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Sample records for rilmenidine attenuates toxicity

  1. Pharmacokinetics of rilmenidine in healthy subjects

    International Nuclear Information System (INIS)

    Genissel, P.; Bromet, N.; Fourtillan, J.B.; Mignot, A.; Albin, H.

    1988-01-01

    Rilmenidine is a novel alpha 2-adrenoceptor agonist, used in the treatment of mild or moderate hypertension at the oral dose of 1 mg once or twice daily. The pharmacokinetic parameters were investigated after single or repeated administration in healthy subjects, using labeled and unlabeled compounds. Rilmenidine was rapidly and extensively absorbed, with an absolute bioavailability factor close to 1 and a maximal plasma concentration achieved within 2 hours. Rilmenidine was not subject to presystemic metabolism. Distribution was independent of the free fraction because rilmenidine was weakly bound to plasma proteins (less than 10%). The volume of distribution was approximately 5 l.kg-1 (315 liters). Elimination was rapid with a total body plasma clearance of approximately 450 ml.min-1 and an elimination half-life of approximately 8 hours. Renal excretion was the major elimination process (two-thirds of the total clearance). Metabolism was very poor, with a renal elimination of rilmenidine as the parent drug (urinary fraction of rilmenidine was about 65% and no metabolite plasma levels were detected). Linear pharmacokinetics were demonstrated for rilmenidine from 0.5 to 2 mg but, at 3 mg, a slight deviation from linearity was observed. In repeated administration, the linear disposition of rilmenidine with dose was confirmed

  2. THE WAYS OF SYMPATHETIC SYSTEM OVERACTIVITY BLOCKING: RILMENIDINE VERSUS ATENOLOL

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    Y. R. Kasherininov

    2006-01-01

    Full Text Available Aim. To evaluate effects of long-term treatment with rilmenidine compared with atenolol on lipid and glucose metabolism and cardiovascular remodeling in hypertension. Material and methods. 37 patients with hypertension were randomized to rilmenidine 1-2 mg/day or atenolol 50-100 mg/day for 26 weeks. Standard oral glucose tolerance test with a parallel measurement of insulin and glucose levels was performed. The “areas under the curve” (AUC for insulin and glucose were calculated. Plasma lipids, left ventricular mass index (LVMI and intima-media thickness (IMT were measured. Brachial artery diameter during reactive hyperemia was used to test endothelium-dependent vasodilatation (EDVD. Results. Blood pressure reduction was equally achieved in both treatment arms. The fasting glucose level increased in the atenolol group from 4.8±0.6 to 5.2±0.7 mmol/l (p<0.01. The AUC of glucose in rilmenidine group decreased from 860±93 to 737±66 mmol/min/l (p<0.05, and it increased from 937±86 to 989±88 mmol/min/l (p<0.05 in the atenolol group. Rilmenidine showed a positive effect on lipid levels, while in the atenolol group a significant decrease of high density lipoprotein was observed. LVMI decreased with rilmenidine by 9.6% (p<0.05 and by 6,9% (not significantly with atenolol. IMT significantly decreased in the rilmenidine. EDVD slightly increased on rilmenidine, while on atenolol group it remained unchanged. Conclusion. Our data suggest that in hypertensive patients central inhibition of sympathetic drive can produce favorable effects on glucose and lipid metabolism compared with standard β-blockade with a similar antihypertensive efficacy. Rilmenidine also provides beneficial effects on cardiovascular remodeling and altered endothelial function in hypertension.

  3. MDMA-induced neurotoxicity of serotonin neurons involves autophagy and rilmenidine is protective against its pathobiology.

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    Mercer, Linda D; Higgins, Gavin C; Lau, Chew L; Lawrence, Andrew J; Beart, Philip M

    2017-05-01

    Toxicity of 3,4-methylenedioxymethamphetamine (MDMA) towards biogenic amine neurons is well documented and in primate brain predominantly affects serotonin (5-HT) neurons. MDMA induces damage of 5-HT axons and nerve fibres and intracytoplasmic inclusions. Whilst its pathobiology involves mitochondrially-mediated oxidative stress, we hypothesised MDMA possessed the capacity to activate autophagy, a proteostatic mechanism for degradation of cellular debris. We established a culture of ventral pons from embryonic murine brain enriched in 5-HT neurons to explore mechanisms of MDMA neurotoxicity and recruitment of autophagy, and evaluated possible neuroprotective actions of the clinically approved agent rilmenidine. MDMA (100 μM-1 mM) reduced cell viability, like rapamycin (RM) and hydrogen peroxide (H 2 O 2 ), in a concentration- and time-dependent manner. Immunocytochemistry revealed dieback of 5-HT arbour: MDMA-induced injury was slower than for RM and H 2 O 2 , neuritic blebbing occurred at 48 and 72 h and Hoechst labelling revealed nuclear fragmentation with 100 μM MDMA. MDMA effected concentration-dependent inhibition of [ 3 H]5-HT uptake with 500 μM MDMA totally blocking transport. Western immunoblotting for microtubule associated protein light chain 3 (LC3) revealed autophagosome formation after treatment with MDMA. Confocal analyses and immunocytochemistry for 5-HT, Hoechst and LC3 confirmed MDMA induced autophagy with abundant LC3-positive puncta within 5-HT neurons. Rilmenidine (1 μM) protected against MDMA-induced injury and image analysis showed full preservation of 5-HT arbours. MDMA had no effect on GABA neurons, indicating specificity of action at 5-HT neurons. MDMA-induced neurotoxicity involves autophagy induction in 5-HT neurons, and rilmenidine via beneficial actions against toxic intracellular events represents a potential treatment for its pathobiology in sustained usage. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Glutathione attenuates uranyl toxicity in Lactococcus lactis

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    Fahmy, Karim; Oertel, Jana [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Biophysics; Obeid, M. [Technische Univ. Dresden (Germany); Solioz, M. [Bern Univ. (Switzerland)

    2017-06-01

    We investigated the role of intracellular glutathione (GSH), which in a large number of taxa plays a role in the protection against the toxicity of heavy metals. Anaerobically grown Lactococcus lactis containing an inducible GSH synthesis pathway was used as a model organism allowing the study of GSH-dependent uranyl detoxification without interference from additional reactive oxygen species. Microcalorimetric measurements of the metabolic heat showed that intracellular GSH attenuates the toxicity of uranium at a concentration in the range of 10-150 μM. Isothermal titration calorimetry revealed the endothermic binding of U(VI) to the carboxyl group(s) of GSH. The data indicate that the primary detoxifying mechanism is the intracellular sequestration of carboxyl-coordinated U(VI) into an insoluble complex with GSH.

  5. Glutathione attenuates uranyl toxicity in Lactococcus lactis

    International Nuclear Information System (INIS)

    Fahmy, Karim; Oertel, Jana; Solioz, M.

    2017-01-01

    We investigated the role of intracellular glutathione (GSH), which in a large number of taxa plays a role in the protection against the toxicity of heavy metals. Anaerobically grown Lactococcus lactis containing an inducible GSH synthesis pathway was used as a model organism allowing the study of GSH-dependent uranyl detoxification without interference from additional reactive oxygen species. Microcalorimetric measurements of the metabolic heat showed that intracellular GSH attenuates the toxicity of uranium at a concentration in the range of 10-150 μM. Isothermal titration calorimetry revealed the endothermic binding of U(VI) to the carboxyl group(s) of GSH. The data indicate that the primary detoxifying mechanism is the intracellular sequestration of carboxyl-coordinated U(VI) into an insoluble complex with GSH.

  6. Actions of rilmenidine on neurogenic hypertension in BPH/2J genetically hypertensive mice.

    Science.gov (United States)

    Jackson, Kristy L; Palma-Rigo, Kesia; Nguyen-Huu, Thu-Phuc; Davern, Pamela J; Head, Geoffrey A

    2014-03-01

    BPH/2J hypertensive mice have an exaggerated sympathetic contribution to blood pressure (BP). Premotor sympathetic neurons within the rostroventrolateral medulla (RVLM) are a major source of sympathetic vasomotor tone and major site of action of the centrally acting sympatholytic agent, rilmenidine. The relative cardiovascular effect of rilmenidine in BPH/2J versus normotensive BPN/3J mice was used as an indicator of the involvement of the RVLM in the sympathetic contribution to hypertension in BPH/2J mice. BPH/2J and BPN/3J mice were pre-implanted with telemetry devices to measure BP in conscious unrestrained mice. Rilmenidine was administered acutely (n=7-9/group), orally for 14 days, at a wide range of doses (n=5/group), and also infused intracerebroventricularly for 7 days (n=6/group). Acute intraperitoneal rilmenidine induced greater depressor and bradycardic responses in BPH/2J than BPN/3J mice (PstrainBPH/2J mice during the dark (active) period (-6.5 ± 2 mmHg; P=0.006). Chronic orally administered rilmenidine (1-12 mg/kg per day) also had minimal effect on 24-h BP in both strains (P>0.16). The sympathetic vasomotor inhibitory effect of rilmenidine is minimal in both strains and similar in hypertensive BPH/2J and BPN/3J mice. Thus, hypertension in BPH/2J mice is not likely mediated by greater neuronal activity in the RVLM, and agents such as rilmenidine would be an ineffective treatment for this form of neurogenic hypertension.

  7. ASSESSMENT OF RILMENIDINE EFFICIENCY IN PATIENTS WITH ARTERIAL HYPERTENSION WITH DETERIORATION OF DAILY PROFILE OF BLOOD PRESSURE

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    P. P. Tikhonov

    2005-01-01

    Full Text Available Aim. To estimate an efficiency and tolerability of rilmenidine in hypertensive patients with different types of blood pressure (BP daily profile – dipper and non-dipper.Methods. 23 patients with essential hypertension (EH, I-II stages, were included into the study. They were treated with rilmeneidine 1 mg daily during one month. Ambulatory BP monitoring (ABPM and office BP measurements were made before and after the treatment. Based on ABPM results all patients were divided into two groups: with adequate decrease of BP at nighttime (dipper, D, and with insufficient decrease of BP at nighttime (non-dipper, ND.Results. One month rilmenidine monotherapy resulted in BP normalization in 52% of patients. Decrease in 24-hour BP, daytime and nighttime BP, burden with BP and BP variability during daytime was observed in both groups. A distinction in rilmenidine influence on BP daily index was revealed: initially normal BP daily index didn’t change in D group, while initially decreased BP daily index increased in ND group. Rilmenidine reduced the speed of morning BP rise in patients of ND group.Conclusion. Results of the study testify efficiency and satisfactory tolerability of monotherapy with rilmenidine 1 mg daily in patients with EH of I-II stages. For patients with insufficient decrease in BP during nighttime rilmenidine provides normalization of BP daily profile intensifying BP night decrease and reducing the speed of morning BP rise.

  8. Toxicity attenuation optimization of crotalic venom by gamma radiation and studies of its immunogenic properties

    International Nuclear Information System (INIS)

    Clissa, Patricia Bianca

    1997-01-01

    Literature data show that 2.0 kGy dose of gamma radiation, generated by 60 source, reduces the toxic activity of Crotalus durissus terrificus venom, without altering its immunogenic capacity. When crotoxin, main toxin from crotalic venom, was irradiated with the same dose, toxicity was also reduced and the immunogenicity was maintained. This fact was attributed to aggregates (compounds with high molecular weight generated during irradiation), that showed no toxicity but were able to induce the antibodies formation against native venom. Crotalus durissus terrificus venom was irradiated with 2.0, 3.0, 5.0 and 10.0 kGy doses and submitted to molecular exclusion chromatography, in order to find an efficient dose that produces large amounts of non toxic but still immunogenic aggregates. After being isolated, the products of irradiation were evaluated for the amount produced, molecular alteration, and toxic and immunogenic activities. These parameters were also analyzed for the whole venom irradiated. The results from different doses irradiated venom were compared with native one, and 2.0 kGy dose was confirmed to be the most efficient in the association of toxicity attenuation with maintenance of immunogenicity of the crotalic venom, while other doses, in spite of being efficient in the toxicity attenuation, they were not able to keep the immunogenicity property. So, the dose of 2.0 kGy could be used to immunize animals in order to improve anticrotalic sera production. (author)

  9. Attenuating the toxicity of cisplatin by using selenosulfate with reduced risk of selenium toxicity as compared with selenite

    International Nuclear Information System (INIS)

    Zhang Jinsong; Peng Dungeng; Lu Hongjuan; Liu Qingliang

    2008-01-01

    It has been reported that high doses of sodium selenite can reduce side effects of cisplatin (CDDP) without compromising its antitumor activity, thus substantially enhancing the cure rate in tumor-bearing mice. However, the toxicity of selenite at high doses should be a concern. The present study revealed that selenosulfate had much lower toxicity, but possessed equal efficacy in selenium (Se) utilization, as compared with selenite at similar doses when used for the intervention of CDDP. In addition, Se accumulation in whole blood and kidney of mice treated with selenosulfate was highly correlated with the survival rate of mice treated with CDDP (both r > 0.96 and both p < 0.05), suggesting that whole blood Se is a potential clinical biomarker to predict host tolerance to CDDP. In either Se-deficient or -sufficient mice bearing solid tumors of hepatoma 22 (H22), selenosulfate did not disturb the therapeutic effect of CDDP on tumors but effectively attenuated the toxicity of CDDP. Furthermore, in a highly malignant cancer model, with Se-sufficient mice bearing ascitic H22 cells, 8 or 10 mg/kg CDDP alone only achieved a null or 25% cure rate, whereas coadministration of selenosulfate with the above two doses of CDDP achieved cure rates of 87.5% or 75%. These results together argue for consideration of selenosulfate as an agent to enhance the therapeutic efficacy of CDDP

  10. The water extract of Veratrilla baillonii could attenuate the subacute toxicity induced by Aconitum brachypodum.

    Science.gov (United States)

    Yu, You; Yi, Xue-Jia; Mei, Zhi-Yi; Li, Jun; Huang, Xian-Ju; Yang, Guang-Zhong; Ma, Li-Qun; Gao, Yue

    2016-12-01

    Aconitum brachypodum Diels (Family Ranunculaceae) is a Chinese ethnodrug and is well known for both its therapeutic application and high toxicity. However, no detoxication strategy is available for the complete elimination of the toxicity of Aconitum plants. Veratrilla baillonii Franch is believed to possess antitoxic effects on the toxicity induced by Aconitum plants and has been clinically used for hundreds of time by Naxi and Lisu nationalities in Yunnan Province of China. To further address the mechanism of the detoxication of Veratrilla baillonii, the effect of water decoction of Veratrilla baillonii (WVBF) on subacute toxicology of SD rats induced by Aconitum brachypodum (CFA), a genus Aconitum, was determined and studied in the present work. The clinical behavior and number of survivors for different dosage of WVBF (25, 50, 100mg/kg) on CFA (4mg/kg) induced rats were observed until day 28. Histological changes and haematological parameters were evaluated. Moreover, Na + -K + -ATPase pathway in heart as well as key enzymes in liver were determined to further discuss the mechanism. The results showed that the exposure of CFA led to some subacute toxicity to rats, especially male ones, accompanied with abnormality of serum biochemical index in rats' serum. The toxicological target organs of CFA may be the heart, liver, kidney and brain. It is demonstrated that WVBF could attenuate the toxicity induced by Aconitum brachypodum via promoting the metabolic enzymes CYP3A1 and CYP3A2 in liver, downregulating the expression of Sodium/Calcium exchanger 1 (NCX1) and SCN5A sodium channal mRNA, and inducing Na + /K + -ATPase activity in heart. This study provides insights into detoxifying measures of Aconitum plants. Aconitum brachypodum may lead to subacute toxicity of rats after long term of administration, and the toxicity could be attenuated by Veratrilla baillonii via promoting the metabolic enzymes in liver, downregulating the expression of NCX1 and SCN5A mRNA, and

  11. The reduced bioavailability of copper by nano-TiO₂ attenuates the toxicity to Microcystis aeruginosa.

    Science.gov (United States)

    Chen, Jinyuan; Qian, Yi; Li, Herong; Cheng, Yanhong; Zhao, Meirong

    2015-08-01

    Nano-TiO2 is a widely applied nanoparticle (NPs) and co-exists with other pollutants such as heavy metals in aquatic environments. However, minimal knowledge is available concerning the ecological risk of these mixtures. Our study reported that at no toxic effect concentrations of TiO2 nanoparticles (5 mg/L), the toxicity of Cu ions to the algae Microcystis aeruginosa was significantly attenuated by TiO2 nanoparticles. Specifically, the concentration of photosynthetic pigments (i.e., concentration of Chla) increased 37% when comparing only Cu ions treated and the nano-TiO2-Cu co-incubation. The levels of phycocyanin (PC), allophycocyanin (APC), phycoerythrin (PE), and phycobiliprotein (PBPs) were also recovered at levels ranging from 23 to 35% after 72 h. For oxidative indexes, the decreased activities of the superoxide dismutase (SOD), peroxidase (POD) content, and malondialdehyde (MDA) with the existence of nano-TiO2 displayed a lower level compared to Cu ions treatment only at 24 and 48 h. This toxicity attenuation can be confirmed by subcellular structures because the impairment to cellular membranes and organelles reduced with the presence of nano-TiO2. The potential mechanisms of the antagonism between the nano-TiO2 and Cu ions can be partially attributed to the sorption of copper onto TiO2 nanoparticles, which fitted the Freundlich isotherm (coefficient = 0.967). The decreased bioavailability of Cu ions protected algae cells from being attacked by free Cu ions. Given the abundance of released nanoparticles and unique physicochemical property of nanoparticles, our results elucidated the ecosafety of nanoparticles and co-substrates in aquatic systems.

  12. Lithium attenuates lead induced toxicity on mouse non-adherent bone marrow cells.

    Science.gov (United States)

    Banijamali, Mahsan; Rabbani-Chadegani, Azra; Shahhoseini, Maryam

    2016-07-01

    Lead is a poisonous heavy metal that occurs in all parts of environment and causes serious health problems in humans. The aim of the present study was to investigate the possible protective effect of lithium against lead nitrate induced toxicity in non-adherent bone marrow stem cells. Trypan blue and MTT assays represented that exposure of the cells to different concentrations of lead nitrate decreased viability in a dose dependent manner, whereas, pretreatment of the cells with lithium protected the cells against lead toxicity. Lead reduced the number and differentiation status of bone marrow-derived precursors when cultured in the presence of colony stimulating factor (CSF), while the effect was attenuated by lithium. The cells treated with lead nitrate exhibited cell shrinkage, DNA fragmentation, anion superoxide production, but lithium prevented lead action. Moreover, apoptotic indexes such as PARP cleavage and release of HMGB1 induced by lead, were protected by lithium, suggesting anti-apoptotic effect of lithium. Immunoblot analysis of histone H3K9 acetylation indicated that lithium overcame lead effect on acetylation. In conclusion, lithium efficiently reduces lead toxicity suggesting new insight into lithium action which may contribute to increased cell survival. It also provides a potentially new therapeutic strategy for lithium and a cost-effective approach to minimize destructive effects of lead on bone marrow stem cells. Copyright © 2016 Elsevier GmbH. All rights reserved.

  13. Mobility and Attenuation Dynamics of Potentially Toxic Chemical Species at an Abandoned Copper Mine Tailings Dump

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    Wilson Mugera Gitari

    2018-02-01

    Full Text Available Large volumes of disposed mine tailings abound in several regions of South Africa, as a consequence of unregulated, unsustainable long years of mining activities. Tailings dumps occupy a large volume of valuable land, and present a potential risk for aquatic systems, through leaching of potentially toxic chemical species. This paper reports on the evaluation of the geochemical processes controlling the mobility of potentially toxic chemical species within the tailings profile, and their potential risk with regard to surface and groundwater systems. Combination of X-ray fluorescence (XRF, X-ray diffraction (XRD, and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS techniques, show that the tailing profiles are uniform, weakly altered, and vary slightly with depth in both physical and geochemical properties, as well as mineralogical composition. Mineralogical analysis showed the following order of abundance: quartz > epidote > chlorite > muscovite > calcite > hematite within the tailings profiles. The neutralization of the dominant alumino-silicate minerals and the absence of sulfidic minerals, have produced medium alkaline pH conditions (7.97–8.37 at all depths and low concentrations of dissolved Cu (20.21–47.9 µg/L, Zn (0.88–1.80 µg/L, Pb (0.27–0.34 µg/L, and SO42− (15.71–55.94 mg/L in the tailings profile leachates. The relative percentage leach for the potentially toxic chemical species was low in the aqueous phase (Ni 0.081%, Cu 0.006%, and Zn 0.05%. This indicates that the transport load of potentially toxic chemical species from tailings to the aqueous phase is very low. The precipitation of secondary hematite has an important known ability to trap and attenuate the mobility of potentially toxic chemical species (Cu, Zn, and Pb by adsorption on the surface area. Geochemical modelling MINTEQA2 showed that the tailings leachates were below saturation regarding oxyhydroxide minerals, but oversaturated with Cu

  14. Flavanone silibinin treatment attenuates nitrogen mustard-induced toxic effects in mouse skin

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    Jain, Anil K.; Tewari-Singh, Neera; Inturi, Swetha; Kumar, Dileep [Department of Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO 80045 (United States); Orlicky, David J. [Department of Pathology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045 (United States); Agarwal, Chapla [Department of Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO 80045 (United States); White, Carl W. [Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045USA (United States); Agarwal, Rajesh, E-mail: Rajesh.Agarwal@UCDenver.edu [Department of Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO 80045 (United States)

    2015-05-15

    Currently, there is no effective antidote to prevent skin injuries by sulfur mustard (SM) and nitrogen mustard (NM), which are vesicating agents with potential relevance to chemical warfare, terrorist attacks, or industrial/laboratory accidents. Our earlier report has demonstrated the therapeutic efficacy of silibinin, a natural flavanone, in reversing monofunctional alkylating SM analog 2-chloroethyl ethyl sulfide-induced toxic effects in mouse skin. To translate this effect to a bifunctional alkylating vesicant, herein, efficacy studies were carried out with NM. Topical application of silibinin (1 or 2 mg) 30 min after NM exposure on the dorsal skin of male SKH-1 hairless mice significantly decreased NM-induced toxic lesions at 24, 72 or 120 h post-exposure. Specifically, silibinin treatment resulted in dose-dependent reduction of NM-induced increase in epidermal thickness, dead and denuded epidermis, parakeratosis and microvesication. Higher silibinin dose also caused a 79% and 51%reversal in NM-induced increases in myeloperoxidase activity and COX-2 levels, respectively. Furthermore, silibinin completely prevented NM-induced H2A.X phosphorylation, indicating reversal of DNA damage which could be an oxidative DNA damage as evidenced by high levels of 8-oxodG in NM-exposed mouse skin that was significantly reversed by silibinin. Together, these findings suggest that attenuation of NM-induced skin injury by silibinin is due to its effects on the pathways associated with DNA damage, inflammation, vesication and oxidative stress. In conclusion, results presented here support the optimization of silibinin as an effective treatment of skin injury by vesicants. - Highlights: • Silibinin treatment attenuated nitrogen mustard (NM)-induced skin injury. • Silibinin affects pathways associated with DNA damage, inflammation and vesication. • The efficacy of silibinin could also be associated with oxidative stress. • These results support testing and optimization of

  15. MK-801, but not drugs acting at strychnine-insensitive glycine receptors, attenuate methamphetamine nigrostriatal toxicity.

    Science.gov (United States)

    Layer, R T; Bland, L R; Skolnick, P

    1993-10-15

    Repeated administration of methamphetamine (METH) results in damage to nigrostriatal dopaminergic neurons. Both competitive N-methyl-D-aspartate (NMDA) receptor antagonists and use-dependent cation channel blockers attenuate METH-induced damage. The objectives of the present study were to examine whether comparable reductions in METH-induced damage could be obtained by compounds acting at strychnine-insensitive glycine receptors on the NMDA receptor complex. Four injections of METH (5 mg/kg i.p.) resulted in a approximately 70.9% depletion of striatal dopamine (DA) and approximately 62.7% depletion of dihydroxyphenylacetic acid (DOPAC) content, respectively. A significant protection against METH-induced DA and DOPAC depletion was afforded by the use-dependent channel blocker, MK-801. The competitive glycine antagonist 7-chlorokynurenic acid (7-Cl-KA), the low efficacy glycine partial agonist (+)-3-amino-1-hydroxy-2-pyrrolidone ((+)-HA-966), and the high efficacy partial glycine agonist 1-aminocyclopropane-carboxylic acid (ACPC) were ineffective against METH-induced toxicity despite their abilities to attenuate glutamate-induced neurotoxicity under both in vivo and in vitro conditions. These results indicate that glycinergic ligands do not possess the same broad neuroprotective spectrum as other classes of NMDA antagonists.

  16. The effects of the alpha2-adrenergic receptor agonists clonidine and rilmenidine, and antagonists yohimbine and efaroxan, on the spinal cholinergic receptor system in the rat

    DEFF Research Database (Denmark)

    Abelson, Klas S P; Höglund, A Urban

    2004-01-01

    Cholinergic agonists produce spinal antinociception via mechanisms involving an increased release of intraspinal acetylcholine. The cholinergic receptor system interacts with several other receptor types, such as alpha2-adrenergic receptors. To fully understand these interactions, the effects...... of various receptor ligands on the cholinergic system must be investigated in detail. This study was initiated to investigate the effects of the alpha2-adrenergic receptor agonists clonidine and rilmenidine and the alpha2-adrenergic receptor antagonists yohimbine and efaroxan on spinal cholinergic receptors......, all ligands possessed affinity for nicotinic receptors. Clonidine and yohimbine binding was best fit to a one site binding curve and rilmenidine and efaroxan to a two site binding curve. The present study demonstrates that the tested alpha2-adrenergic receptor ligands affect intraspinal acetylcholine...

  17. Magnesium capability to attenuate the toxicity of aluminum on the growth of Saccharomyces cerevisiae PE-2

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    Samuel Mariano-da-Silva

    Full Text Available Summary The magnesium (Mg capability to attenuate the toxicity of aluminum (Al for the trehalose content, anaerobic growth, viability and budding rate of Saccharomyces cerevisiae, was studied in this work. Fermentations were carried out in triplicate with sterilized and diluted sugar cane media (4% total reducing sugars/pH 4.0 containing different Al (0.0, 50, 100 and 150 mg L-1 and Mg (0.0, 50 and 100 mg L-1 concentrations. The media were inoculated with 1 mL of 1% (wet basis yeast suspension and incubated at 30ºC, 70 rpm for 20 hours in orbital shaker. At specific times during fermentation portions of cell suspension were taken out and the biomass concentration, yeast viability, budding rate and trehalose content on cells determined. The increase of Al levels, from 0.0 up to 150 mg L-1, showed a reduction on the yeast growth of approximately 95%, 55% and 18% as Mg increased from 0.0 to 50 and 100 mg L-1, respectively. The trehalose content experienced its lowest reduction when greater amounts of Mg were added to the fermentation process. Cell viability showed greater reductions as the content of Al in the media increased. Magnesium effectively protected yeast cells against the deleterious effects of Al on cell growth, viability, budding and trehalose content.

  18. Ginger attenuated di (n-butyl phthalate-induced reproductive toxicity in pubertal male rabbits

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    S. S. Oda

    2017-12-01

    Full Text Available This study was conducted to investigate the toxic effects of di (n-butyl phthalate (DBP on reproductive functions in male rabbits and the probable protective role of ginger. Twenty rabbits were divided equally into 4 groups: control group; DBP group (520 mg/kg body weight [BW] DBP orally, DBP+ginger group (520 mg/kg BW DBP and 400 mg/kg BW ginger and ginger group (400 mg/kg BW ginger orally. Treatments were given three-times/week. After 7 wk of the experiment, DBP induced significant reduction in testis and prostate weights, serum and intratesticular testosterone concentrations, sperm counts both mass and progressive sperm motility and live sperms percentage as well as significant elevation of testicular malondialdehyde compared to control group. No significant changes were detected in epididymal weights, serum FSH and serum LH concentrations and testicular total superoxide dismutase and glutathione peroxidase activities in all treated groups. DBP induced considerable histopathological alterations in testis and to minimal extent in epididymis and prostates. Ginger treatment attenuated the significant changes to a certain extent induced by DBP intoxication in male rabbits probably due to its potential to scavenge free radicals.

  19. Chemopreventive agents attenuate rapid inhibition of gap junctional intercellular communication induced by environmental toxicants

    Czech Academy of Sciences Publication Activity Database

    Babica, Pavel; Čtveráčková, Lucie; Lenčešová, Zuzana; Trosko, J. E.; Upham, B. L.

    2016-01-01

    Roč. 68, č. 5 (2016), s. 827-837 ISSN 0163-5581 R&D Projects: GA MŠk LH12034 Institutional support: RVO:67985939 Keywords : gap junctional intercellular communication * chemopreventive agents * environmental toxicants Subject RIV: FR - Pharmacology ; Medidal Chemistry Impact factor: 2.447, year: 2016

  20. Evaluation of the attenuating properties of selected Greek clays for toxic inorganic elements in landfill sites.

    Science.gov (United States)

    Mimides, T; Perraki, T

    2000-05-15

    Heavy metal attenuation properties of selected clay material collected from miscellaneous Greek sites is investigated and tested in the laboratory for their suitability, either as liners in hydrologically unsafe sites or as earth covers for sanitary landfill sites. Eleven potentially hazardous elements (As, Be, Cd, Cr, Cu, Hg, Ni, Pb, Se, V, and Zn) generated by a co-disposal landfill leachate have been considered. Experimental column and static equilibrium methods for the determination of dispersion and adsorption are described. Molecular diffusion dominates the migration phenomena with a velocity range between 1.3 x 10(-5) and 3.5 x 10(-4) cm/s throughout the experiments. A simple way to evaluate dispersion coefficients from breakthrough curves gave values of between 3.90 x 10(-6) and 3.5 x 10(-4) cm2/s, with a mean value of 1.5 x 10(-5). Static adsorption equilibrium studies supported by column runs showed that Freundlich (F = kCn) isotherms express in a better way the assimilative capacities of the tested clays, with k and n values ranging from 0.06 to 1.99 and 0.55 to 1.48 correspondingly. Mathematical models involving non-linear parabolic equations are involved. The experimental data, together with finite difference techniques and some physical clay characteristics, produced trilinear textural diagrams and predictive flow transport convection-dispersion breakthrough curves for a quick estimation of the attenuating properties of clays for heavy metals.

  1. Attenuated effects of chitosan-capped gold nanoparticles on LPS-induced toxicity in laboratory rats

    International Nuclear Information System (INIS)

    Stefan, Marius; Melnig, Viorel; Pricop, Daniela; Neagu, Anca; Mihasan, Marius; Tartau, Liliana; Hritcu, Lucian

    2013-01-01

    The impact of nanoparticles in medicine and biology has increased rapidly in recent years. Gold nanoparticles (AuNP) have advantageous properties such as chemical stability, high electron density and affinity to biomolecules. However, the effects of AuNP on human body after repeated administration are still unclear. Therefore, the purpose of the present study was to evaluate the effects of gold-11.68 nm (AuNP1, 9.8 μg) and gold-22.22 nm (AuNP2, 19.7 μg) nanoparticles capped with chitosan on brain and liver tissue reactivity in male Wistar rats exposed to lipopolysaccharide (LPS from Escherichia coli serotype 0111:B4, 250 μg) upon 8 daily sessions of intraperitoneal administration. Our results suggest that the smaller size of chitosan-capped AuNP shows the protective effects against LPS-induced toxicity, suggesting a very high potential for biomedical applications. - Highlights: ► Smaller size of chitosan-capped gold nanoparticles acts against LPS-induced toxicity. ► Larger size of chitosan-capped gold nanoparticles agglomerated inside neurons and induced toxicity in combination with LPS. ► Chitosan has excellent biocompatible proprieties. ► Smaller size of chitosan-capped gold nanoparticles demonstrates great potential in biomedical applications.

  2. NAD+ Supplementation Attenuates Methylmercury Dopaminergic and Mitochondrial Toxicity in Caenorhabditis Elegans

    Science.gov (United States)

    Caito, Samuel W.; Aschner, Michael

    2016-01-01

    Methylmercury (MeHg) is a neurotoxic contaminant of our fish supply that has been linked to dopaminergic (DAergic) dysfunction that characterizes Parkinson’s disease. We have previously shown that MeHg causes both morphological and behavioral changes in the Caenorhabditis elegans DAergic neurons that are associated with oxidative stress. We were therefore interested in whether the redox sensitive cofactor nicotinamide adenine dinucleotide (NAD+) may be affected by MeHg and whether supplementation of NAD + may prevent MeHg-induced toxicities. Worms treated with MeHg showed depletion in cellular NAD + levels, which was prevented by NAD + supplementation prior to MeHg treatment. NAD + supplementation also prevented DAergic neurodegeneration and deficits in DAergic-dependent behavior upon MeHg exposure. In a mutant worm line that cannot synthesize NAD + from nicotinamide, MeHg lethality and DAergic behavioral deficits were more sensitive to MeHg than wildtype worms, demonstrating the importance of NAD + in MeHg toxicity. In wildtype worms, NAD + supplementation provided protection from MeHg-induced oxidative stress and mitochondrial dysfunction. These data show the importance of NAD + levels in the response to MeHg exposure. NAD + supplementation may be beneficial for MeHg-induced toxicities and preventing cellular damage involved in Parkinson’s disease. PMID:26865665

  3. Curcumin Attenuates Amyloid-β Aggregate Toxicity and Modulates Amyloid-β Aggregation Pathway.

    Science.gov (United States)

    Thapa, Arjun; Jett, Stephen D; Chi, Eva Y

    2016-01-20

    The abnormal misfolding and aggregation of amyloid-β (Aβ) peptides into β-sheet enriched insoluble deposits initiates a cascade of events leading to pathological processes and culminating in cognitive decline in Alzheimer's disease (AD). In particular, soluble oligomeric/prefibrillar Aβ have been shown to be potent neurotoxins. The naturally occurring polyphenol curcumin has been shown to exert a neuroprotective effect against age-related neurodegenerative diseases such as AD. However, its protective mechanism remains unclear. In this study, we investigated the effects of curcumin on the aggregation of Aβ40 as well as Aβ40 aggregate induced neurotoxicity. Our results show that the curcumin does not inhibit Aβ fibril formation, but rather enriches the population of "off-pathway" soluble oligomers and prefibrillar aggregates that were nontoxic. Curcumin also exerted a nonspecific neuroprotective effect, reducing toxicities induced by a range of Aβ conformers, including monomeric, oligomeric, prefibrillar, and fibrillar Aβ. The neuroprotective effect is possibly membrane-mediated, as curcumin reduced the extent of cell membrane permeabilization induced by Aβ aggregates. Taken together, our study shows that curcumin exerts its neuroprotective effect against Aβ induced toxicity through at least two concerted pathways, modifying the Aβ aggregation pathway toward the formation of nontoxic aggregates and ameliorating Aβ-induced toxicity possibly through a nonspecific pathway.

  4. Immobilized nickel hexacyanoferrate on activated carbons for efficient attenuation of radio toxic Cs(I) from aqueous solutions

    International Nuclear Information System (INIS)

    Lalhmunsiama; Lalhriatpuia, C.; Tiwari, Diwakar; Lee, Seung-Mok

    2014-01-01

    Highlights: • Rice hulls and areca nut wastes are utilized to obtain activated carbons. • Nickel hexacyanoferrate is immobilized on activated carbon samples. • Materials are characterized by SEM–EDX and XRD data. • Materials are employed in attenuation of Cs(I) under batch and column studies. • Possible mechanism is deduced at solid/solution interface. - Abstract: The aim of this study is to immobilize nickel hexacyanoferrate onto the large surface of activated carbons (ACs) precursor to rice hulls and areca nut waste materials. These nickel hexacyanoferrate immobilized materials are then assessed in the effective attenuation of radio logically important cesium ions from aqueous solutions. The solid samples are characterized by the XRD analytical method and surface morphology is obtained from the SEM images. The batch reactor experiments show that an increase in sorptive pH (2.0–10.0) apparently not affecting the high percent uptake of Cs(I). Equilibrium modeling studies suggest that the data are reasonably and relatively fitted well to the Langmuir adsorption isotherm. Kinetic studies show that sorption process is fairly rapid and the kinetic data are fitted well to the pseudo-second order rate model. Increasing the background electrolyte concentration from 0.001 to 0.1 mol/L NaCl causes insignificant decrease in Cs(I) removal which infers the higher selectivity of these materials for Cs(I) from aqueous solutions. Further, the column reactor operations enable to obtain the breakthrough data which are then fitted to the Thomas non-linear equation as to obtain the loading capacity of column for Cs(I). The results show that the modified materials show potential applicability in the attenuation of radio toxic cesium from aqueous solution

  5. Attenuation of rotenone toxicity in SY5Y cells by taurine and N-acetyl cysteine alone or in combination.

    Science.gov (United States)

    Alkholifi, Faisal K; Albers, David S

    2015-10-05

    There is accumulating evidence that supports the involvement of reactive oxygen species (ROS), mitochondrial dysfunction and inflammation in the pathogenesis of neurodegenerative diseases. Thus, it is plausible that a multi-targeted therapeutic approach may be a more effective strategy to retard or even potentially halt the progression of the disease. Taurine is an organic acid that has a role in the regulation of oxidative stress and promoting mitochondrial normal functions, and N-Acetyl cysteine (NAC) is a well-known anti-oxidant and glutathione precursor. The main purpose of this study was to examine the cytoprotective effects of taurine alone or in combination with NAC against rotenone-induced toxicity in the SH-SY5Y neuroblastoma cell line. Taurine treatment produced a concentration-dependent reduction in rotenone-induced cell death. From this, we tested sub-effective concentrations of taurine in combination with low, sub-effective concentrations of NAC against rotenone toxicity, and found the combined treatment afforded greater cytoprotection than either treatment alone. The combined taurine/NAC treatment also attenuated rotenone-induced reductions in aconitase activity suggesting the cytoprotection afforded by the combined treatment may be associated with anti-oxidative mechanisms. Together, our data suggest that a multi-targeted approach may yield new avenues of research exploring the utility of combining therapeutic agents with different mechanisms of actions at concentrations lower than previously tested and shown to be cytoprotective. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Lipid Emulsion Inhibits Vasodilation Induced by a Toxic Dose of Bupivacaine via Attenuated Dephosphorylation of Myosin Phosphatase Target Subunit 1 in Isolated Rat Aorta

    Science.gov (United States)

    Ok, Seong-Ho; Byon, Hyo-Jin; Kwon, Seong-Chun; Park, Jungchul; Lee, Youngju; Hwang, Yeran; Baik, Jiseok; Choi, Mun-Jeoung; Sohn, Ju-Tae

    2015-01-01

    Lipid emulsions are widely used for the treatment of systemic toxicity that arises from local anesthetics. The goal of this in vitro study was to examine the cellular mechanism associated with the lipid emulsion-mediated attenuation of vasodilation induced by a toxic dose of bupivacaine in isolated endothelium-denuded rat aorta. The effects of lipid emulsion on vasodilation induced by bupivacaine, mepivacaine, and verapamil were assessed in isolated aorta precontracted with phenylephrine, the Rho kinase stimulant NaF, and the protein kinase C activator phorbol 12,13-dibutyrate (PDBu). The effects of Rho kinase inhibitor Y-27632 on contraction induced by phenylephrine or NaF were assessed. The effects of bupivacaine on intracellular calcium concentrations ([Ca2+]i) and tension induced by NaF were simultaneously measured. The effects of bupivacaine alone and lipid emulsion plus bupivacaine on myosin phosphatase target subunit 1 (MYPT1) phosphorylation induced by NaF were examined in rat aortic vascular smooth muscle cells. In precontracted aorta, the lipid emulsion attenuated bupivacaine-induced vasodilation but had no effect on mepivacaine-induced vasodilation. Y-27632 attenuated contraction induced by either phenylephrine or NaF. The lipid emulsion attenuated verapamil-induced vasodilation. Compared with phenylephrine-induced precontracted aorta, bupivacaine-induced vasodilation was slightly attenuated in NaF-induced precontracted aorta. The magnitude of the bupivacaine-induced vasodilation was higher than that of a bupivacaine-induced decrease in [Ca2+]i. Bupivacaine attenuated NaF-induced MYPT1 phosphorylation, whereas lipid emulsion pretreatment attenuated the bupivacaine-induced inhibition of MYPT1 phosphorylation induced by NaF. Taken together, these results suggest that lipid emulsions attenuate bupivacaine-induced vasodilation via the attenuation of inhibition of MYPT1 phosphorylation evoked by NaF. PMID:26664257

  7. Curcumin mediated attenuation of carbofuran induced toxicity in the heart of Wistar rats.

    Science.gov (United States)

    Jaiswal, S K; Gupta, V K; Siddiqi, N J; Sharma, B

    2017-07-31

    Carbofuran is used to improve the agricultural productivity as well as to protect the house hold and industrial products, but due to accumulation in the biological system, it causes serious side effects in many non-targets mammalian systems. The aim of present study is to evaluate the carbofuran induced oxidative stress in rat heart and its attenuation by using herbal product curcumin. Rats were divided into four groups; one group received 20 % LD50 of carbofuran another group of rats received same doses of carbofuran was  pretreated with curcumin (100 mg kg-1 body weight) and remaining two other groups served as control and curcumin treated animals. The activity of lactate dehydrogenase (LDH) in the heart tissues and serum was evaluated and the activity of enzymatic antioxidants superoxide dismutase (SOD) and catalase (CAT) was estimated in the heart tissues. The level of malondialdehyde (MDA) in heart tissues was also measured. The Total cholesterol (TC) and high density lipoprotein (HDL) was measured in the serum of the entire animals group. The results of present study showed that the activity of LDH in heart tissues were decreased and in serum was elevated. The MDA level was significantly elevated due to exposure of carbofuran. The enzymatic antioxidants, SOD and CAT activities were also inhibited. The ratio of pro-oxidant (P)/antioxidant (A) was also found to be sharply increased in the rat heart tissues of carbofuran exposed animals. The alterations in all the parameter were recovered by the pretreatment of curcumin (100 mg kg-1 body weight).

  8. Hsp90 chaperone inhibitor 17-AAG attenuates Aβ-induced synaptic toxicity and memory impairment.

    Science.gov (United States)

    Chen, Yaomin; Wang, Bin; Liu, Dan; Li, Jing Jing; Xue, Yueqiang; Sakata, Kazuko; Zhu, Ling-qiang; Heldt, Scott A; Xu, Huaxi; Liao, Francesca-Fang

    2014-02-12

    The excessive accumulation of soluble amyloid peptides (Aβ) plays a crucial role in the pathogenesis of Alzheimer's disease (AD), particularly in synaptic dysfunction. The role of the two major chaperone proteins, Hsp70 and Hsp90, in clearing misfolded protein aggregates has been established. Despite their abundant presence in synapses, the role of these chaperones in synapses remains elusive. Here, we report that Hsp90 inhibition by 17-AAG elicited not only a heat shock-like response but also upregulated presynaptic and postsynaptic proteins, such as synapsin I, synaptophysin, and PSD95 in neurons. 17-AAG treatment enhanced high-frequency stimulation-evoked LTP and protected neurons from synaptic damage induced by soluble Aβ. In AD transgenic mice, the daily administration of 17-AAG over 7 d resulted in a marked increase in PSD95 expression in hippocampi. 17-AAG treatments in wild-type C57BL/6 mice challenged by soluble Aβ significantly improved contextual fear memory. Further, we demonstrate that 17-AAG activated synaptic protein expression via transcriptional mechanisms through the heat shock transcription factor HSF1. Together, our findings identify a novel function of Hsp90 inhibition in regulating synaptic plasticity, in addition to the known neuroprotective effects of the chaperones against Aβ and tau toxicity, thus further supporting the potential of Hsp90 inhibitors in treating neurodegenerative diseases.

  9. Natural attenuation of toxic metal phytoavailability in 35-year-old sewage sludge-amended soil.

    Science.gov (United States)

    Tai, Yiping; Li, Zhian; Mcbride, Murray B

    2016-04-01

    Toxic heavy metals persist in agricultural soils and ecosystem for many decades after their application as contaminants in sewage sludge and fertilizer products This study assessed the potential long-term risk of cadmium (Cd), lead (Pb), zinc (Zn), and copper (Cu) in land-applied sewage sludge to food crop contamination. A sewage sludge-amended soil (SAS) aged in the field more than 35 years was used in a greenhouse pot experiment with leafy vegetables (lettuce and amaranth) having strong Cd and Zn accumulation tendencies. Soil media with variable levels of available Cd, Zn, and Cu (measured using 0.01 M CaCl2 extraction) were prepared by diluting SAS with several levels of uncontaminated control soil. Despite long-term aging in the field, the sludge site soil still retains large reserves of heavy metals, residual organic matter, phosphorus, and other nutrients, but its characteristics appear to have stabilized over time. Nevertheless, lettuce and amaranth harvested from the sludge-treated soil had undesirable contents of Cd and Zn. The high plant uptake efficiency for Cd and Zn raises a concern regarding the quality and safety of leafy vegetables in particular, when these crops are grown on soils that have been amended heavily with sewage sludge products at any time in their past.

  10. Flame retardant tris(1,3-dichloro-2-propylphosphate (TDCPP toxicity is attenuated by N-acetylcysteine in human kidney cells

    Directory of Open Access Journals (Sweden)

    David W. Killilea

    Full Text Available Prolonged exposure to the flame retardants found in many household products and building materials is associated with adverse developmental, reproductive, and carcinogenic consequences. While these compounds have been studied in numerous epidemiological and animal models, less is known about the effects of flame retardant exposure on cell function. This study evaluated the toxicity of the commonly used fire retardant tris(1,3-dichloro-2-propylphosphate (TDCPP in cell line derived from the kidney, a major tissue target of organohalogen toxicity. TDCPP inhibited cell growth at lower concentrations (IC50 27 μM, while cell viability and toxicity were affected at higher concentrations (IC50 171 μM and 168 μM, respectively. TDCPP inhibited protein synthesis and caused cell cycle arrest, but only at higher concentrations. Additionally, the antioxidant N-acetylcysteine (NAC reduced cell toxicity in cells treated with TDCPP, suggesting that exposure to TDCPP increased oxidative stress in the cells. In summary, these data show that low concentrations of TDCPP result in cytostasis in a kidney cell line, whereas higher concentrations induce cell toxicity. Furthermore, TDCPP toxicity can be attenuated by NAC, suggesting that antioxidants may be effective countermeasures to some organohalogen exposures. Keywords: flame retardant, cytostasis, cell toxicity, antioxidant, cell cycle

  11. A novel natural Nrf2 activator with PPARγ-agonist (monascin) attenuates the toxicity of methylglyoxal and hyperglycemia

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, Wei-Hsuan; Lee, Bao-Hong; Chang, Yu-Ying [Department of Biochemical Science and Technology, College of Life Science, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan (China); Hsu, Ya-Wen [SunWay Biotechnology Company, Taipei, Taiwan (China); Pan, Tzu-Ming, E-mail: tmpan@ntu.edu.tw [Department of Biochemical Science and Technology, College of Life Science, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan (China)

    2013-11-01

    Methylglyoxal (MG) is a toxic-glucose metabolite and a major precursor of advanced glycation endproducts (AGEs). MG has been reported to result in inflammation by activating receptor for AGEs (RAGE). We recently found that Monascus-fermented metabolite monascin acts as a novel natural peroxisome proliferator-activated receptor-γ (PPARγ) agonist that improves insulin sensitivity. We investigated the metabolic, biochemical, and molecular abnormalities characteristic of type 2 diabetes in MG-treated Wistar rats treated with oral administration of monascin or rosiglitazone. Monascin (a novel PPARγ agonist) activated nuclear factor-erythroid 2-related factor 2 (Nrf2) and down-regulated hyperinsulinmia in oral glucose tolerance test (OGTT). Monascin was able to elevate glyoxalase-1 expression via activation of hepatic Nrf2, hence, resulting in MG metabolism to D-lactic acid and protected from AGEs production in MG-treated rats. Rosiglitazone did not activate Nrf2 nor glyoxalase expression to lower serum and hepatic AGEs levels. Monascin acts as a novel natural Nrf2 activator with PPARγ-agonist activity were confirmed by Nrf2 and PPARγ reporter assays in Hep G2 cells. These findings suggest that monascin acts as an anti-diabetic and anti-oxidative stress agent to a greater degree than rosiglitazone and thus may have therapeutic potential for the prevention of diabetes. - Highlights: • Monascin acts as a PPARgamma agonist. • Monascin activates Nrf2 and AMPK. • Monascin promotes MG metabolism into D-lactic acid. • Monascin attenuates inflammation and diabetes in vivo.

  12. A novel technology for neutralizing acidity and attenuating toxic chemical species from acid mine drainage using cryptocrystalline magnesite tailings

    CSIR Research Space (South Africa)

    Masindi, Vhahangwele

    2016-04-01

    Full Text Available neutralize and attenuate elevated concentrations of chemical species in AMD to within prescribed legal frameworks for water use in agricultural and industrial sectors in South Africa....

  13. Beta-lyase-dependent attenuation of cisplatin-mediated toxicity by selenocysteine Se-conjugates in renal tubular cell lines

    NARCIS (Netherlands)

    Rooseboom, Martijn; Schaaf, Gerben; Commandeur, Jan N M; Vermeulen, Nico P E; Fink-Gremmels, Johanna

    Cisplatin [cis-diamminedichloroplatinum(II)] is a widely used antitumor drug with dose-limiting nephrotoxic side effects due to selective toxicity to the proximal tubule. In the present study, the chemoprotective potential of three selenocysteine Se-conjugates, Se-methyl-L-selenocysteine,

  14. NMR-based metabonomics study on the effect of Gancao in the attenuation of toxicity in rats induced by Fuzi.

    Science.gov (United States)

    Sun, Bo; Wang, Xubin; Cao, Ruili; Zhang, Qi; Liu, Qiao; Xu, Meifeng; Zhang, Ming; Du, Xiangbo; Dong, Fangting; Yan, Xianzhong

    2016-12-04

    Fuzi, the processed lateral root of Aconitum carmichaelii Debeaux, is a traditional Chinese medicine used for its analgesic, antipyretic, anti-rheumatoid arthritis and anti-inflammation effects; however, it is also well known for its toxicity. Gancao, the root of Glycyrrhiza uralensis Fisch., is often used concurrently with Fuzi to alleviate its toxicity. However, the mechanism of detoxication is still not well clear. In this study, the effect of Gancao on the metabolic changes induced by Fuzi was investigated by NMR-based metabonomic approaches. Fifty male Wistar rats were randomly divided into five groups (group A: control, group B: Fuzi decoction alone, group C: Gancao decoction alone, group D: Fuzi decoction and Gancao decoction simultaneously, group E: Fuzi decoction 5h after Gancao decoction) and urine samples were collected for NMR-based metabolic profiling analysis. Statistical analyses such as unsupervised PCA, t-test, hierarchical cluster, and pathway analysis were used to detect the effects of Gancao on the metabolic changes induced by Fuzi. The behavioral and biochemical characteristics showed that Fuzi exhibited toxic effects on treated rats (group B) and statistical analyses showed that their metabolic profiles were in contrast to those in groups A and C. However, when Fuzi was administered with Gancao, the metabolic profiles became similar to controls, whereby Gancao reduced the levels of trimethylamine N-oxide, betaine, dimethylglycine, valine, acetoacetate, citrate, fumarate, 2-ketoglutarate and hippurate, and regulated the concentrations of taurine and 3-hydroxybutyrate, resulting in a decrease in toxicity. Furthermore, important pathways that are known to be involved in the effect of Gancao on Fuzi, including phenylalanine, tyrosine and tryptophan biosynthesis, the synthesis and degradation of ketone bodies, and the TCA cycle, were altered in co-treated rats. Gancao treatment mitigated the metabolic changes altered by Fuzi administration in rats

  15. Lycopene attenuates Aβ1-42 secretion and its toxicity in human cell and Caenorhabditis elegans models of Alzheimer disease.

    Science.gov (United States)

    Chen, Wei; Mao, Liuqun; Xing, Huanhuan; Xu, Lei; Fu, Xiang; Huang, Liyingzi; Huang, Dongling; Pu, Zhijun; Li, Qinghua

    2015-11-03

    Growing evidence suggests concentration of lycopene was reduced in plasma of patients with Alzheimer disease (AD). Lycopene, a member of the carotenoid family, has been identified as an antioxidant to attenuate oxidative damage and has neuroprotective role in several AD models. However, whether lycopene is involved in the pathogenesis of AD and molecular underpinnings are elusive. In this study, we found that lycopene can significantly delay paralysis in the Aβ1-42-transgenic Caenorhabditis elegans strain GMC101. Lycopene treatment reduced Aβ1-42 secretion in SH-SY5Y cells overexpressing the Swedish mutant form of human β-amyloid precursor protein (APPsw). Next, we found lycopene can down-regulate expression level of β-amyloid precursor protein(APP) in APPsw cells. Moreover, lycopene treatment can not change endogenous reactive oxygen species level and apoptosis in APPsw cells. However, lycopene treatment protected against H2O2-induced oxidative stress and copper-induced damage in APPsw cells. Collectively, our data support that elevated lycopene contributes to the lower pathogenesis of AD. Our findings suggest that increasing lycopene in neurons may be a novel approach to attenuate onset and development of AD. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  16. The Effects of Piroxicam in the Attenuation of MPP+/MPTP Toxicity In Vitro and In Vivo

    Science.gov (United States)

    Soliman, Y.; Jackson, T.; Mazzio, E.

    2010-01-01

    Several lines of evidence support the neuroprotective action of cyclooxygenase-2 (COX-2) inhibitors in various models of Parkinson's disease (PD). In the current study, we investigated the neuroprotective properties of several COX inhibitors against 1-methyl-4-phenylpyridinium (MPP+) in neuroblastoma Neuro 2A (N-2A) cells in vitro and the protection against degeneration of substantia nigra pars compacta (SNc) dopaminergic (DA) neurons after the administration of 1-methyl 4-phenyl 1,2,3,6-tetrahydropyridine (MPTP) in C57/BL6 male mice. The data obtained demonstrate a lack of protective effects observed by COX 1-2 inhibitors ibuprofen and acetylsalicylic acid against MPP+ toxicity in N-2A, where piroxicam was protective in a dose dependent manner (MPP+ control: 15 ± 2% MPP+ piroxicam: 5 mM 89 ± 4%). The data also indicate a drop in mitochondrial oxygen (O2) consumption and ATP during MPP+ toxicity with no restoration of mitochondrial function concurrent to a heightened concentration of somatic ATP during piroxicam rescue. These findings indicate that the neuroprotective effects of COX inhibitors against MPP+ are not consistent, but that piroxicam may work through an unique mechanism to propel anaerobic energy metabolism. On the other hand, using mice, piroxicam (20 mg/kg) was effective against MPTP-induced dopaminergic degeneration in the (SNc) and loss of locomotive function in mice. Administering a 3 day pre-treatment of piroxicam (20 mg/kg) was effective in antagonizing the losses in SNc tyrosine hydroxylase protein expression, SNc DA concentration and associated anomaly in ambulatory locomotor activity. It was concluded from these findings that piroxicam is unique among COX inhibitors in providing very significant neuroprotection against MPP+ in vitro and in vivo. PMID:18612814

  17. In vivo pretreatment of Eudrilus eugeniae powder attenuates β-adrenoceptor toxicity mediated by isoproterenol in rat model

    Directory of Open Access Journals (Sweden)

    Jaganathan Anitha

    2016-08-01

    Full Text Available The present study was designed to discover the potential cardioprotective function of earthworm powder (EWP extracted from Eudrilus eugeniae on isoproterenol (ISO-induced myocardial infarction in male Wistar rats. The rats were divided into four groups, with six rats in each group. Certain rats were pretreated with EWP (200 mg/kg bwt (Group III, and a myocardial infarction was then induced by subcutaneous injection of ISO (85 mg/kg bwt (Group II. Oral pretreatment of 200 mg/kg bwt of EWP for 28 days significantly (p > 0.05 improved the blood profile levels, including (a the lipid profile of total cholesterol (TC, free fatty acids (FFA, and triglycerides (TG; (b low-density lipoprotein (LDL, very low-density lipoprotein (VLDL, high-density lipoprotein (HDL, and protein; and (c A/G ratio, glucose and uric acid levels. The electrophoretic pattern of elevated lactose dehydrogenase (LDH levels was recovered by EWP treatment as evidenced by comparison with ISO-induced rats with cardiac damage. The above results indicate that EWP (200 mg/kg bwt provides a cardioprotective effect by attenuating the blood profile, lipid profile, biochemical levels, and LDH patterns in rats that experienced an ISO-induced myocardial infarction.

  18. The Effect of Rebadioside A on Attenuation of Oxidative Stress in Kidney of Mice under Acetaminophen Toxicity

    Directory of Open Access Journals (Sweden)

    Seyed Ali Hashemi

    2014-11-01

    Full Text Available Background: Acetaminophen (APAP overdose causes renal and hepatic injury. It is also believed that oxidative stress has a pivotal role in APAP-induced renal injury. Therefore, protective effects of different antioxidants have been examined in APAP-induced renal and hepatic toxicity models. Stevia rebadiana is a plant with a high degree of natural antioxidant activity in its leaf extract. The aim of this study was to investigate the possible protective effects of rebadioside A; one of the main components of stevia extract, on APAP-induced oxidative stress in kidney of mice. Methods: Oxidative stress was induced in kidney of BALB/c mice by the intraperitoneal (i.p. administration of a single dose of 300 mg/kg APAP. Some of these mice also received rebadioside A (700 mg/kg (i.p. 30 minutes after APAP injection. Two and six hours after APAP injection, all mice were sacrificed and malondialdehyde (MDA, glutathione (GSH, free APAP, and glutathione conjugated of APAP (APAP-GSH were determined in the kidney tissue. Results: GSH depletion and MDA levels significantly (P<0.05 increased in mice treated with either APAP or APAP plus Rebadioside A, respectively in 2 and 6 hours intervals after APAP administration. Significantly (P<0.05 higher levels of free APAP and APAP-GSH levels detected in kidney of mice administrated with APAP plus rebadioside A compared to APAP treated ones. Conclusion: Rebadioside A may be a potential compound in alleviation of APAP-induced oxidative stress in kidney of mice after APAP overdoses.

  19. Attenuation of Biochemical, Haematological and Histological Indices of Alloxan Toxicity in Male Rats by Aqueous Extract of Fadogia agrestis(Schweinf. Ex Hiern Stems

    Directory of Open Access Journals (Sweden)

    Musa Toyin Yakubu

    2015-09-01

    Full Text Available Background: The effects of aqueous extract of Fadogia agrestis stem at the doses of 18, 36, and 72 mg/kg body weight on alloxan-induced toxicity was investigated in Wistar rats. Methods: In total, 35 rats of both sexes (132.80±7.22g were randomized into five groups (A-E: animals in group A received 0.5 ml of distilled water orally on daily basis for 15 days while the alloxanized rats in groups B, C, D and E also received orally 0.5 ml of distilled water and same volume of the extract corresponding to 18, 36, and 72 mg/kg body weight, respectively after which levels of some biomolecules were determined and histological changes evaluated. Results: Administration of alloxan significantly (P0.05 with their respective non-alloxanized distilled water treated control animals in 78% of the parameters investigated. Conclusion: Overall, the aqueous extract of F. agrestis stem attenuated the alloxan treatment related biochemical, haematological and histological changes in the rats with the 72 mg/kg body weight achieving total reversal in 18 out of the 23 parameters investigated.

  20. Stevia-derived compounds attenuate the toxic effects of ectopic lipid accumulation in the liver of obese mice: a transcriptomic and metabolomic study.

    Science.gov (United States)

    Holvoet, Paul; Rull, Anna; García-Heredia, Anabel; López-Sanromà, Sílvia; Geeraert, Benjamine; Joven, Jorge; Camps, Jordi

    2015-03-01

    There is a close interaction between Type 2 Diabetes, obesity and liver disease. We have studied the effects of the two most abundant Stevia-derived steviol glycosides, stevioside and rebaudioside A, and their aglycol derivative steviol on liver steatosis and the hepatic effects of lipotoxicity using a mouse model of obesity and insulin resistance. We treated ob/ob and LDLR-double deficient mice with stevioside (10 mg⋅kg(-1)⋅day-1 p.o., n = 8), rebaudioside A (12 mg⋅kg(-1)⋅day-1 p.o., n = 8), or steviol (5 mg⋅kg(-1)⋅day(-1) p.o., n = 8). We determined their effects on liver steatosis and on the metabolic effects of lipotoxicity by histological analysis, and by combined gene-expression and metabolomic analyses. All compounds attenuated hepatic steatosis. This could be explained by improved glucose metabolism, fat catabolism, bile acid metabolism, and lipid storage and transport. We identified PPARs as important regulators and observed differences in effects on insulin resistance, inflammation and oxidative stress between Stevia-derived compounds. We conclude that Stevia-derived compounds reduce hepatic steatosis to a similar extent, despite differences in effects on glucose and lipid metabolism, and inflammation and oxidative stress. Thus our data show that liver toxicity can be reduced through several pathophysiological changes. Further identification of active metabolites and underlying mechanisms are warranted. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. In vivo toxicity of copper oxide, lead oxide and zinc oxide nanoparticles acting in different combinations and its attenuation with a complex of innocuous bio-protectors.

    Science.gov (United States)

    Minigalieva, Ilzira A; Katsnelson, Boris A; Panov, Vladimir G; Privalova, Larisa I; Varaksin, Anatoly N; Gurvich, Vladimir B; Sutunkova, Marina P; Shur, Vladimir Ya; Shishkina, Ekaterina V; Valamina, Irene E; Zubarev, Ilya V; Makeyev, Oleg H; Meshtcheryakova, Ekaterina Y; Klinova, Svetlana V

    2017-04-01

    Stable suspensions of metal oxide nanoparticles (Me-NPs) obtained by laser ablation of 99.99% pure copper, zinc or lead under a layer of deionized water were used separately, in three binary combinations and a triple combination in two independent experiments on rats. In one of the experiments the rats were instilled with Me-NPs intratracheally (i.t.) (for performing a broncho-alveolar lavage in 24h to estimate the cytological and biochemical indices of the response of the lower airways), while in the other, Me-NPs were repeatedly injected intraperitoneally (i.p.) 18 times during 6 weeks (for estimating the accumulation of corresponding metals in the blood and their excretion with urine and feces and for assessing subchronic intoxication by a large number of functional and morphological indices). Mathematical description of the results from both experiments with the help of the Response Surface Methodology has shown that, as well as in the case of any other binary toxic combinations previously investigated by us, the response of the organism to a simultaneous exposure to any two of the Me-NPs under study is characterized by complex interactions between all possible types of combined toxicity (additivity, subadditivity or superadditivity of unidirectional action and different variants of opposite effects) depending on which effect it is estimated for as well as on the levels of the effect and dose. With any third Me-NP species acting in the background, the type of combined toxicity displayed by the other two may change significantly (as in the earlier described case of a triple combination of soluble metal salts). It is shown that various harmful effects produced by CuO-NP+ZnO-NP+PbO-NP combination may be substantially attenuated by giving rats per os a complex of innocuous bioactive substances theoretically expected to provide a protective integral and/or metal-specific effect during one month before i.t. instillation or during the entire period of i.p. injections

  2. The pharmacokinetic study on the mechanism of toxicity attenuation of rhubarb total free anthraquinone oral colon-specific drug delivery system.

    Science.gov (United States)

    Zhang, Lin; Chang, Jin-hua; Zhang, Bao-qi; Liu, Xi-gang; Liu, Pei; Xue, He-fei; Liu, Li-yan; Fu, Qiang; Zhu, Meng; Liu, Cui-zhe

    2015-07-01

    Rhubarb is commonly used as laxatives in Asian countries, of which anthraquinones are the major active ingredients, but there are an increased number of concerns regarding the nephrotoxicity of anthraquinones. In this study, we compared the pharmacokinetic characteristics of rhubarb anthraquinones in rats after orally administered with rhubarb and rhubarb total free anthraquinone oral colon-specific drug delivery granules (RTFA-OCDD-GN), and then explained why these granules could reduce the nephrotoxicity of anthraquinones when they produced purgative efficacy. A sensitive and reliable high performance liquid chromatography (HPLC) method has been fully validated for simultaneous determination of the five active components of rhubarb, and successfully applied to investigate and compare the remarkable differences in pharmacokinetic study of rhubarb anthraquinones after orally administered with rhubarb and RTFA-OCDD-GN. The results showed that, compared with rhubarb group, the AUC, Cmax, t1/2z and Vz/F of aloe-emodin, rhein, emodin and chrysophanol in rats receiving the RTFA-OCDD-GN were significantly decreased, and the Tmax of the four analytes was prolonged. Moreover, the Tmax of rhein, the Cmax of chrysophanol and emodin all have significant differences (Panthraquinone prototype excretion rates in urine and feces of aloe-emodin, rhein, emodin, chrysophanol and physcion were all increased. These findings suggested that oral colon-specific drug delivery technology made anthraquinone aglycone to colon-specific release after oral administration. This allowed anthraquinones to not only play the corresponding purgative effect but also avoid intestinal absorption and promote excretion. And thereby greatly reduced the nephrotoxicity of rhubarb. The result is a new breakthrough in rhubarb toxicity attenuated research. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Dynamin-Related Protein 1 Inhibitors Protect against Ischemic Toxicity through Attenuating Mitochondrial Ca2+ Uptake from Endoplasmic Reticulum Store in PC12 Cells

    Directory of Open Access Journals (Sweden)

    Ye Tian

    2014-02-01

    Full Text Available Intracellular calcium homeostasis disorder and mitochondrial dysfunction are involved in many acute and chronic brain diseases, including ischemic brain injury. An imbalance in mitochondrial fission and fusion is one of the most important structural abnormalities found in a large number of mitochondrial dysfunction related diseases. Here, we investigated the effects of mitochondrial division inhibitor A (mdivi A and mdivi B, two small molecule inhibitors of mitochondrial fission protein dunamin-related protein 1 (Drp-1, in neuronal injury induced by oxygen-glucose deprivation (OGD in PC12 cells. We found that mdivi A and mdivi B inhibited OGD-induced neuronal injury through attenuating apoptotic cell death. These two inhibitors also preserved mitochondrial function, as evidenced by reduced reactive oxygen species (ROS generation and cytochrome c release, as well as prevented loss of mitochondrial membrane potential (MMP. Moreover, mdivi A and mdivi B significantly suppressed mitochondrial Ca2+ uptake, but had no effect on cytoplasmic Ca2+ after OGD injury. The results of calcium imaging and immunofluorescence staining showed that Drp-1 inhibitors attenuated endoplasmic reticulum (ER Ca2+ release and prevented ER morphological changes induced by OGD. These results demonstrate that Drp-1 inhibitors protect against ischemic neuronal injury through inhibiting mitochondrial Ca2+ uptake from the ER store and attenuating mitochondrial dysfunction.

  4. Vitamin C attenuates biochemical and genotoxic damage in common carp (Cyprinus carpio) upon joint exposure to combined toxic doses of fipronil and buprofezin insecticides.

    Science.gov (United States)

    Ghazanfar, Madiha; Shahid, Sana; Qureshi, Irfan Zia

    2018-03-01

    In the present study, potential protective role of Vitamin C (l-ascorbic acid) was investigated in aquaria acclimated common carp (Cyprinus carpio) following exposure for 96 h to combined toxic doses of fipronil (FP) and buprofezin (BPFN) insecticides in combination (FP: 200 μg/L; 4.57 × 10 -7  mol/L and BPFN: 50 mg/L; 1.64 × 10 -4  mol/L). At end of 96 h exposure, fish were supplemented with low (25 mg/L) and high (50 mg/L) doses of Vitamin C, added once daily to aquaria water for continuous three weeks. Appropriate control groups were run in parallel. Fish behavior was monitored throughout for signs of toxicity. At completion of experiments, liver, kidney, brain and gills were excised for toxicity assessment and possible remediation by the Vitamin C through biochemical determination of reactive oxygen species (ROS), thiobarbituric acid reactive substances or TBARS, reduced glutathione (GSH) and total protein content, levels of catalase (CAT), superoxide dismutase (SOD) and peroxidase (POD), and the Comet assay. Hepatosomatic index (HSI), condition factor (CF), survival rate (SR), and combination index (CI) were also determined. Data were compared statistically at p < 0.05. Results showed significant behavioral and biochemical alterations, and DNA damage in the fish group exposed to FP and BPFN in combination. In fish groups supplemented with Vitamin C following FP and BPFN treatment, significant alleviation in tissue damage and toxic effects was represented by substantial decreases in ROS and TBARS production (p < 0.001), along with a concomitant significant increase in the survival rate, GSH and total protein content, HSI, CF, and activities of SOD, CAT and POD enzymes (p < 0.001). Mean tail length of comet and percent tail DNA decreased significantly (p < 0.001), which indicated amelioration of DNA damage. The study concludes that Vitamin C is an effective remedial treatment against FP and BPFN-induced damage in

  5. α-lipoic acid inhibits oxidative stress in testis and attenuates testicular toxicity in rats exposed to carbimazole during embryonic period

    Directory of Open Access Journals (Sweden)

    P. Prathima

    Full Text Available The aim of this study was to evaluate the probable protective effect of α-lipoic acid against testicular toxicity in rats exposed to carbimazole during the embryonic period. Time-mated pregnant rats were exposed to carbimazole from the embryonic days 9–21. After completion of the gestation period, all the rats were allowed to deliver pups and weaned. At postnatal day 100, F1 male pups were assessed for the selected reproductive endpoints. Gestational exposure to carbimazole decreased the reproductive organ indices, testicular daily sperm count, epididymal sperm variables viz., sperm count, viable sperm, motile sperm and HOS-tail coiled sperms. Significant decrease in the activity levels of 3β- and 17β-hydroxysteroid dehydrogenases and expression of StAR mRNA levels with a significant increase in the total cholesterol levels were observed in the testis of experimental rats over the controls. These events were also accompanied by a significant reduction in the serum testosterone levels in CBZ exposed rats, indicating reduced steroidogenesis. In addition, the deterioration of the testicular architecture and reduced fertility ability were noticed in the carbimazole exposed rats. Significant reduction in the activity levels of superoxide dismutase, catalase, glutathione reductase, glutathione peroxidase and reduced glutathione content with a significant increase in the levels of lipid peroxidation were observed in the testis of carbimazole exposed rats over the controls. Conversely, supplementation of α-lipoic acid (70 mg/Kg bodyweight ameliorated the male reproductive health in rats exposed to carbimazole during the embryonic period as evidenced by enhanced reproductive organ weights, selected sperm variables, testicular steroidogenesis, and testicular enzymatic and non-enzymatic antioxidants. To conclude, diminished testicular antioxidant balance associated with reduced spermatogenesis and steroidogenesis might be responsible

  6. Mesenchymal stem cell transplantation attenuates blood brain barrier damage and neuroinflammation and protects dopaminergic neurons against MPTP toxicity in the substantia nigra in a model of Parkinson's disease.

    Science.gov (United States)

    Chao, Yin Xia; He, Bei Ping; Tay, Samuel Sam Wah

    2009-11-30

    Immunomodulatory effects of transplanted mesenchymal stem cells (MSCs) in the treatment of Parkinson's disease were studied in the MPTP-induced mouse model. MPTP treatment induced a significant loss of dopaminergic neurons, decreased expressions of claudin 1, claudin 5 and occludin in the substantia nigra compacta (SNc), and functional damage of the blood brain barrier (BBB). Our study further discovered that infiltration of MBLs into the brain to bind with microglia was detected in the SNc of MPTP-treated mice, suggesting that the BBB compromise and MBL infiltration might be involved in the pathogenesis of MPTP-induced PD. In addition, MPTP treatment also increased the expression of mannose-binding lectins (MBLs) in the liver tissue. Intravenous transplantation of MSCs into MPTP-treated mice led to recovery of BBB integrity, suppression of MBL infiltration at SNc and MBL expression in the liver, suppression of microglial activation and prevention of dopaminergic neuron death. No transplanted MSCs were observed to differentiate into dopaminergic neurons, while the MSCs migrated into the SNc and released TGF-beta1 there. Therefore, intravenous transplantation of MSCs which protect dopaminergic neurons from MPTP toxicity may be engaged in anyone or a combination of these mechanisms: repair of the BBB, reduction of MBL in the brain, inhibition of microglial cytotoxicity, and direct protection of dopaminergic neurons.

  7. ALA/LA ameliorates glucose toxicity on HK-2 cells by attenuating oxidative stress and apoptosis through the ROS/p38/TGF-β1 pathway.

    Science.gov (United States)

    Jiang, Mingxia; Zhang, Haifen; Zhai, Lijie; Ye, Bianliang; Cheng, Yin; Zhai, Chengkai

    2017-11-16

    Growing evidence indicates that oxidative stress (OS) plays a pivotal role in Diabetic nephropathy (DN). In a previous study we demonstrated that ALA/LA protected HK-2 cells against high glucose-induced cytotoxicity. So we aimed to establish the glucose injury model of HK-2 cells and investigate the beneficial effects of ALA/LA on high glucose-induced excessive production of TGF-β1 and the possible mechanisms mediating the effects. The expression of OS markers in high glucose-induced HK-2 cells treated with ALA/LA., including the antioxidant enzymes and reactive oxygen species (ROS) production, as well as the apoptosis rate were assayed by ELISA and flow cytometry. The p38/transforming growth factor β 1 (TGF-β 1 ) signal pathway were measured by real-time RT-PCR and western blot. The modeling condition of glucose toxicity on HK-2 cells was at the glucose concentration of 40.9 mM. ALA/LA can significantly increase the activities of antioxidant enzymes and decrease ROS production stimulated by high glucose. The study also found that ALA/LA caused a decrease in the apoptosis rate and TGF-β 1 level of HK-2 cells under high glucose stress through the ROS/p38 pathway. ALA/LA exerts protective effects in vitro through inhibition of ROS generation, down regulation of the activation of the p38MAPK pathway and the expression of TGF-β 1 in HK-2 cells.

  8. attenuates the testicular toxicity associated with experimental ...

    African Journals Online (AJOL)

    SERVER

    2007-06-18

    Jun 18, 2007 ... heat which brings about oxidative stress on the semi- niferous tubules. It is also ... MATERIALS AND METHODS. Chemicals. Vitamin E ... transferred into two changes of molten paraffin wax for 20 min each in an oven at 57°C.

  9. Tracer attenuation in groundwater

    Science.gov (United States)

    Cvetkovic, Vladimir

    2011-12-01

    The self-purifying capacity of aquifers strongly depends on the attenuation of waterborne contaminants, i.e., irreversible loss of contaminant mass on a given scale as a result of coupled transport and transformation processes. A general formulation of tracer attenuation in groundwater is presented. Basic sensitivities of attenuation to macrodispersion and retention are illustrated for a few typical retention mechanisms. Tracer recovery is suggested as an experimental proxy for attenuation. Unique experimental data of tracer recovery in crystalline rock compare favorably with the theoretical model that is based on diffusion-controlled retention. Non-Fickian hydrodynamic transport has potentially a large impact on field-scale attenuation of dissolved contaminants.

  10. Introducing Toxics

    OpenAIRE

    David C. Bellinger

    2013-01-01

    With this inaugural issue, Toxics begins its life as a peer-reviewed, open access journal focusing on all aspects of toxic chemicals. We are interested in publishing papers that present a wide range of perspectives on toxicants and naturally occurring toxins, including exposure, biomarkers, kinetics, biological effects, fate and transport, treatment, and remediation. Toxics differs from many other journals in the absence of a page or word limit on contributions, permitting authors to present ...

  11. Quercitrin from Toona sinensis (Juss. M.Roem. Attenuates Acetaminophen-Induced Acute Liver Toxicity in HepG2 Cells and Mice through Induction of Antioxidant Machinery and Inhibition of Inflammation

    Directory of Open Access Journals (Sweden)

    Van-Long Truong

    2016-07-01

    Full Text Available Quercitrin is found in many kinds of vegetables and fruits, and possesses various bioactive properties. The aim of the present study was to elucidate hepatoprotective mechanisms of quercitrin isolated from Toona sinensis (Juss. M.Roem. (syn. Cedrela sinensis Juss., using acetaminophen (APAP-treated HepG2 cell and animal models. In an in vitro study, quercitrin suppressed the production of reactive oxygen species and enhanced expression of nuclear factor E2-related factor 2 (Nrf2, activity of antioxidant response element (ARE-reporter gene, and protein levels of NADPH: quinone oxidoreductase 1 (NQO1, catalase (CAT, glutathione peroxidase (GPx, and superoxide dismutase 2 (SOD-2 in APAP-treated HepG2 cells. In an in vivo study, Balb/c mice were orally administered with 10 or 50 mg/kg of quercitrin for 7 days and followed by the injection with single dose of 300 mg/kg APAP. Quercitrin decreased APAP-caused elevation of alanine aminotransferase and aspartate aminotransferase levels, liver necrosis, the expression of pro-inflammatory factors including inducible nitric oxide synthase, cyclooxygenase 2 and inerleukin-1β, and phosphorylation of kinases including c-Jun N-terminal kinase and p38. Quercitrin restored protein levels of Nrf2, NQO1 and activities and expressions of CAT, GPx, SOD-2. The results suggested that quercitrin attenuates APAP-induced liver damage by the activation of defensive genes and the inhibition of pro-inflammatory genes via the suppressions of JNK and p38 signaling.

  12. Toxic Elements

    DEFF Research Database (Denmark)

    Hajeb, Parvaneh; Shakibazadeh, Shahram; Sloth, Jens Jørgen

    2016-01-01

    Food is considered the main source of toxic element (arsenic, cadmium, lead, and mercury) exposure to humans, and they can cause major public health effects. In this chapter, we discuss the most important sources for toxic element in food and the foodstuffs which are significant contributors to h...

  13. Attenuation correction for SPECT

    International Nuclear Information System (INIS)

    Hosoba, Minoru

    1986-01-01

    Attenuation correction is required for the reconstruction of a quantitative SPECT image. A new method for detecting body contours, which are important for the correction of tissue attenuation, is presented. The effect of body contours, detected by the newly developed method, on the reconstructed images was evaluated using various techniques for attenuation correction. The count rates in the specified region of interest in the phantom image by the Radial Post Correction (RPC) method, the Weighted Back Projection (WBP) method, Chang's method were strongly affected by the accuracy of the contours, as compared to those by Sorenson's method. To evaluate the effect of non-uniform attenuators on the cardiac SPECT, computer simulation experiments were performed using two types of models, the uniform attenuator model (UAM) and the non-uniform attenuator model (NUAM). The RPC method showed the lowest relative percent error (%ERROR) in UAM (11 %). However, 20 to 30 percent increase in %ERROR was observed for NUAM reconstructed with the RPC, WBP, and Chang's methods. Introducing an average attenuation coefficient (0.12/cm for Tc-99m and 0.14/cm for Tl-201) in the RPC method decreased %ERROR to the levels for UAM. Finally, a comparison between images, which were obtained by 180 deg and 360 deg scans and reconstructed from the RPC method, showed that the degree of the distortion of the contour of the simulated ventricles in the 180 deg scan was 15 % higher than that in the 360 deg scan. (Namekawa, K.)

  14. Introducing Toxics

    Directory of Open Access Journals (Sweden)

    David C. Bellinger

    2013-04-01

    Full Text Available With this inaugural issue, Toxics begins its life as a peer-reviewed, open access journal focusing on all aspects of toxic chemicals. We are interested in publishing papers that present a wide range of perspectives on toxicants and naturally occurring toxins, including exposure, biomarkers, kinetics, biological effects, fate and transport, treatment, and remediation. Toxics differs from many other journals in the absence of a page or word limit on contributions, permitting authors to present their work in as much detail as they wish. Toxics will publish original research papers, conventional reviews, meta-analyses, short communications, theoretical papers, case reports, commentaries and policy perspectives, and book reviews (Book reviews will be solicited and should not be submitted without invitation. Toxins and toxicants concern individuals from a wide range of disciplines, and Toxics is interested in receiving papers that represent the full range of approaches applied to their study, including in vitro studies, studies that use experimental animal or non-animal models, studies of humans or other biological populations, and mathematical modeling. We are excited to get underway and look forward to working with authors in the scientific and medical communities and providing them with a novel venue for sharing their work. [...

  15. Landing gear noise attenuation

    Science.gov (United States)

    Moe, Jeffrey W. (Inventor); Whitmire, Julia (Inventor); Kwan, Hwa-Wan (Inventor); Abeysinghe, Amal (Inventor)

    2011-01-01

    A landing gear noise attenuator mitigates noise generated by airframe deployable landing gear. The noise attenuator can have a first position when the landing gear is in its deployed or down position, and a second position when the landing gear is in its up or stowed position. The noise attenuator may be an inflatable fairing that does not compromise limited space constraints associated with landing gear retraction and stowage. A truck fairing mounted under a truck beam can have a compliant edge to allow for non-destructive impingement of a deflected fire during certain conditions.

  16. Antimony Toxicity

    Directory of Open Access Journals (Sweden)

    Shyam Sundar

    2010-12-01

    Full Text Available Antimony toxicity occurs either due to occupational exposure or during therapy. Occupational exposure may cause respiratory irritation, pneumoconiosis, antimony spots on the skin and gastrointestinal symptoms. In addition antimony trioxide is possibly carcinogenic to humans. Improvements in working conditions have remarkably decreased the incidence of antimony toxicity in the workplace. As a therapeutic, antimony has been mostly used for the treatment of leishmaniasis and schistosomiasis. The major toxic side-effects of antimonials as a result of therapy are cardiotoxicity (~9% of patients and pancreatitis, which is seen commonly in HIV and visceral leishmaniasis co-infections. Quality control of each batch of drugs produced and regular monitoring for toxicity is required when antimonials are used therapeutically.

  17. Antimony Toxicity

    OpenAIRE

    Sundar, Shyam; Chakravarty, Jaya

    2010-01-01

    Antimony toxicity occurs either due to occupational exposure or during therapy. Occupational exposure may cause respiratory irritation, pneumoconiosis, antimony spots on the skin and gastrointestinal symptoms. In addition antimony trioxide is possibly carcinogenic to humans. Improvements in working conditions have remarkably decreased the incidence of antimony toxicity in the workplace. As a therapeutic, antimony has been mostly used for the treatment of leishmaniasis and schistosomiasis. The...

  18. Oxygen toxicity

    Directory of Open Access Journals (Sweden)

    C. A. van der Westhuizen

    1990-07-01

    Full Text Available Oxygen has been discovered about 200 years ago. Since then the vital physiological involvement of oxygen in various biologi­cal processes, mainly energy production, has been established. However, in the body molecular oxygen can be converted to toxic oxygen metabolites such as superoxide anion, hydrogen peroxide, the hydroxyl radical and singlet oxygen. These toxic metabolites are produced mainly in the mitochondria, plasma membranes and endoplasmic reticulum.

  19. Radionuclide toxicity

    International Nuclear Information System (INIS)

    Galle, P.

    1982-01-01

    The aim of this symposium was to review the radionuclide toxicity problems. Five topics were discussed: (1) natural and artificial radionuclides (origin, presence or emission in the environment, human irradiation); (2) environmental behaviour of radionuclides and transfer to man; (3) metabolism and toxicity of radionuclides (radioiodine, strontium, rare gas released from nuclear power plants, ruthenium-activation metals, rare earths, tritium, carbon 14, plutonium, americium, curium and einsteinium, neptunium, californium, uranium) cancerogenous effects of radon 222 and of its danghter products; (4) comparison of the hazards of various types of energy; (5) human epidemiology of radionuclide toxicity (bone cancer induction by radium, lung cancer induction by radon daughter products, liver cancer and leukaemia following the use of Thorotrast, thyroid cancer; other site of cancer induction by radionuclides) [fr

  20. Radiofrequency attenuator and method

    Science.gov (United States)

    Warner, Benjamin P [Los Alamos, NM; McCleskey, T Mark [Los Alamos, NM; Burrell, Anthony K [Los Alamos, NM; Agrawal, Anoop [Tucson, AZ; Hall, Simon B [Palmerston North, NZ

    2009-01-20

    Radiofrequency attenuator and method. The attenuator includes a pair of transparent windows. A chamber between the windows is filled with molten salt. Preferred molten salts include quarternary ammonium cations and fluorine-containing anions such as tetrafluoroborate (BF.sub.4.sup.-), hexafluorophosphate (PF.sub.6.sup.-), hexafluoroarsenate (AsF.sub.6.sup.-), trifluoromethylsulfonate (CF.sub.3SO.sub.3.sup.-), bis(trifluoromethylsulfonyl)imide ((CF.sub.3SO.sub.2).sub.2N.sup.-), bis(perfluoroethylsulfonyl)imide ((CF.sub.3CF.sub.2SO.sub.2).sub.2N.sup.-) and tris(trifluoromethylsulfonyl)methide ((CF.sub.3SO.sub.2).sub.3C.sup.-). Radicals or radical cations may be added to or electrochemically generated in the molten salt to enhance the RF attenuation.

  1. Attenuation coefficients of soils

    International Nuclear Information System (INIS)

    Martini, E.; Naziry, M.J.

    1989-01-01

    As a prerequisite to the interpretation of gamma-spectrometric in situ measurements of activity concentrations of soil radionuclides the attenuation of 60 to 1332 keV gamma radiation by soil samples varying in water content and density has been investigated. A useful empirical equation could be set up to describe the dependence of the mass attenuation coefficient upon photon energy for soil with a mean water content of 10%, with the results comparing well with data in the literature. The mean density of soil in the GDR was estimated at 1.6 g/cm 3 . This value was used to derive the linear attenuation coefficients, their range of variation being 10%. 7 figs., 5 tabs. (author)

  2. Oral vaccination with attenuated Salmonella choleraesuis C500 ...

    African Journals Online (AJOL)

    user

    Marshall, 1983), and well known as the major gastro- duodenal ... The CagA is encoded in a pathogenicity island known as 'Cag PAI' and is .... HindIII to release the CagA fragment. The purified .... vaccine strain attenuated by chemical methods, which is .... pylori antigens is achieved using a non-toxic mutant of E. coli heat-.

  3. NATURAL ATTENUATION OF COPPER IN SOILS AND SOIL MINERALS - II

    Science.gov (United States)

    The bioabailability and toxicity of Cu in soils is controlled by a number of soil properties and processes. Some of these such as pH, adsorption/desorption and competition with beneficial cations have been extensively studied. However, the effects of natural attenuation (or aging...

  4. Computer-controlled attenuator.

    Science.gov (United States)

    Mitov, D; Grozev, Z

    1991-01-01

    Various possibilities for applying electronic computer-controlled attenuators for the automation of physiological experiments are considered. A detailed description is given of the design of a 4-channel computer-controlled attenuator, in two of the channels of which the output signal can change by a linear step, in the other two channels--by a logarithmic step. This, together with the existence of additional programmable timers, allows to automate a wide range of studies in different spheres of physiology and psychophysics, including vision and hearing.

  5. Predicting toxic heavy metal movements in upper Sanyati catchment ...

    African Journals Online (AJOL)

    Water samples from boreholes located in areas where mining, mineral processing and agricultural activities were dominant, yielded the highest values of toxic heavy metals. Dilution Attenuation Factor (DAF) for each toxic heavy metal was calculated to observe metal behaviour along the contaminant path for each season.

  6. Natural attenuation of herbicides

    DEFF Research Database (Denmark)

    Tuxen, Nina; Højberg, Anker Lajer; Broholm, Mette Martina

    2002-01-01

    A field injection experiment in a sandy, aerobic aquifer showed that two phenoxy acids MCPP (mecoprop) and dichlorprop were degraded within I in downgradient of the injection wells after an apparent lag period. The plume development and microbial measurements indicated that microbial growth gover....... The observations may be important for application of natural attenuation as a remedy in field scale systems....

  7. Measured attenuation correction methods

    International Nuclear Information System (INIS)

    Ostertag, H.; Kuebler, W.K.; Doll, J.; Lorenz, W.J.

    1989-01-01

    Accurate attenuation correction is a prerequisite for the determination of exact local radioactivity concentrations in positron emission tomography. Attenuation correction factors range from 4-5 in brain studies to 50-100 in whole body measurements. This report gives an overview of the different methods of determining the attenuation correction factors by transmission measurements using an external positron emitting source. The long-lived generator nuclide 68 Ge/ 68 Ga is commonly used for this purpose. The additional patient dose from the transmission source is usually a small fraction of the dose due to the subsequent emission measurement. Ring-shaped transmission sources as well as rotating point or line sources are employed in modern positron tomographs. By masking a rotating line or point source, random and scattered events in the transmission scans can be effectively suppressed. The problems of measured attenuation correction are discussed: Transmission/emission mismatch, random and scattered event contamination, counting statistics, transmission/emission scatter compensation, transmission scan after administration of activity to the patient. By using a double masking technique simultaneous emission and transmission scans become feasible. (orig.)

  8. Alpha lipoic acid attenuates high-fructose-induced pancreatic toxicity.

    Science.gov (United States)

    Topsakal, Senay; Ozmen, Ozlem; Cankara, Fatma Nihan; Yesilot, Sukriye; Bayram, Dilek; Genç Özdamar, Nilüfer; Kayan, Sümeyra

    2016-01-01

    Chronic consumption of high-fructose corn syrup (HFCS) causes several problems such as insulin resistance. The goal of the study was to investigate pancreatic damage induced by chronic HFCS consumption and the protective effects of alpha lipoic acid (ALA) on pancreatic cells. Wistar Albino, 4-month-old, female rats weighing 250-300 g were randomly distributed into three groups, each containing eight rats. The study included an HFCS group, an HFCS + ALA-administered group and a control group (CON). The prepared 30% solution of HFCS (F30) (24% fructose, 28% dextrose) was added to the drinking water for 10 weeks. ALA treatment was begun 4 weeks after the first HFCS administration (100 mg/kg/oral, last 6 weeks). Rats were anaesthetised and euthanised by cervical dislocation 24 h after the last ALA administration. Blood samples for biochemical tests (amylase, lipase, malondialdehyde (MDA) and catalase (CAT)) and tissue samples for histopathological and immunohistochemical examinations (caspase-3, insulin and glucagon) were collected. Comparing the control and HFCS groups, serum glucose (150.92 ± 39.77 and 236.50 ± 18.28, respectively, p < 0.05), amylase (2165.00 ± 150.76 and 3027.66 ± 729.19, respectively, p < 0.01), lipase (5.58 ± 2.22 and 11.51 ± 2.74, respectively, p < 0.01) and pancreatic tissue MDA (0.0167 ± 0.004 and 0.0193 ± 0.006, respectively, p < 0.05) levels were increased, whereas tissue CAT (0.0924 ± 0.029 and 0.0359 ± 0.023, respectively, p < 0.05) activity decreased in the HFCS group significantly. Histopathological examination revealed degenerative and necrotic changes in Langerhans islet cells and slight inflammatory cell infiltration in pancreatic tissue in the HFCS group. Immunohistochemically there was a significant decrease in insulin (2.85 ± 0.37 and 0.87 ± 0.64, respectively, p < 0.001) and glucagon (2.71 ± 0.48 and 1.00 ± 0.75, respectively, p < 0.001) secreting cell scores, whereas a greater increase in caspase-3 (0.14 ± 0.37 and 1.00 ± 0.75, respectively, p < 0.05) expression was seen in this group compared with the controls. In the ALA-treated group, all of these pathologic conditions were improved. This study indicated HFCS induced pancreatic lesions, but ALA had ameliorative effects. Copyright © 2016 IAP and EPC. Published by Elsevier B.V. All rights reserved.

  9. Photon attenuation by intensifying screens

    International Nuclear Information System (INIS)

    Holje, G.

    1983-01-01

    The photon attenuation by intensifying screens of different chemical composition has been determined. The attenuation of photons between 20 keV and 120 keV was measured by use of a multi-channel analyzer and a broad bremsstrahlung distribution. The attenuation by the intensifying screens was hereby determined simultaneously at many different monoenergetic photon energies. Experimentally determined attenuations were found to agree well with attenuation calculated from mass attenuation coefficients. The attenuation by the screens was also determined at various bremsstrahlung distributions, simulating those occurring behind the patient in various diagnostic X-ray examinations. The high attenuation in some of the intensifying screens form the basis for an analysis of the construction of asymmetric screen pairs. Single screen systems are suggested as a favourable alternative to thick screen pair systems. (Author)

  10. Enhanced Attenuation: Chlorinated Organics

    Science.gov (United States)

    2008-04-01

    attenuation capacity of the aquifer downgradient from the source (e.g., permeable reactive barriers or phytoremediation ) Selection of EA remedies should be...prevalence and/or mobility of nitrate and sulfate compounds and/or metals such as iron, manganese, chromium, copper, and arsenic . Furthermore, in...ranging from very aggressive source destruction and removal methods to less energy-intensive methods, such as phytoremediation . In many cases, it

  11. Toxic shock syndrome

    Science.gov (United States)

    Staphylococcal toxic shock syndrome; Toxic shock-like syndrome; TSLS ... Toxic shock syndrome is caused by a toxin produced by some types of staphylococcus bacteria. A similar problem, called toxic shock- ...

  12. Human Toxicity

    DEFF Research Database (Denmark)

    Jolliet, Olivier; Fantke, Peter

    2015-01-01

    all chemicals and impact pathways characterizes the contribution of each factor to the total variation of 10–12 orders of magnitude in impacts per kg across all chemicals. This large variation between characterisation factors for different chemicals as well as the 3 orders of magnitude uncertainty....... As a whole, the assessment of toxicity in LCA has progressed on a very sharp learning curve during the past 20 years. This rapid progression is expected to continue in the coming years, focusing more on direct exposure of workers to chemicals during manufacturing and of consumers during product use...

  13. Control algorithms for dynamic attenuators

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, Scott S., E-mail: sshsieh@stanford.edu [Department of Radiology, Stanford University, Stanford, California 94305 and Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States); Pelc, Norbert J. [Department of Radiology, Stanford University, Stanford California 94305 and Department of Bioengineering, Stanford University, Stanford, California 94305 (United States)

    2014-06-15

    Purpose: The authors describe algorithms to control dynamic attenuators in CT and compare their performance using simulated scans. Dynamic attenuators are prepatient beam shaping filters that modulate the distribution of x-ray fluence incident on the patient on a view-by-view basis. These attenuators can reduce dose while improving key image quality metrics such as peak or mean variance. In each view, the attenuator presents several degrees of freedom which may be individually adjusted. The total number of degrees of freedom across all views is very large, making many optimization techniques impractical. The authors develop a theory for optimally controlling these attenuators. Special attention is paid to a theoretically perfect attenuator which controls the fluence for each ray individually, but the authors also investigate and compare three other, practical attenuator designs which have been previously proposed: the piecewise-linear attenuator, the translating attenuator, and the double wedge attenuator. Methods: The authors pose and solve the optimization problems of minimizing the mean and peak variance subject to a fixed dose limit. For a perfect attenuator and mean variance minimization, this problem can be solved in simple, closed form. For other attenuator designs, the problem can be decomposed into separate problems for each view to greatly reduce the computational complexity. Peak variance minimization can be approximately solved using iterated, weighted mean variance (WMV) minimization. Also, the authors develop heuristics for the perfect and piecewise-linear attenuators which do not requirea priori knowledge of the patient anatomy. The authors compare these control algorithms on different types of dynamic attenuators using simulated raw data from forward projected DICOM files of a thorax and an abdomen. Results: The translating and double wedge attenuators reduce dose by an average of 30% relative to current techniques (bowtie filter with tube current

  14. Control algorithms for dynamic attenuators

    International Nuclear Information System (INIS)

    Hsieh, Scott S.; Pelc, Norbert J.

    2014-01-01

    Purpose: The authors describe algorithms to control dynamic attenuators in CT and compare their performance using simulated scans. Dynamic attenuators are prepatient beam shaping filters that modulate the distribution of x-ray fluence incident on the patient on a view-by-view basis. These attenuators can reduce dose while improving key image quality metrics such as peak or mean variance. In each view, the attenuator presents several degrees of freedom which may be individually adjusted. The total number of degrees of freedom across all views is very large, making many optimization techniques impractical. The authors develop a theory for optimally controlling these attenuators. Special attention is paid to a theoretically perfect attenuator which controls the fluence for each ray individually, but the authors also investigate and compare three other, practical attenuator designs which have been previously proposed: the piecewise-linear attenuator, the translating attenuator, and the double wedge attenuator. Methods: The authors pose and solve the optimization problems of minimizing the mean and peak variance subject to a fixed dose limit. For a perfect attenuator and mean variance minimization, this problem can be solved in simple, closed form. For other attenuator designs, the problem can be decomposed into separate problems for each view to greatly reduce the computational complexity. Peak variance minimization can be approximately solved using iterated, weighted mean variance (WMV) minimization. Also, the authors develop heuristics for the perfect and piecewise-linear attenuators which do not requirea priori knowledge of the patient anatomy. The authors compare these control algorithms on different types of dynamic attenuators using simulated raw data from forward projected DICOM files of a thorax and an abdomen. Results: The translating and double wedge attenuators reduce dose by an average of 30% relative to current techniques (bowtie filter with tube current

  15. Control algorithms for dynamic attenuators.

    Science.gov (United States)

    Hsieh, Scott S; Pelc, Norbert J

    2014-06-01

    The authors describe algorithms to control dynamic attenuators in CT and compare their performance using simulated scans. Dynamic attenuators are prepatient beam shaping filters that modulate the distribution of x-ray fluence incident on the patient on a view-by-view basis. These attenuators can reduce dose while improving key image quality metrics such as peak or mean variance. In each view, the attenuator presents several degrees of freedom which may be individually adjusted. The total number of degrees of freedom across all views is very large, making many optimization techniques impractical. The authors develop a theory for optimally controlling these attenuators. Special attention is paid to a theoretically perfect attenuator which controls the fluence for each ray individually, but the authors also investigate and compare three other, practical attenuator designs which have been previously proposed: the piecewise-linear attenuator, the translating attenuator, and the double wedge attenuator. The authors pose and solve the optimization problems of minimizing the mean and peak variance subject to a fixed dose limit. For a perfect attenuator and mean variance minimization, this problem can be solved in simple, closed form. For other attenuator designs, the problem can be decomposed into separate problems for each view to greatly reduce the computational complexity. Peak variance minimization can be approximately solved using iterated, weighted mean variance (WMV) minimization. Also, the authors develop heuristics for the perfect and piecewise-linear attenuators which do not require a priori knowledge of the patient anatomy. The authors compare these control algorithms on different types of dynamic attenuators using simulated raw data from forward projected DICOM files of a thorax and an abdomen. The translating and double wedge attenuators reduce dose by an average of 30% relative to current techniques (bowtie filter with tube current modulation) without

  16. Ultrasonic attenuation in superconducting zinc

    International Nuclear Information System (INIS)

    Auluck, S.

    1978-01-01

    The differences in the Zn ultrasonic attenuation data of different workers are analyzed. The superconducting energy gaps deduced from our analysis of the ultrasonic-attenuation data of Cleavelin and Marshall are consistent with the gaps deduced from the knowledge of the Fermi surface and the electron-phonon mass enhancement factor

  17. Unusual lipid structures selectively reduce the toxicity of amphotericin B

    International Nuclear Information System (INIS)

    Janoff, A.S.; Boni, L.T.; Popescu, M.C.

    1988-01-01

    Ribbon-like structures result when amphotericin B interacts with lipid in an aqueous environment. At high ratios of amphotericin to lipid these structures, which are lipid-stabilized amphotericin aggregates, become prevalent resulting in a dramatic attenuation of amphotericin-mediated mammalian cell, but not fungal cell, toxicity. Studies utilizing freeze-etch electron microscopy, differential scanning calorimetry, 31 P NMR, x-ray diffraction, and optical spectroscopy revealed that this toxicity attenuation is related to the macromolecular structure of the complexes in a definable fashion. It is likely that amphotericin in this specific form will have a much improved therapeutic utility

  18. Distributed Structure Searchable Toxicity

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Distributed Structure Searchable Toxicity (DSSTox) online resource provides high quality chemical structures and annotations in association with toxicity data....

  19. Engineering a Light-Attenuating Artificial Iris.

    Science.gov (United States)

    Shareef, Farah J; Sun, Shan; Kotecha, Mrignayani; Kassem, Iris; Azar, Dimitri; Cho, Michael

    2016-04-01

    Discomfort from light exposure leads to photophobia, glare, and poor vision in patients with congenital or trauma-induced iris damage. Commercial artificial iris lenses are static in nature to provide aesthetics without restoring the natural iris's dynamic response to light. A new photo-responsive artificial iris was therefore developed using a photochromic material with self-adaptive light transmission properties and encased in a transparent biocompatible polymer matrix. The implantable artificial iris was designed and engineered using Photopia, a class of photo-responsive materials (termed naphthopyrans) embedded in polyethylene. Photopia was reshaped into annular disks that were spin-coated with polydimethylsiloxane (PDMS) to form our artificial iris lens of controlled thickness. Activated by UV and blue light in approximately 5 seconds with complete reversal in less than 1 minute, the artificial iris demonstrates graded attenuation of up to 40% of visible and 60% of UV light. There optical characteristics are suitable to reversibly regulate the incident light intensity. In vitro cell culture experiments showed up to 60% cell death within 10 days of exposure to Photopia, but no significant cell death observed when cultured with the artificial iris with protective encapsulation. Nuclear magnetic resonance spectroscopy confirmed these results as there was no apparent leakage of potentially toxic photochromic material from the ophthalmic device. Our artificial iris lens mimics the functionality of the natural iris by attenuating light intensity entering the eye with its rapid reversible change in opacity and thus potentially providing an improved treatment option for patients with iris damage.

  20. Agmatine attenuates silica-induced pulmonary fibrosis.

    Science.gov (United States)

    El-Agamy, D S; Sharawy, M H; Ammar, E M

    2014-06-01

    There is a large body of evidence that nitric oxide (NO) formation is implicated in mediating silica-induced pulmonary fibrosis. As a reactive free radical, NO may not only contribute to lung parenchymal tissue injury but also has the ability to combine with superoxide and form a highly reactive toxic species peroxynitrite that can induce extensive cellular toxicity in the lung tissues. This study aimed to explore the effect of agmatine, a known NO synthase inhibitor, on silica-induced pulmonary fibrosis in rats. Male Sprague Dawley rats were treated with agmatine for 60 days following a single intranasal instillation of silica suspension (50 mg in 0.1 ml saline/rat). The results revealed that agmatine attenuated silica-induced lung inflammation as it decreased the lung wet/dry weight ratio, protein concentration, and the accumulation of the inflammatory cells in the bronchoalveolar lavage fluid. Agmatine showed antifibrotic activity as it decreased total hydroxyproline content of the lung and reduced silica-mediated lung inflammation and fibrosis in lung histopathological specimen. In addition, agmatine significantly increased superoxide dismutase (p Agmatine also reduced silica-induced overproduction of pulmonary nitrite/nitrate as well as tumor necrosis factor α. Collectively, these results demonstrate the protective effects of agmatine against the silica-induced lung fibrosis that may be attributed to its ability to counteract the NO production, lipid peroxidation, and regulate cytokine effects. © The Author(s) 2014.

  1. Subsurface Contaminant Focus Area: Monitored Natural Attenuation (MNA)--Programmatic, Technical, and Regulatory Issues

    Energy Technology Data Exchange (ETDEWEB)

    Krupka, Kenneth M.; Martin, Wayne J.

    2001-07-23

    Natural attenuation processes are commonly used for remediation of contaminated sites. A variety of natural processes occur without human intervention at all sites to varying rates and degrees of effectiveness to attenuate (decrease) the mass, toxicity, mobility, volume, or concentration of organic and inorganic contaminants in soil, groundwater, and surface water systems. The objective of this review is to identify potential technical investments to be incorporated in the Subsurface Contaminant Focus Area Strategic Plan for monitored natural attenuation. When implemented, the technical investments will help evaluate and implement monitored natural attenuation as a remediation option at DOE sites. The outcome of this review is a set of conclusions and general recommendations regarding research needs, programmatic guidance, and stakeholder issues pertaining to monitored natural attenuation for the DOE complex.

  2. Toxicity alarm: Case history

    International Nuclear Information System (INIS)

    Hogan, D.; Retallack, J.

    1993-01-01

    In late fall 1991, the Novacor petrochemical plant near Joffre, Alberta experienced a toxicity alarm, the first since its startup 14 years ago. Fish exposed to a normal toxicity test were stressed within 2 h and showed 100% mortality after 24 h. A history of the events leading up to, during, and after the toxicity alarm is presented. The major effluent sources were three cooling water systems. Although these sources are well characterized, the event causes were not immediately clear. Initial toxic screening indicated that one was very toxic, another moderately toxic, and the third not toxic at all. All three systems utilized the same chemical treatment program to avoid fouling: stabilized phosphates with minor variants. The most toxic of the cooling systems operated at 10-12 cycles, had three chemicals for biocide control, and had three makeup streams. Toxic and nontoxic system characteristics were compared. An in-depth modified toxicity identification and evaluation program was then performed to identify and evaluate the cause of the toxicity alarm for future prevention. The most probable causes of toxicity were identified by elimination. The combination of high numbers of cycles, hydrocarbons in the makeup water, and bromine added as an antifoulant resulted in formation of aromatic bromamines which are capable of causing the toxic condition experienced. 2 tabs

  3. Attenuation in Superconducting Circular Waveguides

    Directory of Open Access Journals (Sweden)

    K. H. Yeap

    2016-09-01

    Full Text Available We present an analysis on wave propagation in superconducting circular waveguides. In order to account for the presence of quasiparticles in the intragap states of a superconductor, we employ the characteristic equation derived from the extended Mattis-Bardeen theory to compute the values of the complex conductivity. To calculate the attenuation in a circular waveguide, the tangential fields at the boundary of the wall are first matched with the electrical properties (which includes the complex conductivity of the wall material. The matching of fields with the electrical properties results in a set of transcendental equations which is able to accurately describe the propagation constant of the fields. Our results show that although the attenuation in the superconducting waveguide above cutoff (but below the gap frequency is finite, it is considerably lower than that in a normal waveguide. Above the gap frequency, however, the attenuation in the superconducting waveguide increases sharply. The attenuation eventually surpasses that in a normal waveguide. As frequency increases above the gap frequency, Cooper pairs break into quasiparticles. Hence, we attribute the sharp rise in attenuation to the increase in random collision of the quasiparticles with the lattice structure.

  4. Toxic substances handbook

    Science.gov (United States)

    Junod, T. L.

    1979-01-01

    Handbook, published in conjunction with Toxic Substances Alert Program at NASA Lewis Research Center, profiles 187 toxic chemicals in their relatively pure states and include 27 known or suspected carcinogens.

  5. Engineering a Light-Attenuating Artificial Iris

    Science.gov (United States)

    Shareef, Farah J.; Sun, Shan; Kotecha, Mrignayani; Kassem, Iris; Azar, Dimitri; Cho, Michael

    2016-01-01

    Purpose Discomfort from light exposure leads to photophobia, glare, and poor vision in patients with congenital or trauma-induced iris damage. Commercial artificial iris lenses are static in nature to provide aesthetics without restoring the natural iris's dynamic response to light. A new photo-responsive artificial iris was therefore developed using a photochromic material with self-adaptive light transmission properties and encased in a transparent biocompatible polymer matrix. Methods The implantable artificial iris was designed and engineered using Photopia, a class of photo-responsive materials (termed naphthopyrans) embedded in polyethylene. Photopia was reshaped into annular disks that were spin-coated with polydimethylsiloxane (PDMS) to form our artificial iris lens of controlled thickness. Results Activated by UV and blue light in approximately 5 seconds with complete reversal in less than 1 minute, the artificial iris demonstrates graded attenuation of up to 40% of visible and 60% of UV light. There optical characteristics are suitable to reversibly regulate the incident light intensity. In vitro cell culture experiments showed up to 60% cell death within 10 days of exposure to Photopia, but no significant cell death observed when cultured with the artificial iris with protective encapsulation. Nuclear magnetic resonance spectroscopy confirmed these results as there was no apparent leakage of potentially toxic photochromic material from the ophthalmic device. Conclusions Our artificial iris lens mimics the functionality of the natural iris by attenuating light intensity entering the eye with its rapid reversible change in opacity and thus potentially providing an improved treatment option for patients with iris damage. PMID:27116547

  6. Attenuation of Vibrio fischeri quorum sensing using rationally designed polymers.

    Science.gov (United States)

    Piletska, Elena V; Stavroulakis, Georgios; Karim, Kal; Whitcombe, Michael J; Chianella, Iva; Sharma, Anant; Eboigbodin, Kevin E; Robinson, Gary K; Piletsky, Sergey A

    2010-04-12

    A first attempt to attenuate the quorum sensing (QS) of a marine heterotroph microorganism, Vibrio fischeri , using signal molecule-sequestering polymers (SSPs) is presented. A set of rationally designed polymers with affinity toward a signal molecule of V. fischeri , N-(beta-ketocaproyl)-l-homoserine lactone (3-oxo-C6-AHL) was produced. It is reported that computationally designed polymers could sequester a signal molecule of V. fischeri and prevent QS-controlled phenotypes (in this case, bioluminescence) from being up-regulated. It was proven that the attenuation of bioluminescence of V. fischeri was due to sequestration of the signal molecule by specific polymers and not due to the toxicity of polymer or nonspecific depletion of nutrients. The ability to disrupt the bacterial communication using easy to synthesize and chemically inert polymers could provide a new concept for the development of pharmaceuticals and susceptible device coatings such as catheters.

  7. The LCLS Gas Attenuator Revisited

    International Nuclear Information System (INIS)

    Ryutov, D

    2005-01-01

    In the report ''X-ray attenuation cell'' [1] a preliminary analysis of the gas attenuator for the Linac Coherent Light Source (LCLS) was presented. This analysis was carried out for extremely stringent set of specifications. In particular, a very large diameter for the unobstructed beam was set (1 cm) to accommodate the spontaneous radiation; the attenuator was supposed to cover the whole range of energies of the coherent radiation, from 800 eV to 8000 eV; the maximum attenuation was set at the level of 10 4 ; the use of solid attenuators was not allowed, as well as the use of rotating shutters. The need to reach a sufficient absorption at the high-energy end of the spectrum predetermined the choice of Xe as the working gas (in order to have a reasonable absorption at a not-too-high pressure). A sophisticated differential pumping system that included a Penning-type ion pump was suggested in order to minimize the gas leak into the undulator/accelerator part of the facility. A high cost of xenon meant also that an efficient (and expensive) gas-recovery system would have to be installed. The main parameter that determined the high cost and the complexity of the system was a large radius of the orifice. The present viewpoint allows for much smaller size of the orifice, r 0 = 1.5 mm. (1) The use of solid attenuators is also allowed (R.M. Bionta, private communication). It is, therefore, worthwhile to reconsider various parameters of the gas attenuator for these much less stringent conditions. This brief study should be considered as a physics input for the engineering design. As a working gas we consider now the argon, which, on the one hand, provides a reasonable absorption lengths and, on the other hand, is inexpensive enough to be exhausted into the atmosphere (no recovery). The absorption properties of argon are illustrated by Fig.1 where the attenuation factor A is shown for various beam energies, based on Ref. [2]. The other relevant parameters for argon are

  8. Josephson tunnel junction microwave attenuator

    DEFF Research Database (Denmark)

    Koshelets, V. P.; Shitov, S. V.; Shchukin, A. V.

    1993-01-01

    A new element for superconducting electronic circuitry-a variable attenuator-has been proposed, designed, and successfully tested. The principle of operation is based on the change in the microwave impedance of a superconductor-insulator-superconductor (SIS) Josephson tunnel junction when dc biased...... at different points in the current-voltage characteristic. Both numerical calculations based on the Tien-Gordon theory and 70-GHz microwave experiments have confirmed the wide dynamic range (more than 15-dB attenuation for one stage) and the low insertion loss in the ''open'' state. The performance of a fully...

  9. Gain attenuation of gated framing camera

    International Nuclear Information System (INIS)

    Xiao Shali; Liu Shenye; Cao Zhurong; Li Hang; Zhang Haiying; Yuan Zheng; Wang Liwei

    2009-01-01

    The theoretic model of framing camera's gain attenuation is analyzed. The exponential attenuation curve of the gain along the pulse propagation time is simulated. An experiment to measure the coefficient of gain attenuation based on the gain attenuation theory is designed. Experiment result shows that the gain follows an exponential attenuation rule with a quotient of 0.0249 nm -1 , the attenuation coefficient of the pulse is 0.00356 mm -1 . The loss of the pulse propagation along the MCP stripline is the leading reason of gain attenuation. But in the figure of a single stripline, the gain dose not follow the rule of exponential attenuation completely, instead, there is a gain increase at the stripline bottom. That is caused by the reflection of the pulse. The reflectance is about 24.2%. Combining the experiment and theory, which design of the stripline MCP can improved the gain attenuation. (authors)

  10. Transient attenuation in optical fibers

    International Nuclear Information System (INIS)

    Hopkins, A.A.; Kelly, R.E.; Looney, L.D.; Lyons, P.B.

    1984-01-01

    Low and high energy pulsed electron beams were used to generate radiation-induced transient attenuation in high-OH, Suprasil core, PCS fibers, demonstrating the energy dependence of the radiation damage and recovery mechanisms. A radiation resistant low-OH fiber was studied and its performance contrasted to that of high-OH materials. Several fibers with differing core compositions were also studied

  11. A Generalized Correction for Attenuation.

    Science.gov (United States)

    Petersen, Anne C.; Bock, R. Darrell

    Use of the usual bivariate correction for attenuation with more than two variables presents two statistical problems. This pairwise method may produce a covariance matrix which is not at least positive semi-definite, and the bivariate procedure does not consider the possible influences of correlated errors among the variables. The method described…

  12. Compact plasmonic variable optical attenuator

    DEFF Research Database (Denmark)

    Leosson, Kristjan; Rosenzveig, Tiberiu; Hermannsson, Pétur Gordon

    2008-01-01

    We demonstrate plasmonic nanowire-based thermo-optic variable optical attenuators operating in the 1525-1625 nm wavelength range. The devices have a footprint as low as 1 mm, extinction ratio exceeding 40 dB, driving voltage below 3 V, and full modulation bandwidth of 1 kHz. The polarization...

  13. Attenuation of Vrancea events revisited

    International Nuclear Information System (INIS)

    Radulian, M.; Popa, M.; Grecu, B.; Panza, G.F.

    2003-11-01

    New aspects of the frequency-dependent attenuation of the seismic waves traveling from Vrancea subcrustal sources toward NW (Transylvanian Basin) and SE (Romanian Plain) are evidenced by the recent experimental data made available by the CALIXTO'99 tomography experiment. The observations validate the previous theoretical computations performed for the assessment, by means of a deterministic approach, of the seismic hazard in Romania. They reveal an essential aspect of the seismic ground motion attenuation, that has important implications on the probabilistic assessment of seismic hazard from Vrancea intermediate-depth earthquakes. The attenuation toward NW is shown to be a much stronger frequency-dependent effect than the attenuation toward SE and the seismic hazard computed by the deterministic approach fits satisfactorily well the observed ground motion distribution in the low-frequency band (< 1 Hz). The apparent contradiction with the historically-based intensity maps arises mainly from a systematic difference in the vulnerability (buildings eigenperiod) of the buildings in the intra- and extra-Carpathians regions. (author)

  14. Toxic substances alert program

    Science.gov (United States)

    Junod, T. L.

    1978-01-01

    A toxicity profile is provided, of 187 toxic substances procured by NASA Lewis Research Center during a 3 1/2 year period, including 27 known or suspected carcinogens. The goal of the program is to assure that the center's health and safety personnel are aware of the procurement and use of toxic substances and to alert and inform the users of these materials as to the toxic characteristics and the control measures needed to ensure their safe use. The program also provides a continuing record of the toxic substances procured, who procured them, what other toxic substances the user has obtained in the past, and where similar materials have been used elsewhere at the center.

  15. SEISMIC ATTENUATION FOR RESERVOIR CHARACTERIZATION

    Energy Technology Data Exchange (ETDEWEB)

    Joel Walls; M.T. Taner; Gary Mavko; Jack Dvorkin

    2002-01-01

    In Section 1 of this first report we will describe the work we are doing to collect and analyze rock physics data for the purpose of modeling seismic attenuation from other measurable quantities such as porosity, water saturation, clay content and net stress. This work and other empirical methods to be presented later, will form the basis for ''Q pseudo-well modeling'' that is a key part of this project. In Section 2 of this report, we will show the fundamentals of a new method to extract Q, dispersion, and attenuation from field seismic data. The method is called Gabor-Morlet time-frequency decomposition. This technique has a number of advantages including greater stability and better time resolution than spectral ratio methods.

  16. Macroseismic intensity attenuation in Iran

    Science.gov (United States)

    Yaghmaei-Sabegh, Saman

    2018-01-01

    Macroseismic intensity data plays an important role in the process of seismic hazard analysis as well in developing of reliable earthquake loss models. This paper presents a physical-based model to predict macroseismic intensity attenuation based on 560 intensity data obtained in Iran in the time period 1975-2013. The geometric spreading and energy absorption of seismic waves have been considered in the proposed model. The proposed easy to implement relation describes the intensity simply as a function of moment magnitude, source to site distance and focal depth. The prediction capability of the proposed model is assessed by means of residuals analysis. Prediction results have been compared with those of other intensity prediction models for Italy, Turkey, Iran and central Asia. The results indicate the higher attenuation rate for the study area in distances less than 70km.

  17. ENHANCEMENTS TO NATURAL ATTENUATION: SELECTED CASE STUDIES

    Energy Technology Data Exchange (ETDEWEB)

    Vangelas, K; W. H. Albright, W; E. S. Becvar, E; C. H. Benson, C; T. O. Early, T; E. Hood, E; P. M. Jardine, P; M. Lorah, M; E. Majche, E; D. Major, D; W. J. Waugh, W; G. Wein, G; O. R. West, O

    2007-05-15

    In 2003 the US Department of Energy (DOE) embarked on a project to explore an innovative approach to remediation of subsurface contaminant plumes that focused on introducing mechanisms for augmenting natural attenuation to achieve site closure. Termed enhanced attenuation (EA), this approach has drawn its inspiration from the concept of monitored natural attenuation (MNA).

  18. R-flurbiprofen attenuates experimental autoimmune encephalomyelitis in mice.

    Science.gov (United States)

    Schmitz, Katja; de Bruin, Natasja; Bishay, Philipp; Männich, Julia; Häussler, Annett; Altmann, Christine; Ferreirós, Nerea; Lötsch, Jörn; Ultsch, Alfred; Parnham, Michael J; Geisslinger, Gerd; Tegeder, Irmgard

    2014-11-01

    R-flurbiprofen is the non-cyclooxygenase inhibiting R-enantiomer of the non-steroidal anti-inflammatory drug flurbiprofen, which was assessed as a remedy for Alzheimer's disease. Because of its anti-inflammatory, endocannabinoid-modulating and antioxidative properties, combined with low toxicity, the present study assessed R-flurbiprofen in experimental autoimmune encephalomyelitis (EAE) models of multiple sclerosis in mice. Oral R-flurbiprofen prevented and attenuated primary progressive EAE in C57BL6/J mice and relapsing-remitting EAE in SJL mice, even if the treatment was initiated on or after the first flare of the disease. R-flurbiprofen reduced immune cell infiltration and microglia activation and inflammation in the spinal cord, brain and optic nerve and attenuated myelin destruction and EAE-evoked hyperalgesia. R-flurbiprofen treatment increased CD4(+)CD25(+)FoxP3(+) regulatory T cells, CTLA4(+) inhibitory T cells and interleukin-10, whereas the EAE-evoked upregulation of pro-inflammatory genes in the spinal cord was strongly reduced. The effects were associated with an increase of plasma and cortical endocannabinoids but decreased spinal prostaglandins, the latter likely due to R to S inversion. The promising results suggest potential efficacy of R-flurbiprofen in human MS, and its low toxicity may justify a clinical trial. © 2014 The Authors. Published under the terms of the CC BY 4.0 license.

  19. Effects of attenuation map accuracy on attenuation-corrected micro-SPECT images

    NARCIS (Netherlands)

    Wu, C.; Gratama van Andel, H.A.; Laverman, P.; Boerman, O.C.; Beekman, F.J.

    2013-01-01

    Background In single-photon emission computed tomography (SPECT), attenuation of photon flux in tissue affects quantitative accuracy of reconstructed images. Attenuation maps derived from X-ray computed tomography (CT) can be employed for attenuation correction. The attenuation coefficients as well

  20. Females and Toxic Leadership

    Science.gov (United States)

    2012-12-14

    labeled as toxic, can he or she be rehabilitated?; Are there leadership styles that can be promoted to combat toxic leadership?; and Are the senior...examines leadership styles that are favorable for female leaders, and offers Transformational/Adaptive leadership as a style promising rehabilitative tools

  1. Mechanisms of Phosphine Toxicity

    Directory of Open Access Journals (Sweden)

    Nisa S. Nath

    2011-01-01

    Full Text Available Fumigation with phosphine gas is by far the most widely used treatment for the protection of stored grain against insect pests. The development of high-level resistance in insects now threatens its continued use. As there is no suitable chemical to replace phosphine, it is essential to understand the mechanisms of phosphine toxicity to increase the effectiveness of resistance management. Because phosphine is such a simple molecule (PH3, the chemistry of phosphorus is central to its toxicity. The elements above and below phosphorus in the periodic table are nitrogen (N and arsenic (As, which also produce toxic hydrides, namely, NH3 and AsH3. The three hydrides cause related symptoms and similar changes to cellular and organismal physiology, including disruption of the sympathetic nervous system, suppressed energy metabolism and toxic changes to the redox state of the cell. We propose that these three effects are interdependent contributors to phosphine toxicity.

  2. Pediatric Toxic Shock Syndrome

    Directory of Open Access Journals (Sweden)

    Jennifer Yee

    2017-09-01

    Full Text Available Audience: This scenario was developed to educate emergency medicine residents on the diagnosis and management of a pediatric patient with toxic shock syndrome. The case is also appropriate for teaching of medical students and advanced practice providers, as well as a review of the principles of crisis resource management, teamwork, and communication. Introduction: Toxic shock syndrome is a low-frequency, high-acuity scenario requiring timely identification and aggressive management. If patients suffering from this condition are managed incorrectly, they may progress into multi-organ dysfunction and potentially death. Toxic shock syndrome has been associated with Streptococcus and Staphylococcus aureus (Staph. Approximately half of Staph cases are associated with menstruation, which was first described in the 1970s-1980s and was associated with the use of absorbent tampons.1 Group A Streptococcus may cause complications such as necrotizing fasciitis and gangrenous myositis.2 Pediatric patients may present critically ill from toxic shock syndrome. Providers need to perform a thorough history and physical exam to discern the source of infection. Management requires aggressive care with antibiotics and IV fluids. Objectives: By the end of this simulation session, the learner will be able to: 1 Recognize toxic shock syndrome. 2 Review the importance of a thorough physical exam. 3 Discuss management of toxic shock syndrome, including supportive care and the difference in antibiotic choices for streptococcal and staphylococcal toxic shock syndrome. 4 Appropriately disposition a patient suffering from toxic shock syndrome. 5 Communicate effectively with team members and nursing staff during a resuscitation of a critically ill patient. Method: This session was conducted using high-fidelity simulation, followed by a debriefing session and lecture on toxic shock syndrome.

  3. Electronic Cigarette Toxicity.

    Science.gov (United States)

    Payne, J Drew; Michaels, David; Orellana-Barrios, Menfil; Nugent, Kenneth

    2017-04-01

    Electronic cigarettes (e-cigarettes) are often advertised as a healthier product when compared with traditional cigarettes. Currently, there are limited data to support this and only a threat of federal regulation from the US Food and Drug Administration. Calls to poison control centers about e-cigarette toxicity, especially in children, and case reports of toxic exposures have increased over the past 3 years. This research letter reports the frequency of hazardous exposures to e-cigarettes and characterizes the reported adverse health effects associated with e-cigarette toxicity.

  4. Toxicity Estimation Software Tool (TEST)

    Science.gov (United States)

    The Toxicity Estimation Software Tool (TEST) was developed to allow users to easily estimate the toxicity of chemicals using Quantitative Structure Activity Relationships (QSARs) methodologies. QSARs are mathematical models used to predict measures of toxicity from the physical c...

  5. Chlorine signal attenuation in concrete.

    Science.gov (United States)

    Naqvi, A A; Maslehuddin, M; Ur-Rehman, Khateeb; Al-Amoudi, O S B

    2015-11-01

    The intensity of prompt gamma-ray was measured at various depths from chlorine-contaminated silica fume (SF) concrete slab concrete specimens using portable neutron generator-based prompt gamma-ray setup. The intensity of 6.11MeV chloride gamma-rays was measured from the chloride contaminated slab at distance of 15.25, 20.25, 25.25, 30.25 and 35.25cm from neutron target in a SF cement concrete slab specimens. Due to attenuation of thermal neutron flux and emitted gamma-ray intensity in SF cement concrete at various depths, the measured intensity of chlorine gamma-rays decreases non-linearly with increasing depth in concrete. A good agreement was noted between the experimental results and the results of Monte Carlo simulation. This study has provided useful experimental data for evaluating the chloride contamination in the SF concrete utilizing gamma-ray attenuation method. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. SEISMIC ATTENUATION FOR RESERVOIR CHARACTERIZATION

    Energy Technology Data Exchange (ETDEWEB)

    Joel Walls; M.T. Taner; Naum Derzhi; Gary Mavko; Jack Dvorkin

    2003-12-01

    We have developed and tested technology for a new type of direct hydrocarbon detection. The method uses inelastic rock properties to greatly enhance the sensitivity of surface seismic methods to the presence of oil and gas saturation. These methods include use of energy absorption, dispersion, and attenuation (Q) along with traditional seismic attributes like velocity, impedance, and AVO. Our approach is to combine three elements: (1) a synthesis of the latest rock physics understanding of how rock inelasticity is related to rock type, pore fluid types, and pore microstructure, (2) synthetic seismic modeling that will help identify the relative contributions of scattering and intrinsic inelasticity to apparent Q attributes, and (3) robust algorithms that extract relative wave attenuation attributes from seismic data. This project provides: (1) Additional petrophysical insight from acquired data; (2) Increased understanding of rock and fluid properties; (3) New techniques to measure reservoir properties that are not currently available; and (4) Provide tools to more accurately describe the reservoir and predict oil location and volumes. These methodologies will improve the industry's ability to predict and quantify oil and gas saturation distribution, and to apply this information through geologic models to enhance reservoir simulation. We have applied for two separate patents relating to work that was completed as part of this project.

  7. Toxicity Reference Database

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Toxicity Reference Database (ToxRefDB) contains approximately 30 years and $2 billion worth of animal studies. ToxRefDB allows scientists and the interested...

  8. Toxics Release Inventory (TRI)

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Toxics Release Inventory (TRI) is a dataset compiled by the U.S. Environmental Protection Agency (EPA). It contains information on the release and waste...

  9. Calculation Of Pneumatic Attenuation In Pressure Sensors

    Science.gov (United States)

    Whitmore, Stephen A.

    1991-01-01

    Errors caused by attenuation of air-pressure waves in narrow tubes calculated by method based on fundamental equations of flow. Changes in ambient pressure transmitted along narrow tube to sensor. Attenuation of high-frequency components of pressure wave calculated from wave equation derived from Navier-Stokes equations of viscous flow in tube. Developed to understand and compensate for frictional attenuation in narrow tubes used to connect aircraft pressure sensors with pressure taps on affected surfaces.

  10. Estimating Rain Attenuation In Satellite Communication Links

    Science.gov (United States)

    Manning, R. M.

    1991-01-01

    Attenuation computed with help of statistical model and meteorological data. NASA Lewis Research Center Satellite Link Attenuation Model (SLAM) program QuickBASIC computer program evaluating static and dynamic statistical assessment of impact of rain attenuation on communication link established between Earth terminal and geosynchronous satellite. Application in specification, design, and assessment of satellite communication links for any terminal location in continental United States. Written in Microsoft QuickBASIC.

  11. Haloacetonitriles: metabolism and toxicity.

    Science.gov (United States)

    Lipscomb, John C; El-Demerdash, Ebtehal; Ahmed, Ahmed E

    2009-01-01

    The haloacetonitriles (HANs) exist in drinking water exclusively as byproducts of disinfection. HANs are found in drinking water more often, and in higher concentrations, when surface water is treated by chloramination. Human exposure occurs through consumption of finished drinking water; oral and dermal contact also occurs, and results from showering, swimming and other activities. HANs are reactive and are toxic to gastrointestinal tissues following oral administration. Such toxicity is characterized by GSH depletion, increased lipid peroxidation, and covalent binding of HAN-associated radioactivity to gut tissues. The presence of GSH in cells is an important protective mechanism against HAN toxicity; depletion of cellular GSH results in increased toxicity. Some studies have demonstrated an apparently synergistic effect between ROS and HAN administration, that may help explain effects observed in GI tissues. ROS are produced in gut tissues, and in vitro evidence indicates that ROS may contribute to the degradation and formation of reactive intermediates from HANs. The rationale for ROS involvement may involve HAN-induced depletion of GSH and the role of GSH in scavenging ROS. In addition to effects on GI tissues, studies show that HAN-derived radiolabel is found covalently bound to proteins and DNA in several organs and tissues. The addition of antioxidants to biologic systems protects against HAN-induced DNA damage. The protection offered by antioxidants supports the role of oxidative stress and the potential for a threshold in han-induced toxicity. However, additional data are needed to substantiate evidence for such a threshold. HANs are readily absorbed from the GI tract and are extensively metabolized. Elimination occurs primarily in urine, as unconjugated one-carbon metabolites. Evidence supports the involvement of mixed function oxidases, the cytochrome P450 enzyme family and GST, in HAN metabolism. Metabolism represents either a detoxification or

  12. Attenuation in Melting Layer of Precipitation

    NARCIS (Netherlands)

    Klaassen, W.

    1988-01-01

    A model of the melting layer is employed on radar measurements to simulate the attenuation of radio waves at 12, 20 and 30GHz. The attenuation in the melting layer is simulated to be slightly larger than that of rain with the same path length and precipitation intensity. The result appears to depend

  13. Precision Model for Microwave Rotary Vane Attenuator

    DEFF Research Database (Denmark)

    Guldbrandsen, Tom

    1979-01-01

    A model for a rotary vane attenuator is developed to describe the attenuator reflection and transmission coefficients in detail. All the parameters of the model can be measured in situ, i.e., without diassembling any part. The tranmission errors caused by internal reflections are calculated from ...

  14. Photostimulated attenuation of hypersound in superlattice

    International Nuclear Information System (INIS)

    Mensah, S.Y.; Allotey, F.K.; Adjepong, S.K.

    1992-10-01

    Photostimulated attenuation of hypersound in semiconductor superlattice has been investigated. It is shown that the attenuation coefficient depends on the phonon wave vector q in an oscillatory manner and that from this oscillation the band width Δ of superlattice can be found. (author). 14 refs, 1 fig

  15. The toxicity of plutonium

    International Nuclear Information System (INIS)

    Crouse, P.L.

    1994-01-01

    Shipments of plutonium occasionally pass around the Cape coastal waters on its way to Japan from Europe. This invariably leads to a great deal of speculation of the dangers involved and of the extreme toxicity of plutonium, with the media and environmental groups claiming that (a) plutonium is the most toxic substance known to man, and that (b) a few kilograms of plutonium ground finely and dispersed in the atmosphere could kill every human being on earth. Comparisons with other poisons are drawn, e.g. common inorganic chemicals and biological agents. The original scare around the extraordinary toxicity of Pu seems to have started in 1974 with the claims of Tamplin and Cochran's hot particle theory about plutonium lodging in the sensitive portions of the lungs in small concentrated aggregates where they are much more effective in producing cancers. This theory, however, is regarded as thoroughly discredited by the experts in the field of radiotoxicity. 8 refs

  16. Iron metabolism and toxicity

    International Nuclear Information System (INIS)

    Papanikolaou, G.; Pantopoulos, K.

    2005-01-01

    Iron is an essential nutrient with limited bioavailability. When present in excess, iron poses a threat to cells and tissues, and therefore iron homeostasis has to be tightly controlled. Iron's toxicity is largely based on its ability to catalyze the generation of radicals, which attack and damage cellular macromolecules and promote cell death and tissue injury. This is lucidly illustrated in diseases of iron overload, such as hereditary hemochromatosis or transfusional siderosis, where excessive iron accumulation results in tissue damage and organ failure. Pathological iron accumulation in the liver has also been linked to the development of hepatocellular cancer. Here we provide a background on the biology and toxicity of iron and the basic concepts of iron homeostasis at the cellular and systemic level. In addition, we provide an overview of the various disorders of iron overload, which are directly linked to iron's toxicity. Finally, we discuss the potential role of iron in malignant transformation and cancer

  17. Ultrasound fields in an attenuating medium

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt; Gandhi,, D; O'Brien,, W.D., Jr.

    1993-01-01

    of the rectangles and sums all contributions to arrive at the spatial impulse response for the aperture and field point. This approach makes it possible to model all transducer apertures, and the program can readily calculate the emitted, pulse-echo and continuous wave field. Attenuation is included by splitting...... it into a frequency dependent part and frequency independent part. The latter results in an attenuation factor that is multiplied onto the responses from the individual elements, and the frequency dependent part is handled by attenuating the basic one-dimensional pulse. The influence on ultrasound fields from......Ultrasound fields propagating in tissue will undergo changes in shape not only due to diffraction, but also due to the frequency dependent attenuation. Linear fields can be fairly well predicted for a non-attenuating medium like water by using the Tupholme-Stepanishen method for calculating...

  18. Beta attenuation transmission system (BATS)

    Energy Technology Data Exchange (ETDEWEB)

    Hagan, R.C.; Fullbright, H.J.

    1977-01-01

    The beta attenuation transmission system (BATS) is an automated radiation gauge designed for quantitative measurement of component thickness in explosive detonators. The BATS was designed and built by Group M-1, the Nondestructive Testing Group, of the Los Alamos Scientific Laboratory to measure the areal thickness, in mg/cm/sup 2/, of a cylinder of high explosive (HE) enclosed within a plastic holder. The problem is to determine the density of the HE. A /sup 90/Sr source is collimated by a 0.25 x 1.59-mm slit, and the transmitted beta-particle flux is detected by a plastic scintillator, coupled to a photomultiplier tube. The detonator is transported through the radiation beam by a leadscrew, ballnut, stepping-motor combination. Continuous analog position data are available, derived from the output from a linear-actuated potentiometer attached to the scanner. A linear electrometer amplifies the detected signal, which is then integrated for a preselected time, to obtain the desired statistical accuracy. A microprocessor (..mu..P) is used to control the scanner position and to make the data readings at the assigned positions. The data are stored, and, at the completion of the scan, are processed into the desired format. The final answer is displayed to the operator or output to a peripheral device for permanent record. The characteristics of the radiation source, the collimator, the signal detection and conditioning, and the final results are described in detail. The scanner and the microprocessor control system are briefly outlined.

  19. Transport and attenuation of radiations

    CERN Document Server

    Nimal, J C

    2003-01-01

    This article treats of the calculation methods used for the dimensioning of the protections against radiations. The method consists in determining for a given point the flux of particles coming from a source at a given time. A strong attenuation (of about some few mu Sv.h sup - sup 1) is in general expected between the source and the areas accessible to the personnel or the public. The calculation has to take into account a huge number of radiation-matter interactions and to solve the integral-differential transport equation which links the particles flux to the source. Several methods exist from the simplified physical model with numerical developments to the more or less precise resolution of the transport equation. These methods allows also the calculation of the uncertainties of equivalent dose rates, heat sources, structure damages using the data covariances (efficient cross-sections, modeling, etc..): 1 - transport equation; 2 - Monte-Carlo method; 3 - semi-numerical methods S sub N; 4 - methods based o...

  20. Plasmodium falciparum: attenuation by irradiation

    International Nuclear Information System (INIS)

    Waki, S.; Yonome, I.; Suzuki, M.

    1983-01-01

    The effect of irradiation on the in vitro growth of Plasmodium falciparum was investigated. The cultured malarial parasites at selected stages of development were exposed to gamma rays and the sensitivity of each stage was determined. The stages most sensitive to irradiation were the ring forms and the early trophozoites; late trophozoites were relatively insensitive. The greatest resistance was shown when parasites were irradiated at a time of transition from the late trophozoite and schizont stages to young ring forms. The characteristics of radiosensitive variation in the parasite cycle resembled that of mammalian cells. Growth curves of parasites exposed to doses of irradiation upto 150 gray had the same slope as nonirradiated controls but parasites which were exposed to 200 gray exhibited a growth curve which was less steep than that for parasites in other groups. Less than 10 organisms survived from the 10(6) parasites exposed to this high dose of irradiation; the possibility exists of obtaining radiation-attenuated P. falciparum

  1. Beta attenuation transmission system (BATS)

    International Nuclear Information System (INIS)

    Hagan, R.C.; Fullbright, H.J.

    1977-01-01

    The beta attenuation transmission system (BATS) is an automated radiation gauge designed for quantitative measurement of component thickness in explosive detonators. The BATS was designed and built by Group M-1, the Nondestructive Testing Group, of the Los Alamos Scientific Laboratory to measure the areal thickness, in mg/cm 2 , of a cylinder of high explosive (HE) enclosed within a plastic holder. The problem is to determine the density of the HE. A 90 Sr source is collimated by a 0.25 x 1.59-mm slit, and the transmitted beta-particle flux is detected by a plastic scintillator, coupled to a photomultiplier tube. The detonator is transported through the radiation beam by a leadscrew, ballnut, stepping-motor combination. Continuous analog position data are available, derived from the output from a linear-actuated potentiometer attached to the scanner. A linear electrometer amplifies the detected signal, which is then integrated for a preselected time, to obtain the desired statistical accuracy. A microprocessor (μP) is used to control the scanner position and to make the data readings at the assigned positions. The data are stored, and, at the completion of the scan, are processed into the desired format. The final answer is displayed to the operator or output to a peripheral device for permanent record. The characteristics of the radiation source, the collimator, the signal detection and conditioning, and the final results are described in detail. The scanner and the microprocessor control system are briefly outlined

  2. Attenuation characteristics of gypsum wallboard

    International Nuclear Information System (INIS)

    Christensen, Ralph C.; Sayeg, Joseph

    1978-01-01

    Increased cost of lead is promoting enhanced usage of common building materials for shielding in diagnostic medical and dental facilities where only a few half value layers (HVLs) are needed. We have measured attenuation of x-rays in gypsum wallboard as a function of kVp, filtration, and wallboard thickness. Our findings, obtained using a Victoreen 555 with an 0.1 DAS probe in poor geometry, are in agreement with the sparse data in the literature (Gross and McCullough (1977), Radiology 122: 825. Moos et al. (1961), Oral Surgery, Oral Medicine, and Oral Pathology 14: 569) but extend to thicker wall configurations and different kVp and filtration parameters. We conclude that gypsum wallboard as sole shielding material should be used with great caution. These findings are of value in maximizing the benefit/cost ratio for diagnostic shielding, and strengthen the conviction that, where used for shielding purposes, common building materials must be installed carefully and HVL-depth dependence considered thoroughly. (author)

  3. External radiation toxicity

    International Nuclear Information System (INIS)

    Fritz, T.E.

    1979-01-01

    The section contains summaries of research on neutron and gamma-ray toxicity in rodents, late effects of low-dose rate, whole-body, protracted exposure to 60 Co gamma rays on young adult beagles, and the effects of protracted, low-dose rate exposure to 60 Co gamma rays on preclinical leukemic phase-related changes in the granulopoietic system of beagles

  4. Local anaesthetic toxicity

    African Journals Online (AJOL)

    Local anaesthetic toxicity has been known since the introduction of local anaesthetic drugs into anaesthetic practice more than a hundred ... was the first to think of cocaine as a narcotic. ..... anaesthetics act as Na+ channel-blocking agents, they slow down .... all neurons, leading to global CNS depression, slowing and.

  5. Toxicity of lunar dust

    NARCIS (Netherlands)

    Linnarsson, D.; Carpenter, J.; Fubini, B.; Gerde, P.; Loftus, D.; Prisk, K.; Staufer, U.; Tranfield, E.; van Westrenen, W.

    2012-01-01

    The formation, composition and physical properties of lunar dust are incompletely characterised with regard to human health. While the physical and chemical determinants of dust toxicity for materials such as asbestos, quartz, volcanic ashes and urban particulate matter have been the focus of

  6. Uranium: biokinetics and toxicity

    International Nuclear Information System (INIS)

    Menetrier, F.; Renaud-Salis, V.; Flury-Herard, A.

    2000-01-01

    This report was achieved as a part of a collaboration with the Fuel Cycle Direction. Its aim was to give the state of the art about: the behaviour of uranium in the human organism (biokinetics) after ingestion, its toxicity (mainly renal) and the current regulation about its incorporation. Both in the upstream and in the downstream of the fuel cycle, uranium remains, quantitatively, the first element in the cycle which is, at the present time, temporarily disposed or recycled. Such a considerable quantity of uranium sets the problem of its risk on the health. In the long term, the biosphere may be affected and consequently the public may ingest water or food contaminated with uranium. In this way, radiological and chemical toxicity risk may be activated. This report emphasizes: the necessity of confirming some experimental and epidemiological biokinetic data used or not in the ICRP models. Unsolved questions remain about the gastrointestinal absorption according to chemical form (valency state, mixtures...), mass and individual variations (age, disease) further a chronic ingestion of uranium. It is well established that uranium is mainly deposited in the skeleton and the kidney. But the skeleton kinetics following a chronic ingestion and especially in some diseases has to be more elucidated; the necessity of taking into account uranium at first as a chemical toxic, essentially in the kidney and determining the threshold of functional lesion. In this way, it is important to look for some specific markers; the problem of not considering chemical toxicity of uranium in the texts regulating its incorporation

  7. How toxic is ibogaine?

    NARCIS (Netherlands)

    Litjens, Ruud P. W.; Brunt, Tibor M.

    2016-01-01

    Ibogaine is a psychoactive indole alkaloid found in the African rainforest shrub Tabernanthe Iboga. It is unlicensed but used in the treatment of drug and alcohol addiction. However, reports of ibogaine's toxicity are cause for concern. To review ibogaine's pharmacokinetics and pharmacodynamics,

  8. Monosodium Glutamate Toxicity

    African Journals Online (AJOL)

    Dr Olaleye

    The brain is reportedly sensitive to monosodium glutamate (MSG) toxicity via oxidative stress. Sida acuta leaf ethanolic .... wherein the right hemisphere, was preserved for histology and fixed in 10% ... Biochemical Assays: The left hemisphere of the brain samples was ...... development in male and female rats. Exp Physiol.

  9. Nanomaterials and Retinal Toxicity

    Science.gov (United States)

    The neuroretina should be considered as a potential site of nanomaterial toxicity. Engineered nanomaterials may reach the retina through three potential routes of exposure including; intra­ vitreal injection of therapeutics; blood-borne delivery in the retinal vasculature an...

  10. Toxic Hazards in Aviation.

    Science.gov (United States)

    1981-04-01

    Pasteur, Lillm,FRANCE. (2) CONISH H.H., EARTH M.L.& IANNi F.L, "Comparative Toxicology of Platics during Thar-modecoqiorition Intsw-re8posium on...Pyrolysnis and Combustion of Materials" Firm and Materials (1976).1, 29-35 (8) ALAAIE Y."Toxicity of Platic dacomposition ProductsŖd Annu~al Progress

  11. Interaction between Ammonium Toxicity and Green Tide Development Over Seagrass Meadows

    DEFF Research Database (Denmark)

    Marin, Francisco Moreno; Vergara, Juan J.; Pérez-Llorens, J. Lucas

    2016-01-01

    Eutrophication affects seagrasses negatively by increasing light attenuation through stimulation of biomass of fast-growing, bloom-forming algae and because high concentrations of ammonium in the water can be toxic to higher plants. We hypothesized nevertheless, that moderate amounts of nitrophil...

  12. Inhibitory effect of live-attenuated Listeria monocytogenes-based vaccines expressing MIA gene on malignant melanoma.

    Science.gov (United States)

    Qian, Yue; Zhang, Na; Jiang, Ping; Chen, Siyuan; Chu, Shujuan; Hamze, Firas; Wu, Yan; Luo, Qin; Feng, Aiping

    2012-08-01

    Listeria monocytogenes (LM), a Gram-positive facultative intracellular bacterium, can be used as an effective exogenous antigen expression vector in tumor-target therapy. But for successful clinical application, it is necessary to construct attenuated LM stain that is safe yet retains the potency of LM based on the full virulent pathogen. In this study, attenuated LM and recombinants of LM expressing melanoma inhibitory activity (MIA) were constructed successfully. The median lethal dose (LD(50)) and invasion efficiency of attenuated LM strains were detected. The recombinants were utilized for immunotherapy of animal model of B16F10 melanoma. The level of MIA mRNA expression in tumor tissue was detected by using real-time polymerase chain reaction (PCR) with specific sequence, meanwhile the anti-tumor immune response was assayed by flow cytometric analysis and enzyme-linked immunosorbent spot (ELISPOT) assay. The results showed the toxicity and invasiveness of attenuated LM were decreased as compared with LM, and attenuated LM expressing MIA, especially the double-genes attenuated LM recombinant, could significantly induce anti-tumor immune response and inhibit tumor growth. This study implicates attenuated LM may be a safer and more effective vector for immunotherapy of melanoma.

  13. Estimation of toxicity using the Toxicity Estimation Software Tool (TEST)

    Science.gov (United States)

    Tens of thousands of chemicals are currently in commerce, and hundreds more are introduced every year. Since experimental measurements of toxicity are extremely time consuming and expensive, it is imperative that alternative methods to estimate toxicity are developed.

  14. Light attenuation in estuarine mangrove lakes

    Science.gov (United States)

    Frankovich, Thomas A.; Rudnick, David T.; Fourqurean, James W.

    2017-01-01

    Submerged aquatic vegetation (SAV) cover has declined in brackish lakes in the southern Everglades characterized by low water transparencies, emphasizing the need to evaluate the suitability of the aquatic medium for SAV growth and to identify the light attenuating components that contribute most to light attenuation. Underwater attenuation of downwards irradiance of photosynthetically active radiation (PAR) was determined over a three year period at 42 sites in shallow (freshwater flow into these areas may dilute CDOM concentrations and improve the salinity and light climate for SAV communities.

  15. Differential toxicity and influence of salinity on acute toxicity of ...

    African Journals Online (AJOL)

    Differential toxicity and influence of salinity on acute toxicity of copper sulphate and lead nitrate against Oreochromis niloticus. KA Bawa-Allah, F Osuala, J Effiong. Abstract. This study investigated the salinity-tolerance of Oreochromis niloticus and the influence of salinity changes on the acute toxicities of copper sulphate ...

  16. Enhanced replication of attenuated HSV-1 in irradiated human glioma xenografts

    International Nuclear Information System (INIS)

    Advani, Sunil J.; Kataoka, Yasushi; Sibley, Greg S.; Song, Paul Y.; Hallahan, Dennis E.; Roizman, Bernard; Weichselbaum, Ralph R.

    1997-01-01

    Purpose: Previously we had shown that combining ionizing radiation (IR) with attenuated replication competent HSV-1 (R3616) significantly increased glioma xenograft eradication compared to IR or virus alone. One hypothesis is that IR induces cell factors that contribute to augment viral replication thereby increasing the efficacy of attenuated HSV-1. The purpose of this study was to examine if IR altered viral replication of attenuated HSV-1 in glioma xenografts Material and Methods: Human U-87MG glioma cells were grown in the hindlimb of athymic mice and grown to >200 mm 3 . Tumors were infected with 2x10 7 plaque forming units (pfu) of R3616 ( γ1 34.5 - ) or R7020 (multimutated, γ1 34.5 + ) on day 0 and irradiated with 20 Gy on day 1 and 25 Gy on day 2. Tumors were harvested 3, 5, 7, and 14 days after viral injection. Tumors were homogenized and sonnicated. Serial dilutions of tumor extract were overlaid on Vero cells to determine the number of pfu. In addition, in-situ hybridization to HSV-1 DNA was performed on tumors harvested at day 7. Results: In-situ hybridization revealed larger numbers of glial cells infected with HSV along with a greater distribution in the irradiated tumors compared to non-irradiated tumors. We next quantified viral particles in infected tumors +/- IR: Conclusion: Herein we demonstrate radiation enhanced viral replication as one of the interactive effects of combining IR and attenuated HSV in treating glioma xenografts and a potential therapeutic motif in the treatment of gliomas. To reduce normal tissue toxicity of HSV in glioma therapy, viruses must be attenuated. However, attenuating the virus compromises its replication and thus its potential efficacy. Our results indicate that IR augments the amount of virus recovered from human glioma xenografts for up to 3 days post IR. The results do not appear to be related to a specific mutation in the herpes genome but rather to herpes viruses in general. Yields of R7020 were greater than R

  17. Biological control of toxic cyanobacteri

    CSIR Research Space (South Africa)

    Ndlela, Luyanda L

    2017-05-01

    Full Text Available . Ecotoxicity studies: is toxicity reduced? (Testing on daphnids, fish and human cell lines) Resulting impacts on cyanotoxins (Toxin conformation changes, ELISA detection) Competition assays against toxic cyanobacteria (Can Bacillus etc. outcompete...

  18. Allegheny County Toxics Release Inventory

    Data.gov (United States)

    Allegheny County / City of Pittsburgh / Western PA Regional Data Center — The Toxics Release Inventory (TRI) data provides information about toxic substances released into the environment or managed through recycling, energy recovery, and...

  19. Toxic waste liquor disposal

    International Nuclear Information System (INIS)

    Burton, W.R.

    1985-01-01

    Toxic waste liquors, especially radio active liquors, are disposed in a sub-zone by feeding down a bore hole a first liquid, then a buffer liquid (e.g. water), then the toxic liquors. Pressure variations are applied to the sub-zone to mix the first liquid and liquors to form gels or solids which inhibit further mixing and form a barrier between the sub-zone and the natural waters in the environment of the sub-zone. In another example the location of the sub-zone is selected so that the environement reacts with the liquors to produce a barrier around the zone. Blind bore holes are used to monitor the sub-zone profile. Materials may be added to the liquor to enhance barrier formation. (author)

  20. Seismic attenuation system for a nuclear reactor

    Energy Technology Data Exchange (ETDEWEB)

    Liszkai, Tamas; Cadell, Seth

    2018-01-30

    A system for attenuating seismic forces includes a reactor pressure vessel containing nuclear fuel and a containment vessel that houses the reactor pressure vessel. Both the reactor pressure vessel and the containment vessel include a bottom head. Additionally, the system includes a base support to contact a support surface on which the containment vessel is positioned in a substantially vertical orientation. An attenuation device is located between the bottom head of the reactor pressure vessel and the bottom head of the containment vessel. Seismic forces that travel from the base support to the reactor pressure vessel via the containment vessel are attenuated by the attenuation device in a direction that is substantially lateral to the vertical orientation of the containment vessel.

  1. Dexmedetomidine in premedication to attenuate the acute ...

    African Journals Online (AJOL)

    Background: The choice of anaesthetic agent for electroconvulsive therapy (ECT) depends on seizure duration, haemodynamic ... and infarction. To attenuate this acute ... scheduled for ECT, physical status ASA I and II, age between 18 and.

  2. Attenuation measurements in solutions of some carbohydrates

    International Nuclear Information System (INIS)

    Gagandeep; Singh, K.; Lark, B.S.; Sahota, H.S.

    2000-01-01

    The linear attenuation coefficients in aqueous solutions of three carbohydrates, glucose (C 6 H 12 O 6 ), maltose monohydrate (C 12 H 22 O 11 ·H 2 O), and sucrose (C 12 H 22 O 11 ), were determined at 81, 356, 511, 662, 1,173, and 1,332 keV by the gamma-ray transmission method in a good geometry setup. From the precisely measured densities of these solutions, mass attenuation coefficients were then obtained that varied systematically with the corresponding changes in the concentrations (g/cm 3 ) of these solutions. The experimental results were used in terms of effective atomic numbers and electron densities. A comparison between experimental and theoretical values of attenuation coefficients has proven that the study has a potential application for the determination of attenuation coefficients of solid solutes from their solutions without obtaining them in pure crystalline form

  3. Attenuation Measurements in Solutions of Some Carbohydrates

    International Nuclear Information System (INIS)

    Gagandeep; Singh, Kulwant; Lark, B.S.; Sahota, H.S.

    2000-01-01

    The linear attenuation coefficients in aqueous solutions of three carbohydrates, glucose (C 6 H 12 O 6 ), maltose monohydrate (C 12 H 22 O 11 .H 2 O), and sucrose (C 12 H 22 O 11 ), were determined at 81, 356, 511, 662, 1173, and 1332 keV by the gamma-ray transmission method in a good geometry setup. From the precisely measured densities of these solutions, mass attenuation coefficients were then obtained that varied systematically with the corresponding changes in the concentrations (g/cm 3 ) of these solutions. The experimental results were used in terms of effective atomic numbers and electron densities. A comparison between experimental and theoretical values of attenuation coefficients has proven that the study has a potential application for the determination of attenuation coefficients of solid solutes from their solutions without obtaining them in pure crystalline form

  4. Radiation-attenuated vaccine for lungworm disease

    International Nuclear Information System (INIS)

    Singh, C.M.

    1977-01-01

    The work done at the Indian Veternary Research Institute, Izatnagar, on the development of a vaccine for lungworm diseases is reported. Research work done includes: (1) studies on the epidemiology and the incidence of the lungworm infections, (ii) studies on the radiation-attenuated lungworm Dictyocaulus filaria vaccine, (iii) studies on other parasites using ionizing radiation, (iv) incidence of lungworm infection in sheep in Jammu and Kashmir State, (v) suitable dose of gamma radiation for attenuation, (vi) laboratory studies with radiation-attenuated D. filaria vaccine, (vii) serology of D. filaria infection, (viii) field trials with the radiation-attenuated vaccine, (ix) immune response of previously exposed lambs to vaccination, (x) comparative susceptibility of sheep and goats to infection with D. filaria, (xi) quantitative studies of D. filaria in lambs and (xii) production and supply of lungworm vaccine. (A.K.)

  5. Portable, accurate toxicity testing

    International Nuclear Information System (INIS)

    Sabate, R.W.; Stiffey, A.V.; Dewailly, E.L.; Hinds, A.A.; Vieaux, G.J.

    1994-01-01

    Ever tightening environmental regulations, severe penalties for non-compliance, and expensive remediation costs have stimulated development of methods to detect and measure toxins. Most of these methods are bioassays that must be performed in the laboratory; none previously devised has been truly portable. The US Army, through the Small Business Innovative Research program, has developed a hand-held, field deployable unit for testing toxicity of battlefield water supplies. This patented system employs the measurable quenching, in the presence of toxins, of the natural bioluminescence produced by the marine dinoflagellate alga Pyrocystis lunula. The procedure's inventor used it for years to measure toxicity concentrations of chemical warfare agents actually, their simulants, primarily in the form of pesticides and herbicides plus assorted toxic reagents, waterbottom samples, drilling fluids, even blood. While the procedure is more precise, cheaper, and faster than most bioassays, until recently it was immobile. Now it is deployable in the field. The laboratory apparatus has been proven to be sensitive to toxins in concentrations as low as a few parts per billion, repeatable within a variation of 10% or less, and unlike some other bioassays effective in turbid or colored media. The laboratory apparatus and the hand-held tester have been calibrated with the EPA protocol that uses the shrimplike Mysidopsis bahia. The test organism tolerates transportation well, but must be rested a few hours at the test site for regeneration of its light-producing powers. Toxicity now can be measured confidently in soils, water columns, discharge points, and many other media in situ. Most significant to the oil industry is that drilling fluids can be monitored continuously on the rig

  6. Lead toxicity: current concerns.

    OpenAIRE

    Goyer, R A

    1993-01-01

    Over the 20-year period since the first issue of Environmental Health Perspectives was published, there has been considerable progress in the understanding of the potential toxicity of exposure to lead. Many of these advances have been reviewed in published symposia, conferences, and review papers in EHP. This brief review identifies major advances as well as a number of current concerns that present opportunities for prevention and intervention strategies. The major scientific advance has be...

  7. Toxic Substances Control Act

    Energy Technology Data Exchange (ETDEWEB)

    1992-05-15

    This Reference Book contains a current copy of the Toxic Substances Control Act and those regulations that implement the statute and appear to be most relevant to DOE activities. The document is provided to DOE and contractor staff for informational purposes only and should not be interpreted as legal guidance. Questions concerning this Reference Book may be directed to Mark Petts, EH-231 (202/586-2609).

  8. Kombucha--toxicity alert.

    Science.gov (United States)

    The Kombucha mushroom, also known as Manchurian mushroom, is a mail-order product touted to lower blood pressure and raise T-cell counts. No controlled trials have been conducted to test these claims. Aspergillus, a mold that may grow on the Kombucha mushroom, attacks the brain and may be fatal to persons with weakened immune systems. Reported toxicity reactions have included stomach problems and yeast infections. Taking Kombucha in combination with other drugs may affect the drugs potency.

  9. Toxicity of nitrogen pentoxide

    Energy Technology Data Exchange (ETDEWEB)

    Diggle, W M; Gage, J C

    1954-01-01

    Two ppM N/sub 2/O/sub 5/ for 4 h or 1 ppM, 4 h/day for 12 days produced acute pulmonary edema in rats. Ten daily 4-h exposures to 0.5 ppM produced no edema but respiratory distress. NO/sub 2/ produced no edema (some hemorrhage) at 80 mg/m/sup 3/. Nitric acid vapor (63 mg/m/sup 3/) had no obvious toxic effect.

  10. Post-Retrieval Extinction Attenuates Cocaine Memories

    OpenAIRE

    Sartor, Gregory C; Aston-Jones, Gary

    2013-01-01

    Recent studies have shown that post-retrieval extinction training attenuates fear and reward-related memories in both humans and rodents. This noninvasive, behavioral approach has the potential to be used in clinical settings to treat maladaptive memories that underlie several psychiatric disorders, including drug addiction. However, few studies to date have used a post-retrieval extinction approach to attenuate addiction-related memories. In the current study, we attempted to disrupt cocaine...

  11. Electron Effective-Attenuation-Length Database

    Science.gov (United States)

    SRD 82 NIST Electron Effective-Attenuation-Length Database (PC database, no charge)   This database provides values of electron effective attenuation lengths (EALs) in solid elements and compounds at selected electron energies between 50 eV and 2,000 eV. The database was designed mainly to provide EALs (to account for effects of elastic-eletron scattering) for applications in surface analysis by Auger-electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS).

  12. Investigation of photon attenuation coefficients for marble

    International Nuclear Information System (INIS)

    Basyigit, C; Akkurt, I; Kilincarslan, S; Akkurt, A

    2005-01-01

    The total linear attenuation coefficients μ (cm -1 ) have been obtained using the XCOM program at photon energies of 1 keV to 1 GeV for six different natural marbles produced in different places in Turkey. The individual contribution of photon interaction processes to the total linear attenuation coefficients for marble has been investigated. The calculated results were also compared with the measurements. The results obtained for marble were also compared with concrete. (note)

  13. Separations chemistry of toxic metals

    International Nuclear Information System (INIS)

    Smith, P.; Barr, M.; Barrans, R.

    1996-01-01

    Sequestering and removing toxic metal ions from their surroundings is an increasingly active area of research and is gaining importance in light of current environmental contamination problems both within the DOE complex and externally. One method of separating metal ions is to complex them to a molecule (a ligand or chelator) which exhibits specific binding affinity for a toxic metal, even in the presence of other more benign metals. This approach makes use of the sometimes subtle differences between toxic and non-toxic metals resulting from variations in size, charge and shape. For example, toxic metals such as chromium, arsenic, and technetium exist in the environment as oxyanions, negatively charged species with a characteristic tetrahedral shape. Other toxic metals such as actinides and heavy metals are positively charged spheres with specific affinities for particular donor atoms such as oxygen (for actinides) and nitrogen (for heavy metals). In most cases the toxic metals are found in the presence of much larger quantities of less toxic metals such as sodium, calcium and iron. The selectivity of the chelators is critical to the goal of removing the toxic metals from their less toxic counterparts. The approach was to build a ligand framework that complements the unique characteristics of the toxic metal (size, charge and shape) while minimizing interactions with non-toxic metals. The authors have designed ligands exhibiting specificity for the target metals; they have synthesized, characterized and tested these ligands; and they have shown that they exhibit the proposed selectivity and cooperative binding effects

  14. Mechanisms of geometrical seismic attenuation

    Directory of Open Access Journals (Sweden)

    Igor B. Morozov

    2011-07-01

    Full Text Available In several recent reports, we have explained the frequency dependence of the apparent seismic quality-factor (Q observed in many studies according to the effects of geometrical attenuation, which was defined as the zero-frequency limit of the temporal attenuation coefficient. In particular, geometrical attenuation was found to be positive for most waves traveling within the lithosphere. Here, we present three theoretical models that illustrate the origin of this geometrical attenuation, and we investigate the causes of its preferential positive values. In addition, we discuss the physical basis and limitations of both the conventional and new attenuation models. For waves in media with slowly varying properties, geometrical attenuation is caused by variations in the wavefront curvature, which can be both positive (for defocusing and negative (for focusing. In media with velocity/density contrasts, incoherent reflectivity leads to geometrical-attenuation coefficients which are proportional to the mean squared reflectivity and are always positive. For «coherent» reflectivity, the geometrical attenuation is approximately zero, and the attenuation process can be described according to the concept of «scattering Q». However, the true meaning of this parameter is in describing the mean reflectivity within the medium, and not that of the traditional resonator quality factor known in mechanics. The general conclusion from these models is that non-zero and often positive levels of geometrical attenuation are common in realistic, heterogeneous media, both observationally and theoretically. When transformed into the conventional Q-factor form, this positive geometrical attenuation leads to Q values that quickly increase with frequency. These predictions show that the positive frequency-dependent Q observed in many datasets might represent artifacts of the transformations of the attenuation coefficients into Q.

  1. Metal metabolism and toxicity

    International Nuclear Information System (INIS)

    Bhattacharyya, M.H.; Larsen, R.P.; Whelton, B.D.; Moretti, E.S.; Peterson, D.P.; Oldham, R.D.

    1985-01-01

    This research focuses on the role of pregnancy and lactation in susceptibility to the toxic effects of cadmium and lead. Responses under investigation include lead-induced changes in pathways for vitamin D and calcium metabolism and cadmium-induced alterations in kidney function and skeletal structure. The second area focuses on the gastrointestinal absorption of plutonium and other actinide elements. Studies currently being conducted in nonhuman primates to develop a procedure to determine GI absorption values of uranium and plutonium that does not require sacrifice of the animal. 6 refs

  2. Control of air toxics

    International Nuclear Information System (INIS)

    Livengood, C.D.

    1995-01-01

    For more than 10 years, Argonne National Laboratory has supported the US DOE's Flue Gas Cleanup Program objective by developing new or improved environmental controls for industries that use fossil fuels. Argonne's pollutant emissions research has ranged from experiments in the basic chemistry of pollution-control systems, through laboratory-scale process development and testing, to pilot-scale field tests of several technologies. The work on air toxics is currently divided into two components: Investigating measures to improve the removal of mercury in existing pollution-control systems applied to coal combustion; and, Developing sensors and control techniques for emissions found in the textile industry

  3. Fat Attenuation at CT in Anorexia Nervosa

    Science.gov (United States)

    Gill, Corey M.; Torriani, Martin; Murphy, Rachel; Harris, Tamara B.; Miller, Karen K.; Klibanski, Anne

    2016-01-01

    Purpose To investigate the composition, cross-sectional area (CSA), and hormonal correlates of different fat depots in women with anorexia nervosa (AN) and control subjects with normal weights to find out whether patients with AN have lower fat CSA but higher attenuation than did control subjects and whether these changes may be mediated by gonadal steroids, cortisol, and thyroid hormones. Materials and Methods This study was institutional review board approved and HIPAA compliant. Written informed consent was obtained. Forty premenopausal women with AN and 40 normal-weight women of comparable age (mean age ± standard deviation, 26 years ± 5) were studied. All individuals underwent computed tomography of the abdomen and thigh with a calibration phantom. Abdominal subcutaneous adipose tissue (SAT), visceral adipose tissue (VAT), thigh SAT, and thigh intermuscular adipose tissue CSA and attenuation were quantified. Serum estradiol, thyroid hormones, and urinary free cortisol levels were assessed. Variables were compared by using analysis of variance. Associations were examined by using linear regression analysis. Results Women with AN had higher fat attenuation than did control subjects (−100.1 to −46.7 HU vs −117.6 to −61.8 HU, P < .0001), despite lower fat CSA (2.0–62.8 cm2 vs 5.5–185.9 cm2, P < .0001). VAT attenuation but not CSA was inversely associated with lowest prior lifetime body mass index in AN (r = −0.71, P = .006). Serum estradiol levels were inversely associated with fat attenuation (r = −0.34 to −0.61, P = .03 to <.0001) and were positively associated with fat CSA of all compartments (r = 0.42–0.64, P = .007 to <.0001). Thyroxine levels and urinary free cortisol levels were positively associated with thigh SAT attenuation (r = 0.64 [P = .006] and r = 0.68 [P = .0004], respectively) and were inversely associated with abdominal SAT and VAT CSA (r = −0.44 to −0.58, P = .04 to .02). Conclusion Women with AN have differences in fat

  4. Attenuation of Brain Hyperbaric Oxygen Toxicity of Fasting is Not Related to Ketosis

    National Research Council Canada - National Science Library

    Chavko, M

    1999-01-01

    The objective of this study was to determine if protection from HBO2 seizures by acute, short fasting is related to the ketosis or to the mild hypoglycemia resulting from this treatment, or to both...

  5. Moringa oleifera extract (Lam) attenuates Aluminium phosphide-induced acute cardiac toxicity in rats.

    Science.gov (United States)

    Gouda, Ahmed S; El-Nabarawy, Nagla A; Ibrahim, Samah F

    2018-01-01

    Moringa oleifera extract (Lam) has many antioxidant and protective properties. Objective: to investigate the antioxidant activities of Lam in counteracting the high oxidative stress caused by acute sub-lethal aluminium phosphide (AlP) intoxication in rat heart. These activities will be detected by histopathological examination and some oxidative stress biomarkers. a single sub-lethal dose of Alp (2 mg/kg body weight) was administered orally, and Lam was given orally at a dose (100 mg/kg body weight) one hour after receiving AlP to rats. aluminium phosphide caused significant cardiac histopathological changes with a significant increase in malondialdehyde (MDA); lipid peroxidation marker; and a significant depletion of antioxidant enzymes (catalase and glutathione reductase). However, treatment with Lam protected efficiently the cardiac tissue of intoxicated rats by increasing antioxidants levels with slight decreasing in MDA production compared to untreated group. This study suggested that Moringa oleifera extract could possibly restore the altered cardiac histopathology and some antioxidant power in AlP intoxicated rats, and it could even be used as adjuvant therapy against AlP-induced cardiotoxicity.

  6. Elastic wave attenuation in rocks containing fluids

    International Nuclear Information System (INIS)

    Berryman, J.G.

    1986-01-01

    The low-frequency limit of Biot's theory of fluid-saturated porous media predicts that the coefficients for viscous attenuation of shear waves and of the fast compressional wave are proportional to the fluid permeability. Although the observed attenuation is generally in qualitative agreement with the theory, the magnitude of the observed attenuation coefficient in rocks is often more than an order of magnitude higher than expected. This apparent dilemma can be resolved without invoking other attenuation mechanisms if the intrinsic permeability of the rock is inhomogeneous and varies widely in magnitude. A simple calculation of the overall behavior of a layered porous material using local-flow Biot theory shows that the effective permeability for attenuation is the mean of the constituent permeabilities while the effective permeability for fluid flow is the harmonic mean. When the range of variation in the local permeability is one or more orders of magnitude, this difference in averaging method can easily explain some of the observed discrepancies

  7. Toxicity of tritium

    International Nuclear Information System (INIS)

    Dobson, R.L.

    1979-01-01

    Among radionuclides of importance in atomic energy, 3 H has relatively low toxicity. The main health and environmental worry is the possibility that significant biological effects may follow from protracted exposure to low concentrations in water. To examine this possible hazard and measure toxicity at low tritium concentrations, chronic exposure studies were done on mice and monkeys. During vulnerable developmental periods animals were exposed to 3 HOH, and mice were exposed also to 60 Co gamma irradiation and energy-related chemical agents. The biological endpoint measured was the irreversible loss of female germ cells. Effects from tritium were observed at surprisingly low concentrations where 3 H was found more damaging than previously thought. Comparisons between tritium and gamma radiation showed the relative biological effectiveness (RBE) to be greater than 1 and to reach approximately 3 at very low exposures. For perspective, other comparisons were made: between radiation and chemical agents, which revealed parallels in action on germ cells, and between pre- and postnatal exposure, which warn of possible special hazard to the fetus from both classes of energy-related byproducts

  8. Toxic compounds in honey.

    Science.gov (United States)

    Islam, Md Nazmul; Khalil, Md Ibrahim; Islam, Md Asiful; Gan, Siew Hua

    2014-07-01

    There is a wealth of information about the nutritional and medicinal properties of honey. However, honey may contain compounds that may lead to toxicity. A compound not naturally present in honey, named 5-hydroxymethylfurfural (HMF), may be formed during the heating or preservation processes of honey. HMF has gained much interest, as it is commonly detected in honey samples, especially samples that have been stored for a long time. HMF is a compound that may be mutagenic, carcinogenic and cytotoxic. It has also been reported that honey can be contaminated with heavy metals such as lead, arsenic, mercury and cadmium. Honey produced from the nectar of Rhododendron ponticum contains alkaloids that can be poisonous to humans, while honey collected from Andromeda flowers contains grayanotoxins, which can cause paralysis of limbs in humans and eventually leads to death. In addition, Melicope ternata and Coriaria arborea from New Zealand produce toxic honey that can be fatal. There are reports that honey is not safe to be consumed when it is collected from Datura plants (from Mexico and Hungary), belladonna flowers and Hyoscamus niger plants (from Hungary), Serjania lethalis (from Brazil), Gelsemium sempervirens (from the American Southwest), Kalmia latifolia, Tripetalia paniculata and Ledum palustre. Although the symptoms of poisoning due to honey consumption may differ depending on the source of toxins, most common symptoms generally include dizziness, nausea, vomiting, convulsions, headache, palpitations or even death. It has been suggested that honey should not be considered a completely safe food. Copyright © 2013 John Wiley & Sons, Ltd.

  9. Thallium toxicity in humans.

    Science.gov (United States)

    Cvjetko, Petra; Cvjetko, Ivan; Pavlica, Mirjana

    2010-03-01

    Thallium is a naturally occurring trace element, widely distributed in the earth's crust, but at very low concentrations. It does not have a known biological use and does not appear to be an essential element for life. It has been considered one of the most toxic heavy metals.Occasionally, there are reports on thallium poisoning as results of suicide or murder attempt or accident. The main threat to humans is through occupational exposure, environmental contamination, and accumulation in food, mainly in vegetables grown on contaminated soil. Increasing use in emerging new technologies and demanding high-tech industry constantly raise concern about exposure risk to all living organisms. Thallium is considered a cumulative poison that can cause adverse health effects and degenerative changes in many organs. The effects are the most severe in the nervous system. The exact mechanism of thallium toxicity still remains unknown, although impaired glutathione metabolism, oxidative stress, and disruption of potassium-regulated homeostasis may play a role. The lack of data about mutagenic, carcinogenic, or teratogenic effects of thallium compounds in humans calls for further research.

  10. Molecular toxicity of nanomaterials.

    Science.gov (United States)

    Chang, Xue-Ling; Yang, Sheng-Tao; Xing, Gengmei

    2014-10-01

    With the rapid developments in the fields of nanoscience and nanotechnlogy, more and more nanomaterials and their based consumer products have been used into our daily life. The safety concerns of nanomaterials have been well recognized by the scientific community and the public. Molecular mechanism of interactions between nanomaterials and biosystems is the most essential topic and final core of the biosafety. In the last two decades, nanotoxicology developed very fast and toxicity phenomena of nanomaterials have been reported. To achieve better understanding and detoxication of nanomaterials, thorough studies of nanotoxicity at molecular level are important. The interactions between nanomaterials and biomolecules have been widely investigated as the first step toward the molecular nanotoxicology. The consequences of such interactions have been discussed in the literature. Besides this, the chemical mechanism of nanotoxicology is gaining more attention, which would lead to a better design of nontoxic nanomaterials. In this review, we focus on the molecular nanotoxicology and explore the toxicity of nanomaterials at molecular level. The molecular level studies of nanotoxicology are summarized and the published nanotoxicological data are revisited.

  11. Attenuation of the gamma rays in tissues

    International Nuclear Information System (INIS)

    Arcos P, A.; Rodriguez N, S.; Pinedo S, A.; Amador V, P.; Chacon R, A.; Vega C, H.R.

    2005-01-01

    The mass and lineal attenuation coefficient and of hepatic tissue, muscular, osseous and of brain before gamma rays of 10 -3 to 10 5 MeV were calculated. For the case of the osseous tissue the calculation was made for the cartilage, the cortical tissue and the bone marrow. During the calculations the elementary composition of the tissues of human origin was used. The calculations include by separate the Photoelectric effect, the Compton scattering and the Pair production, as well as the total. For to establish a comparison with the attenuation capacities, the coefficients of the water, the aluminum and the lead also were calculated. The study was complemented measuring the attenuation coefficient of hepatic tissue of bovine before gamma rays of 0.662 MeV of a source of 137 Cs. The measurement was made through of an experiment of photons transmission through samples frozen of hepatic tissue and with a Geiger-Mueller detector. (Author)

  12. Electromagnetic Wave Attenuation in Atmospheric Pressure Plasma

    International Nuclear Information System (INIS)

    Zhang Shu; Hu Xiwei; Liu Minghai; Luo Fang; Feng Zelong

    2007-01-01

    When an electromagnetic (EM) wave propagates in an atmospheric pressure plasma (APP) layer, its attenuation depends on the APP parameters such as the layer width, the electron density and its profile and collision frequency between electrons and neutrals. This paper proposes that a combined parameter-the product of the line average electron density n-bar and width d of the APP layer (i.e., the total number of electrons in a unit volume along the wave propagation path) can play a more explicit and decisive role in the wave attenuation than any of the above individual parameters does. The attenuation of the EM wave via the product of n-bar and d with various collision frequencies between electrons and neutrals is presented

  13. Natural attenuation of metals and radionuclides - An overview of the Sandia/DOE approach

    International Nuclear Information System (INIS)

    Waters, R.D.; Brady, P.V.; Borns, D.J.

    1998-02-01

    Sandia National Laboratories is developing guidelines that outline the technical basis for relying on natural attenuation for the remediation of metals and radionuclide-contaminated soils and groundwaters at US Department of Energy (DOE) sites for those specific cases where natural processes are effective at ameliorating soil and groundwater toxicity. Remediation by monitored natural attenuation (MNA) requires a clear identification of the specific reaction(s) by which contaminant levels are made less available as well as considerable long-term monitoring. Central to MNA is the development of a conceptual model describing the biogeochemical behavior of contaminant(s) in the subsurface. The conceptual model will be used to make testable predictions of contaminant availability over time. In many cases, comparison between this prediction and field measurements will provide the test of whether MNA is to be implemented. As a result, development of the conceptual model should guide site characterization activities as well as long-term monitoring

  14. Effect of natural organic matter on the photo-induced toxicity of titanium dioxide nanoparticles.

    Science.gov (United States)

    Wormington, Alexis M; Coral, Jason; Alloy, Matthew M; Delmarè, Carmen L; Mansfield, Charles M; Klaine, Stephen J; Bisesi, Joseph H; Roberts, Aaron P

    2017-06-01

    Nano-titanium dioxide (TiO 2 ) is the most widely used form of nanoparticles in commercial industry and comes in 2 main configurations: rutile and anatase. Rutile TiO 2 is used in ultraviolet (UV) screening applications, whereas anatase TiO 2 crystals have a surface defect that makes them photoreactive. There are numerous reports in the literature of photo-induced toxicity to aquatic organisms following coexposure to anatase nano-TiO 2 and UV. All natural freshwater contains varying amounts of natural organic matter (NOM), which can drive UV attenuation and quench reactive oxygen species (ROS) in aquatic ecosystems. The present research examined how NOM alters the photo-induced toxicity of anatase nano-TiO 2 . Daphnia magna neonates were coexposed to NOM and photoexcited anatase nano-TiO 2 for 48 h. Natural organic matter concentrations as low as 4 mg/L reduced anatase nano-TiO 2 toxicity by nearly 100%. These concentrations of NOM attenuated UV by <10% in the exposure system. However, ROS production measured using a fluorescence assay was significantly reduced in a NOM concentration--dependent manner. Taken together, these data suggest that NOM reduces anatase nano-TiO 2 toxicity via an ROS quenching mechanism and not by attenuation of UV. Environ Toxicol Chem 2017;36:1661-1666. © 2016 SETAC. © 2016 SETAC.

  15. Wild lettuce (Lactuca virosa) toxicity

    OpenAIRE

    Besharat, Sima; Besharat, Mahsa; Jabbari, Ali

    2009-01-01

    Wild lettuce (Lactuca virosa) can cause toxic effects when eaten. Wild lettuce grows in the north of Iran and some natives consume it unaware of its adverse side effects. We describe eight patients with manifestations of wild lettuce toxicity, admitted to a general hospital affiliated to the Golestan University of Medical Sciences. All the patients recovered (although one had to spend 48 h in the intensive care unit) and no chronic complications were reported. A clinical suspicion of toxicity...

  16. Cyclophosphamide-induced pulmonary toxicity

    International Nuclear Information System (INIS)

    Siemann, D.W.; Macler, L.; Penney, D.P.

    1986-01-01

    Unlike radiation effects, pulmonary toxicity following drug treatments may develop soon after exposure. The dose-response relationship between Cyclophosphamide and lung toxicity was investigated using increased breathing frequency assays used successfully for radiation induced injury. The data indicate that release of protein into the alveolus may play a significant role in Cy induced pulmonary toxicity. Although the mechanism responsible for the increased alveolar protein is as yet not identified, the present findings suggest that therapeutic intervention to inhibit protein release may be an approach to protect the lungs from toxic effects. (UK)

  17. Natural mutations in a Staphylococcus aureus virulence regulator attenuate cytotoxicity but permit bacteremia and abscess formation

    Science.gov (United States)

    Das, Sudip; Lindemann, Claudia; Young, Bernadette C.; Muller, Julius; Österreich, Babett; Ternette, Nicola; Winkler, Ann-Cathrin; Paprotka, Kerstin; Reinhardt, Richard; Allen, Elizabeth; Flaxman, Amy; Yamaguchi, Yuko; Rollier, Christine S.; van Diemen, Pauline; Blättner, Sebastian; Remmele, Christian W.; Selle, Martina; Dittrich, Marcus; Müller, Tobias; Vogel, Jörg; Ohlsen, Knut; Crook, Derrick W.; Massey, Ruth; Wilson, Daniel J.; Rudel, Thomas; Wyllie, David H.; Fraunholz, Martin J.

    2016-01-01

    Staphylococcus aureus is a major bacterial pathogen, which causes severe blood and tissue infections that frequently emerge by autoinfection with asymptomatically carried nose and skin populations. However, recent studies report that bloodstream isolates differ systematically from those found in the nose and skin, exhibiting reduced toxicity toward leukocytes. In two patients, an attenuated toxicity bloodstream infection evolved from an asymptomatically carried high-toxicity nasal strain by loss-of-function mutations in the gene encoding the transcription factor repressor of surface proteins (rsp). Here, we report that rsp knockout mutants lead to global transcriptional and proteomic reprofiling, and they exhibit the greatest signal in a genome-wide screen for genes influencing S. aureus survival in human cells. This effect is likely to be mediated in part via SSR42, a long-noncoding RNA. We show that rsp controls SSR42 expression, is induced by hydrogen peroxide, and is required for normal cytotoxicity and hemolytic activity. Rsp inactivation in laboratory- and bacteremia-derived mutants attenuates toxin production, but up-regulates other immune subversion proteins and reduces lethality during experimental infection. Crucially, inactivation of rsp preserves bacterial dissemination, because it affects neither formation of deep abscesses in mice nor survival in human blood. Thus, we have identified a spontaneously evolving, attenuated-cytotoxicity, nonhemolytic S. aureus phenotype, controlled by a pleiotropic transcriptional regulator/noncoding RNA virulence regulatory system, capable of causing S. aureus bloodstream infections. Such a phenotype could promote deep infection with limited early clinical manifestations, raising concerns that bacterial evolution within the human body may contribute to severe infection. PMID:27185949

  18. Lovastatin attenuates ionizing radiation-induced normal tissue damage in vivo

    International Nuclear Information System (INIS)

    Ostrau, Christian; Huelsenbeck, Johannes; Herzog, Melanie; Schad, Arno; Torzewski, Michael; Lackner, Karl J.; Fritz, Gerhard

    2009-01-01

    Background and purpose: HMG-CoA-reductase inhibitors (statins) are widely used lipid-lowering drugs. Moreover, they have pleiotropic effects on cellular stress responses, proliferation and apoptosis in vitro. Here, we investigated whether lovastatin attenuates acute and subchronic ionizing radiation-induced normal tissue toxicity in vivo. Materials and methods: Four hours to 24 h after total body irradiation (6 Gy) of Balb/c mice, acute pro-inflammatory and pro-fibrotic responses were analyzed. To comprise subchronic radiation toxicity, mice were irradiated twice with 2.5 Gy and analyses were performed 3 weeks after the first radiation treatment. Molecular markers of inflammation and fibrosis as well as organ toxicities were measured. Results: Lovastatin attenuated IR-induced activation of NF-κB, mRNA expression of cell adhesion molecules and mRNA expression of pro-inflammatory and pro-fibrotic marker genes (i.e. TNFα, IL-6, TGFβ, CTGF, and type I and type III collagen) in a tissue- and time-dependent manner. γH2AX phosphorylation stimulated by IR was not affected by lovastatin, indicating that the statin has no major impact on the induction of DNA damage in vivo. Radiation-induced thrombopenia was significantly alleviated by lovastatin. Conclusions: Lovastatin inhibits both acute and subchronic IR-induced pro-inflammatory and pro-fibrotic responses and cell death in normal tissue in vivo. Therefore, lovastatin might be useful for selectively attenuating acute and subchronic normal tissue damage caused by radiotherapy.

  19. E-Cigarette Toxicity?

    Science.gov (United States)

    Tegin, Gulay; Mekala, Hema Madhuri; Sarai, Simrat Kaur; Lippmann, Steven

    2018-01-01

    Tobacco smoking is the most preventable cause of morbidity and mortality. In just a few short years, electronic cigarettes (e-cigarettes) have become increasingly popular, especially for younger individuals. Many people believe that e-cigarettes are safe. The inhaled aerosols of e-cigarettes contain numerous potential toxicities, some of which could be dangerous for health with long-term use. The safety of prolonged aerosol exposure is not known. The use of e-cigarettes as a harm-reduction tool at stopping tobacco smoking is not uniformly successful. E-cigarettes may be safer than tobacco products, but repeated prolonged exposure to their aerosols has its own considerable potential risk. The long-term health consequences of their use remain to be established. Physicians should vigorously discourage the use of e-cigarettes and tobacco products, with special emphasis on abstinence for younger people and during pregnancy or lactation.

  20. Developmental toxicity of low generation PAMAM dendrimers in zebrafish

    International Nuclear Information System (INIS)

    King Heiden, Tisha C.; Dengler, Emelyne; Kao, Weiyuan John; Heideman, Warren; Peterson, Richard E.

    2007-01-01

    Biological molecules and intracellular structures operate at the nanoscale; therefore, development of nanomedicines shows great promise for the treatment of disease by using targeted drug delivery and gene therapies. PAMAM dendrimers, which are highly branched polymers with low polydispersity and high functionality, provide an ideal architecture for construction of effective drug carriers, gene transfer devices and imaging of biological systems. For example, dendrimers bioconjugated with selective ligands such as Arg-Gly-Asp (RGD) would theoretically target cells that contain integrin receptors and show potential for use as drug delivery devices. While RGD-conjugated dendrimers are generally considered not to be cytotoxic, there currently exists little information on the risks that such materials pose to human health. In an effort to compliment and extend the knowledge gleaned from cell culture assays, we have used the zebrafish embryo as a rapid, medium throughput, cost-effective whole-animal model to provide a more comprehensive and predictive developmental toxicity screen for nanomaterials such as PAMAM dendrimers. Using the zebrafish embryo, we have assessed the developmental toxicity of low generation (G3.5 and G4) PAMAM dendrimers, as well as RGD-conjugated forms for comparison. Our results demonstrate that G4 dendrimers, which have amino functional groups, are toxic and attenuate growth and development of zebrafish embryos at sublethal concentrations; however, G3.5 dendrimers, with carboxylic acid terminal functional groups, are not toxic to zebrafish embryos. Furthermore, RGD-conjugated G4 dendrimers are less potent in causing embryo toxicity than G4 dendrimers. RGD-conjugated G3.5 dendrimers do not elicit toxicity at the highest concentrations tested and warrant further study for use as a drug delivery device

  1. Children's Ability to Recognise Toxic and Non-Toxic Fruits

    Science.gov (United States)

    Fancovicova, Jana; Prokop, Pavol

    2011-01-01

    Children's ability to identify common plants is a necessary prerequisite for learning botany. However, recent work has shown that children lack positive attitudes toward plants and are unable to identify them. We examined children's (aged 10-17) ability to discriminate between common toxic and non-toxic plants and their mature fruits presented in…

  2. GPR measurements of attenuation in concrete

    Energy Technology Data Exchange (ETDEWEB)

    Eisenmann, David, E-mail: djeisen@cnde.iastate.edu; Margetan, Frank J., E-mail: djeisen@cnde.iastate.edu; Pavel, Brittney, E-mail: djeisen@cnde.iastate.edu [Center for Nondestructive Evaluation, Iowa State University, 1915 Scholl Road, Ames, IA 50011-3042 (United States)

    2015-03-31

    Ground-penetrating radar (GPR) signals from concrete structures are affected by several phenomenon, including: (1) transmission and reflection coefficients at interfaces; (2) the radiation patterns of the antenna(s) being used; and (3) the material properties of concrete and any embedded objects. In this paper we investigate different schemes for determining the electromagnetic (EM) attenuation of concrete from measured signals obtained using commercially-available GPR equipment. We adapt procedures commonly used in ultrasonic inspections where one compares the relative strengths of two or more signals having different travel paths through the material of interest. After correcting for beam spread (i.e., diffraction), interface phenomena, and equipment amplification settings, any remaining signal differences are assumed to be due to attenuation thus allowing the attenuation coefficient (say, in dB of loss per inch of travel) to be estimated. We begin with a brief overview of our approach, and then discuss how diffraction corrections were determined for our two 1.6 GHz GPR antennas. We then present results of attenuation measurements for two types of concrete using both pulse/echo and pitch/catch measurement setups.

  3. Mirtazapine attenuates cocaine seeking in rats.

    Science.gov (United States)

    Barbosa-Méndez, Susana; Leff, Phillipe; Arías-Caballero, Adriana; Hernández-Miramontes, Ricardo; Heinze, Gerardo; Salazar-Juárez, Alberto

    2017-09-01

    Relapse to cocaine use is a major problem in the clinical treatment of cocaine addiction. Antidepressants have been studied for their therapeutic potential to treat cocaine use disorder. Research has suggested that antidepressants attenuate both drug craving and the re-acquisition of drug-seeking and drug-taking behaviors. This study examined the efficacy of mirtazapine, an antidepressant/anxiolytic, in decreasing cocaine seeking in rats. We used the cocaine self-administration paradigm to assess the effects of mirtazapine on rats trained to self-administer cocaine or food under a fixed-ratio schedule. Mirtazapine (30 mg/kg, i.p.) was administered during extinction. Mirtazapine significantly attenuated non-reinforced lever-press responses during extinction. Moreover, the mirtazapine dosed for 30 days during extinction produced sustained attenuation of lever-press responses during re-acquisition of cocaine self-administration, without changing food-seeking behavior. Our results showed that mirtazapine attenuated the re-acquisition of cocaine-seeking responses. Our study pointed to the efficacy of mirtazapine in reducing the risk of drug relapse during abstinence, suggesting for its potential use as a novel pharmacological agent to treat drug abuse. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Controlled Attenuation Parameter And Alcoholic Hepatic Steatosis

    DEFF Research Database (Denmark)

    Thiele, Maja; Rausch, Vanessa; Fluhr, Gabriele

    2018-01-01

    BACKGROUND AND AIMS: Controlled attenuation parameter (CAP) is a novel non-invasive measure of hepatic steatosis, but has not been evaluated in alcoholic liver disease. We therefore aimed to validate CAP for assessment of biopsy-verified alcoholic steatosis and to study the effect of alcohol deto...

  5. Heat-accelerated radioinactivation of attenuated poliovirus

    International Nuclear Information System (INIS)

    Dugan, V.L.; Trujillo, R.

    1975-01-01

    Attenuated poliovirus is inactivated in a synergistic manner when exposed simultaneously to heat and ionizing radiation. The synergistic response is observed in both the thermally labile and stable forms of the virus. A three-term kinetic model may be used to describe the inactivation response of the virus in a thermal and/or ionizing radiation environment. (orig.) [de

  6. Ultrasonic attenuation in rare-earth monoarsenides

    Indian Academy of Sciences (India)

    2015-11-27

    Home; Journals; Pramana – Journal of Physics; Volume 86; Issue 6. Ultrasonic attenuation in rare-earth monoarsenides .... Proceedings of the International Workshop/Conference on Computational Condensed Matter Physics and Materials Science (IWCCMP-2015). Posted on November 27, 2015. Guest Editors: Anurag ...

  7. GPR measurements of attenuation in concrete

    Science.gov (United States)

    Eisenmann, David; Margetan, Frank J.; Pavel, Brittney

    2015-03-01

    Ground-penetrating radar (GPR) signals from concrete structures are affected by several phenomenon, including: (1) transmission and reflection coefficients at interfaces; (2) the radiation patterns of the antenna(s) being used; and (3) the material properties of concrete and any embedded objects. In this paper we investigate different schemes for determining the electromagnetic (EM) attenuation of concrete from measured signals obtained using commercially-available GPR equipment. We adapt procedures commonly used in ultrasonic inspections where one compares the relative strengths of two or more signals having different travel paths through the material of interest. After correcting for beam spread (i.e., diffraction), interface phenomena, and equipment amplification settings, any remaining signal differences are assumed to be due to attenuation thus allowing the attenuation coefficient (say, in dB of loss per inch of travel) to be estimated. We begin with a brief overview of our approach, and then discuss how diffraction corrections were determined for our two 1.6 GHz GPR antennas. We then present results of attenuation measurements for two types of concrete using both pulse/echo and pitch/catch measurement setups.

  8. GPR measurements of attenuation in concrete

    International Nuclear Information System (INIS)

    Eisenmann, David; Margetan, Frank J.; Pavel, Brittney

    2015-01-01

    Ground-penetrating radar (GPR) signals from concrete structures are affected by several phenomenon, including: (1) transmission and reflection coefficients at interfaces; (2) the radiation patterns of the antenna(s) being used; and (3) the material properties of concrete and any embedded objects. In this paper we investigate different schemes for determining the electromagnetic (EM) attenuation of concrete from measured signals obtained using commercially-available GPR equipment. We adapt procedures commonly used in ultrasonic inspections where one compares the relative strengths of two or more signals having different travel paths through the material of interest. After correcting for beam spread (i.e., diffraction), interface phenomena, and equipment amplification settings, any remaining signal differences are assumed to be due to attenuation thus allowing the attenuation coefficient (say, in dB of loss per inch of travel) to be estimated. We begin with a brief overview of our approach, and then discuss how diffraction corrections were determined for our two 1.6 GHz GPR antennas. We then present results of attenuation measurements for two types of concrete using both pulse/echo and pitch/catch measurement setups

  9. Anethum Graveolens Linn (Umbelliferae) Extract Attenuates Stress ...

    African Journals Online (AJOL)

    Anethum Graveolens Linn (Umbelliferae) Extract Attenuates Stress-induced Urinary Biochemical Changes and Improves Cognition in Scopolamineinduced Amnesic Rats. ... Conclusion: The aqueous extract of A. graveolens exhibited significant anti-stress, antioxidant and memory enhancing activities. The study provides a ...

  10. Electron attenuation characteristics of LiF

    Energy Technology Data Exchange (ETDEWEB)

    Paliwal, B R [Wisconsin Univ., Madison (USA). Div. of Clinical Oncology; Almond, P R

    1976-08-01

    The results of a study, indicating the exponential nature of the attenuation of electrons in LiF, are reported. This conclusion holds good not only for the monoenergetic electrons obtained from several pure ..beta.. emitters but also for the high energy electron beams delivered by radiotherapy facilities.

  11. Microwave attenuation with composite of copper microwires

    International Nuclear Information System (INIS)

    Gorriti, A.G.; Marin, P.; Cortina, D.; Hernando, A.

    2010-01-01

    It is shown that copper microwires composite media attenuates microwave reflection of metallic surfaces. We show how the distance to the metallic surface, as well as the length and volume fraction of microwires, determine the frequency of maximum absorption and the return loss level. Furthermore, we were able to fit the experimental results with a theoretical model based on Maxwell-Garnett mixing formula.

  12. Microwave attenuation with composite of copper microwires

    Energy Technology Data Exchange (ETDEWEB)

    Gorriti, A.G.; Marin, P. [Instituto de Magnetismo Aplicado, (UCM-ADIF-CSIC) and Departamento de Fisica de Materiales (UCM). P.O. Box 155, Las Rozas, Madrid 28230 (Spain); Cortina, D. [Micromag S.L., Las Rozas, Madrid 28230 (Spain); Hernando, A., E-mail: antonio.hernando@adif.e [Instituto de Magnetismo Aplicado, (UCM-ADIF-CSIC) and Departamento de Fisica de Materiales (UCM). P.O. Box 155, Las Rozas, Madrid 28230 (Spain); Micromag S.L., Las Rozas, Madrid 28230 (Spain)

    2010-05-15

    It is shown that copper microwires composite media attenuates microwave reflection of metallic surfaces. We show how the distance to the metallic surface, as well as the length and volume fraction of microwires, determine the frequency of maximum absorption and the return loss level. Furthermore, we were able to fit the experimental results with a theoretical model based on Maxwell-Garnett mixing formula.

  13. Touch Attenuates Infants' Physiological Reactivity to Stress

    Science.gov (United States)

    Feldman, Ruth; Singer, Magi; Zagoory, Orna

    2010-01-01

    Animal studies demonstrate that maternal touch and contact regulate infant stress, and handling during periods of maternal deprivation attenuates the stress response. To measure the effects of touch on infant stress reactivity during simulated maternal deprivation, 53 dyads were tested in two paradigms: still-face (SF) and still-face with maternal…

  14. Analysis of biological samples by x-ray attenuation measurements

    International Nuclear Information System (INIS)

    Cesareo, R.

    1988-01-01

    Over the last few years there has been an increasing interest in X-ray attenuation measurements, mainly due to the enormous development of computer assisted tomography (CAT). With CAT, analytical information concerning the density and the mean atomic number distributions in a sample is deduced from a large number of attenuation measurements. Particular transmission methods developed, based on the differential attenuation method are discussed. The theoretical background for attenuation of radiation and for differential attenuation of radiation is given. Details about the generation of monoenergetic X-rays are discussed. Applications of attenuation measurements in the field of Medicine are presented

  15. Active inference, sensory attenuation and illusions.

    Science.gov (United States)

    Brown, Harriet; Adams, Rick A; Parees, Isabel; Edwards, Mark; Friston, Karl

    2013-11-01

    Active inference provides a simple and neurobiologically plausible account of how action and perception are coupled in producing (Bayes) optimal behaviour. This can be seen most easily as minimising prediction error: we can either change our predictions to explain sensory input through perception. Alternatively, we can actively change sensory input to fulfil our predictions. In active inference, this action is mediated by classical reflex arcs that minimise proprioceptive prediction error created by descending proprioceptive predictions. However, this creates a conflict between action and perception; in that, self-generated movements require predictions to override the sensory evidence that one is not actually moving. However, ignoring sensory evidence means that externally generated sensations will not be perceived. Conversely, attending to (proprioceptive and somatosensory) sensations enables the detection of externally generated events but precludes generation of actions. This conflict can be resolved by attenuating the precision of sensory evidence during movement or, equivalently, attending away from the consequences of self-made acts. We propose that this Bayes optimal withdrawal of precise sensory evidence during movement is the cause of psychophysical sensory attenuation. Furthermore, it explains the force-matching illusion and reproduces empirical results almost exactly. Finally, if attenuation is removed, the force-matching illusion disappears and false (delusional) inferences about agency emerge. This is important, given the negative correlation between sensory attenuation and delusional beliefs in normal subjects--and the reduction in the magnitude of the illusion in schizophrenia. Active inference therefore links the neuromodulatory optimisation of precision to sensory attenuation and illusory phenomena during the attribution of agency in normal subjects. It also provides a functional account of deficits in syndromes characterised by false inference

  16. Hydroxycut-induced Liver Toxicity

    African Journals Online (AJOL)

    hanumantp

    Annals of Medical and Health Sciences Research | Jan-Feb 2014 | Vol 4 ... supplements can be responsible for documented or undocumented adverse drug effects. The ... Keywords: Hydroxycut, Liver toxicity, Nutritional supplements ... Caffeine anhydrous: 200 mg* ... series and review of liver toxicity from herbal weight loss.

  17. One Health and Toxic Cyanobacteria

    Science.gov (United States)

    One Health and toxic cyanobacteria Blooms of toxic freshwater blue-green algae or cyanobacteria (HABs) have been in the news after HABs associated with human and animal health problems have been reported in Florida, California and Utah during 2016. HABs occur in warm, slow moving...

  18. Toxic Leadership in Educational Organizations

    Science.gov (United States)

    Green, James E.

    2014-01-01

    While research on the traits and skills of effective leaders is plentiful, only recently has the phenomenon of toxic leadership begun to be investigated. This research report focuses on toxic leadership in educational organizations--its prevalence, as well as the characteristics and early indicators. Using mixed methods, the study found four…

  19. Building a developmental toxicity ontology.

    Science.gov (United States)

    Baker, Nancy; Boobis, Alan; Burgoon, Lyle; Carney, Edward; Currie, Richard; Fritsche, Ellen; Knudsen, Thomas; Laffont, Madeleine; Piersma, Aldert H; Poole, Alan; Schneider, Steffen; Daston, George

    2018-04-03

    As more information is generated about modes of action for developmental toxicity and more data are generated using high-throughput and high-content technologies, it is becoming necessary to organize that information. This report discussed the need for a systematic representation of knowledge about developmental toxicity (i.e., an ontology) and proposes a method to build one based on knowledge of developmental biology and mode of action/ adverse outcome pathways in developmental toxicity. This report is the result of a consensus working group developing a plan to create an ontology for developmental toxicity that spans multiple levels of biological organization. This report provide a description of some of the challenges in building a developmental toxicity ontology and outlines a proposed methodology to meet those challenges. As the ontology is built on currently available web-based resources, a review of these resources is provided. Case studies on one of the most well-understood morphogens and developmental toxicants, retinoic acid, are presented as examples of how such an ontology might be developed. This report outlines an approach to construct a developmental toxicity ontology. Such an ontology will facilitate computer-based prediction of substances likely to induce human developmental toxicity. © 2018 Wiley Periodicals, Inc.

  20. Polish Toxic Currency Options

    Directory of Open Access Journals (Sweden)

    Waldemar Gontarski

    2009-06-01

    Full Text Available Toxic currency options are defined on the basis of the opposition to the nature (essence of an option contract, which is justified in terms of norms founded on the general law clause of characteristics (nature of a relation (which represents an independent premise for imposing restrictions on the freedom of contracts. So-understood toxic currency options are unlawful. Indeed they contravene iuris cogentis regulations. These include for instance option contracts, which are concluded with a bank, if the bank has not informed about option risk before concluding the contract; or the barrier options, which focus only on the protection of bank’s interests. Therefore, such options may appear to be invalid. Therefore, performing contracts for toxic currency options may be qualified as a criminal mismanagement. For the sake of security, the manager should then take into consideration filing a claim for stating invalidity (which can be made in a court verdict. At the same time, if the supervisory board member in a commercial company, who can also be a subject to mismanagement offences, commits an omission involving lack of reaction (for example, if he/she fails to notify of the suspected offence committed by the management board members acting to the company’s detriment when the management board makes the company conclude option contracts which are charged with absolute invalidity the supervisory board member so acting may be considered to act to the company’s detriment. In the most recent Polish jurisprudence and judicature the standard of a “good host” is treated to be the last resort for determining whether the manager’s powers resulting from criminal regulations were performed. The manager of the exporter should not, as a rule, issue any options. Issuing options always means assuming an obligation. In the case of currency put options it is an absolute obligation to purchase a given amount in euro at exchange rate set in advance. On the

  1. Toxic releases from power plants

    International Nuclear Information System (INIS)

    Rubin, E.S.

    1999-01-01

    Beginning in 1998, electric power plants burning coal or oil must estimate and report their annual releases of toxic chemicals listed in the Toxics Release Inventory (TRI) published by the US Environmental Protection Agency (EPA). This paper identifies the toxic chemicals of greatest significance for the electric utility sector and develops quantitative estimates of the toxic releases reportable to the TRI for a representative coal-fired power plant. Key factors affecting the magnitude and types of toxic releases for individual power plants also are discussed. A national projection suggests that the magnitude of electric utility industry releases will surpass those of the manufacturing industries which current report to the TRI. Risk communication activities at the community level will be essential to interpret and provide context for the new TRI results

  2. VARIATIONS IN REPRODUCTIVE TOXICANT IDENTIFICATION

    Energy Technology Data Exchange (ETDEWEB)

    Simmons, F

    2008-05-13

    Reproductive toxicants are a very important class of compounds. They present unique hazards to those of child bearing ages, perform their 'dirty work' using a wide variety of mechanisms on a number of different organs, and are regulatorily important. Because of all of this, properly identifying reproductive toxicants is important, but fraught with difficulty. In this paper we will describe types or reproductive toxicants, their importance, and both mistakes and good practices that people who are not experts in reproductive toxicology may use in their attempts to identify them. Additionally, this paper will focus on chemical reproductive toxicants and will not address biological agents that could affect reproductive toxicity although many principles outlined here could be applied to that endeavor.

  3. Subinhibitory quinupristin/dalfopristin attenuates virulence of Staphylococcus aureus.

    Science.gov (United States)

    Koszczol, Carmen; Bernardo, Katussevani; Krönke, Martin; Krut, Oleg

    2006-09-01

    The semi-synthetic streptogramin quinupristin/dalfopristin antibiotic exerts potent bactericidal activity against Staphylococcus aureus. We investigated whether, like other bactericidal antibiotics used at subinhibitory concentrations, quinupristin/dalfopristin enhances release of toxins by Gram-positive cocci. The activity of quinupristin/dalfopristin on exotoxin release by S. aureus was investigated by 2D SDS-PAGE combined with MALDI-TOF/MS analysis and by western blotting. We show that quinupristin/dalfopristin at subinhibitory concentrations reduces the release of S. aureus factors that induce tumour necrosis factor secretion in macrophages. Furthermore, quinupristin/dalfopristin but not linezolid attenuated S. aureus-mediated killing of infected host cells. When added to S. aureus cultures at different stages of bacterial growth, quinupristin/dalfopristin reduced in a dose-dependent manner the release of specific virulence factors (e.g. autolysin, protein A, alpha- and beta-haemolysins, lipases). In contrast, other presumably non-toxic exoproteins remained unchanged. The results of the present study suggest that subinhibitory quinupristin/dalfopristin inhibits virulence factor release by S. aureus, which might be especially helpful for the treatment of S. aureus infections, where both bactericidal as well as anti-toxin activity may be advantageous.

  4. Chinese Herbal Medicines Attenuate Acute Pancreatitis: Pharmacological Activities and Mechanisms

    Directory of Open Access Journals (Sweden)

    Dong Shang

    2017-04-01

    Full Text Available Acute pancreatitis (AP is a commonly occurring gastrointestinal disorder. An increase in the annual incidence of AP has been observed, and it causes acute hospitalization and high mortality. The diagnosis and treatment guidelines for AP recommend conservative medical treatments focused on reducing pancreatic secretion and secondary injury, as a primary therapeutic approach. Unfortunately, the existing treatment options have limited impact on the incidence and severity of AP due to the complex and multifaceted pathological process of this disease. In recent decades, Chinese herbal medicines (CHMs have been used as efficient therapeutic agents to attenuate AP in Asian countries. Despite early cell culture, animal models, and clinical trials, CHMs are capable of interacting with numerous molecular targets participating in the pathogenesis of AP; however, comprehensive, up-to-date communication in this field is not yet available. This review focuses on the pharmacological activities of CHMs against AP in vitro and in vivo and the underlying mechanisms. A computational prediction of few selected and promising plant-derived molecules (emodin, baicalin, resveratrol, curcumin, ligustrazine, and honokiol to target numerous proteins or networks involved in AP was initially established based on a network pharmacology simulation. Moreover, we also summarized some potential toxic natural products for pancreas in order to more safe and reasonable medication. These breakthrough findings may have important implications for innovative drug research and the future development of treatments for AP.

  5. Anaerobic biodegradability and toxicity of complex or toxicant wastewater

    International Nuclear Information System (INIS)

    Wills Betancur, B.A.

    1995-01-01

    As a first approximation to wastewater classification in susceptibility terms to treatment by anaerobic biological system, anaerobic biodegradability trials are accomplished to leached of sanitary landfill, to wastewater of coffee grain wet treatment plant and to wastewater of fumaric acid recuperation plant. In the last Plant, anaerobic toxicity trials and lethal toxicity on the Daphnia pulex micro-crustacean are made too. Anaerobic biological trials are made continuing the Wageningen University (Holland) Methodology (1.987). Lethal toxicity biological trials are made following the Standard Methods for the Examination of Water and Wastewater(18th edition, 1992). In development of this investigation project is found that fumaric acid recuperation plant leached it has a low anaerobic biodegradability, a high anaerobic toxicity and a high lethal toxicity over Daphnia pulex, for such reasons this leached is cataloged as complex and toxic wastewater. The other hand, wastewater of coffee grain wet treatment plant and wastewater of sanitary landfill they are both highly biodegradability and not-toxic, for such reasons these wastewaters are cataloged as susceptible to treatment by anaerobic biological system

  6. Toxic epidermal necrolysis.

    Science.gov (United States)

    Pereira, Frederick A; Mudgil, Adarsh Vijay; Rosmarin, David M

    2007-02-01

    Toxic epidermal necrolysis (TEN) is an unpredictable, life-threatening drug reaction associated with a 30% mortality. Massive keratinocyte apoptosis is the hallmark of TEN. Cytotoxic T lymphocytes appear to be the main effector cells and there is experimental evidence for involvement of both the Fas-Fas ligand and perforin/granzyme pathways. Optimal treatment for these patients remains to be clarified. Discontinuation of the offending drug and prompt referral to a burn unit are generally agreed upon steps. Beyond that, however, considerable controversy exists. Evidence both pro and con exists for the use of IVIG, systemic corticosteroid, and other measures. There is also evidence suggesting that combination therapies may be of value. All the clinical data, however, is anecdotal or based on observational or retrospective studies. Definitive answers are not yet available. Given the rarity of TEN and the large number of patients required for a study to be statistically meaningful, placebo controlled trials are logistically difficult to accomplish. The absence of an animal model further hampers research into this condition. This article reviews recent data concerning clinical presentation, pathogenesis and treatment of TEN. At the conclusion of this learning activity, participants should have acquired a more comprehensive knowledge of our current understanding of the classification, clinical presentation, etiology, pathophysiology, prognosis, and treatment of TEN.

  7. The toxicity of plutonium

    International Nuclear Information System (INIS)

    Ramsden, D.; Johns, T.F.

    1977-01-01

    Reference is made to recent publications concerned with the radiotoxicity of inhaled insoluble Pu compounds. The publications are a paper by Thorne and Vennart (Nature 263:555 (1976)), a report entitled 'The Toxicity of Plutonium', (London (HMSO), 1975), and the 'Sixth Report of the Royal Commission on Environmental Pollution', (Cmnd. 6618, London (HMSO), 1976). Thorne and Vennart concluded that the previously accepted value for the maximum permissible annual intake (MPAI) of such compounds may be too high by a factor of about five, and a similar conclusion was reached in the other two publications. It is thought by the present authors that the methods which have been used to suggest new values for the MPAI are unduly pessimistic for high-fired PuO 2 ; calculations have been based on the lung model of ICRP Publication 19 'The Metabolism of Compounds of Plutonium and the Other Actinides', (International Commission of Radiological Protection, 1972). This involves concluding that the risks to bone and liver are comparable to those for lung. This is discussed and it is thought that the previously established idea that the lung is the critical organ remains substantially correct for the case of high-fired PuO 2 . (U.K.)

  8. Behavioral effects of ketamine and toxic interactions with psychostimulants

    Directory of Open Access Journals (Sweden)

    Yamamoto Keiichi

    2006-03-01

    Full Text Available Abstract Background The anesthetic drug ketamine (KT has been reported to be an abused drug and fatal cases have been observed in polydrug users. In the present study, considering the possibility of KT-enhanced toxic effects of other drugs, and KT-induced promotion of an overdose without making the subject aware of the danger due to the attenuation of several painful subjective symptoms, the intraperitoneal (i.p. KT-induced alterations in behaviors and toxic interactions with popular co-abused drugs, the psychostimulants cocaine (COC and methamphetamine (MA, were examined in ICR mice. Results A single dose of KT caused hyperlocomotion in a low (30 mg/kg, i.p. dose group, and hypolocomotion followed by hyperlocomotion in a high (100 mg/kg, i.p. dose group. However, no behavioral alterations derived from enhanced stress-related depression or anxiety were observed in the forced swimming or the elevated plus-maze test. A single non-fatal dose of COC (30 mg/kg, i.p. or MA (4 mg/kg, i.p. caused hyperlocomotion, stress-related depression in swimming behaviors in the forced swimming test, and anxiety-related behavioral changes (preference for closed arms in the elevated plus-maze test. For the COC (30 mg/kg or MA (4 mg/kg groups of mice simultaneously co-treated with KT, the psychostimulant-induced hyperlocomotion was suppressed by the high dose KT, and the psychostimulant-induced behavioral alterations in the above tests were reversed by both low and high doses of KT. For the toxic dose COC (70 mg/kg, i.p.- or MA (15 mg/kg, i.p.-only group, mortality and severe seizures were observed in some animals. In the toxic dose psychostimulant-KT groups, KT attenuated the severity of seizures dose-dependently. Nevertheless, the mortality rate was significantly increased by co-treatment with the high dose KT. Conclusion Our results demonstrated that, in spite of the absence of stress-related depressive and anxiety-related behavioral alterations following a single

  9. Improvement of quantitation in SPECT: Attenuation and scatter correction using non-uniform attenuation data

    International Nuclear Information System (INIS)

    Mukai, T.; Torizuka, K.; Douglass, K.H.; Wagner, H.N.

    1985-01-01

    Quantitative assessment of tracer distribution with single photon emission computed tomography (SPECT) is difficult because of attenuation and scattering of gamma rays within the object. A method considering the source geometry was developed, and effects of attenuation and scatter on SPECT quantitation were studied using phantoms with non-uniform attenuation. The distribution of attenuation coefficients (μ) within the source were obtained by transmission CT. The attenuation correction was performed by an iterative reprojection technique. The scatter correction was done by convolution of the attenuation corrected image and an appropriate filter made by line source studies. The filter characteristics depended on μ and SPEC measurement at each pixel. The SPECT obtained by this method showed the most reasonable results than the images reconstructed by other methods. The scatter correction could compensate completely for a 28% scatter components from a long line source, and a 61% component for thick and extended source. Consideration of source geometries was necessary for effective corrections. The present method is expected to be valuable for the quantitative assessment of regional tracer activity

  10. Attenuation of Microbial Stress Due to Nano-Ag and Nano-TiO2 Interactions under Dark Conditions.

    Science.gov (United States)

    Wilke, Carolyn M; Tong, Tiezheng; Gaillard, Jean-François; Gray, Kimberly A

    2016-10-04

    Engineered nanomaterials (ENMs) are incorporated into thousands of commercial products, and their release into environmental systems creates complex mixtures with unknown toxicological outcomes. To explore this scenario, we probe the chemical and toxicological interactions of nanosilver (n-Ag) and nanotitania (n-TiO 2 ) in Lake Michigan water, a natural aqueous medium, under dark conditions. We find that the presence of n-Ag induces a stress response in Escherichia coli, as indicated by a decrease in ATP production observed at low concentrations (in the μg L -1 range), with levels that are environmentally relevant. However, when n-Ag and n-TiO 2 are present together in a mixture, n-TiO 2 attenuates the toxicity of n-Ag at and below 20 μg L -1 by adsorbing Ag + (aq) . We observe, however, that toxic stress cannot be explained by dissolved silver concentrations alone and, therefore, must also depend on silver associated with the nanoscale fraction. Although the attenuating effect of n-TiO 2 on n-Ag's toxicity is limited, this study emphasizes the importance of probing the toxicity of ENM mixtures under environmental conditions to assess how chemical interactions between nanoparticles change the toxicological effects of single ENMs in unexpected ways.

  11. Combined subchronic fluoride-lead intoxication and its attenuation with the help of a complex of bioprotectors.

    Science.gov (United States)

    Katsnelson, B A; Privalova, L I; Kireyeva, Y P; Yeremenko, O S; Sutunkova, M P; Valamina, I E; Varaksin, A N; Panov, V G; Kazmer, J I

    2012-01-01

    Combined toxicity of lead and fluoride has been studied insufficiently, and there is no known information about attempts to inhibit it with any bioprotectors. Lead acetate and sodium fluoride, administered separately or in combination, were injected i.p. to rats at isoeffective sublethal doses 3 times a week for 6 weeks. Some of the rats were exposed to the same combination against the background of oral administration of a bioprotector complex (BPC) comprising pectin, glutamate, and multivitamin/multimineral preparations. Following exposure, functional and biochemical indices and histopathological examinations of the femur of exposed and control rats were evaluated for signs of toxicity. We have shown that with regard to a number of effects on the organism level the combined toxicity of lead and fluoride may be evaluated as additive or even superadditive, but lead reduces fluoride accumulation in the bone, and pathological changes in the bone tissue proved to be less marked for combined exposure compared with separate exposures. The BPC has been demonstrated to attenuate a range of the combined harmful effects of lead and fluoride, including those on the bone tissue. In spite of the fact that fluoride and lead may reciprocally attenuate their harmful effects on the bone tissue in case of combined exposure, they prove to be more toxic for soft tissues just in combination than when administered separately. The development of combined intoxication may be substantially inhibited by means of the tested set of innocuous biologically active agents.

  12. Molecular toxicity mechanism of nanosilver

    Directory of Open Access Journals (Sweden)

    Danielle McShan

    2014-03-01

    Full Text Available Silver is an ancient antibiotic that has found many new uses due to its unique properties on the nanoscale. Due to its presence in many consumer products, the toxicity of nanosilver has become a hot topic. This review summarizes recent advances, particularly the molecular mechanism of nanosilver toxicity. The surface of nanosilver can easily be oxidized by O2 and other molecules in the environmental and biological systems leading to the release of Ag+, a known toxic ion. Therefore, nanosilver toxicity is closely related to the release of Ag+. In fact, it is difficult to determine what portion of the toxicity is from the nano-form and what is from the ionic form. The surface oxidation rate is closely related to the nanosilver surface coating, coexisting molecules, especially thiol-containing compounds, lighting conditions, and the interaction of nanosilver with nucleic acids, lipid molecules, and proteins in a biological system. Nanosilver has been shown to penetrate the cell and become internalized. Thus, nanosilver often acts as a source of Ag+ inside the cell. One of the main mechanisms of toxicity is that it causes oxidative stress through the generation of reactive oxygen species and causes damage to cellular components including DNA damage, activation of antioxidant enzymes, depletion of antioxidant molecules (e.g., glutathione, binding and disabling of proteins, and damage to the cell membrane. Several major questions remain to be answered: (1 the toxic contribution from the ionic form versus the nano-form; (2 key enzymes and signaling pathways responsible for the toxicity; and (3 effect of coexisting molecules on the toxicity and its relationship to surface coating.

  13. Evaluation of genetic diversity between toxic and non toxic Jatropha ...

    African Journals Online (AJOL)

    Massimo

    Indian varieties and a non-toxic variety of Mexican origin by means of about 400 RAPD ... evaluate the level of polymorphism and the capacity to discriminate between the ..... Population genetic software for teaching and research. Mol. Ecol.

  14. Protection against methanol-induced retinal toxicity by LED photostimulation

    Science.gov (United States)

    Whelan, Harry T.; Wong-Riley, Margaret T. T.; Eells, Janis T.

    2002-06-01

    We have initiated experiments designed to test the hypothesis that 670-nm Light-Emitting Diode (LED) exposure will attenuate formate-induced retinal dysfunction in a rodent model of methanol toxicity. Methanol intoxication produces toxic injury to the retina. The toxic metabolite formed in methanol intoxication is formic acid, a mitochondrial toxin known to inhibit cytochrome oxidase activity. 670-nm LED light has been hypothesized to act by stimulating cytochrome oxidase activity. To test this hypothesis, one group of animals was intoxicated with methanol, a second group was intoxicated with methanol and LED-treated and a third group was untreated. LED treatment (670 nm for 1 min 45 seconds equals 50 mW/cm2, 4 joules/cm2) was administered at 5, 25, and 50 hours after the initial dose of methanol. At 72 hours of methanol intoxication, retinal function was assessed by measurement of ERG responses and retinas were prepared for histologic analysis. ERG responses recorded in methanol-intoxicated animals revealed profound attenuation of both rod-dominated and UV-cone mediated responses. In contrast, methanol- intoxicated animals exposed to LED treatment exhibited a nearly complete recovery of rod-dominated ERG responses and a slight improvement of UV-cone mediated ERG responses. LED treatment also protected the retina against the histopathologic changes produced by formate in methanol intoxication. These data provide evidence that LED phototherapy protects the retina against the cytotoxic actions of formate and are consistent with the hypothesis that LED photostimulation improves mitochondrial respiratory chain function.

  15. Toxicity of Uranium Adsorbent Materials using the Microtox Toxicity Test

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jiyeon [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Jeters, Robert T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Gill, Gary A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kuo, Li-Jung [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Bonheyo, George T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-10-01

    The Marine Sciences Laboratory at the Pacific Northwest National Laboratory evaluated the toxicity of a diverse range of natural and synthetic materials used to extract uranium from seawater. The uranium adsorbent materials are being developed as part of the U. S. Department of Energy, Office of Nuclear Energy, Fuel Resources Program. The goal of this effort was to identify whether deployment of a farm of these materials into the marine environment would have any toxic effects on marine organisms.

  16. Overview of recent developments in attenuation models

    International Nuclear Information System (INIS)

    Riera, J.D.

    2001-01-01

    Attenuation equations predict features of the seismic motion, such as the horizontal and vertical peak ground accelerations (PGA), the peak ground velocities (PGV) and the 5% damped spectral acceleration response (SA), in terms of the earthquake magnitude and distance from source to site. Occasionally other factors, like the type of faulting, are considered in the attenuation expressions. An overview of recent developments in this field is presented in the paper, including a discussion of the applicability of various models for short source to site distances. In such a case, i.e. in the neighbourhood of the epicentral region, which is of utmost importance in Nuclear Power Plant applications, the use of two parameters to define the earthquake size is suggested, instead of the single parameter, a magnitude scale. Recent evidence of the importance in such situations of so-called directivity effects, which require a more complete description of the focal mechanism, completes the paper. (author)

  17. P300 is attenuated during dissociative episodes.

    Science.gov (United States)

    Kirino, Eiji

    2006-02-01

    The present study examined the pathophysiology of dissociative phenomena using the P300 component of event-related potentials, quantitative electroencephalography (QEEG), and morphology measures of computed tomography scan. Event-related potentials during an auditory oddball paradigm and QEEG in resting state were recorded. Patients exhibited attenuation of P300 amplitudes compared with controls during dissociative episodes, but exhibited recovery to control levels in remission. Patients had a larger Sylvian fissure-brain ratio than did controls. QEEG findings revealed no significant differences between the patients and controls or between episodes and remission in the patient group. Attenuation of the P300 can be interpreted as the result of a negative feedback loop from the medial temporal lobe to the cortex, which decreases the amount of information flow, allocation of attentional resources, and updating of working memory to avoid both excessive long-term memory system activity in medial temporal lobe and resurgence of affect-laden memories.

  18. Indoor signal attenuation assessment via fuzzy logic

    Directory of Open Access Journals (Sweden)

    Alexandre de Assis Mota

    2011-09-01

    Full Text Available This work focuses on the analysis of signal´s attenuation in indoor environments using a fuzzy logic approach based on the Shadowing Signal Propagation Model (SSPM. The SSPM allows the characterization of the attenuation caused by the environment through the ? parameter present in this model. In addition to this, the Fuzzy Logic provides a form of approximate reasoning that allows the treatment of problems with incomplete, vague and imprecise information. Also, it offers a simple way to obtain a possible solution for a problem using the heuristic knowledge about a particular situation. The results show that the methodology produced satisfactory results, close to the ones yielded by experimental methods.

  19. Attenuation of gamma radiation in concrete shields

    International Nuclear Information System (INIS)

    Azevedo e Souza, A.C. de.

    1978-12-01

    The attenuation characteristics of γ radiation in concrete layers considering their mechanical resistence and densities were determined. A 137 Cs source was used in a 'good geometry' arrangement to eliminate the effects of the buildup factor. The ordinary and the heavy concrete were irradiated and for the latter it was used as additives iron ore and Fe 2 O 3 pellets in various grain sizes. The detection system consisted of a 2' x 2' NaI (Tl) crystal coupled to a photomultiplier tube and the associated electronic equipment. FORTRAN programs were used for determining the absorption coefficients and the attenuation factors. These programs calculate photopeak areas eliminating all contributions due to Compton effect and background. (Author) [pt

  20. Anomalies of ultrasound attenuation in metals under hydrostatic pressure

    International Nuclear Information System (INIS)

    Galkin, A.A.; Datsko, O.I.; Varyukhin, V.N.; Pilipenko, N.P.

    1978-01-01

    Ultrasonic attenuation was measured in polycrystal specimens of molybdenum, chromium and zinc under hydrostatic pressure up to 6 kbar. On the plot of ultrasound attenuation dependence on the pressure in molybdenum the maxima are observed under the pressure of 2 kbar. The anomaly of ultrasound attenuation is shown to connect only with brittle-ductile transtion

  1. A COMPREHENSIVE REVIEW OF TOXIC LEADERSHIP

    Science.gov (United States)

    2016-02-05

    characteristics of a toxic leader , but labels the characteristics - leader types.  Deceptive  Autocratic  Egotistic  Incompetent  Ignorant...3 Characteristics of a Toxic Leader ...5 Table 2: Toxic Leader Characteristics

  2. National Air Toxic Assessments (NATA) Results

    Data.gov (United States)

    U.S. Environmental Protection Agency — The National Air Toxics Assessment was conducted by EPA in 2002 to assess air toxics emissions in order to identify and prioritize air toxics, emission source types...

  3. Toxicity testing of four silver nanoparticle-coated dental castings in 3-D LO2 cell cultures.

    Science.gov (United States)

    Zhao, Yi-Ying; Chu, Qiang; Shi, Xu-Er; Zheng, Xiao-Dong; Shen, Xiao-Ting; Zhang, Yan-Zhen

    To address the controversial issue of the toxicity of dental alloys and silver nanoparticles in medical applications, an in vivo-like LO2 3-D model was constructed within polyvinylidene fluoride hollow fiber materials to mimic the microenvironment of liver tissue. The use of microscopy methods and the measurement of liver-specific functions optimized the model for best cell performances and also proved the superiority of the 3-D LO2 model when compared with the traditional monolayer model. Toxicity tests were conducted using the newly constructed model, finding that four dental castings coated with silver nanoparticles were toxic to human hepatocytes after cell viability assays. In general, the toxicity of both the castings and the coated silver nanoparticles aggravated as time increased, yet the nanoparticles attenuated the general toxicity by preventing metal ion release, especially at high concentrations.

  4. Phonic Attenuation due to Screen-Barriers

    Directory of Open Access Journals (Sweden)

    Vasile Bacria

    2011-10-01

    Full Text Available The technique of noise decreasing admits two basic approaches: an active approach and a passive one. In the frame of passive method one can count the employment of screen-barriers. In this paper we present some considerations on sound attenuation due to screen-barriers emphasizing the elements which influence it. The elucidation of these elements is made by measurements. The obtained results can be applied in every other practical situation concerning the protection against noise.

  5. Mid-European seismic attenuation anomaly

    Czech Academy of Sciences Publication Activity Database

    Málek, Jiří; Brokešová, J.; Vackář, Jiří

    2017-01-01

    Roč. 712, AUG 21 (2017), s. 557-577 ISSN 0040-1951 Grant - others:AV ČR(CZ) StrategieAV21/4 Program:StrategieAV Institutional support: RVO:67985891 Keywords : seismic wave attenuation * peak ground motion * H/V ratio Subject RIV: DC - Siesmology, Volcanology, Earth Structure OBOR OECD: Geology Impact factor: 2.693, year: 2016

  6. Attenuation and scatter correction in SPECT

    International Nuclear Information System (INIS)

    Pant, G.S.; Pandey, A.K.

    2000-01-01

    While passing through matter, photons undergo various types of interactions. In the process, some photons are completely absorbed, some are scattered in different directions with or without any change in their energy and some pass through unattenuated. These unattenuated photons carry the information with them. However, the image data gets corrupted with attenuation and scatter processes. This paper deals with the effect of these two processes in nuclear medicine images and suggests the methods to overcome them

  7. Natural attenuation of biogas in landfill covers

    International Nuclear Information System (INIS)

    Cossu, R.; Privato, A.; Raga, R.

    2005-01-01

    In the risk evaluation of uncontrolled biogas emissions from landfills, the process of natural attenuation in landfill covers assumes a very important role. The capacity of biogas oxidation in the cover soils seems to be the most important control to mitigate the biogas emission during the aftercare period when the biogas collection system might fail. In the present paper laboratory experiences on lab columns to study the biogas oxidation are discussed [it

  8. Radiation attenuation gauge with magnetically coupled source

    International Nuclear Information System (INIS)

    Wallace, S.A.

    1978-01-01

    Disclosed is a radiation attenuation gauge for measuring thickness and density of a material which includes, in combination, a source of gamma radiation contained within a housing of magnetic or ferromagnetic material, and a means for measuring the intensity of gamma radiation. The measuring means has an aperture and magnetic means disposed adjacent to the aperture for attracting and holding the housed source in position before the aperture. The material to be measured is placed between the source and the measuring means

  9. Wave attenuation charcteristics of tethered float system

    Digital Repository Service at National Institute of Oceanography (India)

    Vethamony, P.

    incident wave height transmitted wave height G wave number float mass number of rows of floats drag power transmitted wave power incident wave power 111 112 P. Vethamony float radius wave period time velocity and acceleration of fluid... particles, respectively wave attenuation in percentage displacement, velocity and acceleration of float, respectively amplitude of float displacement added mass damping coefficient fluid particle displacement amplitude of fluid particle displacement...

  10. The attenuation of the periodic table

    International Nuclear Information System (INIS)

    Cook, N.D.

    1990-01-01

    Unique among models of nuclear structure, the face-centered-cubic (FCC) lattice model predicts the attenuation of the periodic table at Z < 110 and the impossibility of superheavy nuclei. The total binding energies of superheavy nuclei in the FCC model (109 < Z < 127) were calculated on the basis of parameters obtained from a least-squares best-fit for 914 nuclei (Z < 99). No indication of increased stability is found for any of the transuranic elements

  11. Broadband Vibration Attenuation Using Hybrid Periodic Rods

    Directory of Open Access Journals (Sweden)

    S. Asiri

    2008-12-01

    Full Text Available This paper presents both theoretically and experimentally a new kind of a broadband vibration isolator. It is a table-like system formed by four parallel hybrid periodic rods connected between two plates. The rods consist of an assembly of periodic cells, each cell being composed of a short rod and piezoelectric inserts. By actively controlling the piezoelectric elements, it is shown that the periodic rods can efficiently attenuate the propagation of vibration from the upper plate to the lower one within critical frequency bands and consequently minimize the effects of transmission of undesirable vibration and sound radiation. In such a system, longitudinal waves can propagate from the vibration source in the upper plate to the lower one along the rods only within specific frequency bands called the "Pass Bands" and wave propagation is efficiently attenuated within other frequency bands called the "Stop Bands". The spectral width of these bands can be tuned according to the nature of the external excitation. The theory governing the operation of this class of vibration isolator is presented and their tunable filtering characteristics are demonstrated experimentally as functions of their design parameters. This concept can be employed in many applications to control the wave propagation and the force transmission of longitudinal vibrations both in the spectral and spatial domains in an attempt to stop/attenuate the propagation of undesirable disturbances.

  12. Novel Intriguing Strategies Attenuating to Sarcopenia

    Directory of Open Access Journals (Sweden)

    Kunihiro Sakuma

    2012-01-01

    Full Text Available Sarcopenia, the age-related loss of skeletal muscle mass, is characterized by a deterioration of muscle quantity and quality leading to a gradual slowing of movement, a decline in strength and power, increased risk of fall-related injury, and, often, frailty. Since sarcopenia is largely attributed to various molecular mediators affecting fiber size, mitochondrial homeostasis, and apoptosis, the mechanisms responsible for these deleterious changes present numerous therapeutic targets for drug discovery. Resistance training combined with amino acid-containing supplements is often utilized to prevent age-related muscle wasting and weakness. In this review, we summarize more recent therapeutic strategies (myostatin or proteasome inhibition, supplementation with eicosapentaenoic acid (EPA or ursolic acid, etc. for counteracting sarcopenia. Myostatin inhibitor is the most advanced research with a Phase I/II trial in muscular dystrophy but does not try the possibility for attenuating sarcopenia. EPA and ursolic acid seem to be effective as therapeutic agents, because they attenuate the degenerative symptoms of muscular dystrophy and cachexic muscle. The activation of peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α in skeletal muscle by exercise and/or unknown supplementation would be an intriguing approach to attenuating sarcopenia. In contrast, muscle loss with age may not be influenced positively by treatment with a proteasome inhibitor or antioxidant.

  13. In situ bioremediation (natural attenuation) at a gas plant waste site

    International Nuclear Information System (INIS)

    Ginn, J.S.; Sims, R.C.

    1995-01-01

    A former manufactured gas plant (MGP) waste site in New York was evaluated with regard to natural attenuation of polycyclic aromatic hydrocarbons (PAHs). Parent-compound concentrations of PAHs within an aquifer plume were observed to decrease with time subsequent to source removal of coal tar. Biotransformation-potential studies indicated that indigenous microorganisms in soil from the site were capable of degrading naphthalene and phenanthrene. A biochemical metabolite of phenanthrene degradation, 1-hydroxy-2-naphthoic acid (1H2NA), was tentatively characterized in coal-tar-contaminated soil from the site-based on liquid chromatographic retention time. Kinetic information was developed for the disappearance of phenanthrene and 1H2NA in nonspiked contaminated soil at the site. The Microtox trademark bioassay was used to evaluate toxicity trends in contaminated soil at the site. Results from the Microtox trademark indicated a decreasing trend in toxicity with respect to time in contaminated site soil. Research results were evaluated with regard to the National Research Council's guidelines for evaluating in situ bioremediation, and were used to enhance site characterization and monitoring information for evaluating the role of bioremediation as part of natural attenuation of PAHs at coal-tar-contaminated sites

  14. Toxicity of heavy metals in the environment

    National Research Council Canada - National Science Library

    Oehme, F.W

    1978-01-01

    ... as the fundamental mechanisms of toxicity resulting from heavy metal chemicals. The more common toxic heavy metals, along with their biochemistry and associated clinical syndromes, are then described...

  15. 2011 NATA - Air Toxics Monitors

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset includes annual (2005 - 2013) statistics of measured ambient air toxics concentrations (in micrograms per cubic meter) and associated risk estimates for...

  16. Borocaptate sodium (BSH) toxicity issues

    International Nuclear Information System (INIS)

    LaHann, T.

    1995-01-01

    ISU's Center for Toxicology Research has been conducting toxicity testing of borocaptate sodium (BSH) to aid in assessing if proposed human studies of BSH are likely to be acceptably safe. This report describes BSH interactions with other biological agents

  17. Acute toxicity of ingested fluoride.

    Science.gov (United States)

    Whitford, Gary Milton

    2011-01-01

    This chapter discusses the characteristics and treatment of acute fluoride toxicity as well as the most common sources of overexposure, the doses that cause acute toxicity, and factors that can influence the clinical outcome. Cases of serious systemic toxicity and fatalities due to acute exposures are now rare, but overexposures causing toxic signs and symptoms are not. The clinical course of systemic toxicity from ingested fluoride begins with gastric signs and symptoms, and can develop with alarming rapidity. Treatment involves minimizing absorption by administering a solution containing calcium, monitoring and managing plasma calcium and potassium concentrations, acid-base status, and supporting vital functions. Approximately 30,000 calls to US poison control centers concerning acute exposures in children are made each year, most of which involve temporary gastrointestinal effects, but others require medical treatment. The most common sources of acute overexposures today are dental products - particularly dentifrices because of their relatively high fluoride concentrations, pleasant flavors, and their presence in non-secure locations in most homes. For example, ingestion of only 1.8 ounces of a standard fluoridated dentifrice (900-1,100 mg/kg) by a 10-kg child delivers enough fluoride to reach the 'probably toxic dose' (5 mg/kg body weight). Factors that may influence the clinical course of an overexposure include the chemical compound (e.g. NaF, MFP, etc.), the age and acid-base status of the individual, and the elapsed time between exposure and the initiation of treatment. While fluoride has well-established beneficial dental effects and cases of serious toxicity are now rare, the potential for toxicity requires that fluoride-containing materials be handled and stored with the respect they deserve. Copyright © 2011 S. Karger AG, Basel.

  18. The Toxicity of Depleted Uranium

    OpenAIRE

    Briner, Wayne

    2010-01-01

    Depleted uranium (DU) is an emerging environmental pollutant that is introduced into the environment primarily by military activity. While depleted uranium is less radioactive than natural uranium, it still retains all the chemical toxicity associated with the original element. In large doses the kidney is the target organ for the acute chemical toxicity of this metal, producing potentially lethal tubular necrosis. In contrast, chronic low dose exposure to depleted uranium may not produce a c...

  19. L-ascorbate attenuates methamphetamine neurotoxicity through enhancing the induction of endogenous heme oxygenase-1.

    Science.gov (United States)

    Huang, Ya-Ni; Wang, Jiz-Yuh; Lee, Ching-Tien; Lin, Chih-Hung; Lai, Chien-Cheng; Wang, Jia-Yi

    2012-12-01

    Methamphetamine (METH) is a drug of abuse which causes neurotoxicity and increased risk of developing neurodegenerative diseases. We previously found that METH induces heme oxygenase (HO)-1 expression in neurons and glial cells, and this offers partial protection against METH toxicity. In this study, we investigated the effects of l-ascorbate (vitamin C, Vit. C) on METH toxicity and HO-1 expression in neuronal/glial cocultures. Cell viability and damage were evaluated by 3-(4,5-dimethylthianol-2-yl)-2,5 diphenyl tetrazolium bromide (MTT) reduction and lactate dehydrogenase (LDH) release, respectively. Neuronal and glial localization of HO-1 were identified by double immunofluorescence staining. Reactive oxygen species (ROS) production was measured using the fluorochrome 2',7'-dichlorofluorescin diacetate. HO-1 mRNA and protein expression were examined by RT-qPCR and Western blotting, respectively. Results show that Vit. C induced HO-1 mRNA and protein expressions in time- and concentration-dependent manners. Inhibition of p38 mitogen-activated protein kinase (MAPK) but not extracellular signal-regulated kinase (ERK) significantly blocked induction of HO-1 by Vit. C. HO-1 mRNA and protein expressions were significantly elevated by a combination of Vit. C and METH, compared to either Vit. C or METH alone. Pretreatment with Vit. C enhanced METH-induced HO-1 expression and attenuated METH-induced ROS production and neurotoxicity. Pharmacological inhibition of HO activity abolished suppressive effects of Vit. C on METH-induced ROS production and attenuated neurotoxicity. We conclude that induction of HO-1 expression contributes to the attenuation of METH-induced ROS production and neurotoxicity by Vit. C. We suggest that HO-1 induction by Vit. C may serve as a strategy to alleviate METH neurotoxicity. Copyright © 2012 Elsevier Inc. All rights reserved.

  20. Determination of the attenuation map in emission tomography

    CERN Document Server

    Zaidi, H

    2002-01-01

    Reliable attenuation correction methods for quantitative emission computed tomography (ECT) require accurate delineation of the body contour and often necessitate knowledge of internal anatomical structure. Two broad classes of methods have been used to calculate the attenuation map referred to as "transmissionless" and transmission-based attenuation correction techniques. While calculated attenuation correction belonging to the first class of methods is appropriate for brain studies, more adequate methods must be performed in clinical applications where the attenuation coefficient distribution is not known a priori, and for areas of inhomogeneous attenuation such as the chest. Measured attenuation correction overcomes this problem and utilizes different approaches to determine this map including transmission scanning, segmented magnetic resonance images or appropriately scaled X-ray CT scans acquired either independently on separate or simultaneously on multimodality imaging systems. Combination of data acqu...

  1. Determination of leachate toxicity through acute toxicity using Daphnia pulex and anaerobic toxicity assays

    OpenAIRE

    Carabalí-Rivera, Y. S; Barba-Ho, L. E; Torres-Lozada, P

    2017-01-01

    ABSTRACT The municipal solid waste (MSW) of large cities, in particular the ones of developing countries, is mainly disposed in landfills (LFs), whose inadequate management generates the emission of greenhouse gases and the production of leachates with high concentrations of organic and inorganic matter and, occasionally heavy metals. In this study, the toxicity of the leachates from an intermediate-age municipal landfill was evaluated by ecotoxicity and anaerobic toxicity tests. The acute to...

  2. Toxic stress and child refugees.

    Science.gov (United States)

    Murray, John S

    2018-01-01

    The purpose of this article was to describe the phenomenon of toxic stress and its impact on the physical and mental health of child refugees. Almost two decades ago, researchers found that recurring adverse childhood events (ACEs; e.g., physical, psychological, and sexual abuse, neglect, and household dysfunction such as substance abuse, mental illness, and criminal behavior) were associated with a significant increase in serious illnesses during adulthood. Illnesses include heart, lung, and liver disease, cancer, and bone fractures. The scientists reported that experiencing four or more ACEs during childhood significantly increases the risk for toxic stress. Toxic stress is defined as the exposure to extreme, frequent, and persistent adverse events without the presence of a supportive caretaker. There is a paucity of literature related to toxic stress and child refugees. However, it has been clearly established that the prolonged brutal and traumatizing war in Syria is having a profound impact on the physical and mental health of child refugees at a distressing rate. Prevention of toxic stress should be a primary goal of all pediatric healthcare professionals working with child refugees. While this seems daunting given the population, and the seemingly insurmountable stressors they experience, some basic interventions should be considered. Providing basic anticipatory guidance to parents and caregivers of child refugees, to encourage positive parenting and strengthening support networks, will be highly effective in developing the requisite buffers that mitigate the effects of stress and avoid toxic stress. Efforts should also be focused on addressing caregiver stress and improving their ability to provide safe, reliable, and nurturing care that will help to mitigate any stress response experienced by a child. It is critical that greater awareness be placed on the effects of toxic stress on child refugees who are exposed to significant adverse events early in life

  3. PPARα inhibition modulates multiple reprogrammed metabolic pathways in kidney cancer and attenuates tumor growth.

    Science.gov (United States)

    Abu Aboud, Omran; Donohoe, Dallas; Bultman, Scott; Fitch, Mark; Riiff, Tim; Hellerstein, Marc; Weiss, Robert H

    2015-06-01

    Kidney cancer [renal cell carcinoma (RCC)] is the sixth-most-common cancer in the United States, and its incidence is increasing. The current progression-free survival for patients with advanced RCC rarely extends beyond 1-2 yr due to the development of therapeutic resistance. We previously identified peroxisome proliferator-activating receptor-α (PPARα) as a potential therapeutic target for this disease and showed that a specific PPARα antagonist, GW6471, induced apoptosis and cell cycle arrest at G0/G1 in RCC cell lines associated with attenuation of cell cycle regulatory proteins. We now extend that work and show that PPARα inhibition attenuates components of RCC metabolic reprogramming, capitalizing on the Warburg effect. The specific PPARα inhibitor GW6471, as well as a siRNA specific to PPARα, attenuates the enhanced fatty acid oxidation and oxidative phosphorylation associated with glycolysis inhibition, and PPARα antagonism also blocks the enhanced glycolysis that has been observed in RCC cells; this effect did not occur in normal human kidney epithelial cells. Such cell type-specific inhibition of glycolysis corresponds with changes in protein levels of the oncogene c-Myc and has promising clinical implications. Furthermore, we show that treatment with GW6471 results in RCC tumor growth attenuation in a xenograft mouse model, with minimal obvious toxicity, a finding associated with the expected on-target effects on c-Myc. These studies demonstrate that several pivotal cancer-relevant metabolic pathways are inhibited by PPARα antagonism. Our data support the concept that targeting PPARα, with or without concurrent inhibition of glycolysis, is a potential novel and effective therapeutic approach for RCC that targets metabolic reprogramming in this tumor.

  4. Scatter and attenuation correction in SPECT

    International Nuclear Information System (INIS)

    Ljungberg, Michael

    2004-01-01

    The adsorbed dose is related to the activity uptake in the organ and its temporal distribution. Measured count rate with scintillation cameras is related to activity through the system sensitivity, cps/MBq. By accounting for physical processes and imaging limitations we can measure the activity at different time points. Correction for physical factor, such as attenuation and scatter is required for accurate quantitation. Both planar and SPECT imaging can be used to estimate activities for radiopharmaceutical dosimetry. Planar methods have been the most widely used but is a 2D technique. With accurate modelling for imagine in iterative reconstruction, SPECT methods will prove to be more accurate

  5. Attenuation correction using simultaneous emission - transmission tomography

    International Nuclear Information System (INIS)

    Ljubenov, V.; Marinkovic, P.

    1998-01-01

    In order to reduce degrading influence of attenuation on SPECT image quality, possibility for correction, based on simultaneous emission / transmission measurements, is discussed. Numerical photon transport simulations through the phantom and acquisition of of tomographic projections are performed by using Monte Carlo code MCNP-4A. Amount of contamination in transmission data due to photon Compton scattering for emission energy window is specially analyzed and appropriate spatial depending 'noise / signal' factors for three different external sources, applied with Tc-99m, are determined (author)

  6. Oxaliplatin-Related Ocular Toxicity

    Directory of Open Access Journals (Sweden)

    Marina Mesquida

    2010-11-01

    Full Text Available We report the case of a 52-year-old woman with advanced colorectal cancer who was treated with oxaliplatin on a FOLFOX schedule. After 3 cycles of chemotherapy, she started to complain of visual loss, altered color vision and neurological symptoms. Due to the suspicion of ocular and neurological toxicity, antineoplastic treatment was stopped. Her visual field showed a concentric bilateral scotoma and the electrooculogram test revealed severe impairment of the retinal pigment epithelium. Visual acuity, color vision and visual field recovered completely 8 months later, although electrooculogram remained abnormal. Ocular toxicity has been reported as an infrequent adverse event of oxaliplatin. Findings in this case indicate toxicity of this chemotherapeutic agent on the retinal pigment epithelium, which has not been reported before. This damage could be permanent, and it thus differs from previously described oxaliplatin-induced ocular toxicities, which are usually transient and reversible. With increasing use of oxaliplatin as first-line treatment in advanced colorectal cancer, we have to be aware of this possible toxicity.

  7. General aspects of metal toxicity.

    Science.gov (United States)

    Kozlowski, H; Kolkowska, P; Watly, J; Krzywoszynska, K; Potocki, S

    2014-01-01

    This review is focused on the general mechanisms of metal toxicity in humans. The possible and mainly confirmed mechanisms of their action are discussed. The metals are divided into four groups due to their toxic effects. First group comprises of metal ions acting as Fenton reaction catalyst mainly iron and copper. These types of metal ions participate in generation of the reactive oxygen species. Metals such as nickel, cadmium and chromium are considered as carcinogenic agents. Aluminum, lead and tin are involved in neurotoxicity. The representative of the last group is mercury, which may be considered as a generally toxic metal. Fenton reaction is a naturally occurring process producing most active oxygen species, hydroxyl radical: Fe(2+) + He2O2 ↔ Fe(3+) + OH(-) + OH(•) It is able to oxidize most of the biomolecules including DNA, proteins, lipids etc. The effect of toxicity depends on the damage of molecules i.e. production site of the hydroxyl radical. Chromium toxicity depends critically on its oxidation state. The most hazardous seems to be Cr(6+) (chromates) which are one of the strongest inorganic carcinogenic agents. Cr(6+) species act also as oxidative agents damaging among other nucleic acids. Redox inactive Al(3+), Cd(2+) or Hg(2+) may interfere with biology of other metal ions e.g. by occupying metal binding sites in biomolecules. All these aspects will be discussed in the review.

  8. Rosiglitazone attenuates pulmonary fibrosis and radiation-induced intestinal damage

    International Nuclear Information System (INIS)

    Mangoni, M.; Gerini, C.; Sottili, M.; Cassani, S.; Stefania, G.; Biti, G.; Castiglione, F.; Vanzi, E.; Bottoncetti, A.; Pupi, A.

    2011-01-01

    Full text of publication follows: Purpose.-The aim of the study was to evaluate radioprotective effect of rosiglitazone (RGZ) on a murine model of late pulmonary damage and of acute intestinal damage. Methods.- Lung fibrosis: C57 mice were treated with the radiomimetic agent bleomycin, with or without rosiglitazone (5 mg/kg/day). To obtain an independent qualitative and quantitative measure for lung fibrosis we used high resolution CT, performed twice a week during the entire observation period. Hounsfield Units (HU) of section slides from the upper and lower lung region were determined. On day 31 lungs were collected for histological analysis. Acute intestinal damage: mice underwent 12 Gy total body irradiation with or without rosiglitazone. Mice were sacrificed 24 or 72 h after total body irradiation and ileum and colon were collected. Results.- Lung fibrosis: after bleomycin treatment, mice showed typical CT features of lung fibrosis, including irregular septal thickening and patchy peripheral reticular abnormalities. Accordingly, HU lung density was dramatically increased. Rosiglitazone markedly attenuated the radiological signs of fibrosis and strongly inhibited HU lung density increase (60% inhibition at the end of the observation period). Histological analysis revealed that in bleomycin-treated mice, fibrosis involved 50-55% of pulmonary parenchyma and caused an alteration of the alveolar structures in 10% of parenchyma, while in rosiglitazone-treated mice, fibrosis involved only 20-25% of pulmonary parenchyma, without alterations of the alveolar structures. Acute intestinal damage: 24 h after 12 Gy of total body irradiation intestinal mucosa showed villi shortening, mucosal thickness and crypt necrotic changes. Rosiglitazone showed a histological improvement of tissue structure, with villi and crypts normalization and oedema reduction. Conclusion.- These results demonstrate that rosiglitazone displays a protective effect on pulmonary fibrosis and radiation

  9. THE ROLE FUNGI AND YEAST IN MONITORED NATURAL ATTENUATION

    Energy Technology Data Exchange (ETDEWEB)

    Brigmon, R.; Abe, M.; Johnson, B.; Simpson, W.; Mckinsey, P.

    2010-01-26

    Fungi and yeast have been characterized as important components in the bioremediation of organic contaminants in soil and water including polyaromatic hydrocarbons (PAHs); however, research into their ability to metabolize these compounds in extreme environments has been limited. In this work forty-three fungi and yeasts were isolated from a PAH-contaminated sludge waste lagoon in Poland. The lagoon was part of a monitored natural attenuation (MNA) study where natural reduction of PAHs and associated toxicity over time in non-disturbed areas of the sludge lagoon indicated MNA activity. The microorganisms were initially isolated on minimal medium containing naphthalene as the sole carbon and energy source. Fungal isolates were then maintained on MEA and identified based on microscopic examination and BIOLOG{reg_sign}. The analysis identified several of the fungal isolates as belonging to the genera Penicillium, Paecilomyces, Aspergillus, and Eupenicillium. Yeasts included Candida parapsilosis and C. fluvialitis. Further microbial characterization revealed that several isolates were capable of rowing on acidified media of pH 4, 3, and 2.5. Over twenty percent of the fungi demonstrated growth as low as pH 2.5. Of the 43 isolates examined, 24 isolates exhibited growth at 5 C. Nine of the fungal isolates exhibiting growth at 5 C were then examined for metabolic activity using a respirometer testing metabolic activity at pH 3. Microcosm studies confirmed the growth of the fungi on PAH contaminated sediment as the sole carbon and energy source with elevated metabolic rates indicating evidence of MNA. Our findings suggest that many of the Poland fungal isolates may be of value in the bioremediation processes in acidic waste sites in northern climates typical of Northern Europe.

  10. Natural attenuation potential of phenylarsenicals in anoxic groundwaters.

    Science.gov (United States)

    Hempel, Michael; Daus, Birgit; Vogt, Carsten; Weiss, Holger

    2009-09-15

    The extensive production of chemical warfare agents in the 20th century has led to serious contamination of soil and groundwater with phenyl arsenicals at former ammunition depots or warfare agent production sites worldwide. Most phenyl arsenicals are highly toxic for humans. The microbial degradation of phenylarsonic acid (PAA) and diphenylarsinic acid (DPAA) was investigated in microcosms made of anoxic groundwater/sediment mixtures taken from different depths of an anoxic, phenyl arsenical contaminated aquifer in Central Germany. DPAA was not transformed within 91 days incubation time in any of the microcosms. The removal of PAA can be described by a first order kinetics without a lag-phase (rate: 0.037 d(-1)). In sterilized microcosms, PAA concentrations always remained stable, demonstrating that PAA transformation was a biologically mediated process. PAA transformation occurred under sulfate-reducing conditions due to sulfate consumption and production of sulfide. The addition of lactate (1 mM), a typical substrate of sulfate-reducing bacteria, increased the transformation rate of PAA significantly up to 0.134 d(-1). The content of total arsenic was considerably reduced (> 75%). Intermediates of PAA transformation were detected by high performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS). Experiments with a pure strain and sterile controls of Desulfovibrio gigas spiked with PAA showed that the elimination process is linked to the presence of sulfide formed through bacterial activity. Phenyl arsenicals were likely immobilized in the sedimentthrough sulfur substitution and a subsequent sulfur bond under the prevailing sulfate reducing condition. The results of this study indicate that PAA can undergo microbiologically mediated transformation in anoxic aquifers, leading to reduced concentrations in groundwater, which indicate a (enhancend) natural attenuation potential.

  11. Necrosulfonamide Attenuates Spinal Cord Injury via Necroptosis Inhibition.

    Science.gov (United States)

    Wang, Yongxiang; Wang, Jingcheng; Wang, Hua; Feng, Xinmin; Tao, Yuping; Yang, Jiandong; Cai, Jun

    2018-03-31

    Spinal cord injury (SCI) is a serious trauma without efficient treatment currently. Necroptosis can be blocked post injury by special inhibitors. This study is to investigate the effects, mechanism, and potential benefit of necrosulfonamide (NSA) for SCI therapy. Pathologic condition was detected using hematoxylin-eosin staining on injured spinal cord and other major organs. Necroptosis-related factors-RIP1, RIP3, and MLKL-were detected using Western blot. Detections on mitochondrial functions such as adenosine triphosphate generation and activities of superoxide dismutase and caspase-3 were also performed. Finally, ethologic performance was detected using a 21-point open-field locomotion test. Reduced lesions and protected neurons were found in the injured spinal cord after treatment with NSA using hematoxylin-eosin staining for pathologic detection. No obvious toxicity on rat liver, kidney, heart, and spleen was detected. Rather than RIP1 and RIP3, MLKL was significantly inhibited by the NSA using Western blot detection. Adenosine triphosphate generation was obviously decreased post injury but slightly increased after the NSA treatment, especially 24 hours post injury. No significant changes were found on activities of superoxide dismutase and caspase-3 after the treatment of NSA. Ethologic performance was significantly improved using a 21-point, open-field locomotion test. Our research indicates NSA attenuates the spinal cord injury via necroptosis inhibition. It might be a potential and safe chemical benefit for SCI therapy. To our knowledge, this is the first study on the effects of NSA as treatment of traumatic SCI. Copyright © 2018 Elsevier Inc. All rights reserved.

  12. Rosiglitazone attenuates pulmonary fibrosis and radiation-induced intestinal damage

    Energy Technology Data Exchange (ETDEWEB)

    Mangoni, M.; Gerini, C.; Sottili, M.; Cassani, S.; Stefania, G.; Biti, G. [Radiotherapy Unit, Clinical Physiopathology Department, University of Florence, Firenze (Italy); Castiglione, F. [Department of Human Pathology and Oncology, University of Florence, Firenze (Italy); Vanzi, E.; Bottoncetti, A.; Pupi, A. [Nuclear Medicine Unit, Clinical Physiopathology Department, University of Florence, Firenze (Italy)

    2011-10-15

    Full text of publication follows: Purpose.-The aim of the study was to evaluate radioprotective effect of rosiglitazone (RGZ) on a murine model of late pulmonary damage and of acute intestinal damage. Methods.- Lung fibrosis: C57 mice were treated with the radiomimetic agent bleomycin, with or without rosiglitazone (5 mg/kg/day). To obtain an independent qualitative and quantitative measure for lung fibrosis we used high resolution CT, performed twice a week during the entire observation period. Hounsfield Units (HU) of section slides from the upper and lower lung region were determined. On day 31 lungs were collected for histological analysis. Acute intestinal damage: mice underwent 12 Gy total body irradiation with or without rosiglitazone. Mice were sacrificed 24 or 72 h after total body irradiation and ileum and colon were collected. Results.- Lung fibrosis: after bleomycin treatment, mice showed typical CT features of lung fibrosis, including irregular septal thickening and patchy peripheral reticular abnormalities. Accordingly, HU lung density was dramatically increased. Rosiglitazone markedly attenuated the radiological signs of fibrosis and strongly inhibited HU lung density increase (60% inhibition at the end of the observation period). Histological analysis revealed that in bleomycin-treated mice, fibrosis involved 50-55% of pulmonary parenchyma and caused an alteration of the alveolar structures in 10% of parenchyma, while in rosiglitazone-treated mice, fibrosis involved only 20-25% of pulmonary parenchyma, without alterations of the alveolar structures. Acute intestinal damage: 24 h after 12 Gy of total body irradiation intestinal mucosa showed villi shortening, mucosal thickness and crypt necrotic changes. Rosiglitazone showed a histological improvement of tissue structure, with villi and crypts normalization and oedema reduction. Conclusion.- These results demonstrate that rosiglitazone displays a protective effect on pulmonary fibrosis and radiation

  13. Gulf of Mexico mud toxicity limitations

    Energy Technology Data Exchange (ETDEWEB)

    Dunn, H.E.; Beardmore, D.H. (Phillips Petroleum Co., Bartlesville, OK (USA)); Stewart, W.S. (Drilling Specialties Co. (US))

    1989-10-01

    Because of the Environmental Protection Agency's recent toxicity limits on drilling mud discharges for offshore Gulf of Mexico, Phillips Petroleum conducted a mud toxicity study based on both field and lab tests. The study, discussed in this article, found the polyanionic cellulose-sulfomethylated quebracho-chrome lignosulfonate mud Phillips had been using would comfortably pass the toxicity limitations. The study also found barite and thinners were of low toxicity, and hydrocarbons and surfactants were highly toxic.

  14. Methotrexate-induced acute toxic leukoencephalopathy

    Directory of Open Access Journals (Sweden)

    Parag R Salkade

    2012-01-01

    Full Text Available Acute lymphoblastic leukemia (ALL is one of the most common malignancies of childhood, which is treated with high doses of methotrexate (MTX, as it crosses the blood-brain barrier and can be administered intravenously and via intrathecal route to eradicate leukemic cells from central nervous system (CNS. Additionally, high doses of MTX not only prevent CNS recurrence but also hematologic relapses. Although, standard treatment protocol for ALL includes multimodality therapy, MTX is usually associated with neurotoxicity and affects periventricular deep white matter region. Methotrexate-induced ′acute toxic leukoencephalopathy′ has varying clinical manifestations ranging from acute neurological deficit to seizures or encephalopathy. Diffusion weighted magnetic resonance imaging (DW-MRI is widely available and routinely used in clinical practice to identify acute stroke and also to distinguish acute stroke from non-stroke like conditions. We report a local teenage Chinese girl who developed 2 discrete episodes of left upper and lower limb weakness with left facial nerve paresis after receiving the 2 nd and 3 rd cycle of high dose of intravenous and intrathecal methotrexate, without having cranial irradiation. After each episode of her neurological deficit, the DW-MRI scan showed focal restricted diffusion in right centrum semiovale. Her left sided focal neurological deficit and facial nerve paresis almost completely subsided on both these occasions within 3 days of symptom onset. Follow-up DW-MRI, after her neurological recovery, revealed almost complete resolution of previously noted restricted diffusion in right centrum semiovale, while the lesion was not evident on concurrent T2W (T2-weighted and FLAIR (Fluid-Attenuated Inversion recovery sequences, nor showed any post contrast enhancement on post gadolinium enhanced T1W (T1-weighted sequences. No residual neurological deficit or intellectual impairment was identified on clinical follow up

  15. Wild lettuce (Lactuca virosa) toxicity.

    Science.gov (United States)

    Besharat, Sima; Besharat, Mahsa; Jabbari, Ali

    2009-01-01

    Wild lettuce (Lactuca virosa) can cause toxic effects when eaten. Wild lettuce grows in the north of Iran and some natives consume it unaware of its adverse side effects. We describe eight patients with manifestations of wild lettuce toxicity, admitted to a general hospital affiliated to the Golestan University of Medical Sciences. All the patients recovered (although one had to spend 48 h in the intensive care unit) and no chronic complications were reported. A clinical suspicion of toxicity caused by wild lettuce intake and an accurate history formed the basis of the diagnosis. Conservative treatment, vital sign monitoring, control of patient intake and output, and reducing patient agitation provided the basis for treatment.

  16. Methoxsalen-induced macular toxicity

    Directory of Open Access Journals (Sweden)

    Aditya Maitray

    2017-01-01

    Full Text Available Psoralen compounds such as methoxsalen are photosensitizer agents used in conjunction with ultraviolet A (UVA radiation exposure as photochemotherapy (Psoralens and ultraviolet-A therapy [PUVA therapy] for certain epidermal skin disorders such as psoriasis and vitiligo. Methoxsalen has been shown to be associated with premature cataract formation by forming adducts with lens proteins following oral administration and subsequent UVA exposure. Hence, the use of UV-filtering glasses is recommended during PUVA therapy sessions. Ocular tissues can be exposed to its photosensitizing effect with subsequent UV radiation exposure through sunlight if the patient was to be without protective eye glasses, potentially causing macular toxicity. Till date, there have been no reports in the literature of any posterior segment ocular toxicity arising from methoxsalen use. Here, we describe a case of a bilateral macular toxicity in a middle-aged male treated with methoxsalen for vitiligo.

  17. Aluminium Toxicity Targets in Plants

    Directory of Open Access Journals (Sweden)

    Sónia Silva

    2012-01-01

    Full Text Available Aluminium (Al is the third most abundant metallic element in soil but becomes available to plants only when the soil pH drops below 5.5. At those conditions, plants present several signals of Al toxicity. As reported by literature, major consequences of Al exposure are the decrease of plant production and the inhibition of root growth. The root growth inhibition may be directly/indirectly responsible for the loss of plant production. In this paper the most remarkable symptoms of Al toxicity in plants and the latest findings in this area are addressed. Root growth inhibition, ROS production, alterations on root cell wall and plasma membrane, nutrient unbalances, callose accumulation, and disturbance of cytoplasmic Ca2+ homeostasis, among other signals of Al toxicity are discussed, and, when possible, the behavior of Al-tolerant versus Al-sensitive genotypes under Al is compared.

  18. Methylmercury toxicity and functional programming.

    Science.gov (United States)

    Grandjean, Philippe

    2007-01-01

    Adverse health effects of developmental toxicants may induce abnormal functional programming that leads to lasting functional deficits. This notion is considered from epidemiological evidence using developmental methylmercury neurotoxicity as an example. Accumulating evidence indicates that adverse effects may occur even at low-level methylmercury exposures from seafood and freshwater fish. Neurobehavioral outcomes are usually non-specific, and imprecise exposure assessment results in a bias toward the null. Essential nutrients may promote the development of certain brain functions, thereby causing confounding bias. The functional deficits caused by prenatal methylmercury exposure appear to be permanent, and their extent may depend on the joint effect of toxicants and nutrients. The lasting functional changes caused by neurodevelopmental methylmercury toxicity fit into the pattern of functional programming, with effects opposite to those linked to beneficial stimuli.

  19. Vinpocetine attenuates lipid accumulation and atherosclerosis formation

    International Nuclear Information System (INIS)

    Cai, Yujun; Li, Jian-Dong; Yan, Chen

    2013-01-01

    Highlights: •Vinpocetine attenuates hyperlipidemia-induced atherosclerosis in a mouse model. •Vinpocetine antagonizes ox-LDL uptake and accumulation in macrophages. •Vinpocetine blocks the induction of ox-LDL receptor LOX-1 in vitro and in vivo. -- Abstract: Atherosclerosis, the major cause of myocardial infarction and stroke, is a chronic arterial disease characterized by lipid deposition and inflammation in the vessel wall. Cholesterol, in low-density lipoprotein (LDL), plays a critical role in the pathogenesis of atherosclerosis. Vinpocetine, a derivative of the alkaloid vincamine, has long been used as a cerebral blood flow enhancer for treating cognitive impairment. Recent study indicated that vinpocetine is a potent anti-inflammatory agent. However, its role in the pathogenesis of atherosclerosis remains unexplored. In the present study, we show that vinpocetine significantly reduced atherosclerotic lesion formation in ApoE knockout mice fed with a high-fat diet. In cultured murine macrophage RAW264.7 cells, vinpocetine markedly attenuated oxidized LDL (ox-LDL) uptake and foam cell formation. Moreover, vinpocetine greatly blocked the induction of ox-LDL receptor 1 (LOX-1) in cultured macrophages as well as in the LOX-1 level in atherosclerotic lesions. Taken together, our data reveal a novel role of vinpocetine in reduction of pathogenesis of atherosclerosis, at least partially through suppressing LOX-1 signaling pathway. Given the excellent safety profile of vinpocetine, this study suggests vinpocetine may be a therapeutic candidate for treating atherosclerosis

  20. Ultra-low acoustoelectric attenuation in graphene

    Science.gov (United States)

    Tang, Chiu-Chun; Chen, Yung-Fu; Ling, D. C.; Chi, C. C.; Chen, Jeng-Chung

    2017-03-01

    We investigate the acoustoelectric properties of graphene and extract its acoustoelectric attenuation Γ as a function of the carrier density n, tuned via ionic liquid gating. Acoustoelectric effects in graphene are induced by launching surface acoustic waves (SAWs) on a piezoelectric LiNbO3 substrate. We measure the acoustoelectric current Iae through graphene and extract the SAW attenuation factor Γ as a function of n. The magnitude of Iae increases with decreasing n when the n is far from the charge neutral point (CNP). When n is tuned across the CNP, Iae first exhibits a local maximum, vanishes at the CNP, and then changes sign in accordance with the associated change in the carrier polarity. By contrast, Γ monotonically increases with decreasing n and reaches a maximum at the CNP. The extracted values of Γ, calibrated at the central frequency of 189 MHz, vary from ˜0.4 m-1 to 6.8 m-1, much smaller than the values for known two-dimensional systems. Data analysis suggests that the evolution of Iae and Γ with n manifests the electronic states of graphene. Our experimental findings provide insightful information for developing innovative graphene-based devices.

  1. Boundary layer attenuation in turbulent sodium flows

    International Nuclear Information System (INIS)

    Tenchine, D.

    1994-01-01

    Temperature fluctuations are produced in the sodium coolant of Liquid Metal Reactors when flows at different temperatures are mixing. That occurs in various areas of the reactor plant, in the primary and the secondary circuits. This paper deals with secondary circuit pipings, specifically the Superphenix steam generator outlet. The possibility of thermal striping in this area is studied because of the mixing of a main 'hot' flow surrounded by a smaller 'cold' flow in the vertical pipe located below the steam generator. This work was developed in the frame of a collaboration between CEA, EDF and FRAMATOME. The purpose of our study is to measure temperature fluctuations in the fluid and on the structures, on a sodium reduced scale model of the outlet region of the steam generator. We want to evidence the boundary layer attenuation by comparing wall and fluid measurements. From these experimental data, we shall propose a methodology to predict the boundary layer attenuation and the temperature fluctuations at the surface of the structure, for pipe flow configurations

  2. Cranking model and attenuation of Coriolis interaction

    International Nuclear Information System (INIS)

    Lyutorovich, N.A.

    1987-01-01

    Description of rotational bands of odd deformed nuclei in the self-consistent Cranking model (SCM) is given. Causes of attenuation of the Coriolis interaction in the nuclei investigated are studied, and account of bound of one-particle degrees of freedom with rotation of the Hartree-Fock-Bogolyubov (HFB) self-consistent method is introduced additionally to SCM for qualitative agreement with experimental data. Merits and shortages of SCM in comparison with the quadruparticle-rotor (QR) model are discussed. All know ways for constructing the Hamiltonian QR model (or analog of such Hamiltonian) on the basis of the microscopic theory are shown to include two more approximations besides others: quasi-particle-rotational interaction leading to pair break is taken into account in the second order of the perturbation theory; some exchange diagrams are neglected among diagrams of the second order according to this interaction. If one makes the same approximations in SCM instead of HFB method, then the dependence of level energies on spin obtained in this case is turned out to be close to the results of the QR model. Besides, the problem on renormalization of matrix elements of quasi-rotational interaction occurs in such nonself-consistent approach as in the QR model. In so far as the similar problem does not occur in SCM, one can make the conclusion that the problem of attenuation of Coriolis interaction involves the approximations given above

  3. Electron attenuation in free, neutral ethane clusters.

    Science.gov (United States)

    Winkler, M; Myrseth, V; Harnes, J; Børve, K J

    2014-10-28

    The electron effective attenuation length (EAL) in free, neutral ethane clusters has been determined at 40 eV kinetic energy by combining carbon 1s x-ray photoelectron spectroscopy and theoretical lineshape modeling. More specifically, theory is employed to form model spectra on a grid in cluster size (N) and EAL (λ), allowing N and λ to be determined by optimizing the goodness-of-fit χ(2)(N, λ) between model and observed spectra. Experimentally, the clusters were produced in an adiabatic-expansion setup using helium as the driving gas, spanning a range of 100-600 molecules in mean cluster size. The effective attenuation length was determined to be 8.4 ± 1.9 Å, in good agreement with an independent estimate of 10 Å formed on the basis of molecular electron-scattering data and Monte Carlo simulations. The aggregation state of the clusters as well as the cluster temperature and its importance to the derived EAL value are discussed in some depth.

  4. Vinpocetine attenuates lipid accumulation and atherosclerosis formation

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Yujun [Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester, 601 Elmwood Ave, Rochester, NY 14642 (United States); Li, Jian-Dong [Center for Inflammation, Immunity and Infection, and Department of Biology, Georgia State University, Atlanta, GA 30303 (United States); Yan, Chen, E-mail: Chen_Yan@urmc.rochester.edu [Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester, 601 Elmwood Ave, Rochester, NY 14642 (United States)

    2013-05-10

    Highlights: •Vinpocetine attenuates hyperlipidemia-induced atherosclerosis in a mouse model. •Vinpocetine antagonizes ox-LDL uptake and accumulation in macrophages. •Vinpocetine blocks the induction of ox-LDL receptor LOX-1 in vitro and in vivo. -- Abstract: Atherosclerosis, the major cause of myocardial infarction and stroke, is a chronic arterial disease characterized by lipid deposition and inflammation in the vessel wall. Cholesterol, in low-density lipoprotein (LDL), plays a critical role in the pathogenesis of atherosclerosis. Vinpocetine, a derivative of the alkaloid vincamine, has long been used as a cerebral blood flow enhancer for treating cognitive impairment. Recent study indicated that vinpocetine is a potent anti-inflammatory agent. However, its role in the pathogenesis of atherosclerosis remains unexplored. In the present study, we show that vinpocetine significantly reduced atherosclerotic lesion formation in ApoE knockout mice fed with a high-fat diet. In cultured murine macrophage RAW264.7 cells, vinpocetine markedly attenuated oxidized LDL (ox-LDL) uptake and foam cell formation. Moreover, vinpocetine greatly blocked the induction of ox-LDL receptor 1 (LOX-1) in cultured macrophages as well as in the LOX-1 level in atherosclerotic lesions. Taken together, our data reveal a novel role of vinpocetine in reduction of pathogenesis of atherosclerosis, at least partially through suppressing LOX-1 signaling pathway. Given the excellent safety profile of vinpocetine, this study suggests vinpocetine may be a therapeutic candidate for treating atherosclerosis.

  5. Taurine zinc solid dispersions attenuate doxorubicin-induced hepatotoxicity and cardiotoxicity in rats.

    Science.gov (United States)

    Wang, Yu; Mei, Xueting; Yuan, Jingquan; Lu, Wenping; Li, Binglong; Xu, Donghui

    2015-11-15

    The clinical efficacy of anthracycline anti-neoplastic agents is limited by cardiac and hepatic toxicities. The aim of this study was to assess the hepatoprotective and cardioprotective effects of taurine zinc solid dispersions, which is a newly-synthesized taurine zinc compound, against doxorubicin-induced toxicity in Sprague-Dawley rats intraperitoneally injected with doxorubicin hydrochloride (3mg/kg) three times a week (seven injections) over 28 days. Hemodynamic parameters, levels of liver toxicity markers and oxidative stress were assessed. Taurine zinc significantly attenuated the reductions in blood pressure, left ventricular pressure and ± dp/dtmax, increases in serum alanine aminotransferase and aspartate aminotransferase activities, and reductions in serum Zn(2+) and albumin levels (Ptaurine zinc dose-dependently increased liver superoxide dismutase activity and glutathione concentration, and decreased malondialdehyde level (PTaurine zinc dose-dependently increased liver heme oxygenase-1 and UDP-glucuronyl transferase mRNA and protein expression (Ptaurine zinc inhibited c-Jun N-terminal kinase phosphorylation by upregulating dual-specificity phosphoprotein phosphatase-1. Additionally, taurine zinc inhibited cardiomyocyte apoptosis as there was decreased TUNEL/DAPI positivity and protein expression of caspase-3. These results indicate that taurine zinc solid dispersions prevent the side-effects of anthracycline-based anticancer therapy. The mechanisms might be associated with the enhancement of antioxidant defense system partly through activating transcription to synthesize endogenous phase II medicine enzymes and anti-apoptosis through inhibiting JNK phosphorylation. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Coenzyme Q10 and alpha-tocopherol protect against amitriptyline toxicity

    International Nuclear Information System (INIS)

    Cordero, Mario D.; Moreno-Fernandez, Ana Maria; Gomez-Skarmeta, Jose Luis; Miguel, Manuel de; Garrido-Maraver, Juan; Oropesa-Avila, Manuel; Rodriguez-Hernandez, Angeles; Navas, Placido; Sanchez-Alcazar, Jose Antonio

    2009-01-01

    Since amitriptyline is a very frequently prescribed antidepressant drug, it is not surprising that amitriptyline toxicity is relatively common. Amitriptyline toxic systemic effects include cardiovascular, autonomous nervous, and central nervous systems. To understand the mechanisms of amitriptyline toxicity we studied the cytotoxic effects of amitriptyline treatment on cultured primary human fibroblasts and zebrafish embryos, and the protective role of coenzyme Q 10 and alpha-tocopherol, two membrane antioxidants. We found that amitriptyline treatment induced oxidative stress and mitochondrial dysfunction in primary human fibroblasts. Mitochondrial dysfunction in amitriptyline treatment was characterized by reduced expression levels of mitochondrial proteins and coenzyme Q 10 , decreased NADH:cytochrome c reductase activity, and a drop in mitochondrial membrane potential. Moreover, and as a consequence of these toxic effects, amitriptyline treatment induced a significant increase in apoptotic cell death activating mitochondrial permeability transition. Coenzyme Q 10 and alpha-tocopherol supplementation attenuated ROS production, lipid peroxidation, mitochondrial dysfunction, and cell death, suggesting that oxidative stress affecting cell membrane components is involved in amitriptyline cytotoxicity. Furthermore, amitriptyline-dependent toxicity and antioxidant protection were also evaluated in zebrafish embryos, a well established vertebrate model to study developmental toxicity. Amitriptyline significantly increased embryonic cell death and apoptosis rate, and both antioxidants provided a significant protection against amitriptyline embryotoxicity

  7. Impacts of select organic ligands on the colloidal stability, dissolution dynamics, and toxicity of silver nanoparticles.

    Science.gov (United States)

    Pokhrel, Lok R; Dubey, Brajesh; Scheuerman, Phillip R

    2013-11-19

    Key understanding of potential transformations that may occur on silver nanoparticle (AgNP) surface upon interaction with naturally ubiquitous organic ligands (e.g., -SH (thoil), humic acid, or -COO (carboxylate)) is limited. Herein we investigated how dissolved organic carbon (DOC), -SH (in cysteine, a well-known Ag(+) chelating agent), and -COO (in trolox, a well-known antioxidant) could alter the colloidal stability, dissolution rate, and toxicity of citrate-functionalized AgNPs (citrate-AgNPs) against a keystone crustacean Daphnia magna. Cysteine, DOC, or trolox amendment of citrate-AgNPs differentially modified particle size, surface properties (charge, plasmonic spectra), and ion release dynamics, thereby attenuating (with cysteine or trolox) or promoting (with DOC) AgNP toxicity. Except with DOC amendment, the combined toxicity of AgNPs and released Ag under cysteine or trolox amendment was lower than of AgNO3 alone. The results of this study show that citrate-AgNP toxicity can be associated with oxidative stress, ion release, and the organism biology. Our evidence suggests that specific organic ligands available in the receiving waters can differentially surface modify AgNPs and alter their environmental persistence (changing dissolution dynamics) and subsequently the toxicity; hence, we caveat to generalize that surface modified nanoparticles upon environmental release may not be toxic to receptor organisms.

  8. DOPA Decarboxylase Modulates Tau Toxicity.

    Science.gov (United States)

    Kow, Rebecca L; Sikkema, Carl; Wheeler, Jeanna M; Wilkinson, Charles W; Kraemer, Brian C

    2018-03-01

    The microtubule-associated protein tau accumulates into toxic aggregates in multiple neurodegenerative diseases. We found previously that loss of D 2 -family dopamine receptors ameliorated tauopathy in multiple models including a Caenorhabditis elegans model of tauopathy. To better understand how loss of D 2 -family dopamine receptors can ameliorate tau toxicity, we screened a collection of C. elegans mutations in dopamine-related genes (n = 45) for changes in tau transgene-induced behavioral defects. These included many genes responsible for dopamine synthesis, metabolism, and signaling downstream of the D 2 receptors. We identified one dopamine synthesis gene, DOPA decarboxylase (DDC), as a suppressor of tau toxicity in tau transgenic worms. Loss of the C. elegans DDC gene, bas-1, ameliorated the behavioral deficits of tau transgenic worms, reduced phosphorylated and detergent-insoluble tau accumulation, and reduced tau-mediated neuron loss. Loss of function in other genes in the dopamine and serotonin synthesis pathways did not alter tau-induced toxicity; however, their function is required for the suppression of tau toxicity by bas-1. Additional loss of D 2 -family dopamine receptors did not synergize with bas-1 suppression of tauopathy phenotypes. Loss of the DDC bas-1 reduced tau-induced toxicity in a C. elegans model of tauopathy, while loss of no other dopamine or serotonin synthesis genes tested had this effect. Because loss of activity upstream of DDC could reduce suppression of tau by DDC, this suggests the possibility that loss of DDC suppresses tau via the combined accumulation of dopamine precursor levodopa and serotonin precursor 5-hydroxytryptophan. Published by Elsevier Inc.

  9. Silibinin attenuates sulfur mustard analog-induced skin injury by targeting multiple pathways connecting oxidative stress and inflammation.

    Directory of Open Access Journals (Sweden)

    Neera Tewari-Singh

    Full Text Available Chemical warfare agent sulfur mustard (HD inflicts delayed blistering and incapacitating skin injuries. To identify effective countermeasures against HD-induced skin injuries, efficacy studies were carried out employing HD analog 2-chloroethyl ethyl sulfide (CEES-induced injury biomarkers in skin cells and SKH-1 hairless mouse skin. The data demonstrate strong therapeutic efficacy of silibinin, a natural flavanone, in attenuating CEES-induced skin injury and oxidative stress. In skin cells, silibinin (10 µM treatment 30 min after 0.35/0.5 mM CEES exposure caused a significant (p90%, and activation of transcription factors NF-κB and AP-1 (complete reversal. Similarly, silibinin treatment was also effective in attenuating CEES-induced oxidative stress measured by 4-hydroxynonenal and 5,5-dimethyl-2-(8-octanoic acid-1-pyrolline N-oxide protein adduct formation, and 8-oxo-2-deoxyguanosine levels. Since our previous studies implicated oxidative stress, in part, in CEES-induced toxic responses, the reversal of CEES-induced oxidative stress and other toxic effects by silibinin in this study indicate its pleiotropic therapeutic efficacy. Together, these findings support further optimization of silibinin in HD skin toxicity model to develop a novel effective therapy for skin injuries by vesicants.

  10. Toxic clinical hypoxic radiation sensitizers plus radiation-induced toxicity

    International Nuclear Information System (INIS)

    Richmond, R.C.

    1984-01-01

    The operational definition espoused twelve years ago that clinical hypoxic radiation sensitizers should be nontoxic interferes with the recognition and research of useful radiation sensitizers. Eight years ago the toxic antitumor drug cis-dichlorodiammineplatinum(II) was reported to be a hypoxic radiation sensitizer and the selective antitumor action of this drug was stressed as potentially creating tumor-targeted radiation sensitization. This rationale of oxidative antitumor drugs as toxic and targeted clinical sensitizers is useful, and has led to the study reported here. The antitumor drug cis-(1,1-cyclobutane-dicarboxylato)diammineplatinum(II), or JM-8, is being tested in clinical trials. Cells of S. typhimurium in PBS in the presence of 0.2mM JM-8 are found to be sensitized to irradiation under hypoxic, but not oxic, conditions. JM-8 is nontoxic to bacteria at this concentration, but upon irradiation the JM-8 solution becomes highly toxic. This radiation induced toxicity of JM-8 preferentially develops from hypoxic solution, and thus contributes to the rationale of hypoxic tumor cell destruction

  11. Effect of long-term equilibration on the toxicity of molybdenum to soil organisms

    International Nuclear Information System (INIS)

    Gestel, Cornelis A.M. van; McGrath, Steve P.; Smolders, Erik; Diez Ortiz, Maria; Borgman, Eef; Verweij, Rudo A.; Buekers, Jurgen; Oorts, Koen

    2012-01-01

    To determine if long-term equilibration may alleviate molybdenum toxicity, earthworms, enchytraeids, collembolans and four plant species were exposed to three soils freshly spiked with Na 2 MoO 4 .2H 2 O and equilibrated for 6 or 11 months in the field with free drainage. Total Mo concentrations in soil decreased by leaching, most (up to 98%) in sandy soil and less (54–62%) in silty and clayey soils. Changes in residual Mo toxicity with time were inconclusive in sandy soil. In the other two soils, toxicity of residual total Mo was significantly reduced after 11 months equilibration with a median 5.5-fold increase in ED50s. Mo fixation in soil, i.e. the decrease of soil solution Mo concentrations at equivalent residual total soil Mo, was maximally a factor of 2.1 only. This experiment shows natural attenuation of molybdate ecotoxicity under field conditions is related to leaching of excess Mo and other ions as well as to slow ageing reactions. - Highlights: ► Three molybdate-spiked soils were equilibrated for 6 and 11 months outdoors. ► Mo chronic toxicity to earthworms, enchytraeids, Collembola and four plant species was assessed. ► Mo concentrations in all soils decreased due to leaching. ► Based on actual total Mo remaining in the soil, Mo toxicity decreased by a median factor of 5.5. ► Decreased Mo toxicity was due to leaching as well as slow ageing reactions. - Natural attenuation under field conditions is more related to leaching of excess molybdate than to slow ageing reactions

  12. CADDIS Volume 2. Sources, Stressors and Responses: Unspecified Toxic Chemicals

    Science.gov (United States)

    Intro to the unspecified toxic chemicals module, when to list toxic chemicals as a candidate cause, ways to measure toxic chemicals, simple and detailed conceptual diagrams for toxic chemicals, toxic chemicals module references and literature reviews.

  13. Unfocused beam patterns in nonattenuating and attenuating fluids

    International Nuclear Information System (INIS)

    Goldstein, Albert

    2004-01-01

    The most important aspect of an ultrasound measuring system is knowledge of the transducer beam pattern. At all depths accurate single integral equations have been derived for the full beam pattern of steady state unfocused circular flat piston sources radiating into nonattenuating and attenuating fluids. The axial depth of the beginning of the unattenuated beam pattern far field is found to be at 6.41Y 0 . The unattenuated single integral equations are identical to a Jinc function directivity term at this and deeper depths. For attenuating fluids values of α and z are found that permit the attenuated axial pressure to be represented by a plane wave multiplicative exponential attenuation factor. This knowledge will aid in the experimental design of highly accurate attenuation measurements. Accurate single integral equations for the attenuated full beam pattern are derived using complex Bessel functions

  14. An acoustic eikonal equation for attenuating VTI media

    KAUST Repository

    Hao, Qi

    2016-09-06

    We present an acoustic eikonal equation governing the complex-valued travel time of P-waves in attenuating, transversely isotropic media with a vertical symmetry axis (VTI). This equation is based on the assumption that the Pwave complex-valued travel time is independent of the Swave velocity parameter v in Thomsen\\'s notation and the attenuation coefficient A in the Thomsen-type notation for attenuating VTI media. We combine perturbation theory and Shanks transform to develop practical approximations to the attenuating acoustic eikonal equation, capable of admitting analytical description of the attenuation in homogeneous media. For a horizontal, attenuating VTI layer, we also derive non-hyperbolic approximations for the real and imaginary parts of the complex-valued reflection travel time.

  15. Determination of beta attenuation coefficients by means of timing method

    International Nuclear Information System (INIS)

    Ermis, E.E.; Celiktas, C.

    2012-01-01

    Highlights: ► Beta attenuation coefficients of absorber materials were found in this study. ► For this process, a new method (timing method) was suggested. ► The obtained beta attenuation coefficients were compatible with the results from the traditional one. ► The timing method can be used to determine beta attenuation coefficient. - Abstract: Using a counting system with plastic scintillation detector, beta linear and mass attenuation coefficients were determined for bakelite, Al, Fe and plexiglass absorbers by means of timing method. To show the accuracy and reliability of the obtained results through this method, the coefficients were also found via conventional energy method. Obtained beta attenuation coefficients from both methods were compared with each other and the literature values. Beta attenuation coefficients obtained through timing method were found to be compatible with the values obtained from conventional energy method and the literature.

  16. Characteristics of Earthquake Ground Motion Attenuation in Korea and Japan

    International Nuclear Information System (INIS)

    Choi, In-Kil; Choun, Young-Sun; Nakajima, Masato; Ohtori, Yasuki; Yun, Kwan-Hee

    2006-01-01

    The characteristics of a ground motion attenuation in Korea and Japan were estimated by using the earthquake ground motions recorded at the equal distance observation station by KMA, K-NET and KiK-net of Korea and Japan. The ground motion attenuation equations proposed for Korea and Japan were evaluated by comparing the predicted value for the Fukuoka earthquake with the observed records. The predicted values from the attenuation equations show a good agreement with the observed records and each other. It can be concluded from this study that the ground motion attenuation equations can be used for the prediction of strong ground motion attenuation and for an evaluation of the attenuation equations proposed for Korea

  17. Fuselage panel noise attenuation by piezoelectric switching control

    International Nuclear Information System (INIS)

    Makihara, Kanjuro; Onoda, Junjiro; Minesugi, Kenji; Miyakawa, Takeya

    2010-01-01

    This paper describes a problem that we encountered in our noise attenuation project and our solution for it. We intend to attenuate low-frequency noise that transmits through aircraft fuselage panels. Our method of noise attenuation is implemented with a piezoelectric semi-active system having a selective switch instead of an active energy-supply system. The semi-active controller is based on the predicted sound pressure distribution obtained from acoustic emission analysis. Experiments and numerical simulations demonstrate that the semi-active method attenuates acoustic levels of not only the simple monochromatic noise but also of broadband noise. We reveal that tuning the electrical parameters in the circuit is the key to effective noise attenuation, to overcome the acoustic excitation problem due to sharp switching actions, as well as to control chattering problems. The results obtained from this investigation provide meaningful insights into designing noise attenuation systems for comfortable aircraft cabin environments

  18. An attenuated projector-backprojector for iterative SPECT reconstruction

    International Nuclear Information System (INIS)

    Gullberg, G.T.; Pelc, N.J.; Huesman, R.H.; Budinger, T.F.; Malko, J.A.

    1985-01-01

    A new ray-driven projector-backprojector which can easily be adapted for hardware implementation is described and simulated in software. The projector-backprojector discretely models the attenuated Radon transform of a source distributed within an attenuating medium as line integrals of discrete pixels, obtained using the standard sampling technique of averaging the emission source or attenuation distribution over small square regions. Attenuation factors are calculated for each pixel during the projection and backprojection operations instead of using precalculated values. The calculation of the factors requires a specification of the attenuation distribution, estimated either from an assumed constant distribution and an approximate body outline or from transmission measurements. The distribution of attenuation coefficients is stored in memory for efficient access during the projection and backprojection operations. The reconstruction of the source distribution is obtained by using a conjugate gradient or SIRT type iterative algorithm which requires one projection and one backprojection operation for each iteration. (author)

  19. Bulk viscosity and ultrasonic attenuation in liquid metals

    International Nuclear Information System (INIS)

    Awasthi, O.N.; Murthy, B.V.S.

    1984-11-01

    Ultrasonic attenuation in simple liquid metals has been investigated using the thermodynamic theory of relaxation processes incorporating the concept of a two state model for the liquid near the melting point. Agreement of the results with the experimental values of the ultrasonic attenuation and bulk viscosity indicates that this might be an appropriate approach to explain the excess attenuation of ultrasonic waves in liquid metals. (author)

  20. UPLC/ESI-QTOF-MS-based metabolomics survey on the toxicity of triptolide and detoxication of licorice.

    Science.gov (United States)

    Wang, Zhuo; Liu, Jian-Qun; Xu, Jin-Di; Zhu, He; Kong, Ming; Zhang, Guo-Hua; Duan, Su-Min; Li, Xiu-Yang; Li, Guang-Fu; Liu, Li-Fang; Li, Song-Lin

    2017-06-01

    Triptolide (TP) from Tripterygium wilfordii has been demonstrated to possess anti-inflammatory, immunosuppressive, and anticancer activities. TP is specially used for the treatment of awkward rheumatoid arthritis, but its clinical application is confined by intense side effects. It is reported that licorice can obviously reduce the toxicity of TP, but the detailed mechanisms involved have not been comprehensively investigated. The current study aimed to explore metabolomics characteristics of the toxic reaction induced by TP and the intervention effect of licorice water extraction (LWE) against such toxicity. Obtained urine samples from control, TP and TP + LWE treated rats were analyzed by UPLC/ESI-QTOF-MS. The metabolic profiles of the control and the TP group were well differentiated by the principal component analysis and orthogonal partial least squares-discriminant analysis. The toxicity of TP was demonstrated to be evolving along with the exposure time of TP. Eight potential biomarkers related to TP toxicity were successfully identified in urine samples. Furthermore, LWE treatment could attenuate the change in six of the eight identified biomarkers. Functional pathway analysis revealed that the alterations in these metabolites were associated with tryptophan, pantothenic acid, and porphyrin metabolism. Therefore, it was concluded that LWE demonstrated interventional effects on TP toxicity through regulation of tryptophan, pantothenic acid, and porphyrin metabolism pathways, which provided novel insights into the possible mechanisms of TP toxicity as well as the potential therapeutic effects of LWE against such toxicity. Copyright © 2017 China Pharmaceutical University. Published by Elsevier B.V. All rights reserved.

  1. Total Reducing Capacity in Aquifer Minerals and Sediments: Quantifying the Potential to Attenuate Cr(VI) in Groundwater

    International Nuclear Information System (INIS)

    Sisman, S. Lara

    2015-01-01

    Hexavalent chromium, Cr(VI), is present in the environment as a byproduct of industrial processes. Due to its mobility and toxicity, it is crucial to attenuate or remove Cr(VI) from the environment. The objective of this investigation was to quantify potential natural attenuation, or reduction capacity, of reactive minerals and aquifer sediments. Samples of reduced-iron containing minerals such as ilmenite, as well as Puye Formation sediments representing a contaminated aquifer in New Mexico, were reacted with chromate. The change in Cr(VI) during the reaction was used to calculate reduction capacity. This study found that minerals that contain reduced iron, such as ilmenite, have high reducing capacities. The data indicated that sample history may impact reduction capacity tests due to surface passivation. Further, this investigation identified areas for future research including: a) refining the relationships between iron content, magnetic susceptibility and reduction capacity, and b) long term kinetic testing using fresh aquifer sediments.

  2. Total Reducing Capacity in Aquifer Minerals and Sediments: Quantifying the Potential to Attenuate Cr(VI) in Groundwater

    Energy Technology Data Exchange (ETDEWEB)

    Sisman, S. Lara [Univ. of Virginia, Charlottesville, VA (United States); Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-07-20

    Hexavalent chromium, Cr(VI), is present in the environment as a byproduct of industrial processes. Due to its mobility and toxicity, it is crucial to attenuate or remove Cr(VI) from the environment. The objective of this investigation was to quantify potential natural attenuation, or reduction capacity, of reactive minerals and aquifer sediments. Samples of reduced-iron containing minerals such as ilmenite, as well as Puye Formation sediments representing a contaminated aquifer in New Mexico, were reacted with chromate. The change in Cr(VI) during the reaction was used to calculate reduction capacity. This study found that minerals that contain reduced iron, such as ilmenite, have high reducing capacities. The data indicated that sample history may impact reduction capacity tests due to surface passivation. Further, this investigation identified areas for future research including: a) refining the relationships between iron content, magnetic susceptibility and reduction capacity, and b) long term kinetic testing using fresh aquifer sediments.

  3. Self-attenuation factors in gamma-ray spectrometry

    International Nuclear Information System (INIS)

    Korun, M.

    1999-01-01

    The relation between the self-attenuation factors and the distribution function describing the number of photons detected in the full-energy peaks, as a function of their path length in the sample is presented. The relations between the self-attenuation factor and the moments of the distribution function, the average path length and the variance are also presented. The use of these relations is illustrated by applying them to self-attenuation factors describing attenuation in cylindrical samples. The results of the calculations are compared with the measured average path lengths and discussed in terms of the properties of the distribution function. (author)

  4. Compensation for nonuniform attenuation in SPECT brain imaging

    International Nuclear Information System (INIS)

    Glick, S.J.; King, M.A.; Pan, T.S.; Soares, E.J.

    1996-01-01

    Accurate compensation for photon attenuation is needed to perform quantitative brain single-photon-emission computed tomographic (SPECT) imaging. Bellini's attenuation-compensation method has been used with a nonuniform attenuation map to account for the nonuniform attenuation properties of the head. Simulation studies using a three-dimensional (3-D) digitized anthropomorphic brain phantom were conducted to compare quantitative accuracy of reconstructions obtained with the nonuniform Bellini method to that obtained with the Chang method and to iterative reconstruction using maximum-likelihood expectation maximization (ML-EM). Using the Chang method and assuming the head to be a uniform attenuator gave reconstructions with an average bias of approximately 6-8%, whereas using the Bellini or the iterative ML-EM method with a nonuniform attenuation map gave an average bias of approximately 1%. The computation time required to implement nonuniform attenuation compensation with the Bellini algorithm is approximately equivalent to the time required to perform one iteration of ML-EM. Thus, using the Bellini method with a nonuniform attenuation map provides accurate compensation for photon attenuation within the head, and the method can be implemented in computation times suitable for routine clinical use

  5. An Approximate Method for the Acoustic Attenuating VTI Eikonal Equation

    KAUST Repository

    Hao, Q.

    2017-05-26

    We present an approximate method to solve the acoustic eikonal equation for attenuating transversely isotropic media with a vertical symmetry axis (VTI). A perturbation method is used to derive the perturbation formula for complex-valued traveltimes. The application of Shanks transform further enhances the accuracy of approximation. We derive both analytical and numerical solutions to the acoustic eikonal equation. The analytic solution is valid for homogeneous VTI media with moderate anellipticity and strong attenuation and attenuation-anisotropy. The numerical solution is applicable for inhomogeneous attenuating VTI media.

  6. An Approximate Method for the Acoustic Attenuating VTI Eikonal Equation

    KAUST Repository

    Hao, Q.; Alkhalifah, Tariq Ali

    2017-01-01

    We present an approximate method to solve the acoustic eikonal equation for attenuating transversely isotropic media with a vertical symmetry axis (VTI). A perturbation method is used to derive the perturbation formula for complex-valued traveltimes. The application of Shanks transform further enhances the accuracy of approximation. We derive both analytical and numerical solutions to the acoustic eikonal equation. The analytic solution is valid for homogeneous VTI media with moderate anellipticity and strong attenuation and attenuation-anisotropy. The numerical solution is applicable for inhomogeneous attenuating VTI media.

  7. Attenuation of multiples in image space

    Science.gov (United States)

    Alvarez, Gabriel F.

    In complex subsurface areas, attenuation of 3D specular and diffracted multiples in data space is difficult and inaccurate. In those areas, image space is an attractive alternative. There are several reasons: (1) migration increases the signal-to-noise ratio of the data; (2) primaries are mapped to coherent events in Subsurface Offset Domain Common Image Gathers (SODCIGs) or Angle Domain Common Image Gathers (ADCIGs); (3) image space is regular and smaller; (4) attenuating the multiples in data space leaves holes in the frequency-Wavenumber space that generate artifacts after migration. I develop a new equation for the residual moveout of specular multiples in ADCIGs and use it for the kernel of an apex-shifted Radon transform to focus and separate the primaries from specular and diffracted multiples. Because of small amplitude, phase and kinematic errors in the multiple estimate, we need adaptive matching and subtraction to estimate the primaries. I pose this problem as an iterative least-squares inversion that simultaneously matches the estimates of primaries and multiples to the data. Standard methods match only the estimate of the multiples. I demonstrate with real and synthetic data that the method produces primaries and multiples with little cross-talk. In 3D, the multiples exhibit residual moveout in SODCIGs in in-line and cross-line offsets. They map away from zero subsurface offsets when migrated with the faster velocity of the primaries. In ADCIGs the residual moveout of the primaries as a function of the aperture angle, for a given azimuth, is flat for those angles that illuminate the reflector. The multiples have residual moveout towards increasing depth for increasing aperture angles at all azimuths. As a function of azimuth, the primaries have better azimuth resolution than the multiples at larger aperture angles. I show, with a real 3D dataset, that even below salt, where illumination is poor, the multiples are well attenuated in ADCIGs with the new

  8. Enhanced Attenuation Technologies: Passive Soil Vapor Extraction

    Energy Technology Data Exchange (ETDEWEB)

    Vangelas, K.; Looney, B.; Kamath, R.; Adamson, D.; Newell, C.

    2010-03-15

    Passive soil vapor extraction (PSVE) is an enhanced attenuation (EA) approach that removes volatile contaminants from soil. The extraction is driven by natural pressure gradients between the subsurface and atmosphere (Barometric Pumping), or by renewable sources of energy such as wind or solar power (Assisted PSVE). The technology is applicable for remediating sites with low levels of contamination and for transitioning sites from active source technologies such as active soil vapor extraction (ASVE) to natural attenuation. PSVE systems are simple to design and operate and are more cost effective than active systems in many scenarios. Thus, PSVE is often appropriate as an interim-remedial or polishing strategy. Over the past decade, PSVE has been demonstrated in the U.S. and in Europe. These demonstrations provide practical information to assist in selecting, designing and implementing the technology. These demonstrations indicate that the technology can be effective in achieving remedial objectives in a timely fashion. The keys to success include: (1) Application at sites where the residual source quantities, and associated fluxes to groundwater, are relatively low; (2) Selection of the appropriate passive energy source - barometric pumping in cases with a deep vadose zone and barrier (e.g., clay) layers that separate the subsurface from the atmosphere and renewable energy assisted PSVE in other settings and where higher flow rates are required. (3) Provision of sufficient access to the contaminated vadose zones through the spacing and number of extraction wells. This PSVE technology report provides a summary of the relevant technical background, real-world case study performance, key design and cost considerations, and a scenario-based cost evaluation. The key design and cost considerations are organized into a flowchart that dovetails with the Enhanced Attenuation: Chlorinated Organics Guidance of the Interstate Technology and Regulatory Council (ITRC). The PSVE

  9. Baltimore Air Toxics Study (BATS)

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, D.A. [Sullivan Environmental Consulting, Inc., Alexandria, VA (United States)

    1996-12-31

    The Baltimore Air Toxics Study is one of the three urban air toxics initiatives funded by EPA to support the development of the national air toxics strategy. As part of this project, the Air Quality Integrated Management System (AIMS) is under development. AIMS is designed to bring together the key components of urban air quality management into an integrated system, including emissions assessment, air quality modeling, and air quality monitoring. Urban area source emissions are computed for a wide range of pollutants and source categories, and are joined with existing point source emissions data. Measured air quality data are used to evaluate the adequacy of the emissions data and model treatments as a function of season, meteorological parameters, and daytime/nighttime conditions. Based on tested model performance, AIMS provides the potential to improve the ability to predict air quality benefits of alternative control options for criteria and toxic air pollutants. This paper describes the methods used to develop AIMS, and provides examples from its application in the Baltimore metropolitan area. The use of AIMS in the future to enhance environmental management of major industrial facilities also will be addressed in the paper.

  10. Gossypol Toxicity from Cottonseed Products

    Directory of Open Access Journals (Sweden)

    Ivana Cristina N. Gadelha

    2014-01-01

    Full Text Available Gossypol is a phenolic compound produced by pigment glands in cotton stems, leaves, seeds, and flower buds (Gossypium spp.. Cottonseed meal is a by-product of cotton that is used for animal feeding because it is rich in oil and proteins. However, gossypol toxicity limits cottonseed use in animal feed. High concentrations of free gossypol may be responsible for acute clinical signs of gossypol poisoning which include respiratory distress, impaired body weight gain, anorexia, weakness, apathy, and death after several days. However, the most common toxic effects is the impairment of male and female reproduction. Another important toxic effect of gossypol is its interference with immune function, reducing an animal’s resistance to infections and impairing the efficiency of vaccines. Preventive procedures to limit gossypol toxicity involve treatment of the cottonseed product to reduce the concentration of free gossypol with the most common treatment being exposure to heat. However, free gossypol can be released from the bound form during digestion. Agronomic selection has produced cotton varieties devoid of glands producing gossypol, but these varieties are not normally grown because they are less productive and are more vulnerable to attacks by insects.

  11. Oxidative stress in chemical toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Kappus, H.

    1986-05-01

    The toxic effect of compounds which undergo redox cycling enzymatic one-electron reduction are reviewed. First of all, the enzymatic reduction of these compounds leads to reactive intermediates, mainly radicals which react with oxygen, whereby superoxide anion radicals are formed. Further oxygen metabolites are hydrogen peroxide, singlet oxygen and hydroxyl radicals. The role of these oxygen metabolites in toxicity is discussed. The occurrence of lipid peroxidation during redox cycling of quinonoide compounds, e.g., adriamycin, and the possible relationship to their toxicity is critically evaluated. It is shown that iron ions play a crucial role in lipid peroxidation induced by redox cycling compounds. DNA damage by metal chelates, e.g., bleomycin, is discussed on the basis of findings that enzymatic redox cycling of a bleomycin-iron complex has been observed. The involvement of hydroxyl radicals in bleomycin-induced DNA damage occurring during redox cycling in cell nuclei is claimed. Redox cycling of other substances, e.g., aromatic amines, is discussed in relation to carcinogenesis. Other chemical groups, e.g., nitroaromatic compounds, hydroxylamines and azo compounds are included. Other targets for oxygen radical attack, e.g., proteins, are also dealt with. It is concluded that oxygen radical formation by redox cycling may be a critical event in toxic effects of several compounds if the protective mechanisms of cells are overwhelmed.

  12. Holiday Plants with Toxic Misconceptions

    Directory of Open Access Journals (Sweden)

    Zabrina N. Evens

    2012-12-01

    Full Text Available Several plants are used for their decorative effect during winter holidays. This review explores the toxic reputation and proposed management for exposures to several of those, namely poinsettia (Euphorbia pulcherrima, English holly (Ilex aquifolium, American holly (Ilex opaca,bittersweet (Solanum dulcamara, Jerusalem cherry (Solanum pseudocapsicum, Americanmistletoe (Phoradendron serotinum, and European mistletoe (Viscum album.

  13. REPRODUCTIVE TOXICITY OF PHTHALATE ESTERS

    Science.gov (United States)

    Phthalate esters display several modes of toxicity in mammalian species. In the rat, in utero exposure at relatively low dosage levels disrupts development of the reproductive system of the male rat by altering fetal testis hormone production. This presentation is a review of t...

  14. Attenuation and Dispersion in Earth's Materials

    Science.gov (United States)

    Gueguen, Y.

    2012-04-01

    One of the last challenges of Pr. Luigi Burlini has been to set up an experimental apparatus that would measure elastic wave attenuation under high pressure conditions. This project has since been developed by his colleagues and students at ETH. As a tribute to Luigi Burlini, this presentation aims at recalling why such measurements are important , how challenging such a project is, and what the main issues ahead are. Most of our knowledge about either crustal layers (seismic exploration) or deeper layers (seismology) results from data related to elastic wave propagation inside the Earth. The large amount of available data as well as the huge capability of computers are such that descriptions in terms of isotropic homogeneous layers appear to be very crude today. Anisotropic, heterogeneous models are reported at various scales. In addition, accounting for wave attenuation (the Q factor) is potentially of great interest. The Q factor is highly sensitive to processes that involve some departure from perfect elasticity. Its knowledge may provide information on possible fluid content, temperature, etc. This is because various processes may dissipate energy (and thus lower Q value) as a result of fluid flow, solid flow, etc., depending on the precise P-T conditions at depth. This points immediately to the theoretical challenge of Q investigations: there are many possible ways for a rock to not behave as a perfect elastic body. To model these various mechanisms and identify in which conditions they can take place is a first major challenge. The second challenge is on the experimental ground. What is looked for is to get low frequencies (f close to seismic frequencies) Q data on crustal (or mantle) rocks at high pressure P-high temperature T. Experiments in such highT-high P-low f conditions are extremely difficult to perform. Only in Canberra (I. Jackson) and now in Zurich such conditions have been achieved. Attenuation and dispersion (frequency dependence) of elastic

  15. Factors influencing radon attenuation by tailing covers

    International Nuclear Information System (INIS)

    Silker, W.B.; Rogers, V.C.

    1981-07-01

    The US NRC, in its Generic Environmental Impact Statement on uranium milling has specified that the radon flux escaping a uranium mill tailings pile will be reduced to pCi/m 2 s by application of covering layers of soils and clays. These covers present a radon diffusion barrier, which sufficiently increases the time required for radon passage from the tailings to the atmosphere to allow for decay of 222 Rn within the cover. The depth of cover necessary to reduce the escaping radon flux to the prescribed level is to be determined by calculation, and requires precise knowledge of the radon diffusion coefficient in the covering media. A Radon Attenuation Test Facility was developed to determine rates of radon diffusion through candidate cover materials. This paper describes this facility and its application for determining the influence of physical properties of the soil column on the radon diffusion coefficient

  16. Attenuation of thermal neutron through graphite

    International Nuclear Information System (INIS)

    Adib, M.; Ismaail, H.; Fathaallah, M.; Abbas, Y.; Habib, N.; Wahba, M.

    2004-01-01

    Calculation of the nuclear capture, thermal diffuse and Bragg scattering cross-sections as a function of graphite temperature and crystalline from for neutron energies from 1 me V< E<10 eV were carried out. Computer programs have been developed which allow calculation for the graphite hexagonal closed-pack structure in its polycrystalline form and pyrolytic one. I The calculated total cross-section for polycrystalline graphite were compared with the experimental values. An overall agreement is indicated between the calculated values and experimental ones. Agreement was also obtained for neutron cross-section measured for oriented pyrolytic graphite at room and liquid nitrogen temperatures. A feasibility study for use of graphite in powdered form as a cold neutron filter is details. The calculated attenuation of thermal neutrons through large mosaic pyrolytic graphite show that such crystals can be used effectively as second order filter of thermal neutron beams and that cooling improve their effectiveness

  17. Release and attenuation of fluorocarbons in landfills

    DEFF Research Database (Denmark)

    Kjeldsen, Peter; Scheutz, Charlotte

    2003-01-01

    Several halocarbons with very high global warming and ozone depleting potentials have been used as blowing agent for insulation foam in refrigerators and freezers. Many appliances are shredded after the end of their useful life. Release experiments carried out in the laboratory on insulation foam...... blown with CFC-11, HCFC-141b, HFC- 134a, and HFC-245fa revealed that most of the blowing agent is not released to the atmosphere during a six-week period following the shredding process. The fraction which is released in the six-week period is highly dependent on how fine the foam is shredded....... The residual blowing agent remaining after the six-week period may be very slowly released if the integrity of the foam particles with respect to diffusional properties is kept after disposal of the foam waste in landfills. Laboratory experiments simulating attenuation processes in the landfilled waste...

  18. Core disgust is attenuated by ingroup relations.

    Science.gov (United States)

    Reicher, Stephen D; Templeton, Anne; Neville, Fergus; Ferrari, Lucienne; Drury, John

    2016-03-08

    We present the first experimental evidence to our knowledge that ingroup relations attenuate core disgust and that this helps explain the ability of groups to coact. In study 1, 45 student participants smelled a sweaty t-shirt bearing the logo of another university, with either their student identity (ingroup condition), their specific university identity (outgroup condition), or their personal identity (interpersonal condition) made salient. Self-reported disgust was lower in the ingroup condition than in the other conditions, and disgust mediated the relationship between condition and willingness to interact with target. In study 2, 90 student participants smelled a sweaty target t-shirt bearing either the logo of their own university, another university, or no logo, with either their student identity or their specific university identity made salient. Walking time to wash hands and pumps of soap indicated that disgust was lower where the relationship between participant and target was ingroup rather than outgroup or ambivalent (no logo).

  19. Attenuation of species abundance distributions by sampling

    Science.gov (United States)

    Shimadzu, Hideyasu; Darnell, Ross

    2015-01-01

    Quantifying biodiversity aspects such as species presence/ absence, richness and abundance is an important challenge to answer scientific and resource management questions. In practice, biodiversity can only be assessed from biological material taken by surveys, a difficult task given limited time and resources. A type of random sampling, or often called sub-sampling, is a commonly used technique to reduce the amount of time and effort for investigating large quantities of biological samples. However, it is not immediately clear how (sub-)sampling affects the estimate of biodiversity aspects from a quantitative perspective. This paper specifies the effect of (sub-)sampling as attenuation of the species abundance distribution (SAD), and articulates how the sampling bias is induced to the SAD by random sampling. The framework presented also reveals some confusion in previous theoretical studies. PMID:26064626

  20. LIVE ATTENUATED VACCINES FOR THE IMMUNOPROPHYLAXIS

    Directory of Open Access Journals (Sweden)

    O. A. Shamsutdinova

    2017-01-01

    Full Text Available The review focuses on the history of the production of live antiviral vaccines and their use for the prevention of infectious diseases. It was noted that before the beginning of the 20th century, only three live vaccines were developed and put into practice — against smallpox, rabies, plague. The discovery of D. Enders, T.H. Weller and F.Ch. Robins of the ability of the polio virus, and then of a number of other viruses, to reproduce in vitro in cell cultures of various types, greatly expanded the studies on the production of attenuated strains of viruses for live vaccines. The historical stages of obtaining and introducing live vaccines for the prevention of smallpox, poliomyelitis, measles, rubella, and mumps are highlighted. Arguments in favor of the use of associated vaccine preparations for the prevention of viral infections are presented. Various variants of the strategy and tactics of using live vaccines, which are used for specific prevention of viral infections in different countries, are described. The review provides information on technological methods for obtaining antiviral vaccines. The publications testifying to the development of specific reactions in immunized vaccine strains of measles, mumps, poliomyelitis and rubella viruses, such as aseptic meningitis (vaccine strains of mumps virus, acute arthritis (vaccine rubella virus strains, temperature reactions, rash (vaccine strains of the virus Measles, vaccine-associated paralytic poliomyelitis (VAPP vaccine vaccine poliovirus. It is particularly noted that the long experience of vaccine prevention both in Russia and abroad convincingly shows that the risk of developing post-vaccination complications is incommensurably lower than the risk of causing harm to health from the corresponding infections. It is concluded that despite introduction of new third and fourth generation vaccines into practice, live attenuated vaccines do not lose their significance and are used in vaccine

  1. A miniaturized reconfigurable broadband attenuator based on RF MEMS switches

    International Nuclear Information System (INIS)

    Guo, Xin; Gong, Zhuhao; Zhong, Qi; Liang, Xiaotong; Liu, Zewen

    2016-01-01

    Reconfigurable attenuators are widely used in microwave measurement instruments. Development of miniaturized attenuation devices with high precision and broadband performance is required for state-of-the-art applications. In this paper, a compact 3-bit microwave attenuator based on radio frequency micro-electro-mechanical system (RF MEMS) switches and polysilicon attenuation modules is presented. The device comprises 12 ohmic contact MEMS switches, π -type polysilicon resistive attenuation modules and microwave compensate structures. Special attention was paid to the design of the resistive network, compensate structures and system simulation. The device was fabricated using micromachining processes compatible with traditional integrated circuit fabrication processes. The reconfigurable attenuator integrated with RF MEMS switches and resistive attenuation modules was successfully fabricated with dimensions of 2.45  ×  4.34  ×  0.5 mm 3 , which is 1/1000th of the size of a conventional step attenuator. The measured RF performance revealed that the attenuator provides 10–70 dB attenuation at 10 dB intervals from 0.1–20 GHz with an accuracy better than  ±1.88 dB at 60 dB and an error of less than 2.22 dB at 10 dB. The return loss of each state of the 3-bit attenuator was better than 11.95 dB (VSWR  <  1.71) over the entire operating band. (paper)

  2. Antiulcerogenic Activity and Toxicity of Bauhinia holophylla Hydroalcoholic Extract

    Science.gov (United States)

    Rozza, A. L.; Cesar, D. A. S.; Pieroni, L. G.; Saldanha, L. L.; Dokkedal, A. L.; De-Faria, F. M.; Souza-Brito, A. R. M.; Vilegas, W.; Takahira, R. K.; Pellizzon, C. H.

    2015-01-01

    Several species of Bauhinia are used in traditional medicine for the treatment of gastrointestinal diseases, diabetes, and inflammation, among other conditions. The aim of this study was to investigate the antiulcer effect of a hydroalcoholic extract from the leaves of B. holophylla. The chemical profile of the extract was determined by HPLC-PAD-ESI-IT-MS. A dose-effect relation was constructed using the ethanol-induced gastric ulcer model in male Wistar rats. Histological analyses and studies of antioxidant and anti-inflammatory activities were performed in stomach samples. The involvement of SH compounds, NO, K+ ATP channels, and α 2-adrenergic receptors in the gastroprotective effect was evaluated. A toxicity study was performed with a single oral dose of 5000 mg/kg. The extract was composed mainly of cyanoglucoside and flavonol-O-glycosides derivatives of quercetin and myricetin. SH compounds, NO release, K+ ATP channel activation, and presynaptic α 2-adrenergic receptor stimulation each proved to be involved in the antiulcer effect. The levels of GSH and activity of GR and GPx were increased, and the levels of TNF-α, IL-6 and IL-10 were modulated. There was an antidiarrheal effect and there were no signs of toxicity. B. holophylla presents antiulcer activity mainly by decreasing oxidative stress and attenuating the inflammatory response, without inducing side effects. PMID:25954316

  3. The Self Attenuation Correction for Holdup Measurements, a Historical Perspective

    International Nuclear Information System (INIS)

    Oberer, R. B.; Gunn, C. A.; Chiang, L. G.

    2006-01-01

    Self attenuation has historically caused both conceptual as well as measurement problems. The purpose of this paper is to eliminate some of the historical confusion by reviewing the mathematical basis and by comparing several methods of correcting for self attenuation focusing on transmission as a central concept

  4. When and Why Mimicry is Facilitated and Attenuated

    NARCIS (Netherlands)

    Stel, Mariëlle; van Dijk, Eric; van Baaren, Rick B.

    2016-01-01

    Although people tend to mimic others automatically, mimicry is facilitated or attenuated depending on the specific context. In the current paper, the authors discuss when mimicry is facilitated and attenuated depending on characteristics of situations, targets, and observers. On the basis of the

  5. Developement of a Light Attenuator Based on Glassy Reflections ...

    African Journals Online (AJOL)

    The light intensity control of a luminous source is a very important operation in many optical applications. Several types of light attenuator exploiting different optical phenomena like diffraction, absorption, and reflection exist and they differ principally in the maximum attenuation rate, the control range, the sensitivity and the ...

  6. Statistical problems with weather-radar images, II: Attenuation detection

    International Nuclear Information System (INIS)

    Fernandez-Duran, Juan-Jose; Upton, Graham

    2003-01-01

    A procedure based on the combination of a Bayesian changepoint model and ordinary least squares is used to identify and quantify regions where a radar signal has been attenuated (i.e.diminished) as a consequence of intervening weather. A graphical polar display is introduced that illustrates the location and importance of the attenuation

  7. Attenuated radon transform: theory and application in medicine and biology

    Energy Technology Data Exchange (ETDEWEB)

    Gullberg, G.T.

    1979-06-01

    A detailed analysis is given of the properties of the attenuated Radon transform and of how increases in photon attenuation influence the numerical accuracy and computation efficiency of iterative and convolution algorithms used to determine its inversion. The practical applications for this work involve quantitative assessment of the distribution of injected radiopharmaceuticals and radionuclides in man and animals for basic physiological and biochemical studies as well as clinical studies in nuclear medicine. A mathematical structure is developed using function theory and the theory of linear operators on Hilbert spaces which lends itself to better understanding the spectral properties of the attenuated Radon transform. The continuous attenuated Radon transform reduces to a matrix operator for discrete angular and lateral sampling, and the reconstruction problem reduces to a system of linear equations. For the situation of variable attenuation coefficient frequently found in nuclear medicine applications of imaging the heart and chest, the procedure developed in this thesis involves iterative techniques of performing the generalized inverse. For constant attenuation coefficient less than 0.15 cm/sup -1/, convolution methods can reliably reconstruct a 30 cm object with 0.5 cm resolution. However, for high attenuation coefficients or for the situation where there is variable attenuation such as reconstruction of distribution of isotopes in the heart, iterative techniques developed in this thesis give the best results. (ERB)

  8. An attenuation measurement technique for rotating planar detector positron tomographs

    International Nuclear Information System (INIS)

    McNeil, P.A.; Julyan, P.J.; Parker, D.J.

    1997-01-01

    This paper presents a new attenuation measurement technique suitable for rotating planar detector positron tomographs. Transmission measurements are made using two unshielded positron-emitting line sources, one attached to the front face of each detector. Many of the scattered and accidental coincidences are rejected by including only those coincidences that form a vector passing within a predetermined distance of either line source. Some scattered and accidental coincidences are still included, which reduces the measured linear attenuation; in principle their contribution can be accurately estimated and subtracted, but in practice, when limited statistics are available (as is the case with the multi-wire Birmingham positron camera), this background subtraction unacceptably increases the noise. Instead an attenuation image having the correct features can be reconstructed from the measured projections. For objects containing only a few discrete linear attenuation coefficients, segmentation of this attenuation image reduces noise and allows the correct linear attenuation coefficients to be restored by renormalization. Reprojection through the segmented image may then provide quantitatively correct attenuation correction factors of sufficient statistical quality to correct for attenuation in PET emission images. (author)

  9. Lattice Boltzmann simulations of attenuation-driven acoustic streaming

    International Nuclear Information System (INIS)

    Haydock, David; Yeomans, J M

    2003-01-01

    We show that lattice Boltzmann simulations can be used to model the attenuation-driven acoustic streaming produced by a travelling wave. Comparisons are made to analytical results and to the streaming pattern produced by an imposed body force approximating the Reynolds stresses. We predict the streaming patterns around a porous material in an attenuating acoustic field

  10. Toxic Release Inventory Chemicals by Groupings

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Toxics Release Inventory (TRI) makes available information for more than 600 toxic chemicals that are being used, manufactured, treated, transported, or released...

  11. Information Search of Toxic-Free Ammunition

    National Research Council Canada - National Science Library

    Adelman, Stephen

    1994-01-01

    Task Order No. 0001, Information Search of Toxic-Free Ammunition addresses issues related to toxic and environmentally harmful effects caused by the use of some of the current small arms ammunition...

  12. Agency for Toxic Substances and Disease Registry

    Science.gov (United States)

    ... Z # Search Form Controls Search The CDC submit Agency for Toxic Substances and Disease Registry Note: Javascript ... gov . Recommend on Facebook Tweet Share Compartir The Agency for Toxic Substances and Disease Registry (ATSDR) , based ...

  13. Toxic chemicals: risk prevention through use reduction

    National Research Council Canada - National Science Library

    Higgins, Thomas E; Sachdev, Jayanti A; Engleman, Stephen A

    2011-01-01

    ... on the actual toxicity of chemicals currently in use, discusses variables that contribute to the relative toxicity of a substance, compares alternate emphases in existing programs for reducing environmental...

  14. Health risks associated with inhaled nasal toxicants

    NARCIS (Netherlands)

    Feron, VJ; Arts, JHE; Kuper, CF; Slootweg, PJ; Woutersen, RA

    2001-01-01

    Health risks of inhaled nasal toxicants were reviewed with emphasis on chemically induced nasal lesions in humans, sensory irritation, olfactory and trigeminal nerve toxicity, nasal immunopathology and carcinogenesis, nasal responses to chemical mixtures, in vitro models, and nasal dosimetry- and

  15. Methylmercury toxicity and functional programming

    DEFF Research Database (Denmark)

    Grandjean, Philippe

    2007-01-01

    : Accumulating evidence indicates that adverse effects may occur even at low-level methylmercury exposures from seafood and freshwater fish. Neurobehavioral outcomes are usually non-specific, and imprecise exposure assessment results in a bias toward the null. Essential nutrients may promote the development......PURPOSE: Adverse health effects of developmental toxicants may induce abnormal functional programming that leads to lasting functional deficits. This notion is considered from epidemiological evidence using developmental methylmercury neurotoxicity as an example. MOST IMPORTANT FINDINGS...... of certain brain functions, thereby causing confounding bias. The functional deficits caused by prenatal methylmercury exposure appear to be permanent, and their extent may depend on the joint effect of toxicants and nutrients. PRINCIPAL CONCLUSIONS: The lasting functional changes caused...

  16. Behavioral toxicity of selected radioprotectors

    Science.gov (United States)

    Landauer, M. R.; Davis, H. D.; Kumar, K. S.; Weiss, J. F.

    1992-10-01

    Effective radioprotection with minimal behavioral disruption is essential for the selection of protective agents to be used in manned spaceflight. This overview summarizes the studies on the behavioral toxicity of selected radioprotectors classified as phosphorothioates (WR-2721, WR-3689), bioactive lipids (16, 16 dimethylprostaglandin E2(DiPGE2), platelet activating factor (PAF), leukotriene C4), and immunomodulators (glucan, synthetic trehalose dicorynomycolate, and interleukin-1). Behavioral toxicity was examined in laboratory mice using a locomotor activity test. For all compounds tested, there was a dose-dependent decrease in locomotor behavior that paralleled the dose-dependent increase in radioprotection. While combinations of radioprotective compounds (DiPGE2 plus WR-2721) increased radioprotection, they also decreased locomotor activity. The central nervous system stimulant, caffeine, was able to mitigate the locomotor decrement produced by WR-3689 or PAF.

  17. Toxic Anterior Segment Syndrome (TASS

    Directory of Open Access Journals (Sweden)

    Özlem Öner

    2011-12-01

    Full Text Available Toxic anterior segment syndrome (TASS is a sterile intraocular inflammation caused by noninfectious substances, resulting in extensive toxic damage to the intraocular tissues. Possible etiologic factors of TASS include surgical trauma, bacterial endotoxin, intraocular solutions with inappropriate pH and osmolality, preservatives, denatured ophthalmic viscosurgical devices (OVD, inadequate sterilization, cleaning and rinsing of surgical devices, intraocular lenses, polishing and sterilizing compounds which are related to intraocular lenses. The characteristic signs and symptoms such as blurred vision, corneal edema, hypopyon and nonreactive pupil usually occur 24 hours after the cataract surgery. The differential diagnosis of TASS from infectious endophthalmitis is important. The main treatment for TASS formation is prevention. TASS is a cataract surgery complication that is more commonly seen nowadays. In this article, the possible underlying causes as well as treatment and prevention methods of TASS are summarized. (Turk J Oph thal mol 2011; 41: 407-13

  18. Small molecule fluoride toxicity agonists.

    Science.gov (United States)

    Nelson, James W; Plummer, Mark S; Blount, Kenneth F; Ames, Tyler D; Breaker, Ronald R

    2015-04-23

    Fluoride is a ubiquitous anion that inhibits a wide variety of metabolic processes. Here, we report the identification of a series of compounds that enhance fluoride toxicity in Escherichia coli and Streptococcus mutans. These molecules were isolated by using a high-throughput screen (HTS) for compounds that increase intracellular fluoride levels as determined via a fluoride riboswitch reporter fusion construct. A series of derivatives were synthesized to examine structure-activity relationships, leading to the identification of compounds with improved activity. Thus, we demonstrate that small molecule fluoride toxicity agonists can be identified by HTS from existing chemical libraries by exploiting a natural fluoride riboswitch. In addition, our findings suggest that some molecules might be further optimized to function as binary antibacterial agents when combined with fluoride. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Salicylate toxicity model of tinnitus

    Directory of Open Access Journals (Sweden)

    Daniel eStolzberg

    2012-04-01

    Full Text Available Salicylate, the active component of the common drug aspirin, has mild analgesic, antipyretic, and anti-inflammatory effects at moderate doses. At higher doses, however, salicylate temporarily induces moderate hearing loss and the perception of a high-pitch ringing in humans and animals. This phantom perception of sound known as tinnitus is qualitatively similar to the persistent subjective tinnitus induced by high-level noise exposure, ototoxic drugs or aging which affects ~14% of the general population. For over a quarter century, auditory scientists have used the salicylate toxicity model to investigate candidate biochemical and neurophysiological mechanisms underlying phantom sound perception. In this review, we summarize some of the intriguing biochemical and physiological effects associated with salicylate-induced tinnitus, some of which occur in the periphery and others in the central nervous system. The relevance and general utility of the salicylate toxicity model in understanding phantom sound perception in general are discussed.

  20. Attenuation correction for the NIH ATLAS small animal PET scanner

    CERN Document Server

    Yao, Rutao; Liow, JeihSan; Seidel, Jurgen

    2003-01-01

    We evaluated two methods of attenuation correction for the NIH ATLAS small animal PET scanner: 1) a CT-based method that derives 511 keV attenuation coefficients (mu) by extrapolation from spatially registered CT images; and 2) an analytic method based on the body outline of emission images and an empirical mu. A specially fabricated attenuation calibration phantom with cylindrical inserts that mimic different body tissues was used to derive the relationship to convert CT values to (I for PET. The methods were applied to three test data sets: 1) a uniform cylinder phantom, 2) the attenuation calibration phantom, and 3) a mouse injected with left bracket **1**8F right bracket FDG. The CT-based attenuation correction factors were larger in non-uniform regions of the imaging subject, e.g. mouse head, than the analytic method. The two methods had similar correction factors for regions with uniform density and detectable emission source distributions.

  1. FLUORIDE TOXICITY – A HARSH REALITY

    OpenAIRE

    Bandlapalli Pavani; Mandava Ragini; David Banji; Otilia J F Banji; N Gouri Pratusha

    2011-01-01

    There are many incidents of fluoride toxicity whether it is acute or chronic. Fluoride toxicity is an environmental hazard which arises from the upper layers of geological crust and is dissolved in water. Prolonged drinking of such water causes chronic fluoride toxicity. Use of fluoride containing compounds for various purposes such as dental products, metal, glass, refrigerator and chemical industries act as a source of fluoride poisoning and increase the risk of toxicity. This review reflec...

  2. Abacavir-induced liver toxicity

    Directory of Open Access Journals (Sweden)

    Maria Diletta Pezzani

    2016-09-01

    Full Text Available Abacavir-induced liver toxicity is a rare event almost exclusively occurring in HLA B*5701-positive patients. Herein, we report one case of abnormal liver function tests occurring in a young HLA B*5701-negative woman on a stable nevirapine-based regimen with no history of liver problems or alcohol abuse after switching to abacavir from tenofovir. We also investigated the reasons for abacavir discontinuation in a cohort of patients treated with abacavir-lamivudine-nevirapine.

  3. Acute and chronic arsenic toxicity

    OpenAIRE

    Ratnaike, R

    2003-01-01

    Arsenic toxicity is a global health problem affecting many millions of people. Contamination is caused by arsenic from natural geological sources leaching into aquifers, contaminating drinking water and may also occur from mining and other industrial processes. Arsenic is present as a contaminant in many traditional remedies. Arsenic trioxide is now used to treat acute promyelocytic leukaemia. Absorption occurs predominantly from ingestion from the small intestine, though minimal absorption o...

  4. Toxic metals in the atmosphere

    International Nuclear Information System (INIS)

    Munoz-Ribadeneira, F.J.; Mo, T.; Canoy, M.J.

    1975-05-01

    Methods used in Puerto Rico for monitoring toxic metals in the atmosphere are described. Air sampling machines are placed at heights from 15 to 25 ft above the surface and the tapes are subjected to neutron activation and γ spectroscopy. The concentrations of up to 33 elements can be determined with precision and sensitivity without destroying the tapes, which can then be used for analysis by other methods. (U.S.)

  5. Plant responses to metal toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Briat, J.F. [Montpellier-2 Univ., 34 (France). Biochimie et physiologie moleculaire des plantes, CNRS, URA 2133; Lebrun, M. [Montpellier-2 Univ., 34 (France). Biochimie et physiologie vegetale appliquee

    1999-01-01

    Increased metal concentration in the soils, up to toxic levels, is becoming an important environmental problem. Safety rule evolution will require solutions in order to cope with food safety rules, and to freeze metal leakage from heavily metal-poisoned soils, such as those from industrial fallows. In this context, plants could serve to develop bio-assays in order to promote new standards, more realistic than the mass of a given metal per kg of soil, that does not consider the metal bio-disponibility. Plants could also be used for phyto-extraction and/or phyto-stabilization. To reach these objectives, a genetic approach could be useful to generate metal-tolerant plants with enough biomass. In this work is more particularly studied the plant responses to metal toxicity. Metal toxicity for living organisms involves oxidative and /or genotoxic mechanisms. Plant protection against metal toxicity occurs, at least in part, through control of root metal uptake and of long distance metal transport. Inside cells, proteins such as ferritins and metallothioneins, and glutathione-derived peptides named phyto-chelatins, participate in excess metal storage and detoxification. Low molecular weight organic molecules, mainly organic acids and amino acids and their derivatives, also play an important role in plant metal homeostasis. When these systems are overloaded, oxidative stress defense mechanisms are activated. Molecular and cellular knowledge of these processes will be necessary to improve plant metal resistance. Occurrence of naturally tolerant plants which hyper accumulate metals provides helpful tools for this research. (authors) 130 refs.

  6. Developmental toxicity of engineered nanomaterials

    DEFF Research Database (Denmark)

    Hougaard, Karin S.; Hansen, Jitka S.; Jackson, Petra

    2016-01-01

    Study of air pollution indicates that minute particles may adversely interfere with pregnancy and fetal development. As engineering of nanoparticles have emerged, so has concern that these might interfere with reproductive and developmental functions. This is because nanotechnology may potentially...... increase the overall particle burden in air and introduce particles with novel characteristics and surface reactivity. To evaluate safety for pregnant women, we have studied developmental toxicity of engineered nanoparticles (ENPs), following exposure of pregnant mice by inhalation (ENPs of titanium...

  7. Coumafuryl (Fumarin) toxicity in chicks.

    Science.gov (United States)

    Munger, L L; Su, J J; Barnes, H J

    1993-01-01

    Coumafuryl (Fumarin) toxicity was diagnosed in chickens less than 1 week of age. Mortality rate was 100%. Necropsy showed crops and gizzards to be full of feed. There was diffuse hemorrhage and unclotted blood in the abdomen and thorax. Histological examination showed congestion and hemorrhage. Chemical analysis of crop and gizzard contents contained approximately 340 ppm coumafuryl. The source of the coumafuryl was found to be the wood-straw mats in the chick boxes.

  8. Pathological features of glutaminase toxicity.

    Science.gov (United States)

    Baskerville, A.; Hambleton, P.; Benbough, J. E.

    1980-01-01

    In an investigation of the toxicity of the anti-tumour enzyme glutaminase Rhesus monkeys, marmosets, rabbits and mice were given various doses of chemically modified glutaminase parenterally. The enzyme induced diarrhoea and dysentery and at all but the lowest doses caused illness which was fatal within 10 days. Pathological lesions produced were hepatic lipidosis and glycogen accumulation, and, in the primates, acute necrotizing colitis. Images Fig. 1 Fig. 2 PMID:6775661

  9. Dietary zinc and its toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Lantzsch, H J

    1973-01-01

    First signs of Zn-toxicity in rats appeared at 1000 to 2000 ppm Zn in food. They were characterized by growth inhibition by the appearance of a microcytic hypochromic anemia by a reversible impairment of the ability to reproduce by disturbances in fat metabolism and by Zn-accumulation especially in the liver and the skeleton. Available results in the literature concerning alimentary Zn-toxicity in horses are few. At a daily doses of 8000 mg Zn during gestation there were no noticeable adverse effects either in the mare or the foal. While with young lambs addition of Zn of up to 1000 ppm enhanced growth, food intake and feed efficiency, with older lambs it gave rise to depressions. Available results of experiments with milk cows are equally insufficient. At Zn-concentration of 40 to 80 ppm, which may be reached in normal foodstuff, there appears to be a disturbance in the metabolism of cellulose in the rumen. In spite of this fact and notwithstanding the insufficiently examined influence of high Zn-concentrations in food on the Cu-metabolism, the limit of Zn-tolerance can be given at 1000 mg per kg of food. If dissolved, Zn is far more toxic. With calves there wre no signs of clinical toxicity up to Zn-concentrations in the food of 3000 ppm. Above 900 ppm there appeared depression in growth and deterioration in the feed efficiency. Ae 1700 ppm there was a decrease infood intake. Increased Zn-intake lead to a growing Zn-accumulation in several organs and tissues, with the accumulation in the liver, bones, kidneys, pancreas and the gastrointestinal tract being of special significance. With cessation of Zn-intake in food, Zn-accumulation slowly disappeared. As a result of high Zn-intake there appears to be synergistic and antagonistic interdependent effects with the metabolism of other trace elements (Cu, Fe) and minerals (Ca, Na, P).

  10. Mobilisation and attenuation of boron during coal mine rehabilitation, Wangaloa, New Zealand

    International Nuclear Information System (INIS)

    Craw, D.; Rufaut, C.G.; Haffert, L.; Todd, A.

    2006-01-01

    Environmental mobility and fate of boron has been traced from source to discharge waters through the rehabilitated Wangaloa coal mine in southern New Zealand. The boron is derived initially from coal, which has up to 450 mg/kg B. The coal also contains pyrite (2-5 wt.% S), which oxidizes to yield a low-pH environment (typical pH 2-5). Weathering of coal-bearing waste rock liberates B into rainwater that infiltrates into waste rock or evaporates to leave a gypsum crust enriched in B, possibly as boric acid or colemanite as inferred from geochemical modelling. Surface waters dissolve this evaporative material periodically, yielding total B concentrations up to 6 mg/L, at pH<4.5. Some of the available B is taken up by plants that have been established on the waste rock, resulting in foliage B concentrations of up to 230 mg/kg (dry weight). Partial attenuation of dissolved B by adsorption to iron oxyhydroxide occurs as groundwater passes through waste rock, but this is inhibited by adsorption competition with dissolved sulphate (up to 600 mg/L). Groundwater flows from the mine through a pit lake and wetland, with total dissolved B near 1 mg/kg after dilution and limited adsorption attenuation has occurred. Despite the widespread B mobility throughout the rehabilitated mine, there is little evidence of B toxicity in plants. The B concentrations in discharging waters are in the environmentally safe range for most aquatic organisms, being neither deficient in B as a micronutrient, nor boron-toxic. (author)

  11. [Investigation of potential toxic factors for fleece-flower root: from perspective of processing methods evolution].

    Science.gov (United States)

    Cui, He-Rong; Bai, Zhao-Fang; Song, Hai-Bo; Jia, Tian-Zhu; Wang, Jia-Bo; Xiao, Xiao-He

    2016-01-01

    In recent years, the rapid growth of reports on fleece-flower root-caused liver damages has drawn wide attention of both at home and abroad, however, there were rare literature on toxicology of fleece-flower root in ancient Chinese medicine. But why there are so many reports on toxicology of fleece-flower root now compared with the ancient literature? As a typical tonic medicine, the clinical utility of fleece-flower root was largely limited by its standardization and reliability of processing methods in ancient Chinese medicine. The ancient processing methods of fleece-flower root emphasized nine times of steaming and nine times of drying, while the modern processes have been simplified into one time of steaming. Whether the differences between ancient and modern processing methods are the potential cause of the increased events of fleece-flower root-caused liver damages. We will make deep analysis and provide new clues and perspectives for the research on its toxicity. This article, therefore, would discuss the affecting factors and key problems in toxicity attenuation of fleece-flower root on the basis of sorting out the processing methods of fleece-flower root in ancient medical books and modern standards, in order to provide the reference for establishing specification for toxicity attenuation of fleece-flower root. Copyright© by the Chinese Pharmaceutical Association.

  12. Attenuation of earmuffs used simultaneously with respiratory protective devices

    Directory of Open Access Journals (Sweden)

    Emil Kozłowski

    2017-06-01

    Full Text Available Background: In the work environment, apart from the noise, employees may be exposed to other harmful factors. Therefore, they wear hearing protectors and other personal protective equipment. The aim of the study was to determine whether simultaneous use of earmuffs and respiratory protective devices affects the attenuation of earmuffs. Material and Methods: The study was conducted in laboratory conditions using the subjective REAT (Real Ear Attenuation at Threshold and objective MIRE (Microphone in Real Ear methods. The REAT method was used to measure sound attenuation of earmuffs, while MIRE was used to determine changes in attenuation of earmuffs due to the use of other personal protective equipment. Results: The study showed reduction in attenuation of earmuffs due to the use of a full face mask up to 20 dB. Using a full face mask causes that attenuation of earmuffs in the low frequency range is close to zero. Reduction in attenuation due to the use of half masks for complete with particle filters (half masks is 3–15 dB. Simultaneous use of earmuffs and filtering half masks makes small changes in attenuation not exceeding 3 dB. Conclusions: The study showed that full face masks give the greatest reduction in attenuation of earmuffs. On the other hand, the least reduction is observed in the case of filtering half masks. There is a significant difference between the reduction in attenuation of earmuffs worn with half masks for complete with particle filters because they may be equipped with different kind of the head strap. Med Pr 2017;68(3:349–361

  13. The politics of toxic waste

    International Nuclear Information System (INIS)

    Rahm, D.

    1998-01-01

    Toxic waste, and the public policy that deals with it, is a complex issue. Much of the complexity stems from the science and technology embedded in the topic, but a great deal also results from the intricate interactions between the social organizations and institutions involved. The politics of toxic waste plays out within three key aspects of this complexity. The first of these is the nature of the intergovernmental relations involved. For toxic waste issues, these intergovernmental relations can be between sovereign states or between a nation and an international governing organization, or they may be restricted to a domestic context. If the later is the case, the relationship can be between federal, state, and local governments or between different bureaus, departments, or agencies within the same level of government. A second feature of this complexity can be seen in the consequences of divergent organizational or institutional interests. When conflicting organizational or institutional perspectives, positions, or concerns arise, public policy outcomes are affected.The tug and pull of competing actors move policy in the direction favored by the winner. This may or may not be the most rational alternative. A third aspect of this interorganizational puzzle involves the question of where the locus of authority for decisionmaking resides and to what extent stakeholders, who do not possess direct authority, can influence policy outcomes

  14. Backscatter and attenuation characterization of ventricular myocardium

    Science.gov (United States)

    Gibson, Allyson Ann

    2009-12-01

    This Dissertation presents quantitative ultrasonic measurements of the myocardium in fetal hearts and adult human hearts with the goal of studying the physics of sound waves incident upon anisotropic and inhomogeneous materials. Ultrasound has been used as a clinical tool to assess heart structure and function for several decades. The clinical usefulness of this noninvasive approach has grown with our understanding of the physical mechanisms underlying the interaction of ultrasonic waves with the myocardium. In this Dissertation, integrated backscatter and attenuation analyses were performed on midgestational fetal hearts to assess potential differences in the left and right ventricular myocardium. The hearts were interrogated using a 50 MHz transducer that enabled finer spatial resolution than could be achieved at more typical clinical frequencies. Ultrasonic data analyses demonstrated different patterns and relative levels of backscatter and attenuation from the myocardium of the left ventricle and the right ventricle. Ultrasonic data of adult human hearts were acquired with a clinical imaging system and quantified by their magnitude and time delay of cyclic variation of myocardial backscatter. The results were analyzing using Bayes Classification and ROC analysis to quantify potential advantages of using a combination of two features of cyclic variation of myocardial backscatter over using only one or the other feature to distinguish between groups of subjects. When the subjects were classified based on hemoglobin A1c, the homeostasis model assessment of insulin resistance, and the ratio of triglyceride to high-density lipoprotein-cholesterol, differences in the magnitude and normalized time delay of cyclic variation of myocardial backscatter were observed. The cyclic variation results also suggested a trend toward a larger area under the ROC curve when information from magnitude and time delay of cyclic variation is combined using Bayes classification than when

  15. Joint toxic effects on Caenorhabditis elegans

    NARCIS (Netherlands)

    Jonker, M.J.

    2003-01-01

    In polluted areas organisms are generally exposed to mixtures of toxic chemicals rather than a single toxicant only. Since the number of mixture toxicity studies with regard to soil systems is limited, the research in this thesis was focused on investigating ecotoxicological consequences of

  16. Toxicity of pyrolysis gases from polyether sulfone

    Science.gov (United States)

    Hilado, C. J.; Olcomendy, E. M.

    1979-01-01

    A sample of polyether sulfone was evaluated for toxicity of pyrolysis gases, using the toxicity screening test method developed at the University of San Francisco. Animal response times were relatively short at pyrolysis temperatures of 600 to 800 C, with death occurring within 6 min. The principal toxicant appeared to be a compound other than carbon monoxide.

  17. Hormetic Effect of Berberine Attenuates the Anticancer Activity of Chemotherapeutic Agents.

    Directory of Open Access Journals (Sweden)

    Jiaolin Bao

    Full Text Available Hormesis is a phenomenon of biphasic dose response characterized by exhibiting stimulatory or beneficial effects at low doses and inhibitory or toxic effects at high doses. Increasing numbers of chemicals of various types have been shown to induce apparent hormetic effect on cancer cells. However, the underlying significance and mechanisms remain to be elucidated. Berberine, one of the major active components of Rhizoma coptidis, has been manifested with notable anticancer activities. This study aims to investigate the hormetic effect of berberine and its influence on the anticancer activities of chemotherapeutic agents. Our results demonstrated that berberine at low dose range (1.25 ~ 5 μM promoted cell proliferation to 112% ~170% of the untreated control in various cancer cells, while berberine at high dose rage (10 ~ 80 μM inhibited cell proliferation. Further, we observed that co-treatment with low dose berberine could significantly attenuate the anticancer activity of chemotherapeutic agents, including fluorouracil (5-FU, camptothecin (CPT, and paclitaxel (TAX. The hormetic effect and thereby the attenuated anticancer activity of chemotherapeutic drugs by berberine may attributable to the activated protective stress response in cancer cells triggered by berberine, as evidenced by up-regulated MAPK/ERK1/2 and PI3K/AKT signaling pathways. These results provided important information to understand the potential side effects of hormesis, and suggested cautious application of natural compounds and relevant herbs in adjuvant treatment of cancer.

  18. Determination of mass attenuation coefficient in wood and leaves of typical trees by gamma-ray attenuation technique

    International Nuclear Information System (INIS)

    Miranda, Regina M. de; Pascholati, Elisabete M.

    1997-01-01

    Using an 241 Am source the mass attenuation coefficient of different woods and leaves of typical species of the Atlantic Forest were measured. The results for natural wood, dry wood and dry leaves indicate that the variation is very small among different species. However, woods present a higher attenuation than leaves, both depending on their water content. (author). 10 refs., 3 figs., 1 tab

  19. Melatonin attenuates thiocyanate-induced vasoconstriction in aortic rings

    Directory of Open Access Journals (Sweden)

    Alexander M. Prusa

    2017-11-01

    Full Text Available Cigarette smoking not only has a carcinogenic effect but also leads to an increase in arterial blood pressure. Besides its main components, i.e. nicotine, tar, and carbon monoxide, cigarette smoke also contains thiocyanate. Thiocyanate anions (SCN− arise from the detoxification of hydrogen cyanide and its plasma concentrations were found to correlate significantly with cigarette consumption. There is also evidence that atherosclerotic disease progression is much more rapid when serum SCN− levels are increased. Melatonin, a non-toxic indolamine with various physiologic functions, is believed to protect against inflammatory processes and oxidative stress. It has been demonstrated that melatonin serves as free radical scavenger and represents a potent antioxidant. Therefore, it is believed that melatonin with its atheroprotective effects may be useful either as a sole therapy or in conjunction with others. The aim of this study was to quantify the thiocyanate-induced vasomotor response in aortic tissue and further to examine the potential of melatonin in affecting the generated vasoreactivity. Aortic rings of adult male normotensive Wistar rats were cut into 4-mm rings. Following the administration of thiocyanate in various concentrations, vasomotor response of aortic vessel segments was measured. To assess the effect of melatonin on vasomotor activity, organ bath concentrations were modulated from 60 to 360 pM, which corresponds to physiologic plasma up to the levels of patients with regular oral intake of 3 mg of melatonin as a supplement. Thirty-six rat aortic rings were studied. When exposed to thiocyanate, vessel segments revealed vasoconstriction in a concentration-dependent manner. In rings which were preincubated with melatonin at a concentration of 360 pM, a 56.5% reduction of effect size could be achieved (4.09 ± 1.22 mN versus 9.41 ± 1.74 mN, P < 0.0001. Additionally, administration of 360 pM melatonin at a

  20. Endogenous cueing attenuates object substitution masking.

    Science.gov (United States)

    Germeys, Filip; Pomianowska, I; De Graef, P; Zaenen, P; Verfaillie, K

    2010-07-01

    Object substitution masking (OSM) is a form of visual masking in which a briefly presented target surrounded by four small dots is masked by the continuing presence of the four dots after target offset. A major parameter in the prediction of OSM is the time required for attention to be directed to the target following its onset. Object substitution theory (Di Lollo et al. in J Exp Psychol Gen 129:481-507, 2000) predicts that the sooner attention can be focused at the target's location, the less masking will ensue. However, recently Luiga and Bachmann (Psychol Res 71:634-640, 2007) presented evidence that precueing of attention to the target location prior to target-plus-mask onset by means of a central (endogenous) arrow cue does not reduce OSM. When attention was cued exogenously, OSM was attenuated. Based on these results, Luiga and Bachmann argued that object substitution theory should be adapted by differentiating the ways of directing attention to the target location. The goal of the present study was to further examine the dissociation between the effects of endogenous and exogenous precueing on OSM. Contrary to Luiga and Bachmann, our results show that prior shifts of attention to the target location initiated by both exogenous and endogenous cues reduce OSM as predicted by object substitution theory and its computational model CMOS.

  1. Silibinin attenuates allergic airway inflammation in mice

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Yun Ho [Department of Anatomy, Medical School, Institute for Medical Sciences, Chonbuk National University, Jeonju, Jeonbuk 561-756 (Korea, Republic of); Jin, Guang Yu [Department of Radiology, Yanbian University Hospital, YanJi 133002 (China); Guo, Hui Shu [Centralab, The First Affiliated Hospital of Dalian Medical University, Dalian 116011 (China); Piao, Hong Mei [Department of Respiratory Medicine, Yanbian University Hospital, YanJi 133000 (China); Li, Liang chang; Li, Guang Zhao [Department of Anatomy and Histology and Embryology, Yanbian University School of Basic Medical Sciences, 977 Gongyuan Road, YanJi 133002, Jilin (China); Lin, Zhen Hua [Department of Pathology, Yanbian University School of Basic Medical Sciences, YanJi 133000 (China); Yan, Guang Hai, E-mail: ghyan@ybu.edu.cn [Department of Anatomy and Histology and Embryology, Yanbian University School of Basic Medical Sciences, 977 Gongyuan Road, YanJi 133002, Jilin (China)

    2012-10-26

    Highlights: Black-Right-Pointing-Pointer Silibinin diminishes ovalbumin-induced inflammatory reactions in the mouse lung. Black-Right-Pointing-Pointer Silibinin reduces the levels of various cytokines into the lung of allergic mice. Black-Right-Pointing-Pointer Silibinin prevents the development of airway hyperresponsiveness in allergic mice. Black-Right-Pointing-Pointer Silibinin suppresses NF-{kappa}B transcriptional activity. -- Abstract: Allergic asthma is a chronic inflammatory disease regulated by coordination of T-helper2 (Th2) type cytokines and inflammatory signal molecules. Silibinin is one of the main flavonoids produced by milk thistle, which is reported to inhibit the inflammatory response by suppressing the nuclear factor-kappa B (NF-{kappa}B) pathway. Because NF-{kappa}B activation plays a pivotal role in the pathogenesis of allergic inflammation, we have investigated the effect of silibinin on a mouse ovalbumin (OVA)-induced asthma model. Airway hyperresponsiveness, cytokines levels, and eosinophilic infiltration were analyzed in bronchoalveolar lavage fluid and lung tissue. Pretreatment of silibinin significantly inhibited airway inflammatory cell recruitment and peribronchiolar inflammation and reduced the production of various cytokines in bronchoalveolar fluid. In addition, silibinin prevented the development of airway hyperresponsiveness and attenuated the OVA challenge-induced NF-{kappa}B activation. These findings indicate that silibinin protects against OVA-induced airway inflammation, at least in part via downregulation of NF-{kappa}B activity. Our data support the utility of silibinin as a potential medicine for the treatment of asthma.

  2. Silibinin attenuates allergic airway inflammation in mice

    International Nuclear Information System (INIS)

    Choi, Yun Ho; Jin, Guang Yu; Guo, Hui Shu; Piao, Hong Mei; Li, Liang chang; Li, Guang Zhao; Lin, Zhen Hua; Yan, Guang Hai

    2012-01-01

    Highlights: ► Silibinin diminishes ovalbumin-induced inflammatory reactions in the mouse lung. ► Silibinin reduces the levels of various cytokines into the lung of allergic mice. ► Silibinin prevents the development of airway hyperresponsiveness in allergic mice. ► Silibinin suppresses NF-κB transcriptional activity. -- Abstract: Allergic asthma is a chronic inflammatory disease regulated by coordination of T-helper2 (Th2) type cytokines and inflammatory signal molecules. Silibinin is one of the main flavonoids produced by milk thistle, which is reported to inhibit the inflammatory response by suppressing the nuclear factor-kappa B (NF-κB) pathway. Because NF-κB activation plays a pivotal role in the pathogenesis of allergic inflammation, we have investigated the effect of silibinin on a mouse ovalbumin (OVA)-induced asthma model. Airway hyperresponsiveness, cytokines levels, and eosinophilic infiltration were analyzed in bronchoalveolar lavage fluid and lung tissue. Pretreatment of silibinin significantly inhibited airway inflammatory cell recruitment and peribronchiolar inflammation and reduced the production of various cytokines in bronchoalveolar fluid. In addition, silibinin prevented the development of airway hyperresponsiveness and attenuated the OVA challenge-induced NF-κB activation. These findings indicate that silibinin protects against OVA-induced airway inflammation, at least in part via downregulation of NF-κB activity. Our data support the utility of silibinin as a potential medicine for the treatment of asthma.

  3. Ursodeoxycholic acid attenuates colonic epithelial secretory function

    Science.gov (United States)

    Kelly, Orlaith B; Mroz, Magdalena S; Ward, Joseph B J; Colliva, Carolina; Scharl, Michael; Pellicciari, Roberto; Gilmer, John F; Fallon, Padraic G; Hofmann, Alan F; Roda, Aldo; Murray, Frank E; Keely, Stephen J

    2013-01-01

    Dihydroxy bile acids, such as chenodeoxycholic acid (CDCA), are well known to promote colonic fluid and electrolyte secretion, thereby causing diarrhoea associated with bile acid malabsorption. However, CDCA is rapidly metabolised by colonic bacteria to ursodeoxycholic acid (UDCA), the effects of which on epithelial transport are poorly characterised. Here, we investigated the role of UDCA in the regulation of colonic epithelial secretion. Cl− secretion was measured across voltage-clamped monolayers of T84 cells and muscle-stripped sections of mouse or human colon. Cell surface biotinylation was used to assess abundance/surface expression of transport proteins. Acute (15 min) treatment of T84 cells with bilateral UDCA attenuated Cl− secretory responses to the Ca2+ and cAMP-dependent secretagogues carbachol (CCh) and forskolin (FSK) to 14.0 ± 3.8 and 40.2 ± 7.4% of controls, respectively (n= 18, P acid (LCA). Accordingly, LCA (50–200 μm) enhanced agonist-induced secretory responses in vitro and a metabolically stable UDCA analogue, 6α-methyl-UDCA, exerted anti-secretory actions in vitro and in vivo. In conclusion, UDCA exerts direct anti-secretory actions on colonic epithelial cells and metabolically stable derivatives of the bile acid may offer a new approach for treating intestinal diseases associated with diarrhoea. PMID:23507881

  4. Assessment of satellite derived diffuse attenuation coefficients ...

    Science.gov (United States)

    Optical data collected in coastal waters off South Florida and in the Caribbean Sea between January 2009 and December 2010 were used to evaluate products derived with three bio-optical inversion algorithms applied to MOIDS/Aqua, MODIS/Terra, and SeaWiFS satellite observations. The products included the diffuse attenuation coefficient at 490 nm (Kd_490) and for the visible range (Kd_PAR), and euphotic depth (Zeu, corresponding to 1% of the surface incident photosynthetically available radiation or PAR). Above-water hyperspectral reflectance data collected over optically shallow waters of the Florida Keys between June 1997 and August 2011 were used to help understand algorithm performance over optically shallow waters. The in situ data covered a variety of water types in South Florida and the Caribbean Sea, ranging from deep clear waters, turbid coastal waters, and optically shallow waters (Kd_490 range of ~0.03 – 1.29m-1). An algorithm based on Inherent Optical Properties (IOPs) showed the best performance (RMSD turbidity or shallow bottom contamination. Similar results were obtained when only in situ data were used to evaluate algorithm performance. The excellent agreement between satellite-derived remote sensing reflectance (Rrs) and in situ Rrs suggested that

  5. Compensation for photon attenuation in PET

    International Nuclear Information System (INIS)

    Chintu Chen; Ordonez, C.E.; Xiaolin Yu.

    1992-01-01

    CT/MR and PET images usually are not in registration spatially because of differences in the imaging setup. CT, MR and PET imaging parameters that are used regularly for brain studies in their institution are compared, in addition, because the patient orientations in CT/MR and PET scanners are not the same, slice centers are positioned differently relative to the patients anatomy. For application of the new idea of using structural information from CT or MR images in PET image reconstruction for attenuation correction, image registration is required as a first step so that one can obtain a corresponding anatomic map for any selected PET image plane. The authors chose to use the surface-matching technique developed in their laboratories for image registration because this method is retrospective and accurate. After the PET and CT/MR scans are registered, they reslice the CT/MR images along the planes of the PET images. The differences in slice thickness and slice separation, as well as in image resolution between various image modalities are to be considered

  6. Reconstruction of multiple line source attenuation maps

    International Nuclear Information System (INIS)

    Celler, A.; Sitek, A.; Harrop, R.

    1996-01-01

    A simple configuration for a transmission source for the single photon emission computed tomography (SPECT) was proposed, which utilizes a series of collimated line sources parallel to the axis of rotation of a camera. The detector is equipped with a standard parallel hole collimator. We have demonstrated that this type of source configuration can be used to generate sufficient data for the reconstruction of the attenuation map when using 8-10 line sources spaced by 3.5-4.5 cm for a 30 x 40cm detector at 65cm distance from the sources. Transmission data for a nonuniform thorax phantom was simulated, then binned and reconstructed using filtered backprojection (FBP) and iterative methods. The optimum maps are obtained with data binned into 2-3 bins and FBP reconstruction. The activity in the source was investigated for uniform and exponential activity distributions, as well as the effect of gaps and overlaps of the neighboring fan beams. A prototype of the line source has been built and the experimental verification of the technique has started

  7. Transient hepatic attenuation differences in neonates

    International Nuclear Information System (INIS)

    Towbin, Alexander J.; Fleck, Robert; Ying, Jun

    2009-01-01

    A transient hepatic attenuation difference (THAD) is a hepatic perfusion anomaly seen on contrast-enhanced CT scans caused by an alteration in the dual blood supply of the liver. Although THADs have been described in adolescents and adults, they have not previously been described in neonates. We describe the appearance and evaluate the frequency of THADs in neonates ≤1 month of age compared to other infants younger than 2 years. A retrospective study was performed looking at all CT angiograms from 2000 to 2007 in infants <2 years of age. The incidence of THADs was compared among four age groups. Significance was determined using a logistic regression model. The study included 128 CT angiograms. A THAD was seen in 9/26 infants <1 month of age, in 3/50 infants 1 to 6 months of age, in 1/23 infants 6 months to 1 year of age, and in 1/29 infants 1 to 2 years of age. A THAD was found significantly more frequently in infants <1 month of age than in the older age groups (P<0.05). THADs are benign entities that can be seen normally in the neonatal age group. When the characteristic appearance is seen on CT, no further imaging is needed. (orig.)

  8. Statins attenuate polymethylmethacrylate-mediated monocyte activation.

    LENUS (Irish Health Repository)

    Laing, Alan J

    2012-02-03

    BACKGROUND: Periprosthetic osteolysis precipitates aseptic loosening of components, increases the risk of periprosthetic fracture and, through massive bone loss, complicates revision surgery and ultimately is the primary cause for failure of joint arthroplasty. The anti-inflammatory properties of HMG-CoA reductase inhibitors belonging to the statin family are well recognized. We investigated a possible role for status in initiating the first stage of the osteolytic cycle, namely monocytic activation. METHODS: We used an in vitro model of the human monocyte\\/macrophage inflammatory response to poly-methylmethacrylate (PMMA) particles after pretreat-ing cells with cerivastatin, a potent member of the statin family. Cell activation based upon production of TNF-alpha and MCP-1 cytokines was analyzed and the intracellular Raf-MEK-ERK signal transduction pathway was evaluated using western blot analysis, to identify its role in cell activation and in any cerivastatin effects observed. RESULTS: We found that pretreatment with cerivastatin significantly abrogates the production of inflammatory cytokines TNF-alpha and MCP-1 by human monocytes in response to polymethylmethacrylate particle activation. This inflammatory activation and attenuation appear to be mediated through the intracellular Raf-MEK-ERK pathway. INTERPRETATION: We propose that by intervening at the upstream activation stage, subsequent osteoclast activation and osteolysis can be suppressed. We believe that the anti-inflammatory properties of statins may potentially play a prophylactic role in the setting of aseptic loosening, and in so doing increase implant longevity.

  9. Minocycline Attenuates Iron-Induced Brain Injury.

    Science.gov (United States)

    Zhao, Fan; Xi, Guohua; Liu, Wenqaun; Keep, Richard F; Hua, Ya

    2016-01-01

    Iron plays an important role in brain injury after intracerebral hemorrhage (ICH). Our previous study found minocycline reduces iron overload after ICH. The present study examined the effects of minocycline on the subacute brain injury induced by iron. Rats had an intracaudate injection of 50 μl of saline, iron, or iron + minocycline. All the animals were euthanized at day 3. Rat brains were used for immunohistochemistry (n = 5-6 per each group) and Western blotting assay (n = 4). Brain swelling, blood-brain barrier (BBB) disruption, and iron-handling proteins were measured. We found that intracerebral injection of iron resulted in brain swelling, BBB disruption, and brain iron-handling protein upregulation (p minocycline with iron significantly reduced iron-induced brain swelling (n = 5, p Minocycline significantly decreased albumin protein levels in the ipsilateral basal ganglia (p minocycline co-injected animals. In conclusion, the present study suggests that minocycline attenuates brain swelling and BBB disruption via an iron-chelation mechanism.

  10. Obesity attenuates gender differences in cardiovascular mortality.

    Science.gov (United States)

    Song, Xin; Tabák, Adam G; Zethelius, Björn; Yudkin, John S; Söderberg, Stefan; Laatikainen, Tiina; Stehouwer, Coen D A; Dankner, Rachel; Jousilahti, Pekka; Onat, Altan; Nilsson, Peter M; Satman, Ilhan; Vaccaro, Olga; Tuomilehto, Jaakko; Qiao, Qing

    2014-10-19

    To estimate cardiovascular disease (CVD) mortality in relation to obesity and gender. Data from 11 prospective cohorts from four European countries including 23 629 men and 21 965 women, aged 24 to 99 years, with a median follow-up of 7.9 years were analyzed. Hazards ratios (HR) for CVD mortality in relation to baseline body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR) and waist-to-height ratio (WHtR) were estimated using Cox proportional hazards models with age as the timescale. Men had higher CVD mortality than women in all four BMI categories (obesity defined by WC, WHR or WHtR. The gender difference was slightly smaller in obese than in non-obese individuals; but the interaction was statistically significant only between gender and WC (p = 0.02), and WHtR (p = 0.01). None of the interaction terms was significant among non-diabetic individuals. Men had higher CVD mortality than women across categories of anthropometric measures of obesity. The gender difference was attenuated in obese individuals, which warrants further investigation.

  11. Toxic Stress: Effects, Prevention and Treatment

    Directory of Open Access Journals (Sweden)

    Hillary A. Franke

    2014-11-01

    Full Text Available Children who experience early life toxic stress are at risk of long-term adverse health effects that may not manifest until adulthood. This article briefly summarizes the findings in recent studies on toxic stress and childhood adversity following the publication of the American Academy of Pediatrics (AAP Policy Report on the effects of toxic stress. A review of toxic stress and its effects is described, including factors of vulnerability, resilience, and the relaxation response. An integrative approach to the prevention and treatment of toxic stress necessitates individual, community and national focus.

  12. An acoustic eikonal equation for attenuating orthorhombic media

    KAUST Repository

    Hao, Qi

    2017-04-06

    Attenuating orthorhombic models are often used to describe the azimuthal variation of the seismic wave velocity and amplitude in finely layered hydrocarbon reservoirs with vertical fractures. In addition to the P-wave related medium parameters, shear wave parameters are also present in the complex eikonal equation needed to describe the P-wave complex-valued traveltime in an attenuating orthorhombic medium, which increases the complexity of using the P-wave traveltime to invert for the medium parameters in practice. Here, we use the acoustic assumption to derive an acoustic eikonal equation that approximately governs the complex-valued traveltime of P-waves in an attenuating orthorhombic medium. For a homogeneous attenuating orthorhombic media, we solve the eikonal equation using a combination of the perturbation method and Shanks transform. For a horizontal attenuating orthorhombic layer, both the real and imaginary part of the complex-valued reflection traveltime have nonhyperbolic behaviors in terms of the source-receiver offset. Similar to the roles of normal moveout (NMO) velocity and anellipticity, the attenuation NMO velocity and the attenuation anellipticity characterize the variation of the imaginary part of the complex-valued reflection traveltime around zero source-receiver offset.

  13. Believing and perceiving: authorship belief modulates sensory attenuation.

    Directory of Open Access Journals (Sweden)

    Andrea Desantis

    Full Text Available Sensory attenuation refers to the observation that self-generated stimuli are attenuated, both in terms of their phenomenology and their cortical response compared to the same stimuli when generated externally. Accordingly, it has been assumed that sensory attenuation might help individuals to determine whether a sensory event was caused by themselves or not. In the present study, we investigated whether this dependency is reciprocal, namely whether sensory attenuation is modulated by prior beliefs of authorship. Participants had to judge the loudness of auditory effects that they believed were either self-generated or triggered by another person. However, in reality, the sounds were always triggered by the participants' actions. Participants perceived the tones' loudness attenuated when they believed that the sounds were self-generated compared to when they believed that they were generated by another person. Sensory attenuation is considered to contribute to the emergence of people's belief of authorship. Our results suggest that sensory attenuation is also a consequence of prior belief about the causal link between an action and a sensory change in the environment.

  14. Pulmonary toxicity of manufactured nanoparticles

    Science.gov (United States)

    Peebles, Brian Christopher

    Manufactured nanomaterials have become ubiquitous in science, industry, and medicine. Although electron microscopy and surface probe techniques have improved understanding of the physicochemical properties of nanomaterials, much less is known about what makes nanomaterials toxic. Particulate matter less than 2.5 mum in effective aerodynamic diameter is easily inhaled and taken deep into the lungs. The toxicity of inhaled particulate matter is related to its size and surface chemistry; for instance, the smaller the size of particles, the greater their specific surface area. The chemistry and toxicity of insoluble particles depends on their surface area, since chemical reactions may happen with the environment on the surface. Oxidation and reduction may occur on the surfaces of particles after they are produced. For instance, it is known that carbonaceous particles from vehicle exhaust and industrial emission may interact with reactive species like ozone in their ambient environment, altering the surface chemistry of the particles. Reaction with species in the environment may cause changes in the chemical functionality of the surface and change the toxic properties of the particles when they are inhaled. Furthermore, metals on the surface of inhalable particles can contribute to their toxicity. Much attention has been given to the presence of iron on the surfaces of inhalable particles in the environment. After particle inhalation, particles are endocytosed by alveolar macrophages in the immune response to foreign matter. They are exposed to hydrogen peroxide in the oxidative burst, which can cause the iron-mediated production of hydroxyl free radicals via the Fenton reaction, causing oxidative stress that leads to inflammation and cell death. The toxicity of particles that contain metals depends on the redox activity and bioavailability of the metals, the causes of thich have not yet been adequately explored. In this thesis, electron paramagnetic spectroscopy showed

  15. Modeling Aquatic Toxicity through Chromatographic Systems.

    Science.gov (United States)

    Fernández-Pumarega, Alejandro; Amézqueta, Susana; Farré, Sandra; Muñoz-Pascual, Laura; Abraham, Michael H; Fuguet, Elisabet; Rosés, Martí

    2017-08-01

    Environmental risk assessment requires information about the toxicity of the growing number of chemical products coming from different origins that can contaminate water and become toxicants to aquatic species or other living beings via the trophic chain. Direct toxicity measurements using sensitive aquatic species can be carried out but they may become expensive and ethically questionable. Literature refers to the use of chromatographic measurements that correlate to the toxic effect of a compound over a specific aquatic species as an alternative to get toxicity information. In this work, we have studied the similarity in the response of the toxicity to different species and we have selected eight representative aquatic species (including tadpoles, fish, water fleas, protozoan, and bacteria) with known nonspecific toxicity to chemical substances. Next, we have selected four chromatographic systems offering good perspectives for surrogation of the eight selected aquatic systems, and thus prediction of toxicity from the chromatographic measurement. Then toxicity has been correlated to the chromatographic retention factor. Satisfactory correlation results have been obtained to emulate toxicity in five of the selected aquatic species through some of the chromatographic systems. Other aquatic species with similar characteristics to these five representative ones could also be emulated by using the same chromatographic systems. The final aim of this study is to model chemical products toxicity to aquatic species by means of chromatographic systems to reduce in vivo testing.

  16. Investigation of the Relationship of Some Antihypertensive Drugs with Oxidant/Antioxidant Parameters and DNA Damage on Rat Uterus Tissue

    OpenAIRE

    Mustafa Talip Sener; Hamit Hakan Alp; Beyzagul Polat; Bunyamin Borekci; Yakup Kumtepe; Nesrin Gursan; Serkan Kumbasar; Suleyman Salman; Halis Suleyman

    2011-01-01

    Background In this study, we investigated the effects of treatment with chronic antihypertensive drugs (clonidine, methyldopa, amlodipine, ramipril and rilmenidine) on oxidant-antioxidant parameters and toxic effects on DNA in rat uterus tissue. In addition, uterus tissues were examined histopathologically. Materials and Methods A total of 36 albino Wistar rats were divided into the following six groups: 0.075 mg/kg clonidine group; 100 mg/kg methyldopa group; 2 mg/kg amlodipine group; 2.5 mg...

  17. L-Ascorbate attenuates methamphetamine neurotoxicity through enhancing the induction of endogenous heme oxygenase-1

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Ya-Ni [Department of Nursing, Hsin Sheng College of Medical Care and Management, Taoyuan, Taiwan (China); Wang, Jiz-Yuh [Department of Neurology, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan (China); Lee, Ching-Tien [Department of Nursing, Hsin Sheng College of Medical Care and Management, Taoyuan, Taiwan (China); Lin, Chih-Hung [Graduate Institute of Medical Sciences and Department of Physiology, College of Medicine, Taipei Medical University, Taipei, Taiwan (China); Lai, Chien-Cheng [Far Eastern Memorial Hospital, Department of Surgery, Taipei, Taiwan (China); Wang, Jia-Yi, E-mail: jywang2010@tmu.edu.tw [Graduate Institute of Medical Sciences and Department of Physiology, College of Medicine, Taipei Medical University, Taipei, Taiwan (China)

    2012-12-01

    Methamphetamine (METH) is a drug of abuse which causes neurotoxicity and increased risk of developing neurodegenerative diseases. We previously found that METH induces heme oxygenase (HO)-1 expression in neurons and glial cells, and this offers partial protection against METH toxicity. In this study, we investigated the effects of L-ascorbate (vitamin C, Vit. C) on METH toxicity and HO-1 expression in neuronal/glial cocultures. Cell viability and damage were evaluated by 3-(4,5-dimethylthianol-2-yl)-2,5 diphenyl tetrazolium bromide (MTT) reduction and lactate dehydrogenase (LDH) release, respectively. Neuronal and glial localization of HO-1 were identified by double immunofluorescence staining. Reactive oxygen species (ROS) production was measured using the fluorochrome 2′,7′-dichlorofluorescin diacetate. HO-1 mRNA and protein expression were examined by RT-qPCR and Western blotting, respectively. Results show that Vit. C induced HO-1 mRNA and protein expressions in time- and concentration-dependent manners. Inhibition of p38 mitogen-activated protein kinase (MAPK) but not extracellular signal-regulated kinase (ERK) significantly blocked induction of HO-1 by Vit. C. HO-1 mRNA and protein expressions were significantly elevated by a combination of Vit. C and METH, compared to either Vit. C or METH alone. Pretreatment with Vit. C enhanced METH-induced HO-1 expression and attenuated METH-induced ROS production and neurotoxicity. Pharmacological inhibition of HO activity abolished suppressive effects of Vit. C on METH-induced ROS production and attenuated neurotoxicity. We conclude that induction of HO-1 expression contributes to the attenuation of METH-induced ROS production and neurotoxicity by Vit. C. We suggest that HO-1 induction by Vit. C may serve as a strategy to alleviate METH neurotoxicity. -- Highlights: ► Besides the anti-oxidant effect, Vit. C also induces HO-1 expression in brain cells. ► Vit. C reduces METH neurotoxicity and ROS production by

  18. L-Ascorbate attenuates methamphetamine neurotoxicity through enhancing the induction of endogenous heme oxygenase-1

    International Nuclear Information System (INIS)

    Huang, Ya-Ni; Wang, Jiz-Yuh; Lee, Ching-Tien; Lin, Chih-Hung; Lai, Chien-Cheng; Wang, Jia-Yi

    2012-01-01

    Methamphetamine (METH) is a drug of abuse which causes neurotoxicity and increased risk of developing neurodegenerative diseases. We previously found that METH induces heme oxygenase (HO)-1 expression in neurons and glial cells, and this offers partial protection against METH toxicity. In this study, we investigated the effects of L-ascorbate (vitamin C, Vit. C) on METH toxicity and HO-1 expression in neuronal/glial cocultures. Cell viability and damage were evaluated by 3-(4,5-dimethylthianol-2-yl)-2,5 diphenyl tetrazolium bromide (MTT) reduction and lactate dehydrogenase (LDH) release, respectively. Neuronal and glial localization of HO-1 were identified by double immunofluorescence staining. Reactive oxygen species (ROS) production was measured using the fluorochrome 2′,7′-dichlorofluorescin diacetate. HO-1 mRNA and protein expression were examined by RT-qPCR and Western blotting, respectively. Results show that Vit. C induced HO-1 mRNA and protein expressions in time- and concentration-dependent manners. Inhibition of p38 mitogen-activated protein kinase (MAPK) but not extracellular signal-regulated kinase (ERK) significantly blocked induction of HO-1 by Vit. C. HO-1 mRNA and protein expressions were significantly elevated by a combination of Vit. C and METH, compared to either Vit. C or METH alone. Pretreatment with Vit. C enhanced METH-induced HO-1 expression and attenuated METH-induced ROS production and neurotoxicity. Pharmacological inhibition of HO activity abolished suppressive effects of Vit. C on METH-induced ROS production and attenuated neurotoxicity. We conclude that induction of HO-1 expression contributes to the attenuation of METH-induced ROS production and neurotoxicity by Vit. C. We suggest that HO-1 induction by Vit. C may serve as a strategy to alleviate METH neurotoxicity. -- Highlights: ► Besides the anti-oxidant effect, Vit. C also induces HO-1 expression in brain cells. ► Vit. C reduces METH neurotoxicity and ROS production by

  19. Photon attenuation properties of some thorium, uranium and plutonium compounds

    Energy Technology Data Exchange (ETDEWEB)

    Singh, V. P.; Badiger, N. M. [Karnatak University, Department of Physics, Dharwad-580003, Karnataka (India); Vega C, H. R., E-mail: kudphyvps@rediffmail.com [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas, Zac. (Mexico)

    2015-10-15

    Mass attenuation coefficients, effective atomic numbers, effective electron densities for nuclear materials; thorium, uranium and plutonium compounds have been studied. The photon attenuation properties for the compounds have been investigated for partial photon interaction processes by photoelectric effect, Compton scattering and pair production. The values of these parameters have been found to change with photon energy and interaction process. The variations of mass attenuation coefficients, effective atomic number and electron density with energy are shown graphically. Moreover, results have shown that these compounds are better shielding and suggesting smaller dimensions. The study would be useful for applications of these materials for gamma ray shielding requirement. (Author)

  20. MNAtoolbox: A Monitored Natural Attenuation Site Screening Program

    Energy Technology Data Exchange (ETDEWEB)

    Borns, David J.; Brady, Patrick V.; Brady, Warren D.; Krupka, Kenneth M.; Spalding, Brian P.; Waters, Robert D.; Zhang, Pengchu

    1999-07-12

    Screening of sites for the potential application and reliance upon monitored natural attenuation (MNA) can be done using MNAtoolbox, a web-based tool for estimating extent of biodegradation, chemical transformation, and dilution. MNAtoolbox uses site-specific input data, where available (default parameters are taken from the literature), to roughly quantify the nature and extent of attenuation at a particular site. Use of MNAtoolbox provides 3 important elements of site evaluation: (1) Identifies likely attenuation pathways, (2) Clearly identifies sites where MNA is inappropriate, and (3) Evaluates data requirements for subsequent reliance on MNA as a sole or partial corrective action.

  1. Dithiobiuret toxicity in the rat

    International Nuclear Information System (INIS)

    Williams, K.D.

    1985-01-01

    Raising the daily dose of dithiobiuret (DTB) in male rats from 0.5 to 1 to 5 mg/kg shortened the latency to the onset of flaccid muscle tone and associated diminished performance in a treadmill test from 7 to 5 to 3 days, respectively. Concomitant with the development of flaccid muscle tone gastrocnemius muscle contractions elicited by high frequency motor nerve stimulation were lower in peak tension and tended to fade more rapidly in DTB-treated rats than in control rats. Remarkably, rats treated with highly daily doses (10-16 mg/kg) of DTB were resistant to the expected development of DTB-induced flaccid muscle tone, and tetanic contractile abnormalities but a corresponding refractoriness to body weight loss, decreased fed and water intake, diuresis, and depression in water balance was not present. This nonselectivity of the refractory responses supported the results of a histopathological study indicating that DTB-induced neuromuscular toxicity was unlikely to be secondary to effect on other organ systems. It is not known whether the ultimate neurotoxin is DTB or a metabolite. In this regard, two pathways for the metabolism of DTB were proposed based on the results of thin-layer chromatography of urine samples from rats treated with either 14 C- or 35 S-DTB. One pathway involved the reversible oxidation of DTB to the disulfide-containing compound thiuret, and the other involved the replacement of a sulfur atom with oxygen to form monothiobiuret. Thiuret, but not monothiobiuret, possessed comparable toxicity to STB. This further suggested that redox cycling between DTB and thiuret could be an important contributing factor to the toxicity of DTB

  2. Lysophospholipase inhibition by organophosphorus toxicants

    International Nuclear Information System (INIS)

    Quistad, Gary B.; Casida, John E.

    2004-01-01

    Lysophospholipases (LysoPLAs) are a large family of enzymes for removing lysophospholipids from cell membranes. Potent inhibitors are needed to define the importance of LysoPLAs as targets for toxicants and potential therapeutics. This study considers organophosphorus (OP) inhibitors with emphasis on mouse brain total LysoPLA activity relative to the mipafox-sensitive neuropathy target esterase (NTE)-LysoPLA recently established as 17% of the total activity and important in the action of OP delayed toxicants. The most potent inhibitors of total LysoPLA in mouse brain are isopropyl dodecylphosphonofluoridate (also for LysoPLA of Vibrio bacteria), ethyl octylphosphonofluoridate (EOPF), and two alkyl-benzodioxaphosphorin 2-oxides (BDPOs)[(S)-octyl and dodecyl] (IC50 2-8 nM). OP inhibitors acting in vitro and in vivo differentiate a more sensitive portion but not a distinct NTE-LysoPLA compared with total LysoPLA activity. For 10 active inhibitors, NTE-LysoPLA is 17-fold more sensitive than total LysoPLA, but structure-activity comparisons give a good correlation (r 2 = 0.94) of IC50 values, suggesting active site structural similarity or identity. In mice 4 h after intraperitoneal treatment with discriminating doses, EOPF, tribufos (a plant defoliant), and dodecanesulfonyl fluoride inhibit 41-57% of the total brain LysoPLA and 85-99% of the NTE-LysoPLA activity. Total LysoPLA as well as NTE-LysoPLA is decreased in activity in Nte +/- -haploinsufficient mice compared to their Nte +/+ littermates. The lysolecithin level of spinal cord but not brain is elevated significantly following EOPF treatment (3 mg/kg), thereby focusing attention on localized rather than general alterations in lysophospholipid metabolism in OP-induced hyperactivity and toxicity

  3. Molecular basis of cadmium toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Nath, R; Prasad, R; Palinal, V K; Chopra, R K

    1984-01-01

    Cadmium has been shown to manifest its toxicity in human and animals by mainly accumulating in almost all of the organs. The kidney is the main target organ where it is concentrated mainly in the cortex. Environmental exposure of cadmium occurs via food, occupational industries, terrestrial and aquatic ecosystem. At molecular level, cadmium interferes with the utilization of essential metals e.g. Ca, Zn, Se, Cr and Fe and deficiencies of these essential metals including protein and vitamins, exaggerate cadmium toxicity, due to its increased absorption through the gut and greater retention in different organs as metallothionein (Cd-Mt). Cadmium transport, across the intestinal and renal brush border membrane vesicles, is carrier mediated and it competes with zinc and calcium. It has been postulated that cadmium shares the same transport system. Cadmium inhibits protein synthesis, carbohydrate metabolism and drug metabolizing enzymes in liver of animals. Chronic environmental exposure of cadmium produces hypertension in experimental animals. Functional changes accompanying cadmium nephropathy include low molecular weight proteinuria which is of tubular origin associated with excess excretion of proteins such as beta 2 microglobulin, metallothionein and high molecular weight proteinuria of glomerular origin (excretion of proteins such as albumin IgG, transferrin etc.). Recent data has shown that metallothionein is more nephrotoxic to animals. Cadmium is also toxic to central nervous system. It causes an alterations of cellular functions in lungs. Cadmium affects both humoral and cell mediated immune response in animals. Cadmium induces metallothionein in liver and kidney but under certain nutritional deficiencies like protein-calorie malnutrition and calcium deficiency, enhanced induction and greater accumulation of cadmium metallothionein has been observed.

  4. Lecithin in mixed micelles attenuates the cytotoxicity of bile salts in Caco-2 cells.

    Science.gov (United States)

    Tan, Ya'nan; Qi, Jianping; Lu, Yi; Hu, Fuqiang; Yin, Zongning; Wu, Wei

    2013-03-01

    This study was designed to investigate the cytotoxicity of bile salt-lecithin mixed micelles on the Caco-2 cell model. Cell viability and proliferation after mixed micelles treatments were evaluated with the MTT assay, and the integrity of Caco-2 cell monolayer was determined by quantitating the transepithelial electrical resistance and the flux of tracer, FITC-dextran 4400. The apoptosis induced by mixed micelles treatments was investigated with the annexin V/PI protocol. The particle size of mixed micelles was all smaller than 100 nm. The mixed micelles with lower than 0.2mM sodium deoxycholate (SDC) had no significant effects on cell viability and proliferation. When the level of SDC was higher than 0.4mM and the lecithin/SDC ratio was lower than 2:1, the mixed micelles caused significant changes in cell viability and proliferation. Furthermore, the mixed micelles affected tight junctions in a composition-dependent manner. Specifically, the tight junctions were transiently opened rather than damaged by the mixed micelles with SDC of between 0.2 and 0.6mM. The mixed micelles with more lecithin also induced less apoptosis. These results demonstrate that relatively higher concentrations of mixed micelles are toxic to Caco-2 cells, while phospholipids can attenuate the toxicity of the bile salts. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

  5. Red Palm Oil Attenuates Lead Acetate Induced Testicular Damage in Adult Male Sprague-Dawley Rats

    Directory of Open Access Journals (Sweden)

    A. I. Jegede

    2015-01-01

    Full Text Available To study the protective effect of Red Palm Oil (RPO on testicular damage induced by administration of lead acetate on male Sprague-Dawley rats, 28 rats divided into four groups of 7 animals each were used. They were administered orally with RPO (1 mL and 2 mL and lead acetate (i.p. 6 mg/kg body weight/day, respectively. Treatment was conducted for 8 weeks, and 24 hrs after the last treatment the rats were sacrificed using cervical dislocation. Sperms collected from epididymis were used for seminal fluid analyses; while the testes sample was used for ROS and oxidative enzyme activities assessment. Statistical analysis was carried out using GraphPad Prism 5.02 statistical analysis package. Administration of lead acetate increased generation of reactive oxygen species (ROS significantly (p<0.05 as evidenced by the elevated value of H2O2 and LPO and decreased GSH level. Also there was reduced epididymal sperm count, poor grade of sperm motility, and lower percentage of normal sperm morphology significantly. Coadministration with RPO, however, has a protective effect against lead toxicity by decreasing H2O2 production, increased GSH level, and increased sperm qualities especially. This shows that RPO has a potential to attenuate the toxic effect of lead on testicular cells preventing possible resultant male infertility.

  6. Attenuation of heavy metal leaching from hazardous wastes by co-disposal of wastes

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Wookeun; Shin, Eung Bai [Hanyang Univ., Ansan (Korea, Republic of); Lee, Kil Chul; Kim, Jae Hyung [National Institute of Environmental Research, Seoul (Korea, Republic of)] [and others

    1996-12-31

    The potential hazard of landfill wastes was previously evaluated by examining the extraction procedures for individual waste, although various wastes were co-disposed of in actual landfills. This paper investigates the reduction of extraction-procedure toxicity by co-disposing various combinations of two wastes. When two wastes are mixed homogeneously, the extraction of heavy metals from the waste mixture is critically affected by the extract pH. Thus, co-disposal wastes will have a resultant pH between the pH values of its constituent. The lower the resultant pH, the lower the concentrations of heavy metals in the extract. When these wastes are extracted sequentially, the latter extracted waste has a stronger influence on the final concentration of heavy metals in the extract. Small-scale lysimeter experiments confirm that when heavy-metal-bearing leachates Generated from hazardous-waste lysimeters are passed through a nonhazardous-waste lysimeter filled with compost, briquette ash, or refuse-incineration ashes, the heavy-metal concentration in the final leachates decreases significantly. Thus, the heavy-metal leaching could be attenuated if a less extraction-procedure-toxic waste were placed at the bottom of a landfill. 3 refs., 4 figs., 5 tabs.

  7. Biodistribution and safety of a live attenuated tetravalent dengue vaccine in the cynomolgus monkey.

    Science.gov (United States)

    Ravel, Guillaume; Mantel, Nathalie; Silvano, Jeremy; Rogue, Alexandra; Guy, Bruno; Jackson, Nicholas; Burdin, Nicolas

    2017-10-13

    The first licensed dengue vaccine is a recombinant, live, attenuated, tetravalent dengue virus vaccine (CYD-TDV; Sanofi Pasteur). This study assessed the biodistribution, shedding, and toxicity of CYD-TDV in a non-human primate model as part of the nonclinical safety assessment program for the vaccine. Cynomolgus monkeys were given one subcutaneous injection of either one human dose (5log 10 CCID 50 /serotype) of CYD-TDV or saline control. Study endpoints included clinical observations, body temperature, body weight, food consumption, clinical pathology, immunogenicity, and post-mortem examinations including histopathology. Viral load, distribution, persistence, and shedding in tissues and body fluids were evaluated by quantitative reverse transcriptase polymerase chain reaction. The subcutaneous administration of CYD-TDV was well tolerated. There were no toxicological findings other than expected minor local reactions at the injection site. A transient low level of CYD-TDV viral RNA was detected in blood and the viral genome was identified primarily at the injection site and in the draining lymph nodes following immunization. These results, together with other data from repeat-dose toxicity and neurovirulence studies, confirm the absence of toxicological concern with CYD-TDV and corroborate clinical study observations. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Metabolism and toxicity of neptunium

    International Nuclear Information System (INIS)

    Nenot, J.C.

    1983-08-01

    The biological behaviour and toxicity of neptunium were studied. Neptunium was administered either intravenously or intramuscularly in rats. In contrast to other transuranium elements the distribution patterns of neptunium in the case of intravenous injection is not dependent on the physico-chemical state. Urinary excretion is high. The distribution after intramuscular injection showed a rather fast migration from the injection site. 237 Neptonium in urine was approximately equal to bone deposit. Neptunium behaviour followed that of alkaline earths rather than that of transplutonium elements

  9. Physiology and toxicity of fluoride

    OpenAIRE

    Dhar Vineet; Bhatnagar Maheep

    2009-01-01

    Fluoride has been described as an essential element needed for normal development and growth of animals and extremely useful for human beings. Fluoride is abundant in the environment and the main source of fluoride to humans is drinking water. It has been proved to be beneficial in recommended doses, and at the same time its toxicity at higher levels has also been well established. Fluoride gets accumulated in hard tissues of the body and has been know to play an important role in mineralizat...

  10. Air toxics research in Finland

    International Nuclear Information System (INIS)

    Hahkala, M.

    1994-01-01

    Air toxics research in Finland has developed rapidly in recent years. Though they have no enormous environmental problems in Finland, the author feels that they have to increase their knowledge of more efficient energy production and control technology. Enormous emission sources are around them, but there are also huge markets for know-how and technology in the energy sector. Two Finnish national research programs will ensure the continuity of the development efforts concerning combustion technology and environmental aspects at both theoretical and practical levels

  11. Copper toxicity in housed lambs

    Energy Technology Data Exchange (ETDEWEB)

    Adamson, A H; Valks, D A; Appleton, M A; Shaw, W B

    1969-09-27

    Copper toxicity among 170 lambs artificially reared indoors at High Mowthorpe NAAS Experimental Husbandry Farm is reported. Although only three lambs were lost it is not unreasonable to suggest that the liver copper levels of the lambs which were slaughtered would have been high and losses could have been much heavier had there been any further copper supplementation. Even a copper level of 20 ppm in lamb concentrates given to lambs reared artificially indoors is dangerous, and intakes of much less than 38 mg per lamb per day can be fatal if given of a prolonged period. 5 references, 1 table.

  12. Telmisartan attenuates diabetes induced depression in rats.

    Science.gov (United States)

    Aswar, Urmila; Chepurwar, Shilpa; Shintre, Sumit; Aswar, Manoj

    2017-04-01

    Role of brain renin angiotensin system (RAS) is well understood and various clinical studies have proposed neuroprotective effects of ARB's. It is also assumed that diabetic depression is associated with activation of brain RAS, HPA axis dysregulation and brain inflammatory events. Therefore, the present study was designed to investigate the antidepressant effect of low dose telmisartan (TMS) in diabetes induced depression (DID) in rats. Diabetes was induced by injecting streptozotocin. After 21days of treatment the rats were subjected to forced swim test (FST). The rats, with increased immobility time, were considered depressed and were treated with vehicle or TMS (0.05mg/kg, po) or metformin (200mg/kg, po) or fluoxetine (20mg/kg, po). A separate group was also maintained to study the combination of metformin and TMS. At the end of 21days of treatments, FST, open field test (OFT) and elevated plus maze (EPM) paradigm were performed. Blood was drawn to estimate serum cortisol, nitric oxide (NO), interleukin-6 (IL-6) and interleukin-1β (IL-1β). Persistent hyperglycemia resulted in depression and anxiety in rats as observed by increased immobility, reduced latency for immobility, reduced open arm entries and time spent. The depressed rats showed a significant rise in serum cortisol, NO, IL-6 and IL-1β (pdepression and anxiety. It also significantly attenuated serum cortisol, NO, IL-6 and IL-1β (pdepressive mood, reduces pro-inflammatory mediators and ameliorates the HPA axis function; thereby providing beneficial effects in DID. Copyright © 2016. Published by Elsevier Urban & Partner Sp. z o.o.

  13. MRI-guided attenuation correction in whole-body PET/MR. Assessment of the effect of bone attenuation

    International Nuclear Information System (INIS)

    Akbarzadeh, A.; Ay, M.R.; Ahmadian, A.; Riahi Alam, N.; Zaidi, H.

    2013-01-01

    Hybrid positron emission tomography (PET)/MRI presents many advantages in comparison with its counterpart PET/CT in terms of improved soft-tissue contrast, decrease in radiation exposure, and truly simultaneous and multi-parametric imaging capabilities. However, the lack of well-established methodology for MR-based attenuation correction is hampering further development and wider acceptance of this technology. We assess the impact of ignoring bone attenuation and using different tissue classes for generation of the attenuation map on the accuracy of attenuation correction of PET data. This work was performed using simulation studies based on the XCAT phantom and clinical input data. For the latter, PET and CT images of patients were used as input for the analytic simulation model using realistic activity distributions where CT-based attenuation correction was utilized as reference for comparison. For both phantom and clinical studies, the reference attenuation map was classified into various numbers of tissue classes to produce three (air, soft tissue and lung), four (air, lungs, soft tissue and cortical bones) and five (air, lungs, soft tissue, cortical bones and spongeous bones) class attenuation maps. The phantom studies demonstrated that ignoring bone increases the relative error by up to 6.8% in the body and up to 31.0% for bony regions. Likewise, the simulated clinical studies showed that the mean relative error reached 15% for lesions located in the body and 30.7% for lesions located in bones, when neglecting bones. These results demonstrate an underestimation of about 30% of tracer uptake when neglecting bone, which in turn imposes substantial loss of quantitative accuracy for PET images produced by hybrid PET/MRI systems. Considering bones in the attenuation map will considerably improve the accuracy of MR-guided attenuation correction in hybrid PET/MR to enable quantitative PET imaging on hybrid PET/MR technologies. (author)

  14. Radiation Attenuation and Stability of ClearView Radiation Shielding TM-A Transparent Liquid High Radiation Shield.

    Science.gov (United States)

    Bakshi, Jayeesh

    2018-04-01

    Radiation exposure is a limiting factor to work in sensitive environments seen in nuclear power and test reactors, medical isotope production facilities, spent fuel handling, etc. The established choice for high radiation shielding is lead (Pb), which is toxic, heavy, and abidance by RoHS. Concrete, leaded (Pb) bricks are used as construction materials in nuclear facilities, vaults, and hot cells for radioisotope production. Existing transparent shielding such as leaded glass provides minimal shielding attenuation in radiotherapy procedures, which in some cases is not sufficient. To make working in radioactive environments more practicable while resolving the lead (Pb) issue, a transparent, lightweight, liquid, and lead-free high radiation shield-ClearView Radiation Shielding-(Radium Incorporated, 463 Dinwiddie Ave, Waynesboro, VA). was developed. This paper presents the motivation for developing ClearView, characterization of certain aspects of its use and performance, and its specific attenuation testing. Gamma attenuation testing was done using a 1.11 × 10 Bq Co source and ANSI/HPS-N 13.11 standard. Transparency with increasing thickness, time stability of liquid state, measurements of physical properties, and performance in freezing temperatures are reported. This paper also presents a comparison of ClearView with existing radiation shields. Excerpts from LaSalle nuclear power plant are included, giving additional validation. Results demonstrated and strengthened the expected performance of ClearView as a radiation shield. Due to the proprietary nature of the work, some information is withheld.

  15. The Toxicity of Depleted Uranium

    Directory of Open Access Journals (Sweden)

    Wayne Briner

    2010-01-01

    Full Text Available Depleted uranium (DU is an emerging environmental pollutant that is introduced into the environment primarily by military activity. While depleted uranium is less radioactive than natural uranium, it still retains all the chemical toxicity associated with the original element. In large doses the kidney is the target organ for the acute chemical toxicity of this metal, producing potentially lethal tubular necrosis. In contrast, chronic low dose exposure to depleted uranium may not produce a clear and defined set of symptoms. Chronic low-dose, or subacute, exposure to depleted uranium alters the appearance of milestones in developing organisms. Adult animals that were exposed to depleted uranium during development display persistent alterations in behavior, even after cessation of depleted uranium exposure. Adult animals exposed to depleted uranium demonstrate altered behaviors and a variety of alterations to brain chemistry. Despite its reduced level of radioactivity evidence continues to accumulate that depleted uranium, if ingested, may pose a radiologic hazard. The current state of knowledge concerning DU is discussed.

  16. A Miniscale Algal Toxicity Test

    DEFF Research Database (Denmark)

    Arensberg, Pia; Hemmingsen, Vicky H.; Nyholm, Niels

    1995-01-01

    A simple miniscale (approx. 1 - 2.5 ml) toxicity test procedure with the freshwater green algaSelenastrum capricornutum is described. The procedure fulfils the validity criteria of the ISO (International Association for Standardization) standard test protocol. Practically identical concentration-...... days to 2 days (minitest as well as larger volume tests) in order to avoid excessive biomass growth. Shortening tests to 2 days appears necessary if light intensity and temperature are near the upper limits of the intervals stated in the ISO standard.......A simple miniscale (approx. 1 - 2.5 ml) toxicity test procedure with the freshwater green algaSelenastrum capricornutum is described. The procedure fulfils the validity criteria of the ISO (International Association for Standardization) standard test protocol. Practically identical concentration......-response curves were obtained with the ISO standard test and the minitest for potassium dichromate and 3,5-dichlorophenol. The minitest is conveniently carried out using 2.5 ml test volume in 20 ml glass scintillation vials, placed on a microplate shaker or on an ordinary shaking table, but smaller containers...

  17. Oral Chromium Exposure and Toxicity

    Science.gov (United States)

    Sun, Hong; Brocato, Jason

    2015-01-01

    Hexavalent chromium [Cr(VI)] is a known carcinogen when inhaled. However, inhalational exposure to Cr(VI) affects only a small portion of the population, mainly by occupational exposures. In contrast, oral exposure to Cr(VI) is widespread and affects many people throughout the globe. In 2008, the National Toxicology Program (NTP) released a 2-year study demonstrating that ingested Cr(VI) was carcinogenic in rats and mice. The effects of Cr(VI) oral exposure is mitigated by reduction in the gut, however a portion evades the reductive detoxification and reaches target tissues. Once Cr(VI) enters the cell, it ultimately gets reduced to Cr(III), which mediates its toxicity via induction of oxidative stress during the reduction while Cr intermediates react with protein and DNA. Cr(III) can form adducts with DNA that may lead to mutations. This review will discuss the potential adverse effects of oral exposure to Cr(VI) by presenting up-to-date human and animal studies, examining the underlying mechanisms that mediate Cr(VI) toxicity, as well as highlighting opportunities for future research. PMID:26231506

  18. Toxic ornamental plants in Venezuela

    Directory of Open Access Journals (Sweden)

    Carlos Varela Romero

    2017-01-01

    Full Text Available The aim of this research was to contribute information on toxic ornamental plants in Venezuela. Information on taxonomy, common names, habit, origin, status, location, propagation and toxicology (part of the plant, effects was compiled from articles, books, catalogs, herbarium collections. A botanical analysis (taxonomy, common names, habit, origin, status, location, propagation and toxicology (part of the plant, effects was performed. The information about plant poisoning cases was requested to SIMET (Pharmacy faculty -UCV. Seventy-eight species were found in 34 families, the most important were: Apocynaceae (10 genera/12 species, Araceae (9/9, Euphorbiaceae (4/10 and Solanaceae (5/6. Genus Euphorbia was the most species rich. Most species were exotic species (79.5% and shrubs (32.1%. The entire plant (35 and latex (19 were the most toxic parts and the most frequent accidental ingestion (61.5%. Twenty cases were reported between 2009-2013, of which 80% were minors, female and urban areas. There is very little information published in Hispanic American countries

  19. Male-mediated developmental toxicity

    Directory of Open Access Journals (Sweden)

    Diana Anderson

    2014-02-01

    Full Text Available Male-mediated developmental toxicity has been of concern for many years. The public became aware of male-mediated developmental toxicity in the early 1990s when it was reported that men working at Sellafield might be causing leukemia in their children. Human and animal studies have contributed to our current understanding of male-mediated effects. Animal studies in the 1980s and 1990s suggested that genetic damage after radiation and chemical exposure might be transmitted to offspring. With the increasing understanding that there is histone retention and modification, protamine incorporation into the chromatin and DNA methylation in mature sperm and that spermatozoal RNA transcripts can play important roles in the epigenetic state of sperm, heritable studies began to be viewed differently. Recent reports using molecular approaches have demonstrated that DNA damage can be transmitted to babies from smoking fathers, and expanded simple tandem repeats minisatellite mutations were found in the germline of fathers who were exposed to radiation from the Chernobyl nuclear power plant disaster. In epidemiological studies, it is possible to clarify whether damage is transmitted to the sons after exposure of the fathers. Paternally transmitted damage to the offspring is now recognized as a complex issue with genetic as well as epigenetic components.

  20. Hypothermia reduces sulphur mustard toxicity

    International Nuclear Information System (INIS)

    Mi Lei; Gong Wenrong; Nelson, Peggy; Martin, Leanne; Sawyer, Thomas W.

    2003-01-01

    The effect of temperature on the development of sulphur mustard (HD)-induced toxicity was investigated in first passage cultures of human skin keratinocytes and on hairless guinea pig skin. When cells exposed to HD were incubated at 37 deg. C, a concentration-dependent decline in viability was observed that was maximal by 2 days. In contrast, no significant HD-induced toxicity was evident up to 4 days posttreatment when the cells were incubated at 25 deg. C. However, these protective effects were lost by 24 h when the cells were switched back to 37 deg. C. The protective effects of hypothermia were also demonstrated when apoptotic endpoints were examined. The HD concentration-dependent induction of fragmented DNA (as quantitated using soluble DNA and the TUNEL reaction), morphology, and p53 expression were all significantly depressed when cell cultures were incubated at 25 deg. C compared to 37 deg. C. When animals were exposed to HD vapour for 2, 4, and 6 min and left at room temperature, lesions were produced whose severity was dependent on exposure time and that were maximal by 72 h posttreatment. Moderate cooling (5-10 deg. C) of HD exposure sites posttreatment (4-6 h) significantly reduced the severity of the resultant lesions. However, in contrast to the in vitro results, these effects were permanent. It appears that the early and noninvasive act of cooling HD-exposed skin may provide a facile means of reducing the severity of HD-induced cutaneous lesions

  1. Toxicity of fluoride to aquatic species and evaluation of toxicity modifying factors.

    Science.gov (United States)

    Pearcy, Krysta; Elphick, James; Burnett-Seidel, Charlene

    2015-07-01

    The present study was performed to investigate the toxicity of fluoride to a variety of freshwater aquatic organisms and to establish whether water quality variables contribute substantively to modifying its toxicity. Water hardness, chloride, and alkalinity were tested as possible toxicity modifying factors for fluoride using acute toxicity tests with Hyalella azteca and Oncorhynchus mykiss. Chloride appeared to be the major toxicity modifying factor for fluoride in these acute toxicity tests. The chronic toxicity of fluoride was evaluated with a variety of species, including 3 fish (Pimephales promelas, O. mykiss, and Salvelinus namaycush), 3 invertebrates (Ceriodaphnia dubia, H. azteca, and Chironomus dilutus), 1 plant (Lemna minor), and 1 alga (Pseudokirchneriella subcapitata). Hyalella azteca was the most sensitive species overall, and O. mykiss was the most sensitive species of fish. The role of chloride as a toxicity modifying factor was inconsistent between species in the chronic toxicity tests. © 2015 SETAC.

  2. Urtica dioica attenuate effect of Doxorobicin‐Induced changes on sperm parameters in the mice

    Directory of Open Access Journals (Sweden)

    Zahra Baninameh

    2016-11-01

    Full Text Available Doxorubicin (DXR is used as an antitumor agent for the treatment of human neoplasm. The use of DXR has adverse effect on reproductive system including testicular toxicity and alteration in semen quality. The aim of this study was to evaluate the protective effects of Urtica dioica against Doxorobicin‐Induced changes on sperm parameters. 24 male mice were randomly divided into 4 groups. Control group received normal saline solution throughout the course of the study. Urtica dioica (UD control group, received UD (100 mg/kg body weight thrice in a week and DOX (3 mg/kg body weight once in a week injected intraperitoneally in Doxorubicin (DXR control group and Urtica dioica- Doxorubicin (UD-DXR group, received Urtica dioica (100 mg/kg body weight three times in a week and DOX (3 mg/kg body weight once in a week through the route for a period of 2 weeks. At the end of experimental period, all animal were sacrificed by cervical dislocation, their epididymes were removed and sperm analysis were done. In mice with DXR administration, epididymal sperm motility, progressive motility, sperm count and viability significantly decrease while sperm cells with abnormal morphology significantly increase when compared with control groups. Co-treatment with UD attenuate toxicity effect of DXR and improve sperm parameters. Results of our study showed that UD diminished DXR-induced testicular toxicity and improve semen parameters, thus suggesting its co-administration as a protective agent during doxorubicin treatment. Further studies should be aimed to determine protective effect of UD against chemotherapeutic agents such as DXR.

  3. Analytical inversion formula for uniformly attenuated fan-beam projections

    International Nuclear Information System (INIS)

    Weng, Y.; Zeng, G.L.; Gullberg, G.T.

    1997-01-01

    In deriving algorithms to reconstruct single photon emission computed tomography (SPECT) projection data, it is important that the algorithm compensates for photon attenuation in order to obtain quantitative reconstruction results. A convolution backprojection algorithm was derived by Tretiak and Metz to reconstruct two-dimensional (2-D) transaxial slices from uniformly attenuated parallel-beam projections. Using transformation of coordinates, this algorithm can be modified to obtain a formulation useful to reconstruct uniformly attenuated fan-beam projections. Unlike that for parallel-beam projections, this formulation does not produce a filtered backprojection reconstruction algorithm but instead has a formulation that is an inverse integral operator with a spatially varying kernel. This algorithm thus requires more computation time than does the filtered backprojection reconstruction algorithm for the uniformly attenuated parallel-beam case. However, the fan-beam reconstructions demonstrate the same image quality as that of parallel-beam reconstructions

  4. Magnitude corrections for attenuation in the upper mantle

    International Nuclear Information System (INIS)

    Anon.

    1978-01-01

    Since 1969, a consistent discrepancy in seismic magnitudes of nuclear detonations at NTS compared with magnitudes of detonations elsewhere in the world has been observed. This discrepancy can be explained in terms of a relatively high seismic attenuation for compressional waves in the upper mantle beneath the NTS and in certain other locations. A correction has been developed for this attenuation based on a relationship between the velocity of compressional waves at the top of the earth's mantle (just beneath the Mohorovicic discontinuity) and the seismic attenuation further down in the upper mantle. Our new definition of body-wave magnitude includes corrections for attenuation in the upper mantle at both ends of the teleseismic body-wave path. These corrections bring the NTS oservations into line with measurements of foreign events, and enable one to make more reliable estimates of yields of underground nuclear explosions, wherever the explosion occurs

  5. Validity of the CT to attenuation coefficient map conversion methods

    International Nuclear Information System (INIS)

    Faghihi, R.; Ahangari Shahdehi, R.; Fazilat Moadeli, M.

    2004-01-01

    The most important commercialized methods of attenuation correction in SPECT are based on attenuation coefficient map from a transmission imaging method. The transmission imaging system can be the linear source of radioelement or a X-ray CT system. The image of transmission imaging system is not useful unless to replacement of the attenuation coefficient or CT number with the attenuation coefficient in SPECT energy. In this paper we essay to evaluate the validity and estimate the error of the most used method of this transformation. The final result shows that the methods which use a linear or multi-linear curve accept a error in their estimation. The value of mA is not important but the patient thickness is very important and it can introduce a error more than 10 percent in the final result

  6. The use of microperforated plates to attenuate cavity resonances

    DEFF Research Database (Denmark)

    Fenech, Benjamin; Keith, Graeme; Jacobsen, Finn

    2006-01-01

    The use of microperforated plates to introduce damping in a closed cavity is examined. By placing a microperforated plate well inside the cavity instead of near a wall as traditionally done in room acoustics, high attenuation can be obtained for specific acoustic modes, compared with the lower...... attenuation that can be obtained in a broad frequency range with the conventional position of the plate. An analytical method for predicting the attenuation is presented. The method involves finding complex eigenvalues and eigenfunctions for the modified cavity and makes it possible to predict Green......'s functions. The results, which are validated experimentally, show that a microperforated plate can provide substantial attenuation of modes in a cavity. One possible application of these findings is the treatment of boiler tones in heat-exchanger cavities....

  7. Multi-resolution inversion algorithm for the attenuated radon transform

    KAUST Repository

    Barbano, Paolo Emilio; Fokas, Athanasios S.

    2011-01-01

    We present a FAST implementation of the Inverse Attenuated Radon Transform which incorporates accurate collimator response, as well as artifact rejection due to statistical noise and data corruption. This new reconstruction procedure is performed

  8. Numerical Speadsheet Modeling of Natural Attenuation for Groundwater Contaminant Plumes

    National Research Council Canada - National Science Library

    Twesme, Troy

    1999-01-01

    .... The model was used to evaluate natural attenuation for removal of a trichloroethylene (TCE) plume from a surficial aquifer containing three regions with distinctly different processes for degradation of TCE...

  9. Practical method of breast attenuation correction for cardiac SPECT

    International Nuclear Information System (INIS)

    Oliveira, Anderson de; Nogueira, Tindyua; Gutterres, Ricardo Fraga; Megueriam, Berdj Aram; Santos, Goncalo Rodrigues dos

    2007-01-01

    The breast attenuation effects on SPECT (Single Photon Emission Tomography) myocardium perfusion procedures have been lately scope of continuous inquiry. The requested attenuation correction factors are usually achieved by transmission analysis, making up the exposure of a standard external source to the SPECT, as a routine step. However, its high cost makes this methodology not fully available to the most of nuclear medicines services in Brazil and abroad. To overcome the problem, a new trend is presented in this work, implementing computational models to balance the breast attenuation effects on the left ventricle anterior wall, during myocardium perfusion scintigraphy procedures with SPECT. A neural network was put on in order to provide the attenuation correction indexes, based upon the following patients individual biotypes features: mass, age, height, chest and breast thicknesses, heart size, as well as the imparted activity intake levels. (author)

  10. Practical method of breast attenuation correction for cardiac SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Anderson de; Nogueira, Tindyua; Gutterres, Ricardo Fraga [Comissao Nacional de Energia Nuclear (CNEN), Rio de Janeiro, RJ (Brazil). Coordenacao Geral de Instalacoes Medicas e Industriais (CGMI)]. E-mails: anderson@cnen.gov.br; tnogueira@cnen.gov.br; rguterre@cnen.gov.br; Megueriam, Berdj Aram [Instituto Nacional do Cancer (INCA), Rio de Janeiro, RJ (Brazil)]. E-mail: megueriam@hotmail.com; Santos, Goncalo Rodrigues dos [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)]. E-mail: goncalo@cnen.gov.br

    2007-07-01

    The breast attenuation effects on SPECT (Single Photon Emission Tomography) myocardium perfusion procedures have been lately scope of continuous inquiry. The requested attenuation correction factors are usually achieved by transmission analysis, making up the exposure of a standard external source to the SPECT, as a routine step. However, its high cost makes this methodology not fully available to the most of nuclear medicines services in Brazil and abroad. To overcome the problem, a new trend is presented in this work, implementing computational models to balance the breast attenuation effects on the left ventricle anterior wall, during myocardium perfusion scintigraphy procedures with SPECT. A neural network was put on in order to provide the attenuation correction indexes, based upon the following patients individual biotypes features: mass, age, height, chest and breast thicknesses, heart size, as well as the imparted activity intake levels. (author)

  11. 2 original article non-attenuation of highly pathogenic avian

    African Journals Online (AJOL)

    Dr Oboro VO

    AFRICAN JOURNAL OF CLINICAL AND EXPERIMENTAL MICROBIOLOGY JANUARY 2010. ISBN 1595-689X ... NON-ATTENUATION OF HIGHLY PATHOGENIC AVIAN INFLUENZA. H5N1 BY .... Diagnostic PCR was conducted to determine ...

  12. Gamma ray attenuation coefficient measurement for neutron-absorbent materials

    International Nuclear Information System (INIS)

    Jalali, Majid; Mohammadi, Ali

    2008-01-01

    The compounds Na 2 B 4 O 7 , H 3 BO 3 , CdCl 2 and NaCl and their solutions attenuate gamma rays in addition to neutron absorption. These compounds are widely used in the shielding of neutron sources, reactor control and neutron converters. Mass attenuation coefficients of gamma related to the four compounds aforementioned, in energies 662, 778.9, 867.38, 964.1, 1085.9, 1173, 1212.9, 1299.1,1332 and 1408 keV, have been determined by the γ rays transmission method in a good geometry setup; also, these coefficients were calculated by MCNP code. A comparison between experiments, simulations and Xcom code has shown that the study has potential application for determining the attenuation coefficient of various compound materials. Experiment and computation show that H 3 BO 3 with the lowest average Z has the highest gamma ray attenuation coefficient among the aforementioned compounds

  13. Natural Attenuation of the Persistent Chemical Warfare Agent ...

    Science.gov (United States)

    Report This project studied the influence of temperature on the natural attenuation of VX from five types of porous/permeable materials: unsealed concrete, plywood, rubber escalator handrail, high density polyethylene (HDPE) plastic, and acoustic ceiling tile.

  14. An acoustic eikonal equation for attenuating VTI media

    KAUST Repository

    Hao, Qi; Alkhalifah, Tariq Ali

    2016-01-01

    We present an acoustic eikonal equation governing the complex-valued travel time of P-waves in attenuating, transversely isotropic media with a vertical symmetry axis (VTI). This equation is based on the assumption that the Pwave complex

  15. An acoustic eikonal equation for attenuating orthorhombic media

    KAUST Repository

    Hao, Qi; Alkhalifah, Tariq Ali

    2017-01-01

    solve the eikonal equation using a combination of the perturbation method and Shanks transform. For a horizontal attenuating orthorhombic layer, both the real and imaginary part of the complex-valued reflection traveltime have nonhyperbolic behaviors

  16. Does a concomitant exposure to lead influence unfavorably the naphthalene subchronic toxicity and toxicokinetics?

    Science.gov (United States)

    Katsnelson, Boris A; Minigaliyeva, Ilzira A; Degtyareva, Tamara D; Privalova, Larisa I; Beresneva, Tatyana A

    2014-01-01

    Rats were given 20 times during 40 d either naphthalene per gavage or the same and lead acetate intraperitoneally in single doses corresponding to 5% of the respective 50% lethal doses. The concomitant exposure to lead not only added some typical indicators of lead toxicity to the moderate naphthalene intoxication picture but also exaggerated some less specific indices for intoxication. However, a number of such indices testified to attenuation of naphthalene's adverse effects under the impact of lead. Lead also lowered urinary excretion of both total and conjugated naphthalene, while the free- to total naphthalene ratio in urine sharply increased. These results corroborate implicitly the initial hypothesis that lead, being an inhibitor of cytochrome P450, hinders phase I of the naphthalene biotransformation and, thus, the formation of derivates which can be more toxic but are capable of entering into reactions of conjugation with resulting detoxication and elimination of naphthalene from the body. © 2013 SETAC.

  17. Dose reduction using a dynamic, piecewise-linear attenuator

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, Scott S., E-mail: sshsieh@stanford.edu [Department of Radiology, Stanford University, Stanford, California 94305 and Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States); Fleischmann, Dominik [Department of Radiology, Stanford University, Stanford, California 94305 (United States); Pelc, Norbert J. [Department of Radiology, Stanford University, Stanford, California 94305 and Department of Bioengineering, Stanford University, Stanford, California 94305 (United States)

    2014-02-15

    Purpose: The authors recently proposed a dynamic, prepatient x-ray attenuator capable of producing a piecewise-linear attenuation profile customized to each patient and viewing angle. This attenuator was intended to reduce scatter-to-primary ratio (SPR), dynamic range, and dose by redistributing flux. In this work the authors tested the ability of the attenuator to reduce dose and SPR in simulations. Methods: The authors selected four clinical applications, including routine full field-of-view scans of the thorax and abdomen, and targeted reconstruction tasks for an abdominal aortic aneurysm and the pancreas. Raw data were estimated by forward projection of the image volume datasets. The dynamic attenuator was controlled to reduce dose while maintaining peak variance by solving a convex optimization problem, assuminga priori knowledge of the patient anatomy. In targeted reconstruction tasks, the noise in specific regions was given increased weighting. A system with a standard attenuator (or “bowtie filter”) was used as a reference, and used either convex optimized tube current modulation (TCM) or a standard TCM heuristic. The noise of the scan was determined analytically while the dose was estimated using Monte Carlo simulations. Scatter was also estimated using Monte Carlo simulations. The sensitivity of the dynamic attenuator to patient centering was also examined by shifting the abdomen in 2 cm intervals. Results: Compared to a reference system with optimized TCM, use of the dynamic attenuator reduced dose by about 30% in routine scans and 50% in targeted scans. Compared to the TCM heuristics which are typically used withouta priori knowledge, the dose reduction is about 50% for routine scans. The dynamic attenuator gives the ability to redistribute noise and variance and produces more uniform noise profiles than systems with a conventional bowtie filter. The SPR was also modestly reduced by 10% in the thorax and 24% in the abdomen. Imaging with the dynamic

  18. Impact of Scattering Model on Disdrometer Derived Attenuation Scaling

    Science.gov (United States)

    Zemba, Michael; Luini, Lorenzo; Nessel, James; Riva, Carlo (Compiler)

    2016-01-01

    NASA Glenn Research Center (GRC), the Air Force Research Laboratory (AFRL), and the Politecnico di Milano (POLIMI) are currently entering the third year of a joint propagation study in Milan, Italy utilizing the 20 and 40 GHz beacons of the Alphasat TDP5 Aldo Paraboni scientific payload. The Ka- and Q-band beacon receivers were installed at the POLIMI campus in June of 2014 and provide direct measurements of signal attenuation at each frequency. Collocated weather instrumentation provides concurrent measurement of atmospheric conditions at the receiver; included among these weather instruments is a Thies Clima Laser Precipitation Monitor (optical disdrometer) which records droplet size distributions (DSD) and droplet velocity distributions (DVD) during precipitation events. This information can be used to derive the specific attenuation at frequencies of interest and thereby scale measured attenuation data from one frequency to another. Given the ability to both predict the 40 GHz attenuation from the disdrometer and the 20 GHz timeseries as well as to directly measure the 40 GHz attenuation with the beacon receiver, the Milan terminal is uniquely able to assess these scaling techniques and refine the methods used to infer attenuation from disdrometer data.In order to derive specific attenuation from the DSD, the forward scattering coefficient must be computed. In previous work, this has been done using the Mie scattering model, however, this assumes a spherical droplet shape. The primary goal of this analysis is to assess the impact of the scattering model and droplet shape on disdrometer derived attenuation predictions by comparing the use of the Mie scattering model to the use of the T-matrix method, which does not assume a spherical droplet. In particular, this paper will investigate the impact of these two scattering approaches on the error of the resulting predictions as well as on the relationship between prediction error and rain rate.

  19. Wave attenuation across a tidal marsh in San Francisco Bay

    Science.gov (United States)

    Foster-Martinez, Madeline R.; Lacy, Jessica; Ferner, Matthew C.; Variano, Evan A.

    2018-01-01

    Wave attenuation is a central process in the mechanics of a healthy salt marsh. Understanding how wave attenuation varies with vegetation and hydrodynamic conditions informs models of other marsh processes that are a function of wave energy (e.g. sediment transport) and allows for the incorporation of marshes into coastal protection plans. Here, we examine the evolution of wave height across a tidal salt marsh in San Francisco Bay. Instruments were deployed along a cross-shore transect, starting on the mudflat and crossing through zones dominated by Spartina foliosa and Salicornia pacifica. This dataset is the first to quantify wave attenuation for these vegetation species, which are abundant in the intertidal zone of California estuaries. Measurements were collected in the summer and winter to assess seasonal variation in wave attenuation. Calculated drag coefficients of S. foliosa and S. pacifica were similar, indicating equal amounts of vegetation would lead to similar energy dissipation; however, S. pacifica has much greater biomass close to the bed (<20 cm) and retains biomass throughout the year, and therefore, it causes more total attenuation. S. foliosa dies back in the winter, and waves often grow across this section of the marsh. For both vegetation types, attenuation was greatest for low water depths, when the vegetation was emergent. For both seasons, attenuation rates across S. pacifica were the highest and were greater than published attenuation rates across similar (Spartina alterniflora) salt marshes for the comparable depths. These results can inform designs for marsh restorations and management plans in San Francisco Bay and other estuaries containing these species.

  20. Characterizing X-ray Attenuation of Containerized Cargo

    Energy Technology Data Exchange (ETDEWEB)

    Birrer, N. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Divin, C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Glenn, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Martz, H. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Wang, G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-08-02

    X-ray inspection systems can be used to detect radiological and nuclear threats in imported cargo. In order to better understand performance of these systems, the attenuation characteristics of imported cargo need to be determined. This project focused on developing image processing algorithms for segmenting cargo and using x-ray attenuation to quantify equivalent steel thickness to determine cargo density. These algorithms were applied to over 450 cargo radiographs. The results are summarized in this report.

  1. Nuclear equipment to determine soil and water mass attenuation coefficients

    International Nuclear Information System (INIS)

    Zucchi, O.L.A.D.; Nascimento Filho, V.F. do

    1984-01-01

    The feasibility of substituting the monochannel gamma spectrometer, traditionally used in the gamma ray attenuation technique, for a less sophisticated and less expensive system of integral counting is studied. The proposed system can be operated by a non-specialized person. Three detection systems were used in the determination of the mass attenuation coefficients for different types of soil and for water. (M.A.C.) [pt

  2. Patient position alters attenuation effects in multipinhole cardiac SPECT.

    Science.gov (United States)

    Timmins, Rachel; Ruddy, Terrence D; Wells, R Glenn

    2015-03-01

    Dedicated cardiac cameras offer improved sensitivity over conventional SPECT cameras. Sensitivity gains are obtained by large numbers of detectors and novel collimator arrangements such as an array of multiple pinholes that focus on the heart. Pinholes lead to variable amounts of attenuation as a source is moved within the camera field of view. This study evaluated the effects of this variable attenuation on myocardial SPECT images. Computer simulations were performed for a set of nine point sources distributed in the left ventricular wall (LV). Sources were placed at the location of the heart in both an anthropomorphic and a water-cylinder computer phantom. Sources were translated in x, y, and z by up to 5 cm from the center. Projections were simulated with and without attenuation and the changes in attenuation were compared. A LV with an inferior wall defect was also simulated in both phantoms over the same range of positions. Real camera data were acquired on a Discovery NM530c camera (GE Healthcare, Haifa, Israel) for five min in list-mode using an anthropomorphic phantom (DataSpectrum, Durham, NC) with 100 MBq of Tc-99m in the LV. Images were taken over the same range of positions as the simulations and were compared based on the summed perfusion score (SPS), defect width, and apparent defect uptake for each position. Point sources in the water phantom showed absolute changes in attenuation of ≤8% over the range of positions and relative changes of ≤5% compared to the apex. In the anthropomorphic computer simulations, absolute change increased to 20%. The changes in relative attenuation caused a change in SPS of position-dependent changes were removed with attenuation correction. Translation of a source relative to a multipinhole camera caused only small changes in homogeneous phantoms with SPS changing position-dependent changes in attenuation.

  3. Bulk sample self-attenuation correction by transmission measurement

    International Nuclear Information System (INIS)

    Parker, J.L.; Reilly, T.D.

    1976-01-01

    Various methods used in either finding or avoiding the attenuation correction in the passive γ-ray assay of bulk samples are reviewed. Detailed consideration is given to the transmission method, which involves experimental determination of the sample linear attenuation coefficient by measuring the transmission through the sample of a beam of gamma rays from an external source. The method was applied to box- and cylindrically-shaped samples

  4. Adaptive attenuation of aliased ground roll using the shearlet transform

    Science.gov (United States)

    Hosseini, Seyed Abolfazl; Javaherian, Abdolrahim; Hassani, Hossien; Torabi, Siyavash; Sadri, Maryam

    2015-01-01

    Attenuation of ground roll is an essential step in seismic data processing. Spatial aliasing of the ground roll may cause the overlap of the ground roll with reflections in the f-k domain. The shearlet transform is a directional and multidimensional transform that separates the events with different dips and generates subimages in different scales and directions. In this study, the shearlet transform was used adaptively to attenuate aliased and non-aliased ground roll. After defining a filtering zone, an input shot record is divided into segments. Each segment overlaps adjacent segments. To apply the shearlet transform on each segment, the subimages containing aliased and non-aliased ground roll, the locations of these events on each subimage are selected adaptively. Based on these locations, mute is applied on the selected subimages. The filtered segments are merged together, using the Hanning function, after applying the inverse shearlet transform. This adaptive process of ground roll attenuation was tested on synthetic data, and field shot records from west of Iran. Analysis of the results using the f-k spectra revealed that the non-aliased and most of the aliased ground roll were attenuated using the proposed adaptive attenuation procedure. Also, we applied this method on shot records of a 2D land survey, and the data sets before and after ground roll attenuation were stacked and compared. The stacked section after ground roll attenuation contained less linear ground roll noise and more continuous reflections in comparison with the stacked section before the ground roll attenuation. The proposed method has some drawbacks such as more run time in comparison with traditional methods such as f-k filtering and reduced performance when the dip and frequency content of aliased ground roll are the same as those of the reflections.

  5. Broad beam X-rays attenuation in silicum glass

    International Nuclear Information System (INIS)

    Risticj, Dj.; Vukovicj, S.; Markovicj, P.

    1987-01-01

    Using broad beam geometry the attenuation for domestic silicum glass have been studied for constant X-ray potentials from 50 to 150 kV. The density of the silicium glass was 2,5x10 3 kg/m 3 . From the attenuation curves the half value layers were obtained. The use of this glass as the biological shield is pointed out. (author). 2 refs.; 2 tabs.; 2 figs

  6. Transcranial Alternating Current Stimulation Attenuates Neuronal Adaptation.

    Science.gov (United States)

    Kar, Kohitij; Duijnhouwer, Jacob; Krekelberg, Bart

    2017-03-01

    We previously showed that brief application of 2 mA (peak-to-peak) transcranial currents alternating at 10 Hz significantly reduces motion adaptation in humans. This is but one of many behavioral studies showing that weak currents applied to the scalp modulate neural processing. Transcranial stimulation has been shown to improve perception, learning, and a range of clinical symptoms. Few studies, however, have measured the neural consequences of transcranial current stimulation. We capitalized on the strong link between motion perception and neural activity in the middle temporal (MT) area of the macaque monkey to study the neural mechanisms that underlie the behavioral consequences of transcranial alternating current stimulation. First, we observed that 2 mA currents generated substantial intracranial fields, which were much stronger in the stimulated hemisphere (0.12 V/m) than on the opposite side of the brain (0.03 V/m). Second, we found that brief application of transcranial alternating current stimulation at 10 Hz reduced spike-frequency adaptation of MT neurons and led to a broadband increase in the power spectrum of local field potentials. Together, these findings provide a direct demonstration that weak electric fields applied to the scalp significantly affect neural processing in the primate brain and that this includes a hitherto unknown mechanism that attenuates sensory adaptation. SIGNIFICANCE STATEMENT Transcranial stimulation has been claimed to improve perception, learning, and a range of clinical symptoms. Little is known, however, how transcranial current stimulation generates such effects, and the search for better stimulation protocols proceeds largely by trial and error. We investigated, for the first time, the neural consequences of stimulation in the monkey brain. We found that even brief application of alternating current stimulation reduced the effects of adaptation on single-neuron firing rates and local field potentials; this mechanistic

  7. Earth-Space Link Attenuation Estimation via Ground Radar Kdp

    Science.gov (United States)

    Bolen, Steven M.; Benjamin, Andrew L.; Chandrasekar, V.

    2003-01-01

    A method of predicting attenuation on microwave Earth/spacecraft communication links, over wide areas and under various atmospheric conditions, has been developed. In the area around the ground station locations, a nearly horizontally aimed polarimetric S-band ground radar measures the specific differential phase (Kdp) along the Earth-space path. The specific attenuation along a path of interest is then computed by use of a theoretical model of the relationship between the measured S-band specific differential phase and the specific attenuation at the frequency to be used on the communication link. The model includes effects of rain, wet ice, and other forms of precipitation. The attenuation on the path of interest is then computed by integrating the specific attenuation over the length of the path. This method can be used to determine statistics of signal degradation on Earth/spacecraft communication links. It can also be used to obtain real-time estimates of attenuation along multiple Earth/spacecraft links that are parts of a communication network operating within the radar coverage area, thereby enabling better management of the network through appropriate dynamic routing along the best combination of links.

  8. Mapping Pn amplitude spreading and attenuation in Asia

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Xiaoning [Los Alamos National Laboratory; Phillips, William S [Los Alamos National Laboratory; Stead, Richard J [Los Alamos National Laboratory

    2010-12-06

    Pn travels most of its path in the mantle lid. Mapping the lateral variation of Pn amplitude attenuation sheds light on material properties and dynamics of the uppermost region of the mantle. Pn amplitude variation depends on the wavefront geometric spreading as well as material attenuation. We investigated Pn geometric spreading, which is much more complex than a traditionally assumed power-law spreading model, using both synthetic and observed amplitude data collected in Asia. We derived a new Pn spreading model based on the formulation that was proposed previously to account for the spherical shape of the Earth (Yang et. al., BSSA, 2007). New parameters derived for the spreading model provide much better correction for Pn amplitudes in terms of residual behavior. Because we used observed Pn amplitudes to construct the model, the model incorporates not only the effect of the Earth's spherical shape, but also the effect of potential upper-mantle velocity gradients in the region. Using the new spreading model, we corrected Pn amplitudes measured at 1, 2, 4 and 6 Hz and conducted attenuation tomography. The resulting Pn attenuation model correlates well with the regional geology. We see high attenuation in regions such as northern Tibetan Plateau and the western Pacific subduction zone, and low attenuation for stable blocks such as Sichuan and Tarim basins.

  9. An attenuation correction method for PET/CT images

    International Nuclear Information System (INIS)

    Ue, Hidenori; Yamazaki, Tomohiro; Haneishi, Hideaki

    2006-01-01

    In PET/CT systems, accurate attenuation correction can be achieved by creating an attenuation map from an X-ray CT image. On the other hand, respiratory-gated PET acquisition is an effective method for avoiding motion blurring of the thoracic and abdominal organs caused by respiratory motion. In PET/CT systems employing respiratory-gated PET, using an X-ray CT image acquired during breath-holding for attenuation correction may have a large effect on the voxel values, especially in regions with substantial respiratory motion. In this report, we propose an attenuation correction method in which, as the first step, a set of respiratory-gated PET images is reconstructed without attenuation correction, as the second step, the motion of each phase PET image from the PET image in the same phase as the CT acquisition timing is estimated by the previously proposed method, as the third step, the CT image corresponding to each respiratory phase is generated from the original CT image by deformation according to the motion vector maps, and as the final step, attenuation correction using these CT images and reconstruction are performed. The effectiveness of the proposed method was evaluated using 4D-NCAT phantoms, and good stability of the voxel values near the diaphragm was observed. (author)

  10. A promising hybrid approach to SPECT attenuation correction

    International Nuclear Information System (INIS)

    Lewis, N.H.; Faber, T.L.; Corbett, J.R.; Stokely, E.M.

    1984-01-01

    Most methods for attenuation compensation in SPECT either rely on the assumption of uniform attenuation, or use slow iteration to achieve accuracy. However, hybrid methods that combine iteration with simple multiplicative correction can accommodate nonuniform attenuation, and such methods converge faster than other iterative techniques. The authors evaluated two such methods, which differ in use of a damping factor to control convergence. Both uniform and nonuniform attenuation were modeled, using simulated and phantom data for a rotating gamma camera. For simulations done with 360 0 data and the correct attenuation map, activity levels were reconstructed to within 5% of the correct values after one iteration. Using 180 0 data, reconstructed levels in regions representing lesion and background were within 5% of the correct values in three iterations; however, further iterations were needed to eliminate the characteristic streak artifacts. The damping factor had little effect on 360 0 reconstruction, but was needed for convergence with 180 0 data. For both cold- and hot-lesion models, image contrast was better from the hybrid methods than from the simpler geometric-mean corrector. Results from the hybrid methods were comparable to those obtained using the conjugate-gradient iterative method, but required 50-100% less reconstruction time. The relative speed of the hybrid methods, and their accuracy in reconstructing photon activity in the presence of nonuniform attenuation, make them promising tools for quantitative SPECT reconstruction

  11. Interaction between Ammonium Toxicity and Green Tide Development Over Seagrass Meadows: A Laboratory Study.

    Directory of Open Access Journals (Sweden)

    Francisco Moreno-Marín

    Full Text Available Eutrophication affects seagrasses negatively by increasing light attenuation through stimulation of biomass of fast-growing, bloom-forming algae and because high concentrations of ammonium in the water can be toxic to higher plants. We hypothesized nevertheless, that moderate amounts of nitrophilic macroalgae that coexists with seagrasses under eutrophic conditions, can alleviate the harmful effects of eutrophication on seagrasses by reducing ammonium concentrations in the seawater to non-toxic levels because such algae have a very large capacity to take up inorganic nutrients. We studied therefore how combinations of different ammonium concentrations (0, 25 and 50 μM and different standing stocks of macroalgae (i.e. 0, 1 and 6 layers of Ulva sp. affected survival, growth and net production of the seagrass Zostera noltei. In the absence of Ulva sp., increasing ammonium concentrations had a negative influence on the performance of Z. noltei. The presence of Ulva sp. without ammonium supply had a similar, but slightly smaller, negative effect on seagrass fitness due to light attenuation. When ammonium enrichment was combined with presence of Ulva sp., Ulva sp. ameliorated some of negative effects caused by high ammonium availability although Ulva sp. lowered the availability of light. Benthic microalgae, which increased in biomass during the experiment, seemed to play a similar role as Ulva sp.--they contributed to remove ammonium from the water, and thus, aided to keep the ammonium concentrations experienced by Z. noltei at relatively non-toxic levels. Our findings show that moderate amounts of drift macroalgae, eventually combined with increasing stocks of benthic microalgae, may aid seagrasses to alleviate toxic effects of ammonium under eutrophic conditions, which highlights the importance of high functional diversity for ecosystem resistance to anthropogenic disturbance.

  12. 1997 Toxic Hazards Research Annual Report

    Science.gov (United States)

    1998-05-01

    evaluate the potential for CF 3I to produce reproductive toxicity and to provide additional information on the effect of CF 3I exposure on the...questions raised on the effects of CF 3I exposure following the recently completed acute and subchronic inhalation toxicity studies (Dodd et al., 1997a...individuals from potential toxic consequences resulting from exposure to combustion products of advanced composite materials (ACM), this laboratory has

  13. Trichothecenes: structure-toxic activity relationships.

    Science.gov (United States)

    Wu, Qinghua; Dohnal, Vlastimil; Kuca, Kamil; Yuan, Zonghui

    2013-07-01

    Trichothecenes comprise a large family of structurally related toxins mainly produced by fungi belonging to the genus Fusarium. Among trichothecenes, type A and type B are of the most concern due to their broad and highly toxic nature. In order to address structure-activity relationships (SAR) of trichothecenes, relationships between structural features and biological effects of trichothecene mycotoxins in mammalian systems are summarized in this paper. The double bond between C-9-C-10 and the 12,13-epoxide ring are essential structural features for trichothecene toxicity. Removal of these groups results in a complete loss of toxicity. A hydroxyl group at C-3 enhances trichothecene toxicity, while this activity decreases gradually when C-3 is substituted with either hydrogen or an acetoxy group. The presence of a hydroxyl group at C-4 promotes slightly lower toxicity than an acetoxy group at the same position. The toxicity for type B trichothecenes decreases if the substituent at C-4 is changed from acetoxy to hydroxyl or hydrogen at C-4 position. The presence of hydroxyl and hydrogen groups on C-15 decreases the trichothecene toxicity in comparison with an acetoxy group attached to this carbon. Trichothecenes toxicity increases when a macrocyclic ring exists between the C-4 and C-15. At C-8 position, an oxygenated substitution at C-8 is essential for trichothecene toxicity, indicating a decrease in the toxicity if substituent change from isovaleryloxy through hydrogen to the hydroxyl group. The presence of a second epoxy ring at C-7-C-8 reduces the toxicity, whereas epoxidation at C-9-C-10 of some macrocyclic trichothecenes increases the activity. Conjugated trichothecenes could release their toxic precursors after hydrolysis in animals, and present an additional potential risk. The SAR study of trichothecenes should provide some crucial information for a better understanding of trichothecene chemical and biological properties in food contamination.

  14. Toxicity identification evaluation methods for identification of toxicants in refinery effluents

    International Nuclear Information System (INIS)

    Barten, K.A.; Mount, D.R.; Hackett, J.R.

    1993-01-01

    During the last five years, the authors have used Toxicity Identification Evaluation (TIE) methods to characterize and identify the source(s) of toxicity in effluents from dozens of municipal and industrial facilities. In most cases, specific chemicals responsible for toxicity have been identified. Although generally successful, the initial experience was that for several refinery effluents, they were able only to qualitatively characterize the presence of organic toxicants; standard toxicant identification procedures were not able to isolate specific organic chemicals. They believe that organic toxicity in these refinery effluents is caused by multiple organic compounds rather than by just a few; evidence for this includes an inability to isolate toxicity in a small number of fractions using liquid chromatography and the presence of very large numbers of compounds in isolated fractions. There is also evidence that the toxicant(s) may be ionic, in that the toxicity of whole effluent and isolated fractions often show increasing toxicity with decreasing pH. Finally, positive-pressure filtration has also reduced toxicity in some samples. In this presentation the authors summarize their experiences with refinery effluents, focusing on typical patterns they have observed and alternative procedures they have used to better understand the nature of these toxicants

  15. Studies on the toxicity of RSU-1069

    International Nuclear Information System (INIS)

    Whitmore, G.F.; Gulyas, S.

    1986-01-01

    RSU-1069 combines an aziridine function with a 2-nitroimidazole and has been reported to exhibit extraordinary radiosensitization both in vitro and in vivo. Such sensitization appears to be at variance with the electron affinity of the compound. In addition, recent experiments suggest that the compound is highly toxic to hypoxic tumor cells in vivo. On the assumption that the observed radiosensitizing ability may be a manifestation of toxicity and because of the high in vivo toxicity, we have investigated aerobic and hypoxic toxicity, both in wild type CHO cells and in mutants sensitive to a variety of DNA damaging agents. With wild type cells under aerobic conditions, the compound is approximately 50 times as toxic as misonidazole and under hypoxic conditions, approximately 250 times as toxic. The ratio of hypoxic to aerobic toxicity is approximately 80 times. Under aerobic conditions, repair-deficient mutants are 10 times as sensitive to RSU-1069 as wild type cells and approximately 100 times as sensitive under hypoxic conditions. The ratio of hypoxic to aerobic toxicity for the mutant cells is approximately 900. Based on these observations, we suggest that under aerobic conditions the aziridine function is primarily responsible for toxicity, whereas, under hypoxic conditions, the aziridine moiety combined with a reduced 2-nitroimidazole moiety produces a bifunctional agent

  16. Petroleum hydrocarbon toxicity to corals: A review.

    Science.gov (United States)

    Turner, Nicholas R; Renegar, D Abigail

    2017-06-30

    The proximity of coral reefs to coastal urban areas and shipping lanes predisposes corals to petroleum pollution from multiple sources. Previous research has evaluated petroleum toxicity to coral using a variety of methodology, including monitoring effects of acute and chronic spills, in situ exposures, and ex situ exposures with both adult and larval stage corals. Variability in toxicant, bioassay conditions, species and other methodological disparities between studies prevents comprehensive conclusions regarding the toxicity of hydrocarbons to corals. Following standardized protocols and quantifying the concentration and composition of toxicant will aid in comparison of results between studies and extrapolation to actual spills. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Rose oil (from Rosa × damascena Mill.) vapor attenuates depression-induced oxidative toxicity in rat brain.

    Science.gov (United States)

    Nazıroğlu, Mustafa; Kozlu, Süleyman; Yorgancıgil, Emre; Uğuz, Abdülhadi Cihangir; Karakuş, Kadir

    2013-01-01

    Oxidative stress is a critical route of damage in various physiological stress-induced disorders, including depression. Rose oil may be a useful treatment for depression because it contains flavonoids which include free radical antioxidant compounds such as rutin and quercetin. We investigated the effects of absolute rose oil (from Rosa × damascena Mill.) and experimental depression on lipid peroxidation and antioxidant levels in the cerebral cortex of rats. Thirty-two male rats were randomly divided into four groups. The first group was used as control, while depression was induced in the second group using chronic mild stress (CMS). Oral (1.5 ml/kg) and vapor (0.15 ml/kg) rose oil were given for 28 days to CMS depression-induced rats, constituting the third and fourth groups, respectively. The sucrose preference test was used weekly to identify depression-like phenotypes during the experiment. At the end of the experiment, cerebral cortex samples were taken from all groups. The lipid peroxidation levels in the cerebral cortex in the CMS group were higher than in control whereas their levels were decreased by rose oil vapor exposure. The vitamin A, vitamin E, vitamin C and β-carotene concentrations in the cerebral cortex were lower in the CMS group than in the control group whereas their concentrations were higher in the rose oil vapor plus CMS group. The CMS-induced antioxidant vitamin changes were not modulated by oral treatment. Glutathione peroxidase activity and reduced glutathione did not change statistically in the four groups following CMS or either treatment. In conclusion, experimental depression is associated with elevated oxidative stress while treatment with rose oil vapor induced protective effects on oxidative stress in depression.

  18. In vivo pretreatment of Eudrilus eugeniae powder attenuates β-adrenoceptor toxicity mediated by isoproterenol in rat model

    OpenAIRE

    Jaganathan Anitha; Kadarkarai Murugan; Akon Higuchi; Abdullah A. Alarfaj; Murugan A. Munusamy; Giovanni Benelli

    2016-01-01

    The present study was designed to discover the potential cardioprotective function of earthworm powder (EWP) extracted from Eudrilus eugeniae on isoproterenol (ISO)-induced myocardial infarction in male Wistar rats. The rats were divided into four groups, with six rats in each group. Certain rats were pretreated with EWP (200 mg/kg bwt) (Group III), and a myocardial infarction was then induced by subcutaneous injection of ISO (85 mg/kg bwt) (Group II). Oral pretreatment of 200 mg/kg bwt of EW...

  19. Monitoring the effectiveness of remediation techniques using sediment toxicity tests with the amphipod Eohaustorius estuarius

    International Nuclear Information System (INIS)

    Doe, K.G.; Jackman, P.M.; Lee, K.

    2002-01-01

    The results of a controlled oil release experiment of weathered crude oil was presented. The released oil was applied to a tidal saltwater marsh at Conrod's Beach, Nova Scotia, Canada. The study included 3 replicate blocks which included 2 unoiled treatments and 4 oiled treatments for each block. One unoiled site had no treatment, the second unoiled site had nutrient addition to examine the effect of nutrients. The oiled treatments included natural attenuation, nutrient addition, nutrient addition with plants, and nutrient addition with a garden aerator to introduce oxygen. A standard lab procedure was used to analyze the sediments to determine the effectiveness of the technique as well as the toxic effects on the survival of the amphipod Eohaustorius estuarius. Test results indicated that the unoiled sites were non-toxic, with a slight decrease in survival in the treatment with nutrient addition. All the oiled sites were very toxic at first, but toxicity decreased gradually with time. Treatment with nutrient addition with a garden aerator proved to be the most complete and fastest detoxification method. 8 refs., 4 tabs., 2 figs

  20. Animal data on plutonium toxicity

    International Nuclear Information System (INIS)

    Thompson, R.C.

    1975-01-01

    Animal data are necessary in the assessment of plutonium toxicity since it is unlikely that the necessary information on effects from humans will be obtained. Experiments on animals must be designed to provide understanding of the mechanisms at work if the results are to be applied to man since it is a statistical impossibility to design experiments to measure directly the low levels of risk that are of concern. Cancer induction appears to be the risk of greatest concern with the lung and bone apparently the most susceptible organs, depending upon the method of administration. Current limitations on these organs do not appear to have the safety margin formerly believed and there are some uncertainties in the extrapolation from animal data to man. (author)

  1. Toxic hazards of underground excavation

    International Nuclear Information System (INIS)

    Smith, R.; Chitnis, V.; Damasian, M.

    1982-09-01

    Inadvertent intrusion into natural or man-made toxic or hazardous material deposits as a consequence of activities such as mining, excavation or tunnelling has resulted in numerous deaths and injuries in this country. This study is a preliminary investigation to identify and document instances of such fatal or injurious intrusion. An objective is to provide useful insights and information related to potential hazards due to future intrusion into underground radioactive-waste-disposal facilities. The methodology used in this study includes literature review and correspondence with appropriate government agencies and organizations. Key categories of intrusion hazards are asphyxiation, methane, hydrogen sulfide, silica and asbestos, naturally occurring radionuclides, and various mine or waste dump related hazards

  2. Physiology and toxicity of fluoride

    Directory of Open Access Journals (Sweden)

    Dhar Vineet

    2009-01-01

    Full Text Available Fluoride has been described as an essential element needed for normal development and growth of animals and extremely useful for human beings. Fluoride is abundant in the environment and the main source of fluoride to humans is drinking water. It has been proved to be beneficial in recommended doses, and at the same time its toxicity at higher levels has also been well established. Fluoride gets accumulated in hard tissues of the body and has been know to play an important role in mineralization of bone and teeth. At high levels it has been known to cause dental and skeletal fluorosis. There are suggested effects of very high levels of fluoride on various body organs and genetic material. The purpose of this paper is to review the various aspects of fluoride and its importance in human life.

  3. Physiology and toxicity of fluoride.

    Science.gov (United States)

    Dhar, Vineet; Bhatnagar, Maheep

    2009-01-01

    Fluoride has been described as an essential element needed for normal development and growth of animals and extremely useful for human beings. Fluoride is abundant in the environment and the main source of fluoride to humans is drinking water. It has been proved to be beneficial in recommended doses, and at the same time its toxicity at higher levels has also been well established. Fluoride gets accumulated in hard tissues of the body and has been know to play an important role in mineralization of bone and teeth. At high levels it has been known to cause dental and skeletal fluorosis. There are suggested effects of very high levels of fluoride on various body organs and genetic material. The purpose of this paper is to review the various aspects of fluoride and its importance in human life.

  4. Toxic agents causing cerebellar ataxias.

    Science.gov (United States)

    Manto, Mario

    2012-01-01

    The cerebellum is particularly vulnerable to intoxication and poisoning, especially so the cerebellar cortex and Purkinje neurons. In humans, the most common cause of a toxic lesion to the cerebellar circuitry is alcohol related, but the cerebellum is also a main target of drug exposure (such as anticonvulsants, antineoplastics, lithium salts, calcineurin inhibitors), drug abuse and addiction (such as cocaine, heroin, phencyclidine), and environmental toxins (such as mercury, lead, manganese, toluene/benzene derivatives). Although data for the prevalence and incidence of cerebellar lesions related to intoxication and poisoning are still unknown in many cases, clinicians should keep in mind the list of agents that may cause cerebellar deficits, since toxin-induced cerebellar ataxias are not rare in daily practice. Moreover, the patient's status may require immediate therapies when the intoxication is life-threatening. 2012 Elsevier B.V. All rights reserved.

  5. Toxic hazards of underground excavation

    Energy Technology Data Exchange (ETDEWEB)

    Smith, R.; Chitnis, V.; Damasian, M.; Lemm, M.; Popplesdorf, N.; Ryan, T.; Saban, C.; Cohen, J.; Smith, C.; Ciminesi, F.

    1982-09-01

    Inadvertent intrusion into natural or man-made toxic or hazardous material deposits as a consequence of activities such as mining, excavation or tunnelling has resulted in numerous deaths and injuries in this country. This study is a preliminary investigation to identify and document instances of such fatal or injurious intrusion. An objective is to provide useful insights and information related to potential hazards due to future intrusion into underground radioactive-waste-disposal facilities. The methodology used in this study includes literature review and correspondence with appropriate government agencies and organizations. Key categories of intrusion hazards are asphyxiation, methane, hydrogen sulfide, silica and asbestos, naturally occurring radionuclides, and various mine or waste dump related hazards.

  6. Patient position alters attenuation effects in multipinhole cardiac SPECT

    International Nuclear Information System (INIS)

    Timmins, Rachel; Ruddy, Terrence D.; Wells, R. Glenn

    2015-01-01

    Purpose: Dedicated cardiac cameras offer improved sensitivity over conventional SPECT cameras. Sensitivity gains are obtained by large numbers of detectors and novel collimator arrangements such as an array of multiple pinholes that focus on the heart. Pinholes lead to variable amounts of attenuation as a source is moved within the camera field of view. This study evaluated the effects of this variable attenuation on myocardial SPECT images. Methods: Computer simulations were performed for a set of nine point sources distributed in the left ventricular wall (LV). Sources were placed at the location of the heart in both an anthropomorphic and a water-cylinder computer phantom. Sources were translated in x, y, and z by up to 5 cm from the center. Projections were simulated with and without attenuation and the changes in attenuation were compared. A LV with an inferior wall defect was also simulated in both phantoms over the same range of positions. Real camera data were acquired on a Discovery NM530c camera (GE Healthcare, Haifa, Israel) for five min in list-mode using an anthropomorphic phantom (DataSpectrum, Durham, NC) with 100 MBq of Tc-99m in the LV. Images were taken over the same range of positions as the simulations and were compared based on the summed perfusion score (SPS), defect width, and apparent defect uptake for each position. Results: Point sources in the water phantom showed absolute changes in attenuation of ≤8% over the range of positions and relative changes of ≤5% compared to the apex. In the anthropomorphic computer simulations, absolute change increased to 20%. The changes in relative attenuation caused a change in SPS of <1.5 for the water phantom but up to 4.2 in the anthropomorphic phantom. Changes were larger for axial than for transverse translations. These results were supported by SPS changes of up to six seen in the physical anthropomorphic phantom for axial translations. Defect width was also seen to significantly increase. The

  7. A remediation strategy based on active phytoremediation followed by natural attenuation in a soil contaminated by pyrite waste

    International Nuclear Information System (INIS)

    Clemente, Rafael; Almela, Concepcion; Bernal, M. Pilar

    2006-01-01

    Phytoremediation of metal-polluted soils can be promoted by the proper use of soil amendments and agricultural practices. A 4-year phytoremediation programme was applied to a site affected by the toxic spill of pyrite residue at Aznalcollar (Spain) in 1998, contaminated with heavy metals (Zn, Cu, Pb, Cd) and arsenic. This consisted of active phytoremediation, using organic amendments (cow manure and compost) and lime and growing two successive crops of Brassica juncea (L.) Czern., followed by natural attenuation without further intervention. Changes in soil pH, extractable metal and As concentrations, organic carbon content and microbial biomass was evaluated. The initial oxidation of metal sulphides from pyrite residues released soluble metals and reduced soil pH to extremely acidic values (mean 4.1, range 2.0-7.0). The addition of lime (up to 64 t ha -1 ) increased soil pH to adequate values for plant growth, resulting in a significant decrease in DTPA-extractable metal concentrations in all plots. Natural attenuation phase showed also a decrease in extractable metals. Organic treatments increased the soil total organic carbon, which led to higher values of microbial biomass (11.6, 15.2 and 14.9 g kg -1 TOC and 123, 170 and 275 μg g -1 biomass-C in control, compost and manure plots, respectively). Active phytoremediation followed by natural attenuation, was effective for remediation of this pyrite-polluted soil. - The addition of lime and organic amendments decreased heavy metal solubility and promoted Natural attenuation of a recently-contaminated soil

  8. A remediation strategy based on active phytoremediation followed by natural attenuation in a soil contaminated by pyrite waste

    Energy Technology Data Exchange (ETDEWEB)

    Clemente, Rafael [Department of Soil and Water Conservation and Organic Waste Management, Centro de Edafologia y Biologia Aplicada del Segura, CSIC, Campus Universitario de Espinardo, Apartado 164, 30100 Espinardo, Murcia (Spain)]. E-mail: rclemente@cebas.csic.es; Almela, Concepcion [Instituto de Agroquimica y Tecnologia de Alimentos, CSIC, Apartado 73, 46100 Burjassot, Valencia (Spain); Bernal, M. Pilar [Department of Soil and Water Conservation and Organic Waste Management, Centro de Edafologia y Biologia Aplicada del Segura, CSIC, Campus Universitario de Espinardo, Apartado 164, 30100 Espinardo, Murcia (Spain)

    2006-10-15

    Phytoremediation of metal-polluted soils can be promoted by the proper use of soil amendments and agricultural practices. A 4-year phytoremediation programme was applied to a site affected by the toxic spill of pyrite residue at Aznalcollar (Spain) in 1998, contaminated with heavy metals (Zn, Cu, Pb, Cd) and arsenic. This consisted of active phytoremediation, using organic amendments (cow manure and compost) and lime and growing two successive crops of Brassica juncea (L.) Czern., followed by natural attenuation without further intervention. Changes in soil pH, extractable metal and As concentrations, organic carbon content and microbial biomass was evaluated. The initial oxidation of metal sulphides from pyrite residues released soluble metals and reduced soil pH to extremely acidic values (mean 4.1, range 2.0-7.0). The addition of lime (up to 64 t ha{sup -1}) increased soil pH to adequate values for plant growth, resulting in a significant decrease in DTPA-extractable metal concentrations in all plots. Natural attenuation phase showed also a decrease in extractable metals. Organic treatments increased the soil total organic carbon, which led to higher values of microbial biomass (11.6, 15.2 and 14.9 g kg{sup -1} TOC and 123, 170 and 275 {mu}g g{sup -1} biomass-C in control, compost and manure plots, respectively). Active phytoremediation followed by natural attenuation, was effective for remediation of this pyrite-polluted soil. - The addition of lime and organic amendments decreased heavy metal solubility and promoted Natural attenuation of a recently-contaminated soil.

  9. Endogenous thiols enhance thallium toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Montes, Sergio; Rios, Camilo [Instituto Nacional de Neurologia y Neurocirugia, ' ' Manuel Velasco Suarez' ' , Departamento de Neuroquimica, Mexico, D.F (Mexico); Soriano, Luz; Monroy-Noyola, Antonio [Universidad Autonoma del Estado de Morelos, Laboratorio de Neuroproteccion, Facultad de Farmacia, Cuernavaca, Morelos (Mexico)

    2007-10-15

    Either L-methionine (L-met) or L-cysteine (L-cys), given alone and in combination with Prussian blue (PB) was characterized as treatment against acute thallium (Tl) toxicity in rats. Animals were intoxicated with 32 mg/kg Tl acetate corresponding to rat LD{sub 50}. Antidotal treatments were administered during 4 days, as follows: (1) vehicle, (2) L-met 100 mg/kg i.p. twice a day, (3) L-cys 100 mg/kg i.p. twice a day, (4) PB 50 mg/kg oral, twice a day, (5) L-met + PB and (6) L-cys + PB. Mortality was as follows: control 50%; L-met 80%; L-cys 80%; PB 20%; L-met + PB 90% and L-cys + PB 100%. In a different experiment, using 16 mg/kg of Tl, tissue levels of this metal were analyzed. PB treatment statistically diminished Tl content in body organs and brain regions (P < 0.01). Whereas, separate treatments of L-met and L-cys failed to decrease Tl content in organs and brain regions; while its administration in combination with PB (L-met + PB and L-cys + PB groups) lowered Tl levels in body organs in the same extent as PB group. Results indicate that L-met and L-cys administered alone or in combination with PB should not be considered suitable treatments against acute Tl toxic effects because this strategy failed to prevent mortality and Tl accumulation in brain. (orig.)

  10. Amiodarone pulmonary toxicity: Case report

    Directory of Open Access Journals (Sweden)

    Vasić Nada

    2014-01-01

    Full Text Available Introduction. Amiodarone, an antiarrhythmic drug, which contains iodine compound, has a tendency to accumulate in some organs including the lungs. This is age, drug dosage and therapy duration dependent. Case Outline. We present a case of a 73-year-old man, a smoker, who was admitted as emergency case due to severe dyspnea, tachypnea with signs of cyanosis and respiratory insufficiency. Chest x-ray revealed bilateral diffuse pulmonary shadows in the middle and upper parts of the lungs, similar to those in tuberculosis. His illness history showed chronic obstructive pulmonary disease, arterial hypertension, and atrial fibrillation which has been treated with amiodarone for six years. Sputum smears were negative for mycobacteria, and by the diagnostic elimination method for specific, non-specific and malignant disease the diagnosis of amiodarone pulmonary toxicity was made. Fiberoptic bronchoscopy and pathohistological findings of bronchiolitis obliterans organizing pneumonia confirmed the diagnosis. As the first therapeutic approach, amiodarone therapy was stopped. Then, systemic therapy with methylprednisolone 21 (sodium succinate 40 mg i.v. daily during the first two weeks was initiated and continued with daily dose of methylprednisolone 30 mg orally during the next three months. The patient showed a marked subjective improvement during the first week, which was followed by the improvement of respiratory function and withdrawal of pulmonary changes with complete radiographic and CT resolution after eight months. Conclusion. Amiodarone pulmonary toxicity should be taken into consideration, especially in elderly patients with respiratory symptoms and pulmonary changes, even if only a low dose of amiodarone is administred over a longer time period.

  11. Electrocardiographic Manifestations of Benzodiazepine Toxicity

    Directory of Open Access Journals (Sweden)

    Nahid Kazemzadeh

    2014-11-01

    Full Text Available Background: The aim of this study was to evaluate and compare the clinical and electrocardiographic (ECG manifestations of benzodiazepines (BZs. Methods: In this retrospective study, all BZ-poisoned patients hospitalized at Loghman Hakim Hospital between September 2010 and March 2011 were evaluated. Patients’ information including age, sex, time elapsed between the ingestion and presentation, and type of the BZ used were extracted from the patients' charts and recorded. ECGs on presentation to the emergency department (ED were evaluated and parameters such as PR interval, QRS duration, corrected QT, amplitude of S wave in lead I, height of R wave and R/S ratio in the lead aVR were also measured and recorded. Results: Oxazepam, chlordiazepoxide, lorazepam, alprazolam, diazepam, and clonazepam were ingested by 9 (3%, 13 (4.4%, 29 (9.9%, 105 (35.8%, 65 (22.2%, and 72 (24.6% patients, respectively. Mean PR interval was reported to be 0.16 ± 0.03 sec and PR interval of greater than 200 msec was detected in 12 (4.5% patients. Mean QRS duration was 0.07 ± 0.01sec and QRS≥120 msec was observed in 7 (2.6% cases. Conclusion: Diazepam is the only BZ that does not cause QRS widening and oxazepam is the only one not causing PR prolongation. It can be concluded that if a patient refers with a decreased level of consciousness and accompanying signs of BZ toxicity, QRS widening in ECG rules out diazepam, whereas PR prolongation rules out oxazepam toxicity.

  12. Reproductive toxicity testing of vaccines

    International Nuclear Information System (INIS)

    Verdier, Francois; Barrow, Paul C.; Burge, Joeelle

    2003-01-01

    Vaccines play a major role in the prevention of human birth defects by protecting the pregnant woman from teratogenic or otherwise harmful infections. Until now, it has not been common practice to perform preclinical developmental toxicity tests for new vaccines. Despite the excellent safety record of vaccines, increased attention is now being given to the feasibility of screening new vaccines for developmental hazards in animals before their use in humans. Contrary to previous assumptions, many vaccines are now given to potentially pregnant women. Any new components of the vaccine formulation (adjuvants, excipients, stabilisers, preservatives, etc...) could also be tested for influences on development, although based on past experience the risks are limited by the very low dosages used. The conferred immunity following vaccination lasts for several years. Therefore, the developing conceptus may theoretically be exposed to the induced antibodies and/or sensitised T-cells, even if the pregnant woman was last vaccinated during childhood (particularly if she encounters the antigen during pregnancy through exposure to infection). However, it should be kept in mind that viral or bacterial infections represent a higher risk for a pregnant woman than the potential adverse effects related to vaccination or the associated immune response. Non-clinical safety studies may be employed as an aid for hazard identification. In these studies interactions of the vaccine with the maternal immune system or with the developmental systems of the offspring are considered. Post-natal examinations are necessary to detect all possible manifestations of developmental toxicity, such as effects on the immune system. Species selection for the preclinical studies is based on immunogenicity to the vaccine and the relative timing and rate of transfer of maternal antibodies to the offspring. A single study design is proposed for the pre- and post-natal developmental assessments of vaccines in

  13. Brunenders: a partially attenuated historic poliovirus type I vaccine strain.

    Science.gov (United States)

    Sanders, Barbara P; Liu, Ying; Brandjes, Alies; van Hoek, Vladimir; de Los Rios Oakes, Isabel; Lewis, John; Wimmer, Eckard; Custers, Jerome H H V; Schuitemaker, Hanneke; Cello, Jeronimo; Edo-Matas, Diana

    2015-09-01

    Brunenders, a type I poliovirus (PV) strain, was developed in 1952 by J. F. Enders and colleagues through serial in vitro passaging of the parental Brunhilde strain, and was reported to display partial neuroattenuation in monkeys. This phenotype of attenuation encouraged two vaccine manufacturers to adopt Brunenders as the type I component for their inactivated poliovirus vaccines (IPVs) in the 1950s, although today no licensed IPV vaccine contains Brunenders. Here we confirmed, in a transgenic mouse model, the report of Enders on the reduced neurovirulence of Brunenders. Although dramatically neuroattenuated relative to WT PV strains, Brunenders remains more virulent than the attenuated oral vaccine strain, Sabin 1. Importantly, the neuroattenuation of Brunenders does not affect in vitro growth kinetics and in vitro antigenicity, which were similar to those of Mahoney, the conventional type I IPV vaccine strain. We showed, by full nucleotide sequencing, that Brunhilde and Brunenders differ at 31 nucleotides, eight of which lead to amino acid changes, all located in the capsid. Upon exchanging the Brunenders capsid sequence with that of the Mahoney capsid, WT neurovirulence was regained in vivo, suggesting a role for the capsid mutations in Brunenders attenuation. To date, as polio eradication draws closer, the switch to using attenuated strains for IPV is actively being pursued. Brunenders preceded this novel strategy as a partially attenuated IPV strain, accompanied by decades of successful use in the field. Providing data on the attenuation of Brunenders may be of value in the further construction of attenuated PV strains to support the grand pursuit of the global eradication of poliomyelitis.

  14. TOXICITY BEHAVIORS IN ORGANIZATIONS: STUDY OF RELIABILITY AND VALIDITY OF TOXIC EMOTIONAL EXPERIENCES SCALE

    OpenAIRE

    Bektas, Meral; Erkal, Pinar

    2016-01-01

    In toxic organizations which are mostly destructive instead of being constrictive towards its employees, toxicity behaviors emerge as a result of the formal and informal relationships. Toxicity behaviors are often negatively affect motivation, job satisfaction or performance of the employees in workplace. Basic toxicity behaviors in organizations are: extreme jealousy, biting words, emphasis  superiority emphasis, getting angry, offending employees, strict control, heavy job workload, limited...

  15. Classification of baseline toxicants for QSAR predictions to replace fish acute toxicity studies.

    Science.gov (United States)

    Nendza, Monika; Müller, Martin; Wenzel, Andrea

    2017-03-22

    Fish acute toxicity studies are required for environmental hazard and risk assessment of chemicals by national and international legislations such as REACH, the regulations of plant protection products and biocidal products, or the GHS (globally harmonised system) for classification and labelling of chemicals. Alternative methods like QSARs (quantitative structure-activity relationships) can replace many ecotoxicity tests. However, complete substitution of in vivo animal tests by in silico methods may not be realistic. For the so-called baseline toxicants, it is possible to predict the fish acute toxicity with sufficient accuracy from log K ow and, hence, valid QSARs can replace in vivo testing. In contrast, excess toxicants and chemicals not reliably classified as baseline toxicants require further in silico, in vitro or in vivo assessments. Thus, the critical task is to discriminate between baseline and excess toxicants. For fish acute toxicity, we derived a scheme based on structural alerts and physicochemical property thresholds to classify chemicals as either baseline toxicants (=predictable by QSARs) or as potential excess toxicants (=not predictable by baseline QSARs). The step-wise approach identifies baseline toxicants (true negatives) in a precautionary way to avoid false negative predictions. Therefore, a certain fraction of false positives can be tolerated, i.e. baseline toxicants without specific effects that may be tested instead of predicted. Application of the classification scheme to a new heterogeneous dataset for diverse fish species results in 40% baseline toxicants, 24% excess toxicants and 36% compounds not classified. Thus, we can conclude that replacing about half of the fish acute toxicity tests by QSAR predictions is realistic to be achieved in the short-term. The long-term goals are classification criteria also for further groups of toxicants and to replace as many in vivo fish acute toxicity tests as possible with valid QSAR

  16. AMAP, the alleged non-toxic isomer of acetaminophen, is toxic in rat and human liver

    NARCIS (Netherlands)

    Hadi, M; Dragovic, S.; van Swelm, R; Herpers, B; van de Water, B.; Russel, RG; Commandeur, J.N.M.; Groothuis, G.M.

    2013-01-01

    N-acetyl-meta-aminophenol (AMAP) is generally considered as a non-toxic regioisomer of the wellknown hepatotoxicant acetaminophen (APAP). However, so far, AMAP has only been shown to be non-toxic in mice and hamsters. To investigate whether AMAP could also be used as non-toxic analog of APAP in rat

  17. AMAP, the alleged non-toxic isomer of acetaminophen, is toxic in rat and human liver

    NARCIS (Netherlands)

    Hadi, Mackenzie; Dragovic, Sanja; van Swelm, Rachel; Herpers, Bram; van de Water, Bob; Russel, Frans G. M.; Commandeur, Jan N. M.; Groothuis, Geny M. M.

    N-acetyl-meta-aminophenol (AMAP) is generally considered as a non-toxic regioisomer of the well-known hepatotoxicant acetaminophen (APAP). However, so far, AMAP has only been shown to be non-toxic in mice and hamsters. To investigate whether AMAP could also be used as non-toxic analog of APAP in rat

  18. Investigation of the Relationship of Some Antihypertensive Drugs with Oxidant/Antioxidant Parameters and DNA Damage on Rat Uterus Tissue

    Directory of Open Access Journals (Sweden)

    Mustafa Talip Sener

    2011-01-01

    Full Text Available Background: In this study, we investigated the effects of treatment with chronic antihypertensivedrugs (clonidine, methyldopa, amlodipine, ramipril and rilmenidine on oxidant-antioxidantparameters and toxic effects on DNA in rat uterus tissue. In addition, uterus tissues were examinedhistopathologically.Materials and Methods: A total of 36 albino Wistar rats were divided into the following six groups:0.075 mg/kg clonidine group; 100 mg/kg methyldopa group; 2 mg/kg amlodipine group; 2.5 mg/kgramipril group; 0.5 mg/kg rilmenidine group; and the healthy group. Rats underwent chronic drugadministration for 30 days and at the end, biochemical and histopathological examinations wereperformed. All data were subjected to one-way ANOVA test.Results: We divided these drugs into the following three groups according to their effects on ratuteri: (I mild negative effects (clonidine, (II moderate negative effects (rilmenidine, methyldopaand (III drugs which had severe negative effects (amlodipine, ramipril.Conclusion: These data may help with selection of antihypertensive drugs, in order to determinewhich drugs have the lowest toxicity in pregnant and non-pregnant (pre-pregnancy women.

  19. Attenuation of trace organic compounds (TOrCs) inbioelectrochemical systems

    KAUST Repository

    Werner, Craig M.

    2015-04-01

    Microbial fuel cells (MFCs) and microbial electrolysis cells (MECs) are two types of microbial bioelectrochemical systems (BESs) that use microorganisms to convert chemical energy in wastewaters into useful energy products such as (bio)electricity (MFC) or hydrogen gas (MEC). These two systems were evaluated for their capacity to attenuate trace organic compounds (TOrCs), commonly found in municipal wastewater, under closed circuit (current generation) and open circuit (no current generation) conditions, using acetate as the carbon source. A biocide was used to evaluate attenuation in terms of biotransformation versus sorption. The difference in attenuation observed before and after addition of the biocide represented biotransformation, while attenuation after addition of a biocide primarily indicated sorption. Attenuation of TOrCs was similar in MFCs and MECs for eight different TOrCs, except for caffeine and trimethoprim where slightly higher attenuation was observed in MECs. Electric current generation did not enhance attenuation of the TOrCs except for caffeine, which showed slightly higher attenuation under closed circuit conditions in both MFCs and MECs. Substantial sorption of the TOrCs occurred to the biofilm-covered electrodes, but no consistent trend could be identified regarding the physico-chemical properties of the TOrCs tested and the extent of sorption. The octanol-water distribution coefficient at pH 7.4 (log DpH 7.4) appeared to be a reasonable predictor for sorption of some of the compounds (carbamazepine, atrazine, tris(2-chloroethyl) phosphate and diphenhydramine) but not for others (N,N-Diethyl-meta-toluamide). Atenolol also showed high levels of sorption despite being the most hydrophilic in the suite of compounds studied (log DpH 7.4=-1.99). Though BESs do not show any inherent advantages over conventional wastewater treatment, with respect to TOrC removal, overall removals in BESs are similar to that reported for conventional wastewater

  20. Estimation of Toxicity Equivalent Concentration (TEQ) of ...

    African Journals Online (AJOL)

    Estimation of Toxicity Equivalent Concentration (TEQ) of carcinogenic polycyclic aromatic hydrocarbons in soils from Idu Ekpeye playground and University of Port ... Effective soil remediation and detoxification method like Dispersion by chemical reaction technology should be deployed to clean-up sites to avoid soil toxicity ...

  1. Phytochemical screening, proximate analysis and acute toxicity ...

    African Journals Online (AJOL)

    Phytochemical screening results indicate the presence of saponins, flavonoids, phytosterols and phenols. Acute toxicity study showed there was no mortality at 8000 mg/kg of the extract. The results indicate that the plant is rich in phytochemicals and is relatively safe. Key words: Phytochemicals, acute toxicity, proximate ...

  2. National Toxic Substance Incidents Program (NTSIP)

    Centers for Disease Control (CDC) Podcasts

    2011-02-03

    This podcast gives an overview of the three components of the National Toxic Substance Incidents Program: state surveillance, national database, and response teams.  Created: 2/3/2011 by Agency for Toxic Substances and Disease Registry.   Date Released: 2/3/2011.

  3. Chapter 6: Selenium Toxicity to Aquatic Organisms

    Science.gov (United States)

    This chapter addresses the characteristics and nature of organic selenium (Se) toxicity to aquatic organisms, based on the most current state of scientific knowledge. As such, the information contained in this chapter relates to the 'toxicity assessment' phase of aquatic ecologi...

  4. Determination of toxic elements in Malaysian foodstuffs

    International Nuclear Information System (INIS)

    Hamzah, Z.; Wood, A.K.H.; Mahmood, C.S.; Hamzah, S.

    1988-01-01

    This project is concentrating on the analysis of toxic elements content in seafoods including fishes, mussel, squid and prawn. Samples were collected from various places throughout Malay Peninsular. Samples were prepared according to RCA research protocol - nuclear techniques for toxic element in foodstuffs. Techniques used for elemental analysis were neutron activation analysis (instrumental and radiochemical) and anodic stripping voltametry. (author). 9 refs, 9 tabs

  5. Toxicity of Pesticides. Agrichemical Fact Sheet 2.

    Science.gov (United States)

    Hock, Winand K.

    This fact sheet gives the acute oral and dermal toxicity (LD 50) of over 250 pesticides in lab animals. The chemicals are categorized as fungicides, herbicides, insecticides, or miscellaneous compounds. One or more trade names are given for each pesticide. In addition, a brief explanation of toxicity determination is given. (BB)

  6. ACUTE TOXICITY STUDIES AND ANTIDOTAL THERAPY OF ...

    African Journals Online (AJOL)

    ACUTE TOXICITY STUDIES AND ANTIDOTAL THERAPY OF ETHANOL EXTRACT OF JATROPHA CURCAS SEEDS IN EXPERIMENTAL ANIMALS. ... with the aim of investigating the toxicity of the ethanol seed extract of JC in rats, mice, and chicks; and also to use conventional antidotes to treat intoxication in rats due to ...

  7. The toxicity of particles from combustion processes

    International Nuclear Information System (INIS)

    Henderson, R.F.; Mauderly, J.L.

    1991-01-01

    The pulmonary toxicity of inhaled particles will depend on their size, solubility and inherent toxicity. Many combustion-derived particles, such as soot and fly ash, are of a respirable size and, being poorly soluble, are retained for prolonged periods in the lung. The acute toxicity of fly ash from coal combustion was compared to that of a known toxic particle, alpha-quartz, by exposures of rats to 35 mg/m 3 of each type of particle for 7 hr/day, 5 days/wk for 4 wk. The acute pulmonary toxicity was measured by analysis of bronchoalveolar lavage fluid. One year after the exposures, fibrosis with granulomas was observed in the quartz-exposed rats, while little or no fibrosis developed in the fly-ash-exposed rats. The toxicity of soot from diesel exhaust was determined by chronic (30 mo) exposures of rats, 7 hr/day, 5 days/wk to exhaust containing 0.35, 3.5 or 7.0 mg/m 3 soot. The two higher exposures caused persistent pulmonary inflammation, fibrosis and neoplasmas. Rats exposed to the lowest concentration demonstrated no toxic responses and there was no life shortening caused by any exposure. Ongoing comparative studies indicate that pure carbon black particles cause responses similar to those caused by diesel exhaust, indicating that much of the toxicity induced by the diesel soot results from the presence of the large lung burdens of carbonaceous particles

  8. Predictive Model of Systemic Toxicity (SOT)

    Science.gov (United States)

    In an effort to ensure chemical safety in light of regulatory advances away from reliance on animal testing, USEPA and L’Oréal have collaborated to develop a quantitative systemic toxicity prediction model. Prediction of human systemic toxicity has proved difficult and remains a ...

  9. Toxicity identification evaluation of cosmetics industry wastewater.

    Science.gov (United States)

    de Melo, Elisa Dias; Mounteer, Ann H; Leão, Lucas Henrique de Souza; Bahia, Renata Cibele Barros; Campos, Izabella Maria Ferreira

    2013-01-15

    The cosmetics industry has shown steady growth in many developing countries over the past several years, yet little research exists on toxicity of wastewaters it generates. This study describes a toxicity identification evaluation conducted on wastewater from a small Brazilian hair care products manufacturing plant. Physicochemical and ecotoxicological analyses of three wastewater treatment plant inlet and outlet samples collected over a six month period revealed inefficient operation of the treatment system and thus treated wastewater organic matter, suspended solids and surfactants contents consistently exceeded discharge limits. Treated wastewater also presented high acute toxicity to Daphnia similis and chronic toxicity to Ceriodaphnia dubia and Pseudokirchneriella subcapitata. This toxicity was associated with suspended solids, volatile or sublatable and non-polar to moderately polar organic compounds that could be recovered in filtration and aeration residues. Seven surfactants used in the largest quantities in the production process were highly toxic to P. subcapitata and D. similis. These results indicated that surfactants, important production raw materials, are a probable source of toxicity, although other possible sources, such as fragrances, should not be discarded. Improved treatment plant operational control may reduce toxicity and lower impact of wastewater discharge to receiving waters. Copyright © 2012 Elsevier B.V. All rights reserved.

  10. ALKALOIDAL COMPOSITION AND TOXICITY STUDIES OF THREE ...

    African Journals Online (AJOL)

    Mattock's test for unsaturated pyrrolizidine alkaloids (hepatotoxic) revealed that only C. retusa contained these alkaloids amongst the three species. This indicated that this is a potentially toxic specie. The alkaloids of C. retusa were toxic to albino (Wistar) rats. Marked microscopic lesions were found, principally in the liver.

  11. Quantitative SPECT brain imaging: Effects of attenuation and detector response

    International Nuclear Information System (INIS)

    Gilland, D.R.; Jaszczak, R.J.; Bowsher, J.E.; Turkington, T.G.; Liang, Z.; Greer, K.L.; Coleman, R.E.

    1993-01-01

    Two physical factors that substantially degrade quantitative accuracy in SPECT imaging of the brain are attenuation and detector response. In addition to the physical factors, random noise in the reconstructed image can greatly affect the quantitative measurement. The purpose of this work was to implement two reconstruction methods that compensate for attenuation and detector response, a 3D maximum likelihood-EM method (ML) and a filtered backprojection method (FB) with Metz filter and Chang attenuation compensation, and compare the methods in terms of quantitative accuracy and image noise. The methods were tested on simulated data of the 3D Hoffman brain phantom. The simulation incorporated attenuation and distance-dependent detector response. Bias and standard deviation of reconstructed voxel intensities were measured in the gray and white matter regions. The results with ML showed that in both the gray and white matter regions as the number of iterations increased, bias decreased and standard deviation increased. Similar results were observed with FB as the Metz filter power increased. In both regions, ML had smaller standard deviation than FB for a given bias. Reconstruction times for the ML method have been greatly reduced through efficient coding, limited source support, and by computing attenuation factors only along rays perpendicular to the detector

  12. Segmented attenuation correction using artificial neural networks in positron tomography

    International Nuclear Information System (INIS)

    Yu, S.K.; Nahmias, C.

    1996-01-01

    The measured attenuation correction technique is widely used in cardiac positron tomographic studies. However, the success of this technique is limited because of insufficient counting statistics achievable in practical transmission scan times, and of the scattered radiation in transmission measurement which leads to an underestimation of the attenuation coefficients. In this work, a segmented attenuation correction technique has been developed that uses artificial neural networks. The technique has been validated in phantoms and verified in human studies. The results indicate that attenuation coefficients measured in the segmented transmission image are accurate and reproducible. Activity concentrations measured in the reconstructed emission image can also be recovered accurately using this new technique. The accuracy of the technique is subject independent and insensitive to scatter contamination in the transmission data. This technique has the potential of reducing the transmission scan time, and satisfactory results are obtained if the transmission data contain about 400 000 true counts per plane. It can predict accurately the value of any attenuation coefficient in the range from air to water in a transmission image with or without scatter correction. (author)

  13. Radiation induced time dependent attenuation in a fiber

    International Nuclear Information System (INIS)

    Kelly, R.E.; Lyons, P.B.; Looney, L.D.

    1985-01-01

    Characteristics describing the time dependent attenuation coefficient of an optical fiber during and following a very short and intense radiation pulse are analyzed. This problem is important for transmission applications when the fiber is subjected to gamma, electron, or neutron beams. Besides time, the attenuation coefficient is a function of temperature, dose rate, dose, nature of the radiation (n, e, γ), fiber composition and purity, pre-existing solid state defects, and wavelength of the transmitted signal. The peak attenuation for a given fiber is mainly determined by the dose rate and pulse length, but temperature and strain (or athermal) annealing also contribute to a partial recovery during the pulse duration. The peak attenuation per unit dose appears to be smaller at high doses, perhaps caused by particle track overlap, which produces a saturation effect. After pulse termination, the attenuation coefficient tends to recover towards its pre-radiation value at different rates, depending upon the factors mentioned above. In particular, ionized electrons relax back to the positive lattice ions at a rate which depends upon initial separation distance and temperature. The initial separation distance is a function of beam energy. Some electrons will encounter a trap in the lattice and may recombine by quantum mechanical tunneling or be removed by photons (hence, absorption). Besides ionization, radiation may induce lattice displacements which in turn produce additional absorption centers. The displacement contribution has a different time constant than that associated with ionization. These topics, as they influence fiber characteristics, are discussed, along with supporting experimental data

  14. Pentoxifylline Attenuates Cardiac Remodeling Induced by Tobacco Smoke Exposure

    Energy Technology Data Exchange (ETDEWEB)

    Minicucci, Marcos; Oliveira, Fernando; Santos, Priscila; Polegato, Bertha; Roscani, Meliza; Fernandes, Ana Angelica; Lustosa, Beatriz; Paiva, Sergio; Zornoff, Leonardo; Azevedo, Paula, E-mail: paulasa@fmb.unesp.br [Faculdade de Medicina de Botucatu, Universidade Estadual Paulista, São Paulo, SP (Brazil)

    2016-05-15

    Tobacco smoke exposure is an important risk factor for cardiac remodeling. Under this condition, inflammation, oxidative stress, energy metabolism abnormalities, apoptosis, and hypertrophy are present. Pentoxifylline has anti‑inflammatory, anti-apoptotic, anti-thrombotic and anti-proliferative properties. The present study tested the hypothesis that pentoxifylline would attenuate cardiac remodeling induced by smoking. Wistar rats were distributed in four groups: Control (C), Pentoxifylline (PX), Tobacco Smoke (TS), and PX-TS. After two months, echocardiography, invasive blood pressure measurement, biochemical, and histological studies were performed. The groups were compared by two-way ANOVA with a significance level of 5%. TS increased left atrium diameter and area, which was attenuated by PX. In the isolated heart study, TS lowered the positive derivate (+dp/dt), and this was attenuated by PX. The antioxidants enzyme superoxide dismutase and glutathione peroxidase were decreased in the TS group; PX recovered these activities. TS increased lactate dehydrogenase (LDH) and decreased 3-hydroxyacyl Coenzyme A dehydrogenases (OH-DHA) and citrate synthase (CS). PX attenuated LDH, 3-OH-DHA and CS alterations in TS-PX group. TS increased IL-10, ICAM-1, and caspase-3. PX did not influence these variables. TS induced cardiac remodeling, associated with increased inflammation, oxidative stress, apoptosis, and changed energy metabolism. PX attenuated cardiac remodeling by reducing oxidative stress and improving cardiac bioenergetics, but did not act upon cardiac cytokines and apoptosis.

  15. A practical attenuation compensation method for cone beam spect

    International Nuclear Information System (INIS)

    Manglos, S.H.; Jaszczak, R.J.; Floyd, C.E.; Greer, K.L.; Coleman, R.E.

    1987-01-01

    An algorithm for attenuation compensation of cone beam SPECT images has been developed and implemented. The algorithm is based on a multiplicative post-processing method previously used for parallel and fan beam geometries. This method computes the compensation from the estimated average attenuation of photons originating from each image pixel. In the present development, a uniform attenuation coefficient inside of the body contour is assumed, although the method could be extended to include a non-uniform attenuation map. The algorithm is tested with experimental projections of a phantom obtained using a cone beam collimator. Profiles through the reconstructed images are presented as a quantitative test of the improvement due to the compensation. The algorithm provides adequate compensation for attenuation in a simple uniform cylindrical phantom, and the computational time is short compared to that expected for iterative reconstruction techniques. Also observed are image distortions in some reconstructed slices when the source distribution extends beyond the edge of the cone beam axial field-of-view

  16. Wild type measles virus attenuation independent of type I IFN

    Directory of Open Access Journals (Sweden)

    Horvat Branka

    2008-02-01

    Full Text Available Abstract Background Measles virus attenuation has been historically performed by adaptation to cell culture. The current dogma is that attenuated virus strains induce more type I IFN and are more resistant to IFN-induced protection than wild type (wt. Results The adaptation of a measles virus isolate (G954-PBL by 13 passages in Vero cells induced a strong attenuation of this strain in vivo. The adapted virus (G954-V13 differs from its parental strain by only 5 amino acids (4 in P/V/C and 1 in the M gene. While a vaccine strain, Edmonston Zagreb, could replicate equally well in various primate cells, both G954 strains exhibited restriction to the specific cell type used initially for their propagation. Surprisingly, we observed that both G954 strains induced type I IFN, the wt strain inducing even more than the attenuated ones, particularly in human plasmacytoid Dendritic Cells. Type I IFN-induced protection from the infection of both G954 strains depended on the cell type analyzed, being less efficient in the cells used to grow the viral strain. Conclusion Thus, mutations in M and P/V/C proteins can critically affect MV pathogenicity, cellular tropism and lead to virus attenuation without interfering with the α/β IFN system.

  17. Principles underlying rational design of live attenuated influenza vaccines

    Science.gov (United States)

    Jang, Yo Han

    2012-01-01

    Despite recent innovative advances in molecular virology and the developments of vaccines, influenza virus remains a serious burden for human health. Vaccination has been considered a primary countermeasure for prevention of influenza infection. Live attenuated influenza vaccines (LAIVs) are particularly attracting attention as an effective strategy due to several advantages over inactivated vaccines. Cold-adaptation, as a classical means for attenuating viral virulence, has been successfully used for generating safe and effective donor strains of LAIVs against seasonal epidemics and occasional pandemics. Recently, the advent of reverse genetics technique expedited a variety of rational strategies to broaden the pool of LAIVs. Considering the breadth of antigenic diversity of influenza virus, the pool of LAIVs is likely to equip us with better options for controlling influenza pandemics. With a brief reflection on classical attenuating strategies used at the initial stage of development of LAIVs, especially on the principles underlying the development of cold-adapted LAIVs, we further discuss and outline other attenuation strategies especially with respect to the rationales for attenuation, and their practicality for mass production. Finally, we propose important considerations for a rational vaccine design, which will provide us with practical guidelines for improving the safety and effectiveness of LAIVs. PMID:23596576

  18. Radiation treatment of toxic chemicals

    International Nuclear Information System (INIS)

    Lee, M.J.; Jung, I.H.; Jo, S.K.

    2010-01-01

    Polychlorinated biphenyls (PCBs) were commercially produced from 1920s as complex mixtures containing multiple isomers for a variety of applications. They are very toxic, chemically stable and resist microbial, photochemical, chemical, and thermal degradation. The public, legal, and scientific concerns about PCBs arose from research indicating they were environmental contaminants that had a potential to adversely impact the environment, and, therefore, were undesirable as commercial products. Eventually, most producers reduced or stopped production of PCBs in the 1970s. Stockholm convention on POPs (Persistent Organic Pollutants), which was effective on May 2004 and 151 nations including Korea were joined on June 2005, asked to dispose of PCBs by 2028 with environmental friendly methods. Korean government also has declared to conduct by 2015. According to the Environmental law of Korea, over 2 ppm of PCBs has to be decomposed by legal methods of incineration and thermal destruction. But those are inapplicable owing to the environmental groups. KAERI(Korea Atomic Energy Research Institute) has recently developed a remarkable technology for radiation treatment of toxic chemicals including chlorides using an electron beam accelerator. Electron beam accelerator of 2.5 MeV energy and 100 kW power capacity was used to decompose of PCBs having been used as a commercial transformer oil for more than 30 years. The oil were irradiated with ∼ 0.1 percent of TEA (Triethyl Amin) to make chloride ion aparted off from the PCBs into precipitate at the conditions of normal temperature and pressure. The concentrations of PCBs were measured by GC (Gas Chromatography) with ECD (Electron Capture Detector) following the KS (Korean Standard) test procedure. Electron beam should be a useful tool for environmental conservation. Residual concentrations of PCBs after irradiation were depended on the absorption dose of electron beam energy. Advantages comparing to other methods such as

  19. Role of oxidative stress in methamphetamine-induced dopaminergic toxicity mediated by protein kinase Cδ.

    Science.gov (United States)

    Shin, Eun-Joo; Duong, Chu Xuan; Nguyen, Xuan-Khanh Thi; Li, Zhengyi; Bing, Guoying; Bach, Jae-Hyung; Park, Dae Hun; Nakayama, Keiichi; Ali, Syed F; Kanthasamy, Anumantha G; Cadet, Jean Lud; Nabeshima, Toshitaka; Kim, Hyoung-Chun

    2012-06-15

    This study examined the role of protein kinase C (PKC) isozymes in methamphetamine (MA)-induced dopaminergic toxicity. Multiple-dose administration of MA did not significantly alter PKCα, PKCβI, PKCβII, or PKCζ expression in the striatum, but did significantly increase PKCδ expression. Gö6976 (a co-inhibitor of PKCα and -β), hispidin (PKCβ inhibitor), and PKCζ pseudosubstrate inhibitor (PKCζ inhibitor) did not significantly alter MA-induced behavioral impairments. However, rottlerin (PKCδ inhibitor) significantly attenuated behavioral impairments in a dose-dependent manner. In addition, MA-induced behavioral impairments were not apparent in PKCδ knockout (-/-) mice. MA-induced oxidative stress (i.e., lipid peroxidation and protein oxidation) was significantly attenuated in rottlerin-treated mice and was not apparent in PKCδ (-/-) mice. Consistent with this, MA-induced apoptosis (i.e., terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling-positive apoptotic cells) was significantly attenuated in rottlerin-treated mice. Furthermore, MA-induced increases in the dopamine (DA) turnover rate and decreases in tyrosine hydroxylase (TH) activity and the expression of TH, dopamine transporter (DAT), and vesicular monoamine transporter 2 (VMAT2) were not significantly observed in rottlerin-treated or PKCδ (-/-) mice. Our results suggest that PKCδ gene expression is a key mediator of oxidative stress and dopaminergic damage induced by MA. Thus, inhibition of PKCδ may be a useful target for protection against MA-induced neurotoxicity. Copyright © 2012 Elsevier B.V. All rights reserved.

  20. Update on ocular toxicity of ethambutol

    Directory of Open Access Journals (Sweden)

    Priscilla Makunyane

    2016-08-01

    Full Text Available The purpose of this review is to update clinicians on available literature on the ocular toxicity of ethambutol and the type of eye care to be provided to patients treated with these medications. Ethambutol is a commonly used first-line anti-tuberculosis drug. Since its first use in the 1960s, ocular toxicity is described as related to dose and duration, and it is reversible on therapy discontinuation. However, the reversibility of the toxic optic neuropathy remains controversial. The mechanism of ocular toxicity owing to ethambutol is still under investigation. Other than discontinuing the drug, no specific treatment is available for the optic neuropathy caused by ethambutol. Doctors prescribing ethambutol should be aware of the ocular toxicity, and the drug should be used with proper patient education and ophthalmic monitoring.

  1. Harmonizing human exposure and toxicity characterization

    DEFF Research Database (Denmark)

    Fantke, Peter; Jolliet, O.; McKone, T.E.

    2017-01-01

    The UNEP-SETAC Life Cycle Initiative has launched a project to provide global guidance and build consensus on environmental life cycle impact assessment (LCIA) indicators. Human health effects from exposure to toxic chemicals was selected as impact category due to high relevance of human toxicity...... and harmonizing human toxicity characterization in LCIA. Building on initial work for the far-field and indoor air environments, and combining it with latest work on near-field consumer and occupational exposure assessment, dose-response and severity data, we aim at providing revised guidance on the development...... and use of impact factors for toxic chemicals. We propose to couple fate processes in consumer and occupational environments with existing environmental compartments and processes via a consistent and mass balance-based set of transfer fractions to quantify overall aggregated exposure to toxic substances...

  2. Toxicities of selected substances to freshwater biota

    Energy Technology Data Exchange (ETDEWEB)

    Hohreiter, D.W.

    1980-05-01

    The amount of data available concerning the toxicity of various substances to freshwater biota is so large that it is difficult to use in a practical situation, such as environmental impact assessment. In this document, summary tables are presented showing acute and/or chronic toxicity of selected substances for various groups of aquatic biota. Each entry is referenced to its original source so that details concerning experimental conditions may be consulted. In addition, general information concerning factors modifying toxicity, synergisms, evidence of bioaccumulation, and water quality standards and criteria for the selected substances is given. The final table is a general toxicity table designed to provide an easily accessible and general indication of toxicity of selected substances in aquatic systems.

  3. In vivo evidence of methamphetamine induced attenuation of brain tissue oxygenation as measured by EPR oximetry

    Science.gov (United States)

    Weaver, John; Yang, Yirong; Purvis, Rebecca; Weatherwax, Theodore; Rosen, Gerald M.; Liu, Ke Jian

    2014-01-01

    Abuse of methamphetamine (METH) is a major and significant societal problem in the US, as a number of studies have suggested that METH is associated with increased cerebrovascular events, hemorrhage or vasospasm. Although cellular and molecular mechanisms involved in METH-induced toxicity are not completely understood, changes in brain O2 may play an important role and contribute to METH-induced neurotoxicity including dopaminergic receptor degradation. Given that O2 is the terminal electron acceptor for many enzymes that are important in brain function, the impact of METH on brain tissue pO2 in vivo remains largely uncharacterized. This study investigated striatal tissue pO2 changes in male C57BL/6 mice (16–20g) following METH administration using EPR oximetry, a highly sensitive modality to measure pO2 in vivo, in situ and in real time. We demonstrate that 20 min after a single injection of METH (8 mg/kg i.v.), the striatal pO2 was reduced to 81% of the pretreatment level and exposure to METH for 3 consecutive days further attenuated striatal pO2 to 64%. More importantly, pO2 did not recover fully to control levels even 24 hrs after administration of a single dose of METH. and continual exposure to METH exacerbates the condition. We also show a reduction in cerebral blood flow associated with a decreased brain pO2 indicating an ischemic condition. Our findings suggests that administration of METH can attenuate brain tissue pO2, which may lead to hypoxic insult, thus a risk factor for METH-induced brain injury and the development of stroke in young adults. PMID:24412707

  4. Resveratrol attenuates methylglyoxal-induced mitochondrial dysfunction and apoptosis by Sestrin2 induction

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Kyuhwa; Seo, Suho; Han, Jae Yun; Ki, Sung Hwan; Shin, Sang Mi, E-mail: smshin@chosun.ac.kr

    2014-10-15

    Methylglyoxal is found in high levels in the blood and other tissues of diabetic patients and exerts deleterious effects on cells and tissues. Previously, we reported that resveratrol, a polyphenol in grapes, induced the expression of Sestrin2 (SESN2), a novel antioxidant protein, and inhibited hepatic lipogenesis. This study investigated whether resveratrol protects cells from the methylglyoxal-induced toxicity via SESN2 induction. Methylglyoxal significantly induced cell death in HepG2 cells. However, cells pretreated with resveratrol were rescued from methylglyoxal-induced apoptosis. Resveratrol attenuated glutathione (GSH) depletion and ROS production promoted by methylglyoxal. Moreover, mitochondrial damage was observed by methylglyoxal treatment, but resveratrol restored mitochondrial function, as evidenced by the observed lack of mitochondrial permeability transition and increased ADP/ATP ratio. Resveratrol treatment inhibited SESN2 depletion elicited by methylglyoxal. SESN2 overexpression repressed methylglyoxal-induced mitochondrial dysfunction and apoptosis. Likewise, rotenone-induced cytotoxicity was not observed in SESN2 overexpressed cells. Furthermore, siRNA knockdown of SESN2 reduced the ability of resveratrol to prevent methylglyoxal-induced mitochondrial permeability transition. In addition, when mice were exposed to methylglyoxal after infection of Ad-SESN2, the plasma levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and GSH depletion by methylglyoxal in liver was reduced in Ad-SESN2 infected mice. Our results demonstrated that resveratrol is capable of protecting cells from methylglyoxal-induced mitochondrial dysfunction and oxidative stress via SESN2 induction. - Highlights: • Resveratrol decreased methylglyoxal-induced apoptosis. • Resveratrol attenuated GSH depletion and ROS production promoted by methylglyoxal. • Resveratrol restored the mitochondrial function by Sestrin2 induction. • Induction of Sestrin2

  5. Resveratrol attenuates methylglyoxal-induced mitochondrial dysfunction and apoptosis by Sestrin2 induction

    International Nuclear Information System (INIS)

    Seo, Kyuhwa; Seo, Suho; Han, Jae Yun; Ki, Sung Hwan; Shin, Sang Mi

    2014-01-01

    Methylglyoxal is found in high levels in the blood and other tissues of diabetic patients and exerts deleterious effects on cells and tissues. Previously, we reported that resveratrol, a polyphenol in grapes, induced the expression of Sestrin2 (SESN2), a novel antioxidant protein, and inhibited hepatic lipogenesis. This study investigated whether resveratrol protects cells from the methylglyoxal-induced toxicity via SESN2 induction. Methylglyoxal significantly induced cell death in HepG2 cells. However, cells pretreated with resveratrol were rescued from methylglyoxal-induced apoptosis. Resveratrol attenuated glutathione (GSH) depletion and ROS production promoted by methylglyoxal. Moreover, mitochondrial damage was observed by methylglyoxal treatment, but resveratrol restored mitochondrial function, as evidenced by the observed lack of mitochondrial permeability transition and increased ADP/ATP ratio. Resveratrol treatment inhibited SESN2 depletion elicited by methylglyoxal. SESN2 overexpression repressed methylglyoxal-induced mitochondrial dysfunction and apoptosis. Likewise, rotenone-induced cytotoxicity was not observed in SESN2 overexpressed cells. Furthermore, siRNA knockdown of SESN2 reduced the ability of resveratrol to prevent methylglyoxal-induced mitochondrial permeability transition. In addition, when mice were exposed to methylglyoxal after infection of Ad-SESN2, the plasma levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and GSH depletion by methylglyoxal in liver was reduced in Ad-SESN2 infected mice. Our results demonstrated that resveratrol is capable of protecting cells from methylglyoxal-induced mitochondrial dysfunction and oxidative stress via SESN2 induction. - Highlights: • Resveratrol decreased methylglyoxal-induced apoptosis. • Resveratrol attenuated GSH depletion and ROS production promoted by methylglyoxal. • Resveratrol restored the mitochondrial function by Sestrin2 induction. • Induction of Sestrin2

  6. Natural attenuation process via microbial oxidation of arsenic in a high Andean watershed.

    Science.gov (United States)

    Leiva, Eduardo D; Rámila, Consuelo d P; Vargas, Ignacio T; Escauriaza, Cristian R; Bonilla, Carlos A; Pizarro, Gonzalo E; Regan, John M; Pasten, Pablo A

    2014-01-01

    Rivers in northern Chile have arsenic (As) concentrations at levels that are toxic for humans and other organisms. Microorganism-mediated redox reactions have a crucial role in the As cycle; the microbial oxidation of As (As(III) to As(V)) is a critical transformation because it favors the immobilization of As in the solid phase. We studied the role of microbial As oxidation for controlling the mobility of As in the extreme environment found in the Chilean Altiplano (i.e., > 4000 meters above sea level (masl) and Azufre River sub-basin, where the natural attenuation of As from hydrothermal discharge (pH 4-6) was observed. As(III) was actively oxidized by a microbial consortium, leading to a significant decrease in the dissolved As concentrations and a corresponding increase in the sediment's As concentration downstream of the hydrothermal source. In-situ oxidation experiments demonstrated that the As oxidation required biological activity, and microbiological molecular analysis confirmed the presence of As(III)-oxidizing groups (aroA-like genes) in the system. In addition, the pH measurements and solid phase analysis strongly suggested that the As removal mechanism involved adsorption or coprecipitation with Fe-oxyhydroxides. Taken together, these results indicate that the microorganism-mediated As oxidation contributed to the attenuation of As concentrations and the stabilization of As in the solid phase, therefore controlling the amount of As transported downstream. This study is the first to demonstrate the microbial oxidation of As in Altiplano basins and its relevance in the immobilization of As. © 2013.

  7. Methamphetamine-induced neurotoxicity is attenuated in transgenic mice with a null mutation for interleukin-6.

    Science.gov (United States)

    Ladenheim, B; Krasnova, I N; Deng, X; Oyler, J M; Polettini, A; Moran, T H; Huestis, M A; Cadet, J L

    2000-12-01

    Increasing evidence implicates apoptosis as a major mechanism of cell death in methamphetamine (METH) neurotoxicity. The involvement of a neuroimmune component in apoptotic cell death after injury or chemical damage suggests that cytokines may play a role in METH effects. In the present study, we examined if the absence of IL-6 in knockout (IL-6-/-) mice could provide protection against METH-induced neurotoxicity. Administration of METH resulted in a significant reduction of [(125)I]RTI-121-labeled dopamine transporters in the caudate-putamen (CPu) and cortex as well as depletion of dopamine in the CPu and frontal cortex of wild-type mice. However, these METH-induced effects were significantly attenuated in IL-6-/- animals. METH also caused a decrease in serotonin levels in the CPu and hippocampus of wild-type mice, but no reduction was observed in IL-6-/- animals. Moreover, METH induced decreases in [(125)I]RTI-55-labeled serotonin transporters in the hippocampal CA3 region and in the substantia nigra-reticulata but increases in serotonin transporters in the CPu and cingulate cortex in wild-type animals, all of which were attenuated in IL-6-/- mice. Additionally, METH caused increased gliosis in the CPu and cortices of wild-type mice as measured by [(3)H]PK-11195 binding; this gliotic response was almost completely inhibited in IL-6-/- animals. There was also significant protection against METH-induced DNA fragmentation, measured by the number of terminal deoxynucleotidyl transferase-mediated dUTP nick-end-labeled (TUNEL) cells in the cortices. The protective effects against METH toxicity observed in the IL-6-/- mice were not caused by differences in temperature elevation or in METH accumulation in wild-type and mutant animals. Therefore, these observations support the proposition that IL-6 may play an important role in the neurotoxicity of METH.

  8. Development of a human live attenuated West Nile infectious DNA vaccine: Suitability of attenuating mutations found in SA14-14-2 for WN vaccine design

    Energy Technology Data Exchange (ETDEWEB)

    Yamshchikov, Vladimir, E-mail: yaximik@gmail.com; Manuvakhova, Marina; Rodriguez, Efrain

    2016-01-15

    Direct attenuation of West Nile (WN) virus strain NY99 for the purpose of vaccine development is not feasible due to its high virulence and pathogenicity. Instead, we created highly attenuated chimeric virus W1806 with the serological identity of NY99. To further attenuate W1806, we investigated effects of mutations found in Japanese encephalitis virus vaccine SA14-14-2. WN viruses carrying all attenuating mutations lost infectivity in mammalian, but not in mosquito cells. No single reversion restored infectivity in mammalian cells, although increased infectivity in mosquito cells was observed. To identify a subset of mutations suitable for further attenuation of W1806, we analyzed effects of E{sub 138}K and K{sub 279}M changes on virulence, growth properties, and immunogenicity of derivatized W956, from which chimeric W1806 inherited its biological properties and attenuation profile. Despite strong dominant attenuating effect, introduction of only two mutations was not sufficient for attenuating W1806 to the safety level acceptable for human use. - Highlights: • Further attenuation of a WN vaccine precursor is outlined. • Effect of SA14-14-2 attenuating mutations is tested. • Mechanism of attenuation is proposed and illustrated. • The need for additional attenuating mutations is justified.

  9. Toxic chemical risk acceptance criteria

    International Nuclear Information System (INIS)

    Craig, D.K.; Davis, J.; Lee, L.; Lein, P.; Omberg, S.

    1992-01-01

    This paper presents recommendations of a subcommittee of the Westinghouse M ampersand 0 Nuclear Facility Safety Committee concerning toxic chemical risk acceptance criteria. Two sets of criteria have been developed, one for use in the hazard classification of facilities, and the second for use in comparing risks in DOE non-reactor nuclear facility Safety Analysis Reports. The Emergency Response Planning Guideline (ERPG) values are intended to provide estimates of concentration ranges for specific chemicals above which exposure would be expected to lead to adverse heath effects of increasing severity for ERPG-1, -2, and -3s. The subcommittee recommends that criteria for hazard class or risk range be based on ERPGs for all chemicals. Probability-based Incremental Cancer Risk (ICR) criteria are recommended for additional analyses of risks from all known or suspected human carcinogens. Criteria are given for both on-site and off-site exposure. The subcommittee also recommends that the 5-minute peak concentration be compared with the relevant criterion with no adjustment for exposure time. Since ERPGs are available for only a limited number of chemicals, the subcommittee has developed a proposed hierarchy of concentration limit parameters for the different criteria

  10. Molecular mechanisms of fluoride toxicity.

    Science.gov (United States)

    Barbier, Olivier; Arreola-Mendoza, Laura; Del Razo, Luz María

    2010-11-05

    Halfway through the twentieth century, fluoride piqued the interest of toxicologists due to its deleterious effects at high concentrations in human populations suffering from fluorosis and in in vivo experimental models. Until the 1990s, the toxicity of fluoride was largely ignored due to its "good reputation" for preventing caries via topical application and in dental toothpastes. However, in the last decade, interest in its undesirable effects has resurfaced due to the awareness that this element interacts with cellular systems even at low doses. In recent years, several investigations demonstrated that fluoride can induce oxidative stress and modulate intracellular redox homeostasis, lipid peroxidation and protein carbonyl content, as well as alter gene expression and cause apoptosis. Genes modulated by fluoride include those related to the stress response, metabolic enzymes, the cell cycle, cell-cell communications and signal transduction. The primary purpose of this review is to examine recent findings from our group and others that focus on the molecular mechanisms of the action of inorganic fluoride in several cellular processes with respect to potential physiological and toxicological implications. This review presents an overview of the current research on the molecular aspects of fluoride exposure with emphasis on biological targets and their possible mechanisms of involvement in fluoride cytotoxicity. The goal of this review is to enhance understanding of the mechanisms by which fluoride affects cells, with an emphasis on tissue-specific events in humans. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  11. Investigation of olive mill wastewater (OMW) ozonation efficiency with the use of a battery of selected ecotoxicity and human toxicity assays

    Energy Technology Data Exchange (ETDEWEB)

    Siorou, Sofia [Section of Animal Biology, Department of Biology, Faculty of Sciences, University of Patras, GR-26500 Patras (Greece); Vgenis, Theodoros T.; Dareioti, Margarita A. [Laboratory of Biochemical Engineering and Environmental Technology, Department of Chemical Engineering, University of Patras, 1 Karatheodori Str., University Campus, GR-26500 Patras (Greece); Vidali, Maria-Sophia; Efthimiou, Ioanna [Department of Environmental and Natural Resources Management, University of Patras, 2 Seferi Str., GR-30100 Agrinio (Greece); Kornaros, Michael [Laboratory of Biochemical Engineering and Environmental Technology, Department of Chemical Engineering, University of Patras, 1 Karatheodori Str., University Campus, GR-26500 Patras (Greece); Vlastos, Dimitris [Department of Environmental and Natural Resources Management, University of Patras, 2 Seferi Str., GR-30100 Agrinio (Greece); Dailianis, Stefanos, E-mail: sdailianis@upatras.gr [Section of Animal Biology, Department of Biology, Faculty of Sciences, University of Patras, GR-26500 Patras (Greece)

    2015-07-15

    Highlights: • Raw- and ozonated-olive mill wastewater (OMW) toxic effects were investigated. • A battery of biological assays and toxic endpoints were used. • Ozonation for up to 300 min attenuates OMW toxicity, following phenols’ reduction. • Further OMW ozonation (>300 min) could enhance OMW toxicity. • OMW ozonation efficacy depends on OMW-derived intermediates and high NO{sub 3}{sup −}–N levels. - Abstract: The effects of olive mill wastewater (OMW) on a battery of biological assays, before and during the ozonation process, were investigated in order to assess ozone’s efficiency in removing phenolic compounds from OMW and decreasing the concomitant OMW toxicity. Specifically, ozonated-OMW held for 0, 60, 120, 300, 420, 540 min in a glass bubble reactor, showed a drastic reduction of OMW total phenols (almost 50%) after 300 min of ozonation with a concomitant decrease of OMW toxicity. In particular, the acute toxicity test primarily performed in the fairy shrimp Thamnocephalus platyurus (Thamnotoxkit F™ screening toxicity test) showed a significant attenuation of OMW-induced toxic effects, after ozonation for a period of 120 and in a lesser extent 300 min, while further treatment resulted in a significant enhancement of ozonated-OMW toxic effects. Furthermore, ozonated-OMW-treated mussel hemocytes showed a significant attenuation of the ability of OMW to cause cytotoxic (obtained by the use of NRRT assay) effects already after an ozonation period of 120 and to a lesser extent 300 min. In accordance with the latter, OMW-mediated oxidative (enhanced levels of superoxide anions and lipid peroxidation by-products) and genotoxic (induction of DNA damage) effects were diminished after OMW ozonation for the aforementioned periods of time. The latter was also revealed by the use of cytokinesis block micronucleus (CBMN) assay in human lymphocytes exposed to different concentrations of both raw- and ozonated-OMW for 60, 120 and 300 min. Those findings

  12. Necroptosis Mediates TNF-Induced Toxicity of Hippocampal Neurons

    Directory of Open Access Journals (Sweden)

    Shan Liu

    2014-01-01

    Full Text Available Tumor necrosis factor-α (TNF-α is a critical proinflammatory cytokine regulating neuroinflammation. Elevated levels of TNF-α have been associated with various neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease. However, the signaling events that lead to TNF-α-initiated neurotoxicity are still unclear. Here, we report that RIP3-mediated necroptosis, a form of regulated necrosis, is activated in the mouse hippocampus after intracerebroventricular injection of TNF-α. RIP3 deficiency attenuates TNF-α-initiated loss of hippocampal neurons. Furthermore, we characterized the molecular mechanism of TNF-α-induced neurotoxicity in HT-22 hippocampal neuronal cells. HT-22 cells are sensitive to TNF-α only upon caspase blockage and subsequently undergo necrosis. The cell death is suppressed by knockdown of CYLD or RIP1 or RIP3 or MLKL, suggesting that this necrosis is necroptosis and mediated by CYLD-RIP1-RIP3-MLKL signaling pathway. TNF-α-induced necroptosis of HT-22 cells is largely independent of both ROS accumulation and calcium influx although these events have been shown to be critical for necroptosis in certain cell lines. Taken together, these data not only provide the first in vivo evidence for a role of RIP3 in TNF-α-induced toxicity of hippocampal neurons, but also demonstrate that TNF-α promotes CYLD-RIP1-RIP3-MLKL-mediated necroptosis of hippocampal neurons largely bypassing ROS accumulation and calcium influx.

  13. Attenuation correction method for single photon emission CT

    Energy Technology Data Exchange (ETDEWEB)

    Morozumi, Tatsuru; Nakajima, Masato [Keio Univ., Yokohama (Japan). Faculty of Science and Technology; Ogawa, Koichi; Yuta, Shinichi

    1983-10-01

    A correction method (Modified Correction Matrix method) is proposed to implement iterative correction by exactly measuring attenuation constant distribution in a test body, calculating a correction factor for every picture element, then multiply the image by these factors. Computer simulation for the comparison of the results showed that the proposed method was specifically more effective to an application to the test body, in which the rate of attenuation constant change is large, than the conventional correction matrix method. Since the actual measurement data always contain quantum noise, the noise was taken into account in the simulation. However, the correction effect was large even under the noise. For verifying its clinical effectiveness, the experiment using an acrylic phantom was also carried out. As the result, the recovery of image quality in the parts with small attenuation constant was remarkable as compared with the conventional method.

  14. Development of electrothermal actuation based planar variable optical attenuators (VOAs)

    International Nuclear Information System (INIS)

    Lee, Chengkuo; Yeh, J Andrew

    2006-01-01

    Several sorts of MEMS (Microelectromechanical Systems) based have been demonstrated by using electrostatic actuation scheme up to date. The comb drive and parallel plate are the two most common electrostatic actuators that have been well studied in variable optical attenuator (VOA) applications. In addition to the known retro-reflection type of optical attenuation being realized by our new devices driven by electrothermal actuators in present study, a novel planar tilted mirror with rotational and translation moving capability is proposed by using electrothermal actuators as well. Using electrothermal actuators to provide said planar tilted mirror with rotational and translational displacement has granted us a more efficient way to perform the light attenuation for in-plane structure. The static and transient characteristics of devices operated at ambient room temperature environment show good repeatability and stability

  15. Statistical modeling of optical attenuation measurements in continental fog conditions

    Science.gov (United States)

    Khan, Muhammad Saeed; Amin, Muhammad; Awan, Muhammad Saleem; Minhas, Abid Ali; Saleem, Jawad; Khan, Rahimdad

    2017-03-01

    Free-space optics is an innovative technology that uses atmosphere as a propagation medium to provide higher data rates. These links are heavily affected by atmospheric channel mainly because of fog and clouds that act to scatter and even block the modulated beam of light from reaching the receiver end, hence imposing severe attenuation. A comprehensive statistical study of the fog effects and deep physical understanding of the fog phenomena are very important for suggesting improvements (reliability and efficiency) in such communication systems. In this regard, 6-months real-time measured fog attenuation data are considered and statistically investigated. A detailed statistical analysis related to each fog event for that period is presented; the best probability density functions are selected on the basis of Akaike information criterion, while the estimates of unknown parameters are computed by maximum likelihood estimation technique. The results show that most fog attenuation events follow normal mixture distribution and some follow the Weibull distribution.

  16. Determination of Dimensionless Attenuation Coefficient in Shaped Resonators

    Science.gov (United States)

    Daniels, C.; Steinetz, B.; Finkbeiner, J.; Raman, G.; Li, X.

    2003-01-01

    The value of dimensionless attenuation coefficient is an important factor when numerically predicting high-amplitude acoustic waves in shaped resonators. Both the magnitude of the pressure waveform and the quality factor rely heavily on this dimensionless parameter. Previous authors have stated the values used, but have not completely explained their methods. This work fully describes the methodology used to determine this important parameter. Over a range of frequencies encompassing the fundamental resonance, the pressure waves were experimentally measured at each end of the shaped resonators. At the corresponding dimensionless acceleration, the numerical code modeled the acoustic waveforms generated in the resonator using various dimensionless attenuation coefficients. The dimensionless attenuation coefficient that most closely matched the pressure amplitudes and quality factors of the experimental and numerical results was determined to be the value to be used in subsequent studies.

  17. Iterative methods for photoacoustic tomography in attenuating acoustic media

    Science.gov (United States)

    Haltmeier, Markus; Kowar, Richard; Nguyen, Linh V.

    2017-11-01

    The development of efficient and accurate reconstruction methods is an important aspect of tomographic imaging. In this article, we address this issue for photoacoustic tomography. To this aim, we use models for acoustic wave propagation accounting for frequency dependent attenuation according to a wide class of attenuation laws that may include memory. We formulate the inverse problem of photoacoustic tomography in attenuating medium as an ill-posed operator equation in a Hilbert space framework that is tackled by iterative regularization methods. Our approach comes with a clear convergence analysis. For that purpose we derive explicit expressions for the adjoint problem that can efficiently be implemented. In contrast to time reversal, the employed adjoint wave equation is again damping and, thus has a stable solution. This stability property can be clearly seen in our numerical results. Moreover, the presented numerical results clearly demonstrate the efficiency and accuracy of the derived iterative reconstruction algorithms in various situations including the limited view case.

  18. Ultrasonic attenuation of CdSe at low temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, B.J., E-mail: braulio@ula.v [Centro de Estudios de Semiconductores, Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes Apartado de Correos No.1, La Hechicera, Merida 5251 (Venezuela, Bolivarian Republic of); Calderon, E.; Bracho, D.B. [Centro de Estudios de Semiconductores, Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes Apartado de Correos No.1, La Hechicera, Merida 5251 (Venezuela, Bolivarian Republic of); Perez, J.F. [Laboratorio de Instrumentacion Cientifica, Facultad de Ciencias, Universidad de Los Andes Apartado de Correos No.1, La Hechicera, Merida 5251 (Venezuela, Bolivarian Republic of)

    2010-08-01

    The ultrasonic attenuation of a single crystal of CdSe has been investigated over the temperature range from 1.2 to 300 K at frequencies of 10, 30 and 90 MHz. We report here the temperature dependence of the attenuation in the range 1.2-30 K for piezoactive and non-piezoactive acoustic waves. A temperature-induced relaxation for two piezoactive waves, which scale with frequency towards higher temperatures, was found. A modified Hutson and White model with a new parameter {gamma} is proposed to explain the relaxation maxima of our data and others in the literature. In this model the parameter {gamma}, which seems to be closely related to the compensation, takes into account the impurities-sound wave piezoelectric coupling. By inverting the proposed expression for the sound attenuation to obtain the electrical conductivity from the relaxation, it is found that impurity conductivity of the hopping type is the dominant conduction process at low temperatures.

  19. Ultrasonic attenuation of CdSe at low temperatures

    International Nuclear Information System (INIS)

    Fernandez, B.J.; Calderon, E.; Bracho, D.B.; Perez, J.F.

    2010-01-01

    The ultrasonic attenuation of a single crystal of CdSe has been investigated over the temperature range from 1.2 to 300 K at frequencies of 10, 30 and 90 MHz. We report here the temperature dependence of the attenuation in the range 1.2-30 K for piezoactive and non-piezoactive acoustic waves. A temperature-induced relaxation for two piezoactive waves, which scale with frequency towards higher temperatures, was found. A modified Hutson and White model with a new parameter γ is proposed to explain the relaxation maxima of our data and others in the literature. In this model the parameter γ, which seems to be closely related to the compensation, takes into account the impurities-sound wave piezoelectric coupling. By inverting the proposed expression for the sound attenuation to obtain the electrical conductivity from the relaxation, it is found that impurity conductivity of the hopping type is the dominant conduction process at low temperatures.

  20. Consideration of natural attenuation. In remedation contaminated sites

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-04-15

    Upon the proposal submitted by ist Standing committee 5 (Contaminated Sites Committee - ALA) the Federal / State Working Group on Soil protection employed an ad hoc subcommittee dealing with considering natural attenuation in remediating contaminated sites and preparing an inter-State position paper. In the present position paper the way how to consider natural attenuation in practical remediation of contaminated sites is described. The systematic approach outlined allows an understandable decision-finding. A way is shown how the competent soil protection authorities may exercise discretion and in the framework of checking the appropriateness of measures may decide on the implementation of MNA based on a MNA concept (MNA = monitored natural attenuation). It is, however, also explained that when carrying out MNA a decision always made in an individual case is concerned which should be made in a close agreement between the obligated party and the authority.

  1. Fast neutron attenuation measurements for detection of illicit materials

    International Nuclear Information System (INIS)

    Lee, Hee Seock; Chung, Chin Wha; Guon, Ki Il; Lee, Bo Young; Ko, Seung Kook; Shin, Yong Mu

    2002-01-01

    Experiments were carried out to develop a novel method using neutron attenuation for the detection of illicit materials. By using pulsed fast neutrons generated from a Bi target bombarded with a 2 GeV electron beam, attenuation spectra of C, N, and O have been measured to study the feasibility of a practical application. The spectral dependence on the material thickness and the geometrical distribution as well as the ability to identify different elements in a layered environment have been studied. For the elements mentioned here, the total cross sections have been obtained from the measured attenuation spectra and compared with ENDF-VI, which showed good agreement. The study confirms that a conventional low energy electron linac can be put into a practical use, and some practical idea is presented

  2. The frequency attenuation effect in identity and associative priming.

    Science.gov (United States)

    Nievas, Francisco

    2010-05-01

    Three lexical decision experiments were carried out, where the masked priming paradigm is used to study the role of the frequency attenuation effect (more priming in low-frequency target words than in high-frequency target words) in repetition and associative priming, manipulating Prime Duration (PD) and Stimulus Onset Asynchrony (SOA). A new concept was introduced, Minimum Time Threshold (MTT), this is, the minimum time interval of exposure to the masked word in order to become aware of it. Results support the notion that MTT is a key to the appearance of the frequency attenuation effect when enough word processing time is allowed. Results do not support the unified explanation of masked priming and long-term priming as proposed by Bodner and Masson (2001). Moreover, information feedback from the semantic level was not the reason for the frequency attenuation effect in repetition priming.

  3. Inorganic contaminants attenuation in acid mine drainage by fly ash and fly ash-ordinary Portland cement (OPC) blends : column experiments

    International Nuclear Information System (INIS)

    Gitari, W.M.; Petrik, L.F.; Etchebers, O.; Key, D.L.; Okujeni, C.

    2010-01-01

    The infiltration of acid mine drainage (AMD) material into mine voids is one of the environmental impacts of underground coal mining. In this study, the mitigation of AMD in a mine void was simulated in laboratory conditions. Various mixtures of fly ash, solid residues, and Portland cement were added to packed columns over a 6-month period. The fly ash additions generated near-neutral to alkaline pH levels, which in turn induced precipitation, co-precipitation, and adsorption contaminant attenuation mechanisms. A modelling study demonstrated that the precipitation of ferrihydrite, Al-hydroxides, Al-oxyhydroxysulphates, gypsum, ettringite, manganite, and rhodochrosite lowered contaminant levels. Results of the study indicated that the pH regime and acidity level of the AMD strongly influenced both the leaching of the toxic trace elements as well as the attenuation of the AMD. 3 refs., 2 figs.

  4. A toxicity reduction evaluation for an oily waste treatment plant exhibiting episodic effluent toxicity.

    Science.gov (United States)

    Erten-Unal, M; Gelderloos, A B; Hughes, J S

    1998-07-30

    A Toxicity Reduction Evaluation (TRE) was conducted on the oily wastewater treatment plant (Plant) at a Naval Fuel Depot. The Plant treats ship and ballast wastes, berm water from fuel storage areas and wastes generated in the fuel reclamation plant utilizing physical/chemical treatment processes. In the first period of the project (Period I), the TRE included chemical characterization of the plant wastewaters, monitoring the final effluent for acute toxicity and a thorough evaluation of each treatment process and Plant operating procedures. Toxicity Identification Evaluation (TIE) procedures were performed as part of the overall TRE to characterize and identify possible sources of toxicity. Several difficulties were encountered because the effluent was saline, test organisms were marine species and toxicity was sporadic and unpredictable. The treatability approach utilizing enhancements, improved housekeeping, and operational changes produced substantial reductions in the acute toxicity of the final effluent. In the second period (Period II), additional acute toxicity testing and chemical characterization were performed through the Plant to assess the long-term effects of major unit process improvements for the removal of toxicity. The TIE procedures were also modified for saline wastewaters to focus on suspected class of toxicants such as surfactants. The TRE was successful in reducing acute toxicity of the final effluent through process improvements and operational modifications. The results indicated that the cause of toxicity was most likely due to combination of pollutants (matrix effect) rather than a single pollutant.

  5. Pesticide Toxicity Index: a tool for assessing potential toxicity of pesticide mixtures to freshwater aquatic organisms

    Science.gov (United States)

    Nowell, Lisa H.; Norman, Julia E.; Moran, Patrick W.; Martin, Jeffrey D.; Stone, Wesley W.

    2014-01-01

    Pesticide mixtures are common in streams with agricultural or urban influence in the watershed. The Pesticide Toxicity Index (PTI) is a screening tool to assess potential aquatic toxicity of complex pesticide mixtures by combining measures of pesticide exposure and acute toxicity in an additive toxic-unit model. The PTI is determined separately for fish, cladocerans, and benthic invertebrates. This study expands the number of pesticides and degradates included in previous editions of the PTI from 124 to 492 pesticides and degradates, and includes two types of PTI for use in different applications, depending on study objectives. The Median-PTI was calculated from median toxicity values for individual pesticides, so is robust to outliers and is appropriate for comparing relative potential toxicity among samples, sites, or pesticides. The Sensitive-PTI uses the 5th percentile of available toxicity values, so is a more sensitive screening-level indicator of potential toxicity. PTI predictions of toxicity in environmental samples were tested using data aggregated from published field studies that measured pesticide concentrations and toxicity to Ceriodaphnia dubia in ambient stream water. C. dubia survival was reduced to ≤ 50% of controls in 44% of samples with Median-PTI values of 0.1–1, and to 0% in 96% of samples with Median-PTI values > 1. The PTI is a relative, but quantitative, indicator of potential toxicity that can be used to evaluate relationships between pesticide exposure and biological condition.

  6. Note: Attenuation motion of acoustically levitated spherical rotor

    Science.gov (United States)

    Lü, P.; Hong, Z. Y.; Yin, J. F.; Yan, N.; Zhai, W.; Wang, H. P.

    2016-11-01

    Here we observe the attenuation motion of spherical rotors levitated by near-field acoustic radiation force and analyze the factors that affect the duration time of free rotation. It is found that the rotating speed of freely rotating rotor decreases exponentially with respect to time. The time constant of exponential attenuation motion depends mainly on the levitation height, the mass of rotor, and the depth of concave ultrasound emitter. Large levitation height, large mass of rotor, and small depth of concave emitter are beneficial to increase the time constant and hence extend the duration time of free rotation.

  7. Viscosity and attenuation of sound wave in high density deuterium

    International Nuclear Information System (INIS)

    Inoue, Kazuko; Ariyasu, Tomio

    1985-01-01

    The penetration of low frequency sound wave into the fuel deuterium is discussed as for laser fusion. The sound velocity and the attenuation constant due to viscosity are calculated for high density (n = 10 24 -- 10 27 cm -3 , T = 10 -1 -- 10 4 eV) deuterium. The shear viscosity of free electron gas and the bulk viscosity due to ion-ion interaction mainly contribute to the attenuation of sound wave. The sound wave of the frequency below 10 10 Hz can easily penetrate through the compressed fuel deuterium of diameter 1 -- 10 3 μm. (author)

  8. Ultrasonic attenuation measurements and 'glassy' behaviour of neutron irradiated quartz

    International Nuclear Information System (INIS)

    Laermans, C.; Esteves, V.; Vanelstraete, A.

    1986-01-01

    The ultrasonic attenuation of longitudinal acoustic waves in slightly disordered crystalline quartz has been measured over a temperature range from 1.3 to 300 K, using the pulse-echo technique. Neutron irradiation is demonstrated to increase the ultrasonic attenuation at low temperatures indicating the presence of two-level tunneling systems similar to those of glasses. The present low-temperature acoustic results agree with a frequency independence and a T 3 behaviour for the relaxation process predicted by the two-level tunneling TLS-model where the regime ωT 1 >> 1 holds. (author)

  9. Prediction of slant path rain attenuation statistics at various locations

    Science.gov (United States)

    Goldhirsh, J.

    1977-01-01

    The paper describes a method for predicting slant path attenuation statistics at arbitrary locations for variable frequencies and path elevation angles. The method involves the use of median reflectivity factor-height profiles measured with radar as well as the use of long-term point rain rate data and assumed or measured drop size distributions. The attenuation coefficient due to cloud liquid water in the presence of rain is also considered. Absolute probability fade distributions are compared for eight cases: Maryland (15 GHz), Texas (30 GHz), Slough, England (19 and 37 GHz), Fayetteville, North Carolina (13 and 18 GHz), and Cambridge, Massachusetts (13 and 18 GHz).

  10. Measurement of linear attenuation coefficient of different materials

    International Nuclear Information System (INIS)

    Ali, M. M.

    2013-07-01

    In this research we study the linear attenuation coefficient from the materials concrete, brick, mixture concrete and iron. In the secondary standard dosimetry laboratory in Atomic Energy from different distance by use Cs-137 sours, chamber farmer 2675 A-600 cc-S/N 0511, and electrometer 2670 A-S/N 114. Found the value of linear attenuation coefficient of concert in the range 0.167 cm -1 , the brick in the range 0.063 -1 and mixture concrete and iron in the range 0.253cm -1 .(Author)

  11. Radiation-induced attenuation in integrated optical materials

    International Nuclear Information System (INIS)

    Evans, B.D.

    1989-01-01

    This paper reports that three materials commonly employed in opto-electronic integrated circuits evaluated for radiation-induced optical attenuation in the range 300 nm to 3000 nm. These include optically clear epoxy and crystalline lithium niobate after Co-60 exposure and crystalline tellurium dioxide after mixed gamma/fast-neutron exposure. In all these materials, however, induced loss was restricted to shorter wavelengths; attenuation induced at the telecommunications windows near 850, 1300 and 1550 nm was <0.1 dB/cm

  12. Continental Fog Attenuation Empirical Relationship from Measured Visibility Data

    Directory of Open Access Journals (Sweden)

    F. Nadeem

    2010-12-01

    Full Text Available Free Space Optics (FSO has the great potential for future communication applications. However, weather influenced reduced availability had been the main cause for its restricted growth. Among different weather influences fog plays the major role. A new model generalized for all FSO wavelengths, has been proposed for the prediction of continental fog attenuation using visibility data. The performance of the proposed model has been compared with well known models for measured attenuation data of Continental fog. The comparison has been performed in terms of Root Mean Square Error (RMSE.

  13. Evaluation of X ray attenuation by means of radiographic images

    International Nuclear Information System (INIS)

    Barros, Frieda Saicla; Paredes, Ramon S.C.; Godoi, Walmor C.; Souza, Gabriel Pinto de

    2011-01-01

    This paper's main goal is to adopt a qualitative methodology to evaluate the attenuation of x-radiation through X-ray images in polymeric materials plus residual lead. To determinate the images it was initially used an experimental setup at the Laboratory for Materials Diagnostics LACTEC. These results correspond to a more qualitative analysis, even with quantitative answers. Through analysis of radiographic images we can measure the intensity of radiation that goes through the plate, making possible to establish a relationship between the attenuation coefficient and the thickness of the material. (author)

  14. Attenuation of Gamma Rays by Concrete . Lead Slag Composites

    International Nuclear Information System (INIS)

    Ismail, I.M.; Sweelam, M.H.; Zaghloul, Y.R.; Aly, H.F.

    2008-01-01

    Using of wastes and industrial by-products as concrete aggregate to be used as structural and radiation shielded material has increased in the recent years. Concrete was mixed with different amounts of lead slag extracted from recycling of the spent automotive batteries as fine aggregates. The lead slag was used as partial replacement of sand in the studied composites. The concrete composites obtained were characterized in terms of density, water absorption, porosity, compressive strength and attenuation of γ- rays with different energies. The attenuation coefficient and the half value thickness of the different matrices were calculated and discussed

  15. Paraquat: model for oxidant-initiated toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Bus, J.S.; Gibson, J.E.

    1984-04-01

    Paraquat, a quaternary ammonium bipyridyl herbicide, produces degenerative lesions in the lung after systemic administration to man and animals. The pulmonary toxicity of paraquat resembles in several ways the toxicity of several other lung toxins, including oxygen, nitrofurantoin and bleomycin. Although a definitive mechanism of toxicity of parquat has not been delineated, a cyclic single electron reduction/oxidation of the parent molecule is a critical mechanistic event. The redox cycling of paraquat has two potentially important consequences relevant to the development of toxicity: generation of activated oxygen (e.g., superoxide anion, hydrogen perioxide, hydroxyl radical) which is highly reactive to cellular macromolecules; and/or oxidation of reducing equivalents (e.g., NADPH, reduced glutathione) necessary for normal cell function. Paraquat-induced pulmonary toxicity, therefore, is a potentially useful model for evaluation of oxidant mechanisms of toxicity. Furthermore, characterization of the consequences of intracellular redox cycling of xenobiotics will no doubt provide basic information regarding the role of this phenomena in the development of chemical toxicity. 105 references, 2 figures.

  16. Toxicity of common ions to marine organisms

    International Nuclear Information System (INIS)

    Pillard, D.A.; DuFresne, D.L.; Evans, J.

    1995-01-01

    Produced waters from oil and gas drilling operations are typically very saline, and these may cause acute toxicity to marine organisms due to osmotic imbalances as well as to an excess or deficiency of specific common ions. In order to better understand the relationship between toxicity and ion concentration, laboratory toxicity tests were conducted using mysid shrimp (Mysidopsis bahia), sheepshead minnow (Cyprinodon variegatus), and inland silverside (Menidia beryllina). For each species the ionic concentration of standard laboratory water was proportionally increased or decreased to produce test solutions with a range of salinities. Organisms were exposed for 48 hours. Individual ions (sodium, potassium, calcium, magnetsium, strontium, chloride, bromide, sulfate, bicarbonate, and borate) were also manipulated to examine individual ion toxicity. The three test species differ in their tolerance of salinity. Mysid shrimp show a marked decrease in survival at salinities less than approximately 5 ppt. Both fish species tolerated low salinity water, however, silversides were less tolerant of saline waters (salinity greater than 40 ppt). There were also significant differences in the responses of the organisms to different ions. The results show that the salinity of the test solution may play an important role in the responses of the organisms to the produced water effluent. Predictable toxicity/ion relationships developed in this study can be used to estimate whether toxicity in a produced water is a result of common ions, salinity, or some other unknown toxicant

  17. Nail toxicity induced by cancer chemotherapy.

    Science.gov (United States)

    Gilbar, Peter; Hain, Alice; Peereboom, Veta-Marie

    2009-09-01

    To provide a comprehensive literature review of chemotherapy-induced nail toxicity, including clinical presentation, implicated drugs and approaches for prevention and management. A search of MEDLINE and EMBASE (1966-2008) databases was conducted using the terms (and variations of the terms) antineoplastic agents, nails, nail toxicity, onycholysis, and paronychia. Bibliographies from selected articles were reviewed for appropriate references. The retrieved literature was reviewed to include all articles relevant to the clinical presentation, diagnosis, incidence, prevention, and treatment of chemotherapy-induced nail toxicity. Nail toxicity is a relatively uncommon adverse effect linked to a number of chemotherapeutic agents. Clinical presentation varies, depending on which nail structure is affected and the severity of the insult. Nail changes may involve all or some nails. Toxicity may be asymptomatic and limited to cosmetic concerns, however, more severe effects, involving pain and discomfort can occur. Taxanes and anthracyclines are the antineoplastic drug groups most commonly implicated. It is suggested that the administration schedule may influence the incidence of nail abnormalities, for example reported cases linked to the weekly administration of paclitaxel.Before instituting chemotherapy, patients should be educated regarding potential nail toxicities and strategies for prevention implemented. Management includes appropriate nail cutting, avoiding potential irritants, topical, or oral antimicrobials, and possibly cessation or dose reduction of the offending agent. Cryotherapy, through the application of frozen gloves or socks, has been beneficial in reducing docetaxel-induced nail toxicity and may be effective for other drugs.

  18. On the attenuation of the ambient seismic field

    International Nuclear Information System (INIS)

    Weemstra, C.

    2013-01-01

    Although myriad applications exploiting the ambient seismic field have been reported to date, comparatively little attention has been paid to its potential to resolve subsurface attenuation. The ambient seismic field, however, may ultimately prove itself an invaluable asset in constraining subsurface attenuation structure. Especially areas with dense seismometer coverage hold great potential. Moreover, since this coverage continues to grow, significant developments may await in the future. Subsurface structure in terms of attenuation is of great importance for many reasons. For example, knowledge of the attenuation structure may aid in predicting ground motions caused by future large earthquakes. From a scientific perspective, a great deal of new information may be extracted, potentially fostering research in related fields (e.g., geodynamics, hydrology). Both from an environmental and economic point of view, inversion of the ambient seismic wavefield for attenuation structure may in the future provide a means to image hydrocarbon reservoirs. In sufficiently diffuse wavefields, simple cross-correlation of long noise time series recorded by two receivers results in the response at one of the receivers as if there was a source at the position of the other. I present a case study that shows that thus retrieved surface waves can be used to recover attenuation beneath an array of ocean-bottom seismometers. Given the small aperture of the seismic survey, this is unprecedented. Unambiguous interpretation of recovered attenuation values is of major importance. Lack of understanding of the effect that preprocessing has on the amplitude of the noise cross-correlation prevents such unambiguous interpretation. I carefully examine the effect spectral whitening has on the noise cross-correlation. Emphasis is given to the dependence of the amplitudes on the length of the time windows employed in the cross-correlation procedure. Short time-window lengths may require an additional

  19. Assessing sediment contamination using six toxicity assays

    OpenAIRE

    Allen G. BURTON Jr.; Carolyn ROWLAND; Renato BAUDO; Monica BELTRAMI

    2001-01-01

    An evaluation of sediment toxicity at Lake Orta, Italy was conducted to compare a toxicity test battery of 6 assays and to evaluate the extent of sediment contamination at various sediment depths. Lake Orta received excessive loadings of copper and ammonia during the 1900’s until a large remediation effort was conducted in 1989-90 using lime addition. Since that time, the lake has shown signs of a steady recovery of biological communities. The study results showed acute toxicity still exists ...

  20. Computerized tomography in acute toxic encephalopathy

    International Nuclear Information System (INIS)

    Aoki, Nobuhiko; Kaneshi, Kunio; Mizuguchi, Masashi; Kurihara, Eiji.

    1983-01-01

    We experienced three cases of acute toxic encephalopathy, including a case of probable Reye syndrome, which had similar and unique CT findings in their acute stage; symmetrical low density area in the thalamus and the dentate nucleus, followed by changes in cerebellar hemispheres and around lateral ventricles. The CT findings, common to probable Reye syndrome and other acute toxic encephalopathy, may suggest the possibility of similar pathogenesis of brain damage in both disorders. The authors propose that present cases are a new subgroup in acute toxic encephalopathy, because of their similar and unique CT features. (author)