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At least 19 recordsLinked to original sources
PubMed1997

Measurement of radon decay products and thoron decay products in air by beta counting using end-window Geiger-Muller counter.

A new grab sampling method has been developed for the simultaneous measurement of radon decay products and thoron decay products in air. It is based on direct beta counting of filtered aerosol sample over successive time intervals by end-window Geiger-Muller counter. Defined solid angle absolute counting was used to evaluate the efficiencies for the decay products one by one. Absolute activity concentrations can be determined with less than 10% systematic error. Glass-fiber filter, high sampling flow rate, and long duration of sampling can be used, as a result of which the detection limits are about 0.1, 0.2, and 0.01 Bq m(-3) for 214Pb, 214Bi, and 212Pb, respectively. Indoor saturated activity concentrations were measured in 86 buildings in Ajka town, Hungary, where industrial wastes rich in uranium had been used as building materials. Elevated radon decay product levels were found in houses built before 1960. Radon gas concentration was also measured simultaneously in 26 cases and the minimum, maximum, and average values of the equilibrium factor were 0.17, 0.73, and 0.40, respectively.

Air Pollutants, Radioactive↗
PubMed2003

Results of surveys at United States pulp and paper mills for the presence of scales and precipitates containing naturally occurring radioactive material (NORM).

Field surveys were carried out at sixteen pulp and paper mills in the United States--seven kraft process, two sulfite process, and seven recycling process mills--for the presence of naturally occurring radioactive material (NORM) in precipitates and scales. NORM was detected at three of the kraft mills, one sulfite mill, and none of the recycling mills. At one of the kraft mills, the NORM was associated with a commercial aluminum sulfate ("alum") slurry used on the paper machines and in intake water treatment. The maximum activity level of this alum scale was 252,000 Bq kg(-1) (6,800 pCi g(-1)) 228Ra. At two kraft mills, NORM was associated with precipitates in the bleach plant. The measured NORM activity in samples of these scales was approximately 44,400 Bq kg(-1) (1,200 pCi g(-1)) 226Ra. Where NORM was detected at a sulfite mill, the NORM deposits were found adhering tightly to the surfaces of brownstock washers. Although samples were not removed for radionuclide analysis, survey readings at the drum surface were 26 nC kg(-1) h(-1) (100 microR h(-1)) with a scintillation counter and 2,200 cpm with a Geiger-Muller counter. At all mills, exposure rate measurements and risk assessment calculations indicated that it would be highly unlikely for any worker's annual exposure to exceed 1 mSv (100 mrem) (the Nuclear Regulatory Commission limit for untrained workers) due to exposure to these materials.

Background Radiation↗
PubMed1976

Cyclic condensed metaphosphates and linear polyphosphates in brown and red algae.

The occurrence of linear condensed polyphosphates and cyclic condensed metaphosphates was studied by means of pulse-labeling with 32P-orthophosphate (3--5h) in a number of Phaeophyceae species: Pylaiella litoralis, Ilea fascia, Ectocarpus siliculosus and also Rhodophyceae species: Ceramiumdeslongchampsii, C. rubrum, Rhodomela confervoides, Porphyridium purpureum and P. aerugineum. Two-dimensional cellulose thin layer chromatography revealed that in all species studied 32P-radioactivity was generally present in all oligopolyphosphates containing 2 to 7 phosphate residues, in cyclic metaphosphates (tri-, tetra-, penta- and hexametaphosphates) and in high-molecular-weight condensed phosphates which remained at the starting point. Among the low-molecular-weight condensed inorganic phosphates the trimetaphosphate had a significantly higher specific activity than the other oligophosphates which were separated on the chromatography plates as measured by the direct scanning with a Geiger-Muller counter. The phosphate uptake strongly depends on the internal pool of reserve phosphates of the algae cells. The 32P-orthophosphate incorporation of the cells is low and sluggish when growning in a synthetic medium or in sea water. Accordingly 32P appeared preferentially in the low-molecular-weight fractions of condensed phosphates since the storage phosphates were not yet used. After previous incubation in a P-free culture medium of the algae the 32P was rather rapidly incorporated and was found mostly in the high-molecular-weight condensed phosphates. During MAK-chromatography the high-molecular-weight fractions were eluted together with the nucleic acids (tRNA and DNA) while most of the low-molecular-weight fractions left the column immediately on elution.

Eukaryota↗
PubMed2001

Some case studies of skewed (and other ab-normal) data distributions arising in low-level environmental research.

Three general classes of skewed data distributions have been encountered in research on background radiation, chemical and radiochemical blanks, and low levels of 85Kr and 14C in the atmosphere and the cryosphere. The first class of skewed data can be considered to be theoretically, or fundamentally skewed. It is typified by the exponential distribution of inter-arrival times for nuclear counting events for a Poisson process. As part of a study of the nature of low-level (anti-coincidence) Geiger-Muller counter background radiation, tests were performed on the Poisson distribution of counts, the uniform distribution of arrival times, and the exponential distribution of inter-arrival times. The real laboratory system, of course, failed the (inter-arrival time) test--for very interesting reasons, linked to the physics of the measurement process. The second, computationally skewed, class relates to skewness induced by non-linear transformations. It is illustrated by non-linear concentration estimates from inverse calibration, and bivariate blank corrections for low-level 14C-12C aerosol data that led to highly asymmetric uncertainty intervals for the biomass carbon contribution to urban "soot". The third, environmentally, skewed, data class relates to a universal problem for the detection of excursions above blank or baseline levels: namely, the widespread occurrence of ab-normal distributions of environmental and laboratory blanks. This is illustrated by the search for fundamental factors that lurk behind skewed frequency distributions of sulfur laboratory blanks and 85Kr environmental baselines, and the application of robust statistical procedures for reliable detection decisions in the face of skewed isotopic carbon procedural blanks with few degrees of freedom.

Journal Article↗
PubMed1965

[Metabolism Of C(14)-Lactate By Fasciola Hepatica And Eurytrema Pancreaticum]

The adult trematode, Fasciola hepatica and Eurytrema pancreaticum, employed in this experiment were obtained from the cattle slaughtered at the local abbatoir. The worms were selected and washed several times in normal sterilized saline solution. Each ten of intact F. hepatica and about thirty to fifty of E. pancreaticum were incubated in 50 cc volume of special incubation flasks with incubation medium consisting of 50 cc of Krebs-Ringer phosohate buffer (pH 7.4). The incubation medium was added C(14)-lactate and non-radioactive carrier Na-lactate so as to contain lactate concentration of 32 mg per cent. The worms were allowed to incubate for 3 hours in the Dubnoff metabolic shaking incubator at 38 degrees C. After incubation period, respiratory CO2 samples from central wall of incubation flask were analysed for total CO2 production rate and their specific activity of respiratory CO2. The lactate uptake rate was determined by analyzing the the difference between lactate concentration in a medium before and after the incubation period, and the pyruvate appearance rate was dertermined by analyzing the pyruvate concentration in a medium after incubation. The glycogen samples isolated from worms were analyzed for the tissue concentration and their radioactivities in order to determine the turnover rate of glycogen pool. Radioactivities of these serise of experiment were counted by an endwindow Geiger-Muller counter as an infinitely thin samples. The quantative analysis of C(14)-lactate utilized by F. hepatica and E. pancreaticum were summerized and compared as following. In F. hepatica the lactate uptake rate was a mean value of 1.04 +/- 0.15 micro M/hr/g of wet wt. and pyruvate apperance rate was a mean value of 0.132 +/- 0.005 micro M/hr/g of wet wt. The total CO2 production rate by the flukes averaged 13.82 +/- 0.75 micro M/hr/g of wet wt. The relative specific activities of respiratory CO2 R.S.A(CO2) showed a mean value of 9.93 +/- 0.62 per cent. The rate of CO2 production derived from medium C(14)-lactate was a mean of 1.38 +/- 0.13 micro M/hr/g of wet wt. Therefore the averge value of 55.27 +/- 5.78 per cent (R.L.D(CO2)) and 15.35 +/- 1.90 per cent (R.L.D(pyr)) of lactate was oxidized into respiratory CO2 and pyruvate respectively. On the other hand, in E. pancreaticum the lactate uptake rate was a mean value of 0.61 +/- 0.18 micro M/hr/g of wet wt, and pyruvate appearance rate was a mean of 0.023 +/- 0.001 micro M/hr/g of wet wt. The total CO2 production rate by the E. pancreaticum averaged 4.29 +/- 0.85 micro M/hr/g of wet wt. The relative specific activity of respiratory CO2 (R.S.A(CO2)) showed a mean value of 9.20 +/- 0.34 per cent. Thus, a mean value of 9.20 per cent of total CO2 production rates was originated from C14-lactate in a medium, therefore the rate of CO2 production derived from medium C(14)-lactate was a mean value of 0.40 +/- 0.10 micro M/hr/g of wet wt. The average value of 23.93 +/- 7.11 per cent(R.L.D(CO2)) and 3.86 +/- 0.45 per cent(R.L.D(pyr)) of lactate was oxidized into respiratory CO2 and pyruvate respectively. The tissue concentration of glycogen in F. hepatica was a mean of 2.63 per cent/g of wet wt, while in E. pancreaticum was a mean of 4.06 per cent/g of wet wt. The turnover rate of glycogen pool in F. hepatica yielded a value of 0.073 +/- 0.008 micro M/hr/g of wet wt whereas in E. pancreaticum yielded only a mean of 0.006 +/- 0.002 mg/hr/g of wet wt. Therefore, the half time (t(2/1)) of glycogen turnover, which is the time interval required to replace the half of glycogen pool with medium C(14)-lactate, gave value of a mean of 10.73+/-0.76 days in F. hepatica. However, incorporation of C(14)-lactate into glycogen was negligible in the E. pancreaticum. Theses data impressed that the carbohydrate such as lactate may play a role of major part of their oxidative metabolism in F. hepatica, whereas minor part of lactate participates in the oxidative metabolism in E. pancreaticum.

Journal Article↗
PubMed1965

[Metabolism of C(14)-glucose by Paramphistomum cervi]

The trematode Paramphistomum cervi empolyed in this experiment was obtained from the reticulum of cattle slaughtered at the local abbatoir. The worms were selected and washed several times in normal sterilized saline solution. Each about ten of intact worms were incubated in 50 cc volume of special incubation flasks with incubation mixture consisting of 50 cc of Krebs-Ringer phosohate buffer (pH 7.4) to which were added universally labeled C(14)-glucose and non-radioactive carrier glucose concentration of 200 mg per cent. The worms were allowed to incubate for 3 hours in the incubator at 38 degrees C. After incubation period, respiratory CO2 samples from central wall of incubation flask were analysed for total CO2 production rate and their specific activity of respiratory CO2. Glycogen samples isolated from worms were analysed for the tissue concentration and their radioactivities in order to determine the turnover rate of glycogen pool. 1. The glucose uptake rate was determined by analysing the difference of the glucose concentration in a medium before and after incubation period. Radioactivities of these series of experiments were counted by an endwindow Geiger-Muller counter as an infinitely thin samples. The quantitative analysis of C(14)-glucose utilized by Paramphistomum cervi was summerized as the following. The glucose uptake rate by Paramphistomum was a mean value of 2.32 +/- 0.27 micro M/hr/g of wet wt. and total CO2 production rate by the worms averaged 10.85 +/- 0.41 micro M/hr/g of wet wt. The relative specific activities of respiratory CO2 averaged 49.72 +/- 13.20 per cent. Thus, a mean of 49.72 per cent of total CO2 production rate was originated from the glucose in the medium, therefore the rate of CO2 production derived from medium glucose was mean of 5.24 +/- 2.16 micro M/hr/g of wet wt. Thus, the average value of 37.46 +/- 5.28 per cent of glucose utilized by the worms from the medium glucose was oxidized to respiratory CO2. 2. The tissue concentration of Paraphismum was a mean of 41.56 +/- 5.82 micro M/hr/g of wet wt or 4.16 +/- 0.72 %/g, and the turnover rate of glycogen pool yielded with a mean of 0.12 +/- 0.014 %/hr or 0.06 +/- 0.04 mg/hr/g of wet wt. Therefore, a mean value of 16.75 +/- 4.84 per cent of glucose was incorporated to the glycogen. 3. These data account for that at least 54.21 per cent of the utilized glucose by the worms participated in furnishing the oxidation into respiratory CO2 and the synthetic process into glycogen. According to the above data of the experiment, it is suggested in the metabolic process of glucose by the Paramphistomum that the synthetic process into the glycogen is less active than the oxidative process into the resppiratory CO2.

Journal Article↗
PubMed1965

[Metabolism of C(14)-glucose by Ascaridia galli]

The fowl nematode Ascaridia galli employed in this experiment was obtained from the intestine of domestic fowls at the local market. The worms selected and washed several times in normal sterilized saline solution. Each about thirty of intact worms were incubated in 50 cc volume of special incubation flasks with incubation mixture consisting of 10 cc of Krebs-Ringer phosphate buffer (pH 7.4) to which were added universally labeled C14-glucose and non-radioactive carrier glucose so as to contain concentration of 200 mg per cent. The worms were allowed to incubation for 3 hours in Dubnoff metabolic shaking incubator at 38 degrees C. After incubation period, respiratory CO2 samples from central well of incubation flask were analysed for total CO2 production rate and their specific activity of respiratory CO2. Glycogen samples isolated from worms were analysed for uptake rate was determined by analyzing the difference of the glucose concentration in a medium before and after incubation period. Radioactivities of these series of experiments were counted by an endwindow Geiger-Muller counter as an infinitely thin samples. The quantitative analysis of C(14)-glucose utilized by Ascaridia galli was summarized as the following. 1. The glucose uptake rate by A. galli was a mean value of 1.73 +/- 0.32 micro M/hr/g of wet wt. and total CO2 production rate by the worms averaged 8.44 +/- 1.11 micro M/hr/g of wet wt. The relative specific activity of respiratory CO2 (R.S.A CO2) averaged 2.68 +/- 0.38 per cent. Thus, a man of 2.68 per cent of total CO2 production rate was originated from the glucose in the medium, therefore the rate of CO2 production derived from medium glucose was a mean of 0.23 +/- 0.03 micro M/hr/g of wet wt. Thus, the average value of 2.58 +/- 0.55 percent (R.G.D CO2)of glucose utilized by the worms from the medium glucose was oxidized to respiratory CO2. 2. The tissue concentration of glycogen in A. galli was a mean of 22.59 +/- 1.18 mg per gram of wet wt or 2.26 +/- 0.123 percent per gram, and the turnover rate of glycogen pool yielded with a mean of 0.17 +/- 0.04 percent per hour or 0.037 +/- 0.006 miligram per hour per gram of wet wt. Therefore, a mean value of 16.37 +/- 4.04 per cent (R.G.D gly) of glucose was incorporated to the glycogen. 3. These data account for that at least 18.95 per cent of the utilized glucose by the worms participated in furnishing the oxidation into respiratory CO2 and the synthetic process into glycogen. According to the above data of the experiment, it is suggested in the metabolic process of glucose by Ascaridia galli that the synthetic process into the glycogen is more active than the oxidative process into the respiratory CO2.

Journal Article↗
PubMed1965

[Metabolism of C(14)-acetate by some trematodes]

The adult trematodes, Fasciola hepatica, Eurytrema pancreaticum and Paramphistomum cervi, employed in this experiment were obtained from the cattle slaughtered at the local abbatoir. The worms selected and washed several times in normal sterilized saline solution. Each about ten of intact F. hepatica, fourty of E. pancreaticum, and twenty of P. cervi were incubated in 50 cc volume of special incubation flasks with incubation medium consisting of 10 cc. of Krebs-Ringer phosphate buffer(pH 7.4) The incubation medium was added C(14)-1-acetate and non-radioactive carrier Na-acetate so as to contain acetate concentration of 50 mg per cent. The worms were allowed to incubate for 5 hours in the Dubnoff metabolic shaking incubator at 38 degrees C. After incubation period, respiratory CO2 samples from central well of incubation flask were analysed for total CO2 production rate and their specific activity of respiratory CO2. The lactate and pyruvate appearance rates were determined by analyzing the lactate and pyruvate concentration in a medium after incubation. The glycogen samples isolated from worms were analyzed for the tissue concentration and their radioactivities in order to determine the turnover rate of glycogen pool. Radioactivities of these series of experiments were counted by an endwindow Geiger-Muller counter as an infinitely thin samples. The quantitative analysis of C(14)-acetate utilized by F. hepatica, E. pancreaticum and P. cervi were compared and discussed in this report. According to these data of the experiment, it is suggested that the fatty acid such as acetate may play a part of their oxidative process into the respiratory CO2 and the synthetic process into glycogen in the above species of trematodes.

Journal Article↗
PubMed1975

On the origin of desmethyl imipramine in rat brain.

The formation of DMI after incubation of IP-C-14 with supernatant fractions prepared from brain and liver of male Wistar rats were studied to determine the sources of DMI in brain tissue. IP and its metabolites were isolated by thin layer chromatography, eluted and counted in a Geiger-Muller counter. A substantial amount of DMI was formed when the liver supernatant fraction was used, whereas the brain fraction did not form DMI even at low level. Under the incubation condition used, about 2.7% of IP was converted non-enzymatically to a DMI-like substance. Based on the results presented it appears that at least most of the DMI reported by other authors to be formed in rat brain after IP administration, reaches the brain via the blood stream.

Animals↗
PubMed1992

Preparation of a 99mTc wipe standard for survey instrument calibration in nuclear medicine.

A method was developed for the preparation of a standard source to satisfy the U.S. Nuclear Regulatory Commission requirement for calibration of wipe-assay procedures used in nuclear medicine laboratories. An essential element of this standard was that a locally prepared calibration wipe could be used with thin-window Geiger-Muller detectors that detect 99mTc conversion electrons with high sensitivity. This proposed calibration wipe was evaluated with both a NaI(Tl) well counter and a thin-window Geiger-Muller pancake probe. Average detector sensitivities of 1,540 and 160 counts min-1 per 2000 disintegrations min-1, respectively, were found for 99mTc. An analysis of the errors for each step of the procedure showed most to be less than 3% (95% confidence level). The nuclear medicine dose calibrator, used to assay the activity from which the wipe was prepared, was estimated to contribute a 9% absolute calibration error. Use of the pancake probe contributed a 12% geometry-reproducibility error. The total error associated with the use of the calibration wipe standard to calibrate a typical 99mTc wipe-assay procedure, exclusive of the count-dependent error associated with the number of counts acquired, was found for the NaI(Tl) well counter to be given by a percentage of 2 SD = 10% and for the thin-window Geiger-Muller pancake probe, percentage 2 SD = 16%. Coating of the calibration wipe with an acrylic spray, to prevent it from contaminating instruments during use, was evaluated. This coating was effective while it reduced the detectability of the wipe activity by a negligible degree.

Calibration↗