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27 results on '"Stewart, Gregor"'

4. Air pollution, traffic noise, mental health, and cognitive development: A multi-exposure longitudinal study of London adolescents in the SCAMP cohort

Author

Thompson, Rhiannon, Stewart, Gregor, Vu, Tuan, Jephcote, Calvin, Lim, Shanon, Barratt, Benjamin, Smith, Rachel B., Karim, Yasmin Bou, Mussa, Aamirah, Mudway, Ian, Fisher, Helen L., Dumontheil, Iroise, Thomas, Michael S.C., Gulliver, John, Beevers, Sean, Kelly, Frank J., and Toledano, Mireille B.

Published
2024
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16. Eddy covariance measurements highlight sources of nitrogen oxide emissions missing from inventories for central London

Author

Drysdale, Will S., primary, Vaughan, Adam R., additional, Squires, Freya A., additional, Cliff, Sam J., additional, Metzger, Stefan, additional, Durden, David, additional, Pingintha-Durden, Natchaya, additional, Helfter, Carole, additional, Nemitz, Eiko, additional, Grimmond, C. Sue B., additional, Barlow, Janet, additional, Beevers, Sean, additional, Stewart, Gregor, additional, Dajnak, David, additional, Purvis, Ruth M., additional, and Lee, James D., additional

Published
2022
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17. Eddy covariance measurements highlight sources of nitrogen oxide emissions missing from inventories for central London

Author

Drysdale, Will S., Vaughan, Adam R., Squires, Freya A., Cliff, Sam J., Metzger, Stefan, Durden, David, Pingintha-Durden, Natchaya, Helfter, Carole, Nemitz, Eiko, Grimmond, C. Sue B., Barlow, Janet, Beevers, Sean, Stewart, Gregor, Dajnak, David, Purvis, Ruth M., Lee, James D., Drysdale, Will S., Vaughan, Adam R., Squires, Freya A., Cliff, Sam J., Metzger, Stefan, Durden, David, Pingintha-Durden, Natchaya, Helfter, Carole, Nemitz, Eiko, Grimmond, C. Sue B., Barlow, Janet, Beevers, Sean, Stewart, Gregor, Dajnak, David, Purvis, Ruth M., and Lee, James D.

Abstract

During March–June 2017 emissions of nitrogen oxides were measured via eddy covariance at the British Telecom Tower in central London, UK. Through the use of a footprint model the expected emissions were simulated from the spatially resolved National Atmospheric Emissions Inventory for 2017 and compared with the measured emissions. These simulated emissions were shown to underestimate measured emissions during the daytime by a factor of 1.48, but they agreed well overnight. Furthermore, underestimations were spatially mapped, and the areas around the measurement site responsible for differences in measured and simulated emissions were inferred. It was observed that areas of higher traffic, such as major roads near national rail stations, showed the greatest underestimation by the simulated emissions. These discrepancies are partially attributed to a combination of the inventory not fully capturing traffic conditions in central London and both the spatial and temporal resolution of the inventory not fully describing the high heterogeneity of the urban centre. Understanding of this underestimation may be further improved with longer measurement time series to better understand temporal variation and improved temporal scaling factors to better simulate sub-annual emissions.

Published
2022

20. The expression of pea (Pisum sativum) vicilin in the yeast, Saccharomyces cerevisiae

Author

Stewart, Gregor James

Subjects
572, Pea seed protein vicilin
Abstract

This study has demonstrated and investigated the expression of a cDNA, coding for the pea seed storage protein vicilin, in the yeast, Saccharomyces cerevisiae. The cDNA was contained in the plasmid pLG1.63 and has been characterised and sequenced. The sequence showed that the cDNA coded for a 47KDa type of vicilin with a putative 24 amino-acid signal peptide, a proteolytic cleavage site and one glycosylation signal. The cDNA was cloned into two yeast expression vectors. The first utilised the GALIO promoter rendering expression of the cDNA inducible galactose, the construct was called pDUB2300. The second construct, pDUB2302, placed the cDNA under the control of the PGK promoter, rendering the cDNA constitutively expressed. When transformed into yeast, both constructs produced an immunoreactive vicilin species of M(_r) =49KDa. In the case of pDUB2302 the protein was produced at up to 5.5% of total cell protein. The protein was shown to be associated with a particulate fraction and displayed altered precipitation characteristics when compared with pea vicilin. By using tunicanydn and N-glycosidase, the protein was shown to be unglycosylated. Partial purification and (^35)S-methionine labelling demonstrated that the signal pep tide remained uncleaved. Cell fractionation studies indicated that vicilin was enriched in the yeast microsomal fraction, suggesting that vicilin was located in the EH. This was confirmed electron microscopy of immuno-gold labelled yeast which showed vicilin associated with the ER. The electron micrographs also suggested that a small proportion of the protein might be reaching thecolgi apparatus and the vacuole membrane. The presence of specific cleavage products on some western blots suggested that vicilin possessed a cleavage site for a yeast protease, though whether this was the same site as the pea proteolytic cleavage site was not determined. The pattern and nature of the expression of vicilin from this cDNA was discussed in the context of heterologous protein expression in yeast in general and plant storage protein expression in yeast in particular.

Published
1989

21. Traffic management strategies for emissions reduction: recent experience in London

Author

Beevers, Sean, Carslaw,David, Williams,Martin, Dajnak,David, Stewart,Gregor, Kelly,Frank, and Fussell,Julia

Subjects
Energy and Emission Control Technologies
Abstract

Sean David Beevers, David Carlin Carslaw, David Dajnak, Gregor B Stewart, Martin Lloyd Williams, Julia C Fussell, Frank James Kelly MRC-PHE Centre for Environment and Health, Facility of Life Sciences and Medicine, King’s College, London, UK Abstract: Air pollution strategies in London over the last 12 years have centered upon the congestion charging scheme, and at the same time, the fitting of particle traps to London buses, the low emissions zone (LEZ), and the Mayor’s Air Quality Strategy (MAQS). The 2003 congestion charging scheme achieved much of the scheme’s aims, but the demand to travel and the need for road space eroded the initial benefits. While fitting particle traps on buses was predicted to reduce particulate matter (PM) exhaust emissions, the introduction of phases 1 and 2 of the LEZ and MAQS strategies were both predicted to have modest emission impacts. Reliance on new Euro-standard vehicles to reduce emissions, and as a way of designing LEZs, has been problematic, with oxides of nitrogen (NOx) and nitrogen dioxide (NO2) emissions from diesel vehicles reducing less than predicted. Consequently, the UK has not met annual NO2 European Union (EU) limit values, necessitating a time extension application. A mismatch between PM10 ambient trends and emissions has also been reported, with the long-term performance of PM particle filters remaining an important question. Assessing London’s traffic management schemes has relied upon emission inventories and dispersion models, and to date, there has been no confirmation of the effects of the schemes using ambient data, a challenging and important area of research. However, measurements of ambient NOx, NO2, ozone, PM species, and roadside vehicle emissions have all contributed to the improvement of road traffic emission inventories in London, and it remains important to undertake ambient monitoring to assess future schemes. Looking forward, the real-world emissions performance of Euro 6/VI vehicles, selective catalytic reduction, and the ultra-low emissions zone in London will play a critical role in meeting EU limit values for ambient NO2, and in light of the increasing health evidence of urban air pollution, policy makers should aim to reduce PM concentrations toward health-based World Health Organization guideline values. Keywords: congestion charging, low emissions zone, traffic management, NOx, PM10 vehicle emissions

Published
2016

22. Abatement of an Aircraft Exhaust Plume Using Aerodynamic Baffles

Author

Bennett, Michael, primary, Christie, Simon M., additional, Graham, Angus, additional, Garry, Kevin P., additional, Velikov, Stefan, additional, Poll, D. Ian, additional, Smith, Malcolm G., additional, Mead, M. Iqbal, additional, Popoola, Olalekan A. M., additional, Stewart, Gregor B., additional, and Jones, Roderic L., additional

Published
2013
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24. Developmental expression of the murineMopb gene

Author

Montague, Paul, primary, Dickinson, Peter J., additional, McCallion, Andrew S., additional, Stewart, Gregor J., additional, Savioz, Armand, additional, Davies, R. Wayne, additional, Kennedy, Peter G.E., additional, and Griffiths, Ian R., additional

Published
1997
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27. Climate change policies reduce air pollution and increase physical activity: Benefits, costs, inequalities, and indoor exposures.

Author

Beevers S, Assareh N, Beddows A, Stewart G, Holland M, Fecht D, Liu Y, Goodman A, Walton H, Brand C, Evangelopoulos D, Wood D, Vu T, and Dajnak D

Abstract

The burden of diseases attributable to air pollution is comparable to those of global health risks such as unhealthy diets and tobacco smoking, with many air pollution sources also emitting climate heating gases. In this UK study we estimated the co-benefits of Net Zero (NZ) climate policy on the health benefits of air pollution reduction, increased active travel, outdoor exposure inequalities and indoor air pollution changes. The study focused on two of the largest UK sources, road transport and building heating, with comparisons made between NZ and UK existing policy, referred to as Business as Usual (BAU). Particulate matter (PM 2.5 ), Nitrogen Dioxide (NO 2 ) and Ozone (O 3 ) projections were made between 2019 and 2050, with emphasis placed upon the NZ co-benefits in 2030 and 2040. We compared the UK BAU scenarios with the Climate Change Committee's (CCC) Balanced Net Zero Pathway (BNZP) and Widespread Innovation (WI) pathway. Compared to BAU predictions, BNZP assumptions lead to more electric vehicles, reduced vehicle km, more low carbon building heating, and reduced emissions of NO 2 and PM 2.5 . By 2040 under BNZP, relative to BAU, the buildings sector was predicted to be three times more effective at reducing PM 2.5 than road transport. To help reduce the inequality gap the NZ building transition was tailored toward those most in need. Outdoor air pollution exposure inequalities prevailed across the socioeconomic spectrum, especially for NO 2 , but were less pronounced due in part to NZ policies. Core air quality health benefits for the BNZP buildings sector were £21.3 billion (16.4 to 26.2) by 2050 and £98.4 billion (75.7 to 121.1) by 2154. For the transport sector the health benefits were £9.1 billion (7.0 to 11.2) by 2050 and £36.5 billion (28.1 to 44.9) by 2154. NZ building sector operating costs did not achieve break-even via efficiency savings, but with Greenhouse Gas (GHG) (lower benefits) break-even was achieved in 2052. With additional air pollution health benefits, building-sector time to break-even improved by between 3.1 (2.5 to 4.7) and 6.3 (4.7 to 7.6) years to between 2046 and 2049. Analysis found that removing gas cooking at home, for NZ, may result in greater concentration reductions than outdoor air pollution for NO 2 . Net Zero health and economic co-benefits are large, as are the changes needed, requiring political leadership and public engagement. Our findings are relevant to other countries facing the NZ transition., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Published
2024
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