Advanced photonic methodologies for the 'in vitro' manipulation of cellular systems

This thesis investigates the application of a variety of optical techniques for the manipulation of single cells and their local micro-environment. The methodologies developed provide enhanced control over a single cell under study affording exquisite spatial and temporal control over biological processes of interest. The work presented within the thesis can be split into three distinct categories. The first of these provides an investigation in light activated “caged” molecular probes. This work generated several new compounds which were then applied to providing control over processes involved in pain, mitochondrial intracellular signalling and memory processes in the central nervous system. Application of caged neurotransmitters then demonstrates the first in vitro wavelength orthogonal photolysis of biologically relevant substances. Such a technique has great potential in the study of fundamental interactions within the processes underpinning memory and cognitive function. Secondly the application of optical injection techniques for the introduction of membrane impermeable species of interest is presented. An exploration of laser sources and optical systems has yielded two new strategies for optical injection. The targeted introduction of fluorescent stains, nucleic acids and gold nanoparticles to the interior of live mammalian cells demonstrates the power of these techniques. Thirdly, an investigation in optical trapping and optical injection provides simplified micromanipulation techniqes for application to biological studies. The use of capillaries as reservoirs for reagents of interest has realised a procedure for the reduction of large-scale chemical assays to a single cell level in static flow. When this technique is combined with intelligent control over the trapping laser source’s temporal behaviour, the interaction with the sample under study can be tailored for biological amiability or sample ablation. In this way a single laser source can be employed for the optical trapping and nanosurgery of a biological sample. A final study is presented demonstrating initial results for the targeted optical injection of caged compounds into mammalian cells. This methodology draws on the strengths of optical injection and caging technologies and presents a significant step forward in the level of control afforded over a biological system under study by optical techniques. The studies presented highlight the level of control and flexibility afforded by the application of optical manipulation and excitation strategies. Such optical methodologies extend the photonic tools available for enhanced studies in the life sciences

Freshwater blue space, health and well-being: a multiscale investigation

There is growing evidence that exposure to bodies of water or ‘blue spaces’ can result in benefits to human health and well-being. However, most blue space and health research has focused on the health and well-being impact of exposure to coastal environments and freshwater blue spaces have received significantly less research attention. Understanding the potential health and well-being benefits of freshwater blue space exposure is vitally important as more than 50% of the global population live within 1km of a body of freshwater and as freshwater and coastal environments differ significantly in their physical and hydrological properties. This thesis aimed to use multiscale and multidisciplinary approaches to quantify the health and well-being impact of access and exposure to freshwater blue space in Scotland. Both qualitative and quantitative methods were adopted, including semi-structured interviews and focus groups (qualitative) and stated preference and national scale subjective health and well-being surveying (quantitative). The key thesis findings suggest Scotland’s freshwater blue spaces are important health-promoting assets. Specifically, living in neighbourhoods with high blue space availability was associated with lower uptake of antidepressant medication and self-reported visits to freshwater blue was associated with significant improvements in mental well-being. Furthermore, loch swimming can provide a wide variety of physical, social and mental well-being benefits. The thesis contains a number of novel contributions, including the first published studies to (i) quantify the non-market value of protecting lochside environments; (ii) combine national antidepressant prescribing and freshwater blue space availability data; (iii) establish the health and well-being impacts and risks of loch swimming; and (iiii) quantify the health and well-being benefits of spending time in different types of freshwater blue (e.g. lakes, rivers and canals). Collectively, the thesis findings suggest spending time in and around freshwater blue space can provide a variety of mental health and well-being benefits. It is, therefore, recommended that promoting freshwater blue space usage and accessibility receives greater consideration in urban planning and public health policy, both in Scotland and internationally. However, it is of critical importance that policies aiming to increase freshwater blue space access and usage ensure the health and well-being benefits offered by freshwater blue space are available to all

Freshwater blue space and population health: an emerging research agenda

Growing evidence suggests that access and exposure to water bodies or blue spaces can provide a variety of health and well-being benefits. Attempts to quantify these ‘blue-health’ benefits have largely focused on coastal environments, with freshwater blue spaces receiving far less attention despite over 50% of the global population living within 3 km of a body of freshwater and populations living in landlocked areas having limited coastal access. This critical review identifies opportunities to improve our understanding of the relationship between freshwater blue space and health and well-being and outlines key recommendations to broaden the portfolio of emerging research needs associated with the field of blue-health. Recognising fundamental distinctions in relationships between health outcomes and access and exposure to freshwater versus coastal blue space is critical and further research is required to determine the mechanisms that link exposure to freshwater blue space with tangible health outcomes and to understand how such mechanisms vary across a range of freshwater environments. Furthermore, methodological improvements are necessary as spatial approaches adopted to quantify access and exposure to freshwater blue space often fails to account for the unique physical characteristics of freshwater and come with a variety of limitations. Based on the findings of this review, a suite of research needs are proposed, which can be categorised into three broad themes: (i) establishing a freshwater blue-health methodological framework; (ii) advancing the empirical freshwater blue-health evidence base; and (iii) promoting freshwater blue-health opportunities. When taken together, these research themes offer opportunities to advance current understanding and better integrate freshwater blue space into the wider nature-health research agenda

Optically enhanced acoustophoresis

Regenerative medicine has the capability to revolutionise many aspects of medical care, but for it to make the step from small scale autologous treatments to larger scale allogeneic approaches, robust and scalable label free cell sorting technologies are needed as part of a cell therapy bioprocessing pipeline. In this proceedings we describe several strategies for addressing the requirements for high throughput without labeling via: dimensional scaling, rare species targeting and sorting from a stable state. These three approaches are demonstrated through a combination of optical and ultrasonic forces. By combining mostly conservative and non-conservative forces from two different modalities it is possible to reduce the influence of flow velocity on sorting efficiency, hence increasing robustness and scalability. One such approach can be termed "optically enhanced acoustophoresis" which combines the ability of acoustics to handle large volumes of analyte with the high specificity of optical sorting

Quantitative Analysis of Planar Laser-Induced Fluorescence Measurements in a Hypersonic Boundary Layer

Several quantitative measurements extracted from nitric oxide (NO) planar laser-induced fluorescence (PLIF) data obtained in a hypersonic boundary layer are reported: (a) off-body NO mole fraction; (b) surface heat flux; and (c) near-wall static temperature. The experimental data was obtained at NASA Langley Research Centers 31 in. Mach 10 air tunnel. NO was seeded into the flow through a spanwise slot on the surface of the 10 degree half-angle wedge model. An ultraviolet planar laser sheet was positioned perpendicular to the wedge surface, downstream of the seeding slot, to excite six fluorescence transitions. A method for extracting the relative NO mole fraction, based on spatial variations of the J= 0.5 PLIF signal, is presented. Combined with the principle of mass conservation, the absolute NO mole fraction is determined. These measurements were used to assess CFD diffusion modelling, correct previously reported PLIF thermometry results, and develop methods for NO-PLIF heat transfer measurements

Blue space exposure, health and well-being: Does freshwater type matter?

There is growing evidence that spending time in or around water bodies or ‘blue spaces’ can result in improved human health. To date, investigations of the health-promoting potential of blue space exposure have mostly focused on coastal environments. Despite their vital role in many urban landscapes, freshwater blue spaces have received less research attention and very little is known about the potential of different freshwater blue space types to impact health and well-being. This study used logistic and negative binomial regression modelling to quantify the association between proximity and exposure to different freshwater blue space types and general health and mental well-being in Scotland. A nationwide online panel survey (n = 1392) was used to determine how far respondents lived from lakes, rivers and canals and to establish how often they visited these blue spaces. Living within a ten minute walking distance of lakes, rivers or canals was not associated with greater general health or mental well-being. However, frequently visiting rivers and canals but not lakes, in the last month, was associated with greater mental well-being. Frequent green space visitation, but not blue space visitation, was associated with higher odds of reporting good general health. Taken together, our findings suggest that freshwater blue space exposure can provide mental well-being benefits. However, the provision of these benefits may vary among different freshwater blue space types. Understanding the health and well-being impact of different freshwater environments, therefore, offers opportunities for evidence-based policymaking to maximise the health-promoting potential of urban blue spaces

Effects of 7 days on an ad libitum low-fat vegan diet: the McDougall Program cohort

BackgroundEpidemiologic evidence, reinforced by clinical and laboratory studies, shows that the rich Western diet is the major underlying cause of death and disability (e.g, from cardiovascular disease and type 2 diabetes) in Western industrialized societies. The objective of this study is to document the effects that eating a low-fat (≤10% of calories), high-carbohydrate (~80% of calories), moderate-sodium, purely plant-based diet ad libitum for 7days can have on the biomarkers of cardiovascular disease and type 2 diabetes.MethodsRetrospective analysis of measurements of weight, blood pressure, blood sugar, and blood lipids and estimation of cardiovascular disease risk at baseline and day 7 from 1615 participants in a 10-day residential dietary intervention program from 2002 to 2011. Wilcoxon’s signed-rank test was used for testing the significance of changes from baseline.ResultsThe median (interquartile range, IQR) weight loss was 1.4 (1.8) kg (p 7.5% at baseline, the risk dropped to 5.5% (>27%) at day 7 (p < .001).ConclusionsA low-fat, starch-based, vegan diet eaten ad libitum for 7days results in significant favorable changes in commonly tested biomarkers that are used to predict future risks for cardiovascular disease and metabolic diseases

Freshwater Wild Swimming, Health and Well-Being: Understanding the Importance of Place and Risk

Spending time in or around bodies of water or ‘blue spaces’ can benefit human health and well-being. A growing body of evidence suggests immersion in blue space, e.g., participating in ‘wild’ swimming, can be particularly beneficial for both physical and mental health. To date, wild swimming and health research has primarily focused on the experience of individuals who swim in the sea. Empirical studies of the health-promoting potential of swimming in freshwater environments, such as lochs and lakes, are lacking, despite the popularity of this practice in many countries and the vastly different physical and hydrological properties of freshwater and coastal environments. The aim of this study was to explore the relationship between loch (lake) swimming and health and well-being for adults living in Scotland and determine the importance of perceptions of place and risk in this relationship. Semi-structured interviews were conducted with twelve wild swimmers who regularly swim in lochs in Scotland. Interview data were analysed thematically using Nvivo. The findings suggest loch swimming has a variety of health and well-being benefits that can be categorised over three domains of health: physical, mental and social. Of these domains, mental health benefits e.g., mindfulness promotion, resilience building and increasing one’s ability to listen to their body, were particularly prominent. Our findings also highlight important physical and hydrological characteristics of loch environments, e.g., calm water conditions (relative to the sea), which contribute to positive wild swimming experiences. Finally, the perceived risks of loch swimming and mitigation strategies for these risks are established. Collectively, our findings further support the notion that wild swimming is a unique health-promoting practice. Our findings also highlight differences (in terms of experience and perceived risk) between swimming in freshwater and coastal environments, which can inform public health and water management policy

Valuing inland blue space: A contingent valuation study of two large freshwater lakes

Water bodies, or blue spaces, offer a range of health and well-being benefits. Many of these benefits occur in waterside spaces and do not require direct water contact. For example, non-water based physical activity (e.g. walking and running) or reduced stress as a result of viewing water from a distance. However, research dedicated to understanding the economic impact of changes to freshwater ecosystems predominantly focuses on water-based recreation and water quality. As a result, the economic impacts of changes to waterside space are often overlooked. This study used the contingent valuation method to determine public preference for the protection of lakeside quality, in terms of lake views, path quality and lakeside access, at two large freshwater lakes in Scotland (Loch Lomond and Loch Leven). The aim of the study was to estimate willingness to pay among a sample of adults in Scotland (n = 1056) for the protection of lakeside quality. Results indicate that the majority of respondents are willing to pay for the preservation of lakeside quality at each lake. Based upon the most conservative estimates obtained, mean willingness to pay for the protection of lakeside quality was £12.06 per household per year at Loch Lomond and £8.44 at Loch Leven. These findings provide valuable economic data and suggest that changes to waterside space at destination water bodies have nationally important economic impacts. Greater consideration of the economic impact of changes to lakeside space is recommended in order to develop cost-effective and socially optimal water resource management policies at large freshwater lakes

Applying the Cry of Pain model as a predictor of deliberate self-harm in an early-stage adult male prison population

Purpose: Deliberate self-harming behaviour is more prevalent within the prison environment than in community samples, with those in the first weeks of imprisonment at greatest risk. Research in this area has been largely atheoretical and a unifying model may improve the predictability of assessment and the development of intervention approaches. This study applied William and Pollock’s (2001) Cry of Pain model as the theoretical process of deliberate self-harm in the early stages of imprisonment. Method: A prospective study of new arrivals at an adult male prison. Participants (n =181) completed questionnaires and it was hypothesised that the factors derived from the model (perceived stress, defeat, entrapment and absence of rescue factors) would be predictive of future deliberate self-harm. Prisoners with active psychosis and non-English speakers were excluded. All participants were followed up for four months for instances of self-harm. Eighteen participants engaged in self-harm during this period. Results: The Cry of Pain Model was supported in the analysis. Hierarchical binary logistic regression confirmed that all features of the model were supported as predictive of future self-harm in prison, even after controlling for previous self-harm, depression and hopelessness. Conclusion: The Cry of Pain model is supported as a predictive model for deliberate self-harm in prison. Suggestions are offered as to the impact on assessment and intervention directions in prison