RSS 1.0Welcome to ChesterRep - the University of Chester's Online Research Repository
ChesterRep is the University of Chester's institutional repository and an online platform designed to collate, store, and aid discoverability of the University’s research.
All University of Chester staff are expected to use the Current Research Information System, Symplectic Elements, to submit material to ChesterRep. Guidance on how to deposit and manage publications using Elements can be found here. You can also discover more about our editorial and open access policies here. Please note that you must be a member of the University to view these pages.
If you are a student at the University of Chester and want to submit work to ChesterRep, please contact researchsupport.lis@chester.ac.uk.
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Parametric optimisation of resistance welding thermoplastics-based composites via computational and experimental approachesIn this study, the resistance welding process for carbon fibre reinforced thermoplastic composites (FRTPC) has been parametrically investigated through simulation and experiment processes. Heat transfer of resistance welding was studied computationally to generate optimum welding parameters. By applying a transient three-dimensional heat transfer model on COMSOL Multiphysics, evolution of temperature in the joint during welding process was simulated with various combinations of power densities and clamping distances. From different combinations of parameters, two main characteristics of heat transfer were revealed, which consequently resulted in various melting degree, uniformity of temperature upon welding interface, and heat penetrating through laminates in thickness direction. Based on optimum parameters, experimental welding tests were conducted, and mechanical tests showed that lap shear strength is proportional to melting degree but is independent of thermal penetration.
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Comparative study of hypertension, diabetes, dementia and smoking in military veterans and non-veterans: a quantitative study using primary healthcare dataIntroduction: Primary healthcare (PHC) patient medical records contain Systematised Nomenclature of Medicine-Clinical Terms (SNOMED-CT) that include information regarding diagnosis, demographics and veterans’ status. This study intended to identify, analyse and compare the prevalence of type 2 diabetes, hypertension, dementia and smoking tobacco in veterans and non-veterans, including stratification by age and gender. Methods: The authors partnered with 13 PHC practices with a population of 137 410 patients. Staff extracted matched veteran and non-veteran SNOMED-CT data from patient medical records; then sent the authors anonymised data in an amalgamated format between October 2023 and January 2024. Patients were from a local community and therefore social and environmental factors would be similar. Submitted information was inputted into an SPSS database 28 for analysis which included descriptive and inferential statistics to indicate statistical significance. Results: In total, 5458 PHC electronic records were examined comprising 2729 veterans and 2729 demographically matched for age and gender non-veterans. Each group contained 86.4% (N=2359) men and 13.6% (N=370) women. The mean age was 63.8 years (SD 17.7). Rates of hypertension were 20.9% in veterans compared with 17.6% in non-veterans (p=0.002). Type 2 diabetes mellitus was 8.3% in veterans compared with 6.4% in non-veterans (p=0.007). Dementia was 2.1% of veterans compared with 2.5% of non-veterans (p=0.32). Smoking was 11.8% of veterans compared with 10.6% of non-veterans (p=0.16). Conclusion: These results reveal that veterans were statistically more likely to be diagnosed with hypertension and diabetes. This study should assist in a better understanding of the healthcare needs of the veteran population to potentially inform better patient-centred care. However, the effectiveness of using PHC patient medical records requires increased efforts to improve data quality which needs improved PHC staff knowledge, consistency in SNOMED-CT coding, better veteran medical e-record registration and coding and better data transmission between the Defence Medical Services and PHC.
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The thermal physiology of Lysathia sp. (Coleoptera: Chrysomelidae), a biocontrol agent of parrot’s feather in South Africa, supports its successThe establishment success of biocontrol agents originating from tropical regions is often limited by climate when introduced in temperate regions. However, the flea beetle, Lysathia sp. (Coleoptera: Chrysomelidae), a biocontrol agent of Myriophyllum aquaticum (Vell.) Verdc. (Haloragaceae) in South Africa, is an effective agent in regions where other biocontrol agents of tropical aquatic weeds have failed due to winter-induced mortality. The development (degree-day model) and thermal tolerance (critical thermal minimum/maximum [CTmin/max] and lower/upper lethal limits [LLT/ULT50]) of Lysathia sp. were investigated to explain this success. The model predicted that Lysathia sp. could complete 6 to 12 generations per year in the colder regions of the country. The lower threshold for development (t0) was 13.0 °C and thermal constant (K) was 222.4 days, which is considerably lower than the K values of other biocontrol agents of aquatic weeds in South Africa. This suggests that above the temperature threshold, Lysathia sp. can develop faster than those other species and complete multiple life cycles in the cooler winter months, allowing for rapid population growth and thus improving M. aquaticum control. Furthermore, the CTmin of Lysathia sp. was 2.3 ± 0.2 °C and the CTmax was 49.0 ± 0.5 °C. The LLT50 was calculated as ∼ −7.0 °C and the ULT50 as ∼ 43.0 °C. These wide tolerance ranges and survival below freezing show why Lysathia sp. has established at cool sites and suggest that it may be a suitable agent for other cold countries invaded by M. aquaticum.
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Advances in preparation of acellular human dermis for tissue banking and transplantationNon-healing wounds cost the National Health Service over £5.6 billion annually in wound management. Skin allografts are used to treat non-healing wounds, ulcers and burns, offering the best protection against infection. In order to allow host cells to repopulate and to avoid immunogenicity, cell components are removed through decellularisation. Decellularisation of human dermis has so far been performed in NHS Blood and Transplant using a combination of two enzymes (RNase T1 and the recombinant human DNase Pulmozyme)®. This study aims at validating a new method to remove DNA from donated dermis via the use of a single enzyme, Benzonase, known for its effectiveness of DNA digestion. Skin samples were decellularised by removing the epidermis, lysing of dermal cells, removal of cellular fragments by a detergent wash and removal of nucleic acids by a nuclease incubation with either Benzonase or Pulmozyme + RNase T1. DNA quantification with PicoGreen, as well as histology on wax-embedded biopsies, stained with DAPI and haemotoxylin and eosin, were performed. In vitro toxicity test on human osteosarcoma immortalised cells and skin fibroblasts, and biomechanical (tensile) testing, were also performed. The effectiveness of DNA digestion with the new methodology was comparable to previous procedure. Mean DNA removal percentage following decellularisation with Pulmozyme + RNase was 99.9% (3.83 ng/mg). Mean DNA removal percentage with Benzonase was 99.8% (9.97 ng/mg). Histology staining showed complete decellularisation following either method. Benzonase was proven to be non-toxic to both cell lines used, and a one-way Anova test showed no significant difference in neither stress nor strain between acellular dermal matrix decellularised with either Benzonase or Pulmozyme + RNase T1. Benzonase was able to effectively decellularise dermis after prior removal of epidermis. It performed just as well as the combination of Pulmozyme + RNase T1, but represents significant advantages in terms of cost effectiveness, procurement and storage; Benzonase has been successfully used in the decellularisation of other tissues, thus would be better for Tissue Banking use. Switching to this combined DNase/RNase can have far-reaching consequences in the production of acellular human dermal matrix by NHSBT and in the treatment of patients requiring it.
