Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET

The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutron emission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of a measured time-of-flight spectrum from TOFOR

On the mechanisms governing gas penetration into a tokamak plasma during a massive gas injection

A new 1D radial fluid code, IMAGINE, is used to simulate the penetration of gas into a tokamak plasma during a massive gas injection (MGI). The main result is that the gas is in general strongly braked as it reaches the plasma, due to mechanisms related to charge exchange and (to a smaller extent) recombination. As a result, only a fraction of the gas penetrates into the plasma. Also, a shock wave is created in the gas which propagates away from the plasma, braking and compressing the incoming gas. Simulation results are quantitatively consistent, at least in terms of orders of magnitude, with experimental data for a D 2 MGI into a JET Ohmic plasma. Simulations of MGI into the background plasma surrounding a runaway electron beam show that if the background electron density is too high, the gas may not penetrate, suggesting a possible explanation for the recent results of Reux et al in JET (2015 Nucl. Fusion 55 093013)

Relationship of edge localized mode burst times with divertor flux loop signal phase in JET

A phase relationship is identified between sequential edge localized modes (ELMs) occurrence times in a set of H-mode tokamak plasmas to the voltage measured in full flux azimuthal loops in the divertor region. We focus on plasmas in the Joint European Torus where a steady H-mode is sustained over several seconds, during which ELMs are observed in the Be II emission at the divertor. The ELMs analysed arise from intrinsic ELMing, in that there is no deliberate intent to control the ELMing process by external means. We use ELM timings derived from the Be II signal to perform direct time domain analysis of the full flux loop VLD2 and VLD3 signals, which provide a high cadence global measurement proportional to the voltage induced by changes in poloidal magnetic flux. Specifically, we examine how the time interval between pairs of successive ELMs is linked to the time-evolving phase of the full flux loop signals. Each ELM produces a clear early pulse in the full flux loop signals, whose peak time is used to condition our analysis. The arrival time of the following ELM, relative to this pulse, is found to fall into one of two categories: (i) prompt ELMs, which are directly paced by the initial response seen in the flux loop signals; and (ii) all other ELMs, which occur after the initial response of the full flux loop signals has decayed in amplitude. The times at which ELMs in category (ii) occur, relative to the first ELM of the pair, are clustered at times when the instantaneous phase of the full flux loop signal is close to its value at the time of the first ELM

Mannoside storage and axonal dystrophy in sensory neurones of swainsonine-treated rats: Morphogenesis of lesions

Young rats were treated with swainsonine for up to 200 days at a dose rate that restricted neuronal mannoside storage to neurones not protected by the blood/brain barrier. In lumbar dorsal root ganglion neurones, mannoside storage in the cell body developed in parallel to dystrophic changes at the extremities of peripherally and centrally directed axons. The dystrophic process involved the accumulation of autophagic structures. In the CNS, axonal dystrophy was confined to areas receiving long processes from affected neurones. The results suggest that axonal dystrophy is a direct consequence of the lysosomal storage process in parent cell bodies. The possible relationship of axonal dystrophy to neuronal lysosomal function is discussed

Nephrotic syndrome and collagenizing glomerulopathy in PVG/c rats treated with the α-mannosidase inhibitor "swainsonine"

Weanling PVG/c rats treated with the α-mannosidase inhibitor swainsonine developed increasing proteinuria which terminated as a severe nephrotic syndrome after 35 to 45 days. This was associated with a glomerulopathy characterized by the production of collagen fibrils adjacent to endothelial and mesangial cells, foot process expansion, subepithelial projections of the basement membrane, and splitting of the lamina densa. The swainsonine-induced glomerulopathy appeared to be an exacerbation of a spontaneous abnormality in this strain of rat

Identification of galegine, an isoprenyl guanidine, as the toxic principle of Schoenus asperocarpus (poison sedge)

An Isoprenyl guanldine, galegine, was isolated from the Western Australian sedge Schoenus asperocarpus (Cyperaceae). Synthetic galegine was shown to reproduce the clinical and pathological features of poisoning by this plant. Preliminary results suggest that the massive thoracic effusion observed in sedge poisoning is the result of a direct effect on pulmonary vascular permeability

The effect of age on biochemical and morphological changes in the semitendinosus muscle of cattle with generalized glycogenosis type II

Progressive changes in acid alpha-glucosidase activity, glycogen content and light microscopical and ultrastructural features in skeletal muscle of calves affected by generalized glycogenosis type II were assessed in biopsies from semitendinosus muscle of nine affected, twenty-six carrier and fifteen normal calves taken at varying times between birth and 17 months of age. Affected animals could be identified by using the PAS technique on paraffin and epon embedded material or by electron microscopy. However, estimation of acid alpha-glucosidase activity was required for precise diagnosis of generalized glycogenosis type II or to distinguish between normal and carrier animals. The glycogen content of the semitendinosus muscle of affected animals was approximately three times that in non-affected animals and although storage of glycogen reached a plateau soon after birth, the muscle fibre damage seen in very young calves increased with age. Morphological evidence of glycogen accumulation, both within the cytoplasm and within membrane bound structures, was present at birth. In some animals evidence of muscle fibre regeneration and damage was seen in the same sections

Dianellidin, stypandrol and dianellinone: An oxidation-related series from dianella revoluta

Dianellidin, stypandrol and dianellinone were isolated from Dianella revoluta and were considered with respect to their biosynthetic relationship and to the toxicity of Stypandra imbricata