Peroperative manometric evaluation of posterior fundoplication by celioscopy

A severe allergic reaction to a porcelain-fused-to-metal fixed partial denture containing 79% palladium, 2% gold, and 19% copper, resulting in a variety of symptoms and hospitalization of the patient, is reported. The reaction occurred 4 hours after cementation of the fixed partial denture. Suggestions for use of nongold metal alloys are discussed.     

Signatures of Incoherence in a Quantum Information Processor

Incoherent noise is manifest in measurements of expectation values when the underlying ensemble evolves under a classical distribution of unitary processes. While many incoherent processes appear decoherent, there are important differences. The distribution functions underlying incoherent processes are either static or slowly varying with respect to control operations and so the errors introduced by these distributions are refocusable. The observation and control of incoherence in small Hilbert spaces is well known. Here we explore incoherence during an entangling operation, such as is relevant in quantum information processing. As expected, it is more difficult to separate incoherence and decoherence over such processes. However, by studying the fidelity decay under a cyclic entangling map we are able to identify distinctive experimental signatures of incoherence. This is demonstrated both through numerical simulations and experimentally in a three qubit nuclear magnetic resonance implementation.      

Experimental Concatenation of Quantum Error Correction with Decoupling

We experimentally explore the reduction of decoherence via concatenating quantum error correction (QEC) with decoupling in liquid-state NMR quantum information processing. Decoupling provides an efficient means of suppressing decoherence from noise sources with long correlation times, and then QEC can be used more profitably for the remaining noise sources. PACS: 03.67.Lx, 03.65.Bz     

Experimental Simulation of Spin Squeezing by Nuclear Magnetic Resonance

We report on the experimental simulation of spin squeezing using a liquid-state nuclear magnetic resonance (NMR) quantum information processor. This was done by identifying the energy levels within the symmetric subspace of a system of n spin-1/2 nuclei with the energy levels of the simulated spin-(n/2) system. The results obtained for our simulations of spin-1 and spin-3/2 systems are consistent with earlier theoretical studies of spin squeezing, and illustrate interesting relations between the degree of squeezing and the strength of the correlations among the underlying spin-1/2 particles.     

Laparoscopic myotomy for primary esophageal achalasia: prospective evaluation

BACKGROUND/AIM: The feasibility and safety of the laparoscopic myotomy having been previously demonstrated, the purpose of this prospective study was to evaluate its effectiveness. MATERIALS AND METHODS: Eight patients with primary esophageal achalasia underwent a laparoscopic modified Heller's myotomy with a posterior fundoplication. Early post-operative course has been uneventful in all cases. Clinical, endoscopic, and manometric prospective evaluations were performed with a median follow-up of 21 months (range 4-40). RESULTS: Excellent or good clinical results were present in all cases. Endoscopic studies were normal in all cases and the post-operative esophageal manometry (n = 7) showed that the median pressure of the lower esophageal sphincter decreased to 8.5 mmHg (range 3-9) which was significant compared to the median pre-operative value of 35 mmHg (p < 0.01). CONCLUSION: Though this experience is limited, these mean-term results suggest that the laparoscopic myotomy is effective to treat achalasia. It combines the efficacy of surgery and the minimally invasive aspect of dilatations. Thus, a prospective controlled trial comparing laparoscopic myotomy and dilatations is needed.     

Commissioning of the Iseult CEA 11.7 T whole-body MRI: current status,gradient–magnet interaction tests and first imaging experience

Objectives

The Iseult MRI is an actively shielded whole-body magnet providing a homogeneous and stable magnetic field of 11.7 T. After nearly 20 years of research and development, the magnet successfully reached its target field strength for the first time in 2019. This article reviews its commissioning status, the gradient–magnet interaction test results and first imaging experience.

Materials and methods

Vibration, acoustics, power deposition in the He bath, and field monitoring measurements were carried out. Magnet safety system was tested against outer magnetic perturbations, and calibrated to define a safe operation of the gradient coil. First measurements using parallel transmission were also performed on an ex-vivo brain to mitigate the RF field inhomogeneity effect.

Results

Acoustics measurements show promising results with sound pressure levels slightly above the enforced limits only at certain frequency intervals. Vibrations of the gradient coil revealed a linear trend with the B₀ field only in the worst case. Field monitoring revealed some resonances at some frequencies that are still under investigation.

Discussion

Gradient-magnet interaction tests at up to 11.7 T are concluded. The scanner is now kept permanently at field and the final calibrations are on-going to pave the road towards the first acquisitions on volunteers.