30 research outputs found
Derivation of CPT resonance signals from density-matrix equations with all relevant sublevels of Cs atoms and confirmation of experimental results
Coherent-population-trapping resonance is a quantum interference effect that
appears in the two-photon transitions between the ground-state hyperfine levels
of alkali atoms and is often utilized in miniature clock devices. To
quantitatively understand and predict the performance of this phenomenon, it is
necessary to consider the transitions and relaxations between all hyperfine
Zeeman sublevels involved in the different excitation processes of the atom. In
this study, we constructed a computational multi-level atomic model of the
Liouville density-matrix equation for 32 Zeeman sublevels involved in the
line of Cs irradiated by two frequencies with circularly polarized
components and then simulated the amplitude and shape of the transmitted light
through a Cs vapor cell. We show that the numerical solutions of the equation
and analytical investigations adequately explain a variety of the
characteristics observed in the experiment.Comment: 24 pages, 8 figure
Serum levels of soluble Fas/APO-1 (CD95) and its molecular structure in patients with systemic lupus erythematosus (SLE) and other autoimmune diseases
There are two major forms of the Fas molecule, membranous Fas and soluble Fas (sFas). To clarify the clinical significance of sFas in autoimmune diseases, we designed a sandwich ELISA to determine serum concentrations of sFas and its molecular structure, and we then analysed the correlation between levels of sFas and laboratory findings in patients with SLE and other autoimmune diseases. The levels of serum sFas were significantly higher in SLE patients than in subjects with other autoimmune diseases and in healthy donors, and the frequency of a positive serum sFas was much greater in SLE patients with high SLE disease activity index scores than in those with low scores. In addition, sFas-positive SLE patients showed a significant difference in various laboratory parameters from sFas-negative SLE patients. Serial measurements of serum sFas levels in SLE patients with active disease revealed that the elevated level of sFas dramatically decreased with improvement in clinical and laboratory findings, following corticosteroid therapy. We propose that the serum level of sFas can serve as an appropriate marker for evaluating SLE disease activity. Serum sFas is heterogeneous with respect to molecular structure, thus several mechanisms are involved in the generation of sFas