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Biomedical subjects

B Erlandsson

Publications and source records attributed to B Erlandsson.

At least 19 recordsLinked to original sources
PubMed2004

Analysis of low-molar-mass materials in commercial rubber samples by Soxhlet and headspace extractions followed by GC-MS analysis.

Very tight regulations apply to materials used for pharmaceutical packaging and for administering drugs. In this paper, we describe a simple and reliable procedure involving both gas- and liquid-phase extraction steps followed by an analysis step to identify the low-molar-mass materials in commercial-rubber samples. Representative commercial rubbers, that could be used for pharmaceutical packaging, have been selected and cryogenically powdered. Headspace and Soxhlet extractions have been carried out and the key parameters are discussed. The obtained extracts have been analyzed by gas chromatography (GC)-mass spectrometry (MS). More than 100 compounds have been detected and identified. Headspace allowed to extract the more-volatile compounds, whereas Soxhlet extraction recovered less-volatile compounds, but induced a loss of the volatile ones. Thus, both extraction techniques are required to fully characterize the low-molar-mass compounds present in rubber.

Gas Chromatography-Mass Spectrometry↗
PubMed2003

Long-term study of 99Tc in the marine environment on the Swedish west coast.

The activity concentration of (99)Tc in brown seaweed (Fucus vesiculosus and Fucus serratus) and seawater were analysed in samples collected in 1991, 1995 and 2001 at several stations along the Swedish west coast. In addition to these locations, a well-defined site (Särdal, 56.76 degrees N, 12.63 degrees E) was included with (99)Tc activity concentration data in seaweed from 1967 to 2000. Over the years, the major source of (99)Tc in the coastal waters of western Sweden has been the radioactive liquid discharge from the nuclear fuel reprocessing plant in Sellafield (UK) transported via ocean currents in the North Sea. The (99)Tc activity concentration in seaweed at the Särdal site increased from approximately 30 Bq kg(-1) up to 230 Bq kg(-1) (dry weight) between 1997 and 2000 due to the Sellafield EARP (Enhanced Actinide Removal Plant) discharges in 1995-1996, yielding an approximate transport time of 4-5 years between the Irish Sea and the Kattegat. Due to the very sharp gradient in (99)Tc concentration between the Baltic Sea and the North Sea, (99)Tc is presently one of the best transit tracers for the recent ventilation events in the Baltic Sea.

Cesium Radioisotopes↗
PubMed2001

Observation of high-energy neutrinos using Cerenkov detectors embedded deep in Antarctic ice.

Neutrinos are elementary particles that carry no electric charge and have little mass. As they interact only weakly with other particles, they can penetrate enormous amounts of matter, and therefore have the potential to directly convey astrophysical information from the edge of the Universe and from deep inside the most cataclysmic high-energy regions. The neutrino's great penetrating power, however, also makes this particle difficult to detect. Underground detectors have observed low-energy neutrinos from the Sun and a nearby supernova, as well as neutrinos generated in the Earth's atmosphere. But the very low fluxes of high-energy neutrinos from cosmic sources can be observed only by much larger, expandable detectors in, for example, deep water or ice. Here we report the detection of upwardly propagating atmospheric neutrinos by the ice-based Antarctic muon and neutrino detector array (AMANDA). These results establish a technology with which to build a kilometre-scale neutrino observatory necessary for astrophysical observations.

Journal Article↗
PubMed2001

Studies of the radon concentration in drinking water from the horst Söderåsen in southern Sweden.

The radon activity concentration in ground water from drilled and dug wells on the horst Söderåsen in Southern Sweden has been determined with two different methods, gamma activity measurements with a germanium HPGe detector and alpha activity measurements with plastic track detectors. The results are consistent. High activity concentration is connected to granite bedrock. Dug wells have low concentrations and no trivial correlation between concentration and depth of the well is found. Large local variations exist. Activity concentrations > 700 Bq/l appear to be associated with leakage from layers of volcanic origin. The concentration from drilled wells is found to be quite constant over a 3 year period but short time variations appear to be significant. Evaporation from the open surface of a normal cooking vessel is slow with an activity gradient delta A/A of about 0.1-0.2 per hour at room temperature whereas even modest heating of water in e.g. a coffee machine is very efficient and reduces the radon activity concentration by > 90% in one process.

Radon↗
PubMed2001

A 10-year study of the 137Cs distribution in soil and a comparison of Cs soil inventory with precipitation-determined deposition.

During a 10-year period, 1988-1998, surface soil samples have been collected at Blentarp in southern Sweden and analysed for 137Cs from the Chernobyl accident and from the nuclear weapons tests. The distance between the sampling plots on the different sampling occasions has been no more than 3 m. The results show that the depth distribution of 137Cs is very similar for each of the sampling occasions, indicating that the caesium migration at this site is very small. The total activity measured in the soil cores is in agreement with the calculated activity of 137Cs deposited at the site after nuclear weapons tests and the Chernobyl accident, based on air activity concentration and the amount of precipitation. The calculated deposition of 137Cs originating from the bomb tests amounts to 1.41 kBq m-2 for the period 1962-1986, which is in agreement with the activity of nuclear weapons fallout measured in the soil samples (1.60 kBq m-2 as a mean value of the first four years of sampling). The calculated activity of 137Cs of Chernobyl origin was 0.79 kBq m-2, which agrees well with the value of 0.79 kBq m-2 measured in the soil samples in 1988.

Cesium Radioisotopes↗
PubMed1999

Biokinetics and radiation doses for carbon-14 urea in adults and children undergoing the Helicobacter pylori breath test.

The long-term biokinetics and dosimetry of carbon-14 were studied in nine adults and eight children undergoing carbon-14 urea breath test for Helicobacter pylori (HP) infection. The elimination of 14C via exhaled air and urine was measured with the liquid scintillation counting technique and with accelerator mass spectrometry. After the subjects had been given 110 kBq 14C-urea (children: 55 kBq) orally, samples of exhaled air were taken up to 180 days after administration and samples of urine were collected up to 40 days. Sixteen of the subjects were found to be HP-negative. In these subjects a total of 91.1%+/-3.9% (mean of adults and children +/- standard error of the mean) of the administered 14C activity was recovered. The majority of the administered activity, 88.3%+/-6.2% in adults and 87.7%+/-5.0% in children, was excreted via the urine within 72 h after administration. A smaller fraction was exhaled. In adults 4.6%+/-0.6% of the activity was exhaled within 20 days and in children 2.6%+/-0.3%. Uncertainties in the biokinetic results are mainly due to assumptions concerning endogenous CO2 production and urinary excretion rate and are estimated to be less than 30%. The absorbed dose to various organs and the effective dose were calculated using the ICRP model for urea and CO2. The urinary bladder received the highest absorbed dose: in adults, 0.15+/-0.01 mGy/MBq and in children of various ages (7-14 years), 0.14-0.36 mGy/MBq. The findings indicate that an investigation with 14C-urea gives an effective dose to adults of 2.1+/-0.1 microSv (for 110 kBq) and to children of 0.9-2.5 microSv (for 55 kBq). From a radiation protection point of view, there is thus no reason for restrictions on even repeated screening investigations with 14C-urea in whole families, including children.

Adolescent↗
PubMed1996

Application of accelerator mass spectrometry (AMS) for high-sensitivity measurements of 14CO2 in long-term studies of fat metabolism.

Long-term measurements of 14C in CO2 expired after ingestion of 14C-labelled triolein were performed using accelerator mass spectrometry (AMS). About 30% of a given amount of 14C-labelled triolein was catabolized rapidly, while the remaining 70% had a very slow turnover. The study shows the potential of the AMS technique for the study of the long-term biokinetics of 14C-labelled pharmaceuticals. The AMS technique allows the administered activity to be reduced by several orders of magnitude without compromising the study. It may also allow studies of rare drug metabolites.

Adult↗
PubMed1991

Seasonal variation of radionuclides in Fucus vesiculosus L. from the Oresund, Southern Sweden.

The activity concentrations of radionuclides (60Co, 54Mn, 137Cs, 40K) in whole plants of Fucus vesiculosus of different ages, and also in tissues of different ages from the same plants were investigated in the vicinity of the Barsebäck nuclear power plant in southern Sweden. Activity concentration differed between the tissues of different age of the plants, depending on the radionuclide as well as the time of year. The highest concentrations of 60Co and 54Mn were measured in the older parts of the plants in spring and summer, while the activity concentrations of 137Cs and 40K were highest in receptacles and new vegetative fronds. The discharge of radionuclides from the nuclear power plant was reflected in the measured activity concentration in the algae. For 60Co, the response seemed to be smoothed out when considering the whole plant, while the new vegetative tissue better reflected the discharge during the autumn. Thus, it is important to have knowledge about the autecology of the organism when it is used as an indicator for radionuclides.

Journal Article↗
PubMed1983

Hearing deterioration in shipyard workers. Serial audiometry over a four-year period.

The hearing thresholds of a total of 58 workers aged 20 to 65 years were measured annually over a period of 4 years using Békésy sweep-frequency audiometry. Using these data, accurate values of the yearly rate of change of hearing threshold level were calculated. The rate of change of hearing threshold level due to presbyacusis was obtained from several data sets, and the rate of change of hearing threshold level due to noise was calculated. When the average hearing threshold level over the frequency range 2-8 kHz was considered, it was found to be possible to establish a significant rate of threshold shift caused by exposure to noise for yearly changes as small as approximately 2 dB. In the cases investigated about 30% of the ears showed a significant deterioration in hearing ability due to noise. When comparing the permanent threshold shift caused by noise in groups of younger and older workers, it was found that the younger workers exhibited less threshold shift than expected, whereas the older workers showed a greater threshold shift than expected.

Adult↗
PubMed1980

Calculation of noise dose from time distribution of sound levels.

The noise from ten different sites in a machine factory was measured and cumulative time distributions of the sound pressure were constructed. From these distributions it is possible to calculate the energy mean level, the equivalent sound level as well as the average sound pressure level. Calculations based on knowledge of the times during which only a few sound pressure levels are exceeded give values deviating systematically from the exact value. Because of the systematic nature of the deviations corrections can be made for them. The accuracy of this method is relatively high.

Acoustics↗
PubMed1980

Noise dose measurements with stationary and ear-borne microphones.

Precision measurement of noise doses with stationary and mobile, ear-borne, microphones were made on ten workers (emery-grinders, welders and platers). The workers selected in each group differed from one another in the amount they moved about during their working day. The differences in the reverberant field at their working places were also taken into account. Very large noise dose differences, up to 20 dB, between stationary and mobile dose measurements were found and it was not possible to find any correction factors for these differences.

Acoustics↗
PubMed1980

The reliability of Békésy sweep audiometry recording and effects of the earphone position.

The hearing thresholds of subjects with hearing impairment of different severity were tested several times. The reliability of the hearing threshold measurements were analysed and compared to the inter-aural variations, the learning effects, the degree of noise-induced hearing impairment and the application of the earphones. The main factor determining the reliability of the hearing threshold is the application of the conventional earphone. A preliminary test-retest with the earphone adapted to an ear speculum for sound transmission to the external ear canal suggests that the precision of the Békésy sweep hearing threshold measurement can obviously be increased in the frequency range of 2 to 8 kHz.

Adult↗
PubMed1980

Hair cell damage in the guinea pig due to different kinds of noise.

Guinea pigs were exposed in groups of five animals to intense pure-tones or impulse noise, where either the intensity or the exposure duration was varied. The damage to the inner ear was analysed histologically and the loss of outer hair cells was used as damage parameter. The intensity in the pure-tone experimets was varied from 102 to 120 dB sound pressure level. The hair cell damage was not increasing proportionally over the entire intensity range. Above a certain critical level of intensity the damages started to increase more rapidly. This could be explained by theories stating that different mechanisms are responsible for the damage below and above the critical level. When the animals were exposed to impulse noise and the duration of the exposure was doubled the hair cell damage was also doubled up to an exposure time of 24 hours. At longer durations the increase of the damage seemed to level off. Animals exposed to impulse noise for 6 hours and with an equivalent sound level of 102 dB showed slightly higher mean damages than animals exposed to a corresponding continuous pure-tone. The results indicate that the total energy concept is a too simplified hypothesis concerning inner ear damage.

Age Factors↗
PubMed1980

The difference in protection efficiency between earplugs and earmuffs. An investigation performed at a workplace.

The hearing thresholds of shipyard workers have been measured with a Békésy sweep audiometer. The number of employees at different workplaces is so large that it is possible to select groups of workers of specified ages who have been employed by the shipyard for many years. These workers have used either earplugs of earmuffs for 5--10 years and have also been working all the time in almost the same noise environment. Three ways of investigation have been used to observe differences in the hearing levels between 'plug-men' and 'muff-men'. All three show a greater hearing impairment for 'muff-men' than for 'plug-men'. Under certain conditions earplugs provide the most effective protection although the attenuation is higher for earmuffs than for earplugs.

Adult↗