Impact of shear stress on vascular adaptations in humans. Large arteries are important for the delivery of blood and oxygen to organs such as the heart and brain. A primary physiological stimulus which controls the size and function of these crucial arteries is the magnitude of flow or, more accurately, shear force that the inner wall of the artery is exposed to. We have developed novel software which enables non-invasive assessment of arterial wall velocity, diameter and blood flow. We will ass ....Impact of shear stress on vascular adaptations in humans. Large arteries are important for the delivery of blood and oxygen to organs such as the heart and brain. A primary physiological stimulus which controls the size and function of these crucial arteries is the magnitude of flow or, more accurately, shear force that the inner wall of the artery is exposed to. We have developed novel software which enables non-invasive assessment of arterial wall velocity, diameter and blood flow. We will assess the impact of acute and chronic changes in wall flow and shear on arterial size and function. We will also develop new software which measures other aspects of artery wall behaviour. These basic human physiology studies have direct implications for assessment of artery health in humans.Read moreRead less
Visualising vascular adaptation at the micro-scale in humans. The project aims to investigate fundamental issues in the mechanisms underlying vascular remodelling. It plans to develop novel optical scanning techniques to acquire high-resolution images of the cutaneous microvasculature, alongside absolute blood flow quantification. These novel tools would allow us to visualise and quantify functional and structural adaptations in the microvasculature in response to physiological stimuli such as h ....Visualising vascular adaptation at the micro-scale in humans. The project aims to investigate fundamental issues in the mechanisms underlying vascular remodelling. It plans to develop novel optical scanning techniques to acquire high-resolution images of the cutaneous microvasculature, alongside absolute blood flow quantification. These novel tools would allow us to visualise and quantify functional and structural adaptations in the microvasculature in response to physiological stimuli such as heat exposure and exercise. The non-invasive tool aims to enable us to assess adaptations in microvasculature health, improving our understanding of cardiovascular diseases and type 2 diabetes and potentially reducing the impact of costly and debilitating morbidities such as nephropathy, neuropathy, retinopathy, impotence and skin ulceration.Read moreRead less
Defining the direct effects of exercise on arterial adaptation. Understanding the mechanisms responsible for the beneficial effects of exercise is fundamental to optimising the design of preventative programs aimed at healthy ageing. These experiments will contribute to our understanding of the direct effects of changes in blood flow and pressure during exercise on vascular adaptations in humans.
Brain temperature regulation in mammals: mechanisms and consequences. Mammals detect increases in body temperature predominantly in the brain. Counterintuitively many mammals selectively cool the brain during heat stress, which appears to defeat the mechanism for inducing cooling responses. We intend to investigate this apparent anomaly which we believe is concerned with optimizing water use in hot conditions. We will further investigate the source of water for evaporative cooling by panting and ....Brain temperature regulation in mammals: mechanisms and consequences. Mammals detect increases in body temperature predominantly in the brain. Counterintuitively many mammals selectively cool the brain during heat stress, which appears to defeat the mechanism for inducing cooling responses. We intend to investigate this apparent anomaly which we believe is concerned with optimizing water use in hot conditions. We will further investigate the source of water for evaporative cooling by panting and discover if there has been convergent evolution in thermoregulatory strategies in the eutherian and marsupial lineages. The data we collect will be used to support a new model for thermoregulation in mammals.
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The comparative physiology of oxygen delivery to the kidney. The kidney is in danger of hyperoxia because the kidney receives so much blood relative to its mass. It is proposed that shunting oxygen between arteries and veins substantially mitigates the risk of hyperoxia, but under certain circumstances shunting substantially increases the risk of kidney hypoxia. Using a combination of synchrotron and histological imaging, This project will carefully define the three-dimensional vasculature of th ....The comparative physiology of oxygen delivery to the kidney. The kidney is in danger of hyperoxia because the kidney receives so much blood relative to its mass. It is proposed that shunting oxygen between arteries and veins substantially mitigates the risk of hyperoxia, but under certain circumstances shunting substantially increases the risk of kidney hypoxia. Using a combination of synchrotron and histological imaging, This project will carefully define the three-dimensional vasculature of the renal cortex in several different species and interpret its functional significance using computational modeling. The outcome of this project will be a new understanding in the comparative physiology of oxygen transport and shunting in the kidney.Read moreRead less
Evaporative water loss and relative water economy in marsupials. Marsupials are an iconic element of the Australian fauna, so the robust physiological database we will establish has intrinsic educational and scientific value to Australians. We will provide important methodological and analytical advances at the cutting edge of physiological research. This project will sustain our leading role as marsupial physiologists in the international scientific community, contribute to the high-quality tra ....Evaporative water loss and relative water economy in marsupials. Marsupials are an iconic element of the Australian fauna, so the robust physiological database we will establish has intrinsic educational and scientific value to Australians. We will provide important methodological and analytical advances at the cutting edge of physiological research. This project will sustain our leading role as marsupial physiologists in the international scientific community, contribute to the high-quality training of research students, foster national and international collaboration, and generally enhance the scientific profile of Australia. Knowledge of a species' biology and its interactions with the environment are essential for conservation in the face of landscape modification and climate change.Read moreRead less
Calls and constraints: do male frogs signal direct benefits? There is international concern over recent declines and disappearances of many species of amphibians. Australia is a hotspot for declines, but causes of declines remain enigmatic. Approximately one quarter of Australia's 230 amphibian species breed in terrestrial situations, but processes such as salinity, wetland and urban developments and climate change are altering the hydrology of our landscape, and preventing the flood events nece ....Calls and constraints: do male frogs signal direct benefits? There is international concern over recent declines and disappearances of many species of amphibians. Australia is a hotspot for declines, but causes of declines remain enigmatic. Approximately one quarter of Australia's 230 amphibian species breed in terrestrial situations, but processes such as salinity, wetland and urban developments and climate change are altering the hydrology of our landscape, and preventing the flood events necessary for the completion of the lifecycle of many species. This research has important conservation implications because it examines the effects of variable moisture regimes on the physiology and reproductive behaviours of terrestrial breeding frogs.Read moreRead less
Sugar and water handling by honeyeaters and sunbirds. Honeyeaters are the major vertebrate pollinators in Australia, playing a vital role in maintenance of healthy ecosystems. These birds are faced with extreme physiological challenges due to their diet, ingesting 2-5 times their body mass in nectar to obtain their daily sugar requirement. Nectarivores are, consequently, masters at processing and assimilating sugars and water; comparative physiology of these charismatic birds will provide deep u ....Sugar and water handling by honeyeaters and sunbirds. Honeyeaters are the major vertebrate pollinators in Australia, playing a vital role in maintenance of healthy ecosystems. These birds are faced with extreme physiological challenges due to their diet, ingesting 2-5 times their body mass in nectar to obtain their daily sugar requirement. Nectarivores are, consequently, masters at processing and assimilating sugars and water; comparative physiology of these charismatic birds will provide deep understanding of sugar and water handling mechanisms. Understanding gut and renal physiology and morphology contributes to the broad base of knowledge required to address pathological and clinical conditions in man, and will enhance our ability to predict effects of environmental change on these birds.Read moreRead less
Physiology of oxygen transport in the mammalian kidney. This project aims to improve understanding of oxygen regulation in renal tissue and knowledge of the physiology of the kidney. The mammalian kidney receives more oxygen than it uses or needs, and yet renal tissue is commonly found to be hypoxic. This project proposes that oxygen transport to the renal tissue is limited by blood vessel surface area. The project expects to generate anatomical data currently missing from the renal physiology c ....Physiology of oxygen transport in the mammalian kidney. This project aims to improve understanding of oxygen regulation in renal tissue and knowledge of the physiology of the kidney. The mammalian kidney receives more oxygen than it uses or needs, and yet renal tissue is commonly found to be hypoxic. This project proposes that oxygen transport to the renal tissue is limited by blood vessel surface area. The project expects to generate anatomical data currently missing from the renal physiology community, and potentially change the accepted story of oxygen homeostasis in the kidney. This will provide significant benefits, such as the provision of the foundational physiological science behind a determinant of kidney health and its flow-on impact to quality of life.Read moreRead less
Coping with flooding: nutrient transport in oxygen-deprived roots. Flooding damages plants by reducing oxygen supply to roots. The project will study effects of low oxygen on nutrient transport by roots. Understanding root functioning during low oxygen will enhance knowledge of plant acclimation to soil water logging. The project will contribute to the National Goal of 'Responding to Climate Change and Variability'.