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Search Results: 1 - 10 of 1137 matches for " Natalie Blencowe "
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A gastrointestinal stromal tumour presenting incidentally with haemorrhage and perforation associated with a Meckel's diverticulum: a case report
Richard Woolf, Natalie Blencowe, Karim Muhammad, David Paterson, Geoff Pye
Journal of Medical Case Reports , 2009, DOI: 10.4076/1752-1947-3-7423
Abstract: A 59-year-old Caucasian man presented with acute right iliac fossa pain with localized peritonism. At surgery, he was found to have a perforated and haemorrhagic Meckel's diverticulum, associated with a gastrointestinal stromal tumour within the apex of the diverticulum. The absence of necrosis and a low mitotic rate indicated primary resection with subsequent computed tomography surveillance to be the most appropriate management strategy.We report a unique triad of complications associated with the presentation of a Meckel's diverticulum. This article reviews this common congenital abnormality and discusses the management of a gastrointestinal tumour. Meckel's diverticulum will mimic other intra-abdominal pathologies in presentation and should therefore often be considered as a differential diagnosis.This is the first reported case of perforation and haemorrhage of a Meckel's diverticulum leading to the incidental finding of a gastrointestinal stromal tumour within the diverticulum. Meckel's diverticulum is the most common congenital abnormality of the gastrointestinal tract, however, when symptomatic, it is often misdiagnosed at presentation. Common complications presenting in adults include bleeding, obstruction, diverticulitis and perforation. Tumours within a Meckel's diverticulum are a rare but recognised complication.A 59-year-old Caucasian man presented with peri-umbilical pain that had localized to the right iliac fossa. On examination, he was tender in the right iliac fossa, with localized peritonism. His white cell count was 10.2 × 109 (neutrophils 8.1 × 109) and with C-reactive protein (CRP) <5. Acute appendicitis was diagnosed clinically and a diagnostic laparoscopy performed.A perforated Meckel's diverticulum was found, associated with free intra-abdominal fluid and haemorrhage. At subsequent laparotomy, 75 mm of small bowel was resected and primary anastamosis was performed. Histology confirmed a Meckel's diverticulum and with a 25 mm area of perforat
Setting up kangaroo mother care at Queen Elizabeth Central Hospital, Blantyre - a practical approach
H Blencowe, EM Molyneux
Malawi Medical Journal , 2005,
Quantum energy flow, dissipation and decoherence in mesoscopic dielectric structures
M. P. Blencowe
Physics , 1998, DOI: 10.1016/S0921-4526(98)01247-2
Abstract: We first present a summary of recent results concerning the phononic energy transport properties of mesoscopic, suspended dielectric wires. We then discuss some related open problems concerning the fundamental lower limits on the vibrational damping rates of submicron-sized cantilever structures and also the possibility to create and detect quantum superpositions of spatially separated states for such structures.
Quantum energy flow in mesoscopic dielectric structures
M. P. Blencowe
Physics , 1998, DOI: 10.1103/PhysRevB.59.4992
Abstract: We investigate the phononic energy transport properties of mesoscopic, suspended dielectric wires. The Landauer formula for the thermal conductance is derived and its universal aspects discussed. We then determine the variance of the energy current in the presence of a steady state current flow. In the final part, some initial results are presented concerning the nature of the temperature fluctuations of a mesoscopic electron gas thermometer due to the absorption and emission of wire phonons.
Effective Field Theory Approach to Gravitationally Induced Decoherence
M. P. Blencowe
Physics , 2012, DOI: 10.1103/PhysRevLett.111.021302
Abstract: Adopting the viewpoint that the standard perturbative quantization of general relativity provides an effective description of quantum gravity that is valid at ordinary energies, we show that gravity as an environment induces the rapid decoherence of stationary matter superposition states when the energy differences in the superposition exceed the Planck energy scale.
Intrinsic noise of a micro-mechanical displacement detector based on the radio-frequency single-electron transistor
Yong Zhang,Miles Blencowe
Physics , 2001, DOI: 10.1063/1.1453494
Abstract: We investigate the intrinsic noise of a micro-mechanical displacement detector based on the radio-frequency single-electron transistor (rf-SET). Using the noise analysis of a SET by Korotkov as our starting point, we determine the spectral density of the displacement noise due to the tunneling current shot noise. The resulting mechanical displacement noise decreases in inverse proportion to the increasing gate voltage. In contrast, the displacement noise due to the fluctuating SET island charge increases approximately linearly with increasing gate voltage. Taking into account both of these noise sources results in an optimum gate voltage value for the lowest displacement noise and hence best sensitivity. We show that a displacement sensitivity of about 10^-4 Angstroms and a force sensitivity of about 10^-16 N are predicted for a micron-sized cantilever with a realizable resonant frequency 100 MHz and quality factor Q~10^4. Such sensitivities would allow the detection of quantum squeezing in the mechanical motion of the micro-mechanical cantilever and the detection of single-spin magnetic resonance in magnetic resonance force microscopy (MRFM).
Nanoelectromechanical Systems
M. P. Blencowe
Physics , 2005, DOI: 10.1080/00107510500146865
Abstract: Nanoelectromechanical systems (NEMS) are nano-to-micrometer scale mechanical resonators coupled to electronic devices of similar dimensions. NEMS show promise for fast, ultrasensitive force microscopy and for deepening our understanding of how classical dynamics arises by approximation to quantum dynamics. This article begins with a survey of NEMS and then describes certain aspects of their classical dynamics. In particular, we show that for weak coupling the action of the electronic device on the mechanical resonator can be effectively that of a thermal bath, this despite the device being a driven, far-from-equilibrium system.
Universal quantum limits on single channel information, entropy and heat flow
Miles P. Blencowe,Vincenzo Vitelli
Physics , 2000, DOI: 10.1103/PhysRevA.62.052104
Abstract: We show that the recently discovered universal upper bound on the thermal conductance of a single channel comprising particles obeying arbitrary fractional statistics is in fact a consequence of a more general universal upper bound, involving the averaged entropy and energy currents of a single channel connecting heat reservoirs with arbitrary temperatures and chemical potentials. The latter upper bound in turn leads, via Holevo's theorem, to a universal (i.e., statistics independent) upper bound on the optimum capacity for classical information transmission down a single, wideband quantum channel.
Decoherence and Recoherence in a Vibrating RF SQUID
Eyal Buks,M. P. Blencowe
Physics , 2006, DOI: 10.1103/PhysRevB.74.174504
Abstract: We study an RF SQUID, in which a section of the loop is a freely suspended beam that is allowed to oscillate mechanically. The coupling between the RF SQUID and the mechanical resonator originates from the dependence of the total magnetic flux threading the loop on the displacement of the resonator. Motion of the latter affects the visibility of Rabi oscillations between the two lowest energy states of the RF SQUID. We address the feasibility of experimental observation of decoherence and recoherence, namely decay and rise of the visibility, in such a system.
Quantum analysis of a linear DC SQUID mechanical displacement detector
M. P. Blencowe,E. Buks
Physics , 2007, DOI: 10.1103/PhysRevB.76.014511
Abstract: We provide a quantum analysis of a DC SQUID mechanical displacement detector within the sub-critical Josephson current regime. A segment of the SQUID loop forms the mechanical resonator and motion of the latter is transduced inductively through changes in the flux threading the loop. Expressions are derived for the detector signal response and noise, which are used to evaluate the position and force detection sensitivity. We also investigate cooling of the mechanical resonator due to back reaction noise from the detector.
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