Biomedical subjects
Publications and source records attributed to S Aubin.
We use two-photon resonant excitation and time-correlated single-photon counting techniques on a sample of 210Fr atoms confined and cooled in a magneto-optical trap to measure the lifetime of the 9s excited level. Direct measurement of the decay through the 7P(3/2) level at 851 nm yields a lifetime of 107.53 +/- 0.80 ns.
An algorithm for the daily localization of the prostate using implanted markers and a standard video-based electronic portal imaging device (V-EPID) has been tested. Prior to planning, three gold markers were implanted in the prostate of seven patients. The clinical images were acquired with a BeamViewPlus 2.1 V-EPID for each field during the normal course radiotherapy treatment and are used off-line to determine the ability of the automatic marker detection algorithm to adequately and consistently detect the markers. Clinical images were obtained with various dose levels from ranging 2.5 to 75 MU. The algorithm is based on marker attenuation characterization in the portal image and spatial distribution. A total of 1182 clinical images were taken. The results show an average efficiency of 93% for the markers detected individually and 85% for the group of markers. This algorithm accomplishes the detection and validation in 0.20-0.40 s. When the center of mass of the group of implanted markers is used, then all displacements can be corrected to within 1.0 mm in 84% of the cases and within 1.5 mm in 97% of cases. The standard video-based EPID tested provides excellent marker detection capability even with low dose levels. The V-EPID can be used successfully with radiopaque markers and the automatic detection algorithm to track and correct the daily setup deviations due to organ motions.
BACKGROUND: Computer-based teaching may allow effective teaching of important psychiatric knowledge and skills. AIMS: To investigate the effectiveness and acceptability of computer-based teaching. METHOD: A single-blind, randomized, controlled study of 166 undergraduate medical students at the University of Leeds, involving an educational intervention of either a structured lecture or a computer-based teaching package (both of equal duration). RESULTS: There was no difference in knowledge between the groups at baseline or immediately after teaching. Both groups made significant gains in knowledge after teaching. Students who attended the lecture rated their subjective knowledge and skills at a statistically significantly higher level than students who had used the computers. Students who had used the computer package scored higher on an objective measure of assessment skills. Students did not perceive the computer package to be as useful as the traditional lecture format, despite finding it easy to use and recommending its use to other students. CONCLUSIONS: Medical students rate themselves subjectively as learning less from computer-based as compared with lecture-based teaching. Objective measures suggest equivalence in knowledge acquisition and significantly greater skills acquisition for computer-based teaching.
Benzo[b]fluoranthene (B[b]F) was used in relative abundance ratios (RARs), a parameter obtained by dividing the concentration of individual polycyclic aromatic hydrocarbons (PAHs) found in a given sample by the concentration of B[b]F in the same sample. The B[b]F RARs were derived for PAH concentrations measured at stacks and sampling stations in the vicinity of two Söderberg aluminum horizontal stud smelters (HSSs). The samples collected were analyzed by high-performance liquid chromatography using UV and fluorescence detection. A total of 15 PAHs were analyzed, but, due to the inefficiency of the sampling method used in collecting gaseous PAHs, only particulate PAHs were considered. Comparisons between the B[b]F RARs obtained simultaneously at the source (stack) and those obtained at sampling stations at the two smelters showed that B[b]F degrades more slowly than or at the same rate as most other particulate PAHs monitored. Twenty-three months of urban sampling in the vicinity of one of the aluminum HSSs are also presented, and the results indicate that B[b]F is more stable than all other particulate PAHs investigated. Sampling conducted during a smelter shutdown period confirmed that B[b]F was a much better marker of this source than was benzo[a]pyrene (B[a]P), the usual indicator. The remarkable stability of the benzo[k]fluoranthene (B[k]F)/B[b]F ratio is also discussed.
We report a case of acute intoxication due to a massive overdose of isotretinoin. A 29-year-old male patient ingested 900 mg of isotretinoin corresponding to 12.5 mg (kg/day) or 30 times the prescribed dosage and 1 day later the patient experienced mild headache. Forty-eight hours later, cheilitis, diffuse cutaneous xerosis and desquamation of the forehead and of the external auditory meatus occurred; cutaneous xerosis and cheilitis resolved spontaneously, We determined the serum level of isotretinoin and of 4-oxo-isotretinoin, its natural metabolite in sera taken 4, 5, 6 and 11 days following ingestion. The side-effects were mild and represented only exacerbations of some common isotretinoin side-effects. To date, three other cases of isotretinoin overdosage have been reported. There was a low toxicity of isotretinoin overdose.
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In this article, the author proposes a behavioral evaluation model. The model takes into consideration both the resources and the limits of the person. This approach is employed with elderly persons who are considered to be < >. Their integration in reception centers poses many problems for helpers in those settings. In this project attention was paid to, among other subjects, attitudes toward the < > elderly person, the physical and human environment, and the training of personnel. The initial results show that it is possible to better integrate these persons and to improve their behavioral ability.