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203 results on '"Skinner, Thomas A."'

1. Diagnostic uncertainty presented barriers to the timely management of acute thrombotic thrombocytopenic purpura in the United Kingdom between 2014 and 2019

Author

Bull, Tom P., McCulloch, Rory, Nicolson, Phillip L.R., Doyle, Andrew J., Shaw, Rebecca J., Langridge, Alexander, Sayar, Zara, Tucker, David L., Pettit, Michala, Perry, Rita, Thomas, William, Page, Catherine, Whalley, Ioana, Dutt, Tina, Garth, Louise, Lester, Will, Buka, Richard J., Subhan, Mary, Ware, Victoria, Rayment, Rachel, Castle, Daniel, Etherington, Astrid, Carter‐Brzezinski, Luke, Peters, Jayne, Corrigan, Claire, Sharma, Narind, Benson, Gary, Challenor, Sarah, Skinner, Thomas S., Zhao, Rui, McLeod‐Kennedy, Lyndsay A.G., Douglas, Kenneth, Knott, Amy, Smith, Sophie, Wolf, Julia, Todd, Sophie A., McDonald, Vickie, Rampotas, Alexandros, Dean, Christopher, Sangha, Gavinda, Pavord, Sue, Denny, Nicholas, Jaafar, Sarah, McLaughlin, David P.T., Ross, Jennifer E., Karanth, Mamatha, Beverstock, Sarah L., Mansonso, Lynn, Burrows, Samuel H., Tauro, Sudhir, Shenouda, Amir, Bailiff, Benjamin M., Kajita, Daniel, Hermans, Joannes, Goradia, Harshita, Finan, Emily M., Alford, Sarah, Pickard, Keir, Greystoke, Brigit, Fail, Thomas, Abdussalam, Asmaa, Roberts, Lara N, Clark, James B., Heeney, Natalie, Young, Jennifer, Maddox, Jamie, Srinath, Swathy, Khawaja, Jahanzeb, Parkes, Jayne, Babiker, Samah, Hunt, Beverley J., Wheeldon, Sarah L., Kerr, Paul, Tahhan, Molham, Vickers, Mark, Pike, Alexandra C., Hill, Quentin, Mustafa, Nadreen, Almaremi, Azza, Hughes, Emily, McGoldrick, Sean J.F., Loizou, Eleana, James, Izabela, Boyce, Sara R., Farmer, Isabel, Thanigaikumar, Murugaiyan, Wickenden, Katherine, Gooding, Richard, Thornton, Kathryn, Kane, Clare, Cole, Adam, Griffin, JessicaC, Docherty, Suzanne, Dixon, Kiri I., Crowe, Josephine, Sheridan, Mathew, De Lord, Corinne, Sud, Amit, Austin, Anna, Coooper, Nichola, Bailey, Chris, Attwell, Luke, Hall, Rachel, Gray, Benjamin, Chauhan, Salena R., Lokare, Anand, Gudger, Amy, Horgan, Claire, Venkatadasari, Indrani, Kaddam, Israa, Mapplebeck, Claire L., Van Veen, Joost, Raj, Maya, De Abrew, Kanchana, Belsham, Edward, Gyansah, Cecilia, Sadullah, Shalal, Salhan, Beena, Murrin, Richard, Williams, Rhys L., Stewart, Andrew, Cornish, Naomi, Otton, Sophie, Khan, Zeeshan, Ackroyd, Sam, Chen, Lucia Y., Lafferty, Nicholas P., Leonforte, Francesca, Pemberton, Nicholas, Rawi, Emanal, Triantafyllopoulou, Diana, Adiyodi, Jagdish, Yong, Jun, Jones, Elizabeth, Davies, David, Peck, Rachel C., Philip, Robson, Seddon, Thomas, Cahalin, Paul, Prodger, Catherine, Dutton, David A., Sternberg, Alexander J., Chengal, Rajani, Polzella, Paolo, and Scully, Marie

Published
2022
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2. A Novel Cooling Device for Kidney Transplant Surgery.

Author

Dergham, Ali, Witherspoon, Luke, Power, Liam, Nashed, Joseph Y., and Skinner, Thomas A. A.

Abstract

Background: Prolonged warm ischemia time (WIT) in kidney transplantation is associated with numerous adverse outcomes including delayed graft function and decreased patient and graft survival. Circumventing WIT lies in maintaining renal hypothermia and efficiently performing the vascular anastomosis during this portion of the procedure. Although numerous methods of intra-operative renal cooling have been proposed, most suffer from practical limitations, and none have been widely adopted. Herein we describe a novel device specifically designed to maintain renal hypothermia during kidney transplant surgery. Methods: Aluminum tubing was organized in a serpentine pattern to create a malleable, form-fitting cooling jacket to manipulate renal allografts during transplant surgery. Adult porcine kidneys were used to test the device with 4°C saline as coolant. Kidneys were placed at 24°C; surface and core temperatures were monitored using implanted thermocouples. Anastomosis of porcine kidney vessels to GORE-TEX® vascular grafts in an ex-vivo operative field was performed to assess the functionality of the device. Results: The device maintained surface and core graft temperatures of ≤5°C after 60 minutes of WIT. Furthermore, the device provided hands-free retraction and support for the allograft. We found that ex-vivo anastomosis testing was enhanced by the presence of the cooling jacket. Conclusions: This proof-of-concept study demonstrated that our novel device is a practical tool for renal transplantation and can maintain sufficiently cool graft temperatures to mitigate WIT in an ex-vivo setting. This device is the first of its kind and has the potential to improve kidney transplant outcomes by eliminating WIT during graft implantation. [ABSTRACT FROM AUTHOR]

Published
2024
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4. Two-dimensional colloidal systems : grain boundaries and confinement

Author

Skinner, Thomas Olof Edwin and Dullens, Roel P. A.

Subjects
541.345, Physical & theoretical chemistry, Structure of interfaces, colloids, soft matter, grain boundaries, glasses, crystallisation, optical tweezers, optical microscopy
Abstract

The behaviour of colloidal particles in two-dimensional (2D) systems is addressed in real space and time using magnetic fields, optical tweezers and optical video microscopy. First, the fluctuations of a grain boundary in a 2D colloidal crystal are analysed. A real space analogue of the capillary fluctuation method is derived and successfully employed to extract the key parameters that characterise the grain boundary. Good agreement is also found with a fluctuation-dissipation based method recently suggested in simulation. Following on from analysis of the interface fluctuations, the properties of the individual grain boundary particles are analysed to investigate the long standing hypothesis that suggests that grain boundary particle dynamics are similar to those in supercooled liquids. The grain boundary particle dynamics display cage breaking at long times, highly heterogeneous particle dynamics and the formation of cooperatively moving regions along the interface, all typical behaviour of a supercooled liquid. Next, the frustration induced by confining colloidal particles inside a pentagonal environment is investigated. The state of the system is adjusted via two separate control parameters: the inter-particle interaction potential and the number density. A gradual crystalline to confined liquid-like transition is observed as the repulsive inter-particle interaction potential is decreased. In contrast, re-entrant orientational ordering and dynamical effects result as the number density of the confined colloidal particles is increased. Finally, the dynamics of colloidal particles distributed amongst a random array of fixed obstacle particles is probed as a function of both the mobile particle and fixed obstacle particle number densities. Increasing the mobile and the obstacle particle number density drives the system towards a glass transition. The dynamics of the free particles are shown to behave in a similar way to the normal glass transition at low obstacle density and more analogous to a localisation glass transition at high obstacle density.

Published
2012

9. A HaemSTAR-led, UK-wide 'flash-mob’ audit of ­intravenous immunoglobulin use in immune ­thrombocytopenia

Author

Nicolson, Phillip, Perry, Rita, Fisher, Amelia, Scott, Gemma, Magill, Laura, Chan-Lam, Dominique, Thorpe, Alice, Macheta, Mac, Carter-Brzezinski, Luke, Ackroyd, Sam, Katumba, Alvin, Bradbury, Charlotte, Jen, Sheila, Camillieri, Marquita, Besser, Martin, Bull, Tom, Leighton, Katherine, Ayalew, Yezenash, Willan, John, Watson, Edmund, Oshinyemi, Pamela, Upadhye, Yogesh, Pickard, Keir, Swart-Rimmer, Imogen, Knott, Chloe, Chown, Sally, Crolla, Francesca, Quinn, Daire, McLeod-Kennedy, Lindsay, Oun, Hajer, McDermott, Christopher, Walker, Mairi, Mullally, Ryan, Herlihy, Naoimh, Shah, Gulnaz, Doyle, Andrew, Robinson, Susan, Sayar, Zara, Pryor, Rebecca, Peet, Chris, Shenouda, Amir, Venkatadasari, Indrani, Cartier, Jorge, Akay, Melek, Tsitsikas, Dimitris, Sivapalaratnam, Suthesh, Cooper, Nichola, Lentaigne, Claire, Bailey, Chris, Xu, Dan Mei, Janum, Sine, Mohan, Arunodaya, Kimberger, Katja, Kgologolo, Maipelo, Sevillano, Belen, Hanina, Sophie, Danga, Akila, Mustafa, Chira, Wilding, Charlotte, Trikha, Roochi, Wang, Han, Crossette-Thambiah, Cristina, Hastings, Andrew, Sreedhara, Sree, Wright, David, Batey, Laura, Atkin, Abigail, Davis, Sarah, Jaafar, Sarah, Ejaz, Ayesha, Biss, Tina, Swieton, Jennifer, Noh, Mohd Sharin Mohd, Gibson, Holly, Freeman, Tanya, Badaguma, Upekha, Kreze, Olivia, Kirkpatrick, Suriya, Suntharalingam, Surenthini, Kmonicek, Miroslab, Joffe, Michael, Halperin, Dan, Desborough, Michael, Rampotas, Alexandros, Dhillon, Elissa, Greaves, Paul, Blacker, Edward, Aiken, Laura, Boot, Jesca, Prasannan, Nithya, Kerr, Jonathan, Martin, Abi, Wexler, Sarah, Burney, Claire, Melly, Michelle, Nolan, Regina, Hipkins, Rupert, Kaddam, Israa, Elmoamly, Shereef, Darlow, Jennifer, Plews, Dianne, Shrubsole, Caroline, Loizou, Eleana, Garth, Louise, Peter, Hina, Wolf, Julia, Walia, Shivali, MacDonald, Vickie, Zaidi, Abbas, Dunk, Robert, Miah, Haroon, Miah, Atiqa, Tucker, David, Skinner, Thomas, Cakmak, Seda, Cakmak, Ipek, Hussein, Hayder, Buka, Richard, Wilson, Lydia, Talbot, Georgina, Qureshi, Hafiz, Wharin, Sarah, Dillon, Anna, Bailiff, Benjamin, McIlroy, Graham, Murray, Duncan, Seymour, Frances, Graham, Jane, Harrison, Samuel, Salhan, Beena, Sharpe, David, Thomas, Wayne, McCulloch, Rory, Crosbie, Nicola, Lowe, Gillian, and Hill, Quentin

Published
2019
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10. An atypical case of progressive multifocal leukoencephalopathy in a patient with high grade B-cell lymphoma causing diagnostic delay.

Author

Grant, Sabrina, Skinner, Thomas, Turner, Deborah, Griggs, Gareth, and Eve, Heather

Subjects
PROGRESSIVE multifocal leukoencephalopathy, DELAYED diagnosis, JOHN Cunningham virus, CENTRAL nervous system diseases, CEREBRAL hemispheres, OPPORTUNISTIC infections
Abstract

Progressive multifocal leukoencephalopathy (PML) is a rare disease of the central nervous system caused by opportunistic infection with JC virus. It presents in patients who are immunocompromised, and diagnosis is made by correlating clinical findings and radiological changes with the detection of JC virus in cerebrospinal fluid. Rarely, a brain biopsy is needed. A 72 year old with high grade B-cell lymphoma developed right arm weakness and limb ataxia shortly after his diagnosis. CNS involvement was excluded with a normal CT head, MRI brain/spine, and CSF examination. A paraneoplastic cause was suspected, and he received 5 cycles of Rituximab-containing chemotherapy to a complete metabolic remission. His neurology evolved during treatment despite serial MRI and CSF examination remaining normal. CSF and serum were both negative for JC virus by PCR. Following completion of chemotherapy, he deteriorated acutely with seizures and personality changes. It was only at this point that a repeat MRI showed new multiple scattered ring enhancing lesions within both cerebral hemispheres. The patient underwent a brain biopsy confirming JC virus positive-PML by immunohistochemistry and passed away one month later. This case illustrates the diagnostic challenges associated with PML and had several atypical features which led to diagnostic delay, specifically the onset of symptoms before starting immunochemotherapy, and the lack of radiological change despite evolving neurology. The eventual MRI abnormalities were not altogether classical for PML which, coupled with the JC-negativity in CSF and serum, meant a brain biopsy was required to reach the diagnosis. [ABSTRACT FROM AUTHOR]

Published
2023
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17. Towards a simple, comprehensive model of regular earthquakes and slow slip events, part II: two-dimensional model

Author

Gershenzon, Naum I. and Skinner, Thomas

Subjects
Physics - Geophysics, FOS: Physical sciences, Geophysics (physics.geo-ph)
Abstract

Although our existing one-dimensional (1D) model provides a successful quantitative description of rupture events, a 1D description is somewhat limited. We therefore derive a two-dimensional (2D) model which allows us to investigate characteristics of earthquakes (EQs) and slow slip events (SSEs) that are only apparent in a second dimension. We find that the leading edge of an EQ rupture in the direction of the global shear stress (x-direction) is wider in the plane of the crustal fault (y-direction) than the trailing edge. The direction of the slip velocity is primarily in the x-direction. EQ ruptures expand in both the x- and y-directions. In SSEs, the rupture also expands in both directions for a short period of time, then, after pulses are formed, there is no further expandsion, i.e., the pulse shape remains practically unchanged. The 2D simulations show the seismic moment (M) versus time (T) scaling law may be expressed by the relation , where . For EQs, is approximately equal to 3, while for SSEs, tends to 1 as the pulses develop and become fully established. The 2D model quantitatively describes the parameters of a seismic pulse in episodic tremor and slip (ETS) phenomena and also explains important features of non-volcanic tremor associated with this pulse, such as reverse tremor migration. The 2D model confirms the basic findings obtained previously by the 1D model: (i) The type of a seismic event, EQ or SSE, and the type of a rupture, crack-like or pulse-like, are determined solely by the fault strength, the ratio of the shear to normal stress, and the gradient in this ratio; (ii) The shape of a rupture and position of the maximum slip is determined by the spatial distribution of the initial stress., 24 pages, 8 figures

Published
2021

20. Optimal control RF pulses for excitation and suppression of NMR signals in a conductive medium.

Author

Kharkov, Boris, Strouk, Leonard, Skinner, Thomas E., and Jerschow, Alexej

Subjects
OPTIMAL control theory, ELECTRONIC excitation, RADIO frequency, SIGNAL processing, LITHIUM
Abstract

In this work, optimal control theory was used to design efficient excitation schemes in highly conductive materials, where both the radio frequency field strength and phase vary as a function of penetration depth. A pulse was designed to achieve phase alignment between signals at different depths within the conductor and thus to obtain higher signals from that region. In addition, an efficient suppression pulse was designed by insuring mutual suppression between the signals from various depths in the sample. The performance of the new approach was demonstrated experimentally for a bulk lithium sample for the excitation problem and for a biphasic metal/liquid sample for the selective suppression pulse. [ABSTRACT FROM AUTHOR]

Published
2018
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24. Effect of Tranexamic Acid on Bleeding Outcomes After Percutaneous Nephrolithotomy: A Systematic Review and Meta-analysis of Randomized Controlled Trials.

Author

MacDonald, Morgan, Ilie, Gabriella, Power, Liam, Whalen, Stewart, Parker, Robin, Skinner, Thomas A., and Powers, Andrea G. Lantz

Subjects
PERCUTANEOUS nephrolithotomy, RANDOMIZED controlled trials, HEMOGLOBINS, TRANEXAMIC acid, BLOOD transfusion, HEMORRHAGE, DATA extraction
Abstract

Purpose: We performed a systematic review and meta-analysis of the literature to evaluate the efficacy of the routine use of tranexamic acid (TXA) during percutaneous nephrolithotomy (PCNL). Methods: This systematic review was conducted following the updated reporting guidelines from PRISMA 2020. Results: In total, 275 titles and abstracts were reviewed, of which 20 were screened to be eligible for full text review. Of these 20 articles, 11 were selected for inclusion after full article evaluations. Seven of these 11 studies were seen as having a low risk of bias with a Jadad score of ≥3. These studies were included for data extraction. Once data were extracted, 964 patients were included. The primary outcome, blood transfusion rate, showed significant reduction with a ratio for transfusion rate of 0.34 [95% confidence interval (CI) (0.19 to 0.61), z = 3.61, p = 0.0003]. Mean hemoglobin (Hgb) drop and operative time were both shown to be reduced with the use of TXA. The mean difference for Hgb drop was −0.86 [95% CI (−1.26 to −0.46), z = 4.23, p < 0.0001]. Reduction in operative time showed a mean difference of −8.45 minutes [95% CI (−15.04 to −1.86), z = 2.51, p = 0.01]. Stone clearance was not shown to differ significantly between experimental and control groups, with a risk ratio of 1.28 [95% CI (0.89 to 1.84), z = 1.31, p = 0.19]. Conclusions: This meta-analysis revealed that the routine use of TXA at time of PCNL reduces the rates of blood transfusion, mean Hgb drop, and operative time. With the low cost of TXA and strong safety profile, stronger consideration should be given to the routine use of TXA during PCNL by endoscopic surgeons. [ABSTRACT FROM AUTHOR]

Published
2022
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31. Towards a simple, comprehensive model of regular earthquakes and slow slip events, part I: one-dimensional model

Author

Gershenzon, Naum I., Zhou, Cong, and Skinner, Thomas

Subjects
Physics - Geophysics, FOS: Physical sciences, Geophysics (physics.geo-ph)
Abstract

We have developed a model that describes the major characteristics of a rupture, ranging from regular earthquakes (EQs) to slow slip events (SSEs), including episodic tremor and slip (ETS). Previous model predictions, while accurate, are based on a highly idealized initial stress distribution and a simple velocity-dependent expression for friction. The full scope of the model has, therefore, not been fully demonstrated. Further developments, presented here, include more physically realistic treatments of both the initial conditions and friction. Model predictions are: (1) The type of a seismic event, i.e. regular EQ or SSE, is determined by the fault strength, the shear to normal stress ratio, and the gradient in the ratio. Quantitative values for these crucial parameters are also obtained here; (2) Rupture velocities for regular EQs range from a fraction of the shear wave velocity up to the supershear velocity. The maximum slip velocity for regular EQs is typically on the order of 1 m/s. For SSEs, the slip velocity ranges widely from a few cm/year up to 0.1 m/s. The magnitude of the stress drop may vary in the range from 1% to 10% of the initial shear stress for regular EQs and from 0.1% to 10% for the SSEs; (3) The rupture can expend as a crack-like mode or as a self-healing pulse mode. The type of rupture mode is determined by the stress ratio and its gradient. If stress heterogeneity has a step-like shape, the rupture is always crack-like. If the heterogeneity is localized, the rupture is crack-like for sufficiently large values of the stress and its gradient and is pulse-like for smaller values; (4) After an instability develops, rupture dynamics do not depend on the relative values of the rate-state a and b parameters, i.e., it does not matter if frictional sliding is velocity-weakening or velocity-strengthening. Models based on the rate-state are not consistent with this result., 45 pages, 13 figures

Published
2019

36. International Ultraviolet Explorer observations of Venus SO2 and SO

Author

Na, Chan Y, Esposito, Larry W, and Skinner, Thomas E

Subjects
Lunar And Planetary Exploration
Abstract

Results of recent International Ultraviolet Explorer observations of Venus made on January 20, 1987 and April 2 and 3, 1988 are presented along with a reanalysis of the 1979 observations (Conway et al., 1979). The observations indicate that the amount of sulfur dioxide at the cloud tops of Venus declined by a factor of 8 + or - 4 from 380 + or - 70 ppb in 1979 to 50 + or - 20 ppb in 1987 and 1988. These values are consistent with the Pioneer Venus results. Absorption features of sulfur monoxide are identified for the first time, and the SO mixing ratio above the cloud level is estimated to be 20 + or - 10 ppb for 1979. This is consistent with photochemical models by Winick and Stewart (1980) and Yung and DeMore (1982) and with the upper limit from Wilson et al. (1981).

Published
1990

37. Supercooled dynamics of grain boundary particles in two-dimensional colloidal crystals.

Author

Skinner, Thomas O. E., Aarts, Dirk G. A. L., and Dullens, Roel P. A.

Subjects
*SUPERCOOLED liquids, *CRYSTAL grain boundaries, *COLLOIDAL crystals, *VIDEO microscopy, *MOLECULAR dynamics, *SIMULATION methods & models
Abstract

We experimentally investigate the dynamics of particles constituting grain boundaries in a two-dimensional colloidal crystal, using video-microscopy. A clear plateau in the mean square displacement of the grain boundary particles is found, followed by an upswing indicative of cage breaking. The van Hove correlation functions and the non-Gaussian parameter show that grain boundary particle dynamics are highly heterogeneous. Furthermore, we identified clusters of cooperatively moving particles and analyzed the time-dependence of the weight-averaged mean cluster size. We find good correlation between the behavior of the mean square displacement, and the time dependence of the non-Gaussian parameter and the cluster size, as also reported for various supercooled systems. Our results therefore provide experimental support for the similarity between particle dynamics in grain boundaries and in supercooled liquids as suggested by recent computer simulations. [ABSTRACT FROM AUTHOR]

Published
2011
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40. Two-dimensional colloidal systems: grain boundaries and confinement

Author

Skinner, T, Skinner, Thomas, and Dullens, R

Subjects
Structure of interfaces, Physical & theoretical chemistry
Abstract

The behaviour of colloidal particles in two-dimensional (2D) systems is addressed in real space and time using magnetic fields, optical tweezers and optical video microscopy. First, the fluctuations of a grain boundary in a 2D colloidal crystal are analysed. A real space analogue of the capillary fluctuation method is derived and successfully employed to extract the key parameters that characterise the grain boundary. Good agreement is also found with a fluctuation-dissipation based method recently suggested in simulation. Following on from analysis of the interface fluctuations, the properties of the individual grain boundary particles are analysed to investigate the long standing hypothesis that suggests that grain boundary particle dynamics are similar to those in supercooled liquids. The grain boundary particle dynamics display cage breaking at long times, highly heterogeneous particle dynamics and the formation of cooperatively moving regions along the interface, all typical behaviour of a supercooled liquid. Next, the frustration induced by confining colloidal particles inside a pentagonal environment is investigated. The state of the system is adjusted via two separate control parameters: the inter-particle interaction potential and the number density. A gradual crystalline to confined liquid-like transition is observed as the repulsive inter-particle interaction potential is decreased. In contrast, re-entrant orientational ordering and dynamical effects result as the number density of the confined colloidal particles is increased. Finally, the dynamics of colloidal particles distributed amongst a random array of fixed obstacle particles is probed as a function of both the mobile particle and fixed obstacle particle number densities. Increasing the mobile and the obstacle particle number density drives the system towards a glass transition. The dynamics of the free particles are shown to behave in a similar way to the normal glass transition at low obstacle density and more analogous to a localisation glass transition at high obstacle density.

Published
2016

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