Effects of target heating on experiments using Kα and Kß diagnostics.

We describe the impact of heating and ionization on emission from the target of Kα and Kß radiation induced by the propagation of hot electrons generated by laser-matter interaction. We consider copper as a test case and, starting from basic principles, we calculate the changes in emission wavelength, ionization cross section, and fluorescence yield as Cu is progressively ionized. We have finally considered the more realistic case when hot electrons have a distribution of energies with average energies of 50 and 500 keV (representative respectively of "shock ignition" and of "fast ignition" experiments) and in which the ions are distributed according to ionization equilibrium. In addition, by confronting our theoretical calculations with existing data, we demonstrate that this study offers a generic theoretical background for temperature diagnostics in laser-plasma interactions.

Inclusion of electric octupole contributions explains the fast radiative decays of two metastable states in Ar+.

A laser probing investigation has yielded the lifetimes of the 3s(2)3p(4)(1D)3d (2)G(7/2,9/2) metastable doublet states of Ar+. The results, obtained with the CRYRING ion storage ring of Stockholm, are 3.0+/-0.4 and 2.1+/-0.1 s, respectively. Comparisons with theoretical values calculated with two independent theoretical approaches, i.e., the pseudorelativistic Hartree-Fock method and the multiconfiguration Breit-Pauli approach, have allowed us to establish the unexpected and extraordinary strong contribution of an electric octupole (E3) transition to the ground state, in addition to the M1 decay channels to the 3d ;{2,4}F states and the E2 contributions to the 4s 2P, 2D states.

Importance of an M2 depopulating channel for a Kr II metastable state.

An experimental investigation of the radiative lifetime of the metastable 4s24p4(3P)4d4D7/2 level in Kr II shows an unusual situation regarding the importance of an M2 depopulation channel. While the first order M1 and E2 channels are expected to contribute in a dominant way to the decay, the experimental result, obtained using a laser probing technique on a stored ion beam, tau = 0.57+/-0.03 s, is far too short to be due to these channels according to our relativistic multiconfiguration Dirac-Fock calculation. Only if second order contributions to the decay branches (including essentially the M2 contribution) are taken into account in the calculations could the unexpected short lifetime be explained.

Time-resolved laser spectroscopy of multiply ionized atoms: natural radiative lifetimes in Ce IV.

Radiative lifetimes have been measured for two excited levels of Ce IV using the time-resolved laser-induced fluorescence technique. Ce3+ ions were produced in a laser-induced plasma. In the measurements, a suitable magnetic field was applied to reduce the recombination between electrons and the ions and thus the background light from the recombination, and special care was exercised to avoid flight-out-of-view effects on the lifetime measurements for the high-velocity ions. The experimental lifetime results, tau = 30(2) ns for the level 49 737 cm(-1) and tau = 30(3) ns for the level 52 226 cm(-1), were compared with relativistic Hartree-Fock calculations (tau = 30.5 and 30.0 ns) indicating a particularly excellent agreement.

Wolfram's syndrome and HLA.

A Sicilian family with three siblings affected by Wolfram's syndrome (Ws) is reported. HLA typing was performed in eight individuals from this family through three generations. Two of the three patients were HLA DR2 positive. The results suggest that the gene for Ws is not linked to the HLA region on chromosome 6, but located on some other chromosome, and that the allele HLA DR2 might predispose to the mutation responsible for Ws.

OKT4+ and OKT8+ cell subset values and HLA-DR phenotypes.

Blood levels of T cell subsets evaluated by use of monoclonal antibodies OKT4 and OKT8 were analyzed according to HLA-DR phenotypes. The results suggest that gene(s) associated with HLA-DR could be one of the factors which affects blood levels of T cell subsets, modulating the absolute values of T cell population.

HLA antigens in ulcerative colitis: a study in the Sicilian population.

HLA antigens were investigated in 41 Sicilian patients with ulcerative colitis and in 151 healthy controls. Frequencies of HLA-B5 and DR2 were increased in the group of patients with ulcerative colitis whereas the DR3 antigen frequency was decreased. However the corrected p values were not significant. Thus, present results indicate that in ulcerative colitis HLA linked genetic factors play a marginal role, if any.

HLA-DR phenotypes and blood levels of T cell subsets.

Blood mononuclear cell and T cell subsets values were analyzed in 53 Sicilian individuals according to HLA-DR phenotypes. The results demonstrate that DR1-positive subjects show a significant increase of blood T cell subsets whereas DR3-positive subjects show a non-significant decrease of these values. These results suggest that gene(s) associated with HLA-DR could be one of the factors which affect blood levels of T cell subsets.

Depression of contact sensitivity to oxazolone by the paramyxovirus of Newcastle disease. Impairment by infectious virus of effector T cells which mediate the response to contactant.

The paramyxovirus of Newcastle disease (NDV) impairs the contact sensitivity to oxazolone in CBA/J mice: in vitro treatment with the infectious virus inhibits the passive transfer of contact sensitivity. Experiments performed with three different virus preparations demonstrate that only the infectious virus is able to inhibit the hypersensitivity reaction while treatment of virus by heat or ultraviolet irradiation wipes out its inhibitory activity. These results suggest that I-NDV depresses the response to oxazolone by its action on T immunoblasts which mediate the response to contactant.

Effect of peptichemio upon localization of injected radiolabelled lymphocytes in the lymphatic organs of antigen-stimulated mice.

Increased localization (trapping) of lymphocytes occurs in lymphoid organs following antigenic challenge. The effect of peptichemio (PTC) upon lymphocyte trapping in lymph nodes and spleen was investigated: the results demonstrate that the drug diminishes trapping in lymphatic organs. The depression of lymphocyte trapping may provide at least one mechanism whereby PTC achieves it immunosuppressive effects.