Bradford Scholars is the University of Bradford online research archive. Access is free to anyone interested in research being conducted at Bradford. In the repository you will find a range of materials from journal articles and conference papers to research reports and theses.

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  • Relative Bio-Equivalence of Salbutamol MDIs Without and With the Attached Spacers. Development and validation of novel HPLC methods for the determination of salbutamol (and terbutaline) in urine excreted post-inhalation for bioequivalence and pharmacokinetic studies of Salbutamol MDIs

    Assi, Khaled H.; Paluch, Krzysztof J.; Mazhar, Syed H.R. (University of BradfordSchool of Pharmacy and Medical Sciences, 2018)
    This research explored in-vitro and in-vivo performance of three salbutamol metered dose inhalers (MDIs): Ventolin Evohaler (Evo), Airomir (Airo) and Salamol. In the in-vitro studies, critical quality attributes of the MDI using an Andersen cascade impactor (ACI) were examined and included measurement of fine particle dose (FPD) and total delivered dose (TDD). Bioequivalence studies were conducted in humans using the urinary pharmacokinetic method. Post-inhalation urinary excretion of salbutamol in the first 0.5 hour (lung deposition, USAL0.5) and over 24 hours (total systemic bioavailability, USAL24) were compared to determine the bioequivalence of the MDIs. The spacers recommended for use with these inhalers were also studied, and charcoal block studies were performed to assess the extent of USAL0.5. The three MDIs had FPD (μg) of 78, 91 and 89, respectively; the latter pair was equivalent. Their USAL0.5 (6, 7 & 7 μg) was however not bioequivalent. These MDIs delivered equivalent dose (177, 174 & 180 μg) which reflected on their USAL24 (101, 84 & 97 μg). Nevertheless, USAL24 was inequivalent between Evo and Airo. The FPD of Evo with Volumatic (VOL), AeroChamber Plus (AERO) and Able spacer was 78, 68 and 74 μg, respectively. The AERO treatment method was not equivalent to the MDI while VOL and Able were equivalent between them. Spacer USAL0.5 (16, 15 & 14 μg) was not bioequivalent to the MDI but to each other. The spacer in-vitro TDD (95, 85 & 92 μg) was inequivalent to the MDI treatment method. In contrast, their USAL24 was bioequivalent (97, 85 & 90 μg). The FPD of Airomir with AERO (95 μg) was in-vitro equivalent while USAL0.5 (15 μg) of this treatment method was bio-inequivalent to the MDI alone. On the contrary, the TDD (110 μg) and USAL24 (84 μg) of AERO were respectively in-vitro inequivalent and bioequivalent to the MDI alone. The FPD (μg) of Salamol MDI alone and with VOL (84) and AERO (86) as well as between the spacers was equivalent. However, the USAL0.5 of the MDI was not bioequivalent to spacers (20 and 18 μg) despite being equivalent between the spacers. In contrast, the respective TDD (103 and 95 μg) of spacer treatment methods were in-vitro inequivalent to the MDI alone albeit having bioequivalent USAL24 (86 and 87 μg). The variations in the in-vitro performance of the three MDIs are most likely due to differences in their formulations and designs. As the performance metrics of the MDI influence lung deposition, substituting one MDI with another can have clinical implications. Although the spacers reduced in-vitro TDD of the MDI to about half, their use increased lung deposition by over two folds, the magnitude of which varied with the MDI and spacer type. Despite significant decrease in dose delivery, the total systemic bioavailability with the spacers was similar to that with the MDI alone. This systemic bioequivalence is more likely due to greater USAL0.5 with the spacers. The results of the charcoal block studies reinforced this outcome. The present study is unique as it used a clinically relevant salbutamol MDI dose (two puffs), assessed results for equivalence and analysed ACI deposition data further as stage groups. The deposition on adjacent ACI stages were grouped together as coarse, fine and extra-fine particle masses to identify their more likely deposition sites in the human respiratory tract. Moreover, this thesis describes highly sensitive and novel HPLC and SPE methods, developed and validated to quantify salbutamol in urinary and aqueous matrices. As the clinical effects of MDIs are related to their lung deposition, the current work emphasizes the importance of spacer use. Nevertheless, differences in dose delivery between spacers may have clinical consequences. Hence, only the specific spacer recommended for use with the MDI should be used.
  • Modelling and Optimization of Conventional and Unconventional Batch Reactive Distillation Processes. Investigation of Different Types Batch Reactive Distillation Columns for the Production of a Number of Esters such as Methyl Lactate, Methyl Decanoate, Ethyl Benzoate, and Benzyl Acetate using gPROMS

    Mujtaba, Iqbal M.; Rahmanian, Nejat; Aqar, Dhia Y. (University of BradfordFaculty of Engineering and Informatics, 2018)
    The synthesis of a number of alkyl esters such as methyl lactate, methyl decanoate, and ethyl benzoate via esterification in a reactive distillation is quite challenging. It is due to the complexity in the thermodynamic behaviour of the chemical species in the reaction mixture in addition to the difficulty of keeping the reactants together in the reaction section. One of the reactants (in these esterification reactions) having the lowest boiling point can separate from the other reactant as the distillation continues. This can result in a significant drop in the reaction conversion in a conventional reactive distillation whether it is a batch or a continuous column. To overcome this challenge, new different types of batch reactive distillation column configurations: (1) integrated conventional (2) semi-batch (3) integrated semi-batch (4) integrated dividing-wall batch distillation columns have been proposed here. Four esterification reaction schemes such as (a) esterification of lactic acid (b) esterification of decanoic acid (c) esterification of benzoic acid (d) esterification of acetic acid are investigated here. A detailed dynamic model based on mass, energy balances, chemical reaction, and rigorous thermodynamic (chemical and physical) properties is considered and incorporated in the optimisation framework within gPROMS (general PROcess Modelling System) software. It is found that for the methyl lactate system, the i-SBD operation outperforms the classical batch operations (CBD or SBD columns) to satisfy the product constraints. While, for the methyl decanoate system, the i-DWCBD operation outperforms all CBD, DWBD and sr-DWBD configurations by achieving the higher reaction conversion and the maximum product purity. For the ethyl benzoate system, the performance of i-CBD column is superior to the CBD process in terms of product quality, and conversion rate of acid. The CBD process is found to be a more attractive in terms of operating time saving, and annual profit improvement compared to the IBD, and MVD processes for the benzyl acetate system.
  • Localising Peacebuilding in South Sudan? A Case of Transitional Justice and Reconciliation

    Harris, David; Francis, David J.; Agwella, Martin O.L. (University of BradfordFaculty of Social Sciences, Division of Peace Studies, 2018)
    Despite the signing of the 2005 Sudan Comprehensive Peace Agreement that ended the two decades of South-North Sudan war; and the 2015 Agreement on the Resolution of the Conflict in South Sudan, to end the current civil war, armed conflicts persist in South Sudan. Two key inadequacies of the liberal peacebuilding model, applied to address modern conflicts in Africa and across the globe are its insistence on international justice instruments such as the International Criminal Court, and the failure to recognize the role of local approaches and to incorporate them into peacebuilding intervention policies. This has resulted in failures to address the grievances and bitterness of war affected people and to reconcile divided communities. This study examines the potential and limits of applying local approaches to post-conflict peacebuilding in South Sudan. Based on empirical data obtained through qualitative case study conducted in South Sudan over five months in 2016, the findings reveal that despite the wide use of local institutions and justice mechanisms, many challenges exist, that pose serious difficulties in solely applying these strategies to transitional justice. However, for the liberal peacebuilding model to address the root causes of internal conflicts and build sustainable peace, local strategies could provide a significant complementary contribution, since dealing with the past entails more than retribution and truth seeking. The study has wider implications in practical and theoretical considerations for ongoing armed conflicts in Africa and other parts of the world.
  • An investigation into the influence of personality factors on cultural intelligence and the direct and moderating effects of international experience

    Mohr, Alexander T.; Martinus, Richard (University of BradfordThe School of Management, 2018)
    Globalization has created tremendous opportunities for organizations, but also created challenges due to cultural diversity, highlighting the importance of cross-cultural competencies in becoming successful nowadays. Cultural Intelligence (CQ) has emerged as an important concept describing the individual capabilities needed to effectively interact across cultures. Utilizing the theory of evolutionary personality psychology, several relationships are predicted between certain personality traits and factors of CQ. In addition, social learning theory is applied to explain the expected relationships between international experience and CQ. Thirdly, several hypotheses are developed to investigate if international experience strengthens the relationship between certain personality traits and elements of CQ. Based on a sample size of 197 employees from a financial services company, exploratory and confirmatory factor analyses validate the theorized four-factor CQ model. The results, based on stepwise regression analyses, confirm the expected relationship between international experience and all factors of CQ, except BCQ. In addition, the results reveal several significant relationships between personality factors and CQ. Novel for the research on CQ is the confirmation of several significant correlations between “dark-side“ personality traits (which have been characterized as ineffective behaviours) and elements of CQ. This study also shows several moderating relationships, providing new insights and posing important questions for future research, contributing to the accumulating literature on CQ. In addition, the results of this study provide interesting suggestions for practice, emphasizing the importance of adapting Human Resources policies to recruit, enable and retain those employees who are likely to successfully grasp the opportunities that globalization offers. In order to achieve this, organizations should rely on a broad range of assessment and development tools, focussing on CQ, personality traits and previous international experience, when selecting and preparing individuals for cross-cultural careers.
  • Submerged flexible vegetation impact on open channel flow velocity distribution: An analytical modelling study on drag and friction

    Pu, Jaan H.; Hussain, Awesar; Guo, Yakun; Vardakastanis, Nikolaos; Hanmaiahgari, P.R.; Lam, Dennis (2019)
    In this paper, an analytical model that represents the streamwise velocity distribution for open channel flow with submerged flexible vegetation is studied. In the present vegetated flow modelling, the whole flow field has been separated into two layers vertically: a vegetated layer and a non-vegetated free-water layer. Within the vegetated layer, an analysis of the mechanisms affecting water flow through flexible vegetation has been conducted. In the non-vegetated layer, a modified log-law equation that represents the velocity profile varying with vegetation height has been investigated. Based on the studied analytical model, a sensitivity analysis has been conducted to assess the influences of the drag and friction coefficients on the flow velocity. The investigated ranges of drag and friction coefficients have also been compared to published values. The findings suggest that the drag and friction coefficient values are non-constant at different depths and vegetation densities, unlike the constant values commonly suggested in literature. This phenomenon is particularly clear for flows with flexible vegetation, which is characterised by large deflection.

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