Broadening of the Divertor Heat Flux Profile in High Confinement Tokamak Fusion Plasmas with Edge Pedestals Limited by Turbulence in DIII-D.

Multimachine empirical scaling predicts an extremely narrow heat exhaust layer in future high magnetic field tokamaks, producing high power densities that require mitigation. In the experiments presented, the width of this exhaust layer is nearly doubled using actuators to increase turbulent transport in the plasma edge. This is achieved in low collisionality, high confinement edge pedestals with their gradients limited by turbulent transport instead of large-scale, coherent instabilities. The exhaust heat flux profile width and divertor leg diffusive spreading both double as a high frequency band of turbulent fluctuations propagating in the electron diamagnetic direction doubles in amplitude. The results are quantitatively reproduced in electromagnetic XGC particle-in-cell simulations which show the heat flux carried by electrons emerges to broaden the heat flux profile, directly supported by Langmuir probe measurements.

Calibration improvements expand filterscope diagnostic use.

The filterscope diagnostic on DIII-D utilizes photomultiplier tubes to measure visible light emission from the plasma. The system has undergone a substantial upgrade since previous attempts to cross-calibrate the filterscope with other spectroscopic diagnostics were unsuccessful. The optics now utilize a dichroic mirror to initially split the light at nearly 99% transmission or reflectance for light below or above 550 nm. This allows the system to measure Dα emission without degrading visible light emission from the plasma for wavelengths below 550 nm (to measure Dß, Dγ, W-I, C-III, etc.). Additional optimization of the optical components and calibration techniques reduce the error in the signal up to 10% in some channels compared to previous methods. Cross-calibration measurements with two other high resolution spectroscopic diagnostics now show excellent agreement for the first time. This expands the capabilities of the filterscope system allowing measurement of divertor detachment, emission profiles, edge-localized mode behavior, and plasma-wall interactions. It also enables direct comparisons against calculations from boundary plasma simulations. These were not possible before.

Robust Avoidance of Edge-Localized Modes alongside Gradient Formation in the Negative Triangularity Tokamak Edge.

In a series of high performance diverted discharges on DIII-D, we demonstrate that strong negative triangularity (NT) shaping robustly suppresses all edge-localized mode (ELM) activity over a wide range of plasma conditions: ⟨n⟩=0.1-1.5×10^{20} m^{-3}, P_{aux}=0-15 MW, and |B_{t}|=1-2.2 T, corresponding to P_{loss}/P_{LH08}∼8. The full dataset is consistent with the theoretical prediction that magnetic shear in the NT edge inhibits access to ELMing H-mode regimes; all experimental pressure profiles are found to be at or below the infinite-n ballooning stability limit. Our present dataset also features edge pressure gradients in strong NT that are closer to an H-mode than a typical L-mode plasma, supporting the consideration of NT for reactor design.

Improved Particle Confinement with Resonant Magnetic Perturbations in DIII-D Tokamak H-Mode Plasmas.

Experiments on the DIII-D tokamak have identified a novel regime in which applied resonant magnetic perturbations (RMPs) increase the particle confinement and overall performance. This Letter details a robust range of counter-current rotation over which RMPs cause this density pump-in effect for high confinement (H mode) plasmas. The pump in is shown to be caused by a reduction of the turbulent transport and to be correlated with a change in the sign of the induced neoclassical transport. This novel reversal of the RMP induced transport has the potential to significantly improve reactor relevant, three-dimensional magnetic confinement scenarios.

A 9-year analysis of transoral laser microsurgery (TLM) of head and neck cancer on their potential suitability for transoral robotic surgery (TORS) for estimation of future TORS-specific caseload.

OBJECTIVE: After that the establishment of transoral robotic surgery (TORS) for head and neck cancer has been adopted in North America, it has also recently been adopted in Europe. In these parts, transoral laser microsurgery (TLM) is widely applied. The aim of the study was to identify the absolute number of operations amenable to TORS at a TORS initiating institution on the basis of all former TLM cases. PATIENTS AND METHODS: All laser surgery procedures from May 2004 to April 2013 (108 months) were initially retrospectively registered; after that, all stage pT1 and pT2 squamous cell carcinomas of the oropharynx, hypopharynx, and larynx were selected. RESULTS: Over a period of nine years out of all TLM cases, there were 45 cases of pT1 and pT2 orohypopharyngeal and supraglottic squamous cell carcinomas, which could have been considered for TORS surgery. With the inclusion of a nowadays-typical TORS indication such as tonsil cancer, 142 cases would have been amendable to TORS. CONCLUSIONS: The indication for TORS would have been made in five of the TLM cases per year. Institutions initiating TORS, which own an intensive TLM experience, are encouraged to TORS indications in more than solely typical TLM indications. By indicating TORS instead of handheld surgery, a higher caseload of more than 15 cases per year can be achieved for TORS indications.

Three new extreme ultraviolet spectrometers on NSTX-U for impurity monitoring.

Three extreme ultraviolet (EUV) spectrometers have been mounted on the National Spherical Torus Experiment-Upgrade (NSTX-U). All three are flat-field grazing-incidence spectrometers and are dubbed X-ray and Extreme Ultraviolet Spectrometer (XEUS, 8-70 Å), Long-Wavelength Extreme Ultraviolet Spectrometer (LoWEUS, 190-440 Å), and Metal Monitor and Lithium Spectrometer Assembly (MonaLisa, 50-220 Å). XEUS and LoWEUS were previously implemented on NSTX to monitor impurities from low- to high-Z sources and to study impurity transport while MonaLisa is new and provides the system increased spectral coverage. The spectrometers will also be a critical diagnostic on the planned laser blow-off system for NSTX-U, which will be used for impurity edge and core ion transport studies, edge-transport code development, and benchmarking atomic physics codes.

Diagnostics for molybdenum and tungsten erosion and transport in NSTX-U.

A comprehensive set of spectroscopic diagnostics is planned in the National Spherical Torus Experiment Upgrade to connect measurements of molybdenum and tungsten divertor sources to scrape-off layer (SOL) and core impurity transport, supporting the installation of high-Z plasma facing components which is scheduled to begin with a row of molybdenum tiles. Imaging with narrow-bandpass interference filters and high-resolution spectroscopy will be coupled to estimate divertor impurity influxes. Vacuum ultraviolet and extreme ultraviolet spectrometers will allow connecting high-Z sources to SOL transport and core impurity content. The high-Z diagnostics suite complements the existing measurements for low-Z impurities (carbon and lithium), critical for the characterization of sputtering of high-Z materials.

A dual wavelength imaging system for plasma-surface interaction studies on the National Spherical Torus Experiment Upgrade.

A two-channel spectral imaging system based on a charge injection device radiation-hardened intensified camera was built for studies of plasma-surface interactions on divertor plasma facing components in the National Spherical Torus Experiment Upgrade (NSTX-U) tokamak. By means of commercially available mechanically referenced optical components, the two-wavelength setup images the light from the plasma, relayed by a fiber optic bundle, at two different wavelengths side-by-side on the same detector. Remotely controlled filter wheels are used for narrow bandpass and neutral density filters on each optical path allowing for simultaneous imaging of emission at wavelengths differing in brightness up to 3 orders of magnitude. Applications on NSTX-U will include the measurement of impurity influxes in the lower divertor strike point region and the imaging of plasma-material interaction on the head of the surface analysis probe MAPP (Material Analysis and Particle Probe). The diagnostic setup and initial results from its application on the lithium tokamak experiment are presented.

Flexible receiver for multiband orthogonal frequency division multiplexing signals at the millimeter waveband based on optical downconversion.

A novel (to our knowledge) and flexible photonics-based downconversion scheme is proposed for wireless receivers in base stations. It allows simultaneous detection of multiple signals at carriers up to tens of gigahertz, enabling communications at millimeter waves. Experiments demonstrate the effective downconversion of Wi-Fi signals at 2.4 and 39.8 GHz with the error vector magniture <-43 dB.

Spectral-domain OCT in anti-VEGF treatment of myopic choroidal neovascularization.

PURPOSE: To evaluate changes in macular morphology due to myopic choroidal neovascularization (CNV), using spectral-domain optical coherence tomography (SD-OCT). METHODS: In all, 22 eyes with recent-onset untreated CNV underwent 1 intravitreal injection of anti-vascular endothelial growth factor (anti-VEGF), followed by a pro-re-nata regimen. SD-OCT was performed at baseline (before first administration of anti-VEGF treatment) and month 1, and 2; macular morphologic changes and outer retina characteristics (SD-OCT findings) associated with CNV activity were evaluated. Sensitivity and specificity were calculated for SD-OCT findings using fluorescein angiography (FA) as standard reference. RESULTS: Mean central retinal thickness (CRT) showed no significant reduction from baseline (284±98 µm) to month 1 (257±74 µm) and month 2 (263±72 µm). A hyper-reflective lesion with fuzzy borders (fuzzy area), and 'absent or altered' IS/OS junction were the only SD-OCT findings associated with CNV activity (P<0.0001). Both these SD-OCT findings showed good sensitivity and specificity (95.1 and 96.0% (95% CI: 0.87-0.89), respectively, for the fuzzy area; 87.9 and 66.7% (95% CI: 0.65-0.87), respectively, for 'absent or altered' IS/OS junction) when compared with FA leakage (standard reference). CONCLUSIONS: Outer retina characteristics (ie, hyper-reflective lesion with fuzzy borders, and 'absent or altered' IS/OS junction) appear more meaningful than CRT in the evaluation of myopic CNV activity. These SD-OCT findings show overall good sensitivity and specificity when compared with FA leakage (standard reference), and could be considered as an alternative diagnostic tool to FA for myopic CNV monitoring.

[Ultrasound examination of the posterior ligament complex in thoracolumbar spinal fractures]. / Ultraschall zur beurteilung des posterioren ligamentkomplexes bei thorakolumbalen wirbelsäulenfrakturen.

BACKGROUND: thoracolumbar distraction injuries (AO classification type B) with damage to the posterior ligament complex (PLC) represent an indication for surgery but the use of X-ray and CT imaging often does not identify injuries of the PLC. The aim of this study was to evaluate the accuracy of ultrasound imaging in the assessment of the PLC status in thoracolumbar fractures of the spine. MATERIAL AND METHODS: in a prospective study the findings of the preoperative ultrasound examination were compared to the intraoperative findings. RESULTS: over a period of 2 years a total of 24 patients with 27 thoracolumbar fractures (18 type A, 9 type B) were examined. In 22 cases ultrasound examination was possible and correct ultrasound findings were made in 20 cases (91%). The sensitivity was 83.3%, specificity 93.8%, positive predictive value 83.3% and negative predictive value 93.8%. CONCLUSION: the use of ultrasound examination in thoracolumbar fractures is a suitable diagnostic tool for injuries of the posterior ligament complex in addition to radiological imaging.

[Type B injuries of the thoracolumbar spine : misinterpretations of the integrity of the posterior ligament complex using radiologic diagnostics]. / Typ-B-Distraktionsverletzungen der thorakolumbalen Wirbelsäule : Fehleinschätzungen des posterioren Ligamentkomplexes bei der radiologischen Diagnostik.

BACKGROUND: Type B injuries of the thoracolumbar spine (AO classification) indicate the need for surgical treatment. Type B1 injuries include disruption of the posterior ligament complex (PLC), which can be underdiagnosed when using x-ray and CT. The aims of this study were to determine the frequency of misclassification to compile similarities of type B1 injuries. MATERIALS AND METHODS: Retrospective study evaluating 361 fractures. RESULTS: Initially, 39 (41.9%) of 93 type B injuries were misdiagnosed as type A. 59% of 93 injuries belonged in the type B1 category. 29% of these showed no radiological signs of a PLC injury. Among the remaining cases, the following signs were the most frequently seen: vertebral segmental angle >15 degrees (44%), pronounced compression of vertebral cancellous bone despite minimal (<50%) reduced anterior vertebral height (41%), and a considerably reduced anterior vertebral height to <50% (31%). CONCLUSION: Type B injuries are frequently misinterpreted. To achieve a correct diagnosis, all clinical and radiological signs must be considered. 29% of all type B1 injuries cannot be detected on x-ray or CT scan.

Macular hole and intravitreal injection of triamcinolone acetonide for macular edema due to central retinal vein occlusion.

PURPOSE: To report a case of macular hole progression after intravitreal injection of triamcinolone acetonide (IVTA) for chronic macular edema secondary to nonischemic central retinal vein occlusion (CRVO). METHODS: A 33-year-old woman with massive macular edema after CRVO underwent IVTA. Optical coherence tomography (OCT) and fluorescein angiography were performed before and after the procedure. RESULTS: At the 1-week IVTA injection control, the patient's best-corrected visual acuity improved from 20/400 to 20/200 and OCT detected a progression of macular hole stage. CONCLUSIONS: IVTA steroid injection may provide a significant improvement in macular edema, but injection-related complications may occur such as this uncommon macular reaction resulting in permanent visual loss.

Ocular angiostrongyliasis in Japan: a case report.

A small motile worm was found in the posterior pole of the eye of a patient, producing a decrease in visual acuity. The patient had signs of meningitis and had cerebrospinal fluid eosinophilia. His serum was positive for antibodies to Angiostrongylus cantonensis. Without surgical intervention, the patient recovered and his visual acuity returned to normal.