Bradford Scholars
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.
Contact the repository team via openaccess@bradford.ac.uk with any queries about Open Access or how to deposit your research papers.
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Publication Flexural performance of FRP-prestressed RPC beams reinforced with steel-FRP composite bars(Elsevier, 2025-03)Six reactive powder concrete (RPC) beams, reinforced with non-prestressed steel-FRP composite bars (SFCBs) and prestressed Fiber Reinforced Polymer (FRP) bars, were fabricated to investigate their flexural performance. Four-point bending tests were conducted on beams with different types of concrete, prestressing bars and prestress levels. The test results demonstrated that prestressing significantly enhances the flexural performance of the beams tested. Compared with non-prestressed RPC beams, FRP-prestressed RPC beams exhibited a 24%, 20%, and 17% improvement in cracking, yield, and ultimate loads, respectively, along with an 81% increase in energy absorption capacity and reduced crack widths, but an 8% reduction in ductility. FRP-prestressed RPC beams significantly outperformed their ordinary concrete counterparts, with cracking, yield, and ultimate moments improved by 104%, 77%, and 58%, respectively. Increasing the pre-tension stress of FRP bars enhanced the cracking moment and reduced deflection. However, higher prestress level leads to lower bearing capacity and energy absorption due to premature rupture of prestressed reinforcements before crushing of compression concrete. The type of prestressing reinforcement, whether FRP or steel, has little effect on the cracking moment but significantly affected ductility and energy absorption. Based on simplified material constitutive models and rational fundamental assumptions, two bending failure modes were identified for FRP prestressed RPC beams. Discriminant criteria for these modes of failure were established, along with simplified formulas for predicting the bearing capacity of the beams. These findings provide a technical reference for the design and application of FRP-prestressed RPC beams reinforced with SFCBs.Publication Oligo(styryl)benzenes liposomal AIE-dots for bioimaging and phototherapy in an in vitro model of prostate cancer(Elsevier, 2024-09-15)Whilst the development of advanced organic dots with aggregation-induced emission characteristics (AIE-dots) is being intensively studied, their clinical translation in efficient biotherapeutic devices has yet to be tackled. This study explores the synergistic interplay of oligo(styryl)benzenes (OSBs), potent fluorogens with an increased emission in the aggregate state, and Indocyanine green (ICG) as dual Near Infrared (NIR)-visible fluorescent nanovesicles with efficient reactive oxygen species (ROS) generation capacity for cancer treatment using photodynamic therapy (PDT). The co-loading of OSBs and ICG in different nanovesicles has been thoroughly investigated. The nanovesicles’ physicochemical properties were manipulated via molecular engineering by modifying the structural properties of the lipid bilayer and the number of oligo(ethyleneoxide) chains in the OSB structure. Diffusion Ordered Spectroscopy (DOSY) NMR and spectrofluorometric studies revealed key differences in the structure of the vesicles and the arrangement of the OSB and ICG in the bilayer. The in vitro assessment of these OSB-ICG nanovesicles revealed that the formulations can increase the temperature and generate ROS after photoirradiation, showing for the first time their potential as dual photothermal/photodynamic (PTT/PDT) agents in the treatment of prostate cancer. Our study provides an exciting opportunity to extend the range of applications of OSB derivates to potentiate the toxicity of phototherapy in prostate and other types of cancer.Publication Experimental assessment of using Phase Change Lightweight Aggregates to enhance the thermal storage of geo-energy structures(https://doi.org/10.1016/j.est.2023.109981, 2024-02-15)Geo-energy structures (GES) are mainly structural foundations that are used as heat exchangers to extract or dissipate heat from/to the ground, and they are progressively being adopted for providing more sustainable energy strategies in new buildings. Despite the fact that over one-third of a century has passed since the first installation of geo-energy structures in northern Europe, enhancing the thermal energy storage of those structures has not been thoroughly studied. This paper aimed to increase the thermal energy-storage of geo energy structures by incorporating phase change material–impregnated light-weight aggregates (PCM LWA'S) at the soil-structure interface. The results showed that the inclusion of 35 % PCM LWA's at the GES/soil interface extensively increased the temperature difference (inlet-outlet) for cooling and heating. It is also illustrated that the effect of PCM inclusion to enhance the thermal performance is more significant during the heating mode (PCM is cooled down) than during the cooling mode (PCM is heated up). Furthermore, the findings indicated that the use of PCM LWA's has reduced the thermal deformation of GES and has a positive impact on soil temperature and interference radius.Publication Indole-containing arene-ruthenium complexes with broad spectrum activity against antibiotic-resistant bacteria(2022-01-11)Antimicrobial resistant (AMR) bacteria are emerging and spreading globally, threatening our ability to treat common infectious diseases. The development of new classes of antibiotics able to kill or inhibit the growth of such AMR bacteria through novel mechanisms of action is therefore urgently needed. Here, a new family of indole-containing arene ruthenium organometallic compounds are screened against several bacterial species and drug resistant strains. The most active complex [(p-cym)Ru(O-cyclohexyl-1H-indole-2-carbothioate)Cl] (3) shows growth inhibition and bactericidal activity against different organisms (Acinetobacter baumannii, Mycobacterium abscessus, Mycobacterium tuberculosis, Staphylococcus aureus, Salmonella enterica serovar Typhi and Escherichia coli), demonstrating broad-spectrum inhibitory activity. Importantly, this compound series exhibits low toxicity against human cells. Owing to the novelty of the antibiotic family, their moderate cytotoxicity, and their inhibitory activity against Gram positive, Gram negative and acid-fast, antibiotic resistant microorganisms, this series shows significant promise for further development.Publication The damaging potential of pesticide formulations on human skin. A study of the damaging activity of commercial pesticide formulations and their components on the barrier function of human skin, and methods by which to reduce such damagePercutaneous absorption is the major route of pesticide entry into the body. Impairment of skin barrier function may increase systemic exposure and toxicological risk. This project examines barrier function impairment of human skin in vitro due to commercial liquid formulations of the pesticides pirimphos methyl and pirimicarb. Water permeation studies demonstrated stratum corneum damage due to emulsifiable concentrate formulations, damage being time and concentration dependent. The major excipient responsible was the divalent anionic surfactant Phenylsulphonate CA. Another divalent anionic surfactant Empicol ML26/F also caused stratum corneum barrier function impairment. Protection against anionic damage was achieved using polyoxyethylated nonionic surfactants of the Synperonic NP and PS ranges incorporated in mixtures and as stratum corneum pretreatments. Mechanisms of surfactant damage and protection were assessed. Both anionic surfactants were shown to partition into the stratum corneum, damage being related to the extent of partitioning. Differential scanning calorimetry showed that the anionic surfactants disrupt the intercellular lipid bilayer structure with a small effect on intracellular keratin. Therefore, molecular penetration through stratum corneum is principally enhanced via the intercellular route. Photon correlation studies evidenced micellar interaction of the anionic and nonionic surfactant molecules in aqueous solution. This may occur in stratum corneum surface water, thereby reducing the number of anionic monomers available to partition and cause damage. Supportive skin damage assessment studies were performed. Changes in electrical conductance of human stratum corneum confirmed barrier impairment due to the emulsifiable concentrates and anionic surfactants. An alternative membrane, shed squamate skin was shown to be an unsuitable model for human skin damage assessment. To reduce human skin damage due to pesticide formulations alternative safer anionic surfactants and polyoxyethylated nonionic surfactants should be incorporated.