and adding their energy deposits to a hard-scatter interaction one-by-one, the inelastic interactions are presampled, independent of the hard scatter, and stored as combined events. Consequently, for each hard-scatter interaction, only one such presampled event needs to be added as part of the simulation chain. For the Run 2 simulation chain, with an average of 35 interactions per bunch crossing, this new method provides a substantial reduction in MC production CPU needs of around 20%, while reproducing the properties of the reconstructed quantities relevant for physics analyses with good accuracy.
Complex interventions, such as innovation platforms, pose challenges for evaluators. A variety of methodological approaches are often required to build a more complete and comprehensive understanding of how complex interventions work. In this paper, we outline and critically appraise a methodologically pluralist evaluation of an innovation platform to strengthen primary care for Aboriginal and Torres Strait Islander Australians. In doing so, we aim to identify lessons learned from the approach taken and add to existing literature on implementing evaluations in complex settings, such as innovation platforms. The pluralist design used four evaluation approaches—developmental evaluation, principles-focused evaluation, network analysis, and framework analysis—with differing strengths and challenges. Taken together, the multiple evaluation approaches yielded a detailed description and nuanced understanding of the formation, functioning and outcomes of the innovation platform that would be difficult to achieve with any single evaluation method. While a methodologically pluralist design may place additional pressure on logistical and analytic resources available, it enables a deeper understanding of the mechanisms that underlie complex interventions.
Background We have previously shown that service-wide support can increase the odds of alcohol screening in any 2-month period in a cluster randomized trial of service-wide support to Aboriginal and Torres Strait Islander Community Controlled Health Services (ACCHS). Here we report an exploratory analysis on whether the resulting pattern of screening was appropriate. Aim: we assess whether that increase in screening was associated with: (i) increased first-time screening, (ii) increased annual screening, (iii) whether frequently screened clients fell into one of four risk categories as defined by national guidelines. Methods Setting and participants: 22 ACCHS; randomized to receive the support model in the treatment (‘early-support’) arm over 24-months or to the waitlist control arm. Intervention: eight-component support, including training, sharing of experience, audit-and-feedback and resource support. Analysis: records of clients with visits before and after start of implementation were included. Multilevel logistic modelling was used to compare (i) the odds of previously unscreened clients receiving an AUDIT-C screen, (ii) odds of clients being screened with AUDIT-C at least once annually. We describe the characteristics of a sub-cohort of clients who received four or more screens annually, including if they were in a high-risk category. Results Of the original trial sample, 43,054 met inclusion criteria, accounting for 81.7% of the screening events in the overall trial. The support did not significantly increase the odds of first-time screening (OR = 1.33, 95% CI 0.81–2.18, p = 0.25) or of annual screening (OR = 0.99, 95% CI 0.42–2.37, p = 0.98). Screening more than once annually occurred in 6240 clients. Of the 841 clients with four or more screens annually, over 50% did not fall into a high-risk category. Females were overrepresented. More males than females fell into high-risk categories. Conclusion The significant increase in odds of screening observed in the main trial did not translate to significant improvement in first-time or annual screening following implementation of support. This appeared to be due to some clients being screened more frequently than annually, while more than half remained unscreened. Further strategies to improve alcohol screening should focus on appropriate screening regularity as well as overall rates, to ensure clinically useful information about alcohol consumption. Trial Registration ACTRN12618001892202, retrospectively registered 16 November 2018 https://anzctr.org.au/Trial/Registration/TrialReview.aspx?ACTRN=12618001892202 .
Background Cannabidiol (CBD) has demonstrated anti-inflammatory, analgesic, anxiolytic and neuroprotective effects that have the potential to benefit athletes. This pilot study investigated the effects of acute, oral CBD treatment on physiological and psychological responses to aerobic exercise to determine its practical utility within the sporting context. Methods On two occasions, nine endurance-trained males (mean ± SD V̇O 2max : 57.4 ± 4.0 mL·min ⁻¹ ·kg ⁻¹ ) ran for 60 min at a fixed intensity (70% V̇O 2max ) (RUN 1) before completing an incremental run to exhaustion (RUN 2). Participants received CBD (300 mg; oral) or placebo 1.5 h before exercise in a randomised, double-blind design. Respiratory gases (V̇O 2 ), respiratory exchange ratio (RER), heart rate (HR), blood glucose (BG) and lactate (BL) concentrations, and ratings of perceived exertion (RPE) and pleasure–displeasure were measured at three timepoints (T1–3) during RUN 1. V̇O 2max , RER max , HR max and time to exhaustion (TTE) were recorded during RUN 2. Venous blood was drawn at Baseline, Pre- and Post-RUN 1, Post-RUN 2 and 1 h Post-RUN 2. Data were synthesised using Cohen’s d z effect sizes and 85% confidence intervals (CIs). Effects were considered worthy of further investigation if the 85% CI included ± 0.5 but not zero. Results CBD appeared to increase V̇O 2 (T2: + 38 ± 48 mL·min ⁻¹ , d z : 0.25–1.35), ratings of pleasure (T1: + 0.7 ± 0.9, d z : 0.22–1.32; T2: + 0.8 ± 1.1, d z : 0.17–1.25) and BL (T2: + 3.3 ± 6.4 mmol·L ⁻¹ , d z : > 0.00–1.03) during RUN 1 compared to placebo. No differences in HR, RPE, BG or RER were observed between treatments. CBD appeared to increase V̇O 2max (+ 119 ± 206 mL·min ⁻¹ , d z : 0.06–1.10) and RER max (+ 0.04 ± 0.05 d z : 0.24–1.34) during RUN 2 compared to placebo. No differences in TTE or HR max were observed between treatments. Exercise increased serum interleukin (IL)-6, IL-1β, tumour necrosis factor-α, lipopolysaccharide and myoglobin concentrations (i.e. Baseline vs. Post-RUN 1, Post-RUN 2 and/or 1-h Post-RUN 2, p ’s < 0.05). However, the changes were small, making it difficult to reliably evaluate the effect of CBD, where an effect appeared to be present. Plasma concentrations of the endogenous cannabinoid, anandamide (AEA), increased Post-RUN 1 and Post-RUN 2, relative to Baseline and Pre-RUN 1 ( p ’s < 0.05). CBD appeared to reduce AEA concentrations Post-RUN 2, compared to placebo (− 0.95 ± 0.64 pmol·mL ⁻¹ , d z : − 2.19, − 0.79). Conclusion CBD appears to alter some key physiological and psychological responses to aerobic exercise without impairing performance. Larger studies are required to confirm and better understand these preliminary findings. Trial Registration This investigation was approved by the Sydney Local Health District’s Human Research Ethics Committee (2020/ETH00226) and registered with the Australia and New Zealand Clinical Trials Registry (ACTRN12620000941965).
Compulsive exercise is linked with poorer treatment outcomes in people with eating disorder (EDs). High-performance athletes represent a growing and complex subcomponent of the broader ED population, and emergent evidence indicates that different conceptualisations of compulsive exercise are needed in this population. Existing randomised controlled trials in ED populations have demonstrated small treatment effects on compulsive exercise compared with control groups; however, athletes were sparsely sampled across these studies. Thus, the extent to which current treatments for compulsive exercise in EDs are also effective in high-performance athletes is unknown. For this opinion paper, we sought representation from high-performance sports leadership, someone with lived experience of both an ED and high-performance athletics, and ED clinical experts. We discuss the utility of recommending exercise abstinence in ED treatment with athletes, as well as a number of other treatment strategies with some evidence in other contexts for further consideration and research in this population. These include using mindfulness-based interventions as an adjunct to cognitive-behavioural therapies, using wearable technologies and self-reported fatigue to inform training decisions, and incorporating greater exercise variation into training programs. We also offer practical considerations for clinicians seeking to apply foundational elements of cognitive-behavioural interventions (e.g., exposure and response prevention, cognitive restructuring, behavioural experiments) into an ED treatment program for a high-performance athlete. Future research is needed to examine characteristics of pathological compulsive exercise in athletes and whether available treatments are both feasible and effective in the treatment of compulsive exercise in athletes with an ED.
Objective Menopausal status impacts risk for many health outcomes. However, factors including hysterectomy without oophorectomy and Menopausal Hormone Therapy (MHT) can mask menopause, affecting reliability of self-reported menopausal status in surveys. We describe a step-by-step algorithm for classifying menopausal status using: directly self-reported menopausal status; MHT use; hysterectomy; oophorectomy; intervention timing; and attained age. We illustrate this approach using the Australian 45 and Up Study cohort (142,973 women aged ≥ 45 years). Results We derived a detailed seven-category menopausal status, able to be further consolidated into four categories (“pre-menopause”/“peri-menopause”/“post-menopause”/“unknown”) accounting for participants’ ages. 48.3% of women had potentially menopause-masking interventions. Overall, 93,107 (65.1%), 9076 (6.4%), 17,930 (12.5%) and 22,860 (16.0%) women had a directly self-reported “post-menopause”, “peri-menopause”, “pre-menopause” and “not sure”/missing status, respectively. 61,464 women with directly self-reported “post-menopause” status were assigned a “natural menopause” detailed derived status (menopause without MHT use/hysterectomy/oophorectomy). By accounting for participants’ ages, 105,817 (74.0%) women were assigned a “post-menopause” consolidated derived status, including 15,009 of 22,860 women with “not sure”/missing directly self-reported status. Conversely, 3178 of women with directly self-reported “post-menopause” status were assigned “unknown” consolidated derived status. This algorithm is likely to improve the accuracy and reliability of studies examining outcomes impacted by menopausal status.
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Agisilaos Kourmatzis
  • School of Aerospace, Mechanical and Mechatronic Engineering
Cristobal Guillermo dos Remedios
  • Muscle Research Unit, Anatomy & Histology
Auriol Purdie
  • Sydney School of Veterinary Science
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