Biomedical subjects

S Baradaran

Publications and source records attributed to S Baradaran.

4 recordsLinked to original sources

PubMed2006

Development of a high efficiency personal/environmental radon dosimeter using polycarbonate detectors.

Passive radon dosimeters, based on alpha particle etched track detectors, are widely used for the assessment of radon exposure. These methods are often applied in radon dosimetry for long periods of time. In this research work, we have developed a highly efficient method of personal/environmental radon dosimetry that is based upon the detection of alpha particles from radon daughters, (218)Po and (214)Po, using a polycarbonate detector (PC). The radon daughters are collected on the filter surface by passing a fixed flow of air through it and the PC detector, placed at a specified distance from the filter, is simultaneously exposed to alpha particles. After exposure, the latent tracks on the detector are made to appear by means of an electrochemical etching process; these are proportional to the radon dose. The air flow rate and the detector-filter distance are the major factors that can affect the performance of the dosimeter. The results obtained in our experimental investigations have shown that a distance of 1.5 cm between the detector and the filter, an absorber layer of Al with a thickness of 12 microm and an air flow rate of 4 l min(-1) offer the best design parameters for a high efficiency radon dosimeter. Then, the designed dosimeter was calibrated against different values of radon exposures and the obtained sensitivity was found to be 2.1 (tracks cm(-2)) (kBq h m(-3))(-1). The most important advantages of this method are that it is reliable, fast and convenient when used for radon dose assessment. In this paper, the optimized parameters of the dosimeter structure and its calibration procedure are presented and discussed.

Dose-Response Relationship, Radiation↗

PubMed2000

Bunk beds--a still underestimated risk for accidents in childhood?

UNLABELLED: A retrospective analysis of 218 bunk-bed accidents and a random sample survey with 991 family interviews were performed in order to establish guidelines for bunk-bed accident prevention. Falls from the top bed during sleep (35.1%) or while playing (34.4%) and falling off the ladder (23.2%) are the leading causes of bunk-bed accidents. Of the 218 children, 91 (41.7%) had sustained major injuries, including 3 polytrauma, 7 skull fractures, 44 cerebral concussions, 33 long bone fractures, 2 Lisfranc injuries, and 2 lacerations of the spleen. Of these accidents, 58.3% resulted in minor injuries with 18 fractures in other locations than the long bones or cranial vault, 89 contusions and sprains, 18 skin lacerations and 2 tooth fractures. A total of 23.8% of the accidents occurred in children under 3 years of age. The random sample survey demonstrated that in relation to age groups of children 30.8% (0%-45.8%) of families interviewed had been using bunk beds, with peaks at 3 years (29.8%), 7 years (36.5%) and 11 years (45.8%) of age. Of these bunk beds, 75.3% were equipped with side-rails, 57.3% had placed carpets alongside the bunk bed and 43.0% had used night lights. CONCLUSION: There is only one recommendation: no bunk beds!!!

Accidents↗

PubMed1995

[Spontaneous splenic rupture during portal triad clamping].

A 45-year-old woman underwent a resection for a hepatic metastasis of the liver caused by a carcinoma of the colon. Shortly after the Pringle maneuver severe hemorrhage from the upper left quadrant of the abdomen was observed. Exploration revealed a spontaneous parenchymal laceration of the spleen.

Colonic Neoplasms↗

PubMed1995

Periodontal files--a comparative study.

Periodontal files are used by many dentists for instrumentation of root surfaces as a part of periodontal treatment. The purposes of this study were: 1) to examine, evaluate, and compare several periodontal files in 3 different conditions: new, used, and used/sharpened and 2) to evaluate the efficacy of 5 sharpening devices. The main characteristics observed included: the number, shape, and interval of blades; the active, rake, and lip angles; changes induced by wear; the influence of sharpening; and the type of metal surfaces comprising the blades. There was a wide range of active angles on each individual file, from a high of 75 degrees to a low of 51 degrees. The range of active angles for all blades on all new files was even greater, from a high of 87 degrees to a low of 30 degrees. Wear, observed on some but not all blades, was not extensive and appeared either as abrasion or, occasionally, as fracture of the blade edge. Sharpness scores (5 = sharpest and 1 = dullest) for new file blades were also extremely variable and spanned the full range of values, with a majority of blades scoring 3.5 and below. Attempts to sharpen files with several devices produced inconsistent results. All 5 sharpening devices had significant shortcomings. It was concluded that the extreme ranges both in active angles and in sharpness scores probably have a significant influence on effectiveness of root instrumentation.

Dental Instruments↗