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Your search keyword '"Walsh, T. R."' showing total 317 results
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317 results on '"Walsh, T. R."'

2. Antibiotic resistance genes in the gut microbiota of mothers and linked neonates with or without sepsis from low- and middle-income countries

Author

Carvalho, M. J., Sands, K., Thomson, K., Portal, E., Mathias, J., Milton, R., Gillespie, D., Dyer, C., Akpulu, C., Boostrom, I., Hogan, P., Saif, H., Ferreira, A., Nieto, M., Hender, T., Hood, K., Andrews, R., Watkins, W. J., Hassan, B., Chan, G., Bekele, D., Solomon, S., Metaferia, G., Basu, S., Naha, S., Sinha, A., Chakravorty, P., Mukherjee, S., Iregbu, K., Modibbo, F., Uwaezuoke, S., Audu, L., Edwin, C. P., Yusuf, A. H., Adeleye, A., Mukkadas, A. S., Zahra, R., Shirazi, H., Muhammad, A., Ullah, S. N., Jan, M. H., Akif, S., Mazarati, J. B., Rucogoza, A., Gaju, L., Mehtar, S., Bulabula, A. N. H., Whitelaw, A., Roberts, L., and Walsh, T. R.

Published
2022
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3. Development of a pen-side diagnostic test for liver fluke infections in cattle and sheep

Author

Walsh, T. R., Williams, Diana, and Hodgkinson, Jane

Abstract

Fasciola hepatica is a common trematode parasite of cattle and sheep worldwide. Undiagnosed infections can lead to significant production losses in ruminant livestock, or in worst cases, sudden death from extensive damage to the liver. Over recent years, prevalence of fluke has increased within the UK. This in turn has led to an increased reliance on flukicide drugs for control. Resistant fluke populations have now been reported in many areas. Diagnostic tests are crucial for control of disease. Current diagnostics include faecal egg counts, antibody ELISAs using serum or milk and copro-antigen ELISAs. These tests each have their own limitations, but for all, samples must be sent to laboratories for testing, adding time and costs to the diagnosis. A pen-side diagnostic test would be invaluable for farmers, allowing them to diagnose infections on farm and target individual treatments, avoiding the use of herd blanket treatments which can contribute to spread of resistance. In this thesis, we aim to produce a prototype penside diagnostic test. In Chapter 2, we produced a recombinant CL1 (rCL1) in the yeast Pichia pastoris intended for use in the pen-side test. Using Western blotting we showed that host antibodies from experimentally infected cattle and sheep specifically recognised fluke cathepsin enzymes, L1 (CL1) and L2. In Chapter 3, we compared the rCL1 antigen against native fluke excretory-secretory (ES) products for its ability to detect host antibodies by ELISA in naturally and experimentally infected cattle and sheep. Serum antibodies from experimentally infected animals showed strong recognition of rCL1, whilst recognition by naturally infected animals was inconsistent. This was confirmed by peptide array. In Chapter 4, we investigated the possibility that the poor antibody recognition by naturally infected animals could be due to variation in the rCL1 protein sequence compared to native CL1. We sequenced the CL1 gene from seven parasites and showed that there was variation within the CL1 gene which translated to differences in the amino acid sequence. This variation did not explain the poor host antibody recognition of our rCL1 by naturally infected animals as these changes were outside of the immunogenic areas identified in Chapter 3. The observed variation also did not result in any conformational changes to the rCL1 as determined by modelling the 3D structure of the protein. In Chapter 5 we used 2D Western blotting to show that host antibodies from naturally infected animals recognised multiple antigens within fluke ES products, and these antigens were identified through mass spectrometry. The results suggested that further considerations would be needed for preparation of the pen-side test before it could be made a commercial test. Overall, these results suggest there are differences in the host antibody response to fluke ES products between naturally and experimentally infected cattle and sheep. Whilst there is still much validation needed before the pen-side test can be made commercially available, this test has the potential for diagnosis of fluke infections on farm.

Published
2018
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4. Incidence and sociodemographic, living environment and maternal health associations with stillbirth in a tertiary healthcare setting in Kano, Northern Nigeria

Author

Milton, Rebecca, Modibbo, F., Gillespie, D., Alkali, F. I., Mukaddas, A. S., Kassim, A., Sa’ad, F. H., Tukur, F. M., Khalid, R. Y., Muhammad, M. Y., Bello, M., Edwin, C. P., Ogudo, E., Iregbu, K. C., Jones, L., Hood, K., Ghazal, P., Sanders, J., Hassan, B., Belga, F. J., and Walsh, T. R.

Published
2022
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6. Atomistic simulations of calcium aluminosilicate interfaced with liquid water.

Author

Vuković, F., Garcia, N. A., Perera, S., Turchi, M., Andersson, M. P., Solvang, M., Raiteri, P., and Walsh, T. R.

Subjects
CALCIUM, MOLECULAR dynamics, STONE, WOOL, MINERAL wool, GLASS fibers, LIQUID surfaces
Abstract

The dissolution behavior of calcium aluminosilicate based glass fibers, such as stone wool fibers, is an important consideration in mineral wool applications for both the longevity of the mineral wool products in humid environments and limiting the health impacts of released and inhaled fibers from the mineral wool product. Balancing these factors requires a molecular-level understanding of calcium aluminosilicate glass dissolution mechanisms, details that are challenging to resolve with experiment alone. Molecular dynamics simulations are a powerful tool capable of providing complementary atomistic insights regarding dissolution; however, they require force fields capable of describing not-only the calcium aluminosilicate surface structure but also the interactions relevant to dissolution phenomena. Here, a new force field capable of describing amorphous calcium aluminosilicate surfaces interfaced with liquid water is developed by fitting parameters to experimental and first principles simulation data of the relevant oxide-water interfaces, including ab initio molecular dynamics simulations performed for this work for the wüstite and periclase interfaces. Simulations of a calcium aluminosilicate surface interfaced with liquid water were used to test this new force field, suggesting moderate ingress of water into the porous glass interface. This design of the force field opens a new avenue for the further study of calcium and network-modifier dissolution phenomena in calcium aluminosilicate glasses and stone wool fibers at liquid water interfaces. [ABSTRACT FROM AUTHOR]

Published
2023
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7. The Structure of Rh$_8^+$ in the Gas Phase

Author

Harding, D. J., Walsh, T. R., Hamilton, S. M., Hopkins, W. S., Mackenzie, S. R., Gruene, P., Haertelt, M., Meijer, G., and Fielicke, A.

Subjects
Physics - Atomic and Molecular Clusters
Abstract

The geometric structure of the Rh$_8^+$ cation is investigated using a combination of far-infrared multiple photon dissociation spectroscopy and density functional theory (DFT) calculations. The energetic ordering of the different structural motifs is found to depend sensitively on the choice of pure or hybrid exchange functionals. Comparison of experimental and calculated spectra suggests the cluster to have a close-packed, bicapped octahedral structure, in contrast to recent predictions of a cubic structure for the neutral cluster. Our findings demonstrate the importance of including some exact exchange contributions in the DFT calculations, via hybrid functionals, when applied to rhodium clusters, and cast doubt on the application of pure functionals for late transition metal clusters in general., Comment: 10 pages, 3 figures

Published
2009
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9. Additional file 1 of Incidence and sociodemographic, living environment and maternal health associations with stillbirth in a tertiary healthcare setting in Kano, Northern Nigeria

Author

Milton, Rebecca, Modibbo, F., Gillespie, D., Alkali, F. I., Mukaddas, A. S., Kassim, A., Sa’ad, F. H., Tukur, F. M., Khalid, R. Y., Muhammad, M. Y., Bello, M., Edwin, C. P., Ogudo, E., Iregbu, K. C., Jones, L., Hood, K., Ghazal, P., Sanders, J., Hassan, B., Belga, F. J., and Walsh, T. R.

Abstract

Additional file 1.

Published
2022
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11. Predicted structures of calcium aluminosilicate glass as a model for stone wool fiber:effects of composition and interatomic potential

Author

Turchi, M., Perera, S., Ramsheh, S., Popel, A. J., Okhrimenko, D. V., Stipp, S. L.S., Solvang, M., Andersson, M. P., Walsh, T. R., Turchi, M., Perera, S., Ramsheh, S., Popel, A. J., Okhrimenko, D. V., Stipp, S. L.S., Solvang, M., Andersson, M. P., and Walsh, T. R.

Abstract

Characterization of compositionally-complex aluminosilicate glass particles and fibers such as stone wool, and their interfaces with water and ions, is significant to a range of areas regarding dissolution phenomena. Knowledge of atomic level structures of these interfaces is critical to elucidating their dissolution traits. Molecular simulations can provide these details, complementing experimental efforts. However, prediction of the structure of stone wool fiber has been hampered by a lack of suitable inter-atomic potentials. Here, two candidate potentials are evaluated for their ability to recover experimental structural data of calcium aluminosilicate (CaO-Al2O3-SiO2) glass of compositions relevant to stone wool fibers. Both potentials produce structures that are broadly consistent with experimental data, including defect concentrations, aluminium avoidance, and ring size distributions, and either could provide a suitable basis for modelling dissolution of these materials.

Published
2021

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