22 results on '"Sandhu, J.K."'
Search Results
2. Diagnosing Relativistic Electron Distributions in the Van Allen Radiation Belts
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KILLEY, SHANNON, Rae, I.J., Chakraborty, S., Smith, A.W., Bentley, S.N., Bakrania, M.R., Wainwright, R., Watt, C.E.J., and Sandhu, J.K.
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Open access - Abstract
Entry to the poster competition ran during Northumbria's Open Research and Reproducibility Conference 2023. Poster entries showcase open research practice in student work.
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- 2023
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3. ORW: Open Research and Reproducibility Conference Poster Competition
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Research Data, Northumbria, Hoult, Lauren, Smith, Michael, Wetherell, Mark, Edginton, Trudi, OGBANGA, ONENGIYE, Nelson, Andrew, Smith, Darren, Procopio, Noemi, PERRONE, VALENTINA, Randolph-Quinney, Patrick, Smailes, David, WADE, DEBORAH, MEGARITIS, DIMITRIOS, Buekers, J., Bonci, T., Hume, E., Yarnall, A., Amigo, E.M., Brown, P., Buckley, C., Del Din, S., Echevarria, C., Alcock, L., Mazzà, C., Rochester, L., Garcia Aymerich, J., Vogiatzis, Ioannis, CROUCH, FIONA, Merlane, Helen, Rajanayagam, Heshachanaa, Moore, Jen, Hume, Joanna, Das, Julia, Barry, Gill, Vitorio, Rodrigo, Walker, Richard, McDonald, Claire, Morris, Rosie, Stuart, Samuel, Maughan, Leah, Branson, Rachel, Haskin, Marion, Colborne, Yasmin, NGUYEN, NGOC, Liwan, Vilma B., Mai, Thao T. P., Friedman, Samantha, Killey, Shannon, Rae, I.J., Chakraborty, Suman, Smith, A.W., Bentley, S.N., Bakrania, M.R., Wainwright, R., Watt, C.E.J., and Sandhu, J.K.
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Open access - Abstract
Entries to the poster competition ran during Northumbria's Open Research and Reproducibility Conference as part of Open Research Week 2023. Poster entries showcase open research practice in student and academic work. Titles WINNER Positive expressive writing interventions, subjective health and wellbeing: A systematic review, Lauren Hoult, Dr Michael Smith, Prof Mark Wetherell & Dr Trudi Edginton WINNER Micro-detectives: Forensic profiling with microbes, Nengi Ogbanga, Andrew Nelson, Darren Smith & Noemi Procopio WINNER Cementochronology: About the “tree rings” in our teeth, Valentina Perrone, Patrick Randolph-Quinney & Noemi Procopio Larger, more powerful studies: More work. But big rewards!, David Smailes Promote (or learn about) open research via a Reproducibilitea Journal Club, David Smailes To explore how a Breastfeeding Closed Facebook group administered by volunteers with additional breastfeeding training influences women’s experiences, particularly for those women for whom breastfeeding is not their cultural norm, Deborah Wade Impact of symptoms and disease severity on digital mobility outcomes in COPD, D. Megaritis, J. Buekers, T. Bonci, E. Hume, L. Alcock, A. Yarnall, E. M. Amigo, P. Brown, C. Buckley, S. Del Din, C. Echevarria, C. Mazzà, L. Rochester, J. Garcia Aymerich & I. Vogiatzis Growing my research village, Fiona Crouch Dying to Care. A constructivist grounded theory study identifying what factors prepare student nurses to care for dying patients, Helen Merlane Development of Innovative MODular Building System with Enhanced Fire, Environmental, Structural and Thermal Performance (MOD-FEST), Heshachanaa Rajanayagam How does garment cut influence the perception of attractiveness in the male somatotype? A comparative study of the focus of attraction on specific areas of the male body and its adaptation to inform garment cut in the UK, Jenni Moore The more-than-digital scrapmap: Exploring the generative possibilities of qualitative digital data, Joanna Hume Technological visuo-cognitive training in Parkinson’s disease: Preliminary findings from a pilot randomised controlled trial, Julia Das, Gill Barry, Rodrigo Vitorio, Richard Walker, Claire McDonald, Rosie Morris & Samuel Stuart Library support for open research: How the University Library can support you to make your work more open…, Leah Maughan & Rachel Branson A Phenomenological study into the experience of training to perform Intermittent Self Catheterisation (ISC) from the perspective of the Patient and the Nurse, Marion Haskin Be thankful to be joyful: Gratitude writing for wellbeing, Michael A. Smith & Yasmin Colborne Improving cultural understanding and 21st century skills with COIL, Ngoc D. Nguyen, Vilma B. Liwan & Thao T. P. Mai ‘It helps make the fuzzy go away’: Autistic adults’ reflections upon nature and wellbeing during the Covid-19 pandemic and across the life course, Dr Samantha Friedman Diagnosing relativistic electron distributions in the Van Allen radiation belts, S. Killey, I.J. Rae, S. Chakraborty, A.W. Smith, S.N. Bentley, M. R. Bakrania, R. Wainwright, C.E.J. Watt, & J. K. Sandhu
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- 2023
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4. Obesity and outcomes in patients hospitalized with pneumonia
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Kahlon, S., Eurich, D.T., Padwal, R.S., Malhotra, A., Minhas-Sandhu, J.K., Marrie, T.J., and Majumdar, S.R.
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- 2013
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5. Impact of guideline-concordant antibiotics and macrolide/β-lactam combinations in 3203 patients hospitalized with pneumonia: prospective cohort study
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Asadi, L., Eurich, D.T., Gamble, J.M., Minhas-Sandhu, J.K., Marrie, T.J., and Majumdar, S.R.
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- 2013
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6. Statistical comparison of electron loss and enhancement in the outer radiation belt during storms
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Walton, S. D., Forsyth, C., Rae, I.J., Meredith, N.P., Sandhu, J.K., Walach, M.‐T., Murphy, K.R., Walton, S. D., Forsyth, C., Rae, I.J., Meredith, N.P., Sandhu, J.K., Walach, M.‐T., and Murphy, K.R.
- Abstract
The near-relativistic electron population in the outer Van Allen radiation belt is highly dynamic and strongly coupled to geomagnetic activity such as storms and substorms, which are driven by the interaction of the magnetosphere with the solar wind. The energy, content and spatial extent of electrons in the outer radiation belt can vary on timescales of hours to days, dictated by the continuously evolving influence of acceleration and loss processes. While net changes in the electron population are directly observable, the relative influence of different processes is far from fully understood. Using a continuous 12-year dataset from the Proton Electron Telescope (PET) on board the Solar Anomalous Magnetospheric Particle Explorer (SAMPEX), we statistically compare the relative variations of trapped electrons to those in the bounce loss cone. Our results show that there is a proportional increase in flux entering the bounce loss cone outside the plasmapause during storm main phase and early recovery phase. Loss enhancement is sustained on the dawnside throughout the recovery phase while loss on the duskside is enhanced around minimum Sym-H and quickly diminishes. Spatial variations are also examined in relation to geomagnetic activity, making comparisons to possible causal wave modes such as whistler-mode chorus and plasmaspheric hiss.
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- 2022
7. ULF Wave Driven Radial Diffusion During Geomagnetic Storms: A Statistical Analysis of Van Allen Probes Observations
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Sandhu, J.K. Rae, I.J. Wygant, J.R. Breneman, A.W. Tian, S. Watt, C.E.J. Horne, R.B. Ozeke, L.G. Georgiou, M. Walach, M.-T.
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Physics::Space Physics - Abstract
The impact of radial diffusion in storm time radiation belt dynamics is well-debated. In this study we quantify the changes and variability in radial diffusion coefficients during geomagnetic storms. A statistical analysis of Van Allen Probes data (2012–2019) is conducted to obtain measurements of the magnetic and electric power spectral densities for Ultra Low Frequency (ULF) waves, and corresponding radial diffusion coefficients. The results show global wave power enhancements occur during the storm main phase, and continue into the recovery phase. Local time asymmetries show sources of wave power are both external solar wind driving and internal sources from coupling with ring current ions and substorms. Wave power enhancements are also observed at low L values (L
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- 2021
8. ULF wave driven radial diffusion during geomagnetic storms: A statistical analysis of Van Allen Probes observations
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Sandhu, J.K., Rae, I.J., Wygant, J.R., Breneman, A.W., Tian, S., Watt, C.E.J., Horne, R.B., Ozeke, L.G., Georgiou, M., Walach, M.‐T., Sandhu, J.K., Rae, I.J., Wygant, J.R., Breneman, A.W., Tian, S., Watt, C.E.J., Horne, R.B., Ozeke, L.G., Georgiou, M., and Walach, M.‐T.
- Abstract
The impact of radial diffusion in storm time radiation belt dynamics is well‐debated. In this study we quantify the changes and variability in radial diffusion coefficients during geomagnetic storms. A statistical analysis of Van Allen Probes data (2012 − 2019) is conducted to obtain measurements of the magnetic and electric power spectral densities for Ultra Low Frequency (ULF) waves, and corresponding radial diffusion coefficients. The results show global wave power enhancements occur during the storm main phase, and continue into the recovery phase. Local time asymmetries show sources of wave power are both external solar wind driving and internal sources from coupling with ring current ions and substorms. Wave power enhancements are also observed at low L values (L < 4). The accessibility of wave power to low L is attributed to a depression of the Alfvén continuum. The increased wave power drives enhancements in both the magnetic and electric field diffusion coefficients by more than an order of magnitude. Significant variability in diffusion coefficients is observed, with values ranging over several orders of magnitude. A comparison to the Kp parameterised empirical model of Ozeke et al. (2014) is conducted and indicates important differences during storm times. Although the electric field diffusion coefficient is relatively well described by the empirical model, the magnetic field diffusion coefficient is approximately ∼ 10 times larger than predicted. We discuss how differences could be attributed to dataset limitations and assumptions. Alternative storm‐time radial diffusion coefficients are provided as a function of L* and storm phase.
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- 2021
9. Implications of serial measurements of natriuretic peptides in heart failure: insights from BIOSTAT‐CHF
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Israr, Muhammad Zubair, Salzano, Andrea, Yazaki, Yoshiyuki, Voors, Adriaan A., Ouwerkerk, Wouter, Anker, Stefan D., Cleland, John G.F., Dickstein, Kenneth, Metra, Marco, Samani, Nilesh J., Ng, Leong L., Suzuki, Toru, Anker, S.D., Cleland, J.G., Dickstein, K., Filippatos, G., Hillege, H.L., Lang, C.C., Metra, M., Ng, L., Ponikowski, P., Samani, N., Veldhuisen, D.J., Zannad, F., Zwinderman, A.H., Bulgari, M., Lombardi, C., Carubelli, V., Lazzarini, Valentina, Rovetta, Riccardo, Magatelli, Marco, Castrini, Isotta, Bettari, Luca, Cosmi, Franco, Correale, Michele, Di Biase, Matteo, Fratini, Simona, Limongelli, Giuseppe, Parati, Gianfranco, Penco, Maria, Zaccà, Valerio, Voors, A.A., Haehling, S., Ebner, N., Springer, J., Diek, M., Lainscak, M, Koekemoer, Andrea, Papakonstantinou, Manolo, Hall, Leanne M, Romaine, Simon R, Romaine, Christopher P, Thompson, John R, Harst, Pim, Jones, D.J.L., Willingale, R., Cao, H.T., Sandhu, J.K., Quinn, P.A., Patel, H., Auluck, J., Hakimi, A., Lennep, H.W.O. Roeters, Liem, A., Ghraboghly, A., Dunselman, P.H.J.M., Hoogslag, P.A.M., Linssen, G.C.M., Van Haelst, P.L., Lok, D.J., Zinzius, P.Y., Godenir, J.P., Madeleine, CH Marie, Thisse, J.Y., Martelet, M., Deforet, M.F., Delarche, N., Leduc, J.J., Galinier, M., Neuder, Y., Eschalier, R., Clerfond, G., Benetos, A., Khalife, K., Düngen, H., Petrović, V., Bratislav, A., Otašević, P., Trifunović, N., Seferović, P. M., Pavlović, M., Nešković, A.N., Radovanović, S., Lainščak, M., Ravnikar, T., Dimković, S., Kolokathis, F., Karavidas, A., Patsilinakos, S., Kitsiou, M., Kyriakidis, Z., Makridis, P., Mantas, I., Douras, A., Rentoukas, E., Barbetseas, J., Karvounis, H., Penco, M., Zacà, V., Calabrò, R., Di Biase, M., Parati, G., Cosmi, F., Dahlström, U., Lund, L.H., Persson, H., Otterstad, J.E., Jortveit, J., Hole, T.H.O., Gjertsen, E., Aaser, E., Berkowski, P., Ogorek, M., Jurczyk, A., Sokolowski, A., Szafran, B., Hof, M.H.P., Ouwerkerk, W., Lang, C C, Choy, A M, Doney, A, Palmer, C, Morris, A, Guthrie, B, Parry, H, Tavendale, R, Heather, Duncan, Rutherford, Lynn, Waldie, Helen, Mohan, Mohanpradeep, Baig, Fatima, Hopkinson, Pippa, Levin, Daniel, Francis, Mark, Bryson, Valerie, Dawson, Dana, Frenneaux, Michael, Denvir, Martin, Flint, Laura, Robertson, Shirley, Gardner, Roy, McAdam, Marion, McGovern, Kirsty, McMurray, J., Campbell, Ross, and Cannon, Jane
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R1 - Abstract
No abstract available.
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- 2020
10. Plasma proteomic approach in patients with heart failure: insights into pathogenesis of disease progression and potential novel treatment targets
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Cao, T.H. Jones, D.J.L. Voors, A.A. Quinn, P.A. Sandhu, J.K. Chan, D.C.S. Parry, H.M. Mohan, M. Mordi, I.R. Sama, I.E. Anker, S.D. Cleland, J.G. Dickstein, K. Filippatos, G. Hillege, H.L. Metra, M. Ponikowski, P. Samani, N.J. Van Veldhuisen, D.J. Zannad, F. Lang, C.C. Ng, L.L.
- Abstract
Aims: To provide insights into pathogenesis of disease progression and potential novel treatment targets for patients with heart failure by investigation of the plasma proteome using network analysis. Methods and results: The plasma proteome of 50 patients with heart failure who died or were rehospitalised were compared with 50 patients with heart failure, matched for age and sex, who did not have an event. Peptides were analysed on two-dimensional liquid chromatography coupled to tandem mass spectrometry (2D LC ESI-MS/MS) in high definition mode (HDMSE). We identified and quantified 3001 proteins, of which 51 were significantly up-regulated and 46 down-regulated with more than two-fold expression changes in those who experienced death or rehospitalisation. Gene ontology enrichment analysis and protein–protein interaction networks of significant differentially expressed proteins discovered the central role of metabolic processes in clinical outcomes of patients with heart failure. The findings revealed that a cluster of proteins related to glutathione metabolism, arginine and proline metabolism, and pyruvate metabolism in the pathogenesis of poor outcome in patients with heart failure who died or were rehospitalised. Conclusions: Our findings show that in patients with heart failure who died or were rehospitalised, the glutathione, arginine and proline, and pyruvate pathways were activated. These pathways might be potential targets for therapies to improve poor outcomes in patients with heart failure. © 2019 The Authors. European Journal of Heart Failure published by John Wiley & Sons Ltd on behalf of European Society of Cardiology.
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- 2020
11. Substorm ‐ Ring Current Coupling: A comparison of isolated and compound substorms
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Sandhu, J.K., Rae, I.J., Freeman, M.P., Gkioulidou, M., Forsyth, C., Reeves, G.D., Murphy, K.R., Walach, M.-T., Sandhu, J.K., Rae, I.J., Freeman, M.P., Gkioulidou, M., Forsyth, C., Reeves, G.D., Murphy, K.R., and Walach, M.-T.
- Abstract
Substorms are a highly variable process, which can occur as an isolated event or as part of a sequence of multiple substorms (compound substorms). In this study we identify how the low energy population of the ring current and subsequent energization varies for isolated substorms compared to the first substorm of a compound event. Using observations of H+ and O+ ions (1 eV to 50 keV) from the Helium Oxygen Proton Electron instrument onboard Van Allen Probe A, we determine the energy content of the ring current in L‐MLT space. We observe that the ring current energy content is significantly enhanced during compound substorms as compared to isolated substorms by ~ 20‐30%. Furthermore, we observe a significantly larger magnitude of energization (by ~ 40‐50%) following the onset of compound substorms relative to isolated substorms. Analysis suggests that the differences predominantly arise due to a sustained enhancement in dayside driving associated with compound substorms compared to isolated substorms. The strong solar wind driving prior to onset results in important differences in the time history of the magnetosphere, generating significantly different ring current conditions and responses to substorms. The observations reveal information about the substorm injected population and the transport of the plasma in the inner magnetosphere.
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- 2019
12. How well can we estimate Pedersen conductance from the THEMIS white-light all-sky cameras?
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Lam, Mai Mai, Freeman, Mervyn P., Jackman, C.M., Rae, I.J., Kalmoni, N.M.E., Sandhu, J.K., Forsyth, C., Lam, Mai Mai, Freeman, Mervyn P., Jackman, C.M., Rae, I.J., Kalmoni, N.M.E., Sandhu, J.K., and Forsyth, C.
- Abstract
We show that a THEMIS (Time History of Events and Macroscale Interactions during Substorms) white‐light all‐sky imager (ASI) can estimate Pedersen conductance with an uncertainty of 3 mho or 40%. Using a series of case studies over a wide range of geomagnetic activity, we compare estimates of Pedersen conductance from the backscatter spectrum of the Poker Flat Advanced Modular Incoherent Scatter Radar (ISR) with auroral intensities. We limit this comparison to an area bounding the radar measurements and within a limited area close to, (but off) imager zenith. We confirm a linear relationship between conductance and the square root of auroral intensity predicted from a simple theoretical approximation. Hence we extend a previous empirical result found for green‐line emissions to the case of white‐light off‐zenith emissions. The difference between the radar conductance and the best‐fit relationship has a mean of ‐0.76 ± 4.8 mho, and a relative mean difference of 21% ± 78%. The uncertainties are reduced to ‐0.72 ± 3.3 mho and 0% ± 40% by averaging conductance over 10 minutes, which we attribute to the time that auroral features take to move across the imager field being greater than the 1 minute resolution of the radar data. Our results demonstrate and calibrate the use of THEMIS ASIs for estimating Pedersen conductance. This technique allows the extension of estimates of Pedersen conductance from ISRs to derive continental‐scale estimates on scales of ~1‐10 minutes and ~100 km2. It thus complements estimates from low‐altitude satellites, satellite auroral imagers, and ground‐based magnetometers.
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- 2019
13. Variations of high-latitude geomagnetic pulsation frequencies: a comparison of time-of-flight estimates and IMAGE magnetometer observations
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Sandhu, J.K., Yeoman, T.K., James, M.K., Rae, I.J., and Fear, R.C.
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Physics::Space Physics - Abstract
The fundamental eigenfrequencies of standing Alfvén waves on closed geomagnetic field lines are estimated for the region spanning 5.9≤L < 9.5 over all MLT (Magnetic Local Time). The T96 magnetic field model and a realistic empirical plasma mass density model are employed using the time-of-flight approximation, refining previous calculations that assumed a relatively simplistic mass density model. An assessment of the implications of using different mass density models in the time-of-flight calculations is presented. The calculated frequencies exhibit dependences on field line footprint magnetic latitude and MLT, which are attributed to both magnetic field configuration and spatial variations in mass density. In order to assess the validity of the time-of-flight calculated frequencies, the estimates are compared to observations of FLR (Field Line Resonance) frequencies. Using IMAGE (International Monitor for Auroral Geomagnetic Effects) ground magnetometer observations obtained between 2001 and 2012, an automated FLR identification method is developed, based on the cross-phase technique. The average FLR frequency is determined, including variations with footprint latitude and MLT, and compared to the time-of-flight analysis. The results show agreement in the latitudinal and local time dependences. Furthermore, with the use of the realistic mass density model in the time-of-flight calculations, closer agreement with the observed FLR frequencies is obtained. The study is limited by the latitudinal coverage of the IMAGE magnetometer array, and future work will aim to extend the ground magnetometer data used to include additional magnetometer arrays.
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- 2018
14. Using matrix assisted laser desorption ionisation mass spectrometry (MALDI-MS) profiling in order to predict clinical outcomes of patients with heart failure
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Cao, T.H. Jones, D.J.L. Quinn, P.A. Chan, D.C.S. Hafid, N. Parry, H.M. Mohan, M. Sandhu, J.K. Anker, S.D. Cleland, J.G. Dickstein, K. Filippatos, G. Hillege, H.L. Metra, M. Ponikowski, P. Samani, N.J. Van Veldhuisen, D.J. Zannad, F. Zwinderman, A.H. Voors, A.A. Lang, C.C. Ng, L.L.
- Abstract
Background: Current risk prediction models in heart failure (HF) including clinical characteristics and biomarkers only have moderate predictive value. The aim of this study was to use matrix assisted laser desorption ionisation mass spectrometry (MALDI-MS) profiling to determine if a combination of peptides identified with MALDI-MS will better predict clinical outcomes of patients with HF. Methods: A cohort of 100 patients with HF were recruited in the biomarker discovery phase (50 patients who died or had a HF hospital admission vs. 50 patients who did not have an event). The peptide extraction from plasma samples was performed using reversed phase C18. Then samples were analysed using MALDI-MS. A multiple peptide biomarker model was discovered that was able to predict clinical outcomes for patients with HF. Finally, this model was validated in an independent cohort with 100 patients with HF. Results: After normalisation and alignment of all the processed spectra, a total of 11,389 peptides (m/z) were detected using MALDI-MS. A multiple biomarker model was developed from 14 plasma peptides that was able to predict clinical outcomes in HF patients with an area under the receiver operating characteristic curve (AUC) of 1.000 (p = 0.0005). This model was validated in an independent cohort with 100 HF patients that yielded an AUC of 0.817 (p = 0.0005) in the biomarker validation phase. Addition of this model to the BIOSTAT risk prediction model increased the predictive probability for clinical outcomes of HF from an AUC value of 0.643 to an AUC of 0.823 (p = 0.0021). Moreover, using the prediction model of fourteen peptides and the composite model of the multiple biomarker of fourteen peptides with the BIOSTAT risk prediction model achieved a better predictive probability of time-to-event in prediction of clinical events in patients with HF (p = 0.0005). Conclusions: The results obtained in this study suggest that a cluster of plasma peptides using MALDI-MS can reliably predict clinical outcomes in HF that may help enable precision medicine in HF. © 2018 The Author(s).
- Published
- 2018
15. 267 Regional disparities in healthcare utilization and costs of atopic dermatitis
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Wu, K.K., primary, Sandhu, J.K., additional, and Armstrong, A.W., additional
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- 2019
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16. Energization of the ring current by substorms
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Sandhu, J.K., Rae, I.J., Freeman, Mervyn P., Forsyth, C., Gkioulidou, M., Reeves, G.D., Spence, H.E., Jackman, C.M., Lam, M.M., Sandhu, J.K., Rae, I.J., Freeman, Mervyn P., Forsyth, C., Gkioulidou, M., Reeves, G.D., Spence, H.E., Jackman, C.M., and Lam, M.M.
- Abstract
The substorm process releases large amounts of energy into the magnetospheric system, although where the energy is transferred to and how it is partitioned remains an open question. In this study, we address whether the substorm process contributes a significant amount of energy to the ring current. The ring current is a highly variable region, and understanding the energization processes provides valuable insight into how substorm-ring current coupling may contribute to the generation of storm conditions and provide a source of energy for wave driving. In order to quantify the energy input into the ring current during the substorm process, we analyze Radiation Belt Storm Probes Ion Composition Experiment and Helium Oxygen Proton Electron ion flux measurements for H+, O+, and He+. The energy content of the ring current is estimated and binned spatially for L and magnetic local time. The results are combined with an independently derived substorm event list to perform a statistical analysis of variations in the ring current energy content with substorm phase. We show that the ring current energy is significantly higher in the expansion phase compared to the growth phase, with the energy enhancement persisting into the substorm recovery phase. The characteristics of the energy enhancement suggest the injection of energized ions from the tail plasma sheet following substorm onset. The local time variations indicate a loss of energetic H+ ions in the afternoon sector, likely due to wave-particle interactions. Overall, we find that the average energy input into the ring current is similar to 9% of the previously reported energy released during substorms. Plain Language Summary The Earth's near-space environment is populated by energetic charged particles, whose motion is largely controlled by the global geomagnetic field. This region, known as the magnetosphere, is highly dynamic and variable, strongly coupled to the solar wind (a continuous stream of charged particles o
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- 2018
17. The dependence of magnetospheric plasma mass loading on geomagnetic activity using Cluster
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Sandhu, J.K., Yeoman, T.K., Rae, I.J., Fear, R.C., Dandouras, I., Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)
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ion composition ,WHISPER ,Cluster ,[SDU]Sciences of the Universe [physics] ,F300 ,Physics::Space Physics ,geomagnetic storms ,F800 ,F600 ,mass density ,CODIF - Abstract
International audience; Understanding changes in the magnetospheric mass density during disturbed geomagnetic conditions provides valuable insight into the dynamics and structure of the environment. The mass density plays a significant role in a variety of magnetospheric processes, such as wave propagation, magnetic reconnection rates, and radiation belt dynamics. In this study, the spatial variations of total plasma mass density are explored through the analysis of Cluster observations. Data from the WHISPER (Waves of High frequency and Sounder for Probing of Electron density by Relaxation) and CODIF (ion Composition and Distribution Function analyzer) instruments, on board the four Cluster spacecraft for a time interval spanning 2001-2012, are used to determine empirical models describing the distribution of the total plasma mass density along closed geomagnetic field lines. The region considered covers field lines within 5.9≤L < 9.5, corresponding to the outer plasmasphere, plasmatrough, and near-Earth plasma sheet. This study extends previous work to examine and quantify spatial variations in the electron density, average ion mass, and total plasma mass density with Dst index. The results indicate that during periods of enhanced ring current strength, electron density is observed to decrease and average ion mass is observed to increase, compared with quiet geomagnetic conditions. The combination of these variations shows that although heavy ion concentration is enhanced, the decrease in plasma number density results in a general decrease in total plasma mass density during disturbed geomagnetic conditions. The observed decrease in mass density is in contrast to prevailing understanding and, due to the dependence of the Alfvén speed on mass density, has important implications for a range of plasma processes during storm time conditions (e.g., propagation of wave modes).
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- 2017
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18. 287 Impact of skin infections on medical expenditures in patients with atopic dermatitis
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Sandhu, J.K., primary, Salame, N., additional, Ehsani-Chimeh, N., additional, and Armstrong, A.W., additional
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- 2018
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19. [P149]: Differential DNA methylation and histone acetylation of Sox2 SRR1 and SRR2 enhancers control its expression in neurons and astrocytes
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Sikorska, M., primary, Jezierski, A., additional, Sandhu, J.K., additional, Deb-Rinker, P., additional, Charlebois, C., additional, Ribecco-Lutkiewicz, M., additional, Bani-Yaghoub, M., additional, and Walker, P.R., additional
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- 2006
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20. Mutatect: a mouse tumour model for detecting radiation-induced mutations in vivo
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Birnboim, H.C., Wilkinson, D., Sandhu, J.K., McLean, J.R., and Ross, W.
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- 1999
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21. Complexes of ditertiary phosphine and arsine oxides with metal ions—XI. Complexes of tin(IV) halides with oxides of ditertiary phosphine and arsine
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Sandhu, S.S., primary, Sandhu, J.K., additional, and Sandhu, G.K., additional
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- 1977
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22. Differential DNA methylation and histone acetylation of Sox2 SRR1 and SRR2 enhancers control its expression in neurons and astrocytes
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Sikorska, M., Jezierski, A., Sandhu, J.K., Deb-Rinker, P., Charlebois, C., Ribecco-Lutkiewicz, M., Bani-Yaghoub, M., and Walker, P.R.
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- 2006
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