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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Effect of transforming growth factor-β2 on biological regulation of multilayer primary chondrocyte culture(2018)Cytokines are extremely potent biomolecules that regulate cellular functions and play multiple roles in initiation and inhibition of disease. These highly specialised macromolecules are actively involved in control of cellular proliferation, apoptosis, cell migration and adhesion. This work, investigates the effect of transforming growth factor-beta2 (TGF-β2) on the biological regulation of chondrocyte and the repair of a created model wound on a multilayer culture system. Also the effect of this cytokine on cell length, proliferation, and cell adhesion has been investigated. Chondrocytes isolated from knee joint of rats and cultured at 4 layers. Each layer consisted of 2 × 105 cells/ml with and without TGF-β2. The expression of mRNA and protein levels of TGF-β receptors and Smad1, 3, 4, and 7 have been analysed by RT-PCR and western blot analysis. The effect of different supplementations in chondrocyte cell proliferation, cell length, adhesion, and wound repair was statistically analysed by One-way ANOVA test. Our results showed that the TGFβ2 regulates mRNA levels of its own receptors, and of Smad3 and Smad7. Also the TGF-β2 caused an increase in chondrocyte cell length, but decreased its proliferation rate and the wound healing process. TGF-β2 also decreased cell adhesion ability to the surface of the culture flask. Since, TGF-β2 increased the cell size, but showed negative effect on cell proliferation and adhesion of CHC, the effect of manipulated TGF-β2 with other growth factors and/or proteins needs to be investigated to finalize the utilization of this growth factor and design of scaffolding in treatment of different types of arthritis.
Impact of duty cycle on wear progression in variable-displacement vane oil pumps(2018)Variable-displacement vane oil pumps are increasingly employed in automotive powertrains for their efficiency benefits through reduced losses. However, confirming long life reliability of a new commodity based on limited data available from product development tests and early field experience is a significant challenge, which is addressed by the work presented in this paper. The approach presented combines physical examination of pumps returned from tests, with analysis of damage factors for pump wear progression, and an analysis of functional parameters for the powertrain system focused on the cause effect linkages across the systems hierarchy. The metrology results from physical measurements of used parts provide useful insights for the wear progression and the expected service performance of the pump. The paper also expands towards a data driven approach based on ECU data analysis that could provide a pathway towards the development of online health monitoring and diagnostics of the oil pumps.
Dynamic modelling and operational optimisation of natural draft cooling towers(2018)Natural draft cooling towers are subjected to dynamic air temperature and humidity ratio of air throughout the day. Their performances based on steady state model is restricted to single air temperature and humidity ratio of air values and thus are not accurate. In this work, a dynamic model for a natural draft cooling tower is developed. Air temperature and relative humidity data for Johannesburg were acquired to develop dynamic correlations for these two parameters and are embedded in the process model together with the dynamic model of the collection basin of the tower. A simple algorithm is proposed to solve the resulting boundary value problem. Finally, the common perception that seawater/river water should be used instead of freshwater as cooling medium is tested via optimisation where the operating costs of the process for two cooling mediums is minimised. The freshwater has been found to be cost effective cooling medium.
Does a more dynamic method of partial weight bearing instruction translate to improved protocols?(2018)Background: Partial weight bearing protocols are commonly incorporated into rehabilitation to enhance recovery. Patients are often prescribed protocols that refer to a percentage of their body weight, such as 20% weight bearing, that should be placed through the healing limb during activities such as walking (gait). In order to achieve these partial weight baring protocols patients are usually provided with walking aids such as crutches. Accurate reproducibility of and compliance with these protocols could be considered essential to the rehabilitation process, however poor reproducibility of partial weight bearing protocols during crutch assisted gait using a current method of instruction has been shown. Aims: The aim of this study was to determine whether a more dynamic method of partial weight bearing protocol instruction, was more accurately reproduced. Methods: In total, 16 participants were randomly allocated to one of two groups and were taught 20% partial weight bearing using two different methods of instruction. A participant’s ability to reproduce their target load using crutch assisted gait was assessed using a force plate. Findings: The mean error for the static method of instruction was significantly greater than the more dynamic method. Conclusion: As seen previously, the static method of instruction of partial weight bearing protocols, using bathroom scales, does not seem to translate accurately to dynamic motion; however, the more dynamic method assessed in this study appears to result in more accurate reproducibility.
Serviceability performance of composite cellular beams with partial shear connection(2018-11)For composite cellular beams, additional deflections occur due to the loss of bending and shear stiffness at the opening positions and also due to slip in the shear connectors caused by partial shear connection. Design formulae are presented for the additional deflection of composite beams with circular openings or for cellular beams as a function of the proportionate depth of the openings. The simplified formulae are calibrated against finite element results for both cellular and solid web beams and also against measured deflections of a 15.3 m composite cellular beam test. This additional deflection is presented as a function of flexural and shear terms that are a function of the span:depth ratio. For modelling of cellular beams to determine deflections, the circular opening may be represented by an equivalent rectangular opening of length equal to 70% of the opening diameter.