Development and first operation of a cavity ring down spectroscopy diagnostic in the negative ion source SPIDER

The neutral beam injectors of the ITER experiment will rely on negative ion sources to produce 16.7 MW beams of H/D particles accelerated at 1 MeV. The prototype of these sources was built and is currently operated in the SPIDER (Source for the Production of Ions of Deuterium Extracted from a Radio frequency plasma) experiment, part of the Neutral Beam Test Facility of Consorzio RFX, Padua. In the SPIDER, the H^-/D^- ion source is coupled to a three grid, 100 kV acceleration system. One of the main goals of the experimentation in SPIDER is to uniformly maximize the extracted current density; to achieve this, it is important to study the density of negative ions available in the proximity of the ion acceleration system. In SPIDER, line-integrated measurements of negative ion density are performed by a cavity ring down spectroscopy diagnostic. Its principle of operation is based on the absorption of the photons of a laser beam pulse by H^-/D^- photo-detachment; the absorption detection is enhanced by trapping the laser pulse in an optical cavity, containing the absorbing medium (i.e., negative ions). This paper presents and discusses the CRDS diagnostic setup in the SPIDER, including the first measurements of negative ion density, correlated with the main source parameters.

Fast Thermal Helium Beam diagnostic for measurements of edge electron profiles and fluctuations

The edge of fusion experiments is a region where strong gradients develop, together with the presence of strong fluctuations due to turbulence. The thermal helium beam diagnostic developed for the RFX-mod experiment allows the measurements with a single diagnostic of both low frequency time evolution of the edge radial profiles of electron density and temperature (tens of hertz), and the high frequency fluctuations (hundreds of kHz). To maximize the collected light, the three HeI lines necessary to be measured for the evaluation of n(e) and T(e) are separated with a spectrograph, and multianode photomultipliers are used as light detectors. The paper describes the diagnostic setup, with the interface hardware with the machine and the optical layout, and the characterization of its performances.

The effect of a new symbiotic formulation on plasma levels and peripheral blood mononuclear cell expression of some pro-inflammatory cytokines in patients with ulcerative colitis: a pilot study

BACKGROUND

During intestinal inflammation white blood cells are recruited from the blood, and they represent the major contributors to tissue perpetuation of inflammation via their production of chemokines and proinflammatory cytokines.

OBJECTIVES

Investigate the effect of a symbiotic formulation containing Lactobacillus Paracasei B 20160 versus placebo, on serum levels of interleukin (IL)-6, tumor necrosis factor (TNF)alpha, IL-8, IL-1beta and IL-10 and on mRNA lymphomonocyte expression of TNFalpha, IL-8 and IL-1beta in patients with ulcerative colitis.

MATERIALS AND METHODS

Eighteen patients entered the study with histologically proven not complicated ulcerative colitis, treated with mesalazine. Patients were treated for 8 weeks (9 with symbiotic and 9 with placebo). Serum levels of IL-6, TNFalpha, IL-8, IL-1beta and IL-10 were measured using a commercially available sandwich ELISA kit. RT-PCR analysis was performed on total RNA isolated from peripheral lymphomonocytes.

RESULTS

In basal condition, there was an increase of serum levels of TNFalpha, IL-6, and IL-8. The treatment with symbiotic significantly decreased serum levels of the last two cytokines (IL-6 and IL-8). In lymphocytes, the treatment with the symbiotic don't significantly reduced the mRNA expression of TNFalpha and IL-1beta, while that of IL-8 was strongly and significantly decreased.

CONCLUSION

Our preliminary results suggest that a symbiotic formulation containing Lactobacillus paracasei significantly improves the plasma and lymphocyte content of some proinflammatory cytokines.

Platelet aggregation is affected by nitrosothiols in patients with chronic hepatitis: In vivo and in vitro studies

AIM: To investigate the relationship among the number of platelets and plasma levels of S-nitrosothiols (S-NO), nitrite, total non-protein SH (NPSH), glutathione (GSH), cysteine (CYS), malondialdehyde (MDA), 4-hydroxininenal (4HNE), tumor necrosis factor-alpha (TNFα) and interleukin (IL)-6 in patients with chronic hepatitis C (CH).

METHODS: In vitro the aggregation of platelets derived from controls and CH patients was evaluated before and after the addition of adenosine diphosphate (ADP) and collagen, both in basal conditions and after incubation with nitrosoglutathione (GSNO).

RESULTS: In vivo, S-NO plasma levels increased significantly in CH patients and they were significantly directly correlated with platelet numbers. Patients with platelet counts < 150 000/μL, had a smaller increase in S-NO, lower levels of GSH, CYS, NPSH, TNFα, and IL-6, and higher levels of nitrite, MDA, and 4-HNE relative to those of patients with platelet counts > 150 000/μL. In vitro, the ADP and collagen aggregation time was increased in platelets from patients and not from controls; in addition, platelets from CH patients but not from controls also showed a latency time after exposure to collagen.

CONCLUSION: The incubation of platelets with GSNO improved the percentage aggregation and abolished the latency time.