Preparation, analysis, and application of coated glass targets for the Wendelstein 7-X laser blow-off system.

Coated glass targets are a key component of the Wendelstein 7-X laser blow-off system that is used for impurity transport studies. The preparation and analysis of these glass targets as well as their performance is examined in this paper. The glass targets have a high laser damage threshold and are coated via physical vapor deposition with µm thick films. In addition, nm-thin layers of Ti are used as an interface layer for improved ablation efficiency and reduced coating stress. Hence, the metallic or ceramic coating has a lateral homogeneity within 2% and contaminants less than 5%, being optimal for laser ablation processing. With this method, a short (few ms) and well defined pulse of impurities with about 1017 particles can be injected close to the last closed flux surface of Wendelstein 7-X. In particular, a significant amount of atoms with a velocity of about 1 km/s enters the plasma within 1 ms. The atoms are followed by a negligible concentration of slower clusters and macro-particles. This qualifies the use of the targets and applied laser settings for impurity transport studies with the laser blow-off system in Wendelstein 7-X.

Consequences of undetected olfactory loss for human chemosensory communication and well-being.

Olfactory perception has implications for human chemosensory communication and in a broader context, it affects well-being. However, most of the studies investigating the consequences of olfactory loss have recruited patients who have already been categorized as having a dysfunctional sense of smell and sought help in an ENT clinic. We revisit these findings by distinguishing subjects with olfactory impairment from a group of subjects who all declared a normal sense of smell when enrolling for this study. In the initial sample of 203 individuals, we found 59 to have impaired olfaction and four with marginal olfactory performance, not useful in daily life. Interestingly, we found a significant between-group difference in cognitive functioning, further supporting the notion of the relationship between cognition and olfactory performance. However, their chemosensory communication and well-being appeared not to be different from subjects with normosmia. Impaired olfactory function certainly has a severe impact on daily life but more so in individuals who are bothered with it and decide to seek treatment. The limited-to-no olfactory perception in the fraction of subjects who neither complain about it nor seek help in ENT clinics does not seem to have a major effect on their social, cognitive, emotional and health functioning. This article is part of the Theo Murphy meeting issue 'Olfactory communication in humans'.

Charge exchange recombination spectroscopy at Wendelstein 7-X.

The Charge Exchange Recombination Spectroscopy (CXRS) diagnostic has become a routine diagnostic on almost all major high temperature fusion experimental devices. For the optimized stellarator Wendelstein 7-X (W7-X), a highly flexible and extensive CXRS diagnostic has been built to provide high-resolution local measurements of several important plasma parameters using the recently commissioned neutral beam heating. This paper outlines the design specifics of the W7-X CXRS system and gives examples of the initial results obtained, including typical ion temperature profiles for several common heating scenarios, toroidal flow and radial electric field derived from velocity measurements, beam attenuation via beam emission spectra, and normalized impurity density profiles under some typical plasma conditions.

Plasma impurities observed by a pulse height analysis diagnostic during the divertor campaign of the Wendelstein 7-X stellarator.

The paper reports on the optimization process of the soft X-ray pulse height analyzer installed on the Wendelstein 7-X (W7-X) stellarator. It is a 3-channel system that records X-ray spectra in the range from 0.6 to 19.6 keV. X-ray spectra, with a temporal and spatial resolution of 100 ms and 2.5 cm (depending on selected slit sizes), respectively, are line integrated along a line-of-sight that crosses near to the plasma center. In the second W7-X operation phase with a carbon test divertor unit, light impurities, e.g., carbon and oxygen, were observed as well as mid- to high-Z elements, e.g., sulfur, chlorine, chromium, manganese, iron, and nickel. In addition, X-ray lines from several tracer elements have been observed after the laser blow-off injection of different impurities, e.g., silicon, titanium, and iron, and during discharges with prefill or a gas puff of neon or argon. These measurements were achieved by optimizing light absorber-foil selection, which defines the detected energy range, and remotely controlled pinhole size, which defines photon flux. The identification of X-ray lines was confirmed by other spectroscopic diagnostics, e.g., by the High-Efficiency XUV Overview Spectrometer, HEXOS, and high-resolution X-ray imaging spectrometer, HR-XIS.

Prospects of X-ray imaging spectrometers for impurity transport: Recent results from the stellarator Wendelstein 7-X (invited).

This paper reports on the design and the performance of the recently upgraded X-ray imaging spectrometer systems, X-ray imaging crystal spectrometer and high resolution X-ray imaging spectrometer, installed at the optimized stellarator Wendelstein 7-X. High resolution spectra of highly ionized, He-like Si, Ar, Ti, and Fe as well as H-like Ar have been observed. A cross comparison of ion and electron temperature profiles derived from a spectral fit and tomographic inversion of Ar and Fe spectra shows a reasonable match with both the spectrometers. The also measured impurity density profiles of Ar and Fe have peaked densities at radial positions that are in qualitative agreement with the expectations from the He-like impurity fractional abundances, given the measured temperature profiles. Repeated measurements of impurity decay times have been demonstrated with an accuracy of 1 ms via injection of non-recycling Ti, Fe, and Mo impurities using a laser blow-off system.

Design, capabilities, and first results of the new laser blow-off system on Wendelstein 7-X.

We present a detailed overview and first results of the new laser blow-off system on the stellarator Wendelstein 7-X. The system allows impurity transport studies by the repetitive and controlled injection of different tracer ions into the plasma edge. A Nd:YAG laser is used to ablate a thin metal film, coated on a glass plate, with a repetition rate of up to 20 Hz. A remote-controlled adjustable optical system allows the variation of the laser spot diameter and enables the spot positioning to non-ablated areas on the target between laser pulses. During first experiments, clear spectral lines from higher ionization stages of the tracer ions have been observed in the X-ray to the extreme ultraviolet spectral range. The temporal behavior of the measured emission allows the estimate of transport properties, e.g., impurity transport times in the order of 100 ms. Although the strong injection of impurities is well detectable, the global plasma parameters are barely changed.

Full automation of (68)Ga labelling of DOTA-peptides including cation exchange prepurification.

Here we describe a fully automated approach for the synthesis of (68)Ga-labelled DOTA-peptides based on pre-concentration and purification of the generator eluate by using a cation exchange-cartridge and its comparison with fully automated direct labelling applying fractionated elution. Pre-concentration of the eluate on a cation exchange cartridge both using a resin-based and a disposable cation-exchange cartridge efficiently removed (68)Ge as well as major metal contaminations with Fe and Zn. This resulted in a high labelling efficiency of DOTA-peptides at high specific activity (SA) with short synthesis times.

Structural and functional analysis of the S proteins of two human coronavirus OC43 strains adapted to growth in different cells.

The receptor-binding activity of strain CU (grown in MDCK I cells) and of strain VA (adapted to Vero cells) of human coronavirus OC43 was analyzed and compared with the binding activity of bovine coronavirus (BCV) and of the OC43 strain provided by the American Type Culture Collection (AT). Results obtained with resialylated erythrocytes indicated that the ability of the viruses to recognize 9-O-acetylated sialic acid in an alpha 2,6-linkage decreased in the following order: AT > CU > BCV > VA. Only minor differences were observed with respect to the alpha 2,3-linkage. The amino acid sequence of the S protein of strain CU and VA was derived from the nucleotide sequence of the cloned gene. Strain VA differed from strain CU in 34 positions, 18 in the S1 and 16 in the S2 subunit.

Structural and functional analysis of the surface protein of human coronavirus OC43.

The two surface glycoproteins S and HE of human coronavirus OC43 (HCV-OC43) were isolated from the viral membrane and purified. Only the S protein was able to agglutinate chicken erythrocytes, indicating that this viral protein is the major hemagglutinin of HCV-OC43. The receptor determinant recognized by this virus on the surface of erythrocytes is N-acetyl-9-O-acetylneuraminic acid (Neu5,9Ac2) which is also used by bovine coronavirus for attachment to cells. By analyzing erythrocytes containing different amounts of Neu5,9Ac2 in either of two linkage types, it was found that there are subtle differences in the affinity of both viruses for 9-O-acetylated sialic acid. Bovine coronavirus was more efficient in recognizing low amounts of Neu5,9Ac2 alpha 2,3 linked to galactose, whereas HCV-OC43 was superior with respect to the alpha 2,6 linkage. The gene coding for the S protein of HCV-OC43 was cloned and sequenced. A large open reading frame predicts a polypeptide of 150 kDa in the unglycosylated form. A protein of about 190 kDa is expected if the 20 potential glycosylation sites are used for attachment of N-linked oligosaccharide side chains. These predictions were confirmed by in vitro transcription and translation of the gene in the presence or absence of canine pancreatic microsomal membranes. A high degree of sequence homology was found between the S proteins of HCV-OC43 and bovine coronavirus. Structural and functional analyses of more strains should help to identify the location of the sialic acid-binding site.

Intraepidemic variants of influenza virus H3 hemagglutinin differing in the number of carbohydrate side chains.

During the epidemic outbreak in the region of Greifswald in the winter 1974/75, we found influenza virus variants which showed differences in the electrophoretic mobility of HA. Among the 25 isolates 13 were of slower and 12 of higher mobility. HA1 of 6 isolates was studied by determining the number of the carbohydrate side chains and by direct sequencing of vRNA. Evidence is presented that variants showing a slower electrophoretic mobility of HA1 had consistently acquired a seventh carbohydrate side chain at Asn 126 in epitope A. All the isolates differed from the reference strain A/Port Chalmers/1/73 by the loss of the oligosaccharide at Asn 81. The field strain A/Dresden/3/71 possessed only 5 oligosaccharides in HA1. These results suggest that changes in glycosylation are an important mechanism in the structural variation underlying antigenic drift of HA.

Foxglove tea poisoning.

Herbal teas occasionally produce toxic reactions. Unwitting use of the foxglove plant for brewing tea resulted in cardiac glycoside toxicity in an otherwise healthy man. Potentially toxic plants are omnipresent whereas herbal tea imbibing has had an enhanced popularity. Physicians will have increasing contact with patients who have inadvertently poisoned themselves with such concoctions.

Graded exercise testing in patients with sinus node dysfunction.

Serial measurements of heart rate and oxygen uptake were obtained before and during maximal upright graded bicycle stress testing in 16 patients, 10 to 77 years old (mean 46 years), with sinus node dysfunction; five had permanent and two had temporary demand ventricular pacemakers. In 15 patients, including those with pacemakers, maximal exercise was performed before and after the intravenous administration of 1 mg atropine. Maximal exercise was terminated because of cerebral symptoms in seven (three had effort-induced tachyarrhythmias and one had autonomic insufficiency), fatigue in five (one had effort-induced heart block), heart failure in three and angina pectoris in one. With maximal exercise, patients with sinus node dysfunction were unable to obtain maximal heart rates or oxygen uptakes comparable to age- and sex-matched control subjects. Additionally, maximal oxygen uptake did not differ significantly between patients with or without pacemakers even when ventricular pacing rates were increased (two instances). The administration of atropine increased the resting heart rate, but the maximal heart rate and oxygen uptake achieved during maximal exercise did not differ significantly from those obtained before the administration of atropine in the patient and control groups. Physically active patients with sinus node dysfunction have diminished exercise capacity due in part to cardiac arrhythmia, latent or overt cardiac failure, or autonomic dysfunction.

Atrial pacing in patients with sinus node dysfunction.

Sinus nod recovery time (SNRT) at paced atrial rates of 100 (SNRT100) and 120 (SNRT120) beats/min, atrial effective refractory periods at spontaneous heart rates (AERP) and at paced rates of 100 (AERP100) and 120 (AERP120) beats/min, and premature atrial stimulation were among the studies in evaluating 33 patients with symptomatic sinus node disease and 42 normal subjects. Although mean SNRT100 and SNRT120 were statistically significantly greater in patients than in control subjects, there was a significant overlap between patient and control groups, and SNRT100 or SNRT120 was associated with a 30.3 per cent false-negative and 5 per cent false-positive incidence. Correction for heart rate (SNRT-spontaneous cycle length) failed to improve the sensitivity or specificity of this test. There was no significant difference in mean AERP, AERP100 or AERP120, or in sinoatrial conduction time in patients compared with control subjects. Analyses of curves derived from plots of test and return cycles showed abnormal curves in only five of the 24 patients studied by progressively premature atrial stimulation. Two of these five patients showed normal zone I and II phenomena followed by a progressive linear increase in the return cycle that was thought to be due to abnormal refractoriness of the perinodal fibers.

Ankylosing spondylitis with complete heart block.

A patient with complete heart block due to ankylosing spondylitis exhibited an unusually brisk increase in ventricular rate with exercise. Despite broad ventricular (QRS) complexes, His bundle electrograms demonstrated a His deflection before each QRS complex and thus established the level of atrioventricular (A-V) block to be proximal to or localized to the His bundle. A junctional pacemaker accounted for the brisk response to exercise, atropine, or isoproteronol. Left bundle branch block pattern and prolongation of infranodal conduction time (H-Q) suggested additional disease involving the His bundle and/or right fascicle. Wide-spread disease affecting A-V nodal and infranodal conduction was compatible with pathologic changes seen in this disease. Because the pacemaker was able to respond to stress promptly and with appropriate increase in heart rate, the patient appeared not to warrant pacemaker implantation in his present state.