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Sample records for menadione enhances oxyradical

  1. Menadione enhances oxyradical formation in earthworm extracts: vulnerability of earthworms to quinone toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Osman, A.M.; Besten, P.J. den; Noort, P.C.M. van

    2003-10-08

    NAD(P)H-cytochrome c reductase activities have been determined in the earthworms, L. rubellus and A. chlorotica, extracts. Menadione (0.35 mM, maximum concentration tested) was found to stimulate the rates of NADPH- and NADH-dependent cytochrome c reduction by three- and twofold, respectively. Superoxide dismutase (SOD) inhibited completely this menadione-mediated stimulation, suggesting that {center_dot}O{sub 2}{sup -} is involved in the redox cycling of menadione. However, SOD had no effect on the basal activity (activity in the absence of quinone) in the case of NADH-dependent cytochrome c reduction, whereas it partially inhibited the basal activity of NADPH-cytochrome c reduction. This indicates direct electron transfer in the former case and the formation of superoxide anion in the latter. DT-diaphorase, measured as the dicumarol-inhibitable part of menadione reductase activity, was not detectable in the earthworms' extracts. In contrast, it was found that DT-diaphorase represents about 70% of the menadione reductase activities in the freshwater mussel, Dreissena polymorpha. The results of this work suggest that earthworms, compared with mussels, could be more vulnerable to oxidative stress from quinones due to lack, or very low level of DT-diaphorase, an enzyme considered to play a significant role in the detoxification of quinones. On the contrary, mussels have efficient DT-diaphorase, which catalyzes two-electron reduction of menadione directly to hydroquinone, thus circumventing the formation of semiquinone.

  2. Menadione enhances oxyradical formation in earthworm extracts: vulnerability of earthworms to quinone toxicity

    International Nuclear Information System (INIS)

    Osman, A.M.; Besten, P.J. den; Noort, P.C.M. van

    2003-01-01

    NAD(P)H-cytochrome c reductase activities have been determined in the earthworms, L. rubellus and A. chlorotica, extracts. Menadione (0.35 mM, maximum concentration tested) was found to stimulate the rates of NADPH- and NADH-dependent cytochrome c reduction by three- and twofold, respectively. Superoxide dismutase (SOD) inhibited completely this menadione-mediated stimulation, suggesting that ·O 2 - is involved in the redox cycling of menadione. However, SOD had no effect on the basal activity (activity in the absence of quinone) in the case of NADH-dependent cytochrome c reduction, whereas it partially inhibited the basal activity of NADPH-cytochrome c reduction. This indicates direct electron transfer in the former case and the formation of superoxide anion in the latter. DT-diaphorase, measured as the dicumarol-inhibitable part of menadione reductase activity, was not detectable in the earthworms' extracts. In contrast, it was found that DT-diaphorase represents about 70% of the menadione reductase activities in the freshwater mussel, Dreissena polymorpha. The results of this work suggest that earthworms, compared with mussels, could be more vulnerable to oxidative stress from quinones due to lack, or very low level of DT-diaphorase, an enzyme considered to play a significant role in the detoxification of quinones. On the contrary, mussels have efficient DT-diaphorase, which catalyzes two-electron reduction of menadione directly to hydroquinone, thus circumventing the formation of semiquinone

  3. Menadione.

    Science.gov (United States)

    Hassan, Ghada S

    2013-01-01

    This chapter includes the aspects of Menadione (vitamin K). The drug is synthesized by the use of itaconic acid obtained through Friedel-Craft condensation or by direct oxidation of the 2-methyl-1,4-naphthquinone. Vitamin K generally maintains healthy blood clotting and prevents excessive bleeding and hemorrhage, it is also important for maintaining healthy bone structure and for carbohydrate storage in the body. In addition, it is given to newborn babies born in hospitals to prevent the development of life-threatening bleeding caused by low prothrombin levels. The chapter discusses the drug metabolism and pharmacokinetics and presents various method of analysis of this drug such as compendial tests, electrochemical analysis, spectroscopic analysis, and chromatographic techniques of separation. It also discusses its physical properties such as solubility characteristics, X-ray powder diffraction pattern, and thermal methods of analysis. The chapter is concluded with a discussion on its biological properties such as activity, toxicity, and safety. Copyright © 2013 Elsevier Inc. All rights reserved.

  4. Menadione (vitamin K enhances the antibiotic activity of drugs by cell membrane permeabilization mechanism

    Directory of Open Access Journals (Sweden)

    Jacqueline C. Andrade

    2017-01-01

    Full Text Available Menadione, vitamin K3, belongs to the class of lipid-soluble vitamins and lipophilic substances as menadione cause disturbances in the bacterial membrane, resulting in damage to the fundamental elements for the integrity of the membrane, thus allowing increased permeability. Accordingly, the aim of this study was to evaluate in vitro the antibiotic-modifying activity of menadione in multiresistant strains of Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli, with a gradual increase in its subinhibitory concentration. In addition, menadione was compared with cholesterol and ergosterol for similarity in mechanism of drug modulatory action. Antibiotic-modifying activity and antibacterial effect were determined by the broth microdilution assay. Menadione, cholesterol and ergosterol showed modulatory activity at clinically relevant concentrations, characterizing them as modifiers of bacterial drug resistance, since they lowered the MIC of the antibiotics tested. This is the first report of the antibacterial activity of menadione and its potentiation of aminoglycosides against multiresistant bacteria.

  5. Oxyradical accumulation and rapid deterioration of soybean seeds due to field weathering.

    Science.gov (United States)

    Yadav, Sanjeev; Bhatia, V S; Guruprasad, K N

    2006-02-01

    The effect of field weathering on oxyradical accumulation and subsequent changes were studied in the seeds of soybean [Glycine max (L.) Merr.] cv. JS 71-05. Electron spin resonance (ESR) quantification of oxyradical revealed that field weathering plays an important role in acceleration of their accumulation. One week of weathering increased the accumulation of oxyradicals to almost 2-fold and triggered the deteriorative cascade, by enhancing the lipid peroxidation and membrane perturbation, leading to cell death in seed tissues and poor germinability and vigour of soybean seeds. Thus, the weather conditions at the time of physiological maturity to harvesting of crop are very crucial and the field weathering plays a critical role for the maintenance of seed quality.

  6. Complex formation between menadione and cetylethylmorpholinium ethosulfate: effect on uv photodegradation of menadione

    International Nuclear Information System (INIS)

    Kowarski, C.R.; Ghandi, H.I.

    1975-01-01

    The process of menadione photodegradation can be enhanced or diminished by other compounds. The presence of the quaternary ammonium compound cetylethylmorpholinium ethosulfate (I) in solutions of menadione was found to slow the rate of photodegradation by uv light (253.7 nm). The mechanism of this effect may be due to complex formation between menadione and I. Complex formation was demonstrated by a shift in the absorption peaks of menadione from 245 and 260 nm to 251.5 and 261.5 nm, respectively. The equilibrium constant of this complex was calculated to be 1.647 M

  7. Menadione Sodium Bisulphite (MSB) enhances the resistance response of tomato, leading to repel mollusc pests.

    Science.gov (United States)

    Carrillo-Perdomo, Estefanía; Jiménez-Arias, David; Aller, Ángel; Borges, Andrés A

    2016-05-01

    Snails and slugs are terrestrial gastropods representing an important biotic stress that adversely affects crop yields. These pests are typically controlled with molluscicides, which produce pollution and toxicity and further induce the evolution of resistance mechanisms, making pest management even more challenging. In our work, we have assessed the efficacy of two different plant defence activators, menadione sodium bisulphite (MSB) and 1,2,3-benzothiadiazole-7-thiocarboxylic acid S-methyl ester (BTH), as inducers of resistance mechanisms of the model plant for defence, Solanum lycopersicum, against the generalist mollusc Theba grasseti (Helicidae). The study was designed to test the feeding behaviour and choice of snails, and also to analyse the expression profile of different genes specifically involved in defence against herbivores and wounds. Our data suggest that, through the downregulation of the terpene volatile genes and the production of proteinase inhibitors, treated MSB plants may be less apparent to herbivores that use herbivore-induced plant volatiles for host location. By contrast, BTH was not effective in the treatment of the pest, probably owing to an antagonistic effect derived from the induction of both salicylic-acid-dependent and jasmonic-acid-dependent pathways. This information is crucial to determine the genetic basis of the choice of terrestrial gastropod herbivores in tomato, providing valuable insight into how the plant defence activators could control herbivore pests in plants. Our work not only reports for the first time the interaction between tomato and a mollusc pest but also presents the action of two plant defence inductors that seems to produce opposed responses by inducing resistance mechanisms through different defence pathways. © 2015 Society of Chemical Industry.

  8. Menadione 処理した Candida albicans ROS 生産機構の解析

    OpenAIRE

    上野, 将明; 小笠原, 綾子; 渡部, 俊彦; 三上, 健; 松本, 達二; ウエノ, ユキヒロ; オガサワラ, アヤコ; ワタナベ, トシユキ; ミカミ, タケシ; マツモト, タツジ; Yukihiro, UENO; Ayako, OGASAWARA; Toshihiko, WATANABE; Takeshi, MIKAMI; Tatsuji, MATSUMOTO

    2008-01-01

    Menadione shows anti Condida activity by promoting ROS production. However, the ROS production mechanism has not been clarifield. Thus, in this study, we studied thr relation between anti Candida activity of menadione and ROS production. Menadione inhibited the growth of C. albicans BWP17 strain, the growth of C. albicans JM02 strain was not inhibited. ROS production in C. albicans BWP17 strain was enhanced by addition of menadione. The ROS production in C. albicans JM02 strain was also enhan...

  9. Menadione serves as a substrate for P-glycoprotein: implication in chemosensitizing activity.

    Science.gov (United States)

    Oh, Seok-Jeong; Han, Hyo-Kyung; Kang, Keon-Wook; Lee, Young-Joo; Lee, Moo-Yeol

    2013-04-01

    Based on its chemosensitizing effect, we questioned whether menadione is an inhibitor or a substrate of P-glycoprotein (P-gp). To test this hypothesis, we assessed the effect of menadione on P-gp activity and examined the P-gp-dependency of cellular accumulation and cytotoxicity of menadione as well. Treatment with menadione resulted in the concentration-dependent increase of rhodamine 123 (Rh123) accumulation in P-gp-overexpressing MDCKII/MDR1 and NCI/ADR-RES cells, suggesting that menadione inhibits Rh123 extrusion by P-gp. Compared with MDCKII or MCF-7, intracellular distribution of [(3)H]-menadione was significantly lower in MDCKII/MDR1 or NCI/ADR-RES cells, which could be restored by the P-gp inhibitors, verapamil and quinidine. Consistent with these results, MDCKII/MDR1 or NCI/ADR-RES cells were more resistant to the cytotoxicity of menadione than MDCKII or MCF-7 cells, respectively. Such resistance was abolished by the combined treatment of verapamil and quinidine in NCI/ADR-RES cells. Our study identified menadione as a substrate of P-gp, which presumably, acts as the mechanism for the chemosensitizing effect. Menadione may be a promising chemotherapeutic enhancer by its ability of circumventing drug resistance, in addition to its own anti-cancer activity.

  10. Oxyradicals and PSII activity in maize leaves in the absence of UV ...

    Indian Academy of Sciences (India)

    2012-08-13

    Aug 13, 2012 ... UV radiation as compared to the leaves of the plants grown under UV exclusion filters. Smaller amount ... and hydrogen peroxide (H2O2), which can cause oxidative ... the production of oxyradicals and the extent of damage to.

  11. Measurement of menadione in urine by HPLC.

    Science.gov (United States)

    Al Rajabi, Ala; Peterson, James; Choi, Sang-Woon; Suttie, John; Barakat, Susan; Booth, Sarah L

    2010-09-15

    Menadione is a metabolite of vitamin K that is excreted in urine. A high performance liquid chromatography (HPLC) method using a C(30) column, post-column zinc reduction and fluorescence detection was developed to measure urinary menadione. The mobile phase was composed of 95% methanol with 0.55% aqueous solution and 5% DI H(2)O. Menaquinone-2 (MK-2) was used as an internal standard. The standard calibration curve was linear with a correlation coefficient (R(2)) of 0.999 for both menadione and MK-2. The lower limit of quantification (LLOQ) was 0.3pmole menadione/mL urine. Sample preparation involved hydrolysis of menadiol conjugates and oxidizing the released menadiol to menadione. Using this method, urinary menadione was shown to increase in response to 3 years of phylloquinone supplementation. This HPLC method is a sensitive and reproducible way to detect menadione in urine. Copyright (c) 2010 Elsevier B.V. All rights reserved.

  12. High glutamate attenuates S100B and LDH outputs from rat cortical slices enhanced by either oxygen-glucose deprivation or menadione.

    Science.gov (United States)

    Demircan, Celaleddin; Gül, Zülfiye; Büyükuysal, R Levent

    2014-07-01

    One hour incubation of rat cortical slices in a medium without oxygen and glucose (oxygen-glucose deprivation, OGD) increased S100B release to 6.53 ± 0.3 ng/ml/mg protein from its control value of 3.61 ± 0.2 ng/ml/mg protein. When these slices were then transferred to a medium containing oxygen and glucose (reoxygenation, REO), S100B release rose to 344 % of its control value. REO also caused 192 % increase in lactate dehydrogenase (LDH) leakage. Glutamate added at millimolar concentration into the medium decreased OGD or REO-induced S100B release and REO-induced LDH leakage. Alpha-ketoglutarate, a metabolic product of glutamate, was found to be as effective as glutamate in decreasing the S100B and LDH outputs. Similarly lactate, 2-ketobutyrate and ethyl pyruvate, a lipophilic derivative of pyruvate, also exerted a glutamate-like effect on S100B and LDH outputs. Preincubation with menadione, which produces H2O2 intracellularly, significantly increased S100B and LDH levels in normoxic medium. All drugs tested in the present study, with the exception of pyruvate, showed a complete protection against menadione preincubation. Additionally, each OGD-REO, menadione or H2O2-induced mitochondrial energy impairments determined by 2,3,5-triphenyltetrazolium chloride (TTC) staining and OGD-REO or menadione-induced increases in reactive oxygen substances (ROS) determined by 2,7-dichlorofluorescin diacetate (DCFH-DA) were also recovered by glutamate. Interestingly, H2O2-induced increase in fluorescence intensity derived from DCFH-DA in a slice-free physiological medium was attenuated significantly by glutamate and alpha-keto acids. All these drug actions support the conclusion that high glutamate, such as alpha-ketoglutarate and other keto acids, protects the slices against OGD- and REO-induced S100B and LDH outputs probably by scavenging ROS in addition to its energy substrate metabolite property.

  13. Menadione stress in Saccharomyces cerevisiae strains deficient in the glutathione transferases.

    Science.gov (United States)

    Castro, F A V; Herdeiro, R S; Panek, A D; Eleutherio, E C A; Pereira, M D

    2007-02-01

    Using S. cerevisiae as a eukaryotic cell model we have analyzed the involvement of both glutathione transferase isoforms, Gtt1 and Gtt2, in constitutive resistance and adaptive response to menadione, a quinone which can exert its toxicity as redox cycling and/or electrophiles. The detoxification properties, of these enzymes, have also been analyzed by the appearance of S-conjugates in the media. Direct exposure to menadione (20 mM/60 min) showed to be lethal for cells deficient on both Gtt1 and Gtt2 isoforms. However, after pre-treatment with a low menadione concentration, cells deficient in Gtt2 displayed reduced ability to acquire tolerance when compared with the control and the Gtt1 deficient strains. Analyzing the toxic effects of menadione we observed that the gtt2 mutant showed no reduction in lipid peroxidation levels. Moreover, measuring the levels of intracellular oxidation during menadione stress we have shown that the increase of this oxidative stress parameter was due to the capacity menadione possesses in generating reactive oxygen species (ROS) and that both GSH and Gtt2 isoform were required to enhance ROS production. Furthermore, the efflux of the menadione-GSH conjugate, which is related with detoxification of xenobiotic pathways, was not detected in the gtt2 mutant. Taken together, these results suggest that acquisition of tolerance against stress generated by menadione and the process of detoxification through S-conjugates are dependent upon Gtt2 activity. This assessment was corroborated by the increase of GTT2 expression, and not of GTT1, after menadione treatment.

  14. The effect of bicarbonate on menadione-induced redox cycling and cytotoxicity: potential involvement of the carbonate radical.

    Science.gov (United States)

    Aljuhani, Naif; Michail, Karim; Karapetyan, Zubeida; Siraki, Arno G

    2013-10-01

    We have investigated the effect of NaHCO3 on menadione redox cycling and cytotoxicity. A cell-free system utilized menadione and ascorbic acid to catalyze a redox cycle, and we utilized murine hepatoma (Hepa 1c1c7) cells for in vitro experiments. Experiments were performed using low (2 mmol/L) and physiological (25 mmol/L) levels of NaHCO3 in buffer equilibrated to physiological pH. Using oximetry, ascorbic acid oxidation, and ascorbyl radical detection, we found that menadione redox cycling was enhanced by NaHCO3. Furthermore, Hepa 1c1c7 cells treated with menadione demonstrated cytotoxicity that was significantly increased with physiological concentrations of NaHCO3 in the media, compared with low levels of NaHCO3. Interestingly, the inhibition of superoxide dismutase (SOD) with 2 different metal chelators was associated with a protective effect against menadione cytotoxicity. Using isolated protein, we found a significant increase in protein carbonyls with menadione-ascorbate-SOD with physiological NaHCO3 levels; low NaHCO3 or SOD-free reactions produced lower levels of protein carbonyls. In conclusion, these findings suggest that the hydrogen peroxide generated by menadione redox cycling together with NaHCO3-CO2 are potential substrates for SOD peroxidase activity that can lead to carbonate-radical-enhanced cytotoxicity. These findings demonstrate the importance of NaHCO3 in menadione redox cycling and cytotoxicity.

  15. Different characteristics between menadione and menadione sodium bisulfite as redox mediator in yeast cell suspension

    OpenAIRE

    Yamashoji, Shiro

    2016-01-01

    Menadione promoted the production of active oxygen species (AOS) in both yeast cell suspension and the crude enzymes from the cells, but menadione sodium bisulfite (MSB) had little effect on the production of AOS in the cell suspension. MSB kept the stable increase in the electron transfer from intact yeast cells to anode compared to menadione, but the electron transfer promoted by MSB was inhibited in permeabilized yeast cell suspension. Menadione promoted oxidation of NAD(P)H much faster th...

  16. SATB2 participates in regulation of menadione-induced apoptotic insults to osteoblasts.

    Science.gov (United States)

    Wei, Jyh-Ding; Lin, Yi-Ling; Tsai, Cheng-Hsiu; Shieh, Hui-Shan; Lin, Pei-I; Ho, Wei-Pin; Chen, Ruei-Ming

    2012-07-01

    Special AT-rich sequence binding protein 2 (SATB2), a nuclear matrix attachment region-binding protein, can regulate embryonic development, cell differentiation, and cell survival. Previous studies showed that SATB2 is involved in osteoblast differentiation and skeletal development. In this study, we evaluated the role of SATB2 in oxidative stress-induced apoptotic insults to human osteoblast-like MG63 cells and mouse MC3T3-E1 cells. Exposure of MG63 cells to menadione increased intracellular reactive oxygen species levels in a concentration- and time-dependent manner. Simultaneously, menadione-induced oxidative stress triggered cell shrinkage and decreased cell viability. In addition, treatment of MG63 cells with menadione time-dependently decreased the mitochondrial membrane potential but enhanced caspase-3 activity. As a result, menadione-induced DNA fragmentation and cell apoptosis. As to the mechanism, exposure of MG63 cells to menadione amplified SATB2 messenger (m)RNA and protein expression in a time-dependent manner. Knockdown of translation of SATB2 mRNA using RNA interference led to chromatin disruption and nuclear damage. When MG63 cells and MC3T3-E1 cells were treated with SATB2 small interfering RNA, menadione-induced cell apoptosis was increased. We conclude that menadione causes oxidative stress in human osteoblasts and induces cellular apoptosis via a mitochondrion-caspase protease pathway. In addition, SATB2 may play a crucial role in protecting against oxidative stress-induced osteoblast apoptosis. Copyright © 2012 Orthopaedic Research Society.

  17. 21 CFR 573.620 - Menadione dimethylpyrimidinol bisulfite.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Menadione dimethylpyrimidinol bisulfite. 573.620... ANIMALS Food Additive Listing § 573.620 Menadione dimethylpyrimidinol bisulfite. The food additive, menadione dimethylpyrimidinol bisulfite, may be safely used in accordance with the following conditions: (a...

  18. The induction of menadione stress tolerance in the marine microalga, Dunaliella viridis, through cold pretreatment and modulation of the ascorbate and glutathione pools.

    Science.gov (United States)

    Madadkar Haghjou, Maryam; Colville, Louise; Smirnoff, Nicholas

    2014-11-01

    The effect of cold pretreatment on menadione tolerance was investigated in the cells of the marine microalga, Dunaliella viridis. In addition, the involvement of ascorbate and glutathione in the response to menadione stress was tested by treating cell suspensions with l-galactono-1,4-lactone, an ascorbate precursor, and buthionine sulfoximine, an inhibitor of glutathione synthesis. Menadione was highly toxic to non cold-pretreated cells, and caused a large decrease in cell number. Cold pretreatment alleviated menadione toxicity and cold pretreated cells accumulated lower levels of reactive oxygen species, and had enhanced antioxidant capacity due to increased levels of β-carotene, reduced ascorbate and total glutathione compared to non cold-pretreated cells. Cold pretreatment also altered the response to l-galactono-1,4-lactone and buthionine sulfoximine treatments. Combined l-galactono-1,4-lactone and menadione treatment was lethal in non-cold pretreated cells, but in cold-pretreated cells it had a positive effect on cell numbers compared to menadione alone. Overall, exposure of Dunaliella cells to cold stress enhanced tolerance to subsequent oxidative stress induced by menadione. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  19. Oxidative stress by ascorbate/menadione association kills K562 human chronic myelogenous leukaemia cells and inhibits its tumour growth in nude mice.

    Science.gov (United States)

    Verrax, Julien; Stockis, Julie; Tison, Aurélie; Taper, Henryk S; Calderon, Pedro Buc

    2006-09-14

    The effect of oxidative stress induced by the ascorbate/menadione-redox association was examined in K562 cells, a human erythromyeloid leukaemia cell line. Our results show that ascorbate enhances menadione redox cycling, leading to the formation of intracellular reactive oxygen species (as shown by dihydrorhodamine 123 oxidation). The incubation of cells in the presence of both ascorbate/menadione and aminotriazole, a catalase inhibitor, resulted in a strong decrease of cell survival, reinforcing the role of H(2)O(2) as the main oxidizing agent killing K562 cells. This cell death was not caspase-3-dependent. Indeed, neither procaspase-3 and PARP were processed and only a weak cytochrome c release was observed. Moreover, we observed only 23% of cells with depolarized mitochondria. In ascorbate/menadione-treated cells, DNA fragmentation was observed without any sign of chromatin condensation (DAPI and TUNEL tests). The cell demise by ascorbate/menadione is consistent with a necrosis-like cell death confirmed by both cytometric profile of annexin-V/propidium iodide labeled cells and by light microscopy examination. Finally, we showed that a single i.p. administration of the association of ascorbate and menadione is able to inhibit the growth of K562 cells by about 60% (in both tumour size and volume) in an immune-deficient mice model. Taken together, these results reinforced our previous claims about a potential application of the ascorbate/menadione association in cancer therapy.

  20. Menadione Suppresses Benzo(αpyrene-Induced Activation of Cytochromes P450 1A: Insights into a Possible Molecular Mechanism.

    Directory of Open Access Journals (Sweden)

    Yulia A Sidorova

    Full Text Available Oxidative reactions that are catalyzed by cytochromes P450 1A (CYP1A lead to formation of carcinogenic derivatives of arylamines and polycyclic aromatic hydrocarbons (PAHs, such as the widespread environmental pollutant benzo(αpyrene (BP. These compounds upregulate CYP1A at the transcriptional level via an arylhydrocarbon receptor (AhR-dependent signaling pathway. Because of the involvement of AhR-dependent genes in chemically induced carcinogenesis, suppression of this signaling pathway could prevent tumor formation and/or progression. Here we show that menadione (a water-soluble analog of vitamin K3 inhibits BP-induced expression and enzymatic activity of both CYP1A1 and CYP1A2 in vivo (in the rat liver and BP-induced activity of CYP1A1 in vitro. Coadministration of BP and menadione reduced DNA-binding activity of AhR and increased DNA-binding activity of transcription factors Oct-1 and CCAAT/enhancer binding protein (C/EBP, which are known to be involved in negative regulation of AhR-dependent genes, in vivo. Expression of another factor involved in downregulation of CYP1A-pAhR repressor (AhRR-was lower in the liver of the rats treated with BP and menadione, indicating that the inhibitory effect of menadione on CYP1A is not mediated by this protein. Furthermore, menadione was well tolerated by the animals: no signs of acute toxicity were detected by visual examination or by assessment of weight gain dynamics or liver function. Taken together, our results suggest that menadione can be used in further studies on animal models of chemically induced carcinogenesis because menadione may suppress tumor formation and possibly progression.

  1. Menadione Suppresses Benzo(α)pyrene-Induced Activation of Cytochromes P450 1A: Insights into a Possible Molecular Mechanism.

    Science.gov (United States)

    Sidorova, Yulia A; Perepechaeva, Maria L; Pivovarova, Elena N; Markel, Arkady L; Lyakhovich, Vyacheslav V; Grishanova, Alevtina Y

    2016-01-01

    Oxidative reactions that are catalyzed by cytochromes P450 1A (CYP1A) lead to formation of carcinogenic derivatives of arylamines and polycyclic aromatic hydrocarbons (PAHs), such as the widespread environmental pollutant benzo(α)pyrene (BP). These compounds upregulate CYP1A at the transcriptional level via an arylhydrocarbon receptor (AhR)-dependent signaling pathway. Because of the involvement of AhR-dependent genes in chemically induced carcinogenesis, suppression of this signaling pathway could prevent tumor formation and/or progression. Here we show that menadione (a water-soluble analog of vitamin K3) inhibits BP-induced expression and enzymatic activity of both CYP1A1 and CYP1A2 in vivo (in the rat liver) and BP-induced activity of CYP1A1 in vitro. Coadministration of BP and menadione reduced DNA-binding activity of AhR and increased DNA-binding activity of transcription factors Oct-1 and CCAAT/enhancer binding protein (C/EBP), which are known to be involved in negative regulation of AhR-dependent genes, in vivo. Expression of another factor involved in downregulation of CYP1A-pAhR repressor (AhRR)-was lower in the liver of the rats treated with BP and menadione, indicating that the inhibitory effect of menadione on CYP1A is not mediated by this protein. Furthermore, menadione was well tolerated by the animals: no signs of acute toxicity were detected by visual examination or by assessment of weight gain dynamics or liver function. Taken together, our results suggest that menadione can be used in further studies on animal models of chemically induced carcinogenesis because menadione may suppress tumor formation and possibly progression.

  2. Menadione-induced DNA fragmentation without 8-hydroxy-2'-deoxyguanosine formation in isolated rat hepatocytes

    DEFF Research Database (Denmark)

    Fischer-Nielsen, Anne; Corcoran, George B.; Poulsen, Henrik E.

    1995-01-01

    Farmakologi, frie iltradikaler, menadion, DNA fragmentering, rotteleverceller, oksidativ DNA skade......Farmakologi, frie iltradikaler, menadion, DNA fragmentering, rotteleverceller, oksidativ DNA skade...

  3. Inhibition of PTEN and activation of Akt by menadione

    OpenAIRE

    Yoshikawa, Kyoko; Nigorikawa, Kiyomi; Tsukamoto, Mariko; Tamura, Namiko; Hazeki, Kaoru; Hazeki, Osamu

    2007-01-01

    Menadione (vitamin K3) has been shown to activate Erk in several cell lines. This effect has been shown to be due to the activation of EGF receptors (EGFR) as a result of inhibition of some protein tyrosine phosphatases. In the present study, we examined the effects of menadione on Akt in Chinese hamster ovary cells. The phosphorylation of Akt by menadione was not inhibited by AG1478, an inhibitor of EGFR. Menadione inhibited the lipid phosphatase activity of PTEN in a cell-free system. In an...

  4. Biological effects of menadione photochemistry: effects of menadione on biological systems may not involve classical oxidant production.

    OpenAIRE

    McCormick, M L; Denning, G M; Reszka, K J; Bilski, P; Buettner, G R; Rasmussen, G T; Railsback, M A; Britigan, B E

    2000-01-01

    Because cell-mediated reduction of menadione leads to the generation of reactive oxygen species (ROS), this quinone is widely used to investigate the effects of ROS on cellular functions. We report that A549 human lung epithelial cells exposed to menadione demonstrate a dose-dependent increase in both intracellular calcium ([Ca(2+)](i)) and ROS formation. The concentrations of menadione required to initiate these two events are markedly different, with ROS detection requiring higher levels of...

  5. 21 CFR 573.625 - Menadione nicotinamide bisulfite.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Menadione nicotinamide bisulfite. 573.625 Section 573.625 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... ANIMALS Food Additive Listing § 573.625 Menadione nicotinamide bisulfite. The food additive may be safely...

  6. Menadione inhibits MIBG uptake in two neuroendocrine cell lines

    NARCIS (Netherlands)

    Cornelissen, J.; Tytgat, G. A.; van den Brug, M.; van Kuilenburg, A. B.; Voûte, P. A.; van Gennip, A. H.

    1997-01-01

    In this paper we report on our studies of the effect of menadione on the uptake of MIBG in the neuroendocrine cell lines PC12 and SK-N-SH. Menadione inhibits the uptake of MIBG in both cell lines in a dose-dependent manner. Inhibition of MIBG uptake is most pronounced in the PC12 cell line.

  7. Menadione metabolism to thiodione in hepatoblastoma by scanning electrochemical microscopy

    Science.gov (United States)

    Mauzeroll, Janine; Bard, Allen J.; Owhadian, Omeed; Monks, Terrence J.

    2004-01-01

    The cytotoxicity of menadione on hepatocytes was studied by using the substrate generation/tip collection mode of scanning electrochemical microscopy by exposing the cells to menadione and detecting the menadione-S-glutathione conjugate (thiodione) that is formed during the cellular detoxication process and is exported from the cell by an ATP-dependent pump. This efflux was electrochemically detected and allowed scanning electrochemical microscopy monitoring and imaging of single cells and groups of highly confluent live cells. Based on a constant flux model, ≈6 × 106 molecules of thiodione per cell per second are exported from monolayer cultures of Hep G2 cells. PMID:15601769

  8. The level of menadione redox-cycling in pancreatic β-cells is proportional to the glucose concentration: role of NADH and consequences for insulin secretion.

    Science.gov (United States)

    Heart, Emma; Palo, Meridith; Womack, Trayce; Smith, Peter J S; Gray, Joshua P

    2012-01-15

    Pancreatic β-cells release insulin in response to elevation of glucose from basal (4-7mM) to stimulatory (8-16mM) levels. Metabolism of glucose by the β-cell results in the production of low levels of reactive oxygen intermediates (ROI), such as hydrogen peroxide (H(2)O(2)), a newly recognized coupling factor linking glucose metabolism to insulin secretion. However, high and toxic levels of H(2)O(2) inhibit insulin secretion. Menadione, which produces H(2)O(2) via redox cycling mechanism in a dose-dependent manner, was investigated for its effect on β-cell metabolism and insulin secretion in INS-1 832/13, a rat β-cell insulinoma cell line, and primary rodent islets. Menadione-dependent redox cycling and resulting H(2)O(2) production under stimulatory glucose exceeded several-fold those reached at basal glucose. This was paralleled by a differential effect of menadione (0.1-10μM) on insulin secretion, which was enhanced at basal, but inhibited at stimulatory glucose. Redox cycling of menadione and H(2)O(2) formation was dependent on glycolytically-derived NADH, as inhibition of glycolysis and application of non-glycogenic insulin secretagogues did not support redox cycling. In addition, activity of plasma membrane electron transport, a system dependent in part on glycolytically-derived NADH, was also inhibited by menadione. Menadione-dependent redox cycling was sensitive to the NQO1 inhibitor dicoumarol and the flavoprotein inhibitor diphenylene iodonium, suggesting a role for NQO1 and other oxidoreductases in this process. These data may explain the apparent dichotomy between the stimulatory and inhibitory effects of H(2)O(2) and menadione on insulin secretion. Published by Elsevier Inc.

  9. Free cholesterol accumulation impairs antioxidant activities and aggravates apoptotic cell death in menadione-induced oxidative injury.

    Science.gov (United States)

    Lee, Waisin; Xu, Mingjing; Li, Yue; Gu, Yong; Chen, Jianping; Wong, Derek; Fung, Peter C W; Shen, Jiangang

    2011-10-01

    Although the relationship between hypercholesterolemia and oxidative stress has been extensively investigated, direct evidence regarding to the roles of cholesterol accumulation in the generations of reactive oxygen species (ROS) and apoptotic cell death under oxidative stress is lack. In this study, we investigated productions of superoxide anions (O(2)(-)) and nitric oxide (NO), and apoptotic cell death in wild type Chinese hamster ovary (CHO) cells and cholesterol accumulated CHO cells genetically and chemically. Oxidative stress was induced by menadione challenge. The results revealed that abundance of free cholesterol (FC) promoted menadione-induced O(2)(-) and NO productions. FC accumulation down-regulated eNOS expression but up-regulated NADPH oxidases, and inhibited the activities of superoxide dismutase (SOD) and catalase. Treatment of menadione increased the expressions of iNOS and qp91 phox, enhanced the activities of SOD and catalase in the wild-type CHO cells but inhibited the activity of glutathione peroxidase in the cholesterol accumulated CHO cells. Moreover, FC abundance promoted apoptotic cell death in these cells. Taken together, those results suggest that free cholesterol accumulation aggravates menadione-induced oxidative stress and exacerbates apoptotic cell death. Copyright © 2011 Elsevier Inc. All rights reserved.

  10. Inhibition of PTEN and activation of Akt by menadione.

    Science.gov (United States)

    Yoshikawa, Kyoko; Nigorikawa, Kiyomi; Tsukamoto, Mariko; Tamura, Namiko; Hazeki, Kaoru; Hazeki, Osamu

    2007-04-01

    Menadione (vitamin K(3)) has been shown to activate Erk in several cell lines. This effect has been shown to be due to the activation of EGF receptors (EGFR) as a result of inhibition of some protein tyrosine phosphatases. In the present study, we examined the effects of menadione on Akt in Chinese hamster ovary cells. The phosphorylation of Akt by menadione was not inhibited by AG1478, an inhibitor of EGFR. Menadione inhibited the lipid phosphatase activity of PTEN in a cell-free system. In an intact cell system, menadione inhibited the effect of transfected PTEN on Akt. Thus, one mechanism of its action was considered the accelerated activation of Akt through inhibition of PTEN. This was not the sole mechanism responsible for the EGFR-independent activation of Akt, because menadione attenuated the rate of Akt dephosphorylation even in PTEN-null PC3 cells. The decelerated inactivation of Akt, probably through inhibition of some tyrosine phosphatases, was considered another mechanism of its action.

  11. The level of menadione redox-cycling in pancreatic β-cells is proportional to the glucose concentration: Role of NADH and consequences for insulin secretion

    Energy Technology Data Exchange (ETDEWEB)

    Heart, Emma [Cellular Dynamics Program, Marine Biological Laboratory, Woods Hole, MA, 02543 (United States); Palo, Meridith; Womack, Trayce [Department of Science, United States Coast Guard Academy, New London, CT, 06320 (United States); Smith, Peter J.S. [Cellular Dynamics Program, Marine Biological Laboratory, Woods Hole, MA, 02543 (United States); Institute for Life Sciences, University of Southampton (United Kingdom); Gray, Joshua P., E-mail: Joshua.p.gray@uscga.edu [Cellular Dynamics Program, Marine Biological Laboratory, Woods Hole, MA, 02543 (United States); Department of Science, United States Coast Guard Academy, New London, CT, 06320 (United States)

    2012-01-15

    Pancreatic β-cells release insulin in response to elevation of glucose from basal (4–7 mM) to stimulatory (8–16 mM) levels. Metabolism of glucose by the β-cell results in the production of low levels of reactive oxygen intermediates (ROI), such as hydrogen peroxide (H{sub 2}O{sub 2}), a newly recognized coupling factor linking glucose metabolism to insulin secretion. However, high and toxic levels of H{sub 2}O{sub 2} inhibit insulin secretion. Menadione, which produces H{sub 2}O{sub 2} via redox cycling mechanism in a dose-dependent manner, was investigated for its effect on β-cell metabolism and insulin secretion in INS-1 832/13, a rat β-cell insulinoma cell line, and primary rodent islets. Menadione-dependent redox cycling and resulting H{sub 2}O{sub 2} production under stimulatory glucose exceeded several-fold those reached at basal glucose. This was paralleled by a differential effect of menadione (0.1–10 μM) on insulin secretion, which was enhanced at basal, but inhibited at stimulatory glucose. Redox cycling of menadione and H{sub 2}O{sub 2} formation was dependent on glycolytically-derived NADH, as inhibition of glycolysis and application of non-glycogenic insulin secretagogues did not support redox cycling. In addition, activity of plasma membrane electron transport, a system dependent in part on glycolytically-derived NADH, was also inhibited by menadione. Menadione-dependent redox cycling was sensitive to the NQO1 inhibitor dicoumarol and the flavoprotein inhibitor diphenylene iodonium, suggesting a role for NQO1 and other oxidoreductases in this process. These data may explain the apparent dichotomy between the stimulatory and inhibitory effects of H{sub 2}O{sub 2} and menadione on insulin secretion. -- Highlights: ► Menadione stimulation or inhibition of insulin secretion is dependent upon applied glucose levels. ► Menadione-dependent H{sub 2}O{sub 2} production is proportional to applied glucose levels. ► Quinone-mediated redox cycling

  12. The level of menadione redox-cycling in pancreatic β-cells is proportional to the glucose concentration: Role of NADH and consequences for insulin secretion

    International Nuclear Information System (INIS)

    Heart, Emma; Palo, Meridith; Womack, Trayce; Smith, Peter J.S.; Gray, Joshua P.

    2012-01-01

    Pancreatic β-cells release insulin in response to elevation of glucose from basal (4–7 mM) to stimulatory (8–16 mM) levels. Metabolism of glucose by the β-cell results in the production of low levels of reactive oxygen intermediates (ROI), such as hydrogen peroxide (H 2 O 2 ), a newly recognized coupling factor linking glucose metabolism to insulin secretion. However, high and toxic levels of H 2 O 2 inhibit insulin secretion. Menadione, which produces H 2 O 2 via redox cycling mechanism in a dose-dependent manner, was investigated for its effect on β-cell metabolism and insulin secretion in INS-1 832/13, a rat β-cell insulinoma cell line, and primary rodent islets. Menadione-dependent redox cycling and resulting H 2 O 2 production under stimulatory glucose exceeded several-fold those reached at basal glucose. This was paralleled by a differential effect of menadione (0.1–10 μM) on insulin secretion, which was enhanced at basal, but inhibited at stimulatory glucose. Redox cycling of menadione and H 2 O 2 formation was dependent on glycolytically-derived NADH, as inhibition of glycolysis and application of non-glycogenic insulin secretagogues did not support redox cycling. In addition, activity of plasma membrane electron transport, a system dependent in part on glycolytically-derived NADH, was also inhibited by menadione. Menadione-dependent redox cycling was sensitive to the NQO1 inhibitor dicoumarol and the flavoprotein inhibitor diphenylene iodonium, suggesting a role for NQO1 and other oxidoreductases in this process. These data may explain the apparent dichotomy between the stimulatory and inhibitory effects of H 2 O 2 and menadione on insulin secretion. -- Highlights: ► Menadione stimulation or inhibition of insulin secretion is dependent upon applied glucose levels. ► Menadione-dependent H 2 O 2 production is proportional to applied glucose levels. ► Quinone-mediated redox cycling is dependent on glycolysis

  13. Menadione-treated synaptosomes as a model for post-ischaemic neuronal damage.

    OpenAIRE

    White, E J; Clark, J B

    1988-01-01

    Menadione bisulphite increased endogenous oxygen-radical production by rat brain synaptosomes, as indicated by H2O2 generation. Increased oxygen-radical production was also demonstrated in synaptosomes prepared from menadione-treated rats and synaptosomes reoxygenated after an anoxic insult. Acetylcholine synthesis de novo was inhibited in synaptosomes incubated with menadione in vitro, in synaptosomes prepared from menadione-treated animals in vivo, and in depolarized post-anoxic synaptosome...

  14. Insulin-like growth factor-1 protects preimplantation embryos from anti-developmental actions of menadione.

    Science.gov (United States)

    Moss, James I; Pontes, Eduardo; Hansen, Peter James

    2009-11-01

    Menadione is a naphthoquinone used as a vitamin K source in animal feed that can generate reactive oxygen species (ROS) and cause apoptosis. Here, we examined whether menadione reduces development of preimplantation bovine embryos in a ROS-dependent process and tested the hypothesis that actions of menadione would be reduced by insulin-like growth factor-1 (IGF-1). Menadione caused a concentration-dependent decrease in the proportion of embryos that became blastocysts. All concentrations tested (1, 2.5, and 5.0 microM) inhibited development. Treatment with 100 ng/ml IGF-1 reduced the magnitude of the anti-developmental effects of the two lowest menadione concentrations. Menadione also caused a concentration-dependent increase in the percent of cells positive for the TUNEL reaction. The response was lower for IGF-1-treated embryos. The effects of menadione were mediated by ROS because (1) the anti-developmental effect of menadione was blocked by the antioxidants dithiothreitol and Trolox and (2) menadione caused an increase in ROS generation. Treatment with IGF-1 did not reduce ROS formation in menadione-treated embryos. In conclusion, concentrations of menadione as low as 1.0 muM can compromise development of bovine preimplantation embryos to the blastocyst stage of development in a ROS-dependent mechanism. Anti-developmental actions of menadione can be blocked by IGF-1 through effects downstream of ROS generation.

  15. Inhibition of prostaglandin synthesis after metabolism of menadione by cultured porcine endothelial cells

    International Nuclear Information System (INIS)

    Barchowsky, A.; Tabrizi, K.; Kent, R.S.; Whorton, A.R.

    1989-01-01

    We have examined the effects of menadione on porcine aortic endothelial cell prostaglandin synthesis. Addition of 1-20 microM menadione caused a dose- and time-dependent inhibition of stimulated prostaglandin synthesis with an IC50 of 5 microM at 15 min. Concentrations greater than 100 microM menadione were necessary to increase 51 Cr release from prelabeled cells. Recovery of enzyme inactivated by menadione required a 6-h incubation in 1% serum. In a microsomal preparation, menadione was shown to have no direct effect on conversion of arachidonic acid to prostaglandins. In intact cells menadione caused only a 40% inhibition of the conversion of PGH2 to prostacyclin. Enzymes involved in the incorporation and the release of arachidonic acid were not affected by menadione (20 microM, 15 min). Menadione undergoes oxidation/reduction reactions in intact cells leading to partial reduction of oxygen-forming, reactive oxygen species. In our cells menadione was found to increase KCN-resistant oxygen consumption. Further, an increased accumulation of H 2 O 2 was observed with a time course consistent with menadione-induced inhibition of prostaglandin synthesis. We conclude that menadione at sublethal doses caused inhibition of prostaglandin synthesis. The mechanism involves inactivation of PGH2 synthase by a reactive species resulting from metabolism of menadione by endothelial cells

  16. α-Tocopherol impact on oxy-radical induced free radical decomposition of DMSO: Spin trapping EPR and theoretical studies

    International Nuclear Information System (INIS)

    Jerzykiewicz, Maria; Cwielag-Piasecka, Irmina; Witwicki, Maciej; Jezierski, Adam

    2011-01-01

    Graphical abstract: α-Tocopherol inhibits the oxidation of ·CH 3 to ·OCH 3 . Display Omitted Highlights: → α-Tocopherol does not inhibit the oxidation of DMSO to ·CH 3 . → α-Tocopherol inhibits the oxidation of ·CH 3 to ·OCH 3 . → α-Tocopherol does not inhibit the oxidation of PBN. → The structures of observed spin adducts were theoretically confirmed. - Abstract: EPR spin trapping and theoretical methods such as density functional theory (DFT) as well as combined DFT and quadratic configuration interaction approach (DFT/QCISD) were used to identify the radicals produced in the reaction of oxy-radicals and dimethyl sulfoxide (DMSO) in the presence and absence of α-tocopherol. Additionally, the mixtures of α-tocopherol with linolenic acid and glyceryl trilinoleate as well as bioglycerols (glycerol fractions from biodiesel production) were tested. α-Tocopherol inhibited oxidation of the main decomposition product of DMSO, ·CH 3 to ·OCH 3 but did not prevent the transformation process of N-t-butyl-α-phenylnitrone (PBN) into 2-methyl-2-nitrosopropane (MNP). Theoretical investigations confirmed the structures of proposed spin adducts and allowed to correlate the EPR parameters observed in the experiment with the spin adducts electronic structure.

  17. {alpha}-Tocopherol impact on oxy-radical induced free radical decomposition of DMSO: Spin trapping EPR and theoretical studies

    Energy Technology Data Exchange (ETDEWEB)

    Jerzykiewicz, Maria, E-mail: Mariaj@wchuwr.pl [Faculty of Chemistry, Wroclaw University, 14 F. Joliot-Curie St., 50-383 Wroclaw (Poland); Cwielag-Piasecka, Irmina; Witwicki, Maciej; Jezierski, Adam [Faculty of Chemistry, Wroclaw University, 14 F. Joliot-Curie St., 50-383 Wroclaw (Poland)

    2011-05-26

    Graphical abstract: {alpha}-Tocopherol inhibits the oxidation of {center_dot}CH{sub 3} to {center_dot}OCH{sub 3}. Display Omitted Highlights: {yields} {alpha}-Tocopherol does not inhibit the oxidation of DMSO to {center_dot}CH{sub 3}. {yields} {alpha}-Tocopherol inhibits the oxidation of {center_dot}CH{sub 3} to {center_dot}OCH{sub 3}. {yields} {alpha}-Tocopherol does not inhibit the oxidation of PBN. {yields} The structures of observed spin adducts were theoretically confirmed. - Abstract: EPR spin trapping and theoretical methods such as density functional theory (DFT) as well as combined DFT and quadratic configuration interaction approach (DFT/QCISD) were used to identify the radicals produced in the reaction of oxy-radicals and dimethyl sulfoxide (DMSO) in the presence and absence of {alpha}-tocopherol. Additionally, the mixtures of {alpha}-tocopherol with linolenic acid and glyceryl trilinoleate as well as bioglycerols (glycerol fractions from biodiesel production) were tested. {alpha}-Tocopherol inhibited oxidation of the main decomposition product of DMSO, {center_dot}CH{sub 3} to {center_dot}OCH{sub 3} but did not prevent the transformation process of N-t-butyl-{alpha}-phenylnitrone (PBN) into 2-methyl-2-nitrosopropane (MNP). Theoretical investigations confirmed the structures of proposed spin adducts and allowed to correlate the EPR parameters observed in the experiment with the spin adducts electronic structure.

  18. Inhibition of prostaglandin synthesis after metabolism of menadione by cultured porcine endothelial cells.

    OpenAIRE

    Barchowsky, A; Tabrizi, K; Kent, R S; Whorton, A R

    1989-01-01

    We have examined the effects of menadione on porcine aortic endothelial cell prostaglandin synthesis. Addition of 1-20 microM menadione caused a dose- and time-dependent inhibition of stimulated prostaglandin synthesis with an IC50 of 5 microM at 15 min. Concentrations greater than 100 microM menadione were necessary to increase 51Cr release from prelabeled cells. Recovery of enzyme inactivated by menadione required a 6-h incubation in 1% serum. In a microsomal preparation, menadione was show...

  19. Menadione (Vitamin K3) decreases melanin synthesis through ERK activation in Mel-Ab cells.

    Science.gov (United States)

    Kim, Eun-Hyun; Kim, Myo-Kyoung; Yun, Hye-Young; Baek, Kwang Jin; Kwon, Nyoun Soo; Park, Kyoung-Chan; Kim, Dong-Seok

    2013-10-15

    Menadione is a synthetic vitamin K3 derivative. Here, we examined the effects of menadione on melanogenesis and its related signaling pathways. Our results showed that melanin content was significantly reduced after menadione treatment in a dose-dependent manner. However, menadione treatment did not reduce tyrosinase activity directly. Wnt signaling is known to play a major role in the control of melanin synthesis. Thus, we tested the effects of menadione treatment on GSK3β and β-catenin signaling, but found that menadione did not influence either of these signaling pathways. We also investigated changes in the phosphorylation of ERK, which is related to melanin regulation. These results indicated that menadione treatment led to the phosphorylation of ERK. Additionally, menadione treatment reduced both MITF and tyrosinase protein levels. Treatment with PD98059, a specific ERK pathway inhibitor, restored menadione-induced melanin reduction and also prevented MITF and tyrosinase downregulation by menadione. These results suggest that the hypopigmentary action of menadione is due to MITF and tyrosinase downregulation by ERK activation. © 2013 Elsevier B.V. All rights reserved.

  20. *NO and oxyradical metabolism in new cell lines of rat brain capillary endothelial cells forming the blood-brain barrier.

    Science.gov (United States)

    Blasig, I E; Giese, H; Schroeter, M L; Sporbert, A; Utepbergenov, D I; Buchwalow, I B; Neubert, K; Schönfelder, G; Freyer, D; Schimke, I; Siems, W E; Paul, M; Haseloff, R F; Blasig, R

    2001-09-01

    To investigate the relevance of *NO and oxyradicals in the blood-brain barrier (BBB), differentiated and well-proliferating brain capillary endothelial cells (BCEC) are required. Therefore, rat BCEC (rBCEC) were transfected with immortalizing genes. The resulting lines exhibited endothelial characteristics (factor VIII, angiotensin-converting enzyme, high prostacyclin/thromboxane release rates) and BBB markers (gamma-glutamyl transpeptidase, alkaline phosphatase). The control line rBCEC2 (mock transfected) revealed fibroblastoid morphology, less factor VIII, reduced gamma-glutamyl transpeptidase, weak radical defence, low prostanoid metabolism, and limited proliferation. Lines transfected with immortalizing genes (especially rBCEC4, polyoma virus large T antigen) conserved primary properties: epitheloid morphology, subcultivation with high proliferation rate under pure culture conditions, and powerful defence against reactive oxygen species (Mn-, Cu/Zn-superoxide dismutase, catalase, glutathione peroxidase, glutathione) effectively controlling radical metabolism. Only 100 microM H2O2 overcame this defence and stimulated the formation of eicosanoids similarly as in primary cells. Some BBB markers were expressed to a lower degree; however, cocultivation with astrocytes intensified these markers (e.g., alkaline phosphatase) and paraendothelial tightness, indicating induction of BBB properties. Inducible NO synthase was induced by a cytokine plus lipopolysaccharide mixture in all lines and primary cells, resulting in *NO release. Comparing the cell lines obtained, rBCEC4 are stable immortalized and reveal the best conservation of properties from primary cells, including enzymes producing or decomposing reactive species. These cells can be subcultivated in large amounts and, hence, they are suitable to study the role of radical metabolism in the BBB and in the cerebral microvasculature. Copyright 2001 Academic Press.

  1. Seasonal variability of metallothioneins, cytochrome P450, Bile metabolites and oxyradical metabolism in the European eel Anguilla anguilla L. (Anguillidae) and striped mullet Mugil cephalus L. (Mugilidae).

    Science.gov (United States)

    Gorbi, Stefania; Baldini, Chiara; Regoli, Francesco

    2005-07-01

    The European eel Anguilla anguilla (Anguillidae) and the striped mullet Mugil cephalus (Mugilidae) are typical inhabitants of Mediterranean brackish lagoons, and their utility as bioindicator organisms has already been suggested. The seasonal variability of several potential biomarkers was investigated during a field study carried out in the Orbetello lagoon (Tuscany, Italy). Organisms were sampled on a seasonal basis, and analyzed parameters included the levels of hepatic metallothioneins, the activity of cytochrome P450 1A (EROD), and the presence of biliary PAH metabolites. Special attention was also paid to antioxidant defenses, including catalase, glutathione peroxidases, glutathione reductase, glutathione S-transferases, and total glutathione concentration. Total Oxyradical Scavenging Capacity (TOSC-assay) was measured as an indication of the overall biological resistance to toxicity of different forms of oxyradicals (peroxynitrite, peroxyl and hydroxyl radicals). Obtained results suggest that natural variations of analyzed responses are associated with seasonality of both environmental and biological factors, mainly temperature and reproductive cycle which, however, have a different influence in these two species. Striped mullets exhibited the strongest variations in October when spawning occurs; eels are not influenced by a seasonal sexual maturation and showed more marked changes during the summer, likely related to the elevated seawater temperature and light irradiance in the lagoon. This study confirms the importance of characterizing seasonal variations and the influence of different factors on biological responses that can be used as biomarkers in monitoring programs.

  2. Saccharomyces cerevisiae has distinct adaptive responses to both hydrogen peroxide and menadione.

    OpenAIRE

    Jamieson, D J

    1992-01-01

    Treatment of Saccharomyces cerevisiae cells with low concentrations of either hydrogen peroxide or menadione (a superoxide-generating agent) induces adaptive responses which protect cells from the lethal effects of subsequent challenge with higher concentrations of these oxidants. Pretreatment with menadione is protective against cell killing by hydrogen peroxide; however, pretreatment with hydrogen peroxide is unable to protect cells from subsequent challenge with menadione. This suggests th...

  3. Selective activation of heme oxygenase-2 by menadione.

    Science.gov (United States)

    Vukomanovic, Dragic; McLaughlin, Brian E; Rahman, Mona N; Szarek, Walter A; Brien, James F; Jia, Zongchao; Nakatsu, Kanji

    2011-11-01

    While substantial progress has been made in elucidating the roles of heme oxygenases-1 (HO-1) and -2 (HO-2) in mammals, our understanding of the functions of these enzymes in health and disease is still incomplete. A significant amount of our knowledge has been garnered through the use of nonselective inhibitors of HOs, and our laboratory has recently described more selective inhibitors for HO-1. In addition, our appreciation of HO-1 has benefitted from the availability of tools for increasing its activity through enzyme induction. By comparison, there is a paucity of information about HO-2 activation, with only a few reports appearing in the literature. This communication describes our observations of the up to 30-fold increase in the in-vitro activation of HO-2 by menadione. This activation was due to an increase in Vmax and was selective, in that menadione did not increase HO-1 activity.

  4. Buffer modulation of menadione-induced oxidative stress in Saccharomyces cerevisiae.

    Science.gov (United States)

    Lushchak, Oleh V; Bayliak, Maria M; Korobova, Olha V; Levine, Rodney L; Lushchak, Volodymyr I

    2009-01-01

    The objective of this study was to compare, in vivo, the effects of bicarbonate and phosphate buffers on survival and menadione-induced oxidative stress in yeast cells. The latter were treated with different concentrations of menadione in the presence of these two buffers. At 25 mM concentration of buffers, menadione only slightly reduced yeast surviving; at 50 mM concentration, cell killing by menadione was much more pronounced in bicarbonate than in phosphate buffer. Although the content of protein carbonyl groups did not show development of oxidative stress under menadione-induced stress, inactivation of aconitase and decrease in glutathione level mirrored its induction. However, cellular glutathione and aconitase activity decrease did not correlate with yeast survival. In vitro, aconitase was more quickly inactivated in 50 mM carbonate, than in 50 mM phosphate buffer. The possible involvement of the carbonate radical in these processes is discussed.

  5. Menadione-induced DNA fragmentation without 8-oxo-2'-deoxyguanosine formation in isolated rat hepatocytes

    DEFF Research Database (Denmark)

    Fischer-Nielsen, A; Corcoran, G B; Poulsen, H E

    1995-01-01

    Menadione (2-methyl-1,4-naphthoquinone) induces oxidative stress in cells causing perturbations in the cytoplasm as well as nicking of DNA. The mechanisms by which DNA damage occurs are still unclear, but a widely discussed issue is whether menadione-generated reactive oxygen species (ROS) directly...... damage DNA. In the present study, we measured the effect of menadione on formation of 7,8-dihydro-8-oxo-2'-deoxyguanosine (8-oxodG), an index of oxidative DNA base modifications, and on DNA fragmentation. Isolated hepatocytes from phenobarbital-pretreated rats were exposed to menadione, 25-400 micro......M, for 15, 90 or 180 min with or without prior depletion of reduced glutathione (GSH) by diethyl maleate. Menadione caused profound GSH depletion and internucleosomal DNA fragmentation, which was demonstrated by a prominent fragmentation ladder on agarose gel electrophoresis. We found no oxidative...

  6. Effects of menadione, a reactive oxygen generator, on leukotriene secretion from RBL-2H3 cells.

    Science.gov (United States)

    Kawamura, Fumio; Nakanishi, Mamoru; Hirashima, Naohide

    2010-01-01

    Reactive oxygen species (ROS) are produced in various cells and affect many biological processes. We previously reported that 2-methyl-1,4-naphtoquinone (menadione) inhibited Ca(2+) influx from the extracellular medium and exocytosis evoked by antigen stimulation in the mast cell line, RBL-2H3. Mast cells release various inflammatory mediators such as leukotrienes (LTs) and cytokines in addition to the exocytotic secretion of histamine. In this study, we investigated the effects of menadione on LT release in RBL-2H3. Treatment of RBL cells with menadione inhibited LTC(4) secretion induced by antigen stimulation. To elucidate the mechanism of this inhibition, we examined the effects of menadione on the activation process of 5-lipoxygenase that is responsible for the synthesis of LTs from arachidonic acid. Menadione did not affect the phosophorylation of mitogen activated protein (MAP) kinases, extracellular signal-regulated kinase (ERK) and p38, which regulates phosphorylation of 5-lipoxygenase. However, menadione inhibited the translocation of 5-lipoxygenase from the cytoplasm to the nuclear membrane. Together with the result that LT secretion was severely impaired in the absence of extracellular Ca2(2+), it is suggested that ROS produced by menadione inhibited LT secretion through impaired Ca2(2+) influx and 5-lipoxygenase translocation to the nuclear membrane.

  7. Menadione triggers cell death through ROS-dependent mechanisms involving PARP activation without requiring apoptosis.

    Science.gov (United States)

    Loor, Gabriel; Kondapalli, Jyothisri; Schriewer, Jacqueline M; Chandel, Navdeep S; Vanden Hoek, Terry L; Schumacker, Paul T

    2010-12-15

    Low levels of reactive oxygen species (ROS) can function as redox-active signaling messengers, whereas high levels of ROS induce cellular damage. Menadione generates ROS through redox cycling, and high concentrations trigger cell death. Previous work suggests that menadione triggers cytochrome c release from mitochondria, whereas other studies implicate the activation of the mitochondrial permeability transition pore as the mediator of cell death. We investigated menadione-induced cell death in genetically modified cells lacking specific death-associated proteins. In cardiomyocytes, oxidant stress was assessed using the redox sensor RoGFP, expressed in the cytosol or the mitochondrial matrix. Menadione elicited rapid oxidation in both compartments, whereas it decreased mitochondrial potential and triggered cytochrome c redistribution to the cytosol. Cell death was attenuated by N-acetylcysteine and exogenous glutathione or by overexpression of cytosolic or mitochondria-targeted catalase. By contrast, no protection was observed in cells overexpressing Cu,Zn-SOD or Mn-SOD. Overexpression of antiapoptotic Bcl-X(L) protected against staurosporine-induced cell death, but it failed to confer protection against menadione. Genetic deletion of Bax and Bak, cytochrome c, cyclophilin D, or caspase-9 conferred no protection against menadione-induced cell death. However, cells lacking PARP-1 showed a significant decrease in menadione-induced cell death. Thus, menadione induces cell death through the generation of oxidant stress in multiple subcellular compartments, yet cytochrome c, Bax/Bak, caspase-9, and cyclophilin D are dispensable for cell death in this model. These studies suggest that multiple redundant cell death pathways are activated by menadione, but that PARP plays an essential role in mediating each of them. Copyright © 2010 Elsevier Inc. All rights reserved.

  8. Responsiveness of entomopathogenic fungi to menadione-induced oxidative stress.

    Science.gov (United States)

    Azevedo, Rosana F F; Souza, Roberta K F; Braga, Gilberto U L; Rangel, Drauzio E N

    2014-12-01

    Entomopathogenic fungi are predisposed to ROS induced by heat and UV-A radiation when outside the insect host. When inside the host, they are subject to phagocytic cells that generate ROS to eliminate invading pathogens. The oxidative stress tolerance of the entomopathogenic fungi Aschersonia aleyrodis (ARSEF 430 and 10276), Aschersonia placenta (ARSEF 7637), Beauveria bassiana (ARSEF 252), Isaria fumosorosea (ARSEF 3889), Lecanicillium aphanocladii (ARSEF 6433), Metarhizium acridum (ARSEF 324), Metarhizium anisopliae (ARSEF 5749), Metarhizium brunneum (ARSEF 1187 and ARSEF 5626), Metarhizium robertsii (ARSEF 2575), Tolypocladium cylindrosporum (ARSEF 3392), Tolypocladium inflatum (ARSEF 4877), and Simplicillium lanosoniveum (ARSEF 6430 and ARSEF 6651) was studied based on conidial germination on a medium supplemented with menadione. Conidial germination was evaluated 24 h after inoculation on potato dextrose agar (PDA) (control) or PDA supplemented with menadione. The two Aschersonia species (ARSEF 430, 7637, and 10276) were the most susceptible fungi, followed by the two Tolypocladium species (ARSEF 3392 and 4877) and the M. acridum (ARSEF 324). Metarhizium brunneum (ARSEF 5626) and M. anisopliae (ARSEF 5749) were the most tolerant isolates with MIC 0.28 mM. All fungal isolates, except ARSEF 5626 and ARSEF 5749, were not able to germinate at 0.20 mM. Copyright © 2014 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

  9. Pre-exposure to 50 Hz magnetic fields modifies menadione-induced genotoxic effects in human SH-SY5Y neuroblastoma cells.

    Directory of Open Access Journals (Sweden)

    Jukka Luukkonen

    Full Text Available BACKGROUND: Extremely low frequency (ELF magnetic fields (MF are generated by power lines and various electric appliances. They have been classified as possibly carcinogenic by the International Agency for Research on Cancer, but a mechanistic explanation for carcinogenic effects is lacking. A previous study in our laboratory showed that pre-exposure to ELF MF altered cancer-relevant cellular responses (cell cycle arrest, apoptosis to menadione-induced DNA damage, but it did not include endpoints measuring actual genetic damage. In the present study, we examined whether pre-exposure to ELF MF affects chemically induced DNA damage level, DNA repair rate, or micronucleus frequency in human SH-SY5Y neuroblastoma cells. METHODOLOGY/PRINCIPAL FINDINGS: Exposure to 50 Hz MF was conducted at 100 µT for 24 hours, followed by chemical exposure for 3 hours. The chemicals used for inducing DNA damage and subsequent micronucleus formation were menadione and methyl methanesulphonate (MMS. Pre-treatment with MF enhanced menadione-induced DNA damage, DNA repair rate, and micronucleus formation in human SH-SY5Y neuroblastoma cells. Although the results with MMS indicated similar effects, the differences were not statistically significant. No effects were observed after MF exposure alone. CONCLUSIONS: The results confirm our previous findings showing that pre-exposure to MFs as low as 100 µT alters cellular responses to menadione, and show that increased genotoxicity results from such interaction. The present findings also indicate that complementary data at several chronological points may be critical for understanding the MF effects on DNA damage, repair, and post-repair integrity of the genome.

  10. Pre-exposure to 50 Hz magnetic fields modifies menadione-induced genotoxic effects in human SH-SY5Y neuroblastoma cells.

    Science.gov (United States)

    Luukkonen, Jukka; Liimatainen, Anu; Höytö, Anne; Juutilainen, Jukka; Naarala, Jonne

    2011-03-23

    Extremely low frequency (ELF) magnetic fields (MF) are generated by power lines and various electric appliances. They have been classified as possibly carcinogenic by the International Agency for Research on Cancer, but a mechanistic explanation for carcinogenic effects is lacking. A previous study in our laboratory showed that pre-exposure to ELF MF altered cancer-relevant cellular responses (cell cycle arrest, apoptosis) to menadione-induced DNA damage, but it did not include endpoints measuring actual genetic damage. In the present study, we examined whether pre-exposure to ELF MF affects chemically induced DNA damage level, DNA repair rate, or micronucleus frequency in human SH-SY5Y neuroblastoma cells. Exposure to 50 Hz MF was conducted at 100 µT for 24 hours, followed by chemical exposure for 3 hours. The chemicals used for inducing DNA damage and subsequent micronucleus formation were menadione and methyl methanesulphonate (MMS). Pre-treatment with MF enhanced menadione-induced DNA damage, DNA repair rate, and micronucleus formation in human SH-SY5Y neuroblastoma cells. Although the results with MMS indicated similar effects, the differences were not statistically significant. No effects were observed after MF exposure alone. The results confirm our previous findings showing that pre-exposure to MFs as low as 100 µT alters cellular responses to menadione, and show that increased genotoxicity results from such interaction. The present findings also indicate that complementary data at several chronological points may be critical for understanding the MF effects on DNA damage, repair, and post-repair integrity of the genome.

  11. Effects of dietary menadione on the activity of antioxidant enzymes in abalone, Haliotis discus hannai Ino

    Science.gov (United States)

    Fu, Jinghua; Xu, Wei; Mai, Kangsen; Zhang, Wenbing; Feng, Xiuni; Liufu, Zhiguo

    2012-01-01

    A 240-day growth experiment in a re-circulating water system was conducted to investigate the effects of dietary menadione on the growth and antioxidant responses of abalone Haliotis discus hannai Ino. Triplicate groups of juvenile abalone (initial weight: 1.19 ± 0.01 g; shell length: 19.23 ± 0.01 mm) were fed to satiation with 3 semi-purified diets containing 0, 10, and 1 000 mg menadione sodium bisulfite (MSB)/kg, respectively. Results show that there were no significant differences in the rate of weight gain or in the daily increment in shell length of abalone among different treatments. Activities of superoxide dismutase (SOD), glutathione peroxidase (GPX), glutathione S-transferase (GST) and glutathione reductase (GR) in viscera were significantly decreased with dietary menadione. However, activities of these enzymes except for GPX in muscle were increased. Therefore, antioxidant responses of abalone were increased in muscle and decreased in viscera by dietary menadione.

  12. The phosphatase inhibitor menadione (vitamin K3) protects cells from EGFR inhibition by erlotinib and cetuximab.

    Science.gov (United States)

    Perez-Soler, Roman; Zou, Yiyu; Li, Tianhong; Ling, Yi He

    2011-11-01

    Skin toxicity is the main side effect of epidermal growth factor receptor (EGFR) inhibitors, often leading to dose reduction or discontinuation. We hypothesized that phosphatase inhibition in the skin keratinocytes may prevent receptor dephosphorylation caused by EGFR inhibitors and be used as a new potential strategy for the prevention or treatment of this side effect. Menadione (Vitamin K3) was used as the prototype compound to test our hypothesis. HaCat human skin keratinocyte cells and A431 human squamous carcinoma cells were used. EGFR inhibition was measured by Western blotting and immunofluorescence. Phosphatase inhibition and reactive oxygen species (ROS) generation were measured by standard ELISA and fluorescence assays. Menadione caused significant and reversible EGFR activation in a dose-dependent manner starting at nontoxic concentrations. EGFR activation by menadione was associated with reversible protein tyrosine phosphatase inhibition, which seemed to be mediated by ROS generation as exposure to antioxidants prevented both menadione-induced ROS generation and phosphatase inhibition. Short-term coincubation of cells with nontoxic concentrations of menadione and the EGFR inhibitors erlotinib or cetuximab prevented EGFR dephosphorylation. Seventy-two-hour coincubation of cells with the highest nontoxic concentration of menadione and erlotinib provided for a fourfold cell growth inhibitory protection in HaCat human keratinocyte cells. Menadione at nontoxic concentrations causes EGFR activation and prevents EGFR dephosphorylation by erlotinib and cetuximab. This effect seems to be mediated by ROS generation and secondary phosphatase inhibition. Mild oxidative stress in skin keratinocytes by topical menadione may protect the skin from the toxicity secondary to EGFR inhibitors without causing cytotoxicity. ©2011 AACR

  13. Scanning electrochemical microscopy of menadione-glutathione conjugate export from yeast cells

    Science.gov (United States)

    Mauzeroll, Janine; Bard, Allen J.

    2004-01-01

    The uptake of menadione (2-methyl-1,4-naphthoquinone), which is toxic to yeast cells, and its expulsion as a glutathione complex were studied by scanning electrochemical microscopy. The progression of the in vitro reaction between menadione and glutathione was monitored electrochemically by cyclic voltammetry and correlated with the spectroscopic (UV–visible) behavior. By observing the scanning electrochemical microscope tip current of yeast cells suspended in a menadione-containing solution, the export of the conjugate from the cells with time could be measured. Similar experiments were performed on immobilized yeast cell aggregates stressed by a menadione solution. From the export of the menadione-glutathione conjugate detected at a 1-μm-diameter electrode situated 10 μm from the cells, a flux of about 30,000 thiodione molecules per second per cell was extracted. Numerical simulations based on an explicit finite difference method further revealed that the observation of a constant efflux of thiodione from the cells suggested the rate was limited by the uptake of menadione and that the efflux through the glutathione-conjugate pump was at least an order of magnitude faster. PMID:15148374

  14. Apoptosis inducing factor (AIF) mediates lethal redox stress induced by menadione.

    Science.gov (United States)

    Wiraswati, Hesti Lina; Hangen, Emilie; Sanz, Ana Belén; Lam, Ngoc-Vy; Reinhardt, Camille; Sauvat, Allan; Mogha, Ariane; Ortiz, Alberto; Kroemer, Guido; Modjtahedi, Nazanine

    2016-11-22

    Mitochondrial apoptosis inducing factor (AIF) is a redox-active enzyme that participates to the biogenesis/maintenance of complex I of the respiratory chain, yet also contributes to catabolic reactions in the context of regulated cell death when AIF translocates to the cytosol and to the nucleus. Here we explore the contribution of AIF to cell death induced by menadione (2-methyl-1,4-naphtoquinone; also called vitamin K3) in conditions in which this pro-oxidant does not cause the mitochondrial release of AIF, yet causes caspase-independent cell killing. Depletion of AIF from human cancer cells reduced the cytotoxicity of menadione. This cytoprotective effect was accompanied by the maintenance of high levels of reduced glutathione (GSH), which are normally depleted by menadione. In addition, AIF depletion reduced the arylation of cellular proteins induced by menadione. This menadione-triggered arylation, which can be measured by a fluorescence assay, is completely suppressed by addition of exogenous glutathione or N-acetyl cysteine. Complex I inhibition by Rotenone did not mimic the cytoprotective action of AIF depletion. Altogether, these results are compatible with the hypothesis that mitochondrion-sessile AIF facilitates lethal redox cycling of menadione, thereby precipitating protein arylation and glutathione depletion.

  15. In Vivo Anti-estrogenic Effects of Menadione on Hepatic Estrogen-responsive Gene Expression in Male Medaka (Oryzias latipes)

    OpenAIRE

    Yamaguchi, Akemi; Kohra, Shinya; Ishibashi, Hiroshi; Arizono, Koji; Tominaga, Nobuaki

    2008-01-01

    Menadione, a synthetic vitamin K3, exhibits anti-estrogenic activity on in vitro assay. However, the in vivo anti-estrogenic effects of menadione have not been determined, while correlations between biological effects and structural changes are unclear. Thus, we investigated the in vivo anti-estrogenic activity of menadione under fluorescent light and dark conditions. Suppression of the hepatic estrogen response genes vitellogenin1 (VTG1), VTG2 and estrogen receptor-α (ER-α) was used as an in...

  16. Role of glycolysis inhibition and poly(ADP-ribose) polymerase activation in necrotic-like cell death caused by ascorbate/menadione-induced oxidative stress in K562 human chronic myelogenous leukemic cells.

    Science.gov (United States)

    Verrax, Julien; Vanbever, Stéphanie; Stockis, Julie; Taper, Henryk; Calderon, Pedro Buc

    2007-03-15

    Among different features of cancer cells, two of them have retained our interest: their nearly universal glycolytic phenotype and their sensitivity towards an oxidative stress. Therefore, we took advantage of these features to develop an experimental approach by selectively exposing cancer cells to an oxidant insult induced by the combination of menadione (vitamin K(3)) and ascorbate (vitamin C). Ascorbate enhances the menadione redox cycling, increases the formation of reactive oxygen species and kills K562 cells as shown by more than 65% of LDH leakage after 24 hr of incubation. Since both lactate formation and ATP content are depressed by about 80% following ascorbate/menadione exposure, we suggest that the major intracellular event involved in such a cytotoxicity is related to the impairment of glycolysis. Indeed, NAD(+) is rapidly and severely depleted, a fact most probably related to a strong Poly(ADP-ribose) polymerase (PARP) activation, as shown by the high amount of poly-ADP-ribosylated proteins. The addition of N-acetylcysteine (NAC) restores most of the ATP content and the production of lactate as well. The PARP inhibitor dihydroxyisoquinoline (DiQ) was able to partially restore both parameters as well as cell death induced by ascorbate/menadione. These results suggest that the PARP activation induced by the oxidative stress is a major but not the only intracellular event involved in cell death by ascorbate/menadione. Due to the high energetic dependence of cancer cells on glycolysis, the impairment of such an essential pathway may explain the effectiveness of this combination to kill cancer cells. (c) 2006 Wiley-Liss, Inc.

  17. Vitamin K3 (menadione) redox cycling inhibits cytochrome P450-mediated metabolism and inhibits parathion intoxication

    Energy Technology Data Exchange (ETDEWEB)

    Jan, Yi-Hua [Department of Environmental and Occupational Medicine, Rutgers Robert Wood Johnson Medical School, Piscataway, NJ (United States); Richardson, Jason R., E-mail: jricha3@eohsi.rutgers.edu [Department of Environmental and Occupational Medicine, Rutgers Robert Wood Johnson Medical School, Piscataway, NJ (United States); Baker, Angela A. [Department of Environmental and Occupational Medicine, Rutgers Robert Wood Johnson Medical School, Piscataway, NJ (United States); Mishin, Vladimir [Department of Pharmacology and Toxicology, Rutgers University, Piscataway, NJ (United States); Heck, Diane E. [Department of Environmental Health Science, New York Medical College, Valhalla, NY (United States); Laskin, Debra L. [Department of Pharmacology and Toxicology, Rutgers University, Piscataway, NJ (United States); Laskin, Jeffrey D., E-mail: jlaskin@eohsi.rutgers.edu [Department of Environmental and Occupational Medicine, Rutgers Robert Wood Johnson Medical School, Piscataway, NJ (United States)

    2015-10-01

    Parathion, a widely used organophosphate insecticide, is considered a high priority chemical threat. Parathion toxicity is dependent on its metabolism by the cytochrome P450 system to paraoxon (diethyl 4-nitrophenyl phosphate), a cytotoxic metabolite. As an effective inhibitor of cholinesterases, paraoxon causes the accumulation of acetylcholine in synapses and overstimulation of nicotinic and muscarinic cholinergic receptors, leading to characteristic signs of organophosphate poisoning. Inhibition of parathion metabolism to paraoxon represents a potential approach to counter parathion toxicity. Herein, we demonstrate that menadione (methyl-1,4-naphthoquinone, vitamin K3) is a potent inhibitor of cytochrome P450-mediated metabolism of parathion. Menadione is active in redox cycling, a reaction mediated by NADPH-cytochrome P450 reductase that preferentially uses electrons from NADPH at the expense of their supply to the P450s. Using human recombinant CYP 1A2, 2B6, 3A4 and human liver microsomes, menadione was found to inhibit the formation of paraoxon from parathion. Administration of menadione bisulfite (40 mg/kg, ip) to rats also reduced parathion-induced inhibition of brain cholinesterase activity, as well as parathion-induced tremors and the progression of other signs and symptoms of parathion poisoning. These data suggest that redox cycling compounds, such as menadione, have the potential to effectively mitigate the toxicity of organophosphorus pesticides including parathion which require cytochrome P450-mediated activation. - Highlights: • Menadione redox cycles with cytochrome P450 reductase and generates reactive oxygen species. • Redox cycling inhibits cytochrome P450-mediated parathion metabolism. • Short term administration of menadione inhibits parathion toxicity by inhibiting paraoxon formation.

  18. Pankiller effect of prolonged exposure to menadione on glioma cells: potentiation by vitamin C.

    Science.gov (United States)

    Vita, Marina F; Nagachar, Nivedita; Avramidis, Dimitrios; Delwar, Zahid M; Cruz, Mabel H; Siden, Åke; Paulsson, Kajsa M; Yakisich, Juan Sebastian

    2011-12-01

    Menadione (Vitamin K3) has anti-tumoral effects against a wide range of cancer cells. Its potential toxicity to normal cells and narrow therapeutic range limit its use as single agent but in combination with radiation or other anti-neoplastic agents can be of therapeutic use. In this paper, we first evaluated the early (within 3 h) effect of menadione on ongoing DNA replication. In normal rat cerebral cortex mini-units menadione showed an age dependent anti-proliferative effect. In tissue mini-units prepared from newborn rats, menadione inhibited ongoing DNA replication with an IC (50) of approximately 10 μM but 50 μM had no effect on mini-units from prepared adult rat tissue. The effect of short (72 h) and prolonged exposure (1-2 weeks) to menadione alone in the DBTRG.05MG human glioma cells line and in combination with vitamin C was studied. After short period of exposure data show that menadione alone or in combination with vitamin C provided similar concentration-response curves (and IC(50) values). Prolonged exposure to these drugs was evaluated by their ability to kill 100% of glioma cells and prevent regrowth when cells are re-incubated in drug-free media. In this long-term assay, menadione:vitamin C at a ratio 1:100 showed higher anti-proliferative activity when compared to each drug alone and allowed to reduce each drug concentration between 2.5 to 5-fold. Similar anti-proliferative effect was demonstrated in 8 patient derived glioblastoma cell cultures. Our data should be able to encourage further advanced studies on animal models to evaluate the potential use of this combination therapy for glioma treatment.

  19. Vitamin K3 (menadione) redox cycling inhibits cytochrome P450-mediated metabolism and inhibits parathion intoxication

    International Nuclear Information System (INIS)

    Jan, Yi-Hua; Richardson, Jason R.; Baker, Angela A.; Mishin, Vladimir; Heck, Diane E.; Laskin, Debra L.; Laskin, Jeffrey D.

    2015-01-01

    Parathion, a widely used organophosphate insecticide, is considered a high priority chemical threat. Parathion toxicity is dependent on its metabolism by the cytochrome P450 system to paraoxon (diethyl 4-nitrophenyl phosphate), a cytotoxic metabolite. As an effective inhibitor of cholinesterases, paraoxon causes the accumulation of acetylcholine in synapses and overstimulation of nicotinic and muscarinic cholinergic receptors, leading to characteristic signs of organophosphate poisoning. Inhibition of parathion metabolism to paraoxon represents a potential approach to counter parathion toxicity. Herein, we demonstrate that menadione (methyl-1,4-naphthoquinone, vitamin K3) is a potent inhibitor of cytochrome P450-mediated metabolism of parathion. Menadione is active in redox cycling, a reaction mediated by NADPH-cytochrome P450 reductase that preferentially uses electrons from NADPH at the expense of their supply to the P450s. Using human recombinant CYP 1A2, 2B6, 3A4 and human liver microsomes, menadione was found to inhibit the formation of paraoxon from parathion. Administration of menadione bisulfite (40 mg/kg, ip) to rats also reduced parathion-induced inhibition of brain cholinesterase activity, as well as parathion-induced tremors and the progression of other signs and symptoms of parathion poisoning. These data suggest that redox cycling compounds, such as menadione, have the potential to effectively mitigate the toxicity of organophosphorus pesticides including parathion which require cytochrome P450-mediated activation. - Highlights: • Menadione redox cycles with cytochrome P450 reductase and generates reactive oxygen species. • Redox cycling inhibits cytochrome P450-mediated parathion metabolism. • Short term administration of menadione inhibits parathion toxicity by inhibiting paraoxon formation.

  20. Multidrug-resistance-associated protein plays a protective role in menadione-induced oxidative stress in endothelial cells.

    Science.gov (United States)

    Takahashi, Kyohei; Shibata, Tomohito; Oba, Tatsuya; Ishikawa, Tetsuya; Yoshikawa, Masahito; Tatsunami, Ryosuke; Takahashi, Kazuhiko; Tampo, Yoshiko

    2009-02-13

    Menadione, a redox-cycling quinone known to cause oxidative stress, binds to reduced glutathione (GSH) to form glutathione S-conjugate. Glutathione S-conjugates efflux is often mediated by multidrug-resistance-associated protein (MRP). We investigated the effect of a transporter inhibitor, MK571 (3-[[3-[2-(7-chloroquinolin-2-yl)vinyl]phenyl]-(2-dimethylcarbamoylethylsulfanyl)methylsulfanyl] propionic acid), on menadione-induced oxidative stress in bovine aortic endothelial cells (BAECs). BAECs were treated with menadione and MK571, and cell viability was measured. Modulation of intracellular GSH levels was performed with buthionine sulfoximine and GSH ethyl ester treatments. Intracellular superoxide was estimated by dihydroethidium oxidation using fluorescence microscopy or flow cytometry. Expression of MRP was determined by flow cytometry using phycoerythrin-conjugated anti-MRP monoclonal antibody. Intracellular GSH depletion by buthionine sulfoximine promoted the loss of viability of BAECs exposed to menadione. Exogenous GSH, which does not permeate the cell membrane, or GSH ethyl ester protected BAECs against the loss of viability induced by menadione. The results suggest that GSH binds to menadione outside the cells as well as inside. Pretreatment of BAECs with MK571 dramatically increased intracellular levels of superoxide generated from menadione, indicating that menadione may accumulate in the intracellular milieu. Finally, we found that MK571 aggravated menadione-induced toxicity in BAECs and that MRP levels were increased in menadione-treated cells. We conclude that MRP plays a vital role in protecting BAECs against menadione-induced oxidative stress, presumably due to its ability to transport glutathione S-conjugate.

  1. Transcriptomic profiling-based mutant screen reveals three new transcription factors mediating menadione resistance in Neurospora crassa.

    Science.gov (United States)

    Zhu, Jufen; Yu, Xinxu; Xie, Baogui; Gu, Xiaokui; Zhang, Zhenying; Li, Shaojie

    2013-06-01

    To gain insight into the regulatory mechanisms of oxidative stress responses in filamentous fungi, the genome-wide transcriptional response of Neurospora crassa to menadione was analysed by digital gene expression (DGE) profiling, which identified 779 upregulated genes and 576 downregulated genes. Knockout mutants affecting 130 highly-upregulated genes were tested for menadione sensitivity, which revealed that loss of the transcription factor siderophore regulation (SRE) (a transcriptional repressor for siderophore biosynthesis), catatase-3, cytochrome c peroxidase or superoxide dismutase 1 copper chaperone causes hypersensitivity to menadione. Deletion of sre dramatically increased transcription of the siderophore biosynthesis gene ono and the siderophore iron transporter gene sit during menadione stress, suggesting that SRE is required for repression of iron uptake under oxidative stress conditions. Contrary to its phenotype, the sre deletion mutant showed higher transcriptional levels of genes encoding reactive oxygen species (ROS) scavengers than wild type during menadione stress, which implies that the mutant suffers a higher level of oxidative stress than wild type. Uncontrolled iron uptake in the sre mutant might exacerbate cellular oxidative stress. This is the first report of a negative regulator of iron assimilation participating in the fungal oxidative stress response. In addition to SRE, eight other transcription factor genes were also menadione-responsive but their single gene knockout mutants showed wild-type menadione sensitivity. Two of them, named as mit-2 (menadione induced transcription factor-2) and mit-4 (menadione induced transcription factor-4), were selected for double mutant analysis. The double mutant was hypersensitive to menadione. Similarly, the double mutation of mit-2 and sre also had additive effects on menadione sensitivity, suggesting multiple transcription factors mediate oxidative stress resistance in an additive manner

  2. Effects of quercetin and menadione on intestinal calcium absorption and the underlying mechanisms.

    Science.gov (United States)

    Marchionatti, Ana M; Pacciaroni, Adriana; Tolosa de Talamoni, Nori G

    2013-01-01

    Quercetin (QT) could be considered as a potential therapeutic agent for different diseases due to its antioxidant, anti-inflammatory, antiviral and anticancer properties. This study was designed to investigate the ability of QT to protect the chick intestine against menadione (MEN) induced injury in vivo and in vitro. Four-week old chicks (Gallus gallus) were treated i.p. with 2.5μmol of MEN/kg b.w. or with i.l. 50μM QT or both. QT protected the intestinal Ca(2+) absorption against the inhibition caused by MEN, but QT alone did not modify. Glutathione (GSH) depletion provoked by MEN in chick enterocytes was abolished by QT treatment, whereas QT alone did not modify the intestinal GSH content. The enhancement of GSH peroxidase activity produced by MEN was blocked by QT treatment. In contrast, superoxide dismutase activity remained high after simultaneous treatment of enterocytes with MEN and QT. The flavonol also avoided changes in the mitochondrial membrane permeability (swelling) produced by MEN. The FasL/Fas/caspase-3 pathway was activated by MEN, effect that was abrogated by QT. In conclusion, QT may be useful in preventing inhibition of chick intestinal Ca(2+) absorption caused by MEN or other substances that deplete GSH, by blocking the oxidative stress and the FasL/Fas/caspase-3 pathway activation. Copyright © 2012 Elsevier Inc. All rights reserved.

  3. Effect of fast electrons and menadione on the structural and functional status of Ehrlich ascites tumor cells at early periods following irradiation

    International Nuclear Information System (INIS)

    Sejlanov, A.S.

    1989-01-01

    Irradiation of Ehrlich ascites tumor cells stimulates oxygen consumption, and menadione supresses cell respiration. The combined effect of the two factors produces an additional, in comparison with the effect of menadione alone, inhibition of the rate of oxygen consumption by cells. There is an additive effect of radiation and menadione with regard to the level of cell thiols and interphase cell death

  4. Vitamin K3 (menadione) redox cycling inhibits cytochrome P450-mediated metabolism and inhibits parathion intoxication.

    Science.gov (United States)

    Jan, Yi-Hua; Richardson, Jason R; Baker, Angela A; Mishin, Vladimir; Heck, Diane E; Laskin, Debra L; Laskin, Jeffrey D

    2015-10-01

    Parathion, a widely used organophosphate insecticide, is considered a high priority chemical threat. Parathion toxicity is dependent on its metabolism by the cytochrome P450 system to paraoxon (diethyl 4-nitrophenyl phosphate), a cytotoxic metabolite. As an effective inhibitor of cholinesterases, paraoxon causes the accumulation of acetylcholine in synapses and overstimulation of nicotinic and muscarinic cholinergic receptors, leading to characteristic signs of organophosphate poisoning. Inhibition of parathion metabolism to paraoxon represents a potential approach to counter parathion toxicity. Herein, we demonstrate that menadione (methyl-1,4-naphthoquinone, vitamin K3) is a potent inhibitor of cytochrome P450-mediated metabolism of parathion. Menadione is active in redox cycling, a reaction mediated by NADPH-cytochrome P450 reductase that preferentially uses electrons from NADPH at the expense of their supply to the P450s. Using human recombinant CYP 1A2, 2B6, 3A4 and human liver microsomes, menadione was found to inhibit the formation of paraoxon from parathion. Administration of menadione bisulfite (40mg/kg, ip) to rats also reduced parathion-induced inhibition of brain cholinesterase activity, as well as parathion-induced tremors and the progression of other signs and symptoms of parathion poisoning. These data suggest that redox cycling compounds, such as menadione, have the potential to effectively mitigate the toxicity of organophosphorus pesticides including parathion which require cytochrome P450-mediated activation. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. UDP-glucuronosyltransferases 1A6 and 1A10 catalyze reduced menadione glucuronidation

    International Nuclear Information System (INIS)

    Nishiyama, Takahito; Ohnuma, Tomokazu; Inoue, Yuu; Kishi, Takehiko; Ogura, Kenichiro; Hiratsuka, Akira

    2008-01-01

    Menadione (2-methyl-1,4-naphthoquine), also known as vitamin K3, has been widely used as a model compound in the field of oxidative stress-related research. The metabolism of menadione has been studied, and it is known that menadione undergoes a two-electron reduction by NAD(P)H:Quinone oxidoreductase 1 (NQO1) after which the reduced form of menadione (2-methyl-1,4-naphthalenediol, menadiol) is glucuronidated and excreted in urine. To investigate which human UDP-glucuronosyltransferase (UGT) isoforms participate in the glucuronidation of menadiol reduced by NQO1 from menadione, we first constructed heterologously expressed NQO1 in Sf9 cells and tested the menadiol glucuronidating activity of 16 human recombinant UGT isoforms. Of the 16 UGT isoforms, UGTs 1A6, 1A7, 1A8, 1A9, and 1A10 catalyzed menadiol glucuronidation, and, of these, UGTs 1A6 and 1A10 catalyzed menadiol glucuronidation at much higher rates than the other UGTs. Menadiol was regioselectively glucuronidated in the manner of 4-position > 1-position by UGTs 1A7, 1A8, 1A9, and 1A10. In contrast to these UGTs, only UGT1A6 exhibited 1-menadiol-preferential glucuronidating activity. The results suggest possible detoxification pathways for quinones via NQO1 reduction followed by UGT glucuronidation

  6. Biotransformation of menadione to its prenylated derivative MK-3 using recombinant Pichia pastoris.

    Science.gov (United States)

    Li, Zhemin; Zhao, Genhai; Liu, Hui; Guo, Yugang; Wu, Hefang; Sun, Xiaowen; Wu, Xihua; Zheng, Zhiming

    2017-07-01

    Prenylated quinones, especially menaquinones, have significant physiological activities, but are arduous to synthesize efficiently. Due to the relaxed aromatic substrate specificity and prenylation regiospecificity at the ortho- site of the phenolic hydroxyl group, the aromatic prenyltransferase NovQ from Streptomyces may be useful in menaquinone synthesis from menadione. In this study, NovQ was overexpressed in Pichia pastoris. After fermentation optimization, NovQ production increased by 1617%. Then the different effects of metal ions, detergents and pH on the activity of purified NovQ were investigated to optimize the prenylation reaction. Finally, purified NovQ and cells containing NovQ were used for menadione prenylation in vitro and in vivo, respectively. Menaquinone-1 (MK-1) was detected as the only product in vitro with γ,γ-dimethylallyl pyrophosphate and menadione hydroquinol substrates. MK-3 at a concentration of 90.53 mg/L was detected as the major product of whole cell catalysis with 3-methyl-2-buten-1-ol and menadione hydroquinol substrates. This study realized whole cell catalysis converting menadione to menaquinones.

  7. In vitro Activation of heme oxygenase-2 by menadione and its analogs.

    Science.gov (United States)

    Vukomanovic, Dragic; Rahman, Mona N; Bilokin, Yaroslav; Golub, Andriy G; Brien, James F; Szarek, Walter A; Jia, Zongchao; Nakatsu, Kanji

    2014-02-18

    Previously, we reported that menadione activated rat, native heme oxygenase-2 (HO-2) and human recombinant heme oxygenase-2 selectively; it did not activate spleen, microsomal heme oxygenase-1. The purpose of this study was to explore some structure-activity relationships of this activation and the idea that redox properties may be an important aspect of menadione efficacy. Heme oxygenase activity was determined in vitro using rat spleen and brain microsomes as the sources of heme oxygenase-1 and -2, respectively, as well as recombinant, human heme oxygenase-2. Menadione analogs with bulky aliphatic groups at position-3, namely vitamins K1 and K2, were not able to activate HO-2. In contrast, several compounds with similar bulky but less lipophilic moieties at position-2 (and -3) were able to activate HO-2 many fold; these compounds included polar, rigid, furan-containing naphthoquinones, furan-benzoxazine naphthoquinones, 2-(aminophenylphenyl)-3-piperidin-1-yl naphthoquinones. To explore the idea that redox properties might be involved in menadione efficacy, we tested analogs such as 1,4-dimethoxy-2-methylnaphthalene, pentafluoromenadione, monohalogenated naphthoquinones, α-tetralone and 1,4-naphthoquinone. All of these compounds were inactive except for 1,4-naphthoquinone. Menadione activated full-length recombinant human heme oxygenase-2 (FL-hHO-2) as effectively as rat brain enzyme, but it did not activate rat spleen heme oxygenase. These observations are consistent with the idea that naphthoquinones such as menadione bind to a receptor in HO-2 and activate the enzyme through a mechanism that may involve redox properties.

  8. Flow-injection fluorimetric determination of menadione using on-line photo-reduction in micellar media

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Ruiz, Tomas; Martinez-Lozano, Carmen; Tomas, Virginia; Martin, Jesus

    2004-07-01

    A very sensitive fluorimetric method for the determination of menadione using a flow injection system is proposed. The method is based on the on-line reduction of menadione in dodecylsulphate micelles upon irradiation with UV light. The strong fluorescence of the reduced menadione in micellar medium is measured at 410 nm with excitation at 340 nm. The method shows a linear range between 2.42 and 245 ng ml{sup -1} and a limit of detection of 0.18 ng ml{sup -1}. The sample throughput was 90 injections per hour. The applicability of the assay was demonstrated by analysing this vitamin in commercial pharmaceutical preparations.

  9. Flow-injection fluorimetric determination of menadione using on-line photo-reduction in micellar media

    International Nuclear Information System (INIS)

    Perez-Ruiz, Tomas; Martinez-Lozano, Carmen; Tomas, Virginia; Martin, Jesus

    2004-01-01

    A very sensitive fluorimetric method for the determination of menadione using a flow injection system is proposed. The method is based on the on-line reduction of menadione in dodecylsulphate micelles upon irradiation with UV light. The strong fluorescence of the reduced menadione in micellar medium is measured at 410 nm with excitation at 340 nm. The method shows a linear range between 2.42 and 245 ng ml -1 and a limit of detection of 0.18 ng ml -1 . The sample throughput was 90 injections per hour. The applicability of the assay was demonstrated by analysing this vitamin in commercial pharmaceutical preparations

  10. Antioxidant and antiapoptotic properties of melatonin restore intestinal calcium absorption altered by menadione.

    Science.gov (United States)

    Carpentieri, A; Marchionatti, A; Areco, V; Perez, A; Centeno, V; Tolosa de Talamoni, N

    2014-02-01

    The intestinal Ca²⁺ absorption is inhibited by menadione (MEN) through oxidative stress and apoptosis. The aim of this study was to elucidate whether the antioxidant and antiapoptotic properties of melatonin (MEL) could protect the gut against the oxidant MEN. For this purpose, 4-week-old chicks were divided into four groups: (1) controls, (2) treated i.p. with MEN (2.5 μmol/kg of b.w.), (3) treated i.p. with MEL (10 mg/kg of b.w.), and (4) treated with 10 mg MEL/kg of b.w after 2.5 μmol MEN/kg of b.w. Oxidative stress was assessed by determination of glutathione (GSH) and protein carbonyl contents as well as antioxidant enzyme activities. Apoptosis was assayed by the TUNEL technique, protein expression, and activity of caspase 3. The data show that MEL restores the intestinal Ca²⁺ absorption altered by MEN. In addition, MEL reversed the effects caused by MEN such as decrease in GSH levels, increase in the carbonyl content, alteration in mitochondrial membrane permeability, and enhancement of superoxide dismutase and catalase activities. Apoptosis triggered by MEN in the intestinal cells was arrested by MEL, as indicated by normalization of the mitochondrial membrane permeability, caspase 3 activity, and DNA fragmentation. In conclusion, MEL reverses the inhibition of intestinal Ca²⁺ absorption produced by MEN counteracting oxidative stress and apoptosis. These findings suggest that MEL could be a potential drug of choice for the reversal of impaired intestinal Ca²⁺ absorption in certain gut disorders that occur with oxidative stress and apoptosis.

  11. Cytotoxic effect of menadione and sodium orthovanadate in combination on human glioma cells.

    Science.gov (United States)

    Delwar, Zahid M; Avramidis, Dimitrios; Follin, Elna; Hua, Yan; Siden, Åke; Cruz, Mabel; Paulsson, Kajsa M; Yakisich, Juan Sebastian

    2012-08-01

    Gliomas are the most common primary brain tumor, and their treatment is still a challenge. Here, we evaluated the antiproliferative effect of a novel combination of two potent oxidative stress enhancers: menadione (M) and sodium orthovanadate (SO). We observed both short-term and prolonged growth inhibitory effects of M or SO alone as well as in combination (M:SO) on DBTRG.05MG human glioma cells. A stronger antiproliferative effect was observed in the short-term proliferation assay with the M:SO combination compared to either investigated agent alone. In the long-term proliferation assay, a 10-day exposure to M:SO at concentrations of 10 μM:17.5 μM or 17.5 μM:10 μM was enough to kill 100% of the cells; no cell regrowth was observed after re-incubation in drug-free media. When used in combination, the single concentration of M and SO could be decreased by 2.5- to 5-fold of those used for each experimental drug alone and still obtain a similar antiproliferative effect. The underlying molecular mechanism was investigated by co-incubating M:SO with dithiothreitol (DTT) and genistein. Both substances partially neutralized the effects of the M:SO combination, showing additive effects. This observation suggests a role of oxidative stress and tyrosine kinase stimulation in the M:SO cytotoxic effect. Our results indicate that M:SO combination is an attractive alternative for glioma treatment that encourages further study. The neutralizing effects of genistein and DTT reveal a possibility for their use in the minimization of potential M:SO systemic toxicity.

  12. Adaptive stress response to menadione-induced oxidative stress in Saccharomyces cerevisiae KNU5377.

    Science.gov (United States)

    Kim, Il-Sup; Sohn, Ho-Yong; Jin, Ingnyol

    2011-10-01

    The molecular mechanisms involved in the ability of yeast cells to adapt and respond to oxidative stress are of great interest to the pharmaceutical, medical, food, and fermentation industries. In this study, we investigated the time-dependent, cellular redox homeostasis ability to adapt to menadione-induced oxidative stress, using biochemical and proteomic approaches in Saccharomyces cerevisiae KNU5377. Time-dependent cell viability was inversely proportional to endogenous amounts of ROS measured by a fluorescence assay with 2',7'-dichlorofluorescin diacetate (DCFHDA), and was hypersensitive when cells were exposed to the compound for 60 min. Morphological changes, protein oxidation and lipid peroxidation were also observed. To overcome the unfavorable conditions due to the presence of menadione, yeast cells activated a variety of cell rescue proteins including antioxidant enzymes, molecular chaperones, energy-generating metabolic enzymes, and antioxidant molecules such as trehalose. Thus, these results show that menadione causes ROS generation and high accumulation of cellular ROS levels, which affects cell viability and cell morphology and there is a correlation between resistance to menadione and the high induction of cell rescue proteins after cells enter into this physiological state, which provides a clue about the complex and dynamic stress response in yeast cells.

  13. Oxidative stress response to menadione and cumene hydroperoxide in the opportunistic fungal pathogen Candida glabrata

    Directory of Open Access Journals (Sweden)

    Mayra Cuéllar-Cruz

    2009-07-01

    Full Text Available Candida glabrata is an opportunistic fungal pathogen that can cause severe invasive infections and can evade phagocytic cell clearance. We are interested in understanding the virulence of this fungal pathogen, in particular its oxidative stress response. Here we investigated C. glabrata, Saccharomyces cerevisiae and Candida albicans responses to two different oxidants: menadione and cumene hydroperoxide (CHP. In log-phase, in the presence of menadione, C. glabrata requires Cta1p (catalase, while in a stationary phase (SP, Cta1p is dispensable. In addition, C. glabrata is less resistant to menadione than C. albicans in SP. The S. cerevisiae laboratory reference strain is less resistant to menadione than C. glabrata and C. albicans; however S. cerevisiaeclinical isolates (CIs are more resistant than the lab reference strain. Furthermore, S. cerevisiae CIs showed an increased catalase activity. Interestingly, in SP C. glabrata and S. cerevisiae are more resistant to CHP than C. albicans and Cta1p plays no apparent role in detoxifying this oxidant.

  14. Exposure of the blue mussel, Mytilus edulis, to gold nanoparticles and the pro-oxidant menadione.

    Science.gov (United States)

    Tedesco, Sara; Doyle, Hugh; Blasco, Julian; Redmond, Gareth; Sheehan, David

    2010-03-01

    Relatively little is known about how gold nanoparticles (GNP) might interact in vivo with marine organisms. Mytilus edulis was exposed (24h) to approximately 15 nm GNP, menadione and both compounds simultaneously (GNP/menadione). GNP was detected by inductively coupled plasma-optical emission spectroscopy mainly in digestive gland of samples exposed to GNP though not GNP/menadione, perhaps due to impaired feeding. Thioredoxin reductase activity and malondialdehyde levels were determined in all tissues. Thioredoxin reductase inhibition was detected only in digestive gland exposed to menadione whilst malondialdehyde levels did not vary in response to treatment in all tissues. GNP caused a decrease in the reduced/oxidized glutathione ratio in digestive gland, but no difference was found in other tissues or for other treatments. One dimensional electrophoresis of proteins containing thiol groups was performed in all tissues and revealed a reduction in protein thiols for all treatments in digestive gland. Two dimensional electrophoresis of digestive gland extracts, from GNP and control groups, showed decreased levels of thiol proteins in response to GNP which we attribute to oxidation. Our results suggest that GNP causes a modest level of oxidative stress sufficient to oxidize thiols in glutathione and proteins but without causing lipid peroxidation or induction of thioredoxin reductase activity.

  15. Menadione partially restores NADH-oxidation and ATP-synthesis in complex I deficient fibroblasts

    NARCIS (Netherlands)

    Wijburg, F. A.; Feller, N.; de Groot, C. J.; Wanders, R. J.

    1990-01-01

    In this paper we report our studies on the effects of menadione in cultured fibroblasts treated with rotenone to block complex I. A normalization of the lactate to pyruvate ratio after incubation with glucose, an increased production of 14CO2 from [6-14C]glucose and an increased intra-cellular

  16. Menadione degrades the optical quality and mitochondrial integrity of bovine crystalline lenses.

    Science.gov (United States)

    Olsen, Kenneth W; Bantseev, Vladimir; Choh, Vivan

    2011-01-26

    The crystalline lens is a unique cellular organ that performs metabolic processes while maintaining transparency for optical functionality. Mitochondria play a role in providing cells with aerobic respiration necessary for these metabolic processes. Using menadione, a mitochondria-specific inhibitor of the quinone family, and bovine lenses in vitro, this study was undertaken to determine whether a relationship exists between mitochondrial function and optical function. Bovine lenses were treated with 50 μM, 200 μM, 600 μM, and 1,000 μM menadione and lens optical function, assessed as optical quality, was observed over 9 days. Confocal micrographs of mitochondria in superficial secondary fiber cells were also analyzed in 50 μM, 200 μM, and 600 μM menadione-treated lenses over 48 h. A decrease in lens optical quality was observed in a dose-dependent manner within 24 h for the 200 µM- (p=0.0422), 600 µM- (pmenadione. The data show that menadione has a detrimental effect on mitochondrial integrity and this change is associated with degradation of optical quality, suggesting a possible link between mitochondrial function and optical function.

  17. A biophysical approach to menadione membrane interactions: relevance for menadione-induced mitochondria dysfunction and related deleterious/therapeutic effects.

    Science.gov (United States)

    Monteiro, João P; Martins, André F; Nunes, Cláudia; Morais, Catarina M; Lúcio, Marlene; Reis, Salette; Pinheiro, Teresa J T; Geraldes, Carlos F G C; Oliveira, Paulo J; Jurado, Amália S

    2013-08-01

    Menadione (MEN), a polycyclic aromatic ketone, was shown to promote cell injury by imposing massive oxidative stress and has been proposed as a promising chemotherapeutic agent for the treatment of cancer diseases. The mechanisms underlying MEN-induced mitochondrial dysfunction and cell death are not yet fully understood. In this work, a systematic study was performed to unveil the effects of MEN on membrane lipid organization, using models mimicking mitochondrial membranes and native mitochondrial membranes. MEN was found to readily incorporate in membrane systems composed of a single phospholipid (phosphatidylcholine) or the lipids dioleoylphosphatidylcholine, dioleoylphosphatidylethanolamine and tetraoleoylcardiolipin at 1:1:1 molar ratio, as well as in mitochondrial membranes. Increased permeability in both membrane models, monitored by calcein release, seemed to correlate with the extent of MEN incorporation into membranes. MEN perturbed the physical properties of vesicles composed of dipalmitoylphosphatidylcholine or dipalmitoylphosphatidylethanolamine plus tetraoleoylcardiolipin (at 7:3 molar ratio), as reflected by the downshift of the lipid phase transition temperature and the emergence of a new transition peak in the mixed lipid system, detected by DSC. (31)P NMR studies revealed that MEN favored the formation of non-lamellar structures. Also, quenching studies with the fluorescent probes DPH and TMA-DPH showed that MEN distributed across the bilayer thickness in both model and native mitochondrial membranes. MEN's ability to promote alterations of membrane lipid organization was related with its reported mitochondrial toxicity and promotion of apoptosis, predictably involved in its anti-carcinogenic activity. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. Oxyradical Stress, Endocannabinoids, and Atherosclerosis

    Directory of Open Access Journals (Sweden)

    Anberitha T. Matthews

    2015-12-01

    Full Text Available Atherosclerosis is responsible for most cardiovascular disease (CVD and is caused by several factors including hypertension, hypercholesterolemia, and chronic inflammation. Oxidants and electrophiles have roles in the pathophysiology of atherosclerosis and the concentrations of these reactive molecules are an important factor in disease initiation and progression. Overactive NADPH oxidase (Nox produces excess superoxide resulting in oxidized macromolecules, which is an important factor in atherogenesis. Although superoxide and reactive oxygen species (ROS have obvious toxic properties, they also have fundamental roles in signaling pathways that enable cells to adapt to stress. In addition to inflammation and ROS, the endocannabinoid system (eCB is also important in atherogenesis. Linkages have been postulated between the eCB system, Nox, oxidative stress, and atherosclerosis. For instance, CB2 receptor-evoked signaling has been shown to upregulate anti-inflammatory and anti-oxidative pathways, whereas CB1 signaling appears to induce opposite effects. The second messenger lipid molecule diacylglycerol is implicated in the regulation of Nox activity and diacylglycerol lipase β (DAGLβ is a key biosynthetic enzyme in the biosynthesis eCB ligand 2-arachidonylglycerol (2-AG. Furthermore, Nrf2 is a vital transcription factor that protects against the cytotoxic effects of both oxidant and electrophile stress. This review will highlight the role of reactive oxygen species (ROS in intracellular signaling and the impact of deregulated ROS-mediated signaling in atherogenesis. In addition, there is also emerging knowledge that the eCB system has an important role in atherogenesis. We will attempt to integrate oxidative stress and the eCB system into a conceptual framework that provides insights into this pathology.

  19. Role of a novel dual flavin reductase (NR1) and an associated histidine triad protein (DCS-1) in menadione-induced cytotoxicity

    International Nuclear Information System (INIS)

    Kwasnicka-Crawford, Dorota A.; Vincent, Steven R.

    2005-01-01

    Microsomal cytochrome P450 reductase catalyzes the one-electron transfer from NADPH via FAD and FMN to various electron acceptors, such as cytochrome P450s or to some anti-cancer quinone drugs. This results in generation of free radicals and toxic oxygen metabolites, which can contribute to the cytotoxicity of these compounds. Recently, a cytosolic NADPH-dependent flavin reductase, NR1, has been described which is highly homologous to the microsomal cytochrome P450 reductase. In this study, we show that over-expression of NR1 in human embryonic kidney cells enhances the cytotoxic action of the model quinone, menadione. Furthermore, we show that a novel human histidine triad protein DCS-1, which is expressed together with NR1 in many tissues, can significantly reduce menadione-induced cytotoxicity in these cells. We also show that DCS-1 binds NF1 and directly modulates its activity. These results suggest that NR1 may play a role in carcinogenicity and cell death associated with one-electron reductions

  20. Cellular determinants involving mitochondrial dysfunction, oxidative stress and apoptosis correlate with the synergic cytotoxicity of epigallocatechin-3-gallate and menadione in human leukemia Jurkat T cells.

    Science.gov (United States)

    Tofolean, Ioana Teodora; Ganea, Constanta; Ionescu, Diana; Filippi, Alexandru; Garaiman, Alexandru; Goicea, Alexandru; Gaman, Mihnea-Alexandru; Dimancea, Alexandru; Baran, Irina

    2016-01-01

    We have investigated the growth-suppressive action of epigallocatechin-3-gallate (EGCG) on human leukemia Jurkat T cells. Results show a strong correlation between the dose-dependent reduction of clonogenic survival following acute EGCG treatments and the EGCG-induced decline of the mitochondrial level of Ca(2+). The cell killing ability of EGCG was synergistically enhanced by menadione. In addition, the cytotoxic effect of EGCG applied alone or in combination with menadione was accompanied by apoptosis induction. We also observed that in acute treatments EGCG displays strong antioxidant properties in the intracellular milieu, but concurrently triggers some oxidative stress generating mechanisms that can fully develop on a longer timescale. In parallel, EGCG dose-dependently induced mitochondrial depolarization during exposure, but this condition was subsequently reversed to a persistent hyperpolarized mitochondrial state that was dependent on the activity of respiratory Complex I. Fluorimetric measurements suggest that EGCG is a mitochondrial Complex III inhibitor and indicate that EGCG evokes a specific cellular fluorescence with emission at 400nm and two main excitation bands (at 330nm and 350nm) that may originate from a mitochondrial supercomplex containing dimeric Complex III and dimeric ATP-synthase, and therefore could provide a valuable means to characterize the functional properties of the respiratory chain. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Cooperation of NAD(P)H:quinone oxidoreductase 1 and UDP-glucuronosyltransferases reduces menadione cytotoxicity in HEK293 cells.

    Science.gov (United States)

    Nishiyama, Takahito; Izawa, Tadashi; Usami, Mami; Ohnuma, Tomokazu; Ogura, Kenichiro; Hiratsuka, Akira

    2010-04-09

    Previous studies have shown that NAD(P)H:quinone oxidoreductase 1 (NQO1) plays an important role in the detoxification of menadione (2-methyl-1,4-naphthoquinone, also known as vitamin K3). However, menadiol (2-methyl-1,4-naphthalenediol) formed from menadione by NQO1-mediated reduction continues to be an unstable substance, which undergoes the reformation of menadione with concomitant formation of reactive oxygen species (ROS). Hence, we focused on the roles of phase II enzymes, with particular attention to UDP-glucuronosyltransferases (UGTs), in the detoxification process of menadione. In this study, we established an HEK293 cell line stably expressing NQO1 (HEK293/NQO1) and HEK293/NQO1 cell lines with doxycycline (DOX)-regulated expression of UGT1A6 (HEK293/NQO1/UGT1A6) and UGT1A10 (HEK293/NQO1/UGT1A10), and evaluated the role of NQO1 and UGTs against menadione-induced cytotoxicity. Our results differed from those of previous studies. HEK293/NQO1 was the most sensitive cell line to menadione cytotoxicity among cell lines established in this study. These phenomena were also observed in HEK293/NQO1/UGT1A6 and HEK293/NQO1/UGT1A10 cells in which the expression of UGT was suppressed by DOX treatment. On the contrary, HEK293/NQO1/UGT1A6 and HEK293/NQO1/UGT1A10 cells without DOX treatment were resistant to menadione-induced cytotoxicity. These results demonstrated that NQO1 is not a detoxification enzyme for menadione and that UGT-mediated glucuronidation of menadiol is the most important detoxification process. Copyright 2009 Elsevier Inc. All rights reserved.

  2. Menadione induces the formation of reactive oxygen species and depletion of GSH-mediated apoptosis and inhibits the FAK-mediated cell invasion.

    Science.gov (United States)

    Kim, Yun Jeong; Shin, Yong Kyoo; Sohn, Dong Suep; Lee, Chung Soo

    2014-09-01

    Menadione induces apoptosis in tumor cells. However, the mechanism of apoptosis in ovarian cancer cells exposed to menadione is not clear. In addition, it is unclear whether menadione-induced apoptosis is mediated by the depletion of glutathione (GSH) contents that is associated with the formation of reactive oxygen species. Furthermore, the effect of menadione on the invasion and migration of human epithelial ovarian cancer cells has not been studied. Therefore, we investigated the effects of menadione exposure on apoptosis, cell adhesion, and cell migration using the human epithelial ovarian carcinoma cell lines OVCAR-3 and SK-OV-3. The results suggest that menadione may induce apoptotic cell death in ovarian carcinoma cell lines by activating the mitochondrial pathway and the caspase-8- and Bid-dependent pathways. The apoptotic effect of menadione appears to be mediated by the formation of reactive oxygen species and the depletion of GSH. Menadione inhibited fetal-bovine-serum-induced cell adhesion and migration of OVCAR-3 cells, possibly through the suppression the focal adhesion kinase (FAK)-dependent activation of cytoskeletal-associated components. Therefore, menadione might be beneficial in the treatment of epithelial ovarian adenocarcinoma and combination therapy.

  3. Effect of menadione and hydrogen peroxide on catalase activity in Saccharomyces yeast strains

    Directory of Open Access Journals (Sweden)

    Nadejda EFREMOVA

    2013-05-01

    Full Text Available It has been studied the possibility of utilization of two important oxidant factors as regulators of catalase activity in Saccharomyces yeasts. In this paper results of the screening of some Saccharomyces yeast strains for potential producers of catalase are presented. Results of the screening for potential catalase producer have revealed that Saccharomyces cerevisiae CNMN-Y-11 strain possesses the highest catalase activity (2900 U/mg protein compared with other samples. Maximum increase of catalase activity with 50-60% compared to the reference sample was established in the case of hydrogen peroxide and menadione utilization in optimal concentrations of 15 and 10 mM. This research has been demonstrated the potential benefits of application of hydrogen peroxide and menadione as stimulatory factors of catalase activity in Saccharomyces yeasts.

  4. Cytotoxicity mechanism of two naphthoquinones (menadione and plumbagin in Saccharomyces cerevisiae.

    Directory of Open Access Journals (Sweden)

    Frederico Augusto Vieira Castro

    Full Text Available BACKGROUND: Quinones are compounds extensively used in studies of oxidative stress due to their role in plants as chemicals for defense. These compounds are of great interest for pharmacologists and scientists, in general, because several cancer chemotherapeutic agents contain the quinone nucleus. However, due to differences in structures and diverse pharmacological effects, the exact toxicity mechanisms exerted by quinones are far from elucidatation. METHODOLOGY/PRINCIPAL FINDINGS: Using Saccharomyces cerevisiae, we evaluated the main mechanisms of toxicity of two naphthoquinones, menadione and plumbagin, by determining tolerance and oxidative stress biomarkers such as GSH and GSSG, lipid peroxidation levels, as well as aconitase activity. The importance of glutathione transferases (GST in quinone detoxification was also addressed. The GSSG/GSH ratio showed that menadione seemed to exert its toxicity mainly through the generation of ROS while plumbagin acted as an electrophile reacting with GSH. However, the results showed that, even by different pathways, both drugs were capable of generating oxidative stress through their toxic effects. Our results showed that the control strain, BY4741, and the glutathione transferase deficient strains (gtt1Delta and gtt2Delta were sensitive to both compounds. With respect to the role of GST isoforms in cellular protection against quinone toxicity, we observed that the Gtt2 deficient strain was unable to overcome lipid peroxidation, even after a plumbagin pre-treatment, indicating that this treatment did not improve tolerance when compared with the wild type strain. Cross-tolerance experiments confirmed distinct cytotoxicity mechanisms for these naphthoquinones since only a pre-treatment with menadione was able to induce acquisition of tolerance against stress with plumbagin. CONCLUSIONS/SIGNIFICANCE: These results suggest different responses to menadione and plumbagin which could be due to the fact that

  5. Cytotoxicity Mechanism of Two Naphthoquinones (Menadione and Plumbagin) in Saccharomyces cerevisiae

    Science.gov (United States)

    Castro, Frederico Augusto Vieira; Mariani, Diana; Panek, Anita Dolly; Eleutherio, Elis Cristina Araújo; Pereira, Marcos Dias

    2008-01-01

    Background Quinones are compounds extensively used in studies of oxidative stress due to their role in plants as chemicals for defense. These compounds are of great interest for pharmacologists and scientists, in general, because several cancer chemotherapeutic agents contain the quinone nucleus. However, due to differences in structures and diverse pharmacological effects, the exact toxicity mechanisms exerted by quinones are far from elucidatation. Methodology/Principal Findings Using Saccharomyces cerevisiae, we evaluated the main mechanisms of toxicity of two naphthoquinones, menadione and plumbagin, by determining tolerance and oxidative stress biomarkers such as GSH and GSSG, lipid peroxidation levels, as well as aconitase activity. The importance of glutathione transferases (GST) in quinone detoxification was also addressed. The GSSG/GSH ratio showed that menadione seemed to exert its toxicity mainly through the generation of ROS while plumbagin acted as an electrophile reacting with GSH. However, the results showed that, even by different pathways, both drugs were capable of generating oxidative stress through their toxic effects. Our results showed that the control strain, BY4741, and the glutathione transferase deficient strains (gtt1Δ and gtt2Δ) were sensitive to both compounds. With respect to the role of GST isoforms in cellular protection against quinone toxicity, we observed that the Gtt2 deficient strain was unable to overcome lipid peroxidation, even after a plumbagin pre-treatment, indicating that this treatment did not improve tolerance when compared with the wild type strain. Cross-tolerance experiments confirmed distinct cytotoxicity mechanisms for these naphthoquinones since only a pre-treatment with menadione was able to induce acquisition of tolerance against stress with plumbagin. Conclusions/Significance These results suggest different responses to menadione and plumbagin which could be due to the fact that these compounds use different

  6. Menadione induces G2/M arrest in gastric cancer cells by down-regulation of CDC25C and proteasome mediated degradation of CDK1 and cyclin B1

    OpenAIRE

    Lee, Min Ho; Cho, Yoonjung; Kim, Do Hyun; Woo, Hyun Jun; Yang, Ji Yeong; Kwon, Hye Jin; Yeon, Min Ji; Park, Min; Kim, Sa-Hyun; Moon, Cheol; Tharmalingam, Nagendran; Kim, Tae Ue; Kim, Jong-Bae

    2016-01-01

    Menadione (vitamin K3) has been reported to induce apoptotic cell death and growth inhibition in various types of cancer cells. However, involvement of menadione in cell cycle control has not been considered in gastric cancer cells yet. In the current study, we have investigated whether menadione is involved in the cell cycle regulation and suppression of growth in gastric cancer cells. In the cell cycle analysis, we found that menadione induced G2/M cell cycle arrest in AGS cells. To elucida...

  7. Novel approaches to mitigating parathion toxicity: targeting cytochrome P450–mediated metabolism with menadione

    Science.gov (United States)

    Jan, Yi-Hua; Richardson, Jason R.; Baker, Angela A.; Mishin, Vladimir; Heck, Diane E.; Laskin, Debra L.; Laskin, Jeffrey D.

    2016-01-01

    Accidental or intentional exposures to parathion, an organophosphorus (OP) pesticide, can cause severe poisoning in humans. Parathion toxicity is dependent on its metabolism by the cytochrome P450 (CYP) system to paraoxon (diethyl 4-nitrophenyl phosphate), a highly poisonous nerve agent and potent inhibitor of acetylcholinesterase (AChE). We have been investigating inhibitors of CYP-mediated bioactivation of OPs as a method of preventing or reversing progressive parathion toxicity. It is well recognized that NADPH–cytochrome P450 reductase, an enzyme required for the transfer of electrons to CYPs, mediates chemical redox cycling. In this process, the enzyme diverts electrons from CYPs to support chemical redox cycling, which results in inhibition of CYP-mediated biotransformation. Using menadione as the redox-cycling chemical, we discovered that this enzymatic reaction blocks metabolic activation of parathion in rat and human liver microsomes and in recombinant CYPs important to parathion metabolism, including CYP1A2, CYP2B6, and CYP3A4. Administration of menadione to rats reduces metabolism of parathion, as well as parathion-induced inhibition of brain cholinesterase activity. This resulted in inhibition of parathion neurotoxicity. Menadione has relatively low toxicity and is approved by the FDA for other indications. Its ability to block parathion metabolism makes it an attractive therapeutic candidate to mitigate parathion-induced neurotoxicity. PMID:27441453

  8. Novel approaches to mitigating parathion toxicity: targeting cytochrome P450-mediated metabolism with menadione.

    Science.gov (United States)

    Jan, Yi-Hua; Richardson, Jason R; Baker, Angela A; Mishin, Vladimir; Heck, Diane E; Laskin, Debra L; Laskin, Jeffrey D

    2016-08-01

    Accidental or intentional exposures to parathion, an organophosphorus (OP) pesticide, can cause severe poisoning in humans. Parathion toxicity is dependent on its metabolism by the cytochrome P450 (CYP) system to paraoxon (diethyl 4-nitrophenyl phosphate), a highly poisonous nerve agent and potent inhibitor of acetylcholinesterase. We have been investigating inhibitors of CYP-mediated bioactivation of OPs as a method of preventing or reversing progressive parathion toxicity. It is well recognized that NADPH-cytochrome P450 reductase, an enzyme required for the transfer of electrons to CYPs, mediates chemical redox cycling. In this process, the enzyme diverts electrons from CYPs to support chemical redox cycling, which results in inhibition of CYP-mediated biotransformation. Using menadione as the redox-cycling chemical, we discovered that this enzymatic reaction blocks metabolic activation of parathion in rat and human liver microsomes and in recombinant CYPs important to parathion metabolism, including CYP1A2, CYP2B6, and CYP3A4. Administration of menadione to rats reduces metabolism of parathion, as well as parathion-induced inhibition of brain cholinesterase activity. This resulted in inhibition of parathion neurotoxicity. Menadione has relatively low toxicity and is approved by the Food and Drug Administration for other indications. Its ability to block parathion metabolism makes it an attractive therapeutic candidate to mitigate parathion-induced neurotoxicity. © 2016 New York Academy of Sciences.

  9. Phosphoinositide 3-kinase/Akt signalling is responsible for the differential susceptibility of myoblasts and myotubes to menadione-induced oxidative stress.

    Science.gov (United States)

    Lim, Jeong A; Woo, Joo Hong; Kim, Hye Sun

    2008-09-01

    In this study, it was found that undifferentiated myoblasts were more vulnerable to menadione-induced oxidative stress than differentiated myotubes. Cell death occurred with a relatively low concentration of menadione in myoblasts compared to myotubes. With the same concentration of menadione, the Bcl-2/Bax ratio decreased and nuclei containing condensed chromatin were observed in myoblasts to a greater extent than in myotubes. However, myotubes became increasingly susceptible to menadione when phosphoinositide 3-kinase (PI3-K) was blocked by pre-incubation with LY294002, a PI3-K inhibitor. Actually, PI3-K activity was reduced by menadione in myoblasts but not in myotubes. In addition, the phosphorylation of Akt, a downstream effector of PI3-K, was inhibited in myoblasts by menadione but increased in myotubes. Both LY294002 and API-2, an Akt inhibitor, decreased the Bcl-2/Bax ratio in menadione-exposed myotubes. These results suggest that the differential activity of PI3-K/Akt signalling is responsible for the differential susceptibility of myoblasts and myotubes to menadione-induced oxidative stress.

  10. Sex-related effects of imidacloprid modulated by piperonyl butoxide and menadione in rats. Part II: genotoxic and cytotoxic potential.

    Science.gov (United States)

    Arslan, Mehmet; Sevgiler, Yusuf; Buyukleyla, Mehmet; Yardimci, Mustafa; Yilmaz, Mehmet; Rencuzogullari, Eyyup

    2016-01-01

    Despite its intended use, imidacloprid causes genotoxic and cytotoxic effects in mammals, especially in the presence of metabolic activation systems. The aim of this study was to determine to which extent these effects are sex related and how its metabolism modulators piperonyl butoxide and menadione affect its toxicity. Male and female Sprague-Dawley rats were injected with the intraperitoneal LD50 dose of imidacloprid alone (170 mg/kg) or pretreated with piperonyl butoxide (100 mg/kg) and menadione (25 mg/kg) for 12 and 24 h. Structural chromosome aberrations, abnormal cells and mitotic index were determined microscopically in bone marrow cells. Male rats showed susceptibility to the genotoxic effects of imidacloprid. Piperonyl butoxide was effective in countering this effect only at 24 h, whereas menadione exacerbated imidacloprid-induced genotoxicity. Piperonyl butoxide and menadione pretreatments increased the percentage of structural chromosome aberrations and abnormal cells in females. Imidacloprid decreased the mitotic index, whereas pretreatment with piperonyl butoxide and menadione showed improvement in both sexes. We believe that CYP450-mediated metabolism of imidacloprid is under the hormonal control and therefore that its genotoxicity is sex related. Piperonyl butoxide pretreatment also showed sex-related modulation. The hormonal effects on imidacloprid biotransformation require further investigation.

  11. Novel insights into the antiproliferative effects and synergism of quercetin and menadione in human leukemia Jurkat T cells.

    Science.gov (United States)

    Baran, Irina; Ionescu, Diana; Filippi, Alexandru; Mocanu, Maria Magdalena; Iftime, Adrian; Babes, Ramona; Tofolean, Ioana Teodora; Irimia, Ruxandra; Goicea, Alexandru; Popescu, Valentin; Dimancea, Alexandru; Neagu, Andrei; Ganea, Constanta

    2014-07-01

    The flavonoid quercetin and menadione (vitamin K3) are known as potent apoptogens in human leukemia Jurkat T cells. We explored some underlying mechanisms and the potential relevance of the combination quercetin-menadione for clinical applications. In acute treatments, quercetin manifested a strong antioxidant character, but induced a transient loss of Δψm, likely mediated by opening of the mitochondrial permeability transition pore. After removal of quercetin, persistent mitochondrial hyperpolarization was generated via stimulation of respiratory Complex I. In contrast, menadione-induced Δψm dissipation was only partially and transiently reversed after menadione removal. Results indicate that Ca(2+) release is a necessary event in quercetin-induced cell death and that the survival response to quercetin is delineated within 1h from exposure. Depending on dose, the two agents exhibited either antagonistic or synergistic effects in reducing clonogenicity of Jurkat cells. 24-h combinatorial regimens at equimolar concentrations of 10-15 μM, which are compatible with a clinically achievable (and safe) scheme, reduced cell viability at efficient rates. Altogether, these findings support the idea that the combination quercetin-menadione could improve the outcome of conventional leukemia therapies, and warrant the utility of additional studies to investigate the therapeutic effects of this combination in different cellular or animal models for leukemia. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Study of charge transfer complexes of menadione (vitamin K 3) with a series of anilines

    Science.gov (United States)

    Pal, Purnendu; Saha, Avijit; Mukherjee, Asok K.; Mukherjee, Dulal C.

    2004-01-01

    Menadione (vitamin K 3) has been shown to form charge transfer complexes with N, N-dimethyl aniline, N, N-dimethyl p-toluidine and N, N-dimethyl m-toluidine in CCl 4 medium. The CT transition energies are well correlated with the ionisation potentials of the anilines. The formation constants of the complexes have been determined at a number of temperatures from which the enthalpies and entropies of formation have been obtained. The formation constants exhibit a very good linear free energy relationship (Hammett) at all the temperatures studied.

  13. Vitamin E decreases extra-hepatic menaquinone-4 concentrations in rats fed menadione or phylloquinone.

    Science.gov (United States)

    Farley, Sherry M; Leonard, Scott W; Labut, Edwin M; Raines, Hannah F; Card, David J; Harrington, Dominic J; Mustacich, Debbie J; Traber, Maret G

    2012-06-01

    The mechanism for increased bleeding and decreased vitamin K status accompanying vitamin E supplementation is unknown. We hypothesized that elevated hepatic α-tocopherol (α-T) concentrations may stimulate vitamin K metabolism and excretion. Furthermore, α-T may interfere with the side chain removal of phylloquinone (PK) to form menadione (MN) as an intermediate for synthesis of tissue-specific menaquinone-4 (MK-4). In order to investigate these hypotheses, rats were fed phylloquinone (PK) or menadione (MN) containing diets (2 μmol/kg) for 2.5 weeks. From day 10, rats were given daily subcutaneous injections of either α-T (100 mg/kg) or vehicle and were sacrificed 24 h after the seventh injection. Irrespective of diet, α-T injections decreased MK-4 concentrations in brain, lung, kidney, and heart; and PK in lung. These decreases were not accompanied by increased excretion of urinary 5C- or 7C-aglycone vitamin K metabolites, however, the urinary α-T metabolite (α-CEHC) increased ≥ 100-fold. Moreover, α-T increases were accompanied by downregulation of hepatic cytochrome P450 expression and modified expression of tissue ATP-binding cassette transporters. Thus, in rats, high tissue α-T depleted tissue MK-4 without significantly increasing urinary vitamin K metabolite excretion. Changes in tissue MK-4 and PK levels may be a result of altered regulation of transporters. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Rapeseed oil-rich diet alters in vitro menadione and nimesulide hepatic mitochondrial toxicity.

    Science.gov (United States)

    Monteiro, João P; Silva, Ana M; Jurado, Amália S; Oliveira, Paulo J

    2013-10-01

    Diet-induced changes in the lipid composition of mitochondrial membranes have been shown to influence physiological processes. However, the modulation effect of diet on mitochondrially-active drugs has not yet received the deserved attention. Our hypothesis is that modulation of membrane dynamics by diet impacts drug-effects on liver mitochondrial functioning. In a previous work, we have shown that a diet rich in rapeseed oil altered mitochondrial membrane composition and bioenergetics in Wistar rats. In the present work, we investigated the influence of the modified diet on hepatic mitochondrial activity of two drugs, menadione and nimesulide, and FCCP, a classic protonophore, was used for comparison. The results showed that the effects of menadione and nimesulide were less severe on liver mitochondria for rats fed the modified diet than on rats fed the control diet. A specific effect on complex I seemed to be involved in drug-induced mitochondria dysfunction. Liver mitochondria from the modified diet group were more susceptible to nimesulide effects on MPT induction. The present work demonstrates that diet manipulation aimed at modifying mitochondrial membrane properties alters the toxicity of mitochondria active agents. This work highlights that diet may potentiate mitochondrial pharmacologic effects or increase drug-induced liabilities. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Screening test for rapid food safety evaluation by menadione-catalysed chemiluminescent assay.

    Science.gov (United States)

    Yamashoji, Shiro; Yoshikawa, Naoko; Kirihara, Masayuki; Tsuneyoshi, Toshihiro

    2013-06-15

    The chemiluminescent assay of menadione-catalysed H2O2 production by living mammalian cells was proposed to be useful for rapid food safety evaluation. The tested foods were extracted with water, ethanol and dimethylsulfoxide, and each extract was incubated with NIH3T3, Neuro-2a and HepG2 cells for 4h. Menadione-catalysed H2O2 production by living mammalian cells exposed to each extract was determined by the chemiluminescent assay requiring only 10 min, and the viability of the cells was estimated as percentage based on H2O2 production by intact cells. In this study the cytotoxicity of food was rated in order of inhibitory effect on H2O2 production by intact cells. The well known natural toxins such as Fusarium mycotoxin, tomato toxin tomatine, potato toxin solanine and marine toxins terodotoxin and brevetoxin could be detected by the above chemiluminescent assay. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. Nicotine prevents the apoptosis induced by menadione in human lung cancer cells

    International Nuclear Information System (INIS)

    Zhang Tao; Lu Heng; Shang Xuan; Tian Yihao; Zheng Congyi; Wang Shiwen; Cheng Hanhua; Zhou Rongjia

    2006-01-01

    Approximately 50% of long-term cigarette smokers die prematurely from the adverse effects of smoking, including on lung cancer and other illnesses. Nicotine is a main component in tobacco and has been implicated as a potential factor in the pathogenesis of human lung cancer. However, the mechanism of nicotine action in the development of lung cancer remains largely unknown. In the present study, we designed a nicotine-apoptosis system, by pre-treatment of nicotine making lung cancer cell A549 to be in a physiological nicotine environment, and observed that nicotine promoted cell proliferation and prevented the menadione-induced apoptosis, and exerts its role of anti-apoptosis by shift of apoptotic stage induced by menadione from late apoptotic stage to early apoptotic stage, in which NF-κB was up-regulated. Interference analysis of NF-κB in A549 cells showed that knock down of NF-κB resulted in apoptosis promotion and counteracted the protective effect of nicotine. The findings suggest that nicotine has potential effect in lung cancer genesis, especially in patients with undetectable early tumor development and development of specific NF-κB inhibitors would represent a potentially exciting new pharmacotherapy for tobacco-related lung cancer

  17. Menadione-mediated WST1 reduction assay for the determination of metabolic activity of cultured neural cells.

    Science.gov (United States)

    Stapelfeldt, Karsten; Ehrke, Eric; Steinmeier, Johann; Rastedt, Wiebke; Dringen, Ralf

    2017-12-01

    Cellular reduction of tetrazolium salts to their respective formazans is frequently used to determine the metabolic activity of cultured cells as an indicator of cell viability. For membrane-impermeable tetrazolium salts such as WST1 the application of a membrane-permeable electron cycler is usually required to mediate the transfer of intracellular electrons for extracellular WST1 reduction. Here we demonstrate that in addition to the commonly used electron cycler M-PMS, menadione can also serve as an efficient electron cycler for extracellular WST1 reduction in cultured neural cells. The increase in formazan absorbance in glial cell cultures for the WST1 reduction by menadione involves enzymatic menadione reduction and was twice that recorded for the cytosolic enzyme-independent WST1 reduction in the presence of M-PMS. The optimized WST1 reduction assay allowed within 30 min of incubation a highly reliable detection of compromised cell metabolism caused by 3-bromopyruvate and impaired membrane integrity caused by Triton X-100, with a sensitivity as good as that of spectrophotometric assays which determine cellular MTT reduction or lactate dehydrogenase release. The short incubation period of 30 min and the observed good sensitivity make this optimized menadione-mediated WST1 reduction assay a quick and reliable alternative to other viability and toxicity assays. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Calixarene capped ZnS quantum dots as an optical nanoprobe for detection and determination of menadione.

    Science.gov (United States)

    Joshi, Kuldeep V; Joshi, Bhoomika K; Pandya, Alok; Sutariya, Pinkesh G; Menon, Shobhana K

    2012-10-21

    In this communication we report a p-sulfonatocalix[4]arene coated ZnS quantum dots "cup type" highly stable optical probe for the detection and determination of menadione (VK(3)) with high sensitivity and selectivity. The detection of VK(3) depends on supramolecular host-guest chemistry.

  19. Quantification of menadione from plasma and urine by a novel cysteamine-derivatization based UPLC-MS/MS method.

    Science.gov (United States)

    Yuan, Teng-Fei; Wang, Shao-Ting; Li, Yan

    2017-09-15

    Menadione, as the crucial component of vitamin Ks, possessed significant nutritional and clinical values. However, there was still lack of favourable quantification strategies for it to date. For improvement, a novel cysteamine derivatization based UPLC-MS/MS method was presented in this work. The derivatizating reaction was proved non-toxic, easy-handling and high-efficient, which realized the MS detection of menadione under positive mode. Benefitting from the excellent sensitivity of the derivatizating product as well as the introduction of the stable isotope dilution technique, the quantification could be achieved in the range of 0.05-50.0ng/mL for plasma and urine matrixes with satisfied accuracy and precision. After analysis of the samples from healthy volunteers after oral administration of menadione sodium bisulfite tablets, the urinary free menadione was quantified for the very first time. We believe the progress in this work could largely promote the exploration of the metabolic mechanism of vitamin K in vivo. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Oxidative stress protection and glutathione metabolism in response to hydrogen peroxide and menadione in riboflavinogenic fungus Ashbya gossypii.

    Science.gov (United States)

    Kavitha, S; Chandra, T S

    2014-11-01

    Ashbya gossypii is a plant pathogen and a natural overproducer of riboflavin and is used for industrial riboflavin production. A few literature reports depict a link between riboflavin overproduction and stress in this fungus. However, the stress protection mechanisms and glutathione metabolism are not much explored in A. gossypii. In the present study, an increase in the activity of catalase and superoxide dismutase was observed in response to hydrogen peroxide and menadione. The lipid peroxide and membrane lipid peroxide levels were increased by H2O2 and menadione, indicating oxidative damage. The glutathione metabolism was altered with a significant increase in oxidized glutathione (GSSG), glutathione peroxidase (GPX), glutathione S transferase (GST), and glutathione reductase (GR) and a decrease in reduced glutathione (GSH) levels in the presence of H2O2 and menadione. Expression of the genes involved in stress mechanism was analyzed in response to the stressors by semiquantitative RT-PCR. The messenger RNA (mRNA) levels of CTT1, SOD1, GSH1, YAP1, and RIB3 were increased by H2O2 and menadione, indicating the effect of stress at the transcriptional level. A preliminary bioinformatics study for the presence of stress response elements (STRE)/Yap response elements (YRE) depicted that the glutathione metabolic genes, stress genes, and the RIB genes hosted either STRE/YRE, which may enable induction of these genes during stress.

  1. α-Syntrophin is involved in the survival signaling pathway in myoblasts under menadione-induced oxidative stress.

    Science.gov (United States)

    Lim, Jeong-A; Choi, Su Jin; Moon, Jae Yun; Kim, Hye Sun

    2016-05-15

    Dystrophin-deficient muscle is known to be more vulnerable to oxidative stress, but not much is known about the signaling pathway(s) responsible for this phenomenon. α-Syntrophin, a component of the dystrophin-glycoprotein complex, can function as a scaffold protein because of its multiple protein interaction domains. In this study, we investigated the role of α-syntrophin in C2 myoblasts under menadione-induced oxidative stress. We found that the protein level of α-syntrophin was elevated when cells were exposed to menadione. To investigate the function of α-syntrophin during oxidative stress, we established α-syntrophin-overexpressing and knockdown cell lines. The α-syntrophin-overexpressing cells were resistant to the menadione-induced oxidative stress. In addition, survival signalings such as protein kinase B (Akt) phosphorylation and the Bcl-2/BAX ratio were increased in these cells. On the other hand, apoptotic signals such as cleavage of caspase-3 and poly ADP ribose polymerase (PARP) were increased in the α-syntrophin knockdown cells. Furthermore, Ca(2+)influx, which is known to increase when cells are exposed to oxidative stress, decreased in the α-syntrophin-overexpressing cells, but increased in the knockdown cells. These results suggest that α-syntrophin plays a pivotal role in the survival pathway triggered by menadione-induced oxidative stress in cultured myoblasts. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. A novel screening method based on menadione mediated rapid reduction of tetrazolium salt for testing of anti-mycobacterial agents.

    Science.gov (United States)

    Singh, Upasana; Akhtar, Shamim; Mishra, Abhishek; Sarkar, Dhiman

    2011-02-01

    A microplate-based rapid, inexpensive and robust technique is developed by using tetrazolium salt 2,3-bis[2-methyloxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide (XTT) and menadione to determine the viability of Mycobacterium tuberculosis, Mycobacterium bovis BCG and Mycobacterium smegmatis bacilli in microplate format. In general, XTT reduction is an extremely slow process which takes almost 24 h to produce a detectable signal. Menadione could drastically induce this reduction to an almost equal extent within a few minutes in a dose dependent manner. The reduction of XTT is directly proportional to the cell concentration in the presence of menadione. The standardized protocol used 200 μM of XTT and 60 μM of menadione in 250 μl of cell suspension grown either in aerobic or anaerobic conditions. The cell suspension of M. bovis BCG and M. tuberculosis were incubated for 40 min before reading the optical density at 470 nm whereas M. smegmatis was incubated for 20 min. Calculated Signal/Noise (S/N) ratios obtained by applying this protocol were 5.4, 6.4 and 9.4 using M. bovis BCG, M. tuberculosis and M. smegmatis respectively. The calculated Z' factors were >0.8 for all mycobacterium bacilli indicating the robustness of the XTT Reduction Menadione Assay (XRMA) for rapid screening of inhibitors. The assay protocol was validated by applying 10 standard anti-tubercular agents on M. tuberculosis, M. bovis BCG and M. smegmatis. The Minimum Inhibitory Concentration (MIC) values were found to be similar to reported values from Colony Forming Unit (CFU) and REMA (resazurin microplate assay) assays. Altogether, XRMA is providing a novel anti-tubercular screening protocol which could be useful in high throughput screening programs against different physiological stages of the bacilli. Copyright © 2010 Elsevier B.V. All rights reserved.

  3. Ursolic Acid-enriched herba cynomorii extract induces mitochondrial uncoupling and glutathione redox cycling through mitochondrial reactive oxygen species generation: protection against menadione cytotoxicity in h9c2 cells.

    Science.gov (United States)

    Chen, Jihang; Wong, Hoi Shan; Ko, Kam Ming

    2014-01-27

    Herba Cynomorii (Cynomorium songaricum Rupr., Cynomoriaceae) is one of the most commonly used 'Yang-invigorating' tonic herbs in Traditional Chinese Medicine (TCM). An earlier study in our laboratory has demonstrated that HCY2, an ursolic acid-enriched fraction derived from Herba Cynomorii, increased mitochondrial ATP generation capacity (ATP-GC) and induced mitochondrial uncoupling as well as a cellular glutathione response, thereby protecting against oxidant injury in H9c2 cells. In this study, we demonstrated that pre-incubation of H9c2 cells with HCY2 increased mitochondrial reactive oxygen species (ROS) generation in these cells, which is likely an event secondary to the stimulation of the mitochondrial electron transport chain. The suppression of mitochondrial ROS by the antioxidant dimethylthiourea abrogated the HCY2-induced enhancement of mitochondrial uncoupling and glutathione reductase (GR)-mediated glutathione redox cycling, and also protected against menadione-induced cytotoxicity. Studies using specific inhibitors of uncoupling protein and GR suggested that the HCY2-induced mitochondrial uncoupling and glutathione redox cycling play a determining role in the cytoprotection against menadione-induced oxidant injury in H9c2 cells. Experimental evidence obtained thus far supports the causal role of HCY2-induced mitochondrial ROS production in eliciting mitochondrial uncoupling and glutathione antioxidant responses, which offer cytoprotection against oxidant injury in H9c2 cells.

  4. Synergistic reduction of toluylene blue induced by acetaldehyde and menadione in yeast cell suspension: Application to determination of yeast cell activity

    Directory of Open Access Journals (Sweden)

    Shiro Yamashoji

    2017-03-01

    Full Text Available Membrane permeant acetaldehyde and menadione induced the synergistic reduction of toluylene blue (TB acting as non-membrane permeant redox indicator in yeast cell suspension. NADH and acetaldehyde also induced the synergistic TB reduction in permeabilized yeast cells and phosphate buffer, but menadione had no ability to promote TB reduction. The pre-incubation of acetaldehyde inhibited the above synergistic reduction of TB in intact and permeabilized yeast cell suspension. The pre-incubation of acetaldehyde might promote NADH oxidation by alcohol dehydrogenase, because acetaldehyde decreased the intracellular NAD(PH concentration. The above facts indicate that the synergistic reduction of TB is controlled by the order of addition of menadione and acetaldehyde. The synergistic reduction of TB by menadione and acetaldehyde was proportional to viable yeast cell number from 104 to 2×106 cells/ml, and this assay was applicable to cytotoxicity test. The time required for the above assay was only 2 min.

  5. The effect of menadione on glutathione S-transferase A1 (GSTA1): c-Jun N-terminal kinase (JNK) complex dissociation in human colonic adenocarcinoma Caco-2 cells.

    Science.gov (United States)

    Adnan, Humaira; Antenos, Monica; Kirby, Gordon M

    2012-10-02

    Glutathione S-transferases (GSTs) act as modulators of mitogen-activated protein kinase signal transduction pathways via a mechanism involving protein-protein interactions. We have demonstrated that GSTA1 forms complexes with JNK and modifies JNK activation during cellular stress, but the factors that influence complex association and dissociation are unknown. We hypothesized that menadione causes dissociation of GSTA1-JNK complexes, activates JNK, and the consequences of menadione exposure depend on GSTA1 expression. We demonstrate that menadione causes GSTA1-JNK dissociation and JNK activation in preconfluent Caco-2 cells, whereas postconfluent cells are resistant to this effect. Moreover, preconfluent cells are more sensitive than postconfluent cells to menadione-induced cytotoxicity. Activation of JNK is transient since removal of menadione causes GSTA1 to re-associate with JNK reducing cytotoxicity. Over-expression and knockdown of GSTA1 did not alter JNK activation by menadione or sensitivity to menadione-induced cytotoxicity. These results indicate that GSTA1-JNK complex integrity does not affect the ability of menadione to activate JNK. N-acetyl cysteine prevents GSH depletion and blocks menadione-induced complex dissociation, JNK activation and inhibits menadione-induced cytotoxicity. JNK activation and inhibits menadione-induced cytotoxicity. The data suggest that the mechanism of menadione-induced JNK activation involves the production of reactive oxygen species, likely superoxide anion, and intracellular GSH levels play an important role in preventing GSTA1-JNK complex dissociation, subsequent JNK activation and induction of cytotoxicity. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  6. Effects of gamma radiation and menadione (vit. K3) on dissolution and dimerization of δ-tocopherol

    International Nuclear Information System (INIS)

    Kupczyk, B.; Gogolewski, M.

    1997-01-01

    Effect of ionizing radiation and menadione (vit. K 3 ) on dissolution and dimerization of δ-tocopherol was studied. Mixture of δ-tocopherol and menadione (vit. K 3 ) dissolved in benzene, ethanol or used in substantia were irradiated at 2.5, 5, 10, 20 kGy dose using Co-60 as a radiation source. Dissolution of δ-tocopherol in substantia was lower then disintegration of δ-tocopherol dissolved in benzene or in ethanol. However, we did not observe any significant difference between dissolution of δ-tocopherol in both studied solvents. The number of formed dimers of δ-tocopherol were different for all three cases tested. The quantities of δ-tocopherol dimers were dependent on radiation dose. (author)

  7. ompW is cooperatively upregulated by MarA and SoxS in response to menadione.

    Science.gov (United States)

    Collao, B; Morales, E H; Gil, F; Calderón, I L; Saavedra, C P

    2013-04-01

    OmpW is a minor porin whose biological function has not been clearly defined. Evidence obtained in our laboratory indicates that in Salmonella enterica serovar Typhimurium the expression of OmpW is activated by SoxS upon exposure to paraquat and it is required for resistance. SoxS belongs to the AraC family of transcriptional regulators, like MarA and Rob. Due to their high structural similarity, the genes under their control have been grouped in the mar/sox/rob regulon, which presents a DNA-binding consensus sequence denominated the marsox box. In this work, we evaluated the role of the transcription factors MarA, SoxS and Rob of S. enterica serovar Typhimurium in regulating ompW expression in response to menadione. We determined the transcript and protein levels of OmpW in different genetic backgrounds; in the wild-type and Δrob strains ompW was upregulated in response to menadione, while in the ΔmarA and ΔsoxS strains the induction was abolished. In a double marA soxS mutant, ompW transcript levels were lowered after exposure to menadione, and only complementation in trans with both genes restored the positive regulation. Using transcriptional fusions and electrophoretic mobility shift assays with mutant versions of the promoter region we demonstrated that two of the predicted sites were functional. Additionally, we demonstrated that MarA increases the affinity of SoxS for the ompW promoter region. In conclusion, our study shows that ompW is upregulated in response to menadione in a cooperative manner by MarA and SoxS through a direct interaction with the promoter region.

  8. NAD(P)H-dependent quinone oxidoreductase 1 (NQO1) and cytochrome P450 oxidoreductase (CYP450OR) differentially regulate menadione-mediated alterations in redox status, survival and metabolism in pancreatic β-cells.

    Science.gov (United States)

    Gray, Joshua P; Karandrea, Shpetim; Burgos, Delaine Zayasbazan; Jaiswal, Anil A; Heart, Emma A

    2016-11-16

    NQO1 (NAD(P)H-quinone oxidoreductase 1) reduces quinones and xenobiotics to less-reactive compounds via 2-electron reduction, one feature responsible for the role of NQO1 in antioxidant defense in several tissues. In contrast, NADPH cytochrome P450 oxidoreductase (CYP450OR), catalyzes the 1-electron reduction of quinones and xenobiotics, resulting in enhanced superoxide formation. However, to date, the roles of NQO1 and CYP450OR in pancreatic β-cell metabolism under basal conditions and oxidant challenge have not been characterized. Using NQO1 inhibition, over-expression and knock out, we have demonstrated that, in addition to protection of β-cells from toxic concentrations of the redox cycling quinone menadione, NQO1 also regulates the basal level of reduced-to-oxidized nucleotides, suggesting other role(s) beside that of an antioxidant enzyme. In contrast, over-expression of NADPH cytochrome P450 oxidoreductase (CYP450OR) resulted in enhanced redox cycling activity and decreased cellular viability, consistent with the enhanced generation of superoxide and H 2 O 2 . Basal expression of NQO1 and CYP450OR was comparable in isolated islets and liver. However, NQO1, but not CYP450OR, was strongly induced in β-cells exposed to menadione. NQO1 and CYP450OR exhibited a reciprocal preference for reducing equivalents in β-cells: while CYP450OR preferentially utilized NADPH, NQO1 primarily utilized NADH. Together, these results demonstrate that NQO1 and CYP450OR reciprocally regulate oxidant metabolism in pancreatic β-cells. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  9. Menadione induces G2/M arrest in gastric cancer cells by down-regulation of CDC25C and proteasome mediated degradation of CDK1 and cyclin B1

    Science.gov (United States)

    Lee, Min Ho; Cho, Yoonjung; Kim, Do Hyun; Woo, Hyun Jun; Yang, Ji Yeong; Kwon, Hye Jin; Yeon, Min Ji; Park, Min; Kim, Sa-Hyun; Moon, Cheol; Tharmalingam, Nagendran; Kim, Tae Ue; Kim, Jong-Bae

    2016-01-01

    Menadione (vitamin K3) has been reported to induce apoptotic cell death and growth inhibition in various types of cancer cells. However, involvement of menadione in cell cycle control has not been considered in gastric cancer cells yet. In the current study, we have investigated whether menadione is involved in the cell cycle regulation and suppression of growth in gastric cancer cells. In the cell cycle analysis, we found that menadione induced G2/M cell cycle arrest in AGS cells. To elucidate the underlying mechanism, we investigated the cell cycle regulatory molecules involved in the G2/M cell cycle transition. After 24 h of menadione treatment, the protein level of CDK1, CDC25C and cyclin B1 in AGS cells was decreased in a menadione dose-dependent manner. In the time course experiment, the protein level of CDC25C decreased in 6 h, and CDK1and cyclin B1 protein levels began to decrease after 18 h of menadione treatment. We found that mRNA level of CDC25C decreased by menadione treatment in 6 h. Menadione did not have an influence on mRNA level of CDK1 and cyclin B1 though the protein levels were decreased. However, the decreased protein levels of CDK1 and cyclin B1 were recovered by inhibition of proteasome. Collectively, these results suggest that menadione inhibits growth of gastric cancer cells by reducing expression of CDC25C and promoting proteasome mediated degradation of CDK1 and cyclin B1 thereby blocking transition of the cell cycle from G2 phase to M phase. PMID:28077999

  10. Mitochondrial dysfunction is responsible for the intestinal calcium absorption inhibition induced by menadione.

    Science.gov (United States)

    Marchionatti, Ana M; Perez, Adriana V; Diaz de Barboza, Gabriela E; Pereira, Beatriz M; Tolosa de Talamoni, Nori G

    2008-02-01

    Menadione (MEN) inhibits intestinal calcium absorption by a mechanism not completely understood. The aim of this work was to find out the role of mitochondria in this inhibitory mechanism. Hence, normal chicks treated with one i.p. dose of MEN were studied in comparison with controls. Intestinal calcium absorption was measured by the in situ ligated intestinal segment technique. GSH, oxidoreductase activities from the Krebs cycle and enzymes of the antioxidant system were measured in isolated mitochondria. Mitochondrial membrane potential was measured by a flow cytometer technique. DNA fragmentation and cytochrome c localization were determined by immunocytochemistry. Data indicate that in 30 min, MEN decreases intestinal Ca(2+) absorption, which returns to the control values after 10 h. GSH was only decreased for half an hour, while the activity of malate dehydrogenase and alpha-ketoglutarate dehydrogenase was diminished for 48 h. Mn(2+)-superoxide dismutase activity was increased in 30 min, whereas the activity of catalase and glutathione peroxidase remained unaltered. DNA fragmentation and cytochrome c release were maximal in 30 min, but were recovered after 15 h. In conclusion, MEN inhibits intestinal Ca(2+) absorption by mitochondrial dysfunction as revealed by GSH depletion and alteration of the permeability triggering the release of cytochrome c and DNA fragmentation.

  11. Aqueous two-phase system purification for superoxide dismutase induced by menadione from Phanerochaete chrysosporium.

    Science.gov (United States)

    Kavakcıoğlu, Berna; Tongul, Burcu; Tarhan, Leman

    2017-03-01

    In the present work, the partitioning behavior of menadione-induced superoxide dismutase (SOD; EC 1.15.1.1), an antioxidant enzyme that has various applications in the medical and cosmetic industries, from the white rot fungus Phanerochaete chrysosporium has been characterized on different types of aqueous two-phase systems (ATPSs) (poly(ethylene glycol)/polypropylene glycol (PEG/PPG)-dextran, PEG-salt and PPG-salt). PEG-salt combinations were found most optimal systems for the purification of SOD. The best partition conditions were found using the PEG-3350 24% and K 2 HPO 4 5% (w/w) with pH 7.0 at 25 °C. The partition coefficient of total SOD activity and total protein concentration observed in this system were 0.17 and 6.65, respectively, with the recovery percentage as 78.90% in the bottom phase and 13.17% in the top phase. The highest purification fold for SOD from P. chrysosporium was found as 6.04 in the bottom phase of PEG 3350%24 - K 2 HPO 4 %5 (w/w) system with pH 7.0. SOD purified from P. chrysosporium was determined to be a homodimer in its native state with a molecular weight of 60  ± 4 kDa. Consequently, simple and only one step PEG-salt ATPS system was developed for SOD purification from P. chrysosporium.

  12. Sex-, tissue-, and exposure duration-dependent effects of imidacloprid modulated by piperonyl butoxide and menadione in rats. Part I: oxidative and neurotoxic potentials.

    Science.gov (United States)

    Yardimci, Mustafa; Sevgiler, Yusuf; Rencuzogullari, Eyyup; Arslan, Mehmet; Buyukleyla, Mehmet; Yilmaz, Mehmet

    2014-12-01

    Earlier research has evidenced the oxidative and neurotoxic potential of imidacloprid, a neonicotinoid insecticide, in different animal species. The primary aim of this study was to determine how metabolic modulators piperonyl butoxide and menadione affect imidacloprid's adverse action in the liver and kidney of Sprague-Dawley rats of both sexes. The animals were exposed to imidacloprid alone (170 mg kg⁻¹) or in combination with piperonyl butoxide (100 mg kg⁻¹) or menadione (25 mg kg⁻¹) for 12 and 24 h. Their liver and kidney homogenates were analysed spectrophotometrically for glutathione peroxidase, glutathione S-transferase, catalase, total cholinesterase specific activities, total glutathione, total protein content, and lipid peroxidation levels. Imidacloprid displayed its prooxidative and neurotoxic effects predominantly in the kidney of male rats after 24 h of exposure. Our findings suggest that the observed differences in prooxidative and neurotoxic potential of imidacloprid could be related to differences in its metabolism between the sexes. Co-exposure (90-min pre-treatment) with piperonyl butoxide or menadione revealed tissue-specific effect of imidacloprid on total cholinesterase activity. Increased cholinesterase activity in the kidney could be an adaptive response to imidacloprid-induced oxidative stress. In the male rat liver, co-exposure with piperonyl butoxide or menadione exacerbated imidacloprid toxicity. In female rats, imidacloprid+menadione co-exposure caused prooxidative effects, while no such effects were observed with imidacloprid alone or menadione alone. In conclusion, sex-, tissue-, and duration-specific effects of imidacloprid are remarkable points in its toxicity.

  13. Betamethasone augments the antifungal effect of menadione--towards a novel anti-Candida albicans combination therapy.

    Science.gov (United States)

    Jakab, Ágnes; Emri, Tamás; Sipos, Lilla; Kiss, Ágnes; Kovács, Renátó; Dombrádi, Viktor; Kemény-Beke, Ádám; Balla, József; Majoros, László; Pócsi, István

    2015-08-01

    The fluorinated glucocorticoid betamethasone stimulated both the extracellular phospholipase production and hypha formation of the opportunistic human pathogen Candida albicans and also decreased the efficiency of the polyene antimycotics amphotericin B and nystatin against C. albicans in a dose-dependent manner. Importantly, betamethasone increased synergistically the anti-Candida activity of the oxidative stress generating agent menadione, which may be exploited in future combination therapies to prevent or cure C. albicans infections, in the field of dermatology. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Identification of point mutations in clinical Staphylococcus aureus strains that produce small-colony variants auxotrophic for menadione.

    Science.gov (United States)

    Dean, Melissa A; Olsen, Randall J; Long, S Wesley; Rosato, Adriana E; Musser, James M

    2014-04-01

    Staphylococcus aureus small-colony variants (SCVs) are implicated in chronic and relapsing infections that are difficult to diagnose and treat. Despite many years of study, the underlying molecular mechanisms and virulence effect of the small-colony phenotype remain incompletely understood. We sequenced the genomes of five S. aureus SCV strains recovered from human patients and discovered previously unidentified nonsynonymous point mutations in three genes encoding proteins in the menadione biosynthesis pathway. Analysis of genetic revertants and complementation with wild-type alleles confirmed that these mutations caused the SCV phenotype and decreased virulence for mice.

  15. Menadione (vitamin K3) is a catabolic product of oral phylloquinone (vitamin K1) in the intestine and a circulating precursor of tissue menaquinone-4 (vitamin K2) in rats.

    Science.gov (United States)

    Hirota, Yoshihisa; Tsugawa, Naoko; Nakagawa, Kimie; Suhara, Yoshitomo; Tanaka, Kiyoshi; Uchino, Yuri; Takeuchi, Atsuko; Sawada, Natsumi; Kamao, Maya; Wada, Akimori; Okitsu, Takashi; Okano, Toshio

    2013-11-15

    Mice have the ability to convert dietary phylloquinone (vitamin K1) into menaquinone-4 (vitamin K2) and store the latter in tissues. A prenyltransferase enzyme, UbiA prenyltransferase domain-containing 1 (UBIAD1), is involved in this conversion. There is evidence that UBIAD1 has a weak side chain cleavage activity for phylloquinone but a strong prenylation activity for menadione (vitamin K3), which has long been postulated as an intermediate in this conversion. Further evidence indicates that when intravenously administered in mice phylloquinone can enter into tissues but is not converted further to menaquinone-4. These findings raise the question whether phylloquinone is absorbed and delivered to tissues in its original form and converted to menaquinone-4 or whether it is converted to menadione in the intestine followed by delivery of menadione to tissues and subsequent conversion to menaquinone-4. To answer this question, we conducted cannulation experiments using stable isotope tracer technology in rats. We confirmed that the second pathway is correct on the basis of structural assignments and measurements of phylloquinone-derived menadione using high resolution MS analysis and a bioassay using recombinant UBIAD1 protein. Furthermore, high resolution MS and (1)H NMR analyses of the product generated from the incubation of menadione with recombinant UBIAD1 revealed that the hydroquinone, but not the quinone form of menadione, was an intermediate of the conversion. Taken together, these results provide unequivocal evidence that menadione is a catabolic product of oral phylloquinone and a major source of tissue menaquinone-4.

  16. Combined calcitriol and menadione reduces experimental murine triple negative breast tumor.

    Science.gov (United States)

    Bohl, Luciana; Guizzardi, Solange; Rodríguez, Valeria; Hinrichsen, Lucila; Rozados, Viviana; Cremonezzi, David; Tolosa de Talamoni, Nori; Picotto, Gabriela

    2017-10-01

    Calcitriol (D) or 1,25(OH) 2 D 3 inhibits the growth of several tumor cells including breast cancer cells, by activating cell death pathways. Menadione (MEN), a glutathione-depleting compound, may be used to potentiate the antiproliferative actions of D on cancer cells. We have previously shown in vitro that MEN improved D-induced growth arrest on breast cancer cell lines, inducing oxidative stress and DNA damage via ROS generation. Treatment with MEN+D resulted more effective than D or MEN alone. To study the in vivo effect of calcitriol, MEN or their combination on the development of murine transplantable triple negative breast tumor M-406 in its syngeneic host. Tumor M-406 was inoculated s.c., and when tumors reached the desired size, animals were randomly assigned to one of four groups receiving daily i.p. injections of either sterile saline solution (controls, C), MEN, D, or both (MEN+D). Body weight and tumor volume were recorded three times a week. Serum calcium was determined before and at the end of the treatment, at which time tumor samples were obtained for histological examination. None of the drugs, alone or in combination, affected mice body weight in the period studied. The combined treatment reduced tumor growth rate (C vs. MEN+D, P<0.05) and the corresponding histological sections exhibited small remaining areas of viable tumor only in the periphery. A concomitant DNA fragmentation was observed in all treated groups and MEN potentiated the calcitriol effect on tumor growth. As previously observed in vitro, treatment with MEN and D delayed tumor growth in vivo more efficiently than the individual drugs, with evident signals of apoptosis induction. Our results propose an alternative protocol to treat triple negative breast cancer, using GSH depleting drugs together with calcitriol, which would allow lower doses of the steroid to maintain the antitumor effect while diminishing its adverse pharmacological effects. Copyright © 2017. Published by

  17. Antioxidant deficit in gills of Pacific oyster (Crassostrea gigas) exposed to chlorodinitrobenzene increases menadione toxicity

    International Nuclear Information System (INIS)

    Trevisan, Rafael; Arl, Miriam; Sacchet, Cássia Lopes; Engel, Cristiano Severino; Danielli, Naissa Maria; Mello, Danielle Ferraz; Brocardo, Caroline; Maris, Angelica Francesca; Dafre, Alcir Luiz

    2012-01-01

    Disturbances in antioxidant defenses decrease cellular protection against oxidative stress and jeopardize cellular homeostasis. To knock down the antioxidant defenses of Pacific oyster Crassostrea gigas, animals were pre-treated with 1-chloro-2,4-dinitrobenzene (CDNB) and further challenged with pro-oxidant menadione (MEN). CDNB pre-treatment (10 μM for 18 h) was able to consume cellular thiols in gills, decreasing GSH (53%) and decrease protein thiols (25%). CDNB pre-treatment also disrupted glutathione reductase and thioredoxin reductase activity in the gills, but likewise strongly induced glutathione S-transferase activity (270% increase). Surprisingly, hemocyte viability was greatly affected 24 h after CDNB removal, indicating a possible vulnerability of the oyster immune system to electrophilic attack. New in vivo approaches were established, allowing the identification of higher rates of GSH–CDNB conjugate export to the seawater and enabling the measurement of the organic peroxide consumption rate. CDNB-induced impairment in antioxidant defenses decreased the peroxide removal rate from seawater. After showing that CDNB decreased gill antioxidant defenses and increased DNA damage in hemocytes, oysters were further challenged with 1 mM MEN over 24 h. MEN treatment did not affect thiol homeostasis in gills, while CDNB pre-treated animals recovered GSH and PSH to the control level after 24 h of depuration. Interestingly, MEN intensified GSH and PSH loss and mortality in CDNB-pre-treated animals, showing a clear synergistic effect. The superoxide-generating one-electron reduction of MEN was predominant in gills and may have contributed to MEN toxicity. These results support the idea that antioxidant-depleted animals are more susceptible to oxidative attack, which can compromise survival. Data also corroborate the idea that gills are an important detoxifying organ, able to dispose of organic peroxides, induce phase II enzymes, and efficiently export GSH

  18. Antioxidant deficit in gills of Pacific oyster (Crassostrea gigas) exposed to chlorodinitrobenzene increases menadione toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Trevisan, Rafael; Arl, Miriam [Departamento de Bioquimica, Universidade Federal de Santa Catarina, 88040-900 Florianopolis, SC (Brazil); Sacchet, Cassia Lopes [Universidade do Oeste do Estado de Santa Catarina, 89600-000 Joacaba, SC (Brazil); Engel, Cristiano Severino; Danielli, Naissa Maria; Mello, Danielle Ferraz [Departamento de Bioquimica, Universidade Federal de Santa Catarina, 88040-900 Florianopolis, SC (Brazil); Brocardo, Caroline [Universidade do Oeste do Estado de Santa Catarina, 89600-000 Joacaba, SC (Brazil); Maris, Angelica Francesca [Departamento de Biologia Celular, Embriologia e Genetica, Universidade Federal de Santa Catarina, 88040-900 Florianopolis, SC (Brazil); Dafre, Alcir Luiz, E-mail: alcir@ccb.ufsc.br [Departamento de Bioquimica, Universidade Federal de Santa Catarina, 88040-900 Florianopolis, SC (Brazil)

    2012-02-15

    Disturbances in antioxidant defenses decrease cellular protection against oxidative stress and jeopardize cellular homeostasis. To knock down the antioxidant defenses of Pacific oyster Crassostrea gigas, animals were pre-treated with 1-chloro-2,4-dinitrobenzene (CDNB) and further challenged with pro-oxidant menadione (MEN). CDNB pre-treatment (10 {mu}M for 18 h) was able to consume cellular thiols in gills, decreasing GSH (53%) and decrease protein thiols (25%). CDNB pre-treatment also disrupted glutathione reductase and thioredoxin reductase activity in the gills, but likewise strongly induced glutathione S-transferase activity (270% increase). Surprisingly, hemocyte viability was greatly affected 24 h after CDNB removal, indicating a possible vulnerability of the oyster immune system to electrophilic attack. New in vivo approaches were established, allowing the identification of higher rates of GSH-CDNB conjugate export to the seawater and enabling the measurement of the organic peroxide consumption rate. CDNB-induced impairment in antioxidant defenses decreased the peroxide removal rate from seawater. After showing that CDNB decreased gill antioxidant defenses and increased DNA damage in hemocytes, oysters were further challenged with 1 mM MEN over 24 h. MEN treatment did not affect thiol homeostasis in gills, while CDNB pre-treated animals recovered GSH and PSH to the control level after 24 h of depuration. Interestingly, MEN intensified GSH and PSH loss and mortality in CDNB-pre-treated animals, showing a clear synergistic effect. The superoxide-generating one-electron reduction of MEN was predominant in gills and may have contributed to MEN toxicity. These results support the idea that antioxidant-depleted animals are more susceptible to oxidative attack, which can compromise survival. Data also corroborate the idea that gills are an important detoxifying organ, able to dispose of organic peroxides, induce phase II enzymes, and efficiently export GSH

  19. 2-Bromo-1,4-naphthoquinone: a potentially improved substitute of menadione in Apatone™ therapy

    Directory of Open Access Journals (Sweden)

    F.S. Graciani

    2012-08-01

    Full Text Available Apatone™, a combination of menadione (2-methyl-1,4-naphthoquinone, VK3 and ascorbic acid (vitamin C, VC is a new strategy for cancer treatment. Part of its effect on tumor cells is related to the cellular pro-oxidative imbalance provoked by the generation of hydrogen peroxide (H2O2 through naphthoquinone redox cycling. In this study, we attempted to find new naphthoquinone derivatives that would increase the efficiency of H2O2 production, thereby potentially increasing its efficacy for cancer treatment. The presence of an electron-withdrawing group in the naphthoquinone moiety had a direct effect on the efficiency of H2O2 production. The compound 2-bromo-1,4-naphthoquinone (BrQ, in which the bromine atom substituted the methyl group in VK3, was approximately 10- and 19-fold more efficient than VK3 in terms of oxygen consumption and H2O2 production, respectively. The ratio [H2O2]produced / [naphthoquinone]consumed was 68 ± 11 and 5.8 ± 0.2 (µM/µM for BrQ and VK3, respectively, indicating a higher efficacy of BrQ as a catalyst for the autoxidation of ascorbic acid. Both VK3 and BrQ reacted with glutathione (GSH, but BrQ was the more effective substrate. Part of GSH was incorporated into the naphthoquinone, producing a nucleophilic substitution product (Q-SG. The depletion of BrQ by GSH did not prevent its redox capacity since Q-SG was also able to catalyze the production of reactive oxygen species. VK3/VC has already been submitted to clinical trials for the treatment of prostate cancer and has demonstrated promising results. However, replacement of VK3 with BrQ will open new lines of investigation regarding this approach to cancer treatment.

  20. 2-Bromo-1,4-naphthoquinone: a potentially improved substitute of menadione in Apatone™ therapy

    International Nuclear Information System (INIS)

    Graciani, F.S.; Ximenes, V.F.

    2012-01-01

    Apatone™, a combination of menadione (2-methyl-1,4-naphthoquinone, VK 3 ) and ascorbic acid (vitamin C, VC) is a new strategy for cancer treatment. Part of its effect on tumor cells is related to the cellular pro-oxidative imbalance provoked by the generation of hydrogen peroxide (H 2 O 2 ) through naphthoquinone redox cycling. In this study, we attempted to find new naphthoquinone derivatives that would increase the efficiency of H 2 O 2 production, thereby potentially increasing its efficacy for cancer treatment. The presence of an electron-withdrawing group in the naphthoquinone moiety had a direct effect on the efficiency of H 2 O 2 production. The compound 2-bromo-1,4-naphthoquinone (BrQ), in which the bromine atom substituted the methyl group in VK 3 , was approximately 10- and 19-fold more efficient than VK 3 in terms of oxygen consumption and H 2 O 2 production, respectively. The ratio [H 2 O 2 ] produced / [naphthoquinone] consumed was 68 ± 11 and 5.8 ± 0.2 (µM/µM) for BrQ and VK 3 , respectively, indicating a higher efficacy of BrQ as a catalyst for the autoxidation of ascorbic acid. Both VK 3 and BrQ reacted with glutathione (GSH), but BrQ was the more effective substrate. Part of GSH was incorporated into the naphthoquinone, producing a nucleophilic substitution product (Q-SG). The depletion of BrQ by GSH did not prevent its redox capacity since Q-SG was also able to catalyze the production of reactive oxygen species. VK 3 /VC has already been submitted to clinical trials for the treatment of prostate cancer and has demonstrated promising results. However, replacement of VK 3 with BrQ will open new lines of investigation regarding this approach to cancer treatment

  1. Absorption spectrometric and thermodynamic study of charge transfer complexes of menadione (Vitamin K3) with a series of phenols.

    Science.gov (United States)

    Pal, Purnendu; Bhattacharya, Sumanta; Mukherjee, Asok K; Mukherjee, Dulal C

    2005-03-01

    The electron donor-acceptor (EDA) interactions between menadione (i.e., 2-methyl-1,4-naphthoquinone, which is also called 'Vitamin K3') and a series of phenols (viz., phenol, resorcinol and p-quinol) have been studied in CCl4 medium. In all the cases, charge transfer (CT) bands have been located. The CT transition energies (h nu(CT)) of the complexes are found to change systematically with change in the number and position of the -OH groups in the aromatic ring of the phenol moiety. From the trends in the h nu(CT) values, the Hückel parameters (h(O) and k(C-O)) for the -OH group have been obtained. The CT transition energies are well correlated with the ionisation potentials of the phenols. From an analysis of this variation the electron affinity of Vitamin K3 has been found to be 2.28 eV. The stoichiometry of the complexes in each case has been found to be 1(menadione):2 (phenol). Formation constants of the complexes have been determined at four different temperatures from which the enthalpies and entropies of formation of the complexes have been estimated.

  2. Absorption spectrometric and thermodynamic study of charge transfer complexes of menadione (Vitamin K 3) with a series of phenols

    Science.gov (United States)

    Pal, Purnendu; Bhattacharya, Sumanta; Mukherjee, Asok K.; Mukherjee, Dulal C.

    2005-03-01

    The electron donor-acceptor (EDA) interactions between menadione (i.e., 2-methyl-1,4-naphthoquinone, which is also called 'Vitamin K 3') and a series of phenols (viz., phenol, resorcinol and p-quinol) have been studied in CCl 4 medium. In all the cases, charge transfer (CT) bands have been located. The CT transition energies ( hνCT) of the complexes are found to change systematically with change in the number and position of the -OH groups in the aromatic ring of the phenol moiety. From the trends in the hνCT values, the Hückel parameters ( hÖ and kC-Ö) for the -OH group have been obtained. The CT transition energies are well correlated with the ionisation potentials of the phenols. From an analysis of this variation the electron affinity of Vitamin K 3 has been found to be 2.28 eV. The stoichiometry of the complexes in each case has been found to be 1(menadione):2 (phenol). Formation constants of the complexes have been determined at four different temperatures from which the enthalpies and entropies of formation of the complexes have been estimated.

  3. Stress tolerances of nullmutants of function-unknown genes encoding menadione stress-responsive proteins in Aspergillus nidulans.

    Science.gov (United States)

    Leiter, Éva; Bálint, Mihály; Miskei, Márton; Orosz, Erzsébet; Szabó, Zsuzsa; Pócsi, István

    2016-07-01

    A group of menadione stress-responsive function-unkown genes of Aspergillus nidulans (Locus IDs ANID_03987.1, ANID_06058.1, ANID_10219.1, and ANID_10260.1) was deleted and phenotypically characterized. Importantly, comparative and phylogenetic analyses of the tested A. nidulans genes and their orthologs shed light only on the presence of a TANGO2 domain with NRDE protein motif in the translated ANID_06058.1 gene but did not reveal any recognizable protein-encoding domains in other protein sequences. The gene deletion strains were subjected to oxidative, osmotic, and metal ion stress and, surprisingly, only the ΔANID_10219.1 mutant showed an increased sensitivity to 0.12 mmol l(-1) menadione sodium bisulfite. The gene deletions affected the stress sensitivities (tolerances) irregularly, for example, some strains grew more slowly when exposed to various oxidants and/or osmotic stress generating agents, meanwhile the ΔANID_10260.1 mutant possessed a wild-type tolerance to all stressors tested. Our results are in line with earlier studies demonstrating that the deletions of stress-responsive genes do not confer necessarily any stress-sensitivity phenotypes, which can be attributed to compensatory mechanisms based on other elements of the stress response system with overlapping functions. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Disruption of mitochondrial function as mechanism for anti-cancer activity of a novel mitochondriotropic menadione derivative.

    Science.gov (United States)

    Teixeira, José; Amorim, Ricardo; Santos, Katia; Soares, Pedro; Datta, Sandipan; Cortopassi, Gino A; Serafim, Teresa L; Sardão, Vilma A; Garrido, Jorge; Borges, Fernanda; Oliveira, Paulo J

    2018-01-15

    Menadione, also known as vitamin K 3 , is a 2-methyl-1,4 naphthoquinone with a potent cytotoxic activity mainly resulting from its quinone redox-cycling with production of reactive oxygen species (ROS). Although increased ROS generation is considered a relevant mechanism in cancer cell death, it may not be sufficiently effective to kill cancer cells due to phenotypic adaptations. Therefore, combining ROS-generating agents with other molecules targeting important cancer cell phenotypes can be an effective therapeutic strategy. As mitochondrial dysfunction has been implicated in many human diseases, including cancer, we describe here the discovery of a mitochondrial-directed agent (MitoK 3 ), which was developed by conjugating a TPP cation to the C3 position of the menadione's naphthoquinone ring, increasing its selective accumulation in mitochondria, as well as led to alterations of its redox properties and consequent biological outcome. MitoK 3 disturbed the mitochondrial bioenergetic apparatus, with subsequent loss of mitochondrial ATP production. The combinatory strategy of MitoK 3 with anticancer agent doxorubicin (DOX) resulted in a degree of cytotoxicity higher than those of the individual molecules, as the combination triggered tumour apoptotic cell death evident by caspase 3/9 activities, probably through mitochondrial destabilization or by interference with mitochondrial redox processes. The results of this investigation support the importance of drug discovery process in developing molecules that can be use as adjuvant therapy in patients with specific cancer subtypes. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Validation of a stability-indicating hydrophilic interaction liquid chromatographic method for the quantitative determination of vitamin k3 (menadione sodium bisulfite) in injectable solution formulation.

    Science.gov (United States)

    Ghanem, Mashhour M; Abu-Lafi, Saleh A; Hallak, Hussein O

    2013-01-01

    A simple, specific, accurate, and stability-indicating method was developed and validated for the quantitative determination of menadione sodium bisulfite in the injectable solution formulation. The method is based on zwitterionic hydrophilic interaction liquid chromatography (ZIC-HILIC) coupled with a photodiode array detector. The desired separation was achieved on the ZIC-HILIC column (250 mm × 4.6 mm, 5 μm) at 25°C temperature. The optimized mobile phase consisted of an isocratic solvent mixture of 200mM ammonium acetate (NH4AC) solution and acetonitrile (ACN) (20:80; v/v) pH-adjusted to 5.7 by glacial acetic acid. The mobile phase was fixed at 0.5 ml/min and the analytes were monitored at 261 nm using a photodiode array detector. The effects of the chromatographic conditions on the peak retention, peak USP tailing factor, and column efficiency were systematically optimized. Forced degradation experiments were carried out by exposing menadione sodium bisulfite standard and the injectable solution formulation to thermal, photolytic, oxidative, and acid-base hydrolytic stress conditions. The degradation products were well-resolved from the main peak and the excipients, thus proving that the method is a reliable, stability-indicating tool. The method was validated as per ICH and USP guidelines (USP34/NF29) and found to be adequate for the routine quantitative estimation of menadione sodium bisulfite in commercially available menadione sodium bisulfite injectable solution dosage forms.

  6. Mononuclear nonheme iron(III) complexes that show superoxide dismutase-like activity and antioxidant effects against menadione-mediated oxidative stress.

    Science.gov (United States)

    Hitomi, Yutaka; Iwamoto, Yuji; Kashida, Akihiro; Kodera, Masahito

    2015-05-21

    This communication describes the superoxide dismutase (SOD)-like activity of mononuclear iron(III) complexes with pentadentate monocarboxylamido ligands. The SOD activity can be controlled by the electronic nature of the substituent group on the ligand. The nitro-substituted complex showed clear cytoprotective activity against menadione-mediated oxidative stress in cultured cells.

  7. Inhibition of the MRP1-mediated transport of the menadione-glutathione conjugate (thiodione) in HeLa cells as studied by SECM.

    Science.gov (United States)

    Koley, Dipankar; Bard, Allen J

    2012-07-17

    Oxidative stress induced in live HeLa cells by menadione (2-methyl-1,4-napthaquinone) was studied in real time by scanning electrochemical microscopy (SECM). The hydrophobic molecule menadione diffuses through a living cell membrane where it is toxic to the cell. However, in the cell it is conjugated with glutathione to form thiodione. Thiodione is then recognized and transported across the cell membrane via the ATP-driven MRP1 pump. In the extracellular environment, thiodione was detected by the SECM tip at levels of 140, 70, and 35 µM upon exposure of the cells to menadione concentrations of 500, 250, and 125 µM, respectively. With the aid of finite element modeling, the kinetics of thiodione transport was determined to be 1.6 10(-7) m/s, about 10 times faster than menadione uptake. Selective inhibition of these MRP1 pumps inside live HeLa cells by MK571 produced a lower thiodione concentration of 50 µM in presence of 500 µM menadione and 50 µM MK571. A similar reduced (50% drop) thiodione efflux was observed in the presence of monoclonal antibody QCRL-4, a selective blocking agent of the MRP1 pumps. The reduced thiodione flux confirmed that thiodione was transported by MRP1, and that glutathione is an essential substrate for MRP1-mediated transport. This finding demonstrates the usefulness of SECM in quantitative studies of MRP1 inhibitors and suggests that monoclonal antibodies can be a useful tool in inhibiting the transport of these MDR pumps, and thereby aiding in overcoming multidrug resistance.

  8. Real-time visualization of oxidative stress in a floating macrophyte Lemna minor L. exposed to cadmium, copper, menadione, and AAPH.

    Science.gov (United States)

    Razinger, Jaka; Drinovec, Luka; Zrimec, Alexis

    2010-12-01

    An ultra-sensitive digital imaging system was employed to visualize oxidative stress in intact L. minor plants exposed to Cd, Cu, menadione, AAPH, and ascorbate in real time. The increase of ROS production was assessed by measuring the rate of fluorescence intensity increases of the test medium supplemented with a fluorescing probe (dichlorofluorescein diacetate). The addition of 100 μM CdCl₂ or 100 μM CuSO₄ to the growth medium resulted in a significant increase of medium fluorescence. Additionally, CuSO₄ caused a significantly higher fluorescence intensity than CdCl₂ did. A strong positive correlation (R² = 0.99) between menadione concentration and fluorescence intensity was observed. The positive correlation between AAPH concentration and fluorescence intensity was not as strong as in the case of menadione (R² = 0.81). Menadione induced a stronger oxidative stress than similar concentration of AAPH. The addition of 100 μM ascorbate to L. minor treated with 50 μM menadione significantly reduced the fluorescence intensity increase. A linear trend of the fluorescence increase was observed in all treatments, indicating that chemical-induced oxidative stress is a gradual process and that the applied concentrations of the chemicals caused a constant increased production of ROS with different intensities, depending on the treatment. This is the combined result of a gradual diminishing of antioxidant reserves and accumulating oxidative damage. The observed rates of ROS production were slower than those in the studies using cell cultures. Copyright © 2009 Wiley Periodicals, Inc.

  9. Antiparasitic activity of menadione (vitamin K3) against Schistosoma mansoni in BABL/c mice.

    Science.gov (United States)

    Kapadia, Govind J; Soares, Ingrid A O; Rao, G Subba; Badoco, Fernanda R; Furtado, Ricardo A; Correa, Mariana B; Tavares, Denise C; Cunha, Wilson R; Magalhães, Lizandra G

    2017-03-01

    Schistosomiasis is one of the neglected tropical diseases affecting nearly quarter of a billion people in economically challenged tropical and subtropical countries of the world. Praziquantel (PZQ) is the only drug currently available to treat this parasitic disease in spite being ineffective against juvenile worms and concerns about developing resistance to treat reinfections. Our earlier in vitro viability studies demonstrated significant antiparasitic activity of menadione (MEN) (vitamin K 3 ) against Schistosoma mansoni adult worms. To gain insight into plausible mechanism of antischistosomal activity of MEN, its effect on superoxide anion levels in adult worms were studied in vitro which showed significant increases in both female and male worms. Further confirmation of the deleterious morphological changes in their teguments and organelles were obtained by ultrastructural analysis. Genotoxic and cytotoxic studies in male Swiss mice indicated that MEN was well tolerated at the oral dose of 500mg/kg using the criteria of MNPCE frequency and PCE/RBC ratio in the bone marrow of infected animals. The in vivo antiparasitic activity of MEN was conducted in female BALB/c mice infected with S. mansoni and significant reductions (P<0.001) in total worm burden were observed at single oral doses of 40 and 400mg/kg (48.57 and 61.90%, respectively). Additionally, MEN significantly reduced (P<0.001) the number of eggs in the liver of infected mice by 53.57 and 58.76%, respectively. Similarly, histological analysis of the livers showed a significant reduction (P<0.001) in the diameter of the granulomas. Since MEN is already in use globally as an over-the-counter drug for a variety of common ailments and a dietary supplement with a safety record in par with similar products when used in recommended doses, the above antiparasitic results which compare reasonably well with PZQ, make a compelling case for considering MEN to treat S. mansoni infection in humans. Copyright © 2016

  10. 2-Bromo-1,4-naphthoquinone: a potentially improved substitute of menadione in Apatone™ therapy

    Energy Technology Data Exchange (ETDEWEB)

    Graciani, F.S.; Ximenes, V.F. [Departamento de Química, Faculdade de Ciências, Universidade Estadual Paulista, Bauru SP (Brazil); Departamento de Análises Clínicas, Faculdade de Ciências Farmacêuticas, Universidade Estadual Paulista, Araraquara SP (Brazil)

    2012-05-18

    Apatone™, a combination of menadione (2-methyl-1,4-naphthoquinone, VK{sub 3}) and ascorbic acid (vitamin C, VC) is a new strategy for cancer treatment. Part of its effect on tumor cells is related to the cellular pro-oxidative imbalance provoked by the generation of hydrogen peroxide (H{sub 2}O{sub 2}) through naphthoquinone redox cycling. In this study, we attempted to find new naphthoquinone derivatives that would increase the efficiency of H{sub 2}O{sub 2} production, thereby potentially increasing its efficacy for cancer treatment. The presence of an electron-withdrawing group in the naphthoquinone moiety had a direct effect on the efficiency of H{sub 2}O{sub 2} production. The compound 2-bromo-1,4-naphthoquinone (BrQ), in which the bromine atom substituted the methyl group in VK{sub 3}, was approximately 10- and 19-fold more efficient than VK{sub 3} in terms of oxygen consumption and H{sub 2}O{sub 2} production, respectively. The ratio [H{sub 2}O{sub 2}]{sub produced} / [naphthoquinone]{sub consumed} was 68 ± 11 and 5.8 ± 0.2 (µM/µM) for BrQ and VK{sub 3}, respectively, indicating a higher efficacy of BrQ as a catalyst for the autoxidation of ascorbic acid. Both VK{sub 3} and BrQ reacted with glutathione (GSH), but BrQ was the more effective substrate. Part of GSH was incorporated into the naphthoquinone, producing a nucleophilic substitution product (Q-SG). The depletion of BrQ by GSH did not prevent its redox capacity since Q-SG was also able to catalyze the production of reactive oxygen species. VK{sub 3}/VC has already been submitted to clinical trials for the treatment of prostate cancer and has demonstrated promising results. However, replacement of VK{sub 3} with BrQ will open new lines of investigation regarding this approach to cancer treatment.

  11. Decarbonylated cyclophilin A Cpr1 protein protects Saccharomyces cerevisiae KNU5377Y when exposed to stress induced by menadione.

    Science.gov (United States)

    Kim, Il-Sup; Jin, Ingnyol; Yoon, Ho-Sung

    2011-01-01

    Cyclophilins are conserved cis-trans peptidyl-prolyl isomerase that are implicated in protein folding and function as molecular chaperones. The accumulation of Cpr1 protein to menadione in Saccharomyces cerevisiae KNU5377Y suggests a possibility that this protein may participate in the mechanism of stress tolerance. Stress response of S. cerevisiae KNU5377Y cpr1Δ mutant strain was investigated in the presence of menadione (MD). The growth ability of the strain was confirmed in an oxidant-supplemented medium, and a relationship was established between diminishing levels of cell rescue enzymes and MD sensitivity. The results demonstrate the significant effect of CPR1 disruption in the cellular growth rate, cell viability and morphology, and redox state in the presence of MD and suggest the possible role of Cpr1p in acquiring sensitivity to MD and its physiological role in cellular stress tolerance. The in vivo importance of Cpr1p for antioxidant-mediated reactive oxygen species (ROS) neutralization and chaperone-mediated protein folding was confirmed by analyzing the expression changes of a variety of cell rescue proteins in a CPR1-disrupted strain. The cpr1Δ to the exogenous MD showed reduced expression level of antioxidant enzymes, molecular chaperones, and metabolic enzymes such as nicotinamide adenine dinucleotide phosphate (NADPH)- or adenosine triphosphate (ATP)-generating systems. More importantly, it was shown that cpr1Δ mutant caused imbalance in the cellular redox homeostasis and increased ROS levels in the cytosol as well as mitochondria and elevated iron concentrations. As a result of excess ROS production, the cpr1Δ mutant provoked an increase in oxidative damage and a reduction in antioxidant activity and free radical scavenger ability. However, there was no difference in the stress responses between the wild-type and the cpr1Δ mutant strains derived from S. cerevisiae BY4741 as a control strain under the same stress. Unlike BY4741, KNU5377Y Cpr1

  12. Menadione (Vitamin K3) induces apoptosis of human oral cancer cells and reduces their metastatic potential by modulating the expression of epithelial to mesenchymal transition markers and inhibiting migration.

    Science.gov (United States)

    Suresh, Shruthy; Raghu, Dinesh; Karunagaran, Devarajan

    2013-01-01

    Oral cancer is one of the most commonly occurring cancers worldwide, decreasing the patient's survival rate due to tumor recurrence and metastasis. Menadione (Vitamin K3) is known to exhibit cytotoxicity in various cancer cells but the present study focused on its effects on viability, apoptosis, epithelial to mesenchymal transition (EMT), anchorage independent growth and migration of oral cancer cells. The results show that menadione is more cytotoxic to SAS (oral squamous carcinoma) cells but not to non-tumorigenic HEK293 and HaCaT cells. Menadione treatment increased the expression of pro-apoptotic proteins, Bax and p53, with a concurrent decrease in anti-apoptotic proteins, Bcl-2 and p65. Menadione induced the expression of E-cadherin but reduced the expression of EMT markers, vimentin and fibronectin. Menadione also inhibited anchorage independent growth and migration in SAS cells. These findings reveal and confirm that menadione is a potential candidate in oral cancer therapy as it exhibits cytotoxic, antineoplastic and antimigratory effects besides effectively blocking EMT in oral cancer cells.

  13. Menadione-Induced Oxidative Stress Re-Shapes the Oxylipin Profile of Aspergillus flavus and Its Lifestyle

    Science.gov (United States)

    Zaccaria, Marco; Ludovici, Matteo; Sanzani, Simona Marianna; Ippolito, Antonio; Aiese Cigliano, Riccardo; Sanseverino, Walter; Scarpari, Marzia; Scala, Valeria; Fanelli, Corrado; Reverberi, Massimo

    2015-01-01

    Aspergillus flavus is an efficient producer of mycotoxins, particularly aflatoxin B1, probably the most hepatocarcinogenic naturally-occurring compound. Although the inducing agents of toxin synthesis are not unanimously identified, there is evidence that oxidative stress is one of the main actors in play. In our study, we use menadione, a quinone extensively implemented in studies on ROS response in animal cells, for causing stress to A. flavus. For uncovering the molecular determinants that drive A. flavus in challenging oxidative stress conditions, we have evaluated a wide spectrum of several different parameters, ranging from metabolic (ROS and oxylipin profile) to transcriptional analysis (RNA-seq). There emerges a scenario in which A. flavus activates several metabolic processes under oxidative stress conditions for limiting the ROS-associated detrimental effects, as well as for triggering adaptive and escape strategies. PMID:26512693

  14. Menadione-Induced Oxidative Stress Re-Shapes the Oxylipin Profile of Aspergillus flavus and Its Lifestyle

    Directory of Open Access Journals (Sweden)

    Marco Zaccaria

    2015-10-01

    Full Text Available Aspergillus flavus is an efficient producer of mycotoxins, particularly aflatoxin B1, probably the most hepatocarcinogenic naturally-occurring compound. Although the inducing agents of toxin synthesis are not unanimously identified, there is evidence that oxidative stress is one of the main actors in play. In our study, we use menadione, a quinone extensively implemented in studies on ROS response in animal cells, for causing stress to A. flavus. For uncovering the molecular determinants that drive A. flavus in challenging oxidative stress conditions, we have evaluated a wide spectrum of several different parameters, ranging from metabolic (ROS and oxylipin profile to transcriptional analysis (RNA-seq. There emerges a scenario in which A. flavus activates several metabolic processes under oxidative stress conditions for limiting the ROS-associated detrimental effects, as well as for triggering adaptive and escape strategies.

  15. Menadione-Induced Oxidative Stress Re-Shapes the Oxylipin Profile of Aspergillus flavus and Its Lifestyle.

    Science.gov (United States)

    Zaccaria, Marco; Ludovici, Matteo; Sanzani, Simona Marianna; Ippolito, Antonio; Cigliano, Riccardo Aiese; Sanseverino, Walter; Scarpari, Marzia; Scala, Valeria; Fanelli, Corrado; Reverberi, Massimo

    2015-10-23

    Aspergillus flavus is an efficient producer of mycotoxins, particularly aflatoxin B₁, probably the most hepatocarcinogenic naturally-occurring compound. Although the inducing agents of toxin synthesis are not unanimously identified, there is evidence that oxidative stress is one of the main actors in play. In our study, we use menadione, a quinone extensively implemented in studies on ROS response in animal cells, for causing stress to A. flavus. For uncovering the molecular determinants that drive A. flavus in challenging oxidative stress conditions, we have evaluated a wide spectrum of several different parameters, ranging from metabolic (ROS and oxylipin profile) to transcriptional analysis (RNA-seq). There emerges a scenario in which A. flavus activates several metabolic processes under oxidative stress conditions for limiting the ROS-associated detrimental effects, as well as for triggering adaptive and escape strategies.

  16. Protection by the flavonoids quercetin and luteolin against peroxide- or menadione-induced oxidative stress in MC3T3-E1 osteoblast cells.

    Science.gov (United States)

    Fatokun, Amos A; Tome, Mercedes; Smith, Robert A; Darlington, L Gail; Stone, Trevor W

    2015-01-01

    Potential protective effects of the flavonoids quercetin and luteolin have been examined against the oxidative stress of MC3T3-E1 osteoblast-like cells. Although hydrogen peroxide and menadione reduced cell viability, the toxicity was prevented by desferrioxamine or catalase but not superoxide dismutase, suggesting the involvement of hydrogen peroxide in both cases. Quercetin and luteolin reduced the oxidative damage, especially that caused by hydrogen peroxide. When cultures were pre-incubated with quercetin or luteolin, protection was reduced or lost. Protection was also reduced when a 24 h pre-incubation with the flavonoids was followed by exposure to menadione alone. Pretreating cultures with luteolin impaired protection by quercetin, whereas quercetin pretreatment did not affect protection by luteolin. It is concluded that quercetin and luteolin suppress oxidative damage to MC3T3-E1 cells, especially caused by peroxide. The reduction in protection by pretreatment implies a down-regulation of part of the toxic transduction pathway.

  17. Administration of Menadione, Vitamin K3, Ameliorates Off-Target Effects on Corneal Epithelial Wound Healing Due to Receptor Tyrosine Kinase Inhibition.

    Science.gov (United States)

    Rush, Jamie S; Bingaman, David P; Chaney, Paul G; Wax, Martin B; Ceresa, Brian P

    2016-11-01

    The antiangiogenic receptor tyrosine kinase inhibitor (RTKi), 3-[(4-bromo-2,6-difluorophenyl)methoxy]-5-[[[[4-(1-pyrrolidinyl) butyl] amino] carbonyl]amino]-4-isothiazolecarboxamide hydrochloride, targets VEGFR2 (half maximal inhibitory concentration [IC50] = 11 nM); however, off-target inhibition of epidermal growth factor receptor (EGFR) occurs at higher concentrations. (IC50 = 5.8 μM). This study was designed to determine the effect of topical RTKi treatment on EGF-mediated corneal epithelial wound healing and to develop new strategies to minimize off-target EGFR inhibition. In vitro corneal epithelial wound healing was measured in response to EGF using a transformed human cell line (hTCEpi cells). In vivo corneal wound healing was assessed using a murine model. In these complementary assays, wound healing was measured in the presence of varying RTKi concentrations. Immunoblot analysis was used to examine EGFR and VEGFR2 phosphorylation and the kinetics of EGFR degradation. An Alamar Blue assay measured VEGFR2-mediated cell biology. Receptor tyrosine kinase inhibitor exposure caused dose-dependent inhibition of EGFR-mediated corneal epithelial wound healing in vitro and in vivo. Nanomolar concentrations of menadione, a vitamin K3 analog, when coadministered with the RTKi, slowed EGFR degradation and ameliorated the inhibitory effects on epithelial wound healing both in vitro and in vivo. Menadione did not alter the RTKi's IC50 against VEGFR2 phosphorylation or its inhibition of VEGF-induced retinal endothelial cell proliferation. An antiangiogenic RTKi exhibited off-target effects on the corneal epithelium that can be minimized by menadione without deleteriously affecting its on-target VEGFR2 blockade. These data indicate that menadione has potential as a topical supplement for individuals suffering from perturbations in corneal epithelial homeostasis, especially as an untoward side effect of kinase inhibitors.

  18. Prostaglandin E2 blocks menadione-induced apoptosis through the Ras/Raf/Erk signaling pathway in promonocytic leukemia cell lines.

    Science.gov (United States)

    Yeo, Hyun-Seok; Shehzad, Adeeb; Lee, Young Sup

    2012-04-01

    Altered oxidative stress has long been observed in cancer cells, and this biochemical property of cancer cells represents a specific vulnerability that can be exploited for therapeutic benefit. The major role of an elevated oxidative stress for the efficacy of molecular targeted drugs is under investigation. Menadione is considered an attractive model for the study of oxidative stress, which can induce apoptosis in human leukemia HL-60 cell lines. Prostaglandin E(2) (PGE(2)) via its receptors not only promotes cell survival but also reverses apoptosis and promotes cancer progression. Here, we present evidence for the biological role of PGE(2) as a protective agent of oxidative stress-induced apoptosis in monocytic cells. Pretreatment of HL-60 cells with PGE(2) markedly ameliorated the menadione-induced apoptosis and inhibited the degradation of PARP and lamin B. The EP(2) receptor antagonist AH6809 abrogated the inhibitory effect of PGE(2), suggesting the role of the EP(2)/cAMP system. The PKA inhibitor H89 also reversed apoptosis and decreased the PKA activity that was elevated 10-fold by PGE(2). The treatment of HL-60 cells with NAC or zinc chloride showed a similar protective effect as with PGE(2) on menadione-treated cells. Furthermore, PGE(2) activated the Ras/Raf/MEK pathway, which in turn initiated ERK activation, and ultimately protected menadione-induced apoptosis. These results imply that PGE(2) via cell survival pathways may protect oxidative stress-induced apoptosis in monocytic cells. This study warrants further pre-clinical investigation as well as application towards leukemia clinics.

  19. Synthesis of isochromene-type scaffolds via single-flask Diels-Alder-[4 + 2]-annulation sequence of a silyl-substituted diene with menadione.

    Science.gov (United States)

    Lee, Jihoon; Panek, James S

    2014-06-20

    A sequential Diels-Alder reaction/silicon-directed [4 + 2]-annulation was developed to assemble hydroisochromene-type ring systems from menadione 2. In the first step, a Diels-Alder of the 1-silyl-substituted butadiene 1 with 2 furnished an intermediate cyclic allylsilane. Subsequently, TMSOTf promoted a [4 + 2]-annulation through trapping of an oxonium, generated by condensation between an aldehyde and the TBS protected alcohol resulted in the formation of a cis-fused hydroisochromene 13.

  20. Menadione (Vitamin K3) Is a Catabolic Product of Oral Phylloquinone (Vitamin K1) in the Intestine and a Circulating Precursor of Tissue Menaquinone-4 (Vitamin K2) in Rats*

    Science.gov (United States)

    Hirota, Yoshihisa; Tsugawa, Naoko; Nakagawa, Kimie; Suhara, Yoshitomo; Tanaka, Kiyoshi; Uchino, Yuri; Takeuchi, Atsuko; Sawada, Natsumi; Kamao, Maya; Wada, Akimori; Okitsu, Takashi; Okano, Toshio

    2013-01-01

    Mice have the ability to convert dietary phylloquinone (vitamin K1) into menaquinone-4 (vitamin K2) and store the latter in tissues. A prenyltransferase enzyme, UbiA prenyltransferase domain-containing 1 (UBIAD1), is involved in this conversion. There is evidence that UBIAD1 has a weak side chain cleavage activity for phylloquinone but a strong prenylation activity for menadione (vitamin K3), which has long been postulated as an intermediate in this conversion. Further evidence indicates that when intravenously administered in mice phylloquinone can enter into tissues but is not converted further to menaquinone-4. These findings raise the question whether phylloquinone is absorbed and delivered to tissues in its original form and converted to menaquinone-4 or whether it is converted to menadione in the intestine followed by delivery of menadione to tissues and subsequent conversion to menaquinone-4. To answer this question, we conducted cannulation experiments using stable isotope tracer technology in rats. We confirmed that the second pathway is correct on the basis of structural assignments and measurements of phylloquinone-derived menadione using high resolution MS analysis and a bioassay using recombinant UBIAD1 protein. Furthermore, high resolution MS and 1H NMR analyses of the product generated from the incubation of menadione with recombinant UBIAD1 revealed that the hydroquinone, but not the quinone form of menadione, was an intermediate of the conversion. Taken together, these results provide unequivocal evidence that menadione is a catabolic product of oral phylloquinone and a major source of tissue menaquinone-4. PMID:24085302

  1. Molecular insights into human monoamine oxidase (MAO) inhibition by 1,4-naphthoquinone: evidences for menadione (vitamin K3) acting as a competitive and reversible inhibitor of MAO.

    Science.gov (United States)

    Coelho Cerqueira, Eduardo; Netz, Paulo Augusto; Diniz, Cristiane; Petry do Canto, Vanessa; Follmer, Cristian

    2011-12-15

    Monoamine oxidase (MAO) catalyzes the oxidative deamination of biogenic and exogenous amines and its inhibitors have therapeutic value for several conditions including affective disorders, stroke, neurodegenerative diseases and aging. The discovery of 2,3,6-trimethyl-1,4-naphthoquinone (TMN) as a nonselective and reversible inhibitor of MAO, has suggested 1,4-naphthoquinone (1,4-NQ) as a potential scaffold for designing new MAO inhibitors. Combining molecular modeling tools and biochemical assays we evaluate the kinetic and molecular details of the inhibition of human MAO by 1,4-NQ, comparing it with TMN and menadione. Menadione (2-methyl-1,4-naphthoquinone) is a multitarget drug that acts as a precursor of vitamin K and an inducer of mitochondrial permeability transition. Herein we show that MAO-B was inhibited competitively by 1,4-NQ (K(i)=1.4 μM) whereas MAO-A was inhibited by non-competitive mechanism (K(i)=7.7 μM). Contrasting with TMN and 1,4-NQ, menadione exhibited a 60-fold selectivity for MAO-B (K(i)=0.4 μM) in comparison with MAO-A (K(i)=26 μM), which makes it as selective as rasagiline. Fluorescence and molecular modeling data indicated that these inhibitors interact with the flavin moiety at the active site of the enzyme. Additionally, docking studies suggest the phenyl side groups of Tyr407 and Tyr444 (for MAO-A) or Tyr398 and Tyr435 (for MAO-B) play an important role in the interaction of the enzyme with 1,4-NQ scaffold through forces of dispersion as verified for menadione, TMN and 1,4-NQ. Taken together, our findings reveal the molecular details of MAO inhibition by 1,4-NQ scaffold and show for the first time that menadione acts as a competitive and reversible inhibitor of human MAO. Copyright © 2011 Elsevier Ltd. All rights reserved.

  2. A Suppressor of the Menadione-Hypersensitive Phenotype of a Xanthomonas campestris pv. phaseoli oxyR Mutant Reveals a Novel Mechanism of Toxicity and the Protective Role of Alkyl Hydroperoxide Reductase

    Science.gov (United States)

    Vattanaviboon, Paiboon; Whangsuk, Wirongrong; Mongkolsuk, Skorn

    2003-01-01

    We isolated menadione-resistant mutants of Xanthomonas campestris pv. phaseoli oxyR (oxyRXp). The oxyRR2Xp mutant was hyperresistant to the superoxide generators menadione and plumbagin and was moderately resistant to H2O2 and tert-butyl hydroperoxide. Analysis of enzymes involved in oxidative-stress protection in the oxyRR2Xp mutant revealed a >10-fold increase in AhpC and AhpF levels, while the levels of superoxide dismutase (SOD), catalase, and the organic hydroperoxide resistance protein (Ohr) were not significantly altered. Inactivation of ahpC in the oxyRR2Xp mutant resulted in increased sensitivity to menadione killing. Moreover, high levels of expression of cloned ahpC and ahpF in the oxyRXp mutant complemented the menadione hypersensitivity phenotype. High levels of other oxidant-scavenging enzymes such as catalase and SOD did not protect the cells from menadione toxicity. These data strongly suggest that the toxicity of superoxide generators could be mediated via organic peroxide production and that alkyl hydroperoxide reductase has an important novel function in the protection against the toxicity of these compounds in X. campestris. PMID:12591894

  3. Inhibition of Siah2 ubiquitin ligase by vitamin K3 (menadione) attenuates hypoxia and MAPK signaling and blocks melanoma tumorigenesis.

    Science.gov (United States)

    Shah, Meera; Stebbins, John L; Dewing, Antimone; Qi, Jianfei; Pellecchia, Maurizio; Ronai, Ze'ev A

    2009-12-01

    The E3 ubiquitin ligase Siah2 has been implicated in the regulation of the hypoxia response, as well as in the control of Ras, JNK/p38/NF-kappaB signaling pathways. Both Ras/mitogen-activated protein kinase (MAPK) and hypoxia pathways are important for melanoma development and progression, pointing to the possible use of Siah2 as target for treatment of this tumor type. In the present study, we have established a high-throughput electro-chemiluninescent-based assay in order to screen and identify inhibitors of Siah2 ubiquitin ligase activity. Of 1840 compounds screened, we identified and characterized menadione (MEN) as a specific inhibitor of Siah2 ligase activity. MEN attenuated Siah2 self-ubiquitination, and increased expression of its substrates PHD3 and Sprouty2, with concomitant decrease in levels of HIF-1alpha and pERK, the respective downstream effectors. MEN treatment no longer affected PHD3 or Sprouty2 in Siah-KO cells, pointing to its Siah-dependent effects. Further, MEN inhibition of Siah2 was not attenuated by free radical scavenger, suggesting it is ROS-independent. Significantly, growth of xenograft melanoma tumors was inhibited following the administration of MEN or its derivative. These findings reveal an efficient platform for the identification of Siah inhibitors while identifying and characterizing MEN as Siah inhibitor that attenuates hypoxia and MAPK signaling, and inhibits melanoma tumorigenesis.

  4. Inhibition of Siah2 ubiquitin ligase by vitamin K3 (menadione) attenuates hypoxia and MAPK signaling and blocks melanoma tumorigenesis

    Science.gov (United States)

    Shah, Meera; Stebbins, John L.; Dewing, Antimone; Qi, Jianfei; Pellecchia, Maurizio; Ronai, Ze’ev A.

    2010-01-01

    Summary The E3 ubiquitin ligase Siah2 has been implicated in the regulation of the hypoxia response, as well as in the control of Ras, JNK/p38/NF-κB signaling pathways. Both Ras/mitogen-activated protein kinase (MAPK) and hypoxia pathways are important for melanoma development and progression, pointing to the possible use of Siah2 as target for treatment of this tumor type. In the present study, we have established a high-throughput electro-chemiluninescent-based assay in order to screen and identify inhibitors of Siah2 ubiquitin ligase activity. Of 1840 compounds screened, we identified and characterized menadione (MEN) as a specific inhibitor of Siah2 ligase activity. MEN attenuated Siah2 self-ubiquitination, and increased expression of its substrates PHD3 and Sprouty2, with concomitant decrease in levels of HIF-1α and pERK, the respective downstream effectors. MEN treatment no longer affected PHD3 or Sprouty2 in Siah-KO cells, pointing to its Siah-dependent effects. Further, MEN inhibition of Siah2 was not attenuated by free radical scavenger, suggesting it is ROS-independent. Significantly, growth of xenograft melanoma tumors was inhibited following the administration of MEN or its derivative. These findings reveal an efficient platform for the identification of Siah inhibitors while identifying and characterizing MEN as Siah inhibitor that attenuates hypoxia and MAPK signaling, and inhibits melanoma tumorigenesis. PMID:19712206

  5. Effective stimulation of the biotechnological potential of the medicinal white rot fungus: Phellinus pini by menadione-mediated oxidative stress.

    Science.gov (United States)

    Jaszek, Magdalena; Kos, Katarzyna; Matuszewska, Anna; Grąz, Marcin; Stefaniuk, Dawid; Osińska-Jaroszuk, Monika; Prendecka, Monika; Jóźwik, Ewa; Grzywnowicz, Krzysztof

    2014-09-01

    The effect of menadione (MQ; 2-methyl-1,4-naphtoquinone), a superoxide-generating agent, on the natural biodegradation system in the medicinal white rot fungus Phellinus pini was determined. While measuring the activities of extracellular manganese-dependent peroxidase (MnP) and intracellular chitinase, it was found that the application of MQ (0.75 mM) distinctly stimulated the activities of these enzymes in comparison to the control values (without MQ). Using the capillary electrophoresis (CE) method, an increase in the extracellular oxalic acid (OXA) concentration was detected during the first days after the addition of MQ. It was observed that the rate of intracellular proteolysis at pH 3.5 evidently decreased under oxidative stress conditions. Contrary to these results, the activities of serine proteases at pH 9.5 measured against fluorogenic peptide substrates distinctly increased in stressed cultures. The MQ treatment also caused an evident increase in the catalase (CAT) activity, as well as the levels of superoxide anion radicals (SORs), formaldehyde (FA), and phenolic compounds (PHC) in the experimental cultures. The results obtained confirm that prooxidants may find application as an effective way to stimulate biotechnological production of MnP and chitinase by white rot fungi.

  6. Modulation of notch signaling pathway to prevent H2O2/menadione-induced SK-N-MC cells death by EUK134.

    Science.gov (United States)

    Kamarehei, Maryam; Yazdanparast, Razieh

    2014-10-01

    The brain in Alzheimer's disease is under increased oxidative stress, and this may have a role in the pathogenesis and neural death in this disorder. It has been verified that numerous signaling pathways involved in neurodegenerative disorders are activated in response to reactive oxygen species (ROS). EUK134, a synthetic salen-manganese antioxidant complex, has been found to possess many interesting pharmacological activities awaiting exploration. The present study is to characterize the role of Notch signaling in apoptotic cell death of SK-N-MC cells. The cells were treated with hydrogen peroxide (H2O2) or menadione to induce oxidative stress. The free-radical scavenging capabilities of EUK134 were studied through the MTT assay, glutathione peroxidase (GPx) enzyme activity assay, and glutathione (GSH) Levels. The extents of lipid peroxidation, protein carbonyl formation, and intracellular ROS levels, as markers of oxidative stress, were also studied. Our results showed that H2O2/menadione reduced GSH levels and GPx activity. However, EUK134 protected cells against ROS-induced cell death by down-regulation of lipid peroxidation and protein carbonyl formation as well as restoration of antioxidant enzymes activity. ROS induced apoptosis and increased NICD and HES1 expression. Inhibition of NICD production proved that Notch signaling is involved in apoptosis through p53 activation. Moreover, H2O2/menadione led to Numb protein down-regulation which upon EUK134 pretreatment, its level increased and subsequently prevented Notch pathway activation. We indicated that EUK134 can be a promising candidate in designing natural-based drugs for ROS-induced neurodegenerative diseases. Collectively, ROS activated Notch signaling in SK-N-MC cells leading to cell apoptosis.

  7. Vitamin K3 (menadione)-induced oncosis associated with keratin 8 phosphorylation and histone H3 arylation.

    Science.gov (United States)

    Scott, Gary K; Atsriku, Christian; Kaminker, Patrick; Held, Jason; Gibson, Brad; Baldwin, Michael A; Benz, Christopher C

    2005-09-01

    The vitamin K analog menadione (K3), capable of both redox cycling and arylating nucleophilic substrates by Michael addition, has been extensively studied as a model stress-inducing quinone in both cell culture and animal model systems. Exposure of keratin 8 (k-8) expressing human breast cancer cells (MCF7, T47D, SKBr3) to K3 (50-100 microM) induced rapid, sustained, and site-specific k-8 serine phosphorylation (pSer73) dependent on signaling by a single mitogen activated protein kinase (MAPK) pathway, MEK1/2. Normal nuclear morphology and k-8 immunofluorescence coupled with the lack of DNA laddering or other features of apoptosis indicated that K3-induced cytotoxicity, evident within 4 h of treatment and delayed but not prevented by MEK1/2 inhibition, was due to a form of stress-activated cell death known as oncosis. Independent of MAPK signaling was the progressive appearance of K3-induced cellular fluorescence, principally nuclear in origin and suggested by in vitro fluorimetry to have been caused by K3 thiol arylation. Imaging by UV transillumination of protein gels containing nuclear extracts from K3-treated cells revealed a prominent 17-kDa band shown to be histone H3 by immunoblotting and mass spectrometry (MS). K3 arylation of histones in vitro followed by electrospray ionization-tandem MS analyses identified the unique Cys110 residue within H3, exposed only in the open chromatin of transcriptionally active genes, as a K3 arylation target. These findings delineate new pathways associated with K3-induced stress and suggest a potentially novel role for H3 Cys110 as a nuclear stress sensor.

  8. Menadione-Induced DNA Damage Leads to Mitochondrial Dysfunction and Fragmentation During Rosette Formation in Fuchs Endothelial Corneal Dystrophy.

    Science.gov (United States)

    Halilovic, Adna; Schmedt, Thore; Benischke, Anne-Sophie; Hamill, Cecily; Chen, Yuming; Santos, Janine Hertzog; Jurkunas, Ula V

    2016-06-20

    Fuchs endothelial corneal dystrophy (FECD), a leading cause of age-related corneal edema requiring transplantation, is characterized by rosette formation of corneal endothelium with ensuing apoptosis. We sought to determine whether excess of mitochondrial reactive oxygen species leads to chronic accumulation of oxidative DNA damage and mitochondrial dysfunction, instigating cell death. We modeled the pathognomonic rosette formation of postmitotic corneal cells by increasing endogenous cellular oxidative stress with menadione (MN) and performed a temporal analysis of its effect in normal (HCEnC, HCECi) and FECD (FECDi) cells and ex vivo specimens. FECDi and FECD ex vivo specimens exhibited extensive mtDNA and nDNA damage as detected by quantitative PCR. Exposure to MN triggered an increase in mitochondrial superoxide levels and led to mtDNA and nDNA damage, while DNA amplification was restored with NAC pretreatment. Furthermore, MN exposure led to a decrease in ΔΨm and adenosine triphosphate levels in normal cells, while FECDi exhibited mitochondrial dysfunction at baseline. Mitochondrial fragmentation and cytochrome c release were detected in FECD tissue and after MN treatment of HCEnCs. Furthermore, cleavage of caspase-9 and caspase-3 followed MN-induced cytochrome c release in HCEnCs. This study provides the first line of evidence that accumulation of oxidative DNA damage leads to rosette formation, loss of functionally intact mitochondria via fragmentation, and subsequent cell death during postmitotic cell degeneration of ocular tissue. MN induced rosette formation, along with mtDNA and nDNA damage, mitochondrial dysfunction, and fragmentation, leading to activation of the intrinsic apoptosis via caspase cleavage and cytochrome c release. Antioxid. Redox Signal. 24, 1072-1083.

  9. A novel liquid chromatography-tandem mass spectrometry method for determination of menadione in human plasma after derivatization with 3-mercaptopropionic acid.

    Science.gov (United States)

    Liu, Ruijuan; Wang, Mengmeng; Ding, Li

    2014-10-01

    Menadione (VK3), an essential fat-soluble naphthoquinone, takes very important physiological and pathological roles, but its detection and quantification is challenging. Herein, a new method was developed for quantification of VK3 in human plasma by liquid chromatography-tandem mass spectrometry (LC-MS/MS) after derivatization with 3-mercaptopropionic acid via Michael addition reaction. The derivative had been identified by the mass spectra and the derivatization conditions were optimized by considering different parameters. The method was demonstrated with high sensitivity and a low limit of quantification of 0.03 ng mL(-1) for VK3, which is about 33-fold better than that for the direct analysis of the underivatized compound. The method also had good precision and reproducibility. It was applied in the determination of basal VK3 in human plasma and a clinical pharmacokinetic study of menadiol sodium diphosphate. Furthermore, the method for the quantification of VK3 using LC-MS/MS was reported in this paper for the first time, and it will provide an important strategy for the further research on VK3 and menadione analogs. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Superoxide dismutases and glutaredoxins have a distinct role in the response of Candida albicans to oxidative stress generated by the chemical compounds menadione and diamide.

    Science.gov (United States)

    Chaves, Guilherme Maranhão; da Silva, Walicyranison Plinio

    2012-12-01

    To cope with oxidative stress, Candida albicans possesses several enzymes involved in a number of biological processes, including superoxide dismutases (Sods) and glutaredoxins (Grxs). The resistance of C. albicans to reactive oxygen species is thought to act as a virulence factor. Genes such as SOD1 and GRX2, which encode for a Sod and Grx, respectively, in C. albicans are widely recognised to be important for pathogenesis. We generated a double mutant, Δgrx2/sod1, for both genes. This strain is very defective in hyphae formation and is susceptible to killing by neutrophils. When exposed to two compounds that generate reactive oxygen species, the double null mutant was susceptible to menadione and resistant to diamide. The reintegration of the SOD1 gene in the null mutant led to recovery in resistance to menadione, whereas reintegration of the GRX2 gene made the null mutant sensitive to diamide. Despite having two different roles in the responses to oxidative stress generated by chemical compounds, GRX2 and SOD1 are important for C. albicans pathogenesis because the double mutant Δgrx2/sod1 was very susceptible to neutrophil killing and was defective in hyphae formation in addition to having a lower virulence in an animal model of systemic infection.

  11. On methods for the detection of reactive oxygen species generation by human spermatozoa: analysis of the cellular responses to catechol oestrogen, lipid aldehyde, menadione and arachidonic acid.

    Science.gov (United States)

    Aitken, R J; Smith, T B; Lord, T; Kuczera, L; Koppers, A J; Naumovski, N; Connaughton, H; Baker, M A; De Iuliis, G N

    2013-03-01

    Oxidative stress is known to have a major impact on human sperm function and, as a result, there is a need to develop sensitive methods for measuring reactive oxygen species (ROS) generation by these cells. A variety of techniques have been developed for this purpose including chemiluminescence (luminol and lucigenin), flow cytometry (MitoSOX Red, dihydroethidium, 4,5-diaminofluorescein diacetate and 2',7'-dichlorodihydrofluorescein diacetate) and spectrophotometry (nitroblue tetrazolium). The relative sensitivity of these assays and their comparative ability to detect ROS generated in different subcellular compartments of human spermatozoa, have not previously been investigated. To address this issue, we have compared the performance of these assays when ROS generation was triggered with a variety of reagents including 2-hydroxyestradiol, menadione, 4-hydroxynonenal and arachidonic acid. The results revealed that menadione predominantly induced release of ROS into the extracellular space where these metabolites could be readily detected by luminol-peroxidase and, to a lesser extent, 2',7'-dichlorodihydrofluorescein. However, such sensitivity to extracellular ROS meant that these assays were particularly vulnerable to interference by leucocytes. The remaining reagents predominantly elicited ROS generation by the sperm mitochondria and could be optimally detected by MitoSOX Red and DHE. Examination of spontaneous ROS generation by defective human spermatozoa revealed that MitoSOX Red was the most effective indicator of oxidative stress, thereby emphasizing the general importance of mitochondrial dysregulation in the aetiology of defective sperm function. © 2013 American Society of Andrology and European Academy of Andrology.

  12. Superoxide dismutases and glutaredoxins have a distinct role in the response of Candida albicans to oxidative stress generated by the chemical compounds menadione and diamide

    Directory of Open Access Journals (Sweden)

    Guilherme Maranhão Chaves

    2012-12-01

    Full Text Available To cope with oxidative stress, Candida albicans possesses several enzymes involved in a number of biological processes, including superoxide dismutases (Sods and glutaredoxins (Grxs. The resistance of C. albicans to reactive oxygen species is thought to act as a virulence factor. Genes such as SOD1 and GRX2, which encode for a Sod and Grx, respectively, in C. albicans are widely recognised to be important for pathogenesis. We generated a double mutant, Δgrx2/sod1, for both genes. This strain is very defective in hyphae formation and is susceptible to killing by neutrophils. When exposed to two compounds that generate reactive oxygen species, the double null mutant was susceptible to menadione and resistant to diamide. The reintegration of the SOD1 gene in the null mutant led to recovery in resistance to menadione, whereas reintegration of the GRX2 gene made the null mutant sensitive to diamide. Despite having two different roles in the responses to oxidative stress generated by chemical compounds, GRX2 and SOD1 are important for C. albicans pathogenesis because the double mutant Δgrx2/sod1 was very susceptible to neutrophil killing and was defective in hyphae formation in addition to having a lower virulence in an animal model of systemic infection.

  13. The antimalarial activities of methylene blue and the 1,4-naphthoquinone 3-[4-(trifluoromethyl)benzyl]-menadione are not due to inhibition of the mitochondrial electron transport chain.

    Science.gov (United States)

    Ehrhardt, Katharina; Davioud-Charvet, Elisabeth; Ke, Hangjun; Vaidya, Akhil B; Lanzer, Michael; Deponte, Marcel

    2013-05-01

    Methylene blue and a series of recently developed 1,4-naphthoquinones, including 3-[4-(substituted)benzyl]-menadiones, are potent antimalarial agents in vitro and in vivo. The activity of these structurally diverse compounds against the human malaria parasite Plasmodium falciparum might involve their peculiar redox properties. According to the current theory, redox-active methylene blue and 3-[4-(trifluoromethyl)benzyl]-menadione are "subversive substrates." These agents are thought to shuttle electrons from reduced flavoproteins to acceptors such as hemoglobin-associated or free Fe(III)-protoporphyrin IX. The reduction of Fe(III)-protoporphyrin IX could subsequently prevent essential hemoglobin digestion and heme detoxification in the parasite. Alternatively, owing to their structures and redox properties, methylene blue and 1,4-naphthoquinones might also affect the mitochondrial electron transport chain. Here, we tested the latter hypothesis using an established system of transgenic P. falciparum cell lines and the antimalarial agents atovaquone and chloroquine as controls. In contrast to atovaquone, methylene blue and 3-[4-(trifluoromethyl)benzyl]-menadione do not inhibit the mitochondrial electron transport chain. A systematic comparison of the morphologies of drug-treated parasites furthermore suggests that the three drugs do not share a mechanism of action. Our findings support the idea that methylene blue and 3-[4-(trifluoromethyl)benzyl]-menadione exert their antimalarial activity as redox-active subversive substrates.

  14. Enhanced

    Directory of Open Access Journals (Sweden)

    Martin I. Bayala

    2014-06-01

    Full Text Available Land Surface Temperature (LST is a key parameter in the energy balance model. However, the spatial resolution of the retrieved LST from sensors with high temporal resolution is not accurate enough to be used in local-scale studies. To explore the LST–Normalised Difference Vegetation Index relationship potential and obtain thermal images with high spatial resolution, six enhanced image sharpening techniques were assessed: the disaggregation procedure for radiometric surface temperatures (TsHARP, the Dry Edge Quadratic Function, the Difference of Edges (Ts∗DL and three models supported by the relationship of surface temperature and water stress of vegetation (Normalised Difference Water Index, Normalised Difference Infrared Index and Soil wetness index. Energy Balance Station data and in situ measurements were used to validate the enhanced LST images over a mixed agricultural landscape in the sub-humid Pampean Region of Argentina (PRA, during 2006–2010. Landsat Thematic Mapper (TM and Moderate Resolution Imaging Spectroradiometer (EOS-MODIS thermal datasets were assessed for different spatial resolutions (e.g., 960, 720 and 240 m and the performances were compared with global and local TsHARP procedures. Results suggest that the Ts∗DL technique is the most adequate for simulating LST to high spatial resolution over the heterogeneous landscape of a sub-humid region, showing an average root mean square error of less than 1 K.

  15. Comparison of gene expression signatures of diamide, H2O2 and menadione exposed Aspergillus nidulans cultures – linking genome-wide transcriptional changes to cellular physiology

    Science.gov (United States)

    Pócsi, István; Miskei, Márton; Karányi, Zsolt; Emri, Tamás; Ayoubi, Patricia; Pusztahelyi, Tünde; Balla, György; Prade, Rolf A

    2005-01-01

    Background In addition to their cytotoxic nature, reactive oxygen species (ROS) are also signal molecules in diverse cellular processes in eukaryotic organisms. Linking genome-wide transcriptional changes to cellular physiology in oxidative stress-exposed Aspergillus nidulans cultures provides the opportunity to estimate the sizes of peroxide (O22-), superoxide (O2•-) and glutathione/glutathione disulphide (GSH/GSSG) redox imbalance responses. Results Genome-wide transcriptional changes triggered by diamide, H2O2 and menadione in A. nidulans vegetative tissues were recorded using DNA microarrays containing 3533 unique PCR-amplified probes. Evaluation of LOESS-normalized data indicated that 2499 gene probes were affected by at least one stress-inducing agent. The stress induced by diamide and H2O2 were pulse-like, with recovery after 1 h exposure time while no recovery was observed with menadione. The distribution of stress-responsive gene probes among major physiological functional categories was approximately the same for each agent. The gene group sizes solely responsive to changes in intracellular O22-, O2•- concentrations or to GSH/GSSG redox imbalance were estimated at 7.7, 32.6 and 13.0 %, respectively. Gene groups responsive to diamide, H2O2 and menadione treatments and gene groups influenced by GSH/GSSG, O22- and O2•- were only partly overlapping with distinct enrichment profiles within functional categories. Changes in the GSH/GSSG redox state influenced expression of genes coding for PBS2 like MAPK kinase homologue, PSK2 kinase homologue, AtfA transcription factor, and many elements of ubiquitin tagging, cell division cycle regulators, translation machinery proteins, defense and stress proteins, transport proteins as well as many enzymes of the primary and secondary metabolisms. Meanwhile, a separate set of genes encoding transport proteins, CpcA and JlbA amino acid starvation-responsive transcription factors, and some elements of sexual development

  16. Laser flash photolysis and magnetic-field-effect studies on interaction of thymine and thymidine with menadione: role of sugar in controlling reaction pattern

    Directory of Open Access Journals (Sweden)

    Adity Bose, Debarati Dey and Samita Basu

    2008-01-01

    Full Text Available The magnetic field effect (MFE in conjunction with laser flash photolysis has been used for the study of the interaction of one of the small drug like quinone molecules, 2-methyl, 1,4-naphthoquinone, commonly known as menadione (MQ, with one of the DNA bases, thymine (THN, and its corresponding nucleoside, thymidine (THDN, in acetonitrile (ACN and sodium dodecylsulfate (SDS micelles. It has been observed that THN undergoes electron transfer (ET and hydrogen (H abstraction with MQ, while THDN undergoes only H abstraction in both the media. However, our earlier studies showed that a purine base, adenine (ADN, and its nucleoside, 2'-deoxyadenosine (ADS, undergo ET in ACN and H abstraction in SDS. Here we have attempted to explain the differences in the reactions of these DNA bases with MQ. We also reveal the crucial role of a sugar unit in altering the behavior of purine and pyrimidine bases with respect to ET and H abstraction.

  17. Laser flash photolysis and magnetic-field-effect studies on interaction of thymine and thymidine with menadione: role of sugar in controlling reaction pattern

    Science.gov (United States)

    Bose, Adity; Dey, Debarati; Basu, Samita

    2008-04-01

    The magnetic field effect (MFE) in conjunction with laser flash photolysis has been used for the study of the interaction of one of the small drug like quinone molecules, 2-methyl, 1,4-naphthoquinone, commonly known as menadione (MQ), with one of the DNA bases, thymine (THN), and its corresponding nucleoside, thymidine (THDN), in acetonitrile (ACN) and sodium dodecylsulfate (SDS) micelles. It has been observed that THN undergoes electron transfer (ET) and hydrogen (H) abstraction with MQ, while THDN undergoes only H abstraction in both the media. However, our earlier studies showed that a purine base, adenine (ADN), and its nucleoside, 2'-deoxyadenosine (ADS), undergo ET in ACN and H abstraction in SDS. Here we have attempted to explain the differences in the reactions of these DNA bases with MQ. We also reveal the crucial role of a sugar unit in altering the behavior of purine and pyrimidine bases with respect to ET and H abstraction.

  18. Laser flash photolysis and magnetic-field-effect studies on interaction of thymine and thymidine with menadione: role of sugar in controlling reaction pattern

    International Nuclear Information System (INIS)

    Bose, Adity; Dey, Debarati; Basu, Samita

    2008-01-01

    The magnetic field effect (MFE) in conjunction with laser flash photolysis has been used for the study of the interaction of one of the small drug like quinone molecules, 2-methyl, 1,4-naphthoquinone, commonly known as menadione (MQ), with one of the DNA bases, thymine (THN), and its corresponding nucleoside, thymidine (THDN), in acetonitrile (ACN) and sodium dodecylsulfate (SDS) micelles. It has been observed that THN undergoes electron transfer (ET) and hydrogen (H) abstraction with MQ, while THDN undergoes only H abstraction in both the media. However, our earlier studies showed that a purine base, adenine (ADN), and its nucleoside, 2'-deoxyadenosine (ADS), undergo ET in ACN and H abstraction in SDS. Here we have attempted to explain the differences in the reactions of these DNA bases with MQ. We also reveal the crucial role of a sugar unit in altering the behavior of purine and pyrimidine bases with respect to ET and H abstraction

  19. Laser flash photolysis and magnetic-field-effect studies on interaction of thymine and thymidine with menadione: role of sugar in controlling reaction pattern

    Energy Technology Data Exchange (ETDEWEB)

    Bose, Adity; Dey, Debarati; Basu, Samita [Chemical Sciences Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata-700 064 (India)], E-mail: samita.basu@saha.ac.in

    2008-04-01

    The magnetic field effect (MFE) in conjunction with laser flash photolysis has been used for the study of the interaction of one of the small drug like quinone molecules, 2-methyl, 1,4-naphthoquinone, commonly known as menadione (MQ), with one of the DNA bases, thymine (THN), and its corresponding nucleoside, thymidine (THDN), in acetonitrile (ACN) and sodium dodecylsulfate (SDS) micelles. It has been observed that THN undergoes electron transfer (ET) and hydrogen (H) abstraction with MQ, while THDN undergoes only H abstraction in both the media. However, our earlier studies showed that a purine base, adenine (ADN), and its nucleoside, 2'-deoxyadenosine (ADS), undergo ET in ACN and H abstraction in SDS. Here we have attempted to explain the differences in the reactions of these DNA bases with MQ. We also reveal the crucial role of a sugar unit in altering the behavior of purine and pyrimidine bases with respect to ET and H abstraction.

  20. Higher Vulnerability of Menadione-Exposed Cortical Astrocytes of Glutaryl-CoA Dehydrogenase Deficient Mice to Oxidative Stress, Mitochondrial Dysfunction, and Cell Death: Implications for the Neurodegeneration in Glutaric Aciduria Type I.

    Science.gov (United States)

    Rodrigues, Marília Danyelle Nunes; Seminotti, Bianca; Zanatta, Ângela; de Mello Gonçalves, Aline; Bellaver, Bruna; Amaral, Alexandre Umpierrez; Quincozes-Santos, André; Goodman, Stephen Irwin; Woontner, Michael; Souza, Diogo Onofre; Wajner, Moacir

    2017-08-01

    Patients affected by glutaric aciduria type I (GA-I) show progressive cortical leukoencephalopathy whose pathogenesis is poorly known. In the present work, we exposed cortical astrocytes of wild-type (Gcdh +/+ ) and glutaryl-CoA dehydrogenase knockout (Gcdh -/- ) mice to the oxidative stress inducer menadione and measured mitochondrial bioenergetics, redox homeostasis, and cell viability. Mitochondrial function (MTT and JC1-mitochondrial membrane potential assays), redox homeostasis (DCFH oxidation, nitrate and nitrite production, GSH concentrations and activities of the antioxidant enzymes SOD and GPx), and cell death (propidium iodide incorporation) were evaluated in primary cortical astrocyte cultures of Gcdh +/+ and Gcdh -/- mice unstimulated and stimulated by menadione. We also measured the pro-inflammatory response (TNFα levels, IL1-β and NF-ƙB) in unstimulated astrocytes obtained from these mice. Gcdh -/- mice astrocytes were more vulnerable to menadione-induced oxidative stress (decreased GSH concentrations and altered activities of the antioxidant enzymes), mitochondrial dysfunction (decrease of MTT reduction and JC1 values), and cell death as compared with Gcdh +/+ astrocytes. A higher inflammatory response (TNFα, IL1-β and NF-ƙB) was also observed in Gcdh -/- mice astrocytes. These data indicate a higher susceptibility of Gcdh -/- cortical astrocytes to oxidative stress and mitochondrial dysfunction, probably leading to cell death. It is presumed that these pathomechanisms may contribute to the cortical leukodystrophy observed in GA-I patients.

  1. Enhancement of chemically induced reactive oxygen species production and DNA damage in human SH-SY5Y neuroblastoma cells by 872 MHz radiofrequency radiation

    Energy Technology Data Exchange (ETDEWEB)

    Luukkonen, Jukka [Department of Environmental Science, University of Kuopio, Bioteknia 2, P.O. Box 1627, FI-70211 Kuopio (Finland)], E-mail: Jukka.Luukkonen@uku.fi; Hakulinen, Pasi; Maeki-Paakkanen, Jorma [Department of Environmental Health, National Public Health Institute, P.O. Box 95, FI-70701 Kuopio (Finland); Juutilainen, Jukka; Naarala, Jonne [Department of Environmental Science, University of Kuopio, Bioteknia 2, P.O. Box 1627, FI-70211 Kuopio (Finland)

    2009-03-09

    The objective of the study was to investigate effects of 872 MHz radiofrequency (RF) radiation on intracellular reactive oxygen species (ROS) production and DNA damage at a relatively high SAR value (5 W/kg). The experiments also involved combined exposure to RF radiation and menadione, a chemical inducing intracellular ROS production and DNA damage. The production of ROS was measured using the fluorescent probe dichlorofluorescein and DNA damage was evaluated by the Comet assay. Human SH-SY5Y neuroblastoma cells were exposed to RF radiation for 1 h with or without menadione. Control cultures were sham exposed. Both continuous waves (CW) and a pulsed signal similar to that used in global system for mobile communications (GSM) mobile phones were used. Exposure to the CW RF radiation increased DNA breakage (p < 0.01) in comparison to the cells exposed only to menadione. Comparison of the same groups also showed that ROS level was higher in cells exposed to CW RF radiation at 30 and 60 min after the end of exposure (p < 0.05 and p < 0.01, respectively). No effects of the GSM signal were seen on either ROS production or DNA damage. The results of the present study suggest that 872 MHz CW RF radiation at 5 W/kg might enhance chemically induced ROS production and thus cause secondary DNA damage. However, there is no known mechanism that would explain such effects from CW RF radiation but not from GSM modulated RF radiation at identical SAR.

  2. Enhancement of chemically induced reactive oxygen species production and DNA damage in human SH-SY5Y neuroblastoma cells by 872 MHz radiofrequency radiation

    International Nuclear Information System (INIS)

    Luukkonen, Jukka; Hakulinen, Pasi; Maeki-Paakkanen, Jorma; Juutilainen, Jukka; Naarala, Jonne

    2009-01-01

    The objective of the study was to investigate effects of 872 MHz radiofrequency (RF) radiation on intracellular reactive oxygen species (ROS) production and DNA damage at a relatively high SAR value (5 W/kg). The experiments also involved combined exposure to RF radiation and menadione, a chemical inducing intracellular ROS production and DNA damage. The production of ROS was measured using the fluorescent probe dichlorofluorescein and DNA damage was evaluated by the Comet assay. Human SH-SY5Y neuroblastoma cells were exposed to RF radiation for 1 h with or without menadione. Control cultures were sham exposed. Both continuous waves (CW) and a pulsed signal similar to that used in global system for mobile communications (GSM) mobile phones were used. Exposure to the CW RF radiation increased DNA breakage (p < 0.01) in comparison to the cells exposed only to menadione. Comparison of the same groups also showed that ROS level was higher in cells exposed to CW RF radiation at 30 and 60 min after the end of exposure (p < 0.05 and p < 0.01, respectively). No effects of the GSM signal were seen on either ROS production or DNA damage. The results of the present study suggest that 872 MHz CW RF radiation at 5 W/kg might enhance chemically induced ROS production and thus cause secondary DNA damage. However, there is no known mechanism that would explain such effects from CW RF radiation but not from GSM modulated RF radiation at identical SAR

  3. The Electroporation as a Tool for Studying the Role of Plasma Membrane in the Mechanism of Cytotoxicity of Bisphosphonates and Menadione.

    Science.gov (United States)

    Šilkūnas, Mantas; Saulė, Rita; Batiuškaitė, Danutė; Saulis, Gintautas

    2016-10-01

    In this study, the role of the cell plasma membrane as a barrier in the mechanism of the cytotoxicity of nitrogen-containing bisphosphonates and menadione was studied, and the possibility of increasing the efficiency of bisphosphonates and menadione (vitamin K 3 ) as chemotherapeutic agents by permeabilizing the cell plasma membrane has been investigated in vitro. The plasma membrane barrier was reduced by electropermeabilization with the pulse of strong electric field. Two membrane-impermeant bisphosphonates with different hydrophilicities were chosen as study objects: ibandronate and pamidronate. For the comparison, an amphiphilic vitamin K 3 , which is able to cross the cell membrane, was studied as well. The impact of nitrogen-containing bisphosphonates and vitamin K 3 on MH-22A cells viability was evaluated for the case of long (9 days) and short (20 min) exposure. When cells were cultured in the medium with vitamin K 3 for 9-10 days, it exhibited toxicity of 50 % over the control at 6.2 µM for mouse hepatoma MH-22A cells. Ibandronate and pamidronate were capable of reducing drastically the cell viability only in the case of long 9-days incubation and at high concentrations (~20 µM for pamidronate and over 100 µM for ibandronate). Single, square-wave electric pulse with the duration of 100 µs and the field strength of 2 kV/cm was used to electroporate mouse hepatoma MH-22A cells in vitro. The results obtained here showed that the combination of the exposure of cells to membrane-impermeable bisphosphonates pamidronate and ibandronate with electropermeabilization of the cell plasma membrane did not increase their cytotoxicity. In the case of membrane-permeable vitamin K 3 , cell electropermeabilization did increase vitamin K 3 killing efficiency. However, this increase was not substantial, within the range of 20-30 % depending on the duration of the exposure. Electropermeabilization improved cytotoxic effect of vitamin K 3 but not of pamidronate

  4. Synergistic antitumor cytotoxic actions of ascorbate and menadione on human prostate (DU145) cancer cells in vitro: nucleus and other injuries preceding cell death by autoschizis.

    Science.gov (United States)

    Gilloteaux, Jacques; Jamison, James M; Neal, Deborah; Summers, Jack L

    2014-04-01

    Scanning (SEM) and transmission electron microscopy (TEM) were used to characterize the cytotoxic effects of ascorbate (VC), menadione (VK3), or a VC:VK3 combination on a human prostate carcinoma cell line (DU145) following a 1-h vitamin treatment and a subsequent 24-h incubation in culture medium. Cell alterations examined by light and electron microscopy were treatment-dependent with VC + VK3 >VK3 > VC > Sham. Oxidative stress-induced damage was found in most organelles. This report describes injuries in the tumor cell nucleus (chromatin and nucleolus), mitochondria, endomembranes, lysosomal bodies (autophagocytoses) and inclusions. Morphologic alterations suggest that cytoskeleton damage is likely responsible for the superficial cytoplasmic changes, including major changes in cell shape and size and the self-excising phenomena. Unlike apoptotic bodies, the excised pieces contain ribonucleoproteins, but not organelles. These deleterious events cause a progressive, significant reduction in the tumor cell size. During nuclear alterations, the nuclei maintain their envelope during chromatolysis and karyolysis until cell death, while nucleoli undergo a characteristic segregation of their components. In addition, changes in fat and glycogen storage are consistent the cytotoxic and metabolic alterations caused by the respective treatments. All cellular ultrastructural changes are consistent with cell death by autoschizis and not apoptosis or other kinds of cell death.

  5. Menadione and ethacrynic acid inhibit the hypoxia-inducible factor (HIF) pathway by disrupting HIF-1α interaction with p300.

    Science.gov (United States)

    Na, Yu-Ran; Han, Ki-Cheol; Park, Hyunsung; Yang, Eun Gyeong

    2013-05-17

    Hypoxia is a general characteristic of most solid malignancies and intimately related to neoplastic diseases and cancer progression. Homeostatic response to hypoxia is primarily mediated by hypoxia inducible factor (HIF)-1α that elicits transcriptional activity through recruitment of the CREB binding protein (CBP)/p300 coactivator. Targeted blockade of HIF-1α binding to CBP/p300 would thus constitute a novel approach for cancer treatment by suppressing tumor angiogenesis and metastasis. Here, we identified inhibitors against the interaction between HIF-1α and p300 by a fluorescence polarization-based assay employing a fluorescently-labeled peptide containing the C-terminal activation domain of HIF-1α. Two small molecule inhibitors, menadione (MD) and ethacrynic acid (EA), were found to decrease expression of luciferase under the control of hypoxia-responsive elements in hypoxic cells as well as to efficiently block the interaction between the full-length HIF-1α and p300. While these compounds did not alter the expression level of HIF-1α, they down-regulated expression of a HIF-1α target vascular endothelial growth factor (VEGF) gene. Considering hypoxia-induced VEGF expression leading to highly aggressive tumor growth, MD and EA may provide new scaffolds for development of tumor therapeutic reagents as well as tools for a better understanding of HIF-1α-mediated hypoxic regulation. Copyright © 2013 Elsevier Inc. All rights reserved.

  6. Synthesis and solubility measurement in supercritical carbon dioxide of two solid derivatives of 2-methylnaphthalene-1,4-dione (menadione): 2-(Benzylamino)-3-methylnaphthalene-1,4-dione and 3-(phenethylamino)-2-methylnaphthalene-1,4-dione

    International Nuclear Information System (INIS)

    Zacconi, Flavia C.; Nuñez, Olga N.; Cabrera, Adolfo L.; Valenzuela, Loreto M.

    2016-01-01

    Highlights: • Two menadione derivatives were synthesized, purified and characterized. • Solubility of menadione derivatives in SC-CO 2 was measured at T < 333 K, p < 28 MPa. • Thermodynamic consistency of solubility data measured was evaluated. • Solubility data was correlated in terms of temperature and CO 2 density. - Abstract: Synthesis of two solid derivatives of vitamin K 3 (2-methylnaphthalene-1,4-dione or menadione), 2-(benzylamino)-3-methylnaphthalene-1,4-dione and 3-(phenethylamino)-2-methylnaphthalene-1,4-dione was completed using a 1,4 Michael addition reaction at 323 K in an inert atmosphere, with reaction yields of 62% mol·mol −1 and 71% mol·mol −1 , respectively, and a purity grade of 98% mol·mol −1 for each component. Isothermal solubility (mole fraction) of each solid derivative in supercritical carbon dioxide was performed using an analytic-recirculation methodology, with direct determination of the molar composition of the carbon dioxide-rich phase by using high performance liquid chromatography, at temperatures of (313, 323 and 333) K and pressures from (8–28) MPa. Results indicated that the range of measured solubilities were from (59 × 10 −6 to 368 × 10 −6 ) mol·mol −1 for solid 2-(benzylamino)-3-methylnaphthalene-1,4-dione and from (40 × 10 −6 to 205 × 10 −6 ) mol·mol −1 for solid 3-(phenethylamino)-2-methylnaphthalene-1,4-dione. The experimental solubility was validated using three approaches, estimating the combined expanded uncertainty of measurement for each solubility data point, evaluating the thermodynamic consistency of the data utilizing a test based on the Gibbs–Duhem equation, and verifying the self-consistency by correlating the experimental solubility values with a semi-empirical model as a function of temperature, pressure and pure carbon dioxide density.

  7. Pharmacodynamic evaluation of the activity of antibiotics against hemin- and menadione-dependent small-colony variants of Staphylococcus aureus in models of extracellular (broth) and intracellular (THP-1 monocytes) infections.

    Science.gov (United States)

    Garcia, L G; Lemaire, S; Kahl, B C; Becker, K; Proctor, R A; Denis, O; Tulkens, P M; Van Bambeke, F

    2012-07-01

    Staphylococcus aureus small-colony variants (SCVs) persist intracellularly, which may contribute to persistence/recurrence of infections and antibiotic failure. We have studied the intracellular fate of menD and hemB mutants (corresponding to menadione- and hemin-dependent SCVs, respectively) of the COL methicillin-resistant S. aureus (MRSA) strain and the antibiotic pharmacodynamic profile against extracellular (broth) and intracellular (human THP-1 monocytes) bacteria. Compared to the parental strain, SCVs showed slower extracellular growth (restored upon medium supplementation with menadione or hemin), reduced phagocytosis, and, for the menD SCV, lower intracellular counts at 24 h postinfection. Against extracellular bacteria, daptomycin, gentamicin, rifampin, moxifloxacin, and oritavancin showed similar profiles of activity against all strains, with a static effect obtained at concentrations close to their MICs and complete eradication as maximal effect. In contrast, vancomycin was not bactericidal against SCVs. Against intracellular bacteria, concentration-effect curves fitted sigmoidal regressions for vancomycin, daptomycin, gentamicin, and rifampin (with maximal effects lower than a 2-log decrease in CFU) but biphasic regressions (with a maximal effect greater than a 3-log decrease in CFU) for moxifloxacin and oritavancin, suggesting a dual mode of action against intracellular bacteria. For all antibiotics, these curves were indistinguishable between the strains investigated, except for the menD mutant, which systematically showed a lower amplitude of the concentration-effect response, with markedly reduced minimal efficacy (due to slower growth) but no change in maximal efficacy. The data therefore show that the maximal efficacies of antibiotics are similar against normal-phenotype and menadione- and hemin-dependent strains despite their different intracellular fates, with oritavancin, and to some extent moxifloxacin, being the most effective.

  8. Development and validation of the first assay method coupling liquid chromatography with chemiluminescence for the simultaneous determination of menadione and its thioether conjugates in rat plasma.

    Science.gov (United States)

    Elgawish, Mohamed Saleh; Shimomai, Chikako; Kishikawa, Naoya; Ohyama, Kaname; Wada, Mitsuhiro; Kuroda, Naotaka

    2013-09-16

    Menadione (2-methyl-1,4-naphthoquinone, MQ), a component of multivitamin drugs with antihemorrhagic, antineoplastic, and antimalarial activity, is frequently used to investigate quinone-induced cytotoxicity. The formation of MQ conjugates with glutathione (GSH) by Michael addition and subsequent biotransformation to yield N-acetyl-l-cysteine conjugates is believed to be an important detoxification process. However, the resulting conjugates, 2-methyl-3-(glutathione-S-yl)-1,4-naphthoquinone (MQ-GS) and 2-methyl-3-(N-acetyl-l-cysteine-S-yl)-1,4-naphthoquinone (MQ-NAC), retain the ability to redox cycle and to arylate cellular nucleophiles. Although the nephrotoxicity and hepatotoxicity of MQ-thiol conjugates have been reported in vitro, methods for their determination in vivo have yet to be published. Herein, a highly sensitive, simple, and selective HPLC-chemiluminescence (HPLC-CL) coupled method is reported, allowing for the first time the simultaneous determination of MQ, MQ-GS, and MQ-NAC in rat plasma after MQ administration. Our method exploits the unique redox characteristics of MQ, MQ-GS, and MQ-NAC to react with dithiothreitol (DTT) to liberate reactive oxygen species (ROS) which are detected by a CL assay using luminol as a CL probe. To verify the proposed mechanism, MQ-GS and MQ-NAC were synthetically prepared. Specimen preparation involved solid-phase extraction on an Oasis HLB cartridge followed by isocratic elution on an ODS column. No interference from endogenous substances was detected. Linearity was observed in the range of 5-120 nM for MQ-GS and MQ-NAC and 10-240 nM for MQ, with detection limits (S/N of 3) of 1.4, 0.8, and 128 fmol for MQ-GS, MQ-NAC, and MQ, respectively. The application of our method reported here is the first to extensively study the stability and reversibility of thiol-quinones.

  9. High performance liquid chromatography analysis of aliphatic thiols in alimentary supplements and pharmaceuticals using menadione as a new useful derivatization reagent.

    Science.gov (United States)

    Gatti, Rita; Vitellaro, Valeria

    2013-12-04

    The use of menadione (MD) as a pre-column reagent for high performance liquid chromatography (HPLC) analysis of aliphatic thiols is proposed. The reaction was carried out for 5 min at room temperature and pH 8.5. The developed method was applied to the N-acetylcysteine (NAC) analysis of alimentary supplements and pharmaceutical formulations. The effect of the complex matrix was evaluated by the study of the thiol derivatization reaction both in standard and in placebo solutions. The yield of NAC-MD adduct was found to be quantitative at a reagent to thiol molar ratio of about 4 in comparison with an authentic specimen of synthesized NAC adduct, which was characterized by (1)H NMR, IR and UV. The routine chromatographic separations were performed on a Synergi MAX-RP column using a mobile phase consisting of methanol/triethylammonium (TEA) phosphate buffer (pH 3; 0.05 mol L(-1)) 70:30 (v/v) at a flow-rate of 0.4 mL min(-1). UV-diode array detection was used setting the wavelength at λ=260 nm. The validation parameters such as linearity, sensitivity, accuracy, precision, selectivity and ruggedness were found to be highly satisfactory. Similar linear responses were observed by standard and placebo solutions (determination coefficient: 0.9996). Limit of detection was about 0.019 μg g(-1). Intra-day precision (relative standard deviation, R.S.D.) was ≤0.81% for NAC to internal standard (IS) peak area ratio, ≤0.28% and ≤0.32%, respectively, for NAC and IS retention times (tR), without significant differences between intra- and inter-day data. NAC recovery studies gave good results (100.12%) with R.S.D.=1.05%. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. Differential behaviors of trastuzumab-sensitive and -resistant SKBR3 cells treated with menadione reveal the involvement of Notch1/Akt/FOXO1 signaling elements.

    Science.gov (United States)

    Sajadimajd, Soraya; Yazdanparast, Razieh

    2015-10-01

    Given that HER2 serves as a putative target for therapy in HER2-positive breast cancer, intrinsic and/or acquired resistance to trastuzumab (T) has been proposed to be the major obstacle in treatments. In addition, chemoresistance is commonly attributed to increased antioxidant capacity. In that regard, we evaluated the effect of menadione (M) alone and/or its combination with trastuzumab on proliferation, intracellular GSH and ROS contents as well as HER2 and Notch1 signaling pathways in both trastuzumab-resistant (SKBR3(R)) and -sensitive SKBR3 (SKBR3(S)) cells. In spite of increased level of ROS and reduced level of GSH in M-treated SKBR3(S) cells, M-treated SKBR3(R) cells showed a decreased content of ROS and GSH compared to untreated cells. However, M/T co-treatment of SKBR3 cells indicated no effect on ROS content, while decreased the level of GSH compared to untreated control cells. Based on the extent of apoptosis, colony formation and wound healing assays, M alone, and/or in combination with T had a stronger inhibitory effect on proliferation of SKBR3(R) cells relative to SKBR3(S) cells. These effects might be due to the stronger effects of M and/or M/T on downregulation of p-Akt, Hes1, NICD, and upregulation of FOXO1 among SKBR3(R) cells relative to the sensitive SKBR3 cells. These findings would certainly shed light on some of the signaling factors involved in induction of trastuzumab resistance and would be of value in designing more efficient chemosensitization strategies.

  11. Ascorbate/menadione-induced oxidative stress kills cancer cells that express normal or mutated forms of the oncogenic protein Bcr-Abl. An in vitro and in vivo mechanistic study.

    Science.gov (United States)

    Beck, Raphaël; Pedrosa, Rozangela Curi; Dejeans, Nicolas; Glorieux, Christophe; Levêque, Philippe; Gallez, Bernard; Taper, Henryk; Eeckhoudt, Stéphane; Knoops, Laurent; Calderon, Pedro Buc; Verrax, Julien

    2011-10-01

    Numerous studies suggest that generation of oxidative stress could be useful in cancer treatment. In this study, we evaluated, in vitro and in vivo, the antitumor potential of oxidative stress induced by ascorbate/menadione (asc/men). This combination of a reducing agent (ascorbate) and a redox active quinone (menadione) generates redox cycling leading to formation of reactive oxygen species (ROS). Asc/men was tested in several cell types including K562 cells (a stable human-derived leukemia cell line), freshly isolated leukocytes from patients with chronic myeloid leukemia, BaF3 cells (a murine pro-B cell line) transfected with Bcr-Abl and peripheral blood leukocytes derived from healthy donors. Although these latter cells were resistant to asc/men, survival of all the other cell lines was markedly reduced, including the BaF3 cells expressing either wild-type or mutated Bcr-Abl. In a standard in vivo model of subcutaneous tumor transplantation, asc/men provoked a significant delay in the proliferation of K562 and BaF3 cells expressing the T315I mutated form of Bcr-Abl. No effect of asc/men was observed when these latter cells were injected into blood of mice most probably because of the high antioxidant potential of red blood cells, as shown by in vitro experiments. We postulate that cancer cells are more sensitive to asc/men than healthy cells because of their lack of antioxidant enzymes, mainly catalase. The mechanism underlying this cytotoxicity involves the oxidative cleavage of Hsp90 with a subsequent loss of its chaperone function thus leading to degradation of wild-type and mutated Bcr-Abl protein.

  12. Intracellular forms of menadione-dependent small-colony variants of methicillin-resistant Staphylococcus aureus are hypersusceptible to β-lactams in a THP-1 cell model due to cooperation between vacuolar acidic pH and oxidant species.

    Science.gov (United States)

    Garcia, Laetitia G; Lemaire, Sandrine; Kahl, Barbara C; Becker, Karsten; Proctor, Richard A; Tulkens, Paul M; Van Bambeke, Françoise

    2012-12-01

    Phagocytosed methicillin-resistant Staphylococcus aureus (MRSA) are susceptible to β-lactams because of an acid-induced conformational change of penicillin-binding protein (PBP) 2a within phagolysosomes. We have examined whether this mechanism applies to menD and hemB small-colony variants (SCVs) of the COL MRSA strain, using cloxacillin, meropenem, doripenem, and vancomycin as comparator. Intracellularly, the change in cfu from post-phagocytosis inoculum was measured after 24 h of incubation with antibiotics combined or not with N-acetylcysteine (NAC; oxidant species scavenger); the relative potency (C(s)) was calculated from the Hill equation of concentration-response curves. Extracellularly, the effect of a pre-incubation with H(2)O(2) was determined on MICs and killing at pH 7.4 and 5.5. Intracellularly, the β-lactam C(s) was similar for the COL strain and the hemB mutant and not modified or slightly decreased (2- to 16-fold) by NAC. In contrast, the C(s) was 100- to 900-fold lower for the menD mutant, but similar to that for the COL strain when NAC was present. Extracellularly, β-lactam MICs were markedly reduced at pH 5.5 for the parental strain and the haemin-supplemented hemB mutant, with limited additional effect of pre-incubation with H(2)O(2). In contrast, MICs remained elevated at pH 5.5 for the menD mutant (supplemented with menadione sodium bisulphite or not), but were 7-10 dilutions lower after pre-incubation with H(2)O(2). Vancomycin MICs were unaltered in all conditions, with no marked effect of NAC on C(s). Cooperation between acidic pH and oxidant species confers high potency to β-lactams against intracellular forms of menD SCVs of MRSA.

  13. Enhanced Oxidative Bioremediation of cis-dichloroethene (cis-DCE) and Vinyl Chloride (VC) using Electron Shuttles

    Science.gov (United States)

    2009-07-01

    NA NA 5.23E-013 mg/L 0.113 2, 5 Vitamin K3 , Menadione, Menadione sodium bisulfate, Menaquinone 2-Methyl-1,4-naphthoquinone 58-27-5 C11H8O2 172.18...version of vitamin K3 which is known to have electron shuttling ability. Thus, bisulfate modification resulted in loss of activity. AQS and lawsone

  14. Tip enhancement

    CERN Document Server

    Kawata, Satoshi

    2007-01-01

    This book discusses the recent advances in the area of near-field Raman scattering, mainly focusing on tip-enhanced and surface-enhanced Raman scattering. Some of the key features covered here are the optical structuring and manipulations, single molecule sensitivity, analysis of single-walled carbon nanotubes, and analytic applications in chemistry, biology and material sciences. This book also discusses the plasmonic materials for better enhancement, and optical antennas. Further, near-field microscopy based on second harmonic generation is also discussed. Chapters have been written by some of the leading scientists in this field, who present some of their recent work in this field.·Near-field Raman scattering·Tip-enhanced Raman spectroscopy·Surface-enhanced Raman spectroscopy·Nano-photonics·Nanoanalysis of Physical, chemical and biological materials beyond the diffraction limits·Single molecule detection

  15. Biocatalyst Enhancement

    Science.gov (United States)

    The increasing availability of enzyme collections has assisted attempts by pharmaceutical producers to adopt green chemistry approaches to manufacturing. A joint effort between an enzyme producer and a pharmaceutical manufacturer has been enhanced over the past three years by ena...

  16. Drug-enhanced carbon monoxide production from heme by cytochrome P450 reductase

    Directory of Open Access Journals (Sweden)

    Dragic Vukomanovic

    2017-01-01

    Full Text Available Carbon monoxide (CO formed endogenously is considered to be cytoprotective, and the vast majority of CO formation is attributed to the degradation of heme by heme oxygenases-1 and -2 (HO-1, HO-2. Previously, we observed that brain microsomes containing HO-2 produced many-fold more CO in the presence of menadione and its congeners; herein we explored these observations further. We determined the effects of various drugs on CO production of rat brain microsomes and recombinant human cytochrome P450 reductase (CPR; CO was measured by gas chromatography with reductive detection. Brain microsomes of Sprague-Dawley rats or recombinant human cytochrome P450 reductase (CPR were incubated with NADPH and various drugs in closed vials in phosphate buffer at pH 7.4 and 37°C. After 15 minutes, the reaction was stopped by cooling in dry ice, and the headspace gas was analyzed for CO production using gas chromatography with reductive (mercuric oxide detection. We observed drug-enhanced CO production in the presence of both microsomes and recombinant CPR alone; the presence of HO was not required. A range of structurally diverse drugs were capable of amplifying this CO formation; these molecules had structures consistent with redox cycling capability. The addition of catalase to a reaction mixture, that contained activating drugs, inhibited the production of CO. Drug-enhanced CO formation can be catalyzed by CPR. The mechanism of CPR activation was not through classical drug-receptor mediation. Redox cycling may be involved in the drug-induced amplification of CO production by CPR through the production of reactive oxygen species.

  17. Speech enhancement

    CERN Document Server

    Benesty, Jacob; Chen, Jingdong

    2006-01-01

    We live in a noisy world! In all applications (telecommunications, hands-free communications, recording, human-machine interfaces, etc.) that require at least one microphone, the signal of interest is usually contaminated by noise and reverberation. As a result, the microphone signal has to be ""cleaned"" with digital signal processing tools before it is played out, transmitted, or stored.This book is about speech enhancement. Different well-known and state-of-the-art methods for noise reduction, with one or multiple microphones, are discussed. By speech enhancement, we mean not only noise red

  18. Influence of the protein kinase C activator phorbol myristate acetate on the intracellular activity of antibiotics against hemin- and menadione-auxotrophic small-colony variant mutants of Staphylococcus aureus and their wild-type parental strain in human THP-1 cells.

    Science.gov (United States)

    Garcia, Laetitia G; Lemaire, Sandrine; Kahl, Barbara C; Becker, Karsten; Proctor, Richard A; Tulkens, Paul M; Van Bambeke, Françoise

    2012-12-01

    In a previous study (L. G. Garcia et al., Antimicrob. Agents Chemother. 56:3700-3711, 2012), we evaluated the intracellular fate of menD and hemB mutants (corresponding to menadione- and hemin-dependent small-colony variants, respectively) of the parental COL methicillin-resistant Staphylococcus aureus strain and the pharmacodynamic profile of the intracellular activity of a series of antibiotics in human THP-1 monocytes. We have now examined the phagocytosis and intracellular persistence of the same strains in THP-1 cells activated by phorbol 12-myristate 13-acetate (PMA) and measured the intracellular activity of gentamicin, moxifloxacin, and oritavancin in these cells. Postphagocytosis intracellular counts and intracellular survival were lower in PMA-activated cells, probably due to their higher killing capacities. Gentamicin and moxifloxacin showed a 5- to 7-fold higher potency (lower static concentrations) against the parental strain, its hemB mutant, and the genetically complemented strain in PMA-activated cells and against the menD strain in both activated and nonactivated cells. This effect was inhibited when cells were incubated with N-acetylcysteine (a scavenger of oxidant species). In parallel, we observed that the MICs of these drugs were markedly reduced if bacteria had been preexposed to H(2)O(2). In contrast, the intracellular potency of oritavancin was not different in activated and nonactivated cells and was not decreased by the addition of N-acetylcysteine, regardless of the phenotype of the strains. The oritavancin MIC was also unaffected by preincubation of the bacteria with H(2)O(2). Thus, activation of THP-1 cells by PMA may increase the intracellular potency of certain antibiotics (probably due to synergy with reactive oxygen species), but this effect cannot be generalized to all antibiotics.

  19. Journal of Biosciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    ... oxyradicals invoked higher activity of antioxidant enzymes like superoxide dismutase and peroxidase under ambient UV, they also imposed limitation on the photosynthetic efficiency of PSII. Exclusion of UV components (UV-B 280–315 nm; UV-A 315–400 nm) translated to enhanced photosynthesis, growth and biomass.

  20. EDITORIAL: Enhancing nanolithography Enhancing nanolithography

    Science.gov (United States)

    Demming, Anna

    2012-01-01

    Lithography was invented in late 18th century Bavaria by an ambitious young playwright named Alois Senefelder. Senefelder experimented with stone, wax, water and ink in the hope of finding a way of reproducing text so that he might financially gain from a wider distribution of his already successful scripts. His discovery not only facilitated the profitability of his plays, but also provided the world with an affordable printing press that would ultimately democratize the dissemination of art, knowledge and literature. Since Senefelder, experiments in lithography have continued with a range of innovations including the use of electron beams and UV that allow increasingly higher-resolution features [1, 2]. Applications for this have now breached the limits of paper printing into the realms of semiconductor and microelectronic mechanical systems technology. In this issue, researchers demonstrate a technique for fabricating periodic features in poly(3,4-ethylene dioxythiophene)-poly(styrenesulfonate) (PEDOT-PSS) [3]. Their method combines field enhancements from silica nanospheres with laser-interference lithography to provide a means of patterning a polymer that has the potential to open the market of low-end, high-volume microelectronics. Laser-interference lithography has already been used successfully in patterning. Researchers in Korea used laser-interference lithography to generate stamps for imprinting a two-dimensional photonic crystal structure into green light emitting diodes (LEDs) [4]. The imprinted patterns comprised depressions 100 nm deep and 180 nm wide with a periodicity of 295 nm. In comparison with unpatterned LEDs, the intensity of photoluminescence was enhanced by a factor of seven in the LEDs that had the photonic crystal structures imprinted in them. The potential of exploiting field enhancements around nanostructures for new technologies has also attracted a great deal of attention. Researchers in the USA and Australia have used the field

  1. Progressivity Enhanced

    Directory of Open Access Journals (Sweden)

    Marko Hren

    2013-09-01

    Full Text Available Rather than a scientific text, the author contributes a concise memorandum from the originator of the idea who has managed the campaign for the conversion of the military barracks into a creative cluster between 1988 and 2002, when he parted ways with Metelkova due to conflicting views on the center’s future. His views shed light on a distant period of time from a perspective of a participant–observer. The information is abundantly supported by primary sources, also available online. However, some of the presented hypotheses are heavily influenced by his personal experiences of xenophobia, elitism, and predatorial behavior, which were already then discernible on the so-called alternative scene as well – so much so that they obstructed the implementation of progressive programs. The author claims that, in spite of the substantially different reality today, the myths and prejudices concerning Metelkova must be done away with in order to enhance its progressive nature. Above all, the paper calls for an objective view on internal antagonisms, mainly originating in deep class divisions between the users. These make a clear distinction between truly marginal ndividuals and the overambitious beau-bourgeois, as the author labels the large part of users of Metelkova of »his« time. On these grounds, he argues for a robust approach to ban all forms of xenophobia and self-ghettoization.

  2. Vitamins for enhancing plant resistance.

    Science.gov (United States)

    Boubakri, Hatem; Gargouri, Mahmoud; Mliki, Ahmed; Brini, Faiçal; Chong, Julie; Jbara, Moez

    2016-09-01

    This paper provides an overview on vitamins with inducing activities in plants, the molecular and cellular mechanisms implicated, and the hormonal signalling-network regulating this process. Moreover, it reports how vitamins might be part of the molecular events linked to induced resistance by the conventional elicitors. Induced resistance (IR), exploiting the plant innate-defense system is a sustainable strategy for plant disease control. In the last decade, vitamins have been proven to act as inducers of disease resistance, and these findings have received an important attention owing to their safety and cost effectiveness. Vitamins, including thiamine (TH, vitamin B1), riboflavin (RF, vitamin B2), menadione sodium bisulfite (MSB, vitamin K3), Para-aminobenzoic acid (PABA, vitamin Bx), and folic acid (FA, vitamin B9) provided an efficient protection against a wide range of pathogens through the modulation of specific host-defense facets. However, other vitamins, such as ascorbic acid (AA, vitamin C) and tocopherols (vitamin E), have been shown to be a part of the molecular mechanisms associated to IR. The present review is the first to summarize what vitamins are acting as inducers of disease resistance in plants and how could they be modulated by the conventional elicitors. Thus, this report provides an overview on the protective abilities of vitamins and the molecular and cellular mechanisms underlying their activities. Moreover, it describes the hormonal-signalling network regulating vitamin-signal transduction during IR. Finally, a biochemical model describing how vitamins are involved in the establishment of IR process is discussed.

  3. The utility of vitamin K3 (menadione) against pancreatic cancer.

    Science.gov (United States)

    Osada, Shinji; Tomita, Hiroyuki; Tanaka, Yoshihiro; Tokuyama, Yasuharu; Tanaka, Hidenori; Sakashita, Fumio; Takahashi, Takao

    2008-01-01

    To evaluate the efficacy of vitamin K3 (VK3) against pancreatic cancer, the molecular mechanism of VK3 or gemcitabine (GEM)-induced inhibition of proliferation was characterized. The cell viability was determined using the 3-[4,5-dimethylthiazol]-2,5-diphenyl tetrazolium bromide (MTT) test method. The expressions of cellular proteins were evaluated by Western blot analysis. For morphological studies of the in vivo transplanted cancer cells, the tissues were stained with hematoxylin and eosin. The IC50 of VK3 for pancreatic cancer cells was calculated for 42.1 +/- 3.5 microM. Western blot analysis showed that VK3 induced rapid phosphorylation of extracellular signal-regulated kinase (ERK) and c-Jun NH2-terminal kinase (JNK) 30 minutes after application. ERK but not JNK phosphorylation was maintained for at least 12 hours. Activation of apoptosis by VK3, as shown by molecular weight shifts of the pro-activated 32-kDa form of caspase-3 and poly(ADP-ribose)polymerase (PARP) cleavage of the 112-kDa form, was found. Treatment with the thiol antioxidant, L-cysteine (>0.2 mM), completely abrogated the VK3-induced phosphorylation of ERK, but not the JNK, and inhibition of proliferation. A caspase-3 inhibitor antagonized caspase-3 activation, but had no inhibitory effect on the proliferative activity of VK3. GEM at concentrations >0.1 microg/ml was found to inhibit cell proliferation after 24 hours. GEM also induced phosphorylation of JNK, activation of caspase-3 and accumulation of cyclin B1. Local application of VK3 was found to induce extensive tumor tissue necrosis, but slight hematemesis without necrosis was observed 48 hours after GEM injection. In Western blot, ERK but not JNK phosphorylation, was clearly detected in response to VK3 injection into the tumor tissue. The action of VK3 may lead to a favorable outcome against pancreatic cancer, and the detection of ERK phosphorylation in the tissue is important for predicting this effect.

  4. Pancultural self-enhancement.

    Science.gov (United States)

    Sedikides, Constantine; Gaertner, Lowell; Toguchi, Yoshiyasu

    2003-01-01

    The culture movement challenged the universality of the self-enhancement motive by proposing that the motive is pervasive in individualistic cultures (the West) but absent in collectivistic cultures (the East). The present research posited that Westerners and Easterners use different tactics to achieve the same goal: positive self-regard. Study 1 tested participants from differing cultural backgrounds (the United States vs. Japan), and Study 2 tested participants of differing self-construals (independent vs. interdependent). Americans and independents self-enhanced on individualistic attributes, whereas Japanese and interdependents self-enhanced on collectivistic attributes. Independents regarded individualistic attributes, whereas interdependents regarded collectivistic attributes, as personally important. Attribute importance mediated self-enhancement. Regardless of cultural background or self-construal, people self-enhance on personally important dimensions. Self-enhancement is a universal human motive.

  5. Enhancing operational safety

    Energy Technology Data Exchange (ETDEWEB)

    Wiebe, J S

    1997-09-01

    The presentation briefly considers the following aspects concerning enhancing operational safety of NPP: licensed control room supervision, reactivity changes, personnel access to control room, simulator training.

  6. EDITORIAL: Nano-enhanced! Nano-enhanced!

    Science.gov (United States)

    Demming, Anna

    2010-08-01

    In the early 19th century, a series of engineering and scientific breakthroughs by Nicolas Léonard Sadi Carnot, James Watt and many others led to the foundations of thermodynamics and a new pedigree of mechanical designs that reset the standards of engineering efficiency. The result was the industrial revolution. In optical- and electronics- based nanotechnology research, a similarly subtle bargain is being made; we cannot alter the fact that systems have a finite response to external excitations, but what we can do is enhance that response. The promising attributes of ZnO have long been recognised; its large band gap and high exciton binding energy lend it to a number of applications from laser diodes, LEDs, optical waveguides and switches, and acousto-optic applications to sun cream. When this material is grown into nanowires and nanorods, the material gains a whole new dimension, as quantum confinement effects come into play. Discovery of the enhanced radiative recombination, which has potential for exploitation in many optical and opto-electronic applications, drove intensive research into investigating these structures and into finding methods to synthesise them with optimised properties. This research revealed further subtleties in the properties of these materials. One example is the work by researchers in the US reporting synthesis procedures that produced a yield—defined as the weight ratio of ZnO nanowires to the original graphite flakes—of 200%, and which also demonstrated, through photoluminescence analysis of nanowires grown on graphite flakes and substrates, that graphite induces oxygen vacancies during annealing, which enhances the deep-level to near-band-edge emission ratio [1]. Other one-dimensional materials that provide field emission enhancements include carbon nanotubes, and work has been performed to find ways of optimising the emission efficiency from these structures, such as through control of the emitter density [2]. One of the

  7. Personal Identity in Enhancement

    Directory of Open Access Journals (Sweden)

    Jana Podroužková

    2015-09-01

    Full Text Available The aim of this paper is to introduce the concept of human enhancement, its methods and its relation to personal identity. Also several approaches to personal identity will be described. Transhumanism is a special think tank supporting human enhancement through modern technologies and some of its representatives claim, that even great changes to human organisms will not affect their personal identity. I will briefly describe the most important means of human enhancment and consider the problem of personal identity for each of them separately.

  8. Enhanced superconductivity of fullerenes

    Energy Technology Data Exchange (ETDEWEB)

    Washington, II, Aaron L.; Teprovich, Joseph A.; Zidan, Ragaiy

    2017-06-20

    Methods for enhancing characteristics of superconductive fullerenes and devices incorporating the fullerenes are disclosed. Enhancements can include increase in the critical transition temperature at a constant magnetic field; the existence of a superconducting hysteresis over a changing magnetic field; a decrease in the stabilizing magnetic field required for the onset of superconductivity; and/or an increase in the stability of superconductivity over a large magnetic field. The enhancements can be brought about by transmitting electromagnetic radiation to the superconductive fullerene such that the electromagnetic radiation impinges on the fullerene with an energy that is greater than the band gap of the fullerene.

  9. Enhancement of HHG yield

    International Nuclear Information System (INIS)

    Serrat, C.; Biegert, J.

    2011-01-01

    A static electric field periodically distributed in space controls and enhances the yield in high harmonic generation. The method is relatively simple to implement and allows tuning from the extreme-ultraviolet to soft X-ray. The radiation yield is selectively enhanced due to symmetry breaking induced by a static electric field on the interaction between the driving laser and the medium. The enhanced spectral region is tuned by varying the periodicity of the static electric field. Simulations predict an increase of more than two orders of magnitude for harmonics in the water window spectral range.

  10. Technology Enhanced Learning

    NARCIS (Netherlands)

    Klemke, Roland; Specht, Marcus

    2013-01-01

    Klemke, R., & Specht, M. (2013, 26-27 September). Technology Enhanced Learning. Presentation at the fourth international conference on eLearning (eLearning 2013), Belgrade, Serbia. http://econference.metropolitan.ac.rs/

  11. Rethinking enhancement in sport.

    Science.gov (United States)

    Miah, Andy

    2006-12-01

    This article explores the arguments surrounding the use of human enhancement technologies in sport, arguing for a reconceptualization of the doping debate. First, it develops an overview and critique of the legislative structures on enhancement. Subsequently, a conceptual framework for understanding the role of technological effects in sport is advanced. Finally, two case studies (hypoxic chambers and gene transfer) receive specific attention, through which it is argued that human enhancement technologies can enrich the practice of elite sports rather than diminish them. In conclusion, it is argued that elite sports are at a pivotal moment in their history as an increasing range of enhancements makes less relevant the protection of the natural human through anti-doping.

  12. Ogallala Bedrock Data Enhancement

    Data.gov (United States)

    Kansas Data Access and Support Center — This data set provides an enhanced estimate of the bedrock elevation of the Ogallala Aquifer in Kansas based on lithologic logs from a variety of sources. The data...

  13. Enhanced Magnetic Model 2015

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Enhanced Magnetic Model (EMM) extends to degree and order 720, resolving magnetic anomalies down to 56 km wavelength. The higher resolution of the EMM results in...

  14. Enhanced Magnetic Model 2010

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Enhanced Magnetic Model (EMM) extends to degree and order 720, resolving magnetic anomalies down to 56 km wavelength. The higher resolution of the EMM results in...

  15. Enhanced Use Leasing

    National Research Council Canada - National Science Library

    Vann-Olejasz, Sandra

    2002-01-01

    .... The term 'enhanced' was added as part of a 2001 amendment from Section 2812 of R.R. 5408, the Floyd D. Spence National Defense Authorization Act for Fiscal Year 2001 and enacted into Public Law 106-398...

  16. Plasmonic enhancement of electroluminescence

    Science.gov (United States)

    Guzatov, D. V.; Gaponenko, S. V.; Demir, H. V.

    2018-01-01

    Here plasmonic effect specifically on electroluminescence (EL) is studied in terms of radiative and nonradiative decay rates for a dipole near a metal spherical nanoparticle (NP). Contribution from scattering is taken into account and is shown to play a decisive role in EL enhancement owing to pronounced size-dependent radiative decay enhancement and weak size effect on non-radiative counterpart. Unlike photoluminescence where local incident field factor mainly determines the enhancement possibility and level, EL enhancement is only possible by means of quantum yield rise, EL enhancement being feasible only for an intrinsic quantum yield Q0 red-orange range only. Independently of positive effect on quantum yield, metal nanoparticles embedded in an electroluminescent device will improve its efficiency at high currents owing to enhanced overall recombination rate which will diminish manifestation of Auger processes. The latter are believed to be responsible for the known undesirable efficiency droop in semiconductor commercial quantum well based LEDs at higher current. For the same reason plasmonics can diminish quantum dot photodegradation from Auger process induced non-radiative recombination and photoionization thus opening a way to avoid negative Auger effects in emerging colloidal semiconductor LEDs.

  17. Mechanisms of Memory Enhancement

    Science.gov (United States)

    Stern, Sarah A.

    2012-01-01

    The ongoing quest for memory enhancement is one that grows necessary as the global population increasingly ages. The extraordinary progress that has been made in the past few decades elucidating the underlying mechanisms of how long-term memories are formed has provided insight into how memories might also be enhanced. Capitalizing on this knowledge, it has been postulated that targeting many of the same mechanisms, including CREB activation, AMPA/NMDA receptor trafficking, neuromodulation (e.g. via dopamine, adrenaline, cortisol or acetylcholine) and metabolic processes (e.g. via glucose and insulin) may all lead to the enhancement of memory. These and other mechanisms and/or approaches have been tested via genetic or pharmacological methods in animal models, and several have been investigated in humans as well. In addition, a number of behavioral methods, including exercise and reconsolidation, may also serve to strengthen and enhance memories. By capitalizing on this knowledge and continuing to investigate these promising avenues, memory enhancement may indeed be achieved in the future. PMID:23151999

  18. Human freedom and enhancement.

    Science.gov (United States)

    Heilinger, Jan-Christoph; Crone, Katja

    2014-02-01

    Ideas about freedom and related concepts like autonomy and self-determination play a prominent role in the moral debate about human enhancement interventions. However, there is not a single understanding of freedom available, and arguments referring to freedom are simultaneously used to argue both for and against enhancement interventions. This gives rise to misunderstandings and polemical arguments. The paper attempts to disentangle the different distinguishable concepts, classifies them and shows how they relate to one another in order to allow for a more structured and clearer debate. It concludes in identifying the individual underpinnings and the social conditions of choice and decision-making as particularly salient dimensions of freedom in the ethical debate about human enhancement.

  19. Enhancement and knowledge

    Directory of Open Access Journals (Sweden)

    Cinzia Talamo

    2012-04-01

    Full Text Available Many issues related to enhancement strategies emerge nowadays both from the scenario offered by public real estates and from the current processes of conveyance of public assets to local authorities. On one hand it is still difficult, from a strategic point of view, to approach in the medium-long term the chronic problems of the public estates due to deterioration, obsolescence and organizational inadequacy. On the other hand there is the risk that inadequate levels of knowledge lead on one side to a prevalence of the binomial enhancement-alienation and on the other side to a lack of full comprehension of the actual potentialities of the existing assets. In this direction it is possible to analyze the topic of enhancement through, among many, the key of knowledge during the lifecycle of a building.

  20. Defining Human Enhancement

    DEFF Research Database (Denmark)

    Nordberg, Ana

    2017-01-01

    -matter definitions are vital legal tools to determine what is currently regulated in established fields of law and whether there is room for a new legal field – Enhancement Law. This paper provides a reflection on the relevance of establishing a legal definition of human enhancement and to what extent different...... legal fields and jurisdictions may warrant different understandings of such concept. It reviews a number of different and often divergent concepts and taxonomies of human enhancement and concludes with the proposal and analysis of a definition: Use of technological means with the intention to improve......Emerging technologies open the prospect of extraordinary interventions on the human body. These may go beyond what is strictly necessary to sustain health and well-being. While responding to social and ethical challenges of such advances, the Law simultaneously faces the challenge of reflecting...

  1. Cavity-enhanced spectroscopies

    CERN Document Server

    van Zee, Roger

    2003-01-01

    ""Cavity-Enhanced Spectroscopy"" discusses the use of optical resonators and lasers to make sensitive spectroscopic measurements. This volume is written by the researcchers who pioneered these methods. The book reviews both the theory and practice behind these spectroscopic tools and discusses the scientific discoveries uncovered by these techniques. It begins with a chapter on the use of optical resonators for frequency stabilization of lasers, which is followed by in-depth chapters discussing cavity ring-down spectroscopy, frequency-modulated, cavity-enhanced spectroscopy, intracavity spectr

  2. Landscape encodings enhance optimization.

    Directory of Open Access Journals (Sweden)

    Konstantin Klemm

    Full Text Available Hard combinatorial optimization problems deal with the search for the minimum cost solutions (ground states of discrete systems under strong constraints. A transformation of state variables may enhance computational tractability. It has been argued that these state encodings are to be chosen invertible to retain the original size of the state space. Here we show how redundant non-invertible encodings enhance optimization by enriching the density of low-energy states. In addition, smooth landscapes may be established on encoded state spaces to guide local search dynamics towards the ground state.

  3. Low Vision Enhancement System

    Science.gov (United States)

    1995-01-01

    NASA's Technology Transfer Office at Stennis Space Center worked with the Johns Hopkins Wilmer Eye Institute in Baltimore, Md., to incorporate NASA software originally developed by NASA to process satellite images into the Low Vision Enhancement System (LVES). The LVES, referred to as 'ELVIS' by its users, is a portable image processing system that could make it possible to improve a person's vision by enhancing and altering images to compensate for impaired eyesight. The system consists of two orientation cameras, a zoom camera, and a video projection system. The headset and hand-held control weigh about two pounds each. Pictured is Jacob Webb, the first Mississippian to use the LVES.

  4. Biomedical enhancements as justice.

    Science.gov (United States)

    Nam, Jeesoo

    2015-02-01

    Biomedical enhancements, the applications of medical technology to make better those who are neither ill nor deficient, have made great strides in the past few decades. Using Amartya Sen's capability approach as my framework, I argue in this article that far from being simply permissible, we have a prima facie moral obligation to use these new developments for the end goal of promoting social justice. In terms of both range and magnitude, the use of biomedical enhancements will mark a radical advance in how we compensate the most disadvantaged members of society. © 2013 John Wiley & Sons Ltd.

  5. Landscape Encodings Enhance Optimization

    Science.gov (United States)

    Klemm, Konstantin; Mehta, Anita; Stadler, Peter F.

    2012-01-01

    Hard combinatorial optimization problems deal with the search for the minimum cost solutions (ground states) of discrete systems under strong constraints. A transformation of state variables may enhance computational tractability. It has been argued that these state encodings are to be chosen invertible to retain the original size of the state space. Here we show how redundant non-invertible encodings enhance optimization by enriching the density of low-energy states. In addition, smooth landscapes may be established on encoded state spaces to guide local search dynamics towards the ground state. PMID:22496860

  6. Enhanced Condensation Heat Transfer

    Science.gov (United States)

    Rose, John Winston

    The paper gives some personal observations on various aspects of enhanced condensation heat transfer. The topics discussed are external condensation (horizontal low-finned tubes and wire-wrapped tubes), internal condensation (microfin tubes and microchannels) and Marangoni condensation of binary mixtures.

  7. Heat transfer enhancement

    International Nuclear Information System (INIS)

    Hasatani, Masanobu; Itaya, Yoshinori

    1985-01-01

    In order to develop energy-saving techniques and new energy techniques, and also most advanced techniques by making industrial equipment with high performance, heat transfer performance frequently becomes an important problem. In addition, the improvement of conventional heat transfer techniques and the device of new heat transfer techniques are often required. It is most proper that chemical engineers engage in the research and development for enhancing heat transfer. The research and development for enhancing heat transfer are important to heighten heat exchange efficiency or to cool equipment for preventing overheat in high temperature heat transfer system. In this paper, the techniques of enhancing radiative heat transfer and the improvement of radiative heat transfer characteristics are reported. Radiative heat transfer is proportional to fourth power of absolute temperature, and it does not require any heat transfer medium, but efficient heat-radiation converters are necessary. As the techniques of enhancing radiative heat transfer, the increase of emission and absorption areas, the installation of emissive structures and the improvement of radiative characteristics are discussed. (Kako, I.)

  8. Teaching to Enhance Research

    Science.gov (United States)

    Harland, Tony

    2016-01-01

    In this paper, I present a conceptual argument for "teaching-led research" in which university lecturers construct courses that directly and positively influence their research, while at the same time, safeguard and enhance the student experience. A research-pedagogy for higher education considers the link between teaching and research,…

  9. Resonant enhancement in leptogenesis

    Science.gov (United States)

    Dev, P. S. B.; Garny, M.; Klaric, J.; Millington, P.; Teresi, D.

    2018-02-01

    Vanilla leptogenesis within the type I seesaw framework requires the mass scale of the right-handed neutrinos to be above 109 GeV. This lower bound can be avoided if at least two of the sterile states are almost mass degenerate, which leads to an enhancement of the decay asymmetry. Leptogenesis models that can be tested in current and upcoming experiments often rely on this resonant enhancement, and a systematic and consistent description is therefore necessary for phenomenological applications. In this paper, we give an overview of different methods that have been used to study the saturation of the resonant enhancement when the mass difference becomes comparable to the characteristic width of the Majorana neutrinos. In this limit, coherent flavor transitions start to play a decisive role, and off-diagonal correlations in flavor space have to be taken into account. We compare various formalisms that have been used to describe the resonant regime and discuss under which circumstances the resonant enhancement can be captured by simplified expressions for the CP asymmetry. Finally, we briefly review some of the phenomenological aspects of resonant leptogenesis.

  10. Enhancing learning with technology

    NARCIS (Netherlands)

    Specht, Marcus; Klemke, Roland

    2013-01-01

    Specht, M., & Klemke, R. (2013, 26-27 September). Enhancing Learning with Technology. In D. Milosevic (Ed.), Proceedings of the fourth international conference on eLearning (eLearning 2013) (pp. 37-45). Belgrade Metropolitan University, Belgrade, Serbia. http://econference.metropolitan.ac.rs/

  11. Placebo can enhance creativity.

    Science.gov (United States)

    Rozenkrantz, Liron; Mayo, Avraham E; Ilan, Tomer; Hart, Yuval; Noy, Lior; Alon, Uri

    2017-01-01

    The placebo effect is usually studied in clinical settings for decreasing negative symptoms such as pain, depression and anxiety. There is interest in exploring the placebo effect also outside the clinic, for enhancing positive aspects of performance or cognition. Several studies indicate that placebo can enhance cognitive abilities including memory, implicit learning and general knowledge. Here, we ask whether placebo can enhance creativity, an important aspect of human cognition. Subjects were randomly assigned to a control group who smelled and rated an odorant (n = 45), and a placebo group who were treated identically but were also told that the odorant increases creativity and reduces inhibitions (n = 45). Subjects completed a recently developed automated test for creativity, the creative foraging game (CFG), and a randomly chosen subset (n = 57) also completed two manual standardized creativity tests, the alternate uses test (AUT) and the Torrance test (TTCT). In all three tests, participants were asked to create as many original solutions and were scored for originality, flexibility and fluency. The placebo group showed higher originality than the control group both in the CFG (pcreativity. This strengthens the view that placebo can be used not only to reduce negative clinical symptoms, but also to enhance positive aspects of cognition. Furthermore, we find that the impact of placebo on creativity can be tested by CFG, which can quantify multiple aspects of creative search without need for manual coding. This approach opens the way to explore the behavioral and neural mechanisms by which placebo might amplify creativity.

  12. Music Enhances Learning.

    Science.gov (United States)

    Campabello, Nicolette; De Carlo, Mary Jane; O'Neil, Jean; Vacek, Mary Jill

    An action research project implemented musical strategies to affect and enhance student recall and memory. The target population was three suburban elementary schools near a major midwestern city: (1) a kindergarten classroom contained 32-38 students; (2) a second grade classroom contained 23 students and five Individualized Education Program…

  13. Medically-enhanced normality

    DEFF Research Database (Denmark)

    Møldrup, Claus; Traulsen, Janine Morgall; Almarsdóttir, Anna Birna

    2003-01-01

    Objective: To consider public perspectives on the use of medicines for non-medical purposes, a usage called medically-enhanced normality (MEN). Method: Examples from the literature were combined with empirical data derived from two Danish research projects: a Delphi internet study and a Telebus...

  14. Enhanced processive cellulases

    Science.gov (United States)

    Adney, William S.; Beckham, Gregg T.; Jarvis, Eric; Himmel, Michael E.; Decker, Stephen R.; Linger, Jeffrey G.; Podkaminer, Kara; Baker, John O.; Taylor, II, Larry; Xu, Qi; Singh, Arjun

    2017-06-20

    Nucleic acid sequences encoding chimeric polypeptides that exhibit enhanced cellulase activities are disclosed herein. These nucleic acids may be expressed in hosts such as fungi, which in turn may be cultured to produce chimeric polypeptides. Also disclosed are chimeric polypeptides and their use in the degradation of cellulosic materials.

  15. Enhanced Microfluidic Electromagnetic Measurements

    Science.gov (United States)

    Giovangrandi, Laurent (Inventor); Ricco, Antonio J. (Inventor); Kovacs, Gregory (Inventor)

    2015-01-01

    Techniques for enhanced microfluidic impedance spectroscopy include causing a core fluid to flow into a channel between two sheath flows of one or more sheath fluids different from the core fluid. Flow in the channel is laminar. A dielectric constant of a fluid constituting either sheath flow is much less than a dielectric constant of the core fluid. Electrical impedance is measured in the channel between at least a first pair of electrodes. In some embodiments, enhanced optical measurements include causing a core fluid to flow into a channel between two sheath flows of one or more sheath fluids different from the core fluid. An optical index of refraction of a fluid constituting either sheath flow is much less than an optical index of refraction of the core fluid. An optical property is measured in the channel.

  16. Superposition Enhanced Nested Sampling

    Directory of Open Access Journals (Sweden)

    Stefano Martiniani

    2014-08-01

    Full Text Available The theoretical analysis of many problems in physics, astronomy, and applied mathematics requires an efficient numerical exploration of multimodal parameter spaces that exhibit broken ergodicity. Monte Carlo methods are widely used to deal with these classes of problems, but such simulations suffer from a ubiquitous sampling problem: The probability of sampling a particular state is proportional to its entropic weight. Devising an algorithm capable of sampling efficiently the full phase space is a long-standing problem. Here, we report a new hybrid method for the exploration of multimodal parameter spaces exhibiting broken ergodicity. Superposition enhanced nested sampling combines the strengths of global optimization with the unbiased or athermal sampling of nested sampling, greatly enhancing its efficiency with no additional parameters. We report extensive tests of this new approach for atomic clusters that are known to have energy landscapes for which conventional sampling schemes suffer from broken ergodicity. We also introduce a novel parallelization algorithm for nested sampling.

  17. Enhancing radiation biodosimetry capability

    International Nuclear Information System (INIS)

    Alok, A.; Kumar, A.; Kulshrestra, S.; Choudhary, S.; Bhagi, S.; Adhikari, J.S.; Chaudhury, N.K.

    2016-01-01

    Biodosimetry laboratories are necessary for quick and accurate assessment of absorbed radiation dose in suspected individuals for their medical management. The method is based on dicentric chromosomal assay (Gold standard). This assay is completely manual and time consuming, require skill and competency of laboratory staff. There is a necessity of more biodosimetry labs within country and networking within and at international level for enhancing medical preparedness for management of radiation emergency

  18. Texture Enhanced Appearance Models

    DEFF Research Database (Denmark)

    Larsen, Rasmus; Stegmann, Mikkel Bille; Darkner, Sune

    2007-01-01

    Statistical region-based registration methods such as the Active Appearance Model (AAM) are used for establishing dense correspondences in images. At low resolution, images correspondences can be recovered reliably in real-time. However, as resolution increases this becomes infeasible due...... representation are superior to wavelet representations at high dimensionality-reduction rates. At low reduction rates an edge enhanced wavelet representation provides better segmentation accuracy than the full standard AAM model....

  19. Semantically Enhanced Recommender Systems

    Science.gov (United States)

    Ruiz-Montiel, Manuela; Aldana-Montes, José F.

    Recommender Systems have become a significant area in the context of web personalization, given the large amount of available data. Ontologies can be widely taken advantage of in recommender systems, since they provide a means of classifying and discovering of new information about the items to recommend, about user profiles and even about their context. We have developed a semantically enhanced recommender system based on this kind of ontologies. In this paper we present a description of the proposed system.

  20. Novelty enhances visual perception.

    Directory of Open Access Journals (Sweden)

    Judith Schomaker

    Full Text Available The effects of novelty on low-level visual perception were investigated in two experiments using a two-alternative forced-choice tilt detection task. A target, consisting of a Gabor patch, was preceded by a cue that was either a novel or a familiar fractal image. Participants had to indicate whether the Gabor stimulus was vertically oriented or slightly tilted. In the first experiment tilt angle was manipulated; in the second contrast of the Gabor patch was varied. In the first, we found that sensitivity was enhanced after a novel compared to a familiar cue, and in the second we found sensitivity to be enhanced for novel cues in later experimental blocks when participants became more and more familiarized with the familiar cue. These effects were not caused by a shift in the response criterion. This shows for the first time that novel stimuli affect low-level characteristics of perception. We suggest that novelty can elicit a transient attentional response, thereby enhancing perception.

  1. Novelty enhances visual perception.

    Science.gov (United States)

    Schomaker, Judith; Meeter, Martijn

    2012-01-01

    The effects of novelty on low-level visual perception were investigated in two experiments using a two-alternative forced-choice tilt detection task. A target, consisting of a Gabor patch, was preceded by a cue that was either a novel or a familiar fractal image. Participants had to indicate whether the Gabor stimulus was vertically oriented or slightly tilted. In the first experiment tilt angle was manipulated; in the second contrast of the Gabor patch was varied. In the first, we found that sensitivity was enhanced after a novel compared to a familiar cue, and in the second we found sensitivity to be enhanced for novel cues in later experimental blocks when participants became more and more familiarized with the familiar cue. These effects were not caused by a shift in the response criterion. This shows for the first time that novel stimuli affect low-level characteristics of perception. We suggest that novelty can elicit a transient attentional response, thereby enhancing perception.

  2. ICRF enhanced potentials

    International Nuclear Information System (INIS)

    Nelson, B.A.

    1987-01-01

    Ion-confining potentials in the Phaedrus tandem mirror are shown to be enhanced over Boltzmann-relations predicted values by radio-frequency (rf) waves in the ion cyclotron range of frequencies (ICRF). The ICRF enhanced potential is larger in the end cell with a lower passing density. Peak potential values decrease with increasing ion endloss current (or central cell density) for a constant rf capacitor bank voltage, and increase with increasing rf-capacitor bank voltage, for a constant ion endloss value (or central cell density). In fully axisymmetric operation, a potential peak is produced in an end cell by the central-cell rf, (with-out end-cell rf) and is found only in the end cell nearer the central-cell antenna. ICRF enhanced potentials are explained as an equilibrium between the electron-collisional filling-in rate and the electron pumping out rate provided by axial time-varying electric fields. Thermal barrier-like potential structures were found in the transition regions between the central cell and end cells, in the fully axisymmetric Phaedrus. Central-cell ICRF trapping effects combined with end-cell μΔ B forces create and pump the barrier potential wells

  3. Sleep for cognitive enhancement

    Directory of Open Access Journals (Sweden)

    Susanne eDiekelmann

    2014-04-01

    Full Text Available Sleep is essential for effective cognitive functioning. Loosing even a few hours of sleep can have detrimental effects on a wide variety of cognitive processes such as attention, language, reasoning, decision making, learning and memory. While sleep is necessary to ensure normal healthy cognitive functioning, it can also enhance performance beyond the boundaries of the normal condition. This article discusses the enhancing potential of sleep, mainly focusing on the domain of learning and memory. Sleep is known to facilitate the consolidation of memories learned before sleep as well as the acquisition of new memories to be learned after sleep. According to a widely held model this beneficial effect of sleep relies on the neuronal reactivation of memories during sleep that is associated with sleep-specific brain oscillations (slow oscillations, spindles, ripples as well as a characteristic neurotransmitter milieu. Recent research indicates that memory processing during sleep can be boosted by (i cueing memory reactivation during sleep, (ii stimulating sleep-specific brain oscillations, and (iii targeting specific neurotransmitter systems pharmacologically. Olfactory and auditory cues can be used, for example, to increase reactivation of associated memories during post-learning sleep. Intensifying neocortical slow oscillations (the hallmark of slow wave sleep by electrical or auditory stimulation and modulating specific neurotransmitters such as noradrenaline and glutamate likewise facilitates memory processing during sleep. With this evidence in mind, this article concludes by discussing different methodological caveats and ethical issues that should be considered when thinking about using sleep for cognitive enhancement in everyday applications.

  4. Placebo can enhance creativity.

    Directory of Open Access Journals (Sweden)

    Liron Rozenkrantz

    Full Text Available The placebo effect is usually studied in clinical settings for decreasing negative symptoms such as pain, depression and anxiety. There is interest in exploring the placebo effect also outside the clinic, for enhancing positive aspects of performance or cognition. Several studies indicate that placebo can enhance cognitive abilities including memory, implicit learning and general knowledge. Here, we ask whether placebo can enhance creativity, an important aspect of human cognition.Subjects were randomly assigned to a control group who smelled and rated an odorant (n = 45, and a placebo group who were treated identically but were also told that the odorant increases creativity and reduces inhibitions (n = 45. Subjects completed a recently developed automated test for creativity, the creative foraging game (CFG, and a randomly chosen subset (n = 57 also completed two manual standardized creativity tests, the alternate uses test (AUT and the Torrance test (TTCT. In all three tests, participants were asked to create as many original solutions and were scored for originality, flexibility and fluency.The placebo group showed higher originality than the control group both in the CFG (p<0.04, effect size = 0.5 and in the AUT (p<0.05, effect size = 0.4, but not in the Torrance test. The placebo group also found more shapes outside of the standard categories found by a set of 100 CFG players in a previous study, a feature termed out-of-the-boxness (p<0.01, effect size = 0.6.The findings indicate that placebo can enhance the originality aspect of creativity. This strengthens the view that placebo can be used not only to reduce negative clinical symptoms, but also to enhance positive aspects of cognition. Furthermore, we find that the impact of placebo on creativity can be tested by CFG, which can quantify multiple aspects of creative search without need for manual coding. This approach opens the way to explore the behavioral and neural mechanisms by which

  5. Enhancing LAN performance

    CERN Document Server

    Held, Gilbert

    2004-01-01

    Enhancing LAN Performance, Fourth Edition explains how to connect geographically separated LANs with appropriate bandwidth, the issues to consider when weighing the use of multiport or dualport devices, how to estimate traffic for new networks, the effects of configuration changes on the performance of Ethernet and Token Ring networks, the design of switch-based networks that prevent traffic bottlenecks, and other critical topics. It provides the tools to address these issues in relation to specific network requirements. This volume develops mathematical models of various LAN performance issue

  6. Enhanced CANDU 6 Reactor

    International Nuclear Information System (INIS)

    Azeez, S.; Alizadeh, A.; Girouard, P.

    2005-01-01

    Full text: The CANDU 6 power reactor is visionary in its approach, remarkable for its on-power refuelling capability and proven over years of safe, economical and reliable power production. Developed by Atomic Energy of Canada Ltd, the CANDU 6 design offers excellent performance utilizing state-of-the-art technology. The first CANDU 6 plants went into service in the early 1980's as leading edge technology and the design has been continuously advanced to maintain superior performance with an outstanding safety record. The first CANDU 6 plants- Gentilly 2 and Point Lepreau in Canada, Embalse in Argentina and Wolsong- Unit 1 in Korea have been in service for more than 21 years and are still producing electricity at peak performance and to the end of 2004, their average lifetime Capacity Factor was 83.2%. The newer CANDU 6 units in Romania (Cernavoda 1), Korea (Wolsong-Units 2, 3 and 4) and Qinshan (Phase III- Units 1 and 2) have also been performing at outstanding levels. The average lifetime Capacity Factor of the 10 CANDU 6 operating units around the world has been 87% to the end of 2004. Building on these successes, AECL is committed to the further development of this highly successful design, now focussing on meeting customer's needs for reduced costs, further improvements to plant operation and performance, enhanced safety and incorporating up-to-date technology as warranted. This has resulted in AECL embarking on improving the CANDU 6 design through an upgraded product termed as the 'Enhanced CANDU 6' (EC6)- which incorporates several attractive but proven features that will make the CANDU 6 reactor even more economical, safer and easier to operate. Some of the key features that will be incorporated in the EC6 include increasing the plant's power output, shortening the overall project schedule, decreasing the capital cost, dealing with obsolescence issues, optimizing maintenance outages and incorporating lessons learnt through feedback obtained from the

  7. Wedgelet Enhanced Appearance Models

    DEFF Research Database (Denmark)

    Darkner, Sune; Larsen, Rasmus; Stegmann, Mikkel Bille

    2004-01-01

    Statistical region-based segmentation methods such as the Active Appearance Model (AAM) are used for establishing dense correspondences in images based on learning the variation in shape and pixel intensities in a training set. For low resolution 2D images correspondences can be recovered reliably....... The wedgelet regression trees employed are based on triangular domains and estimated using cross validation. The wedgelet regression trees are functional descriptions of the intensity information and serve to 1) reduce noise and 2) produce a compact textural description. The wedgelet enhanced appearance model...

  8. ICT Enhanced Buildings Potentials

    DEFF Research Database (Denmark)

    Christiansson, Per

    2007-01-01

    component systems that are accessed and integrated in the real world of building use in different contexts. The ICT systems may be physically or virtually embedded in the building. Already in 1982 AT&T established the 'intelligent buildings', IB, concept due to marketing reasons and the Informart building...... with focus on virtual building models support, new services and user environment definitions and development, virtual spaces and augmented reality, intelligent building components, application ontologies, and ICT systems integration to illustrate ICT enhanced buildings potentials and R&D needs.  ...

  9. Enhanced by Frost

    Science.gov (United States)

    2005-01-01

    30 September 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows outcrops of south polar layered terrain. Their appearance in this July 2005 springtime image is enhanced by bright patches of carbon dioxide frost. The frost is left over from the previous southern winter season; by summer, the frost would be gone. Location near: 84.6oS, 203.5oW Image width: width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Spring

  10. The perils of moral enhancement

    Directory of Open Access Journals (Sweden)

    Dobrijević Aleksandar

    2012-01-01

    Full Text Available The idea of biotechnological enhancement of people for non-medical purposes is not unambiguous. A gap that may arise between the “cognitive” and so-called “moral” enhancement points precisely to this fact. This article shows that, contrary to the intentions of its supporters, the idea according to which moral enhancement has precedence over cognitive enhancement is essentially just a new form of undermining human freedom. [Projekat Ministarstva nauke Republike Srbije, br. 41004

  11. Acoustically enhanced heat transport

    Energy Technology Data Exchange (ETDEWEB)

    Ang, Kar M.; Hung, Yew Mun; Tan, Ming K., E-mail: tan.ming.kwang@monash.edu [School of Engineering, Monash University Malaysia, 47500 Bandar Sunway, Selangor (Malaysia); Yeo, Leslie Y. [Micro/Nanophysics Research Laboratory, RMIT University, Melbourne, VIC 3001 (Australia); Friend, James R. [Department of Mechanical and Aerospace Engineering, University of California, San Diego, California 92093 (United States)

    2016-01-15

    We investigate the enhancement of heat transfer in the nucleate boiling regime by inducing high frequency acoustic waves (f ∼ 10{sup 6} Hz) on the heated surface. In the experiments, liquid droplets (deionized water) are dispensed directly onto a heated, vibrating substrate. At lower vibration amplitudes (ξ{sub s} ∼ 10{sup −9} m), the improved heat transfer is mainly due to the detachment of vapor bubbles from the heated surface and the induced thermal mixing. Upon increasing the vibration amplitude (ξ{sub s} ∼ 10{sup −8} m), the heat transfer becomes more substantial due to the rapid bursting of vapor bubbles happening at the liquid-air interface as a consequence of capillary waves travelling in the thin liquid film between the vapor bubble and the air. Further increases then lead to rapid atomization that continues to enhance the heat transfer. An acoustic wave displacement amplitude on the order of 10{sup −8} m with 10{sup 6} Hz order frequencies is observed to produce an improvement of up to 50% reduction in the surface temperature over the case without acoustic excitation.

  12. Diablo Canyon ECCS enhancements

    International Nuclear Information System (INIS)

    Lin, A.; Lee, T.P.; Walter, L.E.

    2004-01-01

    Diablo Canyon Power Plant (DCPP) operated by Pacific Gas and Electric Co. (PG and E) is a Westinghouse designed four loop plant. In recent years, several issues were identified regarding the compliance of the Emergency Core Cooling System (ECCS) surveillance tests to the ECCS analyses assumptions. These concerns are related mostly to the High Head Safety Injection (HHSI) and the Intermediate Head Safety Injection (IHSI) systems where the injection line throttle valves are adjusted during outage surveillance testing to ensure compliance with the Technical Specifications (TS). To resolve all of the identified issues PG and E performed an ECCS reanalysis and upgraded the ECCS surveillance test program and also had Westinghouse perform a containment reanalysis using their latest model. As a result of these plant specific enhancement efforts, DCPP widened the operating window for TS surveillance testing, lowered the ECCS pumps' acceptance performance curves, and re-gained Peak Clad Temperature (PCT) and containment peak pressure margins. These enhancements are generically applicable to other plants and are addressed in this paper. (author)

  13. Biomass energy resource enhancement

    Energy Technology Data Exchange (ETDEWEB)

    Grover, P D [Indian Institute of Technology, New Delhi (India)

    1995-12-01

    The demand for energy in developing countries is expected to increase to at least three times its present level within the next 25 years. If this demand is to be met by fossil fuels, an additional 2 billion tonnes of crude oil or 3 billion tonnes of coal would be needed every year. This consumption pattern, if allowed to proceed, would add 10 billion tonnes of CO{sub 2}, to the global atmosphere each year, with its attendant risk of global warming. Therefore, just for our survival, it is imperative to progressively replace fossil fuels by biomass energy resources and to enhance the efficiency of use of the latter. Biomass is not only environmentally benign but is also abundant. It is being photosynthesised at the rate of 200 billion tonnes of carbon every year, which is equivalent to 10 times the world`s present demand for energy. Presently, biomass energy resources are highly under-utilised in developing countries; when they are used it is through combustion, which is inefficient and causes widespread environmental pollution with its associated health hazards. Owing to the low bulk density and high moisture content of biomass, which make it difficult to collect, transport and store, as well as its ash-related thermochemical properties, its biodegradability and seasonal availability, the industrial use of biomass is limited to small and (some) medium-scale industries, most of which are unable to afford efficient but often costly energy conversion systems. Considering these constraints and the need to enhance the use base, biomass energy technologies appropriate to developing countries have been identified. Technologies such as briquetting and densification to upgrade biomass fuels are being adopted as conventional measures in some developing countries. The biomass energy base can be enhanced only once these technologies have been shown to be viable under local conditions and with local raw materials, after which they will multiply on their own, as has been the case

  14. Biomass energy resource enhancement

    International Nuclear Information System (INIS)

    Grover, P.D.

    1995-01-01

    The demand for energy in developing countries is expected to increase to at least three times its present level within the next 25 years. If this demand is to be met by fossil fuels, an additional 2 billion tonnes of crude oil or 3 billion tonnes of coal would be needed every year. This consumption pattern, if allowed to proceed, would add 10 billion tonnes of CO 2 , to the global atmosphere each year, with its attendant risk of global warming. Therefore, just for our survival, it is imperative to progressively replace fossil fuels by biomass energy resources and to enhance the efficiency of use of the latter. Biomass is not only environmentally benign but is also abundant. It is being photosynthesised at the rate of 200 billion tonnes of carbon every year, which is equivalent to 10 times the world's present demand for energy. Presently, biomass energy resources are highly under-utilised in developing countries; when they are used it is through combustion, which is inefficient and causes widespread environmental pollution with its associated health hazards. Owing to the low bulk density and high moisture content of biomass, which make it difficult to collect, transport and store, as well as its ash-related thermochemical properties, its biodegradability and seasonal availability, the industrial use of biomass is limited to small and (some) medium-scale industries, most of which are unable to afford efficient but often costly energy conversion systems. Considering these constraints and the need to enhance the use base, biomass energy technologies appropriate to developing countries have been identified. Technologies such as briquetting and densification to upgrade biomass fuels are being adopted as conventional measures in some developing countries. The biomass energy base can be enhanced only once these technologies have been shown to be viable under local conditions and with local raw materials, after which they will multiply on their own, as has been the case

  15. Novel medical image enhancement algorithms

    Science.gov (United States)

    Agaian, Sos; McClendon, Stephen A.

    2010-01-01

    In this paper, we present two novel medical image enhancement algorithms. The first, a global image enhancement algorithm, utilizes an alpha-trimmed mean filter as its backbone to sharpen images. The second algorithm uses a cascaded unsharp masking technique to separate the high frequency components of an image in order for them to be enhanced using a modified adaptive contrast enhancement algorithm. Experimental results from enhancing electron microscopy, radiological, CT scan and MRI scan images, using the MATLAB environment, are then compared to the original images as well as other enhancement methods, such as histogram equalization and two forms of adaptive contrast enhancement. An image processing scheme for electron microscopy images of Purkinje cells will also be implemented and utilized as a comparison tool to evaluate the performance of our algorithm.

  16. Quantum enhanced optical sensing

    DEFF Research Database (Denmark)

    Schäfermeier, Clemens

    light source was designed and built from scratch, which achieved a noise suppression of −8 dB at an optical pump power of 40mW. The generated squeezed light was first used to demonstrate how Gaussian states and detection can beat the shot noise limit and Rayleigh criterion in phase measurements...... or demanding detection techniques. A second experiment combined squeezed light and feedback control to cool an optomechanical system. This proof-of-principle study is the first reported squeezing enhanced optomechanical cooling experiment. Despite losses of more than 50% (a resulting noise suppression of −2 d...... signals to overcome e.g. technical detection limitations. Amplified communication channels were characterised by applying the measure of mutual information I, as it offers strict bounds on the maximum achievable performance, which enabled a fair comparison between different applications scenarios...

  17. Teacher Enhancement Institute

    Science.gov (United States)

    Marshall-Bradley, Tina

    1994-01-01

    During the 1980's, a period of intense concern over educational quality in the United States, few indicators of U.S. student achievement garnered the interest of policy makers and pundits as successfully as the results of international testing in mathematics and science. This concern was so great that as a part of the Goals 2000 initiative, President George Bush indicated that 'By the year 2000, U.S. students should be first in the world in mathematics and science.' The Clinton Administration is placing a major emphasis, not only on rigorous academic standards and creating a new system for assessing students' progress, but also including professional development as a major focus. The argument being that teachers need more sustained, intensive training to prepare them to teach to higher standards. Executive order 12821 mandates that national laboratories 'assist in the mathematics and science education of our Nation's students, teachers, parents and the public by establishing programs at their agency to provide for training elementary and secondary school teachers to improve their knowledge of mathematics and science'. These and other issues led to the development of ideas for a project that addresses the need for excellence in mathematics, science and technology instruction. In response to these initiatives the NASA/LaRC Teacher Enhancement Institute was proposed. The TEI incorporated systemic reform perspectives, enhanced content knowledge for teachers, and teacher preparation. Emphasis was also placed on recruiting those educators who teach in impoverished urban school districts with at-risk student populations who have been traditionally under represented in science, mathematics, technology and engineering. Participants in the Teacher Enhancement Institute were 37 teachers from grades K-8, teaching in Region 2 in the state of Virginia, as well as 2 preservice teachers from Norfolk State University and one teacher from Dublin, Virginia, where a Science

  18. Photon enhanced thermionic emission

    Science.gov (United States)

    Schwede, Jared; Melosh, Nicholas; Shen, Zhixun

    2014-10-07

    Photon Enhanced Thermionic Emission (PETE) is exploited to provide improved efficiency for radiant energy conversion. A hot (greater than 200.degree. C.) semiconductor cathode is illuminated such that it emits electrons. Because the cathode is hot, significantly more electrons are emitted than would be emitted from a room temperature (or colder) cathode under the same illumination conditions. As a result of this increased electron emission, the energy conversion efficiency can be significantly increased relative to a conventional photovoltaic device. In PETE, the cathode electrons can be (and typically are) thermalized with respect to the cathode. As a result, PETE does not rely on emission of non-thermalized electrons, and is significantly easier to implement than hot-carrier emission approaches.

  19. Enhancing biological nitrogen fixation

    Energy Technology Data Exchange (ETDEWEB)

    Danso, S.K.A.; Eskew, D.L. (Joint FAO/IAEA Div. of Isotope and Radiation Applications of Atomic Energy for Food and Agricultural Development, Vienna (Austria))

    1984-06-01

    Several co-ordinated research programmes (CRPs) conducted by the Soil Fertility, Irrigation and Crop Production Section of the Joint FAO/IAEA Division have concentrated on finding the most efficient way of applying nitrogen fertilizers to various crops, using nitrogen-15 (/sup 15/N) as a tracer. The findings of these studies have been adopted in many countries around the world, resulting in savings of nitrogen fertilizers worth many millions of dollars every year. More recently, the Section's CRPs have focused on enhancing the natural process of biological di-nitrogen fixation. The /sup 15/N isotope technique has proven to be very valuable in studies of the legume-Rhizobium symbiosis, allowing many more experiments than before to be done and yielding much new practical information. The Soils Section is now working to extend the use of the technique to other nitrogen-fixing symbioses.

  20. Surface enhanced thermo lithography

    KAUST Repository

    Coluccio, Maria Laura

    2017-01-13

    We used electroless deposition to fabricate clusters of silver nanoparticles (NPs) on a silicon substrate. These clusters are plasmonics devices that induce giant electromagnetic (EM) field increments. When those EM field are absorbed by the metal NPs clusters generate, in turn, severe temperature increases. Here, we used the laser radiation of a conventional Raman set-up to transfer geometrical patterns from a template of metal NPs clusters into a layer of thermo sensitive Polyphthalaldehyde (PPA) polymer. Temperature profile on the devices depends on specific arrangements of silver nanoparticles. In plane temperature variations may be controlled with (i) high nano-meter spatial precision and (ii) single Kelvin temperature resolution on varying the shape, size and spacing of metal nanostructures. This scheme can be used to generate strongly localized heat amplifications for applications in nanotechnology, surface enhanced thermo-lithography (SETL), biology and medicine (for space resolved cell ablation and treatment), nano-chemistry.

  1. Transformer ratio enhancement experiment

    International Nuclear Information System (INIS)

    Gai, W.; Power, J. G.; Kanareykin, A.; Neasheva, E.; Altmark, A.

    2004-01-01

    Recently, a multibunch scheme for efficient acceleration based on dielectric wakefield accelerator technology was outlined in J.G. Power, W. Gai, A. Kanareykin, X. Sun. PAC 2001 Proceedings, pp. 114-116, 2002. In this paper we present an experimental program for the design, development and demonstration of an Enhanced Transformer Ratio Dielectric Wakefield Accelerator (ETR-DWA). The principal goal is to increase the transformer ratio R, the parameter that characterizes the energy transfer efficiency from the accelerating structure to the accelerated electron beam. We present here an experimental design of a 13.625 GHz dielectric loaded accelerating structure, a laser multisplitter producing a ramped bunch train, and simulations of the bunch train parameters required. Experimental results of the accelerating structure bench testing and ramped pulsed train generation with the laser multisplitter are shown as well. Using beam dynamic simulations, we also obtain the focusing FODO lattice parameters

  2. Enhanced oil recovery system

    Science.gov (United States)

    Goldsberry, Fred L.

    1989-01-01

    All energy resources available from a geopressured geothermal reservoir are used for the production of pipeline quality gas using a high pressure separator/heat exchanger and a membrane separator, and recovering waste gas from both the membrane separator and a low pressure separator in tandem with the high pressure separator for use in enhanced oil recovery, or in powering a gas engine and turbine set. Liquid hydrocarbons are skimmed off the top of geothermal brine in the low pressure separator. High pressure brine from the geothermal well is used to drive a turbine/generator set before recovering waste gas in the first separator. Another turbine/generator set is provided in a supercritical binary power plant that uses propane as a working fluid in a closed cycle, and uses exhaust heat from the combustion engine and geothermal energy of the brine in the separator/heat exchanger to heat the propane.

  3. Surface enhanced Raman scattering

    CERN Document Server

    Furtak, Thomas

    1982-01-01

    In the course of the development of surface science, advances have been identified with the introduction of new diagnostic probes for analytical characterization of the adsorbates and microscopic structure of surfaces and interfaces. Among the most recently de­ veloped techniques, and one around which a storm of controversy has developed, is what has now been earmarked as surface enhanced Raman scattering (SERS). Within this phenomenon, molecules adsorbed onto metal surfaces under certain conditions exhibit an anomalously large interaction cross section for the Raman effect. This makes it possible to observe the detailed vibrational signature of the adsorbate in the ambient phase with an energy resolution much higher than that which is presently available in electron energy loss spectroscopy and when the surface is in contact with a much larger amount of material than that which can be tolerated in infrared absorption experiments. The ability to perform vibrational spectroscopy under these conditions would l...

  4. Surface enhanced thermo lithography

    KAUST Repository

    Coluccio, Maria Laura; Alabastri, Alessandro; Bonanni, Simon; Majewska, Roksana; Dattoli, Elisabetta; Barberio, Marianna; Candeloro, Patrizio; Perozziello, Gerardo; Mollace, Vincenzo; Di Fabrizio, Enzo M.; Gentile, Francesco

    2017-01-01

    We used electroless deposition to fabricate clusters of silver nanoparticles (NPs) on a silicon substrate. These clusters are plasmonics devices that induce giant electromagnetic (EM) field increments. When those EM field are absorbed by the metal NPs clusters generate, in turn, severe temperature increases. Here, we used the laser radiation of a conventional Raman set-up to transfer geometrical patterns from a template of metal NPs clusters into a layer of thermo sensitive Polyphthalaldehyde (PPA) polymer. Temperature profile on the devices depends on specific arrangements of silver nanoparticles. In plane temperature variations may be controlled with (i) high nano-meter spatial precision and (ii) single Kelvin temperature resolution on varying the shape, size and spacing of metal nanostructures. This scheme can be used to generate strongly localized heat amplifications for applications in nanotechnology, surface enhanced thermo-lithography (SETL), biology and medicine (for space resolved cell ablation and treatment), nano-chemistry.

  5. Enhanced Geothermal Systems

    Energy Technology Data Exchange (ETDEWEB)

    Jeanloz, R. [The MITRE Corporation, McLean, VA (United States); Stone, H. [The MITRE Corporation, McLean, VA (United States); et al.

    2013-12-31

    DOE, through the Geothermal Technologies Office (GTO) within the Office of Energy Efficiency and Renewable Energy, requested this study, identifying a focus on: i) assessment of technologies and approaches for subsurface imaging and characterization so as to be able to validate EGS opportunities, and ii) assessment of approaches toward creating sites for EGS, including science and engineering to enhance permeability and increase the recovery factor. Two days of briefings provided in-depth discussion of a wide range of themes and challenges in EGS, and represented perspectives from industry, government laboratories and university researchers. JASON also contacted colleagues from universities, government labs and industry in further conversations to learn the state of the field and potential technologies relevant to EGS.

  6. Noise Enhanced Stability

    International Nuclear Information System (INIS)

    Spagnolo, B.; Agudov, N.V.; Dubkov, A.A.

    2004-01-01

    The noise can stabilize a fluctuating or a periodically driven metastable state in such a way that the system remains in this state for a longer time than in the absence of white noise. This is the noise enhanced stability phenomenon, observed experimentally and numerically in different physical systems. After shortly reviewing all the physical systems where the phenomenon was observed, the theoretical approaches used to explain the effect are presented. Specifically the conditions to observe the effect in systems: (a) with periodical driving force, and (b) with random dichotomous driving force, are discussed. In case (b) we review the analytical results concerning the mean first passage time and the nonlinear relaxation time as a function of the white noise intensity, the parameters of the potential barrier, and of the dichotomous noise. (author)

  7. Lignite Fuel Enhancement

    Energy Technology Data Exchange (ETDEWEB)

    Charles Bullinger; Nenad Sarunac

    2010-03-31

    Pulverized coal power plants which fire lignites and other low-rank high-moisture coals generally operate with reduced efficiencies and increased stack emissions due to the impacts of high fuel moisture on stack heat loss and pulverizer and fan power. A process that uses plant waste heat sources to evaporate a portion of the fuel moisture from the lignite feedstock in a moving bed fluidized bed dryer (FBD) was developed in the U.S. by a team led by Great River Energy (GRE). The demonstration was conducted with Department of Energy (DOE) funding under DOE Award Number DE-FC26-04NT41763. The objectives of GRE's Lignite Fuel Enhancement project were to demonstrate reduction in lignite moisture content by using heat rejected from the power plant, apply technology at full scale at Coal Creek Station (CCS), and commercialize it. The Coal Creek Project has involved several stages, beginning with lignite drying tests in a laboratory-scale FBD at the Energy Research Center (ERC) and development of theoretical models for predicting dryer performance. Using results from these early stage research efforts, GRE built a 2 ton/hour pilot-scale dryer, and a 75 ton/hour prototype drying system at Coal Creek Station. Operated over a range of drying conditions, the results from the pilot-scale and prototype-scale dryers confirmed the performance of the basic dryer design concept and provided the knowledge base needed to scale the process up to commercial size. Phase 2 of the GRE's Lignite Fuel Enhancement project included design, construction and integration of a full-scale commercial coal drying system (four FBDs per unit) with Coal Creek Units 1 and 2 heat sources and coal handling system. Two series of controlled tests were conducted at Coal Creek Unit 1 with wet and dried lignite to determine effect of dried lignite on unit performance and emissions. Wet lignite was fired during the first, wet baseline, test series conducted in September 2009. The second test series was

  8. Enhanced Input in LCTL Pedagogy

    Directory of Open Access Journals (Sweden)

    Marilyn S. Manley

    2009-08-01

    Full Text Available Language materials for the more-commonly-taught languages (MCTLs often include visual input enhancement (Sharwood Smith 1991, 1993 which makes use of typographical cues like bolding and underlining to enhance the saliency of targeted forms. For a variety of reasons, this paper argues that the use of enhanced input, both visual and oral, is especially important as a tool for the lesscommonly-taught languages (LCTLs. As there continues to be a scarcity of teaching resources for the LCTLs, individual teachers must take it upon themselves to incorporate enhanced input into their own self-made materials. Specific examples of how to incorporate both visual and oral enhanced input into language teaching are drawn from the author’s own experiences teaching Cuzco Quechua. Additionally, survey results are presented from the author’s Fall 2010 semester Cuzco Quechua language students, supporting the use of both visual and oral enhanced input.

  9. Enhanced Input in LCTL Pedagogy

    Directory of Open Access Journals (Sweden)

    Marilyn S. Manley

    2010-08-01

    Full Text Available Language materials for the more-commonly-taught languages (MCTLs often include visual input enhancement (Sharwood Smith 1991, 1993 which makes use of typographical cues like bolding and underlining to enhance the saliency of targeted forms. For a variety of reasons, this paper argues that the use of enhanced input, both visual and oral, is especially important as a tool for the lesscommonly-taught languages (LCTLs. As there continues to be a scarcity of teaching resources for the LCTLs, individual teachers must take it upon themselves to incorporate enhanced input into their own self-made materials. Specific examples of how to incorporate both visual and oral enhanced input into language teaching are drawn from the author’s own experiences teaching Cuzco Quechua. Additionally, survey results are presented from the author’s Fall 2010 semester Cuzco Quechua language students, supporting the use of both visual and oral enhanced input.

  10. Development of enhanced radioprotectors

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Kyu; Park, K B; Lee, Y I [and others

    1999-04-01

    Biological model systems such as TSH mutations, animals and their reproductive organs, and cultured cell lines has been set up for screening radioprotective or radiosensitizing activities of natural products. About 100 natural plants were in vivo and in vitro tested. Among them, Salvia miltiorrhiza, Areca catechu, Cornus officinalis, and Portulaca oleracea showed 20% of radioprotective activities. On the other hand, Acanthopanax sessiliflous, Melia japonica, and Agastache rugosa revealed radiosensitizing activities. Experimental studies on the farnesyltransferase inhibitors showed the results that some of the inhibits lead to higher levels of cell death after {gamma} -irradiation and increased radiosensitivity in H-ras-transformed NIH3T3 cells and MCF-10A human tumor cells. Molecular biochemical studies on the mechanism of radioprotection was carried out using cultured cells. The treatment of DTT increased cell survival after gamma-irradiation, decreased in the frequencies of micronucleus, and reduction in DNA fragmentation and apoptotic cells. Induction of apoptosis after irradiation was revealed by the changes in the relative cell death, increase in the relative amount of apoptotic cells, and the induction of DNA fragmentation. Samples shown excellent radioprotective or radiosensitizing activities will be subjected to purification to develop radioprotectants and radiosensitizers applicable to human beings. The result of mechanism studies will be applied to elucidate the radioprotection mechanism and the develop enhanced radioprotectors. (author). 145 refs., 21 tabs., 29 figs.

  11. Enhanced Micellar Catalysis LDRD.

    Energy Technology Data Exchange (ETDEWEB)

    Betty, Rita G.; Tucker, Mark D; Taggart, Gretchen; Kinnan, Mark K.; Glen, Crystal Chanea; Rivera, Danielle; Sanchez, Andres; Alam, Todd Michael

    2012-12-01

    The primary goals of the Enhanced Micellar Catalysis project were to gain an understanding of the micellar environment of DF-200, or similar liquid CBW surfactant-based decontaminants, as well as characterize the aerosolized DF-200 droplet distribution and droplet chemistry under baseline ITW rotary atomization conditions. Micellar characterization of limited surfactant solutions was performed externally through the collection and measurement of Small Angle X-Ray Scattering (SAXS) images and Cryo-Transmission Electron Microscopy (cryo-TEM) images. Micellar characterization was performed externally at the University of Minnesotas Characterization Facility Center, and at the Argonne National Laboratory Advanced Photon Source facility. A micellar diffusion study was conducted internally at Sandia to measure diffusion constants of surfactants over a concentration range, to estimate the effective micelle diameter, to determine the impact of individual components to the micellar environment in solution, and the impact of combined components to surfactant phase behavior. Aerosolized DF-200 sprays were characterized for particle size and distribution and limited chemical composition. Evaporation rates of aerosolized DF-200 sprays were estimated under a set of baseline ITW nozzle test system parameters.

  12. Development of enhanced radioprotectors

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Kyu; Chun, K. J.; Lee, Y. K.; Kim, Y. K.; Lee, B. H.; Song, H. S.; Lee, C. J.; Chung, K. M.; Shin, H. S.; Park, T. W

    2000-04-01

    Biological model systems such as TSH mutations, animals and their reproductive organs, and cultured cell lines and human peripheral lymphocytes have been set up for screening radioprotective or radiosensitizing activities of natural products. About 100 natural plants were in vivo and in vitro tested. Among them, Salvia miltiorrhiza, Areca catechu, Cornus officinalis, and portulaca oleracea showed 20 percent of radioprotective activities. On the other hand, Acanthopanax sessiliflous, Melia japonica, and Agastache rugosa revealed radiosensitizing activities. Experimental studies on the farnesyl transferase inhibitors showed the results that some of the inhibitors lead to higher levels of cell death after {gamma}-irradiation and increased radiosensitivity in H-ras-transformed NIH3T3 cells and MCF-10A human tumor cells. Molecular biochemical studies on the mechanism of radioprotection was carried out using cultured cells. The treatment of DTT increased cell survival after gamma-irradiation,decreased in the frequencies of micronucleus, and reduction in DNA fragmentation and apoptotic cells. Induction of apoptosis after irradiation was revealed by the changes in the relative cell death, increase in the relative amount of apoptotic cells, and the induction of DNA fragmentation. The result of mechanism studies will be applied to elucidate the radioprotection mechanism and to develop enhanced radioprotectors. Furthermore, our results indicate that use of antioxidants in combination can efficiently modulate the radiation-induced cell damage like apoptosis and can be applied to alleviate the cellular damage in tumor patients during radiotherapy. (author)

  13. Enhanced sampling algorithms.

    Science.gov (United States)

    Mitsutake, Ayori; Mori, Yoshiharu; Okamoto, Yuko

    2013-01-01

    In biomolecular systems (especially all-atom models) with many degrees of freedom such as proteins and nucleic acids, there exist an astronomically large number of local-minimum-energy states. Conventional simulations in the canonical ensemble are of little use, because they tend to get trapped in states of these energy local minima. Enhanced conformational sampling techniques are thus in great demand. A simulation in generalized ensemble performs a random walk in potential energy space and can overcome this difficulty. From only one simulation run, one can obtain canonical-ensemble averages of physical quantities as functions of temperature by the single-histogram and/or multiple-histogram reweighting techniques. In this article we review uses of the generalized-ensemble algorithms in biomolecular systems. Three well-known methods, namely, multicanonical algorithm, simulated tempering, and replica-exchange method, are described first. Both Monte Carlo and molecular dynamics versions of the algorithms are given. We then present various extensions of these three generalized-ensemble algorithms. The effectiveness of the methods is tested with short peptide and protein systems.

  14. Enhancing chemical reactions

    Science.gov (United States)

    Morrey, John R.

    1978-01-01

    Methods of enhancing selected chemical reactions. The population of a selected high vibrational energy state of a reactant molecule is increased substantially above its population at thermal equilibrium by directing onto the molecule a beam of radiant energy from a laser having a combination of frequency and intensity selected to pump the selected energy state, and the reaction is carried out with the temperature, pressure, and concentrations of reactants maintained at a combination of values selected to optimize the reaction in preference to thermal degradation by transforming the absorbed energy into translational motion. The reaction temperature is selected to optimize the reaction. Typically a laser and a frequency doubler emit radiant energy at frequencies of .nu. and 2.nu. into an optical dye within an optical cavity capable of being tuned to a wanted frequency .delta. or a parametric oscillator comprising a non-centrosymmetric crystal having two indices of refraction, to emit radiant energy at the frequencies of .nu., 2.nu., and .delta. (and, with a parametric oscillator, also at 2.nu.-.delta.). Each unwanted frequency is filtered out, and each desired frequency is focused to the desired radiation flux within a reaction chamber and is reflected repeatedly through the chamber while reactants are fed into the chamber and reaction products are removed therefrom.

  15. Development of enhanced radioprotectors

    International Nuclear Information System (INIS)

    Kim, Jin Kyu; Chun, K. J.; Lee, Y. K.; Kim, Y. K.; Lee, B. H.; Song, H. S.; Lee, C. J.; Chung, K. M.; Shin, H. S.; Park, T. W.

    2000-04-01

    Biological model systems such as TSH mutations, animals and their reproductive organs, and cultured cell lines and human peripheral lymphocytes have been set up for screening radioprotective or radiosensitizing activities of natural products. About 100 natural plants were in vivo and in vitro tested. Among them, Salvia miltiorrhiza, Areca catechu, Cornus officinalis, and portulaca oleracea showed 20 percent of radioprotective activities. On the other hand, Acanthopanax sessiliflous, Melia japonica, and Agastache rugosa revealed radiosensitizing activities. Experimental studies on the farnesyl transferase inhibitors showed the results that some of the inhibitors lead to higher levels of cell death after γ-irradiation and increased radiosensitivity in H-ras-transformed NIH3T3 cells and MCF-10A human tumor cells. Molecular biochemical studies on the mechanism of radioprotection was carried out using cultured cells. The treatment of DTT increased cell survival after gamma-irradiation,decreased in the frequencies of micronucleus, and reduction in DNA fragmentation and apoptotic cells. Induction of apoptosis after irradiation was revealed by the changes in the relative cell death, increase in the relative amount of apoptotic cells, and the induction of DNA fragmentation. The result of mechanism studies will be applied to elucidate the radioprotection mechanism and to develop enhanced radioprotectors. Furthermore, our results indicate that use of antioxidants in combination can efficiently modulate the radiation-induced cell damage like apoptosis and can be applied to alleviate the cellular damage in tumor patients during radiotherapy. (author)

  16. Enhancing a Universe Below

    Energy Technology Data Exchange (ETDEWEB)

    Berge, Gunnar

    1998-12-31

    By understanding the past and by means of modern technology the petroleum resources can be exploited in an environmentally friendly and cost-effective way. Since the future of the oil and gas industry depends on the size and availability of the remaining resources and on the demand for the products, this presentation aims to overview these resources, globally and on the Norwegian Shelf. It also considers the uncertainty in the future demand for oil and gas. A key challenge for the industry is to enhance the value of these resources without compromising environmental values. The industry will also have to face issues such as deregulation of the energy markets, hydrocarbon taxation, etc. These challenges also provide possibilities for a proactive industry; how can we make the industry more competitive? New oil and gas fields are now being developed in deeper water, in harsh climate conditions and in vulnerable environments. These challenges call for technological development and strong focus on safety and environmental issues. Long-term commercial commitment and cooperation of the industry is essential for new technologies and for training. 2 figs.

  17. Development of enhanced radioprotectors

    International Nuclear Information System (INIS)

    Kim, Jin Kyu; Park, K.B.; Lee, Y.I.

    1999-04-01

    Biological model systems such as TSH mutations, animals and their reproductive organs, and cultured cell lines has been set up for screening radioprotective or radiosensitizing activities of natural products. About 100 natural plants were in vivo and in vitro tested. Among them, Salvia miltiorrhiza, Areca catechu, Cornus officinalis, and Portulaca oleracea showed 20% of radioprotective activities. On the other hand, Acanthopanax sessiliflous, Melia japonica, and Agastache rugosa revealed radiosensitizing activities. Experimental studies on the farnesyltransferase inhibitors showed the results that some of the inhibits lead to higher levels of cell death after γ -irradiation and increased radiosensitivity in H-ras-transformed NIH3T3 cells and MCF-10A human tumor cells. Molecular biochemical studies on the mechanism of radioprotection was carried out using cultured cells. The treatment of DTT increased cell survival after gamma-irradiation, decreased in the frequencies of micronucleus, and reduction in DNA fragmentation and apoptotic cells. Induction of apoptosis after irradiation was revealed by the changes in the relative cell death, increase in the relative amount of apoptotic cells, and the induction of DNA fragmentation. Samples shown excellent radioprotective or radiosensitizing activities will be subjected to purification to develop radioprotectants and radiosensitizers applicable to human beings. The result of mechanism studies will be applied to elucidate the radioprotection mechanism and the develop enhanced radioprotectors. (author). 145 refs., 21 tabs., 29 figs

  18. The Demand for Enhanced Annuities

    OpenAIRE

    Schuhmacher, Petra

    2008-01-01

    In enhanced annuities, the annuity payment depends on one's state of health at some contracted date while in "standard annuities", it does not. The focus of this paper is on an annuity market where "standard" and enhanced annuities areoffered simultaneously. When all insured know equally well on their future health status either enhanced annuities drive standard annuities out of the market or vice versa. Both annuity types can exist simultaneously when the insured know varying exactly on thei...

  19. Multispectral histogram normalization contrast enhancement

    Science.gov (United States)

    Soha, J. M.; Schwartz, A. A.

    1979-01-01

    A multispectral histogram normalization or decorrelation enhancement which achieves effective color composites by removing interband correlation is described. The enhancement procedure employs either linear or nonlinear transformations to equalize principal component variances. An additional rotation to any set of orthogonal coordinates is thus possible, while full histogram utilization is maintained by avoiding the reintroduction of correlation. For the three-dimensional case, the enhancement procedure may be implemented with a lookup table. An application of the enhancement to Landsat multispectral scanning imagery is presented.

  20. Enhancing operational nuclear safety

    International Nuclear Information System (INIS)

    Sengoku, Katsuhisa

    2008-01-01

    's safety standards and program which provides the safety objective following the 10 fundamental safety principles. The safety requirements defines the functional conditions required for safety and the safety guides provides user-friendly and up-to-date practical guidance representing good/best practices to fulfill the requirements. The IAEA provides safety review services and fields safety review teams upon request of member states for the regulatory, the International Regulatory Review Team (IRRT) and Operational Safety Review Team (OSART) and Peer Review of the Operational and Safety Performance Experience Review (PROSPER). The OSART programme's purpose is to assist member states in enhancing the operational safety of individual nuclear power plants and to promote the continuous development of operational safety within all member states by the dissemination of information on good practice. The OSART Mission Results (OSMIR) database contains the results from 73 OSART missions and 54 follow up visits from 1991 and its continually updated. The Asian Nuclear Safety Network (ANSN) was established to pool and share existing and new technical knowledge and practical experience to further improve the safety of nuclear installation in Asia. In summary, the enhancement of the GNSR is anchored in the recognition that all the states are in the same boat and the increasing importance of sharing and mutual learning, sharing knowledge and experience through regional and global networking. It requires joint and coordinated strategy by all states. The IAEA is willing and ready to support the GNSR through the establishment and application of safety standards, and safety review and advisory services and international instruments. (Author)

  1. Plasmon Enhanced Photoemission

    Energy Technology Data Exchange (ETDEWEB)

    Polyakov, Aleksandr [Univ. of California, Berkeley, CA (United States)

    2012-05-08

    this work, the structure consisted of rectangular nano-grooves (NGs) arranged in a subwavelength grating on a metal surface is presented that provides a dramatic increase in the metal’s absorption, field localization, and field enhancement. When light is polarized perpendicular to the orientation of the grooves a standing SPP wave is excited along the vertical walls in the NGs, that act as Fabry-Perot resonators. By adjusting the geometry of the NGs and the period of the subwavelength grating the resonance can be fine tuned to a desired position, for example, the laser fundamental wavelength, anywhere from the UV to the near infrared (NIR). Two types of gratings are presented: (a) a gold grating with period of 600 nm, and (b) an aluminum-gold grating with a period of 100 nm; both with resonance at 720 nm. In each case, strong on-resonance absorption was observed, with over 98% for grating (b). Unlike the grating-coupled SPP waves, where the angle is well defined by the momentum matching condition, the resonant NGs allow coupling to the standing modes at a range of angles of incidence, referred to as the angular bandwidth. A new model for the on-resonance absorption based on the ensamble action of the NGs is presented that serves as the basis for a design of an NG grating with an ultrawide spectral as well as angular bandwidth. For sample (b), the angular bandwidth is 80 degrees, corresponding to an opening angle of 160 degrees. The photoemission enhancement for such a grating was measured to be seven orders of magnitude for a four-photon photoemission. This is an incredible result demonstrating the power of the plasmonic grating presented, which is an efficient light trapper and field enhancer for a non-linear processes. These results demonstrate that the metal photocathode prepared with a NG grating on the metal surface will provide sufficient pulse charge driven by a 1 μJ 15fs pulsed laser at 800 nm for the optimum FEL operation.

  2. Radiographic enhancement and analysis system

    International Nuclear Information System (INIS)

    Schlosser, M.S.

    1981-01-01

    Radiographic image enhancement and analysis techniques are discussed as they apply to nondestructive inspection. A system is described which has been developed to enhance and quantitatively evaluate radiographic images using digital computer techniques. Some examples of typical applications are also presented as an introduction to this new inspection technique. (author)

  3. Enhancement of blurred image portions

    NARCIS (Netherlands)

    2008-01-01

    This invention relates to a method for image enhancement, comprising a first step ( 41 ) of distinguishing blurred and non-blurred image portions of an input image, and a second step ( 42 ) of enhancing at least one of said blurred image portions of said input image to produce an output image. Said

  4. Motif signatures of transcribed enhancers

    KAUST Repository

    Kleftogiannis, Dimitrios

    2017-09-14

    In mammalian cells, transcribed enhancers (TrEn) play important roles in the initiation of gene expression and maintenance of gene expression levels in spatiotemporal manner. One of the most challenging questions in biology today is how the genomic characteristics of enhancers relate to enhancer activities. This is particularly critical, as several recent studies have linked enhancer sequence motifs to specific functional roles. To date, only a limited number of enhancer sequence characteristics have been investigated, leaving space for exploring the enhancers genomic code in a more systematic way. To address this problem, we developed a novel computational method, TELS, aimed at identifying predictive cell type/tissue specific motif signatures. We used TELS to compile a comprehensive catalog of motif signatures for all known TrEn identified by the FANTOM5 consortium across 112 human primary cells and tissues. Our results confirm that distinct cell type/tissue specific motif signatures characterize TrEn. These signatures allow discriminating successfully a) TrEn from random controls, proxy of non-enhancer activity, and b) cell type/tissue specific TrEn from enhancers expressed and transcribed in different cell types/tissues. TELS codes and datasets are publicly available at http://www.cbrc.kaust.edu.sa/TELS.

  5. Metaheuristic applications to speech enhancement

    CERN Document Server

    Kunche, Prajna

    2016-01-01

    This book serves as a basic reference for those interested in the application of metaheuristics to speech enhancement. The major goal of the book is to explain the basic concepts of optimization methods and their use in heuristic optimization in speech enhancement to scientists, practicing engineers, and academic researchers in speech processing. The authors discuss why it has been a challenging problem for researchers to develop new enhancement algorithms that aid in the quality and intelligibility of degraded speech. They present powerful optimization methods to speech enhancement that can help to solve the noise reduction problems. Readers will be able to understand the fundamentals of speech processing as well as the optimization techniques, how the speech enhancement algorithms are implemented by utilizing optimization methods, and will be given the tools to develop new algorithms. The authors also provide a comprehensive literature survey regarding the topic.

  6. Resolution Enhancement of Multilook Imagery

    Energy Technology Data Exchange (ETDEWEB)

    Galbraith, Amy E. [Univ. of Arizona, Tucson, AZ (United States)

    2004-07-01

    This dissertation studies the feasibility of enhancing the spatial resolution of multi-look remotely-sensed imagery using an iterative resolution enhancement algorithm known as Projection Onto Convex Sets (POCS). A multi-angle satellite image modeling tool is implemented, and simulated multi-look imagery is formed to test the resolution enhancement algorithm. Experiments are done to determine the optimal con guration and number of multi-angle low-resolution images needed for a quantitative improvement in the spatial resolution of the high-resolution estimate. The important topic of aliasing is examined in the context of the POCS resolution enhancement algorithm performance. In addition, the extension of the method to multispectral sensor images is discussed and an example is shown using multispectral confocal fluorescence imaging microscope data. Finally, the remote sensing issues of atmospheric path radiance and directional reflectance variations are explored to determine their effect on the resolution enhancement performance.

  7. COMPARISON OF IMAGE ENHANCEMENT METHODS FOR CHROMOSOME KARYOTYPE IMAGE ENHANCEMENT

    Directory of Open Access Journals (Sweden)

    Dewa Made Sri Arsa

    2017-02-01

    Full Text Available The chromosome is a set of DNA structure that carry information about our life. The information can be obtained through Karyotyping. The process requires a clear image so the chromosome can be evaluate well. Preprocessing have to be done on chromosome images that is image enhancement. The process starts with image background removing. The image will be cleaned background color. The next step is image enhancement. This paper compares several methods for image enhancement. We evaluate some method in image enhancement like Histogram Equalization (HE, Contrast-limiting Adaptive Histogram Equalization (CLAHE, Histogram Equalization with 3D Block Matching (HE+BM3D, and basic image enhancement, unsharp masking. We examine and discuss the best method for enhancing chromosome image. Therefore, to evaluate the methods, the original image was manipulated by the addition of some noise and blur. Peak Signal-to-noise Ratio (PSNR and Structural Similarity Index (SSIM are used to examine method performance. The output of enhancement method will be compared with result of Professional software for karyotyping analysis named Ikaros MetasystemT M . Based on experimental results, HE+BM3D method gets a stable result on both scenario noised and blur image.

  8. Environmental engineering education enhancement

    Science.gov (United States)

    Caporali, E.

    2012-04-01

    Since higher education plays a central role in the development of both human beings and modern societies, enhancing social, cultural and economic development, active citizenship, ethical values and expertises for a sustainable growth, environment respectful, the European Commission promotes a wide range of programmes. Among the EC programmes, the TEMPUS - Trans European Mobility Programme for University Studies, with the support of the DG EAC of the European Commission, has contributed to many aspects of general interest for higher education. Curricula harmonization, LifeLong Learning Programme development, ICT use, quality assessment, accreditation, innovation learning methods, growth of networks of institutions trusting each other, are the focused aspects. Such a solid cooperation framework is surely among the main outcomes of the TEMPUS Projects leaded by the University of Firenze UNIFI (Italy), DEREC - Development of Environment and Resources Engineering Curriculum (2005-2008), and its spin-off DEREL - Development of Environment and Resources Engineering Learning (2010-2013), and VICES - Videoconferencing Educational Services (2009-2012). DEREC and DEREL TEMPUS projects, through the co-operation of Universities in Italy, Austria, Germany, Greece, Macedonia, Albania and Serbia, are aimed at the development of first and second level curricula in "Environment and Resources Engineering" at the Ss. Cyril and Methodius University - UKIM Skopje (MK). In the DEREC Project the conditions for offering a joint degree title in the field of Environmental Engineering between UNIFI and UKIM Skopje were fulfilled and a shared educational programme leading to the mutual recognition of degree titles was defined. The DEREL project, as logical continuation of DEREC, is aimed to introduce a new, up-to-date, postgraduate second level curriculum in Environment and Resources Engineering at UKIM Skopje, University of Novi Sad (RS) and Polytechnic University of Tirana (AL). following

  9. Enhanced Design Alternative IV

    International Nuclear Information System (INIS)

    Kramer, N.E.

    1999-01-01

    This report evaluates Enhanced Design Alternative (EDA) IV as part of the second phase of the License Application Design Selection (LADS) effort. The EDA IV concept was compared to the VA reference design using criteria from the Design Input Request for LADS Phase II EDA Evaluations (CRWMS M and O 1999b) and (CRWMS M and O 1999f). Briefly, the EDA IV concept arranges the waste packages close together in an emplacement configuration known as line load. Continuous pre-closure ventilation keeps the waste packages from exceeding their 350 C cladding and 200 C (4.3.6) drift wall temperature limits. This EDA concept keeps relatively high, uniform emplacement drift temperatures (post-closure) to drive water away from the repository and thus dry out the pillars between emplacement drifts. The waste package is shielded to permit human access to emplacement drifts and includes an integral filler inside the package to reduce the amount of water that can contact the waste form. Closure of the repository is desired 50 years after first waste is emplaced. Both backfill and drip shields will be emplaced at closure to improve post-closure performance. The EDA IV concept includes more defense-in-depth layers than the VA reference design because of its backfill, drip shield, waste package shielding, and integral filler features. These features contribute to the low dose-rate to the public achieved during the first 10,000 years of repository life as shown in Figure 3. Investigation of the EDA IV concept has led to the following general conclusions: (1) The total life cycle cost for EDA IV is about $21.7 billion which equates to a $11.3 billion net present value (both figures rounded up). (2) The incidence of design basis events for EDA IV is similar to the VA reference design. (3) The emplacement of the waste packages in drifts will be similar to the VA reference design. However, heavier equipment may be required because the shielded waste package will be heavier. (4) The heavier

  10. Excitation enhancement and extraction enhancement with photonic crystals

    Science.gov (United States)

    Shapira, Ofer; Soljacic, Marin; Zhen, Bo; Chua, Song-Liang; Lee, Jeongwon; Joannopoulos, John

    2015-03-03

    Disclosed herein is a system for stimulating emission from at least one an emitter, such as a quantum dot or organic molecule, on the surface of a photonic crystal comprising a patterned dielectric substrate. Embodiments of this system include a laser or other source that illuminates the emitter and the photonic crystal, which is characterized by an energy band structure exhibiting a Fano resonance, from a first angle so as to stimulate the emission from the emitter at a second angle. The coupling between the photonic crystal and the emitter may result in spectral and angular enhancement of the emission through excitation and extraction enhancement. These enhancement mechanisms also reduce the emitter's lasing threshold. For instance, these enhancement mechanisms enable lasing of a 100 nm thick layer of diluted organic molecules solution with reduced threshold intensity. This reduction in lasing threshold enables more efficient organic light emitting devices and more sensitive molecular sensing.

  11. Resolution enhancement techniques in microscopy

    Science.gov (United States)

    Cremer, Christoph; Masters, Barry R.

    2013-05-01

    We survey the history of resolution enhancement techniques in microscopy and their impact on current research in biomedicine. Often these techniques are labeled superresolution, or enhanced resolution microscopy, or light-optical nanoscopy. First, we introduce the development of diffraction theory in its relation to enhanced resolution; then we explore the foundations of resolution as expounded by the astronomers and the physicists and describe the conditions for which they apply. Then we elucidate Ernst Abbe's theory of optical formation in the microscope, and its experimental verification and dissemination to the world wide microscope communities. Second, we describe and compare the early techniques that can enhance the resolution of the microscope. Third, we present the historical development of various techniques that substantially enhance the optical resolution of the light microscope. These enhanced resolution techniques in their modern form constitute an active area of research with seminal applications in biology and medicine. Our historical survey of the field of resolution enhancement uncovers many examples of reinvention, rediscovery, and independent invention and development of similar proposals, concepts, techniques, and instruments. Attribution of credit is therefore confounded by the fact that for understandable reasons authors stress the achievements from their own research groups and sometimes obfuscate their contributions and the prior art of others. In some cases, attribution of credit is also made more complex by the fact that long term developments are difficult to allocate to a specific individual because of the many mutual connections often existing between sometimes fiercely competing, sometimes strongly collaborating groups. Since applications in biology and medicine have been a major driving force in the development of resolution enhancing approaches, we focus on the contribution of enhanced resolution to these fields.

  12. Ballast Water Self Monitoring

    Science.gov (United States)

    2011-11-01

    Hydrogen peroxide  Menadione /Vitamin K The efficacy of these processes varies by water conditions such as pH, temperature and, most significantly...Hydrocyclone power consumption, voltage and current Hydrocyclone power consumption, voltage and current Menadione /Vitamin K Menadione Chemical analysis...and treatment monitoring - Menadione /Vitamin K concentration at injection - Menadione /Vitamin K dosage and usage - Menadione /Vitamin K

  13. The use of intermediate electron acceptors to enhance MTT bioreduction in a microculture tetrazolium assay for human growth hormone.

    Science.gov (United States)

    Goodwin, C J; Holt, S J; Downes, S; Marshall, N J

    1996-01-01

    We contrast the effects of three intermediate electron acceptors (IEAs) on the highly quantitative ESTA bioassay for human growth hormone. This is a microculture tetrazolium assay based upon the in vitro reduction of the tetrazolium salt MTT, by Nb2 cells which have been activated with hGH. Each of the IEAs influenced MTT-formazan production in a distinctive manner. The two quinonoids, namely menadione and co-enzyme Q0 markedly increased the MTT-formazan produced by hormone activated Nb2 cells and thereby amplified the response of our bioassay for human growth hormone (hGH). The exceptionally low bioassay baseline which is characteristic of the unstimulated Nb2 cells when only MTT is added was retained in the presence of CoQ0, but was greatly increased by menadione. Phenazine methosulphate, which is the most widely used redox intermediary in microculture tetrazolium assays, also increased the baseline, but had only a minimal additional effect on MTT reduction by activated Nb2 cells. We conclude that CoQ0 is the preferred IEA for this ESTA bioassay for hGH.

  14. Speech enhancement theory and practice

    CERN Document Server

    Loizou, Philipos C

    2013-01-01

    With the proliferation of mobile devices and hearing devices, including hearing aids and cochlear implants, there is a growing and pressing need to design algorithms that can improve speech intelligibility without sacrificing quality. Responding to this need, Speech Enhancement: Theory and Practice, Second Edition introduces readers to the basic problems of speech enhancement and the various algorithms proposed to solve these problems. Updated and expanded, this second edition of the bestselling textbook broadens its scope to include evaluation measures and enhancement algorithms aimed at impr

  15. Surface-Enhanced Raman Spectroscopy

    Indian Academy of Sciences (India)

    IAS Admin

    weak Raman signal, which facilitates identification in chemi- cal and biological systems. Recently, single-molecule Raman scattering has enhanced the detection sensitivity limit of ... was working on the molecular diffraction of light, which ulti-.

  16. Motif signatures of transcribed enhancers

    KAUST Repository

    Kleftogiannis, Dimitrios A.; Ashoor, Haitham; Zarokanellos, Nikolaos; Bajic, Vladimir B.

    2017-01-01

    In mammalian cells, transcribed enhancers (TrEn) play important roles in the initiation of gene expression and maintenance of gene expression levels in spatiotemporal manner. One of the most challenging questions in biology today is how the genomic

  17. Geothermal Permeability Enhancement - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Joe Beall; Mark Walters

    2009-06-30

    The overall objective is to apply known permeability enhancement techniques to reduce the number of wells needed and demonstrate the applicability of the techniques to other undeveloped or under-developed fields. The Enhanced Geothermal System (EGS) concept presented in this project enhances energy extraction from reduced permeability zones in the super-heated, vapor-dominated Aidlin Field of the The Geysers geothermal reservoir. Numerous geothermal reservoirs worldwide, over a wide temperature range, contain zones of low permeability which limit the development potential and the efficient recovery of heat from these reservoirs. Low permeability results from poorly connected fractures or the lack of fractures. The Enhanced Geothermal System concept presented here expands these technologies by applying and evaluating them in a systematic, integrated program.

  18. Surface-Enhanced Raman Spectroscopy

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 15; Issue 2. Surface-Enhanced Raman Spectroscopy - Recent Advancement of Raman Spectroscopy. Ujjal Kumar Sur. General Article Volume 15 Issue 2 February 2010 pp 154-164 ...

  19. Moderate eugenics and human enhancement.

    Science.gov (United States)

    Selgelid, Michael J

    2014-02-01

    Though the reputation of eugenics has been tarnished by history, eugenics per se is not necessarily a bad thing. Many advocate a liberal new eugenics--where individuals are free to choose whether or not to employ genetic technologies for reproductive purposes. Though genetic interventions aimed at the prevention of severe genetic disorders may be morally and socially acceptable, reproductive liberty in the context of enhancement may conflict with equality. Enhancement could also have adverse effects on utility. The enhancement debate requires a shift in focus. What the equality and/or utility costs of enhancement will be is an empirical question. Rather than philosophical speculation, more social science research is needed to address it. Philosophers, meanwhile, should address head-on the question of how to strike a balance between liberty, equality, and utility in cases of conflict (in the context of genetics).

  20. WEATHERABILITY OF ENHANCED DEGRADABLE PLASTICS

    Science.gov (United States)

    The main objective of this study was to assess the performance and the asociated variability of several selected enhanced degradable plastic materials under a variety of different exposure conditions. Other objectives were to identify the major products formed during degradation ...

  1. Enhanced Master Station History Report

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Enhanced Master Station History Report (EMSHR) is a compiled list of basic, historical information for every station in the station history database, beginning...

  2. Bose enhancement and the ridge

    Energy Technology Data Exchange (ETDEWEB)

    Altinoluk, Tolga [Departamento de Física de Partículas and IGFAE, Universidade de Santiago de Compostela, 15706 Santiago de Compostela, Galicia (Spain); Armesto, Néstor, E-mail: nestor.armesto@usc.es [Departamento de Física de Partículas and IGFAE, Universidade de Santiago de Compostela, 15706 Santiago de Compostela, Galicia (Spain); Beuf, Guillaume [Department of Physics, Ben-Gurion University of the Negev, Beer Sheva 84105 (Israel); Kovner, Alex [Physics Department, University of Connecticut, 2152 Hillside Road, Storrs, CT 06269-3046 (United States); Lublinsky, Michael [Department of Physics, Ben-Gurion University of the Negev, Beer Sheva 84105 (Israel)

    2015-12-17

    We point out that Bose enhancement in a hadronic wave function generically leads to correlations between produced particles. We show explicitly, by calculating the projectile density matrix in the Color Glass Condensate approach to high-energy hadronic collisions, that the Bose enhancement of gluons in the projectile leads to azimuthal collimation of long range rapidity correlations of the produced particles, the so-called ridge correlations.

  3. Field enhancement induced laser ablation

    DEFF Research Database (Denmark)

    Fiutowski, Jacek; Maibohm, Christian; Kjelstrup-Hansen, Jakob

    Sub-diffraction spatially resolved, quantitative mapping of strongly localized field intensity enhancement on gold nanostructures via laser ablation of polymer thin films is reported. Illumination using a femtosecond laser scanning microscope excites surface plasmons in the nanostructures....... The accompanying field enhancement substantially lowers the ablation threshold of the polymer film and thus creates local ablation spots and corresponding topographic modifications of the polymer film. Such modifications are quantified straightforwardly via scanning electron and atomic force microscopy. Thickness...

  4. Luminescence enhancement in irradiated polyethylene

    International Nuclear Information System (INIS)

    Charlesby, A.; Owen, G.P.

    1976-01-01

    Results are presented for the luminescence decay in polyethylene following irradiation at liquid nitrogen temperature and its enhancement on application of an electric field. It is found that both the luminescence enhancement and its subsequent decay may be described by a model involving electron tunnelling from a monoenergetic trap distribution to the parent positive ion. The possible nature of the trap is briefly discussed. (author)

  5. Bose enhancement and the ridge

    Directory of Open Access Journals (Sweden)

    Tolga Altinoluk

    2015-12-01

    Full Text Available We point out that Bose enhancement in a hadronic wave function generically leads to correlations between produced particles. We show explicitly, by calculating the projectile density matrix in the Color Glass Condensate approach to high-energy hadronic collisions, that the Bose enhancement of gluons in the projectile leads to azimuthal collimation of long range rapidity correlations of the produced particles, the so-called ridge correlations.

  6. Enhanced sludge washing evaluation plan

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, R.D.

    1994-09-01

    The Tank Waste Remediation System (TWRS) Program mission is to store, treat, and immobilize highly radioactive Hanford Site waste (current and future tank waste and the strontium/cesium capsules) in an environmentally sound, safe, and cost-effective manner. The scope of the TWRS Waste Pretreatment Program is to treat tank waste and separate that waste into HLW and LLW fractions and provide additional treatment as required to feed LLW and HLW immobilization facilities. Enhanced sludge washing was chosen as the baseline process for separating Hanford tank waste sludge. Section 1.0 briefly discusses the purpose of the evaluation plan and provides the background that led to the choice of enhanced sludge washing as the baseline process. Section 2.0 provides a brief summary of the evaluation plan details. Section 3.0 discusses, in some detail, the technical work planned to support the evaluation of enhanced sludge washing. Section 4.0 briefly discusses the potential important of policy issues to the evaluation. Section 5.0 discusses the methodology to be used in the evaluation process. Section 6.0 summarizes the milestones that have been defined to complete the enhanced sludge washing evaluation and provides a summary schedule to evaluate the performance of enhanced sludge washing. References are identified in Section 7.0, and additional schedule and milestone information is provided in the appendices.

  7. The Misfortunes of Moral Enhancement.

    Science.gov (United States)

    Azevedo, Marco Antonio

    2016-10-01

    In Unfit for the Future, Ingmar Persson and Julian Savulescu present a sophisticated argument in defense of the imperative of moral enhancement. They claim that without moral enhancement, the future of humanity is seriously compromised. The possibility of ultimate harm, caused by a dreadful terrorist attack or by a final unpreventable escalation of the present environmental crisis aggravated by the availability of cognitive enhancement, makes moral enhancement a top priority. It may be considered optimistic to think that our present moral capabilities can be successfully improved by means of moral education, moral persuasion, and fear of punishment. So, without moral enhancement, drastic restrictions on human freedom would become the only alternative to prevent those dramatic potential outcomes. In this article, I will try to show that we still have reason to be less pessimistic and that Persson & Savulescu's arguments are fortunately unconvincing. © The Author 2016. Published by Oxford University Press, on behalf of the Journal of Medicine and Philosophy Inc. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  8. Enhanced sludge washing evaluation plan

    International Nuclear Information System (INIS)

    Jensen, R.D.

    1994-09-01

    The Tank Waste Remediation System (TWRS) Program mission is to store, treat, and immobilize highly radioactive Hanford Site waste (current and future tank waste and the strontium/cesium capsules) in an environmentally sound, safe, and cost-effective manner. The scope of the TWRS Waste Pretreatment Program is to treat tank waste and separate that waste into HLW and LLW fractions and provide additional treatment as required to feed LLW and HLW immobilization facilities. Enhanced sludge washing was chosen as the baseline process for separating Hanford tank waste sludge. Section 1.0 briefly discusses the purpose of the evaluation plan and provides the background that led to the choice of enhanced sludge washing as the baseline process. Section 2.0 provides a brief summary of the evaluation plan details. Section 3.0 discusses, in some detail, the technical work planned to support the evaluation of enhanced sludge washing. Section 4.0 briefly discusses the potential important of policy issues to the evaluation. Section 5.0 discusses the methodology to be used in the evaluation process. Section 6.0 summarizes the milestones that have been defined to complete the enhanced sludge washing evaluation and provides a summary schedule to evaluate the performance of enhanced sludge washing. References are identified in Section 7.0, and additional schedule and milestone information is provided in the appendices

  9. Moral enhancement requires multiple virtues.

    Science.gov (United States)

    Hughes, James J

    2015-01-01

    Some of the debates around the concept of moral enhancement have focused on whether the improvement of a single trait, such as empathy or intelligence, would be a good in general, or in all circumstances. All virtue theories, however, both secular and religious, have articulated multiple virtues that temper and inform one another in the development of a mature moral character. The project of moral enhancement requires a reengagement with virtue ethics and contemporary moral psychology to develop an empirically grounded model of the virtues and a fuller model of character development. Each of these virtues may be manipulable with electronic, psychopharmaceutical, and genetic interventions. A set of interdependent virtues is proposed, along with some of the research pointing to ways such virtues could be enhanced.

  10. Retinex enhancement of infrared images.

    Science.gov (United States)

    Li, Ying; He, Renjie; Xu, Guizhi; Hou, Changzhi; Sun, Yunyan; Guo, Lei; Rao, Liyun; Yan, Weili

    2008-01-01

    With the ability of imaging the temperature distribution of body, infrared imaging is promising in diagnostication and prognostication of diseases. However the poor quality of the raw original infrared images prevented applications and one of the essential problems is the low contrast appearance of the imagined object. In this paper, the image enhancement technique based on the Retinex theory is studied, which is a process that automatically retrieve the visual realism to images. The algorithms, including Frackle-McCann algorithm, McCann99 algorithm, single-scale Retinex algorithm, multi-scale Retinex algorithm and multi-scale Retinex algorithm with color restoration, are experienced to the enhancement of infrared images. The entropy measurements along with the visual inspection were compared and results shown the algorithms based on Retinex theory have the ability in enhancing the infrared image. Out of the algorithms compared, MSRCR demonstrated the best performance.

  11. Safety enhancement in NPP Bohunice

    International Nuclear Information System (INIS)

    Lipar, M.; Mihalik, M.

    1997-01-01

    The upgrading and safety enhancement of both the Bohunice V-1 and V-2 reactors is described in detail. The total estimated cost of the gradual reconstruction of these two units during 1996 to 1999 is 180 mil. US dollars. For the 1995 to 1997 period, the actions common for both units include a quality assurance programme, a personnel training programme, installation of a multifunction simulator, implementation of symptom-oriented operation procedures, installation of diagnostic systems, of a site security system, and of a teledosimetric system. At present, the main maintenance tasks are: to carry out major repair of units, to remedy service interruptions, to enhance equipment service availability, to enhance the technical level of corrective actions at equipment. Investment into maintenance level upgrade has grown from 7.5 mil. Slovak crowns in 1994 to estimated 32 mil. in 2000. The partners of international cooperation are mentioned. (M.D.)

  12. Contrast enhancement CT by iopamidol

    International Nuclear Information System (INIS)

    Mori, Masaki; Makita, Nobue; Yanai, Kyoko

    1984-01-01

    In order to evaluate the contrast enhancement effect and safety of iopamidol (IOP) in CT examination, IOP was compared with angiographin (AG). In the liver and abdominal aorta, peak CT values were obtained earlier and were higher in the group with AG than in the group with IOP. However, CT values in the group with IOP decreased a little more slowly than those in the group with AG. There was no significant difference in the effect on contrast enhancement between the groups. Intravenous injection of IOP caused lower degree of burning sensation than that of AG, and some of the patients with IOP did not feel burning sensation at all. Changes in clinical laboratory values were slight before and after intravenous injection of IOP. These results suggest that IOP is satisfactory in terms of safety and effect on contrast enhancement in CT examination. (Namekawa, K.)

  13. Nanoparticles for cells proliferation enhancement

    International Nuclear Information System (INIS)

    Popa, V.; Braniste, F.; Tiginyanu, I.M.; Lisii, C.; Nacu, V.

    2013-01-01

    The potential of semiconductor nanoparticles as stimulator for avian mesenchyme stem cells proliferation enhancement is demonstrated. The effect is related to nanoparticles polarization due to external ultrasound field resulting in local electrical stimulation. Our preliminary results demonstrates that the number of cells have been increased by 23 % ±2%) in cell cultures under the action of external ultrasound stimulation. Morphological analysis and viability shows no differences between the control group and the group studied. These results suggest the possibility for tissue regeneration enhancement by remote stimulation of implanted semiconductor nanoparticles. (authors)

  14. Bibliometric-enhanced information retrieval

    NARCIS (Netherlands)

    Mayr, Philipp; Scharnhorst, Andrea; Larsen, Birger; Schaer, Philipp; Mutschke, Peter

    2014-01-01

    Bibliometric techniques are not yet widely used to enhance retrieval processes in digital libraries, although they offer value-added effects for users. In this workshop we will explore how statistical modelling of scholarship, such as Bradfordizing or network analysis of coauthorship network, can

  15. Innovative Solution to Video Enhancement

    Science.gov (United States)

    2001-01-01

    Through a licensing agreement, Intergraph Government Solutions adapted a technology originally developed at NASA's Marshall Space Flight Center for enhanced video imaging by developing its Video Analyst(TM) System. Marshall's scientists developed the Video Image Stabilization and Registration (VISAR) technology to help FBI agents analyze video footage of the deadly 1996 Olympic Summer Games bombing in Atlanta, Georgia. VISAR technology enhanced nighttime videotapes made with hand-held camcorders, revealing important details about the explosion. Intergraph's Video Analyst System is a simple, effective, and affordable tool for video enhancement and analysis. The benefits associated with the Video Analyst System include support of full-resolution digital video, frame-by-frame analysis, and the ability to store analog video in digital format. Up to 12 hours of digital video can be stored and maintained for reliable footage analysis. The system also includes state-of-the-art features such as stabilization, image enhancement, and convolution to help improve the visibility of subjects in the video without altering underlying footage. Adaptable to many uses, Intergraph#s Video Analyst System meets the stringent demands of the law enforcement industry in the areas of surveillance, crime scene footage, sting operations, and dash-mounted video cameras.

  16. Motivation Enhancement Through Work Redesign.

    Science.gov (United States)

    Oldham, Greg R., Kulik, Carol T.

    1983-01-01

    The possibility of redesigning the work experiences of faculty members in an effort to enhance their motivation, productivity, and personal and work satisfactions is examined. One approach to work redesign, job characteristics theory, is described. Several strategies are discussed. (Author/MLW)

  17. Enhancing hydrogen spillover and storage

    Science.gov (United States)

    Yang, Ralph T [Ann Arbor, MI; Li, Yingwel [Ann Arbor, MI; Lachawiec, Jr., Anthony J.

    2011-05-31

    Methods for enhancing hydrogen spillover and storage are disclosed. One embodiment of the method includes doping a hydrogen receptor with metal particles, and exposing the hydrogen receptor to ultrasonification as doping occurs. Another embodiment of the method includes doping a hydrogen receptor with metal particles, and exposing the doped hydrogen receptor to a plasma treatment.

  18. Does Caffeine Enhance Athletic Performance?

    Directory of Open Access Journals (Sweden)

    Marcou Juliana

    2016-04-01

    Conclusion: Caffeine consumption may enhance athletic endurance, based on strong evidence, but further research needs to be conducted. High caffeine doses than the optimal, 3-6 mg/kg, before exercise does not confer any additional improvement in athletic performance. Additional, higher caffeine doses may cause side effects in athletes.

  19. Enhanced reality live role playing

    OpenAIRE

    Söderberg, Jonas; Waern, Annika; Åkesson, Karl-Petter; Björk, Staffan; Falk, Jennica

    2004-01-01

    Live role-playing is a form of improvisational theatre played for the experience of the performers and without an audience. These games form a challenging application domain for ubiquitous technology. We discuss the design options for enhanced reality live role-playing and the role of technology in live role-playing games.

  20. Key Issue: Enhancing Teacher Leadership

    Science.gov (United States)

    National Comprehensive Center for Teacher Quality, 2007

    2007-01-01

    "Teachers are leaders when they function in professional communities to affect student learning; contribute to school improvement; inspire excellence in practice; and empower stakeholders to participate in educational improvement" (Childs-Bowen, Moller, & Scrivner, 2000, p. 28). Enhancing teacher leadership can help schools and districts reach the…

  1. Who Benefits from Pension Enhancements?

    Science.gov (United States)

    Koedel, Cory; Ni, Shawn; Podgursky, Michael

    2014-01-01

    During the late 1990s public pension funds across the United States accrued large actuarial surpluses. The seemingly flush conditions of the pension funds led legislators in most states to substantially improve retirement benefits for public workers, including teachers. In this study we examine the benefit enhancements to the teacher pension…

  2. Enhanced care for depression : Review

    NARCIS (Netherlands)

    Beekman, A.J.; van der Feltz-Cornelis, C.M.; van Marwijk, H.W.J.

    2013-01-01

    Purpose of review: The purpose of this study is to review recent evidence of the effects of enhanced depression care, focusing (1) on symptomatic, functional and economic outcomes and (2) across different countries, (3) ethnic groups and (4) settings. Recent findings: Collaborative care is currently

  3. SUPRA - Enhanced upset recovery simulation

    NARCIS (Netherlands)

    Groen, E.; Ledegang, W.; Field, J.; Smaili, H.; Roza, M.; Fucke, L.; Nooij, S.; Goman, M.; Mayrhofer, M.; Zaichik, L.E.; Grigoryev, M.; Biryukov, V.

    2012-01-01

    The SUPRA research project - Simulation of Upset Recovery in Aviation - has been funded by the European Union 7th Framework Program to enhance the flight simulation envelope for upset recovery simulation. Within the project an extended aerodynamic model, capturing the key aerodynamics during and

  4. Engage, Enhance, and Extend Learning!

    Science.gov (United States)

    Keren-Kolb, Liz

    2013-01-01

    Educators often say that technology is more than a gimmick or add-on, and that it should engage, enhance, or extend learning in ways that traditional tools do not. Yet they seldom stop to define these terms, and they can be confusing, especially for teachers and preservice teachers. Recently, while collaborating on an English language arts and…

  5. Biosurfactant and enhanced oil recovery

    Science.gov (United States)

    McInerney, Michael J.; Jenneman, Gary E.; Knapp, Roy M.; Menzie, Donald E.

    1985-06-11

    A pure culture of Bacillus licheniformis strain JF-2 (ATCC No. 39307) and a process for using said culture and the surfactant lichenysin produced thereby for the enhancement of oil recovery from subterranean formations. Lichenysin is an effective surfactant over a wide range of temperatures, pH's, salt and calcium concentrations.

  6. Advances in heat transfer enhancement

    CERN Document Server

    Saha, Sujoy Kumar; Sundén, Bengt; Wu, Zan

    2016-01-01

    This Brief addresses the phenomena of heat transfer enhancement. A companion edition in the SpringerBrief Subseries on Thermal Engineering and Applied Science to three other monographs including “Critical Heat Flux in Flow Boiling in Microchannels,” this volume is idea for professionals, researchers, and graduate students concerned with electronic cooling.

  7. Enhancing Literacy Skills through Technology.

    Science.gov (United States)

    Sistek-Chandler, Cynthia

    2003-01-01

    Discusses how to use technology to enhance literacy skills. Highlights include defining literacy, including information literacy; research to support reading and writing instruction; literacy software; thinking skills; organizational strategies for writing and reading; how technology can individualize literacy instruction; and a new genre of…

  8. Ring enhancement in recurrent gliomas

    International Nuclear Information System (INIS)

    Ogashiwa, Motohide; Takeuchi, Kazuo; Akai, Keiichiro

    1981-01-01

    The clinical courses,CT scans, and postmortem reports for 6 glioma patients treated by surgery, radiation, and chemotherapy were reviewed. They underwent reoperation and/or retreatment with radiation or chemotherapy for recurrent tumors. CT scans taken at the time of recurrence or about one month prior to death showed ring enhancement of varied size and form after intensive treatment. The cases were examined histologically in correlation with the CT features and divided into two groups based on the pathological findings in the centers surrounded by areas of ring enhancement. The 1st group demonstrated a large necrotic area in the center, and the 2nd group, a cystic tumor. Tumor cells were found to have spread throughout the high-density areas around the necrotic area or cyst. However, gross differentiation between tumor and necrosis was difficult. In addition to an increase in cellularity, all cases demonstrated vascular proliferation, and dilatation of vessels in the sulci or sulci adjacent to gyri invaded by the tumor. The contrast enhancement corresponded well with the vascular proliferation in these areas. It is concluded that vascular proliferation or dilatation of vessels in and around the tumor is an important factor in demonstrating high-density areas in ring enhancement, while a cyst or necrosis in the tumor center is revealed as a low-density area in the CT scan of recurrent gliomas. (author)

  9. Ring enhancement in recurrent gliomas

    Energy Technology Data Exchange (ETDEWEB)

    Ogashiwa, M; Takeuchi, K; Akai, K [Kyorin Univ., Mitaka, Tokyo (Japan). School of Medicine

    1981-08-01

    The clinical courses,CT scans, and postmortem reports for 6 glioma patients treated by surgery, radiation, and chemotherapy were reviewed. They underwent reoperation and/or retreatment with radiation or chemotherapy for recurrent tumors. CT scans taken at the time of recurrence or about one month prior to death showed ring enhancement of varied size and form after intensive treatment. The cases were examined histologically in correlation with the CT features and divided into two groups based on the pathological findings in the centers surrounded by areas of ring enhancement. The 1st group demonstrated a large necrotic area in the center, and the 2nd group, a cystic tumor. Tumor cells were found to have spread throughout the high-density areas around the necrotic area or cyst. However, gross differentiation between tumor and necrosis was difficult. In addition to an increase in cellularity, all cases demonstrated vascular proliferation, and dilatation of vessels in the sulci or sulci adjacent to gyri invaded by the tumor. The contrast enhancement corresponded well with the vascular proliferation in these areas. It is concluded that vascular proliferation or dilatation of vessels in and around the tumor is an important factor in demonstrating high-density areas in ring enhancement, while a cyst or necrosis in the tumor center is revealed as a low-density area in the CT scan of recurrent gliomas.

  10. Bubble chamber: colour enhanced tracks

    CERN Multimedia

    1998-01-01

    This artistically-enhanced image of real particle tracks was produced in the Big European Bubble Chamber (BEBC). Liquid hydrogen is used to create bubbles along the paths of the particles as a piston expands the medium. A magnetic field is produced in the detector causing the particles to travel in spirals, allowing charge and momentum to be measured.

  11. Subendometrial enhancement and peritumoral enhancement for assessing endometrial cancer on dynamic contrast enhanced MR imaging

    International Nuclear Information System (INIS)

    Fujii, Shinya; Kido, Aki; Baba, Tsukasa; Fujimoto, Koji; Daido, Sayaka; Matsumura, Noriomi; Konishi, Ikuo; Togashi, Kaori

    2015-01-01

    Highlights: •We have assessed the peritumoral enhancement (PTE), which mimics SEE on DCE. •We evaluated the diagnostic accuracy of SEE for the myometrial invasion and the frequency of PTE. •We assessed the relationship between these enhancements and important pathologic factors. •PTE Type 1 is the main factor causing the overestimation of myometrial invasion using SEE on DCE. •PTE Type 2 correlates the myometrial invasion and may play an important role in the diagnosis of LVSI. -- Abstract: Objectives: To evaluate the diagnostic accuracy of subendometrial enhancement (SEE) in assessing the myometrial invasion in endometrial cancer, the frequency and clinical significance of peritumoral enhancement (PTE) on dynamic contrast enhanced (DCE) imaging. Materials and methods: MR images of 147 patients with endometrial cancer were retrospectively analyzed for intact SEE and PTEs: Type 1, a focal early enhancement peritumorally, and Type 2, an irregular thin-layered early intense enhancement peritumorally. Two radiologists independently assessed intact SEE and PTEs on DCE imaging and compared the lesions by the presence and depth of myometrial invasion, grade, lymphovascular space involvement (LVSI), and lymph node metastasis. The relationship between SEE, PTEs, and each factor was analyzed using univariate and multivariate analyses. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy were calculated for SEE. Results: The sensitivity, specificity, PPV, NPV and diagnostic accuracy for myometrial invasion based on SEE disruption on DCE were 96.6%, 32.1–46.4%, 85.8–88.5%, 69.2–76.5%, and 84.4–87.1%. According to multivariate analysis, SEE significantly predicted myometrial invasion (p < 0.0001). PTE Type 2 significantly predicted myometrial invasion presence (p < 0.05) and depth (p < 0.01). Conclusion: Diagnosis of myometrial invasion only by using SEE might be difficult on DCE-MRI due to the

  12. Subendometrial enhancement and peritumoral enhancement for assessing endometrial cancer on dynamic contrast enhanced MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, Shinya [Division of Radiology, Department of Pathophysiological and Therapeutic Science, Faculty of Medicine, Tottori University, Yonago (Japan); Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, Kyoto (Japan); Kido, Aki, E-mail: akikido@kuhp.kyoto-u.ac.jp [Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, Kyoto (Japan); Baba, Tsukasa [Departments of Gynecology and Obstetrics, Graduate School of Medicine, Kyoto University, Kyoto (Japan); Fujimoto, Koji; Daido, Sayaka [Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, Kyoto (Japan); Matsumura, Noriomi; Konishi, Ikuo [Departments of Gynecology and Obstetrics, Graduate School of Medicine, Kyoto University, Kyoto (Japan); Togashi, Kaori [Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, Kyoto (Japan)

    2015-04-15

    Highlights: •We have assessed the peritumoral enhancement (PTE), which mimics SEE on DCE. •We evaluated the diagnostic accuracy of SEE for the myometrial invasion and the frequency of PTE. •We assessed the relationship between these enhancements and important pathologic factors. •PTE Type 1 is the main factor causing the overestimation of myometrial invasion using SEE on DCE. •PTE Type 2 correlates the myometrial invasion and may play an important role in the diagnosis of LVSI. -- Abstract: Objectives: To evaluate the diagnostic accuracy of subendometrial enhancement (SEE) in assessing the myometrial invasion in endometrial cancer, the frequency and clinical significance of peritumoral enhancement (PTE) on dynamic contrast enhanced (DCE) imaging. Materials and methods: MR images of 147 patients with endometrial cancer were retrospectively analyzed for intact SEE and PTEs: Type 1, a focal early enhancement peritumorally, and Type 2, an irregular thin-layered early intense enhancement peritumorally. Two radiologists independently assessed intact SEE and PTEs on DCE imaging and compared the lesions by the presence and depth of myometrial invasion, grade, lymphovascular space involvement (LVSI), and lymph node metastasis. The relationship between SEE, PTEs, and each factor was analyzed using univariate and multivariate analyses. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy were calculated for SEE. Results: The sensitivity, specificity, PPV, NPV and diagnostic accuracy for myometrial invasion based on SEE disruption on DCE were 96.6%, 32.1–46.4%, 85.8–88.5%, 69.2–76.5%, and 84.4–87.1%. According to multivariate analysis, SEE significantly predicted myometrial invasion (p < 0.0001). PTE Type 2 significantly predicted myometrial invasion presence (p < 0.05) and depth (p < 0.01). Conclusion: Diagnosis of myometrial invasion only by using SEE might be difficult on DCE-MRI due to the

  13. Stimulation of ceramide formation and suicidal erythrocyte death by vitamin K(3) (menadione).

    Science.gov (United States)

    Qadri, Syed M; Eberhard, Matthias; Mahmud, Hasan; Föller, Michael; Lang, Florian

    2009-11-25

    Vitamin K(3) is an essential micronutrient required for the activation of coagulation factors and thus hemostasis. Administration of vitamin K(3) analogues may cause anemia, which at least in theory could be due to stimulation of suicidal erythrocyte death or eryptosis characterized by cell shrinkage and phospholipid scrambling of the erythrocyte cell membrane leading to exposure of phosphatidylserine at the erythrocyte surface. Eryptosis is triggered by an increase in the cytosolic Ca(2+) activity, by ceramide and by energy depletion (decrease of cytosolic ATP). The present experiments explored, whether vitamin K(3) may influence eryptosis. Hemolysis was estimated from the supernatant hemoglobin concentration, phosphatidylserine-exposing erythrocytes from annexin V-binding in fluorescence-activated cell sorter (FACS) analysis, erythrocyte volume from forward scatter in FACS analysis, ceramide formation from binding of fluorescent antibodies, and erythrocyte ATP content from a luciferin-luciferase assay. As a result, vitamin K(3) (> or =1microM) caused lysis of an only small fraction of erythrocytes, but significantly increased ceramide formation, significantly increased the percentage of annexin V-binding erythrocytes, significantly decreased forward scatter and, at higher concentrations, significantly decreased the cellular ATP content. In conclusion, vitamin K(3) stimulates suicidal erythrocyte death, an effect at least partially due to ceramide formation and ATP depletion.

  14. Contrast enhanced CT of spinal cord angioma

    International Nuclear Information System (INIS)

    Nakamura, Takahiko; Ebitani, Tsutomu; Honma, Takao; Sofue, Muroto; Nakamura, Shigeru

    1982-01-01

    Contrast enhanced CT on 6 patients with spinal cord angioma showed enhancement in 2 of them. The conditions to produce contrast enhancement were the window width of 100 - 200, and the window level of 0 - 50. In spinal cord angioma, contrast enhanced CT is presently only an adjunct to angiography and myelography. Nevertheless, contrast enhanced CT is useful in the screening test for spinal cord angioma, in the patients who are nonindicated to angiography, and in the postoperative follow-up. (Ueda, J.)

  15. Enhancement pattern of hilar cholangiocarcinoma: Contrast-enhanced ultrasound versus contrast-enhanced computed tomography

    International Nuclear Information System (INIS)

    Xu Huixiong; Chen Lida; Xie Xiaoyan; Xie Xiaohua; Xu Zuofeng; Liu Guangjian; Lin Manxia; Wang Zhu; Lu Mingde

    2010-01-01

    Objective: To compare the enhancement pattern of hilar cholangiocarcinoma on contrast-enhanced ultrasound (CEUS) with that on contrast-enhanced computed tomography (CECT). Methods: Thirty-two consecutive patients with pathologically proven hilar cholangiocarcinomas were evaluated by both low mechanical index CEUS and CECT. The enhancement feature of the tumor, portal vein infiltration, and lesion conspicuity on them was investigated. Results: In the arterial phase, the numbers of the lesions showing hyperenhancement, isoenhancement, and hypoenhancement, were 14 (43.8%), 14 (43.8%), and 4 (12.6%), on CEUS, and 12 (37.5%), 9 (28.1%), and 11 (34.4%), on CECT (P = 0.162). In portal phase, the numbers of the lesions showing hypoenhancement, isoenhancement, and hyperenhancement were 30 (93.8%), 1 (3.1%), and 1 (3.1%), on CEUS, and 23 (71.9%), 8 (25.0%), and 1 (3.1%), on CECT (P = 0.046). The detection rates for portal vein infiltration were 84.2% (16/19) for baseline ultrasound, 89.5% (17/19) for CEUS, and 78.9% (15/19) for CECT (all P > 0.05 between every two groups). CEUS significantly improved the lesion conspicuity in comparison with CECT. CEUS and CECT made correct diagnoses in 30 (93.8%) and 25 (78.1%) lesions prior to pathological examination (P = 0.125). Conclusion: The enhancement pattern of hilar cholangiocarcinoma on CEUS was similar with that on CECT in arterial phase, whereas in portal phase hilar cholangiocarcinoma shows hypoenhancement more likely on CEUS. CEUS and CECT lead to similar results in evaluating portal vein infiltration and diagnosis of this entity.

  16. Enhancement pattern of hilar cholangiocarcinoma: Contrast-enhanced ultrasound versus contrast-enhanced computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Xu Huixiong, E-mail: xuhuixiong@hotmail.co [Department of Medical Ultrasonics, The First Affiliated Hospital, Institute of Diagnostic and Interventional Ultrasound, Sun Yat-Sen University, 58 Zhongshan Road 2, Guangzhou 510080 (China); Chen Lida; Xie Xiaoyan; Xie Xiaohua; Xu Zuofeng; Liu Guangjian; Lin Manxia; Wang Zhu [Department of Medical Ultrasonics, The First Affiliated Hospital, Institute of Diagnostic and Interventional Ultrasound, Sun Yat-Sen University, 58 Zhongshan Road 2, Guangzhou 510080 (China); Lu Mingde, E-mail: lumd@21cn.co [Department of Hepatobiliary Surgery, First Affiliated Hospital, Sun Yat-Sen University, 58 Zhongshan Road 2, Guangzhou 510080 (China)

    2010-08-15

    Objective: To compare the enhancement pattern of hilar cholangiocarcinoma on contrast-enhanced ultrasound (CEUS) with that on contrast-enhanced computed tomography (CECT). Methods: Thirty-two consecutive patients with pathologically proven hilar cholangiocarcinomas were evaluated by both low mechanical index CEUS and CECT. The enhancement feature of the tumor, portal vein infiltration, and lesion conspicuity on them was investigated. Results: In the arterial phase, the numbers of the lesions showing hyperenhancement, isoenhancement, and hypoenhancement, were 14 (43.8%), 14 (43.8%), and 4 (12.6%), on CEUS, and 12 (37.5%), 9 (28.1%), and 11 (34.4%), on CECT (P = 0.162). In portal phase, the numbers of the lesions showing hypoenhancement, isoenhancement, and hyperenhancement were 30 (93.8%), 1 (3.1%), and 1 (3.1%), on CEUS, and 23 (71.9%), 8 (25.0%), and 1 (3.1%), on CECT (P = 0.046). The detection rates for portal vein infiltration were 84.2% (16/19) for baseline ultrasound, 89.5% (17/19) for CEUS, and 78.9% (15/19) for CECT (all P > 0.05 between every two groups). CEUS significantly improved the lesion conspicuity in comparison with CECT. CEUS and CECT made correct diagnoses in 30 (93.8%) and 25 (78.1%) lesions prior to pathological examination (P = 0.125). Conclusion: The enhancement pattern of hilar cholangiocarcinoma on CEUS was similar with that on CECT in arterial phase, whereas in portal phase hilar cholangiocarcinoma shows hypoenhancement more likely on CEUS. CEUS and CECT lead to similar results in evaluating portal vein infiltration and diagnosis of this entity.

  17. Enhancing undergraduate students’ communications skills

    DEFF Research Database (Denmark)

    Jørgensen, Merete; Witt, Klaus; Fridorff-Jens, Peter Kindt

    2014-01-01

    ,Monika Bullinger,Matthias Rose, Sylke Andreas.Enhancing medical students' communication skills: development and evaluation of an undergraduate training program.Published online 2012 March 24. doi: 10.1186/1472-6920-12-16 2.William T. Branch, Jr, MD; David Kern, MD; Paul Haidet, MD, MPH; Peter Weissmann, MD......19729 Abstract Title: Enhancing undergraduate students communications skills Abstract Authors: •Merete Jorgensen, Copenhagen University , Family Medicine , Copenhagen •Klaus Witt, Research Unit , Family Medicine , Copenhagen •Peter Kindt Fridorff-Jens, Copenhagen University , IT-unit , Copenhagen...... Abstract Presenter(s): •Merete Jorgensen, Copenhagen University , Family Medicine , Øster Farigmagsgade 5 , 1014 , K , Denmark , mejor@sund.ku.dk Abstract: Background Being teachers in Clinical Course of Family Medicine since 1995, we have developed two schemes for communication analysing purposes called...

  18. Biosurfactant-enhanced soil bioremediation

    Energy Technology Data Exchange (ETDEWEB)

    Kosaric, N.; Lu, G.; Velikonja, J. [Univ. of Western Ontario, London, Ontario (Canada)

    1995-12-01

    Bioremediation of soil contaminated with organic chemicals is a viable alternative method for clean-up and remedy of hazardous waste sites. The final objective in this approach is to convert the parent toxicant into a readily biodegradable product which is harmless to human health and/or the environment. Biodegradation of hydrocarbons in soil can also efficiently be enhanced by addition or in-situ production of biosufactants. It was generally observed that the degradation time was shortened and particularly the adaptation time for the microbes. More data from our laboratories showed that chlorinated aromatic compounds, such as 2,4-dichlorophenol, a herbicide Metolachlor, as well as naphthalene are degraded faster and more completely when selected biosurfactants are added to the soil. More recent data demonstrated an enhanced biodegradation of heavy hydrocarbons in petrochemical sludges, and in contaminated oil when biosurfactants were present or were added prior to the biodegradation process.

  19. Method for enhanced oil recovery

    Science.gov (United States)

    Comberiati, Joseph R.; Locke, Charles D.; Kamath, Krishna I.

    1980-01-01

    The present invention is directed to an improved method for enhanced recovery of oil from relatively "cold" reservoirs by carbon dioxide flooding. In oil reservoirs at a temperature less than the critical temperature of 87.7.degree. F. and at a pore pressure greater than the saturation pressure of carbon dioxide at the temperature of the reservoir, the carbon dioxide remains in the liquid state which does not satisfactorily mix with the oil. However, applicants have found that carbon dioxide can be vaporized in situ in the reservoir by selectively reducing the pore pressure in the reservoir to a value less than the particular saturated vapor pressure so as to greatly enhance the mixing of the carbon dioxide with the oil.

  20. Hereditary syndromes with enhanced radiosensitivity

    International Nuclear Information System (INIS)

    Lohmann, D.

    2000-01-01

    Sensitivity to ionizing radiation is modified by heritable genetic factors. This is exemplified by heritable disorders that are characterized by predisposition to the development of neoplasms. Cells derived from patients with ataxia telangiectasia, Nijmegen breakage syndrome and ataxia telangiektasia-like disorder show a markedly changed reaction to exposure to ionizing radiation. Correspondingly, at least in patients with ataxia telangiectasia, an enhanced radiosensitivity that is of clinical importance has been observed. In addition to these recessive disorders, some autosomal dominant cancer predisposition syndromes are associated with increased radiosensitivity. As cells from these patients still have a normal allele (that is dominant over the mutant allele), the cellular phenotype is most often normal. Specifically, there is no overtly altered reaction in response to ionizing radiation. Nevertheless, two dominant cancer predisposition syndromes, namely hereditary retinoblastoma and naevoid basal cell carcinoma syndrome, are associated with a enhanced radiosensitivity as indicated by increased development of tumors following radiation therapy. (orig.) [de

  1. Vasovist-enhanced MR angiography

    International Nuclear Information System (INIS)

    Goyen, M.; Shamsi, K.; Schoenberg, S.O.

    2006-01-01

    Vasovist (MS-325) is the first intravascular contrast agent approved for use with magnetic resonance angiography in the European Union. Vasovist reversibly binds to albumin, providing extended intravascular enhancement compared to existing extracellular magnetic resonance contrast agents. Prior to approval, Vasovist underwent extensive testing to evaluate the safety and efficacy of the drug; the clinical trials program included blinded, placebo-controlled dose ranging, efficacy in a variety of vascular beds (AIOD, renal, pedal), examination of potential drug interaction with warfarin and comparison with XRA. The clinical trials show that Vasovist-enhanced MR angiography is safe and well-tolerated in patients with vascular disease, effective for the detection of vascular stenosis and aneurysms, significantly more accurate (both more sensitive and specific) than non-contrast MR angiography for the diagnosis of vascular stenoses, and similar to conventional angiography for the overall characterization of vascular disease, without the need for catheterization. (orig.)

  2. Vasovist-enhanced MR angiography

    Energy Technology Data Exchange (ETDEWEB)

    Goyen, M. [Univ. Medical Center, Hamburg-Eppendorf, Hamburg (Germany); Shamsi, K. [Berlex Lab., Inc., Montville, NJ (United States); Schoenberg, S.O. [Dept. of Clinical Radiology, Univ. Hospitals Grosshadern, Munich (Germany)

    2006-02-15

    Vasovist (MS-325) is the first intravascular contrast agent approved for use with magnetic resonance angiography in the European Union. Vasovist reversibly binds to albumin, providing extended intravascular enhancement compared to existing extracellular magnetic resonance contrast agents. Prior to approval, Vasovist underwent extensive testing to evaluate the safety and efficacy of the drug; the clinical trials program included blinded, placebo-controlled dose ranging, efficacy in a variety of vascular beds (AIOD, renal, pedal), examination of potential drug interaction with warfarin and comparison with XRA. The clinical trials show that Vasovist-enhanced MR angiography is safe and well-tolerated in patients with vascular disease, effective for the detection of vascular stenosis and aneurysms, significantly more accurate (both more sensitive and specific) than non-contrast MR angiography for the diagnosis of vascular stenoses, and similar to conventional angiography for the overall characterization of vascular disease, without the need for catheterization. (orig.)

  3. Enhancing aquifer cleanup with reinjection

    International Nuclear Information System (INIS)

    Isherwood, W.F.; Ziagos, J.; Rice, D. Jr.; Krauter, P.; Nichols, E.

    1992-09-01

    Injection of water or steam, with or without chemical surfactants, is a common petroleum industry technique to enhance product recovery. In the geothermal industry, reinjection (reinjection is used to mean the injection of ground water that was previously injected) of heat- depleted subsurface fluids is commonly used to maintain reservoir pressure, thus prolonging field productivity. The use reinjection in ground-water remediation projects allows for the application of both traditional production field management and a variety of additional enhancements to the cleanup process. Development of the ideas in this paper was stimulated by an initial suggestion by Dr. Jacob Bear (personal discussions, 1990--1991) that reinjected water might be heated to aid the desorption process

  4. Gestures Enhance Foreign Language Learning

    Directory of Open Access Journals (Sweden)

    Manuela Macedonia

    2012-11-01

    Full Text Available Language and gesture are highly interdependent systems that reciprocally influence each other. For example, performing a gesture when learning a word or a phrase enhances its retrieval compared to pure verbal learning. Although the enhancing effects of co-speech gestures on memory are known to be robust, the underlying neural mechanisms are still unclear. Here, we summarize the results of behavioral and neuroscientific studies. They indicate that the neural representation of words consists of complex multimodal networks connecting perception and motor acts that occur during learning. In this context, gestures can reinforce the sensorimotor representation of a word or a phrase, making it resistant to decay. Also, gestures can favor embodiment of abstract words by creating it from scratch. Thus, we propose the use of gesture as a facilitating educational tool that integrates body and mind.

  5. Enhanced dilepton radiation at RHIC

    CERN Document Server

    Toia, Alberica

    2009-01-01

    Recently, there is growing evidence that a new state of matter is formed in Au+Au collisions at RHIC: a strongly coupled Quark Gluon Plasma of partonic degrees of freedom which develops a collective motion. Dilepton spectra are not affected by strong interaction and can therefore probe the whole time evolution of the collision. Thus they may be sensitive to the onset of deconfinement, chiral symmetry restoration, as well as the production of thermal photons. The PHENIX experiment measured the production of e+e− pairs in p+p and Au+Au collisions at . An enhanced dilepton yield in the mass range is measured. The excess increases faster with centrality than the number of participating nucleons, and is concentrated at . At higher pT the excess below 300 MeV/c2 has been related to an enhanced production of direct photons, possibly of thermal origin.

  6. Equipment improvements for performance enhancement

    International Nuclear Information System (INIS)

    Gaestel, P.; Guesnon, H.; Sauze, G.

    1994-01-01

    In order to enhance the reactor availability, several improvements on reactor equipment have been developed: design optimization for stator maintenance replacement in the main alternator; adjustment modification of stator coils in the main alternator for an easier maintenance; improvement of the fuel handling line (pole crane, transfer equipment, loading machine); development of a loose part trapping system in the steam generator secondary circuit. 1 tab

  7. Convection-enhanced water evaporation

    OpenAIRE

    B. M. Weon; J. H. Je; C. Poulard

    2011-01-01

    Water vapor is lighter than air; this can enhance water evaporation by triggering vapor convection but there is little evidence. We directly visualize evaporation of nanoliter (2 to 700 nL) water droplets resting on silicon wafer in calm air using a high-resolution dual X-ray imaging method. Temporal evolutions of contact radius and contact angle reveal that evaporation rate linearly changes with surface area, indicating convective (instead of diffusive) evaporation in nanoliter water droplet...

  8. Contrast-enhanced endoscopic ultrasonography

    DEFF Research Database (Denmark)

    Reddy, Nischita K; Ioncica, Ana Maria; Saftoiu, Adrian

    2011-01-01

    Contrast agents are increasingly being used to characterize the vasculature in an organ of interest, to better delineate benign from malignant pathology and to aid in staging and directing therapeutic procedures. We review the mechanisms of action of first, second and third generation contrast...... agents and their use in various endoscopic procedures in the gastrointestinal tract. Various applications of contrast-enhanced endoscopic ultrasonography include differentiating benign from malignant mediastinal lymphadenopathy, assessment of depth of invasion of esophageal, gastric and gall bladder...

  9. Closing thoughts for cognitive enhancement.

    Science.gov (United States)

    Kantak, Kathleen M; Wettstein, Joseph G

    2015-01-01

    The wide-ranging field of cognition enhancing research along with its ethics as it stands today is summarized. In the forefront are potentially novel drugs and non-pharmacological treatments for cognitive impairment across many different psychiatric and neurologic indications. Today's research will bring new drugs to patients tomorrow, and tomorrow's research will bring new molecular targets to clinical development that should be cognitive domain-specific. There is the likelihood that special populations may be better treated and that personalized medicine for cognitive impairment could become a reality. It is conceivable that with the current research effort, cognition enhancing drugs will become available to wide-ranging populations of people with neuropsychiatric illness and to those that are healthy. In some cultures, there is a push in society to be more intelligent or have more cognitive prowess. Thus, the ethical use of cognitive enhancing drugs should be an area of debate and communication. Neuroethics is a growing field and it intends to bring together key contributors such as physicians, disease experts, regulatory officials, and policy makers to discuss how such medicines can or should be made available. Together with this, one has to consider the possibility that no single medicine or technology will have a great impact on cognition and, therefore, combination therapy of drugs plus other approaches like exercise or transcranial direct-current stimulation may be the path forward. This is another area of scientific inquiry and debate, and the results should be fruitful and helpful to patients. The science of cognition is advancing at a rapid rate, and communication of its progress along with the development of rational and ethical policies for use of cognitive enhancers will be beneficial.

  10. Technology Education Professional Enhancement Project

    Science.gov (United States)

    Hughes, Thomas A., Jr.

    1996-01-01

    The two goals of this project are: the use of integrative field of aerospace technology to enhance the content and instruction delivered by math, science, and technology teachers through the development of a new publication entitled NASA Technology Today, and to develop a rationale and structure for the study of technology, which establishes the foundation for developing technology education standards and programs of the future.

  11. Enhanced photochemistry on metal surfaces

    International Nuclear Information System (INIS)

    Goncher, G.M.; Parsons, C.A.; Harris, C.B.

    1984-01-01

    Due to the fast relaxation of molecular excited states in the vicinity of a metal or semiconductor surface, few observations of surface photochemistry have been reported. The following work concerns the surface-enhanced photo-reactions of a variety of physisorbed molecules on roughened Ag surfaces. In summary, photodecomposition leads to a graphitic surface carbon product which is monitored via surface-enhanced Raman scattering. In most cases an initial two-photon molecular absorption step followed by further absorption and fragmentation is thought to occur. Enhancement of the incident fields occurs through roughness-mediated surface plasmon resonances. This mechanism provides the amplified electromagnetic surface fields responsible for the observed photodecomposition. The photodecomposition experiments are performed under ultra-high vacuum. Surface characterization of the roughened surfaces was done by Scanning Electron Microscopy (SEM), and electron-stimulated emission. The SEM revealed morphology on the order of 300-400 A. This size of roughness feature, when modelled as isolated spheres should exhibit the well-known Mie resonances for light of the correct wavelengths. For protrusions existing on a surface these Mie resonances can be thought of as a coupling of the light with the surface plasmon. Experimental verification of these resonances was provided by the electron-stimulated light emission results. These showed that a polished Ag surface emitted only the expected transition radiation at the frequency of the Ag bulk plasmon. Upon roughening, however, a broad range of lower frequencies extending well into the visible are seen from electron irradiation of the surface. Large enhancements are expected for those frequencies which are able to couple into the surface modes

  12. Plasmonics Enhanced Smartphone Fluorescence Microscopy

    KAUST Repository

    Wei, Qingshan; Acuna, Guillermo; Kim, Seungkyeum; Vietz, Carolin; Tseng, Derek; Chae, Jongjae; Shir, Daniel; Luo, Wei; Tinnefeld, Philip; Ozcan, Aydogan

    2017-01-01

    Smartphone fluorescence microscopy has various applications in point-of-care (POC) testing and diagnostics, ranging from e.g., quantification of immunoassays, detection of microorganisms, to sensing of viruses. An important need in smartphone-based microscopy and sensing techniques is to improve the detection sensitivity to enable quantification of extremely low concentrations of target molecules. Here, we demonstrate a general strategy to enhance the detection sensitivity of a smartphone-based fluorescence microscope by using surface-enhanced fluorescence (SEF) created by a thin metal-film. In this plasmonic design, the samples are placed on a silver-coated glass slide with a thin spacer, and excited by a laser-diode from the backside through a glass hemisphere, generating surface plasmon polaritons. We optimized this mobile SEF system by tuning the metal-film thickness, spacer distance, excitation angle and polarization, and achieved ~10-fold enhancement in fluorescence intensity compared to a bare glass substrate, which enabled us to image single fluorescent particles as small as 50 nm in diameter and single quantum-dots. Furthermore, we quantified the detection limit of this platform by using DNA origami-based brightness standards, demonstrating that ~80 fluorophores per diffraction-limited spot can be readily detected by our mobile microscope, which opens up new opportunities for POC diagnostics and sensing applications in resource-limited-settings.

  13. Field enhancement in plasmonic nanostructures

    Science.gov (United States)

    Piltan, Shiva; Sievenpiper, Dan

    2018-05-01

    Efficient generation of charge carriers from a metallic surface is a critical challenge in a wide variety of applications including vacuum microelectronics and photo-electrochemical devices. Replacing semiconductors with vacuum/gas as the medium of electron transport offers superior speed, power, and robustness to radiation and temperature. We propose a metallic resonant surface combining optical and electrical excitations of electrons and significantly reducing powers required using plasmon-induced enhancement of confined electric field. The properties of the device are modeled using the exact solution of the time-dependent Schrödinger equation at the barrier. Measurement results exhibit strong agreement with an analytical solution, and allow us to extract the field enhancement factor at the surface. Significant photocurrents are observed using combination of {{W}} {{{c}}{{m}}}-2 optical power and 10 V DC excitation on the surface. The model suggests optical field enhancement of 3 orders of magnitude at the metal interface due to plasmonic resonance. This simple planar structure provides valuable evidence on the electron emission mechanisms involved and it can be used for implementation of semiconductor compatible vacuum devices.

  14. Stochastic Capsule Endoscopy Image Enhancement

    Directory of Open Access Journals (Sweden)

    Ahmed Mohammed

    2018-06-01

    Full Text Available Capsule endoscopy, which uses a wireless camera to take images of the digestive tract, is emerging as an alternative to traditional colonoscopy. The diagnostic values of these images depend on the quality of revealed underlying tissue surfaces. In this paper, we consider the problem of enhancing the visibility of detail and shadowed tissue surfaces for capsule endoscopy images. Using concentric circles at each pixel for random walks combined with stochastic sampling, the proposed method enhances the details of vessel and tissue surfaces. The framework decomposes the image into two detailed layers that contain shadowed tissue surfaces and detail features. The target pixel value is recalculated for the smooth layer using similarity of the target pixel to neighboring pixels by weighting against the total gradient variation and intensity differences. In order to evaluate the diagnostic image quality of the proposed method, we used clinical subjective evaluation with a rank order on selected KID image database and compared it to state-of-the-art enhancement methods. The result showed that the proposed method provides a better result in terms of diagnostic image quality and objective quality contrast metrics and structural similarity index.

  15. Plasmonics Enhanced Smartphone Fluorescence Microscopy

    KAUST Repository

    Wei, Qingshan

    2017-05-12

    Smartphone fluorescence microscopy has various applications in point-of-care (POC) testing and diagnostics, ranging from e.g., quantification of immunoassays, detection of microorganisms, to sensing of viruses. An important need in smartphone-based microscopy and sensing techniques is to improve the detection sensitivity to enable quantification of extremely low concentrations of target molecules. Here, we demonstrate a general strategy to enhance the detection sensitivity of a smartphone-based fluorescence microscope by using surface-enhanced fluorescence (SEF) created by a thin metal-film. In this plasmonic design, the samples are placed on a silver-coated glass slide with a thin spacer, and excited by a laser-diode from the backside through a glass hemisphere, generating surface plasmon polaritons. We optimized this mobile SEF system by tuning the metal-film thickness, spacer distance, excitation angle and polarization, and achieved ~10-fold enhancement in fluorescence intensity compared to a bare glass substrate, which enabled us to image single fluorescent particles as small as 50 nm in diameter and single quantum-dots. Furthermore, we quantified the detection limit of this platform by using DNA origami-based brightness standards, demonstrating that ~80 fluorophores per diffraction-limited spot can be readily detected by our mobile microscope, which opens up new opportunities for POC diagnostics and sensing applications in resource-limited-settings.

  16. BNFL Magnox - Upgrades and enhancements

    International Nuclear Information System (INIS)

    Udbinac, M.J.

    2006-01-01

    In the past, generic models, restrictive budgets,and general shortages of resources have limited the scope of the UK's older Magnox simulators. Nevertheless, the simulators evolved slowly over time, becoming more like their reference plants, as resources became available. Three years ago, the Training and Development Branch of Magnox Electric plc took a giant leap, investing significant resources into the modernization of their training simulators. New hardware was built, including a new simulator room. The simulator software was ported from Unix running on outdated servers to new servers running Microsoft Windows NT. Perhaps most significantly, major model enhancements were made to key plant systems to significantly increase the likeness of each simulator to its reference plant. The upgrade to NT, the addition of state-of-the-art instructor stations, and some of the model enhancements were achieved with SimPort, an all-inclusive simulation package provided by DS and S. This paper will provide a more detailed view of the Magnox modular simulators, including how they are used and how they have benefited from the enhancements and upgrades implemented during the project. (author)

  17. Enhanced attention amplifies face adaptation.

    Science.gov (United States)

    Rhodes, Gillian; Jeffery, Linda; Evangelista, Emma; Ewing, Louise; Peters, Marianne; Taylor, Libby

    2011-08-15

    Perceptual adaptation not only produces striking perceptual aftereffects, but also enhances coding efficiency and discrimination by calibrating coding mechanisms to prevailing inputs. Attention to simple stimuli increases adaptation, potentially enhancing its functional benefits. Here we show that attention also increases adaptation to faces. In Experiment 1, face identity aftereffects increased when attention to adapting faces was increased using a change detection task. In Experiment 2, figural (distortion) face aftereffects increased when attention was increased using a snap game (detecting immediate repeats) during adaptation. Both were large effects. Contributions of low-level adaptation were reduced using free viewing (both experiments) and a size change between adapt and test faces (Experiment 2). We suggest that attention may enhance adaptation throughout the entire cortical visual pathway, with functional benefits well beyond the immediate advantages of selective processing of potentially important stimuli. These results highlight the potential to facilitate adaptive updating of face-coding mechanisms by strategic deployment of attentional resources. Copyright © 2011 Elsevier Ltd. All rights reserved.

  18. Threshold enhancement of diphoton resonances

    Directory of Open Access Journals (Sweden)

    Aoife Bharucha

    2016-10-01

    Full Text Available We revisit a mechanism to enhance the decay width of (pseudo-scalar resonances to photon pairs when the process is mediated by loops of charged fermions produced near threshold. Motivated by the recent LHC data, indicating the presence of an excess in the diphoton spectrum at approximately 750 GeV, we illustrate this threshold enhancement mechanism in the case of a 750 GeV pseudoscalar boson A with a two-photon decay mediated by a charged and uncolored fermion having a mass at the 12MA threshold and a small decay width, <1 MeV. The implications of such a threshold enhancement are discussed in two explicit scenarios: i the Minimal Supersymmetric Standard Model in which the A state is produced via the top quark mediated gluon fusion process and decays into photons predominantly through loops of charginos with masses close to 12MA and ii a two Higgs doublet model in which A is again produced by gluon fusion but decays into photons through loops of vector-like charged heavy leptons. In both these scenarios, while the mass of the charged fermion has to be adjusted to be extremely close to half of the A resonance mass, the small total widths are naturally obtained if only suppressed three-body decay channels occur. Finally, the implications of some of these scenarios for dark matter are discussed.

  19. [Lower is better: ENHANCE affair].

    Science.gov (United States)

    Scardi, Sabino; Umari, Paolo; D'Agata, Bianca Maria

    2008-06-01

    Ezetimibe lowers the intestinal absorption of cholesterol, being complementary to the effects of statin. To check its efficacy in lowering the carotid intima-media thickness, in 2002 a multicenter international trial called ENHANCE was started, in order to assess by ultrasound the regression of atherosclerotic plaques. The protocol tested the use of simvastatin 80 mg + placebo versus simvastatin 80 mg + ezetimibe 10 mg in 720 randomized patients. Both drugs were well tolerated. Combination therapy was associated with a larger reduction in LDL cholesterol, but there were no differences in the intima-media thickness measured at three sites in the carotid arteries, nor differences in cardiovascular events between the two groups in the trial. These results provoked disappointment of sponsors (Merck, Schering Plough) who, although the results of the trial were available since march 2007, delayed official communication of about 18 months. This led to speculations and rumors among media, American Government, cardiologic scientific associations, and consequences in the Ezetimibe market and at Wall Street. In particular, the American College of Cardiology didn't accept the communication of ENHANCE results to the Late Breaking Trial Session of the Chicago congress, diverting it to another secondary forum. In conclusion, the experience of the ENHANCE trial suggests to pharmaceutical companies, researchers, clinicians, scientific companies and media a deep meditation in order to avoid in the future similar problems in the management of results of medical research.

  20. Permeability enhancement by shock cooling

    Science.gov (United States)

    Griffiths, Luke; Heap, Michael; Reuschlé, Thierry; Baud, Patrick; Schmittbuhl, Jean

    2015-04-01

    The permeability of an efficient reservoir, e.g. a geothermal reservoir, should be sufficient to permit the circulation of fluids. Generally speaking, permeability decreases over the life cycle of the geothermal system. As a result, is usually necessary to artificially maintain and enhance the natural permeability of these systems. One of the methods of enhancement -- studied here -- is thermal stimulation (injecting cold water at low pressure). This goal of this method is to encourage new thermal cracks within the reservoir host rocks, thereby increasing reservoir permeability. To investigate the development of thermal microcracking in the laboratory we selected two granites: a fine-grained (Garibaldi Grey granite, grain size = 0.5 mm) and a course-grained granite (Lanhelin granite, grain size = 2 mm). Both granites have an initial porosity of about 1%. Our samples were heated to a range of temperatures (100-1000 °C) and were either cooled slowly (1 °C/min) or shock cooled (100 °C/s). A systematic microstructural (2D crack area density, using standard stereological techniques, and 3D BET specific surface area measurements) and rock physical property (porosity, P-wave velocity, uniaxial compressive strength, and permeability) analysis was undertaken to understand the influence of slow and shock cooling on our reservoir granites. Microstructurally, we observe that the 2D crack surface area per unit volume and the specific surface area increase as a result of thermal stressing, and, for the same maximum temperature, crack surface area is higher in the shock cooled samples. This observation is echoed by our rock physical property measurements: we see greater changes for the shock cooled samples. We can conclude that shock cooling is an extremely efficient method of generating thermal microcracks and modifying rock physical properties. Our study highlights that thermal treatments are likely to be an efficient method for the "matrix" permeability enhancement of

  1. Countermeasures to Enhance Sensorimotor Adaptability

    Science.gov (United States)

    Bloomberg, J. J.; Peters, B. T.; Mulavara, A. P.; Brady, R. A.; Batson, C. C.; Miller, C. A.; Cohen, H. S.

    2011-01-01

    During exploration-class missions, sensorimotor disturbances may lead to disruption in the ability to ambulate and perform functional tasks during the initial introduction to a novel gravitational environment following a landing on a planetary surface. The goal of our current project is to develop a sensorimotor adaptability (SA) training program to facilitate rapid adaptation to novel gravitational environments. We have developed a unique training system comprised of a treadmill placed on a motion-base facing a virtual visual scene that provides an unstable walking surface combined with incongruent visual flow designed to enhance sensorimotor adaptability. We have conducted a series of studies that have shown: Training using a combination of modified visual flow and support surface motion during treadmill walking enhances locomotor adaptability to a novel sensorimotor environment. Trained individuals become more proficient at performing multiple competing tasks while walking during adaptation to novel discordant sensorimotor conditions. Trained subjects can retain their increased level of adaptability over a six months period. SA training is effective in producing increased adaptability in a more complex over-ground ambulatory task on an obstacle course. This confirms that for a complex task like walking, treadmill training contains enough of the critical features of overground walking to be an effective training modality. The structure of individual training sessions can be optimized to promote fast/strategic motor learning. Training sessions that each contain short-duration exposures to multiple perturbation stimuli allows subjects to acquire a greater ability to rapidly reorganize appropriate response strategies when encountering a novel sensory environment. Individual sensory biases (i.e. increased visual dependency) can predict adaptive responses to novel sensory environments suggesting that customized training prescriptions can be developed to enhance

  2. Enhancing professionalism at GPU Nuclear

    International Nuclear Information System (INIS)

    Coe, R.P.

    1992-01-01

    Late in 1988, GPU Nuclear embarked on a major program aimed at enhancing professionalism at its Oyster Creek and Three Mile Island nuclear generating stations. The program was also to include its corporate headquarters in Parsippany, New Jersey. The overall program was to take several directions, including on-site degree programs, a sabbatical leave-type program for personnel to finish college degrees, advanced technical training for licensed staff, career progression for senior reactor operators, and expanded teamwork and leadership training for control room crew. The largest portion of this initiative was the development and delivery of professionalism training to the nearly 2,000 people at both nuclear generating sites

  3. Directing a Quality Enhancement Plan

    Directory of Open Access Journals (Sweden)

    Ronald A. Styron, Jr.

    2015-08-01

    Full Text Available This paper is drawn from a project aimed at enhancing the quality of instructional practice and improving studentlearning outcomes in classes across an urban university located in the southern region of the United States. The strategies, employed by the project leader, are discussed in detail as framed by a new problem-solving leadership design called the Alloy Improvement Model (AIM. Data collected at the end of the second full year and reported in this paper indicated all project goals were met and that the utilization of the AIM was central to project success.

  4. Enhanced candu 6 reactor: status

    International Nuclear Information System (INIS)

    Azeez, S.; Girouard, P.

    2006-01-01

    The CANDU 6 power reactor is visionary in its approach, renowned for its on-power refuelling capability and proven over years of safe, economical and reliable power production. Developed by Atomic Energy of Canada Limited (AECL), the CANDU 6 design offers excellent performance utilizing state-of-the-art technology. The first CANDU 6 plants went into service in the early 1980s as leading edge technology and the design has been continuously advanced to maintain superior performance with an outstanding safety record. The first set of CANDU 6 plants - Gentilly 2 and Point Lepreau in Canada, Embalse in Argentina and Wolsong- Unit 1 in Korea - have been in service for more than 22 years and are still producing electricity at peak performance; to the end of 2004, their average Lifetime Capacity Factor was 83.2%. The newer CANDU 6 units in Romania (Cernavoda 1), Korea (Wolsong-Units 2, 3 and 4) and Qinshan (Phase III- Units 1 and 2) have also been performing at outstanding levels. The average lifetime Capacity Factor of the 10 CANDU 6 operating units around the world has been 87% to the end of 2004. Building on these successes, AECL is committed to the further development of this highly successful design, now focussing on meeting customers' needs for reduced costs, further improvements to plant operation and performance, enhanced safety and incorporating up-to-date technology, as warranted. This has resulted in AECL embarking on improving the CANDU 6 design through an upgraded product termed the ''Enhanced CANDU 6'' (EC6), which incorporates several attractive but proven features that make the CANDU 6 reactor even more economical, safer and easier to operate. Some of the key features that are being incorporated into the EC6 include increasing the plant's power output, shortening the overall project schedule, decreasing the capital cost, dealing with obsolescence issues, optimizing maintenance outages and incorporating lessons learnt through feedback obtained from the

  5. Enhanced radiation resistant fiber optics

    International Nuclear Information System (INIS)

    Lyons, P.B.; Looney, L.D.

    1993-01-01

    A process for producing an optical fiber having enhanced radiation resistance is provided, the process including maintaining an optical fiber within a hydrogen-containing atmosphere for sufficient time to yield a hydrogen-permeated optical fiber having an elevated internal hydrogen concentration, and irradiating the hydrogen-permeated optical fiber at a time while the optical fiber has an elevated internal hydrogen concentration with a source of ionizing radiation. The radiation source is typically a cobalt-60 source and the fiber is pre-irradiated with a dose level up to about 1000 kilorads of radiation. 4 figures

  6. Enhancing implementation security of QKD

    Science.gov (United States)

    Tamaki, Kiyoshi

    2017-10-01

    Quantum key distribution (QKD) can achieve information-theoretic security, which is a provable security against any eavesdropping, given that all the devices the sender and the receiver employ operate exactly as the theory of security requires. Unfortunately, however, it is difficult for practical devices to meet all such requirements, and therefore more works have to be done toward guaranteeing information-theoretic security in practice, i.e., implementation security. In this paper, we review our recent efforts to enhance implementation security. We also have a brief look at a flaw in security proofs and present how to fix it.

  7. Performance Enhancement by Brain Stimulation

    Directory of Open Access Journals (Sweden)

    Parisa Gazerani

    2017-09-01

    Full Text Available Number of substances and strategies are available to increase performance in sport (Catlin and Murray, 1996. Since 2004, the World Anti-Doping Agency (WADA posts an updated list of substances and methods prohibited to athletes. Drugs (e.g., steroids, stimulants are a major part of this list; however, technologies and methods (e.g., gene doping are increasingly being identified and added (WADA, 2017. Among technologies and methods that might exert a potential effect on athletic performance, brain stimulation has recently been subjected to extensive discussion. Neuro-enhancement for doping purposes has been termed “neurodoping” in the literature (Davis, 2013; however, this concept needs further documentation before the term “neurodoping” can be used properly. Two major non-invasive techniques of brain stimulations are transcranial magnetic stimulation (TMS (Hallett, 2007; Rossi et al., 2009, and transcranial direct current stimulation (tDCS (Stagg and Nitsche, 2011. In TMS, an electric coil held over the head applies magnetic pulses to create currents in the brain. In tDCS, a low, continuous electrical current is delivered to the brain by using surface electrodes attached on the scalp. TMS and tDCS have been used in both research and clinic (Shin and Pelled, 2017 for example to examine alterations in cognitive function or motor skills or to assist in recovering motor function after a stroke (Gomez Palacio Schjetnan et al., 2013 or reducing fatigue in patients with multiple sclerosis (Saiote et al., 2014. In an opinion paper, it was proposed that use of emerging brain stimulation techniques might also enhance physical and mental performance in sports (Davis, 2013. The assumption was based on several reports. For example some studies have shown that TMS could shorten reaction times to visual, auditory and touch stimuli, reduce tremor, and enhance the acquisition of complex motor skills. Based on the current evidence, a recent review (Colzato

  8. Coherently Enhanced Wireless Power Transfer

    OpenAIRE

    Krasnok, Alex; Baranov, Denis G.; Generalov, Andrey; Li, Sergey; Alu, Andrea

    2017-01-01

    Extraction of electromagnetic energy by an antenna from impinging external radiation is at the basis of wireless communications and power transfer (WPT). The maximum of transferred energy is ensured when the antenna is conjugately matched, i.e., when it is resonant and it has an equal coupling with free space and its load, which is not easily implemented in near-field WPT. Here, we introduce the concept of coherently enhanced wireless power transfer. We show that a principle similar to the on...

  9. Image analysis enhancement and interpretation

    International Nuclear Information System (INIS)

    Glauert, A.M.

    1978-01-01

    The necessary practical and mathematical background are provided for the analysis of an electron microscope image in order to extract the maximum amount of structural information. Instrumental methods of image enhancement are described, including the use of the energy-selecting electron microscope and the scanning transmission electron microscope. The problems of image interpretation are considered with particular reference to the limitations imposed by radiation damage and specimen thickness. A brief survey is given of the methods for producing a three-dimensional structure from a series of two-dimensional projections, although emphasis is really given on the analysis, processing and interpretation of the two-dimensional projection of a structure. (Auth.)

  10. Enhanced radiation resistant fiber optics

    Science.gov (United States)

    Lyons, P.B.; Looney, L.D.

    1993-11-30

    A process for producing an optical fiber having enhanced radiation resistance is provided, the process including maintaining an optical fiber within a hydrogen-containing atmosphere for sufficient time to yield a hydrogen-permeated optical fiber having an elevated internal hydrogen concentration, and irradiating the hydrogen-permeated optical fiber at a time while the optical fiber has an elevated internal hydrogen concentration with a source of ionizing radiation. The radiation source is typically a cobalt-60 source and the fiber is pre-irradiated with a dose level up to about 1000 kilorads of radiation. 4 figures.

  11. Enhanced Master Controller Unit Tester

    Science.gov (United States)

    Benson, Patricia; Johnson, Yvette; Johnson, Brian; Williams, Philip; Burton, Geoffrey; McCoy, Anthony

    2007-01-01

    The Enhanced Master Controller Unit Tester (EMUT) software is a tool for development and testing of software for a master controller (MC) flight computer. The primary function of the EMUT software is to simulate interfaces between the MC computer and external analog and digital circuitry (including other computers) in a rack of equipment to be used in scientific experiments. The simulations span the range of nominal, off-nominal, and erroneous operational conditions, enabling the testing of MC software before all the equipment becomes available.

  12. ICT applications enhancing energy efficiency

    Directory of Open Access Journals (Sweden)

    A. G. Matani

    2016-06-01

    Full Text Available Computers, laptops and mobile devices – information technology (IT accounts for 2% of human greenhouse gas emissions worldwide, as evidenced in a study by Global Action Plan, a UK based environmental organization. This figure can be reduced if the green segment, or Green IT, continues to grow. Energy can also be saved through cloud computing, namely the principle of outsourcing the programs and functions of one’s own computer to service providers over the internet. This also means sharing storage capacity with others. This paper highlights the impact of information technology applications towards enhancing energy efficiency of the systems.

  13. DENdb: database of integrated human enhancers

    KAUST Repository

    Ashoor, Haitham

    2015-09-05

    Enhancers are cis-acting DNA regulatory regions that play a key role in distal control of transcriptional activities. Identification of enhancers, coupled with a comprehensive functional analysis of their properties, could improve our understanding of complex gene transcription mechanisms and gene regulation processes in general. We developed DENdb, a centralized on-line repository of predicted enhancers derived from multiple human cell-lines. DENdb integrates enhancers predicted by five different methods generating an enriched catalogue of putative enhancers for each of the analysed cell-lines. DENdb provides information about the overlap of enhancers with DNase I hypersensitive regions, ChIP-seq regions of a number of transcription factors and transcription factor binding motifs, means to explore enhancer interactions with DNA using several chromatin interaction assays and enhancer neighbouring genes. DENdb is designed as a relational database that facilitates fast and efficient searching, browsing and visualization of information.

  14. DENdb: database of integrated human enhancers

    KAUST Repository

    Ashoor, Haitham; Kleftogiannis, Dimitrios A.; Radovanovic, Aleksandar; Bajic, Vladimir B.

    2015-01-01

    Enhancers are cis-acting DNA regulatory regions that play a key role in distal control of transcriptional activities. Identification of enhancers, coupled with a comprehensive functional analysis of their properties, could improve our understanding of complex gene transcription mechanisms and gene regulation processes in general. We developed DENdb, a centralized on-line repository of predicted enhancers derived from multiple human cell-lines. DENdb integrates enhancers predicted by five different methods generating an enriched catalogue of putative enhancers for each of the analysed cell-lines. DENdb provides information about the overlap of enhancers with DNase I hypersensitive regions, ChIP-seq regions of a number of transcription factors and transcription factor binding motifs, means to explore enhancer interactions with DNA using several chromatin interaction assays and enhancer neighbouring genes. DENdb is designed as a relational database that facilitates fast and efficient searching, browsing and visualization of information.

  15. Enhancing Rotational Diffusion Using Oscillatory Shear

    KAUST Repository

    Leahy, Brian D.; Cheng, Xiang; Ong, Desmond C.; Liddell-Watson, Chekesha; Cohen, Itai

    2013-01-01

    Taylor dispersion - shear-induced enhancement of translational diffusion - is an important phenomenon with applications ranging from pharmacology to geology. Through experiments and simulations, we show that rotational diffusion is also enhanced

  16. Complementary surface charge for enhanced capacitive deionization

    NARCIS (Netherlands)

    Gao, X.; Porada, S.; Omosebi, A.; Liu, K.L.; Biesheuvel, P.M.; Landon, J.

    2016-01-01

    Commercially available activated carbon cloth electrodes are treated using nitric acid and ethylenediamine solutions, resulting in chemical surface charge enhanced carbon electrodes for capacitive deionization (CDI) applications. Surface charge enhanced electrodes are then configured in a CDI

  17. Analyzing Security-Enhanced Linux Policy Specifications

    National Research Council Canada - National Science Library

    Archer, Myla

    2003-01-01

    NSA's Security-Enhanced (SE) Linux enhances Linux by providing a specification language for security policies and a Flask-like architecture with a security server for enforcing policies defined in the language...

  18. Enhanced localized fluorescence in plasmonic nanoantennae

    DEFF Research Database (Denmark)

    Bakker, R.M.; Yuan, H.-K.; Liu, Z.

    2008-01-01

    in fluorescence that reaches 100 times enhancement. Near-field excitation shows enhanced fluorescence from a single nanoantenna localized in a subwavelength area of similar to 0.15 mu m(2). The polarization of enhanced emission is along the main antenna axis. These observed experimental results are important...

  19. Textual Enhancement of Input: Issues and Possibilities

    Science.gov (United States)

    Han, ZhaoHong; Park, Eun Sung; Combs, Charles

    2008-01-01

    The input enhancement hypothesis proposed by Sharwood Smith (1991, 1993) has stimulated considerable research over the last 15 years. This article reviews the research on textual enhancement of input (TE), an area where the majority of input enhancement studies have aggregated. Methodological idiosyncrasies are the norm of this body of research.…

  20. Chemical Penetration Enhancers for Transdermal Drug Delivery ...

    African Journals Online (AJOL)

    for transdermal administration. The permeation of drug through skin can be enhanced by both chemical penetration enhancement and physical methods. In this review, we have discussed the chemical penetration enhancement technology for transdermal drug delivery as well as the probable mechanisms of action.

  1. Enhancing poxvirus vectors vaccine immunogenicity.

    Science.gov (United States)

    García-Arriaza, Juan; Esteban, Mariano

    2014-01-01

    Attenuated recombinant poxvirus vectors expressing heterologous antigens from pathogens are currently at various stages in clinical trials with the aim to establish their efficacy. This is because these vectors have shown excellent safety profiles, significant immunogenicity against foreign expressed antigens and are able to induce protective immune responses. In view of the limited efficacy triggered by some poxvirus strains used in clinical trials (i.e, ALVAC in the RV144 phase III clinical trial for HIV), and of the restrictive replication capacity of the highly attenuated vectors like MVA and NYVAC, there is a consensus that further improvements of these vectors should be pursuit. In this review we considered several strategies that are currently being implemented, as well as new approaches, to improve the immunogenicity of the poxvirus vectors. This includes heterologous prime/boost protocols, use of co-stimulatory molecules, deletion of viral immunomodulatory genes still present in the poxvirus genome, enhancing virus promoter strength, enhancing vector replication capacity, optimizing expression of foreign heterologous sequences, and the combined use of adjuvants. An optimized poxvirus vector triggering long-lasting immunity with a high protective efficacy against a selective disease should be sought.

  2. Enhancement of confinement in tokamaks

    International Nuclear Information System (INIS)

    Furth, H.P.

    1986-05-01

    A plausible interpretation of the experimental evidence is that energy confinement in tokamaks is governed by two separate considerations: (1) the need for resistive MHD kink-stability, which limits the permissible range of current profiles - and therefore normally also the range of temperature profiles; and (2) the presence of strongly anomalous microscopic energy transport near the plasma edge, which calibrates the amplitude of the global temperature profile, thus determining the energy confinement time tau/sub E/. Correspondingly, there are two main paths towards the enhancement of tokamak confinement: (1) Configurational optimization, to increase the MHD-stable energy content of the plasma core, can evidently be pursued by varying the cross-sectional shape of the plasma and/or finding stable radial profiles with central q-values substantially below unity - but crossing from ''first'' to ''second'' stability within the peak-pressure region would have the greatest ultimate potential. (2) Suppression of edge turbulence, so as to improve the heat insulation in the outer plasma shell, can be pursued by various local stabilizing techniques, such as use of a poloidal divertor. The present confinement model and initial TFTR pellet-injection results suggest that the introduction of a super-high-density region within the plasma core should be particularly valuable for enhancing ntau/subE/. In D-T operation, a centrally peaked plasma pressure profile could possibly lend itself to alpha-particle-driven entry into the second-stability regime

  3. Enhancing protection for vulnerable waters

    Science.gov (United States)

    Creed, Irena F.; Lane, Charles R.; Serran, Jacqueline N.; Alexander, Laurie C.; Basu, Nandita B.; Calhoun, Aram J. K.; Christensen, Jay R.; Cohen, Matthew J.; Craft, Christopher; D'Amico, Ellen; Dekeyser, Edward; Fowler, Laurie; Golden, Heather E.; Jawitz, James W.; Kalla, Peter; Kirkman, L. Katherine; Lang, Megan; Leibowitz, Scott G.; Lewis, David B.; Marton, John; McLaughlin, Daniel L.; Raanan-Kiperwas, Hadas; Rains, Mark C.; Rains, Kai C.; Smith, Lora

    2017-11-01

    Governments worldwide do not adequately protect their limited freshwater systems and therefore place freshwater functions and attendant ecosystem services at risk. The best available scientific evidence compels enhanced protections for freshwater systems, especially for impermanent streams and wetlands outside of floodplains that are particularly vulnerable to alteration or destruction. New approaches to freshwater sustainability -- implemented through scientifically informed adaptive management -- are required to protect freshwater systems through periods of changing societal needs. One such approach introduced in the US in 2015 is the Clean Water Rule, which clarified the jurisdictional scope for federally protected waters. However, within hours of its implementation litigants convinced the US Court of Appeals for the Sixth Circuit to stay the rule, and the subsequently elected administration has now placed it under review for potential revision or rescission. Regardless of its outcome at the federal level, policy and management discussions initiated by the propagation of this rare rulemaking event have potential far-reaching implications at all levels of government across the US and worldwide. At this timely juncture, we provide a scientific rationale and three policy options for all levels of government to meaningfully enhance protection of these vulnerable waters. A fourth option, a 'do-nothing' approach, is wholly inconsistent with the well-established scientific evidence of the importance of these vulnerable waters.

  4. ENPEP model enhancements at ANL

    International Nuclear Information System (INIS)

    Guziel, K.A.

    1997-01-01

    Argonne National Laboratory (ANL) has been involved in energy and electricity planning analyses for almost 20 years. Their activities include the development of analytical tools and methodologies along with their application to a wide variety of national energy planning studies. The methodologies cover all aspects of energy planning. In response to a request by the US Department of Energy (USDOE) to integrate existing tools into a package that could be distributed to developing countries for their own use, the ENergy and Power Evaluation Program (ENPEP) was developed. The USDOE wanted an all purpose tool that would allow the user to do a complete energy analysis, from demand forecast through primary energy resources allocation to electricity generation system expansion plan and environmental analysis. Since its original development, the ENPEP modules have been improved and enhanced to incorporate advancements in computer hardware and software technology, as well as to correct bugs that were identified in the programs. In cooperation with other organizations (e.g. The World Bank - IBRD - and the International Atomic Energy Agency - IAEA -), the ENPEP package has been used at national, regional and inter-regional training courses, as well as in the conduct of national energy/electricity planning studies. This paper reviews the development of the ENPEP package and the proposed enhancements to the package. (author). 1 fig., 2 tabs

  5. Potential MCNP enhancements for NCT

    International Nuclear Information System (INIS)

    Estes, G.P.; Taylor, W.M.

    1992-01-01

    MCNP a Monte Carlo radiation transport code, is currently widely used in the medical community for a variety of purposes including treatment planning, diagnostics, beam design, tomographic studies, and radiation protection. This is particularly true in the Neutron Capture Therapy (NCT) community. The current widespread medical use of MCNP after its general public distribution in about 1980 attests to the code's general versatility and usefulness, particularly since its development to date has not been influenced by medical applications. This paper discusses enhancements to MCNP that could be implemented at Los Alamos for the benefit of the NCT community. These enhancements generally fall into two categories, namely those that have already been developed to some extent but are not yet publicly available, and those that seem both needed based on our current understanding of NCT goals, and achievable based on our working knowledge of the MCNP code. MCNP is a general, coupled neutron/photon/electron Monte Carlo code developed and maintained by the Radiation Transport Group at Los Alamos. It has been used extensively for radiation shielding studies, reactor analysis, detector design, physics experiment interpretation, oil and gas well logging, radiation protection studies, accelerator design, etc. over the years. MCNP is a three-dimensional geometry, continuous energy physics code capable of modeling complex geometries, specifying material regions such as organs by the intersections of analytical surfaces

  6. Defense mutualisms enhance plant diversification.

    Science.gov (United States)

    Weber, Marjorie G; Agrawal, Anurag A

    2014-11-18

    The ability of plants to form mutualistic relationships with animal defenders has long been suspected to influence their evolutionary success, both by decreasing extinction risk and by increasing opportunity for speciation through an expanded realized niche. Nonetheless, the hypothesis that defense mutualisms consistently enhance plant diversification across lineages has not been well tested due to a lack of phenotypic and phylogenetic information. Using a global analysis, we show that the >100 vascular plant families in which species have evolved extrafloral nectaries (EFNs), sugar-secreting organs that recruit arthropod mutualists, have twofold higher diversification rates than families that lack species with EFNs. Zooming in on six distantly related plant clades, trait-dependent diversification models confirmed the tendency for lineages with EFNs to display increased rates of diversification. These results were consistent across methodological approaches. Inference using reversible-jump Markov chain Monte Carlo (MCMC) to model the placement and number of rate shifts revealed that high net diversification rates in EFN clades were driven by an increased number of positive rate shifts following EFN evolution compared with sister clades, suggesting that EFNs may be indirect facilitators of diversification. Our replicated analysis indicates that defense mutualisms put lineages on a path toward increased diversification rates within and between clades, and is concordant with the hypothesis that mutualistic interactions with animals can have an impact on deep macroevolutionary patterns and enhance plant diversity.

  7. Is caffeine a cognitive enhancer?

    Science.gov (United States)

    Nehlig, Astrid

    2010-01-01

    The effects of caffeine on cognition were reviewed based on the large body of literature available on the topic. Caffeine does not usually affect performance in learning and memory tasks, although caffeine may occasionally have facilitatory or inhibitory effects on memory and learning. Caffeine facilitates learning in tasks in which information is presented passively; in tasks in which material is learned intentionally, caffeine has no effect. Caffeine facilitates performance in tasks involving working memory to a limited extent, but hinders performance in tasks that heavily depend on working memory, and caffeine appears to rather improve memory performance under suboptimal alertness conditions. Most studies, however, found improvements in reaction time. The ingestion of caffeine does not seem to affect long-term memory. At low doses, caffeine improves hedonic tone and reduces anxiety, while at high doses, there is an increase in tense arousal, including anxiety, nervousness, jitteriness. The larger improvement of performance in fatigued subjects confirms that caffeine is a mild stimulant. Caffeine has also been reported to prevent cognitive decline in healthy subjects but the results of the studies are heterogeneous, some finding no age-related effect while others reported effects only in one sex and mainly in the oldest population. In conclusion, it appears that caffeine cannot be considered a ;pure' cognitive enhancer. Its indirect action on arousal, mood and concentration contributes in large part to its cognitive enhancing properties.

  8. Enhancing managerial effectiveness in dietetics.

    Science.gov (United States)

    Hoover, L W

    1983-01-01

    Environmental pressures from such sources as economic conditions, the government, third-party payers, and inter-institutional competition create managerial challenges. Although cost-containment has received considerable attention, long-term cost-effectiveness is probably the significant issue. Dietitians must become more cost-conscious and effective in resource management to attain desired performance outcomes. Some of the skills and characteristics essential to managerial effectiveness are a marketing orientation, systems design skill, quantitative operations management techniques, financial expertise, and leadership. These abilities facilitate decision-making and achievement of long-term cost-effectiveness. Curriculum enhancement and continuing education are two strategies for improving managerial competency in the dietetics profession. In dietetics education, study of management topics should be enhanced to provide more advanced coverage of management theories and quantitative models so that managerial performance can be at a higher level of sophistication and competency. To assure the viability of the dietetics profession, the emphasis on management must be more comprehensive and rigorous.

  9. Enhanced oil recovery program review

    International Nuclear Information System (INIS)

    1994-05-01

    Canada accounts for 40% of the global resources in heavy oils and oil sands bitumen, however, more than 90% of these resources need new and innovative technologies if they are to be made available at a competitive price. CANMET's Enhanced Oil Recovery (EOR) program was created in the late 1970s in response to the drive for energy self-sufficiency. Funding of the project is highly leveraged; industry funding towards projects supported under the CANMET Energy Conversion Program averaged over 300% annually since the previous review in 1990. Multi-client EOR technology projects include horizontal well technology, development of the vapour extraction process, and field testing of oil sands extraction technology. Direction and priorities of the program are established in consultation with the Minister's Advisory Council to CANMET (MNACC), industry and other performers and sponsors of enhanced oil recovery R and D. This review, including client feedback from interviews with several industry spokespersons, concluded that the program was well managed, and of high priority. Various options capable of meeting future needs were examined. Continuation of the current program, incorporating a number of significant changes, was recommended

  10. Threshold enhancement of diphoton resonances

    CERN Document Server

    Bharucha, Aoife; Goudelis, Andreas

    2016-10-10

    The data collected by the LHC collaborations at an energy of 13 TeV indicates the presence of an excess in the diphoton spectrum that would correspond to a resonance of a 750 GeV mass. The apparently large production cross section is nevertheless very difficult to explain in minimal models. We consider the possibility that the resonance is a pseudoscalar boson $A$ with a two--photon decay mediated by a charged and uncolored fermion having a mass at the $\\frac12 M_A$ threshold and a very small decay width, $\\ll 1$ MeV; one can then generate a large enhancement of the $A\\gamma\\gamma$ amplitude which explains the excess without invoking a large multiplicity of particles propagating in the loop, large electric charges and/or very strong Yukawa couplings. The implications of such a threshold enhancement are discussed in two explicit scenarios: i) the Minimal Supersymmetric Standard Model in which the $A$ state is produced via the top quark mediated gluon fusion process and decays into photons predominantly through...

  11. ENPEP model enhancements at ANL

    Energy Technology Data Exchange (ETDEWEB)

    Guziel, K A [Decision and Information Sciences Div., Argonne National Lab., Argonne, IL (United States)

    1997-09-01

    Argonne National Laboratory (ANL) has been involved in energy and electricity planning analyses for almost 20 years. Their activities include the development of analytical tools and methodologies along with their application to a wide variety of national energy planning studies. The methodologies cover all aspects of energy planning. In response to a request by the US Department of Energy (USDOE) to integrate existing tools into a package that could be distributed to developing countries for their own use, the ENergy and Power Evaluation Program (ENPEP) was developed. The USDOE wanted an all purpose tool that would allow the user to do a complete energy analysis, from demand forecast through primary energy resources allocation to electricity generation system expansion plan and environmental analysis. Since its original development, the ENPEP modules have been improved and enhanced to incorporate advancements in computer hardware and software technology, as well as to correct bugs that were identified in the programs. In cooperation with other organizations (e.g. The World Bank - IBRD - and the International Atomic Energy Agency - IAEA -), the ENPEP package has been used at national, regional and inter-regional training courses, as well as in the conduct of national energy/electricity planning studies. This paper reviews the development of the ENPEP package and the proposed enhancements to the package. (author). 1 fig., 2 tabs.

  12. Plasmonic enhancement of ultraviolet fluorescence

    Science.gov (United States)

    Jiao, Xiaojin

    Plasmonics relates to the interaction between electromagnetic radiation and conduction electrons at metallic interfaces or in metallic nanostructures. Surface plasmons are collective electron oscillations at a metal surface, which can be manipulated by shape, texture and material composition. Plasmonic applications cover a broad spectrum from visible to near infrared, including biosensing, nanolithography, spectroscopy, optoelectronics, photovoltaics and so on. However, there remains a gap in this activity in the ultraviolet (UV, research. Motivating factors in the study of UV Plasmonics are the direct access to biomolecular resonances and native fluorescence, resonant Raman scattering interactions, and the potential for exerting control over photochemical reactions. This dissertation aims to fill in the gap of Plasmonics in the UV with efforts of design, fabrication and characterization of aluminium (Al) and magnesium (Mg) nanostructures for the application of label-free bimolecular detection via native UV fluorescence. The first contribution of this dissertation addresses the design of Al nanostructures in the context of UV fluorescence enhancement. A design method that combines analytical analysis with numerical simulation has been developed. Performance of three canonical plasmonic structures---the dipole antenna, bullseye nanoaperture and nanoaperture array---has been compared. The optimal geometrical parameters have been determined. A novel design of a compound bullseye structure has been proposed and numerically analyzed for the purpose of compensating for the large Stokes shift typical of UV fluorescence. Second, UV lifetime modification of diffusing molecules by Al nanoapertures has been experimentally demonstrated for the first time. Lifetime reductions of ~3.5x have been observed for the high quantum yield (QY) laser dye p-terphenyl in a 60 nm diameter aperture with 50 nm undercut. Furthermore, quantum-yield-dependence of lifetime reduction has been

  13. Post Fukushima safety enhancements in Indian PHWRS

    International Nuclear Information System (INIS)

    Ramasomayajulu, M.; Khot, Pankaj; Chauhan, Ashok

    2016-01-01

    Fukushima event was reviewed in Nuclear Power Corporation of India (NPCIL) and based on these reviews, safety enhancements were identified for Indian PHWRs. Safety enhancements such as additional emergency power sources, enhanced onsite water inventories, external water injection arrangements (Hook up points), measures related to hydrogen management, containment venting provision, seismic trip, mobile pumps, onsite emergency support Centre. These safety enhancements were reviewed by the regulatory body (Atomic Energy Regulatory Board, AERB) and were approved for implementation. Most of these are either implemented or in the advance stage of implementation. The paper elaborates above safety enhancements implemented post Fukushima accident; and preparedness to use these provisions. (author)

  14. Meningeal enhancement on MRI after craniotomy

    International Nuclear Information System (INIS)

    Nomura, Motohiro; Hasegawa, Mitsuhiro; Yamashima, Tetsumori; Yamashita, Junkoh; Suzuki, Masayuki

    1991-01-01

    Gd-DPTA-enhanced MR images in 94 patients who had undergone craniotomy were studied, with particular attention paid to the meningeal enhancement. Such enhancement was noted in 26 of the 94 (27.6%) in the portion surrounding the craniotomy site. Meningeal enhancement, presumably of the subdural neomembrane, was apparent as a third line of a high signal intensity on T 1 -weighted MR images. The outer two high-intensity lines were derived from fat in the subcutaneous tissues of the scalp and fat in the bone marrow of the calvaria. We designated this characteristic enhancement as a 'triple white line'. Of the 26 patients with meningeal enhancement, 22 cases (23.4%) showed such a 'triple white line', 11 cases (11.7%) showed falx enhancement, and 12 cases (12.8%) showed tentorial enhancement. The intervals between surgery and the appearance of the meningeal enhancement ranged from 4 days to 88 weeks. A small amount of bleeding into the dura-arachnoid interface induced by surgery might result in the subdural neomembrane, as has previously been reported. This neomembrane might be enhanced by the leakage of Gd-DTPA through the proliferating capillaries. As meningeal enhancement occurs in approximately a third of the cases following craniotomy, much care should be taken in the differential diagnosis of the infection, inflammation, and metastasis or dissemination of malignant brain tumors. (author)

  15. Metal-enhanced fluorescence exciplex emission.

    Science.gov (United States)

    Zhang, Yongxia; Mali, Buddha L; Geddes, Chris D

    2012-01-01

    In this letter, we report the first observation of metal-enhanced exciplex fluorescence, observed from anthracene in the presence of diethylaniline. Anthracene in the presence of diethylaniline in close proximity to Silver Island Films (SIFs) shows enhanced monomer and exciplex emission as compared to a non-silvered control sample containing no silver nanoparticles. Our findings suggest two complementary methods for the enhancement: (i) surface plasmons can radiate coupled monomer and exciplex fluorescence efficiently, and (ii) enhanced absorption (enhanced electric near-field) further facilitates enhanced emission. Our exciplex studies help us to further understand the complex photophysics of the metal-enhanced fluorescence technology. Copyright © 2011 Elsevier B.V. All rights reserved.

  16. Enhanced Raman scattering in porous silicon grating.

    Science.gov (United States)

    Wang, Jiajia; Jia, Zhenhong; Lv, Changwu

    2018-03-19

    The enhancement of Raman signal on monocrystalline silicon gratings with varying groove depths and on porous silicon grating were studied for a highly sensitive surface enhanced Raman scattering (SERS) response. In the experiment conducted, porous silicon gratings were fabricated. Silver nanoparticles (Ag NPs) were then deposited on the porous silicon grating to enhance the Raman signal of the detective objects. Results show that the enhancement of Raman signal on silicon grating improved when groove depth increased. The enhanced performance of Raman signal on porous silicon grating was also further improved. The Rhodamine SERS response based on Ag NPs/ porous silicon grating substrates was enhanced relative to the SERS response on Ag NPs/ porous silicon substrates. Ag NPs / porous silicon grating SERS substrate system achieved a highly sensitive SERS response due to the coupling of various Raman enhancement factors.

  17. Enhancing autonomy in paid surrogacy.

    Science.gov (United States)

    Damelio, Jennifer; Sorensen, Kelly

    2008-06-01

    The gestational surrogate--and her economic and educational vulnerability in particular--is the focus of many of the most persistent worries about paid surrogacy. Those who employ her, and those who broker and organize her services, usually have an advantage over her in resources and information. That asymmetry exposes her to the possibility of exploitation and abuse. Accordingly, some argue for banning paid surrogacy. Others defend legal permission on grounds of surrogate autonomy, but often retain concerns about the surrogate. In response to the dilemma of a ban versus bald permission, we propose a 'soft law' approach: states should require several hours of education of surrogates--education aimed at informing and enhancing surrogate autonomy.

  18. Photosynthesis solutions to enhance productivity.

    Science.gov (United States)

    Foyer, Christine H; Ruban, Alexander V; Nixon, Peter J

    2017-09-26

    The concept that photosynthesis is a highly inefficient process in terms of conversion of light energy into biomass is embedded in the literature. It is only in the past decade that the processes limiting photosynthetic efficiency have been understood to an extent that allows a step change in our ability to manipulate light energy assimilation into carbon gain. We can therefore envisage that future increases in the grain yield potential of our major crops may depend largely on increasing the efficiency of photosynthesis. The papers in this issue provide new insights into the nature of current limitations on photosynthesis and identify new targets that can be used for crop improvement, together with information on the impacts of a changing environment on the productivity of photosynthesis on land and in our oceans.This article is part of the themed issue 'Enhancing photosynthesis in crop plants: targets for improvement'. © 2017 The Author(s).

  19. Enhanced performance hybrid-arq

    KAUST Repository

    Fareed, Muhammad Mehboob

    2016-06-16

    Apparatuses, computer readable media, and methods are provided for enhancing hybrid automatic repeat request (ARQ) performance. In an example method, a communication device transmits a first element of a vector, where the vector is selected using the information bits to be transmitted as an index in a code book. In some embodiments, this code book is constructed using Linear Constellation Precoding (LCP). If a NACK is received, the communication device transmits a second element of the vector. The process of transmitting elements of the vector continues until an ACK is received or the maximum number of transmission attempts is reached. If an ACK is received, the communication device transmits a first element of another vector of the code book that encodes a second set of information bits. This procedure may continue until all information bits have been transmitted successfully.

  20. Research for enhancing reactor safety

    International Nuclear Information System (INIS)

    1989-05-01

    Recent research for enhanced reactor safety covers extensive and numerous experiments and computed modelling activities designed to verify and to improve existing design requirements. The lectures presented at the meeting report GRS research results and the current status of reactor safety research in France. The GRS experts present results concerning expert systems and their perspectives in safety engineering, large-scale experiments and their significance in the development and verification of computer codes for thermohydraulic modelling of safety-related incidents, the advanced system code ATHLET for analysis of thermohydraulic processes of incidents, the analysis simulator which is a tool for fast evaluation of accident management measures, and investigations into event sequences and the required preventive emergency measures within the German Risk Study. (DG) [de

  1. The Game Enhanced Learning Model

    DEFF Research Database (Denmark)

    Reng, Lars; Schoenau-Fog, Henrik

    2016-01-01

    will describe the levels of the model, which is based on our experience in teaching professional game development at university level. Furthermore, we have been using the model to inspire numerous educators to improve their students’ motivation and skills. The model presents various game-based learning...... activities, and depicts their required planning and expected outcome through eight levels. At its lower levels, the model contains the possibilities of using stand-alone analogue and digital games as teachers, utilizing games as a facilitator of learning activities, exploiting gamification and motivating......In this paper, we will introduce the Game Enhanced learning Model (GEM), which describes a range of gameoriented learning activities. The model is intended to give an overview of the possibilities of game-based learning in general and all the way up to purposive game productions. In the paper, we...

  2. Enhanced performance hybrid-arq

    KAUST Repository

    Fareed, Muhammad Mehboob; Yang, Hong-Chuan; Alouini, Mohamed-Slim

    2016-01-01

    Apparatuses, computer readable media, and methods are provided for enhancing hybrid automatic repeat request (ARQ) performance. In an example method, a communication device transmits a first element of a vector, where the vector is selected using the information bits to be transmitted as an index in a code book. In some embodiments, this code book is constructed using Linear Constellation Precoding (LCP). If a NACK is received, the communication device transmits a second element of the vector. The process of transmitting elements of the vector continues until an ACK is received or the maximum number of transmission attempts is reached. If an ACK is received, the communication device transmits a first element of another vector of the code book that encodes a second set of information bits. This procedure may continue until all information bits have been transmitted successfully.

  3. Unrequited: neurochemical enhancement of love.

    Science.gov (United States)

    Bamford, Rebecca

    2015-07-01

    I raise several concerns with Earp and colleagues' analysis of enhancement through neurochemical modulation of love as a key issue in contemporary neuroethics. These include: (i) strengthening their deflation of medicalization concerns by showing how the objection that love should be left outside of the scope of medicine would directly undermine the goal of medicine; (ii) developing stronger analysis of the social and political concerns relevant to neurochemical modulation of love, by exploring and suggesting possible counters to ways in which 'wellbeing' may be used as a tool of oppression; (iii) providing reasons to support a broad need for ecological investigation of, and indeed ecological education concerning, neurotechnology; (iv) suggesting ways in which philosophy, and the humanities more broadly, remain directly relevant to responding effectively to issues in contemporary neuroethics.

  4. Contrast-enhanced endoscopic ultrasonography

    DEFF Research Database (Denmark)

    Reddy, Nischita K; Ioncică, Ana Maria; Săftoiu, Adrian

    2011-01-01

    Contrast agents are increasingly being used to characterize the vasculature in an organ of interest, to better delineate benign from malignant pathology and to aid in staging and directing therapeutic procedures. We review the mechanisms of action of first, second and third generation contrast...... agents and their use in various endoscopic procedures in the gastrointestinal tract. Various applications of contrast-enhanced endoscopic ultrasonography include differentiating benign from malignant mediastinal lymphadenopathy, assessment of depth of invasion of esophageal, gastric and gall bladder...... cancers and visualization of the portal venous system and esophageal varices. In addition, contrast agents can be used to differentiate pancreatic lesions. The use of color Doppler further increases the ability to diagnose and differentiate various pancreatic malignancies. The sensitivity of power Doppler...

  5. Shale Oil Value Enhancement Research

    Energy Technology Data Exchange (ETDEWEB)

    James W. Bunger

    2006-11-30

    Raw kerogen oil is rich in heteroatom-containing compounds. Heteroatoms, N, S & O, are undesirable as components of a refinery feedstock, but are the basis for product value in agrochemicals, pharmaceuticals, surfactants, solvents, polymers, and a host of industrial materials. An economically viable, technologically feasible process scheme was developed in this research that promises to enhance the economics of oil shale development, both in the US and elsewhere in the world, in particular Estonia. Products will compete in existing markets for products now manufactured by costly synthesis routes. A premium petroleum refinery feedstock is also produced. The technology is now ready for pilot plant engineering studies and is likely to play an important role in developing a US oil shale industry.

  6. Enhanced NIF neutron activation diagnostics.

    Science.gov (United States)

    Yeamans, C B; Bleuel, D L; Bernstein, L A

    2012-10-01

    The NIF neutron activation diagnostic suite relies on removable activation samples, leading to operational inefficiencies and a fundamental lower limit on the half-life of the activated product that can be observed. A neutron diagnostic system measuring activation of permanently installed samples could remove these limitations and significantly enhance overall neutron diagnostic capabilities. The physics and engineering aspects of two proposed systems are considered: one measuring the (89)Zr/(89 m)Zr isomer ratio in the existing Zr activation medium and the other using potassium zirconate as the activation medium. Both proposed systems could improve the signal-to-noise ratio of the current system by at least a factor of 5 and would allow independent measurement of fusion core velocity and fuel areal density.

  7. Enhanced Li-Ion Battery

    Directory of Open Access Journals (Sweden)

    Natasha Ross

    2015-01-01

    Full Text Available Au with Pd nanoparticles were synthesized and coated onto the spinel LiMn2O4 via a coprecipitation calcination method with the objective to improve the microstructure, conductivity, and electrochemical activities of pristine LiMn2O4. The novel LiPdAuxMn2-xO4 composite cathode had high phase purity, well crystallized particles, and more regular morphological structures with narrow size distributions. At enlarged cycling potential ranges the LiPdAuxMn2-xO4 sample delivered 90 mAh g−1 discharge capacity compared to LiMn2O4 (45 mAh g−1. It was concluded that even a small amount of the Pd and Au enhanced both the lithium diffusivity and electrochemical conductivity of the host sample due to the beneficial properties of their synergy.

  8. Maintainability effectiveness evaluations and enhancement

    International Nuclear Information System (INIS)

    Seminara, J.L.

    1985-01-01

    In the mid-seventies EPRI initiated a research project to review the human factors aspects of nuclear power plant control rooms. In the course of investigating operator-control room interfaces in five operational control rooms, it became evident that many plant outages had either been caused or prolonged by human factors problems associated with maintenance activities. Consequently, as one of several follow-on projects, EPRI sponsored a review of nine power plants (five nuclear and four fossil) to examine the human factors aspects of plant maintainability. This survey revealed a wide variety of generic human factors problems that could negatively impact the effectiveness of plant maintenance personnel. It was clear that plant maintainability features deserved no less attention to human factors concerns than the operational features of the control room. This paper describes subsequent EPRI-initiated efforts to assist the utilities in conducting self-reviews of maintainability effectiveness and effect needed enhancements

  9. Magnetically enhanced vacuum arc thruster

    International Nuclear Information System (INIS)

    Keidar, Michael; Schein, Jochen; Wilson, Kristi; Gerhan, Andrew; Au, Michael; Tang, Benjamin; Idzkowski, Luke; Krishnan, Mahadevan; Beilis, Isak I

    2005-01-01

    A hydrodynamic model of the vacuum arc thruster and its plume is described. Primarily an effect of the magnetic field on the plume expansion and plasma generation is considered. Two particular examples are investigated, namely the magnetically enhanced co-axial vacuum arc thruster (MVAT) and the vacuum arc thruster with ring electrodes (RVAT). It is found that the magnetic field significantly decreases the plasma plume radial expansion under typical conditions. Predicted plasma density profiles in the plume of the MVAT are compared with experimental profiles, and generally a good agreement is found. In the case of the RVAT the influence of the magnetic field leads to plasma jet deceleration, which explains the non-monotonic dependence of the ion current density, on an axial magnetic field observed experimentally

  10. Magnetically enhanced vacuum arc thruster

    Energy Technology Data Exchange (ETDEWEB)

    Keidar, Michael [University of Michigan, Ann Arbor 48109 MI (United States); Schein, Jochen [Alameda Applied Science Corporation, San Leandro, CA 94577 (United States); Wilson, Kristi [Alameda Applied Science Corporation, San Leandro, CA 94577 (United States); Gerhan, Andrew [Alameda Applied Science Corporation, San Leandro, CA 94577 (United States); Au, Michael [Alameda Applied Science Corporation, San Leandro, CA 94577 (United States); Tang, Benjamin [Alameda Applied Science Corporation, San Leandro, CA 94577 (United States); Idzkowski, Luke [Alameda Applied Science Corporation, San Leandro, CA 94577 (United States); Krishnan, Mahadevan [Alameda Applied Science Corporation, San Leandro, CA 94577 (United States); Beilis, Isak I [Tel Aviv University, Tel Aviv (Israel)

    2005-11-01

    A hydrodynamic model of the vacuum arc thruster and its plume is described. Primarily an effect of the magnetic field on the plume expansion and plasma generation is considered. Two particular examples are investigated, namely the magnetically enhanced co-axial vacuum arc thruster (MVAT) and the vacuum arc thruster with ring electrodes (RVAT). It is found that the magnetic field significantly decreases the plasma plume radial expansion under typical conditions. Predicted plasma density profiles in the plume of the MVAT are compared with experimental profiles, and generally a good agreement is found. In the case of the RVAT the influence of the magnetic field leads to plasma jet deceleration, which explains the non-monotonic dependence of the ion current density, on an axial magnetic field observed experimentally.

  11. Picobubble enhanced fine coal flotation

    Energy Technology Data Exchange (ETDEWEB)

    Tao, Y.J.; Liu, J.T.; Yu, S.; Tao, D. [University of Kentucky, Lexington, KY (United States). Dept. of Mining Engineering

    2006-07-01

    Froth flotation is widely used in the coal industry to clean -28 mesh fine coal. A successful recovery of particles by flotation depends on efficient particle-bubble collision and attachment with minimal subsequent particle detachment from bubble. Flotation is effective in a narrow size range beyond which the flotation efficiency drops drastically. It is now known that the low flotation recovery of particles in the finest size fractions is mainly due to a low probability of bubble-particle collision while the main reason for poor coarse particle flotation recovery is the high probability of detachment. A fundamental analysis has shown that use of picobubbles can significantly improve the flotation recovery of particles in a wide range of size by increasing the probability of collision and attachment and reducing the probability of detachment. A specially designed column with a picobubble generator has been developed for enhanced recovery of fine coal particles. Picobubbles were produced based on the hydrodynamic cavitation principle. They are characterized by a size distribution that is mostly below 1 {mu}m and adhere preferentially to the hydrophobic surfaces. The presence of picobubbles increases the probability of collision and attachment and decreases the probability of detachment, thus enhancing flotation recovery. Experimental results with the Coalberg seam coal in West Virginia, U.S.A. have shown that the use of picobubbles in a 2 in. column flotation increased fine coal recovery by 10-30%, depending on the feed rate, collector dosage, and other flotation conditions. Picobubbles also acted as a secondary collector and reduced the collector dosage by one third to one half.

  12. CIRCLE Enhancement After Myopic SMILE.

    Science.gov (United States)

    Siedlecki, Jakob; Luft, Nikolaus; Mayer, Wolfgang J; Siedlecki, Martin; Kook, Daniel; Meyer, Bertram; Bechmann, Martin; Wiltfang, Rainer; Priglinger, Siegfried G; Dirisamer, Martin

    2018-05-01

    To report the outcomes of enhancement after small incision lenticule extraction (SMILE) using the VisuMax CIRCLE option (Carl Zeiss Meditec AG, Jena, Germany), which converts the SMILE cap into a femtosecond LASIK flap for secondary excimer laser application. Of 2,065 SMILE procedures, 22 eyes (1.1%) re-treated with CIRCLE with a follow-up of 3 months were included in the analysis. SMILE was performed in the usual manner. For re-treatment, the CIRCLE procedure was performed with pattern D flap creation on the VisuMax system and subsequent excimer laser ablation with a Zeiss MEL 90 laser (Carl Zeiss Meditec) with plano target in all cases. Spherical equivalent was -5.56 ± 2.22 diopters (D) before SMILE and -0.51 ± 1.08 D before CIRCLE. CIRCLE enhancement was performed after a mean of 10.0 ± 7.9 months, allowed for safe flap lifting in all eyes, and resulted in a final manifest refraction spherical equivalent of 0.18 ± 0.31 D at 3 months (P line of UDVA. Corrected distance visual acuity (CDVA) remained unchanged at all time points (before vs after CIRCLE, P = .40). Two eyes (9.1 %) lost one line of CDVA; no eye lost two or more lines. The safety and efficacy indices were 1.03 and 0.97 at 3 months. The CIRCLE procedure represents an effective re-treatment option after SMILE. Compared to surface ablation re-treatment after SMILE, CIRCLE seems to offer advantages in respect to speed of visual recovery, safety, and predictability, but at the price of flap creation. [J Refract Surg. 2018;34(5):304-309.]. Copyright 2018, SLACK Incorporated.

  13. Delayed enhanced MRI in intraparenchymal tumors

    International Nuclear Information System (INIS)

    Eguchi, Takahiko; Morimoto, Tetsuya; Takeshima, Toshikazu

    1991-01-01

    Delayed enhanced MRI was performed on 20 intraparenchymal tumors, and these findings were compared with those of early enhanced MRI. Using the spin-echo technique (SE: 400-500/20 msec), early scans were obtained 5 minutes, and delayed scans were obtained 60 minutes, after the intravenous injection of 0.1 nmol of gadolinium-DTPA/Kg. We discussed the changes in the delayed scan with regard to the change in the pattern of enhancement and the boundary of enhancement. In these twenty intraparenchymal tumors, there were three low-grade astrocytomas, two anaplastic astrocytomas, seven glioblastomas, and eight metastatic tumors. The changes in the enhanced pattern showed three types as follows: Type I: heterogeneous enhancement in both early and delayed scans; Type II: heterogeneous enhancement in early scan and homogeneous enhancement in delayed scan; Type III: homogeneous enhancement in both early and delayed scans. Most malignant tumors, such as glioblastomas (6/8), anaplastic astrocytomas (2/2), and metastatic tumors (7/8), revealed Type I, although low-grade astrocytomas showed Type II (3/2) and Type III (1/3). The heterogeneous enhancement in delayed scan was found in malignant tumors and in low-grade astrocytoma; even if the early scan revealed heterogeneous enhancement, the delayed scan showed homogeneous enhancement. In the delayed scan, most enhanced boundaries spread out of the boundaries in the early scan. Glioblastomas spread markedly in the delayed scan, although none of the low-grade astrocytomas, anaplastic astrocytomas, or metastases revealed marked spreading. We called these marked increases in the delayed scan a 'spreading sign' and thought that this sign was specific to glioblastomas. Recently some authors have emphasized the usefulness of serial scans. Delayed enhanced MRI 60 minutes after the administration of a contrast medium was here found also to be useful for the accurate diagnosis for brain tumors. (author)

  14. Enhanced MRI in patients with facial palsy

    International Nuclear Information System (INIS)

    Yanagida, Masahiro; Kato, Tsutomu; Ushiro, Koichi; Kitajiri, Masanori; Yamashita, Toshio; Kumazawa, Tadami; Tanaka, Yoshimasa

    1991-01-01

    We performed Gd-DTPA-enhanced magnetic resonance imaging (MRI) examinations at several stages in 40 patients with peripheral facial nerve palsy (Bell's palsy and Ramsay-Hunt syndrome). In 38 of the 40 patients, one and more enhanced region could be seen in certain portion of the facial nerve in the temporal bone on the affected side, whereas no enhanced regions were seen on the intact side. Correlations between the timing of the MRI examination and the location of the enhanced regions were analysed. In all 6 patients examined by MRI within 5 days after the onset of facial nerve palsy, enhanced regions were present in the meatal portion. In 3 of the 8 patients (38%) examined by MRI 6 to 10 days after the onset of facial palsy, enhanced areas were seen in both the meatal and labyrinthine portions. In 8 of the 9 patients (89%) tested 11 to 20 days after the onset of palsy, the vertical portion was enhanced. In the 12 patients examined by MRI 21 to 40 days after the onset of facial nerve palsy, the meatal portion was not enhanced while the labyrinthine portion, the horizontal portion and the vertical portion were enhanced in 5 (42%), 8 (67%) and 11 (92%), respectively. Enhancement in the vertical portion was observed in all 5 patients examined more than 41 days after the onset of facial palsy. These results suggest that the central portion of the facial nerve in the temporal bone tends to be enhanced in the early stage of facial nerve palsy, while the peripheral portion is enhanced in the late stage. These changes of Gd-DTPA enhanced regions in the facial nerve may suggest dromic degeneration of the facial nerve in peripheral facial nerve palsy. (author)

  15. Detectability of hepatocellular carcinoma: comparison of Gd-DTPA-enhanced and SPIO-enhanced MR imaging

    International Nuclear Information System (INIS)

    Kwak, Hyo Sung; Lee, Jeong Min; Kim In Hwan; Kim, Chong Soo; Han, Hyeun Young; Yoon, Kwon ha; Shin, Kyung Sook

    2000-01-01

    To compare the detectability of hepatocellular carcinoma (HCC) using superparamagnetic iron oxide (SPIO)-enhanced T2-weighted turbo spin echo (TSE), SPIO-enhanced T2-weighted FISP, and dynamic Gd-DTPA-enhanced fast low-angle shot (FLASH) MR images. In order to assess their hepatic lesions, 25 patients (20 men and 5 women) with HCC were enrolled in an MR study in which both gadolinium and Spiro were used. Since the lesions were most conspicuous during the phase of dynamic arterial dominant phase of dynamic gadolinium-enhanced imaging, this was the phase used for analysis. Images were analyzed qualitatively and quantitatively, and to compare the diagnostic value of gadolinium-enhanced imaging with that of SPIO-enhanced imaging for the detection of HCCs, a receiver-operated characteristic curve was obtained. Qualitative analysis revealed a significantly higher percentage of signal loss and a higher liver-lesion contrast-to-noise ratio on SPIO-enhanced FISP imaging than on SPIO-enhanced T2-weighted TSE imaging (p less than 0.05). It also showed that the lesions were most clearly visible on SPIO-enhanced FISP imaging (and significantly so), followed by SPIO-enhanced T2-weighted TSE imaging, and dynamic gadolinium-enhanced imaging. Imaging artifacts were more prominent on SPIO-enhanced T2-weighted TSE than on SPIO-enhanced PISF imaging or dynamic gadolinium-enhanced imaging (p less than 0.05). According to ROC analysis, SPIO-enhanced T2-weighted turbo spin echo (TSE) or SPIO-enhanced FISP imaging achieved higher accuracy than did dynamic gadolinium-enhanced FLASH imaging (p less than 0.05). For the detection of hepatocellular carcinomas, SPIO-enhanced MR imaging is better than gadolinium-enhanced FLASH imaging

  16. Does technology really enhance nurse education?

    Science.gov (United States)

    Goodchild, Tim

    2018-07-01

    Technology has clearly impacted upon our working lives, and the purpose of this paper is to offer a critical insight into the ubiquitous presence of technology in nurse education. This paper argues that technology enhanced learning is predicated on the promise of potential and purported transformation of teaching and learning. It suggests that there is a lack of critical engagement in the academic field of technology enhanced learning, and adds a critical voice to some of the emerging arguments in this area. There is also a lack of systematic evidence supporting the enhancement offered by technology, and yet the technology enhanced project continues to persist. The discourse surrounding technology enhanced learning has become so dominant, so pervasive, that those of us within it can no longer see alternatives. But there are alternatives, and this paper argues that we need to challenge the dominance of technology enhanced learning, and become aware of its contingent nature. Copyright © 2018 Elsevier Ltd. All rights reserved.

  17. Comparative enhancing effects of electret with chemical enhancers on transdermal delivery of meloxicam in vitro

    International Nuclear Information System (INIS)

    Cui, L L; Hou, X M; Li, G D; Jiang, J; Liang, Y Y; Xin, X

    2008-01-01

    Electret offers enhancing effect in transdermal drug delivery for altering of the arrangement of lipid molecules in the stratum corneum, forming many transient permeable apertures and enhancing the transdermal drug delivery. In this paper, meloxicam patch formulations were developed to make the comparative study of transdermal drug delivery between electret and chemical enhancers. Patches were made into control, electret, chemical enhancer and electret with chemical enhancer ones, according to the preparation procedure. The electret combined with chemical enhancer patch was designed to probe the incorporation between electret and chemical enhancer in transdermal drug delivery. The meloxicam release from the patch was found to increase in order of blank, chemical enhancer, electret and electret with chemical enhancer patch, in general.

  18. Gd-enhanced MR imaging of the herniated lumbar disc: patterns of enhancement

    International Nuclear Information System (INIS)

    Kwag, Hyon Joo; Choi, Hye Young; Kim, Hyae Young; Kim, Yoo Kyung; Kim, Ah Young; Chung, Eun Chul

    1995-01-01

    The purpose of this study is to describe the patterns of enhancement of the herniated lumbar disc with Gd-DTPA enhanced MR imaging. Out of 65 patients, 103 lumbar discs diagnosed to be herniated by MR image were retrospectively analyzed. The MR imaging was performed with 1.5 T MR unit, using T1-and T2-weighted sagittal and axial spin echo techniques. Contrast-enhanced T1 weighted sagittal and axial images were performed after intravenous injection of Gadopentetate-dimeglumine(Magnevist, Shering) (0.1 mmol/kg). Contrast enhancement was seen in 66 cases(64%). Thirteen cases of bulging disc were not enhanced. Twenty-eight cases of protruded disc showed intraannular enchantment in 23 cases, peripheral linear and irregular enhancement in each of one case, and nonenhancement in three cases. Fifty-seven cases of extruded disc showed irregular enhancement in 14 cases, peripheral linear enhancement in 12 cases, peripheral ring enhancement in five cases and intraannular enhancement in five cases. All five cases of sequestered disc showed peripheral ring enhancement. Protruded discs show intraannular enhancement frequently and sequestered discs usually show peripheral ring enhancement. Enhanced MR imaging may be helpful to evaluate the type of herniated lumbar disc and relationship among disc material, nerve root and thecal sac

  19. Enhancement patterns and pseudo-washout of hepatic haemangiomas on gadoxetate disodium-enhanced liver MRI

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Bohyun [University of Ulsan College of Medicine, Asan Medical Center, Department of Radiology and Research Institute of Radiology, Seoul (Korea, Republic of); Ajou University School of Medicine, Department of Radiology, Suwon (Korea, Republic of); Byun, Jae Ho; Kim, Hyoung Jung; Won, Hyung Jin; Kim, So Yeon; Shin, Yong Moon; Kim, Pyo Nyun [University of Ulsan College of Medicine, Asan Medical Center, Department of Radiology and Research Institute of Radiology, Seoul (Korea, Republic of)

    2016-01-15

    To compare the enhancement patterns and prevalence of pseudo-washout between rapidly and slowly enhancing hepatic haemangiomas on gadoxetate disodium-enhanced MRI in patients with chronic liver disease (CLD) and healthy liver (HL). On gadoxetate disodium-enhanced MRI, the extent of intralesional arterial enhancement >50 % and ≤50 % of lesions was defined as rapid and slow enhancement, respectively. The enhancement patterns and presence of pseudo-washout during the portal venous phase (PVP) and transitional phase (TP) of 74 hepatic haemangiomas were retrospectively evaluated in the CLD and HL groups. Sequential changes of signal-to-noise ratio (SNR) were measured in unenhanced phase, PVP and TP. Irrespective of hepatic health status, pseudo-washout in TP was significantly more common in the rapidly enhancing haemangiomas (p ≤ 0.026). In both groups, rapidly enhancing haemangiomas showed complete or progressive incomplete enhancement in PVP, which either lasted or transformed to pseudo-washout in TP, whereas slowly enhancing haemangiomas showed progressive incomplete enhancement in PVP and TP. SNR of hepatic parenchyma continued to rise until TP, whereas that of portal vein and haemangioma falls in TP. Regardless of CLD, pseudo-washout in TP was more common in rapidly than in slowly enhancing haemangiomas, with enhancement patterns differing in the two subgroups. (orig.)

  20. Enhancement patterns and pseudo-washout of hepatic haemangiomas on gadoxetate disodium-enhanced liver MRI

    International Nuclear Information System (INIS)

    Kim, Bohyun; Byun, Jae Ho; Kim, Hyoung Jung; Won, Hyung Jin; Kim, So Yeon; Shin, Yong Moon; Kim, Pyo Nyun

    2016-01-01

    To compare the enhancement patterns and prevalence of pseudo-washout between rapidly and slowly enhancing hepatic haemangiomas on gadoxetate disodium-enhanced MRI in patients with chronic liver disease (CLD) and healthy liver (HL). On gadoxetate disodium-enhanced MRI, the extent of intralesional arterial enhancement >50 % and ≤50 % of lesions was defined as rapid and slow enhancement, respectively. The enhancement patterns and presence of pseudo-washout during the portal venous phase (PVP) and transitional phase (TP) of 74 hepatic haemangiomas were retrospectively evaluated in the CLD and HL groups. Sequential changes of signal-to-noise ratio (SNR) were measured in unenhanced phase, PVP and TP. Irrespective of hepatic health status, pseudo-washout in TP was significantly more common in the rapidly enhancing haemangiomas (p ≤ 0.026). In both groups, rapidly enhancing haemangiomas showed complete or progressive incomplete enhancement in PVP, which either lasted or transformed to pseudo-washout in TP, whereas slowly enhancing haemangiomas showed progressive incomplete enhancement in PVP and TP. SNR of hepatic parenchyma continued to rise until TP, whereas that of portal vein and haemangioma falls in TP. Regardless of CLD, pseudo-washout in TP was more common in rapidly than in slowly enhancing haemangiomas, with enhancement patterns differing in the two subgroups. (orig.)

  1. Enhancing professionalism at GPU nuclear

    International Nuclear Information System (INIS)

    Coe, R.P.; Landy, F.J.

    1991-01-01

    Late in 1988, GPU Nuclear embarked on a major program aimed at enhancing Professionalism at its Oyster Creek and Three Mile Island Nuclear Generating Stations. The program was also to include its Corporate Headquarters in Parsippany, New Jersey. The overall program was to take several directions which included on-site degree programs, a sabbatical leave-type program for personnel to finish college degrees, advanced technical training for licensed staff, career progression for SROs and expanded teamwork and leadership training for control room crews. The largest portion of this initiative was the development and delivery of professionalism training to the nearly two thousand people at both sites. Three primary philosophies guided the development of the program. Employees as Experts: First, GPU Nuclear employees were considered to be the most valuable source of information for designing a Professionalism program because it is these individuals who are sensitive to the issues encountered in the workplace. Realism: The second philosophy guiding this effort was that the program must be grounded in real life challenges that employees face and must address. Active Learning: The third guiding philosophy was that, in order to have any real impact on the way employees think about professionalism, the program must utilize active rather than passive learning techniques

  2. Biopolymeric nanocomposites with enhanced interphases.

    Science.gov (United States)

    Yin, Yi; Hu, Kesong; Grant, Anise M; Zhang, Yuhong; Tsukruk, Vladimir V

    2015-10-06

    Ultrathin and robust nanocomposite membranes were fabricated by incorporating graphene oxide (GO) sheets into a silk fibroin (SF) matrix by a dynamic spin-assisted layer-by-layer assembly (dSA-LbL). We observed that in contrast to traditional SA-LbL reported earlier fast solution removal during dropping of solution on constantly spinning substrates resulted in largely unfolded biomacromolecules with enhanced surface interactions and suppressed nanofibril formation. The resulting laminated nanocomposites possess outstanding mechanical properties, significantly exceeding those previously reported for conventional LbL films with similar composition. The tensile modulus reached extremely high values of 170 GPa, which have never been reported for graphene oxide-based nanocomposites, the ultimate strength was close to 300 MPa, and the toughness was above 3.4 MJ m(-3). The failure modes observed for these membranes suggested the self-reinforcing mechanism of adjacent graphene oxide sheets with strong 2 nm thick silk interphase composed mostly from individual backbones. This interphase reinforcement leads to the effective load transfer between the graphene oxide components in reinforced laminated nanocomposite materials with excellent mechanical strength that surpasses those known today for conventional flexible laminated carbon nanocomposites from graphene oxide and biopolymer components.

  3. Carbon-enhanced VRLA batteries.

    Energy Technology Data Exchange (ETDEWEB)

    Enos, David George; Hund, Thomas D.; Shane, Rod (East Penn Manufacturing, Lyon Station, PA)

    2010-10-01

    The addition of certain forms of carbon to the negative plate in valve regulated lead acid (VRLA) batteries has been demonstrated to increase the cycle life of such batteries by an order of magnitude or more under high-rate, partial-state-of-charge operation. Such performance will provide a significant impact, and in some cases it will be an enabling feature for applications including hybrid electric vehicles, utility ancillary regulation services, wind farm energy smoothing, and solar photovoltaic energy smoothing. There is a critical need to understnd how the carbon interacts with the negative plate and achieves the aforementioned benefits at a fundamental level. Such an understanding will not only enable the performance of such batteries to be optimzied, but also to explore the feasibility of applying this technology to other battery chemistries. In partnership with the East Penn Manufacturing, Sandia will investigate the electrochemical function of the carbon and possibly identify improvements to its anti-sulfation properties. Shiomi, et al. (1997) discovered that the addition of carbon to the negative active material (NAM) substantially reduced PbSO{sub 4} accumulation in high rate, partial state of charge (HRPSoC) cycling applications. This improved performance with a minimal cost. Cycling applications that were uneconomical for traditional VRLA batteries are viable for the carbon enhanced VRLA. The overall goal of this work is to quantitatively define the role that carbon plays in the electrochemistry of a VRLA battery.

  4. Enhanced safeguards via solution monitoring

    International Nuclear Information System (INIS)

    Burr, T.; Wangen, L.

    1996-09-01

    Solution monitoring is defined as the essentially continuous monitoring of solution level, density, and temperature in all tanks in the process that contain, or could contain, safeguards-significant quantities of nuclear material. This report describes some of the enhancements that solution monitoring could make to international safeguards. The focus is on the quantifiable benefits of solution monitoring, but qualitatively, solution monitoring can be viewed as a form of surveillance. Quantitatively, solution monitoring can in some cases improve diversion detection probability. For example, the authors show that under certain assumptions, solution monitoring can be used to reduce the standard deviation of the annual material balance, σ MB , from approximately 17 kg to approximately 4 kg. Such reduction in σ MB will not always be possible, as they discuss. However, in all cases, solution monitoring would provide assurance that the measurement error models are adequate so that one has confidence in his estimate of σ MB . Some of the results in this report were generated using data that were simulated with prototype solution monitoring software that they are developing. An accompanying document describes that software

  5. Superhydrophobicity enhancement through substrate flexibility

    Science.gov (United States)

    Vasileiou, Thomas; Gerber, Julia; Prautzsch, Jana; Schutzius, Thomas; Poulikakos, Dimos

    2017-11-01

    Inspired by manifestations in nature, micro/nanoengineering superhydrophobic surfaces has been the focus of much work. Generally, hydrophobicity is increased through the combined effects of surface texturing and chemistry; being durable, rigid substrate materials are the norm. However, many natural and technical materials are flexible, and the resulting effect on hydrophobicity has been largely unexplored. Here, we show that the rational tuning of flexibility can work collaboratively with the surface micro/nanotexture to enhance liquid repellency performance, defined by impalement and breakup resistance, contact time reduction, and restitution coefficient increase. Reduction in substrate stiffness and areal density imparts immediate acceleration and intrinsic responsiveness to impacting droplets, mitigating the collision and lowering the impalement probability by 60 % without the need for active actuation. We demonstrate the above discoveries with materials ranging from thin steel or polymer sheets to butterfly wings. Partial support of the Swiss National Science Foundation under Grant 162565 and the European Research Council under Advanced Grant 669908 (INTICE) is acknowledged.

  6. Does facial resemblance enhance cooperation?

    Directory of Open Access Journals (Sweden)

    Trang Giang

    Full Text Available Facial self-resemblance has been proposed to serve as a kinship cue that facilitates cooperation between kin. In the present study, facial resemblance was manipulated by morphing stimulus faces with the participants' own faces or control faces (resulting in self-resemblant or other-resemblant composite faces. A norming study showed that the perceived degree of kinship was higher for the participants and the self-resemblant composite faces than for actual first-degree relatives. Effects of facial self-resemblance on trust and cooperation were tested in a paradigm that has proven to be sensitive to facial trustworthiness, facial likability, and facial expression. First, participants played a cooperation game in which the composite faces were shown. Then, likability ratings were assessed. In a source memory test, participants were required to identify old and new faces, and were asked to remember whether the faces belonged to cooperators or cheaters in the cooperation game. Old-new recognition was enhanced for self-resemblant faces in comparison to other-resemblant faces. However, facial self-resemblance had no effects on the degree of cooperation in the cooperation game, on the emotional evaluation of the faces as reflected in the likability judgments, and on the expectation that a face belonged to a cooperator rather than to a cheater. Therefore, the present results are clearly inconsistent with the assumption of an evolved kin recognition module built into the human face recognition system.

  7. An enhanced tokamak startup model

    Science.gov (United States)

    Goswami, Rajiv; Artaud, Jean-François

    2017-01-01

    The startup of tokamaks has been examined in the past in varying degree of detail. This phase typically involves the burnthrough of impurities and the subsequent rampup of plasma current. A zero-dimensional (0D) model is most widely used where the time evolution of volume averaged quantities determines the detailed balance between the input and loss of particle and power. But, being a 0D setup, these studies do not take into consideration the co-evolution of plasma size and shape, and instead assume an unchanging minor and major radius. However, it is known that the plasma position and its minor radius can change appreciably as the plasma evolves in time to fill in the entire available volume. In this paper, an enhanced model for the tokamak startup is introduced, which for the first time takes into account the evolution of plasma geometry during this brief but highly dynamic period by including realistic one-dimensional (1D) effects within the broad 0D framework. In addition the effect of runaway electrons (REs) has also been incorporated. The paper demonstrates that the inclusion of plasma cross section evolution in conjunction with REs plays an important role in the formation and development of tokamak startup. The model is benchmarked against experimental results from ADITYA tokamak.

  8. Enhanced Recovery after Vascular Surgery

    Directory of Open Access Journals (Sweden)

    Milena D. Stojanovic

    2018-01-01

    Full Text Available The beginnings of the enhanced recovery after surgery (ERAS program were first developed for patients in colorectal surgery, and after it was established as the standard of care in this surgical field, it began to be applied in many others surgical areas. This is multimodal, evidence-based approach program and includes simultaneous optimization of preoperative status of patients, adequate selection of surgical procedure and postoperative management. The aim of this program is to reduce complications, the length of hospital stay and to improve the patients outcome. Over the past decades, special attention was directed to the postoperative management in vascular surgery, especially after major vascular surgery because of the great risk of multiorgan failure, such as: respiratory failure, myocardial infarction, hemodynamic instability, coagulopathy, renal failure, neurological disorders, and intra-abdominal complications. Although a lot of effort was put into it, there is no unique acceptable program for ERAS in this surgical field, and there is still a need to point out the factors responsible for postoperative outcomes of these patients. So far, it is known that special attention should be paid to already existing diseases, type and the duration of the surgical intervention, hemodynamic and fluid management, nutrition, pain management, and early mobilization of patients.

  9. Enhanced Model for Fast Ignition

    Energy Technology Data Exchange (ETDEWEB)

    Mason, Rodney J. [Research Applications Corporation, Los Alamos, NM (United States)

    2010-10-12

    Laser Fusion is a prime candidate for alternate energy production, capable of serving a major portion of the nation's energy needs, once fusion fuel can be readily ignited. Fast Ignition may well speed achievement of this goal, by reducing net demands on laser pulse energy and timing precision. However, Fast Ignition has presented a major challenge to modeling. This project has enhanced the computer code ePLAS for the simulation of the many specialized phenomena, which arise with Fast Ignition. The improved code has helped researchers to understand better the consequences of laser absorption, energy transport, and laser target hydrodynamics. ePLAS uses efficient implicit methods to acquire solutions for the electromagnetic fields that govern the accelerations of electrons and ions in targets. In many cases, the code implements fluid modeling for these components. These combined features, "implicitness and fluid modeling," can greatly facilitate calculations, permitting the rapid scoping and evaluation of experiments. ePLAS can be used on PCs, Macs and Linux machines, providing researchers and students with rapid results. This project has improved the treatment of electromagnetics, hydrodynamics, and atomic physics in the code. It has simplified output graphics, and provided new input that avoids the need for source code access by users. The improved code can now aid university, business and national laboratory users in pursuit of an early path to success with Fast Ignition.

  10. Enhanced wall pumping in JET

    International Nuclear Information System (INIS)

    Ehrenberg, J.; Harbour, P.J.

    1991-01-01

    The enhanced wall pumping phenomenon in JET is observed for hydrogen or deuterium plasmas which are moved from the outer (larger major radius) limiter position either to the inner wall or to the top/bottom wall of the vacuum vessel. This phenomenon is analysed by employing a particle recycling model which combines plasma particle transport with particle re-emission from and retention within material surfaces. The model calculates the important experimentally observable quantities, such as particle fluxes, global particle confinement time, plasma density and density profile. Good qualitative agreement is found and, within the uncertainties, the agreement is quantitative if the wall pumping is assumed to be caused by two simultaneously occurring effects: (1) Neutral particle screening at the inner wall and the top/bottom wall is larger than that at the outer limiter because of different magnetic topologies at different poloidal positions; and (2) although most of the particles (≥ 90%) impacting on the wall can be promptly re-emitted, a small fraction (≤ 10%) of them must be retained in the wall for a period of time which is similar to or larger than the global plasma particle confinement time. However, the wall particle retention time need not be different from that of the outer limiter, i.e. pumping can occur when there is no difference between the material properties of the limiter and those of the wall. (author). 45 refs, 18 figs

  11. Labor potential: enhancing its development

    Directory of Open Access Journals (Sweden)

    O.P. Melnichuk

    2016-06-01

    Full Text Available This publication presents the views of the author about the need to expand research of labor potential, estimation of quantitative indicators and qualitative characteristics at the individual, regional levels and the state as a whole to develop the mechanisms of its development. The existing methods of labour potential assessment are mainly based on the probable approach taking into account external and internal factors. In the case of assessment of labour potential of a single enterprise for the most suitable for this production method the mechanisms of its development can be worked out. However, for the state under a certain depreciation of the resource, property, financial and other potentials, aggressive manifestations of the crisis phenomena, processes etc. to resolve urgent is the problem of enhancing the development of qualitative characteristics of labor potential at all its levels. In this context it is important to exploit the potential of domestic education and science which now continue to be reformed for the sake of achieving European standards, using the advanced experience of other countries. Every means of legal, financial, managerial, and organizational impact should be used for this.

  12. Coherently Enhanced Wireless Power Transfer

    Science.gov (United States)

    Krasnok, Alex; Baranov, Denis G.; Generalov, Andrey; Li, Sergey; Alù, Andrea

    2018-04-01

    Extraction of electromagnetic energy by an antenna from impinging external radiation is at the basis of wireless communications and wireless power transfer (WPT). The maximum of transferred energy is ensured when the antenna is conjugately matched, i.e., when it is resonant and it has an equal coupling with free space and its load. This condition, however, can be easily affected by changes in the environment, preventing optimal operation of a WPT system. Here, we introduce the concept of coherently enhanced WPT that allows us to bypass this difficulty and achieve dynamic control of power transfer. The approach relies on coherent excitation of the waveguide connected to the antenna load with a backward propagating signal of specific amplitude and phase. This signal creates a suitable interference pattern at the load resulting in a modification of the local wave impedance, which in turn enables conjugate matching and a largely increased amount of extracted energy. We develop a simple theoretical model describing this concept, demonstrate it with full-wave numerical simulations for the canonical example of a dipole antenna, and verify experimentally in both near-field and far-field regimes.

  13. Carbon dioxide efficiency of terrestrial enhanced weathering

    OpenAIRE

    Moosdorf, Nils; Renforth, Philip; Hartmann, Jens

    2014-01-01

    Terrestrial enhanced weathering, the spreading of ultramafic silicate rock flour to enhance natural weathering rates, has been suggested as part of a strategy to reduce global atmospheric CO2 levels. We budget potential CO2 sequestration against associated CO2 emissions to assess the net CO2 removal of terrestrial enhanced weathering. We combine global spatial data sets of potential source rocks, transport networks, and application areas with associated CO2 emissions in optimistic and pessimi...

  14. Enhanced Gain in Photonic Crystal Amplifiers

    DEFF Research Database (Denmark)

    Ek, Sara; Semenova, Elizaveta; Hansen, Per Lunnemann

    2012-01-01

    We experimentally demonstrate enhanced gain in the slow-light regime of quantum well photonic crystal amplifiers. A strong gain enhancement is observed with the increase of the group refractive index, due to light slow-down. The slow light enhancement is shown in a amplified spontaneous emission....... These results are promising for short and efficient semiconductor optical amplifiers. This effect will also benefit other devices, such as mode locked lasers....

  15. Enhancement of colposcopic image by sulphosalicylic acid.

    Directory of Open Access Journals (Sweden)

    Khilnani P

    1993-01-01

    Full Text Available Acetic acid is used conventionally for enhancement of the colposcopic image. We used sulphosalicylic acid instead of acetic acid in 50 normal cases. The normal appearance was enhanced in all cases. The image was also enhanced in 70% cases of cervical intraepithelial neoplasia and 90% cases of cervical condyloma accuminata. The image was not inferior to that with acetic acid in any of the cases.

  16. Electroluminescence Efficiency Enhancement using Metal Nanoparticles

    National Research Council Canada - National Science Library

    Soref, Richard A; Khurgin, J. B; Sun, G

    2008-01-01

    We apply the "effective mode volume" theory to evaluate enhancement of the electroluminescence efficiency of semiconductor emitters placed in the vicinity of isolated metal nanoparticles and their arrays...

  17. Dural enhancement with primary calvarial lesions.

    Science.gov (United States)

    Arana, E; Martí-Bonmatí, L; Ricart, V; Pérez-Ebrí, M

    2004-11-01

    The purpose of this study was to relate the pathological and imaging features of dural enhancement and meningeal sign ("dural tail") on contrast-enhanced T1-weighted magnetic resonance (MR) images from patients with primary calvarial lesions as well to assess the accuracy of MR imaging in predicting dural invasion. Thirty-two calvarial tumors studied with contrast-enhanced MR imaging and histopathological examination of the dural specimens were reviewed. Sixteen patients presented dural enhancement, eight with tumor invasion. Tumoral invasion of the dura was observed in one case without enhancement. Malignant lesions showed enhanced dura more commonly than benign lesions (P=0.02). Nodular and discontinuous dural enhancement was statistically associated with dural invasion (P=0.05). Dural tail did not show a specific pathological association. Meningeal enhancement is a nonspecific reaction to calvarial lesions unless nodular and discontinuous. False-negative and -positive cases of dural invasion imply some limitation of contrast-enhanced MR imaging in predicting dural invasion by calvarial neoplasms.

  18. Dural enhancement with primary calvarial lesions

    Energy Technology Data Exchange (ETDEWEB)

    Arana, E. [Clinica Quiron, Department of Radiology, Valencia (Spain); Marti-Bonmati, L. [Clinica Quiron, Department of Radiology, Valencia (Spain); Hospital Universitario Dr. Peset, Department of Radiology, Valencia (Spain); Ricart, V. [Hospital de la Ribera, Department of Radiology, Valencia (Spain); Perez-Ebri, M. [Hospital Universitario Dr. Peset, Department of Pathology, Valencia (Spain)

    2004-11-01

    The purpose of this study was to relate the pathological and imaging features of dural enhancement and meningeal sign (''dural tail'') on contrast-enhanced T1-weighted magnetic resonance (MR) images from patients with primary calvarial lesions as well to assess the accuracy of MR imaging in predicting dural invasion. Thirty-two calvarial tumors studied with contrast-enhanced MR imaging and histopathological examination of the dural specimens were reviewed. Sixteen patients presented dural enhancement, eight with tumor invasion. Tumoral invasion of the dura was observed in one case without enhancement. Malignant lesions showed enhanced dura more commonly than benign lesions (P=0.02). Nodular and discontinuous dural enhancement was statistically associated with dural invasion (P=0.05). Dural tail did not show a specific pathological association. Meningeal enhancement is a nonspecific reaction to calvarial lesions unless nodular and discontinuous. False-negative and -positive cases of dural invasion imply some limitation of contrast-enhanced MR imaging in predicting dural invasion by calvarial neoplasms. (orig.)

  19. Patterns of uterine enhancement with helical CT

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, H.; Loyer, E.M.; Charnsangavej, C. [Department of Diagnostic Radiology, Box 57, The University of Texas, M.D. Anderson Cancer Center, 1515 Holcombe Blvd. Houston, TX 77030 (United States); Minami, M. [Department of Radiology, Faculty of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-Ku, Tokyo 113 (Japan)

    1998-10-01

    Objective: The purpose of this study was to evaluate the enhancement characteristics of the normal uterine body and cervix using dynamic contrast-enhanced helical CT. Methods: Thirty-eight women scheduled for pelvic CT for non-gynecologic malignancies underwent dynamic contrast-enhanced helical CT of the pelvis. Data acquisition was during the arterial phase (30-45 s after the start of injection), the parenchymal phase (90-120 s after the start of injection), and delayed phase (3-9 min after the start of injection). The images were evaluated by four radiologists for the pattern of myometrial and cervical enhancement. Correlation was made with the age and menstrual status of the patients. Results: In the uterine body, three types of enhancement were observed. Type 1 enhancement, seen in 16 patients (42%), was characterized by the visualization of a subendometrial zone of enhancement, 30-120 s after the start of injection. Eight of these patients also showed an enhancing zone in the outer myometrium. Both zones were transitory, and in all cases, the uterus became homogeneous in the delayed phase. This pattern was seen predominantly in premenopausal women with a mean age of 34 years. Type 2 enhancement, seen in 17 cases (45%), was defined by the absence of subendometrial enhancement in the early phase. Enhancement was either diffuse from the outset or originated in the outer myometrium. This pattern was seen nearly equally in premenopausal and postmenopausal women with a mean age of 40 years. Type 3 enhancement was seen in five postmenopausal patients (13%) with a mean age of 53 years and was characterized by faint diffuse enhancement. In the cervix, a zonal pattern of enhancement defining inner and outer stroma was seen in 23 patients (61%). Fifteen patients were premenopausal and eight were postmenopausal. Conclusion: In this study, we have shown a transitory zonal distribution of the contrast in the myometrium and cervix using dynamic contrast-enhanced helical CT

  20. Enhancing banana weevil ( Cosmopolites sordidus ) resistance by ...

    African Journals Online (AJOL)

    Enhancing banana weevil (Cosmopolites sordidus) resistance by plant genetic modification: A perspective. Andrew Kiggundu, Michael Pillay, Altus Viljoen, Clifford Gold, Wilberforce Tushemereirwe, Karl Kunert ...

  1. Patterns of uterine enhancement with helical CT

    International Nuclear Information System (INIS)

    Kaur, H.; Loyer, E.M.; Charnsangavej, C.; Minami, M.

    1998-01-01

    Objective: The purpose of this study was to evaluate the enhancement characteristics of the normal uterine body and cervix using dynamic contrast-enhanced helical CT. Methods: Thirty-eight women scheduled for pelvic CT for non-gynecologic malignancies underwent dynamic contrast-enhanced helical CT of the pelvis. Data acquisition was during the arterial phase (30-45 s after the start of injection), the parenchymal phase (90-120 s after the start of injection), and delayed phase (3-9 min after the start of injection). The images were evaluated by four radiologists for the pattern of myometrial and cervical enhancement. Correlation was made with the age and menstrual status of the patients. Results: In the uterine body, three types of enhancement were observed. Type 1 enhancement, seen in 16 patients (42%), was characterized by the visualization of a subendometrial zone of enhancement, 30-120 s after the start of injection. Eight of these patients also showed an enhancing zone in the outer myometrium. Both zones were transitory, and in all cases, the uterus became homogeneous in the delayed phase. This pattern was seen predominantly in premenopausal women with a mean age of 34 years. Type 2 enhancement, seen in 17 cases (45%), was defined by the absence of subendometrial enhancement in the early phase. Enhancement was either diffuse from the outset or originated in the outer myometrium. This pattern was seen nearly equally in premenopausal and postmenopausal women with a mean age of 40 years. Type 3 enhancement was seen in five postmenopausal patients (13%) with a mean age of 53 years and was characterized by faint diffuse enhancement. In the cervix, a zonal pattern of enhancement defining inner and outer stroma was seen in 23 patients (61%). Fifteen patients were premenopausal and eight were postmenopausal. Conclusion: In this study, we have shown a transitory zonal distribution of the contrast in the myometrium and cervix using dynamic contrast-enhanced helical CT

  2. Enhancing Ocean Research Data Access

    Science.gov (United States)

    Chandler, Cynthia; Groman, Robert; Shepherd, Adam; Allison, Molly; Arko, Robert; Chen, Yu; Fox, Peter; Glover, David; Hitzler, Pascal; Leadbetter, Adam; Narock, Thomas; West, Patrick; Wiebe, Peter

    2014-05-01

    The Biological and Chemical Oceanography Data Management Office (BCO-DMO) works in partnership with ocean science investigators to publish data from research projects funded by the Biological and Chemical Oceanography Sections and the Office of Polar Programs Antarctic Organisms & Ecosystems Program at the U.S. National Science Foundation. Since 2006, researchers have been contributing data to the BCO-DMO data system, and it has developed into a rich repository of data from ocean, coastal and Great Lakes research programs. While the ultimate goal of the BCO-DMO is to ensure preservation of NSF funded project data and to provide open access to those data, achievement of those goals is attained through a series of related phases that benefits from active collaboration and cooperation with a large community of research scientists as well as curators of data and information at complementary data repositories. The BCO-DMO is just one of many intermediate data management centers created to facilitate long-term preservation of data and improve access to ocean research data. Through partnerships with other data management professionals and active involvement in local and global initiatives, BCO-DMO staff members are working to enhance access to ocean research data available from the online BCO-DMO data system. Continuing efforts in use of controlled vocabulary terms, development of ontology design patterns and publication of content as Linked Open Data are contributing to improved discovery and availability of BCO-DMO curated data and increased interoperability of related content available from distributed repositories. We will demonstrate how Semantic Web technologies (e.g. RDF/XML, SKOS, OWL and SPARQL) have been integrated into BCO-DMO data access and delivery systems to better serve the ocean research community and to contribute to an expanding global knowledge network.

  3. Robotically enhanced rubber hand illusion.

    Science.gov (United States)

    Arata, Jumpei; Hattori, Masashi; Ichikawa, Shohei; Sakaguchi, Masamichi

    2014-01-01

    The rubber hand illusion is a well-known multisensory illusion. In brief, watching a rubber hand being stroked by a paintbrush while one's own unseen hand is synchronously stroked causes the rubber hand to be attributed to one's own body and to "feel like it's my hand." The rubber hand illusion is thought to be triggered by the synchronized tactile stimulation of both the subject's hand and the fake hand. To extend the conventional rubber hand illusion, we introduce robotic technology in the form of a master-slave telemanipulator. The developed one degree-of-freedom master-slave system consists of an exoskeleton master equipped with an optical encoder that is worn on the subject's index finger and a motor-actuated index finger on the rubber hand, which allows the subject to perform unilateral telemanipulation. The moving rubber hand illusion has been studied by several researchers in the past with mechanically connected rigs between the subject's body and the fake limb. The robotic instruments let us investigate the moving rubber hand illusion with less constraints, thus behaving closer to the classic rubber hand illusion. In addition, the temporal delay between the body and the fake limb can be precisely manipulated. The experimental results revealed that the robotic instruments significantly enhance the rubber hand illusion. The time delay is significantly correlated with the effect of the multisensory illusion, and the effect significantly decreased at time delays over 100 ms. These findings can potentially contribute to the investigations of neural mechanisms in the field of neuroscience and of master-slave systems in the field of robotics.

  4. Lift enhancement by trapped vortex

    Science.gov (United States)

    Rossow, Vernon J.

    1992-01-01

    The viewgraphs and discussion of lift enhancement by trapped vortex are provided. Efforts are continuously being made to find simple ways to convert wings of aircraft from an efficient cruise configuration to one that develops the high lift needed during landing and takeoff. The high-lift configurations studied here consist of conventional airfoils with a trapped vortex over the upper surface. The vortex is trapped by one or two vertical fences that serve as barriers to the oncoming stream and as reflection planes for the vortex and the sink that form a separation bubble on top of the airfoil. Since the full three-dimensional unsteady flow problem over the wing of an aircraft is so complicated that it is hard to get an understanding of the principles that govern the vortex trapping process, the analysis is restricted here to the flow field illustrated in the first slide. It is assumed that the flow field between the two end plates approximates a streamwise strip of the flow over a wing. The flow between the endplates and about the airfoil consists of a spanwise vortex located between the suction orifices in the endplates. The spanwise fence or spoiler located near the nose of the airfoil serves to form a separated flow region and a shear layer. The vorticity in the shear layer is concentrated into the vortex by withdrawal of fluid at the suction orifices. As the strength of the vortex increases with time, it eventually dominates the flow in the separated region so that a shear or vertical layer is no longer shed from the tip of the fence. At that point, the vortex strength is fixed and its location is such that all of the velocity contributions at its center sum to zero thereby making it an equilibrium point for the vortex. The results of a theoretical analysis of such an idealized flow field are described.

  5. Protocolized hyperventilation enhances electroconvulsive therapy.

    Science.gov (United States)

    de Arriba-Arnau, Aida; Dalmau, Antonia; Soria, Virginia; Salvat-Pujol, Neus; Ribes, Carmina; Sánchez-Allueva, Ana; Menchón, José Manuel; Urretavizcaya, Mikel

    2017-08-01

    Hyperventilation is recommended in electroconvulsive therapy (ECT) to enhance seizures and to increase patients' safety. However, more evidence is needed regarding its effects and the optimum method of application. This prospective study involving 21 subjects compared two procedures, protocolized hyperventilation (PHV) and hyperventilation as usual (HVau), applied to the same patient in two consecutive sessions. Transcutaneous partial pressure of carbon dioxide (TcPCO 2 ) was measured throughout all sessions. Ventilation parameters, hemodynamic measures, seizure characteristics, and side effects were also explored. PHV resulted in lower TcPCO 2 after hyperventilation (p=.008) and over the whole session (p=.035). The lowest TcPCO 2 was achieved after voluntary hyperventilation. Changes in TcPCO 2 from baseline showed differences between HVau and PHV at each session time-point (all p<.05). Between- and within-subjects factors were statistically significant in a general linear model. Seizure duration was greater in PHV sessions (p=.028), without differences in other seizure quality parameters or adverse effects. Correlations were found between hypocapnia induction and seizure quality indexes. Secondary outcomes could be underpowered. PHV produces hypocapnia before the stimulus, modifies patients' TcPCO 2 values throughout the ECT session and lengthens seizure duration. Voluntary hyperventilation is the most important part of the PHV procedure with respect to achieving hypocapnia. A specific ventilation approach, CO 2 quantification and monitoring may be advisable in ECT. PHV is easy to apply in daily clinical practice and does not imply added costs. Ventilation management has promising effects in terms of optimizing ECT technique. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Oscillatory Reinstatement Enhances Declarative Memory.

    Science.gov (United States)

    Javadi, Amir-Homayoun; Glen, James C; Halkiopoulos, Sara; Schulz, Mei; Spiers, Hugo J

    2017-10-11

    Declarative memory recall is thought to involve the reinstatement of neural activity patterns that occurred previously during encoding. Consistent with this view, greater similarity between patterns of activity recorded during encoding and retrieval has been found to predict better memory performance in a number of studies. Recent models have argued that neural oscillations may be crucial to reinstatement for successful memory retrieval. However, to date, no causal evidence has been provided to support this theory, nor has the impact of oscillatory electrical brain stimulation during encoding and retrieval been assessed. To explore this we used transcranial alternating current stimulation over the left dorsolateral prefrontal cortex of human participants [ n = 70, 45 females; age mean (SD) = 22.12 (2.16)] during a declarative memory task. Participants received either the same frequency during encoding and retrieval (60-60 or 90-90 Hz) or different frequencies (60-90 or 90-60 Hz). When frequencies matched there was a significant memory improvement (at both 60 and 90 Hz) relative to sham stimulation. No improvement occurred when frequencies mismatched. Our results provide support for the role of oscillatory reinstatement in memory retrieval. SIGNIFICANCE STATEMENT Recent neurobiological models of memory have argued that large-scale neural oscillations are reinstated to support successful memory retrieval. Here we used transcranial alternating current stimulation (tACS) to test these models. tACS has recently been shown to induce neural oscillations at the frequency stimulated. We stimulated over the left dorsolateral prefrontal cortex during a declarative memory task involving learning a set of words. We found that tACS applied at the same frequency during encoding and retrieval enhances memory. We also find no difference between the two applied frequencies. Thus our results are consistent with the proposal that reinstatement of neural oscillations during retrieval

  7. Enhanced seismic criteria for piping

    International Nuclear Information System (INIS)

    Touboul, F. . E-mail francoise.touboul@cea.fr; Blay, N.; Sollogoub, P.; Chapuliot, S.

    2006-01-01

    In situ or laboratory experiments have shown that piping systems exhibit satisfactory seismic behavior. Seismic motion is not severe enough to significantly damage piping systems unless large differential motions of anchorage are imposed. Nevertheless, present design criteria for piping are very severe and require a large number of supports, which creates overly rigid piping systems. CEA, in collaboration with EDF, FRAMATOME and IRSN, has launched a large R and D program on enhanced design methods which will be less severe, but still conservative, and compatible with defect justification during operation. This paper presents the background of the R and D work on this matter, and CEA proposed equations. Our approach is based on the difference between the real behavior (or the best estimated computed one) with the one supposed by codified methods. Codified criteria are applied on an elastically calculated behavior that can be significantly different from the real one: the effect of plasticity may be very meaningful, even with low incursion in the plastic domain. Moreover, and particularly in piping systems, the elastic follow-up effect affects stress distribution for both seismic and thermal loads. For seismic load, we have proposed to modify the elastic moment limitation, based on the interpretation of experimental results on piping systems. The methods have been validated on more industrial cases, and some of the consequences of the changes have been studied: modification of the drawings and of the number of supports, global displacements, forces in the supports, stability of potential defects, etc. The basic aim of the studies undertaken is to make a decision on the stress classification problem, one that is not limited to seismic induced stresses, and to propose simplified methods for its solution

  8. Enhancing critical current density of cuprate superconductors

    Science.gov (United States)

    Chaudhari, Praveen

    2015-06-16

    The present invention concerns the enhancement of critical current densities in cuprate superconductors. Such enhancement of critical current densities include using wave function symmetry and restricting movement of Abrikosov (A) vortices, Josephson (J) vortices, or Abrikosov-Josephson (A-J) vortices by using the half integer vortices associated with d-wave symmetry present in the grain boundary.

  9. Recommender Systems in Technology Enhanced Learning

    NARCIS (Netherlands)

    Manouselis, Nikos; Drachsler, Hendrik; Verbert, Katrien; Santos, Olga

    2010-01-01

    Manouselis, N., Drachsler, H., Verbert, K., & Santos, C. S. (Eds.) (2010). Recommender System in Technology Enhanced Learning. Elsevier Procedia Computer Science: Volume 1, Issue 2. Proceedings of the 1st Workshop on Recommender Systems for Technology Enhanced Learning (RecSysTEL). September, 29-30,

  10. Sickle erythrocytes enhance phenylephrine and histamine ...

    African Journals Online (AJOL)

    Sickle erythrocytes enhance phenylephrine and histamine contractions of isolated rabbit carotid arteries. ... enhancement of histamine contractions, compared with phenylephrine (in AS and SS), suggests a possible role for histamine in the increased vascular tone and vaso-occlusive crisis in sickle cell disease.

  11. Learner Ownership of Technology-Enhanced Learning

    Science.gov (United States)

    Dommett, Eleanor J.

    2018-01-01

    Purpose: This paper aims to examine the different ways in which learners may have ownership over technology-enhanced learning by reflecting on technical, legal and psychological ownership. Design/methodology/approach: The paper uses a variety of examples of technology-enhanced learning ranging from open-source software to cloud storage to discuss…

  12. Towards a Moderate Stance on Human Enhancement

    Directory of Open Access Journals (Sweden)

    Nikil Mukerji

    2014-05-01

    Full Text Available In this essay, we argue against radical ethical views about human enhancement that either dismiss or endorse it tout court. Instead, we advocate the moderate stance that issues of enhancement should be examined with an open mind and on a case-by-case basis. To make this view plausible, we offer three reasons. The first lies in the fact that it is difficult to delineate enhancement conceptually, which makes it hard to argue for general ethical conclusions about it. The second is that an appropriate view of the edifice of moral theory suggests that tenable moral judgements about human enhancement are the result of a careful consideration of the pros and cons that attach to the use of a specific enhancement technology. Lastly, we show that important normative factors in the enhancement debate can be used both in arguments for and in arguments against enhancement. The bottom line of our discussion is that we should treat issues of human enhancement like we do any other ethical issue, viz. by weighing up the reasons pro and con.

  13. Enhanced Cooperation under the Lisbon Treaty

    NARCIS (Netherlands)

    Groenendijk, Nico

    2011-01-01

    Enhanced cooperation is often regarded as being a way out of EU decision-making deadlock and as a major possibility of proceeding with European integration in selected areas. Although the mechanism has been in place since the Treaty of Amsterdam, enhanced cooperation has only recently become a

  14. Surface-enhanced Raman spectroscopy: nonlocal limitations

    DEFF Research Database (Denmark)

    Toscano, Giuseppe; Raza, Søren; Xiao, Sanshui

    2012-01-01

    for our understanding of surface-enhanced Raman spectroscopy (SERS). The intrinsic length scale of the electron gas serves to smear out assumed field singularities, leaving the SERS enhancement factor finite, even for geometries with infinitely sharp features. For silver nanogroove structures, mimicked...

  15. Video enhancement : content classification and model selection

    NARCIS (Netherlands)

    Hu, H.

    2010-01-01

    The purpose of video enhancement is to improve the subjective picture quality. The field of video enhancement includes a broad category of research topics, such as removing noise in the video, highlighting some specified features and improving the appearance or visibility of the video content. The

  16. Enhanced living environments from models to technologies

    CERN Document Server

    Dobre, Ciprian; Ganchev, Ivan; Garcia, Nuno; Goleva, Rossitza Ivanova

    2017-01-01

    Enhanced living environments employ information and communications technologies to support true ambient assisted living for people with disabilities. This book provides an overview of today's architectures, techniques, protocols, components, and cloud-based solutions related to ambient assisted living and enhanced living environments.

  17. Enhancement of retronasal odors by taste.

    Science.gov (United States)

    Green, Barry G; Nachtigal, Danielle; Hammond, Samuel; Lim, Juyun

    2012-01-01

    Psychophysical studies of interactions between retronasal olfaction and taste have focused most often on the enhancement of tastes by odors, which has been attributed primarily to a response bias (i.e., halo dumping). Based upon preliminary evidence that retronasal odors could also be enhanced by taste, the present study measured both forms of enhancement using appropriate response categories. In the first experiment, subjects rated taste ("sweet," "sour," "salty," and "bitter") and odor ("other") intensity for aqueous samples of 3 tastants (sucrose, NaCl, and citric acid) and 3 odorants (vanillin, citral, and furaneol), both alone and in taste-odor mixtures. The results showed that sucrose, but not the other taste stimuli, significantly increased the perceived intensity of all 3 odors. Enhancement of tastes by odors was inconsistent and generally weaker than enhancement of odors by sucrose. A second experiment used a flavored beverage and a custard dessert to test whether the findings from the first experiment would hold for the perception of actual foods. Adding sucrose significantly enhanced the intensity of "cherry" and "vanilla" flavors, whereas adding vanillin did not significantly enhance the intensity of sweetness. It is proposed that enhancement of retronasal odors by a sweet stimulus results from an adaptive sensory mechanism that serves to increase the salience of the flavor of nutritive foods. © The Author 2011. Published by Oxford University Press. All rights reserved.

  18. Performance-Enhancing Drugs: Know the Risks

    Science.gov (United States)

    ... edge by taking muscle-building supplements or other performance-enhancing drugs? Learn how these drugs work and how they can affect your health. By ... to testosterone and estradiol in both men and women. Andro is available legally ... use as a performance-enhancing drug is illegal in the United States. ...

  19. Surfactant enhanced non-classical extraction

    International Nuclear Information System (INIS)

    Szymanowski, J.

    2000-01-01

    Surfactant enhanced non-classical extractions are presented and discussed. They include micellar enhanced ultrafiltration and cloud point extraction. The ideas of the processes are given and the main features are presented. They are compared to the classical solvent extraction. The fundamental of micellar solutions and their solubilisation abilities are also discussed. (author)

  20. Infrared image enhancement with learned features

    Science.gov (United States)

    Fan, Zunlin; Bi, Duyan; Ding, Wenshan

    2017-11-01

    Due to the variation of imaging environment and limitations of infrared imaging sensors, infrared images usually have some drawbacks: low contrast, few details and indistinct edges. Hence, to promote the applications of infrared imaging technology, it is essential to improve the qualities of infrared images. To enhance image details and edges adaptively, we propose an infrared image enhancement method under the proposed image enhancement scheme. On the one hand, on the assumption of high-quality image taking more evident structure singularities than low-quality images, we propose an image enhancement scheme that depends on the extractions of structure features. On the other hand, different from the current image enhancement algorithms based on deep learning networks that try to train and build the end-to-end mappings on improving image quality, we analyze the significance of first layer in Stacked Sparse Denoising Auto-encoder and propose a novel feature extraction for the proposed image enhancement scheme. Experiment results prove that the novel feature extraction is free from some artifacts on the edges such as blocking artifacts, ;gradient reversal;, and pseudo contours. Compared with other enhancement methods, the proposed method achieves the best performance in infrared image enhancement.

  1. Strengthening Research Capacity to Enhance Natural Resources ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    ... to Enhance Natural Resources Management and Improve Rural Livelihoods ... and contribute to the food and income security of the rural poor by enhancing the ... of its 2017 call for proposals to establish Cyber Policy Centres in the Global South. ... partnering on a new initiative, aimed at reducing the emerging risk that.

  2. 23 CFR 710.511 - Transportation enhancements.

    Science.gov (United States)

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false Transportation enhancements. 710.511 Section 710.511 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RIGHT-OF-WAY AND ENVIRONMENT RIGHT-OF-WAY AND REAL ESTATE Property Acquisition Alternatives § 710.511 Transportation enhancements. (a...

  3. Leadership Enhancement of Rural Women. | Patwardhan | Gender ...

    African Journals Online (AJOL)

    The study aimed at developing a training program for enhancement of women leadership and executing and evaluating its effect. The Enhancement of Women Leadership Program (EWLP) was developed, which consists of five broad dimensions as Nurturing Intelligence, Self Development, Developing Leadership Skills, ...

  4. Possible edge effect in enhanced network

    Energy Technology Data Exchange (ETDEWEB)

    Jones, H P; Brown, D R [National Aeronautics and Space Administration, Greenbelt, Md. (USA). Goddard Space Flight Center

    1977-05-01

    K-line observations of enhanced network taken with the NASA/SPO Multichannel Spectrometer on 28 September 1975 in support of OSO-8 are discussed. The data show a correlation between core brightness and asymmetry for spatial scans which cross enhanced network boundaries. The implications of this result concerning mass flow in and near supergranule boundaries are discussed.

  5. Input Enhancement and L2 Question Formation.

    Science.gov (United States)

    White, Lydia; And Others

    1991-01-01

    Investigated the extent to which form-focused instruction and corrective feedback (i.e., "input enhancement"), provided within a primarily communicative program, contribute to learners' accuracy in question formation. Study results are interpreted as evidence that input enhancement can bring about genuine changes in learners' interlanguage…

  6. Self-Enhancing Illusions among Chinese Schoolchildren.

    Science.gov (United States)

    Falbo, Toni; And Others

    1997-01-01

    Demonstrates that East Asian children (EAC) do engage in some forms of self-enhancing illusions. Responses from 4,000 elementary school students reveal EACs see themselves as possessing more positive attributes than others. Variations in self-enhancing illusions were found for age, gender, and region of residence. Results are discussed in terms of…

  7. Mechanisms of enhanced lung injury during sepsis

    DEFF Research Database (Denmark)

    Czermak, B J; Breckwoldt, M; Ravage, Z B

    1999-01-01

    . Enhanced lung injury was associated with increased accumulation of neutrophils in lung, enhanced production of CXC chemokines (but not tumor necrosis factor-alpha) in bronchoalveolar lavage fluids, and increased expression of lung vascular intercellular adhesion molecule-1 (ICAM-1). Complement depletion...

  8. Surfactant enhanced non-classical extraction

    International Nuclear Information System (INIS)

    Szymanowski, J.

    1999-01-01

    Surfactant enhanced non-classical extractions are presented and discussed. They include micellar enhanced ultrafiltration and cloud point extraction. The ideas of the processes are given and the main features are presented. They are compared to the classical solvent extraction. The fundamental of micellar solutions and their solubilization abilities are also discussed. (author)

  9. Overhauser-enhanced MR imaging (OMRI)

    DEFF Research Database (Denmark)

    Golman, K; Leunbach, I; Ardenkjaer-Larsen, JH

    1998-01-01

    Purpose. To evaluate a new single-electron contrast agent for Overhauser-enhanced MR imaging. The contrast agents that are currently available give enhancement factors that are too low to make the technique a valid option for routine clinical use. Material and Methods. MR images were generated di...

  10. Hopping Conductivity Enhanced by Microwave Radiation

    International Nuclear Information System (INIS)

    Ovadyahu, Z

    2012-01-01

    Hopping conductivity is enhanced when exposed to microwave (MW) fields. Data taken on several Anderson-localized systems and granular-aluminium are presented to illustrate the generality of the phenomenon. It is suggested that the effect is due to a field-enhanced hopping, which is the ac version of a non-ohmic effect familiar from studies in the dc transport regime.

  11. Enhance Video Film using Retnix method

    Science.gov (United States)

    Awad, Rasha; Al-Zuky, Ali A.; Al-Saleh, Anwar H.; Mohamad, Haidar J.

    2018-05-01

    An enhancement technique used to improve the studied video quality. Algorithms like mean and standard deviation are used as a criterion within this paper, and it applied for each video clip that divided into 80 images. The studied filming environment has different light intensity (315, 566, and 644Lux). This different environment gives similar reality to the outdoor filming. The outputs of the suggested algorithm are compared with the results before applying it. This method is applied into two ways: first, it is applied for the full video clip to get the enhanced film; second, it is applied for every individual image to get the enhanced image then compiler them to get the enhanced film. This paper shows that the enhancement technique gives good quality video film depending on a statistical method, and it is recommended to use it in different application.

  12. Speech enhancement on smartphone voice recording

    International Nuclear Information System (INIS)

    Atmaja, Bagus Tris; Farid, Mifta Nur; Arifianto, Dhany

    2016-01-01

    Speech enhancement is challenging task in audio signal processing to enhance the quality of targeted speech signal while suppress other noises. In the beginning, the speech enhancement algorithm growth rapidly from spectral subtraction, Wiener filtering, spectral amplitude MMSE estimator to Non-negative Matrix Factorization (NMF). Smartphone as revolutionary device now is being used in all aspect of life including journalism; personally and professionally. Although many smartphones have two microphones (main and rear) the only main microphone is widely used for voice recording. This is why the NMF algorithm widely used for this purpose of speech enhancement. This paper evaluate speech enhancement on smartphone voice recording by using some algorithms mentioned previously. We also extend the NMF algorithm to Kulback-Leibler NMF with supervised separation. The last algorithm shows improved result compared to others by spectrogram and PESQ score evaluation. (paper)

  13. Metal plasmon enhanced europium complex luminescence

    International Nuclear Information System (INIS)

    Liu Feng; Aldea, Gabriela; Nunzi, Jean-Michel

    2010-01-01

    The plasmon enhanced luminescence of a rare-earth complex Tris(6, 6, 7, 7, 8, 8, 8-heptafluoro-2, 2-dimethyl-3, 5-octanedionato) europium (Eu(fod) 3 ) was investigated. A polyvinyl alcohol (PVA) thin film was successfully adopted as a spacer to separate the Eu complex from the silver island film (SIF), and five-fold enhancement of the radiative decay rate of the Eu complex on SIF was demonstrated based on the luminescence intensity and lifetime measurement. Investigation of the distance dependent luminescence indicates that 7 nm is an optimal distance for SIF enhanced Eu luminescence. Plasmon enhanced rare-earth luminescence based on an organic film spacer would find potential applications in plasmon enhanced organic light emitting diode (OLED) devices.

  14. Self-enhancement: Conceptualization and Assessment

    Directory of Open Access Journals (Sweden)

    Joachim I. Krueger

    2017-11-01

    Full Text Available Self-enhancement bias is conventionally construed as an unwarranted social comparison in social psychology and a misperception of social reality in personality psychology. Researchers in both fields rely heavily on discrepancy scores to represent self-enhancement and fail to distinguish between a general tendency or bias to self-enhance and a self-enhancement error, or 'false' perception of own excellence. We critically review prominent discrepancy measures and then propose a decision-theoretic alternative that [a] mitigates confounds between self-positivity and self-superiority, [b] separates error from bias, and [c] discourages reliance on measures that reify self-enhancement as a stable personality trait. To evaluate our hypotheses, we re-analyze data collected in our laboratory and perform a series of simulation studies. We share these materials with interested researchers.

  15. Source memory enhancement for emotional words.

    Science.gov (United States)

    Doerksen, S; Shimamura, A P

    2001-03-01

    The influence of emotional stimuli on source memory was investigated by using emotionally valenced words. The words were colored blue or yellow (Experiment 1) or surrounded by a blue or yellow frame (Experiment 2). Participants were asked to associate the words with the colors. In both experiments, emotionally valenced words elicited enhanced free recall compared with nonvalenced words; however, recognition memory was not affected. Source memory for the associated color was also enhanced for emotional words, suggesting that even memory for contextual information is benefited by emotional stimuli. This effect was not due to the ease of semantic clustering of emotional words because semantically related words were not associated with enhanced source memory, despite enhanced recall (Experiment 3). It is suggested that enhancement resulted from facilitated arousal or attention, which may act to increase organization processes important for source memory.

  16. Human Enhancement and the Story of Job.

    Science.gov (United States)

    Agar, Nicholas; McDonald, Johnny

    2017-07-01

    This article explores some implications of the concept of transformative change for the debate about human enhancement. A transformative change is understood to be one that significantly alters the value an individual places on his or her experiences or achievements. The clearest examples of transformative change come from science fiction, but the concept can be illuminatingly applied to the enhancement debate. We argue that it helps to expose a threat from too much enhancement to many of the things that make human lives valuable. Among the things threated by enhancement are our relationships with other human beings. The potential to lose these relationships provides a compelling reason for almost all humans to reject too much enhancement.

  17. Enhanced Recovery in Thoracic Surgery: A Review

    Directory of Open Access Journals (Sweden)

    Vesna D. Dinic

    2018-02-01

    Full Text Available The main goal of enhanced recovery program after thoracic surgery is to minimize stress response, reduce postoperative pulmonary complications, and improve patient outcome, which will in addition decrease hospital stay and reduce hospital costs. As minimally invasive technique, video-assisted thoracoscopic surgery represents an important element of enhanced recovery program in thoracic surgery. Anesthetic management during preoperative, intraoperative and postoperative period is essential for the enhanced recovery. In the era of enhanced recovery protocols, non-intubated thoracoscopic procedures present a step forward. This article focuses on the key elements of the enhanced recovery program in thoracic surgery. Having reviewed recent literature, the authors highlight potential procedures and techniques that might be incorporated into the program.

  18. Gabor filter based fingerprint image enhancement

    Science.gov (United States)

    Wang, Jin-Xiang

    2013-03-01

    Fingerprint recognition technology has become the most reliable biometric technology due to its uniqueness and invariance, which has been most convenient and most reliable technique for personal authentication. The development of Automated Fingerprint Identification System is an urgent need for modern information security. Meanwhile, fingerprint preprocessing algorithm of fingerprint recognition technology has played an important part in Automatic Fingerprint Identification System. This article introduces the general steps in the fingerprint recognition technology, namely the image input, preprocessing, feature recognition, and fingerprint image enhancement. As the key to fingerprint identification technology, fingerprint image enhancement affects the accuracy of the system. It focuses on the characteristics of the fingerprint image, Gabor filters algorithm for fingerprint image enhancement, the theoretical basis of Gabor filters, and demonstration of the filter. The enhancement algorithm for fingerprint image is in the windows XP platform with matlab.65 as a development tool for the demonstration. The result shows that the Gabor filter is effective in fingerprint image enhancement technology.

  19. Gold nanodisc arrays as near infrared metal-enhanced fluorescence platforms with tuneable enhancement factors

    KAUST Repository

    Pang, J.; Theodorou, I. G.; Centeno, A.; Petrov, P. K.; Alford, N. M.; Ryan, M. P.; Xie, F.

    2016-01-01

    Metal enhanced fluorescence (MEF) is a physical effect through which the near-field interaction of fluorophores with metallic nanoparticles can lead to large fluorescence enhancement. MEF can be exploited in many fluorescence-based biomedical applications, with potentially significant improvement in detection sensitivity and contrast enhancement. Offering lower autofluorescence and minimal photoinduced damage, the development of effective and multifunctional MEF platforms in the near-infrared (NIR) region, is particularly desirable. In this work, the enhancement of NIR fluorescence caused by interaction with regular arrays of cylindrical gold (Au) nanoparticles (nanodiscs), fabricated through nanosphere lithography, is reported. Significant MEF of up to 235 times is obtained, with tuneable enhancement factors. The effect of array structure on fluorescence enhancement is investigated by semi-quantitatively de-convoluting excitation enhancement from emission enhancement, and modelling the local electric field enhancement. By considering arrays of Au nanodiscs with the same extinction maximum, it is shown that the excitation enhancement, due to increased electric field, is not significantly different for the particle sizes and separation distances considered. Rather, it is seen that the emission from the fluorophore is strongly enhanced, and is dependent on the topography, in particular particle size. The results show that the structural characteristics of Au nanodisc arrays can be manipulated to tune their enhancement factor, and hence their sensitivity.

  20. Gold nanodisc arrays as near infrared metal-enhanced fluorescence platforms with tuneable enhancement factors

    KAUST Repository

    Pang, J.

    2016-12-28

    Metal enhanced fluorescence (MEF) is a physical effect through which the near-field interaction of fluorophores with metallic nanoparticles can lead to large fluorescence enhancement. MEF can be exploited in many fluorescence-based biomedical applications, with potentially significant improvement in detection sensitivity and contrast enhancement. Offering lower autofluorescence and minimal photoinduced damage, the development of effective and multifunctional MEF platforms in the near-infrared (NIR) region, is particularly desirable. In this work, the enhancement of NIR fluorescence caused by interaction with regular arrays of cylindrical gold (Au) nanoparticles (nanodiscs), fabricated through nanosphere lithography, is reported. Significant MEF of up to 235 times is obtained, with tuneable enhancement factors. The effect of array structure on fluorescence enhancement is investigated by semi-quantitatively de-convoluting excitation enhancement from emission enhancement, and modelling the local electric field enhancement. By considering arrays of Au nanodiscs with the same extinction maximum, it is shown that the excitation enhancement, due to increased electric field, is not significantly different for the particle sizes and separation distances considered. Rather, it is seen that the emission from the fluorophore is strongly enhanced, and is dependent on the topography, in particular particle size. The results show that the structural characteristics of Au nanodisc arrays can be manipulated to tune their enhancement factor, and hence their sensitivity.

  1. Carbon dioxide efficiency of terrestrial enhanced weathering.

    Science.gov (United States)

    Moosdorf, Nils; Renforth, Phil; Hartmann, Jens

    2014-05-06

    Terrestrial enhanced weathering, the spreading of ultramafic silicate rock flour to enhance natural weathering rates, has been suggested as part of a strategy to reduce global atmospheric CO2 levels. We budget potential CO2 sequestration against associated CO2 emissions to assess the net CO2 removal of terrestrial enhanced weathering. We combine global spatial data sets of potential source rocks, transport networks, and application areas with associated CO2 emissions in optimistic and pessimistic scenarios. The results show that the choice of source rocks and material comminution technique dominate the CO2 efficiency of enhanced weathering. CO2 emissions from transport amount to on average 0.5-3% of potentially sequestered CO2. The emissions of material mining and application are negligible. After accounting for all emissions, 0.5-1.0 t CO2 can be sequestered on average per tonne of rock, translating into a unit cost from 1.6 to 9.9 GJ per tonne CO2 sequestered by enhanced weathering. However, to control or reduce atmospheric CO2 concentrations substantially with enhanced weathering would require very large amounts of rock. Before enhanced weathering could be applied on large scales, more research is needed to assess weathering rates, potential side effects, social acceptability, and mechanisms of governance.

  2. Spectroscopic enhancement in nanoparticles embedded glasses

    Energy Technology Data Exchange (ETDEWEB)

    Sahar, M. R., E-mail: mrahim057@gmail.com; Ghoshal, S. K., E-mail: mrahim057@gmail.com [Advanced Optical Material Research Group, Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, 81310, Skudai, Johor Bahru, Johor (Malaysia)

    2014-09-25

    This presentation provides an overview of the recent progress in the enhancement of the spectroscopic characteristics of the glass embedded with nanoparticles (NPs). Some of our research activities with few significantly new results are highlighted and facilely analyzed. The science and technology dealing with the manipulation of the physical properties of rare earth doped inorganic glasses by embedding metallic NPs or nanoclusters produce the so-called 'nanoglass'. Meanwhile, the spectroscopic enhancement relates the intensity of the luminescence measured at certain transition. The enhancement which expectedly due to the 'plasmonics wave' (referring to the coherent coupling of photons to free electron oscillations called plasmon) occurs at the interface between a conductor and a dielectric. Plasmonics being an emerging concept in advanced optical material of nanophotonics has given this material the ability to exploit the optical response at nanoscale and opened up a new avenue in metal-based glass optics. There is a vast array of plasmonic NPs concepts yet to be explored, with applications spanning solar cells, (bio) sensing, communications, lasers, solid-state lighting, waveguides, imaging, optical data transfer, display and even bio-medicine. Localized surface plasmon resonance (LSPR) can enhance the optical response of nanoglass by orders of magnitude as observed. The luminescence enhancement and surface enhanced Raman scattering (SERS) are new paradigm of research. The enhancement of luminescence due to the influence of metallic NPs is the recurring theme of this paper.

  3. Optimizing laser crater enhanced Raman spectroscopy.

    Science.gov (United States)

    Lednev, V N; Sdvizhenskii, P A; Grishin, M Ya; Filichkina, V A; Shchegolikhin, A N; Pershin, S M

    2018-03-20

    Raman signal enhancement by laser crater production was systematically studied for 785 nm continuous wave laser pumping. Laser craters were produced in L-aspartic acid powder by a nanosecond pulsed solid state neodymium-doped yttrium aluminum garnet laser (532 nm, 8 ns, 1 mJ/pulse), while Raman spectra were then acquired by using a commercial spectrometer with 785 nm laser beam pumping. The Raman signal enhancement effect was studied in terms of the number of ablating pulses used, the lens-to-sample distance, and the crater-center-laser-spot offset. The influence of the experiment parameters on Raman signal enhancement was studied for different powder materials. Maximum Raman signal enhancement reached 11 fold for loose powders but decreased twice for pressed tablets. Raman signal enhancement was demonstrated for several diverse powder materials like gypsum or ammonium nitrate with better results achieved for the samples tending to give narrow and deep craters upon the laser ablation stage. Alternative ways of cavity production (steel needle tapping and hole drilling) were compared with the laser cratering technique in terms of Raman signal enhancement. Drilling was found to give the poorest enhancement of the Raman signal, while both laser ablation and steel needle tapping provided comparable results. Here, we have demonstrated for the first time, to the best of our knowledge, that a Raman signal can be enhanced 10 fold with the aid of simple cavity production by steel needle tapping in rough highly reflective materials. Though laser crater enhancement Raman spectroscopy requires an additional pulsed laser, this technique is more appropriate for automatization compared to the needle tapping approach.

  4. Autoimmune pancreatitis: Assessment of the enhanced duct sign on multiphase contrast-enhanced computed tomography

    International Nuclear Information System (INIS)

    Kawai, Yuichi; Suzuki, Kojiro; Itoh, Shigeki; Takada, Akira; Mori, Yoshine; Naganawa, Shinji

    2012-01-01

    Purpose: To assess the usefulness of the computed tomography (CT) finding of main pancreatic duct (MPD) wall enhancement, termed the “enhanced duct sign”, for diagnosis of autoimmune pancreatitis (AIP) in comparison with diagnosis of pancreatic carcinoma and chronic pancreatitis. Materials and methods: Two radiologists independently evaluated the presence or absence of the enhanced duct sign on multiphase contrast-enhanced CT in patients with AIP (n = 55), pancreatic carcinoma (n = 50), and chronic pancreatitis (n = 50). The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of AIP were calculated. In patients demonstrating the enhanced duct sign, additional findings were evaluated by consensus. Results: The enhanced duct sign was more frequently observed in patients with AIP (37/55, 67%) than in patients with pancreatic carcinoma (5/50, 10%) or chronic pancreatitis (0/50, 0%) (P < 0.05). The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of the finding were 0.67, 0.95, 0.85, 0.88, and 0.84, respectively. In AIP, the lumen within the enhanced duct was completely or partially invisible in 29 of 37 (78%) patients, and the enhanced duct was observed within the affected pancreatic parenchyma in 35 of 37 (95%) patients. In pancreatic carcinoma, the lumen within the enhanced duct was visible in all patients (5/5, 100%), and the enhanced duct was observed downstream of the tumor (5/5, 100%). Conclusion: The enhanced duct sign is highly specific of AIP.

  5. Autoimmune pancreatitis: Assessment of the enhanced duct sign on multiphase contrast-enhanced computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Kawai, Yuichi, E-mail: kawai.yuichi@a.mbox.nagoya-u.ac.jp [Department of Radiology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550 (Japan); Suzuki, Kojiro, E-mail: kojiro@med.nagoya-u.ac.jp [Department of Radiology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550 (Japan); Itoh, Shigeki, E-mail: shigeito@nagoya-1st.jrc.or.jp [Department of Diagnostic Radiology, Japan Red Cross Nagoya Daiichi Hospital, 3-35 Michishita-cho, Nakamura-ku, Nagoya 453-8511 (Japan); Takada, Akira, E-mail: takadaa@med.nagoya-u.ac.jp [Department of Radiology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550 (Japan); Mori, Yoshine, E-mail: yoshine@med.nagoya-u.ac.jp [Department of Radiology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550 (Japan); Naganawa, Shinji, E-mail: naganawa@med.nagoya-u.ac.jp [Department of Radiology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550 (Japan)

    2012-11-15

    Purpose: To assess the usefulness of the computed tomography (CT) finding of main pancreatic duct (MPD) wall enhancement, termed the 'enhanced duct sign', for diagnosis of autoimmune pancreatitis (AIP) in comparison with diagnosis of pancreatic carcinoma and chronic pancreatitis. Materials and methods: Two radiologists independently evaluated the presence or absence of the enhanced duct sign on multiphase contrast-enhanced CT in patients with AIP (n = 55), pancreatic carcinoma (n = 50), and chronic pancreatitis (n = 50). The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of AIP were calculated. In patients demonstrating the enhanced duct sign, additional findings were evaluated by consensus. Results: The enhanced duct sign was more frequently observed in patients with AIP (37/55, 67%) than in patients with pancreatic carcinoma (5/50, 10%) or chronic pancreatitis (0/50, 0%) (P < 0.05). The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of the finding were 0.67, 0.95, 0.85, 0.88, and 0.84, respectively. In AIP, the lumen within the enhanced duct was completely or partially invisible in 29 of 37 (78%) patients, and the enhanced duct was observed within the affected pancreatic parenchyma in 35 of 37 (95%) patients. In pancreatic carcinoma, the lumen within the enhanced duct was visible in all patients (5/5, 100%), and the enhanced duct was observed downstream of the tumor (5/5, 100%). Conclusion: The enhanced duct sign is highly specific of AIP.

  6. Acoustic Purcell Effect for Enhanced Emission

    KAUST Repository

    Landi, Maryam; Zhao, Jiajun; Prather, Wayne E.; Wu, Ying; Zhang, Likun

    2018-01-01

    We observe that our experimentally measured emission power enhancement of a speaker inside a previously proposed metacavity agrees with our numerically calculated enhancement of the density of states (DOS) of the source-cavity system. We interpret the agreement by formulating a relation between the emitted sound power and the acoustic DOS. The formulation is an analog to Fermi’s golden rule in quantum emission. The formulation complements the radiation impedance theory in traditional acoustics for describing sound emission. Our study bridges the gap between acoustic DOS and the acoustic Purcell effect for sound emission enhancement.

  7. Enhancing Rotational Diffusion Using Oscillatory Shear

    KAUST Repository

    Leahy, Brian D.

    2013-05-29

    Taylor dispersion - shear-induced enhancement of translational diffusion - is an important phenomenon with applications ranging from pharmacology to geology. Through experiments and simulations, we show that rotational diffusion is also enhanced for anisotropic particles in oscillatory shear. This enhancement arises from variations in the particle\\'s rotation (Jeffery orbit) and depends on the strain amplitude, rate, and particle aspect ratio in a manner that is distinct from the translational diffusion. This separate tunability of translational and rotational diffusion opens the door to new techniques for controlling positions and orientations of suspended anisotropic colloids. © 2013 American Physical Society.

  8. Acoustic Purcell Effect for Enhanced Emission

    KAUST Repository

    Landi, Maryam

    2018-03-13

    We observe that our experimentally measured emission power enhancement of a speaker inside a previously proposed metacavity agrees with our numerically calculated enhancement of the density of states (DOS) of the source-cavity system. We interpret the agreement by formulating a relation between the emitted sound power and the acoustic DOS. The formulation is an analog to Fermi’s golden rule in quantum emission. The formulation complements the radiation impedance theory in traditional acoustics for describing sound emission. Our study bridges the gap between acoustic DOS and the acoustic Purcell effect for sound emission enhancement.

  9. Enhancement of Retronasal Odors by Taste

    OpenAIRE

    Green, Barry G.; Nachtigal, Danielle; Hammond, Samuel; Lim, Juyun

    2011-01-01

    Psychophysical studies of interactions between retronasal olfaction and taste have focused most often on the enhancement of tastes by odors, which has been attributed primarily to a response bias (i.e., halo dumping). Based upon preliminary evidence that retronasal odors could also be enhanced by taste, the present study measured both forms of enhancement using appropriate response categories. In the first experiment, subjects rated taste (“sweet,” “sour,” “salty,” and “bitter”) and odor (“ot...

  10. Enhancer evolution across 20 mammalian species

    DEFF Research Database (Denmark)

    Villar, Diego; Berthelot, Camille; Aldridge, Sarah

    2015-01-01

    The mammalian radiation has corresponded with rapid changes in noncoding regions of the genome, but we lack a comprehensive understanding of regulatory evolution in mammals. Here, we track the evolution of promoters and enhancers active in liver across 20 mammalian species from six diverse orders...... by profiling genomic enrichment of H3K27 acetylation and H3K4 trimethylation. We report that rapid evolution of enhancers is a universal feature of mammalian genomes. Most of the recently evolved enhancers arise from ancestral DNA exaptation, rather than lineage-specific expansions of repeat elements....... These results provide important insight into the functional genetics underpinning mammalian regulatory evolution....

  11. Quantitative analysis of enhanced malignant and benign lesions on contrast-enhanced spectral mammography.

    Science.gov (United States)

    Deng, Chih-Ying; Juan, Yu-Hsiang; Cheung, Yun-Chung; Lin, Yu-Ching; Lo, Yung-Feng; Lin, GiGin; Chen, Shin-Cheh; Ng, Shu-Hang

    2018-02-27

    To retrospectively analyze the quantitative measurement and kinetic enhancement among pathologically proven benign and malignant lesions using contrast-enhanced spectral mammography (CESM). We investigated the differences in enhancement between 44 benign and 108 malignant breast lesions in CESM, quantifying the extent of enhancements and the relative enhancements between early (between 2-3 min after contrast medium injection) and late (3-6 min) phases. The enhancement was statistically stronger in malignancies compared to benign lesions, with good performance by the receiver operating characteristic curve [0.877, 95% confidence interval (0.813-0.941)]. Using optimal cut-off value at 220.94 according to Youden index, the sensitivity was 75.9%, specificity 88.6%, positive likelihood ratio 6.681, negative likelihood ratio 0.272 and accuracy 82.3%. The relative enhancement patterns of benign and malignant lesions, showing 29.92 vs 73.08% in the elevated pattern, 7.14 vs 92.86% in the steady pattern, 5.71 vs 94.29% in the depressed pattern, and 80.00 vs 20.00% in non-enhanced lesions (p < 0.0001), respectively. Despite variations in the degree of tumour angiogenesis, quantitative analysis of the breast lesions on CESM documented the malignancies had distinctive stronger enhancement and depressed relative enhancement patterns than benign lesions. Advances in knowledge: To our knowledge, this is the first study evaluating the feasibility of quantifying lesion enhancement on CESM. The quantities of enhancement were informative for assessing breast lesions in which the malignancies had stronger enhancement and more relative depressed enhancement than the benign lesions.

  12. Recommender Systems in Technology Enhanced Learning

    NARCIS (Netherlands)

    Manouselis, Nikos; Drachsler, Hendrik; Vuorikari, Riina; Hummel, Hans; Koper, Rob

    2010-01-01

    Manouselis, N., Drachsler, H., Vuorikari, R., Hummel, H. G. K., & Koper, R. (2011). Recommender Systems in Technology Enhanced Learning. In P. B. Kantor, F. Ricci, L. Rokach, & B. Shapira (Eds.), Recommender Systems Handbook (pp. 387-415). Berlin: Springer.

  13. Variable Span Filters for Speech Enhancement

    DEFF Research Database (Denmark)

    Jensen, Jesper Rindom; Benesty, Jacob; Christensen, Mads Græsbøll

    2016-01-01

    In this work, we consider enhancement of multichannel speech recordings. Linear filtering and subspace approaches have been considered previously for solving the problem. The current linear filtering methods, although many variants exist, have limited control of noise reduction and speech...

  14. Learning in a technology enhanced world

    OpenAIRE

    Specht, Marcus

    2010-01-01

    Specht, M. (2009). Learning in a technology enhanced world. Invited talk given at the World Conference on E-learning in Corporate, Government, Healthcare & Higher Education. October, 27, 2009, Vancouver, Canada.

  15. Teacher Design Knowledge for Technology Enhanced Learning

    NARCIS (Netherlands)

    McKenney, Susan

    2014-01-01

    This presentation shares a framework for investigating the knowledge teachers need to be able to design technology-enhanced learning. Specific activities are undertaken to consider elements within the framework

  16. Enhancing Environmental Friendliness through Mobile Phone ...

    African Journals Online (AJOL)

    Enhancing Environmental Friendliness through Mobile Phone Learning. ... Journal Home > Vol 18, No 1 (2014) > ... Environmental friendly or eco-friendly refers to products or processes that are not harmful to the environment and people who ...

  17. Behavioral Therapy, Incentives Enhance Addiction Treatment

    Science.gov (United States)

    ... Research News From NIH Behavioral Therapy, Incentives Enhance Addiction Treatment Past Issues / Summer 2006 Table of Contents ... that people who are trying to end their addiction to marijuana can benefit from a treatment program ...

  18. Enhanced Brine Dewatering System, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The purpose of the Enhanced Brine Dewatering System (EBDS) is to provide an easily scalable means of completely recovering usable water from byproducts created by...

  19. Resonant metallic nanostructures for enhanced terahertz spectroscopy

    KAUST Repository

    Toma, A.

    2015-11-12

    We present our recent studies on terahertz resonant dipole nanoantennas. Exploiting the localization and enhancement capabilities of these devices, we introduce an effective method to perform terahertz spectroscopy on an extremely small number of nano-objects.

  20. Strategy to Enhance International Supply Chain Security

    National Research Council Canada - National Science Library

    2007-01-01

    .... at 1901, 1903, October 13, 2006) which require the development of a strategic plan to enhance the security of the international supply chain, including protocols for the expeditious resumption of the flow of trade following...

  1. Using synergistic exogenous phytohormones to enhance somatic ...

    African Journals Online (AJOL)

    Southern Forests: a Journal of Forest Science ... Eucalyptus spp. has been limited to germinated seeds, flowers, lignotubers or zygotic embryos. ... explants could be enhanced through pairing of synergistic exogenous plant growth regulators, ...

  2. Hippocampal Processing of Ambiguity Enhances Fear Memory.

    Science.gov (United States)

    Amadi, Ugwechi; Lim, Seh Hong; Liu, Elizabeth; Baratta, Michael V; Goosens, Ki A

    2017-02-01

    Despite the ubiquitous use of Pavlovian fear conditioning as a model for fear learning, the highly predictable conditions used in the laboratory do not resemble real-world conditions, in which dangerous situations can lead to unpleasant outcomes in unpredictable ways. In the current experiments, we varied the timing of aversive events after predictive cues in rodents and discovered that temporal ambiguity of aversive events greatly enhances fear. During fear conditioning with unpredictably timed aversive events, pharmacological inactivation of the dorsal hippocampus or optogenetic silencing of cornu ammonis 1 cells during aversive negative prediction errors prevented this enhancement of fear without affecting fear learning for predictable events. Dorsal hippocampal inactivation also prevented ambiguity-related enhancement of fear during auditory fear conditioning under a partial-reinforcement schedule. These results reveal that information about the timing and occurrence of aversive events is rapidly acquired and that unexpectedly timed or omitted aversive events generate hippocampal signals to enhance fear learning.

  3. Enhancement of Solubility and Bioavailability of Candesartan ...

    African Journals Online (AJOL)

    Purpose: To enhance the otherwise poor solubility and bioavailability of candesartan cilexetil (CDS). Methods: This ... PEG 6000-based solid dispersions showed 1st order drug release kinetics. ..... the liver due to quercetin's inhibitory effect on.

  4. Numerical Study of Electric Field Enhanced Combustion

    KAUST Repository

    Han, Jie

    2016-01-01

    Electric fields can be used to change and control flame properties, for example changing flame speed, enhancing flame stability, or reducing pollutant emission. The ions generated in flames are believed to play the primary role. Although experiments

  5. Production-enhancement partnerships: Successful business arrangements

    International Nuclear Information System (INIS)

    Coble, L.E.; Weitzel, K.R.; Attai, L.F.; Gray, K.A.

    1996-01-01

    Production-enhancement projects are creating changes in business relationships between oil and gas and service companies. The most successful projects are building partnerships. Service companies are being asked to share the risk while supplying services to enhance well performance. Risk sharing creates common project objectives and requires the service company's involvement in initial project planning, job design, and reservoir understanding. Service-work compensation is based on well- or field-performance improvement resulting from the treatment(s). This paper presents an integrated approach to the selection and prioritization of well candidates for production-enhancement jobs or treatments. Processes are illustrated, and data requirements and techniques necessary to select well candidates that provide the highest return on investment are discussed. Field examples demonstrate the techniques, critical factors, and appropriate software used by geoscience and field-operations teams to maximize benefits from production-enhancement projects

  6. Five Performance Enhancements for Hybrid Hash Join

    National Research Council Canada - National Science Library

    Graefe, Goetz

    1992-01-01

    .... We discuss five performance enhancements for hybrid hash join algorithms, namely data compression, large cluster sizes and multi-level recursion, role reversal of build and probe inputs, histogram...

  7. Enhancing Mental Readiness in Military Personnel

    National Research Council Canada - National Science Library

    Thompson, Megan M; McCreary, Donald R

    2006-01-01

    In this paper we explore how the psychological literature on stress and coping might inform military training programs to enhance "mental readiness" as a method to develop the baseline psychological...

  8. Enhancing Teacher Efficacy in Special Education.

    Science.gov (United States)

    McDaniel, Elizabeth A.; McCarthy, Holly DiBella

    1989-01-01

    A special education teacher's sense of teaching efficacy and personal teaching efficacy influences teacher motivation and effort, teacher-student interactions, and student achievement. Methods for enhancing teachers' sense of efficacy are suggested. (JDD)

  9. Enhanced Publications: Data Models and Information Systems

    Directory of Open Access Journals (Sweden)

    Alessia Bardi

    2014-04-01

    Full Text Available “Enhanced publications” are commonly intended as digital publications that consist of a mandatory narrative part (the description of the research conducted plus related “parts”, such as datasets, other publications, images, tables, workflows, devices. The state-of-the-art on information systems for enhanced publications has today reached the point where some kind of common understanding is required, in order to provide the methodology and language for scientists to compare, analyse, or simply discuss the multitude of solutions in the field. In this paper, we thoroughly examined the literature with a two-fold aim: firstly, introducing the terminology required to describe and compare structural and semantic features of existing enhanced publication data models; secondly, proposing a classification of enhanced publication information systems based on their main functional goals.

  10. Gd enhanced MRI in sensorineural hearing loss

    International Nuclear Information System (INIS)

    Takenaka, Mika; Tono, Tetsuya; Toyama, Katsuhiro; Kano, Kiyo; Morimitsu, Tamotsu

    1996-01-01

    The enhanced MRI hearing findings of the inner ear in 124 patients with sensorineural hearing loss were evaluated. MR images were obtained before and after the intravenous administration of gadolinium (0.1 mmol/kg). In three out of seventy-nine patients with unilateral healing loss, cochlear and/or the vestibular enhancement was noted on the symptomatic side. The positive cases included those with Ramsay-Hunt syndrome, mumps and so-called sudden deafness. Forty-five patients with bilateral hearing loss showed no enhancement within the inner ear. Although positive gadolinium enhancement of the inner ear may detect inflammatory lesions due to a viral infection, its incidence in sensorineural hearing loss, including cases of sudden deafness. seems to be extremely rare. (author)

  11. Is enhanced MRI helpful in brainstem infarction?

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Y. M.; Shin, G. H.; Choi, W. S. [Kyung Hee University Hospital, Seoul (Korea, Republic of)

    1994-12-15

    To determine the role of MR contrast enhancement in evaluating time course of brainstem infarction. MR imaging with IV administration of gadopentetate dimeglumine was retrospectively reviewed in 43 patients with clinically and radiologically documented brainstem infarctions. The pattern of infarction was classified into spotty and patchy. Presence of parenchymal enhancement in infarction was evaluated. By location, there were 34 pontine, 3 midbrain, 6 medullary infarctions. The age of the infarctions ranged from 1 day to 9 months, with 5 patients scanned within 3 days and 10 scanned within 2 weeks of clinical ictus. Abnormalities on T2-weighted images were encountered in every case, with spotty pattern in 14 cases and patchy pattern in 29 cases. Parenchymal contrast enhancement was seen in 9 cases(20%), primarily occurring between days 8 and 20. MR contrast enhancement in brainstem infarction was infrequent that it may not be useful in the estimation of the age of infarction.

  12. Enhancing Negotiation Skills Using Foreign Service Simulations

    Science.gov (United States)

    Opt, Susan

    2017-01-01

    Courses: Conflict communication, negotiation, small group. Objective: This activity will enhance students' awareness and critique of their own negotiation behaviors. A list of references and suggested readings is included.

  13. Signal enhancement with variable span linear filters

    CERN Document Server

    Benesty, Jacob; Jensen, Jesper R

    2016-01-01

    This book introduces readers to the novel concept of variable span speech enhancement filters, and demonstrates how it can be used for effective noise reduction in various ways. Further, the book provides the accompanying Matlab code, allowing readers to easily implement the main ideas discussed. Variable span filters combine the ideas of optimal linear filters with those of subspace methods, as they involve the joint diagonalization of the correlation matrices of the desired signal and the noise. The book shows how some well-known filter designs, e.g. the minimum distortion, maximum signal-to-noise ratio, Wiener, and tradeoff filters (including their new generalizations) can be obtained using the variable span filter framework. It then illustrates how the variable span filters can be applied in various contexts, namely in single-channel STFT-based enhancement, in multichannel enhancement in both the time and STFT domains, and, lastly, in time-domain binaural enhancement. In these contexts, the properties of ...

  14. Binaural enhancement for bilateral cochlear implant users.

    Science.gov (United States)

    Brown, Christopher A

    2014-01-01

    Bilateral cochlear implant (BCI) users receive limited binaural cues and, thus, show little improvement to speech intelligibility from spatial cues. The feasibility of a method for enhancing the binaural cues available to BCI users is investigated. This involved extending interaural differences of levels, which typically are restricted to high frequencies, into the low-frequency region. Speech intelligibility was measured in BCI users listening over headphones and with direct stimulation, with a target talker presented to one side of the head in the presence of a masker talker on the other side. Spatial separation was achieved by applying either naturally occurring binaural cues or enhanced cues. In this listening configuration, BCI patients showed greater speech intelligibility with the enhanced binaural cues than with naturally occurring binaural cues. In some situations, it is possible for BCI users to achieve greater speech intelligibility when binaural cues are enhanced by applying interaural differences of levels in the low-frequency region.

  15. Systems and methods for enhancing optical information

    Science.gov (United States)

    DeVore, Peter Thomas Setsuda; Chou, Jason T.

    2018-01-02

    An Optical Information Transfer Enhancer System includes a first system for producing an information bearing first optical wave that is impressed with a first information having a first information strength wherein the first optical wave has a first shape. A second system produces a second optical wave. An information strength enhancer module receives the first and said second optical waves and impresses the first optical wave upon the second optical wave via cross-phase modulation (XPM) to produce an information-strength-enhanced second optical wave having a second information strength that is greater than the first information strength of the first optical wave. Following a center-wavelength changer by an Optical Information Transfer Enhancer System improves its performance.

  16. Viability of Biopolymers for Enhanced Oil Recovery

    NARCIS (Netherlands)

    Sveistrup, Marte; van Mastrigt, Frank; Norrman, Jens; Picchioni, Francesco; Paso, Kristofer

    2016-01-01

    Xanthan gum and scleroglucan are assessed as environmentally friendly enhanced oil recovery (EOR) agents. Viscometric and interfacial tension measurements show that the polysaccharides exhibit favorable viscosifying performance, robust shear tolerance, electrolyte tolerance, and moderate

  17. Enhancer Evolution across 20 Mammalian Species

    Science.gov (United States)

    Villar, Diego; Berthelot, Camille; Aldridge, Sarah; Rayner, Tim F.; Lukk, Margus; Pignatelli, Miguel; Park, Thomas J.; Deaville, Robert; Erichsen, Jonathan T.; Jasinska, Anna J.; Turner, James M.A.; Bertelsen, Mads F.; Murchison, Elizabeth P.; Flicek, Paul; Odom, Duncan T.

    2015-01-01

    Summary The mammalian radiation has corresponded with rapid changes in noncoding regions of the genome, but we lack a comprehensive understanding of regulatory evolution in mammals. Here, we track the evolution of promoters and enhancers active in liver across 20 mammalian species from six diverse orders by profiling genomic enrichment of H3K27 acetylation and H3K4 trimethylation. We report that rapid evolution of enhancers is a universal feature of mammalian genomes. Most of the recently evolved enhancers arise from ancestral DNA exaptation, rather than lineage-specific expansions of repeat elements. In contrast, almost all liver promoters are partially or fully conserved across these species. Our data further reveal that recently evolved enhancers can be associated with genes under positive selection, demonstrating the power of this approach for annotating regulatory adaptations in genomic sequences. These results provide important insight into the functional genetics underpinning mammalian regulatory evolution. PMID:25635462

  18. Contextualising the National Development Plan for enhanced ...

    African Journals Online (AJOL)

    ... and Development. Strategy, Integrated Development Planning, enhanced service delivery .... Penderis (2012: 7) proffers that there is a vast body of ..... the various chapters, objectives and actions of the ..... financing and formulation of the ten.

  19. Resonant metallic nanostructures for enhanced terahertz spectroscopy

    KAUST Repository

    Toma, A.; Tuccio, S.; Prato, M.; De Donato, F.; Perucchi, A.; Di Pietro, P.; Marras, S.; Liberale, Carlo; Zaccaria, R. Proietti; De Angelis, F.; Manna, L.; Lupi, S.; Di Fabrizio, Enzo M.; Razzari, L.

    2015-01-01

    We present our recent studies on terahertz resonant dipole nanoantennas. Exploiting the localization and enhancement capabilities of these devices, we introduce an effective method to perform terahertz spectroscopy on an extremely small number

  20. Enhanced Time Out: An Improved Communication Process.

    Science.gov (United States)

    Nelson, Patricia E

    2017-06-01

    An enhanced time out is an improved communication process initiated to prevent such surgical errors as wrong-site, wrong-procedure, or wrong-patient surgery. The enhanced time out at my facility mandates participation from all members of the surgical team and requires designated members to respond to specified time out elements on the surgical safety checklist. The enhanced time out incorporated at my facility expands upon the safety measures from the World Health Organization's surgical safety checklist and ensures that all personnel involved in a surgical intervention perform a final check of relevant information. Initiating the enhanced time out at my facility was intended to improve communication and teamwork among surgical team members and provide a highly reliable safety process to prevent wrong-site, wrong-procedure, and wrong-patient surgery. Copyright © 2017 AORN, Inc. Published by Elsevier Inc. All rights reserved.