Crackle sounds are associated with a variety of lung disorders. Smoking is also associated with many of the changes in the lung and airways leading to crackles. However, studying crackles as an indication of pathologic changes related to cigarette smoking in the lung is an underdeveloped area of research which needs to be explored. This study was undertaken to investigate whether differences in the crackles' characteristics (duration of two cycle deflection (2CD) and number of crackles per breathing cycle (NCBC)) in the lung of smoking and non-smoking young adults could be found and to quantify these differences, if present, using a digital stethoscope and computer aided lung sound analysis (CALSA). Sixty male subjects (30 smokers and 30 non-smokers) with an average age of 26.6 years (SD ± 4.7) were recruited, drawn from students at the University of Southampton in the United Kingdom. The lung sound data were recorded on one occasion using a digital stethoscope connected to a laptop running MATLAB to record and store the lung sounds from seven anatomical sites on the chest. The 2CD and NCBC per site in 25 second recordings were calculated using data from each of the anatomical sites used for recording lung sounds (excluding the trachea). No statistically significant differences in NCBC per site were found between smokers and non-smokers at any anatomical location. The 2CD per site data revealed some statistically significant differences at both anterior sites (anterior left: F (2, 57) = 9.40, P = 0.00; anterior right: F (2, 57) = 9.51, P = 0.00)) and both lateral sites (middle left: F (2, 57) = 4.2, P = 0.02; middle right: F (2, 57) = 4.36, P = 0.02)). The hypothesis that lung crackle’s 2CD differ between smokers and non-smokers has been supported but the hypothesis that NCBC differ between smokers and non-smokers has not been supported.

Health can be influenced by a number of factors and there is evidence to suggest that environmental cues during early-life stages greatly affect disease susceptibility in adulthood. Incidences of bone disease are becoming increasingly prevalent and it is believed that bone health in later life may be determined during foetal and neonatal stages. Currently, surrogate measures of bone strength (bone mineral density and content) are used to assess the risk to fracture, but are acknowledged to predict only a proportion of clinical cases. Therefore, it is important to understand and develop supplementary fracture risk to augment traditional tools. There has been difficulty in characterising the mechanical strength and toughness of bone due to the complexity of the hierarchical structure and compositional material properties. The bone quality framework describes the material and structural contributions to bone mechanical performance and hence utilisation of parameters associated with these contributors, alongside conventional bone mass measurements through densitometry, may improve the accuracy of fracture risk assessment. A myriad of factors have been suggested to affect bone health and therefore the current challenge is to identify the most influential. At present, there lacks a model that fully describes how material and structural factors act together throughout the bone hierarchy to affect the mechanical properties and fracture toughness of a whole bone, as well as how environmental factors may adapt these features. Within this project the relationship between biological alterations in bone formation and how this adapts material and microscale architecture are explored, with a view to assess the effect on whole bone mechanics. An initial pilot study on the effect of maternal low dietary protein during pregnancy on second generation female rat bone health was conducted to establish methodological protocol. Specifically, this project investigated the effect of maternal vitamin D, a known contributory factor in bone health, on offspring skeletal development and health. It was hypothesised that cellular activity can influence organ-level bone properties through control of the bone matrix and that subtle environmental assaults, such as low maternal protein or vitamin D, can alter this highly regulated process. Results from measuring bone i) gene expression, ii) micromechanics, iii) composition, iv) architecture, v) fracture toughness and vi) whole-bone mechanics in murine models have shown increased expression levels to be significantly correlated to an increase in microindentation distances at multiple locations along the femur and a reduction in cortical bone thickness and mechanical competence at the femur diaphysis. In particular, Runx2 expression was indicative of bone structure and mechanics, emphasising the importance of exploring the link between biological and mechanical bone environments further to understanding skeletal development and health. Investigation into the effect of maternal low protein status during pregnancy on female second generation offspring bone health health at 70 days of age demonstrated no significant differences between low protein background and control rats. Although a trend of lower mean osteogenic gene expression levels, lower mean fracture toughness, lower mean maximum load in whole bone mechanical testing and increased micromechanical indentation distances were observed in low protein animals, no significance was reached suggesting no persistent change is present from grand-maternal dietary protein status in second generation offspring. The effect of vitamin D deficiency during in utero life on offspring bone development was subsequently assessed using this multi-disciplinary experiment strategy in rats. Although the importance of vitamin D in childhood and adulthood bone health is established, the role of vitamin D in utero towards post-birth bone health remains contentious. Vitamin D deficient offspring at 21 days of age (childhood) were observed to have reduced diaphyseal cross section area and reduced mechanical capability in males. No further differences were found in gene expression, composition or material properties and no differences were identified in females. At 140 days of age (adulthood), negligible differences were found between control and vitamin D depleted animals in any bone health outcomes. These results indicate vitamin D depletion during in utero life has limited impact on skeletal health of rats at 140 days old. Critically, the detrimental effects of bone caused by vitamin D depletion at 21 days of age in male rats appears to have been recovered in adulthood after resuming a vitamin D sufficient diet after birth. Therefore, these results suggest vitamin D suffciency during childhood is essential for skeletal development. In summary, these results highlight the importance of the relationship between bone biological mechanisms and bone structure/mechanics across different length scales. Appreciation of this link enables comprehension of how skeletal development is established and the consequent effect of any challenges caused by disease. Furthermore, uncovering the aetiology of bone disease will enable the development of improved prophylactic measures, diagnosis and therapeutic strategies.

Visual surveillance finds increasing deployment for monitoring urban environments. Operators need to be able to determine identity from surveillance images and often use face recognition for this purpose. Unfortunately, the quality of the recorded imagery can be insufficient for this task. This study describes a programme of research aimed to ameliorate this limitation. Many face biometrics systems use controlled environments where subjects are viewed directly facing the camera. This is less likely to occur in surveillance environments, so it is necessary to handle pose variations of the human head, low frame rate, and low resolution input images. We describe the first use of gait to enable face acquisition and recognition, by analysis of 3D head motion and gait trajectory, with super-resolution analysis. The face extraction procedure consists of three stages: i) head pose estimation by a 3D ellipsoidal model; ii) face region extraction by using a 2D or a 3D gait trajectory; and iii) frontal face extraction and reconstruction by estimating head pose and using super-resolution techniques. The head pose is estimated by using a 3D ellipsoidal model and non-linear optimisation. Region- and distance-based feature refinement methods are used and a direct mapping from the 2D image coordinate to the object coordinate is developed. In face region extraction the potential face region is extracted based on the 2D gait trajectory model when a person walks towards a camera. We model a looming field and show how this field affects the image sequences of the human walking. By fitting a 2D gait trajectory model the face region can then be tracked. For the general case of the human walking a 3D gait trajectory model and heel strike positions are used to extract the face region in 3D space. Wavelet decomposition is used to detect the gait cycle and a new heel strike detection method is developed. In face extraction a high resolution frontal face image is reconstructed with low resolution face images by analysing super-resolution. Based on the head pose and 3D ellipsoidal model the invalid low resolution face images are filtered and the frontal view face is reconstructed. By adapting the existing super-resolution the high resolution frontal face image can be synthesised, which is demonstrated to be suitable for face recognition. The contributions of this research include the construction of a 3D model for pose estimation from planar imagery and the first use of gait information to enhance the face extraction and recognition process allowing for deployment in surveillance scenarios.

Acrylic bone cement has been used for fixation of load-bearing orthopaedic implants for over five decades, and continues to be the 'gold standard' for elderly patients and those with systemic disease. Aseptic loosening remains a major indication for revision of cemented hip implants, and has been associated with mechanical degradation of the cement mantle via the initiation and coalescence of fatigue micro-cracks. Microstructural defects such as voids and agglomerates of radiopacifier particles have been implicated in this damage accumulation process. Improved understanding of the relative effects of these features on the mechanisms of fatigue crack initiation and failure within the cement is required in order to inform the development of more robust cement formulations and thus increase the longevity of the cement mantle in vivo. The present study utilised micro-computed tomography (μ-CT) and scanning electron microscopy (SEM), in conjunction with mechanical testing, to provide a systematic, quantitative assessment of the effect of cement formulation and microstructure (including voids and radiopacifiers) on the in vitro fatigue failure of four commercial, vacuum-mixed cement formulations. Results were compared with μ-CT data and fractographic analysis of an ex vivo cement specimen. This novel 'data rich' methodology enabled non-destructive, three-dimensional analysis of defect populations in terms of the size, morphology and spatial density of individual microstructural features, and the identification and characterisation of crack-initiating defects. The inclusion of barium sulphate as a radiopacifier was found to have a negative effect on the fatigue life of cement; radiopacifier particles showed a tendency to form numerous large agglomerates, which readily initiated fatigue cracks; furthermore, fatigue life scaled consistently with initiating defect size. In contrast, cement containing zirconium dioxide as a radiopacifier demonstrated superior fatigue performance, and failure in these cement formulations was dominated by crack initiation from voids. In all four cement formulations, void populations were found to be bi-modal, and the largest voids (> 0.5 mm equivalent spherical diameter) were surrounded by secondary satellite voids in both in vitro and ex vivo cement specimens. Extensive void formation was also noted in both moulded specimens and cement mixing gun stubs, in addition to ex vivo cement. Optimisation of cement formulations and vacuum-mixing techniques may therefore be advantageous in order to reduce the formation of barium sulphate agglomerates and large voids, and thus minimise their potential crack initiation effects in vivo.

No description available.

Static and dynamic balance are essential in daily and sports life. Many factors have been identified as influencing static balance control, two of which are carrying additional weight and localized muscle fatigue but their influence on dynamic balance in sport activities has not been fully established. Therefore, the aim of this thesis was to investigate the characteristics of dynamic balance in sport related activities, with specific reference to the influence of body mass changes and muscular fatigue. Study one: The objectives of study one (methodological study, n = 5) were to apply the extrapolated Centre of Mass (XCoM) method and other relevant variables (centre of pressure, CoP; Centre of Mass, CoM; shear forces, Fh; kinetic energy, KE; momentum, P; and angular impulse, AI) to investigate sport related activities such as hopping and jumping. Many studies have represented the CoP data without mentioning its accuracy so several experiments were done to establish the agreement between the CoP and the projected CoM in a static condition. It was found that there was an inaccuracy with the average difference about 4mm. This meant that the angular impulse could not be reliably calculated. Its horizontal component, representing the Friction Torque (Q), could be reliably computed for dynamic balance. The implementation of the XCoM method was found to be practical for evaluating both static and dynamic balance. The general findings were that the CoP, the CoM, the XCoM, Fh, and Qwere more informative than the other variables (e.g. KE, P, and AI) during static and dynamic balance. The XCoM method was found to be applicable to dynamic balance as well as static balance. Study 2: The objectives of study two (baseline study, n =20) were to implement Matlab procedures for quantifying selected static and dynamic balance variables, establish baseline data of selected variables which characterize static and dynamic balance activities in a population of healthy young adult males, and to examine any trial effects on these variables. The results indicated that the implementation of Matlab procedures for quantifying selected static and dynamic balance variables was practical and enabled baseline data to be established for selected variables. There was no significant trial effect. Recommendations were made for suitable tests to be used in later studies. Specifically it was found that one foot-tiptoes tests either in static or dynamic balance are too challenging for most participants in normal circumstances. A one foot-flat eyes open test was considered to be representative and challenging for static balance, while adding further vertical jump and landing tests (two feet flat and one foot flat vertical jump) to the horizontal jumping and hopping for dynamic balance was considered to be more representative of sports situations. The main differences between horizontal and vertical jumping were in anterior-posterior direction. Study 3: The objectives of study three (differentiation study, n =20) were to establish the influence of physical (external added weight) and neurophysiological (fatigue) factors on static and dynamic balance in sport related activities. This was typified statically by the Romberg test (one foot flat, eyes open) and dynamically by jumping and hopping in both horizontal and vertical directions. Statically, added weight increased body's inertia and therefore decreased body sway in anterior-posterior direction though not significantly. Dynamically, added weight significantly increased body sway in both mideo-lateral and anterior-posterior directions, indicating instability, and the use of the counter rotating segments mechanism to maintain balance was demonstrated. Fatigue on the other hand significantly increased body sway during static balance as a neurophysiological adaptation primarily to the inverted pendulum mechanism. Dynamically, fatigue significantly increased body sway in both mideo-lateral and anterior-posterior directions again indicating instability but with a greater use of counter rotating segments mechanism. Differential adaptations for each of the two balance mechanisms (inverted pendulum and counter rotating segments) were found between one foot flat and two feet flat dynamic conditions, as participants relied more heavily on the first in the one foot flat conditions and relied more on the second in the two feet flat conditions. Conclusion: Results from this thesis are expected to aid towards advancing the understanding of balance in sport related activities, and can provide a solid foundation for future work in this area. In particular, a method was established to assess static and dynamic balance, baseline data for these associations was provided, and differential adaptations to physical or neurophysiological constraints were found. Valuable associations between specific variables and the first two mechanisms of balance were demonstrated.

In obesity, lipids stored in muscle as lipid droplets (LDs) lead to accumulation of fatty acid (FA) metabolites and insulin resistance. This research involves development of immunofluorescence microscopy methods to generate novel information on the subcellular content and distribution of key enzymes that play a role in the underlying mechanisms. Chapters 3 and 4 describe visualisation of two lipid synthesising enzymes. Both are more abundant in type I muscle fibres. Chapter 5 reveals no differences between these enzymes in non obese and obese elderly women. Chapter 6 reveals that a key lipolytic enzyme (ATGL) has a higher content in type I fibres, but its activator does not. Chapter 7 describes visualisation of SNAP23 and reveals a high content at the plasma membrane and mitochondria and low content in LDs. Chapter 8 fails to observe a difference between obese and non obese elderly women in plasma membrane SNAP23, and therefore fails to confirm the hypothesis that LDs hijack SNAP23. However, obese women have less SNAP23 in mitochondria and this may limit FA oxidation. In conclusion this thesis describes several novel mechanisms by which obesity leads to accumulation of FA metabolites and insulin resistance. The developed methods will be a valuable novel tool for future diabetes research.

Hepatitis C Virus (HCV) is a global health problem, with over 170 million infected individuals worldwide. 70-80% of infected individuals develop progressive disease, and approximately 2% of these acquire hepatocellular carcinoma (HCC). HCV entry is dependent on tetraspanin CD81, scavenger receptor BI, and tight junction proteins claudin-1 and occludin. Tetraspanins are involved in multiple biological functions including cell-ECM adhesion and motility. An actin polymerization-dependent cell spread was observed upon ligation of CD81 on hepatoma cells. Importantly, HCV infection perturbed CD81-dependent cell spread, suggesting HCV infection may modulate CD81 function in hepatoma cells. Functional assays demonstrated that CD81 expression and HCV infection promote hepatoma cell motility. These findings allude to a link between HCV infection and associated HCC development. Establishment of a chronic infection demonstrates that HCV can escape from the host adaptive immune responses. We developed an in vitro cell culture system to monitor viral transmission in the presence of neutralizing antibodies (nAb). Separation of producer and target cells ablated nAb resistant transmission, suggesting that cell-cell contact was essential. Furthermore nAb resistant transmission was dependent upon all four co-receptors. These observations confirm HCV immune evasion by cell-to-cell transfer and have major implications for anti-glycoprotein targeted therapies.

CD4+ T cells play a key role in orchestrating adaptive immunity. Their activation requires antigen presentation via MHC II proteins on antigen presenting cells (APC). Exosomes are membrane vesicles released by various cell types including APCs. APC-derived exosomes are MHC class II-positive and can induce CD4+ T cell responses. MHC II delivery to the cell surface and/or exosomes might be influenced by tetraspanins, a family of transmembrane proteins. We have prepared exosomes derived from Epstein-Barr virus (EBV)-infected human B lymphoblastoid cell lines (LCLs) and shown by Western blotting and immunoelectron microscopy that they contain MHC class II and tetraspanins including CD63, CD81 and CD82. Such LCLs as well as LCL-derived exosomes can mediate immunologically specific recognition by MHC class II matched EBV antigen-specific CD4+ T cell clones when directly added to the T cells. Using shRNA, we have decreased CD63 expression in LCLs and had been studying the effect of such downregulation on LCL as well as LCL-derived exosome mediated antigen presentation. Despite an unaltered level of MHC II, CD63low LCLs showed to be hyperstimulatory. In spite of a similar depletion of CD63 in exosomes derived from CD63low LCLs, the CD4+ T cell stimulation by these exosomes was unaltered. In search for the mechanism of this phenomenon we found a higher level of exosome secretion by CD63low LCLs. We speculate that CD63 may influence T cell stimulation by exosome trafficking as well as exosome release.

Assaults on the Police continue to increase. Of particular concern is the threat of injury from edged weapons. Shootings remain rare. The Home Office has embarked on a program to provide all police officers with suitable body armour. Body armour has been on general issue to police officers in America for over twenty years and has a superb record in saving lives from shootings. Little is known about its ability to prevent serious stab wounds from knives, as this is a much less common threat in the American policing environment. Therefore the specification for armour for police use in this country must be set to provide protection against the threats in the UK policing environment. Current knife-resistance standards are based on animal experimentation and have not been examined by any other model. To understand the protective requirements of armour, it is necessary to understand the weapon threat, the assailant’s method of delivery, and the vulnerability of the target. The biophysics of human stabbing (the assailant’s method of delivery), is the subject of ongoing investigation, and is outwith the scope of this thesis. In this thesis, the history and development of body armour is reviewed. An overview of the materials and properties of modern armour is presented. To understand the threat, the epidemiology of assaults on police officers and civilians is described. To determine the ideal protective qualities of body armour for issue to the police, two studies are presented. The first is a retrospective cohort study of 500 civilian victims of penetrating injury. The frequency of wounding, and the severity of wounding by body region is plotted on anatomical charts. This will demonstrate the vulnerability, and hence the protection requirements of each body area to penetrating injury. No previous study has measured the depth of the internal organs from the skin. A CT study is presented. It describes the accessibility of the internal organs to the passage of a blade by measuring the shortest distances from the skin. By applying the results of these two studies to the location of the internal organs (which lie in fairly constant relation to surface anatomy landmarks), the ideal protective qualities of armour panels over corresponding areas of organ vulnerability are plotted. The case for adopting three levels of knife resistance protection is made. The ballistic protective requirements of body armour are discussed. Finally, proposals for zoned body armour are presented and ergonomic and production issues are described. The model presented in this thesis has been accepted in principle by the Police Scientific Development Branch of the Home Office with a view to establishing a zoned body coverage requirement for police body armour.