Science.gov

Sample records for high level exposure

  1. Exposure to unusually high indoor radon levels

    SciTech Connect

    Rasheed, F.N. )

    1993-03-27

    Unusually high indoor radon concentrations were reported in a small village in western Tyrol, Austria. The authors have measured the seasonal course of indoor radon concentrations in 390 houses of this village. 71% of houses in winter and 33% in summer, showed radon values on the ground floor above the Austrian action level of 400 Bq/cm[sup 3]. This proportion results in an unusually high indoor radon exposure of the population. The radon source was an 8,700-year-old rock slide of granite gneiss, the largest of the alpine crystalline rocks. It has a strong emanating power because its rocks are heavily fractured and show a slightly increased uranium content. Previous reports show increased lung cancer mortality, myeloid leukemia, kidney cancer, melanoma, and prostate cancer resulting from indoor radon exposure. However, many studies fail to provide accurate information on indoor radon concentrations, classifying them merely as low, intermediate, and high, or they record only minor increases in indoor radon concentrations. Mortality data for 1970-91 were used to calculate age and sex standardized mortality rates (SMR) for 51 sites of carcinoma. The total population of Tyrol were controls. A significantly higher risk was recorded for lung cancer. The high SMR for lung cancer in female subjects is especially striking. Because the numbers were low for the other cancer sites, these were combined in one group to calculate the SMR. No significant increase in SMR was found for this group.

  2. Effects of high vs low-level radiation exposure

    SciTech Connect

    Bond, V.P.

    1983-01-01

    In order to appreciate adequately the various possible effects of radiation, particularly from high-level vs low-level radiation exposure (HLRE, vs LLRE), it is necessary to understand the substantial differences between (a) exposure as used in exposure-incidence curves, which are always initially linear and without threshold, and (b) dose as used in dose-response curves, which always have a threshold, above which the function is curvilinear with increasing slope. The differences are discussed first in terms of generally familiar nonradiation situations involving dose vs exposure, and then specifically in terms of exposure to radiation, vs a dose of radiation. Examples are given of relevant biomedical findings illustrating that, while dose can be used with HLRE, it is inappropriate and misleading the LLRE where exposure is the conceptually correct measure of the amount of radiation involved.

  3. Gestational exposure to high perchlorate concentrations in drinking water and neonatal thyroxine levels.

    PubMed

    Amitai, Yona; Winston, Gary; Sack, Joseph; Wasser, Janice; Lewis, Matthew; Blount, Benjamin C; Valentin-Blasini, Liza; Fisher, Nirah; Israeli, Avi; Leventhal, Alex

    2007-09-01

    To assess the effect of gestational perchlorate exposure through drinking water on neonatal thyroxine (T(4)). T(4) values were compared among newborns in Ramat Hasharon, Israel, whose mothers resided in suburbs where drinking water contained perchlorate < or = 340 microg/L (very high exposure, n = 97), 42-94 microg/L (high exposure, n = 216), and < 3 microg/L (low exposure, n = 843). In the very high and high exposure areas, T(4) values in newborns whose mothers drank tap water exclusively (as determined by a telephone interview) were analyzed as a subset. Serum perchlorate levels in blood from donors residing in the area were used as proxy indicators of exposure. Neonatal T(4) values (mean +/- SD) in the very high, high, and low exposure groups were 13.9 +/- 3.8, 13.9 +/- 3.4, and 14.0 +/- 3.5 microg/dL, respectively (p = NS). Serum perchlorate concentrations in blood from donors residing in areas corresponding to these groups were 5.99 +/- 3.89, 1.19 +/- 1.37, and 0.44 +/- 0.55 microg/L, respectively. T(4) levels of neonates with putative gestational exposure to perchlorate in drinking water were not statistically different from controls. This study finds no change in neonatal T(4) levels despite maternal consumption of drinking water that contains perchlorate at levels in excess of the Environmental Protection Agency (EPA) drinking water equivalent level (24.5 microg/L) based on the National Research Council reference dose (RfD) [0.7 microg/(kg.day)]. Therefore the perchlorate RfD is likely to be protective of thyroid function in neonates of mothers with adequate iodide intake.

  4. Recovery of otoacoustic emissions after high-level noise exposure in the American bullfrog

    PubMed Central

    Simmons, Dwayne D.; Lohr, Rachel; Wotring, Helena; Burton, Miriam D.; Hooper, Rebecca A.; Baird, Richard A.

    2014-01-01

    The American bullfrog (Rana catesbeiana) has an amphibian papilla (AP) that senses airborne, low-frequency sound and generates distortion product otoacoustic emissions (DPOAEs) similar to other vertebrate species. Although ranid frogs are typically found in noisy environments, the effects of noise on the AP have not been studied. First, we determined the noise levels that diminished DPOAE at 2f1–f2 using an f2 stimulus level at 80 dB SPL and that also produced morphological damage of the sensory epithelium. Second, we compared DPOAE (2f1–f2) responses with histopathologic changes occurring in bullfrogs after noise exposure. Consistent morphological damage, such as fragmented hair cells and missing bundles, as well as elimination of DPOAE responses were seen only after very high-level (>150 dB SPL) sound exposures. The morphological response of hair cells to noise differed along the mediolateral AP axis: medial hair cells were sensitive to noise and lateral hair cells were relatively insensitive to noise. Renewed or repaired hair cells were not observed until 9 days post-exposure. Following noise exposure, DPOAE responses disappeared within 24 h and then recovered to normal pre-exposure levels within 3–4 days. Our results suggest that DPOAEs in the bullfrog are sensitive to the initial period of hair cell damage. After noise-induced damage, the bullfrog AP has functional recovery mechanisms that do not depend on substantial hair cell regeneration or repair. Thus, the bullfrog auditory system might serve as an interesting model for investigation of ways to prevent noise damage. PMID:24501139

  5. The body weight loss during acute exposure to high-altitude hypoxia in sea level residents.

    PubMed

    Ge, Ri-Li; Wood, Helen; Yang, Hui-Huang; Liu, Yi-Ning; Wang, Xiu-Juan; Babb, Tony

    2010-12-25

    Weight loss is frequently observed after acute exposure to high altitude. However, the magnitude and rate of weight loss during acute exposure to high altitude has not been clarified in a controlled prospective study. The present study was performed to evaluate weight loss at high altitude. A group of 120 male subjects [aged (32±6) years] who worked on the construction of the Golmud-Lhasa Railway at Kunlun Mountain (altitude of 4 678 m) served as volunteer subjects for this study. Eighty-five workers normally resided at sea level (sea level group) and 35 normally resided at an altitude of 2 200 m (moderate altitude group). Body weight, body mass index (BMI), and waist circumference were measured in all subjects after a 7-day stay at Golmud (altitude of 2 800 m, baseline measurements). Measurements were repeated after 33-day working on Kunlun Mountain. In order to examine the daily rate of weight loss at high altitude, body weight was measured in 20 subjects from the sea level group (sea level subset group) each morning before breakfast for 33 d at Kunlun Mountain. According to guidelines established by the Lake Louise acute mountain sickness (AMS) consensus report, each subject completed an AMS self-report questionnaire two days after arriving at Kunlun Mountain. After 33-day stay at an altitude of 4 678 m, the average weight loss for the sea level group was 10.4% (range 6.5% to 29%), while the average for the moderate altitude group was 2.2% (-2% to 9.1%). The degree of weight loss (Δ weight loss) after a 33-day stay at an altitude of 4 678 m was significantly correlated with baseline body weight in the sea level group (r=0.677, P<0.01), while the correlation was absent in the moderate altitude group (r=0.296, P>0.05). In the sea level subset group, a significant weight loss was observed within 20 d, but the weight remained stable thereafter. AMS-score at high altitude was significantly higher in the sea level group (4.69±2.48) than that in the moderate

  6. High levels of sound pressure: acoustic reflex thresholds and auditory complaints of workers with noise exposure.

    PubMed

    Duarte, Alexandre Scalli Mathias; Ng, Ronny Tah Yen; de Carvalho, Guilherme Machado; Guimarães, Alexandre Caixeta; Pinheiro, Laiza Araujo Mohana; Costa, Everardo Andrade da; Gusmão, Reinaldo Jordão

    2015-01-01

    The clinical evaluation of subjects with occupational noise exposure has been difficult due to the discrepancy between auditory complaints and auditory test results. This study aimed to evaluate the contralateral acoustic reflex thresholds of workers exposed to high levels of noise, and to compare these results to the subjects' auditory complaints. This clinical retrospective study evaluated 364 workers between 1998 and 2005; their contralateral acoustic reflexes were compared to auditory complaints, age, and noise exposure time by chi-squared, Fisher's, and Spearman's tests. The workers' age ranged from 18 to 50 years (mean=39.6), and noise exposure time from one to 38 years (mean=17.3). We found that 15.1% (55) of the workers had bilateral hearing loss, 38.5% (140) had bilateral tinnitus, 52.8% (192) had abnormal sensitivity to loud sounds, and 47.2% (172) had speech recognition impairment. The variables hearing loss, speech recognition impairment, tinnitus, age group, and noise exposure time did not show relationship with acoustic reflex thresholds; however, all complaints demonstrated a statistically significant relationship with Metz recruitment at 3000 and 4000Hz bilaterally. There was no significance relationship between auditory complaints and acoustic reflexes. Copyright © 2015 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

  7. Affective and behavioral changes following exposure to traumatic events: the moderating effect of religiosity on avoidance behavior among students studying under a high level of terror event exposure.

    PubMed

    Korn, Liat; Zukerman, Gil

    2011-12-01

    The goals of this study were to examine the development of affective and behavioral changes following exposure to traumatic events among Israeli students studying under a high level of terror event exposure and to assess the effects of religiosity on those changes development. A questionnaire was administered to 770 students in the Ariel University Center in Judea and Samaria. Higher levels of terror exposure were associated with higher levels of avoidance behavior, subjective feelings of insecurity, and emotional distress. Higher religiosity moderated avoidance behavior, even when controlling for the level of objective exposure to terror events exposure, but had no influence on subjective sense of insecurity, or the level of emotional distress. These findings suggest that religiosity moderates behavioral changes development after traumatic event exposure mainly by reducing avoidance behavior.

  8. The identification of a selective dopamine D2 partial agonist, D3 antagonist displaying high levels of brain exposure.

    PubMed

    Holmes, Ian P; Blunt, Richard J; Lorthioir, Olivier E; Blowers, Stephen M; Gribble, Andy; Payne, Andrew H; Stansfield, Ian G; Wood, Martyn; Woollard, Patrick M; Reavill, Charlie; Howes, Claire M; Micheli, Fabrizio; Di Fabio, Romano; Donati, Daniele; Terreni, Silvia; Hamprecht, Dieter; Arista, Luca; Worby, Angela; Watson, Steve P

    2010-03-15

    The identification of a highly selective D(2) partial agonist, D(3) antagonist tool molecule which demonstrates high levels of brain exposure and selectivity against an extensive range of dopamine, serotonin, adrenergic, histamine, and muscarinic receptors is described.

  9. Risk estimation with epidemiologic data when response attenuates at high-exposure levels.

    PubMed

    Steenland, Kyle; Seals, Ryan; Klein, Mitch; Jinot, Jennifer; Kahn, Henry D

    2011-06-01

    In occupational studies, which are commonly used for risk assessment for environmental settings, estimated exposure-response relationships often attenuate at high exposures. Relative risk (RR) models with transformed (e.g., log- or square root-transformed) exposures can provide a good fit to such data, but resulting exposure-response curves that are supralinear in the low-dose region may overestimate low-dose risks. Conversely, a model of untransformed (linear) exposure may underestimate risks attributable to exposures in the low-dose region. We examined several models, seeking simple parametric models that fit attenuating exposure-response data well. We have illustrated the use of both log-linear and linear RR models using cohort study data on breast cancer and exposure to ethylene oxide. Linear RR models fit the data better than do corresponding log-linear models. Among linear RR models, linear (untransformed), log-transformed, square root-transformed, linear-exponential, and two-piece linear exposure models all fit the data reasonably well. However, the slopes of the predicted exposure-response relations were very different in the low-exposure range, which resulted in different estimates of the exposure concentration associated with a 1% lifetime excess risk (0.0400, 0.00005, 0.0016, 0.0113, and 0.0100 ppm, respectively). The linear (in exposure) model underestimated the categorical exposure-response in the low-dose region, whereas log-transformed and square root-transformed exposure models overestimated it. Although a number of models may fit attenuating data well, models that assume linear or nearly linear exposure-response relations in the low-dose region of interest may be preferred by risk assessors, because they do not depend on the choice of a point of departure for linear low-dose extrapolation and are relatively easy to interpret.

  10. Respiratory Effects of High Levels of Particulate Exposure in a Cohort of Traffic Police in Kathmandu, Nepal.

    PubMed

    Shakya, Kabindra M; Rupakheti, Maheswar; Aryal, Krishna; Peltier, Richard E

    2016-06-01

    To investigate the traffic-related PM2.5 and black carbon (BC) exposures and assess their health effects. Personal exposure to PM2.5 and BC levels were monitored in a cohort of traffic police (n = 53) at six locations in Kathmandu Valley, Nepal during dry and rainy seasons in 2014. Mean on-road exposure levels of PM2.5 and BC ranged from 34 to 193 μg/m and 12 to 28 μgC/m, respectively, and were associated with an acute decline in lung function. Use of N95 mask had clear benefits reducing the lung function decreases after occupational exposures when masks were worn for just half of a workweek. Exposure of high levels of PM2.5 was associated with reduced lung function. Increased levels of BC exposure led to reduced lung function in non-smoking traffic officers with non-normal spirometry observations.

  11. Is beryllium-induced lung cancer caused only by soluble forms and high exposure levels?

    PubMed

    Schubauer-Berigan, Mary K; Couch, James R; Deddens, James A

    2017-08-01

    The US Occupational Safety and Health Administration (OSHA) recently proposed a permissible exposure limit of 0.2 µg/m(3) for beryllium, based partly on extrapolated estimates of lung cancer risk from a pooled occupational cohort. The purpose of the present analysis was to evaluate whether cohort members exposed at lower levels to mainly insoluble forms of beryllium exhibit increased risk of lung cancer. We conducted Cox proportional hazards regression analyses among 75 lung cancer cases in age-based risk sets within two lower exposure plants in the pooled cohort followed from 1940 to 2005. We used categorical and power models to evaluate exposure-response patterns for mean and cumulative beryllium exposures in the two-plant cohort, comparing findings with the full pooled cohort. We also evaluated the distribution of exposure-years in each cohort by solubility class (soluble, insoluble and mixed). 98% of workers in the two-plant cohort were hired between 1955 and 1969. The mean beryllium exposure averaged 1.3 µg/m(3) and the predominant form was insoluble. Adjusting for confounders, we observed a monotonic increase in lung cancer mortality across exposure categories in the two-plant cohort. The exposure-response coefficients (per unit ln exposure) were 0.270 (p=0.061) for mean exposure and 0.170 (p=0.033) for cumulative exposure, compared with 0.155 and 0.094 (respectively) in the full cohort. The low-exposure levels at these two plants and the predominance of insoluble beryllium suggest that the overall pooled cohort findings on which OSHA's lung cancer risk assessment is based are relevant for current workers exposed to any form of beryllium. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  12. NEUROBEHAVIORAL EFFECTS OF CHRONIC DIETARY AND REPEATED HIGH-LEVEL SPIKE EXPOSURE TO CHLORPYRIFOS IN RATS.

    EPA Science Inventory

    This study aimed to model long-term subtoxic human exposure to an organophosphorus pesticide, chlorpyrifos, and to examine the influence of that exposure on the response to intermittent high-dose acute challenges. Adult rats were maintained on a chlorpyrifos-containing diet to p...

  13. NEUROBEHAVIORAL EFFECTS OF CHRONIC DIETARY AND REPEATED HIGH-LEVEL SPIKE EXPOSURE TO CHLORPYRIFOS IN RATS.

    EPA Science Inventory

    This study aimed to model long-term subtoxic human exposure to an organophosphorus pesticide, chlorpyrifos, and to examine the influence of that exposure on the response to intermittent high-dose acute challenges. Adult Long-Evans male rats were maintained at 350g body weight by...

  14. NEUROBEHAVIORAL EFFECTS OF CHRONIC DIETARY AND REPEATED HIGH-LEVEL SPIKE EXPOSURE TO CHLORPYRIFOS IN RATS.

    EPA Science Inventory

    This study aimed to model long-term subtoxic human exposure to an organophosphorus pesticide, chlorpyrifos, and to examine the influence of that exposure on the response to intermittent high-dose acute challenges. Adult rats were maintained on a chlorpyrifos-containing diet to p...

  15. NEUROBEHAVIORAL EFFECTS OF CHRONIC DIETARY AND REPEATED HIGH-LEVEL SPIKE EXPOSURE TO CHLORPYRIFOS IN RATS.

    EPA Science Inventory

    This study aimed to model long-term subtoxic human exposure to an organophosphorus pesticide, chlorpyrifos, and to examine the influence of that exposure on the response to intermittent high-dose acute challenges. Adult Long-Evans male rats were maintained at 350g body weight by...

  16. The effects of intermittent high asbestos exposure (peak dose levels) on the lungs of rats.

    PubMed Central

    Davis, J. M.; Beckett, S. T.; Bolton, R. E.; Donaldson, K.

    1980-01-01

    Four groups of rats were treated by inhalation with the UICC preparations of amosite or chrysotile in order to explore the effects of intermittent high dust concentrations (peak dosing). For each of the 2 asbestos types one group of rats was treated for 5 days each week, 7 h a day, for 1 year. Two other groups were treated with amosite or chrysotile at 5 times the previous dose for 1 day each week for 1 year. Results showed that the lung dust levels of both chrysotile or amosite in the lungs of rats after the 12-month inhalation period were similar regardless of whether "peak" or "even" dosing had been used. During the following 6 months, asbestos was cleared from the "peak" chrysotile group more slowly than the "even" chrysotile group but clearance from the "peak" amosite group was faster than that found after "even" dosing with amosite. Levels of early peribronchial fibrosis were generally lower for the "peak" dosing groups than for "even" dosing although levels of interstitial fibrosis were slightly higher following "peak" dosing. The incidence of pulmonary neoplasms did not differ between the "peak"-dosing and "even"-dosing experiments. These findings therefore give no indication that short periods of high dust exposure in an asbestos factory would result in a significantly greater hazard than would be indicated by the raised overall dust counts for the day in question. Images Fig. 3 PMID:7426382

  17. Concentration of butadiene diepoxide in rat tissues following low-level and high-level inhalation exposures to 1,3-butadiene

    SciTech Connect

    Thornton-Manning, J.R.; Dahl, A.R.; Bechtold, W.E.

    1996-12-31

    1,3-Butadiene (BD), a chemical used extensively in the rubber industry, is carcinogenic in mice following chronic exposures as low as 6.25 ppm, but is carcinogenic in rats only after exposures of 1000 and 8000 ppm. Previous studies in our laboratory have shown that levels of the highly mutagenic metabolite, butadiene diepoxide (BDO{sub 2}), are much greater in mouse tissues than rat tissues after exposures of 62.5 ppm BD. We hypothesized that this metabolite is the primary determinant of BD carcinogenicity and hence would increase in rats following high-level exposures to BD. Female Sprague-Dawley rats were exposed to 62.5 ppm BD (low-level) and 8000 ppm BD (high-level) for either 6 h or 6 h daily for 10 days. Blood was collected immediately following the exposure and analyzed for the presence of BDO{sub 2} by multidimensional gas chromatography/mass spectrometry. Following exposures of 6 h or 6 h/day for 10 days to 62.5 ppm BD, levels of BDO{sub 2} in rat blood were 14 {+-} 2 (mean {+-} SE) and 17 {+-} 2 pmol/g, respectively. Levels of BDO{sub 2} in mouse blood following identical exposures were 15- to 25-fold greater than those observed in rat blood. Following exposures of rats to 8000 ppm BD, blood levels of BDO{sub 2} were very similar to those observed after exposures to 62.5 ppm RD (11 {+-} 1 and 17{+-}1 pmol/g following exposures of 6 h and 6 h/day for 10 days, respectively). This study shows that levels of BDO{sub 2}, do not increase in the rat following a high-level exposure to BD, suggesting that factors other than the production of this metabolite may be involved in BD-induced tumors in rats.

  18. Exposure to Organic Solvents Used in Dry Cleaning Reduces Low and High Level Visual Function

    PubMed Central

    Jiménez Barbosa, Ingrid Astrid

    2015-01-01

    were also significantly higher and almost double than that obtained from non dry-cleaners. However, reaction time performance on both parallel and serial visual search was not different between dry cleaners and non dry-cleaners. Conclusions Exposure to occupational levels of organic solvents is associated with neurotoxicity which is in turn associated with both low level deficits (such as the perception of contrast and discrimination of colour) and high level visual deficits such as the perception of global form and motion, but not visual search performance. The latter finding indicates that the deficits in visual function are unlikely to be due to changes in general cognitive performance. PMID:25933026

  19. Common Sole Larvae Survive High Levels of Pile-Driving Sound in Controlled Exposure Experiments

    PubMed Central

    Bolle, Loes J.; de Jong, Christ A. F.; Bierman, Stijn M.; van Beek, Pieter J. G.; van Keeken, Olvin A.; Wessels, Peter W.; van Damme, Cindy J. G.; Winter, Hendrik V.; de Haan, Dick; Dekeling, René P. A.

    2012-01-01

    In view of the rapid extension of offshore wind farms, there is an urgent need to improve our knowledge on possible adverse effects of underwater sound generated by pile-driving. Mortality and injuries have been observed in fish exposed to loud impulse sounds, but knowledge on the sound levels at which (sub-)lethal effects occur is limited for juvenile and adult fish, and virtually non-existent for fish eggs and larvae. A device was developed in which fish larvae can be exposed to underwater sound. It consists of a rigid-walled cylindrical chamber driven by an electro-dynamical sound projector. Samples of up to 100 larvae can be exposed simultaneously to a homogeneously distributed sound pressure and particle velocity field. Recorded pile-driving sounds could be reproduced accurately in the frequency range between 50 and 1000 Hz, at zero to peak pressure levels up to 210 dB re 1µPa2 (zero to peak pressures up to 32 kPa) and single pulse sound exposure levels up to 186 dB re 1µPa2s. The device was used to examine lethal effects of sound exposure in common sole (Solea solea) larvae. Different developmental stages were exposed to various levels and durations of pile-driving sound. The highest cumulative sound exposure level applied was 206 dB re 1µPa2s, which corresponds to 100 strikes at a distance of 100 m from a typical North Sea pile-driving site. The results showed no statistically significant differences in mortality between exposure and control groups at sound exposure levels which were well above the US interim criteria for non-auditory tissue damage in fish. Although our findings cannot be extrapolated to fish larvae in general, as interspecific differences in vulnerability to sound exposure may occur, they do indicate that previous assumptions and criteria may need to be revised. PMID:22431996

  20. Risk Estimation with Epidemiologic Data When Response Attenuates at High-Exposure Levels

    PubMed Central

    Steenland, Kyle; Seals, Ryan; Klein, Mitch; Jinot, Jennifer; Kahn, Henry D.

    2011-01-01

    Background In occupational studies, which are commonly used for risk assessment for environmental settings, estimated exposure–response relationships often attenuate at high exposures. Relative risk (RR) models with transformed (e.g., log- or square root–transformed) exposures can provide a good fit to such data, but resulting exposure–response curves that are supralinear in the low-dose region may overestimate low-dose risks. Conversely, a model of untransformed (linear) exposure may underestimate risks attributable to exposures in the low-dose region. Methods We examined several models, seeking simple parametric models that fit attenuating exposure–response data well. We have illustrated the use of both log-linear and linear RR models using cohort study data on breast cancer and exposure to ethylene oxide. Results Linear RR models fit the data better than do corresponding log-linear models. Among linear RR models, linear (untransformed), log-transformed, square root–transformed, linear-exponential, and two-piece linear exposure models all fit the data reasonably well. However, the slopes of the predicted exposure–response relations were very different in the low-exposure range, which resulted in different estimates of the exposure concentration associated with a 1% lifetime excess risk (0.0400, 0.00005, 0.0016, 0.0113, and 0.0100 ppm, respectively). The linear (in exposure) model underestimated the categorical exposure–response in the low-dose region, whereas log-transformed and square root–transformed exposure models overestimated it. Conclusion Although a number of models may fit attenuating data well, models that assume linear or nearly linear exposure–response relations in the low-dose region of interest may be preferred by risk assessors, because they do not depend on the choice of a point of departure for linear low-dose extrapolation and are relatively easy to interpret. PMID:21220221

  1. Increased Artemis levels confer radioresistance to both high and low LET radiation exposures.

    PubMed

    Sridharan, Deepa M; Whalen, Mary K; Almendrala, Donna; Cucinotta, Francis A; Kawahara, Misako; Yannone, Steven M; Pluth, Janice M

    2012-06-19

    Artemis has a defined role in V(D)J recombination and has been implicated in the repair of radiation induced double-strand breaks. However the exact function(s) of Artemis in DNA repair and its preferred substrate(s) in vivo remain undefined. Our previous work suggests that Artemis is important for the repair of complex DNA damage like that inflicted by high Linear Energy Transfer (LET) radiation. To establish the contribution of Artemis in repairing DNA damage caused by various radiation qualities, we evaluated the effect of over-expressing Artemis on cell survival, DNA repair, and cell cycle arrest after exposure to high and low LET radiation. Our data reveal that Artemis over-expression confers marked radioprotection against both types of radiation, although the radioprotective effect was greater following high LET radiation. Inhibitor studies reveal that the radioprotection imparted by Artemis is primarily dependent on DNA-PK activity, and to a lesser extent on ATM kinase activity. Together, these data suggest a DNA-PK dependent role for Artemis in the repair of complex DNA damage. These findings indicate that Artemis levels significantly influence radiation toxicity in human cells and suggest that Artemis inhibition could be a practical target for adjuvant cancer therapies.

  2. Increased Artemis levels confer radioresistance to both high and low LET radiation exposures

    PubMed Central

    2012-01-01

    Background Artemis has a defined role in V(D)J recombination and has been implicated in the repair of radiation induced double-strand breaks. However the exact function(s) of Artemis in DNA repair and its preferred substrate(s) in vivo remain undefined. Our previous work suggests that Artemis is important for the repair of complex DNA damage like that inflicted by high Linear Energy Transfer (LET) radiation. To establish the contribution of Artemis in repairing DNA damage caused by various radiation qualities, we evaluated the effect of over-expressing Artemis on cell survival, DNA repair, and cell cycle arrest after exposure to high and low LET radiation. Results Our data reveal that Artemis over-expression confers marked radioprotection against both types of radiation, although the radioprotective effect was greater following high LET radiation. Inhibitor studies reveal that the radioprotection imparted by Artemis is primarily dependent on DNA-PK activity, and to a lesser extent on ATM kinase activity. Together, these data suggest a DNA-PK dependent role for Artemis in the repair of complex DNA damage. Conclusions These findings indicate that Artemis levels significantly influence radiation toxicity in human cells and suggest that Artemis inhibition could be a practical target for adjuvant cancer therapies. PMID:22713703

  3. Safety levels for exposure of cornea and lens to very high-frequency ultrasound.

    PubMed

    Silverman, R H; Lizzi, F L; Ursea, B G; Cozzarelli, L; Ketterling, J A; Deng, C X; Folberg, R; Coleman, D J

    2001-09-01

    Very high-frequency (50-MHz) ultrasound is widely used for imaging the anterior segment of the eye. Our aim was to determine whether exposures to ultrasound at and above those used in diagnostic imaging systems might cause bioeffects in ocular tissues. We characterized the output parameters of a polyvinylidene difluoride transducer using a needle hydrophone. We exposed sites on the cornea or lens of rabbits for up to 30 minutes at a 10-kHz pulse repetition frequency. Tissue obtained immediately or 24 hours after exposure was examined by light microscopy. A numeric model was implemented to calculate expected temperature elevations in the cornea and lens under experimental conditions. No tissue changes were observed directly or by slit lamp. Light microscopy showed no abnormalities attributable to ultrasound exposure. Simulations showed that even long-term exposures should produce temperature elevations of less than 1 degree C in both the cornea and lens. With the use of exposure parameters 4 to 5 orders of magnitude greater than encountered in a clinical situation, no tissue changes were observed. This is consistent with the small (0.2 degrees C) temperature rises computed in simulations. The lack of biological effects is attributable to the small dimensions of the focal zone, allowing rapid dissipation of heat, and the low total acoustic power produced by the transducer.

  4. Hypertension`s lead connection: Does low-level exposure to lead cause high blood pressure?

    SciTech Connect

    Fackelmann, K.

    1996-06-15

    {open_quotes}Paying for the sins of the past.{close_quotes} is how researcher Howard Hu describes a proposed disease process in which lead stored for decades in the skeleton puts people at risk of high blood pressure. Previous research has linked this silvery white, poisonous metal to a host of ill effects in children, including learning disabilities, behavior problems, and brain damage. Now, Hu`s study indicates that past exposure may be causing today`s high blood pressure. If he`s right, the public health impact would be significant. {open_quotes}Tens of millions of Americans have been exposed over the years to lead,{close_quotes} says Philip J. Landrigan of Mount Sinai Medical Center in New York. {open_quotes}Adults today grew up at a time when we were still putting several hundred thousand tons of lead into gasoline each year.{close_quotes} Indeed, the men who developed high blood pressure during the recent study had in their bones lead concentrations, or lead burdens, that came from decades of everyday exposure. Such exposures resulted principally from breathing in fumes from leaded gasoline, drinking tap water from lead pipes or pipes soldered with lead, and inhaling or ingesting lead-laced paint dust or chips. This article goes on to discuss other studies and questions which still need to be answered.

  5. Significant pulmonary response to a brief high-level, nose-only nitrogen dioxide exposure: an interspecies dosimetry perspective.

    PubMed

    Elsayed, Nabil M; Gorbunov, Nikolai V; Mayorga, Maria A; Kagan, Valerian E; Januszkiewicz, Adolph J

    2002-10-01

    Brief, high-level nitrogen dioxide (NO(2)) exposures are major hazards during fires and heat-generating explosions. To characterize the lung response to a brief high-level NO(2) exposure, we exposed two groups (n = 5) of 325-375 g, male, Sprague-Dawley rats to either 200 +/- 5 ppm (376 +/- 9 mg/m(3)) NO(2) or room air for 15 min. The rats were nose-only exposed in a multiport exposure chamber fitted with pressure transducers to monitor their respiration during exposure. One hour after exposure, we euthanized the rats, collected blood samples, lavaged the lungs with warm saline, and then excised them. One lung lobe was cooled to -196 degrees C and used for low-temperature electron paramagentic resonance (EPR) analysis. The remainder was homogenized and used for biochemical analyses. Inspired minute ventilation (V(i)) during exposure decreased 59% (p < 0.05). Calculated total inspired dose was 0.880 mg NO(2). In lung lavage, both total and alveolar macrophage cell counts declined (approximately 75%, p < 0.05), but epithelial cell count increased 8.5-fold. Lung weight increased 40% (p < 0.05) after exposure. In the blood, potassium and methemoglobin increased 45 and 18% (p < 0.05), respectively; glucose, lactate, and total hemoglobin were not altered significantly. EPR analysis of lung tissue revealed hemoglobin oxidation and carbon-centered radical formation. Vitamins E and C and uric acid were depleted, and lipid peroxidation measured by three different methods (TBARS, conjugated dienes, and fluorescent peroxidation end products) was elevated, but total protein, DNA, and lipid contents were unchanged. These observations combined demonstrate that a brief (15 min) high-level (200 ppm) NO(2) exposure of rats was sufficient to cause significant damage. However, comparison of the exposure dose normalized to rat body weight with previously reported sheep and estimated human values revealed significant differences. This raises a question about interspecies dosimetry and

  6. High Throughput Exposure Prioritization of Chemicals Using a Screening-Level Probabilistic SHEDS-Lite Exposure Model

    EPA Science Inventory

    These novel modeling approaches for screening, evaluating and classifying chemicals based on the potential for biologically-relevant human exposures will inform toxicity testing and prioritization for chemical risk assessment. The new modeling approach is derived from the Stocha...

  7. Effects of long-term exposure of tuffs to high-level nuclear waste-repository conditions. Preliminary report

    SciTech Connect

    Blacic, J.; Carter, J.; Halleck, P.; Johnson, P.; Shankland, T.; Andersen, R.; Spicochi, K.; Heller, A.

    1982-02-01

    Tests have been performed to explore the effects of extended exposure of tuffs from the southwestern portion of the Nevada Test Site to temperatures and pressures similar to those that will be encountered in a high-level nuclear waste repository. Tuff samples ranging from highly welded, nonzeolitized to unwelded, highly zeolitized varieties were subjected to temperatures of 80, 120, and 180{sup 0}C; confining pressures of 9.7 and 19.7 MPa; and water-pore pressures of 0.5 to 19.7 MPa for durations of 2 to 6 months. The following basic properties were measured before and after exposure and compared: tensile strength, uniaxial compressive strength, grain density, porosity, mineralogy, permeability, thermal expansion, and thermal conductivity. Depending on rock type and exposure conditions, significant changes in ambient tensile strength, compressive strength, grain density, and porosity were measured. Mineralogic examination, permeability, and thermal property measurements remain to be completed.

  8. Exposure to medium and high ambient levels of ozone causes adverse systemic inflammatory and cardiac autonomic effects

    PubMed Central

    Wong, Hofer; Donde, Aneesh; Frelinger, Jessica; Dalton, Sarah; Ching, Wendy; Power, Karron; Balmes, John R.

    2015-01-01

    Epidemiological evidence suggests that exposure to ozone increases cardiovascular morbidity. However, the specific biological mechanisms mediating ozone-associated cardiovascular effects are unknown. To determine whether short-term exposure to ambient levels of ozone causes changes in biomarkers of cardiovascular disease including heart rate variability (HRV), systemic inflammation, and coagulability, 26 subjects were exposed to 0, 100, and 200 ppb ozone in random order for 4 h with intermittent exercise. HRV was measured and blood samples were obtained immediately before (0 h), immediately after (4 h), and 20 h after (24 h) each exposure. Bronchoscopy with bronchoalveolar lavage (BAL) was performed 20 h after exposure. Regression modeling was used to examine dose-response trends between the endpoints and ozone exposure. Inhalation of ozone induced dose-dependent adverse changes in the frequency domains of HRV across exposures consistent with increased sympathetic tone [increase of (parameter estimate ± SE) 0.4 ± 0.2 and 0.3 ± 0.1 in low- to high-frequency domain HRV ratio per 100 ppb increase in ozone at 4 h and 24 h, respectively (P = 0.02 and P = 0.01)] and a dose-dependent increase in serum C-reactive protein (CRP) across exposures at 24 h [increase of 0.61 ± 0.24 mg/l in CRP per 100 ppb increase in ozone (P = 0.01)]. Changes in HRV and CRP did not correlate with ozone-induced local lung inflammatory responses (BAL granulocytes, IL-6, or IL-8), but changes in HRV and CRP were associated with each other after adjustment for age and ozone level. Inhalation of ozone causes adverse systemic inflammatory and cardiac autonomic effects that may contribute to the cardiovascular mortality associated with short-term exposure. PMID:25862833

  9. Exposure to medium and high ambient levels of ozone causes adverse systemic inflammatory and cardiac autonomic effects.

    PubMed

    Arjomandi, Mehrdad; Wong, Hofer; Donde, Aneesh; Frelinger, Jessica; Dalton, Sarah; Ching, Wendy; Power, Karron; Balmes, John R

    2015-06-15

    Epidemiological evidence suggests that exposure to ozone increases cardiovascular morbidity. However, the specific biological mechanisms mediating ozone-associated cardiovascular effects are unknown. To determine whether short-term exposure to ambient levels of ozone causes changes in biomarkers of cardiovascular disease including heart rate variability (HRV), systemic inflammation, and coagulability, 26 subjects were exposed to 0, 100, and 200 ppb ozone in random order for 4 h with intermittent exercise. HRV was measured and blood samples were obtained immediately before (0 h), immediately after (4 h), and 20 h after (24 h) each exposure. Bronchoscopy with bronchoalveolar lavage (BAL) was performed 20 h after exposure. Regression modeling was used to examine dose-response trends between the endpoints and ozone exposure. Inhalation of ozone induced dose-dependent adverse changes in the frequency domains of HRV across exposures consistent with increased sympathetic tone [increase of (parameter estimate ± SE) 0.4 ± 0.2 and 0.3 ± 0.1 in low- to high-frequency domain HRV ratio per 100 ppb increase in ozone at 4 h and 24 h, respectively (P = 0.02 and P = 0.01)] and a dose-dependent increase in serum C-reactive protein (CRP) across exposures at 24 h [increase of 0.61 ± 0.24 mg/l in CRP per 100 ppb increase in ozone (P = 0.01)]. Changes in HRV and CRP did not correlate with ozone-induced local lung inflammatory responses (BAL granulocytes, IL-6, or IL-8), but changes in HRV and CRP were associated with each other after adjustment for age and ozone level. Inhalation of ozone causes adverse systemic inflammatory and cardiac autonomic effects that may contribute to the cardiovascular mortality associated with short-term exposure.

  10. Suppression of spore germination and aflatoxin biosynthesis in Aspergillus parasiticus during and after exposure to high levels of phosphine.

    PubMed

    Antonacci, L; Salvat, A E; Faifer, G C; Godoy, H M

    1999-01-01

    Agar cultures of toxigenic Aspergillus parasiticus NRRL 2999 were exposed to phosphine (PH3), in levels ranging from 0 to 2000 ppm (vol/vol). It was found that with PH3 concentrations of 400 ppm or higher the growth of the fungus was totally arrested. When PH3 was vented and the agar plates were exposed to open air, 100% of the initial CFU developed into fully grown colonies after PH3 levels below 300 ppm, but at higher PH3 concentrations only 50% of the colonies developed. The same strain of A. parasiticus was inoculated into high moisture corn under conditions highly favorable for aflatoxin production, and it was exposed to a range of PH3 levels. After exposure to 500 ppm PH3, both fungal growth and aflatoxin synthesis resumed shortly after elimination of the toxic gas, but after exposure to PH3 levels of 1000 ppm and higher, the physical appearance of the contaminated corn was remarkably changed, showing reduced mycelial growth and almost complete absence of green pigmentation. In addition, aflatoxin synthesis was totally absent for the remainder of the experiment (20 days). These results strongly suggest that exposure to PH3 levels of 1000 ppm or higher could bring about persistent metabolic changes in surviving Aspergillus organisms.

  11. Biological effects of short, high-level exposure to gases: sulfur dioxide. Phase report, May 1979-May 1980

    SciTech Connect

    Normandy, M.J.; Szlyk, P.; Brienza, B.

    1980-05-01

    This report presents an analysis and synthesis of the available literature concerned with possible health effects of exposures to sulfur dioxide. The U.S. Army is concerned with short, high-level exposures to sulfur dioxide that may exceed present threshold limit values of the American Conference of Governmental Industrial Hygienists (5 ppm, 13 mg/cu m as a time-weighted average. The organ systems primarily affected by exposure to sulfur dioxide are the respiratory tract and the eyes. Certain neurologic effects (including suppression of dark adaptation and decreased light sensitivity) are of unknown significance and warrant further study. Below about 5 ppm, there are no significant irritant or pulmonary effects. Between 5 and 8 ppm (13 and 20.8 mg/cu m), most people will experience coughing, moderate irritation of the eyes, nose, and throat, and bronchoconstriction. At about 10 ppm (26 mg/cu m), moderate to severe eye irritation.

  12. Exposure of Salmonella enterica Serovar Typhimurium to High Level Biocide Challenge Can Select Multidrug Resistant Mutants in a Single Step

    PubMed Central

    Whitehead, Rebekah N.; Overton, Tim W.; Kemp, Caroline L.; Webber, Mark A.

    2011-01-01

    Background Biocides are crucial to the prevention of infection by bacteria, particularly with the global emergence of multiply antibiotic resistant strains of many species. Concern has been raised regarding the potential for biocide exposure to select for antibiotic resistance due to common mechanisms of resistance, notably efflux. Methodology/Principal Findings Salmonella enterica serovar Typhimurium was challenged with 4 biocides of differing modes of action at both low and recommended-use concentration. Flow cytometry was used to investigate the physiological state of the cells after biocide challenge. After 5 hours exposure to biocide, live cells were sorted by FACS and recovered. Cells recovered after an exposure to low concentrations of biocide had antibiotic resistance profiles similar to wild-type cells. Live cells were recovered after exposure to two of the biocides at in-use concentration for 5 hours. These cells were multi-drug resistant and accumulation assays demonstrated an efflux phenotype of these mutants. Gene expression analysis showed that the AcrEF multidrug efflux pump was de-repressed in mutants isolated from high-levels of biocide. Conclusions/Significance These data show that a single exposure to the working concentration of certain biocides can select for mutant Salmonella with efflux mediated multidrug resistance and that flow cytometry is a sensitive tool for identifying biocide tolerant mutants. The propensity for biocides to select for MDR mutants varies and this should be a consideration when designing new biocidal formulations. PMID:21829527

  13. Mummichog (Fundulus heteroclitus) continue to successfully produce eggs after exposure to high levels of 17α-ethinylestradiol.

    PubMed

    Bosker, Thijs; Munkittrick, Kelly R; Lister, Andrea; MacLatchy, Deborah L

    2016-05-01

    17α-Ethinylestradiol (EE2) is a potent estrogen used in birth-control pills. Previous laboratory and field studies have shown negative impacts in a variety of fish species after exposure to low levels of EE2, most notably a nearly complete shutdown of egg production. The present study demonstrates that mummichog (Fundulus heteroclitus), a small-bodied estuarine species, is able to continue to produce eggs after exposure for 28 d to 100 ng of EE2/L. No effect of EE2 on egg production was observed, whereas a >35-fold increase in vitellogenin (vtg 1) gene expression in males was found. The lack of response in egg production in fish exposed to high levels of EE2 warrants further investigations on species-specific responses to estrogens and endocrine disruptors in general. © 2015 SETAC.

  14. Distinct Responses of Mycobacterium smegmatis to Exposure to Low and High Levels of Hydrogen Peroxide

    PubMed Central

    Li, Xiaojing; Wu, Jun; Han, Jiao; Hu, Yongfei; Mi, Kaixia

    2015-01-01

    Hydrogen peroxide (H2O2) is a natural oxidant produced by aerobic organisms and gives rise to oxidative damage, including DNA mutations, protein inactivation and lipid damage. The genus Mycobacterium utilizes redox sensors and H2O2 scavenging enzymes for the detoxification of H2O2. To date, the precise response to oxidative stress has not been fully elucidated. Here, we compared the effects of different levels of H2O2 on transcription in M. smegmatis using RNA-sequencing. A 0.2 mM H2O2 treatment had little effect on the growth and viability of M. smegmatis whereas 7 mM H2O2 was lethal. Analysis of global transcription showed that 0.2 mM H2O2 induced relatively few changes in gene expression, whereas a large proportion of the mycobacterial genome was found to be differentially expressed after treatment with 7 mM H2O2. Genes differentially expressed following treatment with 0.2 mM H2O2 included those coding for proteins involved in glycolysis-gluconeogenesis and fatty acid metabolism pathways, and expression of most genes encoding ribosomal proteins was lower following treatment with 7 mM H2O2. Our analysis shows that M. smegmatis utilizes the sigma factor MSMEG_5214 in response to 0.2 mM H2O2, and the RpoE1 sigma factors MSMEG_0573 and MSMEG_0574 in response to 7 mM H2O2. In addition, different transcriptional regulators responded to different levels of H2O2: MSMEG_1919 was induced by 0.2 mM H2O2, while high-level induction of DevR occurred in response to 7 mM H2O2. We detected the induction of different detoxifying enzymes, including genes encoding KatG, AhpD, TrxB and Trx, at different levels of H2O2 and the detoxifying enzymes were expressed at different levels of H2O2. In conclusion, our study reveals the changes in transcription that are induced in response to different levels of H2O2 in M. smegmatis. PMID:26225431

  15. Cognitive and psychomotor responses to high-altitude exposure in sea level and high-altitude residents of Ecuador.

    PubMed

    Davis, John E; Wagner, Dale R; Garvin, Nathan; Moilanen, David; Thorington, Jessica; Schall, Cory

    2015-02-04

    High-altitude inhabitants have cardiovascular and respiratory adaptations that are advantageous for high-altitude living, but they may have impaired cognitive function. This study evaluated the influence of altitude of residence on cognitive and psychomotor function upon acute exposure to very high altitude. Ecuadorians (31 residing at 0-1,500 m [LOW], 78 from 1,501-3,000 m [MOD], and 23 living >3,000 m [HIGH]) were tested upon their arrival to a hut at 4,860 m on Mount Chimborazo. Cognitive/psychomotor measurements included a go-no-go test (responding to a non-visual stimulus), a verbal fluency test (verbalizing a series of words specific to a particular category), and a hand movement test (rapidly repeating a series of hand positions). Mean differences between the three altitude groups on these cognitive/psychomotor tests were evaluated with one-way ANOVA. There were no significant differences (p = 0.168) between LOW, MOD, and HIGH for the verbal fluency test. However, the go-no-go test was significantly lower (p < 0.001) in the HIGH group (8.8 ± 1.40 correct responses) than the LOW (9.8 ± 0.61) or MOD (9.8 ± 0.55) groups, and both MOD (97.9 ± 31.2) and HIGH (83.5 ± 26.7) groups completed fewer correct hand movements than the LOW (136.6 ± 37.9) subjects (p < 0.001). Based on this field study, high-altitude residents appear to have some impaired cognitive function suggesting the possibility of maladaptation to long-term exposure to hypobaric hypoxia.

  16. Biological effects of short, high-level exposure to gases: ammonia. Phase report, May 1979-May 1980

    SciTech Connect

    Legters, L.J.

    1980-05-01

    This report presents an analysis and synthesis of the available literature concerned with possible health and performance effects of exposures to ammonia. The US Army's concern is with short, high-level exposures that may exceed present threshold limit values of the American Conference of Governmental Industrial Hygienists (25 ppm or 17 mg/cum as a TWA and a ceiling of 35 ppm or 24 mg/cum for 15 minutes). The organs primarily affected by exposure to ammonia gas are the respiratory tract and the eyes. During brief exposures to concentrations of 500 ppm (348 mg/cum) or less, the biologic responses are immediate, reversible, and mainly irritant. Below 50 ppm (35 mg/cum), there are no significant effects except that the odor of ammonia is detectable. Between 50-100 ppm (35-70 mg/cum), most people experience some degree of irritation of the eyes, nose and throat. There is some evidence indicating that personnel may become acclimated to the irritant effects after only 1 or 2 weeks of inhalation.

  17. Plant responses to short- and long-term exposures to high carbon dioxide levels in closed environments

    NASA Astrophysics Data System (ADS)

    Grodzinski, B.; Woodrow, L.; Leonardos, E. D.; Dixon, M.; Tsujita, M. J.

    1996-01-01

    When higher plants are exposed to elevated levels of CO_2 for both short- and long-term periods photosynthetic C-gain and photoassimilate export from leaves are generally increased. Water use efficiency is increased on a leaf area basis. During long-term exposures, photosynthesis rates on leaf and whole plant bases are altered in a species specific manner. The most common pattern in C_3 plants is an enhanced rate of whole plant photosynthesis in a well irradiated canopy. Nevertheless, in some herbaceous species prolonged exposure to high CO_2 results in remobilization of nitrogenous reserves (i.e., leaf protein degradation) and reduced rates of mature leaf photosynthesis when assayed at ambient CO_2 and O_2 levels. Both short- and long-term exposures to those CO_2 levels (i.e., 100 to 2,000 mul.l^-1) which modify photosynthesis and export, also modify both endogenous ethylene gas (C_2H_4) release, and substrate, 1-aminocyclopropane-1-carboxylic acid (ACC), saturated C_2H_4 release rates from irradiated leaves. Photosynthetically active canopy leaves contribute most of the C_2H_4 released from the canopy. Prolonged growth at high CO_2 results in a persistent increase in the rate of endogenous C_2H_4 release from leaves which can, only in part, be attributed to the increase of the endogenous pools of C_2H_4 pathway intermediates (e.g., methionine, M-ACC, and ACC). The capacity for increasing the rate of C_2H_4 release in response to short-term exposures to varying CO_2 levels does not decline after prolonged growth at high CO_2. When leaves, whole plants, and model canopies of tomato plants are exposed to exogenous C_2H_4 a reduction in the rate of photosynthesis can, in each case, be attributed to the classical effects of C_2H_4 on plant development and morphology. The effect of C_2H_4 on CO_2 gas exchange of plant canopies is shown to be dependent on the canopy leaf area index.

  18. High-mobility group box 1 protein levels in serum of subjects after exposure to fire smoke--short communication.

    PubMed

    Krakowiak, Anna; Śliwkiewicz, Konrad; Nowakowska-Swirta, Ewa; Winnicka, Renata; Politański, Piotr

    2015-01-01

    Fire smoke inhalation a recognized etiologic factor of airway injuries. The objective of this study was evaluation of serum high-mobility group box 1 (HMGB1) protein concentration in subjects exposed to fire smoke (SEFS). The study group consisted of 40 consecutive patients admitted to the Toxicology Unit, Lodz, Poland after exposure to fire smoke. Serum HMGB1 concentrations were measured upon admission to hospital and rechecked on the 2nd and on the day of discharge. Patients also underwent routine toxicological diagnostic procedures applied in case of those exposures, such as carboxyhaemoglobin (COHb) levels and urinary thiocyanate concentrations. The same diagnostic tests were performed in 10 healthy volunteers not exposed to smoke of the control group. The average serum SEFS concentration of HMGB1 protein was not significantly higher on admission in comparison with the respective values recorded on the 2nd day and on the day of discharge. The mean serum level of HMGB1 protein of exposed group was higher than that one in the control group, however the difference was not statistically significant. The highest concentration of HMGB1 protein was noted in serum of 28 subjects exposed to fire smoke reporting at least one symptom and the difference was statistically significant in a comparison with the control group. As indicated, an acute exposure to smoke may lead to transient increase of HMGB1 in serum in exposed subjects. Further studies are necessary in order to confirm the importance of this protein in pathogenesis of acute airway injury due to exposure to fire smoke.

  19. Prenatal exposure to persistent organochlorine pollutants is associated with high insulin levels in 5-year-old girls

    PubMed Central

    Tang-Péronard, Jeanett L.; Heitmann, Berit L.; Jensen, Tina K.; Vinggaard, Anne Marie; Madsbad, Sten; Steuerwald, Ulrike; Grandjean, Philippe; Weihe, Pál; Nielsen, Flemming; Andersen, Helle R.

    2015-01-01

    Background Several persistent organochlorine pollutants (POPs) possess endocrine disrupting abilities, thereby potentially leading to an increased risk of obesity and metabolic diseases, especially if the exposure occurs during prenatal life. We have previously found associations between prenatal POP exposures and increased BMI, waist circumference and change in BMI from 5 to 7 years of age, though only among girls with overweight mothers. Objectives In the same birth cohort, we investigated whether prenatal POP exposure was associated with serum concentrations of insulin and leptin among 5-year-old children, thus possibly mediating the association with overweight and obesity at 7 years of age. Methods The analyses were based on a prospective Faroese Birth Cohort (n=656), recruited between 1997 and 2000. Major POPs, polychlorinated biphenyls (PCBs), p,p’-dichlorodiphenyldichloroethylene (DDE) and hexachlorobenzene (HCB), were measured in maternal pregnancy serum and breast milk. Children were followed-up at the age of 5 years where a non-fasting blood sample was drawn; 520 children (273 boys and 247 girls) had adequate serum amounts available for biomarker analyses by Luminex® technology. Insulin and leptin concentrations were transformed from continuous to binary variables, using the 75th percentile as a cut-off point. Multiple logistic regression was used to investigate associations between prenatal POP exposures and non-fasting serum concentrations of insulin and leptin at age 5 while taking into account confounders. Results Girls with highest prenatal POP exposure were more likely to have high non-fasting insulin levels (PCBs 4th quartile: OR=3.71; 95% CI: 1.36, 10.01. DDE 4th quartile: OR=2.75; 95% CI: 1.09, 6.90. HCB 4th quartile: OR=1.98; 95% CI: 1.06, 3.69) compared to girls in the lowest quartile. No significant associations were observed with leptin, or among boys. A mediating effect of insulin or leptin on later obesity was not observed. Conclusion

  20. Severe multisystem dysfunction in a case of high level exposure to smoked cannabis.

    PubMed

    Reece, Albert Stuart

    2009-01-01

    Cannabis use is common, controversial and its clinical toxicology is likely under-recognised. A 56-year-old man presented with disabling shortness of breath. He smoked up to 7 g cannabis daily for 25 years (maximum 63 875 g) plus large amounts of hashish oil. Chest x ray suggested giant bullae. CT of the chest revealed over 40 bullae, the largest being 11 cm in diameter. Osteoporosis with multiple vertebral crush fractures was noted on plain films and bone densitometry (t=-3.19). His dental health was poor. Hypertension, complicated by a large occipital stroke was shown by CT of the brain, and increased vascular age (69.8 years) found by pulse wave analysis. The case is significant as it indicates the potential severity of cannabis lung damage and suggests that significant cannabis exposure may cause osteoporosis and accelerated vascular ageing. The association of alveolar destruction, bone lysis and destruction of arterial elastic laminae suggest possible underlying mechanisms such as tissue proteinase activation, immunomodulation or stem cell impairment.

  1. High levels of indium exposure relate to progressive emphysematous changes: a 9-year longitudinal surveillance of indium workers.

    PubMed

    Amata, Atsuko; Chonan, Tatsuya; Omae, Kazuyuki; Nodera, Hiroshi; Terada, Jiro; Tatsumi, Koichiro

    2015-11-01

    During the last decade it has been clarified that the inhalation of indium compounds can evoke alveolar proteinosis, cholesterol granuloma, pulmonary fibrosis and emphysema. In this study, we aimed to elucidate the characteristics and time course of pulmonary disorders among indium workers using comprehensive pulmonary examinations at an indium-processing factory. Data for 84 male workers who underwent the examinations for nine consecutive years from 2002 to 2010 were analysed regarding their symptoms, serum indium concentration (sIn), serum markers of interstitial pneumonia, pulmonary function test parameters and high-resolution CT (HRCT) findings of the lungs. In association with improvements in the work environment and work practice, the sIn levels decreased with significant reductions in the KL-6 and surfactant protein D (SP-D) levels. Regarding the HRCT findings, the interstitial lesions regressed partially, whereas emphysematous lesions increased progressively in the workers with high sIn values. FEV1/FVC decreased with the years and the rate of decrease was significantly greater in those with high sIn. The biological half-life of sIn was estimated to be 8.09 years. The present findings suggest that the sIn, SP-D, KL-6 levels and radiological interstitial changes can be reduced in indium workers by alleviating exposure to indium, whereas emphysematous lesions can progress among those with a history of heavy exposure. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  2. Fetal exposure to high maternal thyroid hormone (TH) levels causes central resistance to TH in adult humans and mice.

    PubMed

    Srichomkwun, Panudda; Anselmo, João; Liao, Xiao-Hui; Hönes, G Sebastian; Moeller, Lars C; Alonso-Sampedro, Manuela; Weiss, Roy E; Dumitrescu, Alexandra M; Refetoff, Samuel

    2017-06-06

    Fetuses exposed to the high thyroid hormone (TH) levels of mothers with resistance to thyroid hormone beta (RTHβ), due to mutations in the THRB gene, have low birth weight and suppressed TSH. Determine if such exposure to high TH levels in embryonic life has a long-term effect into adulthood. Observations in humans with a parallel design on animals to obtain a preliminary information regarding mechanism. University research centers. Humans and mice with no RTHβ exposed during intrauterine life to high maternal TH levels from mothers who were, nevertheless, euthyroid due to RTHβ. Xοʋτρολσwere humans and mice of the same genotype but born to fathers with RTHβ αʋδμοτηερσwithout RTHβ and thus, with normal serum TH levels. TSH responses to stimulation with thyrotropin-releasing hormone (TRH) during adult life in humans and male mice before and after treatment with triiodothyronine (T3). Measurements of gene expression in anterior pituitaries, hypothalami and cerebral cortices of the mice. Adult humans and mice without RTHβ, exposed to high maternal TH in utero, showed persistent central resistance to TH as evidenced by reduced responses of serum TSH to TRH when treated with T3. In mice, anterior pituitary TSHβ and deiodinase 3 (D3) mRNAs, but not hypothalamic and cerebral cortex D3 were increased. Adult humans and mice without RTHβ exposed in-utero to high maternal TH levels, have persistent central resistance to TH. This is likely mediated by the increased expression of D3 in the anterior pituitary, enhancing local T3 degradation.

  3. The Effect of Exposure to High Noise Levels on the Performance and Rate of Error in Manual Activities

    PubMed Central

    Khajenasiri, Farahnaz; Zamanian, Alireza; Zamanian, Zahra

    2016-01-01

    Introduction Sound is among the significant environmental factors for people’s health, and it has an important role in both physical and psychological injuries, and it also affects individuals’ performance and productivity. The aim of this study was to determine the effect of exposure to high noise levels on the performance and rate of error in manual activities. Methods This was an interventional study conducted on 50 students at Shiraz University of Medical Sciences (25 males and 25 females) in which each person was considered as its own control to assess the effect of noise on her or his performance at the sound levels of 70, 90, and 110 dB by using two factors of physical features and the creation of different conditions of sound source as well as applying the Two-Arm coordination Test. The data were analyzed using SPSS version 16. Repeated measurements were used to compare the length of performance as well as the errors measured in the test. Results Based on the results, we found a direct and significant association between the levels of sound and the length of performance. Moreover, the participant’s performance was significantly different for different sound levels (at 110 dB as opposed to 70 and 90 dB, p < 0.05 and p < 0.001, respectively). Conclusion This study found that a sound level of 110 dB had an important effect on the individuals’ performances, i.e., the performances were decreased. PMID:27123216

  4. Effect of yogic exercises on thyroid function in subjects resident at sea level upon exposure to high altitude

    NASA Astrophysics Data System (ADS)

    Rawal, S. B.; Singh, M. V.; Tyagi, A. K.; Selvamurthy, W.; Chaudhuri, B. N.

    1994-03-01

    Using radioactive iodine, the effect of 1 month's yogic exercises has been investigated on the thyroid function of subjects resident at sea level (SL) specially after their exposure to high altitude (HA). The results have been compared with a group of SL subjects who underwent physical training (PT) exercises for the same duration. Ten healthy male volunteers in the age range of 20 30 years were used as test subjects in this study with each serving as his own control. The subjects were randomly divided into two groups of 5 each. One group practised hatha yogic exercises, while the other group performed the regular PT exercises. The thyroidal accumulation and release of radioactive iodine have been measured in each of the subjects of both groups before and after 1 month of their respective exercises at SL. One month of yogic exercises at SL has been observed to cause a significant reduction in the trans-thy-roidal availability of radioiodine. The thyroid radioactivity in this group of subjects was always below normal levels with the exception of two peaks of radioactive iodine uptake, when the levels of radioactivity in the thyroid were similar to the control values of pre-yogic exercises. The release of radiolabel at 24 48 h was significantly increased after yogic exercises. In contrast, the subjects performing PT exercises for the same duration at SL showed significant thyroid uptake of radioactive iodine at 24 h. Subsequently their131I uptake continued to rise slowly until 72 h without any demonstrable thyroidal release of radiolabel. This indicated that increased thyroid activity was induced by conventional PT exercise. Exposure of SL residents to HA irrespective of their exercise regime altered the thyroidal handling of radioiodine. Thyroidal concentrations of freshly administered radioiodine at early and late sampling intervals were very high in both of the groups, especially the yogics, after their return to SL from HA. Possible mechanisms of the observed

  5. Total effective dose equivalent assessment after exposure to high-level natural radiation using the RESRAD code.

    PubMed

    Ziajahromi, Shima; Khanizadeh, Meysam; Nejadkoorki, Farhad

    2014-03-01

    The current work reports the activity concentrations of several natural radionuclides ((226)Ra, (232)Th, and (40)K) in Khak-Sefid area of Ramsar, Iran. An evaluation of total effective dose equivalent (TEDE) from exposure to high-level natural radiations is also presented. Soil samples were analyzed using a high-purity germanium detector with 80 % relative efficiency. The TEDE was calculated on a land area of 40,000 m(2) with 1.5-m thickness of contaminated zone for the member of three critical groups of farmer, construction worker, and resident using Residual Radioactive Material Guidelines (RESRAD) modeling program. It was found that the mean activity concentrations (in Bq/kg) were 23,118 ± 468, 25.8 ± 2.3, and 402.6 ± 16.5 for (226)Ra, (232)Th, and (40)K, respectively. The maximum calculated TEDE during 1,000 years was 107.1 mSv/year at year 90, 92.42 mSv/year at year 88, and 22.09 mSv/year at year 46 for farmer, resident, and construction worker scenarios, respectively. The maximum TEDE in farmer scenario can be reduced to the level below the dose limit of 1 mSv/year which is safe for public health using soil cover with thickness of 50 cm or more on the contaminated zone. According to RESRAD prediction, the TEDE received by individuals for all exposure scenarios considerably exceed the set dose limit, and it is mainly due to (226)Ra.

  6. Effects of long-term exposure of tuffs to high-level nuclear waste repository conditions. Final report

    SciTech Connect

    Blacic, J.D.; Vaniman, D.T.; Bish, D.L.; Duffy, C.J.; Gooley, R.C.

    1986-08-01

    We have performed exploratory tests to investigate the effects of extended exposure of tuffs from Yucca Mountain, Nevada, to temperatures and pressures similar to those that will be encountered in a high-level nuclear waste repository. In a preliminary report we described statistically significant changes in strength properties and generally minor changes in porosity and grain density. In the present report we describe additional measurements that indicate possible changes in permeability (in one tuff type) after exposure for 2 to 6 months at temperatures from 80 to 180 C, confining pressures of 9.7 and 19.7 MPa, and water pore pressures of 0.5 and 19.7 MPa. Mineralogic examinations have established reactions involving dissolution of silica and feldspar minerals and possible conversion of clinoptilolite to mordenite. We conclude that rock properties important to the operation of a nuclear waste repository in tuff are likely to change over time when exposed to simulated repository conditions, and the details of these time-dependent processes should be investigated further.

  7. Exposures to high levels of carbon monoxide from wood-fired temazcal (steam bath) use in highland Guatemala.

    PubMed

    Thompson, Lisa M; Clark, Michael; Cadman, Brie; Canúz, Eduardo; Smith, Kirk R

    2011-01-01

    The temazcal is a wood-fired steam bath used in the rural highlands of Guatemala for bathing and healing. We measured carbon monoxide (CO) among 288 participants in 72 temazcales. Participants were drawn from communities who participated in the RESPIRE (Randomized Exposure Study of Pollution Indoors and Respiratory Effects) chimney stove intervention trial. Temazcal CO exposures were extremely high, averaging 431 parts per million (time-weighted average). Compared to kitchen wood-smoke exposures, the temazcal contributes significantly to weekly exposures, despite the fact that the population spends less time in the temazcal than in the kitchen. This report 1) describes temazcal use patterns; 2) reports participants' signs and symptoms during temazcal use; 3) models the distribution of temazcal CO concentrations; 4) assesses reliability of exhaled breath CO as a biomarker of CO exposure; and 5) provides a proportional analysis of CO concentrations from temazcal use, as compared to kitchen concentrations.

  8. Characterization of high-level daptomycin resistance in Viridans group Streptococci developed upon in vitro exposure to daptomycin.

    PubMed

    Akins, Ronda L; Katz, Bradley D; Monahan, Catherine; Alexander, Dylan

    2015-04-01

    Viridans group streptococci (VGS) are part of the normal flora that may cause bacteremia, often leading to endocarditis. We evaluated daptomycin against four clinical strains of VGS (MICs = 1 or 2 μg/ml) using an in vitro-simulated endocardial vegetation model, a simulated bacteremia model, and kill curves. Daptomycin exposure was simulated at 6 mg/kg of body weight and 8 mg/kg every 24 h for endocardial and bacteremia models. Total drug concentrations were used for analyses containing protein (albumin and pooled human serum), and free (unbound) drug concentrations (93% protein bound) were used for analyses not containing protein. Daptomycin MICs in the presence of protein were significantly higher than those in the absence of protein. Despite MICs below or at the susceptible breakpoint, all daptomycin regimens demonstrated limited kill in both pharmacodynamic models. A reduction of approximately 1 to 2 log10 CFU was seen for all isolates and dosages except daptomycin at 6 mg/kg, which achieved a reduction of 2.7 log10 CFU/g against one strain (Streptococcus gordonii 1649) in the endocardial model. Activity was similar in both pharmacodynamic models in the presence or absence of protein. Similar activity was noted in the kill curves over all multiples of the MIC. Regrowth by 24 h was seen even at 8× MIC. Postexposure daptomycin MICs for both pharmacodynamic models increased to >256 μg/ml for all isolates by 24 and 72 h. Despite susceptibility to daptomycin by standard MIC methods, these VGS developed high-level daptomycin resistance (HLDR) after a short duration following drug exposure not attributed to modification or inactivation of daptomycin. Further evaluation is warranted to determine the mechanism of resistance and clinical implications.

  9. Characterization of High-Level Daptomycin Resistance in Viridans Group Streptococci Developed upon In Vitro Exposure to Daptomycin

    PubMed Central

    Katz, Bradley D.; Monahan, Catherine; Alexander, Dylan

    2015-01-01

    Viridans group streptococci (VGS) are part of the normal flora that may cause bacteremia, often leading to endocarditis. We evaluated daptomycin against four clinical strains of VGS (MICs = 1 or 2 μg/ml) using an in vitro-simulated endocardial vegetation model, a simulated bacteremia model, and kill curves. Daptomycin exposure was simulated at 6 mg/kg of body weight and 8 mg/kg every 24 h for endocardial and bacteremia models. Total drug concentrations were used for analyses containing protein (albumin and pooled human serum), and free (unbound) drug concentrations (93% protein bound) were used for analyses not containing protein. Daptomycin MICs in the presence of protein were significantly higher than those in the absence of protein. Despite MICs below or at the susceptible breakpoint, all daptomycin regimens demonstrated limited kill in both pharmacodynamic models. A reduction of approximately 1 to 2 log10 CFU was seen for all isolates and dosages except daptomycin at 6 mg/kg, which achieved a reduction of 2.7 log10 CFU/g against one strain (Streptococcus gordonii 1649) in the endocardial model. Activity was similar in both pharmacodynamic models in the presence or absence of protein. Similar activity was noted in the kill curves over all multiples of the MIC. Regrowth by 24 h was seen even at 8× MIC. Postexposure daptomycin MICs for both pharmacodynamic models increased to >256 μg/ml for all isolates by 24 and 72 h. Despite susceptibility to daptomycin by standard MIC methods, these VGS developed high-level daptomycin resistance (HLDR) after a short duration following drug exposure not attributed to modification or inactivation of daptomycin. Further evaluation is warranted to determine the mechanism of resistance and clinical implications. PMID:25624330

  10. Occupational exposure to antineoplastic agents induces a high level of chromosome damage. Lack of an effect of GST polymorphisms

    SciTech Connect

    Testa, Antonella Giachelia, Manuela; Palma, Selena; Appolloni, Massimo; Padua, Luca; Tranfo, Giovanna; Spagnoli, Mariangela; Tirindelli, Donatella; Cozzi, Renata

    2007-08-15

    The aim of our study was to investigate whether occupational exposure to antineoplastic drugs (AND) resulted in genetic damage, possibly indicative of adverse health effects in the long term. We performed a chromosomal aberrations (CA) analysis in peripheral blood lymphocytes (PBL) of a group of 76 trained nurses occupationally exposed to AND. Furthermore, we analysed whether genetic polymorphisms in four metabolic genes of the glutathione S-transferase (GST) family involved in antineoplastic drugs detoxification (GSTM1, GSTT1, GSTP1, GSTA1) had any effect on the yield of chromosomal aberrations in nurses exposed to antineoplastic agents. The exposed group showed a very significant increase of genetic damage (p < 0.0001) potentially indicative of an increased risk of cancer. Unexpectedly, besides the elevated level of chromatid-type aberrations usually related to exposure to chemical agents, we found also severe chromosome damages such as chromosome deletions and dicentric chromosomes, usually related to radiation exposure. No significant association was detected between all GSTs genotypes and chromosome damage. In conclusion, our data show how the occupational exposure to AND is associated to a potential cancer risk, suggesting that current prevention methods do not completely eliminate opportunities for exposure and supporting the need to improve the actual safety practices.

  11. Examining exposure reciprocity in a resin based composite using high irradiance levels and real-time degree of conversion values.

    PubMed

    Selig, Daniela; Haenel, Thomas; Hausnerová, Berenika; Moeginger, Bernhard; Labrie, Daniel; Sullivan, Braden; Price, Richard B T

    2015-05-01

    Exposure reciprocity suggests that, as long as the same radiant exposure is delivered, different combinations of irradiance and exposure time will achieve the same degree of resin polymerization. This study examined the validity of exposure reciprocity using real time degree of conversion results from one commercial flowable dental resin. Additionally a new fitting function to describe the polymerization kinetics is proposed. A Plasma Arc Light Curing Unit (LCU) was used to deliver 0.75, 1.2, 1.5, 3.7 or 7.5 W/cm(2) to 2mm thick samples of Tetric EvoFlow (Ivoclar Vivadent). The irradiances and radiant exposures received by the resin were determined using an integrating sphere connected to a fiber-optic spectrometer. The degree of conversion (DC) was recorded at a rate of 8.5 measurements a second at the bottom of the resin using attenuated total reflectance Fourier Transform mid-infrared spectroscopy (FT-MIR). Five specimens were exposed at each irradiance level. The DC reached after 170s and after 5, 10 and 15 J/cm(2) had been delivered was compared using analysis of variance and Fisher's PLSD post hoc multiple comparison tests (alpha=0.05). The same DC values were not reached after the same radiant exposures of 5, 10 and 15 J/cm(2) had been delivered at an irradiance of 3.7 and 7.5 W/cm(2). Thus exposure reciprocity was not supported for Tetric EvoFlow (p<0.05). For Tetric EvoFlow, there was no significant difference in the DC when 5, 10 and 15J/cm(2) were delivered at irradiance levels of 0.75, 1.2 and 1.5 W/cm(2). The optimum combination of irradiance and exposure time for this commercial dental resin may be close to 1.5 W/cm(2) for 12s. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  12. Exposure to Hypoxia at High Altitude (5380 m) for 1 Year Induces Reversible Effects on Semen Quality and Serum Reproductive Hormone Levels in Young Male Adults.

    PubMed

    He, Jiang; Cui, Jianhua; Wang, Rui; Gao, Liang; Gao, Xiaokang; Yang, Liu; Zhang, Qiong; Cao, Jinjun; Yu, Wuzhong

    2015-09-01

    This study investigated the effect of hypoxia at high altitude on the semen quality and the serum reproductive hormone levels in male adults. A total of 52 male soldiers were enrolled in this cohort study. They were exposed to hypoxia at high altitude (5380 m) for 12 months when undergoing a service. After exposure, they were followed up for 6 months. The samples of semen and peripheral blood were collected at 1 month before exposure (M0), 6 months of exposure (M6), 12 months of exposure (M12), and 6 months after exposure (M18). The semen quality was assessed with computer-assisted analysis system, and the serum levels of reproductive hormones, including prolactin (PRL), luteinizing hormone (LH), follicle-stimulating hormone (FSH), and testosterone were analyzed by ELISA. Compared with those at M0, total sperm count, sperm density, motility, survival rate, and serum levels of LH, PRL and testosterone were significantly decreased, whereas the liquefaction time was significantly prolonged and serum FSH level was significantly increased at M6 (p<0.05). At M12, total sperm count and sperm density increased, whereas sperm motility, survival rate, and the liquefaction time further decreased. Sperm velocities, progression ratios, and lateral head displacements were also decreased. Serum FSH level decreased while serum LH, PRL, and testosterone levels increased. Compared with those at M6, the changes in these detected parameters of semen and hormone at M12 were significant (p<0.05). At M18, all these detected parameters except testosterone level returned to levels comparable to those before exposure. In conclusion, hypoxia at high altitude causes adverse effects on semen quality and reproductive hormones, and these effects are reversible.

  13. High altitude exposure alters gene expression levels of DNA repair enzymes, and modulates fatty acid metabolism by SIRT4 induction in human skeletal muscle.

    PubMed

    Acs, Zoltan; Bori, Zoltan; Takeda, Masaki; Osvath, Peter; Berkes, Istvan; Taylor, Albert W; Yang, Hu; Radak, Zsolt

    2014-06-01

    We hypothesized that high altitude exposure and physical activity associated with the attack to Mt Everest could alter mRNA levels of DNA repair and metabolic enzymes and cause oxidative stress-related challenges in human skeletal muscle. Therefore, we have tested eight male mountaineers (25-40 years old) before and after five weeks of exposure to high altitude, which included attacks to peaks above 8000m. Data gained from biopsy samples from vastus lateralis revealed increased mRNA levels of both cytosolic and mitochondrial superoxide dismutase. On the other hand 8-oxoguanine DNA glycosylase (OGG1) mRNA levels tended to decrease while Ku70 mRNA levels and SIRT6 decreased with altitude exposure. The levels of SIRT1 and SIRT3 mRNA did not change significantly. However, SIRT4 mRNA level increased significantly, which could indicate decreases in fatty acid metabolism, since SIRT4 is one of the important regulators of this process. Within the limitations of this human study, data suggest that combined effects of high altitude exposure and physical activity climbing to Mt. Everest, could jeopardize the integrity of the particular chromosome. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Discontinuity in the cancer slope factor as it passes from high to low exposure levels--arsenic in the BFD-endemic area.

    PubMed

    Lamm, Steven H; Robbins, Shayhan; Chen, Rusan; Lu, Jun; Goodrich, Brian; Feinleib, Manning

    2014-12-04

    The ingestion of inorganic arsenic causes bladder and lung cancers demonstrably at >400-500ug/L but questionably below 100-200ug/L. Using the standard 42-village cancer mortality dataset from the Blackfoot-disease (BFD) endemic area of southwest Taiwan (Wu et al., 1989), we examined the risk from low exposures by excluding the high exposures. Poisson regression analyses with the sequential removal of the highest exposure village have been performed using the median, mean, or maximum village well water arsenic level and demonstrated graphically. Risk estimates are positive when villages with exposures of 200-400ug/L are included and significantly so when villages with >400ug/L are included. Risk estimates for exposures below 100ug/L are negative but rarely significantly so. The inflection point where the slope is no longer positive occurs in the range of 100-200ug/L, depending upon whether the exposure metric used is the median, the mean or the maximum. There is a discontinuity in the cancer slope factor or risk from arsenic exposure that occurs in the range of 100-200ug/L. Above these levels, there are significantly positive risks, while below these levels there are not. The analysis reveals within this dataset an intrinsic non-linearity in the cancer risk. The literature speaks to this discontinuity, but this is the first demonstration within a single dataset that shows the discontinuity across the full exposure range and where the low-dose data are not compromised with high-dose data. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  15. Exposure-based Interventions for the management of individuals with high levels of needle fear across the lifespan: a clinical practice guideline and call for further research

    PubMed Central

    McMurtry, C. Meghan; Taddio, Anna; Noel, Melanie; Antony, Martin M.; Chambers, Christine T.; Asmundson, Gordon J. G.; Pillai Riddell, Rebecca; Shah, Vibhuti; MacDonald, Noni E.; Rogers, Jess; Bucci, Lucie M.; Mousmanis, Patricia; Lang, Eddy; Halperin, Scott; Bowles, Susan; Halpert, Christine; Ipp, Moshe; Rieder, Michael J.; Robson, Kate; Uleryk, Elizabeth; Votta Bleeker, Elizabeth; Dubey, Vinita; Hanrahan, Anita; Lockett, Donna; Scott, Jeffrey

    2016-01-01

    Abstract Needle fear typically begins in childhood and represents an important health-related issue across the lifespan. Individuals who are highly fearful of needles frequently avoid health care. Although guidance exists for managing needle pain and fear during procedures, the most highly fearful may refuse or abstain from such procedures. The purpose of a clinical practice guideline (CPG) is to provide actionable instruction on the management of a particular health concern; this guidance emerges from a systematic process. Using evidence from a rigorous systematic review interpreted by an expert panel, this CPG provides recommendations on exposure-based interventions for high levels of needle fear in children and adults. The AGREE-II, GRADE, and Cochrane methodologies were used. Exposure-based interventions were included. The included evidence was very low quality on average. Strong recommendations include the following. In vivo (live/in person) exposure-based therapy is recommended (vs. no treatment) for children seven years and older and adults with high levels of needle fear. Non-in vivo (imaginal, computer-based) exposure (vs. no treatment) is recommended for individuals (over seven years of age) who are unwilling to undergo in vivo exposure. Although there were no included trials which examined children < 7 years, exposure-based interventions are discussed as good clinical practice. Implementation considerations are discussed and clinical tools are provided. Utilization of these recommended practices may lead to improved health outcomes due to better health care compliance. Research on the understanding and treatment of high levels of needle fear is urgently needed; specific recommendations are provided. PMID:27007463

  16. Exposure-based Interventions for the management of individuals with high levels of needle fear across the lifespan: a clinical practice guideline and call for further research.

    PubMed

    McMurtry, C Meghan; Taddio, Anna; Noel, Melanie; Antony, Martin M; Chambers, Christine T; Asmundson, Gordon J G; Pillai Riddell, Rebecca; Shah, Vibhuti; MacDonald, Noni E; Rogers, Jess; Bucci, Lucie M; Mousmanis, Patricia; Lang, Eddy; Halperin, Scott; Bowles, Susan; Halpert, Christine; Ipp, Moshe; Rieder, Michael J; Robson, Kate; Uleryk, Elizabeth; Votta Bleeker, Elizabeth; Dubey, Vinita; Hanrahan, Anita; Lockett, Donna; Scott, Jeffrey

    2016-04-01

    Needle fear typically begins in childhood and represents an important health-related issue across the lifespan. Individuals who are highly fearful of needles frequently avoid health care. Although guidance exists for managing needle pain and fear during procedures, the most highly fearful may refuse or abstain from such procedures. The purpose of a clinical practice guideline (CPG) is to provide actionable instruction on the management of a particular health concern; this guidance emerges from a systematic process. Using evidence from a rigorous systematic review interpreted by an expert panel, this CPG provides recommendations on exposure-based interventions for high levels of needle fear in children and adults. The AGREE-II, GRADE, and Cochrane methodologies were used. Exposure-based interventions were included. The included evidence was very low quality on average. Strong recommendations include the following. In vivo (live/in person) exposure-based therapy is recommended (vs. no treatment) for children seven years and older and adults with high levels of needle fear. Non-in vivo (imaginal, computer-based) exposure (vs. no treatment) is recommended for individuals (over seven years of age) who are unwilling to undergo in vivo exposure. Although there were no included trials which examined children < 7 years, exposure-based interventions are discussed as good clinical practice. Implementation considerations are discussed and clinical tools are provided. Utilization of these recommended practices may lead to improved health outcomes due to better health care compliance. Research on the understanding and treatment of high levels of needle fear is urgently needed; specific recommendations are provided.

  17. Effect of Short-Term Exposure to High Particulate Levels on Cough Reflex Sensitivity in Healthy Tourists: A Pilot Study

    PubMed Central

    Sato, Ryuhei; Gui, Peijun; Ito, Kumiko; Kohzuki, Masahiro; Ebihara, Satoru

    2016-01-01

    Background: Previous studies have reported a relationship between particulate air pollution and respiratory symptoms or decline in lung function, but information about acute effects of short-term exposure to airborne particulate matter (PM) on cough and pulmonary function is scarce. Objective: To investigate the effect of short-term exposure to high concentrations of PM on the cough reflex threshold, urge-to-cough, pulmonary function, and cough-related quality of life in a group of healthy non-resident volunteers visiting Beijing, China. Methods: Seventeen healthy residents of Sendai, Japan, who planned to attend a meeting in Beijing, were recruited. We checked local air quality and measured cough reflex thresholds, urge-to-cough, pulmonary function, and Leicester Cough Questionnaire-acute (LCQ-acute) scores in the volunteers before, during, and after their trip to Beijing. Results: The PM2.5 and PM10 concentrations in Beijing were significantly higher than those in Japan on the measurement days. Cough reflex thresholds, expressed as nebulized citric acid concentrations required to induce ≥ 2 and ≥ 5 coughs, were significantly lower during the stay in Beijing than before or after the visit. Vital capacity, forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and FEV1/FVC were significantly lower during the stay in Beijing than before the trip. Similarly, the urge-to-cough threshold was significantly lower during the stay in Beijing than after the trip, as was the total LCQ-acute score. Conclusion: We tentatively concluded that short-term exposure to high PM concentrations may have adverse effects on cough reflex and urge-to-cough thresholds, pulmonary function, and cough-related quality of life. PMID:28217195

  18. High Levels of Bisphenol A and Bisphenol S in Brazilian Thermal Paper Receipts and Estimation of Daily Exposure.

    PubMed

    Rocha, Bruno Alves; Azevedo, Lara Ferreira; Gallimberti, Matheus; Campiglia, Andres Dobal; Barbosa, Fernando

    2015-01-01

    Bisphenol A (BPA) is an endocrine and metabolic disruptor commonly employed as a color developer in thermal papers. Consequently, BPA derived from thermal papers has been considered an important source of exposure for humans, since this chemical may migrate from paper to skin upon contact. Further, due to recent restrictions on BPA use in some countries, it has been replaced by a new analogue, bisphenol S (BPS). The aim of the present study was to determine levels of BPA and BPS in 190 different thermal receipts, randomly collected from different locations in São Paulo State, Brazil, including receipts from supermarkets, general and fast-food restaurants, gas stations, bus and airplane tickets, and credit card and bank accounts. BPA and/or BPS were detected in 98% of samples at concentrations ranging from below the quantification limit to 4.3% (mg/100 mg paper). The obtained values were higher than amounts previously reported in other countries. The estimated daily intake through dermal absorption from handling of thermal receipt papers was estimated on the basis of concentrations and frequencies of handling of papers by humans in both the general population and occupationally exposed individuals. Fifth percentile, median, and 95th percentile daily intakes by the general population were 0.44, 1.42, and 2 μg/d, respectively, whereas the corresponding values for occupationally exposed population are 21.8, 71 and 101 μg/d. The potential adverse consequences of elevated occupational exposure are currently being examined.

  19. High Exposure Facility Technical Description

    SciTech Connect

    Carter, Gregory L.; Stithem, Arthur R.; Murphy, Mark K.; Smith, Alex K.

    2008-02-12

    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."

  20. High-throughput PBPK and Microdosimetry: Cell-level Exposures in a Virtual Tissue Context (WC9)

    EPA Science Inventory

    Toxicokinetic (TK) models can determine whether chemical exposures produce potentially hazardous tissue concentrations. Tissue microdosimetry TK models relate whole-body chemical exposures to cell-scale concentrations. As a proof of concept, we approximated the micro-anatomic arc...

  1. High-throughput PBPK and Microdosimetry: Cell-level Exposures in a Virtual Tissue Context (WC9)

    EPA Science Inventory

    Toxicokinetic (TK) models can determine whether chemical exposures produce potentially hazardous tissue concentrations. Tissue microdosimetry TK models relate whole-body chemical exposures to cell-scale concentrations. As a proof of concept, we approximated the micro-anatomic arc...

  2. Permissible exposure levels and emergency exposure guidance levels for selected airborne contaminants. Final report

    SciTech Connect

    Not Available

    1991-01-01

    The U.S. Navy requested that the National Research Council's Committee on Toxicology recommend permissible exposure levels (PELs) for zinc dimethyldithiocarbamate (ziram) and ethylhexyl nitrate. No exposure levels for these compounds have been recommended either by the Occupational Safety and Health Administration or by the American Conference of Governmental Industrial Hygienists. The U.S. Army's Surgeon General's office also requested the 2-min emergency exposure guidance levels (EEGLs) for hydrogen chloride because of the Army's concern for the short-term high-level exposure of soldiers to hydrogen chloride vapors released during firing of various rocket motors and missiles. In response to these requests, the Committee on Toxicology set up the Subcommittee on Permissible Exposure Levels. The subcommittee, whose expertise is in toxicology, inhalation toxicology, genetics, biostatistics, medicine, and pathology, evaluated the toxicity data on ziram, ethylhexyl nitrate, and hydrogen chloride. In addition to the recommendations for PELs for ziram and ethylhexyl nitrate and EEGLs for hydrogen chloride, the subcommittee has identified deficiencies in the data and made recommendations for additional research. The subcommittee believes that the recommended exposure levels will provide adequate protection for workers and soldiers from these chemicals.

  3. Prolonged exposure to high and variable phenylalanine levels over the lifetime predicts brain white matter integrity in children with phenylketonuria.

    PubMed

    Hood, Anna; Antenor-Dorsey, Jo Ann V; Rutlin, Jerrel; Hershey, Tamara; Shimony, Joshua S; McKinstry, Robert C; Grange, Dorothy K; Christ, Shawn E; Steiner, Robert; White, Desiree A

    2015-01-01

    In this study, we retrospectively examined the microstructural white matter integrity of children with early- and continuously-treated PKU (N=36) in relation to multiple indices of phenylalanine (Phe) control over the lifetime. White matter integrity was assessed using mean diffusivity (MD) from diffusion tensor imaging (DTI). Eight lifetime indices of Phe control were computed to reflect average Phe (mean, index of dietary control), variability in Phe (standard deviation, standard error of estimate, % spikes), change in Phe with age (slope), and prolonged exposure to Phe (mean exposure, standard deviation exposure). Of these indices, mean Phe, mean exposure, and standard deviation exposure were the most powerful predictors of widespread microstructural white matter integrity compromise. Findings from the two previously unexamined exposure indices reflected the accumulative effects of elevations and variability in Phe. Given that prolonged exposure to elevated and variable Phe was particularly detrimental to white matter integrity, Phe should be carefully monitored and controlled throughout childhood, without liberalization of Phe control as children with PKU age.

  4. Exposure levels and determinants of inhalable dust exposure in bakeries.

    PubMed

    Burstyn, I; Teschke, K; Kennedy, S M

    1997-12-01

    The study's objectives were to measure full-shift exposure to inhalable dust in bakeries and define the determinants of full-shift exposure. Inhalable dust was measured gravimetrically. Ninety-six bakery workers, employed in seven different bakeries, participated in the study. Two side-by-side full-shift inhalable dust samples were obtained from each study participant on a single occasion. Samples were collected on 18 days selected at random. During the entire sampling period, bakers were observed and information on 14 different tasks was recorded at 15 min intervals. Other production characteristics were also recorded for each sampling day. These task and production variables were used in statistical modelling to identify significant predictors of exposure. The mean full-shift inhalable dust exposure was 8.2 mg/m3 (range: 0.1-110 mg/m3). A regression model explained 79% of the variability in exposure. The model indicated that tasks such as weighing, pouring and operating dough-brakers and reversible sheeters increased the exposure, while packing, catching and decorating decreased the exposure. Bread and bun production lines were associated with increased full-shift inhalable dust exposure, while cake production and substitution of dusting with the use of divider oil were associated with decreased exposure. Production tasks and characteristics are strong predictors of personal full-shift exposures to flour dust among bakers; these can be altered to reduce exposure levels.

  5. Health effects of high level exposure to traditional pollutants in East Germany--review and ongoing research

    SciTech Connect

    Wichmann, H.E. |; Heinrich, J.

    1995-03-01

    In East Germany ambient air pollution is characterized by high concentrations of sulfur dioxide (SO{sub 2}) and suspended particulates (SP). Since acidity and sulfate are surprisingly low, oxidation of SO{sub 2} seems to be incomplete and neutralization seems to play an important role. Few studies on health effects of air pollution in the former German Democratic Republic have been performed. They showed an increased prevalence in polluted areas of respiratory symptoms, lung function decrement, mild anemia, nonspecific stimulation of the immune system and, retardation of skeletal maturation of children. Since the German unification in 1990, several large-scale studies have been started. Short-term effects of air pollution on daily mortality have been investigated in Erfurt retrospectively for 1980 to 1989. Logarithmic exposure-effect curves have been found for both SO{sub 2} and SP. The number of deaths increased by about 10% with SO{sub 2} and by more than 20% with SP if the 95th percentile of the pollutant is compared to the 5th percentile. The logarithmic shape shows that the increase of ambient concentrations at the beginning of the heating season in fall is more important than further increases in concentrations later in winter. A second study on short-term effects was conducted using daily peak flow measurements and respiratory symptoms in 270 patients with asthma and other obstructive airway diseases in East Germany and the Czech Republic between 1990 and 1992. From regression analysis it follows that an increase by 500 {mu}g/m{sup 3} of SO{sub 2} leads to a mean decrease of the average patient`s peak flow below 2%. Three cross-sectional studies are in progress to compare the existing respiratory health status in East and West Germany. They consider about 9000 adults (20-44 years of age), 9000 school children (9-11 years of age) and 10,000 preschool children (age 6). Analysis is ongoing. 40 refs., 4 figs., 6 tabs.

  6. Violent Youths' Responses to High Levels of Exposure to Community Violence: What Violent Events Reveal about Youth Violence

    ERIC Educational Resources Information Center

    Wilkinson, Deanna L.; Carr, Patrick J.

    2008-01-01

    Recent work on the relationship between adolescent violence and its outcomes has posited that aggression by adolescents who are exposed to violence can be viewed as an adaptive strategy that seeks to order dangerous and unpredictable environments. Using reports from 416 active violent youth, we analyze lifetime exposure to community violence and…

  7. Exposure to High or Low Glucose Levels Accelerates the Appearance of Markers of Endothelial Cell Senescence and Induces Dysregulation of Nitric Oxide Synthase

    PubMed Central

    2013-01-01

    To test the hypothesis that aging impairs endothelial cell response to glucose stress, we utilized a human umbilical vein endothelial cell in vitro model in which clinically relevant concentrations of normal (5.5mM), high (25mM), and low (1.5mM) glucose were tested. With advancing population doubling, exposure to normal glucose gradually decreased endothelial nitric oxide synthase expression and activity, resulting in slow, progressive development of markers of cell senescence (by population doubling level [PDL] 44). High or low glucose treatment accelerated the appearance of markers of senescence (by ~PDL 35) along with declines in endothelial nitric oxide synthase expression and activity. Human umbilical vein endothelial cells exposed to alternating low and high glucose gave even more rapid acceleration in the appearance of markers of senescence (by ~PDL 18) and reduction in endothelial nitric oxide synthase levels. Thus, exposure to low and high glucose induces earlier appearance of markers of endothelial cell senescence and dysregulation of the nitric oxide synthase gene and protein expression and function. These findings will help to elucidate endothelial dysfunction associated with glucose intolerance and improve future therapy for diabetic seniors. PMID:23585419

  8. Long-term exposure to high-altitude chronic hypoxia during gestation induces neonatal pulmonary hypertension at sea level

    PubMed Central

    Herrera, Emilio A.; Riquelme, Raquel A.; Ebensperger, Germán; Reyes, Roberto V.; Ulloa, César E.; Cabello, Gertrudis; Krause, Bernardo J.; Parer, Julian T.; Giussani, Dino A.

    2010-01-01

    We determined whether postnatal pulmonary hypertension induced by 70% of pregnancy at high altitude (HA) persists once the offspring return to sea level and investigated pulmonary vascular mechanisms operating under these circumstances. Pregnant ewes were divided into two groups: conception, pregnancy, and delivery at low altitude (580 m, LLL) and conception at low altitude, pregnancy at HA (3,600 m) from 30% of gestation until delivery, and return to lowland (LHL). Pulmonary arterial pressure (PAP) was measured in vivo. Vascular reactivity and morphometry were assessed in small pulmonary arteries (SPA). Protein expression of vascular mediators was determined. LHL lambs had higher basal PAP and a greater increment in PAP after NG-nitro-l-arginine methyl ester (20.9 ± 1.1 vs. 13.7 ± 0.5 mmHg; 39.9 ± 5.0 vs. 18.3 ± 1.3 mmHg, respectively). SPA from LHL had a greater maximal contraction to K+ (1.34 ± 0.05 vs. 1.16 ± 0.05 N/m), higher sensitivity to endothelin-1 and nitroprusside, and persistence of dilatation following blockade of soluble guanylate cyclase. The heart ratio of the right ventricle-to-left ventricle plus septum was higher in the LHL relative to LLL. The muscle area of SPA (29.3 ± 2.9 vs. 21.1 ± 1.7%) and the protein expression of endothelial nitric oxide synthase (1.7 ± 0.1 vs. 1.1 ± 0.2), phosphodiesterase (1.4 ± 0.1 vs. 0.7 ± 0.1), and Ca2+-activated K+ channel (0.76 ± 0.16 vs. 0.30 ± 0.01) were greater in LHL compared with LLL lambs. In contrast, LHL had decreased heme oxygenase-1 expression (0.82 ± 0.26 vs. 2.22 ± 0.44) and carbon monoxide production (all P < 0.05). Postnatal pulmonary hypertension induced by 70% of pregnancy at HA promotes cardiopulmonary remodeling that persists at sea level. PMID:20881096

  9. Assessment of arsenic levels in body samples and chronic exposure in people using water with a high concentration of arsenic: a field study in Kutahya.

    PubMed

    Arikan, Inci; Namdar, Nazli Dizen; Kahraman, Cuneyt; Dagci, Merve; Ece, Ezgi

    2015-01-01

    This study aimed to evaluate the prevalence of skin lesions, which is a health effect of chronic arsenic (As) exposure, and determine the hair/blood arsenic concentrations of people living in Kutahya villages who are using and drinking tap water with a high concentration of arsenic. A total of 303 people were included in the present cross-sectional study. A prepared questionnaire form was used to collect the participants' information and environmental history. Skin examination was performed on all participants. Hair, blood and water samples were analyzed using atomic absorption spectroscopy. The cumulative arsenic index (CAI) was calculated for all participants. Villages were divided into two groups according to the arsenic level (<20 μg/L, Group I; >20 μg/L, Group II) in their water. The prevalence of skin lesions, hair and blood arsenic level, and CAI were found to be higher in the Group II participants. There was a positive association between body arsenic levels and CAI in the participants of each group. The number of skin lesions and arsenic concentrations in body samples were found to increase with the water arsenic level and exposure time. We hope that sharing this study's results with local administrators will help accelerate the rehabilitation of water sources in Kutahya.

  10. Acute and chronic exposure to high levels of glucose modulates tight junction-associated epithelial barrier function in a renal tubular cell line.

    PubMed

    Mongelli-Sabino, B M; Canuto, L P; Collares-Buzato, C B

    2017-11-01

    Type 2 diabetes mellitus (T2DM) is one of the most prevalent diseases worldwide. Diabetic nephropathy (DN) is a complication of diabetes and the mechanisms underlying onset and progression of this disease are not fully understood. It has been shown that hyperglycemia is an independent factor to predict the development of DN in individuals with T2DM, however, a link between high plasma glucose levels and renal tubular injuries in DN remains unknown. In this study, we investigated the effect of high levels of glucose (i.e. 180 or 360mg/dL) for up to 24h (acute) or over 72h (chronic) upon tight junction (TJ)-mediated epithelial barrier integrity of the kidney tubular cell line, MDCK. High levels of glucose (180 and 360mg/dL) induced a decrease in transepithelial electrical resistance associated with an increase in TJ cation selectivity at 24h or in TJ permeability to a paracellular marker, Lucifer Yellow, at 72h-exposure when compared to control group (exposed to 100mg/dL glucose). Immunofluorescence analyses showed that glucose treatment induced a significant decrease in the tight junctional content of claudins-1 and -3 as well as a significant increase in claudin-2 (particularly at 24h-exposure) and a time-dependent change in occludin/ZO-1 junctional content. The analyses of total cell content of these junctional proteins by Western blot did not reveal significant changes, except in claudin-2 expression. Our data suggest that high levels of glucose induce time-dependence changes in TJ structure in MDCK monolayers, suggesting a possible link between hyperglycemia-induced tubular epithelial barrier disruption and diabetic nephropathy. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Pharyngeal pumping inhibition and avoidance by acute exposure to high CO2 levels are both regulated by the BAG neurons via different molecular pathways.

    PubMed

    Sharabi, Kfir; Charar, Chayki; Gruenbaum, Yosef

    2015-01-01

    Carbon dioxide (CO2) is a key molecule in many biological processes. Studies in humans, mice, D. melanogaster, C. elegans, unicellular organisms and plants have shed light on the molecular pathways activated by elevated levels of CO2. However, the mechanisms that organisms use to sense and respond to high CO2 levels remain largely unknown. Previous work has shown that C. elegans quickly avoid elevated CO2 levels using mechanisms that involve the BAG, ASE and AFD neurons via cGMP- and calcium- signaling pathways. Here, we discuss our recent finding that exposure of C. elegans to high CO2 levels leads to a very rapid cessation in the contraction of the pharynx muscles. Surprisingly, none of the tested CO2 avoidance mutants affected the rapid pumping inhibition response to elevated CO2 levels. A forward genetic screen identified that the hid-1-mediated pathway of dense core vesicle maturation regulates the pumping inhibition, probably through affecting neuropeptide secretion. Genetic studies and laser ablation experiments showed that the CO2 response of the pharyngeal muscle pumping is regulated by the BAG neurons, the same neurons that mediate CO2 avoidance.

  12. Biological effects of short, high-level exposure to gases: ammonia, carbon monoxide, sulfur dioxide, and nitrogen oxides. Final summary report, 1 June 1979-15 August 1980

    SciTech Connect

    Legters, L.; Nightingale, T.E.; Normandy, M.J.; Morton, J.D.

    1980-06-01

    This project addressed the exposure of soldiers to toxic gases for periods of less than one hour and at concentrations above occupational exposure standards, with repetition up to six times per day for 14 days. Sources of the four gases are primarily propellant fumes and engine exhaust. Measurements have shown physiologically significant exposures to carbon monoxide and ammonia. Literature reviews and critical evaluations developed acceptable data bases on the types of biologic effects to be expected and on quantitative relationships between exposure level and intensity of response. These were interpreted in the context of the military exposure scenario and exposure criteria were suggested. Information gaps were identified and suggestions were made for further research. (Author)

  13. Is There a Safe Level of Exposure to a Carcinogen?

    ERIC Educational Resources Information Center

    Hrudey, Steve E.; Krewski, Daniel

    1995-01-01

    Presents an approach to estimating the "safe" levels of low-dose exposure to carcinogens that involves working upward from the smallest conceivable chronic dose instead of extrapolating downward from high exposures. Discusses expert and public opinion and other issues related to quantitative cancer risk assessment. (LZ)

  14. Is There a Safe Level of Exposure to a Carcinogen?

    ERIC Educational Resources Information Center

    Hrudey, Steve E.; Krewski, Daniel

    1995-01-01

    Presents an approach to estimating the "safe" levels of low-dose exposure to carcinogens that involves working upward from the smallest conceivable chronic dose instead of extrapolating downward from high exposures. Discusses expert and public opinion and other issues related to quantitative cancer risk assessment. (LZ)

  15. Discharge behaviors of trapezius motor units during exposure to low and high levels of acute psychosocial stress

    PubMed Central

    Stephenson, Jennifer L; Maluf, Katrina S

    2010-01-01

    This study investigated the effects of acute psychosocial stress on trapezius single motor unit discharge behaviors. Twenty-one healthy women performed feedback-controlled isometric contractions under conditions of low and high psychosocial stress in the same experimental session. Psychosocial stress was manipulated using a verbal math task combined with social evaluative threat which significantly increased perceived anxiety, heart rate, and blood pressure (P<0.001). Motor unit discharge behaviors including the threshold and discharge rate at recruitment (7.7 (5.7) %MVC and 7.3 (6.8) pps, P>0.121, N=103) and derecruitment (6.0(4.4) %MVC and 6.5(4.1) pps, P>0.223, N=99), the mean (11.3 (2.3) pps, P=0.309, N=106) and variability (2.5 (0.91) pps, P=0.958, N=106) of discharge rate, and the proportion of motor units exhibiting double discharges (21%, P=0.446) did not change across stress conditions. Discharge rate modulation with changes in contraction intensity was highly variable and similar across stress conditions (P>0.308, N=89). Rate-rate modulation of concurrently active motor units was also highly variable (r=−0.84–1.00, N=75). Estimates of ΔF for motor unit pairs with rate-rate modulation ≥0.7 were positive and similar across stress conditions (4.7(2.0) pps, P=0.405, N=16). Results indicate that acute psychosocial stress does not alter trapezius motor unit discharge behaviors during a precisely controlled motor task in healthy women. PMID:20087201

  16. Early In Vitro and In Vivo Development of High-Level Daptomycin Resistance Is Common in Mitis Group Streptococci after Exposure to Daptomycin

    PubMed Central

    García-de-la-Mària, Cristina; Pericas, Juan M.; del Río, Ana; Castañeda, Ximena; Vila-Farrés, Xavier; Armero, Yolanda; Espinal, Paula A.; Cervera, Carlos; Soy, Dolors; Falces, Carlos; Ninot, Salvador; Almela, Manel; Mestres, Carlos A.; Gatell, Jose M.; Vila, Jordi; Moreno, Asuncion; Marco, Francesc

    2013-01-01

    The development of high-level daptomycin resistance (HLDR; MIC of ≥256 mg/liter) after exposure to daptomycin has recently been reported in viridans group streptococcus (VGS) isolates. Our study objectives were as follows: to know whether in vitro development of HLDR after exposure to daptomycin was common among clinical isolates of VGS and Streptococcus bovis; to determine whether HLDR also developed during the administration of daptomycin to treat experimental endocarditis caused by the daptomycin-susceptible, penicillin-resistant Streptococcus mitis strain S. mitis 351; and to establish whether combination with gentamicin prevented the development of HLDR in vitro and in vivo. In vitro studies were performed with 114 VGS strains (mitis group, 92; anginosus group, 10; mutans group, 8; and salivarius group, 4) and 54 Streptococcus bovis strains isolated from 168 consecutive patients with infective endocarditis diagnosed between 1995 and 2010. HLDR was only observed after 24 h of exposure to daptomycin in 27% of the mitis group, including 27% of S. mitis isolates, 47% of S. oralis isolates, and 13% of S. sanguis isolates. In our experimental model, HLDR was detected in 7/11 (63%) and 8/12 (67%) isolates recovered from vegetations after 48 h of daptomycin administered at 6 mg/kg of body weight/24 h and 10 mg/kg/24 h, respectively. In vitro, time-kill experiments showed that daptomycin plus gentamicin was bactericidal against S. mitis 351 at tested concentrations of 0.5 and 1 times the MIC and prevented the development of HLDR. In vivo, the addition of gentamicin at 1 mg/kg/8 h to both daptomycin arms prevented HLDR in 21 out of 23 (91%) rabbits. Daptomycin plus gentamicin was at least as effective as vancomycin plus gentamicin. In conclusion, HLDR develops rapidly and frequently in vitro and in vivo among mitis group streptococci. Combining daptomycin with gentamicin enhanced its activity and prevented the development of HLDR in most cases. PMID:23478959

  17. Acute high-level exposure to WTC particles alters expression of genes associated with oxidative stress and immune function in the lung.

    PubMed

    Cohen, Mitchell D; Vaughan, Joshua M; Garrett, Brittany; Prophete, Colette; Horton, Lori; Sisco, Maureen; Kodavanti, Urmila P; Ward, William O; Peltier, Richard E; Zelikoff, Judith; Chen, Lung-chi

    2015-01-01

    First responders (FR) present at Ground Zero in the first 72 h after the World Trade Center (WTC) collapsed have progressively exhibited significant respiratory injuries. The few toxicology studies performed to date evaluated effects from just fine (< 2.5 µm) WTC dusts; none examined health effects/toxicities from atmospheres bearing larger particle sizes, despite the fact the majority (> 96%) of dusts were > 10 µm and most FR likely entrained dusts by mouth breathing. Using a system that generated/delivered supercoarse (10-53 µm) WTC dusts to F344 rats (in a manner that mimicked FR exposures), this study sought to examine potential toxicities in the lungs. In this exploratory study, rats were exposed for 2 h to 100 mg WTC dust/m(3) (while under isoflurane [ISO] anesthesia) or an air/ISO mixture; this dose conservatively modeled likely exposures by mouth-breathing FR facing ≈750-1000 mg WTC dust/m(3). Lungs were harvested 2 h post-exposure and total RNA extracted for subsequent global gene expression analysis. Among the >  1000 genes affected by WTC dust (under ISO) or ISO alone, 166 were unique to the dust exposure. In many instances, genes maximally-induced by the WTC dust exposure (relative to in naïve rats) were unchanged/inhibited by ISO only; similarly, several genes maximally inhibited in WTC dust rats were largely induced/unchanged in rats that received ISO only. These outcomes reflect likely contrasting effects of ISO and the WTC dust on lung gene expression. Overall, the data show that lungs of rats exposed to WTC dust (under ISO) - after accounting for any impact from ISO alone - displayed increased expression of genes related to lung inflammation, oxidative stress, and cell cycle control, while several involved in anti-oxidant function were inhibited. These changes suggested acute inflammogenic effects and oxidative stress in the lungs of WTC dust-exposed rats. This study, thus, concludes that a single very high exposure

  18. Acute high-level exposure to WTC particles alters expression of genes associated with oxidative stress and immune function in the lung

    PubMed Central

    Cohen, Mitchell D.; Vaughan, Joshua M.; Garrett, Brittany; Prophete, Colette; Horton, Lori; Sisco, Maureen; Kodavanti, Urmila P.; Ward, William O.; Peltier, Richard E.; Zelikoff, Judith; Chen, Lung-chi

    2015-01-01

    First responders (FR) present at Ground Zero in the first 72 h after the World Trade Center (WTC) collapsed have progressively exhibited significant respiratory injuries. The few toxicology studies performed to date evaluated effects from just fine (<2.5 µm) WTC dusts; none examined health effects/toxicities from atmospheres bearing larger particle sizes, despite the fact the majority (496%) of dusts were >10µm and most FR likely entrained dusts by mouth breathing. Using a system that generated/delivered supercoarse (10–53 µm) WTC dusts to F344 rats (in a manner that mimicked FR exposures), this study sought to examine potential toxicities in the lungs. In this exploratory study, rats were exposed for 2 h to 100 mg WTC dust/m3 (while under isoflurane [ISO] anesthesia) or an air/ISO mixture; this dose conservatively modeled likely exposures by mouth-breathing FR facing ≈750–1000 mg WTC dust/m3. Lungs were harvested 2 h post-exposure and total RNA extracted for subsequent global gene expression analysis. Among the > 1000 genes affected by WTC dust (under ISO) or ISO alone, 166 were unique to the dust exposure. In many instances, genes maximally-induced by the WTC dust exposure (relative to in naïve rats) were unchanged/inhibited by ISO only; similarly, several genes maximally inhibited in WTC dust rats were largely induced/unchanged in rats that received ISO only. These outcomes reflect likely contrasting effects of ISO and the WTC dust on lung gene expression. Overall, the data show that lungs of rats exposed to WTC dust (under ISO) – after accounting for any impact from ISO alone – displayed increased expression of genes related to lung inflammation, oxidative stress, and cell cycle control, while several involved in anti-oxidant function were inhibited. These changes suggested acute inflammogenic effects and oxidative stress in the lungs of WTC dust-exposed rats. This study, thus, concludes that a single very high exposure to WTC dusts could

  19. Incorporating High-Throughput Exposure Predictions with ...

    EPA Pesticide Factsheets

    We previously integrated dosimetry and exposure with high-throughput screening (HTS) to enhance the utility of ToxCast™ HTS data by translating in vitro bioactivity concentrations to oral equivalent doses (OEDs) required to achieve these levels internally. These OEDs were compared against regulatory exposure estimates, providing an activity-to-exposure ratio (AER) useful for a risk-based ranking strategy. As ToxCast™ efforts expand (i.e., Phase II) beyond food-use pesticides towards a wider chemical domain that lacks exposure and toxicity information, prediction tools become increasingly important. In this study, in vitro hepatic clearance and plasma protein binding were measured to estimate OEDs for a subset of Phase II chemicals. OEDs were compared against high-throughput (HT) exposure predictions generated using probabilistic modeling and Bayesian approaches generated by the U.S. EPA ExpoCast™ program. This approach incorporated chemical-specific use and national production volume data with biomonitoring data to inform the exposure predictions. This HT exposure modeling approach provided predictions for all Phase II chemicals assessed in this study whereas estimates from regulatory sources were available for only 7% of chemicals. Of the 163 chemicals assessed in this study, three or 13 chemicals possessed AERs <1 or <100, respectively. Diverse bioactivities y across a range of assays and concentrations was also noted across the wider chemical space su

  20. Secondhand smoke exposure and serum cytokine levels in healthy children.

    PubMed

    Wilson, Karen M; Wesgate, Sarah C; Pier, Jennifer; Weis, Emily; Love, Tanzy; Evans, Katie; Chhibber, Ashwani

    2012-10-01

    Exposure to secondhand smoke (SHS) is associated with morbidity in children. Alterations in immune responses may explain this relationship, but have not been well-studied in children. Our objective was to determine the association between SHS exposure and serum cytokine levels in healthy children. We recruited 1-6 year old patients undergoing routine procedures. A parent interview assessed medical history and SHS exposure. Children with asthma were excluded. Blood was collected under anesthesia. We used Luminex Multiplex Assays to test for a panel of cytokines; cotinine was determined using an enzyme-linked immunosorbent assay. Children were categorized as no, intermediate, or high exposure. A mixed-effects model was fit to determine differences in cytokines by exposure level. Of the 40 children recruited, 65% (N=26) had SHS exposure; 16 intermediate, and 10 high. There were no differences by demographics. In bivariate analyses, children exposed to SHS had lower concentrations of IL-1β, IL-4, IL-5, and IFN-γ than those with no exposure. In the mixed-effects model, children with any SHS exposure had significantly lower concentrations of IL-1β (0.554 pg/mL vs. 0.249 pg/mL) and IFN-γ (4.193 pg/mL vs. 0.816 pg/mL), and children with high exposure had significantly lower mean concentrations of IL-4 (8.141 pg/mL vs. 0.135 pg/mL) than children with no exposure. This study suggests that SHS exposure decreases expression of some pro-inflammatory cytokines in SHS exposed children, including IFN-γ. Further research to describe the acute and chronic effects of SHS on the immune systems of children is needed. Copyright © 2012 Elsevier Ltd. All rights reserved.

  1. Infection in Health Personnel with High and Low Levels of Exposure in a Hospital Setting during the H1N1 2009 Influenza A Pandemic.

    PubMed

    Sandoval, Carmen; Barrera, Aldo; Ferrés, Marcela; Cerda, Jaime; Retamal, Javiera; García-Sastre, Adolfo; Medina, Rafael A; Hirsch, Tamara

    2016-01-01

    A novel H1N1 influenza A virus caused the first pandemic of the 21st century in 2009. Hospitals had an increased demand of health consultations, that made it difficult to estimate the incidence of infection in hospital personnel due to asymptomatic presentations and the under notification of cases. To estimate and compare the rate of exposure of high versus low risk health personnel to 2009 pandemic H1N1 (H1N1pdm2009) influenza A virus in a University Hospital in Chile, we performed a comparative and prospective study. Serum samples were obtained from 117 individuals that worked in the emergency room (ER) and the operating room (OR) during the peak of the pandemic. Antibody titers were determined by the hemagglutination inhibition (HI) assay. Of the samples analyzed, 65% were workers at the ER and 35% at the OR. Of the total number of the subjects tested, 29.1% were seropositive. One out of 3 (36.8%) workers at the ER had positive HI titers, meanwhile only 1 out of 7 (14.6%) workers from the OR was seropositive to the virus. The possibility of being infected in the ER as compared to the OR was 3.4 times greater (OR 3.4; CI 95%, 1.27-9.1), and the individuals of the ER had almost twice as much antibody titers against H1N1pdm2009 than the personnel in the OR, suggesting the potential of more than one exposure to the virus. Of the 34 seropositive subjects, 12 (35.3%) did not develop influenza like illness, including 2 non-clinical personnel involved in direct contact with patients at the ER. Considering the estimated population attack rate in Chile of 13%, both groups presented a higher exposure and seropositive rate than the general population, with ER personnel showing greater risk of infection and a significantly higher level of antibodies. This data provide a strong rationale to design improved control measures aimed at all the hospital personnel, including those coming into contact with the patients prior to triage, to prevent the propagation and transmission of

  2. Infection in Health Personnel with High and Low Levels of Exposure in a Hospital Setting during the H1N1 2009 Influenza A Pandemic

    PubMed Central

    Sandoval, Carmen; Barrera, Aldo; Ferrés, Marcela; Cerda, Jaime; Retamal, Javiera; García-Sastre, Adolfo; Medina, Rafael A.; Hirsch, Tamara

    2016-01-01

    A novel H1N1 influenza A virus caused the first pandemic of the 21st century in 2009. Hospitals had an increased demand of health consultations, that made it difficult to estimate the incidence of infection in hospital personnel due to asymptomatic presentations and the under notification of cases. To estimate and compare the rate of exposure of high versus low risk health personnel to 2009 pandemic H1N1 (H1N1pdm2009) influenza A virus in a University Hospital in Chile, we performed a comparative and prospective study. Serum samples were obtained from 117 individuals that worked in the emergency room (ER) and the operating room (OR) during the peak of the pandemic. Antibody titers were determined by the hemagglutination inhibition (HI) assay. Of the samples analyzed, 65% were workers at the ER and 35% at the OR. Of the total number of the subjects tested, 29.1% were seropositive. One out of 3 (36.8%) workers at the ER had positive HI titers, meanwhile only 1 out of 7 (14.6%) workers from the OR was seropositive to the virus. The possibility of being infected in the ER as compared to the OR was 3.4 times greater (OR 3.4; CI 95%, 1.27–9.1), and the individuals of the ER had almost twice as much antibody titers against H1N1pdm2009 than the personnel in the OR, suggesting the potential of more than one exposure to the virus. Of the 34 seropositive subjects, 12 (35.3%) did not develop influenza like illness, including 2 non-clinical personnel involved in direct contact with patients at the ER. Considering the estimated population attack rate in Chile of 13%, both groups presented a higher exposure and seropositive rate than the general population, with ER personnel showing greater risk of infection and a significantly higher level of antibodies. This data provide a strong rationale to design improved control measures aimed at all the hospital personnel, including those coming into contact with the patients prior to triage, to prevent the propagation and transmission

  3. Exposure assessment of potash miners at elevated CO2 levels.

    PubMed

    Monsé, Christian; Broding, Horst Christoph; Sucker, Kirsten; Berresheim, Hans; Jettkant, Birger; Hoffmeyer, Frank; Merget, Rolf; Brüning, Thomas; Bünger, Jürgen

    2014-05-01

    In a potash mine in the center of Germany, stationary measurements 40 cm above ground level have revealed occasional increases in the carbon dioxide (CO2) levels that exceed the 0.5 vol.% German occupational exposure limit (OEL). This study, therefore, aimed to examine the individual exposures of potash miners to CO2 at their underground workplaces. 119 miners were equipped with personal CO2 detectors to log the individual CO2 exposures during underground work. We decided to use electrochemical monitors due to their compactness and minimal mass. Furthermore, generated CO2 measurements with precipitated overshooting and false positive CO2 values were studied using diverse CO2 test gases and different fumigation times. The personal detectors showed short-term CO2 peak exposures at very high concentrations in a limited number of workers. Twenty-two threshold limit value violations were observed according to the present OEL, and the personal CO2 monitoring allowed categorization into three exposure groups, low (n = 83), moderate (n = 26) and high burdens (n = 10) of CO2. The electrochemical sensors used have numerous properties that can potentially influence the assessment of exposures. The current findings suggest that assessing similar exposure scenarios, with respect to elevated and strongly fluctuating CO2 concentrations, the behavior of electrochemical sensors should be taken into consideration.

  4. Exposure level of ergonomic risk factors in hotel industries

    NASA Astrophysics Data System (ADS)

    Nasrull Abdol Rahman, Mohd; Syahir Muhamad Jaffar, Mohd; Fahrul Hassan, Mohd; Zamani Ngali, Mohd; Pauline, Ong

    2017-08-01

    Ergonomic Risk Factors (ERFs) which contribute to Musculoskeletal Disorders (MSDs) among room attendants were considered as a problem or trouble since these ERFs would affect their work performance for hotel industries. The purpose of this study was to examine the exposure level of ERFs among room attendants in hotel industries. 65 of respondents were obtained from selected hotels in Peninsular Malaysia. Data were collected by direct observation via Workplace Ergonomic Risk Assessment (WERA) and Quick Exposure Checklist (QEC). There were 36 males and 29 females room attendants involved throughout the research. Most of room attendants experienced high exposure level for back, leg, forceful and vibration based on the exposure level evaluation through WERA while QEC results showed that all room attendants were found to have moderate exposure level for risk factors including back for movement use, shoulders/arms, wrists/hands and neck. All the results obtained showed that the related ERFs for MSDs were associated and essential ergonomic interventions are needed in order to eliminate risk of exposures to MSDs among room attendants in hotel industries.

  5. Health effects of low-level exposure to polychlorinated biphenyls.

    PubMed

    Stark, A D; Costas, K; Chang, H G; Vallet, H L

    1986-10-01

    A polychlorinated biphenyl (PCB) spill resulting from a transformer explosion in Syracuse, New York, with no subsequent fire, provided an opportunity for the examination of the effects of low-level PCB exposure without the confounding presence of furans and dioxins. The incident provided 52 individuals exposed to PCB among building personnel, police, firemen, and public utility employees. Sixty-eight nonexposed were matched to the exposed group by sex, age, employer, and job description. Data were collected on the exposed relative to their activities at the spill site, their location, possible routes of exposure, duration of exposure, and subsequent health effects. Exposed and nonexposed were interviewed for past medical history and relevant symptoms. Blood chemistries were studied inclusive of SGOT, SGPT, total protein, CBC, cholesterol, and triglyceride levels, as well as a fasting blood PCB level measurement. Six weeks after the spill, exposed and nonexposed were reinterviewed and had their blood work repeated except for the CBC and PCB levels. Exposed and nonexposed laboratory results were unremarkable. Some transient skin irritation believed to be associated with PCBs was noted. There were significant PCBs in blood level trends for occupation, age, duration of exposure, and level of alcohol consumption. Triglyceride level was highly correlated with PCB level. This relationship held when age and alcohol consumption were controlled for.

  6. Health effects of low-level exposure to polychlorinated biphenyls

    SciTech Connect

    Stark, A.D.; Costas, K.; Chang, H.G.; Vallet, H.L.

    1986-10-01

    A polychlorinated biphenyl (PCB) spill resulting from a transformer explosion in Syracuse, New York, with no subsequent fire, provided an opportunity for the examination of the effects of low-level PCB exposure without the confounding presence of furans and dioxins. The incident provided 52 individuals exposed to PCB among building personnel, police, firemen, and public utility employees. Sixty-eight nonexposed were matched to the exposed group by sex, age, employer, and job description. Data were collected on the exposed relative to their activities at the spill site, their location, possible routes of exposure duration of exposure, and subsequent health effects. Exposed and nonexposed were interviewed for past medical history and relevant symptoms. Blood chemistries were studied inclusive of SGOT, SGPT, total protein, CBC, cholesterol, and triglyceride levels, as well as a fasting blood PCB level measurement. Six weeks after the spill, exposed and nonexposed were re-interviewed and had their blood work repeated except for the CBC and PCB levels. Exposed and nonexposed laboratory results were unremarkable. Some transient skin irritation believed to be associated with PCBs was noted. There were significant PCBs in blood level trends for occupation, age, duration of exposure, and level of alcohol consumption. Triglyceride level was highly correlated with PCB level. This relationship held when age and alcohol consumption were controlled for.

  7. Development of acute exposure guideline levels for airborne exposures to hazardous substances.

    PubMed

    Krewski, Daniel; Bakshi, Kulbir; Garrett, Roger; Falke, Ernest; Rusch, George; Gaylor, David

    2004-04-01

    Hazardous substances can be released into the atmosphere due to industrial and transportation accidents, fires, tornadoes, earthquakes, and terrorists, thereby exposing workers and the nearby public to potential adverse health effects. Various enforceable guidelines have been set by regulatory agencies for worker and ambient air quality. However, these exposure levels generally are not applicable to rare lifetime acute exposures, which possibly could occur at high concentrations. Acute exposure guideline levels (AEGLs) provide estimates of concentrations for airborne exposures for an array of short durations that possibly could cause mild (AEGL-1), severe, irreversible, potentially disabling adverse health effects (AEGL-2), or life threatening effects (AEGL-3). These levels can be useful for emergency responders and planners in reducing or eliminating potential risks to the public. Procedures and methodologies for deriving AEGLs are reviewed in this paper that have been developed in the United States, with direct input from international representatives of OECD member-countries, by the National Advisory Committee for Acute Exposure Guidelines for Hazardous Substances and reviewed by the National Research Council. Techniques are discussed for the extrapolation of effects across different exposure durations. AEGLs provide a viable approach for assisting in the prevention, planning, and response to acute airborne exposures to toxic agents.

  8. Nickel exposure and plasma levels of biomarkers for assessing oxidative stress in nickel electroplating workers.

    PubMed

    Tsao, Yu-Chung; Gu, Po-Wen; Liu, Su-Hsun; Tzeng, I-Shiang; Chen, Jau-Yuan; Luo, Jiin-Chyuan John

    2017-07-01

    The mechanism of nickel-induced pathogenesis remains elusive. To examine effects of nickel exposure on plasma oxidative and anti-oxidative biomarkers. Biomarker data were collected from 154 workers with various levels of nickel exposure and from 73 controls. Correlations between nickel exposure and oxidative and anti-oxidative biomarkers were determined using linear regression models. Workers with a exposure to high nickel levels had significantly lower levels of anti-oxidants (glutathione and catalase) than those with a lower exposure to nickel; however, only glutathione showed an independent association after multivariable adjustment. Exposure to high levels of nickel may reduce serum anti-oxidative capacity.

  9. High level nuclear waste

    SciTech Connect

    Crandall, J L

    1980-01-01

    The DOE Division of Waste Products through a lead office at Savannah River is developing a program to immobilize all US high-level nuclear waste for terminal disposal. DOE high-level wastes include those at the Hanford Plant, the Idaho Chemical Processing Plant, and the Savannah River Plant. Commercial high-level wastes, for which DOE is also developing immobilization technology, include those at the Nuclear Fuel Services Plant and any future commercial fuels reprocessing plants. The first immobilization plant is to be the Defense Waste Processing Facility at Savannah River, scheduled for 1983 project submission to Congress and 1989 operation. Waste forms are still being selected for this plant. Borosilicate glass is currently the reference form, but alternate candidates include concretes, calcines, other glasses, ceramics, and matrix forms.

  10. Canopy-level stomatal narrowing in adult Fagus sylvatica under O3 stress - means of preventing enhanced O3 uptake under high O3 exposure?

    PubMed

    Matyssek, R; Baumgarten, M; Hummel, U; Häberle, K-H; Kitao, M; Wieser, G

    2015-01-01

    Spatio-temporally consistent O(3) doses are demonstrated in adult Fagus sylvatica from the Kranzberg Forest free-air fumigation experiment, covering cross-canopy and whole-seasonal scopes through sap flow measurement. Given O(3)-driven closure of stomata, we hypothesized enhanced whole-tree level O(3) influx to be prevented under enhanced O(3) exposure. Although foliage transpiration rate was lowered under twice-ambient O(3) around noon by 30% along with canopy conductance, the hypothesis was falsified, as O(3) influx was raised by 25%. Nevertheless, the twice-ambient/ambient ratio of O(3) uptake was smaller by about 20% than that of O(3) exposure, suggesting stomatal limitation of uptake. The O(3) response was traceable from leaves across branches to the canopy, where peak transpiration rates resembled those of shade rather than sun branches. Rainy/overcast-day and nightly O(3) uptake is quantified and discussed. Whole-seasonal canopy-level validation of modelled with sap flow-derived O(3) flux becomes available in assessing O(3) risk for forest trees.

  11. 30 CFR 57.5042 - Revised exposure levels.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Revised exposure levels. 57.5042 Section 57..., Radiation, Physical Agents, and Diesel Particulate Matter Radiation-Underground Only § 57.5042 Revised exposure levels. If levels of permissible exposures to concentrations of radon daughters different...

  12. 30 CFR 57.5042 - Revised exposure levels.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Revised exposure levels. 57.5042 Section 57..., Radiation, Physical Agents, and Diesel Particulate Matter Radiation-Underground Only § 57.5042 Revised exposure levels. If levels of permissible exposures to concentrations of radon daughters different...

  13. 30 CFR 57.5042 - Revised exposure levels.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Revised exposure levels. 57.5042 Section 57..., Radiation, Physical Agents, and Diesel Particulate Matter Radiation-Underground Only § 57.5042 Revised exposure levels. If levels of permissible exposures to concentrations of radon daughters different...

  14. Assessing the level of chromosome aberrations in peripheral blood lymphocytes in long-term resident children under conditions of high exposure to radon and its decay products.

    PubMed

    Druzhinin, Vladimir G; Sinitsky, Maxim Yu; Larionov, Aleksey V; Volobaev, Valentin P; Minina, Varvara I; Golovina, Tatiana A

    2015-09-01

    In this study, the frequency and spectrum of chromosomal aberrations were analysed in samples of peripheral blood from 372 (mean age = 12.24 ± 2.60 years old) long-term resident children in a boarding school (Tashtagol city, Kemerovo Region, Russian Federation) under conditions of high exposure to radon and its decay products. As a control group, we used blood samples from people living in Zarubino village (Kemerovo Region, Russian Federation). We discovered that the average frequencies of single and double fragments, chromosomal exchanges, total number of aberrations, chromatid type, chromosome type and all types of aberrations were significantly increased in the exposed group. This is evidence of considerable genotoxicity to children living under conditions of high exposure to radon compared to children living under ecological conditions without increased radon radiation. © The Author 2015. Published by Oxford University Press on behalf of the UK Environmental Mutagen Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  15. Endogenous cortisol levels influence exposure therapy in spider phobia.

    PubMed

    Lass-Hennemann, Johanna; Michael, Tanja

    2014-09-01

    Previous research in patients with phobia showed that the administration of glucocorticoids reduces fear in phobic situations and enhances exposure therapy. Glucocorticoids underlie a daily cycle with a peak in the morning and low levels during the evening and night. The aim of the present study was to investigate whether exposure is more effective when conducted in the morning when endogenous cortisol levels are high. Sixty patients meeting DSM IV criteria for specific phobia (animal type) were randomly assigned to one-session exposure treatment either at 08.00 a.m. (high cortisol group) or at 06.00 p.m. (low cortisol group). Participants returned for a posttreatment assessment one week after therapy and a follow-up assessment three months after therapy. Both groups showed good outcome, but patients treated in the morning exhibited significantly less fear of spiders in the behavioral approach test (BAT) and a trend for lower scores on the Fear of Spiders Questionnaire (FSQ) than patients treated in the evening. This effect was present at posttreatment and follow-up. Our findings indicate that exposure therapy is more effective in the morning than in the evening. We suggest that this may be due to higher endogenous cortisol levels in the morning group that enhance extinction memory.

  16. 30 CFR 62.130 - Permissible exposure level.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Permissible exposure level. 62.130 Section 62.130 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR UNIFORM MINE HEALTH REGULATIONS OCCUPATIONAL NOISE EXPOSURE § 62.130 Permissible exposure level. (a) The mine operator must assure...

  17. Metabonomics of Pig Blood Plasma Following Whole Body Exposure to Low Levels of Gb Vapor

    DTIC Science & Technology

    2005-10-01

    METABONOMICS OF PIG BLOOD PLASMA FOLLOWING WHOLE BODY EXPOSURE TO LOW LEVELS OF GB VAPOR Vicky L. H. Bevilacqua▲, Terrence G...DATES COVERED - 4. TITLE AND SUBTITLE Metabonomics Of Pig Blood Plasma Following Whole Body Exposure To Low Levels Of Gb Vapor 5a. CONTRACT...analysis of minipig blood plasma by high field NMR after low-level exposure to GB by whole body inhalation. EXPERIMENTAL METHODS 1. SARIN

  18. Formaldehyde exposure in a gross anatomy laboratory--personal exposure level is higher than indoor concentration.

    PubMed

    Ohmichi, Kimihide; Komiyama, Masatoshi; Matsuno, Yoshiharu; Takanashi, Yoshimitsu; Miyamoto, Hiroshi; Kadota, Tomoko; Maekawa, Mamiko; Toyama, Yoshiro; Tatsugi, Yukitoshi; Kohno, Toshihiko; Ohmichi, Masayoshi; Mori, Chisato

    2006-03-01

    Cadavers for gross anatomy laboratories are usually prepared by using embalming fluid which contains formaldehyde (FA) as a principal component. During the process of dissection, FA vapors are emitted from the cadavers, resulting in the exposure of medical students and their instructors to elevated levels of FA in the laboratory. The American Conference of Governmental Industrial Hygienists (ACGIH) has set a ceiling limit for FA at 0.3 ppm. In Japan, the Ministry of Health, Labour and Welfare has set an air quality guideline defining two limit values for environmental exposure to FA: 0.08 ppm as an average for general workplaces and 0.25 ppm for specific workplaces such as an FA factory. Although there are many reports on indoor FA concentrations in gross anatomy laboratories, only a few reports have described personal FA exposure levels. The purpose of the present study was to clarify personal exposure levels as well as indoor FA concentrations in our laboratory in order to investigate the relationship between them. The gross anatomy laboratory was evaluated in the 4th, 10th and 18th sessions of 20 laboratory sessions in total over a period of 10 weeks. Air samples were collected using a diffusive sampling device for organic carbonyl compounds. Area samples were taken in the center and four corners of the laboratory during the entire time of each session (4-6 hours). Personal samples were collected from instructors and students using a sampling device pinned on each person's lapel, and they were 1.1 to 6 hours in duration. Analysis was carried out using high performance liquid chromatography. Room averages of FA concentrations were 0.45, 0.38 and 0.68 ppm for the 4th, 10th and 18th sessions, respectively, ranging from 0.23 to 1.03 ppm. These levels were comparable to or relatively lower than the levels reported previously, but were still higher than the guideline limit for specific workplaces in Japan and the ACGIH ceiling limit. The indoor FA concentrations

  19. Ozone-induced foliar damage and release of stress volatiles is highly dependent on stomatal openness and priming by low-level ozone exposure in Phaseolus vulgaris.

    PubMed

    Li, Shuai; Harley, Peter C; Niinemets, Ülo

    2017-09-01

    Acute ozone exposure triggers major emissions of volatile organic compounds (VOCs), but quantitatively, it is unclear how different ozone doses alter the start and the total amount of these emissions, and the induction rate of different stress volatiles. It is also unclear whether priming (i.e. pre-exposure to lower O3 concentrations) can modify the magnitude and kinetics of volatile emissions. We investigated photosynthetic characteristics and VOC emissions in Phaseolus vulgaris following acute ozone exposure (600 nmol mol(-1) for 30 min) under illumination and in darkness and after priming with 200 nmol mol(-1) O3 for 30 min. Methanol and lipoxygenase (LOX) pathway product emissions were induced rapidly, followed by moderate emissions of methyl salicylate (MeSA). Stomatal conductance prior to acute exposure was lower in darkness and after low O3 priming than in light and without priming. After low O3 priming, no MeSA and lower LOX emissions were detected under acute exposure. Overall, maximum emission rates and the total amount of emitted LOX products and methanol were quantitatively correlated with total stomatal ozone uptake. These results indicate that different stress volatiles scale differently with ozone dose and highlight the key role of stomatal conductance in controlling ozone uptake, leaf injury and volatile release. © 2017 John Wiley & Sons Ltd.

  20. Prediction of Exposure Level of Energetic Solar Particle Events

    NASA Astrophysics Data System (ADS)

    Kim, M. H. Y.; Blattnig, S.

    2016-12-01

    The potential for exposure to large solar particle events (SPEs) with fluxes that extend to high energies is a major concern during interplanetary transfer and extravehicular activities (EVAs) on the lunar and Martian surfaces. Prediction of sporadic occurrence of SPEs is not accurate for near or long-term scales, while the expected frequency of such events is strongly influenced by solar cycle activity. In the development of NASA's operational strategies real-time estimation of exposure to SPEs has been considered so that adequate responses can be applied in a timely manner to reduce exposures to well below the exposure limits. Previously, the organ doses of large historical SPEs had been calculated by using the complete energy spectra of each event and then developing a prediction model for blood-forming organ (BFO) dose based solely on an assumed value of integrated fluence above 30 MeV (Φ30) for an otherwise unspecified future SPE. While BFO dose is determined primarily by solar protons with high energies, it was reasoned that more accurate BFO dose prediction models could be developed using integrated fluence above 60 MeV (Φ60) and above 100 MeV (Φ100) as predictors instead of Φ30. In the current study, re-analysis of major SPEs (in which the proton spectra of the ground level enhancement [GLE] events since 1956 are correctly described by Band functions) has been used in evaluation of exposure levels. More accurate prediction models for BFO dose and NASA effective dose are then developed using integrated fluence above 200 MeV (Φ200), which by far have the most weight in the calculation of doses for deep-seated organs from exposure to extreme SPEs (GLEs or sub-GLEs). The unconditional probability of a BFO dose exceeding a pre-specified BFO dose limit is simultaneously calculated by taking into account the distribution of the predictor (Φ30, Φ60, Φ100, or Φ200) as estimated from historical SPEs. These results can be applied to the development of

  1. Is Exposure to Low Radiation Levels Good For You?

    NASA Astrophysics Data System (ADS)

    Dimitroyannis, Dimitri

    1996-05-01

    Little is known about the biological effects of very low levels of ionizing radiation. We propose an experiment to compare cell response to such low radiation levels, using fast replicating yeast cells. Saccharomyces Cerevisae (SC), a type of yeast, is an eukariotic unicellular microorganism with a mean cell generation time of 90 min. Its genetic organization is similar to that of superior organisms, but at the same time is very easy to handle, with special reference to its genetic analysis. Certain CS strains are widely employed for mutagenesis studies. We propose to expose simultaneously three indentical CS cultures for a period of up to a few weeks (100s of cell generations): to natural backgroung (NB) ionizing radiation (at a ground level lab), to sub-NB level (underground) and to supra-NB level (at a high altitude). At the end of the exposure we will chemically challenge the cultured cells with methyl-methane-sulphonate (MMS), a standard chemical mutagen. Mitotic recombination frequency in the MMS exposed cultures is an index of early DNA damage induction at high survival levels (ie at very low radiation levels). This experiment can be handsomely and inexpensively accomodated in one of the existing underground laboratories.

  2. The High Price of Noise Exposure

    MedlinePlus

    ... Current Issue Past Issues Hearing Disorders The High Price of Noise Exposure Past Issues / Fall 2008 Table ... These tiny structures convert sound waves into electrical energy. Our auditory nerve sends this energy to the ...

  3. The influence of defect levels on the dose rate dependence of synthetic diamond detectors of various types on exposures to high-energy radiotherapy beams

    NASA Astrophysics Data System (ADS)

    Ade, N.; Nam, T. L.

    2015-03-01

    The linear response of a radiation dosimeter with absorbed dose rate is a principal requirement in radiotherapy. Fowler's model for electrical conductivity, σ of a solid-state detector and absorbed dose rate, Dr is of the form σ ∝ DrΔ where Δ is the linearity index that can take on a range of values around unity. Utilising synthetic diamond detectors of various types as sensors, this study investigates the influence of defect levels on the Δ values of the sensors and the dependence of Δ on bias voltage, beam energy and type in the dosimetry of high-energy photon and electron therapy beams. One main objective of the study was to establish whether for a given diamond detector, Δ could be determined only once for any given beam energy and then used for other beam energies of clinical interest. In order to attain the ICRU overall ±5% uncertainty of absorbed dose delivery in radiotherapy, ±2% accuracy was considered. The study was conducted on one HPHT and eight CVD synthesised diamonds of optical grade (OG) and detector grade (DG) qualities using 6 and 15 MV photon, and 7 and 12 MeV electron energies. Values of Δ ranging from 0.79-1.03 to 0.85-0.96 were obtained for the electron and photon beams, respectively for all the diamond sensors at 1 kV/cm. The Δ values were found to change with various defect levels present within the crystals as characterised by Raman spectroscopy, ESR, FTIR spectroscopy and TL emission, and it was observed that the Δ values of crystals with high defect levels varied strongly with bias voltage. Whereas the Δ values of the HPHT diamond were found not vary with the electron and photon energies, only those of three CVD samples of a given class showed a variation within 2% between the two energies of each beam type. However, for all the crystals tested Δ showed a maximum variation of 3.4% between the photon energies unlike the electron energies where a very strong variation (>5%) was observed for three OG CVD crystals. The results

  4. Thalamic GABA levels and occupational manganese neurotoxicity: Association with exposure levels and brain MRI.

    PubMed

    Ma, Ruoyun E; Ward, Eric J; Yeh, Chien-Lin; Snyder, Sandy; Long, Zaiyang; Gokalp Yavuz, Fulya; Zauber, S Elizabeth; Dydak, Ulrike

    2017-09-02

    Excessive occupational exposure to Manganese (Mn) has been associated with clinical symptoms resembling idiopathic Parkinson's disease (IPD), impairing cognitive and motor functions. Several studies point towards an involvement of the brain neurotransmitter system in Mn intoxication, which is hypothesized to be disturbed prior to onset of symptoms. Edited Magnetic Resonance Spectroscopy (MRS) offers the unique possibility to measure γ-amminobutyric acid (GABA) and other neurometabolites in vivo non-invasively in workers exposed to Mn. In addition, the property of Mn as Magnetic Resonance Imaging (MRI) contrast agent may be used to study Mn deposition in the human brain. In this study, using MRI, MRS, personal air sampling at the working place, work history questionnaires, and neurological assessment (UPDRS-III), the effects of chronic Mn exposure on the thalamic GABAergic system was studied in a group of welders (N=39) with exposure to Mn fumes in a typical occupational setting. Two subgroups of welders with different exposure levels (Low: N=26; mean air Mn=0.13±0.1mg/m(3); High: N=13; mean air Mn=0.23±0.18mg/m(3)), as well as unexposed control workers (N=22, mean air Mn=0.002±0.001mg/m(3)) were recruited. The group of welders with higher exposure showed a significant increase of thalamic GABA levels by 45% (p<0.01, F(1,33)=9.55), as well as significantly worse performance in general motor function (p<0.01, F(1,33)=11.35). However, welders with lower exposure did not differ from the controls in GABA levels or motor performance. Further, in welders the thalamic GABA levels were best predicted by past-12-months exposure levels and were influenced by the Mn deposition in the substantia nigra and globus pallidus. Importantly, both thalamic GABA levels and motor function displayed a non-linear pattern of response to Mn exposure, suggesting a threshold effect. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. [Lead exposure in the ceramic tile industry: time trends and current exposure levels].

    PubMed

    Candela, S; Ferri, F; Olmi, M

    1998-01-01

    There is a high density of industries for the production of ceramic tiles in the District of Scandiano (province of Reggio Emilia, Emilia Romagna region). In this area, since the beginning of 1970s, the time trend of Pb exposure in ceramic tile plants has been evaluated by means of biological monitoring (BM) data collected at the Service of Prevention and Safety in the Work Environment and its associated Toxicology Laboratory. From these data, a clear decreasing time trend of exposure levels is documented, the reduction being more evident during the seventies and in 1985-88. During the seventies BM was introduced systematically in all ceramic tile plants with the determination of delta-aminolevulinic acid in urine (ALA-U). As a consequence of the BM programme, hygienic measures for the abatement of pollution inside the plants were implemented, and a reduction, from 20.6% to 2%, of ALA-U values exceeding 10 mg/l, was observed. In 1985, the determination of lead in blood (PbB) replaced that of ALA-U in the BM programmes and highlighted the persistence of high level of exposure to Pb, which could not be outlined by means of ALA-U because of its lower sensitivity. PbB levels were 36.1 micrograms/100 ml and 25.7 micrograms/100 ml in male and female workers, respectively. These results required the implementation, within the plants, of additional hygienic measures and a significant reduction of PbB was obtained in the following three years. In 1988 PbB levels were 26.0 +/- 10.7 and 21.6 +/- 10.3 micrograms/100 ml in male and female workers, respectively. In 1993-95 Pb levels were obtained from 1328 male and 771 female workers of 56 plants, accounting for about 40% of the total number of workers in the ceramic industry, in the zones of Sassuolo and Scandiano. Exposure levels are not different from those observed in the preceding years, with PbB levels of 25.3 +/- 11.1 and 19.1 +/- 9.2 micrograms/100 ml in male and female workers, respectively.

  6. Human exposure assessment: a graduate level course

    SciTech Connect

    Lioy, P.J. )

    1991-07-01

    The course has been offered three times. The content and the approach to each lecture has evolved after each time it was given. This is not unexpected since the field has been undergoing major transformations, and new approaches to measurement and modeling are being applied to current problems. The most recent student evaluation, 1990, indicates a difficulty rating of just right' (70%) to difficult' (30%). Most felt the course stimulated their interest in the topic (72%) and the examinations were learning experiences as well as a grading exercise. The major need for the discipline is an adequate text book. The GRAPE program has excellent potential as an educational tool, but it needs to make more interactions and allow introduction of activities and data. The major strengths of the course are the problems provided to the students for homework. These give the student quantitative perspective on the concepts, range in values, variables, and uncertainties necessary to complete an assessment. In addition, the development of the mathematical and conceptional continuum for placing exposure assessment in the context of toxicology, environmental science, epidemiology, and clinical intervention provides a basic framework for the discipline.

  7. Human exposure assessment: a graduate level course.

    PubMed

    Lioy, P J

    1991-07-01

    The course has been offered three times. The content and the approach to each lecture has evolved after each time it was given. This is not unexpected since the field has been undergoing major transformations, and new approaches to measurement and modeling are being applied to current problems. The most recent student evaluation, 1990, indicates a difficulty rating of "just right" (70%) to "difficult" (30%). Most felt the course stimulated their interest in the topic (72%) and the examinations were learning experiences as well as a grading exercise. The major need for the discipline is an adequate text book. The GRAPE program has excellent potential as an educational took, but it needs to make more interactions and allow introduction of activities and data. The major strengths of the course are the problems provided to the students for homework. These give the student quantitative perspective on the concepts, range in values, variables, and uncertainties necessary to complete an assessment. In addition, the development of the mathematical and conceptional continuum for placing exposure assessment in the context of toxicology, environmental science, epidemiology, and clinical intervention provides a basic framework for the discipline.

  8. 30 CFR 62.130 - Permissible exposure level.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Permissible exposure level. 62.130 Section 62.130 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR UNIFORM MINE HEALTH... must use all feasible engineering and administrative controls to reduce the miner's noise exposure to...

  9. 30 CFR 62.130 - Permissible exposure level.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Permissible exposure level. 62.130 Section 62.130 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR UNIFORM MINE HEALTH... must use all feasible engineering and administrative controls to reduce the miner's noise exposure to...

  10. 30 CFR 62.130 - Permissible exposure level.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Permissible exposure level. 62.130 Section 62.130 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR UNIFORM MINE HEALTH... must use all feasible engineering and administrative controls to reduce the miner's noise exposure to...

  11. 30 CFR 62.130 - Permissible exposure level.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Permissible exposure level. 62.130 Section 62.130 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR UNIFORM MINE HEALTH... must use all feasible engineering and administrative controls to reduce the miner's noise exposure to...

  12. Occupational airways diseases from chronic low-level exposures to irritants.

    PubMed

    Balmes, John R

    2002-12-01

    Short-term, high-level exposures to dusts, gases, mists, fumes, and smoke that are irritating to the respiratory tract are capable of inducing asthma, the so-called reactive airways dysfunction syndrome. Such exposures, however, do not occur frequently; chronic or recurrent exposures to lower levels of irritants are much more common. This article reviews the evidence that supports the concept that low-level exposures to respiratory tract irritants can contribute to the development of chronic obstructive pulmonary disease and asthma.

  13. Individual and city-level determinants of secondhand smoke exposure in China.

    PubMed

    Yang, Tingzhong; Jiang, Shuhang; Barnett, Ross; Peng, Sihui; Yu, Lingwei

    2015-12-29

    Second hand smoke (SHS) exposure is a severe public health problem, especially in low and middle countries, but no studies have examined both individual and city-level variables influencing exposure. A cross-sectional multistage sampling design was used to survey subjects from 21 cities in China. Using a standardized questionnaire individual level information was collected. City-level variables were retrieved from the National Bureau of Statistics database. Multilevel logistic regression analysis was used to assess SHS exposure variation at both the individual and city level. SHS exposure prevalence among non-smokers was 28.1% (95% CI 27.1-29.0). At the individual level lower educational attainment and income and higher exposure to tobacco advertising were associated with higher SHS exposure. On the other hand richer cities, and those with more anti-smoking media news coverage, had less SHS exposure. The presence of city smokefree regulations was unrelated to exposure. Given its human and economic costs, reducing SHS exposure should receive greater priority than it does in China. The results point to the need for the enactment of national smokefree laws in order to combat unacceptably high levels of SHS exposure.

  14. High Dynamic Range Imaging Using Multiple Exposures

    NASA Astrophysics Data System (ADS)

    Hou, Xinglin; Luo, Haibo; Zhou, Peipei; Zhou, Wei

    2017-06-01

    It is challenging to capture a high-dynamic range (HDR) scene using a low-dynamic range (LDR) camera. This paper presents an approach for improving the dynamic range of cameras by using multiple exposure images of same scene taken under different exposure times. First, the camera response function (CRF) is recovered by solving a high-order polynomial in which only the ratios of the exposures are used. Then, the HDR radiance image is reconstructed by weighted summation of the each radiance maps. After that, a novel local tone mapping (TM) operator is proposed for the display of the HDR radiance image. By solving the high-order polynomial, the CRF can be recovered quickly and easily. Taken the local image feature and characteristic of histogram statics into consideration, the proposed TM operator could preserve the local details efficiently. Experimental result demonstrates the effectiveness of our method. By comparison, the method outperforms other methods in terms of imaging quality.

  15. Radon levels in Romanian caves: an occupational exposure survey.

    PubMed

    Cucoş Dinu, Alexandra; Călugăr, Monica I; Burghele, Bety D; Dumitru, Oana A; Cosma, Constantin; Onac, Bogdan P

    2016-10-01

    A comprehensive radon survey has been carried out in seven caves located in the western half of Romania's most significant karst regions. Touristic and non-touristic caves were investigated with the aim to provide a reliable distribution of their radon levels and evaluate the occupational exposure and associated effective doses. Radon gas concentrations were measured with long-term diffusion-type detectors during two consecutive seasons (warm and cold). All investigated caves exceed the European Union reference level of radon gas at workplaces (300 Bq/m(3)). The radon concentration in these caves ranges between 53 and 2866 Bq/m(3), reflecting particular cave topography, season-related cave ventilation, and complex tectonic and geological settings surrounding each location. Relatively homogeneous high radon levels occur in all investigated touristic caves and in Tăuşoare and Vântului along their main galleries. Except for Muierii, in all the other caves radon levels are higher during the warm season, compared to the cold one. This suggests that natural cave ventilation largely controls the underground accumulation of radon. The results reported here reveal that the occupational exposure in Urşilor, Vadu Crişului, Tăuşoare, Vântului, and Muierii caves needs to be carefully monitored. The effective doses to workers vary between an average of 0.25 and 4.39 mSv/year depending on the measuring season. The highest values were recorded in show caves, ranging from 1.15 to 6.15 mSv/year, well above the European recommended limit, thus posing a potential health hazard upon cave guides, cavers, and scientists.

  16. The effects of high level infrasound

    SciTech Connect

    Johnson, D.L.

    1980-02-01

    This paper will attempt to survey the current knowledge on the effects of relative high levels of infrasound on humans. While this conference is concerned mainly about hearing, some discussion of other physiological effects is appropriate. Such discussion also serves to highlight a basic question, 'Is hearing the main concern of infrasound and low frequency exposure, or is there a more sensitive mechanism'. It would be comforting to know that the focal point of this conference is indeed the most important concern. Therefore, besides hearing loss and auditory threshold of infrasonic and low frequency exposure, four other effects will be provided. These are performance, respiration, annoyance, and vibration.

  17. Long-Term Pancreatic Beta Cell Exposure to High Levels of Glucose but Not Palmitate Induces DNA Methylation within the Insulin Gene Promoter and Represses Transcriptional Activity

    PubMed Central

    Ishikawa, Kota; Tsunekawa, Shin; Ikeniwa, Makoto; Izumoto, Takako; Iida, Atsushi; Ogata, Hidetada; Uenishi, Eita; Seino, Yusuke; Ozaki, Nobuaki; Sugimura, Yoshihisa; Hamada, Yoji; Kuroda, Akio; Shinjo, Keiko; Kondo, Yutaka; Oiso, Yutaka

    2015-01-01

    Recent studies have implicated epigenetics in the pathophysiology of diabetes. Furthermore, DNA methylation, which irreversibly deactivates gene transcription, of the insulin promoter, particularly the cAMP response element, is increased in diabetes patients. However, the underlying mechanism remains unclear. We aimed to investigate insulin promoter DNA methylation in an over-nutrition state. INS-1 cells, the rat pancreatic beta cell line, were cultured under normal-culture-glucose (11.2 mmol/l) or experimental-high-glucose (22.4 mmol/l) conditions for 14 days, with or without 0.4 mmol/l palmitate. DNA methylation of the rat insulin 1 gene (Ins1) promoter was investigated using bisulfite sequencing and pyrosequencing analysis. Experimental-high-glucose conditions significantly suppressed insulin mRNA and increased DNA methylation at all five CpG sites within the Ins1 promoter, including the cAMP response element, in a time-dependent and glucose concentration-dependent manner. DNA methylation under experimental-high-glucose conditions was unique to the Ins1 promoter; however, palmitate did not affect DNA methylation. Artificial methylation of Ins1 promoter significantly suppressed promoter-driven luciferase activity, and a DNA methylation inhibitor significantly improved insulin mRNA suppression by experimental-high-glucose conditions. Experimental-high-glucose conditions significantly increased DNA methyltransferase activity and decreased ten-eleven-translocation methylcytosine dioxygenase activity. Oxidative stress and endoplasmic reticulum stress did not affect DNA methylation of the Ins1 promoter. High glucose but not palmitate increased ectopic triacylglycerol accumulation parallel to DNA methylation. Metformin upregulated insulin gene expression and suppressed DNA methylation and ectopic triacylglycerol accumulation. Finally, DNA methylation of the Ins1 promoter increased in isolated islets from Zucker diabetic fatty rats. This study helps to clarify the

  18. Behavioral effects of low level neonatal lead exposure.

    PubMed

    Hastings, L; Cooper, G P; Bornschein, R L; Michaelson, I A

    1977-07-01

    Rats exposed to lead via maternal milk were tested at various stages of development on a number of behavioral tasks. Beginning at paturition, the dams were given either tap water, 0.02%, or 0.10% lead acetate in the drinking water. Pups from all three groups were weaned to normal chow and tap water at 21 days of age. The mean lead concentration of the dam's blood and of neonatal (20 days of age) brain and blood were all below 50 microgram/100 ml. No significant differences were found between the high lead-exposed group and controls in general as measured by wheel running over a 21 day period beginning at 30 days of age. However, there was a significant difference in wheel running behavior during the first three hr of testing. Both lead-exposed groups were found to display significantly less aggressive behavior as measured by the shock-elicited aggression test. Low level lead exposure had no discernable effect on the acquisition and subsequent reversal of a successive brightness discrimination task. Lead exposure under these conditions appears to affect some aspects of emotional behavior, while having little effect on general activity or cognitive function.

  19. Relating indoor NO 2 levels to infant personal exposures

    NASA Astrophysics Data System (ADS)

    Harlos, David P.; Marbury, Marian; Samet, Jonathan; Spengler, John D.

    We report here the results of a field survey of personal nitrogen dioxide exposure (PNO 2) of infants and simultaneous indoor NO 2 levels from various points throughout the infants' homes. Personal nitrogen dioxide levels can be predicted by average room NO 2 concentrations when appropriately weighted by infant presence in the room. Bedroom NO 2 concentration alone presents an alternative predictor which is more suitable for use in large scale surveys. Because of the typical infant's peculiar time-location patterns, they receive most of their NO 2 exposures in bedrooms (65 %)and living rooms (32 %), while the kitchen (5 %) and outdoor environments (> 2%)contribute only a small fraction of daily exposure. Average NO 2 exposure during cooking periods can be predicted using passive samplers placed directly over stoves and hours of stove use time.

  20. Mapping of radio frequency electromagnetic field exposure levels in outdoor environment and comparing with reference levels for general public health.

    PubMed

    Cansiz, Mustafa; Abbasov, Teymuraz; Kurt, M Bahattin; Celik, A Recai

    2016-11-02

    In this study, radio frequency electromagnetic field exposure levels were measured on the main streets in the city center of Diyarbakır, Turkey. Measured electric field levels were plotted on satellite imagery of Diyarbakır and were compared with exposure guidelines published by the International Commission on Non-Ionizing Radiation Protection (ICNIRP). Exposure measurements were performed in dense urban, urban and suburban areas each day for 7 consecutive days. The measurement system consisted of high precision and portable spectrum analyzer, three-axis electric field antenna, connection cable and a laptop which was used to record the measurement samples as a data logger. The highest exposure levels were detected for two places, which are called Diclekent and Batıkent. It was observed that the highest instantaneous electric field strength value for Batıkent was 7.18 V/m and for Diclekent was 5.81 V/m. It was statistically determined that the main contributor band to the total exposure levels was Universal Mobile Telecommunications System band. Finally, it was concluded that all measured exposure levels were lower than the reference levels recommended by ICNIRP for general public health.Journal of Exposure Science and Environmental Epidemiology advance online publication, 2 November 2016; doi:10.1038/jes.2016.64.

  1. Late winter under ice pelagic microbial communities in the high Arctic Ocean and the impact of short-term exposure to elevated CO2 levels

    PubMed Central

    Monier, Adam; Findlay, Helen S.; Charvet, Sophie; Lovejoy, Connie

    2014-01-01

    Polar Oceans are natural CO2 sinks because of the enhanced solubility of CO2 in cold water. The Arctic Ocean is at additional risk of accelerated ocean acidification (OA) because of freshwater inputs from sea ice and rivers, which influence the carbonate system. Winter conditions in the Arctic are of interest because of both cold temperatures and limited CO2 venting to the atmosphere when sea ice is present. Earlier OA experiments on Arctic microbial communities conducted in the absence of ice cover, hinted at shifts in taxa dominance and diversity under lowered pH. The Catlin Arctic Survey provided an opportunity to conduct in situ, under-ice, OA experiments during late Arctic winter. Seawater was collected from under the sea ice off Ellef Ringnes Island, and communities were exposed to three CO2 levels for 6 days. Phylogenetic diversity was greater in the attached fraction compared to the free-living fraction in situ, in the controls and in the treatments. The dominant taxa in all cases were Gammaproteobacteria but acidification had little effect compared to the effects of containment. Phylogenetic net relatedness indices suggested that acidification may have decreased the diversity within some bacterial orders, but overall there was no clear trend. Within the experimental communities, alkalinity best explained the variance among samples and replicates, suggesting subtle changes in the carbonate system need to be considered in such experiments. We conclude that under ice communities have the capacity to respond either by selection or phenotypic plasticity to heightened CO2 levels over the short term. PMID:25324832

  2. Late winter under ice pelagic microbial communities in the high Arctic Ocean and the impact of short-term exposure to elevated CO2 levels.

    PubMed

    Monier, Adam; Findlay, Helen S; Charvet, Sophie; Lovejoy, Connie

    2014-01-01

    Polar Oceans are natural CO2 sinks because of the enhanced solubility of CO2 in cold water. The Arctic Ocean is at additional risk of accelerated ocean acidification (OA) because of freshwater inputs from sea ice and rivers, which influence the carbonate system. Winter conditions in the Arctic are of interest because of both cold temperatures and limited CO2 venting to the atmosphere when sea ice is present. Earlier OA experiments on Arctic microbial communities conducted in the absence of ice cover, hinted at shifts in taxa dominance and diversity under lowered pH. The Catlin Arctic Survey provided an opportunity to conduct in situ, under-ice, OA experiments during late Arctic winter. Seawater was collected from under the sea ice off Ellef Ringnes Island, and communities were exposed to three CO2 levels for 6 days. Phylogenetic diversity was greater in the attached fraction compared to the free-living fraction in situ, in the controls and in the treatments. The dominant taxa in all cases were Gammaproteobacteria but acidification had little effect compared to the effects of containment. Phylogenetic net relatedness indices suggested that acidification may have decreased the diversity within some bacterial orders, but overall there was no clear trend. Within the experimental communities, alkalinity best explained the variance among samples and replicates, suggesting subtle changes in the carbonate system need to be considered in such experiments. We conclude that under ice communities have the capacity to respond either by selection or phenotypic plasticity to heightened CO2 levels over the short term.

  3. Relationship between prenatal lead exposure and infant blood lead levels.

    PubMed

    Archer, Natalie P; Bradford, Carrie M; Klein, David M; Barnes, Jim; Smith, L J; Villanacci, John F

    2012-10-01

    Recent literature has shown that analyzing newborn dried blood spots (DBS) may be effective in assessing some prenatal environmental exposures, such as exposure to lead. The purpose of this study was to evaluate the relationship between prenatal exposure to lead (as measured by newborn DBS results) and blood lead levels (BLLs) in infants 6 months of age or younger, using public health registry data for infants born in Texas from July 2002 through July 2006. The Texas Child Lead Registry (TCLR) was used to identify infants with documented elevated BLLs of 10 μg/dL or higher as well as infants with documented low BLLs. BLLs for these children were compared to their corresponding newborn DBS results using Pearson correlation coefficients and exact logistic regression models. Overall, a significant but weak positive correlation was found between infant BLLs and corresponding newborn DBS lead levels (r = 0.48). However, the odds of an infant with an elevated newborn DBS lead level having an elevated BLL at 6 months of age or younger were much greater than for an infant with a low newborn DBS lead level of <5 μg/dL (adjusted odds ratio 27.95, 95% CI: 5.52-277.28). Although an association was observed between newborn DBS lead levels and BLLs in infants tested between 0 to 6 months of age, our findings suggest that prenatal exposure may not be the only significant source of lead exposure for infants ≤6 months of age.

  4. Population-Level Exposure to Particulate Air Pollution during Active Travel: Planning for Low-Exposure, Health-Promoting Cities

    PubMed Central

    Hankey, Steve; Lindsey, Greg; Marshall, Julian D.

    2016-01-01

    Background: Providing infrastructure and land uses to encourage active travel (i.e., bicycling and walking) are promising strategies for designing health-promoting cities. Population-level exposure to air pollution during active travel is understudied. Objectives: Our goals were a) to investigate population-level patterns in exposure during active travel, based on spatial estimates of bicycle traffic, pedestrian traffic, and particulate concentrations; and b) to assess how those exposure patterns are associated with the built environment. Methods: We employed facility–demand models (active travel) and land use regression models (particulate concentrations) to estimate block-level (n = 13,604) exposure during rush-hour (1600–1800 hours) in Minneapolis, Minnesota. We used the model-derived estimates to identify land use patterns and characteristics of the street network that are health promoting. We also assessed how exposure is correlated with indicators of health disparities (e.g., household income, proportion of nonwhite residents). Our work uses population-level rates of active travel (i.e., traffic flows) rather than the probability of walking or biking (i.e., “walkability” or “bikeability”) to assess exposure. Results: Active travel often occurs on high-traffic streets or near activity centers where particulate concentrations are highest (i.e., 20–42% of active travel occurs on blocks with high population-level exposure). Only 2–3% of blocks (3–8% of total active travel) are “sweet spots” (i.e., high active travel, low particulate concentrations); sweet spots are located a) near but slightly removed from the city-center or b) on off-street trails. We identified 1,721 blocks (~ 20% of local roads) where shifting active travel from high-traffic roads to adjacent low-traffic roads would reduce exposure by ~ 15%. Active travel is correlated with population density, land use mix, open space, and retail area; particulate concentrations were

  5. Maximum exposure levels for xylene, formaldehyde and acetaldehyde in cars.

    PubMed

    Schupp, Thomas; Bolt, Hermann M; Hengstler, Jan G

    2005-01-31

    Although millions of individuals are exposed to emissions from articles inside cars, relatively little has been published about possible adverse health effects and about exposure levels that can be considered safe or "acceptable". Xylene, formaldehyde and acetaldehyde represent typical examples of relevant volatile organic substances (VOC) released from articles inside cars. Recently, a concept for derivation of maximum exposure levels for volatile organic substances in cars has been published. In the present study we applied this concept to derive maximum exposure levels for xylene, formaldehyde and acetaldehyde and compared the resulting concentrations to exposure levels usually found inside of cars. We derived Short Term Exposure Levels Inside Automotive Vehicles (STELIA) of 29, 0.125 and 15.3 mg/m(3) for xylene, formaldehyde and acetaldehyde, respectively. These STELIAs should not be exceeded during short-term exposures, for instance when starting a car that had been heated up during parking in the sun. Exposure Levels Inside Automotive Vehicles (ELIA, chronic) for chronic exposure to non-genotoxic substances were 8.8, 0.125 and 0.635 mg/m(3) for systemic as well as 17.6, 0.125 and 1.7 mg/m(3) for local exposure to xylene, formaldehyde and acetaldehyde, respectively. Although, it is known that exposure limits for carcinogenic substances should be treated with caution, encouraged by the well documented threshold mechanisms we nevertheless derived ELIAs for Carcinogenic and Mutagenic Substances (ELIA, cm) resulting in 0.125 and 0.635 mg/m(3) for formaldehyde and acetaldehyde. If these ELIAs are matched against average concentrations of xylene, formaldehyde and acetaldehyde found in cars at 23 degrees C (1.22, 0.048 and 0.042 mg/m(3)), there is no reason for concern. With respect to STELIAs and extrapolated concentrations at 65 degrees C (14.7, 1.47 and 1.68 mg/m(3), for xylene, formaldehyde and acetaldehyde, respectively), however, a reduction of the

  6. Estimation of Particulate Mass and Manganese Exposure Levels among Welders

    PubMed Central

    Hobson, Angela; Seixas, Noah; Sterling, David; Racette, Brad A.

    2011-01-01

    Background: Welders are frequently exposed to Manganese (Mn), which may increase the risk of neurological impairment. Historical exposure estimates for welding-exposed workers are needed for epidemiological studies evaluating the relationship between welding and neurological or other health outcomes. The objective of this study was to develop and validate a multivariate model to estimate quantitative levels of welding fume exposures based on welding particulate mass and Mn concentrations reported in the published literature. Methods: Articles that described welding particulate and Mn exposures during field welding activities were identified through a comprehensive literature search. Summary measures of exposure and related determinants such as year of sampling, welding process performed, type of ventilation used, degree of enclosure, base metal, and location of sampling filter were extracted from each article. The natural log of the reported arithmetic mean exposure level was used as the dependent variable in model building, while the independent variables included the exposure determinants. Cross-validation was performed to aid in model selection and to evaluate the generalizability of the models. Results: A total of 33 particulate and 27 Mn means were included in the regression analysis. The final model explained 76% of the variability in the mean exposures and included welding process and degree of enclosure as predictors. There was very little change in the explained variability and root mean squared error between the final model and its cross-validation model indicating the final model is robust given the available data. Conclusions: This model may be improved with more detailed exposure determinants; however, the relatively large amount of variance explained by the final model along with the positive generalizability results of the cross-validation increases the confidence that the estimates derived from this model can be used for estimating welder exposures

  7. Validation of Aircraft Noise Models at Lower Levels of Exposure

    NASA Technical Reports Server (NTRS)

    Page, Juliet A.; Plotkin, Kenneth J.; Carey, Jeffrey N.; Bradley, Kevin A.

    1996-01-01

    Noise levels around airports and airbases in the United States arc computed via the FAA's Integrated Noise Model (INM) or the Air Force's NOISEMAP (NMAP) program. These models were originally developed for use in the vicinity of airports, at distances which encompass a day night average sound level in decibels (Ldn) of 65 dB or higher. There is increasing interest in aircraft noise at larger distances from the airport. including en-route noise. To evaluate the applicability of INM and NMAP at larger distances, a measurement program was conducted at a major air carrier airport with monitoring sites located in areas exposed to an Ldn of 55 dB and higher. Automated Radar Terminal System (ARTS) radar tracking data were obtained to provide actual flight parameters and positive identification of aircraft. Flight operations were grouped according to aircraft type. stage length, straight versus curved flight tracks, and arrival versus departure. Sound exposure levels (SEL) were computed at monitoring locations, using the INM, and compared with measured values. While individual overflight SEL data was characterized by a high variance, analysis performed on an energy-averaging basis indicates that INM and similar models can be applied to regions exposed to an Ldn of 55 dB with no loss of reliability.

  8. Personal carbon monoxide exposures of preschool children in Helsinki, Finland: levels and determinants

    NASA Astrophysics Data System (ADS)

    Alm, S.; Mukala, K.; Jantunen, M. J.

    Personal CO exposures of 194 preschool children were measured with personal exposure monitors during a 24 week sampling period from fall 1990 to spring 1991 in Helsinki, Finland. Arithmetic mean of the maximum 1 and 8 h exposure levels were 6.0 and 3.3 mg m -3. The then Finnish ambient air quality guideline values for 1/8 h maximum CO level (30/10 mg m -3) were exceeded in 2/4% of the children's daily maximum 1/8 h exposure levels. Gas stove at home, parents, especially mother, smoking in the home, and living in high rise buildings — reflecting higher local population and traffic density — increased the children's CO exposures. The presence of a fireplace in the home was associated with decreased CO exposures. Father's high education reduced the children's CO exposure while mother's education level had no significant effect. The peak (15 min) exposure levels of the children commuting to day care center by car or bus were higher than those of the children who walked or came by bike.

  9. Inhalation of an essential metal: development of reference exposure levels for manganese.

    PubMed

    Winder, Bruce S; Salmon, Andrew G; Marty, Melanie A

    2010-01-01

    Exposures to high levels of manganese by ingestion or inhalation can damage the central nervous system. However, the capacity of environmental manganese to cause neurotoxicity is of most concern following inhalation exposure. Reference exposure levels (RELs) are values developed by California EPA's Office of Environmental Health Hazard Assessment (OEHHA) to protect the general public from periodic and continual exposures to airborne toxicants. The recently revised guidelines for the development of noncancer RELs encourage the use of benchmark dose methodology where appropriate, and explicitly address the potential susceptibilities associated with early-life exposures (OEHHA, 2008). This paper describes the application of those guidelines to the derivation of RELs to protect the general public from routine 8h and chronic exposures to airborne manganese. The data were amenable to benchmark analysis and the RELs derived reflect the mounting evidence that children represent a population that is differentially susceptible to manganese toxicity. Copyright 2010 Elsevier Inc. All rights reserved.

  10. Noise exposure levels of priests and worshippers in protestant churches.

    PubMed

    Silva, Luiz Felipe; Cabral, Rogério

    2011-01-01

    Context. Worship in Protestant churches in Brazil is very noisy. Thus, this practice may pose a hearing risk. Aims. To evaluate the priests' and worshippers' noise exposure during worship. Settings and design. The analysis was carried out in 5 churches located in the city of São José dos Campos, Brazil. Methods and material. To estimate the worshippers' noise exposure, an author of this study was also submitted to dosimetry. The methodology was based on Fundacentro's Occupational Hygiene Standard No. NHO-01 (2001). Weekly noise exposure was estimated according to the priest's information about the number of services in the period. Results. The priest's noise exposure was over the recommended limits. The normalized exposure level varied between 95.4 to 99.5 dB(A). In 2 of the churches, the noise exposure registered, with values of 85.3 and 86.5 dB(A), may also pose risk to the worshippers. Conclusions. Worship in the churches generated sound pressure levels that imply health risk, especially to priests, so hearing conservation programs with adequate acoustical sanitation measures must be implemented there.

  11. Patient exposure levels in radiotherapy CT simulations in Finland.

    PubMed

    Toroi, P; Kaijaluoto, S; Bly, R

    2015-12-01

    Computed tomography (CT)-based simulation is an essential part of the radiotherapy treatment process. Patient exposure levels in CT simulations were collected from 15 CT systems from all 13 Finnish radiation therapy centres. A large standard deviation up to 56 % in dose levels between CT systems was noticed. Average volumetric CT dose indexes (in body phantom) were 24, 18 and 29 mGy for prostate, resection breast and head and neck treatment targets, respectively, and 70 mGy (in head phantom) for whole brain. These average dose indexes were much higher than those in corresponding diagnostic imaging in Finland. Dose levels in simulations with some devices were even over 3-fold higher than the diagnostic reference level for the same area of interest. Moreover, large variations in other exposure parameters, such as pitch and slice thickness, were seen. The results were discussed nationally, and general guidance to optimise dose levels was shared.

  12. The intersection of aggregate-level lead exposure and crime.

    PubMed

    Boutwell, Brian B; Nelson, Erik J; Emo, Brett; Vaughn, Michael G; Schootman, Mario; Rosenfeld, Richard; Lewis, Roger

    2016-07-01

    Childhood lead exposure has been associated with criminal behavior later in life. The current study aimed to analyze the association between elevated blood lead levels (n=59,645) and crime occurrence (n=90,433) across census tracts within St. Louis, Missouri. Longitudinal ecological study. Saint Louis, Missouri. Blood lead levels. Violent, Non-violent, and total crime at the census tract level. Spatial statistical models were used to account for the spatial autocorrelation of the data. Greater lead exposure at the census-tract level was associated with increased violent, non-violent, and total crime. In addition, we examined whether non-additive effects existed in the data by testing for an interaction between lead exposure and concentrated disadvantage. Some evidence of a negative interaction emerged, however, it failed to reach traditional levels of statistical significance (supplementary models, however, revealed a similar negative interaction that was significant). More precise measurements of lead exposure in the aggregate, produced additional evidence that lead is a potent predictor of criminal outcomes. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. A National Assessment of Sea Level Rise Exposure Using Lidar Elevation Data

    NASA Astrophysics Data System (ADS)

    Strauss, B.; Kulp, S. A.; Tebaldi, C.

    2014-12-01

    The Third National Climate Assessment addressed sea level rise and aggravated coastal flood exposure in all regions, but was completed before high quality lidar-based elevation data became available throughout the entire coastal United States (excluding Alaska). Here we present what we believe to be the first full national assessment incorporating these data. The assessment includes tabulation of land less than 1-6 m above the local high tide line, and of a wide range of features sitting on that land, including total population, socially vulnerable population, housing, property value, road miles, power plants, schools, hospitals, and a wide range of other infrastructure and critical facilities, as well as EPA-listed facilities that are potential sources of contamination during floods or permanent inundation. Tabulations span from zip code to national levels. Notable patterns include the strong concentration of exposure across multiple scales, with a small number of states accounting for most of the total national exposure; and a small number of zip codes accounting for a large proportion of the exposure within many states. Additionally, different features show different exposure patterns; in one example, land and road miles have relatively high exposure but population and property have relatively low exposure in North Carolina. The assessment further places this exposure analysis in the context of localized sea level rise projections integrated with coastal flood risk.

  14. Children exposure to PM levels in a typical school morning

    NASA Astrophysics Data System (ADS)

    Valente, J.; Amorim, J. H.; Cascão, P.; Rodrigues, V.; Borrego, C.

    2012-10-01

    One of the major challenges to urban sustainability is the threat posed by air pollution, being exposure to ambient air pollutants associated with a high rate of premature deaths. Therefore, the study of the exposure of people, and in particular of vulnerable population groups such as children, to air pollution is a subject of paramount importance. In this paper a CFD model is used to simulate the particulate matter personal exposure of students in their school routine (both daily walk to and permanence in school). Under the concept of COST TU0801, the usability of a 3D city model is evaluated. The analysis was carried out for 4 children, with 4 alternative walking routes to school and using 4 different classrooms. Results indicate that the individual exposure of children is extremely spatially dependent, as a consequence of the wind flow and air pollutant dispersion patterns.

  15. 30 CFR 57.5042 - Revised exposure levels.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Revised exposure levels. 57.5042 Section 57.5042 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Air Quality...

  16. Noise exposure levels in stock car auto racing.

    PubMed

    Rose, Austin S; Ebert, Charles S; Prazma, Jiri; Pillsbury, Harold C

    2008-12-01

    Noise-induced hearing loss associated with the workplace has been well described. Far less is known, however, about the risks to hearing from recreational sources of noise. We investigated the popular sport of stock car racing as a potentially significant source of noise exposure, and we conducted a sound-level survey at a National Association for Stock Car Auto Racing (NASCAR) event. Noise levels measured during the race ranged from 96.5 to 104 dB(A) at 46 meters ( approximately 150 feet) from the track and 99 to 109 dB(A) at 6 meters ( approximately 20 feet) from the track. The peak sound pressure level at 6 meters was 109 dB(A). Although significantly less than that associated with an immediate permanent threshold shift, such an exposure could cause a temporary threshold shift. Alhough hearing protection is recommended, particularly for track employees with longer periods of exposure, racing fans with only occasional exposure to such noise levels are unlikely to develop a permanent noise-induced hearing loss.

  17. 30 CFR 57.5042 - Revised exposure levels.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Revised exposure levels. 57.5042 Section 57.5042 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Air Quality...

  18. Televised Antismoking Advertising: Effects of Level and Duration of Exposure

    PubMed Central

    Cotter, Trish; Perez, Donna; Wakefield, Melanie

    2013-01-01

    Objectives. We assessed the effects of levels and duration of exposure to televised antismoking advertising on cognitive and behavioral changes. Methods. We used data from a serial cross-sectional telephone survey with weekly interviews of adult smokers and recent quitters in New South Wales, Australia (n = 13 301), between April 2005 and December 2010. We merged survey data with commercial TV ratings data to estimate individuals’ exposure to antismoking advertising. Results. Logistic regression analyses indicated that after adjustment for a wide range of potential confounders, exposure to antismoking advertising at levels between 100 and 200 gross rating points per week on average over 6 to 9 weeks was associated with an increased likelihood of having (1) salient quitting thoughts and (2) recent quit attempts. Associations between exposure for shorter periods and these outcomes were not significant. Conclusions. Broadcasting schedules may affect the success of antismoking ads. Campaign planners should ensure advertising exposure at adequate frequency over relatively sustained periods to maximize impact. PMID:23763419

  19. Estimating long-term exposure levels in process-type industries using production rates.

    PubMed

    Kalliokoski, P

    1990-06-01

    Exposure to toluene in two publication rotogravure plants was investigated to examine how accurately long-term exposure can be estimated on the basis of production rate. Toluene consumption was used as the measure of production rate. Continuous area monitoring was used to find a correlation between production rate and airborne level of toluene. Workers' exposure levels were first estimated by combining data on toluene concentrations in various monitoring sites with data supplied by the workers on the time spent in these areas. These calculated exposure levels were found to correlate well with the actual exposure levels obtained by breathing zone sampling. There was also a fairly high correlation between the concentration of toluene in front of the press and the consumption of toluene if the process conditions remained stable. It was, however, necessary to investigate this association separately for the situations where the degree of enclosure of the press or number of emission sources were unusual or when the workers stayed in the control rooms, which were separated from the other pressroom areas. A reasonably high correlation between the variables of the main interest, that is, the calculated toluene exposures and the consumption of toluene, was found in one of the plants investigated, whereas this correlation was low in the other plant. Even though this kind of estimation procedure does not always lead to accurate exposure levels, it helps in understanding how those are affected by the process parameters.

  20. Do ambient noise exposure levels predict hearing loss in a modern industrial cohort?

    PubMed

    Rabinowitz, P M; Galusha, D; Dixon-Ernst, C; Slade, M D; Cullen, M R

    2007-01-01

    Much of what is known about the exposure-response relationship between occupational noise exposures and hearing loss comes from cross-sectional studies conducted before the widespread implementation of workplace hearing conservation programmes. Little is known about the current relationship of ambient noise exposure measurements to hearing loss risk. To examine the relationship between rates of high frequency hearing loss and measured levels of noise exposure in a modern industrial workforce. Ten-year hearing loss rates were determined for 6217 employees of an aluminium manufacturing company. Industrial hygiene and human resources records allowed for reconstruction of individual noise exposures. Hearing loss rates were compared to ANSI 3.44 predictions based on age and noise exposure. Associations between hearing loss, noise exposure, and covariate risk factors were assessed using multivariate regression. Workers in higher ambient noise jobs tended to experience less high frequency hearing loss than co-workers exposed at lower noise levels. This trend was also seen in stratified analyses of white males and non-hunters. At higher noise exposure levels, the magnitude of hearing loss was less than predicted by ANSI 3.44 formulae. There was no indication that a healthy worker effect could explain these findings. The majority of 10 dB standard threshold shifts (STS) occurred in workers whose calculated ambient noise exposures were less than or equal to 85 dBA. In this modern industrial cohort, hearing conservation efforts appear to be reducing hearing loss rates, especially at higher ambient noise levels. This could be related to differential use of hearing protection. The greatest burden of preventable occupational hearing loss was found in workers whose noise exposure averaged 85 dBA or less. To further reduce rates of occupational hearing loss, hearing conservation programmes may require innovative approaches targeting workers with noise exposures close to 85 dBA.

  1. Estimation of exposure distribution adjusting for association between exposure level and detection limit.

    PubMed

    Yang, Yuchen; Shelton, Brent J; Tucker, Thomas T; Li, Li; Kryscio, Richard; Chen, Li

    2017-08-15

    In environmental exposure studies, it is common to observe a portion of exposure measurements to fall below experimentally determined detection limits (DLs). The reverse Kaplan-Meier estimator, which mimics the well-known Kaplan-Meier estimator for right-censored survival data with the scale reversed, has been recommended for estimating the exposure distribution for the data subject to DLs because it does not require any distributional assumption. However, the reverse Kaplan-Meier estimator requires the independence assumption between the exposure level and DL and can lead to biased results when this assumption is violated. We propose a kernel-smoothed nonparametric estimator for the exposure distribution without imposing any independence assumption between the exposure level and DL. We show that the proposed estimator is consistent and asymptotically normal. Simulation studies demonstrate that the proposed estimator performs well in practical situations. A colon cancer study is provided for illustration. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  2. Radiofrequency exposure near high-voltage lines.

    PubMed Central

    Vignati, M; Giuliani, L

    1997-01-01

    Many epidemiologic studies suggest a relationship between incidence of diseases like cancer and leukemia and exposure to 50/60 Hz magnetic fields. Some studies suggest a relationship between leukemia incidence in populations residing near high-voltage lines and the distance to these lines. Other epidemiologic studies suggest a relationship between leukemia incidence and exposure to 50/60 Hz magnetic fields (measured or estimated) and distance from the main system (220 or 120 V). The present work does not question these results but is intended to draw attention to a possible concurrent cause that might also increase the incidence of this disease; the presence on an electric grid of radiofrequency currents used for communications and remote control. These currents have been detected on high- and medium-voltage lines. In some cases they are even used on the main system for remote reading of electric meters. This implies that radiofrequency (RF) magnetic fields are present near the electric network in addition to the 50/60 Hz fields. This intensity of these RF fields is low but the intensity of currents induced in the human body by exposure to magnetic fields increases with frequency. Because scientific research has not yet clarified whether the risk is related to the value of magnetic induction or to the currents this kind of exposure produces in the human body, it is reasonable to suggest that the presence of the RF magnetic fields must be considered in the context of epidemiologic studies. Images Figure 3. Figure 4. Figure 5. PMID:9467084

  3. Population-Level Exposure to Particulate Air Pollution during Active Travel: Planning for Low-Exposure, Health-Promoting Cities.

    PubMed

    Hankey, Steve; Lindsey, Greg; Marshall, Julian D

    2017-04-01

    Providing infrastructure and land uses to encourage active travel (i.e., bicycling and walking) are promising strategies for designing health-promoting cities. Population-level exposure to air pollution during active travel is understudied. Our goals were a) to investigate population-level patterns in exposure during active travel, based on spatial estimates of bicycle traffic, pedestrian traffic, and particulate concentrations; and b) to assess how those exposure patterns are associated with the built environment. We employed facility-demand models (active travel) and land use regression models (particulate concentrations) to estimate block-level (n = 13,604) exposure during rush-hour (1600-1800 hours) in Minneapolis, Minnesota. We used the model-derived estimates to identify land use patterns and characteristics of the street network that are health promoting. We also assessed how exposure is correlated with indicators of health disparities (e.g., household income, proportion of nonwhite residents). Our work uses population-level rates of active travel (i.e., traffic flows) rather than the probability of walking or biking (i.e., "walkability" or "bikeability") to assess exposure. Active travel often occurs on high-traffic streets or near activity centers where particulate concentrations are highest (i.e., 20-42% of active travel occurs on blocks with high population-level exposure). Only 2-3% of blocks (3-8% of total active travel) are "sweet spots" (i.e., high active travel, low particulate concentrations); sweet spots are located a) near but slightly removed from the city-center or b) on off-street trails. We identified 1,721 blocks (~ 20% of local roads) where shifting active travel from high-traffic roads to adjacent low-traffic roads would reduce exposure by ~ 15%. Active travel is correlated with population density, land use mix, open space, and retail area; particulate concentrations were mostly unchanged with land use. Public health officials and urban

  4. PCDD and PCDF exposure and levels in humans in Germany.

    PubMed Central

    Beck, H; Dross, A; Mathar, W

    1994-01-01

    For nonoccupationally exposed persons, the daily intake via food consumption has been calculated to be 0.35 pg/kg body weight per day for 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and 2.3 pg/kg body weight per day for TCDD equivalents (TEqs). As compared to food, other sources and pathways are of minor importance. Food of animal origin contributes most, although human exposure begins with atmospheric emissions depositing these compounds on plant surfaces. In the meantime, a possible additional body burden from cardboard containers for cow's milk and coffee filters has been practically excluded. Of the 210 existing PCDDs and PCDFs, only 15 2,3,7,8-substituted isomers with a characteristic congener pattern can be found in samples of human origin. In adipose tissue and milk samples, mean levels for 2,3,7,8-TCDD of 7.2 and 3.6 pg/g fat, respectively, and of 56 (range 18-122) and 30 (range 10-72) pg TEqs/g fat, respectively, were determined. Human data revealed a dependency of polychlorinated dibenzo-p-dioxins/polychlorinated dibenzofurans (PCDD/PCDF) levels on age. In human milk, levels became reduced with the number of children born to mothers and duration of breast-feeding period. The average daily intake for a breast-fed child has been calculated to be 17 pg 2,3,7,8-TCDD/kg body weight per day and 142 pg TEqs/kg body weight per day, respectively. Levels in adipose tissue of infants, even if breast fed, were distinctly lower compared to human milk. In human milk, adipose tissue, and whole blood, PCDD/PCDF concentrations have been found to be equal on a fat-weight basis. Liver fat accumulated PCDD/PCDF with an alteration in the congener distribution pattern, whereas brain, even on a fat-weight basis, showed the lowest concentrations. Elevated or even high levels were found in occupationally exposed persons working in special chemical plants or involved in specific processes. There are limited data suggesting slightly elevated PCDD/PCDF levels are due to long

  5. Occupational exposure to diesel engine exhaust and serum cytokine levels.

    PubMed

    Dai, Yufei; Ren, Dianzhi; Bassig, Bryan A; Vermeulen, Roel; Hu, Wei; Niu, Yong; Duan, Huawei; Ye, Meng; Meng, Tao; Xu, Jun; Bin, Ping; Shen, Meili; Yang, Jufang; Fu, Wei; Meliefste, Kees; Silverman, Debra; Rothman, Nathaniel; Lan, Qing; Zheng, Yuxin

    2017-10-12

    The International Agency for Research on Cancer has classified diesel engine exhaust (DEE) as a human lung carcinogen. Given that inflammation is suspected to be an important underlying mechanism of lung carcinogenesis, we evaluated the relationship between DEE exposure and the inflammatory response using data from a cross-sectional molecular epidemiology study of 41 diesel engine testing workers and 46 unexposed controls. Repeated personal exposure measurements of PM2.5 and other DEE constituents were taken for the diesel engine testing workers before blood collection. Serum levels of six inflammatory biomarkers including interleukin (IL)-1, IL-6, IL-8, tumor necrosis factor (TNF)-α, macrophage inflammatory protein (MIP)-1β, and monocyte chemotactic protein (MCP)-1 were analyzed in all subjects. Compared to unexposed controls, concentrations of MIP-1β were significantly reduced by ∼37% in DEE exposed workers (P < 0.001) and showed a strong decreasing trend with increasing PM2.5 concentrations in all subjects (Ptrend  < 0.001) as well as in exposed subjects only (Ptrend  = 0.001). Levels of IL-8 and MIP-1β were significantly lower in workers in the highest exposure tertile of PM2.5 (>397 µg/m(3) ) compared to unexposed controls. Further, significant inverse exposure-response relationships for IL-8 and MCP-1 were also found in relation to increasing PM2.5 levels among the DEE exposed workers. Given that IL-8, MIP-1β, and MCP-1 are chemokines that play important roles in recruitment of immunocompetent cells for immune defense and tumor cell clearance, the observed lower levels of these markers with increasing PM2.5 exposure may provide insight into the mechanism by which DEE promotes lung cancer. Environ. Mol. Mutagen., 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  6. Mercury Exposure Levels in Children with Dental Amalgam Fillings

    PubMed Central

    Miriam Varkey, Indu; Shetty, Rajmohan; Hegde, Amitha

    2014-01-01

    ABSTRACT% Objectives: Mercury combined with other metals to form solid amalgams has long been used in reconstructive dentistry but its use has been controversial since at least the middle of the 19th century. The exposure and body burden of mercury reviews have consistently stated that there is a deficiency of adequate epidemiological studies addressing this issue. Fish and dental amalgam are two major sources of human exposure to organic (MeHg) and inorganic Hg respectively. Materials and methods: A total of 150 subjects aged between 9 and 14 years were divided into two groups of 75 subjects each depending on their diet, i.e. seafood or nonseafood consuming. Each category was subdivided into three groups based on number of restorations. Scalp hair and urine samples were collected at baseline and 3 months later to assess the organic and inorganic levels of mercury respectively by atomic absorption spectrophotometer (AAS). Results: The mean values of urinary mercury (inorganic mercury) in the group of children with restorations were 1.5915 μg/l as compared to 0.0130 μg/l in the groups with no amalgam restorations (p < 0.001) (Wilcoxon sign rank test and paired t-test). The hair mercury levels (organic mercury) varied signi-ficantly between the fsh-eating group and nonfsh-eating group, the average values being 1.03 μg/l and 0.84 μg/l respectively (p < 0.001) (Mann-Whitney U-test and paired t-test). Conclusion and significance: The notion about the mercury being released from the amalgam restorations as a sole exposure source needs to be put to a rest, as environmental factors collectively overpower the exposure levels from restorations alone. How to cite this article: Varkey IM, Shetty R, Hegde A. Mercury Exposure Levels in Children with Dental Amalgam Fillings. Int J Clin Pediatr Dent 2014;7(3):180-185. PMID:25709298

  7. High pressure liquid level monitor

    DOEpatents

    Bean, Vern E.; Long, Frederick G.

    1984-01-01

    A liquid level monitor for tracking the level of a coal slurry in a high-pressure vessel including a toroidal-shaped float with magnetically permeable bands thereon disposed within the vessel, two pairs of magnetic field generators and detectors disposed outside the vessel adjacent the top and bottom thereof and magnetically coupled to the magnetically permeable bands on the float, and signal processing circuitry for combining signals from the top and bottom detectors for generating a monotonically increasing analog control signal which is a function of liquid level. The control signal may be utilized to operate high-pressure control valves associated with processes in which the high-pressure vessel is used.

  8. Permissible Exposure Level for Lunar Dusts: Gaps are Closing

    NASA Technical Reports Server (NTRS)

    James, John T.; Lam, Chiu-Wing; Scully Robert; Santana, Patricia; Cooper, Bonnie; McKay, David; Zeidler-Erdely, Patti C.; Castranova, Vincent

    2010-01-01

    Space faring nations plan to return human explorers to the moon within the next decade. Experience during the Apollo flights suggests that lunar dust will invariably get into the habitat where the finest portion (less than 5 micrometers) could be inhaled by the crew before it is cleared from the atmosphere. NASA is developing a database from which a 6-month, episodic exposure standard for lunar dust can be set. Three kinds of moon dust were prepared from a parent sample of Apollo 14 regolith #14003,96. Our goal was to prepare each type of dust sample with a mean diameter less than 2 m, which is suitable for instillation into the lungs of rats. The three samples were prepared as follows: separation from the parent sample using a fluidized bed, grinding using a jet mill grinder, or grinding with a ball-mill grinder. Grinding simulated restoration of surface activation of dust expected to occur at the surface of the moon on native lunar dust. We used two grinding methods because they seemed to produce different modes of activation. The effects of grinding were preserved by maintaining the dust in ultra-pure nitrogen until immediately before it was placed in suspension for administration to rats. The dust was suspended in physiological saline with 10% Survanta, a lung surfactant. Rats were given intratrachael instillations of the dust suspension at three doses. In addition to the three moon dusts (A, C and E), we instilled the same amount of a negative control (TiO2, B) and a highly-toxic, positive control (quartz, D). These additional mineral dusts were selected because they have well-established and very different permissible exposure levels (PELs). Our goal was to determine where lunar dusts fit between these extremes, and then estimate a PEL for each lunar dust. We evaluated many indices of toxicity to the lung. The figure shows the changes in lactate dehydrogenase (LDH), a marker of cell death, for the five dusts. Benchmark dose software (Version 2.1.2) from the

  9. Chronic exposure to environmental levels of tribromophenol impairs zebrafish reproduction

    SciTech Connect

    Deng Jun; Liu Chunsheng; Yu Liqin; Zhou Bingsheng

    2010-02-15

    Tribromophenol (2,4,6-TBP) is ubiquitously found in aquatic environments and biota. In this study, we exposed zebrafish embryos (F{sub 0}; 2'''' days post-fertilization, dpf) to environmental concentration (0.3 mug/L) and a higher concentration (3.0 mug/L) of TBP and assessed the impact of chronic exposure (120 dpf) on reproduction. TBP exposure did not cause a significant increase in the malformation and reduction in the survival in the F{sub 0}-generation fish. After TBP exposure, the plasma testosterone and estradiol levels significantly increased in males and decreased in females. The transcription of steroidogenic genes (3beta-HSD, 17beta-HSD, CYP17, CYP19A, CYP19B) was significantly upregulated in the brain and testes in males and downregulated in the brain and ovary in females. TBP exposure significantly downregulated and upregulated the expression of VTG in the liver of female and male fish, respectively. Meanwhile, TBP exposure altered the sex ratio toward a male-dominant state. The F{sub 1}-generation larvae exhibited increased malformation, reduced survival, and retarded growth, suggesting that TBP in the aquatic environment has significant adverse effects on fish population.

  10. Pulmonary biochemical and histological alterations after repeated low-level blast overpressure exposures.

    PubMed

    Elsayed, Nabil M; Gorbunov, Nikolai V

    2007-01-01

    Blast overpressure (BOP), also known as high energy impulse noise, is a damaging outcome of explosive detonations and firing of weapons. Exposure to BOP shock waves alone results in injury predominantly to the hollow organ systems such as auditory, respiratory, and gastrointestinal systems. In recent years, the hazards of BOP that once were confined to military and professional settings have become a global societal problem as terrorist bombings and armed conflicts involving both military and civilian populations increased significantly. We have previously investigated the effects of single BOP exposures at different peak pressures. In this study, we examined the effects of repeated exposure to a low-level BOP and whether the number of exposures or time after exposure would alter the injury outcome. We exposed deeply anesthetized rats to simulated BOP at 62 +/- 2 kPa peak pressure. The lungs were examined immediately after one exposure (1 + 0), or 1 h after one (1 + 1), two (2 + 1), or three (3 + 1) consecutive exposures at 3-min interval. In one group of animals, we examined the effects of repeated exposure on lung weight, methemoglobin, transferrin, antioxidants, and lipid peroxidation. In a second group, the lungs were fixed inflated at 25 cm water, sectioned, and examined histologically after one to three repeated exposures, or after one exposure at 1, 6, and 24 h. We found that single BOP exposure causes notable changes after 1 h, and that repeating BOP exposure did not add markedly to the effect of the first one. However, the effects increased significantly with time from 1 to 24 h. These observations have biological and occupational implications, and emphasize the need for protection from low-level BOP, and for prompt treatment within the first hour following BOP exposure.

  11. Bacillus thermoamylovorans Spores with Very-High-Level Heat Resistance Germinate Poorly in Rich Medium despite the Presence of ger Clusters but Efficiently upon Exposure to Calcium-Dipicolinic Acid

    PubMed Central

    Berendsen, Erwin M.; Krawczyk, Antonina O.; Klaus, Verena; de Jong, Anne; Boekhorst, Jos; Eijlander, Robyn T.

    2015-01-01

    High-level heat resistance of spores of Bacillus thermoamylovorans poses challenges to the food industry, as industrial sterilization processes may not inactivate such spores, resulting in food spoilage upon germination and outgrowth. In this study, the germination and heat resistance properties of spores of four food-spoiling isolates were determined. Flow cytometry counts of spores were much higher than their counts on rich medium (maximum, 5%). Microscopic analysis revealed inefficient nutrient-induced germination of spores of all four isolates despite the presence of most known germination-related genes, including two operons encoding nutrient germinant receptors (GRs), in their genomes. In contrast, exposure to nonnutrient germinant calcium-dipicolinic acid (Ca-DPA) resulted in efficient (50 to 98%) spore germination. All four strains harbored cwlJ and gerQ genes, which are known to be essential for Ca-DPA-induced germination in Bacillus subtilis. When determining spore survival upon heating, low viable counts can be due to spore inactivation and an inability to germinate. To dissect these two phenomena, the recoveries of spores upon heat treatment were determined on plates with and without preexposure to Ca-DPA. The high-level heat resistance of spores as observed in this study (D120°C, 1.9 ± 0.2 and 1.3 ± 0.1 min; z value, 12.2 ± 1.8°C) is in line with survival of sterilization processes in the food industry. The recovery of B. thermoamylovorans spores can be improved via nonnutrient germination, thereby avoiding gross underestimation of their levels in food ingredients. PMID:26341201

  12. Bacillus thermoamylovorans Spores with Very-High-Level Heat Resistance Germinate Poorly in Rich Medium despite the Presence of ger Clusters but Efficiently upon Exposure to Calcium-Dipicolinic Acid.

    PubMed

    Berendsen, Erwin M; Krawczyk, Antonina O; Klaus, Verena; de Jong, Anne; Boekhorst, Jos; Eijlander, Robyn T; Kuipers, Oscar P; Wells-Bennik, Marjon H J

    2015-11-01

    High-level heat resistance of spores of Bacillus thermoamylovorans poses challenges to the food industry, as industrial sterilization processes may not inactivate such spores, resulting in food spoilage upon germination and outgrowth. In this study, the germination and heat resistance properties of spores of four food-spoiling isolates were determined. Flow cytometry counts of spores were much higher than their counts on rich medium (maximum, 5%). Microscopic analysis revealed inefficient nutrient-induced germination of spores of all four isolates despite the presence of most known germination-related genes, including two operons encoding nutrient germinant receptors (GRs), in their genomes. In contrast, exposure to nonnutrient germinant calcium-dipicolinic acid (Ca-DPA) resulted in efficient (50 to 98%) spore germination. All four strains harbored cwlJ and gerQ genes, which are known to be essential for Ca-DPA-induced germination in Bacillus subtilis. When determining spore survival upon heating, low viable counts can be due to spore inactivation and an inability to germinate. To dissect these two phenomena, the recoveries of spores upon heat treatment were determined on plates with and without preexposure to Ca-DPA. The high-level heat resistance of spores as observed in this study (D120°C, 1.9 ± 0.2 and 1.3 ± 0.1 min; z value, 12.2 ± 1.8°C) is in line with survival of sterilization processes in the food industry. The recovery of B. thermoamylovorans spores can be improved via nonnutrient germination, thereby avoiding gross underestimation of their levels in food ingredients. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  13. [Lead exposure of people living in a lead high exposure area from local diet].

    PubMed

    Zhou, Yong; He, Liping; Huang, Xiao; He, Junshan

    2011-11-01

    To study the lead exposure of people living in a lead high exposure area from local diet, and to assess its health risks. Thirty five subjects were selected by random from a mining area and another 30 subjects were selected from a non-polluted area. The exposure of lead was estimated by the content of lead in drinking water and vegetables, and health risks was estimated by the levels of lead in blood and urine. The content of lead in drinking water and vegetables in the mining area was 20.6 microg/L and 1.61mg/kg (geometric mean) respectively, which were higher than that in the unpolluted area (6.0 microg/L and 0.56 mg/kg, geometric mean) (P < 0.01). The daily lead exposure of male and female inhabitants in the mining area from diet was 16.88 microg/kg and 16.09 microg/kg respectively, which was higher than that in the unpolluted area (P < 0.01), but the sex difference was not significant statistically (P > 0.05). Blood lead and urine lead of inhabitants in the mining-area were higher than those in the unpolluted area. The health risks for male and female inhabitants in the mining area were 4.73 and 4.51. The health risks of lead exposure caused by diet (drinking water and food) were relatively high in the mining area.

  14. Understanding molecular-level effects during post-exposure processing

    NASA Astrophysics Data System (ADS)

    Schmid, Gerard M.; Smith, Mark D.; Mack, Chris A.; Singh, Vivek K.; Burns, Sean D.; Willson, C. Grant

    2001-08-01

    The perpetual advancement of materials and equipment for microlithography has resulted in reduction of critical dimensions to scales approaching the size of the molecules that constitute a photoresist. As a result, molecular scale effects such as line edge roughness have become an increasing concern for resist manufacturers and process engineers alike. Computer simulation of lithography has become an integral tool for both process optimization and development of new technologies. However, these simulation tools are generally based upon continuum approximation of the resist material, and are therefore unable to investigate molecular level variations. In this work we investigate the increasing importance of molecular level effects, especially in terms of the contributions of the post exposure bake (PEB) to feature roughness. A linkage has been made between a previously reported mesoscale simulation of the post exposure bake. The mesoscale simulation models discrete transport and reaction events during the post exposure bake to determine solubility variations on the scale of a single oligomeric chain. These solubility variations are then imported into PROLITH and transformed into photoresist topography using the familiar Mack dissolution model. This method has been used to simulate line-edge formation in an APEX-type resist. It is found that the distribution of photoproducts produced during exposure can lead to significant solubility variations during the PEB. These solubility variations can become manifest as roughness of resist feature topogrpahy.

  15. Do ambient noise exposure levels predict hearing loss in a modern industrial cohort?

    PubMed Central

    Rabinowitz, P M; Galusha, D; Dixon‐Ernst, C; Slade, M D; Cullen, M R

    2007-01-01

    Background Much of what is known about the exposure–response relationship between occupational noise exposures and hearing loss comes from cross‐sectional studies conducted before the widespread implementation of workplace hearing conservation programmes. Little is known about the current relationship of ambient noise exposure measurements to hearing loss risk. Aim To examine the relationship between rates of high frequency hearing loss and measured levels of noise exposure in a modern industrial workforce. Methods Ten‐year hearing loss rates were determined for 6217 employees of an aluminium manufacturing company. Industrial hygiene and human resources records allowed for reconstruction of individual noise exposures. Hearing loss rates were compared to ANSI 3.44 predictions based on age and noise exposure. Associations between hearing loss, noise exposure, and covariate risk factors were assessed using multivariate regression. Results Workers in higher ambient noise jobs tended to experience less high frequency hearing loss than co‐workers exposed at lower noise levels. This trend was also seen in stratified analyses of white males and non‐hunters. At higher noise exposure levels, the magnitude of hearing loss was less than predicted by ANSI 3.44 formulae. There was no indication that a healthy worker effect could explain these findings. The majority of 10 dB standard threshold shifts (STS) occurred in workers whose calculated ambient noise exposures were less than or equal to 85 dBA. Conclusions In this modern industrial cohort, hearing conservation efforts appear to be reducing hearing loss rates, especially at higher ambient noise levels. This could be related to differential use of hearing protection. The greatest burden of preventable occupational hearing loss was found in workers whose noise exposure averaged 85 dBA or less. To further reduce rates of occupational hearing loss, hearing conservation programmes may require innovative approaches

  16. Radiation-induced taste aversion: effects of radiation exposure level and the exposure-taste interval

    SciTech Connect

    Spector, A.C.; Smith, J.C.; Hollander, G.R.

    1986-05-01

    Radiation-induced taste aversion has been suggested to possibly play a role in the dietary difficulties observed in some radiotherapy patients. In rats, these aversions can still be formed even when the radiation exposure precedes the taste experience by several hours. This study was conducted to examine whether increasing the radiation exposure level could extend the range of the exposure-taste interval that would still support the formation of a taste aversion. Separate groups of rats received either a 100 or 300 R gamma-ray exposure followed 1, 3, 6, or 24 h later by a 10-min saccharin (0.1% w/v) presentation. A control group received a sham exposure followed 1 h later by a 10-min saccharin presentation. Twenty-four hours following the saccharin presentation all rats received a series of twelve 23-h two-bottle preference tests between saccharin and water. The results indicated that the duration of the exposure-taste interval plays an increasingly more important role in determining the initial extent of the aversion as the dose decreases. The course of recovery from taste aversion seems more affected by dose than by the temporal parameters of the conditioning trial.

  17. High-Level Radioactive Waste.

    ERIC Educational Resources Information Center

    Hayden, Howard C.

    1995-01-01

    Presents a method to calculate the amount of high-level radioactive waste by taking into consideration the following factors: the fission process that yields the waste, identification of the waste, the energy required to run a 1-GWe plant for one year, and the uranium mass required to produce that energy. Briefly discusses waste disposal and…

  18. High-Level Radioactive Waste.

    ERIC Educational Resources Information Center

    Hayden, Howard C.

    1995-01-01

    Presents a method to calculate the amount of high-level radioactive waste by taking into consideration the following factors: the fission process that yields the waste, identification of the waste, the energy required to run a 1-GWe plant for one year, and the uranium mass required to produce that energy. Briefly discusses waste disposal and…

  19. The Relations between Polycyclic Aromatic Hydrocarbons Exposure and 1-OHP Levels as a Biomarker of the Exposure.

    PubMed

    Klöslová, Zuzana; Drímal, Marek; Balog, Karol; Koppová, Kvetoslava; Dubajová, Jarmila

    2016-12-01

    Polycyclic aromatic hydrocarbons (PAHs) are the products of incomplete combustion or pyrolysis of various organic materials. Their ubiquity in the environment leads to measurable levels of exposure. However, the exposure varies strongly between different regions in Europe. Some PAHs with four or more rings are suspected to be human carcinogens. Therefore, the occupational and/or environmental exposure to PAHs may cause a significant health risk. The aim of the study was to evaluate current levels of PAH exposure in defined groups of workers. The industrial sites selected in this survey involved PAHs originating from coal tar pitch, carbon black, bitumen, and rubber fumes. Based on the historical data, the sites were expected to exhibit quantifiable levels of exposure to PAHs. The total study population consisted of 139 persons: 108 workers (85 males and 23 females) workers were occupationally exposed in aluminium production, the production of graphite electrodes, road construction, or the rubber forming industry and 31 control individuals in two groups. The highest concentrations – 8-hour time-weighted average (TWA) levels (sum of 16 components according to the EPA list), as expected, were found in the aluminium production plant (55.15 µg.m(−3)) and production of graphite electrodes (54.25 µg.m(−3)). The lowest concentrations were found in personal air samples of road construction workers (1.93 µg.m(−3)). The concentrations of 1-hydroxypyrene as a pyrene metabolite (1-OHP) in the urine of the exposed group of workers were found in levels 0.74 µmol.mol(−1) creatinine before the exposure and 2.27 µmol.mol(−1) creatinine after the exposure (arithmetic mean values). 1-OHP concentrations in post-shift urine samples were highly correlated with the total airborne PAHs concentrations and pyrene concentrations in air. The correlation coefficients (rS) between 1-OHP concentration and pyrene or total PAHs in air were 0.710 and 0.752 (p < 0.05). This

  20. Health effects of low-level exposure to formaldehyde

    SciTech Connect

    Main, D.M.; Hogan, T.J.

    1983-12-01

    Twenty-one subjects exposed to formaldehyde (at levels between 0.12 and 1.6 parts per million (ppm)) in two mobile trailers and the remaining 18 unexposed workers of the same workforce were examined by questionnaire and spirometry. Symptoms of eye and throat irritation and increased headache and fatigue were significantly more common among the exposed group than the comparison group. Irritation of the nose, chest tightness, and shortness of breath were also more common among the exposed. Spirometry revealed no decrease in ventilatory function among the exposed workers. The significant increase in frequency of individuals with symptoms indicated an adverse health effect from exposure to formaldehyde at levels between 0.12 and 1.6 ppm. This may have implications regarding the adequacy of the US permissable exposure limit value and suggest the need for further examination of the health effects of formaldehyde in the nonoccupational environment.

  1. The CMS High Level Trigger

    NASA Astrophysics Data System (ADS)

    Trocino, Daniele

    2014-06-01

    The CMS experiment has been designed with a two-level trigger system: the Level-1 Trigger, implemented in custom-designed electronics, and the High-Level Trigger (HLT), a streamlined version of the CMS offline reconstruction software running on a computer farm. A software trigger system requires a tradeoff between the complexity of the algorithms running with the available computing power, the sustainable output rate, and the selection efficiency. We present the performance of the main triggers used during the 2012 data taking, ranging from simple single-object selections to more complex algorithms combining different objects, and applying analysis-level reconstruction and selection. We discuss the optimisation of the trigger and the specific techniques to cope with the increasing LHC pile-up, reducing its impact on the physics performance.

  2. [Survey of noise exposure level of national forestry workers].

    PubMed

    Taoda, K; Watanabe, S; Nishiyama, K; Fukuchi, Y; Miyakita, T

    1998-05-01

    Eighty-one national forestry workers who were using chain saws, log cutters, log cutting machines, bush cleaners, timber-collecting cable machines and forklifts were examined for their level of noise exposure in a working day by using a portable sound meter. And their noise exposure levels Leq (8 h) for a year were estimated based on the measured noise levels and on the number of noise exposure days and hours in a year recorded in their work documents. The survey was made from July to December, 1988. The maximum noise levels with all the machines except a case of the forklift were above 100 dB, and with most chain saws they were above 110 dB. The amount of time that workers were exposed to the noise of logging and lumbering with chain saws, cutting by bush cleaners and timber-collecting cable machines without a cabin was longer than the allowable time for 90 dB and 95 dB. The number of noise exposure days in a year is fewer than reported in the past. The estimated Leq (8 h) for 32 out of 34 lumbermen surveyed was more than 85 dB, and for 5 lumbermen the Leq (8 h) was more than 90 dB. From these results, it can be concluded that there is a danger of noise induced hearing loss in national forestry workers using chain saws, log cutters, log cutting machines and timber-collecting cable machines without a cabin in 1987.

  3. RPython high-level synthesis

    NASA Astrophysics Data System (ADS)

    Cieszewski, Radoslaw; Linczuk, Maciej

    2016-09-01

    The development of FPGA technology and the increasing complexity of applications in recent decades have forced compilers to move to higher abstraction levels. Compilers interprets an algorithmic description of a desired behavior written in High-Level Languages (HLLs) and translate it to Hardware Description Languages (HDLs). This paper presents a RPython based High-Level synthesis (HLS) compiler. The compiler get the configuration parameters and map RPython program to VHDL. Then, VHDL code can be used to program FPGA chips. In comparison of other technologies usage, FPGAs have the potential to achieve far greater performance than software as a result of omitting the fetch-decode-execute operations of General Purpose Processors (GPUs), and introduce more parallel computation. This can be exploited by utilizing many resources at the same time. Creating parallel algorithms computed with FPGAs in pure HDL is difficult and time consuming. Implementation time can be greatly reduced with High-Level Synthesis compiler. This article describes design methodologies and tools, implementation and first results of created VHDL backend for RPython compiler.

  4. Low level exposure to chemicals and immune system

    SciTech Connect

    Colosio, C. . E-mail: claudio.colosio@icps.it; Birindelli, S.; Corsini, E.; Galli, C.L.; Maroni, M.

    2005-09-01

    Industrialized countries are facing an increase of diseases attributable to an alteration of the immune system function, and concern is growing that this trend could be at least partially attributable to new and modified patterns of exposure to chemicals. Among chemicals matter of concern, pesticides can be included. The Authors have reviewed the existing evidence of pesticide immunotoxicity in humans, showing that existing data are inadequate to raise conclusions on the immunotoxic risk related to these compounds. The limits of existing studies are: poor knowledge on exposure levels, heterogeneity of the approach, and difficulty in giving a prognostic significance to the slight changes often observed. To overcome these limits, the Authors have proposed a tier approach, based on three steps: the first, addressed at pointing out a possible immunomodulation; the second, at refining the results and the third one, when needed, to finalize the study and to point out concordance with previous results. Studies should preferably be carried out through comparison of pre- and post-exposure findings in the same groups of subjects to be examined immediately after the end of the exposure. A simplification of the first step approach can be used by the occupational health physician and the occupational toxicologist. Conclusions on the prognostic significance of the slight changes often observed will be reached only by validating the hypothesis generated by field studies with an epidemiological approach. In this field, the most useful option is represented by longitudinal perspective studies.

  5. The effect of sunlight exposure on interleukin-6 levels in depressive and non-depressive subjects.

    PubMed

    Levandovski, Rosa; Pfaffenseller, Bianca; Carissimi, Alicia; Gama, Clarissa S; Hidalgo, Maria Paz Loayza

    2013-03-05

    The objective of this epidemiological study was to evaluate the effect of length of sunlight exposure on interleukin 6 (IL-6) levels in depressive and non-depressive subjects. This was a cross-sectional study with 154 subjects (54 males, mean age: 43.5 ± 12.8 years) who were living in a rural area in south Brazil. Chronobiological and light parameters were assessed using the Munich Chronotype Questionnaire. Sleep quality was evaluated using the Pittsburgh Sleep Quality Index. Depressive symptoms were assessed with the Beck Depression Inventory. Plasma levels of inflammatory cytokines (IL-2, IL-4, IL-6, IL-10, tumor necrosis factor-α, and interferon) were collected during the daytime and measured. IL-6 levels showed a positive correlation with light exposure (r = 0.257; p < 0.001) and a negative correlation with the mid-sleep phase on work-free days (r = -0.177; p = 0.028). Multiple linear regression analysis showed that only the length of light exposure was an independent factor for predicting IL-6 levels (ß = 0.26; p = 0.002). In non-depressed subjects, exposure to a different intensity of light did not affect IL-6 levels (t = -1.6; p = 0.1). However, when the two depressive groups with low and high light exposure were compared, the low light exposure group had lower levels of IL-6 compared with the high light exposure group (t = -2.19 and p = 0.0037). The amount of time that participants are exposed to sunlight is directly related to their IL-6 levels. Additionally, depressed subjects differ in their IL-6 levels if they are exposed to light for differing amounts of time.

  6. The effect of sunlight exposure on interleukin-6 levels in depressive and non-depressive subjects

    PubMed Central

    2013-01-01

    Background The objective of this epidemiological study was to evaluate the effect of length of sunlight exposure on interleukin 6 (IL-6) levels in depressive and non-depressive subjects. Methods This was a cross-sectional study with 154 subjects (54 males, mean age: 43.5 ± 12.8 years) who were living in a rural area in south Brazil. Chronobiological and light parameters were assessed using the Munich Chronotype Questionnaire. Sleep quality was evaluated using the Pittsburgh Sleep Quality Index. Depressive symptoms were assessed with the Beck Depression Inventory. Plasma levels of inflammatory cytokines (IL-2, IL-4, IL-6, IL-10, tumor necrosis factor-α, and interferon) were collected during the daytime and measured. Results IL-6 levels showed a positive correlation with light exposure (r = 0.257; p < 0.001) and a negative correlation with the mid-sleep phase on work-free days (r = -0.177; p = 0.028). Multiple linear regression analysis showed that only the length of light exposure was an independent factor for predicting IL-6 levels (ß = 0.26; p = 0.002). In non-depressed subjects, exposure to a different intensity of light did not affect IL-6 levels (t = -1.6; p = 0.1). However, when the two depressive groups with low and high light exposure were compared, the low light exposure group had lower levels of IL-6 compared with the high light exposure group (t = -2.19 and p = 0.0037). Conclusions The amount of time that participants are exposed to sunlight is directly related to their IL-6 levels. Additionally, depressed subjects differ in their IL-6 levels if they are exposed to light for differing amounts of time. PMID:23497121

  7. High Throughput Exposure Estimation Using NHANES Data (SOT)

    EPA Science Inventory

    In the ExpoCast project, high throughput (HT) exposure models enable rapid screening of large numbers of chemicals for exposure potential. Evaluation of these models requires empirical exposure data and due to the paucity of human metabolism/exposure data such evaluations includ...

  8. High Throughput Exposure Estimation Using NHANES Data (SOT)

    EPA Science Inventory

    In the ExpoCast project, high throughput (HT) exposure models enable rapid screening of large numbers of chemicals for exposure potential. Evaluation of these models requires empirical exposure data and due to the paucity of human metabolism/exposure data such evaluations includ...

  9. Ortho-phthalaldehyde exposure levels among endoscope disinfection workers.

    PubMed

    Miyajima, Keiko; Yoshida, Jin; Kumagai, Shinji

    2010-01-01

    Recently, the use of ortho-phthalaldehyde (OPA) has been increasing as an alternative to glutaraldehyde for endoscope disinfection. To better understand OPA exposure and its health effects among disinfection workers, we conducted environmental monitoring and administered a questionnaire in 17 endoscope disinfection rooms. There were 9 manual disinfection rooms using immersion vats for scope disinfection and 8 automatic rooms using automatic washers. OPA exposure concentration during the disinfection process of scope was significantly higher in the manual group (median: 1.43ppb, range: not detected (ND-5.37ppb) than in the automatic group (median: 0.35 ppb, range: ND-0.69 ppb). Similarly, during charging and discharging the antiseptic solution, OPA levels were significantly higher in the manual group (median: 2.58 ppb, range: 0.92-10.0 ppb) than in the automatic group (median: 0.46ppb, range: ND-1.35 ppb). Time-weighted averages of OPA exposure concentration during work shifts were 0.33 to 1.15 ppb (median 0.66 ppb) in the manual group and 0.13 to 1.28 ppb (median 0.33 ppb) in the automatic group, which suggests that manual workers are exposed to OPA at higher levels. Among 80 female disinfection workers who used only antiseptic solutions containing OPA, the incidence of disinfection-related complaints were 10% skin, 9% eye, and 16% respiratory symptoms. These findings suggest that it is desirable to introduce automatic washers to decrease OPA exposure levels among disinfection workers.

  10. Glutathione level after long-term occupational elemental mercury exposure

    SciTech Connect

    Kobal, Alfred Bogomir Prezelj, Marija; Horvat, Milena; Krsnik, Mladen; Gibicar, Darija; Osredkar, Josko

    2008-05-15

    Many in vitro and in vivo studies have elucidated the interaction of inorganic mercury (Hg) and glutathione. However, human studies are limited. In this study, we investigated the potential effects of remote long-term intermittent occupational elemental Hg vapour (Hg{sup o}) exposure on erythrocyte glutathione levels and some antioxidative enzyme activities in ex-mercury miners in the period after exposure. The study included 49 ex-mercury miners divided into subgroups of 28 still active, Hg{sup o}-not-exposed miners and 21 elderly retired miners, and 41 controls, age-matched to the miners subgroup. The control workers were taken from 'mercury-free works'. Reduced glutathione (GSH) and oxidized disulphide glutathione (GSSG) concentrations in haemolysed erythrocytes were determined by capillary electrophoresis, while total glutathione (total GSH) and the GSH/GSSG ratio were calculated from the determined values. Catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR) activities in erythrocytes were measured using commercially available reagent kits, while urine Hg (U-Hg) concentrations were determined by cold vapour atomic absorption (CVAAS). No correlation of present U-Hg levels, GSH, GSSG, and antioxidative enzymes with remote occupational biological exposure indices were found. The mean CAT activity in miners and retired miners was significantly higher (p<0.05) than in the controls. No differences in mean GPx activity among the three groups were found, whereas the mean GR activity was significantly higher (p<0.05) in miners than in retired miners. The mean concentrations of GSH (mmol/g Hb) in miners (13.03{+-}3.71) were significantly higher (p<0.05) than in the control group (11.68{+-}2.66). No differences in mean total GSH, GSSG levels, and GSH/GSSG ratio between miners and controls were found. A positive correlation between GSSG and present U-Hg excretion (r=0.41, p=0.001) in the whole group of ex-mercury miners was observed. The

  11. Elevated blood lead levels from exposure via a radiator workshop.

    PubMed

    Treble, R G; Thompson, T S; Morton, D N

    1998-04-01

    Elevated lead levels were discovered in blood samples collected from family members where both the father and the mother worked in a radiator repair workshop. The father and mother were found to have blood lead levels of 2.0 and 0.5 mumol/L (41.7 and 10.4 micrograms/dL), respectively. The father's blood lead level was just below the Canadian occupational health and safety intervention level (2.5 mumol/L or 52.1 micrograms/dL). The two children had blood lead levels of 1.0 and 0.8 mumol/L (20.8 and 16.7 micrograms/dL), both of which are in excess of the recommended guideline for intervention in the case of children (0.5 mumol/L or 10.4 micrograms/dL). The exposure of the two children was possibly due to a combination of pathways including exposure at the workshop itself during visits and also the transportation of lead-containing dust to the home environment.

  12. The ALICE high level trigger

    NASA Astrophysics Data System (ADS)

    Alt, T.; Grastveit, G.; Helstrup, H.; Lindenstruth, V.; Loizides, C.; Röhrich, D.; Skaali, B.; Steinbeck, T.; Stock, R.; Tilsner, H.; Ullaland, K.; Vestbø, A.; Vik, T.; Wiebalck, A.; the ALICE Collaboration

    2004-08-01

    The ALICE experiment at LHC will implement a high-level trigger system for online event selection and/or data compression. The largest computing challenge is posed by the TPC detector, which requires real-time pattern recognition. The system entails a very large processing farm that is designed for an anticipated input data stream of 25 GB s-1. In this paper, we present the architecture of the system and the current state of the tracking methods and data compression applications.

  13. High-Level Connectionist Models

    DTIC Science & Technology

    1993-10-01

    Artficial Intelligence Research Computer and Information Science Department The Ohio State Universiy Columbus, Ohio 43210 pja@ci.ohio-state.edu saunders...Peter J. Angeline, Gregory M. Saunders and Jordan B. Pollack Laboratory for Artficial Intelligence Research Computer and 1i4ormadon Science Deparment...AD-A273 638 OHIOi High-Level Connectionist Models 5LPJE UNIVERSITY Jordan B. Pollack Laboratory for Artificial Intelligence Research Department of

  14. Modification of otoacoustic emissions following ear-level exposure to MP3 player music.

    PubMed

    Bhagat, Shaum P; Davis, Anne M

    2008-12-01

    The purpose of this study was to examine if a pre-determined exposure level and duration of MP3 player music would result in significant changes in cochlear function when measured with audiometric and physiological methods. Distortion-product otoacoustic emissions (DPOAEs), synchronized spontaneous otoacoustic emissions (SSOAEs), and hearing thresholds were measured in 20 normal-hearing adults before and after a 30-minute MP3 player music exposure. DPOAEs were acquired with 65/45 dB SPL primary tones (f(2)=0.842-7.996 kHz) with a frequency resolution of 8 points/octave. A probe microphone system recorded ear-canal music levels and was used to equalize levels at approximately 85 dBC across individuals during the music presentation. Comparison of pre- and post-exposure measurements revealed no significant differences in hearing thresholds, but DPOAE levels in half-octave bands centered from 1.4-6.0 kHz were significantly reduced following the music exposure. Post-exposure shifts in SSOAE frequency and level were highly variable in individuals identified with SSOAEs. The results for the exposure conditions explored in this study indicate that changes in otoacoustic emissions may precede the development of music-induced hearing threshold shifts.

  15. Acute myeloid and chronic lymphoid leukaemias and exposure to low-level benzene among petroleum workers

    PubMed Central

    Rushton, L; Schnatter, A R; Tang, G; Glass, D C

    2014-01-01

    Background: High benzene exposure causes acute myeloid leukaemia (AML). Three petroleum case–control studies identified 60 cases (241 matched controls) for AML and 80 cases (345 matched controls) for chronic lymphoid leukaemia (CLL). Methods: Cases were classified and scored regarding uncertainty by two haematologists using available diagnostic information. Blinded quantitative benzene exposure assessment used work histories and exposure measurements adjusted for era-specific circumstances. Statistical analyses included conditional logistic regression and penalised smoothing splines. Results: Benzene exposures were much lower than previous studies. Categorical analyses showed increased ORs for AML with several exposure metrics, although patterns were unclear; neither continuous exposure metrics nor spline analyses gave increased risks. ORs were highest in terminal workers, particularly for Tanker Drivers. No relationship was found between benzene exposure and risk of CLL, although the Australian study showed increased risks in refinery workers. Conclusion: Overall, this study does not persuasively demonstrate a risk between benzene and AML. A previously reported strong relationship between myelodysplastic syndrome (MDS) (potentially previously reported as AML) at our study's low benzene levels suggests that MDS may be the more relevant health risk for lower exposure. Higher CLL risks in refinery workers may be due to more diverse exposures than benzene alone. PMID:24357793

  16. Prenatal androgen exposure and children's aggressive behavior and activity level.

    PubMed

    Spencer, Debra; Pasterski, Vickie; Neufeld, Sharon; Glover, Vivette; O'Connor, Thomas G; Hindmarsh, Peter C; Hughes, Ieuan A; Acerini, Carlo L; Hines, Melissa

    2017-09-19

    Some human behaviors, including aggression and activity level, differ on average for males and females. Here we report findings from two studies investigating possible relations between prenatal androgen and children's aggression and activity level. For study 1, aggression and activity level scores for 43 girls and 38 boys, aged 4 to 11years, with congenital adrenal hyperplasia (CAH, a genetic condition causing increased adrenal androgen production beginning prenatally) were compared to those of similarly-aged, unaffected relatives (41 girls, 31 boys). Girls with CAH scored higher on aggression than unaffected girls, d=0.69, and unaffected boys scored higher on activity level than unaffected girls, d=0.50. No other group differences were significant. For study 2, the relationship of amniotic fluid testosterone to aggression and activity level was investigated in typically-developing children (48 girls, 44 boys), aged 3 to 5years. Boys scored higher than girls on aggression, d=0.41, and activity level, d=0.50. However, amniotic fluid testosterone was not a significant predictor of aggression or activity level for either sex. The results of the two studies provide some support for an influence of prenatal androgen exposure on children's aggressive behavior, but not activity level. The within-sex variation in amniotic fluid testosterone may not be sufficient to allow reliable assessment of relations to aggression or activity level. Copyright © 2017. Published by Elsevier Inc.

  17. Low level methylmercury exposure affects neuropsychological function in adults

    PubMed Central

    Yokoo, Edna M; Valente, Joaquim G; Grattan, Lynn; Schmidt, Sérgio Luís; Platt, Illeane; Silbergeld, Ellen K

    2003-01-01

    Background The neurotoxic effects of methylmercury (MeHg) have been demonstrated in both human and animal studies. Both adult and fetal brains are susceptible to the effects of MeHg toxicity. However, the specific effects of adult exposures have been less well-documented than those of children with prenatal exposures. This is largely because few studies of MeHg exposures in adults have used sensitive neurological endpoints. The present study reports on the results of neuropsychological testing and hair mercury concentrations in adults (>17 yrs) living in fishing communities of Baixada Cuiabana (Mato Grosso) in the Pantanal region of Brazil. Methods A cross-sectional study was conducted in six villages on the Cuiaba River. Participants included 129 men and women older than 17 years of age. They were randomly selected in proportion to the age range and number of inhabitants in each village. Questionnaire information was collected on demographic variables, including education, occupation, and residence history. Mercury exposure was determined by analysis of hair using flameless atomic absorption spectrophotometry. The neurocognitive screening battery included tests from the Wechsler Memory Scale and the Wechsler Adult Intelligence Scale, Concentrated Attention Test of the Toulouse-Pierron Factorial Battery, the Manual Ability Subtests of the Tests of Mechanical Ability, and the Profile of Mood States. Results Mercury exposures in this population were associated with fish consumption. The hair mercury concentration in the 129 subjects ranged from 0.56 to 13.6 μg/g; the mean concentration was 4.2 ± 2.4 micrograms/g and the median was 3.7 μg/g. Hair mercury levels were associated with detectable alterations in performance on tests of fine motor speed and dexterity, and concentration. Some aspects of verbal learning and memory were also disrupted by mercury exposure. The magnitude of the effects increased with hair mercury concentration, consistent with a dose

  18. Physiological responses during exposure to carbon dioxide and bioeffluents at levels typically occurring indoors.

    PubMed

    Zhang, X; Wargocki, P; Lian, Z

    2017-01-01

    Twenty-five subjects were exposed to different levels of carbon dioxide (CO2 ) and bioeffluents. The ventilation rate was set high enough to create a reference condition of 500 ppm CO2 with subjects present; additional CO2 was then added to supply air to reach levels of 1000 or 3000 ppm, or the ventilation rate was reduced to allow metabolically generated CO2 to reach the same two levels (bioeffluents increased as well). Heart rate, blood pressure, end-tidal CO2 (ETCO2 ), oxygen saturation of blood (SPO2 ), respiration rate, nasal peak flow, and forced expiration were monitored, and the levels of salivary α-amylase and cortisol were analyzed. The subjects performed a number of mental tasks during exposures and assessed their levels of comfort and the intensity of their acute health symptoms. During exposure to CO2 at 3000 ppm, when CO2 was added or ventilation was restricted, ETCO2 increased more and heart rate decreased less than the changes that occurred in the reference condition. Exposure to bioeffluents, when metabolically generated CO2 was at 3000 ppm, significantly increased diastolic blood pressure and salivary α-amylase level compared with pre-exposure levels, and reduced the performance of a cue-utilization test: These effects may suggest higher arousal/stress. A model is proposed describing how mental performance is affected by exposure to bioeffluents. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  19. [Myocardial ultrastructural changes in rats following different levels of acute +Gz exposure].

    PubMed

    Zheng, Jun; Liu, Cheng-gang; Ren, Li; Xiao, Xiao-guang; Xu, Shu-xuan; Wang, Ping; Ji, Gui-ying

    2004-06-01

    To observe the effects of different levels of acute +Gz exposure on myocardial ultrastructure of rats and provide experimental basis for further development of anti-G measures. Twenty male Wistar rats were randomly divided into 4 groups (n=5): normal control group, +20 Gz group, +10 Gz group and +5 Gz group. Profile of the centrifuge +Gz exposure was trapezoidal, in which +20 Gz lasted for 30 s, +10 Gz for 1.5 min. +5 Gz exposure was repeated for 3 times with 30 min interval and each for 1.5 min. Myocardial tissue of left ventricle was sampled for transmission electron microscopy 5 h after exposure. +20 Gz and +10 Gz exposure caused obvious edema of myocardial and endothelial cells, myofibril disorder and injuries of mitochondria and nucleus. Breaks of myocardial fiber, formation of contraction bands and rupture of mitochondria were also observed in +20 Gz group. In +5 Gz group, there was still slight edema of myocardial and endothelial cells, while organic changes of myocardial ultrastructure were not observed. High +Gz exposure can cause myocardial ultrastructural injury in rats. Slight reversible injured response can also be observed in myocardial cell after repeated moderate level of +Gz exposure. This indicates that attention should be paid to the study of the effect of high +Gz on heart in pilots.

  20. High Throughput Assays for Exposure Science (NIEHS OHAT ...

    EPA Pesticide Factsheets

    High throughput screening (HTS) data that characterize chemically induced biological activity have been generated for thousands of chemicals by the US interagency Tox21 and the US EPA ToxCast programs. In many cases there are no data available for comparing bioactivity from HTS with relevant human exposures. The EPA’s ExpoCast program is developing high-throughput approaches to generate the needed exposure estimates using existing databases and new, high-throughput measurements. The exposure pathway (i.e., the route of chemical from manufacture to human intake) significantly impacts the level of exposure. The presence, concentration, and formulation of chemicals in consumer products and articles of commerce (e.g., clothing) can therefore provide critical information for estimating risk. We have found that there are only limited data available on the chemical constituents (e.g., flame retardants, plasticizers) within most articles of commerce. Furthermore, the presence of some chemicals in otherwise well characterized products may be due to product packaging. We are analyzing sample consumer products using 2D gas chromatograph (GC) x GC Time of Flight Mass Spectrometry (GCxGCTOF/MS), which is suited for forensic investigation of chemicals in complex matrices (including toys, cleaners, and food). In parallel, we are working to create a reference library of retention times and spectral information for the entire Tox21 chemical library. In an examination of five p

  1. Low-level exposure to radiofrequency electromagnetic fields: health effects and research needs.

    PubMed

    Repacholi, M H

    1998-01-01

    The World Health Organization (WHO), the International Commission on Non-Ionizing Radiation Protection (ICNIRP), and the German and Austrian Governments jointly sponsored an international seminar in November of 1996 on the biological effects of low-level radiofrequency (RF) electromagnetic fields. For purposes of this seminar, RF fields having frequencies only in the range of about 10 MHz to 300 GHz were considered. This is one of a series of scientific review seminars held under the International Electromagnetic Field (EMF) Project to identify any health hazards from EMF exposure. The scientific literature was reviewed during the seminar and expert working groups formed to provide a status report on possible health effects from exposure to low-level RF fields and identify gaps in knowledge requiring more research to improve health risk assessments. It was concluded that, although hazards from exposure to high-level (thermal) RF fields were established, no known health hazards were associated with exposure to RF sources emitting fields too low to cause a significant temperature rise in tissue. Biological effects from low-level RF exposure were identified needing replication and further study. These included in vitro studies of cell kinetics and proliferation effects, effects on genes, signal transduction effects and alterations in membrane structure and function, and biophysical and biochemical mechanisms for RF field effects. In vivo studies should focus on the potential for cancer promotion, co-promotion and progression, as well as possible synergistic, genotoxic, immunological, and carcinogenic effects associated with chronic low-level RF exposure. Research is needed to determine whether low-level RF exposure causes DNA damage or influences central nervous system function, melatonin synthesis, permeability of the blood brain barrier (BBB), or reaction to neurotropic drugs. Reported RF-induced changes to eye structure and function should also be investigated

  2. Cataractogenesis following high-LET radiation exposure.

    PubMed

    Hamada, Nobuyuki; Sato, Tatsuhiko

    Biological effectiveness of ionizing radiation differs with its linear energy transfer (LET) such that high-LET radiation is more effective for various biological endpoints than low-LET radiation. Human exposure to high-LET radiation occurs in cancer patients, nuclear workers, aviators, astronauts and other space travellers. From the radiation protection viewpoint, the ocular lens is among the most radiosensitive tissues in the body, and cataract (a clouding of the normally transparent lens) is classified as tissue reactions (formerly called nonstochastic or deterministic effects) with a threshold below which no effect would occur. To prevent radiation cataracts, the International Commission on Radiological Protection (ICRP) has recommended an equivalent dose limit for the lens according to the threshold for vision-impairing cataracts. ICRP recommended the threshold of >8Gy in 1984 and an occupational dose limit of 150mSv/year in 1980. These remained unchanged until 2011, when ICRP recommended lowering the threshold to 0.5Gy and the dose limit to 20mSv/year (averaged over 5 years with no single year exceeding 50mSv). Although such reduction of the threshold was based on findings from low-LET radiation, the dose limit was recommended in Sv. Historically, the lens is the exceptional tissue for which ICRP had assigned a special factor in addition to a general radiation weighting factor, predicated on a belief that the lens is more vulnerable to high-LET radiation than other tissues. Considering such radiosensitive nature of the lens, a deeper understanding of a cataractogenic potential of high-LET radiation is indispensable. This review is thus designed to provide an update on the current knowledge as to high-LET radiation cataractogenesis. To this end, changes in ICRP recommendations on lenticular radiation protection, epidemiological and biological findings on high-LET cataractogenesis are reviewed, and future research needs are then discussed.

  3. Exposures influencing total IgA level in colostrum.

    PubMed

    Munblit, D; Sheth, S; Abrol, P; Treneva, M; Peroni, D G; Chow, L-Y; Boner, A L; Pampura, A; Warner, J O; Boyle, R J

    2016-02-01

    Immunoglobulin A (IgA) is a predominant immunoglobulin present in human breast milk and is known to play an important role in infant gut immunity maturation. Breast milk composition varies between populations, but the environmental and maternal factors responsible for these variations are still unclear. We examined the relationship between different exposures and levels of IgA in colostrum. The objective of this study was to examine whether exposures analysed influence levels of IgA in colostrum. The present study used 294 colostrum samples from the MecMilk International cohort, collected from women residing in London, Moscow and Verona. Samples were analysed in automated Abbott Architect Analyser. We found an inverse correlation between time postpartum and colostrum total IgA level (r=-0.49, P<0.001). Adjusting for maternal parity, smoking, fresh fruit and fish consumption and allergen sensitization, multiple regression model showed that IgA levels were influenced by colostrum collection time (P<0.0001) and country of collection (P<0.01). Mode of delivery influence did not appear to be significant in univariate comparisons, once adjusted for the above maternal characteristics it showed a significant influence on total IgA (P=0.01). We conclude that the concentration of IgA in colostrum drops rapidly after birth and future studies should always consider this factor in analysis. IgA concentration varied significantly between countries, with the highest level detected in Moscow and lowest in Verona. Mode of delivery effect should be confirmed on larger cohorts. Further work is needed to determine ways to correct for IgA decline over time in colostrum, and to find the cause of variations in IgA levels between the countries.

  4. Assessment of road users' elemental carbon personal exposure levels, London, UK

    NASA Astrophysics Data System (ADS)

    Adams, H. S.; Nieuwenhuijsen, M. J.; Colvile, R. N.; Older, M. J.; Kendall, M.

    Little is known about particulate elemental carbon (EC) personal exposure levels, a key component of diesel exhaust, specifically in transport microenvironments. A method utilizing the optical properties of EC particles has been applied to personal exposure measurement filter samples. In a series of field studies carried out in London, UK, during 1999-2000 over 400 fine particle (PM 2.5) personal exposure level measurements were taken for journeys in bicycle, bus, car and underground rail transport microenvironments, along three main fixed routes. The particulate EC contribution to the PM 2.5 personal exposure was assessed indirectly by means of an optical technique and with the development and use of a size fraction specific and site-specific calibration curve. In this first EC personal exposure study of transport users geometric mean exposure levels in the summer field campaign were 11.2 μg m -3 (GSD=2.7) for cyclists, 13.6 μg m -3 (GSD=1.9) for bus passengers and 21.6 μg m -3 (GSD=2.1) for car drivers; corresponding exposure levels in the winter were 16.4 μg m -3 (GSD=1.8), 18.6 μg m -3 (GSD=2.3) and 27.3 μg m -3 (GSD=2.0), respectively. EC/PM 2.5 ratios were approximately 0.5-0.6 for bicycle and bus modes and 0.7-0.8 for the car mode. EC/PM 2.5 ratios for different routes ranged from approximately 0.7 for Route 1 to 0.4 for Route 3. Cyclists had the lowest exposure to EC, and car occupants the highest exposure. A large difference in exposure levels between a central high traffic density route and the other less central routes was observed. Particulate EC was a very significant proportion of the total PM 2.5 personal exposure and EC personal exposure levels were considerably higher than reported fixed site monitor EC concentrations.

  5. [Levels of phthalate internal exposure levels in pregnant women and influencing factors].

    PubMed

    Yang, Yue; Shi, Mingming; Chen, Biqin; Lin, Jianfeng; Yang, Songjing; Zhu, Baoping; Zhuang, Baoling; Jia, Yuzhu; Huang, Zhenxiang; Chen, Jing; Liu, Huifen; Chen, Jianghui; Su, Yanhua; Ke, Xiayi; Zhao, Benhua

    2015-11-01

    To investigate the levels and influencing factors of phthalate internal exposure in pregnant women (gestation age ≤ 16 weeks). During April to June in 2013, 1 020 pregnant women (gestation age ≤ 16 weeks) who had established the maternal care manual were recruited in maternal and child health hospital of Siming District, Xiamen city. Participators were asked to complete a questionnaire to obtain information on socio-demographic characteristics, lifestyle behaviors, and antenatal examination and to provide a urine sample. Finally, 998 pregnant women who provided a urine sample and completed the questionnaire were enrolled. Adopting systematic sampling method, 100 ones were selected randomly among 998 pregnant women. High performance liquid chromatography-electrospray ionization-tandern mass was used to determine the concentration of five phthalate monoesters in each urine, including mono-n-methyl phthalate (MMP), mono-ethyl phthalate (MEP), mono-butyl phthalate (MBP), mono-benzyl phthalate (MBzP), mono-ethylhexyl phthalate (MEHP). Based on the measurements and questionnaire data, multivariate logistic regression was used to analyze the association between the phthalate monoester levels and potential influential factors. The detection rates of MMP, MEP, MBP, MBzP and MEHP in 100 pregnant urine samples were 94%, 93%, 87%, 83%, 99%, respectively. And the urinary median uncorrected concentrations of MMP, MEP, MBP, MBzP and MEHP in 100 urine samples were 20.56, 17.62, 10.15, 2.03, and 5.12 ng/ml, respectively. Specific gravity-corrected concentration were 20.81, 20.36, 12.88, 2.58, 5.00 ng/ml, respectively. The results of multivariate logistic regression analysis indicated that: education degree was negatively associated with urinary concentration of MMP, MEP, MBP, MBzP and MEHP, OR (95% CI) were 0.495 (0.253-0.966), 0.380 (0.191-0.755), 0.379 (0.186-0.774), 0.401 (0.196-0.819), 0.373(0.183-0.762), respectively. Participants who had hair permed and dyed during

  6. Personal UV exposure in high albedo alpine sites

    NASA Astrophysics Data System (ADS)

    Siani, A. M.; Casale, G. R.; Diémoz, H.; Agnesod, G.; Kimlin, M. G.; Lang, C. A.; Colosimo, A.

    2008-07-01

    Mountain sites experience enhanced UV radiation levels due to the concurrent effects of shorter radiation path-length, low aerosol load and high reflectivity of the snow surfaces. This study was encouraged by the possibility to collect original data of personal dose on a specific anatomical site (erythemally effective UV dose on the forehead) of two groups of volunteers (ski instructors and skiers) in the mountainous areas of Italy (the Alpine site of La Thuile-Les Suches in Valle d'Aosta region). Personal doses were assessed using polysulphone dosimetry. Exposure Ratio (ER), defined as the ratio between the personal dose and the corresponding ambient dose (i.e. erythemally weighted dose received by a horizontal surface) during the same exposure period was taken into account. In addition measuring skin colours as biological markers of individual response to UV exposure, was also carried out on the forearm and cheek of each volunteer before and after exposure. The median ER, taking into account the whole sample, is 0.60 in winter, with a range of 0.29 to 1.46, and 1.02 in spring, ranging from 0.46 to 1.72. No differences in ERs were found between skiers and instructors in spring while in winter skiers experienced lower values. Regarding skin colorimetric parameters the main result was that both skiers and instructors had on average significantly lower values of luminance after exposure i.e.~they became darker. It was found that the use of sunscreen and individual skin photo-type did not produce significant variations in ER across instructor/skier group by day and by seasons (p>0.05). It seems that sunscreen use only at the beginning of the exposure or in a few cases a couple of times during exposure (at difference with the specific instructions sheets), was not sufficient to change significantly skin colorimetric parameters across participants. In conclusion UV personal doses on the ski-fields are often significantly higher than those on horizontal surfaces and

  7. High lead exposure in two leaded bronze ingot foundry workers.

    PubMed

    Song, Yoojun; Suh, Chunhui; Kim, Shin-Ae; Kim, Nami; Kim, Sung-Min; Jeong, Seong-Wook; Kim, Se-Yeong; Kim, Kun-Hyung; Kim, Jeong-Ho; Son, Byung-Chul; Lee, Chae-Kwan; Lee, Jong-Tae

    2014-01-01

    Awareness about lead poisoning in South Korea has increased; however, occupational exposures occurring in small-scale businesses have not been thoroughly investigated. We report two cases of high lead exposure in a leaded bronze ingot foundry. Two employees, a 54-year-old primary operator and a 46-year-old assistant, at a small-scale metalworking company who had been employed for 18 years and 1 month, respectively, showed elevated blood lead levels (61.1 μg/dL and 51.7 μg/dL, respectively) at an occupational health checkup. Neither worker complained of abnormal symptoms nor signs related to lead poisoning. Health assessment follow-ups were conducted and biological exposure indices of lead were calculated every four weeks. After the initial follow-up assessment, both workers were relocated from the foundry process to the metalworking process. In addition, a localized exhaust system was installed after the second follow-up. Foundry workers in a small-scale businesses might be at high risk of lead exposure because these businesses might be vulnerable to poor industrial hygiene. Therefore, regular occupational health checkups are required.

  8. Evaluating Rapid Models for High-Throughput Exposure Forecasting (SOT)

    EPA Science Inventory

    High throughput exposure screening models can provide quantitative predictions for thousands of chemicals; however these predictions must be systematically evaluated for predictive ability. Without the capability to make quantitative, albeit uncertain, forecasts of exposure, the ...

  9. Evaluating Rapid Models for High-Throughput Exposure Forecasting (SOT)

    EPA Science Inventory

    High throughput exposure screening models can provide quantitative predictions for thousands of chemicals; however these predictions must be systematically evaluated for predictive ability. Without the capability to make quantitative, albeit uncertain, forecasts of exposure, the ...

  10. [Levels of dichlorodiphenyltrichloroethane internal exposure levels in pregnant women of Xiamen and influencing factors].

    PubMed

    Yu, X S; He, J; Chen, J H; Lai, Z B; Su, Y H; Shi, M M; Huang, Z X; Cheng, Q J; Ke, X Y; Zhao, B H

    2016-11-06

    Objective: To investigate the level of and factors influencing internal exposure to dichlorodiphenyltrichloroethane (DDT) in pregnant women. Methods: In all, 1 064 pregnant women were recruited in a hospital of Xiamen. Participants were asked to complete a questionnaire to obtain data on sociodemographic characteristics and lifestyle. Peripheral venous blood and cord blood samples were collected. Of the 1 064 pregnant women, 600 were enrolled in this study after completing the questionnaire and providing peripheral venous blood and cord blood. Among those women, 150 were selected randomly using a systematic sampling method. A gas chromatography coupled electron capture detector was used to determine the concentration of six DDT homologues: p,p'-dichlorodiphenyltrichloroethane (p,p'-DDT), o,p'-dichlorodiphenyltrichloroethane (o,p'-DDT), p,p'-dichlorodiphenyldichloroethane (p,p'-DDD), o,p'-dichlorodiphenyldichloroethane (o,p'-DDD), p,p'-dichlorodiphenylethylene (p,p'-DDE), and o,p'-dichlorodiphenylethylene (o,p'-DDE) . Pregnant women were divided into two groups according to DDT concentration: a low concentration group (detection value≤P50) and a high concentration group (detection value>P50). multivariate logistic regression was used to analyze the association between the DDT levels and potential influencing factors which investigated in the questionnaire. Results: The detection rates of p,p'-DDT, o,p'-DDT, p,p'-DDD, o,p'-DDD, p,p'-DDE and o,p'-DDE in the peripheral venous blood samples from the 150 pregnant women were 83.3% (125), 29.3% (44), 58.0% (87), 24.0% (36), 82.0% (123), and 34.7% (52), respectively. The median concentrations were 1.56, 0.03, 0.07, 0.03, 0.93 and 0.03 μg/ml, respectively. The detection rates of p,p'-DDT, o,p'-DDT, p,p'-DDD, o,p'-DDD, p,p'-DDE and o,p'-DDE in the cord blood samples were 69.3% (104), 10.7% (16), 29.3% (44), 20.7% (31), 81.3% (122) and 45.3% (68), and the median concentrations were 0.41, 0.03, 0.03, 0.03, 0.42 and 0.03

  11. [Formaldehyde exposure levels and exposure control measures during an anatomy dissecting course].

    PubMed

    Tanaka, Kazuko; Nishiyama, Keiji; Yaginuma, Hiroyuki; Sasaki, Akihiko; Maeda, Takahumi; Kaneko, Sin-ya; Onami, Tetsuo; Tanaka, Masatoshi

    2003-06-01

    The evaporation of formaldehyde from cadavers can produce high exposures among students and instructors. A possible causal role for formaldehyde has been considered likely for tumor of the nasopharynx and the nasal cavities in human beings. Due to this reason, Japan Ministry of Education, Culture, Sports, Science and Technology (MEXT) has set a guideline, which includes--decrease in gaseous formaldehyde in gross anatomy dissection laboratories and a guide to medical students about the toxicity of formaldehyde and protective method to avoid damages to skin, mucous, membrane, etc, in 2002. To understand what effective plans should be regarding the awareness of students about this notification, this study measured the gaseous formaldehyde concentrations in the anatomy dissection room and also analyzed the formaldehyde-related symptoms, and frequency of using protective measures. The study was conducted over a period of 3 months during the anatomy dissection exercise. We found that immediately after removing the cadavers' plastic covering, formaldehyde concentrations in the dissection room increased sharply. The concentration reached a peak point of 0.62 ppm after 10 minutes of starting of the class. This was much above the recommended level of 0.5 ppm set by Japan Society for Occupational Health. After 30 minutes of achieving the peak the formaldehyde level started decreasing gradually to a level of 0.11 ppm. Formaldehyde-related symptoms were observed in 59% of students. They had experienced symptoms of irritation of eyes, nose, throat, airways, skin, and headache during the course. Ocular discomfort was found significantly higher in the contact lenses users compared to the spectacle users or the normal eye sight group. Although, the guidelines about toxicity of formaldehyde and its protective measures to prevent damages to skin, mucous membrane etc. were informed to every student, only 52% of the students used both the mask containing activated carbon and the rubber

  12. Does apartment's distance to an in-built transformer room predict magnetic field exposure levels?

    PubMed

    Huss, Anke; Goris, Kelly; Vermeulen, Roel; Kromhout, Hans

    2013-01-01

    It has been shown that magnetic field exposure in apartments located directly on top or adjacent to transformer rooms is higher compared with exposure in apartments located further away from the transformer rooms. It is unclear whether this also translates into exposure contrast among individuals living in these apartments. We performed spot measurements of magnetic fields in 35 apartments in 14 apartment buildings with an in-built transformer and additionally performed 24-h personal measurements in a subsample of 24 individuals. Apartments placed directly on top of or adjacent to a transformer room had on average exposures of 0.42 μT, apartments on the second floor on top of a transformer room, or sharing a corner or edge with the transformer room had 0.11 μT, and apartments located further away from the transformer room had levels of 0.06 μT. Personal exposure levels were approximately a factor 2 lower compared with apartment averages, but still showed exposure contrasts, but only for those individuals who live in the apartments directly on top or adjacent to a transformer room compared with those living further away, with 0.23 versus 0.06 μT for personal exposure when indoors, respectively. A classification of individuals into 'high' and 'low' exposed based on the location of their apartment within a building with an in-built transformer is possible and could be applied in future epidemiological studies.

  13. Reproductive toxicity of low-level lead exposure in men

    SciTech Connect

    Telisman, Spomenka Colak, Bozo; Pizent, Alica; Jurasovic, Jasna; Cvitkovic, Petar

    2007-10-15

    Parameters of semen quality, seminal plasma indicators of secretory function of the prostate and seminal vesicles, sex hormones in serum, and biomarkers of lead, cadmium, copper, zinc, and selenium body burden were measured in 240 Croatian men 19-52 years of age. The subjects had no occupational exposure to metals and no known other reasons suspected of influencing male reproductive function or metal metabolism. After adjusting for age, smoking, alcohol, blood cadmium, and serum copper, zinc, and selenium by multiple regression, significant (P<0.05) associations of blood lead (BPb), {delta}-aminolevulinic acid dehydratase (ALAD), and/or erythrocyte protoporphyrin (EP) with reproductive parameters indicated a lead-related increase in immature sperm concentration, in percentages of pathologic sperm, wide sperm, round sperm, and short sperm, in serum levels of testosterone and estradiol, and a decrease in seminal plasma zinc and in serum prolactin. These reproductive effects were observed at low-level lead exposure (BPb median 49 {mu}g/L, range 11-149 {mu}g/L in the 240 subjects) common for general populations worldwide. The observed significant synergistic effect of BPb and blood cadmium on increasing serum testosterone, and additive effect of a decrease in serum selenium on increasing serum testosterone, may have implications on the initiation and development of prostate cancer because testosterone augments the progress of prostate cancer in its early stages.

  14. ELF (extremely-low-frequency): Exposure levels, bioeffects and epidemiology

    SciTech Connect

    Anderson, L.E.

    1990-06-01

    Extremely-low-frequency (ELF) electromagnetic fields arise from a variety of sources including power distribution networks, public transportation systems, electrical appliances and motors, electrically heated beds and blankets, etc. In fact, in an industrialized society, people and animals are bathed in complex milieu of elevated electromagnetic fields. The ways in which exposure to these ELF electric and magnetic fields may affect biological systems are not obvious. Ionizing radiation can interact with neutral molecules to form chemically reactive radical or ionic species; however, ELF radiation transfers energy to tissues at a level lower than is already present in the form of thermal energy. ELF electromagnetic fields, nonetheless, appear to interact with tissue, and in particular with neural tissue in some whole-animal and cellular systems. This paper evaluates possible interactions between the contemporary electromagnetic environment and living organisms, and whether such influences are temporary or long lasting, beneficial or harmful. In studies on electric and magnetic fields, a broad range of exposure levels has been employed from a few volts/meter to more than 100 kV/m, and from 0.01 to 30 millitessla. A equally wide span of biological endpoints have been evaluated for possible response to ELF fields. 26 refs., 1 fig., 1 tab.

  15. A study of the hematologic effects of chronic low-level exposure to benzene

    SciTech Connect

    Collins, J.J.; Conner, P.; Friedlander, B.R.; Easterday, P.A.; Nair, R.S.; Braun, J. )

    1991-05-01

    A study of 200 persons working with benzene showed no differences in commonly measured hematologic outcomes when compared with 268 nonbenzene workers in the same plant. Exposures ranged from 0.01 ppm to a high of 1.40 ppm 8-hour time weighted average over a 10-year period. Several other factors (age, sex, race, and smoking), however, were associated with these outcomes, indicating the importance of considering confounding factors when comparing hematology results. Exposure to low levels of benzene does not appear to produce an increased level of abnormal hematology measures detectable in routine medical surveillance.

  16. Tributyltin exposure alters cytokine levels in mouse serum.

    PubMed

    Lawrence, Shanieek; Pellom, Samuel T; Shanker, Anil; Whalen, Margaret M

    2016-11-01

    Tributyltin (TBT), a toxic environmental contaminant, has been widely utilized for various industrial, agricultural and household purposes. Its usage has led to a global contamination and its bioaccumulation in aquatic organisms and terrestrial mammals. Previous studies suggest that TBT has debilitating effects on the overall immune function of animals, rendering them more vulnerable to diseases. TBT (at concentrations that have been detected in human blood) alters secretion of inflammatory cytokines from human lymphocytes ex vivo. Thus, it is important to determine if specified levels of TBT can alter levels of cytokines in an in vivo system. Mice were exposed to biologically relevant concentrations of TBT (200, 100 or 25 nM final concentrations). The quantitative determination of interferon (IFN)-γ, tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL2, IL5, IL7, IL12βp40, IL13, IL15, keratinocyte chemoattractant (KC), macrophage inflammatory protein 1β (MIP), MIP2 and regulated on activation normal T-cell-expressed and secreted (RANTES) was performed in mouse sera by MAGPIX analysis and Western blot. Results indicated alterations (both decreases and increases) in several cytokines. The pro-inflammatory cytokines IFNγ, TNFα, IL-1β, IL-2, IL5, IL12βp40 and IL-15 were altered as were the chemokines MIP-1 and RANTES and the anti-inflammatory cytokine IL-13. Increases in IFNγ and TNFα were seen in the serum of mice exposed to TBT for less than 24 h. Levels of IL1β, IL-12 βp40, IL-5 and IL-15 were also modulated in mouse serum, depending on the specific experiment and exposure level. IL-2 was consistently decreased in mouse serum when animals were exposed to TBT. There were also TBT-induced increases in MIP-1β, RANTES and IL-13. These results from human and murine samples clearly suggest that TBT exposures modulate the secretion inflammatory cytokines.

  17. Aggregation of exposure level and probability into a single metric in job-exposure matrices creates bias.

    PubMed

    Burstyn, Igor; Lavoué, Jérôme; Van Tongeren, Martie

    2012-11-01

    Job-exposure matrices (JEMs) are often used in occupational epidemiological studies to provide an exposure estimate for a typical person in a 'job' during a particular time period. A JEM can produce exposure estimates on a variety of scales, such as (but not limited to) binary assessments of presence or absence of exposure, ordinal ranking of exposure level and frequency, and quantitative exposure estimates of exposure intensity and frequency. Specifically, one popular approach to construct a JEM, engendered in a Finnish job exposure matrix (FINJEM), provides a probability that a worker within an occupational group is exposed and an estimate of intensity of exposure among the exposed workers within this occupation. Often the product of the probability and intensity (aka level) is used to obtain the estimate of exposure for the epidemiological analyses. This procedure aggregates exposure across exposed and non-exposed individuals and the effect of this particular procedure on epidemiological analyses has never been studied. We developed a theoretical framework for understanding how these aggregate exposure estimates relate to true exposure (either unexposed or log-normally distributed for 'exposed'), assuming that there is no uncertainty about estimates of level and probability of exposure. Theoretical derivations show that multiplying occupation-specific exposure level and probability of non-zero exposure results in both systematic and differential measurement errors. Simulations demonstrated that under certain conditions bias in odds ratios in a cohort study away from the null are possible and that this bias is smaller when (a) arithmetic rather than geometric mean is used to assess exposure level and (b) exposure level and prevalence are positively correlated. We illustrate the potential impact of using the specified JEM in a simulation based on a case-control study of non-Hodgkin lymphoma and exposure to ionizing and non-ionizing radiation. Inflation of standard

  18. Prenatal low-level mercury exposure and neonatal anthropometry in rural northern China.

    PubMed

    Ding, Guodong; Cui, Chang; Chen, Limei; Gao, Yu; Zhou, Yijun; Shi, Rong; Tian, Ying

    2013-08-01

    Mercury (Hg) is a ubiquitous heavy metal that can negatively affect human health; however, few studies have examined the impact of prenatal low-level Hg exposure on fetal growth. We investigated prenatal exposure levels of Hg and the relationship between Hg levels and neonatal anthropometrics, including birth weight, length, and head circumference. A total of 258 mother-infant pairs were recruited from a rural community located on the southern coastal area of Laizhou Bay of the Bohai Sea in northern China between September 2010 and December 2011. We measured maternal and cord whole blood Hg levels and examined their association with neonatal anthropometrics. The geometric means (GMs) of Hg in maternal and cord whole blood were 0.84μgL(-1) and 1.46μgL(-1), respectively. The Hg exposure levels in our study population were much lower than those reported in previous domestic studies. No significant associations were found between maternal or cord blood Hg levels and birth weight, length, and head circumference. However, our results should be interpreted with caution given the high toxicity of Hg and its persistence in the body. Studies focusing on long-term adverse outcomes are needed to further examine the cumulative effects of low-level Hg exposure.

  19. Evaluation of noise pollution level based upon community exposure and response data

    NASA Technical Reports Server (NTRS)

    Edmiston, R. D.

    1972-01-01

    The results and procedures are reported from an evaluation of noise pollution level as a predictor of annoyance, based on aircraft noise exposure and community response data. The measures of noise exposure presented include composite noise rating, noise exposure forecast, noise and number index. A proposed measure as a universal noise exposure measure for noise pollution level (L sub NP) is discussed.

  20. Can low level exposure to ochratoxin-A cause parkinsonism?

    PubMed

    Sava, V; Reunova, O; Velasquez, A; Sanchez-Ramos, J

    2006-11-01

    Mycotoxins are fungal metabolites with pharmacological activities that have been utilized in the production of antibiotics, growth promoters, and other classes of drugs. Some mycotoxins have been developed as biological and chemical warfare agents. Bombs and ballistic missiles loaded with aflatoxin were stockpiled and may have been deployed by Iraq during the first Gulf War. In light of the excess incidence of amyotrophic lateral sclerosis (ALS) in veterans from Operation Desert Storm, the potential for delayed neurotoxic effects of low doses of mycotoxins should not be overlooked. Ochratoxin-A (OTA) is a common mycotoxin with complex mechanisms of action, similar to that of the aflatoxins. Acute administration of OTA at non-lethal doses (10% of the LD(50)) have been shown to increase oxidative DNA damage in brain up to 72 h, with peak effects noted at 24 h in midbrain (MB), caudate/putamen (CP) and hippocampus (HP). Levels of dopamine (DA) and its metabolites in the striatum (e.g., CP) were shown to be decreased in a dose-dependent manner. The present study focused on the effects of chronic low dose OTA exposure on regional brain oxidative stress and striatal DA metabolism. Continuous administration of low doses of OTA with implanted subcutaneous Alzet minipumps caused a small but significant decrease in striatal DA levels and an upregulation of anti-oxidative systems and DNA repair. It is possible that low dose exposure to OTA will result in an earlier onset of parkinsonism when normal age-dependent decline in striatal DA levels are superimposed on the mycotoxin-induced lesion.

  1. Low-level cadmium exposure and effects on kidney function.

    PubMed

    Wallin, Maria; Sallsten, Gerd; Lundh, Thomas; Barregard, Lars

    2014-12-01

    The nephrotoxicity of cadmium at low levels of exposure, measured by urinary cadmium, has recently been questioned since co-excretion of cadmium and proteins may have causes other than cadmium toxicity. The aim of this study was to explore the relation between kidney function and low or moderate cadmium levels, measured directly in kidney biopsies. We analysed cadmium in kidney biopsies (K-Cd), blood (B-Cd) and urine (U-Cd) from 109 living kidney donors in a cross-sectional study. We measured glomerular filtration rate (GFR), cystatin C in serum, albumin, β-2-microglobulin (B2M), retinol-binding protein (RBP), α-1-microglobulin (A1M), N-acetyl-β-d-glucosaminidase and kidney injury molecule 1 (KIM-1) in 24 h and overnight urine. We found significant positive associations between A1M excretion and K-Cd in multiple regression models including age, sex, weight, smoking and urinary flow rate. This association was also present in never-smokers. A1M was also positively associated with B-Cd and U-Cd. GFR and the other biomarkers of kidney function were not associated with K-Cd. GFR estimated from serum cystatin C showed a very poor correlation with measured GFR. KIM-1, RBP and possibly albumin were positively associated with U-Cd, but only in overnight urine. No associations were found with B2M. Our results suggest that A1M in urine is a sensitive biomarker for effects of low-level cadmium exposure. A few associations between other renal biomarkers and U-Cd, but not K-Cd, were probably caused by physiological co-excretion or chance. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  2. Low-level cadmium exposure and effects on kidney function

    PubMed Central

    Wallin, Maria; Sallsten, Gerd; Lundh, Thomas; Barregard, Lars

    2014-01-01

    Objectives The nephrotoxicity of cadmium at low levels of exposure, measured by urinary cadmium, has recently been questioned since co-excretion of cadmium and proteins may have causes other than cadmium toxicity. The aim of this study was to explore the relation between kidney function and low or moderate cadmium levels, measured directly in kidney biopsies. Methods We analysed cadmium in kidney biopsies (K-Cd), blood (B-Cd) and urine (U-Cd) from 109 living kidney donors in a cross-sectional study. We measured glomerular filtration rate (GFR), cystatin C in serum, albumin, β-2-microglobulin (B2M), retinol-binding protein (RBP), α-1-microglobulin (A1M), N-acetyl-β-d-glucosaminidase and kidney injury molecule 1 (KIM-1) in 24 h and overnight urine. Results We found significant positive associations between A1M excretion and K-Cd in multiple regression models including age, sex, weight, smoking and urinary flow rate. This association was also present in never-smokers. A1M was also positively associated with B-Cd and U-Cd. GFR and the other biomarkers of kidney function were not associated with K-Cd. GFR estimated from serum cystatin C showed a very poor correlation with measured GFR. KIM-1, RBP and possibly albumin were positively associated with U-Cd, but only in overnight urine. No associations were found with B2M. Conclusions Our results suggest that A1M in urine is a sensitive biomarker for effects of low-level cadmium exposure. A few associations between other renal biomarkers and U-Cd, but not K-Cd, were probably caused by physiological co-excretion or chance. PMID:25286916

  3. Biological monitoring of low-level exposure to benzene.

    PubMed

    Campagna, M; Satta, Giannina; Campo, Laura; Flore, Valeria; Ibba, A; Meloni, M; Tocco, Maria Giuseppina; Avataneo, G; Flore, C; Fustinoni, Silvia; Cocco, P

    2012-01-01

    Conflicting opinions exist about the reliability of biomarkers of low-level exposure to benzene. We compared the ability of the urinary excretion of trans,trans-muconic acid (t,t-MA), s-phenilmercapturic acid (s-PAMA) and urinary benzene (U-Benz) to detect low level occupational and environmental exposure to benzene. We monitored airborne benzene by personal air sampling, and U-Benz, s-PMAI, t,t-MA and cotinine (U-Cotinine) in spot urine samples, collected at 8 am and 8 pm, in 32 oil refinery workers and 65 subjects, randomly selected among the general population of urban and suburban Cagliari, Italy. Information on personal characteristics, diet and events during the sampling day was acquired through in person interviews. The median concentration of airborne benzene was 25.2 microg/m3 in oil refinery workers, and 8.5 microg/m3 in the general population subgroup. U-Benz in morning and evening samples was significantly more elevated among oil refinery workers than the general population subgroup (p = 0.012, and p = 7.4 x 10(-7), respectively) and among current smokers compared to non-smokers (p = 5.2 x 10(-8), and p = 5.2 x 10(-5) respectively). Benzene biomarkers and their readings in the two sampling phases were well correlated to each other. The Spearman's correlation coefficient with airborne benzene was significant for U-Benz in the evening sample, while no correlation was seen with t,t-MA and s-PMA readings in either samplings. The two benzene metabolites were frequently below limit of detection (LOD), particularly among the general population study subjects (17-9% and 39%, for t,t-MA and s-PMA respectively). Morning U-Cotinine excretion showed a good correlation with U-Benz in the morning and in the evening sampling (p < 0.001), and with s-PMA in the evening sample (p < 0.001), but not with t,t-MA in either samplings. t,t-MA in the evening sample was the only biomarker showing a moderate inverse correlation with BMI (p < 0.05). The multiple regression

  4. Swelling of Uranium Alloys at High Exposures

    SciTech Connect

    McDonell, W.R.

    2001-03-26

    This reports summarizes the results of postirradiation examinations of a series of unrestrained dilute uranium alloy specimens irradiated to exposures up to 13,000 MWD/T in NaK-containing stainless steel capsules.

  5. Is Sound Exposure Level a Convenient Metric to Characterize Fatiguing Sounds? A Study in Beluga Whales.

    PubMed

    Supin, Alexander; Popov, Vladimir; Nechaev, Dmitry; Sysueva, Evgenia; Rozhnov, Viatcheslav

    2016-01-01

    Both the level and duration of fatiguing sounds influence temporary threshold shifts (TTSs) in odontocetes. These two parameters were combined into a sound exposure level (SEL). In the beluga whale Delphinapterus leucas, TTSs were investigated at various sound pressure level (SPL)-to-duration ratios at a specific SEL. At low SPL-to-duration ratios, the dependence was positive: shorter high-level sounds produced greater TTSs than long low-level sounds of the same SEL. At high SPL-to-duration ratios, the dependence was negative: long low-level sounds produced greater TTSs than short high-level sounds of the same SEL. Thus, the validity of SEL as a metric for fatiguing sound efficiency is limited.

  6. High-Level Connectionist Models

    DTIC Science & Technology

    1989-08-01

    respec- 3 tively for determiner, adjective, noun, verb, and preposition. Consider a simple context- free grammar , where every rule expansion has exactly... grammar , it is easy to derive the bracketed binary trees which will make up a training set. With one such set of strings, a 3 chart parser yielded...PARSNIP: A connectionist network that learns natural language grammar from exposure to natural language sentences, Proceedings of the Ninth Conference of

  7. Low-level arsenic exposure in wood processing plants.

    PubMed

    Rosenberg, M J; Landrigan, P J; Crowley, S

    1980-01-01

    In October 1978, seven construction workers building a pier in Monterey, California, developed symptoms consistent with arsenic intoxication and had elevated urinary levels of arsenic. The wood used for the pier had been pressure-treated with an arsenic preservative. To evaluate the potential acute medical hazards of preserving wood with arsenic, we evaluated employees at three California plants where arsenic preservatives are mixed and applied to wood. Histories, physical examinations, and urine specimens for arsenic analysis were collected from 44 workers exposed to arsenic and from 37 controls in three woodworking plants where arsenic is not used. A comparison of the groups failed to show any significant differences in history or physical examination. Adjustment for age, length of employment, and smoking histories did not alter the pattern. Urinary arsenic concentration was found to increase with increased exposure. These results do not imply absence of chronic or delayed toxicity, nor do they preclude the presence of a more subtle toxicity such as nerve conduction deficits. The data indicate existence of an arsenic exposure hazard in wood processing.U

  8. Mercury Exposure May Suppress Baseline Corticosterone Levels in Juvenile Birds.

    USGS Publications Warehouse

    Herring, Garth; Ackerman, Joshua T.; Herzog, Mark P.

    2012-01-01

    Mercury exposure has been associated with a wide variety of negative reproductive responses in birds, however few studies have examined the potential for chick impairment via the hypothalamic-pituitary-adrenal (HPA) axis. The HPA axis regulates corticosterone levels during periods of stress. We examined the relationship between baseline fecal corticosterone metabolite concentrations and mercury concentrations in down feathers of recently hatched (Sterna forsteri) chicks in San Francisco Bay, California. Baseline fecal corticosterone metabolite concentrations were negatively correlated with mercury concentrations in blood of older chicks (decreasing by 81% across the range of observed mercury concentrations) while accounting for positive correlations between corticosterone concentrations and number of fledgling chicks within the colony and chick age. In recently hatched chicks, baseline fecal corticosterone metabolite concentrations were weakly negatively correlated with mercury concentrations in down feathers (decreasing by 45% across the range of observed mercury concentrations) while accounting for stronger positive correlations between corticosterone concentrations and colony nest abundance and date. These results indicate that chronic mercury exposure may suppress baseline corticosterone concentrations in tern chicks and suggests that a juvenile bird's ability to respond to stress may be reduced via the downregulation of the HPA axis.

  9. Exposure to a Highly Caloric Palatable Diet During Pregestational and Gestational Periods Affects Hypothalamic and Hippocampal Endocannabinoid Levels at Birth and Induces Adiposity and Anxiety-Like Behaviors in Male Rat Offspring.

    PubMed

    Ramírez-López, María Teresa; Vázquez, Mariam; Bindila, Laura; Lomazzo, Ermelinda; Hofmann, Clementine; Blanco, Rosario Noemí; Alén, Francisco; Antón, María; Decara, Juan; Ouro, Daniel; Orio, Laura; Suarez, Juan; Lutz, Beat; Rodríguez de Fonseca, Fernando; Gómez de Heras, Raquel

    2015-01-01

    Exposure to unbalanced diets during pre-gestational and gestational periods may result in long-term alterations in metabolism and behavior. The contribution of the endocannabinoid system to these long-term adaptive responses is unknown. In the present study, we investigated the impact of female rat exposure to a hypercaloric-hypoproteic palatable diet during pre-gestational, gestational and lactational periods on the development of male offspring. In addition, the hypothalamic and hippocampal endocannabinoid contents at birth and the behavioral performance in adulthood were investigated. Exposure to a palatable diet resulted in low weight offspring who exhibited low hypothalamic contents of arachidonic acid and the two major endocannabinoids (anandamide and 2-arachidonoylglycerol) at birth. Palmitoylethanolamide, but not oleoylethanolamide, also decreased. Additionally, pups from palatable diet-fed dams displayed lower levels of anandamide and palmitoylethanolamide in the hippocampus. The low-weight male offspring, born from palatable diet exposed mothers, gained less weight during lactation and although they recovered weight during the post-weaning period, they developed abdominal adiposity in adulthood. These animals exhibited anxiety-like behavior in the elevated plus-maze and open field test and a low preference for a chocolate diet in a food preference test, indicating that maternal exposure to a hypercaloric diet induces long-term behavioral alterations in male offspring. These results suggest that maternal diet alterations in the function of the endogenous cannabinoid system can mediate the observed phenotype of the offspring, since both hypothalamic and hippocampal endocannabinoids regulate feeding, metabolic adaptions to caloric diets, learning, memory, and emotions.

  10. Exposure to a Highly Caloric Palatable Diet During Pregestational and Gestational Periods Affects Hypothalamic and Hippocampal Endocannabinoid Levels at Birth and Induces Adiposity and Anxiety-Like Behaviors in Male Rat Offspring

    PubMed Central

    Ramírez-López, María Teresa; Vázquez, Mariam; Bindila, Laura; Lomazzo, Ermelinda; Hofmann, Clementine; Blanco, Rosario Noemí; Alén, Francisco; Antón, María; Decara, Juan; Ouro, Daniel; Orio, Laura; Suarez, Juan; Lutz, Beat; Rodríguez de Fonseca, Fernando; Gómez de Heras, Raquel

    2016-01-01

    Exposure to unbalanced diets during pre-gestational and gestational periods may result in long-term alterations in metabolism and behavior. The contribution of the endocannabinoid system to these long-term adaptive responses is unknown. In the present study, we investigated the impact of female rat exposure to a hypercaloric-hypoproteic palatable diet during pre-gestational, gestational and lactational periods on the development of male offspring. In addition, the hypothalamic and hippocampal endocannabinoid contents at birth and the behavioral performance in adulthood were investigated. Exposure to a palatable diet resulted in low weight offspring who exhibited low hypothalamic contents of arachidonic acid and the two major endocannabinoids (anandamide and 2-arachidonoylglycerol) at birth. Palmitoylethanolamide, but not oleoylethanolamide, also decreased. Additionally, pups from palatable diet-fed dams displayed lower levels of anandamide and palmitoylethanolamide in the hippocampus. The low-weight male offspring, born from palatable diet exposed mothers, gained less weight during lactation and although they recovered weight during the post-weaning period, they developed abdominal adiposity in adulthood. These animals exhibited anxiety-like behavior in the elevated plus-maze and open field test and a low preference for a chocolate diet in a food preference test, indicating that maternal exposure to a hypercaloric diet induces long-term behavioral alterations in male offspring. These results suggest that maternal diet alterations in the function of the endogenous cannabinoid system can mediate the observed phenotype of the offspring, since both hypothalamic and hippocampal endocannabinoids regulate feeding, metabolic adaptions to caloric diets, learning, memory, and emotions. PMID:26778987

  11. Polychlorinated biphenyl exposure and corticosterone levels in seven polar seabird species.

    PubMed

    Tartu, S; Angelier, F; Bustnes, J O; Moe, B; Hanssen, S A; Herzke, D; Gabrielsen, G W; Verboven, N; Verreault, J; Labadie, P; Budzinski, H; Wingfield, J C; Chastel, O

    2015-02-01

    The role of polychlorinated biphenyls (PCBs) on exposure-related endocrine effects has been poorly investigated in wild birds. This is the case for stress hormones including corticosterone (CORT). Some studies have suggested that environmental exposure to PCBs and altered CORT secretion might be associated. Here we investigated the relationships between blood PCB concentrations and circulating CORT levels in seven free-ranging polar seabird species occupying different trophic positions, and hence covering a wide range of PCB exposure. Blood ∑₇PCB concentrations (range: 61-115,632 ng/g lw) were positively associated to baseline or stress-induced CORT levels in three species and negatively associated to stress-induced CORT levels in one species. Global analysis suggests that in males, baseline CORT levels generally increase with increasing blood ∑₇PCB concentrations, whereas stress-induced CORT levels decrease when reaching high blood ∑₇PCB concentrations. This study suggests that the nature of the PCB-CORT relationships may depend on the level of PCB exposure.

  12. HELLE: Health Effects of Low Level Exposures/ Gezondheidseffecten van lage blootstellingniveaus [International workshop: Influence of low level exposures to chemicals and radiation on human and ecological health

    SciTech Connect

    Schoten, Eert

    1998-11-26

    The Health Council is closely involved in establishing the scientific foundation of exposure limits for substances and radiation in order to protect public health. Through the years, the Council has contributed to the formulation of principles and procedures, both for carcinogenic and for noncarcinogenic agents. As a rule, the discussion with regard to the derivation of health-based recommended exposure limits centers around the appropriateness of extrapolation methods (What can be inferred from data on high exposure levels and on experimental animals?). Generally speaking, there is a lack of direct information on the health effects of low levels of exposure. Effects at these levels cannot usually be detected by means of traditional animal experiments or epidemiological research. The capacity of these analytical instruments to distinguish between ''signal'' and ''noise'' is inadequate in most cases. Annex B of this report contains a brief outline of the difficulties and the established methods for tackling this problem. In spite of this, the hope exists that the posited weak signals, if they are indeed present, can be detected by other means. The search will have to take place on a deeper level. In other words, effort must be made to discover what occurs at underlying levels of biological organization when organisms are exposed to low doses of radiation or substances. Molecular and cell biology provide various methods and techniques which give an insight into the processes within the cell. This results in an increase in the knowledge about the molecular and cellular effects of exposure to agents, or stated differently, the working mechanisms which form the basis of the health effects. Last year, the Health Council considered that the time was ripe to take stock of the state of knowledge in this field. To this end, an international working conference was held from 19 to 21 October 1997, entitled ''Health Effects of Low Level Exposures: Scientific Developments and

  13. High level white noise generator

    DOEpatents

    Borkowski, Casimer J.; Blalock, Theron V.

    1979-01-01

    A wide band, stable, random noise source with a high and well-defined output power spectral density is provided which may be used for accurate calibration of Johnson Noise Power Thermometers (JNPT) and other applications requiring a stable, wide band, well-defined noise power spectral density. The noise source is based on the fact that the open-circuit thermal noise voltage of a feedback resistor, connecting the output to the input of a special inverting amplifier, is available at the amplifier output from an equivalent low output impedance caused by the feedback mechanism. The noise power spectral density level at the noise source output is equivalent to the density of the open-circuit thermal noise or a 100 ohm resistor at a temperature of approximately 64,000 Kelvins. The noise source has an output power spectral density that is flat to within 0.1% (0.0043 db) in the frequency range of from 1 KHz to 100 KHz which brackets typical passbands of the signal-processing channels of JNPT's. Two embodiments, one of higher accuracy that is suitable for use as a standards instrument and another that is particularly adapted for ambient temperature operation, are illustrated in this application.

  14. Modelling of radiation exposure at high altitudes during solar storms.

    PubMed

    Al Anid, H; Lewis, B J; Bennett, L G I; Takada, M

    2009-10-01

    A transport code analysis using Monte Carlo N-Particle eXtended code, MCNPX, has been used to propagate an extrapolated particle spectrum based on satellite measurements through the atmosphere to estimate radiation exposure during solar storms at high altitudes. Neutron monitor count rate data from stations around the world were used to benchmark the model calculations during a ground-level event (GLE). A comparison was made between the model predictions and actual flight measurements taken with various types of instruments used to measure the mixed radiation field during GLE 60. A computer code has been developed to implement the model for routine analysis.

  15. Welding-related brain and functional changes in welders with chronic and low-level exposure.

    PubMed

    Lee, Eun-Young; Flynn, Michael R; Lewis, Mechelle M; Mailman, Richard B; Huang, Xuemei

    2017-06-23

    Although an essential nutrient, manganese (Mn) can be toxic at high doses. There is, however, uncertainty regarding the effects of chronic low-level Mn-exposure. This review provides an overview of Mn-related brain and functional changes based on studies of a cohort of asymptomatic welders who had lower Mn-exposure than in most previous work. In welders with low-level Mn-exposure, we found: 1) Mn may accumulate in the brain in a non-linear fashion: MRI R1 (1/T1) signals significantly increased only after a critical level of exposure was reached (e.g., ≥300 welding hours in the past 90days prior to MRI). Moreover, R1 may be a more sensitive marker to capture short-term dynamic changes in Mn accumulation than the pallidal index [T1-weighted intensity ratio of the globus pallidus vs. frontal white matter], a traditional marker for Mn accumulation; 2) Chronic Mn-exposure may lead to microstructural changes as indicated by lower diffusion tensor fractional anisotropy values in the basal ganglia (BG), especially when welding years exceeded more than 30 years; 3) Mn-related subtle motor dysfunctions can be captured sensitively by synergy metrics (indices for movement stability), whereas traditional fine motor tasks failed to detect any significant differences; and 4) Iron (Fe) also may play a role in welding-related neurotoxicity, especially at low-level Mn-exposure, evidenced by higher R2* values (an estimate for brain Fe accumulation) in the BG. Moreover, higher R2* values were associated with lower phonemic fluency performance. These findings may guide future studies and the development of occupation- and public health-related polices involving Mn-exposure. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Fine particle (PM2.5) personal exposure levels in transport microenvironments, London, UK.

    PubMed

    Adams, H S; Nieuwenhuijsen, M J; Colvile, R N; McMullen, M A; Khandelwal, P

    2001-11-12

    In order to investigate a specific area of short-term, non-occupational, human exposure to fine particulate air pollution, measurements of personal exposure to PM2.5 in transport microenvironments were taken in two separate field studies in central London, UK. A high flow gravimetric personal sampling system was used; operating at 16 l min(-1); the sampler thus allowed for sufficient sample mass collection for accurate gravimetric analysis of short-term travel exposure levels over typical single commute times. In total, samples were taken on 465 journeys and 61 volunteers participated. In a multi-transport mode study, carried out over 3-week periods in the winter and in the summer, exposure levels were assessed along three fixed routes at peak and off-peak times of the day. Geometric means of personal exposure levels were 34.5 microg m(-3) (G.S.D.= 1.7, n(s) = 40), 39.0 microg m(-3) (G.S.D. = 1.8, n(s) = 36), 37.7 microg m(-3) (G.S.D. = 1.5, n(s) = 42), and 247.2 microg m(-3) (G.S.D. = 1.3, n(s) = 44) for bicycle, bus, car and Tube (underground rail system) modes, respectively, in the July 1999 (summer) measurement campaign. Corresponding levels in the February 2000 (winter) measurement campaign were 23.5 microg m(-3) (G.S.D. = 1.8, n(s) = 56), 38.9 microg m(-3) (G.S.D. = 2.1, n(s) = 32), 33.7 microg m(-3) (G.S.D. = 2.4, n(s) = 12), and 157.3 microg m(-3) (G.S.D. = 3.3, n(s) = 12), respectively. In a second study, exposure levels were measured for a group of 24 commuters travelling by bicycle, during August 1999, in order to assess how representative the fixed route studies were to a larger commuter population. The geometric mean exposure level was 34.2 microg m(-3) (G.S.D. = 1.9, n(s) = 105). In the fixed-route study, the cyclists had the lowest exposure levels, bus and car were slightly higher, while mean exposure levels on the London Underground rail system were 3-8 times higher than the surface transport modes. There was significant between-route variation

  17. Significance of smoking machine toxicant yields to blood-level exposure in water pipe tobacco smokers.

    PubMed

    Shihadeh, Alan L; Eissenberg, Thomas E

    2011-11-01

    The global increase in tobacco smoking with a water pipe (hookah, narghile, or shisha) has made understanding its health consequences imperative. One key to developing this understanding is identifying and quantifying carcinogens and other toxicants present in water pipe smoke. To do so, the toxicant yield of machine-generated water pipe smoke has been measured. However, the relevance of toxicant yields of machine-generated smoke to actual human exposure has not been established. In this study, we examined whether carbon monoxide (CO) and nicotine yields measured with a smoking machine programmed to replicate the puffing behavior of 31 human participants who smoked a water pipe could reliably predict these participants' blood-level exposure. In addition to CO and nicotine, yields of polyaromatic hydrocarbons, volatile aldehydes, nitric oxide (NO), and "tar" were measured. We found that when used in this puff-replicating manner, smoking machine yields are highly correlated with blood-level exposure (nicotine: r > 0.76, P < 0.001; CO: r > 0.78, P < 0.001). Total drawn smoke volume was the best predictor of toxicant yield and exposure, accounting for approximately 75% to 100% of the variability across participants in yields of NO, CO, volatile aldehydes, and tar, as well as blood-level CO and normalized nicotine. Machine-based methods can be devised in which smoke toxicant yields reliably track human exposure. This finding indicates the basic feasibility of valid analytic laboratory evaluation of tobacco products for regulatory purposes. © 2011 AACR.

  18. Significance of smoking machine toxicant yields to blood-level exposure in waterpipe tobacco smokers

    PubMed Central

    Shihadeh, Alan L.; Eissenberg, Thomas E.

    2014-01-01

    Background The global rise in tobacco smoking using a waterpipe (hookah, narghile, shisha) has made understanding its health consequences imperative. One key to developing this understanding is identifying and quantifying carcinogens and other toxicants present in waterpipe smoke. To do so, the toxicant yield of machine-generated waterpipe smoke has been measured. However, the relevance of toxicant yields of machine-generated smoke to actual human exposure has not been established. Methods In this study, we examined whether CO and nicotine yields measured using a smoking machine programmed to replicate the puffing behavior of 31 human participants who smoked a waterpipe could reliably predict these participant’s blood-level exposure. In addition to CO and nicotine, yields of PAH, volatile aldehydes, NO, and “tar” were measured. Results We found that when used in this puff-replicating manner, smoking machine yields are highly correlated with blood-level exposure (Nicotine: r>0.76, p<0.001; CO: r>0.78, p<0.001). Total drawn smoke volume was the best predictor of toxicant yield and exposure, accounting for approximately 75–100% of the variability across participants in yields of NO, CO, volatile aldehydes and “tar”, and blood-level CO and normalized nicotine. Conclusions Machine-based methods can be devised in which smoke toxicant yields reliably track human exposure. Impact This finding indicates the basic feasibility of valid analytical laboratory evaluation of tobacco products for regulatory purposes. PMID:21914836

  19. Optimizing High Level Waste Disposal

    SciTech Connect

    Dirk Gombert

    2005-09-01

    If society is ever to reap the potential benefits of nuclear energy, technologists must close the fuel-cycle completely. A closed cycle equates to a continued supply of fuel and safe reactors, but also reliable and comprehensive closure of waste issues. High level waste (HLW) disposal in borosilicate glass (BSG) is based on 1970s era evaluations. This host matrix is very adaptable to sequestering a wide variety of radionuclides found in raffinates from spent fuel reprocessing. However, it is now known that the current system is far from optimal for disposal of the diverse HLW streams, and proven alternatives are available to reduce costs by billions of dollars. The basis for HLW disposal should be reassessed to consider extensive waste form and process technology research and development efforts, which have been conducted by the United States Department of Energy (USDOE), international agencies and the private sector. Matching the waste form to the waste chemistry and using currently available technology could increase the waste content in waste forms to 50% or more and double processing rates. Optimization of the HLW disposal system would accelerate HLW disposition and increase repository capacity. This does not necessarily require developing new waste forms, the emphasis should be on qualifying existing matrices to demonstrate protection equal to or better than the baseline glass performance. Also, this proposed effort does not necessarily require developing new technology concepts. The emphasis is on demonstrating existing technology that is clearly better (reliability, productivity, cost) than current technology, and justifying its use in future facilities or retrofitted facilities. Higher waste processing and disposal efficiency can be realized by performing the engineering analyses and trade-studies necessary to select the most efficient methods for processing the full spectrum of wastes across the nuclear complex. This paper will describe technologies being

  20. Cardiovascular actions of cadmium at environmental exposure levels

    SciTech Connect

    Kopp, S.J.; Glonek, T.; Perry, H.M. Jr.; Erlanger, M.; Perry, E.F.

    1982-08-27

    A low intake of dietary cadmium induces specific dose-dependent functional and biochemical changes in the cardiovascular tissues of rats. Maximum changes occur when the cadmium intake is 10 to 20 micrograms per kilogram of body weight per day. The changes reflect the accumulation of critical concentrations of cadmium in the cardiovascular tissues. The biologic activity of cadmium is demonstrated for intakes that approach those of the average American adult exposed to the usual environmental concentrations of the element but not to industrial concentrations. The sensitivity of the cardiovascular system to low doses of cadmium could not be anticipated by extrapolation from data on exposure to high concentrations of cadmium. The data support the hypothesis that ingested or inhaled environmental cadmium may contribute to essential hypertension in humans.

  1. Change in childhood lead exposure prevalence with new reference level.

    PubMed

    Leafe, Morgan; Irigoyen, Matilde; DeLago, Cynthia; Hassan, Amman; Braitman, Leonard

    2015-06-01

    In 2012, the Centers for Disease Control and Prevention changed the "actionable" reference blood lead level from 10 μg/dL to 5 μg/dL, representing the highest 2.5 percentile of lead levels nationwide. In a high-risk urban community, the prevalence of children classified as lead exposed increased ninefold, from 1% to 9.1% (p < .0001) with the new reference level. This dramatic increase in the prevalence of children newly classified as lead exposed will require additional health care and public health resources for tracking, surveillance, and home lead abatement.

  2. Adverse effects of low level heavy metal exposure on male reproductive function.

    PubMed

    Wirth, Julia J; Mijal, Renée S

    2010-04-01

    Lead, cadmium, mercury, and arsenic, often referred to as "heavy metals", are toxic for wildlife, experimental animals, and humans. While experimental animal and human occupational studies with high exposure levels generally support an adverse role for these metals in human reproductive outcomes, information on the effects of low, environmentally-realistic exposure levels of these metals on male reproductive outcomes is limited. We review the literature on effects of exposure to low levels of these metals on measures of male fertility (semen quality and reproductive hormone levels) and provide supporting evidence from experimental and occupational studies. Potentially modifying effects of genetic polymorphisms on these associations are discussed. A brief review of the literature on the effects of three trace metals, copper, manganese, and molybdenum, that are required for human health, yet may also cause adverse reproductive effects, follows. Overall, there were few studies examining the effects of exposure to low levels of these metals on male reproductive health. For all metals, there were several well-designed studies with sufficient populations appropriately adjusted for potential confounders and many of these reported harmful effects. However, many studies lacked sufficient numbers of participants to be able to detect differences in outcomes between exposed and non-exposed individuals, did not clearly identify the source and characteristics of the participants, and did not control for other exposures that could alter or contribute to the outcomes. The evidence for the effects of low exposure was strongest for cadmium, lead, and mercury and less certain for arsenic. The potential modifying effects of genetic polymorphisms has not been fully explored. Additional studies on the reproductive effects of these toxic ubiquitous metals on male reproduction are required to expand the knowledge base and to resolve inconsistencies.

  3. In vivo cGMP levels in frog photoreceptor cells as a function of light exposure.

    PubMed

    Barbehenn, E K; Klotz, K L; Noelker, D M; Nelson, R; Chader, G J; Passonneau, J V

    1986-11-01

    By employing a combination of highly sensitive radioimmunoassays and histochemical techniques, an in vivo time course of cGMP levels has been determined in the outer segment, photoreceptor cell and outer plexiform layers of frog retina. Frogs (Rana pipiens) were dark-adapted overnight and either frozen rapidly (approximately 3 sec) in liquid nitrogen or exposed to periods of light varying between 0.1 sec and 2 hr before freezing. Frozen retinal sections were cut, freeze-dried, and samples of individual layers dissected out and analysed for cGMP. In the outer plexiform layer, there was a 42% drop in cGMP concentration after 2 sec of light (250 ft candles) followed by a 34% rise after 2 min; a steep concentration gradient formed around the layer after the 2 min exposure. In both the outer-segment layer and photoreceptor-cell layer (which includes outer segments, inner segments and outer nuclear layers), cGMP levels declined from a dark value of 56 mumol kg-1 (dry) to 9 mumol kg-1 (dry) as a result of increasing exposure to several types of light source: levels appear to be primarily a function of total ft candle min. Cyclic GMP concentrations at the longest exposures (2 min with a fiber optic light source or 2 hr with fluorescent room light) reached identical minimum levels. In the outer segments, a 15% decrease in cGMP was observed after 0.1 sec of light exposure. Although the freezing time is too long to be able to say whether the 15% decrease in cGMP at the 0.1 sec exposure is involved in transduction, the low identical levels reached gradually after longer exposures appear to indicate that a light-induced biochemical adjustment in cGMP metabolism occurs over a relatively long time period separate from the msec time course of the transduction process.

  4. Respiratory symptoms associated with low level sulphur dioxide exposure in silicon carbide production workers.

    PubMed Central

    Osterman, J W; Greaves, I A; Smith, T J; Hammond, S K; Robins, J M; Thériault, G

    1989-01-01

    Relations between pulmonary symptoms and exposure to respirable dust and sulphur dioxide (SO2) were evaluated for 145 silicon carbide (SiC) production workers with an average of 13.9 (range 3-41) years of experience in this industry. Eight hour time weighted average exposures to SO2 were 1.5 ppm or less with momentary peaks up to 4 ppm. Cumulative SO2 exposure averaged 1.94 (range 0.02-19.5) ppm-years. Low level respirable dust exposures also occurred (0.63 +/- 0.26 mg/m3). After adjusting for age and current smoking status in multiple logistic regression models, highly significant, positive, dose dependent relations were found between cumulative and average exposure to SO2, and symptoms of usual and chronic phlegm, usual and chronic wheeze, and mild exertional dyspnoea. Mild and moderate dyspnoea were also associated with most recent exposure to SO2. Cough was not associated with SO2. No pulmonary symptoms were associated with exposure to respirable dust nor were any symptoms attributable to an interaction between dust and SO2. Cigarette smoking was strongly associated with cough, phlegm, and wheezing, but not dyspnoea. A greater than additive (synergistic) effect between smoking and exposure to SO2 was present for most symptoms. These findings suggest that long term, variable exposure to SO2 at 1.5 ppm or less was associated with significantly raised rates of phlegm, wheezing, and mild dyspnoea in SiC production workers, and that current threshold limits for SO2 may not adequately protect workers in this industry. PMID:2789966

  5. Rhizobacterial glutathione levels as affected by starvation and cadmium exposure.

    PubMed

    Hultberg, M

    1998-11-01

    The rhizosphere is a continuously fluctuating environment in which severe stresses are put on its inhabitants, and glutathione, a reducing tripeptide, and related compounds probably have important roles in cellular protection. In the present study the metabolism of glutathione was examined in rhizobacteria subjected to stress. The plant-growth-promoting rhizobacterium Pseudomonas fluorescens 5.014 and its mutant 5-2/4 were exposed to starvation, either by resuspension or exhaustion, and to cadmium. Glutathione levels, cell protein, and viable count were determined and compared in different conditions. Both starvation and cadmium exposure decreased the amount of glutathione in the cell. No changes of the glutathione concentration in the medium were observed with or without the presence of rhizobacteria, indicating that there was no transport over the cell membrane. The glutathione levels within the rhizobacteria may give valuable information on how different stresses affect the bacteria. In this study, the involvement of glutathione in the increased stress resistance earlier observed in nutrient-starved P. fluorescens was not supported. The concentration of bacterial glutathione is suggested as a possible marker for rhizosphere competence, which, however, needs to be further evaluated with several strains of rhizobacteria.

  6. Low-level arsenic exposure from drinking water is associated with prostate cancer in Iowa.

    PubMed

    Roh, Taehyun; Lynch, Charles F; Weyer, Peter; Wang, Kai; Kelly, Kevin M; Ludewig, Gabriele

    2017-11-01

    Inorganic arsenic is a toxic naturally occurring element in soil and water in many regions of the US including the Midwest. Prostate cancer is the second most common type of cancer in men in Iowa, surpassed only by non-melanotic skin cancer. Epidemiology studies have evaluated arsenic exposure from drinking water and prostate cancer, but most have focused on high-level exposures outside the US. As drinking water from groundwater sources is a major source of arsenic exposure, we conducted an ecologic study to evaluate prostate cancer and arsenic in drinking water from public water sources and private wells in Iowa, where exposure levels are low, but duration of exposure can be long. Arsenic data from public water systems were obtained from the Iowa Safe Drinking Water Information System for the years 1994-2003 and for private wells from two Iowa Well Water Studies, the Iowa Community Private Well Study (ICPWS, 2002-2003) and Iowa Statewide Rural Well Water Survey Phase 2 (SWIRL2, 2006-2008) that provided data for 87 Iowa counties. Prostate cancer incidence data from 2009 to 2013 for Iowa were obtained from Surveillance, Epidemiology and End Results' SEER*Stat software. County averages of water arsenic levels varied from 1.08 to 18.6 ppb, with three counties above the current 10 ppb limit. Based on the tertiles of arsenic levels, counties were divided into three groups: low (1.08-2.06 ppb), medium (2.07-2.98 ppb), and high (2.99-18.6 ppb). Spatial Poisson regression modeling was conducted to estimate the risk ratios (RR) of prostate cancer by tertiles of arsenic level at a county level, adjusted for demographic and risk factors. The RR of prostate cancer were 1.23 (95% CI, 1.16-1.30) and 1.28 (95% CI, 1.21-1.35) in the medium and high groups, respectively, compared to the low group after adjusting for risk factors. The RR increased to 1.36 (95% CI, 1.28-1.45) in the high group when analyses were restricted to aggressive prostate cancers (Gleason score ≥ 7). This

  7. A low-level asbestos exposure case-control epidemiology study

    SciTech Connect

    Ocasio-Alvarex, A.

    1988-01-01

    The potential for low levels of airborne asbestos exposure in public schools and in public and commercial buildings in the United States has generated concern due to the large population at risk and the definite human carcinogenicity of asbestos at high levels. To assist in the clarification of the risk associated with low level asbestos exposure and in the decision-making in asbestos management in schools and in other buildings, a case-control study was conducted to estimate the risk relationship between low levels of asbestos exposure and pulmonary cancer among Indiana public school teachers. A total of 236 lung cancer cases and 154 controls to be used in this case-control study were identified from a previous proportionate mortality rate study which had examined over 8,000 teachers' death certificates. The controls were selected from teachers who died of chronic bronchitis, emphysema or a chronic obstructive pulmonary disease. The teachers' work history and their potential for asbestos exposure, as well as the reliability of the information obtained on the presence or absence of asbestos, was determined to calculate the odds ratio.

  8. Exposure levels for chemical threat compounds: information to facilitate chemical incident response.

    PubMed

    Hauschild, Veronique D; Watson, Annetta

    2013-01-01

    Although not widely known, a robust set of peer-reviewed public health and occupational exposure levels presently exist for key chemical warfare agents (CWAs) and certain acutely toxic industrial chemicals (TICs) identified as terrorist attack threats. Familiarity with these CWA and TIC exposure levels and their historic applications has facilitated emergency management decision-making by public and environmental health decision-makers. Specifically, multiple air, soil, and water exposure levels for CWAs and TICs summarized here have been extensively peer-reviewed and published; many have been recognized and are in use by federal and state health agencies as criteria for hazard zone prediction and assessment, occupational safety, and "how clean is clean enough" decisions. The key, however, is to know which criteria are most appropriate for specific decisions. While public safety is critical, high levels of concern often associated with perceived or actual proximity to extremely toxic chemical agents could result in overly cautious decisions that generate excessive delays, expenditure of scarce resources, and technological difficulties. Rapid selection of the most appropriate chemical exposure criteria is recommended to avoid such problems and expedite all phases of chemical incident response and recovery.

  9. Acute Exposure Guideline Levels (AEGLs) for Time Varying Toxic Plumes

    DTIC Science & Technology

    2014-09-12

    chemicals for a general population. Inhalation exposures in the real world, however, vary strongly in space and time and thus do not correspond to the...12-09-2014 Memorandum Report Toxic airborne contaminants Health effects prediction Space and time varying exposures Extension of EPA AEGLs 64-4464...few fixed-duration exposures to a few constant-density conditions are tabulated. The issue of how to treat real toxic plumes, whose agent density

  10. Assessing the Rapid Growth of Expected Coastal Flood Exposure Due to Sea Level Rise

    NASA Astrophysics Data System (ADS)

    Kulp, S. A.; Strauss, B.

    2016-12-01

    The impacts of rising sea levels can already be felt today, as storm tides reach extreme heights more frequently, thereby increasing the expected annual exposure (EAE) to coastal flooding experienced by many municipalities. While a number of earlier studies estimate the magnitude of flood exposure by certain dates, the rate at which exposure changes, which receives much less attention, is another critical factor in determining the costs and abilities of communities to adapt. Rates of escalating EAE do not correlate well with rates of SLR, and can change significantly over short amounts of time and distance, due to local patterns of topography and development. We present a method to assess these rates and the evolution of EAE this century for individual municipalities, by integrating exposure computed at various water heights using lidar and census data with distributions of extreme storm events and sea level rise. We apply these techniques to a number of coastal U.S. municipalities, and depending on the carbon emissions choices society makes in the coming decades, high exposure growth rates that are exceptionally rare today (such as in Atlantic City) could become much more commonplace by the end of this century, potentially experienced by major cities such as Boston, Miami, and Hoboken.

  11. Occupational exposure levels of static magnetic field during routine MRI examination in 3T MR system.

    PubMed

    Yamaguchi-Sekino, Sachiko; Nakai, Toshiharu; Imai, Shinya; Izawa, Shuhei; Okuno, Tsutomu

    2014-01-01

    Occupational exposure to the high static magnetic fields (SMFs) during magnetic resonance imaging (MRI) examinations raises concerns of adverse health effects. In this study, personal exposure monitoring of the magnetic fields during routine examinations in two 3 T MRI systems was carried out. A three-axis Hall magnetometer was attached to a subject's chest during monitoring. Data acquisition started every time the subject entered the scanner room and ended when the subject exited the room. Four radiologic technologists from two different institutes participated in this study. The maximum exposed field ranged from 0 to 1250 mT and the average peak magnetic field (B) was 428 ± 231 mT (mean ± standard deviation (SD): number of samples (N) = 103). Then, the relationship between exposure levels and work duties was analyzed. The MRI examination of the head or neck showed the highest average peak B among four work categories. These results provide information of real exposure levels for 3 T MRI system operators and can also improve the current practical training advice for preventing extra occupational field exposure.

  12. Trauma exposure in elementary school children: Description of screening procedures, level of exposure, and posttraumatic stress symptoms.

    PubMed

    Gonzalez, Araceli; Monzon, Nicholas; Solis, Diana; Jaycox, Lisa; Langley, Audra K

    2016-03-01

    Traumatic childhood events can have a significant impact on overall child functioning. Early identification and intervention could offer significant benefits for children's mental health and educational trajectories, but how to effectively identify young children is a challenge. In this paper, we describe screening for exposure to traumatic events and associated symptoms of posttraumatic stress, and examine differences by child gender and grade level. A total of 402 elementary school children in grades 1-5 participated across four elementary schools. We describe modified administration procedures of screening instruments for these young children. Children who endorsed exposure to one or more traumatic events were individually assessed for posttraumatic stress symptom severity. Thirty-four percent (n=138) of children screened experienced one or more traumatic events, and 75.4% of those exposed to at least one traumatic event endorsed moderate levels or higher of posttraumatic stress symptoms. Internal consistency of the symptom self-report instrument was adequate for children of all grade levels. Posttraumatic stress symptom severity increased for children exposed to more types of events. No gender/grade differences were found in symptom severity. Findings suggest that young children are impacted by traumatic events in relatively high numbers, that they can reliably report their posttraumatic stress symptoms, and that a large portion of those exposed to trauma experience significant distress. These results highlight the importance of early screening and identification of these children to curtail potential risk for future academic, social, and psychological maladjustment.

  13. Trauma exposure in elementary school children: Description of screening procedures, level of exposure, and posttraumatic stress symptoms

    PubMed Central

    Gonzalez, Araceli; Monzon, Nicholas; Solis, Diana; Jaycox, Lisa; Langley, Audra K.

    2016-01-01

    Traumatic childhood events can have a significant impact on overall child functioning. Early identification and intervention could offer significant benefits for children’s mental health and educational trajectories, but how to effectively identify young children is a challenge. In this paper, we describe screening for exposure to traumatic events and associated symptoms of posttraumatic stress, and examine differences by child gender and grade level. A total of 402 elementary school children in grades 1-5 participated across four elementary schools. We describe modified administration procedures of screening instruments for these young children. Children who endorsed exposure to one or more traumatic events were individually assessed for posttraumatic stress symptom severity. Thirty-four percent (n=138) of children screened experienced one or more traumatic events, and 75.4% of those exposed to at least one traumatic event endorsed moderate levels or higher of posttraumatic stress symptoms. Internal consistency of the symptom self-report instrument was adequate for children of all grade levels. Posttraumatic stress symptom severity increased for children exposed to more types of events. No gender/grade differences were found in symptom severity. Findings suggest that young children are impacted by traumatic events in relatively high numbers, that they can reliably report their posttraumatic stress symptoms, and that a large portion of those exposed to trauma experience significant distress. These results highlight the importance of early screening and identification of these children to curtail potential risk for future academic, social, and psychological maladjustment. PMID:27721907

  14. Testing surgical gowns for the "anticipated level of exposure".

    PubMed

    Belkin, N L

    2000-04-01

    Although the use of the surgeon's gown dates back to the turn of the century, the need for it to be made of a liquid-repellent material was disclosed only in 1952. Because of the relatively poor performance of the products that were introduced early on, the entire textile industry--makers of nonwoven disposable and woven reusable materials alike--was challenged to develop a test method to demonstrate a fabric's capability "under usual conditions of use." A cooperative attempt to do that was abandoned in 1983. With the emergence of HIV, the need to protect the wearer became the gown's priority. However, because there was no standard test method, the manufacturers used any of an array of tests to promote a product's suitability for use under what the Occupational Safety and Health Administration describes as the "level of exposure anticipated." Now, a standard test method has been adopted that describes the results on a pass/fail basis. However, the literature indicates that gowns made of materials that have passed this test have failed "under usual conditions of use." Nevertheless, the Food and Drug Administration is permitting manufacturers to mislead the surgical community by describing products as being "impervious" or "liquid proof."

  15. High temperature liquid level sensor

    DOEpatents

    Tokarz, Richard D.

    1983-01-01

    A length of metal sheathed metal oxide cable is perforated to permit liquid access to the insulation about a pair of conductors spaced close to one another. Changes in resistance across the conductors will be a function of liquid level, since the wetted insulation will have greater electrical conductivity than that of the dry insulation above the liquid elevation.

  16. MIXED MODELS ANALYSIS OR URBANIZATION LEVEL ON CHLORPYRIFOS EXPOSURE

    EPA Science Inventory

    The National Human Exposure Assessment Survey (NHEXAS) pilot studies were conducted from 1995 through 1997 to examine human population exposure to a wide range of environmental contaminants. In one of the studies, NHEXAS-Maryland, a longitudinal design was used to repeatedly m...

  17. MIXED MODELS ANALYSIS OR URBANIZATION LEVEL ON CHLORPYRIFOS EXPOSURE

    EPA Science Inventory

    The National Human Exposure Assessment Survey (NHEXAS) pilot studies were conducted from 1995 through 1997 to examine human population exposure to a wide range of environmental contaminants. In one of the studies, NHEXAS-Maryland, a longitudinal design was used to repeatedly m...

  18. Deployment-Associated Exposure Surveillance with High-Resolution Metabolomics

    PubMed Central

    Walker, Douglas I.; Mallon, Timothy; Hopke, Philip K.; Uppal, Karan; Go, Young-Mi; Rohrbeck, Patricia; Pennell, Kurt D.; Jones, Dean P.

    2016-01-01

    Objective Assess the suitability of high-resolution metabolomics (HRM) for measure of internal exposure and effect biomarkers from deployment related environmental hazards. Methods HRM provides extensive coverage of metabolism and data relevant to a broad spectrum of environmental exposures. This review briefly describes the analytic platform, workflow and recent applications of HRM as a prototype environmental exposure surveillance system. Results Building upon techniques available for contemporary occupational medicine and exposure sciences, HRM methods are able to integrate external exposures, internal body burden of environmental agents and relevant biological responses with health outcomes. Conclusions Systematic analysis of existing Department of Defense Serum Repository samples will provide a high-quality cross-sectional reference dataset for deployment-associated exposures while at the same time establishing a foundation for precision medicine. PMID:27501099

  19. An assessment of exposure to glutaraldehyde in hospitals: typical exposure levels and recommended control measures.

    PubMed Central

    Leinster, P; Baum, J M; Baxter, P J

    1993-01-01

    An assessment of exposure to glutaraldehyde in cold sterilisation and x ray development processes was undertaken in 14 locations at six hospitals in south east England. The results obtained indicate that routine exposures of hospital workers to airborne concentrations of the compound are within the current United Kingdom occupational exposure limit of 0.7 mg m-3. There was the potential for skin contact in many of the activities observed and alternative sterilisation and disinfection procedures would have been more appropriate in some situations. Recommendations are made on reducing exposures as the current occupational exposure limit for this compound may not be appropriate. PMID:8435342

  20. Exposure levels of farmers and veterinarians to particulate matter and gases during operational tasks in pig-fattening houses.

    PubMed

    Van Ransbeeck, Nele; Van Langenhove, Herman; Michiels, Annelies; Sonck, Bart; Demeyer, Peter

    2014-01-01

    The main objective of the study was to assess particulate matter (PM) exposure levels for both the farmer and the veterinarian during different operational tasks in pig-fattening houses, and to estimate their exposure levels on a daily working basis (time-weighted average (TWA)). The measured PM fractions were: inhalable and respirable PM, PM10, PM2.5 and PM1. The effects of pig age, pen floor type (conventional or low emission surface) and cleaning of the pens on the personal PM exposure were also investigated. Indoor concentrations of NH3, CH4, and CO2 were additionally measured during some operational tasks. The results showed that personal exposure levels can become extremely high during some operational tasks performed by the farmer or veterinarian. The highest concentration levels were observed during feed shovelling and blood sampling, the lowest during the weighing of the pigs. For the farmer, the estimated TWA exposure levels of inhalable and respirable PM were 6.0 and 0.29 mg m(-3), respectively. These exposure levels for the veterinarian were, respectively, 10.6 and 0.74 mg m(-3). The PM concentration levels were mainly determined by the performed operational tasks. There was no significant effect of pig age, pen floor type, nor cleaning of the pens on the personal exposure levels.

  1. High-Level Connectionist Models

    DTIC Science & Technology

    1990-04-01

    Freeman, 1987) and on the mathematical level ( Derrida & Meir, 1988; Huberman & Hogg, 1987; Kurten, 1987). It is time that this link be further...Wesley. Derrida B. & Meir, R. (198sL80moac behavior of a layered neural network. Phys. Rev. A, 38. Elman, J. L. (1988). Findi4 Structure in Time. Report...and Huberman, 1983; Kurten and Clark. 1986; Babcock and Westervelt, 1987; Derrida and Meir, 1988; Riedal et al., 1988; Sompolin- sky et al., 1988

  2. Lead Levels in Landfill Areas and Childhood Exposure: An Integrative Review.

    PubMed

    Kim, M Angela; Williams, Kimberly A

    2017-01-01

    Landfills are high-risk areas for environmental lead exposure for children living in poverty stricken areas in many countries. This review examines landfills and lead toxicity in children. The review discusses the effects of lead toxicity, provides evidenced based recommendations to reduce lead exposure, and identify gaps in the evidence. A database search was conducted of articles in English from 1985 to 2014. Ten articles met the inclusion criteria. The Whittemore and Knafl framework and the John Hopkins Research Evidence Appraisal Tool(©) were used for reviewing the data. Elevated blood lead levels (BLLs) of children living near landfills were related to increased soil lead levels. Toxic effects of lead included adverse outcomes such as encephalopathy or death for children. Different approaches to decrease lead level include environmental surveillance, BLL screening, and soil abatement which are costly. Increased BLL through environmental exposure is connected with poor health outcomes and death among children. Evidence-based prevention included monitoring and screening and costly soil abatement. It is recommended that future studies focus on community education for exposure avoidance for children living near landfill areas. © 2016 Wiley Periodicals, Inc.

  3. 1-Hydroxypyrene Levels in Blood Samples of Rats After Exposure to Generator Fumes

    PubMed Central

    Ifegwu, Clinton; Igwo-Ezikpe, Miriam N.; Anyakora, Chimezie; Osuntoki, Akinniyi; Oseni, Kafayat A.; Alao, Eragbae O.

    2013-01-01

    Polynuclear Aromatic Hydrocarbons (PAHs) are a major component of fuel generator fumes. Carcinogenicity of these compounds has long been established. In this study, 37 Swiss albino rats were exposed to generator fumes at varied distances for 8 hours per day for a period of 42 days and the level of 1-hydroxypyrene in their blood was evaluated. This study also tried to correlate the level of blood 1-hyroxypyrene with the distance from the source of pollution. Plasma was collected by centrifuging the whole blood sample followed by complete hydrolysis of the conjugated 1-hydroxypyrene glucuronide to yield the analyte of interest, 1-hydroxypyrene, which was achieved using beta glucuronidase. High performance liquid chromatography (HPLC) with UV detector was used to determine the 1-hydroxypyrene concentrations in the blood samples. The mobile phase was water:methanol (12:88 v/v) isocratic run at the flow rate of 1.2 mL/min with CI8 stationary phase at 250 nm. After 42 days of exposure, blood concentration level of 1-hydroxypyrene ranged from 34 μg/mL to 26.29 μg/mL depending on the distance from source of exposure. The control group had no 1-hydroxypyrene in their blood. After the period of exposure, percentage of death correlated with the distance from the source of exposure. Percentage of death ranged from 56% to zero depending on the proximity to source of pollution. PMID:24179393

  4. 1-hydroxypyrene levels in blood samples of rats after exposure to generator fumes.

    PubMed

    Ifegwu, Clinton; Igwo-Ezikpe, Miriam N; Anyakora, Chimezie; Osuntoki, Akinniyi; Oseni, Kafayat A; Alao, Eragbae O

    2013-01-01

    Polynuclear Aromatic Hydrocarbons (PAHs) are a major component of fuel generator fumes. Carcinogenicity of these compounds has long been established. In this study, 37 Swiss albino rats were exposed to generator fumes at varied distances for 8 hours per day for a period of 42 days and the level of 1-hydroxypyrene in their blood was evaluated. This study also tried to correlate the level of blood 1-hyroxypyrene with the distance from the source of pollution. Plasma was collected by centrifuging the whole blood sample followed by complete hydrolysis of the conjugated 1-hydroxypyrene glucuronide to yield the analyte of interest, 1-hydroxypyrene, which was achieved using beta glucuronidase. High performance liquid chromatography (HPLC) with UV detector was used to determine the 1-hydroxypyrene concentrations in the blood samples. The mobile phase was water:methanol (12:88 v/v) isocratic run at the flow rate of 1.2 mL/min with CI8 stationary phase at 250 nm. After 42 days of exposure, blood concentration level of 1-hydroxypyrene ranged from 34 μg/mL to 26.29 μg/mL depending on the distance from source of exposure. The control group had no 1-hydroxypyrene in their blood. After the period of exposure, percentage of death correlated with the distance from the source of exposure. Percentage of death ranged from 56% to zero depending on the proximity to source of pollution.

  5. [Investigation of air pollution in a shopping center and employees' personal exposure level].

    PubMed

    Manabe, Ryuji; Kunugita, Naoki; Katoh, Takahiko; Kuroda, Yoshiki; Akiyama, Yukio; Yamano, Yuko; Uchiyama, Iwao; Arashidani, Keiichi

    2008-01-01

    To investigate the concentrations of chemicals found inside a shopping center (SC), we investigated the condition of air pollution in a SC and the personal exposure level of SC employees. The survey was performed in June 2006 in Kyushu. The chemicals studied were volatile organic compounds (VOCs) and aldehydes. The chemicals were collected by a personal passive sampler. Thirty-one VOCs and aldehydes were detected inside the SC. The results showed that the concentrations of all the chemicals detected in indoor air were less than those specified in the indoor air quality guideline of Ministry of Health, Labor and Welfare, Japan. The chemical concentrations in the SC decreased in the order of food corner > electric, clothing corner > outdoor and were clearly higher than those outdoors. Therefore, it is thought that the source of chemicals is indoors. The high indoor concentration of 2-ethyl-1-hexanol may be due to diffusion from the walls and floors. In addition, it is suggested that the personal exposure condition of the employees reflected the indoor concentration of each sales floor. The exposure level to formaldehyde was higher at nonworking time than at working time, suggesting that a larger exposure source exists in the place of residence than in the work place. We found that indoor air quality in SC is maintained at good levels. This might be because of the Japanese strict regulations that require administrations of large-scale buildings to provide adequate ventilation and perform regular measurement of indoor air quality.

  6. Existential Anxiety Among Adolescents Exposed to Disaster: Linkages Among Level of Exposure, PTSD, and Depression Symptoms.

    PubMed

    Weems, Carl F; Russell, Justin D; Neill, Erin L; Berman, Steven L; Scott, Brandon G

    2016-10-01

    Exposure to natural disasters can be highly traumatic and have a detrimental effect on youth mental health by threatening the satisfaction of basic human needs and goals. Recent research in adults suggests that exposure to disasters may exacerbate existential anxiety about the meaning of life. The current study expands this investigation to adolescents, who may be particularly vulnerable to the negative effects of disaster. Data came from 325 adolescents (mean age = 15.05 years, SD = 1.05) residing in the Greater New Orleans area who were exposed to Hurricanes Katrina and/or Gustav. Existential anxiety concerns were highly prevalent in the sample and were associated with elevated levels of posttraumatic stress disorder (R(2) = .09) and depression symptoms (R(2) = .13). Consistent with theoretical predictions, disaster exposure levels moderated the association between facets of existential anxiety and mental health symptoms. Findings highlight the salience of existential concerns in disaster exposed youth, and provide evidence that exposure to traumatic stress may strengthen their association with mental health problems. Copyright © 2016 International Society for Traumatic Stress Studies.

  7. Aflatoxin levels and exposure assessment of Spanish infant cereals.

    PubMed

    Hernández-Martínez, Raquel; Navarro-Blasco, Iñigo

    2010-01-01

    Aflatoxins (AFB1, AFB2, AFG1 and AFG2) are immunosuppressant, mutagenic, teratogenic and carcinogenic agents with a widespread presence in foodstuffs. Since human exposure to aflatoxins occurs primarily by contaminated food intake, and given the greater susceptibility of infants to their adverse effects, the quantification of these mycotoxins in infant food based on cereals is of relevance. Aflatoxin levels were determined in 91 Spanish infant cereals classified in terms of non- and organically produced and several types from 10 different manufacturers, using a extraction procedure followed by inmunoaffinity column clean-up step and HPLC with fluorescence detection (FLD) and post-column derivatisation (Kobra Cell system). Daily aflatoxin intake was also assessed. Preliminary analysis showed a valuable incidence of detected infant cereal samples at an upper concentration level than the detection limit for total aflatoxin (66%), corresponding to a 46, 40, 34 and 11% for AFB1, AFB2, AFG1 and AFG2, respectively. Lower aflatoxin values (median, Q1, Q3) in conventional infant cereal (n = 74, AFB1: levels. Gluten-free and cereals with dehydrated fruits had an intermediate level and milk- or honey-based cereals and multi-cereals contained the lowest levels. With the exception of the non-compliant cocoa-based organic formulation

  8. Second-hand smoke exposure and blood lead levels in U.S. children.

    PubMed

    Mannino, David M; Albalak, Rachel; Grosse, Scott; Repace, James

    2003-11-01

    Lead is a component of tobacco and tobacco smoke, and smokers have higher blood lead levels than do nonsmokers. We examined the relation between second-hand smoke exposure and blood lead levels in a nationally representative sample of 5592 U.S. children, age 4-16 years, who participated in the Third National Health and Nutrition Examination Survey (1988-1994). Linear and logistic regression modeling was used to adjust for known covariates. Geometric mean blood lead levels were 1.5 mug/dL, 1.9 mug/dL, and 2.6 mug/dL for children with low, intermediate, and high cotinine levels, respectively. The adjusted linear regression model showed that geometric mean blood lead levels were 38% higher (95% confidence interval [CI] = 25-52%) in children with high cotinine levels compared with children who had low cotinine levels. The logistic regression models showed that children with high cotinine levels were more likely to have blood lead levels >/=10 mug/dL than were children with low cotinine levels (odds ratio [OR] = 4.4; CI = 1.9-10.5). Second-hand smoke could be associated with increased blood lead levels in U.S. children aged 4-16 years.

  9. Elevated lead levels from e-waste exposure are linked to decreased olfactory memory in children.

    PubMed

    Zhang, Bo; Huo, Xia; Xu, Long; Cheng, Zhiheng; Cong, Xiaowei; Lu, Xueling; Xu, Xijin

    2017-08-09

    Lead (Pb) is a developmental neurotoxicant and can cause abnormal development of the nervous system in children. Hence, the aim of this study was to investigate the effect of Pb exposure on child olfactory memory by correlating the blood Pb levels of children in Guiyu with olfactory memory tests. We recruited 61 preschool children, 4- to 7-years of age, from Guiyu and 57 children from Haojiang. The mean blood Pb level of Guiyu children was 9.40 μg/dL, significantly higher than the 5.04 μg/dL mean blood Pb level of Haojiang children. In addition, approximately 23% of Guiyu children had blood Pb levels exceeding 10.00 μg/dL. The correlation analysis showed that blood Pb levels in children highly correlated with e-waste contact (rs = 0.393). Moreover, the mean concentration of serum BDNF in Guiyu children (35.91 ng/ml) was higher than for Haojiang (28.10 ng/ml) and was positively correlated with blood Pb levels. Both item and source olfactory memory tests at 15 min, 5 h and 24 h after odor exposure showed that scores were lower in Guiyu children indicative of reduced olfactory memory in Guiyu children. Olfactory memory tests scores negatively correlated with blood Pb and serum BDNF levels, but were positively associated with parental education levels. At the same time, scores of both tests on children in the high blood Pb level group (blood Pb levels > 5.00 μg/dL) were lower than those in the low blood Pb level group (blood Pb levels ≤ 5.00 μg/dL), implying that Pb exposure decreases olfactory memory in children. Our findings suggest that Pb exposure in e-waste recycling and dismantling areas could result in an increase in serum BDNF level and a decrease in child olfactory memory, in addition, BDNF might be involved in olfactory memory impairment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Personal exposure to ultrafine particles: Two-level statistical modeling of background exposure and time-activity patterns during three seasons.

    PubMed

    Deffner, Veronika; Küchenhoff, Helmut; Maier, Verena; Pitz, Mike; Cyrys, Josef; Breitner, Susanne; Schneider, Alexandra; Gu, Jianwei; Geruschkat, Uta; Peters, Annette

    2016-01-01

    Personal exposure to air pollution is associated with time- and location-specific factors including indoor and outdoor air pollution, meteorology and time activities. Our investigation aims at the description and identification of factors determining personal exposure to particle number concentration (PNC) in everyday situations. Ten volunteers recorded their personal exposure to PNC and kept an activity diary in three different seasons besides stationary measurements of ambient air pollution and meteorology. Background exposure to PNC was modelled using the most predictive variables. In a second step, the effects of the activities were calculated adjusted for the background exposure. The average personal PNC level was highest in winter and was three times higher than the mean stationary PNC level while staying indoors and two times higher while staying outdoors. Personal indoor PNC levels were significantly increased during the use of candles, cooking and the occurrence of smell of food. High stationary outdoor PNC levels and low dew point temperatures were associated with increased personal outdoor PNC levels. Times spent in public transport were associated with lower personal PNC levels than other times spent in transportation. Personal PNC levels in everyday situations exhibited a large variability because of seasonal, microenvironment-specific and activity-specific influences.

  11. ORGANOPHOSPHATE PESTICIDE EXPOSURES - WHERE ARE THE HIGH RISK CHILDREN?

    EPA Science Inventory

    Methods to identify children at high-risk for organophosphate (OP) pesticide exposure are difficult to develop because biological markers reflect only recent "snapshots" of exposure due to the short half-life of OP compounds (generally about 24 hours). We conducted a series of p...

  12. ORGANOPHOSPHATE PESTICIDE EXPOSURES - WHERE ARE THE HIGH RISK CHILDREN?

    EPA Science Inventory

    Methods to identify children at high-risk for organophosphate (OP) pesticide exposure are difficult to develop because biological markers reflect only recent "snapshots" of exposure due to the short half-life of OP compounds (generally about 24 hours). We conducted a series of p...

  13. Changes of polybrominated diphenyl ether concentrations in ducks with background exposure level and time.

    PubMed

    Liu, Peng-Yan; Chen, Xiao-Ran; Zhao, Ya-Xian; Li, Yuan-Yuan; Qin, Xiao-Fei; Qin, Zhan-Fen

    2015-01-01

    To reveal what degree bioaccumulation of polybrominated diphenyl ethers (PBDEs) depends on exposure time and other factors, we conducted a semi-field experiment for a year (June 2008-June 2009) in a village in an e-waste recycling site in Taizhou, China. Approximately one hundred of juvenile ducks (Anas domestica Linnaeus) were entrusted to a villager. The ducks lived and forged in a PBDE-polluted pond from the late March to the end of November. Fish and mudsnails that were heavily polluted by PBDEs were main food. In cold days (from December to the middle March), the ducks lived in the villager' house, and mainly fed on paddy, which contained lower concentrations of PBDEs than fish and mudsnails. The female ducks were sampled for PBDE analysis every three months. We found that the ∑PBDE concentrations in duck liver, muscle, lung and brain fluctuated greatly with the changes of exposure levels that were determined by the environment and diets, but the ∑PBDE concentrations in fat tissue increased successively with time. Congener analysis demonstrated that the successive increase in the ∑PBDE concentrations with time in fat tissue was due to the successive increase in BDE-209, -183 and -153 concentrations, with large fluctuations of low brominated congeners. The results show that PBDE concentrations in liver, muscle, lung and brain tissues heavily depends on exposure levels rather than exposure time. In fat tissue, by contrast, PBDE concentrations (mainly high brominated congeners) slightly depends on exposure levels but heavily depend on time relative to other tissues, implying that high brominated congeners seem to have longer half-lives than low brominated congeners in fat tissue. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Exposure and preventive measure to reduce high and daily exposure to Bacillus thuringiensis in potted plant production.

    PubMed

    Madsen, Anne Mette; Zervas, Athanasios; Tendal, Kira; Matthiesen, Christoffer B; Koponen, Ismo Kalevi; Hansen, Erik Wind

    2014-07-01

    The bacterium Bacillus thuringiensis (Bt) is the active organism in a variety of commercially available products used worldwide as biopesticides. Bt products are applied in large outdoor areas as well as in indoor environments. Even though it has been sold for decades, not much is known about the occupational exposure to Bt. The aim of this study was to obtain knowledge about the exposure to Bt subspecies israelensis (Bti) in a propagation section in a greenhouse, where Bti is applied hourly by a spray boom, and to test a preventive measure to reduce the exposure to airborne Bti. Furthermore, we wanted to study the exposure during work with potted plants treated earlier with Bti. Exposure to aerosols with Bti was measured repeatedly by personal and stationary samplers before and after the intervention. Bti was identified by polymerase chain reaction in air and soil samples. Personal exposure to inhalable Bti in the propagation section was 3×10(5) cfu m(-3) (median level, n = 22); the personal exposure of people working with plants treated earlier with Bti was 3200 cfu m(-3) (median level, n = 17). The highest single measure was found for the person working with the spray boom (7×10(5) cfu m(-3)) but airborne Bti was present at all sampling stations in the propagation section. Bti constituted a high share of the airborne cultivable bacteria and a smaller share of the soilborne bacteria in the propagation section. In a human cell assay, spiking an aerosol sample with a product with Bti increased the inflammatory potential of an aerosol sample from the greenhouse significantly. Based on the inflammatory potential and the high personal exposure, a cover around the spray boom was built as an attempt to reduce the daily exposure to Bti. The cover reduced the personal exposure to Bti from 3.0×10(5) cfu m(-3) to 1.8×10(4) cfu m(-3). The exposure was thus reduced by a factor 17, which is a considerable reduction. Bti was present in different particle size fractions with

  15. High-Level Data Races

    NASA Technical Reports Server (NTRS)

    Artho, Cyrille; Havelund, Klaus; Biere, Armin; Koga, Dennis (Technical Monitor)

    2003-01-01

    Data races are a common problem in concurrent and multi-threaded programming. They are hard to detect without proper tool support. Despite the successful application of these tools, experience shows that the notion of data race is not powerful enough to capture certain types of inconsistencies occurring in practice. In this paper we investigate data races on a higher abstraction layer. This enables us to detect inconsistent uses of shared variables, even if no classical race condition occurs. For example, a data structure representing a coordinate pair may have to be treated atomically. By lifting the meaning of a data race to a higher level, such problems can now be covered. The paper defines the concepts view and view consistency to give a notation for this novel kind of property. It describes what kinds of errors can be detected with this new definition, and where its limitations are. It also gives a formal guideline for using data structures in a multi-threading environment.

  16. Low-level arsenic exposure: nutritional and dietary predictors in first-grade Uruguayan children

    PubMed Central

    Kordas, Katarzyna; Queirolo, Elena I; Mañay, Nelly; Peregalli, Fabiana; Hsiao, Pao Ying; Lu, Ying; Vahter, Marie

    2016-01-01

    Arsenic exposure in children is a public health concern but is understudied in relation to the predictors, and effects of low-level exposure. We examined the extent and dietary predictors of exposure to inorganic arsenic in 5–8 year old children from Montevideo, Uruguay. Children were recruited at school; 357 were enrolled, 328 collected morning urine samples, and 317 had two 24-hour dietary recalls. Urinary arsenic metabolites, i.e. inorganic arsenic (iAs), methylarsonic acid (MMA), and dimethylarsinic acid (DMA), were measured using high-performance liquid chromatography with hydride generation and inductively coupled plasma mass spectrometry (HPLC-HG-ICP-MS), and the sum concentration (U-As) used for exposure assessment. Proportions of arsenic metabolites (%iAs, %MMA and %DMA) in urine were modelled in OLS regressions as functions of food groups, dietary patterns, nutrient intake, and nutritional status. Exposure to arsenic was low (median U-As: 9.9 µg/L) and household water (water As: median 0.45 µg/L) was not a major contributor to exposure. Children with higher consumption of rice had higher U-As but lower %iAs, %MMA, and higher %DMA. Children with higher meat consumption had lower %iAs and higher %DMA. Higher scores on ”nutrient dense” dietary pattern were related to lower %iAs and %MMA, and higher %DMA. Higher intake of dietary folate was associated with lower %MMA and higher %DMA. Overweight children had lower %MMA and higher %DMA than normal-weight children. In summary, rice was an important predictor of exposure to inorganic arsenic and DMA. Higher meat and folate consumption, diet rich in green leafy and red-orange vegetables and eggs, and higher BMI contributed to higher arsenic methylation capacity. PMID:26828624

  17. Low-level arsenic exposure: Nutritional and dietary predictors in first-grade Uruguayan children.

    PubMed

    Kordas, Katarzyna; Queirolo, Elena I; Mañay, Nelly; Peregalli, Fabiana; Hsiao, Pao Ying; Lu, Ying; Vahter, Marie

    2016-05-01

    Arsenic exposure in children is a public health concern but is understudied in relation to the predictors, and effects of low-level exposure. We examined the extent and dietary predictors of exposure to inorganic arsenic in 5-8 year old children from Montevideo, Uruguay. Children were recruited at school; 357 were enrolled, 328 collected morning urine samples, and 317 had two 24-h dietary recalls. Urinary arsenic metabolites, i.e. inorganic arsenic (iAs), methylarsonic acid (MMA), and dimethylarsinic acid (DMA), were measured using high-performance liquid chromatography with hydride generation and inductively coupled plasma mass spectrometry (HPLC-HG-ICP-MS), and the sum concentration (U-As) used for exposure assessment. Proportions of arsenic metabolites (%iAs, %MMA and %DMA) in urine were modelled in OLS regressions as functions of food groups, dietary patterns, nutrient intake, and nutritional status. Exposure to arsenic was low (median U-As: 9.9µg/L) and household water (water As: median 0.45µg/L) was not a major contributor to exposure. Children with higher consumption of rice had higher U-As but lower %iAs, %MMA, and higher %DMA. Children with higher meat consumption had lower %iAs and higher %DMA. Higher scores on "nutrient dense" dietary pattern were related to lower %iAs and %MMA, and higher %DMA. Higher intake of dietary folate was associated with lower %MMA and higher %DMA. Overweight children had lower %MMA and higher %DMA than normal-weight children. In summary, rice was an important predictor of exposure to inorganic arsenic and DMA. Higher meat and folate consumption, diet rich in green leafy and red-orange vegetables and eggs, and higher BMI contributed to higher arsenic methylation capacity.

  18. The discrepancy between maximum in vitro exposure levels and realistic conservative exposure levels of mobile phones operating at 900/1800 MHz.

    PubMed

    Schmid, Gernot; Kuster, Niels

    2015-02-01

    The objective of this paper is to compare realistic maximum electromagnetic exposure of human tissues generated by mobile phones with electromagnetic exposures applied during in vitro experiments to assess potentially adverse effects of electromagnetic exposure in the radiofrequency range. We reviewed 80 in vitro studies published between 2002 and present that concern possible adverse effects of exposure to mobile phones operating in the 900 and 1800 MHz bands. We found that the highest exposure level averaged over the cell medium that includes evaluated cells (monolayer or suspension) used in 51 of the 80 studies corresponds to 2 W/kg or less, a level below the limit defined for the general public. That does not take into account any exposure non-uniformity. For comparison, we estimated, by numerical means using dipoles and a commercial mobile phone model, the maximum conservative exposure of superficial tissues from sources operated in the 900 and 1800 MHz bands. The analysis demonstrated that exposure of skin, blood, and muscle tissues may well exceed 40 W/kg at the cell level. Consequently, in vitro studies reporting minimal or no effects in response to maximum exposure of 2 W/kg or less averaged over the cell media, which includes the cells, may be of only limited value for analyzing risk from realistic mobile phone exposure. We, therefore, recommend future in vitro experiments use specific absorption rate levels that reflect maximum exposures and that additional temperature control groups be included to account for sample heating. © 2015 Wiley Periodicals, Inc.

  19. Effects of long term low- and high-dose sodium arsenite exposure in human transitional cells

    PubMed Central

    He, Jianming; Wang, Feng; Luo, Fen; Chen, Xuedan; Liang, Xi; Jiang, Wenbin; Huang, Zhizhong; Lei, Jiafan; Shan, Fabo; Xu, Xueqing

    2017-01-01

    Epidemiological studies have revealed the association between increased risk of bladder cancer and chronic arsenic exposure. Here, we explored biological effects of arsenic in T24. Microarray analysis was applied to analyze mRNA in T24 following 0, 2 or 5 μM sodium arsenite (As) exposure for 72 hours. Long term (up to 140 days) low-dose (200 nM) and high-dose (1,000 nM) As decreased E-cadherin protein level through different mechanisms because the mRNA levels of E-cadherin increased following low-dose As exposure but decreased following high-dose As exposure. Long term As increased the protein levels of N-cadherin, vimentin, β-catenin, and slug. Low-dose As exposure resulted in a change in the morphology of T24 cells from an epithelial to a mesenchymal-like appearance. Knockdown of E-cadherin increased the protein levels of N-cadherin, vimentin, β-catenin, and slug. Cell proliferation and growth of T24 with or without As exposure for 100 days were assayed using EdU and WST, respectively. Low-dose As exposure increased cell proliferation and growth while high-dose As exposure decreased both. Long term As activated p53 on account of increasing protein levels of p53, p-p53 (Ser15), and mRNA levels of p21. These demonstrate that arsenic exposure exerts multiple effects. Long term low- or high-dose arsenic induces epithelial-mesenchymal transition, likely via downregulation of E-cadherin, activates p53, and differently affects cell proliferation/growth. PMID:28337271

  20. Low-level arsenic exposure in drinking water and bladder cancer: a review and meta-analysis.

    PubMed

    Mink, Pamela J; Alexander, Dominik D; Barraj, Leila M; Kelsh, Michael A; Tsuji, Joyce S

    2008-12-01

    Although exposure to high levels of arsenic in drinking water is associated with excess cancer risk (e.g., skin, bladder, and lung), lower exposures (e.g., <100-200 microg/L) generally are not. Lack of significant associations at lower exposures may be attributed to methodologic issues (e.g., inadequate statistical power, exposure misclassification), or to differences in the dose-response relationship at high versus low exposures. The objectives of this review and meta-analysis were to evaluate associations, examine heterogeneity across studies, address study design and sample size issues, and improve the precision of estimates. Eight studies of bladder cancer and low-level arsenic exposure met our inclusion criteria. Meta-analyses of never smokers produced summary relative risk estimates (SRREs) below 1.0 (highest versus lowest exposure). The SRRE for never and ever smokers combined was elevated slightly, but not significantly (1.11; 95% CI: 0.95-1.30). The SRRE was somewhat elevated among ever smokers (1.24; 95% CI: 0.99-1.56), and statistical significance was observed in some subgroup analyses; however, heterogeneity across studies was commonly present. Although uncertainties remain, low-level arsenic exposure alone did not appear to be a significant independent risk factor for bladder cancer. More studies with detailed smoking history will help resolve whether smoking is an effect modifier.

  1. Storage phosphor radiography of wrist fractures: a subjective comparison of image quality at varying exposure levels.

    PubMed

    Peer, Regina; Lanser, Anton; Giacomuzzi, Salvatore M; Pechlaner, Sigurd; Künzel, Heinz; Bodner, Gerd; Gaber, O; Jaschke, Werner; Peer, Siegfried

    2002-06-01

    Image quality of storage phosphor radiographs acquired at different exposure levels was compared to define the minimal radiation dose needed to achieve images which allow for reliable detection of wrist fractures. In a study on 33 fractured anatomical wrist specimens image quality of storage phosphor radiographs was assessed on a diagnostic PACS workstation by three observers. Images were acquired at exposure levels corresponding to a speed classes 100, 200, 400 and 800. Cortical bone surface, trabecular bone, soft tissues and fracture delineation were judged on a subjective basis. Image quality was rated according to a standard protocol and statistical evaluation was performed based on an analysis of variance (ANOVA). Images at a dose reduction of 37% were rated sufficient quality without loss in diagnostic accuracy. Sufficient trabecular and cortical bone presentation was still achieved at a dose reduction of 62%. The latter images, however, were considered unacceptable for fracture detection. To achieve high-quality storage phosphor radiographs, which allow for a reliable evaluation of wrist fractures, a minimum exposure dose equivalent to a speed class of 200 is needed. For general-purpose skeletal radiography, however, a dose reduction of up to 62% can be achieved. A choice of exposure settings according to the clinical situation (ALARA principle) is recommended to achieve possible dose reductions.

  2. Determinants of fine particle (PM 2.5) personal exposure levels in transport microenvironments, London, UK

    NASA Astrophysics Data System (ADS)

    Adams, H. S.; Nieuwenhuijsen, M. J.; Colvile, R. N.

    A series of field studies were carried out in London, UK, during 1999-2000 in which over 400 fine particle (PM 2.5) personal exposure level measurements were taken for journeys in bicycle, bus, car and underground rail transport microenvironments. This was the first comprehensive PM 2.5 personal exposure study of transport users. Both a fixed-route multi-transport mode study and a study of cyclists' commuter journeys were undertaken. Subsequent to these field studies regression modelling of possible influencing factors of these exposure levels was carried out. Meteorological variables, traffic density, mode and route were considered; the relationships of personal exposure levels with fixed site monitor (FSM) concentrations, and of the FSM concentrations with the potential predictor variables, were also investigated. This analysis of the determinants of transport user exposure to PM 2.5 in London, UK, showed that wind speed had a significant influence on personal exposure levels, though explained only up to 20% of the variability of road transport user exposure levels. The occurrence of higher wind speeds was strongly associated with a decrease in personal exposure levels; a 1.5-2.0 fold difference in exposure level concentrations was estimated between the 10th and 90th percentiles of wind speed. Route was a significant factor, whilst mode was not a significant factor in the street microenvironment (between bicycle, bus and car modes); models incorporating route and mode, as well as wind speed, explained approximately 35% of the variability in PM 2.5 exposure levels. Personal exposure levels were reasonably correlated with urban background FSM concentrations, for fixed-route road mode (bicycle, bus and car) exposure level concentrations, r=0.27 ( p<0.01) and for commuter cyclists' exposure level concentrations r=0.58 ( p<0.01).

  3. Changes to colour vision on exposure to high altitude.

    PubMed

    Davies, A J; Morris, D S; Kalson, N S; Wright, A D; Imray, C H E; Hogg, C R

    2011-03-01

    Several studies have shown deterioration in colour vision at altitudes above 3,000m. These studies have been conducted in photopic (bright daylight) conditions, whereas many military operations take place in mesopic (dim light) conditions. Data suggests that the tritan colour vision axis (blue cones, TA) are more susceptible to hypoxic insult than protan axis (red cones, PA). The objective of this study was to examine colour vision at high altitude, in mesopic conditions, and using a novel method of assessment to discriminate between the tritan and protan axis. We examined 42 eyes (21 subjects, mean age 44, range 22-71), at sea level and within 12-36 hours of exposure to 3300m. This was done in a darkened room, with refractive error correction. Colour vision was studied using ChromaTest, a software programme that analyzes colour contrast threshold (CCT) of both TA and PA. We planned to repeat CCT measurement at 4,392m, but technology failure prevented this. Non-parametric paired data was examined using the Wilcoxon signed rank test. There was found to be no change to either the PA (p = 0.409) or the TA (p = 0.871) upon ascent. Within the PA 16 eyes had a lower CCT at high altitude, whilst 26 were higher. In the TA 20 eyes had a lower CCT and 22 were higher. At sea level, mean CCT for PA was 4.21 (SD 2.29) TA was 7.06 (SD 1.77). At 3,300m mean CCT for PA was 4.36 (SD 2.86) and TA was 6.93 (SD 2.39). This experiment revealed no changes to colour vision with exposure to 3,300m. This may be below the threshold altitude for cone dysfunction, alternatively colour vision deterioration may be less significant in mesopic conditions.

  4. Effects of Low-Level Blast Exposure on the Nervous System: Is There Really a Controversy?

    PubMed Central

    Elder, Gregory A.; Stone, James R.; Ahlers, Stephen T.

    2014-01-01

    High-pressure blast waves can cause extensive CNS injury in human beings. However, in combat settings, such as Iraq and Afghanistan, lower level exposures associated with mild traumatic brain injury (mTBI) or subclinical exposure have been much more common. Yet controversy exists concerning what traits can be attributed to low-level blast, in large part due to the difficulty of distinguishing blast-related mTBI from post-traumatic stress disorder (PTSD). We describe how TBI is defined in human beings and the problems posed in using current definitions to recognize blast-related mTBI. We next consider the problem of applying definitions of human mTBI to animal models, in particular that TBI severity in human beings is defined in relation to alteration of consciousness at the time of injury, which typically cannot be assessed in animals. However, based on outcome assessments, a condition of “low-level” blast exposure can be defined in animals that likely approximates human mTBI or subclinical exposure. We review blast injury modeling in animals noting that inconsistencies in experimental approach have contributed to uncertainty over the effects of low-level blast. Yet, animal studies show that low-level blast pressure waves are transmitted to the brain. In brain, low-level blast exposures cause behavioral, biochemical, pathological, and physiological effects on the nervous system including the induction of PTSD-related behavioral traits in the absence of a psychological stressor. We review the relationship of blast exposure to chronic neurodegenerative diseases noting the paradoxical lowering of Abeta by blast, which along with other observations suggest that blast-related TBI is pathophysiologically distinct from non-blast TBI. Human neuroimaging studies show that blast-related mTBI is associated with a variety of chronic effects that are unlikely to be explained by co-morbid PTSD. We conclude that abundant evidence supports low-level blast as having long

  5. Polychlorinated biphenyl sources, environmental levels, and exposures in school buildings

    EPA Science Inventory

    Background: Building materials and components containing polychlorinated biphenyls (PCBs) were used in some U.S. school buildings until the late 1970s and may be present today. There is limited information on source factors and occupant exposures. Methods: Analysis of PCBs in mat...

  6. Polychlorinated biphenyl sources, environmental levels, and exposures in school buildings

    EPA Science Inventory

    Background: Building materials and components containing polychlorinated biphenyls (PCBs) were used in some U.S. school buildings until the late 1970s and may be present today. There is limited information on source factors and occupant exposures. Methods: Analysis of PCBs in mat...

  7. Exposure time optimization for highly dynamic star trackers.

    PubMed

    Wei, Xinguo; Tan, Wei; Li, Jian; Zhang, Guangjun

    2014-03-11

    Under highly dynamic conditions, the star-spots on the image sensor of a star tracker move across many pixels during the exposure time, which will reduce star detection sensitivity and increase star location errors. However, this kind of effect can be compensated well by setting an appropriate exposure time. This paper focuses on how exposure time affects the star tracker under highly dynamic conditions and how to determine the most appropriate exposure time for this case. Firstly, the effect of exposure time on star detection sensitivity is analyzed by establishing the dynamic star-spot imaging model. Then the star location error is deduced based on the error analysis of the sub-pixel centroiding algorithm. Combining these analyses, the effect of exposure time on attitude accuracy is finally determined. Some simulations are carried out to validate these effects, and the results show that there are different optimal exposure times for different angular velocities of a star tracker with a given configuration. In addition, the results of night sky experiments using a real star tracker agree with the simulation results. The summarized regularities in this paper should prove helpful in the system design and dynamic performance evaluation of the highly dynamic star trackers.

  8. Exposure Time Optimization for Highly Dynamic Star Trackers

    PubMed Central

    Wei, Xinguo; Tan, Wei; Li, Jian; Zhang, Guangjun

    2014-01-01

    Under highly dynamic conditions, the star-spots on the image sensor of a star tracker move across many pixels during the exposure time, which will reduce star detection sensitivity and increase star location errors. However, this kind of effect can be compensated well by setting an appropriate exposure time. This paper focuses on how exposure time affects the star tracker under highly dynamic conditions and how to determine the most appropriate exposure time for this case. Firstly, the effect of exposure time on star detection sensitivity is analyzed by establishing the dynamic star-spot imaging model. Then the star location error is deduced based on the error analysis of the sub-pixel centroiding algorithm. Combining these analyses, the effect of exposure time on attitude accuracy is finally determined. Some simulations are carried out to validate these effects, and the results show that there are different optimal exposure times for different angular velocities of a star tracker with a given configuration. In addition, the results of night sky experiments using a real star tracker agree with the simulation results. The summarized regularities in this paper should prove helpful in the system design and dynamic performance evaluation of the highly dynamic star trackers. PMID:24618776

  9. The Association between Exposure to Environmental Bisphenol A and Gonadotropic Hormone Levels among Men

    PubMed Central

    Chen, Jianping; Shi, Huijuan; Zhu, Jiang; Liu, Xiaoqin; Wang, Jian; Miao, Maohua; Yuan, Wei

    2017-01-01

    Bisphenol A (BPA) is an extensively used chemical with endocrine disrupting properties. Although animal and in vivo studies have suggested possible effects of BPA on levels of gonadotropic hormones, human studies are limited and inconclusive. The study examined whether environmental BPA exposure was associated with gonadotropic hormones levels in men. A total of 560 men aged 18–55 years were recruited from Sandu County, Guizhou Province, China. We collected urine samples for measurement of BPA, and blood samples for measurement of reproductive hormones. We examined serum levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), and total testosterone (T). Relative risk (RR) was obtained by log-binominal regression to explore the association between urinary BPA level and hormone levels. BPA was detected in 70.4% of urine samples, with a geometric mean of 0.50 μg/gCr. Men with detectable levels of BPA had a 1.52-fold increased risk of having a high LH level (>75th percentile) when compared with men with undetectable levels of BPA, after adjustment for potential confounders (95% confidence interval (CI): 1.04–2.21). The association persisted and slightly intensified among current smokers (adjusted RR (aRR) = 1.76, 95%CI: 1.05–2.95), while it weakened among non-smokers (aRR = 1.17, 95%CI: 0.69–1.96). Urinary BPA level was associated with an increased FSH level among smokers (aRR = 1.64, 95%CI: 1.01–2.67). Urinary BPA level was inversely associated with total T level among males with body max index (BMI) ≥25 kg/m2 although this association was of borderline significance (aRR = 0.52, 95%CI: 0.26–1.05). In conclusion, environmental exposure to BPA was associated with increased serum levels of LH and FSH in male smokers, along with decreased serum levels of total T in men with BMI≥25 kg/m2. These findings suggest that the effects of environmental BPA exposure on hormone levels might be modified by smoking and BMI. PMID:28085949

  10. Hair mercury levels in pregnant women in Mahshahr, Iran: fish consumption as a determinant of exposure.

    PubMed

    Salehi, Zohreh; Esmaili-Sari, Abbas

    2010-09-15

    MeHg is a well-documented neurotoxicant even at low levels of exposure. Developing brain, in particular, is vulnerable to that. Through bioaccumulating to differing degrees in various fish species, it can have serious adverse effects on the development and functioning of the human central nervous system, especially during prenatal exposure. Therefore, the purpose of this study was to investigate mercury concentration in hair samples of pregnant women living in Mahshahr located in Khuzestan province, Iran. It assessed the association between fish consumption and specific characteristics that can influence exposure. From April to June 2008, 149 pregnant women were invited to participate in this study. An interview administered questionnaire was used to collect information about age, body weight, height, fish (fresh, canned and shrimp) consumption, pregnancy stage, residence duration, education level, family income and number of dental amalgam fillings. The obtained results showed that the geometric mean and range for hair total Hg concentration was 3.52 microg/g (0.44-53.56 microg/g). About 5.4% of mothers had hair total Hg levels in excess of 10 microg/g. Maternal hair mercury level was less than threshold level of WHO (5 microg/g). As expected, there was a clear increase in hair Hg with reported fresh marine fish consumption (p=0.04). The highest mean for hair mercury level in a group who consumed fish several times per week, was 4.93 microg/g. Moreover, a significant effect of age and residential time on Hg concentration in the hair of the women was found. Pregnant women in Mahshahr consumed large amounts of fish; consequently, most of their offspring were prenatally exposed to moderately high levels of mercury. The results found suggest that pregnant women should decrease their fish consumption.

  11. Impact of high electromagnetic field levels on childhood leukemia incidence.

    PubMed

    Teepen, Jop C; van Dijck, Jos A A M

    2012-08-15

    The increasing exposure to electromagnetic fields (EMFs) has raised concern, as increased exposure may result in an increased risk of childhood leukemia (CL). Besides a short introduction of CL and EMF, our article gives an evaluation of the evidence of a causal relation between EMF and CL by critically appraising the epidemiological and biological evidence. The potential impact is also estimated by the population attributable risk. The etiology of CL is largely unknown, but is probably multifactorial. EMF may be one of the environmental exposures involved. Three pooled analyses of case-control studies showed a 1.4- to 1.7-fold increased CL risk for extremely low-frequency EMF (ELF-EMF) exposure levels above 0.3 μT. Several biases may have played a role in these studies, but are unlikely to fully explain the increased risk. For effects of radiofrequency ELF evidence is lacking. None of the proposed biological mechanisms by which ELF-EMF might cause CL have been confirmed. The estimated overall population attributable risk was 1.9%, with the highest estimates in Northern America and Brazil (4.2% and 4.1%, respectively). The potential impact of EMF exposure on public health is probably limited, although in some countries exposure might be relatively high and thus might have a more substantial impact. We recommend nationwide surveys to gain more insight into the contemporary exposure levels among children. Reducing exposure from power lines near densely populated areas and schools is advised. Future epidemiological studies should focus on limiting bias. Copyright © 2012 UICC.

  12. High fluoride exposure in hemodialysis patients.

    PubMed

    Bello, V A; Gitelman, H J

    1990-04-01

    The observation of higher plasma flouride levels in our hemodialysis (HD) patients than our continuous ambulatory peritoneal dialysis (CAPD) patients (4.0 +/- 0.5 mumol/L [n = 17] v 2.5 +/- 0.3 mumol/L [n = 17], P less than 0.005) prompted an evaluation of fluoride metabolism during HD. We found that serum fluoride was completely ultrafiltrable across cuprophane membranes (99% +/- 4%) and that HD produced acute changes in plasma fluoride levels that correlated well with the fluoride gradient between plasma and dialysis fluid at the start of dialysis. Our HD fluids contained significantly higher fluoride concentrations than were present in commercially prepared peritoneal dialysis fluid. Our fluids are prepared from fluoridated tap water that is purified by reverse osmosis (RO). We conclude that the different concentrations of fluoride in our dialysis fluids account for the differences in the plasma flouride concentrations between our dialysis groups. Since many HD units rely on RO systems to purify fluoridated tap water, it is likely that many HD patients are being exposed inadvertently to increased concentrations of fluoride.

  13. Analysis of breast milk to assess exposure to chlorinated contaminants in Kazakstan: high levels of 2,3,7, 8-tetrachlorodibenzo-p-dioxin (TCDD) in agricultural villages of southern Kazakstan.

    PubMed Central

    Hooper, K; Petreas, M X; Chuvakova, T; Kazbekova, G; Druz, N; Seminova, G; Sharmanov, T; Hayward, D; She, J; Visita, P; Winkler, J; McKinney, M; Wade, T J; Grassman, J; Stephens, R D

    1998-01-01

    To assess levels of chlorinated contaminants in breast milk, we measured organochlorine pesticides, polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs) in breast milk samples collected in 1994 according to the World Health Organization protocol from 92 donors that were representative of regional populations in southern Kazakstan. High levels (10-120 pg/g fat) of 2,3,7, 8-tetrachlorodibenzo-p-dioxin (TCDD), the most toxic of the PCDD/PCDF congeners, were found in breast milk samples from an agricultural region. TCDD was the major contributor (75%) to the international toxicity equivalents of these samples. The same distinctive PCDD/PCDF congener pattern was found in 15 breast milk samples and 4 serum samples collected in 1996 in a follow-up study, and has now been confirmed by three analytical laboratories. Images Figure 1 Figure 2 Figure 3 Figure 4 PMID:9831540

  14. Estimating Margin of Exposure to Thyroid Peroxidase Inhibitors Using High-Throughput in vitro Data, High-Throughput Exposure Modeling, and Physiologically Based Pharmacokinetic/Pharmacodynamic Modeling

    PubMed Central

    Leonard, Jeremy A.; Tan, Yu-Mei; Gilbert, Mary; Isaacs, Kristin; El-Masri, Hisham

    2016-01-01

    Some pharmaceuticals and environmental chemicals bind the thyroid peroxidase (TPO) enzyme and disrupt thyroid hormone production. The potential for TPO inhibition is a function of both the binding affinity and concentration of the chemical within the thyroid gland. The former can be determined through in vitro assays, and the latter is influenced by pharmacokinetic properties, along with environmental exposure levels. In this study, a physiologically based pharmacokinetic (PBPK) model was integrated with a pharmacodynamic (PD) model to establish internal doses capable of inhibiting TPO in relation to external exposure levels predicted through exposure modeling. The PBPK/PD model was evaluated using published serum or thyroid gland chemical concentrations or circulating thyroxine (T4) and triiodothyronine (T3) hormone levels measured in rats and humans. After evaluation, the model was used to estimate human equivalent intake doses resulting in reduction of T4 and T3 levels by 10% (ED10) for 6 chemicals of varying TPO-inhibiting potencies. These chemicals were methimazole, 6-propylthiouracil, resorcinol, benzophenone-2, 2-mercaptobenzothiazole, and triclosan. Margin of exposure values were estimated for these chemicals using the ED10 and predicted population exposure levels for females of child-bearing age. The modeling approach presented here revealed that examining hazard or exposure alone when prioritizing chemicals for risk assessment may be insufficient, and that consideration of pharmacokinetic properties is warranted. This approach also provides a mechanism for integrating in vitro data, pharmacokinetic properties, and exposure levels predicted through high-throughput means when interpreting adverse outcome pathways based on biological responses. PMID:26865668

  15. Effects of low-level hexabromocyclododecane (HBCD) exposure on cardiac development in zebrafish embryos.

    PubMed

    Wu, Meifang; Zuo, Zhenghong; Li, Bowen; Huang, Lixing; Chen, Meng; Wang, Chonggang

    2013-10-01

    Hexabromocyclododecane (HBCD) is one of the most widely used brominated flame retardants. In the present study, zebrafish embryos were exposed to HBCD at the low concentrations of 0, 2, 20 and 200 nM. The results showed HBCD exposure resulted in an increase in heart rate and cardiac arrhythmia after exposure for 72 h, though the survival rate and the whole malformation rate were not significantly affected. These results demonstrated that the heart might be a target of HBCD. Low-level HBCD exposure may not share the same mechanisms as exposure to high concentrations, since no obvious increase of apoptotic cells around the heart was observed in the HBCD-treated groups. It was observed that the expression of Tbx5 and Nkx2.5 was significantly elevated by HBCD treatment in a dose-dependent manner using real-time quantitative PCR, which may be mainly responsible for the alteration of heart rate, given that Tbx5 and Nkx2.5 are two factors regulating ventricle conduction. The mRNA expression of RyR2 and Atp2a2b (SERCA2a) was up-regulated in the exposure group, which may be one of reasons to affect the normal heart rate, since SERCA2a and RyR2 play an important role in calcium ion transport of cadiomyocytes. However, HBCD exposure did not significantly change the expression of Actc1l, Tnnt2, and Myh6, which are mainly muscle contractile genes that play key roles in the formation of cardiac structure. These results were consistent with the lack of effect seen on the other measurements of cardiac function, end diastolic volume, end-systolic volume, stroke volume, and cardiac output.

  16. Reduced exercise time in competitive simulations consequent to low level ozone exposure

    SciTech Connect

    Schelegle, E.S.; Adams, W.C.

    1986-08-01

    Ten highly trained endurance athletes were studied to determine the effects of exposure to low ozone (O/sub 3/) concentrations on simulated competitive endurance performance and associated physiological and subjective symptom responses. Each subject was randomly exposed to filtered air (FA), and to 0.12, 0.18, and 0.24 ppm O/sub 3/ while performing a 1 h competitive simulation protocol on a bicycle ergometer. Endurance performance was evaluated by the number of subjects unable to complete rides (last 30 min at an intense work load of approximately 86% VO/sub 2/max). All subjects completed the FA exposure, whereas one, five, and seven subjects did not complete the 0.12, 0.18, and 0.24 ppm O/sub 3/ exposures, respectively. Statistical analysis indicated a significant (P less than 0.05) increase in the inability of subjects to complete the competitive simulations with increasing O/sub 3/ concentration, including a significant difference between the 0.24 ppm O/sub 3/ and FA exposure. Significant decreases (P less than 0.05) were also observed following the 0.18 and 0.24 ppm O/sub 3/ exposures, respectively, in forced vital capacity (-7.8 and -9.9%), and forced expiratory volume in 1 s (-5.8 and -10.5%). No significant O/sub 3/ effect was observed for exercise respiratory metabolism or ventilatory pattern responses. However, the number of reported subjective symptoms increased significantly following the 0.18 and 0.24 ppm O/sub 3/ protocols. These data demonstrate significant decrements in simulated competitive endurance performance and in pulmonary function, with accompanying enhanced subjective symptoms, following exposure to low O/sub 3/ levels commonly observed in numerous metropolitan environments during the summer months.

  17. Does the Access to Sun Exposure Ensure Adequate Levels of 25-Hydroxyvitamin D?

    PubMed

    Damaso, Ênio Luis; Paula, Francisco José Albuquerque de; Franceschini, Silvio Antônio; Vieira, Carolina Sales; Ferriani, Rui Alberto; Silva de Sá, Marcos Felipe; Lara, Lucia Alves da Silva

    2017-03-01

    Objectives To assess the prevalence of hypovitaminosis D, altered arterial blood pressure, and serum levels of glucose and lipids in community-dwelling women in the city of Ribeirão Preto, in the southeast of Brazil. Methods This was a cross-sectional study of women aged 40-70 years old. Calcium intake and level of sun exposure were assessed by means of a questionnaire. A blood sample was used to determine glucose, lipid profile and 25-hydroxyvitamin D (25[OH]D) concentration. Results Ninety-one women were enrolled (age = 54.2 ± 7.1 years). The mean serum 25(OH)D concentration was 25.7 ± 8.9 ng/mL. A total of 24 (26.4%) women had 25(OH)D levels < 20 ng/mL. Seventy women (76.9%) had 25(OH)D levels < 30 ng/mL. Seventy-five women (90.4%) had inadequate calcium intake, and 61 women (67%) had appropriate sun exposure, 49 of whom (80.3%) had serum 25(OH)D levels < 30 ng/mL. Conclusion This study indicates that even in community-dwelling women, living in a city with high sun exposure, serum levels of 25(OH)D > 30 ng/ml are hardly reached. Thus, it is probable that other intrinsic factors besides sun exposure may regulate the levels of vitamin D. Thieme-Revinter Publicações Ltda Rio de Janeiro, Brazil.

  18. Early changes to oxidative stress levels following exposure to formaldehyde in ICR mice.

    PubMed

    Matsuoka, Takashi; Takaki, Atsushi; Ohtaki, Hirokazu; Shioda, Seiji

    2010-10-01

    Formaldehyde (FA) is a commonly used chemical in everyday life and can react with many molecules in the human body. Although toxicity has been reported, exposure to FA has also been shown to have beneficial effects or no effect at all. In the present study, we examined the effect of FA inhalation on oxidative stress and inflammation in mice. Male adult ICR mice were exposed FA in gaseous form (0.1 ppm), and blood, urine, brain, lung and liver were obtained for 24 hr. Levels of 8-hydroxy-2'-deoxyguanosine (8OHdG) and NO(3)(-) were then determined by HPLC. A second group of mice were injected with 5 mg/kg lipopolysaccharide (LPS) after 24 hr of FA (3 ppm) inhalation and blood and organs were assayed for NO(3)(-) level and SOD activity. After exposure to a low dose of FA (0.1 ppm), the 8OHdG/dG ratio significantly increased in plasma. However, the ratio in urine and organs significantly decreased during 24 hr of FA exposure. The NO(3)(-) levels mirrored the 8OHdG/dG ratio. After 24 hr exposure to a high dose of FA (3 ppm), NO(3)(-) levels in plasma and liver were significantly lower than in control mice exposed to air only. The SOD activity of blood and urine were conversely increased in FA exposed animals. In the present study, we suggest that inhalation of FA at low doses influences the oxidative stress response in a tissue-specific manner. The FA may partially alleviate in some tissues like preconditioning in oxidative stress.

  19. Historical occupational isocyanate exposure levels in two Canadian provinces.

    PubMed

    Hon, Chun-Yip; Peters, Cheryl E; Jardine, Katherine J; Arrandale, Victoria H

    2017-01-01

    Isocyanates such as toluene 2, 4-diisocyanate (TDI), methylene bisphenyl isocyanate (MDI), and hexamethylene diisocyanate (HDI) are known sensitizers and exposure to these chemicals can result in isocyanate-induced asthma-the leading cause of occupational asthma. A newly created exposure database was available containing occupational isocyanate measurements spanning 1981-1996 from Ontario and British Columbia (BC)-two of the largest provinces in Canada. The aim was to describe the historical measurements relative to exposure thresholds, ascertain differences in the data between provinces, and identify time trends. Descriptive statistics of the observations were summarized and stratified by isocyanate species and province. Chi-square tests and Student's t-test were performed to determine differences between provinces. To investigate time trends in the odds of a measurement exceeding the limit of detection (LOD) and time-weighted average (TWA), mixed effects logistic regression models were constructed. In total, 6,984 isocyanate measurements were analyzed, the majority of which were below the LOD (79%). Overall, 8.3% of samples were in excess of the 2014 TLV-TWA of 0.005 ppm. Comparing the two provinces, the proportion of samples exceeding the LOD and TLV-TWA was greater in BC for all isocyanate species. Differences in time trends were also observed between provinces-the odds of a sample exceeding the TLV-TWA decreased over time in the case of MDI (Ontario only), TDI (both Ontario and BC), and other isocyanates (BC only). Our finding that a majority of the exposure measurements was below the LOD is similar to that reported by others. Differences between provinces may be due the fact that isocyanates are classified as a designated substance in Ontario and must adhere to specific exposure control regulations. Limitations of the database, such as finite number of variables and measurements available until 1996 only, presents challenges for more in-depth analysis and

  20. Cigarettes with different nicotine levels affect sensory perception and levels of biomarkers of exposure in adult smokers.

    PubMed

    McKinney, Diana L; Frost-Pineda, Kimberly; Oldham, Michael J; Fisher, Michael T; Wang, Jingzhu; Gogova, Maria; Kobal, Gerd

    2014-07-01

    Few clinical studies involving cigarettes have provided a comprehensive picture of smoke exposure, test article characterization, and insights into sensory properties combined. The purpose of these pilot studies was to determine whether cigarettes with different levels of nicotine but similar tar levels would affect sensory experience or smoking behavior so as to significantly alter levels of selected biomarkers of exposure (BOE). In 2 confined, double-blind studies, 120 adult smokers switched from Marlboro Gold cigarettes at baseline to either 1 of 2 lower nicotine cigarettes or 1 of 2 higher nicotine cigarettes and then to the other cigarette after 5 days. Urinary excretion of exposure biomarkers (nicotine equivalents [NE], total and free 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol [NNAL], 1-hydroxypyrene, and 3-hydroxypropyl mercapturic acid) as well as carboxyhemoglobin and plasma cotinine were measured at baseline, Day 5, and Day 10. Daily cigarette consumption was monitored and sensory characteristics were rated for each cigarette. With higher nicotine yield, urine NE, urine total NNAL, and plasma cotinine increased while nonnicotine BOE decreased without changes in cigarette consumption. In contrast, with lower nicotine yield, urine NE, urine total NNAL, and plasma cotinine dropped while nonnicotine BOE and cigarettes per day increased. Higher nicotine cigarettes were rated harsher and stronger than at baseline while lower nicotine cigarettes were less strong. All 4 test cigarettes were highly disliked. These studies demonstrate that abrupt increases or decreases in nicotine and the resulting sensory changes impact BOE through changes in intensity or frequency of smoking. © The Author 2014. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  1. Aluminum exposure for 60days at an equivalent human dietary level promotes peripheral dysfunction in rats.

    PubMed

    Martinez, Caroline Silveira; Vera, Gema; Ocio, José Antonio Uranga; Peçanha, Franck Maciel; Vassallo, Dalton Valentim; Miguel, Marta; Wiggers, Giulia Alessandra

    2017-08-25

    Aluminum (Al) is a neurotoxic associated with a number of chronic human diseases. We investigated the effects of Al exposure at doses similar to human dietary levels and at a high level exposure to Al on the peripheral nervous system. Wistar male rats were divided into two major groups and received orally: 1) First group - Low level - rats were subdivided and treated for 60days: a) Control - received ultrapure water; b) AlCl3 - received Al at 8.3mg/kg body weight (bw) for 60days; and 2) Second group - High level - rats were subdivided and treated for 42days: C) Control - received ultrapure water through oral gavage; d) AlCl3 - received Al at 100mg/kg bw for 42days. Von Frey hair test, plantar test, the presence of catalepsy and the spontaneous motor activity were investigated. Reactive oxygen species, lipid peroxidation and total antioxidant capacity, immunohistochemistry to investigate the nerve inflammation and, the specific presence of Al in the sciatic nerve fibers were investigated. Al exposure at a representative human dietary level promotes the development of mechanical allodynia, catalepsy, increased inflammation in the sciatic nerve, systemic oxidative stress and, is able to be retained in the sciatic nerve. The effects of low-dose Al were similar to those found in rats exposed to Al at a dose much higher (100mg/kg). Our findings suggest that Al may be considered toxic for the peripheral nervous system, thus inducing peripheral dysfunction. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Exposure to extremely low frequency electromagnetic fields alters the behaviour, physiology and stress protein levels of desert locusts

    PubMed Central

    Wyszkowska, Joanna; Shepherd, Sebastian; Sharkh, Suleiman; Jackson, Christopher W.; Newland, Philip L.

    2016-01-01

    Electromagnetic fields (EMFs) are present throughout the modern world and are derived from many man-made sources including overhead transmission lines. The risks of extremely-low frequency (ELF) electromagnetic fields are particularly poorly understood especially at high field strengths as they are rarely encountered at ground level. Flying insects, however, can approach close to high field strength transmission lines prompting the question as to how these high levels of exposure affect behaviour and physiology. Here we utilise the accessible nervous system of the locust to ask how exposure to high levels of ELF EMF impact at multiple levels. We show that exposure to ELF EMFs above 4 mT leads to reduced walking. Moreover, intracellular recordings from an identified motor neuron, the fast extensor tibiae motor neuron, show increased spike latency and a broadening of its spike in exposed animals. In addition, hind leg kick force, produced by stimulating the extensor tibiae muscle, was reduced following exposure, while stress-protein levels (Hsp70) increased. Together these results suggest that ELF EMF exposure has the capacity to cause dramatic effects from behaviour to physiology and protein expression, and this study lays the foundation to explore the ecological significance of these effects in other flying insects. PMID:27808167

  3. Exposure to extremely low frequency electromagnetic fields alters the behaviour, physiology and stress protein levels of desert locusts.

    PubMed

    Wyszkowska, Joanna; Shepherd, Sebastian; Sharkh, Suleiman; Jackson, Christopher W; Newland, Philip L

    2016-11-03

    Electromagnetic fields (EMFs) are present throughout the modern world and are derived from many man-made sources including overhead transmission lines. The risks of extremely-low frequency (ELF) electromagnetic fields are particularly poorly understood especially at high field strengths as they are rarely encountered at ground level. Flying insects, however, can approach close to high field strength transmission lines prompting the question as to how these high levels of exposure affect behaviour and physiology. Here we utilise the accessible nervous system of the locust to ask how exposure to high levels of ELF EMF impact at multiple levels. We show that exposure to ELF EMFs above 4 mT leads to reduced walking. Moreover, intracellular recordings from an identified motor neuron, the fast extensor tibiae motor neuron, show increased spike latency and a broadening of its spike in exposed animals. In addition, hind leg kick force, produced by stimulating the extensor tibiae muscle, was reduced following exposure, while stress-protein levels (Hsp70) increased. Together these results suggest that ELF EMF exposure has the capacity to cause dramatic effects from behaviour to physiology and protein expression, and this study lays the foundation to explore the ecological significance of these effects in other flying insects.

  4. High-Throughput Models for Exposure-Based Chemical ...

    EPA Pesticide Factsheets

    The United States Environmental Protection Agency (U.S. EPA) must characterize potential risks to human health and the environment associated with manufacture and use of thousands of chemicals. High-throughput screening (HTS) for biological activity allows the ToxCast research program to prioritize chemical inventories for potential hazard. Similar capabilities for estimating exposure potential would support rapid risk-based prioritization for chemicals with limited information; here, we propose a framework for high-throughput exposure assessment. To demonstrate application, an analysis was conducted that predicts human exposure potential for chemicals and estimates uncertainty in these predictions by comparison to biomonitoring data. We evaluated 1936 chemicals using far-field mass balance human exposure models (USEtox and RAIDAR) and an indicator for indoor and/or consumer use. These predictions were compared to exposures inferred by Bayesian analysis from urine concentrations for 82 chemicals reported in the National Health and Nutrition Examination Survey (NHANES). Joint regression on all factors provided a calibrated consensus prediction, the variance of which serves as an empirical determination of uncertainty for prioritization on absolute exposure potential. Information on use was found to be most predictive; generally, chemicals above the limit of detection in NHANES had consumer/indoor use. Coupled with hazard HTS, exposure HTS can place risk earlie

  5. High Throughput Heuristics for Prioritizing Human Exposure to ...

    EPA Pesticide Factsheets

    The risk posed to human health by any of the thousands of untested anthropogenic chemicals in our environment is a function of both the potential hazard presented by the chemical, and the possibility of being exposed. Without the capacity to make quantitative, albeit uncertain, forecasts of exposure, the putative risk of adverse health effect from a chemical cannot be evaluated. We used Bayesian methodology to infer ranges of exposure intakes that are consistent with biomarkers of chemical exposures identified in urine samples from the U.S. population by the National Health and Nutrition Examination Survey (NHANES). We perform linear regression on inferred exposure for demographic subsets of NHANES demarked by age, gender, and weight using high throughput chemical descriptors gleaned from databases and chemical structure-based calculators. We find that five of these descriptors are capable of explaining roughly 50% of the variability across chemicals for all the demographic groups examined, including children aged 6-11. For the thousands of chemicals with no other source of information, this approach allows rapid and efficient prediction of average exposure intake of environmental chemicals. The methods described by this manuscript provide a highly improved methodology for HTS of human exposure to environmental chemicals. The manuscript includes a ranking of 7785 environmental chemicals with respect to potential human exposure, including most of the Tox21 in vit

  6. Exposure to aerosols during high-pressure cleaning and relationship with health effects.

    PubMed

    Madsen, Anne Mette; Matthiesen, Christoffer B

    2013-01-01

    In different occupations cleaning has been identified as the work task causing the highest exposure to aerosol components. High pressure cleaning (hpc) is a cleaning method used in many environments and seems to be considered as a cleaning method causing high exposure. In the presented study, the literature concerning exposure to aerosols during hpc is reviewed. Only a few studies have been published about exposure to aerosols during hpc. Exposure during hpc has been measured on farms, at waste water treatment plants, at a chemical factory and for graffiti removers. High exposures to bacterial endotoxin or chemical components were found in these environments during hpc. Few cases have been published documenting acute health effects caused by exposure to microorganisms and endotoxin during hpc. High pressure cleaners are also used in private settings but no papers have been found about exposure or related health effects during work in private settings. The use of clean water during hpc is important since effluent water or roof-collected rain water can cause a higher exposure to bioaerosols and related health effects. However, tap water in some areas also seems to have a high content of endotoxin, and this too should be considered when deliberating the protection of the airways of workers. Different attempts have been made to reduce workers' exposure and the health effects of exposure during hpc, among them the use of respiratory protection, ventilation and automation of work processes have been used with some degree of success. However, some of these studies only show tendencies. A high number of repeats seem to be necessary in order to obtain conclusive results. The material to be cleaned, as well as the degree of dirtiness, highly influences the exposure level; therefore, in comparative studies it is important also to consider these parameters. No study has been found which compares exposure during the use of different high pressure cleaners. The comparison of

  7. Fabrication of high exposure nuclear fuel pellets

    DOEpatents

    Frederickson, James R.

    1987-01-01

    A method is disclosed for making a fuel pellet for a nuclear reactor. A mixture is prepared of PuO.sub.2 and UO.sub.2 powders, where the mixture contains at least about 30% PuO.sub.2, and where at least about 12% of the Pu is the Pu.sup.240 isotope. To this mixture is added about 0.3 to about 5% of a binder having a melting point of at least about 250.degree. F. The mixture is pressed to form a slug and the slug is granulated. Up to about 4.7% of a lubricant having a melting point of at least about 330.degree. F. is added to the granulated slug. Both the binder and the lubricant are selected from a group consisting of polyvinyl carboxylate, polyvinyl alcohol, naturally occurring high molecular weight cellulosic polymers, chemically modified high molecular weight cellulosic polymers, and mixtures thereof. The mixture is pressed to form a pellet and the pellet is sintered.

  8. Biomonitoring of organophosphate exposure of pesticide sprayers and comparison of exposure levels with other population groups in Thessaly (Greece).

    PubMed

    Koureas, Michalis; Tsakalof, Andreas; Tzatzarakis, Manolis; Vakonaki, Elena; Tsatsakis, Aristidis; Hadjichristodoulou, Christos

    2014-02-01

    To evaluate the exposure of different population groups in Thessaly (Greece) to organophosphate pesticides (OPs) and investigate the dependence of exposure levels on pesticide application practices, personal protective and hygienic measures taken. For the exposure assessment, four dialkyl phosphate (DAP) metabolites of organophosphate pesticides were quantified in spot urine samples of 77 pesticide sprayers, 75 residents of the studied agricultural area non-involved in agricultural activities and 112 urban residents who served as a control group. Structured questionnaires were used to record demographic characteristics, pesticide application parameters and protective measures taken. Univariate and multivariate analysis of the obtained cross-sectional data was performed to identify potential risk factors associated with biomarker levels. It was found that total DAP median level in the sprayers' group was 24.9 μg/g creatinine (IQR: 13.0-42.1), while the rural and urban residents had significantly lower (p<0.001) levels of 11.3 μg/g creatinine (IQR: 5.3-18.7) and 11.9 μg/g creatinine (IQR: 6.3-20.3), respectively. In sprayers who had recently applied an OP pesticide (n=28), the median levels of DAP metabolites were 31.8 μg/g creatinine (IQR: 22.3-117.2). Logistic regression analysis showed that the use of full body coveralls while handling and spraying pesticides was significantly associated with lower DAP levels (OR 4.05, 95% CI 1.22 to 13.46). Also, changing clothes immediately after accidental contamination of clothing with pesticide amounts was found to be significantly associated with lower exposure levels (OR 4.04, CI 1.05 to 15.57). Our study findings confirm the increased exposure to OPs in pesticide sprayers and underline the importance of protective measures especially those that focus on dermal exposure mitigation.

  9. Aluminum exposure for 60days at human dietary levels impairs spermatogenesis and sperm quality in rats.

    PubMed

    Martinez, Caroline Silveira; Escobar, Alyne Gourlart; Uranga-Ocio, José Antonio; Peçanha, Franck Maciel; Vassallo, Dalton Valentim; Exley, Christopher; Miguel, Marta; Wiggers, Giulia Alessandra

    2017-08-18

    Concerns about environmental aluminum (Al) and reproductive health have been raised. We investigated the effects of Al exposure at a human relevant dietary level and a high level exposure to Al. Experiment 1 (Lower level) rats were treated orally for 60 days: a) controls - ultrapure water; b) aluminum at 1.5mg/kg bw/day and c) aluminum at 8.3mg/kg bw/day. Experiment 2 (High level) rats were treated for 42 days: a) controls - ultrapure water; b) aluminum at 100mg/kg bw/day. Al decreased sperm count, daily sperm production, sperm motility, normal morphological sperm, impaired testis histology; increased oxidative stress in reproductive organs and inflammation in testis. Our study shows the specific presence of Al in the germinative cells and, that low concentrations of Al in testes (3.35μg/g) are sufficient to impair spermatogenesis and sperm quality. Our findings provide a better understanding of the reproductive health risk of Al. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Exposure sources and reasons for testing among women with low blood lead levels.

    PubMed

    Zhu, Motao; Fitzgerald, Edward F; Gelberg, Kitty H

    2011-08-01

    Previous research has focused on highly elevated blood lead (PbB). This study examined reasons for testing and potential sources of exposure among women with PbBs less than 0.72 μmol/l (15 μg/dl). A questionnaire was mailed to 18- to 49-year-old women in upstate New York, USA, who were PbB tested in 2007. The most common testing reason was pregnancy among 125 women who returned the questionnaire. Among women tested for PbB during pregnancy, doctors ordered approximately 80% of tests regardless of lead level. Few women with PbBs less than 0.24 μmol/l (5 μg/dl) reported a potential source of lead exposure. However, among women with PbBs of 0.24-0.71 μmol/L (5-14.9 μg/dl), 29.2% had a job and 21.2% had a hobby with potential lead exposure. There are systematic differences in reasons for testing and exposure sources among women with PbBs less than 0.72 μmol/l and these differences have implications for screening.

  11. Low level exposure to the flame retardant BDE-209 reduces thyroid hormone levels and disrupts thyroid signaling in fathead minnows.

    PubMed

    Noyes, Pamela D; Lema, Sean C; Macaulay, Laura J; Douglas, Nora K; Stapleton, Heather M

    2013-09-03

    Polybrominated diphenyl ether (PBDE) flame retardants have been shown to disrupt thyroid hormone regulation, neurodevelopment, and reproduction in some animals. However, effects of the most heavily used PBDE, decabromodiphenyl ether (BDE-209), on thyroid functioning remain unclear. This study examined low-dose effects of BDE-209 on thyroid hormone levels and signaling in fathead minnows. Adult males received dietary exposures of BDE-209 at a low dose (∼3 ng/g bw-day) and high dose (∼300 ng/g bw-day) for 28 days followed by a 14-day depuration to evaluate recovery. Compared to controls, fish exposed to the low dose for 28 days experienced a 53% and 46% decline in circulating total thyroxine (TT4) and 3,5,3'-triiodothyronine (TT3), respectively, while TT4 and TT3 deficits at the high dose were 59% and 62%. Brain deiodinase activity (T4-ORD) was reduced by ∼65% at both doses. BDE-209 elevated the relative mRNA expression of genes encoding deiodinases, nuclear thyroid receptors, and membrane transporters in the brain and liver in patterns that varied with time and dose, likely in compensation to hypothyroidism. Declines in the gonadal-somatic index (GSI) and increased mortality were also measured. Effects at the low dose were consistent with the high dose, suggesting nonlinear relationships between BDE-209 exposures and thyroid dysfunction.

  12. Low-level arsenic exposure via drinking water consumption and female fecundity - A preliminary investigation.

    PubMed

    Susko, Michele L; Bloom, Michael S; Neamtiu, Iulia A; Appleton, Allison A; Surdu, Simona; Pop, Cristian; Fitzgerald, Edward F; Anastasiu, Doru; Gurzau, Eugen S

    2017-04-01

    High level arsenic exposure is associated with reproductive toxicity in experimental and observational studies; however, few data exist to assess risks at low levels. Even less data are available to evaluate the impact of low level arsenic exposure on human fecundity. Our aim in this pilot study was a preliminary evaluation of associations between low level drinking water arsenic contamination and female fecundity. This retrospective study was conducted among women previously recruited to a hospital-based case-control study of spontaneous pregnancy loss in Timiṣ County, Romania. Women (n=94) with planned pregnancies of 5-20 weeks gestation completed a comprehensive physician-administered study questionnaire and reported the number of menstrual cycles attempting to conceive as the time to pregnancy (TTP). Drinking water samples were collected from residential drinking water sources and we determined arsenic levels using hydride generation-atomic absorption spectrometry (HG-AAS). Multivariable Cox-proportional hazards regression with Efron approximation was employed to evaluate TTP as a function of drinking water arsenic concentrations among planned pregnancies, adjusted for covariates. There was no main effect for drinking water arsenic exposure, yet the conditional probability for pregnancy was modestly lower among arsenic exposed women with longer TTPs, relative to women with shorter TTPs, and relative to unexposed women. For example, 1µg/L average drinking water arsenic conferred 5%, 8%, and 10% lower likelihoods for pregnancy in the 6th, 9th, and 12th cycles, respectively (P=0.01). While preliminary, our results suggest that low level arsenic contamination in residential drinking water sources may further impair fecundity among women with longer waiting times; however, this hypothesis requires confirmation by a future, more definitive study. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Trichloroethene levels in human blood and exhaled breath from controlled inhalation exposure.

    PubMed Central

    Pleil, J D; Fisher, J W; Lindstrom, A B

    1998-01-01

    The organic constituents of exhaled human breath are representative of bloodborne concentrations through gas exchange in the blood/breath interface in the lungs. The presence of specific compounds can be an indicator of recent exposure or represent a biological response of the subject. For volatile organic compounds, sampling and analysis of breath is preferred to direct measurement from blood samples because breath collection is noninvasive, potentially infectious waste is avoided, the sample supply is essentially limitless, and the measurement of gas-phase analytes is much simpler in a gas matrix rather than in a complex biological tissue such as blood. However, to assess the distribution of a contaminant in the body requires a reasonable estimate of the blood level. We have investigated the use of noninvasive breath measurements as a surrogate for blood measurements for (high) occupational levels of trichloroethene in a controlled exposure experiment. Subjects were placed in an exposure chamber for 24 hr; they were exposed to 100 parts per million by volume trichloroethene for the initial 4 hr and to purified air for the remaining 20 hr. Matched breath and blood samples were collected periodically during the experiment. We modeled the resulting concentration data with respect to their time course and assessed the blood/breath relationship during the exposure (uptake) period and during the postexposure (elimination) period. Estimates for peak blood levels, compartmental distribution, and time constants were calculated from breath data and compared to direct blood measurements to assess the validity of the breath measurement methodology. Blood/breath partition coefficients were studied during both uptake and elimination. At equilibrium conditions at the end of the exposure, we could predict actual blood levels using breath elimination curve calculations and a literature value partition coefficient with a mean ratio of calculated:measured of 0.98 and standard error

  14. Estimating National-Level Exposure to Antineoplastic Agents in the Workplace: CAREX Canada Findings and Future Research Needs.

    PubMed

    Hall, Amy L; Demers, Paul A; Astrakianakis, George; Ge, Calvin; Peters, Cheryl E

    2017-07-01

    Occupational exposure to antineoplastic agents occurs in various environments and is associated with increased cancer risk and adverse reproductive outcomes. National-level information describing the location and extent of occupational exposure to antineoplastic agents is unavailable in Canada and most other countries. CAREX Canada aimed to estimate the prevalence and relative levels of occupational exposures to antineoplastic agents across work setting, occupation, and sex. 'Exposure' was defined as any potential for worker contact with antineoplastic agents. Baseline numbers of licensed workers were obtained from their respective professional bodies. For unlicensed workers, Census data or data extrapolated from human resources reports (e.g., staffing ratios) were used. Prevalence was estimated by combining population estimates with exposure proportions from peer-reviewed and grey literature. Exposure levels (classified as low, moderate, and high) by occupation and work setting were estimated qualitatively by combining estimates of contact frequency and exposure control practices. Approximately 75000 Canadians (0.42% of the total workforce) are estimated as occupationally exposed to antineoplastic agents; over 75% are female. The largest occupational group exposed to antineoplastic agents is community pharmacy workers, with 30200 exposed. By work setting, 39000 workers (52% of all exposed) are located in non-hospital settings; the remaining 48% are exposed in hospitals. The majority (75%) of workers are in the moderate exposure category. These estimates of the prevalence and location of occupational exposures to antineoplastic agents could be used to identify high-risk groups, estimate disease burden, and target new research and prevention activities. The limited secondary data available for developing these estimates highlights the need for increased quantitative measurement and documentation of antineoplastic agent contamination and exposure, particularly in

  15. Chronic corticosterone exposure reduces hippocampal glycogen level and induces depression-like behavior in mice.

    PubMed

    Zhang, Hui-yu; Zhao, Yu-nan; Wang, Zhong-li; Huang, Yu-fang

    2015-01-01

    Long-term exposure to stress or high glucocorticoid levels leads to depression-like behavior in rodents; however, the cause remains unknown. Increasing evidence shows that astrocytes, the most abundant cells in the central nervous system (CNS), are important to the nervous system. Astrocytes nourish and protect the neurons, and serve as glycogen repositories for the brain. The metabolic process of glycogen, which is closely linked to neuronal activity, can supply sufficient energy substrates for neurons. The research team probed into the effects of chronic corticosterone (CORT) exposure on the glycogen level of astrocytes in the hippocampal tissues of male C57BL/6N mice in this study. The results showed that chronic CORT injection reduced hippocampal neurofilament light protein (NF-L) and synaptophysin (SYP) levels, induced depression-like behavior in male mice, reduced hippocampal glycogen level and glycogen synthase activity, and increased glycogen phosphorylase activity. The results suggested that the reduction of the hippocampal glycogen level may be the mechanism by which chronic CORT treatment damages hippocampal neurons and induces depression-like behavior in male mice.

  16. Chronic corticosterone exposure reduces hippocampal glycogen level and induces depression-like behavior in mice*

    PubMed Central

    Zhang, Hui-yu; Zhao, Yu-nan; Wang, Zhong-li; Huang, Yu-fang

    2015-01-01

    Long-term exposure to stress or high glucocorticoid levels leads to depression-like behavior in rodents; however, the cause remains unknown. Increasing evidence shows that astrocytes, the most abundant cells in the central nervous system (CNS), are important to the nervous system. Astrocytes nourish and protect the neurons, and serve as glycogen repositories for the brain. The metabolic process of glycogen, which is closely linked to neuronal activity, can supply sufficient energy substrates for neurons. The research team probed into the effects of chronic corticosterone (CORT) exposure on the glycogen level of astrocytes in the hippocampal tissues of male C57BL/6N mice in this study. The results showed that chronic CORT injection reduced hippocampal neurofilament light protein (NF-L) and synaptophysin (SYP) levels, induced depression-like behavior in male mice, reduced hippocampal glycogen level and glycogen synthase activity, and increased glycogen phosphorylase activity. The results suggested that the reduction of the hippocampal glycogen level may be the mechanism by which chronic CORT treatment damages hippocampal neurons and induces depression-like behavior in male mice. PMID:25559957

  17. Lead exposure and behavioral changes: comparisons of four occupational groups with different levels of lead absorption.

    PubMed

    Valciukas, J A; Lilis, R; Singer, R; Fischbein, A; Anderson, H A; Glickman, L

    1980-01-01

    The association between lead absorption and objective psychological performance tests in five groups with different levels of lead absorption was studied in the following groups: (1) a control, non-lead-exposed group; (2) cable splicers, (3) cable manufactures, and (4) secondary lead smelter workers. The following performance tests were used: Block Design, Digit Symbol, and Embedded Figures. Age-corrected performance test scores and the average of three test scores (INDEX) were used throughout. A significant association between performance tests scores and increased lead absorption was found. Zinc protoporphyrin level was a more "powerful" (in the statistical sense) indicator of lead-induced CNS effects than blood lead levels. This study provides additional evidence that neurotoxic effects associated with occupational exposure to lead can be demonstrated by means of performance tests. It has been known and widely accepted that increased lead absorption is associated with "non-specific" subjective symptoms: tiredness, sleep disturbance, irritability, etc. Psychometric techniques (including an appropriate statistical analysis strategy) are highly sensitive for the early detection of CNS neurotoxicity, such as metal toxicity. Moreover, even in lead-exposed but asymptomatic individuals, a significant correlation (negative) between test scores and levels of lead absorption could be detected. It is concluded that workers exposed to lead at levels considered "safe" might be at risk of developing brain dysfunction with long term exposure.

  18. Secondhand smoke exposure in a rural high school.

    PubMed

    Lee, Kiyoung; Hahn, Ellen J; Riker, Carol A; Hoehne, Amber; White, Ashleigh; Greenwell, Devin; Thompson, Dyshel

    2007-08-01

    Although federal law requires all public schools to be smoke free, lack of compliance with the smoke-free policy is commonly reported. The aims of this study were to describe the indoor fine-particle (PM(2.5)) air pollution in a rural high school and surrounding public venues. This cross-sectional, nonexperimental study was conducted in Monroe County, Kentucky (population of 11,756). Fine-particle concentrations were measured in the high school and 5 public venues using spectrometers. Because of illegal student smoking, PM(2.5) concentrations were 19 times higher in the boys' student restroom than the National Ambient Air Quality Standard for outdoor air (670 vs. 35 microg/m(3)). The staff restrooms adjacent to the student restroom where staff did not smoke also showed high PM(2.5) levels. Average indoor air pollution in the public venues was 158 microg/m(3). Strict enforcement of smoke-free school policy and cessation resources are needed to reduce secondhand smoke exposure. Collaborative school-community campaigns involving parents, students, mass media, and community organizations may be effective in reducing the harm caused by tobacco. Implications for school nurses are discussed.

  19. Association between Blood Dioxin Level and Chronic Kidney Disease in an Endemic Area of Exposure.

    PubMed

    Huang, Chien-Yuan; Wu, Cheng-Long; Wu, Jin-Shang; Chang, Jung-Wei; Cheng, Ya-Yun; Kuo, Yau-Chang; Yang, Yi-Ching; Lee, Ching-Chang; Guo, How-Ran

    2016-01-01

    Dioxin is an industrial pollutant related to various diseases, but epidemiological data on its effects on the kidney are limited. Therefore, we conducted a study to evaluate the association between dioxin exposure and chronic kidney disease (CKD) and identify the related factors. We conducted a community-based cross-sectional study and recruited participants from an area where the residents were exposed to dioxin released from a factory. We defined a "high dioxin level" as polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) ≥ 20 pg WHO98-TEQDF/g lipid in the serum and defined CKD as having an estimated glomerular filtration rate (e-GFR) ≤ 60 mL/min/1.73m2 or a diagnosis of CKD by a physician. The renal function was assessed between 2005 and 2010, and we excluded those who had had kidney diseases before the study started. Comparisons between patients of CKD and those who did not have CKD were made to identify the risk factors for CKD. Of the 2898 participants, 1427 had high dioxin levels, and 156 had CKD. In the univariate analyses, CKD was associated with high dioxin levels, age, gender, metabolic syndrome, diabetes mellitus, hypertension, and high insulin and uric acid levels. After adjusting for other factors, we found high dioxin levels (adjusted odds ratio [AOR] = 1.76, 95% confidence interval [CI]: 1.04-2.99), female gender (AOR = 1.74, 95%CI: 1.20-2.53), hypertension (AOR = 1.68, 95%CI: 1.17-2.42), high insulin levels (AOR = 2.14, 95% CI: 1.26-3.61), high uric acid levels (AOR = 4.25, 95% CI: 2.92-6.20), and older age (AOR = 4.66, 95% CI: 1.87-11.62 for 40-64 year and AOR = 26.66, 95% CI: 10.51-67.62 for age ≥ 65 year) were independent predictors of CKD. A high dioxin level was associated with an increased prevalence of CKD. Therefore, the kidney function of populations with exposure to dioxin should be monitored.

  20. ENVIRONMENTAL MANGANESE: GUIDELINE EXPOSURE LEVELS, EVIDENCE OF HEALTH EFFECTS AND RESEARCH NEEDS.

    EPA Science Inventory

    Introduction. The ubiquitous element, manganese (Mn), is an essential nutrient, but toxic at excessive exposure levels. The US EPA, therefore, set guideline levels for Mn exposure through inhalation (reference concentration-RfC=0.05 g/m3) and ingestion (reference dose-RfD=0.14 m...

  1. ENVIRONMENTAL MANGANESE: GUIDELINE EXPOSURE LEVELS, EVIDENCE OF HEALTH EFFECTS AND RESEARCH NEEDS.

    EPA Science Inventory

    Introduction. The ubiquitous element, manganese (Mn), is an essential nutrient, but toxic at excessive exposure levels. The US EPA, therefore, set guideline levels for Mn exposure through inhalation (reference concentration-RfC=0.05 g/m3) and ingestion (reference dose-RfD=0.14 m...

  2. The levels of kerosene components in biological samples after repeated dermal exposure to kerosene in rats.

    PubMed

    Fujihara, Junko; Hieda, Yoko; Tsujino, Yoshio; Xue, Yuying; Takayama, Koji; Kimura, Kojiro; Dekio, Satoshi

    2004-04-01

    The current study was experimentally investigated using rats whether or not kerosene components are accumulated from daily repeated dermal exposure. Rats received daily 1h-exposure to kerosene for 5 days (5K), daily 1h-exposure for 4 days and left for 1 day (4KL), a single 1h-exposure (1K), a single 1h-exposure and left for 1 day (1KL), or a single 1h-exposure, sacrificed and left dead for 1 day (1KLD). Kerosene components, trimethylbenzenes (TMBs) and aliphatic hydrocarbons (AHCs) in blood and tissues were determined by GC-MS. In blood, almost the same concentrations of TMBs were detected in the rats sacrificed immediately after exposure (5K, 1K and 1KLD), and only trace levels were detected in the rats sacrificed 1 day after exposure (4 and 1KL). Almost the same levels of AHCs in blood were detected among groups except for the rats sacrificed 1 day after a single exposure (1KL), in which AHCs were slightly lower. These results suggest that (1) AHCs tend to be accumulated from daily exposure, while TMBs do not, (2) the proportions of detected kerosene components in blood can be an indicator of whether the last exposure occurred just before death or not, (3) the kerosene levels last at least 1 day without blood circulation.

  3. Chronic low-level domoic acid exposure alters gene transcription and impairs mitochondrial function in the CNS

    PubMed Central

    Hiolski, Emma M; Kendrick, Preston S; Frame, Elizabeth R; Myers, Mark S; Bammler, Theo K; Beyer, Richard P; Farin, Federico M; Wilkerson, Hui-wen; Smith, Donald R; Marcinek, David J; Lefebvre, Kathi A

    2014-01-01

    Domoic acid is an algal-derived seafood toxin that functions as a glutamate agonist and exerts excitotoxicity via overstimulation of glutamate receptors (AMPA, NMDA) in the central nervous system (CNS). At high (symptomatic) doses, domoic acid is well-known to cause seizures, brain lesions and memory loss; however, a significant knowledge gap exists regarding the health impacts of repeated low-level (asymptomatic) exposure. Here, we investigated the impacts of low-level repetitive domoic acid exposure on gene transcription and mitochondrial function in the vertebrate CNS using a zebrafish model in order to: 1) identify transcriptional biomarkers of exposure; and 2) examine potential pathophysiology that may occur in the absence of overt excitotoxic symptoms. We found that transcription of genes related to neurological function and development were significantly altered, and that asymptomatic exposure impaired mitochondrial function. Interestingly, the transcriptome response was highly-variable across the exposure duration (36 weeks), with little to no overlap of specific genes across the six exposure time points (2, 6, 12, 18, 24, and 36 weeks). Moreover, there were no apparent similarities at any time point with the gene transcriptome profile exhibited by the glud1 mouse model of chronic moderate excess glutamate release. These results suggest that although the fundamental mechanisms of toxicity may be similar, gene transcriptome responses to domoic acid exposure do not extrapolate well between different exposure durations. However, the observed impairment of mitochondrial function based on respiration rates and mitochondrial protein content suggests that repetitive low-level exposure does have fundamental cellular level impacts that could contribute to chronic health consequences. PMID:25033243

  4. The Association between Involuntary Smoking Exposure with Urine Cotinine Level and Blood Cadmium Level in General Non-Smoking Populations.

    PubMed

    Lee, Wanhyung; Lee, Seunghyun; Roh, Jaehoon; Won, Jong Uk; Yoon, Jin Ha

    2017-04-01

    Unintentional environmental exposure to toxicants is associated with an aggravated health status of the general population. Involuntary smoking (IS) exposure is one of the main routes to involuntary toxicants exposure. However, few studies have attempted to understand the environmental cadmium exposure by IS exposure in the general, non-smoking population. The purpose of the current study was to examine the relationship between blood cadmium level and IS level according to gender and age. We used the Korea National Health and Nutrition Examination Survey (KNHANES) IV-VI data that included heavy metal and urine cotinine sampling with IS exposure history. The final analysis comprised 3,493 adults (1,231 males and 2,262 females) and 395 adolescents (210 males and 185 females). Linear regression was performed to estimate the association between self-reported IS exposure with urine cotinine level and blood cadmium level in non-smokers with gender and age group stratification. In final regression model, the effect values (B) (standard errors [SE]) between blood cadmium and urine cotinine level in men was 0.0004 (0.0001) and 0.0006 (0.0002) in adults and adolescents, the B (SE) in women was 0.0006 (0.0002) and 0.0016 (0.0006) in adults and adolescents. Our study revealed, for the first time, a significant association between blood cadmium and IS exposure in non-smokers. Greater efforts are needed to improve environmental justices of the general population from IS, considering the severe harmful effects of involuntary exposure to even a low level of cadmium. © 2017 The Korean Academy of Medical Sciences.

  5. The Association between Involuntary Smoking Exposure with Urine Cotinine Level and Blood Cadmium Level in General Non-Smoking Populations

    PubMed Central

    2017-01-01

    Unintentional environmental exposure to toxicants is associated with an aggravated health status of the general population. Involuntary smoking (IS) exposure is one of the main routes to involuntary toxicants exposure. However, few studies have attempted to understand the environmental cadmium exposure by IS exposure in the general, non-smoking population. The purpose of the current study was to examine the relationship between blood cadmium level and IS level according to gender and age. We used the Korea National Health and Nutrition Examination Survey (KNHANES) IV–VI data that included heavy metal and urine cotinine sampling with IS exposure history. The final analysis comprised 3,493 adults (1,231 males and 2,262 females) and 395 adolescents (210 males and 185 females). Linear regression was performed to estimate the association between self-reported IS exposure with urine cotinine level and blood cadmium level in non-smokers with gender and age group stratification. In final regression model, the effect values (B) (standard errors [SE]) between blood cadmium and urine cotinine level in men was 0.0004 (0.0001) and 0.0006 (0.0002) in adults and adolescents, the B (SE) in women was 0.0006 (0.0002) and 0.0016 (0.0006) in adults and adolescents. Our study revealed, for the first time, a significant association between blood cadmium and IS exposure in non-smokers. Greater efforts are needed to improve environmental justices of the general population from IS, considering the severe harmful effects of involuntary exposure to even a low level of cadmium. PMID:28244280

  6. Respiratory health associated with exposure to automobile exhaust. II. Personal NO2 exposure levels according to distance from the roadside.

    PubMed

    Nakai, S; Nitta, H; Maeda, K

    1995-01-01

    We have conducted several studies to investigate the effect of automobile exhaust on respiratory symptoms. This study was designed to explore differences in personal exposure levels among residents of zones located varying distances from trunk roads with heavy traffic in Tokyo. Personal nitrogen dioxide (NO2) concentration levels for residents and NO2 concentrations inside and outside the residences of each study participant were measured during ten seasons over three years. Three residential zones were determined as follows: Zone A was 0-20 m from the roadside; Zone B was 20-150 m; and Zone C, a reference zone, was a residential district in a suburban area. Approximately fifty residents were selected as the subjects of NO2 measurements. Study participants were female, between 40 and 60 years of age, and nonsmokers. All participants used gas cooking stoves with electric ignition. Outdoor NO2 concentrations in Zone A were always the greatest among the three zones during the study periods, and those in Zone C were consistently the lowest. Personal exposure levels in Zone A were generally higher than those in the other zones, and concentrations in Zone C were the lowest during seasons when no indoor heating was used. The highest mean values for personal exposure levels in Zones A, B, and C were 63.4, 61.0, and 55.3 ppb, respectively. In analyses in which participants were stratified by heater type, the mean personal exposure levels in Zone A were the highest and the levels in Zone C were the lowest for participants without unvented heaters; differences of NO2 levels between Zones A and C ranged from 10.0 to 23.9 ppb. When there were no indoor NO2 sources except gas cooking stoves, both indoor and personal levels of NO2 were attributable primarily to motor vehicle exhaust. In contrast, the use of unvented heaters during the heating seasons could cause NO2 exposures comparable to those attributable to motor vehicles.

  7. Re-exposure to the hypobaric hypoxic brain injury of high altitude: plasma S100B levels and the possible effect of acclimatisation on blood-brain barrier dysfunction.

    PubMed

    Winter, C D; Whyte, T; Cardinal, J; Kenny, R; Ballard, E

    2016-04-01

    Hypobaric hypoxic brain injury results in elevated peripheral S100B levels which may relate to blood-brain barrier (BBB) dysfunction. A period of acclimatisation or dexamethasone prevents altitude-related illnesses and this may involve attenuation of BBB compromise. We hypothesised that both treatments would diminish the S100B response (a measure of BBB dysfunction) on re-ascent to the hypobaric hypoxia of high altitude, in comparison to an identical ascent completed 48 h earlier by the same group. Twelve healthy volunteers, six of which were prescribed dexamethasone, ascended Mt Fuji (summit 3700 m) and serial plasma S100B levels measured. The S100B values reduced from a baseline 0.183 µg/l (95 % CI 0.083-0.283) to 0.145 µg/l (95 % CI 0.088-0.202) at high altitude for the dexamethasone group (n = 6) and from 0.147 µg/l (95 % CI 0.022-0.272) to 0.133 µg/l (95 % CI 0.085-0.182) for the non-treated group (n = 6) [not statistically significant (p = 0.43 and p = 0.82) for the treated and non-treated groups respectively]. [These results contrasted with the statistically significant increase during the first ascent, S100B increasing from 0.108 µg/l (95 % CI 0.092-0.125) to 0.216 µg/l (95 % CI 0.165-0.267) at high altitude]. In conclusion, an increase in plasma S100B was not observed in the second ascent and this may relate to the effect of acclimatisation (or hypoxic pre-conditioning) on the BBB. An exercise stimulated elevation of plasma S100B levels was also not observed during the second ascent. The small sample size and wide confidence intervals, however, precludes any statistically significant conclusions and a larger study would be required to confirm these findings.

  8. Association of dental enamel lead levels with risk factors for environmental exposure.

    PubMed

    Olympio, Kelly Polido Kaneshiro; Naozuka, Juliana; Oliveira, Pedro Vitoriano; Cardoso, Maria Regina Alves; Bechara, Etelvino José Henriques; Günther, Wanda Maria Risso

    2010-10-01

    To analyze household risk factors associated with high lead levels in surface dental enamel. A cross-sectional study was conducted with 160 Brazilian adolescents aged 1418 years living in poor neighborhoods in the city of Bauru, southeastern Brazil, from August to December 2008. Body lead concentrations were assessed in surface dental enamel acid-etch microbiopsies. Dental enamel lead levels were measured by graphite furnace atomic absorption spectrometry and phosphorus levels were measured by inductively coupled plasma optical emission spectrometry. The parents answered a questionnaire about their children's potential early (05 years old) exposure to well-known lead sources. Logistic regression was used to identify associations between dental enamel lead levels and each environmental risk factor studied. Social and familial covariables were included in the models. The results suggest that the adolescents studied were exposed to lead sources during their first years of life. Risk factors associated with high dental enamel lead levels were living in or close to a contaminated area (OR = 4.49; 95% CI: 1.69;11.97); and member of the household worked in the manufacturing of paints, paint pigments, ceramics or batteries (OR = 3.43; 95% CI: 1.31;9.00). Home-based use of lead-glazed ceramics, low-quality pirated toys, anticorrosive paint on gates and/or sale of used car batteries (OR = 1.31; 95% CI: 0.56;3.03) and smoking (OR = 1.66; 95% CI: 0.52;5.28) were not found to be associated with high dental enamel lead levels. Surface dental enamel can be used as a marker of past environmental exposure to lead and lead concentrations detected are associated to well-known sources of lead contamination.

  9. Global Projection of Coastal Exposure Associated with Sea-level Rise beyond Tipping Points

    NASA Astrophysics Data System (ADS)

    Tawatari, R.; Miyazaki, C.; Iseri, Y.; Kiguchi, M.; Kanae, S.

    2015-12-01

    Sea-level rise due to global warming becomes a great matter of concern for global coastal area. Additionally, it has reported in fifth report of IPCC (Intergovernmental Panel on Climate Change) that deglaciation of Greenland ice sheet and Antarctic ice sheet would occur rapidly and enhance sea-level rise if temperature passes certain "Tipping point". In terms of projecting damage induced by sea-level rise globally, some previous studies focused on duration until mainly 2100. Furthermore long-term estimations on centuries to millennial climatic response of the ice sheets which are supposed to be triggered within this or next century would be also important to think about future climate and lifestyle in coastal . In this study, I estimated the long term sea-level which take into account the tipping points of Greenland ice sheet (1.4℃) as sum of 4 factors (thermal expansion, glacier and ice cap, Greenland ice sheet, Antarctic ice sheet). The sea-level follows 4 representative concentration pathways up to 3000 obtained through literature reviewing since there were limited available sea-level projections up to 3000. I also estimated a number of affected population lives in coastal area up to 3000 with using the estimated sea-level. The cost for damage, adaptation and mitigation would be also discussed. These estimations would be useful when decision-makers propose policies for construction of dikes and proposing mitigation plans for sustainable future. The result indicates there would be large and relatively rapid increases in both sea-level rise and coastal exposure if global mean temperature passes the tipping point of Greenland ice sheet. However the tipping points, melting rate and timescale of response are highly uncertain and still discussed among experts. Thus more precise and credible information is required for further accurate estimation of long-term sea-level rise and population exposure in the future.

  10. Coastal vertebrate exposure to predicted habitat changes due to sea level rise

    USGS Publications Warehouse

    Hunter, Elizabeth A.; Nibbelink, Nathan P.; Alexander, Clark R.; Barrett, Kyle; Mengak, Lara F.; Guy, Rachel; Moore, Clinton; Cooper, Robert J.

    2015-01-01

    Sea level rise (SLR) may degrade habitat for coastal vertebrates in the Southeastern United States, but it is unclear which groups or species will be most exposed to habitat changes. We assessed 28 coastal Georgia vertebrate species for their exposure to potential habitat changes due to SLR using output from the Sea Level Affecting Marshes Model and information on the species’ fundamental niches. We assessed forecasted habitat change up to the year 2100 using three structural habitat metrics: total area, patch size, and habitat permanence. Almost all of the species (n = 24) experienced negative habitat changes due to SLR as measured by at least one of the metrics. Salt marsh and ocean beach habitats experienced the most change (out of 16 categorical land cover types) across the three metrics and species that used salt marsh extensively (rails and marsh sparrows) were ranked highest for exposure to habitat changes. Species that nested on ocean beaches (Diamondback Terrapins, shorebirds, and terns) were also ranked highly, but their use of other foraging habitats reduced their overall exposure. Future studies on potential effects of SLR on vertebrates in southeastern coastal ecosystems should focus on the relative importance of different habitat types to these species’ foraging and nesting requirements. Our straightforward prioritization approach is applicable to other coastal systems and can provide insight to managers on which species to focus resources, what components of their habitats need to be protected, and which locations in the study area will provide habitat refuges in the face of SLR.

  11. Narrowband Ultraviolet B Exposures Maintain Vitamin D Levels During Winter: A Randomized Controlled Trial.

    PubMed

    Karppinen, Toni; Ala-Houhala, Meri; Ylianttila, Lasse; Kautiainen, Hannu; Viljakainen, Heli; Reunala, Timo; Snellman, Erna

    2016-05-01

    Exposure to solar ultraviolet B radiation during the summer months is the main source of vitamin D (VD) for people living in northern latitudes. The aim of this study was to determine whether artificial narrowband ultraviolet B (NB-UVB) whole-body exposures could maintain VD levels in winter. The intervention group received 2 standard erythema doses (SEDs) of NB-UVB exposures every second week from October 2013 to April 2014. In October 2013 serum 25-hydroxyvitamin D concentrations were 78.3 nmol/l in the intervention group (n = 16) and 76.8 nmol/l in the control group (n = 18). By April 2014 the concentrations had increased by 11.7 nmol/l (p = 0.029) in the intervention group and decreased by 11.1 nmol/l (p = 0.022) in the control group. The baseline VD concentration showed a negative correlation (p = 0.012) with body mass index (BMI). In conclusion, a suberythemal NB-UVB dose of 2 SED every second week maintains and even increases serum VD concentrations during the winter. A high BMI seems to predispose subjects to low levels of VD.

  12. Aircraft noise exposure affects rat behavior, plasma norepinephrine levels, and cell morphology of the temporal lobe.

    PubMed

    Di, Guo-Qing; Zhou, Bing; Li, Zheng-Guang; Lin, Qi-Li

    2011-12-01

    In order to investigate the physiological effects of airport noise exposure on organisms, in this study, we exposed Sprague-Dawley rats in soundproof chambers to previously recorded aircraft-related noise for 65 d. For comparison, we also used unexposed control rats. Noise was arranged according to aircraft flight schedules and was adjusted to its weighted equivalent continuous perceived noise levels (L(WECPN)) of 75 and 80 dB for the two experimental groups. We examined rat behaviors through an open field test and measured the concentrations of plasma norepinephrine (NE) by high performance liquid chromatography-fluorimetric detection (HPLC-FLD). We also examined the morphologies of neurons and synapses in the temporal lobe by transmission electron microscopy (TEM). Our results showed that rats exposed to airport noise of 80 dB had significantly lower line crossing number (P<0.05) and significantly longer center area duration (P<0.05) than control animals. After 29 d of airport noise exposure, the concentration of plasma NE of exposed rats was significantly higher than that of the control group (P<0.05). We also determined that the neuron and synapsis of the temporal lobe of rats showed signs of damage after aircraft noise of 80 dB exposure for 65 d. In conclusion, exposing rats to long-term aircraft noise affects their behaviors, plasma NE levels, and cell morphology of the temporal lobe.

  13. Coastal Vertebrate Exposure to Predicted Habitat Changes Due to Sea Level Rise.

    PubMed

    Hunter, Elizabeth A; Nibbelink, Nathan P; Alexander, Clark R; Barrett, Kyle; Mengak, Lara F; Guy, Rachel K; Moore, Clinton T; Cooper, Robert J

    2015-12-01

    Sea level rise (SLR) may degrade habitat for coastal vertebrates in the Southeastern United States, but it is unclear which groups or species will be most exposed to habitat changes. We assessed 28 coastal Georgia vertebrate species for their exposure to potential habitat changes due to SLR using output from the Sea Level Affecting Marshes Model and information on the species' fundamental niches. We assessed forecasted habitat change up to the year 2100 using three structural habitat metrics: total area, patch size, and habitat permanence. Almost all of the species (n = 24) experienced negative habitat changes due to SLR as measured by at least one of the metrics. Salt marsh and ocean beach habitats experienced the most change (out of 16 categorical land cover types) across the three metrics and species that used salt marsh extensively (rails and marsh sparrows) were ranked highest for exposure to habitat changes. Species that nested on ocean beaches (Diamondback Terrapins, shorebirds, and terns) were also ranked highly, but their use of other foraging habitats reduced their overall exposure. Future studies on potential effects of SLR on vertebrates in southeastern coastal ecosystems should focus on the relative importance of different habitat types to these species' foraging and nesting requirements. Our straightforward prioritization approach is applicable to other coastal systems and can provide insight to managers on which species to focus resources, what components of their habitats need to be protected, and which locations in the study area will provide habitat refuges in the face of SLR.

  14. Aircraft noise exposure affects rat behavior, plasma norepinephrine levels, and cell morphology of the temporal lobe*

    PubMed Central

    Di, Guo-qing; Zhou, Bing; Li, Zheng-guang; Lin, Qi-li

    2011-01-01

    In order to investigate the physiological effects of airport noise exposure on organisms, in this study, we exposed Sprague-Dawley rats in soundproof chambers to previously recorded aircraft-related noise for 65 d. For comparison, we also used unexposed control rats. Noise was arranged according to aircraft flight schedules and was adjusted to its weighted equivalent continuous perceived noise levels (L WECPN) of 75 and 80 dB for the two experimental groups. We examined rat behaviors through an open field test and measured the concentrations of plasma norepinephrine (NE) by high performance liquid chromatography-fluorimetric detection (HPLC-FLD). We also examined the morphologies of neurons and synapses in the temporal lobe by transmission electron microscopy (TEM). Our results showed that rats exposed to airport noise of 80 dB had significantly lower line crossing number (P<0.05) and significantly longer center area duration (P<0.05) than control animals. After 29 d of airport noise exposure, the concentration of plasma NE of exposed rats was significantly higher than that of the control group (P<0.05). We also determined that the neuron and synapsis of the temporal lobe of rats showed signs of damage after aircraft noise of 80 dB exposure for 65 d. In conclusion, exposing rats to long-term aircraft noise affects their behaviors, plasma NE levels, and cell morphology of the temporal lobe. PMID:22135145

  15. Coastal Vertebrate Exposure to Predicted Habitat Changes Due to Sea Level Rise

    NASA Astrophysics Data System (ADS)

    Hunter, Elizabeth A.; Nibbelink, Nathan P.; Alexander, Clark R.; Barrett, Kyle; Mengak, Lara F.; Guy, Rachel K.; Moore, Clinton T.; Cooper, Robert J.

    2015-12-01

    Sea level rise (SLR) may degrade habitat for coastal vertebrates in the Southeastern United States, but it is unclear which groups or species will be most exposed to habitat changes. We assessed 28 coastal Georgia vertebrate species for their exposure to potential habitat changes due to SLR using output from the Sea Level Affecting Marshes Model and information on the species' fundamental niches. We assessed forecasted habitat change up to the year 2100 using three structural habitat metrics: total area, patch size, and habitat permanence. Almost all of the species ( n = 24) experienced negative habitat changes due to SLR as measured by at least one of the metrics. Salt marsh and ocean beach habitats experienced the most change (out of 16 categorical land cover types) across the three metrics and species that used salt marsh extensively (rails and marsh sparrows) were ranked highest for exposure to habitat changes. Species that nested on ocean beaches (Diamondback Terrapins, shorebirds, and terns) were also ranked highly, but their use of other foraging habitats reduced their overall exposure. Future studies on potential effects of SLR on vertebrates in southeastern coastal ecosystems should focus on the relative importance of different habitat types to these species' foraging and nesting requirements. Our straightforward prioritization approach is applicable to other coastal systems and can provide insight to managers on which species to focus resources, what components of their habitats need to be protected, and which locations in the study area will provide habitat refuges in the face of SLR.

  16. Towards a street-level pollen concentration and exposure forecast

    NASA Astrophysics Data System (ADS)

    van der Molen, Michiel; Krol, Maarten; van Vliet, Arnold; Heuvelink, Gerard

    2015-04-01

    Atmospheric pollen are an increasing source of nuisance for people in industrialised countries and are associated with significant cost of medication and sick leave. Citizen pollen warnings are often based on emission mapping based on local temperature sum approaches or on long-range atmospheric model approaches. In practise, locally observed pollen may originate from both local sources (plants in streets and gardens) and from long-range transport. We argue that making this distinction is relevant because the diurnal and spatial variation in pollen concentrations is much larger for pollen from local sources than for pollen from long-range transport due to boundary layer processes. This may have an important impact on exposure of citizens to pollen and on mitigation strategies. However, little is known about the partitioning of pollen into local and long-range origin categories. Our objective is to study how the concentrations of pollen from different sources vary temporally and spatially, and how the source region influences exposure and mitigation strategies. We built a Hay Fever Forecast system (HFF) based on WRF-chem, Allergieradar.nl, and geo-statistical downscaling techniques. HFF distinguishes between local (individual trees) and regional sources (based on tree distribution maps). We show first results on how the diurnal variation of pollen concentrations depends on source proximity. Ultimately, we will compare the model with local pollen counts, patient nuisance scores and medicine use.

  17. Hydroxyl radicals cause fluctuation in intracellular ferrous ion levels upon light exposure during photoreceptor cell death.

    PubMed

    Imamura, Tomoyo; Hirayama, Tasuku; Tsuruma, Kazuhiro; Shimazawa, Masamitsu; Nagasawa, Hideko; Hara, Hideaki

    2014-12-01

    Iron accumulation is a potential pathogenic event often seen in age-related macular degeneration (AMD) patients. In this study, we focused on the relationship between AMD pathology and concentrations of ferrous ion, which is a highly reactive oxygen generator in biological systems. Murine cone-cells-derived 661 W cells were exposed to white fluorescence light at 2500 lx for 1, 3, 6, or 12 h. Levels of ferrous ions, reactive oxygen species (ROS), and hydroxyl radicals were detected by RhoNox-1, a novel fluorescent probe for the selective detection of ferrous ion, 5-(and-6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate, acetyl ester (CM-H2DCFDA), and 3'-p-(aminophenyl) fluorescein, respectively. Reduced glutathione, total iron levels and photoreceptor cell death were also measured. Two genes related to iron metabolism, transferrin receptor 1 (TfR1) and H ferritin (HFt), were quantified by RT-PCR. The effects of ferrous ion on cell death and hydroxyl radical production were determined by treatment with a ferrous ion chelating agent, 2,2'-bipyridyl. We found that the ferrous ion level decreased with light exposure in the short time frame, whereas it was upregulated during a 6-h light exposure. Total iron, ROS, cell death rate, and expression of TfR and HFt genes were significantly increased in a time-dependent manner in 661 W cells exposed to light. Chelation with 2,2'-bipyridyl reduced the level of hydroxyl radicals and protected against light-induced cell death. These results suggest that light exposure decreases ferrous ion levels and enhances iron uptake in photoreceptor cells. Ferrous ion may be involved in light-induced photoreceptor cell death through production of hydroxyl radicals. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Salivary cortisol levels are elevated in the afternoon and at bedtime in children with prenatal alcohol exposure.

    PubMed

    Keiver, Kathy; Bertram, Chris P; Orr, Alison Pritchard; Clarren, Sterling

    2015-02-01

    Prenatal alcohol exposure can cause dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, which may underlie some of the behavioral and adaptive problems seen in individuals with Fetal Alcohol Spectrum Disorders (FASD). Infants prenatally exposed to alcohol show altered basal and post-stress cortisol levels, but it is unknown if this persists beyond 2 years of age. It is also unknown if cortisol levels can be normalized through intervention programs. In this study, we investigated the effects of a physical activity program for children with FASD to determine: 1) if HPA dysregulation persists in school-age children with FASD, and 2) the effect of our program on cortisol levels. Twenty six children (ages 6-14 years) with FASD participated in an 8 week motor skill development program. Salivary cortisol levels were measured in 24 children and compared at 4 time points: before, immediately after, 3 months, and 1 year after program completion. Cortisol levels were also compared to 32 control children to evaluate the long-term effects of prenatal alcohol exposure on HPA regulation. For each time point, saliva was collected on each of 2 days at 3 times in the diurnal cycle: awakening, after school, and just before bedtime. Cortisol levels were significantly higher in the afternoon and at bedtime in children with FASD with confirmed prenatal exposure to high levels of alcohol (alcohol exposure rank 4), compared with Control children or children with FASD with exposure to low or unknown levels of alcohol (alcohol exposure rank 3). The program did not significantly affect cortisol levels in children with FASD as a group. These results provide support for long-term effects of prenatal alcohol exposure on the HPA system in humans, which could increase vulnerability to mental health issues and diseases later in life. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. Secondhand smoke exposure and serum cotinine levels among current smokers in the USA.

    PubMed

    Lindsay, Ryan P; Tsoh, Janice Y; Sung, Hai-Yen; Max, Wendy

    2016-03-01

    Secondhand smoke (SHS) likely provides additional exposure to nicotine and toxins for smokers, but has been understudied. Our objective was to determine whether SHS exposure among smokers yields detectable differences in cotinine levels compared with unexposed smokers at the population level. Using the US National Health and Nutrition Examination Survey (NHANES) for the years 1999-2012, we compared serum cotinine levels of 4547 current adult cigarette smokers stratified by self-reported SHS exposure sources (home and/or work) and smoking intensity. A weighted multivariable linear regression model determined the association between SHS exposure and cotinine levels among smokers. Smokers with SHS exposure at home (43.8%) had higher cotinine levels (β=0.483, p≤0.001) compared with those with no SHS exposure at home after controlling for the number of cigarettes smoked per day and number of days smoked in the previous 5 days, survey year, age, gender and education. Smokers with SHS exposure at work (20.0%) did not have significantly higher cotinine levels after adjustment. The adjusted geometric mean cotinine levels of light smokers (1-9 cigarettes per day) with no SHS exposure, exposure at work only, home only, and both home and work were 52.0, 62.7, 67.2, 74.4 ng/mL, respectively, compared with 219.4, 220.9, 255.2, 250.5 ng/mL among moderate/heavy smokers (≥10 cigarettes per day). Smokers living in residences where others smoke inside the home had significantly higher cotinine levels than smokers reporting no SHS exposure, regardless of individual smoking intensity. Future research should target the role that SHS exposure may have in nicotine dependence, cessation outcomes and other health impacts among smokers. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  20. Association between Blood Dioxin Level and Chronic Kidney Disease in an Endemic Area of Exposure

    PubMed Central

    Huang, Chien-Yuan; Wu, Cheng-Long; Wu, Jin-Shang; Chang, Jung-Wei; Cheng, Ya-Yun; Kuo, Yau-Chang; Yang, Yi-Ching

    2016-01-01

    Background Dioxin is an industrial pollutant related to various diseases, but epidemiological data on its effects on the kidney are limited. Therefore, we conducted a study to evaluate the association between dioxin exposure and chronic kidney disease (CKD) and identify the related factors. Methods We conducted a community-based cross-sectional study and recruited participants from an area where the residents were exposed to dioxin released from a factory. We defined a “high dioxin level” as polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) ≥ 20 pg WHO98-TEQDF/g lipid in the serum and defined CKD as having an estimated glomerular filtration rate (e-GFR) ≤ 60 mL/min/1.73m2 or a diagnosis of CKD by a physician. The renal function was assessed between 2005 and 2010, and we excluded those who had had kidney diseases before the study started. Comparisons between patients of CKD and those who did not have CKD were made to identify the risk factors for CKD. Results Of the 2898 participants, 1427 had high dioxin levels, and 156 had CKD. In the univariate analyses, CKD was associated with high dioxin levels, age, gender, metabolic syndrome, diabetes mellitus, hypertension, and high insulin and uric acid levels. After adjusting for other factors, we found high dioxin levels (adjusted odds ratio [AOR] = 1.76, 95% confidence interval [CI]: 1.04–2.99), female gender (AOR = 1.74, 95%CI: 1.20–2.53), hypertension (AOR = 1.68, 95%CI: 1.17–2.42), high insulin levels (AOR = 2.14, 95% CI: 1.26–3.61), high uric acid levels (AOR = 4.25, 95% CI: 2.92–6.20), and older age (AOR = 4.66, 95% CI: 1.87–11.62 for 40–64 year and AOR = 26.66, 95% CI: 10.51–67.62 for age ≥ 65 year) were independent predictors of CKD. Conclusion A high dioxin level was associated with an increased prevalence of CKD. Therefore, the kidney function of populations with exposure to dioxin should be monitored. PMID:26963719

  1. Determinations of personal carbon monoxide exposure and blood carboxyhemoglobin levels in Korea.

    PubMed

    Chung, Y; Park, S E; Lee, K; Yanagisawa, Y; Spengler, J D

    1994-12-01

    Determinant factors for personal carbon monoxide (CO) exposures were sought in Korea, where CO poisoning has been a major public health problem due to coal briquette (Yeontan) combustion for space heating and cooking. Personal 24-hr CO exposures of 15 housewives were measured by CO passive samplers on 2 days of the week (Wednesday and Sunday). Blood samples were taken to measure carboxyhemoglobin (COHb) just after the exposure sampling. Average CO exposure and COHb level were 5.6 ppm and 2.4%, respectively. Personal CO exposures as well as COHb levels were significantly increased by the use of Yeontan, especially on a weekday. Carboxyhemoglobin levels were closely related to the time between blood collection and replacement of Yeontan: the closer the blood collection was to replace Yeontan, the higher the COHb levels were. Assuming a background COHb of 1.34%, COHb increased on average by 1.8% with a 24-hr personal CO exposure of 10 ppm. The relationship between CO exposure and COHb level was provided by simultaneous direct measurements in real environment, although a measurement of COHb at the end of exposure could not represent previous 24-hr exposure thoroughly.

  2. The Revised Electromagnetic Fields Directive and Worker Exposure in Environments With High Magnetic Flux Densities

    PubMed Central

    Stam, Rianne

    2014-01-01

    Some of the strongest electromagnetic fields (EMF) are found in the workplace. A European Directive sets limits to workers’ exposure to EMF. This review summarizes its origin and contents and compares magnetic field exposure levels in high-risk workplaces with the limits set in the revised Directive. Pubmed, Scopus, grey literature databases, and websites of organizations involved in occupational exposure measurements were searched. The focus was on EMF with frequencies up to 10 MHz, which can cause stimulation of the nervous system. Selected studies had to provide individual maximum exposure levels at the workplace, either in terms of the external magnetic field strength or flux density or as induced electric field strength or current density. Indicative action levels and the corresponding exposure limit values for magnetic fields in the revised European Directive will be higher than those in the previous version. Nevertheless, magnetic flux densities in excess of the action levels for peripheral nerve stimulation are reported for workers involved in welding, induction heating, transcranial magnetic stimulation, and magnetic resonance imaging (MRI). The corresponding health effects exposure limit values for the electric fields in the worker’s body can be exceeded for welding and MRI, but calculations for induction heating and transcranial magnetic stimulation are lacking. Since the revised European Directive conditionally exempts MRI-related activities from the exposure limits, measures to reduce exposure may be necessary for welding, induction heating, and transcranial nerve stimulation. Since such measures can be complicated, there is a clear need for exposure databases for different workplace scenarios with significant EMF exposure and guidance on good practices. PMID:24557933

  3. The revised electromagnetic fields directive and worker exposure in environments with high magnetic flux densities.

    PubMed

    Stam, Rianne

    2014-06-01

    Some of the strongest electromagnetic fields (EMF) are found in the workplace. A European Directive sets limits to workers' exposure to EMF. This review summarizes its origin and contents and compares magnetic field exposure levels in high-risk workplaces with the limits set in the revised Directive. Pubmed, Scopus, grey literature databases, and websites of organizations involved in occupational exposure measurements were searched. The focus was on EMF with frequencies up to 10 MHz, which can cause stimulation of the nervous system. Selected studies had to provide individual maximum exposure levels at the workplace, either in terms of the external magnetic field strength or flux density or as induced electric field strength or current density. Indicative action levels and the corresponding exposure limit values for magnetic fields in the revised European Directive will be higher than those in the previous version. Nevertheless, magnetic flux densities in excess of the action levels for peripheral nerve stimulation are reported for workers involved in welding, induction heating, transcranial magnetic stimulation, and magnetic resonance imaging (MRI). The corresponding health effects exposure limit values for the electric fields in the worker's body can be exceeded for welding and MRI, but calculations for induction heating and transcranial magnetic stimulation are lacking. Since the revised European Directive conditionally exempts MRI-related activities from the exposure limits, measures to reduce exposure may be necessary for welding, induction heating, and transcranial nerve stimulation. Since such measures can be complicated, there is a clear need for exposure databases for different workplace scenarios with significant EMF exposure and guidance on good practices.

  4. Rapid infection of pigs following exposure to environments contaminated with different levels of Salmonella typhimurium.

    PubMed

    Boughton, Claire; Egan, John; Kelly, Gabrielle; Markey, Bryan; Leonard, Nola

    2007-01-01

    Pigs reared in an environment free of Salmonella species or on farms with low levels of infection may acquire infection during transport to the abattoir or while held in lairage. We designed a study to determine if pigs could become infected with S. Typhimurium when placed in a contaminated environment similar to that observed in commercial lairage. In addition, quantitative examination of salmonellae in all environmental and animal samples was undertaken. In order to simulate a naturally contaminated environment, animals experimentally infected with a challenge strain of S. Typhimurium (PT12) were used to seed the trial pen environment with salmonellae. In trial 1, pigs were exposed to a highly contaminated environment (5.4 log(10) CFU/100 cm(2)) for 2, 3, or 24 hours. Following these exposure periods, pigs were euthanized and samples including gastrointestinal and associated lymphoid tissue were analyzed for the challenge strain. S. Typhimuirum PT12 was detected in at least one sample type analyzed from each pig after exposure for > or =2 hours. The most frequently contaminated samples were tonsils (100% positive), followed by segments of the ileocecal junction (94.4% positive) and cecal contents (89% positive). Quantitative analysis conducted on cecal contents and ilocaecal junction segments revealed that similar numbers of organisms (1.1-2 log (10) /g) were isolated at all timepoints. In trial 2, pigs were exposed to a less contaminated environment (2.65 log (10) CFU/100 cm(2)) for periods of 1, 3, 6, or 24 hours. S. Typhimuirum PT12 was not detected in any sample from pigs euthanized after exposure of 1 hour. The challenge strain was recovered from the cecal contents of pigs after exposures of 3, 6, and 24 hours, and from the tonsil of one pig after exposure for 6 hours. These results highlight the need to reduce the environmental load of Salmonella spp. in lairage holding pens in order to reduce the numbers of infected pigs entering the slaughter process.

  5. High throughput illumination systems for solar simulators and photoresist exposure

    NASA Astrophysics Data System (ADS)

    Feldman, Arkady

    2010-08-01

    High throughput illumination systems are critical component in photolithography, solar simulators, UV curing, microscopy, and spectral analysis. A good refractive condenser system has F/# .60, or N.A .80, but it captures only 10 to 15% of energy emitted by an incandescent or gas-discharge lamp, as these sources emit light in all directions. Systems with ellipsoidal or parabolic reflectors are much more efficient, they capture up to 80% of total energy emitted by lamps. However, these reflectors have large aberrations when working with real sources of finite dimensions, resulting in poor light concentrating capability. These aberrations also increase beam divergence, collimation, and affect edge definition in flood exposure systems. The problem is aggravated by the geometry of high power Arc lamps where, for thermal considerations, the anode has a larger diameter than the cathode and absorbs and obscures part of the energy. This results in an asymmetrical energy distribution emitted by the lamp and makes efficiency of Lamp - reflector configuration dependent on orientation of lamp in the reflector. This paper presents the analysis of different configurations of Lamp - Reflector systems of different power levels and their energy distribution in the image plane. Configuration, which results in significant improvement of brightness, is derived.

  6. Elevated Blood Lead Levels in Infants and Mothers in Benin and Potential Sources of Exposure

    PubMed Central

    Bodeau-Livinec, Florence; Glorennec, Philippe; Cot, Michel; Dumas, Pierre; Durand, Séverine; Massougbodji, Achille; Ayotte, Pierre; Le Bot, Barbara

    2016-01-01

    Lead in childhood is well known to be associated with poor neurodevelopment. As part of a study on maternal anemia and offspring neurodevelopment, we analyzed blood lead level (BLL) with no prior knowledge of lead exposure in 225 mothers and 685 offspring 1 to 2 years old from Allada, a semi-rural area in Benin, sub-Saharan Africa, between May 2011 and May 2013. Blood samples were analyzed by inductively coupled plasma mass spectrometry. Environmental assessments in households and isotopic ratio measurements were performed for eight children with BLL > 100 µg/L. High lead levels (BLL > 50 µg/L) were found in 44% of mothers and 58% of children. The median BLL was 55.1 (interquartile range 39.2–85.0) and 46.6 (36.5–60.1) µg/L, respectively. Maternal BLL was associated with offspring’s consumption of piped water and animals killed by ammunition. Children’s BLL was associated with presence of paint chips in the house and consumption of animals killed by ammunition. In this population, with 98% of children still breastfed, children’s BLL was highly associated with maternal BLL on multivariate analyses. Environmental measures and isotopic ratios supported these findings. Offspring may be highly exposed to lead in utero and probably via breastfeeding in addition to lead paint exposure. PMID:26978384

  7. Elevated Blood Lead Levels in Infants and Mothers in Benin and Potential Sources of Exposure.

    PubMed

    Bodeau-Livinec, Florence; Glorennec, Philippe; Cot, Michel; Dumas, Pierre; Durand, Séverine; Massougbodji, Achille; Ayotte, Pierre; Le Bot, Barbara

    2016-03-11

    Lead in childhood is well known to be associated with poor neurodevelopment. As part of a study on maternal anemia and offspring neurodevelopment, we analyzed blood lead level (BLL) with no prior knowledge of lead exposure in 225 mothers and 685 offspring 1 to 2 years old from Allada, a semi-rural area in Benin, sub-Saharan Africa, between May 2011 and May 2013. Blood samples were analyzed by inductively coupled plasma mass spectrometry. Environmental assessments in households and isotopic ratio measurements were performed for eight children with BLL > 100 µg/L. High lead levels (BLL > 50 µg/L) were found in 44% of mothers and 58% of children. The median BLL was 55.1 (interquartile range 39.2-85.0) and 46.6 (36.5-60.1) µg/L, respectively. Maternal BLL was associated with offspring's consumption of piped water and animals killed by ammunition. Children's BLL was associated with presence of paint chips in the house and consumption of animals killed by ammunition. In this population, with 98% of children still breastfed, children's BLL was highly associated with maternal BLL on multivariate analyses. Environmental measures and isotopic ratios supported these findings. Offspring may be highly exposed to lead in utero and probably via breastfeeding in addition to lead paint exposure.

  8. Chronic low-level hydrogen sulfide exposure and potential effects on human health: a review of the epidemiological evidence.

    PubMed

    Lewis, R Jeffrey; Copley, G Bruce

    2015-02-01

    The effects of exposure to high concentrations of hydrogen sulfide (H2S) on human health are well known. However, the potential human health hazards posed by low-level chronic environmental H2S exposure are being debated. Accordingly, we reviewed the literature regarding the effects of chronic, environmentally-relevant H2S exposures on human health. All human observational studies using an analytical study design (e.g. cohort, cross-sectional, case-control) to evaluate chronic-duration low-level H2S exposure (approximately ≤ 10 ppm on average, for 1 year or more), were evaluated for a range of health outcomes. Respiratory symptoms in both adults and children were the most consistently reported symptoms on the increase. When reported, such effects appear to be temporary, given that there is no consistent evidence of pulmonary function deficit in either age group, among those chronically exposed to low H2S concentrations. While sparse, some data also suggest potential ocular symptoms and disorders associated with chronic ambient level H2S exposure in adults (not children), but the limited data on H2S exposures, co-exposures and/or strong odor stimulus of H2S, temper interpretation. Neurological symptoms and deficits have been reported in some studies, but the highest quality evidence, obtained using objective outcome measures and a reasonably detailed assessment of exposure, does not support a neurological-related risk in adults (only one study in children). For the other endpoints assessed (cardiovascular, reproductive and developmental, and carcinogenicity), the results were mixed and/or conflicting, but did not indicate a potential health hazard, although this literature has several major limitations, particularly with regard to exposure estimation and the ability to assess exposure-response.

  9. The relationship between low-level benzene exposure and leukemia in Canadian petroleum distribution workers

    SciTech Connect

    Schnatter, A.R.; Armstrong, T.W.; Nicolich, M.J.

    1996-12-01

    This study was conducted to evaluate the relationship between leukemia occurrence and long-term, low-level benzene exposures in petroleum distribution workers. Fourteen cases were identified among a previously studied cohort. Four controls per case were selected from the same cohort, controlling for birth year and time at risk. Industrial hygienists estimated workplace exposures for benzene, without knowledge of case-control status. Average benzene concentrations ranged from 0.01 to 6.2 ppm. Company medical records were used to abstract information on other potential confounders such as cigarette smoking. Odds ratios were calculated for several exposure metrics. Conditional logistic regression modeling was used to control for potential confounders. The risk of leukemia was not associated with increasing cumulative exposure to benzene for these exposure levels. Duration of benzene exposure was more closely associated with leukemia risk than other exposure metrics, although results were not statistically significant. A family history of cancer and cigarette smoking were the two strongest risk factors for leukemia, with cumulative benzene exposure showing no additional risk when considered in the same models. This study is consistent with other data in that it was unable to demonstrate a relationship between leukemia and long-term, low-level benzene exposures. The power of the study was limited. Thus, further study on benzene exposures in this concentration range are warranted. 20 refs., 1 fig., 6 tabs.

  10. Low-level exposure to lead, blood pressure, and hypertension in a population-based cohort.

    PubMed

    Gambelunghe, Angela; Sallsten, Gerd; Borné, Yan; Forsgard, Niklas; Hedblad, Bo; Nilsson, Peter; Fagerberg, Björn; Engström, Gunnar; Barregard, Lars

    2016-08-01

    Environmental lead exposure is a possible causative factor for increased blood pressure and hypertension, but large studies at low-level exposure are scarce, and results inconsistent. We aimed to examine the effects of environmental exposure to lead in a large population-based sample. We assessed associations between blood lead and systolic/diastolic blood pressure and hypertension in 4452 individuals (46-67 years) living in Malmö, Sweden, in 1991-1994. Blood pressure was measured using a mercury sphygmomanometer after 10min supine rest. Hypertension was defined as high systolic (≥140mmHg) or diastolic (≥90mmHg) blood pressure and/or current use of antihypertensive medication. Blood lead was calculated from lead in erythrocytes and haematocrit. Multivariable associations between blood lead and blood pressure or hypertension were assessed by linear and logistic regression. Two-thirds of the cohort was re-examined 16 years later. At baseline, mean blood pressure was 141/87mmHg, 16% used antihypertensive medication, 63% had hypertension, and mean blood lead was 28µg/L. Blood lead in the fourth quartile was associated with significantly higher systolic and diastolic blood pressure (point estimates: 1-2mmHg) and increased prevalence of hypertension (odds ratio: 1.3, 95% confidence interval: 1.1-1.5) versus the other quartiles after adjustment for sex, age, smoking, alcohol, waist circumference, and education. Associations were also significant with blood lead as a continuous variable. Blood lead at baseline, having a half-life of about one month, was not associated with antihypertensive treatment at the 16-year follow-up. Low-level lead exposure increases blood pressure and may increase the risk of hypertension. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  11. The Effect of DEM Quality on Sea Level Rise Exposure Analysis

    NASA Astrophysics Data System (ADS)

    Kulp, S. A.; Strauss, B.

    2015-12-01

    Sea level rise (SLR) caused by climate change could cause significant disruptions in coastal communities across the world. Current projections estimate that we may see in the vicinity of 1 meter of SLR by the end of the century, and due to collapsing ice sheets in West Antarctica, more than 3 meters of global SLR appear very likely in the long run. It is therefore crucial that we begin to accurately understand both the short- and long-term effects this level of flooding could have on each country's land area and population. However, while we have high-resolution digital elevation models (DEMs) publicly available for some parts of the world, such as the coastal lidar datasets distributed by NOAA for the US, most of the rest of the world is only covered by much poorer-quality data, such as data from SRTM (3 arcsec, or roughly 90m, horizontal resolution). In this work, we perform SLR analysis using both NOAA lidar- and SRTM-derived DEMs in the United States, in order to understand how using low-quality DEMs affect the final analysis results. We find that in many states, the computed population exposure at 1 meter SLR is over 2x higher when using the Lidar DEM, compared to the results computed from SRTM. In addition to the clear differences in horizontal resolution, this very large difference in computed exposure could likely be explained by the fact that SRTM is based on surface elevation, while the Lidar DEM is based on bare earth elevation. We therefore conclude that any worldwide SLR analysis using SRTM would produce exposure estimates that are far too low, and higher-quality global DEMs are necessary in order to generate exposure analysis of reasonable accuracy.

  12. Mercury exposure in French Guiana: Levels and determinants

    SciTech Connect

    Cordier, S.; Mandereau, L.; Grasmick, C.; Paquier-Passelaigue, M.; Weber, J.P.; Jouan, M.

    1998-07-01

    Mercury is used widely for gold extraction in French Guiana and throughout the entire Amazon basin. To evaluate contamination among the general population, the authors chose individuals who attended 13 health centers and maternity hospitals dispersed geographically across the territory and served Guiana`s different populations. Five hundred individuals (109 pregnant women, 255 other adults, and 136 children) who received care at one of the centers were selected randomly for this study. Each individual answered a questionnaire and provided a hair sample. The authors determined mercury in hair with atomic absorption spectrometry. The following mean levels of mercury were observed: 1.6 {micro}g/g among pregnant women; 3.4 {micro}g/g among other adults; and 2.5 {micro}g/g among children. Diet factors contributed the most to mercury levels, especially consumption of freshwater fish and livers from game. Other factors, including age, dental amalgams, use of skin-lightening cosmetics, and residence near a gold-mining community, did not contribute significantly to mercury levels. Overall, 12% of the samples contained mercury levels in excess of 10 {micro}g/g, but in some Amerindian communities up to 79% of the children had hair mercury levels that exceeded 10 {micro}g/g. The results of this study indicated that (a) diet played a predominant role in total mercury burden, and (b) in some communities, mercury contamination exceeded safe levels.

  13. Biomonitoring occupational sevoflurane exposure at low levels by urinary sevoflurane and hexafluoroisopropanol.

    PubMed

    Scapellato, Maria Luisa; Carrieri, Mariella; Maccà, Isabella; Salamon, Fabiola; Trevisan, Andrea; Manno, Maurizio; Bartolucci, Giovanni Battista

    2014-12-01

    This study aimed to correlate environmental sevoflurane levels with urinary concentrations of sevoflurane (Sev-U) or its metabolite hexafluoroisopropanol (HFIP) in order to assess and discuss the main issues relating to which biomarker of sevoflurane exposure is best, and possibly suggest the corresponding biological equivalent exposure limit values. Individual sevoflurane exposure was measured in 100 healthcare operators at five hospitals in north-east Italy using the passive air sampling device Radiello(®), and assaying Sev-U and HFIP concentrations in their urine collected at the end of the operating room session. All analyses were performed by gas chromatography-mass spectrometry. Environmental sevoflurane levels in the operating rooms were also monitored continuously using an infrared photoacoustic analyzer. Our results showed very low individual sevoflurane exposure levels, generally below 0.5 ppm (mean 0.116 ppm; range 0.007-0.940 ppm). Sev-U and HFIP concentrations were in the range of 0.1-17.28 μg/L and 5-550 μg/L, respectively. Both biomarkers showed a statistically significant correlation with the environmental exposure levels (Sev-U, r=0.49; HFIP, r=0.52), albeit showing fairly scattered values. Sev-U values seem to be influenced by peaks of exposure, especially at the end of the operating-room session, whereas HFIP levels by exposure on the previous day, the data being consistent with the biomarkers' very different half-lives (2.8 and 19 h, respectively). According to our results, both Sev-U and HFIP are appropriate biomarkers for assessing sevoflurane exposure at low levels, although with some differences in times/patterns of exposure. More work is needed to identify the best biomarker of sevoflurane exposure and the corresponding biological equivalent exposure limit values.

  14. DPOAE level mapping for detecting noise-induced cochlear damage from short-duration music exposures.

    PubMed

    Buckey, Jay C; Fellows, Abigail M; Clavier, Odile H; Allen, Lindsay V; Brooks, Chris A; Norris, Jesse A; Gui, Jiang; Meinke, Deanna K

    2015-01-01

    Distortion product otoacoustic emission (DPOAE) level mapping provides a comprehensive picture of cochlear responses over a range of DP frequencies and f₂/f₁ratios. We hypothesized that individuals exposed to high-level sound would show changes detectable by DPOAE mapping, but not apparent on a standard DP-gram. Thirteen normal hearing subjects were studied before and after attending music concerts. Pure-tone audiometry (500-8,000 Hz), DP-grams (0.3-10 kHz) at 1.22 ratio, and DPOAE level maps were collected prior to, as soon as possible after, and the day after the concerts. All maps covered the range of 2,000-6,000 Hz in DP frequency and from 1.3 to -1.3 in ratio using equi-level primary tone stimuli. Changes in the pure-tone audiogram were significant (P ≤ 0.01) immediately after the concert at 1,000 Hz, 4,000 Hz, and 6,000 Hz. The DP-gram showed significant differences only at f₂= 4,066 (P = 0.01) and f₂= 4,348 (P = 0.04). The postconcert changes were readily apparent both visually and statistically (P ≤ 0.01) on the mean DP level maps, and remained statistically significantly different from baseline the day after noise exposure although no significant changes from baseline were seen on the DP-gram or audiogram the day after exposure. Although both the DP-gram and audiogram showed recovery by the next day, the average DPOAE level maps remained significantly different from baseline. The mapping data showed changes in the cochlea that were not detected from the DP-gram obtained at a single ratio. DPOAE level mapping provides comprehensive information on subtle cochlear responses, which may offer advantages for studying and tracking noise-induced hearing loss (NIHL).

  15. Pesticide Exposure Alters Follicle-Stimulating Hormone Levels in Mexican Agricultural Workers

    PubMed Central

    Recio, Rogelio; Ocampo-Gómez, Guadalupe; Morán-Martínez, Javier; Borja-Aburto, Victor; López-Cervantes, Malaquías; Uribe, Marisela; Torres-Sánchez, Luisa; Cebrián, Mariano E.

    2005-01-01

    Organophosphorous pesticides (OPs) are suspected of altering reproductive function by reducing brain acetylcholinesterase activity and monoamine levels, thus impairing hypothalamic and/or pituitary endocrine functions and gonadal processes. Our objective was to evaluate in a longitudinal study the association between OP exposure and serum levels of pituitary and sex hormones. Urinary OP metabolite levels were measured by gas–liquid chromatography, and serum pituitary and sex hormone levels by enzymatic immunoassay and radioimmunoassay in 64 men. A total of 147 urine and blood samples were analyzed for each parameter. More than 80% of the participants had at least one OP metabolite in their urine samples. The most frequent metabolite found was diethylthiophosphate (DETP; 55%), followed by diethylphosphate (DEP; 46%), dimethylthiophosphate (DMTP; 32%), and dimethyldithiophosphate (DMDTP; 31%). However, the metabolites detected at higher concentrations were DMTP, DEP, DMDTP, and dimethylphosphate. There was a high proportion of individuals with follicle-stimulating hormone (FSH) concentrations outside the range of normality (48%). The average FSH serum levels were higher during the heavy pesticide spraying season. However, a multivariate analysis of data collected in all periods showed that serum FSH levels were negatively associated with urinary concentrations of both DMTP and DMDTP, whereas luteinizing hormone (LH) was negatively associated with DMTP. We observed no significant associations between estradiol or testosterone serum levels with OP metabolites. The hormonal disruption in agricultural workers presented here, together with results from experimental animal studies, suggests that OP exposure disrupts the hypothalamic–pituitary endocrine function and also indicates that FSH and LH are the hormones most affected. PMID:16140621

  16. DPOAE level mapping for detecting noise-induced cochlear damage from short-duration music exposures

    PubMed Central

    Buckey, Jay C.; Fellows, Abigail M.; Clavier, Odile H.; Allen, Lindsay V.; Brooks, Chris A.; Norris, Jesse A.; Gui, Jiang; Meinke, Deanna K.

    2015-01-01

    Distortion product otoacoustic emission (DPOAE) level mapping provides a comprehensive picture of cochlear responses over a range of DP frequencies and f2/f1 ratios. We hypothesized that individuals exposed to high-level sound would show changes detectable by DPOAE mapping, but not apparent on a standard DP-gram. Thirteen normal hearing subjects were studied before and after attending music concerts. Pure-tone audiometry (500-8,000 Hz), DP-grams (0.3-10 kHz) at 1.22 ratio, and DPOAE level maps were collected prior to, as soon as possible after, and the day after the concerts. All maps covered the range of 2,000-6,000 Hz in DP frequency and from 1.3 to -1.3 in ratio using equi-level primary tone stimuli. Changes in the pure-tone audiogram were significant (P ≤ 0.01) immediately after the concert at 1,000 Hz, 4,000 Hz, and 6,000 Hz. The DP-gram showed significant differences only at f2 = 4,066 (P = 0.01) and f2 = 4,348 (P = 0.04). The postconcert changes were readily apparent both visually and statistically (P ≤ 0.01) on the mean DP level maps, and remained statistically significantly different from baseline the day after noise exposure although no significant changes from baseline were seen on the DP-gram or audiogram the day after exposure. Although both the DP-gram and audiogram showed recovery by the next day, the average DPOAE level maps remained significantly different from baseline. The mapping data showed changes in the cochlea that were not detected from the DP-gram obtained at a single ratio. DPOAE level mapping provides comprehensive information on subtle cochlear responses, which may offer advantages for studying and tracking noise-induced hearing loss (NIHL). PMID:26356368

  17. Comparison of Highly Resolved Model-Based Exposure ...

    EPA Pesticide Factsheets

    Human exposure to air pollution in many studies is represented by ambient concentrations from space-time kriging of observed values. Space-time kriging techniques based on a limited number of ambient monitors may fail to capture the concentration from local sources. Further, because people spend more time indoors, using ambient concentration to represent exposure may cause error. To quantify the associated exposure error, we computed a series of six different hourly-based exposure metrics at 16,095 Census blocks of three Counties in North Carolina for CO, NOx, PM2.5, and elemental carbon (EC) during 2012. These metrics include ambient background concentration from space-time ordinary kriging (STOK), ambient on-road concentration from the Research LINE source dispersion model (R-LINE), a hybrid concentration combining STOK and R-LINE, and their associated indoor concentrations from an indoor infiltration mass balance model. Using a hybrid-based indoor concentration as the standard, the comparison showed that outdoor STOK metrics yielded large error at both population (67% to 93%) and individual level (average bias between −10% to 95%). For pollutants with significant contribution from on-road emission (EC and NOx), the on-road based indoor metric performs the best at the population level (error less than 52%). At the individual level, however, the STOK-based indoor concentration performs the best (average bias below 30%). For PM2.5, due to the relatively low co

  18. Association between multi-level inorganic arsenic exposure from drinking water and skin lesions in China.

    PubMed

    Guo, Xiaojuan; Fujino, Yoshihisa; Ye, Xiaolei; Liu, Jun; Yoshimura, Takesumi

    2006-09-01

    Arsenic is one of the most important toxicants in the environment. In Inner Mongolia of China, 300,000 residents are believed to be drinking water containing >50 microg/liter. Skin lesions have been known as the most common consequences resulting from chronic exposure to arsenic. To clarify the prevalence of arsenic-induced skin lesions, it is important to assess the impact of this problem among the target population, and to make future planning. We evaluated the association between multi-levels inorganic arsenic exposure from drinking water and skin lesions in an arsenic-affected area in Inner Mongolia, China. One hundred nine and 32 subjects in high (>50 microg/liter) and low (<50 microg/liter) arsenic-affected villages were recruited and had the detailed physical examination with special emphasis on arsenic-related skin lesions. Arsenic exposure was measured for each participant with respect to iAs concentration of primary well and the duration using the well. Arsenic-induced skin lesions including keratosis, pigmentation, and/or depigmentation were diagnosed in 56 and 3 subjects in the two villages, respectively. Logistic regression was conducted to calculate odd ratios of skin lesions associated with arsenic exposure with adjustments for sex, age group, smoking and duration of exposure. A consistent dose-response relationship between arsenic exposure level and skin lesion risk was observed. Compared to those with iAs concentration <50 microg/liter, the adjusted odds ratios of skin lesions for the subjects with 51-99, 100-149 and >150 microg/liter were 33.3% (OR =15.50, 95% CI: 1.53-248.70), 46.7% (OR =16.10, 95% CI: 3.73-69.63) and 55.7% (OR= 25.70, 95% CI: 6.43-102.87), respectively. Duration of using well was not associated with increased risk of skin lesions in this population; (OR =1.68, 95% CI: 0.40-6.91 for 6-15 years, OR = 2.30, 95% CI: 0.58-9.14 for over 15 years) compared with the duration of less than 5 years.

  19. Effect of occupational EMF exposure from radar at two different frequency bands on plasma melatonin and serotonin levels.

    PubMed

    Singh, Sarika; Mani, Kumar Vyonkesh; Kapoor, Neeru

    2015-05-01

    To delineate the effect of chronic electromagnetic field (EMF) exposure from radar on plasma melatonin and serotonin levels in occupationally exposed military personnel. A total of 166 male military personnel participated in the study out of which only 155 joined for blood draw. They were divided into three sets: Control group (n = 68), exposure group I (n = 40) exposed to 8-12 GHz and exposure group II (n = 58) working with radar at 12.5-18 GHz frequency. The three groups were further split into two groups according to their years of service (up to 10 years and > 10 years) in order to investigate the effect of years of exposure from radar. Melatonin and serotonin levels were estimated by enzyme immunoassay in fasting blood samples collected from 06:00-07:00 h. EMF measurements were recorded at different locations using Satimo EME Guard 'Personal Exposure Meter' and Narda 'Broad Band Field Meter'. The group I exposed population registered a minor though not significant decrease in plasma melatonin concentration while the other group II exposed population registered statistically significant decline in melatonin concentration when compared with controls. Highly significant increase in plasma serotonin levels was found in exposure group II when compared to control whereas marginal non-significant rise was also registered in exposure group I in comparison to control. Exposure in terms of length of service up to 10 years did not produce any significant effect in the indoleamine levels in both the exposure groups when they were compared with their respective control groups. Whereas, length of service greater than 10 years was observed to decrease and increase respectively the melatonin and serotonin concentration significantly in exposure group II but not in exposure group I. However, correlation test did not yield any significant association between years of service and melatonin or serotonin levels respectively in both the exposure sets I and II. No significant

  20. Assessment of secondhand smoke exposure at school among U.S. Middle and high school students.

    PubMed

    Olufajo, Olubode Ademola; Agaku, Israel Terungwa

    2015-06-01

    To obtain nationally representative estimates of the prevalence of secondhand smoke (SHS) exposure at U.S. schools, we assessed the prevalence and correlates of SHS exposure at school among U.S. middle and high school students using data from the 2011 National Youth Tobacco Survey comprising of 18,866 students spread across all the U.S. states. Overall prevalence of SHS exposure at school was 25.7% (95% CI: [23.6%, 27.8%]). Multivariate logistic regression indicated that having ≥1 smoker friends (adjusted Odds Ratio [aOR] = 2.92; p < .001); being a smoker (aOR = 2.75; p < .001); and being aged 13-16 years, or ≥17 years (vs. 9-12 years) significantly increased the likelihood of SHS exposure. Understanding the health risks of SHS exposure alone did not seem to play a significant role in reducing exposure (aOR = .89; p = .342). These findings show there are significant levels of SHS exposure among students at U.S. middle and high schools, and sustained multipronged efforts are needed to reduce youth SHS exposure.

  1. Low G preconditioning reduces liver injury induced by high +Gz exposure in rats

    PubMed Central

    Shi, Bin; Feng, Zhi-Qiang; Li, Wen-Bing; Zhang, Hong-Yi

    2015-01-01

    AIM: To investigate the effect of repeated lower +Gz exposure on liver injury induced by high +Gz exposure in rats. METHODS: Sixty male Wister rats were randomly divided into a blank control group, a low G preconditioning group (LG) (exposed to +4 Gz/5 min per day for 3 d before +10 Gz/5 min exposure), and a +10 Gz/5 min group (10G) (n = 20 in each group). Blood specimens and liver tissue were harvested at 0 h and 6 h after +10 Gz/5 min exposure. Liver function was analyzed by measuring serum alanine transaminase (ALT) and aspartate aminotransferase (AST) levels, and liver injury was further assessed by histopathological observation. Malondialdehyde (MDA), superoxide dismutase (SOD) and Na+-K+-ATPase were determined in hepatic tissue. RESULTS: The group LG had lower ALT, AST, and MDA values at 0 h after exposure than those in group 10G. SOD values and Na+-K+-ATPase activity in the LG group were higher than in group 10G 0 h post-exposure. Hepatocyte injury was significantly less in group LG than in group 10G on histopathological evaluation. CONCLUSION: It is suggested that repeated low +Gz exposure shows a protective effect on liver injury induced by high +Gz exposure in rats. PMID:26074692

  2. Effective exposure level and diagnostic performance in endodontic radiography

    SciTech Connect

    Okano, T.; Wiebe, J.D.; Webber, R.L.; Wagner, R.F.

    1983-05-01

    Image quality is limited by the information capacity of the image-forming system and can be computed from three parameters: contrast, resolution, and noise. These parameters can be combined to yield a single measure which determines the maximum amount of information obtainable from any x-ray system and is called the noise-equivalent number of quanta (NEQ) per unit area. The effects of image quality, expressed as noise-equivalent number of quanta (NEQ) per unit area, on the radiographic performance by dentists reading the position of an endodontic file in a root canal were studied. Three different speed films were used in conjunction with a fixed screen. Components of variance associated with the position of the tooth apex and the tip of an endodontic file in a root canal were compared for the effect of different NEQs and observers. Results show that the standard deviation in locating a file tip and tooth apex may be a linear function of log NEQ. These findings indicate that a significant reduction in exposure would have a relatively small effect on the precision of endodontic distance measurements.

  3. High-resolution metabolomics of occupational exposure to trichloroethylene

    PubMed Central

    Walker, Douglas I; Uppal, Karan; Zhang, Luoping; Vermeulen, Roel; Smith, Martyn; Hu, Wei; Purdue, Mark P; Tang, Xiaojiang; Reiss, Boris; Kim, Sungkyoon; Li, Laiyu; Huang, Hanlin; Pennell, Kurt D; Jones, Dean P; Rothman, Nathaniel; Lan, Qing

    2016-01-01

    Background: Occupational exposure to trichloroethylene (TCE) has been linked to adverse health outcomes including non-Hodgkin’s lymphoma and kidney and liver cancer; however, TCE’s mode of action for development of these diseases in humans is not well understood. Methods: Non-targeted metabolomics analysis of plasma obtained from 80 TCE-exposed workers [full shift exposure range of 0.4 to 230 parts-per-million of air (ppma)] and 95 matched controls were completed by ultra-high resolution mass spectrometry. Biological response to TCE exposure was determined using a metabolome-wide association study (MWAS) framework, with metabolic changes and plasma TCE metabolites evaluated by dose-response and pathway enrichment. Biological perturbations were then linked to immunological, renal and exposure molecular markers measured in the same population. Results: Metabolic features associated with TCE exposure included known TCE metabolites, unidentifiable chlorinated compounds and endogenous metabolites. Exposure resulted in a systemic response in endogenous metabolism, including disruption in purine catabolism and decreases in sulphur amino acid and bile acid biosynthesis pathways. Metabolite associations with TCE exposure included uric acid (β = 0.13, P-value = 3.6 × 10−5), glutamine (β = 0.08, P-value = 0.0013), cystine (β = 0.75, P-value = 0.0022), methylthioadenosine (β = −1.6, P-value = 0.0043), taurine (β = −2.4, P-value = 0.0011) and chenodeoxycholic acid (β = −1.3, P-value = 0.0039), which are consistent with known toxic effects of TCE, including immunosuppression, hepatotoxicity and nephrotoxicity. Correlation with additional exposure markers and physiological endpoints supported known disease associations. Conclusions: High-resolution metabolomics correlates measured occupational exposure to internal dose and metabolic response, providing insight into molecular mechanisms of exposure

  4. High levels of concomitant behavioral health disorders among patients presenting for HIV non-occupational post-exposure prophylaxis at a Boston community health center between 1997 and 2013

    PubMed Central

    Jain, Sachin; Oldenburg, Catherine E.; Mimiaga, Matthew J.; Mayer, Kenneth H.

    2015-01-01

    A paucity of information regarding mental health exists for patients presenting for HIV non occupational post-exposure prophylaxis (nPEP). We reviewed electronic medical records of 894 adult nPEP patients seen at a large Boston community health center between 1997 and 2013. Of 821 patients with consensual sexual exposures, 88.3% were men who have sex with men, and 40.0% had a mental health diagnosis. Diagnoses included: depression (24.4%), anxiety (21.9%), attention deficit disorder (7.8%), post-traumatic stress disorder (3.3%), and psychotic disorders (3.3%). Of 129 patients with substance use disorders, alcohol dependence (65.9%) and crystal methamphetamine (43.4%) predominated. Unprotected receptive anal intercourse was associated with psychotic disorders (aOR=4.86;95%CI:1.76–13.5) and substance use disorders (aOR=1.89;95%CI:1.28–2.80). Substance use at the time of exposure was associated with: depression (aOR=1.95;95%CI:1.36–2.80), anxiety (aOR=2.22;95%CI:1.51–3.25), attention deficit disorder (aOR=1.96;95%CI:1.18–3.27), and substance use disorder (aOR=4.78;95%CI:3.30–6.93). Mental illness should be screened for and addressed at nPEP visits to optimize HIV risk-reduction. PMID:25689892

  5. [Assessment of occupational exposure to aromatic polycyclic hydrocarbons determining urinary levels of 1-pyrenol].

    PubMed

    Pavanello, S; Genova, A; Foà, V; Clonfero, E

    2000-01-01

    In conformity with Italian law 626/94, occupational exposure to Polycyclic Aromatic Hydrocarbons (PAH) in several types of work environments was assessed by analysing urinary levels of 1-pyrenol. A total of 231 non-smokers exposed to PAH (82 workers, employed in two different thermoelectric power plants using combustible oil (30 subjects from plant A and 52 from plant B), 18 subjects working for a company recovering exhausted oils, 12 working on rubber production, 10 on road surface asphalting operations, 22 working in the anodizing section of an aluminium plant, 27 chimney-sweeps, and 60 coke-oven workers (30 topside workers, and 30 doing other jobs)) were enrolled. There were also 53 non-smoker control subjects, not occupationally exposed to PAH. Current smokers were excluded, since smoking is an important confounding factor when occupational exposure to low PAH concentrations are monitored. Confounding factors, i.e., diet and passive smoking, were checked by means of a questionnaire which, in addition to personal data and habits, also requested specific details about the type of diet followed and possible exposure to passive smoking during the 24-hour period preceding urine collection. In controls, exposure to PAH in the diet significantly increased 1-pyrenol levels in urine: in subjects introducing > or = 1 microgram of pyrene with the diet, the mean urinary level of 1-pyrenol was significantly higher than that introduced with < 1 microgram (high versus low dietary intake, mean +/- SD, 0.08 +/- 0.13 and 0.04 +/- 0.06 1-pyrenol mumoles/mole of creatinine, respectively; Mann-Whitney U-test Z = 2.67, p < 0.01). Conversely, passive smoking did not influence 1-pyrenol levels. In the overall population (controls and exposed), multiple linear regression analysis showed that levels of urinary 1-pyrenol were significantly influenced by occupational exposure to PAH in asphalt workers, anodizing plant workers, chimney-sweeps, and coke-oven workers, both those working at

  6. Endotoxin exposure assessment in wood-processing industry: airborne versus settled dust levels.

    PubMed

    Pipinić, Ivana Sabolić; Varnai, Veda Marija; Lucić, Ruzica Beljo; Cavlović, Ankica; Prester, Ljerka; Orct, Tatjana; Macan, Jelena

    2010-06-01

    Wood processing is usually performed in environments with large amounts of endotoxin-rich bioaerosols that are associated with a variety of health effects. The aim of this preliminary study was to assess the relation between endotoxin levels in settled and airborne dust in wood-processing industry. Ten pairs of airborne and settled dust samples were collected in a sawmill and parquet manufacture of two wood-processing plants in Croatia. Endotoxin was assayed with a chromogenic end-point LAL (Limulus amebocyte lysate) method. The results showed that endotoxin levels in airborne respirable dust were above the proposed occupational exposure limit of 125 EU m(-3) and could be considered hazardous for the respiratory system. In settled dust they ranged between 229.7 EU mg(-1) and 604.3 EU mg(-1) and in airborne dust between 166.8 EU mg(-1) and 671.6 EU m(-3), but there was no significant correlation between them (Spearman's rho=0.358, P=0.310). This study points to sawmill settled dust as endotoxin reservoir and suggests that it may add to already high exposure to airborne endotoxins associated with wood processing. Investigations of the relation between settled and airborne endotoxin levels should be continued to better understand the sources and sites of endotoxin contamination in wood-processing industry.

  7. Effects of Oral Exposure to Fungicides on Honey Bee Nutrition and Virus Levels.

    PubMed

    Degrandi-Hoffman, Gloria; Chen, Yanping; Watkins Dejong, Emily; Chambers, Mona L; Hidalgo, Geoffrey

    2015-12-01

    Sublethal exposure to fungicides can affect honey bees (Apis mellifera L.) in ways that resemble malnutrition. These include reduced brood rearing, queen loss, and increased pathogen levels. We examined the effects of oral exposure to the fungicides boscalid and pyraclostrobin on factors affecting colony nutrition and immune function including pollen consumption, protein digestion, hemolymph protein titers, and changes in virus levels. Because the fungicides are respiratory inhibitors, we also measured ATP concentrations in flight muscle. The effects were evaluated in 3- and 7-d-old worker bees at high fungicide concentrations in cage studies, and at field-relevant concentrations in colony studies. Though fungicide levels differed greatly between the cage and colony studies, similar effects were observed. Hemolymph protein concentrations were comparable between bees feeding on pollen with and without added fungicides. However, in both cage and colony studies, bees consumed less pollen containing fungicides and digested less of the protein. Bees fed fungicide-treated pollen also had lower ATP concentrations and higher virus titers. The combination of effects we detected could produce symptoms that are similar to those from poor nutrition and weaken colonies making them more vulnerable to loss from additional stressors such as parasites and pathogens. Published by Oxford University Press on behalf of Entomological Society of America 2015. This work is written by US Government employees and is in the public domain in the US.

  8. Associations between cadmium exposure and circulating levels of sex hormones in postmenopausal women

    SciTech Connect

    Ali, Imran; Engström, Annette; Vahter, Marie; Skerfving, Staffan; Lundh, Thomas; Lidfeldt, Jonas; Samsioe, Göran; Halldin, Krister; Åkesson, Agneta

    2014-10-15

    Recent epidemiological as well as in vivo and in vitro studies collectively suggest that the metalloestrogen cadmium (Cd) could be a potential risk factor for hormone-related cancers in particularly breast cancer. Assessment of the association between Cd exposure and levels of endogenous sex hormones is of pivotal importance, as increased levels of such have been associated with a higher risk of breast cancer in postmenopausal women. The present study investigated the perceived relationship (multivariable-adjusted linear regression analyses) between Cd exposure [blood Cd (B-Cd) and urinary Cd (U-Cd)], and serum levels of androstenedione, testosterone, estradiol, and sex-hormone binding globulin (SHBG), in 438 postmenopausal Swedish women without hormone replacement therapy (HRT). A significant positive association between B-Cd (median 3.4 nmol/L) and serum testosterone levels, as well as a significant inverse association between B-Cd and serum estradiol levels and with the estradiol/testosterone ratio were encountered. However, U-Cd (median 0.69 nmol/mmol creatinine) was inversely associated with serum estradiol levels only. Our data may suggest that Cd interferes with the levels of testosterone and estradiol in postmenopausal women, which might have implications for breast cancer risk. - Highlights: • Low level cadmium exposure may interfere with the levels of steroid hormones. • Cadmium exposure was associated with increased serum testosterone concentrations. • Cadmium exposure was associated with decreased estradiol/testosterone ratio. • Cadmium exposure may have implications for breast-cancer promotion.

  9. DEFENSE HIGH LEVEL WASTE GLASS DEGRADATION

    SciTech Connect

    W. Ebert

    2001-09-20

    The purpose of this Analysis/Model Report (AMR) is to document the analyses that were done to develop models for radionuclide release from high-level waste (HLW) glass dissolution that can be integrated into performance assessment (PA) calculations conducted to support site recommendation and license application for the Yucca Mountain site. This report was developed in accordance with the ''Technical Work Plan for Waste Form Degradation Process Model Report for SR'' (CRWMS M&O 2000a). It specifically addresses the item, ''Defense High Level Waste Glass Degradation'', of the product technical work plan. The AP-3.15Q Attachment 1 screening criteria determines the importance for its intended use of the HLW glass model derived herein to be in the category ''Other Factors for the Postclosure Safety Case-Waste Form Performance'', and thus indicates that this factor does not contribute significantly to the postclosure safety strategy. Because the release of radionuclides from the glass will depend on the prior dissolution of the glass, the dissolution rate of the glass imposes an upper bound on the radionuclide release rate. The approach taken to provide a bound for the radionuclide release is to develop models that can be used to calculate the dissolution rate of waste glass when contacted by water in the disposal site. The release rate of a particular radionuclide can then be calculated by multiplying the glass dissolution rate by the mass fraction of that radionuclide in the glass and by the surface area of glass contacted by water. The scope includes consideration of the three modes by which water may contact waste glass in the disposal system: contact by humid air, dripping water, and immersion. The models for glass dissolution under these contact modes are all based on the rate expression for aqueous dissolution of borosilicate glasses. The mechanism and rate expression for aqueous dissolution are adequately understood; the analyses in this AMR were conducted to

  10. Low level exposure to weathered crude oil causes genetic damage and malformations in larval herring

    SciTech Connect

    Carls, M.; Rice, S.D.; Hose, J.E.

    1995-12-31

    An initial concentration of 0.7 ppb polycyclic aromatic hydrocarbons (PAHs) in weathered Alaska North Slope crude oil caused genetic damage in newly hatched Pacific herring (Clupea pallasi) exposed for 16 days during incubation. The endpoint for genetic damage was a significant increase in the percentage of anaphase aberrations in pectoral fin cells, a response that has been previously shown to be a highly sensitive indicator of crude oil exposure in larval herring. At this exposure level, there were also significant decreases in the percentages of larval survival, normal development and competent swimming, and increased percentages of yolk sac edema. Composition of the PAH, which ranged from naphthalenes through chrysenes, was weighted toward the larger ring compounds, particularly phenanthrenes. Genetic response was not as sensitive an indicator of oil exposure as yolk sac edema, jaw size, and formation of pectoral fin rays. The consequences of chromosomal aberrations in larval herring are not clear. Other experiments have shown that although the frequency of genetic damage decreases with age, malformations persist and are coupled with growth reductions. It is likely that malformed larvae die; evidence for this comes from simultaneous measurements of mortality, malformations and genetic damage in the field.

  11. Human brain mercury levels related to exposure to amalgam fillings.

    PubMed

    Ertaş, E; Aksoy, A; Turla, A; Karaarslan, E S; Karaarslan, B; Aydın, A; Eken, A

    2014-08-01

    The safety of dental amalgam as the primary material in dental restoration treatments has been debated since its introduction. It is widely accepted that amalgam restorations continuously release elemental mercury (Hg) vapor, which is inhaled and absorbed by the body and distributed to tissues, including the brain. The aim of the present study was to investigate whether the presence of amalgam fillings is correlated with brain Hg level. The Hg levels in the parietal lobes of the brains of 32 cadavers were analyzed with an atomic absorption spectrometer with the mercury hydride system. A total of 32 brain samples were tested; of these, 10 were from cadavers with amalgam fillings, while 22 of them were amalgam free. Hg was detected in 60.0% (6 of 10) of the samples in the amalgam group and in 36.3% (8 of 22) in the amalgam-free group. The average Hg level of the amalgam group was 0.97 ± 0.83 µg/g (minimum: 0.3 µg/g and maximum: 2.34 µg/g), and in the amalgam-free group, it was 1.06 ± 0.57 µg/g (minimum: 0.17 µg/g and maximum: 1.76 µg/g). The results of the present study showed no correlation between the presence of amalgam fillings and brain Hg level.

  12. High-Level Binocular Rivalry Effects

    PubMed Central

    Wolf, Michal; Hochstein, Shaul

    2011-01-01

    Binocular rivalry (BR) occurs when the brain cannot fuse percepts from the two eyes because they are different. We review results relating to an ongoing controversy regarding the cortical site of the BR mechanism. Some BR qualities suggest it is low-level: (1) BR, as its name implies, is usually between eyes and only low-levels have access to utrocular information. (2) All input to one eye is suppressed: blurring doesn’t stimulate accommodation; pupilary constrictions are reduced; probe detection is reduced. (3) Rivalry is affected by low-level attributes, contrast, spatial frequency, brightness, motion. (4) There is limited priming due to suppressed words or pictures. On the other hand, recent studies favor a high-level mechanism: (1) Rivalry occurs between patterns, not eyes, as in patchwork rivalry or a swapping paradigm. (2) Attention affects alternations. (3) Context affects dominance. There is conflicting evidence from physiological studies (single cell and fMRI) regarding cortical level(s) of conscious perception. We discuss the possibility of multiple BR sites and theoretical considerations that rule out this solution. We present new data regarding the locus of the BR switch by manipulating stimulus semantic content or high-level characteristics. Since these variations are represented at higher cortical levels, their affecting rivalry supports high-level BR intervention. In Experiment I, we measure rivalry when one eye views words and the other non-words and find significantly longer dominance durations for non-words. In Experiment II, we find longer dominance times for line drawings of simple, structurally impossible figures than for similar, possible objects. In Experiment III, we test the influence of idiomatic context on rivalry between words. Results show that generally words within their idiomatic context have longer mean dominance durations. We conclude that BR has high-level cortical influences, and may be controlled by a high-level mechanism

  13. High-level binocular rivalry effects.

    PubMed

    Wolf, Michal; Hochstein, Shaul

    2011-01-01

    Binocular rivalry (BR) occurs when the brain cannot fuse percepts from the two eyes because they are different. We review results relating to an ongoing controversy regarding the cortical site of the BR mechanism. Some BR qualities suggest it is low-level: (1) BR, as its name implies, is usually between eyes and only low-levels have access to utrocular information. (2) All input to one eye is suppressed: blurring doesn't stimulate accommodation; pupilary constrictions are reduced; probe detection is reduced. (3) Rivalry is affected by low-level attributes, contrast, spatial frequency, brightness, motion. (4) There is limited priming due to suppressed words or pictures. On the other hand, recent studies favor a high-level mechanism: (1) Rivalry occurs between patterns, not eyes, as in patchwork rivalry or a swapping paradigm. (2) Attention affects alternations. (3) Context affects dominance. There is conflicting evidence from physiological studies (single cell and fMRI) regarding cortical level(s) of conscious perception. We discuss the possibility of multiple BR sites and theoretical considerations that rule out this solution. We present new data regarding the locus of the BR switch by manipulating stimulus semantic content or high-level characteristics. Since these variations are represented at higher cortical levels, their affecting rivalry supports high-level BR intervention. In Experiment I, we measure rivalry when one eye views words and the other non-words and find significantly longer dominance durations for non-words. In Experiment II, we find longer dominance times for line drawings of simple, structurally impossible figures than for similar, possible objects. In Experiment III, we test the influence of idiomatic context on rivalry between words. Results show that generally words within their idiomatic context have longer mean dominance durations. We conclude that BR has high-level cortical influences, and may be controlled by a high-level mechanism.

  14. Accommodating brightness and exposure levels in densitometry of stained polyacrylamide electrophoresis gels

    SciTech Connect

    Tan, Han Yen; Ng, Tuck Wah; Liew, Oi Wah

    2010-03-20

    Flatbed scanner densitometers can be operated under various illumination and recording exposure levels. In this work, we show that optical density measurement accuracy, sensitivity, and stability of stained polyacrylamide electrophoresis gel densitometry are crucially dependent on these two factors (brightness and exposure level), notwithstanding that the source is monochromatic, spatially uniform, and the measurements are made using an accurately calibrated step wedge in tandem. We further outline a method to accommodate the intensity deviations over a range of illumination and exposure levels in order to maintain sensitivity and repeatability in the computed optical densities. Comparisons were also made with results from a commercial densitometer.

  15. New High Throughput Methods to Estimate Chemical Exposure

    EPA Science Inventory

    EPA has made many recent advances in high throughput bioactivity testing. However, concurrent advances in rapid, quantitative prediction of human and ecological exposures have been lacking, despite the clear importance of both measures for a risk-based approach to prioritizing an...

  16. New High Throughput Methods to Estimate Chemical Exposure

    EPA Science Inventory

    EPA has made many recent advances in high throughput bioactivity testing. However, concurrent advances in rapid, quantitative prediction of human and ecological exposures have been lacking, despite the clear importance of both measures for a risk-based approach to prioritizing an...

  17. Effects of Hypergravity Exposure on Prolactin Levels in Pre-parturient , Parturient and Lactating Rat Dams

    NASA Technical Reports Server (NTRS)

    Baer. Lisa A.; Wade, Charles E.; Ronca, April E.; Sun, Sid (Technical Monitor)

    2001-01-01

    We analyzed the effects of 2.0-g, 1.75-g and 1.5-g hypergravity exposure on plasma concentrations of the lactotrophic hormone, prolactin (PRL), in female rats on pre-parturient (Gestation Day 20), parturient (Post-natal day 0) and lactating (P10) days. PRL levels have been found to be reduced in rat dams around the time of birth following exposure to gravitational loads varying from 2.16 to 3.14-g (Megory et. al., Aviation, Space and Environs 1129-1135, 1984). It has also been reported that at these high gravitational loads, neonatal mortality has been extremely high, suggesting a possible interaction between dam PRL concentration and neonatal outcome. We have previously reported no significant differences in PRL levels of parturient (PO) and lactating (P6 & P 15) dams when exposed to 1.5-g hypergravity, but did observe a slight elevation of PRL on PO and P 15, with a decrease on P6. In the present study, time-bred pregnant dams were exposed to either continuous 2.0-g, 1.75-g or 1.5-g centrifugation, beginning on Gestational day (G) 11 of the rats' 22-day pregnancy. We observed no significant differences in PRL concentrations between SC and any of the HG conditions. On G20 and PO, PRL concentrations of the 2.0-g and 1.5-g groups were slightly elevated as compared to SC. Similar to what we previously reported. PRL secretion was elevated in both HG and SC conditions on the day of birth relative to later during lactation, but on P10 it appeared to be reduced in HG relative to SC dams. These findings suggests that hypergravity slightly elevates plasma concentration of PRL in pre-parturient and lactating rat dams, with effects most pronounced during the periparturitional period and in a direction opposite to that observed following microgravity exposure.

  18. Effects of Hypergravity Exposure on Prolactin Levels in Pre-parturient , Parturient and Lactating Rat Dams

    NASA Technical Reports Server (NTRS)

    Baer. Lisa A.; Wade, Charles E.; Ronca, April E.; Sun, Sid (Technical Monitor)

    2001-01-01

    We analyzed the effects of 2.0-g, 1.75-g and 1.5-g hypergravity exposure on plasma concentrations of the lactotrophic hormone, prolactin (PRL), in female rats on pre-parturient (Gestation Day 20), parturient (Post-natal day 0) and lactating (P10) days. PRL levels have been found to be reduced in rat dams around the time of birth following exposure to gravitational loads varying from 2.16 to 3.14-g (Megory et. al., Aviation, Space and Environs 1129-1135, 1984). It has also been reported that at these high gravitational loads, neonatal mortality has been extremely high, suggesting a possible interaction between dam PRL concentration and neonatal outcome. We have previously reported no significant differences in PRL levels of parturient (PO) and lactating (P6 & P 15) dams when exposed to 1.5-g hypergravity, but did observe a slight elevation of PRL on PO and P 15, with a decrease on P6. In the present study, time-bred pregnant dams were exposed to either continuous 2.0-g, 1.75-g or 1.5-g centrifugation, beginning on Gestational day (G) 11 of the rats' 22-day pregnancy. We observed no significant differences in PRL concentrations between SC and any of the HG conditions. On G20 and PO, PRL concentrations of the 2.0-g and 1.5-g groups were slightly elevated as compared to SC. Similar to what we previously reported. PRL secretion was elevated in both HG and SC conditions on the day of birth relative to later during lactation, but on P10 it appeared to be reduced in HG relative to SC dams. These findings suggests that hypergravity slightly elevates plasma concentration of PRL in pre-parturient and lactating rat dams, with effects most pronounced during the periparturitional period and in a direction opposite to that observed following microgravity exposure.

  19. Acute low-level microwave exposure and central cholinergic activity: studies on irradiation parameters

    SciTech Connect

    Lai, H.; Horita, A.; Guy, A.W.

    1988-01-01

    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 the exposure conditions studied. We conclude that depending on the parameters of the radiation, microwaves can elicit specific and generalized biological effects.

  20. 28 CFR 79.44 - Proof of working level month exposure to radiation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... radiation. 79.44 Section 79.44 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) CLAIMS UNDER THE RADIATION EXPOSURE COMPENSATION ACT Eligibility Criteria for Claims by Uranium Miners § 79.44 Proof of working level month exposure to radiation. (a) If one or more of the sources in § 79.43(a) contain a...

  1. 28 CFR 79.44 - Proof of working level month exposure to radiation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... radiation. 79.44 Section 79.44 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) CLAIMS UNDER THE RADIATION EXPOSURE COMPENSATION ACT Eligibility Criteria for Claims by Uranium Miners § 79.44 Proof of working level month exposure to radiation. (a) If one or more of the sources in § 79.43(a) contain a...

  2. 28 CFR 79.44 - Proof of working level month exposure to radiation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... radiation. 79.44 Section 79.44 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) CLAIMS UNDER THE RADIATION EXPOSURE COMPENSATION ACT Eligibility Criteria for Claims by Uranium Miners § 79.44 Proof of working level month exposure to radiation. (a) If one or more of the sources in § 79.43(a) contain a...

  3. 28 CFR 79.44 - Proof of working level month exposure to radiation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... radiation. 79.44 Section 79.44 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) CLAIMS UNDER THE RADIATION EXPOSURE COMPENSATION ACT Eligibility Criteria for Claims by Uranium Miners § 79.44 Proof of working level month exposure to radiation. (a) If one or more of the sources in § 79.43(a) contain a...

  4. 28 CFR 79.44 - Proof of working level month exposure to radiation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... radiation. 79.44 Section 79.44 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) CLAIMS UNDER THE RADIATION EXPOSURE COMPENSATION ACT Eligibility Criteria for Claims by Uranium Miners § 79.44 Proof of working level month exposure to radiation. (a) If one or more of the sources in § 79.43(a) contain a...

  5. Radiation exposure at ground level by secondary cosmic radiation.

    PubMed

    Wissmann, F; Dangendorf, V; Schrewe, U

    2005-01-01

    The contribution of the charged component of secondary cosmic radiation to the ambient dose equivalent H*(10) at ground level is investigated using the muon detector MUDOS and a TEPC detector surrounded by the coincidence detector CACS to identify charged particles. The ambient dose equivalent rate H*(10)T as measured with the TEPC/CACS is used to calibrate the MUDOS count rate in terms of H*(10). First results from long-term measurements at the PTB reference site for ambient radiation dosimetry are reported. The air pressure corrected dose rate shows, as expected, a strong correlation with the neutron count rate as measured with the Kiel neutron monitor. The measured seasonal variations exhibit a negative correlation with the temperature changes in the upper layers of the atmosphere where the ground level muons are produced.

  6. Quantification of personal exposure concentrations to gasoline vehicle emissions in high-end exposure microenvironments: effects of fuel and season.

    PubMed

    Zielinska, B; Fujita, E; Ollison, W; Campbell, D; Sagebiel, J

    2012-11-01

    Mobile-source air toxic (MSAT) levels increase in confining microenvironments (MEs) with numerous emission sources of vehicle exhaust or evaporative emissions or during high-load and cold-start conditions. Reformulated fuels are expected to reduce MSAT and ozone precursor emissions. This study, required under the Clean Air Act Section 211b, evaluated high-end exposures in cities using reformulated (methyl tertiary-butyl ether [MTBE] or ethanol [EtOH]) fuels and conventional gasoline blends. The study investigates 13 high-end MEs, sampling under enhanced exposure conditions expected to result in maximal fuel and exhaust component exposures to carbon monoxide (CO), carbon dioxide (CO2), BTEX (benzene, toluene, ethylbenzene, xylenes), MTBE, 1,3-butadiene (1,3-BD), EtOH,formaldehyde (HCHO), and acetaldehyde (CH3CHO). The authors found that day-to-day ME variations in high-end benzene, 1,3-BD, HCHO, and CO concentrations are substantial, but independent of gasoline composition and season, and related to the activity and emission rates of ME sources, which differ from day to day.

  7. Interventions for Individuals With High Levels of Needle Fear

    PubMed Central

    Noel, Melanie; Taddio, Anna; Antony, Martin M.; Asmundson, Gordon J.G.; Riddell, Rebecca Pillai; Chambers, Christine T.; Shah, Vibhuti

    2015-01-01

    Background: This systematic review evaluated the effectiveness of exposure-based psychological and physical interventions for the management of high levels of needle fear and/or phobia and fainting in children and adults. Design/Methods: A systematic review identified relevant randomized and quasi-randomized controlled trials of children, adults, or both with high levels of needle fear, including phobia (if not available, then populations with other specific phobias were included). Critically important outcomes were self-reported fear specific to the feared situation and stimulus (psychological interventions) or fainting (applied muscle tension). Data were pooled using standardized mean difference (SMD) or relative risk with 95% confidence intervals. Results: The systematic review included 11 trials. In vivo exposure-based therapy for children 7 years and above showed benefit on specific fear (n=234; SMD: −1.71 [95% CI: −2.72, −0.7]). In vivo exposure-based therapy with adults reduced fear of needles posttreatment (n=20; SMD: −1.09 [−2.04, −0.14]) but not at 1-year follow-up (n=20; SMD: −0.28 [−1.16, 0.6]). Compared with single session, a benefit was observed for multiple sessions of exposure-based therapy posttreatment (n=93; SMD: −0.66 [−1.08, −0.24]) but not after 1 year (n=83; SMD: −0.37 [−0.87, 0.13]). Non in vivo e.g., imaginal exposure-based therapy in children reduced specific fear posttreatment (n=41; SMD: −0.88 [−1.7, −0.05]) and at 3 months (n=24; SMD: −0.89 [−1.73, −0.04]). Non in vivo exposure-based therapy for adults showed benefit on specific fear (n=68; SMD: −0.62 [−1.11, −0.14]) but not procedural fear (n=17; SMD: 0.18 [−0.87, 1.23]). Applied tension showed benefit on fainting posttreatment (n=20; SMD: −1.16 [−2.12, −0.19]) and after 1 year (n=20; SMD: −0.97 [−1.91, −0.03]) compared with exposure alone. Conclusions: Exposure-based psychological interventions and applied muscle tension show

  8. Gain, Level, And Exposure Control For A Television Camera

    NASA Technical Reports Server (NTRS)

    Major, Geoffrey J.; Hetherington, Rolfe W.

    1992-01-01

    Automatic-level-control/automatic-gain-control (ALC/AGC) system for charge-coupled-device (CCD) color television camera prevents over-loading in bright scenes using technique for measuring brightness of scene from red, green, and blue output signals and processing these into adjustments of video amplifiers and iris on camera lens. System faster, does not distort video brightness signals, and built with smaller components.

  9. Gain, Level, And Exposure Control For A Television Camera

    NASA Technical Reports Server (NTRS)

    Major, Geoffrey J.; Hetherington, Rolfe W.

    1992-01-01

    Automatic-level-control/automatic-gain-control (ALC/AGC) system for charge-coupled-device (CCD) color television camera prevents over-loading in bright scenes using technique for measuring brightness of scene from red, green, and blue output signals and processing these into adjustments of video amplifiers and iris on camera lens. System faster, does not distort video brightness signals, and built with smaller components.

  10. Ozone Exposure System Designed and Used to High-Altitude Airship Materials

    NASA Technical Reports Server (NTRS)

    Miller, Sharon K.

    2005-01-01

    High-altitude airships can receive high doses of ozone over short mission durations. For example, in 1 year at an altitude of 70,000 ft, the ozone fluence (number arriving per unit area) can be as high as 1.2 1024 molecules/sq cm. Ozone exposure at these levels can embrittle materials or change the performance of solar cells. It is important to expose components and materials to the expected ozone dosage to determine if the ozone exposure could cause any mission-critical failures.

  11. Exhaled nitric oxide decreases upon acute exposure to high-altitude hypoxia.

    PubMed

    Brown, Daniel E; Beall, Cynthia M; Strohl, Kingman P; Mills, Phoebe S

    2006-01-01

    Nitric oxide (NO) is a vasodilator that plays a role in blood flow and oxygen delivery. Acute hypoxia down regulates NO synthesis, a response that may exacerbate hypoxic stress by decreasing blood flow. This study was designed to test the hypotheses that pulmonary NO decreases upon acute exposure to high-altitude hypoxia and that relatively low levels of NO at altitude are associated with greater stress as reflected in more symptoms of acute mountain sickness (AMS). A sample of 47 healthy, adult, nonsmoking, sea-level residents provided measurements at sea level, at 2,800 m, and at 0-, 2-, and 3-h exposure times at 4,200 m altitude on Mauna Kea, Hawaii. Measurements were made of exhaled NO, oxygen saturation of hemoglobin, heart rate, and reported symptoms of AMS. The partial pressure of NO concentration in exhaled breath decreased significantly from a sea level mean of 4.2 nmHg to 3.8 nmHg at 2,800 m and 3.4 nmHg at 4,200 m. NO concentration in exhaled breath did not change significantly over a 3-h exposure at 4,200 m and recovered to pre-exposure baseline upon return to sea level. There was no significant association between the level of NO exhaled and the number of self-reported symptoms of AMS during this brief exposure. Am. J. Hum. Biol. 18:196-202, 2006. (c) 2006 Wiley-Liss, Inc.

  12. Exposure level and distribution characteristics of airborne bacteria and fungi in Seoul metropolitan subway stations.

    PubMed

    Kim, Ki Youn; Kim, Yoon Shin; Kim, Daekeun; Kim, Hyeon Tae

    2011-01-01

    The exposure level and distribution characteristics of airborne bacteria and fungi were assessed in the workers' activity areas (station office, bedroom, ticket office and driver's seat) and passengers' activity areas (station precinct, inside the passenger carriage, and platform) of the Seoul metropolitan subway. Among investigated areas, the levels of airborne bacteria and fungi in the workers' bedroom and station precincts were relatively high. No significant difference was found in the concentration of airborne bacteria and fungi between the underground and above ground activity areas of the subway. The genera identified in all subway activity areas with a 5% or greater detection rate were Staphylococcus, Micrococcus, Bacillus and Corynebacterium for airborne bacteria and Penicillium, Cladosporium, Chrysosporium, Aspergillus for airborne fungi. Staphylococcus and Micrococcus comprised over 50% of the total airborne bacteria and Penicillium and Cladosporium comprised over 60% of the total airborne fungi, thus these four genera are the predominant genera in the subway station.

  13. Fusion reactor high vacuum pumping: Charcoal cryosorber tritium exposure results

    SciTech Connect

    Sedgley, D.W.; Walthers, C.R.; Jenkins, E.M. )

    1991-01-01

    Recent experiments, have shown the practically of using activated charcoal (coconut charcoal) at 4{degrees}K to pump helium and hydrogen isotopes for a fusion reactor. Both speed and capacity for deuterium/helium and tritium/helium-3 mixtures were shown to be satisfactory. The long term effects of tritium on the charcoal/cement system developed by Grumman and LLNL were not known and a program was undertaken to see what, if any, effect long term tritium exposure has on the cryosorber. Several charcoal on aluminum test samples were subjected to six months exposure of tritium at approximately 77{degrees}K. The tritium was scanned several times with a residual gas analyzer and the speed-capacity performance of the samples was measured before, approximately half way through and after the exposure. Modest effects were noted which would not seriously restrict charcoal's use as a cryosorber for fusion reactor high vacuum pumping applications. 4 refs., 8 figs.

  14. Evaluation of High-Throughput Chemical Exposure Models ...

    EPA Pesticide Factsheets

    The U.S. EPA, under its ExpoCast program, is developing high-throughput near-field modeling methods to estimate human chemical exposure and to provide real-world context to high-throughput screening (HTS) hazard data. These novel modeling methods include reverse methods to infer parent chemical exposures from biomonitoring measurements and forward models to predict multi-pathway exposures from chemical use information and/or residential media concentrations. Here, both forward and reverse modeling methods are used to characterize the relationship between matched near-field environmental (air and dust) and biomarker measurements. Indoor air, house dust, and urine samples from a sample of 120 females (aged 60 to 80 years) were analyzed. In the measured data, 78% of the residential media measurements (across 80 chemicals) and 54% of the urine measurements (across 21 chemicals) were censored, i.e. below the limit of quantification (LOQ). Because of the degree of censoring, we applied a Bayesian approach to impute censored values for 69 chemicals having at least 15% of measurements above LOQ. This resulted in 10 chemicals (5 phthalates, 5 pesticides) with matched air, dust, and urine metabolite measurements. The population medians of indoor air and dust concentrations were compared to population median exposures inferred from urine metabolites concentrations using a high-throughput reverse-dosimetry approach. Median air and dust concentrations were found to be correl

  15. Non-ionic PAG behavior under high energy exposure sources

    NASA Astrophysics Data System (ADS)

    Lawson, Richard A.; Noga, David E.; Tolbert, Laren M.; Henderson, Clifford L.

    2009-03-01

    A series of non-ionic PAGs were synthesized and their acid generation efficiency measured under deep ultraviolet and electron beam exposures. The acid generation efficiency was determined with an on-wafer method that uses spectroscopic ellipsometry to measure the absorbance of an acid sensitive dye (Coumarin 6). Under DUV exposures, common ionic onium salt PAGs showed excellent photoacid generation efficiency, superior to most non-ionic PAGS tested in this work. In contrast, under 100 keV high energy e-beam exposures, almost all of the non-ionic PAGs showed significantly better acid generation performance than the ionic onium salt PAGs tested. In particular, one non-ionic PAG showed almost an order of magnitude improvement in the Dill C acid generation rate constant as compared to a triarylsulfonium PAG. The high energy acid generation efficiency was found to correlate well with the electron affinity of the PAGs, suggesting that improvements in PAG design can be predicted. Non-ionic PAGs merit further investigation as a means for producing higher sensitivity resists under high energy exposure sources.

  16. Parallel Processing at the High School Level.

    ERIC Educational Resources Information Center

    Sheary, Kathryn Anne

    This study investigated the ability of high school students to cognitively understand and implement parallel processing. Data indicates that most parallel processing is being taught at the university level. Instructional modules on C, Linux, and the parallel processing language, P4, were designed to show that high school students are highly…

  17. Effect of short-term ozone exposure on exogenous thyroxine levels in thyroidectomized and hypophysectomized rats

    SciTech Connect

    Clemons, G.K.; Wei, D.

    1984-06-15

    Short-term ozone exposure (1 ppm X 24 hr) of male rats results in a significant reduction of circulating thyroid hormones and thyroid stimulating hormone (TSH). The reduction of thyroid hormone levels after ozone exposure has been hypothesized as a possible adaptive mechanism to enhance survival of rats during ozone exposure. In this study, the authors investigated the effect of ozone on thyroid hormone (T4) levels in thyroidectomized and hypophysectomized rats which received exogenous T4 in the drinking water. Groups of normal, intact rats, thyroidectomized rats maintained on T4 at doses ranging from 75 to 1000 micrograms/liter, and hypophysectomized rats maintained on 300 micrograms T4/liter were exposed to ozone (1 ppm X 24 hr), Plasma T4 concentrations were significantly reduced after ozone exposure, and the results indicated that the higher the circulating T4 levels before exposure the more they were reduced after ozone exposure. This reduction in T4 levels cannot be accounted for in these animals by reduced pituitary TSH levels or the effects of fasting, but is likely to be due to peripheral changes in plasma thyroid binding proteins initiated by ozone exposure.

  18. High-Level Application Framework for LCLS

    SciTech Connect

    Chu, P; Chevtsov, S.; Fairley, D.; Larrieu, C.; Rock, J.; Rogind, D.; White, G.; Zalazny, M.; /SLAC

    2008-04-22

    A framework for high level accelerator application software is being developed for the Linac Coherent Light Source (LCLS). The framework is based on plug-in technology developed by an open source project, Eclipse. Many existing functionalities provided by Eclipse are available to high-level applications written within this framework. The framework also contains static data storage configuration and dynamic data connectivity. Because the framework is Eclipse-based, it is highly compatible with any other Eclipse plug-ins. The entire infrastructure of the software framework will be presented. Planned applications and plug-ins based on the framework are also presented.

  19. High-resolution simulations of the thermophysiological effects of human exposure to 100 MHz RF energy

    NASA Astrophysics Data System (ADS)

    Nelson, David A.; Curran, Allen R.; Nyberg, Hans A.; Marttila, Eric A.; Mason, Patrick A.; Ziriax, John M.

    2013-03-01

    Human exposure to radio frequency (RF) electromagnetic energy is known to result in tissue heating and can raise temperatures substantially in some situations. Standards for safe exposure to RF do not reflect bio-heat transfer considerations however. Thermoregulatory function (vasodilation, sweating) may mitigate RF heating effects in some environments and exposure scenarios. Conversely, a combination of an extreme environment (high temperature, high humidity), high activity levels and thermally insulating garments may exacerbate RF exposure and pose a risk of unsafe temperature elevation, even for power densities which might be acceptable in a normothermic environment. A high-resolution thermophysiological model, incorporating a heterogeneous tissue model of a seated adult has been developed and used to replicate a series of whole-body exposures at a frequency (100 MHz) which approximates that of human whole-body resonance. Exposures were simulated at three power densities (4, 6 and 8 mW cm-2) plus a sham exposure and at three different ambient temperatures (24, 28 and 31 °C). The maximum hypothalamic temperature increase over the course of a 45 min exposure was 0.28 °C and occurred in the most extreme conditions (Tamb = 31 °C, PD = 8 mW cm-2). Skin temperature increases attributable to RF exposure were modest, with the exception of a ‘hot spot’ in the vicinity of the ankle where skin temperatures exceeded 39 °C. Temperature increases in internal organs and tissues were small, except for connective tissue and bone in the lower leg and foot. Temperature elevation also was noted in the spinal cord, consistent with a hot spot previously identified in the literature.

  20. Levels and source apportionment of children's lead exposure: could urinary lead be used to identify the levels and sources of children's lead pollution?

    PubMed

    Cao, Suzhen; Duan, Xiaoli; Zhao, Xiuge; Wang, Beibei; Ma, Jin; Fan, Delong; Sun, Chengye; He, Bin; Wei, Fusheng; Jiang, Guibin

    2015-04-01

    As a highly toxic heavy metal, the pollution and exposure risks of lead are of widespread concern for human health. However, the collection of blood samples for use as an indicator of lead pollution is not always feasible in most cohort or longitudinal studies, especially those involving children health. To evaluate the potential use of urinary lead as an indicator of exposure levels and source apportionment, accompanying with environmental media samples, lead concentrations and isotopic measurements (expressed as (207)Pb/(206)Pb, (208)Pb/(206)Pb and (204)Pb/(206)Pb) were investigated and compared between blood and urine from children living in the vicinities of a typical coking plant and lead-acid battery factory. The results showed urinary lead might not be a preferable proxy for estimating blood lead levels. Fortunately, urinary lead isotopic measurements could be used as an alternative for identifying the sources of children's lead exposure, which coincided well with the blood lead isotope ratio analysis.

  1. Short-term high-altitude pre-exposure improves neurobehavioral ability

    PubMed Central

    Guo, Wenyun; Chen, Guozhu; Qin, Jun; Zhang, Jihang; Guo, Xubin; Yu, Jie; Song, Pan; Lu, Wei; Xu, Baida; Li, Jiabei; Ding, Xiaohan

    2016-01-01

    This study aims to evaluate the effect of the duration of high-altitude (HA) pre-exposure on human neurobehavioral parameters including mood states and cognitive performance at HA. One hundred and eleven healthy individuals (ranging in age from 18 to 35 years) were recruited to participate in this study. They were divided into two groups: a 4-day short-term HA pre-exposure group (n=57) and a 3-month long-term HA pre-exposure group (n=54). All participants lived in the area at 400 m altitude above sea level before pre-exposure to HA. They were then transported to 3700 m plateau for either a 4-day or a 3-month HA pre-exposure, and finally delivered to 4400 m plateau. On the last day of pre-exposure at 3700 m and on the 10th day at 4400 m, neurobehavioral parameters of the participants in the two groups were evaluated. At the end of pre-exposure and on the 10th day of HA exposure, participants in the short-term group had significantly lower negative mood states, better cognitive performance with higher sensorimotor, attention, and psychomotor abilities, and less acute mountain sickness in comparison with the participants in the long-term pre-exposure group. Our field study with large samples showed that in comparison with 3-month long-term pre-exposure, 4-day short-term HA pre-exposure at 3700 m has a better effect in improving human neurobehavioral parameters including mood states and cognitive performance and reducing acute mountain sickness when exposed to a HA at 4400 m. PMID:26966781

  2. Prenatal exposure to pesticides disrupts testicular histoarchitecture and alters testosterone levels in male Caiman latirostris.

    PubMed

    Rey, Florencia; González, Marianela; Zayas, Marcelo A; Stoker, Cora; Durando, Milena; Luque, Enrique H; Muñoz-de-Toro, Mónica

    2009-07-01

    The increased use of agrochemical pesticides, such as atrazine (ATZ) and endosulfan (END), may have a significant impact on ecosystem health and biodiversity. The aim of this study was to investigate the consequences of in ovum exposure to ATZ and END on Caiman latirostris gonadal histo-functional features. Caiman eggs were collected from environmentally pristine areas and incubated in controlled conditions at male producing temperature (33 degrees C). At stage 20 of embryonic development, the sensitive stage for gonadal sex determination, eggs were exposed to one dose of either END or ATZ. Gonadal histo-morphology was examined in caiman hatchlings and serum levels of testosterone were measured. Regardless of treatment condition, all eggs incubated at 33 degrees C resulted in male hatchlings. Tortuous seminiferous tubules with increased perimeter, disrupted distribution of peritubular myoid cells (desmin positive), and emptied tubular lumens characterized the testes of pesticide-exposed caiman. An imbalance between proliferative activity and cell death was observed in the testes of caiman exposed to the higher doses of END, mainly due to a high frequency of apoptosis in intratubular cells. This altered cell turnover was associated with decreased testosterone levels. Prenatal exposure to only one dose of END and ATZ disrupted neonatal male gonadal histo-functional features. Alterations described here could have detrimental effects on the sexual maturation of the caiman and, ultimately, on the success of male caiman reproduction.

  3. Increased levels of oxidative DNA damage attributable to cooking-oil fumes exposure among cooks.

    PubMed

    Ke, Yuebin; Cheng, Jinquan; Zhang, Zhicheng; Zhang, Renli; Zhang, Zhunzhen; Shuai, Zhihong; Wu, Tangchun

    2009-07-01

    Previous investigations have indicated that cooks are exposed to polycyclic aromatic hydrocarbons (PAHs) from cooking-oil fumes. However, Emission of PAH and their carcinogenic potencies from cooking oil fumes sources have not been investigated among cooks. To investigate the urinary excretion of a marker for oxidative DNA damage, 8-hydroxydeoxyguanosine (8-OHdG), in different groups of cooks and different exposure groups, and to study the association between 8-OHdG and 1-hydroxypyrene(1-OHP), a biological marker for PAH exposure. Urine samples were collected from different groups of cooks (n = 86) and from unexposed controls (n = 36); all were male with similar age and smoking habits. The health status, occupational history, smoking, and alcohol consumption 24 h prior to sampling was estimated from questionnaires. The urine samples were frozen for later analyses of 8-OHdG and 1-OHP levels by high-performance liquid chromatography. Excretion in urine of 8-OHdG was similar for controls (mean 1.2micromol/mol creatinine, n = 36), and for those who had been in the kitchen with an exhaust-hood operating (mean 1.5micromol/mol creatinine, n = 45). Cooks exposed to cooking-oil fumes without exhaust-hood operation had significantly increased excretion of 8-OHdG (mean 2.3micromol/mol creatinine, n = 18), compared with controls. The urinary levels of ln 1-OHP and ln 8-OHdG were still significantly correlated in a multiple regression analysis. The results indicate that exposure to PAH or possibly other compounds in cooking-oil fumes may cause oxidative DNA damage.

  4. Recent and long-term occupational noise exposure and salivary cortisol level.

    PubMed

    Stokholm, Zara Ann; Hansen, Åse Marie; Grynderup, Matias Brødsgaard; Bonde, Jens Peter; Christensen, Kent Lodberg; Frederiksen, Thomas Winther; Lund, Søren Peter; Vestergaard, Jesper Medom; Kolstad, Henrik Albert

    2014-01-01

    Environmental and occupational noise exposure have been related to increased risk of cardiovascular disease, hypothetically mediated by stress-activation of the hypothalamic-pituitary-adrenal (HPA) axis. The objective of this study was to investigate the relation between recent and long-term occupational noise exposure and cortisol level measured off work to assess a possible sustained HPA-axis effect. We included 501 industrial, finance, and service workers who were followed for 24h during work, leisure, and sleep. Ambient occupational noise exposure levels were recorded every 5s by personal dosimeters and we calculated the full-shift LAEq value and estimated duration and cumulative exposure based on their work histories since 1980. For 332 workers who kept a log-book on the use of hearing protection devices (HPD), we subtracted 10 dB from every noise recording obtained during HPD use and estimated the noise level at the ear. Salivary cortisol concentration was measured at 20.00 h, the following day at awakening, and 30 min after awakening on average 5, 14 and 14.5h after finishing work. The mean ambient noise exposure level was 79.9 dB(A) [range: 55.0-98.9] and the mean estimated level at the ear 77.7 dB(A) [range: 55.0-94.2]. In linear and mixed regression models that adjusted for age, sex, current smoking, heavy alcohol consumption, personal income, BMI, leisure-time noise exposure level, time since occupational noise exposure ceased, awakening time, and time of saliva sampling, we observed no statistically significant exposure response relation between recent, or long-term ambient occupational noise exposure level and any cortisol parameter off work. This was neither the case for recent noise level at the ear. To conclude, neither recent nor long-term occupational noise exposure levels were associated with increased cortisol level off work. Thus, our results do not indicate that a sustained activation of the HPA axis, as measured by cortisol, is involved in

  5. Extremely low-level microwaves attenuate immune imbalance induced by inhalation exposure to low-level toluene in mice.

    PubMed

    Novoselova, Elena G; Glushkova, Olga V; Khrenov, Maxim O; Novoselova, Tatyana V; Lunin, Sergey M; Fesenko, Eugeny E

    2017-05-01

    To clarify whether extremely low-level microwaves (MW) alone or in combination with p38 inhibitor affect immune cell responses to inhalation exposure of mice to low-level toluene. The cytokine profile, heat shock proteins expression, and the activity of several signal cascades, namely, NF-κB, SAPK/JNK, IRF-3, p38 MAPK, and TLR4 were measured in spleen lymphocytes of mice treated to air-delivered toluene (0.6 mg/m(3)) or extremely low-level microwaves (8.15-18 GHz, 1μW/cm(2), 1 Hz swinging frequency) or combined action of these two factors. A single exposure to air-delivered low-level toluene induced activation of NF-κB, SAPK/JNK, IFR-3, p38 MAPK and TLR4 pathways. Furthermore, air toluene induced the expression of Hsp72 and enhanced IL-1, IL-6, and TNF-α in blood plasma, which is indicative of a pro-inflammatory response. Exposure to MW alone also resulted in the enhancement of the plasma cytokine values (e.g. IL-6, TNF-α, and IFN-γ) and activation of the NF-κB, MAPK p38, and especially the TLR4 pathways in splenic lymphocytes. Paradoxically, pre-exposure to MW partially recovered or normalized the lymphocyte parameters in the toluene-exposed mice, while the p38 inhibitor XI additionally increased protective activity of microwaves by down regulating MAPKs (JNK and p38), IKK, as well as expression of TLR4 and Hsp90-α. The results suggest that exposure to low-intensity MW at specific conditions may recover immune parameters in mice undergoing inhalation exposure to low-level toluene via mechanisms involving cellular signaling.

  6. A Software Architecture for High Level Applications

    SciTech Connect

    Shen,G.

    2009-05-04

    A modular software platform for high level applications is under development at the National Synchrotron Light Source II project. This platform is based on client-server architecture, and the components of high level applications on this platform will be modular and distributed, and therefore reusable. An online model server is indispensable for model based control. Different accelerator facilities have different requirements for the online simulation. To supply various accelerator simulators, a set of narrow and general application programming interfaces is developed based on Tracy-3 and Elegant. This paper describes the system architecture for the modular high level applications, the design of narrow and general application programming interface for an online model server, and the prototype of online model server.

  7. Case hardenability at high carbon levels

    SciTech Connect

    Walton, H.W.

    1995-02-01

    Loss of hardenability in the case was thought to be responsible for a lower than specified hardness found on a large carburized bushing. Pseudo Jominy testing on several high hardenability carburizing grades confirmed that hardenability fade was present at carbon levels above 0.65% and particularly for those steels containing molybdenum. Analysis of previous work provided a formula for calculating Jominy hardenability at various carbon levels. Again the results confirmed that the loss of hardenability was more severe in steels containing molybdenum.

  8. Future high sea levels in south Sweden

    SciTech Connect

    Blomgren, S.H.; Hanson, H.

    1997-12-31

    An estimation of future mean high water levels in Oeresund and the southwest Baltic Sea is presented together with a discussion of probable consequences for Falsterbo Peninsula, a trumpet-shaped sandy formation of some 25 km{sup 2} size situated in the very southwest corner of Sweden. A literature review coupled with sea-level measurements and observations made in the area every four hours since October 1945 are given and comprise the base for the present analysis.

  9. Neighborhood disorder and telomeres: connecting children's exposure to community level stress and cellular response.

    PubMed

    Theall, Katherine P; Brett, Zoë H; Shirtcliff, Elizabeth A; Dunn, Erin C; Drury, Stacy S

    2013-05-01

    Our objective was to explore the utility of salivary telomere length (sTL) as an early indicator of neighborhood-level social environmental risk during child development. We therefore tested the hypothesis that sTL would be associated with markers of social stress exposure in children. Children age 4-14 from 87 neighborhoods were recruited through five urban schools in New Orleans, Louisiana, U.S. Data were collected at the level of the child, family/household, and neighborhood. DNA was obtained from saliva using commercially available kits and sTL was determined for 104 children using quantitative PCR. Analysis was performed on 99 children who had complete data including sTL, social environmental stress, and additional covariates. The mean sTL value was 7.4 T/S (telomere signal/single-copy signal) ratio units (±2.4, range = 2.5-18.0), and 4.7% of the variance in sTL was attributed to differences across neighborhoods. Children living in neighborhoods characterized by high disorder had an sTL value 3.2 units lower than children not living in high disordered environments (p < 0.05) and their odds of having low relative sTL (defined as <1 standard deviation below standardized Z-score mean) values was 3.43 times that of children not living in high disorder environments (adjusted OR = 3.43, 95% CI = 1.22, 9.62). Our findings are consistent with previous studies in adults demonstrating a strong link between psychosocial stress and sTL obtained from peripheral blood, consistent with previous studies in youth demonstrating an association between early life stress and sTL obtained from buccal cell DNA and offer increased support for the hypothesis that sTL represents a non-invasive biological indicator of psychosocial stress exposure (i.e., neighborhood disorder) able to reflect differences in stress exposure levels even in young children.

  10. Kinetic Stability of MOF-5 in Humid Environments: Impact of Powder Densification, Humidity Level, and Exposure Time.

    PubMed

    Ming, Yang; Purewal, Justin; Yang, Jun; Xu, Chunchuan; Soltis, Rick; Warner, James; Veenstra, Mike; Gaab, Manuela; Müller, Ulrich; Siegel, Donald J

    2015-05-05

    Metal-organic frameworks (MOFs) are an emerging class of microporous, crystalline materials with potential applications in the capture, storage, and separation of gases. Of the many known MOFs, MOF-5 has attracted considerable attention because of its ability to store gaseous fuels at low pressure with high densities. Nevertheless, MOF-5 and several other MOFs exhibit limited stability upon exposure to reactive species such as water. The present study quantifies the impact of humid air exposure on the properties of MOF-5 as a function of exposure time, humidity level, and morphology (i.e., powders vs pellets). Properties examined include hydrogen storage capacity, surface area, and crystallinity. Water adsorption/desorption isotherms are measured using a gravimetric technique; the first uptake exhibits a type V isotherm with a sudden increase in uptake at ∼50% relative humidity. For humidity levels below this threshold only minor degradation is observed for exposure times up to several hours, suggesting that MOF-5 is more stable than generally assumed under moderately humid conditions. In contrast, irreversible degradation occurs in a matter of minutes for exposures above the 50% threshold. Fourier transform infrared spectroscopy indicates that molecular and/or dissociated water is inserted into the skeletal framework after long exposure times. Densification into pellets can slow the degradation of MOF-5 significantly, and may present a pathway to enhance the stability of some MOFs.

  11. Analysis of the asbestos permissible-exposure-level threshold standard. Master's thesis

    SciTech Connect

    Peterson, M.W.

    1991-06-01

    This thesis examines the reasoning of the Occupational Safety and Health Administration's (OSHA) decision to set stringent exposure levels for airborne asbestos in the work place. Technical recommendations from the National Institute for Occupational Safety and Health (NIOSH), the Bureau of Mines, and the American conference of Governmental Industrial Hygienists were presented to OSHA for consideration. OSHA and the Environmental Protection Agency (EPA) set industry standards for permissible exposure levels (PEL) of airborne asbestos. Exposure to asbestos poses a health hazard to workers, their families, and consumers of asbestos products. Because it poses an unreasonable risk human life, OSHA has repeatedly lowered the Permissible Exposure Levels and the EPA will ban the manufacture, importation, processing and commercial distribution of asbestos containing products from the United States in phases by 1997. These decisions may have been made too hastily because of the long latency (15-40 years) period before cancer develops, and the added risks that smoking imposes.

  12. Survey of RF exposure levels from mobile telephone base stations in Australia.

    PubMed

    Henderson, S I; Bangay, M J

    2006-01-01

    This paper reports the results of an exposure level survey of radiofrequency electromagnetic energy originating from mobile telephone base station antennas. Measurements of CDMA800, GSM900, GSM1800, and 3G(UMTS) signals were performed at distances ranging over 50 to 500 m from 60 base stations in five Australian cities. The exposure levels from these mobile telecommunications base stations were found to be well below the general public exposure limits of the ICNIRP guidelines and the Australian radiofrequency standard (ARPANSA RPS3). The highest recorded level from a single base station was 7.8 x 10(-3) W/m(2), which translates to 0.2% of the general public exposure limit.

  13. Evaluation of RF electromagnetic field exposure levels from cellular base stations in Korea.

    PubMed

    Kim, Byung Chan; Park, Seong-Ook

    2010-09-01

    This article presents the measurement results of human exposure to CDMA800 and CDMA1800 signals at locations in Korea where the general public has expressed concern. Measurements were performed at 50 locations across the country to compare the electromagnetic field levels with the general public exposure compliance limits. At each site, the distances between the nearest single or co-located base station and measurement positions were within a range of approximately 32-422 m. The measured exposure levels were very low compared with the international standard and the Korean human protection notice. The highest field level was 1.5 V/m, which corresponds to 0.15% of the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines for human exposure. 2010 Wiley-Liss, Inc.

  14. Multi-exposure laser speckle contrast imaging using a high frame rate CMOS sensor with a field programmable gate array.

    PubMed

    Sun, Shen; Hayes-Gill, Barrie R; He, Diwei; Zhu, Yiqun; Morgan, Stephen P

    2015-10-15

    A system has been developed in which multi-exposure laser speckle contrast imaging (LSCI) is implemented using a high frame rate CMOS imaging sensor chip. Processing is performed using a field programmable gate array (FPGA). The system allows different exposure times to be simulated by accumulating a number of short exposures. This has the advantage that the image acquisition time is limited by the maximum exposure time and that regulation of the illuminating light level is not required. This high frame rate camera has also been deployed to implement laser Doppler blood flow processing, enabling a direct comparison of multi-exposure laser speckle imaging and laser Doppler imaging (LDI) to be carried out using the same experimental data. Results from a rotating diffuser indicate that both multi-exposure LSCI and LDI provide a linear response to changes in velocity. This cannot be obtained using single-exposure LSCI, unless an appropriate model is used for correcting the response.

  15. Secondhand Smoke Exposure Levels in Outdoor Hospitality Venues: A Qualitative and Quantitative Review of the Research Literature

    PubMed Central

    LICHT, ANDREA S; HYLAND, ANDREW; TRAVERS, MARK J; CHAPMAN, SIMON

    2013-01-01

    Objective This paper considers the evidence on whether outdoor secondhand smoke (SHS) is present in high enough levels of hospitality venues to potentially pose health risks, particularly among employees of such establishments. Data Sources Search strings in PubMed and Web of Science included combinations of environmental tobacco smoke, secondhand smoke, or passive smoke AND outdoor, yielding 217 and 5,199 results, respectively through June, 2012. Study Selection Sixteen studies were selected based on abstract review that either entirely or partly measured outdoor SHS exposures (particulate matter (PM) or other SHS indicators). Data Extraction The methods used to measure SHS indicators, particularly PM, were assessed for inclusion of extraneous variables that may affect such measurements or the corroboration of ambient levels with known standards. Data Synthesis The magnitude of SHS exposure (PM2.5) is dependent on the number of smokers present, proximity to the measuring device, outdoor enclosures, and wind. Under specific conditions, peak outdoor PM2.5 levels can be comparable to those recorded in indoor smoky environments. Using data from both observational and experimental studies, annual excess PM2.5 exposure of full-time waitstaff at outdoor smoking environments could average 4.0 to 12.2 μg/m3 under variable smoking conditions. Conclusions Although highly transitory, outdoor SHS exposures could occasionally exceed annual ambient air quality exposure guidelines. However, such exposures are likely to be higher for occupationally exposed individuals compared to patrons due to repeated and cumulative outdoor SHS exposures. Personal monitoring studies of waitstaff are warranted to corroborate these modeled estimates. PMID:23220937

  16. Comparison of screening-level and Monte Carlo approaches for wildlife food web exposure modeling

    SciTech Connect

    Pastorok, R.; Butcher, M.; LaTier, A.; Ginn, T.

    1995-12-31

    The implications of using quantitative uncertainty analysis (e.g., Monte Carlo) and site-specific tissue residue data for wildlife exposure modeling were examined with data on trace elements at the Clark Fork River Superfund Site. Exposure of white-tailed deer, red fox, and American kestrel was evaluated using three approaches. First, a screening-level exposure model was based on conservative estimates of exposure parameters, including estimates of dietary residues derived from bioconcentration factors (BCFs) and soil chemistry. A second model without Monte Carlo was based on site-specific data for tissue residues of trace elements (As, Cd, Cu, Pb, Zn) in key dietary species and plausible assumptions for habitat spatial segmentation and other exposure parameters. Dietary species sampled included dominant grasses (tufted hairgrass and redtop), willows, alfalfa, barley, invertebrates (grasshoppers, spiders, and beetles), and deer mice. Third, the Monte Carlo analysis was based on the site-specific residue data and assumed or estimated distributions for exposure parameters. Substantial uncertainties are associated with several exposure parameters, especially BCFS, such that exposure and risk may be greatly overestimated in screening-level approaches. The results of the three approaches are compared with respect to realism, practicality, and data gaps. Collection of site-specific data on trace elements concentrations in plants and animals eaten by the target wildlife receptors is a cost-effective way to obtain realistic estimates of exposure. Implications of the results for exposure and risk estimates are discussed relative to use of wildlife exposure modeling and evaluation of remedial actions at Superfund sites.

  17. Occupational EMF exposure from radar at X and Ku frequency band and plasma catecholamine levels.

    PubMed

    Singh, Sarika; Kapoor, Neeru

    2015-09-01

    Workers in certain occupations such as the military may be exposed to technical radiofrequency radiation exposure above current limits, which may pose a health risk. The present investigation intended to find the effect of chronic electromagnetic field (EMF) exposure from radar on plasma catecholamines in the military workforce. In the study, 166 male personnel selected randomly were categorized into three groups: control (n = 68), exposure group-I (X-band, 8-12 GHz, n = 40), and exposure group-II (Ku-band, 12.5-18 GHz, n = 58). The three clusters were further divided into two groups according to their years of service (YOS) (up to 9 years and ≥10 years) to study the effect of years of radar exposure. Enzyme immunoassay was employed to assess catecholamine concentrations. EMF levels were recorded at different occupational distances from radar. Significant adrenaline diminution was registered in exposure group-II with no significant difference in exposure group-I when both groups were weighed against control. Nor-adrenaline and dopamine levels did not vary significantly in both exposure groups when compared to controls. Exposure in terms of YOS also did not yield any significant alteration in any of the catecholamines and in any of the exposure groups when compared with their respective control groups. The shift from baseline catecholamine values due to stress has immense significance for health and well-being. Their continual alteration may prove harmful in due course. Suitable follow-up studies are needed to further strengthen these preliminary observations and for now, exposures should be limited as much as possible with essential safeguards.

  18. Chronic exposure in vivo to thyrotropin receptor stimulating monoclonal antibodies sustains high thyroxine levels and thyroid hyperplasia in thyroid autoimmunity-prone HLA-DRB1*0301 transgenic mice

    PubMed Central

    Flynn, Jeffrey C; Gilbert, Jacqueline A; Meroueh, Chady; Snower, Daniel P; David, Chella S; Kong, Yi-chi M; Paul Banga, J

    2007-01-01

    We have examined the induction of autoimmunity and the maintenance of sustained hyperthyroidism in autoimmunity-prone human leucocyte antigen (HLA) DR3 transgenic non-obese diabetic (NOD) mice following chronic stimulation of the thyrotropin receptor (TSHR) by monoclonal thyroid-stimulating autoantibodies (TSAbs). Animals received weekly injections over the course of 9 weeks of monoclonal antibodies (mAbs) with strong thyroid-stimulating properties. Administration of the mAbs KSAb1 (IgG2b) or KSAb2 (IgG2a), which have similar stimulating properties but different TSH-binding blocking activity, resulted in significantly elevated serum thyroxine (T4) levels and thyroid hyperplasia. After the first injection, an initial surge then fall in serum T4 levels was followed by sustained elevated levels with subsequent injections for at least 63 days. Examination of KSAb1 and KSAb2 serum bioactivity showed that the accumulation of the TSAbs in serum was related to their subclass half-lives. The thyroid glands were enlarged and histological examination showed hyperplastic follicles, with minimal accompanying thyroid inflammation. Our results show that chronic in vivo administration of mAbs with strong thyroid-stimulating activity resulted in elevated T4 levels, suggesting persistent stimulation without receptor desensitization, giving a potential explanation for the sustained hyperthyroid status in patients with Graves' disease. Moreover, despite the presence of HLA disease susceptibility alleles and the autoimmune prone NOD background genes, chronic stimulation of the thyroid gland did not lead to immune cell-mediated follicular destruction, suggesting the persistence of immunoregulatory influences to suppress autoimmunity. PMID:17535305

  19. Airborne exposure and soil levels associated with lead abatement of a steel tank.

    PubMed

    Lange, John H

    2002-02-01

    This study reports on airborne exposure levels and soil concentrations of lead in regard to abatement of a steel structure (water tank). The tank was de-leaded by abrasive sand blasting. The ball of the tank had a lead surface level that exceeded the Environmental Protection Agency (EPA) definition of lead-based paint (LBP) (0.5% lead), but paint on stem and base was below this criterion. Personal and area airborne samples were collected during different activities of lead abatement of the tank. Summary results suggest during abrasive blasting of ball and stem/base personal exposure levels, as reported with arithmetic and geometric means, exceed the Occupational Safety and Health Administration (OSHA) permissible exposure limit (50 microg/m3). Highest personal exposure (occupational exposure) was associated with blasting of ball. Distribution of airborne and soil samples suggest non-normality and is best represented by a logarithmic form. Geometric standard deviations for air and soil lead support a non-normal distribution. Outlying values were found for personal and area air samples. Exposure levels associated with blasting stem/base section of tank support OSHA's policy requiring air monitoring of work at levels below the criterion established by EPA in identifying LBP. Area samples were statistically lower than personal samples associated with blasting ball and stem/base of tank. Exposure data suggest that workers performing abatement on steel structures have elevated lead exposure from surface lead. Respirator protection requirements are discussed. Soil lead concentration was suggested to decrease as distance increased from tank. Soil lead is suggested to be a result of deposition from LBP on tank surface. Minimal efforts were required to reduce average lead soil levels below EPA's upper acceptable criterion (1200 ppm Pb).

  20. Ultraviolet radiation exposure and serum vitamin D levels in young children.

    PubMed

    Ramankutty, Padmaja; de Klerk, Nicholas H; Miller, Margaret; Fenech, Michael; O'Callaghan, Nathan; Armstrong, Bruce K; Milne, Elizabeth

    2014-09-01

    Health benefits of adequate vitamin D levels in the blood include better bone health and a reduced incidence of a range of chronic diseases and infections. Ultraviolet (UV) radiation exposure from the sun is the main source of vitamin D; however, such exposure, especially from a young age, is also a potential risk factor for skin cancer. The current study examined the association of UV exposure with vitamin D production in young children to determine the period of weekly exposure prior to blood testing that affected serum 25-hydroxyvitamin D (25(OH)D) levels. Between 2009 and 2011, healthy children aged 3, 6 and 9 years were recruited from the community for a cross-sectional study of nutritional factors and DNA damage. Parents of 464 children provided information on the children's average weekly sun exposure and level of sun protection during each of the 16 weeks before blood sample collection by a domiciliary phlebotomist. Serum 25(OH)D levels were best predicted from UV exposure during the week before blood collection for samples drawn in autumn, summer or spring. For samples drawn in winter, serum 25(OH)D levels were best predicted by UV exposure during the 2 weeks before blood collection. Consistent weekly sun exposure may be beneficial for young children, especially in winter, to maintain healthy vitamin D levels in the blood. However, confirmation of these results is needed before their public health significance can be fully evaluated. © 2014 The Authors. Journal of Paediatrics and Child Health © 2014 Paediatrics and Child Health Division (Royal Australasian College of Physicians).

  1. Microcosm procedure for determining safe levels of chemical exposure in shallow-water communities

    SciTech Connect

    Giddings, J.M.

    1985-01-01

    This paper describes a method for determining safe levels of chemical exposure in shallow-water communities, using laboratory microcosms as test subjects. The safe level is considered to be the maximum exposure that causes no persistent, ecologically significant changes in the ecosystem. In experiments completed at Oak Ridge National Laboratory, microcosm-derived estimates of safe exposure levels were confirmed using outdoor artificial ponds, which suggests that the microcosm procedure can be an efficient and economical means of determining safe levels for shallow-water communities. Details of microcosm construction, techniques for monitoring ecological variables in microcosms, and an experimental design for determining safe exposure levels are provided here. The microcosms are assembled by transferring components of natural ecosystems to 80-litre aquaria in a controlled laboratory environment. The communities that develop in these systems are typically dominated by common, cosmopolitan littoral species of macrophytes, algae, and invertebrates. Methods are described for measuring changes in water chemistry, phytoplankton, periphyton, macrophytes, zooplankton, and ecosystem production and respiration. By monitoring these variables over a gradient of pollutant exposure levels, the safe level can be determined accurately and precisely. 16 refs., 2 figs.

  2. Chernobyl exposure as stressor during pregnancy and hormone levels in adolescent offspring

    PubMed Central

    Huizink, AC; Bartels, M; Rose, RJ; Pulkkinen, L; Eriksson, CJP; Kaprio, J

    2007-01-01

    Background Animal research suggests a programming effect of prenatal stress in the fetal period, resulting in disruptions in behavioral and neuromotor development. Physiological changes that mediate these effects include alterations in the hypothalamic-pituitary-adrenal axis and in testosterone levels. This human study focuses on changes related to these physiological systems after prenatal stress exposure. Methods We examined the potential effect of prenatal stress associated with the Chernobyl disaster in an ongoing genetic epidemiological study in Finland. One birth cohort of twins (n= 121 twin pairs) was exposed in utero to maternal stress, and their saliva cortisol and testosterone levels at age 14 were compared with twins (n = 157 twin pairs) born one year later. Results Cortisol levels in both sexes and testosterone levels among females were significantly elevated after prenatal exposure to maternal stress from the second trimester onwards, compared to reference groups of non-exposed adolescents. Exposure explains 3 percent of variance (p<0.05) in cortisol levels and 18 percent of variance in testosterone levels (p< 0.001). No significant differences were found for exposure from either first or third trimester onwards. Conclusion Our results suggest that prenatal exposure to maternal stress in the second trimester of pregnancy may have resulted in prenatal programming of physiological systems relating to cortisol and testosterone levels. PMID:18365332

  3. High exposures to organic solvents among graffiti removers.

    PubMed

    Anundi, H; Lind, M L; Friis, L; Itkes, N; Langworth, S; Edling, C

    1993-01-01

    The exposure to organic solvents among 12 graffiti removers was studied. Health effects were also assessed by structured interview and a symptom questionnaire. Blood and urine samples were collected at the end of the day of air sampling. The concentrations of dichloromethane, glycol ethers, trimethylbenzenes and N-methyl-2-pyrrolidinone in the breathing zone of each worker were measured during one working day. The 8-h time-weighted average exposure to dichloromethane ranged from 18 to 1200 mg/m3. The Swedish Permissible Exposure Limit value for dichloromethane is 120 mg/m3. The air concentrations of glycol ethers, trimethylbenzenes and N-methyl-2-pyrrolidinone were low or not detectable. No exposure-related deviations in the serum concentrations of creatinine, aspartate transaminase, alanine transaminase, gamma-glutamyl transpeptidase or hyaluronan or the urine concentrations of alpha 1-microglobulin, beta 2-microglobulin or N-acetyl-beta-glucosaminidase were found. Irritative symptoms of the eyes and upper respiratory tract were more prevalent than in the general population. This study demonstrates that old knowledge about work hazards is not automatically transferred to new professions. Another aspect is that the public is also exposed as the job is performed during daytime in underground stations. At least for short periods, bystanders may be exposed to high concentrations of organic solvent vapours. People with predisposing conditions, e.g. asthmatics, may risk adverse reactions.

  4. High exposure to endotoxin in farming is associated with less new-onset pollen sensitisation.

    PubMed

    Elholm, Grethe; Schlünssen, Vivi; Doekes, Gert; Basinas, Ioannis; Bolund, Anneli Clea Skjelmose; Hjort, Charlotte; Grønager, Pernille Milvang; Omland, Øyvind; Sigsgaard, Torben

    2017-08-23

    Little is known about risk factors for new onset and loss of atopic sensitisation in adulthood. The aim is to examine the longitudinal effect of quantitatively assessed endotoxin exposures on changes in specific allergen sensitisation in young adults. The cohort consisted of 1113 young Danish farmers and rural controls, with a mean age of 19 years at baseline. Sensitisation to birch pollen, grass pollen, cat dander and house dust mite was measured by specific IgE levels in serum samples from baseline and at 15 years' follow-up. Changes in sensitisation were analysed in relation to cumulative endotoxin exposure during follow-up, considering early life farm exposure. Endotoxin exposure during follow-up was significantly associated with less new onset of specifically grass and birch pollen sensitisation. For the highest versus lowest quartile of cumulative endotoxin exposure, the OR for new-onset IgE sensitisation was 0.35 (0.13-0.91) for birch and 0.14 (0.05-0.50) for grass. On the other hand, loss of pollen sensitisation showed a positive, although mostly non-significant, association with increased levels of endotoxin exposure. Endotoxin exposure was not associated with significant changes in cat dander and house dust mite sensitisation. High exposure to endotoxin during young adulthood appears to protect against new onset of pollen sensitisation, independent of childhood farm exposure. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  5. High-level radioactive wastes. Supplement 1

    SciTech Connect

    McLaren, L.H.

    1984-09-01

    This bibliography contains information on high-level radioactive wastes included in the Department of Energy's Energy Data Base from August 1982 through December 1983. These citations are to research reports, journal articles, books, patents, theses, and conference papers from worldwide sources. Five indexes, each preceded by a brief description, are provided: Corporate Author, Personal Author, Subject, Contract Number, and Report Number. 1452 citations.

  6. PAIRWISE BLENDING OF HIGH LEVEL WASTE (HLW)

    SciTech Connect

    CERTA, P.J.

    2006-02-22

    The primary objective of this study is to demonstrate a mission scenario that uses pairwise and incidental blending of high level waste (HLW) to reduce the total mass of HLW glass. Secondary objectives include understanding how recent refinements to the tank waste inventory and solubility assumptions affect the mass of HLW glass and how logistical constraints may affect the efficacy of HLW blending.

  7. Do we understand high-level vision?

    PubMed

    Cox, David Daniel

    2014-04-01

    'High-level' vision lacks a single, agreed upon definition, but it might usefully be defined as those stages of visual processing that transition from analyzing local image structure to analyzing structure of the external world that produced those images. Much work in the last several decades has focused on object recognition as a framing problem for the study of high-level visual cortex, and much progress has been made in this direction. This approach presumes that the operational goal of the visual system is to read-out the identity of an object (or objects) in a scene, in spite of variation in the position, size, lighting and the presence of other nearby objects. However, while object recognition as a operational framing of high-level is intuitive appealing, it is by no means the only task that visual cortex might do, and the study of object recognition is beset by challenges in building stimulus sets that adequately sample the infinite space of possible stimuli. Here I review the successes and limitations of this work, and ask whether we should reframe our approaches to understanding high-level vision. Copyright © 2014. Published by Elsevier Ltd.

  8. Long-Term Exposure to High Altitude Affects Conflict Control in the Conflict-Resolving Stage.

    PubMed

    Ma, Hailin; Wang, Yan; Wu, Jianhui; Wang, Baoxi; Guo, Shichun; Luo, Ping; Han, Buxin

    2015-01-01

    The neurocognitive basis of the effect of long-term high altitude exposure on conflict control is unclear. Event related potentials (ERPs) were recorded in a flanker task to investigate the influence of high altitude on conflict control in the high-altitude group (who had lived at high altitude for three years but were born at low altitude) and the low-altitude group (living in low altitude only). Although altitude effect was not significant at the behavioral level, ERPs showed cognitive conflict modulation. The interaction between group and trial type was significant: P3 amplitude was greater in the low-altitude group than in the high-altitude group in the incongruent trial. This result suggests that long-term exposure to high altitude affects conflict control in the conflict-resolving stage, and that attentional resources are decreased to resist the conflict control in the high-altitude group.

  9. Long-Term Exposure to High Altitude Affects Conflict Control in the Conflict-Resolving Stage

    PubMed Central

    Wu, Jianhui; Wang, Baoxi; Guo, Shichun; Luo, Ping; Han, Buxin

    2015-01-01

    The neurocognitive basis of the effect of long-term high altitude exposure on conflict control is unclear. Event related potentials (ERPs) were recorded in a flanker task to investigate the influence of high altitude on conflict control in the high-altitude group (who had lived at high altitude for three years but were born at low altitude) and the low-altitude group (living in low altitude only). Although altitude effect was not significant at the behavioral level, ERPs showed cognitive conflict modulation. The interaction between group and trial type was significant: P3 amplitude was greater in the low-altitude group than in the high-altitude group in the incongruent trial. This result suggests that long-term exposure to high altitude affects conflict control in the conflict-resolving stage, and that attentional resources are decreased to resist the conflict control in the high-altitude group. PMID:26671280

  10. The High-Throughput Stochastic Human Exposure and Dose Simulation Model (SHEDS-HT) & The Chemical and Products Database (CPDat)

    EPA Science Inventory

    The Stochastic Human Exposure and Dose Simulation Model – High-Throughput (SHEDS-HT) is a U.S. Environmental Protection Agency research tool for predicting screening-level (low-tier) exposures to chemicals in consumer products. This course will present an overview of this m...

  11. The High-Throughput Stochastic Human Exposure and Dose Simulation Model (SHEDS-HT) & The Chemical and Products Database (CPDat)

    EPA Science Inventory

    The Stochastic Human Exposure and Dose Simulation Model – High-Throughput (SHEDS-HT) is a U.S. Environmental Protection Agency research tool for predicting screening-level (low-tier) exposures to chemicals in consumer products. This course will present an overview of this m...

  12. The Impact of Different Permissible Exposure Limits on Hearing Threshold Levels Beyond 25 dBA

    PubMed Central

    Sayapathi, Balachandar S; Su, Anselm Ting; Koh, David

    2014-01-01

    Background: Development of noise-induced hearing loss is reliant on a few factors such as frequency, intensity, and duration of noise exposure. The occurrence of this occupational malady has doubled from 120 million to 250 million in a decade. Countries such as Malaysia, India, and the US have adopted 90 dBA as the permissible exposure limit. According to the US Occupational Safety and Health Administration (OSHA), the exposure limit for noise is 90 dBA, while that of the US National Institute of Occupational Safety and Health (NIOSH) is 85 dBA for 8 hours of noise exposure. Objectives: This study aimed to assess the development of hearing threshold levels beyond 25 dBA on adoption of 85 dBA as the permissible exposure limit compared to 90 dBA. Patients and Methods: This is an intervention study done on two automobile factories. There were 203 employees exposed to noise levels beyond the action level. Hearing protection devices were distributed to reduce noise levels to a level between the permissible exposure limit and action level. The permissible exposure limits were 90 and 85 dBA in factories 1 and 2, respectively, while the action levels were 85 and 80 dBA, respectively. The hearing threshold levels of participants were measured at baseline and at first month of postshift exposure of noise. The outcome was measured by a manual audiometer. McNemar and chi-square tests were used in the statistical analysis. Results: We found that hearing threshold levels of more than 25 dBA has changed significantly from pre-intervention to post-intervention among participants from both factories (3000 Hz for the right ear and 2000 Hz for the left ear). There was a statistically significant association between participants at 3000 Hz on the right ear at ‘deteriorated’ level ( χ² (1) = 4.08, φ = - 0.142, P = 0.043), whereas there was worsening of hearing threshold beyond 25 dBA among those embraced 90 dBA. Conclusions: The adoption of 85 dBA as the permissible exposure

  13. Secondhand smoke exposure levels in outdoor hospitality venues: a qualitative and quantitative review of the research literature.

    PubMed

    Licht, Andrea S; Hyland, Andrew; Travers, Mark J; Chapman, Simon

    2013-05-01

    This paper considers the evidence on whether outdoor secondhand smoke (SHS) is present in hospitality venues at high levels enough to potentially pose health risks, particularly among employees. Searches in PubMed and Web of Science included combinations of environmental tobacco smoke, secondhand smoke, or passive smoke AND outdoor, yielding 217 and 5,199 results, respectively through June, 2012. Sixteen studies were selected that reported measuring any outdoor SHS exposures (particulate matter (PM) or other SHS indicators). The SHS measurement methods were assessed for inclusion of extraneous variables that may affect levels or the corroboration of measurements with known standards. The magnitude of SHS exposure (PM2.5) depends on the number of smokers present, measurement proximity, outdoor enclosures, and wind. Annual excess PM2.5 exposure of full-time waitstaff at outdoor smoking environments could average 4.0 to 12.2 μg/m3 under variable smoking conditions. Although highly transitory, outdoor SHS exposures could occasionally exceed annual ambient air quality exposure guidelines. Personal monitoring studies of waitstaff are warranted to corroborate these modeled estimates.

  14. Biochemical responses and metals levels in Ruditapes decussatus after exposure to treated municipal effluents.

    PubMed

    Kamel, Naouel; Jebali, Jamel; Banni, Mohamed; Ben Khedher, Sana; Chouba, Lassaad; Boussetta, Hamadi

    2012-08-01

    This study assessed the responses of biochemical biomarkers and metals levels in Ruditapes decussatus exposed to the increasing concentrations of treated municipal effluents (TME) discharged into the Tunisian coastal area. Clams were exposed to 0%, 1%, 3% and 10% for 7 and 14 day and the following biochemical responses were measured: (1) catalase activity and lipid peroxidation levels (TBARS) as oxidative stress biomarkers, (2) gluthathione S-transferase (GST) activity as a phase II conjugation enzyme; (3) cholinesterase activity (ChE) as biomarker of neurotoxicity, and (4) metallothioneins as a proteins highly induced by heavy metals. A significant uptake of Cu, Cd and Zn in digestive gland and serious biochemical alterations were observed. Thus, exposure of clams to croissant concentration of TME have the potential to increase the oxidative stress biomarkers (TBARS, CAT activity) and MT levels; and decrease ChE activity in both gills and digestive gland. Current experimental results suggest that CAT, GST, ChE activities and MT and TBARs levels in gills and digestive gland of clam R. decussatus are sensitive and suitable responses for assessing the effects of anthropogenic contaminants on the aquatic ecosystems, particularly effluent complex mixtures.

  15. Consequences of brief exposure to high concentrations of carbon monoxide in conscious rats.

    PubMed

    Gu, Zengfa; Januszkiewicz, Adolph J; Mayorga, Maria A; Coleman, Gary D; Morrissette, Craig R

    2005-12-01

    Exposure to high-concentration carbon monoxide (CO) is of concern in military operations. Experimentally, the physiologic manifestations of a brief exposure to elevated levels of CO have not been fully described. This study investigated the development of acute CO poisoning in conscious male Sprague-Dawley rats (220-380 g). Animals were randomly grouped (n = 6) and exposed to either air or 1 of 6 CO concentrations (1000, 3000, 6000, 10,000, 12,000, or 24,000 ppm) in a continuous air/CO dynamic exposure chamber for 5 min. Respiration was recorded prior to and during exposures. Mixed blood carboxyhemoglobin (COHb) and pH were measured before and immediately after exposure. Before exposure the mean baselines of respiratory minute volumes (RMVs) were 312.6 +/- 43.9, 275.2 +/- 40.8, and 302.3 +/- 39.1 ml/min for the 10,000, 12,000 and 24,000 ppm groups, respectively. In the last minute of exposure RMVs were 118.9 +/- 23.7, 62.1 +/- 10.4, and 22.0 +/- 15.1% (p < .05) of their mean baselines in these 3 groups, respectively. Immediately after exposure, blood COHb saturations were elevated to 60.16, 63.42, and 69.37%, and blood pH levels were reduced to 7.43 +/- 0.09, 7.25 +/- 0.05, and 7.13 +/- 0.04 in the 3 groups, respectively. Mortality during exposure was 1/12 in the 12,000 ppm group and 4/12 in the 24,000 ppm group. Deaths occurred close to the end of 5 min exposure. In each animal that died by exposure, pH was <6.87 and COHb saturation was >82%. Blood pH was unaltered and no death occurred in rats exposed to CO at concentrations <6000 ppm, although COHb saturations were elevated to 14.52, 29.94, and 57.24% in the 1000, 3000, and 6000 ppm groups, respectively. These results suggest that brief exposure to CO at concentrations <10,000 ppm may produce some significant physiological changes. However, exposure to CO at concentrations >10,000 ppm for brief periods as short as 5 min may change RMV, resulting in acute respiratory failure, acidemia, and even death.

  16. Epidemiology and impact of Fasciola hepatica exposure in high-yielding dairy herds.

    PubMed

    Howell, Alison; Baylis, Matthew; Smith, Rob; Pinchbeck, Gina; Williams, Diana

    2015-09-01

    The liver fluke Fasciola hepatica is a trematode parasite with a worldwide distribution and is the cause of important production losses in the dairy industry. The aim of this observational study was to assess the prevalence of exposure to F. hepatica in a group of high yielding dairy herds, to determine the risk factors and investigate their associations with production and fertility parameters. Bulk milk tank samples from 606 herds that supply a single retailer with liquid milk were tested with an antibody ELISA for F. hepatica. Multivariable linear regression was used to investigate the effect of farm management and environmental risk factors on F. hepatica exposure. Higher rainfall, grazing boggy pasture, presence of beef cattle on farm, access to a stream or pond and smaller herd size were associated with an increased risk of exposure. Univariable regression was used to look for associations between fluke exposure and production-related variables including milk yield, composition, somatic cell count and calving index. Although causation cannot be assumed, a significant (p<0.001) negative association was seen between F. hepatica exposure and estimated milk yield at the herd level, representing a 15% decrease in yield for an increase in F. hepatica exposure from the 25th to the 75th percentile. This remained significant when fertility, farm management and environmental factors were controlled for. No associations were found between F. hepatica exposure and any of the other production, disease or fertility variables.

  17. Epidemiology and impact of Fasciola hepatica exposure in high-yielding dairy herds

    PubMed Central

    Howell, Alison; Baylis, Matthew; Smith, Rob; Pinchbeck, Gina; Williams, Diana

    2015-01-01

    The liver fluke Fasciola hepatica is a trematode parasite with a worldwide distribution and is the cause of important production losses in the dairy industry. The aim of this observational study was to assess the prevalence of exposure to F. hepatica in a group of high yielding dairy herds, to determine the risk factors and investigate their associations with production and fertility parameters. Bulk milk tank samples from 606 herds that supply a single retailer with liquid milk were tested with an antibody ELISA for F. hepatica. Multivariable linear regression was used to investigate the effect of farm management and environmental risk factors on F. hepatica exposure. Higher rainfall, grazing boggy pasture, presence of beef cattle on farm, access to a stream or pond and smaller herd size were associated with an increased risk of exposure. Univariable regression was used to look for associations between fluke exposure and production-related variables including milk yield, composition, somatic cell count and calving index. Although causation cannot be assumed, a significant (p < 0.001) negative association was seen between F. hepatica exposure and estimated milk yield at the herd level, representing a 15% decrease in yield for an increase in F. hepatica exposure from the 25th to the 75th percentile. This remained significant when fertility, farm management and environmental factors were controlled for. No associations were found between F. hepatica exposure and any of the other production, disease or fertility variables. PMID:26093971

  18. Levels of preservatives (sulfite, sorbate and benzoate) in New Zealand foods and estimated dietary exposure.

    PubMed

    Cressey, P; Jones, S

    2009-05-01

    Thirty foods assessed as being the likely major contributors to dietary preservative exposure were purchased, prepared as normally consumed and analyzed for sulfite, sorbate and benzoate. The majority of preservative concentrations (>98%) were within maximum permitted levels (MPLs) specified in the Australia New Zealand Food Standards Code. Mean population level estimates of dietary exposure were well below the respective acceptable daily intakes (ADIs) for all age-gender groups for all preservatives at 7-27%, 1-4% and 1-8% of the ADI for sulfites, sorbates and benzoates, respectively. All population level 95th percentile estimates of dietary exposure were below the ADI, with the exception of estimates for sulfite exposure for 5-12-year-old boys. The results of the current survey indicate that dietary exposure to the preservatives, sulfite, sorbate and benzoate, represent a low level of public health risk. However, it should be noted that the exposure estimates determined in the current survey will be influenced by the assumptions made.

  19. OPERATOR DEPENDENCY OF THE RADIATION EXPOSURE IN CARDIAC INTERVENTIONS: FEASIBILITY OF ULTRA LOW DOSE LEVELS.

    PubMed

    Ozpelit, Mehmet Emre; Ercan, Ertugrul; Ozpelit, Ebru; Pekel, Nihat; Tengiz, Istemihan; Ozyurtlu, Ferhat; Yilmaz, Akar

    2017-04-15

    Mean radiation exposure in invasive cardiology varies greatly between different centres and interventionists. The International Commission on Radiological Protection and the EURATOM Council stipulate that, despite reference values, 'All medical exposure for radiodiagnostic purposes shall be kept as low as reasonably achievable' (ALARA). The purpose of this study is to establish the effects of the routine application of ALARA principles and to determine operator and procedure impact on radiation exposure in interventional cardiology. A total of 240 consecutive cardiac interventional procedures were analysed. Five operators performed the procedures, two of whom were working in accordance with ALARA principles (Group 1 operators) with the remaining three working in a standard manner (Group 2 operators). Radiation exposure levels of these two groups were compared. Total fluoroscopy time and the number of radiographic runs were similar between groups. However, dose area product and cumulative dose were significantly lower in Group 1 when compared with Group 2. Radiation levels of Group 1 were far below even the reference levels in the literature, thus representing an ultra-low-dose radiation exposure in interventional cardiology. By use of simple radiation reducing techniques, ultra-low-dose radiation exposure is feasible in interventional cardiology. Achievability of such levels depends greatly on operator awareness, desire, knowledge and experience of radiation protection. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  20. Area-level socioeconomic deprivation, nitrogen dioxide exposure, and term birth weight in New York City.

    PubMed

    Shmool, Jessie L C; Bobb, Jennifer F; Ito, Kazuhiko; Elston, Beth; Savitz, David A; Ross, Zev; Matte, Thomas D; Johnson, Sarah; Dominici, Francesca; Clougherty, Jane E

    2015-10-01

    Numerous studies have linked air pollution with adverse birth outcomes, but relatively few have examined differential associations across the socioeconomic gradient. To evaluate interaction effects of gestational nitrogen dioxide (NO2) and area-level socioeconomic deprivation on fetal growth, we used: (1) highly spatially-resolved air pollution data from the New York City Community Air Survey (NYCCAS); and (2) spatially-stratified principle component analysis of census variables previously associated with birth outcomes to define area-level deprivation. New York City (NYC) hospital birth records for years 2008-2010 were restricted to full-term, singleton births to non-smoking mothers (n=243,853). We used generalized additive mixed models to examine the potentially non-linear interaction of nitrogen dioxide (NO2) and deprivation categories on birth weight (and estimated linear associations, for comparison), adjusting for individual-level socio-demographic characteristics and sensitivity testing adjustment for co-pollutant exposures. Estimated NO2 exposures were highest, and most varying, among mothers residing in the most-affluent census tracts, and lowest among mothers residing in mid-range deprivation tracts. In non-linear models, we found an inverse association between NO2 and birth weight in the least-deprived and most-deprived areas (p-values<0.001 and 0.05, respectively) but no association in the mid-range of deprivation (p=0.8). Likewise, in linear models, a 10 ppb increase in NO2 was associated with a decrease in birth weight among mothers in the least-deprived and most-deprived areas of -16.2g (95% CI: -21.9 to -10.5) and -11.0 g (95% CI: -22.8 to 0.9), respectively, and a non-significant change in the mid-range areas [β=0.5 g (95% CI: -7.7 to 8.7)]. Linear slopes in the most- and least-deprived quartiles differed from the mid-range (reference group) (p-values<0.001 and 0.09, respectively). The complex patterning in air pollution exposure and deprivation

  1. High-fat diet aggravates glucose homeostasis disorder caused by chronic exposure to bisphenol A.

    PubMed

    Ding, Shibin; Fan, Ying; Zhao, Nana; Yang, Huiqin; Ye, Xiaolei; He, Dongliang; Jin, Xin; Liu, Jian; Tian, Chong; Li, Hongyu; Xu, Shunqing; Ying, Chenjiang

    2014-04-01

    Epidemiological findings on the association between bisphenol A (BPA, 2,2-bis-(4-hydroxyphenyl)propane) exposure and type 2 diabetes mellitus (T2DM) are paradoxical. In animal studies, BPA has been shown to disrupt pancreatic function and blood glucose homeostasis even at a reference 'safe' level during perinatal period. In this study, we explored the effects of long-term paternal exposure to a 'safe' level of BPA on parents themselves and their offspring. Adult male genitor rats fed with either standard chow diet (STD) or high-fat diet (HFD) were treated respectively with either vehicle or BPA (50 μg/kg per day) for 35 weeks. The male rats treated with vehicle or BPA for 21 weeks were then used as sires, and the adult female rats were fed with STD during the gestation and lactation. Offspring rats were weaned on postnatal day 21 and fed with STD in later life. Metabolic parameters were recorded on the adult male rats and their adult offspring. BPA exposure disrupted glucose homeostasis and pancreatic function, and HFD aggravated these adverse effects. However, BPA exposure did not alter body weight, body fat percentage, or serum lipid. In addition, the paternal BPA exposure did not cause adverse reproductive consequence or metabolic disorder in the adult offspring. Our findings indicate that chronic exposure to a predicted 'safe' dose of BPA contributes to glucose metabolic disorders, and that HFD aggravates these adverse effects in paternal rats.

  2. Increased corticosterone levels in mice subjected to the rat exposure test.

    PubMed

    Amaral, Vanessa Cristiane Santana; Santos Gomes, Karina; Nunes-de-Souza, Ricardo Luiz

    2010-02-01

    In recent years, there has been a notable interest in studying prey-predator relationships to develop rodent-based models for the neurobehavioral aspects of stress and emotion. However, despite the growing use of transgenic mice and results showing important differences in the behavioral responses of rats and mice, little research has been conducted regarding the responses of mice to predators. The rat exposure test (RET), a recently developed and behaviorally validated prey-predator (mouse-rat)-based model, has proven to be a useful tool in evaluating the defensive responses of mice facing rats. To further validate the RET, we investigated the endocrine and behavioral responses of mice exposed to this apparatus. We first constructed a plasma corticosterone secretion curve in mice exposed to a rat or to an empty cage (control). Rat-exposed mice showed a pronounced rise in corticosterone levels that peaked 15 min from the beginning of the predator exposure. The corticosterone levels and behavioral responses of mice exposed to a rat or to a toy in the RET apparatus were then measured. We observed high plasma corticosterone levels along with clear avoidance behaviors represented by decreases in tunnel and surface area exploration and increases in risk assessment behaviors and freezing. This strongly suggests that the test elicits a repertoire of behavioral responses compatible with an aversion state and indicates that it is a promising model for the evaluation of prey-predator interactions. However, more physiological, neurochemical, and pharmacological studies are needed to further validate the test. Copyright 2009 Elsevier Inc. All rights reserved.

  3. Incidence of amikacin ototoxicity: a sigmoid function of total drug exposure independent of plasma levels.

    PubMed

    Beaubien, A R; Desjardins, S; Ormsby, E; Bayne, A; Carrier, K; Cauchy, M J; Henri, R; Hodgen, M; Salley, J; St Pierre, A

    1989-01-01

    A sigmoid curve was found to closely describe the relationship between the incidence of amikacin ototoxicity (greater than or equal to 15 dB hearing loss at a given frequency) and either (1) total dose, or (2) the area under the curve (AUC) describing plasma drug concentration v time over the total period of amikacin administration (total AUC) in continuously infused guinea pigs. Total dose or total AUC estimates of the drug exposure required to produce ototoxicity in 50% of the animals (ED50s) were not significantly different over an eight-fold range of dosing rates or plasma concentrations. A theoretical explanation for this result is that ototoxicity occurs only when a critical amount of drug is accumulated at the ototoxic site by an essentially unidirectional process with a rate that is slow and linearly related to the extracellular drug concentration. The sigmoid relationships for pooled data were parallel in slope for all hearing frequencies from 2 to 32 kHz, and the ED50s showed a strong negative linear relationship to the log of the hearing frequency over this range. The magnitude of ototoxicity expressed as the number of octaves (frequency ratios of 2) for which hearing loss damage was continuous from 32 kHz downward, was correlated to both total dose (r = .605) and total AUC (r = 0.703). No relationship between ototoxicity and plasma level or dosing rate was found. The extreme steepness of the dose-effect curve for the incidence of ototoxicity greatly amplified the variability between individuals and offers an explanation for the unpredictability of aminoglycoside ototoxicity in human patients. The results indicate that either total dose or total AUC (in cases of highly unpredictable blood levels), and not peak or trough serum levels, should be used as an index of ototoxic risk and that the safety limits of drug exposure should be set conservatively.

  4. Development of a multimedia radionuclide exposure model for low-level waste management

    SciTech Connect

    Onishi, Y.; Whelan, G.; Skaggs, R.L.

    1982-03-01

    A method is being developed for assessing exposures of the air, water, and plants to low-level waste (LLW) as a part of an overall development effort of a LLW site evaluation methodology. The assessment methodology will predict LLW exposure levels in the environment by simulating dominant mechanisms of LLW migration and fate. The methodology consists of a series of physics-based models with proven histories of success; the models interact with each other to simulate LLW transport in the ecosystem. A scaled-down version of the methodology was developed first by combining the terrestrial ecological model, BIOTRAN; the overland transport model, ARM; the instream hydrodynamic model, DKWAV; and the instream sediment-contaminant transport model, TODAM (a one-dimensional version of SERATRA). The methodology was used to simulate the migration of /sup 239/Pu from a shallow-land disposal site (known as Area C) located near the head of South Mortandad Canyon on the LANL site in New Mexico. The scenario assumed that /sup 239/Pu would be deposited on the land surface through the natural processes of plant growth, LLW uptake, dryfall, and litter decomposition. Runoff events would then transport /sup 239/Pu to and in the canyon. The model provided sets of simulated LLW levels in soil, water and terrestrial plants in the region surrounding the site under a specified land-use and a waste management option. Over a 100-yr simulation period, only an extremely small quantity (6 x 10/sup -9/ times the original concentration) of buried /sup 239/Pu was taken up by plants and deposited on the land surface. Only a small fraction (approximately 1%) of that contamination was further removed by soil erosion from the site and carried to the canyon, where it remained. Hence, the study reveals that the environment around Area C has integrity high enough to curtail LLW migration under recreational land use.

  5. Low-level inorganic arsenic exposure and neuropsychological functioning in American Indian elders.

    PubMed

    Carroll, Clint R; Noonan, Carolyn; Garroutte, Eva M; Navas-Acien, Ana; Verney, Steven P; Buchwald, Dedra

    2017-07-01

    Inorganic arsenic at high and prolonged doses is highly neurotoxic. Few studies have evaluated whether long-term, low-level arsenic exposure is associated with neuropsychological functioning in adults. To investigate the association between long-term, low-level inorganic arsenic exposure and neuropsychological functioning among American Indians aged 64-95. We assessed 928 participants in the Strong Heart Study by using data on arsenic species in urine samples collected at baseline (1989-1991) and results of standardized tests of global cognition, executive functioning, verbal learning and memory, fine motor functioning, and speed of mental processing administered during comprehensive follow-up evaluations in 2009-2013. We calculated the difference in neuropsychological functioning for a 10% increase in urinary arsenic with adjustment for sex, age, education, and study site. The sum of inorganic and methylated arsenic species (∑As) in urine was associated with limited fine motor functioning and processing speed. A 10% increase in ∑As was associated with a .10 (95% CI -.20, -.01) decrease on the Finger Tapping Test for the dominant hand and a .13 decrease (95% CI -.21, -.04) for the non-dominant hand. Similarly, a 10% increase in ∑As was associated with a .15 (95% CI -.29, .00) decrease on the Wechsler Adult Intelligence Scale-Fourth Edition Coding Subtest. ∑As was not associated with other neuropsychological functions. Findings indicate an adverse association between increased urinary arsenic fine motor functioning and processing speed, but not with other neuropsychological functioning, among elderly American Indians. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Catecholamine response during 12 days of high-altitude exposure (4, 300 m) in women.

    PubMed

    Mazzeo, R S; Child, A; Butterfield, G E; Mawson, J T; Zamudio, S; Moore, L G

    1998-04-01

    We have previously demonstrated that acclimatization to high altitude elicits increased sympathetic nerve activity in men. The purpose of this investigation was to determine 1) whether women respond in a similar manner as found previously in men and 2) the extent to which menstrual cycle phase influences this response. Sixteen eumenorrheic women (age, 23.6 +/- 1.2 yr; weight, 56.2 +/- 4. 3 kg) were studied at sea level and during 12 days of high-altitude exposure (4,300 m) in either their follicular (F; n = 11) or luteal (L; n = 5) phase. Twenty-four-hour urine samples were collected at sea level and during each day at altitude. Catecholamines were determined by high-performance liquid chromatography with electrochemical detection. Compared with sea-level values, urinary norepinephrine excretion increased significantly during altitude exposure, peaking on days 4-6. Thereafter, levels remained constant throughout the duration of altitude exposure. The magnitude of this increase was similar between the F (138%) and L (93%) phase. Urinary epinephrine levels were elevated on day 2 of altitude exposure compared with sea-level values for both F and L subjects (93%). Thereafter, urinary epinephrine excretion returned to sea-level values, and no differences were found between F and L subjects. Plasma catecholamine content was consistent with urinary values and supports the concept of an elevation in sympathetic activity over time at altitude. Mean and diastolic blood pressure as well as heart rate adjustments to high altitude correlated significantly with urinary norepinephrine excretion rates. It was concluded that 1) urinary and plasma catecholamine responses to 12 days of high-altitude exposure in women are similar to those previously documented to occur for men; 2) whereas no differences in catecholamine levels were observed between F- and L-phase assignments, for a given urinary norepinephrine excretion rate, blood pressure and heart rates were lower for F vs. L

  7. High Throughput Modeling of Indoor Exposures to Chemicals (SOT)

    EPA Science Inventory

    Risk due to chemical exposure is a function of both chemical hazard and exposure. Proximate sources of exposure due to the presence of a chemical in consumer products (i.e. near-field exposure) are identified as key drivers of exposure and yet are not well quantified or understo...

  8. High Throughput Modeling of Indoor Exposures to Chemicals (SOT)

    EPA Science Inventory

    Risk due to chemical exposure is a function of both chemical hazard and exposure. Proximate sources of exposure due to the presence of a chemical in consumer products (i.e. near-field exposure) are identified as key drivers of exposure and yet are not well quantified or understo...

  9. Exposure to electromagnetic fields aboard high-speed electric multiple unit trains.

    PubMed

    Niu, D; Zhu, F; Qiu, R; Niu, Q

    2016-01-01

    High-speed electric multiple unit (EMU) trains generate high-frequency electric fields, low-frequency magnetic fields, and high-frequency wideband electromagnetic emissions when running. Potential human health concerns arise because the electromagnetic disturbances are transmitted mainly into the car body from windows, and from there to passengers and train staff. The transmission amount and amplitude distribution characteristics that dominate electromagnetic field emission need to be studied, and the exposure level of electromagnetic field emission to humans should be measured. We conducted a series of tests of the on board electromagnetic field distribution on several high-speed railway lines. While results showed that exposure was within permitted levels, the possibility of long-term health effects should be investigated.

  10. Smoking as a determinant of high organochlorine levels in Greenland.

    PubMed

    Deutch, Bente; Pedersen, Henning Sloth; Jørgensen, Eva C Bonefeld; Hansen, Jens C

    2003-01-01

    The authors investigated the accumulation of organochlorines among smoking and nonsmoking Inuit hunters (n = 48) in Uummanaq, Greenland, a population with high dietary exposure to persistent organic pollutants (POPs). Human plasma organochlorine levels were positively correlated with age, marine diet, and smoking or plasma cotinine in multiple linear-regression models (p < 0.001). Body mass index was inversely correlated with organochlorine accumulation, independent of smoking status. These findings confirm that the source of POPs among the Inuit in Greenland is diet, but smoking is an important determinant of POP bioaccumulation. Smoking cessation may provide a means to lower the body burden of POPs.

  11. Modeling human exposure levels to airborne volatile organic compounds by the hebei spirit oil spill.

    PubMed

    Kim, Jong Ho; Kwak, Byoung Kyu; Ha, Mina; Cheong, Hae-Kwan; Yi, Jongheop

    2012-01-01

    The goal was to model and quantify the atmospheric concentrations of volatile organic compounds (VOCs) as the result of the Hebei Spirit oil spill, and to predict whether the exposure levels were abnormally high or not. We developed a model for calculating the airborne concentration of VOCs that are produced in an oil spill accident. The model was applied to a practical situation, namely the Hebei Spirit oil spill. The accuracy of the model was verified by comparing the results with previous observation data. The concentrations were compared with the currently used air quality standards. Evaporation was found to be 10- to 1,000-fold higher than the emissions produced from a surrounding industrial complex. The modeled concentrations for benzene failed to meet current labor environmental standards, and the concentration of benzene, toluene, ortho- meta- para-xylene were higher than the values specified by air quality standards and guideline values on the ocean. The concentrations of total VOCs were much higher than indoor environmental criteria for the entire Taean area for a few days. The extent of airborne exposure was clearly not the same as that for normal conditions.

  12. Modeling Human Exposure Levels to Airborne Volatile Organic Compounds by the Hebei Spirit Oil Spill

    PubMed Central

    Kim, Jong Ho; Kwak, Byoung Kyu; Ha, Mina; Cheong, Hae-Kwan

    2012-01-01

    Objectives The goal was to model and quantify the atmospheric concentrations of volatile organic compounds (VOCs) as the result of the Hebei Spirit oil spill, and to predict whether the exposure levels were abnormally high or not. Methods We developed a model for calculating the airborne concentration of VOCs that are produced in an oil spill accident. The model was applied to a practical situation, namely the Hebei Spirit oil spill. The accuracy of the model was verified by comparing the results with previous observation data. The concentrations were compared with the currently used air quality standards. Results Evaporation was found to be 10- to 1,000-fold higher than the emissions produced from a surrounding industrial complex. The modeled concentrations for benzene failed to meet current labor environmental standards, and the concentration of benzene, toluene, ortho- meta- para-xylene were higher than the values specified by air quality standards and guideline values on the ocean. The concentrations of total VOCs were much higher than indoor environmental criteria for the entire Taean area for a few days. Conclusions The extent of airborne exposure was clearly not the same as that for normal conditions. PMID:22468262

  13. Levels and determinants of exposure to vapours and aerosols of bitumen.

    PubMed

    Spickenheuer, Anne; Rühl, Reinhold; Höber, Dieter; Raulf-Heimsoth, Monika; Marczynski, Boleslaw; Welge, Peter; Breuer, Dietmar; Gabriel, Stefan; Musanke, Uwe; Rode, Peter; Heinze, Evelyn; Kendzia, Benjamin; Bramer, Rainer; Knecht, Udo; Hahn, Jens-Uwe; Brüning, Thomas; Pesch, Beate

    2011-06-01

    Bitumen (referred to as asphalt in the United States) is a widely used construction material, and emissions from hot bitumen applications have been a long-standing health concern. One objective of the Human Bitumen Study was to identify potential determinants of the exposure to bitumen. The study population analysed comprised 259 male mastic asphalt workers recruited between 2003 and 2008. Personal air sampling in the workers' breathing zone was carried out during the shift to measure exposure to vapours and aerosols of bitumen. The majority of workers were engaged in building construction, where exposure levels were lower than in tunnels but higher than at road construction sites. At building construction sites, exposure levels were influenced by the room size, the processing temperature of the mastic asphalt and the job task. The results show that protective measures should include a reduction in the processing temperature.

  14. Behavioral evaluation of rats following low-level inhalation exposure to sarin.

    PubMed

    Genovese, Raymond F; Mioduszewski, Robert J; Benton, Bernard J; Pare, Matthew A; Cooksey, Jessica A

    2009-02-01

    We evaluated the effects, in rats, of single and multiple low-level inhalation exposures to sarin. Rats were trained on a variable-interval, 56 s (VI56) schedule of food reinforcement and then exposed to sarin vapor (1.7-4.0 mg/m(3) x 60 min) or air control. The exposures did not produce clinical signs of toxicity other than miosis. Subsequently, performance on the VI56 and acquisition of a radial-arm maze spatial memory task was evaluated over approximately 11 weeks. Single exposures did not affect performance on the VI56 and had little effect on acquisition of the radial-arm maze task. Multiple exposures (4.0 mg/m(3) x 60 min/day x 3) disrupted performance on the VI56 schedule during the initial post-exposure sessions. The disruption, however, resolved after several days. Multiple exposures also produced a deficit on the radial-arm maze task in that sarin-exposed rats tended to take it longer to complete the maze and to make more errors. The deficit, however, resolved during the first three weeks of acquisition. These results demonstrate that in rats, inhalation exposure to sarin at levels below those causing overt signs of clinical toxicity can produce cognitive and performance deficits. Furthermore, the observed deficits do not appear to be persistent.

  15. Effect of Short-term 900 MHz low level electromagnetic radiation exposure on blood serotonin and glutamate levels.

    PubMed

    Eris, A H; Kiziltan, H S; Meral, I; Genc, H; Trabzon, M; Seyithanoglu, H; Yagci, B; Uysal, O

    2015-01-01

    Long term exposure to low level electromagnetic radiation (LLER) by using cellular phones causes serious health problems. Ten male Wistar Albino rats were anesthetized 30 min before the LLER exposure, 0.5 ml blood was taken from the tail vein of rats in order to determine control values. Rats were grouped by three and placed on a plexi-glass flat. A fixed equivalent frequency emitter device was used. A sign to be an electromagnetic field 15.14 V/m (608 mW/m(2)) in strength in the head region with 100 kHz FM modulation at 900 MHz was applied to the animals. After calculating the ideal position for the device, electromagnetic LLER energy was applied for 45 minutes from a distance to be equal with energy transmitted by a mobile phone from a 0.5-1 cm distance to their head regions. After 1.5 hours and before the rats awoke, 0.5 ml of blood was taken from the tail veins in order to determine the treatment values. Plasma 5-HT and glutamate levels were measured by enzyme immunoassay (EIA) using commercial kits. It was found that a single 45 min of LLER exposure increased the blood 5-HT level significantly, but did not change the glutamate level of rats. It was concluded that even a single 45 min of LLER exposure may produce an increase in 5-HT level without changing the blood glutamate level. Increased 5-HT level may lead to a retarded learning and a deficit in spatial memory (Tab. 2, Fig. 2, Ref. 24).

  16. The inverse dose-rate effect and the extrapolation of radon risk estimates from exposures of miners to low-level exposures in homes

    SciTech Connect

    Pushkin, J.S. )

    1994-04-01

    This letter is written in response to a paper in which the author discusses the inverse dose-rate dependence of oncogenic transformation by high-LET radiation. The author asserts that, as a consequence, the extrapolation of results from miners exposed to high levels of radon daughters could overestimate the risk due to environmental exposures. By using a model increased cell sensitivity in one part of the cell cycle, the author assumes an inverse dose-rate effect should occur only at high doses, but the author of this letter points out that this does not imply a lower risk per unit dose at low doses. According to this letter, the existence of an inverse dose-rate effect for high-LET radiation provides no grounds for projecting lower lung cancer risks per unit exposure at environmental radon levels than at the higher radon level in mines. Failure to adjust for any inverse dose-rate effect in the studies of miners can only lead to an underestimation of the environmental risk.