Demonstration of reduced neoclassical energy transport in Wendelstein 7-X.

Research on magnetic confinement of high-temperature plasmas has the ultimate goal of harnessing nuclear fusion for the production of electricity. Although the tokamak1 is the leading toroidal magnetic-confinement concept, it is not without shortcomings and the fusion community has therefore also pursued alternative concepts such as the stellarator. Unlike axisymmetric tokamaks, stellarators possess a three-dimensional (3D) magnetic field geometry. The availability of this additional dimension opens up an extensive configuration space for computational optimization of both the field geometry itself and the current-carrying coils that produce it. Such an optimization was undertaken in designing Wendelstein 7-X (W7-X)2, a large helical-axis advanced stellarator (HELIAS), which began operation in 2015 at Greifswald, Germany. A major drawback of 3D magnetic field geometry, however, is that it introduces a strong temperature dependence into the stellarator's non-turbulent 'neoclassical' energy transport. Indeed, such energy losses will become prohibitive in high-temperature reactor plasmas unless a strong reduction of the geometrical factor associated with this transport can be achieved; such a reduction was therefore a principal goal of the design of W7-X. In spite of the modest heating power currently available, W7-X has already been able to achieve high-temperature plasma conditions during its 2017 and 2018 experimental campaigns, producing record values of the fusion triple product for such stellarator plasmas3,4. The triple product of plasma density, ion temperature and energy confinement time is used in fusion research as a figure of merit, as it must attain a certain threshold value before net-energy-producing operation of a reactor becomes possible1,5. Here we demonstrate that such record values provide evidence for reduced neoclassical energy transport in W7-X, as the plasma profiles that produced these results could not have been obtained in stellarators lacking a comparably high level of neoclassical optimization.

Impact of Magnetic Field Configuration on Heat Transport in Stellarators and Heliotrons.

We assess the magnetic field configuration in modern fusion devices by comparing experiments with the same heating power, between a stellarator and a heliotron. The key role of turbulence is evident in the optimized stellarator, while neoclassical processes largely determine the transport in the heliotron device. Gyrokinetic simulations elucidate the underlying mechanisms promoting stronger ion scale turbulence in the stellarator. Similar plasma performances in these experiments suggests that neoclassical and turbulent transport should both be optimized in next step reactor designs.

Stellarators Resist Turbulent Transport on the Electron Larmor Scale.

Electron temperature gradient (ETG)-driven turbulence, despite its ultrafine scale, is thought to drive significant thermal losses in magnetic fusion devices-but what role does it play in stellarators? The first numerical simulations of ETG turbulence for the Wendelstein 7-X stellarator, together with power balance analysis from its initial experimental operation phase, suggest that the associated transport should be negligible compared to other channels. The effect, we argue, originates essentially from the geometric constraint of multiple field periods, a generic feature of stellarators.

Is ultraviolet exposure acquired at work the most important risk factor for cutaneous squamous cell carcinoma? Results of the population-based case-control study FB-181.

BACKGROUND: Squamous cell carcinoma (SCC) is one of the most frequent types of cancer constituting a significant public health burden. Prevention strategies focus on limiting ultraviolet (UV) exposure during leisure time. However, the relative impact of occupational and nonoccupational UV exposure for SCC occurrence is unclear. OBJECTIVES: To investigate the association between occupational and nonoccupational UV exposure for SCC in a multicentre population-based case-control study hypothesizing that high occupational UV exposure increases the risk of SCC. METHODS: Consecutive patients with incident SCC (n = 632) were recruited from a German national dermatology network. Population-based controls (n = 996) without history of skin cancer were recruited from corresponding residents' registration offices and propensity score matched to cases. Lifetime UV exposure, sociodemographic and clinical characteristics were assessed by trained physicians. Occupational and nonoccupational UV exposure doses were estimated by masked investigators using established reference values. Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were assessed using conditional logistic regression adjusting for relevant confounders. RESULTS: Total solar UV exposure was significantly associated with increased SCC. The OR for high (> 90th percentile) vs. low (< 40th percentile) and high vs, moderate (40-59th percentile) occupational UV exposure was 1·95 (95% CI 1·19-3·18) and 2·44 (95% CI 1·47-4·06) for SCC. Adjusting for occupational UV exposure, nonoccupational UV exposure was not significantly related to SCC incidence. Dose-response relationships were observed for occupational but not for nonoccupational solar UV exposure. CONCLUSIONS: Solar occupational UV exposure is a major determinant of incident SCC. Our findings indicate that prevention strategies should be further expanded to the occupational setting.

[A rare case of conductive hearing loss : Isolated fracture of the manubrium mallei as a consequence of digital manipulation in the external auditory meatus]. / Eine seltene Ursache für Schallleitungsschwerhörigkeit : Isolierte Fraktur des Manubrium mallei durch digitale Manipulation im Meatus acusticus externus.

Isolated fracture of the handle of the malleus is a rare cause of conductive hearing loss and represents a challenge for the otolaryngologist in terms of past medical history, diagnostics, and therapy.

Development of the 174 GHz collective Thomson scattering diagnostics at Wendelstein 7-X.

In this paper, we present the design and commissioning results of the upgraded collective Thomson scattering diagnostic at the Wendelstein 7-X stellarator. The diagnostic has a new radiometer designed to operate between the second and third harmonics of the electron cyclotron emission from the plasma at 171-177 GHz, where the emission background has a minimum and is of order 10-100 eV. It allows us to receive the scattered electromagnetic field with a significantly improved signal-to-noise ratio and extends the set of possible scattering geometries compared to the case of the original instrument operated at 140 GHz. The elements of the diagnostic are a narrowband notch filter and a frequency stabilized probing gyrotron that will allow measuring scattered radiation spectra very close to the probing frequency. Here, we characterize the microwave components applied to the radiometer and demonstrate the performance of the complete system that was achieved during the latest experimental campaign, OP2.1.

[Facial swelling caused by small cell lung cancer: a rare differential diagnosis of angioedema]. / Gesichtsschwellung bei kleinzelligem Bronchialkarzinom: Eine seltene Differenzialdiagnose des Angioödems.

Non-inflammatory swelling in the head and neck area are usually caused by allergic angioedema. However, other differential diagnoses must always be considered. Superior vena cava syndrome is a rare differential diagnosis of angioedema. Since we treated two such patients within only a few weeks of one another with the initial supposition of an ACE inhibitor-induced angioedema, but who ultimately proved to have lung cancer, we would like to draw attention to this disease pattern.

[The risks of autogenous cartilage grafting in laryngotracheal reconstruction in adults]. / Risiko des autogenen Knorpeltransplantats bei laryngotrachealer Rekonstruktion bei Erwachsenen.

BACKGROUND: Laryngotracheal reconstruction with autogenous rib cartilage graft has become a well established surgical method for the repair of subglottic and glottic laryngotracheal stenoses in infants and children. There are far fewer reports on the application of this method in adult patients. In particular, detailed observations of the healing behaviour of autogenous adult rib cartilage grafts are lacking. MATERIAL AND METHOD: The course of disease in five adult female patients (age 25-47 years) who underwent one- or two-stage laryngotracheal reconstruction with rib cartilage grafts are reported. RESULTS: Primary healing was observed in the youngest patient (25 years) only. In the other four patients the cartilage graft had to be partly removed 4-6 weeks postoperatively due to partial necrosis, followed by open wound treatment. As a result of these measures a sufficiently large laryngotracheal lumen could be achieved in all cases. DISCUSSION: Partial ossification of the adult rib cartilage was considered the reason for the observed healing difficulties. Endoscopic follow-up showed that epithelialization of the free endolaryngeal surface of the cartilage graft, i.e. graft healing, takes at least 3 months. Therefore, close endoscopic follow-up during this period appears indispensable.

Development of the ion cyclotron emission diagnostic for the W7-X stellarator.

An ion cyclotron emission (ICE) diagnostic is prepared for installation into the W7-X stellarator, with the aim to be operated in the 2022 experimental campaign. The design is based on the successful ICE diagnostic on the ASDEX Upgrade tokamak. The new diagnostic consists of four B-dot probes, mounted about 72° toroidally away (one module) from the neutral beam injector, with an unobstructed plasma view. Two of the B-dot probes are oriented parallel to the local magnetic field, aimed to detect fast magnetosonic waves. The remaining two probes are oriented poloidally, with the aim to detect slow waves. The radio frequency (RF) signals picked up by the probes are transferred via 50 Ω vacuum-compatible coaxial cables to RF detectors. Narrow band notch filters are used to protect the detectors from possible RF waves launched by the W7-X antenna. The signal will be sampled with a four-channel fast analog-to-digital converter with 14 bit depth and 1 GSample/s sampling rate. The diagnostic's phase-frequency characteristic is properly measured in order to allow measuring the wave vectors of the picked up waves.

[Closure of nasoseptal defects in Germany: the current state of the art]. / Nasenseptumdefektverschlüsse in Deutschland: Eine aktuelle Bestandsaufnahme.

OBJECTIVE: 20 years after its first description, the bridge-flap technique according to Schultz-Coulon has proven to be the most successful method by far for the closure of nasoseptal defects. The number of nasoseptal defects being treated in Germany, and the treatment methods being used, are currently an unknown factor. MATERIAL AND METHODS: A questioning survey was sent to all 157 German ENT clinics. They were asked about the number of treatments of nasoseptal defects and the frequency of surgical techniques applied during 2007. RESULTS: 123 questionnaires were evaluated (return ratio=78.3%). In total, 777 nasoseptal defects were treated in Germany during 2007. 31 clinics treated no nasoseptal defects; at 71 clinics, 1-10, at 16 clinics, 11-20, and at 5 clinics, more than 30 nasoseptal defects were treated. 713 nasoseptal defects (91.8%) received surgical treatment, and 64 (8.2%) were treated by inserting a silicone button. With 556 patients (78%), the surgical closures of the nasoseptal defects took place with the help of the bridge-flap technique. CONCLUSIONS: The survey data show a clear tendency towards the surgical care of nasoseptal defects at ENT clinics in Germany. In comparison to the previous school of thought that, in view of doubtful surgical results, symptomatic septal defects should be treated somewhat conservatively, a paradigm shift thereby took place. The fact that in the overwhelming majority of cases (78%), the bridge-flap technique according to Schultz-Coulon is used suggests that the favourable chances of success of this method are mainly responsible for the increasing surgical treatment of nasoseptal defects.

Forward modeling of collective Thomson scattering for Wendelstein 7-X plasmas: Electrostatic approximation.

In this paper, we present a method for numerical computation of collective Thomson scattering (CTS). We developed a forward model, eCTS, in the electrostatic approximation and benchmarked it against a full electromagnetic model. Differences between the electrostatic and the electromagnetic models are discussed. The sensitivity of the results to the ion temperature and the plasma composition is demonstrated. We integrated the model into the Bayesian data analysis framework Minerva and used it for the analysis of noisy synthetic data sets produced by a full electromagnetic model. It is shown that eCTS can be used for the inference of the bulk ion temperature. The model has been used to infer the bulk ion temperature from the first CTS measurements on Wendelstein 7-X.

Collective Thomson scattering diagnostic at Wendelstein 7-X.

A Collective Thomson Scattering (CTS) diagnostic is installed at Wendelstein 7-X for ion temperature measurements in the plasma core. The diagnostic utilizes 140 GHz gyrotrons usually used for electron cyclotron resonance heating (ECRH) as a source of probing radiation. The CTS diagnostic uses a quasi-optical transmission line covering a distance of over 40 m. The transmission line is shared between the ECRH system and the CTS diagnostic. Here we elaborate on the design, installation, and alignment of the CTS diagnostic and present the first measurements at Wendelstein 7-X.

[Surgical management of inverted papillomas of the nose and paranasal sinuses]. / Zum chirurgischen Behandlungskonzept bei invertierten Papillomen der Nase und Nasennebenhöhlen.

INTRODUCTION: Inverted papillomas require radical resection because of their high recurrence rate and expansive growth and the risk of malignant degeneration. Since the late 1980s surgical resection has been performed predominantly as an endoscopy-/microscopy-aided procedure through an endonasal approach. The extranasal approach is only used in the case of papillomas in unusual locations or ones that have expanded to an exceptional degree. The goal of the present study was a comparative evaluation of the results of this relatively new treatment strategy and of external sinus surgery in our own patients, with particular reference to the recurrence rate. PATIENTS AND METHODS: Since 1989 a total of 80 patients have undergone surgery for inverted papilloma and have been followed up at regular intervals by means of endoscopic examinations. In any patients with a recurrence the revision operation was carried out through an extranasal approach when the papilloma was in the anterior or laterocaudal maxillary sinus or in the frontal sinus; in all other cases an endonasal approach was used for the revision surgery. The mean period of follow-up was 43 months (range 15 months to 16years). RESULTS: In most patients (n=64, 80%) the endonasal surgical approach was used for the primary surgical treatment, while in 16 patients (20%) an extranasal approach was used initially. In 2 patients (2.6%) a squamous cell carcinoma was discovered adjacent to the papilloma. These two therapeutic special cases were not considered evaluable in the analysis of recurrences. Recurrences were seen in 14 patients (17.9%, n=78), in 11 patients after endonasal surgery (17.5%, n=11) and in 3 (20%, n=15) after extranasal resection. The majority of recurrences developed in patients with T3 papillomas. CONCLUSIONS: The recurrence rates observed after endonasal resection are comparable to those after extranasal surgery. Thus, a primary endonasal approach does not mean any prognostic disadvantage. This approach should therefore be given preference over extranasal approaches whenever possible, because there are fewer side-effects and recovery is faster than after extranasal surgery.

Absolute calibration of sniffer probes on Wendelstein 7-X.

Here we report the first measurements of the power levels of stray radiation in the vacuum vessel of Wendelstein 7-X using absolutely calibrated sniffer probes. The absolute calibration is achieved by using calibrated sources of stray radiation and the implicit measurement of the quality factor of the Wendelstein 7-X empty vacuum vessel. Normalized absolute calibration coefficients agree with the cross-calibration coefficients that are obtained by the direct measurements, indicating that the measured absolute calibration coefficients and stray radiation levels in the vessel are valid. Close to the launcher, the stray radiation in the empty vessel reaches power levels up to 340 kW/m(2) per MW injected beam power. Furthest away from the launcher, i.e., half a toroidal turn, still 90 kW/m(2) per MW injected beam power is measured.

Non-invasive screening of diabetes risk by assessing abnormalities of sudomotor function.

BACKGROUND: The early detection of diabetes, and subsequent lifestyle intervention, may reduce the burden of diabetes and its complications. Several studies have identified a link between sudomotor dysfunction, insulin resistance, and pre-diabetes. The aim of this study was to evaluate the ability of a new non-invasive device EZSCAN evaluating sudomotor function to detect pre-diabetes in a German population at risk for diabetes. METHODS AND FINDINGS: 200 German subjects at risk for diabetes (mean age 56±14 years, BMI 28.4±5.4 kg/m2) were measured for anthropometric data on inflammatory parameters, including high sensitivity C reactive protein (hs-CRP). The subjects also underwent an oral glucose tolerance test with measurements of plasma glucose, insulin, proinsulin, C-peptide and free fatty acids during 2 h following glucose challenge. Indexes for sensitivity to insulin were calculated: SI using minimal model, HOMA-IR and Matsuda index. Based on the measurement of electrochemical sweat conductance, subjects were classified as no risk, moderate risk or high risk. According to this risk model classification, a significant difference was observed between OGTT-1 h (p=0.004), AUC glucose (p=0.011), AUC C-peptide (p<0.001), HOMA-IR (p=0.009), Matsuda (p=0.002), SI (p<0.001) and hs-CRP (p=0.025) after adjustment for age. Among the 54 subjects with impaired fasting glucose or impaired glucose tolerance according to WHO classification, 37 had a moderate risk and 15 a high risk according to the EZSCAN risk model classification. Among the 12 subjects with newly diagnosed diabetes, 2 had a moderate risk and 10 a high risk according to the risk model classification. No adverse event was reported during or after the study. CONCLUSIONS: These results, in accordance with a previous study performed in India, show that EZSCAN could be developed as a screening tool for diabetes risk, and could help to improve diabetes screening strategies. Results obtained from an at-risk population would have to be confirmed in a larger population.

Immunoelectron microscopic single and double labelling of aminopeptidase N (CD 13) and dipeptidyl peptidase IV (CD 26).

Using ultrathin cryosections and immunogold labelling, aminopeptidase N (CD 13) and dipeptidyl peptidase IV (CD 26) were localized on the luminal side of the brush border membrane of proximal tubular cells in human kidney as well as of enterocytes from rat small intestine. Furthermore, both enzymes could be detected on the cell surface of human T lymphocytes and especially aminopeptidase N on human synovial fibroblasts. Gold labelled vesicular structures were also found in the cytoplasm in the apical part of renal proximal tubular cells and synovial fibroblasts. In human kidney the colocalization of the two membrane antigens was possible by using several double labelling methods.

Expression patterns of the ectopeptidases aminopeptidase N/CD13 and dipeptidyl peptidase IV/CD26: immunoultrastructural topographic localization on different types of cultured cells.

Aminopeptidase N/CD13 and dipeptidyl peptidase IV/CD26 are widespread membrane-bound peptidases involved in fundamental biological processes. Using cryo-ultramicrotomy of cultured cells followed by indirect immunogold labelling, both enzymes appeared to be strongly and regularly labelled on the cell surfaces of human synovial fibroblasts, T-lymphocytes and colon carcinoma cells Caco-2. In the cytoplasm of the synovial fibroblasts gold-labelled vesicle-like structures were found, which we consider to be potential transport vesicles. An abundant and regular expression of CD13 was detected on cultured renal parenchymal cells. On the renal carcinoma cell line Caki-1 cells we found a low, non-homogeneous and clustered CD13-labelling. On cultured renal parenchymal cells and the Caki-1 cells CD26 could not be observed. The expression pattern of CD26 on renal carcinoma cell line Caki-2 cells showed also a slightly clustered distribution. A low density CD26-labelling was present on the squamous cell carcinoma cell line UM-SCC-22B. CD13 was absent in Caki-2 and UM-SCC-22B cells. The presence of both enzymes on the cultured cells enables their ultrastructural investigation under different growth conditions and their involvement in cell-cell interactions. For this purpose, however, further investigations are necessary.

Immunoelectron microscopic demonstration of the membrane proteases aminopeptidase N/CD13 and dipeptidyl peptidase IV/CD26 in normal and neoplastic renal parenchymal tissues and cells.

Aminopeptidase N (APN, CD13) and dipeptidyl peptidase IV (DPP IV, CD26) are transmembrane ectoenzymes occurring in a wide variety of cells. They are involved in tumour cell invasion and the formation of metastases. A basis for further information about these enzymes is the exact ultrastructural localization in normal and malignant cells. In this paper, we demonstrate the precise subcellular localization of the membrane peptidases APN and DPP IV on the cell surfaces in renal tissues, renal cell carcinoma, cultured renal parenchymal cells and cultured renal carcinoma cells. Using cryo-ultramicrotomy of weakly fixed tissues and cells in combination with indirect immunogold labelling, both membrane peptidases were detectable on the external cell surfaces. They showed different ultrastructural expression patterns. Both membrane peptidases were abundantly labelled on the external cell surfaces of human kidney proximal tubular cells. The expression pattern of APN/CD13 and DPP IV/CD26 in single labelling was confirmed by a successive double labelling technique. The immunolabelling of CD13 on cultured renal parenchymal cells showed a stronger expression then in cells in vivo, but CD26 could not be found. In renal cell cancer (mixed clear cell/chromophilic, poorly differentiated and clear cell type, moderately differentiated) CD13 and CD26 were labelled as in benign renal tissue, but CD26 appeared overexpressed. On the renal carcinoma cells Caki-1 and Caki-2, only one of the two peptidases could be found. CD13 was present non-homogeneously in Caki-1, where the enzyme appeared to form clusters. When CD26 on the cultured renal carcinoma cells Caki-2, is compared with renal proximal tubular cells and renal carcinoma cells in tissue sections, a reduced expression is observed. CD13 was not detected in Caki-2, and CD26 was not found in Caki-1. These small changes on the cell surfaces can only be detected by electronmicroscopic methods. The differences in the distribution of APN/CD13 and DPP IV/CD26 in normal and malignant cells are discussed in connection with literature. Further investigations, especially labelling studies on other neoplastic tissues and cells, will be necessary in order to explain the precise role these membrane peptidases in malignancies.