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A combination of experimental and numerical techniques revealed subtle features of oxygen absorption in unsparged stirred vessels. It was shown that the absorption kinetics was influenced not only by the mass transfer resistance in the gas-liquid interface but also by imperfect mixing in the bulk liquid. The liquid's viscosity and density were suggested to affect the oxygen mass transfer by influencing the turbulence both at the surface and in the bulk phase, while the modification of the surface layer through surfactant addition affected only surface turbulence. The axial dispersion model proved good in the explanation of the experimental results. For the sake of comparison, the classical stagnant film model was also tested but led to slight, yet systematic, deviations in its predictions from the experimental data. [ABSTRACT FROM AUTHOR]

The floating wire technique was applied to characterize the focusing properties of the D2 spectrometer magnet to be used in the ANKE installation of the COSY Ju¨lich accelerator facility. Trajectories corresponding to 140-600 MeV/c ejectiles emerging from a target in front of the rectangular-type D2 magnet were measured in order to determine the location of foci where detectors for the physics experiments were to be placed. The focus for trajectories of the same momentum was localized by varying the trajectory start angle at the target. To overcome the problem of instability, which arises when the pulley has to be located behind the focus, an unbalanced pulley was used. Other improvements include methodological features such as the particular design of our air-bearing pulley enabling a "freezing-in" of the wire movement and therefore yielding a very high accuracy of the wire position measurement, the use of a 40 μm gold-plated tungsten wire best fulfilling the mechanical and electrical requirements, a fast-regulating power supply in combination with an absolutely calibrated current meter, and the excellent accuracy of modern surveying instrumentation. An overall momentum accuracy of Δp/p<=10[sup -3] and a position accuracy of the trajectories of ±1 mm in the vicinity of the foci have been demonstrated. The precision and accuracy of the floating-wire measurements are discussed and compared with ray-tracing calculations based on measured and calculated field maps. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

To assess the disposition of the dihydropyridine calcium antagonist, nitrendipine, in lactating mothers, we studied three breast-feeding women to determine simultaneous plasma and breast milk concentrations of nitrendipine and its inactive pyridine analog metabolite after both a single 10 mg oral dose and 5 days of continuous therapy (20 mg per day). Nitrendipine was excreted in breast milk at peak concentrations ranging from 4.3 to 6.5 ng/ml 1-2 h after acute dosing while its inactive pyridine metabolite ranged from 6.9 to 11.9 ng·ml. After 5 days of dosing, C remained in the same range and the breast milk/whole plasma concentration ratio for nitrendipine was 0.2 to 0.5. On the fourth day of continuous dosing, average concentrations of nitrendipine from 24-h collections of the milk were 1.1 to 3.8 ng·ml. Thus, nitrendipine and its metabolite are excreted in very low concentrations in human breast milk. Based on a maternal dose of 20 mg daily, a newborn infant would ingest an average of 1.7 µg of nitrendipine per day, or a relative dose of 0.095%. [ABSTRACT FROM AUTHOR]

Photodynamic therapy (PDT) for treatment of head and neck cancer uses a photoactive compound that is illuminated with 630 nm (red) light. The effectiveness of PDT depends on the penetration of light into tissue that is both tissue and wavelength dependent. The characterization of the optical properties of an animal oral mucosa and skin has been done to determine the amount of light below these tissues available to be used for photodynamic therapy. The tissue absorbance of visible light from 400 nm to 700 nm has been determined in vitro for hamster check pouch mucosa and for athymic mouse skin. The pattern of absorbance is similar for both tissues and demonstrates greater transmission at the longer wavelengths. The diffuse transmittance of light in vivo for these animal models was measured with an interstitial fiberoptic probe. At 630 nm the diffuse transmittance for nude mouse skin averages 10% of the incident light energy, and that for the hamster mucosa almost 50% of the incident light energy. [ABSTRACT FROM AUTHOR]

Six patients with multifocal glioma are presented. Computerized tomography revealed multiple, discrete, contrast-enhancing lesions in the cerebral hemispheres, suggestive of multiple intracranial metastases. The most accessible lesion was resected at craniotomy in each patient, confirming the diagnosis of primary malignant glioma. Postoperative radiation therapy and chometherapy were instituted according to current protocols. Since neuroradiological studies may not allow distinction of multifocal gloima from multiple brain metastases, surgical biopsy is suggested in those patients who have no history of cancer. [ABSTRACT FROM AUTHOR]

Six biopsy proven cirrhotics and five age-matched controls (mean 55.3 vs 52.4 years) were randomly given single 60 mg p.o. and 30 mg s.l. doses of nimodipine. Serum concentrations and blood pressure were measured regularly over the subsequent 24 h period. The clearance of nimodipine was reduced in the patients with cirrhosis. Apparent oral clearance of nimodipine in the cirrhotic group was significantly lower than that observed in the normal group (187 +/- 163 l h-1 vs 469.6 +/- 198.4 l h-1, P less than 0.01). There were no significant changes in mean arterial pressure (MAP) in the normal subjects. There were, however, significant reductions in MAP following oral nimodipine in the cirrhotics. These reductions were significantly related to nimodipine concentrations in individual patients (P less than 0.05). [ABSTRACT FROM AUTHOR]

Functional magnetic resonance imaging (fMRI) in pediatric patients presents a unique set of problems due to the need for patient compliance, the frequent need for sedation and an early developmental status. A new method for using fMRI in sedated infants and young children is presented using passive stimuli focused on visual, sensorimotor and language functions. All of these stimuli are presented such that no patient interaction is required. Eight sedated children undergoing diagnostic MRI scans of the brain participated in these passive fMRI procedures. Cortical regions were identified using standard techniques applied to the blood-oxygen-level-dependent signal which is the basis for fMRI. The results support the feasibility of brain mapping in sedated children with passive fMRI techniques. [ABSTRACT FROM AUTHOR]

The level of CT section in the lumbosacral region may be correlated with routine AP views of the spine using a reference plane constructed according to the distance between the iliac crests. CT scans of the spine in 100 patients have been analyzed. The majority of these cases consisted of primary or secondary bone or soft-tissue tumors. CT examination was valuable to supplement plain films and/or myelograms in evaluation of the extent of pathology. It was also useful in the work-up of patients with malignant tumors whose other studies were equivocal. [ABSTRACT FROM AUTHOR]