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Biomedical subjects

F Steger

Publications and source records attributed to F Steger.

10 recordsLinked to original sources
PubMed2001

Results and conclusions of the Austrian radon mitigation project 'SARAH'.

The Austrian radon mitigation joint research project SARAH (supported by the Austrian Ministry of Economy and the Government of Upper Austria), a 2-year follow-up study of the Austrian National Radon Project (ONRAP), was started in 1996. The objectives of the research project were to find simple, cost-effective experimental methods for the characterisation of the radon situation in dwellings and to evaluate technically and economically the implementation of state of the art remedial actions for Austrian house types. After an intercomparison exercise of the assigned radon measuring instruments and detectors five houses were closely examined in regions with elevated radon levels in the federal state of Upper Austria. In this research work for the first time an extended Blower-Door method (which is conventionally used for determining the tightness of buildings) was successfully applied to radon diagnosis of buildings. In this paper the methods used for the radon diagnosis, the applied mitigation measures and the related technical and economical aspects are discussed. In conclusion of the results of this project a common strategy for solving the radon problem in Austria in the future is presented briefly.

Air Pollutants, Radioactive↗
PubMed2001

The long-term decrease of 90Sr availability in the environment and its transfer to man after a nuclear fallout.

Due to its long physical half-life, and the fact that its long-term mobility in the environment as well as its radiotoxicity is higher than that of 137Cs, the long-term bio-availability of 90Sr in the environment is of importance with regard to the long-term population exposure after fallout from nuclear weapons detonations or a severe reactor accident. It will also substantially influence the time-span required until re-utilisation of highly contaminated territory is possible again. An assessment of the long-term decrease of the activity concentration in all foodstuffs relevant for internal exposure after severe 90Sr fallout was performed. The observed effective half-lives were approximately 1.8-2.1 years in the first 2-3 years after the end of fallout and 8-10 years in the following three decades. This is equivalent to a biological half-life of about 13.2 years and results in a total 50 year dose of 6.2 times the first year exposure. Due to this decline in 90Sr-availability, the average annual activity intake of 90Sr in Austria has decreased from 840 Bq at the climax of the nuclear weapons tests to about 42 Bq in 1997 for adults, and from 500 Bq to about 35 Bq for 1 year old infants. This is equivalent to a 90Sr ingestion dose of 1.2 microSv for adults and 2.5 microSv for 1 year old infants in 1997 or less than 0.4% of the ingestion dose by natural radionuclides in the diet.

Air Pollutants, Radioactive↗
PubMed2001

[Daily medical practice in the Roman Empire from the patients perspective: P. Aelius Aristides, a patient of Asklepios in Pergamon].

While the perspectives of patients are generally included in the social history of medicine during the early modern period, patients' accounts are largely overlooked in the study of earlier periods. For students of antiquity the task is particularly arduous, since meaningful, self-reflexive legacies that could be used to examine the dimensions of patient history are rare. For instance, patient accounts from the period of the Roman Empire are scarce, and rather problematic primary sources. Devotions to the healing god Asklepios, his cult and his medicine incorporate patients' perspectives, but in most cases little useful information is gained from them. An additional source is the hieroi logi of P. Aelius Aristides, who was the patient of Asklepios in Pergamon for many years. These testaments have a fictional element that presents a methodological challenge to the historian. Nevertheless, as this article shows, answers to many questions relating to patient history can be extrapolated from Aristides' testaments.

History, Ancient↗
PubMed1998

Multifractal analysis of the 137Cs fallout pattern in Austria resulting from the Chernobyl accident.

The cumulative deposition of the 137Cs fallout in Austria resulting from the passage of the Chernobyl cloud has been investigated by applying correlation dimension and hyperbolic frequency distribution methods. For the analysis, a total of 1,881 deposition values were used, which were collected by the Federal Environmental Agency of Austria and the Federal Ministry of Health, representing all available measurements of 137Cs in soil made in Austria after the Chernobyl accident. From these data a hyperbolic exponent for the frequency distribution of 4.0 and a set of fractal correlation dimensions, which decrease from 1.426 +/- 0.022 (for the whole network) to 0.706 +/- 0.047 (for 137Cs values > or = 100 kBq m(-2)), were derived, thus confirming that the fallout pattern can be described as a multifractal.

Austria↗
PubMed1995

Occupational exposure and its effect on some immune parameters.

Some immunological parameters were investigated in a group of workers exposed to external radiation (1.4 to 9.8 mSv) and inhalation of tritium (comm. eff. dose equiv. 1.2 to 2.8 mSv). The present investigations indicate the differential radiosensitivity of lymphocytic subsets: CD8 positive suppressor T cells were found to be the most sensitive subpopulation in the peripheral blood of radiation exposed workers. CD4/CD8 ratios were increased mainly due to an increase in absolute numbers of CD4 positive helper T cells indicating a selective cell renewal after irradiation. Results obtained after phytohaemugglutinin stimulation of lymphocytes showed individual variation, though there seems to be a trend towards an inverse correlation between absolute T cell numbers in peripheral blood and the number of S phases observed after stimulation, low T cell numbers leading to a high rate of stimulation. The calculation of the committed effective dose equivalents show that radiation protection against internal tritium contamination in power plants should not be neglected.

Adult↗
PubMed1994

[Long-term integrated radon measurement on a small scale in Vienna and communication with the population].

Long-term integrated radon measurements (alpha-track) were carried out in two housing blocks in Vienna diagonally across from each other. The arithmetic mean was 41 becquerels/cubic metre (= Bq/m3), concentrations ranging from 157 to 9 Bq/m3. The largest variation found within one block came up to a factor of 13, within one house to a factor of 8 and within one floor of one and the same house to a factor of 4. The measurements gave the opportunity to practice risk communication with the residents of the two housing blocks.

Air Pollutants, Radioactive↗
PubMed1990

Estimate of the dose due to 90Sr to the Austrian population after the Chernobyl accident.

In order to estimate the contribution of 90Sr to the exposure of the Austrian population, the ratio of 90Sr to 137Cs in 126 food samples and nine drinking water samples was determined. From this and the average activity concentration of 137Cs in each type of food as obtained by the measurement of some 100,000 food samples after the Chernobyl accident, a good estimate of the average activity concentration of 90Sr in these food items could be obtained. Samples were investigated at various times after the accident to take into account possible changes with time in the 90Sr-activity concentration and its ratio to 137Cs. Also, pre-Chernobyl samples were measured to estimate the relative contribution of the reactor accident and the fallout of the atomic bomb testing to the intake of 90Sr. Assuming average food consumption, the intake of 90Sr for an adult person amounted to 168 Bq in the first year and 115 Bq in the second year after the accident, resulting in an effective dose equivalent of 5.9 muSv and 4.0 muSv, respectively. This is a minor fraction of the dose due to the ingestion of Cs isotopes, which amounted to 360 muSv in the first year and 97 muSv in the second year. For the one-year-old infant, a 90Sr intake of 96 Bq (10.5 muSv) in the first year and 65 Bq (7.1 muSv) in the second year is estimated. Approximately 50% of the intake in the first year and 70% of that in the second year are due to 90Sr from nuclear weapons testing.

Accidents↗
PubMed1989

[Exposure to radioactivity in the perinatal period following the reactor accident in Chernobyl].

After the Chernobyl nuclear accident on 26 April 1986 Europe experienced increased radioactive radiation by contamination of the atmospheric aerosol and the soil. Foods emanating radioactive radiation were ingested by the population to an increased extent via the food chain. This proportion of radioactive radiation accounted for about 80% of the total irradiation exposure and prompted us to examine mother's milk, amniotic fluid and placenta of newborn in respect of their concentrations of radionuclides I-131, Cs-134 and Cs-137. Due to the short half-life of I-131 an increased concentration of this substance was seen only during the first eight weeks after the nuclear accident. On the other hand, however, there was a clear increase in Cs-134 and Cs-137 from this time onward, the highest concentration of these two nuclides being measured only after one year after the accident. Despite the enhanced exposure to radioactivity of mother's milk and amniotic fluid, the guideline values laid down by Federal German legislation were not exceeded.

Accidents↗
PubMedDate not supplied

A ultra low level laboratory for nuclear test ban measurements.

The radionuclide laboratory at the Austrian Research Centers Seibersdorf (ATL03) was installed to support the international monitoring system for verification of the Comprehensive Nuclear-Test-Ban Treaty (CTBT and Text of the establishment of a Preparatory Commission for the Comprehensive Test-Ban-Treaty Organization, 1996). Therefore, the background of a high-purity germanium detection system has been reduced by developing a high sophisticated active and passive detector shielding. The entire system is encapsulated in an iron-castle and placed into a fall-out shelter. The final count rate, achieved over the energy interval from 40 to 2700 keV, amounts to 0.18 counts s(-1) kg(-1) (Ge).

Journal Article↗