This collection contains the Doctoral and Masters by Research theses produced within the department.

Recent Submissions

  • Physiological responses during performance of the 15-metre Multistage Shuttle Run Test (15mMSFT), with reference to the Police Fitness Standards

    Manser, Andrew (University of ChesterUniversity of Chester, 2019-09-13)
    The objective of this review is to provide a broad outline of the research surrounding the validity and reliability of the 15-metre multi-stage fitness test (MSFT) for measuring the aerobic fitness of police officers. Maintenance of optimal cardiorespiratory fitness (CRF) in the emergency services is vital for health maintenance, injury prevention, and physical preparation for on-duty tasks. Police officers in England and Wales are required to attend annual fitness testing with minimal standards in place for entry into police safety training (PST). The current minimal standard is level 5:4, an estimated V̇O2max of 35ml·kg-1 ·min-1 , with the requirements increasing for specialist roles. This is assessed using the 15-metre MSFT previously developed and validated against laboratory obtained measures. Previous validation studies have compared the physiological responses between the 15-metre MSFT and training protocols for varying police roles. For example, Brewer, Buckle & Castle (2013) validated the level 5:4 standard by assessing the heart rate responses between the PST and level 5:4 of the 15-metre MSFT. Despite greater peak heart rate responses reported in the 15-metre MSFT (Peak heart rate: 175±13 b·min-1 vs. 152±12 b·min-1 ), the standard was maintained with concerns the aerobic fitness of police officers would be suboptimal for the role and below that of the general population. Using a similar methodology, the minimal entry requirements for 13 additional roles were developed and validated. However to date, the validity and reliability of the 15-metre MSFT has not been assessed using direct measures of gas analysis, previously relying on indirect measures to assess demands.
  • Quality Control Systems of Gum Arabic in Sudan

    Al-Assaf, Saphwan; Eldigair, Hashim, Y. (University of Chester, 2018-11)
    Gum arabic is the oldest tree gum exudate, and has been in use since 4000 BC. Currently, it is used as an emulsifier (E414) in a number of processes, such as producing sweets and soft drinks. This study examines local practices such as tapping, collecting, transporting, sorting, and storing in various production areas in Sudan. Furthermore, it also investigates statistical differences in the key variables such as moisture content, optical rotation, ash content, viscosity, pH, colour Gardner index, colour Lovibond and tannin content in various production regions in Sudan during four seasons, namely 2013, 2014, 2015 and 2016. This study offers originality as the first investigation to combine labour practices related to quality control systems in a Sudanese context, using both primary and secondary data. Primary data were obtained from survey questionnaires (n=413 out of 800) distributed, giving a response rate of 52%, using chain-referral sampling among gum arabic farmers, managers, supervisors, and stakeholders. In addition to the questionnaires, open-ended (interview) questions were distributed to stakeholders and experts, by employing maximum variation sampling (n=15 out of 20 questions distributed, providing a response rate of 75%). Other primary data, namely, analytical and experimental data, were obtained from Nopec Quality Control Laboratory in Khartoum, and from the Hydrocolloids Research Centre at the University of Chester. Secondary data (national production) was obtained from the Sudan Customs Corporation via the Gum Arabic Board in Sudan. The findings of the survey questionnaires generally reveal that most workers tend to (i) work for relatively long time in the gum arabic industry, (ii) are knowledgeable about quality control systems, and (iii) aware about the best methods for maintaining product quality, collecting and storing gum arabic (r=-0.821). Specifically, the strongest correlation coefficient (p=0.001) were found between the worker’s age and the duration of working in the gum arabic industry (r=0.655). That is, the older respondents tend to be male while younger respondents tend to be female (r=-0.623). In addition, the majority of respondents (r=0.476) were knowledgeable about the production areas of gum arabic in Sudan as well as the location of the main auction market in Al Obeid. The findings from expert interviews indicate that there are both facilitative and hindrance factors that affect gum arabic development; these are related to infrastructure, technology, socio-economy, and relevant institution. The hindrance factors are, inter alia, the existence of relatively higher taxes, inefficient transportation, outdated technology and inconsistent quality control systems used by various gum arabic processing companies. Conversely, there are also facilitative factors such as financial assistance (the sheilla system) for farmers from banks, regular training, and methodical improvement of tapping through the use of modernised tools. The most significant factor is the agreement by all interviewees that better quality control systems should be a key to the development of this product therefore, allowing the suppliers to offer a quality product rather than a commodity. The results of secondary data reveal an increase in export trends from 2012 to 2018, indicating continuous growth in the industry and in particular for Acacia seyal compared to the previously held standard of Acacia Senegal. Finally, the findings of the analytical data reveal that key variables while differ across the various production season, the quality of the material from a given production area does not differ significantly. This is the major finding of this study whereby using reliable supply chain, traceability system and quality control measurements it would be possible to supply gum arabic with certain characteristics suitable for a given application. In conclusion, the findings are useful addition to our knowledge and potentially of commercial impact.
  • Development, Digestibility and Oxidation Properties of LC3PUFA Nanoemulsion and Its Effects on Sensory Profile of Food

    Zhou, QiQian (University of Chester, 2019-02)
    The long chain omega-3 polyunsaturated fatty acids (LC3PUFA) in human diets are mainly derived from oily fish and fish oil based supplements. Currently, the consumption of oily fish in the UK is far below the recommended level. LC3PUFA's non-fish sources such as algal oil with DHA (docosahexaenoic acid) are particularly important for vegetarians, non-fish eaters, and pregnant women. In previous work, high DHA vegetative algal oil load 50% w/w was successfully used to develop an oil-in-water nanoemulsion system suitable for functional food enrichment. The aims of this study included to investigate the effect of selected emulsifiers on oil-in-water nanoemulsions of algal oil prepared using ultrasonic technology. To improve the stability and digestibility of nanoemulsions within an In vitro digestion model. To examine the oxidation stability of nanoemulsions of algal oil and bulk algal oil with composition and droplet size changes during a 5 weeks storage trial at a temperature of 4 °C, 20 °C and 40 °C respectively. To evaluate sensory properties and consumer acceptability of food products with the incorporation of resulted nanoemulsion and find out possible relationship between the sensory profile of foods and the characteristics of added nanoemulsion. Nanoemulsion of LC3PUFA algal oil was developed with selected 6% w/w emulsifiers, including Lecithin (LN), Tween 40 (TN), Tween 60, equal ratio of Tween 40 and lecithin (LTN), 50% w/w Algal oil and 44%w/w water using a homogenizer and ultrasound processor. The results show that the nanoemulsion has been stabilised with selected emulsifiers (LN, TN & LTN) and the smallest droplet size of nanoemulsion was obtained using the combination of lecithin and Tween 40 at ratio 50:50. The In vitro digestion experiments were conducted with a model of fed state gastric and duodenal digestion using method of Lin et al (2014). The results show that the omega-3 oil nanoemulsion (LE/TW 50:50) were stable over 60 min in the gastric phase, in contrast omega-3 nanoemulsion (LE 100%) was destabilised at the gastric phase in 60 min, in which the droplet size diameter was significantly larger than at the beginning of gastric phase (P ≤ 0.05). The droplet size, fatty composition and oxidised compounds were measured to compare bulk algal oil and nanoemulsions stabilised with lecithin (LN) and Tween 40 (TN) solely and in combination (LTN) over a storage period of 5 weeks at temperatures of 4, 20 and 40°C. The results show the droplet size of nanoemulsions had no significant changes for samples stored at tested temperatures over 5 weeks storage. There were no significant differences in DHA composition within the weeks and temperatures used. For the GCHS analysed results, the increase in temperature to 40 ºC and storage time had a significant effect on the development of propanal for all samples (P≤0.05). Nanoemulsions prepared with lecithin alone had significantly higher development of propanal in week 1 at both 40 ºC and 20 ºC (P≤0.05). Lecithin (sole and combination with Tween 40) had more significant increases in oxidised volatiles at 40°C, which may be due to the instability of linoleic acid found in lecithin molecules which located in the outer layer of the oil droplets. There were no significant increase in oxidised compounds from the beginning to the end of storage for all tested samples stored at 4 °C. The sensory testing was also conducted on white sauce incorporated with omega-3 nanoemulsions with selected emulsifiers and bulk algal oil. The results show that the sensory attributes and overall acceptability of foods enriched with omega-3 nanoemulsion were statistically significantly lower than that of control sample (P≤ 0.05). Overall, the smallest droplet size of nanoemulsion was achieved with combination of lecithin and Tween 40 at a ratio of 50:50 by using ultrasonic processor. The stability and digestibility of nanoemulsion with the combination of lecithin and Tween 40 was improved in an In vitro digestion approach. A storage period of 5 weeks and temperature have no significant effect on the droplet size of tested nanoemulsion samples. However, there is a significant increase of the oxidised volatiles at 40 °C for all samples. Sensory testing show the white sauce with nanoemulsion has a stronger fishy taste and less overall liking than with bulk oil, indicating the smaller drop size is more ready to spread and reach the sensors of the mouth.
  • Musculoskeletal Disorders in the Workplace: An examination of the underlying causes and contributory risk factors

    Fallows, Stephen; Gellatly, Pamela (University of Chester, 16/05/2018)
    Introduction The incidence of musculoskeletal disorders remain the most common single condition, by incidence, affecting the working population. This remains true even though the apparent historic causation of manual handling, has reduced significantly. Back pain alone has been termed a 20thcentury medical disaster, which has reverberated into the 21stcentury, with 85% of low back pain having no clear clinical diagnosis yet individuals continue to seek a clinical solution. Understanding pain remains as complex as ever with very little evidence to suggest progress. The overall scale and cost of MSDs in the workplace are not easily identifiable as objective and accurate data are rare. Other workplace incidence and costs are either, not recorded or not published, in documents or grey literature, that are generally only accessible to individual organisations on a regular basis. Objectives The epistemology of this thesis is complexity and the extent to which this influences outcomes. The trilogy of complexity considered includes: 1. The issues facing organisations in how they prevent and manage MSDs; 2. The individual’s perspective and what they understand about possible causation, their beliefs, fears and expectations; 3. The interface with clinical and non-clinical practitioners, and whether interventions provided, are beneficial to the individual. Consideration of the multiple perspectives that arise from the various influences affecting the organisation, the employees within that organisation and the practitioners, has been possible by the metaphoric use of a “bricolage” methodology, and suggests that the current medical model is no longer appropriate. Methods A mixed method research design comprising four studies was undertaken. Firstly, a retrospective quantitative study of data (n = 21,092) from benefits provided by four organisations followed by a qualitative case example study (n = 21) of supporting documents and clinical information. These studies then informed the need for a qualitative study (n= 9) symptomatic individuals who participated in a focus group and (n= 6) face-to-face interviews and finally a qualitative study of practitioners involved in the provision of treatment services to the participating organisations. The data from each study informed the others and the data merged with the findings from the literature review and common interventions. Conclusions A disparity was found between what has been identified in literature and what actually is considered in clinical practice. The healthcare industry operates in “silos” and this separation of disciplines is reflected in organisational management. The range of underlying risk factors, evident in modern society, which are affecting or may affect an individual’s future musculoskeletal health are not being addressed by the medical model, and practitioners require training, or need to work in a multidisciplinary team, if they are to improve long-term outcomes. This thesis discusses the complexity of the multifactorial nature of musculoskeletal health, and provides a framework to challenge current practice and promote a fundamental change in the way in we assess, and treat the range of MSDs including a move towards educating individuals to take personal responsibility.
  • Factors affecting the quality of Acacia senegal gums

    Al-Assaf, Saphwan; Hamouda, Yasir (University of Chester, 2017-04)
    Gum arabic is a natural gummy exudate from acacia trees and exhibits natural built-in variations commonly associated with hydrocolloids. This study is concerned with the determination of factors which could influence its properties and functionality. These factors include origin (location, soil type, rainfall), different collections, age of the trees and storage condition. Previous studies acknowledged the influence of some of these factors but somehow lack providing definitive answers to questions being asked by the end user and required for the development of Gum arabic industry in Sudan. Local knowledge as well as the various stages of gum collection and processing were reviewed in order to provide a clear background and the justification for the experimental design. In this study samples were collected from six plantations located in the west and east regions in Sudan. Samples were collected from trees of different age (5, 10, 15 and 20 years old) and also from different picking interval (1-4). Each sample was divided into three portions (UK, Khartoum and Port Sudan) and stored for 5 years in order to determine the effect of the respective location. Various analytical parameters (% loss on drying, Optical rotation, % protein, intrinsic viscosity, molecular weight and molecular weight distribution) were measured to fully characterise the gum samples and to determine their functionality (emulsification). The results obtained for all samples were consistent with those previously reported in the literature (see Chapter 4). The only exception, identified in a number of samples from the western region, is the high proportion (~30%) of high molecular weight fraction termed arabinogalactan-protein complex (AGP). The results clearly demonstrated significant variations between plantations located in western region compared with the eastern region. However, the variations between the plantations within the same region are statistically not significant. High values of % protein, viscosity, Mw and % AGP were obtained from the 1st pick, from both regions, and then significantly decreased thereafter to the fourth pick. Samples from west region in Sudan, from 1st and 2nd pick and from tree age (15) years gave the highest viscosity, molecular weight, % AGP and superior emulsification performance compared to other samples from different tree ages. The regression statistical analysis for the physiochemical properties correlation with emulsification performance demonstrated the role of % AGP to be the most influential factor followed by viscosity. The major finding of this study is the effect of storage condition on the properties and functionality of Acacia senegal. An increase in the molecular weight for all stored samples (for 5 years) irrespective of region was evident and statically significant. However, this increase was more prominent for samples from the western region compared to the eastern region. The AGP fraction was increased by the storage treatment up to 40% in Port-Sudan, 20% in Khartoum-Sudan and 15% in UK. The result clearly demonstrated that the temperature and humidity are the crucial factors to induce the natural maturation process in acacia gums. Statistical analysis (linear regression) suggested statistically significant models and equations to predict and explain the variations in the physiochemical and functional properties based on the environmental factors, picking set and age of the tree.
  • Exploring hygiene compliance in the small independent restaurant sector in Abu Dhabi

    Fallows, Stephen; Bonwick, Graham A.; Idriss, Johaina (University of Chester, 2017-10)
    Introduction: Food safety is widely recognised as one of the problems in the fight for improving public health. Many governments are trying to improve public health through reducing foodborne illnesses and setting the climate for implementing HACCP-based food safety management systems (FSMS). Following the global trend, Abu Dhabi Food Control Authority (ADFCA) launched the HACCP for Catering Project (2010 – 2014), which aimed at helping foodservice businesses, licensed in the Emirate of Abu Dhabi, in implementing HACCP-based FSMS. Purpose: The project team recognised the limited resources and the diversity in education levels, ethnic backgrounds, and number of languages spoken among managers/supervisors and food handlers, as points of concern in the small independent restaurant (SIR) subsector. Thus, the Salamt Zadna (SZ) initiative, a simplified FSMS, was developed to train SIRs on implementing a set of safe operating procedures to improve compliance with food safety laws and regulations. Previous studies in the GCC region have mainly focused on governments’ attempts to enhance public health by developing laws, regulations, and policies, and recounting the barriers to implementing food safety controls. Methodology: This thesis took a different approach to food safety issues in the GCC region. It is comprised of two studies, which were conducted in two groups of SIRs – seven SZ participants and five non-participants – licensed in Al Ain, a major city in the Emirate of Abu Dhabi. The first explored awareness and understanding of food safety, related laws, regulations, and policies, and attitudes towards ADFCA services and inspectors, among managers/supervisors, by interviewing them. The second examined the efficacy of SZ in improving food handlers’ food-safety behaviours by observing their conduct, and comparing between the two SIR groups. Results: The study indicated low levels of awareness and understanding of food safety, related laws, regulations, and policies, in both groups of managers/supervisors; regardless of whether or not they were SZ Cparticipants. Both groups of interviewees expressed both negative and positive attitudes towards ADFCA’s services and inspectors; sometimes by the same interviewees, within the same, or between the two groups. However, SZ participating SIRs were slightly more positive than their counterparts. Key results highlighted the low impact of SZ on changing food handlers’ behaviours, except in two areas; namely, the food handlers working in SZ-participating SIRs scored higher than the other group in handwashing and changing gloves between handling raw meats and other foods. Implications: This research adds a new dimension to the food safety profile of the UAE, since it is the first of its kind in the UAE and the region as a whole. Its originality opens the door for other researchers to increase the volume of research in this field, which would help in understanding and tackling the barriers to improving the food safety status in the country, as well as the region.
  • Vitamin D and cardiometabolic disease risk: A RCT and cross-sectional study

    Mushtaq, Sohail; Hughes, Stephen F.; Agbalalah, Tari (University of Chester, 2017-01-30)
    Given the strong evidence for a beneficial role of vitamin D in diabetes and CVD pathogenesis, and the prevalence of vitamin D deficiency, vitamin D supplementation has been advocated for the prevention of cardiometabolic disease. To provide information on the effects of 5,000IU (125µg) vitamin D3 on cardiometabolic risk, a double blind, RCT in a cohort of overweight and obese UK adult males with plasma 25(OH)D concentration < 75nmol/L for a duration of 8 weeks was conducted. To the best of my knowledge, this is the first RCT to investigate the effect of 5,000IU (125µg) vitamin D3 on cardiometabolic markers in vitamin D insufficient, non-hypertensive and non-diabetic overweight and obese adult males.
  • The effect of dietary components on non-haem iron absorption in healthy and iron-deficient women

    Mushtaq, Sohail; Ahmad Fuzi, Salma F. (University of Chester, 2017-02)
    Two clinical trials investigating the effect of modulating two dietary components, tea containing polyphenols and vitamin D aimed at improving non-haem iron absorption and iron status recovery, were carried out in a cohort of healthy and iron deficient UK women, respectively. Tea has been shown to be a potent inhibitor of non-haem iron absorption but it remains unclear whether the timing of tea consumption relative to a meal influences iron bioavailability, with limited published evidence, especially in human trials. The aim of the first study was to investigate the effect of tea consumption on non-haem iron absorption and to assess the effect of time interval of tea consumption on non-haem iron absorption relative to an iron-containing meal, in a cohort of healthy female participants using a stable iron isotope (57Fe).
  • A mixed methods study of the early development of childhood overweight and obesity: Understanding the process of infant feeding

    Thurston, Miranda; Perry, Catherine (University of Liverpool (University of Chester)University of Chester, 2013-03)
    Prevalence of overweight and obesity has increased in adult and child populations during the last two to three decades in both developed and developing countries. Childhood obesity is common in the United Kingdom and has become a major public health issue. There is a growing body of evidence to suggest that the development of overweight and obesity in children has its roots in early life, with evidence of increasing weight over time in pre-school children. The study explored the early development of overweight in infants in Halton, an area of Northwest England. It was a mixed methods study comprising a quantitative analysis of routinely collected infant weight data and a longitudinal qualitative study of the process of weaning. Phase one - patterns of weight in Halton infants: The retrospective quantitative study utilised birthweight, and weight and length/height at eight weeks, eight months and 40 months of age from Halton infants born between 1994 and 2006 (16,328 singleton births). Analysis of these data provided further evidence of the early development of overweight, and highlighted patterns of infant overweight at eight months of age not previously reported. Phase two - longitudinal qualitative study of the process of weaning: Given the findings of phase one, factors that may influence early weight gain were considered. Therefore, the second phase focussed upon weaning, which has been little researched in terms of the way in which mothers manage the process. The aim was to explore weaning as a social process, focussing on the experience, knowledge, perceptions and actions of mothers as they weaned, in order to consider whether this could shed light on infant growth and development in general and the early development of overweight in particular. A grounded theory approach was utilised. Twenty one women were recruited and interviewed antenatally and then up to three times after their babies were born. A total of 67 interviews took place. A grounded theory, or ‘plausible account’, of the weaning process was developed. The centrality of the baby, and the way in which mothers talk about following the lead of the baby as they wean was highlighted, along with the ways in which this focus may falter or shift because of the complexity of influences on mothers’ lives. The primacy of embodied knowledge, that is the knowledge that mothers built up through the experience of feeding and weaning their infant, and the significance of being a mother in terms of being an ‘authority’ on feeding and weaning, were evident. In addition, the limitations of providing information, such as the feeding and weaning guidelines, without taking account of the individual mother, infant and their context was indicated. This is how some mistrust of the advice of health professionals, and possibly other ‘health messages’ emerged, as mothers did not see the advice as appropriate to them, their infant, or circumstances. Mothers did recognise babies as ‘bigger’ or ‘smaller’, but through valuing weight and weight gain were particularly aware of having small babies, which may have limited their capacity for recognising the significance of early signs of overweight in their infants. Final conclusions: Using mixed methods in this study allowed a broad picture of patterns of weight and overweight in Halton infants, and what some of the contributory factors to those patterns might be, to emerge, than if a single research method had been used. A number of implications for policy and practice: at an individual level in terms of the way in which women are supported to feed and wean their babies; and at a population level in terms of the monitoring of weight, were identified.