202 research outputs found
Biosensors for detecting stress in developing embryos
No full textAbstract not availableMalcolm S. Purdey, Avishkar Saini, Hanna J. McLennan, Benjamin J. Pullen, Erik P. Schartner, Melanie L. Sutton-McDowall, Jeremy G. Thompson, Tanya M. Monro, Stephen J. Nicholls and Andrew D. Abel
An organic fluorophore-nanodiamond hybrid sensor for photostable imaging and orthogonal, on-demand biosensing
No full textOrganic fluorescent probes are widely used to detect key biomolecules; however, they often lack the photostability required for extended intracellular imaging. Here we report a new hybrid nanomaterial (peroxynanosensor, PNS), consisting of an organic fluorescent probe bound to a nanodiamond, that overcomes this limitation to allow concurrent and extended cell-based imaging of the nanodiamond and ratiometric detection of hydrogen peroxide. Far-red fluorescence of the nanodiamond offers continuous monitoring without photobleaching, while the green fluorescence of the organic fluorescent probe attached to the nanodiamond surface detects hydrogen peroxide on demand. PNS detects basal production of hydrogen peroxide within M1 polarised macrophages and does not affect macrophage growth during prolonged co-incubation. This nanosensor can be used for extended bio-imaging not previously possible with an organic fluorescent probe, and is spectrally compatible with both Hoechst 33342 and MitoTracker Orange stains for hyperspectral imaging.Malcolm S. Purdey, Patrick K. Capon, Benjamin J. Pullen, Philipp Reineck,
Nisha Schwarz, Peter J. Psaltis, Stephen J. Nicholls, Brant C. Gibson and
Andrew D. Abel
Small and medium agility dogs alter their kinematics when the distance between hurdles differs
No full textThere is currently a lack of research examining the health and welfare implications for competitive agility dogs. The aim of this study was to examine if jump kinematics and apparent joint angles in medium (351 mm - 430 mm to the withers) and small (< 350 mm to the withers) agility dogs altered when distances between consecutive upright hurdles differ. Dogs ran a course of nine hurdles; three set at 3.6 m apart; three at 4 m apart and three at 5 m apart. Both medium (P=0.044) and small (P=0.006) dogs landed closer to the hurdle when consecutive hurdles were set at 3.6 m apart, with small dogs jumping slower at this distance (P=0.006). Results indicate that jump kinematics, but not apparent joint angles, alter when the spacing between hurdles differs. These findings may have implications for the health and welfare of agility dogs and should be used to inform future changes to rules and regulations
Rationally designed probe for reversible sensing of zinc and application in cells
No full textData source: Supporting information, https://doi.org/10.1021/acsomega.7b00923Biologically compatible fluorescent ion sensors, particularly those that are reversible, represent a key tool for answering a range of fundamental biological questions. We report a rationally designed probe with a 6′-fluoro spiropyran scaffold (5) for the reversible sensing of zinc (Zn2+) in cells. The 6′-fluoro substituent overcomes several limitations normally associated with spiropyran-based sensors to provide an improved signal-to-background ratio and faster photoswitching times in aqueous solution. In vitro studies were performed with 5 and the 6′-nitro analogues (6) in HEK 293 and endothelial cells. The new spiropyran (5) can detect exogenous Zn2+ inside both cell types and without affecting the proliferation of endothelial cells. Studies were also performed on dying HEK 293 cells, with results demonstrating the ability of the key compound to detect endogenous Zn2+ efflux from cells undergoing apoptosis. Biocompatibility and photoswitching of 5 were demonstrated within endothelial cells but not with 6, suggesting the future applicability of sensor 5 to study intracellular Zn2+ efflux in these systems.Sabrina Heng, Philipp Reineck, Achini K. Vidanapathirana, Benjamin J. Pullen, Daniel W. Drumm, Lesley J. Ritter, Nisha Schwarz, Claudine S. Bonder, Peter J. Psaltis, Jeremy G. Thompson, Brant C. Gibson, Stephen J. Nicholls, and Andrew D. Abel
Fine aggregate resources in the greater Cape Town area
No full textIncludes bibliographical references.Fine aggregate resources in the Greater Cape Town area have historically been in abundant supply. This supply has been typically comprised of the extensive natural building sand deposits that are scattered throughout the region. However, over the past decade increasing concerns have been raised regarding their long-term availability. This concern has arisen from reports suggesting the diminishing reserves of naturally occurring fine aggregates, which have historically dominated the market, and are beginning to near the end of their reserve life. The research undertaken in this thesis was to assess the plausibility of this concern and ascertain an understanding as to the future supply of resources in the region. In order to address the issues raised, a comprehensive understanding of fine aggregates, their properties and their source are required. This was developed in a literature review, whereby this knowledge provided an understanding as to the type of material that is preferable for fine aggregate use. The findings highlights the importance of using a resource that possesses properties, which are most appropriate for its specific use. In terms of concrete, this is achieved through using materials which possess the following preferred properties: (1) round particle shape and smooth surface texture, (2) a wide range of particle sizes that are well distributed, and (3) a mineralogical composition that is relatively inert, thus is not deleterious in concrete. Additionally, a resource must be economically viable, and be exploited in a manner such that the development aims to safeguard the environment for the benefit of current and future generations. These concepts and principles were then applied to the subsequent study into the fine aggregate resources located within the greater Cape Town region
Biological Sensing of Nitric Oxide in Macrophages and Atherosclerosis Using a Ruthenium-Based Sensor
No full textMacrophage-derived nitric oxide (NO) plays a critical role in atherosclerosis and presents as a potential biomarker. We assessed the uptake, distribution, and NO detection capacity of an irreversible, ruthenium-based, fluorescent NO sensor (Ru-NO) in macrophages, plasma, and atherosclerotic plaques. In vitro, incubation of Ru-NO with human THP1 monocytes and THP1-PMA macrophages caused robust uptake, detected by Ru-NO fluorescence using mass-cytometry, confocal microscopy, and flow cytometry. THP1-PMA macrophages had higher Ru-NO uptake (+13%, p < 0.05) than THP1 monocytes with increased Ru-NO fluorescence following lipopolysaccharide stimulation (+14%, p < 0.05). In mice, intraperitoneal infusion of Ru-NO found Ru-NO uptake was greater in peritoneal CD11b+F4/80+ macrophages (+61%, p < 0.01) than CD11b+F4/80− monocytes. Infusion of Ru-NO into Apoe−/− mice fed high-cholesterol diet (HCD) revealed Ru-NO fluorescence co-localised with atherosclerotic plaque macrophages. When Ru-NO was added ex vivo to aortic cell suspensions from Apoe−/− mice, macrophage-specific uptake of Ru-NO was demonstrated. Ru-NO was added ex vivo to tail-vein blood samples collected monthly from Apoe−/− mice on HCD or chow. The plasma Ru-NO fluorescence signal was higher in HCD than chow-fed mice after 12 weeks (37.9%, p < 0.05). Finally, Ru-NO was added to plasma from patients (N = 50) following clinically-indicated angiograms. There was lower Ru-NO fluorescence from plasma from patients with myocardial infarction (−30.7%, p < 0.01) than those with stable coronary atherosclerosis. In conclusion, Ru-NO is internalised by macrophages in vitro, ex vivo, and in vivo, can be detected in atherosclerotic plaques, and generates measurable changes in fluorescence in murine and human plasma. Ru-NO displays promising utility as a sensor of atherosclerosis.Achini K. Vidanapathirana, Jarrad M. Goyne, Anna E. Williamson, Benjamin J. Pullen, Pich Chhay, Lauren Sandeman, Julien Bensalem, Timothy J. Sargeant, Randall Grose, Mark J. Crabtree, Run Zhang, Stephen J. Nicholls, Peter J. Psaltis, and Christina A. Bursil
The emerging role of glycans and the importance of sialylation in cardiovascular disease
No full textGlycosylation is the process by which glycans (i.e. ‘sugars’) are enzymatically attached to proteins or lipids to form glycoconjugates. Growing evidence points to glycosylation playing a central role in atherosclerosis. Glycosylation occurs in all human cells and post-translationally modifies many signalling molecules that regulate cardiovascular disease, affecting their binding and function. Glycoconjugates are present in abundance on the vascular endothelium and on circulating lipoproteins, both of which have well-established roles in atherosclerotic plaque development. Sialic acid is a major regulator of glycan function and therefore the process of sialylation, in which sialic acid is added to glycans, is likely to be entwined in any regulation of atherosclerosis. Glycans and sialylation regulators have the potential to present as new biomarkers that predict atherosclerotic disease or as targets for pharmacological intervention, as well as providing insights into novel cardiovascular mechanisms. Moreover, the asialoglycoprotein receptor 1 (ASGR1), a glycan receptor, is emerging as an exciting new regulator of lipid metabolism and coronary artery disease. This review summarises the latest advances in the growing body of evidence that supports an important role for glycosylation and sialylation in the regulation of atherosclerosis.Naomi E. Wattchow, Benjamin J. Pullen, Anuk D. Indraratnada, Victoria Nankivell, Arun Everest-Dass, Peter J. Psaltis, Daniel Kolarich, Stephen J. Nicholls, Nicolle H. Packer, Christina A. Bursil
Polyatomic molecular structure retrieval using laser-induced electron diffraction
No full textCitation: Pullen, M. G., Wolter, B., Le, A. T., Baudisch, M., Hemmer, M., Senftleben, A., . . . Biegert, J. (2015). Polyatomic molecular structure retrieval using laser-induced electron diffraction. 635(7). doi:10.1088/1742-6596/635/7/072051Laser-induced electron diffraction is a developing dynamical imaging technique that is already able to probe molecular dynamics at few-femtosecond temporal resolutions and has the potential to reach the sub-femtosecond level. Here we provide the recipe for the extension of the technique to polyatomic molecules and we demonstrate the method by extracting the structure of aligned and anti-aligned acetylene (C2H2). We show that multiple bond lengths can be simultaneously imaged at high accuracy including elusive hydrogen containing bonds. Our results open the door to the investigation of larger complex molecules and the realization of a true molecular movie. © Published under licence by IOP Publishing Ltd
Study sites off the coasts of New York (Rockaway Peninsula, Fire Island), New Jersey (Pullen and Long Beach islands), and Virginia (Cedar Island) USA, where we modeled piping plover habitat before and after Hurricane Sandy using a Bayesian network approach.
No full textStudy sites off the coasts of New York (Rockaway Peninsula, Fire Island), New Jersey (Pullen and Long Beach islands), and Virginia (Cedar Island) USA, where we modeled piping plover habitat before and after Hurricane Sandy using a Bayesian network approach.</p
The effects of resistance training on athletic motor skill competencies in secondary school children
No full textLeading health organisations and long-term athletic development models have identified the need to develop movement competencies in children and adolescents. The athletic motor skill competencies (AMSC) have been identified as key skills that form the foundations of all athletic movements. The AMSC form an integral part of the long-term athletic development of youth, and improving these qualities should be central to coaches working with young individuals. Multiple movement competency screens assess some aspects of AMSC, but there is no consensus regarding which screens may be most appropriate for a given cohort or coaching environment. Chapter 3 provides an evaluation of the movement screens available to assess various AMSC and in turn considers their reliability, feasibility, strengths, and weaknesses when used with youth populations. The resistance training skill battery (RTSB), athletic introductory movement screen (AIMS), and tuck jump assessment (TJA) were all deemed to be useful screens and were subsequently utilised throughout the thesis.
In Chapter 5 boys (n = 20) and girls (n = 26) aged 11-14 years old were part of a 7-week resistance training pilot study. The study examinedthe effects of delivering resistance training as part of the physical education curriculum on AMSC, physical performance, and psychosocial constructs (motivation to exercise, physical self-efficacy, and global self-esteem). Male and female intervention groups significantly improved RTSB (p > 0.05) whereas no changes were observed in the control groups. No changes were observed in the intervention groups TJA and only trivial and small non-significant changes in standing long jump performance. Significant increases in motivation of the male intervention group occurred. Resistance training integrated in physical education can improve AMSC in short-term interventions.
Chapter 6 examined the relationships between AMSC, maturation, sex, body mass index (BMI), physical performance, and psychological constructs (motivation to exercise, physical self-efficacy, and global self-esteem) in a large cohort of boys (n = 119) and girls (n = 105) aged 11-13 years old. Trivial to moderate strength relationships were evident between AMSC and BMI (boys: rs= −0.183; girls: rs= −0.176), physical performance (boys: rs= 0.425; girls: rs= 0.397), and psychological constructs (boys: rs= 0.130–0.336; girls rs= 0.030–0.260).
When the sample was divided into participants demonstrating higher and lower levels of competency (using the median split), higher levels of AMSC were related to significantly higher levels of physical performance (d = 0.25), motivation to exercise (d = 0.17), and physical self-efficacy (d= 0.15–0.19) in both boys and girls. AMSC have some associations with physical performance and psychological constructs. This may suggest that increasing AMSC could positively influence physical and psychological outcomes, but further research was needed to investigate this possibility.
Chapter 7 examined the effects of an 11-week resistance training intervention as part of the physical education curriculum on AMSC, physical performance, and psychological constructs linked to physical activity behaviours. Male (n = 40) and female (n = 48) intervention groups significantly improved AIMS(p > 0.05) whereas no changes were observed in the male (n = 33) and female (n = 35) control groups. Both male and female intervention groups significantly improved standing long jump performance in comparison to control groups (p> 0.05). Only trivial changes in TJA and psychological constructs were observed in both groups. Findings indicate resistance trainingintegrated in physical education is effective atimprovingAMSC and physical performance but did not improve psychological constructs in school children.
Chapter 8 presents a confessional tale with the primary researcher reflecting on some of the confounding influences to directing a successful intervention and the impact this can have on the researcher. The chapter reflects on experiences faced during the intervention presented in Chapter 6, uncovering some of the home truths about school-based interventions that are usually ignored such as pupil behaviour, teacher support, and implementing research into practice. Overall, this paper provides researchers with insights into the unexpected, and practitioners with suggestions to help navigate their own coaching interventions.</p
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