A5042424551- Quantum, superfluid, helium dynamics
- Atomic and Subatomic Physics Research
- Physics of Superconductivity and Magnetism
- Cold Atom Physics and Bose-Einstein Condensates
- Superconducting Materials and Applications
- High-pressure geophysics and materials
- Esophageal Cancer Research and Treatment
- Gastric Cancer Management and Outcomes
- Spacecraft and Cryogenic Technologies
- Advanced Condensed Matter Physics
- NMR spectroscopy and applications
- Esophageal and GI Pathology
- Quantum and electron transport phenomena
- Rare-earth and actinide compounds
- Advanced NMR Techniques and Applications
- Topological Materials and Phenomena
- Trauma and Emergency Care Studies
- Methane Hydrates and Related Phenomena
- COVID-19 and healthcare impacts
- Magneto-Optical Properties and Applications
- Superconducting and THz Device Technology
- Magnetic Properties and Applications
- Advanced Electrical Measurement Techniques
- Graphene research and applications
- Scientific Research and Discoveries
Royal Holloway University of London
2014-2024
Lancaster University
2024
Trinity College Dublin
2024
St. James's Hospital
2024
University of Southampton
2023
University of Amsterdam
2023
Amsterdam University Medical Centers
2023
Radboud University Nijmegen
2022
Radboud University Medical Center
2022
Nottingham University Hospitals NHS Trust
2013-2022
<h3>Importance</h3> Ninety-day mortality rates after esophagectomy are an indicator of the quality surgical oncologic management. Accurate risk prediction based on large data sets may aid patients and surgeons in making informed decisions. <h3>Objective</h3> To develop validate a model death within 90 days for cancer using International Esodata Study Group (IESG) database, largest existing prospective, multicenter cohort reporting standardized postoperative outcomes. <h3>Design, Setting,...
Abstract The focus of dark matter searches to date has been on Weakly Interacting Massive Particles (WIMPs) in the GeV/ $$c^2$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mi>c</mml:mi> <mml:mn>2</mml:mn> </mml:msup> </mml:math> -TeV/ mass range. direct, indirect and collider this range have extensive but ultimately unsuccessful, providing a strong motivation for widening search outside Here we describe new concept experiment, employing superfluid $$^3$$...
Patients who presented to their family doctors with previously uninvestigated dyspepsia of at least two weeks9 duration were recruited into a placebo controlled trial treatment ranitidine (150 mg twice daily) for six weeks. All patients examined by endoscopy before treatment, and those macroscopical abnormalities the examination was repeated after treatment. Of 604 recruited, 559 had endoscopy, whom 171 (30%) no apparent abnormality. 388 remaining, one third or more lesions. The high...
Results of zero-sound attenuation measurements in $^{3}\mathrm{He}$-$B$, at frequencies up to 60 MHz and pressures between 0 20 bars, are reported. At 30 above, a new feature is observed which bears the signature collective mode superfluid.
Confined Helium Helium-3 ( 3 He) has superfluid phases closely related to topological insulators and superconductors. In geometrical confinement, He is expected support exotic excitations, but its phase diagram largely unknown, as such measurements are experimentally challenging. Levitin et al. (p. 841 ) confine in a slab geometry of defined height use nuclear magnetic resonance probe. As predicted by theory, the authors find that confinement stabilizes some across larger portion with...
We report the results of radioactivity assays and heat leak calculations for a range common cryogenic materials, considered use in QUEST-DMC superfluid 3He dark matter detector. The bolometer, instrumented with nanomechanical resonators, will be sensitive to energy deposits from interactions. Events radioactive decays cosmic rays constitute significant background must precisely modelled, using combination material screening Monte Carlo simulations. However, presented here are wider interest...
The heat capacity and magnetization of a fluid 3He monolayer adsorbed on graphite plated with bilayer HD have been measured in the temperature range 1-60 mK. Approaching density at which solidifies into sqrt[7]xsqrt[7] commensurate solid, we observe an apparent divergence effective mass corresponding to T=0 Mott-Hubbard transition between 2D Fermi liquid magnetically disordered solid. observations are consistent Brinkman-Rice-Anderson-Vollhardt scenario for metal-insulator transition. We...
Two-dimensional helium-3 (3He) provides a simple model for the experimental investigation of emergence quantum complexity in strongly correlated Fermi system. We have observed two-dimensional, two-band heavy-fermion behavior bilayer films 3He atoms when adsorbed on surface graphite preplated by solid 4He. Thermodynamic measurements this system showed that relevant control parameter is total density film. The can be driven toward critical point at which effective mass appears to diverge,...
The nuclear magnetic susceptibility of $^{3}\mathrm{He}$ adsorbed on the surface graphite, plated with a monolayer solid $^{4}\mathrm{He}$, has been measured at densities less than 0.055 \AA{} $^{\mathrm{\ensuremath{-}}2}$ and temperatures down to 6 mK. A temperature-independent is observed low temperatures, which strongly enhanced over ideal-gas value, due quasiparticle interactions. inferred Landau-Fermi-liquid parameters allow comparison microscopic theories interacting Fermi systems.
We present the first measurements at millikelvin temperatures of both real and imaginary parts transverse-acoustic impedance an oscillating surface in contact with dilute solutions $^{3}\mathrm{He}$ $^{4}\mathrm{He}$, as well pure without a boundary layer $^{4}\mathrm{He}$. Except for $^{3}\mathrm{He}$, large departures from hydrodynamic behavior are found which inconsistent slip theories incorporating specular scattering boundary. The effects $^{4}\mathrm{rich}$ roughness discussed.
The width of the ferromagnetic resonance has been measured at 10 000 Mc/sec in polycrystalline mixed ferrites composition ${\mathrm{Co}}_{\ensuremath{\alpha}}{\mathrm{Ni}}_{1\ensuremath{-}\ensuremath{\alpha}}{\mathrm{Fe}}_{2}{\mathrm{O}}_{4}$, with $\ensuremath{\alpha}$ between 0 and 0.04. minimum line is found for $\ensuremath{\alpha}=0.025$ 20\ifmmode^\circ\else\textdegree\fi{}C. This, as well variation temperature, can be understood on basis known single crystal properties following...
In superfluid $^3$He-B confined in a slab geometry, domain walls between regions of different order parameter orientation are predicted to be energetically stable. Formation the spatially-modulated stripe phase has been proposed. We $^3$He 1.1 $\mu$m high microfluidic cavity and cooled it into B at low pressure, where is predicted. measured surface-induced distortion with NMR, sensitive formation domains. The results rule out phase, but consistent 2D modulated order.
Abstract Background Postoperative complications after resection of oesophagogastric carcinoma can result in considerable early morbidity and mortality. However, the long-term effects on survival are less clear. Methods All patients undergoing intentionally curative for oesophageal or gastric cancer between 2006 2016 were selected from an institutional database. Patients categorized by complication severity according to Clavien–Dindo classification (grades 0–V). Complications defined...
Abstract Background Large studies comparing totally minimally invasive oesophagectomy (TMIE) with laparoscopically assisted (hybrid) are lacking. Although randomized trials have compared TMIE open oesophagectomy, daily clinical practice does not always resemble the results reported in such trials. The aim of present study was to compare complications after invasive, hybrid and Ivor Lewis patients oesophageal cancer. Methods performed using data from International Esodata Study Group...
Abstract Quantum circuits interact with the environment via several temperature-dependent degrees of freedom. Multiple experiments to-date have shown that most properties superconducting devices appear to plateau out at T ≈ 50 mK – far above refrigerator base temperature. This is for example reflected in thermal state population qubits, excess numbers quasiparticles, and polarisation surface spins factors contributing reduced coherence. We demonstrate how remove this constraint by operating...
We describe here the design and performance of a current sensing noise thermometer using low Tc DC SQUID as front end amplifier. The is used to measure thermal in resistor temperature then obtained from Nyquist formula. fast, absolute precise usable over wide range below 4.2 K, principle down well 1 mK. excellent energy sensitivity SQUID, operated at fixed temperature, enables use relatively large resistor, mΩ range. This requires short averaging times when measuring spectrum fluctuations....
Measurements of the magnetization and heat capacity second layer ${}^{3}\mathrm{He}$ films adsorbed on graphite indicate that evolution exchange from antiferromagnetic to ferromagnetic arises a tuning competing processes. At certain coverages coexistence an with is clear manifestation, predicted by theory, frustration. anomaly system well described series expansions for 2D Heisenberg ferromagnet triangular lattice.
We report measurements of the nuclear magnetic susceptibility monolayer two-dimensional solid formed by $^{3}\mathrm{He}$ adsorbed on graphite plated with two atomic layers HD. A low-density is observed, consistent a \ensuremath{\surd}7 \ifmmode\times\else\texttimes\fi{} registered structure, which exhibits large antiferromagnetic exchange. distinct cusp in observed near 1 mK, suggestive phase transition. The evolution this and other features surface density discussed.
Measurements of the nuclear magnetic susceptibility multilayer films 3He adsorbed on graphite plated with a monolayer 4He are reported for surface densities up to 0.27 Å-2 and temperatures in range (6÷600) mK. The coverage dependence exchange constant has been measured; this is antiferromagnetic when second layer first solidifies becomes ferromagnetic formation fluid overlayer. second-layer solid density evolves stepwise fashion increasing coverage, while overlayer shows structure associated...
Measurements are reported which relate to the dissipation and superfluid density of $^{3}\mathrm{He}$-$A$ $^{3}\mathrm{He}$-$B$ flowing through a long rectangular channel cross section 48 \ensuremath{\mu}m \ifmmode\times\else\texttimes\fi{} 2.86 mm at currents between 5 ${10}^{\ensuremath{-}2}$ g ${\mathrm{cm}}^{\ensuremath{-}2}$ ${\mathrm{sec}}^{\ensuremath{-}1}$ ${10}^{\ensuremath{-}5}$ temperatures down $\frac{T}{{T}_{c}}=0.52$. The results show complex velocity dependence in both phases.