Accurate measurements of transition frequencies and isotope shifts of laser-trapped francium.

An interferometric method is used to improve the accuracy of the 7S-7P transition frequencies of three francium isotopes by 1 order of magnitude. The deduced isotope shifts for 209-211Fr confirm the ISOLDE data. The frequency of the D2 transition of 212Fr--the accepted reference for all Fr isotope shifts--is revised, and a significant difference with the ISOLDE value is found. Our results will be a benchmark for the accuracy of the theory of Fr energy levels, a necessary step to investigate fundamental symmetries.

Hyperfine Level Dependence of the Pressure Broadening of CH(3)I Rotational Transitions in the v(6) = 1 Vibrational State.

We studied the hyperfine components of the (J = 10-9, Kl = 9) rotational transition in the v(6) = 1 excited vibrational state of CH(3)I, using collinear infrared and mm-wave radiations. The Doppler-free double-resonance technique allowed an accurate determination of the collisional broadening parameters for all the hyperfine components. An evident dependence on the F quantum number was observed and this result is perfectly consistent with a theoretical model allowing calculations of collisional broadening and coupling for the hyperfine components. Copyright 2000 Academic Press.

The Molecular Constants of 12CH3I in the Ground and v6 = 1 Excited Vibrational State.

A set of 26 new measurements have been recorded by a Doppler-free double-resonance technique, with a relative accuracy of about 10(-8). These data are combined to previous FTIR measurements to refine the molecular constants of 12CH3I. All the available literature data have been revisited, a few assignments updated, and some frequencies changed according to new laser standards. A simultaneous fit to all the measurements of infrared, microwave, and radiofrequency transitions produced an improved set of parameters, independent of previously determined constants. Copyright 1998 Academic Press.

Discovering energy-transfer paths in laser crystals.

We demonstrate a new technique for discovering the main mechanisms of energy transfer inside the active crystal of a solid-state laser. It consists of measuring the harmonic content of fluorescence when the pump has a sinusoidal modulation. In particular we discuss excited-state absorption and upconversion and present the equations for the fundamental and the second harmonic for both of these processes. We measured the fluorescence from the (4)S(3/2) multiplet of Er(3+) in three hosts, YLF, YAG, and CaSGG, with different doping. The results of the new method show that we are able to identify which multiplets transfer their energy to the observed one and through which process.

[Comparative evaluation of 2 non-ionic contrast media, iopentol (350 mgI/ml) and iopamidol (370 mgI/ml) in coronary angiography]. / Valutazione comparativa di due mezzi di contrasto non ionici, iopentolo (350 mgI/ml) e iopamidolo (370 mgI/ml) in cardio-angiografia.

This randomized double-blind comparative study was designed to investigate the safety and efficacy of a new nonionic monomeric contrast agent, Iopentol 350 mgI/ml, versus a nonionic monomeric contrast agent currently used, Iopamidol 370 mgI/ml, in cardioangiography. Blood pressure, heart rate, end-diastolic left ventricular and mean aortic pressure, ECG, adverse reactions and discomfort were the safety variables recorded; technical adequacy and diagnostic yield were the efficacy variables recorded. A hundred patients entered the trial and were subdivided into two groups of 50 patients each; all of them were included in the safety and efficacy assessments. Demographic data, general and background characteristics and procedural data were comparable in the two treatment groups. No significant difference in efficacy was observed between the two groups: diagnostic yield was optimal in 90% of the patients in the Iopentol group and in 88% of the patients in the Iopamidol group. Systolic blood pressure 30 min. after the examination showed, in both groups, a slight but statistically significant reduction relative to baseline values (-3.48 mmHg and -3.85 mmHg in the Iopentol and in the Iopamidol group, respectively), while no significant reduction was observed in diastolic blood pressure. A statistically but not clinically significant decrease in heart rate was observed in the Iopamidol group 30 min. after the examination (-5.05%), while this variable remained practically the same in the Iopentol group (-0.58%). No difference was found between the two groups relative to the incidence of discomfort following the injection. Other adverse reactions were experienced by 7 patients in the Iopentol group and by 9 patients in the Iopamidol group: they all promptly recovered after medical treatment, with no sequelae. All but one event in the Iopamidol group (chest and abdominal pain with ECG changes) were mild to moderate and mainly related to the procedure and to the underlying disease. In conclusion, both contrast agents are safe and effective for use in cardioangiography.

Iomeprol vs iopamidol in intraarterial peripheral digital subtraction angiography.

The aim of this research was to compare the efficacy and tolerability of iomeprol, 150 mg iodine/mL, a new nonionic contrast medium, and iopamidol, 150 mg iodine/mg in intraarterial (IA) peripheral digital subtraction angiography (DSA) in 100 patients; a group of 40 patients were also submitted to a complete coagulation screening to check the influence of contrast media on blood clotting. The study was a comparative, double-blind clinical trial. The compound was assigned to each patient according to a randomization list. Small size (4-5 French) catheters were used in all patients to minimize arterial trauma and bedding time and to assess the quality of x-ray pictures in this condition. Vital signs, EKG tracings and laboratory parameters were monitored before and after the angiographic procedure; the coagulation screening included: thrombin time, prothrombin time, partial thromboplastin time, euglobulin lysis time, plasma thromboplastin antecedent, and plasminogen activator inhibitor (PAI). Both contrast media did not produce any adverse reaction or clinically significant alteration of studied parameters; in the 40-patient group subjected to massive coagulative screening, no important alteration after contrast media administration was reported. The score for contrastographic efficacy was very good with both media with a prevalence of better results in the iomeprol group.