Recent research findings of epidemiologist Alice Stewart suggest that nuclear workers may be at risk of contracting cancer even though their measured occupational doses fall within current safety standards. It is argued that these standards are inappropriate as they are based on extrapolations of studies on survivors of the Hiroshima and Nagasaki explosions. These individuals received single doses of radiation, whereas today's nuclear industry personnel are exposed to low-level ionizing radiation over the length of their working lives. Stewart's team linked low dose occupational exposure to ionizing radiation with an increased risk of cancer in respiratory, digestive and blood-forming tissues. The nuclear industry and United States government agencies hotly contest these assertion with their potentially damaging political and economic consequences. (UK).
Recent research findings of epidemiologist Alice Stewart suggest that nuclear workers may be at risk of contracting cancer even though their measured occupational doses fall within current safety standards. It is argued that these standards are inappropriate as they are based on extrapolations of studies on survivors of the Hiroshima and Nagasaki explosions. These individuals received single doses of radiation, whereas today's nuclear industry personnel are exposed to low-level ionizing radiation over the length of their working lives. Stewart's team linked low dose occupational exposure to ionizing radiation with an increased risk of cancer in respiratory, digestive and blood-forming tissues. The nuclear industry and United States government agencies hotly contest these assertion with their potentially damaging political and economic consequences. (UK).
With the exception of the 1945 Hiroshima and Nagasaki nuclear weapon explosions and the 1986 Tchernobyl reactor accident, most of the radiation accidents concerns the medical and the traditional industrial sectors. The seriousness of the accident is directly function of the absorbed dose. The paper, first, gives the definition of a radiologic accident with its specific criteria and pathological manifestations. Then, some famous historical accidents are reviewed from the discovery of X-rays to recent acute irradiations due to the careless manipulation of radiation sources. From this analysis, three main causes are put forward: the dysfunction of nuclear medicine apparatuses, the victims` lack of training and knowledge of the risks, and the non-identification or the loss of radiation sources. (J.S.). 1 photo.
Seizures are a frequent sequela of impaired brain development and can be expected to affect more children with radiation-related brain damage than children without such damage. This report deals with the incidence and type of seizures among survivors prenatally exposed to the atomic bombing of Hiroshima and Nagasaki, and their association with specific stages of prenatal development at the time of irradiation. Fetal radiation dose was assumed to be equal to the dose to the maternal uterus. Seizures here include all references in the clinical record to seizure, epilepsy, or convulsion. Histories of seizures were obtained at biennial routine clinical examinations starting at about the age of 2 years. These clinical records were used to classify seizures as febrile or unprovoked (without precipitating cause). No seizures were ascertained among subjects exposed 0-7 weeks after fertilization at doses higher than 0.10 Gy. The incidence of seizures was highest with ...
In the medical and occupational exposures, there is a tradition to use the genetically significant dose as an index of harm to the population although it only includes the genetical effects from ionizing radiations. A similar significant dose for somatic effects such as radiation leukemogenesis and carcinogenesis should be added to the genetically significant dose in order to approach an index of total harm to the population from medical and occupational exposures. For this purpose, leukemia and malignant significant factors were determined based on the induction of malignant diseases including leukemia for the atomic bombs in Hiroshima and Nagasaki and the life expectancy of individuals subject to medical examinations or treatments as well as radiation workers, taking account of the possibility of their deaths due to other diseases or accidents during a latent period of malignant diseases. The resultant significant factors ...
The atomic explosions in Hiroshima and Nagasaki made the name radiation itself become a nightmare. Notwithstanding this, radiation continued to serve the mankind specially in diagnosis of several human diseases and in the treatment of intractable malignancies. With their latest research tools biologists have now shown a significant shift in the earlier paradigm; even the concept that radiation initiates cancer appears to be no longer tenable. On the contrary, selective radiation doses inhibit growth of cancer cells and radiation in combination with many chemotherapeutic drugs, radiosensitizing chemicals and/or hyperthermia, is emerging as a new modality for cancer treatment which offers high therapeutic advantages. In addition, the deleterious effects of radiation can now be strategically counter poised by the use of many drugs and chemicals. This has been possible by the newer insights gained in the mechanism of biological effects of radiation. The fate of ...
Measuring gene expression using microarrays is relevant to many areas of biology and medicine, such as follow up of developmental stages and diseases onset, and treatment study. Since there can be tens of thousands of distinct probes on an array, each micro array experiment can accomplish the equivalent number of genetic tests in parallel. Arrays have therefore dramatically accelerated many types of investigations. For example, microarrays can be used to identify stress response genes by comparing gene expression in challenged versus normal cells. In the Molecular and Cellular Biology lab (MCB), the micro array experiments are performed within the Genomic Platform, fully equipped to analyse either the behaviour of bacteria during long space flight, the effect of low dose ionising radiation on the developing organism in mice, or the human individual radiation sensitivity. For the low dose effect, two main stages of development are of interest; 1) the gastrula stage at which ionizing ...
A Task Group of the International Commission on Radiological Protection (ICRP) has finished a report Biological Effects after Prenatal Irradiation (Embryo and Fetus) which has been approved by the Main Commission and Will be Published. Some new important scientific data shall be discussed in this contribution. During the preimplantation period lethality of the mammalian embryo is the dominating radiation effect. However, in mouse strains with genetic predispositions it has been shown that also malformations can be caused. This effect is genetically determined and its mechanisms is different from the induction of malformations during major organogenesis. Radiation exposures during this prenatal period leads ato an increase of genomic instability of cells in the normal appearing fetuses. These radiation effects can be transmitted to the next generation. A renewed analysis of individuals with severe mental retardation after exposures during the ...
The risks of genetic, leukemia and malignant diseases from medical X-ray diagnostic examinations were estimated using the frequency of radiographic and fluoroscopic exposures per diagnostic examination, child expectancy, leukemia and malignancy significant factors, and using a weighting factor determined on the basis of data concerning the cancer mortality among atomic bomb survivors in Nagasaki and of a recommendation of International Commission of Radiological Protection. The organ or tissue doses with respect to the stochastic risks were determined with ionization chambers and thermoluminescent dosimeters placed at the positions of the organs or tissues in a RANDO woman phantom which was exposed to diagnostic X-rays according to technical factors of typical radiographic and fluoroscopic examinations obtained from a nationwide survey. The resultant risks by age-group and type of radiographic and fluoroscopic examination are tabulated in terms ...
As a series of estimations of population doses and of risk estimates from medical exposures in Japan, the malignancy significant dose (MSD) and the fatal malignant risk from beam therapy were estimated based on a nationwide survey of radiotherapeutic treatments, using a malignancy significant factor and a weighting factor determined from the data on the cancer mortality among the atomic bomb survivors in Nagasaki. The effective dose was defined as a sum of the product of the weighting factor and the organ or tissue doses with respect to the malignant diseases. The organ or tissue doses were determined with ionization chambers placed at the positions of their center in a MixDp-phantom simulated lung tissues by a block of cork, using a telecobalt unit, a conventional X-ray unit and a medical linear accelerator. The organ or tissue doses were categorized into three dose components; namely 1) dose from useful beams; 2) scattered radiation dose from ...
An in/depth industrial hygiene survey of exposures to phosphine during the use of aluminum phosphide was conducted as part of a survey on exposure to grain fumigants. Area monitoring and breathing-zone sampling for phosphine were conducted during the addition of aluminum phosphide to grain during turning operations; source samples and peak personal exposures were also analyzed. Major sources of personal exposure included the escape of air from the bin headspace during filling with treated grain, filling and emptying of the phosphide pellet dispenser, and infiltration from the treated grain bin and from the pellet dispenser itself into adjacent air space. Relatively good dust control was indicated by the total dust samples collected during the survey. Measures recommended by the author are in the report.
Worker exposures to N-nitroso compounds were evaluated at B.F. Goodrich Company, Woodburn, Indiana on December 12, 1979. Personal and area air samples were collected and analyzed by gas-chromatography and thermal-energy-analysis methods. All of the samples contained N-nitrosomorpholine (NMOR) and five samples also contained N-nitrosodimethylamine (NDMA). The amount of NMOR ranged from 0.85 to 3.7 micrograms per cubic meter (micrograms/cu m) for area air samples and 0.63 to 1.8 micrograms/cu m for personal samples. NDMA concentrations ranged from undetectable to 1.8 microgram/cu m for area samples and undetectable to 0.09 micrograms/cu m for personal samples. The authors note that no exposure standards exist for NDMA or NMOR but both are listed as potential human carcinogens. They suggest that the ...
To obtain Pinus wood-plastic composites, wood samples were impregnated with methyl methacrylate and polymerized by the use of gamma rays from a /sup 60/Co at different dose exposure and total dose. The best percentage of polymerization was obtained with the exposure of 2.0 MR of gamma radiation. It was found that the impregnation and polymerization, determined by the density values along the samples were uniform. The density became 2.6 times higher in relation to the control samples. The storage of the impregnated wood samples showed losses of the monomer, even when wrapped with aluminum or polyethylene film. It is recommended that the wood samples should be irradiated soon after impregnation.
Eight recreational parks located in a Lyme disease endemic area of southern New York State were surveyed for the presence of ticks during the summer of 1985 by drag sampling. Ixodes dammini, the primary...Full Text Available
to Protect Workers' Rights); 2/28/07 [PDF - 1,030 KB] Submission to the docket from Eninger (private person); 3/1/07 [PDF - 174 KB] Submission to the docket from Farber (private...
One of the most important goals of the Italian survey, initiated in 1989, was to promote ad hoc policies to reduce radon exposure of the population. In the survey a statistical representative sample of 5000 dwellings was chosen; two six-month measurements were made of the indoor radon concentration, in combination with one six-month measurement of gamma exposure. The results of the radon concentration measurements are reported here: they refer to 80% of the sample. The annual mean value was 81.5Bq.m{sup -3}, which is higher than that reported for other industrialised countries. (author).
Short-duration measurements have been widely used to screen for exposures to elevated radon concentrations in individual houses or at state or regional levels. However, a number of factors, including spatial and temporal variability in radon concentrations, must be considered before comparison to concentration guidelines can be made. Daily variations in radon concentration can lead to inherent measurement uncertainties ranging from 20 to 100+ percent. Differences in radon concentration due to seasonal effects and/or sampling location are also variable, and do not appear to be regionally consistent. Winter/summer concentration ratios, for example, have been observed to vary by as much as a factor of 10 in basements and by a factor of 5 in first floors. In this paper the implications of these uncertainties on the use of short-term sampling for inferring long-term exposures are discussed.
This paper studies the effect upon the thermoluminescence (TL) signal of four feldspar samples of exposing them to infrared stimulation, as occurs during infrared-stimulated luminescence (IRSL) measurement. Together with pulse annealing measurements these results are used to show which part of the TL signal is removed by exposure to IR and which part is directly related to the IRSL signal that is observed. When the samples are preheated prior to measurement in order to remove any low-temperature (< 200"oC) TL signals, a linear relationship is observed between the amount of TL that is lost and the IRSL light sum that is produced. The IRSL light sum is consistently four times larger than the amount of TL that is lost. Three possible explanations are proposed for this, but no conclusive evidence could be obtained to support any of them. A close similarity is observed in the pulse annealing results and the loss of TL due to ...
The activity concentrations of potassium, uranium and thorium in minerals and soil samples from a mining site in Ibadan, Southwestern Nigeria were measured using gamma ray spectroscopy method. Effective dose per annum has been calculated from the activity concentrations of dominant gamma-emitting natural radionuclides, potassium, uranium and thorium. Samples collected include minerals (beryl, quartz and feldspar), soil samples from the mining pits, heaps and undisturbed land around the mining site. The activity concentrations of "4"0K, "2"3"8U and "2"3"2Th, respectively in Bq kg-1 in the mineral samples were as follows: 1985 #+-# 16, 4.8 #+-# 0.9 and 11.8 #+-# 5.8 for beryl sample, 115.1 #+-# 27.9, 5.0 #+-# 1.3 and 6.3 #+-# 5.0 for feldspar samples and 1421 #+-# 122, <4.8 and 20.1 #+-# 3.5 for quartz samples. For the soil ...
Environmental exposure measurements are, in general, positive and may be subject to left censoring; i.e,. the measured value is less than a ''detection limit''. In occupational monitoring, strategies for assessing workplace exposures typically focus on the mean exposure level or the probability that any measurement exceeds a limit. Parametric methods used to determine acceptable levels of exposure, are often based on a two parameter lognormal distribution. The mean exposure level, an upper percentile, and the exceedance fraction are used to characterize exposure levels, and confidence limits are used to describe the uncertainty in these estimates. Statistical methods for random samples (without non-detects) from the lognormal distribution are well known for each of these situations. In this report, methods ...
A number of noise equivalent quanta (NEQ(u)) has been used in the evaluation of imaging systems. In this paper, we have evaluated the image quality of Fuji computed radiography (FCR) using of NEQ (u) and considered with the effects of the aliasing error of the FCR. The noise samples of the FCR were made by three different exposure levels, and one of these has the same exposure level of the screen-film system. These samples were set with the same characteristic curve condition as that of the screen-film system. Results indicate that NEQ (u) of the FCR system at low frequencies varies depending on the exposure level. On the same exposure level, NEQ(u) of screen-film system has a higher value than that of FCR in the frequency region over 2.5 cycles/mm. Moreover, the aliasing error of FCR increases at the frequency region over 5 cycles/mm. We concluded that it is ...
A number of noise equivalent quanta (NEQ(u)) has been used in the evaluation of imaging systems. In this paper, we have evaluated the image quality of Fuji computed radiography (FCR) using of NEQ (u) and considered with the effects of the aliasing error of the FCR. The noise samples of the FCR were made by three different exposure levels, and one of these has the same exposure level of the screen-film system. These samples were set with the same characteristic curve condition as that of the screen-film system. Results indicate that NEQ (u) of the FCR system at low frequencies varies depending on the exposure level. On the same exposure level, NEQ(u) of screen-film system has a higher value than that of FCR in the frequency region over 2.5 cycles/mm. Moreover, the aliasing error of FCR increases at the frequency region over 5 cycles/mm. We concluded that it is ...
A survey to assess the techniques used to control occupational exposure to formaldehyde (50000) and methanol (67561) was conducted at the E. I. DuPont de Nemours and Company (SIC-2869) formaldehyde production unit, Linden, New Jersey, in October 1982. Exposure concentrations were reduced primarily by the use of a process that was completely enclosed except for process sampling, methanol unloading, and formaldehyde discharge points. Local and area exhaust ventilation, and work practices were also used to control exposures. Formaldehyde concentrations in the absorber area were controlled by burning the exit gases in an afterburner and discharging them high above the ground. Analysis of area and breathing zone samples showed methanol and formaldehyde concentrations below the OSHA limits of 200 and 3 parts per million, respectively. The authors conclude that workers are not overexposed ...
The real-time dose assessment system under development has been updated and the technology for tracer experiment has been established. The calculation of external gamma dose is the most difficult and time-consuming part of the dose calculations. The characteristics of external gamma exposure have been investigated and the method for reducing the calculation time has been devised. The internal exposure via the ingestion of the contaminated foodstuffs is one of the important pathways to the total radiological exposure. In the emergency, it is necessary to take an action such like food ban to protect the internal exposure. An algorithm for the interface between the real-time system and the food chain model has been provided. The second field tracer experiment over flat terrain has been carried out on a plain in Iksan city in Junrabook-Do. Sequential tracer sampler which can be sampled ...
For the purpose of risk estimates from radiation carcinogenesis including leukemogenesis and radiation genetic effects, the biological significant dose is not the tissue kerma in air but the absorbed dose in organ or tissue with respect to carcinogenic and leukemogenic effects or genetic effects. In order to estimate organ or tissue dose from the tissue kerma in air, a ratio of the organ or tissue dose to the tissue kerma in air for survivors in Hiroshima and Nagasaki was calculated with the aid of the Snyder's mathematical phantoms constructed so as to simulate the body shape of survivors aged 5, 10 years old and adult at the time of atomic bomb detonations. The ratios were corrected for the angular distribution of atomic bomb radiations, assuming an anisotropic angular distribution for the survivors exposed to the atomic bombs in open air and the isotropic distribution for the survivors incide a Japanese house or other structures. The resultant ratios are ...
Worker exposures to arsenic (7440382) (As), cadmium (7440439) (Cd), copper (7440508) (Cu), lead (7439921) (Pb) and sulfur-dioxide (7446095) (SO2) were surveyed at ASARCO, Incorporated (SIC-3331) in Hayden, Arizona on April 23 and 24, 1980. The evaluation was requested by an authorized representative of the United Steel Workers, Local 886, on behalf of an unspecified number of workers. Personal and area air samples were collected in the pug mill department, and workers were tested for blood Pb and urinary As concentrations. All four personal samples for As exceeded the OSHA standard of 10 micrograms per cubic meter, one sample exceeded the Cu dust standard of 1 milligram per cubic meter (mg/cu m), and one sample exceeded the Pb standard of 50 micrograms per cubic meter. Exposures to Cd fume, Cd dust, and SO2 were below the respective OSHA standard of 0.2mg/cu m, ...
A survey is presented of the consequences of the irradiation of the population with ionizing radiation. There is an increased incidence of leukemia in irradiated population groups. Among the inhabitants of Hiroshima and Nagasaki maximum death of leukemia was observed in the years 1951 to 1952. The results are summed up of the observation of carcinoma of the breast, lungs and bronchi, bones, and carcinoma of the thyroid. The effect of radiation on experimental animals is described. It was found that the scatter of the dependence of the incidence of various types of cancer on the dose equivalent apparently reflects differences in the biological mechanism of this incidence and that a proportional relationship cannot be expected between the primary damage of cells during irradiation and the actual manifestation of the disease. (E.S.).
The activity concentrations of potassium, uranium and thorium in minerals and soil samples from a mining site in Ibadan, Southwestern Nigeria were measured using gamma ray spectroscopy method. Effective dose per annum has been calculated from the activity concentrations of dominant gamma-emitting natural radionuclides, potassium, uranium and thorium. Samples collected include minerals (beryl, quartz and feldspar), soil samples from the mining pits, heaps and undisturbed land around the mining site. The activity concentrations of {sup 40}K, {sup 238}U and {sup 232}Th, respectively in Bq kg-1 in the mineral samples were as follows: 1985 +- 16, 4.8 +- 0.9 and 11.8 +- 5.8 for beryl sample, 115.1 +- 27.9, 5.0 +- 1.3 and 6.3 +- 5.0 for feldspar samples and 1421 +- 122, <4.8 and 20.1 +- 3.5 for quartz samples. For the soil ...
An in-depth industrial hygiene survey was conducted to evaluate worker exposures to phosphine during fumigation of grain at the Early and Daniel Co. grain elevator in Louisville, Kentucky. Stored grain was fumigated using aluminum phosphide. Aluminum-phosphide pellets were also added directly to the grain by the blender as it was poured into the storage containers. Local exhaust ventilation was used at points in the grain-moving system where grain dust was generated. Air samples were taken during full-shift periods at the breathing zone of the weighmaster, two bin floormen, and the blender. Area monitoring samples were also taken. If the operators spend considerable time in the vicinity of a bin which is being filled with grain, there is a likelihood of far greater exposure levels being noted. According to the author, further studies of the use of phosphide products at other elevators should be ...
Radon exposure assessment in case-control studies on radon and lung cancer is generally based on contemporary radon concentration measurements, which can be affected by significant changes in the building structures or in living habits. Another method to estimate the radon exposure of the subjects is the recently developed retrospective dosimetry technique based on the {sup 210}Po surface activity from glass objects. In order to compare the results obtained by the two methods, a study has been carried out in a sample of 26 dwellings in Rome, with radon concentration values ranging from 28 to 623 Bq m{sup -3}. Retrospective detectors based on CR-39 and LR 115 were exposed on 50 glass objects in bedrooms and living rooms. The correlation factor between the two sets of data, after removing six extreme values, is 0.67, which is similar to results obtained in other validation studies of similar sample size. ...
A community health survey of 438 individuals was taken to detect health problems related to high voltage electrical transmission among an adjacent residential population. Results revealed no significant or consistent relationships between exposure to a high voltage DC power line and the perceived health problems that were measured. The sample was not, however, large enough to draw statistically significant conclusions regarding possible health effects with a very low incidence.
Samples of geothermal scale formed from Magmamax No. 1 and Woolsey No. 1 wells in the Imperial Valley, Calif., were exposed to concentrated and dilute solutions of common laboratory reagents. The time of exposure and temperature of the reagent were also varied. Several reagents easily dissolved significant amounts of the scale. An in situ test was performed with marginal success.
Chronic workplace exposure to formaldehyde and solvents at low doses reduced pulmonary function in 280 non-smoker white women working as histology technicians. They were studied during national workshops...Full Text Available
The author discusses the accelerated aging tests performed using Hondo and Maya as aging resids with a commercial large pore hydrotreating catalyst. The results from these tests were compared with those obtained under a normal full life test. The test resid was a sample of a typical refinery charge and the activities for sulfur and vanadium removal were determined at 720"0F after successive brief periods of exposure to the heavier oils.
Radiation damage and its recovery in the light emittance efficiency and the attenuation length of barium fluoride (BaF_2) scintillator have been investigated. The light yield and transmittance of small samples of BaF_2 scintillator were measured after #gamma#-irradiation from 0.5x10"4 to 1.1x10"5 Gy for deterioration, and after sunlight exposure for recovery. Suspension of deterioration was observed both in light yield and in attenuation length at an integrated dose of #gamma#-rays of about 10"4 Gy. Fairly good and quick recovery of the deteriorated BaF_2 scintillator was obtained by sunlight exposure. Using a Monte Carlo simulation method, the dependence of the light emittance efficiency on #gamma#-irradiation and sunlight exposure was studied. It has been found that the light emittance efficiency, as well as the attenuation length, is influenced by #gamma#-irradiation and sunlight ...
The Rocky Flats Environmental Technology Site (RFETS) has historically released radionuclide chemicals of potential concern into the surrounding environment. The off-site environment was evaluated for Pu"2"3"9"/"2"4"0 and Am"2"4"1 occurrence. An evaluation of exposure and effects to the aquatic ecology within off-site areas including: Standley Lake, Great Western Reservoir, Mower Reservoir and portions of Big Dry Creek, Walnut Creek, and Woman Creek was performed for the completion of an Ecological Risk Assessment. Collocated sampling activities were performed for surface water, sediment, benthic macroinvertebrates and fish. Results of the analytical data were used to assess ongoing exposure and effects. Data collected to determine effects (chemical content of fish tissue, diversity and density of macroinvertebrate populations) provided some of the necessary information needed to evaluate risk. However, due to conditions of ...
Large-scale field tracer experiments have been conducted on Ulchin and Wolsung nuclear sites for the purpose of validating FADAS and of analyzing the environmental characteristics around the nuclear site. The most influential factor in atmospheric dispersion is the meteorological condition. During the experiment, meteorological data were measured on the release point and the selected positions among sampling points. Once radioactive materials are released to the atmosphere, members of public may be exposed through the environmental media such as air, soil and foods. Therefore, to protect the public, adequate countermeasures should be taken at due time for those exposure pathways. Both processes of justification and optimization are applied to a countermeasure simultaneously for decision-making. The work scope of biological research for the radiation protection had contained the search of biological microanalytic methods for the assessment of ...
In an attempt to obtain basic data for evaluation of exposure doses in Niigata Prefecture, the concentrations of tritium in atmospheric water, precipitation, river water, and tap water were measured. Samples of atmospheric water, river water, and tap water were collected once for 2 weeks; and precipitation collected for one week was used as sample. The concentration of atmospheric tritium depended on the concentration of tritium in moisture and the content of water in atmosphere. Tritium levels were high in May, November and March, and low in September. Regarding tritium concentrations, there was a good correlation between atmospheric water and precipitation. Tritium concentrations in both of them varied from sample to sample. The concentrations of tritium in river and tap water tended to be high during spring and low during summer and winter, although the variations were not so ...
The authors summarize the significant dose-related effects on brain development which have emerged largely within the last six years of study of prenatally exposed A-bomb survivors. The results are described primarily in terms of the DS86 estimates and differences between these and the older T65DR dose estimates are discussed. The severe mental retardation sample was based on 1598 individuals taken from the PE-86 sample, and the intelligence test scores considered from the same sample involved 1673 children. The authors also discuss some of the recent neurobiological developments that appear relevant to an understanding of the biological bases of dose-related events observed, and suggest future research that may contribute either to further delineation of exposure consequences or to the explanation of the cellular and molecular origins of observed effects. (UK).
Although infrared-stimulated luminescence (IRSL) signals in feldspars can be bleached rapidly by sunlight, there could still be a small amount of IRSL signal remaining in sediment grains if they have experienced only relatively short sunlight exposure before deposition. This remaining signal results in a ''remnant dose'' stored in the grain and is important for young samples but negligible for old samples. Several methods have been introduced to detect insufficient bleaching, and some of them can provide information on the extent of the bleaching. Others can only distinguish between samples bleached for a very long time and for a short time. Empirical methods are introduced to evaluate the possible values of equivalent dose accumulated since the grains were deposited. These methods involve the analysis of the equivalent doses and the natural IRSL signals obtained using single-disc dose determination ...
The Ringold Formation consists of lacustrine and fluvial deposits overlying the Columbia River Basalt. The Ringold Formation, because of its thickness, extent, and age, is an excellent unit in which to detect and possibly data the deformation that has occurred since deposition of the basalt. One objective of this study was to investigate the paleomagnetism of the upper Ringold unit exposed at one location in the White Bluffs in enough detail to resolve, with reasonable confidence, the magnetostratigraphy of the rock units sampled. The other objective was to evaluate, in a preliminary manner, the paleomagnetic favorability and magnetostratigraphy of the subsurface Ringold Formation in the Pasco Basin and at selected exposures outside the Pasco Basin. The scope of this study was the collection of 300 paleomagnetic samples, their measurement, and analysis. Samples were collected from the White Bluffs, from ...
Low molecular weight epoxy resin based on diglycidyl ether of bisphenol A was synthesized and mixed at constant percentages with natural rubber. The rubber epoxy system was cured with various types of curing agents such as ethylene diamine, maleic anhydride as well as the prepared resole phenol formaldehyde. A study of the photo-induced crosslinking of the prepared elastic adhesives and film samples was carried out by exposure to ultraviolet lamp (300 w) for 2 weeks at 20 deg. C. Samples containing ethylene diamine were cured at 25 + - 1 deg. C. for 24 h while samples containing maleic anhydride or resole phenol formaldehyde resins were thermally cured at 150-170 deg. C. for 10 min. Cured adhesive compositions were tested mechanically and physically and evaluated as wood adhesives. While hardness, chemical resistance as well as heat stability of the prepared cured film sample were ...
A sample of 30 manganese-exposed foundry workers from two Swedish plants were examined with a partly computerized psychological test battery, comprised of 10 performance tests. Performance of the manganese-exposed workers was compared to that of a matched control group of 60 workers. Matching criteria were age, geographical area, type of work, and the results on a test of verbal comprehension. Performance of the exposed workers was inferior to that of the control group on tests of simple reaction time, digit span, and finger tapping. No correlations were found between performance and the present manganese exposure levels or the number of years employed in manganese work. The results seem to indicate that the present exposure standards for manganese, in Sweden 2.5 mg/m3 and in most other countries 5 mg/m3, are not sufficient to protect workers from negative effects on performance capacity.
Ribbon parachute fabrics were tested during development and production of a 24 ft parachute, and after 2.5 years ambient exposure at several storage sites. The effects of sewing, packing, and parachute deployment on material strength were obtained in the 1000 lb Kevlar ribbon after moisture exposure during packing, and when packed parachutes absorbed moisture or were thermal cycled. Individual yarn samples from the low strength ribbons exhibited little change in strength indicating that the material itself had not degraded. Factors leading to the change in ribbon strength are discussed. Considering all materials, there have been no indications to date of any uncontrollable changes in material strength that would limit the use of Kevlar in parachute applications.
A female employee was exposed to lead dust for 8 h daily from 4.5.1982 to 20.5.1982. During this time conception occurred (1st day of last menses 4.5.82). Acute symptoms of lead intoxication were not observed in this subject but were in other employees. Measurements of lead content were started after the end of exposure and continued for 6 months until normal values were obtained. Because of the half-life of nearly 20 days for lead elimination from blood the estimated body burden at the end of exposure was about 1200 ppb. The fetal tissue samples contained between 0.4 (brain) and 7.9 (liver) ..mu..g lead/g dry weight. The fetal lead was mainly stored in bone, blood and liver. From the results given a delayed elimination of fetal lead is suggested.
An important aspect of ecosystem sustainability is the ability to withstand and recover from disturbance or stress. In this study, we investigated the effect of a heat-disturbance on soil microbial biomass, microbial activity in response to the addition of organic acid (malate), and microbial community structure in a laboratory experiment. The soils investigated were from a jarrah (Eucalyptus marginata) forest that had undergone rehabilitation following bauxite mining 12 years previously. Soils from a full factorial of two field treatments; contour ripping induced micro-topography (mound or furrow) and prior exposure to prescription fire (burnt or non-burnt), were sampled and found to exhibit treatment-dependent differences in soil biological and chemical properties. Exposure of soil micro...
Large-scale field tracer experiments have been conducted on Ulchin, Wolsung and Daeduk sites for the purpose of validating FADAS and of analyzing the environmental characteristics around the nuclear sites. The most influential factor in atmospheric dispersion is the meteorological condition. During the experiment, meteorological data were measured on the release point and the selected positions among sampling points. Once radioactive materials are released to the atmosphere, members of public may be exposed through the environmental media such as air, soil and foods. Therefore, to protect the public, adequate countermeasures should be taken at due time for those exposure pathways. both processes, of justification and optimization are applied to a countermeasure simultaneously for decision-making. The work scope of Biological research for the radiation protection had contained the search of biological microanalytic methods for assessing the ...
The procedure for field corrosion tests in sea water is decribed in DIN 50 917, Part II. Distinction is made thereby between long-term undisturbed test specimens, which remain at the exposure site up to the time of sampling, and disturbed test specimens, which are cleaned at certain time intervals for intermediate examination and subsequently exposed again. The comparability of results obtained with the two different types of test was to be investigated at the Helgoland test installation. At an exposure period of up to four years, undisturbed specimens of unalloyed and low-alloy steel grades feature considerably lower corrosion losses than disturbed specimens. At a longer exposure period of up to seven years, the corrosion rate can increase substantially again with the exposure time. This can be attributed to sulphate reduction in the anaerobic zone under the top coating. An effect ...
An aerial radiological survey was performed from 11 to 20 March 1982 over a 260-square-kilometer area centered on the Grand Gulf Nuclear Station at Port Gibson, Mississippi (the station was not yet in operation at the time of the survey). All gamma ray data were collected by flying east-west lines spaced 152 meters apart at an altitude 91 meters above ground level. Processed data showed that all gamma rays detected within the survey area were those expected from naturally occurring terrestrial background emitters. Count rates obtained from the aerial platform were converted to exposure rates at 1 meter above the ground and are presented in the form of an isoradiation contour map. The observed exposure rates were between 5 and 13 microroentgens per hour (#mu#R/h), with most of the area ranging from 9 to 10 #mu#R/h. These values include an estimated cosmic ray contribution of 3.6 #mu#R/h. The exposure rate obtained from soil ...
Dust detection and control in real time, represent one of the most challenging problem in all those environments where fine and ultrafine airborne particulate solids products are present. The presence of such products can be linked to several factors, often directly related and influenced by the working-production actions performed. Independently from the causes generating dust, airborne contaminants are an occupational problem of increasing interest as they are related to a wide number of diseases. In particular, airborne dusts are well known to be associated with several classical occupational lung diseases, such as the pneumoconiosis, especially at high levels of exposure. Nowadays there is also an increasing interest in other dust related diseases, from the most serious as cancer and asthma, to those related with allergies or irritation and other illnesses, also occurring at lower levels of exposure. Among the different critical factors ...
Lyophilized human whole blood control material containing lead was prepared for internal and external quality assurance to evaluate and improve the analytical performance of lead. The samples were prepared in four different concentrations from outdated human whole blood stabilized with glucose and a citrate/phosphate buffer and provided under clean room conditions to avoid contamination. The lyophilized samples are easy to reconstitute with water. The materials were evaluated according to a statistical model. The lead concentrations in the specimens are close to blood lead levels usually following environmental and industrial exposure, particular in occupational health to the control of lead exposure at work regulations. The materials are available to the commercial as well as the scientific community. The Danish External Quality Assessment Scheme (DEQAS) for lead in blood is intended to complement the ...
The effectiveness of Noveko's antimicrobial filter was evaluated after 16 months of exposure to commercial swine production. The experiment involved the use of a scaled model of a commercial swine facility consisting of 2 small chambers connected by a duct containing the filters. A 5 kg naive pig was placed in the reception chamber for a period of 6 hours after aerosolization with porcine reproductive and respiratory syndrome virus (PRRSV). Blood samples from pigs were collected before and after aerosolization to test for the presence of PRRSV RNA. Only blood samples were tested for PRRSV antibodies by IDEXX 2XR ELISA. None of the 9 pigs tested were found to be infected. The study showed that the technology used to integrate the antimicrobial agent into the filter fibers allows the filter combination to withstand extreme weather and endure commercial swine production for at least 16 months, and can maintain its ...
Fission track analysis (FTA) technique for the determination of "2"3"9Pu excreted through urine has been standardized using blank samples, tracer and "2"3"9Pu spikes. Double stage anion exchange separation protocol has been applied and an average radiochemical recovery of "2"3"9Pu of 18% was obtained. An average track registration efficiency of 11 tracks per #mu#Bq of "2"3"9Pu, irradiated to 0.35x10"1"7 neutron fluence was established. Reagent blank urine samples from 11 controlled subjects were analyzed by FTA and an average of 149#+-#14 tracks was obtained. Minimum detectable activity of 34 #mu#Bq L"-"1 of urine sample was obtained and will be useful for monitoring chronic exposure cases handling MOX fuel.
The authors have made new and improved measurements of the neutron capture and total cross sections of {sup 88}Sr at the Oak Ridge Electron Linear Accelerator (ORELA). Improvements over previous measurements include a wider incident neutron energy range, the use of metallic rather than carbonate samples, better background subtraction, reduced sensitivity to sample-dependent backgrounds, and better pulse-height weighting functions. Because of its small cross section, the {sup 88}Sr(n,{gamma}) reaction is an important bottleneck during the s-process nucleosynthesis. Hence, an accurate determination of this rate is needed to better constrain the neutron exposure in s-process models and to more fully exploit the recently discovered isotopic anomalies in certain meteorites. They describe the experimental procedures, compare the results to previous data, and discuss their astrophysical impact.
Exposure tests of candidate materials were carried out up to 1000 hr in the sulfuric acid environments of thermochemical hydrogen production IS process, focusing on the corrosion of welded portion and of crevice area. In the gas phase sulfuric acid decomposition condition at 850degC, welded samples of Alloy 800 and of Alloy 600 showed the same good corrosion resistance as the base materials. In the boiling condition of 95 wt% sulfuric acid solution, test sample of SiC showed the same good corrosion resistance. Also negligible corrosion was observed in crevice corrosion. (author)
Varroa destructor is an ectoparasitic mite that affects colonies of honey bee Apis mellifera worldwide. In the last years, substances of botanical origin have emerged as natural alternative acaricides to diminish the population levels of the mite. In the present work, the bioactivity of propolis from different geographical locations of Pampean region from Argentina on V. destructor was evaluated. Fourteen propolis samples were organoleptic and physicochemically characterized and, by means topical applications, their activity was tested on mites. All propolis had a homogeneous composition and the bioactivity levels against mites were comparable among the different propolis samples. The percentage of mites killed by the treatments ranged between 60.5% and 90% after 30?s of exposure. Thus, V....
The iodinated oil lipiodol is commonly used as a carrier for in situ delivery of drugs or radioactivity to hepatic tumors. Recently, we reported a new kit formulation for high-activity labeling of lipiodol with the {beta}-emitting radionuclide Re-188. Since the whole preparation involves different steps and complex manipulations of high-activity samples, we describe here an automated synthesis module that allows the easy preparation of sterile and pyrogen-free samples of Re-188 lipiodol ready to be administered to the patient. Important advantages include the possibility to incorporate high Re-188 activity into the lipiodol hydrophobic phase and a sharp reduction of radiation exposure of the operator assisting the labelling procedure. Application of this modular reaction system could be also extended to the preparation of other Re-188 radiopharmaceuticals and to compound labelled with different {beta}-emitting therapeutic ...
Thermal analysis testing revealed slight weight changes, which were a function of gamma irradiation, in a highly reduced Defense Waste Processing Facility (DWPF) simulated waste glass. Transmission electron microscopy (TEM) was performed on this glass to determine if the weight change corresponded to microstructural variations. TEM analyses showed that no microstructural changes were attributable to gamma irradiation. Exposure of the samples to the electron beam in the TEM did cause changes in the glass microstructures in some cases. These changes were likely due to localized heating of the glass due to interactions with the transmitted electrons.
Many analytical chemistry methods normally used at the Savannah River site require repetitive procedures and handling of radioactive and other hazardous solutions. Robotics is being investigated as a method of reducing personnel fatigue and radiation exposure and also increasing product quality. Several applications of various commercially available robot systems are discussed involving cold (nonradioactive) and hot (radioactive) sample preparations and glovebox waste removal. Problems encountered in robot programming, parts fixturing, design of special robot hands and other support equipment, glovebox operation, and operator-system interaction are discussed. A typical robot system cost analysis for one application is given.
Retention kinetics and tissue partition coefficients for "8"5Kr were determined in rats exposed to known concentrations of "8"5Kr gas. The tissue partition coefficients were used to calculate the relative tissue radiation dose, assuming exposure conditions equivalent to the maximum permissible concentration in air (MPC)a. The estimated radiation dose was highest in adrenals and body fat, about twice the dose estimated for the next highest tissue, ovaries. Saturation and desaturation curves show that the contents of the large intestines have a prolonged desaturation time compared to other samples analyzed.
In response to a request from the International Chemical Workers Union, Akron, Ohio, an investigation was made into possible hazardous working conditions at two American Smelting and Refining Company (SIC-1031) zinc mines (New Market and Young) in Mascot, Tennessee. Specifically, exposures to asbestos (1332214), silica (14808607), and diesel emissions were determined. At both mines overexposures were found to nitrogen-dioxide (10102440) (NO2) and coal-tar pitch volatiles. Twenty-four percent of the NO2 measurements taken were above the NIOSH recommended ceiling of 1 part per million (ppm), but none exceeded the Mine Safety and Health Administration's (MSHA) ceiling of 5ppm. Exposure to diesel particulates ranged from 0.24 to 1.06mg/cu m. None of the 52 respirable dust samples collected exceeded the calculated MSHA limits for free silica exposure. A medical evaluation was offered and 83 of the ...
The objective of the Hanford Environmental Dose Reconstruction Project (HEDR) is to estimate the potential radiation doses received by people living within the sphere of influence of the Hanford Site. A potential critical pathway for human radiation exposure is through the consumption of waterfowl that frequent onsite waste-water ponds or through eating of fish, shellfish, and waterfowl that reside in/on the Columbia River and its tributaries downstream of the reactors. This document summarizes information on fish, shellfish, and waterfowl radiation contamination for samples collected by Hanford monitoring personnel and offsite agencies for the period 1945 to 1972. Specific information includes the types of organisms sampled, the kinds of tissues and organs analyzed, the sampling locations, and the radionuclides reported. Some tissue concentrations are also included. We anticipate that these yearly ...
The objective of the Hanford Environmental Dose Reconstruction Project (HEDR) is to estimate the potential radiation doses received by people living within the sphere of influence of the Hanford Site. A potential critical pathway for human radiation exposure is through the consumption of waterfowl that frequent onsite waste-water ponds or through eating of fish, shellfish, and waterfowl that reside in/on the Columbia River and its tributaries downstream of the reactors. This document summarizes information on fish, shellfish, and waterfowl radiation contamination for samples collected by Hanford monitoring personnel and offsite agencies for the period 1945 to 1972. Specific information includes the types of organisms sampled, the kinds of tissues and organs analyzed, the sampling locations, and the radionuclides reported. Some tissue concentrations are also included. We anticipate that these yearly ...
The objective of the Hanford Environmental Dose Reconstruction Project (HEDR) is to estimate the potential radiation doses received by people living within the sphere of influence of the Hanford Site. A potential critical pathway for human radiation exposure is through the consumption of waterfowl that frequent onsite waste-water ponds or through eating of fish, shellfish, and waterfowl that reside in/on the Columbia River and its tributaries downstream of the reactors. This document summarizes information on fish, shellfish, and waterfowl radiation contamination for samples collected by Hanford monitoring personnel and offsite agencies for the period 1945 to 1972. Specific information includes the types of organisms sampled, the kinds of tissues and organs analyzed, the sampling locations, and the radionuclides reported. Some tissue concentrations are also included. We anticipate that these yearly ...
We present changes in the p53 gene in a group of 70 thyroid tumours and 40 blood samples obtained from children from Belarus. Three thyroid tumours show a polymorphism in exon 6 (codon 213) and 5 tumours show a polymorphism in intron 6, 37 bp upstream to the 5'-end of exon 7. Only one patient has a mutation in exon 7 (codon 258) resulting in an amino acid substitution in the protein p53. The distribution of polymorphisms in the 40 blood samples was as follows: three patients had a polymorphism in exon 6 and two persons had a polymorphism in intron 6. One polymorphism in intron 6 was also found in the group of 30 healthy children from Belarus. The fact that the differences in the sequence in p53 found in the tumours was also seen in the blood of these patients demonstrates that they are polymorphisms not induced by radiation exposure. It is difficult to conclude, if the polymorphisms found by us could be associated with the ...
Stearic acid (C{sub 1}8H{sub 36}O{sub 2}) was treated into Ar and Ar-O{sub 2}(10%) pulsed DC discharge created by a cathode-anode confined system. The samples were placed at the floating potential. The results show that the mass variation of the stearic acid samples after Ar-O{sub 2} plasma exposure is more important than the pure Ar plasma treatments. This comportment demonstrate that the oxygen actives species (O and O{sub 2} in all states) strongly enhance the etching process with regards to A{sup *} species, regardless of their concentration. After treatment by Ar and Ar-O{sub 2} plasma, analyses by X-ray diffraction show a significant structural modification of the samples surface, utilizing Ar-O{sub 2} plasma the modification was more pronounced. The chemical composition evolution shows that the acid function is etched preferentially in the beginning of the treatment (about 5 min) and that after ...
For the estimation of the dispersion trend of tritium discharged from the Wolsung nuclear power plant, the present level of tritium in environmental samples in the vicinity of the Wolsong site has been studied. On the basis of tritium concentrations in environmental samples, the effective dose due to tritium has been estimated for an individual and population within a 16 km radius from the Wolsong site. The annual effective dose of tritium to an inhabitant around the Wolsong site ranged from 0.15 microSv y-1 to 1.3 microSv y-1. The dose level was negligible and much lower than some applicable standards, i.e. the limit on exposure from nuclear fuel cycle to the general public as recommended by ICRP (1 mSv y-1) or US EPA's limit (0.25 mSv y-1). The collective dose to the total population within a 16 km radius from the site, 1.2 x 10(-2) man.Sv y-1 was much lower than 1 man.Sv y-1, an applicable criterion for the so-called ...
We present the X-ray properties of a sample of 17 radio sources observed with the Chandra X-ray Observatory as part of a project aimed at studying the X-ray emission from their radio jets. In this paper, we concentrate on the X-ray properties of the unresolved cores. The sample includes 16 quasars (11 core-dominated and 5 lobe-dominated) in the redshift range z=0.30--1.96, and one low-power radio-galaxy at z=0.064. No diffuse X-ray emission is present around the cores of the quasars, except for the nearby low-power galaxy that has diffuse emission on a scale and with a luminosity consistent with other FRIs. No high-amplitude, short-term variability is detected within the relatively short Chandra exposures. However, 1510-089 shows low-amplitude flux changes with a timescale of $\\sim$25 minutes. The X-ray spectra of the quasar cores are generally well described by a single power law model with Galactic absorption. However, ...
Extra-fine powdered activated charcoal has been used as stationary phase (coating layer) in solid-phase microextraction (SPME). The efficiency and reliability of the prepared device have been investigated for the extraction of some volatile organic compounds such as benzene, toluene, ethylbenzene and xylene isomers (BTEX) from the headspace of water samples. Monitoring of the extracted compounds and further quantitative analysis of the real samples have been performed by capillary GC-FID. Effects of several factors such as temperature, addition of salt, and stirring speed on extraction efficiency and exposure time have been studied. Under optimum conditions, extraction recoveries for these compounds from 50 mL water were >95%. The calibration graphs were linear in the range 5 to 10{sup 4} pg mL{sup -1} and the detection limit for each BTEX compound was 1.5-2 pg mL{sup -1}. The results obtained by use of this porous layer ...
Electromagnetic fields have been reported to cause a variety of biological effects. It has been hypothesized that many of these phenomena are mediated by a primary effect on the concentration of cytosolic free calcium ((Ca2+)i). We investigated the effects of exposure to electromagnetic fields on (Ca2+)i in HL-60 cells using the Ca2(+)-sensitive fluorescent indicator indo-1. Indo-1-loaded cell samples were exposed to a radiofrequency electromagnetic field, a static magnetic field, and a time-varying magnetic field, which were generated by a magnetic resonance imaging (MRI) unit. We found that a 23-min exposure to all three fields, in combination, induced a significant increase in (Ca2+)i of 31 +/- 8 (SE) nM (P less than 0.01, n = 13) from a basal level of 121 +/- 8 nM. Also, cells exposed to only the time-varying magnetic field had a mean (Ca2+)i that was 34 +/- 10 nM (P less than 0.01, n = 11) higher than parallel control ...
The emission isolation flux chamber (EIFC) methodology was applied to Superfund investigations at the Lawrence Livermore National Laboratory Site 300 to determine if on-site workers were exposed to VOCs volatilizing from the subsurface and what, if any, health risks could be attributed to the inhalation of the VOCs volatilizing from the subsurface. During July and August of 1996, twenty, eighteen, and twenty six VOC soil vapor flux samples were collected in the Building 830, 832, and 854 areas, respectively using EIFCS. The VOC concentrations in the vapor samples were used to calculate soil flux rates which were used as input into an air dispersion model to calculate ambient air exposure-point concentrations. The exposure-point concentrations were compared to EPA Region IX Preliminary Remediation Goals (PRGs). Buildings 830 and 832 exposure-point concentrations were less then the ...
Full text: The surface properties of poly (tetrafluoroethylene) (PTFE) are changed by the exposure to synchrotron radiation (SR). We succeeded in controlling the wettability of the PTFE surface from hydrophobic to hydrophilic by varying the substrate temperature during the SR irradiation and found that the wettability was ascribable to microstructure and chemical composition of surface.In these previous works, oxygen atoms were found to inhabit on the hydrophobic surface of PTFE. In this study, we investigated the surface modification of PTFE from the SR exposure experiment under the O_2 gas atmosphere. The SR exposure to the PTFE sheet was carried out at beamline 6 (BL6) of the New- SUBARU. The PTFE sheet was irradiated to the white beam, ranging 50-1000 eV at BL6 at room temperature. The gas cell was mounted at the irradiation chamber. The O_2 gas pressure in the gas cell can be maintained at about 0.20 Pa during the SR ...
Ramsar, a city in the northern Iran, has the highest level of natural background radiation in the world. It has been clearly shown that low doses of ionising radiation can induce resistance to subsequent higher exposures. This phenomenon is termed radioadaptive response. We have compared induction of cytogenetic radioadaptive response by High Natural Background Radiation (HNBR) in Ramsar and X-ray occupational exposure as conditioning doses in human peripheral blood lymphocytes. 30 healthy control individuals, living in Ramsar but in normal background radiation areas, 15 healthy individuals from Talesh Mahalleh, a region with extraordinary high level of background radiation, and 7 X-ray radiographers working in Ramsar hospital located in normal natural background ionising radiation area were evaluated. Peripheral blood samples were prepared and exposed to challenge dose of 0 and 2 Gy. Lymphocytes were scored using analysis ...
This human investigation of lead absorption from the lungs utilized two forms of lead, lead chloride and lead hydroxide; the former was used in picogram amounts and the latter at microgram levels. These two species of lead were selected in an attempt to simulate the range of physicochemical properties found in atmospheric lead (urban air). Aerosols labeled with lead-203 were made of comparable aerodynamic size by using sodium chloride as the deposition-determining aerosol. After brief, mouthpiece exposures, 17 subjects were followed by serial counting with a thoracic array of scintillation detectors and two leg counters. Serial blood samples were also taken. The two exposure groups showed similar total deposition values (23 vs 26%) and the same biological retention halftimes, viz., 22.6 hr. When the retention data were corrected for blood-borne /sup 203/Pb, the biological halftimes for lung lead retention averaged 13.1 and ...
Potential exposure of workers to phosphide was examined during an in-depth industrial hygiene survey at the Bunge Corporation, in Kansas City, Kansas, where the gas was used as a grain fumigant. During the study, 14 men were employed at the facility. Tablets of aluminum phosphide were added to the grain mass for fumigation. General dilution ventilation resulted from outside air entering the work areas through ventilation louvers; there was also a local-exhaust ventilation system. Air samples revealed that, when the fumigant dispensers were being filled, workers in the area had significant exposure. At the time of the survey the relative humidity in the facility was high, permitting the reaction to phosphide to occur more readily. The levels of phosphide and respirable dust were reasonably low in the elevators, suggesting that the ventilation system was adequate. The author recommends that workers filling the dispenser with ...
An aerial radiological survey was conducted from August 10-16, 1993, over a 78-square-kilometer (30-square-mile) area of the Portsmouth Gaseous Diffusion Plant and surrounding area located near Portsmouth, Ohio. The survey was performed at a nominal altitude of 46 meters (150 feet) with a line spacing of 76 meters (250 feet). A contour map of the terrestrial gamma exposure rate extrapolated to 1 meter above ground level was prepared and overlaid on a set of United States Geological Survey topographic maps of the area and an aerial photograph of the plant. The terrestrial gamma exposure rates varied from about 7 to 14 microroentgens per hour at 1 meter above the ground. Protactinium-234m was observed at six sites within the boundaries of the plant. At a seventh site, only uranium-235 was observed. No other man-made, gamma ray-emitting radioactive material was present in a detectable quantity, either on or off the plant property. Soil ...
Preliminary psychometric properties of a new instrument, Angie/Andy Cartoon Trauma Scales (ACTS), are presented. Angie/Andy features a cartoon-based methodology, measuring trauma-related sequelae of prolonged, repeated abuse. A sample of 208 children comprised intrafamilial trauma, extrafamilial trauma, combined trauma, and nontrauma groups. Angie/Andy demonstrated high internal consistency, with coefficient alphas from 0.70 to 0.95. The three trauma groups scored significantly higher than the nontrauma group on all scales (p's < 0.0001). Generally, the most severely traumatized group scored significantly higher than the less severely traumatized groups. The number of types of violence exposures correlated with Angie/Andy scores from 0.55 to 0.74. The frequency and severity of trauma exposure correlated with Angie/Andy scores from 0.44 to 0.56. The Angie/Andy parent version correlated with a standardized parent scale ...
The general methods used to complete measurements of human exposures are identified and illustrations are provided for the cases of indirect and direct methods used for exposure analysis. The application...Full Text Available
This Waste Management Plant (WMP) for the Bear Creek Valley Treatability Study addresses waste management requirements for the Oak Ridge Y-12 Plant. The study is intended to produce treatment performance data required to design a treatment system for contaminated groundwater. The treatability study will consist of an evaluation of various treatment media including: continuous column tests, with up to six columns being employed to evaluate the performance of different media in the treatment of groundwater; an evaluation of the denitrifying capacity and metal uptake capacity of a wetland system; and the long-term denitrifying capacity and metal uptake capacity of algal mats. The Sampling and Analysis Plan (SAP) covers the project description, technical objectives, procedures, and planned work activities in greater detail. The Health and Safety Plan (HASP) addresses the health and safety concerns and requirements for the proposed sampling ...
By the use of thermoluminescence (TL) technique we have investigated the effects of gamma irradiation on the TL response of pulverised natural zircon (ZrSiO{sub 4}) crystals from the Jos Plateau area of Nigeria. Samples of the mineral that have been previously annealed were artificially irradiated to moderate gamma doses ranging from 0.7 to 4.9 Gy using {sup 60}Co gamma-source of the CERD. The natural TL glow curve of the sample showed a broad peak around 250 deg. C, the peak was however, found to be completely erased following heat treatment for 2 h at 400 deg. C. The TL glow curves of the artificially irradiated samples showed two overlapping glow peaks at about 112 deg. C (peak I) and at 156 deg. C (peak II) within the dose range utilised. We note that the natural TL peak appears to be different from the two observed in the artificially irradiated sample. The TL response with dose was investigated ...
By the use of thermoluminescence (TL) technique we have investigated the effects of gamma irradiation on the TL response of pulverised natural zircon (ZrSiO_4) crystals from the Jos Plateau area of Nigeria. Samples of the mineral that have been previously annealed were artificially irradiated to moderate gamma doses ranging from 0.7 to 4.9 Gy using "6"0Co gamma-source of the CERD. The natural TL glow curve of the sample showed a broad peak around 250 deg. C, the peak was however, found to be completely erased following heat treatment for 2 h at 400 deg. C. The TL glow curves of the artificially irradiated samples showed two overlapping glow peaks at about 112 deg. C (peak I) and at 156 deg. C (peak II) within the dose range utilised. We note that the natural TL peak appears to be different from the two observed in the artificially irradiated sample. The TL response with dose was investigated for the two ...
This paper describes an experiment which has been performed with a somewhat different philosophy in its approach as compared to previous work. (a) The trigger threshold energy was increased by more than a factor of ten on previous experiments reducing the dilution effect of many lower energy showers known not to produce tachyons. 1673 shower were recorded. (b) The exposure time was made longer than previous experiments in order to obtain a reasonably large statistical sample at the higher threshold. Observations were made between February 1979 and June 1980, the total live time being 9768 hours. (c) Records of the detector output amplitude for the 480#mu#s lead time were integrated point by point as is sometimes done in radio astronomy, this gives the integrated energy deposition within the detector.
The radiation control carried out in Atomic Energy Research Institute, Kinki University, for the reactor installation and the tracer/accelerator facilities from April, 1981, to March, 1982, is described. The reactor was operated for total 1057.1 hours at the maximum heat output of 1 W. The persons subject to radiation protection as of April, 1981, were 126 persons in all, including 23 in radiation work and 11 in X-ray work, etc. The contents of this report are as follows: personnel monitoring (health examination, the control of individual exposure dose); laboratory monitoring (the measurement of area dose rate, radioactive concentration in air and water, and surface contamination density); field monitoring (environmental ..gamma..-ray dose rate, radioactive concentration in environmental samples); the use of unsealed radioisotopes, etc.
Thermoluminescence of inorganic dust extract from herbs and spices has been demonstrated to be a useful method to discriminate irradiated food products as well as to estimate the total dose exposure. The time evolution of infrared stimulated luminescence has been systematically investigated in potassium feldspar and albite minerals subjected to different doses of gamma irradiation (ranging from 0 to 8 kGy). Experimental results reveal a 300-600 nm signal which is greatly intensified for irradiated samples, following the same irradiation dose dependence observed in thermoluminescence. The luminescence intensity disappears after few seconds of illumination, following a time evolution which is proportional to (1 + Bt){sup -P}. The influence of both B and P factors upon the irradiation dose has been systematically analysed. (author)
Thermoluminescence of inorganic dust extract from herbs and spices has been demonstrated to be a useful method to discriminate irradiated food products as well as to estimate the total dose exposure. The time evolution of infrared stimulated luminescence has been systematically investigated in potassium feldspar and albite minerals subjected to different doses of gamma irradiation (ranging from 0 to 8 kGy). Experimental results reveal a 300-600 nm signal which is greatly intensified for irradiated samples, following the same irradiation dose dependence observed in thermoluminescence. The luminescence intensity disappears after few seconds of illumination, following a time evolution which is proportional to (1 + Bt)"-"P. The influence of both B and P factors upon the irradiation dose has been systematically analysed. (author)
The occurrence of persistent organochlorine pesticides (OCPs) in breast milk samples collected from mothers from twelve provinces in mainland China was investigated. Dichlorodiphenyltrichloroethanes (DDTs) were the most prevalent agent, followed by HCHs and HCB, whereas levels of chlordane compounds, drins and mirex were lower. The relatively lower DDE/DDT ratio in the Fujian rural area suggested more recent exposure to DDT than in other areas. The mean level of DDTs in breast milk from the southern China was higher than those from northern China (p < 0.05). A positive correlation was observed between concentration of DDTs in human milk and consumption of animal-origin food, suggesting that this parameter could play an important part in influencing OCPs burdens in lactating women. The mean...
Systematically review risks of an infant being born with low birth weight (LBW), preterm birth (PTB) or small for gestational age (SGA) among married and unmarried women. Medline, Embase, CINAHL, and bibliographies of identified articles were searched for English language studies. Studies reporting birth outcomes of married and unmarried (single and cohabitant) were included. Two reviewers independently collected data and assessed the quality of the studies for biases in sample selection, exposure assessment, confounder, analytical, outcome assessments, and attrition. Meta-analyses were performed using random effect model for both unadjusted and adjusted data and odds ratio (OR), and 95% confidence interval (CI) were calculated. Twenty-one studies of low to moderate risk of bias were inclu...
Flow cytometric techniques were used to measure the cytological and biochemical damage to respiratory tract cells in animals exposed to particulates. Hamsters were exposed to raw and spent oil shale particulates and silica by intratracheal instillation. Exfoliated lung cells were obtained by sacrificing the animals and lavaging the respiratory tract posterior to the trachea with saline. Cell samples were fixed in ethanol and stained with mithramycin for fluorescence analysis of DNA content. DNA content distributions from hamsters exposed to spent oil shale and silica particulates showed atypical changes 28 to 35 days later. Cell counts and total numbers of macrophages, leukocytes, and epithelial cells in the lavage fluid also showed marked changes related to time after exposure.
Inputs on radiological conditions forms the basis of implementation of effective exposure control to plant personnel in nuclear power station. Radiation monitoring system provides this input to the plant operator as well as to health physics group. Several design modifications have been incorporated in the Radiation Monitoring System at Tarapur Atomic Power Station (TAPS 3 and 4) over the similar systems at Kakrapar Atomic Power Station (KAPS) and Kaiga Generating Station (KGS). The radiological monitoring systems installed at TAPS unit 3 and 4 includes on line Radiation Data Acquisition System (RADAS), Emergency sampling system, effluent monitoring system and environmental monitoring system. The design changes and the versatile use of these systems are presented in this paper. (author)
We report about the fabrication and analysis of the properties of Cr/CrO_x/Cr tunnel junctions and SET transistors, prepared by different variants of direct-writing multilayer technique. In all cases, the CrO_x tunnel barriers were formed in air under ambient conditions. From the experiments on single junctions, values for the effective barrier height and thickness were derived. For the Cr/CrO_x/Cr SET transistors we achieved minimal junction areas of 17 x 60 nm^2 using a scanning transmission electron microscope for the e-beam exposure on Si_3N_4 membrane substrate. We discuss the electrical performance of the transistor samples as well as their noise behavior.
Several proposals have been made on the method of calculating generation of formaldehyde released from plywood. In calculating generation per hour of a volatile organic compound of adhesives or coatings using a chamber method, such models are frequently used that the generation is largest when the specimen is exposed in the chamber and that the generation attenuates with lapse of time. In the meantime, a number of studies for calculating formaldehyde generation from construction materials are often those determining a specific quantity of generation in a stationary state, while few studies are the observation of time series variation from immediately after the exposure into the chamber. Accordingly, the subject studies used lauan plywood as the samples and examined the method of calculating the change with lapse of time of the formaldehyde generation. (translated by NEDO)
Air flow rates and carbon dioxide concentrations of air entering and exiting eight H-Area waste tanks were monitored for a period of one year. The average instanteous concentration of carbon dioxide in air is within the range reported offsite, and therefore is not affect by operation of the coal-fired power plant adjacent to the tank farm. Waste solutions in each of the tanks were observed to be continuously absorbing carbon dioxide. The rate of absorption of carbon dioxide decreased linearly with the pH of the solution. Personnel exposure associated with the routine sampling and analysis of radioactive wastes stored at SRP to determine the levels of corrosion inhibitors in solution could be reduced by monitoring the absorption of carbon dioxide and using the relationship between pH and carbon dioxide absorption to determine the free hydroxide concentration in solution.
Among in uterus exposed A-bomb survivors, fetal week is the most important factor to clarify the effects of A-bomb radiation on developmental process of the fetal brain. The study population of in utero exposed A-bomb survivors has first been established in 1953 in Hiroshima and in 1955 in Nagasaki. According to the estimated DS86 uterus absorption doses, fetal absorption doses obtained from the uterus doses, and intelligence quotient. Various studies on brain damage, including microcephaly, have been undertaken among in uterus exposed A-bomb survivors. Brain development has been shown to be affected during the fetal weeks 8-15 and 16-25. A review of the literature has revealed that 80% of the children with mental retardation and 15 of 18 cases of microcephaly (83%) were exposed in utero during the fetal week 8-15. Among children exposed at the fetal weeks 8-15 and 16-25, average learning was significantly decreased. The incidence of spasm was highest among ...
A series of experiments were carried out to examine the resistant capacity of a chemically treated hard wood, Anthocephalus cadamba (Roxb) Miq. to thermal and termite degradation. The treatment with thermosetting resins viz. urea formaldehyde (UF), melamine formaldehyde (MF) and phenol formaldehyde (PF) at 31-33 levels of weight percent gain (WPG) increased the strength property i.e. modulus of rupture (MOR) by 7.50-21.02% and stiffness i.e. modulus of elasticity (MOE) by 9.50-12.18% over the untreated one with no remarkable effect on specific gravity. The treated samples were found resistant to termite attack, while the untreated one was badly damaged by termites on 12 months' exposure to a termite colony. The thermal degradations of untreated and treated wood samples were studied using thermogravimetric (TGA) and differential thermogravimetric (DTG) techniques at heating rates 20 and 30 {sup o}Cmin{sup -1} in ...
Gas-insulated systems employing SF/sub 6/ are utilized in a variety of applications in power delivery systems. Because electric arcs, sparks or corona can decompose SF/sub 6/ into by-products having chemical properties different from SF/sub 6/, environmental concerns arise regarding inadvertent human exposures to electrically-decomposed SF/sub 6/. Biological assays in our laboratory using mammalian cell culture systems have revealed that SF/sub 6/, spark-decomposed under specific experimental conditions, can produce cell death. Chemical analysis of spark-decomposed SF/sub 6/ has identified the major decomposition pathways and by-products. Biological testing of individual by-products or by-product mixtures has indicated that these major decomposition products may not account for the majority of the cell killing effects seen in our assays. Further experiments have suggested that S/sub 2/F/sub 10/ may be produced and accumulate under our specific decomposition ...
This study presents the findings of radiometric analysis carried out to determine the activity concentrations of natural radionuclides in raw materials (clay, kaolin, quartz, feldspar, dolomite, alumina, bauxite, zirconium minerals, red mud and frit) and end products (glazed ceramic wall and floor tiles) in the Turkish ceramics industry. Hundred forty-six samples were obtained from various manufacturers and suppliers throughout the country and analyzed using gamma-ray spectrometer with HPGe detectors. Radiological parameters such as radium equivalent activity, activity concentration index and alpha index were calculated to assess the radiological aspects of the use of the ceramic end products as decorative or covering materials in construction sector. Results obtained were examined in the light of the relevant national and international legislation and guidance and compared with the results of similar studies reported in different countries. The results suggest ...
Previous behavioral and pharmacological studies have implicated endorphins in radiation-induced locomotor hyperactivity of the C57BL/6J mouse. However, the endogenous opiate(s) responsible for this behavioral change have not been identified. The present study measured beta-endorphin-like immunoreactivity (beta-END-LI) in brain, blood, and combined brain and pituitary samples from irradiated and sham-irradiated C57BL/6J mice. After radiation exposure, levels of beta-END-LI decreased significantly in the brain. A similar, but not statistically significant, decline was measured in combined brain and pituitary samples. Concentrations of blood beta-END-LI were not changed by irradiation. These radiogenic changes in beta-END-LI are in some ways similar to those observed after other stresses. However, radiation-induced locomotor hyperactivity may be mediated more by alterations of beta-END-LI in the brain than in the periphery. ...
The transport properties of a 'thin' polycrystalline diamond film are analyzed after the sampleexposure to 8.06-keV x-ray radiation. Structure and morphology of the as-grown film have been evaluated by Raman, x-ray diffraction, and scanning electron microscopy techniques. The transport properties have been investigated by measuring dark current-voltage characteristics in the temperature range of 60 to 360 K. Ohmic transport has been evidenced on the as-grown film up to 1.16x10"5 V/cm. After irradiation, nonlinear contributions to the dark current have been evidenced and related to field-assisted thermal ionization of traps. Below 200 K, hopping mechanisms have been observed. Correlations have been found among x-ray irradiation, density of traps involved in the transport processes, and the nonhomogeneous nature of the sample. A simple model of the grain boundary structure is proposed to explain the observations.
Natural radioactive materials under certain conditions can reach hazardous radiological levels. The natural radionuclide ({sup 238}U, {sup 232}Th, {sup 40}K) contents of rock samples at various locations in the North Tushki area were investigated using gamma-spectrometric analysis. Estimates of the measured radionuclide content have been made for the absorbed dose rate of gamma radiation. The equivalent radium (R{sub eq}) and the external hazard index (H{sub ex}) which resulted from the natural radionuclides in soil are also calculated and tabulated. The studied samples have been collected from various rock exposures in the North Tushki area. The distribution of major oxides, U and Th were studied. It is found that the enrichment and depletion of the major oxides are mainly due to the effect of hydrothermal alteration, which caused mobility of some major oxides, which increases some elements and decreases others. It is ...
We present deep two-dimensional spectra of 22 candidate and confirmed Lyman break galaxies (LBGs) at redshifts 2exposure times ranged from 10 to 50 ks. We measure redshifts, some new, ranging from z=0.2072 to z=4.056, including two interlopers at z<1, and resulting in a sample of 14 LBGs with a median redshift z=2.424. The morphologies and kinematics of the close pairs and multiple knot sources in our sample are generally inconsistent with galaxy formation scenarios postulating that LBGs occur only at the bottom of the potential wells of massive host halos; rather, they support ...
Bremstrahlung Isochromat Spectroscopy (BIS). The XES spectra were collected using a Specs electron gun for the excitation and the XES 350 grating monochromator and channel plate system from Scienta as the photon detection. Spectra were collected in 'normal mode,' where the electron gun kinetic energy (KE) and the energy position of the center of the channel plate were both fixed and the energy distribution in the photon (hv) spectrum was derived from the intensities distributed across the channel plate detector in the energy dispersal direction. The polycrystalline Ce sample was oxidized by exposure to air at ambient pressures. After introduction to the ultra-high vacuum system, the oxidized sample was bombarded with Ar, to clean the topmost surface region and stabilize the surface and near surface regions. Although CeO{sub 2} would be the thermodynamically preferred composition in an oxygen rich ...
Electrodeposited Zn alloys with Fe group metals are known to be more resistant than pure Zn. However, the role of the corrosion products on the corrosion inhibition is not considered up to date. The aim of the present work was to examine the composition of corrosion products, which form on the Zn and Zn alloy surfaces under atmospheric corrosion conditions up to 3 year of exposure, trying to correlate it with the differences in their corrosion resistance. Zn corrosion products have been characterized by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Corrosion film composition was determined to depend on the sampleexposure she, as well on the coating type. During the initial exposure stages oxide film was found to be the principal reaction product (XPS data), which in marine station consists from hydroxide phase exceptionally, while in urban one, contain up to 6-12 % of oxide. ...
Nowadays there is a growing interest in the study of natural radioactivity levels, mainly of radionuclides; {sup 238}U, {sup 226}Ra, {sup 232}Th, {sup 40}K, and {sup 210}Pb present in the environment. The environmental radioactivity control is very important to obtain information on exposure of humans and vegetables to potential sources on natural radioactive occurrences. Industrial processes involving mining and extraction and production of oil foster concentration of radionuclides, contributing to the occurrence of what is known as 'TENORM' - Technologically Enhanced Naturally Occurring Radioactive Material. This work aims to assess the environmental radiological impact on the estuarine area of the Industrial Park of SUAPE, due the installation of an oil refinery and the consequent introduction on the environment of natural radioactive materials from other regions in that area. The radioisotopes {sup 238}U, {sup 226}Ra, {sup 232}Th , {sup 40}K ...
Full text: This presentation will review the progress achieved so far by the Irish national regulatory agency, the Radiological Protection Institut e of Ireland (R.P.I.I.) in the investigation of work activities where the presence of natural radiation sources (NORM) could lead to a significant increase in exposure to workers or members of the public which cannot be disregarded from the radiation protection point of view. Since the coming into force in Ma y 2000 of the Radiological Protection Act, 1991 (Ionising Radiation) Order, 2000 (S.I. No. 125 of 2000) which implements the Eu B.S.S. Directive 96/29/EURATOM, four major NORM industries currently active in Ireland have been investigated. According to the literature, they are all considered liable to involve work practices resulting in exposure to NORM. They include: the gas extraction and production industry, the peat- and coal-firing power generation industry and the bauxite/alumina refining ...
An average of 9 million gallons per day of oil-contaminated ballast water off loaded from tankers are treated at the Alyeska Pipeline Service Company Ballast Water Treatment Facility at the terminus of the Trans-Alaska Pipeline in Port Valdez, Alaska. This paper focuses on the results of 2 Prince William Sound Regional Citizens' Advisory Council monitoring programs which detail changes in the chemical composition of treated ballast water as it moves from tankers through the facility and subsequently traces the effluent hydrocarbons into the receiving environment of Port Valdez. The treatment facility involves gravity separation tanks, dissolved air flotation cells and biological treatment tanks. Effluent containing traces of volatile aromatics, including benzene, toluene, ethylbenzene and xylenes, low levels of oil, saturated hydrocarbons and polycyclic aromatic hydrocarbons is being continuously discharged to Port Valdez. Because of the extremely large average flow rate, low ...
Manganese is an essential metal of toxicologic concern primarily because of exposure via inhalation. Environmental forms of Mn exist mainly as insoluble oxides, yet much of the research information available relates to the soluble salts. In the present study, adult male Sprague-Dawley rats were intratracheally instilled with either soluble MnCl/sub 2/ or insoluble Mn/sub 3/O/sub 4/ labeled with /sup 54/Mn. Lungs and other major organs were sampled over a span of 3 mo after dosing with the respective chemicals, which were equivalent to 8 ..mu..Ci and 1 ..mu..mol of manganese in 0.2 ml of buffer. There was rapid clearance of Mn from the lungs in the case of both chemicals; the chloride cleared at an initial rate of nearly four times that of the oxide. Despite this early difference, the amount of /sup 54/Mn remaining in the lungs after 2 wk was similar for both compounds. The level of /sup 54/Mn in the liver, kidney, spleen, and testes peaked at ...
In 1959, the Test Manager's Committee to Establish Fallout Doses calculated estimated external gamma exposure at populated locations based upon measurements of external gamma-exposure rate. Using these calculations and estimates of population, we have tabulated the collective estimated external gamma exposures for communities within established fallout patterns. The total collective estimated external gamma exposure is 85,000 person-R. The greatest collective exposures occurred in three general areas: Saint George, Utah; Ely, Nevada; and Las Vegas, Nevada. Three events, HARRY (May 19, 1953), BEE (March 22, 1955), and SMOKY (August 31, 1957), accounted for over half of the total collective estimated external gamma exposure. The bases of the calculational models for external gamma exposure of ''infinite ...
Objective: To investigate the relationship between exposure dose and image quality for a direct digital radiography system and to determine the optimum exposure parameters for pelvic examination. Methods: A contrast-detail phantom CDRAD2.0 was exposed to different doses and the IQF of phantom images were calculated. The optimum exposure parameters were determined by ANOVA and SNK analysis. The image of an anthropomorphic phantom taken with optimized exposure parameters was verified using CEC image criteria. Results: The IQF of the images of CDRAD2.0 phantom was significantly different for different doses, as the exposure dose was greater than 0.61 mGy. The IQFs have no difference for different dose groups. The image quality between this optimized exposure dose and conventional exposure dose not was significantly different. Conclusion: The ...
The purpose of this study was to assess the effect of a 735-kV transmission line on the electric and magnetic field exposures of people living at the edge of the line's right of way. Exposure of 18...Full Text Available
OBJECTIVE--The study was performed to examine the influence of the exposure to magnetic fields in the potrooms of an electrolysis plant on the occurrence of musculoskeletal symptoms among the employees....Full Text Available
Reports in humans and rodents indicate that immune development may be altered following perinatal exposure to immunotoxic compounds, including chemotherapeutics, corticosteroids, polycyclic hydrocarbons,...Full Text Available
Exposure of female rats to trichloroethylene (TCE), an environmental toxicant commonly found in ground and surface waters throughout the United States, reduces the fertilizability of oocytes...Full Text Available
Strategies are needed for assessing the risks of exposures to airborne toxicants that vary over concentrations and durations. The goal of this project was to describe the relationship between the concentration...Full Text Available
Antimony toxicity occurs either due to occupational exposure or during therapy. Occupational exposure may cause respiratory irritation, pneumoconiosis, antimony spots on the skin and gastrointestinal...Full Text Available
The genetically significant dose (GSD), per Caput mean bone marrow dose (CMD), leukemia significant dose (LSD) and malignancy significant dose (MSD) from medical diagnostic X-ray examinations in Japan were estimated based on a 1979 nationwide survey of randomly sampled hospitals and clinics. The population risk estimates were carried out using the resultant values of GSD, LSD and MSD. In the risk estimates, the significant factors, namely, the relative child expectancy, the leukemia significant factor and the malignancy significant factor, for patients were assumed to be same as those of general population. The risk factors used were 185 x 10"-"6 rad"-"1 for genetic risk of all generations, 20 x 10"-"6 rad"-"1 for fatal leukemia and 165 x 10"-"6 rad"-"1 for fatal malignant diseases, respectively. The resultant annual population doses per person were 15 mrad (0.15 mGy) for GSD, 107 mrad (1.07 mGy) for CMD, 86 mrad (0.86 mGy) for LSD and 43 mrad (0.43 mGy) for MSD, ...
We have studied the correlation between the chemical state and the oxygen-sensing properties of an iron oxide thin film using a setup that allows simultaneous sensor resistance measurements and X-ray photoelectron spectroscopy (XPS) data acquisition. The gas exposures were performed at the highest operating pressure of the XPS spectrometer at a controlled sample temperature which allows direct comparison between the sensor response and the chemical state of the surface. The iron oxide film was modified by a sequence of argon ion sputtering steps and the induced changes in the chemical state, resistance, and sensitivity to oxygen were investigated. The sputtering was found to reduce the iron from the Fe"3"+ to the Fe"2"+ state and to decrease the sensor resistance. The measured sensitivity to oxygen first increased by a factor of two but then collapsed to its original level. The mechanism for oxygen sensing was found to be filling of the oxygen ...
Austenitic stainless steels have been implanted with molybdenum ions (Mo[sup +], 100 keV, 2.5 x 10[sup 16] atoms cm[sup -2]). The implanted material has been characterized by XPS and RBS. The implanted region has a thickness of [approx] 1000 A with a maximum molybdenum concentration of [approx] 9 at.% Mo located at [approx] 210 A from the surface. The effects of implanted molybdenum on the passivation of the alloy in 0.5 M H[sub 2]SO[sub 4] have been investigated by electrochemistry and XPS. After XPS analysis the samples were transferred without exposure to air into a glove-box with an inert atmosphere. The electrochemical behaviour of the alloy is significantly modified by the implanted molybdenum. The major effect is that the activation peak disappears. A bilayer structure (outer hydroxide/inner oxide) of the passive film is observed for both the implanted and non-implanted alloys and the thicknesses of the films are similar. On the ...
Austenitic stainless steels have been implanted with molybdenum ions (Mo"+, 100 keV, 2.5 x 10"1"6 atoms cm"-"2). The implanted material has been characterized by XPS and RBS. The implanted region has a thickness of #approx# 1000 A with a maximum molybdenum concentration of #approx# 9 at.% Mo located at #approx# 210 A from the surface. The effects of implanted molybdenum on the passivation of the alloy in 0.5 M H_2SO_4 have been investigated by electrochemistry and XPS. After XPS analysis the samples were transferred without exposure to air into a glove-box with an inert atmosphere. The electrochemical behaviour of the alloy is significantly modified by the implanted molybdenum. The major effect is that the activation peak disappears. A bilayer structure (outer hydroxide/inner oxide) of the passive film is observed for both the implanted and non-implanted alloys and the thicknesses of the films are similar. On the implanted alloy the outer ...
The aim of this research work has been the estimation of the stochastic risk for five barium examinations. The sample was the population attending the Radiological Service of the 'Nuestra Senora de la Victoria' University Hospital, who had been treated with some barium examinations, set in five different groups: oesophagus tract, oesophagus-gastric-duodenal tract, intestinal tract, enteroclysis and double enema. To estimate the stochastic risk, it is necessary to know the organ dose. This can be calculated from the dose-area product which allows us to determine the effective dose using software. The dose-area product is the most suitable quantity to measure in these types of examination. We have evaluated the contribution that each procedure provides to the genetically significant dose, somatically significant dose, collective effective dose, annual effective dose 'per capita' and detriment, which are useful for assessing the population risk of cancer or hereditary ...
Various nylons including nylon 6, nylon 66, nylon 610 and nylon 12 in the forms of fiber and film were irradiated with the gamma-ray from Co-60 at the dose rate of 0.12 Mrad/hr in the atmosphere of oxygen at 7 kg/cm/sup 2/ and at the room temperature. The irradiation in vacuum on the same specimens was performed at 0.5 Mrad/hr. The tensile properties and the gel fraction of the irradiated nylon samples were measured, and the radiation resistance of the nylons against the irradiation at low dose rate was estimated. From the experimental results, it became clear that in the case of irradiation in vacuum, all the nylons were durable to the irradiation of 250 Mrad or more, and nylon 6 was more durable than nylon 12, and in the case of irradiation in pressurized oxygen, the radiation resistance of the nylons decreased to one-tenth as compared with that in vacuum, and contrary to that in vacuum, nylon 12 was superior to nylon 6, while nylon 610 was intermediate. From ...
Plutonium metal is produced by reducing PuF{sub 4} prepared from PuO{sub 2} by fluorination. Both fluorination and reduction are batch processes at the Los Alamos Plutonium Facility. The conversion of plutonium oxide to fluoride greatly increases the neutron yield, a result of the high cross section for alpha-neutron ({alpha},n) reactions on fluorine targets compared to the (more than 100 times) smaller {alpha},n yield on oxygen targets. Because of the increase, total neutron counting can be used to monitor the conversion process. This monitoring ability can lead to an improved metal product, reduced scrap for recycle, waste reduction, minimized reagent usage, and reduce personnel radiation exposures. A new stirred-bed fluorination process has been developed simultaneously with a recent evaluation of an automated neutron-counting instrument for quantitative process monitoring. Neutrons are counted with polyethylene-moderated {sup 3}He-gas proportional counters. ...
A nation-wide survey of natural radioactivity in building materials was conducted during 1982-1984. Samples including industrial wastes, by-products and common building materials were collected from main building material manufactories in 29 provinces except Taiwan. The results of exposure rates, specific activities and release rate for "2"2"2Rn are presented. The specific activities of common materials are listed in declining order as follows: clay bricks > common concrete and sandstones > limes and ordinary cement. The highest level was found in breeze bricks made of stone coal, phosphogypsum and red mud with high intrinsic radioactivity. Therefore, these raw materials should be strictly controlled in manufacturing building materials. The measurement results also showed that the typical specific activities of common building materials in our country were "2"2"6Ra 50 Bq/kg, "2"3"2Th 50 Bq/kg and "4"0K 500 Bq/kg. Based on the surveyed ...
Using the advantage that the projected range of ions in matter is sharply limited, a new technique for the production of three-dimensional microstructures has been developed. Based on the P-LIGA technique (Proton-Lithographie, Galvanoformung, Abformung) this process allows the generation of structures with surfaces of almost any shape having a root mean square roughness of about #lambda#/50 for visible light wavelengths. An ion beam with diameters between 2 and 50 #mu#m is directly writing the structures and the shape is varied by geometrical manipulation of the sample in three axes during the exposure. Practically, structures have been written using protons with an energy of 1.8 MeV in a provisional experimental setup with beam diameters of 10 and 50 #mu#m, respectively. After irradiation, the parts exposed were dissolved in a liquid developer without affecting the nonirradiated parts. The shape and the rms roughness of the resulting ...
Sheep red blood cells (SRBCs) were labelled with a concanavalin A-luminol-bovine serum albumin conjugate specific for the transmembrane anion transport protein (Band 3) and exposed to 2450-MHz continuous-wave microwave radiation at an average specific absorption rate of 91W/kg for 10 min. The temperature was held constant at 25, 37, 40, 42, or 45C with an airflow heat-exchange system. Following exposure to microwave or air heating, the decrease in residual base-activated chemiluminescence (CL) of the SRBCs was measured as an indication of infield oxidase activity. Air heating resulted in a significant decrease in residual CL at temperatures above 37C (74% decrease at 45C). Microwave radiation inhibited the decline in residual CL above 37C. At 45C the inhibition was 40%. The results suggest microwave radiation either reversibly altered the thermodynamics of oxygen binding to haemoglobin or failed to energize a significant portion of the haemoglobin molecules in each ...
The identification of crystallographic phases in the scanning electron microscope (SEM) has been limited by the lack of a simple way to obtain electron diffraction data of an unknown while observing the micro structure of the specimen. With the development of Charge Coupled Device (CCD) based detectors, backscattered electron Kikuchi patterns (BEKP), alternately referred to as electron backscattered diffraction patterns (EBSP), can be easily collected. Previously, BEKP has been limited to crystallographic orientation studies due to the poor pattern quality collected with video rate detector systems. With CCD detectors, a typical BEKP can now be acquired from a micron or sub-micron-sized crystal using an exposure time of 1-10 seconds with an accelerating voltage of 10-40 kV and a beam current as low as 0.1 nA. Crystallographic phase analysis using BEKP is unique in that the properly equipped SEM permits high magnification images, BEKP`s, and elemental information to ...
Measurements of the Kapitza conductance to liquid helium II across the (100) surface of single crystals of copper are presented. The temperature range of these measurements was 1.6-- 2.1 K. The sample surfaces were subjected to several different treatments. Some surfaces were cleaned by low-energy argon ion bombardment, annealed in an ultrahigh-vacuum system, and preserved under vacuum until purified liquid helium was admitted. Other surfaces were intentionally damaged by machining and/or exposure to the atmosphere. The conductance after these latter treatments was found to be about a factor of three higher than that of the more ideally cleaned and annealed surfaces, and a significant difference in the temperature dependence of the conductance was also observed. Conductances were reproducible for similarly treated surfaces and correlated with surface damage determined by x-ray diffraction. The relationship of these results to the numerous ...
Xenotropic murine leukemia virus-related virus (XMRV) was discovered in human prostate tumors and later in some chronic fatigue syndrome (CFS) patients. However, subsequent studies have identified various sources of potential contamination with XMRV and other murine leukemia virus (MLV)-related sequences in test samples. Biological and nucleotide sequence analysis indicates that XMRV is distinct from known xenotropic MLVs and has a broad host range and cell tropism including human cells. Therefore, it is prudent to minimize the risk of human exposure to infection by evaluating XMRV contamination in cell lines handled in laboratory research and particularly those used in the manufacture of biological products. Nested DNA PCR assays were optimized for investigating XMRV gag and env sequences in various cell lines, which included MRC-5, Vero, HEK-293, MDCK, HeLa, and A549, that may be used in the development of some vaccines and other cell lines ...
The resolution of X-ray diffraction microscopy is limited by the maximum dose that can be delivered prior to sample damage. In the proposed Serial Crystallography method, the damage problem is addressed by distributing the total dose over many identical hydrated macromolecules running continuously in a single-file train across a continuous X-ray beam, and resolution is then limited only by the available molecular and X-ray fluxes and molecular alignment. Orientation of the diffracting molecules is achieved by laser alignment. We evaluate the incident X-ray fluence (energy/area) required to obtain a given resolution from (1) an analytical model, giving the count rate at the maximum scattering angle for a model protein, (2) explicit simulation of diffraction patterns for a GroEL-GroES protein complex, and (3) the frequency cut off of the transfer function following iterative solution of the phase problem, and reconstruction of an electron density map in the ...
Biomonitoring of human populations for exposure to genotoxic/clastogenic agents in the environment or the workplace must depend upon statistical tests for elevations in the frequencies of the biological endpoints being monitored, usually chromosomal aberrations (CA), micronuclei (MN), or sister chromatid exchanges (SCE) in peripheral blood lymphocytes. Statistical tests are based, in turn, upon certain assumptions regarding the distribution of the test statistic. When they are often not recognized as such, tests of significance can be in error, and any conclusion drawn that there is or is not a statistically significant difference between one population sample and another maybe erroneous. In population monitoring this means either false negatives or false positives can result and it is hard to know which is worse. Furthermore, even the intelligent design of studies whose object is to test for an elevated level in an exposed population must ...
Radiotherapy with high-energy carbon ion beams can be more advantageous compared to photons because of better physical dose distribution and higher biological efficiency in tumour cell sterilization. Despite enhanced normal tissue sparing, damage incurred by normal cells at the beam entrance is unavoidable and may affect the progeny of surviving cells in the form of inheritable cytogenetic alterations. Furthermore, the quality of the beam along the Bragg curve is modified by nuclear fragmentation of projectile and target nuclei in the body. We present an experimental approach based on the use of a polymethylmethacrylate (PMMA) phantom that allows the simultaneous exposure to a particle beam of several biological samples positioned at various depths along the beam path. The device was used to measure the biological effectiveness of a 60 MeV/amu carbon-ion beam at inducing chromosomal aberrations in G{sub 0}-human peripheral blood lymphocytes. ...
Current regulations guiding technical aspects of natural resource damage assessments combine source, exposure pathway, resource injury, and monetary damage components. In order to associate any observed injury to the uncontrolled release of chemicals (e.g. oil spills, contaminated sediments, in-place toxics, etc.), it is important to link the chemical ''release'' to the injured resource. In complex environmental settings where multiple sources of similar chemicals are combined, multicomponent chemical methods must be used to link the release to the environmental distribution of chemicals. Three examples of the utility of multicomponent organic chemical analyses linked to comprehensive and representative sampling strategies will be discussed--the Shell Martinez Refinery oil spill, the Exxon Valdez oil spill, and a contaminated sediment assessment. These NRDA-based source identifications are based on use of polycyclic aromatic hydrocarbons, ...
Careful sample preparation and secondary ion mass spectroscopy have been used to characterize arsenic dose loss to the silicon-oxide interface. Using high resolution x-ray photoelectron spectroscopy for microprofiling, we have directly observed the pileup of arsenic at the silicon dioxide-silicon interface. At least half of the pileup is shown to be on the silicon side of the interface in the first monolayer of silicon. Monolayer chemical oxidation and etching are successfully used to profile this pileup in silicon. This pileup contains most of the arsenic dose loss that occurs during transient enhanced diffusion. This result is crucial to correctly model the dose loss and provides physical justification for using a trap/detrap model at the interface, which is necessary to account for the fact that the arsenic surface concentration remains constant during an anneal and the fact that the dose loss is partially reversible. Finally, we have found that normal etching ...
Careful sample preparation and secondary ion mass spectroscopy have been used to characterize arsenic dose loss to the silicon-oxide interface. Using high resolution x-ray photoelectron spectroscopy for microprofiling, we have directly observed the pileup of arsenic at the silicon dioxide-silicon interface. At least half of the pileup is shown to be on the silicon side of the interface in the first monolayer of silicon. Monolayer chemical oxidation and etching are successfully used to profile this pileup in silicon. This pileup contains most of the arsenic dose loss that occurs during transient enhanced diffusion. This result is crucial to correctly model the dose loss and provides physical justification for using a trap/detrap model at the interface, which is necessary to account for the fact that the arsenic surface concentration remains constant during an anneal and the fact that the dose loss is partially reversible. Finally, we have found that normal etching ...
In situ toxicity tests were designed for Ceriodaphnia dubia and Chironomus tentans as part of a larger study designed to assess the effectiveness of constructed wetlands for the treatment of wastewater produced by oil production at Suncor OSG. The artificial wetlands were 50m long by 3m wide, with three replicates of the control and the treatment. Each wetland had four sample sites equidistant along its length, creating a gradient of treatment from site A being the most toxic to site D being the least toxic. Each test was conducted twice during the summer of 1994. Both the Ceriodaphnia and Chironomus test cages were a flow through design to allow for maximal exposure to the water within the wetlands. Mortality and reproduction were used as endpoints for Ceriodaphnia, whereas mortality and growth were used as endpoints for the Chironomus test. Test durations were fifteen and ten days respectively. Chironomus had very high mortality along the ...
Limestone-based sorbents are used extensively in utility boilers and tail-gas desulfurization units to remove sulfur oxides formed during the combustion of fossil fuels. Such units generate {approximately}20 million tons of flue-gas desulfurization (FGD) wastes in the U.S. annually, the bulk of which ({approximately}95%) are discarded in landfills or holding ponds. However, a significant portion of the Ca in these materials is not sulfated (remains as CaO or Ca(OH){sub 2}), particularly in units that generate dry wastes. When hydrated, such wastes exhibit a strong affinity to absorb acid gases at ambient temperature. This study represents a continuation of previously reported CO{sub 2}-absorption studies and includes more recent work on the absorption of H{sub 2}S and NO. Ten FGD-waste samples along with a control fly ash were examined. Absorption capacities, the role of available calcium and particle size, and mineralogic changes in the wastes following ...
This human investigation of lead absorption from the lungs utilized two forms of lead, lead chloride and lead hydroxide; the former was used in picogram amounts and the latter at microgram levels. These two species of lead were selected in an attempt to simulate the range of physicochemical properties found in atmospheric lead (urban air). Aerosols labeled with lead-203 were made of comparable aerodynamic size (MMAD 0.25 ..mu..m +- 0.1) by using sodium chloride as the deposition-determining aerosol. After brief, mouthpiece exposures, 17 subjects were followed by serial counting with a thoracic array of 12 2-in. scintillation detectors and two 2-in. leg counters, all coupled to single channel analyzers. Serial blood samples were also taken. The two exposure groups showed similar total deposition values (23 vs 26%) and the same biological retention halftimes, viz., 22.6 h. When the retention data were corrected for ...
A technique involving shifting of core fuel loadings was investigated as a method for reducing the neutron flux at points of high damage accumulation in the pressure vessel wall of a light water reactor. Calculations were run for six types of commercial generic PWR. Information is provided on the progress being made to develop and apply the Solid State Track Recorder (SSTR) method for in-situ in- and ex-vessel measurements of neutron exposure parameter values, such as fluence (E > 1.0 MeV) and dpa in iron. A new technique of quantitative track counting, the Buffon needle method, is advanced. It is based on random sampling of the SSTR surface. A desensitized etching technique was developed that resulted in an excellent differential energy response for alpha particles in the 3- to 14-MeV energy range. The optical efficiency of Muscovite mica for manual fission track counting is being redetermined to form a data base for comparison with ...
Thermoluminescence (TL) and Electron Paramagnetic Resonance (EPR) dosimetry were used to measure dose effects in borosilicate glass with time, from 10 minutes to #approx#60 days following exposure to a dose of up to 10,000 Rad. TL and EPR results were consistent and performed similarly, with both techniques capable of achieving an estimated limit of detection of between 50-100 Rad. Three peaks were identified in the TL glow curve at roughly 110 C, 205 C, and 225 C. The intensity of the 205 C peak was the dominant peak over the time period of this study. The stability of all of the peaks with time since irradiation increased with their corresponding temperature and little or no variation was observed in the glow curve response to a specified total dose attained at different dose rates. The intensity of the 205 C peak decreased logarithmically with time regardless of total dose. Based upon a conservative limit of detection of 330 Rad, a 10,000 Rad dose would still be ...
The goal of the present work has been to clarify the influence of sulphate ions on the oxide films formed on stainless steel and Ni-based alloys in simulated crack chemistry conditions using different ex situ analytical techniques. The main observations of this work can be summarised as follows: The thickness of the films formed in simulated oxygen-free crack chemistry conditions during an exposure of circa 4 days varies roughly in the range 200..500 nm, which corresponds to observations reported in the literature [2]. The presence of 10000 ppb sulphate ions in simulated crack tip conditions seems to lead to a considerably lower thickness of the oxide films when compared to sulphate-free conditions. The presence of 10000 ppb sulphate ions leads also to considerable changes in the morphology of the oxide crystals on the material samples. In the absence of sulphate the outer oxide layer contains elongated round-edged crystals, while in the ...
While tritium exposure to the site-workers in Wolsung NPP is up to about 40% of the total personnel exposure, Ministry of Science and Technology has asked tritium removal facility for requirement of post heavy-water reactor construction. For the purpose of essential removal of tritium from the Wolsung heavy-water reactor system, a preliminary study on the cryogenic Ar-N{sub 2} and H{sub 2}-D{sub 2} distillation process for development of liquid-phase catalytic exchange cryogenic hydrogen distillation process technology. The Ar-N{sub 2} distillation column showed good performance with approximately 97% of final Ar concentration, and a computer simulation code was modified using these data. A simulation code developed for cryogenic hydrogen isotopes (H{sub 2}, HD, D{sub 2}, HT, DT, T{sub 2}) distillation column showed good performance after comparison with the result of a JAERI code, and a H{sub 2}-D{sub 2} distillation column was made. Gas ...
Samples of alloy 800 H (LJNS N08810) and alloy 617 (UNS N06617) were oxidized in a simulated process gas atmosphere. The principal elements of the gaseous environment were 50% H{sub 2}O, 35% H{sub 2} and 5% of CO{sub 2}, CO, and CH{sub 4}, respectively. The experiments were carried out at temperatures from 850 C to 950 C for exposures ranging from 600 to 5,000 hours. After the exposure, the alloy surfaces showed compact oxide layers, which resulted in a depleted zone of oxidizing elements in the substrate layer. Using Electron Probe Microanalysis (EPMA), concentration profiles and the extension of the depleted zone were measured. Calculated theoretical profiles were then fitted to the EPMA-measured profiles, using Fick`s second law of diffusion and resolved by a finite difference method and diffusion coefficients as fitting parameters. The diffusion coefficients for chromium may be represented as D = Do exp.(-Q/RT) with the ...
The aim of this study was to investigate whether sub-ablative pulsed C0{sub 2} laser (1 0,6 {mu}m) irradiation is capable of reducing the susceptibility of the dental enamel to demineralization, and thus achieving a potential caries-protective effect. The crowns of 51 bovine front teeth, embedded in acrylic resin and polished until exposure of flat enamel surface, were used. The samples were cut in cubes of 10x10 mm, and totally coated with acid-resistant nail varnish, except for an enamel exposed window of 16 mm square. Three groups (n=17) were obtained: control group (CG) not irradiated; group laser A (LA) and group laser B (LB) where the samples were irradiated. The conditions were 60 mJ, 100 Hz, 0,3 J/cm{sup 2} for LA and 135 mJ, 10 Hz, 0,7 J/cm{sup 2} for LB. Two samples of each group were submitted to SEM analysis and fifteen to demineralization in 3 ml acetate buffer solution (0,1 mol/L) with pH ...
{sup 14}C is a is a long-lived beta-emitting nuclide (T{sub 1/2} = 5730 years) produced naturally in the upper atmosphere as a result of reactions between neutrons and stable {sup 14}N({sup 14}N(n,p){sup 14}C). Although in a lesser extent, nuclear power plants produce {sup 14}C as well during their routine operation. Since it is converted in {sup 14}CO{sub 2} and mixed throughout the atmosphere, it is incorporated into plant tissues, via photosynthesis process, and hence in food chain. Because of the biological importance of {sup 14}C and long half-life, it is of interest to quantify the amounts released by nuclear industry. The Brazilian nuclear central named Nuclear Central Admiral Alvaro Alberto (CNAAA) has two nuclear reactors of PWR type in operation, Angra I (657 MWe) and Angra II (1350 MWe), and one under construction, Angra III (1309 MWe PWR). The aim of this study was to determine the strength of the sources and the {sup 14}C content in the environment through analyses of air, ...
Meta-analysis to investigate the joint effect of multiple factors in the aetiology of a disease is of increasing importance in epidemiology. This task is often challenging in practice, because studies typically concentrate on studying the effect of only one exposure, sometimes may report the interaction between two exposures, but rarely address more complex interactions that involve more than two exposures. In this paper, we develop a meta-analysis framework that combines estimates from studies of multiple exposures. A key development is an approach to combining results from studies that report information on any subset or combination of the full set of exposures.The model requires assumptions to be made about the prevalence of the specific exposures. We discuss several possible model spec...
We describe the synthesis and characterization of superparamagnetic iron oxide nanoparticle based heavy metal sorbents with various surface chemistries that demonstrate an excellent affinity for the separation of heavy metals in contaminated water systems (i.e. spiked Columbia river water). The magnetic nanoparticle sorbents are prepared from an easy to synthesize iron oxide precursor, followed by a simple, one-step ligand exchange technique to introduce the organic surface functionality of interest chosen to target either specific or broader classes of heavy metals. Functionalized superparamagnetic nanoparticles are excellent sorbent materials for the extraction of heavy metal contaminants from environmental and clinical samples since they are easily removed from the media once bound to the contaminant by simply applying a magnetic field. These engineered magnetic nanoparticle sorbents have an inherently high active surface area (often > 100 m2/g), allowing for ...
Environmental and breathing zone samples were analyzed for formaldehyde at the Pikes Peak Dialysis Center, Colorado Springs, Colorado in August, 1984 and February, 1985. The evaluation was requested by a representative of the Center to determine if there was a health hazard due to formaldehyde. Eight employees were interviewed. The ventilation systems were investigated. Personal protective clothing was inspected. Breathing-zone samples contained 0 28 to 1.0 (mg/m/sup 3/) formaldehyde. The OSHA standard for formaldehyde is 3.7 mg/m/sup 3/. Area formaldehyde concentrations ranged from nondetectable to 0.75 mg/m/sup 3/. Health complaints reported included sore throat, congestion, cough, and eye, nose and throat irritation. Most of the complaints originated from employees in the formalin mixing, reuse sterilization, and dialysis unit packing sections. The exhaust system in the reuse sterilization area was not working efficiently. A variety of ...
This paper summarizes results of preliminary experiments to develop cytological and biochemical indicators for estimating damage to respiratory cells in test animals exposed by inhalation to toxic agents associated with nonnuclear energy production, the specific goal being the application of advanced multiparameter flow-systems technologies to the detection of early atypical cellular changes in lung epithelium. Normal Syrian hamster lung cell samples composed of histiocytes, leukocytes, macrophages, ciliated columnar cells, and epithelial cells were stained with fluorescent dyes specific for different biochemical parameters and were analyzed in liquid suspension as they flowed through a chamber intersecting a laser beam of exciting light. Multiple sensors measured the total or two-color fluorescence and light scatter on a cell-by-cell basis. Cellular parameters proportional to optical measurements (i.e., cell size, DNA content, total protein, nonspecific esterase ...
Natural radioactive materials under certain conditions can reach hazardous radiological levels. The natural radionuclide ("2"3"8U, "2"3"2Th, "4"0K) contents of rock samples at various locations in the North Tushki area were investigated using gamma-spectrometric analysis. Estimates of the measured radionuclide content have been made for the absorbed dose rate of gamma radiation. The equivalent radium (R_e_q) and the external hazard index (H_e_x) which resulted from the natural radionuclides in soil are also calculated and tabulated. The studied samples have been collected from various rock exposures in the North Tushki area. The distribution of major oxides, U and Th were studied. It is found that the enrichment and depletion of the major oxides are mainly due to the effect of hydrothermal alteration, which caused mobility of some major oxides, which increases some elements and decreases others. It is important to mention ...
Intact rat fat cell exposed to 12.5 ..mu..M (..gamma..-32P)ATP incorporate label into specific proteins within minutes. By solubilizing the reaction mixture with SDS which bypasses the subcellular fractionation steps, the labeled proteins can be identified in autoradiographs of SDS-PAGE gels. The most prominently labeled protein has an M/sub r/ of 42,000. Localization of this component to the cell surface can be made on the basis of inhibition of phosphorylation by addition of a protein derived from the rat brain with protein kinase inhibitory property, susceptibility of the phosphorylated protein to the tryptic digestion, inhibition of phosphorylation of this protein after brief exposure to melittin. To rule out the possibility that the cell surface protein might be a mitochondrial contaminant from broken cells, /sup 32/Pi-labeled and (..gamma..-/sup 32/P)ATP-labeled cells were chromatographed on a rabbit anti-pyruvate dehydrogenase antibody-Sepharose 4B column. A ...
A representative National Survey to evaluate the exposure to natural sources of ionizing radiation in dwellings was conducted in all the 21 Italian Regions from 1989 to 1998, and the complete results are reported in this paper. Radon concentration was measured for two consecutive 6-month periods (generally covering the spring-summer and autumn-winter seasons) in one room, usually the main bedroom, of each surveyed dwelling. Validated radon concentration measurements were obtained for a total of 5631 dwellings, distributed in 232 towns (all the 50 towns with more than 100,000 inhabitants and 182 randomly sampled smaller towns). The national average, weighted by the population of each Region, of the annual radon concentration is 70Bqm{sup -3}, the geometric mean is 52Bqm{sup -3}, and the geometric standard deviation is 2.1. The fraction of dwellings with a radon concentration exceeding the reference levels of 150, 200, 400, and 600Bqm{sup -3} are ...
Comparisons of the 60 Hz electric field exposures associated with high voltage transmission lines to those associated with common household sources can provide an important input to regulatory decisions that involve transmission line fields. Electric blankets are of interest in this context because the exposures they produce are among the most intense and prolonged of any of the household sources of 60 Hz electric field exposure. This paper presents a theoretical analysis of the body surface fields induced by electric blankets. Electric blanket exposure intensities are compared to those associated with transmission lines.
The motivation of this work is to develop high reflectance normal-incidence multilayer mirrors in the 8-12 nm wavelength region for applications in astronomy and extreme ultraviolet lithography. To achieve this goal, Mo/Sr and Mo/Y multilayers were studied. These multilayers were deposited with a UHV magnetron sputtering system and their reflectances were measured with synchrotron radiation. High normal-incidence reflectances of 23% at 8.8 nm, 40.8% at 9.4 nm, and 48.3% at 10.5 nm were achieved. However, the reflectance of Mo/Sr multilayers decreased rapidly after exposure to air. Attempts to use thin layers of carbon to passivate the surface of Mo/Sr multilayers were unsuccessful. Experimental results on the refractive index {tilde n} = 1-{delta} + i{beta} of yttrium and molybdenum in the 50-1300 eV energy region are reported in this work. This is the first time ever that values on the refractive index of yttrium are measured in this energy range. The absorption ...
Sixty-Hz magnetic field exposures were measured for 45 adult residents of Maine. Thirty of the subjects resided near rights-of-way (ROWs) with either 345- and 115-kV transmission lines, or ROWs with only 115-kV transmission lines; fifteen resided far from any transmission lines. Personal exposure data for a single 24-hour period was acquired with the EMDEX. The EMDEX's event-marker button was used to partition exposures into Home and Away components. Also, three area measurements were taken for each subject during the personal exposure measurement period: (1) 24-hr fixed-site bedroom measurement with a second EMDEX; (2) Spot measurements in at least three rooms of every residence; and (3) Spot measurements outside each residence. Residence near transmission lines highly loaded during the measurement period was associated with increased Home and Total exposure relative to a ...
We investigated the association between biomarkers of dermal exposure, naphthyl-keratin adducts (NKA), and urine naphthalene biomarker levels in 105 workers routinely exposed to jet-fuel. A moderate correlation was observed between NKA and urine naphthalene levels (p?=?0.061). The NKA, post-exposure breath naphthalene, and male gender were associated with an increase, while CYP2E1*6 DD and GSTT1-plus (++/+-) genotypes were associated with a decrease in urine naphthalene level (p?0.0001). The NKA show great promise as biomarkers for dermal exposure to naphthalene. Further studies are warranted to characterize the relationship between NKA, other exposure biomarkers, and/or biomarkers of biological effects due to naphthalene and/or PAH exposure. PMID:21961652
The GSD must be considered as a quantity by means of which the risk in a given population can be described exclusively in terms of genetic risk. In cases of a simultaneous increase in the rate of examinations, the GSD may lead to a misinterpretation of the population exposure, suggesting a decreasing trend, although there is an actual increase in the somatic radiation exposure. It is recommended to indicate not only the GSD but also the amount of somatic radiation exposure of the population for each specific source when comparing and evaluating radiation exposures from different sources. Although the somatically significant dose formally would be suited as a complement to the GSD, it is recommended to use the effective per caput dose equivalent. It must be pointed out that the application of the concept of effective dose equivalent is only appropriate for comparative evaluations of the population ...
Human exposure to environmental chemicals is most correctly characterized as exposure to mixtures of these agents. The metals/metalloids, lead (Pb), cadmium (Cd), and arsenic (As), are among the leading toxic agents detected in the environment. Exposure to these elements, particularly at chronic low dose levels, is still a major public health concern. Concurrent exposure to Pb, Cd, or As may produce additive or synergistic interactions or even new effects that are not seen in single component exposures. Evaluating these interactions on a mechanistic basis is essential for risk assessment and management of metal/metalloid mixtures. This paper will review a number of individual studies that addressed interactions of these metals/metalloids in both experimental and human exposure studies with...
In evaluating the risk associated with low levels of exposure to toxicants, it is clear that DNA repair, one of the main defenses against agent damage, is not a constant. It can be modified by age, time of day, and physiological state. Nutrition, especially caloric restriction (CR), can modify almost every step in the process of protecting genomic integrity. And history of exposure can modify DNA repair. Thus, the conditions of exposure are almost as important to toxicity as the exposure itself, even at the level of DNA repair. Extrapolation from high to low dose, to be consistent with what is known, should be less a mathematical exercise than an exercise in toxicological judgement, which puts the exposure in proper perspective. This appears to be true at almost every level in the process including a response with a toxic stimulus, even those thought to be very basic, such as DNA ...
The U.S. Department of Energy Order 435.1, Radioactive Waste Management, requires a disposal authorization statement authorizing operation (or continued operation) for low-level waste disposal facilities. In fulfillment of these requirements, a disposal authorization statement was issued on October 25, 1999, authorizing the Hanford Site to transfer, receive, possess, and dispose of low-level radioactive waste at the 200 East Area burial grounds and the 200 West Area burial grounds. One of the conditions is that monitoring plans for the 200 East Area and 200 West Area low-level burial grounds be written and approved by the Richland Operations Office. As a result of a record of decision for the Hanford Site Solid Waste Program and acceptance of the Hanford Site Solid Waste Environmental Impact Statement, the use of the low-level burial ground (LLBG) as a disposal facility for low-level and mixed low-level wastes has been restricted to lined trenches and the Navy reactor-compartment ...
A stiff skin forms on surface areas of a flat polydimethylsiloxane (PDMS) upon exposure to focused ion beam (FIB) leading to ordered surface wrinkles. By controlling the FIB fluence and area of exposure...Full Text Available
Sunlight exposure has been suggested as a cause of AMD. To examine this, we collected detailed histories of ocular sun exposure in 838 watermen who work on the Chesapeake Bay. The presence and severity...Full Text Available
Assessments of drinking water safety rely on the assumption that ingestion represents the principal route of exposure. A review of the experimental literature revealed that skin penetration rates for...Full Text Available
Domestic, low-level exposure to radon gas is considered a major environmental lung-cancer hazard involving DNA damage to bronchial cells by α particles from radon progeny. At domestic exposure...Full Text Available
The use of an extraction of the heme pigments hemoglobin and myoglobin as a test for the heat exposure of back bacon was investigated by treating back bacon at varying temperatures of 50-70 degrees...Full Text Available
Oxidative stress contributes to the pathophysiology of exposure to heavy metals/metalloid. Beneficial renal effects of some medications, such as chelation therapy depend at least partially on the ability...Full Text Available
BackgroundSome epidemiologic studies have suggested an association between electromagnetic field exposure induced by high voltage power lines and childhood leukemia, but null results...Full Text Available
Neurological disorders induced by long-term exposure to organic solvents typically have a slowly progressive clinical course, which may be arrested or even reversed following discontinuation of exposure....Full Text Available
The onset of parental behavior has profound and enduring effects on behavior and neurobiology across a variety of species. In some cases, mere exposure to a foster neonate (and a subsequent...Full Text Available
Locomotive drivers in the steam engine era were exposed to asbestos during their vocational training for two years while training in workshops. Later in their career they had exposure to coal and diesel...Full Text Available
BackgroundIn rats, alcohol exposure during the period of rapid brain growth produces long-term changes in the free-running period, photoentrainment and phase-shifting...Full Text Available
A historical prospective mortality study was conducted on a cohort of 34 156 male members of a heavy construction equipment operators union with potential exposure to diesel exhaust emissions. This...Full Text Available
BackgroundA key question in the risk assessment of exposures to multiple chemicals is whether mixture effects may occur when chemicals are combined at low doses which individually...Full Text Available
BackgroundIn retrospective studies of the health effects of home and garden pesticides, self-reported information typically forms the basis for exposure assessment. Study participants...Full Text Available
The United Kingdom Atomic Energy Authority mortality study was designed to investigate the relation between exposure to ionising radiation and mortality among the authority's employees. The present...Full Text Available
Aims: To investigate the exposure to dinitrotoluene (DNT) and trinitrotoluene (TNT) and the resulting effects in workers which occur during the disposal of military waste. Methods:...Full Text Available
Workers from cotton mills were exposed to cotton dust during carding in an experimental cardroom. Cotton from different geographical locations with varying amounts of endotoxin were used. Exposure levels...Full Text Available
BackgroundThere has been increasing interest in the ability of the internet to produce behaviour change. The focus of this study was to describe program exposure across three intervention...Full Text Available
Alternatives for developing chronic exposure limits for noncancer effects of trichloroethylene (TCE) were evaluated. These alternatives were organized within a framework for dose-response assessment--exposure:dosimetry...Full Text Available
OBJECTIVES: To appraise epidemiological evidence of the purported association between residential exposure to power frequency magnetic fields and adult cancers. METHODS: Literature review and epidemiological...Full Text Available
Epidemiologic research concerning electric and magnetic fields in relation to cancer has focused on the potential etiologic roles of residential exposure on childhood cancer and occupational exposure...Full Text Available
Exposure to dieldrin induces neurotoxic effects in the vertebrate CNS and disrupts reproductive processes in teleost fish. Reproductive impairment observed in fish by dieldrin is likely the...Full Text Available
Neonatal exposure to diethylstilbestrol (DES) can alter the structure of the testicular excurrent ducts in rats. We characterized these changes according to dose and time posttreatment and established...Full Text Available
In rats, damage to neuronal populations in some brain regions occurs in response to neonatal alcohol exposure coinciding with the period of rapid brain growth. These alcohol-induced defects...Full Text Available
In order to decrease tritium exposure to workers, the ratio of which is up to 40% of total exposure, tritium removal facility is getting to be one of the considerable parameters in Korea, due to the next CANDUs to be operated at Wolsung NPP. For investiga...
While tritium exposure to the site-workers in Wolsung NPP is up to about 40% of the total personnel exposure, Ministry of Science and Technology has asked tritium removal facility for requirement of post heavy-water reactor construction. For the purpose o...
ObjectivesTo study inhalation and dermal exposure to hexamethylene diisocyanate (HDI) and its oligomers as well as personal protection equipment (PPE) use during task performance...Full Text Available
Sentinel species such as bottlenose dolphins (Tursiops truncatus) can be impacted by large-scale mortality events due to exposure to marine algal toxins. In the Sarasota Bay region...Full Text Available
A retrospective case-control study tested the hypothesis that exposure to hydrocarbon combustion products is associated with the development of renal cell carcinoma. One control per case, matched for...Full Text Available
Chronic arsenic exposure has been suggested to contribute to diabetes development. We performed a systematic review of the experimental and epidemiologic evidence on the association of arsenic and type...Full Text Available
The antibiotic resistance patterns of gram-negative fecal bacteria from pigs in three herds with different histories of antibiotic exposure were examined. In general, smaller proportions of antibiotic-resistant...Full Text Available
BackgroundBreast-feeding may affect the risk of developing allergy during childhood and may also cause exposure to immunotoxicants, such as polychlorinated biphenyls (PCBs), which...Full Text Available
Sodium-dependent high-affinity choline uptake was measured in the striatum, frontal cortex, hippocampus, and hypothalamus of rats after acute exposure (45 min) to pulsed (2 microseconds, 500 pps) or continuous-wave 2,450-MHz microwaves in cylindrical waveguides or miniature anechoic chambers. In all exposure conditions, the average whole-body specific absorption rate was at 0.6 W/kg. Decrease in choline uptake was observed in the frontal cortex after microwave exposure in all of the above irradiation conditions. Regardless of the exposure system used, hippocampal choline uptake was decreased after exposure to pulsed but not continuous-wave microwaves. Striatal choline uptake was decreased after exposure to either pulsed or continuous-wave microwaves in the miniature anechoic chamber. No significant change in hypothalamic choline uptake was observed under any of ...
OBJECTIVES--This case cohort study examines whether there is an association between exposure to electric and magnetic fields and suicide in a population of 21,744 male electrical utility workers from...Full Text Available
Methylphenidate (MPH) is commonly prescribed in childhood and adolescence for the treatment of attention–deficit/hyperactivity disorders. In rodents, MPH exposure during preadolescence...Full Text Available
The document published under A/63:46 and titled report of the scientific committee of United Nations for the study of ionizing radiations effects, gives the situation of the fifty sixth session of the committee that stood at Vienna from the 10. to 18. july 2008. In the chapter 3 of this report the writers summarize the strategic planning and the working program of the scientific committee for the period 2009-2013. They note that the committee worry about the inadequate means, particularly in personnel. The priorities for the given period will be the medical exposure of patients, the radiation levels and the effects of energy production, the exposure to natural radiation sources and the improvement of the understanding of the effects of the low doses radiation exposure. (N.C.)
The exposure of heat-resistant alloys to high temperature can significantly change their mechanical properties. This paper presents and analyzes data on the effect of thermal exposure on the tensile and impact behavior of three cast materials -- the HK-40, HP-50, and 21Cr-32Ni-Fe alloys -- and of wrought material -- Alloy 800. The changes in tensile and impact properties caused by high-temperature exposure are reviewed. Reasons for these property changes and needs for considering them in the design, operation, and life assessment of high-temperature equipment are discussed.
The assumed linear relationship between exposure to radiation and cancer incidence is questioned in this article. The current research data on radiation effects at the cellular level is reviewed, as are epidemiological studies of background radiation effects and health effects of populations exposed to low levels of radiation exposure via employment or medical treatments. Statistics reveal that threshold levels currently in force need to be reviewed. Some evidence of beneficial effects of low level radiation exposure effects of low level radiation exposure is also presented, and so regulations should be reviewed at an international level. (UK).
Objective: To estimate exposure dose of personnel around patients by Monte Carlo method and integration method. Methods: Exposures were estimated by a Monte Carlo practical program with Visual Basic 6.0 and integration method using 'pen-and-paper'. Results: Exposures for rectangle and ellipse sources were calculated. The difference between different methods for various sources were 0.88% and 0.61%, respectively. Conclusion: The results estimated by Monte Carlo method are close to those of integration method. It is illustrated that doses of other people estimated by Monte Carlo method are significant
Studies were initiated to examine in rats the effects of a protracted exposure to inhaled "2"3"9PuO_2. Graphs are presented to show effect of multiple exposures to "2"3"9PuO_2 on the deposition and clearance of "2"3"9Pu in the alveoli.
An indoor survey in order to estimate the population exposure in five towns of an Italian Region is presented. A particular methodology for the campaign was planned and is being applied. Gamma spectrometry of building materials, exposure rate measurements indoors and outdoors and radon concentration measurements indoors were taken with different techniques. A correlation was found between mean gamma exposure rate and mean radon concentration in the houses investigated. An evaluation of mean effective dose equivalents for the inhabitants of the five towns is reported.
The radiation burden of the people of the GDR in relation to biomedical radiography altogether as well as organ doses, gonad doses and genetically significant doses in detail are outlined. The concepts of radiation protection and standards of radiographic examination are demonstrated. Possibilities of influencing radiation exposure by scientifically based indication of X-ray examination, application of new and improvement of usual examination techniques are discussed with regard to quality assurance and control. Proposals concerning the reduction of radiation exposure of the GDR population are presented.
For comparison of radiation exposure and risk in different diagnostic procedures for adults and children dose measurements and calculations of organs with special risk were carried out. Parameters of image formation influencing image quality as well as of exposure concerning infants and children are recorded and discussed as to radiation exposure and protection. Conclusions are drawn with respect to systems of image formation and to standards of examination and quality assurance.
Despite successful reduction of the general lead exposure, this heavy metal is still a matter of public concern due to the fact that associations with intellectual impairment or delayed puberty are found to correlate with very low lead blood concentrations. Lead in tap water is still an important contribution to lead exposure which may cause health risk for infants. Therefore, lead pipes should be completely sanitated by exchange against pipes made from more healthy materials. (orig.)
Daily exposures of adult beagle dogs to inhaled radon daughters and to uranium ore dust for 4-1/2 to 6 yr have produced respiratory tract carcinomas, at similar cumulative working level months (WLM) of exposures to those which induced carcinomas in uranium miners. Biological data from the beagle-dog experiments can therefore be used for prediction of carcinogenic risk under changing exposure conditions in future uranium miners.
Repeated exposure to cold air reduces the metabolic response to cold air exposure in man. The purpose of this investigation was to measure the change in resting metabolic rate (RMR) with exposure to 22C air and 4C air during a 12 day period. Four women sat in 22C air for 45 min followed by 45 min in 4C air each day for ten days. The authors measured RMR during a 45 min period in 22C air followed by 45 min in 4C air on four days. All subjects began their morning exposures on a Monday within 2 days of the onset of menses completing the study on a Friday, 12 days later. Subjects dressed in a T-shirt, shorts and cotton socks. During 45 min of exposure to warm air, RMR remained steady at 10% of VO{sub 2peak} on Day 1 and 10% on Day 5. RMR during exposure to warm air significantly increased to 13% of VO{sub 2peak} on Day 8 and remained elevated at 13% on Day 12. ...
Acquisition of three-alternative simultaneous matching-to-sample and oddity-from-sample was investigated. Five goldfish were trained on matching and five on oddity for a minimum of 70 days. Subsequently,...Full Text Available
Boat sampling technique (BST) is a surface sampling technique, which has been developed for obtaining, in-situ, metal samples from the surface of an operating component without affecting its operating service life. The BST is non-destructive in nature and the sample is obtained without plastic deformation or without thermal degradation of the parent material. The shape and size of the sample depends upon the shape of the cutter and the surface geometry of the parent material. Miniature test specimens are generated from the sample and the specimens are subjected to various tests, viz. Metallurgical Evaluation, Metallographic Evaluation, Micro-hardness Evaluation, sensitisation test, small punch test etc. to confirm the integrity and assessment of safe operating life of the component. This paper highlights design objective of boat sampling ...
Austenitic stainless steels (304-type) have been implanted with nitrogen ions in order to investigate the effects of implanted nitrogen on their electrochemical behaviour and on the nature of the passive film formed on the steels in acid (0.5M H{sub 2}SO{sub 4}). Alloys with two nitrogen doses have been prepared (2.5x10{sup 16} and 2x10{sup 17} N atoms/cm{sup 2}). The implanted alloys have been characterized by {sup 15}N-NRA (nuclear reaction analysis) and XPS (X-ray photoelectron spectroscopy). Alloy surfaces with well-defined N concentrations were prepared, prior to the electrochemical measurements, by argon-ion sputtering of the implanted material for a fixed time in order to reach a well-defined point on the nitrogen depth profile. The samples were then transferred without exposure to air to an electrochemical cell mounted in an inert gas glove box. The implanted nitrogen modifies the electrochemical behaviour of the alloy. The anodic ...
Austenitic stainless steels (304-type) have been implanted with nitrogen ions in order to investigate the effects of implanted nitrogen on their electrochemical behaviour and on the nature of the passive film formed on the steels in acid (0.5M H_2SO_4). Alloys with two nitrogen doses have been prepared (2.5x10"1"6 and 2x10"1"7 N atoms/cm"2). The implanted alloys have been characterized by "1"5N-NRA (nuclear reaction analysis) and XPS (X-ray photoelectron spectroscopy). Alloy surfaces with well-defined N concentrations were prepared, prior to the electrochemical measurements, by argon-ion sputtering of the implanted material for a fixed time in order to reach a well-defined point on the nitrogen depth profile. The samples were then transferred without exposure to air to an electrochemical cell mounted in an inert gas glove box. The implanted nitrogen modifies the electrochemical behaviour of the alloy. The anodic dissolution in the active state ...
B vitamins and polymorphisms in genes coding for enzymes involved in one-carbon metabolism may affect DNA synthesis and methylation and thereby be implicated in carcinogenesis. Previous data on vitamins B2 and B6 and genetic polymorphisms other than those involving MTHFR as risk factors for gastric cancer (GC) are sparse and inconsistent. In this case-control study nested within the European Prospective Investigation into Cancer and Nutrition cohort, cases (n = 235) and controls (n = 601) were matched for study center, age, sex, and time of blood sampling. B2 and B6 species were measured in plasma, and the sum of riboflavin and flavin mononucleotide was used as the main exposure variable for vitamin B2 status, whereas the sum of pyridoxal 5'-phosphate, pyridoxal, and 4-pyridoxic acid was used to define vitamin B6 status. In addition, we determined eight polymorphisms related to one-carbon metabolism. Relative risks for GC risk were calculated ...
Tree swallows were used to evaluate movement and potential impacts of contaminants from sediments in Newton Creek (diesel range organics: DROs) and Sheboygan River (PCBs), tributaries to Lake Superior and Lake Michigan, respectively. Contaminated sites occurred along the course of each river, while reference sites were located upstream or on a nearby river. Productivity was monitored and eggs, day 1 nestlings, and day 12 nestlings were collected from each nest. Whole body or egg homogenates were analyzed for PCBs or DROs. EROD activity in livers from day 12 nestlings is being determined for both PCB and DRO exposures. In the Newton Creek study, hatching success was similar for DRO and reference sites. DROs were detected in gastrointestinal tracts of 1 nestling from the reference and 1 from the contaminated site. DROs were not detected in any egg samples. In the Sheboygan River study, hatching success rates differed between 1 reference and 1 ...
Although some polymer conductors of electricity (ex. Polyanilines) are materials known for more than 100 years, only recently have the interesting chemical, electrical and optic properties of their insulating and conducting forms been recognized. Advances made in the chemistry of polymer conductors have also led to improvements in processing them. This work studies a practical application of these materials: the use of polymer conductors for the remote welding of insulating thermoplastic polymers, using energy from microwaves for the local heating of the union. Many thermoplastics (for ex. Polyethylene) do not absorb, or absorb very little, energy from microwaves. Different conductor materials (conductor polymers, carbon nanotubes), however, heavily absorb energy from microwaves with the resulting heating. In this way the welding zone can be heated without affecting the rest of the piece. Conductor polymers (polyanilines) were synthesized chemically and they were characterized by ...
A number of procedures in diagnostic radiology and cardiology make use of long exposures to x-rays from fluoroscopy units. Although numerous studies have been performed to measure or calculate skin dose from these procedures, there have only been a handful of studies to determine the dose to the other organs. This thesis was focused on devising a method to calculate the absorbed dose to underlying tissues and organs. The work was performed in several stages. First, a commercial convolution/superposition-based treatment planning system used in radiation oncology was modified and complemented to make it usable with the low energies of x-rays used in diagnostic radiology. This required generation of energy deposition kernels in the kilovoltage energy range. The kernels were generated using the EGS4 Monte Carlo system of codes and added to the treatment planning system. The treatment planning system was then evaluated for its accuracy of calculations at low energies ...
Vulnerability of 25-hydroxy-(26,27-{sup 3}H)vitamin D{sub 3} 3{beta}-N-(4-azido-2-nitrophenyl)glycinate, a photoaffinity analogue of 25-hydroxyvitamin D{sub 3} (25-OH-D{sub 3}) toward standard conditions of carboxymethylationin promoted the authors to synthesize 25-hydroxyvitamin D{sub 3} 3{beta}-3{prime}-(N-(4-azido-2-nitrophenyl)amino)propyl ether (25-ANE), a hydrolytically stable photoaffinity analogue of 25-OH-D{sub 3}, and 25-hydroxyvitamin D{sub 3} 3{beta}-3{prime}-(N-(4-azido-2-nitro-(3,5-{sup 3}H)phenyl)amino)propyl ether ({sup 3}H-25-ANE), the radiolabeled counterpart of 25-ANE competes for the 25-OH-D{sub 3} binding site in rat serum vitamin D binding protein (rDBP). On the other hand, UV exposure of a sample of purified rat DBP (rDBP), preincubated in the dark with {sup 3}H-25-ANE, covalently labeled the protein. However, very little covalent labeling was observed in the absence of UV light or in the presence of a large excess of ...
Gas-insulated systems employing SF/sub 6/ are utilized in a variety of applications in power delivery systems. Because electric arcs, sparks or corona can decompose SF/sub 6/ into byproducts having chemical properties different from SF/sub 6/, environmental concerns arise regarding inadvertent human exposures to electrically-decomposed SF/sub 6/. Biological assays in our laboratory using mammalian cell culture systems have revealed that spark-decomposed SF/sub 6/ produces cell death, and the extent of cell killing increases with increasing spark energy. Chemical analysis of spark-decomposed SF/sub 6/ has identified the major decomposition pathways and byproducts, but biological testing of individual or byproduct mixtures has indicated that these major decomposition products do not contribute, in a significant fashion, to the cell lethality seen in our assays. Further experiments have suggested that S/sub 2/F/sub 10/ may be produced under our decomposition ...
The Salt Decontamination Demonstration confirmed that the precipitation process could be used for large-scale decontamination of radioactive waste sale solution. Although a number of refinements are necessary to safely process the long-term requirement of 5 million gallons of waste salt solution per year, there were no observations to suggest that any fundamentals of the process require re-evaluation. Major accomplishments were: (1) 518,000 gallons of decontaminated filtrate were produced from 427,000 gallons of waste salt solution from tank 24H. The demonstration goal was to produce a minimum of 200,000 gallons of decontaminated salt solution; (2) cesium activity in the filtrate was reduced by a factor of 43,000 below the cesium activity in the tank 24 solution. This decontamination factor (DF) exceeded the demonstration goal of a DF greater than 10,000; (3) average strontium-90 activity in the filtrate was reduced by a factor of 26 to less than 10"3 d/m/ml versus a goal of less than ...
Nuclear fuel vendors in Japan are now studying reprocessed uranium (RepU) fuel in order to prepare for full scale utilization in the future. Separate studies are made for PWR and BWR fuel. The study consists of 2 phrases. The purposes of phase-1 are to understand various RepU characteristics in the fuel fabrication process, to analyze the core characteristics by loading RepU assemblies, to solve the problems clarified in the study, and to collect basic data for licensing. In phase-2, the effects of impurities on the fabrication process will be evaluated, and the safety of RepU fuel manufacturing will be confirmed with a RepU fuel fabrication campaign in 1990. The neutronic data will be collected after insertion into power reactors, and the data will be used to verify plant safety for full utilization of RepU in the future. This paper summarizes the phase-1 study results. 1. RepU Characteristics. The internal and external radiation exposures due to nuclide ...
The mechanisms of brown adipocyte proliferation and differentiation during cold acclimation (and/or adaptation to hyperphagia) have been studied by quantitative photonic radioautography. (/sup 3/H)thymidine was injected to warm-acclimated (25/sup 0/C) rats and to animals exposed to 5/sup 0/C for 2 days. Samples of interscapular brown adipose tissue were collected for quantitative analysis of mitotic frequencies at various periods of time (4 h-15 days) after the injection of (/sup 3/H)thymidine, the rats being maintained at the temperatures to which they were initially exposed. It was found that cold exposure for 2 days markedly enhanced mitotic activity in endothelial cells, interstitial cells, and brown preadipocytes rather than in fully differentiated brown adipocytes. The total tissue labeling index (percent of labeled nuclei) increased approx.70 times over control values. The authors now report that cellular labeling progressively increased ...
The proposed aim of the work is to verify the effects produced on different kinds of environmental pollutants after exposure to a low frequency radiation such as microwaves. They have proved capable of producing minimum heating of the matrix as well as modifications in the structure of the molecules at the level of simple bonds. Steps were also taken ti check whether the degradation action of the microwaves could be boosted by sunlight. For this reason tests were run also on samples irradiated using microwaves and a lamp capable of simulating the sun's spectrum, as well as in the presence of a single lamp. [Italian] Lo scopo di questa ricerca e' di verificare gli effetti prodotti su inquinanti ambientali, di diversa natura, a seguito di un'esposizione ad una radiazione a bassa frequenza come le microonde. Le microonde possono produrre minimi riscladamenti della matrice e modificazioni della struttura delle molecole, a ...
The operation of nuclear processing facilities and defense-related nuclear activities has resulted in contamination of near-surface and deep-subsurface sediments with both radionuclides and metals. The presence of mixed inorganic contaminants may result in undetectable microbial populations or microbial populations that are different from those present in uncontaminated sediments. To determine the impact of mixed radionuclide and metal contaminants on sediment microbial communities, we sampled a processing pond that was used from 1948 to 1975 for the disposal of radioactive and metal-contaminated wastewaters from laboratories and nuclear fuel fabrication facilities on the Hanford Site in Washington State. Because the Hanford Site is located in a semiarid environment with average rainfall of 159 mm/year, the pond dried and a settling basin remained after wastewater input into the pond ceased in 1975. This processing pond basin offered a unique opportunity to obtain ...
According to ICRP 60 and European-Directive 96/29, Naturally Occurring Radioactive Materials (NORM) and Technical Enriched Naturally Occurring Radioactive Materials (TENORM) have to take the radiation protection of the general population as well as of workers into account. The German radiation protection regulations stress that particularly. In connection with these regulations, various measurement programs have been and still are performed to investigate the relevant exposure paths. One of these programs is the determination of the intake of natural occurring radionuclides of the uranium decay series in individuals of the public, in exposed regions and houses and also at NORM workplaces by excretion analysis. Excretion analysis surveillance is one of the common tools for internal dosimetry. Sources of primordial radionuclides could be the ingestion of foodstuff and water and the incorporation of (mostly airborne) pollution on work places. The main focus in this ...
We report on the transport properties of a high mobility two-dimensional hole system (2DHS) confined in GaAs/AlGaAs quantum wells grown by molecular-beam epitaxy on the (100) surface of GaAs. The quantum wells are modulation doped with carbon utilizing a resistive filament source. At T=0.3 K and carrier density p=1x10"1"1 cm"-"2, a mobility of 10"6 cm"2/Vs is achieved. At fixed carrier density p=10"1"1 cm"-"2, the mobility is found to be a nonmonotonic function of the quantum well width. The mobility peaks at 10"6 cm"2/Vs for a 15-nm well and is reduced for both smaller and larger well widths for these (100) samples. The mobility anisotropy is found to be small. Mobility along [011] is approximately 20% higher than along the [011] direction. In addition, the low-temperature carrier density is found to have low sensitivity to light. The hole density increases by only #approx#10% after exposure to red light at T=4.2 K. In structures designed for ...
Studies by the University of Lowell Radiation Laboratory and the US National Marine Fisheries Service N.E. Laboratory in Gloucester, MA on softshelled clams (Mya arenaria) demonstrated the effectiveness of low to medium doses of Cobalt 60 source gamma irradiation in the inactivation of Escherichia coli, Salmonella typhimurium, Staphylococcus aureus and Streptococcus faecalis. Post-irradiation survival and organoleptic studies when extended to hardshelled clams (Mercinaria mercenaria) and American oysters (Crassostrea virginica) showed no significant decline in consumer qualities or 6 day post irradiation survival in oysters at doses of up to 3.0 kGy. The capacities of the American oyster to sustain relatively high doses of gamma irradiation were demonstrated by 6 day post-exposure survivorship values of greater than 90% for samples receiving 3.0, 5.0 and 7.0 kGy. Initial studies of inactivation of Polio I virus and a simian rotavirus (SA-11) ...
The physics and technology of this new Cerenkov detector are discussed, including materials studies, construction techniques, and resolution measurements. Sources of resolution error are individually identified and measured where possible. The results of all studied indicate that the measurement resolution is understood. This work has led to the adoption of a large scale ring imaging detector as part of a new high energy physics spectrometer, the SLD, at the Stanford Linear Accelerator Center. Results from an amplitude analysis of strange meson final states in K/sup /minus//p ..-->.. /ovr K/sub 0//..pi../sup /minus//p interactions are presented. The data derive from a 4 event/nb exposure of the LASS (large Aperture Superconducting Solenoid) spectrometer to an 11 GeV/c K/sup /minus// beam. The data sample consists of /approximately/100,000 vents distributed over the Dalitz plot of the channel. The process is observed to be dominated by the ...
The Toxicological Evaluation of Realistic Emissions of Source Aerosols (TERESA) study involved withdrawal, aging, and atmospheric transformation of emissions of three coal-fired power plants. Toxicological evaluations were carried out in rats exposed to different emission scenarios with extensive exposure characterization. Data generated had multiple levels of resolution: exposure, scenario, and constituent chemical composition. Here, we outline a multilayered approach to analyze the associations between exposure and health effects beginning with standard ANOVA models that treat exposure as a categorical variable. The model assessed differences in exposure effects across scenarios (by plant). To assess unadjusted associations between pollutant concentrations and health, univariate analyses...
Atrazine is one of the most commonly used herbicides in the United States. While effective on target plants, it has been associated with harmful health effects in non-target organisms such as fish, amphibians and mammals. In this study, growth effects on human liver cells were determined after exposure to increasing concentrations of this herbicide. Growth of immortalized human hepatoma HepG2 cells was inhibited by atrazine concentrations of 625 ppb after 72 h exposure and flow cytometry analysis demonstrated HepG2 cells exposed to 100 ppb atrazine accumulated in S phase after 48 h compared to untreated cells. Expression of cell cycle specific cyclin proteins was altered after atrazine exposure with cyclin E levels significantly decreased after a 24 h exposure and cyclin B levels decreased...
Efforts to assess and quantify deleterious effects from toxicants concentrate mainly on single agents whereas real world environmental and occupational exposures to natural and anthropogenic agents entail quite often the concomitant presence of several toxicants. For occupational important exposure situations, combined exposures to physical and chemical agents such as radon and smoking or asbestos and smoking, respectively, were shown to produce over-additive effects at exposure levels typical for earlier workplaces. Already the elucidation of possible health risks from a single agents, its dependence on exposure level, exposure rates, age at exposure and its expression in time is a complex endeavour. Therefore in the past and the present the main emphasis in radiation protection, toxicology, and public health is on the study and assessment ...
Previous research has shown that SAR hotspots are induced within the laboratory rat and that the resulting thermal hotspots are not entirely dissipated by bloodflow. Two experiments were conducted to determine if hotspot formation in the body and tail of the rat, which is radiation frequency specific, would have behavioral consequences. In the first experiment rats were placed in a plexiglas cage one side of which, when occupied by the rat, commenced microwave radiation exposure; occupancy of the other side terminated exposure. Groups of rats were tested during a baseline period to determine the naturally preferred side of the cage. Subsequent exposure to 360-MHz, 700-MHz or 2450-MHz microwave radiation was made contingent on preferred-side occupancy. A significant reduction in occupancy of the preferred side of the cage, and hence, microwaves subsequently occurred. Reduced exposure to 360-MHz and ...
The corrosion resistance of steel-reinforced mortar specimens made from alinite cement was investigated using ordinary Portland cement (OPC) specimens as reference. The specimens were prepared and exposed in three different environments: continuous exposure in tap water, interrupted exposure in tap water, and interrupted exposure in 3.5% NaCl solution. The steel weight loss and the half cell potential were measured vs. exposure time, up to the age of 12 months. Pore solution extraction and analysis and porosity determination were also performed. In continuous exposure in tap water, alinite cement provided adequate protection against corrosion. In interrupted exposure in tap water, a higher corrosion was observed for alinite cement compared to OPC. In the case of interrupted exposure in 3.5% NaCl solution, the simultaneous action of free ...
Safety standards for exposure to radiofrequency radiation must be based upon biologic consequences of exposure to such environments. Behavioral-based measures are considered to be the most-sensitive indices of biological effects. Current safety guidelines are based upon average power density and may not be relevant to the high-peak-power, short pulse width microwave radiation produced by newly developed high peak power microwave sources. The effects of exposure to high-peak-power radiation on reflexive responding and motor function in Fischer 344/N rats were assessed by measuring startle and general activity, and disruption of on-going performance of a rotarod task, respectively. The emitter used was the TEMPO repeat pulse axially extracted vircator. Exposure to single pulses resulted in significant startle responses. Exposure to 1 pps for 10 s produced significant alterations in ...
The development of attenuated response ({open_quotes}tolerance{close_quotes}) to daily ozone (O{sub 3}) exposures in the laboratory is well established in healthy adult volunteers. However, the capability of asthmatics to develop tolerance during multiday ozone exposures in unclear. We exposed 10 adult volunteers with mild asthma to 0.4 ppm O{sub 3} in filtered air for 3 h/d on 5 consecutive d. Two similar filtered-air exposures during the preceding week served as controls. Follow-up O{sub 3} exposures were performed 4 and 7 d after the most recent consecutive exposure. All exposures were performed in an environmental chamber at 31 {degrees}C and 35% relative humidity. The subjects performed moderate exercise (mean ventilation rate of 32 l/min) for 15 min of each half-hour. Responses were measured with spirometry and symptom evaluations before and after each ...
To evaluate a dose conversion factor from the `Working Level of Month` (WLM) of radon to the absorbed dose (mGy), the quality of radon and its progeny was assessed, and exposures controlled for each deposition region were planed as follows: 1) exposure of radon gas to the entire respiratory tract, 2) exposure of `unattached` fractions to the upper respiratory tract, 3) exposure of `attached` fractions onto ultrafine particles to the deep lung, 4) exposure of `attached` fractions onto fine particles to the lower respiratory tract, 5) exposure of `attached` fractions onto coarse particles to the upper respiratory tract. In this preliminary study, a prototype exposure system of radon and its progeny for small rodents was designed. A whole body exposure chamber with a volume of about 0.5 m{sup 3} was used, which it held 20 ...
In Oslo, traffic has been one of the dominating sources of air pollution in the last decade. In one part of the city where most traffic collects, two tunnels were built. A series of before and after studies was carried out in connection with the tunnels in use. Dispersion models were used as a basis for estimating exposure to nitrogen dioxide and particulate matter in two fractions. Exposure estimates were based on the results of the dispersion model providing estimates of outdoor pollutant concentrations on an hourly basis. The estimates represent concentrations in receptor points and in a square kilometre grid. The estimates were used to assess development of air pollution load in the areas, compliance with air quality guidelines, and to provide a basis for quantifying exposure-effect relationships in epidemiological studies. After both tunnels were taken in use, the pollution levels in the study areas were lower than ...
The United States Department of Energy (U.S. DOE) has recently implemented a series of strategic initiatives to address long-term radiological surveillance needs at former U.S. nuclear test sites in the Marshall Islands. The plan is to engage local atoll communities in developing shared responsibilities for implementing radiation protection monitoring programs for resettled and resettling populations in the northern Marshall Islands. Using the pooled resources of the U.S. DOE and local atoll governments, individual radiological surveillance programs have been developed in whole body counting and plutonium urinalysis in order to accurately assess radiation doses resulting from the ingestion and uptake of fallout radionuclides contained in locally grown foods. Permanent whole body counting facilities have been established at three separate locations in the Marshall Islands including Rongelap Atoll (Figure 1). These facilities are operated and maintained by Marshallese technicians with ...
SummaryNanoparticles are increasingly being used in industry. Their potential to cause adverse health effects is due to their very small particles size (less than 100nm). A review is to be carried out to explore a) the use/release of nanoparticles in industry, b) current practices to control exposure and c) the potential levels of workplace exposure. The report will contain a discussion of what is current best practice to control exposure to nanoparticles. It will also indicate where the gaps in kn [continued...]ObjectivesA written report that draws upon disparate sources of available information and uses competent occupational hygiene expertise to form expert opinion on the implications. Key measures will the demonstration reasoned arguments supported by data from both current deliberate manufacturing of nanoparticles and incident nanoparticle production. The report will include all viable occupational ...
There are many sources of population exposures to power-frequency (50/60 Hz) electric and magnetic fields including household appliances and wiring, neighborhood distribution circuits, and high-voltage transmission lines. Bioeffects studies were unable to demonstrate that exposures to power-frequency fields can affect public health. Researcher have likewise been unable to show that the health effects of such exposures are negligible. State and federal regulatory agencies are, therefore, grappling with questions of whether and how to regulate the sitting or design of new extra high-voltage transmission lines so as to control the ground-level fields to which people are exposed. The purpose of this dissertation is to illuminate some of the exposure-related aspects of these question. A taxonomy of the relationship between field encounter and effect is developed to clarify the meaning of terms such as ...
Developing markets in the Pacific Basin depend heavily on the production and export of consumer goods. The generation of hazardous waste as a by-product of industrial production can be linked to adverse health outcomes, such as childhood leukemia, in ways that are presently unknown. In California, exposures resulting from hazardous waste disposal are of concern in the etiology of childhood cancer. Approximately 63% of the 57 hazardous waste sites that the U.S. Environmental Protection Agency (USEPA) included in the national priority list under the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) statute were in the six-county San Francisco Bay area. This area includes California`s Silicon Valley, where a disproportionate majority of these sites are located. Although only one study links hazardous waste disposal to childhood leukemia evidence is accumulating that in utero and maternal pesticide exposures as well as ...
The authors developed an analytical model (intersection model) to estimate the exposure of sea otters (Enhydra lutris), to oil from the Exxon Valdez oil spill. The authors applied estimated and assumed exposure dependent mortality rates to the Kenai Peninsula sea otter population to provide examples of the application of the model in estimating sea otter mortality. The intersection model requires three distinct types of data: (1) distribution, abundance, and movements of oil, (2) abundance and distribution of sea otters, and (3) sea otter mortality rates relative to oil exposure. Initial output of the model is an estimate of exposure of otters to oil. Exposure is measured in amount and duration of oil near an otter`s observed location (intersections). The authors provide two examples of the model using different assumptions about the relation between exposure ...
Maternal exposure to ambient air pollution has increasingly been linked to adverse pregnancy outcomes. The evidence linking this exposure to congenital anomalies is still limited and controversial. This case-control study investigated the association between maternal exposure to ambient particulate matter with aerodynamic diameter less than 10 ?m (PM(10)), sulfur dioxide (SO(2)), nitrogen dioxide, nitric oxide (NO), ozone (O(3)), and carbon monoxide (CO) and the occurrence of congenital heart disease in the population of Northeast England (1993-2003). Each case and control was assigned weekly average (weeks 3-8 of pregnancy) of pollutant levels measured by the closest monitor to the mother's residential postcode. Using exposure as both continuous and categorical variables, logistic regression models were constructed to quantify the adjusted odds ratios of exposure to air pollutants ...
An irradiation head with sample holders is described and measurement geometry is reported. Measurements were made for optimizing the distance between the source and the sample and for optimizing the sample diameter. The optimal distance between the source and the sample does not depend on the collimator diameter. The sample diameter should not exceed 30 - 35 mm. Sensitivity and detection limits were determined for Zn, Pb and Br and calibration curves were plotted. (M.D.) 6 figs., 2 tabs., 4 refs.
This paper describes a method for preparing the sample handling and inlet system of a mass spectrometer for analysis of a subsequent sample following analysis of a previous sample comprising the flushing of the system interior with supercritical CO{sub 2} and venting the interior. The method eliminates the effect of system ``memory`` on the subsequent analysis, especially following persistent samples such as xenon and krypton.
The in vivo toxic effects of hexavalent chromium (20 mg/liter) on hemolymph glucose, tissue glycogen, total free sugars, and active and total phosphorylases of an edible, freshwater crab Barytelphusa guerini were studied. In a 15-day exposure span followed by a 15-day postexposure recovery, the time-course alterations in these constituent segments of the glycogen metabolism indicate an inconsistent depletion in metabolite levels and elevated enzyme activities during exposure period as well as hyperglycemia. An insignificant recovery was observed in these parameters on the 15th day of the postexposure phase.
The High Exposure Facility is a collimated high-level gamma irradiator that is located in the basement of the 318 building. It was custom developed by PNNL back in 1982 to meet the needs for high range radiological instrument calibrations and dosimeter irradiations. At the time no commercially available product existed that could create exposure rates up to 20,000 R/h. This document is intended to pass on the design criteria that was employed to create this unique facility, while maintaining compliance with ANSI N543-1974, "General Safety Standard for Installations Using Non-Medical X-Ray and Sealed Gamma-Ray Sources, Energies up to 10 MeV."
The use of uranium mill tailings in the foundations of dwellings has resulted in indoor radon progeny concentrations and gamma exposures in excess of levels presently allowed for the general public. An account is given of the applications of an epoxy coating on the indoor faces of the concrete foundations of three buildings in Grand Junction, Colorado. Epoxy barriers were shown to be effective for preventing radon influx into structures. Gamma exposure rates must be analyzed to ensure that buildup behind the barrier will not introduce an unacceptable gamma exposure level. The use of a sealant is especially economical in situations where structural integrity may be jeopardized by physical removal of uranium mill tailings. (author).
Indoor air exposures to gaseous contaminants originating in soil can cause large human health risks. To predict and control these exposures, the mechanisms that affect vapor transport in near-surface soils need to be understood. In particular, radon exposure is a concern since average indoor radon concentrations lead to much higher risks than are generally accepted for exposure to other environmental contaminants. This dissertation examines an important component of the indoor radon problem: the impacts of wind on soil-gas and radon transport and entry into buildings. The research includes experimental and modeling studies of wind`s interactions with a building`s superstructure and the resulting soil-gas and radon flows in the surrounding soil. In addition to exploring the effects of steady winds, a novel modeling technique is developed to examine the impacts of fluctuating winds on soil-gas and radon ...
Attention-deficit/hyperactivity disorder (ADHD) is a prevalent neurobehavioral disorder affecting 5% to 10% of children. Although considered to be a highly familial disorder, ADHD heritability estimates of 60% to 80% highlight the considerable role that environmental factors may still play in disorder susceptibility. Proposed ADHD environmental risk factors include prenatal substance exposures, heavy metal and chemical exposures, nutritional factors, and lifestyle/psychosocial factors. This paper reviews the literature published in 2010 investigating the association between environmental risk factors and ADHD or related symptomatology. Sources of risk factor exposure and the proposed mechanism by which each exposure is linked to ADHD-related neurobehavioral changes are also reported. Metho...
Hypersensitivity Pneumonitis (HP) is an interstitial lung disease that develops following repeated exposure to inhaled environmental antigens. The disease is characterized by alveolitis, granuloma formation...Full Text Available
BackgroundElementary schools represent both a source of childhood sun exposure and a setting for educational interventions.MethodsSun Protection...Full Text Available
PurposeThis study evaluates changes in recall of combat exposures over the first year after return from deployment. The research purpose is to assess whether recall of combat exposures is consistent at different time points; if not, what demographic and/or PTSD symptom risk factors exist for any directional instability. MethodsSurveys completed by soldiers at 3, 6, and 12 months post-Operation Iraqi Freedom (OIF) deployment were linked for longitudinal analysis in a previous study in which three matched datasets were created: 3-6 months (N = 768), 6-12 months (N = 341), and 3-12 months (N = 445). Post-traumatic stress disorder (PTSD) was assessed by using the National Center for PTSD Checklist. The reliability of recall for 36 combat exposures was quantified. The effects of demographics an...
The somatic and genetic radiation exposure of patients undergoing Digital Subtraction Angiography (DSA) and traditional Film Arteriography (FA) of cranial, cervical, thoracic and abdominal vascular territories are compared. The radiation doses absorbed within the critical organs - red bone marrow, lung, thyroid gland and female breast - and in the gonads were measured using an anthropomorphic Alderson phantom. A Somatic Dose Index was calculated in order to estimate the somatic radiation risk. The somatic radiation exposure depends upon the location of the critical organs with respect to the entrance site of the x-ray beam, and can be reduced by an appropriate choice of the angiographic projection. Under this condition, the radiation exposure of the patient during DSA can be lower than during FA. For renal DSA an a.p. projection, the use of an abdominal compression device and careful caudal shielding of the field are ...
This study was intended to help explain individual differences in susceptibility to irritant effects of ozone (O3), by determining whether prior ambient O3 exposures and/or recent acute respiratory illness modified response to laboratory O3 exposures. Response was measured in terms of lung function changes and irritant symptoms. Initially, 59 adult volunteer Los Angeles area residents underwent screening exposures in spring, before the season of frequent high ambient O3 levels. Unusually responsive and nonresponsive individuals (N = 12 and 13 respectively) underwent followup exposures in autumn (late in the high-O3 season) and in winter (low-O3 season). All exposures were to 0.18 ppm O3 for 2 hr with intermittent heavy exercise at 31 degrees C and 35% relative humidity. Nonresponders tended to remain nonresponsive throughout. In fall, responders had lost much of their reactivity, as ...
The Agency for Toxic Substances and Disease Registry (ATSDR) is a public health agency with responsibility for assessing the public health implications associated with uncontrolled releases of hazardous...Full Text Available
BackgroundPolybrominated diphenyl ethers (PBDEs) are widely used flame retardant compounds that are persistent and bioaccumulative and therefore have become ubiquitous environment...Full Text Available
The relative transport capabilities of the cells of the root periphery and cortex were investigated using a variety of experimental techniques. Brief (30 seconds to 1 minute) exposures with the penetrating...Full Text Available
For some neurotoxic chemicals, neurobehavioral effects are now considered to be among the most sensitive end points yet detected, particularly if exposures occur during critical windows of vulnerability....Full Text Available
The effects of exposure to sublethal levels of microwaves were studied. Young albino rats of both sexes were exposed for 60 days to 7.5-GHz microwaves (1.0-KHz square wave modulation, average power 0.6 mW/cm2) for 3 h daily. During and after microwave exposure several physiological parameters were measured in both control and exposed animals. It was found that the animals exposed to microwaves tended to eat and drink less and thus showed a smaller gain in body weight. Some of the hematological parameters and organ weights were also significantly different. It is proposed that a nonspecific stress response due to microwave exposure and mediated through the central nervous system is responsible for the observed physiological changes.
BackgroundBisphenol A (BPA) is widely used in the manufacture of polycarbonate plastics, including infant formula bottles.ObjectivesBased on the...Full Text Available
AIMSTo develop a population pharmacokinetic–pharmacodynamic model to describe the occurrence and severity of bleeding or bruising as a function of enoxaparin exposure.METHODSData...Full Text Available
Weaning of beef calves is usually done abruptly and early compared to the natural weaning of the species, and is associated with simultaneous exposure of calves to a range of social and environmental...Full Text Available
Ultimate Compressive Strength of Short Sheet - Stringer Panels With Special. Reference to the Influence of the Riveted Connection Between Sheet and Stringer ...
The herbicide atrazine is a known immunotoxicant and an inhibitor of human natural killer (NK) cell lytic function. The precise changes in NK cell lytic function following atrazine exposure have not been fully elucidated. The current study identifies the point at which atrazine exerts its affect on the stepwise process of human NK cell-mediated lyses of the K562 target cell line. Using intracellular staining of human peripheral blood lymphocytes, it was determined that a 24-h in vitro exposure to atrazine did not decrease the level of NK cell lytic proteins granzyme A, granzyme B or perforin. Thus, it was hypothesized that atrazine exposure was inhibiting the ability of the NK cells to bind to the target cell and subsequently inhibit the release of lytic protein from the NK cell. To test t...
Advances in geographic information system (GIS) technology, developed by geographers, provide new opportunities for environmental epidemiologists to study associations between environmental exposures...Full Text Available
We report on recent studies of the effects of 50 keV focused ion beam (FIB) exposure on MOS transistors. We demonstrate that the changes in value of transistor parameters (such as threshold voltage, V{sub t}) are essentially the same for exposure to a Ga+ ion beam at 30 and 50 keV under the same exposure conditions. We characterize the effects of FIB exposure on test transistors fabricated in both 0.5 {micro}m and 0.225 {micro}m technologies from two different vendors. We report on the effectiveness of overlying metal layers in screening MOS transistors from FIB-induced damage and examine the importance of ion dose rate and the physical dimensions of the exposed area.
The purpose of this note is to provide guidance to those who have duties under the Health and Safety at Work Act and other relevant legislation. It gives guidance on the practical application of legislation, concerning radiotherapy equipment. Two particular issues arise out of the requirements of Regulation 33 of the Ionising Radiations Regulations 1985 (IRR85) in relation to equipment which is used for medical exposures. These are the requirement to select, install and maintain this type of equipment in such a way that it is capable of restricting, so far as reasonably practicable, the medical exposure of any person where this is compatible with the intended clinical purpose, including the need to ensure that equipment used for radiotherapy is properly calibrated, and the requirement to notify the Health and Safety Executive (HSE) when an incident occurs involving a malfunction or defect in any 'radiation equipment' which ...
The report contains general information on aluminium and aluminium compounds concerning the existing standards, emissions, exposure levels and effect levels. The document is to be considered as a first evaluation to be used for the national discussion dur...
Increased concern about potential health problems related to exposure to nonionizing electromagnetic fields (EMF) has occurred recently. The most recent epidemiological studies have dealt mainly with effects of extremely low frequency EMF on fetal development and cancer. This paper summarizes noteworthy aspects or recent reviews and studies in this area of research. There has been increased concern recently about potential health problems related to exposure to nonionizing electromagnetic fields (EMF). Although some questions have been raised concerning exposure to radiofrequency radiation (at frequencies up to 300 GHz), the major focus has been on fields of extremely low frequency (especially 60 Hz). The most recent epidemiologic studies have dealt mainly with effects of extremely-low-frequency EMF on fetal development and with the initiation or promotion of cancer.
Six different groups of non-smoking young male subjects were studied separately for 18 consecutive days each in a closed controlled-environmental human exposure chamber. Each group was subjected to a 5-day control period in fresh air followed successively by an 8-day period of continuous exposure to 50 ppm, 15 ppm or 0 ppm (control) by volume of carbon monoxide (CO) in air, and a 5-day recovery period in fresh air. The subjects performed a 1-h auditory vigilance task every day at the same time of day in a fixed qualitative, quantitative, and temporal relationship with food intake, consumption of stimulating beverages, physical activity, and sleep. It was concluded that such CO exposure, involving the continuous carriage of carboxyhaemoglobin loads up to 7%, was without significant effect on auditory vigilance.
BackgroundThe National Cancer Institute has concluded that exposure to smoking in movies causes adolescent smoking and there are similar results for young adults.Full Text Available
SOME SCIENTISTS ALLEGE that exposure to electric and magnetic fields generated by electric power delivery systems is responsible for certain cancers (particularly among children), reproductive dysfunction,...Full Text Available
ObjectiveTo determine whether accounting for the time dynamics of diabetes exposure will change the risk estimates for colorectal cancer.Full Text Available
After having discussed the peculiarities of children in X-ray diagnosis the application of the effective as well as the mean equivalent doses as to the determination of the radiation exposure in children is represented. In using computerized tomograms to determine position and extent of an organ the exposure by repeated X-raying was calculated referring to the entrance dose. Entrance dose measurements for all types of X-ray examination in hospitals and ascertainments of the frequency of radiograms in 20 X-ray departments were used to determine per capita and collective doses, resp., in several age groups. Alltogether, the per capita dose of children in the GDR amounts to 30% of that of adults. Conclusions were drawn as to taking measures to further reduction of radiation exposure: (1) Technical measures, such as positioning of patients, shielding of organs, quality assurance; (2) elaboration of regulations concerning the ...
Cell cultures were prepared from lung tumors occurring in beagles following exposure to inhaled plutonium. Morphologic and growth characteristics of two of these cell lines are described.
Due to the use of a limited number of species and subchronic exposures, current ecological hazard assessment processes can underestimate the chronic toxicity of environmental contaminants resulting...Full Text Available
Recent legislative changes in both Europe and the USA have increased the responsibility of drug developers to purposefully study the agents they market in children so that specific dosing recommendations can be made to assist clinicians in their use. Typically, clinicians use empirical- or experiential-based rationales for selecting the dose to use in children, generally in a manner that attempts to achieve the same dose-exposure or pharmacokinetic profile in children as in adults. However, whether this approach achieves the necessary dose exposure or exposure effect needed may not be systematically explored during off-label use. This creates the opportunity for under- or over-exposure in children, particularly in very young children (i.e., less than 2 years old) where a combination of fac...
A field study of 89 refrigerator repairmen was carried out to ascertain whether occupational exposure to fluorocarbons induces cardiac arrhythmia. The concentrations of fluorocarbons in the breathing...Full Text Available
Studies were conducted in northern Bohemia to simultaneously evaluate personal exposures to air pollution in the form of respirable particles containing polycyclic aromatic hydrocarbons (PAHs) and biomarkers...Full Text Available
Measurement of serum biochemical parameters in response to metal exposures can be especially useful to help identify target organs of toxicity as well as the general health status of animals. Oreochromis niloticus were exposed to 5.0?mg/L?Zn, 1.0?mg/L?Cd, and 5.0?mg/L?Zn?+?1.0?mg/L?Cd mixture for 7 and 28?days, and alterations in serum enzyme activities and ion levels were measured. Significant changes in all the biochemical parameters were found to be time dependent. Following metal exposure, alkaline phosphatase activity was elevated at both exposure periods. No changes in activities of lactate dehydrogenase and lipase were observed in response to single or combined Zn and Cd exposure at 7?days while they increased at 28?days. Fish exposed to metals showed a decrease in cholinesterase ac...
SummaryWe consider the problem of estimating the effect of exposure on multiple continuous outcomes, when the outcomes are measured on different scales and are nested within multiple...Full Text Available
... radiation during clinical therapy and exposures due to radiation accidents or attacks, in which the doses are uncontrolled ... only be used off-label in victims of radiation accidents or attacks. The idea...
An exposure chamber is described for the quantifiable addition of fine and ultrafine aerosol particulate matter directly to cells and used to demonstrate the in vitro cytotoxicity of fine 1,4-naphthoquinone particles to murine lung epithelial cells. The electrostatic particulate dosage and exposure system (EPDExS) operates on the principle of electrostatic precipitation and is shown to deposit fine and ultrafine aerosol particles directly to cells with 100% efficiency for particle diameters in the range of 40-530nm. This range is not limited by the EPDExS, but rather by the aerosolization method used for this study. Numbers of particles deposited onto the cells are counted with a condensation particle counter, negating any need to calculate or estimate particle exposure. The process of par...
With more women entering the labor market, concern about adverse effects of occupational exposure on reproductive health has been increasing. Of special importance are those agents which might cause...Full Text Available
A multiple probe approach of implanting microdialysis probes into each separate tissue layer would better represent sampling from the stomach. Presently, microdialysis sampling experiments are...Full Text Available
Feed samples from 94 cases involving fungal contamination and suspected mycotoxicosis of farm animals in western Canada were examined during 1982-1994 to assess the incidence of mycotoxins. Samples...Full Text Available
Invasive prenatal testing has become an important way to evaluate fetuses at increased risk for hereditary disorders. In utero sampling of fetal skin, liver, and muscle may be required to diagnose before-birth...Full Text Available
The purpose of this report is to describe the sampling approaches, modifications made to the 100 Area and 300 Area component of the RCBRA Sampling and Analysis Plan, summarize validation efforts, and provide sample identification numbers.
The paper present the results of the study on D.U. (depleted uranium) contamination in the environment and possible effects on animal healths in the region o f Bujanovac. Samples of soil, feed, leaves, grass, lichen, moss, honey and water were collected randomly in 2003/2004 in the vicinity of the target area (500-1000 m) and 5 km from the target area. Activity of the radionuclides ({sup 226}Ra, {sup 232}Th, {sup 40}K, {sup 210}Pb, {sup 238}U, {sup 235}U, {sup 137}Cs, {sup 7}Be) in soils, grass, lichen, moss and honey was determined on Hp Ge detector (Canberra, relative efficiency 23%) by standard gamma spectrometry. Total alpha and beta activity in water was determined on proportional alpha/beta counter (Canberra 2400, efficiency for alpha emitters 11%, efficiency for beta emitters 30%). Non significantly higher values of concentrations of {sup 226}Ra, {sup 232}Th, {sup 238}U and {sup 235}U were measured in the immediate vicinity of the targeted site, but {sup ...
The aims of this study were (a) to assess blood cadmium (B-Cd) concentrations and to establish a tentative reference interval; (b) to identify significant determinants of B-Cd, in a population from Umbria, Central Italy, which was not occupationally exposed to cadmium (Cd). Four hundred and thirty-four healthy blood-donors volunteered to answer a questionnaire and provide a blood sample for B-Cd analysis, which was performed by graphite furnace atomic absorption spectrophotometry. Blood Cd concentrations ranged from non-detectable values, i.e. below 0.1 {mu}g/l up to 3.4 {mu}g/l and were not normally distributed. The median values and the 95th percentiles were 0.7 and 2.0 {mu}g/l, respectively. Concentrations of B-Cd were more than double in smokers than in non-smokers, median values being 1.1 {mu}g/l and 0.5 {mu}g/l, respectively. In current smokers, B-Cd values correlated with the number of cigarettes smoked daily (r{sub s}=0.40, P=0.0001) and with the cumulative ...
Many epidemiological studies have investigated residential exposure to extremely-low-frequency magnetic field (ELF-MF) for children, but exposure at schools where children may stay up to 8 h every weekday was rarely considered. Between March and June 2004, we carried out a field study in Taipei City and County of northern Taiwan to explore ELF-MF exposure pattern among children at schools with high voltage transmission lines (HVTL) running through the campuses. One hundred and one children attending 14 schools with nearby HVTL (exposed group) and 123 children of 18 schools at least 100 m away from HVTL (unexposed group) were monitored for 24-hour personal ELF-MF exposure. Selected classrooms and playgrounds within the buffer regions (i.e., within 30 m of HVTL) and those away from the buffer regions were also assessed, using spot measurements, to determine the extent to which HVTL may contribute to the ...
The Rotary Mode Core Sample System (RMCSS) is used to obtain stratified samples of the waste deposits in single-shell and double-shell waste tanks at the Hanford Site. The samples are used to characterize the waste in support of ongoing and future waste remediation efforts. Four sampling trucks have been developed to obtain these samples. Truck I was the first in operation and is currently being used to obtain samples where the push mode is appropriate (i.e., no rotation of drill). Truck 2 is similar to truck 1, except for added safety features, and is in operation to obtain samples using either a push mode or rotary drill mode. Trucks 3 and 4 are now being fabricated to be essentially identical to truck 2.
Removal Sampling is an easy-to-use Windows program which calculates population statistics from removal trapping experiment data. Using maximum likelihood methods it ... ...
Rationale and ObjectivesSample-size estimation is an important consideration when planning a receiver operating characteristic (ROC) study. The aim of this work was...Full Text Available
Here we describe the fabrication, optimization, and application of a microfluidic device that integrates microdialysis (MD) sampling, microchip electrophoresis (ME), and electrochemical detection...Full Text Available
The National Food and Nutrient Analysis Program (NFNAP) was implemented in 1997 to update and improve the quality of food composition data maintained by the United States Department of Agriculture (USDA). NFNAP was designed to sample and analyze frequently consumed foods in the U.S. food supply using statistically rigorous sampling plans, established sample handling procedures, and qualified analytical laboratories. Methods for careful handling of food samples from acquisition to analysis were developed to ensure the integrity of the samples and subsequent generation of accurate nutrient values. The infrastructure of NFNAP, under which over 1500 foods have been sampled, mandates tested sample handling protocols for a wide variety of foods. The majority of these foods were categorized into ...
A possibility is considered or reducing the surface heterogeneity effect of an item being tested on the result of radiation flaw detection by means of signal delay of one of detectors in a two-channel radiometric flaw detector. The exposure of a translationally moving item has been studied as well as an external exposure of a rotating hollow item.
The Ra, Th, and K-40 content of the most important phosphate fertilizers used and authorized in the FRG was determined by #gamma#-spectroscopy. The results, together with statistical data on the consumption and use of fertilizers, were used for an estimation of the contribution of #gamma#-radiation from phosphate fertilizers to the external population exposure in the FRG. (orig./AK).
This chapter is concerned with standards and guidances for limiting radiation exposures. It is divided into three sections, each of which has several parts. Section 1: Ionizing Radiation -- Standards and Guidances Applicable to the Public: Part A, Radiation Protection Standards; Part B, Environmental Radiation Standards; Part C, Exempt Levels of Radioactivity; Part D, Protective Action Guides for Accidents. Section 2: Ionizing Radiation -- Standards Applicable to the Workplace. Section 3: Medical and Other Standards.
Due to the large number of chemicals in commerce without adequate toxicity characterization data, coupled with an ineffective federal policy for chemical management in the United States, many states are grappling with the challenge to identify toxic chemicals that may pose a risk to human health and the environment. Specific populations (e.g., children, elderly) are particularly sensitive to these toxic chemicals. In 2008, the Children's Safe Product Act (CSPA) was passed in Washington State. The CSPA included specific requirements to identify High Priority Chemicals (HPCs) and Chemicals of High Concern to Children (CHCCs). To implement this legislation, a methodology was developed to identify HPCs from authoritative scientific and regulatory sources on the basis of toxicity criteria. Another set of chemicals of concern was then identified from authoritative sources, based on their potential exposure to children. Exposure potential was ...
Exposure of teachers of physics to X-radiation emitted by instruments which are used for demonstrating rarefied gas discharges during physics lessons at secondary schools is discussed. The measurements performed provide an explicit evidence that an effective, annual exposure dose under the most unfavorable conditions does not exceed admissible levels according to Polish regulations pertaining to persons non-occupationally exposed to ionizing radiation. (author). 3 refs,1 fig.
Highlights of the meeting are briefly summarized in this paper. Most of the papers presented at the meeting dealt with remediation and pollution prevention practices. A major focus of the technical sessions was on the identification of pollution sources. Identification of exposures to specific chemicals with disease outcomes was also discussed. Other papers focused on ecological exposures and their effects on wildlife to identify the presence of contaminants. 4 refs.
On the basis of legally provided area dose measurements and time records of fluoroscopic examinations during the operation, radiation doses to medical personnel and patients are evaluated. Adequate radiation protection measures and a careful behaviour in the operating room keep the radiation exposure to the personnel below the maximum permissible exposure. Taking into account the continuous personnel radiation monitoring and medical supervision, radiation hazards in the operating room can be considered low.
Short and long-term pulmonary response to inhaled nickel hydroxide nanoparticles (nano-Ni(OH)2, CMD = 40 nm) in C57BL/6 mice was assessed using a whole body exposure system. For short-term...Full Text Available
Accumulation of "8"5Kr in arterial blood of sheep occurs within 10 min of inhalation exposure initiation, and disappears by 30 min after exposure termination. As reported for other species, "8"5Kr concentrations in fat were approximately 10 times those in other tissues.
This report revises estimates of population exposure to external natural background made by D. T. Oakley in 1972. The revisions include more recent estimates of dose equivalents from cosmic rays, use of 1970 U.S. census data, and corrections for building shielding and for self-shielding in the body. The dose equivalents calculated are those from cosmic rays and terrestrial radiation, and do not include doses from natural radioactive materials in the body.
Low-level lead exposure during early childhood has long been associated with altered neurocognitive development and diminished cognitive functions. Over nine thousand U.S. industrial facilities...Full Text Available
This paper introduces an occupational exposure information system in detail, which is developed and in operation presently by Daya Bay nuclear power plant. It is presented in the paper that individual dose monitoring items and method, design and classification of database configuration, statistics and analysis of individual dose, and management of staff entering and exiting controlled area. The system is instructive to analysing individual dose and optimizing radiation protection measures. (authors)
Daily exposures of adult beagle dogs to inhaled radon daughters plus uranium ore dust, with and without concurrent cigarette smoking, for 2 to 5-1/2 yr have produced massive pulmonary fibrosis and severe emphysema. The cumulative exposure doses are similar to those associated with a 5-fold or greater increase in death rate of uranium miners due to chronic respiratory insufficiency, including pneumoconiosis, pulmonary fibrosis, and emphysema.
Laser safety standards and eye protection (filters) are designed to limit ocular exposures to prevent retinal lesions, yet eyesafe laser exposures can disrupt vision by causing glare and flashblindness. Protective filters can have opposing effects on vision function. They reduce laser exposures but also reduce task luminance and contrast. Filters alone may interfere with vision and consequently reduce work safety and performance. It is therefore important to be able to predict the effects of both laser exposures and protective filters to assess trade-offs between protection and visual function. This paper briefly reviews the methods, concepts, and experimental database used in our laboratory to predict laser, filter, and laser-plus-filter effects on tasks involving visual detection. The modeling approach uses estimates of the spatial distribution of light in the retinal image of the laser source to ...
Objectives: We have previously shown that chronic exposure to ambient fine particulate matter (less than 2.5 ?m in aerodynamic diameter, PM(2.5)) pollution in conjunction with high-fat diet induces insulin resistance through alterations in inflammatory pathways. In this study we evaluated the effects of PM(2.5) exposure over a substantive duration of a rodent's lifespan and focused on the impact of long-term exposure on adipose structure and function.Methods and Results: C57BL/6 mice were exposed to PM(2.5) or filtered air (FA) (6 hours/day, 5 days/week) for duration of 10 months in Columbus, OH. At the end of the exposure, PM(2.5)-exposed mice demonstrated insulin resistance (IR) and a decrease in glucose tolerance compared with the FA-exposed group. Although there were no significant differences in circulating cytokines between PM(2.5)- and FA-exposed groups, circulating adiponectin and leptin were ...
Beagle dogs given a single inhalation exposure to "2"3"9Pu(NO_3)_4 are being observed for life-span dose-effect relationships. Over half of the dogs planned for "2"3"9Pu(NO_3)_4 exposure have been exposed and the remaining dogs will be exposed as they reach adult age.
Subchronic exposure to pharmacological levels of estrogenic compounds, including 17 beta-estradiol, diethylstilbestrol, and alpha-dienestrol, significantly increased the mortality of B6C3F1 female mice...Full Text Available
Occupational and environmental exposure to organic ligands, solvents, fuel hydrocarbons, and polychlorinated biphenyls are linked with increased risk of hematologic malignancies. DOE facilities and waste sites in the U.S. are contaminated with mixtures of potentially hazardous chemicals such as metals, organic ligands, solvents, fuel hydrocarbons, polychlorinated biphenyls and radioactive isotopes. A major goal of this project was to establish linkage between chemical/radiation exposure and induction of genomic damage in target populations with the capability to undergo transformation.
The purpose of the present work was to establish the flammability limits of hydrogen in air for upward vertical flame propagation at elevated temperatures up to 350 deg and atmospheric pressure in a conventional stainless steel test tube apparatus, and to investigate the extent to which a prolonged exposure (i.e., residence time) of the mixture to elevated temperatures before spark ignition may influence the value of the flammability limits. 9 refs.
Previous studies demonstrated that perinatal exposure to polybrominated diphenyl ethers (PBDEs), a major class of brominated flame retardants, may affect thyroid hormone (TH) concentrations by inducing...Full Text Available
The past three years of work for the Air Force Office of Scientific Research has resulted in the development of a congenic mouse model of JP-8 jet fuel exposure, the role of substance P in the JP-8 jet fuel-induced lung injury process, and development of ...
Radon in the home is the main source of exposure to ionising radiation for most people. In 1990 the National Radiological Protection Board issued revised advice to the United Kingdom Government on standards of protection against radon in the home. A description is offered of the survey work being undertaken by the Board which includes radiation measurements of thousands of homes in the United Kingdom. (author).
Cadmium (Cd) exposure causes glucosuria (glucose in the urine). Previously, it was shown that Cd exposure of primary cultures of mouse kidney cells (PMKC) decreased mRNA levels of the glucose...Full Text Available
Environmental and occupational exposures to heavy metals such as methylmercury (MeHg) and cadmium (Cd) pose significant health risks to humans, including neurotoxicity. The underlying mechanisms of...Full Text Available
This Guideline provides a set of procedures for the measurement of organic contaminants and particles in producer gases from biomass gasifiers. The procedures are designed to cover different gasifier types (updraft or downdraft fixed bed or fluidised bed gasifiers), operating conditions (0 - 900C and 0.6-60 bars) and concentration ranges (1 mg/m{sub n}{sup 3} to 300 g/m{sub n}{sup 3}). The Guideline describes a modular sampling train, and a set of procedures, which include: planning and preparation of the sampling, sampling and post-sampling, analysis, calculations, error analysis and reporting. The modular sampling train consists of 4 modules. Module 1 is a preconditioning module for isokinetic sampling and gas cooling. Module 2 is a particle collection module including a heated filter. Module 3 is a tar collection module with a gas quench (optionally by ...
Two sources of ultraviolet (UV) radiation with peak wavelengths in the UV-C or UV-B ranges were compared for their ability to sterilize contact lenses infected with Pseudomonas aeruginosa, Streptococcus pneumoniae, Acanthamoeba castellani, Candida albicans, and Aspergillus niger. Also examined was the effect of prolonged UV light exposure on soft and rigid gas permeable (RGP) contact lenses. The UV-C lamp (253.7 nm, 250 mW/cm2 at 1 cm) was germicidal for all organisms within 20 minutes but caused destruction of the soft lens polymers within 6 hours of cumulative exposure. UV-C caused damage to RGP lenses in less than 100 hours. The UV-B lamp (290-310 nm, 500 mW/cm2 at 1 cm) was germicidal for all organisms tested (except Aspergillus) with a 180-minute exposure and caused less severe changes in the soft lens polymers than did the UV-C lamp, although cumulative exposure of 300 hours did substantially ...
Two sources of ultraviolet (UV) radiation with peak wavelengths in the UV-C or UV-B ranges were compared for their ability to sterilize contact lenses infected with Pseudomonas aeruginosa, Streptococcus pneumoniae, Acanthamoeba castellani, Candida albicans, and Aspergillus niger. Also examined was the effect of prolonged UV light exposure on soft and rigid gas permeable (RGP) contact lenses. The UV-C lamp (253.7 nm, 250 mW/cm2 at 1 cm) was germicidal for all organisms within 20 minutes but caused destruction of the soft lens polymers within 6 hours of cumulative exposure. UV-C caused damage to RGP lenses in less than 100 hours. The UV-B lamp (290-310 nm, 500 mW/cm2 at 1 cm) was germicidal for all organisms tested (except Aspergillus) with a 180-minute exposure and caused less severe changes in the soft lens polymers than did the UV-C lamp, although cumulative exposure of 300 hours did substantially ...
This paper addresses the quantification of human exposure to volatile organic compounds (VOC's) as a result of mass transfer from tap water to indoor air. A three-compartment model is developed and used to simulate the 24-h concentration profile within the shower, bathroom, and remaining household volumes of a dwelling. Mass transfers from water to air are derived from measured data for radon and adjusted to account for the difference in mass-transfer properties for VOC's. A preliminary data base for household parameters is used to calculate a range of concentrations and human exposures in U.S. dwellings. The model is used to estimate exposure factors for seven compounds-chloroform, ethylene dibromide, dibromo-chloropropane, methylchloroform, perchloroethylene, trichloroethylene, and carbon tetrachloride. The calculated ratio of indoor-air exposure to tap water concentration is compared to measured ...
A suspension of bone marrow cells from femurs of female (CBA . C57B1)F1 mice was exposed to 2450 MHz CW microwaves in a specially designed waveguide exposure system. The temperature of the suspension rose, during exposure to microwaves, from 20/sup 0/C to 45/sup 0/C, and at an interval within 20/sup 0/C to 45/sup 0/C the number of haemopoietic stem cells (CFUs) was determined by the spleen exocolony method. The time of exposure of bone marrow cells to each temperature studied was 20 s. Control suspensions of bone marrow cells were exposed to a water bath temperature. There were no significant effects of the CFUs with the water bath temperature, while after exposure to microwaves the number of spleen colonies was elevated with a nadir at the temperature of 37/sup 0/C. With a microwave-induced increase of the temperature above 41/sup 0/C the number of CFUs in the bone marrow suspension decreased. The ...
The genetically significant dose (GSD) is an index variable which exclusively allows to describe the genetic risk in the progeny of a population due to the application of ionizing radiation and radioactive substances in one part of this population. It may result in wrong interpretation of population exposure at increasing incidence of examinations in a population involving ionizing radiation and radioactive drugs at simultaneously increasing application of alternative methods in children and adolescents owing to the fact that it indicates a downward trend although somatic exposure of this population has increased. Therefore, it is recommended to state both the GSD and the level of somatic radiation exposure of the population taken from the individual sources for the comparison and assessment of radiation exposure from various sources in future. Although the somatically significant dose constitutes the ...
Contaminated wood treatment sites can result in adverse health effects to nearby residents. Environmental exposure can be estimated by measuring concentrations of pollutants in air, water, food, or wipe tests. This environmental exposure value can be used as a surrogate to estimate individual exposure. The objective of this study was to determine whether or not pentachlorophenol (PCP) could be found in potentially exposed residents and if the dioxin levels are consistent with PCP exposure. A further objective of the study was to determine whether or not PAH-DNA adducts could be found in the potentially exposed residents. We present results of biomonitoring studies in residents living near a wood treatment plant that used coal-derived creosote and PCP to process and treat wood for over 100 years. The plant was built in 1904 and used creosote and PCP. Creosote is a complex mixture that contains numerous ...
A procedure for the determination of lead in soil samples by "2"0"3Pb radioisotope dilution substoichiometric method is described. Japan NIES No.2 river clay standard sample and 83-40 Tibet soil standard sample were determined. The obtained values were in good agreement with reference values. The standard deviation of the method was less then 5%. Detection limit was about 0.1 #mu#g Pb.
The applicability of the radionuclide X-ray fluorescence analysis (RXFA) for qualitative and quantitative evaluation of environmental plant samples is discussed and examples of determination of Mn, Fe, Ni, Cu, Zn, Pb in samples of apple trees are given. The instrumentation, the standard and sample preparation are also presented.
We describe a procedure for correcting the systematic errors in the Moessbauer f-factor measurement due to non-homogeneous effective thickness of the sample. To be more precise, we show that, if the mass of the sample is determined by means of X- or {gamma}-ray absorption, it is possible to establish experimental conditions so that the error on f due to material non-homogeneity in the sample is minimized.
This sampling and analysis plan (SAP) identifies characterization objectives pertaining to sample collection, laboratory analytical evaluation, and reporting requirements for vapor samples obtained during the operation of mixer pumps in tank 241-AZ-101. The primary purpose of the mixer pump test (MPT) is to demonstrate that the two 300 horsepower mixer pumps installed in tank 241-AZ-101 can mobilize the settled sludge so that it can be retrieved for treatment and vitrification. Sampling will be performed in accordance with Tank 241-AZ-101 Mixer Pump Test Data Quality Objective (Banning 1999) and Data Quality Objectives for Regulatory Requirements for Hazardous and Radioactive Air Emissions Sampling and Analysis (Mulkey 1999). The sampling will verify if current air emission estimates used in the permit application are correct and provide information for future ...
This study illustrates the way to perform protocols, collect samples, and conduct laboratory analyses in order to characterize the physical properties of wood used in the industrial sector of the Valle de Aburra metropalitan area and the gains obtained by characterizing the properties of the most frequently used woods. In this investigation some of the most important sampling parameters are presented, such as taking samples in piles or accumulations of waste, handling of these samples in the laboratory and others of great importance such as the ignition point. the proposed methodology is based upon some of the international astm coal norms, for the similarity it has with wood and for the lack of information on sampling this type in wood
This paper describes a novel Fourier transform infrared (FTIR) spectroscopic method that can be used to rapidly screen soil samples from potentially hazardous waste sites. Samples are heated in a thermal desorption unit and the resultant vapors are collected and analyzed in a long-path gas cell mounted in a FTIR. Laboratory analysis of a soil sample by FTIR takes approximately 10 minutes. This method has been developed to identify and quantify microgram concentrations of explosives in soil samples and is directly applicable to the detection of selected volatile organics, semivolatile organics, and pesticides.
Objective: To explore the feasibility of real-time monitoring exposure dose and image quality by using the data stored in the DICOM image archive of direct digital radiography system. Methods: Model TO. 16 was exposed, the current increased gradually from 0.5 to 125 mAs. The displayed number of model A( diameter 11.1 mm), D (diameter 4.0 mm) and J( diameter 0.7 mm) were recorded, and the detect factors (H_T) was also calculated. Images were sent to workstation before the end of DR examination. An automatic procedure was implemented to extract dose data and exposure parameters from the DICOM header file. Maximum, minimum and 3rd quartile values were preinstalled. Mean values exceeding the threshold trigger alarm signal to guide radiologist to explore the cause. Results: When the current of point A was less than 10 mAs and the current of point D and J were less than 16 mAs, the detect factor (H_T) increased with the rise of current. While point A ...
The effects of different exposure concentrations of palladium (Pd) on relative metallothionein (MT) response and bioaccumulation were investigated in zebra mussels (Dreissena polymorpha). The mussels were exposed to 0.05, 5, 50, and 500 ?g/L Pd2+ for 10 weeks under controlled temperature and fasting conditions. Relative MT contents were assessed by a modified Ag-saturation method, which allows to discriminate between MT bound to Pd (Pd-MT) and MT bound to unidentified metals (Ag-MT). Determination of metal contents resulted from atomic absorption spectrometry following a microwave digestion. For unexposed mussels and mussels exposed to 0.05 ?g/L Pd no metal accumulation could be detected. All other exposure concentrations resulted in detectable Pd accumulation in mussels with final tissue concentrations of 96 ?g/g (500 ?g/L), 45 ?g/g (50 ?g/L), and 9 ?g/g (5 ?g/L). Compared with initial levels Pd-MT concentrations at the end of the ...
In our previous study, we have estimated the level of human exposure to dioxins (PCDDs, PCDFs, and Dioxin like PCBs) in Japan based on dioxins monitoring data and results of total diet studies (TDS) in fiscal 2000 (April 2000- March 2001). It has been reported that the national PCDDs/DFs emission in 2001 against the 1997 level has been reduced by approximately 77% In addition, reduction of environmental levels was reported. The enforcement of Japan's Law Concerning Special Measures against Dioxins has significant impact on the reduction of the average dioxins concentrations in the ambient air. Therefore, the transitions of Japanese dioxins exposure levels in recent years are worthy of attention. In order to determine exposure level in fiscal 2001, collection and compilation for surveillance results derived from the regular environmental monitoring under the law as well as other dioxins surveys by national and local ...
Perinatal exposure to cadmium (Cd) or methylmercury (MeHg) results in impaired neurodevelopment. Thyroid hormone is essential for normal brain development. However, the issue whether Cd or MeHg, especially at low doses, interrupts thyroid hormone action remains to be investigated. In the present study, effects of perinatal exposure to low levels of Cd or MeHg on thyroid hormone metabolism were examined using metallothionein I and II (MT-I/II) null or wild-type neonatal mice. Dams were exposed to 10 mg/L water of Cd or 5 mg/kg chow of MeHg from gestational day 0 to post-natal day 10 (PND 10). Sera, livers and brains were collected from neonates on PND 10. Iodothyronine deiodinase activities and serum thyroxine (T4) concentrations were measured. MeHg exposure failed to induce changes in serum T4 levels and liver type 1 deiodinase (D1) and brain type 2 deiodinase (D2) activities regardless of the MT genotype. However, ...
Applicability of a model to estimate radiofrequency electromagnetic field (RF-EMF) strength in households from mobile phone base stations was evaluated with technical data of mobile phone base stations available from the German Net Agency, and dosimetric measurements, performed in an epidemiological study. Estimated exposure and exposure measured with dosemeters in 1322 participating households were compared. For that purpose, the upper 10th percentiles of both outcomes were defined as the 'higher exposed' groups. To assess the agreement of the defined 'higher' exposed groups, kappa coefficient, sensitivity and specificity were calculated. The present results show only a weak agreement of calculations and measurements (kappa values between -0.03 and 0.28, sensitivity between 7.1 and 34.6). Only in some of the sub-analyses, a higher agreement was found, e.g. when measured instead of interpolated geo-coordinates were used to calculate the ...
Radioactive waste shipping and receiving facilities presently planned for commercial and defence high level nuclear waste will handle waste packages at frequencies far in excess of those in common practice today. If current limits for radiation levels at the cask surface and current handling methods are used, high cumulative personnel exposure to ionizing radiation is projected to occur. To reduce these exposure levels, alternate handling methods are being developed and demonstrated. The production nature of cask receiving operations suggests commercial robotics be incorporated into a remote handling system to reduce predicted worker exposure to acceptable levels while maintaining or increasing throughput. The first phase of cask handling system development culminated in a proof-of-principle test demonstrating the feasibility of performing cask receiving and unloading operations in a remote and partially automated manner. ...
Radioactive waste shipping and receiving facilities presently planned for commercial and defense high-level nuclear waste will handle waste packages at frequencies far in excess of those in common practice today. If current limits for radiation levels at the cask surface and current handling methods are used, high cumulative personnel exposure to ionizing radiation is projected to occur. To reduce these exposure levels, alternate handling methods are being developed and demonstrated. The production nature of cask receiving operations, suggests commercial robotics be incorporated into a remote handling system to reduce predicted worker exposure to acceptable levels while maintaining or increasing throughput. The first phase of cask handling system development culminated in a proof-of-principle test demonstrating the feasibility of performing cask receiving and unloading operations in a remote and partially automated manner.
Radioactive waste shipping and receiving facilities presently planned for commercial and defense nuclear waste will handle waste packages at frequencies far in excess of those in common practice today. Unacceptable personnel exposure to ionizing radiation is projected to occur if current limits for radiation levels at the cask surface and current handling methods are used. To reduce these exposure levels, alternate handling methods are being developed and demonstrated. The production nature of cask receiving operations suggests commercial robotics be incorporated into a remote handling system to reduce predicted worker exposure to acceptable levels, while maintaining or increasing throughput. The first phase of cask handling system development culminated in a proof-of-principle test demonstrating the feasibility of performing cask receiving and unloading operations in a remote and partially automated manner. 6 refs., 12 ...
This report covers the second year of the 28 month grant current grant to Clarkson University to study the chemical and physical behavior of the polonium 218 atom immediately following its formation by the alpha decay of radon. Because small changes in size for activity result in large changes in the delivered dose per unit exposure, this behavior must be understood if the exposure to radon progeny and it dose to the cells in the respiratory tract are to be fully assessed. Two areas of radon progeny behavior are being pursued; laboratory studies under controlled conditions to better understand the fundamental physical and chemical process that affect the progeny`s atmospheric behavior and studies in actual indoor environments to develop a better assessment of the exposure of the occupants of that space to the size and concentration of the indoor radioactive aerosol. This report describes the progress toward achieving these ...
This report covers the second year of the 28 month grant current grant to Clarkson University to study the chemical and physical behavior of the polonium 218 atom immediately following its formation by the alpha decay of radon. Because small changes in size for activity result in large changes in the delivered dose per unit exposure, this behavior must be understood if the exposure to radon progeny and it dose to the cells in the respiratory tract are to be fully assessed. Two areas of radon progeny behavior are being pursued; laboratory studies under controlled conditions to better understand the fundamental physical and chemical process that affect the progeny's atmospheric behavior and studies in actual indoor environments to develop a better assessment of the exposure of the occupants of that space to the size and concentration of the indoor radioactive aerosol. This report describes the progress toward ...
The production of retrograde amnesia (RA) upon electron-beam exposure was investigated. RA production was evaluated using a single-trial avoidance task for 10, 1, and 0.1 microsecond pulsed exposures. The dose-response curve obtained at each pulse duration showed significant RA production. The most effective dose range was 0.1-10 rad at a dose rate of 1,000,000 rad/sec. By employing a 10 rad (1,000,000 rad/s) pulse, a memory loss of the events occurring in the previous 4 sec was demonstrated. The conclusion was that the RA effect might be due to sensory system activation which provided a novel stimulus that masked previous stimuli.
The #alpha# radiation dose to the lungs of people who live in buildings constructed of some granites, low density concretes, and gypsum boards is higher than for residents of most other types of dwellings due to the air-borne progeny of radon. There is evidence that sealing the interior surfaces with epoxy paint, for example, can reduce the #alpha# dose to the lung significantly without a compensating increase in whole-body exposure to the #gamma#-rays from radon progeny. Based on the incidence rates for lung cancer in uranium miners, a concentration of radon of the order of 1 to 5 pCi/l. appears to be a reasonable limit for 'lifetime' exposure indoors for 'typical' home ventilation conditions. (author).
In a fluoroscopic imaging system, image quality and patient dose are both affected by the optical system linking the image intensifier with the video camera. The effect on patient exposure of increasing the optical iris aperture size over that required for other procedures performed on the same imaging system was investigated for the air-contrast barium enema examination. Using a large-area transmission ionisation chamber to monitor the Roentgen-area-product of entrance exposure, a decrease in fluoroscopic radiation of greater than 50% was clinically documented for a fluoroscopic system utilising kVp and mA variable automatic brightness control. For this iris change, the video image was of acceptable quality for positioning and monitoring the patient, and no deleterious effect was detected in the conduct of the air-contrast exam. The availability of a variable-sized operator-selectable iris diaphragm would permit this dose-reduction approach to ...
This book gives an overview of the entire field of radiation protection with the subject areas radioactivity, X-rays, UV radiation, laser beams and high-frequency electromagnetic fields. It deals graphically with the most important physical notions, the incidence, origin, properties and biological effects of types of radiation, administrative and practical protection measures and the code of rules governing them. Apart from fundamentals of radiation protection the emphasis on the following: natural radiation exposure, radiation exposure to radon, disaster relief plans in the environment of nuclear plant, the precautionary radiation protection system evolved after Chernobyl, radiation exposure through UV radiation devices, radio, RF communication, radar, microwave ovens and high-voltage transmission lines as well as computer work-places. (orig.).
The effects of repeated low-level nerve agent exposure on animal performance and lethality are a major concern of USAF Medical Research. This concern has generated interest in the role that pretreatment drugs such as pyridostigmine may play during simultaneous exposure to soman. This role was investigated by recording lethality, weights, symptoms, and cholinesterase (ChE) inhibition in rats chronically exposed to 4 levels of soman (32, 39, 48 or 59 micrograms/kg/day) while simultaneously receiving 10.0 milligrams/kg/day pyridostigmine, 1.0 milligrams/kg/day pyridostigmine, or vehicle via an osmotic pump. No effect (either protective or detractive) was found in the soman-poisoned animals due to the presence or absence of pyridostigmine. However, rat blood biochemistry is different from that of the primate, warranting further study in the primate before extrapolation to man.
Coumarin (1,2-benzopyrone) is occurring in food, and is also used in cosmetics. In order to perform a risk assessment for both oral and dermal exposure, we applied a physiologically based approach to model kinetics in humans by simulating both routes of exposure. The concentration-time profile in liver revealed a higher peak concentration (Cmax-hep) for the oral when compared to the dermal route. The area under the concentration-time curve in the liver (AUChep) was found the same for both routes if the same extent of absorption is assumed. Dose response information from published rat studies were used to identify the metric relevant for liver toxicity. Liver exposure levels resulting from doses and durations as outlined in the studies were simulated in a rat model. We obtained 31 data pair...
The winter syndrome in the gilthead sea bream Sparus aurata indicates that the species is exposed to critically low temperatures in Mediterranean aquaculture in winter. The present study of metabolic patterns and molecular stress responses during cold exposure was carried out to investigate this ?disease?, in light of the recent concept of oxygen and capacity limited thermal tolerance. The metabolic profile of fuel oxidation was examined by determining the activities of the enzymes hexokinase (HK), aldolase (Ald), pyruvate kinase (PK), l-lactate dehydrogenase (l-LDH), citrate synthase (CS), malate dehydrogenase (MDH) and 3-hydroxyacyl CoA dehydrogenase (HOAD) in heart, red and white muscle after exposure to temperatures of 10, 14 and 18?C. Especially, the increase in LDH activity combined ...
Carcinogenesis is now generally recognized to be an important detrimental effect in man after low dose irradiation. The carcinogenic action of ionizing radiation is clearly demonstrated after exposure to relatively high doses (in excess of 0.5 Gy) but for lower dose levels reliable direct observations are not available. With the introduction of special protocols for the performance of large scale screening programs by mammography the average absorbed dose in glandular tissue in the average breast can be restricted to a value of 3 mGy per mammogram. The risk for tumor induction after exposure to these low doses can never be established from human epidemiology. In order to investigate the risk of repeated exposure to small dose of ionizing radiation the induction of mammary tumors has been investigated in rats of the WAG/Rij strain after single and fractionated irradiations with gamma-rays. (author). 8 refs., 3 figs.
A.C.R.O. contests some new recommendations of ICRP: a scale based on the ambient natural exposure ( 'it is not dangerous because it is the natural level'), a level of exposure called trivial risk with the threshold value at 30 {mu}Sv. Even if the value is proposed now at 10 {mu}Sv, it is the notion of threshold that is contested. For A.C.R.O. These new considerations would lead to significant exposure levels, tend to the everyday acceptance of the risk, aim at exempting of their responsibilities the nuclear operators, the politics and the institutions which urge upon the development of large nuclear programs without trying beforehand to ponder all the consequences in particular on the long term. (N.C.)
Extensive epidemiological studies have been carried out in recent years to examine the possible effects of exposure to extremely low frequency electromagnetic fields on the development of cancer. In some studies, both residential and occupational, a number of cancers, in particular leukaemia and brain cancer, have occurred at an increased incidence at higher levels of exposure. In general, however, no consistent and coherent pattern of results has been obtained and no clear evidence of a cancer risk has been demonstrated. A better understanding of any effect of electromagnetic fields on the development of cancer must await the results of more informative epidemiological studies and an improved understanding of the mechanisms by which these fields may interact with the body and their likely consequences. (author)
The relative risk model (RRM) was applied in regional ecological risk assessments successfully. In this study, the RRM was developed through increasing the data of risk source and introducing the source?stressor?habitat exposure filter (SSH), the endpoint?habitat exposure filter (EH) and the stressor?endpoint effect filter (SE) to reflect the meaning of exposure and effect more explicit. Water environment which include water quality, water quantity and aquatic ecosystems was selected as the ecological risk assessment endpoints. The Luanhe River Basin located in the North China was selected as model case. The results showed that there were three low risk regions, one medium risk region and two high risk regions in the Luanhe River Basin. The results also indicated habitat destruction was th...
Evaluations were done to determine conditions that could permit nuclear criticality with fissile uranium in low-level waste (LLW) facilities and to estimate potential radiation exposures to personnel if there were such an accident. Simultaneous hydrogeochemical and nuclear criticality studies were done (1) to identity realistic scenarios for uranium migration and concentration increase at LLW disposal facilities, (2) to model groundwater transport of uranium and subsequent concentration via sorption or precipitation, (3) to evaluate the potential for nuclear criticality resulting from potential increases in uranium concentration over disposal limits, and (4) to estimate potential radiation exposures to personnel resulting from criticality consequences. This paper presents the details of the radiation exposure calculations relying on the conditions as determined from the preceding studies detailed in a cited reference.
Humans are exposed to chemicals in contaminated groundwaters that are used as sources of drinking water. Chemicals contaminate groundwater resources as a result of waste disposal methods for toxic chemicals, overuse of agricultural chemicals, and leakage of chemicals into the subsurface from buried tanks used to hold fluid chemicals and fuels. In the process, both the solid portions of the subsurface and the groundwaters that flow through these porous structures have become contaminated. Restoring these aquifers and minimizing human exposure to the parent chemicals and their degradation products will require the identification of suitable biomarkers of human exposure; better understandings of how exposure can be related to disease outcome; better understandings of mechanisms of transport of pollutants in the heterogeneous structures of the subsurface; and field testing and evaluation of methods proposed to restore and ...
Simultaneous exposures of rats and hamsters to inhaled radon daughters, with and without uranium ore dust, were performed daily for five months. Pulmonary pathology developing in 6 to 13 mo after cessation of daily exposures included interstitial fibrosis, emphysema, epithelial hyperplasia, squamous metaplasia, and malignant neoplasia. Rats showed a greater variety and more severe response to these uranium mine inhalation exposures than did hamsters. Inhalation of radon daughters with uranium ore dust displayed the site of greatest damage, including squamous carcinoma, from the nasopharynx to the lungs. Sixty percent of the rats exposed to radon daughters with ore dust developed primary pulmonary carcinomas, providing an appropriate short-term experimental animal model for investigation of respiratory tract carcinogenesis in uranium miners.
Application of the Geographic Information System (GIS) with a statistical model to evaluate the magnetic field exposure of a population from high-voltage transmission lines near residential areas is discussed, focusing on the interaction of the GIS with the statistical model. In an effort to validate the model measurements of the magnetic field, profiles were taken at two sites and these profiles have been compared with calculated values. Two conclusions have been drawn from the results: (1) the statistical model linked with the GIS is a very powerful tool for the evaluation of exposure of a population to magnetic fields, and (2) success depends on the presence of other sources of magnetic fields and on the exactness of the data used in the model. 4 refs., 5 figs.
The properties of a new commercial thermoluminescent dosimeter, CaSO4:Dy without a LiF binder (TLD-900) was studied for low-exposure measurements in diagnostic radiology. The former TLD-900 had a LiF binder (herein referred to as ''TLD-900/LiF''). The principle features of this dosimeter are its high sensitivity to low-energy radiation and its relatively low fading which permits measurements down to less than 2.6 X 10(-8) C kg (0.1 mR) with an accuracy better than 20%. The characteristics, annealing procedures, light sensitivity, energy response, reproducibility, and fading, of TLD-900 are discussed and compared with TLD-900/LiF. When the precautions presented in this paper are used, the dosimeters can be used for the measurement of x-ray exposures.
ObjectivesThe development of novel formulations of nanoparticles in the nanotechnology industry and their increasing importance and use in industry means there is certainty of human environmental exposures in both the workplace and the general environment. The pulmonary route of exposure to airborne nanoparticles is a major one, as nanoparticles are handled in industry, escape from workplaces and products containing nanoparticles undergo attrition in the environment. There is a substantial problem for ris [continued...]DescriptionNanoparticles are extremely small particles, each individual particlel being less than one ten millionth of a metre in size. We are exposed to nanoparticles in busy streets as they are present in traffic exhaust produced from combustion of fuel and such nanoparticles are considered to be important in causing the harmful effects associated with exposure to air pollution. There are other situations ...
During the first and second quarters of 1994 air samples were collected and analyzed from 54 air particulate/halogen sampling stations, 10 noble gas sampling stations and 19 tritiated water vapor sampling stations. Surface water samples were collected and analyzed from 12 open water supply reservoirs, 8 natural springs, 2 wastewater containment ponds and 9 sewage lagoons. Groundwater samples were obtained brom 10 potable and 1 non-potable supply wells, and 8 drinking water consumption points. Ambient radiation levels were measured at 193 locations.
Differential Scanning Calorimetry (DSC) is employed to study the changes in enthalpy of natural rubber latex samples when heated under a controlled temperature program. It is found that the mass normalized areas of the DSC curves between room temperature and 170??C for different latex samples are inversely proportional to the dry rubber content (DRC) of the samples, measured following the weighing and drying method. The changes in total enthalpy of the samples in this temperature range are interpreted as due to the variations in the quantity of water present in the samples. The measurements have been repeated by diluting selected samples with known quantities of water, and it is found that the normalized areas of the DSC curves are directly proportional to the amount of water added to the ...
This paper presents the development of technical requirements for the design of aircraft-mounted sampling equipment for the airborne radioactivity monitoring. A design concept and internal equipments required for the sampling system will be described in detail to provide information for the development of technical requirements for aircraft-mounted sampling equipment. This will be followed by description of the exterior designing process. Difficulties of designing exterior of the sampling system lie in the fluid dynamics performance of the system. The objective of the design is to maximize the suction flow necessary for achieving high efficiency of radionuclide sampling, while minimizing disturbance to the aircraft which carries the system. The design optimization was performed with the computational fluid dynamics (CFD) code FLUENT. The design options considered here were (1) ...
SummaryBackground The choice of sampling techniques in bronchoscopy with sampling from a visible lesion will depend on the expected diagnostic yields and the costs of the sampling techniques. Aims The aim of this study was to determine the most economical combination of sampling techniques when approaching endobronchial visible lesions. Methods A cost minimization analysis was performed. All bronchoscopies from 2003 and 2004 at Haukeland university hospital, Bergen, Norway, were reviewed retrospectively for diagnostic yields. 162 patients with endobronchial disease were included. Potential sampling techniques used were biopsy, brushing, endobronchial needle aspiration (EBNA) and washings. Costs were estimated based on registration of equipment costs and personnel costs. Sensitivity analyse...
An easy and simple method for gamma assay of large multi-gamma lines samples was introduced in this work. This method performs the assay using point source calibration. The correction factors for volume and self-attenuation are experimentally deduced from the spectra of different thicknesses samples utilizing the following two simple well known facts: large and small samples of the same homogenous material have identical specific activities; the self-attenuation of gamma line decreases as its energy increases. The method was successfully applied to naturally occurring radioactive material (NORM) large samples. This method does not require complicated mathematical procedures. Neither sample matrix data nor detector unit composition is needed.
An easy and simple method for gamma assay of large multi-gamma lines samples was introduced in this work. This method performs the assay using point source calibration. The correction factors for volume and self-attenuation are experimentally deduced from the spectra of different thicknesses samples utilizing the following two simple well known facts: large and small samples of the same homogenous material have identical specific activities; the self-attenuation of gamma line decreases as its energy increases. The method was successfully applied to naturally occurring radioactive material (NORM) large samples. This method does not require complicated mathematical procedures. Neither sample matrix data nor detector unit composition is needed.
An easy and simple method for gamma assay of large multi gamma lines samples was introduced in this work. This method performs the assay using point source calibration. The correction factors for volume and self-attenuation are experimentally deduced from the spectra of different thicknesses samples utilizing the following tow simple well known facts: Large and small samples of the same homogenous material have identical activities; the self attenuation of gamma line decreases as its energy increases. The method was successfully applied to NORM (Naturally Occurring Radioactive Material) large samples. This method doesn't require complicated mathematical procedures. Neither sample matrix data nor detector unit composition is needed. (author)
This paperwork explain the method of water sampling to obtain the precipitate of BaCO3 solutions that will be used to analyze 13C from field work in Kelana Jaya, Selangor, Langkawi, Kedah and Taiping, Perak. The sampling involves collecting of water samples for groundwater from boreholes and surface water from canal, river, pond and ex-mining pond from several locations at the study sites. This study also elaborates the instruments and chemicals used. The main purpose of this sampling is to obtain the precipitate of BaCO3 for 13C analysis of dissolved inorganic carbon (DIC). A correct sampling method according to standard is very important to ensure an accurate and precise result. With this, the data from the laboratory analysis result can be fully utilized to make the interpretation of the pollutants movement. (Author)
This paper summarizes the deliberations of a work group charged with addressing specific questions relevant to risk estimation in developmental neurotoxicology. We focused on eight questions. a) Does...Full Text Available
Power system analysis shows the output from the solar arrays varies as a function .... Each array corresponds to a raw image browse product, which is generated by .... low outgassing, ability to withstand long-term exposure to the space ...
Geographic information systems (GIS) are being used with increasing frequency in environmental epidemiology studies. Reported applications include locating the study population by geocoding addresses...Full Text Available
BackgroundSelection programs for growth and stress traits in cultured fish are fundamental to the improvement of aquaculture production. The gilthead sea bream (Sparus aurata)...Full Text Available
As part of a U.S. multi-regional pilot study conducted by the six Centers for Radiological Physics, 12-mm-diameter by 0.4-mm-thick CaSO/sub 4/:Dy Teflon-embedded discs were evaluated and used to measure patient entrance exposure on 60 average patients at 12 clinical centers. The discs were found to have adequate sensitivity, reproducibility and linearity up to 69.7 microC kg-1 (270 mR). The minimum measurable exposure was estimated as 0.4 microC kg-1 (1.5 mR). All responses were corrected for energy dependence, which varied +/- 20% from 1.7 to 6.5 mm Al half-value layer. Patient entrance exposure values ranged from 1.3 to 28 microC kg-1 (5 to 110 mR), with a median value of 5.2 microC kg-1 (20 mR). This value agreed with exposure measurements made on the chest radiography equipment using an ionization chamber and a phantom which simulated an average patient, and with published Nationwide Evaluation of ...
Depleted uranium (DU) is a dense heavy metal used primarily in military applications. Although the health effects of occupational uranium exposure are well known, limited data exist regarding the long-term...Full Text Available
Anesthetized rats were exposed to 5.6-GHz continuous-wave radiofrequency radiation (RFR) at an average power density of 60 mW/Sq. cm (average specific absorption rate 12 W/kg). Exposure was performed to raise colonic temperature from 38.5 to 39.5C. Following acute administration of chlorpromazine, body temperature exhibited a faster return to baseline temperature when exposure was discontinued. When exposure was initiated at 38.5C and continued until lethal temperature resulted, chlorpromazine-treated animals exhibited significantly shorter survival times than saline-treated animals. Thus, although chlorpromazine enhanced thermoregulatory efficiency at colonic temperature below 39.5 deg C, the drug caused increased susceptibility to terminal RFR. The present results, when compared with previous studies of irradiation at 2.8 GHz, indicate that the effects of chlorpromazine on thermal response to RFR during intermittent and ...
Human exposure to perchlorate is commonplace because it is a contaminant of drinking water, certain foods, and breast milk. The U.S. Environmental Protection Agency (EPA) conducted a perchlorate risk...Full Text Available
Background Microbial water-quality indicators, in high concentrations in sewage, are used to determine whether water is safe for recreational purposes. Recently, the use of these indicators...Full Text Available
Intraindividual variability of measurements of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), nicotine, cotinine, and r-1,t-2,3,c-4-tetrahydroxy-1,2,3,4-tetrahydrophenanthrene...Full Text Available
Microplanar beam radiation therapy has been proposed to treat brain tumors by using a series of rapid exposures to an array of parallel x-ray beams, each beam having uniform microscopic thickness and...Full Text Available
Possible health risks associated with occupational inhalation of mycotoxin-containing dust remain largely unknown, partly because methods for mycotoxin detection are not sensitive enough for the small...Full Text Available
According to world statistics, dogs and cats are the species that owners most frequently seek assistance with potential poisonings, accounting 95–98% of all reported animal cases. Exposures...Full Text Available
Exposure of albumin to Cu(II) (10-100 microM) and ascorbate (0.1-2 mM) results in extensive molecular modifications, indicated by decreased fluorescence and chain breaks. The rate of utilization of...Full Text Available
A single exposure energy subtraction technique with a metal filter and an imaging plate for the Fuji Computed Radiography (FCR) system was developed for dual-energy subtraction radiography (DES) of the chest. By the use of this technique, 206 patients with suspected lung cancer were scanned in the clinical settings. The subtracted images in 200 patients, excluding six with poor image quality, were examined. Soft-tissue images (bone cancelled images) were useful in visualizing abnormality of the airway and nodules lying under the ribs; and bone images (soft-tissue cancelled images) in detecting rib metastases and the presence or absence of calcification in nodules. Additional information was acquired in 21 % (42/200). A single exposure is capable of neglecting motion artifacts. In addition, this technique may be of value in DES, which is considered to be one of the routine examinations, in view of low exposure doses. The ...
A single exposure energy subtraction technique with a metal filter and an imaging plate for the Fuji Computed Radiography (FCR) system was developed for dual-energy subtraction radiography (DES) of the chest. By the use of this technique, 206 patients with suspected lung cancer were scanned in the clinical settings. The subtracted images in 200 patients, excluding six with poor image quality, were examined. Soft-tissue images (bone cancelled images) were useful in visualizing abnormality of the airway and nodules lying under the ribs; and bone images (soft-tissue cancelled images) in detecting rib metastases and the presence or absence of calcification in nodules. Additional information was acquired in 21 % (42/200). A single exposure is capable of neglecting motion artifacts. In addition, this technique may be of value in DES, which is considered to be one of the routine examinations, in view of low exposure doses. The ...
Chemicals having a capacity to disturb the endocrine system have attracted considerable interest during recent years. There is a shortage of well-characterized in vivo tests with which to study such...Full Text Available
BackgroundPolychlorinated biphenyls (PCBs) may cause immunotoxic effects, but the detailed dose–response relationship and possible vulnerable time windows of exposure are...Full Text Available
Two men reported previously with vitiligo after occupational exposure to hydroquinone monomethyl ether (HMME) have been reviewed after eight years. Repigmentation of significant degree was found in...Full Text Available
OBJECTIVES: To reassess the risk of leukaemia associated with residential exposure near high voltage transmission electric lines of 49 kV and above in view of the recent publications. METHODS: Through...Full Text Available
The phagocytic and killing abilities of heifer mammary gland macrophages (M phi) and neutrophils were evaluated after exposure to recombinant bovine interferon-gamma (rBoIFN-gamma) stimulation in vitro....Full Text Available
Pattern and model makers are skilled tradespersons who may be exposed to hardwoods, softwoods, phenol-formaldehyde resin-impregnated woods, epoxy and polyester/styrene resin systems, and welding and metal-casting fumes. The relationship of respiratory symptoms (wheezing, chronic bronchitis, dyspnea) and pulmonary function (FVC% predicted, FEV1% predicted, FEV1/FVC% predicted) with interview-derived cumulative exposure estimates to specific workplace agents and to all work with wood, plastic, or metal products was investigated in 751 pattern and model makers in southeast Michigan. In stratified analyses and age- and smoking-adjusted linear and logistic regression models, measures of cumulative wood exposures were associated with decrements in pulmonary function and dyspnea, but not with other symptoms. In similar analyses, measures of cumulative plastic exposures were associated with wheezing, chronic bronchitis, and ...
Lifetime exposure to physical activity is an important construct for evaluating associations between physical activity and disease outcomes, given the long induction periods in many chronic diseases....Full Text Available
The relationship between malaria transmission intensity and clinical disease is important for predicting the outcome of control measures that reduce transmission. Comparisons of hospital data...Full Text Available
The prevalence of obesity among children, adolescents and adults has been dramatically increasing worldwide during the last several decades. The obesity epidemic has been recognized as one of...Full Text Available
Gene expression is a unique way of characterizing how cells and organisms adapt to changes in the external environment. The measurements of gene expression levels upon exposure to a chemical can be...Full Text Available
We report the radiation exposure dose received by the anesthesiologist and nurse in the orthopaedic operating room, when a fluoroscopic image intensifier is in use. This study was done in 12 femoral neck fracture operations performed from January to May 1995. Radiation was monitored with the MYDOSE MINIX PDM 107 made by Aloka Co. which were attached in front and behind the nurse's lead apron, in front of the lead apron of the anesthesiologist. The average imaging time was 9.78 min. The average radiation dose in front of the anesthesiologist is lead apron was 2.08#mu#SV, and in front and behind the nurse's lead apron were 5.67#mu#SV, 0.08#mu#SV respectively. This study and review of the literature indicate that the operating room anesthesiologist and nurse receive a lower exposure than the orthopaedist. We can disregard the problem of radiation exposure to the anesthesiologist and nurse during an orthopaedic operation when ...
Exact anatomic knowledge about the location of the gonads and the application of corresponding measures of radiation protection are the preconditions for an efficient reduction of the danger of a possible genetic damage as a result of radiation exposition during X-ray examination of the hip joint of newborns. (VJ).
Trichloroethylene (TCE) is both acutely toxic and carcinogenic to the mouse lung following exposure by inhalation. In contrast, it is not carcinogenic in the rat lung and is markedly less toxic following...Full Text Available
Hypoxia, or reduced oxygen, occurs in a variety of clinical and environmental situations. Hypoxic exposure is associated with decreased muscle mass and a concomitant reduction in exercise capacity,...Full Text Available
Prenatal cocaine exposure produces sustained neurobehavioral and brain synaptic changes closely resembling those of animals with defective alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic...Full Text Available
School buses contribute substantially to childhood air pollution exposures yet they are rarely quantified in epidemiology studies. This paper characterizes fine particulate matter (PM2.5)...Full Text Available
Brief exposures to red light induce far red-reversible changes of 5 to 10 millivolts magnitude in the upper 1 centimeter of etiolated Avena coleoptiles. The changes begin within 15...Full Text Available
The phytochrome-mediated attachment of root tips of mung bean (Phaseolus aureus) and barley (Hordeum vulgare) to glass is affected by the prior exposure of hydrated...Full Text Available
1. Radioactive products in detached leaf segments were examined after periods of steady-state photosynthesis in 14CO2. 2. After exposure to 14CO2 for approx....Full Text Available
The ability of bovine polymorphonuclear leukocytes (PMN) to phagocytose fluorescent beads in vitro was studied using flow cytometry. The effects of varying laboratory conditions (bead:PMN ratio, length...Full Text Available
Benzidine (4,4'-diaminobiphenyl) is a known human carcinogen; exposure to this substance resulted in an epidemic of bladder cancer among workers in the dye industry in Europe and North America. The...Full Text Available
Exposure of a group of horses to tetracycline-contaminated feed resulted in acute colitis and subsequent death in one horse and milder diarrhea in 3 others. The most severely affected animal demonstrated...Full Text Available
Importance of the fieldThe cytochrome P450 (CYP) isoforms that are selectively induced following exposure to structurally-diverse chemicals often are the ones capable...Full Text Available
IntroductionWhile epidemiological methods have grown in sophistication during the 20th century, their application in historical occupational (and environmental) health...Full Text Available
BackgroundThe long-term neurotoxicity risks caused by prenatal exposures to pesticides are unclear, but a previous pilot study of Ecuadorian school children suggested that blood...Full Text Available
The possible contribution to urinary mutagenicity of occupational exposures in the rubber industry was studied by assaying the urine concentrates of 72 workmen (44 smokers) employed in a tyre plant....Full Text Available
The studies reported here used genetic differences in susceptibility of C57BL/6N and C3H/HeN mice and exacerbation of the disease by nitrogen dioxide (NO/sub 2/) as tools in assessing the role of early host responses in the pathogenesis of MRM. The two strains did not differ in susceptibility to infection, but C3H/HeN mice were more susceptible to and had increased severity of lung lesions 14 days after intranasal inoculation as determined by 50% biological endpoints and morphometric analysis of tissues. Exposure to NO/sub 2/ for 4 hours prior to exposure to infectious aerosols exacerbated murine respiratory mycoplasmosis (MRM) by 7 days after exposure in both mouse strains. NO/sub 2/ appeared to affect host lung defense mechanisms responsible for limiting mycoplasmal growth in the lungs. The NO/sub 2/ exposure concentration required for this effect varied with the genetic background of the host, the ...
Several studies have raised the possibility that exposure to electrical and/or magnetic fields may be injurious to health in particular by the promotion or initiation of cancer. To investigate whether...Full Text Available
This report examines the mortality experience of 527 men who retired from a copper smelter where they were exposed to airborne arsenic trioxide. Urinary arsenic values of all plant employees were determined...Full Text Available
Mitochondrial heat shock protein 70 (mtHSP70) is found to play a primary role in cellular defense against physiological stress like exposure to environmental contaminants and helpful in the maintenance...Full Text Available
The goal of this study was to determine if the exaggerated morphine-induced conditioned place preference (CPP) response seen in adult rats after preweanling methylphenidate exposure is unique...Full Text Available
Amorphous silicon solar cells have been shown to have efficiencies which degrade as a result of long exposure to light. Annealing such cells in air at a temperature of about 200.degree. C. for at least 30 minutes restores their efficiency.
The exposure of cells to several metal ions stabilizes HIF-1α protein. However, the molecular mechanisms are not completely understood. They may involve inhibition of hydroxylation by either...Full Text Available
BackgroundTwo planned trials of pre-exposure prophylaxis tenofovir in Cambodia and Cameroon to prevent HIV infection in high-risk populations were closed due to activist pressure...Full Text Available
Gestational exposure to maternal overweight (OW) influences the risk of obesity in adult life. Male offspring from OW dams gain greater body weight and fat mass and develop insulin resistance when fed...Full Text Available
... hepatopancreas (1.55 ppm), gonad (5.18 ppm), epithelial tissue (6.17 ppm) and, most significantly, the eyestalks ( ... by Day 1 Stage I larvae and by epithelial tissue of postmolt juvenile lobsters. Postmo...
BackgroundIn a previous study conducted at the Cesare Maltoni Cancer Research Center of the European Ramazzini Foundation (CMCRC/ERF), we demonstrated for the first time that aspartame...Full Text Available
This study examines some radiation accidents occurred in the past. This information has been systematically assessed to get global lessons. The experience feedback shows that the most of accidents happened in certain conditions. These conditions can be distributed in four categories: 1- perception and vigilance in occupation: accidental exposure happened by lack of vigilance in details and lack of vigilance and perception; 2- procedures: accidental exposure happened following a lack of procedures or control that were not enough complete, not enough documented or not completely implemented; 3- training and understanding: accidental exposures happened because the personnel was not enough qualified and educated, did not get the general training nor the the necessary specialized training; 4- liabilities: accidental exposures happened following lacks and ambiguity in the definition of functions of the ...
An ex-employee's claims that inadequate enforcement of radiation safety regulations allowed excess radiation exposure thereby causing his deteriorating health was not substantiated by a thorough investigation.
Simultaneous or prior exposure to one chemical may alter the concurrent or subsequent response to another chemical, often in unexpected ways. This is particularly true when the two chemicals...Full Text Available
Exposure of mice to 1000 ppm of vinyl chloride (VC), 6 hr/day, 5 days/week, caused some acute deaths with toxic hepatitis and marked tubular necrosis of the renal cortex. Starting the sixth month,...Full Text Available
OBJECTIVE--To assess whether occupational exposure among commercial airline cabin attendants are associated with risk of cancer. DESIGN--Record linkage study. SETTING--Finland. SUBJECTS-1577 female...Full Text Available
Exposure of animals to hyperoxia decreases lung VEGF mRNA expression concomitant with an acute increase in VEGF protein within the epithelial lining fluid (ELF). The VEGF concentration in ELF...Full Text Available
Data from exposure of experimental animals and human subjects to sulfuric acid presents a consistent picture of its toxicology. Effects on airway resistance in asthmatic subjects were well predicted...Full Text Available
Air pollution measurements were conducted over a 1-year period in 24 North American communities participating in a respiratory health study. Ozone, particle strong acidity, sulfate, and mass (PM10 and...Full Text Available
May 10, 2009 ... The estimated magnitude is 18.95 with a 1-sigma error of about 0.17. ... The points of contact for this burst is Masanori Ohno .... 80 seconds after the BAT trigger with a settling exposure in the UVOT v filter. ...
The authors studied noncancer mortality among phenoxyacid herbicide and chlorophenol production workers and sprayers included in an international study comprising 36 cohorts from 12 countries followed...Full Text Available
BackgroundEarly exposure to ovarian hormones is considered to increase breast cancer incidence. The age at which the ovaries become functional is thus important.Full Text Available
Recommended ERLs for whole body, thyroid, lung and other single organs are presented in tabular form, and related to the relevant counter measures such as evacuation, sheltering, distribution of stable iodine tablets, etc. Application of ERLs to local env...
An assessment has been made of biochemical alterations in renal and hepatic functions of 73 male operators employed for an average of 8.2 years (range 0.5-23 years) in a chemical plant producing chlorinated...Full Text Available
Nineteen-day-old dwarf sunflower plants (Helianthus annuus, variety NK894) received a variable dose (0-40 Gy) from a cobalt-60 gamma source. A very sensitive stem monitoring device, developed at Battelle's Pacific Northwest Laboratories, Richland, Washington was used to measure real-time changes in stem diameter. Exposure of plants caused a significant reduction in stem growth and root biomass. Doses as low as 5 Gy resulted in a significant increase in leaf density, suggesting that nonreversible morphological growth changes could be induced by very low doses of radiation. Carbohydrate analysis of 40-Gy irradiated plants demonstrated significantly more starch content in leaves and significantly less starch content in stems 18 days after exposure than did control plants. In contrast, the carbohydrate content in roots of 40-Gy irradiated plants were not significantly different from unirradiated plants 18 days after ...
The purpose of the present study was to determine whether exposure to exogenous physiological concentrations of caffeine influence contractility, Ca2+ handling, and fatigue development...Full Text Available
Nursing infants may be exposed to lead from breast milk, but relatively few data exist with which to evaluate and quantify this relationship. This route of exposure constitutes a potential infant hazard...Full Text Available
Dogs are domestic reservoir hosts of Trypanosoma cruzi, the etiological agent of Chagas disease. We evaluated the effect of deltamethrin-treated dog collars (DTDCs) over time...Full Text Available
Exposure of Mycobacterium tuberculosis to hypoxia is known to alter the expression of many genes, including ones thought to be involved in latency, via the transcription factor DevR...Full Text Available
Although skin is usually exposed during human exposures to ionizing radiation, there have been no thorough examinations of the transcriptional response of skin fibroblasts and keratinocytes...Full Text Available
The risk of lung cancer associated with diesel exhaust has been calculated from 14 case-control or cohort studies. We evaluated the findings from these studies to determine whether there is sufficient evidence to implicate diesel exhaust as a human lung carcinogen. Four studies found increased risks associated with long-term exposure, although two of the four studies were based on the same cohort of railroad workers. Six studies were inconclusive due to missing information on smoking habits, internal inconsistencies, or inadequate characterization of diesel exposure. Four studies found no statistically significant association. It can be concluded that short-term exposure to diesel engine exhaust (20 years) increases the risk of lung cancer for locomotive engineers, brakemen, and diesel engine mechanics. There is inconsistent evidence on the effects of long-term exposure to diesel exhaust in the trucking ...
At Wolsung NPP, three more CANDU reactors will be operated soon, and the tritium accumulation in the moderator and coolant systems was estimated to be greatly increased. In order to reduce tritium exposure for nuclear safety at Wolsung, a study was carrie...
BackgroundChronic wasting disease (CWD) of cervids is a prion disease distinguished by high levels of transmissibility, wherein bodily fluids and excretions are thought to play an...Full Text Available
A new method is being developed to quickly screen for the human exposure potential to polycyclic aromatic hydrocarbons (PAHs) and organochlorines (OCs). The development involves two key elements: identifying suitable signals that represent intracellular changes that are specific to PAH and OC exposure, and constructing a device to guide the biological cell growth so that signals from individual cells are consistent and reproducible. We are completing the identification of suitable signals by using synchrotron radiation-based (SR) Fourier-transform infrared (FTIR) spectromicroscopy in the mid-infrared region (4000-400 cm-1). Distinct changes have been observed in the IR spectra after treatment of human cells in culture medium with PAHs and OCs. The potential use of this method for detecting exposure to PAHs and OCs has been tested and compared to a reverse transcription polymerase chain reaction (RT-PCR) assay that ...
Exposure control at the operating Nuclear Power Station is a major concern. TAPS Unit-4 is the first Pressurized Heavy Water Reactor of 540 MWe electrical capacity. This unit was made critical on March 6, 2005. In-depth review of radiation safety was done to identify the impact of design modification on dose rates at various locations and on the equipment's. Problems encountered in controlling the dose rates in 220 MWe electrical are eliminated by appropriate design modifications. Due to higher capacity of the unit there are design changes in major systems such as reactor core, primer heat transport system, moderator system, reactor regulation and protection systems. Reactor operations and maintenance activities during shut down contributes to exposure of the employees. Based on the experience gained in the operation of 220 MWe, design modifications incorporated in TAPS unit-4 and dose rate measurements carried out at 90 % full power, through ...
The causality of observed associations between air pollution and respiratory health in children is still subject to debate. If reduced air pollution exposure resulted in improved respiratory health...Full Text Available
In case of operating both Wolsung Nuclear Units 1 and 2 without operating tritium removal facilities, it is estimated that tritium in 2013 would be accumulated up to about 30 million Ci that would result in about 2,300 man-rem of tritium exposure to opera...
Rhesus monkeys were infected with strains of Schistosoma mansoni from Puerto Rico, St Lucia, Brazil, and Tanzania. Monkeys were killed 11-14 weeks after exposure to 600-650 cercariae....Full Text Available
The clinical signs and postmortem findings in sheep from two flocks accidentally poisoned with monensin are described. Clinical signs began within 24 hours of exposure to monensin. In the acute stages...Full Text Available
The effect of potential risk factors for chronic lymphatic leukaemia was evaluated in a case-referent study encompassing 111 cases and 431 randomised referents, all alive. Information on exposure was...Full Text Available
Acetylcholine and other neurotransmitters play unique trophic roles in brain development. Accordingly, drugs and environmental toxicants that promote or interfere with neurotransmitter function evoke neurodevelopmental abnormalities by disrupting the timing or intensity of neurotrophic actions. The current review discusses three exposure scenarios involving acetylcholine systems: nicotine from maternal smoking during pregnancy, exposure to environmental tobacco smoke (ETS), and exposure to the organophosphate insecticide, chlorpyrifos (CPF). All three have long-term, adverse effects on specific processes involved in brain cell replication and differentiation, synaptic development and function, and ultimately behavioral performance. Many of these effects can be traced to the sequence of cellular events surrounding the trophic role of acetylcholine acting on its specific cellular receptors and associated signaling cascades. ...
Calcium, vitamin D, exposure to sunshine, and vitamin D receptor (VDR) genotypes have been associated rectal cancer. We used data from 750 rectal tumors and 1,205 population-based...Full Text Available
BackgroundEvidence on human semen quality as it relates to exposure to various metals, both essential (e.g., zinc, copper) and nonessential (e.g., cadmium, lead), is inconsistent....Full Text Available
This table contains point-source catalogs for the ~2 Ms exposure of the Chandra Deep ... Source positions are determined using centroid and matched-filter techniques; .... The 1-sigma upper statistical error (Gehrels 1986, ApJ, 303, ...
Transmission electron microscopy analysis (TEMA) was used to analyze the bronchoalveolar lavage fluid (BALF) of 262 subjects occupationally exposed (OE) to nonfibrous mineral particles (NFMP) and 42...Full Text Available
Current pesticide health risk assessments in the United States require the characterization of aggregate exposure and cumulative risk in the setting of food tolerances. Biologic monitoring can aggregate...Full Text Available
Heat production in biological materials due to absorption of radiowaves and microwaves can be used in applications as diverse as cancer treatment and cooking. However, the hazards of overexposure range from hyperthermia to cataracts and internal burns. To maximize the clinical benefits and minimize potential hazards, the biological effects of radiowaves and microwaves must be understood. Dielectric measurements can be used to determine the extent of such effects in various applications and at various levels of exposure. The values of maximum permissible exposure levels that are likely to be recommended aeat production in biological materials due to absorption of radiowaves and microwaves can be used in applications as diverse as cancer treatment and cooking. However, the hazards of overexposure range from hyperthermia to cataracts and internal burns. To maximize the clinical benefits and minimize potential hazards, the biological effects of ...
BackgroundHealth risk from exposure of perfluorochemicals (PFCs) to wildlife and human has been a subject of great interest for understanding their molecular mechanism of toxicity....Full Text Available
...2 Resource type: documents Mesothelioma Information HON-code certified resource, covering the main aspects of asbestos exposure: diagnosis, diseases caused by asbestos, treatment options, prevention and legal options. Diagrams are included in articles, and links are provided to the references used. Also contains a listing of ...
BackgroundPrevious research has demonstrated that exposure to images depicting the thin female ideal has negative effects on some females' levels of body dissatisfaction. Much of...Full Text Available
OBJECTIVES—To investigate the relation between different types of exposure to noise and a classic sign of noise induced hearing loss (NIHL), the audiometric notch. METHODS—The...Full Text Available
BackgroundArsenic (As) exposure during pregnancy induces oxidative stress and increases the risk of fetal loss and low birth weight.ObjectivesIn...Full Text Available
The different radiation loads caused by natural and artificial radionuclides are compared in this paper. This examples will serve to illustrate that the problem of population exposure to radiation can only be solved in consideration of all components and to show which effects of the radiation from natural sources are of special importance in this connexion. (orig./AK).
A case study is presented where an integrated, ecologically relevant exposure assessment is presented for a polluted lowland river. Using partial least squares regression of latent structures (PLS), an analysis of the impact of two effluents on physico-chemical water quality measures, macroinvertebrate and diatom communities, and in situ bioassay responses with four different test species are combined into an integrative exposure assessment. Bioassays focussed on growth and condition related endpoints, because they are key functional processes of organisms and populations. Integrating these multiple lines of evidence, we were able to discriminate among the impact of both effluents, link changes in physico-chemical water quality with bioassay endpoints and ecological quality of the ecosystem, and address the importance of integrating all information into one exposure assessment framework. The bioassays under field conditions ...
Abs are central to malaria immunity, which is only acquired after years of exposure to Plasmodium falciparum (Pf). Despite the enormous worldwide burden of malaria,...Full Text Available
An exposure chamber is described for the quantifiable addition of fine and ultrafine aerosol particulate matter directly to cells and used to demonstrate the in vitro cytotoxicity of fine 1,4-naphthoquinone particles to murine lung epithelial cells. The electrostatic particulate dosage and exposure system (EPDExS) operates on the principle of electrostatic precipitation and is shown to deposit fine and ultrafine aerosol particles directly to cells with 100% efficiency for particle diameters in the range of 40-530nm. This range is not limited by the EPDExS, but rather by the aerosolization method used for this study. Numbers of particles deposited onto the cells are counted with a condensation particle counter, negating any need to calculate or estimate particle exposure. The process of particle introduction, assessed using Trypan blue dye exclusion, had no effect on cell viability. In combination with a differential ...
Water-maze testing has been used to assess prenatal cocaine (PCOC)- induced deficits in behavioral studies of spatial navigation and memory abilities. Effects of PCOC in acquisition or in probe...Full Text Available
Hypersensitivity pneumonitis (HP) is an inflammatory lung disease caused by repeated inhalation of aerosolized antigens. With chronic exposure to an inhaled antigen, patients are at risk of...Full Text Available
There is increasing concern for the potential adverse health effects of human exposures to chemical mixtures. To better understand the complex interactions of chemicals within a mixture, it is essential...Full Text Available
Surface doses received by patients and operators were measured during 30 interventional radiological procedures (ten percutaneous transhepatic biliary drainages, ten percutaneous nephrostomies, ten percutaneous transluminal angioplasties). In addition, organ doses to the patient were determined using an Alderson-Rando phantom. These served as a basis for calculating the so-called somatic dose indices. It was found that the somatic radiation risk to the patient is relatively small despite prolonged periods of fluoroscopy. However, exposure of the hands and lenses of the operator could easily reach the limits thought acceptable while carrying out these procedures with additional angiography. (orig).
The genetically and leukemia-significant doses (GSD and LSD) were calculated from the average gonad and bone marrow doses caused by the most frequently applied radiopharmaceuticals in Bulgaria in 1976. Because of the lack of information about the age groups of the patients examined assumptions have been made which led to estimated values of 0.97 mrad for GSD and 2.0 mrad for LSD which must be considered as the upper limit of the real GSD and LSD. The influence of the different radiopharmaceuticals on the average radiation exposure of the population is discussed. (author).
Irradiation of the human body in diagnostic X-ray procedures results in different absorbed doses in the various body organs. A somatic dose index in formulated by applying the relative sensitivity of the human to each of the most important somatic effects and utilizing the absorbed dose in the affected organs. This quantity is used to convey a cumulative somatic impact and is computed for common radiographic views in diagnostic radiology as a function of beam quality for a nominal IR entrance exposure. Using typical X-ray beam qualities and exposures, the frequency of the various radiographic views that make up an examination and the frequencies of the various examinations in the national population, illustrative examples of the application of the somatic dose index are presented. (author).