RESUMEN
We recently studied the spin-flipping efficiency of an rf-dipole magnet using a 120-MeV horizontally polarized proton beam stored in the Indiana University Cyclotron Facility Cooler Ring, which contained a nearly full Siberian snake. We flipped the spin by ramping the rf dipole's frequency through an rf-induced depolarizing resonance. By adiabatically turning on the rf dipole, we minimized the beam loss. After optimizing the frequency ramp parameters, we used 100 multiple spin flips to measure a spin-flip efficiency of 99.63+/-0.05%. This result indicates that spin flipping should be possible in very-high-energy polarized storage rings, where Siberian snakes are certainly needed and only dipole rf-flipper magnets are practical.
RESUMEN
UNLABELLED: Incidence of tuberculosis is sharply rising in the United States, and tuberculous peritonitis is often diagnosed late in the course of the disease, resulting in undue patient morbidity and mortality. PURPOSE: Purpose of this study was to better identify which clinical, laboratory, radiologic, and invasive procedures were most useful in diagnosing tuberculous peritonitis. METHODS: All cases of tuberculous peritonitis diagnosed between 1982 and 1994 were reviewed retrospectively to discern which laboratory, radiographic, and procedural tests were helpful in diagnosing the condition. RESULTS: Twenty-eight cases of tuberculous peritonitis were diagnosed during the studied period. Two patients were not diagnosed until autopsy. Patients from all socioeconomic classes and multiple races ranged in age from 3 to 69 (mean, 29.5) years. Most patients presented with a chronic wasting illness, mild abdominal pain, and fever. Purified protein derivative was only positive in 5 of 16 patients. Chest radiographs were suggestive of pulmonary tuberculosis (TB) in five patients. Ultrasound examination of the abdomen was helpful in five patients, and computed tomographic scan was suspicious in 16 of 17 patients. Sputum for acid fast bacillus (AFB) smear was positive in 3 of 14 patients, and paracentesis for AFB smear was positive in 1 of 8 patients. Routine blood work was not helpful. Laparoscopy was diagnostic in five of seven patients. Laparotomy and tissue biopsy of characteristic tissue for AFB smear and culture was diagnostic in 20 of 20 patients. Once diagnosed, all patients responded rapidly to empiric antituberculous medical therapy, except one patient with miliary TB who died shortly after diagnosis. A trend in earlier diagnosis was noted in recent years and is felt to be the result of an elevated index of suspicion. CONCLUSIONS: TB peritonitis may be fatal but is medically cured if diagnosed in a timely fashion. It is essential that the clinician suspect the disease in appropriate patients. Tests frequently associated with TB such as chest radiograph and purified protein derivative are not sensitive in detection of TB peritonitis. Computed tomographic scan is the most useful radiographic study. Mini laparotomy with tissue biopsy for smear and culture is the most sensitive and specific diagnostic procedure.