Doppler coherence imaging and tomography of flows in tokamak plasmas (invited).

This article describes the results of spatial heterodyne Doppler "coherence imaging" of carbon ion flows in the divertor region of the DIII-D tokamak. Spatially encoded interferometric projections of doubly ionized carbon emission at 465 nm have been demodulated and tomographically inverted to obtain the spatial distribution of the carbon ion parallel flow and emissivity. The operating principles of the new instruments are described, and the link between measured properties and line integrals of the flow field are established. An iterative simultaneous arithmetic reconstruction procedure is applied to invert the interferometric phase shift projections, and the reconstructed parallel flow field amplitudes are found to be in reasonable agreement with UEDGE modeling.

Porous plug gas injection systems for studies of hydrocarbon dissociation and transport in the DIII-D tokamak.

A probe has been designed, constructed, and successfully used to inject methane into the DIII-D lower divertor in a manner imitating natural release by chemical erosion. This porous plug injector (PPI) probe consists of a self-contained gas reservoir with an integrated pressure gauge and a 3 cm diameter porous surface through which gas is injected into the lower divertor of the tokamak. The probe is positioned flush with the divertor target surface by means of the divertor materials evaluation system. Two gas delivery systems were developed: in the first, gas flow is regulated by a remotely controlled microvalve and in the second by a fixed micro-orifice flow restrictor. Because of the large area of the porous surface through which gas is admitted, the injected hydrocarbon molecules see a local carbon surface (>90% carbon) similar to that seen by hydrocarbons being emitted by chemical sputtering from surrounding carbon tiles. The distributed gas source also reduces the disturbance to the local plasma while providing sufficient signal for spectroscopic detection. In situ spectroscopic measurements with the PPI in DIII-D allow the direct calibration of response for measured plasma conditions from a known influx of gas.

Measurements of spatial line emission profiles in the main scrape-off layer of the DIII-D tokamak.

A video camera system is described as that measures the spatial distribution of visible line emission emitted from the main scrape-off layer (SOL) of plasmas in the DIII-D tokamak. A wide-angle lens installed on an equatorial port and an in-vessel mirror, which intercepts part of the lens' view, provide simultaneous tangential views of the SOL on the low-field and high-field sides of the plasma's equatorial plane. Tomographic reconstruction techniques are used to calculate the two-dimensional (2D) poloidal profiles from the raw data, and one-dimensional (1D) poloidal profiles simulating chordal views of other optical diagnostics from the 2D profiles. The 2D profiles can be compared with SOL plasma simulations; the 1D profiles with measurements from spectroscopic diagnostics. Sample results are presented, which elucidate carbon transport in plasmas with toroidally uniform injection of methane and argon transport in disruption mitigation experiments with massive gas jet injection.

Characterization by electrospray mass spectrometry of human Ca(2+)-sensitive cytosolic phospholipase A2 produced in baculovirus-infected insect cells.

The 85-kD cytosolic phospholipase A2 (cPLA2) is a novel receptor-regulated phospholipase that is thought to initiate the production of inflammatory lipid mediators. Since cPLA2 is present only in minute amounts (less than 0.01% of total cellular protein) in various cells and tissues, we have used the baculovirus expression system to produce sufficient quantities of cPLA2 for structural and functional analysis. The cDNA for cPLA2 was cloned into a baculovirus expression vector and, upon infection of Spodoptera frugiperda Sf-21 cells with the recombinant virus, cPLA2 was produced at high levels (9% of total cellular soluble protein). Gel electrophoresis and immunoblot analysis demonstrated that the recombinant protein has properties indistinguishable from cPLA2 present in human monocytic U937 cells. Structural analysis of recombinant cPLA2, using electrospray mass spectrometry in conjunction with automated sequence analysis, confirmed the expected sequence and revealed two post-translational modifications of the protein, phosphorylation on at least one site, and acetylation of the N-terminal serine residue after removal of the initiating methionine. In spite of the presence of six potential N-glycosylation sites, there is no evidence that any of them is glycosylated. The baculovirus expression system should prove useful for production of cPLA2, and electrospray mass spectrometry is a rapid and accurate method for the analysis of post-translational modifications.

Effect of body posture and time on grip strength in patients with cervical spondylosis.

Ninety-eight patients with cervical spondylosis were tested for grip strength in different spinal postures (standing and sitting), but with standard upper arm position. Unilateral symptoms of cervical spondylosis significantly affected grip strength in that arm whether or not it was the dominant upper limb, in contrast to normals. Grip strength is stronger in the standing position than in a sitting posture with the neck flexed (P < 0.01; at 10 min), and this effect is increased by duration in the posture.

Evaluation of amino acid analysis as reference method to quantitate highly purified proteins.

The applicability of amino acid analysis for accurate quantitation of reference standard preparations of proteins has been evaluated. This approach is very useful since, in addition to absolute quantitative information, it also provides a measure of composition, partial identity, and purity in a single experiment. Comparisons with Kjeldahl nitrogen assay and/or UV measurements shows that amino acid analysis is reliable for the quantitation of small-to-medium size proteins in the molecular weight range of 6-22 kDa. For larger proteins such as immunoglobulins (150 kDa), amino acid analysis may "underestimate" the total protein concentration. These results also show the effect of recovery of individual residues on protein quantitation. As expected, the recovery of more than one stable residue could be used to calculate total protein content of samples, which is in good agreement with the results obtained by Kjeldahl nitrogen assay. However, the protein concentrations calculated from the total mass of the recovered residues appear to give relatively low estimates in almost all cases. Thus, it is concluded that amino acid analysis is an appropriate reference method only when stable residues are employed for quantitation, particularly for highly purified proteins of rDNA origin.

A83586C, a new depsipeptide antibiotic.

A culture identified as Streptomyces karnatakensis was found to produce a novel cyclic hexadepsipeptide antibiotic designated A83586C. The structure was elucidated by X-ray crystallography, and full 1H and 13C NMR assignments are reported. The absolute configuration was confirmed by the detection of D-threonine in the acid hydrolysate of A83586C. A83586C had potent Gram-positive activity in vitro but lacked in vivo efficacy in mice.

High fibre diet in symptomatic diverticular disease of the colon.

Over the past decade fibre supplementation has achieved widespread acceptance in the management of symptomatic diverticular disease, although the efficacy of this treatment has been debated. We have conducted a retrospective review of 72 patients admitted to hospital with symptomatic diverticular disease over a ten year period in order to determine whether or not high fibre diet afforded protection against the development of complications, necessity for surgery or persistence of symptoms. Fifty-six patients were treated non-operatively, of these 43 received advice concerning a high fibre diet but only 31 patients complied. The 12 patients who failed to take additional fibre and the 13 patients who never received dietary advice (25 patients) formed the non high fibre group. Those treated with fibre supplementation fared significantly better in developing fewer complications and required less surgery (P less than 0.05). At the time of follow-up review patients on a high fibre diet reported significantly fewer symptoms (P less than 0.05).

Comparison of injection techniques for shoulder pain: results of a double blind, randomised study.

Seventy seven patients with soft tissue shoulder lesions including adhesive capsulitis and disorders of the rotator cuff and acromioclavicular joint were admitted to a trial comparing two different methods of corticosteroid injection with local anaesthetic in a randomly allocated double blind study. The method of anatomical injection after diagnosis by the technique of selective tissue tension gave 60% success compared with the method using tender or trigger point localisation, giving 20% success (p less than 0.001).

Single daily dose of allopurinol.

Allopurinol was administered to seven patients with gout to compare the effects of three different methods of administration. Allopurinol 100 mg given three times daily. Allopurinol given once daily as three 100 mg tablets. Allopurinol given once daily as a single 300 mg tablet. Allopurinol as a single dose in the morning gave as sustained control of plasma levels as did divided administration.