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2. Inherent structural descriptors via machine learning

Author

Telari, Emanuele, Tinti, Antonio, Settem, Manoj, Rees, Morgan, Hoddinott, Henry, Dearg, Malcom, von Issendorff, Bernd, Held, Georg, Slater, Thomas J. A., Palmer, Richard E., Maragliano, Luca, Ferrando, Riccardo, and Giacomello, Alberto

Subjects
Physics - Computational Physics
Abstract

Finding proper collective variables for complex systems and processes is one of the most challenging tasks in simulations, which limits the interpretation of experimental and simulated data and the application of enhanced sampling techniques. Here, we propose a machine learning approach able to distill few, physically relevant variables by associating instantaneous configurations of the system to their corresponding inherent structures as defined in liquids theory. We apply this approach to the challenging case of structural transitions in nanoclusters, managing to characterize and explore the structural complexity of an experimentally relevant system constituted by 147 gold atoms. Our inherent-structure variables are shown to be effective at computing complex free-energy landscapes, transition rates, and at describing non-equilibrium melting and freezing processes. The effectiveness of this machine learning strategy guided by the generally-applicable concept of inherent structures shows promise to devise collective variables for a vast range of systems, including liquids, glasses, and proteins.

Published
2024

4. In-Situ Single Particle Reconstruction Reveals 3D Evolution of PtNi Nanocatalysts During Heating

Author

Wang, Yi-Chi, Slater, Thomas J A, Leteba, Gerard M., Lang, Candace I, Wang, Zhong Lin, and Haigh, Sarah J

Subjects
Physics - Applied Physics, Condensed Matter - Materials Science
Abstract

Tailoring nanoparticles composition and morphology is of particular interest for improving their performance for catalysis. A challenge of this approach is that the nanoparticles optimized initial structure often changes during use. Visualizing the three dimensional (3D) structural transformation in situ is therefore critical, but often prohibitively difficult experimentally. Although electron tomography provides opportunities for 3D imaging, restrictions in the tilt range of in situ holders together with electron dose considerations limit the possibilities for in situ electron tomography studies. Here, we present an in situ 3D imaging methodology using single particle reconstruction (SPR) that allows 3D reconstruction of nanoparticles with controlled electron dose and without tilting the microscope stage. This in situ SPR methodology was employed to investigate the restructuring and elemental redistribution within a population of PtNi nanoparticles at elevated temperatures. We further examined the atomic structure of PtNi and found a heat induced transition from a disordered to an ordered phase. Changes in structure and elemental distribution were linked to a loss of catalytic activity in the oxygen reduction reaction. The in situ SPR methodology employed here could be extended to a wide range of in situ studies employing not only heating, but gaseous, aqueous or electrochemical environments to reveal in operando nanoparticle evolution in 3D.

Published
2023

7. Oleylamine aging of PtNi nanoparticles giving enhanced functionality for the oxygen reduction reaction

Author

Leteba, Gerard M, Wang, Yi-Chi, Slater, Thomas J A, Cai, Rongsheng, Byrne, Conor, Race, Christopher P, Mitchell, David R G, Levecque, Pieter B J, Young, Neil P, Walton, Alex, Kirkland, Angus I, Haigh, Sarah J, and Lang, Candace I

Subjects
Condensed Matter - Materials Science, Physics - Applied Physics
Abstract

We report a rapid solution-phase strategy to synthesize alloyed PtNi nanoparticles which demonstrate outstanding functionality for the oxygen reduction reaction (ORR). This one-pot co-reduction colloidal synthesis results in a monodisperse population of single-crystal nanoparticles of rhombic dodecahedral morphology, with Pt enriched edges and compositions close to Pt1Ni2. We use nanoscale 3D compositional analysis to reveal for the first time that oleylamine (OAm)-aging of the rhombic dodecahedral Pt1Ni2 particles results in Ni leaching from surface facets, producing aged particles with concave faceting, an exceptionally high surface area and a composition of Pt2Ni1. We show that the modified atomic nanostructures catalytically outperform the original PtNi rhombic dodecahedral particles by more than 2-fold and also yield improved cycling durability. Their functionality for the ORR far exceeds commercially available Pt/C nanoparticle electrocatalysts, both in terms of mass-specific activities (up to a 25-fold increase) and intrinsic area-specific activities (up to a 27-fold increase)., Comment: 14 pages, 4 figures, supplementary information

Published
2021
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11. Examining the actions of insulin-like growth factor binding protein 2 in vascular biology

Author

Slater, Thomas Alexander, Wheatcroft, Stephen, Bruns, Alexander, and Kearney, Mark

Abstract

The formation of new blood vessels; physiological function of quiescent vasculature; and remodelling of vasculature after injury, is regulated by a wide variety of complex and overlapping signalling pathways. The endothelial cell monolayer, vascular smooth muscle cells and adventitial tissue which constitute blood vessels are influenced by multiple circulating and locally secreted factors, with each tissue type exerting effects on the other; especially in the context of angiogenesis and in the pathophysiological response to vascular injury. Insulin-like growth factor binding protein-2 (IGFBP-2) has been considered an important factor in tumour angiogenesis and cellular proliferation, but little is known about its effects on vascular function, vascular remodelling, and its effects on the individual cell types within the vascular environment. In this work, we describe the effects of IGFBP-2 on vascular physiological and pathophysiological processes. We achieved this predominantly through the use of two transgenic murine models: of conditional endothelial specific IGFBP-2 overexpression, and conditional global IGFBP-2 overexpression. We demonstrate that endothelial specific IGFBP-2 overexpression has no effect on ex vivo aortic vasomotor function, whilst global overexpression of IGFBP-2 causes significant aortic hypocontractility, but without any change in endothelium-dependent vasodilatation, and without altering nitric oxide bioavailability. No change for in vivo blood pressure was evident, with increased aortic distensibility seen with global overexpression of IGFBP-2. We also demonstrate that global overexpression of IGFBP-2 leads to reduced re-endothelialization after vascular injury, but does not affect neointimal quantity, although possible changes in neointima composition were observed. Finally, increased exposure to IGFBP-2 caused an increase in sprouting angiogenesis across multiple endothelial cell types. In conclusion, increased expression of IGFBP-2 may exert multiple effects on murine vasculature in the setting of vascular vasomotor function, vascular injury and angiogenesis. More work is required to further understand the effects IGFBP-2 exerts in vascular biology, and the signalling mechanisms through which these occur.

Published
2022

13. Design-controlled Synthesis of IrO$_2$ sub-monolayers on Au Nanodendrites: Marrying Plasmonic and Electrocatalytic Properties

Author

de Freitas, Isabel C., Parreira, Luanna S., Barbosa, Eduardo C. M., Novaes, Barbara A., Mou, Tong, Alves, Tiago. V., Quiroz, Jhon, Wang, Yi-Chi, Slater, Thomas J, Thomas, Andrew, Wang, Bin, Haigh, Sarah J, and Camargoa, Pedro H. C.

Subjects
Physics - Applied Physics, Condensed Matter - Materials Science
Abstract

We develop herein plasmonic-catalytic Au-IrO$_2$ nanostructures with a morphology optimized for efficient light harvesting and catalytic surface area; the nanoparticles have a dendritic morphology, with closely spaced Au branches all partially covered by an ultrathin (1 nm) IrO$_2$ shell. This nanoparticle architecture optimizes optical features due to the interactions of closely spaced plasmonic branches forming electromagnetic hot spots, and the ultra-thin IrO$_2$ layer maximizes efficient use of this expensive catalyst. This concept was evaluated towards the enhancement of the electrocatalytic performances towards the oxygen evolution reaction (OER) as a model transformation. The OER can play a central role in meeting future energy demands but the performance of conventional electrocatalysts in this reaction is limited by the sluggish OER kinetics. We demonstrate an improvement of the OER performance for one of the most active OER catalysts, IrO$_2$, by harvesting plasmonic effects from visible light illumination in multimetallic nanoparticles. We find that the OER activity for the Au-IrO$_2$ nanodendrites can be improved under LSPR excitation, matching best properties reported in the literature. Our simulations and electrocatalytic data demonstrate that the enhancement in OER activities can be attributed to an electronic interaction between Au and IrO$_2$ and to the activation of Ir-O bonds by LSPR excited hot holes, leading to a change in the reaction mechanism (rate-determinant step) under visible light illumination., Comment: 5 figures

Published
2020

16. Mapping ice sheet elevation and elevation change using CryoSat-2 radar altimetry

Author

Slater, Thomas, Shepherd, Andrew, and McMillan, Malcolm

Subjects
551.31
Abstract

In this thesis I develop novel methods and datasets, based on the processing of CryoSat-2 satellite radar altimeter data, to improve the understanding of retrieving measurements of surface elevation and elevation change over the Antarctic and Greenland ice sheets. First, I used 6 years of CryoSat-2 altimetry to create a model of the surface height of the Antarctic Ice Sheet and ice shelves. Posted at a resolution of 1 km, 94 % of the grounded ice sheet and 98 % of the floating ice shelves are observed, and the remaining grid cells North of 88 ° S are interpolated using ordinary kriging. Taking into account slope-dependent errors and the distribution of slopes across the ice sheet, I estimated the average accuracy of the DEM to be 9.5 m - a value that is comparable to, or better than that of other models derived from satellite radar and laser altimetry. Next, I developed a new technique to retrieve estimates of the depth distribution of radar backscatter from CryoSat-2 altimeter waveforms using a backscatter model. I then applied this model to chart spatial and temporal variatibility in radar backscatter and, for the first time, explicitly estimate radar penetration depth across the interior of the Greenland Ice Sheet. I then used this information to correct for artefacts in elevation trends derived from Cryosat-2 pulse-limited altimetry resulting from an episodic melt event which reset the radar scattering horizon. Incorporating the penetration depth into the surface height retrieval, I find improved agreement when compared to independent airborne laser altimeter data recorded over the same time period. Finally, I used CryoSat-2 altimetry to estimate seasonal elevation changes in the Greenland Ice Sheet. Using regional climate model simulations of height fluctuations due to surface process alone, I demonstrate that CryoSat-2 observations track elevation changes driven by melting and snowfall accumulation in the ice sheet ablation zone. I then mapped spatial and temporal variations in seasonal elevation change, demonstrating the ability of CryoSat-2 to monitor changes in Greenland which arise due to its meteorology.

Published
2019

22. Home Education for Children with Additional Learning Needs -- A Better Choice or the Only Option?

Author

Maxwell, Nina, Doughty, Julie, Slater, Thomas, Forrester, Donald, and Rhodes, Kathyrn

Abstract

This paper presents findings from a study undertaken in Wales on the safeguarding of children educated at home. Findings revealed that just under a third of home educators had children with additional learning needs who were removed from school due to what parents reported as negative experiences. These experiences included the suitability of a school system based upon assessment and attainment for children with additional learning needs and a failure to provide adequate support. The decision to home educate was not taken lightly, with parents persevering in attempts to make school work for their children. Similar issues are identified in recent media coverage in England and Wales which has suggested that rises in home education may be due to parents "off-rolling" their children because they feel forced out of schools that are unable or unwilling to promote inclusive practices. Findings showed that it was not school-based education that was rejected intrinsically, but rather the extent to which schools could meet their child's needs. In the advent of the Additional Learning Needs and Education Tribunal (Wales) Act 2018, these findings suggest that a more nuanced understanding of education is required where home education, either full-time or combined with school attendance, may be in the best interests of the child.

Published
2020
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24. Ultralow Catalytic Loading for Optimised Electrocatalytic Performance of AuPt Nanoparticles to Produce Hydrogen and Ammonia

Author

Bezerra, Leticia S., primary, Brasseur, Paul, additional, Sullivan–Allsop, Sam, additional, Cai, Rongsheng, additional, da Silva, Kaline N., additional, Wang, Shiqi, additional, Singh, Harishchandra, additional, Yadav, Ashok K., additional, Santos, Hugo L. S., additional, Chundak, Mykhailo, additional, Abdelsalam, Ibrahim, additional, Heczko, Vilma J., additional, Sitta, Elton, additional, Ritala, Mikko, additional, Huo, Wenyi, additional, Slater, Thomas J. A., additional, Haigh, Sarah J., additional, and Camargo, Pedro, additional

Published
2024
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25. Diabetes mellitus does not alter mortality or hospitalisation risk in patients with newly diagnosed heart failure with preserved ejection fraction: Time to rethink pathophysiological models of disease progression

Author

Gierula, John, primary, Straw, Sam, additional, Cole, Charlotte A, additional, Lowry, Judith E, additional, Paton, Maria F, additional, McGinlay, Melanie, additional, Witte, Klaus K, additional, Grant, Peter J, additional, Wheatcroft, Stephen B, additional, Drozd, Michael, additional, Slater, Thomas A, additional, Cubbon, Richard M, additional, and Kearney, Mark T, additional

Published
2024
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28. Altimetry for the future: Building on 25 years of progress

Author

Abdalla, Saleh, Abdeh Kolahchi, Abdolnabi, Ablain, Michaël, Adusumilli, Susheel, Aich Bhowmick, Suchandra, Alou-Font, Eva, Amarouche, Laiba, Andersen, Ole Baltazar, Antich, Helena, Aouf, Lotfi, Arbic, Brian, Armitage, Thomas, Arnault, Sabine, Artana, Camila, Aulicino, Giuseppe, Ayoub, Nadia, Badulin, Sergei, Baker, Steven, Banks, Chris, Bao, Lifeng, Barbetta, Silvia, Barceló-Llull, Bàrbara, Barlier, François, Basu, Sujit, Bauer-Gottwein, Peter, Becker, Matthias, Beckley, Brian, Bellefond, Nicole, Belonenko, Tatyana, Benkiran, Mounir, Benkouider, Touati, Bennartz, Ralf, Benveniste, Jérôme, Bercher, Nicolas, Berge-Nguyen, Muriel, Bettencourt, Joao, Blarel, Fabien, Blazquez, Alejandro, Blumstein, Denis, Bonnefond, Pascal, Borde, Franck, Bouffard, Jérôme, Boy, François, Boy, Jean-Paul, Brachet, Cédric, Brasseur, Pierre, Braun, Alexander, Brocca, Luca, Brockley, David, Brodeau, Laurent, Brown, Shannon, Bruinsma, Sean, Bulczak, Anna, Buzzard, Sammie, Cahill, Madeleine, Calmant, Stéphane, Calzas, Michel, Camici, Stefania, Cancet, Mathilde, Capdeville, Hugues, Carabajal, Claudia Cristina, Carrere, Loren, Cazenave, Anny, Chassignet, Eric P., Chauhan, Prakash, Cherchali, Selma, Chereskin, Teresa, Cheymol, Cecile, Ciani, Daniele, Cipollini, Paolo, Cirillo, Francesca, Cosme, Emmanuel, Coss, Steve, Cotroneo, Yuri, Cotton, David, Couhert, Alexandre, Coutin-Faye, Sophie, Crétaux, Jean-François, Cyr, Frederic, d’Ovidio, Francesco, Darrozes, José, David, Cedric, Dayoub, Nadim, De Staerke, Danielle, Deng, Xiaoli, Desai, Shailen, Desjonqueres, Jean-Damien, Dettmering, Denise, Di Bella, Alessandro, Díaz-Barroso, Lara, Dibarboure, Gerald, Dieng, Habib Boubacar, Dinardo, Salvatore, Dobslaw, Henryk, Dodet, Guillaume, Doglioli, Andrea, Domeneghetti, Alessio, Donahue, David, Dong, Shenfu, Donlon, Craig, Dorandeu, Joël, Drezen, Christine, Drinkwater, Mark, Du Penhoat, Yves, Dushaw, Brian, Egido, Alejandro, Erofeeva, Svetlana, Escudier, Philippe, Esselborn, Saskia, Exertier, Pierre, Fablet, Ronan, Falco, Cédric, Farrell, Sinead Louise, Faugere, Yannice, Femenias, Pierre, Fenoglio, Luciana, Fernandes, Joana, Fernández, Juan Gabriel, Ferrage, Pascale, Ferrari, Ramiro, Fichen, Lionel, Filippucci, Paolo, Flampouris, Stylianos, Fleury, Sara, Fornari, Marco, Forsberg, Rene, Frappart, Frédéric, Frery, Marie-laure, Garcia, Pablo, Garcia-Mondejar, Albert, Gaudelli, Julia, Gaultier, Lucile, Getirana, Augusto, Gibert, Ferran, Gil, Artur, Gilbert, Lin, Gille, Sarah, Giulicchi, Luisella, Gómez-Enri, Jesús, Gómez-Navarro, Laura, Gommenginger, Christine, Gourdeau, Lionel, Griffin, David, Groh, Andreas, Guerin, Alexandre, Guerrero, Raul, Guinle, Thierry, Gupta, Praveen, Gutknecht, Benjamin D., Hamon, Mathieu, Han, Guoqi, Hauser, Danièle, Helm, Veit, Hendricks, Stefan, Hernandez, Fabrice, Hogg, Anna, Horwath, Martin, Idžanović, Martina, Janssen, Peter, Jeansou, Eric, Jia, Yongjun, Jia, Yuanyuan, Jiang, Liguang, Johannessen, Johnny A., Kamachi, Masafumi, Karimova, Svetlana, Kelly, Kathryn, Kim, Sung Yong, King, Robert, Kittel, Cecile M.M., Klein, Patrice, Klos, Anna, Knudsen, Per, Koenig, Rolf, Kostianoy, Andrey, Kouraev, Alexei, Kumar, Raj, Labroue, Sylvie, Lago, Loreley Selene, Lambin, Juliette, Lasson, Léa, Laurain, Olivier, Laxenaire, Rémi, Lázaro, Clara, Le Gac, Sophie, Le Sommer, Julien, Le Traon, Pierre-Yves, Lebedev, Sergey, Léger, Fabien, Legresy, Benoı̂t, Lemoine, Frank, Lenain, Luc, Leuliette, Eric, Levy, Marina, Lillibridge, John, Liu, Jianqiang, Llovel, William, Lyard, Florent, Macintosh, Claire, Makhoul Varona, Eduard, Manfredi, Cécile, Marin, Frédéric, Mason, Evan, Massari, Christian, Mavrocordatos, Constantin, Maximenko, Nikolai, McMillan, Malcolm, Medina, Thierry, Melet, Angelique, Meloni, Marco, Mertikas, Stelios, Metref, Sammy, Meyssignac, Benoit, Minster, Jean-François, Moreau, Thomas, Moreira, Daniel, Morel, Yves, Morrow, Rosemary, Moyard, John, Mulet, Sandrine, Naeije, Marc, Nerem, Robert Steven, Ngodock, Hans, Nielsen, Karina, Nilsen, Jan Even Øie, Niño, Fernando, Nogueira Loddo, Carolina, Noûs, Camille, Obligis, Estelle, Otosaka, Inès, Otten, Michiel, Oztunali Ozbahceci, Berguzar, P. Raj, Roshin, Paiva, Rodrigo, Paniagua, Guillermina, Paolo, Fernando, Paris, Adrien, Pascual, Ananda, Passaro, Marcello, Paul, Stephan, Pavelsky, Tamlin, Pearson, Christopher, Penduff, Thierry, Peng, Fukai, Perosanz, Felix, Picot, Nicolas, Piras, Fanny, Poggiali, Valerio, Poirier, Étienne, Ponce de León, Sonia, Prants, Sergey, Prigent, Catherine, Provost, Christine, Pujol, M-Isabelle, Qiu, Bo, Quilfen, Yves, Rami, Ali, Raney, R. Keith, Raynal, Matthias, Remy, Elisabeth, Rémy, Frédérique, Restano, Marco, Richardson, Annie, Richardson, Donald, Ricker, Robert, Ricko, Martina, Rinne, Eero, Rose, Stine Kildegaard, Rosmorduc, Vinca, Rudenko, Sergei, Ruiz, Simón, Ryan, Barbara J., Salaün, Corinne, Sanchez-Roman, Antonio, Sandberg Sørensen, Louise, Sandwell, David, Saraceno, Martin, Scagliola, Michele, Schaeffer, Philippe, Scharffenberg, Martin G., Scharroo, Remko, Schiller, Andreas, Schneider, Raphael, Schwatke, Christian, Scozzari, Andrea, Ser-giacomi, Enrico, Seyler, Frederique, Shah, Rashmi, Sharma, Rashmi, Shaw, Andrew, Shepherd, Andrew, Shriver, Jay, Shum, C.K., Simons, Wim, Simonsen, Sebatian B., Slater, Thomas, Smith, Walter, Soares, Saulo, Sokolovskiy, Mikhail, Soudarin, Laurent, Spatar, Ciprian, Speich, Sabrina, Srinivasan, Margaret, Srokosz, Meric, Stanev, Emil, Staneva, Joanna, Steunou, Nathalie, Stroeve, Julienne, Su, Bob, Sulistioadi, Yohanes Budi, Swain, Debadatta, Sylvestre-baron, Annick, Taburet, Nicolas, Tailleux, Rémi, Takayama, Katsumi, Tapley, Byron, Tarpanelli, Angelica, Tavernier, Gilles, Testut, Laurent, Thakur, Praveen K., Thibaut, Pierre, Thompson, LuAnne, Tintoré, Joaquín, Tison, Céline, Tourain, Cédric, Tournadre, Jean, Townsend, Bill, Tran, Ngan, Trilles, Sébastien, Tsamados, Michel, Tseng, Kuo-Hsin, Ubelmann, Clément, Uebbing, Bernd, Vergara, Oscar, Verron, Jacques, Vieira, Telmo, Vignudelli, Stefano, Vinogradova Shiffer, Nadya, Visser, Pieter, Vivier, Frederic, Volkov, Denis, von Schuckmann, Karina, Vuglinskii, Valerii, Vuilleumier, Pierrik, Walter, Blake, Wang, Jida, Wang, Chao, Watson, Christopher, Wilkin, John, Willis, Josh, Wilson, Hilary, Woodworth, Philip, Yang, Kehan, Yao, Fangfang, Zaharia, Raymond, Zakharova, Elena, Zaron, Edward D., Zhang, Yongsheng, Zhao, Zhongxiang, Zinchenko, Vadim, and Zlotnicki, Victor

Published
2021
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29. Au@AuPd Core-Alloyed Shell Nanoparticles for Enhanced Electrocatalytic Activity and Selectivity under Visible Light Excitation

Author

da Silva, Kaline N., Shetty, Shwetha, Sullivan−Allsop, Sam, Cai, Rongsheng, Wang, Shiqi, Quiroz, Jhon, Chundak, Mykhailo, dos Santos, Hugo L. S., Abdelsalam, IbrahiM, Oropeza, Freddy E., de la Peña O’Shea, Víctor A., Heikkinen, Niko, Sitta, Elton, Alves, Tiago V., Ritala, Mikko, Huo, Wenyi, Slater, Thomas J. A., Haigh, Sarah J., and Camargo, Pedro H. C.

Abstract

Plasmonic catalysis has been employed to enhance molecular transformations under visible light excitation, leveraging the localized surface plasmon resonance (LSPR) in plasmonic nanoparticles. While plasmonic catalysis has been employed for accelerating reaction rates, achieving control over the reaction selectivity has remained a challenge. In addition, the incorporation of catalytic components into traditional plasmonic-catalytic antenna-reactor nanoparticles often leads to a decrease in optical absorption. To address these issues, this study focuses on the synthesis of bimetallic core@shell Au@AuPd nanoparticles (NPs) with ultralow loadings of palladium (Pd) into gold (Au) NPs. The goal is to achieve NPs with an Au core and a dilute alloyed shell containing both Au and Pd, with a low Pd content of around 10 atom %. By employing the (photo)electrocatalytic nitrite reduction reaction (NO2RR) as a model transformation, experimental and theoretical analyses show that this design enables enhanced catalytic activity and selectivity under visible light illumination. We found that the optimized Pd distribution in the alloyed shell allowed for stronger interaction with key adsorbed species, leading to improved catalytic activity and selectivity, both under no illumination and under visible light excitation conditions. The findings provide valuable insights for the rational design of antenna-reactor plasmonic-catalytic NPs with controlled activities and selectivity under visible light irradiation, addressing critical challenges to enable sustainable molecular transformations.

Published
2024
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30. Bridging imaging users to imaging analysis – A community survey.

Author

Sivagurunathan, Suganya, Marcotti, Stefania, Nelson, Carl J, Jones, Martin L, Barry, David J, Slater, Thomas J A, Eliceiri, Kevin W, and Cimini, Beth A

Abstract

The 'Bridging Imaging Users to Imaging Analysis' survey was conducted in 2022 by the Center for Open Bioimage Analysis (COBA), BioImaging North America (BINA) and the Royal Microscopical Society Data Analysis in Imaging Section (RMS DAIM) to understand the needs of the imaging community. Through multichoice and open‐ended questions, the survey inquired about demographics, image analysis experiences, future needs and suggestions on the role of tool developers and users. Participants of the survey were from diverse roles and domains of the life and physical sciences. To our knowledge, this is the first attempt to survey cross‐community to bridge knowledge gaps between physical and life sciences imaging. Survey results indicate that respondents' overarching needs are documentation, detailed tutorials on the usage of image analysis tools, user‐friendly intuitive software, and better solutions for segmentation, ideally in a format tailored to their specific use cases. The tool creators suggested the users familiarise themselves with the fundamentals of image analysis, provide constant feedback and report the issues faced during image analysis while the users would like more documentation and an emphasis on tool friendliness. Regardless of the computational experience, there is a strong preference for 'written tutorials' to acquire knowledge on image analysis. We also observed that the interest in having 'office hours' to get an expert opinion on their image analysis methods has increased over the years. The results also showed less‐than‐expected usage of online discussion forums in the imaging community for solving image analysis problems. Surprisingly, we also observed a decreased interest among the survey respondents in deep/machine learning despite the increasing adoption of artificial intelligence in biology. In addition, the community suggests the need for a common repository for the available image analysis tools and their applications. The opinions and suggestions of the community, released here in full, will help the image analysis tool creation and education communities to design and deliver the resources accordingly. [ABSTRACT FROM AUTHOR]

Published
2024
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36. Co2 Hydrogenation on Pdga and Pdin Intermetallic Alloy Catalysts

Author

Bowker, Michael, primary, Lawes, Naomi, additional, Dummer, Nicholas F., additional, Fagan, Samantha, additional, Wielgosz, Oskar, additional, Gow, Isla E., additional, Smith, Louise R., additional, Slater, Thomas J. A., additional, Davies, Thomas E., additional, Aggett, Kieran J., additional, Morgan, David J., additional, Taylor, Stuart H., additional, and Hutchings, Graham J., additional

Published
2024
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37. Three dimensional chemical analysis of nanoparticles using energy dispersive X-ray spectroscopy

Author

Slater, Thomas Jack Alfred

Subjects
543, Electron tomography, Scanning transmission electron microscope, Energy dispersive X-ray spectroscopy, Bimetallic nanoparticles
Abstract

The aim of this thesis is to investigate the methodology of three dimensional chemical imaging of nanoparticles through the use of scanning transmission electron microscope (STEM) – energy dispersive X-ray (EDX) spectroscopy. In this thesis, an absorption correction factor is derived for spherical nanoparticles that can correct X-ray absorption effects. Quantification of EDX spectra of nanoparticles usually neglects X-ray absorption within the nanoparticle but may lead to erroneous results, thus an absorption correction is important for accurate compositional quantification. The absorption correction presented is verified through comparison with experimental data of Au X-ray peaks in spherical Au nanoparticles and is found to agree excellently. This absorption correction allows accurate compositional quantification of large ( > 100 nm) particles with STEM-EDX.Three dimensional chemical mapping is achievable through the use of EDX spectroscopy with electron tomography. Here, the methodology of STEM-EDX tomography is fully explored, with a focus on how to avoid artefacts introduced through detector shadowing and low counts per pixel. A varied-time acquisition scheme is proposed to correct for detector shadowing that is shown to provide a more constant intensity over a series of projections, allowing a higher fidelity reconstruction. The STEM-EDX tomography methodology presented is applied to the study of AgAu nanoparticles synthesized by the galvanic replacement reaction. The elemental distribution as a function of the composition of the as-synthesized nanoparticles is characterised and a reversal in the element segregated to the surface of the nanoparticles is found. The composition at which the reversal takes place is shown to correlate with a peak in the catalytic yield of a three component coupling reaction. It is hypothesized that a continuous Au surface results in the optimum catalytic conditions for the reaction studied, which guides the use of galvanically prepared AgAu nanoparticles as catalysts.

Published
2015

46. Exploring the role of social workers in suicide prevention

Author

Slater, Thomas

Subjects
362.28, H Social Sciences (General)
Abstract

This thesis explores the role of social workers in suicide prevention. Using a mixed methods approach the research examines how social workers understand, and work with, suicidal individuals in multi-agency and interdisciplinary settings. In my first empirical chapter (chapter five) a secondary analysis of the Adult Psychiatric Morbidity Survey (2007) (n=7,403) explores the circumstances under which social workers come into contact with suicidal individuals. Using a multinomial logistic regression it has been possible to establish that substance misuse is associated with social worker contact. This suggests that social workers are having contact with a group at elevated risk of suicide. The second part of the thesis is based on a series of semi-structured interviews with statutory social workers (n=17) (chapters six and seven), service users with a history of suicide attempts (n=3) and Community Psychiatric Nurses (CPNs) (n=3) (chapter eight). A thematic analysis of the interviews found that although statutory social workers had little or no training in assessing suicide, both service users and CPNs believed that social workers have a vital role in supporting suicidal individuals. Social workers found peer learning to be important as both a source of knowledge and learning, and as a support network. The findings of this research indicate that social workers have particular expertise in taking a holistic approach to suicide assessment and prevention. The Approved Mental Health Professional (AMHP) role is also felt to give social workers a strong knowledge of the legal issues that underpin working with this vulnerable group. However further research into the contact between social workers and suicidal service users and the assessment of suicide is necessary. The findings of this thesis have implications for practitioners, policy makers and researchers.

Published
2014

47. Zn Loading Effects on the Selectivity of PdZn Catalysts for CO2 Hydrogenation to Methanol.

Author

Lawes, Naomi, Aggett, Kieran J., Smith, Louise R., Slater, Thomas J. A., Dearg, Malcolm, Morgan, David J., Dummer, Nicholas F., Taylor, Stuart H., Hutchings, Graham J., and Bowker, Michael

Subjects
CATALYST selectivity, SCANNING transmission electron microscopy, X-ray photoelectron spectroscopy, HYDROGENATION
Abstract

PdZn/TiO2 catalysts have been investigated for the hydrogenation of CO2 to methanol. Varying the ratio of Pd and Zn using TiO2 as a support has a dramatic effect on catalytic performance. Chemical vapour impregnation was used to produce PdZn alloys on TiO2 and X-ray diffraction, X-ray photoelectron spectroscopy, and scanning transmission electron microscopy revealed changes in the structure at varying total PdZn molar ratios. Compared to monometallic Pd/TiO2, introducing a low loading of Zn drastically changes product selectivity. When Pd is alloyed with Zn above a total Zn/Pd = 1 molar ratio, methanol selectivity is improved. Therefore, for enhanced methanol productivity, it is crucial for the Zn loading to be higher than that required for the stoichiometric formation of the 1:1 β-PdZn alloy. [ABSTRACT FROM AUTHOR]

Published
2024
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