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Sample records for exposure rate synthesis

  1. Expression of cytoskeletal and matrix genes following exposure to ionizing radiation: Dose-rate effects and protein synthesis requirements

    SciTech Connect

    Woloschak, G.E. |; Felcher, P.; Chin-Mei Chang-Liu

    1995-06-01

    Experiments examined the effects of radiation dose-rate and protein synthesis inhibition expression of cytoskeletal and matrix elements in Syrian hamster embryo cells. Results demonstrated little effect of dose-rate for neutrons when comparing expression of {alpha}-tubulin and fibronectin genes. Cycloheximide repressed accumulation of {alpha}-tubulin-mRNA following exposure to high dose-rate neutrons or {gamma} rays. Cycloheximide did not affect accumulation of actin mRNA. Cycloheximide abrogated induction of fibronectin-mRNA which occurred following exposure to {gamma} rays and high dose-rate neutrons. These results suggest a role for labile proteins in the maintenance of {alpha}-tubulin and fibronectin mRNA accumulation following exposure to radiation. 24 refs., 3 tabs.

  2. Expression of cytoskeletal and matrix genes following exposure to ionizing radiation: Dose-rate effects and protein synthesis requirements

    SciTech Connect

    Woloschak, G.E. |; Felcher, P.; Chang-Liu, Chin-Mei

    1993-12-31

    Experiments were designed to examine the effects of radiation dose-rate and of the protein synthesis inhibitor cycloheximide on expression of cytoskeletal elements ({gamma}- and {beta}-actin and {alpha}-tubulin) and matrix elements (fibronectin) in Syrian hamster embryo cells. Results demonstrated little effect of dose-rate for JANUS fission-spectrum neutrons when comparing expression of either a-tubulin or fibronectin genes. Past work had already documented similar results for expression of actin transcripts. Cycloheximide, however, repressed accumulation of {alpha}-tubulin following exposure to high dose-rate neutrons or {gamma} rays; this did not occur following similar low dose-rate exposures. Cycloheximide did not affect accumulation of mRNA for actin genes. Cycloheximide abrogated the moderate induction of fibronectin-mRNA which occurred following exposure to {gamma} rays and high dose-rate neutrons. These results suggest a role for labile proteins in the maintenance of {alpha}-tubulin and fibronectin mRNA accumulation following exposure to ionizing radiation and that the cellular/molecular response to low dose-rate neutrons may be different from the response to high dose-rate neutrons.

  3. Expression of cytoskeletal and matrix genes following exposure to ionizing radiation: Dose-rate effects and protein synthesis requirements

    SciTech Connect

    Woloschak, G.E. |; Felcher, P.; Chang-Liu, Chin-Mei

    1992-12-31

    Experiments were designed to examine the effects of radiation dose-rate and of the protein synthesis inhibitor cycloheximide on expression of cytoskeletal elements ({gamma}- and {beta}-actin and {alpha}-tubulin) and matrix elements (fibronectin) in Syrian hamster embryo cells. Past work from our laboratory had already demonstrated optimum time points and doses for examination of radiation effects on accumulation of specific transcripts. Our results here demonstrated little effect of dose-rate for JANUS fission spectrum neutrons when comparing expression of either {alpha}-tubulin or fibronectin genes. Past work had already documented similar results for expression of actin transcripts. Effects of cycloheximide, however, revealed several interesting and novel findings: (1) Cycloheximide repressed accumulation of {alpha}-tubulin following exposure to high dose-rate neutrons or {gamma} rays; this did not occur following similar low dose-rate exposure (2) Cycloheximide did not affect accumulation of mRNA for actin genes. Cycloheximide abrogated the moderate induction of fibronectin-mRNA which occurred following exposure to {gamma} rays and high dose-rate neutrons. These results suggest a role for labile proteins in the maintenance of {alpha}-tubulin and fibronectin mRNA accumulation following exposure to ionizing radiation. In addition, they suggest that the cellular/molecular response to low dose-rate neutrons may be different from the response to high dose-rate neutrons.

  4. Expression of cytoskeletal and matrix genes following exposure to ionizing radiation: Dose-rate effects and protein synthesis requirements

    SciTech Connect

    Woloschak, G.E. |; Felcher, P.; Chang-Liu, Chin-Mei

    1994-05-01

    Experiments were designed to examine the effects Of radiation dose-rate and of the protein synthesis inhibitor cycloheximide on expression of cytoskeletal elements ({gamma}- and {beta}-actin and {alpha}-tubulin) and matrix elements (fibronectin) in Syrian hamster embryo cells. Past work from our laboratory had already demonstrated optimum time points and doses for examination of radiation effects on accumulation of specific transcripts. Our results here demonstrated little effect of dose-rate for JANUS fission spectrum neutrons when comparing expression of either {alpha}-tubulin or fibronectin genes. Past work had already documented similar results for expression of actin transcripts. Effects of cycloheximide revealed that cycloheximide repressed accumulation of {alpha}-tubulin following exposure to high dose-rate neutrons or {gamma} rays; this did not occur following similar low dose-rate exposure. (2) Cycloheximide did not affect accumulation of MRNA for actin genes; and that cycloheximide abrogated the moderate induction of fibronectin-mRNA which occurred following exposure to {gamma} rays and high dose-rate neutrons. These results suggest a role for labile proteins in the maintenance of {alpha}-tubulin and fibronectin MRNA accumulation following exposure to ionizing radiation. in addition, they suggest that the cellular/molecular response to low dose-rate neutrons may be different from the response to high dose-rate neutrons.

  5. Prenatal Exposure of Cypermethrin Induces Similar Alterations in Xenobiotic-Metabolizing Cytochrome P450s and Rate-Limiting Enzymes of Neurotransmitter Synthesis in Brain Regions of Rat Offsprings During Postnatal Development.

    PubMed

    Singh, Anshuman; Mudawal, Anubha; Maurya, Pratibha; Jain, Rajeev; Nair, Saumya; Shukla, Rajendra K; Yadav, Sanjay; Singh, Dhirendra; Khanna, Vinay Kumar; Chaturvedi, Rajnish Kumar; Mudiam, Mohana K R; Sethumadhavan, Rao; Siddiqi, Mohammad Imran; Parmar, Devendra

    2016-08-01

    Oral administration of low doses of cypermethrin to pregnant Wistar rats led to a dose-dependent differences in the induction of xenobiotic-metabolizing cytochrome P450s (CYPs) messenger RNA (mRNA) and protein in brain regions isolated from the offsprings postnatally at 3 weeks that persisted up to adulthood. Similar alterations were observed in the expression of rate-limiting enzymes of neurotransmitter synthesis in brain regions of rat offsprings. These persistent changes were associated with alterations in circulating levels of growth hormone (GH), cognitive functions, and accumulation of cypermethrin and its metabolites in brain regions of exposed offsprings. Though molecular docking studies failed to identify similarities between the docked conformations of cypermethrin with CYPs and neurotransmitter receptors, in silico analysis identified regulatory sequences of CYPs in the promoter region of rate-limiting enzymes of neurotransmitter synthesis. Further, rechallenge of the prenatally exposed offsprings at adulthood with cypermethrin (p.o. 10 mg/kg × 6 days) led to a greater magnitude of alterations in the expression of CYPs and rate-limiting enzymes of neurotransmitter synthesis in different brain regions. These alterations were associated with a greater magnitude of decrease in the circulating levels of GH and cognitive functions in rechallenged offsprings. Our data has led us to suggest that due to the immaturity of CYPs in fetus or during early development, even the low-level exposure of cypermethrin may be sufficient to interact with the CYPs, which in turn affect the neurotransmission processes and may help in explaining the developmental neurotoxicity of cypermethrin.

  6. Increased synthesis of folate transporters regulates folate transport in conditions of ethanol exposure and folate deficiency.

    PubMed

    Thakur, Shilpa; More, Deepti; Rahat, Beenish; Khanduja, Krishan Lal; Kaur, Jyotdeep

    2016-01-01

    Excessive alcohol consumption and dietary folate inadequacy are the main contributors leading to folate deficiency (FD). The present study was planned to study regulation of folate transport in conditions of FD and ethanol exposure in human embryonic kidney cell line. Also, the reversible nature of effects mediated by ethanol exposure and FD was determined by folate repletion and ethanol removal. For ethanol treatment, HEK293 cells were grown in medium containing 100 mM ethanol, and after treatment, one group of cells was shifted on medium that was free from ethanol. For FD treatment, cells were grown in folate-deficient medium followed by shifting of one group of cells on folate containing medium. FD as well as ethanol exposure resulted in an increase in folate uptake which was due to an increase in expression of folate transporters, i.e., reduced folate carrier, proton-coupled folate transporter, and folate receptor, both at the mRNA and protein level. The effects mediated by ethanol exposure and FD were reversible on removal of treatment. Promoter region methylation of folate transporters remained unaffected after FD and ethanol exposure. As far as transcription rate of folate transporters is concerned, an increase in rate of synthesis was observed in both ethanol exposure and FD conditions. Additionally, mRNA life of folate transporters was observed to be reduced by FD. An increased expression of folate transporters under ethanol exposure and FD conditions can be attributed to enhanced rate of synthesis of folate transporters.

  7. Environmental chemical exposures and disturbances of heme synthesis.

    PubMed Central

    Daniell, W E; Stockbridge, H L; Labbe, R F; Woods, J S; Anderson, K E; Bissell, D M; Bloomer, J R; Ellefson, R D; Moore, M R; Pierach, C A; Schreiber, W E; Tefferi, A; Franklin, G M

    1997-01-01

    Porphyrias are relatively uncommon inherited or acquired disorders in which clinical manifestations are attributable to a disturbance of heme synthesis (porphyrin metabolism), usually in association with endogenous or exogenous stressors. Porphyrias are characterized by elevations of heme precursors in blood, urine, and/or stool. A number of chemicals, particularly metals and halogenated hydrocarbons, induce disturbances of heme synthesis in experimental animals. Certain chemicals have also been linked to porphyria or porphyrinuria in humans, generally involving chronic industrial exposures or environmental exposures much higher than those usually encountered. A noteworthy example is the Turkish epidemic of porphyria cutanea tarda produced by accidental ingestion of wheat treated with the fungicide hexachlorobenzene. Measurements of excreted heme precursors have the potential to serve as biological markers for harmful but preclinical effects of certain chemical exposures; this potential warrants further research and applied field studies. It has been hypothesized that several otherwise unexplained chemical-associated illnesses, such as multiple chemical sensitivity syndrome, may represent mild chronic cases of porphyria or other acquired abnormalities in heme synthesis. This review concludes that, although it is reasonable to consider such hypotheses, there is currently no convincing evidence that these illnesses are mediated by a disturbance of heme synthesis; it is premature or unfounded to base clinical management on such explanations unless laboratory data are diagnostic for porphyria. This review discusses the limitations of laboratory measures of heme synthesis, and diagnostic guidelines are provided to assist in evaluating the symptomatic individual suspected of having a porphyria. PMID:9114276

  8. Effective biological dose from occupational exposure during nanoparticle synthesis

    NASA Astrophysics Data System (ADS)

    Demou, Evangelia; Tran, Lang; Housiadas, Christos

    2009-02-01

    Nanomaterial and nanotechnology safety require the characterization of occupational exposure levels for completing a risk assessment. However, equally important is the estimation of the effective internal dose via lung deposition, transport and clearance mechanisms. An integrated source-to-biological dose assessment study is presented using real monitoring data collected during nanoparticle synthesis. Experimental monitoring data of airborne exposure levels during nanoparticle synthesis of CaSO4 and BiPO4 nanoparticles in a research laboratory is coupled with a human lung transport and deposition model, which solves in an Eulerian framework the general dynamic equation for polydisperse aerosols using particle specific physical-chemical properties. Subsequently, the lung deposition model is coupled with a mathematical particle clearance model providing the effective biological dose as well as the time course of the biological dose build-up after exposure. The results for the example of BiPO4 demonstrate that even short exposures throughout the day can lead to particle doses of 1.10·E+08#/(kg-bw·8h-shift), with the majority accumulating in the pulmonary region. Clearance of particles is slow and is not completed within a working shift following a 1 hour exposure. It mostly occurs via macrophage activity in the alveolar region, with small amounts transported to the interstitium and less to the lymph nodes.

  9. Mercury Exposure and Heart Rate Variability: A Systematic Review

    PubMed Central

    Gribble, Matthew O.; Cheng, Alan; Berger, Ronald D.; Rosman, Lori; Guallar, Eliseo

    2015-01-01

    Background Mercury affects the nervous system and has been implicated in altering heart rhythm and function. We sought to better define its role in modulating heart rate variability, a well-known marker of cardiac autonomic function. Design Systematic review. Methods We searched PubMed, Embase, TOXLINE and DART databases without language restriction. We report findings as a qualitative systematic review because heterogeneity in study design and assessment of exposures and outcomes across studies, as well as other methodological limitations of the literature, precluded a quantitative meta-analysis. Results We identified 12 studies of mercury exposure and heart rate variability in human populations (10 studies involving primarily environmental methylmercury exposure and two studies involving occupational exposure to inorganic mercury) conducted in Japan, the Faroe Islands, Canada, Korea, French Polynesia, Finland and Egypt. The association of prenatal mercury exposure with lower high-frequency band scores (thought to reflect parasympathetic activity) in several studies, in particular the inverse association of cord blood mercury levels with the coefficient of variation of the R-R intervals and with low frequency and high frequency bands at 14 years of age in the Faroe Islands birth cohort study, suggests that early mercury exposure could have a long-lasting effect on cardiac parasympathetic activity. Studies with later environmental exposures to mercury in children or in adults were heterogeneous and did not show consistent associations. Conclusions The evidence was too limited to draw firm causal inferences. Additional research is needed to elucidate the effects of mercury on cardiac autonomic function, particularly as early-life exposures might have lasting impacts on cardiac parasympathetic function. PMID:26231507

  10. Circulating protein synthesis rates reveal skeletal muscle proteome dynamics

    PubMed Central

    Shankaran, Mahalakshmi; King, Chelsea L.; Angel, Thomas E.; Holmes, William E.; Li, Kelvin W.; Colangelo, Marc; Price, John C.; Turner, Scott M.; Bell, Christopher; Hamilton, Karyn L.; Miller, Benjamin F.; Hellerstein, Marc K.

    2015-01-01

    Here, we have described and validated a strategy for monitoring skeletal muscle protein synthesis rates in rodents and humans over days or weeks from blood samples. We based this approach on label incorporation into proteins that are synthesized specifically in skeletal muscle and escape into the circulation. Heavy water labeling combined with sensitive tandem mass spectrometric analysis allowed integrated synthesis rates of proteins in muscle tissue across the proteome to be measured over several weeks. Fractional synthesis rate (FSR) of plasma creatine kinase M-type (CK-M) and carbonic anhydrase 3 (CA-3) in the blood, more than 90% of which is derived from skeletal muscle, correlated closely with FSR of CK-M, CA-3, and other proteins of various ontologies in skeletal muscle tissue in both rodents and humans. Protein synthesis rates across the muscle proteome generally changed in a coordinate manner in response to a sprint interval exercise training regimen in humans and to denervation or clenbuterol treatment in rodents. FSR of plasma CK-M and CA-3 revealed changes and interindividual differences in muscle tissue proteome dynamics. In human subjects, sprint interval training primarily stimulated synthesis of structural and glycolytic proteins. Together, our results indicate that this approach provides a virtual biopsy, sensitively revealing individualized changes in proteome-wide synthesis rates in skeletal muscle without a muscle biopsy. Accordingly, this approach has potential applications for the diagnosis, management, and treatment of muscle disorders. PMID:26657858

  11. High-deposition-rate ceramics synthesis

    SciTech Connect

    Allendorf, M.D.; Osterheld, T.H.; Outka, D.A.

    1995-05-01

    Parallel experimental and computational investigations are conducted in this project to develop validated numerical models of ceramic synthesis processes. Experiments are conducted in the High-Temperature Materials Synthesis Laboratory in Sandia`s Combustion Research Facility. A high-temperature flow reactor that can accommodate small preforms (1-3 cm diameter) generates conditions under which deposition can be observed, with flexibility to vary both deposition temperature (up to 1500 K) and pressure (as low as 10 torr). Both mass spectrometric and laser diagnostic probes are available to provide measurements of gas-phase compositions. Experiments using surface analytical techniques are also applied to characterize important processes occuring on the deposit surface. Computational tools developed through extensive research in the combustion field are employed to simulate the chemically reacting flows present in typical industrial reactors. These include the CHEMKIN and Surface-CHEMKIN suites of codes, which permit facile development of complex reaction mechanisms and vastly simplify the implementation of multi-component transport and thermodynamics. Quantum chemistry codes are also used to estimate thermodynamic and kinetic data for species and reactions for which this information is unavailable.

  12. Protein synthesis rates in atrophied gastrocnemius muscles after limb immobilization

    NASA Technical Reports Server (NTRS)

    Tucker, K. R.; Seider, M. J.; Booth, F. W.

    1981-01-01

    Noting that protein synthesis declines in the gastrocnemius 6 hr after immobilization, the study sought to detect an increase of protein synthesis when the limb was freed, and to examine the effects of exercise on the rate of increase. Rats were used as subjects, with their hind legs in plaster of Paris in plantar flexion to eliminate strain on the gastrocnemius. Periods of immobilization were varied and samples of blood from the muscle were taken to track protein synthesis rates for different groups in immobilization and exercise regimens (running and weightlifting). Synthesis rates declined 3.6% during time in the cast, then increased 6.3%/day after the casts were removed. Both running and weightlifting were found to increase the fractional rate of protein formation in the gastrocnemius muscle when compared with contralateral muscles that were not exercised and were used as controls, suggesting that the mechanism controlling protein synthesis in skeletal muscles is rapidly responsive to changes in muscular contractile activity.

  13. Reversible suppression of protein synthesis in concert with polysome disaggregation during anoxia exposure in Littorina littorea.

    PubMed

    Larade, Kevin; Storey, Kenneth B

    2002-03-01

    Many marine invertebrates can live without oxygen for long periods of time, a capacity that is facilitated by the ability to suppress metabolic rate in anoxia to a value that is typically less than 10% of the normal aerobic rate. The present study demonstrates that a reduction in the rate of protein synthesis is one factor in the overall anoxia-induced metabolic suppression in the marine snail, Littorina littorea. The rate of [3H]leucine incorporation into newly translated protein in hepatopancreas isolated from 48 h anoxic snails was determined to be 49% relative to normoxic controls. However, protein concentration in hepatopancreas did not change during anoxia, suggesting a coordinated suppression of net protein turnover. Analysis of hepatopancreas samples from snails exposed to 24-72 h anoxia showed a gradual disaggregation of polysomes into monosomes. A re-aggregation of monosomes into polysomes was observed after 3 h of aerobic recovery. Analysis of fractions from the ribosome profile using radiolabeled probe to detect alpha-tubulin transcripts confirmed a general decrease in protein translation during anoxia exposure (transcript association with polysomes decreased) with a reversal during aerobic recovery. Western blotting of hepatopancreas samples from normoxic, 24 h anoxic, and 1 h aerobic recovered snails demonstrated that eIF-2alpha is substantially phosphorylated during anoxia exposure and dephosphorylated during normoxia and aerobic recovery, suggesting a decrease in translation initiation during anoxia exposure. These results suggest that metabolic suppression during anoxia exposure in L. littorea involves a decrease in protein translation. PMID:12030368

  14. Saran-Chloropel plastic suit worker dose rates from airborne tritium exposure - first exposure hour

    SciTech Connect

    Edwards, T.

    1993-04-20

    Radiological Engineering was requested to develop Tritium Stay Time Chart dose rates for the 9 mil Saran-Chloropel (CPE) plastic suit for a period of one hour or less. Assumptions utilized in previous calculations were revised to better address the first hour of exposure in the suit for emergency situations.

  15. Effects of sound exposure on the growth and intracellular macromolecular synthesis of E. coli k-12

    PubMed Central

    Zhang, Yongzhu; Wu, Ying

    2016-01-01

    Microbes, as one of the primary producers of the biosphere, play an important role in ecosystems. Exploring the mechanism of adaptation and resistance of microbial population to various environmental factors has come into focus in the fields of modern microbial ecology and molecular ecology. However, facing the increasingly serious problem of acoustic pollution, very few efforts have been put forth into studying the relation of single cell organisms and sound field exposure. Herein, we studied the biological effects of sound exposure on the growth of E. coli K-12 with different acoustic parameters. The effects of sound exposure on the intracellular macromolecular synthesis and cellular morphology of E. coli K-12 were also analyzed and discussed. Experimental results indicated that E. coli K-12 exposed to sound waves owned a higher biomass and a faster specific growth rate compared to the control group. Also, the average length of E. coli K-12 cells increased more than 27.26%. The maximum biomass and maximum specific growth rate of the stimulation group by 8000 Hz, 80dB sound wave was about 1.7 times and 2.5 times that of the control group, respectively. Moreover, it was observed that E. coli K-12 can respond rapidly to sound stress at both the transcriptional and posttranscriptional levels by promoting the synthesis of intracellular RNA and total protein. Some potential mechanisms may be involved in the responses of bacterial cells to sound stress. PMID:27077011

  16. Effects of sound exposure on the growth and intracellular macromolecular synthesis of E. coli k-12.

    PubMed

    Gu, Shaobin; Zhang, Yongzhu; Wu, Ying

    2016-01-01

    Microbes, as one of the primary producers of the biosphere, play an important role in ecosystems. Exploring the mechanism of adaptation and resistance of microbial population to various environmental factors has come into focus in the fields of modern microbial ecology and molecular ecology. However, facing the increasingly serious problem of acoustic pollution, very few efforts have been put forth into studying the relation of single cell organisms and sound field exposure. Herein, we studied the biological effects of sound exposure on the growth of E. coli K-12 with different acoustic parameters. The effects of sound exposure on the intracellular macromolecular synthesis and cellular morphology of E. coli K-12 were also analyzed and discussed. Experimental results indicated that E. coli K-12 exposed to sound waves owned a higher biomass and a faster specific growth rate compared to the control group. Also, the average length of E. coli K-12 cells increased more than 27.26%. The maximum biomass and maximum specific growth rate of the stimulation group by 8000 Hz, 80dB sound wave was about 1.7 times and 2.5 times that of the control group, respectively. Moreover, it was observed that E. coli K-12 can respond rapidly to sound stress at both the transcriptional and posttranscriptional levels by promoting the synthesis of intracellular RNA and total protein. Some potential mechanisms may be involved in the responses of bacterial cells to sound stress.

  17. Effects of sound exposure on the growth and intracellular macromolecular synthesis of E. coli k-12.

    PubMed

    Gu, Shaobin; Zhang, Yongzhu; Wu, Ying

    2016-01-01

    Microbes, as one of the primary producers of the biosphere, play an important role in ecosystems. Exploring the mechanism of adaptation and resistance of microbial population to various environmental factors has come into focus in the fields of modern microbial ecology and molecular ecology. However, facing the increasingly serious problem of acoustic pollution, very few efforts have been put forth into studying the relation of single cell organisms and sound field exposure. Herein, we studied the biological effects of sound exposure on the growth of E. coli K-12 with different acoustic parameters. The effects of sound exposure on the intracellular macromolecular synthesis and cellular morphology of E. coli K-12 were also analyzed and discussed. Experimental results indicated that E. coli K-12 exposed to sound waves owned a higher biomass and a faster specific growth rate compared to the control group. Also, the average length of E. coli K-12 cells increased more than 27.26%. The maximum biomass and maximum specific growth rate of the stimulation group by 8000 Hz, 80dB sound wave was about 1.7 times and 2.5 times that of the control group, respectively. Moreover, it was observed that E. coli K-12 can respond rapidly to sound stress at both the transcriptional and posttranscriptional levels by promoting the synthesis of intracellular RNA and total protein. Some potential mechanisms may be involved in the responses of bacterial cells to sound stress. PMID:27077011

  18. The Exposure Rate Conversion Factor for Nuclear Fallout

    SciTech Connect

    Spriggs, G D

    2009-02-11

    Nuclear fallout is comprised of approximately 2000 radionuclides. About 1000 of these radionuclides are either primary fission products or activated fission products that are created during the burn process. The exposure rate one meter above the surface produced by this complex mixture of radionuclides varies rapidly with time since many of the radionuclides are short-lived and decay numerous times before reaching a stable isotope. As a result, the mixture of radionuclides changes rapidly with time. Using a new code developed at the Lawrence Livermore National Laboratory, the mixture of radionuclides at any given point in time can be calculated. The code also calculates the exposure rate conversion factor (ECF) for all 3864 individual isotopes contained in its database based on the total gamma energy released per decay. Based on the combination of isotope mixture and individual ECFs, the time-dependent variation of the composite exposure rate conversion factor for nuclear fallout can be easily calculated. As example of this new capability, a simple test case corresponding to a 10 kt, uranium-plutonium fuel has been calculated. The results for the time-dependent, composite ECF for this test case are shown in Figure 1. For comparison, we also calculated the composite exposure rate conversion factor using the conversion factors found in Federal Guidance Report No.12 (FGR-12) published by ORNL, which contains the conversion factors for approximately 1000 isotopes. As can be noted from Figure 1, the two functions agree reasonably well at times greater than about 30 minutes. However, they do not agree at early times since FGR-12 does not include all of the short-lived isotopes that are produced in nuclear fallout. It should also be noted that the composite ECF at one hour is 19.7 R/hr per Ci/m{sup 2}. This corresponds to 3148 R/hr per 1 kt per square mile, which agrees reasonably well with the value of 3000 R/hr per 1 kt per square mile as quoted by Glasstone. We have

  19. Cold adaptation increases rates of nutrient flow and metabolic plasticity during cold exposure in Drosophila melanogaster.

    PubMed

    Williams, Caroline M; McCue, Marshall D; Sunny, Nishanth E; Szejner-Sigal, Andre; Morgan, Theodore J; Allison, David B; Hahn, Daniel A

    2016-09-14

    Metabolic flexibility is an important component of adaptation to stressful environments, including thermal stress and latitudinal adaptation. A long history of population genetic studies suggest that selection on core metabolic enzymes may shape life histories by altering metabolic flux. However, the direct relationship between selection on thermal stress hardiness and metabolic flux has not previously been tested. We investigated flexibility of nutrient catabolism during cold stress in Drosophila melanogaster artificially selected for fast or slow recovery from chill coma (i.e. cold-hardy or -susceptible), specifically testing the hypothesis that stress adaptation increases metabolic turnover. Using (13)C-labelled glucose, we first showed that cold-hardy flies more rapidly incorporate ingested carbon into amino acids and newly synthesized glucose, permitting rapid synthesis of proline, a compound shown elsewhere to improve survival of cold stress. Second, using glucose and leucine tracers we showed that cold-hardy flies had higher oxidation rates than cold-susceptible flies before cold exposure, similar oxidation rates during cold exposure, and returned to higher oxidation rates during recovery. Additionally, cold-hardy flies transferred compounds among body pools more rapidly during cold exposure and recovery. Increased metabolic turnover may allow cold-adapted flies to better prepare for, resist and repair/tolerate cold damage. This work illustrates for the first time differences in nutrient fluxes associated with cold adaptation, suggesting that metabolic costs associated with cold hardiness could invoke resource-based trade-offs that shape life histories. PMID:27605506

  20. Cold adaptation increases rates of nutrient flow and metabolic plasticity during cold exposure in Drosophila melanogaster.

    PubMed

    Williams, Caroline M; McCue, Marshall D; Sunny, Nishanth E; Szejner-Sigal, Andre; Morgan, Theodore J; Allison, David B; Hahn, Daniel A

    2016-09-14

    Metabolic flexibility is an important component of adaptation to stressful environments, including thermal stress and latitudinal adaptation. A long history of population genetic studies suggest that selection on core metabolic enzymes may shape life histories by altering metabolic flux. However, the direct relationship between selection on thermal stress hardiness and metabolic flux has not previously been tested. We investigated flexibility of nutrient catabolism during cold stress in Drosophila melanogaster artificially selected for fast or slow recovery from chill coma (i.e. cold-hardy or -susceptible), specifically testing the hypothesis that stress adaptation increases metabolic turnover. Using (13)C-labelled glucose, we first showed that cold-hardy flies more rapidly incorporate ingested carbon into amino acids and newly synthesized glucose, permitting rapid synthesis of proline, a compound shown elsewhere to improve survival of cold stress. Second, using glucose and leucine tracers we showed that cold-hardy flies had higher oxidation rates than cold-susceptible flies before cold exposure, similar oxidation rates during cold exposure, and returned to higher oxidation rates during recovery. Additionally, cold-hardy flies transferred compounds among body pools more rapidly during cold exposure and recovery. Increased metabolic turnover may allow cold-adapted flies to better prepare for, resist and repair/tolerate cold damage. This work illustrates for the first time differences in nutrient fluxes associated with cold adaptation, suggesting that metabolic costs associated with cold hardiness could invoke resource-based trade-offs that shape life histories.

  1. Exposure Modeling of Residential Air Exchange Rates for NEXUS Participants

    EPA Science Inventory

    Due to cost and participant burden of personal measurements, air pollution health studies often estimate exposures using local ambient air monitors. Since outdoor levels do not necessarily reflect personal exposures, we developed the Exposure Model for Individuals (EMI) to improv...

  2. Exposure Modeling of Residential Air Exchange Rates for NEXUS Participants.

    EPA Science Inventory

    Due to cost and participant burden of personal measurements, air pollution health studies often estimate exposures using local ambient air monitors. Since outdoor levels do not necessarily reflect personal exposures, we developed the Exposure Model for Individuals (EMI) to improv...

  3. Hypophosphatemia promotes lower rates of muscle ATP synthesis

    PubMed Central

    Pesta, Dominik H.; Tsirigotis, Dimitrios N.; Befroy, Douglas E.; Caballero, Daniel; Jurczak, Michael J.; Rahimi, Yasmeen; Cline, Gary W.; Dufour, Sylvie; Birkenfeld, Andreas L.; Rothman, Douglas L.; Carpenter, Thomas O.; Insogna, Karl; Petersen, Kitt Falk; Bergwitz, Clemens; Shulman, Gerald I.

    2016-01-01

    Hypophosphatemia can lead to muscle weakness and respiratory and heart failure, but the mechanism is unknown. To address this question, we noninvasively assessed rates of muscle ATP synthesis in hypophosphatemic mice by using in vivo saturation transfer [31P]-magnetic resonance spectroscopy. By using this approach, we found that basal and insulin-stimulated rates of muscle ATP synthetic flux (VATP) and plasma inorganic phosphate (Pi) were reduced by 50% in mice with diet-induced hypophosphatemia as well as in sodium-dependent Pi transporter solute carrier family 34, member 1 (NaPi2a)-knockout (NaPi2a−/−) mice compared with their wild-type littermate controls. Rates of VATP normalized in both hypophosphatemic groups after restoring plasma Pi concentrations. Furthermore, VATP was directly related to cellular and mitochondrial Pi uptake in L6 and RC13 rodent myocytes and isolated muscle mitochondria. Similar findings were observed in a patient with chronic hypophosphatemia as a result of a mutation in SLC34A3 who had a 50% reduction in both serum Pi content and muscle VATP. After oral Pi repletion and normalization of serum Pi levels, muscle VATP completely normalized in the patient. Taken together, these data support the hypothesis that decreased muscle ATP synthesis, in part, may be caused by low blood Pi concentrations, which may explain some aspects of muscle weakness observed in patients with hypophosphatemia.—Pesta, D. H., Tsirigotis, D. N., Befroy, D. E., Caballero, D., Jurczak, M. J., Rahimi, Y., Cline, G. W., Dufour, S., Birkenfeld, A. L., Rothman, D. L., Carpenter, T. O., Insogna, K., Petersen, K. F., Bergwitz, C., Shulman, G. I. Hypophosphatemia promotes lower rates of muscle ATP synthesis. PMID:27338702

  4. Adaptation to Low Temperature Exposure Increases Metabolic Rates Independently of Growth Rates.

    PubMed

    Williams, Caroline M; Szejner-Sigal, Andre; Morgan, Theodore J; Edison, Arthur S; Allison, David B; Hahn, Daniel A

    2016-07-01

    Metabolic cold adaptation is a pattern where ectotherms from cold, high-latitude, or -altitude habitats have higher metabolic rates than ectotherms from warmer habitats. When found, metabolic cold adaptation is often attributed to countergradient selection, wherein short, cool growing seasons select for a compensatory increase in growth rates and development times of ectotherms. Yet, ectotherms in high-latitude and -altitude environments face many challenges in addition to thermal and time constraints on lifecycles. In addition to short, cool growing seasons, high-latitude and - altitude environments are characterized by regular exposure to extreme low temperatures, which cause ectotherms to enter a transient state of immobility termed chill coma. The ability to resume activity quickly after chill coma increases with latitude and altitude in patterns consistent with local adaptation to cold conditions. We show that artificial selection for fast and slow chill coma recovery among lines of the fly Drosophila melanogaster also affects rates of respiratory metabolism. Cold-hardy fly lines, with fast recovery from chill coma, had higher respiratory metabolic rates than control lines, with cold-susceptible slow-recovering lines having the lowest metabolic rates. Fast chill coma recovery was also associated with higher respiratory metabolism in a set of lines derived from a natural population. Although their metabolic rates were higher than control lines, fast-recovering cold-hardy lines did not have faster growth rates or development times than control lines. This suggests that raised metabolic rates in high-latitude and -altitude species may be driven by adaptation to extreme low temperatures, illustrating the importance of moving "Beyond the Mean". PMID:27103615

  5. Combined methodology for estimating dose rates and health effects from exposure to radioactive pollutants

    SciTech Connect

    Dunning, D.E. Jr.; Leggett, R.W.; Yalcintas, M.G.

    1980-12-01

    The work described in the report is basically a synthesis of two previously existing computer codes: INREM II, developed at the Oak Ridge National Laboratory (ORNL); and CAIRD, developed by the Environmental Protection Agency (EPA). The INREM II code uses contemporary dosimetric methods to estimate doses to specified reference organs due to inhalation or ingestion of a radionuclide. The CAIRD code employs actuarial life tables to account for competing risks in estimating numbers of health effects resulting from exposure of a cohort to some incremental risk. The combined computer code, referred to as RADRISK, estimates numbers of health effects in a hypothetical cohort of 100,000 persons due to continuous lifetime inhalation or ingestion of a radionuclide. Also briefly discussed in this report is a method of estimating numbers of health effects in a hypothetical cohort due to continuous lifetime exposure to external radiation. This method employs the CAIRD methodology together with dose conversion factors generated by the computer code DOSFACTER, developed at ORNL; these dose conversion factors are used to estimate dose rates to persons due to radionuclides in the air or on the ground surface. The combination of the life table and dosimetric guidelines for the release of radioactive pollutants to the atmosphere, as required by the Clean Air Act Amendments of 1977.

  6. RATE Exposure Assessment Modules - EXA 408, EXA 409

    EPA Science Inventory

    EXA 408 – Interpreting Biomonitoring Data and Using Pharmacokinetic Modeling in Exposure Assessment Widespread acceptance and use of the CDC's National Health and Nutritional Examination Survey (NHANES) database, which, among other things, reports measured concentrations of...

  7. A hazardous substance exposure prevention rating method for intervention needs assessment and effectiveness evaluation: the Small Business Exposure Index

    PubMed Central

    2009-01-01

    Aims This paper describes the refinement and adaptation to small business of a previously developed method for systematically prioritizing needs for intervention on hazardous substance exposures in manufacturing worksites, and evaluating intervention effectiveness. Methods We developed a checklist containing six unique sets of yes/no variables organized in a 2 × 3 matrix of exposure potential versus exposure protection at three levels corresponding to a simplified hierarchy of controls: materials, processes, and human interface. Each of the six sets of indicator variables was reduced to a high/moderate/low rating. Ratings from the matrix were then combined to generate an exposure prevention 'Small Business Exposure Index' (SBEI) Summary score for each area. Reflecting the hierarchy of controls, material factors were weighted highest, followed by process, and then human interface. The checklist administered by an industrial hygienist during walk-through inspection (N = 149 manufacturing processes/areas in 25 small to medium-sized manufacturing worksites). One area or process per manufacturing department was assessed and rated. A second hygienist independently assessed 36 areas to evaluate inter-rater reliability. Results The SBEI Summary scores indicated that exposures were well controlled in the majority of areas assessed (58% with rating of 1 or 2 on a 6-point scale), that there was some room for improvement in roughly one-third of areas (31% of areas rated 3 or 4), and that roughly 10% of the areas assessed were urgently in need of intervention (rated as 5 or 6). Inter-rater reliability of EP ratings was good to excellent (e.g., for SBEI Summary scores, weighted kappa = 0.73, 95% CI 0.52–0.93). Conclusion The SBEI exposure prevention rating method is suitable for use in small/medium enterprises, has good discriminatory power and reliability, offers an inexpensive method for intervention needs assessment and effectiveness evaluation, and complements

  8. Controlling Item Exposure Rates in a Realistic Adaptive Testing Paradigm.

    ERIC Educational Resources Information Center

    Stocking, Martha L.

    In the context of paper and pencil testing, the frequency of the exposure of items is usually controlled through policies that regulate both the reuse of test forms and the frequency with which a candidate may retake the test. In the context of computerized adaptive testing, where item pools are large and expensive to produce and testing can be on…

  9. Haematopoietic stem cells require a highly regulated protein synthesis rate.

    PubMed

    Signer, Robert A J; Magee, Jeffrey A; Salic, Adrian; Morrison, Sean J

    2014-05-01

    Many aspects of cellular physiology remain unstudied in somatic stem cells, for example, there are almost no data on protein synthesis in any somatic stem cell. Here we set out to compare protein synthesis in haematopoietic stem cells (HSCs) and restricted haematopoietic progenitors. We found that the amount of protein synthesized per hour in HSCs in vivo was lower than in most other haematopoietic cells, even if we controlled for differences in cell cycle status or forced HSCs to undergo self-renewing divisions. Reduced ribosome function in Rpl24(Bst/+) mice further reduced protein synthesis in HSCs and impaired HSC function. Pten deletion increased protein synthesis in HSCs but also reduced HSC function. Rpl24(Bst/+) cell-autonomously rescued the effects of Pten deletion in HSCs; blocking the increase in protein synthesis, restoring HSC function, and delaying leukaemogenesis. Pten deficiency thus depletes HSCs and promotes leukaemia partly by increasing protein synthesis. Either increased or decreased protein synthesis impairs HSC function.

  10. 10 CFR 35.2070 - Records of surveys for ambient radiation exposure rate.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 1 2013-01-01 2013-01-01 false Records of surveys for ambient radiation exposure rate. 35.2070 Section 35.2070 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Records § 35.2070 Records of surveys for ambient radiation exposure rate. A licensee shall retain a record...

  11. 10 CFR 35.2070 - Records of surveys for ambient radiation exposure rate.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 1 2011-01-01 2011-01-01 false Records of surveys for ambient radiation exposure rate. 35.2070 Section 35.2070 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Records § 35.2070 Records of surveys for ambient radiation exposure rate. A licensee shall retain a record...

  12. 10 CFR 35.2070 - Records of surveys for ambient radiation exposure rate.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 1 2012-01-01 2012-01-01 false Records of surveys for ambient radiation exposure rate. 35.2070 Section 35.2070 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Records § 35.2070 Records of surveys for ambient radiation exposure rate. A licensee shall retain a record...

  13. 10 CFR 35.70 - Surveys of ambient radiation exposure rate.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 1 2011-01-01 2011-01-01 false Surveys of ambient radiation exposure rate. 35.70 Section... Requirements § 35.70 Surveys of ambient radiation exposure rate. (a) In addition to the surveys required by Part 20 of this chapter, a licensee shall survey with a radiation detection survey instrument at...

  14. 10 CFR 35.70 - Surveys of ambient radiation exposure rate.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 1 2012-01-01 2012-01-01 false Surveys of ambient radiation exposure rate. 35.70 Section... Requirements § 35.70 Surveys of ambient radiation exposure rate. (a) In addition to the surveys required by Part 20 of this chapter, a licensee shall survey with a radiation detection survey instrument at...

  15. 10 CFR 35.70 - Surveys of ambient radiation exposure rate.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Surveys of ambient radiation exposure rate. 35.70 Section... Requirements § 35.70 Surveys of ambient radiation exposure rate. (a) In addition to the surveys required by Part 20 of this chapter, a licensee shall survey with a radiation detection survey instrument at...

  16. 10 CFR 35.70 - Surveys of ambient radiation exposure rate.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 1 2013-01-01 2013-01-01 false Surveys of ambient radiation exposure rate. 35.70 Section... Requirements § 35.70 Surveys of ambient radiation exposure rate. (a) In addition to the surveys required by Part 20 of this chapter, a licensee shall survey with a radiation detection survey instrument at...

  17. 10 CFR 35.2070 - Records of surveys for ambient radiation exposure rate.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 1 2014-01-01 2014-01-01 false Records of surveys for ambient radiation exposure rate. 35.2070 Section 35.2070 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Records § 35.2070 Records of surveys for ambient radiation exposure rate. A licensee shall retain a record...

  18. 10 CFR 35.70 - Surveys of ambient radiation exposure rate.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 1 2014-01-01 2014-01-01 false Surveys of ambient radiation exposure rate. 35.70 Section... Requirements § 35.70 Surveys of ambient radiation exposure rate. (a) In addition to the surveys required by Part 20 of this chapter, a licensee shall survey with a radiation detection survey instrument at...

  19. 10 CFR 35.2070 - Records of surveys for ambient radiation exposure rate.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Records of surveys for ambient radiation exposure rate. 35.2070 Section 35.2070 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Records § 35.2070 Records of surveys for ambient radiation exposure rate. A licensee shall retain a record...

  20. Microwave-enhanced reaction rates for nanoparticle synthesis.

    PubMed

    Gerbec, Jeffrey A; Magana, Donny; Washington, Aaron; Strouse, Geoffrey F

    2005-11-16

    Microwave reactor methodologies are unique in their ability to be scaled-up without suffering thermal gradient effects, providing a potentially industrially important improvement in nanocrystal synthetic methodology over convective methods. Synthesis of high-quality, near monodispersity nanoscale InGaP, InP, and CdSe have been prepared via direct microwave heating of the molecular precursors rather than convective heating of the solvent. Microwave dielectric heating not only enhances the rate of formation, it also enhances the material quality and size distributions. The reaction rates are influenced by the microwave field and by additives. The final quality of the microwave-generated materials depends on the reactant choice, the applied power, the reaction time, and temperature. CdSe nanocrystals prepared in the presence of a strong microwave absorber exhibit sharp excitonic features and a QY of 68% for microwave-grown materials. InGaP and InP are rapidly formed at 280 degrees C in minutes, yielding clean reactions and monodisperse size distributions that require no size-selective precipitation and result in the highest out of batch quantum efficiency reported to date of 15% prior to chemical etching. The use of microwave (MW) methodology is readily scalable to larger reaction volumes, allows faster reaction times, removes the need for high-temperature injection, and suggests a specific microwave effect may be present in these reactions.

  1. Cosmogenic in situ production of radionuclides: Exposure ages and erosion rates

    NASA Astrophysics Data System (ADS)

    Heisinger, B.; Nolte, E.

    2000-10-01

    Experimental data for the cosmogenic in situ production of radionuclides and its depth dependence are used for two applications, the determination of exposure ages and of erosion rates. Concentrations of the long-lived radionuclides 10Be, 14C and 26Al in quartz are presented as function of exposure age, depth before exposure and erosion rate after exposure. It is shown that the cosmogenic production before exposure can introduce important corrections to the representation without consideration of pre-exposure production. Depth profiles of 10Be, 14C and 26Al in quartz and sulfur, of 36Cl in K 2O, CaCO 3, granite and concrete and of 53Mn in Fe 2O 3 are given as function of erosion rate. Consequences to determinations of neutron fluences in Hiroshima are discussed.

  2. MICROBIAL VOLATILE ORGANIC COMPOUND EMISSION RATES AND EXPOSURE MODEL

    EPA Science Inventory

    This paper presents the results from a study that examined microbial volatile organic compound (MVOC) emissions from six fungi and one bacterial species (Streptomyces spp.) commonly found in indoor environments. Data are presented on peak emission rates from inoculated agar plate...

  3. Measurement of Microbial Activity and Growth in the Ocean by Rates of Stable Ribonucleic Acid Synthesis

    PubMed Central

    Karl, David M.

    1979-01-01

    A relatively simple and extremely sensitive technique for measuring rates of stable ribonucleic acid (RNA) synthesis was devised and applied to bacterial cultures and seawater samples. The procedure is based upon the uptake and incorporation of exogenous radiolabeled adenine into cellular RNA. To calculate absolute rates of synthesis, measurements of the specific radioactivity of the intracellular adenosine 5′-triphosphate pools (precursor to RNA) and of the total amount of radioactivity incorporated into stable cellular RNA per unit time are required. Since the rate of RNA synthesis is positively correlated with growth rate, measurements of RNA synthesis should be extremely useful for estimating and comparing the productivities of microbial assemblages in nature. Adenosine 5′-triphosphate, adenylate energy charge, and rates of stable RNA synthesis have been measured at a station located in the Columbian Basin of the Caribbean Sea. A subsurface peak in RNA synthesis (and therefore growth) was located within the dissolved oxygen minimum zone (450 m), suggesting in situ microbiological utilization of dissolved molecular oxygen. Calculations of the specific rates of RNA synthesis (i.e., RNA synthesis per unit of biomass) revealed that the middepth maximum corresponded to the highest specific rate of growth (420 pmol of adenine incorporated into RNA·day−1) of all depths sampled, including the euphotic zone. The existence of an intermediate depth zone of active microbial growth may be an important site for nutrient regeneration and may serve as a source of reduced carbon for mesopelagic and deep sea environments. PMID:16345461

  4. Analyzing the effects of mechanical and osmotic loading on glycosaminoglycan synthesis rate in cartilaginous tissues.

    PubMed

    Gao, Xin; Zhu, Qiaoqiao; Gu, Weiyong

    2015-02-26

    The glycosaminoglycan (GAG) plays an important role in cartilaginous tissues to support and transmit mechanical loads. Many extracellular biophysical stimuli could affect GAG synthesis by cells. It has been hypothesized that the change of cell volume is a primary mechanism for cells to perceive the stimuli. Experimental studies have shown that the maximum synthesis rate of GAG is achieved at an optimal cell volume, larger or smaller than this level the GAG synthesis rate decreases. Based on the hypothesis and experimental findings in the literature, we proposed a mathematical model to quantitatively describe the cell volume dependent GAG synthesis rate in the cartilaginous tissues. Using this model, we investigated the effects of osmotic loading and mechanical loading on GAG synthesis rate. It is found our proposed mathematical model is able to well describe the change of GAG synthesis rate in isolated cells or in cartilage with variations of the osmotic loading or mechanical loading. This model is important for evaluating the GAG synthesis activity within cartilaginous tissues as well as understanding the role of mechanical loading in tissue growth or degeneration. It is also important for designing a bioreactor system with proper extracellular environment or mechanical loading for growing tissue at the maximum synthesis rate of the extracellular matrix. PMID:25638034

  5. EXPOSURE OF CULTURED MYOCYTES TO ZINC RESULTS IN ALTERED BEAT RATE AND INTERCELLULAR COMMUNICATION.

    EPA Science Inventory

    Exposure of cultured myocytes to zinc results in altered beat rate and intercellular communication

    Graff, Donald W, Devlin, Robert B, Brackhan, Joseph A, Muller-Borer, Barbara J, Bowman, Jill S, Cascio, Wayne E.

    Exposure to ambient air pollution particulate matter (...

  6. Rates and Psychological Effects of Exposure to Family Violence among Sri Lankan University Students

    ERIC Educational Resources Information Center

    Haj-Yahia, Muhammad M.; de Zoysa, Piyanjli

    2008-01-01

    Objectives: The study had two objectives: to examine the rates of exposure to family violence among students in a non-Western society, with Sri Lanka as a case study and to examine the psychological effects of their exposure. Method: Four hundred seventy six medical students in Sri Lanka were surveyed. A self-administered questionnaire was…

  7. Exposure to Community Violence among Arab Youth in Israel: Rates and Characteristics

    ERIC Educational Resources Information Center

    Haj-Yahia, Muhammad M.; Leshem, Becky; Guterman, Neil

    2011-01-01

    The research explored the rates and characteristics of exposure to community violence (CV) and its relevance to several sociodemographic factors among a sample of 833 Arab youth aged 14-18 years residing in diverse residential areas in Israel. Data were collected using a self-report questionnaire. The frequency of exposure to CV during the past 12…

  8. Biosocial Bases of Reactive and Proactive Aggression: The Roles of Community Violence Exposure and Heart Rate

    ERIC Educational Resources Information Center

    Scarpa, Angela; Tanaka, Akiho; Haden, Sara Chiara

    2008-01-01

    In order to more fully understand how individual differences influence adaptation to violence, this study examined the moderating influence of resting heart rate (HR) and HR variability (HRV) between community violence (CV) exposure and child reactive/proactive aggression. Forty 7-13-year-old community children self-reported CV exposure (i.e.,…

  9. VANADIUM EXPOSURE ALTERS SPONTANEOUS BEAT RATE AND GENE EXPRESSION OF CULTURED CARDIAC MYOCYTES

    EPA Science Inventory

    Ambient air pollution particulate matter (PM) exposure is associated with increased morbidity and mortality. Recent toxicological studies report PM-induced changes in a number of cardiac parameters, including heart rate variability, arrhythmias, repolarization, and internal defib...

  10. Comparison of hurricane exposure methods and associations with county fetal death rates, adjusting for environmental quality

    EPA Science Inventory

    Adverse effects of hurricanes are increasing as coastal populations grow and events become more severe. Hurricane exposure during pregnancy can influence fetal death rates through mechanisms related to healthcare, infrastructure disruption, nutrition, and injury. Estimation of hu...

  11. Distribution of gamma exposure rates in a reactor effluent stream flood plain system.

    PubMed

    Gladden, J B; Brown, K L; Smith, M H; Towns, A

    1985-01-01

    Ground-level gamma dosimetry surveys were conducted along the length of a radiocesium-contaminated reactor effluent stream flood plain system to determine the extent and patterns of isotope distribution over a decade after reactor releases were stopped. The maximum mean exposure rates were found at upstream locations near the source of the contamination and in a downstream sedimentary delta. Gamma exposure rates were not uniformly distributed and high exposure rates were generally restricted to small areas of the flood plain. There was little similarity in either the spatial distribution or magnitudes of maximum gamma exposure rates across flood plains along the stream. Frequency the measured exposure rates tended to be highly skewed and most closely approximated the log-normal distribution in most areas along the stream. However, the complex and changing patterns of dose distributions strongly affected the ability to predict the probability of encountering unusually high exposure rates. Complex statistical and distributional models are required to provide precise descriptions of the dosimetry environment in such complex ecosystems and different models could be required on a site-by-site basis.

  12. Lung cancer risk at low radon exposure rates in German uranium miners

    PubMed Central

    Kreuzer, M; Fenske, N; Schnelzer, M; Walsh, L

    2015-01-01

    Background: A determination of the risk of lung cancer at low levels of radon exposure is important for occupational radiation protection. Methods: The risk of death from lung cancer at low radon exposure rates was investigated in the subcohort of 26 766 German uranium miners hired in 1960 or later. Results: A clear association between lung cancer mortality (n=334 deaths) and cumulative exposure to radon in working level months (WLM) was found. The excess relative risk per WLM was 0.013 (95% confidence intervals: 0.007; 0.021). Conclusions: The present findings provide strong evidence for an increased lung cancer risk after long-term exposure to low radon exposure rates among Wismut miners. The results are compatible to those from residential radon studies and miner studies restricted to low levels. PMID:26393888

  13. Exposure to Silver Nanoparticles Inhibits Selenoprotein Synthesis and the Activity of Thioredoxin Reductase

    PubMed Central

    Srivastava, Milan; Singh, Sanjay

    2011-01-01

    Background: Silver nanoparticles (AgNPs) and silver (Ag)-based materials are increasingly being incorporated into consumer products, and although humans have been exposed to colloidal Ag in many forms for decades, this rise in the use of Ag materials has spurred interest into their toxicology. Recent reports have shown that exposure to AgNPs or Ag ions leads to oxidative stress, endoplasmic reticulum stress, and reduced cell proliferation. Previous studies have shown that Ag accumulates in tissues as silver sulfides (Ag2S) and silver selenide (Ag2Se). Objectives: In this study we investigated whether exposure of cells in culture to AgNPs or Ag ions at subtoxic doses would alter the effective metabolism of selenium, that is, the incorporation of selenium into selenoproteins. Methods: For these studies we used a keratinocyte cell model (HaCat) and a lung cell model (A549). We also tested (in vitro, both cellular and chemical) whether Ag ions could inhibit the activity of a key selenoenzyme, thioredoxin reductase (TrxR). Results: We found that exposure to AgNPs or far lower levels of Ag ions led to a dose-dependent inhibition of selenium metabolism in both cell models. The synthesis of protein was not altered under these conditions. Exposure to nanomolar levels of Ag ions effectively blocked selenium metabolism, suggesting that Ag ion leaching was likely the mechanism underlying observed changes during AgNP exposure. Exposure likewise inhibited TrxR activity in cultured cells, and Ag ions were potent inhibitors of purified rat TrxR isoform 1 (cytosolic) (TrxR1) enzyme. Conclusions: Exposure to AgNPs leads to the inhibition of selenoprotein synthesis and inhibition of TrxR1. Further, we propose these two sites of action comprise the likely mechanism underlying increases in oxidative stress, increases endoplasmic reticulum stress, and reduced cell proliferation during exposure to Ag. PMID:21965219

  14. Cypermethrin exposure during puberty disrupts testosterone synthesis via downregulating StAR in mouse testes.

    PubMed

    Wang, Hua; Wang, Qun; Zhao, Xian-Feng; Liu, Ping; Meng, Xiu-Hong; Yu, Tao; Ji, Yan-Li; Zhang, Heng; Zhang, Cheng; Zhang, Ying; Xu, De-Xiang

    2010-01-01

    Cypermethrin is a widely used synthetic pyrethroid insecticide. Previous studies showed that cypermethrin significantly decreased the fertility and reduced the number of implantation sites and viable fetuses in females impregnated by males exposed to cypermethrin. As yet, little is known about the mechanism of cypermethrin-induced reproductive toxicity. In the present study, we investigated the effects of cypermethrin exposure during puberty on steroidogenesis in mice. Young male mice were administered with cypermethrin (25 mg/kg) by gavage daily from postnatal day (PND) 35 to PND70. Results showed that the level of serum and testicular testosterone (T) was markedly decreased in cypermethrin-treated mice. Additional experiment showed that cypermethrin exposure during puberty markedly downregulated mRNA level of steroidogenic acute regulatory protein (StAR) in testes. Correspondingly, protein level of testicular StAR was significantly decreased in cypermethrin-treated mice. Cypermethrin exposure during puberty did not affect the number of Leydig cells in testes. Although cypermethrin exposure during puberty did not affect the weight of testes and epididymides, the number of sperm in the cauda epididymides was significantly decreased in cypermethrin-treated mice. Taken together, these results indicate that cypermethrin exposure during puberty significantly disrupts T synthesis via downregulating the expression of testicular StAR. The decreased T synthesis might be associated with cypermethrin-induced impairment in spermatogenesis in mice.

  15. Determination of specific growth rate by measurement of specific rate of ribosome synthesis in growing and nongrowing cultures of Acinetobacter calcoaceticus.

    PubMed

    Cutter, Matthew R; Stroot, Peter G

    2008-02-01

    RT-RiboSyn measures the specific rate of ribosome synthesis in distinct microbial populations by measuring the generation rate of precursor 16S rRNA relative to that of mature 16S rRNA when precursor 16S rRNA processing is inhibited. Good agreement was demonstrated between specific rate of ribosome synthesis and specific growth rate of Acinetobacter calcoaceticus.

  16. Effect of Repeated Evaluation and Repeated Exposure on Acceptability Ratings of Sentences

    ERIC Educational Resources Information Center

    Zervakis, Jennifer; Mazuka, Reiko

    2013-01-01

    This study investigated the effect of repeated evaluation and repeated exposure on grammatical acceptability ratings for both acceptable and unacceptable sentence types. In Experiment 1, subjects in the Experimental group rated multiple examples of two ungrammatical sentence types (ungrammatical binding and double object with dative-only verb),…

  17. Review of Air Exchange Rate Models for Air Pollution Exposure Assessments

    EPA Science Inventory

    A critical aspect of air pollution exposure assessments is estimation of the air exchange rate (AER) for various buildings, where people spend their time. The AER, which is rate the exchange of indoor air with outdoor air, is an important determinant for entry of outdoor air pol...

  18. Rating locomotive crew diesel emission exposure profiles using statistics and Bayesian Decision Analysis.

    PubMed

    Hewett, Paul; Bullock, William H

    2014-01-01

    For more than 20 years CSX Transportation (CSXT) has collected exposure measurements from locomotive engineers and conductors who are potentially exposed to diesel emissions. The database included measurements for elemental and total carbon, polycyclic aromatic hydrocarbons, aromatics, aldehydes, carbon monoxide, and nitrogen dioxide. This database was statistically analyzed and summarized, and the resulting statistics and exposure profiles were compared to relevant occupational exposure limits (OELs) using both parametric and non-parametric descriptive and compliance statistics. Exposure ratings, using the American Industrial Health Association (AIHA) exposure categorization scheme, were determined using both the compliance statistics and Bayesian Decision Analysis (BDA). The statistical analysis of the elemental carbon data (a marker for diesel particulate) strongly suggests that the majority of levels in the cabs of the lead locomotives (n = 156) were less than the California guideline of 0.020 mg/m(3). The sample 95th percentile was roughly half the guideline; resulting in an AIHA exposure rating of category 2/3 (determined using BDA). The elemental carbon (EC) levels in the trailing locomotives tended to be greater than those in the lead locomotive; however, locomotive crews rarely ride in the trailing locomotive. Lead locomotive EC levels were similar to those reported by other investigators studying locomotive crew exposures and to levels measured in urban areas. Lastly, both the EC sample mean and 95%UCL were less than the Environmental Protection Agency (EPA) reference concentration of 0.005 mg/m(3). With the exception of nitrogen dioxide, the overwhelming majority of the measurements for total carbon, polycyclic aromatic hydrocarbons, aromatics, aldehydes, and combustion gases in the cabs of CSXT locomotives were either non-detects or considerably less than the working OELs for the years represented in the database. When compared to the previous American

  19. Effect of repeated evaluation and repeated exposure on acceptability ratings of sentences.

    PubMed

    Zervakis, Jennifer; Mazuka, Reiko

    2013-12-01

    This study investigated the effect of repeated evaluation and repeated exposure on grammatical acceptability ratings for both acceptable and unacceptable sentence types. In Experiment 1, subjects in the Experimental group rated multiple examples of two ungrammatical sentence types (ungrammatical binding and double object with dative-only verb), and two difficult to process sentence types [center-embedded (2) and garden path ambiguous relative], along with matched grammatical/non-difficult sentences, before rating a final set of experimental sentences. Subjects in the control group rated unrelated sentences during the exposure period before rating the experimental sentences. Subjects in the Experimental group rated both grammatical and ungrammatical sentences as more acceptable after repeated evaluation than subjects in the Control group. In Experiment 2, subjects answered a comprehension question after reading each sentence during the exposure period. Subjects in the experimental group rated garden path and center-embedded (1) sentences as higher in acceptability after comprehension exposure than subjects in the control group. The results are consistent with increased fluency of comprehension being misattributed as a change in acceptability.

  20. Effect of repeated evaluation and repeated exposure on acceptability ratings of sentences.

    PubMed

    Zervakis, Jennifer; Mazuka, Reiko

    2013-12-01

    This study investigated the effect of repeated evaluation and repeated exposure on grammatical acceptability ratings for both acceptable and unacceptable sentence types. In Experiment 1, subjects in the Experimental group rated multiple examples of two ungrammatical sentence types (ungrammatical binding and double object with dative-only verb), and two difficult to process sentence types [center-embedded (2) and garden path ambiguous relative], along with matched grammatical/non-difficult sentences, before rating a final set of experimental sentences. Subjects in the control group rated unrelated sentences during the exposure period before rating the experimental sentences. Subjects in the Experimental group rated both grammatical and ungrammatical sentences as more acceptable after repeated evaluation than subjects in the Control group. In Experiment 2, subjects answered a comprehension question after reading each sentence during the exposure period. Subjects in the experimental group rated garden path and center-embedded (1) sentences as higher in acceptability after comprehension exposure than subjects in the control group. The results are consistent with increased fluency of comprehension being misattributed as a change in acceptability. PMID:23179954

  1. Emesis as a Screening Diagnostic for Low Dose Rate (LDR) Total Body Radiation Exposure.

    PubMed

    Camarata, Andrew S; Switchenko, Jeffrey M; Demidenko, Eugene; Flood, Ann B; Swartz, Harold M; Ali, Arif N

    2016-04-01

    Current radiation disaster manuals list the time-to-emesis (TE) as the key triage indicator of radiation dose. The data used to support TE recommendations were derived primarily from nearly instantaneous, high dose-rate exposures as part of variable condition accident databases. To date, there has not been a systematic differentiation between triage dose estimates associated with high and low dose rate (LDR) exposures, even though it is likely that after a nuclear detonation or radiologic disaster, many surviving casualties would have received a significant portion of their total exposure from fallout (LDR exposure) rather than from the initial nuclear detonation or criticality event (high dose rate exposure). This commentary discusses the issues surrounding the use of emesis as a screening diagnostic for radiation dose after LDR exposure. As part of this discussion, previously published clinical data on emesis after LDR total body irradiation (TBI) is statistically re-analyzed as an illustration of the complexity of the issue and confounding factors. This previously published data includes 107 patients who underwent TBI up to 10.5 Gy in a single fraction delivered over several hours at 0.02 to 0.04 Gy min. Estimates based on these data for the sensitivity of emesis as a screening diagnostic for the low dose rate radiation exposure range from 57.1% to 76.6%, and the estimates for specificity range from 87.5% to 99.4%. Though the original data contain multiple confounding factors, the evidence regarding sensitivity suggests that emesis appears to be quite poor as a medical screening diagnostic for LDR exposures. PMID:26910032

  2. Heart Rate, Stress, and Occupational Noise Exposure among Electronic Waste Recycling Workers.

    PubMed

    Burns, Katrina N; Sun, Kan; Fobil, Julius N; Neitzel, Richard L

    2016-01-01

    Electronic waste (e-waste) is a growing occupational and environmental health issue around the globe. E-waste recycling is a green industry of emerging importance, especially in low-and middle-income countries where much of this recycling work is performed, and where many people's livelihoods depend on this work. The occupational health hazards of e-waste recycling have not been adequately explored. We performed a cross-sectional study of noise exposures, heart rate, and perceived stress among e-waste recycling workers at a large e-waste site in Accra, Ghana. We interviewed 57 workers and continuously monitored their individual noise exposures and heart rates for up to 24 h. More than 40% of workers had noise exposures that exceeded recommended occupational (85 dBA) and community (70 dBA) noise exposure limits, and self-reported hearing difficulties were common. Workers also had moderate to high levels of perceived stress as measured via Cohen's Perceived Stress Scale, and reported a variety of symptoms that could indicate cardiovascular disease. Noise exposures were moderately and significantly correlated with heart rate (Spearman's ρ 0.46, p < 0.001). A mixed effects linear regression model indicated that a 1 dB increase in noise exposure was associated with a 0.17 increase in heart rate (p-value = 0.01) even after controlling for work activities, age, smoking, perceived stress, and unfavorable physical working conditions. These findings suggest that occupational and non-occupational noise exposure is associated with elevations in average heart rate, which may in turn predict potential cardiovascular damage. PMID:26797626

  3. Heart Rate, Stress, and Occupational Noise Exposure among Electronic Waste Recycling Workers.

    PubMed

    Burns, Katrina N; Sun, Kan; Fobil, Julius N; Neitzel, Richard L

    2016-01-19

    Electronic waste (e-waste) is a growing occupational and environmental health issue around the globe. E-waste recycling is a green industry of emerging importance, especially in low-and middle-income countries where much of this recycling work is performed, and where many people's livelihoods depend on this work. The occupational health hazards of e-waste recycling have not been adequately explored. We performed a cross-sectional study of noise exposures, heart rate, and perceived stress among e-waste recycling workers at a large e-waste site in Accra, Ghana. We interviewed 57 workers and continuously monitored their individual noise exposures and heart rates for up to 24 h. More than 40% of workers had noise exposures that exceeded recommended occupational (85 dBA) and community (70 dBA) noise exposure limits, and self-reported hearing difficulties were common. Workers also had moderate to high levels of perceived stress as measured via Cohen's Perceived Stress Scale, and reported a variety of symptoms that could indicate cardiovascular disease. Noise exposures were moderately and significantly correlated with heart rate (Spearman's ρ 0.46, p < 0.001). A mixed effects linear regression model indicated that a 1 dB increase in noise exposure was associated with a 0.17 increase in heart rate (p-value = 0.01) even after controlling for work activities, age, smoking, perceived stress, and unfavorable physical working conditions. These findings suggest that occupational and non-occupational noise exposure is associated with elevations in average heart rate, which may in turn predict potential cardiovascular damage.

  4. Heart Rate, Stress, and Occupational Noise Exposure among Electronic Waste Recycling Workers

    PubMed Central

    Burns, Katrina N.; Sun, Kan; Fobil, Julius N.; Neitzel, Richard L.

    2016-01-01

    Electronic waste (e-waste) is a growing occupational and environmental health issue around the globe. E-waste recycling is a green industry of emerging importance, especially in low-and middle-income countries where much of this recycling work is performed, and where many people’s livelihoods depend on this work. The occupational health hazards of e-waste recycling have not been adequately explored. We performed a cross-sectional study of noise exposures, heart rate, and perceived stress among e-waste recycling workers at a large e-waste site in Accra, Ghana. We interviewed 57 workers and continuously monitored their individual noise exposures and heart rates for up to 24 h. More than 40% of workers had noise exposures that exceeded recommended occupational (85 dBA) and community (70 dBA) noise exposure limits, and self-reported hearing difficulties were common. Workers also had moderate to high levels of perceived stress as measured via Cohen’s Perceived Stress Scale, and reported a variety of symptoms that could indicate cardiovascular disease. Noise exposures were moderately and significantly correlated with heart rate (Spearman’s ρ 0.46, p < 0.001). A mixed effects linear regression model indicated that a 1 dB increase in noise exposure was associated with a 0.17 increase in heart rate (p-value = 0.01) even after controlling for work activities, age, smoking, perceived stress, and unfavorable physical working conditions. These findings suggest that occupational and non-occupational noise exposure is associated with elevations in average heart rate, which may in turn predict potential cardiovascular damage. PMID:26797626

  5. Adrenal catecholamine synthesis rate changes induced by combined thermal and immobilization stress in fed and 24 hour fasted rats.

    PubMed

    Bargiel, Z; Nowicka, H

    1989-01-01

    The combined stress of acute immobilization (IM) at high and low ambient temperature has been used to determine its influence on adrenal catecholamine (CA) content assassed histofluorimetrically in fed and 24 hour fasted rats. The general course of changes obtained after the arrangement of adrenal strips deriving from the adrenals of rats exposed to cold and IM stress (CIMS) at +10 degrees C to -25 degrees C during the different time fragments presented the adrenal CA depletion events followed sometimes by the adrenal CA content increase after the longer stress exposure or/and stronger CIMS and WIMS conditions. It was found that this depletion-stimulated increase of adrenal Ca synthesis rate had been accelerated in 24 h fasted rats compared to satiated ones exposed to the same stress conditions, especially after the CIMS exposure. Moreover the survival time duration at first lethal temperature (-5 degrees C and +45 degrees C) was significantly higher in fasted rats. The possible hypothalamic regulation of adrenal CA synthesis rate accordingly to the actual metabolism needs and beta-adrenoceptor sensitivity changes depending on satiety state have been discussed and the necessity of further investigations concerning the specificity of stress-induced metabolism changes in 24 h starved rats has been suggested.

  6. Heart rate variability and particulate exposure in vehicle maintenance workers: a pilot study.

    PubMed

    Eninger, Robert M; Rosenthal, Frank S

    2004-08-01

    The association between occupational exposure to PM(2.5) and heart rate variability was investigated in a repeated measures, longitudinal study of vehicle maintenance workers occupationally exposed to automobile emissions. Five subjects were monitored for occupational exposure to fine particulate matter (PM(2.5)) on 6 workdays using an aerosol photometer, validated with side-by-side sampling with a gravimetric method. End-of-day heart rate variability statistics were derived using short-term electrocardiogram recordings for each participant. Workplace carbon monoxide and outdoor, ambient fine particulate matter were also monitored. Regression statistics were used to investigate associations between same-day PM(2.5) levels and heart rate variability statistics using mixed-effects multiple regression of pooled data. No statistically significant associations were observed between occupational PM(2.5) and measures of heart rate variability. A statistically significant increase in total spectral power was associated with ambient PM(2.5) (p < 0.05). The data suggest a threshold below which no degradation in cardiac autonomic control of healthy workers occurs when challenged by occupational PM(2.5) exposure. This study was limited in population, exposure level, and type of particulate exposures. Additional studies are recommended on broader occupational populations. PMID:15238301

  7. Heart rate variability and particulate exposure in vehicle maintenance workers: a pilot study.

    PubMed

    Eninger, Robert M; Rosenthal, Frank S

    2004-08-01

    The association between occupational exposure to PM(2.5) and heart rate variability was investigated in a repeated measures, longitudinal study of vehicle maintenance workers occupationally exposed to automobile emissions. Five subjects were monitored for occupational exposure to fine particulate matter (PM(2.5)) on 6 workdays using an aerosol photometer, validated with side-by-side sampling with a gravimetric method. End-of-day heart rate variability statistics were derived using short-term electrocardiogram recordings for each participant. Workplace carbon monoxide and outdoor, ambient fine particulate matter were also monitored. Regression statistics were used to investigate associations between same-day PM(2.5) levels and heart rate variability statistics using mixed-effects multiple regression of pooled data. No statistically significant associations were observed between occupational PM(2.5) and measures of heart rate variability. A statistically significant increase in total spectral power was associated with ambient PM(2.5) (p < 0.05). The data suggest a threshold below which no degradation in cardiac autonomic control of healthy workers occurs when challenged by occupational PM(2.5) exposure. This study was limited in population, exposure level, and type of particulate exposures. Additional studies are recommended on broader occupational populations.

  8. Influence of exposure time on the biotransformation rate of benzo(a)anthracene in fish

    SciTech Connect

    Maagd, P.G.J. de; Poorte, J. de; Sijm, D.T.H.M.; Opperhuizen, A.

    1995-12-31

    Biotransformation of PAH can yield in the formation of carcinogenic metabolites, therefore, determining the rate at which metabolites are formed is of importance to risk assessment. Biotransformation rates can be affected by inducing agents, hormonal status, temperature etc. To determine if biotransformation rates of PAH are influenced by auto-induction, juvenile fathead minnows were exposed to benzo(a)anthracene in water for various exposure times. After exposure for 5, 10, 24, 72, 168 or 336 hours no significant differences between biotransformation rates were found. The variation within each biotransformation rate was less than 20%. From these findings it is concluded that auto-induction by benzo(a)anthracene does not occur in fathead minnow.

  9. Dose-rate conversion factors for external exposure to photons and electrons

    SciTech Connect

    Kocher, D.C.

    1981-08-01

    Dose-rate conversion factors for external exposure to photons and electrons have been calculated for approximately 500 radionuclides of potential importance in environmental radiological assessments. The dose-rate factors were obtained using the DOSFACTER computer code. The results given in this report incorporate calculation of electron dose-rate factors for radiosensitive tissues of the skin, improved estimates of organ dose-rate factors for photons, based on organ doses for monoenergetic sources at the body surface of an exposed individual, and the spectra of scattered photons in air from monoenergetic sources in an infinite, uniformly contaminated atmospheric cloud, calculation of dose-rate factors for other radionuclides in addition to those of interest in the nuclear fuel cycle, and incorporation of updated radioactive decay data for all radionuclides. Dose-rate factors are calculated for three exposure modes - immersion in contaminated air, immersion in contaminated water, and exposure at a height of 1 m above a contaminated ground surface. The report presents the equations used to calculate the external dose-rate factors for photons and electrons, documentation of the revised DOSFACTER computer code, and a complete tabulation of the calculated dose-rate factors. 30 refs., 12 figs.

  10. Measurement of environmental radiation exposure rates from Vernita, Hanford Reach, and Richland area shores. Addendum 1

    SciTech Connect

    Cooper, A.T.

    1995-02-01

    Environmental radiation exposure rate measurements are taken on and around the Hanford Site for Pacific Northwest Laboratory`s Hanford Site Surface Environmental Surveillance Project. In 1992, environmental radiation exposure rate measurements were taken from shoreline and island areas ranging from Vernita, along the Hanford Reach, down to the Richland Pumphouse. Measurements were taken primarily at locations known or expected to have elevated exposure rates as determined by examination of aerial photographs depicting radiation exposure measurements. Results from the 1992 survey indicated radiation exposure rates taken from the Hanford Reach area were elevated in comparison to the measurements taken from the Vernita area with ranges of 8 to 28 {mu}R/hr and 4 to 11 {mu}R/hr, respectively. In January 1994, additional shoreline radiation exposure rate measurements were taken from the Vernita, Hanford Reach, and Richland areas to determine the relationship of radiation exposure rates along the Richland area shores when compared to Vernita and Hanford Reach area exposure rates (measurements along the Richland area were not collected during the 1992 survey). This report discusses the 1994 results and is an addendum to the report that discussed the 1992 survey. An analysis of variance indicated a significant location interaction at a p-value of 0.0014. To determine differences between paried locations a post-hoc comparison of location means was performed on log transformed data using the Scheff{acute e}`s F-test. This test indicated a significant difference between Hanford Reach and Richland area means with a mean difference of 0.075 /{mu}R/hr and a p-value of 0.0014. No significant difference was found between Hanford Reach and Vernita area means: The mean difference was 0.031 {mu}R/hr and the p-value was 0.3138. No significant difference was found between Vernita and Richland area means with a mean difference of 0.044 {mu}R/hr and a p-value of 0.1155.

  11. Pubertal cadmium exposure impairs testicular development and spermatogenesis via disrupting testicular testosterone synthesis in adult mice.

    PubMed

    Ji, Yan-Li; Wang, Hua; Liu, Ping; Wang, Qun; Zhao, Xian-Feng; Meng, Xiu-Hong; Yu, Tao; Zhang, Heng; Zhang, Cheng; Zhang, Ying; Xu, De-Xiang

    2010-04-01

    Cadmium (Cd) is a well-known testicular toxicant. However, the effects of pubertal Cd exposure on testicular development and spermatogenesis remained to be elucidated. The present study investigated the effects of pubertal Cd exposure on testicular development and spermatogenesis. Male CD-1 mice were intraperitoneally injected with CdCl(2) (1mg/kg) daily from postnatal day 35 (PND35) to PND70. As expected, pubertal Cd exposure significantly decreased the number of spermatozoa in epididymides. In addition, pubertal Cd exposure markedly reduced the weights of testes, epididymides and prostate and seminal vesicle in adult mice. A significant decrease in serum and testicular testosterone (T) was observed in mice exposed to Cd during puberty. Moreover, pubertal Cd exposure markedly reduced mRNA and protein levels of testicular StAR, P450scc, P450(17alpha) and 17beta-HSD. Taken together, these results suggest that the decreased testicular T synthesis might partially contribute to pubertal Cd-induced impairment on testicular development and spermatogenesis in mice. PMID:19897027

  12. Relationship of lipogenic enzyme activities to the rate of rat liver fatty acid synthesis

    SciTech Connect

    Nelson, G.; Kelley, D.; Schmidt, P.; Virk, S.; Serrato, C.

    1986-05-01

    The mechanism by which diet regulates liver lipogenesis is unclear. Here the authors report how dietary alterations effect the activities of key enzymes of fatty acid (FA) synthesis. Male Sprague-Dawley rats, 400-500 g, were fasted for 48h and then refed a fat-free, high carbohydrate (HC) diet (75% cal. from sucrose) for 0,3,9,24 and 48h, or refed a HC diet for 48h, then fed a high-fat (HF) diet (44% cal. from corn oil) for 3,9,24 and 48h. The FA synthesis rate and the activities of acetyl CoA carboxylase (AC), fatty acid synthase (FAS), ATP citrate lyase (CL), and glucose 6-phosphate dehydrogenase (G6PDH) were determined in the livers. FA synthesis was assayed with /sup 3/H/sub 2/O, enzyme activities were measured spectrophotometrically except for AC which was assayed with /sup 14/C-bicarbonate. There was no change in the activity of AC during fasting or on the HC diet. Fasting decreased the rate of FA synthesis by 25% and the activities of FAS and CL by 50%; refeeding the HC diet induced parallel changes in FA synthesis and the activities of FAS, CL, and G6PDH. After 9h on the HF diet, FA synthesis had decreased sharply, AC activity increased significantly while no changes were detected in the other activities. Subsequently FA synthesis did not change while the activities of the enzymes decreased slowly. These enzymes did not appear to regulate FA synthesis during inhibition of lipogenesis, but FAS, CL or G6PDH may be rate limiting in the induction phase. Other key factors may regulate FA synthesis during dietary alterations.

  13. Effect of acute exposure to ozone on heart rate and blood pressure of the conscious rat

    SciTech Connect

    Uchiyama, I.; Simomura, Y.; Yokoyama, E.

    1985-12-01

    Electrocardiogram and arterial blood pressure in conscious and unrestrained rats of various ages were recorded during a 3-hr exposure to filtered air or 1 ppm ozone (O/sub 3/). In general, heart rate and mean arterial blood pressure of rats significantly decreased during exposure to O/sub 3/, whereas these functional parameters remained almost stable during exposure to filtered air. Heart rate usually reached a plateau during the exposure to O/sub 3/. Additionally, PR interval and QRS complex significantly increased and premature atrial contraction and incomplete A-V block were frequently observed during the exposure to O/sub 3/. These circulatory effects of O/sub 3/ were more markedly manifested by rats 11 weeks old than either those 8 or 4 weeks old. On the other hand, no significant difference in the circulatory responses was observed between male and female rats. These circulatory effects of O/sub 3/ may be significant from the viewpoint of health effects, although its mechanisms remain unsolved.

  14. Compendium and synthesis of bacterial manganese reduction rates

    NASA Astrophysics Data System (ADS)

    Bandstra, Joel Z.; Ross, Daniel E.; Brantley, Susan L.; Burgos, William D.

    2011-01-01

    We have compiled time-series concentration data for the biological reduction of manganese(III/IV) published between 1985 and 2004 and fit these data with a simple hyperbolic rate expression or, when appropriate, one of its limiting forms. The compiled data and rate constants are available in Electronic Annex EA-1. The zero- and first-order rate constants appear to follow a log-normal distribution that could be used, for example, in predictive modeling of Mn-oxide reduction in a reactive transport scenario. We have also included details of the experimental procedures used to generate each time-series data-set in our compilation. These meta-data—mostly pertaining to the type and concentration of micro-organism, electron donor, and electron acceptor—enable us to examine the rate data for trends. We have computed a number of rudimentary, mono-variate statistics on the compiled data with the hope of stimulating both more detailed statistical analyses of the data and new experiments to fill gaps in the existing data-set. We have also analyzed the data with parametric models based on the log-normal distribution and rate equations that are hyperbolic in the concentration of cells and Mn available for reduction. This parametric analysis allows us to provide best estimates of zero- and first-order rate constants both ignoring and accounting for the meta-data.

  15. Pain Scores and Exposure Rates After Polypropylene Mesh for Pelvic Organ Prolapse

    PubMed Central

    Illston, Jana; Garris, Jeffrey; Richter, Holly; Wheeler, Thomas

    2016-01-01

    Objectives To characterize pain and exposure after Prolift® placement and identify risk factors. Methods A case series of women who underwent Prolift® vaginal mesh were surveyed. Pain was assessed using a Visual Analog Scale. Exposure was evaluated clinically. Results Of 183 eligible patients, 160 completed the survey, and 45 returned for examination. Mean preoperative pain score was 0.97 and postoperative was 1.35 (p=0.12). Pre and postoperative pain scores by compartment were: anterior (1.34 vs 1.25, mean change −0.09, p-value=0.84), posterior (1.30 vs 1.56, mean change 0.26, p-value=0.72), total (0.63 vs 1.34, mean change 0.71, p-value=0.05). Graft exposure was confirmed in 23 of 183 patients (12.6%), although as asymptomatic patients were not examined, the true exposure rate may be under-estimated. Hematoma formation is independently associated with mesh exposure, adjusted OR=18.4 (95%CI 3.4-147.4, p-value =0.01). Conclusion While pain scores did not increase overall, there was a trend towards increased pain score in the patients with total (anterior and posterior) Prolift®. Hematoma formation significantly associated with mesh exposure. PMID:26630890

  16. Potential radiological exposure rates resulting from hypothetical dome failure at Tank W-10

    SciTech Connect

    Not Available

    1994-07-01

    The main plant area at Oak Ridge National Laboratory (ORNL) contains 12 buried Gunite tanks that were used for the storage and transfer of liquid radioactive waste. Although the tanks are no longer in use, they are known to contain some residual contaminated sludges and liquids. In the event of an accidental tank dome failure, however unlikely, the liquids, sludges, and radioactive contaminants within the tank walls themselves could create radiation fields and result in above-background exposures to workers nearby. This Technical Memorandum documents a series of calculations to estimate potential radiological exposure rates and total exposures to workers in the event of a hypothetical collapse of a Gunite tank dome. Calculations were performed specifically for tank W-10 because it contains the largest radioactivity inventory (approximately half of the total activity) of all the Gunite tanks. These calculations focus only on external, direct gamma exposures for prescribed, hypothetical exposure scenarios and do not address other possible tank failure modes or routes of exposure. The calculations were performed with established, point-kernel gamma ray modeling codes.

  17. Effects of exposure time during flight maneuvers on passenger subjective comfort rating

    NASA Technical Reports Server (NTRS)

    Brown, V. J.

    1975-01-01

    The effects were investigated of length of exposure time to a flight maneuver environment on subjective passenger evaluation of ride comfort. Four statistical analysis tests were performed on ride comfort ratings obtained during one two-hour test flight wherein eleven test subjects were exposed to two identical programmed sequences of twenty four flight segments which covered a wide range of maneuver conditions. The results of the analysis indicate that, for over ninety five percent of the segments, there is no significant change in the test subjects comfort ratings of identical segments spaced one hour apart. These results are in contrast to those found in previous studies involving a vibration environment, rather than flight maneuver environment, where increased exposure-time was found to cause a degradation of ride comfort ratings.

  18. Colorectal Cancer Screening Rates Increased after Exposure to the Patient-Centered Medical Home (PCMH)

    PubMed Central

    Green, Beverly B.; Anderson, Melissa L.; Chubak, Jessica; Baldwin, Laura Mae; Tuzzio, Leah; Catz, Sheryl; Cole, Alison; Vernon, Sally W.

    2016-01-01

    Objective The patient-centered medical home (PCMH) includes comprehensive chronic illness and preventive services, including identifying patients who are overdue for colorectal cancer screening (CRCS). The association between PCMH implementation and CRCS during the Systems of Support to Increase Colorectal Cancer Screening Trial (SOS) is described. Methods The SOS enrolled 4664 patients from 21 clinics from August 2008 to November 2009. Patients were randomized to usual care, mailed fecal kits, kits plus brief assistance, or kits plus assistance and navigation. A PCMH model that included a workflow for facilitating CRCS was implemented at all study clinics in late 2009. Patients enrolled early had little exposure to the PCMH, whereas patients enrolled later were exposed during most of their first year in the trial. Logistic regression models were used to assess the association between PCMH exposure and CRCS. Results Usual care patients with ≥8 months in the PCMH had higher CRCS rates than those with ≤4 months in the PCMH (adjusted difference, 10.1%; 95% confidence interval, 5.7–14.6). SOS interventions led to significant increases in CRCS, but the magnitude of effect was attenuated by exposure to the PCMH (P for interaction = .01). Conclusion Exposure to a PCMH was associated with higher CRCS rates. Automated mailed and centrally delivered stepped interventions increased CRCS rates, even in the presence of a PCMH. (J Am Board Fam Med 2016;29:191–200.) PMID:26957375

  19. The rates and characteristics of the exposure of Palestinian youth to community violence.

    PubMed

    Haj-Yahia, Muhammad M; Leshem, Becky; Guterman, Neil B

    2013-07-01

    The article presents the results of a study that explored the rates and characteristics of exposure to community violence (CV) and its relevance to several sociodemographic factors among a sample of 1,930 Palestinian youth (1,018 girls and 912 boys), aged 12 to 19 years residing in diverse residential areas in the West Bank and East Jerusalem. Data were collected using a self-report questionnaire. The frequency of boys' exposure to CV during the previous 12 months was significantly higher than among girls. The frequency of witnessing CV during that period was higher than the frequency of personally experiencing CV, and exposure to mild CV incidents during that period was higher than the frequency of exposure to severe CV incidents during the same period, with no significant relationship to sociodemographic factors. Participants reported higher rates of witnessing most CV incidents outside of the neighborhood. Nonetheless, they reported higher rates of experiencing most incidents of CV inside the participants' neighborhood. The implications of the results for theory development and future research are discussed.

  20. Rating the "Raters": Legal Exposure of Trustmark Authorities in the Context of Consumer Health Informatics

    PubMed Central

    Terry, Nicolas P

    2000-01-01

    There are three areas of potential legal exposure for an organization such as a trustmark authority involved in ehealth quality rating. First, an ehealth provider may make a complaint about negative or impliedly negative ratings rendered by the ratings body (false negative). Typically, a negative ratings complaint would rely on defamation or product disparagement causes of action. In some cases such complaints could be defended on the basis of absence of malice (US). Second, the rating body might render a positive rating on ehealth data that a third party allegedly relied upon and suffered injury (false positive). While the primary cause of action would be against the ehealth data provider, questions may arise as to possible liability of the trustmark authority. For example, some US liability exposure is possible based on cases involving the potential liability of product warrantors, trade associations and certifiers or endorsers. Third, a ratings body may face public law liability for its own web misfeasance. Several risk management approaches are possible and would not necessarily be mutually exclusive. These approaches will require careful investigation to assess their risk reduction potential and, in some cases, legislation.

  1. Rating the raters: legal exposure of trustmark authorities in the context of consumer health informatics.

    PubMed

    Terry, N P

    2000-01-01

    There are three areas of potential legal exposure for an organization such as a trustmark authority involved in e-health quality rating. First, an e-health provider may make a complaint about negative or impliedly negative ratings rendered by the ratings body (false negative). Typically, a negative ratings complaint would rely on defamation or product disparagement causes of action. In some cases such complaints could be defended on the basis of absence of malice (US). Second, the rating body might render a positive rating on e-health data that a third party allegedly relied upon and suffered injury (false positive). While the primary cause of action would be against the e-health data provider, questions may arise as to the possible liability of the trustmark authority. For example, some US liability exposure is possible based on cases involving the potential liability of product warrantors, trade associations, and certifiers or endorsers. Third, a ratings body may face public law liability for its own web misfeasance. Several risk management approaches are possible and would not necessarily be mutually exclusive. These approaches will require careful investigation to assess their risk reduction potential and, in some cases, the introduction of legislation.

  2. Rating the Raters: Legal Exposure of Trustmark Authorities in the Context of Consumer Health Informatics

    PubMed Central

    2000-01-01

    There are three areas of potential legal exposure for an organization such as a trustmark authority involved in e-health quality rating. First, an e-health provider may make a complaint about negative or impliedly negative ratings rendered by the ratings body (false negative). Typically, a negative ratings complaint would rely on defamation or product disparagement causes of action. In some cases such complaints could be defended on the basis of absence of malice (US). Second, the rating body might render a positive rating on e-health data that a third party allegedly relied upon and suffered injury (false positive). While the primary cause of action would be against the e-health data provider, questions may arise as to the possible liability of the trustmark authority. For example, some US liability exposure is possible based on cases involving the potential liability of product warrantors, trade associations, and certifiers or endorsers. Third, a ratings body may face public law liability for its own web misfeasance. Several risk management approaches are possible and would not necessarily be mutually exclusive. These approaches will require careful investigation to assess their risk reduction potential and, in some cases, the introduction of legislation. PMID:11720941

  3. Video-rate imaging of microcirculation with single-exposure oblique back-illumination microscopy.

    PubMed

    Ford, Tim N; Mertz, Jerome

    2013-06-01

    Oblique back-illumination microscopy (OBM) is a new technique for simultaneous, independent measurements of phase gradients and absorption in thick scattering tissues based on widefield imaging. To date, OBM has been used with sequential camera exposures, which reduces temporal resolution, and can produce motion artifacts in dynamic samples. Here, a variation of OBM that allows single-exposure operation with wavelength multiplexing and image splitting with a Wollaston prism is introduced. Asymmetric anamorphic distortion induced by the prism is characterized and corrected in real time using a graphics-processing unit. To demonstrate the capacity of single-exposure OBM to perform artifact-free imaging of blood flow, video-rate movies of microcirculation in ovo in the chorioallantoic membrane of the developing chick are presented. Imaging is performed with a high-resolution rigid Hopkins lens suitable for endoscopy. PMID:23733023

  4. Video-rate imaging of microcirculation with single-exposure oblique back-illumination microscopy

    NASA Astrophysics Data System (ADS)

    Ford, Tim N.; Mertz, Jerome

    2013-06-01

    Oblique back-illumination microscopy (OBM) is a new technique for simultaneous, independent measurements of phase gradients and absorption in thick scattering tissues based on widefield imaging. To date, OBM has been used with sequential camera exposures, which reduces temporal resolution, and can produce motion artifacts in dynamic samples. Here, a variation of OBM that allows single-exposure operation with wavelength multiplexing and image splitting with a Wollaston prism is introduced. Asymmetric anamorphic distortion induced by the prism is characterized and corrected in real time using a graphics-processing unit. To demonstrate the capacity of single-exposure OBM to perform artifact-free imaging of blood flow, video-rate movies of microcirculation in ovo in the chorioallantoic membrane of the developing chick are presented. Imaging is performed with a high-resolution rigid Hopkins lens suitable for endoscopy.

  5. Video-rate imaging of microcirculation with single-exposure oblique back-illumination microscopy.

    PubMed

    Ford, Tim N; Mertz, Jerome

    2013-06-01

    Oblique back-illumination microscopy (OBM) is a new technique for simultaneous, independent measurements of phase gradients and absorption in thick scattering tissues based on widefield imaging. To date, OBM has been used with sequential camera exposures, which reduces temporal resolution, and can produce motion artifacts in dynamic samples. Here, a variation of OBM that allows single-exposure operation with wavelength multiplexing and image splitting with a Wollaston prism is introduced. Asymmetric anamorphic distortion induced by the prism is characterized and corrected in real time using a graphics-processing unit. To demonstrate the capacity of single-exposure OBM to perform artifact-free imaging of blood flow, video-rate movies of microcirculation in ovo in the chorioallantoic membrane of the developing chick are presented. Imaging is performed with a high-resolution rigid Hopkins lens suitable for endoscopy.

  6. UVB Exposure Does Not Accelerate Rates of Litter Decomposition in a Semiarid Riparian Ecosystem

    NASA Astrophysics Data System (ADS)

    Uselman, S. M.; Snyder, K. A.; Blank, R. R.; Jones, T. J.

    2010-12-01

    Aboveground litter decomposition is controlled mainly by substrate quality and climate factors across terrestrial ecosystems, but photodegradation from exposure to high-intensity ultraviolet-B (UVB) radiation may also be important in arid and semi-arid environments. We investigated the interactive effects of UVB exposure and litter quality on decomposition in a Tamarix-invaded riparian ecosystem during the establishment of an insect biological control agent in northern Nevada. Feeding by the northern tamarisk beetle (Diorhabda carinulata) on Tamarix spp. trees leads to altered leaf litter quality and increased exposure to solar UVB radiation from canopy opening. In addition, we examined the dynamics of litter decomposition of the invasive exotic Lepidium latifolium, because it is well-situated to invade beetle-infested Tamarix sites. Three leaf litter types (natural Tamarix, beetle-affected Tamarix, and L. latifolium) differing in substrate quality were decomposed in litterbags for one year in the field. Litterbags were subjected to one of three treatments: (1) Ambient UVB or (2) Reduced UVB (where UVB was manipulated by using clear plastic films that transmit or block UVB), and (3) No Cover (a control used to test for the effect of using the plastic films, i.e. a cover effect). Results showed a large cover effect on rates of decomposition and nutrient release, and our findings suggested that frequent cycles of freeze-thaw, and possibly rainfall intensity, influenced decomposition at this site. Contrary to our expectations, greater UVB exposure did not result in faster rates of decomposition. Greater UVB exposure resulted in decreased rates of decomposition and P release for the lower quality litter and no change in rates of decomposition and nutrient release for the two higher quality litter types, possibly due to a negative effect of UVB on soil microbes. Among litter types, rates of decomposition and net release of N and P followed this ranking: L. latifolium

  7. Dose-rate effects of ethylene oxide exposure on developmental toxicity.

    PubMed

    Weller, E; Long, N; Smith, A; Williams, P; Ravi, S; Gill, J; Henessey, R; Skornik, W; Brain, J; Kimmel, C; Kimmel, G; Holmes, L; Ryan, L

    1999-08-01

    In risk assessment, evaluating a health effect at a duration of exposure that is untested involves assuming that equivalent multiples of concentration (C) and duration (T) of exposure have the same effect. The limitations of this approach (attributed to F. Haber, Zur Geschichte des Gaskrieges [On the history of gas warfare], in Funf Vortrage aus den Jahren 1920-1923 [Five lectures from the years 1920-1923], 1924, Springer, Berlin, pp. 76-92), have been noted in several studies. The study presented in this paper was designed to specifically look at dose-rate (C x T) effects, and it forms an ideal case study to implement statistical models and to examine the statistical issues in risk assessment. Pregnant female C57BL/6J mice were exposed, on gestational day 7, to ethylene oxide (EtO) via inhalation for 1.5, 3, or 6 h at exposures that result in C x T multiples of 2100 or 2700 ppm-h. EtO was selected because of its short half-life, documented developmental toxicity, and relevance to exposures that occur in occupational settings. Concurrent experiments were run with animals exposed to air for similar periods. Statistical analysis using models developed to assess dose-rate effects revealed significant effects with respect to fetal death and resorptions, malformations, crown-to-rump length, and fetal weight. Animals exposed to short, high exposures of EtO on day 7 of gestation were found to have more adverse effects than animals exposed to the same C x T multiple but at longer, lower exposures. The implication for risk assessment is that applying Haber's Law could potentially lead to an underestimation of risk at a shorter duration of exposure and an overestimation of risk at a longer duration of exposure. Further research, toxicological and statistical, are required to understand the mechanism of the dose-rate effects, and how to incorporate the mechanistic information into the risk assessment decision process. PMID:10478863

  8. Important Physiological Parameters and Physical Activity Data for Evaluating Exposure Modeling Performance: a Synthesis

    EPA Science Inventory

    The purpose of this report is to develop a database of physiological parameters needed for understanding and evaluating performance of the APEX and SHEDS exposure/intake dose rate model used by the Environmental Protection Agency (EPA) as part of its regulatory activities. The A...

  9. Osteoblast fibronectin mRNA, protein synthesis, and matrix are unchanged after exposure to microgravity

    NASA Technical Reports Server (NTRS)

    Hughes-Fulford, M.; Gilbertson, V.

    1999-01-01

    The well-defined osteoblast line, MC3T3-E1 was used to examine fibronectin (FN) mRNA levels, protein synthesis, and extracellular FN matrix accumulation after growth activation in spaceflight. These osteoblasts produce FN extracellular matrix (ECM) known to regulate adhesion, differentiation, and function in adherent cells. Changes in bone ECM and osteoblast cell shape occur in spaceflight. To determine whether altered FN matrix is a factor in causing these changes in spaceflight, quiescent osteoblasts were launched into microgravity and were then sera activated with and without a 1-gravity field. Synthesis of FN mRNA, protein, and matrix were measured after activation in microgravity. FN mRNA synthesis is significantly reduced in microgravity (0-G) when compared to ground (GR) osteoblasts flown in a centrifuge simulating earth's gravity (1-G) field 2.5 h after activation. However, 27.5 h after activation there were no significant differences in mRNA synthesis. A small but significant reduction of FN protein was found in the 0-G samples 2.5 h after activation. Total FN protein 27.5 h after activation showed no significant difference between any of the gravity conditions, however, there was a fourfold increase in absolute amount of protein synthesized during the incubation. Using immunofluorescence, we found no significant differences in the amount or in the orientation of the FN matrix after 27.5 h in microgravity. These results demonstrate that FN is made by sera-activated osteoblasts even during exposure to microgravity. These data also suggest that after a total period of 43 h of spaceflight FN transcription, translation, or altered matrix assembly is not responsible for the altered cell shape or altered matrix formation of osteoblasts.

  10. Mortality rates in a female cohort following asbestos exposure in Germany.

    PubMed

    Rösler, J A; Woitowitz, H J; Lange, H J; Woitowitz, R H; Ulm, K; Rödelsperger, K

    1994-08-01

    A cohort study was conducted of 616 German female workers with a history of exposure to asbestos. Standardized proportionate mortality analysis was done except for mesothelioma, for which proportionate mortality was computed based on best evident cause of death. Mortality from lung cancer was increased three times over expected value. Death rates due to mesothelioma were 340 times higher than in the general population. Female mortality rates surpassed those observed in men twofold for lung cancer and fourfold for mesothelioma. In comparison with published data from international cohort studies, the observed mortality for mesothelioma in our female cohort appeared higher than that previously reported. German women with a history of asbestos exposure are considered a high-risk group for developing mesothelioma and lung cancer. They should be a target group for intervention strategies (eg, chemoprevention, smoking cessation, early cancer detection).

  11. Addressing the recovery of feeding rates in post-exposure feeding bioassays: Cyathura carinata as a case study

    SciTech Connect

    Pais-Costa, Antonia Juliana; Acevedo, Pelayo; Marques, João Carlos; Martinez-Haro, Mónica

    2015-02-15

    Post-exposure bioassays are used in environmental assessment as a cost-effective tool, but the effects of organism's recovery after exposure to pollutant has not yet been addressed in detail. The recoveries of post-exposure feeding rates after being exposed to two sublethal concentrations of cadmium during two different exposure periods (48 h and 96 h) were evaluated under laboratory conditions using the estuarine isopod Cyathura carinata. Results showed that feeding depression was a stable endpoint up to 24 h after cadmium exposure, which is useful for ecotoxicological bioassays. - Highlights: • We studied recovery of post-exposure feeding rates 48–96 h after cadmium exposure. • The assay is based on the isopod Cyathura carinata. • Post-exposure feeding inhibition is a stable sublethal endpoint.

  12. Contact rates and exposure to inter-species disease transmission in mountain ungulates.

    PubMed

    Richomme, C; Gauthier, D; Fromont, E

    2006-02-01

    The risk for a pathogen to cross the species barrier depends on the rate of efficient contacts between the species. However, contact rates between species have rarely been estimated from observations. Here we estimate contact rates and exposure of chamois Rupicapra rupicapra and Alpine ibex Capra ibex exposed to domestic pasteurellosis and brucellosis carried by sheep or cattle herds summering in mountain pastures. We use field observation data on animal positions treated in a geographic information system (GIS). Comparing 10 pastures, we show that the management of domestic herds influences the risk of inter-species transmission. Exposure to direct transmission of pasteurellosis is high when herds are not guarded nor enclosed, whereas exposure to indirect transmission of brucellosis is increased on epidemiological dangerous points such as salt deposits. Our preliminary results need further investigation, but they underline the importance of both herd management and pathogen transmission mode when the aim is to reduce the risk of contamination of wild populations by a pathogen associated with domestic pathogens.

  13. In vivo measurement of DNA synthesis rates of colon epithelial cells in carcinogenesis

    SciTech Connect

    Kim, Sylvia Jeewon; Turner, Scott; Killion, Salena; Hellerstein, Marc K. . E-mail: march@nature.berkeley.edu

    2005-05-27

    We describe here a highly sensitive technique for measuring DNA synthesis rates of colon epithelial cells in vivo. Male SD rats were given {sup 2}H{sub 2}O (heavy water). Colon epithelial cells were isolated, DNA was extracted, hydrolyzed to deoxyribonucleosides, and the deuterium enrichment of the deoxyribose moiety was determined by gas chromatographic/mass spectrometry. Turnover time of colon crypts and the time for migration of cells from basal to top fraction of the crypts were measured. These data were consistent with cell cycle analysis and bromodeoxyuridine labeling. By giving different concentrations of a promoter, dose-dependent increases in DNA synthesis rates were detected, demonstrating the sensitivity of the method. Administration of a carcinogen increased DNA synthesis rates cell proliferation in all fractions of the crypt. In conclusion, DNA synthesis rates of colon epithelial cells can be measured directly in vivo using stable-isotope labeling. Potential applications in humans include use as a biomarker for cancer chemoprevention studies.

  14. Effect of frequency of dosing of plant sterols on plasma cholesterol levels and synthesis rate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective was to compare the effects of plant sterols (PS) consumed as a single dose (single) at breakfast or as three doses consumed with breakfast, lunch and dinner (divided) on plasma lipoprotien levels and cholesterol endogenous fractional synthesis rate (FSR). A randomized, placebo-controll...

  15. Protein synthesis rates in rat brain regions and subcellular fractions during aging

    SciTech Connect

    Avola, R.; Condorelli, D.F.; Ragusa, N.; Renis, M.; Alberghina, M.; Giuffrida Stella, A.M.; Lajtha, A.

    1988-04-01

    In vivo protein synthesis rates in various brain regions (cerebral cortex, cerebellum, hippocampus, hypothalamus, and striatum) of 4-, 12-, and 24-month-old rats were examined after injection of a flooding dose of labeled valine. The incorporation of labeled valine into proteins of mitochondrial, microsomal, and cytosolic fractions from cerebral cortex and cerebellum was also measured. At all ages examined, the incorporation rate was 0.5% per hour in cerebral cortex, cerebellum, hippocampus, and hypothalamus and 0.4% per hour in striatum. Of the subcellular fractions examined, the microsomal proteins were synthesized at the highest rate, followed by cytosolic and mitochondrial proteins. The results obtained indicate that the average synthesis rate of proteins in the various brain regions and subcellular fractions examined is fairly constant and is not significantly altered in the 4 to 24-month period of life of rats.

  16. Effects of HMX exposure upon metabolic rate of northern bobwhite quail (Colinus virginianus) in ovo.

    PubMed

    Liu, Jun; Cox, Stephen B; Beall, Blake; Brunjes, Kristina J; Pan, Xiaoping; Kendall, Ronald J; Anderson, Todd A; McMurry, Scott T; Cobb, George P; Smith, Philip N

    2008-05-01

    We evaluated the use of the gas exchange rate as an ecologically relevant indicator of chemical stress in avian embryos/eggs. Northern bobwhite quail (Colinus virginianus) were exposed to octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) via feed containing nominal concentrations of 0, 12.5, 50.0, and 125.0 mg kg(-1). Metabolic rates (oxygen consumption) of developing quail eggs were then measured via respirometry to examine potential effects of HMX exposure. Metabolic rates were examined on 5, 9, and 21 d of incubation. Next, concentrations of HMX in embryos/eggs were determined by liquid chromatography-mass spectrometry. Mean (+/-SE) concentrations of HMX in eggs were 21.0+/-5.9, 1113+/-79.0, 3864+/-154.0, and 7426+/-301.1 ng g(-1) in control, low, medium and high dose groups, respectively. There were significant differences in oxygen consumption among the three embryo ages, however differences among the ages were not consistent among dose groups (age x dose group interaction p<0.0001). Oxygen consumption rates did not vary as a function of HMX in embryos (p=0.18). No evidence was observed for alterations of in ovo metabolic rates associated with HMX exposure.

  17. Importance of amino acid composition to improve skin collagen protein synthesis rates in UV-irradiated mice.

    PubMed

    Murakami, Hitoshi; Shimbo, Kazutaka; Inoue, Yoshiko; Takino, Yoshinobu; Kobayashi, Hisamine

    2012-06-01

    Skin collagen metabolism abnormalities induced by ultraviolet (UV) radiation are the major causes of skin photoaging. It has been shown that the one-time exposure of UV irradiation decreases procollagen mRNA expression in dermis and that chronic UV irradiation decreases collagen amounts and induces wrinkle formation. Amino acids are generally known to regulate protein metabolism. Therefore, we investigated the effects of UV irradiation and various orally administered amino acids on skin collagen synthesis rates. Groups of 4-5 male, 8-week-old HR-1 hairless mice were irradiated with UVB (66 mJ/cm2) twice every other day, then fasted for 16 h. The fractional synthesis rate (FSR; %/h) of skin tropocollagen was evaluated by incorporating L-[ring-2H5]-phenylalanine. We confirmed that the FSR of dermal tropocollagen decreased after UVB irradiation. The FSR of dermal tropocollagen was measured 30 min after a single oral administration of amino acids (1 g/kg) to groups of 5-16 UVB-irradiated mice. Branched-chain amino acids (BCAA, 1.34±0.32), arginine (Arg, 1.66±0.39), glutamine (Gln, 1.75±0.60), and proline (Pro, 1.48±0.26) did not increase the FSR of skin tropocollagen compared with distilled water, which was used as a control (1.56±0.30). However, essential amino acids mixtures (BCAA+Arg+Gln, BCAA+Gln, and BCAA+Pro) significantly increased the FSR (2.07±0.58, 2.04±0.54, 2.01±0.50 and 2.07±0.59, respectively). This result suggests that combinations of BCAA and glutamine or proline are important for restoring dermal collagen protein synthesis impaired by UV irradiation.

  18. Exposure to Discrimination and Heart Rate Variability Reactivity to Acute Stress among Women with Diabetes.

    PubMed

    Wagner, Julie; Lampert, Rachel; Tennen, Howard; Feinn, Richard

    2015-08-01

    Exposure to racial discrimination has been linked to physiological reactivity. This study investigated self-reported exposure to racial discrimination and parasympathetic [high-frequency heart rate variability (HF-HRV)] and sympathetic (norepinephrine and cortisol) activity at baseline and then again after acute laboratory stress. Lifetime exposure to racial discrimination was measured with the Schedule of Racist Events scale. Thirty-two women (16 Black and 16 White) with type 2 diabetes performed a public speaking stressor. Beat-to-beat intervals were recorded on electrocardiograph recorders, and HF-HRV was calculated using spectral analysis and natural log transformed. Norepinephrine and cortisol were measured in blood. Higher discrimination predicted lower stressor HF-HRV, even after controlling for baseline HF-HRV. When race, age, A1c and baseline systolic blood pressure were also controlled, racial discrimination remained a significant independent predictor of stressor HF-HRV. There was no association between lifetime discrimination and sympathetic markers. In conclusion, preliminary data suggest that among women with type 2 diabetes mellitus (T2DM), exposure to racial discrimination is adversely associated with parasympathetic, but not sympathetic, reactivity.

  19. Night Heart Rate Variability and Particulate Exposures among Boilermaker Construction Workers

    PubMed Central

    Cavallari, Jennifer M.; Eisen, Ellen A.; Chen, Jiu-Chiuan; Fang, Shona C.; Dobson, Christine B.; Schwartz, Joel; Christiani, David C.

    2007-01-01

    Background Although studies have documented the association between heart rate variability (HRV) and ambient particulate exposures, the association between HRV, especially at night, and metal-rich, occupational particulate exposures remains unclear. Objective Our goal in this study was to investigate the association between long-duration HRV, including nighttime HRV, and occupational PM2.5 exposures. Methods We used 24-hr ambulatory electrocardiograms (ECGs) to monitor 36 male boilermaker welders (mean age of 41 years) over a workday and nonworkday. ECGs were analyzed for HRV in the time domain; rMSSD (square root of the mean squared differences of successive intervals), SDNN (SD of normal-to-normal intervals over entire recording), and SDNNi (SDNN for all 5-min segments) were summarized over 24-hr, day (0730–2130 hours), and night (0000–0700 hours) periods. PM2.5 (particulate matter with an aerodynamic diameter ≤ 2.5 μm) exposures were monitored over the workday, and 8-hr time-weighted average concentrations were calculated. We used linear regression to assess the associations between HRV and workday particulate exposures. Matched measurements from a nonworkday were used to control for individual cardiac risk factors. Results Mean (± SD) PM2.5 exposure was 0.73 ± 0.50 mg/m3 and ranged from 0.04 to 2.70 mg/m3. We observed a consistent inverse exposure–response relationship, with a decrease in all HRV measures with increased PM2.5 exposure. However, the decrease was most pronounced at night, where a 1-mg/m3 increase in PM2.5 was associated with a change of −8.32 [95% confidence interval (CI), −16.29 to −0.35] msec nighttime rMSSD, −14.77 (95% CI, −31.52 to 1.97) msec nighttime SDNN, and −8.37 (95% CI, −17.93 to 1.20) msec nighttime SDNNi, after adjusting for nonworking nighttime HRV, age, and smoking. Conclusion Metal-rich particulate exposures were associated with decreased long-duration HRV, especially at night. Further research is needed

  20. Mortality rates in the Federal Republic of Germany following previous occupational exposure to asbestos dust.

    PubMed

    Woitowitz, H J; Lange, H J; Beierl, L; Rathgeb, M; Schmidt, K; Ulm, K; Giesen, T; Woitowitz, R H; Pache, L; Rödelsperger, K

    1986-01-01

    In 1972, a procedure was introduced by the Industrial Injuries Insurance Institutes (Berufsgenossenschaften) of the Federal Republic of Germany, which is to be used by the special occupational health service for employees exposed to asbestos dust. Since 1 January 1972, occupational health examinations are performed when exposure to asbestos dust has been of at least 3 years' duration. On 1 January 1977, a prospective cohort study was started with employees formerly exposed to asbestos dust whilst working for companies manufacturing or using asbestos. Data on these persons are collected in the Central Register of Employees Exposed to Asbestos Dust of the Industrial Injuries Insurance Institutes. A total of 3,070 male and female employees in whom asbestos exposure terminated after 1 January 1972 formed subcohort I of the study. For comparison, 665 persons whose exposure terminated before 1 January 1972 served as subcohort II. In addition to several other inclusion criteria, each individual's permission was required before personal data could be evaluated. Of the subjects in the two subcohorts, 185 and 71, respectively, had died by 31 December 1982. Tumours were more frequently than this cause of death is expected in the general population. In addition to a high incidence of mesothelioma, the standard mortality rate was especially increased for lung cancer. The proportional mortality rates of about 40% for tumours of all sites (with about 17% lung cancer and 8% mesothelioma) especially in subcohort II, seemed to be comparable to the international figures for epidemiological mortality.

  1. Effect of cabin ventilation rate on ultrafine particle exposure inside automobiles.

    PubMed

    Knibbs, Luke D; de Dear, Richard J; Morawska, Lidia

    2010-05-01

    We alternately measured on-road and in-vehicle ultrafine (<100 nm) particle (UFP) concentration for 5 passenger vehicles that comprised an age range of 18 years. A range of cabin ventilation settings were assessed during 301 trips through a 4 km road tunnel in Sydney, Australia. Outdoor air flow (ventilation) rates under these settings were quantified on open roads using tracer gas techniques. Significant variability in tunnel trip average median in-cabin/on-road (I/O) UFP ratios was observed (0.08 to approximately 1.0). Based on data spanning all test automobiles and ventilation settings, a positive linear relationship was found between outdoor air flow rate and I/O ratio, with the former accounting for a substantial proportion of variation in the latter (R(2) = 0.81). UFP concentrations recorded in-cabin during tunnel travel were significantly higher than those reported by comparable studies performed on open roadways. A simple mathematical model afforded the ability to predict tunnel trip average in-cabin UFP concentrations with good accuracy. Our data indicate that under certain conditions, in-cabin UFP exposures incurred during tunnel travel may contribute significantly to daily exposure. The UFP exposure of automobile occupants appears strongly related to their choice of ventilation setting and vehicle. PMID:20369882

  2. 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. PMID:26469570

  3. 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.

  4. Agricultural adjuvants: acute mortality and effects on population growth rate of Daphnia pulex after chronic exposure.

    PubMed

    Stark, John D; Walthall, William K

    2003-12-01

    Acute and chronic toxicity of eight agricultural adjuvants (Bond, Kinetic, Plyac, R-11, Silwet L-77, Sylgard 309, X-77, and WaterMaxx) to Daphnia pulex were evaluated with 48-h acute lethal concentration estimates (LC50) and a 10-d population growth-rate measurement, the instantaneous rate of increase (r1). Based on LC50, the order of toxicity was R-11 > X-77 = Sylgard 309 = Silwet L-77 > Kinetic > Bond > Plyac > WaterMaxx; all LC50 estimates were higher than the expected environmental concentration (EEC) of 0.79 mg/L, indicating that none of these adjuvants should cause high levels of mortality in wild D. pulex populations. Extinction, defined as negative population growth rate, occurred after exposure to 0.9 mg/L R-11, 13 mg/L X-77, 25 mg/L Kinetic, 28 mg/L Silwet, 18 mg/L Sylgard, 450 mg/L Bond, 610 mg/L Plyac, and 1,600 mg/L WaterMaxx. Concentrations that caused extinction were substantially below the acute LC50 for R-11, Kinetic, Plyac, X-77, and Bond. The no-observable-effects concentration (NOEC) and lowest-observable-effects concentration (LOEC) for the number of offspring per surviving female after exposure to R-11 were 0.5 and 0.75 mg/L, respectively. The NOEC and LOEC for population size after exposure to R-11 were (1.25 and 0.5 mg/L, respectively. Both of these values were lower than the EEC, indicating that R-11 does have the potential to cause damage to D. pulex populations after application at recommended field rates. The wide range of concentrations causing extinction makes it difficult to generalize about the potential impacts that agricultural adjuvants might have on aquatic ecosystems. Therefore, additional studies that examine effects on other nontarget organisms and determine residues in aquatic ecosystems may be warranted.

  5. Recharge Rates and Chemistry Beneath Playas of the High Plains Aquifer - A Literature Review and Synthesis

    USGS Publications Warehouse

    Gurdak, Jason J.; Roe, Cassia D.

    2009-01-01

    Playas are ephemeral, closed-basin wetlands that are important zones of recharge to the High Plains (or Ogallala) aquifer and critical habitat for birds and other wildlife in the otherwise semiarid, shortgrass prairie and agricultural landscape. The ephemeral nature of playas, low regional recharge rates, and a strong reliance on ground water from the High Plains aquifer has prompted many questions regarding the contribution of recharge from playas to the regional aquifer. To address these questions and concerns, the U.S. Geological Survey, in cooperation with the Playa Lakes Joint Venture, present a review and synthesis of the more than 175 publications about recharge rates and chemistry beneath playas and interplaya settings. Although a number of questions remain regarding the controls on recharge rates and chemistry beneath playas, the results from most published studies indicate that recharge rates beneath playas are substantially (1 to 2 orders of magnitude) higher than recharge rates beneath interplaya settings. The synthesis presented here supports the conceptual model that playas are important zones of recharge to the High Plains aquifer and are not strictly evaporative pans. The major findings of this synthesis yield science-based implications for the protection and management of playas and ground-water resources of the High Plains aquifer and directions for future research.

  6. Dose-rate models for human survival after exposure to ionizing radiation

    SciTech Connect

    Jones, T.D.; Morris, M.D.; Young, R.W.

    1986-01-01

    This paper reviews new estimates of the L/sub 50/ in man by Mole and by Rotblat, the biological processes contributing to hematologic death, the collection of animal experiments dealing with hematologic death, and the use of regression analysis to make new estimates of human mortality based on all relevant animal studies. Regression analysis of animal mortality data has shown that mortality is dependent strongly on dose rate, species, body weight, and time interval over which the exposure is delivered. The model has predicted human LD/sub 50/s of 194, 250, 310, and 360 rad to marrow when the exposure time is a minute, an hour, a day, and a week, respectively.

  7. Measurement of air exchange rate of stationary vehicles and estimation of in-vehicle exposure.

    PubMed

    Park, J H; Spengler, J D; Yoon, D W; Dumyahn, T; Lee, K; Ozkaynak, H

    1998-01-01

    The air exchange rates or air changes per hour (ACH) were measured under 4 conditions in 3 stationary automobiles. The ACH ranged between 1.0 and 3.0 h-1 with windows closed and no mechanical ventilation, between 1.8 and 3.7 h-1 for windows closed with fan set on recirculation, between 13.3 and 26.1 h-1 for window open with no mechanical ventilation, and between 36.2 and 47.5 h-1 for window closed with the fan set on fresh air. ACHs for windows closed with no ventilation were higher for the older automobile than for the newer automobiles. With the windows closed and fan turned off, ACH was not influenced by wind speed (p > 0.05). When the window was open, ACH appeared to be greatly affected by wind speed (R2 = 0.86). These measurements are relevant to understanding exposures inside automobiles to sources such as dry-cleaned clothes, cigarettes and airbags. Therefore, to understand the in-vehicle exposure to these internal sources, perchloroethylene (PCE) emitted from dry-cleaned clothes and environmental tobacco smoke (ETS) inside a vehicle were modeled for simulated driving cycles. Airbag deployment was also modeled for estimating exposure level to alkaline particulate and carbon monoxide (CO). Average exposure to PCE inside a vehicle for 30 minutes period was high (approximately 780 micrograms/m3); however, this is only 6% of the two-week exposure that is influenced by the storage of dry cleaned clothing at home. On the other hand, the exposure levels of respirable suspended particulate (RSP) and formaldehyde due to ETS could reach 2.1 mg/m3 and 0.11 ppm, respectively, when a person smokes inside a driving car even with the window open. In modeling the in-vehicle concentrations following airbag deployment, the average CO level over 20 minutes would not appear to present problem (less than 28 ppm). The peak concentration of respirable particulate would have exceeded 140 mg/m3. Since most of the particle mass is composed of alkaline material, these high levels

  8. Paint thinner exposure inhibits testosterone synthesis and secretion in a reversible manner in the rat.

    PubMed

    Yilmaz, Bayram; Canpolat, Sinan; Sandal, Suleyman; Akpolat, Nusret; Kutlu, Selim; Ilhan, Necip; Kelestimur, Haluk

    2006-11-01

    Occupational exposure and sniffing of toluene-based organic solvents is an important public health problem. In this study, we have investigated the effects of paint thinner inhalation on testosterone synthesis and secretion in the male rat. A control group inhaled normal air ventilation. The remaining animals were divided into three groups and exposed to paint thinner in a glassy cage for 15 and 30 days (2 h/day). A group of rats was allowed to recover for 15 days after 30 days of exposure. Toluene concentration (the largest constituent in thinner, 66%) was set at 1500 ppm in the inhaled air. At the end, all animals were decapitated and blood samples obtained. Testes and seminal vesicles were removed and weighed out. Serum total testosterone levels were determined by chemiluminescence enzyme immunoassay. Testicular tissue specimens were processed for semi-quantitative evaluation of immunohistochemical testosterone staining and light microscopy. Intensity of immunostaining was evaluated on a scale between 0 (no staining), 1 (minimal), 2 (mild), 3 (moderate) and 4 (strong staining). Serum testosterone levels (ng/ml) were decreased by 15-day (3.31+/-0.61) and 30-day (1.17+/-0.54, p<0.02) thinner exposure compared to the controls (3.91+/-1.03). Another group of rats exposed to thinner for 30 days and then allowed to recover for a period of 15 days had significantly elevated levels of testosterone values (3.77+/-1.1; p<0.05). Immunohistochemical testosterone staining of the cytoplasm of Leydig cells was moderate (3+) and mild (2+) in 15 and 30 days thinner inhalation groups, respectively. Strong staining (4+) was restored following the recovery period. Testicular weight was significantly reduced in all test groups compared to the control values (p<0.01). Diameters of seminiferous tubules were significantly decreased in the solvent exposed groups with enlarged connective tissue. The present findings suggest that paint thinner inhalation inhibits testosterone synthesis

  9. Serotonin synthesis rate and the tryptophan hydroxylase-2: G-703T polymorphism in social anxiety disorder.

    PubMed

    Furmark, Tomas; Marteinsdottir, Ina; Frick, Andreas; Heurling, Kerstin; Tillfors, Maria; Appel, Lieuwe; Antoni, Gunnar; Hartvig, Per; Fischer, Håkan; Långström, Bengt; Eriksson, Elias; Fredrikson, Mats

    2016-10-01

    It is disputed whether anxiety disorders, like social anxiety disorder, are characterized by serotonin over- or underactivity. Here, we evaluated whether our recent finding of elevated neural serotonin synthesis rate in patients with social anxiety disorder could be reproduced in a separate cohort, and whether allelic variation in the tryptophan hydroxylase-2 (TPH2) G-703T polymorphism relates to differences in serotonin synthesis assessed with positron emission tomography. Eighteen social anxiety disorder patients and six healthy controls were scanned during 60 minutes in a resting state using positron emission tomography and 5-hydroxy-L-[β -(11)C]tryptophan, [(11)C]5-HTP, a substrate of the second enzymatic step in serotonin synthesis. Parametric images were generated, using the reference Patlak method, and analysed using Statistical Parametric Mapping (SPM8). Blood samples for genotyping of the TPH2 G-703T polymorphism were obtained from 16 social anxiety disorder patients (T carriers: n=5, GG carriers: n=11). A significantly elevated [(11)C]5-HTP accumulation rate, indicative of enhanced decarboxylase activity and thereby serotonin synthesis capacity, was detected in social anxiety disorder patients compared with controls in the hippocampus and basal ganglia nuclei and, at a more lenient (uncorrected) statistical threshold, in the amygdala and anterior cingulate cortex. In patients, the serotonin synthesis rate in the amygdala and anterior cingulate cortex was significantly elevated in TPH2 T carriers in comparison with GG homozygotes. Our results support that social anxiety disorder entails an overactive presynaptic serotonergic system that, in turn, seems functionally influenced by the TPH2 G-703T polymorphism in emotionally relevant brain regions.

  10. Serotonin synthesis rate and the tryptophan hydroxylase-2: G-703T polymorphism in social anxiety disorder.

    PubMed

    Furmark, Tomas; Marteinsdottir, Ina; Frick, Andreas; Heurling, Kerstin; Tillfors, Maria; Appel, Lieuwe; Antoni, Gunnar; Hartvig, Per; Fischer, Håkan; Långström, Bengt; Eriksson, Elias; Fredrikson, Mats

    2016-10-01

    It is disputed whether anxiety disorders, like social anxiety disorder, are characterized by serotonin over- or underactivity. Here, we evaluated whether our recent finding of elevated neural serotonin synthesis rate in patients with social anxiety disorder could be reproduced in a separate cohort, and whether allelic variation in the tryptophan hydroxylase-2 (TPH2) G-703T polymorphism relates to differences in serotonin synthesis assessed with positron emission tomography. Eighteen social anxiety disorder patients and six healthy controls were scanned during 60 minutes in a resting state using positron emission tomography and 5-hydroxy-L-[β -(11)C]tryptophan, [(11)C]5-HTP, a substrate of the second enzymatic step in serotonin synthesis. Parametric images were generated, using the reference Patlak method, and analysed using Statistical Parametric Mapping (SPM8). Blood samples for genotyping of the TPH2 G-703T polymorphism were obtained from 16 social anxiety disorder patients (T carriers: n=5, GG carriers: n=11). A significantly elevated [(11)C]5-HTP accumulation rate, indicative of enhanced decarboxylase activity and thereby serotonin synthesis capacity, was detected in social anxiety disorder patients compared with controls in the hippocampus and basal ganglia nuclei and, at a more lenient (uncorrected) statistical threshold, in the amygdala and anterior cingulate cortex. In patients, the serotonin synthesis rate in the amygdala and anterior cingulate cortex was significantly elevated in TPH2 T carriers in comparison with GG homozygotes. Our results support that social anxiety disorder entails an overactive presynaptic serotonergic system that, in turn, seems functionally influenced by the TPH2 G-703T polymorphism in emotionally relevant brain regions. PMID:27189957

  11. Optimization of synthesis and peptization steps to obtain iron oxide nanoparticles with high energy dissipation rates

    NASA Astrophysics Data System (ADS)

    Mérida, Fernando; Chiu-Lam, Andreina; Bohórquez, Ana C.; Maldonado-Camargo, Lorena; Pérez, María-Eglée; Pericchi, Luis; Torres-Lugo, Madeline; Rinaldi, Carlos

    2015-11-01

    Magnetic Fluid Hyperthermia (MFH) uses heat generated by magnetic nanoparticles exposed to alternating magnetic fields to cause a temperature increase in tumors to the hyperthermia range (43-47 °C), inducing apoptotic cancer cell death. As with all cancer nanomedicines, one of the most significant challenges with MFH is achieving high nanoparticle accumulation at the tumor site. This motivates development of synthesis strategies that maximize the rate of energy dissipation of iron oxide magnetic nanoparticles, preferable due to their intrinsic biocompatibility. This has led to development of synthesis strategies that, although attractive from the point of view of chemical elegance, may not be suitable for scale-up to quantities necessary for clinical use. On the other hand, to date the aqueous co-precipitation synthesis, which readily yields gram quantities of nanoparticles, has only been reported to yield sufficiently high specific absorption rates after laborious size selective fractionation. This work focuses on improvements to the aqueous co-precipitation of iron oxide nanoparticles to increase the specific absorption rate (SAR), by optimizing synthesis conditions and the subsequent peptization step. Heating efficiencies up to 1048 W/gFe (36.5 kA/m, 341 kHz; ILP=2.3 nH m2 kg-1) were obtained, which represent one of the highest values reported for iron oxide particles synthesized by co-precipitation without size-selective fractionation. Furthermore, particles reached SAR values of up to 719 W/gFe (36.5 kA/m, 341 kHz; ILP=1.6 nH m2 kg-1) when in a solid matrix, demonstrating they were capable of significant rates of energy dissipation even when restricted from physical rotation. Reduction in energy dissipation rate due to immobilization has been identified as an obstacle to clinical translation of MFH. Hence, particles obtained with the conditions reported here have great potential for application in nanoscale thermal cancer therapy.

  12. Multiple contexts of exposure: Activity spaces, residential neighborhoods, and self-rated health.

    PubMed

    Sharp, Gregory; Denney, Justin T; Kimbro, Rachel T

    2015-12-01

    Although health researchers have made progress in detecting place effects on health, existing work has largely focused on the local residential neighborhood and has lacked a temporal dimension. Little research has integrated both time and space to understand how exposure to multiple contexts - where adults live, work, shop, worship, and seek healthcare - influence and shape health and well-being. This study uses novel longitudinal data from the Los Angeles Family and Neighborhood Survey to delve deeper into the relationship between context and health by considering residential and activity space neighborhoods weighted by the amount of time spent in these contexts. Results from multilevel cross-classified logistic models indicate that contextual exposure to disadvantage, residential or non-residential, is independently associated with a higher likelihood of reporting poor or fair health. We also find support for a contextual incongruence hypothesis. For example, adults living in the most disadvantaged neighborhoods are more likely to report poor or fair health when they spend time in more advantaged neighborhoods than in more disadvantaged ones, while residents of more advantaged neighborhoods report worse health when they spend time in more disadvantaged areas. Our results suggest that certain types of place-based cumulative exposures are associated with a sense of relative neighborhood deprivation that potentially manifests in worse health ratings.

  13. Chemical exposure of embryos during the preimplantation stages of pregnancy: mortality rate and intrauterine development.

    PubMed

    Fabro, S; McLachlan, J A; Dames, N M

    1984-04-01

    Exposure of CD-1 mouse embryos at the eight- to 16-cell stage for 1 hour to methylmethanesulfonate (MMS; 0.25, 0.5, and 1.0 mM) produced DNA breakage and interfered with embryonic development in a dose-related manner. MMS-exposed blastocysts were transferred to oviducts of untreated recipient female mice, and the conceptuses were allowed to develop to term. MMS exposure resulted in an increased intrauterine death rate, although the number of implantation sites was not decreased. Surviving MMS-treated offspring showed intrauterine growth retardation, but there was no increase in the incidence of gross abnormalities. Intrauterine growth retardation, without an increase in gross abnormalities, was also observed in the offspring of pregnant New Zealand White rabbits dosed during the preimplantation stages of pregnancy with an "environmental cocktail" composed of ethanol, nicotine, caffeine, sodium salicylate, and dichloro-diphenyl-trichloro-ethane (DDT). When the compounds were tested individually, nicotine and DDT were the only two that produced intrauterine growth retardation. DDT-treated 8-day rabbit conceptuses were smaller than controls and showed abnormal persistence of preimplantation proteins in the yolk sac fluid. These results suggest that exposure to chemicals during the preimplantation stages of pregnancy may result in a cessation of growth and development before implantation or during later intrauterine development. Damage can be repaired but it may result in offspring that show intrauterine growth retardation without gross abnormalities. PMID:6711631

  14. Direct vs. indirect pathway of hepatic glycogen synthesis as a function of glucose infusion rate

    SciTech Connect

    Bagby, G.J.; Lang, C.H.; Johnson, J.L.; Blakesly, H.L.; Spitzer, J.J.

    1986-03-05

    This study was initiated to determine the influence of the rate of exogenous glucose administration on liver glycogen synthesis by the direct (glucose uptake and incorporation into glycogen) vs the indirect pathway (glucose degradation to 3-carbon intermediates, e.g., lactate, prior to incorporation into glycogen). Catheterized rats were fasted 2 days prior to receiving a 3 hr infusion of glucose at rates of 0 to 230 ..mu..mol/min/kg containing tracer (6-/sup 3/H)- and (U-/sup 14/C)-glucose. Plasma glucose (r = 0.80), insulin (r = 0.90) and lactate (r = 0.84) were correlated with glucose infusion rate. The rate of liver glycogen deposition (0.46 +/- 0.03 ..mu..mol/min/g) did not differ between a glucose infusion rate of 20 and 230 ..mu..mol/min/kg. At the lowest and highest glucose infusion rates hepatic glycogenesis accounted for 87 +/- 6 and 9 +/- 1% of the total glucose load, respectively. The percent contribution of the direct pathways to glycogen deposition ((/sup 3/H) specific activity in hepatic glycogen/(/sup 3/H) specific activity in plasma glucose) increased from 16 +/- 3 to 83 +/- 5% from lowest to highest glucose infusion rates (prevailing plasma glucose concentrations: 9 +/- 1 and 21 +/- 2 mM, respectively). The results indicate that the relative contribution of the direct and indirect pathways of glucogen synthesis are dependent upon the glucose load or plasma glucose concentration.

  15. Investigation of exposure rates and radionuclide and trace metal distributions along the Hanford Reach of the Columbia River

    SciTech Connect

    Cooper, A.T.; Woodruff, R.K.

    1993-09-01

    Studies have been conducted to investigate exposure rates, and radionuclide and trace metal distributions along the Columbia River where it borders the Hanford Site. The last major field study was conducted in 1979. With recently renewed interest in various land use and resource protection alternatives, it is important to have data that represent current conditions. Radionuclides and trace metals were surveyed in Columbia River shoreline soils along the Hanford Site (Hanford Reach). The work was conducted as part of the Surface Environmental Surveillance Project, Pacific Northwest Laboratory. The survey consisted of taking exposure rate measurements and soil samples primarily at locations known or expected to have elevated exposure rates.

  16. Personal Exposure to Household Particulate Matter, Household Activities and Heart Rate Variability among Housewives

    PubMed Central

    Huang, Ya-Li; Chen, Hua-Wei; Han, Bor-Cheng; Liu, Chien-Wei; Chuang, Hsiao-Chi; Lin, Lian-Yu; Chuang, Kai-Jen

    2014-01-01

    Background The association between indoor air pollution and heart rate variability (HRV) has been well-documented. Little is known about effects of household activities on indoor air quality and HRV alteration. To investigate changes in HRV associated with changes in personal exposure to household particulate matter (PM) and household activities. Methods We performed 24-h continuous monitoring of electrocardiography and measured household PM exposure among 50 housewives. The outcome variables were log10-transformed standard deviation of normal-to-normal (NN) intervals (SDNN) and the square root of the mean of the sum of the squares of differences between adjacent NN intervals (r-MSSD). Household PM was measured as the mass concentration of PM with an aerodynamic diameter <2.5 µm (PM2.5). We used mixed-effects models to examine the association between household PM2.5 exposure and log10-transformed HRV indices. Results After controlling for potential confounders, an interquartile range change in household PM2.5 with 1- to 4-h mean was associated with 1.25–4.31% decreases in SDNN and 0.12–3.71% decreases in r-MSSD. Stir-frying, cleaning with detergent and burning incense may increase household PM2.5 concentrations and modify the effects of household PM2.5 on HRV indices among housewives. Conclusions Indoor PM2.5 exposures were associated with decreased SDNN and r-MSSD among housewives, especially during stir-frying, cleaning with detergent and burning incense. PMID:24594880

  17. The exposure history of Jilin and production rates of cosmogenic nuclides

    NASA Technical Reports Server (NTRS)

    Heusser, G.

    1986-01-01

    Jilin, the largest known story meteorite, is a very suitable object for studying the systematics of cosmic ray produced nuclides in stony meteorites. Its well established two stage exposure history even permits to gain information about two different irradiation geometries (2pi and 4pi). All stable and long-lived cosmogenic nuclides measured in Jilin so far correlate well with each other. An example is shown where the Al-26 activities are plotted vs. the spallogenic Ne-21 concentration. These records of cosmic-ray interaction in Jilin can be used both to determine the history of the target and to study the nature of production rate profiles. This is unavoidably a bootstrap process, involving studying one with assumption about the other. Production rate equations are presented and discussed.

  18. Etching rate control of mask material for XeF2 etching using UV exposure

    NASA Astrophysics Data System (ADS)

    Sugano, Koji; Tabata, Osamu

    2001-09-01

    A new technique to control etching rates of mask materials during XeF2 etching was proposed. By exposing Si sample with SiO2 and Si3N4 as mask materials to UV light of 3 W/cm2 during XeF2 etching, the etching rates of SiO2 and Si3N4 were dramatically increased from 2.52 angstrom/pulse to 42.0 angstrom/pulse and from 27.3 angstrom/pulse to 403 angstrom/pulse, respectively. This new technique allows us to remove the mask material selectively and change the mask pattern by UV light exposure during in- situ etching process without additional photolithography step and opens a new silicon micromachining process for 3- dimensional fabrication. The multi-step Si structure was successfully realized by this technique.

  19. Role of procollagen mRNA levels in controlling the rate of procollagen synthesis.

    PubMed Central

    Rowe, L B; Schwarz, R I

    1983-01-01

    Two factors must be present for primary avian tendon cells to commit 50% of their total protein production to procollagen: ascorbate and high cell density. Scorbutic primary avian tendon cells at high cell density (greater than 4 X 10(4) cells per cm2) responded to the addition of ascorbate by a sixfold increase in the rate of procollagen synthesis. The kinetics were biphasic, showing a slow increase during the first 12 h followed by a more rapid rise to a maximum after 36 to 48 h. In contrast, after ascorbate addition, the level of accumulated cytoplasmic procollagen mRNA (alpha 2) showed a 12-h lag followed by a slow linear increase requiring 60 to 72 h to reach full induction. At all stages of the induction process, the relative increase in the rate of procollagen synthesis over the uninduced state exceeded the relative increase in the accumulation of procollagen mRNA. A similar delay in mRNA induction was observed when the cells were grown in an ascorbate-containing medium but the cell density was allowed to increase. In all cases, the rate of procollagen synthesis peaked approximately 24 h before the maximum accumulation of procollagen mRNA. The kinetics for the increase in procollagen synthesis are not, therefore, in agreement with the simple model that mRNA levels are the rate-limiting factor in the collagen pathway. We propose that the primary control point is at a later step. Further support for this idea comes from inhibitor studies, using alpha, alpha'-dipyridyl to block ascorbate action. In the presence of 0.3 mM alpha, alpha'-dipyridyl there was a specific two- to threefold decrease in procollagen production after 4 h, but this was unaccompanied by a drop in procollagen mRNA levels. Therefore, inhibitor studies give further support to the idea that primary action of ascorbate is to release a post-translational block. Images PMID:6835211

  20. Exposure to Persistent Organic Pollutants Increases Hospitalization Rates for Myocardial Infarction with Comorbid Hypertension

    PubMed Central

    Sergeev, Alexander V.; Carpenter, David O.

    2010-01-01

    Studies suggest that environmental exposure to persistent organic pollutants (POPs) may be an emerging risk factor for ischemic heart disease, including acute myocardial infarction (AMI). However, some studies indicate that exposure to POPs may also be a risk factor for hypertension, a well-established risk factor for AMI. To investigate effect of POPs on the environmental burden of cardiovascular disease, a study of AMI with comorbid hypertension in populations environmentally exposed to persistent organic pollutants, based on the zip code of residence, was conducted. Data on hospital discharges for AMI with comorbid hypertension were obtained from the New York Statewide Planning and Research Cooperative System for 1993–2004. Patients residing in zip codes containing or abutting POPs contaminated sites were considered environmentally exposed. Relative risks (RR) — with corresponding 95% confidence intervals (95% CI) — of hospitalization for AMI with comorbid hypertension were estimated by Poisson regression, adjusting for known confounders. Adjusted hospitalization rates for AMI with comorbid hypertension were 12.4% higher in populations residing in proximity to a POPs site (adjusted RR = 1.124, 95% CI 1.025–1.233, p < 0.05), compared to not in proximity to a POPs site. Also, hospitalization rates for AMI with comorbid hypertension were higher in males than in females (adjusted RR = 2.157, 95% CI 2.100–2.215, p < 0.05), in African Americans than in Caucasians (adjusted RR = 1.631, 95% CI 1.483–1.794, p < 0.05), and in older age groups (p for trend <0.05). These findings are consistent with the established effects of non-modifiable risk factors and serve as indirect quality indicators for our model. In conclusion, our results support the hypothesis that environmental exposure to POPs increases the burden of cardiovascular disease in exposed populations. PMID:21562627

  1. Exposure to Persistent Organic Pollutants Increases Hospitalization Rates for Myocardial Infarction with Comorbid Hypertension.

    PubMed

    Sergeev, Alexander V; Carpenter, David O

    2010-03-23

    Studies suggest that environmental exposure to persistent organic pollutants (POPs) may be an emerging risk factor for ischemic heart disease, including acute myocardial infarction (AMI). However, some studies indicate that exposure to POPs may also be a risk factor for hypertension, a well-established risk factor for AMI. To investigate effect of POPs on the environmental burden of cardiovascular disease, a study of AMI with comorbid hypertension in populations environmentally exposed to persistent organic pollutants, based on the zip code of residence, was conducted. Data on hospital discharges for AMI with comorbid hypertension were obtained from the New York Statewide Planning and Research Cooperative System for 1993-2004. Patients residing in zip codes containing or abutting POPs contaminated sites were considered environmentally exposed. Relative risks (RR) - with corresponding 95% confidence intervals (95% CI) - of hospitalization for AMI with comorbid hypertension were estimated by Poisson regression, adjusting for known confounders. Adjusted hospitalization rates for AMI with comorbid hypertension were 12.4% higher in populations residing in proximity to a POPs site (adjusted RR = 1.124, 95% CI 1.025-1.233, p < 0.05), compared to not in proximity to a POPs site. Also, hospitalization rates for AMI with comorbid hypertension were higher in males than in females (adjusted RR = 2.157, 95% CI 2.100-2.215, p < 0.05), in African Americans than in Caucasians (adjusted RR = 1.631, 95% CI 1.483-1.794, p < 0.05), and in older age groups (p for trend <0.05). These findings are consistent with the established effects of non-modifiable risk factors and serve as indirect quality indicators for our model. In conclusion, our results support the hypothesis that environmental exposure to POPs increases the burden of cardiovascular disease in exposed populations.

  2. Acute Changes in Heart Rate Variability in Subjects With Diabetes Following a Highway Traffic Exposure

    PubMed Central

    Laumbach, Robert J.; Rich, David Q.; Gandhi, Sampada; Amorosa, Louis; Schneider, Stephen; Zhang, Junfeng; Ohman-Strickland, Pamela; Gong, Jicheng; Lelyanov, Oleksiy; Kipen, Howard M.

    2014-01-01

    Objective To pilot a protocol to evaluate acute cardiovascular effects in in-vehicle exposure to traffic air pollutants in people with diabetes. Methods Twenty-one volunteers with type 2 diabetes were passengers on 90- to 110-minute car rides on a busy highway. We measured in-vehicle particle number and mass (PM2.5) nitrogen dioxide, and carbon monoxide and heart rate, heart rate variability (HRV), and blood pressure. Results Compared with pre-ride measurements, we found a decrease in high frequency (HF) HRV from pre-ride to next day (ratio 0.66, 95% CI = 0.47 to 0.93) and an increase in low frequency to HF ratio at post-ride (ratio 1.92, 95% CI = 1.21 to 3.05) at post-ride. Interquartile range increases in measured pollutants were associated with next-day decreases in HR HRV. Conclusions This protocol appears useful for assessing acute adverse cardiovascular effects of in-vehicle exposures among people who have diabetes. PMID:20190650

  3. Development and Evaluation of a New Air Exchange Rate Algorithm for the Stochastic Human Exposure and Dose Simulation Model

    EPA Science Inventory

    between-home and between-city variability in residential pollutant infiltration. This is likely a result of differences in home ventilation, or air exchange rates (AER). The Stochastic Human Exposure and Dose Simulation (SHEDS) model is a population exposure model that uses a pro...

  4. Metabolism and aging: effects of cold exposure on metabolic rate, body composition, and longevity in mice.

    PubMed

    Vaanholt, Lobke M; Daan, Serge; Schubert, Kristin A; Visser, G Henk

    2009-01-01

    The proposition that increased energy expenditure shortens life has a long history. The rate-of-living theory (Pearl 1928 ) states that life span and average mass-specific metabolic rate are inversely proportional. Originally based on interspecific allometric comparisons between species of mammals, the theory was later rejected on the basis of comparisons between taxa (e.g., birds have higher metabolic rates than mammals of the same size and yet live longer). It has rarely been experimentally tested within species. Here, we investigated the effects of increased energy expenditure, induced by cold exposure, on longevity in mice. Longevity was measured in groups of 60 male mice maintained at either 22 degrees C (WW) or 10 degrees C (CC) throughout adult life. Forty additional mice were maintained at both of these temperatures to determine metabolic rate (by stable isotope turnover, gas exchange, and food intake) as well as the mass of body and organs of subsets of animals at four different ages. Because energy expenditure might affect longevity by either accumulating damage or by instantaneously affecting mortality rate, we included a third group of mice exposed to 10 degrees C early in life and to 22 degrees C afterward (CW). Exposure to cold increased mean daily energy expenditure by ca. 48% (from 47.8 kJ d(-1) in WW to 70.6 kJ d(-1) in CC mice, with CW intermediate at 59.9 kJ d(-1)). However, we observed no significant differences in median life span among the groups (WW, 832 d; CC, 834 d; CW, 751 d). CC mice had reduced body mass (lifetime mean 30.7 g) compared with WW mice (33.8 g), and hence their lifetime energy potential (LEP) per gram whole-body mass had an even larger excess than per individual. Greenberg ( 1999 ) has pointed out that the size of the energetically costly organs, rather than that of the whole body, may be relevant for the rate-of-living idea. We therefore expressed LEP also in terms of energy expenditure per gram dry lean mass or per gram

  5. Gene regulation of UDP-galactose synthesis and transport: Potential rate limiting processes in initiation of milk production in humans

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lactose synthesis is believed to be rate-limiting for milk production. However, understanding the molecular events controlling lactose synthesis in humans is still rudimentary. We have utilized our established model of the RNA isolated from breast milk fat globule from 7 healthy exclusively breastfe...

  6. High exposure rates of anticoagulant rodenticides in predatory bird species in intensively managed landscapes in Denmark.

    PubMed

    Christensen, Thomas Kjær; Lassen, Pia; Elmeros, Morten

    2012-10-01

    The extensive use of anticoagulant rodenticides (ARs) for rodent control has led to widespread secondary exposure in nontarget predatory wildlife species. We investigated exposure rates and concentrations of five ARs in liver samples from five raptors and six owls from Denmark. A total of 430 birds were analysed. ARs were detected in 84-100 % of individual birds within each species. Multiple AR exposure was detected in 73 % of all birds. Average number of substances detected in individual birds was 2.2 with no differences between owls and raptors. Difenacoum, bromadiolone, and brodifacoum were the most prevalent substances and occurred in the highest concentrations. Second-generation ARs made up 96 % of the summed AR burden. Among the six core species (sample size >30), summed AR concentrations were lower in rough-legged buzzard (Buteo lagopus) and long-eared owl (Asio otus) than in barn owl (Tyto alba), buzzard (B. buteo), kestrel (Falco tinnunculus), and tawny owl (Strix aluco). There was a strong tendency for seasonal variations in the summed AR concentration with levels being lowest during autumn, which is probably related to an influx of less-exposed migrating birds from northern Scandinavia during autumn. High hepatic AR residue concentrations (>100 ng/g wet weight), which have been associated with symptoms of rodenticide poisoning and increased mortality, were recorded high frequencies (12.9-37.4 %) in five of the six core species. The results suggest that the present use of ARs in Denmark, at least locally, may have adverse effects on reproduction and, ultimately, population status in some raptors and owls. PMID:22588365

  7. Rates of fetal alcohol exposure among newborns in a high-risk obstetric unit.

    PubMed

    Goh, Y Ingrid; Hutson, Janine R; Lum, Lisa; Roukema, Henry; Gareri, Joey; Lynn, Hazel; Koren, Gideon

    2010-01-01

    Meconium fatty acid ethyl esters (FAEEs) are sensitive and specific biomarkers for prenatal alcohol exposure (PAE) in pregnancy. We recently reported a 2.5% rate of FAEE positive meconium in a general population sample of infants born in the region of Grey-Bruce, Ontario. Women in this region with high-risk pregnancies are transferred to a tertiary care facility in London, Ontario. The objective of this study was to determine, in a population-based sample, whether high-risk pregnancies are associated with an increased risk of in utero alcohol exposure. Grey-Bruce residents transferred to the high-risk obstetric unit of St. Joseph's Health Care in London, Ontario were identified and consented to this anonymous prevalence study. Meconium was collected and analyzed for FAEE using gas chromatography with mass spectrometry. The prevalence of FAEE positive meconium was compared with the population-based prevalence in the Grey-Bruce. Fifty meconium specimens were collected from August 1, 2006 to July 31, 2007. Fifteen (30%) specimens tested positive for FAEE. The results indicate that infants born in the high-risk obstetric unit had a 12-fold higher risk of screening positive for second and third trimester alcohol exposure compared with infants born in the general population of Grey-Bruce (relative risk=12.04, 95% confidence interval=6.40-22.65, P<.0001). These results suggest that the high-risk pregnancies should be screened for PAE and followed-up for potential diagnosis of fetal alcohol spectrum disorder. PMID:20584588

  8. Exposure to and fear of terror as predictors of self-rated health among apparently healthy employees.

    PubMed

    Shirom, Arie; Toker, Sharon; Shapira, Itzhak; Berliner, Shlomo; Melamed, Samuel

    2008-05-01

    The effects of exposure to terror on physical health were investigated by relating objective exposure to terror and fear of terror to self-rated health (SRH), a proxy measure of health status. Our respondents were apparently healthy (N=4,877, 38% women) adults who completed self-report questionnaires. Objective exposure was assessed by the number of terrorist attacks and their casualties in a respondent's urban area prior to her/his completion of the questionnaire. Using several alternative assessments, objective exposure to terror did not predict SRH for both the genders. As hypothesized, fear of terror negatively predicted SRH for both females and males (beta=-0.04, -0.05, respectively). The effects of subjective and objective exposure were not found to be more pronounced among women relative to men, thus disconfirming our hypotheses in this regard. Our findings suggest that living under continuous fear of terror may adversely influence physical health irrespective of objective exposure.

  9. Fluoride exposure regulates the elongation phase of protein synthesis in cultured Bergmann glia cells.

    PubMed

    Flores-Méndez, Marco; Ramírez, Diana; Alamillo, Nely; Hernández-Kelly, Luisa C; Del Razo, Luz María; Ortega, Arturo

    2014-08-17

    Fluoride is an environmental pollutant present in dental products, food, pesticides and water. The latter, is the greatest source of exposure to this contaminant. Structural and functional damages to the central nervous system are present in exposed population. An established consequence of the neuronal is the release of a substantial amount of glutamate to the extracellular space, leading to an excitotoxic insult. Glutamate exerts its actions through the activation of specific plasma membrane receptors and transporters present in neurons and in glia cells and it is the over-activation of glutamate receptors and transporters, the biochemical hallmark of neuronal and oligodendrocyte cell death. In this context, taking into consideration that fluoride leads to degeneration of cerebellar cells, we took the advantage of the well-established model of cerebellar Bergmann glia cultures to gain insight into the molecular mechanisms inherent to fluoride neurotoxicity that might be triggered in glia cells. We could establish that fluoride decreases [(35)S]-methionine incorporation into newly synthesized polypeptides, in a time-dependent manner, and that this halt in protein synthesis is the result of a decrease in the elongation phase of translation, mediated by an augmentation of eukaryotic elongation factor 2 phosphorylation. These results favor the notion of glial cells as targets of fluoride toxicity and strengthen the idea of a critical involvement of glia cells in the function and dysfunction of the brain. PMID:24954634

  10. Estimating dose rates to organs as a function of age following internal exposure to radionuclides

    SciTech Connect

    Leggett, R.W.; Eckerman, K.F.; Dunning, D.E. Jr.; Cristy, M.; Crawford-Brown, D.J.; Williams, L.R.

    1984-03-01

    The AGEDOS methodology allows estimates of dose rates, as a function of age, to radiosensitive organs and tissues in the human body at arbitrary times during or after internal exposure to radioactive material. Presently there are few, if any, radionuclides for which sufficient metabolic information is available to allow full use of all features of the methodology. The intention has been to construct the methodology so that optimal information can be gained from a mixture of the limited amount of age-dependent, nuclide-specific data and the generally plentiful age-dependent physiological data now available. Moreover, an effort has been made to design the methodology so that constantly accumulating metabolic information can be incorporated with minimal alterations in the AGEDOS computer code. Some preliminary analyses performed by the authors, using the AGEDOS code in conjunction with age-dependent risk factors developed from the A-bomb survivor data and other studies, has indicated that the doses and subsequent risks of eventually experiencing radiogenic cancers may vary substantially with age for some exposure scenarios and may be relatively invariant with age for other scenarios. We believe that the AGEDOS methodology provides a convenient and efficient means for performing the internal dosimetry.

  11. Determining biotransformation rates of PAH in fish using a static exposure system

    SciTech Connect

    Maagd, P.G.J. de; Sijm, D.T.H.M.; Opperhuizen, A.

    1994-12-31

    In-order to quantify the influence of biotransformation on bioconcentration, juvenile fathead minnows were exposed to aqueous solutions of PAH under static conditions. During the two days of exposure both fish and water samples were taken and analyzed to determine the change in PAH concentrations in both phases with time. A numerical mathematical model was developed to calculate uptake rate constants (k{sub 1}), physico-chemical elimination rate constants (k{sub m}) and biotransformation rate constants (k{sub 2}) from concentrations in fish and water. The model assumes that biotransformation is the only process that is responsible for loss of PAH from the fish-water system. Control experiments were performed to correct for evaporation, degradation and sorption. Of the PAH tested so far (naphthalene, anthracene, phenanthrene, fluoranthene and benzo[a]anthracene) the influence of biotransformation on bioconcentration is most significant for benzo[a]anthracene and fluoranthene. Biotransformation reduced the bioconcentration of benz[a]anthracene with about an order of magnitude.

  12. Risky business: trauma exposure and rate of posttraumatic stress disorder in African American children and adolescents.

    PubMed

    Hunt, Kristin L; Martens, Patricia M; Belcher, Harolyn M E

    2011-06-01

    Demographics, parental risk factors, and experiencing interpersonal trauma (domestic violence, community violence, and physical and sexual abuse) are related to childhood posttraumatic stress disorder (PTSD). Little is known about these factors and the risk of PTSD in African American children. This study examined associations between PTSD symptoms and gender, age, parent mental illness, parent substance abuse, and interpersonal trauma in African American children. Participants were 257 children and adolescents, ages 8-17 years (M = 11.7, SD = 2.5), who received outpatient mental health treatment. Being female and witnessing domestic violence was associated with more PTSD symptoms. Exposure to community violence and physical abuse increased the odds of clinically significant PTSD symptomatology by more than 2 times. The rate of PTSD (16%) was lower in the current study than in other same-age study populations (25%-40%). Risk factors and identification strategies for PTSD are discussed.

  13. A Monte Carlo program to calculate the exposure rate from airborne radioactive gases inside a nuclear reactor containment building.

    PubMed

    Sherbini, S; Tamasanis, D; Sykes, J; Porter, S W

    1986-12-01

    A program was developed to calculate the exposure rate resulting from airborne gases inside a reactor containment building. The calculations were performed at the location of a wall-mounted area radiation monitor. The program uses Monte Carlo techniques and accounts for both the direct and scattered components of the radiation field at the detector. The scattered component was found to contribute about 30% of the total exposure rate at 50 keV and dropped to about 7% at 2000 keV. The results of the calculations were normalized to unit activity per unit volume of air in the containment. This allows the exposure rate readings of the area monitor to be used to estimate the airborne activity in containment in the early phases of an accident. Such estimates, coupled with containment leak rates, provide a method to obtain a release rate for use in offsite dose projection calculations.

  14. Comparison of rates of enamel synthesis in impeded and unimpeded rat incisors.

    PubMed

    Skobe, Z; Heeley, J D; Dobeck, J M; Prostak, K S; Maravelis, L; Stern, D N

    1993-01-01

    Periodic intubations of rats with solutions of fluoride (F) lead to the appearance of bands of disrupted pigmentation in continuously erupting incisors. Distances between fluorotic bands reflect time intervals between intubations. In this experiment, the periodicity of fluorotic banding was used for estimation of the rate of enamel synthesis in impeded and unimpeded rat incisors. Rats kept on a low-F diet and distilled water were intubated two or four times per week with 2 mg NaF/150 g body weight. In a group of rats, one of the mandibular incisors was cut at the gingival margin after two weeks, and intubations were continued for an additional two weeks. In another group of F-intubated rats, incisors were cut or notched at the gingival margin twice, six days apart. Control rats either received the same periodic F intubations or were maintained on the low-F diet without intubation. Measurements of spacing between fluorotic bands were identical in impeded and unimpeded teeth, even though the latter erupted at a faster rate. In an unimpeded mandibular incisors, there was a significant elongation of the secretory zone and a shortening of the pigmentation zone, resulting in reduced pigmentation intensity of the erupted portions of the teeth. The results show that the rate of enamel synthesis is independent of the eruption rate.

  15. Measurements of environmental radiation exposure dose rates at selected sites in Brazil.

    PubMed

    Pfeiffer, W C; Penna-Franca, E; Ribeiro, C C; Nogueira, A R; Londres, H; Oliveira, A E

    1981-12-01

    Two types of portable instruments were developed by the former Health and Safety Laboratory of the U.S. Atomic Energy Commission to characterize external gamma radiation fields and to estimate individual exposure dose rates from major natural or fission radionuclides distributed in the soil: a pressurized ionization chamber and a NaI(T1) gamma-ray spectrometer. The two instruments were used to measure environmental radiation exposure rates at three distinct geological areas of Brazil: - in the towns of Guarapari and Meaípe located on the monazite sand belt, ES. - on the vicinities of the uranium mine of Poços de Caldas, MG. - around the site of the Brazilian first nuclear power plant, in Angra dos Reis, RJ. The radiometric survey demonstrated once more the usefulness and versatility of the two instruments used. The measurements around the nuclear installations of Poços de Caldas and Angra dos Reis, allowed a rapid assessment of the local radiation background and its variability, as well as the selection of stations for the routine monitoring program. Radioactive anomalies were detected and characterized previously to the start of plant operations. The survey in Guarapari and Meaípe confirmed the results obtained by Roser and Cullen in 1958 and 1962, except on sites where considerable changes took place since then. The spectrometric measurements gave estimations of the relative proportion of 40K, 238U and 232Th series in the ground and also indications on the homogeneity of their distribution in the soil.

  16. Influence of metal concentrations, percent salinity, and length of exposure on the metabolic rate of fathead minnows (Pimephales promelas).

    PubMed

    Pistole, David H; Peles, John D; Taylor, Kelly

    2008-07-01

    Understanding the effects of chemical toxicants on energetic processes is an important aspect of ecotoxicology. However, the influence of toxicant concentration and time of exposure on metabolism in aquatic organisms is still poorly understood. The purpose of this investigation was to determine the influence of increasing levels of three stressors (Cu, Cd, percent salinity) and exposure time (24 h and 96 h) on the metabolic rate of fathead minnows (Pimephales promelas). In all 24-h exposures, there existed a threshold concentration, above which metabolic rate decreased significantly compared to the control and lower concentrations. In contrast, the metabolic rate of fish exposed for 96 h increased significantly in all concentrations compared to fish from the control. We suggest fathead minnows exhibit a consistent pattern of metabolic response to stressors, regardless of the physiological mechanisms involved, and that this response differs as a function of time of exposure.

  17. Clearance and synthesis rates of beta 2-microglobulin in patients undergoing hemodialysis and in normal subjects

    SciTech Connect

    Floege, J.; Bartsch, A.; Schulze, M.; Shaldon, S.; Koch, K.M.; Smeby, L.C. )

    1991-08-01

    Retention of {beta} 2-microglobulin in patients undergoing hemodialysis is associated with a {beta} 2-microglobulin-derived amyloidosis. Removal of {beta} 2-microglobulin by renal replacement therapy has been proposed for the prevention of this amyloidosis. Currently, however, data on the {beta} 2-microglobulin synthesis rate in patients undergoing hemodialysis are scarce, and consequently it remains speculative how much removal would be necessary to counterbalance synthesis. The plasma kinetics of iodine 131-labeled {beta} 2-microglobulin were therefore examined in 11 patients with anuria who were undergoing long-term hemodialysis. Five healthy persons served as controls. Kinetic modeling of the plasma curves showed that the data fitted a two-pool model (r2 greater than 0.96) consisting of a rapid 2 to 4 hour distribution phase followed by a less steep curve, described by the plasma (metabolic) clearance (Clp). Synthetic rates were calculated from Clp and the {beta} 2-microglobulin steady state plasma concentration (plus {beta} 2-microglobulin removal during hemodialysis in the case of high flux hemodialysis). The results showed a significantly higher Clp in normal controls as compared with patients undergoing hemodialysis (65.5 {plus minus} 12.8 ml/min (mean {plus minus} SD) versus 3.4 {plus minus} 0.7 ml/min). In contrast, the {beta} 2-microglobulin synthesis rate in the patient group (3.10 {plus minus} 0.79 mg/kg/day) was not significantly different from that of normal controls (2.40 {plus minus} 0.67 mg/kg/day), which was due to markedly elevated {beta} 2-microglobulin plasma concentrations in the patients (37.6 {plus minus} 14.1 mg/L vs 1.92 {plus minus} 0.27 mg/L). These findings suggest that the presence of end-stage renal disease does not have a significant impact on the beta 2-microglobulin generation rate.

  18. Synthesis of phenolics and flavonoids in ginger (Zingiber officinale Roscoe) and their effects on photosynthesis rate.

    PubMed

    Ghasemzadeh, Ali; Jaafar, Hawa Z E; Rahmat, Asmah

    2010-01-01

    The relationship between phenolics and flavonoids synthesis/accumulation and photosynthesis rate was investigated for two Malaysian ginger (Zingiber officinale) varieties grown under four levels of glasshouse light intensity, namely 310, 460, 630 and 790 μmol m(-2)s(-1). High performance liquid chromatography (HPLC) was employed to identify and quantify the polyphenolic components. The results of HPLC analysis indicated that synthesis and partitioning of quercetin, rutin, catechin, epicatechin and naringenin were high in plants grown under 310 μmol m(-2)s(-1). The average value of flavonoids synthesis in leaves for both varieties increased (Halia Bentong 26.1%; Halia Bara 19.5%) when light intensity decreased. Photosynthetic rate and plant biomass increased in both varieties with increasing light intensity. More specifically, a high photosynthesis rate (12.25 μmol CO(2) m(-2)s(-1) in Halia Bara) and plant biomass (79.47 g in Halia Bentong) were observed at 790 μmol m(-2)s(-1). Furthermore, plants with the lowest rate of photosynthesis had highest flavonoids content. Previous studies have shown that quercetin inhibits and salicylic acid induces the electron transport rate in photosynthesis photosystems. In the current study, quercetin was an abundant flavonoid in both ginger varieties. Moreover, higher concentration of quercetin (1.12 mg/g dry weight) was found in Halia Bara leaves grown under 310 μmol m(-2)s(-1) with a low photosynthesis rate. Furthermore, a high content of salicylic acid (0.673 mg/g dry weight) was detected in Halia Bara leaves exposed under 790 μmol m(-2)s(-1) with a high photosynthesis rate. No salicylic acid was detected in gingers grown under 310 μmol m(-2)s(-1). Ginger is a semi-shade loving plant that does not require high light intensity for photosynthesis. Different photosynthesis rates at different light intensities may be related to the absence or presence of some flavonoid and phenolic compounds. PMID:21151455

  19. Synthesis of phenolics and flavonoids in ginger (Zingiber officinale Roscoe) and their effects on photosynthesis rate.

    PubMed

    Ghasemzadeh, Ali; Jaafar, Hawa Z E; Rahmat, Asmah

    2010-11-15

    The relationship between phenolics and flavonoids synthesis/accumulation and photosynthesis rate was investigated for two Malaysian ginger (Zingiber officinale) varieties grown under four levels of glasshouse light intensity, namely 310, 460, 630 and 790 μmol m(-2)s(-1). High performance liquid chromatography (HPLC) was employed to identify and quantify the polyphenolic components. The results of HPLC analysis indicated that synthesis and partitioning of quercetin, rutin, catechin, epicatechin and naringenin were high in plants grown under 310 μmol m(-2)s(-1). The average value of flavonoids synthesis in leaves for both varieties increased (Halia Bentong 26.1%; Halia Bara 19.5%) when light intensity decreased. Photosynthetic rate and plant biomass increased in both varieties with increasing light intensity. More specifically, a high photosynthesis rate (12.25 μmol CO(2) m(-2)s(-1) in Halia Bara) and plant biomass (79.47 g in Halia Bentong) were observed at 790 μmol m(-2)s(-1). Furthermore, plants with the lowest rate of photosynthesis had highest flavonoids content. Previous studies have shown that quercetin inhibits and salicylic acid induces the electron transport rate in photosynthesis photosystems. In the current study, quercetin was an abundant flavonoid in both ginger varieties. Moreover, higher concentration of quercetin (1.12 mg/g dry weight) was found in Halia Bara leaves grown under 310 μmol m(-2)s(-1) with a low photosynthesis rate. Furthermore, a high content of salicylic acid (0.673 mg/g dry weight) was detected in Halia Bara leaves exposed under 790 μmol m(-2)s(-1) with a high photosynthesis rate. No salicylic acid was detected in gingers grown under 310 μmol m(-2)s(-1). Ginger is a semi-shade loving plant that does not require high light intensity for photosynthesis. Different photosynthesis rates at different light intensities may be related to the absence or presence of some flavonoid and phenolic compounds.

  20. Derivation of heating rate dependent exposure strategies for the selective laser melting of thermoplastic polymers

    NASA Astrophysics Data System (ADS)

    Drummer, Dietmar; Drexler, Maximilian; Wudy, Katrin

    2015-05-01

    The selective laser melting of polymer powder is for rapid prototyping applications an established technology, although a lack in basic process knowledge appears. Considering demands of series production the selective laser melting technique is faced with varies challenges concerning processable material systems, process strategies and part properties. Consequently basic research is necessary to shift from rapid prototyping to rapid manufacturing of small lot sized series. Based on basic research the high potential of selective laser melting for the production of complex parts without any tools can be opened up. For the derivation of part quality increasing process strategies knowledge about interactions between sub-processes of selective laser melting and resulting part properties is necessary. The selective laser melting consists of three major sub-processes: Geometry exposure, tempering and powder feeding. According to the interaction of sub-processes resulting temperature fields during the selective laser melting process determine the part properties by changing micro structural pore number and distribution. Beneath absolute temperatures also the time-dependency of the thermal fields influences the porosity of molten parts. Present process strategies tend to decrease building time by increasing scanning speed and laser power. Although the absolute energy input into the material is constant for increasing scanning speed and laser power in the same ratio, time dependent material effects are neglected. The heating rate is a combined parameter derived from absolute temperature and time. Within the paper the authors analyze the basic interactions between different heating rates and part properties (e.g. porosity, mechanical strengths). Therefore with different heating rates produced specimens are analyzed with imaging technologies as well as mechanical tests. Based on the done basic investigations new heating rate dependent process strategies can be established

  1. Assessing the reproducibility of fractional rates of protein synthesis in muscle tissue measured using the flooding dose technique.

    PubMed

    McCarthy, Ian D; Brown, James

    2016-07-01

    The flooding dose technique of Garlick et al. (1980) has become the main method for measuring tissue and whole-animal rates of protein synthesis in ectotherms. However, single tissue samples are used to determine rates of protein synthesis and no studies have examined the pattern of flooding in large tissues such as the white muscle in fishes, which can comprise up to 55% of the wet body mass of a fish and which is poorly perfused. The present study has examined, for the first time, the patterns of flooding and measured rates of protein synthesis in five different regions of the white muscle in the Arctic charr Salvelinus alpinus ranging in size from 25g to 1.6kg following a flooding dose injection of L-[(3)H]-phenylalanine. The results indicate that the degree of flooding (i.e. free pool specific radioactivity relative to that of the injection solution) and elevation in free phenylalanine concentrations can vary between regions but the calculated fractional rates of protein synthesis were similar in four of the five regions studied. The variability in rates of protein synthesis increased with body size with greater variability observed between regions for fish >1kg in body mass. For consistency between studies, it is recommended that samples are taken from the epaxial muscle in the region below the dorsal fin when measuring fractional rates of white muscle synthesis in fishes. PMID:26970581

  2. Assessing the reproducibility of fractional rates of protein synthesis in muscle tissue measured using the flooding dose technique.

    PubMed

    McCarthy, Ian D; Brown, James

    2016-07-01

    The flooding dose technique of Garlick et al. (1980) has become the main method for measuring tissue and whole-animal rates of protein synthesis in ectotherms. However, single tissue samples are used to determine rates of protein synthesis and no studies have examined the pattern of flooding in large tissues such as the white muscle in fishes, which can comprise up to 55% of the wet body mass of a fish and which is poorly perfused. The present study has examined, for the first time, the patterns of flooding and measured rates of protein synthesis in five different regions of the white muscle in the Arctic charr Salvelinus alpinus ranging in size from 25g to 1.6kg following a flooding dose injection of L-[(3)H]-phenylalanine. The results indicate that the degree of flooding (i.e. free pool specific radioactivity relative to that of the injection solution) and elevation in free phenylalanine concentrations can vary between regions but the calculated fractional rates of protein synthesis were similar in four of the five regions studied. The variability in rates of protein synthesis increased with body size with greater variability observed between regions for fish >1kg in body mass. For consistency between studies, it is recommended that samples are taken from the epaxial muscle in the region below the dorsal fin when measuring fractional rates of white muscle synthesis in fishes.

  3. Comparison of the Effects of Ornithine and Arginine on the Brain Protein Synthesis Rate in Young Rats.

    PubMed

    Suzumura, Shoko; Tujioka, Kazuyo; Yamada, Takashi; Yokogoshi, Hidehiko; Akiduki, Saori; Hishida, Yukihiro; Tsutsui, Kazumi; Hayase, Kazutoshi

    2015-01-01

    Brain protein synthesis and the plasma concentration of growth hormone (GH) are sensitive to dietary ornithine. The purpose of this study was to determine whether dietary arginine, the metabolite of ornithine, affects the brain protein synthesis, and to that end, the effects of arginine on brain protein synthesis were compared with that of ornithine treatment in young rats. Two experiments were done on five or three groups of young rats (5-wk-old) given 0%, 0.25%, 0.5%, 0.7% arginine or 0.7% ornithine-HCl added to a 20% casein diet for 1 d (only one 3 h period) (Experiment 1), or given a diet containing 0% or 0.7% ornithine-HCl or 0.7% arginine added to a 20% casein diet (Experiment 2). The concentrations of plasma growth hormone (GH) and fractional rates of protein synthesis in the brains increased significantly with the 20% casein+0.7% arginine diet and still more with the 20% casein+0.7% ornithine diet compared with the 20% casein diet alone. In the cerebral cortex and cerebellum, the RNA activity [g protein synthesized/(g RNA•d)] significantly correlated with the fractional rate of protein synthesis. The RNA concentration (mg RNA/g protein) was also related to the fractional rate of protein synthesis in these organs. The results suggest that the treatment with arginine is likely to increase the concentrations of GH and the rate of brain protein synthesis in rats, and that the effects of arginine on brain protein synthesis and GH concentration were lower than that of ornithine. The RNA activity is at least partly related to the fractional rate of brain protein synthesis.

  4. Aortic baroreflex control of heart rate after 15 days of simulated microgravity exposure

    NASA Technical Reports Server (NTRS)

    Crandall, Craig G.; Engelke, Keith A.; Convertino, Victor A.; Raven, Peter B.

    1994-01-01

    To determine the effects of simulated microgravity on aortic baroreflex control of heart rate, we exposed seven male subjects to 15 days of bed rest in the 6 deg head-down position. The sensitivity of the aortic-cardiac baroreflex was determined during a steady-state phenylephrine-induced increase in mean arterial pressure combined with lower body negative pressure to counteract central venous pressure increases and neck pressure to offset the increased carotid sinus transmural pressure. The aortic-cardiac baroreflex gain was assessed by determining the ratio of the change in heart rate to the change in mean arterial pressure between baseline conditions and aortic baroreceptor-isolated conditions (i.e., phenylephrine + lower body negative pressure + neck pressure stage). Fifteen days of head-down tilt increased the gain of the aortic-cardiac baroreflex. Reductions in blood volume and/or maximal aerobic capacity may represent the underlying mechanism(s) responsible for increased aortic baroreflex responsiveness after exposure to a ground-based analogue of microgravity.

  5. Time Course of Heart Rate Variability Response to PM2.5 Exposure from Secondhand Smoke

    PubMed Central

    Garza, Jennifer L.; Mittleman, Murray A.; Zhang, Jinming; Christiani, David C.; Cavallari, Jennifer M

    2016-01-01

    Purpose: Exposure to secondhand smoke (SHS) has been associated with decreased heart rate variability (HRV). However, the time course of this association is unclear. Therefore, the objective of this study was to investigate the association between 15–240 minute SHS-related fine particulate matter (PM2.5) moving averages and indices of HRV. Methods: With a panel study design, we used personal monitors to continuously measure PM2.5 and HRV of 35 participants who were exposed to SHS for approximately 6 hours. Results: We observed negative, significant associations between 5-minute HRV indices and 15 minute PM2.5 moving averages and 240 minute PM2.5 moving averages: there was a significant (p<0.01) 7.5% decrease in the 5-minute square root of the mean squared differences of successive normal heart beats associated with (RMSSD), and a significant (p<0.01) 14.7% decrease in the 5-minute high frequency (HF) power associated with the 15 minute PM2.5 moving averages; there was also a significant (p<0.01) 46.9% decrease in the 5-minute RMSSD, and a significant (p<0.01) 77.7% decrease in the 5-minute high frequency (HF) power associated with the 240 minute PM2.5 moving averages. Conclusions: Our findings that exposure to SHS related PM2.5 was associated with HRV support the hypothesis that SHS can affect the cardiovascular system. The negative associations reported between short and longer term PM2.5 and HRV indicate adverse effects of SHS on the cardiovascular system. PMID:27223894

  6. Fetal death and reduced birth rates associated with exposure to lead-contaminated drinking water.

    PubMed

    Edwards, Marc

    2014-01-01

    This ecologic study notes that fetal death rates (FDR) during the Washington DC drinking water "lead crisis" (2000-2004) peaked in 2001 when water lead levels (WLLs) were highest, and were minimized in 2004 after public health interventions were implemented to protect pregnant women. Changes in the DC FDR vs neighboring Baltimore City were correlated to DC WLL (R(2) = 0.72). Birth rates in DC also increased versus Baltimore City and versus the United States in 2004-2006, when consumers were protected from high WLLs. The increased births in DC neighborhoods comparing 2004 versus 2001 was correlated to the incidence of lead pipes (R(2) = 0.60). DC birth rates from 1999 to 2007 correlated with proxies for maternal blood lead including the geometric mean blood lead in DC children (R(2) = 0.68) and the incidence of lead poisoning in children under age 1.3 years (R(2) = 0.64). After public health protections were removed in 2006, DC FDR spiked in 2007-2009 versus 2004-2006 (p < 0.05), in a manner consistent with high WLL health risks to consumers arising from partial lead service line replacements, and DC FDR dropped to historically low levels in 2010-2011 after consumers were protected and the PSLR program was terminated. Re-evaluation of a historic construction-related miscarriage cluster in the USA Today Building (1987-1988), demonstrates that high WLLs from disturbed plumbing were a possible cause. Overall results are consistent with prior research linking increased lead exposure to higher incidence of miscarriages and fetal death, even at blood lead elevations (≈5 μg/dL) once considered relatively low.

  7. Fetal death and reduced birth rates associated with exposure to lead-contaminated drinking water.

    PubMed

    Edwards, Marc

    2014-01-01

    This ecologic study notes that fetal death rates (FDR) during the Washington DC drinking water "lead crisis" (2000-2004) peaked in 2001 when water lead levels (WLLs) were highest, and were minimized in 2004 after public health interventions were implemented to protect pregnant women. Changes in the DC FDR vs neighboring Baltimore City were correlated to DC WLL (R(2) = 0.72). Birth rates in DC also increased versus Baltimore City and versus the United States in 2004-2006, when consumers were protected from high WLLs. The increased births in DC neighborhoods comparing 2004 versus 2001 was correlated to the incidence of lead pipes (R(2) = 0.60). DC birth rates from 1999 to 2007 correlated with proxies for maternal blood lead including the geometric mean blood lead in DC children (R(2) = 0.68) and the incidence of lead poisoning in children under age 1.3 years (R(2) = 0.64). After public health protections were removed in 2006, DC FDR spiked in 2007-2009 versus 2004-2006 (p < 0.05), in a manner consistent with high WLL health risks to consumers arising from partial lead service line replacements, and DC FDR dropped to historically low levels in 2010-2011 after consumers were protected and the PSLR program was terminated. Re-evaluation of a historic construction-related miscarriage cluster in the USA Today Building (1987-1988), demonstrates that high WLLs from disturbed plumbing were a possible cause. Overall results are consistent with prior research linking increased lead exposure to higher incidence of miscarriages and fetal death, even at blood lead elevations (≈5 μg/dL) once considered relatively low. PMID:24321041

  8. T1 Relaxation Rate (R1) Indicates Nonlinear Mn Accumulation in Brain Tissue of Welders With Low-Level Exposure

    PubMed Central

    Lee, Eun-Young; Flynn, Michael R.; Du, Guangwei; Lewis, Mechelle M.; Fry, Rebecca; Herring, Amy H.; Van Buren, Eric; Van Buren, Scott; Smeester, Lisa; Kong, Lan; Yang, Qing; Mailman, Richard B.; Huang, Xuemei

    2015-01-01

    Although the essential element manganese (Mn) is neurotoxic at high doses, the effects of lower exposure are unclear. MRI T1-weighted (TIW) imaging has been used to estimate brain Mn exposure via the pallidal index (PI), defined as the T1W intensity ratio in the globus pallidus (GP) versus frontal white matter (FWM). PI may not, however, be sensitive to Mn in GP because Mn also may accumulate in FWM. This study explored: (1) whether T1 relaxation rate (R1) could quantify brain Mn accumulation more sensitively; and (2) the dose-response relationship between estimated Mn exposure and T1 relaxation rate (R1). Thirty-five active welders and 30 controls were studied. Occupational questionnaires were used to estimate hours welding in the past 90 days (HrsW) and lifetime measures of Mn exposure. T1W imaging and T1-measurement were utilized to generate PI and R1 values in brain regions of interest (ROIs). PI did not show a significant association with any measure of Mn and/or welding-related exposure. Conversely, in several ROIs, R1 showed a nonlinear relationship to HrsW, with R1 signal increasing only after a critical exposure was reached. The GP had the greatest rate of Mn accumulation. Welders with higher exposure showed significantly higher R1 compared either with controls or with welders with lower exposure. Our data are additional evidence that Mn accumulation can be assessed more sensitively by R1 than by PI. Moreover, the nonlinear relationship between welding exposure and Mn brain accumulation should be considered in future studies and policies. PMID:25953701

  9. The Relationship of Practice Exposure and Injury Rate on Game Performance and Season Success in Professional Male Basketball

    PubMed Central

    Caparrós, Toni; Alentorn-Geli, Eduard; Myer, Gregory D.; Capdevila, Lluís; Samuelsson, Kristian; Hamilton, Bruce; Rodas, Gil

    2016-01-01

    The objectives of this study were to determine the relationship among game performance, injury rate, and practice exposure in a professional male basketball team. A retroospective analysis of prospective collected data was conducted over seven consecutive seasons (2007/2008 to 2013/2014). Data collection included sports performance during competition (statistical evaluation), injury rate, and total exposure (games and practices). Over the surveillance period, 162 injuries (91 practice; 71 matches) occurred over 32,668 hours of exposure (556 games and 2005 practices). There was a strong positive correlation between: 1) exposure (total number of practices and hours of exposure) and the total number of injuries (r = 0.77; p = 0.04); 2) exposure (total hours of exposure and total hours of practice exposure) and performance (total team ranking) (r = 0.77 and p = 0.04, and r = 0.8 and p = 0.03, respectively); and 3) total number of injuries and performance (total team ranking) (r = 0.84; p = 0.02). While increasing practice and competition time is related to greater team performance, it also increases the number of injuries. However, higher injury rates were not associated with worse overall team performance. Efforts to reduce high-risk activity during practice, optimally replaced with injury prevention training, might help to reduce injury risk. Key points Increasing practice and competition time is related to greater team performance. Increasing practice and competition time increases the number of injuries. Higher injury rates were not associated with worse overall team performance. PMID:27803617

  10. Arginine depletion by arginine deiminase does not affect whole protein metabolism or muscle fractional protein synthesis rate in mice.

    PubMed

    Marini, Juan C; Didelija, Inka Cajo

    2015-01-01

    Due to the absolute need for arginine that certain cancer cells have, arginine depletion is a therapy in clinical trials to treat several types of cancers. Arginine is an amino acids utilized not only as a precursor for other important molecules, but also for protein synthesis. Because arginine depletion can potentially exacerbate the progressive loss of body weight, and especially lean body mass, in cancer patients we determined the effect of arginine depletion by pegylated arginine deiminase (ADI-PEG 20) on whole body protein synthesis and fractional protein synthesis rate in multiple tissues of mice. ADI-PEG 20 successfully depleted circulating arginine (<1 μmol/L), and increased citrulline concentration more than tenfold. Body weight and body composition, however, were not affected by ADI-PEG 20. Despite the depletion of arginine, whole body protein synthesis and breakdown were maintained in the ADI-PEG 20 treated mice. The fractional protein synthesis rate of muscle was also not affected by arginine depletion. Most tissues (liver, kidney, spleen, heart, lungs, stomach, small and large intestine, pancreas) were able to maintain their fractional protein synthesis rate; however, the fractional protein synthesis rate of brain, thymus and testicles was reduced due to the ADI-PEG 20 treatment. Furthermore, these results were confirmed by the incorporation of ureido [14C]citrulline, which indicate the local conversion into arginine, into protein. In conclusion, the intracellular recycling pathway of citrulline is able to provide enough arginine to maintain protein synthesis rate and prevent the loss of lean body mass and body weight.

  11. Effects of Moxa (Folium Artemisiae argyi) Smoke Exposure on Heart Rate and Heart Rate Variability in Healthy Young Adults: A Randomized, Controlled Human Study

    PubMed Central

    Cui, Yingxue; Zhao, Baixiao; Huang, Yuhai; Chen, Zhanghuang; Liu, Ping; Huang, Jian; Lao, Lixing

    2013-01-01

    Objective. To determine the effects of the moxa smoke on human heart rate (HR) and heart rate variability (HRV). Methods. Fifty-five healthy young adults were randomly divided into experimental (n = 28) and control (n = 27) groups. Experimental subjects were exposed to moxa smoke (2.5 ± 0.5 mg/m3) twice for 25 minutes in one week. ECG monitoring was performed before, during, and after exposure. Control subjects were exposed to normal indoor air in a similar environment and similarly monitored. Followup was performed the following week. Short-term (5 min) HRV parameters were analyzed with HRV analysis software. SPSS software was used for statistical analysis. Results. During and after the first exposure, comparison of percentage changes or changes in all parameters between groups showed no significant differences. During the second exposure, percentage decrease in HR, percentage increases in lnTP, lnHF, lnLF, and RMSSD, and increase in PNN50 were significantly greater in the experimental group than in control. Conclusion. No significant adverse HRV effects were associated with this clinically routine 25-minute exposure to moxa smoke, and the data suggests that short-term exposure to moxa smoke might have positive regulating effects on human autonomic function. Further studies are warranted to confirm these findings. PMID:23762143

  12. Association of soil arsenic and nickel exposure with cancer mortality rates, a town-scale ecological study in Suzhou, China.

    PubMed

    Chen, Kai; Liao, Qi Lin; Ma, Zong Wei; Jin, Yang; Hua, Ming; Bi, Jun; Huang, Lei

    2015-04-01

    Heavy metals and arsenic are well-known carcinogens. However, few studies have examined whether soil heavy metals and arsenic concentrations associate with cancer in the general population. In this ecological study, we aimed to evaluate the association of heavy metals and arsenic in soil with cancer mortality rates during 2005-2010 in Suzhou, China, after controlling for education and smoking prevalence. In 2005, a total of 1683 soil samples with a sampling density of one sample every 4 km(2) were analyzed. Generalized linear model with a quasi-Poisson regression was applied to evaluate the association between town-scale cancer mortality rates and soil heavy metal concentrations. Results showed that soil arsenic exposure had a significant relationship with colon, gastric, kidney, lung, and nasopharyngeal cancer mortality rates and soil nickel exposure was significantly associated with liver and lung cancer. The associations of soil arsenic and nickel exposure with colon, gastric, kidney, and liver cancer in male were higher than those in female. The observed associations of soil arsenic and nickel with cancer mortality rates were less sensitive to alternative exposure metrics. Our findings would contribute to the understanding of the carcinogenic effect of soil arsenic and nickel exposure in general population. PMID:25410308

  13. Association of soil arsenic and nickel exposure with cancer mortality rates, a town-scale ecological study in Suzhou, China.

    PubMed

    Chen, Kai; Liao, Qi Lin; Ma, Zong Wei; Jin, Yang; Hua, Ming; Bi, Jun; Huang, Lei

    2015-04-01

    Heavy metals and arsenic are well-known carcinogens. However, few studies have examined whether soil heavy metals and arsenic concentrations associate with cancer in the general population. In this ecological study, we aimed to evaluate the association of heavy metals and arsenic in soil with cancer mortality rates during 2005-2010 in Suzhou, China, after controlling for education and smoking prevalence. In 2005, a total of 1683 soil samples with a sampling density of one sample every 4 km(2) were analyzed. Generalized linear model with a quasi-Poisson regression was applied to evaluate the association between town-scale cancer mortality rates and soil heavy metal concentrations. Results showed that soil arsenic exposure had a significant relationship with colon, gastric, kidney, lung, and nasopharyngeal cancer mortality rates and soil nickel exposure was significantly associated with liver and lung cancer. The associations of soil arsenic and nickel exposure with colon, gastric, kidney, and liver cancer in male were higher than those in female. The observed associations of soil arsenic and nickel with cancer mortality rates were less sensitive to alternative exposure metrics. Our findings would contribute to the understanding of the carcinogenic effect of soil arsenic and nickel exposure in general population.

  14. Sex differences in heart rate variability during sleep following prenatal nicotine exposure in rat pups.

    PubMed

    Boychuk, Carie R; Fuller, David D; Hayward, Linda F

    2011-05-16

    The influence of both prenatal nicotine exposure (PNE; 6 mg/kg/day) and sex on heart rate (HR) regulation during sleep versus wakefulness was evaluated in 13, 16 and 26 day old rat pups. Pups were chronically instrumented at least 24 h before testing. On postnatal day 13 (P13), PNE males spent significantly more time in NREM sleep and demonstrated a greater drop in HR when transitioning from quiet wake to sleep compared to age and sex matched controls (-14±5 bpm versus -1±3 bpm, respectively). Heart rate variability (HRV) analysis indicated that this state-dependent drop in HR was primarily associated with a greater reduction in sympathovagal balance (LF/HF ratio) in PNE males compared to controls. No parallel changes in indices of parasympathetic drive (HF power) were identified. In contrast, no significant effect of PNE on HR during sleep versus wakefulness was identified in P13 females. However, independent of state, a significant decrease in HF power was identified in P13 PNE females compared to controls. At P16, state-dependent differences in HR or HRV between PNE and sex-matched control pups were resolved. Additionally, at P26 no significant effect of PNE on state-dependent changes in HR or HRV was identified in either sex. Analysis of the hypothalamic peptide orexin identified that PNE induced approximately a 50% reduction in hypothalamic prepro-orexin mRNA and total mRNA was lowest in PNE males. These findings suggest that PNE induces sex dependent changes in sleep related autonomic regulation of HR during early postnatal development and these changes may be related to epigenetic alterations in the orexin system.

  15. Exposure to Polycyclic Aromatic Hydrocarbons, Plasma Cytokines, and Heart Rate Variability.

    PubMed

    Yang, Binyao; Deng, Qifei; Zhang, Wangzhen; Feng, Yingying; Dai, Xiayun; Feng, Wei; He, Xiaosheng; Huang, Suli; Zhang, Xiao; Li, Xiaohai; Lin, Dafeng; He, Meian; Guo, Huan; Sun, Huizhen; Yuan, Jing; Lu, Jiachun; Hu, Frank B; Zhang, Xiaomin; Wu, Tangchun

    2016-01-01

    Epidemiological studies have suggested associations between polycyclic aromatic hydrocarbons (PAHs) and heart rate variability (HRV). However, the roles of plasma cytokines in these associations are limited. In discovery stage of this study, we used Human Cytokine Antibody Arrays to examine differences in the concentrations of 280 plasma cytokines between 8 coke-oven workers and 16 community residents. We identified 19 cytokines with significant different expression (fold change ≥2 or ≤-2, and q-value <5%) between exposed workers and controls. 4 cytokines were selected to validate in 489 coke-oven workers by enzyme-linked immunosorbent assays in validation stage. We found OH-PAHs were inversely associated with brain-derived neurotrophic factor (BDNF) (p < 0.05), and interquartile range (IQR) increases in OH-PAHs were associated with >16% BDNF decreases. Additionally, OH-PAHs were positively associated with activated leukocyte cell adhesion molecule (ALCAM) and C-reactive protein (CRP) (p < 0.05), and IQR increases in OH-PAHs were associated with >20% increases in CRP. We also found significant associations between these cytokines and HRV (p < 0.05), and IQR increases in BDNF and CRP were associated with >8% decreases in HRV. Our results indicated PAH exposure was associated with plasma cytokines, and higher cytokines were associated with decreased HRV, but additional human and potential mechanistic studies are needed. PMID:26758679

  16. Annual solar UV exposure and biological effective dose rates on the Martian surface

    NASA Astrophysics Data System (ADS)

    Patel, M. R.; Bérces, A.; Kerékgyárto, T.; Rontó, Gy.; Lammer, H.; Zarnecki, J. C.

    2004-01-01

    The ultraviolet (UV) environment of Mars has been investigated to gain an understanding of the variation of exposure throughout a Martian year, and link this flux to biological effects and possible survival of organisms at the Martian surface. To gain an idea of how the solar UV radiation varies between different regions, including planned landing sites of two future Mars surface missions, we modelled the total solar UV surface flux throughout one Martian year for two different dust scenarios. To understand the degree of solar UV stress on micro-organisms and/or molecules essential for life on the surface of Mars, we also calculated the biologically effective dose (BED) for T7 and Uracil in relevant wavelength regions at the Martian surface as a function of season and latitude, and discuss the biological survival rates in the presence of Martian solar UV radiation. High T7/Uracil BED ratios indicate that even at high latitudes where the UV flux is significantly reduced, the radiation environment is still hostile for life due to the persisting UV-C component of the flux.

  17. Exposure to Polycyclic Aromatic Hydrocarbons, Plasma Cytokines, and Heart Rate Variability

    PubMed Central

    Yang, Binyao; Deng, Qifei; Zhang, Wangzhen; Feng, Yingying; Dai, Xiayun; Feng, Wei; He, Xiaosheng; Huang, Suli; Zhang, Xiao; Li, Xiaohai; Lin, Dafeng; He, Meian; Guo, Huan; Sun, Huizhen; Yuan, Jing; Lu, Jiachun; Hu, Frank B.; Zhang, Xiaomin; Wu, Tangchun

    2016-01-01

    Epidemiological studies have suggested associations between polycyclic aromatic hydrocarbons (PAHs) and heart rate variability (HRV). However, the roles of plasma cytokines in these associations are limited. In discovery stage of this study, we used Human Cytokine Antibody Arrays to examine differences in the concentrations of 280 plasma cytokines between 8 coke-oven workers and 16 community residents. We identified 19 cytokines with significant different expression (fold change ≥2 or ≤−2, and q-value <5%) between exposed workers and controls. 4 cytokines were selected to validate in 489 coke-oven workers by enzyme-linked immunosorbent assays in validation stage. We found OH-PAHs were inversely associated with brain-derived neurotrophic factor (BDNF) (p < 0.05), and interquartile range (IQR) increases in OH-PAHs were associated with >16% BDNF decreases. Additionally, OH-PAHs were positively associated with activated leukocyte cell adhesion molecule (ALCAM) and C-reactive protein (CRP) (p < 0.05), and IQR increases in OH-PAHs were associated with >20% increases in CRP. We also found significant associations between these cytokines and HRV (p < 0.05), and IQR increases in BDNF and CRP were associated with >8% decreases in HRV. Our results indicated PAH exposure was associated with plasma cytokines, and higher cytokines were associated with decreased HRV, but additional human and potential mechanistic studies are needed. PMID:26758679

  18. Radio frequency electromagnetic field exposure in humans: Estimation of SAR distribution in the brain, effects on sleep and heart rate.

    PubMed

    Huber, Reto; Schuderer, Jürgen; Graf, Thomas; Jütz, Kathrin; Borbély, Alexander A; Kuster, Niels; Achermann, Peter

    2003-05-01

    In two previous studies we demonstrated that radiofrequency electromagnetic fields (RF EMF) similar to those emitted by digital radiotelephone handsets affect brain physiology of healthy young subjects exposed to RF EMF (900 MHz; spatial peak specific absorption rate [SAR] 1 W/kg) either during sleep or during the waking period preceding sleep. In the first experiment, subjects were exposed intermittently during an 8 h nighttime sleep episode and in the second experiment, unilaterally for 30 min prior to a 3 h daytime sleep episode. Here we report an extended analysis of the two studies as well as the detailed dosimetry of the brain areas, including the assessment of the exposure variability and uncertainties. The latter enabled a more in depth analysis and discussion of the findings. Compared to the control condition with sham exposure, spectral power of the non-rapid eye movement sleep electroencephalogram (EEG) was initially increased in the 9-14 Hz range in both experiments. No topographical differences with respect to the effect of RF EMF exposure were observed in the two experiments. Even unilateral exposure during waking induced a similar effect in both hemispheres. Exposure during sleep reduced waking after sleep onset and affected heart rate variability. Exposure prior to sleep reduced heart rate during waking and stage 1 sleep. The lack of asymmetries in the effects on sleep EEG, independent of bi- or unilateral exposure of the cortex, may indicate involvement of subcortical bilateral projections to the cortex in the generation of brain function changes, especially since the exposure of the thalamus was similar in both experiments (approx. 0.1 W/kg).

  19. The rate of protein synthesis in hematopoietic stem cells is limited partly by 4E-BPs

    PubMed Central

    Signer, Robert A.J.; Qi, Le; Zhao, Zhiyu; Thompson, David; Sigova, Alla A.; Fan, Zi Peng; DeMartino, George N.; Young, Richard A.; Sonenberg, Nahum; Morrison, Sean J.

    2016-01-01

    Adult stem cells must limit their rate of protein synthesis, but the underlying mechanisms remain largely unexplored. Differences in protein synthesis among hematopoietic stem cells (HSCs) and progenitor cells did not correlate with differences in proteasome activity, total RNA content, mRNA content, or cell division rate. However, adult HSCs had more hypophosphorylated eukaryotic initiation factor 4E-binding protein 1 (4E-BP1) and 4E-BP2 as compared with most other hematopoietic progenitors. Deficiency for 4E-BP1 and 4E-BP2 significantly increased global protein synthesis in HSCs, but not in other hematopoietic progenitors, and impaired their reconstituting activity, identifying a mechanism that promotes HSC maintenance by attenuating protein synthesis. PMID:27492367

  20. Advanced Computational Approaches for Characterizing Stochastic Cellular Responses to Low Dose, Low Dose Rate Exposures

    SciTech Connect

    Scott, Bobby, R., Ph.D.

    2003-06-27

    applications of NEOTRANS2, indicate that nonlinear threshold-type, dose-response relationships for excess stochastic effects (problematic nonlethal mutations, neoplastic transformation) should be expected after exposure to low linear energy transfer (LET) gamma rays or gamma rays in combination with high-LET alpha radiation. Similar thresholds are expected for low-dose-rate low-LET beta irradiation. We attribute the thresholds to low-dose, low-LET radiation induced protection against spontaneous mutations and neoplastic transformations. The protection is presumed mainly to involve selective elimination of problematic cells via apoptosis. Low-dose, low-LET radiation is presumed to trigger wide-area cell signaling, which in turn leads to problematic bystander cells (e.g., mutants, neoplastically transformed cells) selectively undergoing apoptosis. Thus, this protective bystander effect leads to selective elimination of problematic cells (a tissue cleansing process in vivo). However, this protective bystander effects is a different process from low-dose stimulation of the immune system. Low-dose, low-LET radiation stimulation of the immune system may explain why thresholds for inducing excess cancer appear much larger (possibly more than 100-fold larger) than thresholds for inducing excess mutations and neoplastic transformations, when the dose rate is low. For ionizing radiation, the current risk assessment paradigm is such that the relative risk (RR) is always ¡Ý 1, no matter how small the dose. Our research results indicate that for low-dose or low-dose-rate, low-LET irradiation, RR < 1 may be more the rule than the exception. Directly tied to the current RR paradigm are the billion-dollar cleanup costs for radionuclide-contaminated DOE sites. Our research results suggest that continued use of the current RR paradigm for which RR ¡Ý 1 could cause more harm than benefit to society (e.g., by spreading unwarranted fear about phantom excess risks associated with low-dose low

  1. Effects of acute fresh water exposure on water flux rates and osmotic responses in Kemp's ridley sea turtles (Lepidochelys kempi)

    NASA Technical Reports Server (NTRS)

    Ortiz, R. M.; Patterson, R. M.; Wade, C. E.; Byers, F. M.

    2000-01-01

    Water flux rates and osmotic responses of Kemp's Ridley sea turtles (Lepidochelys kempi) acutely exposed to fresh water were quantified. Salt-water adapted turtles were exposed to fresh water for 4 d before being returned to salt water. During the initial salt water phase, absolute and relative water flux rates were 1.2+/-0.1 l d(-1) and 123.0+/-6.8 ml kg(-1) d(-1), respectively. When turtles were exposed to fresh water, rates increased by approximately 30%. Upon return to salt water, rates decreased to original levels. Plasma osmolality, Na(+), K(+), and Cl(-) decreased during exposure to fresh water, and subsequently increased during the return to salt water. The Na(+):K(+) ratio was elevated during the fresh water phase and subsequently decreased upon return to salt water. Aldosterone and corticosterone were not altered during exposure to fresh water. Elevated water flux rates during fresh water exposure reflected an increase in water consumption, resulting in a decrease in ionic and osmotic concentrations. The lack of a change in adrenocorticoids to acute fresh water exposure suggests that adrenal responsiveness to an hypo-osmotic environment may be delayed in marine turtles when compared to marine mammals.

  2. Effects of acute fresh water exposure on water flux rates and osmotic responses in Kemp's ridley sea turtles (Lepidochelys kempi).

    PubMed

    Ortiz, R M; Patterson, R M; Wade, C E; Byers, F M

    2000-09-01

    Water flux rates and osmotic responses of Kemp's Ridley sea turtles (Lepidochelys kempi) acutely exposed to fresh water were quantified. Salt-water adapted turtles were exposed to fresh water for 4 d before being returned to salt water. During the initial salt water phase, absolute and relative water flux rates were 1.2+/-0.1 l d(-1) and 123.0+/-6.8 ml kg(-1) d(-1), respectively. When turtles were exposed to fresh water, rates increased by approximately 30%. Upon return to salt water, rates decreased to original levels. Plasma osmolality, Na(+), K(+), and Cl(-) decreased during exposure to fresh water, and subsequently increased during the return to salt water. The Na(+):K(+) ratio was elevated during the fresh water phase and subsequently decreased upon return to salt water. Aldosterone and corticosterone were not altered during exposure to fresh water. Elevated water flux rates during fresh water exposure reflected an increase in water consumption, resulting in a decrease in ionic and osmotic concentrations. The lack of a change in adrenocorticoids to acute fresh water exposure suggests that adrenal responsiveness to an hypo-osmotic environment may be delayed in marine turtles when compared to marine mammals.

  3. ALGORITHMS FOR ESTIMATING RESTING METABOLIC RATE AND ACTIVITY SPECIFIC VENTILATION RATES FOR USE IN COMPLEX EXPOSURE AND INTAKE DOSE MODELS

    EPA Science Inventory

    This work summarizes advancements made that allow for better estimation of resting metabolic rate (RMR) and subsequent estimation of ventilation rates (i.e., total ventilation (VE) and alveolar ventilation (VA)) for individuals of both genders and all ages. ...

  4. Exposure to Sexist Humor and Rape Proclivity: The Moderator Effect of Aversiveness Ratings

    ERIC Educational Resources Information Center

    Romero-Sanchez, Monica; Duran, Mercedes; Carretero-Dios, Hugo; Megias, Jesus L.; Moya, Miguel

    2010-01-01

    The aim of this study is to explore the effect of exposure to sexist humor about women on men's self-reported rape proclivity. Earlier studies have shown that exposure to this type of humor increases rape proclivity and that funniness responses to jokes are a key element to consider. However, the role of aversiveness responses has not been…

  5. Revisiting Print Exposure: Exploring Differential Links to Vocabulary, Comprehension and Reading Rate

    ERIC Educational Resources Information Center

    Martin-Chang, Sandra Lyn; Gould, Odette N.

    2008-01-01

    Undergraduates (N = 171) completed a revised version of the Author Recognition Test (Stanovich & West, 1989). The resulting print exposure scores were divided into two dimensions: personal reading experience (primary print knowledge--PPK) and secondary print knowledge (SPK). Both PPK and SPK were correlated with print exposure, but not with each…

  6. Altered turnover and synthesis rates of lung surfactant following thoracic irradiation

    SciTech Connect

    Coultas, P.G.; Ahier, R.G.; Anderson, R.L.

    1987-02-01

    Between 2-6 weeks after thoracic irradiation with 10 Gy X rays, when levels of surfactant in the alveoli show the greatest increase, there is a reduction in the rate of radioactivity loss from /sup 3/H-choline labeled disaturated phosphatidylcholine from the lung. This indicates a reduced turnover of surfactant. Discrepancies between the halving times for specific activity and for total radioactivity of the disaturated phospholipids suggest that at between 2 and 3 weeks post-irradiation, removal and degradation of surfactant almost ceases, but that synthesis continues normally. However, by 3 weeks post-irradiation, choline-/sup 3/H incorporation into disaturated phosphatidylcholine suggests that surfactant synthesis is increased about two-fold. The reduced number of macrophages recovered from alveolar lavage between about 2 and 6 weeks post-irradiation may indicate a reason for the lengthened turnover times of surfactant over this period. Nevertheless, the stimulated surfactant production that takes place from about 3 weeks onward suggests an additional active response to radiation or to radiation damage by the type II pneumonocytes. These studies confirm that the maximum levels of alveolar surfactant seen at 3 weeks post-irradiation result from a different lung response than that responsible for the increase in surfactant, which occurs within hours of irradiation.

  7. Glutamine supplementation does not improve protein synthesis rate by the jejunal mucosa of the malnourished rat.

    PubMed

    Tannus, Andrea Ferreira S; Darmaun, Dominique; Ribas, Durval F; Oliveira, José Eduardo D; Marchini, Julio Sergio

    2009-08-01

    It has been demonstrated that glutamine, a conditionally essential amino acid, improves nitrogen balance, acts as a stimulant of protein synthesis, and decreases proteolysis in myopathic children. In contrast, other studies have shown no beneficial effect of glutamine supplementation on burn victims or critically ill patients. Nonetheless, we hypothesized that glutamine supplementation would increase the fractional protein synthesis rate (FSR) in the jejunal mucosa of malnourished male Wistar rats. Thus, the objective of the present study was to test the effect of daily oral glutamine supplementation (0.42 g kg(-1) d(-1) for 14 days) on the FSR of the jejunal mucosa of healthy and malnourished rats. A 4-hour kinetic study with l-[1-(13)C]leucine was subsequently performed, and jejunal biopsies were obtained 1.5 cm from the Treitz angle and analyzed. Malnourished rats showed a 25% weight loss and increased urinary nitrogen excretion. Plasma amino acid concentration did not differ between groups. (13)C enrichment in plasma and jejunal cells was higher in the malnourished groups than in the healthy group. The FSR (percent per hour) was similar for the control and experimental groups (P > .05), with a mean range of 22%/h to 27%/h. Oral glutamine supplementation alone did not induce higher protein incorporation by the jejunal mucosa in malnourished rats, regardless of total food intake or the presence or absence of glutamine supplementation.

  8. Development and Evaluation of a New Air Exchange Rate Algorithm for the Stochastic Human Exposure and Dose Simulation Model (ISES Presentation)

    EPA Science Inventory

    Previous exposure assessment panel studies have observed considerable seasonal, between-home and between-city variability in residential pollutant infiltration. This is likely a result of differences in home ventilation, or air exchange rates (AER). The Stochastic Human Exposure ...

  9. Probabilistic exposure assessment model to estimate aseptic-UHT product failure rate.

    PubMed

    Pujol, Laure; Albert, Isabelle; Magras, Catherine; Johnson, Nicholas Brian; Membré, Jeanne-Marie

    2015-01-01

    Aseptic-Ultra-High-Temperature (UHT) products are manufactured to be free of microorganisms capable of growing in the food at normal non-refrigerated conditions at which the food is likely to be held during manufacture, distribution and storage. Two important phases within the process are widely recognised as critical in controlling microbial contamination: the sterilisation steps and the following aseptic steps. Of the microbial hazards, the pathogen spore formers Clostridium botulinum and Bacillus cereus are deemed the most pertinent to be controlled. In addition, due to a relatively high thermal resistance, Geobacillus stearothermophilus spores are considered a concern for spoilage of low acid aseptic-UHT products. A probabilistic exposure assessment model has been developed in order to assess the aseptic-UHT product failure rate associated with these three bacteria. It was a Modular Process Risk Model, based on nine modules. They described: i) the microbial contamination introduced by the raw materials, either from the product (i.e. milk, cocoa and dextrose powders and water) or the packaging (i.e. bottle and sealing component), ii) the sterilisation processes, of either the product or the packaging material, iii) the possible recontamination during subsequent processing of both product and packaging. The Sterility Failure Rate (SFR) was defined as the sum of bottles contaminated for each batch, divided by the total number of bottles produced per process line run (10(6) batches simulated per process line). The SFR associated with the three bacteria was estimated at the last step of the process (i.e. after Module 9) but also after each module, allowing for the identification of modules, and responsible contamination pathways, with higher or lower intermediate SFR. The model contained 42 controlled settings associated with factory environment, process line or product formulation, and more than 55 probabilistic inputs corresponding to inputs with variability

  10. Probabilistic exposure assessment model to estimate aseptic-UHT product failure rate.

    PubMed

    Pujol, Laure; Albert, Isabelle; Magras, Catherine; Johnson, Nicholas Brian; Membré, Jeanne-Marie

    2015-01-01

    Aseptic-Ultra-High-Temperature (UHT) products are manufactured to be free of microorganisms capable of growing in the food at normal non-refrigerated conditions at which the food is likely to be held during manufacture, distribution and storage. Two important phases within the process are widely recognised as critical in controlling microbial contamination: the sterilisation steps and the following aseptic steps. Of the microbial hazards, the pathogen spore formers Clostridium botulinum and Bacillus cereus are deemed the most pertinent to be controlled. In addition, due to a relatively high thermal resistance, Geobacillus stearothermophilus spores are considered a concern for spoilage of low acid aseptic-UHT products. A probabilistic exposure assessment model has been developed in order to assess the aseptic-UHT product failure rate associated with these three bacteria. It was a Modular Process Risk Model, based on nine modules. They described: i) the microbial contamination introduced by the raw materials, either from the product (i.e. milk, cocoa and dextrose powders and water) or the packaging (i.e. bottle and sealing component), ii) the sterilisation processes, of either the product or the packaging material, iii) the possible recontamination during subsequent processing of both product and packaging. The Sterility Failure Rate (SFR) was defined as the sum of bottles contaminated for each batch, divided by the total number of bottles produced per process line run (10(6) batches simulated per process line). The SFR associated with the three bacteria was estimated at the last step of the process (i.e. after Module 9) but also after each module, allowing for the identification of modules, and responsible contamination pathways, with higher or lower intermediate SFR. The model contained 42 controlled settings associated with factory environment, process line or product formulation, and more than 55 probabilistic inputs corresponding to inputs with variability

  11. Recovery of photosynthesis and growth rate in green, blue-green, and diatom algae after exposure to atrazine.

    PubMed

    Brain, Richard A; Arnie, Joshua R; Porch, John R; Hosmer, Alan J

    2012-11-01

    We evaluated the recovery of photosynthesis and growth rate in green (Pseudokirchneriella subcapitata), blue-green (Anabaena flos-aquae), and diatom (Navicula pelliculosa) algae after pulsed exposure to atrazine. Subsequent to a grow-up period of 24 to 72 h to establish requisite cell density for adequate signal strength to measure photosystem II (PSII) quantum yield, algae were exposed to a pulse of atrazine for 48 h followed by a 48-h recovery period in control media. Photosynthesis was measured at 0, 3, 6, 12, 24, and 48 h of the exposure and recovery phases using pulse amplitude modulation fluorometry; growth rate and cell density were also concomitantly measured at these time points. Exposure to atrazine resulted in immediate, but temporary, inhibition of photosynthesis and growth; however, these effects were transient and fully reversible in the tested species of algae. For all three algal species, no statistically significant reductions (p ≤ 0.05) in growth rate or PSII quantum yield were detected at any of the treatment concentrations 48 h after atrazine was removed from the test system. Effects at test levels up to the highest tested exposure levels were consequently determined to be algistatic (reversible). Both biochemically and physiologically, recovery of photosynthesis and growth rate occur immediately, reaching control levels within hours following exposure. Therefore, pulsed exposure profiles of atrazine typically measured in Midwestern U.S. streams are unlikely to result in biologically meaningful changes in primary production given that the effects of atrazine are temporary and fully reversible in species representative of native populations.

  12. Development of the town data base: Estimates of exposure rates and times of fallout arrival near the Nevada Test Site

    SciTech Connect

    Thompson, C.B.; McArthur, R.D.; Hutchinson, S.W.

    1994-09-01

    As part of the U.S. Department of Energy`s Off-Site Radiation Exposure Review Project, the time of fallout arrival and the H+12 exposure rate were estimated for populated locations in Arizona, California, Nevada, and Utah that were affected by fallout from one or more nuclear tests at the Nevada Test Site. Estimates of exposure rate were derived from measured values recorded before and after each test by fallout monitors in the field. The estimate for a given location was obtained by retrieving from a data base all measurements made in the vicinity, decay-correcting them to H+12, and calculating an average. Estimates were also derived from maps produced after most events that show isopleths of exposure rate and time of fallout arrival. Both sets of isopleths on these maps were digitized, and kriging was used to interpolate values at the nodes of a 10-km grid covering the pattern. The values at any location within the grid were then estimated from the values at the surrounding grid nodes. Estimates of dispersion (standard deviation) were also calculated. The Town Data Base contains the estimates for all combinations of location and nuclear event for which the estimated mean H+12 exposure rate was greater than three times background. A listing of the data base is included as an appendix. The information was used by other project task groups to estimate the radiation dose that off-site populations and individuals may have received as a result of exposure to fallout from Nevada nuclear tests.

  13. Estimated effective dose rates from radon exposure in workplaces and residences within Los Alamos county in New Mexico

    SciTech Connect

    Whicker, Jeffrey J; Mcnaughton, Michael

    2009-01-01

    Many millions of office workers are exposed to radon while at work and at home. Though there has been a multitude of studies reporting the measurements of radon concentrations and potential lung and effective doses associated with radon and progeny exposure in homes, similar studies on the concentrations and subsequent effective dose rates in the workplace are lacking. The purposes of this study were to measure radon concentrations in office and residential spaces in the same county and explore the radiation dose implications. Sixty-five track-etch detectors were deployed in office spaces and 47 were deployed in residences, all within Los Alamos County, New Mexico, USA. The sampling periods for these measurements were generally about three months. The measured concentrations were then used to calculate and compare effective dose rates resulting from exposure while at work and at home. Results showed that full-time office workers receive on average about nine times greater exposure at home than while in the office (691 mrem yr{sup -1} versus 78 mrem yr{sup -1}). The estimated effective dose rate for a more homebound person was 896 mrem yr{sup -1}. These effective dose rates are contrasted against the 100 mrem yr{sup -1} threshold for regulation of a 'radiological worker' defined in the Department of Energy regulations occupational exposure and the 10 mrem yr{sup -1} air pathway effective public dose limit regulated by the Environmental Protection Agency.

  14. Increasing the Homogeneity of CAT's Item-Exposure Rates by Minimizing or Maximizing Varied Target Functions while Assembling Shadow Tests

    ERIC Educational Resources Information Center

    Li, Yuan H.; Schafer, William D.

    2005-01-01

    A computerized adaptive testing (CAT) algorithm that has the potential to increase the homogeneity of CAT's item-exposure rates without significantly sacrificing the precision of ability estimates was proposed and assessed in the shadow-test (van der Linden & Reese, 1998) CAT context. This CAT algorithm was formed by a combination of maximizing or…

  15. Synthesis of fatty acid ethyl esters in mammalian tissues after ethanol exposure: a systematic review of the literature.

    PubMed

    Zelner, Irene; Matlow, Jeremy N; Natekar, Aniket; Koren, Gideon

    2013-08-01

    The ability to undergo non-oxidative metabolism from ethanol to fatty acid ethyl esters (FAEEs) varies greatly among tissues and organs. To gain a greater understanding of non-oxidative ethanol metabolism to FAEE, we aimed to collect all published data on FAEE synthesis in mammalian organs and tissues to identify all tissues, organs, and enzymes that are known to, or likely possess FAEE-synthetic activity. A systematic search for relevant papers was performed and two independent reviewers examined potentially relevant abstracts (articles on FAEEs that pertain to ethanol exposure) to determine whether they met the inclusion criteria. Information on FAEE synthesis was retrieved from papers meeting the inclusion/exclusion criteria and summarized by organ/tissue/matrix examined. The systematic search through four databases yielded 78 articles that investigated FAEE synthesis by tissues, tissue fractions and cell lines, and 29 articles that attempted to purify and/or characterize the enzymes involved in FAEE synthesis. Two enzyme activities have been studied: FAEE synthase (FAEES, which conjugates ethanol and free fatty acid) and acyl-CoA: ethanol O-acyltransferase (AEAT, which conjugates ethanol and fatty acyl-CoA). Both activities are expressed by a variety of different enzymes. FAEES activity is the most widely studied and has been purified from several tissues and shown to be associated with several well-known enzymes, while the identity of enzymes possessing AEAT activity remains unknown. The organs and tissues that have been shown to synthesize FAEEs are discussed, with special emphasis on the studies that attempted to elucidate the enzymology of FAEE synthesis in those tissues.

  16. Synthesis of fatty acid ethyl esters in mammalian tissues after ethanol exposure: a systematic review of the literature.

    PubMed

    Zelner, Irene; Matlow, Jeremy N; Natekar, Aniket; Koren, Gideon

    2013-08-01

    The ability to undergo non-oxidative metabolism from ethanol to fatty acid ethyl esters (FAEEs) varies greatly among tissues and organs. To gain a greater understanding of non-oxidative ethanol metabolism to FAEE, we aimed to collect all published data on FAEE synthesis in mammalian organs and tissues to identify all tissues, organs, and enzymes that are known to, or likely possess FAEE-synthetic activity. A systematic search for relevant papers was performed and two independent reviewers examined potentially relevant abstracts (articles on FAEEs that pertain to ethanol exposure) to determine whether they met the inclusion criteria. Information on FAEE synthesis was retrieved from papers meeting the inclusion/exclusion criteria and summarized by organ/tissue/matrix examined. The systematic search through four databases yielded 78 articles that investigated FAEE synthesis by tissues, tissue fractions and cell lines, and 29 articles that attempted to purify and/or characterize the enzymes involved in FAEE synthesis. Two enzyme activities have been studied: FAEE synthase (FAEES, which conjugates ethanol and free fatty acid) and acyl-CoA: ethanol O-acyltransferase (AEAT, which conjugates ethanol and fatty acyl-CoA). Both activities are expressed by a variety of different enzymes. FAEES activity is the most widely studied and has been purified from several tissues and shown to be associated with several well-known enzymes, while the identity of enzymes possessing AEAT activity remains unknown. The organs and tissues that have been shown to synthesize FAEEs are discussed, with special emphasis on the studies that attempted to elucidate the enzymology of FAEE synthesis in those tissues. PMID:23713893

  17. A quantitative autoradiographic method for the measurement of local rates of brain protein synthesis

    SciTech Connect

    Dwyer, B.E.; Donatoni, P.; Wasterlain, C.G.

    1982-05-01

    We have developed a new method for measuring local rates of brain protein synthesis in vivo. It combines the intraperitoneal injection of a large dose of low specific activity amino acid with quantitative autoradiography. This method has several advantages: 1) It is ideally suited for young or small animals or where immobilizing an animal is undesirable. 2 The amino acid injection ''floods'' amino acid pools so that errors in estimating precursor specific activity, which is especially important in pathological conditions, are minimized. 3) The method provides for the use of a radioautographic internal standard in which valine incorporation is measured directly. Internal standards from experimental animals correct for tissue protein content and self-absorption of radiation in tissue sections which could vary under experimental conditions.

  18. Measuring DNA synthesis rates with [1-13C]glycine.

    PubMed

    Chen, P; Abramson, F P

    1998-05-01

    We have devised and evaluated a stable-isotopic method for measuring DNA synthesis rates. The probe is [1-13C]-glycine that is incorporated into purines via de novo biosynthesis. The human hepatoma cell line HEP G2 was grown in medium containing [1-13C]glycine, the cells were harvested at various times, and the DNA was extracted. Following hydrolysis to the nucleosides, a reversed-phase HPLC separation was used to provide separate peaks for deoxythymidine (dT), deoxyadenosine (dA), and deoxyguanosine (dG). The HPLC effluent was continuously fed into a chemical reaction interface and an isotope ratio mass spectrometer (HPLC/CRI/IRMS). The isotope ratio of the CO2 produced in the CRI was used to monitor for enrichment. The cells were grown continuously for 5 days in labeled medium and also in a 1-day pulse labeling experiment where the washout of label was observed for the subsequent 9 days. As predicted from the role of glycine in de novo purine biosynthesis, the isotope ratio of the pyrimidine dT did not change. However, for the two purines, dA and dG, the characteristic log growth behavior of the cells was observed in their 13C/12C ratios and good agreement in the doubling time was obtained for each type of experiment. Parallel experiments that measured the HEP G2 doubling time in culture using tritiated thymidine incorporation and direct cell counts were carried out compare to our new method with established ones. We believe that the use of [1-13C]-glycine and the HPLC/CRI/IRMS is a highly sensitive and selective approach that forms the basis of a method that can measure DNA synthesis rates using a nonradioactive, nontoxic tracer. PMID:9599574

  19. ESTIMATED RATE OF FATAL AUTOMOBILE ACCIDENTS ATTRIBUTABLE TO ACUTE SOLVENT EXPOSURE AT LOW INHALED CONCENTRATIONS

    EPA Science Inventory

    Acute solvent exposures may contribute to automobile accidents because they increase reaction time and decrease attention, in addition to impairing other behaviors. These effects resemble those of ethanol consumption, both with respect to behavioral effects and neurological mecha...

  20. Lead exposure and recovery rates of black ducks banded in Tennessee

    USGS Publications Warehouse

    Samuel, Michael D.; Bowers, E. Frank; Franson, J. Christian

    1992-01-01

    American black ducks (Anas rubripes) wintering in Tennessee during 1986 to 1988 were tested for exposure to lead. Twelve percent of the birds had blood lead concentrations exceeding 0.2 ppm. Significant differences in the prevalence of lead exposure were found for adults (14.4%) and juveniles (8.2%). Exposed birds had higher blood lead concentrations at one study site, corresponding with a lower survival index.

  1. Deducing the Kinetics of Protein Synthesis In Vivo from the Transition Rates Measured In Vitro

    PubMed Central

    Rudorf, Sophia; Thommen, Michael; Rodnina, Marina V.; Lipowsky, Reinhard

    2014-01-01

    The molecular machinery of life relies on complex multistep processes that involve numerous individual transitions, such as molecular association and dissociation steps, chemical reactions, and mechanical movements. The corresponding transition rates can be typically measured in vitro but not in vivo. Here, we develop a general method to deduce the in-vivo rates from their in-vitro values. The method has two basic components. First, we introduce the kinetic distance, a new concept by which we can quantitatively compare the kinetics of a multistep process in different environments. The kinetic distance depends logarithmically on the transition rates and can be interpreted in terms of the underlying free energy barriers. Second, we minimize the kinetic distance between the in-vitro and the in-vivo process, imposing the constraint that the deduced rates reproduce a known global property such as the overall in-vivo speed. In order to demonstrate the predictive power of our method, we apply it to protein synthesis by ribosomes, a key process of gene expression. We describe the latter process by a codon-specific Markov model with three reaction pathways, corresponding to the initial binding of cognate, near-cognate, and non-cognate tRNA, for which we determine all individual transition rates in vitro. We then predict the in-vivo rates by the constrained minimization procedure and validate these rates by three independent sets of in-vivo data, obtained for codon-dependent translation speeds, codon-specific translation dynamics, and missense error frequencies. In all cases, we find good agreement between theory and experiment without adjusting any fit parameter. The deduced in-vivo rates lead to smaller error frequencies than the known in-vitro rates, primarily by an improved initial selection of tRNA. The method introduced here is relatively simple from a computational point of view and can be applied to any biomolecular process, for which we have detailed information

  2. Reduction in diarrheal rates through interventions that prevent unnecessary antibiotic exposure early in life in an observational birth cohort

    PubMed Central

    Rogawski, Elizabeth T.; Meshnick, Steven R.; Becker-Dreps, Sylvia; Adair, Linda S.; Sandler, Robert S.; Sarkar, Rajiv; Kattula, Deepthi; Ward, Honorine D.; Kang, Gagandeep; Westreich, Daniel J.

    2016-01-01

    Background Antibiotic treatment early in life is often not needed and has been associated with increased rates of subsequent diarrhea. We estimated the impact of realistic interventions, which would prevent unnecessary antibiotic exposures before 6 months of age, on reducing childhood diarrheal rates. Methods In data from a prospective observational cohort study conducted in Vellore, India, we used the parametric g-formula to model diarrheal incidence rate differences contrasting the observed incidence of diarrhea to the incidence expected under hypothetical interventions. The interventions prevented unnecessary antibiotic treatments for non-bloody diarrhea, vomiting, and upper respiratory infections before 6 months of age. We also modeled targeted interventions, in which unnecessary antibiotic use was prevented only among children who had already stopped exclusive breastfeeding. Results More than half of all antibiotic exposures before 6 months (58.9%) were likely unnecessary. The incidence rate difference associated with removing unnecessary antibiotic use before 6 months of age was -0.28 (95% confidence interval: -0.46, -0.08) episodes per 30 child-months. This implies that preventing unnecessary antibiotic exposures in just 4 children would reduce the incidence of diarrhea by one from 6 months to 3 years of age. Conclusions Interventions to reduce unnecessary antibiotic use among young children could result in an important reduction in diarrheal rates. This work provides an example application of statistical methods which can further the aim of presenting epidemiologic findings that are relevant to public health practice. PMID:26621194

  3. Life span of C57 mice as influenced by radiation dose, dose rate, and age at exposure

    SciTech Connect

    Spalding, J.F.; Thomas, R.G.; Tietjen, G.L.

    1982-10-01

    This study was designed to measure the life shortening of C57BL/6J male mice as a result of exposure to five external doses from /sup 60/Co gamma radiation delivered at six different dose rates. Total doses ranged from 20 to 1620 rad at exposure rates ranging from 0.7 to 36,000 R/day. The ages of the mice at exposure were newborn, 2, 6, or 15 months. Two replications were completed. Although death was the primary endpoint, we did perform gross necropsies. The life span findings are variable, but we found no consistent shortening compared to control life spans. Therefore, we cannot logically extrapolate life shortening to lower doses, from the data we have obtained. In general, the younger the animals were at the beginning of exposure, the longer their life spans were compared to those of controls. This relationship weakened at the higher doses and dose rates, as mice in these categories tended not to have significantly different life spans from controls. Using life span as a criterion, we find this study suggests that some threshold dosage may exist beyond which effects of external irradiation may be manifested. Up to this threshold, there is no shortening effect on life span compared to that of control mice. Our results are in general agreement with the results of other researchers investigating human and other animal life span effects on irradiation.

  4. Two Mechanisms: The Role of Social Capital and Industrial Pollution Exposure in Explaining Racial Disparities in Self-Rated Health

    PubMed Central

    Ard, Kerry; Colen, Cynthia; Becerra, Marisol; Velez, Thelma

    2016-01-01

    This study provides an empirical test of two mechanisms (social capital and exposure to air pollution) that are theorized to mediate the effect of neighborhood on health and contribute to racial disparities in health outcomes. To this end, we utilize the Social Capital Benchmark Study, a national survey of individuals nested within communities in the United States, to estimate how multiple dimensions of social capital and exposure to air pollution, explain racial disparities in self-rated health. Our main findings show that when controlling for individual-confounders, and nesting within communities, our indicator of cognitive bridging, generalized trust, decreases the gap in self-rated health between African Americans and Whites by 84%, and the gap between Hispanics and Whites by 54%. Our other indicator of cognitive social capital, cognitive linking as represented by engagement in politics, decreases the gap in health between Hispanics and Whites by 32%, but has little impact on African Americans. We also assessed whether the gap in health was explained by respondents’ estimated exposure to toxicity-weighted air pollutants from large industrial facilities over the previous year. Our results show that accounting for exposure to these toxins has no effect on the racial gap in self-rated health in these data. This paper contributes to the neighborhood effects literature by examining the impact that estimated annual industrial air pollution, and multiple measures of social capital, have on explaining the racial gap in health in a sample of individuals nested within communities across the United States. PMID:27775582

  5. Effects of limited exposure of rabbit chondrocyte cultures to parathyroid hormone and dibutyryl adenosine 3',5'-monophosphate on cartilage-characteristic proteoglycan synthesis

    SciTech Connect

    Kato, Y.; Koike, T.; Iwamoto, M.; Kinoshita, M.; Sato, K.; Hiraki, Y.; Suzuki, F.

    1988-05-01

    Treatment of rabbit chondrocyte cultures with PTH or (Bu)2cAMP for 30 h increased by 2- to 3-fold the incorporation of (35S)sulfate and 3H radioactivity with glucosamine as the precursor into large chondroitin sulfate proteoglycans characteristically found in cartilage matrix. However, PTH and (Bu)2cAMP did not increase either (35S)sulfate incorporation into small proteoglycans or the incorporation of 3H radioactivity into hyaluronic acid and other glycosaminoglycans. PTH and (Bu)2cAMP also increased the incorporation of (3H) serine into both proteoglycans and total protein. In all cultures described above, the stimulation of (3H)serine incorporation into proteoglycans exceeded that of (3H)serine incorporation into total protein. These data indicate that PTH and (Bu)2cAMP selectively stimulate cartilage proteoglycan synthesis while they increase total protein synthesis. Since cAMP seems to play a mediatory role in the action of PTH, we elected to examine the effects of a limited exposure of chondrocytes to PTH or (Bu)2cAMP on the synthesis of proteoglycans. Treatment with PTH or (Bu)2cAMP for only the initial 2-7 h did not increase the rates of incorporation of (35S)sulfate, the 3H radioactivity with glucosamine, and (3H)serine into proteoglycans, as measured at 30 h, despite the fact that this treatment brought about a rapid and transient rise in the cAMP level. Furthermore, the application of prostaglandin I2 at concentrations that increased cAMP levels in a similar fashion as did PTH did not affect (35S) sulfate incorporation into proteoglycans.

  6. Impact of Heating Rate During Exposure of Laser Molten Parts on the Processing Window of PA12 Powder

    NASA Astrophysics Data System (ADS)

    Drummer, Dietmar; Drexler, Maximilian; Wudy, Katrin

    The additive component manufacturing by selective beam melting of thermoplastic polymer powders can be divided essentially into the following sub-processes: Powder coating, exposure and material consolidation. The mechanical and geometrical properties of a part produced by the selective melting of polymer powders depend toa large extent on these sub-processes. To increase process repeatability basic knowledge about the mutual interactions within the sub-process is of major interest. In the following article the exposure process is focused. Therefore the time dependent energy input into the powder bed is analyzed in its impact on the usable processing window of PA12powder. Thereby parameters like surface temperature, density and strength of molten layers as well as complex body specimens are quantified for varying exposure heating rates. Therefore methods of statistical design of experiments are used. Due to these investigations the derivation of new, the time dependent material behavior of polymers fitting processing strategies is possible.

  7. The role of compartment-specific cysteine synthesis for sulfur homeostasis during H2S exposure in Arabidopsis.

    PubMed

    Birke, Hannah; De Kok, Luit J; Wirtz, Markus; Hell, Rüdiger

    2015-02-01

    Sulfide is the end-product of assimilatory sulfate reduction in chloroplasts. It is then used by O-acetylserine(thiol)lyase (OAS-TL) to produce cysteine, the source of reduced sulfur in plants. While its formation in chloroplasts is essential for plant metabolism, sulfide is also a potent toxin mainly targeting respiration in mitochondria. Here, the application of sublethal concentrations of sulfide to Arabidopsis thaliana was used to by-pass assimilatory sulfate reduction, resulting in down-regulation of most genes of the pathway. The dualism of sulfide as substrate and toxin was investigated using knock-out mutants of the chloroplast-, mitochondrion- and cytosol-targeted OAS-TL isoforms. Surprisingly, growth retardation due to intoxication by sulfide was independent of the presence or absence of the three OAS-TL isoforms, indicating rapid exchange towards sulfur homoeostasis between the compartments. Cysteine, glutathione and sulfate, and less so S-sulfocysteine, were identified as major sinks for excess sulfide in wild-type plants. Additionally, the concentration of thiosulfate increased 1,000-fold, pointing towards a significant function of thiosulfate formation during H2S exposure. Synthesis of cysteine in the cytosol was found to be particularly important for accumulation of sulfite, sulfate and thiosulfate, indicating an important role for cytosolic OAS-TL for the re-oxidation of sulfide. The results show that thiosulfate and sulfate accumulation is strongly linked to cytosolic cysteine synthesis and that scavenging of sulfide by cysteine synthesis enhances sulfur compound accumulation. However, lack of cysteine synthesis in a subcellular compartment has no crucial consequences for toxicity and subsequent growth retardation.

  8. Laser-induced synthesis and decay of Tritium under exposure of solid targets in heavy water

    NASA Astrophysics Data System (ADS)

    Barmina, E. V.; Timashev, S. F.; Shafeev, G. A.

    2016-03-01

    The processes of laser-assisted synthesis of Tritium nuclei and their laser-induced decay in cold plasma in the vicinity of solid targets (Au, Ti, Se, etc.) immersed into heavy water are experimentally realized at peak laser intensity of 1010-1013 W/cm2. Initial stages of Tritium synthesis and their laser-induced beta-decay are interpreted on the basis of non-elastic interaction of plasma electrons having kinetic energy of 5-10 eV with nuclei of Deuterium and Tritium, respectively.

  9. Unscheduled DNA synthesis in human hair follicles after in vitro exposure to 11 chemicals: comparison with unscheduled DNA synthesis in rat hepatocytes.

    PubMed

    van Erp, Y H; Koopmans, M J; Heirbaut, P R; van der Hoeven, J C; Weterings, P J

    1992-06-01

    A new method is described to investigate unscheduled DNA synthesis (UDS) in human tissue after exposure in vitro: the human hair follicle. A histological technique was applied to assess cytotoxicity and UDS in the same hair follicle cells. UDS induction was examined for 11 chemicals and the results were compared with literature findings for UDS in rat hepatocytes. Most chemicals inducing UDS in rat hepatocytes raised DNA repair at comparable concentrations in the hair follicle. However, 1 of 9 chemicals that gave a positive response in the rat hepatocyte UDS test, 2-acetylaminofluorene, failed to induce DNA repair in the hair follicle. Metabolizing potential of hair follicle cells was shown in experiments with indirectly acting compounds, i.e., benzo[a]pyrene, 7,12-dimethylbenz[a]anthracene and dimethylnitrosamine. The results support the conclusion that the test in its present state is valuable as a screening assay for the detection of unscheduled DNA synthesis. Moreover, the use of human tissues may result in a better extrapolation to man.

  10. Exposure to particulate matter in India: A synthesis of findings and future directions.

    PubMed

    Pant, Pallavi; Guttikunda, Sarath K; Peltier, Richard E

    2016-05-01

    Air pollution poses a critical threat to human health with ambient and household air pollution identified as key health risks in India. While there are many studies investigating concentration, composition, and health effects of air pollution, investigators are only beginning to focus on estimating or measuring personal exposure. Further, the relevance of exposures studies from the developed countries in developing countries is uncertain. This review summarizes existing research on exposure to particulate matter (PM) in India, identifies gaps and offers recommendations for future research. There are a limited number of studies focused on exposure to PM and/or associated health effects in India, but it is evident that levels of exposure are much higher than those reported in developed countries. Most studies have focused on coarse aerosols, with a few studies on fine aerosols. Additionally, most studies have focused on a handful of cities, and there are many unknowns in terms of ambient levels of PM as well as personal exposure. Given the high mortality burden associated with air pollution exposure in India, a deeper understanding of ambient pollutant levels as well as source strengths is crucial, both in urban and rural areas. Further, the attention needs to expand beyond the handful large cities that have been studied in detail. PMID:26974362

  11. Exposure to particulate matter in India: A synthesis of findings and future directions.

    PubMed

    Pant, Pallavi; Guttikunda, Sarath K; Peltier, Richard E

    2016-05-01

    Air pollution poses a critical threat to human health with ambient and household air pollution identified as key health risks in India. While there are many studies investigating concentration, composition, and health effects of air pollution, investigators are only beginning to focus on estimating or measuring personal exposure. Further, the relevance of exposures studies from the developed countries in developing countries is uncertain. This review summarizes existing research on exposure to particulate matter (PM) in India, identifies gaps and offers recommendations for future research. There are a limited number of studies focused on exposure to PM and/or associated health effects in India, but it is evident that levels of exposure are much higher than those reported in developed countries. Most studies have focused on coarse aerosols, with a few studies on fine aerosols. Additionally, most studies have focused on a handful of cities, and there are many unknowns in terms of ambient levels of PM as well as personal exposure. Given the high mortality burden associated with air pollution exposure in India, a deeper understanding of ambient pollutant levels as well as source strengths is crucial, both in urban and rural areas. Further, the attention needs to expand beyond the handful large cities that have been studied in detail.

  12. Effects of short- and long-term exposure to ozone on heart rate and blood pressure of emphysematous rats

    SciTech Connect

    Uchiyama, I.; Yokoyama, E.

    1989-02-01

    Electrocardiogram and arterial blood pressure of elastase-treated emphysematous rats (E rats) and saline-treated control rats (S rats) were recorded continuously during exposure to either 1 ppm ozone (O/sub 3/) for 3 hr or 0.5 ppm O/sub 3/ for 6 hr. The heart rates (HRs) of both groups decreased to about 50 and 65% of the initial levels at the end of 1 ppm and 0.5 ppm O/sub 3/ exposure, respectively. Mean arterial blood pressures (MAPs) also decreased to about 76 and 82%, respectively. There was no significant difference in these responses between E and S rats, although the levels of HRs and MAPs of the E rats were always a little lower than those of the S rats. Another group of E and S rats was continuously exposed to 0.2 ppm O/sub 3/ for 4 weeks. The HRs of both E and S groups decreased to about 81 and 88% of the initial levels on the first day, respectively, although they recovered completely by the third day. No significant difference in the variation of HRs during exposure was noted between E and S rats. However, the HR responses of these rats to a challenge exposure of 0.8 ppm O/sub 3/ for 1.5 hr appeared to be different. That is, S rats were more tolerant of the challenge exposure to O/sub 3/ for 1.5 hr than the E rats.

  13. PM2.5 metal exposures and nocturnal heart rate variability: a panel study of boilermaker construction workers

    PubMed Central

    Cavallari, Jennifer M; Eisen, Ellen A; Fang, Shona C; Schwartz, Joel; Hauser, Russ; Herrick, Robert F; Christiani, David C

    2008-01-01

    Background To better understand the mechanism(s) of particulate matter (PM) associated cardiovascular effects, research priorities include identifying the responsible PM characteristics. Evidence suggests that metals play a role in the cardiotoxicity of fine PM (PM2.5) and in exposure-related decreases in heart rate variability (HRV). We examined the association between daytime exposure to the metal content of PM2.5 and night HRV in a panel study of boilermaker construction workers exposed to metal-rich welding fumes. Methods Twenty-six male workers were monitored by ambulatory electrocardiogram (ECG) on a workday while exposed to welding fume and a non-workday (baseline). From the ECG, rMSSD (square root of the mean squared differences of successive intervals) was summarized over the night (0:00–7:00). Workday, gravimetric PM2.5 samples were analyzed by x-ray fluorescence to determine metal content. We used linear mixed effects models to assess the associations between night rMSSD and PM2.5 metal exposures both with and without adjustment for total PM2.5. Matched ECG measurements from the non-workday were used to control for individual cardiac risk factors and models were also adjusted for smoking status. To address collinearity between PM2.5 and metal content, we used a two-step approach that treated the residuals from linear regression models of each metal on PM2.5 as surrogates for the differential effects of metal exposures in models for night rMSSD. Results The median PM2.5 exposure was 650 μg/m3; median metal exposures for iron, manganese, aluminum, copper, zinc, chromium, lead, and nickel ranged from 226 μg/m3 to non-detectable. We found inverse linear associations in exposure-response models with increased metal exposures associated with decreased night rMSSD. A statistically significant association for manganese was observed, with a decline of 0.130 msec (95% CI: -0.162, -0.098) in night rMSSD for every 1 μg/m3 increase in manganese. However, even

  14. Hepatitis B Virus Infection and Immunizations among Asian American College Students: Infection, Exposure, and Immunity Rates

    ERIC Educational Resources Information Center

    Lee, Haeok; Kiang, Peter; Watanabe, Paul; Halon, Patricia; Shi, Ling; Church, Daniel R.

    2013-01-01

    Objectives: To evaluate the prevalence of hepatitis B virus (HBV) infection, exposure, and immunity among Asian American college students as a basis for evaluating HBV screening and vaccination policy. Participants and Methods: Self-identified Asian American college students aged 18 years or older were examined. Serological tests of HBV surface…

  15. Particulate metals and organic compounds from electronic and tobacco-containing cigarettes: comparison of emission rates and secondhand exposure.

    PubMed

    Saffari, Arian; Daher, Nancy; Ruprecht, Ario; De Marco, Cinzia; Pozzi, Paolo; Boffi, Roberto; Hamad, Samera H; Shafer, Martin M; Schauer, James J; Westerdahl, Dane; Sioutas, Constantinos

    2014-01-01

    In recent years, electronic cigarettes have gained increasing popularity as alternatives to normal (tobacco-containing) cigarettes. In the present study, particles generated by e-cigarettes and normal cigarettes have been analyzed and the degree of exposure to different chemical agents and their emission rates were quantified. Despite the 10-fold decrease in the total exposure to particulate elements in e-cigarettes compared to normal cigarettes, specific metals (e.g. Ni and Ag) still displayed a higher emission rate from e-cigarettes. Further analysis indicated that the contribution of e-liquid to the emission of these metals is rather minimal, implying that they likely originate from other components of the e-cigarette device or other indoor sources. Organic species had lower emission rates during e-cigarette consumption compared to normal cigarettes. Of particular note was the non-detectable emission of polycyclic aromatic hydrocarbons (PAHs) from e-cigarettes, while substantial emission of these species was observed from normal cigarettes. Overall, with the exception of Ni, Zn, and Ag, the consumption of e-cigarettes resulted in a remarkable decrease in secondhand exposure to all metals and organic compounds. Implementing quality control protocols on the manufacture of e-cigarettes would further minimize the emission of metals from these devices and improve their safety and associated health effects.

  16. Links between self-reported media violence exposure and teacher ratings of aggression and prosocial behavior among German adolescents.

    PubMed

    Krahé, Barbara; Möller, Ingrid

    2011-04-01

    The relations between adolescents' habitual usage of media violence and their tendency to engage in aggressive and prosocial behavior in a school setting were examined in a cross-sectional study with 1688 7th and 8th graders in Germany who completed measures of violent media exposure and normative acceptance of aggression. For each participant, ratings of prosocial and aggressive behavior were obtained from their class teacher. Media violence exposure was a unique predictor of teacher-rated aggression even when relevant covariates were considered, and it predicted prosocial behavior over and above gender. Path analyses confirmed a direct positive link from media violence usage to teacher-rated aggression for girls and boys, but no direct negative link to prosocial behavior was found. Indirect pathways were identified to higher aggressive and lower prosocial behavior via the acceptance of aggression as normative. Although there were significant gender differences in media violence exposure, aggression, and prosocial behavior, similar path models were identified for boys and girls.

  17. Links between self-reported media violence exposure and teacher ratings of aggression and prosocial behavior among German adolescents.

    PubMed

    Krahé, Barbara; Möller, Ingrid

    2011-04-01

    The relations between adolescents' habitual usage of media violence and their tendency to engage in aggressive and prosocial behavior in a school setting were examined in a cross-sectional study with 1688 7th and 8th graders in Germany who completed measures of violent media exposure and normative acceptance of aggression. For each participant, ratings of prosocial and aggressive behavior were obtained from their class teacher. Media violence exposure was a unique predictor of teacher-rated aggression even when relevant covariates were considered, and it predicted prosocial behavior over and above gender. Path analyses confirmed a direct positive link from media violence usage to teacher-rated aggression for girls and boys, but no direct negative link to prosocial behavior was found. Indirect pathways were identified to higher aggressive and lower prosocial behavior via the acceptance of aggression as normative. Although there were significant gender differences in media violence exposure, aggression, and prosocial behavior, similar path models were identified for boys and girls. PMID:20627370

  18. Fischer-Tropsch synthesis in supercritical phase carbon dioxide: Recycle rates

    NASA Astrophysics Data System (ADS)

    Soti, Madhav

    With increasing oil prices and attention towards the reduction of anthropogenic CO2, the use of supercritical carbon dioxide for Fischer Tropsch Synthesis (FTS) is showing promise in fulfilling the demand of clean liquid fuels. The evidence of consumption of carbon dioxide means that it need not to be removed from the syngas feed to the Fischer Tropsch reactor after the gasification process. Over the last five years, research at SIUC have shown that FTS in supercritical CO2reduces the selectivities for methane, enhances conversion, reduces the net CO2produces in the coal to liquid fuels process and increase the life of the catalyst. The research has already evaluated the impact of various operating and feed conditions on the FTS for the once through process. We believe that the integration of unreacted feed recycle would enhance conversion, increase the yield and throughput of liquid fuels for the same reactor size. The proposed research aims at evaluating the impact of recycle of the unreacted feed gas along with associated product gases on the performance of supercritical CO2FTS. The previously identified conditions will be utilized and various recycle ratios will be evaluated in this research once the recycle pump and associated fittings have been integrated to the supercritical CO2FTS. In this research two different catalysts (Fe-Zn-K, Fe-Co-Zn-K) were analyzed under SC-FTS in different recycle rate at 350oC and 1200 psi. The use of recycle was found to improve conversion from 80% to close to 100% with both catalysts. The experiment recycle rate at 4.32 and 4.91 was clearly surpassing theoretical recycle curve. The steady state reaction rate constant was increased to 0.65 and 0.8 min-1 for recycle rate of 4.32 and 4.91 respectively. Carbon dioxide selectivity was decreased for both catalyst as it was converting to carbon monoxide. Carbon dioxide consumption was increased from 0.014 to 0.034 mole fraction. This concluded that CO2is being used in the system and

  19. Estimated dose rates to members of the public from external exposure to patients with {sup 131}I thyroid treatment

    SciTech Connect

    Dewji, S. Bellamy, M.; Leggett, R.; Eckerman, K.; Hertel, N.; Sherbini, S.; Saba, M.

    2015-04-15

    Purpose: Estimated dose rates that may result from exposure to patients who had been administered iodine-131 ({sup 131}I) as part of medical therapy were calculated. These effective dose rate estimates were compared with simplified assumptions under United States Nuclear Regulatory Commission Regulatory Guide 8.39, which does not consider body tissue attenuation nor time-dependent redistribution and excretion of the administered {sup 131}I. Methods: Dose rates were estimated for members of the public potentially exposed to external irradiation from patients recently treated with {sup 131}I. Tissue attenuation and iodine biokinetics were considered in the patient in a larger comprehensive effort to improve external dose rate estimates. The external dose rate estimates are based on Monte Carlo simulations using the Phantom with Movable Arms and Legs (PIMAL), previously developed by Oak Ridge National Laboratory and the United States Nuclear Regulatory Commission. PIMAL was employed to model the relative positions of the {sup 131}I patient and members of the public in three exposure scenarios: (1) traveling on a bus in a total of six seated or standing permutations, (2) two nursing home cases where a caregiver is seated at 30 cm from the patient’s bedside and a nursing home resident seated 250 cm away from the patient in an adjacent bed, and (3) two hotel cases where the patient and a guest are in adjacent rooms with beds on opposite sides of the common wall, with the patient and guest both in bed and either seated back-to-back or lying head to head. The biokinetic model predictions of the retention and distribution of {sup 131}I in the patient assumed a single voiding of urinary bladder contents that occurred during the trip at 2, 4, or 8 h after {sup 131}I administration for the public transportation cases, continuous first-order voiding for the nursing home cases, and regular periodic voiding at 4, 8, or 12 h after administration for the hotel room cases. Organ

  20. Estimated dose rates to members of the public from external exposure to patients with 131I thyroid treatment

    DOE PAGES

    Dewji, S.; Bellamy, M.; Hertel, N.; Leggett, R.; Sherbini, S.; Saba, M.; Eckerman, K.

    2015-03-25

    The purpose of this study is to estimate dose rates that may result from exposure to patients who had been administered iodine-131 (131I) as part of medical therapy were calculated. These effective dose rate estimates were compared with simplified assumptions under United States Nuclear Regulatory Commission Regulatory Guide 8.39, which does not consider body tissue attenuation nor time-dependent redistribution and excretion of the administered 131I. Methods: Dose rates were estimated for members of the public potentially exposed to external irradiation from patients recently treated with 131I. Tissue attenuation and iodine biokinetics were considered in the patient in a larger comprehensivemore » effort to improve external dose rate estimates. The external dose rate estimates are based on Monte Carlo simulations using the Phantom with Movable Arms and Legs (PIMAL), previously developed by Oak Ridge National Laboratory and the United States Nuclear Regulatory Commission. PIMAL was employed to model the relative positions of the 131I patient and members of the public in three exposure scenarios: (1) traveling on a bus in a total of six seated or standing permutations, (2) two nursing home cases where a caregiver is seated at 30 cm from the patient’s bedside and a nursing home resident seated 250 cm away from the patient in an adjacent bed, and (3) two hotel cases where the patient and a guest are in adjacent rooms with beds on opposite sides of the common wall, with the patient and guest both in bed and either seated back-to-back or lying head to head. The biokinetic model predictions of the retention and distribution of 131I in the patient assumed a single voiding of urinary bladder contents that occurred during the trip at 2, 4, or 8 h after 131I administration for the public transportation cases, continuous first-order voiding for the nursing home cases, and regular periodic voiding at 4, 8, or 12 h after administration for the hotel room cases. Organ

  1. Occupational exposure and 25-year incidence rate of non-specific lung disease: the Zutphen Study.

    PubMed

    Heederik, D; Kromhout, H; Burema, J; Biersteker, K; Kromhout, D

    1990-12-01

    Information gathered in the Zutphen Study, the Dutch contribution to the Seven Countries Study that started in the 1960s, was used for the present study. In 1960 878 men participated in the physical examination and they were followed for 25 years until 1 July 1985. During this follow-up, their morbidity status was verified regularly. With this information the occurrence of chronic non-specific lung disease (CNSLD) at a specific time was coded by one physician, using strict criteria. The CNSLD diagnosis was based on the following criteria: episodes of respiratory symptoms such as regular cough and phlegm for longer than three months or episodes of wheezing and shortness of breath reported to the survey physician, or: diagnosis of CNSLD, including chronic bronchitis or emphysema by a clinical specialist. Occupation in 1960 was coded and used to generate specific occupational exposures with a Job Exposure Matrix. Because the exact time of diagnosis of CNSLD was known, incidence densities could be calculated. For 804 men a complete set of data was available. A Poisson regression analysis was used to analyse the relationships between the incidence density and independent variables like age, calendar period, occupation and specific occupational exposures. Blue collar workers had a significantly elevated incidence density ratio (IDR) compared to white collar workers (1.82, 95% confidence limits (CL): 1.35, 2.46). Subgroups of blue collar workers, wood and paper workers, textile workers, and tailors, construction workers and transport workers had significantly elevated IDRs also. Of the specific exposures heavy metals, mineral dust and adhesives had a significantly elevated IDR.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2084026

  2. Estimated rate of fatal automobile accidents attributable to acute solvent exposure at low inhaled concentrations.

    PubMed

    Benignus, Vernon A; Bushnell, Philip J; Boyes, William K

    2011-12-01

    Acute solvent exposures may contribute to automobile accidents because they increase reaction time and decrease attention, in addition to impairing other behaviors. These effects resemble those of ethanol consumption, both with respect to behavioral effects and neurological mechanisms. These observations, along with the extensive data on the relationship between ethanol consumption and fatal automobile accidents, suggested a way to estimate the probability of fatal automobile accidents from solvent inhalation. The problem can be approached using the logic of the algebraic transitive postulate of equality: if A=B and B=C, then A=C. We first calculated a function describing the internal doses of solvent vapors that cause the same magnitude of behavioral impairment as ingestion of ethanol (A=B). Next, we fit a function to data from the literature describing the probability of fatal car crashes for a given internal dose of ethanol (B=C). Finally, we used these two functions to generate a third function to estimate the probability of a fatal car crash for any internal dose of organic solvent vapor (A=C). This latter function showed quantitatively (1) that the likelihood of a fatal car crash is increased by acute exposure to organic solvent vapors at concentrations less than 1.0 ppm, and (2) that this likelihood is similar in magnitude to the probability of developing leukemia from exposure to benzene. This approach could also be applied to other potentially adverse consequences of acute exposure to solvents (e.g., nonfatal car crashes, property damage, and workplace accidents), if appropriate data were available.

  3. Effects of Oral Exposure Duration and Gastric Energy Content on Appetite Ratings and Energy Intake in Lean Men

    PubMed Central

    Wijlens, Anne G. M.; de Graaf, Cees; Erkner, Alfrun; Mars, Monica

    2016-01-01

    Studies show that longer oral exposure to food leads to earlier satiation and lowers energy intake. Moreover, higher energy content of food has been shown to lead to higher satiety. Up to now, it has not been studied systematically how oral exposure duration and gastric energy content interact in satiety regulation. Thirty-seven men (22 ± 4 years, 22 ± 2 kg/m2) participated in a randomized cross-over trial, in which we independently manipulated: (1) oral exposure duration by modified sham feeding (MSF) for 1 or 8 min; and (2) energy content of gastric load (GL) by a nasogastric tube: 100 kcal/500 mL or 700 kcal/500 mL. Outcome measures were appetite ratings and subsequent energy intake from an ad libitum meal. Energy intake was 35% lower after the GLs with 700 kcal than with 100kcal (p < 0.0001). All appetite ratings were lower in the 700 kcal than in the 100 kcal treatments (area under the curve (AUC); p-values ≤ 0.002); fullness was higher and prospective consumption was lower in the 8 min than in the 1 min MSF treatments (AUC; p-values ≤ 0.02). In conclusion, the current showed that a GL of 700 kcal/500 mL vs. 100 kcal/500 mL increased satiety and lowered energy intake. No additional effects of oral exposure duration could be observed, presumably due to the high contrast in energy between the manipulations. Future research should also focus on the role of oral exposure as such and not only the duration. PMID:26821045

  4. Effects of Oral Exposure Duration and Gastric Energy Content on Appetite Ratings and Energy Intake in Lean Men.

    PubMed

    Wijlens, Anne G M; de Graaf, Cees; Erkner, Alfrun; Mars, Monica

    2016-01-26

    Studies show that longer oral exposure to food leads to earlier satiation and lowers energy intake. Moreover, higher energy content of food has been shown to lead to higher satiety. Up to now, it has not been studied systematically how oral exposure duration and gastric energy content interact in satiety regulation. Thirty-seven men (22 ± 4 years, 22 ± 2 kg/m²) participated in a randomized cross-over trial, in which we independently manipulated: (1) oral exposure duration by modified sham feeding (MSF) for 1 or 8 min; and (2) energy content of gastric load (GL) by a nasogastric tube: 100 kcal/500 mL or 700 kcal/500 mL. Outcome measures were appetite ratings and subsequent energy intake from an ad libitum meal. Energy intake was 35% lower after the GLs with 700 kcal than with 100 kcal (p < 0.0001). All appetite ratings were lower in the 700 kcal than in the 100 kcal treatments (area under the curve (AUC); p-values ≤ 0.002); fullness was higher and prospective consumption was lower in the 8 min than in the 1 min MSF treatments (AUC; p-values ≤ 0.02). In conclusion, the current showed that a GL of 700 kcal/500 mL vs. 100 kcal/500 mL increased satiety and lowered energy intake. No additional effects of oral exposure duration could be observed, presumably due to the high contrast in energy between the manipulations. Future research should also focus on the role of oral exposure as such and not only the duration.

  5. Effect of cupric ions on the initiation protein synthesis rate in the human endometrium.

    PubMed

    Hernandez-Perez, O; Luna, G; Mercado, E; Delgado, N; Rosado, A

    1989-12-01

    The effect of cupric ions on the initiation protein synthesis rate of the human endometrium was studied. Addition of copper to the complete ribosomal system decreased the binding of [3H]Met-tRNA(i) to the isolated ribosomes with a plateau at about 70% inhibition with concentrations higher than 150 microM. The initiation activity was GTP-dependent with a maximum at 2 mM. This activity was very rapid, requiring 5 min to complete the reaction. Incubation of isolated initiation factors with copper (300 microM) inhibited the formation of the ternary complex. When the complete system was reconstituted with salt-washed ribosomes after ternary complex formation, no significant change on the inhibition pattern was observed. Addition of initiation factors to 5-min preincubated salt-washed ribosomes with 300 microM copper, after the elimination of excess copper, induced only a 12% decrease on Met-tRNA(i) binding. This effect was not modified by the presence of Sparsomycin, an elongation inhibitor. It was concluded that copper interferes with the initiation process, probably at the ternary complex formation level.

  6. Dietary crude protein intake influences rates of whole-body protein synthesis in weanling horses.

    PubMed

    Tanner, S L; Wagner, A L; Digianantonio, R N; Harris, P A; Sylvester, J T; Urschel, K L

    2014-11-01

    The objective of this study was to measure whole-body protein kinetics in weanling horses receiving forage and one of two different concentrates: (1) commercial crude protein (CCP) concentrate, which with the forage provided 4.1 g CP/kg bodyweight (BW)/day (189 mg lysine (Lys)/kg BW/day), and (2) recommended crude protein (RCP) concentrate which, with the same forage, provided 3.1 g CP/kg BW/day (194 mg Lys/kg BW/day). Blood samples were taken to determine the response of plasma amino acid concentrations to half the daily concentrate allocation. The next day, a 2 h-primed, constant infusion of [(13)C]sodium bicarbonate and a 4 h-primed, constant infusion of [1-(13)C]phenylalanine were used with breath and blood sampling to measure breath (13)CO2 and blood [(13)C]phenylalanine enrichment. Horses on the CCP diet showed an increase from baseline in plasma isoleucine, leucine, lysine, threonine, valine, alanine, arginine, asparagine, glutamine, ornithine, proline, serine, and tyrosine at 120 min post-feeding. Baseline plasma amino acid concentrations were greater with the CCP diet for histidine, isoleucine, leucine, threonine, valine, asparagine, proline, and serine. Phenylalanine, lysine, and methionine were greater in the plasma of horses receiving the RCP treatment at 0 and 120 min. Phenylalanine intake was standardized between groups; however, horses receiving the RCP diet had greater rates of phenylalanine oxidation (P = 0.02) and lower rates of non-oxidative phenylalanine disposal (P = 0.04). Lower whole-body protein synthesis indicates a limiting amino acid in the RCP diet. PMID:24973006

  7. The effect of laser repetition rate on the LASiS synthesis of biocompatible silver nanoparticles in aqueous starch solution

    PubMed Central

    Zamiri, Reza; Zakaria, Azmi; Ahangar, Hossein Abbastabar; Darroudi, Majid; Zamiri, Golnoosh; Rizwan, Zahid; Drummen, Gregor PC

    2013-01-01

    Laser ablation-based nanoparticle synthesis in solution is rapidly becoming popular, particularly for potential biomedical and life science applications. This method promises one pot synthesis and concomitant bio-functionalization, is devoid of toxic chemicals, does not require complicated apparatus, can be combined with natural stabilizers, is directly biocompatible, and has high particle size uniformity. Size control and reduction is generally determined by the laser settings; that the size and size distribution scales with laser fluence is well described. Conversely, the effect of the laser repetition rate on the final nanoparticle product in laser ablation is less well-documented, especially in the presence of stabilizers. Here, the influence of the laser repetition rate during laser ablation synthesis of silver nanoparticles in the presence of starch as a stabilizer was investigated. The increment of the repetition rate does not negatively influence the ablation efficiency, but rather shows increased productivity, causes a red-shift in the plasmon resonance peak of the silver–starch nanoparticles, an increase in mean particle size and size distribution, and a distinct lack of agglomerate formation. Optimal results were achieved at 10 Hz repetition rate, with a mean particle size of ~10 nm and a bandwidth of ~6 nm ‘full width at half maximum’ (FWHM). Stability measurements showed no significant changes in mean particle size or agglomeration or even flocculation. However, zeta potential measurements showed that optimal double layer charge is achieved at 30 Hz. Consequently, Ag–NP synthesis via the laser ablation synthesis in solution (LASiS) method in starch solution seems to be a trade-off between small size and narrow size distributions and inherent and long-term stability. PMID:23345971

  8. The effect of laser repetition rate on the LASiS synthesis of biocompatible silver nanoparticles in aqueous starch solution.

    PubMed

    Zamiri, Reza; Zakaria, Azmi; Ahangar, Hossein Abbastabar; Darroudi, Majid; Zamiri, Golnoosh; Rizwan, Zahid; Drummen, Gregor P C

    2013-01-01

    Laser ablation-based nanoparticle synthesis in solution is rapidly becoming popular, particularly for potential biomedical and life science applications. This method promises one pot synthesis and concomitant bio-functionalization, is devoid of toxic chemicals, does not require complicated apparatus, can be combined with natural stabilizers, is directly biocompatible, and has high particle size uniformity. Size control and reduction is generally determined by the laser settings; that the size and size distribution scales with laser fluence is well described. Conversely, the effect of the laser repetition rate on the final nanoparticle product in laser ablation is less well-documented, especially in the presence of stabilizers. Here, the influence of the laser repetition rate during laser ablation synthesis of silver nanoparticles in the presence of starch as a stabilizer was investigated. The increment of the repetition rate does not negatively influence the ablation efficiency, but rather shows increased productivity, causes a red-shift in the plasmon resonance peak of the silver-starch nanoparticles, an increase in mean particle size and size distribution, and a distinct lack of agglomerate formation. Optimal results were achieved at 10 Hz repetition rate, with a mean particle size of ~10 nm and a bandwidth of ~6 nm 'full width at half maximum' (FWHM). Stability measurements showed no significant changes in mean particle size or agglomeration or even flocculation. However, zeta potential measurements showed that optimal double layer charge is achieved at 30 Hz. Consequently, Ag-NP synthesis via the laser ablation synthesis in solution (LASiS) method in starch solution seems to be a trade-off between small size and narrow size distributions and inherent and long-term stability.

  9. Sucrose phosphate synthase activity rises in correlation with high-rate cellulose synthesis in three heterotrophic systems.

    PubMed

    Babb, V M; Haigler, C H

    2001-11-01

    Based on work with cotton fibers, a particulate form of sucrose (Suc) synthase was proposed to support secondary wall cellulose synthesis by degrading Suc to fructose and UDP-glucose. The model proposed that UDP-glucose was then channeled to cellulose synthase in the plasma membrane, and it implies that Suc availability in cellulose sink cells would affect the rate of cellulose synthesis. Therefore, if cellulose sink cells could synthesize Suc and/or had the capacity to recycle the fructose released by Suc synthase back to Suc, cellulose synthesis might be supported. The capacity of cellulose sink cells to synthesize Suc was tested by analyzing the Suc phosphate synthase (SPS) activity of three heterotrophic systems with cellulose-rich secondary walls. SPS is a primary regulator of the Suc synthesis rate in leaves and some Suc-storing, heterotrophic organs, but its activity has not been previously correlated with cellulose synthesis. Two systems analyzed, cultured mesophyll cells of Zinnia elegans L. var. Envy and etiolated hypocotyls of kidney beans (Phaseolus vulgaris), contained differentiating tracheary elements. Cotton (Gossypium hirsutum L. cv Acala SJ-1) fibers were also analyzed during primary and secondary wall synthesis. SPS activity rose in all three systems during periods of maximum cellulose deposition within secondary walls. The Z. elegans culture system was manipulated to establish a tight linkage between the timing of tracheary element differentiation and rising SPS activity and to show that SPS activity did not depend on the availability of starch for degradation. The significance of these findings in regard to directing metabolic flux toward cellulose will be discussed. PMID:11706202

  10. COMBINED ENDOCRINE EFFECTS OF IN UTERO EXPOSURE TO THE ANTIANDROGENS BUTYLBENZYL PHTHALATE (BBP) AND LINURON (LIN) ON FETAL TESTOSTERONE (T) SYNTHESIS AND REPRODUCTIVE TRACT DEVELOPMENT

    EPA Science Inventory

    COMBINED ENDOCRINE EFFECTS OF IN UTERO EXPOSURE TO THE ANTIANDROGENS BUTYLBENZYL PHTHALATE (BBP) AND LINURON (Lin) ON FETAL TESTOSTERONE (T) SYNTHESIS AND REPRODUCTIVE TRACT DEVELOPMENT
    Parks LG , Hotchkiss AK, Ostby J, Lambright C and Gray LE, Jr.

    Lin and BBP are toxic...

  11. The solar UV exposure time required for vitamin D3 synthesis in the human body estimated by numerical simulation and observation in Japan

    NASA Astrophysics Data System (ADS)

    Nakajima, Hideaki; Miyauchi, Masaatsu; Hirai, Chizuko

    2013-04-01

    After the discovery of Antarctic ozone hole, the negative effect of exposure of human body to harmful solar ultraviolet (UV) radiation is widely known. However, there is positive effect of exposure to UV radiation, i.e., vitamin D synthesis. Although the importance of solar UV radiation for vitamin D3 synthesis in the human body is well known, the solar exposure time required to prevent vitamin D deficiency has not been well determined. This study attempted to identify the time of solar exposure required for vitamin D3 synthesis in the body by season, time of day, and geographic location (Sapporo, Tsukuba, and Naha, in Japan) using both numerical simulations and observations. According to the numerical simulation for Tsukuba at noon in July under a cloudless sky, 2.3 min of solar exposure are required to produce 5.5 μg vitamin D3 per 600 cm2 skin. This quantity of vitamin D represents the recommended intake for an adult by the Ministry of Health, Labour and Welfare, and the 2010 Japanese Dietary Reference Intakes (DRIs). In contrast, it took 49.5 min to produce the same amount of vitamin D3 at Sapporo in the northern part of Japan in December, at noon under a cloudless sky. The necessary exposure time varied considerably with the time of the day. For Tsukuba at noon in December, 14.5 min were required, but at 09:00 68.7 min were required and at 15:00 175.8 min were required for the same meteorological conditions. Naha receives high levels of UV radiation allowing vitamin D3 synthesis almost throughout the year. According to our results, we are further developing an index to quantify the necessary time of UV radiation exposure to produce required amount of vitamin D3 from a UV radiation data.

  12. Requirements regarding dose rate and exposure time for killing of tumour cells in beta particle radionuclide therapy

    PubMed Central

    Eriksson, Veronika; Stenerlöw, Bo; Lundqvist, Hans

    2006-01-01

    Purpose The purpose of this study was to identify combinations of dose rate and exposure time that have the potential to provide curative treatment with targeted radionuclide therapy applying low dose rate beta irradiation. Methods Five tumour cell lines, U-373MG and U-118MG gliomas, HT-29 colon carcinoma, A-431 cervical squamous carcinoma and SKBR-3 breast cancer, were used. An experimental model with 105 tumour cells in each sample was irradiated with low dose rate beta particles. The criterion for successful treatment was absence of recovery of cells during a follow-up period of 3 months. The initial dose rates were in the range 0.1–0.8 Gy/h, and the cells were continuously exposed for 1, 3 or 7 days. These combinations covered dose rates and doses achievable in targeted radionuclide therapy. Results Continuous irradiation with dose rates of 0.2–0.3 and 0.4–0.6 Gy/h for 7 and 3 days, respectively, could kill all cells in each tumour cell sample. These treatments gave total radiation doses of 30–40 Gy. However, when exposed for just 24 h with about 0.8 Gy/h, only the SKBR-3 cells were successfully treated; all the other cell types recovered. There were large cell type-dependent variations in the growth delay patterns for the cultures that recovered. The U-118MG cells were most resistant and the U-373MG and SKBR-3 cells most sensitive to the treatments. The HT-29 and A-431 cells were intermediate. Conclusion The results serve as a guideline for the combinations of dose rate and exposure time necessary to kill tumour cells when applying low dose rate beta irradiation. The shift from recovery to “cure” fell within a narrow range of dose rate and exposure time combinations. PMID:16718515

  13. Prenatal alcohol exposure, blood alcohol concentrations and alcohol elimination rates for the mother, fetus and newborn.

    PubMed

    Burd, L; Blair, J; Dropps, K

    2012-09-01

    Fetal alcohol spectrum disorders (FASDs) are a common cause of intellectual impairment and birth defects. More recently, prenatal alcohol exposure (PAE) has been found to be a risk factor for fetal mortality, stillbirth and infant and child mortality. This has led to increased concern about detection and management of PAE. One to 2 h after maternal ingestion, fetal blood alcohol concentrations (BACs) reach levels nearly equivalent to maternal levels. Ethanol elimination by the fetus is impaired because of reduced metabolic capacity. Fetal exposure time is prolonged owing to the reuptake of amniotic-fluid containing ethanol by the fetus. Alcohol elimination from the fetus relies on the mother's metabolic capacity. Metabolic capacity among pregnant women varies eightfold (from 0.0025 to 0.02 g dl(-1)  h(-1)), which may help explain how similar amounts of ethanol consumption during pregnancy results in widely varying phenotypic presentations of FASD. At birth physiological changes alter the neonate's metabolic capacity and it rapidly rises to a mean value of 83.5% of the mother's capacity. FASDs are highly recurrent and younger siblings have increased risk. Detection of prenatal alcohol use offers an important opportunity for office-based interventions to decrease exposure for the remainder of pregnancy and identification of women who need substance abuse treatment. Mothers of children with FAS have been found to drink faster, get drunk quicker and to have higher BACs. A modest increase in the prevalence of a polymorphism of alcohol dehydrogenase, which increases susceptibility to adverse outcomes from PAE has been reported. Lastly, detection of alcohol use and appropriate management would decrease risk from PAE for subsequent pregnancies.

  14. Injury to the blood-testis barrier after low-dose-rate chronic radiation exposure in mice.

    PubMed

    Son, Y; Heo, K; Bae, M J; Lee, C G; Cho, W S; Kim, S D; Yang, K; Shin, I S; Lee, M Y; Kim, J S

    2015-11-01

    Exposure to ionising radiation induces male infertility, accompanied by increasing permeability of the blood-testis barrier. However, the effect on male fertility by low-dose-rate chronic radiation has not been investigated. In this study, the effects of low-dose-rate chronic radiation on male mice were investigated by measuring the levels of tight-junction-associated proteins (ZO-1 and occludin-1), Niemann-Pick disease type 2 protein (NPC-2) and antisperm antibody (AsAb) in serum. BALB/c mice were exposed to low-dose-rate radiation (3.49 mGy h(-1)) for total exposures of 0.02 (6 h), 0.17 (2 d) and 1.7 Gy (21 d). Based on histological examination, the diameter and epithelial depth of seminiferous tubules were significantly decreased in 1.7-Gy-irradiated mice. Compared with those of the non-irradiated group, 1.7-Gy-irradiated mice showed significantly decreased ZO-1, occludin-1 and NPC-2 protein levels, accompanied with increased serum AsAb levels. These results suggest potential blood-testis barrier injury and immune infertility in male mice exposed to low-dose-rate chronic radiation.

  15. Effects of pre- and postnatal polychlorinated biphenyl exposure on metabolic rate and thyroid hormones of white-footed mice

    USGS Publications Warehouse

    French, J.B.; Voltura, M.B.; Tomasi, T.E.

    2001-01-01

    Energy budgets have proven to be a valuable tool for predicting life history from physiological data in terrestrial vertebrates, yet these concepts have not been applied to the physiological effects of contaminants. Contaminants might affect energy budgets by imposing an additional metabolic cost or by reducing the overall amount of energy taken in; either process will reduce the energy available for production (i.e., growth or reproduction). This study examined whole animal energetic effects of polychlorinated biphenyl (PCB) exposure in white-footed mice (Peromyscus leucopus). Exposure to PCBs is known to reduce concentrations of plasma thyroid hormones, and thyroid hormones exert strong control over the rate of energy metabolism in mammals. Peromyscus leucopus that were proven breeders were fed PCBs in their food at 0, 10, and 25 ppm. Through lactation, offspring were exposed to PCB from conception and were maintained on the maternal diet to adulthood. No effects were seen on energy metabolism (O-2 consumption, measured in adulthood) or on growth, but there were large dose-dependent decreases in thyroid hormone concentrations, particularly T-4. The apparent disparity in our data between unchanged metabolic rates and 50% reductions in T-4 concentrations can be rationalized by noting that free T-3 (the fraction not bound to plasma protein) in treated mice was not significantly different from controls and that metabolism is most strongly influenced by free T-3. Overall, this study did not demonstrate any energetic consequences of PCB exposure in P. leucopus at dietary concentrations up to 25 ppm.

  16. Dealing with consumer differences in liking during repeated exposure to food; typical dynamics in rating behavior.

    PubMed

    Dalenberg, Jelle R; Nanetti, Luca; Renken, Remco J; de Wijk, René A; Ter Horst, Gert J

    2014-01-01

    Consumers show high interindividual variability in food liking during repeated exposure. To investigate consumer liking during repeated exposure, data is often interpreted on a product level by averaging results over all consumers. However, a single product may elicit inconsistent behaviors in consumers; averaging will mix and hide possible subgroups of consumer behaviors, leading to a misinterpretation of the results. To deal with the variability in consumer liking, we propose to use clustering on data from consumer-product combinations to investigate the nature of the behavioral differences within the complete dataset. The resulting behavioral clusters can then be used to describe product acceptance. To test this approach we used two independent data sets in which young adults were repeatedly exposed to drinks and snacks, respectively. We found that five typical consumer behaviors existed in both datasets. These behaviors differed both in the average level of liking as well as its temporal dynamics. By investigating the distribution of a single product across typical consumer behaviors, we provide more precise insight in how consumers divide in subgroups based on their product liking (i.e. product modality). This work shows that taking into account and using interindividual differences can unveil information about product acceptance that would otherwise be ignored.

  17. Ca-41 in iron falls, Grant and Estherville - Production rates and related exposure age calculations

    NASA Technical Reports Server (NTRS)

    Fink, D.; Klein, J.; Middleton, R.; Vogt, S.; Herzog, G. F.

    1991-01-01

    Results are presented of the first phase of a Ca-41 cosmogenic studies program aimed at establishing baseline concentrations and trends in selected meteorites and the use of Ca-41 in estimating exposure ages and preatmospheric meteorite radii. The average Ca-41 saturation activity recorded in four small iron falls is 24 +/-1 dpm/kg. This finding, together with measurements at the center and surface of the large iron Grant, indicates that production of Ca-41 from spallation on iron is weakly dependent on shielding to depths as large as 250 g/sq cm. The (K-41)-Ca-41 exposure age of Grant is estimated at 330 +/-50 My, and an upper limit to its terrestrial age of 43 +/-15 ky. A comparison of the Ca-41 contents of stony and metallic material separated from the mesosiderite Estherville identifies low-energy neutron capture on native Ca as a second important channel of production. It is found that the Ca-41 signal in the stone phase from three meteorites correlates with their size, and that the inferred low-energy neutron fluxes vary by a factor of at least 20.

  18. Measurement of local rates of brain protein synthesis by quantitative autoradiography: validation with L-(/sup 3/H)valine

    SciTech Connect

    Dwyer, B.E.; Donatoni, P.; Wasterlain, C.G.

    1982-12-01

    Following the injection of 4-day old rats with 150 mM L-(3,4-/sup 3/H)valine (10 mumol/g, IP) the incorporation of /sup 3/H into protein was linear 2 hours. Valine specific activity in the brain acid-soluble fraction was constant between 30 and 120 min after injection with a mean value of 82.3% of the injectate. Significant amounts of tritated metabolites accumulated in the brain acid-soluble fraction (41.4% of radioactivity at 120 min) but do not prove an impediment to measuring rates of protein synthesis. The rate of protein synthesis in cerebral cortex of the 4-day old rat was measured by quantitative autoradiography using (/sup 3/H)valine and /sup 3/H-sensitive film. The measured rate shows excellent agreement with that found previously using L-(1-/sup 14/C)valine. Our results suggest that (/sup 3/H)valine can be a useful precursor to measure local rates of brain protein synthesis by quantitative autoradiography.

  19. The effects of cutting or of stretching skeletal muscle in vitro on the rates of protein synthesis and degradation

    NASA Technical Reports Server (NTRS)

    Seider, M. J.; Kapp, R.; Chen, C.-P.; Booth, F. W.

    1980-01-01

    Skeletal muscle preparations using cut muscle fibers have often been used in studies of protein metabolism. The present paper reports an investigation of the effect of muscle cutting or stretching in vitro on the rates of protein synthesis and/or degradation. Protein synthesis and content, and ATP and phosphocreatine levels were monitored in soleus and extensor digitorum longus muscles from the rat with various extents of muscle fiber cuts and following stretching to about 120% the resting length. Rates of protein synthesis are found to be significantly lower and protein degradation higher in the cut muscles than in uncut controls, while ATP and phosphocreatine concentrations decreased. Stretched intact muscles, on the other hand, are observed to have higher concentrations of high-energy phosphates than unstretched muscles, while rates of protein degradation were not affected. Results thus demonstrate that the cutting of skeletal muscle fibers alters many aspects of muscle metabolism, and that moderate decreases in ATP concentration do not alter rates of protein concentration in intact muscles in vitro.

  20. Synthesis of siderophores by plant-associated metallotolerant bacteria under exposure to Cd(2.).

    PubMed

    Złoch, Michał; Thiem, Dominika; Gadzała-Kopciuch, Renata; Hrynkiewicz, Katarzyna

    2016-08-01

    Rhizosphere and endophytic bacteria are well known producers of siderophores, organic compounds that chelate ferric iron (Fe(3+)), and therefore play an important role in plant growth promotion in metalliferous areas, thereby improving bioremediation processes. However, in addition to their primary function in iron mobilization, siderophores also have the capacity to chelate other heavy metals, such as Al(3+), Zn(2+), Cu(2+), Pb(2+) and Cd(2+), that can affect homeostasis and the heavy metal tolerance of microorganisms. The main goal of our study was to select the most efficient siderophore-producing bacterial strains isolated from the roots (endophytes) and rhizosphere of Betula pendula L. and Alnus glutinosa L. growing at two heavy metal contaminated sites in southern Poland. Siderophore biosynthesis of these strains in the presence of increasing concentrations of Cd(2+) (0, 0.5, 1, 2 and 3 mM) under iron-deficiency conditions was analysed using spectrophotometric chemical tests for hydroxamates, catecholates and phenolates, as well as the separation of bacterial siderophores by HPLC and characterization of their structure by UHPLC-QTOF/MS. We proved that (i) siderophore-producing bacterial strains seems to be more abundant in the rhizosphere (47%) than in root endophytes (18%); (ii) the strains most effective at siderophore synthesis belonged to the genus Streptomyces and were able to secrete three types of siderophores under Cd(2+) stress: hydroxamates, catecholates and phenolates; (iii) in general, the addition of Cd(2+) enhanced siderophore synthesis, particularly ferrioxamine B synthesis, which may indicate that siderophores play a significant role in tolerance to Cd(2+) in Streptomyces sp. PMID:27183333

  1. The exposure rate to hepatitis B and C viruses among medical waste handlers in three government hospitals, southern Ethiopia

    PubMed Central

    2016-01-01

    OBJECTIVES: The aim of this study was to assess the rate of and risk factors for exposure to hepatitis B virus (HBV) and hepatitis C virus (HCV) among medical waste handlers. METHODS: A cross-sectional study was conducted from December 2014 to January 2015. A total of 152 medical waste handlers (MWH) and 82 non-medical waste handlers (NMWH) were studied. Serum samples were collected from participants and screened for hepatitis B surface antigen (HBsAg), hepatitis B core antibody (anti-HBc) and anti-HCV using rapid immunochromatography assay. MWH were also screened for hepatitis B surface antibody (anti-HBs). RESULTS: The respective prevalence of HBsAg, anti-HBc and anti-HCV was 1.3%, 39.4%, and 0.7% in MWH, compared to 2.4%, 17.1%, and 1.2%, respectively, in NMWH. Among MWH, 58.6% were susceptible to HBV infection. There was a significant difference in the rate of lifetime exposure to HBV in MWH compared with NMWH (odds ratio [OR], 3.17; 95% confidence interval [CI], 1.64 to 6.13). However, there was no significant difference between participant groups with respect to current HBV infection (OR, 0.53; 95%CI, 0.07 to 3.86) or anti-HCV (OR, 0.54; 95%CI, 0.03 to 8.69). Age older than 40 years and working in a hospital laundry were independent predictors of lifetime exposure to HBV infection. Eleven (7.2%) respondents were vaccinated against HBV. CONCLUSIONS: Lifetime exposure to HBV infection was significantly higher in MWH than in NMWH. The majority of MWH was not vaccinated against HBV and thus remains susceptible to contracting the infection. Screening upon hire followed by vaccination of MWH is recommended to reduce the transmission of HBV. PMID:26797221

  2. Exposure to Low Irradiances Favors the Synthesis of 9-cis β,β-Carotene in Dunaliella salina (Teod.)1

    PubMed Central

    Orset, Sandra Charlotte; Young, Andrew John

    2000-01-01

    We examined the effect of irradiance on the synthesis of β-carotene and its isomers by Dunaliella salina. Growth irradiance had a marked effect both on growth of the alga (which was suppressed at both low and high irradiances) and on the accumulation of β-carotene. The accumulation of β-carotene but not α-carotene was closely linked to an increase in irradiance. Growth at low irradiances (20–50 μmol m−2 s−1) promoted a high ratio of 9-cis to all-trans β-carotene (>2:1), while exposure to high irradiances (200–1,250 μmol m−2 s−1) resulted in a large reduction in this ratio (to <0.45:1). A similar pattern was seen for the geometric isomers of α-carotene, with exposure to low irradiance favoring the accumulation of the 9-cis form. The carotenoid biosynthesis inhibitors 4-chloro-5(methylamino)-2-(α-α-α-trifluoro-m-tolyl)-3-(sH)-pyridazinone and 2-(4-chlorophenylthio)triethylamine caused the accumulation of the precursors phytoene and lycopene, respectively, in D. salina. High-performance liquid chromatography and infrared analysis showed that phytoene adopted the 15-cis and all-trans forms (as in higher plants), and that lycopene primarily adopted the all-trans form. This indicates that isomerization of β-carotene takes place during or after cyclization. PMID:10677453

  3. Gestational exposure to methylmercury and n-3 fatty acids: effects on high- and low-rate operant behavior in adulthood.

    PubMed

    Paletz, Elliott M; Craig-Schmidt, Margaret C; Newland, M Christopher

    2006-01-01

    Fish in the diet is the major source of methylmercury (MeHg) exposure, but eating fish also provides important nutrients. Many fish species contain essential long chain polyunsaturated fatty acids, especially docosahexaenoic acid (DHA), an omega-3 (or n-3) fatty acid, that is important for neural development and function. To examine interactions between MeHg and n-3 fatty acids, female Long-Evans rats were exposed, in utero, to 0, 0.5, or 5 ppm MeHg via drinking water, approximating exposures of 0, 40, and 400 mug/kg/day. They also received pre- and postnatal exposure to a diet containing either fish oil or coconut oil, creating a 2 (Diet)x3 (MeHg) full factorial design, with 6-8 rats per cell. The diets were high or marginal, respectively, in n-3 fatty acids but approximately equal in n-6 fatty acids. No exposure-related effects on developmental milestones or growth were noted. Behavior was evaluated using a series of rapidly increasing fixed ratio (FR) schedules of sucrose reinforcement; 1, 5, 25 and 75 lever presses were required for sucrose delivery, with three sessions provided at each requirement. This phase was followed by four sessions of a differential-reinforcement-of-low-rate-behavior (DRL) schedule, in which presses preceded by 10 s (or more) without a press were reinforced. Subsequently, several progressive ratio (PR) schedules that increased response requirements throughout a single session by a rate of 5%, 10%, or 20% were imposed. Rats exposed during gestation to MeHg had significantly higher response rates than controls under the large FR schedules, during the first session of DRL, and the PR 5% schedule, but neither fish oil nor coconut oil modified MeHg's effects. This finding is consistent with hypotheses that developmental MeHg exposure produced perseverative responding or altered the sensitivity of behavior to its reinforcing consequences and that certain reinforcement contingencies can unmask MeHg's effects.

  4. The rate of synthesis and decomposition of tissue proteins in hypokinesia and increased muscular activity

    NASA Technical Reports Server (NTRS)

    Fedorov, I. V.; Chernyy, A. V.; Fedorov, A. I.

    1978-01-01

    During hypokinesia and physical loading (swimming) of rats, the radioactivity of skeletal muscle, liver, kidney, heart, and blood proteins was determined after administration of radioactive amino acids. Tissue protein synthesis decreased during hypokinesia, and decomposition increased. Both synthesis and decomposition increased during physical loading, but anabolic processes predominated in the total tissue balance. The weights of the animals decreased in hypokinesia and increased during increased muscle activity.

  5. Exposure to monomethylarsonous acid (MMA{sup III}) leads to altered selenoprotein synthesis in a primary human lung cell model

    SciTech Connect

    Meno, Sarah R.; Nelson, Rebecca; Hintze, Korry J.; Self, William T.

    2009-09-01

    Monomethylarsonous acid (MMA{sup III}), a trivalent metabolite of arsenic, is highly cytotoxic and recent cell culture studies suggest that it might act as a carcinogen. The general consensus of studies indicates that the cytotoxicity of MMA{sup III} is a result of increased levels of reactive oxygen species (ROS). A longstanding relationship between arsenic and selenium metabolism has led to the use of selenium as a supplement in arsenic exposed populations, however the impact of organic arsenicals (methylated metabolites) on selenium metabolism is still poorly understood. In this study we determined the impact of exposure to MMA{sup III} on the regulation of expression of TrxR1 and its activity using a primary lung fibroblast line, WI-38. The promoter region of the gene encoding the selenoprotein thioredoxin reductase 1 (TrxR1) contains an antioxidant responsive element (ARE) that has been shown to be activated in the presence of electrophilic compounds. Results from radiolabeled selenoproteins indicate that exposure to low concentrations of MMA{sup III} resulted in increased synthesis of TrxR1 in WI-38 cells, and lower incorporation of selenium into other selenoproteins. MMA{sup III} treatment led to increased mRNA encoding TrxR1 in WI-38 cells, while lower levels of mRNA coding for cellular glutathione peroxidase (cGpx) were detected in exposed cells. Luciferase activity of TrxR1 promoter fusions increased with addition of MMA{sup III}, as did expression of a rat quinone reductase (QR) promoter fusion construct. However, MMA{sup III} induction of the TRX1 promoter fusion was abrogated when the ARE was mutated, suggesting that this regulation is mediated via the ARE. These results indicate that MMA{sup III} alters the expression of selenoproteins based on a selective induction of TrxR1, and this response to exposure to organic arsenicals that requires the ARE element.

  6. Insecticidal efficacy of abamectin against three stored-product insect pests: influence of dose rate, temperature, commodity, and exposure interval.

    PubMed

    Kavallieratos, Nickolas G; Athanassiou, Christos G; Vayias, Basileios J; Mihail, Spyridon B; Tomanović, Zeljko

    2009-06-01

    The insecticidal efficacy of abamectin against adults of Rhyzopertha dominica (F.), Sitophilus oryzae (L.), and Tribolium confusum Jacquelin du Val was assessed under laboratory conditions. The efficacy of abamectin was assessed on two commodities (wheat, Triticum aestivum L. and maize, Zea mays L.) and two temperatures (25 and 30 degrees C). The dose rates used were 0.01, 0.1, 0.5, and 1 ppm. Mortality of the exposed adults in the treated grains was measured after 7, 14 and 21 d (= days), whereas progeny production was assessed 60 d later. Increase of dose rate, exposure interval, and temperature enhanced the efficacy of abamectin. Noticeable mortality was noted for all species after 21 d of exposure, although for S. oryzae, mortality was very high even at 7 d. For dose rates higher than 0.5 ppm, the efficacy of abamectin was higher in maize than in wheat against all species tested. Finally, progeny production was measured for all three species on commodities treated with 0.01 and 0.1 ppm of abamectin.

  7. Modeling exposure close to air pollution sources in naturally ventilated residences: association of turbulent diffusion coefficient with air change rate.

    PubMed

    Cheng, Kai-Chung; Acevedo-Bolton, Viviana; Jiang, Ruo-Ting; Klepeis, Neil E; Ott, Wayne R; Fringer, Oliver B; Hildemann, Lynn M

    2011-05-01

    For modeling exposure close to an indoor air pollution source, an isotropic turbulent diffusion coefficient is used to represent the average spread of emissions. However, its magnitude indoors has been difficult to assess experimentally due to limitations in the number of monitors available. We used 30-37 real-time monitors to simultaneously measure CO at different angles and distances from a continuous indoor point source. For 11 experiments involving two houses, with natural ventilation conditions ranging from <0.2 to >5 air changes per h, an eddy diffusion model was used to estimate the turbulent diffusion coefficients, which ranged from 0.001 to 0.013 m² s⁻¹. The model reproduced observed concentrations with reasonable accuracy over radial distances of 0.25-5.0 m. The air change rate, as measured using a SF₆ tracer gas release, showed a significant positive linear correlation with the air mixing rate, defined as the turbulent diffusion coefficient divided by a squared length scale representing the room size. The ability to estimate the indoor turbulent diffusion coefficient using two readily measurable parameters (air change rate and room dimensions) is useful for accurately modeling exposures in close proximity to an indoor pollution source.

  8. DNA repair synthesis in the rat retina following in vivo exposure to 300-nm radiation

    SciTech Connect

    Rapp, L.M.; Jose, J.G.; Pitts, D.G.

    1985-03-01

    Quantitative autoradiography was used to study the incorporation of /sup 3/H-thymidine into the retina of albino rats following in vivo exposure to 300-nm radiation. Relative to background labeling in unexposed eyes, there was 8-20 times as much label per unit area in the outer nuclear layer, inner nuclear layer, and ganglion cells of 300-nm exposed retinas. The photoreceptor inner segments also showed thymidine labeling in both control and exposed retinas.

  9. Synthesis of low molecular weight thiols in response to Cd exposure in Thlaspi caerulescens.

    PubMed

    Hernández-Allica, J; Garbisu, C; Becerril, J M; Barrutia, O; García-Plazaola, J I; Zhao, F J; Mcgrath, S P

    2006-07-01

    In this study, we investigated the accumulation of phytochelatins (PCs) and other low molecular weight (LMW) thiols in response to Cd exposure in two contrasting ecotypes differing in Cd accumulation. Using a root elongation test, we found that the highly accumulating ecotype Ganges was more tolerant to Cd than the low Cd-accumulation ecotype Prayon. L-buthionine-(S,R)-sulphoximine (BSO), a potent inhibitor of the gamma-glutamylcysteine synthetase gamma-ECS) (an enzyme involved in the PC biosynthetic pathway), increased the Cd sensitivity of Prayon, but had no effect on Ganges. Although PC accumulation increased in response to Cd exposure, no significant differences were observed between the two ecotypes. Cd exposure induced a dose-dependent accumulation of both Cys and a still unidentified LMW thiol in roots of both ecotypes. Root accumulation of Cys and this thiol was higher in Ganges than in Prayon; the ecotypic differences were more pronounced when the plants were treated with BSO. These findings suggest that PCs do not contribute to the Cd hypertolerance displayed by the Ganges ecotype of Thlaspi caerulescens, whereas Cys and other LMW thiols might be involved. PMID:17080963

  10. Exposure to the water soluble fraction of crude oil or to naphthalenes alters breathing rates in Gulf killifish, Fundulus grandis

    SciTech Connect

    Russell, L.C.; Fingerman, M.

    1984-03-01

    Alteration in breathing rate has been used to monitor the effects of pollutants on fishes. Particularly pertinent to the study described herein are the observations that the water soluble fractions (WSF) from Cook Inlet crude oil, Prudhoe Bay crude oil and No. 2 fuel oil increased the breathing rate of pink salmon, Oncorhynchus gorbuscha, fry. However, possible underlying neurological mechanisms for this response have not been identified. Pollutant-induced changes in a fish's breathing rate may indicate neurochemical imbalances in the brain. Exposure of the longnose killifish, Fundulus similis, to the WSF of petroleum resulted in accumulation of naphthalenes from this WSF in high levels in the brain. Various organic compounds have been found to ultimately produce reductions in the whole brain concentration of dopamine in fishes. In view of these effects of various pollutants on breathing rate and the brain dopamine level in fishes, experiments were performed to determine the effects of (a) the WSF of South Louisiana crude oil, (b) two of its most toxic components (naphthalene and 2,6-dimethylnaphthalene) and (c) the dopamine precursor, L-DOPA, on the breathing rate of Fundulus grandis. These experiments would not only reveal whether the WSF and naphthalenes affect the breathing rate but also whether it might be affected by the dopamine concentration in the fish.

  11. Mechanistic role of water on the rate and selectivity of Fischer-Tropsch synthesis on ruthenium catalysts.

    PubMed

    Hibbitts, David D; Loveless, Brett T; Neurock, Matthew; Iglesia, Enrique

    2013-11-18

    Water increases Fischer-Tropsch synthesis (FTS) rates on Ru through H-shuttling processes. Chemisorbed hydrogen (H*) transfers its electron to the metal and protonates the O-atom of CO* to form COH*, which subsequently hydrogenates to *HCOH* in the kinetically relevant step. H2 O also increases the chain length of FTS products by mediating the H-transfer steps during reactions of alkyl groups with CO* to form longer-chain alkylidynes and OH*.

  12. Stress, temperature, heart rate, and hibernating factors in hamsters. [pathophysiological conditions resulting from exposure to zero gravity

    NASA Technical Reports Server (NTRS)

    Musacchia, X. J.

    1974-01-01

    Pathophysiological conditions resulting from prolonged exposure to zero gravity, cabin constraint, altered ambient environment, whether it be noise, vibrations, high temperatures, or combinations of such factors, are studied in laboratory animals and applied to manned space flight. Results and plans for further study are presented. Specific topics covered include: thermoregulation and its role in reflecting stress and adaptation to the gravity free environment and cabin confinement with its altered circadian forcings; renal function and its measurement in electrolyte distribution and blood flow dynamics; gastronintestinal function and an assessment of altered absorptive capacity in the intestinal mucosa; and catecholamine metabolism in terms of distribution and turnover rates in specific tissues.

  13. EXPOSURE TO CONCENTRATED AMBIENT PARTICLES IN DETROIT ALTERS HEART RATE VARIABILITY IN SPONTANEOUSLY HYPERTENSIVE RATS

    EPA Science Inventory

    Elevations in airborne particulate matter (PM) are linked to increased mortality and morbidity in humans with cardiopulmonary disease. Clinical studies show that PM is associated with altered heart rate variability (HRV) and suggests that loss of autonomic control may underlie ca...

  14. Outgassing rate of preconditioned vacuum systems after short exposure to the atmosphere: Outgassing rate measurements on Viton-A and copper

    SciTech Connect

    Dayton, B.B.

    1995-03-01

    When the sorption and desorption rates depend primarily on the diffusion of water vapor and atmospheric gases through the bulk of the sorbent (which may be an elastomer or plastic) and the process is reversible, then by an application of Fick`s law and Duhamel`s theorem equations can be derived for the outgassing rate as a function of time during subsequent pumpdowns in terms of the time of exposure to atmosphere with known relative humidity and the outgassing rate as a function of time during the initial conditioning cycle. Good agreement with the predictions of these equations has been obtained from measurements of repeated pumpdowns of a large-area sample of a Viton-A elastomer. However, similar experiments on copper plates showed relatively poor agreement with the theoretical equations indicating that the sorption--desorption process for water vapor in the oxide layer on metal surfaces may not be exactly reversible or that the process is not strictly controlled by diffusion. {copyright} {ital 1995} {ital American} {ital Vacuum} {ital Society}

  15. Evaluation of coral pathogen growth rates after exposure to atmospheric African dust samples

    USGS Publications Warehouse

    Lisle, John T.; Garrison, Virginia H.; Gray, Michael A.

    2014-01-01

    Laboratory experiments were conducted to assess if exposure to atmospheric African dust stimulates or inhibits the growth of four putative bacterial coral pathogens. Atmospheric dust was collected from a dust-source region (Mali, West Africa) and from Saharan Air Layer masses over downwind sites in the Caribbean [Trinidad and Tobago and St. Croix, U.S. Virgin Islands (USVI)]. Extracts of dust samples were used to dose laboratory-grown cultures of four putative coral pathogens: Aurantimonas coralicida (white plague type II), Serratia marcescens (white pox), Vibrio coralliilyticus, and V. shiloi (bacteria-induced bleaching). Growth of A. coralicida and V. shiloi was slightly stimulated by dust extracts from Mali and USVI, respectively, but unaffected by extracts from the other dust sources. Lag time to the start of log-growth phase was significantly shortened for A. coralicida when dosed with dust extracts from Mali and USVI. Growth of S. marcescens and V. coralliilyticus was neither stimulated nor inhibited by any of the dust extracts. This study demonstrates that constituents from atmospheric dust can alter growth of recognized coral disease pathogens under laboratory conditions.

  16. BPA exposure during in vitro oocyte maturation results in dose-dependent alterations to embryo development rates, apoptosis rate, sex ratio and gene expression.

    PubMed

    Ferris, Jacqueline; Mahboubi, Kiana; MacLusky, Neil; King, W Allan; Favetta, Laura A

    2016-01-01

    Alterations in the oocyte's environment can negatively affect embryo development. Oocyte quality, which can determine embryonic viability, is easily perturbed, thus factors affecting normal oocyte maturation are a concern. Bisphenol A (BPA) is an endocrine disrupting chemical that elicits a variety of reproductive effects. BPA has previously been found to disrupt meiosis, however the embryonic effects in mammals are not well documented. Here, bovine oocytes were matured in vitro with and without BPA treatment. Resulting embryos exhibited decreased embryonic development rates, increased apoptosis, and a skewed sex ratio. Gene expression in blastocysts was not altered, whereas treatment with 15ng/mL BPA resulted in increased expression of several of the genes studies, however this increase was largely due to a vehicle effect. BPA exposure during oocyte maturation in vitro can therefore, in a dose-dependent way, decrease oocyte and embryo quality and developmental potential and affect gene expression of developmentally important transcripts.

  17. Simultaneous Hypoxia and Low Extracellular pH Suppress Overall Metabolic Rate and Protein Synthesis In Vitro

    PubMed Central

    Sørensen, Brita Singers; Busk, Morten; Overgaard, Jens; Horsman, Michael R.; Alsner, Jan

    2015-01-01

    Background The tumor microenvironment is characterized by regions of hypoxia and acidosis which are linked to poor prognosis. This occurs due to an aberrant vasculature as well as high rates of glycolysis and lactate production in tumor cells even in the presence of oxygen (the Warburg effect), which weakens the spatial linkage between hypoxia and acidosis. Methods Five different human squamous cell carcinoma cell lines (SiHa, FaDuDD, UTSCC5, UTSCC14 and UTSCC15) were treated with hypoxia, acidosis (pH 6.3), or a combination, and gene expression analyzed using microarray. SiHa and FaDuDD were chosen for further characterization of cell energetics and protein synthesis. Total cellular ATP turnover and relative glycolytic dependency was determined by simultaneous measurements of oxygen consumption and lactate synthesis rates and total protein synthesis was determined by autoradiographic quantification of the incorporation of 35S-labelled methionine and cysteine into protein. Results Microarray analysis allowed differentiation between genes induced at low oxygen only at normal extracellular pH (pHe), genes induced at low oxygen at both normal and low pHe, and genes induced at low pHe independent of oxygen concentration. Several genes were found to be upregulated by acidosis independent of oxygenation. Acidosis resulted in a more wide-scale change in gene expression profiles than hypoxia including upregulation of genes involved in the translation process, for example Eukaryotic translation initiation factor 4A, isoform 2 (EIF4A2), and Ribosomal protein L37 (RPL37). Acidosis suppressed overall ATP turnover and protein synthesis by 50%. Protein synthesis, but not total ATP production, was also suppressed under hypoxic conditions. A dramatic decrease in ATP turnover (SiHa) and protein synthesis (both cell lines) was observed when hypoxia and low pHe were combined. Conclusions We demonstrate here that the influence of hypoxia and acidosis causes different responses, both

  18. The characteristics of coarse particulate matter air pollution associated with alterations in blood pressure and heart rate during controlled exposures

    PubMed Central

    Morishita, Masako; Bard, Robert L.; Wang, Lu; Das, Ritabrata; Dvonch, J. Timothy; Spino, Catherine; Mukherjee, Bhramar; Sun, Qinghua; Harkema, Jack R.; Rajagopalan, Sanjay; Brook, Robert D.

    2015-01-01

    Although fine particulate matter (PM) air pollution <2.5 μm in aerodynamic diameter (PM2.5) is a leading cause of global morbidity and mortality, the potential health effects of coarse PM (2.5–10 μm in aerodynamic diameter; PM10–2.5) remain less clearly understood. We aimed to elucidate the components within coarse PM most likely responsible for mediating these hemodynamic alterations. Thirty-two healthy adults (25.9 ± 6.6 years) were exposed to concentrated ambient coarse PM (CAP) (76.2 ± 51.5 μg/m3) and filtered air (FA) for 2 h in a rural location in a randomized double-blind crossover study. The particle constituents (24 individual elements, organic and elemental carbon) were analyzed from filter samples and associated with the blood pressure (BP) and heart rate (HR) changes occurring throughout CAP and FA exposures in mixed model analyses. Total coarse PM mass along with most of the measured elements were positively associated with similar degrees of elevations in both systolic BP and HR. Conversely, total PM mass was unrelated, whereas only two elements (Cu and Mo) were positively associated with and Zn was inversely related to diastolic BP changes during exposures. Inhalation of coarse PM from a rural location rapidly elevates systolic BP and HR in a concentration-responsive manner, whereas the particulate composition does not appear to be an important determinant of these responses. Conversely, exposure to certain PM elements may be necessary to trigger a concomitant increase in diastolic BP. These findings suggest that particulate mass may be an adequate metric of exposure to predict some, but not all, hemodynamic alterations induced by coarse PM mass. PMID:25227729

  19. The solar exposure time required for vitamin D3 synthesis in the human body estimated by numerical simulation and observation in Japan.

    PubMed

    Miyauchi, Masaatsu; Hirai, Chizuko; Nakajima, Hideaki

    2013-01-01

    Although the importance of solar radiation for vitamin D3 synthesis in the human body is well known, the solar exposure time required to prevent vitamin D deficiency has not been determined in Japan. This study attempted to identify the time of solar exposure required for vitamin D3 synthesis in the body by season, time of day, and geographic location (Sapporo, Tsukuba, and Naha) using both numerical simulations and observations. According to the numerical simulation for Tsukuba at noon in July under a cloudless sky, 3.5 min of solar exposure are required to produce 5.5 μg vitamin D3 per 600 cm2 skin corresponding to the area of a face and the back of a pair of hands without ingestion from foods. In contrast, it took 76.4 min to produce the same quantity of vitamin D3 at Sapporo in December, at noon under a cloudless sky. The necessary exposure time varied considerably with the time of the day. For Tsukuba at noon in December, 22.4 min were required, but 106.0 min were required at 09:00 and 271.3 min were required at 15:00 for the same meteorological conditions. Naha receives high levels of ultraviolet radiation allowing vitamin D3 synthesis almost throughout the year.

  20. Concentrations of polybromobiphenyls and polybromodiphenyl ethers in home dust: relevance to socio-economic status and human exposure rate.

    PubMed

    Kefeni, Kebede K; Okonkwo, Jonathan O; Botha, Ben M

    2014-02-01

    This study reports on the levels of all major polybromobiphenyls (PBBs) and polybromodiphenyl ethers (PBDEs) in 31 home dust samples collected in Pretoria, South Africa. Low concentrations of PBB and PBDE congeners were detected in 21 and 7 samples, respectively. The Σ10PBDEs concentration ranged from <0.3 to 234 ng g(-1) dry weight (dw) of dust with a median of 18.3 ng g(-1) dw. No significant differences in the total concentration of PBDEs were observed among three socio-economic categories considered. The overall daily intake of PBDEs via ingestion of dust was estimated for children and adults using median concentrations of Σ10PBDEs. Accordingly, for children and adults the exposure rate values are 0.96 and 0.38 ng day(-1), respectively. In addition, the estimated daily dust ingestion exposure rate doses for children and adults with respect to BDE-47 and BDE-99 were by far lower than the reference dose values. It can, therefore, be said that South Africans living in Pretoria are exposed to low concentrations of PBDEs from home environment dust. PMID:24252199

  1. The rate of X-ray-induced DNA double-strand break repair in the embryonic mouse brain is unaffected by exposure to 50 Hz magnetic fields

    PubMed Central

    Woodbine, Lisa; Haines, Jackie; Coster, Margaret; Barazzuol, Lara; Ainsbury, Elizabeth; Sienkiewicz, Zenon; Jeggo, Penny

    2015-01-01

    Abstract Purpose: Following in utero exposure to low dose radiation (10–200 mGy), we recently observed a linear induction of DNA double-strand breaks (DSB) and activation of apoptosis in the embryonic neuronal stem/progenitor cell compartment. No significant induction of DSB or apoptosis was observed following exposure to magnetic fields (MF). In the present study, we exploited this in vivo system to examine whether exposure to MF before and after exposure to 100 mGy X-rays impacts upon DSB repair rates. Materials and methods: 53BP1 foci were quantified following combined exposure to radiation and MF in the embryonic neuronal stem/progenitor cell compartment. Embryos were exposed in utero to 50 Hz MF at 300 μT for 3 h before and up to 9 h after exposure to 100 mGy X-rays. Controls included embryos exposed to MF or X-rays alone plus sham exposures. Results: Exposure to MF before and after 100 mGy X-rays did not impact upon the rate of DSB repair in the embryonic neuronal stem cell compartment compared to repair rates following radiation exposure alone. Conclusions: We conclude that in this sensitive system MF do not exert any significant level of DNA damage and do not impede the repair of X-ray induced damage. PMID:25786477

  2. The effects of strong shock waves on mortality rates and percentages of pulmonary lesions in rats as a function of the number of exposures

    NASA Technical Reports Server (NTRS)

    Vassout, P.; Parmentier, G.

    1978-01-01

    The results of the study reveal that with regard to the pulmonary lesions, twice the number of exposures is compensated for by quartering the overpressure of the wave crest. With regard to the mortality rates, it reveals that halving the overpressure of the wave crest is offset by a 20-fold increase in the number of exposures.

  3. Mechanical properties of methacrylate-based model dentin adhesives: effect of loading rate and moisture exposure.

    PubMed

    Singh, Viraj; Misra, Anil; Parthasarathy, Ranganathan; Ye, Qiang; Park, Jonggu; Spencer, Paulette

    2013-11-01

    The aim of this study is to investigate the mechanical behavior of model methacrylate-based dentin adhesives under conditions that simulate the wet oral environment. A series of monotonic and creep experiments were performed on rectangular beam samples of dentin adhesive in three-point bending configuration under different moisture conditions. The monotonic test results show a significant effect of loading rate on the failure strength and the linear limit (yield point) of the stress-strain response. In addition, these tests show that the failure strength is low, and the failure occurs at a smaller deformation when the test is performed under continuously changing moisture conditions. The creep test results show that under constant moisture conditions, the model dentin adhesives can have a viscoelastic response under certain low loading levels. However, when the moisture conditions vary under the same low loading levels, the dentin adhesives have an anomalous creep response accompanied by large secondary creep and high strain accumulation. PMID:23744598

  4. Rates of Fetal Polydrug Exposures in Methadone-Maintained Pregnancies from a High-Risk Population

    PubMed Central

    Delano, Kaitlyn; Gareri, Joey; Koren, Gideon

    2013-01-01

    Methadone maintenance treatment (MMT) is the standard of care during pregnancy for opioid-dependency, showing efficacy in improving prenatal care and reducing risk of relapse. By design, however, MMT is only intended to prevent withdrawal thus facilitating cognitive behavioural interventions. In order to maximize the benefits of MMT, it is essential that methadone is both properly prescribed and that additional addiction treatment is concurrently administered. This study aims to determine the effectiveness of MMT engagement in high-risk pregnant women in reducing polydrug use by objective laboratory examination of neonatal meconium. Patients and Methods Over a 29-month period, the Motherisk Laboratory at the Hospital for Sick Children in Toronto analyzed meconium samples as per request by social services and hospitals for drugs of abuse. Results Of the 904 meconium samples received, 273 were tested for methadone with 164 positive and 109 negative for methadone. Almost half of the methadone positive samples (46.34%) were also positive for at least one other opioid compound, which did not differ statistically from the methadone-negative control samples (46.79%; Chi square test, p=0.94). No differences were found between the methadone positive and negative groups in rates of concurrent amphetamines, cocaine, cannabis, and alcohol use indicating a similar risk of polydrug use between pregnant women taking or not taking methadone in this population. Discussion The high rates of additional opioid and other drug use in the MMT group, suggest that MMT is failing this population of patients. It is possible that methadone doses during pregnancy are not appropriately adjusted for changes in pharmacokinetic parameters (e.g. blood volume, renal function) during the second and third trimesters. This may result in sub-therapeutic dosing creating withdrawal symptoms leading to additional substance use. Alternatively, these results may be demonstrating a substantial lack in

  5. Continuous multigram nanoparticle synthesis by high-power, high-repetition-rate ultrafast laser ablation in liquids.

    PubMed

    Streubel, René; Barcikowski, Stephan; Gökce, Bilal

    2016-04-01

    Utilizing a novel laser system consisting of a 500 W, 10 MHz, 3 ps laser source which is fully synchronized with a polygon scanner reaching scanning speeds up to 500 m/s, we explore the possibilities to increase the productivity of nanoparticle synthesis by laser ablation in liquids. By exploiting the high scanning speed, laser-induced cavitation bubbles are spatially bypassed at high repetition rates and continuous multigram ablation rates up to 4 g/h are demonstrated for platinum, gold, silver, aluminum, copper, and titanium. Furthermore, the applicable, ablation-effective repetition rate is increased by two orders of magnitude. The ultrafast ablation mechanisms are investigated for different laser fluences, repetition rates, interpulse distances, and ablation times, while the resulting trends are successfully described by validating a model developed for ultrafast laser ablation in air to hold in liquids as well. PMID:27192268

  6. In vivo rates of erythrocyte glutathione synthesis in adults with sickle cell disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Despite reports of lower GSH concentration in sickle cell disease (SCD), the in vivo kinetic mechanism(s) responsible for GSH deficiency is unknown. To determine whether suppressed synthesis was responsible for the lower erythrocyte GSH concentration, we used a primed intermittent infusion of [(2)H(...

  7. Long-term exposure of proximal tubular epithelial cells to glucose induces transforming growth factor-beta 1 synthesis via an autocrine PDGF loop.

    PubMed

    Fraser, Donald; Brunskill, Nigel; Ito, Takafumi; Phillips, Aled

    2003-12-01

    We have recently reported increased transforming growth factor (TGF)-beta1 gene transcription in proximal tubular cells within 12 hours of exposure to 25 mmol/L D-glucose, with a requirement for a second stimulus such as platelet-derived growth factor (PDGF) to increase its translation in short-term experiments. In the current study we investigated the effect on TGF-beta 1 production of prolonged exposure of proximal tubular cells to high glucose concentrations. Enzyme-linked immunosorbent assay of cell culture supernatant showed significant increase in latent TGF-beta 1 only after 7 days exposure to high glucose. Radiolabeling of glucose-stimulated cells with (3)H amino acids and subsequent immunoprecipitation of TGF-beta 1 demonstrated de novo synthesis from day 5 of high glucose exposure onwards. Similarly, polysome analysis showed enhanced translation of TGF-beta mRNA after 4 or more days of high glucose exposure. TGF-beta 1 synthesis, following addition of glucose, was inhibited by blockade of the PDGF-alpha receptor subunit. Glucose did not alter PDGF expression, nor expression of PDGF alpha-receptors. Activation of the receptor following addition of 25 mm D-glucose could be demonstrated suggesting increased sensitivity to endogenous PDGF. Exposure to glucose activated p38MAP kinase, and inhibition of this activation abrogated both glucose induced TGF-beta 1 transcriptional activation and TGF-beta 1 synthesis. Inhibition of p38MAP kinase did not influence the effect of exogenous PDGF when cells were stimulated sequentially by glucose and PDGF. We postulate that glucose induces an early increase in TGF-beta 1 transcription via activation of p38MAP kinase. In addition, glucose causes a late increase in PDGF-dependent TGF-beta 1 translation by enhancing cellular sensitivity to PDGF. This provides a potential explanation for the clinical observation that prolonged poor glycemic control may contribute to progression of diabetic nephropathy. PMID:14633628

  8. Individuals Maintain Similar Rates of Protein Synthesis over Time on the Same Plane of Nutrition under Controlled Environmental Conditions

    PubMed Central

    McCarthy, Ian D.; Owen, Stewart F.; Watt, Peter W.; Houlihan, Dominic F.

    2016-01-01

    Consistent individual differences in animal performance drive individual fitness under variable environmental conditions and provide the framework through which natural selection can operate. Underlying this concept is the assumption that individuals will display consistent levels of performance in fitness-related traits and interest has focused on individual variation and broad sense repeatability in a range of behavioural and physiological traits. Despite playing a central role in maintenance and growth, and with considerable inter-individual variation documented, broad sense repeatability in rates of protein synthesis has not been assessed. In this study we show for the first time that juvenile flounder Platichthys flesus reared under controlled environmental conditions on the same plane of nutrition for 46 days maintain consistent whole-animal absolute rates of protein synthesis (As). By feeding meals containing 15N-labelled protein and using a stochastic end-point model, two non-terminal measures of protein synthesis were made 32 days apart (d14 and d46). As values (mass-corrected to a standard mass of 12 g) showed 2- to 3-fold variation between individuals on d14 and d46 but individuals showed similar As values on both days with a broad sense repeatability estimate of 0.684 indicating significant consistency in physiological performance under controlled experimental conditions. The use of non-terminal methodologies in studies of animal ecophysiology to make repeat measures of physiological performance enables known individuals to be tracked across changing conditions. Adopting this approach, repeat measures of protein synthesis under controlled conditions will allow individual ontogenetic changes in protein metabolism to be assessed to better understand the ageing process and to determine individual physiological adaptive capacity, and associated energetic costs of adaptation, to global environmental change. PMID:27018996

  9. Individuals Maintain Similar Rates of Protein Synthesis over Time on the Same Plane of Nutrition under Controlled Environmental Conditions.

    PubMed

    McCarthy, Ian D; Owen, Stewart F; Watt, Peter W; Houlihan, Dominic F

    2016-01-01

    Consistent individual differences in animal performance drive individual fitness under variable environmental conditions and provide the framework through which natural selection can operate. Underlying this concept is the assumption that individuals will display consistent levels of performance in fitness-related traits and interest has focused on individual variation and broad sense repeatability in a range of behavioural and physiological traits. Despite playing a central role in maintenance and growth, and with considerable inter-individual variation documented, broad sense repeatability in rates of protein synthesis has not been assessed. In this study we show for the first time that juvenile flounder Platichthys flesus reared under controlled environmental conditions on the same plane of nutrition for 46 days maintain consistent whole-animal absolute rates of protein synthesis (As). By feeding meals containing 15N-labelled protein and using a stochastic end-point model, two non-terminal measures of protein synthesis were made 32 days apart (d14 and d46). As values (mass-corrected to a standard mass of 12 g) showed 2- to 3-fold variation between individuals on d14 and d46 but individuals showed similar As values on both days with a broad sense repeatability estimate of 0.684 indicating significant consistency in physiological performance under controlled experimental conditions. The use of non-terminal methodologies in studies of animal ecophysiology to make repeat measures of physiological performance enables known individuals to be tracked across changing conditions. Adopting this approach, repeat measures of protein synthesis under controlled conditions will allow individual ontogenetic changes in protein metabolism to be assessed to better understand the ageing process and to determine individual physiological adaptive capacity, and associated energetic costs of adaptation, to global environmental change. PMID:27018996

  10. Regional bit allocation and rate distortion optimization for multiview depth video coding with view synthesis distortion model.

    PubMed

    Zhang, Yun; Kwong, Sam; Xu, Long; Hu, Sudeng; Jiang, Gangyi; Kuo, C-C Jay

    2013-09-01

    In this paper, we propose a view synthesis distortion model (VSDM) that establishes the relationship between depth distortion and view synthesis distortion for the regions with different characteristics: color texture area corresponding depth (CTAD) region and color smooth area corresponding depth (CSAD), respectively. With this VSDM, we propose regional bit allocation (RBA) and rate distortion optimization (RDO) algorithms for multiview depth video coding (MDVC) by allocating more bits on CTAD for rendering quality and fewer bits on CSAD for compression efficiency. Experimental results show that the proposed VSDM based RBA and RDO can improve the coding efficiency significantly for the test sequences. In addition, for the proposed overall MDVC algorithm that integrates VSDM based RBA and RDO, it achieves 9.99% and 14.51% bit rate reduction on average for the high and low bit rate, respectively. It can improve virtual view image quality 0.22 and 0.24 dB on average at the high and low bit rate, respectively, when compared with the original joint multiview video coding model. The RD performance comparisons using five different metrics also validate the effectiveness of the proposed overall algorithm. In addition, the proposed algorithms can be applied to both INTRA and INTER frames.

  11. Impact of head morphology on local brain specific absorption rate from exposure to mobile phone radiation.

    PubMed

    Adibzadeh, Fatemeh; Bakker, Jurriaan F; Paulides, Margarethus M; Verhaart, René F; van Rhoon, Gerard C

    2015-01-01

    Among various possible health effects of mobile phone radiation, the risk of inducing cancer has the strongest interest of laymen and health organizations. Recently, the Interphone epidemiological study investigated the association between the estimated Radio Frequency (RF) dose from mobile phones and the risk of developing a brain tumor. Their dosimetric analysis included over 100 phone models but only two homogeneous head phantoms. So, the potential impact of individual morphological features on global and local RF absorption in the brain was not investigated. In this study, we performed detailed dosimetric simulations for 20 head models and quantified the variation of RF dose in different brain regions as a function of head morphology. Head models were exposed to RF fields from generic mobile phones at 835 and 1900 MHz in the "tilted" and "cheek" positions. To evaluate the local RF dose variation, we used and compared two different post-processing methods, that is, averaging specific absorption rate (SAR) over Talairach regions and over sixteen predefined 1 cm(3) cube-shaped field-sensors. The results show that the variation in the averaged SAR among the heads can reach up to 16.4 dB at a 1 cm(3) cube inside the brain (field-sensor method) and alternatively up to 15.8 dB in the medulla region (Talairach method). In conclusion, we show head morphology as an important uncertainty source for dosimetric studies of mobile phones. Therefore, any dosimetric analysis dealing with RF dose at a specific region in the brain (e.g., tumor risk analysis) should be based upon real morphology.

  12. Fast synthesis of high-quality reduced graphene oxide at room temperature under light exposure

    NASA Astrophysics Data System (ADS)

    Some, Surajit; Kim, Sungjin; Samanta, Khokan; Kim, Youngmin; Yoon, Yeoheung; Park, Younghun; Lee, Sae Mi; Lee, Keunsik; Lee, Hyoyoung

    2014-09-01

    An approach of presenting new reducing reagents, sodium-benzophenone (Na-B) or Na-B in the presence of the hydrazine (Na-B-H) system under light exposure could produce rGOs with/without N-doping at room temperature in both the solution phase and on a solid substrate. Benzophenone activated those solutions acting as a photosensitizer under light. It was assumed that the newly generated radical anions with electrons from Na-B under light can reduce GO to rGO sheets (rGONa-B1). In addition, the Na-B-H system can allow a higher degree of reduction with the doping of nitrogen atoms by the introduction of hydrazine to produce radical anions and electrons with a sodium hydrazide complex, which helps decrease the sheet resistance of the as-made rGONa-B-H2. The excellent properties (very low oxygen content (C/O ~16.2), and low sheet resistance (~130 Ω square-1)) of the rGOs were confirmed by XPS, XRD, IR, Raman spectroscopy, TGA, wettability, and sheet resistance measurements. High-quality rGO films on flexible substrates could be prepared by directly immersing the GO films in these solutions for several minutes.An approach of presenting new reducing reagents, sodium-benzophenone (Na-B) or Na-B in the presence of the hydrazine (Na-B-H) system under light exposure could produce rGOs with/without N-doping at room temperature in both the solution phase and on a solid substrate. Benzophenone activated those solutions acting as a photosensitizer under light. It was assumed that the newly generated radical anions with electrons from Na-B under light can reduce GO to rGO sheets (rGONa-B1). In addition, the Na-B-H system can allow a higher degree of reduction with the doping of nitrogen atoms by the introduction of hydrazine to produce radical anions and electrons with a sodium hydrazide complex, which helps decrease the sheet resistance of the as-made rGONa-B-H2. The excellent properties (very low oxygen content (C/O ~16.2), and low sheet resistance (~130 Ω square-1)) of the r

  13. Dietary mercury exposure causes decreased escape takeoff flight performance and increased molt rate in European starlings (Sturnus vulgaris).

    PubMed

    Carlson, Jenna R; Cristol, Daniel; Swaddle, John P

    2014-10-01

    Mercury is a widespread and persistent environmental contaminant that occurs in aquatic and terrestrial habitats. Recently, songbirds that forage from primarily terrestrial sources have shown evidence of bioaccumulation of mercury, but little research has assessed the effects of mercury on their health and fitness. There are many indications that mercury negatively affects neurological functioning, bioenergetics, and behavior through a variety of mechanisms and in a wide array of avian taxa. Effective flight is crucial to avian fitness and feather molt is an energetically expensive life history trait. Therefore, we investigated whether mercury exposure influenced flight performance and molt in a common songbird, the European starling (Sturnus vulgaris). Specifically, we dosed the diet of captive starlings with methylmercury cysteine at 0.0, 0.75, or 1.5 μg/g wet weight and recorded changes in flight performance after 1 year of dietary mercury exposure. We also recorded the annual molt of wing feathers. We found that individuals dosed with mercury exhibited decreased escape takeoff flight performance compared with controls and blood mercury was also correlated with an increased rate of molt, which can reduce flight performance and thermoregulatory ability. This study reveals two novel endpoints, flight performance and molt, that may be affected by dietary mercury exposure. These findings suggest a potential impact on wild songbirds exposed to mercury levels comparable to the high dosage levels in the present study. Any decrease in flight efficiency could reduce fitness due to a direct impact on survival during predation events or by decreased efficiency in other critical activities (such as foraging or migration) that require efficient flight. PMID:25030113

  14. Short-term muscle disuse lowers myofibrillar protein synthesis rates and induces anabolic resistance to protein ingestion.

    PubMed

    Wall, Benjamin T; Dirks, Marlou L; Snijders, Tim; van Dijk, Jan-Willem; Fritsch, Mario; Verdijk, Lex B; van Loon, Luc J C

    2016-01-15

    Disuse leads to rapid loss of skeletal muscle mass and function. It has been hypothesized that short successive periods of muscle disuse throughout the lifespan play an important role in the development of sarcopenia. The physiological mechanisms underlying short-term muscle disuse atrophy remain to be elucidated. We assessed the impact of 5 days of muscle disuse on postabsorptive and postprandial myofibrillar protein synthesis rates in humans. Twelve healthy young (22 ± 1 yr) men underwent a 5-day period of one-legged knee immobilization (full leg cast). Quadriceps cross-sectional area (CSA) of both legs was assessed before and after immobilization. Continuous infusions of l-[ring-(2)H5]phenylalanine and l-[1-(13)C]leucine were combined with the ingestion of a 25-g bolus of intrinsically l-[1-(13)C]phenylalanine- and l-[1-(13)C]leucine-labeled dietary protein to assess myofibrillar muscle protein fractional synthetic rates in the immobilized and nonimmobilized control leg. Immobilization led to a 3.9 ± 0.6% decrease in quadriceps muscle CSA of the immobilized leg. Based on the l-[ring-(2)H5]phenylalanine tracer, immobilization reduced postabsorptive myofibrillar protein synthesis rates by 41 ± 13% (0.015 ± 0.002 vs. 0.032 ± 0.005%/h, P < 0.01) and postprandial myofibrillar protein synthesis rates by 53 ± 4% (0.020 ± 0.002 vs. 0.044 ± 0.003%/h, P < 0.01). Comparable results were found using the l-[1-(13)C]leucine tracer. Following protein ingestion, myofibrillar protein bound l-[1-(13)C]phenylalanine enrichments were 53 ± 18% lower in the immobilized compared with the control leg (0.007 ± 0.002 and 0.015 ± 0.002 mole% excess, respectively, P < 0.05). We conclude that 5 days of muscle disuse substantially lowers postabsorptive myofibrillar protein synthesis rates and induces anabolic resistance to protein ingestion.

  15. A macroscopic and microscopic study of radon exposure using Geant4 and MCNPX to estimate dose rates and DNA damage

    NASA Astrophysics Data System (ADS)

    van den Akker, Mary Evelyn

    Radon is considered the second-leading cause of lung cancer after smoking. Epidemiological studies have been conducted in miner cohorts as well as general populations to estimate the risks associated with high and low dose exposures. There are problems with extrapolating risk estimates to low dose exposures, mainly that the dose-response curve at low doses is not well understood. Calculated dosimetric quantities give average energy depositions in an organ or a whole body, but morphological features of an individual can affect these values. As opposed to human phantom models, Computed Tomography (CT) scans provide unique, patient-specific geometries that are valuable in modeling the radiological effects of the short-lived radon progeny sources. Monte Carlo particle transport code Geant4 was used with the CT scan data to model radon inhalation in the main bronchial bifurcation. The equivalent dose rates are near the lower bounds of estimates found in the literature, depending on source volume. To complement the macroscopic study, simulations were run in a small tissue volume in Geant4-DNA toolkit. As an expansion of Geant4 meant to simulate direct physical interactions at the cellular level, the particle track structure of the radon progeny alphas can be analyzed to estimate the damage that can occur in sensitive cellular structures like the DNA molecule. These estimates of DNA double strand breaks are lower than those found in Geant4-DNA studies. Further refinements of the microscopic model are at the cutting edge of nanodosimetry research.

  16. Synthesis and degradation rates of collagens in vivo in whole skin of rats, studied with 1802 labelling.

    PubMed Central

    Molnar, J A; Alpert, N; Burke, J F; Young, V R

    1986-01-01

    Rats of synthesis and degradation in vivo of collagens in 0.5 M-acetic acid-soluble and -insoluble extracts from skins of three growing rats were determined by using a labelling procedure involving exposure of the animals to an atmosphere of 18O2 for 36 h. For comparison, rats also received injections of [2H]proline. Serial skin biopsies were taken at frequent intervals over 392 days. Enrichment of 18O and 2H in the hydroxyproline of the collagen fractions was determined by gas chromatography-mass spectrometry. Changes in size of the soluble and insoluble collagen pools were considered in the evaluation of isotope kinetic data. The insoluble collagen fraction showed no degradation. The efflux (mean +/- S.D., expressed as mumol of hydroxyproline) from the soluble collagen pool was estimated to be 59.9 +/- 1.9 per day from the 18O data, and 25.5 +/- 7.5 per day from the 2H results. The finding indicates significant reutilization of 2H-radiolabelled proline for hydroxyproline synthesis. From these isotope data and estimates of size of the collagen pools it was determined that 55% of the collagen disappearing from the soluble pool was due to maturation into insoluble collagens and 45% of the disappearance was a result of actual degradation of soluble collagen. These results confirm the utility of 18O2 as a non-reutilizable label for studies of collagen turnover in vivo. PMID:3814092

  17. Behavior of Bragg gratings, written in germanosilicate fibers, against [gamma]-ray exposure at low dose rate

    SciTech Connect

    Niay, P.; Bernage, P.; Douay, M.; Fertein, E.; Lahoreau, F. . Lab. de Dynamique Moleculaire et Photonique); Bayon, J.F.; Georges, T.; Monerie, M. ); Ferdinand, P.; Rougeault, S.; Cetier, P. )

    1994-11-01

    Bragg gratings have been written within four germanosilicate fibers either by a pulsed or by a continuous-wave exposure of each fiber to a coherent UV two-beam interference pattern. These gratings have been exposed under steady state conditions to [gamma]-ray doses as high as 10[sup 4] Grays. The dose rates ranged between 10 Gy/h and 1.3 [times] 10[sup 2] Gy/h. The transmission spectra of the fibers have been recorded during and after the [sup 60]Co irradiation, near the grating Bragg wavelengths. Whereas the induced loss reached 600 dB/km near 1.3 [mu]m, no significant change in the spectral characteristics of the gratings could be detected within the experimental accuracy, enabling their future use in a nuclear environment.

  18. Differences in prevalence rates of PTSD in various European countries explained by war exposure, other trauma and cultural value orientation

    PubMed Central

    2014-01-01

    Background Guided by previous explorations of historical and cultural influences on the occurrence of PTSD, the aim of the present study was to investigate the contributions of war victimisation (in particular, World War II) and other civil trauma on the prevalence of PTSD, as mediated by cultural value orientation. Secondary data analysis was performed for 12 European countries using data, including PTSD prevalence and number of war victims, crime victims, and natural disaster victims, from different sources. Ten single value orientations, as well as value aggregates for traditional and modern factors, were investigated. Results Whilst differences in PTSD prevalence were strongly associated with war victim rates, associations, albeit weaker, were also found between crime victims and PTSD. When cultural value orientations, such as stimulation and conformity as representatives of modern and traditional values, were included in the multivariate predictions of PTSD prevalence, an average of approximately 80% of PTSD variance could be explained by the model, independent of the type of trauma exposure. Conclusion The results suggest that the aftermath of war contributes to current PTSD prevalence, which may be explained by the high proportion of the older population who directly or indirectly experienced traumatic war experiences. Additional findings for other types of civil trauma point towards an interaction between value orientation and country-specific trauma rates. Particularly, being personally oriented towards stimulation appears to interact with differences in trauma prevalence. Thus, cultural value orientation might be viewed not only as an individual intrinsic process but also as a compensatory strategy after trauma exposure. PMID:24972489

  19. Barley mutants with low rates of endosperm starch synthesis have low grain dormancy and high susceptibility to preharvest sprouting.

    PubMed

    Howard, Thomas P; Fahy, Brendan; Craggs, Alice; Mumford, Rachel; Leigh, Fiona; Howell, Phil; Greenland, Andy; Smith, Alison M

    2012-04-01

    • Studies of embryo dormancy in relation to preharvest sprouting (PHS) in cereals have focused on ABA and other hormones. The relationship between these phenomena and the rate of grain filling has not been investigated. • A collection of barley mutants impaired in starch synthesis was assessed for preharvest sprouting in the field. In subsequent glasshouse experiments, developing grains were assayed for germination index, sugars, abscisic acid (ABA) and the effects of temperature and exogenous ABA on germination. • Mutant lines displayed greater preharvest sprouting in the field than parental lines. In the glasshouse, nondeep physiological dormancy was reduced in developing grains of five lines with mutations affecting proteins involved in endosperm starch synthesis. Inhibition of germination by exogenous ABA and elevated temperature was decreased in developing mutant grains. Sugar concentrations were high but embryo and endosperm ABA contents were unaltered. • We reveal a direct connection between grain filling and the extent of grain dormancy. Impaired endosperm starch synthesis directly influences the acquisition of embryo dormancy, perhaps because endosperm sugar concentrations modulate the ABA responsiveness of the embryo. Thus environmental or genetic factors that reduce grain filling are likely to reduce dormancy and enhance susceptibility to PHS. PMID:22300545

  20. Characterization of emissions from portable household combustion devices: particle size distributions, emission rates and factors, and potential exposures

    NASA Astrophysics Data System (ADS)

    Fan, Cheng-Wei; Zhang, Junfeng (Jim)

    A series of source tests were conducted to characterize emissions of particulate matter (PM), carbon monoxide (CO), carbon dioxide (CO 2), methane (CH 4), and total hydrocarbon (THC ) from five types of portable combustion devices. Tested combustion devices included a kerosene lamp, an oil lamp, a kerosene space heater, a portable gas range, and four unscented candles. All tests were conducted either in a well-mixed chamber or a well-mixed room, which enables us to determine emission rates and emission factors using a single-compartment mass balance model. Particle mass concentrations and number concentrations were measured using a nephelometric particle monitor and an eight-channel optical particle counter, respectively. Real-time CO concentrations were measured with an electrochemical sensor CO monitor. CO 2, CH 4, and THC were measured using a GC-FID technique. The results indicate that all particles emitted during steady burning in each of the tested devices were smaller than 1.0 μm in diameter with the vast majority in the range between 0.1 and 0.3 μm. The PM mass emission rates and emission factors for the tested devices ranged from 5.6±0.1 to 142.3±40.8 mg h -1 and from 0.35±0.06 to 9.04±4.0 mg g -1, respectively. The CO emission rates and emission factors ranged from 4.7±3.0 to 226.7±100 mg h -1 and from 0.25±0.12 to 1.56±0.7 mg g -1, respectively. The CO 2 emission rates and emission factors ranged from 5500±700 to 210,000±90,000 mg h -1 and from 387±45 to 1689±640 mg g -1, respectively. The contributions of CH 4 and THC to emission inventories are expected to be insignificant due both to the small emission factors and to the relatively small quantity of fuel consumed by these portable devices. An exposure scenario analysis indicates that every-day use of the kerosene lamp in a village house can generate fine PM exposures easily exceeding the US promulgated NAAQS for PM 2.5.

  1. Tumor necrosis factor-α suppresses the protein fractional synthesis rate of the small intestine stimulated by glutamine in rats

    PubMed Central

    ZHOU, JIHONG; FAN, SHENGXIAN; CAO, YACHENG; ZHU, MINGFANG; HAN, YONG; CAO, XUEYING; LI, YOUSHENG

    2015-01-01

    The objective of this study was to examine whether and how TNF-α affects glutamine-enhanced protein synthesis and the expression of the amino acid transporter ASCT2 in the small intestine at the mRNA and protein levels. A total of 30 male Sprague-Dawley rats were randomly assigned into three groups, namely the total parenteral nutrition (TPN; control), glutamine-treated (Gln), and glutamine- and tumor necrosis factor-α (TNF-α)-treated (TNF-α) groups. At 30 min prior to examination, all rats were mainlined with [L-15N]leucine. The concentration of TNF-α in plasma and of glutamine in plasma and the small intestine was measured. The fractional synthesis rate (FSR) of protein and the mRNA and protein expression levels of ASCT2 in the small intestine were assessed. The level of TNF-α was highest in the TNF-α group and the glutamine concentration was elevated to a greater extent in the TNF-α group than in the other two groups. However, the FSR of protein in the small intestine was significantly higher in the Gln group compared with that in the TNF-α group. The mRNA and protein expression levels of ASCT2 in the experimental groups were significantly higher that those in the control group, but did not differ significantly between the Gln and TNF-α groups. These results indicate that TNF-α may attenuate glutamine-stimulated protein synthesis in the small intestine in the early stage of sepsis in rats. The mechanism may be that TNF-α inhibits the function of the glutamine transporter in the uptake the glutamine into target cells for protein synthesis. This inhibition may occur at or following protein translation. PMID:25574232

  2. Estimating the effects of 17α-ethinylestradiol on stochastic population growth rate of fathead minnows: a population synthesis of empirically derived vital rates.

    PubMed

    Schwindt, Adam R; Winkelman, Dana L

    2016-09-01

    Urban freshwater streams in arid climates are wastewater effluent dominated ecosystems particularly impacted by bioactive chemicals including steroid estrogens that disrupt vertebrate reproduction. However, more understanding of the population and ecological consequences of exposure to wastewater effluent is needed. We used empirically derived vital rate estimates from a mesocosm study to develop a stochastic stage-structured population model and evaluated the effect of 17α-ethinylestradiol (EE2), the estrogen in human contraceptive pills, on fathead minnow Pimephales promelas stochastic population growth rate. Tested EE2 concentrations ranged from 3.2 to 10.9 ng L(-1) and produced stochastic population growth rates (λ S ) below 1 at the lowest concentration, indicating potential for population decline. Declines in λ S compared to controls were evident in treatments that were lethal to adult males despite statistically insignificant effects on egg production and juvenile recruitment. In fact, results indicated that λ S was most sensitive to the survival of juveniles and female egg production. More broadly, our results document that population model results may differ even when empirically derived estimates of vital rates are similar among experimental treatments, and demonstrate how population models integrate and project the effects of stressors throughout the life cycle. Thus, stochastic population models can more effectively evaluate the ecological consequences of experimentally derived vital rates. PMID:27372448

  3. Urea synthesis in the African lungfish Protopterus dolloi--hepatic carbamoyl phosphate synthetase III and glutamine synthetase are upregulated by 6 days of aerial exposure.

    PubMed

    Chew, Shit F; Ong, Tan F; Ho, Lilian; Tam, Wai L; Loong, Ai M; Hiong, Kum C; Wong, Wai P; Ip, Yuen K

    2003-10-01

    Like the marine ray Taeniura lymma, the African lungfish Protopterus dolloi possesses carbamoyl phosphate III (CPS III) in the liver and not carbamoyl phosphate I (CPS I), as in the mouse Mus musculus or as in other African lungfish reported elsewhere. However, similar to other African lungfish and tetrapods, hepatic arginase of P. dolloi is present mainly in the cytosol. Glutamine synthetase activity is present in both the mitochondrial and cytosolic fractions of the liver of P. dolloi. Therefore, we conclude that P. dolloi is a more primitive extant lungfish, which is intermediate between aquatic fish and terrestrial tetrapods, and represents a link in the fish-tetrapod continuum. During 6 days of aerial exposure, the ammonia excretion rate in P. dolloi decreased significantly to 8-16% of the submerged control. However, there were no significant increases in ammonia contents in the muscle, liver or plasma of specimens exposed to air for 6 days. These results suggest that (1). endogenous ammonia production was drastically reduced and (2). endogenous ammonia was detoxified effectively into urea. Indeed, there were significant decreases in glutamate, glutamine and lysine levels in the livers of fish exposed to air, which led to a decrease in the total free amino acid content. This indirectly confirms that the specimen had reduced its rates of proteolysis and/or amino acid catabolism to suppress endogenous ammonia production. Simultaneously, there were significant increases in urea levels in the muscle (8-fold), liver (10.5-fold) and plasma (12.6-fold) of specimens exposed to air for 6 days. Furthermore, there was an increase in the hepatic ornithine-urea cycle (OUC) capacity, with significant increases in the activities of CPS III (3.8-fold), argininosuccinate synthetase + lyase (1.8-fold) and, more importantly, glutamine synthetase (2.2-fold). This is the first report on the upregulation of OUC capacity and urea synthesis rate in an African lungfish exposed to air

  4. SCINTILLATION EXPOSURE RATE DETECTOR

    DOEpatents

    Spears, W.G.

    1960-11-01

    A radiation detector for gamma and x rays is described. The detector comprises a scintillation crystal disposed between a tantalum shield and the input of a photomultiplier tube, the crystal and the shield cooperating so that their combined response to a given quantity of radiation at various energy levels is substantially constant.

  5. EFFECTS OF SUBCHRONIC EXPOSURE TO CONCENTRATED AMBIENT PARTICULATES ON ELECTROCARDIOGRAM AND HEART RATE VARIABILITY IN SPONTANEOUSLY HYPERTENSIVE RATS

    EPA Science Inventory


    Epidemiological studies have linked air pollution exposure to adverse respiratory health effects, especially in individuals with inflammatory airways disease. Symptomatic asthmatics appear to be at greatest risk. We previously demonstrated that exposure of rats to particulate...

  6. A single exposure to acrolein causes arrhythmogenesis, cardiac electrical dysfunction and decreased heart rate variability in hypertensive rats

    EPA Science Inventory

    Epidemiological studies demonstrate an association between cardiovascular morbidity, arrhythmias, and exposure to air toxicants such as acrolein. We hypothesized that a single exposure to acrolein would increase arrhythmias and cause changes in the electrocardiogram (ECG) of hype...

  7. Methane hydrate synthesis from ice: Influence of pressurization and ethanol on optimizing formation rates and hydrate yield

    USGS Publications Warehouse

    Chen, Po-Chun.; Huang, Wuu-Liang; Stern, Laura A.

    2010-01-01

    Polycrystalline methane gas hydrate (MGH) was synthesized using an ice-seeding method to investigate the influence of pressurization and ethanol on the hydrate formation rate and gas yield of the resulting samples. When the reactor is pressurized with CH4 gas without external heating, methane hydrate can be formed from ice grains with yields up to 25% under otherwise static conditions. The rapid temperature rise caused by pressurization partially melts the granular ice, which reacts with methane to form hydrate rinds around the ice grains. The heat generated by the exothermic reaction of methane hydrate formation buffers the sample temperature near the melting point of ice for enough time to allow for continuous hydrate growth at high rates. Surprisingly, faster rates and higher yields of methane hydrate were found in runs with lower initial temperatures, slower rates of pressurization, higher porosity of the granular ice samples, or mixtures with sediments. The addition of ethanol also dramatically enhanced the formation of polycrystalline MGH. This study demonstrates that polycrystalline MGH with varied physical properties suitable for different laboratory tests can be manufactured by controlling synthesis procedures or parameters. Subsequent dissociation experiments using a gas collection apparatus and flowmeter confirmed high methane saturation (CH 4·2O, with n = 5.82 ± 0.03) in the MGH. Dissociation rates of the various samples synthesized at diverse conditions may be fitted to different rate laws, including zero and first order.

  8. Mortality and F1 progeny of the lesser grain borer, Rhyzopertha dominica (F), on wheat treated with diatomaceous earth: effects of rate, exposure period and relative humidity.

    PubMed

    Ferizli, Ahmet G; Beris, Gulay

    2005-11-01

    A series of experiments at 25 (+/-1) degrees C were conducted in which different application rates of diatomaceous earth (DE) formulation Protect-It at two levels of relative humidity, 40 and 55%, and at three exposure periods were evaluated for control of Rhyzopertha dominica (F). Test insects were placed in vials containing 40 g of soft winter wheat mixed with 0.25, 0.50, 1.00, 1.50 and 2.00 g DE kg(-1). At all rates except 0.25 g kg(-1), mortality was significantly different from that in the control at the relevant exposure period. After each exposure interval, dead and live insects were counted and removed, and the vial containing wheat was then returned to the appropriate humidity chamber for 8 weeks until F(1) adults emerged. F(1) progeny production was significantly different from the control group at all rates. Mortalities for 1, 2 and 3 weeks exposure were found to be 47 (+/-5)%. Despite the fact that mortality increased with increasing rate, total mortality was not achieved even at the highest rate of DE. F(1) progeny production decreased with increasing rate for both RH conditions, and containment of population for both RH conditions was achieved at 1.00 g DE kg(-1). For each exposure period, F(1) progeny production of R dominica decreased with increasing rate of DE, and population suppression was achieved at 1.00 g DE kg(-1) for all exposure intervals. In summary, Protect-It resulted in reduced F(1) adult progeny and containment of population was achieved at 1.00 g DE kg(-1) at which rate mortality was 77%.

  9. Synthesis and electrochemical characterization of stoichiometric Cu2S as cathode material with high rate capability for rechargeable lithium batteries

    NASA Astrophysics Data System (ADS)

    Kalimuldina, Gulnur; Taniguchi, Izumi

    2016-11-01

    Synthesis of stoichiometric copper sulfide (Cu2S) was studied by spray pyrolysis (SP) with heat treatment for different Cu/S molar ratios in the starting solution and different synthesis and annealing temperatures. The sample prepared via SP at 400 °C and then annealed at 460 °C for 2 h showed the stoichiometric Cu/S ratio, which was verified by inductively coupled plasma-optical emission spectroscopy. The X-ray diffraction (XRD) peaks of the sample were indexed to the monoclinic structure with space group P21/c. The electrochemical performance of the stoichiometric Cu2S electrode was investigated by a cycle test and differential capacity analysis. The Cu2S electrode coated on an Al foil exhibited a first discharge capacity of 335 mAh g-1 at a charge-discharge rate of 0.1 C, which corresponds to 99.4% of its theoretical capacity. However it showed poor reversibility owing to the corrosion of Al foil by Cu. In contrast, the Cu2S electrode coated on Cu foil demonstrated stable cyclability at high charge-discharge rates of up to 30 C. Exsitu XRD analysis showed that a phase transformation from the monoclinic Cu2S structure with the space group P21/c to the tetragonal Cu1.96S structure with the space group P43212 gradually progressed during the initial five cycles.

  10. Association between indoor air pollutant exposure and blood pressure and heart rate in subjects according to body mass index.

    PubMed

    Jung, Chien-Cheng; Su, Huey-Jen; Liang, Hsiu-Hao

    2016-01-01

    This study investigates the effects of high body mass index (BMI) of subjects on individual who exhibited high cardiovascular disease indexes with blood pressure (BP) and heart rate (HR) when exposed to high levels of indoor air pollutants. We collected 115 office workers, and measured their systolic blood pressure (SBP), diastolic blood pressure (DBP) and HR at the end of the workday. The subjects were divided into three groups according to BMI: 18-24 (normal weight), 24-27 (overweight) and >27 (obese). This study also measured the levels of carbon dioxide (CO2), total volatile organic compounds (TVOC), particulate matter with an aerodynamic diameter less than 2.5μm (PM2.5), as well as the bacteria and fungi in the subjects' work-places. The pollutant effects were divided by median. Two-way analysis of variance (ANOVA) was used to analyze the health effects of indoor air pollution exposure according to BMI. Our study showed that higher levels of SBP, DBP and HR occurred in subjects who were overweight or obese as compared to those with normal weight. Moreover, there was higher level of SBP in subjects who were overweight or obese when they were exposed to higher levels of TVOC and fungi (p<0.05). We also found higher value for DBP and HR with increasing BMI to be associated with exposure to higher TVOC levels. This study suggests that individuals with higher BMI have higher cardiovascular disease risk when they are exposed to poor indoor air quality (IAQ), and specifically in terms of TVOC.

  11. Association of Chromosome Translocation Rate with Low Dose Occupational Radiation Exposures in U.S. Radiologic Technologists

    PubMed Central

    Little, Mark P.; Kwon, Deukwoo; Doi, Kazataka; Simon, Steven L.; Preston, Dale L.; Doody, Michele M.; Lee, Terrence; Miller, Jeremy S.; Kampa, Diane M.; Bhatti, Parveen; Tucker, James D.; Linet, Martha S.; Sigurdson, Alice J.

    2016-01-01

    Chromosome translocations are a well-recognized biological marker of radiation exposure and cancer risk. However, there is uncertainty about the lowest dose at which excess translocations can be detected, and whether there is temporal decay of induced translocations in radiation-exposed populations. Dosimetric uncertainties can substantially alter the shape of dose-response relationships; although regression-calibration methods have been used in some datasets, these have not been applied in radio-occupational studies, where there are also complex patterns of shared and unshared errors that these methods do not account for. In this article we evaluated the relationship between estimated occupational ionizing radiation doses and chromosome translocation rates using fluorescent in situ hybridization in 238 U.S. radiologic technologists selected from a large cohort. Estimated cumulative red bone marrow doses (mean 29.3 mGy, range 0–135.7 mGy) were based on available badge–dose measurement data and on questionnaire-reported work history factors. Dosimetric assessment uncertainties were evaluated using regression calibration, Bayesian and Monte Carlo maximum likelihood methods, taking account of shared and unshared error and adjusted for overdispersion. There was a significant dose response for estimated occupational radiation exposure, adjusted for questionnaire-based personal diagnostic radiation, age, sex and study group (5.7 translocations per 100 whole genome cell equivalents per Gy, 95% CI 0.2, 11.3, P = 0.0440). A significant increasing trend with dose continued to be observed for individuals with estimated doses <100 mGy. For combined estimated occupational and personal-diagnostic-medical radiation exposures, there was a borderline-significant modifying effect of age (P 0.0704), but little evidence (P > 0.5) of temporal decay of induced translocations. The three methods of analysis to adjust for dose uncertainty gave similar results. In summary, chromosome

  12. Relative Importance of Climate Variables to Population Vital Rates: A Quantitative Synthesis for the Lesser Prairie-Chicken

    PubMed Central

    Fuhlendorf, Samuel D.

    2016-01-01

    Climate change is expected to affect temperature and precipitation means and extremes, which can affect population vital rates. With the added complexity of accounting for both means and extremes, it is important to understand whether one aspect is sufficient to predict a particular vital rate or if both are necessary. To compare the predictive ability of climate means and extremes with geographic, individual, and habitat variables, we performed a quantitative synthesis on the vital rates of lesser prairie-chickens (Tympanuchus pallidictinus) across their geographic range. We used an information theoretic approach to rank models predicting vital rates. We were able to rank climate models for three vital rates: clutch size, nest success, and subadult/adult seasonal survival. Of these three vital rates, a climate model was never the best predictor even when accounting for potentially different relationships between climate variables and vital rates between different ecoregions. Clutch size and nest success were both influenced by nesting attempt with larger clutches and greater success for first nesting attempts than second nesting attempts. Clutch size also increased with latitude for first nesting attempts but decreased with latitude for second nesting attempts. This resulted in similar clutch sizes for first and second nest attempts at southern latitudes but larger clutches for first nest attempts than second nest attempts at northern latitudes. Survival was greater for subadults than adults, but there were few estimates of subadult survival for comparison. Our results show that individual characteristics and geographic variables are better for predicting vital rates than climate variables. This may due to low samples sizes, which restricted our statistical power, or lack of precision in climate estimates relative to microclimates actually experienced by individuals. Alternatively, relationships between climate variables and vital rates may be constrained by time

  13. Acetyl-coenzyme A synthesis from methyltetrahydrofolate, CO, and coenzyme A by enzymes purified from Clostridium thermoaceticum: attainment of in vivo rates and identification of rate-limiting steps.

    PubMed Central

    Roberts, J R; Lu, W P; Ragsdale, S W

    1992-01-01

    Many anaerobic bacteria fix CO2 via the acetyl-coenzyme A (CoA) (Wood) pathway. Carbon monoxide dehydrogenase (CODH), a corrinoid/iron-sulfur protein (C/Fe-SP), methyltransferase (MeTr), and an electron transfer protein such as ferredoxin II play pivotal roles in the conversion of methyltetrahydrofolate (CH3-H4folate), CO, and CoA to acetyl-CoA. In the study reported here, our goals were (i) to optimize the method for determining the activity of the synthesis of acetyl-CoA, (ii) to evaluate how closely the rate of synthesis of acetyl-CoA by purified enzymes approaches the rate at which whole cells synthesize acetate, and (iii) to determine which steps limit the rate of acetyl-CoA synthesis. In this study, CODH, MeTr, C/Fe-SP, and ferredoxin were purified from Clostridium thermoaceticum to apparent homogeneity. We optimized conditions for studying the synthesis of acetyl-CoA and found that when the reaction is dependent upon MeTr, the rate is 5.3 mumol min-1 mg-1 of MeTr. This rate is approximately 10-fold higher than that reported previously and is as fast as that predicted on the basis of the rate of in vivo acetate synthesis. When the reaction is dependent upon CODH, the rate of acetyl-CoA synthesis is approximately 0.82 mumol min-1 mg-1, approximately 10-fold higher than that observed previously; however, it is still lower than the rate of in vivo acetate synthesis. It appears that at least two steps in the overall synthesis of acetyl-CoA from CH3-H4folate, CO, and CoA can be partially rate limiting. At optimal conditions of low pH (approximately 5.8) and low ionic strength, the rate-limiting step involves methylation of CODH by the methylated C/Fe-SP. At higher pH values and/or higher ionic strength, transfer of the methyl group of CH3-H4folate to the C/Fe-SP becomes rate limiting. Images PMID:1624454

  14. A simple approach to evaluate the kinetic rate constant for ATP synthesis in resting human skeletal muscle at 7 T.

    PubMed

    Ren, Jimin; Sherry, A Dean; Malloy, Craig R

    2016-09-01

    Inversion transfer (IT) is a well-established technique with multiple attractive features for analysis of kinetics. However, its application in measurement of ATP synthesis rate in vivo has lagged behind the more common saturation transfer (ST) techniques. One well-recognized issue with IT is the complexity of data analysis in comparison with much simpler analysis by ST. This complexity arises, in part, because the γ-ATP spin is involved in multiple chemical reactions and magnetization exchanges, whereas Pi is involved in a single reaction, Pi → γ-ATP. By considering the reactions involving γ-ATP only as a lumped constant, the rate constant for the reaction of physiological interest, kPi→γATP , can be determined. Here, we present a new IT data analysis method to evaluate kPi→γATP using data collected from resting human skeletal muscle at 7 T. The method is based on the basic Bloch-McConnell equation, which relates kPi→γATP to m˙Pi, the rate of Pi magnetization change. The kPi→γATP value is accessed from m˙Pi data by more familiar linear correlation approaches. For a group of human subjects (n = 15), the kPi→γATP value derived for resting calf muscle was 0.066 ± 0.017 s(-1) , in agreement with literature-reported values. In this study we also explored possible time-saving strategies to speed up data acquisition for kPi→γATP evaluation using simulations. The analysis indicates that it is feasible to carry out a (31) P IT experiment in about 10 min or less at 7 T with reasonable outcome in kPi→γATP variance for measurement of ATP synthesis in resting human skeletal muscle. We believe that this new IT data analysis approach will facilitate the wide acceptance of IT to evaluate ATP synthesis rate in vivo. Copyright © 2015 John Wiley & Sons, Ltd.

  15. Rates of opioid misuse, abuse, and addiction in chronic pain: a systematic review and data synthesis.

    PubMed

    Vowles, Kevin E; McEntee, Mindy L; Julnes, Peter Siyahhan; Frohe, Tessa; Ney, John P; van der Goes, David N

    2015-04-01

    Opioid use in chronic pain treatment is complex, as patients may derive both benefit and harm. Identification of individuals currently using opioids in a problematic way is important given the substantial recent increases in prescription rates and consequent increases in morbidity and mortality. The present review provides updated and expanded information regarding rates of problematic opioid use in chronic pain. Because previous reviews have indicated substantial variability in this literature, several steps were taken to enhance precision and utility. First, problematic use was coded using explicitly defined terms, referring to different patterns of use (ie, misuse, abuse, and addiction). Second, average prevalence rates were calculated and weighted by sample size and study quality. Third, the influence of differences in study methodology was examined. In total, data from 38 studies were included. Rates of problematic use were quite broad, ranging from <1% to 81% across studies. Across most calculations, rates of misuse averaged between 21% and 29% (range, 95% confidence interval [CI]: 13%-38%). Rates of addiction averaged between 8% and 12% (range, 95% CI: 3%-17%). Abuse was reported in only a single study. Only 1 difference emerged when study methods were examined, where rates of addiction were lower in studies that identified prevalence assessment as a primary, rather than secondary, objective. Although significant variability remains in this literature, this review provides guidance regarding possible average rates of opioid misuse and addiction and also highlights areas in need of further clarification.

  16. Rate and topography of peptidoglycan synthesis during cell division in Escherichia coli: Concept of a leading edge

    SciTech Connect

    Wientjes, F.B.; Nanninga, N. )

    1989-06-01

    The rate at which the peptidoglycan of Escherichia coli is synthesized during the division cycle was studied with two methods. One method involved synchronization of E. coli MC4100 lysA cultures by centrifugal elutriation and subsequent pulse-labeling of the synchronously growing cultures with (meso-{sup 3}H)diaminopimelic acid (({sup 3}H)Dap). The second method was autoradiography of cells pulse-labeled with ({sup 3}H)Dap. It was found that the peptidoglycan is synthesized at a more or less exponentially increasing rate during the division cycle with a slight acceleration in this rate as the cells start to constrict. Apparently, polar cap formation requires synthesis of extra surface components, presumably to accommodate for a change in the surface-to-volume ratio. Furthermore, it was found that the pool size of Dap was constant during the division cycle. Close analysis of the topography of ({sup 3}H)Dap incorporation at the constriction site revealed that constriction proceeded by synthesis of peptidoglycan at the leading edge of the invaginating cell envelope. During constriction, no reallocation of incorporation occurred, i.e., the incorporation at the leading edge remained high throughout the process of constriction. Impairment of penicillin-binding protein 3 by mutation or by the specific {beta}-lactam antibiotic furazlocillin did not affect ({sup 3}H)Dap incorporation during initiation of constriction. However, the incorporation at the constriction site was inhibited in later stages of the constriction process. It is concluded that during division at least two peptidoglycan-synthesizing systems are operating sequentially.

  17. 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

  18. Effects of long-term exposure to ammonium sulfate particles on growth and gas exchange rates of Fagus crenata, Castanopsis sieboldii, Larix kaempferi and Cryptomeria japonica seedlings

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Masahiro; Otani, Yoko; Li, Peiran; Nagao, Hiroshi; Lenggoro, I. Wuled; Ishida, Atsushi; Yazaki, Kenichi; Noguchi, Kyotaro; Nakaba, Satoshi; Yamane, Kenichi; Kuroda, Katsushi; Sano, Yuzou; Funada, Ryo; Izuta, Takeshi

    2014-11-01

    To clarify the effects of long-term exposure to ammonium sulfate (AS) particles on growth and physiological functions of forest tree species, seedlings of Fagus crenata, Castanopsis sieboldii, Larix kaempferi and Cryptomeria japonica were exposed to submicron-size AS particles during two growing seasons from 3 June 2011 to 8 October 2012. The mean sulfate concentration in PM2.5 increased during the exposure inside the chamber in 2011 and 2012 by 2.73 and 4.32 μg SO42- m-3, respectively. No significant effects of exposure to AS particles were detected on the whole-plant dry mass of the seedlings. These results indicate that the exposure to submicrometer AS particles at the ambient level for two growing seasons did not significantly affect the growth of the seedlings. No significant effects of exposure to AS particles were found on the net photosynthetic rate in the leaves or needles of F. crenata, C. sieboldii and L. kaempferi seedlings. Also, in the previous-year needles of C. japonica seedlings, exposure to AS particles significantly reduced the net photosynthetic rate, which may be caused by the reduction in the concentration of ribulose-1, 5-bisphosphate carboxylase/oxygenase (Rubisco). On the contrary, in current-year needles of C. japonica seedlings, net photosynthetic rate significantly increased with exposure to AS particles, which may be the result of increases in stomatal conductance and concentrations of Rubisco and chlorophyll. Furthermore, exposure to AS particles correlated with an increase in concentrations of NH4+, free amino acid and total soluble protein, suggesting that AS particles may be deliquesced, absorbed into the leaves and metabolized into amino acid and protein. These results suggest that net photosynthesis in the needles of C. japonica is relatively sensitive to submicron-size AS particles as compared with the other three tree species.

  19. Rate and style of ice stream retreat constrained by new surface-exposure ages: The Minch, NW Scotland

    NASA Astrophysics Data System (ADS)

    Bradwell, Tom; Small, David; Fabel, Derek; Dove, Dayton; Cofaigh, Colm O.; Clark, Chris; Consortium, Britice-Chrono

    2016-04-01

    Chronologically constrained studies of former ice-sheet extents and dynamics are important for understanding past cryospheric responses and modelling future ice-sheet and sea-level change. As part of the BRITICE-CHRONO project, we present new geomorphological and chronological data from a marine-terminating ice stream system in NW Europe that operated during the Late Weichselian Glaciation. A suite of 51 cosmogenic-nuclide exposure ages from ice sheet moraines and glacially transported boulders constrain the maximum extent of the ice sheet on the continental shelf (~28 ka BP) and its subsequent retreat, between ~27 and 16 ka BP, into a large marine embayment (ca. 7000 km2; the Minch, NW Scotland). Recently acquired swath bathymetry and acoustic sub-bottom profiler data reveal several large transverse grounding-zone wedges up to 40 m thick and 5 km wide with diagnostic acoustic-facies architecture. These seabed sediment wedges mark former quasi-stable positions of grounded marine-terminating ice-stream fronts; their size and thickness suggest long-lived stillstands of the order of centuries. Statistically significant clusters of exposure ages from glacial deposits on islands and intervening headlands shed important new light on the age of these marine grounding-zone wedges and, by inference, the rate and timing of Minch palaeo-ice stream retreat. We find strong evidence for episodic ice stream retreat on the continental shelf between ~28-24 ka BP, in the outer Minch between ~24-22 ka BP, and in the central Minch between 22-18.5 ka BP. In contrast, final ice stream deglaciation (<18 ka) across the deepest parts of the inner Minch embayment, was probably rapid and uninterrupted - with the ice sheet margin at or close to the present-day coastline in NW Scotland by 16.1 ka BP. It is hoped that these results will form the empirical basis for future ice-sheet modelling of this dynamically sensitive sector of the British-Irish Ice Sheet.

  20. Trichrome Mallory's stain may indicate differential rates of RNA synthesis in eutopic and ectopic endometrium.

    PubMed

    Wołuń-Cholewa, Maria; Szymanowski, Krzysztof; Andrusiewicz, Mirosław; Szczerba, Anna; Warchoł, Jerzy B

    2010-01-01

    Mallory's triple staining is a histochemical technique used mainly for analysing connective tissues and glands and other tissues. We have described the differences in the nuclear staining between eutopic and ectopic endometrium as well as endometrial hyperplasia and adenocarcinoma using the Mallory's method. The ultrastructural differences between eutopic and ectopic endometrium have been detected. In normal and hyperplastic endometrium the presence of stromal cell nuclei with an increased affinity to aniline blue has been observed. The affinity has disappeared after digestion of tissues with RNase. In cases of endometriosis, independently of cell types, the nuclei have shown affinity to orange G. Similar effects in adenocarcinoma have been noted. The ultrastructural studies have shown that in normal endometrium the stroma contained cells with euchromatic and low electron density cell nuclei. In endometriosis heterochromatic cell nuclei present both in the stroma and within glands have been detected. The results indicate that the Mallory's technique may be a useful tool for recognizing the differences between eutopic and ectopic endometrium. The affinity for aniline blue in normal and hyperplastic endometrium occurs most likely due to increased RNA synthesis. Based on Mallory's staining a similarity between hyperplasia and unchanged endometrium in contrast to similar results of the staining obtained in cases of adenocarcinoma and endometriosis may be suggested.

  1. Effect of endotoxin on plasma albumin and fibrinogen synthesis rates in rabbits as measured by the [14C]carbonate method

    PubMed Central

    Koj, A.; McFarlane, A. S.

    1968-01-01

    1. Rates of synthesis of plasma albumin and fibrinogen were measured by the [14C]carbonate method in normal rabbits and in animals that received a single intravenous injection of Shigella endotoxin 14–48hr. earlier. 2. The accuracy of the method was improved by introducing refinements into procedures for measuring 14C radioactivities associated with both urea and proteins that are lost from the plasma during the synthesis interval. 3. The synthesis interval (time between injecting carbonate and measuring specific radioactivities of protein guanidine carbon in plasma) can be shortened with advantage to 3–4hr. 4. Injection of endotoxin markedly decreased the fractional rate of loss in the first few hours of injected radioiodine-labelled fibrinogen and to a smaller extent of similarly labelled albumin from the plasma. The absolute rate of synthesis of fibrinogen was increased in endotoxin-treated rabbits by more than 400% compared with normal animals, and the rate of synthesis of albumin was increased by about 60%. PMID:4872487

  2. Metabolism of Nonessential N15-Labeled Amino Acids and the Measurement of Human Whole-Body Protein Synthesis Rates

    NASA Technical Reports Server (NTRS)

    Stein, T. P.; Settle, R. G.; Albina, J. A.; Dempsey, D. T.; Melnick, G.

    1991-01-01

    Eight N-15 labeled nonessential amino acids plus (15)NH4Cl were administered over a 10 h period to four healthy adult males using a primed-constant dosage regimen. The amount of N-15 excreted in the urine and the urinary ammonia, hippuric acid, and plasma alanine N-15 enrichments were measured. There was a high degree of consistency across subjects in the ordering of the nine compounds based on the fraction of N-15 excreted (Kendall coefficient of concordance W = 0.83, P is less than 0.01). Protein synthesis rates were calculated from the urinary ammonia plateau enrichment and the cumulative excretion of N-15. Glycine was one of the few amino acids that gave similar values by both methods.

  3. The relationship between the growth rate and the lifetime in carbon nanotube synthesis

    NASA Astrophysics Data System (ADS)

    Chen, Guohai; Davis, Robert C.; Kimura, Hiroe; Sakurai, Shunsuke; Yumura, Motoo; Futaba, Don N.; Hata, Kenji

    2015-05-01

    We report an inverse relationship between the carbon nanotube (CNT) growth rate and the catalyst lifetime by investigating the dependence of growth kinetics for ~330 CNT forests on the carbon feedstock, carbon concentration, and growth temperature. We found that the increased growth temperature led to increased CNT growth rate and shortened catalyst lifetime for all carbon feedstocks, following an inverse relationship of a fairly constant maximum height. For the increased carbon concentration, the carbon feedstocks fell into two groups where ethylene/butane showed an increased/decreased growth rate and a decreased/increased lifetime indicating different rate-limiting growth processes. In addition, this inverse relationship held true for different types of CNTs synthesized by various chemical vapor deposition techniques and continuously spanned a 1000-times range in both the growth rate and catalyst lifetime, indicating the generality and fundamental nature of this behavior originating from the growth mechanism of CNTs itself. These results suggest that it would be fundamentally difficult to achieve a fast growth with a long lifetime.

  4. The relationship between the growth rate and the lifetime in carbon nanotube synthesis.

    PubMed

    Chen, Guohai; Davis, Robert C; Kimura, Hiroe; Sakurai, Shunsuke; Yumura, Motoo; Futaba, Don N; Hata, Kenji

    2015-05-21

    We report an inverse relationship between the carbon nanotube (CNT) growth rate and the catalyst lifetime by investigating the dependence of growth kinetics for ∼330 CNT forests on the carbon feedstock, carbon concentration, and growth temperature. We found that the increased growth temperature led to increased CNT growth rate and shortened catalyst lifetime for all carbon feedstocks, following an inverse relationship of a fairly constant maximum height. For the increased carbon concentration, the carbon feedstocks fell into two groups where ethylene/butane showed an increased/decreased growth rate and a decreased/increased lifetime indicating different rate-limiting growth processes. In addition, this inverse relationship held true for different types of CNTs synthesized by various chemical vapor deposition techniques and continuously spanned a 1000-times range in both the growth rate and catalyst lifetime, indicating the generality and fundamental nature of this behavior originating from the growth mechanism of CNTs itself. These results suggest that it would be fundamentally difficult to achieve a fast growth with a long lifetime. PMID:25913386

  5. Contribution of exposure, risk of crash and fatality to explain age- and sex-related differences in traffic-related cyclist mortality rates.

    PubMed

    Martínez-Ruiz, Virginia; Jiménez-Mejías, Eladio; Amezcua-Prieto, Carmen; Olmedo-Requena, Rocío; Luna-del-Castillo, Juan de Dios; Lardelli-Claret, Pablo

    2015-03-01

    This study was designed to quantify the percent contribution of exposure, risk of collision and fatality rate to the association of age and sex with the mortality rates among cyclists in Spain, and to track the changes in these contributions with time. Data were analyzed for 50,042 cyclists involved in road crashes in Spain from 1993 to 2011, and also for a subset of 13,119 non-infractor cyclists involved in collisions with a vehicle whose driver committed an infraction (used as a proxy sample of all cyclists on the road). We used decomposition and quasi-induced exposure methods to obtain the percent contributions of these three components to the mortality rate ratios for each age and sex group compared to males aged 25-34 years. Death rates increased with age, and the main component of this increase was fatality (around 70%). Among younger cyclists, however, the main component of increased death rates was risk of a collision. Males had higher death rates than females in every age group: this rate increased from 6.4 in the 5-14 year old group to 18.8 in the 65-79 year old group. Exposure, the main component of this increase, ranged between 70% and 90% in all age categories, although the fatality component also contributed to this increase. The contributions of exposure, risk of crash and fatality to cyclist death rates were strongly associated with age and sex. Young male cyclists were a high-risk group because all three components tended to increase their mortality rate. PMID:25658669

  6. High rate of schistosomiasis in travelers after a brief exposure to the high-altitude Nyinambuga crater lake, Uganda.

    PubMed

    Lachish, Tamar; Tandlich, Moshik; Grossman, Tamar; Schwartz, Eli

    2013-11-01

    Travel-related schistosomiasis is usually associated with prolonged freshwater exposure. Until recently, Uganda's crater lakes were considered schistosomiasis free due to their high-altitude location. We describe an outbreak of acute schistosomiasis after a brief exposure (mean, 22 ± 9.5 minutes) to a high-altitude crater lake.

  7. Does Temperature and UV Exposure History Modulate the Effects of Temperature and UV Stress on Symbiodinium Growth Rates?

    EPA Science Inventory

    Temperature and ultraviolet radiation (UV) alone or in combination are known to inhibit the growth of Symbiodinium isolates. This conclusion was drawn from a number of studies having widely different exposure scenarios. Here we have examined the effects of pre-exposure acclimat...

  8. Influence of cadmium concentration and length of exposure on metabolic rate and gill Na+/K+ ATPase activity of golden shiners (Notemigonus crysoleucas).

    PubMed

    Peles, John D; Pistole, David H; Moffe, Mickey

    2012-06-01

    Although metabolic rate is considered to be useful as a general indicator of the biological effects of exposure to metals, it is seldom measured in conjunction with specific physiological, biochemical or cellular parameters. The purpose of this investigation was to examine the influence of cadmium (Cd) exposure on metabolic rate and gill Na(+)/K(+) ATPase activity in golden shiners (Notemigonus crysoleucas). Shiners were exposed to six levels of Cd (ranging from control to the maximum sublethal concentration) for 24- and 96-h periods. After 24-h, metabolic rate and Na(+)/K(+) ATPase activity of individual fish were strongly correlated. Shiners exposed to the four highest Cd concentrations (500, 800, 1100, and 1400 μg L(-1)) for 24-h exhibited a shock response that was characterized by mean values for metabolic rate and Na(+)/K(+) ATPase activity that were significantly lower compared to the control. Although results for 96-h exposures reflect a repair/recovery phase, there was no significant correlation between metabolic rate and Na(+)/K(+) ATPase activity. Metabolic rate of shiners was significantly elevated (65-100%) at all concentrations compared to the control after 96-h, whereas Na(+)/K(+) ATPase activity did not differ from the control. Elevated metabolic rate after 96-h likely reflects the influence of a variety of energetically demanding processes associated with repair and recovery.

  9. (C-11)-thymidine PET imaging as a measure of DNA synthesis rate: A preliminary quantitative study of human brain glioblastoma

    SciTech Connect

    Wong, C.Y.O.; Yung, B.C.Y.; Conti, P.

    1994-05-01

    (C-11)-Thymidine (TdR) PET imaging can potentially be used to measure the tumor proliferation in-vivo and monitor treatment. Twenty-four stereotactic brain biopsies (SBB) following in-vivo bromodeoxyuridine (BUDR) under MRI guidance were obtained to correlate with TdR PET imaging of primary glioblastoma in human brain. Following data acquisition, standard 4 by 4 pixel (2mm/pixel) regions of interest (ROIs) were placed over the tumor site based on SBB and the corresponding homologous region of contralateral normal cortices. After correcting input function for major metabolites and subtracting TdR activity in the normal side from the tumor side of the brain, 2- and 3- compartmental analysis was performed for all the ROIs. Akaike :(AIC) and Bayes (BIC) information criteria was calculated to compare these 2 kinetic models for differentiating pure blood pool effects from TdR incorporation into DNA. Of 24 SBB regions, 20 non-overlapping and corresponding ROIs in PET were identified and quantified. Eight ROIs were selected based on the AIC, BIC and root-mean-square errors (RMSE < 0.1) (4 couldn`t be modelled and 8 most likely represented blood flow effects). The percentage (%) of BUDR per high power field area %BUDR labelling. The k3, the forward phosphorylation rate (hence an index of DNA synthesis), was categorized into 2 groups according to a threshold value of %BUDR/hpfa - 5%. The tumor regions with low proliferative index (%BUDR/hpfa<5%) have significantly lower k3 than those with high proliferative index (p<0.005). We also find that k4 is at least an order less than k3, suggesting minimal effects of dephosphorylation and efflux of metabolites. We conclude that 3-compartmental, 4-parameter modeling is adequate for TdR PET studies and k3 correlates with DNA synthesis rate.

  10. A synthesis of rates and controls on elemental mercury evasion in the Great Lakes Basin.

    PubMed

    Denkenberger, Joseph S; Driscoll, Charles T; Branfireun, Brian A; Eckley, Chris S; Cohen, Mark; Selvendiran, Pranesh

    2012-02-01

    Rates of surface-air elemental mercury (Hg(0)) fluxes in the literature were synthesized for the Great Lakes Basin (GLB). For the majority of surfaces, fluxes were net positive (evasion). Digital land-cover data were combined with representative evasion rates and used to estimate annual Hg(0) evasion for the GLB (7.7 Mg/yr). This value is less than our estimate of total Hg deposition to the area (15.9 Mg/yr), suggesting the GLB is a net sink for atmospheric Hg. The greatest contributors to annual evasion for the basin are agricultural (∼55%) and forest (∼25%) land cover types, and the open water of the Great Lakes (∼15%). Areal evasion rates were similar across most land cover types (range: 7.0-21.0 μg/m(2)-yr), with higher rates associated with urban (12.6 μg/m(2)-yr) and agricultural (21.0 μg/m(2)-yr) lands. Uncertainty in these estimates could be partially remedied through a unified methodological approach to estimating Hg(0) fluxes.

  11. Identifying Housing and Meteorological Conditions Influencing Residential Air Exchange Rates in the DEARS and RIOPA Studies: Development of Distributions for Human Exposure Modeling

    EPA Science Inventory

    Appropriate prediction of residential air exchange rate (AER) is important for estimating human exposures in the residential microenvironment, as AER drives the infiltration of outdoor-generated air pollutants indoors. AER differences among homes may result from a number of fact...

  12. Work to save dose: contrasting effective dose rates from radon exposure in workplaces and residences against the backdrop of public and occupational limits

    SciTech Connect

    Whicker, Jeffrey J; Mcnaughton, Michael W

    2009-01-01

    Office workers are exposed to radon while at work and at home. Though there has been a multitude of studies reporting the measurements of radon concentrations and potential lung and effective doses associated with radon and progeny exposure in homes, similar studies on the concentrations and subsequent effective dose rates in the non-mine workplaces are lacking. Additionally, there are few, if any, comparative analyses of radon exposures at more 'typical' workplace with residential exposures within the same county. The purposes of this study were to measure radon concentrations in office and residential spaces in the same county and explore the radiation dose implications. Sixty-five track-etch detectors were deployed in office spaces and 47 were deployed in residences, all within Los Alamos County, New Mexico, USA. The sampling periods for these measurements were generally about three months. The measured concentrations were used to calculate and compare effective dose rates resulting from exposure while at work and at home. Results showed that full-time office workers receive on average about 8 times greater exposure at home than while in the office (2.3 mSv yr-! versus 0.3 mSv yr-!). The estimated effective dose rate for a more homebound person was about 3 mSv yr-!. Estimating effective doses from background radon exposure in the same county as Los Alamos National Laboratory, with thousands of'radiological workers,' highlights interesting contrasts in radiation protection standards that span public and occupational settings. For example, the effective dose rate from background radon exposure in unregulated office spaces ranged up to 1.1 mSv yr-!, which is similar to the 1 mSv yr-! threshold for regulation ofa 'radiological worker,' as defined in the Department of Energy regulations for occupational exposure. Additionally, the estimated average effective dose total of> 3 mSv yf! from radon background exposure in homes stands in contrast to the 0.1 mSv yr-! air

  13. The Unexpected Influence of Precursor Conversion Rate in the Synthesis of III-V Quantum Dots.

    PubMed

    Franke, Daniel; Harris, Daniel K; Xie, Lisi; Jensen, Klavs F; Bawendi, Moungi G

    2015-11-23

    Control of quantum dot (QD) precursor chemistry has been expected to help improve the size control and uniformity of III-V QDs such as indium phosphide and indium arsenide. Indeed, experimental results for other QD systems are consistent with the theoretical prediction that the rate of precursor conversion is an important factor controlling QD size and size distribution. We synthesized and characterized the reactivity of a variety of group-V precursors in order to determine if precursor chemistry could be used to improve the quality of III-V QDs. Despite slowing down precursor conversion rate by multiple orders of magnitude, the less reactive precursors do not yield the expected increase in size and improvement in size distribution. This result disproves the widely accepted explanation for the shortcoming of current III-V QD syntheses and points to the need for a new generalizable theoretical picture for the mechanism of QD formation and growth.

  14. Synthesis of passive microwave and radar altimeter data for estimating accumulation rates of polar snow

    NASA Technical Reports Server (NTRS)

    Davis, Curt H.

    1993-01-01

    In this paper, we compare dry-snow extinction coefficients derived from radar altimeter data with brightness temperature data from passive microwave measurements over a portion of the East Antarctic plateau. The comparison between the extinction coefficients and the brightness temperatures shows a strong negative correlation, where the correlation coefficients ranged from -0.87 to -0.95. The extinction coefficient of the dry polar snow decreases with increasing surface elevation, while the average brightness temperature increases with surface elevation. Our analysis shows that the observed trends are related to geographic variations in scattering coefficient of snow, which in turn are controlled by variations in surface temperature and snow accumulation rate. By combining information present in the extinction coefficient and brightness temperature data sets, we develop a model that can be used to obtain quantitative estimates of the accumulation rate of dry polar snow.

  15. Predicting rates of isotopic turnover across the animal kingdom: a synthesis of existing data.

    PubMed

    Thomas, Stephen M; Crowther, Thomas W

    2015-05-01

    The stable isotopes of carbon ((12)C, (13)C) and nitrogen ((14)N, (15)N) represent powerful tools in food web ecology, providing a wide range of dietary information in animal consumers. However, identifying the temporal window over which a consumer's isotopic signature reflects its diet requires an understanding of elemental incorporation, a process that varies from days to years across species and tissue types. Though theory predicts body size and temperature are likely to control incorporation rates, this has not been tested empirically across a morphologically and phylogenetically diverse range of taxa. Readily available estimates of this relationship would, however, aid in the design of stable isotope food web investigations and improve the interpretation of isotopic data collected from natural systems. Using literature-derived turnover estimates from animal species ranging in size from 1 mg to 2000 kg, we develop a predictive tool for stable isotope ecologists, allowing for estimation of incorporation rates in the structural tissues of entirely novel taxa. In keeping with metabolic scaling theory, we show that isotopic turnover rates of carbon and nitrogen in whole organisms and muscle tissue scale allometrically with body mass raised approximately to the power -0.19, an effect modulated by body temperature. This relationship did not, however, apply to incorporation rates in splanchnic tissues, which were instead dependent on the thermoregulation tactic employed by an organism, being considerably faster in endotherms than ectotherms. We believe the predictive turnover equations we provide can improve the design of experiments and interpretation of results obtained in future stable isotopic food web studies. PMID:25482029

  16. Effects of electromagnetic radiation (bright light, extremely low-frequency magnetic fields, infrared radiation) on the circadian rhythm of melatonin synthesis, rectal temperature, and heart rate.

    PubMed

    Griefahn, Barbara; Künemund, Christa; Blaszkewicz, Meinolf; Lerchl, Alexander; Degen, Gisela H

    2002-10-01

    Electromagnetic spectra reduce melatonin production and delay the nadirs of rectal temperature and heart rate. Seven healthy men (16-22 yrs) completed 4 permuted sessions. The control session consisted of a 24-hours bedrest at < 30 lux, 18 degrees C, and < 50 dBA. In the experimental sessions, either light (1500 lux), magnetic field (16.7 Hz, 0.2 mT), or infrared radiation (65 degrees C) was applied from 5 pm to 1 am. Salivary melatonin level was determined hourly, rectal temperature and heart rate were continuously recorded. Melatonin synthesis was completely suppressed by light but resumed thereafter. The nadirs of rectal temperature and heart rate were delayed. The magnetic field had no effect. Infrared radiation elevated rectal temperature and heart rate. Only bright light affected the circadian rhythms of melatonin synthesis, rectal temperature, and heart rate, however, differently thus causing a dissociation, which might enhance the adverse effects of shiftwork in the long run.

  17. Effect of insulin on the rates of synthesis and degradation of GLUT1 and GLUT4 glucose transporters in 3T3-L1 adipocytes.

    PubMed Central

    Sargeant, R J; Pâquet, M R

    1993-01-01

    The effect of continuous insulin stimulation on the rates of turnover and on the total cellular contents of the glucose-transporter proteins GLUT1 and GLUT4 in 3T3-L1 adipocytes was investigated. Pulse-and-chase studies with [35S]methionine followed by immunoprecipitation of GLUT1 and GLUT4 with isoform-specific antibodies revealed the half-lives of these proteins to be 19 h and 50 h respectively. Inclusion of 100 nM insulin in the chase medium resulted in a decrease in the half-lives of both proteins to about 15.5 h. This effect of insulin was specific for the glucose-transporter proteins, as the average half-life of all proteins was found to be 55 h both with and without insulin stimulation. The effect of insulin on the rate of synthesis of the glucose transporters was determined by the rate of incorporation of [35S]methionine. After 24 h of insulin treatment, the rate of synthesis of GLUT1 and GLUT4 were elevated over control levels by 3.5-fold and 2-fold respectively. After 72 h of treatment under the same conditions, the rate of synthesis of GLUT1 remained elevated by 2.5-fold, whereas the GLUT4 synthesis rate was not different from control levels. Western-blot analysis of total cellular membranes revealed a 4.5-fold increase in total cellular GLUT1 content and a 50% decrease in total cellular GLUT4 after 72 h of insulin treatment. These observations suggest that the rates of synthesis and degradation of GLUT1 and GLUT4 in 3T3-L1 adipocytes are regulated independently and that these cells respond to prolonged insulin treatment by altering the metabolism of GLUT1 and GLUT4 proteins in a specific manner. Images Figure 1 Figure 3 Figure 4 Figure 5 PMID:8457217

  18. Repeated measures of inflammation, blood pressure, and heart rate variability associated with personal traffic exposures in healthy adults

    EPA Science Inventory

    BACKGROUND: Previous human exposure studies of traffic-related air pollutants have demonstrated adverse health effects in human populations by comparing areas of high and low traffic, but few studies have utilized microenvironmental monitoring of pollutants at multiple traffic lo...

  19. Crystal structure of norcoclaurine-6-O-methyltransferase, a key rate-limiting step in the synthesis of benzylisoquinoline alkaloids.

    PubMed

    Robin, Adeline Y; Giustini, Cécile; Graindorge, Matthieu; Matringe, Michel; Dumas, Renaud

    2016-09-01

    Growing pharmaceutical interest in benzylisoquinoline alkaloids (BIA) coupled with their chemical complexity make metabolic engineering of microbes to create alternative platforms of production an increasingly attractive proposition. However, precise knowledge of rate-limiting enzymes and negative feedback inhibition by end-products of BIA metabolism is of paramount importance for this emerging field of synthetic biology. In this work we report the structural characterization of (S)-norcoclaurine-6-O-methyltransferase (6OMT), a key rate-limiting step enzyme involved in the synthesis of reticuline, the final intermediate to be shared between the different end-products of BIA metabolism, such as morphine, papaverine, berberine and sanguinarine. Four different crystal structures of the enzyme from Thalictrum flavum (Tf 6OMT) were solved: the apoenzyme, the complex with S-adenosyl-l-homocysteine (SAH), the complexe with SAH and the substrate and the complex with SAH and a feedback inhibitor, sanguinarine. The Tf 6OMT structural study provides a molecular understanding of its substrate specificity, active site structure and reaction mechanism. This study also clarifies the inhibition of Tf 6OMT by previously suggested feedback inhibitors. It reveals its high and time-dependent sensitivity toward sanguinarine.

  20. Crystal structure of norcoclaurine-6-O-methyltransferase, a key rate-limiting step in the synthesis of benzylisoquinoline alkaloids.

    PubMed

    Robin, Adeline Y; Giustini, Cécile; Graindorge, Matthieu; Matringe, Michel; Dumas, Renaud

    2016-09-01

    Growing pharmaceutical interest in benzylisoquinoline alkaloids (BIA) coupled with their chemical complexity make metabolic engineering of microbes to create alternative platforms of production an increasingly attractive proposition. However, precise knowledge of rate-limiting enzymes and negative feedback inhibition by end-products of BIA metabolism is of paramount importance for this emerging field of synthetic biology. In this work we report the structural characterization of (S)-norcoclaurine-6-O-methyltransferase (6OMT), a key rate-limiting step enzyme involved in the synthesis of reticuline, the final intermediate to be shared between the different end-products of BIA metabolism, such as morphine, papaverine, berberine and sanguinarine. Four different crystal structures of the enzyme from Thalictrum flavum (Tf 6OMT) were solved: the apoenzyme, the complex with S-adenosyl-l-homocysteine (SAH), the complexe with SAH and the substrate and the complex with SAH and a feedback inhibitor, sanguinarine. The Tf 6OMT structural study provides a molecular understanding of its substrate specificity, active site structure and reaction mechanism. This study also clarifies the inhibition of Tf 6OMT by previously suggested feedback inhibitors. It reveals its high and time-dependent sensitivity toward sanguinarine. PMID:27232113

  1. Effects of resistance training on the rate of muscle protein synthesis in frail elderly people.

    PubMed

    Schulte, J N; Yarasheski, K E

    2001-12-01

    Advancing age is associated with a reduction in skeletal muscle protein, muscle strength, muscle quality, and chemical modifications that may impair protein function. Sarcopenia has been coupled with physical disability, frailty, and a loss of independent function. Using stable isotope tracer methodologies and mass spectrometric detection, we observed: (a) 76-92-year-old physically frail and 62-74-year-old middle-age adults have lower mixed muscle protein synthetic rates than 20-32-year-old men and women; (b) 2 weeks and 3 months of weightlifting exercise increased the synthetic rate of myosin heavy chain (MHC) and mixed muscle proteins to a similar magnitude in frail, middle-age, and young women and men; (c) Serum myostatin-immunoreactive protein levels were elevated in physically frail women and were inversely correlated with lean mass. This suggests that the protein synthetic machinery adapts rapidly to increased contractile activity and that the adaptive response(s) are maintained even in frail elders. PMID:11915909

  2. Exposure of eggs to solar UV-B leads to reduced hatching rates in two sparid fishes, red sea bream Pagrus major and black sea bream Acanthopagrus schlegeli.

    PubMed

    Fukunishi, Y; Masuda, R; Yamashita, Y

    2010-02-01

    Hatching success was examined under exposure to solar ultraviolet radiation (UVR) using filters to give three different light conditions [C1: UV-B, UV-A and photosynthetically active radiation (PAR), C2: UV-A and PAR, C3: PAR] in red Pagrus major and black Acanthopagrus schlegeli sea bream. Hatching rate of both species was reduced by an exposure over a 2 day period to UVR and was not significantly different between two species under the three light conditions. PMID:20666911

  3. Post-veraison sunlight exposure induces MYB-mediated transcriptional regulation of anthocyanin and flavonol synthesis in berry skins of Vitis vinifera.

    PubMed

    Matus, José Tomás; Loyola, Rodrigo; Vega, Andrea; Peña-Neira, Alvaro; Bordeu, Edmundo; Arce-Johnson, Patricio; Alcalde, José Antonio

    2009-01-01

    Anthocyanins, flavan-3-ols, and flavonols are the three major classes of flavonoid compounds found in grape berry tissues. Several viticultural practices increase flavonoid content in the fruit, but the underlying genetic mechanisms responsible for these changes have not been completely deciphered. The impact of post-veraison sunlight exposure on anthocyanin and flavonol accumulation in grape berry skin and its relation to the expression of different transcriptional regulators known to be involved in flavonoid synthesis was studied. Treatments consisting of removing or moving aside the basal leaves which shade berry clusters were applied. Shading did not affect sugar accumulation or gene expression of HEXOSE TRANSPORTER 1, although in the leaf removal treatment, these events were retarded during the first weeks of ripening. Flavonols were the most drastically reduced flavonoids following shading and leaf removal treatments, related to the reduced expression of FLAVONOL SYNTHASE 4 and its putative transcriptional regulator MYB12. Anthocyanin accumulation and the expression of CHS2, LDOX, OMT, UFGT, MYBA1, and MYB5a genes were also affected. Other regulatory genes were less affected or not affected at all by these treatments. Non-transcriptional control mechanisms for flavonoid synthesis are also suggested, especially during the initial stages of ripening. Although berries from the leaf removal treatment received more light than shaded fruits, malvidin-3-glucoside and total flavonol content was reduced compared with the treatment without leaf removal. This work reveals that flavonol-related gene expression responds rapidly to field changes in light levels, as shown by the treatment in which shaded fruits were exposed to light in the late stages of ripening. Taken together, this study establishes MYB-specific responsiveness for the effect of sun exposure and sugar transport on flavonoid synthesis. PMID:19129169

  4. Post-veraison sunlight exposure induces MYB-mediated transcriptional regulation of anthocyanin and flavonol synthesis in berry skins of Vitis vinifera

    PubMed Central

    Matus, José Tomás; Loyola, Rodrigo; Vega, Andrea; Peña-Neira, Alvaro; Bordeu, Edmundo; Arce-Johnson, Patricio; Alcalde, José Antonio

    2009-01-01

    Anthocyanins, flavan-3-ols, and flavonols are the three major classes of flavonoid compounds found in grape berry tissues. Several viticultural practices increase flavonoid content in the fruit, but the underlying genetic mechanisms responsible for these changes have not been completely deciphered. The impact of post-veraison sunlight exposure on anthocyanin and flavonol accumulation in grape berry skin and its relation to the expression of different transcriptional regulators known to be involved in flavonoid synthesis was studied. Treatments consisting of removing or moving aside the basal leaves which shade berry clusters were applied. Shading did not affect sugar accumulation or gene expression of HEXOSE TRANSPORTER 1, although in the leaf removal treatment, these events were retarded during the first weeks of ripening. Flavonols were the most drastically reduced flavonoids following shading and leaf removal treatments, related to the reduced expression of FLAVONOL SYNTHASE 4 and its putative transcriptional regulator MYB12. Anthocyanin accumulation and the expression of CHS2, LDOX, OMT, UFGT, MYBA1, and MYB5a genes were also affected. Other regulatory genes were less affected or not affected at all by these treatments. Non-transcriptional control mechanisms for flavonoid synthesis are also suggested, especially during the initial stages of ripening. Although berries from the leaf removal treatment received more light than shaded fruits, malvidin-3-glucoside and total flavonol content was reduced compared with the treatment without leaf removal. This work reveals that flavonol-related gene expression responds rapidly to field changes in light levels, as shown by the treatment in which shaded fruits were exposed to light in the late stages of ripening. Taken together, this study establishes MYB-specific responsiveness for the effect of sun exposure and sugar transport on flavonoid synthesis. PMID:19129169

  5. Post-veraison sunlight exposure induces MYB-mediated transcriptional regulation of anthocyanin and flavonol synthesis in berry skins of Vitis vinifera.

    PubMed

    Matus, José Tomás; Loyola, Rodrigo; Vega, Andrea; Peña-Neira, Alvaro; Bordeu, Edmundo; Arce-Johnson, Patricio; Alcalde, José Antonio

    2009-01-01

    Anthocyanins, flavan-3-ols, and flavonols are the three major classes of flavonoid compounds found in grape berry tissues. Several viticultural practices increase flavonoid content in the fruit, but the underlying genetic mechanisms responsible for these changes have not been completely deciphered. The impact of post-veraison sunlight exposure on anthocyanin and flavonol accumulation in grape berry skin and its relation to the expression of different transcriptional regulators known to be involved in flavonoid synthesis was studied. Treatments consisting of removing or moving aside the basal leaves which shade berry clusters were applied. Shading did not affect sugar accumulation or gene expression of HEXOSE TRANSPORTER 1, although in the leaf removal treatment, these events were retarded during the first weeks of ripening. Flavonols were the most drastically reduced flavonoids following shading and leaf removal treatments, related to the reduced expression of FLAVONOL SYNTHASE 4 and its putative transcriptional regulator MYB12. Anthocyanin accumulation and the expression of CHS2, LDOX, OMT, UFGT, MYBA1, and MYB5a genes were also affected. Other regulatory genes were less affected or not affected at all by these treatments. Non-transcriptional control mechanisms for flavonoid synthesis are also suggested, especially during the initial stages of ripening. Although berries from the leaf removal treatment received more light than shaded fruits, malvidin-3-glucoside and total flavonol content was reduced compared with the treatment without leaf removal. This work reveals that flavonol-related gene expression responds rapidly to field changes in light levels, as shown by the treatment in which shaded fruits were exposed to light in the late stages of ripening. Taken together, this study establishes MYB-specific responsiveness for the effect of sun exposure and sugar transport on flavonoid synthesis.

  6. Rates of cholesterol synthesis and low-density lipoprotein uptake in the adrenal glands of the rat, hamster and rabbit in vivo.

    PubMed

    Spady, D K; Dietschy, J M

    1985-09-11

    The absolute rate of cholesterol acquisition from de novo synthesis and from receptor-dependent and receptor-independent low-density lipoprotein (LDL) uptake was determined in the adrenal glands of the rat, hamster and rabbit under in vivo conditions. The rate of incorporation of [3H]water into cholesterol in the adrenal gland was much higher in the hamster (1727 nmol/h per g) and rabbit (853 nmol/h per g) than in the rat (71 nmol/h per g). Assuming that 23 atoms of 3H are incorporated into the cholesterol molecule during its biosynthesis, the absolute rates of cholesterol synthesis were then calculated to equal 59, 29 and 2.4 micrograms/h per g of adrenal gland in the hamster, rabbit and rat, respectively. Rates of LDL-cholesterol uptake were measured using a primed continuous infusion of [14C]sucrose-labeled homologous LDL (total LDL transport) and methylated human LDL (receptor-independent LDL transport). The rate of total LDL-cholesterol uptake in the adrenal gland was much higher in the rabbit (227 micrograms/h per g) than in the rat (18 micrograms/h per g) or hamster (6 micrograms/h per g). In all three species LDL uptake was mediated largely (greater than 93%) by receptor-dependent mechanisms. In terms of total cholesterol acquisition, the hamster adrenal gland derived 10-times more cholesterol from de novo synthesis than from LDL uptake, whereas the converse was true in the rabbit. Rates of de novo synthesis and LDL-cholesterol uptake were both low in the rat adrenal gland, which is known to derive cholesterol mainly from circulating high-density lipoproteins. Thus, the adrenal gland acquires cholesterol for hormone synthesis from at least three different sources and the quantitative importance of these sources varies markedly in different animal species, including man. PMID:2992599

  7. Cumulative rate and distribution of Cd and Pb in the organs of adult male Wistar rats during oral exposure.

    PubMed

    Winiarska-Mieczan, Anna

    2014-11-01

    The degree of accumulation of Cd and Pb in the brains, spleens, lungs, hearts, livers and kidneys of adult Wistar rats was compared both for separate (Cd or Pb) and combined (Cd+Pb) oral exposure. In addition, the metals were administered either with liquids or with solid feed. Rats were exposed to low doses of metals (7mg Cd and 50mg Pb/kg feed or L of distilled water) over 6 or 12 weeks. In total the organs of rats accumulated about 0.3-0.5% Cd and 0.4-0.6% Pb supplied with food or drink. The presented studies demonstrated that the distribution of Cd and Pb in the organs is affected by: the type of exposure (separate or combined), the source of metals (feed or drinks) and the duration of exposure. It was found that simultaneous exposure to low doses of Cd and Pb supplied with food is much more hazardous than exposure to such metals supplied with water.

  8. The stoichiometry of subunit c of Escherichia coli ATP synthase is independent of its rate of synthesis.

    PubMed

    Krebstakies, Thomas; Aldag, Ingo; Altendorf, Karlheinz; Greie, Jörg-Christian; Deckers-Hebestreit, Gabriele

    2008-07-01

    Immunoblot quantitation of Escherichia coli ATP synthase isolated from atp wildtype and mutant cells, the latter comprising a reduced expression of the atpE gene coding for subunit c due to a point mutation within its Shine-Dalgarno sequence, suggested a variable stoichiometry of subunit c [Schemidt et al. (1995) Arch. Biochem. Biophys. 323, 423-428]. To study the c ring of the mutant strain and its stoichiometry in more detail, F O isolated from wildtype and mutant were investigated by quantitation, reconstitution, and cross-linking. Direct quantitation by staining with SYPRO Ruby revealed a reduction of subunit c in the mutant by a factor of 2 compared to F O subunits a and b. Rates of passive H (+) translocation correlated with the amount of subunit c present. Lower rates for mutant F O could be increased by addition of subunit c, whereas translocation rates remained constant by coreconstitution with nonfunctional subunit cD61G arguing against the presence of smaller c rings that are filled up with coreconstituted subunit c. Intermolecular cross-linking by oxidation of bicysteine-substituted subunit c ( cA21C/ cM65C) revealed an equal pattern of oligomer formation in wildtype and mutant also favoring a comparable subunit c stoichiometry. Cross-linking of membrane vesicles containing cysteine-substituted subunits a ( aN214C) and c ( cM65C) characterized the mutant F O preparation as a heterogeneous population, which consists of assembled F O and free ab 2 subcomplexes each present to approximately 50%. Thus, these data clearly demonstrate that the stoichiometry of the subunit c rings remains constant even after reduction of the synthesis of subunit c.

  9. Assessment of the point-source method for estimating dose rates to members of the public from exposure to patients with 131I thyroid treatment

    SciTech Connect

    Dewji, Shaheen Azim; Bellamy, Michael B.; Hertel, Nolan E.; Leggett, Richard Wayne; Sherbini, Sami; Saba, Mohammad S.; Eckerman, Keith F.

    2015-09-01

    The U.S. Nuclear Regulatory Commission (USNRC) initiated a contract with Oak Ridge National Laboratory (ORNL) to calculate radiation dose rates to members of the public that may result from exposure to patients recently administered iodine-131 (131I) as part of medical therapy. The main purpose was to compare dose rate estimates based on a point source and target with values derived from more realistic simulations that considered the time-dependent distribution of 131I in the patient and attenuation of emitted photons by the patient’s tissues. The external dose rate estimates were derived using Monte Carlo methods and two representations of the Phantom with Movable Arms and Legs, previously developed by ORNL and the USNRC, to model the patient and a nearby member of the public. Dose rates to tissues and effective dose rates were calculated for distances ranging from 10 to 300 cm between the phantoms and compared to estimates based on the point-source method, as well as to results of previous studies that estimated exposure from 131I patients. The point-source method overestimates dose rates to members of the public in very close proximity to an 131I patient but is a broadly accurate method of dose rate estimation at separation distances of 300 cm or more at times closer to administration.

  10. Assessment of the point-source method for estimating dose rates to members of the public from exposure to patients with 131I thyroid treatment

    DOE PAGES

    Dewji, Shaheen Azim; Bellamy, Michael B.; Hertel, Nolan E.; Leggett, Richard Wayne; Sherbini, Sami; Saba, Mohammad S.; Eckerman, Keith F.

    2015-09-01

    The U.S. Nuclear Regulatory Commission (USNRC) initiated a contract with Oak Ridge National Laboratory (ORNL) to calculate radiation dose rates to members of the public that may result from exposure to patients recently administered iodine-131 (131I) as part of medical therapy. The main purpose was to compare dose rate estimates based on a point source and target with values derived from more realistic simulations that considered the time-dependent distribution of 131I in the patient and attenuation of emitted photons by the patient’s tissues. The external dose rate estimates were derived using Monte Carlo methods and two representations of the Phantommore » with Movable Arms and Legs, previously developed by ORNL and the USNRC, to model the patient and a nearby member of the public. Dose rates to tissues and effective dose rates were calculated for distances ranging from 10 to 300 cm between the phantoms and compared to estimates based on the point-source method, as well as to results of previous studies that estimated exposure from 131I patients. The point-source method overestimates dose rates to members of the public in very close proximity to an 131I patient but is a broadly accurate method of dose rate estimation at separation distances of 300 cm or more at times closer to administration.« less

  11. Synthesis of MXene/Ag Composites for Extraordinary Long Cycle Lifetime Lithium Storage at High Rates.

    PubMed

    Zou, Guodong; Zhang, Zhiwei; Guo, Jianxin; Liu, Baozhong; Zhang, Qingrui; Fernandez, Carlos; Peng, Qiuming

    2016-08-31

    A new MXene/Ag composite was synthesized by direct reduction of a AgNO3 aqueous solution in the presence of MXene (Ti3C2(OH)0.8F1.2). The as-received MXene/Ag composite can be deemed as an excellent anode material for lithium-ion batteries, exhibiting an extraordinary long cycle lifetime with a large capacity at high charge-discharge rates. The results show that Ag self-reduction in MXene solution is related to the existence of low-valence Ti. Reversible capacities of 310 mAh·g(-1) at 1 C (theoretical value being ∼320 mAh·g(-1)), 260 mAh·g(-1) at 10 C, and 150 mAh·g(-1) at 50 C were achieved. Remarkably, the composite withstands more than 5000 cycles without capacity decay at 1-50 C. The main reasons for the long cycle life with high capacity are relevant to the reduced interface resistance and the occurrence of Ti(II) to Ti(III) during the cycle process. PMID:27517615

  12. Molten Salt Synthesis and High Rate Performance of the ‘‘Desert-Rose’’ form of LiCoO2

    SciTech Connect

    H Chen; C Grey

    2011-12-31

    The synthesis of a novel nanostructure of LiCoO{sub 2}, and its performance as a cathode for a high-rate lithium ion battery, is described. The LiCoO{sub 2} nanostructure resembles the morphology of a known natural mineral: 'desert rose' gypsum. A range of measurement techniques are used to investigate the growth mechanism of this structure and the origin of its high rate charge/discharge properties.

  13. Plutonium-aerosol emission rates and potential inhalation exposure during cleanup and treatment test at Area 11, Nevada Test Site

    SciTech Connect

    Shinn, J.H.; Homan, D.N.

    1985-08-13

    A Cleanup and Treatment (CAT) test was conducted in 1981 at Area 11, Nevada Test Site. Its purpose was to evaluate the effectiveness of using a large truck-mounted vacuum cleaner similar to those used to clean paved streets for cleaning radiological contamination from the surface of desert soils. We found that four passes with the vehicle removed 97% of the alpha contamination and reduced resuspension by 99.3 to 99.7%. Potential exposure to cleanup workers was slight when compared to natural background exposure. 7 refs., 1 fig., 2 tabs.

  14. Assessment of dietary exposure to flavouring substances via consumption of flavoured teas. Part II: transfer rates of linalool and linalyl esters into Earl Grey tea infusions.

    PubMed

    Orth, Anne-Marie; Poplacean, Iulia; Fastowski, Oxana; Engel, Karl-Heinz

    2014-01-01

    The assessment of dietary exposure via the consumption of flavoured foods is a key element of the safety evaluation of flavouring substances. Linalyl acetate and linalool are the major flavouring substances in Earl Grey teas; the objective of this study was to determine their transfer rates from the tea leaves into the tea beverage upon preparation of a hot water infusion. Spiking experiments revealed a transfer rate of 66% for linalool. In contrast, the transfer rate for linalyl acetate was only 1.9%; in turn, the hydrolysis product linalool (17.0%) and a spectrum (19.9%) of degradation and rearrangement products (monoterpene alcohols, esters and hydrocarbons) were present in the tea beverage. The transfer rates were shown to be proportional to the length of the infusion. The impact of the hot water treatment on the enantiomeric compositions of linalyl acetate and linalool was determined, and structure-dependent experiments were performed by variation of the acyl and the alcohol moiety of the monoterpene ester. Comparative dietary exposure assessments demonstrated the need to take correction factors based on the experimentally determined transfer rates into account. Based on tea consumption data from the UK National Diet and Nutrition Survey (2000/2001), the exposure to linalyl acetate ranges from 0.2 mg day(-1) (average) to 1.8 mg day(-1) (high). The corresponding values for linalool are 4.2 mg day(-1) (average) and 46.6 mg day(-1) (high). The exposure of linalool via consumption of the tea beverage is approximately 26 times higher than that of linalyl acetate, although in the flavoured tea leaves the median content of linalyl acetate is approximately 1.8 times higher than that of linalool.

  15. Translation initiation rate determines the impact of ribosome stalling on bacterial protein synthesis.

    PubMed

    Hersch, Steven J; Elgamal, Sara; Katz, Assaf; Ibba, Michael; Navarre, William Wiley

    2014-10-10

    Ribosome stalling during translation can be caused by a number of characterized mechanisms. However, the impact of elongation stalls on protein levels is variable, and the reasons for this are often unclear. To investigate this relationship, we examined the bacterial translation elongation factor P (EF-P), which plays a critical role in rescuing ribosomes stalled at specific amino acid sequences including polyproline motifs. In previous proteomic analyses of both Salmonella and Escherichia coli efp mutants, it was evident that not all proteins containing a polyproline motif were dependent on EF-P for efficient expression in vivo. The α- and β-subunits of ATP synthase, AtpA and AtpD, are translated from the same mRNA transcript, and both contain a PPG motif; however, proteomic analysis revealed that AtpD levels are strongly dependent on EF-P, whereas AtpA levels are independent of EF-P. Using these model proteins, we systematically determined that EF-P dependence is strongly influenced by elements in the 5'-untranslated region of the mRNA. By mutating either the Shine-Dalgarno sequence or the start codon, we find that EF-P dependence correlates directly with the rate of translation initiation where strongly expressed proteins show the greatest dependence on EF-P. Our findings demonstrate that polyproline-induced stalls exert a net effect on protein levels only if they limit translation significantly more than initiation. This model can be generalized to explain why sequences that induce pauses in translation elongation to, for example, facilitate folding do not necessarily exact a penalty on the overall production of the protein. PMID:25148683

  16. In-situ Real-Time Monitoring of Volatile Organic Compound Exposure and Heart Rate Variability for Patients with Multiple Chemical Sensitivity

    PubMed Central

    Mizukoshi, Atsushi; Kumagai, Kazukiyo; Yamamoto, Naomichi; Noguchi, Miyuki; Yoshiuchi, Kazuhiro; Kumano, Hiroaki; Sakabe, Kou; Yanagisawa, Yukio

    2015-01-01

    In-situ real-time monitoring of volatile organic compound (VOC) exposure and heart rate variability (HRV) were conducted for eight multiple chemical sensitivity (MCS) patients using a VOC monitor, a Holter monitor, and a time-activity questionnaire for 24 h to identify the relationship between VOC exposure, biological effects, and subjective symptoms in actual life. The results revealed no significantly different parameters for averaged values such as VOC concentration, HF (high frequency), and LF (low frequency) to HF ratio compared with previous data from healthy subjects (Int. J. Environ. Res. Public Health 2010, 7, 4127–4138). Significant negative correlations for four subjects were observed between HF and amounts of VOC change. These results suggest that some patients show inhibition of parasympathetic activities along with VOC exposure as observed in healthy subjects. Comparing the parameters during subjective symptoms and normal condition, VOC concentration and/or VOC change were high except for one subject. HF values were low for five subjects during subjective symptoms. Examining the time-series data for VOC exposure and HF of each subject showed that the subjective symptoms, VOC exposure, and HF seemed well related in some symptoms. Based on these characteristics, prevention measures of symptoms for each subject may be proposed. PMID:26445055

  17. Identifying housing and meteorological conditions influencing residential air exchange rates in the DEARS and RIOPA studies: development of distributions for human exposure modeling.

    PubMed

    Isaacs, Kristin; Burke, Janet; Smith, Luther; Williams, Ronald

    2013-01-01

    Appropriate prediction of residential air exchange rate (AER) is important for estimating human exposures in the residential microenvironment, as AER drives the infiltration of outdoor-generated air pollutants indoors. AER differences among homes may result from a number of factors, including housing characteristics and meteorological conditions. Residential AER data collected in the Detroit Exposure and Aerosol Research Study (DEARS) and the Relationships of Indoor, Outdoor and Personal Air (RIOPA) study were analyzed to determine whether the influence of a number of housing and meteorological conditions on AER were consistent across four cities in different regions of the United States (Detroit MI, Elizabeth NJ, Houston TX, Los Angeles, CA). Influential factors were identified and used as binning variables for deriving final AER distributions for the use in exposure modeling. In addition, both between-home and within-home variance in AER in DEARS were quantified with the goal of identifying reasonable AER resampling frequencies for use in longitudinal exposure modeling efforts. The results of this analysis indicate that residential AER is depended on ambient temperature, the presence (or not) of central air conditioning, and the age of the home. Furthermore, between-home variability in AER accounted for the majority (67%) of the total variance in AER for Detroit homes, indicating lower within-home variability. These findings are compared with other previously published AER distributions, and the implications for exposure modeling are discussed.

  18. DNA repair and recovery of RNA synthesis following exposure to ultraviolet light are delayed in long genes.

    PubMed

    Andrade-Lima, Leonardo C; Veloso, Artur; Paulsen, Michelle T; Menck, Carlos F M; Ljungman, Mats

    2015-03-11

    The kinetics of DNA repair and RNA synthesis recovery in human cells following UV-irradiation were assessed using nascent RNA Bru-seq and quantitative long PCR. It was found that UV light inhibited transcription elongation and that recovery of RNA synthesis occurred as a wave in the 5'-3' direction with slow recovery and TC-NER at the 3' end of long genes. RNA synthesis resumed fully at the 3'-end of genes after a 24 h recovery in wild-type fibroblasts, but not in cells deficient in transcription-coupled nucleotide excision repair (TC-NER) or global genomic NER (GG-NER). Different transcription recovery profiles were found for individual genes but these differences did not fully correlate to differences in DNA repair of these genes. Our study gives the first genome-wide view of how UV-induced lesions affect transcription and how the recovery of RNA synthesis of large genes are particularly delayed by the apparent lack of resumption of transcription by arrested polymerases.

  19. PM2.5 EXPOSURE CHANGES HEART RATE VARIABILITY (HRV) AND BLOOD PARAMETERS IN STATE HIGHWAY PATROL TROOPERS

    EPA Science Inventory

    Epidemiological studies show an association between ambient particulate matter PM and cardiovascular mortality. Panel and controlled exposure studies report PM-associated changes in HRV and blood factors involved in clotting and inflammation. We investigated the effects of in-veh...

  20. Hurricane exposure and county fetal death rates, utilization of a county environmental quality index for confounding control.

    EPA Science Inventory

    The effects of natural disasters on public health are a rising concern, with increasing severity of disaster events. Many disaster studies utilize county-level analysis, however most do not control for county level environmental factors. Hurricane exposure during pregnancy could ...

  1. THE UNIQUE VALUE OF BREATH BIOMARKERS FOR ESTIMATING PHARMACOKINETIC RATE CONSTANTS AND BODY BURDEN FROM ENVIRONMENTAL EXPOSURES

    EPA Science Inventory

    Although detection of breath odor is the oldest of the medical diagnostic techniques, blood and urine biomarker measurements are the current "gold standard" for modern exposure and health assessments. Of late, it has been recognized that collecting exhaled breath is an attractiv...

  2. Exposure-Specific and Age-Specific Attack Rates for Ebola Virus Disease in Ebola-Affected Households, Sierra Leone

    PubMed Central

    Bower, Hilary; Johnson, Sembia; Bangura, Mohamed S.; Kamara, Alie Joshua; Kamara, Osman; Mansaray, Saidu H.; Sesay, Daniel; Turay, Cecilia; Checchi, Francesco

    2016-01-01

    Using histories of household members of Ebola virus disease (EVD) survivors in Sierra Leone, we calculated risk of EVD by age and exposure level, adjusting for confounding and clustering, and estimated relative risks. Of 937 household members in 94 households, 448 (48%) had had EVD. Highly correlated with exposure, EVD risk ranged from 83% for touching a corpse to 8% for minimal contact and varied by age group: 43% for children <2 years of age; 30% for those 5–14 years of age; and >60% for adults >30 years of age. Compared with risk for persons 20–29 years of age, exposure-adjusted relative risks were lower for those 5–9 (0.70), 10–14 (0.64), and 15–19 (0.71) years of age but not for children <2 (0.92) or 2–4 (0.97) years of age. Lower risk for 5–19-year-olds, after adjustment for exposure, suggests decreased susceptibility in this group. PMID:27144428

  3. Exposure-Specific and Age-Specific Attack Rates for Ebola Virus Disease in Ebola-Affected Households, Sierra Leone.

    PubMed

    Bower, Hilary; Johnson, Sembia; Bangura, Mohamed S; Kamara, Alie Joshua; Kamara, Osman; Mansaray, Saidu H; Sesay, Daniel; Turay, Cecilia; Checchi, Francesco; Glynn, Judith R

    2016-08-01

    Using histories of household members of Ebola virus disease (EVD) survivors in Sierra Leone, we calculated risk of EVD by age and exposure level, adjusting for confounding and clustering, and estimated relative risks. Of 937 household members in 94 households, 448 (48%) had had EVD. Highly correlated with exposure, EVD risk ranged from 83% for touching a corpse to 8% for minimal contact and varied by age group: 43% for children <2 years of age; 30% for those 5-14 years of age; and >60% for adults >30 years of age. Compared with risk for persons 20-29 years of age, exposure-adjusted relative risks were lower for those 5-9 (0.70), 10-14 (0.64), and 15-19 (0.71) years of age but not for children <2 (0.92) or 2-4 (0.97) years of age. Lower risk for 5-19-year-olds, after adjustment for exposure, suggests decreased susceptibility in this group. PMID:27144428

  4. Links between Self-Reported Media Violence Exposure and Teacher Ratings of Aggression and Prosocial Behavior among German Adolescents

    ERIC Educational Resources Information Center

    Krahe, Barbara; Moller, Ingrid

    2011-01-01

    The relations between adolescents' habitual usage of media violence and their tendency to engage in aggressive and prosocial behavior in a school setting were examined in a cross-sectional study with 1688 7th and 8th graders in Germany who completed measures of violent media exposure and normative acceptance of aggression. For each participant,…

  5. Rates of insulin secretion in INS-1 cells are enhanced by coupling to anaplerosis and Kreb's cycle flux independent of ATP synthesis

    SciTech Connect

    Cline, Gary W.; Pongratz, Rebecca L.; Zhao, Xiaojian; Papas, Klearchos K.

    2011-11-11

    Highlights: Black-Right-Pointing-Pointer We studied media effects on mechanisms of insulin secretion of INS-1 cells. Black-Right-Pointing-Pointer Insulin secretion was higher in DMEM than KRB despite identical ATP synthesis rates. Black-Right-Pointing-Pointer Insulin secretion rates correlated with rates of anaplerosis and TCA cycle. Black-Right-Pointing-Pointer Mitochondria metabolism and substrate cycles augment secretion signal of ATP. -- Abstract: Mechanistic models of glucose stimulated insulin secretion (GSIS) established in minimal media in vitro, may not accurately describe the complexity of coupling metabolism with insulin secretion that occurs in vivo. As a first approximation, we have evaluated metabolic pathways in a typical growth media, DMEM as a surrogate in vivo medium, for comparison to metabolic fluxes observed under the typical experimental conditions using the simple salt-buffer of KRB. Changes in metabolism in response to glucose and amino acids and coupling to insulin secretion were measured in INS-1 832/13 cells. Media effects on mitochondrial function and the coupling efficiency of oxidative phosphorylation were determined by fluorometrically measured oxygen consumption rates (OCRs) combined with {sup 31}P NMR measured rates of ATP synthesis. Substrate preferences and pathways into the TCA cycle, and the synthesis of mitochondrial 2nd messengers by anaplerosis were determined by {sup 13}C NMR isotopomer analysis of the fate of [U-{sup 13}C] glucose metabolism. Despite similar incremental increases in insulin secretion, the changes of OCR in response to increasing glucose from 2.5 to 15 mM were blunted in DMEM relative to KRB. Basal and stimulated rates of insulin secretion rates were consistently higher in DMEM, while ATP synthesis rates were identical in both DMEM and KRB, suggesting greater mitochondrial uncoupling in DMEM. The relative rates of anaplerosis, and hence synthesis and export of 2nd messengers from the mitochondria were found

  6. Long-term slip rate of the southern San Andreas Fault, from 10Be-26Al surface exposure dating of an offset alluvial fan

    SciTech Connect

    der Woerd, J v; Klinger, Y; Sieh, K; Tapponnier, P; Ryerson, F; M?riaux, A

    2006-01-13

    We determine the long-term slip rate of the southern San Andreas Fault in the southeastern Indio Hills using {sup 10}Be and {sup 26}Al isotopes to date an offset alluvial fan surface. Field mapping complemented with topographic data, air photos and satellite images allow to precisely determine piercing points across the fault zone that are used to measure an offset of 565 {+-} 80 m. A total of twenty-six quartz-rich cobbles from three different fan surfaces were collected and dated. The tight cluster of nuclide concentrations from 19 samples out of 20 from the offset fan surface implies a simple exposure history, negligible prior exposure and erosion, and yield an age of 35.5 {+-} 2.5 ka. The long-term slip rate of the San Andreas Fault south of Biskra Palms is thus 15.9 {+-} 3.4 mm/yr. This rate is about 10 mm/yr slower than geological (0-14 ka) and short-term geodetic estimates for this part of the San Andreas Fault implying changes in slip rate or in faulting behavior. This result puts new constraints on the slip rate of the San Jacinto and on the Eastern California Shear Zone for the last 35 ka. Our study shows that more sites along the major faults of southern California need to be targeted to better constrain the slip-rates over different time scales.

  7. Reduced rate of adenosine triphosphate synthesis by in vivo 31P nuclear magnetic resonance spectroscopy and downregulation of PGC-1beta in distal skeletal muscle following burn.

    PubMed

    Tzika, A Aria; Mintzopoulos, Dionyssios; Padfield, Katie; Wilhelmy, Julie; Mindrinos, Michael N; Yu, Hongue; Cao, Haihui; Zhang, Qunhao; Astrakas, Loukas G; Zhang, Jiangwen; Yu, Yong-Ming; Rahme, Laurence G; Tompkins, Ronald G

    2008-02-01

    Using a mouse model of burn trauma, we tested the hypothesis that severe burn trauma corresponding to 30% of total body surface area (TBSA) causes reduction in adenosine triphosphate (ATP) synthesis in distal skeletal muscle. We employed in vivo 31P nuclear magnetic resonance (NMR) in intact mice to assess the rate of ATP synthesis, and characterized the concomitant gene expression patterns in skeletal muscle in burned (30% TBSA) versus control mice. Our NMR results showed a significantly reduced rate of ATP synthesis and were complemented by genomic results showing downregulation of the ATP synthase mitochondrial F1 F0 complex and PGC-1beta gene expression. Our findings suggest that inflammation and muscle atrophy in burns are due to a reduced ATP synthesis rate that may be regulated upstream by PGC-1beta. These findings implicate mitochondrial dysfunction in distal skeletal muscle following burn injury. That PGC-1beta is a highly inducible factor in most tissues and responds to common calcium and cyclic adenosine monophosphate (cAMP) signaling pathways strongly suggests that it may be possible to develop drugs that can induce PGC-1beta.

  8. Production Rates of Noble Gases in the Near-Surface Layers of Europa by Energetic Charged Particles and the Potential for Determining Exposure Ages

    NASA Technical Reports Server (NTRS)

    Swindle, T. D.; Reedy, R. C.; Masarik, J.

    2003-01-01

    The surface of Europa is expected to be extremely active, undergoing tectonic and/or tidal geological activity and sputtering/ deposition, as well as impact cratering. Determination of the actual age of the surface at one or more places would greatly simplify trying to sort out what processes are occurring, and at what rate. If there is K present, as the spectral and compositional modeling discussed predict, it should be possible, in principle, to determine K-Ar crystallization ages. Whether or not there is K present, a consideration of the environment suggests we can determine an energetic particle exposure age if we can make in situ measurements of the abundances of major elements and of noble gas isotopes. This requires instrumentation that is within reach of current technology. In this paper, we calculate production rates for noble-gas isotopes in a simplified Europan surface, to quantify the amount of light noble gases produced by exposure to energetic particles.

  9. Facile Hydrothermal Synthesis of VS2/Graphene Nanocomposites with Superior High-Rate Capability as Lithium-Ion Battery Cathodes.

    PubMed

    Fang, Wenying; Zhao, Hongbin; Xie, Yanping; Fang, Jianhui; Xu, Jiaqiang; Chen, Zhongwei

    2015-06-17

    In this study, a facile one-pot process for the synthesis of hierarchical VS2/graphene nanosheets (VS2/GNS) composites based on the coincident interaction of VS2 and reduced graphene oxide (rGO) sheets in the presence of cetyltrimethylammonium bromide is developed for the first time. The nanocomposites possess a hierarchical structure of 50 nm VS2 sheets in thickness homogeneously anchored on graphene. The VS2/GNS nanocomposites exhibit an impressive high-rate capability and good cyclic stability as a cathode material for Li-ion batteries, which retain 89.3% of the initial capacity 180.1 mAh g(-1) after 200 cycles at 0.2 C. Even at 20 C, the composites still deliver a high capacity of 114.2 mAh g(-1) corresponding to 62% of the low-rate capacity. Expanded studies show that VS2/GNS, as an anode material, also has a good reversible performance with 528 mAh g(-1) capacity after 100 cycles at 200 mA g(-1). The excellent electrochemical performance of the composites for reversible Li+ storage should be attributed to the exceptional interaction between VS2 and GNS that enabled fast electron transport between graphene and VS2, facile Li-ion diffusion within the electrode. Moreover, GNS provides a topological and structural template for the nucleation and growth of two-dimensional VS2 nanosheets and acted as buffer matrix to relieve the volume expansion/contraction of VS2 during the electrochemical charge/discharge, facilitating improved cycling stability. The VS2/GNS composites may be promising electrode materials for the next generation of rechargeable lithium ion batteries.

  10. Monte Carlo Population Synthesis of Post-common-envelope White Dwarf Binaries and Type Ia supernova Rate

    NASA Astrophysics Data System (ADS)

    Ablimit, Iminhaji; Maeda, Keiichi; Li, Xiang-Dong

    2016-07-01

    Binary population synthesis (BPS) studies provide a comprehensive way to understand the evolution of binaries and their end products. Close white dwarf (WD) binaries have crucial characteristics for examining the influence of unresolved physical parameters on binary evolution. In this paper, we perform Monte Carlo BPS simulations, investigating the population of WD/main-sequence (WD/MS) binaries and double WD binaries using a publicly available binary star evolution code under 37 different assumptions for key physical processes and binary initial conditions. We considered different combinations of the binding energy parameter (λ g: considering gravitational energy only; λ b: considering both gravitational energy and internal energy; and λ e: considering gravitational energy, internal energy, and entropy of the envelope, with values derived from the MESA code), CE efficiency, critical mass ratio, initial primary mass function, and metallicity. We find that a larger number of post-CE WD/MS binaries in tight orbits are formed when the binding energy parameters are set by λ e than in those cases where other prescriptions are adopted. We also determine the effects of the other input parameters on the orbital periods and mass distributions of post-CE WD/MS binaries. As they contain at least one CO WD, double WD systems that evolved from WD/MS binaries may explode as type Ia supernovae (SNe Ia) via merging. In this work, we also investigate the frequency of two WD mergers and compare it to the SNe Ia rate. The calculated Galactic SNe Ia rate with λ = λ e is comparable to the observed SNe Ia rate, ˜8.2 × 10‑5 yr‑1 – ˜4 × 10‑3 yr‑1 depending on the other BPS parameters, if a DD system does not require a mass ratio higher than ˜0.8 to become an SNe Ia. On the other hand, a violent merger scenario, which requires the combined mass of two CO WDs ≥ 1.6M ⊙ and a mass ratio >0.8, results in a much lower SNe Ia rate than is observed.

  11. Monte Carlo Population Synthesis of Post-common-envelope White Dwarf Binaries and Type Ia supernova Rate

    NASA Astrophysics Data System (ADS)

    Ablimit, Iminhaji; Maeda, Keiichi; Li, Xiang-Dong

    2016-07-01

    Binary population synthesis (BPS) studies provide a comprehensive way to understand the evolution of binaries and their end products. Close white dwarf (WD) binaries have crucial characteristics for examining the influence of unresolved physical parameters on binary evolution. In this paper, we perform Monte Carlo BPS simulations, investigating the population of WD/main-sequence (WD/MS) binaries and double WD binaries using a publicly available binary star evolution code under 37 different assumptions for key physical processes and binary initial conditions. We considered different combinations of the binding energy parameter (λ g: considering gravitational energy only; λ b: considering both gravitational energy and internal energy; and λ e: considering gravitational energy, internal energy, and entropy of the envelope, with values derived from the MESA code), CE efficiency, critical mass ratio, initial primary mass function, and metallicity. We find that a larger number of post-CE WD/MS binaries in tight orbits are formed when the binding energy parameters are set by λ e than in those cases where other prescriptions are adopted. We also determine the effects of the other input parameters on the orbital periods and mass distributions of post-CE WD/MS binaries. As they contain at least one CO WD, double WD systems that evolved from WD/MS binaries may explode as type Ia supernovae (SNe Ia) via merging. In this work, we also investigate the frequency of two WD mergers and compare it to the SNe Ia rate. The calculated Galactic SNe Ia rate with λ = λ e is comparable to the observed SNe Ia rate, ˜8.2 × 10-5 yr-1 - ˜4 × 10-3 yr-1 depending on the other BPS parameters, if a DD system does not require a mass ratio higher than ˜0.8 to become an SNe Ia. On the other hand, a violent merger scenario, which requires the combined mass of two CO WDs ≥ 1.6M ⊙ and a mass ratio >0.8, results in a much lower SNe Ia rate than is observed.

  12. Estimated dose rates to members of the public from external exposure to patients with 131I thyroid treatment

    SciTech Connect

    Dewji, S.; Bellamy, M.; Hertel, N.; Leggett, R.; Sherbini, S.; Saba, M.; Eckerman, K.

    2015-03-25

    The purpose of this study is to estimate dose rates that may result from exposure to patients who had been administered iodine-131 (131I) as part of medical therapy were calculated. These effective dose rate estimates were compared with simplified assumptions under United States Nuclear Regulatory Commission Regulatory Guide 8.39, which does not consider body tissue attenuation nor time-dependent redistribution and excretion of the administered 131I. Methods: Dose rates were estimated for members of the public potentially exposed to external irradiation from patients recently treated with 131I. Tissue attenuation and iodine biokinetics were considered in the patient in a larger comprehensive effort to improve external dose rate estimates. The external dose rate estimates are based on Monte Carlo simulations using the Phantom with Movable Arms and Legs (PIMAL), previously developed by Oak Ridge National Laboratory and the United States Nuclear Regulatory Commission. PIMAL was employed to model the relative positions of the 131I patient and members of the public in three exposure scenarios: (1) traveling on a bus in a total of six seated or standing permutations, (2) two nursing home cases where a caregiver is seated at 30 cm from the patient’s bedside and a nursing home resident seated 250 cm away from the patient in an adjacent bed, and (3) two hotel cases where the patient and a guest are in adjacent rooms with beds on opposite sides of the common wall, with the patient and guest both in bed and either seated back-to-back or lying head to head. The biokinetic model predictions of the retention and distribution of 131I in the patient assumed a single voiding of urinary bladder contents that occurred during the trip at 2, 4, or 8 h after 131I administration for the public transportation cases, continuous first-order voiding for the nursing home cases, and regular periodic voiding at 4, 8, or 12 h

  13. The effect of linoleic acid on the whole body synthesis rates of polyunsaturated fatty acids from α-linolenic acid and linoleic acid in free-living rats.

    PubMed

    Domenichiello, Anthony F; Kitson, Alex P; Chen, Chuck T; Trépanier, Marc-Olivier; Stavro, P Mark; Bazinet, Richard P

    2016-04-01

    Docosahexaenoic acid (DHA) is thought to be important for brain function. The main dietary source of DHA is fish, however, DHA can also be synthesized from precursor omega-3 polyunsaturated fatty acids (n-3 PUFA), the most abundantly consumed being α-linolenic acid (ALA). The enzymes required to synthesize DHA from ALA are also used to synthesize longer chain omega-6 (n-6) PUFA from linoleic acid (LNA). The large increase in LNA consumption that has occurred over the last century has led to concern that LNA and other n-6 PUFA outcompete n-3 PUFA for enzymes involved in DHA synthesis, and therefore, decrease overall DHA synthesis. To assess this, rats were fed diets containing LNA at 53 (high LNA diet), 11 (medium LNA diet) or 1.5% (low LNA diet) of the fatty acids with ALA being constant across all diets (approximately 4% of the fatty acids). Rats were maintained on these diets from weaning for 8 weeks, at which point they were subjected to a steady-state infusion of labeled ALA and LNA to measure DHA and arachidonic acid (ARA) synthesis rates. DHA and ARA synthesis rates were generally highest in rats fed the medium and high LNA diets, while the plasma half-life of DHA was longer in rats fed the low LNA diet. Therefore, increasing dietary LNA, in rats, did not impair DHA synthesis; however, low dietary LNA led to a decrease in DHA synthesis with tissue concentrations of DHA possibly being maintained by a longer DHA half-life.

  14. Enhanced GSH synthesis by Bisphenol A exposure promoted DNA methylation process in the testes of adult rare minnow Gobiocypris rarus.

    PubMed

    Yuan, Cong; Zhang, Yingying; Liu, Yan; Zhang, Ting; Wang, Zaizhao

    2016-09-01

    DNA methylation is a commonly studied epigenetic modification. The mechanism of BPA on DNA methylation is poorly understood. The present study aims to explore whether GSH synthesis affects DNA methylation in the testes of adult male rare minnow Gobiocypris rarus in response to Bisphenol A (BPA). Male G. rarus was exposed to 1, 15 and 225μgL(-1) BPA for 7 days. The levels of global DNA methylation, hydrogen peroxide (H2O2) and glutathione (GSH) in the testes were analyzed. Meanwhile, the levels of enzymes involved in DNA methylation and de novo GSH synthesis, and the substrate contents for GSH production were measured. Furthermore, gene expression profiles of the corresponding genes of all studied enzymes were analyzed. Results indicated that BPA at 15 and 225μgL(-1) caused hypermethylation of global DNA in the testes. The 15μgL(-1) BPA resulted in significant decrease of ten-eleven translocation proteins (TETs) while 225μgL(-1) BPA caused significant increase of DNA methyltransferase proteins (DNMTs). Moreover, 225μgL(-1) BPA caused significant increase of H2O2 and GSH levels, and the de novo GSH synthesis was enhanced. These results indicated that the significant decrease of the level of TETs may be sufficient to cause the DNA hypermethylation by 15μgL(-1) BPA. However, the significantly increased of DNMTs contributed to the significant increase of DNA methylation levels by 225μgL(-1) BPA. Moreover, the elevated de novo GSH synthesis may promote the DNA methylation process. PMID:27474941

  15. Aflatoxin-Exposure of Vibrio gazogenes as a Novel System for the Generation of Aflatoxin Synthesis Inhibitors

    PubMed Central

    Gummadidala, Phani M.; Chen, Yung Pin; Beauchesne, Kevin R.; Miller, Kristen P.; Mitra, Chandrani; Banaszek, Nora; Velez-Martinez, Michelle; Moeller, Peter D. R.; Ferry, John L.; Decho, Alan W.; Chanda, Anindya

    2016-01-01

    Aflatoxin is a mycotoxin and a secondary metabolite, and the most potent known liver carcinogen that contaminates several important crops, and represents a significant threat to public health and the economy. Available approaches reported thus far have been insufficient to eliminate this threat, and therefore provide the rational to explore novel methods for preventing aflatoxin accumulation in the environment. Many terrestrial plants and microbes that share ecological niches and encounter the aflatoxin producers have the ability to synthesize compounds that inhibit aflatoxin synthesis. However, reports of natural aflatoxin inhibitors from marine ecosystem components that do not share ecological niches with the aflatoxin producers are rare. Here, we show that a non-pathogenic marine bacterium, Vibrio gazogenes, when exposed to low non-toxic doses of aflatoxin B1, demonstrates a shift in its metabolic output and synthesizes a metabolite fraction that inhibits aflatoxin synthesis without affecting hyphal growth in the model aflatoxin producer, Aspergillus parasiticus. The molecular mass of the predominant metabolite in this fraction was also different from the known prodigiosins, which are the known antifungal secondary metabolites synthesized by this Vibrio. Gene expression analyses using RT-PCR demonstrate that this metabolite fraction inhibits aflatoxin synthesis by down-regulating the expression of early-, middle-, and late- growth stage aflatoxin genes, the aflatoxin pathway regulator, aflR and one global regulator of secondary metabolism, laeA. Our study establishes a novel system for generation of aflatoxin synthesis inhibitors, and emphasizes the potential of the under-explored Vibrio’s silent genome for generating new modulators of fungal secondary metabolism. PMID:27375561

  16. Alcohol Ingestion Impairs Maximal Post-Exercise Rates of Myofibrillar Protein Synthesis following a Single Bout of Concurrent Training

    PubMed Central

    Parr, Evelyn B.; Camera, Donny M.; Areta, José L.; Burke, Louise M.; Phillips, Stuart M.; Hawley, John A.; Coffey, Vernon G.

    2014-01-01

    Introduction The culture in many team sports involves consumption of large amounts of alcohol after training/competition. The effect of such a practice on recovery processes underlying protein turnover in human skeletal muscle are unknown. We determined the effect of alcohol intake on rates of myofibrillar protein synthesis (MPS) following strenuous exercise with carbohydrate (CHO) or protein ingestion. Methods In a randomized cross-over design, 8 physically active males completed three experimental trials comprising resistance exercise (8×5 reps leg extension, 80% 1 repetition maximum) followed by continuous (30 min, 63% peak power output (PPO)) and high intensity interval (10×30 s, 110% PPO) cycling. Immediately, and 4 h post-exercise, subjects consumed either 500 mL of whey protein (25 g; PRO), alcohol (1.5 g·kg body mass−1, 12±2 standard drinks) co-ingested with protein (ALC-PRO), or an energy-matched quantity of carbohydrate also with alcohol (25 g maltodextrin; ALC-CHO). Subjects also consumed a CHO meal (1.5 g CHO·kg body mass−1) 2 h post-exercise. Muscle biopsies were taken at rest, 2 and 8 h post-exercise. Results Blood alcohol concentration was elevated above baseline with ALC-CHO and ALC-PRO throughout recovery (P<0.05). Phosphorylation of mTORSer2448 2 h after exercise was higher with PRO compared to ALC-PRO and ALC-CHO (P<0.05), while p70S6K phosphorylation was higher 2 h post-exercise with ALC-PRO and PRO compared to ALC-CHO (P<0.05). Rates of MPS increased above rest for all conditions (∼29–109%, P<0.05). However, compared to PRO, there was a hierarchical reduction in MPS with ALC-PRO (24%, P<0.05) and with ALC-CHO (37%, P<0.05). Conclusion We provide novel data demonstrating that alcohol consumption reduces rates of MPS following a bout of concurrent exercise, even when co-ingested with protein. We conclude that alcohol ingestion suppresses the anabolic response in skeletal muscle and may therefore impair recovery and adaptation to

  17. A Novel Pulse-Chase SILAC Strategy Measures Changes in Protein Decay and Synthesis Rates Induced by Perturbation of Proteostasis with an Hsp90 Inhibitor

    PubMed Central

    Fierro-Monti, Ivo; Racle, Julien; Hernandez, Celine; Waridel, Patrice; Hatzimanikatis, Vassily; Quadroni, Manfredo

    2013-01-01

    Standard proteomics methods allow the relative quantitation of levels of thousands of proteins in two or more samples. While such methods are invaluable for defining the variations in protein concentrations which follow the perturbation of a biological system, they do not offer information on the mechanisms underlying such changes. Expanding on previous work [1], we developed a pulse-chase (pc) variant of SILAC (stable isotope labeling by amino acids in cell culture). pcSILAC can quantitate in one experiment and for two conditions the relative levels of proteins newly synthesized in a given time as well as the relative levels of remaining preexisting proteins. We validated the method studying the drug-mediated inhibition of the Hsp90 molecular chaperone, which is known to lead to increased synthesis of stress response proteins as well as the increased decay of Hsp90 “clients”. We showed that pcSILAC can give information on changes in global cellular proteostasis induced by treatment with the inhibitor, which are normally not captured by standard relative quantitation techniques. Furthermore, we have developed a mathematical model and computational framework that uses pcSILAC data to determine degradation constants kd and synthesis rates Vs for proteins in both control and drug-treated cells. The results show that Hsp90 inhibition induced a generalized slowdown of protein synthesis and an increase in protein decay. Treatment with the inhibitor also resulted in widespread protein-specific changes in relative synthesis rates, together with variations in protein decay rates. The latter were more restricted to individual proteins or protein families than the variations in synthesis. Our results establish pcSILAC as a viable workflow for the mechanistic dissection of changes in the proteome which follow perturbations. Data are available via ProteomeXchange with identifier PXD000538. PMID:24312217

  18. Population growth rate and genetic variability of small and large populations of Red flour beetle (Tribolium castaneum) following multigenerational exposure to copper.

    PubMed

    Laskowski, Ryszard; Radwan, Jacek; Kuduk, Katarzyna; Mendrok, Magdalena; Kramarz, Paulina

    2015-07-01

    We reared large (1000 individuals) and small (20 individuals) populations of Tribolium castaneum on diet contaminated with copper in order to determine if the size of a population affects its ability to adapt to adverse environmental conditions. After 10 generations, we used microsatellite markers to estimate and subsequently compare the genetic variability of the copper-treated populations with that of the control populations, which were reared on uncontaminated medium. Additionally, we conducted a full cross-factorial experiment which evaluated the effects of 10 generations of "pre-exposure" to copper on a population's fitness in control and copper-contaminated environments. In order to distinguish results potentially arising from genetic adaptation from those due to non-genetic effects associated to parental exposure to copper, we subjected also F11 generation, originating from parents not exposed to copper, to the same cross-factorial experiment. The effects of long-term exposure to copper depended on population size: the growth rates of small populations that were pre-exposed to copper were inhibited compared to those of small populations reared in uncontaminated environments. Large Cu-exposed populations had a higher growth rate in the F10 generation compared to the control groups, while the growth rate of the F11 generation was unaffected by copper exposure history. The only factor that had a significant effect on genetic variability was population size, but this was to be expected given the large difference in the number of individuals between large and small populations. Neither copper contamination nor its interaction with population size affected the number of microsatellite alleles retained in the F10 generation.

  19. Decreased rate of protein synthesis, caspase-3 activity, and ubiquitin-proteasome proteolysis in soleus muscles from growing rats fed a low-protein, high-carbohydrate diet.

    PubMed

    Batistela, Emanuele; Pereira, Mayara Peron; Siqueira, Juliany Torres; Paula-Gomes, Silvia; Zanon, Neusa Maria; Oliveira, Eduardo Brandt; Navegantes, Luiz Carlos Carvalho; Kettelhut, Isis C; Andrade, Claudia Marlise Balbinotti; Kawashita, Nair Honda; Baviera, Amanda Martins

    2014-06-01

    The aim of this study was to investigate the changes in the rates of both protein synthesis and breakdown, and the activation of intracellular effectors that control these processes in soleus muscles from growing rats fed a low-protein, high-carbohydrate (LPHC) diet for 15 days. The mass and the protein content, as well as the rate of protein synthesis, were decreased in the soleus from LPHC-fed rats. The availability of amino acids was diminished, since the levels of various essential amino acids were decreased in the plasma of LPHC-fed rats. Overall rate of proteolysis was also decreased, explained by reductions in the mRNA levels of atrogin-1 and MuRF-1, ubiquitin conjugates, proteasome activity, and in the activity of caspase-3. Soleus muscles from LPHC-fed rats showed increased insulin sensitivity, with increased levels of insulin receptor and phosphorylation levels of AKT, which probably explains the inhibition of both the caspase-3 activity and the ubiquitin-proteasome system. The fall of muscle proteolysis seems to represent an adaptive response that contributes to spare proteins in a condition of diminished availability of dietary amino acids. Furthermore, the decreased rate of protein synthesis may be the driving factor to the lower muscle mass gain in growing rats fed the LPHC diet.

  20. Validation of the flooding dose technique to determine fractional rates of protein synthesis in a model bivalve species, the blue mussel (Mytilus edulis L.).

    PubMed

    McCarthy, Ian D; Nicholls, Ruth; Malham, Shelagh K; Whiteley, Nia M

    2016-01-01

    For the first time, use of the flooding dose technique using (3)H-Phenylalanine is validated for measuring whole-animal and tissue-specific rates of protein synthesis in the blue mussel Mytilus edulis (61mm shell length; 4.0g fresh body mass). Following injection, the phenylalanine-specific radioactivities in the gill, mantle and whole-animal free pools were elevated within one hour and remained elevated and stable for up to 6h following injection of (3)H-phenylalanine into the posterior adductor muscle. Incorporation of (3)H-phenylalanine into body protein was linear over time following injection and the non-significant intercepts for the regressions suggested incorporation into body protein occurred rapidly after injection. These results validate the technique for measuring rates of protein synthesis in mussels. There were no differences in the calculated rates following 1-6h incubation in gill, mantle or whole-animal and fractional rates of protein synthesis from the combined time course data were 9.5±0.8%d(-1) for the gill, 2.5±0.3%d(-1) for the mantle and 2.6±0.3%d(-1) for the whole-animal, respectively (mean values±SEM). The whole-animal absolute rate of protein synthesis was calculated as 18.9±0.6mg protein day(-1). The use of this technique in measuring one of the major components of maintenance metabolism and growth will provide a valuable and convenient tool in furthering our understanding of the protein metabolism and energetics of this keystone marine invertebrate and its ability to adjust and respond to fluctuations, such as that expected as a result of climate change.

  1. Tendon protein synthesis rate in classic Ehlers-Danlos patients can be stimulated with insulin-like growth factor-I.

    PubMed

    Nielsen, Rie Harboe; Holm, Lars; Jensen, Jacob Kildevang; Heinemeier, Katja Maria; Remvig, Lars; Kjaer, Michael

    2014-10-01

    The classic form of Ehlers-Danlos syndrome (cEDS) is an inherited connective tissue disorder, where mutations in type V collagen-encoding genes result in abnormal collagen fibrils. Thus the cEDS patients have pathological connective tissue morphology and low stiffness, but the rate of connective tissue protein turnover is unknown. We investigated whether cEDS affected the protein synthesis rate in skin and tendon, and whether this could be stimulated in tendon tissue with insulin-like growth factor-I (IGF-I). Five patients with cEDS and 10 healthy, matched controls (CTRL) were included. One patellar tendon of each participant was injected with 0.1 ml IGF-I (Increlex, Ipsen, 10 mg/ml) and the contralateral tendon with 0.1 ml isotonic saline as control. The injections were performed at both 24 and 6 h prior to tissue sampling. The fractional synthesis rate (FSR) of proteins in skin and tendon was measured with the stable isotope technique using a flood-primed continuous infusion over 6 h. After the infusion one skin biopsy and two tendon biopsies (one from each patellar tendon) were obtained. We found similar baseline FSR values in skin and tendon in the cEDS patients and controls [skin: 0.005 ± 0.002 (cEDS) and 0.007 ± 0.002 (CTRL); tendon: 0.008 ± 0.001 (cEDS) and 0.009 ± 0.002 (CTRL) %/h, mean ± SE]. IGF-I injections significantly increased FSR values in cEDS patients but not in controls (delta values: cEDS 0.007 ± 0.002, CTRL 0.001 ± 0.001%/h). In conclusion, baseline protein synthesis rates in connective tissue appeared normal in cEDS patients, and the patients responded with an increased tendon protein synthesis rate to IGF-I injections.

  2. Effect of Short-Term Mobile Phone Base Station Exposure on Cognitive Performance, Body Temperature, Heart Rate and Blood Pressure of Malaysians

    PubMed Central

    Malek, F.; Rani, K. A.; Rahim, H. A.; Omar, M. H.

    2015-01-01

    Individuals who report their sensitivity to electromagnetic fields often undergo cognitive impairments that they believe are due to the exposure of mobile phone technology. The aim of this study is to clarify whether short-term exposure at 1 V/m to the typical Global System for Mobile Communication and Universal Mobile Telecommunications System (UMTS) affects cognitive performance and physiological parameters (body temperature, blood pressure and heart rate). This study applies counterbalanced randomizing single blind tests to determine if sensitive individuals experience more negative health effects when they are exposed to base station signals compared with sham (control) individuals. The sample size is 200 subjects with 50.0% Idiopathic Environmental Intolerance attributed to electromagnetic fields (IEI-EMF) also known as sensitive and 50.0% (non-IEI-EMF). The computer-administered Cambridge Neuropsychological Test Automated Battery (CANTAB eclipseTM) is used to examine cognitive performance. Four tests are chosen to evaluate Cognitive performance in CANTAB: Reaction Time (RTI), Rapid Visual Processing (RVP), Paired Associates Learning (PAL) and Spatial Span (SSP). Paired sample t-test on the other hand, is used to examine the physiological parameters. Generally, in both groups, there is no statistical significant difference between the exposure and sham exposure towards cognitive performance and physiological effects (P’s > 0.05). PMID:26286015

  3. Effect of Short-Term Mobile Phone Base Station Exposure on Cognitive Performance, Body Temperature, Heart Rate and Blood Pressure of Malaysians.

    PubMed

    Malek, F; Rani, K A; Rahim, H A; Omar, M H

    2015-01-01

    Individuals who report their sensitivity to electromagnetic fields often undergo cognitive impairments that they believe are due to the exposure of mobile phone technology. The aim of this study is to clarify whether short-term exposure at 1 V/m to the typical Global System for Mobile Communication and Universal Mobile Telecommunications System (UMTS) affects cognitive performance and physiological parameters (body temperature, blood pressure and heart rate). This study applies counterbalanced randomizing single blind tests to determine if sensitive individuals experience more negative health effects when they are exposed to base station signals compared with sham (control) individuals. The sample size is 200 subjects with 50.0% Idiopathic Environmental Intolerance attributed to electromagnetic fields (IEI-EMF) also known as sensitive and 50.0% (non-IEI-EMF). The computer-administered Cambridge Neuropsychological Test Automated Battery (CANTAB eclipse(TM)) is used to examine cognitive performance. Four tests are chosen to evaluate Cognitive performance in CANTAB: Reaction Time (RTI), Rapid Visual Processing (RVP), Paired Associates Learning (PAL) and Spatial Span (SSP). Paired sample t-test on the other hand, is used to examine the physiological parameters. Generally, in both groups, there is no statistical significant difference between the exposure and sham exposure towards cognitive performance and physiological effects (P's > 0.05). PMID:26286015

  4. Effect of Short-Term Mobile Phone Base Station Exposure on Cognitive Performance, Body Temperature, Heart Rate and Blood Pressure of Malaysians.

    PubMed

    Malek, F; Rani, K A; Rahim, H A; Omar, M H

    2015-08-19

    Individuals who report their sensitivity to electromagnetic fields often undergo cognitive impairments that they believe are due to the exposure of mobile phone technology. The aim of this study is to clarify whether short-term exposure at 1 V/m to the typical Global System for Mobile Communication and Universal Mobile Telecommunications System (UMTS) affects cognitive performance and physiological parameters (body temperature, blood pressure and heart rate). This study applies counterbalanced randomizing single blind tests to determine if sensitive individuals experience more negative health effects when they are exposed to base station signals compared with sham (control) individuals. The sample size is 200 subjects with 50.0% Idiopathic Environmental Intolerance attributed to electromagnetic fields (IEI-EMF) also known as sensitive and 50.0% (non-IEI-EMF). The computer-administered Cambridge Neuropsychological Test Automated Battery (CANTAB eclipse(TM)) is used to examine cognitive performance. Four tests are chosen to evaluate Cognitive performance in CANTAB: Reaction Time (RTI), Rapid Visual Processing (RVP), Paired Associates Learning (PAL) and Spatial Span (SSP). Paired sample t-test on the other hand, is used to examine the physiological parameters. Generally, in both groups, there is no statistical significant difference between the exposure and sham exposure towards cognitive performance and physiological effects (P's > 0.05).

  5. [Inhibition rate of gamma-aminolevulinic acid dehydratase activity in erythrocytes as a reliable index for individual workers of low lead exposure].

    PubMed

    Hirano, H; Omichi, M; Ohishi, H; Ishikawa, K; Hirashima, N

    1983-09-01

    As the delta-aminolevulinic acid dehydratase (ALAD) activity in erythrocytes is decreased by lead exposure, we considered that a net reduction of ALAD activity by lead in blood should be the difference between the activity fully activated with zinc (Zn2+) and dithiothreitol (DTT) and that without activation. The optimal condition of activation of ALAD was found by addition of 0.25 mM of Zn2+ and 10 mM of DTT in the reaction mixture. Judging from our previous results that the amount of inhibition of ALAD activity can be represented as the rate of inhibition and is closely correlated with the dose of lead administered to rabbits, the inhibition rate of ALAD activity and lead content in blood (Pb-B) of lead workers were measured. The scatter diagram obtained from the inhibition rate and lead content in blood has two groups being divided at 50 micrograms/ml of Pb-B. In one group less than 50 micrograms/100 ml of Pb-B, the inhibition rate has been closely related to Pb-B., the regression equation being Y = 1.82 X + 11.7, and the correlation coefficient + 0.926. In another group more than 50 micrograms/100 ml of Pb-B the inhibition rate remained constant at the 90% level. Measurement of the inhibition rate suggests to have practical validity for monitoring lead exposure in workers, and by means of a nomograph lead content in blood can be estimated from the inhibition rate.

  6. Biological effects of α-radiation exposure by (241)Am in Arabidopsis thaliana seedlings are determined both by dose rate and (241)Am distribution.

    PubMed

    Biermans, Geert; Horemans, Nele; Vanhoudt, Nathalie; Vandenhove, Hildegarde; Saenen, Eline; Van Hees, May; Wannijn, Jean; Vangronsveld, Jaco; Cuypers, Ann

    2015-11-01

    Human activity has led to an increasing amount of radionuclides in the environment and subsequently to an increased risk of exposure of the biosphere to ionising radiation. Due to their high linear energy transfer, α-emitters form a threat to biota when absorbed or integrated in living tissue. Among these, (241)Am is of major concern due to high affinity for organic matter and high specific activity. This study examines the dose-dependent biological effects of α-radiation delivered by (241)Am at the morphological, physiological and molecular level in 14-day old seedlings of Arabidopsis thaliana after hydroponic exposure for 4 or 7 days. Our results show that (241)Am has high transfer to the roots but low translocation to the shoots. In the roots, we observed a transcriptional response of reactive oxygen species scavenging and DNA repair pathways. At the physiological and morphological level this resulted in a response which evolved from redox balance control and stable biomass at low dose rates to growth reduction, reduced transfer and redox balance decline at higher dose rates. This situation was also reflected in the shoots where, despite the absence of a transcriptional response, the control of photosynthesis performance and redox balance declined with increasing dose rate. The data further suggest that the effects in both organs were initiated in the roots, where the highest dose rates occurred, ultimately affecting photosynthesis performance and carbon assimilation. Though further detailed study of nutrient balance and (241)Am localisation is necessary, it is clear that radionuclide uptake and distribution is a major parameter in the global exposure effects on plant performance and health. PMID:26204519

  7. The number of genes changing expression after chronic exposure to code division multiple access or frequency DMA radiofrequency radiation does not exceed the false-positive rate.

    PubMed

    Whitehead, Timothy D; Moros, Eduardo G; Brownstein, Bernard H; Roti Roti, Joseph L

    2006-09-01

    Experiments with cultured C3H 10T 1/2 cells were performed to determine if exposure to cell phone radiofrequency (RF) radiations induce changes in gene expression. Following a 24 h exposure of 5 W/kg specific adsorption rate, RNA was extracted from the exposed and sham control cells for microarray analysis on Affymetrix U74Av2 Genechips. Cells exposed to 0.68 Gy of X-rays with a 4-h recovery were used as positive controls. The number of gene expression changes induced by RF radiation was not greater than the number of false positives expected based on a sham versus sham comparison. In contrast, the X-irradiated samples showed higher numbers of probe sets changing expression level than in the sham versus sham comparison.

  8. Fukushima simulation experiment: assessing the effects of chronic low-dose-rate internal 137Cs radiation exposure on litter size, sex ratio, and biokinetics in mice.

    PubMed

    Nakajima, Hiroo; Yamaguchi, Yoshiaki; Yoshimura, Takashi; Fukumoto, Manabu; Todo, Takeshi

    2015-12-01

    To investigate the transgenerational effects of chronic low-dose-rate internal radiation exposure after the Fukushima Daiichi Nuclear Power Plant accident in Japan, 18 generations of mice were maintained in a radioisotope facility, with free access to drinking water containing (137)CsCl (0 and 100 Bq/ml). The (137)Cs distribution in the organs of the mice was measured after long-term ad libitum intake of the (137)CsCl water. The litter size and the sex ratio of the group ingesting the (137)Cs water were compared with those of the control group, for all 18 generations of mice. No significant difference was noted in the litter size or the sex ratio between the mice in the control group and those in the group ingesting the (137)Cs water. The fixed internal exposure doses were ∼160 Bq/g and 80 Bq/g in the muscles and other organs, respectively. PMID:26825299

  9. Fukushima simulation experiment: assessing the effects of chronic low-dose-rate internal 137Cs radiation exposure on litter size, sex ratio, and biokinetics in mice

    PubMed Central

    Nakajima, Hiroo; Yamaguchi, Yoshiaki; Yoshimura, Takashi; Fukumoto, Manabu; Todo, Takeshi

    2015-01-01

    To investigate the transgenerational effects of chronic low-dose-rate internal radiation exposure after the Fukushima Daiichi Nuclear Power Plant accident in Japan, 18 generations of mice were maintained in a radioisotope facility, with free access to drinking water containing 137CsCl (0 and 100 Bq/ml). The 137Cs distribution in the organs of the mice was measured after long-term ad libitum intake of the 137CsCl water. The litter size and the sex ratio of the group ingesting the 137Cs water were compared with those of the control group, for all 18 generations of mice. No significant difference was noted in the litter size or the sex ratio between the mice in the control group and those in the group ingesting the 137Cs water. The fixed internal exposure doses were ∼160 Bq/g and 80 Bq/g in the muscles and other organs, respectively. PMID:26825299

  10. Proteome-wide muscle protein fractional synthesis rates predict muscle mass gain in response to a selective androgen receptor modulator in rats.

    PubMed

    Shankaran, Mahalakshmi; Shearer, Todd W; Stimpson, Stephen A; Turner, Scott M; King, Chelsea; Wong, Po-Yin Anne; Shen, Ying; Turnbull, Philip S; Kramer, Fritz; Clifton, Lisa; Russell, Alan; Hellerstein, Marc K; Evans, William J

    2016-03-15

    Biomarkers of muscle protein synthesis rate could provide early data demonstrating anabolic efficacy for treating muscle-wasting conditions. Androgenic therapies have been shown to increase muscle mass primarily by increasing the rate of muscle protein synthesis. We hypothesized that the synthesis rate of large numbers of individual muscle proteins could serve as early response biomarkers and potentially treatment-specific signaling for predicting the effect of anabolic treatments on muscle mass. Utilizing selective androgen receptor modulator (SARM) treatment in the ovariectomized (OVX) rat, we applied an unbiased, dynamic proteomics approach to measure the fractional synthesis rates (FSR) of 167-201 individual skeletal muscle proteins in triceps, EDL, and soleus. OVX rats treated with a SARM molecule (GSK212A at 0.1, 0.3, or 1 mg/kg) for 10 or 28 days showed significant, dose-related increases in body weight, lean body mass, and individual triceps but not EDL or soleus weights. Thirty-four out of the 94 proteins measured from the triceps of all rats exhibited a significant, dose-related increase in FSR after 10 days of SARM treatment. For several cytoplasmic proteins, including carbonic anhydrase 3, creatine kinase M-type (CK-M), pyruvate kinase, and aldolase-A, a change in 10-day FSR was strongly correlated (r(2) = 0.90-0.99) to the 28-day change in lean body mass and triceps weight gains, suggesting a noninvasive measurement of SARM effects. In summary, FSR of multiple muscle proteins measured by dynamics of moderate- to high-abundance proteins provides early biomarkers of the anabolic response of skeletal muscle to SARM. PMID:26714847

  11. Proteome-wide muscle protein fractional synthesis rates predict muscle mass gain in response to a selective androgen receptor modulator in rats.

    PubMed

    Shankaran, Mahalakshmi; Shearer, Todd W; Stimpson, Stephen A; Turner, Scott M; King, Chelsea; Wong, Po-Yin Anne; Shen, Ying; Turnbull, Philip S; Kramer, Fritz; Clifton, Lisa; Russell, Alan; Hellerstein, Marc K; Evans, William J

    2016-03-15

    Biomarkers of muscle protein synthesis rate could provide early data demonstrating anabolic efficacy for treating muscle-wasting conditions. Androgenic therapies have been shown to increase muscle mass primarily by increasing the rate of muscle protein synthesis. We hypothesized that the synthesis rate of large numbers of individual muscle proteins could serve as early response biomarkers and potentially treatment-specific signaling for predicting the effect of anabolic treatments on muscle mass. Utilizing selective androgen receptor modulator (SARM) treatment in the ovariectomized (OVX) rat, we applied an unbiased, dynamic proteomics approach to measure the fractional synthesis rates (FSR) of 167-201 individual skeletal muscle proteins in triceps, EDL, and soleus. OVX rats treated with a SARM molecule (GSK212A at 0.1, 0.3, or 1 mg/kg) for 10 or 28 days showed significant, dose-related increases in body weight, lean body mass, and individual triceps but not EDL or soleus weights. Thirty-four out of the 94 proteins measured from the triceps of all rats exhibited a significant, dose-related increase in FSR after 10 days of SARM treatment. For several cytoplasmic proteins, including carbonic anhydrase 3, creatine kinase M-type (CK-M), pyruvate kinase, and aldolase-A, a change in 10-day FSR was strongly correlated (r(2) = 0.90-0.99) to the 28-day change in lean body mass and triceps weight gains, suggesting a noninvasive measurement of SARM effects. In summary, FSR of multiple muscle proteins measured by dynamics of moderate- to high-abundance proteins provides early biomarkers of the anabolic response of skeletal muscle to SARM.

  12. Episodic ozone exposure in adult and senescent Brown Norway rats: acute and delayed effect on heart rate, core temperature and motor activity.

    PubMed

    Gordon, C J; Johnstone, A F; Aydin, C; Phillips, P M; MacPhail, R C; Kodavanti, U P; Ledbetter, A D; Jarema, K A

    2014-06-01

    Setting exposure standards for environmental pollutants may consider the aged as a susceptible population but the few published studies assessing susceptibility of the aged to air pollutants are inconsistent. Episodic ozone (O₃) is more reflective of potential exposures occurring in human populations and could be more harmful to the aged. This study used radiotelemetry to monitor heart rate (HR), core temperature (T(c)) and motor activity (MA) in adult (9-12 months) and senescent (20-24 months) male, Brown Norway rats exposed to episodic O₃ (6 h/day of 1 ppm O₃ for 2 consecutive days/week for 13 weeks). Acute O₃ initially led to marked drops in HR and T(c). As exposures progressed each week, there was diminution in the hypothermic and bradycardic effects of O₃. Senescent rats were less affected than adults. Acute responses were exacerbated on the second day of O₃ exposure with adults exhibiting greater sensitivity. During recovery following 2 d of O₃, adult and senescent rats exhibited an elevated T(c) and HR during the day but not at night, an effect that persisted for at least 48 h after O₃ exposure. MA was elevated in adults but not senescent rats during recovery from O₃. Overall, acute effects of O₃, including reductions in HR and T(c), were attenuated in senescent rats. Autonomic responses during recovery, included an elevation in T(c) with a pattern akin to that of a fever and rise in HR that were independent of age. An attenuated inflammatory response to O₃ in senescent rats may explain the relatively heightened physiological response to O₃ in younger rats. PMID:24779854

  13. Acute large-dose exposure to organophosphates in patients with and without diabetes mellitus: analysis of mortality rate and new-onset diabetes mellitus

    PubMed Central

    2014-01-01

    Background We investigated the mortality rates of patients with and without diabetes mellitus after acute large-dose exposure to organophosphate insecticides. All patients without diabetes mellitus were traced to examine the long-term risk of new-onset diabetes mellitus. Previous reports indicated that organophosphate exposure might increase the risk of new-onset diabetes mellitus. Methods We analyzed the records of 118 patients referred to Chang Gung Memorial Hospital for management of intentional organophosphate poisoning between 2000 and 2011. Patients were stratified by diabetes mellitus status. Demographic, clinical, laboratory and mortality data were analyzed. Results Most patients were middle aged (53.45 ± 16.20 years) and male (65.3%) and were referred to our hospital after a relatively short amount of time had elapsed since poisoning (median 3.0 hours). 18 (15.2%) of 118 patients died, including 15 (13.8%) of 109 patients without diabetes mellitus and 3 (33.3%) of 9 with diabetes mellitus. There was no significant difference in mortality between these groups (P = 0.117). In a multivariate Cox regression model, hypotension (P = 0.000), respiratory failure (P = 0.042), coma (P = 0.023), and corrected QT interval prolongation (P = 0.002) were significant risk factors for mortality. Conversely, diabetes mellitus status was not a significant variable in this model. At routine outpatient follow up a median of 1.25 months post exposure, random blood glucose measurements gave no evidence of new-onset diabetes in patients without pre-existing diabetes. Conclusions Diabetes mellitus status might not increase mortality risk following acute large-dose exposure to organophosphates, and the risk of new-onset diabetes mellitus also might be minimal in the short term. Larger prospective studies with formal testing for diabetes at later times post-exposure are required. PMID:24597539

  14. An exposure based study of crash and injury rates in a cohort of transport and recreational cyclists in New South Wales, Australia.

    PubMed

    Poulos, R G; Hatfield, J; Rissel, C; Flack, L K; Murphy, S; Grzebieta, R; McIntosh, A S

    2015-05-01

    This paper examines self-reported prospectively collected data from 2038 adult transport and recreational cyclists from New South Wales (Australia) to determine exposure-based incident crash and injury rates. During 25,971 days of cycling, 198 crashes were reported, comprising approximately equal numbers of falls and collisions. The overall crash rate was 0.290 (95% CI, 0.264-0.319) per 1000km or 6.06 (95% CI, 5.52-6.65) per 1000h of travel. The rate of crashes causing any injury (self-treated, or medically attended without overnight hospital stay) was 0.148 (95% CI, 0.133-0.164) per 1000km or 3.09 (95% CI, 2.79-3.43) per 1000h of travel. The rate of crashes causing a medically attended injury (without overnight hospital stay) was 0.023 (95% CI, 0.020-0.027) per 1000km or 0.49 (95% CI, 0.43-0.56) per 1000h of travel. No injuries requiring an overnight stay in hospital were reported on days meeting the inclusion criteria. After adjustment for exposure in hours, or for the risks associated with different infrastructure utilisation, the rates of crashes and medically attended injuries were found to be greater for females than males, less experienced than more experienced cyclists, and for those who rode mainly for transport rather than mainly for recreation. Comparison of estimated crash and injury rates on different infrastructure types were limited by the small number of events, however findings suggest that the separation of cyclists from motorised traffic is by itself not sufficient to ensure safe cycling.

  15. UV-induced unscheduled DNA synthesis in human skin: dose response, correlation with erythema, time course and split dose exposure in vivo.

    PubMed

    Hönigsmann, H; Brenner, W; Tanew, A; Ortel, B

    1987-09-01

    Unscheduled DNA synthesis (UDS) has been shown to be saturated above a threshold dose of UV-C in human fibroblasts in vitro. We have investigated by autoradiography whether a similar saturation occurs in human skin in vivo with UV-B and whether this phenomenon correlates with the erythemal response. In addition, we determined the time course of UDS at 24 h after exposure and the effect of dual exposures separated by 24 h. The dose-response curve was established by exposure to 1/16, 1/8, 1/4, 1/2, 1, 2, 3, 4 and 6 MEDs UV-B. For the time-course study, areas exposed to 1/2 and 2 MEDs were biopsied after 1, 3, 6, 12 and 24 h. Autoradiography was performed in vitro. The dose-response curve showed a significant increase in UDS from 1/16 to 1 minimal erythema dose (MED), whereas no significant difference was observed between 1 MED and the higher UV-B doses tested. The 24 h time sequence revealed a gradual decrease in UDS activity. The 1/2 MED curve declined more rapidly and reached the zero-level between 12 h and 24 h, whereas about 50% of the initial UDS value was still retained 24 h after 2 MEDs. The dual-dose study revealed that a second hit of fractions of the MED resulted in lower levels of UDS than induced by these fractions alone in previously untreated areas. UDS increases with the erythemal dose between 1/16 and 1 MED. It reaches a plateau after 1 MED and cannot be increased by doses up to 6 MEDs, suggesting a saturation of excision repair in vivo. Time course studies support such a saturation phenomenon. The failure to increase significantly UDS by a second irradiation 24 h after the first exposure needs further clarification. Since persistence of DNA lesions may lead to an accumulation after repeated exposures, additional mechanisms other than excision repair may protect human skin by error-free removal of possibly mutagenic sites. Photoreactivation may be important in this respect.

  16. Rate of exposure of a sentinel species, invasive American mink (Neovison vison) in Scotland, to anticoagulant rodenticides.

    PubMed

    Ruiz-Suárez, Norberto; Melero, Yolanda; Giela, Anna; Henríquez-Hernández, Luis A; Sharp, Elizabeth; Boada, Luis D; Taylor, Michael J; Camacho, María; Lambin, Xavier; Luzardo, Octavio P; Hartley, Gill

    2016-11-01

    Anticoagulant rodenticides (ARs) are highly toxic compounds that are exclusively used for the control of rodent pests. Despite their defined use, they are nonetheless found in a large number of non-target species indicating widespread penetration of wildlife. Attempts to quantify the scale of problem are complicated by non-random sampling of individuals tested for AR contamination. The American mink (Neovison vison) is a wide ranging, non-native, generalist predator that is subject to wide scale control efforts in the UK. Exposure to eight ARs was determined in 99 mink trapped in NE Scotland, most of which were of known age. A high percentage (79%) of the animals had detectable residues of at least one AR, and more than 50% of the positive animals had two or more ARs. The most frequently detected compound was bromadiolone (75% of all animals tested), followed by difenacoum (53% of all mink), coumatetralyl (22%) and brodifacoum (9%). The probability of mink exposure to ARs increased by 4.5% per month of life, and was 1.7 times higher for mink caught in areas with a high, as opposed to a low, density of farms. The number of AR compounds acquired also increased with age and with farm density. No evidence was found for sexual differences in the concentration and number of ARs. The wide niche and dietary overlap of mink with several native carnivore species, and the fact that American mink are culled for conservation throughout Europe, suggest that this species may act as a sentinel species, and the application of these data to other native carnivores is discussed.

  17. Rate of exposure of a sentinel species, invasive American mink (Neovison vison) in Scotland, to anticoagulant rodenticides.

    PubMed

    Ruiz-Suárez, Norberto; Melero, Yolanda; Giela, Anna; Henríquez-Hernández, Luis A; Sharp, Elizabeth; Boada, Luis D; Taylor, Michael J; Camacho, María; Lambin, Xavier; Luzardo, Octavio P; Hartley, Gill

    2016-11-01

    Anticoagulant rodenticides (ARs) are highly toxic compounds that are exclusively used for the control of rodent pests. Despite their defined use, they are nonetheless found in a large number of non-target species indicating widespread penetration of wildlife. Attempts to quantify the scale of problem are complicated by non-random sampling of individuals tested for AR contamination. The American mink (Neovison vison) is a wide ranging, non-native, generalist predator that is subject to wide scale control efforts in the UK. Exposure to eight ARs was determined in 99 mink trapped in NE Scotland, most of which were of known age. A high percentage (79%) of the animals had detectable residues of at least one AR, and more than 50% of the positive animals had two or more ARs. The most frequently detected compound was bromadiolone (75% of all animals tested), followed by difenacoum (53% of all mink), coumatetralyl (22%) and brodifacoum (9%). The probability of mink exposure to ARs increased by 4.5% per month of life, and was 1.7 times higher for mink caught in areas with a high, as opposed to a low, density of farms. The number of AR compounds acquired also increased with age and with farm density. No evidence was found for sexual differences in the concentration and number of ARs. The wide niche and dietary overlap of mink with several native carnivore species, and the fact that American mink are culled for conservation throughout Europe, suggest that this species may act as a sentinel species, and the application of these data to other native carnivores is discussed. PMID:27387798

  18. Plutonium aerosol fluxes and pulmonary exposure rates during resuspension from bare soils near a chemical separation facility

    SciTech Connect

    Shinn, J.H.; Homan, D.N.; Gay, D.D.

    1982-11-01

    The purpose of this study was to examine the plutonium aerosol fluxes (Curies per ground area per unit time) from a bare soil near a chemical separation facility and to determine the characteristics of the plutonium-bearing aerosols, which are of consequence in deposition of the alpha-emitters into the lung. These characteristics are the plutonium aerosol concentration (Curies per unit volume of air), the particle size distribution, the radioactivity size distribution, the enhancement factors, and others. The site was the agricultural field adjacent to H-area of Savannah River Plant near Aiken, South Carolina, where low-level releases of /sup 239/Pu and /sup 240/Pu occurred from 1967 through 1974. The releases then changed primarily to /sup 238/Pu. Results indicate that plutonium aerosol concentrations were not greatly increased by removing the vegetation and cultivating the field. Following a rain which stabilized the surface /sup 239/Pu concentrations were 37% of normal to 144% of normal as the field dried. The /sup 239/Pu concentration was broadly distributed over particle sizes and had MAD 2.7 ..mu..m. The /sup 239/Pu concentration distributions were found to be 12% respirable and the maximum concentration observed, 4.94 x 10/sup -17/ Ci m/sup -3/, amounted to an inconsequential exposure of less than 10/sup -5/ lifetime background dose for 100 days exposure. /sup 239/Pu flux was not greatly increased as the dust flux increased because /sup 239/Pu activity of the aerosols decreased with time to counteract the increased dust flux.

  19. The role of dose rate in radiation cancer risk: evaluating the effect of dose rate at the molecular, cellular and tissue levels using key events in critical pathways following exposure to low LET radiation

    PubMed Central

    Brooks, Antone L.; Hoel, David G.; Preston, R. Julian

    2016-01-01

    Abstract Purpose: This review evaluates the role of dose rate on cell and molecular responses. It focuses on the influence of dose rate on key events in critical pathways in the development of cancer. This approach is similar to that used by the U.S. EPA and others to evaluate risk from chemicals. It provides a mechanistic method to account for the influence of the dose rate from low-LET radiation, especially in the low-dose region on cancer risk assessment. Molecular, cellular, and tissues changes are observed in many key events and change as a function of dose rate. The magnitude and direction of change can be used to help establish an appropriate dose rate effectiveness factor (DREF). Conclusions: Extensive data on key events suggest that exposure to low dose-rates are less effective in producing changes than high dose rates. Most of these data at the molecular and cellular level support a large (2–30) DREF. In addition, some evidence suggests that doses delivered at a low dose rate decrease damage to levels below that observed in the controls. However, there are some data human and mechanistic data that support a dose-rate effectiveness factor of 1. In summary, a review of the available molecular, cellular and tissue data indicates that not only is dose rate an important variable in understanding radiation risk but it also supports the selection of a DREF greater than one as currently recommended by ICRP (2007) and BEIR VII (NRC/NAS 2006). PMID:27266588

  20. Microbial Transformation of Triadimefon to Triadimenol in Soils: Selective Production Rates of Triadimenol Stereoisomers Affect Exposure and Risk

    EPA Science Inventory

    The microbial transformation of triadimefon, an agricultural fungicide of the 1,2,4-triazole class, was followed at a nominal concentration of 50 μg/mL over 4 months under aerobic conditions in three different soil types. Rates and products of transformation were measured, as wel...

  1. Exposure to elevated temperature and Pco(2) reduces respiration rate and energy status in the periwinkle Littorina littorea.

    PubMed

    Melatunan, Sedercor; Calosi, Piero; Rundle, Simon D; Moody, A John; Widdicombe, Stephen

    2011-01-01

    In the future, marine organisms will face the challenge of coping with multiple environmental changes associated with increased levels of atmospheric Pco(2), such as ocean warming and acidification. To predict how organisms may or may not meet these challenges, an in-depth understanding of the physiological and biochemical mechanisms underpinning organismal responses to climate change is needed. Here, we investigate the effects of elevated Pco(2) and temperature on the whole-organism and cellular physiology of the periwinkle Littorina littorea. Metabolic rates (measured as respiration rates), adenylate energy nucleotide concentrations and indexes, and end-product metabolite concentrations were measured. Compared with values for control conditions, snails decreased their respiration rate by 31% in response to elevated Pco(2) and by 15% in response to a combination of increased Pco(2) and temperature. Decreased respiration rates were associated with metabolic reduction and an increase in end-product metabolites in acidified treatments, indicating an increased reliance on anaerobic metabolism. There was also an interactive effect of elevated Pco(2) and temperature on total adenylate nucleotides, which was apparently compensated for by the maintenance of adenylate energy charge via AMP deaminase activity. Our findings suggest that marine intertidal organisms are likely to exhibit complex physiological responses to future environmental drivers, with likely negative effects on growth, population dynamics, and, ultimately, ecosystem processes. PMID:22030851

  2. Visualisation of brain tumors and quantitation of the protein synthesis rate with L-1-[C-11]-tyrosine

    SciTech Connect

    Pruim, J.; Willemsen, A.T.M.; Waarde, A. van

    1994-05-01

    We have developed the tracer L-1-[C-11]-tyrosine (TYR) for the quantitation of the protein synthesis rate (PSR) in tumours. Here the first results with TYR in a group of patients with (suspected) primary or recurrent brain tumours are reported. Twenty-six patients were studied: 12 male, 14 female, age 45{plus_minus}16 (mean{plus_minus}S.D.) years. At the time of the study the diagnosis of a primary tumour or recurrent tumour was considered on the basis of clinical symptoms and CT/MRI. Patients received 237{plus_minus}111 MBq TYR i.v. Seventeen patients were studied in a dynamic mode (frame sequence: 10 x 0.5, 3 x 5, 3 x 10 minutes). During the studies, arterial blood samples were taken for measurement of the input function, and the assessment of metabolites ([C-11]CO{sub 2}, [C-11]proteins). ROIs were placed over the tumour and using a modified Patlak-analysis the PSR was calculated. In the other 9 patients a static emission scan was made, 20-40 min after injection. All images were corrected for attenuation via a transmission scan. Histology or cytology of the tumour was obtained shortly after the TYR-PET in 20 patients. The calculated PSR of the tumours was 1.0{plus_minus}0.6 nmol/ml/min. This is in range with our animal experiments. The PSR in brain tissue of the contralateral hemisphere was 0.7{plus_minus}0.4 nmol/ml/min. Sixteen of the turnouts were correctly identified with TYR-PET. Also, 2 benign lesions were correctly identified. TYR-PET gave 1 false-positive (infarction) and 1 false-negative (astrocytoma of intermediate malignancy) result. In a few patients with extensive peri-tumoural edema on MRI/CT, additional tumour locations were found with TYR-PET, proven to be malignant on biopsy. In conclusion: TYR is applicable for the visualisation of brain tumours. The possibility of calculating a PSR allows its use in the evaluation of therapy.

  3. Effect of indoor air pollution during cooking on peak expiratory flow rate and its association with exposure index in rural women.

    PubMed

    Sukhsohale, Neelam D; Narlawar, Uday W; Phatak, Mrunal S; Agrawal, Sanjay B; Ughade, Suresh N

    2013-01-01

    Routine exposure to domestic cooking fuels is an important source of indoor air pollution causing deterioration of lung function. We conducted a community based cross-sectional study in 760 non-smoking rural women involved in household cooking with four types of cooking fuels i.e. Biomass, Kerosene stove, Liquid Petroleum Gas (LPG) and Mixed (combination of two and more cooking fuels). Peak Expiratory Flow Rate (PEFR) less than 80% of the predicted was considered as abnormal PEFR. The overall prevalence of abnormal PEFR was found to be 29.1% with greater predominance among biomass fuel users (43.3%) with high risk ratio (1.86) as compared to kerosene (0.63), LPG (0.75) and mixed (0.66) fuel users. However the pair wise comparison of different groups of cooking fuels by Marascuilo procedure reported significant differences within different groups except kerosene--mixed group. The study also demonstrated a negative correlation between observed PEFR and exposure indices in different cooking fuels (r = -0.51). Our results indicate that prolonged exposure to cooking fuels particularly biomass fuels as a source of cooking adversely affects PEFR in nonsmoking rural women.

  4. Modeling spatial and temporal variability of residential air exchange rates for the Near-Road Exposures and Effects of Urban Air Pollutants Study (NEXUS).

    PubMed

    Breen, Michael S; Burke, Janet M; Batterman, Stuart A; Vette, Alan F; Godwin, Christopher; Croghan, Carry W; Schultz, Bradley D; Long, Thomas C

    2014-11-07

    Air pollution health studies often use outdoor concentrations as exposure surrogates. Failure to account for variability of residential infiltration of outdoor pollutants can induce exposure errors and lead to bias and incorrect confidence intervals in health effect estimates. The residential air exchange rate (AER), which is the rate of exchange of indoor air with outdoor air, is an important determinant for house-to-house (spatial) and temporal variations of air pollution infiltration. Our goal was to evaluate and apply mechanistic models to predict AERs for 213 homes in the Near-Road Exposures and Effects of Urban Air Pollutants Study (NEXUS), a cohort study of traffic-related air pollution exposures and respiratory effects in asthmatic children living near major roads in Detroit, Michigan. We used a previously developed model (LBL), which predicts AER from meteorology and questionnaire data on building characteristics related to air leakage, and an extended version of this model (LBLX) that includes natural ventilation from open windows. As a critical and novel aspect of our AER modeling approach, we performed a cross validation, which included both parameter estimation (i.e., model calibration) and model evaluation, based on daily AER measurements from a subset of 24 study homes on five consecutive days during two seasons. The measured AER varied between 0.09 and 3.48 h(-1) with a median of 0.64 h(-1). For the individual model-predicted and measured AER, the median absolute difference was 29% (0.19 h‑1) for both the LBL and LBLX models. The LBL and LBLX models predicted 59% and 61% of the variance in the AER, respectively. Daily AER predictions for all 213 homes during the three year study (2010-2012) showed considerable house-to-house variations from building leakage differences, and temporal variations from outdoor temperature and wind speed fluctuations. Using this novel approach, NEXUS will be one of the first epidemiology studies to apply calibrated and

  5. The Role of Age and Exposure to Plasmodium falciparum in the Rate of Acquisition of Naturally Acquired Immunity: A Randomized Controlled Trial

    PubMed Central

    Guinovart, Caterina; Dobaño, Carlota; Bassat, Quique; Nhabomba, Augusto; Quintó, Llorenç; Manaca, Maria Nélia; Aguilar, Ruth; Rodríguez, Mauricio H.; Barbosa, Arnoldo; Aponte, John J.; Mayor, Alfredo G.; Renom, Montse; Moraleda, Cinta; Roberts, David J.; Schwarzer, Evelin; Le Souëf, Peter N.; Schofield, Louis; Chitnis, Chetan E.; Doolan, Denise L.; Alonso, Pedro L.

    2012-01-01

    Background The rate of acquisition of naturally acquired immunity (NAI) against malaria predominantly depends on transmission intensity and age, although disentangling the effects of these is difficult. We used chemoprophylaxis to selectively control exposure to P. falciparum during different periods in infancy and explore the effect of age in the build-up of NAI, measured as risk of clinical malaria. Methods and Findings A three-arm double-blind randomized placebo-controlled trial was conducted in 349 infants born to Mozambican HIV-negative women. The late exposure group (LEG) received monthly Sulfadoxine-Pyrimethamine (SP) plus Artesunate (AS) from 2.5–4.5 months of age and monthly placebo from 5.5–9.5 months; the early exposure group (EEG) received placebo from 2.5–4.5 months and SP+AS from 5.5–9.5 months; and the control group (CG) received placebo from 2.5–9.5 months. Active and passive case detection (PCD) were conducted from birth to 10.5 and 24 months respectively. The primary endpoint was time to first or only episode of malaria in the second year detected by PCD. The incidence of malaria during the second year was of 0.50, 0.51 and 0.35 episodes/PYAR in the LEG, EEG and CG respectively (p = 0.379 for the adjusted comparison of the 3 groups). The hazard ratio of the adjusted comparison between the LEG and the CG was 1.38 (0.83–2.28, p = 0.642) and that between the EEG and the CG was 1.35 (0.81–2.24, p = 0.743). Conclusions After considerably interfering with exposure during the first year of life, there was a trend towards a higher risk of malaria in the second year in children who had received chemoprophylaxis, but there was no significant rebound. No evidence was found that the age of first exposure to malaria affects the rate of acquisition of NAI. Thus, the timing of administration of antimalarial interventions like malaria vaccines during infancy does not appear to be a critical determinant. Trial Registration Clinical

  6. Effects of progestagen exposure duration on estrus synchronization and conception rates of crossbreed ewes undergoing fixed time artificial insemination.

    PubMed

    Blaschi, Wanessa; Lunardelli, Paula A; Marinho, Luciana S R; Max, Marilu C; Santos, Gustavo M G; Silva-Santos, Katia C; Melo-Sterza, Fabiana A; Baldassarre, Hernan; Rigo, Thales R; Seneda, Marcelo M

    2014-01-01

    Synchronization of estrus and ovulation are of paramount importance in modern livestock improvement programs. These methods are critical for assisted reproduction technologies, including artificial insemination and embryo transfer, that can increase productivity. In the current study, subcutaneous implants containing norgestomet were placed for long (14 days), medium (9 days), and short (5 days) periods of time in 70 crossbred ewes undergoing fixed-time artificial insemination. The resulting effects on estrus synchronization and conception rates were subsequently evaluated. Among the synchronized ewes, 85.7% (60/70) underwent estrus over a period of 72 h after progestagen treatment ceased. The shortest mean interval between withdrawal of the device and onset of estrus (34.2 ± 8.9 h) was observed in the G14 days of P4 group (p < 0.05). The conception rate of the G14 days of P4 group was statistically higher than that of the other groups (83.3% vs. 60.9% vs. 47.8%; p < 0.05). In conclusion, 14 days of norgestomet treatment produced higher conception rates and a greater number of pregnancies at the beginning of the breeding season.

  7. Influence of inocula with prior hydrocarbon exposure on biodegradation rates of diesel, synthetic diesel, and fish-biodiesel in soil.

    PubMed

    Horel, Agota; Schiewer, Silke

    2014-08-01

    To achieve effective bioremediation within short warm seasons of cold climates, microbial adaptation periods to the contaminant should be brief. The current study investigated growth phases for soil spiked with diesel, Syntroleum, or fish biodiesel, using microbial inocula adapted to the specific substrates. For modeling hydrocarbon degradation, multi-phase first order kinetics was assumed, comparing linear regression with nonlinear parameter optimization of rate constants and phase durations. Lag phase periods of 5 to >28d were followed by short and intense exponential growth phases with high rate constants (e.g. from kFish=0.0013±0.0002 to kSyntr=0.015±0.001d(-1)). Hydrocarbon mineralization was highest for Syntroleum contamination, where up to three times higher cumulative CO2 production was achieved than for diesel fuel, with fish biodiesel showing initially the slowest degradation. The amount of hydrocarbons recovered from the soil by GC-MS decreased in the order fish biodiesel>diesel>Syntroleum. During initial weeks, biodegradation was higher for microbial inocula adapted to a specific fuel type, whereby the main effect of the inoculum was to shorten the lag phase duration; however, the inoculum's importance diminished after daily respiration peaked. In conclusion, addition of an inoculum to increase biodegradation rates was not necessary.

  8. Rates of mutant structural chromosome rearrangements in human fetuses: data from prenatal cytogenetic studies and associations with maternal age and parental mutagen exposure.

    PubMed Central

    Hook, E B; Schreinemachers, D M; Willey, A M; Cross, P K

    1983-01-01

    In 27,225 prenatal cytogenetic studies of amniotic fluid reported to the New York State Chromosome Registry and the United States Interregional Chromosome Register System, there were 61 cases with a structural chromosomal abnormality not known inherited, a rate per 1,000 of 2.24. Of these 33, 1.21 per 1,000 were known de novo and nonmosaic; consequently, the rate of events resulting from germinal mutation is highly likely to be between these two limits. The rates per 1,000 of unbalanced abnormalities were 0.59-1.29; of balanced abnormalities, 0.62-0.96; of balanced Robertsonian translocations, 0.22-0.29; and of unbalanced Robertsonian translocations, 0.07-0.11. The rates of fetuses with supernumerary markers and fragments were unexpectedly high: 0.26-0.70 per 1,000. These abnormalities were associated with increased maternal age (38.0 +/- 5.4 to 38.4 +/- 3.6 compared to 35.6 +/- 4.3 in controls), but even after adjustment for the bias to preferential study of older women, the observed rates of these supernumerary abnormalities were greater than would be expected from live-birth studies or rates estimated in all recognized conceptuses. There were trends to elevated maternal age for the group of all balanced rearrangements, and to diminished maternal age for the nonsupernumerary, non-Robertsonian unbalanced rearrangements. In 136 women studied primarily because of exposure to a putative mutagen, a de novo deletion and an inversion not known inherited were detected. The rate of abnormality in these 136, 1.47%, was significantly greater than the rate of abnormality in the remainder: 0.14%-0.22%. PMID:6823977

  9. Reduction of exposure to ultrafine particles by kitchen exhaust hoods: the effects of exhaust flow rates, particle size, and burner position.

    PubMed

    Rim, Donghyun; Wallace, Lance; Nabinger, Steven; Persily, Andrew

    2012-08-15

    Cooking stoves, both gas and electric, are one of the strongest and most common sources of ultrafine particles (UFP) in homes. UFP have been shown to be associated with adverse health effects such as DNA damage and respiratory and cardiovascular diseases. This study investigates the effectiveness of kitchen exhaust hoods in reducing indoor levels of UFP emitted from a gas stove and oven. Measurements in an unoccupied manufactured house monitored size-resolved UFP (2 nm to 100 nm) concentrations from the gas stove and oven while varying range hood flow rate and burner position. The air change rate in the building was measured continuously based on the decay of a tracer gas (sulfur hexafluoride, SF(6)). The results show that range hood flow rate and burner position (front vs. rear) can have strong effects on the reduction of indoor levels of UFP released from the stove and oven, subsequently reducing occupant exposure to UFP. Higher range hood flow rates are generally more effective for UFP reduction, though the reduction varies with particle diameter. The influence of the range hood exhaust is larger for the back burner than for the front burner. The number-weighted particle reductions for range hood flow rates varying between 100 m(3)/h and 680 m(3)/h range from 31% to 94% for the front burner, from 54% to 98% for the back burner, and from 39% to 96% for the oven.

  10. Hearing threshold and heart rate in men after repeated exposure to dynamic muscle work, sinusoidal vs stochastic whole body vibration and stable broadband noise.

    PubMed

    Manninen, O

    1984-01-01

    Changes in the temporary hearing threshold ( TTS2 ) and heart rate (HR) were examined in subjects exposed to stable noise, whole body vibration and dynamic muscular work at a dry-bulb temperature of 30 degrees C. The exposure combinations consisted of three categories of dynamic muscular work with varying loads ( 2W , 4W , 8W ), of two categories of noise and of three categories of vibration. The noise categories were: (1) no noise, and (2) stable, broadband (bandwidth 0.2-16.0 kHz) A-weighted noise with an intensity of 90 dB. The vibration categories were: (1) no vibration, (2) sinusoidal whole body vibration (Z-axis) with a frequency of 5 Hz, and (3) stochastic broadband (bandwidth 2.8-11.2 Hz) whole body vibration. A single test consisted of a control period of 30 min, three consecutive exposure periods of 16 min, each followed by a 4-min post-exposure interval and a recovery period of 15 min. The results of the variance analyses indicated that noise had the most notable effect on the TTS2 values at the hearing frequencies of both 4 and 6 kHz. Of the paired combinations, noise plus vibration and noise plus dynamic muscular work caused the most obvious combined effects. The combined effect of all three factors (noise, vibration and work) on the TTS2 values after three consecutive exposure periods was significant at the 2.5% level at the 4 kHz hearing frequency and at the 5% level at the 6 kHz hearing frequency. The added effect of vibration on enhanced TTS2 values was particularly clear when the vibration was stochastic and when the subjects had a low ( 2W ) working efficiency. Increasing the working efficiency, on the other hand, seemed to retard increases in the hearing threshold. Thus TTS2 values seemed to reflect the changes in HR values. It is as if the low rate of cardiovascular activity during light dynamic muscular work had enabled the manifestation of the cardiovascular effects of noise and vibration; during strenuous dynamic muscular work, however, the

  11. Arginine depletion by arginine deiminase does not affect whole protein metabolism or muscle fractional protein synthesis rate in mice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Due to the absolute need for arginine that certain cancer cells have, arginine depletion is a therapy in clinical trials to treat several types of cancers. Arginine is an amino acids utilized not only as a precursor for other important molecules, but also for protein synthesis. Because arginine depl...

  12. Comparison of 12-Year-Old Children with Prenatal Exposure to Cocaine and Non-Exposed Controls on Caregiver Ratings of Executive Function

    PubMed Central

    Minnes, Sonia; Singer, Lynn; Min, Meeyoung O.; Lang, Adelaide M.; Ben-Harush, Aya; Short, Elizabeth; Wu, Miaoping

    2013-01-01

    Differences in caregiver reported executive function in 12-year-old children who were prenatally exposed to cocaine (PCE) compared to children who were not prenatally exposed to cocaine (NCE) were assessed. One hundred and sixty-nine PCE and 169 NCE, primarily African-American, low socioeconomic status children participated in a prospective longitudinal study. The Behavior Rating Inventory of Executive Function (BRIEF) Parent Form was administered. Two broadband BRIEF scores (Behavioral Regulation Index (BRI) and Metacognition Index (MI)) and a summary Global Executive Composite (GEC) were computed. Multiple and logistic regression analyses were used to assess the effects of amount of PCE on executive function, controlling for covariates including caregiver (rater) psychological distress, child’s gender and other prenatal drug exposure variables. After adjustment for covariates, amount of PCE was associated with the GEC and two MI subscales, Plan/Organize and Monitor, with heavier exposure associated with more problems of executive function. An amount of PCE by gender interaction revealed amount of PCE effects in other remaining subscales of the MI (Initiate, Working Memory, and Organization of Materials) only among girls. Head circumference did not mediate the effects of cocaine on outcomes. Higher current caregiver psychological distress levels were independently associated with poorer ratings on the executive function scales. Assessment and targeted interventions to improve metacognitive processes are recommended for girls who were prenatally exposed to cocaine. PMID:23423839

  13. Comparison of 12-year-old children with prenatal exposure to cocaine and non-exposed controls on caregiver ratings of executive function.

    PubMed

    Minnes, Sonia; Singer, Lynn T; Min, Meeyoung O; Lang, Adelaide M; Ben-Harush, Aya; Short, Elizabeth; Wu, Miaoping

    2014-01-01

    Differences in caregiver reported executive function in 12-year-old children who were prenatally exposed to cocaine (PCE) compared to children who were not prenatally exposed to cocaine (NCE) were assessed. One hundred and sixty-nine PCE and 169 NCE, primarily African-American, low socioeconomic status children participated in a prospective longitudinal study. The Behavior Rating Inventory of Executive Function (BRIEF) Parent Form was administered. Two broadband BRIEF scores (Behavioral Regulation Index (BRI) and Metacognition Index (MI)) and a summary Global Executive Composite (GEC) were computed. Multiple and logistic regression analyses were used to assess the effects of amount of PCE on executive function, controlling for covariates including caregiver (rater) psychological distress, child's gender and other prenatal drug exposure variables. After adjustment for covariates, amount of PCE was associated with the GEC and two MI subscales, Plan/Organize and Monitor, with heavier exposure associated with more problems of executive function. An amount of PCE by gender interaction revealed amount of PCE effects in other remaining subscales of the MI (Initiate, Working Memory, and Organization of Materials) only among girls. Head circumference did not mediate the effects of cocaine on outcomes. Higher current caregiver psychological distress levels were independently associated with poorer ratings on the executive function scales. Assessment and targeted interventions to improve metacognitive processes are recommended for girls who were prenatally exposed to cocaine.

  14. Influence of the Sampling Rate and Noise Characteristics on Prediction of the Maximal Safe Laser Exposure in Human Skin Using Pulsed Photothermal Radiometry

    NASA Astrophysics Data System (ADS)

    Vidovič, L.; Milanič, M.; Majaron, B.

    2013-09-01

    Pulsed photothermal radiometry (PPTR) allows for noninvasive determination of the laser-induced temperature depth profile in strongly scattering samples, including human skin. In a recent experimental study, we have demonstrated that such information can be used to derive rather accurate predictions of the maximal safe radiant exposure on an individual patient basis. This has important implications for efficacy and safety of several laser applications in dermatology and aesthetic surgery, which are often compromised by risk of adverse side effects (e.g., scarring, and dyspigmentation) resulting from nonselective absorption of strong laser light in epidermal melanin. In this study, the differences between the individual maximal safe radiant exposure values as predicted from PPTR temperature depth profiling performed using a commercial mid-IR thermal camera (as used to acquire the original patient data) and our customized PPTR setup are analyzed. To this end, the latter has been used to acquire 17 PPTR records from three healthy volunteers, using 1 ms laser irradiation at 532 nm and a signal sampling rate of 20 000 . The laser-induced temperature profiles are reconstructed first from the intact PPTR signals, and then by binning the data to imitate the lower sampling rate of the IR camera (1000 fps). Using either the initial temperature profile in a dedicated numerical model of heat transfer or protein denaturation dynamics, the predicted levels of epidermal thermal damage and the corresponding are compared. A similar analysis is performed also with regard to the differences between noise characteristics of the two PPTR setups.

  15. The relationship of temperature rise to specific absorption rate and current in the human leg for exposure to electromagnetic radiation in the high frequency band.

    PubMed

    Wainwright, P R

    2003-10-01

    Of the biological effects of human exposure to radiofrequency and microwave radiation, the best-established are those due to elevation of tissue temperature. To prevent harmful levels of heating, restrictions have been proposed on the specific absorption rate (SAR). However, the relationship between SAR and temperature rise is not an invariant, since not only the heat capacity but also the efficiency of heat dissipation varies between different tissues and exposure scenarios. For small enough SAR, the relationship is linear and may be characterized by a 'heating factor' deltaT/SAR. Under whole-body irradiation the SAR may be particularly high in the ankles due to the concentration of current flowing through a relatively small cross-sectional area. In a previous paper, the author has presented calculations of the SAR distribution in a human leg in the high frequency (HF) band. In this paper, the heating factor for this situation is derived using a finite element approximation of the Pennes bioheat equation. The sensitivity of the results to different blood perfusion rates is investigated, and a simple local thermoregulatory model is applied. Both time-dependent and steady-state solutions are considered. Results confirm the appropriateness of the ICNIRP reference level of 100 mA on current through the leg, but suggest that at higher currents significant thermoregulatory adjustments to muscle blood flow will occur.

  16. Accelerated Growth Rate Induced by Neonatal High-Protein Milk Formula Is Not Supported by Increased Tissue Protein Synthesis in Low-Birth-Weight Piglets

    PubMed Central

    Jamin, Agnès; Sève, Bernard; Thibault, Jean-Noël; Floc'h, Nathalie

    2012-01-01

    Low-birth-weight neonates are routinely fed a high-protein formula to promote catch-up growth and antibiotics are usually associated to prevent infection. Yet the effects of such practices on tissue protein metabolism are unknown. Baby pigs were fed from age 2 to 7 or 28 d with high protein formula with or without amoxicillin supplementation, in parallel with normal protein formula, to determine tissue protein metabolism modifications. Feeding high protein formula increased growth rate between 2 and 28 days of age when antibiotic was administered early in the first week of life. This could be explained by the occurrence of diarrhea when piglets were fed the high protein formula alone. Higher growth rate was associated with higher feed conversion and reduced protein synthesis rate in the small intestine, muscle and carcass, whereas proteolytic enzyme activities measured in these tissues were unchanged. In conclusion, accelerated growth rate caused by high protein formula and antibiotics was not supported by increased protein synthesis in muscle and carcass. PMID:22315674

  17. A cis-active regulatory gene in the mouse: direct demonstration of cis-active control of the rate of enzyme subunit synthesis

    SciTech Connect

    Bernstine, E.G.; Koh, C.

    1980-07-01

    Mouse mitochondrial malic enzyme (L-malate:NADP/sup +/ oxidoreductase (oxaloacetate-decarboxylating), EC1.1.1.40) is a tetrameric protein. Two alleles of the structural gene (Mod-2) are known which code for electrophoretically distinct enzyme subunits: Mod-2/sup a/ and Mod-2/sup b/. A regulatory gene (Mdr-1), closely linked to Mod-2 on chromosome 7, determines the rate of mitochondrial malic enzyme synthesis in brain. Two alleles of Mdr-1 are known: Mdr-1/sup a/ (high activity) and Mdr-1/sup b/ (low activity). By pulse-labeling with (/sup 35/S)methionine, immune precipitation, and isoelectric focusing under dissociating conditions, we have measured the relative rates of synthesis of the two types of enzyme subunit in animals of genotypes Mdr-1/sup a/ Mod-2/sup a//Mdr-1/sup a/ Mod-2/sup b/ and Mdr-1/sup a/ Mod-2/sup a//Mdr-1/sup b/ Mod-2/sup b/. The results show that in the former animals both types of subunit are made at an identical rate, whereas in the latter animals the Mod-2/sup a/ gene product is synthesized at a rate 2.2 times that of the Mod-2/sup b/-coded subunit. Thus we have unambiguously demonstrated that Mdr-1 is cis-active in its control of the expression of the Mod-2 structural gene.

  18. Investigations of DNA damage induction and repair resulting from cellular exposure to high dose-rate pulsed proton beams

    NASA Astrophysics Data System (ADS)

    Renis, M.; Borghesi, M.; Favetta, M.; Malfa, G.; Manti, L.; Romano, F.; Schettino, G.; Tomasello, B.; Cirrone, G. A. P.

    2013-07-01

    Studies regarding the radiobiological effects of low dose radiation, microbeam irradiation services have been developed in the world and today laser acceleration of protons and heavy ions may be used in radiation therapy. The application of different facilities is essential for studying bystander effects and relating signalling phenomena in different cells or tissues. In particular the use of ion beams results advantageous in cancer radiotherapy compared to more commonly used X-rays, since the ability of ions in delivering lethal amount of doses into the target tumour avoiding or limiting damage to the contiguous healthy tissues. At the INFN-LNS in Catania, a multidisciplinary radiobiology group is strategically structured aimed to develop radiobiological research, finalised to therapeutic applications, compatible with the use of high dose laser-driven ion beams. The characteristic non-continuous dose rates with several orders of magnitude of laser-driven ion beams makes this facility very interesting in the cellular systems' response to ultra-high dose rates with non-conventional pulse time intervals cellular studies. Our group have projected to examine the effect of high dose laser-driven ion beams on two cellular types: foetal fibroblasts (normal control cells) and DU145 (prostate cancer cells), studying the modulation of some different bio-molecular parameters, in particular cell proliferation and viability, DNA damage, redox cellular status, morphological alterations of both the cytoskeleton components and some cell organelles and the possible presence of apoptotic or necrotic cell death. Our group performed preliminary experiments with high energy (60 MeV), dose rate of 10 Gy/min, doses of 1, 2, 3 Gy and LET 1 keV/μm on human foetal fibroblasts (control cells). We observed that cell viability was not influenced by the characteristics of the beam, the irradiation conditions or the analysis time. Conversely, DNA damage was present at time 0, immediately

  19. Investigations of DNA damage induction and repair resulting from cellular exposure to high dose-rate pulsed proton beams

    SciTech Connect

    Renis, M.; Malfa, G.; Tomasello, B.; Borghesi, M.; Schettino, G.; Favetta, M.; Romano, F.; Cirrone, G. A. P.; Manti, L.

    2013-07-26

    Studies regarding the radiobiological effects of low dose radiation, microbeam irradiation services have been developed in the world and today laser acceleration of protons and heavy ions may be used in radiation therapy. The application of different facilities is essential for studying bystander effects and relating signalling phenomena in different cells or tissues. In particular the use of ion beams results advantageous in cancer radiotherapy compared to more commonly used X-rays, since the ability of ions in delivering lethal amount of doses into the target tumour avoiding or limiting damage to the contiguous healthy tissues. At the INFN-LNS in Catania, a multidisciplinary radiobiology group is strategically structured aimed to develop radiobiological research, finalised to therapeutic applications, compatible with the use of high dose laser-driven ion beams. The characteristic non-continuous dose rates with several orders of magnitude of laser-driven ion beams makes this facility very interesting in the cellular systems' response to ultra-high dose rates with non-conventional pulse time intervals cellular studies. Our group have projected to examine the effect of high dose laser-driven ion beams on two cellular types: foetal fibroblasts (normal control cells) and DU145 (prostate cancer cells), studying the modulation of some different bio-molecular parameters, in particular cell proliferation and viability, DNA damage, redox cellular status, morphological alterations of both the cytoskeleton components and some cell organelles and the possible presence of apoptotic or necrotic cell death. Our group performed preliminary experiments with high energy (60 MeV), dose rate of 10 Gy/min, doses of 1, 2, 3 Gy and LET 1 keV/μm on human foetal fibroblasts (control cells). We observed that cell viability was not influenced by the characteristics of the beam, the irradiation conditions or the analysis time. Conversely, DNA damage was present at time 0, immediately

  20. The relationship between specific absorption rate and temperature elevation in anatomically based human body models for plane wave exposure from 30 MHz to 6 GHz

    NASA Astrophysics Data System (ADS)

    Hirata, Akimasa; Laakso, Ilkka; Oizumi, Takuya; Hanatani, Ryuto; Chan, Kwok Hung; Wiart, Joe

    2013-02-01

    According to the international safety guidelines/standard, the whole-body-averaged specific absorption rate (Poljak et al 2003 IEEE Trans. Electromagn. Compat. 45 141-5) and the peak spatial average SAR are used as metrics for human protection from whole-body and localized exposures, respectively. The IEEE standard (IEEE 2006 IEEE C95.1) indicates that the upper boundary frequency, over which the whole-body-averaged SAR is deemed to be the basic restriction, has been reduced from 6 to 3 GHz, because radio-wave energy is absorbed around the body surface when the frequency is increased. However, no quantitative discussion has been provided to support this description especially from the standpoint of temperature elevation. It is of interest to investigate the maximum temperature elevation in addition to the core temperature even for a whole-body exposure. In the present study, using anatomically based human models, we computed the SAR and the temperature elevation for a plane-wave exposure from 30 MHz to 6 GHz, taking into account the thermoregulatory response. As the primary result, we found that the ratio of the core temperature elevation to the whole-body-averaged SAR is almost frequency independent for frequencies below a few gigahertz; the ratio decreases above this frequency. At frequencies higher than a few gigahertz, core temperature elevation for the same whole-body averaged SAR becomes lower due to heat convection from the skin to air. This lower core temperature elevation is attributable to skin temperature elevation caused by the power absorption around the body surface. Then, core temperature elevation even for whole-body averaged SAR of 4 W kg-1 with the duration of 1 h was at most 0.8 °C, which is smaller than a threshold considered in the safety guidelines/standard. Further, the peak 10 g averaged SAR is correlated with the maximum body temperature elevations without extremities and pinna over the frequencies considered. These findings were confirmed

  1. Does the cortical bone resorption rate change due to 90Sr-radiation exposure? Analysis of data from Techa Riverside residents

    SciTech Connect

    Tolstykh, E I; Shagina, N B; Degteva, M O; Anspaugh, L R; Napier, Bruce A

    2011-08-01

    The Mayak Production Association released large amounts of 90Sr into the Techa River (Southern Urals, Russia) with peak amounts in 1950-1951. Techa Riverside residents ingested an average of about 3,000 kBq of 90Sr. The 90Sr-body burden of approximately 15,000 individuals has been measured in the Urals Research Center for Radiation Medicine in 1974-1997 with use of a special whole-body counter (WBC). Strontium-90 had mainly deposited in the cortical part of the skeleton by 25 years following intake, and 90Sr elimination occurs as a result of cortical bone resorption. The effect of 90Sr-radiation exposure on the rate of cortical bone resorption was studied. Data on 2,022 WBC measurements were selected for 207 adult persons, who were measured three or more times before they were 50-55 years old. The individual-resorption rates were calculated with the rate of strontium recirculation evaluated as 0.0018 year-1. Individual absorbed doses in red bone marrow (RBM) and bone surface (BS) were also calculated. Statistically significant negative relationships of cortical bone resorption rate were discovered related to 90Sr-body burden and dose absorbed in the RBM or the BS. The response appears to have a threshold of about 1.5-Gy RBM dose. The radiation induced decrease in bone resorption rate may not be significant in terms of health. However, a decrease in bone remodeling rate can be among several causes of an increased level of degenerative dystrophic bone pathology in exposed persons.

  2. Post-exposure rate of tuberculosis infection among health care workers measured with tuberculin skin test conversion after unprotected exposure to patients with pulmonary tuberculosis: 6-year experience in an Italian teaching hospital

    PubMed Central

    2014-01-01

    Background This study assesses the risk of LTBI at our Hospital among HCWs who have been exposed to TB patients with a delayed diagnosis and respiratory protection measures were not implemented. Methods All HCWs exposed to a patient with cultural confirmed pulmonary TB and respiratory protection measures were not implemented were included. Data on TST results performed in the past (defined as T0) were recorded. TST was performed twice: first, immediately after exposure to an index patient (T1) and three months later (T2). The period of time between T0 and T1 was used to calculate he annual rate of tuberculosis infection (ARTI), while le period of time between T1 and T2 was used to calculate the post exposure annual rate of tuberculosis infection (PEARTI). Results Fourteen index patients were admitted; sputum smear was positive in 7 (58.3%), 4 (28.6%) were non-Italian born patients. 388 HCWs were exposed to index patients, a median of 27 (12-39) HCW per each index patient. One hundred eighty (46.4%) HCWs received BCG in the past. One hundred twenty two HCWs (31%) were TST positive at a previous routine screening and not evaluated in this subset. Among the remaining 255 HCWs with negative TST test in the past, TST at T1 was positive in 11 (4.3%). ARTI was 1.6 (95% CI 0.9-2.9) per 100 PY. TST at T2 was positive in 9 (3.7%) HCWs, that were TST negative at T1. PEARTI was 26 (95% CI 13.6-50) per 100 PY. At univariate analysis, older age was associated with post exposure latent tuberculosis infection (HR 1.12; 95% CI 1.03-1.22, p=0.01). Conclusions PEARTI was considerably higher among HCWs exposed to index patients than ARTI. These data underscore the overwhelming importance of performing a rapid diagnosis, as well as implementing adequate respiratory protection measures when TB is suspected. PMID:24919953

  3. Kinetic analysis of the temperature dependence of PbSe colloidal quantum dot photoluminescence: Effects of synthesis process and oxygen exposure

    NASA Astrophysics Data System (ADS)

    Foell, Charles A.; Abel, Keith A.; van Veggel, Frank C. J. M.; Young, Jeff F.

    2014-01-01

    A kinetic model is derived and used to analyze recently published works and new data on the temperature dependence of the spectrally integrated photoluminescence (PL) from thick-film formulations of PbSe colloidal quantum dots (QDs), with particular attention to the effects of air exposure. The model assumes that the excitons thermalize within a ground-state manifold of states and treats the distribution of radiative and nonradiative decay rates within the distribution as generally as possible, while using a minimal number of free parameters. By adjusting the parameters of the model, good fits are obtained for the wide range of integrated PL behaviors reported in [J. Phys. Chem. Lett. 2, 889 (2011), 10.1021/jz2001979; ACS Nano 6, 5498 (2012), 10.1021/nn301405j; Phys. Rev. B 82, 165435 (2010), 10.1103/PhysRevB.82.165435] and the new data presented in this manuscript. By comparing the extracted parameters we deduce the following: (i) All of the samples in the first two references emit from two distinct clusters of states separated by an energy of 55 to 80 meV regardless of air exposure, while there is only one cluster of emissive states that contributes to the emission reported in the third reference. (ii) In the absence of intentional air exposure, the nonradiative decay from all samples can be described by a single Arrhenius-like process. (iii) Although air-exposure effects are reversible in some samples and irreversible in others, the changes in integrated PL behavior brought about by air-exposure forces the introduction of a common, low-activation-energy nonradiative pathway in all cases. (iv) The low-lying emissive cluster of the two-emissive-cluster samples exhibits behavior similar to the single emissive cluster of the other samples. (v) Many hours of air exposure do not trend either the radiative or nonradiative behavior of the dual-emissive-cluster samples towards the behavior of the single-emissive-cluster samples.

  4. The rate of polymerase release upon filling the gap between Okazaki fragments is inadequate to support cycling during lagging strand synthesis.

    PubMed

    Dohrmann, Paul R; Manhart, Carol M; Downey, Christopher D; McHenry, Charles S

    2011-11-18

    Upon completion of synthesis of an Okazaki fragment, the lagging strand replicase must recycle to the next primer at the replication fork in under 0.1 s to sustain the physiological rate of DNA synthesis. We tested the collision model that posits that cycling is triggered by the polymerase encountering the 5'-end of the preceding Okazaki fragment. Probing with surface plasmon resonance, DNA polymerase III holoenzyme initiation complexes were formed on an immobilized gapped template. Initiation complexes exhibit a half-life of dissociation of approximately 15 min. Reduction in gap size to 1 nt increased the rate of dissociation 2.5-fold, and complete filling of the gap increased the off-rate an additional 3-fold (t(1/2)~2 min). An exogenous primed template and ATP accelerated dissociation an additional 4-fold in a reaction that required complete filling of the gap. Neither a 5'-triphosphate nor a 5'-RNA terminated oligonucleotide downstream of the polymerase accelerated dissociation further. Thus, the rate of polymerase release upon gap completion and collision with a downstream Okazaki fragment is 1000-fold too slow to support an adequate rate of cycling and likely provides a backup mechanism to enable polymerase release when the other cycling signals are absent. Kinetic measurements indicate that addition of the last nucleotide to fill the gap is not the rate-limiting step for polymerase release and cycling. Modest (approximately 7 nt) strand displacement is observed after the gap between model Okazaki fragments is filled. To determine the identity of the protein that senses gap filling to modulate affinity of the replicase for the template, we performed photo-cross-linking experiments with highly reactive and non-chemoselective diazirines. Only the α subunit cross-linked, indicating that it serves as the sensor.

  5. Temporal Variation for the Expression of Catalase in DROSOPHILA MELANOGASTER: Correlations between Rates of Enzyme Synthesis and Levels of Translatable Catalase-Messenger RNA

    PubMed Central

    Bewley, Glenn C.; Mackay, William J.; Cook, Julia L.

    1986-01-01

    Two variants that alter the temporal expression of catalase have been isolated from a set of third chromosome substitution lines. Each variant has been mapped to a cytogenetic interval flanked by the visible markers st (3-44.0) and cu (3-50.0) at a map position of 47.0, which is within or near the interval 75D-76A previously identified as containing the catalase structural gene on the bases of dosage responses to segmental aneuploidy. Each variant operates by modulating the rate of enzyme synthesis and the level of translatable catalase-mRNA. PMID:3091448

  6. Differential response of planktonic primary, bacterial, and dimethylsulfide production rates to static vs. dynamic light exposure in upper mixed-layer summer sea waters

    NASA Astrophysics Data System (ADS)

    Galí, M.; Simó, R.; Pérez, G. L.; Ruiz-González, C.; Sarmento, H.; Royer, S.-J.; Fuentes-Lema, A.; Gasol, J. M.

    2013-12-01

    Microbial plankton experience short-term fluctuations in total solar irradiance and in its spectral composition as they are vertically moved by turbulence in the oceanic upper mixed layer (UML). The fact that the light exposure is not static but dynamic may have important consequences for biogeochemical processes and ocean-atmosphere fluxes. However, most biogeochemical processes other than primary production, like bacterial production or dimethylsulfide (DMS) production, are seldom measured in sunlight and even less often in dynamic light fields. We conducted four experiments in oligotrophic summer stratified Mediterranean waters, where a sample from the UML was incubated in ultraviolet (UV)-transparent bottles at three fixed depths within the UML and on a vertically moving basket across the same depth range. We assessed the response of the phyto- and bacterioplankton community with physiological indicators based on flow cytometry singe-cell measurements, fast repetition rate fluorometry (FRRf), phytoplankton pigment concentrations and particulate light absorption. Dynamic light exposure caused a subtle disruption of the photoinhibition and photoacclimation processes associated with ultraviolet radiation (UVR), which slightly alleviated bacterial photoinhibition but did not favor primary production. Gross DMS production (GPDMS) decreased sharply with depth in parallel to shortwave UVR, and displayed a dose-dependent response that mixing did not significantly disrupt. To our knowledge, we provide the first measurements of GPDMS under in situ UV-inclusive optical conditions.

  7. Distinct Effects of Nalmefene on Dopamine Uptake Rates and Kappa Opioid Receptor Activity in the Nucleus Accumbens Following Chronic Intermittent Ethanol Exposure.

    PubMed

    Rose, Jamie H; Karkhanis, Anushree N; Steiniger-Brach, Björn; Jones, Sara R

    2016-01-01

    The development of pharmacotherapeutics that reduce relapse to alcohol drinking in patients with alcohol dependence is of considerable research interest. Preclinical data support a role for nucleus accumbens (NAc) κ opioid receptors (KOR) in chronic intermittent ethanol (CIE) exposure-induced increases in ethanol intake. Nalmefene, a high-affinity KOR partial agonist, reduces drinking in at-risk patients and relapse drinking in rodents, potentially due to its effects on NAc KORs. However, the effects of nalmefene on accumbal dopamine transmission and KOR function are poorly understood. We investigated the effects of nalmefene on dopamine transmission and KORs using fast scan cyclic voltammetry in NAc brain slices from male C57BL/6J mice following five weeks of CIE or air exposure. Nalmefene concentration-dependently reduced dopamine release similarly in air and CIE groups, suggesting that dynorphin tone may not be present in brain slices. Further, nalmefene attenuated dopamine uptake rates to a greater extent in brain slices from CIE-exposed mice, suggesting that dopamine transporter-KOR interactions may be fundamentally altered following CIE. Additionally, nalmefene reversed the dopamine-decreasing effects of a maximal concentration of a KOR agonist selectively in brain slices of CIE-exposed mice. It is possible that nalmefene may attenuate withdrawal-induced increases in ethanol consumption by modulation of dopamine transmission through KORs. PMID:27472317

  8. The impacts of short-term exposure to noise and traffic-related air pollution on heart rate variability in young healthy adults.

    PubMed

    Huang, Jing; Deng, Furong; Wu, Shaowei; Lu, Henry; Hao, Yu; Guo, Xinbiao

    2013-01-01

    Traffic-related air pollution and noise are associated with cardiovascular diseases, and alternation of heart rate variability (HRV), which reflects cardiac autonomic function, is one of the mechanisms. However, few studies considered the impacts of noise when exploring associations between air pollution and HRV. We explored whether noise modifies associations between short-term exposure to traffic-related air pollution and HRV in young healthy adults. In this randomized, crossover study, 40 young healthy adults stayed for 2 h in a traffic center and, on a separate occasion, in a park. Personal exposure to traffic-related air pollutants and noise were measured and ambulatory electrocardiogram was performed. Effects were estimated using mixed-effects regression models. Traffic-related air pollution and noise were both associated with HRV, and effects of air pollutants were amplified at high noise level (>65.6 A-weighted decibels (dB[A])) compared with low noise level (≤ 65.6 dB[A]). High frequency (HF) decreased by -4.61% (95% confidence interval, -6.75% to-2.42%) per 10 μg/m(3) increment in fine particle (PM2.5) at 5-min moving average, but effects became insignificant at low noise level (P>0.05). Similar effects modification was observed for black carbon (BC) and carbon monoxide (CO). We conclude that noise is an important factor influencing the effects of air pollution on HRV.

  9. Distinct Effects of Nalmefene on Dopamine Uptake Rates and Kappa Opioid Receptor Activity in the Nucleus Accumbens Following Chronic Intermittent Ethanol Exposure.

    PubMed

    Rose, Jamie H; Karkhanis, Anushree N; Steiniger-Brach, Björn; Jones, Sara R

    2016-07-27

    The development of pharmacotherapeutics that reduce relapse to alcohol drinking in patients with alcohol dependence is of considerable research interest. Preclinical data support a role for nucleus accumbens (NAc) κ opioid receptors (KOR) in chronic intermittent ethanol (CIE) exposure-induced increases in ethanol intake. Nalmefene, a high-affinity KOR partial agonist, reduces drinking in at-risk patients and relapse drinking in rodents, potentially due to its effects on NAc KORs. However, the effects of nalmefene on accumbal dopamine transmission and KOR function are poorly understood. We investigated the effects of nalmefene on dopamine transmission and KORs using fast scan cyclic voltammetry in NAc brain slices from male C57BL/6J mice following five weeks of CIE or air exposure. Nalmefene concentration-dependently reduced dopamine release similarly in air and CIE groups, suggesting that dynorphin tone may not be present in brain slices. Further, nalmefene attenuated dopamine uptake rates to a greater extent in brain slices from CIE-exposed mice, suggesting that dopamine transporter-KOR interactions may be fundamentally altered following CIE. Additionally, nalmefene reversed the dopamine-decreasing effects of a maximal concentration of a KOR agonist selectively in brain slices of CIE-exposed mice. It is possible that nalmefene may attenuate withdrawal-induced increases in ethanol consumption by modulation of dopamine transmission through KORs.

  10. Distinct Effects of Nalmefene on Dopamine Uptake Rates and Kappa Opioid Receptor Activity in the Nucleus Accumbens Following Chronic Intermittent Ethanol Exposure

    PubMed Central

    Rose, Jamie H.; Karkhanis, Anushree N.; Steiniger-Brach, Björn; Jones, Sara R.

    2016-01-01

    The development of pharmacotherapeutics that reduce relapse to alcohol drinking in patients with alcohol dependence is of considerable research interest. Preclinical data support a role for nucleus accumbens (NAc) κ opioid receptors (KOR) in chronic intermittent ethanol (CIE) exposure-induced increases in ethanol intake. Nalmefene, a high-affinity KOR partial agonist, reduces drinking in at-risk patients and relapse drinking in rodents, potentially due to its effects on NAc KORs. However, the effects of nalmefene on accumbal dopamine transmission and KOR function are poorly understood. We investigated the effects of nalmefene on dopamine transmission and KORs using fast scan cyclic voltammetry in NAc brain slices from male C57BL/6J mice following five weeks of CIE or air exposure. Nalmefene concentration-dependently reduced dopamine release similarly in air and CIE groups, suggesting that dynorphin tone may not be present in brain slices. Further, nalmefene attenuated dopamine uptake rates to a greater extent in brain slices from CIE-exposed mice, suggesting that dopamine transporter-KOR interactions may be fundamentally altered following CIE. Additionally, nalmefene reversed the dopamine-decreasing effects of a maximal concentration of a KOR agonist selectively in brain slices of CIE-exposed mice. It is possible that nalmefene may attenuate withdrawal-induced increases in ethanol consumption by modulation of dopamine transmission through KORs. PMID:27472317

  11. Co-ingestion of leucine with protein does not further augment post-exercise muscle protein synthesis rates in elderly men.

    PubMed

    Koopman, René; Verdijk, Lex B; Beelen, Milou; Gorselink, Marchel; Kruseman, Arie Nieuwenhuijzen; Wagenmakers, Anton J M; Kuipers, Harm; van Loon, Luc J C

    2008-03-01

    Leucine has been suggested to have the potential to modulate muscle protein metabolism by increasing muscle protein synthesis. The objective of this study was to investigate the surplus value of the co-ingestion of free leucine with protein hydrolysate and carbohydrate following physical activity in elderly men. Eight elderly men (mean age 73 +/- 1 years) were randomly assigned to two cross-over treatments consuming either carbohydrate and protein hydrolysate (CHO+PRO) or carbohydrate, protein hydrolysate with additional leucine (CHO+PRO+leu) after performing 30 min of standardized physical activity. Primed, continuous infusions with L-[ring-(13)C(6)]phenylalanine and L-[ring-(2)H(2)]tyrosine were applied, and blood and muscle samples were collected to assess whole-body protein turnover as well as protein fractional synthetic rate in the vastus lateralis muscle over a 6 h period. Whole-body protein breakdown and synthesis rates were not different between treatments. Phenylalanine oxidation rates were significantly lower in the CHO+PRO+leu v. CHO+PRO treatment. As a result, whole-body protein balance was significantly greater in the CHO+PRO+leu compared to the CHO+PRO treatment (23.8 (SEM 0.3) v. 23.2 (SEM 0.3) micromol/kg per h, respectively; P < 0.05). Mixed muscle fractional synthetic rate averaged 0.081 (SEM 0.003) and 0.082 (SEM 0.006) %/h in the CHO+PRO+leu and CHO+PRO treatment, respectively (NS). Co-ingestion of leucine with carbohydrate and protein following physical activity does not further elevate muscle protein fractional synthetic rate in elderly men when ample protein is ingested. PMID:17697406

  12. Ice-based altitude distribution of natural radiation annual exposure rate in the Antarctica zone over the latitude range 69 degrees S-77 degrees S using a pair-filter thermoluminescence method.

    PubMed

    Nakajima, T; Kamiyama, T; Fujii, Y; Motoyama, H; Esumi, S

    1995-12-01

    Both ice-based altitude distributions of natural ionizing radiation exposure and the quasi-effective energy of natural radiation over Antartica over the latitude range 69 degrees S - 77 degrees S during approx. 500 days were measured using thermoluminescent dosimeters. The results shows that dependence on altitude above sea level of the exposure rate increases by almost three-fold with each increase of 2000 m of altitude, thus deviating from the general rule stating that the exposure rate should double with each 2000 m. Although the exposure rate shows a dependence on altitude, altitude dependence of the quasi-effective energy of natural radiation over Antartica is not observed. In the present study it is observed that natural radiation occurring over the ice base of Antartica consists mainly of cosmic rays. PMID:8563705

  13. Ice-based altitude distribution of natural radiation annual exposure rate in the Antarctica zone over the latitude range 69 degrees S-77 degrees S using a pair-filter thermoluminescence method.

    PubMed

    Nakajima, T; Kamiyama, T; Fujii, Y; Motoyama, H; Esumi, S

    1995-12-01

    Both ice-based altitude distributions of natural ionizing radiation exposure and the quasi-effective energy of natural radiation over Antartica over the latitude range 69 degrees S - 77 degrees S during approx. 500 days were measured using thermoluminescent dosimeters. The results shows that dependence on altitude above sea level of the exposure rate increases by almost three-fold with each increase of 2000 m of altitude, thus deviating from the general rule stating that the exposure rate should double with each 2000 m. Although the exposure rate shows a dependence on altitude, altitude dependence of the quasi-effective energy of natural radiation over Antartica is not observed. In the present study it is observed that natural radiation occurring over the ice base of Antartica consists mainly of cosmic rays.

  14. γ-H2AX responds to DNA damage induced by long-term exposure to combined low-dose-rate neutron and γ-ray radiation.

    PubMed

    Zhang, Junlin; He, Ying; Shen, Xianrong; Jiang, Dingwen; Wang, Qingrong; Liu, Qiong; Fang, Wen

    2016-01-01

    Risk estimates for low-dose radiation (LDR) remain controversial. The possible involvement of DNA repair-related genes in long-term low-dose-rate neutron-gamma radiation exposure is poorly understood. In this study, 60 rats were divided into control groups and irradiated groups, which were exposed to low-dose-rate n-γ combined radiation (LDCR) for 15, 30, or 60 days. The effects of different cumulative radiation doses on peripheral blood cell (PBC), subsets of T cells of peripheral blood lymphocytes (PBL) and DNA damage repair were investigated. Real-time PCR and immunoblot analyses were used to detect expression of DNA DSB-repair-related genes involved in the NHEJ pathway, such as Ku70 and Ku80, in PBL. The mRNA level of H2AX and the expression level of γ-H2AX were detected by real-time PCR, immunoblot, and flow cytometry. White blood cells (WBC) and platelets (PLT) of all ionizing radiation (IR) groups decreased significantly, while no difference was seen between the 30 day and 60 day exposure groups. The numbers of CD3(+), CD4(+) T cells and CD4(+)/CD8(+) in the PBL of IR groups were lower than in the control group. In the 30 day and 60 day exposure groups, CD8(+) T cells decreased significantly. Real-time PCR and immunoblot results showed no significant difference in the mRNA and protein expression of Ku70 and Ku80 between the control groups and IR groups. However, the mRNA of H2AX increased significantly, and there was a positive correlation with dose. There was no difference in the protein expression of γ-H2AX between 30 day and 60 day groups, which may help to explain the damage to PBL. In conclusion, PBL damage increased with cumulative dose, suggesting that γ-H2AX, but neither Ku70 nor Ku80, plays an important role in PBL impairment induced by LDCR.

  15. Post-vitrification survival and in vitro maturation rate of buffalo (Bubalus bubalis) oocytes: effect of ethylene glycol concentration and exposure time.

    PubMed

    Dhali, A; Manik, R S; Das, S K; Singla, S K; Palta, P

    2000-11-01

    The present study was undertaken to investigate the effects of ethylene glycol concentration and time of exposure to equilibration solution on the post-thaw morphological appearance and the in vitro maturation rate of buffalo oocytes. Vitrification solution-I (VS-I) consisted of 4.5M ethylene glycol (EG), 3.4M dimethyl sulphoxide, 5. 56mM glucose, 0.33mM sodium pyruvate and 0.4% w/v bovine serum albumin in Dulbecco's phosphate buffered saline (DPBS), whereas vitrification solution-II (VS-II) contained 3.5M EG, with other constituents at same concentrations as in VS-I. The equilibration solutions-I and II were prepared by 50% dilution (v/v) of VS-I and VS-II, respectively, in DPBS. Prior to vitrification, the cumulus-oocyte complexes (COCs) were exposed to equilibration solution-I or II for 1 or 3min at room temperature (25-30 degrees C). Groups of four to five oocytes were then placed in 15microl of respective vitrification solution, and immediately loaded into 0. 25ml French straws, each containing 150microl of 0.5M sucrose in DPBS. The straws were placed in liquid nitrogen (LN(2)) vapour for 2min, plunged and stored in LN(2) for at least 7 days. The straws were thawed by keeping in warm water at 28 degrees C for 20s, and the oocytes were equilibrated for 5min in 0.5M sucrose for one-step dilution. The percentage of oocytes found to be morphologically normal varied from 89 to 96% for the two equilibration solutions and the two exposure times. Among the damaged oocytes, cracking of zona pellucida was the abnormality observed most frequently. The nuclear maturation rate of oocytes equilibrated in equilibration solutions-I and II for 1 (28 and 24%, respectively) or 3min (32 and 33%, respectively) did not differ significantly. These results show that it is possible to cryopreserve buffalo oocytes by vitrification using a combination of 3.5M EG and 3.4M DMSO with an exposure time of 3min.

  16. Multi-color carrier-envelope-phase stabilization for high-repetition-rate multi-pulse coherent synthesis.

    PubMed

    McCracken, Richard A; Gianani, Ilaria; Wyatt, Adam S; Reid, Derryck T

    2015-04-01

    Using a zero-offset carrier-envelope locking technique, we have synthesized an octave-spanning composite frequency comb exhibiting 132-attosecond timing jitter between the constituent pulses over a one-second observation window. In the frequency domain, this composite comb has a modal structure and coherence which are indistinguishable from those of a comb that might be produced by a hypothetical single mode locked oscillator of equivalent bandwidth. The associated phase stability enables the participating multi-color pulse sequences to be coherently combined, representing an example of multi-pulse synthesis using a femtosecond oscillator.

  17. Different rates of synthesis and degradation of two chloroplastic ammonium-inducible NADP-specific glutamate dehydrogenase isoenzymes during induction and deinduction in Chlorella sorokiniana cells

    SciTech Connect

    Bascomb, N.F.; Prunkard, D.E.; Schmidt, R.R.

    1987-01-01

    The kinetics of accumulation (per milliliter of culture) of the ..cap alpha..- and ..beta..-subunits, associated with chloroplast-localized ammonium inducible nicotinamide adenine dinucleotide phosphate-specific glutamate dehydrogenase (NADP-GDH) isoenzymes, were measured during a 3 hour induction of synchronized daughter cells of Chlorella sorokiniana in 29 millimolar ammonium medium under photoautotrophic conditions. The ..beta..-subunit holoenzyme(s) accumulated in a linear manner for 3 hours without an apparent induction lag. A 40 minute induction lag preceded the accumulation of the ..cap alpha..-subunit holoenzyme(s). After 120 minutes, the ..cap alpha..-subunit ceased accumulating and thereafter remained at a constant level. From pulse-chase experiments, using /sup 35/SO/sub 4/ and immunochemical procedures, the rate of synthesis of the ..cap alpha..-subunit was shown to be greater than the ..beta..-subunit during the first 80 minutes of induction. The ..cap alpha..- and ..beta..-subunits had different rates of degradation during the induction period (t/sub 1/2/ = 50 versus 150 minutes, respectively) and during the deinduction period (t/sub 1/2/ = 5 versus 13.5 minutes) after removal of ammonium from the culture. During deinduction, total NADP-GDH activity decreased with a half-time of 9 minutes. Cycloheximide completely inhibited the synthesis and degradation of both subunits. A model for regulation of expression of the NADP-GDH gene was proposed.

  18. Determining Degradation and Synthesis Rates of Arabidopsis Proteins Using the Kinetics of Progressive 15N Labeling of Two-dimensional Gel-separated Protein Spots*

    PubMed Central

    Li, Lei; Nelson, Clark J.; Solheim, Cory; Whelan, James; Millar, A. Harvey

    2012-01-01

    The growth and development of plant tissues is associated with an ordered succession of cellular processes that are reflected in the appearance and disappearance of proteins. The control of the kinetics of protein turnover is central to how plants can rapidly and specifically alter protein abundance and thus molecular function in response to environmental or developmental cues. However, the processes of turnover are largely hidden during periods of apparent steady-state protein abundance, and even when proteins accumulate it is unclear whether enhanced synthesis or decreased degradation is responsible. We have used a 15N labeling strategy with inorganic nitrogen sources coupled to a two-dimensional fluorescence difference gel electrophoresis and mass spectrometry analysis of two-dimensional IEF/SDS-PAGE gel spots to define the rate of protein synthesis (KS) and degradation (KD) of Arabidopsis cell culture proteins. Through analysis of MALDI-TOF/TOF mass spectra from 120 protein spots, we were able to quantify KS and KD for 84 proteins across six functional groups and observe over 65-fold variation in protein degradation rates. KS and KD correlate with functional roles of the proteins in the cell and the time in the cell culture cycle. This approach is based on progressive 15N labeling that is innocuous for the plant cells and, because it can be used to target analysis of proteins through the use of specific gel spots, it has broad applicability. PMID:22215636

  19. Effect of gas flow rates on the anatase-rutile transformation temperature of nanocrystalline TiO2 synthesised by chemical vapour synthesis.

    PubMed

    Ahmad, Md Imteyaz; Bhattacharya, S S; Fasel, Claudia; Hahn, Horst

    2009-09-01

    Of the three crystallographic allotropes of nanocrystalline titania (rutile, anatase and brookite), anatase exhibits the greatest potential for a variety of applications, especially in the area of catalysis and sensors. However, with rutile being thermodynamically the most stable phase, anatase tends to transform into rutile on heating to temperatures in the range of 500 degrees C to 700 degrees C. Efforts made to stabilize the anatase phase at higher temperatures by doping with metal oxides suffer from the problems of having a large amorphous content on synthesis as well as the formation of secondary impurity phases on doping. Recent studies have suggested that the as-synthesised phase composition, crystallite size, initial surface area and processing conditions greatly influence the anatase to rutile transformation temperature. In this study nanocrystalline titania was synthesised in the anatase form bya chemical vapour synthesis (CVS) method using titanium tetra iso-propoxide (TTIP) as a precursor under varying flow rates of oxygen and helium. The anatase to rutile transformation was studied using high temperature X-ray diffraction (HTXRD) and simultaneous thermogravimetric analysis (STA), followed by transmission electron microscopy (TEM). It was demonstrated that the anatase-rutile transformation temperatures were dependent on the oxygen to helium flow rate ratio during CVS and the results are presented and discussed. PMID:19928267

  20. Testosterone increases the muscle protein synthesis rate but does not affect very-low-density lipoprotein metabolism in obese premenopausal women

    PubMed Central

    Wang, Xuewen; Smith, Gordon I.; Patterson, Bruce W.; Reeds, Dominic N.; Kampelman, Janine; Magkos, Faidon

    2012-01-01

    Men and women with hyperandrogenemia have a more proatherogenic plasma lipid profile [e.g., greater triglyceride (TG) and total and low-density lipoprotein-cholesterol and lower high-density lipoprotein-cholesterol concentrations] than healthy premenopausal women. Furthermore, castration of male rats markedly reduces testosterone availability below normal and decreases plasma TG concentration, and testosterone replacement reverses this effect. Testosterone is, therefore, thought to be an important regulator of plasma lipid homeostasis. However, little is known about the effect of testosterone on plasma TG concentration and kinetics. Furthermore, testosterone is a potent skeletal muscle protein anabolic agent in men, but its effect on muscle protein turnover in women is unknown. We measured plasma lipid concentrations, hepatic very low density lipoprotein (VLDL)-TG and VLDL-apolipoprotein B-100 secretion rates, and the muscle protein fractional synthesis rate in 10 obese women before and after trandermal testosterone (1.25 g of 1% AndroGel daily) treatment for 3 wk. Serum total and free testosterone concentrations increased (P < 0.05) by approximately sevenfold in response to testosterone treatment, reaching concentrations that are comparable to those in women with hyperandrogenemia, but lower than the normal range for eugonadal men. Except for a small (∼10%) decrease in plasma high-density lipoprotein particle and cholesterol concentrations (P < 0.04), testosterone therapy had no effect on plasma lipid concentrations, lipoprotein particle sizes, and hepatic VLDL-TG and VLDL-apolipoprotein B-100 secretion rates (all P > 0.05); the muscle protein fractional synthesis rate, however, increased by ∼45% (P < 0.001). We conclude that testosterone is a potent skeletal muscle protein anabolic agent, but not an important regulator of plasma lipid homeostasis in obese women. PMID:22252942

  1. Air Change Rates and Interzonal Flows in Residences, and the Need for Multi-Zone Models for Exposure and Health Analyses

    PubMed Central

    Du, Liuliu; Batterman, Stuart; Godwin, Christopher; Chin, Jo-Yu; Parker, Edith; Breen, Michael; Brakefield, Wilma; Robins, Thomas; Lewis, Toby

    2012-01-01

    Air change rates (ACRs) and interzonal flows are key determinants of indoor air quality (IAQ) and building energy use. This paper characterizes ACRs and interzonal flows in 126 houses, and evaluates effects of these parameters on IAQ. ACRs measured using weeklong tracer measurements in several seasons averaged 0.73 ± 0.76 h−1 (median = 0.57 h−1, n = 263) in the general living area, and much higher, 1.66 ± 1.50 h−1 (median = 1.23 h−1, n = 253) in bedrooms. Living area ACRs were highest in winter and lowest in spring; bedroom ACRs were highest in summer and lowest in spring. Bedrooms received an average of 55 ± 18% of air from elsewhere in the house; the living area received only 26 ± 20% from the bedroom. Interzonal flows did not depend on season, indoor smoking or the presence of air conditioners. A two-zone IAQ model calibrated for the field study showed large differences in pollutant levels between the living area and bedroom, and the key parameters affecting IAQ were emission rates, emission source locations, air filter use, ACRs, interzonal flows, outdoor concentrations, and PM penetration factors. The single-zone models that are commonly used for residences have substantial limitations and may inadequately represent pollutant concentrations and exposures in bedrooms and potentially other environments other where people spend a substantial fraction of time. PMID:23235286

  2. Air change rates and interzonal flows in residences, and the need for multi-zone models for exposure and health analyses.

    PubMed

    Du, Liuliu; Batterman, Stuart; Godwin, Christopher; Chin, Jo-Yu; Parker, Edith; Breen, Michael; Brakefield, Wilma; Robins, Thomas; Lewis, Toby

    2012-12-12

    Air change rates (ACRs) and interzonal flows are key determinants of indoor air quality (IAQ) and building energy use. This paper characterizes ACRs and interzonal flows in 126 houses, and evaluates effects of these parameters on IAQ. ACRs measured using weeklong tracer measurements in several seasons averaged 0.73 ± 0.76 h(-1) (median = 0.57 h(-1), n = 263) in the general living area, and much higher, 1.66 ± 1.50 h(-1) (median = 1.23 h(-1), n = 253) in bedrooms. Living area ACRs were highest in winter and lowest in spring; bedroom ACRs were highest in summer and lowest in spring. Bedrooms received an average of 55 ± 18% of air from elsewhere in the house; the living area received only 26 ± 20% from the bedroom. Interzonal flows did not depend on season, indoor smoking or the presence of air conditioners. A two-zone IAQ model calibrated for the field study showed large differences in pollutant levels between the living area and bedroom, and the key parameters affecting IAQ were emission rates, emission source locations, air filter use, ACRs, interzonal flows, outdoor concentrations, and PM penetration factors. The single-zone models that are commonly used for residences have substantial limitations and may inadequately represent pollutant concentrations and exposures in bedrooms and potentially other environments other where people spend a substantial fraction of time.

  3. Acrolein-Induced Increases in Blood Pressure and Heart Rate Are Coupled with Decreased Blood Oxygen Levels During Exposure in Hypertensive Rats

    EPA Science Inventory

    Exposure to air pollution increases the risk of cardiovascular morbidity and mortality, especially in individuals with pre-existing cardiovascular disease. Recent studies link exposure to air pollution with reduced blood oxygen saturation suggesting that hypoxia is a potential me...

  4. Modeling Spatial and Temporal Variability of Residential Air Exchange Rates for the Near-Road Exposures and Effects of Urban Air Pollutants Study (NEXUS)

    EPA Science Inventory

    Air pollution health studies often use outdoor concentrations as exposure surrogates. Failure to account for variability of residential infiltration of outdoor pollutants can induce exposure errors and lead to bias and incorrect confidence intervals in health effect estimates. Th...

  5. Transient receptor potential cation channel A1 (TRPA1) mediates changes in heart rate variability following a single exposure to acrolein in mice

    EPA Science Inventory

    The data show that a single exposure to acrolein causes autonomic imbalance in mice through the TRPA1 sensor and subsequent cardiac dysfunction. Human and animal studies have shown that short-term air pollution exposure causes...

  6. The relationship between specific absorption rate and temperature elevation in anatomically based human body models for plane wave exposure from 30 MHz to 6 GHz.

    PubMed

    Hirata, Akimasa; Laakso, Ilkka; Oizumi, Takuya; Hanatani, Ryuto; Chan, Kwok Hung; Wiart, Joe

    2013-02-21

    According to the international safety guidelines/standard, the whole-body-averaged specific absorption rate (Poljak et al 2003 IEEE Trans. Electromagn. Compat. 45 141-5) and the peak spatial average SAR are used as metrics for human protection from whole-body and localized exposures, respectively. The IEEE standard (IEEE 2006 IEEE C95.1) indicates that the upper boundary frequency, over which the whole-body-averaged SAR is deemed to be the basic restriction, has been reduced from 6 to 3 GHz, because radio-wave energy is absorbed around the body surface when the frequency is increased. However, no quantitative discussion has been provided to support this description especially from the standpoint of temperature elevation. It is of interest to investigate the maximum temperature elevation in addition to the core temperature even for a whole-body exposure. In the present study, using anatomically based human models, we computed the SAR and the temperature elevation for a plane-wave exposure from 30 MHz to 6 GHz, taking into account the thermoregulatory response. As the primary result, we found that the ratio of the core temperature elevation to the whole-body-averaged SAR is almost frequency independent for frequencies below a few gigahertz; the ratio decreases above this frequency. At frequencies higher than a few gigahertz, core temperature elevation for the same whole-body averaged SAR becomes lower due to heat convection from the skin to air. This lower core temperature elevation is attributable to skin temperature elevation caused by the power absorption around the body surface. Then, core temperature elevation even for whole-body averaged SAR of 4 W kg(-1) with the duration of 1 h was at most 0.8 °C, which is smaller than a threshold considered in the safety guidelines/standard. Further, the peak 10 g averaged SAR is correlated with the maximum body temperature elevations without extremities and pinna over the frequencies considered. These findings

  7. Are radiosensitivity data derived from natural field conditions consistent with data from controlled exposures? A case study of Chernobyl wildlife chronically exposed to low dose rates.

    PubMed

    Garnier-Laplace, J; Geras'kin, S; Della-Vedova, C; Beaugelin-Seiller, K; Hinton, T G; Real, A; Oudalova, A

    2013-07-01

    The discrepancy between laboratory or controlled conditions ecotoxicity tests and field data on wildlife chronically exposed to ionising radiation is presented for the first time. We reviewed the available chronic radiotoxicity data acquired in contaminated fields and used a statistical methodology to support the comparison with knowledge on inter-species variation of sensitivity to controlled external γ irradiation. We focus on the Chernobyl Exclusion Zone and effects data on terrestrial wildlife reported in the literature corresponding to chronic dose rate exposure situations (from background ~100 nGy/h up to ~10 mGy/h). When needed, we reconstructed the dose rate to organisms and obtained consistent unbiased data sets necessary to establish the dose rate-effect relationship for a number of different species and endpoints. Then, we compared the range of variation of radiosensitivity of species from the Chernobyl-Exclusion Zone with the statistical distribution established for terrestrial species chronically exposed to purely gamma external irradiation (or chronic Species radioSensitivity Distribution - SSD). We found that the best estimate of the median value (HDR50) of the distribution established for field conditions at Chernobyl (about 100 μGy/h) was eight times lower than the one from controlled experiments (about 850 μGy/h), suggesting that organisms in their natural environmental were more sensitive to radiation. This first comparison highlights the lack of mechanistic understanding and the potential confusion coming from sampling strategies in the field. To confirm the apparent higher sensitive of wildlife in the Chernobyl Exclusion Zone, we call for more a robust strategy in field, with adequate design to deal with confounding factors.

  8. Comparison of L-[1-11C]methionine and L-methyl-[11C]methionine for measuring in vivo protein synthesis rates with PET.

    PubMed

    Ishiwata, K; Vaalburg, W; Elsinga, P H; Paans, A M; Woldring, M G

    1988-08-01

    To evaluate the feasibility of using either L-[1-11C]-methionine or L-[methyl-11C]methionine for measuring protein synthesis rates by positron emission tomography (PET) in normal and neoplastic tissues, distribution and metabolic studies with 14C- and 11C-labeled methionines were carried out in rats bearing Walker 256 carcinosarcoma. The tissue distributions of the two 14C-labeled methionines were similar except for liver tissue. Similar distribution patterns were observed in vivo by PET using 11C-labeled methionines. The highest 14C incorporation rate into the protein-bound fraction was found in the liver followed by tumor, brain, and pancreas. The incorporation rates in liver and pancreas were different for the two methionines. By chloroform-methanol fractionation of these four tissues, in liver significantly different amounts of 14C were observed in macromolecules. Also in brain tissue slight differences were found. By HPLC analyses of the protein-free fractions of plasma, tumor, and brain tissue at 60 min after injection, for both methionines several 14C-labeled metabolites in different amounts, were detected. About half of the 14C-labeled material in the protein-free fraction was found to be methionine. In these three tissues the amount of nonprotein metabolites and [14C]bicarbonate amount ranged from 10% to 17% and 12% to 15% for L-[1-14C]methionine and L-[methyl-14C]methionine, respectively. From these results it can be concluded that the minor metabolic pathways have to be investigated in order to quantitatively model the protein synthesis by PET.

  9. Carbon gel assisted low temperature liquid-phase synthesis of C-LiFePO4/graphene layers with high rate and cycle performances

    NASA Astrophysics Data System (ADS)

    Tang, Hongwei; Si, Yanli; Chang, Kun; Fu, Xiaoning; li, Bao; Shangguan, Enbo; Chang, Zhaorong; Yuan, Xiao-Zi; Wang, Haijiang

    2015-11-01

    Nano-scale LiFePO4/graphene oxide (GO) as cathode materials for lithium ion batteries has been successfully synthesized via a one-step carbon gel assisted liquid-phase approach at a low-temperature (108 °C) and normal pressure. C-LiFePO4/graphene layers (G) composites, composed of LiFePO4, amorphous carbon and graphene layers, are then produced after rapid high temperature carbon treatment. Interface tunnel effect, produced by the intimate contact of LiFePO4 particles with amorphous carbon and graphene layers, greatly improves the properties of the composites. Electrochemical tests indicate that the optimal amount of GO addition is 1 wt.% in terms of achieving a high electrochemical performance of the C-LiFePO4/G composites. Discharge capacity of the C-LiFePO4/G composites is 160.0 mAh g-1 at 0.2 C. When the current rate is further increased to 60 C, the discharge capacity of C-LiFePO4/G can reach 68 mAh g-1. At a high current rate of 20 C, the capacity attenuation rate of the C-LiFePO4/G electrode is only 9.6% after 200 cycles, showing excellent high-rate discharge capability and cycle performance. This is achieved under a facile synthesis condition of a simple procedure, low temperature, and normal pressure.

  10. Biomineralization-inspired synthesis of chitosan/hydroxyapatite biocomposites based on a novel bilayer rate-controlling model.

    PubMed

    Hu, Jing-Xiao; Ran, Jia-Bing; Chen, Si; Shen, Xin-Yu; Tong, Hua

    2015-12-01

    In order to prepare sophisticated biomaterials using a biomimetic approach, a deeper understanding of biomineralization is needed. Of particular importance is the control and regulation of the mineralization process. In this study, a novel bilayer rate-controlling model was designed to investigate the factors potentially influencing mineralization. In the absence of a rate-controlling layer, nano-scale hydroxyapatite (HA) crystallites exhibited a spherical morphology, whereas, in the presence of a rate-controlling layer, HA crystallites were homogeneously dispersed and spindle-like in structure. The mineralization rate had a significant effect on controlling the morphology of crystals. Furthermore, in vitro tests demonstrated that the reaction layer containing spindle-like HA crystallites possessed superior biological properties. These results suggest that a slow mineralization rate is required for controlling the morphology of inorganic crystallites, and consumption by the rate-controlling layer ensured that the ammonia concentration remained low. This study demonstrates that a biomimetic approach can be used to prepare novel biomaterials containing HA crystallites that have different morphologies and biological properties.

  11. Centrophenoxine increases the rates of total and mRNA synthesis in the brain cortex of old rats: an explanation of its action in terms of the membrane hypothesis of aging.

    PubMed

    Zs-Nagy, I; Semsei, I

    1984-01-01

    The rates of total and polyA+ RNA (mRNA) synthesis were measured by radioisotope technique in the brain cortex of female CFY rats. There was practically no significant difference between the young (1.5 months) and adult (13 months) rats; however, the old group (26 months) displayed a considerable decrease of the rates of synthesis of both classes of RNA studied. Centrophenoxine treatment (100 mg per kg body weight per day, for 2 months) reversed this tendency, and increased significantly the synthesis rates of old rats almost to the adult level. The results are interpreted in terms of the membrane hypothesis of aging, attributing a free-radical scavenger function of the dimethylamino-ethanol incorporated into the nerve cell membrane from the centrophenoxine.

  12. Preliminary Vertical Slip Rate for the West Tahoe Fault from six new Cosmogenic 10Be Exposure Ages of Late Pleistocene Glacial Moraines at Cascade Lake, Lake Tahoe, California

    NASA Astrophysics Data System (ADS)

    Pierce, I. K. D.; Wesnousky, S. G.; Kent, G. M.; Owen, L. A.

    2015-12-01

    The West Tahoe Fault is the primary range bounding fault of the Sierra Nevada at the latitude of Lake Tahoe. It is a N-NW striking, east dipping normal fault that has a pronounced onshore quaternary scarp extending from highway 50 southwest of Meyers, CA to Emerald Bay. At Cascade Lake, the fault cuts and progressively offsets late Pleistocene right lateral moraines. The fault vertically offsets the previously mapped Tahoe moraine ~83 m and the Tioga moraine ~23 m, measured from lidar data. Seventeen samples were collected for 10Be cosmogenic age analysis from boulders on both the hanging and footwalls of the fault along the crests of these moraines.We report here the initial analysis of 6 of these boulders and currently await processing of the remainder. The 10Be exposure ages of 3 boulders each on the younger Tioga and older Tahoe moraines range from 12.7 +/- 1.6 to 20.7 +/- 3.3 ka and 13.3 +/- 2.1 to 72.5 +/- 8.8 ka, respectively. Using the oldest ages as minima, these preliminary results suggest that the slip rate has averaged ~1 mm/yr since the penultimate glaciation, in accord with estimates of previous workers, and place additional bounds on the age of glaciation in the Lake Tahoe basin. The Last Glacial Maxima and penultimate glaciation near Lake Tahoe thus appear to coincide with the Tioga and Tahoe II glaciations of the Eastern Sierra.

  13. The determination of short-term breast volume changes and the rate of synthesis of human milk using computerized breast measurement.

    PubMed

    Daly, S E; Kent, J C; Huynh, D Q; Owens, R A; Alexander, B F; Ng, K C; Hartmann, P E

    1992-01-01

    The feasibility of using sequential breast volume measurements as a method of studying short-term rates of milk synthesis in women has been established. We have developed a rapid Computerized Breast Measurement system for the determination of breast volume, based upon the Shape Measurement System. A circle encompassing all the breast tissue is drawn in black face paint on the subject's skin. Six patterns of sixty-four horizontal light stripes are projected onto the breast and chest wall surface. A CCD camera relays video images to a computer, which produces a model of the chest by active triangulation. The volume of the breast and the chest wall segment enclosed by the circle is then calculated. The precision of the method was dependent upon the subject repositioning carefully. The coefficient of variation of replicate measurements was 1.6%. The accuracy of the method was established by comparing the change in breast volume before and after a breast-feed with the amount of milk removed by the infant as determined by test weighing. There was a close relationship between the removal of milk by the infant (x) and the change in breast volume (y), (r = 0.93, n = 73, y = 1.10x - 3.25). The rates of milk synthesis between breast-feeds, for six women determined on one to eight occasions, varied from 11 to 58 ml/h. The results show that the amount of milk available in the breast is not necessarily an important determinant of the amount of milk removed by the infant at a breast-feed. PMID:1543594

  14. Schwertmannite Synthesis through Ferrous Ion Chemical Oxidation under Different H2O2 Supply Rates and Its Removal Efficiency for Arsenic from Contaminated Groundwater

    PubMed Central

    Zhang, Shasha; Liu, Lanlan; Zhou, Lixiang; Fan, Wenhua

    2015-01-01

    Schwertmannite-mediated removal of arsenic from contaminated water has attracted increasing attention. However, schwertmannite chemical synthesis behavior under different H2O2 supply rates for ferrous ions oxidation is unclear. This study investigated pH, ferrous ions oxidation efficiency, and total iron precipitation efficiency during schwertmannite synthesis by adding H2O2 into FeSO4·7H2O solution at different supply rates. Specific surface area and arsenic (III) removal capacity of schwertmannite have also been studied. Results showed that pH decreased from ~3.48 to ~1.96, ~2.06, ~2.12, ~2.14, or ~2.17 after 60 h reaction when the ferrous ions solution received the following corresponding amounts of H2O2: 1.80 mL at 2 h (treatment 1); 0.90 mL at 2 h and 14 h (treatment 2); 0.60 mL at 2, 14, and 26 h (treatment 3); 0.45 mL at 2, 14, 26, and 38 h (treatment 4), or 0.36 mL at 2, 14, 26, 38, and 50 h (treatment 5). Slow H2O2 supply significantly inhibited the total iron precipitation efficiency but improved the specific surface area or arsenic (III) removal capacity of schwertmannite. For the initial 50.0 μg/L arsenic (III)-contaminated water under pH ~7.0 and using 0.25 g/L schwertmannite as an adsorbent, the total iron precipitation efficiency, specific surface area of the harvested schwertmannite, and schwertmannite arsenic(III) removal efficiency were 29.3%, 2.06 m2/g, and 81.1%, respectively, in treatment 1. However, the above parameters correspondingly changed to 17.3%, 16.30 m2/g, and 96.5%, respectively, in treatment 5. PMID:26398214

  15. Synthesis of three-dimensionally interconnected sulfur-rich polymers for cathode materials of high-rate lithium–sulfur batteries

    PubMed Central

    Kim, Hoon; Lee, Joungphil; Ahn, Hyungmin; Kim, Onnuri; Park, Moon Jeong

    2015-01-01

    Elemental sulfur is one of the most attractive cathode active materials in lithium batteries because of its high theoretical specific capacity. Despite the positive aspect, lithium–sulfur batteries have suffered from severe capacity fading and limited rate capability. Here we report facile large-scale synthesis of a class of organosulfur compounds that could open a new chapter in designing cathode materials to advance lithium–sulfur battery technologies. Porous trithiocyanuric acid crystals are synthesized for use as a soft template, where the ring-opening polymerization of elemental sulfur takes place along the thiol surfaces to create three-dimensionally interconnected sulfur-rich phases. Our lithium–sulfur cells display discharge capacity of 945 mAh g−1 after 100 cycles at 0.2 C with high-capacity retention of 92%, as well as lifetimes of 450 cycles. Particularly, the organized amine groups in the crystals increase Li+-ion transfer rate, affording a rate performance of 1210, mAh g−1 at 0.1 C and 730 mAh g−1 at 5 C. PMID:26065407

  16. Very low frequency oscillations in the power spectra of heart rate variability during dry supine immersion and exposure to non-hypoxic hypobaria.

    PubMed

    Tripathi, K K

    2011-06-01

    The origin of very low frequency (VLF) oscillations in the power spectra of heart rate variability (HRV) is controversial with possible mechanisms involving thermoregulation and/or renin-angiotensin-aldosterone system. Recently, a major contribution from vagal influences has been suggested. The present study investigated the behaviour of VLF (0.004-0.040 Hz) components of HRV power spectra in a group of healthy male volunteers during their exposure to (1) dry, supine, immersion in thermo-neutral water for 6 h (n = 7) and (2) non-hypoxic hypobaria (breathing 40-60% oxygen at 15,000' simulated in a decompression chamber) for 5 h (n = 15). The two manoeuvres are established to increase vagal outflow. During both the manoeuvres, all the frequency domain indices of HRV exhibited a significant increase. Increase in HRV was much more than that in the R-R interval. At 6 h of immersion, the R-R interval increased by ∼ 15% but the total power increased ∼ fourfold. Similarly, at 5 h of exposure to hypobaria, total power increased ∼ twofold with a very modest increase in an R-R of ∼ 9%. Increase in spectral power was appreciable even after normalization with mean R-R(2). Increase in VLF during immersion was more than reported during enalaprilat blockade of angiotensin convertase enzyme. Plasma renin activity did not vary during hypobaria. There was a significant increase in pNN50, an established marker of cardiac vagal activity. Centre frequencies of the spectra and slope (β) of the relation between log(PSD) and log(frequency) did not change. Results were supportive of the notion that the parasympathetic system is pre-potent to influence slower (than respiratory) frequency components in HRV spectrum. Additionally, such an effect was without a change in the time constant of effector responses or pacemaker frequencies of VLF and LF periodicities and HRV was not a simple linear surrogate for cardiac vagal effects. An invariance of spectral exponent (β) ruled out

  17. Phospholipid Synthesis in Sindbis Virus-Infected Cells

    PubMed Central

    Waite, Marilynn R. F.; Pfefferkorn, E. R.

    1970-01-01

    We investigated the metabolic requirements for the decrease in phospholipid synthesis previously observed by Pfefferkorn and Hunter in primary cultures of chick embryo fibroblasts infected with Sindbis virus. The incorporation of 32PO4 into all classes of phospholipids was found to decline at the same rate and to the same extent; thus, incorporation of 14C-choline into acid-precipitable form provided a convenient measure of phospholipid synthesis that was used in subsequent experiments. Experiments with temperature-sensitive mutants suggested that some viral ribonucleic acid (RNA) synthesis was essential for the inhibition of choline incorporation, but that functional viral structural proteins were not required. The reduction in phospholipid synthesis was probably a secondary effect of infection resulting from viral inhibition of the cellular RNA and protein synthesis. All three inhibitory effects required about the same amount of viral RNA synthesis; the inhibition of host RNA and protein synthesis began sooner than the decline in phospholipid synthesis; and both actinomycin D and cycloheximide inhibited 14C-choline incorporation in uninfected cells. In contrast, incorporation of 14C-choline into BHK-21 cells was not decreased by 10 hr of exposure to actinomycin D and declined only slowly after cycloheximide treatment. Growth of Sindbis virus in BHK cells did not cause the marked stimulation of phospholipid synthesis seen in picornavirus infections of other mammalian cells; however, inhibition was seen only late in infection. PMID:5530011

  18. Influence of Human Activity Patterns, particle composition, and residential air exchange rates on modeled distributions of PM 2.5 exposure compared with central-site monitoring data

    EPA Science Inventory

    Central-site monitors do not account for factors such as outdoor-to-indoor transport and human activity patterns that influence personal exposures to ambient fine-particulate matter (PM2.5). We describe and compare different ambient PM2.5 exposure estimation...

  19. The Influence of Exposure to Maternal Diabetes In Utero on the Rate Of Decline in Beta-Cell Function Among Youth with Diabetes

    PubMed Central

    Crume, T.L.; Andrews, J.S.; D’Agostino, R.; Pettitt, D.J.; Mayer-Davis, E.J.; Law, J.R.; Dolan, L.; Lawrence, J.M.; Saydah, S.; Greenbaum, C.; Rodriguez, B.L.; Dabelea, D.

    2014-01-01

    A relationship between exposure to maternal diabetes in utero and a younger age at diagnosis of type 2 diabetes was detected in SEARCH for Diabetes in Youth Study, while no significant association was detected with paternal diabetes status, suggesting an independent effect of the intrauterine exposure to hyperglycemia. We assessed the influence of exposure to maternal diabetes in utero on beta cell decline measured using fasting C-peptide (FCP) among 1079 youth with diabetes, including 941 with type 1 and 138 with type 2, who were followed post-diagnosis for an average of 58 months. No significant relationship was detected between exposure to maternal diabetes in utero and change in FCP levels in youth with type 1 or type 2 diabetes. These findings suggest that exposure to maternal diabetes in utero may not be an important determinant of short-term beta-cell function decline in youth with type 1 or type 2 diabetes. PMID:23645121

  20. Cell proliferation rate and tumor volume in human osteosarcoma during exposure to methotrexate. A study on tissue transplants in nude mice.

    PubMed

    Smeds, S; Walz, T; Blomquist, L; Larsson, S E

    1991-10-01

    The growth inhibitory effect of methotrexate (MTX) on osteosarcoma cells was studied in dysthymic nude mice bearing tumor transplants obtained from a patient before (PRE-CHEM) and after (POST-CHEM) preoperative chemotherapy for osteosarcoma of the distal femur. Cell proliferation was analyzed by autoradiographic evaluation of the fraction of labeled cells after continuous administration of 3H-thymidine for seven days. Histomorphometric analysis of the tissue distribution of cells in the partly ossified tumors was performed. The PRE-CHEM sarcoma transplants showed a significant reduction of labeled interphases from 52 to 1.7 percent upon daily MTX treatment of the mice as compared to controls. In contrast, MTX treatment did not inhibit cell proliferation in the POST-CHEM tumor transplants in which approximately 70 percent of the cells were labeled. Tumor volume increased by 65 and 54 percent in the MTX-treated PRE- and POST-CHEM groups, respectively. During the same eight-day period, control transplant volume increased by 30 percent (PRE-CHEM) and 20 percent (POST-CHEM). Tumor cell densities in the MTX-treated groups were reduced by a factor of approximately 11 in the PRE-CHEM transplants and by a factor of approximately 1.5 in the POST-CHEM transplants. The results show that in this patient the osteosarcoma cells had changed their responsiveness to MTX during the preoperative chemotherapy period. In both the MTX-sensitive and non-sensitive tumor lines, exposure to MTX induced increased tumor volume by increasing the extra cellular matrix volume, irrespective of the neoplastic cell proliferation rate. This effect of MTX was most pronounced in the MTX-sensitive tumor line. These results indicate that in the clinical situation it is difficult to judge the response to chemotherapy even from morphologic parameters.

  1. Targeting pre-exposure prophylaxis among men who have sex with men in the United States and Peru: partnership types, contact rates, and sexual role

    PubMed Central

    Carnegie, Nicole Bohme; Goodreau, Steven M.; Liu, Albert; Vittinghoff, Eric; Sanchez, Jorge; Lama, Javier R.; Buchbinder, Susan

    2015-01-01

    Background We aim to identify optimal strategies for deploying pre-exposure prophylaxis among men who have sex with men in the US and Peru to maximize population-level effectiveness in an efficient manner. We use epidemic models to simulate the impact of targeting strategies. Most studies have focused on targeting either the general population or high-risk MSM. Alternative strategies, including serodiscordant couples, may better balance effectiveness and efficiency. Methods We use dynamic, stochastic sexual network models based in exponential-family random graph modeling, parameterized from behavioral surveys of MSM in the US and Peru. These models represent main partnerships and casual contacts separately, permitting modeling of interventions targeting men whose risk derives from combinations of relational types. We also model varying rates of uptake and adherence to PrEP. We assess sensitivity of results to risk compensation via increases in condomless casual contacts and condomless sex in main partnerships. Results Targeting all men who are not exclusively insertive has the largest impact on HIV incidence, but targeting only those with high levels of casual activity yields comparable results using fewer person-years on PrEP. The effect is robust to risk compensation in the US, but less so in Peru. Targeting serodiscordant main partnerships does not significantly impact incidence, but requires fewer person-years on PrEP per infection averted than other strategies. Conclusions PrEP could be effective in reducing new infections at the population level in both settings. Serodiscordant partnerships are an attractive component of a targeting program, but targeting should include other high-risk men. PMID:25942463

  2. Exposure to a specific pulsed low-frequency magnetic field: A double-blind placebo-controlled study of effects on pain ratings in rheumatoid arthritis and fibromyalgia patients

    PubMed Central

    Shupak, Naomi M; McKay, Julia C; Nielson, Warren R; Rollman, Gary B; Prato, Frank S; Thomas, Alex W

    2006-01-01

    BACKGROUND Specific pulsed electromagnetic fields (PEMFs) have been shown to induce analgesia (antinociception) in snails, rodents and healthy human volunteers. OBJECTIVE The effect of specific PEMF exposure on pain and anxiety ratings was investigated in two patient populations. DESIGN A double-blind, randomized, placebo-controlled parallel design was used. METHOD The present study investigated the effects of an acute 30 min magnetic field exposure (less than or equal to 400 μTpk; less than 3 kHz) on pain (McGill Pain Questionnaire [MPQ], visual analogue scale [VAS]) and anxiety (VAS) ratings in female rheumatoid arthritis (RA) (n=13; mean age 52 years) and fibromyalgia (FM) patients (n=18; mean age 51 years) who received either the PEMF or sham exposure treatment. RESULTS A repeated measures analysis revealed a significant pre-post-testing by condition interaction for the MPQ Pain Rating Index total for the RA patients, F(1,11)=5.09, P<0.05, estimate of effect size = 0.32, power = 0.54. A significant pre-post-effect for the same variable was present for the FM patients, F(1,15=16.2, P<0.01, estimate of effect size = 0.52, power =0.96. Similar findings were found for MPQ subcomponents and the VAS (pain). There was no significant reduction in VAS anxiety ratings pre- to post-exposure for either the RA or FM patients. CONCLUSION These findings provide some initial support for the use of PEMF exposure in reducing pain in chronic pain populations and warrants continued investigation into the use of PEMF exposure for short-term pain relief. PMID:16770449

  3. Sugar-induced increases in trehalose 6-phosphate are correlated with redox activation of ADPglucose pyrophosphorylase and higher rates of starch synthesis in Arabidopsis thaliana.

    PubMed

    Lunn, John E; Feil, Regina; Hendriks, Janneke H M; Gibon, Yves; Morcuende, Rosa; Osuna, Daniel; Scheible, Wolf-Rüdiger; Carillo, Petronia; Hajirezaei, Mohammad-Reza; Stitt, Mark

    2006-07-01

    Tre6P (trehalose 6-phosphate) is implicated in sugar-signalling pathways in plants, but its exact functions in vivo are uncertain. One of the main obstacles to discovering these functions is the difficulty of measuring the amount of Tre6P in plant tissues. We have developed a highly specific assay, using liquid chromatography coupled to MS-Q3 (triple quadrupole MS), to measure Tre6P in the femto-picomole range. The Tre6P content of sucrose-starved Arabidopsis thaliana seedlings in axenic culture increased from 18 to 482 pmol x g(-1) FW (fresh weight) after adding sucrose. Leaves from soil-grown plants contained 67 pmol x g(-1) FW at the end of the night, which rose to 108 pmol x g(-1)FW after 4 h of illumination. Even greater changes in Tre6P content were seen after a 6 h extension of the dark period, and in the starchless mutant, pgm. The intracellular concentration of Tre6P in wild-type leaves was estimated to range from 1 to 15 microM. It has recently been reported that the addition of Tre6P to isolated chloroplasts leads to redox activation of AGPase (ADPglucose pyrophosphorylase) [Kolbe, Tiessen, Schluepmann, Paul, Ulrich and Geigenberger (2005) Proc. Natl. Acad. Sci. U.S.A. 102, 11118-11123]. Using the new assay for Tre6P, we found that rising sugar levels in plants are accompanied by increases in the level of Tre6P, redox activation of AGPase and the stimulation of starch synthesis in vivo. These results indicate that Tre6P acts as a signalling metabolite of sugar status in plants, and support the proposal that Tre6P mediates sucrose-induced changes in the rate of starch synthesis.

  4. Sugar-induced increases in trehalose 6-phosphate are correlated with redox activation of ADPglucose pyrophosphorylase and higher rates of starch synthesis in Arabidopsis thaliana

    PubMed Central

    Lunn, John E.; Feil, Regina; Hendriks, Janneke H. M.; Gibon, Yves; Morcuende, Rosa; Osuna, Daniel; Scheible, Wolf-Rüdiger; Carillo, Petronia; Hajirezaei, Mohammad-Reza; Stitt, Mark

    2006-01-01

    Tre6P (trehalose 6-phosphate) is implicated in sugar-signalling pathways in plants, but its exact functions in vivo are uncertain. One of the main obstacles to discovering these functions is the difficulty of measuring the amount of Tre6P in plant tissues. We have developed a highly specific assay, using liquid chromatography coupled to MS-Q3 (triple quadrupole MS), to measure Tre6P in the femto-picomole range. The Tre6P content of sucrose-starved Arabidopsis thaliana seedlings in axenic culture increased from 18 to 482 pmol·g−1FW (fresh weight) after adding sucrose. Leaves from soil-grown plants contained 67 pmol·g−1FW at the end of the night, which rose to 108 pmol·g−1FW after 4 h of illumination. Even greater changes in Tre6P content were seen after a 6 h extension of the dark period, and in the starchless mutant, pgm. The intracellular concentration of Tre6P in wild-type leaves was estimated to range from 1 to 15 μM. It has recently been reported that the addition of Tre6P to isolated chloroplasts leads to redox activation of AGPase (ADPglucose pyrophosphorylase) [Kolbe, Tiessen, Schluepmann, Paul, Ulrich and Geigenberger (2005) Proc. Natl. Acad. Sci. U.S.A. 102, 11118–11123]. Using the new assay for Tre6P, we found that rising sugar levels in plants are accompanied by increases in the level of Tre6P, redox activation of AGPase and the stimulation of starch synthesis in vivo. These results indicate that Tre6P acts as a signalling metabolite of sugar status in plants, and support the proposal that Tre6P mediates sucrose-induced changes in the rate of starch synthesis. PMID:16551270

  5. Amino Acid Synthesis in Photosynthesizing Spinach Cells: Effects of Ammonia on Pool Sizes and Rates of Labeling from 14CO2

    SciTech Connect

    Larsen, Peder Olesen; Cornwell, Karen L.; Gee, Sherry L.; Bassham, James A.

    1981-08-01

    In this paper, isolated cells from leaves of Spinacia oleracea have been maintained in a state capable of high rates of photosynthetic CO2 fixation for more than 60 hours. The incorporation of 14CO2 under saturating CO2 conditions into carbohydrates, carboxylic acids, and amino acids, and the effect of ammonia on this incorporation have been studied. Total incorporation, specific radioactivity, and pool size have been determined as a function of time for most of the protein amino acids and for γ-aminobutyric acid. The measurements of specific radio-activities and of the approaches to 14C “saturation” of some amino acids indicate the presence and relative sizes of metabolically active and passive pools of these amino acids. Added ammonia decreased carbon fixation into carbohydrates and increased fixation into carboxylic acids and amino acids. Different amino acids were, however, affected in different and highly specific ways. Ammonia caused large stimulatory effects in incorporation of 14C into glutamine (a factor of 21), aspartate, asparagine, valine, alanine, arginine, and histidine. No effect or slight decreases were seen in glycine, serine, phenylalanine, and tyrosine labeling. In the case of glutamate, 14C labeling decreased, but specific radioactivity increased. The production of labeled γ-aminobutyric acid was virtually stopped by ammonia. The results indicate that added ammonia stimulates the reactions mediated by pyruvate kinase and phosphoenolpyruvate carboxylase, as seen with other plant systems. Finally, the data on the effects of added ammonia on total labeling, pool sizes, and specific radioactivities of several amino acids provides a number of indications about the intracellular sites of principal synthesis from carbon skeletons of these amino acids and the selective nature of effects of increased intracellular ammonia concentration on such synthesis.

  6. Exposure of ELF-EMF and RF-EMF Increase the Rate of Glucose Transport and TCA Cycle in Budding Yeast

    PubMed Central

    Lin, Kang-Wei; Yang, Chuan-Jun; Lian, Hui-Yong; Cai, Peng

    2016-01-01

    In this study, we investigated the transcriptional response to 50 Hz extremely low frequency electromagnetic field (ELF-EMF) and 2.0 GHz radio frequency electromagnetic field (RF-EMF) exposure by Illumina sequencing technology using budding yeast as the model organism. The transcription levels of 28 genes were upregulated and those of four genes were downregulated under ELF-EMF exposure, while the transcription levels of 29 genes were upregulated and those of 24 genes were downregulated under RF-EMF exposure. After validation by reverse transcription quantitative polymerase chain reaction (RT-qPCR), a concordant direction of change both in differential gene expression (DGE) and RT-qPCR was demonstrated for nine genes under ELF-EMF exposure and for 10 genes under RF-EMF exposure. The RT-qPCR results revealed that ELF-EMF and RF-EMF exposure can upregulate the expression of genes involved in glucose transportation and the tricarboxylic acid (TCA) cycle, but not the glycolysis pathway. Energy metabolism is closely related with the cell response to environmental stress including EMF exposure. Our findings may throw light on the mechanism underlying the biological effects of EMF. PMID:27630630

  7. Exposure of ELF-EMF and RF-EMF Increase the Rate of Glucose Transport and TCA Cycle in Budding Yeast.

    PubMed

    Lin, Kang-Wei; Yang, Chuan-Jun; Lian, Hui-Yong; Cai, Peng

    2016-01-01

    In this study, we investigated the transcriptional response to 50 Hz extremely low frequency electromagnetic field (ELF-EMF) and 2.0 GHz radio frequency electromagnetic field (RF-EMF) exposure by Illumina sequencing technology using budding yeast as the model organism. The transcription levels of 28 genes were upregulated and those of four genes were downregulated under ELF-EMF exposure, while the transcription levels of 29 genes were upregulated and those of 24 genes were downregulated under RF-EMF exposure. After validation by reverse transcription quantitative polymerase chain reaction (RT-qPCR), a concordant direction of change both in differential gene expression (DGE) and RT-qPCR was demonstrated for nine genes under ELF-EMF exposure and for 10 genes under RF-EMF exposure. The RT-qPCR results revealed that ELF-EMF and RF-EMF exposure can upregulate the expression of genes involved in glucose transportation and the tricarboxylic acid (TCA) cycle, but not the glycolysis pathway. Energy metabolism is closely related with the cell response to environmental stress including EMF exposure. Our findings may throw light on the mechanism underlying the biological effects of EMF. PMID:27630630

  8. Exposure of ELF-EMF and RF-EMF Increase the Rate of Glucose Transport and TCA Cycle in Budding Yeast

    PubMed Central

    Lin, Kang-Wei; Yang, Chuan-Jun; Lian, Hui-Yong; Cai, Peng

    2016-01-01

    In this study, we investigated the transcriptional response to 50 Hz extremely low frequency electromagnetic field (ELF-EMF) and 2.0 GHz radio frequency electromagnetic field (RF-EMF) exposure by Illumina sequencing technology using budding yeast as the model organism. The transcription levels of 28 genes were upregulated and those of four genes were downregulated under ELF-EMF exposure, while the transcription levels of 29 genes were upregulated and those of 24 genes were downregulated under RF-EMF exposure. After validation by reverse transcription quantitative polymerase chain reaction (RT-qPCR), a concordant direction of change both in differential gene expression (DGE) and RT-qPCR was demonstrated for nine genes under ELF-EMF exposure and for 10 genes under RF-EMF exposure. The RT-qPCR results revealed that ELF-EMF and RF-EMF exposure can upregulate the expression of genes involved in glucose transportation and the tricarboxylic acid (TCA) cycle, but not the glycolysis pathway. Energy metabolism is closely related with the cell response to environmental stress including EMF exposure. Our findings may throw light on the mechanism underlying the biological effects of EMF.

  9. Facile synthesis of self-supported Ni2P nanosheet@Ni sponge composite for high-rate battery

    NASA Astrophysics Data System (ADS)

    Shi, F.; Xie, D.; Zhong, Y.; Wang, D. H.; Xia, X. H.; Gu, C. D.; Wang, X. L.; Tu, J. P.

    2016-10-01

    To meet the requirements for high-rate battery with desirable performance, a self-supported Ni2P@Ni sponge electrode is synthesized via simple steps, in which the Ni sponge substrate is synthesized by a one-pot hydrothermal method and the Ni2P nanosheets grown on the novel substrate are converted from Ni(OH)2 via a phosphorization reaction. This hybrid composite combines the 3D porous structure of Ni sponge and high capacity of Ni2P nanosheets, which exhibits lightweight, flexible and highly-conductive properties, resulting in an excellent specific capacity of 430.3 mAh g-1 at a current density of 1 A g-1 and remaining as high as 77.0% capacity even at 40 A g-1. More importantly, the Ni2P@Ni sponge//C cell exhibits the maximum energy density of 182.1 W h kg-1 at a power density of 205 W kg-1 along with superior capacity retention of 85.2% after 3000 cycles. It is suggested that the Ni2P nanosheet@ Ni sponge composite is a promising electrode material for high-rate batteries.

  10. Vitamin B-6 restriction tends to reduce the red blood cell glutathione synthesis rate without affecting red blood cell or plasma glutathione concentrations in healthy men and women123

    PubMed Central

    Lamers, Yvonne; O'Rourke, Bruce; Gilbert, Lesa R; Keeling, Christine; Matthews, Dwight E; Stacpoole, Peter W

    2009-01-01

    Background: Glutathione plays various protective roles in the human body. Vitamin B-6 as pyridoxal-5′-phosphate (PLP) is required as the coenzyme in the formation of glutathione precursors. Despite this obligatory role of PLP, previous studies from this laboratory showed that vitamin B-6 deficiency caused elevated glutathione concentrations in rat liver and human plasma. Objective: Our aim was to determine the effect of marginal vitamin B-6 deficiency (plasma PLP 20–30 nmol/L) on the rate of red blood cell (RBC) glutathione synthesis. Design: We measured plasma and RBC glutathione concentrations and the fractional and absolute synthesis rates of RBC glutathione using the stable-isotope-labeled glutathione precursor [1,2-13C2]glycine in 13 healthy volunteers aged 21–39 y. Results: Dietary vitamin B-6 restriction did not significantly affect the glutathione concentration in plasma (6.9 ± 1.9 compared with 6.7 ± 1.1 μmol/L) or RBCs (2068 ± 50 compared with 2117 ± 48 μmol/L). For RBC glutathione, the mean fractional synthesis rates were 54 ± 5%/d and 43 ± 4%/d (P = 0.10), and the absolute synthesis rates were 1116 ± 100 and 916 ± 92 μmol · L−1 · d−1 (P = 0.14) before and after vitamin B-6 restriction, respectively. Conclusions: Marginal vitamin B-6 deficiency tended to decrease mean RBC glutathione synthesis with no effect on RBC glutathione concentration, but the responses varied widely among individuals. Because the cysteine concentration in plasma and RBC did not change during vitamin B-6 restriction, we conclude that the effects of marginal vitamin B-6 deficiency on glutathione synthesis are not caused by altered precursor concentrations. PMID:19515736

  11. Subnuclear localization, rates and effectiveness of UVC-induced unscheduled DNA synthesis visualized by fluorescence widefield, confocal and super-resolution microscopy.

    PubMed

    Pierzyńska-Mach, Agnieszka; Szczurek, Aleksander; Cella Zanacchi, Francesca; Pennacchietti, Francesca; Drukała, Justyna; Diaspro, Alberto; Cremer, Christoph; Darzynkiewicz, Zbigniew; Dobrucki, Jurek W

    2016-01-01

    Unscheduled DNA synthesis (UDS) is the final stage of the process of repair of DNA lesions induced by UVC. We detected UDS using a DNA precursor, 5-ethynyl-2'-deoxyuridine (EdU). Using wide-field, confocal and super-resolution fluorescence microscopy and normal human fibroblasts, derived from healthy subjects, we demonstrate that the sub-nuclear pattern of UDS detected via incorporation of EdU is different from that when BrdU is used as DNA precursor. EdU incorporation occurs evenly throughout chromatin, as opposed to just a few small and large repair foci detected by BrdU. We attribute this difference to the fact that BrdU antibody is of much larger size than EdU, and its accessibility to the incorporated precursor requires the presence of denatured sections of DNA. It appears that under the standard conditions of immunocytochemical detection of BrdU only fragments of DNA of various length are being denatured. We argue that, compared with BrdU, the UDS pattern visualized by EdU constitutes a more faithful representation of sub-nuclear distribution of the final stage of nucleotide excision repair induced by UVC. Using the optimized integrated EdU detection procedure we also measured the relative amount of the DNA precursor incorporated by cells during UDS following exposure to various doses of UVC. Also described is the high degree of heterogeneity in terms of the UVC-induced EdU incorporation per cell, presumably reflecting various DNA repair efficiencies or differences in the level of endogenous dT competing with EdU within a population of normal human fibroblasts. PMID:27097376

  12. Increased Release of Mercury from Dental Amalgam Fillings due to Maternal Exposure to Electromagnetic Fields as a Possible Mechanism for the High Rates of Autism in the Offspring: Introducing a Hypothesis.

    PubMed

    Mortazavi, Gh; Haghani, M; Rastegarian, N; Zarei, S; Mortazavi, S M J

    2016-03-01

    According to the World Health Organization (WHO), factors such as growing electricity demand, ever-advancing technologies and changes in social behaviour have led to steadily increasing exposure to man-made electromagnetic fields.  Dental amalgam fillings are among the major sources of exposure to elemental mercury vapour in the general population. Although it was previously believed that low levels are mercury (i.g. release of mercury from dental amalgam) is not hazardous, now numerous data indicate that even very low doses of mercury cause toxicity. There are some evidence indicating that perinatal exposure to mercury is significantly associated with an increased risk of developmental disorders such as autism spectrum disorders (ASD) and attention-deficit hyperactivity disorder (ADHD). Furthermore, mercury can decrease the levels of neurotransmitters dopamine, serotonin, noreprenephrine, and acetylcholine in the brain and cause neurological problems. On the other hand, a strong positive correlation between maternal and cord blood mercury levels is found in some studies. We have previously shown that exposure to MRI or microwave radiation emitted by common mobile phones can lead to increased release of mercury from dental amalgam fillings. Moreover, when we investigated the effects of MRI machines with stronger magnetic fields, our previous findings were confirmed. As a strong association between exposure to electromagnetic fields and mercury level has been found in our previous studies, our findings can lead us to this conclusion that maternal exposure to electromagnetic fields in mothers with dental amalgam fillings may cause elevated levels of mercury and trigger the increase in autism rates. Further studies are needed to have a better understanding of the possible role of the increased mercury level after exposure to electromagnetic fields and the rate of autism spectrum disorders in the offspring.

  13. Increased Release of Mercury from Dental Amalgam Fillings due to Maternal Exposure to Electromagnetic Fields as a Possible Mechanism for the High Rates of Autism in the Offspring: Introducing a Hypothesis

    PubMed Central

    Mortazavi, Gh.; Haghani, M.; Rastegarian, N.; Zarei, S.; Mortazavi, S.M.J.

    2016-01-01

    According to the World Health Organization (WHO), factors such as growing electricity demand, ever-advancing technologies and changes in social behaviour have led to steadily increasing exposure to man-made electromagnetic fields.  Dental amalgam fillings are among the major sources of exposure to elemental mercury vapour in the general population. Although it was previously believed that low levels are mercury (i.g. release of mercury from dental amalgam) is not hazardous, now numerous data indicate that even very low doses of mercury cause toxicity. There are some evidence indicating that perinatal exposure to mercury is significantly associated with an increased risk of developmental disorders such as autism spectrum disorders (ASD) and attention-deficit hyperactivity disorder (ADHD). Furthermore, mercury can decrease the levels of neurotransmitters dopamine, serotonin, noreprenephrine, and acetylcholine in the brain and cause neurological problems. On the other hand, a strong positive correlation between maternal and cord blood mercury levels is found in some studies. We have previously shown that exposure to MRI or microwave radiation emitted by common mobile phones can lead to increased release of mercury from dental amalgam fillings. Moreover, when we investigated the effects of MRI machines with stronger magnetic fields, our previous findings were confirmed. As a strong association between exposure to electromagnetic fields and mercury level has been found in our previous studies, our findings can lead us to this conclusion that maternal exposure to electromagnetic fields in mothers with dental amalgam fillings may cause elevated levels of mercury and trigger the increase in autism rates. Further studies are needed to have a better understanding of the possible role of the increased mercury level after exposure to electromagnetic fields and the rate of autism spectrum disorders in the offspring. PMID:27026954

  14. Increased Release of Mercury from Dental Amalgam Fillings due to Maternal Exposure to Electromagnetic Fields as a Possible Mechanism for the High Rates of Autism in the Offspring: Introducing a Hypothesis.

    PubMed

    Mortazavi, Gh; Haghani, M; Rastegarian, N; Zarei, S; Mortazavi, S M J

    2016-03-01

    According to the World Health Organization (WHO), factors such as growing electricity demand, ever-advancing technologies and changes in social behaviour have led to steadily increasing exposure to man-made electromagnetic fields.  Dental amalgam fillings are among the major sources of exposure to elemental mercury vapour in the general population. Although it was previously believed that low levels are mercury (i.g. release of mercury from dental amalgam) is not hazardous, now numerous data indicate that even very low doses of mercury cause toxicity. There are some evidence indicating that perinatal exposure to mercury is significantly associated with an increased risk of developmental disorders such as autism spectrum disorders (ASD) and attention-deficit hyperactivity disorder (ADHD). Furthermore, mercury can decrease the levels of neurotransmitters dopamine, serotonin, noreprenephrine, and acetylcholine in the brain and cause neurological problems. On the other hand, a strong positive correlation between maternal and cord blood mercury levels is found in some studies. We have previously shown that exposure to MRI or microwave radiation emitted by common mobile phones can lead to increased release of mercury from dental amalgam fillings. Moreover, when we investigated the effects of MRI machines with stronger magnetic fields, our previous findings were confirmed. As a strong association between exposure to electromagnetic fields and mercury level has been found in our previous studies, our findings can lead us to this conclusion that maternal exposure to electromagnetic fields in mothers with dental amalgam fillings may cause elevated levels of mercury and trigger the increase in autism rates. Further studies are needed to have a better understanding of the possible role of the increased mercury level after exposure to electromagnetic fields and the rate of autism spectrum disorders in the offspring. PMID:27026954

  15. Synthesis, characterization and evaluation of CO-oxidation catalysts for high repetition rate CO2 TEA lasers

    NASA Technical Reports Server (NTRS)

    Moser, Thomas P.

    1990-01-01

    An extremely active class of noble metal catalysts supported on titania was developed and fabricated at Hughes for the recombination of oxygen (O2) and carbon monoxide (CO) in closed-cycle CO2 TEA lasers. The incipient wetness technique was used to impregnate titania and alumina pellets with precious metals including platinum and palladium. In particular, the addition of cerium (used as an oxygen storage promoter) produced an extremely active Pt/Ce/TiO2 catalyst. By comparison, the complementary Pt/Ce/ gamma-Al2O3 catalyst was considerably less active. In general, chloride-free catalyst precursors proved critical in obtaining an active catalyst while also providing uniform metal distributions throughout the support structure. Detailed characterization of the Pt/Ce/TiO2 catalyst demonstrated uniform dendritic crystal growth of the metals throughout the support. Electron spectroscopy for Chemical Analysis (ESCA) analysis was used to characterize the oxidation states of Pt, Ce and Ti. The performance of the catalysts was evaluated with an integral flow reactor system incorporating real time analysis of O2 and CO. With this system, the transient and steady-state behavior of the catalysts were evaluated. The kinetic evaluation was complemented by tests in a compact, closed-cycle Hughes CO2 TEA laser operating at a pulse repetition rate of 100 Hz with a catalyst temperature of 75 to 95 C. The Pt/Ce/TiO2 catalyst was compatible with a C(13)O(16)2 gas fill.

  16. Synthesis, characterization and evaluation of CO-oxidation catalysts for high repetition rate CO2 TEA lasers

    NASA Astrophysics Data System (ADS)

    Moser, Thomas P.

    1990-06-01

    An extremely active class of noble metal catalysts supported on titania was developed and fabricated at Hughes for the recombination of oxygen (O2) and carbon monoxide (CO) in closed-cycle CO2 TEA lasers. The incipient wetness technique was used to impregnate titania and alumina pellets with precious metals including platinum and palladium. In particular, the addition of cerium (used as an oxygen storage promoter) produced an extremely active Pt/Ce/TiO2 catalyst. By comparison, the complementary Pt/Ce/ gamma-Al2O3 catalyst was considerably less active. In general, chloride-free catalyst precursors proved critical in obtaining an active catalyst while also providing uniform metal distributions throughout the support structure. Detailed characterization of the Pt/Ce/TiO2 catalyst demonstrated uniform dendritic crystal growth of the metals throughout the support. Electron spectroscopy for Chemical Analysis (ESCA) analysis was used to characterize the oxidation states of Pt, Ce and Ti. The performance of the catalysts was evaluated with an integral flow reactor system incorporating real time analysis of O2 and CO. With this system, the transient and steady-state behavior of the catalysts were evaluated. The kinetic evaluation was complemented by tests in a compact, closed-cycle Hughes CO2 TEA laser operating at a pulse repetition rate of 100 Hz with a catalyst temperature of 75 to 95 C. The Pt/Ce/TiO2 catalyst was compatible with a C(13)O(16)2 gas fill.

  17. Lung cancer mortality between 1950 and 1987 after exposure to fractionated moderate-dose-rate ionizing radiation in the Canadian fluoroscopy cohort study and a comparison with lung cancer mortality in the atomic bomb survivors study

    SciTech Connect

    Howe, G.R.

    1995-06-01

    Current lung cancer risk estimates after exposure to low-linear energy transfer radiation such as X rays are based on studies of people exposed to such radiation at high dose rates, for example the atomic bomb survivors. Radiobiology and animal experiments suggest that risks from exposure at low to moderate dose rates, for example medical diagnostic procedures, may be overestimated by such risk models, but data for humans to examine this issue are limited. In this paper we report on lung cancer mortality between 1950 and 1987 in a cohort of 64,172 Canadian tuberculosis patients, of whom 39% were exposed to highly fractionated multiple chest fluoroscopies leading to a mean lung radiation dose of 1.02 Sv received at moderate dose rates. These data have been used to estimate the excess relative risk per sievert of lung cancer mortality, and this is compared directly to estimates derived from 75,991 atomic bomb survivors. Based on 1,178 lung cancer deaths in the fluoroscopy study, there was no evidence of any positive association between risk and dose, with the relative risk at 1 Sv being 1.00 (95% confidence interval 0.94, 1.07), which contrasts with that based on the atomic bomb survivors, 1.60 (1.27, 1.99). The difference in effect between the two studies almost certainly did not arise by chance (P = 0.0001). This study provides strong support from data for humans for a substantial fractionation/dose-rate effect for low-linear energy transfer radiation and lung cancer risk. This implies that lung cancer risk from exposures to such radiation at present-day dose rates is likely to be lower than would be predicted by current radiation risk models based on studies of high-dose-rate exposures. 25 refs., 8 tabs.

  18. Synthesis of carbon-coated LiFePO 4 nanoparticles with high rate performance in lithium secondary batteries

    NASA Astrophysics Data System (ADS)

    Konarova, Muxina; Taniguchi, Izumi

    A novel preparation technique was developed for synthesizing carbon-coated LiFePO 4 nanoparticles through a combination of spray pyrolysis (SP) with wet ball milling (WBM) followed by heat treatment. Using this technique, the preparation of carbon-coated LiFePO 4 nanoparticles was investigated for a wide range of process parameters such as ball-milling time and ball-to-powder ratio. The effect of process parameters on the physical and electrochemical properties of the LiFePO 4/C composite was then discussed through the results of X-ray diffraction (XRD) analysis, field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), the Brunauer-Emmet-Teller (BET) method and the use of an electrochemical cell of Li|1 M LiClO 4 in EC:DEC = 1:1|LiFePO 4. The carbon-coated LiFePO 4 nanoparticles were prepared at 500 °C by SP and then milled at a rotating speed of 800 rpm, a ball-to-powder ratio of 40/0.5 and a ball-milling time of 3 h in an Ar atmosphere followed by heat treatment at 600 °C for 4 h in a N 2 + 3% H 2 atmosphere. SEM observation revealed that the particle size of LiFePO 4 was significantly affected by the process parameters. Furthermore, TEM observation revealed that the LiFePO 4 nanoparticles with a geometric mean diameter of 146 nm were coated with a thin carbon layer of several nanometers by the present method. Electrochemical measurement demonstrated that cells containing carbon-coated LiFePO 4 nanoparticles could deliver markedly improved battery performance in terms of discharge capacity, cycling stability and rate capability. The cells exhibited first discharge capacities of 165 mAh g -1 at 0.1 C, 130 mAh g -1 at 5 C, 105 mAh g -1 at 20 C and 75 mAh g -1 at 60 C with no capacity fading after 100 cycles.

  19. Maintaining adequate nutrition, not probiotic administration, prevents growth stunting and maintains skeletal muscle protein synthesis rates in a piglet model of colitis.

    PubMed

    Harding, Scott V; Adegoke, Olasunkanmi A J; Fraser, Keely G; Marliss, Errol B; Chevalier, Stéphanie; Kimball, Scot R; Jefferson, Leonard S; Wykes, Linda J

    2010-03-01

    Malnutrition and cytokine-induced catabolism are pervasive in children with inflammatory bowel diseases (IBD), however, the benefits of aggressive nutrition support or of probiotics on nutrient and functional deficiencies and growth remain unclear. Piglets with dextran sulfate (DS)-induced colitis consuming a 50% macronutrient restricted diet (C-MR) were compared with those receiving probiotics (C-MRP) or adequate nutrition (C-WN) and with healthy well-nourished controls (REF). C-WN versus REF had reduced growth (-34% chest circumference and -22% snout-to-rump length gain) and a tendency toward lesser weight gain, but no differences in skeletal muscle protein fractional synthesis rates (FSR) or initiation of translation via the mTOR pathway were observed. Compared with C-WN, the C-MR and C-MRP piglets had lower weight gain, growth, and skeletal muscle FSR, and lower phosphorylated p70S6K1 with higher eIF4E*4E-BP1, indicative of reduced initiation of protein translation. Finally, plasma leucine concentrations were positively correlated with weight and phosphorylated p70S6K1, whereas negatively correlated with eIF4E*4E-BP1. In conclusion, reductions in weight gain, growth, protein turnover, skeletal muscle FSR, and initiation of protein translation with moderate macronutrient restriction in colitis are not ameliorated by probiotic supplementation. However, maintaining adequate nutrient intake during colitis preserves whole body protein metabolism, but growth remains compromised.

  20. One-Pot Synthesis of Pomegranate-Structured Fe3 O4 /Carbon Nanospheres-Doped Graphene Aerogel for High-Rate Lithium Ion Batteries.

    PubMed

    He, Dafang; Li, Lixian; Bai, Fengjuan; Zha, Chenyang; Shen, Liming; Kung, Harold H; Bao, Ningzhong

    2016-03-18

    A unique hierarchically nanostructured composite of iron oxide/carbon (Fe3O4/C) nanospheres-doped three-dimensional (3D) graphene aerogel has been fabricated by a one-pot hydrothermal strategy. In this novel nanostructured composite aerogel, uniform Fe3O4 nanocrystals (5-10 nm) are individually embedded in carbon nanospheres (ca. 50 nm) forming a pomegranate-like structure. The carbon matrix suppresses the aggregation of Fe3O4 nanocrystals, avoids direct exposure of the encapsulated Fe3O4 to the electrolyte, and buffers the volume expansion. Meanwhile, the interconnected 3D graphene aerogel further serves to reinforce the structure of the Fe3O4/C nanospheres and enhances the electrical conductivity of the overall electrode. Therefore, the carbon matrix and the interconnected graphene network entrap the Fe3O4 nanocrystals such that their electrochemical function is retained even after fracture. This novel hierarchical aerogel structure delivers a long-term stability of 634 mA h g(-1) over 1000 cycles at a high current density of 6 A g(-1) (7 C), and an excellent rate capability of 413 mA h g(-1) at 10 A g(-1) (11 C), thus exhibiting great potential as an anode composite structure for durable high-rate lithium-ion batteries. PMID:26879124

  1. One-Pot Synthesis of Pomegranate-Structured Fe3 O4 /Carbon Nanospheres-Doped Graphene Aerogel for High-Rate Lithium Ion Batteries.

    PubMed

    He, Dafang; Li, Lixian; Bai, Fengjuan; Zha, Chenyang; Shen, Liming; Kung, Harold H; Bao, Ningzhong

    2016-03-18

    A unique hierarchically nanostructured composite of iron oxide/carbon (Fe3O4/C) nanospheres-doped three-dimensional (3D) graphene aerogel has been fabricated by a one-pot hydrothermal strategy. In this novel nanostructured composite aerogel, uniform Fe3O4 nanocrystals (5-10 nm) are individually embedded in carbon nanospheres (ca. 50 nm) forming a pomegranate-like structure. The carbon matrix suppresses the aggregation of Fe3O4 nanocrystals, avoids direct exposure of the encapsulated Fe3O4 to the electrolyte, and buffers the volume expansion. Meanwhile, the interconnected 3D graphene aerogel further serves to reinforce the structure of the Fe3O4/C nanospheres and enhances the electrical conductivity of the overall electrode. Therefore, the carbon matrix and the interconnected graphene network entrap the Fe3O4 nanocrystals such that their electrochemical function is retained even after fracture. This novel hierarchical aerogel structure delivers a long-term stability of 634 mA h g(-1) over 1000 cycles at a high current density of 6 A g(-1) (7 C), and an excellent rate capability of 413 mA h g(-1) at 10 A g(-1) (11 C), thus exhibiting great potential as an anode composite structure for durable high-rate lithium-ion batteries.

  2. RESEARCH INVESTIGATIONS ON THE PROTEOME: 1. MECHANISMS OF REGULATING PROTEIN SYNTHESIS, AND 2. GLOBAL CHARACTERIZATION OF PROTEOMIC RESPONSES TO ARSENIC EXPOSURES

    EPA Science Inventory

    Eukaryotic Elongation Factor 2 (eEF2) mediates translocation in protein synthesis. eEF2 is modified by two post-translational modifications: the phosphorylation of Thr57 in the G domain and a unique conversion of His699 to diphthamide at the tip of domain IV. Diphthamide is the t...

  3. The Dose of Exposure and Prevalence Rates of Post Traumatic Stress Disorder in a Sample of Turkish Children Eleven Months After the 1999 Marmara Earthquakes

    ERIC Educational Resources Information Center

    Bulut, Sefa; Bulut, Solmaz; Tayli, Asli

    2005-01-01

    Since Turkey is a centrally prime earthquake zone, Turkey's children are at risk for developing Post Traumatic Stress Disorder (PTSD) caused by earthquake exposures and threats of anticipated earthquakes. Given the gaps in the literature and the risk to children living in Turkey, the present study was undertaken to investigate the severity and…

  4. Radiation Risk from Chronic Low Dose-Rate Radiation Exposures: The Role of Life-Time Animal Studies - Workshop October 2005

    SciTech Connect

    Gayle Woloschak

    2009-12-16

    As a part of Radiation research conference, a workshop was held on life-long exposure studies conducted in the course of irradiation experiements done at Argonne National Laboratory between 1952-1992. A recent review article documents many of the issues discussed at that workshop.

  5. Stromal concentrations of coenzyme A and its esters are insufficient to account for rates of chloroplast fatty acid synthesis: evidence for substrate channelling within the chloroplast fatty acid synthase.

    PubMed

    Roughan, P G

    1997-10-01

    Concentrations of total CoAs in chloroplasts freshly isolated from spinach and peas were 10-20 microM, assuming a stromal volume of 66 microl per mg of chlorophyll. Acetyl-CoA and CoASH constituted at least 90% of the total CoA in freshly isolated chloroplasts. For a given chloroplast preparation, the concentration of endogenous acetyl-CoA was the same when extractions were performed using HClO4, trichloroacetic acid, propan-2-ol or chloroform/methanol, and the extracts analysed by quantitative HPLC after minimal processing. During fatty acid synthesis from acetate, concentrations of CoASH within spinach and pea chloroplasts varied from less than 0.1 to 5.0 microM. Malonyl-CoA concentrations were also very low (<0.1-3.0 microM) during fatty acid synthesis but could be calculated from radioactivity incorporated from [1-14C]acetate. Concentrations of CoASH in chloroplasts synthesizing fatty acids could be doubled in the presence of Triton X-100, suggesting that the detergent stimulates fatty acid synthesis by increasing the turnover rate of acyl-CoA. However, although taken up, exogenous CoASH (1 microM) did not stimulate fatty acid synthesis by permeabilized spinach chloroplasts. Calculated rates for acetyl-CoA synthetase, acetyl-CoA carboxylase and malonyl-CoA-acyl-carrier protein transacylase reactions at the concentrations of metabolites measured here are < 0.1-4% of the observed rates of fatty acid synthesis from acetate by isolated chloroplasts. The results suggest that CoA and its esters are probably confined within, and channelled through, the initial stages of a fatty acid synthase multienzyme complex.

  6. Size Controlled Two-dimensional Co3O4 with Exposure of {111} Plane: Synthesis and Catalytic Properties for Photooxidation of Organics

    EPA Science Inventory

    The size controlled 2D hexagonal structured Co3O4 with exposure of the {111} plane was fabricated, and the catalytic properties for photooxidation of organics using as-prepared samples were investigated. 2D hexagonal structured Co3O4 with the size of 3 m displays higher photocat...

  7. Irreversible steps in the ferritin synthesis induction pathway.

    PubMed

    Goessling, L S; Mascotti, D P; Bhattacharyya-Pakrasi, M; Gang, H; Thach, R E

    1994-02-11

    The ability of cells to re-repress ferritin synthesis after removal of an inducing agent (iron or heme) was investigated. Re-repression was found to be a slow process, requiring approximately 4 (after iron removal) to 10 h (after heme removal) for completion. Desferrioxamine mesylate (Desferal) had only a slight effect on the rate of re-repression, whereas cycloheximide was strongly inhibitory, indicating that new protein synthesis is required for re-repression. Re-repression occurred at a slow but significant rate in the presence of both Desferal and cycloheximide. These results indicate that, in the absence of an iron chelator, the induction of ferritin synthesis is essentially irreversible. The kinetics of the previously reported covalent modification of IRE-binding protein (IRE-BP) were then examined, to see whether this phenomenon might account (at least in part) for the irreversibility of induction. It was found that the heme- or iron-dependent disappearance of 98-kDa IRE-BP occurred rapidly (within 1 h), and was equally rapidly reversed upon removal of heme after a 1-h exposure. By contrast, after a 4-h exposure to heme, little 98-kDa IRE-BP could be regenerated after heme removal. These results suggest that the slow, irreversible covalent modification of IRE-BP correlates closely over time with the induction of ferritin synthesis. The covalent modification of IRE-BP depends on cell growth rate, and is most readily detected in rapidly growing cells.

  8. Field measurements of incision rates following bedrock exposure: Implications for process controls on the long profiles of valleys cut by rivers and debris flows

    USGS Publications Warehouse

    Stock, Jonathan D.; Montgomery, David R.; Collins, Brian D.; Dietrich, William E.; Sklar, Leonard

    2005-01-01

    Until recently, published rates of incision of bedrock valleys came from indirect dating of incised surfaces. A small but growing literature based on direct measurement reports short-term bedrock lowering at geologically unsustainable rates. We report observations of bedrock lowering from erosion pins monitored over 1–7 yr in 10 valleys that cut indurated volcanic and sedimentary rocks in Washington, Oregon, California, and Taiwan. Most of these channels have historically been stripped of sediment. Their bedrock is exposed to bed-load abrasion, plucking, and seasonal wetting and drying that comminutes hard, intact rock into plates or equant fragments that are removed by higher flows. Consequent incision rates are proportional to the square of rock tensile strength, in agreement with experimental results of others. Measured rates up to centimeters per year far exceed regional long-term erosion-rate estimates, even for apparently minor sediment-transport rates. Cultural artifacts on adjoining strath terraces in Washington and Taiwan indicate at least several decades of lowering at these extreme rates. Lacking sediment cover, lithologies at these sites lower at rates that far exceed long-term rock-uplift rates. This rate disparity makes it unlikely that the long profiles of these rivers are directly adjusted to either bedrock hardness or rock-uplift rate in the manner predicted by the stream power law, despite the observation that their profiles are well fit by power-law plots of drainage area vs. slope. We hypothesize that the threshold of motion of a thin sediment mantle, rather than bedrock hardness or rock-uplift rate, controls channel slope in weak bedrock lithologies with tensile strengths below ∼3–5 MPa. To illustrate this hypothesis and to provide an alternative interpretation for power-law plots of area vs. slope, we combine Shields' threshold transport concept with measured hydraulic relationships and downstream fining rates. In contrast to fluvial

  9. Human tick infestation pattern, tick-bite rate, and associated Borrelia burgdorferi s.l. infection risk during occupational tick exposure at the Seedorf military training area, northwestern Germany.

    PubMed

    Faulde, Michael K; Rutenfranz, Martin; Hepke, Jürgen; Rogge, Mareike; Görner, Andreas; Keth, Alexander

    2014-09-01

    The human tick infestation pattern, tick bite rate, and associated Borrelia burgdorferi s.l.-infection risk were investigated during occupational tick exposure of military personnel at the Seedorf military training area, northwestern Germany, from January to December 2009. Borrelia burgdorferi s.l. seroconversion rates were monitored from April to September 2009. Continuous occupational health surveillance and education were established. Feeding ticks were mostly removed by medical personnel, transferred to 70% ethanol, identified, and tested for B. burgdorferi s.l. Pre- and post-exposure sera were screened for B. burgdorferi s.l. antibodies. A total of 710 feeding ticks was removed, 704 (99.2%) of which were I. ricinus, 5 were I. hexagonus (0.7%), and one was H. concinna (0.1%). Of the I. ricinus specimens, 63.9% were nymphs, 24.7% larvae, 10.9% adult females, and 0.5% adult males. The tick bite rate among occupationally exposed personnel was 42.2% from April to September 2009. Up to 18 simultaneously feeding ticks per person per exposure incident were detected. The mean number of attached ticks was 2.0±2.2 per person per exposure incident. Overall, 86.4% of all feeding ticks were removed from patients within less than 24h after attachment. Borrelia burgdorferi s.l. DNA could be detected in 3.5% of larval, 4.4% of nymphal, 13% of adult female, and 33.3% of adult male ticks, indicating a mean prevalence of 5.3%. Among the genospecies detected, B. afzelii accounted for 84%, B. burgdorferi s.s. for 11%, B. garinii for 3%, and B. spielmanii for 3%. The overall seroconversion rate in 566 personnel exposed from April to September was 1.7%, and 0.7% acquired clinical Lyme borreliosis. Experiences reported herein indicate the need to further improve personal protection measures, health education, and medical staff training in order to minimize exposure to ticks and optimize diagnosis of tick-borne diseases.

  10. Evidence that life history characteristics of wild birds influence infection rates and exposure to influenza A viruses

    USGS Publications Warehouse

    Ely, Craig R.; Hall, Jeffrey S.; Schmutz, Joel A.; Pearce, John M.; Terenzi, John; Sedinger, James S.; Ip, Hon S.

    2013-01-01

    We report on life history characteristics, temporal, and age-related effects influencing the frequency of occurrence of avian influenza (AI) viruses in four species of migratory geese breeding on the Yukon-Kuskokwim Delta, Alaska. Emperor geese (Chen canagica), cackling geese (Branta hutchinsii), greater white-fronted geese (Anser albifrons), and black brant (Branta bernicla), were all tested for active infection of AI viruses upon arrival in early May, during nesting in June, and while molting in July and August, 2006–2010 (n = 14,323). Additionally, prior exposure to AI viruses was assessed via prevalence of antibodies from sera samples collected during late summer in 2009 and 2010. Results suggest that geese are uncommonly infected by low pathogenic AI viruses while in Alaska. The percent of birds actively shedding AI viruses varied annually, and was highest in 2006 and 2010 (1–3%) and lowest in 2007, 2008, and 2009 (95% for emperor geese, a species that spends part of its life cycle in Asia and is endemic to Alaska and the Bering Sea region, compared to 40–60% for the other three species, whose entire life cycles are within the western hemisphere. Birds <45 days of age showed little past exposure to AI viruses, although antibodies were detected in samples from 5-week old birds in 2009. Seroprevalence of known age black brant revealed that no birds <4 years old had seroconverted, compared to 49% of birds ≥4 years of age.

  11. Neurohumoral blood pressure regulation in lead exposure

    SciTech Connect

    Boscolo, P.; Carmignani, M.

    1988-06-01

    Previous human studies demonstrated that lead exposure may modify the metabolism of catecholamines and of hormones controlled by the hypothalamo-pituitary axis and may affect the kallikrein-kinin system. This paper reports unpublished data on the plasma renin activity of lead-exposed workers; these results are in agreement with those of previous human and experimental studies suggesting that the synthesis or release of renin is increased after short and moderate exposure to inorganic lead and reduced whenever the exposure is prolonged. Previous experimental investigations demonstrated that lead may act on the cardiovascular system, with effects on the renin-angiotensin system, on the reactivity to stimulation of peripheral catecholaminergic receptors, on sympathetic and vagal tone, and on reactivity to the stimulation of baroreceptors. This paper reports the results of a study on male Sprague-Dawley rats that received 0, 15, 30, and 60 ..mu..g/mL of lead in drinking water for 18 months. Blood pressure was increased in the rats receiving 30 and 60 ppm of lead; cardiac inotropism was augmented only in those receiving the higher dose of the metal, and heart rate was not modified. Cardiovascular responses to agonists indicated that lead exposure affects the renin-angiotensin system and induces sympathetic hyperactivity be acting on central and peripheral sympathetic junctions increasing the responsiveness to stimulation of ..cap alpha../sub 2/-adrenoreceptors and by increasing the reactivity to stimulation of cardiac and vascular ..beta..-adrenergic and dopaminergic receptors.

  12. Modifying Effect of a Common Polymorphism in the Interleukin-6 Promoter on the Relationship between Long-Term Exposure to Traffic-Related Particulate Matter and Heart Rate Variability

    PubMed Central

    Adam, Martin; Imboden, Medea; Boes, Eva; Schaffner, Emmanuel; Künzli, Nino; Phuleria, Harish Chandra; Kronenberg, Florian; Gaspoz, Jean-Michel; Carballo, David; Probst-Hensch, Nicole

    2014-01-01

    Background Exposure to particulate matter (PM) has been associated with an increase in many inflammatory markers, including interleukin 6 (IL6). Air pollution exposure has also been suggested to induce an imbalance in the autonomic nervous system (ANS), such as a decrease in heart rate variability (HRV). In this study we aimed to investigate the modifying effect of polymorphisms in a major proinflammatory marker gene, interleukin 6 (IL6), on the relationship between long-term exposure to traffic-related PM10 (TPM10) and HRV. Methods For this cross-sectional study we analysed 1552 participants of the SAPALDIA cohort aged 50 years and older. Included were persons with valid genotype data, who underwent ambulatory 24-hr electrocardiogram monitoring, and reported on medical history and lifestyle. Main effects of annual average TPM10 and IL6 gene variants (rs1800795; rs2069827; rs2069840; rs10242595) on HRV indices and their interaction with average annual exposure to TPM10 were tested, applying a multivariable mixed linear model. Results No overall association of TPM10 on HRV was found. Carriers of two proinflammatory G-alleles of the functional IL6 -174 G/C (rs1800795) polymorphism exhibited lower HRV. An inverse association between a 1 µg/m3 increment in yearly averaged TPM10 and HRV was restricted to GG genotypes at this locus with a standard deviation of normal-to-normal intervals (SDNN) (GG-carriers: −1.8%; 95% confidence interval −3.5 to 0.01; pinteraction(additive) = 0.028); and low frequency power (LF) (GG-carriers: −5.7%; 95%CI: −10.4 to −0.8; pinteraction(dominant) = 0.049). Conclusions Our results are consistent with the hypothesis that traffic-related air pollution decreases heart rate variability through inflammatory mechanisms. PMID:25133672

  13. Evaluation and identification of dioxin exposure biomarkers in human urine by high-resolution metabolomics, multivariate analysis and in vitro synthesis.

    PubMed

    Jeanneret, Fabienne; Tonoli, David; Hochstrasser, Denis; Saurat, Jean-Hilaire; Sorg, Olivier; Boccard, Julien; Rudaz, Serge

    2016-01-01

    A previous high-resolution metabolomic study pointed out a dysregulation of urinary steroids and bile acids in human cases of acute dioxin exposure. A subset of 24 compounds was highlighted as putative biomarkers. The aim of the current study was (i) to evaluate the 24 biomarkers in an independent human cohort exposed to dioxins released from the incineration fumes of a municipal waste incinerator and; (ii) to identify them by comparison with authentic chemical standards and biosynthesised products obtained with in vitro metabolic reactions. An orthogonal projection to latent structures discriminant analysis built on biomarker profiles measured in the intoxicated cohort and the controls separated both groups with reported values of 93.8%; 100% and 87.5% for global accuracy; sensitivity and specificity; respectively. These results corroborated the 24 compounds as exposure biomarkers; but a definite identification was necessary for a better understanding of dioxin toxicity. Dehydroepiandrosterone 3β-sulfate, androsterone 3α-glucuronide, androsterone 3α-sulfate, pregnanediol 3α-glucuronide and 11-ketoetiocholanolone 3α-glucuronide were identified by authentic standards. Metabolic reactions characterised four biomarkers: glucuronide conjugates of 11β-hydroxyandrosterone; glycochenodeoxycholic acid and glycocholic acid produced in human liver microsomes and glycoursodeoxycholic acid sulfate generated in cytosol fraction. The combination of metabolomics by high-resolution mass spectrometry with in vitro metabolic syntheses confirmed a perturbed profile of steroids and bile acids in human cases of dioxin exposure. PMID:26474838

  14. Exposure of rats to a high but not low dose of ethanol during early postnatal life increases the rate of loss of optic nerve axons and decreases the rate of myelination

    PubMed Central

    HARRIS, SIMON J.; WILCE, PETER; BEDI, KULDIP S.

    2000-01-01

    Visual system abnormalities are commonly encountered in the fetal alcohol syndrome although the level of exposure at which they become manifest is uncertain. In this study we have examined the effects of either low (ETLD) or high dose (ETHD) ethanol, given between postnatal days 4–9, on the axons of the rat optic nerve. Rats were exposed to ethanol vapour in a special chamber for a period of 3 h per day during the treatment period. The blood alcohol concentration in the ETLD animals averaged ∼ 171 mg/dl and in the ETHD animals ∼ 430 mg/dl at the end of the treatment on any given day. Groups of 10 and 30-d-old mother-reared control (MRC), separation control (SC), ETLD and ETHD rats were anaesthetised with an intraperitoneal injection of ketamine and xylazine, and killed by intracardiac perfusion with phosphate-buffered glutaraldehyde. In the 10-d-old rat optic nerves there was a total of ∼ 145000–165000 axons in MRC, SC and ETLD animals. About 4% of these fibres were myelinated. The differences between these groups were not statistically significant. However, the 10-d-old ETHD animals had only about 75000 optic nerve axons (P < 0.05) of which about 2.8% were myelinated. By 30 d of age there was a total of between 75000–90000 optic nerve axons, irrespective of the group examined. The proportion of axons which were myelinated at this age was still significantly lower (P < 0.001) in the ETHD animals (∼ 77%) than in the other groups (about 98%). It is concluded that the normal stages of development and maturation of the rat optic nerve axons, as assessed in this study, can be severely compromised by exposure to a relatively high (but not low) dose of ethanol between postnatal d 4 and 9. PMID:11117631

  15. Array-CGH analyses of murine malignant lymphomas: genomic clues to understanding the effects of chronic exposure to low-dose-rate gamma rays on lymphomagenesis.

    PubMed

    Takabatake, Takashi; Fujikawa, Katsuyoshi; Tanaka, Satoshi; Hirouchi, Tokuhisa; Nakamura, Masako; Nakamura, Shingo; Braga-Tanaka, Ignacia; Ichinohe, Kazuaki; Saitou, Mikio; Kakinuma, Shizuko; Nishimura, Mayumi; Shimada, Yoshiya; Oghiso, Yoichi; Tanaka, Kimio

    2006-07-01

    We previously reported that mice chronically irradiated with low-dose-rate gamma rays had significantly shorter mean life spans than nonirradiated controls. This life shortening appeared to be due primarily to earlier death due to malignant lymphomas in the irradiated groups (Tanaka et al., Radiat. Res. 160, 376-379, 2003). To elucidate the molecular pathogenesis of murine lymphomas after low-dose-rate irradiation, chromosomal aberrations in 82 malignant lymphomas from mice irradiated at a dose rate of 21 mGy/day and from nonirradiated mice were compared precisely by microarray-based comparative genomic hybridization (array-CGH) analysis. The array carried 667 BAC clones densely selected for the genomic regions not only of lymphoma-related loci but also of surface antigen receptors, enabling immunogenotyping. Frequent detection of the apparent loss of the Igh region on chromosome 12 suggested that most lymphomas in both groups were of B-cell origin. Array-CGH profiles showed a frequent gain of whole chromosome 15 in lymphomas predominantly from the irradiated group. The profiles also demonstrated copy-number imbalances of partial chromosomal regions. Partial gains on chromosomes 12, 14 and X were found in tumors from nonirradiated mice, whereas losses on chromosomes 4 and 14 were significantly associated with the irradiated group. These findings suggest that lymphomagenesis under the effects of continuous low-dose-rate irradiation is accelerated by a mechanism different from spontaneous lymphomagenesis that is characterized by the unique spectrum of chromosomal aberrations. PMID:16808621

  16. Air Change Rates and Interzonal Flows in Residences, and the Need for Multi-Zone Models for Exposure and Health Analysis

    EPA Science Inventory

    Air change rates (ACRs) and interzonal flows are key determinants of indoor air quality (IAQ) and building energy use. This paper characterizes ACRs and interzonal flows in 126 houses, and evaluates effects of these parameters on IAQ. ACRs measured using weeklong tracer measureme...

  17. First Constraints On the Slip Rate of the Yammouneh Fault (Levant Fault System) Determined by Cosmogenic \\textsuperscript{36}Cl Exposure Dating of Offset Alluvial Fans

    NASA Astrophysics Data System (ADS)

    Daëron, M.; Benedetti, L.; Tapponnier, P.; Sursock, A.; Finkel, R.

    2003-12-01

    The most active seismogenic structure along the eastern shore of the Mediterranean is the left-lateral strike-slip Levant fault, plate boundary between Arabia and Africa. To this day there is consensus neither on its present slip rate and segmentation, nor on the exact size and frequence of the earthquakes it generates. Between latitudes 33\\textsuperscript{o} N and 35\\textsuperscript{o} N in Lebanon, the Levant fault's trace veers eastwards by 24\\textsuperscript{o}, forming a 160km-long restraining bend, responsible for the uplift of Mount Lebanon (3083m). Most of the resulting transpressive deformation is partitioned between two main structures: the offshore Tripoli-Beirut thrust and the Yammouneh strike-slip fault, whose degree of seismogenic activity has been questioned (various estimations of its modern slip rate range from 0 to 8mm/yr). Using aerial photographs, satellite images, topographic maps and field observations, we mapped and measured left-laterally offset alluvial fans and gullies along the Yammouneh fault. The measured offsets range from less than 10m to about 3km. To constrain the slip rate of the Yammouneh fault, limestone cobbles were sampled on three alluvial fans, each offset by 40--50m. The concentrations of \\textsuperscript{36}Cl\\ and stable Chlorine in the 48 samples were measured by accelerator mass spectrometry at the LLNL-CAMS. The first results suggest an average slip rate of 5--10mm/yr along the Yammouneh fault in the last 8,000 years.

  18. First Long-Term slip-Rate Along the San Andreas Fault Based on 10Be-26Al Surface Exposure Dating : The Biskra Palms Site, 23 mm/yr for the last 30,000 years.

    NASA Astrophysics Data System (ADS)

    van der Woerd, J.; Klinger, Y.; Sieh, K.; Tapponnier, P.; Ryerson, F.

    2001-12-01

    Slip-rate along the San Andreas fault is known precisely at only two locations : at Wallace Creek, 34 +/- 3 mm/yr for the past 13,500 yrs and at Cajon Creek, 24.5+/- 3 mm/yr for the past 14,500 yrs. When compared to the long-term and far-field plate motion, these rates provide important constraint on how and where strain is accommodated across the plate boundary. Here we present a new determination of the slip-rate along the San Andreas Fault at Biskra Palms, based on 10Be-26Al surface exposure dating. The studied area is located southeast of the San Gorgonio restraining bend, a complex section of the fault which has not produced a large earthquake in historical time. At Biskra Palms, the San Andreas Fault offsets an alluvial fan (T2) about 700 m. Keller et al. (1982) recognized the importance of this site and estimated the age of the offset fan surfaces based on degree of soil development between 20 and 70 kyrs, providing a very loosely constraint slip-rate between 10 and 35 mm/yr. We have analyzed 21 quartz rich cobbles from the surface of the fan, upstream, downstream and within the fault zone. 10Be and 26Al measurements yield consistent results implying simple exposure at the surface. 7 samples collected on the T2 fan surface downstream yield an average exposure age of 30.7 +/- 2.1 kyrs. The tight cluster of these ages indicate no or minor pre-exposition during transport in the small catchment upstream. 7 samples from T2 upstream from the fault yield an average exposure age of 29.5 +/- 2.8 kyrs. One additional sample of this surface (38.4+/-3.6 kyrs) is older than the others and may have been pre-exposed before deposition on the fan. 2 samples from a T2 remnant within the fault zone yield an average age of 29.6 +/- 2.6 kyrs. 4 additional samples were collected from two smaller alluvial surfaces (T3 and T4) remnant found only upstream from the fault zone and yield average ages of 33.3 and 27.3 kyrs that are similar to the age of T2. This suggest that these

  19. Increased rodenticide exposure rate and risk of toxicosis in barn owls (Tyto alba) from southwestern Canada and linkage with demographic but not genetic factors.

    PubMed

    Huang, Andrew C; Elliott, John E; Hindmarch, Sofi; Lee, Sandi L; Maisonneuve, France; Bowes, Victoria; Cheng, Kimberly M; Martin, Kathy

    2016-08-01

    Among many anthropogenic drivers of population decline, continual rapid urbanization and industrialization pose major challenges for the survival of wildlife species. Barn owls (Tyto alba) in southwestern British Columbia (BC) face a multitude of threats ranging from habitat fragmentation to vehicle strikes. They are also at risk from secondary poisoning of second-generation anticoagulant rodenticides (SGARs), a suite of toxic compounds which at high doses results in a depletion of blood clotting factors leading to internal bleeding and death. Here, using long-term data (N = 119) for the hepatic residue levels of SGAR, we assessed the risk of toxicosis from SGAR for the BC barn owl population over the past two decades. We also investigated whether sensitivity to SGAR is associated with genetic factors, namely Single Nucleotide Polymorphisms (SNPs) found in the CYP2C45 gene of barn owls. We found that residue concentration for total SGAR was significantly higher in 2006-2013 (141 ng/g) relative to 1992-2003 (57 ng/g). The proportion of owls exposed to multiple SGAR types was also significantly higher in 2006-2013. Those measures accordingly translate directly into an increase in toxicosis risk level. We also detected demographic differences, where adult females showed on average lower concentration of total SGAR (64 ng/g) when compared to adult males (106 ng/g). Juveniles were overall more likely to show signs of toxicosis than adults (33.3 and 6.9 %, respectively), and those symptoms were positively predicted by SGAR concentrations. We found no evidence that SNPs in the CYP2C45 gene of barn owls were associated with intraspecific variation in SGAR sensitivity. We recommend several preventative measures be taken to minimize wildlife exposure to SGAR. PMID:27151403

  20. Military Exposures

    MedlinePlus

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  1. GLUTATHIONE SYNTHESIS

    PubMed Central

    Lu, Shelly C.

    2012-01-01

    BACKGROUND Glutathione (GSH) is present in all mammalian tissues as the most abundant non-protein thiol that defends against oxidative stress. GSH is also a key determinant of redox signaling, vital in detoxification of xenobiotics, regulates cell proliferation, apoptosis, immune function, and fibrogenesis. Biosynthesis of GSH occurs