Mitral valve replacement via right thoracotomy approach for prevention of mediastinitis in a female patient with long-term uncontrolled diabetes mellitus: a case report

A 76-year-old woman with a history of percutaneous transvenous mitral commissurotomy and repeated hospital admissions due to heart failure was referred for an operation for severe mitral valve stenosis. She presented with hypertension, hyperlipidemia and cerebral infarction with stenosis of right internal carotid artery, retinopathy, neuropathy and nephropathy caused by long-term uncontrolled diabetes mellitus, hemoglobin A1c of 9.4%, and New York Heart Association (NYHA) functional classification of 3/4. Echocardiography revealed severe mitral valve stenosis with mitral valve area of 0.6 cm2, moderate tricuspid valve regurgitation, and dilatation of the left atrium. Taking into consideration the NYHA functional classification and severe mitral valve stenosis, an immediate surgical intervention designed to prevent mediastinitis was performed. The approach was via the right 4th thoracotomy, as conventional sternotomy would raise the risk of mediastinitis. Postoperative antibiotics were administered intravenously for 2 days, and signs of infection were not recognized

The Effect of Non-Axisymmetry of Magnetic Configurations on Radial Electric Field Transition Properties in the LHD

Transition property of the radial electric field (Er) in LHD have been theoretically investigated and also applied to explain experimental results. Especially, effects of the helicity of the magnetic configuration on the condition to realize the electron root are examined. Larger helicity makes the threshold collisionality higher. This is attributed to the nonlinear dependence of Γe(Er) in a low collisional regime. This interesting feature predicts that the threshold temperature becomes higher for a case of smaller helicity. The variation of the threshold density anticipated from the analysis for cases with different magnetic axis position is qualitatively verified in the density scan experiment

Droplet digital polymerase chain reaction assay and peptide nucleic acid-locked nucleic acid clamp method for RHOA mutation detection in angioimmunoblastic T-cell lymphoma

Angioimmunoblastic T‐cell lymphoma (AITL) is a subtype of nodal peripheral T‐cell lymphoma (PTCL). Somatic RHOA mutations, most frequently found at the hotspot site c.50G > T, p.Gly17Val (G17V RHOA mutation) are a genetic hallmark of AITL. Detection of the G17V RHOA mutations assists prompt and appropriate diagnosis of AITL. However, an optimal detection method for the G17V RHOA mutation remains to be elucidated. We compared the sensitivity and concordance of next‐generation sequencing (NGS), droplet digital PCR (ddPCR) and peptide nucleic acid‐locked nucleic acid (PNA‐LNA) clamp method for detecting the G17V RHOA mutation. G17V RHOA mutations were identified in 27 of 67 (40.3%) PTCL samples using NGS. ddPCR and PNA‐LNA clamp method both detected G17V mutations in 4 samples in addition to those detected with NGS (31 of 67, 46.3%). Additionally, variant allele frequencies with ddPCR and those with NGS showed high concordance (P T;50G > T], p.Gly17Leu in PTCL198; c.[50G > T;51A > C], p.Gly17Val in PTCL216; and c.50G > A, p.Gly17Glu in PTCL223) were detected using NGS. These sequence changes could not appropriately be detected using the ddPCR assay and the PNA‐LNA clamp method although both indicated that the samples might have mutations. In total, 34 out of 67 PTCL samples (50.7%) had RHOA mutations at the p.Gly17 position. In conclusion, our results suggested that a combination of ddPCR/PNA‐LNA clamp methods and NGS are best method to assist the diagnosis of AITL by detecting RHOA mutations at the p.Gly17 position

Impurity emission characteristics of long pulse discharges in Large Helical Device

Line spectra from intrinsic impurity ions have been monitored during the three kinds of long-pulse discharges (ICH, ECH, NBI). Constant emission from the iron impurity shows no preferential accumulation of iron ion during the long-pulse operations. Stable Doppler ion temperature has been also measured from Fe XX, C V and C III spectra

Improvement of Ion Confinement in Core Electron-Root Confinement (CERC) Plasmas in Large Helical Device

An increase in ion temperature has been observed with superposition of centrally focused electron cyclotron resonance heating (ECRH) to plasmas heated by high-energy neutral beam injection (NBI) in Large Helical Device. The ion-temperature (Ti) rise is accompanied by the formation of electron internal transport barrier (ITB). A transport analysis shows that ion transport as well as electron transport is improved with the reduction of anomalous transport. A neoclassical ambipolar flux calculation shows a positive radial-electric field (Er) in the region of the Ti rise, and Er should suppress the enhancement of ripple transport due to the Ti-rise. These analyses indicate the ion transport improvement in the core electron-root confinement plasmas. Toroidal rotation is driven in the co-direction by applying ECRH, and the toroidal rotation velocity is increased with the Ti rise. A correlation between the Ti rise and toroidal rotation is suggested

Recent Results from LHD Experiment with Emphasis on Relation to Theory from Experimentalist’s View

he Large Helical Device (LHD) has been extending an operational regime of net-current free plasmas towardsthe fusion relevant condition with taking advantage of a net current-free heliotron concept and employing a superconducting coil system. Heating capability has exceeded 10 MW and the central ion and electron temperatureshave reached 7 and 10 keV, respectively. The maximum value of β and pulse length have been extended to 3.2% and 150 s, respectively. Many encouraging physical findings have been obtained. Topics from recent experiments, which should be emphasized from the aspect of theoretical approaches, are reviewed. Those are (1) Prominent features in the inward shifted configuration, i.e., mitigation of an ideal interchange mode in the configuration with magnetic hill, and confinement improvement due to suppression of both anomalous and neoclassical transport, (2) Demonstration ofbifurcation of radial electric field and associated formation of an internal transport barrier, and (3) Dynamics of magnetic islands and clarification of the role of separatrix

Stability and Confinement Studies of High-Performance NBI Plasmas in the Large Helical Device Toward a Steady-State Helical Fusion Reactor

Recent progress in plasma performance and the understanding of the related physics in the Large Helical Device is overviewed. The volume-averaged beta value is increased with an increase in the neutral beam injection (NBI) heating power, and it reached 5.0% of the reactor-relevant value. In high-β plasmas, the plasma aspect ratio should be controlled so that the Shafranov shift would be reduced, mainly to suppress transport degradation and the deterioration of the NBI heating efficiency. The operational regime of a high-density plasma with an internal diffusion barrier (IDB) has been extended, and the IDB, which was originally found using the local island divertor, has been realized in the helical divertor configuration. The central density was recorded as high as 1 × 1021 m-3, and the central pressure reached 130 kPa. Based on these high-density plasmas with the IDB, a new ignition scenario has been proposed. This should be a scenario specific to the helical fusion reactor, in which the helical ripple transport would be mitigated. A low-energy positive-NBI system was newly installed for an increase in the direct ion heating power. As a result, the ion temperature (Ti) exceeded 5.2 keV at a density of 1.2 × 1019 m-3 in a hydrogen plasma. Transport analysis shows improvement of ion transport, and the Ti-increase tends to be accompanied by a large toroidal rotation velocity of the order of 50 km/s in the core region. The plasma properties in the extended operational regime are discussed from the perspective of a steady-state helical fusion reactor

Density Regimes of Complete Detachment and Serpens Mode in LHD

In the Large Helical Device (LHD), the hot plasma column shrinks at the high-density regime and complete detachment takes place. Hydrogen volume recombination is observed at complete detachment. This phase isself-sustained under specific experimental conditions and called the Serpens mode (self-regulated plasma edge ‘neath the last-closed-flux-surface). The Serpens mode is achieved after either rapid or slow density ramp up, and either by hydrogen or helium gas puffing. The threshold conditions for complete detachment and the Serpens mode are experimentally documented in the parameter space of heating power and density. The threshold density for the Serpens mode transition increases with ? 0.4 power of the heating power. The total radiation is shown to be not adequate to describe the threshold conditions, since it mainly includes the information of very edge region outside the hot plasma column. The operational density limit in LHD, which is sustainable in steady state, has been extended to 1.7 times as high as the Sudo density limit, by applying pellet injection to the Serpens plasmas